Electric sander and motor control therefor
First Claim
Patent Images
1. A hand held orbital sander, comprising:
- a. a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing; and
b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value wherein the motor controller slows the motor by reverse commutation when it changes the speed of the motor from sanding speed to idle speed.
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Accused Products
Abstract
A hand held orbital sander has a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing. A motor controller is coupled to the motor. The motor controller changes the speed of at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changes the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value. The sander may have a mechanical brake that brakes the orbit mechanism and the motor controller also dynamically brakes the motor.
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Citations
18 Claims
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1. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing; and b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value wherein the motor controller slows the motor by reverse commutation when it changes the speed of the motor from sanding speed to idle speed. - View Dependent Claims (2, 3, 4, 6, 7)
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5. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing; and b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value wherein the sander has an on/off switch and the motor controller senses whether the on/off switch is on when the sander is first coupled to a source of power and if it is, does not start the motor until the on/off switch is first switched off and then back on.
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8. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated AC synchronous motor disposed therein and an orbit mechanism disposed beneath the housing; and b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value.
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9. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated brushless DC motor disposed therein and an orbit mechanism disposed beneath the housing; and b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value.
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10. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing; and b. a motor controller coupled to the motor, the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changing the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value wherein the sander has an on/off switch and the motor controller senses a collapse in an input voltage when the on-off switch is turned off and reverse commutates the motor to brake it.
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11. A hand held orbital sander, comprising:
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a. a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing; b. a motor controller coupled to the motor; c. a current sensor coupled to the motor controller that provides a signal indicative of motor current; and d. the motor controller changing the speed at which it runs the motor from an idle speed to a sanding speed based upon at least one of change in motor current and change in motor speed as the sander is removed from a work piece and changing the speed at which it runs the motor from sanding speed to idle speed based upon at least one of change in motor current and change in motor speed as the sander is applied to the work piece. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification