GB2246619A

GB2246619A - A safety device for a hydrostatic triggering mechanism.

Info

Publication number: GB2246619A
Application number: GB9114239A
Authority: GB
Inventors: Harmut Gessler; Bernhard Kratz
Original assignee: Diehl GmbH and Co
Current assignee: Diehl Verwaltungs Stiftung
Priority date: 1990-07-04
Filing date: 1991-07-02
Publication date: 1992-02-05
Anticipated expiration: 2011-07-02
Also published as: GB9114239D0; DE4021319C2; DE4021319A1; GB2246619B

Description

1 A SAFETY DEVICE FOR A HYDROSTATIC TRIGGERING MECHANISM The invention

concerns improvements relating to safety devices for example, for or in a triggering mechanism, such as a mechanism for triggering a switching function at a specific hydrostatic pressure. An example of such a triggering mechanism is described in our older -ion P 40 14 826.2, and has a drive Patent Applicall.. mechanism with a toothing, a coupling toothed wheel which is displaceable between a passive operating position and an active operating position and in each operating position meshes with the toothing of the drive mechanism, and a transmission toothed wheel -,7hi4ch, upon appropriate pressure impingement on the --r--'aaer--ng mechanism until the pressure equalisation, is in meshing engagement with the coupling toothed wheel.

US-A44 87 126 discloses a triggering mechanism which is provided more especially for an underwater mine. As a result of its construction this known triggering mechanism can be activated not only by the action of a specific hydrostatic pressure, but possibly also by an appropriate pneumatic pressure impingement. The safety behaviour of this triggering mechanism accordingly still leaves something to be desire.

Known from DE 31 33 364 C2 is a switch for an 2 electrical fuze of a projectile which between the firing and the detonation breaks through the surface ofthe water, the switch being designed with a displaceable element which is loaded by a spring and which actuates a contact. There the displaceable element contains a pressure pick-up, arranged on the end face of the projectile casing, for the dynamic pressure. As a result of its construction this switch, with respect to safety criteria in specific loading states of the switch, still leaves something to be desired.

A fuze for an underwater projectile with a first switching pin which is spring-loaded in the longitudinal direction of the projectile against the dynamic pressure of the water and which upon exit of t-he projectile from the water actuates an electrical contact for an ignition detonation criterion is known from the DE 37 1-3 414 C2 of the applicant. In the case of this fuze a second switching pin is mounted so as to be d isplaceable in the direction of the longitudinal axis of the projectile, which pin upon target impact of the projectile as a result of its mass moment of inertia actuates an electrical contact for a second ignition detonation criterion.

The problem underlying the invention is to provide a safety device which is reliably effective in all possible or conceivable loading states of the associated triggering mechanism.

i i 1 1 i i i i 1 1 i In accordance with the invention there is provided a safety device for a triggering mechanism (for triggering switching function at a specific hydrostatic pressure) which has a drive mechanism with a toothing, a coupling toothed wheel which is displaceable between a passive operating position and an active operating position and in each operating position meshes with the toothing of the drive mechanism, and a transmission toothed wheel which, upon appropriate pressure impingement on the triggering 10 mechanism until the pressure equalisation, is in meshing engagement with the coupling toothed wheel, characterised in that two safety switches which are independent of one another and which are in each case displaceable between a passive position and an active position are provided, in that a force element 1-s provided for the actuation of the first safety switch, in that the second safety switch is provided on a time delay mechanism which is connected to the triggering mechanism, and in that the first safety switch is provided for the locking or respectively no releasing of the triggering mechanism and of the time delay mechanism.

The advantage achieved with the safety device in accordance with the invention consist more especially in that e.g. upon interruptions of the arming criterion during the arming period of time defined by the safety device a resetting of the arming procedure is automatically effected, and in that a coupling function of the arming criterion is given to a time member of the 4 safety device, whereby the arming upon an interruption of the arming criterion definitively remains interrupted.

Preferably, the first safety switch has a slider element which is associated with the force element and which is guided linearly along a guide mechanism or is respectively secured by means of a shear pin on the guide mechanism; and the guide mechanism is provided with at least one end stop for the slider element, against which the slider element butts, with the force element activated, for the first safety switch in the active operating position.

The slider element preferably has a slider nose and a slider extension, in which respect in an inactive position of the force element, the slider nose serves for the torsionally-fast restraining of the coupling toothed wheel and the slider extension serves for the restraining of the time delay mechanism.

Preferably, the time delay mechanism has a toothed wheel with a recess, in which in the inactive operating position the slider extension is disposed for the torsionally- fast restraining of the toothed wheel; and the toothed wheel of the time delay mechanism is provided with an end stop for the actuation of the second safety switch.

A spring is preferably secured with its one end 1 1 1 1 i i j i portion on the toothed wheel of the time delay mechanism, the second end portion thereof being arranged f ixedly on the housing of the safety device, in which respect the spring pre-loads the toothed wheel of the time delay mechanism in a direction of rotation which is opposite to the direction of rotation in which the toothed wheel of the time delay mechanism is driven by the drive mechanism by way of the coupling wheel and the transmission wheel in the appropriate operating position.

Each of the two safety switches preferably has a fixed switch part and a switching member which is movable with respect to the fixed switch part, and preferably each switch part has two pairs of contacts and each switching member has two contact bridges.

The safety device in accordance with the invention for a triggering mechanism is used preferably in the case of sea mines, and the invention includes and provides such a triggering mechanism and/or a sea mine incorporating the safety device.

Further details, features and advantages will become apparent from the following description of an exemplified embodiment, indicated in the drawings, of the safety device in accordance with the invention for a triggering mechanism provided for triggering a switching function at a specific hydrostatic pressure.

6 FIGURE 1 shows partially longitudinally sectioned a triggering mechanism, provided f or triggering a switching function at a specific hydrostatic pressure, jointly with the safety device, FIGURE 2 shows a top view of the essential parts of the 1 time-delay mechanism, consisting of a toothed wheel and a second safety switch, FIGURE 3 shows a three-dimensional spatial representation of the second safety switch, FIGURE 4a shows a three-dimensional representation of the first safety switch of the safety mechanism in accordance with FIGURE 1 jointly with a force element and a slider element in the passive switching position, FIGURE 4b shows a three-dimensional representation, corresponding to FIGURE 4a, in the active switching position, FIGURE 5 shows a three-dimensional representation of the first safety switch shown in FIGURES 4a and 4b, consisting of a fixed switch part and a movable switching member, FIGURE 6 shows a sectional representation of the fixed switch part and of the movable switching member of the first or respectively of the second safety switch in accordance with FIGURE 3 or respectively in accordance 1 1 1 1 i i 1 1 i i 1 1 1 1 1 1 1 1 i i i 7 with FIGURE 5, FIGURE 7 shows a front view in line of sight of the arrow VII in FIGURE 6, and FIGURE 8 shows a block circuit of important, components of the safety device in accordance with FIGURE 1.

FIGURE 1 shows, partially longitudinally sectioned, a 10 safety device 10 in combination with the associated triggering mechanism 12 which is provided for triggering a switching function at a specific hydrostatic pressure. The triggering mechanism 12 is described in detail in the older Patent Application P 40 14 826.2, so that it is not 15 necessary to go hereinto once acaJn. n connecti-en with he safety device 'LO, with respect to the triggering mechanism 12 reference is made zo the drive mechanism 14 thereof, which is designed, for example, with. a spring mechanism and a toothing 16. A coupling toothed wheel 22 20 which meshes with the toothing 1.6 of the drive mechanism 14 projects away from a cap- shaped element 18 which is mounted so as to be rotatable about a central axis 20 of the safety device or respectively triggering mechanism 10; 12. In the axial direction of the central axis 20 and 22 there is transmission means of a the central 30 of a time offset against the coupling toothed wheel provided, the coupling toothed wheel 22, a toothed wheel 24 which is connected by connection axis 26, orientated parallel to axis 20, with a pinion 28. A toothed wheel 8 delay mechanism 32 meshes with the p n on 28, the toothed wheel 30 being mounted so as to be rotatable about the central axis 20. The toothed wheel 30 of the time delay mechanism 32 is illustrated in FIGURE 2 in a top view. From this Figure it is also evident that the toothed wheel 30 has an arcuate free-motion recess 34, the one end 1 portion of which forms an end stop 36 for the actuation of a second safety switch 38. Th e second safety switch 38 is also clearly evident from FIGURE 3. It has a fixed switch part 40 and a switching member 42 which is movable with respect to the fixed switch part 40. A switching pin 44, which extends into the arcuate recess 34 of the toothed wheel 30 of the time delay mechanism 32, stands away from the movable switching member 42. A switching actuation, i.e. an adjustment of the second safety switch 38 from the passive switching position shown in FIGURE 2 into the active switching position, is effected as soon as the toothed wheel 30 is driven in the anticlockwise direction, i.e. in the direction of the arrow 46, and the end stop 36 of the arcuate recess 34 butts against the switching pin 44 of the second safety switch 38. A further rotation of the toothed wheel 30 in the anticlockwise direction then results in a switching movement, i.e. a switch-over of the second safety switch 38 from the inactive into the active switching position. Driving of the toothed wheel 30 in the opposite clock-hand (anticlockwise) direction will be described later on.

A first safety switch 48 which cooperates by means of i 1 1 i i i 1 1 9 a slider element 50 with a force element 52, can also be perceived from FIGURE 1. The force element 52 it is a matter, for example, of a pyrotechnical force element.

The first safety switch 48 with the slider element 50 and the force element 52 is also clearly evident from FIGURES 4a and 4b. The first safety switch 48 has, like the second safety switch 38 (see FIGURES 2 and 3), a fixed switch part 40 and a movable switching member 42. The slider element 50 is guide linearly along a guide mechanism 54 or respectively held fast by means of a shear pin 56 (see FIGURE 4a) in the inactive switching position of the first safety switch 48 or respectively of the force element 52. The slider element 50 is designed with a central hole 58 as well as with a slider nose 60 and a slider extension 622.

As is evident from FIGURE 11,the cap-shaped element 18 from which the coupling toothed wheel 22 stands away has a recess 64, into which the slider nose 60 extends in the inactive operating position of the force element 52, as shown in FIGURE 1, so that in this operating position the cap-shaped element 18 and, thus, the coupling toothed wheel 22 are prevented from rotating about the central axis 20. At the same time the toothed wheel 30 of the time delay mechanism 32 in the inactive operating position is also prevented from rotating about the central axis 20, because the slider extension 62 standing away from the slider element 50 extends into a recess 66 provided in the toothed wheel 30 of the time delay mechanism 32.

It is also evident from FIGURE 1 that a spring 68, which in this embodiment is a torsion spring, is secured with its one end portion 70 to the time delay mechanism 32 and with its second end portion 72 to a housing 74 of the 5 triggering mechanism and safety device 12; 10.

1 FIGURE 5 shows in a three-dimensional representation the fixed switch part 40 and the movable switching member 42 of the first safety switch 48, in which respect 10 connection elements stand away from the fixed switch part 40, as is also evident from FIGURE 6. The connection elements 76 and 78 are connected in an electrically conductive manner to contact pins 80 or respectively 82. In FIGURE 6 the fixed switch part 40 is shown with its two component parts spatially separated, in order to make clear the contact bushes 84 that are to be contacted with the contact pins 80 or respectively 82, which are connected electrically to contact bridges 86 or 88 bridges 86 and 88 are also 7.

respectively. The contact 20 clearly evident from FIGURE The mode of operation of the safety conjunction with the triggering mechanism provided in the common housing 74, will hereinunder. The devices 10,12 are situated, on the underside of a launching tube in an space provided for this purpose and have ensuring the storage, transportation as well safety of a sea mine. The safety device 1LO device 10 in 12, which are be described for example, installation the task of as handling is designed 1 1 1 i 1 1 i j i 1 1 - J 1 i t i f 1 1 1 with the two mechanical safety switches 48, 38 which are independent of one another, which galvanically interrupt the supply of energy to the the arming of the mine. The way of the slider element 50 one shear pin 56 in its closed by the force element in this respect ignited e.g. suitable control unit of the sea mine ignited. The on- board impulse is illustrated diagrammatically in FIGURE 8 by the arrow 90. The block 92 is intended to represent the ignition of the force element. The block 94 subordinated to the block 92 is intended to illustrate the shifting of the slider element 50, whereby the triggering mechanism 12 is activated. This is indicated by the block 96 which is subordinated to the block 94 and which represents the operating state of the unlocked water pressure sensor, in which the cap-shaped element 18 is movable in the direction of the central axis 20, so that the coupling toothed wheel 22 comes into meshing engagement with the transmission toothed wheel 24 when, with the aid of the water pressure sensor or respectively the triggering mechanism 12, an appropriate hydrostatic pressure is indicated in FIGURE 8 by the block 98 and the mechanical coupling, i.e. the meshing engagement of the coupling toothed wheel 22 into the transmission toothed wheel 24, is indicated in FIGURE 8 by the block 100.

detonation electronics until first safety switch 48 is, by which is held by the at least inactive operating position, 51. The force element 52 is by an on-board impulse from a If, upon the ignition of the force element 52 (block - 0 12 9.2 in FIGURE 8), the slide element 50 is moved as described above linearly along the guide mechanism 54 (see FIGURES 4a and 4b), then the first safety switch 48 is closed, which is indicated in FIGURE 8 by the block 102.

5- At the same time in this respect the toothed wheel 30 of the time delay mechanism 32 is released, which is illustrated in FIGURE 8 by the block 104, because the slider extension 62 is moved out of the recess 66 (see FIGURE 1). Since, upon the said linear motion of the slider element 50, the slider nose 60 is moved out of the recess 64 in the cap-shaped element 18, the cap-shaped element 18 can not only carry out the above-mentioned linear movement in the axial direction of the central axis 20, but, driven by the drive mechanism 14 also carry out a rotary motion about the central axis 20, which means that the drive mechanism 14 can be started up. This is indicated in FIGURE 8 by the block 106. The block 108 subordinated to the block 106 is intended to indicate the run-down of the drive mechanism 14, which may, for example, be a spring-box, in which a biased torsion spring and a clock- work with pallet wheel, pallet and balancewheel for the time control is situated.

1 In the meshing connection between the coupling toothed wheel 22 and the transmission toothed wheel 24 is established, then, by means of the drive mechanism 14, by way of the connection axis 26 the pinion 28, and by way of the pinion 28 the toothed wheel 30 of the time delay mechanism 32, is driven in the direction of the arrow 46 13 (see FIGURE 2), so that it is possible, with the aid of the end stop 36, - as has already been mentioned earlier - to actuate the second safety switch 38, i.e. to close same, which is illustrated in FIGURE 8 by the block 110.

The second safety switch 38 is, thus, closed upon the run down of the time delay mechanism 32 forming a mechanical arming delay unit. The spring 68 (see FIGURE 1) provided between the toothed wheel 30 and the housing 74 acts contrary to the direction of rotation, brought about by the drive mechanism 14, of the toothed wheel 30 of the time delay mechanism 32 and thus prevents after a release, occasioned for example by vibration, of the toothed wheel by the slider element 50, an undesired rotary motion in the run-down direction, i.e. in the direction of the arrow 46 in accordance with FIGURE 2.

The safety switches 38 and 48 in each case have two pairs of contacts, which in each case cooperate with contact bridges 86 or 88 respectively. if the respective movable switching member 42 is moved as described above, then the pairs of contacts are closed by way of the contact bridges 86 or 88 respectively. In this respect, by way of the first pair of contacts the first part of an energy supply lead (not shown) is closed. The second pair of contacts is designed as a testing contact for the external checking of the switch position. In this respect, the second pair of contacts of the first safety switch 48 is connected directly to a fuse checking plug.

Correspondingly the first pair of contacts of the second 14 safety switch 38 closes an energy supply lead (not shown), whilst the second pair of contacts of the second safety switch 38 is, for example, intended to close a signal lead for triggering the charging-up of an ignition or detonation circuit. If both safety switches 38 and 48 are closed, the sea mine is armed.

1 AS emerges from what has been said above in conjunction with the Figures of the drawings, in which identical parts are in each case designated with the same reference numbers, a restoring function is effected by the spring 68. If during the function cycle of'the triggering mechanism and safety device the coupling toothed wheel 22 is brought out of engagement from the transmission toothed wheel 24, the spring 68 can rotate the toothed wheel 30, carrying out a switching function, of the time delay mechanism 32 back into its starting or respectively original position, so that the running time of the drive mechanism 12 is no longer sufficient to carry out the switching function. Moreover, no switching function arises if the specific hydrostatic pressure does not exist of the triggering mechanism 12 during the entire running time of the drive mechanism 14. If the existing hydrostatic pressure falls below the specific hydrostatic pressure, the drive mechanism 14 continues to run independently thereof Upon renewal of the hydrostatic pressure the drive mechanism 12 has, however, already run down to such an extent that the switching function can likewise no longer be carried out.

1 1 1 1 1 1 i 1 1 Upon faulty delivery of a correspondingly equipped underwater mine more especially two possibilities are to be considered, namely 1. Reaching of a water depth, corresponding to a specific hydrostatic pressure, without triggering of the on-board impulse for the activation, i.e. ignition, of the force element 52, or 2. Reaching of the minimum depth of water, corresponding to a specific hydrostatic pressure, delayed after the activation of the force element 52.

The firstly mentioned variant of a for example, afforded if the is, fl unintentionallv into the water without 52 having been ignited by the on-board defective delivery sea mine drops the force element impulse. In this case the triggering mechanism 12, i.e. the cap-shaped element 18, is prevented by the slider element 50 from an axial release movement and no arming takes place.

If the force element 52 ignites after entry into the water as a result of any event whatsoever, this can lead to an arming of the sea mine lead only if, in addition, a mine battery is active and if at the same time the force element 52 ignites still prior to a pressure equalisation of the triggering mechanism 12, so that the hydrostatic minimum pressure still over the necessary running time of the time delay mechanism 32 holds the coupling toothed 16 wheel 22 in meshing engagement with the transmission toothed wheel 24. If the force element 52 only ignites later, the hydrostatic pressure has equalised through the at least one compensation aperture described in the 5 repeatedly mentioned older Patent Application P 40 14 826.2, whereby the coupling toothed wheel 22 is then no 1 longer in meshing engagement with the transmission toothed wheel 24.

L5 In the case of the second variant of a defective delivery, i.e. of a reaching of the minimum depth of water delayed after the ignition of the force element 52 the f ollowing applies: As has been been stated, the slider element 50 upon the ignitJ ng of the -force element 52 releases the rotary motion of the coupling toothed wheel abcut the central axis, so that the time delay mechanism 32 starts immediately, i. e. starts up. If the sea mine fails in a temporally delayed manner - 'nto "',.-he water and reaches its minimum depth of water corresponding to a specific hydrostatic pressure, the time delay mechanism 32 has already run down to such an extent that the rotary path of the toothed wheel 30 or respectively of the arcuate recess 34 is no longer sufficient to close the second safety switch 38.

1 i 1 1 i i 1 1 i i 1 17

Claims

1. A safety device for a triggering mechanism (for triggering a switching function at a specific hydrostatic pressure), which has a drive mechanism with a toothing, a coupling toothed wheel which is displaceable between a passive operating position and an active operating position and in each operating position meshes with the toothing of the drive mechanism, and a transmission toothed wheel which, upon appropriate pressure impingement on the triggering mechanism unti-l the pressure equalisatIon, is in meshing engagement with the coupling toothed wheel, characterised in that two safety switches which are independent of one another and which are in each case displaceable between a passive position and an active position are provided, In that a --orc:e element is provided for the actuation of the first safety switch, in that the second safety switch is provided on a time delay mechanism which is connected to the triggering mechanism, and in that the first safety switch is provided for the locking or respectively releasing of the triggering mechanism and of the time delay mechanism.

2. A safety device according to Claim 1, characterised in that the first safety switch has a slider element which is associated with the force element and which is guided linearly along a guide mechanism or is respectively secured by means of a shear pin on the guide mechanism, and in that the guide mechanism is provided with at least j 18 one end stop f or the slider element, against which the slider element butts, with the f orce element activated, for the securing of the first safety switch in the active operating position.

3. A saf ety device according in that the slider element has extension, in which respect in force element, the slider torsionally-fast restraining of and the slider extension serves time delay mechanism.

to Claim 2,, characterised a slider nose and a slider an inactive position of the nose services for the the coupling toothed wheel for the restraining of the

4. A saf ety device according to Claim 3, characterised 1.5 in that the time delay mechanism has a toothed wheel with a recess, in which in the inactive operating posi tion the slider extension is disposed for the torsionally-fast restraining of the toothed wheel, and in that the toothed wheel of the time delay mechanism is provided with an end stop for the actuation of the second safety switch.

5. A saf ety device according to Claim 4, characteristic in that a spring is secured with its one end portion on the toothed wheel of the time delay mechanism, the second end portion thereof being arranged fixedly on the housing of the safety device, in which respect the spring preloads the toothed wheel of the time delay mechanism in a direction of rotation which is opposite to the direction of rotation in which the toothed wheel of the time delay 1 i i 1 1 1 1 1 1 1 3 19 mechanism is driven by the drive mechanism by way of the coupling wheel and the transmission wheel in the appropriate operating position.

6. A safety device according to Claim 4, characterised in that the toothed wheel of the time delay mechanism has an arcuate f ree-motion recess which is provided with the end stop provided f or the actuation of the second saf ety switch, and in that the second safety switch has a switching pin which projects into the arcuate free-motion recess.

7. A safety device according to any one of the preceding claims, characterised in that each of the two safety is switches has a f ixed switch par t and which is movable with respect to the in which respect each switch part contacts and each switching member bridges.

a switching member fixed switch part, has two pairs of has two contact

8. A safety device substantially as hereinbefore described, with reference to the accompanying drawings.

9. A triggering mechanism incorporating a safety device as claimed in any preceding claim.

10. A triggering mechanism arranged to operate substantially as hereinbefore described with reference to FIGURE 8 of the accompanying drawings.

11. A sea mine incorporating a triggering mechanism as described in Claim 9 or 10.

Published 1992 at The Patent Office. Concept House, Cardiff Road. Newport. Gwent NP9 I RH. Further copies may be obtained from Sales Branch. Unit 6, Nine Mile Point. Cwnifelinfach. Cross Keys, Newport. NP I 7HZ. Printed by Multiplex techniques lid. St Mary Cray, Kent.

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