Lifting and dumping apparatus

Claim 1

A lifting and dumping apparatus for dumping the contents of a container into the body of a vehicle including: a pair of lift arms pivotally secured to the vehicle for movement between a lower position in which the front portions of the lift arms extend forward of the vehicle and an upper position in which the front portions of the lift arms extend above the vehicle; lift arm power means to move the lift arms between their lower and upper positions; a front cross member extending between and rotatably supported by the front portions of the lift arms; a pair of fork arms for engaging the container; attaching means to secure the fork arms to the front cross member, and including two pins extending from the front cross member wherein the pins are generally vertical when the fork arms engage the container, two bracket plates wherein each bracket plate is pivotally supported by a pin and each fork arm is secured to a bracket plate for pivotal movement therewith between an open position and a closed position, wherein the fork arms extend forward of the lift arms for engagement with the container, and a closed position, wherein the fork arms are generally parallel to the front cross member, and spacing members mounted on the front cross member and extending between the front cross member and the bracket plates to prevent the bracket plates from sliding along the axes of the pins and to support the bracket plates for pivotal movement thereabout, and wherein back ends of the fork arms define notches for receiving the front cross member as the fork arms move into the open position wherein the front cross member supports the fork arms when the fork arms are in the open position; dumping means connected to the lift arms and the front cross member for rotating the front cross member, and pivoting the fork arms about the axis of the front cross member; and fork arm power means to pivot the fork arms between their open and closed positions, and including a pair of hydraulic cylinders, each having a movable piston rod connected to one of the bracket plates to pivot the fork arms between their open and closed positions, and a hydraulic fluid circuit connected to the hydraulic cylinders to move the piston rods thereof, and including sequencing means to alternately pivot the fork arms from their open position to their closed position.