GB689788A - - Google Patents

Abstract

689,788. Pneumatic single-stroke apparatus. GEWERKSCHAFT EISENHUTTE WEST - FALIA. May 1, 1950 [June 4, 1949], No. 10711/50. Class 8 (ii) [Also in Groups XXIX and XXX] Auxiliary means for displacing a conveyer during the extraction of coal by using pneumatic or hydraulic piston and cylinder actuators is characterized by the supply of fluid pressure being through separate passages in the piston rod communicating with front and rear sides of the piston, such passages having short connecting links at the remote end of the piston rod coupled with a pressure medium supply line ranged alongside the conveyer. Each cylinder 12 is adapted to be sustained by a cable 13 connected to two pit props 14. The piston rod 15 is connected at its free end at 16 to the conveyer 11, a boss 15k on the rod 15 engaging a bracket 10a on the conveyer in which it is retained by a collar 15n. The rod 15 consists of two concentric tubes 15a, 15b. Fluid flows through the central tube 15b to reach the rear 12a of the piston 15c for pushing the conveyer towards the coal face 10, and through the annular space 15h and an outlet 15i to act on the front of the piston 15c to retract the cylinder towards the conveyer, the free end of the rod 15 having a head 15f provided with separate inlet connections 15d, 15g for the passages 15b, 15h respectively. After retraction of the cylinder following the pushing movement, the points of attachment of cable 13 are brought further forward in readiness for the next pushing stroke.