Electro-hydraulic brush down force control
First Claim
1. A floor cleaning machine having a movable cleaning element and means for driving said cleaning element, means for applying a floor-directed fluid pressure on said movable cleaning element during use thereof, including a fluid pressure regulator, said regulator including a movable valve element and an electrical coil for controlling the position of said movable valve element,a feedback circuit for controlling current through said coil including a source of power connected to said coil, means for sensing current flow in said circuit through said coil, means for comparing sensed current with an established desired current, and means for varying current applied to said coil in accordance with the comparison between actual sensed current and said established current to maintain current flow through said coil at a desired level to maintain a desired floor-directed fluid pressure on said movable cleaning element.
4 Assignments
0 Petitions
Accused Products
Abstract
A floor cleaning machine of the type having a fluid driven scrub brush utilizes fluid pressure for applying down force on the scrub brush to a floor surface being cleaned. The fluid pressure applied is controlled by a fluid pressure regulator which has a movable valve element and an electrical coil for controlling the position of the movable valve element. There is a feedback circuit for controlling current through the coil which includes a source of power and a pulse width modulation switching device. The switching device in turn is controlled by a comparison between the current sensed in the coil circuit and an operator set value for the desired current to provide a desired down force on the cleaning brush.
22 Citations
7 Claims
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1. A floor cleaning machine having a movable cleaning element and means for driving said cleaning element, means for applying a floor-directed fluid pressure on said movable cleaning element during use thereof, including a fluid pressure regulator, said regulator including a movable valve element and an electrical coil for controlling the position of said movable valve element,
a feedback circuit for controlling current through said coil including a source of power connected to said coil, means for sensing current flow in said circuit through said coil, means for comparing sensed current with an established desired current, and means for varying current applied to said coil in accordance with the comparison between actual sensed current and said established current to maintain current flow through said coil at a desired level to maintain a desired floor-directed fluid pressure on said movable cleaning element.
Specification