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Ro-30 pressure fuze, Czechaslovakia

pzgr40

Well-Known Member
Premium Member
Cutaway model of a Czech Ro-30 pressure fuze. The R0-30 has to be pressed upon up til 30 times to make it function, making it an ideal fuze for usage against rail targets (trains).
The fuze is placed under the rails either under rail sleepers, and connected to an explosive charge.
One has to take into account however that most wagons have two wheel sets, so the maximum train length before exploding is 15 wagons.
The fuze can also be set for fewer depressions by pressing in the fuze by hand a number of times by the formula ; desired depressions = 30 – times depressed.

The fuze is 160mm high, 160mm long and has a width of 68mm. The fuze was used in the 1950-1970 period, but could well be still in use.

The fuze consists of a cast zamac body through which a firing pin mechanism is placed horizontally. The pressure pin is placed vertically and consists a pin with a mushroom shaped top, screwed into the lower part of the pressure pin mechanism. Over the lower part of the pressure pin a brass piston (picture 03)is placed with two small plates (the escapement) that fit in the pins of the pinwheel, one plate in lower position , one plate in upper position. Under the pressure pin a spring is placed that pushes the pressure pin upward every time it is depressed.
The horizontally placed spring loaded firing pin housing has a tooth rack at the backside. The spring loaded firing pin in the firing pin housing is kept in backward position by two steel balls placed in a groove in the collar of the firing pin. The spring behind the firing pin housing wants to move the firing pin housing forward up to a momment where the toothrack at the backside of the firing pin housing expires. The gearwheel behind the toothrack consists of a small gearwheel with a pinwheel connected to the top (picture 03). The gearwheel runs over the toothrack of the firing pin housing, prevented form rotation by the escapement on the pinwheel. By depressing the vertical pressure pin and the return movement by the spring below the pressure pin, each time one pin of the pinwheel is released, rotating the gearwheel in the toothrack, untill the moment the toothrack expires after 30 depressions. This releases the firing pin housing, allowing the balls retaining the firing pin to fall in two holes, releasing the firing pin, exploding the firing cap, which explodes the main charge.

Of course one will understand this fuze is ideally suited for sabotage actions.

Regards, DJH.
 

Attachments

  • 01 - RO-30 front view.jpg
    01 - RO-30 front view.jpg
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  • 02 - RO-30 sideview.jpg
    02 - RO-30 sideview.jpg
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  • 03 - RO-30 escapement counting mechanism.jpg
    03 - RO-30 escapement counting mechanism.jpg
    286.8 KB · Views: 46
  • 04 - Ro-30 under rail.JPG
    04 - Ro-30 under rail.JPG
    75.8 KB · Views: 36
  • 05 - Ro-30 under sleeper.JPG
    05 - Ro-30 under sleeper.JPG
    63.3 KB · Views: 36
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