GB2171183A - Release mechanism incorporating delay and interlocks - Google Patents

Abstract

A release mechanism, for example a safety and arming unit for a weapon, includes a shutter 13 which is held against the force of a driving spring 22 at a first position spaced from a final or arming position for an actuator. Movement of the shutter 13 from the initial to the final position is prevented by an interlock 33,34 which is releasable only when the shutter 13 is rotated further away from the final position. The interlock is preferably released by means of an operating knob 16 having a cutout which obturates an over centre lever 41 for a detent. Movement of the shutter 13 away from the first position tensions the driving spring 22 and upon release of the detent the spring 22 drives the shutter 13 towards the armed position, under the control of escapements 27,28 which are coupled to the shutter 13 by a unidirectional drive coupling 29,30. The operating knob 16 is arranged to interlock with a cover 2 to provide effectively a second detent for the shutter 13. <IMAGE>

Description

SPECIFICATION Release mechanism incorporating delay and interlocks This invention relates to a release mechanism which incorporates a delay in its operation and at least one detent, preferably two detents, for inhibiting operation in the event of malfunction. The mechanism is particularly although not exclusively intended to constitute a safety and arming unit suitable for use, for example, with a manually or remotely fired anti-tank weapon. In its preferred from the invention provides a comparatively simple and reliable mechanism by means of which such a weapon can be safely emplaced nad brought to an armed state whilst providing sufficient time for an operator to remove himself a safe distance from the weapon before the armed state is attained and to enable the weapon to be redeployed if not fired.In the preferred embodiment the mechanism incorporates as stated above, two detents or interlocks and is generally arranged so that the failure of any single component prevents the attainment of an "armed" state.

However the invention may have a more general utility as a simple and convenient release mechanism.

The present invention is based on the use of a rotary carrier or shutter which is rotatable from an initial position, conveniently termed a safely position, in one direction towards a second position and is drivable, for example by a spring motor which is set or tensioned by movement of the carrier in the sense towards the second position, from the second position in the opposite direction past the initial position to a third or final position, which will normally constitute a position in which an actuator, carried by the carrier, must occupy for proper actuation. The actuator may comprise, for example, a gas motor, or protractor, which is operable to project a piston for actuating, by way of an interface of which the form may vary according to circumstances, a weapon to which the release mechanism is attached.An interlock or detent which prevents movement of the carrier from the first or initial position to the final, or arming position, is preferably arranged to be releasable only on movement of the carrier to the second position. This detent may be associated with a release lever which is obturated by an operating knob coupled to the rotary carrier and released for movement when the operating knob has been rotated to move the rotary carrier to the said second position.

Movement of the carrier to the second position preferably tensions a spring drive means and the drive means and the carrier may be coupled to a speed regulator, such as an escapement or clutter mechanism. Such a mechanism is preferably arranged so that a substantial period of time elapses for the driving of the carrier from the second to the final or arming position. This period of time may be of the order of five minutes or longer. The carrier may be coupled to the speed regulator by way of a unidirectional drive mechanism, such as an arrangement of pawls and ratchet wheels which permit relative movement of the carrier and the regulator only when the carrier is moved towards the second position.

In order to provide a second interlock, the operating knob may be arranged to engage a cover so as to inhibit removal of the cover on movement of the rotary carrier away from the initial position before the cover has been removed.

There follows a description with reference to the accompanying drawings of one embodiment of a release mechanism according to the invention.

Brief description of the drawings Figure 1 is a sectional view of a release mechanism according to the invention, showing most of the operative features thereof; Figure 2 is a sectional view on the line X-X through Figure 1; Figure 3 is an end view of the release mechanism from the left of Figure 1, a cover being in an open position; Figure 4 is a section on the line W-W through Figure 1; Figure 5 is a sectional view on the line V-V through Figure 3; Figure 6 is a section on a line T-Tthrough part of Figure 3, and shows a detail of a release knob for the cover; and Figure 7 is a sectional view on the line S-S through part of Figure 3, and shows a detail of an electrical terminal.

Description of the exemplary embodiment The present invention is, as indicated earlier, intended to form part of a weapon system which may consist of a tripod on to which a light anti-tank weapon is mounted and a safety and arming unit which interfaces with the anti-tank weapon. After deployment of the weapon the user is able, from a remote position, to fire the anti-tank weapon by the application of the correct electrical input. If the weapon be not fired it is possible for the user to disarm the weapon and redeploy as required.

However, the mechanism to be described is not limited to this application and since the construction and manner of operation of the weapon is not part of the present invention, it will not be described in detail.

Nevertheless, it is useful to say that the particular embodiment is intended to allow the emplacement and remote firing of a weapon by providing those features necessary or appropriate to protect the user from any hazardous event occuring during deployment or redeployment of the weapon system and also those features which are appropriate to bring the weapon to an armed, ready to fire, state as required.

The mechanism comprises a body portion 1 having at one end a hinged cover 2. The cover is shown both in solid section in Figure 1 to denote its closed position and also in chain lines to denote its open position to which it falls under the influence of gravity when a release knob (Figure 6) is operated.

At its other end the body 1 has a peripheral shoulder 3 for the support of a cover 4 which extends over the main moving parts of the mechanism.

Secured by bolts 5 (Figure 4) to the right-hand end face of the body 1 is a fixed yoke 6 which has spaced apart radially extending trunnions 7 and 8, each of which provides a journal 9, 10 respectively for radially extending portions 11 and 12 of a yoke 13 constituting a rotary carrier or shutter. At its lefthand end the yoke 13 is formed integrally with or secured to a shaft 14 extending through the body portion 1 to the left-hand end, at which it is fixed by a screw 15to an operating knob 16 disposed externally of the body portion 1. Before use of the mechanism the knob is enclosed by the cover 2 and, in a manner two be described, the operating knob interlocks with the cover.

The yoke 13 has a radial aperture in which an actuator 17 is mounted, preferably by screwthreaded engagement. In this embodiment of the invention the actuator 17 comprises a gas motor (or protractor) which is electrically operable to project a piston. Such a gas motor is of known construction and will not be described in detail. The actuator can be properly actuated only when the yoke 13 is in a position (called herein third or final position) in which the gas motor is aligned with a bore 18 in the body 1. This bore is closed by a nylon plug 19 which is ejected from the bore 18 when the gas motor actuates.

As mentioned previously, the release mechanism is interfaced with a weapon an for present purposes it is sufficient to state that the piston projected on actuation of the gas motor is used, by way of an interface of which the construction varies according to circumstances, to fire the weapon with which the release mechanism is associated. However, if the yoke 13 is not in the third or final position, the gas motor cannot be properly actuated.

In Figure 1 the yoke 13 is shown as in its third or final position, which in this embodiment is defined by an end stop 20 in the form of a pin located in the fixed yoke and extending into the path of the rotary yoke 13.

The end radial portion 12 of the yoke 13 includes a bore 21 forthe reception of one end of a coiled spring 22 which is supported on an extension 23 of a bush 24, which is fixed in the radial portion 8 of the fixed yoke and which provides a journal for the portion 12. The other end of the spring extends into an aperture 25 in an end plate 26 which is secured to an end flange 27 of the fixed yoke. The spring 22 is tensioned as the yoke 13 is moved clockwise (as viewed from the left).

Each of the trunnions 7 and 8 carries a clutter unit 27 and 28 respectively. These clutter units or escapements, which are preferably of known form, are each connected to a respective one of two ratchet wheels 29 and 30, which permit movement of the yoke 13 relative to the wheels only in the clockwise direction (as viewed from the left in Figure 1). For this purpose the ratchet wheels are each engaged by each of two pawls 31 and 32 secured to the yoke 13. This assembly allows the pawls to ride overthe ratchet wheels while the yoke 13 is rotated clockwise in the direction to tension the spring 22. When however the yoke 13 moves in the opposite sense, being driven bythe spring, the pawls engage the ratchet wheels which are constrained to move at a speed determined by the inert clutter units.

Before use of the release mechanism, the yoke 13 is not disposed in the third (hereinafter called zero degree position) as shown in Figure 1 but is held at an initial position, in this embodiment 25 clockwise from the zero degree position. This is the position for storage or transit of the mechanism. Referring now particularlyto Figure 5, the yoke portion 11 has a cutout 33 engageable with the end 34 of a detent pin 35 which is mounted in a sleeve 36 in a bore 37 extending through the wall of the body 1.The pin has a collar 38 and a helical compression spring 39 is disposed between the collar and the end of the sleeve so as to urge the detent pin into an interlock condition with the portion 11 of the yoke 13.At its outer end the detent pin is by means of a crosspiece 40 connected to a lever 41 which underlies the flange 42 of the knob 16. The lever provides a simple over centre action and if, it can be lifted from its position and swung through 1800, it provides by a simple cam action depression of the detent pin so that the obturating end portion 34 thereof is disengaged from the portion 11 of the rotary yoke 13.

As is most clearly shown in Figure 3, the operating knob 16 interlocks with the over centre lever for the detent pin. The interlock is only released when the operating knob is moved clockwise so as to rotate the yoke 13 from the 25 position by a further 35 (in this example) to a position (herein called the second position) in which the torque spring 22 is fully tensioned and a cutout 43 on the flange of the operating knob allows clearance for the over centre lever.

Figure 6 shows a detail of the securing knob 44 for the cover 2. it comprises a hollow body 45 with a radial flange 46. A securing bolt 47 extends axially through the body into the body 1 of the mechanism.

The body of the knob fits in a seat 48 in the cover. A helical compression spring 49 is located between the head of the bolt and the well in the body of the knob.

The seat is cut-away in a channel 50 (Figure 1)so that when the knob is pulled out against the force of the spring, the cover 2 faIls from the position shown in solid lines in Figure 2 to the position shown in chain lines.

Figure 7 illustrates a detail of an electrical connector secured to the wall of the body 1.

During transit and storage the yoke 13 is, in accordance with the foregoing description, maintained such that the gas motor or protractor is held 25 out of line from its armed position, the stored energy in the torque spring 22 holding the yoke against the detent pin. The detent pin is interlocked with the yoke such that removal of the detent and accordingly release of the yoke is not possible until the yoke has been rotated a further 35 to an end stop defining the so-called second position. This rotation introduces further stored energy into the driving spring 22. Only at this (60 ) position is it possible to overcome the mechanical interlock by the rotation of the over centre lever to move the detent out of the path of the shutter.

After the detent is removed, the torque applied to the yoke 13 drives the mechanism to the armed position. This movement is controlled to allow a period greater than five minutes to elapse before the yoke brings the gas motor to the zero degree position, that is to say the armed position. The period of time following the action of removal of the detent allows an operator to move a safe distance from the mechanism (and the weapon which it controls) before the armed state is reached.

The cover 2 remains in position until the arming sequence, as described above, is commenced, the withdrawal of the knob on the cover permitting the cover to open under the force of gravity. The cover also provides, in effect, a second detent which prevents the knob and accordingly the shutter from moving to the armed position if, for example, the other shutter detent becomes ineffective.

For example, if the yoke 13 should rotate from the transit (25 ) position, a cutout 51 in the operating knob enables the knob flange to engage a protrusion (not shown) in the cover 2. In this manner the cover cannot then be opened and further rotation of the yoke is prevented. This detent thereby inhibits movement ofthe yoke 13, and also, by prevention of the opening of the cover, indicates that the unit has effectively failed.

Claims (9)

1. A release mechanism including a rotary carrier for an actuator, the rotary carrier being movable from an initial position in a first direction to a second position and in a second direction to a third position, an interlock which inhibits the movement of the carrier from the first position to the third position, the interlock requiring movement of the carrier to the said second position for release, drive means adapted to be enabled by movement of the carrier to the said second position and means regulating the speed of movement of the carrier from the second position to the third position.

2. A release mechanism according to claim 1 in which the actuator can properly actuate only when the carrier is in said third position.

3. A release mechanism according to claim 2 in which the actuator comprises a gas motor.

4. A release mechanism according to any foregoing claim, wherein the said interlock comprises a detent engaging the said carrier to prevent rotation thereof from the first towards the third position, and a release lever which is obturated when the rotary carrier is in said first position but is movable to release the detent when the rotary carrier is in the second position.

5. A release mechanism according to any foregoing claim wherein the rotary carrier is rotatable by means of an operating knob.

6. A release mechanism according to claim 4 and claim 5 wherein the knob obturates the lever when the rotary carrier is in the first position and permits operation of the lever to release the said detent when the rotary carrier is in the second position.

7. A release mechanism according to claim 5 or claim 6 wherein the knob is adapted to engage a cover upon movement of the rotary carrier from the initial position before the cover is removed.

8. A release mechanism according to any foregoing claim wherein the drive means comprises at least one pawl and ratchet assembly coupling the rotary carrier to an escapement, the arrangement being such that the carrier can rotate uncontrolled by the escapement from the first to the second position but is controlled by the escapement during movement of the carrier from the second to the third position.

9. A release mechanism according to any foregoing claim, wherein the drive means comprises a spring motor which is tensioned by movement of the carrier towards the said second position.