US 4,662,021 A · Dockboard with a tread plate lock mechanism

Abstract

An independent dockboard of the type adapted to be mounted in a pit in a loading dock, the dockboard including a main frame, a ramp pivotally mounted on the frame and including a tread plate assembly mounted for telescopic movement into and out of the ramp, the tread plate assembly including a tread plate mounted on a frame with a number of wheels for supporting the assembly for movement on the ramp, the tread plate assembly being pivoted about the axis of the wheels, a lift frame pivotally mounted on the main frame and operatively positioned to engage the ramp, a hydraulic piston and cylinder assembly operatively engaging the left frame and a second hydraulic piston and cylinder assembly operatively connected to move the tread plate assembly into and out of the ramp, and an over center toggle link assembly to lock the tread plate against the ramp.

Claims10

Dependent claims

A dockboard adapted to be mounted in a pit in a loading dock, said dockboard including

a main frame,
a ramp pivotally mounted on the frame,
means for pivoting said ramp with respect to said frame,
a tread plate assembly mounted in said ramp for linear movement between a storage position within said ramp and an operable position forming a continuation of said ramp,
means for moving said tread plate assembly between the operative and storage positions, and
means connected between said tread plate assembly and said moving means for locking said tread plate in the operative position.

3 more elements

A dockboard adapted to be mounted in a pit in a loading dock, said dockboard including

a main frame including a number of vertical members having a length equal to the height of a dockboard pit,
a ramp pivotally mounted on the vertical members for movement from a cross travel position level with the dock to a position above the bed of a carrier,
a first hydraulic piston and cylinder assembly mounted on said frame for pivoting said ramp with respect to said vertical members,
a tread plate assembly mounted in said ramp for linear movement between a storage position in said ramp and an operable position forming a continuation of said ramp, said assembly including a tread plate,
a second hydraulic pistion and cylinder assembly for moving said tread plate assembly between the operative and storage positions, and
means connected between said second piston and said assembly for locking said tread plate assembly in the operative position with the tread plate in engagement with said ramp.

3 more elements

Dependencies are inferred from the claim text.

Dockboard with a tread plate lock mechanism

Life of this patent

Dockboard with a tread plate lock mechanism

Life of this patent

Abstract

Claims10