Surgical needle abstract
In a surgical needle, marks of welding are left as they are on
a welded portion between needle and pipe members so that the welded
portion has a surface distinguishable from peripheral surfaces of
the respective needle and pipe members. The welded portion may be
composed of a plurality of peripherally spaced welded parts. In
a manufacturing method of the surgical needle, a beam energy is
applied from a beam energy emitting arrangement, toward an abutting
line between the needle and pipe members, from a direction substantially
perpendicular to the needle and pipe members, thereby welding them
to each other. In a manufacturing apparatus, a rotational support
arrangement is provided for supporting the needle and pipe members
in such a manner that end faces of the respective needle and pipe
members are abutted against each other at a location coincident
with an optical axis of the laser beam, and for rotating the needle
and pipe members about their respective axes.
Surgical needle claims
What is claimed is:
1. A surgical needle comprising a needle member, a pipe member
with a bore therein having an axis and a welded connecting means
for attaching said pipe member to a proximal end of said needle
member formed at a junction between the needle member and the pipe
member, said welded connecting means comprising a plurality of peripherally
spaced welded parts formed at the junction between the needle member
and the pipe member, whereby a suture may be inserted into the bore
of the pipe member and secured and wherein the welded connecting
means is broken when a tension force is applied to the suture in
a direction intersecting the axis.
2. A surgical needle according to claim 1 wherein the welded connecting
means has a depth of penetration into the pipe member which is less
than the radial wall thickness of the pipe member.
Surgical needle description
BACKGROUND OF THE INVENTION
The present invention relates to a surgical needle of eyeless type,
a method of manufacturing the needle, and an apparatus for carrying
out the method.
A surgical needle of eyeless type is known, in which a bore is
formed in a proximal end of the needle and extends along an axis
thereof. An end of a suture is inserted into the bore in the proximal
end of the needle, and the proximal end of the needle is then staked,
whereby the suture can be attached to the needle. Usually, there
are known two methods of manufacturing the surgical needle having
the proximal end formed therein with the bore.
First one of the two known methods is disclosed in Japanese patent
application Laid-Open Nos. 52-111294 60-170590 and 60-184485 Japanese
Patent Publication No. 61-58172 Japanese Utility Model Publication
No. 56-37918 and Japanese Utility Model application Laid-Open No.
55-43691 in which a drill or a beam energy is used to form the
bore in the proximal end of the surgical needle. It is difficult
for the first method, however, to form the small diameter bore correctly
along the axis of the needle which is also small in diameter.
The second method is disclosed in Japanese Utility Model Publication
No. 28-3184 in which a pipe member is welded to an end face of
the proximal end of a needle member. In the second method, since
a hollow portion of the pipe member can be used as a bore for attaching
a suture, the bore-forming operation like the first method is dispensed
with. Further, it is easy for the second method to manufacture a
small diameter surgical needle having therein a small diameter bore
extending along the axis of the surgical needle. The Japanese utility
model does not specifically describe in what manner the pipe member
is welded to the proximal end of the needle member. At that time,
however, welding has practically been performed in the following
manner. That is, the pipe member has been welded to the proximal
end of the needle member by means of a so-called butt welding, in
which an end face of the pipe member is butted under pressure against
an end face of the proximal end of the needle member, and portions
of the respective needle and pipe members adjacent the junction
therebetween are welded to each other by heat generated due to electric
resistance between both the end faces. It is necessary for the butt
welding, however, to apply force to the pipe member and the needle
member along an axis common to them during the welding operation
such that the pipe member and the needle member are urged against
each other. Because of such force, melted material tends to be forced
out to form flash, so that a step of trimming is required after
the welding operation. This trimming operation is troublesome because
the surgical needle is very small in diameter, resulting in an increase
of the manufacturing cost. Moreover, the melted metal flows under
the urging force also into the hollow portion of the pipe member,
so that variation occurs in the depths of the bores in the respective
surgical needles, which bores are formed respectively by the hollow
portions of the pipe members.
Additionally, as the relevant prior art, there is Japanese patent
application Laid-Open No. 61-45745 corresponding to U.S. Ser. No.
632343 filed on July 19 1984 which discloses coloring of surgical
needles. In this connection, there is also U.S. Ser. No. 905521
filed on Sept. 10 1986 in the name of the same assignee as this
application.
Japanese Patent Publication No. 58-39544 and Japanese patent application
Laid-Open Nos. 49-61980 and 50-119487 disclose a technique in which
the suture is drawn out of the surgical needle in order to simplify
and facilitate separation between the surgical needle and the suture
after the suture has been pierced through a bodily tissue at the
surgical operation. Japanese Utility Model application Laid-Open
No. 61-109505 discloses a technique in which a part of the suture
adjacent the surgical needle is weakened locally. Furthermore, Japanese
Utility Model Application Laid-Open No. 61-109506 discloses a technique
in which the suture is connected to the surgical needle by a special
connector element.
Japanese Utility Model Publication No. 60-25219 discloses a technique
for annealing the proximal end of the surgical needle formed of
austenitic stainless steel.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a surgical needle which
is easy in manufacturing and is low in production cost.
It is another object of the invention to provide a method of manufacturing
the surgical needle.
It is still another object of the invention to provide an apparatus
for carrying out the method.
According to the invention, there is provided a surgical needle
comprising a needle member, a pipe member arranged at a proximal
end of the needle member and a welded portion formed between the
needle and pipe members, wherein marks of welding are left as they
are on the welded portion so that the welded portion has a surface
distinguishable from peripheral surfaces of the respective needle
and pipe members.
According to the invention, there is also provided a surgical needle
comprising a needle member, a pipe member arranged at a proximal
end of the needle member, and a plurality of peripherally spaced
welded parts formed at a junction between the needle and pipe members.
According to the invention, there is further provided a method
of manufacturing a surgical needle, comprising the steps of: abutting
an end face of a pipe member against a proximal end face of a needle
member to form an abutting line which is annular in appearance;
and supplying a beam energy from beam energy emitting means, toward
the abutting line, from a direction substantially perpendicular
to the needle and pipe members, thereby welding the needle and pipe
members to each other to form a welded portion therebetween.
According to the invention, there is provided an apparatus for
manufacturing a surgical needle, comprising:
(a) beam energy emitting means;
(b) rotational support means for supporting a needle member and
a pipe member in such a manner that axes of the respective needle
and pipe members extend perpendicularly to an axis of a beam energy
emitted from the beam energy emitting means and that an end face
of the needle member and an end face of the pipe member are abutted
against each other at a location coincident with the axis of the
laser beam, the rotational support means also rotating the needle
and pipe members about their respective axes; and
(c) drive means for giving rotation to the rotational support means.
According to the invention, there is also provided an apparatus
for manufacturing a surgical needle, comprising a laser beam generating
source arranged stationarily, a laser beam emitting section receiving
a laser beam from the laser beam generating source through an optical
fiber, the laser beam emitting section condensing the laser beam
to emit the condensed laser beam, guide means at least including
an arcuate portion, moving means for moving the laser beam emitting
section along the guide means while maintaining such a posture that
an optical axis of the laser beam emitted from the laser beam emitting
section passes through a central axis of a radius of curvature of
the arcuate portion of the guide means, and support means supporting
the needle and pipe members while maintaining them stationary in
such a manner that the needle and pipe members are abutted against
each other at a location substantially coincident with a plane including
the optical axis of the laser beam and that the axes of the respective
needle and pipe members are coincident with the central axis of
the radius of curvature of the guide means.
According to the invention, there is further provided an apparatus
for manufacturing a surgical needle, comprising a laser beam generating
source arranged stationarily, dividing means for dividing a laser
beam from the laser beam generating source into a plurality of laser
beams, a plurality of laser beam emitting sections respectively
receiving the laser beams divided by the dividing means, through
respective optical fibers, to emit the respective laser beams, and
support means for stationarily supporting a needle member and a
pipe member in such a manner that the needle and pipe members are
abutted against each other at a location substantially coincident
with a plane including optical axes of the respective laser beams.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan view showing an embodiment of a method
of welding a needle member and a pipe member to each other, according
to the invention;
FIG. 2 is a fragmental enlarged cross-sectional view showing the
welded portion obtained by the welding method illustrated in FIG.
1;
FIG. 3 is a plan view of a surgical needle after completion of
welding in accordance with the method illustrated in FIG. 1;
FIG. 4 is a cross-sectional view showing the welded portion of
the surgical needle illustrated in FIG. 3;
FIG. 5 is a view showing the surgical needle which is bent into
a curved form and to which a suture is attached, after completion
of welding;
FIG. 6 is a fragmental enlarged schematic view showing a preferred
manner of supplying pulses of a laser beam;
FIG. 7 is a perspective view showing the needle and pipe members
tack-welded to each other, before the regular welding is carried
out;
FIG. 8 is a schematic plan view showing an example of an annealing
manner after completion of welding;
FIG. 9 is a view similar to FIG. 8 but showing another example
of the annealing manner;
FIG. 10 is a view similar to FIG. 8 but showing still another
example of the annealing manner;
FIG. 11 is a schematic view showing a manner in which only a multiplicity
of pipe members are annealed, the annealing being carried out before
welding;
FIGS. 12 through 15 are cross-sectional views respectively showing
various aspects of the welded portion;
FIGS. 16 and 17 are views showing, in due order, a suture operation
carried out by the use of the surgical needle provided with one
of the welded portions shown respectively in FIGS. 12 through 15;
FIG. 18 is a view showing another aspect of a surgical needle provided
with one of the welded portions illustrated respectively in FIGS.
12 through 15;
FIG. 19 is a top plan view showing an embodiment of an apparatus
for carrying out the method according to the invention, an arrangement
of respective chuck mechanisms for a needle member and a pipe member
and other mechanisms being omitted for clarification;
FIG. 20 is a cross-sectional view taken along line XX--XX in FIG.
19;
FIG. 21 is a fragmental plan view of the chuck mechanisms for the
respective needle and pipe members employed in the apparatus illustrated
in FIG. 19;
FIG. 22 is a front elevational view of the chuck mechanisms illustrated
in FIG. 21;
FIG. 23 is an end view of the chuck mechanism for the pipe member,
illustrated in FIGS. 21 and 22;
FIG. 24 is an end view of the chuck mechanism for the needle member,
illustrated in FIGS. 21 and 22;
FIG. 25 is an enlarged fragmental view of a V-shaped groove illustrated
in FIG. 23 the pipe member being set in the V-shaped groove;
FIG. 26 is an enlarged fragmental view of a V-shaped groove illustrated
in FIG. 24 the needle member being set in the V-shaped groove;
FIG. 27 is a cross-sectional view taken along line XXVII--XXVII
in FIG. 19;
FIG. 28 is a cross-sectional view taken along line XXVIII--XXVIII
in FIG. 19;
FIG. 29 is a partially cross-sectional enlarged fragmental view
of a second moving mechanism illustrated in FIG. 19;
FIG. 30 is a plan view of another aspect of means for supporting
and rotating a needle member and a pipe member;
FIG. 31 is a cross-sectional view taken along line XXXI--XXXI in
FIG. 30;
FIG. 32 is a front elevational view showing a surgical needle manufacturing
apparatus according to another embodiment of the invention; and
FIG. 33 is a vertical cross-sectional view of the apparatus illustrated
in FIG. 32.
DETAILED DESCRIPTION
Referring to FIGS. 1 through 5 there is shown a surgical needle
manufacturing method according to an embodiment of the invention.
As shown in FIG. 1 a straight needle member 1 and a straight pipe
member 2 are first prepared These needle and pipe members 1 and
2 are formed of austenitic stainless steel having advantages subsequently
to be described. The needle member 1 has one end thereof which is
formed with a planar end face 1a extending perpendicularly to an
axis of the needle member 1. The other end of the needle member
1 is formed into a pointed end 1b. The pipe member 2 is formed in
the following manner That is, a rectangular strip is curled into
a tubular form such that one side edge of the strip is abutted against
the other side edge. Then, the one and other side edges are welded
to each other to form a tube. Subsequently, the tube is drawn through
drawing dies to reduce the diameter of the tube until the diameter
is brought to a value equal to the outer diameter of the needle
member 1. The diameter-reduced tube is then cut into tube pieces
each having a predetermined length. In this manner, the above pipe
member 2 is formed by each of the cut tube pieces. The length of
the pipe member 2 is substantially equal to the depth of a bore
in a surgical needle that is an intended final product. The pipe
member 2 is formed at its both ends respectively with planar end
faces 2a and 2b extending perpendicularly to the axis of the pipe
member 2.
The needle and pipe members 1 and 2 are chucked respectively by
a pair of chuck means arranged respectively on a pair of rotary
structures independent of each other. The pair of chuck means and
the pair of rotary structures are not shown in FIG. 1 but will
be described later with reference to FIGS. 19 through 24. When the
needle and pipe members 1 and 2 are chucked respectively by the
chuck means, one of the planar faces 2a of the pipe member 2 and
the planar face 1a of the needle member 1 are abutted against each
other such that a single annular line 3 is seen from the outside,
which is formed between the respective outer peripheral surfaces
of the needle and pipe members 1 and 2.
With the planar faces 1a and 2a abutted against each other, the
needle and pipe members 1 and 2 are welded to each other by a laser
beam L emitted from a laser beam emitting unit 10. The laser beam
emitting unit 10 comprises, as its principal components, a generating
source 11 of a collimated laser beam Lo, and a condenser optical
system 12 including a convex lens for condensing the collimated
laser beam Lo emitted from the generation source 11 onto peripheral
surfaces of portions of the respective needle and pipe members 1
and 2 adjacent the above-mentioned abutting line 3.
It is shown in FIG. 2 that a region on the peripheral surface of
the needle member 1 which is supplied with the condensed laser
beam L, is substantially equal in area to that on the peripheral
surface of the pipe member 2 which is supplied with the condensed
laser beam L. However, the laser receiving region on the needle
member 1 may be larger in area than that on the pipe member 2 in
consideration of the fact that the needle member 1 is larger in
heat capacity than the pipe member 2.
By application of the laser beam L, portions of the respective
needle and pipe members 1 and 2 which are adjacent the respective
end faces 1a and 2a abutted against each other, are melted. After
melting, the melted portions are cooled and solidified, thereby
completing connection or welding between the needle and pipe members
1 and 2. The welding due to the laser beam L is carried out only
at a single location on the abutting line 3 if the needle and pipe
members 1 and 2 are stationary. In the illustrated embodiment, therefore,
with the needle and pipe members 1 and 2 maintained abutted against
each other, pulses of the laser beam L are successively applied
to the abutting line 3 at intervals of a short period of time, while
rotating the rotary structures respectively supporting the needle
and pipe members 1 and 2 at the same rotational speed, thereby successively
carrying out welding along the entire circumferential length of
the abutting line 3. As a result, as shown in FIGS. 3 and 4 a straight
surgical needle 5 is formed, which is provided with an annular welded
portion 4 and which is formed with a bore 5a.
The surgical needle 5 provided with the bore 5a is bent into a
curved form by a known bending device as disclosed in Japanese Patent
Publication No. 60-18256. Further, with an end of a suture inserted
into the bore 5a, the proximal end of the surgical needle 5 is staked
by a staking device disclosed in U.S. Pat. No. 4722384 or the
like. As a consequence, there is provided a curved surgical needle
7 having attached thereto a suture 6 that is a final product as
shown in FIG. 5.
In the welding described above, the energy of the laser beam L
per one pulse, the time interval between each pair of adjacent pulses,
a focal position F (see FIG. 2) and the like are adjusted in such
a manner that the penetration depth of the welded portion 4 is substantially
consistent with the radial wall thickness of the pipe member 2.
Additionally, as shown in FIG. 2 if the focal position F of the
condenser optical system 12 is located substantially at the radial
center or the vicinity thereof, of the radial wall thickness of
the pipe member 2 the consumptive energy of the laser beam L can
be reduced.
Since the laser beam L can supply energy of a controlled amount
to the junction between the needle and pipe members 1 and 2 it
is possible to carry out welding along the entire circumferential
length of the abutting line 3 substantially uniformly, that is,
with a constant weld penetration depth.
It is unnecessary for the welding due to the laser beam to apply
force to the needle and pipe members 1 and 2 toward each other to
thereby press them against each other. It is mere necessary to maintain
the needle and pipe members 1 and 2 abutted against each other.
Accordingly, an amount by which the melted metal penetrates into
the cavity within the pipe member 2 is extremely small, as compared
with the electric resistance welding. Therefore, the cavity within
the pipe member 2 remains substantially unchanged as the bore 5a
for attaching the suture 6 making it possible to maintain the depth
of the bore 5a constant.
Moreover, since the above-mentioned urging force is not applied
to the needle and pipe members 1 and 2 no flash occurs which projects
outwardly. Rather, due to the facts that minute spaces are formed
between the abutted end faces 1a and 2a of the respective needle
and pipe members 1 and 2 by minute irregularities on the end faces
1a and 2a and by minute dust interposed between the end faces 1a
and 2a and are filled with a part of the melted metal, and that
a part of the melted metal is slightly drawn toward the cavity within
the pipe member 2 when the melted metal is cooled, the welded portion
4 caves in from the outer peripheral surfaces of the respective
needle and pipe members 1 and 2 by few micron meters or to the extent
slightly more than few micron meters, as shown in FIG. 3. The caving-in
amount is exaggeratedly shown in FIG. 3. As a result, it is possible
for the invention to dispense with the trimming step.
Since the marks of welding are left on the surface of the above-mentioned
annular welded portion 4 as shown in FIG. 5 it is possible to
distinguish, in appearance, the welded portion 4 from the peripheral
surfaces of the respective needle and pipe members 1 and 2. There
are two aspects of the surface of the welded portion 4.
The first aspect of the surface of the welded portion 4 is obtained
in the following manner That is, as shown in FIG. 1 inert gas such
as argon gas, nitrogen gas or the like is blown at slow speed from
a pipe 8 extremely small in diameter, against a region on the peripheral
surfaces of the respective needle and pipe members 1 and 2 to which
region the laser beam L is applied. By doing so, the surface of
the welded part 4 is prevented from being oxidized and is formed
into a mirror surface, so that the surface of the welded portion
4 glistens as compared with the surfaces of the respective needle
and pipe members 1 and 2. Moreover, when the welding is carried
out in a vacuum, the surface of the welded portion 4 is likewise
formed into a mirror surface.
The second aspect of the surface of the welded portion 4 is obtained
in such a manner that welding is carried out in the atmosphere without
the inert gas being blown against the surfaces of the respective
needle and pipe members 1 and 2. In this case, an oxide film is
formed on the surface of the welded portion 4 so that the surface
of the welded portion 4 is distinguished from the peripheral surfaces
of the respective needle and pipe members 1 and 2.
The surface of the welded portion 4 cannot be vanished by electrolytic
polishing or chemical polishing, unless the surface is mechanically
ground or polished.
The ring-like welded portion 4 serves as a mark when, for example,
the pipe member 2 is staked, so that it can be ensured that a part
(designated by the character 2a in FIG. 5) of the pipe member 2
spaced a predetermined distance from the welded portion 4 is staked.
This makes it possible to prevent occurrence of cracks or the like
in the pipe member 2 due to staking of the welded portion 4 or a
part very close thereto. Moreover, the ring-like welded portion
4 serves also as a mark by which when a doctor clamps the surgical
needle with a chuck jig at a surgical operation, he can clamp the
surgical needle while keeping away from the pipe member 2 which
is low in strength.
It is preferable that pulses of the laser beam L are applied in
a manner as shown in FIG. 6. In FIG. 6 a region of melting occurring
due to a single pulse of the laser beam L is indicated by a circle
C. The pulses of the laser beam L are successively outputted at
intervals of a short period of time. Since the needle and pipe members
1 and 2 are rotated about their respective axes simultaneously with
the output of the pulses, the pulses are successively applied to
the needle and pipe members 1 and 2 along the abutting line 3 at
narrow angular intervals. Thus, welded parts produced by the respective
pulses are overlapped with each other. Since a part of the needle
and pipe members 1 and 2 to which a first one of the pulses of
the laser beam L is to be applied, is at the room temperature and
is cool, an amount of melting at the part is small when the laser
beam L is applied to the part. Accordingly, the region of melting
appearing on the surface is narrow, and the depth of penetration
is shallow. The depth of penetration does not reach a position corresponding
to the radial wall thickness of the pipe member 2 but occupies
only the outer surface layer. Thus, the welding is incomplete. A
second pulse of the laser beam L is applied to a second part immediately
adjacent the part to which the first pulse is applied, at an interval
of an extremely short period of time Since the second part is raised
in temperature by the first pulse, the second part increases in
amount of melting when the second pulse is applied to the second
part, so that depth of penetration increases. At a part to which
a pulse of the laser beam L subsequent to several pulses is applied,
as shown in FIG. 2 the depth of penetration of the welded portion
4 is substantially equal to the radial wall thickness of the pipe
member 2 so that the welded portion 4 is locally brought to a complete
welded form. Accordingly, if it is desired to carry out the complete
welding along the entire circumferential length of the abutting
line 3 in other words, if it is desired that welding is carried
out over the entire region of the end face 2a of the pipe member
2 as shown in FIG. 6 the pulses of the laser beam L are again
applied along the abutting line 3 by a predetermined length from
the part to which the first pulse is applied.
The energy of the laser beam L may be weak at the initial few pulses
In this case, the energy of the laser beam L is gradually raised
to a steady energy level. By doing so, the length of the initial
incomplete welded part along the abutting line 3 is increased, thereby
obtaining a tack-welding effect. The tack-welding effect will be
described later in detail with reference to FIG. 7 which remarkably
shows the tack-welding.
Moreover, the pulses of the laser beam L may be applied through
a predetermined length from the END position shown in FIG. 6 while
gradually weakening the energy of the laser beam L. By doing so,
it is possible to prevent a mark, like a crater, of the last pulse
of the laser beam L from being left on the welded portion 4.
By the way, when the laser beam L is applied to the junction between
the needle and pipe members 1 and 2 to successively carry out welding
along the abutting line 3 a bending force acts to the needle and
pipe members 1 and 2 at the initial stage of the welding step. The
bending force tends to angularly move the needle and pipe members
1 and 2 about the part at which welding has already been completed,
so that the needle and pipe members 1 and 2 are brought into misalignment
with each other. If the needle and pipe members 1 and 2 are chucked
respectively by a pair of chucks at respective positions remote
from the abutting line 3 the needle and pipe members 1 and 2 are
subject to the bad influence of the bending force, so that there
may be a case where the needle and pipe members 1 and 2 are welded
to each other while being maintained misaligned. This deficiency
can be dissolved in the following manner. That is, prior to the
regular welding, as shown in FIG. 7 a single short pulse of the
laser beam is applied to each of a plurality of, for example, three
or more locations on the abutting line 3 which are equidistantly
spaced circumferentially from each other. Since the pulses of the
laser beam are supplied respectively to the locations on the abutting
line 3 under the condition that the needle and pipe members 1 and
2 are at the room temperature and are cool, the depth of penetration
of each of welded parts 4' is shallow. Accordingly, substantially
no bending force is produced due to the welded parts 4'. When the
regular welding is carried out as shown in FIG. 6 with the needle
and pipe members 1 and 2 tack-welded to each other, even if a bending
force occurs temporarily due to the regular welding, the tack-welded
parts 4' serve as resistance to the bending force. Thus, welding
can be effected without the needle and pipe members 1 and 2 being
brought into misalignment with each other.
Since the austenitic stainless steel is used as the material of
the needle and pipe members 1 and 2 the surgical needle 7 is excellent
in corrosion resistance. Moreover, welding due to the laser beam
L is accompanied with local rapid heating and rapid cooling. However,
the austenitic stainless steel is not hardened by the rapid cooling,
but is softened Therefore, it is possible to prevent occurrence
of cracks in the vicinity of the welded portion 4 due to the hardening
by the rapid cooling during welding.
The welded portion 4 is soft as compared with the needle and pipe
members 1 and 2. Accordingly, when a bending force is applied to
the surgical needle 7 the needle 7 is bent at an acute angle at
the welded part 4 so that there may be a case where cracks occur
in the welded portion 4 or the welded portion 4 is damaged In view
of this, when welding has been completed, as shown in FIG. 8 either
one of the laser beam emitting unit 10 and the needle and pipe members
1 and 2 is moved in a direction perpendicular to the aligned axes
of the respective needle and pipe members 1 and 2 thereby moving
the peripheral surfaces of the respective needle and pipe members
1 and 2 away from the focal position, that is, away from the laser
beam emitting unit 10. Under this condition, if the laser beam L
is applied to the needle and pipe members 1 and 2 while rotating
them, the spot area to which the laser beam L is applied is larger
than that during the welding. By this reason, a region designated
by the reference numeral 9 in FIG. 8 which is wider than the welded
portion 4 and which extends along the welded portion 4 is annealed
at a temperature lower than the welding temperature and is softened.
Thus, when a bending force is applied to the surgical needle 7
deformation occurs not only in the welded portion 4 but also in
the annealing region 9 so that the surgical needle 7 is bent as
a whole into a curved form. Accordingly, it can be ensured to prevent
occurrence of cracks in the welded portion 4 and destruction thereof.
Further, after annealing at the region 9 has been completed, the
chuck is removed from the pipe member 2 and the rotary structure
supporting the needle member 1 is moved axially thereof or in a
direction indicated by the arrow in FIG. 8 while the needle member
1 is maintained chucked. At the same time, the needle and pipe members
1 and 2 are rotated about their respective axes, thereby enabling
the entire length of the pipe member 2 to be annealed by the laser
beam L. This makes it possible to prevent cracks from occurring
when the pipe member 2 is staked to attach the suture to the surgical
needle 7 and also makes it possible to increase the attaching strength
of the suture. The end of the pipe member 2 on the side opposite
to the welded portion 4 may not necessarily be softened.
Moreover, annealing may be carried out as shown in FIG. 9. That
is, by moving the needle and pipe members 1 and 2 or by moving
the laser beam emitting unit 10 the peripheral surfaces of the
needle and pipe members 1 and 2 are moved to a position closer to
the laser beam emitting unit 10 than the focal position, so that
the spot area increases to which the laser beam L is applied. Other
arrangement of the embodiment shown in FIG. 9 is the same as that
shown in FIG. 8.
Furthermore, annealing may be effected as shown in FIG. 10. That
is, after welding, a flame of a burner 10A is used to anneal the
vicinity of the welded portion 4 and the pipe member 2.
Further, annealing may be performed as shown in FIG. 11. That is,
prior to welding, a multiplicity of pipe members are wrapped up
in a stainless steel foil 15. The pipe members wrapped up in the
foil 15 are gotten into an electric furnace 10B and are heated thereby.
Alternatively, the pipe members wrapped up in the foil 15 are heated
from the outside by the burner shown in FIG. 10. In this manner,
only the pipe members are annealed together. The volume of the multiplicity
of pipe members is extremely small. For example, the volume of ten
thousand pipe members is only 1 cm.sup.3. Accordingly, the annealing
method illustrated in FIG. 11 makes it possible to uniformly and
inexpensively anneal a large quantity of pipe members for a short
period of time without the pipe members being oxidized.
Welding due to the laser beam may be carried out partially with
respect only to a portion or portions of the entire region of the
end face of the pipe member 2. For example, the welding may be carried
out along the entire circumferential length of the abutting line
3 in such a manner that the depth of penetration is shallower than
the radial wall thickness of the pipe member 2. Moreover, the welding
may be carried out with respect only to a predetermined angular
extent or extents along the abutting line 3.
In each of embodiments shown respectively in FIGS. 12 through 15
welding is carried out with respect only to predetermined angular
extents along the abutting line 3 in order to enable a surgical
needle to have an especial function. The needle member 1 is bent
into a curved form after or before welding. In FIGS. 12 through
15 the inside of the curved form is designated by the character
"I", while the outside of the curved form is designated
by the character "O", in order to facilitate explanation
of welded positions.
In the embodiment illustrated in FIG. 12 no laser beam is applied
to both the inside "I" and the outside "O" so
that two welded parts 4 and 4 are formed by the laser beam. The
two welded parts 4 and 4 are angularly displaced by 90 degrees from
the inside "I" and the outside "O". Each welded
part 4 has an angular extent of the order of 70 to 80 degrees, and
has the depth of penetration of the order of a third or a fourth
of the radial wall thickness of the pipe member 2.
In the embodiment illustrated in FIG. 13 two welded parts 4 and
4 are formed respectively in relatively narrow angular extents.
The two welded parts 4 and 4 are angularly displaced by 90 degrees
from the inside "I" and the outside "O". The
depth of penetration of each welded part 4 is substantially equal
to the radial wall thickness of the pipe member 2.
In the embodiment illustrated in FIG. 14 except for the outside
"O" of the curved form, three welded parts 4 are formed
respectively at three locations circumferentially equidistantly
spaced from each other. Each of the welded parts 4 has an angular
extent which is relatively small, and has the depth of penetration
substantially equal to the radial wall thickness of the pipe member
2.
In the embodiment illustrated in FIG. 15 four welded parts 4 are
formed. Two of the four welded parts 4 are angularly displaced by
45 degrees from the inside "I", and the remaining two
parts 4 are angularly displaced by 45 degrees from the outside "O".
Each welded part 4 has a relatively small angular extent, and has
the depth of penetration substantially equal to the radial wall
thickness of the pipe member 2.
For the surgical needle provided with the welded parts 4 in one
of the embodiments illustrated respectively in FIGS. 12 through
15 it is possible to maintain the tension strength in the direction
along the aligned axes of the respective needle and pipe members
1 and 2 at a sufficient level. However, the welded parts 4 are weak
in bending strength. Such characteristic is positively utilized,
thereby enabling the following operational manner to be adopted.
That is, a doctor first clamps a portion of the surgical needle
7 adjacent the proximal end thereof, by means of a chuck jig 18.
Only a clamping section of the chuck jig 18 is shown in FIG. 16.
The surgical needle 7 is pierced through two parts of the bodily
tissue cut by a bistoury. Then, the chuck jig 18 is once removed
from the surgical needle 7 and again clamps a portion of the surgical
needle 7 adjacent a distal end thereof. As shown in FIG. 17 with
the axis of the pipe member 2 substantially aligned with the suture
6 the surgical needle 7 is pulled until the opposite end portions
of the suture 6 coming out of the bodily tissue are brought to their
respective desired lengths. Subsequently, as shown in FIG. 17 the
surgical needle 7 is angularly moved through 90 degrees about a
point at which the suture 6 is connected to the pipe member 2 such
that the axis of the pipe member 2 is substantially perpendicular
to the suture 6. Under such condition, the doctor clamps the suture
6 with fingers 19 of his hand which is not holding the chuck jig
18. Then, the doctor pulls the surgical needle 7 in the direction
indicated by the arrow in FIG. 17. By doing so, a bending stress
is applied to the welded parts 4 to destroy the same, whereby the
surgical needle 7 is disassembled into the needle member 1 and the
pipe member 2 having attached thereto the suture 6. Thus, the operation
of cutting the suture 6 prior to the operation of tying the suture
6 can be dispensed with, making it possible to enhance the operability
at the surgical operation.
It is to be noted here that, in each of the embodiments illustrated
respectively in FIGS. 12 through 15 the tension force applied to
the suture 6 acts such that one of non-welded portions is brought
to the tension side. By doing so, the pipe member 2 tends to be
angularly moved about the non-welded portion, so that destruction
of the welded parts 4 is facilitated due to the principles of the
lever. In the actual suture operation, the doctor's hand holding
the chuck jig 18 is twisted unnaturally in the state indicated by
the phantom lines in FIG. 17. When the surgical needle 7 is angularly
moved through 90 degrees about the point at which the suture 6 is
connected to the pipe member 2 that is, when the surgical needle
7 is angularly moved to the position indicated by the solid lines
in FIG. 17 the doctor's hand is in the natural state. Accordingly,
it is convenient that the outside "O" of the curved form
is brought to the tension side. To this end, it is preferable that
the outside "O" is brought to the non-welded part, as
shown in FIGS. 12 through 15.
In order to show that the surgical needle can be applied to the
special suture operational method as described above, the peripheral
surface of the pipe member 2 may be colored by an oxidizing treatment
or a plating treatment which can be carried out after or before
welding due to the laser beam. Moreover, only a portion of the peripheral
surface of the pipe member 2 which is located on the outside "O"
of the curved form and which is the non-welded part, may be colored
in order to indicate the pulling direction.
The needle member 1 and the pipe member 2 may be the same in material
as each other, or may be different in material from each other.
It is required for the needle member 1 to use material work-hardened
in order to enhance the ability of piercing into the bodily tissue.
However, the material of the pipe member 2 may have or may not have
the work-hardening ability For example, the needle member 1 employs
stainless steel of one of types SUS 302 304 and 631 which are work-hardened.
On the other hand, the pipe member 2 may use, for example, stainless
steel of type SUS 316 which is not work-hardened, in addition to
the same material as the needle member 1.
The pipe member 2 may have its outer diameter smaller than that
of the needle member 1. Moreover, such a pipe member may be employed
that an outer diameter of one end of the pipe member to be abutted
against the end face of the needle member is substantially equal
to the outer diameter of the needle member, and the other end of
the pipe member is enlarged in diameter into a trumpet form. Alternatively,
an annular step may be formed to enlarge the other end of the pipe
member. The end of the suture is inserted into the enlarged other
end of the pipe member and, subsequently, the enlarged other end
is staked. Accordingly, the other end of the pipe member is finally
brought to an outer diameter equal to or smaller than the abutting
one end of the pipe member. Prior to welding, processing or working
may be applied to the inner peripheral surface of the pipe member
to form threads or irregularities for enhancing the attaching strength
of the suture.
The pipe member having a considerable length may be welded to the
needle member. In this case, after the welding, the long pipe member
is cut at a location spaced a desired distance from the welded portion.
The laser beam may be applied to the junction between the needle
and pipe members continuously, in place of the pulses.
An electron beam may be utilized in substitution for the laser
beam. When the electron beam is employed, the beam is condensed
or concentrated by an electromagnetic lens. Moreover, it is preferable
that welding due to the electron beam is carried out in a vacuum.
The needle and pipe members may be welded to each other with a
slight gap intentionally left between them.
Prior to welding of the needle and pipe members to each other,
the needle member may beforehand be bent into a curved form. Alternatively,
a portion of the pipe member, into which the end of the suture has
been inserted, may beforehand be staked.
An apparatus suitable for carrying out the method described with
reference to FIGS. 1 through 6 and 8 will next be described with
reference to FIGS. 19 through 29.
FIG. 19 is a plan view of an apparatus 20 having a function of
supporting the needle and pipe members 1 and 2 while rotating them.
The apparatus 20 comprises a base plate 21 which is fixedly mounted
to a bed (not shown) The laser beam emitting unit shown in FIG.
1 is mounted on the bed at a location adjacent the base plate 21
that is, at an upper location as viewed in FIG. 19. The laser beam
emitting unit is designed to horizontally emit the laser beam whose
optical axis is designated by the character A in FIG. 19. As best
shown in FIG. 20 a pair of rails 22 and 22 extending parallel to
the optical axis A of the laser beam are fixedly mounted to the
upper surface of the base plate 21. A pair of sliders 23 and 23
are fixedly mounted to a lower surface of a first moving plate 24
and are fitted respectively about the rails 22 for sliding movement
therealong. Thus, the first moving plate 24 is movable in the direction
along the optical axis A of the laser beam. A rail 25 is fixedly
mounted to the upper surface of the first moving plate 24 and extends
in a direction perpendicular to the rails 22. A slider 26 is fixedly
mounted to a lower surface of a second moving plate 27 and is fitted
into the rail 25 for sliding movement therealong. Thus, the second
moving plate 27 is movable in a direction perpendicular to the optical
axis A of the laser beam.
A pair of brackets 28 and 28 are fixedly mounted to the upper surface
of the second moving plate 27. A first hollow spindle 30 is rotatably
supported by a pair of bearings 29 and 29 mounted respectively in
the brackets 28 and 28. The first spindle 30 has an axis intersected
at right angles with the optical axis A of the laser beam.
On the other hand, an upstanding bracket 31 is fixedly mounted
to the upper surface of the first moving plate 24. A pair of brackets
32 and 32 are fixedly mounted to a side face of the bracket 31.
A second hollow spindle 35 is rotatably supported by a pair of bearings
33 and 33 mounted respectively in the brackets 32 and 32. The second
spindle 35 has an axis aligned with the axis of the first spindle
30.
Confronting forward ends 30a and 35a of the respective first and
second spindles 30 and 35 are cut out such that each of the forward
ends 30a and 35a has a cross-sectional shape near a semi-circular
shape, as shown in FIGS. 23 and 24. The forward ends 30a and 35a
have their respective planar faces 30b and 35b displaced from the
axes of the respective spindles 30 and 35 and respective planar
faces 30c and 35c extending perpendicularly to the respective planar
faces 30b and 35b.
As shown in FIGS. 21 22 and 24 a first chuck mechanism 40 for
supporting the needle member 1 is mounted to the first spindle 30.
The first chuck mechanism 40 has a support member 41 which is supported
on the planar face 30b of the first spindle 30 by an L-shaped bracket
42 and which is fixed by screws 42a. The support member 41 is formed
therein with a V-shaped groove 41a shown in FIG. 24 and in FIG.
26 on an enlarged scale. The previously mentioned straight needle
member 1 can be set in the V-shaped groove 41a. With the needle
member 1 set in the V-shaped groove 41a, the axis of the needle
member 1 is aligned with the axis of the first spindle 30.
The first chuck mechanism 40 further has a retainer member 43 which
is supported on the planar face 30b of the first spindle 30 by means
of a pin 43a for pivotal movement about an axis of the pin 43a.
On the other hand, an L-shaped leaf spring 44 (see FIG. 21) is fixed
to the planar face 30c by a screw 44a. Biasing force of the leaf
spring 44 is applied to the retainer member 43 through a screw 44b
threadedly engaged with the forward end of the leaf spring 44. Thus,
the forward end 43b of the retainer member 43 can retain the needle
member 1 set in the V-shaped groove 41a.
A relatively weak auxiliary leaf spring 45 is fixed by a screw
45a to a face of the retainer member 43 on the side of the support
member 41 and can lightly retain the needle member 1 set in the
V-shaped groove 41a.
A chuck releasing pin 46 extends through the first spindle 30.
When a forward end of the chuck releasing pin 46 pushes the rearward
end 43c of the retainer member 43 the retainer member 43 is pivotally
moved about the axis of the pin 43a in the clockwise direction as
viewed in FIG. 22 so that the forward end 43b of the retainer member
43 is moved away from the needle member 1 thereby releasing the
needle member 1 from the chucked state. As shown in FIG. 19 a support
member 47 is screwed into the proximal end of the first spindle
30. The chuck releasing pin 46 slidably extends through the support
member 47 and projects therefrom outwardly.
As shown in FIGS. 21 through 23 a second chuck mechanism 50 for
supporting the pipe member 2 is mounted to the second spindle 35.
The second chuck mechanism 50 has a support member 51 which is supported
on the planar face 35b of the second spindle 35 by an L-shaped bracket
52 and which is fixed by screws 52a. The support member 51 is formed
therein with a V-shaped groove 51a shown in FIGS. 23 and 25 in
which the straight pipe member 2 can be set. With the pipe member
2 set in the V-shaped groove 51a, the axis of the pipe member 2
is aligned with the axis of the second spindle 35.
The second chuck mechanism 50 further has a retainer member 53
which is supported on the planar face 35b of the second spindle
35 by a pin 53a for pivotal movement about an axis of the pin 53a.
On the other hand, an L-shaped leaf spring 54 (see FIG. 21) is fixed
to the planar face 35c by a screw 54a. Biasing force of the leaf
spring 54 is applied to the retainer member 53 through a screw 54b
threadedly engaged with a forward end of the leaf spring 54 whereby
a face 53b of the retainer member 53 can retain the pipe member
2 set in the V-shaped groove 51a.
As shown in FIG. 20 a pusher 56 having an axis aligned with the
V-shaped groove 51a in the support member 51 extends through the
second spindle 35. A proximal end of the pusher 56 slidably extends
through a support member 57 fixed to the proximal end of the second
spindle 35 by a set screw 57a, and projects outwardly from the support
member 57. The forward end of the pusher 56 is slidably supported
by a support member 58 which is fixed to the planar face 35b of
the second spindle 35 by means of screws 58a.
As shown in FIGS. 19 and 27 a pair of brackets 60a and 60b are
fixedly mounted to the upper surface of the first moving plate 24.
A synchronous shaft 62 parallel to the spindles 30 and 35 is rotatably
supported by a pair of bearings 61 and 61 mounted respectively in
the brackets 60a and 60b. The synchronous shaft 62 has one end thereof
to which a pulley 63 is fixedly mounted by a set screw 63a. The
pulley 63 is drivingly connected to a motor M fixedly mounted to
the aforesaid bed (not shown), through a timing belt 64 and a pulley
65.
A spline 62a is formed on an axial portion of the peripheral surface
of the synchronous shaft 62 which extends over a predetermined length.
A sleeve 66 having an inner peripheral surface formed with a spline
66a is mounted on the synchronous shaft 62 for sliding movement
therealong in such a manner that the spline 66a on the sleeve 66
is in engagement with the spline 62a on the synchronous shaft 62.
A pulley 67 is fitted about the sleeve 66 and is fixed thereto by
means of a set screw 67a. The pulley 67 and the sleeve 68 are biased
by a spring 68 in the left-hand direction as viewed in FIGS. 19
and 27. A tube 69 having an end flange is fixed to an end face of
the pulley 67 on the side opposite to the spring 68. A bearing 70
is mounted about the tube 69. Movement of the pulley 67 and the
sleeve 66 to the left-hand direction is restricted by a bifurcated
fork 71 which is fixedly mounted to the second moving plate 27.
On the other hand, a third pulley 73 is mounted on a portion of
the synchronous shaft 62 which is not formed with the spline 62a.
The third pulley 73 is fixed to the synchronous shaft 62 by a set
screw 73a.
As shown in FIGS. 19 and 20 a pulley 75 is fixedly mounted to
the first spindle 30 by a set screw 75a, at a location corresponding
to the pulley 67 on the synchronous shaft 62. The pulleys 67 and
75 are connected to each other through a timing belt 76. As will
be described later, with movement of the second moving plate 27
the first spindle 30 as well as the pulley 75 move. At this time,
the fork 71 fixedly mounted to the second moving plate 27 pushes
the pulley 67 to move the same. Accordingly, the relative positional
relationship between the pulleys 67 and 75 is maintained unchanged,
making it possible to satisfactorily secure rotative transmission
through the timing belt 76.
On the other hand, a pulley 77 is fixedly mounted to the second
spindle 35 by a set screw 77a, at a location corresponding to the
pulley 73 on the synchronous shaft 62. The pulleys 73 and 77 are
connected to each other through a timing belt 78. The pulleys 67
73 75 and 77 are equal in diameter to each other. Accordingly,
when the synchronous shaft 62 is rotated by the motor M, the first
and second spindles 30 and 35 are rotated at the same rotational
speed while the relative angular positional relationship between
the first and second spindles 30 and 35 is maintained unchanged.
As shown in FIGS. 19 and 28 a sleeve 80a is fixedly mounted to
the aforesaid bracket 60a. A bracket 81 is fixedly mounted to the
first moving plate 24 at a location spaced away from the bracket
60a in the direction perpendicular to the optical axis A of the
laser beam. Another sleeve 80b is fixedly mounted to the bracket
81. A pair of center shafts 82a and 82b are supported respectively
by the sleeves 80a and 80b for sliding movement therealong such
that axes of the respective center shafts 82a and 82b are aligned
with each other. The center shafts 82a and 82b have their respective
pointed ends, and are biased toward each other respectively by springs
83a and 83b. A positioning shaft 84 is supported between and by
the pointed ends of the respective center shafts 82a and 82b for
angular movement about an axis of the positioning shaft 84. An operating
lever 85 is mounted on the shaft 84 for angular movement therewith.
A positioning lever 86 is also mounted on the shaft 84 for angular
movement therewith. In FIG. 28 the positioning lever 86 and the
operating lever 85 are shown as having their respective attaching
angles equal to each other, in order to facilitate understanding
of the construction. In practice, however, the positioning lever
86 and the operating lever 85 are angularly displaced in attaching
angle from each other by 90 degrees, as shown in FIG. 19. A cam
follower 87 is rotatably mounted on the shaft 84. On the other hand,
a bracket 88 is fixedly mounted to the first moving plate 24. A
face cam 89 is fixed to the bracket 88 by a set screw 89a. The shaft
84 extends through the center of the face cam 89. The cam follower
87 is abutted against a cam face of the face cam 89.
Normally, as shown in FIG. 19 the positioning lever 86 is in a
vertically upstanding position, while the operating lever 85 is
in a horizontal position. When the operating lever 85 is angularly
moved about the axis of the shaft 84 by 90 degrees to a vertically
upstanding position, the positioning lever 86 is angularly moved
to a horizontal position facing toward the spindles 30 and 35. During
this angular movement, the cam action between the face cam 89 and
the cam follower 87 causes the positioning lever 86 to be moved
in the left-hand direction as viewed in FIGS. 19 and 28 while the
positioning lever 86 is angularly moved such that a positioning
face 86a at the forward end of the positioning lever 86 approaches
the forward end of the second spindle 35. Finally, the positioning
face 86a is brought to a position coincident with a vertical plane
including the optical axis A of the laser beam.
As shown in FIG. 19 a pair of brackets 90a and 90b are fixedly
mounted to the base plate 21. A cam shaft 92 is rotatably supported
by a pair of bearings 91 and 91 mounted respectively in the brackets
90a and 90b. The cam shaft 92 has one end thereof to which a pulley
93 is fixedly mounted. The pulley 93 is drivingly connected to the
motor M (see FIG. 27) through a timing belt and a pulley (both not
shown).
The pulley 93 on the cam shaft 92 which is drivingly connected
to the motor M, has a diameter five times that of the pulley 63
on the aforementioned cam shaft 62. With such arrangement, the cam
shaft 92 makes one revolution while the synchronous shaft 62 makes
five revolutions. The cam shaft 92 serves as a driving source for
a first moving mechanism 100 for moving the first moving plate 24
a second moving mechanism 110 for moving the second moving plate
27 and a third moving mechanism 120 for moving the aforesaid chuck
releasing pin 46.
The first moving mechanism 100 will be described with reference
to FIG. 19. A plate cam 101 is fixedly mounted to the cam shaft
92. On the other hand, a bracket 102 is fixedly mounted to the lower
surface of the base plate 21. An auxiliary shaft 104 is rotatably
supported by a pair of bearings 103 which are mounted respectively
in the bracket 102 and the aforesaid bracket 90b.
An elongated link 105 has one end thereof fixedly mounted to the
auxiliary shaft 104 and extends therefrom vertically upwardly.
A cam follower 106 is supported at a longitudinally intermediate
portion of the link 105. A threaded shaft 107b has one end thereof
fixed to the other upper end of the link 105. A link 90c is fixedly
mounted to the bracket 90b, and extends therefrom vertically upwardly.
A threaded shaft 107a has one end thereof fixed to the upper end
of the link 90c. A coil spring 107 is interposed under tension between
the pair of threaded shafts 107a and 107b to bring the cam follower
106 into contact with the circumferential surface of the plate cam
101.
A link 108 has one end thereof fixedly mounted to the auxiliary
shaft 104 and extends therefrom vertically upwardly. The link 108
is formed with a cam face 108a extending vertically. On the other
hand, a bracket 109 is fixedly mounted to the lower surface of the
first moving plate 24. A cam follower 109a is rotatably supported
at the forward end of the bracket 109. The first moving plate 24
is biased upwardly as viewed in FIG. 19 by a spring (not shown)
The spring brings the cam follower 109a into contact with the cam
face 108a on the link 108.
In the above-described first moving mechanism 100 during one revolution
of the cam shaft 92 the cam action between the plate cam 101 and
the cam follower 106 causes the auxiliary shaft 104 to be angularly
moved about its own axis in a reciprocative manner within a predetermined
angular extent. By this reciprocative angular movement, the cam
action between the cam face 108a and the cam follower 109a causes
the first moving plate 24 to be once reciprocated along the optical
axis A of the laser beam. The timing of this reciprocative movement
will be described later.
The second moving mechanism 110 will next be described with reference
to FIGS. 19 and 29. A plate cam 111 is fixedly mounted to the cam
shaft 92. On the other hand, an auxiliary shaft 112 is fixedly mounted,
in a cantilevered fashion, to the bracket 90a fixed to the lower
surface of the base plate 21. A link 113 has one end thereof mounted
on the auxiliary shaft 112 for pivotal movement about an axis thereof,
and extends vertically upwardly from the auxiliary shaft 112. A
cam follower 113a is rotatably supported at a longitudinally intermediate
portion of the link 113. Another link 114 is fixedly mounted to
the bracket 90a, and extends therefrom vertically upwardly. A threaded
shaft 104a has one end fixed to the upper end of the link 114 and
extends therefrom horizontally. A coil spring 115 is interposed
under tension between the shaft 114a and the other upper end of
the link 113 to bring the cam follower 113a into contact with the
peripheral surface of the plate cam 111. The link 113 is formed
therein with a slot 113b extending vertically. A slider 116a mounted
to one end of a rod 116 is slidably fitted into the slot 113b. The
other end of the rod 116 is connected at right angles to one end
of another rod 117. The other end of the rod 117 is connected to
one end of a bell crank 118 which is pivotally movable about an
axis of a pivot 118a. A cam follower 119 is rotatably mounted to
the other end of the bell crank 118. On the other hand, the second
moving plate 27 is biased to the left-hand direction as viewed in
FIG. 19 by a spring (not shown), to bring the side face of the second
moving plate 27 into contact with the cam follower 119.
In the above-described second moving mechanism 110 when the cam
shaft 92 makes one revolution, the cam action between the plate
cam 111 and the cam follower 113a causes the link 113 to be once
reciprocated angularly within a predetermined angular extent about
the axis of the auxiliary shaft 112. The reciprocative movement
is transmitted to the bell crank 118 through the rods 116 and 117
so that the bell crank 118 is angularly moved reciprocatively about
the axis of the pivot 118a. The reciprocative angular movement of
the bell crank 118 is transmitted to the second moving plate 27
through the cam follower 119 so that the second moving plate 27
is moved reciprocatively in the direction perpendicular to the optical
axis A of the laser beam. The timing of this reciprocative movement
will be described later.
The third moving mechanism 120 has a cam structure similar to the
second moving mechanism 110. The third moving mechanism 120 will
be described below with reference to FIG. 19. A plate cam 121 is
fixedly mounted to the cam shaft 92. On the other hand, a link 123
has one end thereof pivotally mounted on the aforementioned auxiliary
shaft 112 and extends therefrom vertically upwardly. A cam follower
123a is rotatably supported at a longitudinally intermediate portion
of the link 123. A spring 125 is interposed under tension between
the aforesaid threaded shaft 114a and the other upper end of the
link 123 to bring the cam follower 123a into contact with the peripheral
surface of the plate cam 121. The link 123 is formed therein with
a slot (not shown) extending vertically. A slider (not shown) mounted
to one end of a rod 126 is slidably fitted into the slot. The other
end of the rod 126 is connected to one end of a bell crank 128 which
is pivotally movable about an axis of a pivot 128a. A link 129 has
one end thereof which is pivotally mounted to the other end of the
bell crank 128. The other end of the link 129 is pivotally connected
to the aforesaid chuck releasing pin 46.
In the above-described third moving mechanism 120 when the cam
shaft 92 makes one revolution, the cam action between the cam plate
121 and the cam follower 123a causes the link 123 to be once reciprocated
angularly within a predetermined angular extent about the axis of
the auxiliary shaft 112. This angular reciprocative movement of
the link 123 is transmitted to the bell crank 128 through the rod
126 so that the bell crank 128 is reciprocated angularly within
a predetermined angular extent about the axis of the pivot 128a.
As a result, the chuck releasing pin 46 is once reciprocatively
moved along its own axis. The timing of this reciprocative movement
will be described later
In the state prior to the start-up of operation of the apparatus
constructed as above, the first spindle 30 is in a position spaced
away from the second spindle 35. Moreover, the spindles 30 and 35
are in their respective angular positions where the V-shaped grooves
41a and 51a in the respective support members 41 and 51 are directed
vertically upwardly. Further, the chuck releasing pin 46 is in an
ejected position, and the forward end 43b of the retainer member
43 is in a position spaced away from the support member 41.
In the state described above, an operator lifts the retainer member
53 up against the biasing force of the leaf spring 54 of the chuck
mechanism 50. With the retainer member 53 lifted up, the operator
then sets the pipe member 2 into the V-shaped groove 51a in the
support member 51. Subsequently, the operator releases his hold
from the retainer member 53 to cause the same to retain the pipe
member 2 under the biasing force of the leaf spring 54.
Then, the operator turns the operating lever 85 about the axis
of the positioning shaft 84 to bring the positioning lever 86 to
a position in the vicinity of the forward end of the support member
51 of the chuck mechanism 50. Subsequently, the operator pushes
the pusher 56 to bring the end face of the pipe member 2 into abutment
against the positioning lever 86. As a result, the pipe member 2
is set at such a position that the one end of the pipe member 2
protrudes a predetermined length from the forward end of the support
member 51 and the end face of the one end of the pipe member 2
is coincident with the vertical plane including the optical axis
A of the laser beam.
Subsequently, the operator turns the operating lever 85 about the
axis of the positioning shaft 84 to return the positioning lever
86 to its initial upstanding position. The operator then lifts the
auxiliary leaf spring 45 up, and sets the needle member 1 into the
V-shaped groove 41a formed in the support member 41 of the chuck
mechanism 40. Subsequently, the operator releases his hold from
the auxiliary leaf spring 45 to cause the same to lightly retain
the needle member 1 under the biasing force of the leaf spring 45.
At this time, the end face 1a of the needle member 1 is located
adjacent the end face 2a of the pipe member 2 so that the end of
the needle member 1 projects greatly from the forward end of the
support member 41 which is in its retracted position.
After the pipe and needle members 2 and 1 have been set in the
manner as described above, the motor M is driven. The motor M is
stopped after the synchronous shaft 62 makes five revolutions and
the cam shaft 92 makes one revolution.
The action during a period for which the synchronous shaft 62 makes
first one-fourth revolution, will first be described. By the action
of the second moving mechanism 110 the second moving plate 27 is
moved in the left-hand direction as viewed in FIG. 19 so that the
first spindle 30 and the chuck mechanism 40 are moved in the same
left-hand direction. Before the synchronous shaft 62 reaches the
rotational angle of the one-fourth revolution, the forward end of
the support member 41 of the chuck mechanism 40 reaches a position
in the vicinity of the forward end of the support member 51 of the
chuck mechanism 50. At this time, the second moving plate 27 is
stopped. In the course of this movement, the end face 1a of the
needle member 1 is abutted against the end face 2a of the needle
member 2 so that the needle member 1 is positioned. On and after
this, with movement of the chuck mechanism 40 the needle member
1 slidingly moves relatively to the auxiliary leaf spring 45 and
the V-shaped groove 41a. In the latter half of the first one-fourth
revolution of the synchronous shaft 62 the third moving mechanism
120 causes the chuck releasing pin 46 to be moved rearwardly. After
the second moving plate 27 is stopped, the needle member 1 is retained
by the retainer member 43 which is biased by the strong leaf spring
44. Thus, the needle and pipe members 1 and 2 are chucked in such
a manner that the end faces 1a and 2a of the respective needle and
pipe members 1 and 2 are abutted against each other in the vertical
plane including the optical axis A of the laser beam. In this chucked
state, the peripheral surfaces of the respective needle and pipe
members 1 and 2 are located adjacent the focal position of the laser
beam.
During the subsequent one and one-fourth revolutions of the synchronous
shaft 62 the laser beam emitting unit 10 (see FIG. 1) outputs pulses
of the laser beam. Welding is carried out in such a manner that
the pulses of the laser beam are applied to the junction between
the needle and pipe members 1 and 2 along the abutting line 3 in
a partially overlapped fashion as shown in FIG. 6.
During the subsequent one-fourth revolution of the synchronous
shaft 62 the first moving mechanism 100 causes the first moving
plate 24 to be moved downwardly as viewed in FIG. 19. Thus, the
needle and pipe members 1 and 2 are moved in the direction along
the optical axis A of the laser beam, that is, in the direction
perpendicular to the aligned axes of the respective needle and pipe
members 1 and 2 while the abutting line 3 is maintained coincident
with the optical axis A of the laser beam.
Subsequently, the pulses of the laser beam or the continuous laser
beam is emitted from the emitting unit 10 while the synchronous
shaft 62 makes one revolution. The above-mentioned movement of the
first moving plate 24 causes the peripheral surfaces of the respective
needle and pipe members 1 and 2 to be moved away from the focal
position of the laser beam as shown in FIG. 8 so that the spot
diameter of the laser beam on the peripheral surfaces of the respective
needle and pipe members 1 and 2 increases. Accordingly, annealing
is carried out along the welded portion over the width wider than
the welded portion and at the temperature lower than the melting
temperature.
In the course of the subsequent two revolutions of the synchronous
shaft 62 the second moving plate 27 is moved in the right-hand
direction as viewed in FIG. 19 by the second moving mechanism 110
and is returned to the initial position. Since the biasing force
of the leaf spring 44 of the chuck mechanism 40 is considerably
stronger than that of the leaf spring 54 of the chuck mechanism
50 the pipe member 2 welded to the needle member 1 is moved together
with the same in the right-hand direction as viewed in FIG. 19
and is drawn out of the chuck mechanism 50. Since, during this movement
of the pipe member 2 the laser beam is maintained outputted, the
peripheral surface of the pipe member 2 is annealed in a helical
fashion. As a consequence, the entire peripheral surface of the
pipe member 2 is annealed.
In the course of the subsequent last one-fourth revolution of the
synchronous shaft 62 the third moving mechanism 120 causes the
chuck releasing pin 46 to be moved forwardly, that is, in the left-hand
direction as viewed in FIG. 19 so that the needle member 1 is released
from the chucked state due to the biasing force of the strong leaf
spring 44 and is retained only by the auxiliary spring 45. Moreover,
in the course of the last one-fourth revolution of the synchronous
shaft 62 the first moving mechanism 100 causes the first moving
plate 24 to be moved upwardly as viewed in FIG. 19 and to be returned
to the initial position.
FIGS. 30 and 31 show another embodiment of the invention, which
comprises different arrangement for rotating the needle and pipe
members about their respective axes. In the arrangement illustrated
in FIGS. 30 and 31 a bracket 200 is fixedly mounted to a moving
plate (not shown). A spindle 202 is rotatably supported by a pair
of bearings 201 and 201 mounted in the bracket 200. A pulley 203
is fixedly mounted to the proximal end of the spindle 202 and is
connected to the pulley fixedly mounted to an output shaft of a
motor (not shown) through the timing belt. A pair of chuck mechanisms
for chucking respectively the needle and pipe members are mounted
to the forward end of the spindle 202. Each of these chuck mechanisms
is similar in construction to the chuck mechanism 50 for the pipe
member in the above-mentioned embodiment illustrated in FIGS. 21
through 23 and the detailed description and illustration of the
chuck mechanisms will therefore be omitted. In FIGS. 30 and 31
only support members 205 and 206 of the respective chuck mechanisms
are shown. A forward end of the spindle 202 is cut out to form a
planar face 202a extending parallel to the axis of the spindle 202.
The support members 205 and 206 are fixedly mounted to the planar
face 202a, and are spaced a slight distance from each other. V-shaped
grooves 205a and 206a formed respectively in the support members
205 and 206 are located in alignment with each other, so that the
axes of the respective needle and pipe members set respectively
in the V-shaped grooves 205a and 206a are aligned with the axis
of the spindle 202. The forward end portion of the spindle 202 is
formed therein with a plurality of bores 202b at a position corresponding
to the gap between the support members 205 and 206. As best shown
in FIG. 31 the bores 202b extend radially outwardly from the axis
of the spindle 202.
In the arrangement illustrated in FIGS. 30 and 31 the forward
end of the positioning lever (86: see FIG. 19) is moved to a position
between the support members 205 and 206 and the end face of the
needle member is abutted against the positioning lever and is positioned
thereby. In this manner, the needle member is set in the V-shaped
groove 205a formed in the support member 205 and is retained by
the retainer member biased by the leaf spring (not shown). Then,
the positioning lever is moved away from the gap between the support
members 205 and 206 and, subsequently, the end face of the pipe
member is abutted against the end face of the needle member to position
the pipe member. In this manner, the pipe member is set in the V-shaped
groove 206a formed in the support member 206 and is retained by
the retainer member biased by the leaf spring (not shown). Then,
while rotating the spindle 202 about its own axis, the pulses of
the laser beam from the laser beam emitting unit (not shown) are
applied to the junction between the needle and pipe members along
the abutting line, to thereby carry out welding.
During application of the pulses of the laser beam, the forward
end portion of the spindle 202 intercepts the optical axis of the
laser beam within a predetermined angular extent. Since, however,
the bores 202b are formed in the forward end portion of the spindle
202 the pulses of the laser beam can be applied to the junction
between the needle and pipe members, with the result that welding
can be carried out substantially along the entire circumferential
length of the abutting line. The laser beam emitting unit is controlled
in such a synchronous manner that the pulses of the laser beam are
successively emitted each time the bores 202b are successively aligned
with the optical axis of the laser beam. If it is desired to partially
weld the junction between the needle and pipe members only at, for
example, two locations, not along the entire circumferential length
of the abutting line, the bores 202b are unnecessary and are dispensed
with. After the welding, the moving plate supporting the spindle
202 is moved in the direction along the optical axis of the laser
beam in a manner similar to that of the previously mentioned embodiment.
Subsequently, the laser beam is applied to the welded portion while
rotating the spindle 202 about its own axis, thereby carrying out
annealing.
The arrangement of the embodiment illustrated in FIGS. 30 and 31
is such that the needle and pipe members are supported by the single
spindle 202 and are rotated thereby. Accordingly, as compared with
the arrangement in which, as is in the previous embodiment, the
needle and the pipe members are supported respectively by the spindles
30 and 35 independent of each other and are rotated respectively
thereby, it is possible for the arrangement illustrated in FIGS.
30 and 31 to dispense with the mechanism for synchronism such as,
for example, the synchronous shaft 62 and the associated components.
It is needless to say that the arrangement illustrated in FIGS.
30 and 31 can be applied to the method in which welding is carried
out only at a plurality of locations on the abutting line, like
the previous embodiment shown in FIGS. 19 through 29.
FIGS. 32 and 33 show still another embodiment of the invention,
in which while the needle and pipe members are maintained stationary,
the laser beam emitting unit moves around the aligned axes of the
respective needle and pipe members. Specifically, a casing 300 has
a top wall formed therein with an opening 300a. A pair of support
members 301 and 302 are fixedly mounted to an upper surface of the
top wall of the casing 300. The support members 301 and 302 have
their respective upper surfaces which are formed respectively with
V-shaped grooves 301a and 302a aligned with each other. The needle
and pipe members can be set respectively in the V-shaped grooves
301a and 302a. Positioning and chucking of these needle and pipe
members are similar to those in the previous embodiment described
with reference to FIGS. 19 through 29 and the description of the
positioning and chucking will therefore be omitted. A ring-like
rail 304 is fixedly mounted to the casing 300 through a bracket
303. A plurality of circumferentially spaced sliders 306 are fixed
to the ring-like support member 305 and are supported by the rail
304 through respective bearings or the like (not shown). The support
member 305 has a peripheral surface formed with teeth 305a. A gear
306a fixedly mounted to the output shaft of the motor M is in mesh
with the teeth 305a of the support member 305. Accordingly, rotation
of the motor M causes the support member 305 to be rotated. A center
of rotation of the support member 305 in other words, a center
of the radius of curvature of the support member 305 is coincident
with the aligned axes of the respective needle and pipe members
set respectively in the V-shaped grooves 301a and 302a formed in
the respective support members 301 and 302.
On the other hand, a collimated laser beam is outputted from a
laser beam generating source 310 mounted stationarily, toward a
laser beam dividing unit 311 mounted stationarily. The laser beam
dividing unit 311 comprises a semi-transparent mirror 312 and a
mirror 313 and a pair of condenser optical systems 314 and 315
including their respective convex lenses optically connected respectively
to the mirrors 312 and 313. Only half the collimated laser beam
generated at the laser beam generating source 310 is reflected by
the semi-transparent mirror 312 and is directed toward the condenser
optical system 314. The laser beam is condensed by the condenser
optical system 314 and is supplied to one end of an optical fiber
316. The remaining half of the collimated laser beam transmitted
through the semi-transparent mirror 312 is reflected by the mirror
313 and is directed to the second condenser optical system 315.
The laser beam from the mirror 313 is condensed by the condenser
optical system 315 and is supplied to one end of a second optical
fiber 317. The other ends of the respective optical fibers 316 and
317 are connected respectively to a pair of laser beam emitting
sections 320 and 320. The pair of laser beam emitting sections 320
and 320 are circumferentially spaced 180 degrees from each other
so that they face each other. Each laser beam emitting section 320
comprises a casing 321 fixedly mounted to the support member 305
and a condenser optical system 322 including a convex lens fixed
to the casing 321. The other ends of the respective optical fibers
316 and 317 extend through the rear walls of the respective casings
321 and face the respective condenser optical systems 322 and 322
to supply the laser beams thereto. Each condenser optical system
322 condenses the corresponding laser beam to supply the same onto
the abutting line between the needle and pipe members. Each laser
beam has an optical axis intersected with the aligned axes of the
respective needle and pipe members.
The arrangement of the embodiment illustrated in FIGS. 32 and 33
is such that while angularly moving the support member 305 by the
motor M about the aligned axes of the respective needle and pipe
members, the respective laser beams from the pair of facing laser
beam emitting sections 320 and 320 are simultaneously supplied onto
the abutting line. With such arrangement, if it is desired to weld
the needle and pipe members to each other along the entire circumferential
length of the abutting line, it is sufficient to angularly move
the support member 305 substantially through 180 degrees or through
an angular extent slightly larger than 180 degrees.
Three or more laser beam emitting sections may be mounted to the
support member 305. In this case, if it is desired to carry out
welding along the entire circumferential length of the abutting
line, it is possible to further narrow the angular extent through
which the support member 305 is angularly moved. Moreover, only
a single laser beam emitting section may be mounted to the support
member 305.
When it is desired to carry out welding only at a plurality of
locations spaced from each other along the abutting line, it is
not required for the support member to be angularly moved about
the aligned axes of the respective needle and pipe members, but
the support member may be fixed to the casing, if a plurality of
laser beam emitting sections corresponding in number to the locations
to be welded are mounted to the support member. |