Kelley Company, Inc.

Douglas Dynamics LLC

David E Bennett

Joseph R Driear

Jack C Hill

A device for locking a vehicle to a loading dock during a loading operation. The device includes a frame mounted on the front surface of the dock beneath a pit which houses an adjustable dockboard. A slide assembly is mounted for vertical movement on the frame, and the slide assembly includes a locking member adapted to engage an abutment on the vehicle, as the slide assembly is elevated. To raise and lower the slide assembly, a motor is mounted on the slide assembly and drives a gear that engages a rack carried by the frame. The rack is spring biased to an upper position, and on operation of the motor in one direction, the slide assembly is raised to bring the locking member into engagement with the abutment on the vehicle. Continued operation of the motor will then move the rack downwardly relative to the gear and slide assembly, and downward movement of the rack will activate a switch to cut off power to the motor. After the loading operation is completed the motor is driven in the opposite direction to lower the locking member to its storage position. The movement of the slide assembly and locking member can be tied into the operation of the lip of the dockboard in which the motor will automatically be operated to move the locking member upwardly toward the locking position when the lip is raised from its pendant position, and the motor will be operated in the reverse direction when the loading operation is completed and the lip is returned to its pendant position.

Truck locking device

A hydraulically operated dockboard comprising a ramp which is hinged at its rear edge to the frame of the dockboard, and a lip is hinged to the forward edge of the ramp and can be pivoted between a downwardly hanging pendant position and an extended position. A main hydraulic cylinder unit interconnects the frame and the ramp, and by operating the cylinder unit the ramp can be pivoted upwardly from a horizontal cross traffic position to an upwardly inclined position. As the ramp approaches its fully raised position, hydraulic fluid is conducted from the main cylinder unit to a lip lifting cylinder which interconnects the ramp and the lip. Introducing fluid to the lip lifting cylinder will act to pivot the lip to the extended position. When operation of the main hydraulic unit is discontinued, the combined weight of the ramp and the lip will cause the ramp to descend, and when the ramp descends to a predetermined position, the hydraulic fluid will return from the lip lifting cylinder to the main cylinder unit to thereby permit the lip to pivot by gravity to the pendant position.

Hydraulically operated dockboard

A safety leg construction for a dockboard which acts to limit normal slow descent of the ramp, as well as rapid descent of the ramp, after a truck pulls away from the loading dock. Legs are hinged to the undersurface of the forward edge of the ramp and are biased to a forward supporting position and can be pivoted to a retracted non-supporting position. The legs are coupled to the lip of the dockboard by a coupling member which is pivoted to the leg and has an abutment positioned to be engaged by a cam attached to the lip as the lip is extended to thereby move the coupling member and the leg to the retracted position. An acceleration responsive latching element serves to lock the coupling member to the leg so under normal operation they move as a unit. Under a rapid gravitational descent of the ramp, caused by an added load on the ramp when the truck pulls away from the dock, the increased acceleration of the ramp will actuate the latching element to release the coupling member from the leg and enable the biasing means to return the leg to the supporting position, independent of the position of the lip and coupling member, to thereby support the ramp against further descent.

Safety leg construction for a dockboard

A control lever extends through a cruciform opening in a control box and inside of the box fixed electrical contacts surround its inner end in an array corresponding to the shape of the cruciform opening. A common electrical contact is connected to the lever. Selective movement of the lever into the guideways provided by the cruciform opening selectively completes electrical contact of the common contact with the fixed electrical contacts to energize a desired electrical circuit. The lever is spring biased so that, when the operating force is removed, the lever returns to a neutral position out of engagement with all fixed contacts. A solenoid is selectively engageable with the lever to restrict movement thereof from the neutral position.

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Waukesha, WI, United States of America

David E Bennett