Lift gate device

Details Lift gate device Lift gate device

2002-07-15

2004-03-16

Ellis, Christopher P. (Department: 3651)

Material or article handling

Self-loading or unloading vehicles

Loading or unloading by other carrier or mover means, and...

C414S917000, C414S556000, C414S554000

Reexamination Certificate

active

06705825

ABSTRACT:

FIELD OF INVENTION
The present invention relates generally to lift gates for vehicles such as trucks, and specifically to a lift gate that folds when it is stored such that it provides a bumper at the rear of the vehicle.
BACKGROUND OF THE INVENTION
Lift gates are generally known in which a parallelogram linkage connected between a portion of the chassis at the rear of a truck and a platform is adapted to raise and lower the platform in such a way that the platform remains horizontal or substantially horizontal during the raising and lowering. The raising and lowering is typically accomplished hydraulically, with a hydraulic cylinder being connected in such a way that it can be used to rotate one of the links of the parallelogram, thus causing the rear portion of the parallelogram linkage to move either up or down. In a typical installation, the power is applied in order to raise the platform, and gravity is used to lower the platform.
The platforms of lift gates are typically stored either in a vertical position, in which they rest up against the back doors of the truck, or in a stored position under the rear chassis of the truck.
Typically the platform is pivotally mounted to what constitutes a vertical link at the rear end of the parallelogram linkage. The platform is ordinarily constructed in such a way that it can, while extending rearwardly from the parallelogram linkage, only pivot downwardly to a given predetermined position, typically one in which it is approximately parallel with the ground (horizontal). Further pivoting of the frame is prevented by mechanical interference between a flange or bracket and the rearward vertical link of the parallelogram linkage. To place the platform in a stored position, the platform is swung upward, through the vertical dead center position, and then inwardly and downwardly to overlie the parallelogram linkage itself.
In the typical stored position, the folded platform and linkage is visible from the rear of the truck. What is needed is a lift gate that folds up for storage into a configuration that provides a bumper such that the appearance of the rear of the vehicle is improved and that provides rear end impact protection.
SUMMARY OF THE INVENTION
The present invention meets the above-described need by providing a lift gate that folds into a storage configuration that provides a bumper at the rear of the vehicle.


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