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United States Patent Office
Patented Apr. 15, 1958
ADJUSTABLE SYRINGE , 5
Morris Dann, Havertown, and John J. Peterson, Philadelphia, Pa., assignors to American Home Products Corporation, New York, N. Y., a corporation of Delaware
Application April 19,1955, Serial No. 502,279 10
5 Claims. (CI. 128—218)
This invention relates to an adjustable syringe, and more particularly to an injection syringe adjustable to receive a plurality of ampules or cartridge-needle units of different capacities, e. g. of 1 and 2 cc. capacity or fractions thereof respectively.
The conventional metal syringe body adapted to be used with a one-short ampule or cartridge-needle unit is designed to receive and be used with an ampule of one size only. The versatility of such a syringe can be advantageously increased by designing it to accommodate ampules of two or more different capacities.
It is an object of this invention to provide such a syringe having simple and effective means for adjusting it to be used with ampules of different capacities.
Ampules may vary in capacity by varying in diameter or in length. If they vary in diameter, difficulty is experienced in providing simple means for holding all sizes rigidly centered in the syringe body. Accordingly the present syringe is designed to be used with ampules of uniform diameter and varying length. If ampules of different lengths are used in one syringe, means must be provided to prevent the plunger being inadvertently withdrawn from the shorter ampules. This prevents not only drug loss, but also possibility of contamination. The present invention incorporates such means.
The syringes of this invention may be adapted for use with a separate ampule and injection needle or, preferably, with a cartridge-needle unit comprising a drug-filled ampule with an attached shielded needle as disclosed in Dann Patent No. 2,671,450.
Preferred embodiments of our invention are disclosed in the following description and accompanying drawings, but these are intended to be illustrative only and not to limit the scope of our invention which is defined in the appended claims.
In the drawings, Fig. 1 is a perspective view, partly cut away, of one modification of our syringe containing a cartridge-needle unit; Fig. 2 is a longitudinal section cn line 2—2 of Fig. 1; Fig. 3 is a cross section on line 3—3 of Fig. 2; Fig. 4 is a cross section on line 4—4 of Fig. 2; Figs. 5, 6, and 7 are views, partly in section, of a syringe having a modified stop; Fig. 8 is a sectional view of a syringe designed for use with ampules which are not threaded into the syringe barrel; Fig. 9 is a longitudinal sectional view of a syringe designed for use with ampules of three different sizes; and Fig. 10 is a sectional view on line 10—10 of Fig. 9.
In the drawings 1 represents the barrel of a syringe body containing a cartridge-needle unit 2. The latter consists of an ampule 3 having affixed in its distal end a sheathed injection needle 4, as illustrated in Fig. 2 of Dann Patent 2,671,450. The capacity of ampule 3 as illustrated in Figs. 1 and 2 is i cc. The barrel 1 of the syringe is extended proximally at 5 to accommodate an ampule 6 of 2 cc. capacity as illustrated in Fig. 7. Barrel 1 is provided on both sides with windows 7 and S to 'facilitate manipulation of ampules while
loading the syringe and to permit viewing of aspirated blood when necessary.
Barrel 1 is provided at its proximal end with a head 9 hinged on pivots 10 and 10', permitting the head to be swung aside for loading the syringe. Head 9 has an internal cylindrical bore 11 in which is slidably mounted sleeve 12 provided midway of its length with an internal flange 13; in the position shown in Fig. 2 this sleeve is received in the proximal end 14 of barrel 1. The head 9 is closed at its proximal end by wall 15 pierced by axial hole 16. Two opposed slots 17 and 17' are provided in the side wall of head 9 near wall 15.
A plunger rod 18 passing through hole 16 in head 9 is slidably mounted axially in syringe barrel 1. At its distal end rod 18 is provided with a flange 19 of a diameter sufficiently small to enter ampule 3, and a short internally threaded axial bore 20 adapted to mate with the threaded insert usually provided in the ampule plunger. At its proximal end rod IS is provided with a thumb piece 21 cooperating with finger pieces 22 and 22' attached to head 9 to resist opposing pressure of thumb and fingers of the user during injection.
In the modification illustrated in Figs. 1-4, rod 18 is a larger diameter 23 throughout its distal portion and of smaller diameter 24 throughout its proximal portion, except that near the thumb piece 21 it may be gradually enlarged at 23' by taper 24' to the same diameter as at 23, as shown in Fig. 2; the meeting of the two portions of different diameter near the middle of the rod is defined by shoulder 25. An adjustable locking slide 26 is slidably mounted in slots 17 and 17', the slide having an aperture through which rod 18 passes. One portion of the aperture 27 is large enough to permit the large part (23) of rod 18 to pass; the other portion of the aperture 28 is of only sufficient size to permit passage of the smaller part (24) of the rod. A helical compression spring 29 surrounds the plunger rod within head 9, one end bearing on flange 13 of sleeve 12 and the other on brass cup washer 15' which in turn bears on adjustable slide 26. This spring has a double function; it maintains sleeve 12 in the bore of the proximal end 14 of barrel 1 when the syringe is prepared for injection but permits withdrawal of the sleeve to permit swinging the head aside for loading, and it forces brass cup 15' against slide 26 thus holding the slide friction-tight against the sides of slots 17 and IT. Small protuberances 30 and 30' may be provided on slide 26 to aid in retaining it in either extended position.
The operation of the syringe illustrated in Figs. 1-4 is as follows.
If the user wishes to give a 1 cc. injection, he slides adjustable stop so that the 2 cc. indicium 31 is exposed, thus permitting the large portion (23) of rod 18 to be withdrawn through opening 27 in slide 26. By withdrawal of the rod until flange 19 acting on flange 13 compresses spring 29 so that sleeve 12 is drawn free of end 14 of barrel 1, the user may swing head 9 aside and load the syringe with a 1 cc. cartridge, screwing home threaded needle hub 38 in threaded end 39 of barrel 1, thus securing the cartridge firmly in the barrel. After engaging threaded bore 20 with the ampule plunger, the user shifts slide 26 to expose the 1 cc. indicium 32 so that the narrow portion 24 of rod 18 passes through the restricted part of the opening 28 of slide 26. The user may then remove the needle sleeve, insert the needle in the patient and aspirate a small amount of tissue fluid to determine whether or not a blood vessel has been entered. During aspiration and general handling of the syringe, shoulder 25 on rod IS prevents inadvertent withdrawal of the plunger from the 1 cc. ampule, the shoulder being so located that it will engage slide 25
before the plunger is pulled free. On completion of the injection, the entrance of taper 24' and enlargement 23' of rod 18 into the aperture of slide 26 forces the latter into the position exposing the 2 cc. indicium. This prepares the syringe for unloading—the reverse of the loading operation described above.
If the user wishes to use a 2 cc. ampule, he proceeds as above described through the step of loading and closing the syringe, but thereafter leaves the 2 cc. indicium on the slide exposed. In face he cannot shift the slide since the large part (23) of rod 18 passes through the enlarged opening 27 of slide 26. With a 2 cc. cartridge filling the entire barrel of the syringe there is no risk of inadvertently pulling the ampule plunger out of the ampule.
Figs. 5-7 illustrate a modified form of syringe operating on the same principle as that shown in Figs. 1-3 and 8, but having a different form of stop. In these figures, elements identical with those already described are designated by the same indices, while those that are analogous but somewhat different in form are designated by indices incerased by 100. Similarly analogous but different parts in Figures 8 and 9 are indicated by indices increased by 200 and 300 respectively.
The syringe illustrated in Fig. 5 has a barrel 101 having windows 107 and 108 in its sides. Head 109, pivoted on the barrel at 10 and 10' is the same in form as head 9 except that it lacks slots 17 and 17'. Spring 129 is longer than spring 29 and its proximal end bears directly on end wall 115 of head 109.
A slot 117 is provided in the side of barrel 101. A leaf spring 126 is attached to the barrel adjacent the slot by rivet 33. Spring 126 is biased outwardly so that normally it lies parallel to the barrel as shown in Fig. 7. A slide 34 is mounted on the barrel 101 by means of two studs 35 passing through slots 36 in the slide. A rectangular opening 40 is formed in the middle of slide 34 of sufficient width and length to permit spring 126 to lie outside of the bore of the barrel when slide 36 is moved to the left, as shown in Fig. 7, but sufficiently short to depress spring 126 into the barrel bore when slide 34 is moved to the right, as shown in Figs. 5 and 6. When spring 126 is forced into the barrel by slide 34, it acts as a fixed stop to limit movement of flange 19 when rod 113 is retracted. The position of the spring and slide longitudinally of the barrel is such that, when the syringe is used with a 1 cc. ampule and spring 126 is depressed, accidental withdrawal of the ampule plunger is prevented.
The method of use of this modification with 1 cc. and 2 cc. ampules is analogous to that of the previously described modification, due consideration being given to the difference in construction of the stop.
The previously described modifications are designed for use with cartridge-needle units which may be firmly secured in the syringe barrel by means of the threaded needle hub which mates with the threaded hole in the distal end of the barrel and which is crimped firmly on the ampule as described in above mentioned Dann Patent 2,671,450. By a simple modification of the stop, illustrated in Fig. 8, our syringe may be adapted for use with conventional separate needles and ampules. In this case provision must be made for avoiding retraction of the ampule as well as accidental withdrawal of the plunger.
In Fig.8 a conventional double pointed needle 204 with a threaded hub 241 is screwed into distal end of barrel 201 at 39. A conventional 1 cc. ampule 203 is then placed in the barrel and forced forward by finger pressure through the windows 207 until the needle pierces stopper 238. In order to introduce the ampule, thumb 70 screw 234, mounted in bracket 235 riveted to barrel 201 at 233, is unscrewed, permitting outwardly biased spring 226 to retract from the barrel through slot 217. The distal end of spring 226 is formed with two projections 242 and 243, the former of which engages flange 219 of the 75
plunger rod 218 and the latter the proximal end of the ampule 203 when rod 218 is retracted.
The method of use of this syringe is obvious from the previous descriptions.
Finally Fig. 9 illustrates a syringe designed to hold ampules of three sizes, e. g. 0.5 cc, 1 cc. and 2 cc. Barrel 1 has the same form as shown in Figs. 1. and 2; in Fig. 9 it is shown containing a 2 cc. ampule 6. Plunger rod 318, head 309 and stop 326 are of different form. Rod 318 has segments of three different diameters, that at the distal end 323 being largest and that at the proximal end
324 being smallest; the middle portion 324' has an intermediate diameter. Shoulders 325 and 325' define the meeting of the segments. Rod 318 passes through stop 326 mounted in slots 317 and 317' in head 309; the stop is pressed against the proximal edges of the slots by spring 29, and is retained by pin 335 passing through slot 336. The opening in stop 326 is of a modified clover-leaf shape, having three lobes of different diameters; the largest 327 permits passage of rod segment 323, the smallest 328 permits passage only of rod segment 324, and the intermediate lobe 328' permits the intermediate segment 324' but not the largest segment 323 to pass. It will be noted that slot 317 is wider than 317' so that stop 326 may be both slid and swung on pin 335, thus bringing any desired lobe of the opening into alinement with rod 318. The longitudinal positions of shoulders 325' and
325 correspond to the lengths of 0.5 cc. and 1 cc. ampules respectively.
The method of use of this syringe should be clear from the description of the use of the syringe of Figs. 1-4.
In the specification and claims the term "distal" indicates a direction towards the needle end of the syringe, and "proximal" the opposite direction.
1. An adjustable injection syringe adapted to be used with ampules of different lengths, each ampule being provided with a plunger having means for positive attachment to the plunger rod of the syringe, said syringe comprising: a barrel, an opening at the distal end of the barrel, means to retain an ampule in the barrel, a head movably mounted at the proximal end of the barrel to permit loading and closing the barrel, a plunger rod slidably mounted in the barrel head having means at its distal end for positive attachment to the ampule plunger, and stop means adapted optionally to limit the retraction of the plunger at an intermediate point in its over-all travel when an ampule shorter than the length of the syringe barrel is used, whereby inadvertent withdrawal of the plunger from the ampule is prevented, said stop means having an adjusting portion outside the syringe and having a portion engageable with the plunger rod at a point within the syringe.
2. An adjustable injection syringe as defined in claim 1 in which the plunger rod is formed with a larger diameter at its distal end, a smaller diameter at its proximal end and a shoulder between segments of different diameter, and in which the stop is a plate mounted transversely in the head and having an opening through which the plunger rod passes, the opening having one portion of restricted diameter permitting the passage of only the smaller segment of the plunger rod and one portion of larger diameter permitting passage of a larger segment of the plunger rod, the stop plate being movable in the head so that either portion of said opening may be brought into alinement with the plunger rod.
3. An adjustable injection syringe as defined in claim! in which the plunger rod is formed with a flange at its distal end and the stop is a, member mounted on the outside of the barrel intermediate its ends and movable at least in part through an adjacent slot in the barrel into the path of the plunger rod flange when it is retracted.
4. An adjustable injection syringe as defined in claim 3, in which the stop is a ieaf spring riveted to the out