Material or article handling – Self-loading or unloading vehicles – Conveyor
Reexamination Certificate
1999-03-19
2001-05-29
Keenan, James W. (Department: 3652)
Material or article handling
Self-loading or unloading vehicles
Conveyor
C414S525600, C414S813000
Reexamination Certificate
active
06238167
ABSTRACT:
TECHNICAL FIELD
This invention relates to a system for retaining an ejector blade, used in unloading material carried in a vehicle, in a secured load position when the ejector blade is not being used to remove material from the vehicle and, more particularly, to an ejector blade retaining system which locks the ejector blade in a fixed position when the ejector blade is moved into a load position, and retains the ejector blade in the load position until such time as the ejector blade is moved out from the load position to eject material from the vehicle.
BACKGROUND ART
Vehicles using ejector blades to remove material carried within the vehicle are well known, and the ejector blades of such vehicles are connected to a hydraulic cylinder or ram which is used to move the ejector blade from a load position to a discharge position for removing the material from the vehicle. When the ejector blade is in the load position, material may be freely loaded into the vehicle for transport to another location. When the ejector blade is moved from the load position towards the discharge position, materials loaded into the vehicle are discharged therefrom by the ejector blade pushing the materials from the body of the vehicle out through an unloading gate.
Because the ejector blade is secured to the hydraulic cylinder or ram for movement with the piston portion thereof, it has been experienced that when a vehicle such as an off-highway truck is traveling unloaded over rough and uneven terrain, the hydraulic cylinder will sometimes become partially extended. This unwanted extension of the hydraulic cylinder is referred to as cylinder “move out”. Such cylinder “move out” can result in damage to the hydraulic cylinder during subsequent loading operation, and the resultant movement of the ejector blade out from the load position during loading of the vehicle can result in the ejector blade being twisted during loading operations damaging the ejector blade and/or the hydraulic cylinder to which it is attached.
In U.S. Pat. No. 5,456,521, there is disclosed one attempt to overcome the problem of the ejector blade not being held or locked in the load position for use with an off-highway dump truck body. To this end, a pair of U-shaped brackets are used to engage a pair of pins secured to the carriage of the ejector blade when the ejector blade is in the load position. The U-shaped brackets are rotated to disengage the pins by operation of the hydraulic cylinders which are actuated in conjunction with the tilting of the body for dumping and thereby release the ejector blade so that it scrapes and cleans the inside of the truck body as the ejector blade moves towards the unloading gate.
In U.S. Pat. No. 4,576,540, there is disclosed another system for retaining an ejecting mechanism in a load position which utilizes electrically controlled solenoids to actuate tipping or tripping locks which retain the ejector mechanisms in a load position until such time as they are used to discharge material from the vehicle.
This invention is directed to overcoming one or more of the problems or concerns set forth above.
DISCLOSURE OF THE INVENTION
In the preferred embodiment of this invention, an ejector blade retaining system automatically locks the ejector blade in the loading position when the ejector blade has been retracted into the load position by operation of the hydraulic cylinder or ram to which it is attached. A pair of over-center ejector blade locking mechanisms are positioned, one on each side of the vehicle interior, to engage a lock roller carried by a pair of brackets secured one on each side of the ejector blade adjacent to the vehicle side walls. The use of a pair of over-center ejector blade locks positioned one on each side of the vehicle interior is preferred, in order to provide a positive locking of the ejector blade against racking forces when in the load position. As is known, when loading large unitary masses of materials such as broken portions of reinforced concrete or large rocks, if such materials are not centrally loaded, but loaded against one side of the ejector blade, racking forces occur which can damage the hydraulic cylinder and ejector roller system. By utilizing the over-center ejector blade locks in pairs, there is provided a positive stop or lock of each side of the ejector blade against the transmission of such racking forces which might otherwise occur during off-center loading.
The over-center ejector blade locks are engaged by the lock rollers when the ejector blade is retracted to its load position. The lock rollers engage the bight of a lock plate, causing the lock plate to rotate in a first direction about a pivot point, and compresses a compression spring as the lock plate continues to rotate in the first direction. Continued rotation of the lock plate in the first direction moves the connecting point between the lock plate and the compression spring over-center of the lock plate pivot point whereby the spring force will be released biasing the lock plate into a lock position and thereby holding the ejector blade in the load position until such time as it is desired to unload the vehicle.
When the hydraulic cylinder or ram is extended to move the ejector blade out from the load position to discharge material from the vehicle, the movement of the ejector blade outwardly from the load position will cause the lock plate to rotate in the opposite direction, thereby again compressing the compression spring until such time as the lock plate has been pivoted into a position wherein the connection between the lock plate and the compression spring again passes over-center. Upon passing over-center, the compression spring force is released and the lock plate will be held in an open position for reengaging the lock rollers to again hold the ejector blade in the load position when the hydraulic cylinder or ram has been retracted.
Related methods and other features and other advantages of the present invention will be apparent from the following description and the accompanying drawings.
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Kenny Peter M.
Prillinger Peter F.
Young David A.
Caterpillar S.A.R.L.
Hancock & Estabrook, LLP
Keenan James W.
Smith James R.
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