Hydraulic hoist for pickup bed

A method for converting a rigid bed truck having a passenger cab and hauling bed supported on a frame to a tilting bed truck where the truck bed may be tilted between an upright and horizontal configuration such that the relationship between the truck cab and bed when the bed is in the horizontal position is the same as prior to the conversion, comprising:

• removing the truck bed from the frame,
• attaching two longitudinal members at spaced relationships to the underside rearward end of the truck bed,
• attaching a first plate member having an aperture therein to each longitudinal member, said plate member extending outwardly from the bottom to the truck bed,
• mounting two second plate members having an aperture therein to the rearward end of the truck frame such that the apertures in said second palte members are aligned with the apertures in said first plate member,
• inserting a pin through the apertures of said first and second plate members to permit relative rotation between said first plate members and said second plate members thereby effectuating a hinge between the truck bed and frame,
• mounting a support frame on the underside of the truck bed at its forward end,
• rotatably attaching a first arm to the frame such that the arm extends forwardly from the frame,
• rotatably attaching a second arm to the support frame on the underside of the truck bed such that the second arm extends forwardly from the truck bed,
• interconnecting the extended ends of the first and second arms by a third arm,
• connecting a hydraulic ram between the first and second arms such that by varying the length of the hydraulic ram the second arm moves substantially longitudinally against the truck bed to tilt the bed.

An attachment for converting a fixed bed truck with a passenger cab and hauling bed supported on a frame to a tilting bed truck where the hauling bed may be rotated from a horizontal to a tilt position, such attachment permitting the passenger cab and hauling bed, when the bed is in the horizontal position, to assume the same relative position as before the conversion, comprising:

• two hinge members fixedly attached between the rear underside of the hauling bed and the rear of the truck frame, each said hinge member including a longitudinal member fixedly attached to the underside of the truck bed, a first plate member having an aperture therein and rigidly attached to said longitudinal member, said first plate member extending perpendicularly from the bottom of the truck bed, a second plate member fixedly attached to the truck frame and having an aperture therein, the aperture in said second plate member being alignable with the aperture in said first plate member, and a pin member adapted for insertion through the apertures in said first and second plate members, said pin member being sized to permit relative rotation between said first plate member and said second plate member thereby permitting relative rotation between the hauling bed and frame,
• a rigid support rectangular frame affixed to the underside of said truck bed,
• channel members fixedly attached to said rigid frame, said channel members and said rectangular frame forming receptacles adjacent the underside of the hauling bed,
• spaced lever members each pivotally connected at one end to the forward portion of the frame and extending forwardly from the frame,
• a pair of spaced lever arms, each adapted with cylindrical ears at one end thereof for engagement in the receptacles formed by said channel members,
• a coupling member pivotally connected at opposite ends between said other ends of said lever members and lever arms,
• a variable length actuator arm interconnected between said lever members and said lever arms including a cylinder having one end connected to said lever members, a piston arm movable within said cylinder and having a portion extending therefrom and connected to said lever arms, and an orifice valve mounted on said cylinder for receiving fluid into said cylinder to extend said piston arm and thereby move said lever arms substantially longitudinally against the underside of the hauling bed to tilt the bed and for controlling the discharge of fluid from said cylinder to retract said piston arm and said lever arms to lower the truck bed, said valve preventing the sudden discharge of fluid from said cylinder thereby preventing sudden dropping of the truck bed.