Draft Gear

At the beginning of the coupler's development stood the request to use a maximum coupling speed of 15 km/h (9.3 mph) without damages at the coupling system. This means high energy absorption by the draft gears is necessary.

This request led to the development of new draft gear designs. At the beginning was the request for 110 mm spring-travelling and a 200 Mp (440 924 pounds) end-force. The energy - absorption should be 60 %, to reduce back-springing after coupling.

The OSShD - engineers tried to fulfill these requests by a hydraulic spring system. For this project an hydraulic spring for tools was available from engineering office ZEK Hydraulik Leipzig. By this several variants according above requests have been developed - the general characteristic was the low weight.

But other requests like low working temperature up to - 55 ° C (-67 F) and the use of a stabilizing arm-end led to the termination of this development. The lateral forces at the piston rod from the stabilizing arm-end resulted in leakages at the gaskets.

The further development was concentrated at the development of rings springs, which includes mechanical components only. After some development stages at the end the draft gear with ring springs fulfilled all requests of the railway companies.