Control arrangement for hydraulic motor

A control arrangement, comprising

• a hydraulic motor;
• adjustable pressure medium supply means including a pump, a reverse valve, a container and having an outlet;
• an unblockable check valve having a control connection;
• means forming a plurality of chambers including a supply chamber connected with said outlet of said supply means, a motor chamber arranged adjacent to said supply chamber and connected with said check valve, a first return chamber releasable in said container, a control chamber for connection with said control connection of said check valve, and a second return chamber located adjacent to said control chamber and connected therewith, said first return chamber being arranged so that the pressure medium flows back from the motor to said container, said second return chamber being associated only with a control flow of said check valve and said supply means;
• means for connecting said control chamber with said control connection of said check valve,
• means for connecting said second return chamber with said control chamber;
• a control conduit extending from said reverse valve of said supply means and leading to said control chamber;
• a control slider displaceable relative to said chambers so that during raising of said control slider it controls the pressure medium from said supply means via said check valve to the motor and during lowering of said control slider it releases the same to said container, said control slider controlling the connection between said control chamber and said second return chamber;
• a first pressure controlling member arranged on said control slider in the region of said control chamber and said second return chamber so that in a lowered position of said control slider said first pressure controlling member is located between said control chamber and said second return chamber and blocks communication between said control chamber and said second return chamber around said control slider so that the pressure medium flows through said first pressure controlling member and produces a sufficiently high unblocking pressure for said check valve, said control slider in its raised position includes means the communication between said control chamber and said second return chamber both around said control slider and through said first pressure controlling member, and said control slider in a neutral position includes means allowing direct communication between said control chamber and said second return chamber;
• and
• a second pressure controlling member communicating said control chamber and said motor chamber and opening to the latter.