Syringe needle abstract
A method and apparatus for sterilizing and destroying a syringe
needle includes a rotating needle carriage that receives a needle
in a loading position. The needle carriage is rotated downwardly
to a cut-off position. At the cut-off position, two opposing contact
blades pinch the needle, which electrically connects the positive
and negative terminals of a battery. Current flows through the contact
blades and the needle, thereby melting the needle. A slight further
rotation of the needle carriage causes the contact blades to shear
the needle. The sheared portion of the needle then falls into a
waste compartment in the bottom of the apparatus. When the syringe
is removed from the needle carriage, the needle carriage rotates
upwardly and returns to the loading position.
Syringe needle claims
What is claimed is:
1. An apparatus for removing the needle portion of a syringe comprising:
a housing;
a needle carriage for receiving a needle in a loading position,
said needle carriage being rotatably connected to the housing from
the loading position to a cut-off position;
a first contact blade connected to the needle carriage; and
a second contact blade secured within the housing;
wherein said needle carriage and said contact blades are oriented
such that when said needle carriage is rotated from the loading
position to the cut-off position, the first and second contact blade
each contact the needle.
2. The apparatus of claim 1 wherein the first and second contact
blades sever a portion of the needle when the needle carriage is
rotated to the cut-off position.
3. The apparatus of claim 2 further comprising a waste compartment
located within the housing for receiving the severed portion of
the needle, the upper portion of the waste compartment having an
opening located generally beneath the needle carriage.
4. The apparatus of claim 3 further comprising a door connected
to the needle carriage, wherein said door is of a dimension to cover
the opening to the waste compartment when the needle carriage is
in the loading position.
5. The apparatus of claim 4 wherein said door does not cover the
opening to the waste compartment when the needle carriage is in
the cut-off position.
6. The apparatus of claim 1 wherein the second contact blade prevents
the movement of a portion of the needle, thus causing bending of
the needle when the needle carriage is rotated from the loading
position to the cut-off position.
7. The apparatus of claim 1 further comprising:
an electrically conductive contact strip secured to the housing
such that the first contact blade contacts the contact strip when
the needle carriage is in the cut-off position; and
a battery, the first terminal of which is connected to the contact
strip and the second terminal of which is connected to the second
contact blade.
8. The apparatus of claim 7 wherein the battery provides sufficient
current to melt a portion of the needle when the needle carriage
is in the cut-off position.
9. The apparatus of claim 1 further comprising a torsion spring
connected to the housing, wherein the torsion spring provides pressure
against the needle carriage to maintain the needle carriage in the
loading position in the absence a rotational force applied to the
needle carriage.
10. The apparatus of claim 1 wherein the needle carriage includes
a port for receiving the neck and shoulder portions of a syringe.
11. The apparatus of claim 1 wherein the angular distance between
the loading position and the cut-off position is approximately 60
degrees.
12. A method for removing the needle portion of a syringe, comprising
the steps of:
(a) inserting a needle into a needle carriage in a loading position,
the needle carriage being rotatably connected to a housing;
(b) rotating the needle carriage from the loading position to a
cut-off position;
(c) causing a first contact blade and a second contact blade to
contact the needle when the needle carriage is in the cut-off position;
(d) causing an electrical current to pass through the first contact
blade, the needle, and the second contact blade to melt the needle;
and
(e) severing a portion of the needle with the first and second
contact blades.
13. The method of claim 12 further comprising the step of retaining
the severed portion of the needle in a waste compartment.
14. The method of claim 13 wherein the opening to the waste compartment
is covered by a door connected to the needle carriage when the needle
carriage is in the loading position and is not covered by the door
when the needle carriage is in the cut-off position.
15. The method of claim 12 wherein, during the rotating step, the
second contact blade prevents the movement of a portion of the needle,
thus causing bending of the needle when the needle carriage is rotated
from the loading position to the cut-off position.
16. The method of claim 12 wherein the electrical current is provided
by a battery, the first terminal of which is connected to a contact
strip that contacts the first contact blade when the needle carriage
is rotated to the cut-off position and the second terminal of which
is connected to the second contact blade.
17. The method of claim 12 wherein the needle carriage includes
a port for receiving the neck and shoulder portions of a syringe.
18. The method of claim 12 wherein the angular distance between
the loading position and the cut-off position is approximately 60
degrees.
19. The method of claim 12 wherein the inserting step includes
inserting the syringe needle into a port in the needle carriage
such that the neck and shoulder portions of the syringe contact
the port.
20. The method of claim 19 wherein the rotating step is performed
by exerting downward pressure on the needle carriage through the
neck and shoulder portions of the syringe.
Syringe needle description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application
Ser. No. 60/006575 filed Nov. 13 1995.
TECHNICAL FIELD
This invention relates to a method and apparatus for destroying
the needle portion of a syringe. In particular, the present invention
relates to a method and apparatus that heats, sterilizes and severs
the needle portion of a syringe after the needle has been used on
a patient.
BACKGROUND OF THE INVENTION
The threat of infectious diseases, in particular AIDS and hepatitis
B, is very prevalent today in hospitals and doctors' offices as
a result of the use of hypodermic syringes. The Centers for Disease
Control in Atlanta has extensively studied accidental syringe sticking
incidents and have logged where most of the accidents occur and
to whom. The Centers' records indicate that nurses experience more
incidents than most other medical personnel.
Recovering the needle with the plastic tip cover provided with
the syringe after use has not solved the problem because the cover
can slip off or a person can be stuck by merely attempting to place
the cover on the needle. Other means presently utilized for the
disposal of used syringes still leave the steel of the hypodermic
needle on the syringe, thereby exposing the waste handlers to the
possibility of being pricked. The present syringe disposal systems
are also very expensive.
The prior art includes the apparatus disclosed in U.S. Pat. No.
4628169 which describes an apparatus for melting only the tip
of the needle, with the remainder of the metal on the syringe being
detached by a separate operation. The remaining metal portion may
still be contaminated. That system still leaves the possibility
of the person collecting the remaining needle portion being exposed
to microorganisms. Also, any infectious fluids are still available
to flow out of the now-open plastic portion of the syringe.
U.S. Pat. No. 4877934 discloses a needle destroying apparatus
which utilizes converging electrodes. The hypodermic syringe is
inserted into the apparatus in a vertical orientation and is either
slid onto a bottom electrode ramp or an electrode that can slide
toward the bottom electrode thereby destroying the needle. However,
because of the vertical orientation of the needle as it is inserted
into the apparatus, the burnt needle tends to bend away from the
ramp and loses contact with the bottom electrode. In addition, because
of the vertical orientation, the burnt needle tends to collect on
the bottom electrode thereby fouling the surface of the bottom electrode.
What is needed is a needle destruction apparatus that is easy to
operate and will reliably destroy the needle efficiently. What is
further needed is an apparatus that can be used in the clinic that
can be used for long periods of time before it has to be taken apart
and cleaned. An apparatus is needed that will treat used syringes
to prevent storage of live viruses and other microorganisms in unsealed
containers at room temperature, causing unwanted aerosol vapor to
contaminate room air breathed by health care workers and patients.
SUMMARY OF THE INVENTION
The present invention is an apparatus for destroying a syringe
needle comprising a housing and a rotating needle carriage that
receives a needle in a loading position. The needle carriage is
rotated downwardly to a cut-off position. At the cut-off position,
two opposing contact blades pinch the needle, which electrically
connects the positive and negative terminals of a battery. Current
flows through the contact blades and the needle, thereby melting
the needle. A slight further rotation of the needle carriage causes
the contact blades to sever a portion of the needle. The severed
portion of the needle then falls into a waste compartment in the
bottom of the housing. When the remainder of the needle is removed
from the needle carriage, the needle carriage rotates upwardly and
returns to the loading position.
It is, therefore, an object of the present invention to provide
a safe, low cost, efficient and easy to use device for sterilizing
and destroying the metal needle of a hypodermic syringe, thereby
killing any infectious microorganism that may be present in or on
the needle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the present invention.
FIG. 2 is a side view in partial cross-section of the device of
FIG. 1.
FIG. 3 is a top view of the device of FIG. 1.
FIG. 4 is a front view of the device of FIG. 1.
FIG. 5 is a perspective view of a first alternative embodiment
of FIG. 1.
FIG. 6 is a partial cross-section view of the device of FIG. 5.
FIG. 7 is a perspective view of a second alternative embodiment
of the present invention.
FIG. 8 is an enlarged view of a portion of the device of FIG. 7.
FIG. 9 is a cross-sectional view of a third alternative embodiment
of the present invention.
FIG. 10 is an enlarged exploded view of a portion of the device
of FIG. 11.
FIG. 11 is a perspective view of a fourth alternative embodiment
of the present invention.
FIG. 12 is a cross-sectional view of the device of FIG. 11.
FIG. 13 is a partial cross-sectional view of a fifth alternative
embodiment of the present invention, with part of the housing removed
for detail.
FIG. 14 is a front view of the device of FIG. 13.
FIG. 15 is a partial cross-sectional view of the device of FIG.
13 with the needle carriage in the loading position.
FIG. 16 is partial cross-sectional view of the device of FIG. 13
with the needle carriage in the cut-off position.
DETAILED DESCRIPTION
The present invention is a method and apparatus for destroying
the needle portion of a hypodermic syringe. The present invention
is, in part, an apparatus that is capable of simultaneously sterilizing
and destroying the needle portion of a hypodermic syringe and thereby
eliminating the risk of infection by a microorganism that may be
present in or on the needle.
When a syringe is inserted into the apparatus described herein,
the needle is heated to a temperature of at least 1750.degree. C.
This temperature is capable of inactivating any virus, bacteria,
yeast or other microorganism. In addition to being heated, the needle
is melted so that it is removed from the remaining portion of the
syringe. The nub remaining after the needle is melted and sealed
so that no fluid can leak from the syringe.
Referring now to FIGS. 1 through 4 the numeral 10 denotes generally
the present invention which comprises a housing 12 a burning chamber
14 and waste collection means 16. The housing 12 can be made of
any suitable material, such as metal, plastic or the like so long
as the material is capable of maintaining structural integrity if
exposed to sparks caused by the melting needle. The housing 12 is
generally defined with side surfaces 18 end surfaces 20 a top
surface 22 and a bottom surface 24. It is to be understood that
the apparatus according to the present invention can be mounted
to a wall or a surface such as the bottom of a wall cabinet or set
on a counter.
The burning chamber 14 occupies the forward end of the housing
12 and preferably is constructed of a heat resistant material. The
burning chamber 14 is defined by side chamber walls 25 a chamber
top 26 rear chamber wall 28 front chamber wall 30 and a preferably
non-vertical front face wall 32. A first electrical contact 33 is
mounted on the front face wall 32. As seen more clearly in FIG.
2 the first electrical contact 33 is a conical shaped port 40 which
is mounted to the front face wall 32 of the burning chamber 14 by
means of screws 5. The first electrical contact 33 is connected
by wire 51 to a battery 78. The port 40 tapers downwardly in the
outer center surface and has an opening 37 disposed therethrough.
The port 40 and opening 37 are dimensional to receive the metal
needle portion 42 the neck portion 44 shoulder portion 46 and
body portion 48 of a hypodermic needle 50.
A second electrical contact is a block 53 mounted within the burning
chamber 14 to the rear chamber wall 28 and top 26 by means of mounting
brackets 55 and screws 57. The block 53 is rectangular in shape
with its lower surface 54 aligned perpendicular with the front face
wall 32. The centerline of the lower surface 54 is coaxial with
the centerline of the opening 37 of the port 40. Wire 52 connects
the block 53 with the electrical circuitry within the housing 12
through rear chamber wall 28. The block 53 is preferably made of
carbon.
The diameter of opening 37 can be of such size as to accept conventional
22-, 18-, 14- or any other gauge stainless steel needles therethrough.
Additionally, the device 10 may incorporate a plurality of needle
receiving means so that a single device 10 may be used to destroy
a number of different style and diameter needles, such as, for example,
intravenous, butterfly and catheter placement needles.
The optional waste collection means 16 is disposed beneath and
in communication with the burn chamber 14 and comprises a tray 70
that is slidably removable from housing 12 as shown in FIG. 2.
The tray 70 receives therein the melted needles that result from
the operation of the device 10.
The tray 70 is retained within the housing 12 by means of a locking
arm 72 that is operatively connected to the keylock 74. The keylock
74 is a safety feature, ensuring that only authorized personnel
open the device 10. By turning a key (not shown), the user turns
the key lock 74 and releases the locking arm 72 and allows the tray
70 to be removed.
A toggle switch 75 is mounted to the front face 32 of the housing
12. An LED light 76 is also positioned on the front face 32 and
when switch 75 is moved to the "ON" position the light
is illuminated. The power source is normally a 12-volt battery 78
that is rechargeable through charging opening 80 in side surface
18. The battery 78 is housed on the rear of the burning chamber
14 and is contained by rear chamber wall 28 battery side walls
85 battery rear wall 87 battery top wall 88 and battery bottom
wall 89. A second LED light, not shown, may be provided to indicate
that the charging circuit is in use. A conventional breaker can
be used in place of the fuse.
An electric fan 60 shown in FIG. 5 is mounted to one of the side
chamber walls 25 adjacent to the tray 70. Wire 51 connects the
fan with the electrical circuitry within the housing 12 through
the rear chamber wall 28. Thus, the fan is activated when the switch
75 is moved to the "ON" position.
Operation
To operate the device 10 the user flips the switch 74 to the "ON"
position, which in turn allows electricity to flow from battery
78 to the first electrical contact 33 and to block 53. The light
76 will also be illuminated, indicating that the device 10 is operative.
The fan 60 will also be energized.
The user inserts the needle 50 into the port 40 until the shoulder
46 engages the port. When the length of the needle 50 is enclosed
within the burning chamber 14 the user causes the length of the
needle to contact the block 53. Because the shoulder portion 46
is in contact with the first electrical contact 33 the needle portion
42 then acts as a jumper between contact 33 and block 53 closing
the circuit and melting the needle portion 42. The majority of the
metal needle portion 46 melts off of the needle 50 and falls into
the tray 70.
Once the needle 50 is sealed, the user withdraws the needle 50
from the device 10. Another needle 50 may be inserted into the device
10 or the device 10 can be de-energized by turning the switch 75
to the "OFF" position. The light 76 will then go off,
indicating that the device 10 is inoperative.
Waste material in tray 70 can be removed by turning the keylock
74 to the "UNLOCK TRAY" position. The contents of the
tray 70 are sterile, so they can be disposed of as normal waste
materials. The tray 70 will contain no contaminated metal so incidents
of infection will be eliminated. The remaining body portion 48 of
the needle 50 can be recycled as sterilized plastic.
First Alternative Embodiment
As seen more clearly in FIGS. 5 and 6 the first alternative embodiment
is similar to the device shown in FIGS. 1 through 4 except that
the first electrical contact 33 is mounted on the front face wall
32 of the burning chamber 14 and comprises a fixed plate 36. A sliding
plate 38 is in sliding relation within the fixed plate 36. A conical
shaped port 40 is threadably mounted on the sliding plate 38. The
port 40 tapers downwardly through the sliding plate 38 which exits
the face of fixed plate 36. The fixed plate 36 has an opening 37
centrally disposed therethrough. The port 40 and opening 37 are
dimensional to receive the metal needle portion 42 the neck portion
44 shoulder portion 46 and body portion 48 of a hypodermic needle
50. Wire 51 connects the fixed plate 36 with the electrical circuitry
within housing 12 through rear chamber wall 28.
The second electrical contact 52 is a block 53 and is structured
in the same manner described above for the device shown in FIGS.
1 through 4.
In operation, the first alternative embodiment operates initially
similar to the embodiment described above. To operate the device
10 the user flips the switch 74 to the "ON" position,
which in turn allows electricity to flow from battery 78 to the
first electrical contact 33 and to block 53. The light 76 will also
be illuminated, indicating that the device 10 is operative. The
fan 60 will also be energized.
The user inserts the needle 50 into the port 40 until the shoulder
46 engages the port. When the length of the needle 50 is enclosed
within the burning chamber 14 the user causes the length of the
needle to contact the block 53. Because the shoulder portion 46
is in contact with the first electrical contact 33 the needle portion
42 then acts as a jumper between contact 33 and block 53 closing
the circuit and melting the needle portion 42. The majority of the
metal needle portion 46 melts off of the needle 50 and falls into
the tray 70.
To seal off any remaining portion of the needle, the user moves
the body of the syringe upwardly while shoulder 46 of the needle
is flush against the port. This upwardly motion causes the sliding
plate 38 to slide within the fixed plate 36. Any remaining metal
on the needle 50 seals as it contacts solid surface of the fixed
plate 36 above the opening 37 and seals the needle. While in operation,
the optional fan 60 draws any unpleasant odors and smoke resulting
from the molten metal out of the burn chamber and disperses the
odors through a filter into the atmosphere.
Second Alternative Embodiment
A second alternative embodiment is shown in FIGS. 7 and 8. In lieu
of the first electrical contact being an opening 37 on a sliding
plate 38 it is contemplated that alternatively the first electrical
contact comprise a pair of opposed, spring-loaded cylinders 90.
Each of the cylinders 90 is mounted within a cylinder housing 91.
The cylinder housing 91 has a chamber 92 that receives a spring
93 and the pin 90. The cylinder housings 91 are mounted in opposed
relation to each other to the front face wall 32. Wires 56 58 connect
the cylinders 90 with the electric circuitry within the housing
12 through the rear chamber wall 28. The electric contact is made
when pins contact the needle as it passes through the opening 37
and into the burning chamber 14.
Third Alternative Embodiment
A third alternative embodiment is shown in FIG. 9. The third alternative
embodiment is similar to the preferred embodiment discussed above
except for the opening 37. It is contemplated that the opening 37
may be dog-legged. The alternative embodiment in FIG. 9 has a port
40 and a stepped channel 95. The channel 95 has a first length 96
connected to a second parallel length 97. The lengths 96 97 are
not coaxial. When the needle 50 is inserted in the port 40 the
needle must pass through both lengths of the channel thus better
ensuring electrical contact at that point. It must be noted that
the degree of offset between the first 96 and second 97 lengths
of the channel 95 cannot be greater than the channel diameter. This
is to enable the needle 50 to pass through the channel 95 in a direction
substantially perpendicular with the front face wall 32 and to enable
the length of the needle to contact the second electrical contact
52.
Fourth Alternative Embodiment
A fourth alternative embodiment is shown in FIGS. 11-13. This alternative
embodiment is directed to the bending of the remaining needle after
that majority of its length has melted. The fourth alternative embodiment
is similar to the preferred embodiment in that it has a housing
12 second electrical contact 52 burning chamber 14 and battery
78.
The fourth alternative embodiment however has a different mechanism
for receiving the needle and for finishing the needle butt at the
end of the melting process. The fourth alternative embodiment includes
an inner disc 100 threadably mounted to the front face wall 32 of
the burning chamber 14. An axle 101 extends outwardly from the center
of the face of the inner disc 100. Two pins 102 extend outwardly
from opposite halves of the face of the inner disc 100. A kidney
shaped hole 103 is cut from the inner disc 100. An outer disc 104
is rotatably mounted on the inner disc 100 by means of the axle
101. An inner sleeve 105 is fixedly mounted to the inner surface
of the outer disc 104. The kidney shaped piece 103 receives the
inner sleeve 105 and enables the inner sleeve to rotate over a limited
distance. A cup 106 is mounted to the outer surface of the outer
disc 104. The cup supports and receives the syringe shoulder while
the needle is inserted into the burning chamber 14. A pair of small,
kidney shaped openings 107 are located on opposite halves of the
inner face of the outer disc 104. The openings 107 receive the pins
102 mounted to the inner disc. The pins 102 provide support and
enable the outer disc to rotate over a limited distance relative
to the inner disc 100100. The distance of rotation for the outer
disc 104 is defined by the arc in the openings 107 and the kidney
shaped piece 103.
In operation, the needle 50 is inserted and melted as discussed
above for the preferred embodiment. After most of the length of
needle has melted, any remaining needle is sealed by rotating the
outer disc 104. This causes the needle 50 to bend as it contacts
the outer surface of the inner disc 100.
It is to be understood that an important part of the present invention
is preferred that the needle be inserted in a non-vertical orientation.
The angle from the vertical can be between 10.degree. and 90.degree.
with the more preferred angle range of between 20.degree. and 75.degree.
with the most preferred angle range of approximately 45.degree..
It will be appreciated that the embodiments discussed above are
the preferred embodiments, falling within the scope of the appended
claims, and that various other alternative embodiments are contemplated.
For example, the angle of the front face wall 32 may be altered
to accommodate the user. Moreover, it is contemplated that the battery
78 may be stored below the burning chamber 14 for wall-mounted units.
Fifth Alternative Embodiment
A fifth alternative embodiment of the present invention is described
below with reference to FIGS. 13-16. In general, this alternative
embodiment includes a rotating needle carriage that receives a needle
in a loading position. The needle carriage is rotated downwardly
to a cut-off position. At the cut-off position, two opposing contact
blades pinch the needle, which electrically connects the positive
and negative terminals of a battery. Current flows through the contact
blades and the portion of the needle between the contact blades,
thereby melting the needle and severing the metal needle from the
syringe. The severed portion of the needle then falls into a waste
compartment under the contact blades. When the syringe is removed
from the needle carriage, the needle carriage rotates upwardly and
returns to the loading position.
The apparatus 200 of this alternative embodiment of the present
invention is shown in FIG. 13. The apparatus includes a housing
201. The housing preferably includes an essentially flat bottom
surface 202 thus allowing the apparatus to be placed upright on
a table, countertop, or other similar surface. As is shown in FIG.
14 located near the upper portion of the apparatus are a left upper
side wall 203 and a right upper side wall 204. A waste compartment
207 generally comprising a hollow chamber, is located within the
housing. The upper portion of the waste compartment 207 is defined
by an opening 208. A needle carriage, generally shown at 210 in
FIG. 13 is rotatably connected between the upper side walls 203
and 204.
The needle carriage 210 includes a generally convex outer surface
212. Pins 214 rotatably connect the needle carriage to the upper
side walls 203 and 204. A port 215 for receiving a needle is provided
in the needle carriage 210. At the outermost edge of the port 215
i.e., where the port intersects the convex outer surface 212 of
the needle carriage, the port includes a wide opening 215a (FIG.
14). The wide opening 215a of the port 215 allows the port to accept
the neck and shoulder portions of a hypodermic syringe. The port
tapers to a smaller opening 215b (FIG. 14) dimensional to receive
the metal needle portion of a hypodermic syringe.
The needle carriage 210 includes an integrally formed carriage
arm 216. The carriage arm 216 extends from the port 215 toward the
rear of the housing 201. A door 218 is connected to the needle carriage
210 and is situated generally opposite the port 215. The door 218
is of a dimension as to entirely cover the opening 208 to the waste
compartment 207 when the needle carriage is in the loading position
shown in FIG. 13 and FIG. 15.
Also attached to the needle carriage is a first contact blade 220.
The first contact blade 220 is formed of electrically conductive
material and is secured to the lower end of the needle carriage
210 preferably by screws 222. Any other suitable means of securing
the first contact blade 220 to the needle carriage 210 may be utilized
instead of screws. The first contact blade 220 includes an outer
edge 220a that extends toward the outer surface of the needle carriage.
The first contact blade 220 also includes an inner, sharpened edge
220b that extends inwardly, away from the outer surface of the needle
carriage 210.
A contact strip 224 made of electrically conductive material,
is connected to a portion of the housing 201 below the needle carriage
210. The contact strip 224 is located on the housing 201 in such
a manner as to allow edge 224a of the contact strip to be contacted
by the outer edge 220a of the first contact blade 220 when the needle
carriage 210 is rotated downwardly, as shown in FIG. 16. The contact
strip 224 is electrically connected to a first terminal of a battery
(not shown) located within the housing 201.
A second contact blade 230 is located within the upper portion
of the housing 201. The second contact blade 230 is made of electrically
conductive material and is fixedly secured within the housing 201
in a generally vertical orientation. The lower edge 230a of the
second contact blade 230 has a sharpened edge. The second contact
blade 230 is electrically connected to a second terminal on the
battery (not shown). The second contact blade 230 has a slot (not
shown) therein through which one end of a torsion spring 236 may
be situated. The location and orientation of the torsion spring
236 is shown in FIG. 15. The other end of the torsion spring 236
is fixedly secured within the housing 201. The torsion spring 236
provides constant pressure against the second contact blade 230
to maintain the needle carriage 210 in the loading position in the
absence of any downward pressure. Connected near the upper edge
of the second contact blade 230 is a carriage stop 232.
In operation, a hypodermic syringe is inserted, needle-first, into
the port 215 in the needle carriage 210 with the needle carriage
at the loading position, as shown in FIG. 15. The needle is fully
inserted until the neck and shoulder portions of the syringe contact
wide opening 215a of the port 215 and can be inserted no further.
When the needle is fully inserted, the needle passes between the
sharpened edges 220b, 230a of the first and second contact blades
220 and 230 respectively.
With the needle remaining fully inserted, the syringe is moved
downward so that the needle carriage 210 is rotated downwardly to
the cut-off position, seen in FIG. 16. Preferably, the angular distance
between the loading and cut-off positions is approximately 60 degrees.
The torsion spring 236 applies pressure on the needle carriage 210
to maintain it in the loading position. However, rotation of the
needle carriage 210 is caused when sufficient downward pressure
is exerted on the needle carriage to overcome the resistant force
exerted by the torsion spring 236. Downward pressure is exerted
on the needle carriage 210 through the neck and shoulder portions
of the syringe by the person holding the syringe in the port. As
the needle carriage is rotated downwardly, the needle is prevented
from rotating by contact with the sharpened edge 230a of the second
contact blade 230. Thus, the metal portion of the needle is bent
near the base of the needle, as seen in FIG. 16.
When the needle carriage is rotated downwardly to the cut-off position,
as seen in FIG. 16 the outer edge 220a of the first contact blade
220 contacts the contact strip 224 and the inner, sharpened edge
220b of the first contact blade 220 contacts the needle. Therefore,
when the needle carriage is rotated to the cut-off position, an
electrical circuit is formed by the battery (not shown), the contact
strip 224 the first contact blade 220 the metal needle, and the
second contact blade 230. Electrical current flowing from the battery
through the circuit is of such an amperage as to melt the metal
portion of the needle between contact blades 220 and 230. A slight
additional downward rotation of the needle carriage 210 causes the
sharpened edges of the first and second contact blades to pinch
the metal needle, shearing the needle at the pinch point.
When the needle carriage 210 is rotated to the cutoff position
shown in FIG. 16 the door 218 is rotated away from the opening
208 to the waste compartment 207. Therefore, when the melted metal
needle is sheared by the first and second contact blades, the severed
portion of the needle falls downwardly, through the opening into
the waste compartment.
After the needle is melted and severed at the pinch point, the
hypodermic syringe is removed from the port 215 in the needle carriage
210. Removing the syringe from the needle carriage removes the downward
pressure on the needle carriage. With no downward pressure on the
needle carriage, the torsion spring 236 exerts an upward force on
the needle carriage. The torsion spring therefore causes the needle
carriage 210 to rotate upwardly to the loading position. Rotation
of the needle carriage 210 is halted at the loading position by
the carriage stop 232 which contacts the carriage arm 216 to prevent
any further upward rotation of the needle carriage. When the needle
carriage 210 is at the loading position, the door 218 is situated
over the opening 208 to the waste compartment 207 thereby ensuring
that the severed needles remain in the waste compartment.
From the foregoing it will be appreciated that the disclosed embodiments
of the present invention overcome the drawbacks of the prior art
described hereinabove. From the description of the embodiments herein,
equivalents of the elements shown therein will suggest themselves
to those skilled in the art and way of constructing other embodiments
of the present invention will suggest themselves to practitioners
of the art. Therefore, the scope of the present invention is to
be limited only by the claims below. |