GB2333128A

GB2333128A - Dispensing gun trigger arrangement

Info

Publication number: GB2333128A
Application number: GB9713402A
Authority: GB
Inventors: Desmond Charles Drummond; Andrew Robertson Drummond
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-06-26
Filing date: 1997-06-26
Publication date: 1999-07-14
Anticipated expiration: 2017-06-26
Also published as: GB2333128B; GB9713402D0

Abstract

A dispensing gun has a trigger 18 pivotably mounted within pivot holes 19h in a handle, or stock, 12 by means of a pivot pin 19 having a retaining collar (31, figures 3A and 3B). The trigger 18 has two side portions 18f, 18b which fit over and either side of the handle 12. The handle 12 is made from a single sheet of material and the trigger 18 from a double sheet of material, preferably of moulded or extruded plastics. The gun has a body 11 in which two parallel spaced elongate barrel members 14t,14b extend between the handle 12 and a muzzle 13. A piston rod 16, slidably mounted through a pair of spaced apertured support members 15l, 15r in the handle 12, is driven via a piston rod drive member 17 by a piston-drive-member cam 20 on the trigger 18.

Description

Sealant guns This invention relates to sealant guns, and concerns in particular the sort of gun-like device into which may be fitted, for being dispensed therefrom, a cartridge or tube of a viscous or pastey material such as a mastic, caulkant or sealant.

It is commonplace to provide thick, viscous, pastey materials (such as mastics, sealants and substances for caulking) in a tube with a nozzle (or means for fitting a nozzle) at one end and a base which is in the form of a piston or plunger slidably mounted within the tube.

By pushing the piston up the tube so the contents thereof are gradually pushed through the nozzle and out of the tube into contact with whatever surface they are required on, and if at the same time the nozzle is moved along the surface then the extruded contents form a line of material. In this manner a neat, tidy bead or fillet of material may be formed at the junction between two surfaces - between a wall and a workbench top, for example - to fill up and seal off the gap between the two.

Although this pushing of the piston to extrude the tube's contents might conceivably be done with the User's bare hands, it is more convenient - and nowadays it is also commonplace - to provide a small device, looking rather like a gun, into which the tube fits, and which includes a trigger-actuated piston rod that engages with the tube's piston end and, when operated, pushes the piston along in the tube, and thus ejects, or dispenses, the tube's contents in a controlled fashion.

One such dispensing gun device is described and claimed in Cox British Patent Specification No: 1,555,455, which relates to a particularly neat way in which the body of the the gun can be constructed out of simple sheet metal material. The present invention also relates to such a dispensing gun device, but to one - and a design for one - which is more conveniently constructed out of a plastics material by a moulding or extrusion process.

More specifically, the invention proposes a gun of this general type - that is, one which has a body formed of a framework comprised of a stock/handle, a muzzle and two parallel spaced elongate barrel members extending therebetween, the stock including a pair of spaced apertured support members into and though which is slidably mounted a piston rod to lie between the two barrel members, the body also including a piston rod drive member, a trigger pivotally mounted on the stock and having a piston-drive-member cam, means to bias the drive member towards the trigger's cam, and means for releasably locking the piston rod in place - wherein the handle/stock is a single sheet of material and the trigger member is a double sheet and fits over and either side of the handle/stock, to which it is pivotally mounted by a collared pin (or bush) extending within pivot holes (or apertures) in the stock/handle and the two trigger portions with the collar trapped between the two portions of the trigger.

In one aspect, therefore, the invention provides a dispensing gun of the described general type, wherein the handle/stock is a single sheet of material and the trigger member is a double sheet with its two portions spaced to fit over and either side of the handle/stock sheet and pivotally mounted thereto by a collared pivot pin extending within mating pivot holes in the stock/handle and the two trigger portions with the collar trapped between the two portions of the trigger.

The dispensing gun of the invention has a body of the generally conventional type, and it is not necessary to say much about that here, for in general principle it is all described quite well in, for example, the aforementioned Cox Patent Specification. Nevertheless it may be helpful to comment as follows.

The body, which is conveniently of an integral construction and formed, by a moulding or extrusion operation, of a plastics substance such as ABS (acrylonitrilebutadienestyrene), is formed of a framework comprised of a stock/handle, a muzzle and two parallel spaced elongate barrel members extending therebetween.

The whole framework is advantageously very "flat", with height and length but almost no depth (the barrel members are located at top and bottom, and the muzzle is desirably a small circle just big enough to take the nozzle of the tube whose contents are to be dispensed).

It can have stiffening ribbing around its periphery.

The stock includes a pair of spaced apertured support members; these apertured members are normal to the overall plane of the body, with the apertures aligned with the muzzle, and are merely big enough to accommodate the piston rod slidably mounted within them.

The piston rod is conveniently of metal - though it, too, could be plastic - and has a (detachable) larger-area pusher head at the end that contacts the tube's piston base and a hooked handle at the other end by which the User can manually pull it back.

The piston rod drive member is, very simply, a small apertured plate that fits loosely on the piston rod and can be pushed at one edge so as to tilt into frictional engagement with the rod, and then push the rod along. The trigger has a piston-drive-member cam that engages the plate edge, to tilt and push it, and the drive member bias means - conveniently a compression spring - biasses the plate towards the trigger's cam, so springing the trigger itself back into the unpushed state. Finally, the means for releasably locking the piston in place is simply another, similar biassed apertured plate, but working in the opposite direction (so that until it is released the piston rod is prevented from moving back out).

The invention provides a dispensing gun with a novel variety of trigger - more specifically, with an improved way of mounting the trigger. Thus, with a handle/stock which is a single sheet of material the invention proposes the use of a trigger member which is a double sheet and fits over and either side of the handle/stock sheet and is pivotally mounted thereto by a collared pivot pin extending within mating pivot holes in the stock/handle and the two trigger portions with the collar trapped between the two portions of the trigger. There are at least two ways in which this trapping of the collar can occur. In the first, the collar is physically located between one side of the stock/handle sheet and the facing trigger portion, the pivot pin passing through the pivot hole in the trigger portion on one side and both the pivot holes in the stock/handle and the other trigger portion on the other, while in the second the collar is located within a slightly larger pivot hole in the stock/handle and the pin's ends are located in the slightly smaller pivot holes one in each of the trigger portions. Both of these are discussed hereinafter with reference to the accompanying Drawings.

The trigger and the pivot pin can, like the body, be made from a plastic such as ABS. However, a material such as acrylic-reinforced ABS, which is stronger than the body's ABS, is preferred.

It will be evident that, once the trigger is in position either side of the stock/handle, it cannot slip off (because it is located in place by the pivot pin), and the pivot pin itself cannot slip out because in either direction its movement is constrained by the trigger portions and/or the stock/handle. Thus, in one embodiment the restraint in one direction is by the collar abutting the stock/handle while in the other direction the collar abuts the inside surface of the relevant trigger portion (which, of course, cannot itself move because it is "wrapped round" the stock/handle). In the other embodiment the restraint is by the collar (located within the stock/handle pivot hole) abutting one or other trigger portion on either side.

The two portions of the trigger are spaced sufficiently for them to be able to move freely across the stock/handle surface, but not to move far enough normal to that surface for them to disengage the pivot pin.

The trigger is like a doubled sheet - it has two portions joined at a common edge, just like a single sheet that has been folded in two (though the trigger is conveniently moulded or extruded in its doubled state, rather than folded over subsequently).

The handle can be forced into position on the pivot pin because its inherent flexibility allows the two portions to separate slightly, and so attain a sufficient spacing to pass over the two protruding ends of the pivot pin. The ease of doing this can be enhanced by providing the trigger at the appropriate places on its inner surfaces with shallow locating grooves that lead towards the pivot holes (these should become progressively more shallow towards the pivot holes); simply locating the trigger with the pivot pin at the start of these grooves, and then pushing the trigger onwards, drives it into place (the portions flexing outwards as it does so, and then snapping back as the hole proper is reached). Having the grooves become even shallow means that the trigger cannot so easily be pulled off again.

The pivot pin is collared - that is to say, it has a shallow flange extending around it (near one end in one embodiment, or near its centre in the other). The size of the flange is such as to stop the pin passing completely through the trigger portion's pivot holes, while its position (along the pin) locates the pin at the correct place so that a sufficient length projects either side of the stock/handle to hold the trigger securely mounted thereon.

An embodiment of the invention is now described, though by way of illustration only, with reference to the accompanying Drawings in which: Figure 1 shows a perspective view from above and behind of a dispensing gun of the invention; Figure 2 shows a side elevation view of the dispensing gun of Figure 1; and Figures 3A,B show in detail two alternative sectional views of the trigger part taken on the line 111-Il in Figure 2.

The dispensing gun shown in the Figures has a body (generally 11) formed of a framework comprised of a stock/handle (generally 12), a muzzle (13) and two parallel spaced elongate barrel members (14,14) extending therebetween. The stock 12 includes a pair of spaced apertured support members (151,15r) into and though which is slidably mounted a piston rod (16) to lie between the two barrel members 14. The body 11 also includes a piston rod drive member (17), a trigger (18) pivotally mounted (at 19) on the stock 12 and having a piston-drive-member cam (20), spring means (111) to bias the drive member 17 towards the trigger's cam 20, and locking means (112) for releasably locking the piston rod 16 in place. The handle/stock 12 is a single sheet of material; the trigger member 18 is a double sheet (with side portions 18f in the front, as viewed, and 18b at the back), and fits over and either side of the handle/stock 12, to which it is pivotally mounted by a collared pin (or bush) 19 (see Figure 3) extending within pivot holes (19h) in the stock/handle 12 and the two trigger portions 18f,18b with the pivot pin's collar (31: see Figure 3) trapped between the two portions of the trigger.

Figure 3 shops in section two alternative embodiments of the collared pivot pin/trigger/stock/ handle combination. In the first, the collar 31 is physically located between one side of the stock/handle sheet 12 and the facing trigger portion 18b, the pivot pin 19 passing through the pivot hole 19h in the trigger portion on one side and both the pivot holes in the stock/handle 12 and the other trigger portion 18f on the other, while in the second the collar 31 is located within a slightly larger pivot hole (19c) in the stock/handle 12 and the pin's ends are located in the slightly smaller pivot holes 19h one in each of the trigger portions 18f,18b.

As noted hereinbefore, it will be evident that, once the trigger 18 is in position either side of the stock/handle 12, it cannot slip off (because it is located in place by the pivot pin 19), and the pivot pin 19 itself cannot slip out because in either direction its movement is constrained by the trigger 18f,18b portions and/or the stock/handle 12.

Thus, in the Figure 3A embodiment the restraint in one direction is by the collar 31 abutting the stock/handle 12 while in the other direction the collar abuts the inside surface of the relevant trigger portion 18b (which, of course, cannot itself move because it is "wrapped round" the stock/handle). In the Figure 3B embodiment the restraint is by the collar 31 (located within the stock/handle pivot hole 19c) abutting one or other trigger portion 18f,18b on either side.

Claims

Claims 1. A dispensing gun of the general type as defined hereinbefore, wherein the handle/stock is a single sheet of material and the trigger member is a double sheet with its two portions spaced to fit over and either side of the handle/stock sheet and pivotally mounted thereto by a collared pivot pin extending within mating pivot holes in the stock/handle and the two trigger portions with the collar trapped between the two portions of the trigger.
2. A dispensing gun as defined in Claim 1, wherein the trapping of the collar is effected either by a structure in which the collar is physically located between one side of the stock/handle sheet and the facing trigger portion, the pivot pin passing through the pivot hole in the trigger portion on one side and both the pivot holes in the stock/handle and the other trigger portion on the other, or by a structure in which the collar is located within a slightly larger pivot hole in the stock/handle and the pin's ends are located in the slightly smaller pivot holes one in each of the trigger portions.
3. A dispensing gun as claimed in either of the preceding Claims, wherein the trigger and the pivot pin are made from acrylic-reinforced ABS.
4. A dispensing gun as claimed in any of the preceding Claims, wherein, to facilitate the handle being forced into position on the pivot pin the trigger is provided at the appropriate places on its inner surfaces with shallow locating grooves that lead towards the pivot holes, so that simply locating the trigger with the pivot pin at the start of these grooves, and then pushing the trigger onwards, drives it into place.
5. A dispensing gun as claimed in any of the preceding Claims and substantially as described hereinbefore.