Note: Descriptions are shown in the official language in which they were submitted.
CA 02269005 1999-04-14
NEEDLB INJECTIOIT-FlICIIrITl~TIll~i DEVICE
The present invention relates to a manually operable needle
injection-facilitating device intended for use as an aid in
the injection of fluid medication by means of a hypodermic
syringe or medication pen. The invention is particularly
useful to patients who are frequently required to self
administer medication such as insulin in the case of
diabetes.
The major difficulty that exists in the self-handling of a
hypodermic syringe or medication pen by a person other than
a trained professional is the accurate insertion and
penetration of the needle into the skin of the patient. This
problem is particularly compounded for individuals who are
visually impaired, have an aversion to needles and
injections, or lack fine motor control in attempting to
administer their own medication.
Various injector assist devices for facilitating hypodermic
injections for in-home use, such as for insulin injections,
are known for operation with conventional hypodermic syringes
while simultaneously controlling the depth of penetration of
the hypodermic needle. However, for an individual with
impaired vision or manual dexterity, these injector assist
devices have a number of disadvantages that make them
inconvenient and less desirable to use. One disadvantage
associated with some present injector assist devices is that,
by virtue of the number of components from which the devices
are comprised, they are complicated with respect to assembly
of the device. For example, in the case of U.S. Patent No.
5,634,906 of Haber et al., several components of the
apparatus are adapted with various peripheral retaining
grooves and ridges so that they may interface precisely in
combination with each component of a dose metering syringe,
i.e. the medication housing, medication cartridge, needle
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hub and barrel. As such, considerable coordination is
required to ensure that each component of the device is
properly interfaced in combination with each component of the
syringe so that it may function properly. Another
disadvantage found among other injector assist devices is
that they have components sized to accommodate only a limited
number of commercial syringes and therefore, are not
compatible with a medication pen. Examples of these devices
are disclosed in U.S. Patent No. 4,601,708 of Jordan and
' Canadian Patent No. 536,718 of Transue. On the other hand,
some prior art injector devices are more simplistic in
design, comprising essentially one tubular component adapted
to fit over the barrel of a syringe. Such devices,
described, for instance, in U.S. Patent No. 5,417,662 of
Hjertman et al. and U.S. Patent No. 4,373,526 of Kling, have
a number of angled surfaces within the interior wall of a
tube, which are designed to inter-fit and inter-engage with
annular projections of a conventional syringe barrel.
However, the interlocking arrangement between the injector
assist device and the syringe makes the device more difficult
to manipulate in terms of its attachment to and/or removal
from a syringe, especially for a person with poor manual
dexterity.
Accordingly, an object of the invention is to provide an
injector assist device comprised of a minimal number of
component parts, which can be quickly and easily incorporated
with either a conventional hypodermic syringe or a medication
pen, is easy to handle and manipulate, and can reliably and
safely facilitate administration of a medicament dosage,
particularly by an individual who is visually impaired or
lacks fine motor control.
Another object of the invention is to provide an improved
needle injection-facilitating device which by function and
structural design can accommodate a conventional hypodermic
syringe or medication pen and which greatly simplifies and
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safely facilitates the self-injection procedure for in-home
use application.
According to the invention there is provided a needle
injection-facilitating device comprising:
(a) an outer hollow sl..eeve opening into a flared base;
(b) an inner hollow sleeve having an interior surface
configured to receive a syringe or medication pen, said
inner sleeve having a retaining collar at its distal end
with an aperture sized to receive a hub of a hypodermic
needle and through which the needle projects, wherein
said inner sleeve is capable of sliding movement inside
said outer sleeve, between a retracted position and an
operating position; and
(c) biasing means disposed between the inner sleeve and the
outer sleeve which upwardly biases the inner sleeve to
said retracted position in whi.c:h a hypodermic needle
received within said inner sleeve is shielded from view
by the base of said outer sleeve;
whereby placement o:f the flared base of said outer sleeve
in contact with an injection site followed by manual
application of a downward axial force to a syringe or
medication pen received :in said inner sleeve advances the
inner sleeve from the retracted position to the operating
position against the bia;~ of said biasing means to effect.
administration of an injection; and subsequent removal of said
downward force permits movement of said inner sleeve under the
influence of said biasing means back to the retracted po~~ition
and concomitant extraction of the hypodermic needle of said
syringe or medication pen from the injection site.
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Thus, the invention affords a needle injection-facilitating
device designed for use with a hypodermic syringe or medica-
tion pen. The device comprises an outer hollow longitudinal
cylindrical sleeve of larger diameter with an inverted
frusto-conical base that allows a 90° angle of insertion of a
hypodermic needle subcutaneously into a patient. In a second
embodiment of the device, the frusto-conical base is beveled
to allow a 45° angle of insertion. By beveling the base of
the outer sleeve in this way, a preferred angle of insertion
at the targeted injection site can be achieved for a particu-
lar medical application while reducing the possibility of a
bent syringe needle. The frusto-conical base also assists in
guiding and stabilizing the movement of the hypodermic
syringe, or medication pen, at a particular location by an
individual who is visually impaired or lacks fine motor
control. Furthermore, because the base of the outer sleeve
shields the hypodermic needle from view prior to and during
injection, the psychological barrier of needle insertion will
be alleviated for the user who may experience anxiety at the
sight of an exposed needle.
An inner hollow cylindrical sleeve of smaller diameter is
slidably disposed within the outer sleeve and can hold various
size adaptors to customize the device for use with a given
type or size of syringe. Located at the distal end of the
inner sleeve is a retaining collar with an aperture sized to
receive the hub of a hypodermic needle and through which the
needle projects. In a retracted position, the retaining
collar rests inside a retaining groove circumscribed within
the inner wall of the outer sleeve. A velcro patch may be
attached on the outside face of the distal end of the inner
sleeve and has a diameter and inner hole sized to match the
dimensions of the retaining collar and its aperture,
respectively.
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The two sleeves slide along a common longitudinal axis in a
telescopic arrangement and their movement relative to one
another is controlled by biasing means, such as of spring
means, which advantageously comprises springs disposed
inside a pair or plurality of grooves set within the inner
wall of the outer sleeve. The springs are compressed when an
axial force is applied to the syringe prior to and during
insertion of the hypodermic needle. In another embodiment of
the injection needle-facilitating device, a single helical
coil spring encircles the upper portion of the inner sleeve
and seats on the peripheral edge at the extreme proximal end
of the outer sleeve. An adjustable retaining ring located at
the proximal end of the inner sleeve secures the spring to
the device. Adjustment of the retaining ring will determine
the tension of the spring and to a lesser degree, the extent
of needle projection beyond the inner sleeve.
The depth of penetration of the hypodermic needle is
determined by the exterior face of the inner sleeve coming in
contact with the skin surface of the user. This
automatically accommodates non-flat, e.g. concave or convex
body surfaces, where the point of injection is non-planar
with the periphery of the frusto-conical base. After fluid
medication has been delivered at the targeted injection site,
the needle is extracted by the force of expansion of the
spring following release of the axial force to the syringe.
Another embodiment of the device simply comprises a fixed
outer component which is a hollow longitudinal cylindrical
sleeve with an inverted frusto-conical base that allows a
90° placement on the skin surface. The inner dimensions of
the fixed sleeve enable it to be coupled to a medication pen,
however, the sleeve can be easily adapted for use with
commercial type hypodermic syringes by insertion of various
size adaptors. Located at the distal end of the fixed sleeve
is an aperture sized to receive the hub of a hypodermic
needle and through which the needle projects. In the case of
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the operation of the fixed sleeve, it is initially positioned
at the preferred injection site of the user utilizing the
inverted frusto-conical base as a guide. In other words, for
this particular embodiment of the injection needle-
s facilitating device, the fixed sleeve is not assembled with
the barrel of a syringe prior to its placement on the surface
of the skin. Once the user has chosen a preferred injection
site by orientation of the fixed sleeve, the syringe is then
inserted through the sleeve during the injection procedure.
In this way, the frusto-conical base of the fixed sleeve
serves to guide, position and stabilize the movement of the
syringe by a visually or manually impaired individual while
ensuring the proper angle and depth of entry of the needle,
thereby reducing the possibility of a bent syringe needle.
In the following description, the invention will be explained
in detail with the aid of the accompanying drawings which
illustrate preferred embodiments of the present invention:
Figures la and 1b are cross-sectional views of a needle
injection-facilitating device in combination with a
hypodermic syringe in a retracted and an operating position,
respectively, following placement at a targeted injection
site:
Figures 2a and 2b are cross-sectional views of a needle
injection-facilitating device of Figure 1 in a normal
retracted position and a compressed position, respectively,
without attachment to a hypodermic syringe or medication pen;
Figures 3a to 3e show plan and cross-sectional views of
components which comprise the needle injection-facilitating
device of Figure 2:
Figures 4a and 4b show cross-sectional views of a second
embodiment of a needle injection-facilitating device in
combination with a hypodermic syringe in a retracted and an
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operating position, respectively, following placement at a
targeted injection site; and
Figure 5 is a side view, partly in cross-section, of a needle
injection-facilitating device according to a third embodiment
of this invention.
As illustrated in Figures 1 to 3, a first embodiment of a
needle injection-facilitating device 1 comprises an outer
component 2 which is a hollow, longitudinal cylindrical
sleeve portion 2a surmounting an inverted frusto-conical
base 4 the periphery 5 of which is normal to the surface of
the skin upon placement of the needle injection-facilitating
device 1 thereon. An inner component 3 is a hollow
cylindrical sleeve dimensioned to receive the distal end of
the barrel of a hypodermic syringe 6, or medication pens
and to be slidably disposed within the outer component 2.
The inner component 3 can also hold various size adaptors 8
to customize the device for use with a particular type or
size of syringe. Located at the distal end of the inner
sleeve 3 is a retaining collar 9 with an aperture 10 sized to
receive the hub il of a hypodermic syringe 6 and through
which a needle 12 of such syringe projects. In a retracted
position, the retaining collar 9 rests inside a retaining
groove 13 circumscribed within the inner wall 14 of the outer
sleeve 2. A velcro patch 15, fixed on the outside face of
the distal end of the inner sleeve 3, has a diameter and
inner hole sized to match the dimensions of the retaining
collar 9 and its aperture 10, respectively. The two
components 2 and 3 are coaxially aligned relative to one
another and the inner component 3 slides along a common
longitudinal axis in a telescopic arrangement. Their
movement is controlled by means of a pair of springs 16 which
CA 02269005 2001-10-03
are compressed when an axial force is applied to the
syringe 6 prior to and during insertion of the hypodermic
needle 12. A pair of longitudinal grooves 17, circumscribed
at diametrically opposed locations within the inner wall 14
of the outer sleeve 2, house the pair of springs 16. Each
spring 16 is secured by means of a pair of pins 18 and 19.
The upper portion of each spring 16 is helcin place by a
pin 18 which is inserted through pin-holes 20 located near the
proximal end of the inner sleeve 3 and within the pair of
grooves 17. The lower portion of each spring 16 is held in
place by a pin 19 inserted through pin-holes 21 located
within the wall of the outer sleeve 2 located at its distalend~
When a downward axial force is applied, the pair of pins 18
slide within the grooves 17 formed in the inner wall 14 of
the outer sleeve 2 thereby compressing the springs 16. After
the fluid medication has been delivered at the targeted
injection site, release of the axial force on the syringe 6
permits the expansive force of the springs 16 to drive the
inner sleeve 3 back to its original retracted position while,
simultaneously extracting the hypodermic needle 12 from the
injection site.
In the rest condition of Figure la, the inner sleeve 3 which
encloses the barrel of the syringe 6 is biased in a retracted
position relative to the outer sleeve 2 such that the
retaining collar 9 of the inner sleeve 3 sits inside the
retaining groove 13 of the outer sleeve 2. In this position,
the hypodermic needle 12 is shielded from view when the
needle injection-facilitating device 1 is placed on the skin
surface at the targeted injection site. The pair of
springs 16 housed in the grooves 17 of the inner wall 14 of
the outer sleeve 2 are in a relaxed conformation. Prior to
coupling the needle injection-facilitating device 1 with the
syringe 6, an alcohol swab may be attached to the velcro
patch 15 located at the distal face of the inner sleeve 3.
After the needle injection-facilitating device 1 is assembled
with the hypodermic syringe 6, or medication pen, it is
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placed on the skin surface at the desired injection site.
The large surface area circumscribed by the periphery 5 of
the inverted frusto-conical base 4 helps to stabilize the
orientation of the syringe 6 so that the direction of the
needle 12 is maintained in a position perpendicular to the
surface of the skin. When a downward axial force is applied
to the main barrel of the syringe 6, as illustrated in Figure
lb, the inner sleeve 3 is advanced distally resulting in
compression of the springs 16. As the hypodermic needle 12
begins to penetrate the skin, the movement of the inner
sleeve 3 continues until the exterior face of the retaining
collar 9 comes in contact with the surface of the skin,
thereby controlling the depth of penetration of the
needle 12. When injection of the fluid medication has been
administered in the conventional manner, subsequent release
of the axial force permits the springs 16 to expand to their
relaxed conformation. The force of expansion of the
springs 16 propels the inner sleeve 3 back to its original
retracted state, while simultaneously extracting the
hypodermic needle 12 into a shielded position within the
frusto-conical base 4 of the device' 1.
A second embodiment of the injection needle-facilitating
device 1 is illustrated in Figures 4a and 4b in which the
periphery 5a of an inverted frusto-conical base is beveled
to allow a 45° insertion of the hypodermic needle 12 relative
to placement of the device on the skin surface. In this
embodiment the end face 9a of the inner sleeve 3 is also
offset or beveled to permit flat contact thereof with a skin
surface. Figures 4a and 4b provide an illustration of the
device 1 in both a resting and injection position,
respectively. The method of operation of the device 1 in
this particular embodiment is essentially the same as that
described above for Figures 1a and lb.
The injection needle-facilitating device 1 of the embodiment
shown in Figure 5 incorporates a single helical coil
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spring 22 which encircles the upper portion of the inner
sleeve 3 while resting on the peripheral edge at the extreme
proximal end of the outer sleeve 2. An adjustable retaining
ring 23, located towards the proximal end of the inner
sleeve 3, secures the helical spring 22 to the device 1. The
retaining ring 23 has a set of screw threads to match those
extending around the exterior of the inner sleeve 3 at the
proximal end thereof. Adjustment of the retaining ring 23
will vary the tension of the spring 22 and, to a lesser
degree, the extent of needle 12 projection beyond the distal
end of the inner sleeve 3. As Figure 5 illustrates, the
helical spring 22 is in a relaxed conformation when the
device 1 is in a resting condition. As such, the inner
sleeve 3 is biased in retracted a position relative to the
outer sleeve 2. In this position, the hypodermic needle 12
is shielded from view.
The injection needle-facilitating device may be fabricated
from either metal or heat-resistant plastic.
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