Programmable ride control

• US 5,520,499 A
• Filed: 07/12/1994
• Issued: 05/28/1996
• Est. Priority Date: 07/12/1994
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Ufheil, Steven T., Rector, Stephen W.
• Primary Examiner(s): Underwood, Donald W.
• Application Number:
  US08/274,085
• Time in Patent Office: 686 Days
• Field of Search: 414/685, 414/719, 60/413
• US Class Current: 414/685
• CPC Class Codes: E02F 9/2207 for reducing or compensating oscillations
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels

Abstract

The present invention provides a ride control 100 for a machine having an implement and a hydraulic lift cylinder. The hydraulic lift cylinder is adapted for moving the implement to and between a plurality of positions. The ride control is controllable between a RIDE CONTROL ON mode, a RIDE CONTROL OFF mode and a RIDE CONTROL PROGRAM mode. In the RIDE CONTROL ON mode, the ride control connects and disconnects an accumulator from the hydraulic lift cylinder circuit as a function of machine velocity. In the RIDE CONTROL OFF mode, the ride control disconnects the accumulator from the hydraulic lift cylinder circuit. In the RIDE CONTROL PROGRAM mode, the ride control sets the threshold for activation of the ride control to the current machine velocity.

Claims

1. In a machine having an implement and a hydraulic lift cylinder for moving the implement to and between a plurality of positions, a ride control comprising:

means for sensing a velocity of the machine and responsively producing a velocity signal;

a hydraulic accumulator;

a control valve connected to and between said hydraulic accumulator and the lift cylinder, said control valve having an open state in which hydraulic fluid pass between the lift cylinder and said hydraulic accumulator and a closed state in which hydraulic fluid is prevented from passing between the lift cylinder and said hydraulic accumulator;

switching means for generating a ride control mode signal, said ride control signal having one of a first, second and third values, corresponding to one of a RIDE CONTROL ON mode, a RIDE CONTROL OFF mode and a RIDE CONTROL PROGRAM mode, respectively; and

control means, connected to said switching means and said control valve, for receiving said ride control mode signal and said velocity signal, and for

opening said control valve in response to said velocity signal being greater than a first predetermined magnitude, if said ride control mode signal is equal to said first value,

closing said control valve, if said ride control mode signal is equal to said second value, and

setting said first predetermine value equal to said velocity signal, if said ride control mode signal is equal to said third value.

2. The invention, as set forth in claim 1, wherein said control means includes means for closing said control valve in response to said velocity signal being less than a second predetermined value, if said ride control mode signal is equal to said first value.

3. In a machine having an implement and a hydraulic lift cylinder for moving the implement to and between a plurality of positions, a ride control comprising:

means for sensing a velocity of the machine and responsively producing a velocity signal;

a hydraulic accumulator;

a control valve connected to and between said hydraulic accumulator and the lift cylinder, said control valve having an open state in which hydraulic fluid pass between the lift cylinder and said hydraulic accumulator and a closed state in which hydraulic fluid is prevented from passing between the lift cylinder and said hydraulic accumulator;

a pilot valve hydraulically coupled with said control valve;

switching means for generating a ride control mode signal, said ride control signal having one of a first, second and third values corresponding to one of a RIDE CONTROL ON mode, a RIDE CONTROL OFF mode and a RIDE CONTROL PROGRAM mode, respectively; and

control means, connected to said switching means and said pilot valve, for receiving said ride control mode signal and said velocity signal, and for

delivering a first electrical signal to said pilot valve in response to said velocity signal being greater than a first predetermined magnitude, if said ride control mode signal is equal to said first value,

delivering a second electrical signal to said pilot valve, if said ride control mode signal is equal to said second value, and

setting said first predetermined value equal to said velocity signal, if said ride control mode signal is equal to said third value.

4. A method for controllably engaging and disengaging a ride control in a machine having an implement and a hydraulic lift cylinder for moving the implement to and between a plurality of positions, comprising:

sensing a velocity of the machine and responsively producing a velocity signal;

producing a ride control signal, said ride control signal having one of a first, second and third values corresponding to a one of a RIDE CONTROL ON mode, a RIDE CONTROL OFF mode and a RIDE CONTROL PROGRAM mode, respectively;

producing a first control signal in response to said velocity signal being greater than a first predetermined magnitude, if said ride control signal is equal to said first value;

producing a second control signal, if said ride control signal is equal to said second value;

setting said first predetermined magnitude equal to said velocity signal, if said ride control mode signal is equal to said third signal;

allowing fluid to flow between a hydraulic accumulator and the lift cylinder in response to said first control signal; and

preventing fluid from flowing between the hydraulic accumulator and the lift cylinder in response to the second control signal.