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Fold-Up Rear Truck Bumpers
Thomas Wagner, Fisher, Minn., and Bill Olson, Alvarado, Minn., built "fold-up" rear truck bumpers that comply with new state laws requiring rear truck bumpers and yet fold out of the way so the box can be dumped normally. The primary purpose of the bumpers is to prevent a vehicle from sliding under the truck box frame during a rear end collision.
Wagner made his bumper from 1 1/2-in. dia. double strength pipe. The rear section is 5 ft. wide and has two 24-in. lengths welded to it to fit the frame width.
Wagner welded a short length of 2 1/2-in. dia. pipe across the end of each arm. The 2 1/2-in. dia. pipe fits over a smaller diameter pipe that's welded to a flat iron bolted to the truck box frame. This provides a hinge to allow movement up or down.
Wagner welded two short chains to the bumper and truck box frame to hold the bumper at the required 30-in. height. He attached a 5/16-in. cable to one side of the bumper. It's threaded through two pulleys and the end of the cable is attached to
the main truck frame. As the hoist is raised, the cables pull the truck bumper up and out of the way for unloading.
Contact: FARM SHOW Followup, Thomas Wagner, Fisher, Minn. 56723 (ph 218 281-2035).
Olson's bumper (pictured) is made from channel iron and hinged at the truck frame. Olson made the hinge from a 1/4-in. plate and welded it to the frame which he drilled to receive the 1-in. shaft as a pivot. Welded to the shaft are two 2 by 3/4-in. flat irons long enough to keep the channel iron bumper at the height required by law. Stops welded to the hinge plate keep the bumper assembly from moving. Olson built brackets to accept a single action cylinder which is plumbed into the hydraulic system of the truck. He uses a flow control valve to limit oil flow to the bumper lift cylinder.
As hydraulic pressure is applied to the system, the bumper cylinder, which re-quires less pressure to activate than the box lift cylinder, is activated first, pushing the bumper back and up against the
truck box floor before the box is lifted. The reverse is also true. As the box drops, the bumper remains in the lifted position until the box is down and the return spring on the bumper lift cylinder returns it to the closed position, returning
the bumper to the lowered position. Olson says the total cost of materials was $125 to $150.
Contact: FARM SHOW Followup, Bill Olson, RR 1, Alvarado, Minn. 56710 (ph 218 965-4847).

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1989 - Volume #13, Issue #4