Material or article handling – Self-loading or unloading vehicles – With load-receiving portion – or significant section thereof,...
Reexamination Certificate
2000-05-26
2001-12-25
Keenan, James W. (Department: 3652)
Material or article handling
Self-loading or unloading vehicles
With load-receiving portion, or significant section thereof,...
C414S491000, C414S500000
Reexamination Certificate
active
06332746
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a locking mechanism for a roll-off container hoist, and more particularly, to a locking mechanism for securing a roll-off container to the roll-off container hoist when the hoist is in a transport orientation and for releasing the roll-off container when the hoist is moved from the transport orientation toward a hoisting orientation. The present invention also relates to a container hoist which includes such a locking mechanism, as well as a vehicle which carries a locking-mechanism-equipped container hoist. The present invention also provides a method of using the container hoist.
Vehicle-mounted container hoists are commonly used to load, unload and transport roll-off containers. Examples of such roll-off containers include conventional trash compactors and receptacles associated therewith. Such roll-off containers can weigh thousands of pounds. It is therefore extremely important that such containers remain secured to the vehicle and/or hoist during transport. Failure to keep the container secured during transport can pose a significant danger to the driver of the vehicle, as well as the public.
During transport, the roll-off containers are subject to significant jarring forces generated by changes in the vehicle's acceleration, abrupt steering, rapid braking, pot holes, and otherwise uneven road surfaces. There is consequently a need for a reliable and strong locking arrangement which positively secures the container to the vehicle and/or hoist.
Although simple manual locking arrangements can be used to secure the roll-off container to the vehicle, such manual arrangements disadvantageously depend upon the operator's memory. If the operator forgets to lock the container to the vehicle or to the hoist, a significant safety hazard will exist. Manual locking arrangements therefore provide less than optimum results.
In order to avoid the risk of having the operator forget to engage the locking mechanism, complex automatic locking arrangements can be used. Such locking mechanisms might include sensors which detect some aspect of the hoisting operation or the presence of the container, and a lock driver responsive to the sensor to actuate a locking device. Alternatively, such arrangements may include a spring or other resilient member which urges a locking member to engage the container and which is selectively disengaged to release the container using complex disengagement means. The resulting arrangements, however, can be relatively expensive to implement. In addition, they may be susceptable to failure, especially when exposed to wet and/or dusty environments, as well as road debris.
With regard to the spring or resilient member-based arrangements, it is possible for the spring or resilient member to become damaged by the weight of the containers.
Moreover, the containers are sometimes transported in an empty condition, but are also transported when full. There are consequently significant variations in the weight of the containers. This makes it extremely difficult to obtain a spring arrangement that reliably locks and disengages at the appropriate times.
There is consequently a need in the relevant art for a reliable, simple and inexpensive locking mechanism for use in a roll-off container hoist.
SUMMARY OF THE INVENTION
A primary object of the present invention is to overcome the disadvantages of the foregoing arrangements by providing a reliable, yet relatively simple and inexpensive locking mechanism for selectively restraining a roll-off container on a hoist bed.
Another object of the invention is to provide a hoist which includes the locking mechanism of the present invention.
Yet another object of the present invention is to provide a vehicle equipped with a hoist of the present invention.
Still another object of the present invention is to provide a method for hoisting a roll-off container using a hoist according to the present invention.
The foregoing and other objects are achieved using a locking mechanism which advantageously requires no springs or other resilient actuators and which is freely actuated by gravity in one direction and by engagement with a preferably rigid actuating surface in an opposite direction.
The locking mechanism according to the present invention is arranged so as to selectively restrain the roll-off container to the hoist bed. The locking mechanism includes a movable plate and a guide for the movable plate. The movable plate is freely movable through the guide, from a locking position to an unlocking position and vice versa. The mounting of the movable plate is such that when it is placed in the locking position, the movable plate projects out from the guide so as to restrain the container. By contrast, when the movable plate is placed in the unlocking position, the movable plate is withdrawn into the guide away from the container to thereby release the container.
Preferably, mounting of the movable plate is performed such that the movable plate automatically moves into the locking position when the hoist is in the substantially horizontal transport orientation and automatically moves into the unlocking position when the container hoist is taken out of the transport orientation toward the inclined hoisting orientation.
The automatic movement of the movable plate into the unlocking position preferably is achieved by arranging the movable plate so that, whenever the hoist is taken out of the transport orientation, gravity pulls the movable plate into the unlocking position. Automatic movement toward the locking position, by contrast, is achieved by providing the movable plate with a bearing surface and by providing an appropriately arranged actuating surface. When the hoist is brought into the transport orientation, the bearing surface is engaged by the actuating surface, and this engagement serves to urge the movable plate against gravity, into the locking position.
Preferably, the movable plate is pivotally mounted in the guide so as to pivot between the locking and unlocking positions.
The present invention also provides a container hoist for loading, unloading and transporting a roll-off container. The container hoist includes a frame, a hoist bed pivotally mounted to the frame; and at least one locking mechanism for selectively restraining a roll-off container to the hoist bed. The locking mechanism includes a guide formed in the hoist bed and a movable plate mounted in the guide. The movable plate of the locking mechanism is freely movable through the guide, between a locking position and an unlocking position. In particular, the movable plate is mounted so that when the movable plate is in the locking position, the movable plate projects out from the guide so as to restrain the roll-off container. When the movable plate is in the unlocking position, by contrast, the movable plate is withdrawn into the guide away from the roll-off container to thereby release the roll-off container.
The present invention also provides a vehicle for loading, unloading and transporting a roll-off container. The vehicle includes a vehicle chassis and a container hoist. The container hoist includes a frame mounted to the vehicle chassis, a hoist bed pivotally mounted to the frame, and at least one locking mechanism for selectively restraining a roll-off container to the hoist bed. The locking mechanism includes a guide formed in the hoist bed and a movable plate mounted in the guide. The movable plate of the locking mechanism is freely movable through the guide, between a locking position and an unlocking position. In particular, the movable plate is mounted so that when the movable plate is in the locking position, the movable plate projects out from the guide so as to restrain the roll-off container. When the movable plate is in the unlocking position, by contrast, the movable plate is withdrawn into the guide away from the roll-off container to thereby release the roll-off container.
The present invention also provides a vehicle-mounted roll-off hoist for loading, transporting and u
Lang Allen M.
Shaw Gordon C.
Delaware Capital Formation Inc.
Keenan James W.
Liniak, Berenato, Longacre & White LLC
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