Materials handling vehicle monitoring a pressure of hydraulic fluid within a hydraulic structure
First Claim
1. A materials handling vehicle comprising:
- a support structure including a fixed member;
a movable assembly coupled to said support structure;
said support structure further comprising lift apparatus to effect movement of said movable assembly relative to said support structure fixed member, said lift apparatus including hydraulic structure comprising at least one ram/cylinder assembly, at least one hydraulic fluid line in communication with said at least one ram/cylinder assembly, and a hydraulic system that supplies a pressurized fluid to said at least one ram/cylinder assembly via said at least one hydraulic fluid line; and
control structure to monitor a pressure of the pressurized fluid within said hydraulic structure and to implement a response routine if the monitored pressure of the pressurized fluid within said hydraulic structure falls below a threshold pressure during a lowering or lifting operation of the movable assembly.
1 Assignment
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Accused Products
Abstract
A materials handling vehicle is provided comprising: a support structure including a fixed member; a movable assembly coupled to the support structure; a hydraulic system; and a control system. The support structure further comprises lift apparatus to effect movement of the movable assembly relative to the support structure fixed member. The lift apparatus includes at least one ram/cylinder assembly. The hydraulic system includes a motor, a pump coupled to the motor to supply a pressurized fluid to the at least one ram/cylinder assembly, and at least one electronically controlled valve associated with the at least one ram/cylinder assembly. The control structure may estimate a speed of the movable assembly from a speed of the motor and control the operation of the at least one valve using the estimated movable assembly speed.
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Citations
26 Claims
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1. A materials handling vehicle comprising:
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a support structure including a fixed member; a movable assembly coupled to said support structure; said support structure further comprising lift apparatus to effect movement of said movable assembly relative to said support structure fixed member, said lift apparatus including hydraulic structure comprising at least one ram/cylinder assembly, at least one hydraulic fluid line in communication with said at least one ram/cylinder assembly, and a hydraulic system that supplies a pressurized fluid to said at least one ram/cylinder assembly via said at least one hydraulic fluid line; and control structure to monitor a pressure of the pressurized fluid within said hydraulic structure and to implement a response routine if the monitored pressure of the pressurized fluid within said hydraulic structure falls below a threshold pressure during a lowering or lifting operation of the movable assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification