US3875403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light beam apparatus
Assignee: Individual
•
Filing: 1974-02-27
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Granted: 1975-04-01
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Expires: 1994-02-27
Abstract
Abstract A light curtain for supervising or controlling the operation of machines comprising a series of electrical light sources arranged to give light pulses which are short in relation to the repetition frequency. After the light pulses have spanned the supervised region they are detected by one or more pulse detectors for each light source. When the detectors associated with each light source receive simultaneous pulses on their inputs a starting pulse for the light source next in sequence in the series is released.
Inventors
- 👤 Lars Erik Svensson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:59
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/12; F16P3/14; F16P3/144
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
119 words
A light curtain apparatus for supervising and/or operation of machines, comprising a series of electrical light sources (3) arranged to give, through a periodic pulse source (1) light pulses which are short in relation to the repetition frequency of the pulse source, said light pulses after having spanned the opening in the light curtain being detected by one or more light pulse detectors (5) arranged for each light source (3), wherein the light detectors (5) for each light source control a pulse control circuit (6) which, on receiving essentially simultaneous pulses on its inputs, releases a starting pulse for the light source (7) next in sequence in the series, and simultaneously gives a supervisory circuit (12) an acknowledgement pulse.
Claim 2
Dependent Claim
119 words
A light curtain apparatus for supervising and/or operation of machines, comprising a series of electrical light sources (3) arranged to give, through a periodic pulse source (1) light pulses which are short in relation to the repetition frequency of the pulse source, said light pulses after having spanned the opening in the light curtain being detected by one or more light pulse detectors (5) arranged for each light source (3), wherein the light detectors (5) for each light source control a pulse control circuit (6) which, on receiving essentially simultaneous pulses on its inputs, releases a starting pulse for the light source (7) next in sequence in the series, and simultaneously gives a supervisory circuit (12) an acknowledgement pulse.
Claim 3
Dependent Claim
30 words
A light curtain apparatus according to claim 1, wherein the starting pulse for each light source is also arranged to feed an input of the respective pulse control circuits (6,11,16,20).
Claim 4
Dependent Claim
46 words
A light curtain apparatus according to claim 1 wherein at least two supervisory circuits (12,21) are arranged, each having a number of inputs corresponding to half the number of light source circuits (2-6, 13-16, etc.), each input being connected to an appropriate pulse control circuit (6,16).
Claim 5
Dependent Claim
30 words
A light curtain apparatus according to claim 3 wherein alternate pulse control circuits (6,16 and 11,20 respectively) are connected to one and the same supervisory circuit (12 and 21 respectively).
Claim 6
Dependent Claim
36 words
A light curtain apparatus according claim 1 wherein each of the supervisory circuits (12 and 21 respectively) controls its own operating circuit (22 and 23 respectively) for the machine which is to be supervised and/or operated.
Claim 7
Dependent Claim
32 words
A light curtain apparatus according to claim 5 wherein the operating circuits comprise relays (22,23) the contacts of which are co-actively arranged to control the controlling circuits of the machine in question.
Claim 8
Dependent Claim
32 words
An apparatus according claim 1 wherein each pulse control circuit (6) contains a time delay means, a pulse being taken off said time delay means to feed the appropriate supervisory circuit (12).
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |