Syringe with retractable needle

A medical instrument comprises a needle which is movable between an extended operative position where the needle is exposed for use and a retracted inoperative position where the needle is covered so as to reduce the likelihood of inadvertent contact with the needle. The instrument also includes a needle biasing means which normally urges the needle toward its retracted position and an actuator movable between a position of interference with movement of the needle to its retracted position and a position out of interference with the needle to permit the needle biasing means to act on the needle and urge the same toward its retracted position.

FIELD OF THE INVENTION 
The present invention relates in general to new and useful improvements in 
medical instruments having needles, and more particularly to medical 
instruments with needles wherein the needles are retractable into housings 
of the instruments after use thereby decreasing the risk of inadvertent 
contact with the needles by medical and waste-disposal personnel. 
BACKGROUND OF THE INVENTION 
A number of instruments are currently used for various forms of 
venepuncture and subcutaneous and intramuscular injection. 
For example, a medical instrument commonly referred to as a "syringe" 
comprises a cylindrical receptacle carrying a piston, and a needle with a 
hub threadably mounted on an end of the receptacle. So mounted, the needle 
is fixed in place relative to the receptacle. The syringe is most often 
used for drawing blood and for providing subcutaneous and intramuscular 
injections. 
Another medical instrument, termed a "vaccutainer," is primarily used to 
take multiple samples of blood. A syringe, as stated above, can also be 
used to sample blood. However, a syringe is only suited to draw a single 
sample of generally no more than 20 cc of blood. Oftentimes, it is 
necessary to take multiple blood samples, for example, when a multiplicity 
of blood tests must be performed on a patient. A vaccutainer can be used 
to take multiple blood samples upon a single puncture of the patient, 
thereby reducing patient stress which would otherwise result from the use 
of syringes and multiple punctures. 
The vaccutainer includes a needle attached to a plastic receptacle. Both 
ends of the needle are exposed. One end is adapted to be inserted into a 
patient's vein. The other end is adapted to be inserted through a rubber 
stopper capping a vacuum-sealed glass tube. Upon insertion of the needle 
through the stopper, blood is drawn from the vein into the tube. When the 
tube is filled with blood, the tube is removed from engagement with the 
needle and replaced with another vacuum-sealed tube. In this manner, 
multiple sample tubes of a patient's blood may be obtained upon a single 
puncture. 
In addition, an instrument known as a "butterfly needle" consists of a 
needle which is continuous at one end of the needle with a thin diameter 
rubber tubing. The tubing is adapted to be attached to a syringe, a 
vaccutainer tube, or any one of a variety of other collection receptacles. 
The free end of the needle is adapted to be inserted into a patient. The 
needle carries a plastic fitting having a pair of oppositely projecting 
"wings" for use in guiding the needle, hence the name "butterfly." The 
butterfly needle and its associated tubing and receptacle are most often 
used for collecting blood. 
A further example of a medical instrument, termed an "I.V. (intravenous) 
catheter" is generally used for administering replacement fluids, such as 
saline solutions, lactated ringer's solution, dextrose water solutions and 
blood by transfusion. 
The I.V. catheter consists of an I.V. placement unit comprising a needle 
having permanently affixed on one end thereof a plastic handle. A thin 
plastic sheath having its own plastic handle slidably receives the needle. 
The sheath extends substantially the entire length of the needle. In use, 
once the needle with surround sheath have been inserted into a patient's 
vein, the needle is removed, leaving the sheath behind inside the vein. 
The needle with its handle is then discarded. A line of rubber tubing is 
mounted on the handle of the sheath, the free end of the rubber tubing 
being connected to an I.V. bag. 
Although the above-described medical instruments may be effective for 
performing various forms of venepuncture and subcutaneous and 
intra-muscular injections, they are associated with a common disadvantage. 
The problem arises from the lack of a safe and effective method of needle 
removal and disposal, a problem with which medical institutions, medical 
personnel, waste disposal personnel and others have become acutely aware 
as a result of the relatively recent heightened publicity surrounding 
Hepatitis and the uniformly-fatal disease, "Aquired Immune Deficiency 
Syndrome (AIDS)." 
Several methods of needle disposal are currently used in medical 
environments, none of which have been demonstrated as being sufficiently 
safe for medical personnel and waste removal workers, as each of these 
methods may result in inadvertent contact or puncture by a contaminated 
needle. 
One method of contaminated need disposal requires transportation of, for 
example, a syringe with attached contaminated needle to a cardboard 
"needle box" and cutting the needle over the box with a clipper to thereby 
detach the needle from the syringe proper, the needle then dropping into 
the box. This method has been demonstrated to be ineffective due to the 
danger of micro-aerosol spray when the needle is clipped. Moreover, there 
exists an inherent danger in carrying the exposed needle to the box, as 
well as disposing of a box filled with contaminated needles. In addition, 
contaminated needles invariably slip out of the box through seams at 
folded edges of the paperboard box, and thus present a further danger. 
Other dirty needle boxes are currently used. For example, a plastic bucket 
with hinged lid is commonly in use. Although use of this box eliminates 
the possibility of leakage of contaminated needles from the box, as there 
are no open seams through which the needles can pass. However, the 
inherent dangers associated with carrying needles to the box and 
micro-aerosol spray (if needles are cut) remain. 
Other methods of disposing of contaminated needles consist of either (1) 
throwing the entire syringe or other like medical instrument with the 
needle attached thereto into a needle box, or (2) recapping the needle, 
removing it from the syringe proper, and throwing it into a box. The 
latter method is the most dangerous. However, in either case, transporting 
a capped or uncapped needle to a designated container has proven to be 
both cumbersome and a constant health hazard to both medical institutions 
and medical and other personnel. 
Further, needles are inadvertently thrown into regular waste bins. This 
poses a constant danger to housekeeping personnel as well as contributing 
to increased insurance costs of medical institutions. 
Therefore, it is obvious that, until the use of needles becomes obsolete, 
methods and devices directed to reducing the likelihood of inadvertent 
contact with contaminated needles must be developed. 
It has thus been desirable to provide a medical instrument of the type 
described below in detail comprising a needle which is retractable with 
respect to the medical instrument so as to reduce the likelihood of 
accidental contact of personnel with the needle after its use. 
SUMMARY OF THE INVENTION 
According to the present invention, a medical instrument comprises a needle 
and a means for mounting the needle for movement between an extended 
operative position relative to the medical instrument where the needle is 
exposed for use and a retracted inoperative position where the needle is 
covered so as to reduce the likelihood of inadvertent contact with the 
needle. 
The mounting means comprises support means, needle biasing means, actuating 
means and actuator biasing means. 
The support means mounts the needle between its extended and retracted 
positions. The needle biasing means is interposed between the support 
means and the needle and normally urges the needle to its retracted 
position. The actuating means is mounted on the support means for movement 
between inner and outer positions and is adapted to be disposed to retain 
the needle in its extended position in the inner position of the actuating 
means. The actuator biasing means is interposed between the actuating 
means and the support means and normally urges the actuating means toward 
its inner position of interference with movement of the needle to its 
retracted position. Movement of the actuating means to its outer position, 
against the biasing force of the actuator biasing means, disposes the 
actuating means out of a position of interference with the needle so as to 
permit the needle biasing means to act on the needle and dispose the same 
in its retracted position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Prior to discussing the various concepts of the invention, it is 
appropriate to review, by way of illustration, a conventional prior art 
syringe, as the embodiments of the invention to be discussed have been 
presented in the form of a syringe. It is contemplated, however, that the 
various concepts of the invention may be in the form of a vaccutainer or 
any other medical instrument of the type discussed or suggested above. 
Referring to the drawings in detail, and in particular to FIG. 1, there is 
illustrated a conventional syringe generally indicated by numeral 10. The 
syringe includes a receptacle 12, a needle unit 14, a plunger 16 and a 
cover 17. 
The receptacle 12 is a hollow cylindrical member and has formed at an upper 
end 18 thereof a lateral flange 20 extending about the receptacle. The 
flange 16 functions as a handle or grip during operation of the syringe as 
is well known by one of ordinary skill in the relevant art. A lower end 22 
of the receptacle 12 terminates in a reduced diameter portion 24 by virtue 
of inclined wall 26 of the receptacle. A transverse inner wall 28 
separates the receptacle 12 and the reduced diameter portion 24 at the 
inclined wall 26 and includes a central opening 30 extending through the 
inner wall 28. A hollow tubular portion 32 extends downwardly from the 
inner wall 28 and communicates with an interior 33 of the receptacle 12 
through the opening 30. An interior surface 34 of the reduced diameter 
portion has formed thereon a plurality of threads 36 which function to 
mount the needle unit 14 on the receptacle 12, as will be discussed below. 
The needle unit 14 comprises a hubor carrier 38 and a needle 40. The 
carrier 38 is a hollow member open at a first end 42 thereof and closed at 
a second end 43 of the carrier by wall 44. As stated above, the needle 
unit 14 is adapted to threadably mount on the receptacle 12. To this end, 
the carrier 38 includes an annular flange 46 at the first end 42 of the 
carrier and adapted to engage the threads 36 on the interior surface 34 of 
the reduced diameter portion 24 of the receptacle 12 to removably mount 
the needle unit 14 on the receptacle. 
The needle 40 is fixedly mounted on the carrier 38 at the wall 44 thereof 
in registry with a hole 48 extending therethrough. When the needle unit 14 
is mounted on the receptacle 12 in the manner described above, the needle 
40 is set in registry with the tubular member 32, the opening 30 and thus 
interior 33 of the receptacle 12. In this manner, communication of fluids 
between the needle 40 and the receptacle 12 is achieved. 
The plunger 16 includes a stem 52 carrying at one end 54 thereof a plate 
portion 56 and at the other end 57 thereof a rubber sealing portion 58. 
The plunger 16 is mounted on and within the hollow receptacle 12 and is 
moveable relative thereto in outer and inner directions, with the rubber 
sealing portion maintaining continuous sealing contact with interior wall 
60 of the receptacle 12 as the plunger 16 is moved in either of such 
directions. 
The syringe cover 17 is formed by a hollow cylindrical member which is open 
at one end 62 thereof and closed at the other end 64 of the cover. The 
cover 17 is adapted to mount on the needle unit 14 over the needle 40 and 
to this end the hollow cylindrical cover 17 has an internal diameter which 
is slightly greater than the external diameter of the carrier 38. In this 
manner, the cover 17 is adapted to slidably mount over the needle unit in 
snug-fit relationship relative thereto. 
In assembly and operation of the syringe 10 when, for example, it is 
desired to employ the syringe to draw blood from a patient, the needle 
unit 14 is mounted on the receptacle 12 in the manner described above by 
connecting the carrier 38 of the needle unit to the reduced diameter 
portion 24 of the receptacle with the annular flange 46 of the carrier 38 
being set in engagement with the threads 36 of the reduced diameter 
portion. In this manner, the needle unit 40 is fixedly mounted on the 
receptacle 12. With the plunger 16 in full registry with the receptacle 
12, the needle unit 40 is then inserted into a vein of a patient and the 
plunger is subsequently moved in the outer direction through forces 
exacted on the plate portion 56, thereby creating a vacuum within the 
receptacle and thus effecting withdrawal of blood from the patient. After 
a sufficient sample of blood has been taken, the needle 40 is withdrawn 
from the patient. The needle is then inserted into a stopper sealing a 
tube where the blood sample is stored for subsequent laboratory testing. 
The the syringe 10 is discarded. 
However, prior to discarding the syringe 10, the cap 17 may be mounted on 
the needle unit 14 in the above-described manner to cover the needle 40 so 
as to prevent inadvertent contact therewith by health care and waste 
removal workers. Alternatively, the needle may be detached by cutting the 
needle over a "dirty-needle" box in the manner discussed above. These 
methods of needle disposal, however, as stated above, are not sufficiently 
effective to avoid inadvertent contact with the contaminated needle. In 
placing the cap 17 over the needle 40, a hurried health care worker may 
incur contact with the needle. In addition, the potential danger of 
micro-aerosol spray exists when a contaminated needle is cut. 
The potential dangers that are presented by a conventional syringe result 
from the fact that the syringe employs a needle which is fixed relative to 
a receptacle of the syringe and is thus in a position to be contacted 
inadvertently by health care and waste removal workers after use of the 
instrument. 
To reduce the likelihood of inadvertent contact with the contaminated 
needle by health care and waste disposal workers, the medical instrument 
according to the present invention employs a needle which is attached to 
the instrument and exposed when is use, but which is adapted to be set in 
a retracted position after its use with respect to the instrument so as to 
reduce the likelihood of accidental contact of personnel with the needle. 
As stated above, the various concepts of the invention are shown and 
described as being embodied in the form of a syringe. However, it is to be 
understood that such concepts may also be in the form of a vaccutainer or 
other medical instrument effective for performing various forms of 
venepuncture and subcutaneous intramuscular injections. 
Referring specifically to FIGS. 2 and 3, the medical instrument in 
accordance with the invention comprises a syringe generally indicated by 
reference numeral 66. Only a lower end 68 of the syringe is shown, an 
upper end of the syringe 66 being substantially identical to that 
illustrate in FIG. 1. 
The syringe 66 generally comprises a receptacle portion 70, a needle 72 
mounted on the receptacle portion for movement in outer and inner 
directions between extended and extracted positions, needle biasing means 
74 for normally urging the needle toward the retracted position, an 
actuator 76 mounted on the receptacle portion for movement in an inward 
direction to a position of interference with inner movement of the needle 
and an outward direction to a position out of interference with such 
movement of the needle, and an actuator biasing means 78 for normally 
urging the actuator in its inward direction. 
Specifically, the receptacle portion 70 is preferably a hollow cylindrical 
member terminating at a lower end 80 thereof in a reduced diameter portion 
82 by virtue of inclined receptacle wall portion 84. The reduced diameter 
portion 82 is preferably a substantially solid member which functions as a 
support for the above-stated needle 72, the needle biasing means 74, the 
actuator 76 and the actuator biasing means 78, as will be discussed in 
detail below. Accordingly, the reduced diameter portion 82 will 
hereinafter sometimes be referred to as "support means." 
The reduced diameter portion 82 is provided with a first stepped 
cylindrical bore 86 extending therethrough along a central longitudinal 
axis of the receptacle portion 70. The first stepped bore 86 includes 
relatively large diameter upper bore 88, a relatively small diameter lower 
bore 90, and an intermediate bore 92 positioned between the upper and 
lower bores and having a diameter intermediate in size relative to the 
diameters of the upper and lower bores. The upper, intermediate and lower 
bores 88, 90, 92 are of a size to receive the needle 72, the diameter of 
the lower bore 90 being slightly greater than that of the needle. 
As shown in detail in FIG. 3, a inner wall 132 of the reduced diameter 
portion 82 which defines the intermediate bore 92 has extending therefrom 
a plurality of first flanges 134. The first flanges extend radially about 
the first inner wall 132 and are positioned adjacent lower bore 90. Each 
of the first flanges 134 is substantially in the shape of a right 
triangle, with a small leg 136 of the triangular flange being disposed 
normal to the inner wall 132 and a hypotenuse 138 of the triangle first 
flange extending at an acute angle relative to the inner wall. As 
discussed below in detail, the first flanges 134 function in connection 
with the needle biasing means 74. 
The reduced diameter portion 82 is also provided with a second-stepped bore 
94, a central longitudinal axis of which extends along a transverse axis 
of the receptacle portion 70 which is normal to the longitudinal axis of 
the first-stepped bore 86. The second stepped bore 94 communicates with 
the upper bore 88 of the first-stepped bore 86. The second stepped bore 94 
includes a relatively-small diameter inner bore 96 and a relatively large 
diameter outer bore 98. The second stepped bore 94 is of a size to receive 
the actuator 76, the diameter of the inner bore 96 being slightly greater 
than that of the actuator as discussed below in detail. 
As shown in FIGS. 2 and 4, a plurality of second flanges 100 extend 
outwardly from another inner wall 102 of the reduced diameter portion 82 
defining the outer bore portion 98 of the second stepped bore 94. The 
second flanges 100 extend radially about the second inner wall 102 and are 
positioned adjacent outer wall 104 of the reduced diameter portion. In 
addition, like the first flanges 134, the second flanges 100 are 
substantially in the shape of a right triangle, with a small leg 106 of 
the triangular flange being disposed normal to the inner wall 102 and a 
hypotenuse 108 of the triangular flange extending at an acute angle 
relative to the inner wall 102. As discussed below in detail, the flanges 
100 function to retain the actuator biasing means 78 within the outer bore 
98 of the second stepped bore 94. 
The receptacle portion 70 and the reduced diameter portion 82 terminating 
therefrom are preferably made of plastic of a type currently used in the 
manufacture of prior art syringes and further are integrally formed 
together by injection molding techniques also currently known. 
The needle 72 has upper and lower ends 110, 112. A first collar 114, 
disc-like in configuration, is fixedly mounted on the needle upper end. 
The collar 114 has a central opening 115 for receiving the needle 72. The 
collar is preferably made of plastic, the needle being made of metal. The 
collar 114 is secured in place relative to the needle 72 by suitable 
fastening means or by a friction mounting of the collar and the needle 
through the opening 115. 
A retainer member 144 is provided on a lower surface 146 of the first 
collar 114 and is adapted to capture a free upper end 148 of the first 
coil spring 74 which is bent so as to be disposed in parallel relationship 
to the lower surface 146 of the first collar 114. The retainer member 144 
is elongated and is positioned along a radius of the circular first collar 
114. Such position of the retainer member 144 relative to the first collar 
facilitates assembly of the first coil spring to the first collar as will 
be hereinafter discussed in detail. The retainer member 144 is preferably 
made of plastic formed integral with the first collar 114. However, it is 
contemplated that the retainer member 144 may be formed separately from 
and securely mounted to the first collar 114. 
The needle 72 is adapted to be mounted on the reduced diameter portion 82 
of the syringe 66 in an extended position of the needle, wherein the upper 
end 110 of the same is positioned in registry with the first-stepped bore 
86, the collar 114 being in registry with the upper bore 88 of the 
first-stepped bore, and the lower end 112 of the needle extending 
outwardly from the reduced diameter portion 82. From its extended 
position, the needle 72 is adapted to be urged inwardly toward its 
retracted position by the needle biasing means 78 where the needle is 
housed within the reduced diameter portion 82 and an interior 116 of the 
receptacle portion 70. 
The needle biasing means 78 is in the form of a coil spring (hereinafter 
sometimes the "first coil spring"). The first coil spring 78 is housed 
substantially within the intermediate bore portion 92 of the first-stepped 
bore 86 when the needle 72 is set in its extended position. Specifically, 
in such position of the needle 72, the first coil spring 78 is compressed 
and set in sandwiched relationship between a further inner wall 118 of the 
reduced diameter portion 82 and the collar 114, with a lower portion 119 
of the first coil spring 78 positioned below the first flanges 134. The 
first coil spring 78 normally urges the needle 72 for inward movement 
relative to the reduced diameter portion 82. The needle 72 and its biasing 
means 74 are maintained in their extended and compressed conditions by the 
actuator 76. 
The actuator 76 is in the form of a pin having an elongated shaft 120 and a 
head 122 removably mounted on a outer end 124 of the shaft. An inner 
portion 126 of the shaft carries a second collar 128. 
The actuator shaft 120 is slidably received within the second-stepped bore 
94 and is moveable therein relative to the reduced diameter portion 
between inner and outer positions. In the inner position of the actuator 
76, an inner end 130 of the shaft 120 is disposed to interfere with inward 
retracted movement of the needle 72 by directly engaging the first collar 
114. Also, in the inner position of the actuator, the second collar 128 is 
positioned closely adjacent the inner bore portion 96 of the second 
stepped 15 bore 94. In the outer position of the actuator 76, the inner 
end 130 of the shaft 120 is disposed out of a position with interference 
with inward movement of the needle 72. The head 122 of the actuator is 
adapted to facilitate movement of the actuator 76 from its inner position 
to the outer position. The second collar 128 has a diameter slightly 
smaller than that of the outer bore 98 and has a length sufficient to 
provide the actuator with stability against substantial lateral movement 
of the shaft 120 as the actuator is moved between its inner and outer 
positions. The actuator 76 is normally urged toward its inner position by 
the actuator biasing means 78. 
Like the needle biasing means 74, the actuator biasing means is in the form 
of a coil spring (hereinafter sometimes the "second coil spring"). The 
second coil spring 74 is of a diameter to slidably fit within the outer 
bore portion 98 of the second stepped bore 94 and positioned between the 
second collar 128 of the actuator and the second flanges 100 on the second 
inner wall 102. In its expanded condition, the second coil spring 78 
preferably has a length slightly greater than the distance between the 
second flanges 100 and the second collar 128 so as to suitably hold the 
actuator 76 within the second stepped bore 94 without undue lateral 
movement therein. 
Although not illustrated in the drawings, the head 122 of the actuator 76 
is removable and threadably mounted on the outer end 124 of the actuator 
shaft 120. The removable connection between the head 122 and the shaft 120 
facilitates assembly of the second coil spring 78 within the second 
stepped bore 94 as will be discussed below in detail. 
The second collar 128 and the actuator 76 are preferably integrally formed 
as a one-piece plastic member by an injection molding technique well known 
in the relevant art. 
As illustrated in FIG. 5, the syringe 66 is also provided with a cap 140, 
an end 142 of which having an inner diameter slightly greater in size than 
the outer diameter of the reduced diameter portion 82. In this manner, the 
cap 140 is adapted to slidably mount over the reduced diameter portion to 
cover the needle lower end 112. 
In assembly of the syringe 66 of the invention, to dispose the needle 72 in 
its extended outer position and the actuator 76 in its inner position to 
retain the needle in the extended position against the biasing force of 
the first spring 78, the first spring is inserted through the interior 116 
of the receptacle portion 70 and subsequently positioned in registry with 
the first stepped bore 86 of the reduced diameter portion 82 and 
specifically in registry with the intermediate bore 94 thereof, with the 
lower portion 119 of the first coil spring 78 being supported by the inner 
wall 118 of the reduced diameter portion and positioned behind the first 
flanges 134 on the inner wall 132. The upper free end 148 of the first 
coil spring 74 is positioned within the interior 116 of the receptacle 
portion 70. The slope and configuration of the hypotenuse portions 138 of 
the first flanges 132 facilitate such insertion of the first spring 78 
behind the first flanges, the first spring first deforming slightly as it 
is pushed over the flanges and then resuming it normal circular, in 
cross-section, configuration. 
The needle 72 is then inserted through the interior 116 of the receptacle 
portion 70 and through the first coil spring 74, the lower end 112 of the 
needle first, and subsequently into registry with the first stepped bore 
86, with the first collar 114 on the needle upper end 110 being disposed 
within the upper bore 90 of the first-stepped bore. This latter step in 
the assembly of the syringe 66 results in compression of the first coil 
spring 78 and sandwiching of the same between the first collar 114 and the 
inner wall 118 of the reduced diameter portion 70. It also results in 
disposition of the needle 72 in its extended outer position. The first 
collar 114 is then rotated to effect capturing of the upper free 148 end 
of the spring 74 within the retainer member 144. The first collar 114 may 
be provided with an upstanding flange (not shown) to facilitate rotation 
of the collar. As indicated above, the elongated configuration of the 
retainer member 114, along with its position on the radius of the first 
collar 114, facilitates mounting of the upper free end 148 of the first 
coil spring 74 relative to the first collar. 
While the needle 72 is retained in its extended outer position against the 
biasing force of the first coil spring 78, the actuator shaft 120, with 
the actuator head 122 threadably disconnected therefrom, is placed in 
registry with the second stepped bore 94, so as to dispose the inner end 
130 of the shaft 120 in registry with the inner bore 88 of the first 
stepped bore 86 and in a position of interference with inward movement of 
the needle 72 by engaging the first collar 114 thereof. In this position 
of the actuator 76, the second collar 128 is positioned closely adjacent 
to the inner bore portion 96 of the second stepped bore 94. 
Subsequently, the second coil spring 78 of the actuator biasing means is 
also positioned registry with the second stepped bore 94 so as to be 
disposed between the second collar 128 of the actuator 76 and the second 
flanges 100. The slope and configuration of the hypotenuse portions 108 of 
the second flanges 100 permit such insertion of the second coil spring, 
the spring deforming slightly as it is forced over the flanges. When fully 
inserted within the second stepped bore 94, the second coil spring 78 is 
fully housed within the outer bore 98 of the second stepped bore an 
substantially free from forces acting on either end thereof. The actuator 
head 122 is then threadably mounted on the actuator shaft 20. The cap 140 
is then mounted on the reduced diameter portion 82 to cover the needle 72. 
It should be noted that while the assembly of the needle 72 relative to the 
reduced diameter portion 82 has been described as being performed prior to 
assembly of the actuator 76, the actuator may be assembled prior to 
assembly of the needle. 
Subsequently, the cap 140 is mounted on the reduced diameter portion 82 so 
as to cover the exposed needle 72. 
In operation of the syringe of the present invention, after the same has 
been used for drawing blood or administering subcutaneous or 
intra-muscular injection, with the plunger retracted, the needle 72, in 
its extended outer position, remains in a position for potential 
inadvertent contact with medical or waste disposal personnel. To reduce 
the probability of this potential hazard, the needle 72 is set in its 
retracted position through manipulation of the actuator 76. Specifically, 
the actuator, through grasping and pulling of the actuator head 122, is 
drawn outwardly, against the biasing force of the second coil spring 78, 
to dispose the outer portion of the actuator in a position where it cannot 
interference with inward movement of the first collar 114 of the needle 
72. To move the actuator into a position out of such interference would 
likely require disposing the outer end 130 of the actuator shaft 120 fully 
within the inner bore 96 of the second stepped bore 94. This permits the 
first coil spring 78 to act on the first collar 114 to urge the needle 72 
toward its inner retracted position. So disposed, the needle 72 is in a 
position where inadvertent contact by medical or waste disposal personnel 
may be avoided. 
It should be noted that by virtue of the connection between the first coil 
spring 74 and the first collar 114, and interaction of the first flanges 
134 and the first coil spring, the needle 72 is retained in its retracted 
position within the interior 16 of the receptacle portion 70 to reduce the 
possibility of the needle falling from the receptacle portion should the 
interior thereof be left open. 
The cap 140 may then be mounted on the reduced diameter portion 82. 
Once again, it is pointed out that while the illustrated embodiment of the 
invention has been shown in the form of a syringe, the invention may be 
utilized in conjunction with other medical instruments such as a 
vaccutainer or other medical instruments employed for various forms of 
venepuncture subcutaneous and intra-muscular injection and administration 
of I.V. fluids. 
While the invention has been described in connection with a preferred 
embodiment, it will be understood that the invention is not limited to the 
disclosed embodiment. To the contrary, reasonable variations, 
alternatives, modifications and equivalents are possible within the spirit 
and scope of the invention as defined by the appended claims.