Hydraulic active boom suspension for a telehandler
First Claim
1. In a hydraulic suspension, for a boom of a loading vehicle, including at least one hydraulic cylinder having at least one chamber containing a piston coupled to a piston rod, a pump, a hydraulic oil tank, a direction control valve, a supply/return line coupling said control valve to said at least one chamber, a drain line coupling said control valve to said oil tank and a supply line coupling said control valve to said pump, and said control valve being selectively operable for either creating a connection between said pump and said chamber by way of said supply/return line or creating a connection between said oil tank and said chamber by way of said supply/return line, the improvement comprising:
- said hydraulic suspension further including a control unit;
a sensor coupled for sensing the position of said piston rod of said the hydraulic cylinder and being operable for generating a signal representing a sensed position of said piston rod;
said sensor being coupled to said control unit for conveying said generated signal to said control unit; and
a variable pressure-limiting unit coupled to said supply/return line and to said control unit and being controlled as a function of said signal generated by said sensor.
1 Assignment
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Accused Products
Abstract
A suspension for the boom of a loading vehicle includes a hydraulic cylinder for raising and lowering, or for extending and retracting (in the case of a telescopic cylinder), a boom. A direction control valve is provided for selectively routing hydraulic oil to and from at least a head-end chamber of the cylinder. A position sensor senses the position of the hydraulic piston rod, at the start of operation, and sends a sends a target signal representing this beginning position to a control unit which determines the difference between the target signal and a signal representing a current position of the piston rod. When this difference equals a preset difference threshold, a pressure-limiting unit, in the form of a valve or choke, is activated so as to control fluid flow to and from the head-end chamber so as to return the piston rod to its initial position which generated the target signal. Different embodiments have different valve component arrangements for influencing the reaction time of the suspension and/or for adapting the circuitry for use with single-acting, double-acting or telescopic boom cylinders.
34 Citations
13 Claims
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1. In a hydraulic suspension, for a boom of a loading vehicle, including at least one hydraulic cylinder having at least one chamber containing a piston coupled to a piston rod, a pump, a hydraulic oil tank, a direction control valve, a supply/return line coupling said control valve to said at least one chamber, a drain line coupling said control valve to said oil tank and a supply line coupling said control valve to said pump, and said control valve being selectively operable for either creating a connection between said pump and said chamber by way of said supply/return line or creating a connection between said oil tank and said chamber by way of said supply/return line, the improvement comprising:
- said hydraulic suspension further including a control unit;
a sensor coupled for sensing the position of said piston rod of said the hydraulic cylinder and being operable for generating a signal representing a sensed position of said piston rod;
said sensor being coupled to said control unit for conveying said generated signal to said control unit; and
a variable pressure-limiting unit coupled to said supply/return line and to said control unit and being controlled as a function of said signal generated by said sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- said hydraulic suspension further including a control unit;
Specification