Syringe needle abstract
A sheath for protecting and maintaining sterile a syringe needle
and for preventing breakage of the needle during use is disclosed.
The sheath is mounted on a syringe of the type used for introducing
liquid medication into flexible bags for the administration of intravenous
solutions, and serves to guide and protect the needle as it is inserted
into the flexible inlet tube of such bags and to hold the needle
and syringe in alignment during the injection of medication to prevent
breakage of the needle. The syringe housing is formed with a boss,
or hub, through which the needle extends, and the sheath is secured
to this boss by means of an inwardly turned axial mounting collar.
An end wall partially closes the protective sheath and abuts the
closed end of the syringe housing to provide a relatively large
contact area between these two elements to hold them in alignment.
The annular collar frictionally engages the syringe body hub to
securely hold the protective sheath in place. The protective sheath
preferably is slightly conical, tapering outwardly from its closed
end to an open end which is slightly larger in diameter. The open
end of the sheath terminates in an outwardly turned annular flange
having a flat surface adapted to engage the outer wall of a container
to hold the needle and syringe in the proper angular relationship
therewith. A suitable cap or cover is provided for the sheath to
enclose the syringe needle until it is to be used.
Syringe needle claims
I claim:
1. A syringe assembly including a syringe housing having a front
wall substantially closing one end of the housing and hub means
one said front wall for receiving and holding a syringe needle,
said hub extending forwardly of said front wall and said needle
having a cannula portion extending out of said hub and forwardly
of said syringe housing, and a protective sheath mounted on said
housing coaxially with and spaced radially outwardly from said needle
for protecting said cannula portion and extending along at least
a portion of the cannula portion, said sheath including:
a substantially cylindrical side wall having a longitudinal axis;
a rear wall located at and substantially closing a first rearward
end of said sheath, said rear wall extending generally radially
inwardly from said side wall and defining an angle with respect
to said axis that corresponds to the angle of said front wall with
respect to said syringe needle, whereby when said sheath is mounted
on said housing said rear wall of said sheath abuts said front wall
of said syringe housing throughout its corresponding radial extent;
annular flange means extending forwardly from said rear wall into
said sheath, said flange means being coaxial with said side wall
and defining a central aperture, said flange forming a support and
alignment collar adapted to receive said hub and cannula portion
and to engage said forwardly extending hub to mount said sheath
on said housing so that said rear wall abuts said front wall of
said housing, said collar being substantially coextensive with said
hub within said sheath to provide an axial mounting that resists
lateral motion of said sheath with respect to said cannula portion,
said sheath being welded to said syringe housing to provide a rigid
protective structure; and
removable cap means adapted to close the second, forward end of
said sheath and enclose said cannula portion.
2. The syringe assembly of claim 1 wherein the side wall of said
sheath is tapered to define a truncated cone having a relatively
small included angle.
3. The syringe assembly of claim 1 wherein said sheath further
includes an outwardly turned annular flange at said second end,
said flange having a forward face lying in a plane perpendicular
to the axis of said sheath, said flange being adapted to receive
said cap means.
4. The syringe assembly of claim 1 wherein said hub means is coaxial
with said syringe housing, and said collar is coaxial with said
sheath, whereby said sheath is coaxially mounted on said syringe
housing.
5. The syringe assembly of claim 1 wherein said sheath further
includes an outwardly turned annular flange, and wherein said cap
means includes an annular side wall having an internal circumferential
groove corresponding to and adapted to receive said outwardly turned
annular flange, whereby said cap means is mounted on said sheath.
Syringe needle description
BACKGROUND OF THE INVENTION
The present invention relates, in general, to syringes for introducing
liquid medication into containers such as intravenous solution bags,
and more particularly to an improved protective sheath, or hood,
for the needle extending from the syringe body.
Syringes particularly designed for use in injecting liquid medication
into containers such as flexible bags, glass bottles, or other sterile
containers, wherein the medication is to be mixed with another liquid
in the container, are well known. Syringes used with flexible bags,
for example, are illustrated in U.S. Pat. Nos. 3828779 and 3945382
both issued to R. W. Ogle. As described in these and similar patents,
such syringes comprise an elongated, generally cylindrical hollow
body portion having an open end and a closed end. A boss is formed
at the closed end, the boss carrying a needle which extends through
the length of the tubular body portion, passing through the boss
and forming an exterior cannula portion which is adapted to inject
fluid into the container. A sheath is generally provided to surround
the cannula portion and is mounted at one end on the boss, with
the opposite end being adapted to engage the additive-receiving
orifice of, for example, an intravenous (IV) solution bag. The open
end of the sheath passes over the orifice and guides the cannula
into and through a normally closed plug within the orifice, with
the sheath generally being designed to limit the distance the cannula
can travel into the orifice to prevent it from piercing the container.
Located within and concentric with the syringe housing is an inner
cylindrical wall portion which is adapted to receive a vial or other
container for the medication which is to be added to the IV bag.
The vial includes a resilient stopper which generally has a thin
central portion adapted to be pierced by the upper end of the needle
carried by the syringe housing. The stopper may be provided with
external threads which engage corresponding threads on the interior
of the cylindrical wall portion, with the wall of the vial surrounding
the wall portion and extending into the annular space between the
wall portion and the syringe housing. When the vial is placed over
the end of the wall portion and into the syringe, the syringe needle
pierces the stopper so that the medication can flow from the vial
through the needle and into the IV bag. By pressing the vial down
into the syringe housing, the stopper is forced up into the vial
and fluid therein is forced out through the needle.
In order to eject the fluid from the vial into the IV bag, it is
often necessary to exert considerable force on the vial and syringe
housing. Further, because the orifice into which the medication
is injected is flexible, the relationship between the syringe and
the IV bag is not constant, and it has been found that as a result
the needle guide cover often breaks away from the syringe housing
boss, causing breakage of the needle or, in some cases, a piercing
of the IV solution bag, thereby contaminating the intravenous solution.
Further, because of the relatively unsecure connection between the
needle sheath and the syringe housing, the sheath can easily be
broken away in handling of the syringe even before it is put into
use, thus rendering the syringe useless for its intended purpose.
In the needle cover and guide structure typified by the above-mentioned
patents, the outer end of the cover is constructed to provide an
exact fit with a specifically shaped container orifice, thereby
limiting the usefulness of the syringe to that particular container.
Thus, the syringe cannot be used as a general purpose device in
combination with a variety of containers without removal of the
cover for the needle or cannula, and consequent exposure of the
needle to contamination.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide
an improved needle or cannula sheath for use with syringes which
overcomes the problems of breakage and consequent contamination,
and which further is adapted for use with a wide variety of container
orifices.
It is a further object of the invention to provide a needle or
cannula sheath which is designed to provide firm and stable guidance
between a container orifice and the cannula portion of a syringe
to insure that the needle enters the container correctly and without
danger of piercing the sides thereof, and further is limited as
to the distance which it can travel into the container orifice for
the same purpose.
In accordance with the present invention, there is provided a syringe,
needle sheath and cap assembly which overcomes the disadvantages
of the prior art devices and which provides a secure and accurate
guide for the cannula portion of the syringe needle, protecting
it against breakage while in use, or beforehand in the manufacturing,
shipping and handling of the syringe. Thus, in accordance with the
present invention there is provided a protective hood or sheath
which is firmly secured to the syringe housing at one end and which
extends outwardly to an open distal end portion which is adapted
to recieve IV bag and other container inlet openings of various
sizes and shapes. A slight taper in the cover or sheath of the present
invention not only facilitates manufacture of the device, but serves
to guide the container inlet into the sheath and to insure that
the cannula enters the approximate center of the inlet device for
injection of the liquid medication. The sheath is of sufficient
length that the distal end thereof engages the exterior surface
of the container into which the medication is to be injected, preventing
the inlet device from entering too far into the sheath and thereby
limiting the distance which the needle can travel to prevent the
needle from piercing the side walls of the container.
Preferably, the sheath does not extend the full length of the cannula,
leaving the end thereof extending beyond the distal end of the sheath
to accommodate injection of the medication into containers which
do not include the elongated inlet openings mentioned above. For
example, some glass bottles in use today have a top inlet, or mouth,
which is closed by a thin diaphragm, but which has a diameter greater
than that of the interior diameter of the sheath. In such cases,
the portion of the cannula extending beyond the sheath is of sufficient
length to pierce the diaphragm, whereby the medication can be injected
into the container without requiring removal of the sheath.
The connection between the sheath and the syringe housing comprises
a radially inwardly extending wall at the end of the sheath which
abuts the end of the syringe to which it is to be connected. This
radially extending wall is at an angle with the side wall of the
sheath which corresponds to the angle of the syringe face which
it abuts so that there is an intimate contact therebetween along
substantially the entire radial extent of the sheath end wall. The
inwardly extending end wall terminates in an annular flange which
is coaxial with the sheath and which extends into the sheath to
form an annular collar which is adapted to engage a corresponding
outwardly extending boss, or hubs, formed on the end of the syringe
and adapted to carry the syringe needle. The sheath is secured on
the syringe body by positioning the collar around the hub so that
it engages the hub, and the end wall of the sheath is welded or
otherwise secured to the front wall of the syringe body. This arrangement
holds the sheath firmly in place, the abutment between the adjacent
front face and end wall providing a strong support against lateral
deflection of the sheath and consequent loss or breakage of it or
of the needle, which can lead to contamination of the medication.
The distal, or outward, end of the sheath is covered by a suitable
cap which cooperates with the sheath to maintain the cannula portion
of the needle in a sterile condition until the syringe is ready
for use.
Thus, the sheath of the present invention provides a sterile cover
for a syringe needle, the sheath being securely connected to the
syringe body for greatly improved protection against breakage and
consequent contamination of the device, and further provides a configuration
which facilitates use of the syringe and permits it to be combined
with the entrance openings to a variety of containers.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and additional objects, features and advantages of
the present invention will become apparent to those of skill in
the art upon a consideration of the following detailed description
thereof, taken in conjunction with the accompanying drawings, in
which:
FIG. 1 is a partially exploded, partially sectional view in perspective
of a syringe assembly embodying the improved syringe needle cover
of the present invention;
FIG. 2 is an exploded view in partial section of the syringe needle
cover of the present invention in combination with a syringe body
of smaller capacity; and
FIG. 3 is a sectional view of the syringe and needle cover assembly
of FIG. 2.
DESCRIPTION OF A PREFERRED EMBODIMENT
Turning now to a more detailed consideration of the invention,
there is illustrated in the figures a syringe assembly generally
indicated at 10 in FIG. 1 and at 12 in FIGS. 2 and 3. This assembly
includes in FIG. 1 a syringe housing 14 to which is secured a syringe
needle sheath 16. The syringe housing is illustrated in this figure
as being larger in diameter than the sheath 16 the syringe housing
representing in this case a device having a capacity of, for example,
50 cc. In FIGS. 2 and 3 the assembly consists of a syringe body
18 to which the needle cover 16 may be secured, but the syringe
body is of smaller diameter and may have a capacity of, for example,
10 cc. Thus, it will be recognized that the syringe needle cover
of the present invention may be mounted on a variety of syringe
housings, the particular syringe depending upon the quantity of
medication to be injected or the use to which the device is to be
put.
As may be seen more clearly in FIG. 3 the syringe body 18 includes
an outer cylindrical wall 20 and a forward end wall 22 which closes
one end of the housing and provides on its outer surface a front
face 24. Centrally located in wall 22 is an annular boss, or hub,
26 which is concentric with the housing 18. The hub carries suitable
means such as the illustrated mounting post 28 for securing a syringe
needle 30 within and coaxial to housing 18. In the illustrated configuration,
the mounting post 28 is secured to or is formed as an integral part
of the forward end of hub 26 and extends outwardly therefrom, but
other configurations may be used. In the illustrated form, the mounting
post 28 comprises a hollow cylinder carrying a plurality of mounting
discs 32 through which the needle passes and which secure the needle
against longitudinal motion in the syringe housing.
As is known in the art, needle 30 extends substantially the full
length of housing 18 terminating at its rearward end in a chisel
point 32 which is adapted to pierce the stopper in a vial (not shown)
of medication or other fluid which is to be injected through the
needle. The opposite end of the needle extends out of the mounting
post portion of the hub to form the cannula portion 34 of the needle.
The distal end of the cannula portion terminates in a chisel point
36 which is adapted to pierce the stopper or other cover for the
inlet opening portion of the container into which the medication
or other liquid in the vial is to be injected.
The vial of liquid to be injected is secured by means of a threaded
stopper (not shown) adapted to engage the upper end of an interior,
upstanding, cylindrical wall portion 38 which is concentric to the
housing 18 and which is adapted to fit into the vial. The wall portion
38 preferably incorporates suitable threads 40 which receive the
corresponding threads on the vial stopper, with the annular space
42 defined between the wall portion 38 and the housing 18 serving
to receive the wall of the vial as the medication is ejected through
needle 30.
Although not illustrated in FIG. 1 it will be understood that
the interior of syringe housing 14 is similar to the syringe housing
shown in FIGS. 2 and 3 and thus incorporates a front wall portion
44 which carries a centrally located hub 46 similar to hub 26 of
FIGS. 2 and 3 the hub carrying a mounting post 48 which supports
a longitudinally extending needle 50.
The needle cover or sheath 16 as illustrated in all three figures,
includes a side wall portion 52 which preferably tapers outwardly
from its near or small diameter end 54 to its distal or larger diameter
end 56 the taper being constant throughout the length of the sheath.
The sheath thus forms a truncated cone having a relatively small
interior angle so that the wall 52 tapers outward at a relatively
small angle. The distal end 56 terminates in an outwardly turned
flange 58 the flange having a flat forward surface 60 which preferably
lies in a plane perpendicular to the axis of the sheath.
The near, or small diameter, end of the sheath is partially enclosed
by an inwardly extending end wall portion 62 which may be formed
as a continuation of the side wall portion 52 and which extends
substantially radially inwardly to define a rear surface 64. The
end, or rear, wall 62 is shown in FIG. 3 as being substantially
perpendicular to the axis of sheath 16 but it should be understood
that this angle may be varied if desired, the only restriction being
that the angle of the rear wall 62 correspond to the angle of the
outer surface of the front wall of the syringe housing, i.e., surface
24 of the front wall 22 of syringe 18 so that the walls 22 and
62 will abut each other when the syringe 18 and the sheath 16 are
axially aligned and assembled. When the sheath is properly mounted
on the syringe housing, the face 24 of the end wall 22 of the syringe
body will be in direct abutting contact with the face 64 of the
wall 62 of the sheath throughout the corresponding radial extent
of the two walls. Thus, if the syringe is of greater diameter than
the sheath, the face-to-face contact will be limited to the radial
extent of the sheath, while if the syringe is of smaller diameter,
the contact will be limited to the radial extent of the syringe
housing.
The inwardly turned end wall 62 terminates in an axial flange 66
which defines a circular opening in wall 62 and which defines a
support and alignment collar having an inner diameter substantially
equal to the outer diameter of the boss 26. The support collar 66
thus serves to align the sheath with the syringe housing 18 when
it engages the exterior surface of the boss, so that the sheath
will be properly located when it is welded to the face of the syringe
body. The angular relationship between the collar 66 wall 62 and
wall 52 provides a rigid connecting structure which insures that
the sheath will remain in axial alignment with the syringe body
to protect the cannula portion 34 of the needle. As shown, flange
66 extends into the interior of the sheath so that it is substantially
coextensive with hub 26 to provide a rigid lever arm that protects
the sheath against lateral motion with respect to the axis of the
syringe and prevents the welded abutting walls from being broken
apart.
The distal end of the sheath is adapted to receive a cap 68 the
cap including a cylindrical side wall 70 closed at its forward end
by means of a forward wall 72 and carrying at its rear, or open,
end a shoulder portion 74 which defines an inwardly facing circumferential
groove. This groove is adapted to receive the outwardly turned flange
58 formed on the distal end of sheath 16 in a snap fit arrangement
whereby the cap 68 may be securely mounted on the sheath to provide
a sealed enclosure for the syringe needle. The close fit between
the cap 68 and the sheath 16 as well as the close fit between the
collar 66 and boss 26 permit maintenance of a sterile atmosphere
within the sheath, if desired.
As illustrated in FIGS. 1 and 2 the sheath 16 is adapted to receive
a variety of container inlet openings by means of which medication
may be injected into the containers. Thus, for example, in FIG.
1 there is illustrated at 76 a conventional flexible orifice of
the type used on conventional IV solution bags 78. Orifice 76 is
an inlet orifice which contains a suitable plug that is pierced
by the cannula portion of needle 50. The end face 60 of the sheath
limits the distance which the needle 50 can move into the inlet
orifice 76 and when the front edge of the sheath is in engagement
with the IV bag 78 it provides stability to the syringe while the
medication is being injected. A conventional outlet orifice for
the IV bag 78 is indicated at 80.
A different IV bag structure is illustrated in FIG. 2 at 82 this
container utilizing a rigid orifice construction as indicated at
84. Inlet orifice 84 is of a larger diameter than the construction
illustrated in FIG. 1 and thus would normally require a change
in the syringe sheath assembly if medication were to be injected
into both containers from the same or a commonly designed syringe.
However, with the present invention the same sheath arrangement
can be used with both containers, for the sheath 16 will also fit
over orifice 84 and guide the needle 30 to pierce the orifice plug
86. Again, the forward wall portion 60 of the sheath engages the
container wall 82 to limit the extent of the needle into orifice
84 and to provide stability to the syringe assembly as the fluid
is injected. It will be apparent from the foregoing that the sheath
16 is adapted to receive a variety of inlet orifices and to serve
as a guide for the syringe needle to insure proper insertion of
the needle and stability to the syringe assembly during use.
From the foregoing it may be seen that the present invention provides
an improved sheath structure for covering, protecting and guiding
syringe needles, and which will prevent and overcome the problems
which existed with prior art needle covers. Although the present
invention has been disclosed in terms of a preferred embodiment
thereof, it will be apparent to those of skill in the art that variations
and modifications can be made without departing from the true spirit
and scope of the invention as defined in the following claims.
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