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| U.S.N.B.D. - BRITISH LAND MINES AND FIRING DEVICES |
| FIRING DEVICES |
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DIAMETER |
(a) 0.65" |
BRITISH TRIP MECHANISM |
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(b) 1.5" |
A. NO. 4
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(c) 0.75" | |
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LENGTH |
(a) 6.2" (with primer) | |
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(b) 5" (with primer) | |
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(c) About 4" (with primer) | |
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PULL OR PRESSURE |
(OBSOLETE) |
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REQUIRED |
(a) | |
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(b) 4 or 12 lbs. | |
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(c) | |
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COLOR |
Unpainted steel. | |
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GENERAL: |
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These device, Trip Mechanisms No. 4, 5, and 6, are all obsolete and are inclined in this publication for interest and information only. It is not expected that they will be encountered in operational use. Special note should be taken not to confuse these Trip Mechanims with the British Switches No. 4, 5, and 6, which are in service use. Brief description of the device follows. |
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DESCRIPTION: |
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Trip Mechanism No. 4: This device is designed on the hair trigger principle and is in-tended to be actuated by very light pulls. It is so arranged that the pull can be taken in any direction, or a number of different trip wires can be attached to the actuating lever. With the safety clip removed, a pull on any trip wire attached to the trip lever will pivot the lever from the top of the retaining pin, which is then forced by its spring out of the striker block. The retaining balls are allowed to move inwards, releasing the stri-ker and firing the percussion cap, which in turn sets off the detonator and attached pri-mer. |
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Trip Mechanism No. 5: This mechanism can be used in any of three different ways, and is provided with a light and a heavy spring which can be used alternatively to create operating conditions of greater or less force. A setting stud is provided in "Z"-shaped groove. To obtain pressure operation, place the stud in the "Press" position of the groove. Depending on the spring used, a pressure of 4 or 12 lbs. will then cause the upper of the two holes in the outer case to come opposite the retaining ball, allowing the retaining ball to move outward and release the striker, firing the percussion cap, detonator and primer. Release operation is accomplished by placing the setting stud in the "Lift" position with a weight of more than 4 or 12 lbs., depending on the spring, pla-ced on the top plate. Removal of the weight will allow the spring to force the inner casing upward until the retaining ball comes opposite the lower of the two holes in the outer case. The ball then moves into this hole and releases the striker. The stud is pla-ced in the "Press" position for that a light pull on the wire will rotate the outer case un-til the stud is in the "Lift" position. Since there is no weight to restain the mechanism, the devcie will function immediately as for release operation, described above. A safety pin, intervening between the striker and the percussion cap, pireces the inner and outer casings. |
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Trip Mechanism No. 6: This is a very simple device designed to be operate by direct pull only. It consists of a spring loaded striker retained by the end of a special compo-sition wire. A pull on the trip wire will release the striker and fire the device. Each me-chanism is provided with two feet of this wire, wrapped around the body of the device when issued. If a longer trip wire is desired, a length of standard trip wire is spliced to the free end of the special wire. |
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