Dock leveler assembly with adjustable automatic release

Abstract

A dock leveler assembly includes a base and a ramp that is pivotably movable under the influence of a biasing arrangement to a raised position. The ramp is lowered into engagement with a truck bed, preferably via a lip connected to the outer end of the ramp, and a holddown assembly maintains the ramp in a lowered position during loading and unloading of the truck bed against the force of a biasing arrangement that urges the ramp toward a raised position. The holddown assembly includes an extendible and retractable mechanism which is selectively fixed in position to maintain the ramp in a desired position. A 'float' apparatus using a compression spring accommodates a certain amount of vertical movement of the ramp as the truck bed moves up and down during loading and unloading. A release arrangement enables the holddown assembly to be extended and retracted, and includes an automatic actuating arrangement that allows the mechanism to be extended upon application of a selected upward force to the ramp when the ramp is in a lowered position. The automatic actuating arrangement includes a flexible member such as a chain, and an adjustment arrangement for adjusting the inoperative position of the release member so as to control the degree of movement of the release member that is required in order to move the release member to the operative position from the inoperative position. The adjustment arrangement may be in the form of a threaded connection between one end of the actuating member and the release member, for selectively varying the inoperative position of the release member. The purpose of the adjustment is to control the amount of upward force that is required to actuate the release member, in order to avoid premature release and to avoid damage that can occur if the release does not occur until after an excessive upward force is applied.