Suture needle abstract
For annealing a proximal end portion of a needle material for a
suture needle, an energy beam is applied to a proximal end face
of the needle material. There can be used a common oscillator which
emits a laser beam for forming a gut-mounting hole in the proximal
end portion of the needle material, and also emits a laser beam
for effecting the above annealing. In this case, a converter is
used for changing a path of travel of the laser beam. Namely, for
forming the mounting hole, the laser beam from the oscillator is
supplied to the proximal end face of the needle material through
a condenser lens. For effecting the annealing, the laser beam is
smoothed by a smoothing member, and is applied to the proximal end
face of the needle material. In the case where the common oscillator
is used, the needle material may be moved along the axis of the
needle material.
Suture needle claims
What is claimed is:
1. A method of manufacturing an eyeless suture needle, comprising
the steps of:
(a) forming a mounting hole in a proximal end face of a needle
material in such a manner that said mounting hole extends along
an axis of said needle material, a gut being adapted to be inserted
into and fixed to said mounting hole; and
(b) applying an energy beam to the proximal end face of said needle
material to anneal a proximal end portion of said needle material.
2. A method according to claim 1 in which the axis of said energy
beam applied to said needle material is in alignment with the axis
of said needle material.
3. A method according to claim 2 in which an area of irradiation
of said energy beam at the proximal end face of said needle material
is substantially equal to the area of said proximal end face.
4. A method according to claim 1 in which said step (b) comprising
applying a plurality of energy beams to said needle material in
such a manner that the axis of each of said plurality of energy
beams is inclined relative to the axis of said needle material,
the axes of said plurality of energy beams being spaced from one
another in a direction of the periphery of said needle material,
and said plurality of energy beams being applied not only to the
proximal end face of said needle material but also to an outer peripheral
surface of the proximal end portion of said needle material.
5. A method according to claim 4 in which the axes of said plurality
of energy beams are inclined at the same angle relative to the axis
of said needle material, and are spaced at equal intervals from
one another in the direction of the periphery of said needle material.
6. A method according to claim 5 in which the angle of inclination
of the axis of each of said energy beams relative to the axis of
said needle material is in the range of between 20.degree. to 60.degree..
7. A method according to claim 1 in which said annealing is carried
out in an atmosphere of inert gas.
8. A method according to claim 1 in which the formation of said
mounting hole is carried out by concentrating another energy beam
on the center of the proximal end face of said needle material,
the axis of said another energy beam being in alignment with the
axis of said needle material, and said annealing being carried out
after the formation of said mounting hole.
9. Apparatus for manufacturing an eyeless suture needle comprising:
(a) emitting means for emitting a pulsed laser beam of parallel
rays;
(b) support means for supporting a needle material in such a manner
that the axis of said needle material is in alignment with the optical
axis of said laser beam;
(c) condenser means for condensing said laser beam, said condenser
means being disposed in the vicinity of a proximal end face of said
needle material, supported by said support means, in such a manner
that an axis of said condenser means is in alignment with the optical
axis of said laser beam;
(d) smoothing means for smoothing said pulsed laser beam, said
smoothing means being spaced from the optical axis of said laser
beam;
(e) switching means disposed between said emitting means and said
condenser means so as to switch a path of travel of said laser beam
between a first light path and a second light path, said switching
means first selecting said first light path and then selecting said
second light path; when said laser beam from said emitting means
travels along said first light path, said laser beam passing past
said switching means to reach said condenser means, so that said
laser beam condensed by said condenser means is applied to the center
of the proximal end face of said needle material to thereby form
a mounting hole in said proximal end face, a gut being adapted to
be inserted into and fixed to said mounting hole; and when said
laser beam from said emitting means travels along said second light
path, said laser beam passing through said smoothing means to be
smoothed and further passing through said condenser means to be
applied to the proximal end face of said needle material to thereby
anneal said needle material.
10. Apparatus according to claim 9 in which said switching means
comprises a pair of first and second mirrors each pivotal between
an operative position and an inoperative position, said first mirror
being disposed close to said emitting means whereas said second
mirror is disposed remote from said emitting means; when said first
light path is selected, each of said first and second mirrors being
disposed in said inoperative position where said mirror is displaced
from the optical axis of said laser beam from said emitting means;
and when said second light path is selected, each of said first
and second mirrors being disposed in said operative position where
said mirror is disposed on the optical axis of said laser beam from
said emitting means, so that said first mirror reflects said laser
beam from said emitting means to direct said laser beam to said
smoothing means whereas said second mirror reflects said laser beam
passing through said smoothing means to direct said laser beam to
said condenser means.
11. Apparatus according to claim 10 in which said smoothing means
comprises a fiber of the graded index type having a core, a condenser
lens being disposed between one end of said fiber and said first
mirror so as to direct said laser beam, reflected by said first
mirror, to said core of said fiber, and a collimator lens being
disposed between the other end of said fiber and said second mirror
so as to bring said laser beam, going out of said core, into a beam
of parallel rays.
12. Apparatus according to claim 11 further comprising moving
means for moving said support means along the axis of said needle
material between a first position and a second position, said support
means being first disposed in said first position when said mounting
hole is to be formed, and then being disposed in said second position
when said annealing is to be effected, and the proximal end face
of said needle material being remoter from the focus of said condenser
means in said second position than in said first position.
13. Apparatus for manufacturing an eyeless suture needle comprising:
(a) emitting means for emitting a pulsed laser beam of parallel
rays;
(b) support means for supporting a needle material in such a manner
that the axis of said needle material is in alignment with the optical
axis of said laser beam;
(c) condenser means for condensing said laser beam, said condenser
means being disposed in the vicinity of a proximal end face of said
needle material, supported by said support means, in such a manner
that an axis of said condenser means is in alignment with the optical
axis of said laser beam; and
(d) moving means for moving said support means along the axis of
said needle material between a first position and a second position,
said support means being first disposed in said first position,
and then being disposed in said second position; in said first position,
said laser beam from said emitting means being condensed by said
condenser means to be applied to the center of the proximal end
face of said needle material to thereby form a mounting hole in
said proximal end face, a gut being adapted to be inserted into
and fixed to said mounting hole, and the proximal end face of said
needle material being remoter from the focus of said condenser means
in said second position than in said first position, so that said
laser beams from said condenser means is spreaded over the proximal
end face of said needle material to thereby anneal a proximal end
portion of said needle material.
Suture needle description
BACKGROUND OF THE INVENTION
This invention relates to a method of and apparatus for manufacturing
an eyeless suture needle.
Instead of martensite-type stainless steel, austenite-type stainless
steel has increasingly been used as a needle material for eyeless
suture needles. Examples of such austenite-type stainless steel
includes SUS304 SUS302 and SUS63151. Unlike martensite-type stainless
steel, austenite-type stainless steel can not be hardened by quench
hardening, and is usually hardened by work-hardening. Therefore,
a wire material is cold-drawn and is hardened, and then is cut to
produce needle materials. Subsequent steps are to point a distal
end of the needle material, to form a mounting hole in a proximal
end portion of the needle material, to insert a gut into the mounting
hole and then to deform the proximal end portion of the needle material
under pressure to fixedly secure the gut to the needle material,
and to bend the needle material.
In order to deform the proximal end portion of the needle material
to secure the gut to the needle material, the proximal end portion
of the needle material is required to have a low hardness. If the
hardness of the proximal end portion is high, the deformation of
the proximal end portion can not be carried out satisfactorily.
This may result in an unsatisfactory fixing of the gut to the needle
material, and also may result in a situation in which part of the
deformed proximal end portion is projected outwardly of the outer
peripheral surface of the remainder, thereby adversely affecting
the ability of the resultant suture needle to penetrate.
The needle material made of the austenite-type stainless steel
is obliged to have a high hardness at the first stage as described
above, and therefore it is necessary to sufficiently lower the hardness
of the proximal end portion of the needle material by changing the
crystals of the proximal end portion from a fiber-like elongated
shape into a grain (particle)-like shape by means of annealing of
the proximal end portion.
Japanese Utility Model Publication No. 25219/85 discloses a method
in which an energy beam is applied to a needle material with its
optical axis aligned with the axis of the needle material, thereby
forming a mounting hole in the needle material, and thereafter a
proximal end portion of the needle material is annealed using a
burner. More specifically, a flame of the burner is applied to the
outer peripheral surface of the proximal end portion of the needle
material in a direction perpendicular or oblique to the axis of
the needle material.
With this conventional method, however, the flame of the burner
is unstable, and therefore there is a possibility that a very hard
portion may remain at the proximal end portion of the needle material,
in which case the proximal end portion can not be satisfactorily
deformed under pressure. In order to avoid such disadvantage to
sufficiently lower the hardness of the proximal end portion of the
need material, the flame must be excessively applied to the outer
peripheral surface of the proximal end portion of the needle material.
As a result, the outer peripheral surface of the proximal end portion
is roughened because of a local fusion thereof, and an oxide film
is formed on this outer peripheral surface. Therefore, the needle
material must be subjected to electropolishing for a long time,
which results in a problem that the pointed distal end becomes dull,
thus adversely affecting the penetrating ability of the needle.
Another problem of this conventional method is that the hardness
of the needle material may be lowered over a region or length generally
equal to or greater than the depth of the mounting hole. In other
words, the portion of low hardness becomes excessively longer. This
results in decrease of the strength of the proximal end portion
of the needle material.
Japanese Patent Publication No. 55410/88 also discloses a method
in which a flame of a burner is applied to a proximal end portion
of a needle material in a direction perpendicular to the axis of
the needle material, thereby annealing this proximal end portion.
U.S. Pat. No. 4910377 discloses a technique in which a mounting
hole is formed in a proximal end portion of a needle material by
an energy beam such as a laser beam and an electron beam.
Japanese Laid-Open (Kokai) Utility Model Application No. 43691/80
and Japanese Laid-Open Patent Application No. 184485/85 disclose
a technique in which when forming a mounting hole in a proximal
end portion of a needle material, the focus of a condenser lens
is spaced or displaced from the proximal end portion of the needle
material.
Japanese Laid-Open Patent Application No. 110532/84 discloses a
device for supporting needle materials. This device comprises a
rotary disk having V-shaped grooves, and a holder member.
U.S. Pat. No. 4935029 discloses a technique in which a needle
material and a pipe material are welded together by an energy beam,
and subsequently the welded portion, as well as the pipe material
if necessary, is annealed by an energy beam. In this annealing method,
however, the energy beam is applied in a direction perpendicular
to the axis of the needle material, and the needle material is not
only moved in its axial direction but also is rotated. In this method,
the time required for the annealing is very long.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a method of manufacturing
a suture needle in which an ideal hardness distribution of a proximal
end portion of a needle material can be achieved in a relatively
short time by annealing, and the outer peripheral surface of the
proximal end portion of the needle material is not unduly roughened.
Another object of the invention is to provide apparatus for performing
such method.
According to one aspect of the present invention, there is provided
a method of manufacturing an eyeless suture needle, comprising the
steps of:
(a) forming a mounting hole in a proximal end face of a needle
material in such a manner that the mounting hole extends along an
axis of the needle material, a gut being adapted to be inserted
into and fixed to the mounting hole; and
(b) applying an energy beam to the proximal end face of the needle
material to anneal a proximal end portion of the needle material.
According to another aspect of the invention, there is provided
apparatus for manufacturing an eyeless suture needle comprising:
(a) emitting means for emitting a pulsed laser beam of parallel
rays;
(b) support means for supporting a needle material in such a manner
that the axis of the needle material is in alignment with the optical
axis of the laser beam;
(c) condenser means for condensing the laser beam, the condenser
means being disposed in the vicinity of a proximal end face of the
needle material, supported by the support means, in such a manner
that an axis of the condenser means is in alignment with the optical
axis of the laser beam;
(d) smoothing means for smoothing the pulsed laser beam, the smoothing
means being spaced from the optical axis of the laser beam;
(e) switching means disposed between the emitting means and the
condenser means so as to switch a path of travel of the laser beam
between a first light path and a second light path, the switching
means first selecting the first light path and then selecting the
second light path; when the laser beam from the emitting means travels
along the first light path, the laser beam passing past the switching
means to reach the condenser means, so that the laser beam condensed
by the condenser means is applied to the center of the proximal
end face of the needle material to thereby form a mounting hole
in the proximal end face, a gut being adapted to be inserted into
and fixed to the mounting hole; and when the laser beam from the
emitting means travels along the second light path, the laser beam
passing through the smoothing means to be smoothed and further passing
through the condenser means to be applied to the proximal end face
of the needle material to thereby anneal the needle material.
According to a further aspect of the invention, there is provided
apparatus for manufacturing an eyeless suture needle comprising:
(a) emitting means for emitting a pulsed laser beam of parallel
rays;
(b) support means for supporting a needle material in such a manner
that the axis of the needle material is in alignment with the optical
axis of the laser beam;
(c) condenser means for condensing the laser beam, the condenser
means being disposed in the vicinity of a proximal end face of the
needle material, supported by the support means, in such a manner
that an axis of the condenser means is in alignment with the optical
axis of the laser beam; and
(d) moving means for moving the support means along the axis of
the needle material between a first position and a second position,
the support means being first disposed in the first position, and
then being disposed in the second position; in the first position,
the laser beam from the emitting means being condensed by the condenser
means to be applied to the center of the proximal end face of the
needle material to thereby form a mounting hole in the proximal
end face, a gut being adapted to be inserted into and fixed to the
mounting hole, and the proximal end face of the needle material
being remoter from the focus of the condenser means in the second
position than in the first position, so that the laser beams from
the condenser means is spreaded over the proximal end face of the
needle material to thereby anneal a proximal end portion of the
needle material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a needle manufacturing apparatus
according to the present invention;
FIG. 2 is a graph showing a distribution of thermal energy applied
to a needle material when annealing it;
FIG. 3 is a graph showing a distribution of the hardness of the
needle material after the annealing;
FIG. 4 is an enlarged, partly cross-sectional, side-elevational
view of a proximal end portion of the needle material after the
formation of a mounting hole;
FIG. 5 is a view similar to FIG. 4 but showing a condition after
the annealing;
FIG. 6 is an enlarged, side-elevational view of the proximal end
portion of the needle material after a gut is secured thereto;
FIGS. 7 and 8 are schematic views showing modified apparatuses,
respectively;
FIG. 9 is a schematic view of a further modified apparatus shown
in its mounting hole-forming mode; and
FIG. 10 is a view similar to FIG. 9 but showing an annealing mode.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
A preferred embodiment of the invention will now be described with
reference to the drawings. Reference is first made to a needle material
100 for an eyeless suture needle, used in this embodiment. A wire
of austenite-type stainless steel is cold-drawn to bring its crystals
into a fiber-like shape, thereby hardening the wire. Then, the drawn
wire is cut into a predetermined length to provide the needle material
100 of an original shape having a circular cross-section. Then,
one end of this needle material 100 is pointed.
Then, a mounting hole 100a is formed in the other or proximal end
portion of the needle material 100 and extends along the axis of
the needle material 100. More specifically, one pulse (whose pulse
duration is, for example, 1 msec.) of a laser beam composed of parallel
rays is outputted from a laser beam oscillator (not shown), and
is condensed by a condenser lens, and is supplied to the center
of the proximal end face of the needle material 100. The above pulse
of the laser beam has a very high instantaneous peak value, and
is concentrated on the center of the proximal end face of the needle
material 100 and therefore that portion of the needle material
100 to which the laser beam is applied is sublimed, thereby creating
the mounting hole 100a. The optical axis of the laser beam is in
alignment with the axis of the needle material 100. The focus of
the laser beam either coincides with the proximal end face of the
needle material 100 or is slightly spaced from this proximal end
face. The amount of this spacing is about 0.5 mm at the maximum
in the case where the depth of the mounting hole 100a is 1.25 mm.
Then, the proximal end portion of the needle material 100 that
is, its peripheral wall surrounding the mounting hole 100a, is annealed
by means of an apparatus shown in FIG. 1 thereby lowering the hardness
of the proximal end portion. Incidentally, the needle material 100
has fiber-like crystals because of the above cold drawing, and in
order to soften the needle material 100 by changing its crystals
into a grain-like shape, it is necessary to heat the needle material
100 up to 850.degree. C. to 1200.degree. C.
Referring to FIG. 1 a rotary disk 1 has an axis of rotation disposed
horizontally, that is, disposed parallel to the sheet of FIG. 1.
V-shaped grooves 1a are formed in the outer peripheral surface of
the rotary disk 1 and are circumferentially spaced from one another
at equal intervals. The needle materials 100 are received in the
V-shaped grooves 1a, respectively. The proximal end portion of the
needle material 100 is projected axially from the side face of the
rotary disk 1 by a predetermined distance longer than the mounting
hole 100a. In a stationary condition of the rotary disc 1 the needle
material 100 is held in position by a vertically-movable holder
member 2.
The apparatus of FIG. 1 comprises an oscillator (e.g. YAG laser
oscillator) 3 for outputting a laser beam. A laser beam (CW laser
beam) of a continuous wave emitted from the oscillator 3 is composed
of parallel rays, and is reflected by a mirror 4 and is condensed
by a condenser lens 5 and is fed into one end of a fiber 6. The
fiber 6 is called "a graded index-type fiber", and comprises
a core and a clad layer enclosing the core. The above condensed
laser beam is incident on one end face of the core of the fiber
6. The laser beam passes through the core of the fiber 6 and goes
out of the other end of the core in a spreading manner, and is again
condensed by condenser lenses 7 to be directed toward a focus F.
The focus F of the condenser lenses 7 is spaced a predetermined
distance D from the proximal end face of the needle material 100
held by the rotary disk 1 and the holder member 2. Therefore, the
laser beam converged on the focus F is directed toward the proximal
end face of the needle material 100 in a spreading manner, and is
converted into thermal energy there By continuing the supply of
this laser beam, for example, for about 1 second, the proximal end
portion of the needle material 100 is annealed.
In this embodiment, there is used the laser beam of the continuous
wave type which is lower in peak value than a pulsed laser beam.
And besides, as is well known, the fiber 6 of the graded index type
has the function of lowering the peak value of the laser beam to
smooth the laser beam. Therefore, an instantaneously-high thermal
energy will not be applied to the proximal end portion of the needle
material 100 and a uniform thermal energy is supplied to the needle
material 100. This achieves a good annealing.
The distance D between the proximal end face of the needle material
100 and the focus F of the laser beam is much longer than the distance
between the proximal end face and the focus of the first-mentioned
laser beam used to create the mounting hole 100a, and the area of
irradiation of the former laser beam at the proximal end face of
the needle material 100 is greater. Therefore, the distribution
of the thermal energy applied by the laser beam to the proximal
end face of the needle material 100 is relatively gentle, and an
excessive concentration of the thermal energy on the center of the
proximal end face does not occur. Namely, because of the characteristics
of the laser beam, although the energy is high at the central portion,
and decreases progressively toward the peripheral portion, the distribution
of this energy becomes gentler with increase of the area of irradiation
of the laser beam. As a result, a good annealing can be effected.
In this embodiment, since the optical axis X of the laser beam
lying between the other end of the fiber 6 and the proximal end
face of the needle material 100 is in alignment with the axis of
the needle material 100 a spot of the laser beam on the proximal
end face of the needle material 100 is concentric with the proximal
end face of the needle material 100. Therefore, the supplied thermal
energy can be distributed uniformly over the proximal end portion
of the needle material 100 in the direction of the periphery of
the proximal end portion.
As shown in FIG. 1 by causing the area of irradiation of the laser
beam at the proximal end face of the needle material 100 to substantially
coincide with the area of the proximal end face of the needle material
100 the radial distribution of supply of the thermal energy at
the proximal end face of the needle material 100 can be made gentle
as much as possible, and also the laser beam can be used efficiently.
FIG. 2 shows the distribution of the supplied thermal energy in
the direction of the length of the needle material when the annealing
is effected. Here, the overall length of the needle material 100
is 20 to 25 mm, and the depth of the mounting hole 100a is about
1.25 mm. Since the laser beam is supplied to the proximal end face
of the needle material 100 it will be readily appreciated that
the supplied thermal energy is the highest at the proximal end of
the needle material 100 and decreases progressively away from the
proximal end of the needle material 100. The thermal energy received
by that portion of the needle material 100 corresponding to the
bottom end (i.e., closed end) of the mounting hole 100a is substantially
equal to a minimum thermal energy Eo required for achieving the
annealing temperature. The above supplied thermal energy causes
a hardness distribution shown in FIG. 3. As is clear from this hardness
distribution, the hardness of the needle material 100 is the lowest
at its proximal end, and becomes higher progressively from the proximal
end toward the distal end of the needle material 100. That portion
of the needle material 100 corresponding to the bottom end of the
mounting hole 100a is substantially equal in hardness to that portion
of the needle material 100 not annealed (i.e., the portion except
for the proximal end portion).
Various conditions required for obtaining the above hardness distribution
will now h=described specifically with respect to a needle material
(first example) having an inner diameter of 0.05 mm and an outer
diameter of 0.55 mm and a needle material (second example) having
an inner diameter of 0.05 mm and an outer diameter of 0.30 mm. Input
voltages of the oscillator 3 are 240 V and 230 V, respectively,
with respect to the first and second examples, and output energies
are 10 W and 8 W, respectively, with respect to the first and second
examples. In each of the two examples, the distance D between the
focus F and the proximal end of the needle material 100 is 1.0 mm.
The time periods of irradiation of the laser beam are 1.0 second
and 0.9 second, respectively, with respect to the first and second
examples.
Variation or change of the proximal end portion of the needle material
100 will now be described with reference to FIGS. 4 to 6 which show
the sequence of the operation. FIG. 4 shows a condition in which
the mounting hole 100a has been formed in the proximal end portion
of the needle material 100 but the annealing is not yet applied
to the proximal end portion. As shown in FIG. 4 sharp burrs and
projections 100b are present on the inner and outer peripheral edges
of the proximal end of the needle material 100. Such burrs and projections
100b are fused and removed by the thermal energy supplied when effecting
the annealing, so that the inner and outer peripheral surfaces of
the proximal end are smoothly curved, as shown in FIG. 5. After
the annealing, one end portion of a gut 200 is inserted into the
mounting hole 100a, and in this condition the proximal end portion
of the needle material 100 is radially inwardly deformed or pressed
by a pair of dies, as shown in FIG. 6. A semi-cylindrical groove
and a tapered groove continuous therefrom are formed in each of
the opposed surfaces of the pair of dies. Therefore, after this
deformation, the proximal end portion of the needle material 100
has a cylindrical portion 110 of a reduced diameter having a length
L1 extending from the proximal end, and a tapered portion 120 of
a length L2 extending from the cylindrical portion 110. The overall
length L (=L1+L2) of this deformed portion is substantially equal
to the depth of the mounting hole 100a.
Effects of the annealing will now be discussed. After the formation
of the mounting hole 100a, the laser beam is applied to the proximal
end face of the needle material 100 to effect the annealing, and
therefore the burrs and projections 100b, produced on the proximal
end of the needle material 100 when forming the mounting hole 100a,
are fused and removed. This advantageously eliminates the possibility
that the gut 200 to be secured to the proximal end portion is cut
by the burrs and projections 100b on the proximal end of the needle
material 100. Also, since there exits no burr or projection projecting
radially from the outer peripheral surface of the needle material
100 the ability of the suture needle to penetrate will not be affected.
Further, there is not required any special working or processing
for removing the above burrs and projections.
As described above, the hardness distribution shown in FIG. 3 can
be obtained by applying the laser beam to the proximal end face
of the needle material 100 to effect the annealing. That portion
(extending over the length L1 in FIG. 6) of the proximal end portion
required to be deformed in a larger amount has a sufficiently low
hardness, and therefore the deformation can be effected satisfactorily
to provide the cylindrical portion 110. And besides, there is eliminated
the possibility that any portion of a high hardness remains at the
proximal end, thereby ensuring a good deformation of the proximal
end portion.
Although that portion extending over the length L2 (FIG. 6) increases
in hardness progressively away from the proximal end, this portion
can be satisfactorily deformed into the tapered portion 120 because
the amount of deformation of this portion decreases progressively
away from the proximal end. In other words, that region of the proximal
end portion shorter than the depth of the mounting hole 100a is
low in hardness, with the hardness of the tapered portion 120 increasing
progressively away from the proximal end, and therefore the proximal
end portion of the needle material 100 can have an increased mechanical
strength.
When effecting the annealing, since the laser beam is applied only
to the proximal end face of the needle material 100 pits and projections
and an oxide film which would adversely affect the penetrating ability
of the needle will not be formed on the outer peripheral surface
of the proximal end portion of the needle material 100. Therefore,
electropolishing can be omitted, or the time for such electropolishing
can be shortened.
In the embodiment of FIG. 1 in the case where the oscillator 3
emits the laser beam of a continuous wave as described above, the
use of the fiber 6 may be omitted, and the proximal end of the need
material may substantially coincide with the focus of the condenser
lenses 7. In the case where the oscillator 3 emits a pulsed laser
beam, at least one of the two requirements, that is, the passage
of the laser beam through the fiber 6 and the spacing of the proximal
end of the needle material 100 from the focus of the condenser lenses
7 must be met.
FIG. 7 shows another embodiment of the invention. Those portions
of this embodiment corresponding respectively to those in FIG. 1
are denoted respectively by identical reference numerals, and explanation
of such corresponding portions is omitted. In this embodiment, a
semi-transparent mirror 4' is disposed between an oscillator 3 and
a mirror 4 and a half of the energy of a laser beam is reflected
by the semi-transparent mirror 4', and is supplied to one end of
another fiber 6' of the graded index type via another condenser
lens 5'. This separated laser beam passes through the fiber 6' and
is condensed by condenser lenses 7'. A pair of laser beams, emitted
respectively from the pair of fibers 6 and 6' and condensed respectively
by the condenser lenses 7 and 7', have respective optical axes X1
and X2 inclined relative to the axis of the needle material 100.
The inclination angles of the axes X1 and X2 are equal to each other,
and are in the range of between 20.degree. to 60.degree.. The axes
X1 and X2 are spaced 180.degree. from each other circumferentially
of the needle material 100.
In the embodiment of FIG. 7 each of the laser beams is applied
to part of the proximal end face of the needle material 100 and
part of the outer peripheral surface of the proximal end portion
of the needle material 100. Therefore, the distribution of the supplied
thermal energy can be gentler in the direction of the length of
the needle material 100 than that of FIG. 1 and hence the hardness
distribution can be gentler, and the region of a low hardness can
be made longer. This embodiment is useful particularly when forming
a deep mounting hole 100a in the needle material 100. In this embodiment,
since the laser beams are also applied to the outer peripheral surface
of the proximal end portion of the needle material 100 small pits
and projections and an oxide film are formed thereon; however, this
outer peripheral surface can be made smooth by a short-time electropolishing.
In FIG. 7 for the sake of simplicity of the description, although
the pair of laser beams are applied to the needle material, more
than two laser beams can, of course, be applied to the needle material.
For example, in the case where three laser beams are used, the optical
axes of the three laser beams are spaced 120.degree. form one another
circumferentially of the needle material.
FIG. 8 shows a further embodiment of the invention. This embodiment
is basically similar in construction to the embodiment of FIG. 1.
A condenser lens corresponding to the condenser lens 5 of FIG. 1
is accommodated within a housing of an oscillator 3. Condenser lenses
corresponding to the condenser lenses 7 of FIG. 1 are accommodated
within a casing 10. The casing 10 is connected to the oscillator
3 via a fiber 6. In this embodiment, there is provided a bomb 11
filled with inert gas such as nitrogen gas and argon gas. A pair
of nozzles 13 are connected to the bomb 11 via tubes 12. The nozzles
13 inject the inert gas to the proximal end face of the needle material
10 and those portions adjacent thereto, so that the annealing is
effected in an atmosphere of the inert gas. By doing so, the formation
of an oxide film on the proximal end face of the needle material
100 is prevented. The annealing in the atmosphere of the inert gas
can, of course, be applied to the embodiment of FIG. 7.
FIGS. 9 and 10 shows a still further embodiment of the invention.
In this embodiment, the formation of the mounting hole and the annealing
are carried out by the same apparatus. More specifically, a rotary
disk 1 supporting the needle materials 100 is supported on a frame
30 through a rotatable shaft 1b, and the frame 30 is mounted on
a movable table 31. The movable table 31 is supported on a base
32 by a suitable means, such as a ball thread mechanism (not shown),
so as to be movable relative to the base 32 along the axis of the
needle material 100. A mechanism for vertically moving a holder
member 2 is also mounted on the movable table 31.
An optical axis Xo of a laser beam of parallel rays emitted from
an oscillator 3 is in alignment with the axis of the needle material
100. Disposed between the oscillator 3 and the needle material 100
are a light path converter 33 and condenser lenses 34 for condensing
the laser beam of parallel rays. The light path converter 33 includes
a pair of mirrors 3a and 33b, and each of the mirrors 33a and 33b
is pivotal about one end thereof.
The apparatus shown in FIGS. 9 and 10 includes a fiber 35 of the
graded index type disposed in spaced apart relation to the optical
axis Xo. One end of the fiber 35 is disposed in registry with one
mirror 33a whereas the other end of the fiber 35 is disposed in
registry with the other mirror 33b. A condenser lens 36 is disposed
between the one end of the fiber 35 and the mirror 33a, and a collimator
lens 37 is disposed between the other end of the fiber 35 and the
mirror 33b.
In the above construction, first, for forming the mounting hole
100a, the movable table 31 is located in a first position shown
in FIG. 9. More specifically, the proximal end of the needle material
100 is disposed either at the focal position of the condenser lenses
34 or slightly spaced therefrom. The mirrors 33a and 33b of the
light path converter 3 are disposed parallel to the optical axis
Xo of the laser beam. In this condition, when the oscillator 3 emits
one pulse of laser beam, this laser beam passes past those regions
adjacent to the mirrors 33a and 33b, and directly reaches the condenser
lenses 34 by which the laser beam is condensed and is supplied to
the center of the proximal end face of the needle material 100
thereby forming the mounting hole 100a.
Then, the annealing is effected. More specifically, as shown in
FIG. 10 the movable table 31 is moved away from the oscillator
3 into a second position. In this second position, the proximal
end face of the needle material 100 is spaced a distance D from
the focus F of the condenser lenses 34. Also, in the light path
converter 33 the mirrors 33a and 33b are pivotally moved through
45.degree. in clockwise and counterclockwise directions, respectively.
In this condition, the oscillator 3 outputs 1000 pulses of laser
beam per second. This pulsed laser beam is reflected by the mirror
33a, and passes through the condenser lens 36 the fiber 35 and
the collimator lens 37 and is reflected by the mirror 33b, and
is further converged by the condenser lenses 34 toward the focus
F, and then is fed from the focus F to the proximal end face of
the needle material 100 in a spreading manner, thereby effecting
the annealing. The smoothing effect achieved by the fiber 35 and
the effect achieved by the spacing of the proximal end face of the
needle material 100 from the focus F have already been described
above, and therefore explanation of such effects is omitted here.
In this embodiment, for effecting the annealing, instead of a laser
beam of a continuous wave, a number of pulses of laser beam are
outputted. When effecting the annealing, it is necessary to satisfy
at least one of two requirements, that is, the conversion of the
laser beam path and the movement of the needle material 100 along
its axis. In the case where it is necessary to effect only the light
path conversion, the manufacturing time can be reduced greatly.
In this embodiment, the formation of the mounting hole and the
annealing are carried out using the oscillator for emitting the
pulsed laser beam. At present, as far as the inventor of the present
invention knows, there does not exist any oscillator which can be
switched between one mode for emitting a laser beam of a continuous
wave and another mode for emitting one or more pulses of laser beam;
however, if such an oscillator is used, the formation of the mounting
hole can be done by the pulsed laser beam, and the annealing can
be done by the laser beam of a continuous wave, without the need
for the conversion of the laser beam path and the movement of the
needle material.
The present invention is not restricted to the above embodiments,
and various modifications can be made. For example, as the energy
beam for the annealing, a light beam from a halogen lamp, an electron
beam, an ion beam, or a plasma jet can be used. Also, for the formation
of the mounting hole, any of the above energy beams except for the
above light beam, a water jet, or a drill can be used. In the case
where the drill is used to form the mounting hole, the annealing
is carried out prior to the formation of the mounting hole.
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