Automatic steering for construction machines
First Claim
1. A construction machine comprising:
- a main frame;
ground engagement means disposed from said main frame to support and transport said machine along a path of travel;
a pair of said ground engagement means being disposed at opposite front corners of said main frame and rotatably connected thereto on individual steering axles;
power means to individually turn each of said front ground engagement means about its respective steering axle;
a steering sensor associated with one of said front ground engagement means and adapted to produce a steering voltage on either side of a null point indicating the magnitude and direction of a change in the path of travel of said machine from a reference extending along the path of travel;
steering detector means associated with each of said front ground engagement means including a rotatable member adapted to turn with the respective steering axles of each of said ground engagement means;
said steering detector means for said one front ground engagement means having a first feedback potentiometric means operably connected to its rotatable member for rotation in synchronism therewith to produce a first feedback signal and a second potentiometric means to produce a slave signal;
said steering detector means for said other front ground engagement means having a second feedback potentiometric means operably connected to its rotatable member for rotation in synchronism therewith to produce a second feedback signal;
and electrical means to receive said voltage signal from said steering sensor and produce an amplified power signal to control said power means to turn said one ground engagement means about its steering axle and to receive said slave signal and produce a second amplified power signal to control said power means to turn said other ground engagement means about its steering axle;
said electrical means being further adapted to receive said first and second feedback signals to change the null point of said steering sensor by the same amount and degree of steering correction and thereby incremently control both of said power means following said null point of said steering sensor and thereby turn said pair of ground engagement means in synchronism about their respective steering axles.
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Accused Products
Abstract
Automatic control means for the coordinated steering of front and rear pairs of individually steerable ground engagement means supporting a construction machine are disclosed wherein signals from front and rear steering sensors following a grade reference extending along the path of travel are fed to a panel readout/amplifier unit which sends error signals to a servo-valve system and feedback signals from potentiometers are produced to coordinate the degree of steer and the magnitude thereof with that of the sensed signals. In one embodiment the control means coordinate the parallel steering of the pairs of ground engagement means of a machine in the paving mode through the use of individual steering rams for each of the ground engagement means without the necessity of using steering linkages.
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Citations
10 Claims
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1. A construction machine comprising:
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a main frame; ground engagement means disposed from said main frame to support and transport said machine along a path of travel; a pair of said ground engagement means being disposed at opposite front corners of said main frame and rotatably connected thereto on individual steering axles; power means to individually turn each of said front ground engagement means about its respective steering axle; a steering sensor associated with one of said front ground engagement means and adapted to produce a steering voltage on either side of a null point indicating the magnitude and direction of a change in the path of travel of said machine from a reference extending along the path of travel; steering detector means associated with each of said front ground engagement means including a rotatable member adapted to turn with the respective steering axles of each of said ground engagement means; said steering detector means for said one front ground engagement means having a first feedback potentiometric means operably connected to its rotatable member for rotation in synchronism therewith to produce a first feedback signal and a second potentiometric means to produce a slave signal; said steering detector means for said other front ground engagement means having a second feedback potentiometric means operably connected to its rotatable member for rotation in synchronism therewith to produce a second feedback signal; and electrical means to receive said voltage signal from said steering sensor and produce an amplified power signal to control said power means to turn said one ground engagement means about its steering axle and to receive said slave signal and produce a second amplified power signal to control said power means to turn said other ground engagement means about its steering axle; said electrical means being further adapted to receive said first and second feedback signals to change the null point of said steering sensor by the same amount and degree of steering correction and thereby incremently control both of said power means following said null point of said steering sensor and thereby turn said pair of ground engagement means in synchronism about their respective steering axles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A construction machine comprising:
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a main frame; ground engagement means disposed from said main frame to support and transport said machine; a pair of said ground engagement means being disposed at opposite corners of said main frame along a front side thereof; each of said front ground engagement means being connected to said main frame on a vertical steering axle; power means to individually turn each of said front ground engagement means about its respective steering axle; one of said front ground engagement means having a steering sensor associated therewith with a sensor arm disposed for engagement with a steering reference extending along an adjacent side of said main frame to produce a steering signal on either side of a null point thereby indicating the direction and magnitude of a change in direction of said steering reference; a steering detector supported by said main frame and associated with each said front ground engagement means; each of said steering detectors including a rotatably member operably connected to the respective steering axle of its associated ground engagement means to rotate in synchronism therewith; said steering detector for said one front ground engagement means having a master feedback potentiometer and a slave sensor potentiometer each rotated in synchronism with said rotatable member of its steering detector; said steering detector for the other front ground engagement means having a slave feedback potentiometer rotated in synchronism with said rotatable member of its steering detector; and electrical means to receive said steering signal from said steering sensor and produce an amplified signal controlling said power means to turn said one ground engagement means about its steering axle and simultaneously turn said master feedback potentiometer through said steering detector whereby to compare said steering signal with an internally generated set point and nullify said steering signal and simultaneously rotate said slave sensor potentiometer an equal amount in the same direction to produce a second signal; said electrical means amplifying said second signal and simultaneously sending a power signal to control said power steering means of said other ground engagement means thereby rotating its associated slave feedback potentiometer whereby to send a feedback signal for comparison with said internally generated set point and nullify said second signal and turn said other ground engagement means in synchronism with said first ground engagement means. - View Dependent Claims (10)
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Specification