Hydraulic control system for a street sweeper
First Claim
1. A street sweeper having a frame with an engine mounted on said frame for powering the street sweeper for movement along a sweeping surface, a series of operating mechanisms mounted on said frame to assist in a street sweeping pick-up operation and a plurality of hydraulic motors arranged to power said operating mechanisms and a series of hydraulic components arranged to move said operating mechanisms into a street sweeping pick-up position and into a retracted position wherein the improvement comprises:
- a variable volume and reversible hydraulic pump which is suitably driven by said engine and operatively associated with said plurality of hydraulic motors when said pump is regulated to produce fluid pressure flow in a first direction and which is operatively associated with said series of hydraulic components when said pump is regulated to produce fluid pressure flow in a second direction;
means to selectively regulate said pump as a variable volume pump for producing fluid pressure flow in said first direction at a consistent preset output irrespective of the driving speed of said engine and to selectively regulate said pump as a fixed volume pump for producing reversed fluid pressure flow in said second direction, and a hydraulic system including a first closed loop circuit for interconnecting said variable volume reversible pump with said plurality of hydraulic motors and back to said pump for directing operating hydraulic pressure flow in said first direction and a second closed loop circuit for interconnecting said variable volume reversible pump with said series of hydraulic components and back to said pump for directing operating hydraulic pressure flow in said second direction.
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Accused Products
Abstract
A street sweeper having a frame with a cab carried thereon. An engine is mounted on the frame for powering the sweeper. A series of operating mechanisms are supported on the frame for assisting in a sweepings pick-up operation. A series of hydraulic motors are provided with each being operatively associated with one of the mechanisms for operating the same. A single variable and reversible flow piston pump is operatively connected to the hydraulic motors and the hydraulic mechanisms for operating them at a constant speed. The engine operates the piston pump with a variable speed input. A control mechanism is mounted in the cab, and electrical circuit means is connected between the control mechanism and the piston pump and cooperable with said control mechanism enabling for selective operation of the mechanisms at selective rotational speeds for assisting in a sweepings pick-up operation.
27 Citations
10 Claims
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1. A street sweeper having a frame with an engine mounted on said frame for powering the street sweeper for movement along a sweeping surface, a series of operating mechanisms mounted on said frame to assist in a street sweeping pick-up operation and a plurality of hydraulic motors arranged to power said operating mechanisms and a series of hydraulic components arranged to move said operating mechanisms into a street sweeping pick-up position and into a retracted position wherein the improvement comprises:
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a variable volume and reversible hydraulic pump which is suitably driven by said engine and operatively associated with said plurality of hydraulic motors when said pump is regulated to produce fluid pressure flow in a first direction and which is operatively associated with said series of hydraulic components when said pump is regulated to produce fluid pressure flow in a second direction; means to selectively regulate said pump as a variable volume pump for producing fluid pressure flow in said first direction at a consistent preset output irrespective of the driving speed of said engine and to selectively regulate said pump as a fixed volume pump for producing reversed fluid pressure flow in said second direction, and a hydraulic system including a first closed loop circuit for interconnecting said variable volume reversible pump with said plurality of hydraulic motors and back to said pump for directing operating hydraulic pressure flow in said first direction and a second closed loop circuit for interconnecting said variable volume reversible pump with said series of hydraulic components and back to said pump for directing operating hydraulic pressure flow in said second direction. - View Dependent Claims (2, 3)
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- 4. A street sweeper, a frame and a cab carried thereon, an engine on the frame for powering the sweeper, a series of operating mechanisms on the frame for assisting in a sweepings pick-up operation, a series of hydraulic motors each operatively associated with one of said mechanisms for operating the same, a single variable and reversible flow piston pump for operating said hydraulic motors and said hydraulic mechanisms at a constant speed, said engine operating said piston pump with a variable speed input, a control mechanism in said cab, and electrical circuit means between said control mechanism and said piston pump for operating said mechanisms at selective rotational speeds for assisting in a sweepings pick-up operation.
- 6. A street sweeper, a frame, and engine on the frame for powering the sweeper, a series of rotating mechanisms on the frame for assisting in a sweepings pick-up operation, a series of hydraulic motors each operatively associated with one of said mechanisms for operating the same, a single variable volume and reversible flow piston pump for operating said hydraulic motors and said hydraulic mechanisms at a constant speed, said engine operating said piston pump with a variable speed input, a control mechanism and electrical circuit means between said control mechanism and said piston pump for operating said mechanisms at selective rotational speeds for assisting in a sweepings pick-up operation which rotational speeds are independent of engine speed.
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9. A street sweeper having a frame, a cab positioned at the forward end of the frame, broom means on the frame, a hopper for receiving sweepings positioned on the frame behind the cab, means on the frame behind the cab for loading sweepings from the broom means to the hopper, lift mechanism for the hopper, lift cylinder means connected to the lift mechanism for moving the hopper through an arc over the cab to a dumping position for unloading sweepings into a truck at a forward end of the sweeper, a dump door on said hopper and a hydraulic door cylinder for opening and closing the dump door, a hydraulic circuit connecting said lift cylinder means and said hydraulic door cylinder, and only a single manually actuated hydraulic control valve operatively connected to said hydraulic circuit for sequentially operating the lift cylinder means to cause the lift mechanism to lift the hopper over the cab and for then actuating the door cylinder to open the door to cause the contents of the hopper to be unloaded, the single manually actuated hydraulic control valve being reversibly operable to first cause the door cylinder to close the dump door and to maintain the door closed while actuating the lift mechanism to return the hopper over the cab to a position for receiving sweepings.
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10. A street sweeper having a frame, broom means on the frame, a hopper for receiving sweepings positioned on the frame, means on the frame for loading sweepings from the broom means to the hopper, lift mechanism for the hopper, lift cylinder means connected to the lift mechanism for moving the hopper to a dumping position for unloading sweepings into a truck at a forward end of the sweeper, a dump door on said hopper and a hydraulic door cylinder for opening and closing the dump door, a hydraulic circuit connecting said lift cylinder means and said hydraulic door cylinder, and only a single manually actuated hydraulic control valve operatively connected to said hydraulic circuit for sequentially operating the lift cylinder means to cause the lift mechanism to lift and move the hopper to a dumping position and for then actuating the door cylinder to open the door to cause the contents of the hopper to be unloaded, the single manually actuated hydraulic control valve being reversibly operable to first cause the door cylinder to close the dump door and to maintain the door closed while actuating the lift mechanism to return the hopper to a position on the frame for receiving sweepings.
Specification