US3798517A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera lens control mechanism
Assignee: Rank Organization Ltd
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Filing: 1971-12-22
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Granted: 1974-03-19
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Expires: 1991-12-22
Abstract
Abstract The invention concerns a control module for attaching to a lens and including an actuator and a feedback path, the actuator driving the controlled lens element through a slipping clutch. The invention provides switch means on the module for injecting fixed signals into the feedback system to drive the actuator to either end of the travel of the controlled element to align same with a feedback device (e.g. a potentiometer) on setting up the module on the lens.
Inventors
- 👤 J Whitehouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:09
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/02; G02B7/04; G02B7/08; G03; G03B; G03B17/00; G03B17/02; G03B17/12; G03B17/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
233 words
A lens control module comprising a housing attachable to a camera, which camera is equipped with a demand unit and has a lens element movable between extreme positions, said housing containing an actuator (6) for moving the lens element, control means (2) driven by said actuator for movement between extreme positions in unison with the movement of the lens, which control means produces a feedback signal representing the position of the actuator and hence of the lens element, means (20) for producing an error signal representing the difference between a demand signal from said demand unit and said feedback signal, an amplifier (3) connected to control the actuator in response to said error signal, and a slipping clutch (8) connected between said actuator and said control means so that when said control means reaches one of said extreme positions before the lens reaches the corresponding extreme position said clutch slips and said actuator may continue to drive said lens element until the lens element also reaches a corresponding extreme position in alignment with said control means, and switch means (14, 15) accessible from outside said housing and operable to selectively apply a predetermined signal to the actuator which causes said actuator to drive at least one of said lens element and control means until they are brought into alignment in corresponding extreme positions, said module being detachable as a unit from said camera.
Claim 2
Dependent Claim
233 words
A lens control module comprising a housing attachable to a camera, which camera is equipped with a demand unit and has a lens element movable between extreme positions, said housing containing an actuator (6) for moving the lens element, control means (2) driven by said actuator for movement between extreme positions in unison with the movement of the lens, which control means produces a feedback signal representing the position of the actuator and hence of the lens element, means (20) for producing an error signal representing the difference between a demand signal from said demand unit and said feedback signal, an amplifier (3) connected to control the actuator in response to said error signal, and a slipping clutch (8) connected between said actuator and said control means so that when said control means reaches one of said extreme positions before the lens reaches the corresponding extreme position said clutch slips and said actuator may continue to drive said lens element until the lens element also reaches a corresponding extreme position in alignment with said control means, and switch means (14, 15) accessible from outside said housing and operable to selectively apply a predetermined signal to the actuator which causes said actuator to drive at least one of said lens element and control means until they are brought into alignment in corresponding extreme positions, said module being detachable as a unit from said camera.
Claim 3
Dependent Claim
29 words
A module as claimed in claim 8, in which the switch means applies another predetermined signal to the amplifier which in turn applies said predetermined signal to the actuator.
Claim 4
Dependent Claim
35 words
A module as claimed in claim 8, in which the switch means comprises a first and a second switch arranged to connect the amplifier input to a fixed positive and a fixed negative voltage respectively.
Claim 5
Dependent Claim
21 words
A module as claimed in claim 3, in which said fixed voltages are of greater magnitude than the maximum error signal.
Claim 6
Dependent Claim
27 words
A module as claimed in claim 2, in which closing of either switch opens a further switch to cut off the error signal from the amplifier input.
Claim 7
Dependent Claim
54 words
A module as claimed in claim 2, further including a tachogenerator driven by the actuator for supplying a signal representing the actuator velocity, and a comparator arranged between the switch means and the amplifier, and connected to receive said signal representing the actuator velocity whereby movement of the actuator is subject to velocity damping.
Claim 8
Dependent Claim
74 words
A module as claimed in claim 8, in which the switch means comprises a first multiple switch arranged on actuation to connect the actuator to a voltage supply for moVement in one direction and to disconnect the actuator from the amplifier, and a second multiple switch arranged on actuation to connect the actuator to the voltage supply in opposite polarity for movement in the reverse direction and to disconnect the actuator from the amplifier.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |