WO1998048235A1

WO1998048235A1 - Recoil absorbing device

Info

Publication number: WO1998048235A1
Application number: PCT/SE1998/000647
Authority: WO
Inventors: Leif Cernold
Original assignee: Leif Cernold
Priority date: 1997-04-22
Filing date: 1998-04-08
Publication date: 1998-10-29
Also published as: SE506717C2; SE9701498L; AU7091698A; SE9701498D0

Abstract

The present invention comprises a recoil absorbing device for firearms of the type that include a forward, barrel bearing, part (1) and a rear part (2) which forms an anchorage or support for the forward part, in which, on firing, the forward part is displaceable in relation to the rear part in line with the barrel and against the resistance of the recoil absorbing device. The recoil absorbing device includes a driver (6) connected with the forward part (1), a link mechanism (7), a counterweight (8) which is displaceable in line with or parallel to the barrels length, and a return mechanism (14, 15). Both the driver (6) and the counterweight (8) are in communication with the link mechanism (7) in such a way that when the weapon is fired the resulting recoil of the barrel causes the driver to activate the link mechanism which in its turn accelerates the counterweight in the opposite direction to the barrels' recoil motion. After firing the return mechanism (14, 15) returns the recoil absorbing device and the forward part (1) to their original positions.

Description

RECOIL ABSORBING DEVICE

The present invention comprises a recoil absorbing device for firearms of the kind that include a forward, barrel bearing, part and a rear part which forms an anchorage or support for the forward part, in which, on firing, the front part is displaceable in relation to the rear part, in line with the barrel, against the resistance of the recoil absorbing device . State of the art

When firearms are fired a powerful recoil results, this applies equally for hand held weapons, such as rifles and pistols, as for artillery pieces. Recoil absorbing devices of the kind mentioned above were known of previously and have been used to reduce this recoil effect. In its simpliest form a recoil absorber can comprise a spring which works to force the forward and rear parts apart. However, such a simple recoil absorber has a very limited effect. There also arise oscillations in the spring that necessitate its combination with some kind of shock absorber if it is to work satisfactorily. Gas or fluid filled shock absorbers have the added disadvantage that their seals begin to leak after a time, be they used often or seldom, and, therefor, such a system is not maintenance free but must be periodically serviced or replaced. As examples of such recoil absorbing devices which work with the help of a spring in one way or another can be mentioned U.S. patents 3 604 138, 3 754 344 and 4 910 904.

Another type of recoil absorber for rifles is known through U.S. 3 795 998 with which absorbing is achieved through brake discs equipped with a rack and pinion mechanism. The disadvantage with such a recoil absorber is that it is costly to produce and install and that its complicated assembly makes it awkward to handle and maintain. Short description of the invention

The present invention aims at overcoming the problems and disadvantages with previously known recoil absorbing devices for firearms. The invention aims specially at creating a recoil absorber which has a good absorbing effect, is simple, cheep to construct, is maintenance free and is easy to handle. These aims are met, at the very least, by means of a recoil-absorbing device according to claim 1. Another aim of the submitted design of the invention is that the counterweights mass should be as little as possible whilst achieving a good recoil absorbing effect. This aim is met by means of a recoil-absorbing device according to claim 2. The invention is based primarily on the insight that a recoil absorbing device with the above aims and characteristics can be attained through the inclusion of a counterweight which accelerates in the opposite direction to the recoil movement of the barrel aided by a driver, attached to the forward part or barrel, which activates a link mechanism which in its turn transfers and converts the barrels backwards motion to a forward motion of the counterweight .

The following drawing and description detail an embodiment in which the invention is incorporated within the butt of a rifle. It is fully possible, however, with the correct form and dimensions, to utilise the invention on e.g. artillery pieces. In such a case it would be more practicable to mount the recoil absorber to the side of the barrel and the driver could be in the form of e.g. a lug attached to the barrel .

In the design shown the link mechanism takes the form of a lever mechanism which rotates on a shaft in the rear part. The link mechanism can take many forms, however, including any mechanism that is capable, in one way or another, of transforming the barrels backward motion into a forward motion of the counterweight. In preference the link mechanism should be geared so that the counterweights movement, speed and acceleration forward are greater than the barrels movement, speed and acceleration backwards. Thus the counterweights mass can be held advantageously low. This can be easily achieved with a lever mechanism by having unequal lever arms on either side of the pivot. It would even be simple to make a recoil absorber with variable effect by making the pivot adjustable between different positions on the lever thus altering the respective lengths of the lever arms. To function, the recoil-absorbing device is dependent upon some kind of return mechanism that resets the device into its start position after every shot. In the embodiment shown this return mechanism comprises two helical springs. The main reason for having two springs is to maintain good balance in the recoil absorber without the risk of jamming. The springs spring power is so low as to have negligible influence on the recoil absorbing. On firing, therefor, the counterweight will strike the back plate of the forward part giving a shock to the weapon that is neither experienced as uncomfortable by the shooter nor has a negative influence on the shots result because the shock is directed forwards in line with the barrel. Naturally the return mechanism can take many other forms than two helical springs, e.g. in the embodiment shown, one helical spring would suffice, more exactly, that between the weapons forward part and the counterweight which works to force the counterweight towards the link mechanism. Short description of the drawing Shown in the drawing are in

Fig. 1 a longitudinal section through a rifle butt, the rear part of which houses a schematically shown embodiment of a recoil absorbing device according to the present invention. Detailed description of a preferred embodiment

The only figure shows a longitudinal section through a rifle butt. The rifle butt is divided into two parts, more exactly, a forward part 1 that bears a not shown barrel and trigger mechanism. 2 indicates a rear part that, in its normal position, is separated from the forward part by a space 3. Further, the rear part 2 forms a support surface 4 that, under firing, is intended to be held against the shooters shoulder. The recoil absorbing device comprises a body 5, a push rod 6, a rocker or lever 7, a counterweight 8 plus a guide collar 9. The recoil absorber is largely housed in the rear part of the butt 2 and will for the most part be unseen from the outside. Only a small part of the push- rod 6 and guide collar 9 will be visible in space 3 because each of these are fixed to the rear edge of the forward part and, more exactly, are arranged so that they are essentially in line with or parallel to the barrel. The body 5 is fixed to the rear part 2 by means of screws, pegs or similar through holes 10. The lever 7 is articulated with the rear end of the body 5 by (and rotates around) the pivot 11. Further, the body exhibits two guides 12 for the push rod and one guide 13 for the counterweight 8. A tube welded to the body is a suitable construction for all of these guides through which the push-rod or counterweight are displaceable forward and back. Guide collar 9 has an outer dimension suited to be insertable into guide 13 which also then becomes a guide for the guide collar 9 as these have a telescopic relationship to each other. It is evident from Fig.l that the counterweight is made up of two parts with differing diameters, the rear part that is preferably precisely fitted to guide 13 and the forward part that is precisely fitted to guide 9. 14 and 15 indicate two helical springs acting as relocating or return springs. Return spring 14 is situated within the guide collar between the rear edge of the front part and a recess 16 in the front end of the counterweight and works to force the counterweight back against the lever 7. Return spring 15 is placed around push rod 6 and stretches between stop block 17 and the front end of guide 12 and thus works to force the body 5 backwards in relation to the push rod 6 i.e. to separate the rear part of the butt 2 from the front part 1. Stop block 18 defines the rear limit for the rear part 2.

As is evident from Fig.l lever 7 has two lever arms, 7' and 7", of unequal length and opposing direction in relation to the shaft 11. More exactly, in the preferred embodiment shown, the moment of leverage between the push rod 6 and shaft 11 is approximately half the moment of leverage between the counterweight 8 and shaft 11. When the weapon is fired the following happens:

Because of recoil the barrel and the forward part of the butt 1 press against the shooter and the rear part of the butt 2. The push-rod 6 causes the lever 7 to rotate clockwise on the shaft 11 and as a result of this the counterweight 8 accelerates to the left in Fig. 1 towards part 1 of the butt in a direction in line with or parallel to the barrel. As a result of the differing lengths of lever arms 7' and 7", which have a ratio 2:1, the counterweight 8 will be displaced twice as far and with twice the speed and acceleration in relation to the compression effect on the parts 1 and 2 of the butt. With a sufficiently powerful recoil the front end of the counterweight 8 will strike against the rear edge of the forward part of the butt and give that a shock forwards in the direction of the barrel. After firing the return springs 14 and 15 work together to bring the shock absorbing device back to its original position, with its various parts pressed close against each other without any play. Possible modifications to the invention

It is evident that the invention can be modified in many ways within the framework of the following claims. The constituent parts of the recoil-absorbing device can e.g. be given another form or be repositioned. As mentioned earlier it is not essential to have two springs 14, 15 , one would suffice. Further, it is naturally possible to cover the space 3 with a sleeve from either the forward 1 or rear 2 part of the butt.

Claims

1. Recoil absorbing device for firearms of the kind that comprise a forward, barrel bearing part (1) and a rear part (2) that forms an anchorage or support for the forward part, in which, on firing, the forward part is displaceable in relation to the rear part in line with the barrel and against the resistance of the recoil absorbing device, c h a r a c t e r i s e d in that it includes a driver (6) connected with the forward part (1), a link mechanism (7), a counterweight (8) that is displaceable forwards and back in a direction essentially in line with or parallel to the length of the barrel, and a return mechanism (14, 15), in which both the driver (6) and counterweight (8) are in communication with the link mechanism (7) in such a way that when the weapon is fired the resulting recoil of the barrel causes the driver (6) to activate the link mechanism (7) which in its turn accelerates the counterweight (8) in the opposite direction to the barrels recoil motion, whereafter the return mechanism (14, 15) returns the recoil absorbing device and the forward part (1) to their original position.

2. Recoil absorbing device in accordance with claim 1, c h a r a c t e r i s e d in that the link mechanism

(7) has a gear ratio so that the movement of the counterweight (8) is greater than the displacement of the forward part (1) in relation to the rear part (2) .

3. Recoil absorbing device in accordance with claim 1 or 2, c h a r a c t e r i s e d in that the link mechanism comprises a lever (7) that is rotatable on a shaft (11) and has lever arms (7', 1") that protrude in differing directions from the shaft (11) .

4. Recoil absorbing device in accordance with claims 2 and 3, c h a r a c t e r i s e d in that the gear ratio is achieved through unequal moments of leverage between the direction of attack of the driver (6) and the shaft (11) in respect to the direction of attack of the counterweight (8) and the shaft (11).

5. Recoil absorbing device in accordance with claims 2-4, c h a r a c t e r i s e d in that the gear ratio is adjustable.

6. Recoil absorbing device in accordance with claim 5, c h a r a c t e r i s e d in that the gear ratio is adjustable by means of moving the position of the shaft

(11) ΓÇó 7. Recoil absorbing device in accordance with any of the previous claims, c h a r a c t e r i s e d in that the firearm is a rifle that has a butt with a forward part (1) and a rear part (2) which are displaceable in relation to each other.