Ampoule Applicator With One-way Clutch

Abstract

An ampoule applicator comprising a hollow, cylindrical body having a chamber at one end for mounting a medicament-containing hypodermic ampoule having a depressible portion for injecting a volume of medicament into a patient. The applicator also includes a spring-biased force-applying member for actuating the ampoule. The force-applying member may be retracted against the bias of the spring by a cocking lever which rotates a pulley at one end of the applicator. A flexible cable is fixed at one end to the force-applying member and is fixed at its other end to the pulley so that, as the pulley is rotated, the cable is wrapped about the pulley and the force-applying member is retracted. A one-way check mechanism is provided between the force-applying member and the applicator body to permit retraction of the force-applying member but to prevent movement toward the ampoule during retraction. The one-way check mechanism includes a slot in the applicator body having tapered sidewalls which converge toward the ampoule-mounting end of the applicator and a ball which is positioned between the force-applying member and the body. The ball is spring-biased into light frictional contact with the force-applying member and the converging sidewalls of the slot, and is operable to roll along the slot toward the ampoule-mounting end of the applicator by forward movement of the force-applying member and into tight frictional contact with the force-applying member to prevent movement of that member toward the ampoule. The force-applying member is released by inserting a pin in the slot to move the ball away from the ampoule-mounting end of the applicator.

Description

BACKGROUND OF THE INVENTION

This invention relates to reusable applicators for disposable hypodermic ampoules which are designed to give injections into or below the skin of human beings and animals. These applicators basically comprise an ampoule-receiving chamber at one end thereof and a spring-biased force-applying manner which is retracted or cocked against the force of the spring and locked in that position by a locking mechanism. When the locking mechanism is released, the force-applying member engages a depressible portion of the ampoule to cause medicament to be expressed from the ampoule and into the patient. The ampoule may be a needleless or hypojet injector which performs a hypodermic injection without employing a skin-penetrating needle to effect such injections. A more common ampoule is the contained needle-type having a cylindrical, medicament-containing chamber and a plunger closing one end thereof. A hollow needle is fixed to the plunger and is initially contained within such chamber and the other end of the ampoule is sealed by a diaphragm which is adapted to be punctured by the needle when force is applied to the plunger. With the diaphragm in contact with the patient's skin, the diaphragm may be punctured by the needle and the medicament may be injected into the patient as a function of the degree of depression of the plunger. Another form of ampoule is the collapsible type shown in U. S. Pat. Nos. 3,094,987 and 3,094,988 to Dunmire.

As was indicated previously, reusable ampoule applicators include a spring which biases the force-applying member toward the ampoule plunger and include a locking device which holds the plunger in a cocked or retracted position. The usual manner of moving the force-applying means to its cocked position is by means of a toggle mechanism or by means of an extension of the force-applying means which projects axially from the applicator. Examples of the toggle mechanism may be found in U. S. Pat. Nos. 3,094,121, 3,217,712, and 3,236,237. According to these patents, the applicator comprises an elongated, hollow body that houses a spring-biased force-applying member. An external arm or lever and a trigger mechanism are provided to retract the spring-biased force-applying member within the housing into a cocked position against the force of an actuating spring and to release or "fire" the force-applying member so that it is forcibly driven by the spring toward the ampoule for actuating it to perform an injection. The external arm or lever is connected to the force-applying member by a toggle linkage which retracts the force-applying member as the lever is swung away from the body of the applicator. The force-applying member includes two flanged members which are connected by a lost motion mechanism. The spring is positioned between end flanges of these members, and this entire assembly is drawn upwardly by the toggle linkage until a locking detent engages a portion of the sidewall of the hollow body. When the locking detent is engaged, the lever is then forced toward the applicator body to foreshorten the lost motion linkage and thereby compress the spring. By releasing the detent, the force-applying mechanism is driven toward the ampoule by the compression force in the released spring.

Although the toggle linkage-type applicator satisfactorily performs its intended function, there are certain disadvantages to such an arrangement. Firstly, the toggle linkage and the lost motion mechanism require a longer housing than is normally required merely to accommodate the effective stroke of the force-applying mechanism. This results in an unwieldy and somewhat bulky applicator. Furthermore, toggle linkage arrangements are subject to wear at a number of pivot points. Secondly, a major disadvantage of such an arrangement is the fact that if the handle is released prior to releasing the locking detent, the handle will spring back against the bias of the spring and may injure the user.

As was previously indicated, the force-applying member of an ampoule applicator may be retracted to a locked position by axially withdrawing a projecting end portion of the force-applying member. Such an arrangement is shown in U. S. Pat. Nos. 2,704,072 and 2,322,245 (FIGS. 12 and 13). Since these devices require a straight pull on the spring without any mechanical advantage, it is difficult to compress relatively strong springs. Furthermore, when the force-applying member is released (either accidentally while the force-applying member is being retracted, or deliberately by triggering the device), there exists the danger of pinching one's hand between the end of the applicator and the force-applying member.

SUMMARY OF THE INVENTION

According to this invention, an ampoule applicator is provided which alleviates the foregoing prior art problems by providing an improved cocking mechanism and an improved locking device which serves as a one-way check means or full stroke compelling mechanism for the force-transmitting member. It should be appreciated, however, that this invention may be employed in devices other than ampoule applicators. For example, this invention may be employed as a full stroke compelling mechanism for a hand-operated crimping tool for electrical terminals and connectors to ensure a proper crimp prior to release of the jaws. Furthermore, the invention may be employed in lever-operated air guns to prevent the lever from springing back on the user's hands prior to full cocking of the gun.

According to this invention, an ampoule applicator includes an elongated, cylindrical hollow body having one end adapted to removably receive an ampoule. The ampoule may be of the type which is adapted to inject a medicament into a patient by applying force to one end of the ampoule. The applicator also includes a force-transmitting member or piston having a rod portion directed toward the ampoule, a head portion which is biased toward the ampoule by a relatively strong spring, and a lockable and releasable cocking mechanism for retracting the piston against the bias of the spring. As presently preferred, the cocking mechanism comprises a flexible cable having one end fixed to the head portion of the piston and its other end fixed to the periphery of a pulley which is mounted at the other end of the hollow, cylindrical body. The force-applying member may be retracted against the bias of the spring by a lever or handle which, in this instance, rotates the pulley to thereby wind the flexible cable about the periphery of the pulley.

During retraction of the force-transmitting member, the tendency of the force-transmitting member to be driven toward the ampoule by the spring is resisted by a one-way check means or full stroke compelling mechanism. The one-way check means includes a rollable member, such as a sphere, which is positioned between the piston rod and the cylindrical housing. A wedge means is provided which causes the rollable member to be forced into firm frictional engagement with the piston rod and thereby restrain any tendency of the rod to move toward the ampoule. According to one aspect of this invention, the wedge means comprises a tapered slot in the cylindrical housing having sidewalls which coverge toward an imaginary apex which is directed toward the ampoule so that as the rollable member is rolled along the slot by movement of the rod toward the ampoule, it is progressively forced radially inwardly toward the rod by movement of the rod toward the ampoule, with a wedging effect that opposes such movement of the rod.

With the force-applying member in a retracted position and with an ampoule properly installed in the applicator, the force-applying member may be triggered or released by moving the rollable member out of its firm frictional engagement with the rod. According to the specific embodiment illustrated herein, this is accomplished by a pin mounted on the lever or handle which may be extended into the tapered slot to drive the rotatable member away from the imaginary apex of the tapered slot. To prevent repeated firing of the applicator (which would tend to cause fatigue to certain elements thereof) when an ampoule is not positioned in the applicator, a blocking device is provided which prevents entry of the pin into the slot unless the blocking means is contacted by an ampoule.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross sectional view of the applicator according to this invention showing the applicator in a "fired" condition.

FIG. 2 is an elevational view of the applicator, with portions broken away for clarity, showing the applicator in a cocked condition, with the lever not yet returned to a positioned adjacent the body of the applicator.

FIG. 3 is a fragmentary view of the applicator illustrating the tapered slot.

FIG. 4 is an end view of the applicator with portions broken away for clarity.

FIG. 5 is a partially schematic view, illustrating the travel of the rollable member along the tapered slot.

DETAILED DESCRIPTION OF THE INVENTION

There is disclosed in the drawing an ampoule applicator 10 which, in combination with a hypodermic ampoule 11, is adapted to inject a medicament into a patient. The particular hypodermic ampoule 11 illustrated herein is more fully described in the copending application of Hurschman et al., Ser. No. 114,493, filed Feb. 11, 1971, now U.S. Pat. No. 3,735,761, and assigned to the same assignee as the present application. The ampoule 11 comprises a cylinder 12 which is preferably made from glass tubing.

One end of the cylinder 12 is closed by a diaphragm 14 which is pressed against it by a plastic clip 15. This closure arrangement is more fully described in the copending application of Hurschman et al. The other end of the cylinder 12 is closed by a plunger 20 formed to have a sliding interference fit with the inner sidewall of the cylinder 12. The plunger 20, the diaphragm 14, and the cylinder 12, together, define a chamber 21 which is substantially filled with a liquid medicament.

Entirely enclosed within the chamber 21 is a hypodermic needle 22. The hypodermic needle 22 has a circular base (not shown) at the butt end of the needle that is mounted on the plunger 20 so that the needle is in substantial axial alignment with the cylinder 12 so that the pointed end of the needle is in position to be forced through the diaphragm 14.

The ampoule applicator 10 includes a cylindrical housing 30 having an axial bore 31 and a counterbore 32 therein. In order to mount the hypodermic ampoule 11 in the applicator 10, a mounting sleeve 33 is provided. The mounting sleeve 33 is threaded into one end of the applicator 10 and has an annular, axially extending, inwardly offset shoulder 35 at one end thereof. The ampoule 11 is installed in the mounting sleeve 33 by inserting it through an opening 36 in the sleeve 33 and is held within the sleeve by a bayonet-type connection between the ampoule 11 and the sleeve. This connection is more fully set forth in the copending application of Hurschman, Ser. No. 114,423, filed Feb. 11, 1971, now U.S. Pat. No. 3,729,003. With the ampoule 11 properly installed in this manner, the opposite end of the ampoule cylinder 12 projects a predetermined distance beyond the shoulder 35.

The ampoule applicator 10 also includes a force-applying mechanism for driving the ampoule plunger 20 from the position illustrated in FIG. 2 to the position illustrated in FIG. 1. The force-applying mechanism comprises a force-applying member or piston 45 having a head portion 46 which is slidably mounted within the counterbore 32 and a piston rod 47 which axially projects toward the ampoule plunger 20. The piston 45 is biased downwardly as viewed in the drawing by a relatively strong compression spring 48.

The piston 45 may be retracted from the "fired" position illustrated in FIG. 1 to the cocked position illustrated in FIG. 2 by grasping a handle 49 and swinging the handle 49 away from the body 30 to the position illustrated in FIG. 2. The handle 49 is pivotally connected at its upper end to a pin 50 which extends transversely with respect to the bore 31. The upper end of the handle 49 is bifurcated to provide a pair of spaced flanges 51 and 52. Rotatably mounted on the pin 50 is a pulley 53 which has a circumferential groove 54 formed in its periphery. The groove 54 has a flattened portion 55 and a cross pin 56 extends across the flattened portion. As may be seen most clearly in FIG. 4, the pin 56 projects outwardly beyond the pulley faces. One end of a flexible cable 57 is fixed to the pin 56, and the other end of the cable is fixed to the piston head 46 by a pin 58 extending across a shallow groove 59 cut into the piston head.

The piston 45 is raised to a retracted position by swinging the handle 49 outwardly relative to the body 30. As the handle 49 is swung outwardly, abutment portions 60 and 61 on the flanges 51 and 52 bear against the extensions of the pin 56 to rotate the pulley 53 in a counterclockwise direction, as viewed in FIGS. 1 and 2, so that the flexible cable 57 is progressively wrapped about the pulley groove 54. As the cable 57 is wrapped about the pulley, the piston 45 is retracted against the bias of the spring 48.

There is provided a one-way check means or full stroke compelling mechanism which permits movement of the piston toward its retracted position but which prevents movement of the piston toward its fired or extended position until the check means is released. In the illustrated embodiment, the check means includes a rollable member or ball 62. The ball 62 is assembled in the bore 32 by inserting it through a semicircular opening 63 in the body 30. The diameter of the opening 63 is slightly greater than the diameter of the ball 62 to permit this insertion step. The semicircular opening 63 blends into straight coverging walls 64 and 65, which form a tapered or V-shaped slot. As may be seen in FIG. 5, as the ball 62 travels from the opening 63 along the inside edges of the converging slot walls 64 and 65, the center of the ball traces an imaginary line L, which approximates a hyperbolic curve and which curves toward the piston rod 47. To ensure frictional contact at all times between the ball 62 and the rod 47, and between the ball 62 and the inside edges of the surfaces 64 and 65, a relatively light compression spring 70 is provided which tends lightly to urge the ball toward an imaginary apex.alpha. of the tapered slot.

Thus, as the piston rod 47 is retracted in the previously described manner, the piston rod 47 moves the ball 62 toward the opening 63 just enough so that relatively light pressure is exerted on the piston rod 47 by the ball 62. If, during retraction of the rod 47, the handle 49 is released, the rod 47 is urged toward the ampoule plunger 20 by the spring 48. Any noticeable return movement of the rod 70 in this direction, however, is resisted by the ball, since the rod 47 will tend to rotate the ball 62 toward the apex of the V-shaped notch, thus driving the ball into firmer frictional contact with the rod 47 as the ball 62 rides inwardly on the inside edges of the notch faces 64 and 65. It will be readily seen that this action rapidly builds up the pressure of the ball against the rod 47 and edges of the walls 64 and 65, and builds up the friction therebetween at a corresponding rate. As a result, only a minute movement of the piston 45 causes a wedging of the ball between the piston rod 47 and walls 64 and 65 that stops further rolling of the ball in that direction while increasing the friction between the ball and the piston rod so that return movement of the piston is almost instantly arrested.

In order to ensure that the ball 62 will effectively restrain the rod 47 against forward movement toward the ampoule during retraction, the ball diameter, the angle included by the converging sidewalls 64 and 65, and the distance between the rod 47 and the body 30 are selected so that a preselected effective wedging angle obtains. It is known that a ball will restrain movement in one direction between relatively movable members if one of the members is provided with a wedge which slopes toward the other member at a preselected angle which exceeds the coefficient of sliding friction between the ball and the movable members. This principle is employed in overrunning clutches. For a steel ball in contact with steel members, the preselected angle should be between about 5.degree. and 12.degree., and preferably should be 71/2.degree.. If the angle is less than 5.degree., the frictional contact will be too great and it may be difficult to release the ball from frictional contact. If, on the other hand, the angle exceeds 12.degree., the wedging action will not be firm enough and slippage may occur.

According to the present invention, it has been found that a ball rolling in a slot having converging sidewalls produces a wedging effect which corresponds to the wedging effect which results from the use of an actual wedge and which, itself, has an effective wedging angle. It is, of course, far simpler to merely stamp or cut a slot in a member than it is to weld or otherwise affix a separate wedge to one of the members. As used in the specification and claims of this application, the term "effective wedging angle" is hereby defined as the slope of the locus of points traced by the center of a sphere rolling along a slot formed in a surface and having converging sidewalls, with the slope measured at the intersection of the locus and a plane defined by three points of contact by the sphere with the sidewalls of the slot and a member spaced from the slot (e.g., the rod 47). The effective wedging angle is between about 5.degree. and 12.degree., and is preferably 71/2.degree..

In FIG. 5, the line L represents the locus and the ball 62 is shown to be locked in a position producing an effective wedging angle of 71/2.degree., with the intersection of the curve L (the locus) and the aforementioned plane P being indicated by the reference numeral 95. It has been found that if the inside diameter of the housing 30 is 0.650 inch, if the diameter of the rod 47 is 0.300 inch, if the diameter of the ball 62 is 0.218 inch, and if the angle included by the sidewalls 64 and 65 is about 28.degree., an effective wedging angle will obtain.

A particular advantage of the slot and ball arrangement is that as the sidewalls 64 and 65 wear after repeated use, the ball will tend to operate in a position closer to the convergence of the walls 64 and 65 and, therefore, the effective wedging angle will be less than 71/2.degree.. Therefore, the wedging effect will increase during use of the device.

Although the spring 70 biases the ball 62 away from the opening 63, and ensures that the ball will not accidentally drop out of the opening 63, a further means is provided to ensure that the ball will remain in the applicator and to prevent tampering with the ball. To this end, there is provided a sleeve 71 which extends from the sleeve 33 to a location which ensures that the opening 63 will be covered. For a purpose which will hereinafter become apparent, a portion of the slot is left uncovered by an aperture 72 in the sleeve 71.

The fully retracted position of the piston 45 is illustrated in FIG. 2 and is established when the handle 49 engages a stop portion 73 of the body 30. After the piston 45 is retracted in this manner, the handle 49 may be returned to the position illustrated in FIG. 1, and the piston 45 will be held in its retracted position by the ball wedging action of the one-way check means. An ampoule 11 may then be installed in the applicator in the previously described manner.

For firing the piston 45, means are provided to release the one-way check means and render it inoperative during the piston stroke. To this end, there is provided a pin 74 in the handle 49. The pin 74 is slidably mounted in an aperture 75 and has a head portion which bears against a sloped camming surface 76 of a trigger piston 77. The trigger button 77 is slidable within a slot 78 in the handle 49 and is biased to the position illustrated in FIG. 1 by a spring 79. By pushing the button 77 downwardly along the slot 78 and against the bias of the spring 79, the cam surface 76 forces the pin 74 axially through the opening 75 toward the body 30 so that the pin 74 enters the body 30 through parallel extensions 80 of the slot walls 64 and 65. As the pin 74 enters between the extensions 80, a rounded end portion 81 of the pin engages an edge 82 of a washer 83 which is loosely mounted within the bore 32 and surrounds the piston rod 47. The washer 83 is thereby driven upwardly, as viewed in FIG. 1, so as to drive the ball 62 upwardly and away from the imaginary apex .alpha. of the tapered slot and out of firm frictional engagement with the rod 47. When the ball 62 has been moved in this manner, the spring 48 drives the piston 45 downwardly to drive the plunger 20 to the position illustrated in FIG. 1 and thereby actuate the ampoule 11 to perform an injection.

Of course, it should be appreciated that the pin 74 could be located so that it would directly engage the ball 62 and the washer 83 could be eliminated. However, the washer 83 performs a second function of preventing release of the ball 62 by the pin 74 unless an ampoule is properly installed within the applicator. As may be seen in FIG. 1, insertion of an ampoule into the applicator lifts the washer 83 away from the shoulder 35 as required to permit the pin to engage the lower edge 82 of the washer. If the washer 83 is not lifted by the ampoule, it rests on the shoulder 35 in the position shown in dotted outline in FIG. 1 to effectively block entry of the pin 74 into the extension 80. So that the washer 83 will perform its blocking function when the applicator is held in any position, a light spring 90 is provided which urges the washer 83 toward the shoulder 35.

The invention is not restricted to the slavish imitation of each and every one of the details described above, which have been set forth merely by way of example with the intent of most clearly setting forth the teaching of the invention. Obviously, devices may be provided which change, eliminate, or add certain specific details without departing from the invention.

Claims

We claim:

1. An ampoule applicator comprising a body and means for mounting thereon a medicament-containing hypodermic ampoule adapted to inject a volume of medicament into a patient, said applicator also including force-applying means mounted on said body for forward movement toward said ampoule mounting means along a predetermined path from a fully retracted position, means biasing said force-applying means forwardly along said path, means for reversely moving said force-applying means to its fully retracted position against the bias of said biasing means, and one-way check means permitting reverse movement of said force-applying means toward its retracted position but preventing any substantial forward movement of said force-applying means toward said ampoule mounting means when said force-applying means is in its fully retracted position and when said force-applying means is in any position forward thereof, said one-way check means comprising a rollable member and wedge means normally urging said rollable member into firm frictional contact with said force-applying means to restrain forward movement thereof but permitting reverse movement thereof toward its retracted position, said check means being releasable to permit said forward movement, said wedge means comprising means defining a tapered slot in said body, said slot having sidewalls converging toward said ampoule mounting means.

2. An ampoule applicator according to claim 1, wherein said rollable member is spherical and normally positioned to roll along said tapered slot.

3. An ampoule applicator according to claim 2, including means biasing said rollable member toward the ampoule mounting means.

4. An ampoule applicator according to claim 1, including means to relieve firm frictional contact of said rollable member with said force-applying means for permitting said forward movement of said force-applying means.

5. An ampoule applicator according to claim 1, wherein the sidewalls of said tapered slot converge at an included angle to produce an effective wedging angle of between about 5.degree. and 12.degree..

6. An ampoule applicator according to claim 1, wherein the sidewalls of said tapered slot converge at an included angle of about 28.degree..

7. An ampoule applicator according to claim 1, wherein said means for moving said force-applying means to its retracted position against the bias of said spring means includes pulley means mounted on said body and flexible cable means having one end fixed to said force-applying means, and an opposite end fixed to said pulley means, and means to rotate said pulley means so that portions of said cable means are wrapped about said pulley means for pulling said force-applying means toward its retracted position.

8. An ampoule applicator according to claim 7, wherein said pulley means is rotatably mounted on said body, and wherein said means to rotate said pulley means comprises a lever pivotally mounted on said body for swinging movement from a first position to a second position relative to said body, said pulley and lever having abutment means engaged by swinging said lever toward its second position for rotating said pulley and disengaged by reverse swinging of said handle toward its first position while forward movement of said force-applying means is restrained by said one-way check means.

9. An ampoule applicator comprising a body and means for mounting thereon a medicament-containing hypodermic ampoule having medicament-injecting means adapted to inject a volume of medicament into a patient, said applicator also including force-applying means mounted on said body for movement toward said ampoule from a retracted position relative to said body for actuating said ampoule, means biasing said force-applying means toward said ampoule, means for moving said force-applying means to its retracted position against the bias of said biasing means, said means for moving said force-applying means including pulley means mounted on said body, flexible cable means having one end fixed to said force-applying means and its opposite end fixed to said pulley means, means to rotate said pulley means so that portions of said cable means are wrapped about said pulley means to pull said force-applying means toward its retracted position and one-way check means, said one-way check means comprising a rollable member and wedge means normally urging said rollable member into firm frictional contact with said force-applying means to restrain forward movement thereof but permitting reverse movement thereof toward its retracted position, said check means being releasable to permit said forward movement, said wedge means comprising means defining a tapered slot in said body, said slot having sidewalls converging toward said ampoule mounting means.

10. An ampoule applicator according to claim 9, wherein said rollable member is spherical and normally positioned to roll along said tapered slot.

11. An ampoule applicator according to claim 10, including means biasing said rollable member toward the ampoule mounting means.

12. An ampoule applicator according to claim 9, including means to relieve firm frictional contact of said rollable member with said force-applying means for permitting said forward movement of said force-applying means.

13. An ampoule applicator according to claim 10, wherein the sidewalls of said tapered slot converge at an included angle to produce an effective wedging angle of between about 5.degree. and 12.degree..

14. An ampoule applicator according to claim 10, wherein the sidewalls of said tapered slot converge at an included angle of about 28.degree..

15. An ampoule applicator according to claim 9, wherein said pulley means is rotatably mounted on said body, and wherein said means to rotate said pulley means comprises a lever pivotally mounted on said body for swinging movement from a first position to a second position relative to said body, said pulley and lever having abutment means engaged by swinging said lever toward its second position for rotating said pulley and disengaged by reverse swinging of said handle toward its first position while forward movement of said force-applying means is restrained by said one-way check means.

16. An ampoule applicator according to claim 12, wherein said pulley means is rotatably mounted on one end of said body, wherein said means to rotate said pulley means comprises a lever pivotally mounted on said body for swinging movement from a first position to a second position relative to said body, said pulley and lever having abutment means engaged by swinging said lever toward its second position for rotating said pulley and disengaged by revese swinging of said handle toward its first position while forward movement of said force-applying means is restrained by said one-way check means, and wherein said means to remove aid rollable member from its frictional contact with said force-applying means comprises pin means on said lever which is operable to move said rollable member out of firm frictional contact with said force-applying means when said lever is in its first position.

17. An ampoule applicator according to claim 16, including means operable when an ampoule is not installed in said applicator to block said pin means and prevent movement of said rollable member out of firm frictional contact with said force-applying member.

18. An ampoule applicator comprising a body and means for mounting thereon a medicament-containing hypodermic ampoule having medicament injecting means adapted to inject a volume of medicament into a patient, said applicator also including force-applying means mounted on said body for movement toward said ampoule from a retracted position relative to said body for actuating said ampoule, means biasing said force-applying means toward said ampoule, means for moving said force-applying means to its retracted position against the bias of said biasing means, said means for moving said force-applying means including pulley means mounted on said body, flexible cable means having one end fixed to said force-applying means and its opposite end fixed to said pulley means, means to rotate said pulley means so that portions of said cable means are wrapped about said pulley means to pull said force-applying means toward its retracted position, one-way check means, said one-way check means comprising a rollable member and wedge means normally urging said rollable member into firm frictional contact with said force-applying means to restrain forward movement thereof by said biasing means but permitting reverse movement thereof toward its retracted position, said check means being releasable to permit said forward movement, means to relieve first frictional contact of said rollable member with said force-applying means for permitting said forward movement of said force-applying means, said pulley means being rotatably mounted on one end of said body, said means to rotate said pulley means comprising a lever pivotally mounted on said body for swinging movement from a first position to a second position relative to said body, said pulley and lever having abutment means engaged by swinging said lever toward its second position for rotating said pulley and disengaged by reverse swinging of said handle toward its first position while forward movement of said force-applying means is restrained by said one-way check means, said means to remove said rollable member from its frictional contact with said force-applying means comprising pin means on said lever which is operable to move said rollable member out of firm frictional contact with said force-applying means when said lever is in its first position.

19. An ampoule applicator according to claim 18, including means operable when an ampoule is not installed in said applicator to block said pin means and prevent movement of said rollable member out of firm frictional contact with said force-applying member.