Control of torque in floor maintenance tools by drive motor load
First Claim
1. An automatic tool torque compensator for a surface maintenance machine including means for raising and lowering one or more surface maintenance tools, motor means for driving the surface maintenance tools, means for sensing the load in said motor means and for providing an electrical signal representative thereof, means for selecting a desired tool torque from a plurality of possible tool torques and for providing an electrical signal representative thereof, and means for utilizing said electrical signals to control the operation of said means for raising and lowering the surface maintenance tools to maintain the desired tool torque.
1 Assignment
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Accused Products
Abstract
An automatic tool torque compensator for a surface maintenance machine such as a sweeper or scrubber includes an actuator for raising and lowering one or more rotatable surface maintenance tools and one or more electric or hydraulic motors for driving the tools. There is a circuit for sensing the current load in at least one of the electric motors, or the differential pressure in one or more of the hydraulic motors, and providing a signal representative thereof. There is a circuit for manually selecting a desired tool torque to be applied from a plurality of possible tool torques and for providing an electrical signal representative thereof. The electrical signal representative of the desired tool torque to be applied to the tools and the drive motor load current signal or the differential hydraulic pressure signal representative of actual tool torque applied to the tools are used to control the actuator for raising and lowering the surface maintenance tools. This automatically varies the pressure of the tools against the surface to maintain a desired torque in the tools at a nearly constant value even though the surface may vary in its resistance to the tools due to variations in its elevation or texture, or the degree of soilage on it.
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Citations
14 Claims
- 1. An automatic tool torque compensator for a surface maintenance machine including means for raising and lowering one or more surface maintenance tools, motor means for driving the surface maintenance tools, means for sensing the load in said motor means and for providing an electrical signal representative thereof, means for selecting a desired tool torque from a plurality of possible tool torques and for providing an electrical signal representative thereof, and means for utilizing said electrical signals to control the operation of said means for raising and lowering the surface maintenance tools to maintain the desired tool torque.
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11. An automatic tool torque compensator for a surface maintenance machine including means for raising and lowering one or more surface maintenance tools, motor means for driving the surface maintenance tools, means for sensing the load in said motor means for driving the surface maintenance tools and for providing an electrical signal representative thereof,
means for providing a plurality of discrete electrical signals each representative of a desired level of tool torque, amplifying means having one input of the electrical signal representative of motor load and another input of one of said plurality of discrete electrical signals, with said latter electrical signal controlling the gain of said amplifying means, with the output of said amplifying means being a signal representative of motor load modified in accordance with a desired level of tool torque, comparison means connected to said amplifying means and comparing the output thereof with a reference electrical signal to control the means for raising and lowering said one or more surface maintenance tools to maintain the desired level of tool torque.
Specification