Abstract: A jaw crusher for crushing rocks combines a hydraulic adjustment of the bite with an air spring tensioning arrangement which maintains a desired tensile force even with variation of the bite. The air spring arrangement is reliable in the dirty environment and also has long life. The use of several air springs in combination with a pressure sensing arrangement adds a safety factor. The more consistent tensioning force allows adjustment of both the tensioning arrangement and the bite of the rock crusher during operation thereof.

Abstract: Hydraulic control system for controlling the movement of the movable jaw of a rock crusher between a first set position and a retracted position. The control system includes a double acting hydraulic ram having first and second ends mounted on the frame of the rock crusher and movable jaw respectively. A source of high pressure hydraulic fluid provided. A first fluid supply conduit communicates between the source of high pressure fluid and a first fluid chamber of the ram. A second fluid supply conduit communicates between the source of high pressure fluid and the second fluid chamber of the ram. A flow control device is provided in the first and second fluid supply conduits for simultaneously locking hydrulic fluid in the first and second fluid supply conduits to hold the extensible ram in a substantially rigid fixed length condition when in the set position during normal operation of the crusher.

Abstract: A fluid gear or like pulling device comprising a body having a through axial bore adapted to admit a shaft; opposed piston chambers extending radially of the bore; pistons in the piston chambers and having a free end adapted to enter into the through bore; apparatus for pressurizing the piston chambers with fluid to force the piston outwardly of their chamber and into the through bore; a press ram mounted in the body for movement axially thereof; and apparatus for moving the press ram axially of the body, the body is sleeve shaped and the piston chamber extend through the sleeve shaped body from outside to inside, the outer end of the piston chambers being formed by the inner side of a ring that extends around the outside of the body.

Abstract: A yieldable assembly for mounting the bearing block of a roller in a frame for reciprocal movement therein comprising a first piston, a cylinder for said first piston, a piston rod on said first piston and extending from said cylinder, a second piston free for movement in said cylinder independantly of said first piston, a first chamber in said cylinder partially defined by one end of said second piston, a second chamber in said cylinder partially defined by the other end of said second piston and one end of said first piston, a third chamber in said cylinder partially defined by the other end of said first piston, means for charging said first chamber with a fluid, means for selectively charging said second chamber with a fluid, means for selectively charging said third chamber with a fluid, said cylinder and said piston being connectible between the frame and the bearing block of a roller mounted therein to permit reciprocation of the bearing block in the frame as the first piston and cylinder reciprocate w