PROPORTIONAL COUNTERBALANCE SYSTEM FOR MOWER CUTTING UNITS
First Claim
1. A mower for cutting grass growing on a turf surface, which comprises:
- (a) a traction vehicle supported for rolling over the ground by a plurality of wheels, wherein at least some of the wheels are powered by a traction drive system to propel the traction vehicle over the ground;
(b) a grass cutting unit operatively connected to the traction vehicle, wherein the grass cutting unit is supported in a mowing position such that at least some of the weight of the grass cutting unit is directly borne by the ground when the cutting unit is in the mowing position;
(c) a hydraulic cylinder coupled to the cutting unit to lift the cutting unit out of engagement with the ground to place the cutting unit into a raised transport position out of engagement with the ground and to lower the cutting unit into engagement with the ground to place the cutting unit into the mowing position;
(d) a lift and lower hydraulic circuit for the cylinder with the hydraulic circuit having a fluid supply circuit to the cylinder and a fluid return circuit from the cylinder;
(e) a counterbalance system that is effective to shift desired amounts of the weight of the cutting unit between the ground and the traction vehicle, which comprises;
(i) a proportional hydraulic valve connected between the supply circuit and the return circuit to establish a backpressure in the return circuit that counterbalances at least a portion of the weight of the cutting unit on the ground by shifting the portion of weight to the traction vehicle; and
(ii) an electronic controller operatively connected to the proportional valve with the controller being responsive to a variable input parameter for substantially continuously and infinitely varying the backpressure being provided in the return circuit in concert with variation in the input parameter.
1 Assignment
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Accused Products
Abstract
A proportional counterbalance system comprises an electronic controller operatively connected to a proportional hydraulic control valve to substantially continuously and infinitely adjust the backpressure in a fluid return circuit from the lift and lower cylinders of a plurality of cutting units on a mower. The backpressure is infinitely adjusted within a band between a minimum and a maximum backpressure in concert with a varying input parameter to the controller to transfer desired amounts of weight of the cutting units from the ground to the traction vehicle of the mower to enhance traction as needed. A wide variety of input parameters can be used, including a selected operating condition of the mower, a selected environmental condition of the turf surface being mowed, the actual, real time location of the mower on the turf surface, altitude above sea level, and manual input from the operator.
19 Citations
20 Claims
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1. A mower for cutting grass growing on a turf surface, which comprises:
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(a) a traction vehicle supported for rolling over the ground by a plurality of wheels, wherein at least some of the wheels are powered by a traction drive system to propel the traction vehicle over the ground; (b) a grass cutting unit operatively connected to the traction vehicle, wherein the grass cutting unit is supported in a mowing position such that at least some of the weight of the grass cutting unit is directly borne by the ground when the cutting unit is in the mowing position; (c) a hydraulic cylinder coupled to the cutting unit to lift the cutting unit out of engagement with the ground to place the cutting unit into a raised transport position out of engagement with the ground and to lower the cutting unit into engagement with the ground to place the cutting unit into the mowing position; (d) a lift and lower hydraulic circuit for the cylinder with the hydraulic circuit having a fluid supply circuit to the cylinder and a fluid return circuit from the cylinder; (e) a counterbalance system that is effective to shift desired amounts of the weight of the cutting unit between the ground and the traction vehicle, which comprises; (i) a proportional hydraulic valve connected between the supply circuit and the return circuit to establish a backpressure in the return circuit that counterbalances at least a portion of the weight of the cutting unit on the ground by shifting the portion of weight to the traction vehicle; and (ii) an electronic controller operatively connected to the proportional valve with the controller being responsive to a variable input parameter for substantially continuously and infinitely varying the backpressure being provided in the return circuit in concert with variation in the input parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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8. The mower of claim 8, wherein each cutting unit is lifted and lowered by a separate cylinder.
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18. A mower for cutting grass growing on a turf surface, which comprises:
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(a) a traction vehicle supported for rolling over the ground by a plurality of wheels, wherein at least some of the wheels are powered by a traction drive system to propel the traction vehicle over the ground; (b) a grass cutting unit operatively connected to the traction vehicle, wherein the grass cutting unit is supported in a mowing position such that at least some of the weight of the grass cutting unit is directly borne by the ground when the cutting unit is in the mowing position; (c) a counterbalance system that is effective to proportionally shift desired amounts of the weight of the cutting unit between the ground and the traction vehicle, which comprises; (i) a proportionally adjustable weight transfer mechanism that counterbalances at least a portion of the weight of the cutting unit on the ground by shifting varying portions of weight to the traction vehicle in a substantially infinite adjustment manner; and (ii) an electronic controller operatively connected to the weight transfer mechanism with the controller being responsive to a variable input parameter for substantially continuously and infinitely adjusting the weight transfer mechanism in concert with variation in the input parameter. - View Dependent Claims (19, 20)
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Specification