Energy source monitoring and control system for power tools
First Claim
1. A power tool energy source monitoring and control system comprising:
- a main power switch operable to connect series connected voltages V1 and V2 to a power tool motor voltage input;
a switch state control input coupled to the main power switch;
voltage measurement logic operable to determine V1 and V2;
comparison logic operable to determine a cutoff condition when V1, V2, or both V1 and V2 fade below a cutoff threshold for disconnecting the voltages V1 and V2 from the power tool; and
switch control logic operable to use the switch state control input to hold the main power switch in an ‘
ON’
state for an extension time despite determination of the cutoff condition.
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Accused Products
Abstract
An energy source monitoring system evaluates the state of an energy source and responsively controls a power tool or other device. The energy source may be, for example, a power tool battery pack that includes multiple individual battery packs connected in series. The energy source monitoring system may be incorporated into a power tool, screwdriver, flashlight, audio and/or video player, or any other device. The energy source monitoring system intelligently exercises control over the power applied to the device (e.g., to the motor in the device). In one implementation, the energy source monitoring system detects when voltages in the energy source have fallen below a cutoff level, yet allows the device to continue running until the operator finishes the current device operation (e.g. a miter saw cut, or playback of a song).
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Citations
25 Claims
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1. A power tool energy source monitoring and control system comprising:
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a main power switch operable to connect series connected voltages V1 and V2 to a power tool motor voltage input; a switch state control input coupled to the main power switch; voltage measurement logic operable to determine V1 and V2; comparison logic operable to determine a cutoff condition when V1, V2, or both V1 and V2 fade below a cutoff threshold for disconnecting the voltages V1 and V2 from the power tool; and switch control logic operable to use the switch state control input to hold the main power switch in an ‘
ON’
state for an extension time despite determination of the cutoff condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for power tool energy source monitoring and control, the method comprising:
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providing a switch state control input coupled to switch control logic and to a main power switch which connects series connected voltages V1 and V2 to a power tool motor voltage input; measuring V1; measuring V2; determining a cutoff condition when V1, V2, or both V1 and V2 fade below a cutoff threshold for disconnecting V1 and V2 from the power tool motor voltage input; and holding the main power switch in an ‘
ON’
state using the switch state control input for an extension time despite the cutoff condition, then releasing the main power switch to the ‘
OFF’
state. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A power tool energy source monitoring and control system comprising:
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a energy source input that accepts series connected voltages V1 and V2; a first voltage measurement point coupled to the energy source input; a second voltage measurement point coupled to the energy source input; a main power switch coupled to the energy source input and comprising a switch state control input; and a controller coupled to the first and second voltage measurement points and the main power switch; a memory coupled to the controller, the memory comprising; a cutoff threshold for disconnecting the series connected voltages V1 and V2 for stopping power tool operation; an operation threshold for connecting the series connected voltages V1 and V2 to allow power tool startup; a fading threshold for determining when voltages V1 and V2 are fading; and an energy source monitoring program operable to; measure the series connected voltage V1; measure the series connected voltage V2; determine when both V1 and V2 exceed the operation threshold and responsively hold the main power switch in an ‘
ON’
state using the switch state control input;determine when V1, V2, or both V1 and V2 fade below the fading threshold and responsively illuminate a warning indicator; and determine when V1, V2, or both V1 and V2 fade below the cutoff threshold for disconnecting V1 and V2 to stop power tool operation, and responsively hold the main power switch in an ‘
ON’
state for an extension time using the switch state control input. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A method for power tool control, comprising:
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identifying activation of a trigger switch for motor activation; despite activation of the trigger switch, limiting maximum motor speed to less than a final motor speed; detecting a state transition of the power tool; in response to the state transition, advancing the motor speed to the final motor speed. - View Dependent Claims (23, 24, 25)
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Specification