US3344244A

US3344244A - Delayed-action tripping device

Info

Publication number: US3344244A
Authority: US
Priority date: 1965-07-23
Publication date: 1967-09-26
Anticipated expiration: 1984-09-26
Also published as: BE684513A; DE1578503A1; NL133937C; NL6509996A

Description

Sept. 26, 1967 c. METTLER DELAYED-ACTION TRIPPING DEVICE 3 Sheets-Sheet 1 Filed July 21, 1965 INVENTOR. 6244 40 M57745? BY :JM

Arrys'.

Sept. 26, 1967 c. METTLER DELAYED-ACTION TRIPPING DEVICE 3 Sheets-Sheet 2 Filed July 21, 1965 INVENTOR. 6421 a M7n 5Q C. METTLER DELAYED-ACTION .TRIPPING DEVICE 4 Sept. 26, 1967 3 Sheets-Sheet 5 Filed July 21, 1965 Arr/I544!!! INVENTOR.

64M 0 i/irrziie United States Patent O 3,344,244 DELAYED-ACTIGN TRIPPING DEVICE Carlo Mettler, Zurich, Switzerland, assiguor t Redon Trust, Chiasso, Switzerland Filed July 21, 1965, Ser. No. 473,612 3 Claims. (Cl. 20tl34) The present invention relates to improvements in de layed-action tripping devices and more particularly to pneumatic-actuated tripping devices suitable for firing explosive charges.

There are already known tripping devices fpr said purpose, but they are formed by a large number of small pieces, usually to be assembled in complicated way, what makes them diflicult and expensive to manufacture and their operation not as safe as desirable.

The present invention consists in a pneumatic delayedaction tripping device comprising a very limited number of sturdy, easily assembled pieces so as to result in an easy fabrication and a dependable operation.

Naturally the present invention can also be used for many applications other then the one said above, for instance for delayed-action switch or commutator controls and the like.

More precisely an improved tripping device according to the present invention comprises:

A casing or body member and a pressure plate extending over one side of said body member; a rigid diaphragm that separates in a hermetical way the space enclosed between said body member and pressure plate, in two chambers, in said diaphragm there being foreseen a guiding opening for a cylindrical hollow body, slidable therein, against the action of a spring, every time a pressure is applied to the pressure plate; a plunger means, slidable within said hollow body and adapted to actuate, directly or indirectly, the firing pin; a locking means for said firing pin, combined with a pneumatically operating means, and adapted to release the firing pin only when, upon an external pressure persisting on the pressure plate, in the two non-hermetic chambers there is established again the pressure balance that had been upset at the time of the displacement of said pressure plate.

The accompanying drawings illustrate schematically, in the way of examples, two forms of embodiment of the improved tripping device according to the present invention.

More precisely, in the drawings:

FIGURES 1 and 2 show respectively a plan view and a diametral section of a first form of embodiment of the tripping device according to the present invention, wherein the diiferent members are shown in their rest position.

FIGURE 3 shows in diametral section, the same device of FIGURES 1 and 2, however with the different members in the position in which they come to be as soon as the pressure plate has been lowered because of an external action.

FIGURES 4 and 5 show respectively, in a plan view and a diametral section, the same device as in the preceding figures, but wherein the different members are in the position they take up after the tripping.

FIGURES 6, 7 and 8 show, in a diametral section, another embodiment of the tripping device according to the present invention, and wherein the different members are respectively represented in the rest position, in the position they take up as soon as the pressure plate has been lowered, and finally in the position they take up after the tripping.

As it is apparent from the drawings, the form of embodiment illustrated in the FIGURES from 1 to 5 comprises: a body or casing 1, made of rigid material, closed on top by a cover or pressure plate 2, connected to the upper edge of the casing 1 by means of a flexible and gas-tight element 2'. The inside of the space enclosed between the casing 1 and the cover 2 is divided in two chambers by a rigid diaphragm 3, having in its center a hole adapted to constitute a seat, with a certain play, for the sliding hollow stem or cylinder 2a, fast with the pressure plate 2. Inside the cavity of said stem 2a there are received a helical spring 4, and a small plunger 5, the cylindrical wall of the stem 2a having at a given point an opening 2d, the purpose of which shall be explained later.

Beneath the plunger 5, that terminates at its bottom with a conical tip, there is arranged the tripping member 6, carrying the firing pin, and combined with the locking lever 7, pivoted in O, and an arm whereof is provided with a tooth 7b which, through an aperture foreseen in the stem 2a, is in contact with the wall of the stem itself. The other arm of said lever carries at its end a tooth 70 which, in the rest position, keeps the tripping member 6 in a cocked position, that is the firing pin a distance away from the percussion cap 9, arranged in the wall of the casing or body 1.

With the lever 7 there is combined a bladder or lung 8, of a flexible and elastic material, filled with air, and communicating with the upper chamber of the device in question.

Before its operation, the different members of the tripping device being the object of the present invention are in the position clearly illustrated in the FIGURES 1 and 2, and under these conditions said tripping device or igniter may be placed in the ground with cover 2, near the surface, now in a raised position, as it can be seen in FIGURE 2. In this position, which is the normal one, the spring 4 does not carry any load and the bladder 8 has its natural shape. As already stated the locking lever 7 cannot rotate about its pivot 0 because its tooth 7b is in contact with the stem 2a of the pressure plate 2, and consequently the tooth 7c of said lever keeps the tripping member 6 in its cocked position as shown in FIG. 2.

At the instant when (see FIG. 3) on the cover or pressure plate 2 of the device comes to bear a load or a pressure P equal or higher than the predetermined actuating load, the cover 2 is brought down until it bears on the diaphragm 3. In such a position, the spring 4 is pressed down and bears on the small plunger 5 which, in turn, acting on the inclined plane of the tripping member 6, tends to push this last one towards the percussion cap 9. The locking lever 7, pushed in turn by the tripping member 6, tends to rotate since its tooth 7b succeeds in penetrating into the opening 2d existing on the stem 2a of the pressure plate 2, but to lock it, intervenes the bladder 8 which, because of the sudden lowering of the pressure plate 2, and the consequent volume reduction of the air enclosed between it and the diaphragm, becomes inflated, opposing the displacement of the lever 7.

If the load or pressure P, bearing on the pressure plate 2, is instantaneous, that is due to a shock, a pressure Wave caused by near explosions or the like, once the stress is over, the spring retrieves upwardly the pressure plate 2 and all the components of the firing device return in the exact initial or rest position, as shown in the FIGURES 1 and 2.

If instead the load P persists on the pressure plate 2 (FIGURES 4 and 5) then, a few instants after the application of said load, the compressed air contained above the diaphragm 3 leaks through the clearance existing between the guiding cavity, fast to the diaphragm 3 and the stem 2a of the pressure plate, as long as there is reached a perfect balance between the pressure of the air contained above and that contained below the diaphragm 3. Once said balance is reached, the bladder 8 presents no resistance anymore to its crushing and accordingly the locking lever 7 rotates about its pivot 0, thus disengaging its tooth 70 from the tripping member 6 which, under the thrust of the spring 4, will snap sliding horizontally and bringing the firing pin fast with same against the percussion cap 9, thus causing its firing.

The form of embodiment illustrated in the FIGURES 6, 7 and 8 is different from the one described above although having the same basic members.

Indeed, the device as illustrated in said figures comprises: a casing or body 11, a cover or pressure plate 12, connected with the upper edge of the casing 11 through an elastic ringshaped means 12a closing it hermetically. The inner space thus resulting is divided in two parts by the rigid diaphragm 13, which has in its center a guiding hole or sleeve 13a, within which extends and slides the hollow cylindrical element 15 in the inside whereof are received a helical spring 14, and the tripping member 16, which in this instance has the shape of a cylinder or small plunger carrying at'its lower end the firing pin adapted to hit the percussion cap 19, arranged in the bottom of the casing 11. On a section of the extension 13a of the diaphragm 13 there is pivotally connected the locking lever 17, through its pivot O. Laterally to same, in the diaphragm 13 there is foreseen a hole 1%, with guiding walls, within which slides the small piston 18. The rod of said piston has a hole wherein there is inserted, so as to be able to effect some oscillations, the tail 17a of the lever 17, so that the piston 18 controls the movements of the lever 17, that is allowing same to carry out or not the rotation about its pivot O, as it will be better explained later.

The lever 17 further has also a tail 17b which, in the rest position, is in contact with the inner wall of the hollow plunger 15, and opposite its tail 17a a tooth 170, which is the element of said lever locking the tripping member 16 in a position away from the percussion cap 19, until the time when the blasting has to occur.

The operation of the above described device is practically the same as that of the preceding device. Indeed, when said device is in its rest position, the pressure plate 12 is in a raised position, the spring 14 is not pressed, and the piston 18 is in its lowered position. As already mentioned, in this position of the mechanism, the lever 17 is prevented from rotating about its pivot since its tooth 17b is in contact with the outer wall of the hollow element 15, and therefore the tooth 17c keeps the tripping member 16 cocked and thus away from the cap 19.

At the instant when (FIG. 7) on the pressure plate 12 comes to bear a load P equal or higher than the calibratron load, said pressure plate drops down until it rests on the diaphragm 13, thus compressing the spring 14 and this, hearing on the tripping member 16, tends to rotate the locking lever 17. But, at this first instant said lever is prevented from rotating because the air contained above the diaphragm 13 has been compressed and bears with a pressure higher than that in the rest condition on top of the piston 18, thus preventing any movement of the locking lever 17, to which it is connected.

If the load P bearing on the device is an instantaneous one, once the stress is over, all parts return in the rest position as shown in FIG. 6.

If instead the load or pressure P persists (FIG. 8), then after a few instants there is established again a balance between the pressures in the two chambers, above and below the diaphragm 13, whereby, persisting on the tripping member 16 the pressure exercised by the compressed spring 14, and no overpressure being applied anymore on top of the piston 18, this can move upwardly, allowing the lever 17 to rotate about its pivot O, whereupon the tooth 17b will enter into the opening a foreseen on the body '15 wall, and the tooth 17c will become disengaged from the tripping member 16 which, under the action of the spring 14, will hit the percussion cap 19.

From the above description it is apparent how the delayed-action tripping devices, object of the present invention, ofier remarkable advantages as compared to similar already known devices. Indeed they are constituted by few very sturdy elements, easy and cheap to manufacture, and of safe operation, just because of this simplicity of theirs and for the fact of not including elements capable of deteriorating with the time.

Of course, the two devices as illustrated and described above have merely an illustrative character and by no means a limiting one, and therefore the different elements constituting them, the materials used for their manufacture, and all the constructive details may vary according needs without therefore departing from the field of the present invention.

What I claim is:

1. A delayed-action tripping device, inoperative by sudden instantaneous stresses, which comprises, in combination a rigid casing enclosure and a pressure plate, with a flexible portion of said plate hermetically sealing said enclosure, a rigid diaphragm provided with a hole, said diaphragm dividing said enclosure into two non-airtight chambers; a slidable element, sliding into a hole in said diaphragm and actuated by the pressure plate against the bias of a spring; a tripping member; a locking means for locking said tripping member in its non-tripping position; and a delayed time means, said time means and said diaphragm being subjected to the prevailing pressure in either of the two chambers resulting from the pressure applied to the pressure plate, said delay means acting on said locking means allowing the locking means to be released from the tripping member only when persisting pressure is applied to the pressure plate.

2. A tripping device as claimed in claim 1, and comprising: a pressure plate provided with a hollow stem, extending through and capable of sliding in a corresponding hole of the diaphragm; a spring and a guiding plunger with a conical tip, received and slidable in the cavity of said stem; a tripping member, provided with an inclined plane on which rests and bears the conical tip of said plunger; a locking means formed by a two arm lever, one of the arms whereof being provided with a tail bearing in normal position-on the outer surface of said stem and adapted to penetrate in an opening provided on said stem itself, at the instant of its tripping, while the other arm is provided with a latching tooth, engaged with the tripping member and urged in its locking position, by an elastic bladder, the inside whereof is communicating with the chamber above the diaphragm, so that said bladder is filled with air under pressure at the first instant, after the lowering of the pressure plate, while, should the load on said plate persist, the balancing of the pressures in the two chambers separated one from the other in a non airtight way by the diaphragm, occurs, the pressure inside the bladder decreases and it does not oppose anymore the movement of the lever causing the release of the tripping member.

3. A tripping device as claimed in claim 1, in which the pressure plate rests on a cylindrical hollow element, closed at its top, and receiving in its cavity the tripping member, and a spring, bearing on said member, with this member there being combined a locking lever, pivoted in an intermediate point thereof and provided, at one of its ends, with a tooth adapted to normally keep in a cocked position the tripping member, and at its other end a first tail portion, in contact with said cylindrical element when the lever is in its rest position, and a second tail portion engaged with the delayed time element, constituted by a piston slidable in an opposite seat provided in the diaphragm, and subjected to the pressure prevailing in the chamber closed by the pressure plate.

(References on following page) 5 5 References Cited FOREIGN PATENTS UNITED STATES PATENTS 948,276 1/1964 Great Britain. 2,465,009 10/1945 Chase 102-16 I 2,857,842 10/1958 Mahn 102 8 BERNARD A. GILHEANY, Pnmary Elamzner.

3,098,439 7/1963 Berger 102-8 5 H. E. SPRINGBORN, Assistant Examiner.

Claims

1. A DELAYED-ACTION TRIPPING DEVICE, INOPERATIVE BY SUDDEN INSTANTANEOUS STRESSES, WHICH COMPRISES, IN COMBINATION A RIGID CASING ENCLOSURE AND A PRESSURE PLATE, WITH A FLEXIBLE PORTION OF SAID PLATE HERMETICALLY SEALING SAID ENCLOSURE, A RIGID DIAPHRAGM PROVIDED WITH A HOLE, SAID DIAPHRAGM DIVIDING SAID ENCLOSURE INTO TWO NON-AIRSIGHT CHAMBERS; A SLIDABLE ELEMENT, SLIDING INTO A HOLE IN SAID DIAPHRAGM AND ACTUATED BY THE PRESSURE PLATE AGAINST THE BIAS OF A SPRING; A TRIPPING MEMBER; A LOCKING MEANS FOR LOCKING SAID TRIPPING MEMBER IN ITS NON-TRIPPING POSITION; AND A DELAYED TIME MEANS, SAID TIME MEANS AND SAID DIAPHRAGM BEING SUBJECTED TO THE PREVAILING PRESSURE IN EITHER OF THE TWO CHAMBERS RESULTING FROM THE PRESSURE APPLIED TO THE PLATE, SAID DELAY MEANS ACTING ON SAID LOCKING MEANS ALLOWING THE LOCKING MEANS TO BE RELEASED FROM THE TRIPPING MEMBER ONLY WHEN PERSISTING PRESSURE IS APPLIED TO THE PRESSURE PLATE.