Abstract: A pressure sensor includes a first substrate and a second substrate; a first driving electrode and a second driving electrode disposed on a first surface of the first substrate facing the second substrate and coupled to a first coupling electrode, the second driving electrode being shorter than the first driving electrode; a first sensing electrode and a second sensing electrode disposed on the first surface of the first substrate and coupled to a second coupling electrode, the second sensing electrode being shorter than the first sensing electrode; a first pressure sensing layer disposed on a first surface of the second substrate in a position facing the first substrate and overlapping and spaced from the first driving electrode and the first sensing electrode by a gap; and a second pressure sensing layer contacting with the second driving electrode and the second sensing electrode and electrically coupling the second driving electrode and the second sensing electrode to each other.

Abstract: An electronic device may include a conductor sensing assembly for sensing movement of a conductor, for example, in order to provide an input assembly that may be operative to detect a user's manipulation of a distance between the conductor and a portion of the conductor sensing assembly for controlling a functionality of the device. The conductor sensing assembly may include an oscillator that may produce oscillations that decay at different rates dependent upon a variable distance between a component of the conductor sensing assembly and a conductor of the input assembly. As the decay rate may be dependent on or otherwise correlate with the magnitude of a distance between the oscillator and a conductor, detection of the decay rate of the oscillator may enable determination of a state of a button input assembly that includes a conductor operative to be movable by a user with respect to the oscillator.

Abstract: According to one embodiment, a toilet seat device includes a toilet seat, and a Doppler sensor using radio waves. An opened state of the toilet seat is sensed when approach of a user to the toilet seat is sensed based on a sensing signal outputted by the Doppler sensor. It is regarded that use is in progress for urination by the user when the toilet seat is in the opened state. In a state of being regarded that use is in progress for urination, a post-use operation is performed after sensing leaving of the user from the toilet seat based on the sensing signal.

Abstract: A toilet sensor and actuator assembly, having: (a) an infrared sensor configured to detect the presence of an object at a far distance from a toilet; (b) an ultrasonic sensor configured to detect the presence of the object at a near distance from the toilet, wherein the ultrasonic sensor remains in a sleep mode until awakened by a signal from the infrared sensor that the infrared sensor has detected the presence of the object at the far distance; and (c) an actuator mechanism that flushes the toilet in response to a signal from the ultrasonic sensor that the ultrasonic sensor has detected the presence of the object at the near distance.

Abstract: An intelligent switching method and system. The method includes retrieving by a computer processor of an intelligent switching device, detection data indicating that an individual is located within a specified proximity of an apparatus. The intelligent switching device is lockably attached to the apparatus. The computer processor receives a request from an individual for enabling the apparatus. The computer processor determines that the individual is in compliance with safety procedures associated with operating the apparatus and generates an enable signal. The enable signal enables a power signal for the apparatus. The computer processor indicates that the apparatus has been enabled and is operational.

Abstract: A method and apparatus is described to detect the physical approach. The method is useful for passively detecting the presence of people, pets, or robots in proximity to a sensor. It is portable, and functions while being carried or placed inside objects.

Abstract: A smart plug for coupling an electric vehicle to a power supply includes a relay including contacts, the relay configured to operate in a closed state to enable power to be supplied to the electric vehicle and an open state to prohibit power from being supplied to the electric vehicle. The smart plug also includes a microcontroller (MCU) coupled to the relay, the microcontroller outputting a control signal to operate the relay in the closed state. The smart plug further includes a zero crossing detector (ZCD) coupled to the relay, the ZCD outputting a close signal to the relay when a voltage of the power is substantially zero and outputting an open signal to the relay when a current of the power is substantially zero.

Abstract: In one embodiment, an integrated circuit includes a pin and a current source for driving current through the pin into an external resistor such as a resistor on a circuit board to generate a pin voltage. The integrated circuit includes an analog-to-digital converter for converting the pin voltage into a digital value, such as an address for the integrated circuit.

Abstract: A redundant non-contact switch reports a status as closed or open for a first member and a second member that move relative to each other between an open state and a closed state. In some embodiments, the redundant non-contact switch includes a wireless authentication (WA) pair and a magnetic pair. The WA pair may include a WA responder attached to one of the first member and the second member, and a WA interrogator attached to the other of the first member and the second member. The WA pair may be configured to register a WA status of closed or open, depending on a WA authentication between the WA responder and the WA interrogator. The magnetic pair may include a magnet attached to one of the first member and the second member, and a magnet sensor attached to the other of the first member and the second member. The magnetic pair may be configured to register a magnetic status of closed or open, depending on whether a magnet distance between the magnet and magnet sensor is beyond a threshold magnet distance.

Abstract: An alarm system for emitting an alarm includes a distance detecting circuit, a gate circuit, a voltage conversion circuit, a distance judging circuit and an alarm circuit. The distance detecting circuit receives a first signal, detects a distance between an object and the alarm system, outputs a second signal and a third signal according to the distance. The gate circuit receives the second signal and the third signal and outputs a voltage level signal. The voltage conversion circuit receives the voltage level signal and converts the voltage level signal into a DC voltage signal. The distance judging circuit receives the DC voltage signal and compares the DC voltage signal against a reference voltage signal to output a control signal if necessary. The alarm circuit receives the control signal and produces the alarm when the distance between the object and the alarm system is less than a threshold distance.

Abstract: An electromagnetic switching apparatus includes a contact block to be inserted in an electric path, an electromagnet block for driving the contact block, the electromagnet block being configured to drive the contact block to close the electric path so as to become conductive when an excitation current is supplied from outside, a normally-closed type switch member inserted in a supply path of the excitation current, an acquisition unit configured to obtain an impact detection signal from an impact sensor that is configured to detect an impact, and a control unit configured, based on the impact detection signal obtained by the acquisition unit, to turn off the switch member so as to break the supply path when the impact sensor detects an impact of which magnitude is larger than a predetermined threshold.

Abstract: A redundant non-contact switch reports a status as closed or open for a first member and a second member that move relative to each other between an open state and a closed state. In some embodiments, the redundant non-contact switch includes a wireless authentication (WA) pair and a magnetic pair. The WA pair may include a WA responder attached to one of the first member and the second member, and a WA interrogator attached to the other of the first member and the second member. The WA pair may be configured to register a WA status of closed or open, depending on a WA authentication between the WA responder and the WA interrogator. The magnetic pair may include a magnet attached to one of the first member and the second member, and a magnet sensor attached to the other of the first member and the second member. The magnetic pair may be configured to register a magnetic status of closed or open, depending on whether a magnet distance between the magnet and magnet sensor is beyond a threshold magnet distance.

Abstract: The present invention provides an induction touch key, which comprising: a touch key unit with at least a conductor layer and an insulation layer; a first resistor electrically connected with the conductor layer; a processing unit electrically connected with the first resistor; A second resistor electrically connected with the processing unit; a switch electrically connected with the second resistor and processing unit. When the insulation layer is touched manually, the processing unit is used to detect the change of surface charge, and then output a start signal to drive the switch for an improved safety.

Abstract: A method and apparatus is described to detect the physical approach. The method is useful for passively detecting the presence of people, pets, or robots in proximity to a sensor. It is portable, and functions while being carried or placed inside objects.

Abstract: A safety switch configured to determine whether a magnetically operated switch which forms part of the safety switch has been welded closed. The safety switch is configured to establish a first magnetic field in the vicinity of the magnetically operated switch. The magnetic field is arranged to move the magnetically operated switch from a first configuration to a second configuration. The safety switch monitors the state of the magnetically operated switch to determine if the magnetically operated switch has been moved by the first magnetic field, thereby determining if the magnetically operated switch has been welded closed.

Abstract: A lighting control system comprises a plurality of toggle switches, a plurality of pushbuttons, a plurality of timer circuits, a plurality of relays, and a plurality of photocells to control a first plurality of lights, a second plurality of lights, a third plurality of lights and a fourth plurality of lights. The toggle switches and pushbuttons either control the lights directly or activate the timers to control the lights. The relays may be energized to switch on the lights. The photocells may be used to control the lights that are located in an outside setting.

Abstract: Electrically assisted safing of a solenoid linear actuator to provide shock tolerance is provided for a solenoid actuator, the actuator having an armature and at least one electromagnetic inductive coil. A controller, receiving an output from a motion sensor, adjusts an electrical power input to the electromagnetic inductive coil. When the output of the motion sensor indicates onset of an environmental transient exceeding a predetermined threshold of intensity, the controller adjusts the electrical power input such that an electromagnetic field generated by the coil is sufficient to restrain the armature in a desired position during the environmental transient.

Abstract: A method and means for controlling the operation of a machine by an operator having a transmitter mounted to a machine, a sensor attached to an operator or an operator's clothing, and a tracking device that receives signals from the sensor and determines the position of the sensor. Based on the determined position of the sensor, the tracking device sends signals to the operator and an actuator on the machine based on a comparison with a danger zone, warning zone, or operator zone.

Abstract: A contact welding detecting device includes: a relay including a first contact for permitting and breaking transmission of a first DC input potential to a first output and a second contact for permitting and breaking transmission of a second DC input potential; a relay open/close control unit that simultaneously controls to open and close the first and second contacts when welding of at least one of the first and second contacts is detected; a first potential difference detection unit that detects a potential difference between a first point at an input side of the first contact and a second point at an output side of the second contact; and a second potential difference detection unit that detects a potential difference between a third point at an output side of the first contact and a fourth point at an input side of the second contact.

Abstract: A material processing machine such as a wood chipping machine, a press, a cane cutting machine or other machine comprising an operating region having at least one processing element and an access region through which material passes to the operating region, has at least one active sensor that may be worn by a user of the machine, for example, around their wrist, and at least one detector mounted in the access region of the machine for detecting the presence of the active sensor in the access region. Control circuitry responsive to the at least one detector provides control signals for stopping operation of the machine, preventing start-up of the machine and/or otherwise preventing injury to the machine user.

Abstract: In a conventional display device comprising a sub-display, the display device is increased in thickness and in the number of components as the number of displays is increased. In the present invention, a dual emission display device is used so that either surface of a display is used as a main display or a sub-display. Accordingly, the display device can be reduced in thickness and in the number of components. Further, mechanical reliability can be enhanced when the invention is applied to a tablet PC, a video camera and the like.

Abstract: A touch switch apparatus for detecting the presence of an object such as a human appendage, the apparatus having a touch pad, an electric field generated about the touch pad and also having a preferably integrated and local control circuit connected to the touch pad and to a controlled device. The touch switch apparatus also having at least one of an input circuit portion for providing input signals to a decision circuit, swamping capacitance, active blocking devices, peak detector circuits, and a dual connection output latch circuit portion.

Abstract: In order to provide a triggering signal for a cable stripping device that is also capable of dealing with very thin wires, it is suggested to use a piezoelectric sensor, the output signal from which is forwarded to an electronic evaluation unit. The electronic evaluation unit then outputs a digital signal that enables the stripping process to be started safely. Various mechanical mechanisms are suggested to ensure that the digital signal is not triggered when not being touched. This problem is proposed to be solved by a low pass filter discriminating between sensor inputs by touching and vibration shock events, etc.

Abstract: An electric switch (1) comprising a capacity sensor circuit (2) provided with a signal input (3) arranged to be connected to an actuating line, and which is provided with a relay device (4) arranged to feed a current to a load line (7) from a power source (6) in response to a capacitive influence along said actuating line. According to the invention the signal input (3) of the sensor circuit (2) is arranged to be connected to the load line (7) in such a manner that the load line will constitute said actuating line.

Abstract: A technique for controlling a switching circuit includes one or more sensing circuits that generate signals based upon the presence of an actuating object and upon a randomly applied strobe signal. The generated signals are sampled and are used as a for determining the state of an output signal. The sensing circuit may generate the signals based upon capacitive coupling with the actuating object. The randomization of the sampling enhances immunity to periodic noise. Where more than one sensing circuit is included, the output of the circuits may be considered together for determining the state of the output signal, such as based upon predetermined ranges of signal levels. Signals of the sensing circuit may be sampled in the absence of the strobe to provide an indication of the relative noise level. If the noise level is determined to be elevated, the output signal may not change states.

Abstract: In a method for function monitoring of an electronic-mechanical position switch in which the wiper voltage of a potentiometer acted upon by an actuation tappet is evaluated in comparison to a threshold value in order to activate or deactivate electronic contacts, during first or second test intervals a microcontroller interrupts watchdog signals or contact-closing control signals and checks the state of the switching contacts. If the expected state transition of the switching contacts from the closed into the open state does not occur, then the control signals make the transition to the contact-opening signal level or the watchdog signals are discontinued.

Abstract: Some embodiments provide a sensor element, a shield element capacitively coupled to the sensor element and to ground, a coupling circuit to receive an input signal, and to electrically couple the received input signal to the sensor element and to the shield element, an output circuit to generate an output signal, the output signal based on a capacitance between the sensor element and an object, and a classifier to determine a material based on the output signal, and to transmit a material signal to the output circuit based on the determined material, wherein the output circuit is adjustable based on the material signal.

Abstract: A system and method for detecting user entry into a defined danger zone surrounding a saw blade includes a non-conducting member defining an opening therein for receiving a saw blade. The non-conducting member may comprise, for example, an insert received by an opening in the work surface or table of a table saw, scroll saw, band saw, miter saw, etc. Alternatively, it may comprise the blade guard of a radial arm saw or miter saw, for example. A conductive sensor is situated on the non-conducting member adjacent the opening to define a danger zone near the saw blade. A voltage source is coupled to the sensor, and a monitor circuit is configured to detect a change in the sensor's capacitance so as to signal a user entry into the danger zone.

Abstract: A glass touch sensing circuit which is capable of accurately detecting a sense signal resulting from a user's touch under no influence of variations in temperature. The glass touch sensing circuit is adapted to compare the level of an output signal from a switching device, which indicates whether the user touches a touch sensor, with that of a reference signal and convert the output signal from the switching device into a wave-shaped signal in accordance with the compared result. The present glass touch sensing circuit is further adapted to determine the level of the reference signal for compensation for a variation in the output signal from the switching device with temperature. Therefore, the glass touch sensing circuit can be employed in a human body touch-based key input sensing system to provide a constant performance irrespective of a variation in temperature so as to sense a key input based on a touching operation.

Abstract: A material processing machine such as a wood chipping machine, a press, or other machine comprising an operating region having at least one processing element, and an access region through which material passes to the operating region, has at least one passive sensor that may be worn by a user of the machine, for example, around their wrist, and at least one sensing coil mounted in the access region of the machine for detecting the presence of the passive sensor in the access region. Control circuitry responsive to the at least one sensing coil provides control signals for stopping operation of the machine, preventing start-up of the machine and/or otherwise preventing injury to the machine user.

Abstract: A collision avoidance system for sensing a presence of objects within a critical distance is provided. The system comprises a collision avoidance array disposed on a face of the system component, the collision avoidance array comprising a plurality of plates configured to detect a presence of objects and generate a corresponding electrical signal. In addition, the system further comprises a multiplexer configured to selectively couple the plurality of plates to a sensing circuit. The sensing circuit configured to sense the electrical signal and generate a corresponding electric field around the collision avoidance array to prevent the object from colliding with the system sub-component.

Abstract: The system includes a unipolar A/D converter, which samples analog signal inputs thereto, the A/D converter being used in a protective relay for electric power systems. The unipolar A/D converter is responsive to input voltage values and current values from the power line to produce corresponding digital signals. The A/D converter has a ground pin voltage reference at least as negative as the most negative point of the input signal to be processed.

Abstract: Electrostatic discharge (ESD) event early warning systems and methods that provide a precursor warning signal to a system that is to be protected and implements electrostatic discharge event prediction and countermeasure using charge proximity sensing. The relatively slow approach of a charged object to the system that is to be protected is sensed prior to actual discharge. In one embodiment, charge is actively switched to a guard structure designed to protect sensitive exposed circuitry of the system that is to be protected. In addition, a proximity sense signal may be used within the system that is to be protected to save data that is processed by the system, start ESD countermeasures within the system switch off sensitive subsystems of the system, or switch on grounding relays within the system.

Abstract: An alarm system and method is provided for preventing injuries as may occur within a manufacturing plant using lathes, milling equipment, metal shears and other machinery. The alarm system is so positioned to allow safe operation of the machinery while tracking the operator's movement. A transmitter attached to the operator's hand allows monitoring of the operator and prevents unsafe actuation of the machinery. The alarm system can also be programmed to prevent operation by unauthorized personnel and includes a trio of X, Y and Z spatially positioned receivers which are connected to a programmed system controller to activate alarms or to terminate power to the machinery.

Abstract: A relay adhesion detecting device (10) of the invention is installed in an electric motor vehicle wherein a relay (14) is provided between a power source unit (12) comprising a plurality of secondary batteries and a load circuit including an electric motor for effecting or interrupting the supply of current from the power supply unit (12) to the load circuit. The device (10) comprises one secondary battery (12a) included among the batteries of the power source unit (12), the relay (14), an adhesion detecting circuit (16) and a CPU (31). The CPU (31) detects adhesion in the relay (14) due to melting by detecting the presence or absence of current flowing through a closed loop circuit comprising the secondary battery (12a), the relay (14) and the adhesion detecting circuit (16).

Abstract: A proximity switch is described, specifically a capacitive proximity switch, with two signal transmitters (1, 2) and with one signal receiver (3), a first signal output (4, 5) of each of the two signal transmitters (1, 2) being connected to one another and to a first signal input (6) of the signal receiver (3), and a second signal output (7, 8) of each of the two signal transmitters (1, 2) being connected via a respective signal transmission path (9, 10) to a second signal input (11) of the signal receiver (3), and at least one of the two signal transmission paths (9, 10) can be influenceable by an actuating object.

Abstract: A fingerprint identification device judges that the input fingerprint is identical to the fingerprint in the database only when a the touch sensor detects the human finger and a the fingerprint processing unit detects that the input fingerprint is identical to a fingerprint in the database. The touch sensor includes an oscillator that outputs a high frequency signal. An electrode unit applies the high frequency signal to the human finger. A detector unit detects a variation of impedance values varied by the human finger contracting the electrode unit and outputs an output signal based on the variation of impedance values. A discriminator unit determines whether the human finger is in contact with the electrode unit by comparing the output signal from the detector unit with a predetermined reference value.

Abstract: A relay adhesion detecting device (10) of the invention is installed in an electric motor vehicle wherein a relay (14) is provided between a power source unit (12) comprising a plurality of secondary batteries and a load circuit including an electric motor for effecting or interrupting the supply of current from the power supply unit (12) to the load circuit. The device (10) comprises one secondary battery (12a) included among the batteries of the power source unit (12), the relay (14), an adhesion detecting circuit (16) and a CPU (31). The CPU (31) detects adhesion in the relay (14) due to melting by detecting the presence or absence of current flowing through a closed loop circuit comprising the secondary battery (12a), the relay (14) and the adhesion detecting circuit (16).

Abstract: A material processing machine such as a wood chipping machine, a press, or other machine comprising an operating region having at least one processing element, and an access region through which material passes to the operating region, has at least one passive sensor that may be worn by a user of the machine, for example, around their wrist, and at least one sensing coil mounted in the access region of the machine for detecting the presence of the passive sensor in the access region. Control circuitry responsive to the at least one sensing coil provides control signals for stopping operation of the machine, preventing start-up of the machine and/or otherwise preventing injury to the machine user.

Abstract: An important consideration in making a fiber optic device (e.g., comprising fiber in a polished tube at a certain angle and GRIN lens) is to limit sense, maintain and/or measure the gap-width between these two polished surfaces before they are either fused or glued for optimum performance. In automating the configuration, the gap is sensed, apart from optimizing in the transverse plane to minimize the loss. In the present application, a limit sensing method and system is provided to improve the effectiveness in automated manufacturing systems, by exploiting the electromechanical properties of induced EMF (Electro-Magnetic Force) by an electrical coil in presence of a magnet at mechanical resonance. Once it is known when two optical surfaces to be glued are said to have zero gap (i.e., contact between the surfaces), the present system provides an annunciation from limit-sensing electronics.

Abstract: An automatic shut-off and indication device for an electric heating appliance is provided which includes: a sensor (2) for sensing usage of the appliance and for providing a usage-signal (US) indicating a non-usage of the appliance; a switch (10) for off-switching a heater (12) of the appliance in response to a switching signal (SS) derived from the usage-signal (US); a sensor (4) for sensing orientation of the appliance and for providing an orientation signal (OS) for indicating different orientations of the appliance; a selector (18) for activating an indicator (22) in response to the switching signal (SS), the indicator (22) signaling the off-switching of the heater (12); and an indication timer (8) for providing a time delay between off-switching the heater (12) and activating the indicator (22), which time delay is dependent on the orientation signal (OS). The shut-off of the heater (12) is signalled to the user by the indicator (22).

Abstract: An electronic device (1), e.g. a mobile telephone having a front cover (6) and a capacitive proximity sensor, comprising: a first electrode (9; 27) and a second electrode (8; 21, 20), said first electrode having a large face (11, 12, 13; 29); and detector means connected to the first electrode (9, 27) and the second electrode (8, 21, 20) for detecting the capacitance of the first electrode relatively to the second electrode and for providing a control signal (Vprox) responsive to the capacitance. The large face (11, 12, 13; 29) of the first electrode is inclined relative to the front cover (6).

Abstract: A safety system for a machine such as a wood chipping machine. The safety system has a passive sensor that may be worn on the machine operator's wrist, a sensing coil mounted to a feed chute of the machine for detecting the proximity of the passive sensor, and control circuitry which is responsive to the sensing coil. The circuitry provides a control signal for use in stopping operation of the machine. In use, the presence of the operator's arm in the chute near to parts of the machine that can cause injury will trigger the sensing coil and cause the machine to cease operating, thus circumventing injury to the operator.

Abstract: A flat panel display device including a panel unit for displaying an image, a main body unit controlling an image displayed on the panel unit, and a folder connecting the panel unit and the main body unit.

Abstract: A battery powered radio programmable remote switch controller and a separate hand held programming unit (programmer) designed to conserve the life of the life of the controller batteries using a combination of low voltage circuitry in the controller and a magnetic switch in the controller that is triggered by the programmer. When brought into proximity with the controller, a magnet in the programmer activates a magnetic switch in the controller which energizes a radio receiver in the controller to receive programming transmitted by the programmer. After downloading the program, removal of the programmer from the proximity of the controller deactivates the magnetic switch turning off the radio receiver, thereby saving over 99% of the power otherwise required to continuously monitor for a radio signal.

Abstract: A vehicular input device is disclosed which can afford a high stability of movable portions and an excellent power saving characteristic without impairing the operability of a manual operating unit. A mechanical portion of the vehicular input device is provided with a spherical bearing, a pivot shaft supported pivotably by the spherical bearing, a solenoid disposed below the spherical bearing, and a clamp member for clamping the pivot shaft, the clamp member being secured to an upper end portion of a drive shaft of the solenoid. A lower end portion of the pivot shaft is formed in a conical shape which becomes smaller in diameter gradually downwards. In an upper surface of the clamp member which is opposed to the lower end portion of the pivot shaft there is formed a generally conical depression into which the lower end portion of the pivot shaft can be inserted.

Abstract: A battery powered radio programmable remote switch controller and a separate hand held programming unit (programmer) designed to conserve the life of the life of the controller batteries using a combination of low voltage circuitry in the controller and a magnetic switch in the controller that is triggered by the programmer. When brought into proximity with the controller, a magnet in the programmer activates a magnetic switch in the controller which energizes a radio receiver in the controller to receive programming transmitted by the programmer. After downloading the program, removal of the programmer from the proximity of the controller deactivates the magnetic switch turning off the radio receiver, thereby saving over 99% of the power otherwise required to continuously monitor for a radio signal.

Abstract: A control mat monitoring and warning apparatus and method in which the resistance of a control mat is monitored continuously while the mat remains in use. Deviations of the pattern of control mat resistance values in use from a nominal range of acceptable values is used to detect and report deterioration of the electrical performance characteristics of the control mat so that the mat can be removed from service and replaced in a timely manner. The disclosed invention also generates proper presence detection signals by compensating for the deteriorating electrical performance characteristics of the control mat, thereby extending the useful functional life of the control mat beyond the point at which the mat could otherwise function properly.

Abstract: A device is provided for allowing detection of a switch closure across an air gap between components. The device comprises a wireless inductive coupled switch designed for use with any suitable proximity sensor. The switch and sensor transmit a switch closure at a closable switch across the air gap. When the wireless inductive coupled switch is moved into the sensing range of the inductive proximity sensor, the ferrite core portion of the inductive coupled switch and the coil surrounding the ferrite portion are inductively coupled by the alternating field generated by the inductive proximity sensor. The alternating magnetic flux lines of the inductive proximity sensor move back and forth through the ferrite core portion and the coil. As long as the closable switch is open, no current is induced into the coil.

Abstract: The invention relates to a contactless safety switch for detecting the shut position of a shutting part in relation to a closeable part, with a switch unit, supplied with current by an electrical supply source on one of the parts and with a trip arranged on the other part and comprising a magnet. In this case, the switch unit comprises a transmission circuit with a clock-signal generator and with a transmission coil, a receiver circuit connected to an evaluation unit and having at least one receiver coil and also a Hall sensor responding to the magnet, and the trip comprises a trip coil which is capable, in the shut position, of being excited inductively by the transmission coil and exciting the receiver coil, while, in the shut position, the evaluation unit triggers a clearance path when the Hall sensor is activated via the magnet.