Abstract: A concrete pump with a pivoting valve and hopper assembly is provided with a novel wear plate and wear ring. The wear plate is mounted on the frame of the pump and remains mounted on the frame as the valve and hopper assembly pivots between open and closed positions. When the valve and hopper assembly is open, the wear plate is accessible for examination and replacement. The hopper is provided with an opening through which the wear plate extends when the valve and hopper assembly is closed. A seal on the hopper around the opening sealingly engages the frame. A wear ring on the valve engages the wear plate when the valve and hopper assembly is closed. A cam plate on each side of the frame is engageable with the valve and hopper assembly as the assembly pivots to a closed position to ensure alignment between the valve and hopper assembly and the frame.

Abstract: A concrete pump includes a hopper having a plate with a pair of openings and an S-tube valve assembly which is movable between the two openings. The valve assembly includes an S-tube which is connected to a mounting plate which is pivotally mounted on the hopper. A wear ring is movably supported within an opening in the valve assembly and engages the hopper plate. A retainer ring is positioned within the opening of the valve assembly and engages a flange on the valve assembly. A resilient spring is positioned between the wear ring and the retainer ring and resiliently urges the wear ring against the hopper plate.

Abstract: A concrete pump includes a hopper having a plate with a pair of openings and an S-tube valve assembly which is movable between the two openings. The valve assembly includes an S-tube which is connected to a mounting plate which is pivotally mounted on the hopper. A wear ring is movably supported within an opening in the valve assembly and engages the hopper plate. A retainer ring is positioned within the opening of the valve assembly and engages a flange on the valve assembly. A resilient spring is positioned between the wear ring and the retainer ring and resiliently urges the wear ring against the hopper plate.

Abstract: The hopper of a concrete pump is pivotally mounted on the frame of the pump so that the hopper can be swung away from the pumping cylinders in order to clean the S-valve in the hopper. O-rings on the frame surround the pumping cylinders and sealingly engage the hopper when the hopper is closed against the pumping cylinders.

Abstract: A pilot assembly for switching the fluid supply valve of a hydraulic pump is actuated by the pressurized hydraulic fluid which operates the hydraulic pump. The hydraulic pump includes a main cylinder, a main piston within the main cylinder, and a main valve for supplying pressurized hydraulic fluid to the rear end of the main cylinder for driving the piston forwardly. The pilot assembly includes a pilot cylinder and a pilot spool within the cylinder. A first hydraulic conduit connects one end of the pilot cylinder to the front end of the main cylinder, and a second hydraulic conduit connects the other end of the pilot cylinder to the main cylinder at a position spaced rearwardly from the front end of the main cylinder. When the main piston passes forwardly of the second hydraulic conduit, the pressurized hydraulic fluid in the main cylinder moves the pilot spool, and pressurized hydraulic fluid is allowed to flow to the main valve to switch the main valve.