Hydraulic circuit for a pipelayer
First Claim
1. A hydraulic circuit for a pipelayer machine having an extensible boom pivotally mounted to a vehicle, an extensible hoist cable extending from the outer end of said boom, and a counterweight extending from one side of said vehicle to counterbalance said boom, said circuit comprising:
- a boom lift motor operatively connected for lifting said boom;
a hoist motor operatively connected for extending and retracting said hoist cable;
a first source of pressurized fluid for supplying fluid by way of first circuit means for low speed operation of said motors;
first valve means for selectively communicating fluid from said first source of fluid to one of said motors;
a second source of pressurized fluid for supplying fluid by way of second circuit means for high speed operation of said motors;
second valve means for selectively communicating fluid from said second source to said one of said motors;
control means interconnecting said first and second valve means and operative over a first range of movement for moving said first valve means into communicating position and operative over a second range of movement for moving said first valve means to a non-communicating position and simultaneously therewith move said second valve means to a communicating position.
1 Assignment
0 Petitions
Accused Products
Abstract
A pipelayer comprising a tractor vehicle having an extensible boom pivotally mounted to the vehicle and extended to one side thereof is provided with a hydraulic circuit for performing all operations of the boom and accessories. The hydraulic circuitry comprises a low volume source of fluid selectively directable to a first plurality of the motors of the machine for operating these motors at a low speed and a second source of fluid including circuits for selectively directing the fluid to a second plurality of motors including some of the first motors. Two motors within the circuit may be operated from either of the sources of fluid. Valve means are interconnected for simultaneous control for selectively directing fluid from either of the sources to the two motors.
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Citations
20 Claims
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1. A hydraulic circuit for a pipelayer machine having an extensible boom pivotally mounted to a vehicle, an extensible hoist cable extending from the outer end of said boom, and a counterweight extending from one side of said vehicle to counterbalance said boom, said circuit comprising:
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a boom lift motor operatively connected for lifting said boom; a hoist motor operatively connected for extending and retracting said hoist cable; a first source of pressurized fluid for supplying fluid by way of first circuit means for low speed operation of said motors; first valve means for selectively communicating fluid from said first source of fluid to one of said motors; a second source of pressurized fluid for supplying fluid by way of second circuit means for high speed operation of said motors; second valve means for selectively communicating fluid from said second source to said one of said motors; control means interconnecting said first and second valve means and operative over a first range of movement for moving said first valve means into communicating position and operative over a second range of movement for moving said first valve means to a non-communicating position and simultaneously therewith move said second valve means to a communicating position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A hydraulic pipelayer comprising the combination of a vehicle, an extensible boom pivotally mounted on and extending from one side of said vehicle, a counterweight mounted on and extending from the vehicle on the opposite side from said boom, and a hydraulic manipulating system, said hydraulic system comprising:
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a boom lift motor for lifting said boom; a boom extension motor for extending said boom; a hoist motor operatively connecting for extending and retracting a cable from the outer end of said boom; first circuit means including a first source of pressurized fluid for supplying fluid for operation of at least two of said motors for a low speed of operation of said motors; second circuit means including a second source of pressurized fluid for supplying fluid for at least said two of said motors for high speed operation of said motors; first and second valve means operative for controlling the direction of said pressurized fluid to selected ones of said motors; and
,control means interconnecting at least a pair of valves of said valve means for sequential movement over a first range of movement for directing fluid from one of said sources to one of said motors and thereafter over a second range of movement for directing fluid from the other of said sources to said motor. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification