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Light- and sound signal DM57 with a lever activated fuze DM1474

pzgr40

Well-Known Member
Premium Member
Cutaway model of a light- and sound signal DM57 with a lever activated fuze DM1474. The light- and sound signal is meant to prevent enemy personel from approaching friendly positions unnoticed.
The light- and sound signal DM57 is being delivered in a cartboard box (pict.03) together with a mounting strip, two nails, a spool with thin steel (trip)wire, and two cartboard spools with cord.
The light- and sound signal DM57 can be mounted to a three, a three branch , a wooden pole or a door post with the two nails. Than, the light- and sound signal is placed in the hole of the horizontal part of the strip with the threaded bushing at the base, over which the fuze DM 1474 is screwed. After that, the trip wire is locked between the lock up nut and a lock up plate (picture 2).

The light- and sound signal DM57 consists of an aluminium pipe with a base flange. A threaded bushing containing the firing cap is integrated with the base flange. On the inside of the aluminium pipe, an aluminium cup containing the flare composition is placed. The flare cup is 2,5 mm smaller in diameter than the inside of the pipe. A pressed in groove at the base of the flare cup allows the flame of the firing cup to move upward along the inside of the pipe and reach the disc of pressed black powder, placed between the flare and the sound signal. If this disc is ignited, the flare is ignited, as well as the pyrotechnic element of the sound signal. The pressure build up in the pipe launches the sound signal 15 mtrs. up in the air where it explodes with 165 Db. The flare emits a bright yellow light for 15 seconds.
The order of parts in the flare -top to bottom- is ; Brown plastic protection cap, white silicon rubber disc, hard plastic disc, locking ring for bore, aluminium disc, white silicon rubber disc, sound signal, plastic ring with small hole, waved steel distance ring, plastic ring with big hole, black powder disc, flare, firing cap.

Functioning of the lever fuze DM 1474 (see PDF drawing 04 - DM1474):
The lever fuze DM1474 has a spring loaded firing pin which is kept in place by two balls which fall into the groove of a bushing surrounding the firing pin. A locking pin which is tapered on two sides (yellow) keeps the balls fixated in the outside position, locking the firing pin in the springloaded position. This locking pin is fixated in the afterward position by a U shaped safety pin that fixates the firing pin as well as the locking pin (Safe).
The Fuze DM1474 is safe as long as the U shaped safety pin is in the closed position; one leg of the U through the firing pin, the other leg -which is threaded- has a bakelite locking nut which is tightened in the safe position (as in picture 02). On both sides of the U a cord can be knit, so the light- and sound signal can be set to safe or armed from a safe distance (armed).
At the base of the fuze a flanged and threaded lever pin is placed (purple) to which the tripwire is connedted. Above the lever pin a flanged push pin is placed (blue). If one pulls the tripwire, the lever pin (purple) rotates , and the push pin (blue) is pushed upward by the flange of the lever pin. This pushed the locking pin (yellow) upward untill the balls can move inward over the tapered ends of the locking pin (activated), allowing the firing pin to move into the firing cap (fired).

Length light- and soundsignal DM 57 with lever fuze DM1474 : 154 mm
Length fuze DM 1474 : 88 mm
Length light and soundsignal DM57 : 71 mm
Diameter light and sound signal DM57 (aluminium pipe) : 26,5 mm

Regards, DJH
 

Attachments

  • 01 - Signal Illuminating and sound DM 57 with fuze 1474.jpg
    01 - Signal Illuminating and sound DM 57 with fuze 1474.jpg
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  • 02 -  Signal Illuminating and sound DM 57 with fuze 1474 placed.jpg
    02 - Signal Illuminating and sound DM 57 with fuze 1474 placed.jpg
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  • 03-  Signal Illuminating and sound DM 57 box.jpg
    03- Signal Illuminating and sound DM 57 box.jpg
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  • 04 - tekening DM 1474.pdf
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Thank you again DJH for this interesting piece of beautiful work. https://depatisnet.dpma.de/DepatisN...romHitlist=1&NrFaxPages=7&pdfpage=1&xxxfull=1 Here is the patent for the igniter. The signal is on the market already much longer than the igniter. Many countries (denmark, Sweden, Norway a.o.) were using it already 30 years ago, but with an older model igniter. See the attached foto from a danish site. Does anybody here know which company/manufacturer uses CA as shorthand for his name in the lot-No. ?
Regards,
Bellifortis.
 

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  • Mine_Alarmmine_M87.jpg
    Mine_Alarmmine_M87.jpg
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