Apparatus for selectively positioning movable work element with preselected maximum velocity control
First Claim
1. An apparatus for selectively positioning a movable work element of a work vehicle at a plurality of preselected locations, comprising:
- a control element positionable at a plurality of preselected locations;
a spool valve having a neutral position and a number of operable positions;
first sensing means for delivering a first signal correlative to the location of said control element;
second sensing means for delivering a second signal correlative to the location of said work element;
comparator means for receiving said first and second signals and delivering a third signal correlative to the difference between said first and second signals;
means for receiving said third signal and delivering a desired velocity signal correlative to the magnitude of said third signal in response to said third signal being less than a preselected maximum valve and having a magnitude set to the preselected maximum value in response to said third signal being greater than the preselected maximum valve;
means for receiving and differentiating said second signal, and delivering an actual velocity signal correlative to the velocity of said movable work element;
means for receiving said actual and desired velocity signals and delivering a control signal correlative to the absolute difference between said actual and desired velocity signals and representative of a desired displacement of said spool valve from said neutral position; and
means for receiving said control signal and for delivering a pilot pressure to position said spool valve in response to the magnitude of said pilot pressure for controller the direction and velocity of movement of said work element so as to be in a direction to reduce the absolute magnitude of said third signal and said control signal.
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Accused Products
Abstract
Agricultural vehicles have heretofore lacked an adaptive implement hitch control and have correspondingly suffered from poor controllability of the hitch when the mass of the implement is varied significantly. The apparatus employs a sensor connected to and movable with the hitch such that a variable magnitude electrical signal is delivered which corresponds to the instantaneous hitch position. This signal is electronically differentiated to produce a signal indicative of actual hitch velocity. The hitch position and velocity signals are both used as feedback signals to close the control loop of the control and thereby provide an adaptive hitch velocity control.
30 Citations
14 Claims
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1. An apparatus for selectively positioning a movable work element of a work vehicle at a plurality of preselected locations, comprising:
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a control element positionable at a plurality of preselected locations; a spool valve having a neutral position and a number of operable positions; first sensing means for delivering a first signal correlative to the location of said control element; second sensing means for delivering a second signal correlative to the location of said work element; comparator means for receiving said first and second signals and delivering a third signal correlative to the difference between said first and second signals; means for receiving said third signal and delivering a desired velocity signal correlative to the magnitude of said third signal in response to said third signal being less than a preselected maximum valve and having a magnitude set to the preselected maximum value in response to said third signal being greater than the preselected maximum valve; means for receiving and differentiating said second signal, and delivering an actual velocity signal correlative to the velocity of said movable work element; means for receiving said actual and desired velocity signals and delivering a control signal correlative to the absolute difference between said actual and desired velocity signals and representative of a desired displacement of said spool valve from said neutral position; and means for receiving said control signal and for delivering a pilot pressure to position said spool valve in response to the magnitude of said pilot pressure for controller the direction and velocity of movement of said work element so as to be in a direction to reduce the absolute magnitude of said third signal and said control signal.
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2. An apparatus for selectively positioning a movable work element of a work vehicle at a plurality of preselected locations, comprising:
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a control element positionable at a plurality of preselected locations; a spool valve having a neutral position and a number of operable positions; first sensing means for delivering a first signal correlative to the location of said control element; second sensing means for delivering a second signal correlative to the location of said work element; comparator means for receiving said first and second signals and delivering a third signal correlative to the difference between said first and second signals; means for receiving said third signal and delivering a desired velocity signal wherein the magnitude of said desired velocity signal is directly proportional to the magnitude of said third signal when said third signal is less than a preselected maximum valve; means for delivering an actual velocity signal correlative to the velocity of said movable work element; means for receiving said actual and desired velocity signals and for delivering a control signal correlative to the absolute difference between said actual and desired velocity signals and being further correlative to a desired displacement of said spool valve from said neutral position; and hydraulic means for receiving said control signal and for delivering a pilot pressure to position said spool valve in response to the magnitude of said pilot pressure for controlling the direction and velocity of movement of said work element so as to he in a direction to reduce the absolute magnitude of said third signal and said control signal. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification