APERTURE CLOSURE MEMBER CONTROL ARRANGEMENTS
4 Assignments
0 Petitions
Accused Products
Abstract
An aperture closure member control arrangement includes a disc which rotates as the aperture closure member moves. The disc has a ring of teeth. A sensor, such as a Hall effect sensor and permanent magnet, detect the passage of teeth as a cyclic waveform of amplitude and frequency determined by the spacing of the teeth, and the speed of rotation of the disc. An irregularity in the form of a missing tooth creates an irregularity in the output of the sensor, in the form of a pulse of greater amplitude and lower frequency. Accordingly, pulses from the irregularity can be discriminated and counted to provide a coarse indication of position, or pulses from the teeth can be counted, to provide a fine indication.
7 Citations
96 Claims
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1-53. -53. (canceled)
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54. An aperture closure member control arrangement, comprising:
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a pulse generator operable to create a train of pulses as the aperture closure member moves; a counter operable to count pulses of the train to provide an indication of the position of the aperture closure member; wherein the pulse generator creates first type pulses and less frequent second type pulses, and wherein the arrangement further includes a discriminator operable to discriminate between first and second type pulses, for providing a count based selectively on first or second type pulses. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63)
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64. An aperture closure member control arrangement comprising:
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a rotatable member which rotates as the aperture closure member moves; a sensor; a ring of features on the rotatable member and able to be sensed by passing the sensor to create a train of first type pulses; wherein the ring of features includes an irregularity at least one position, to create a second type pulse within the train. - View Dependent Claims (65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77)
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78. An aperture closure member control arrangement comprising:
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a control circuit operable to provide electrical power to a motor to drive the aperture closure member, when required; a current supply powered from the motor supply to return a signal current to the control circuit; and a sensor operable to modulate the signal current in accordance with movement of the aperture closure member, for sensing at the control circuit. - View Dependent Claims (79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96)
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Specification