Safety system and method for power tools
OwnerDennis E. Lewisinventor
Life of this patent
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Abstract
A safety system for a power tool having a motor and a cutting tool driven by the motor includes a control device configured to detect a direct contact of a conductive material with the cutting tool, the direct contact of the conductive material with the cutting tool defining a contact event, and a braking device movable between a retracted position and an engaged position. The control device is configured to interrupt electrical power to the motor and control the braking device to the engaged position when the contact event is detected.
Claims17
A safety system for a power tool having a motor and a cutting tool driven by the motor, the safety system comprising:
- a control device configured to detect a direct contact of a conductive material with the cutting tool, the direct contact of the conductive material with the cutting tool defining a contact event;
- a contact wiper electrically coupled to the control device, the contact wiper contacting the cutting tool and transmitting a voltage to the cutting tool;
- and
- a braking device movable between a retracted position and an engaged position;
- wherein the control device is configured to interrupt electrical power to the motor and control the braking device to the engaged position when the contact event is detected.
A power tool, comprising:
- a motor;
- a cutting tool driven by the motor;
- and
- a safety system configured to interrupt electrical power to the motor and to stop rotation of the cutting tool upon detection of a contact event with the cutting tool, the safety system including a control device configured to detect the presence of the contact event and a braking device configured to stop rotation of the cutting tool subsequent to the contact event;
- wherein the control device is configured to interrupt electrical power to the motor and to actuate the braking device when the contact event is detected
- wherein the safety system includes a contact wiper electrically coupled to the control device, the contact wiper contacting the cutting tool and transmitting a voltage to the cutting tool.
A power tool, comprising:
- a motor;
- a cutting tool driven by the motor;
- and
- a safety system configured to interrupt electrical power to the motor and to stop rotation of the cutting tool upon detection of a contact event with the cutting tool, the safety system including a control device configured to detect the presence of the contact event and a braking device configured to stop rotation of the cutting tool subsequent to the contact event;
- wherein the control device is configured to interrupt electrical power to the motor and to actuate the braking device when the contact event is detected
- wherein the control device is an operational amplifier;
- and
- wherein the operational amplifier is configured to output a signal to interrupt electrical power to the motor and control the braking device to stop rotation of the cutting tool when a second pin voltage of the operational amplifier is below a first pin voltage of the operational amplifier.
A method for operating a power tool, comprising the steps of:
- activating a safety system for the power tool, wherein in an activated state a braking device is held in touching contact with a cutting tool or rotating hub of the power tool and power is not supplied to a motor of the power tool;
- resetting the safety system to disengage the braking device from the cutting tool or the rotating hub and to allow power to flow to the motor to rotate the cutting tool;
- and
- detecting a contact event of a conductive material with the cutting tool;
- upon detection of the contact event, interrupting a flow of power to the motor and engaging the braking device with the cutting tool or rotating hub to non-destructively stop rotation of the cutting tool;
- and
- touching a conductive material to the cutting tool during rotation of the cutting tool to non-destructively test operation of a safety system of the power tool.
Dependencies are inferred from the claim text.