초록 ▼

A method and device for sensing the distance between a first object and a second object so as to activate or facilitate predetermined actions when the distance has attained a certain value. A person (1) (first object) holds a handle (2) of a power tool, the handle being connected to a function gener

A method and device for sensing the distance between a first object and a second object so as to activate or facilitate predetermined actions when the distance has attained a certain value. A person (1) (first object) holds a handle (2) of a power tool, the handle being connected to a function generator (6) for a signal in turn connected to a unit (7) for encoding or modulating the signal. A capacitance (C1) exists between the hand of a person (1) and the handle (2). A capacitance (C2) exists between the person (1) and the active portion (4) (second object) of the tool connected to a demodulator or tone decoder (8) in turn connected to a control unit (9) incorporating the control circuitry. The control unit (9) controls the security system (10) in turn controlling the protective measures such as braking or power cut-off (11). The control unit (9) also controls an alarm and self-testing circuitry (11a).

대표청구항 ▼

[ I claim:] [1.] A method for sensing the distance between a first object and a second object being moved relative to each other and for-activating or facilitating a predetermined action or predetermined actions when said distance has attained a value including zero, the method comprising the steps

[ I claim:] [1.] A method for sensing the distance between a first object and a second object being moved relative to each other and for-activating or facilitating a predetermined action or predetermined actions when said distance has attained a value including zero, the method comprising the steps oftransmitting a capacitive proximity signal between a transmitting system and a receiving system,the first object and the second object each constituting an integral part of a respective one of the systems and a part of the signal path of the proximity signal, andthe proximity signal providing indication of distance between the first object and the second object, andmonitoring the proximity signal for sensing variations of the signal as the first object and the second object are moved relative to each other, andactivating the predetermined action when the signal has attained a predetermined condition.