Weighting circuit for an electrical torque signal in a drilling machine
First Claim
1. A weighting circuit for providing a trigger signal in response to a torque signal corresponding to torque developed in a hand tool, wherein the trigger signal influences operation of the tool, comprising first sensor means for comparing the amplitude of the torque signal with a first predetermined level and for providing an output signal when the amplitude of the torque signal exceeds the first predetermined level, integrator means for integrating the torque signal in response to the output signal of the first sensor means and for producing an integration value, second sensor means for comparing the integration value from said integrator means with a second predetermined level and for providing a corresponding output signal, and means for producing the trigger signal in response to the output of said second sensor means, wherein said first sensor means includes a first variable voltage divider, a first operational amplifier having an inverting input for receiving said torque signal and a non-inverting input coupled to said first variable voltage divider, and a first resistor coupled between said non-inverting input and the output of said first operational amplifier.
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Accused Products
Abstract
A weighting circuit operates to process a torque signal which may be produced by a strain gauge located within the handle of a drilling machine. The circuit includes a first sensor device for receiving the torque signal, and an integrator which integrates the torque signal when the amplitude of the torque signal exceeds a certain level as determined by the first sensor device. The output of the integrator is applied to a second sensor device which operates to switch off the machine when a predetermined integration value produced by the integrator is exceeded. The torque signal thus can be evaluated very thoroughly with the present circuit, so that improved control over the response of a drilling machine during blocking, jamming or twisting conditions, can be obtained.
42 Citations
12 Claims
- 1. A weighting circuit for providing a trigger signal in response to a torque signal corresponding to torque developed in a hand tool, wherein the trigger signal influences operation of the tool, comprising first sensor means for comparing the amplitude of the torque signal with a first predetermined level and for providing an output signal when the amplitude of the torque signal exceeds the first predetermined level, integrator means for integrating the torque signal in response to the output signal of the first sensor means and for producing an integration value, second sensor means for comparing the integration value from said integrator means with a second predetermined level and for providing a corresponding output signal, and means for producing the trigger signal in response to the output of said second sensor means, wherein said first sensor means includes a first variable voltage divider, a first operational amplifier having an inverting input for receiving said torque signal and a non-inverting input coupled to said first variable voltage divider, and a first resistor coupled between said non-inverting input and the output of said first operational amplifier.
Specification