Abstract: A vibration sensor (5) mountable to a wind turbine generator for detecting excessive vibration of the wind turbine generator, the sensor comprising a pendulum having a pendulum bob (25) of pre-determined mass coupled to a detection switch (10), the detection switch arranged to detect oscillation of the pendulum exceeding a predetermined oscillation threshold; said pendulum bob selectively adjustable along said pendulum so as to vary the oscillation threshold of said sensor; wherein the sensor is arranged to exceed the oscillation threshold on receiving a forced vibration corresponding to a vibration threshold of the wind turbine generator.

Abstract: Timepiece including a clockwork movement (2) provided with an analogue display (14). The wheel (4) includes a plate (8) with a toothing (6) defined by its external edge and a shaft (10). A device for detecting the angular position of the wheel (4) includes a magnetic or capacitive sensor (20) whose detection element, in particular a flat spiral coil (24), is used for detecting a variation in presence of the material, in particular a non magnetic conductive metal, forming the plate (8). The plate has at least one opening (16) situated in the intermediate region thereof between a central hole (18), and the tooth (6). The opening (16) defines a reference geometric semi-axis of the wheel (4) whose angular position is determined by the detection device provided.

Abstract: An electromagnetic drive circuit comprises a coil for detecting and driving a permanent magnet; a comparator for generating an output when the induced voltage of the coil exceeds a reference voltage; a pulse generator for generating a drive pulse train in response to generation of the output of the comparator; a driver responsive to the drive pulse train for feeding a drive current to the coil; and a controller responsive to interruption of the output of the comparator for interrupting generation of the drive pulse train of the pulse generator. The permanent magnet is detected and driven by the single coil so that the output may be generated by the comparator when the induced voltage of the coil exceeds the reference value, and the drive pulse train is generated during generation of that output to feed the drive current to the coil. The coil can always be efficiently driven at the maximal point of the induced voltage, and the permanent magnet can be driven with a stable amplitude.

Abstract: Herein disclosed is an electromagnetic drive circuit for driving a pendulum or the like, comprising: a coil for detecting and driving a permanent magnet; a reference voltage source having a variable reference voltage; a comparator for generating an output when the induced voltage of the coil exceeds the reference voltage; a pulse generator for generating a drive pulse in response to generation of the output of the comparator; a driver responsive to the drive pulse for feeding a drive current to the coil; and a controller responsive to the output of the comparator for controlling the reference voltage in accordance with the amplitude of the induced voltage. It is possible to integrate the most of construction and to eliminate the disadvantage of generating the drive pulses at the level of the induced voltage other than its maximal point so that the automatic control can be accomplished to effect the drive efficiently at the maximal point of the induced voltage at all times.

Abstract: A braking device is provided to reduce the speed at which a shiftable spring motor runs down. The braking device includes a pallet which is mounted so that it can oscillate, the pallet having a pair or arms which cooperate with the teeth of an escape wheel 13 which rotates as the spring runs down. The pallet is connected to a pendulum weight. The depth of engagement of the arms of the pallet in the teeth of the escape wheel as well as the amplitude of oscillation of the pallet and/or the pendulum weight connected therewith allow the braking action to be changed and hence the speed at which the motor runs down in one of a plurality of selectable shift positions.

Abstract: An electromagnetic driving circuit for driving a pendulum comprises a coil for detecting and driving a permanent magnet, a comparison circuit for comparing an induction voltage induced in the coil with a reference voltage, a generating circuit for generating driving pulses of a predetermined pulse width in response to outputs of the comparison circuit, and a driving circuit for flowing a driving current through the coil in accordance with the driving pulses. The timing at which the driving pulses are generated and/or the pulse width of the driving pulses are automatically adjusted to optimum values to improve the driving efficiency of the pendulum.

Abstract: A pendulum has a weight suspended from a bar at an essentially frictionless pivot near the center of gravity of the weight.

Abstract: In an electronic timepiece having a primary frequency divider circuit coupled to receive a standard frequency signal and comprising a group of P-channel FETs and a group of N-channel FETs, a bias circuit supplies a bias input to the P-channel FET group and a separate bias input to the N-channel FET group. By providing these bias inputs through current mirror coupling from a standard current source, the response of the primary frequency divider circuit to low amplitudes of the standard frequency signal can be made substantially independent of timepiece battery voltage variations, over a wide range of battery voltages.

Abstract: A method and apparatus for accurately controlling a timekeeping apparatus utilizing a relatively heavy free pendulum or other harmonic structure carrying a permanent magnet, and a powered harmonic structure carrying a ferromagnetic element. The magnet is positioned on its carrier in a manner to effect energy transfer between the pendulums or structures during intermittent periods of magnetic attraction as the two structures oscillate. The free structure governs the speed of oscillation of the powered structure to maintain accurate control over the latter and energy transferred from the powered structure to the free structure maintains continued oscillation of the governing, free structure.

Abstract: A mechanically operating pendulum clock is provided with an electronic cocting device which comprises a quartz oscillator. An electronic frequency divider generates from the oscillation frequency of the quartz oscillator a frequency equal to that of the pendulum. A permanent magnet is arranged on the pendulum to cooperate with a control coil forming an electro-mechanical converter. The control coil is effective at least in the two turning positions of the pendulum. A contact-free pendulum sensor is also provided. A proportional electronic control device includes a converter which produces rectangular signals from the signals emitted by the quartz oscillator and the sensor, and a comparator is adapted, depending upon the reciprocal phase position of the quartz oscillator and sensor signals to transmit delay or acceleration signals to the control coil as well as opposing acceleration or delay signals to the control coil but phase-shifted by 180.degree..