EP0308322B1 - Indirect-acting fastening tool with powering adjustment - Google Patents

Description

The present invention relates to an indirect fire tampon sealing apparatus, comprising, in a barrel holder, a barrel, a piston mounted in friction in the barrel, to be driven in displacement, under the action of the combustion gases of a propellant charge housed in a load carrier integral with the barrel, and drive the buffer, a pawl mounted on the barrel holder, arranged to protrude into a groove of the barrel and retain the piston, and means for varying the volume of the combustion chamber, between the piston and the charge, and therefore the firing power, which comprise adjustment means, mounted movably relative to the barrel, and means projecting into the barrel arranged so that the displacement of the means of adjustment relative to the barrel causes the piston to move in the barrel.

The advantage of a sealing device actuated by a propellant charge, powder, is to be autonomous and to be able to have variable energy.

For this purpose, loads of different powers are often used.

It is also possible in indirect fire sealing devices to vary the power transmitted to the piston by varying the volume of the combustion chamber.

An apparatus of the type mentioned above by document FR-A-2 329 415 is already known. The apparatus of this document however has drawbacks. The power adjustment is done by rotating the cylinder head. The piston is positioned in the barrel, depending on the desired power, when the device is pressed to put it in the firing position. Therefore, it is created an additional effort which increases the support effort.

Document US-A-3,652,003 also teaches an apparatus of the same type, and which also has drawbacks. The adjustment means are mounted on the barrel holder and are intended to cooperate with a stop integral with the barrel and projecting from the barrel. When firing on certain materials, the piston can rebound and be propelled to the bottom of the barrel. In this case, the adjustment means no longer have any influence on the position of the piston in the barrel. When the apparatus is opened, the pawl no longer acts on the piston, or the relative position of the pawl and of the adjustment means is no longer taken into account, and the piston remains in the position of maximum power although the adjustment means can be in the intermediate power position. Correct positioning of the piston as a function of the desired power is therefore not always ensured in this device.

An apparatus of the type mentioned above is also known from document FR-A-2 218 168. It is, however, an apparatus with complex adjustment means. The positioning of the piston is carried out when the device is closed, the adjustment means are requested both at the opening and at the closing of the device and also increase the pressing force. These adjustment means include a spring that can cause variations in the power adjustment.

The present invention therefore aims to overcome the drawbacks of the prior art and to propose an apparatus, for sealing buffers, with a robust power adjustment system, easy to disassemble and with great regularity.

To this end, the present invention relates to an apparatus of the type mentioned above, characterized in that the piston comprises a head with an enlarged portion having a rear face, the adjustment means are mounted on the barrel and said means protruding in the barrel comprise a stop on which is provided a shoulder arranged to come into abutment against the rear face of the enlarged portion of the piston head, the abutment being free in translation and arranged for, in abutment on the rear side against the adjustment means , come to bear on the front side against the pawl arranged to position the piston in the barrel.

The invention also relates to an apparatus of the type mentioned above, characterized in that the adjustment means are mounted on the barrel and said means projecting into the barrel comprise a pin integral with the piston, arranged to bear on the side rear against the adjustment means, come to bear on the front side against the pawl arranged to position the piston in the barrel.

Preferably, adjustment means are mounted to be driven in rotation on the barrel.

Advantageously, the load carrier is arranged in the barrel, the adjustment means comprise a threaded ring mounted on the threaded rear part of the barrel and the axial distance separating the surfaces of the stop arranged to come into abutment respectively against the piston and the pawl is substantially equal to the axial distance separating the surface of the piston serving as support for the stop and the surface of the piston coming to bear against the pawl, preferably very slightly larger.

• la figure 1 est une vue en coupe axiale d'une première forme de l'appareil de l'invention, le canon étant tiré vers l'avant et la puissance étant réglée pour être maximale ;
• la figure 2 est une vue en coupe axiale d'une portion de l'appareil de la figure 1, le canon toujours tiré vers l'avant, le cliquet étant encore escamoté et la puissance venant d'être réglée pour être plus faible ;
• la figure 3 est une vue en coupe transversale selon la ligne III-III de la figure 2 ;
• la figure 4 est une vue de l'appareil des figures précédentes, avec arraché montrant, en coupe axiale, le verrou d'arrêt de la bague de réglage ;
• la figure 5 est une vue en perspective de la butée de réglage de puissance de l'appareil des figures précédentes;
• la figure 6 est une vue en coupe axiale du système de réglage de puissance de l'appareil des figures précédentes, après mise à feu et départ du piston, la puissance ayant été réglée pour être minimale, et
• la figure 7 est une vue en coupe axiale du système de réglage de puissance d'une deuxième forme de réalisation de l'appareil de l'invention.

The invention will be better understood using the following description of two embodiments preferred of the apparatus of the invention, with reference to the accompanying drawings, in which:

• Figure 1 is an axial sectional view of a first form of the apparatus of the invention, the barrel being pulled forward and the power being adjusted to be maximum;
• Figure 2 is an axial sectional view of a portion of the apparatus of Figure 1, the barrel still pulled forward, the pawl being further retracted and the power having been set to be lower;
• Figure 3 is a cross-sectional view along line III-III of Figure 2;
• Figure 4 is a view of the apparatus of the preceding figures, with cutaway showing, in axial section, the stop latch of the adjusting ring;
• Figure 5 is a perspective view of the power adjustment stop of the apparatus of the previous figures;
• FIG. 6 is a view in axial section of the power adjustment system of the device of the previous figures, after firing and departure of the piston, the power having been adjusted to be minimum, and
• Figure 7 is an axial sectional view of the power control system of a second embodiment of the apparatus of the invention.

The sealing apparatus, in its embodiment shown in Figures 1 to 6, comprises a barrel holder 1, of axis 20, in which is formed a loading opening 2, a barrel 3, mounted to slide in the holder -canon 1, between a rear position, against a cylinder head 4, in which is housed a not shown striker, and a front opening position. The rear part 5 of the barrel has a bore 6 for receiving a propellant charge, called a charge carrier, and it is tapped to receive by screwing a power adjustment ring 7. A piston 8, with a head with an enlarged portion 9 and a rod 10, is slidably mounted in friction in the barrel by means of a rod 11 surrounding the enlarged portion 9 of the piston 8. The barrel has a corresponding bore 16, with an annular radial shoulder 36 which can serve as a stop for the portion enlarged 9 of the piston 8. A buffer guide 12 is fixed, here by screwing, to the front of the barrel 3. A pawl 13 for retaining and repositioning in the firing position of the piston 8 is mounted on the barrel holder 1 and , under the action of return means, protrudes radially in the barrel 3 through a groove 14 formed in the barrel. A power adjustment stop 15, which will be described in detail below, is maintained between the adjustment ring 7 and the enlarged portion 9 of the piston 8.

The apparatus is intended to propel a tampon, not shown, to be introduced by the tampon guide 12, into a receiving material, by means of the piston 8 - it is an indirect-fire apparatus - intended to be driven towards the before by the combustion gases of an explosive charge placed in the housing 6. The housing 6 and the portion of the internal bore 16 of the barrel extending behind the piston 8 delimit the combustion chamber 44, of adjustable volume , as will now be discussed.

This adjustment is made by moving the ring 7 on the rear part 5 of the barrel. In reality, it is a relative displacement, because it is the barrel which must be moved in the ring. The latter is in fact immobilized in rotation by a boss 17 which can, on the other hand, slide axially in a groove 18 of the gun holder. The extreme rear position of the ring 7 on the barrel is here determined by a race limiting rod 19 mounted at the rear end of the barrel. To this end, the ring 7 has an internal milling 21 which can come into abutment on the rod 19.

A stop latch 22 is mounted on the barrel holder 1, to pass through its internal bore as well as the groove 18 and serve as a front stop for the boss 17 of the adjustment ring 7. The latch 22 thus avoids, during the opening the device, that the barrel, which is integral with the ring 7 with its boss 17, does not unexpectedly come out of the barrel holder 1, when the pawl is retracted.

A scale 23 of power levels is reported on cannon 3; it appears when the device is fully opened.

The power adjustment stop 15 is a generally rectangular piece freely mounted in axial translation in an extension of the groove 14 of the pawl. Symmetrical here, this part has two lateral ears 24 (there could therefore have been only one) extending between its front face 27 and a rear plane 28 and arranged to bear, by their upper faces on the Figure 5, on a flat 25 of the barrel. Significantly in its central part, the part 15 has a shoulder 26. The front face 27 of the stop 15 is intended to come into abutment against the pawl 13 in the retaining position and the barrel pulled forward; the shoulder 26 can come to bear against the rear face 29 of the enlarged portion 9 of the piston 8; the rear surfaces 28 of the ears 24 are intended to come into abutment against the annular front surface 30 of the ring 7. The flat 25 of the barrel extends between a transverse front shoulder 31 and a small rear shoulder 32, between which can move freely the ears 24 of the stop 15 and which therefore delimit its travel (Figure 6); behind the shoulder 32, a recess 33 has also been formed on the barrel for the rear part of the stop 15.

The stop 15, angularly fixed, is held radially in the barrel 3 by the extension of the pawl groove 14 and the inner surface 34 of the ring 7 (Figure 6).

The axial distance separating the surfaces 26 and 27 of the stop 15 is very slightly greater than the axial distance separating the rear face 29 of the enlarged portion 9 of the piston and its front face 35 intended to bear against the pawl 13 in the position of retainer and the barrel pulled forward.

Having described the structure of the various constituent elements of the device, its operation, and more particularly its power adjustment, can now be addressed.

It should first be noted that the power can be adjusted both with the barrel pulled forward and the device closed, although in this case it would be better to speak of variation in the volume of the chamber. combustion as adjustment, since the scale of power levels 23 is not visible.

A second remark must be made. When the power is adjusted, the barrel being pulled forward, the relative displacement of the barrel and the adjusting ring at the same time causes the desired positioning of the piston in the barrel, if it is a question of reducing the power. If it is to increase it, it is only after closing and reopening the device that the piston is positioned correctly. When the power is adjusted, the device being closed, the relative displacement of the barrel and the ring does not bring about the desired positioning of the piston in the barrel. It is only when the device is opened, which the operator must then do before closing it again, that the piston is positioned appropriately.

A third introductory remark is finally necessary. If the piston is not reassembled, and therefore the device is closed, and the adjustment is made, the operator must open the device, to position the piston at the end of the opening, before putting it on. close again.

Thus, in all cases, the desired positioning of the piston in the barrel takes place at the end of an opening phase of the device, at the moment when the adjustment stop, while the operator pulls the barrel towards the front comes to bear against the pawl.

To increase the power, that is to say decrease the volume of the combustion chamber, the pawl 13 is retracted from its groove 14 in order to be able to turn-unscrew the barrel 3 and advance it into the ring 7. To decrease power, we proceed in a similar way but to move back -screw- the barrel 3 in the ring 7. The relative position of the barrel 3 and the ring 7 being axially fixed, we release the pawl 13 which rises again in the barrel 3 through the groove 14. At the end of the piston positioning phase mentioned above, the front face 35 of the piston head is in abutment against the rear face 37 of the pawl, just like the front face 27 of the stop 15 against which the ring 7 is also in abutment. In this position of the elements of the apparatus, there is therefore a small clearance between the rear face 29 of the enlarged portion of the piston head and the shoulder 26 of the stop 15. And this is how the relative position piston and barrel, by means of the pawl, on the one hand, and the stop and the adjusting ring, on the other hand, is determined. When the device is subsequently closed, this position is not changed by means of the rod 11 of the piston head. During this closing, the stop 15 remains maintained between the rear face 29 of the enlarged portion of the piston head and the front face 27 of the ring 7.

The adjustment of figure 1 corresponds to the maximum power, the ring 7 being almost in rear stop on the rod 19, or the barrel 3 almost in front stop, by its ring 19, on the ring 7. The adjustment of figure 2 corresponds to a lower power, and that of FIG. 6, to an even lower power. The minimum power adjustment is carried out by screwing the barrel 3 into the ring 7 until the front face 27 of the stop 15, pushed back by the ring 7 in the extreme front position, comes practically to bear against the front shoulder. 31 of barrel 3 (Figure 6).

The function of the stop 15 therefore amounts to allowing the ring 7, by means of a radial projection, to move the position of the piston during the operation of the barrel by the operator, or to transform the rotational movement of the ring relative to the barrel in translational movement of the piston.

We saw above that, for example, by unscrewing the barrel, we increased the power. Of course, if the direction of the thread and the internal thread of the barrel and the adjusting ring were reversed, the rotation of the barrel causing the variation in power would also be reversed.

It will be noted that the stop 15 has been studied in its shape, in order, in the event of a sudden opening of the barrel, to reduce as much as possible the risks of rupture; it therefore has significant contact surfaces with the pawl 13 and the adjustment ring 7 and here works in compression between these parts.

The barrel 3 and the adjustment ring 7 of FIG. 6, almost identical to those of the preceding figures, are distinguished by the only fact that the rod 19 on the barrel and the milling 21 on the ring 7, as end means stroke, have been replaced respectively by a groove 40, formed in the barrel, receiving a ball 41 housed in a bore 42 of the boss 17 of the ring and intended to cooperate with the rear edge 43 of the groove 40 to prevent complete unscrewing of the barrel beyond its maximum power setting position.

The adjustment system of the apparatus of FIG. 7 differs from that of the apparatus of FIGS. 1 to 6 by the fact that the stop is a pin 15 ′ driven radially into the piston head 9 ′ arranged accordingly, the other parts of the device being identical to those of the device previously described. Apart from the fact that the piston head 9 ′ no longer has to cooperate directly with the pawl 13, but by means of the pin 15 ′, secured to the head, the operation of this latter device remains identical to that of the device of FIGS. 1 to 6. Thus, the positioning of the piston for determining the volume of the combustion chamber is effected, after positioning of the ring, when the pin 15 ′ is in contact, by its two opposite radial faces 27 ′ and 28 ′, with the pawl 13 and the ring 7, respectively.

Claims (9)

1. An indirect firing fastener driving apparatus including, in a barrel holder (1), a barrel (3), a piston (8) mounted in frictional contact (11) within the barrel, so as to be driven, under the action of the combustion gases of a propulsive charge housed in a charge holder (5), fast with the barrel (3) and drive the fastener, a pawl (13) mounted on the barrel holder (1), adapted to project into a groove (14) of the barrel and retain the piston (8), and means for varying the volume of the combustion chamber (44), between the piston (8) and the charge, and so the firing power, which include adjustment means (7), mounted so as to be movable with respect to the barrel, and means (15) projecting into the barrel (3) adapted so that movement of the adjustment means (7) with respect to the barrel causes movement of the piston (8) in the barrel (3) characterized in that the piston (8) has a head with enlarged portion (9) with a rear face (29), the adjustment means (7) are mounted on the barrel (3) and said means projecting in the barrel include a stop (15) on which a shoulder (26) is provided for coming into abutment against the rear face (29) of the enlarged portion (9) of the head of the piston (8), the stop (15) being freely movable in translation and adapted so that, bearing by the rear side (28) against the adjustment means (7), it comes into abutment, by its front side (27), against the pawl (13) adapted for positioning the piston (8) in the barrel (3).

2. Apparatus according to claim 1, wherein the stop (15) has at least one lug (24), extending between a front face (27), intended to come into abutment against the pawl (13), and a rear face (28) intended to come into abutment against the adjustment means (7).

3. Apparatus according to claim 2, wherein the enlarged portion (9) of the piston (8) has a front face (35), for engagement with the pawl (13), the distance separating the front face (27) of the lug (24) of the stop (15) and its shoulder (26) being substantially equal to the distance separating the front and rear faces (35,29) of the piston head (9).

4. An indirect firing fastener driving apparatus including, in a barrel holder (1), a barrel (3), a piston (8) mounted in frictional contact (11) within the barrel, so as to be driven, under the action of the combustion gases of a propulsive charge housed in a charge holder (5), fast with the barrel (3) and drive the fastener, a pawl (13) mounted on the barrel holder (1), adapted to project into a groove (14) of the barrel and retain the piston (8), and means for varying the volume of the combustion chamber (44), between the piston (8) and the charge, and so the firing power, which include adjustment means (7), mounted so as to be movable with respect to the barrel, and means (15′) projecting into the barrel (3) adapted so that movement of the adjustment means (7) with respect to the barrel causes movement of the piston (8) in the barrel (3) characterized in that the adjustment means (7) are mounted on the barrel (3) and said means projecting in the barrel include a pin (15′) fast with the piston (8) adapted so that, bearing by the rear side (28′) against the adjustment means (7), it comes into abutment, by its front side (27′), against the pawl (13) adapted for positioning the piston (8) in the barrel (3).

5. Apparatus according to one of claims 1 to 4, wherein the adjustment means (7) are mounted so as to be rotated on the barrel (3).

6. Apparatus according to one of claims 1 to 4, wherein the stop (15;15′) is mounted in an extension of the groove (14) of the pawl (13).

7. Apparatus according to one of claims 1 to 6, wherein the barrel holder (1) includes a forward check bolt (22) for the adjustment means (7).

8. Apparatus according to one of claims 1 to 7, wherein means (19,21;40,41) are provided for limiting the rearward movement on the barrel (3) of the adjustment means (7).

9. Apparatus according to one of claims 1 to 8, wherein the adjustment means include a threaded ring (7) screwed on the threaded rear part (5) of the barrel (3) and held against rotation in the barrel holder (1).

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