Multiple dose paste dispenser

Abstract

A multiple dose paste dispenser in which the amount of the paste formulation which is dispensed is controlled by an adjustable stop means in the trigger housing of the dispenser.

Parent Case Text

RELATION TO OTHER APPLICATIONS

This application is a continuation-in-part of our earlier application, Ser. No. 279,599, filed Aug. 10, 1972 now abandoned.

Description

This invention relates to a multiple dose paste dispenser in which the paste formulation is dispensed in controlled amounts by means of a stop pin which is inserted in one of several holes in the trigger housing of the dispenser.

Dispensing guns that employ disposable cartridges are well known in the art, and usually, they comprise of a gun which supports the cartridge and which is provided with a lever actuated plunger that is adapted to engage and to move the cartridge piston toward the discharge end of the dispenser cartridge. In this way, the axial movement of the piston exerts pressure on the paste formulation contained in the dispenser cartridge and displaces the paste through the discharge spout. When it is desired to use a device of this type in order to dispense veterinary formulations it is necessary to be able to dispense variable doses of the formulation depending on the medicament, the type of animal, the size of the animal and the condition of the animal.

Accordingly, an object of this invention is to provide a paste dispenser gun which can accurately dispense variable controlled amounts of a paste formulation.

It is another object of this invention to provide a paste dispenser gun which may be economically produced and which is durable and readily adaptable to field conditions.

It is still another object of this invention to provide a paste dispensing device in which the cartridge is readily insertable and removable.

These and other objects and advantages of this invention will be more readily understood from the following description, taken in connection with the accompanying drawings in which:

FIG. 1 is a side elevation view, partly in cross section, of a once preferred form of this invention;

FIG. 2 is a side elevation view of the trigger housing in a first operating position;

FIG. 3 is a side elevation view of the trigger housing in a second operating position;

FIG. 4 is a side elevation view of the trigger housing in a third operating position;

FIG. 5 is a side elevation of a second preferred form of this invention;

FIG. 6 is a side elevation view in cross section of the trigger housing in the second embodiment; and

FIGS. 7, 8 and 9 are side elevation views in cross section of the trigger housing in three different operating positions.

Referring now more particularly to the drawings, the dispensing device 1 preferably includes a metal head frame 2 with a fixed handle 3, and with an end housing 4 secured thereto. The head frame 2 and end housing 4 have aligned openings (not shown) for the reception of a rotatable and axially movable piston rod 5 which has a piston 6 at its front end, a rear bend end 7 and, in the first embodiment, ratchet teeth 8 throughout its length. A movable trigger 9 is pivotally mounted in the frame 2 by a pivot pin 10.

In the first embodiment, a ratchet 11 is urged by a spring 12 into engagement with the ratchet teeth 8 when the piston rod 5 is positioned for that purpose. An abutment 13 for the spring 12 is provided in the trigger 9 and a retaining ratchet 14 urged by a spring 15 and carried on a pivot pin 16 in the frame 2 prevents rearward movement of the piston rod 5. A stop pin 17 in the frame 2 serves as an abutment for the spring 15 and as a stop for limiting forward movement of the trigger 9 which is so urged by spring 18. A stop pin 19 is attached to pivot pin 10 by means of a chain 20. This pin may be inserted into holes 21 or 22 in order to govern the distance that the piston is advanced and the amount of paste formulation which is expelled from the cartridge 23a which is secured to the dispenser gun 1 by nut 23 which is threaded and is screwed into end housing 4 in order to hold the cartridge securely in place.

As previously indicated, the dosage or amount of paste formulation which is dispensed is determined by whether stop pin 19 is inserted in hole 21, hole 22 or hole 23. The placement of the stop pin 19 determines the amount that the trigger 9 may be depressed, the distance that the piston rod 5 is advanced and the amount of paste formulation that is displaced and discharged by the piston 6.

When the stop pin 19 is in the position shown in FIG. 2 a given amount of paste formulation is dispensed. This amount depends on the diameter of the cartridge. When the stop pin 19 is in the position shown in FIG. 3, the amount of paste which is dispensed, is twice the amount which is dispensed when the stop pin 19 is in the position shown in FIG. 2 and when the stop pin 19 is in the position shown in FIG. 4 in hole 24 the amount of paste which is dispensed is three times that amount.

In the second embodiment, provision is made for a more flexible control of the dose dispensed. First, a different means for advancing the piston rod 5 is used. The ratchet 11 and the ratchet teeth 8 are replaced by a different mechanism. Within the frame 2 the piston rod 5 passes through holes in two successive pieces of metal forming together a gripping ring 25. This ring 25 presses against a spring 26 positioned around rod 5 between said ring 25 and the end housing 4. Outside of the head frame 4 is affixed a spring loaded lock 27 around piston rod 5. Under pressure of spring 28 lock 27 is pushed out at an angle and locks said rod 5 in place. Trigger 9 ends above pivot pin 10 in a hammer 29 which presses on ring 25 when the trigger is pulled. The motion of hammer 29 causes ring 25 to grip piston rod 5 and advance it. The motion of the rod 5 into the head frame 2 is permitted because in this direction it causes spring loaded lock 27 to press against spring 28. When pressure is released on hammer 29, the spring loaded lock 27 immediately seizes and holds rod 5 in the new position while gripping ring 25 returns to its initial position under pressure of spring 26.

In this second embodiment, also the stop pin 17 in replaced by an adjustable stop comprising a worm screw 30 terminating in an adjustment nut 31. Threaded on the worm screw 30 is a stop nut 32, shaped such that it cannot rotate when worm screw 30 is rotated. Stop nut 32 is therefore caused to advance up or down the handle 3 of the dispensing device 1. As can be seen from FIGS. 7, 8 and 9, the further down the handle stop nut 32 is positioned, the further trigger 9 can be pulled and consequently the further piston rod 5 is advanced. The dose dispensed is thus a direct function of positioning of stop nut 32. Desirably, indicia are put on head frame 3, with an indicator attached to stop nut 32 or as shown in FIG. 5, a slot 33 through which the exact position of nut 32 can be seen. The indicia calibrate the relative relationships of the doses administered at any settling of nut 32. Thus if the motion of rod 5 in FIG. 7 is one unit, in FIG. 8 it is six times that and in FIG. 9 as eight times the first unit.

Other variations will be obvious to those skilled in the art.

Claims

We claim:

1. A multiple dose paste dispensing gun comprising a frame having a handle affixed thereto, a piston rod having a piston on the front end thereof, means in said frame for guiding said piston rod for longitudinal movement thereon, a clamp on said frame for securing cartridges to extend therefrom in longitudinal alignment with said piston rod, a trigger, pivot means pivoting said trigger in said frame to be squeezed into said handle, rachet means above said pivot means and interconnected between said trigger and said piston rod to advance the rod and piston into a cartridge as said trigger is squeezed into said handle, said handle being formed with a plurality of openings below said pivot means at locations successively encountered by an edge of said trigger as said trigger enters into said handle during squeezing thereof and a stop pin removeably fitted into one of said openings to engage said trigger edge upon a given squeezing movement of said trigger whereby the distance the trigger may be moved from a fully extended condition is easily and accurately controlled to provide accurate dispensing of various paste dosages from said cartridge.

2. A device as in claim 1 wherein the stop pin is secured to the gun by means of a chain which is connected to the trigger.