Implant Gun

Abstract

Subcutaneous implant gun for dispensing pellets comprises case with hollow needle attached thereto. Plunger in alignment with hollow needle reciprocates to expell pellets through needle as pellets are positioned in path of plunger travel. Reciprocable bushing in alignment with hollow needle supportingly surrounds plunger. Trigger pivoted to case is connected to reciprocable bushing and plunger, and linkage system between trigger and bushing and plunger causes bushing and plunger to move in direction of hollow needle when trigger is depressed. Bushing and plunger move away from hollow needle when trigger is released.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an implant gun, and more particularly to a subcutaneous implant gun for dispensing pellets through a hollow needle from the magazine of a cartridge holding a plurality of pellets.

In the past, numerous implant gun constructions have been proposed for dispensing solid pellet material. Many of these heretofore proposed constructions are characterized by their complex and inefficient mode of operation as well as the unusually large number of parts required to construct them. In many instances, the moving parts of these implant guns tend to wear out very rapidly thereby rendering the constructions useless. Jamming is also a problem.

Accordingly, it is an object of the present invention to provide a simple and easy-to-use implant gun which functions in a highly dependable and trouble-free manner to dispense implant pellets from a cartridge holding a plurality of pellets.

SUMMARY OF THE INVENTION

In accordance with the present invention, a subcutaneous implant gun for dispensing pellets comprises a case with a hollow needle attached to the front portion of the case. A reciprocable plunger is in alignment with the hollow needle for expelling pellets through the hollow needle as the pellets are positioned in the path of plunger travel. A reciprocable bushing also in alignment with the hollow needle supportingly surrounds the plunger. A trigger pivoted to the case is connected to reciprocate the bushing and the plunger. A linkage system connected between the trigger and the bushing and plunger causes the bushing and plunger to move in the direction of the hollow needle when the trigger is depressed. The plunger moves away from the hollow needle when the trigger is released.

The forward end of the bushing adjacent the hollow needle may be chamfered. Moreover, a cartridge holder can be positioned between the hollow needle and the bushing for accommodating a cartridge containing a plurality of implant pellets. Preferably, the case of the implant gun includes a pair of tracks that parallel the path of travel of the plunger. Pins connected to the plunger are positioned in the tracks for supporting the plunger as it reciprocates along its path of travel.

The linkage system may include a cam link pivotally connected to the case having a cam track thereon. A first connected link between the trigger and the cam link rotates the cam link about its pivotal connection when the trigger is manipulated. A second connector link between the cam link and the plunger reciprocates the plunger along its path of travel as the cam link rotates. A bell crank pivotally connected to the case has a cam follower at one end thereof that engages the cam track on the cam link for rotating the bell crank as the cam link rotates. The other end of the bell crank is connected to the bushing for reciprocating the bushing along its path of travel as the ball crank rotates.

BRIEF DESCRIPTION OF THE DRAWING

Novel features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawing wherein:

FIG. 1 is a top plan view of a subcutaneous implant gun according to the present invention;

FIG. 2 is a side elevational view of the implant gun illustrated in FIG. 1;

FIG. 3 is a front elevational view of the implant gun illustrated in FIGS. 1 and 2;

FIG. 4 is a top plan view of the subcutaneous implant gun shown in FIGS. 1-3 with the upper half of the gun case removed and portions broken away to show interior details;

FIG. 5 is a view similar to FIG. 4 illustrating one stage in the sequence of operation of the implant gun according to the present invention;

FIG. 6 is a view similar to FIGS. 4 and 5 illustrating still another stage in the sequence of operation of the implant gun according to the present invention; and

FIG. 7 is a sectional view taken along line 7--7 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a subcutaneous implant gun 10 comprises a case 12 including an upper half 14 and a lower half 16 releasably secured together by machine screws 18. The gun case halves are shaped to provide a cavity 20 for holding mechanisms that dispense implant pellets of solid material from the rotary magazine of a cartridge 22 containing a plurality of such pellets. The cartridge 22 is releasably secured to a cartridge holder 24 arranged to accommodate the cartridge. A hollow needle 26 is fixed to a collet 28 on the cartridge holder by a collet nut 30.

The structural relationship between the cartridge 22 and the cartridge holder 24 is such that the implant pellets held by the rotary magazine of the cartridge 22 are in alignment with the hollow needle 26 as the magazine is caused to rotate within the cartridge case. As explained in detail in copending application Ser. No. 633,886, filed Apr. 26, 1967, now U.S. Pat. No. 3,520,299, the cartridge 22 includes an integrally hinged activator element 32 that operates to advance the magazine immediately prior to the dispensing of an implant pellet. For the purpose of this application it is sufficient to state that when the activator element 32 of the cartridge 22 is flexed about its integral hinge or in other words urged upwardly as viewed in FIGS. 4-6, the magazine of the cartridge is caused to rotate a sufficient distance so as to position the next implant pellet to be dispensed at a location for dispensing. After that pellet is dispensed and just prior to the next dispensing operation the activator element 32 is again flexed about its integral hinge to thereby position the next pellet in the magazine at a location for dispensing.

As indicated above, the upper and lower halves of the gun case 12 provide a cavity 20 for housing the mechanisms that accomplish the pellet dispensing operation. A bridge plate 34 is secured to the lower half 16 of the gun case 12 by machine screws 36. The bridge plate is fixed relative to the gun case 12 and includes a pair of pivot mounting points, for purposes explained below. A cam link 38 is pivoted to the bridge plate 34 at one of the two pivot points on the plate by a pivot pin 40. The cam link 38 has a cam track 42 the function of which is explained below. One end of the cam link is pivotally connected to a yoke link 44 which in turn is pivotally connected to one end of a reciprocable push rod or plunger 46 by a swivel 48. The push rod or plunger 46 reciprocates along a path of travel in alignment with the hollow needle 26. As shown best in FIGS. 5 and 7, the swivel 48 includes a pair of stud rods 50 which extend outwardly therefrom and ride in tracks 52 formed in the upper and lower halves of the gun case 12. This arrangement assists in controlling the path of travel of the plunger 46 as well as supporting the plunger as it reciprocates. The plunger 46 has a pair of longitudinally oriented grooves or channels 53 that prevent jamming due to accumulated pellet dust inside the bushing 62. Without such grooves dust can easily accumulate between the bushing and the plunger and cause jamming.

A bell crank 54 is pivotally connected to the bridge plate 34 at the other of its pivot points by pivot pin 56. One end of the bell crank 54 carries a cam follower 58 which rides in the cam track 42 on the cam link 38. As explained more fully below, as the cam link 38 is caused to rotate about the cam link pivot pin 40, the cam follower 58 on the bell crank 54 rides in the cam track 42 of the link 38 to thereby cause the bell crank 54 to rotate about its pivot 56. The end of the bell crank 54 opposite the cam follower 58 is pivotally attached to a twist link 60 which in turn is secured to a reciprocable bushing 62. Movement of the bell crank 54 about its pivot pin 56 causes the bushing 62 to reciprocate along a path of travel in alignment with the hollow needle 26. As the bushing moves outwardly from the gun case 12 a forward chamfered end portion 64 engages the activator element 32 of the implant cartridge 22. As explained more fully below, continued outward movement of the bushing 62 flexes the activator element 32 about its integral hinge to advance the rotary magazine of the cartridge 22. As shown best in FIGS. 4-6, the bushing 62 supportingly surrounds the plunger 46 at the end of the plunger opposite its connection to the yoke link 44.

A trigger 68 pivoted to the gun case 12 by a pivot pin 70 is provided for reciprocating the plunger 46 and the bushing 62. The trigger 68 is pivotally connected to the cam link 38 by an arcuate shaped connector link 72, as shown best in FIGS. 4-6. As viewed in FIGS. 4-6, when the trigger 68 is depressed into the gun case 12, the cam link 38 is caused to rotate in a counterclockwise direction about its pivot pin 40. The rotating cam link rotates the bell crank 54 in the same direction. Together, the cam link and bell crank cause the plunger 46 and bushing 62 to move outwardly from the gun case 12 to accomplish the dispensing operation in the manner explained below.

A coil spring 74 positioned between a spring seat 75 on the trigger 68 and a spring seat 76 on case half 16 operates to return the trigger 68 to its starting position outwardly of the gun case 12. Fixed stops 78 and 80 are provided to limit the movement of the trigger and cam link, respectively. A lip 82 on the trigger 68 limits the outward movement of the trigger by engaging the case 12, as shown in FIGS. 4-6.

With a full cartridge 22 positioned within the cartridge holder 24, the sequence of operation of the subcutaneous implant gun 10 is as follows. First, the trigger 68 is depressed thereby causing it to rotate about its pivot pin 70 into the gun case 12. Such movement places the arcuate connector link 72 under tension and causes that link to rotate the cam link 38 in a counterclockwise direction, as viewed in FIGS. 4-6. The motion of the cam link 38 is transmitted to the bell crank 54 via the cam track 42 and the cam follower 58 on the bell crank. The first few degrees of rotation of the cam link 38 operate to urge the bell crank 54 to the full extent of its counterclockwise rotary motion. Continued rotation of the cam link does not cause the bell crank to rotate. The motion of the bell crank is transmitted to the bushing 62 by the twist link 60. This movement urges the bushing from the position shown in FIG. 4 to the position shown in FIG. 5. The forward chamfered portion 64 of the bushing 62 slides across the inclined surface of the activator element 32 of the cartridge 22 to flex the activator about its integral hinge and thereby rotate the magazine of the cartridge to position an implant pellet in the path of plunger travel which path is in alignment with the hollow needle 26.

The plunger 46 and the busing 62 move together as the trigger 68 is depressed inwardly into the gun case 12. However, the plunger does not emerge from the bushing until after the activator element 32 has been flexed out of the path of plunger travel. With the activator element out of the way of the plunger continued inward movement of the trigger 68 about its pivot pin 70 urges the plunger 46 through the pellet containing opening in the rotary magazine of the cartridge 22 and into the hollow needle 26. Ultimately, the plunger is positioned as shown in FIG. 6 and the implant pellet being dispensed is expelled through an out of the hollow needle 26. The trigger 68 is then released and the coil spring 74 returns the trigger to its starting position. Since the trigger is connected to the plunger 46 through the arcuate connector link 72, the cam link 38, and the yoke link 44 the plunger is returned to its starting position along with the trigger. When the trigger is released the clockwise rotation of the cam link 38, as viewed in FIGS. 4-6, ultimately causes the bell crank 54 to rotate in a similar direction. Such rotation of the bell crank is transmitted to the bushing 62 through the twist link 60 and the bushing returns to its starting position shown in FIG. 4. The implant gun 10 is then ready to dispense the next implant pellet in the magazine of the cartridge 22.

Claims

WHAT IS CLAIMED IS:

1. A subcutaneous implant gun for dispensing pellets comprising a case with a hollow needle attached thereto, a reciprocable plunger in alignment with the hollow needle for expelling pellets through the hollow needle as they are positioned in the path of plunger travel, a reciprocable bushing in alignment with the hollow needle supportingly surrounding the plunger, both the plunger and the bushing being reciprocable along a path in alignment with the hollow needle, a trigger pivoted to the case connected to reciprocate the bushing and the plunger, and a linkage system connected between the trigger and the bushing and plunger for causing the bushing and plunger to move in the direction of the hollow needle when the trigger is depressed and the plunger away from the hollow needle when the trigger is released.

2. A subcutaneous implant gun as in claim 1 wherein the forward end of the bushing adjacent the hollow needle is chamfered.

3. A subcutaneous implant gun as in claim 1 wherein the linkage system includes a cam link pivotally connected to the case having a cam track thereon, a first connector link between the trigger and the cam link for rotating the cam link about its pivotal connection when the trigger is moved, a second connector link between the cam link and the plunger for reciprocating the plunger along its path of travel as the cam link rotates, a bell crank pivotally connected to the case, one end of the bell crank having a cam follower that engages the cam track on the cam link for rotating the bell crank as the cam link rotates, and means connecting the other end of the bell crank to the bushing for reciprocating the bushing along its path of travel as the bell crank rotates.

4. A subcutaneous implant gun as in claim 3 wherein the trigger is spring biased away from the case whereby when the trigger is released it moves outwardly from the case and withdraws the plunger away from the hollow needle.

5. A subcutaneous implant gun as in claim 1 including a cartridge holder positioned between the hollow needle and the bushing arranged to accommodate a cartridge containing a plurality of implant pellets.

6. A subcutaneous implant gun as in claim 1 wherein the case includes a pair of tracks that parallel the path of travel of the plunger, and pins connected to the plunger and positioned in the tracks for supporting the plunger as it reciprocates along its path of travel.