System and method of connecting multiple safety light curtains
First Claim
Patent Images
1. A light screen safety system comprising:
- a plurality of light screens including a master light screen and at least one other light screen, the at least one other light screen operably connected and arranged sequentially upstream from the master light screen, each light screen including at least one processor, an emitter with a plurality of light transmitters, and a receiver with a plurality of light detectors, each light transmitter paired with one light detector;
a control unit operably connected to and downstream from the master light screen;
the processor of each light screen configured to determine if a light signal transmitted by any of the light transmitters is blocked from being received by the paired detector;
the processor of the at least one other light screen configured to send a stop signal to the master light screen when a blocked condition is detected; and
the processor of the master light screen transmitting the stop signal to the control unit when the master light screen receives the stop signal from an adjacent upstream light screen.
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Abstract
A light screen safety curtain system including multiple light screens cascaded together to cooperatively protect an area or machine against unwanted intrusion. Such a system includes a plurality of independently operating light screens electrically connected to each other and to a control unit. When any one light screen detects an unwanted intrusion through a guarded opening, a stop or warning signal is generated by that light screen and is transmitted to the control unit. A method of configuring a light screen safety system without the need for an external programming device is provided.
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Citations
24 Claims
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1. A light screen safety system comprising:
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a plurality of light screens including a master light screen and at least one other light screen, the at least one other light screen operably connected and arranged sequentially upstream from the master light screen, each light screen including at least one processor, an emitter with a plurality of light transmitters, and a receiver with a plurality of light detectors, each light transmitter paired with one light detector; a control unit operably connected to and downstream from the master light screen; the processor of each light screen configured to determine if a light signal transmitted by any of the light transmitters is blocked from being received by the paired detector; the processor of the at least one other light screen configured to send a stop signal to the master light screen when a blocked condition is detected; and the processor of the master light screen transmitting the stop signal to the control unit when the master light screen receives the stop signal from an adjacent upstream light screen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 20, 21, 22)
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13. A method of programming a light screen safety system, the light screen safety system comprising a master light screen electrically connected to a control unit and at least a first upstream light screen, each light screen including a plurality of light transmitters, a plurality of light detectors, and on-board circuitry including a microprocessor and memory, the method comprising:
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placing the master light screen of the light screen safety system into a configuration mode, the master light screen signaling any upstream light screens to initiate configuration by sending a polling signal to the first upstream light screen; after each upstream screen receives the polling signal, initiating a configuration mode of the upstream light screen, and resending the polling signal upstream until all upstream light screens have been signaled to initiate configuration mode; sending a query signal from the master light screen to the first upstream light screen; after the on-board circuitry of the first upstream light screen receives the query signal, sending a response signal downstream to the master light screen, and retransmitting the query signal to any next upstream light screen; after the on-board circuitry of each light screen receives the query signal and sends a response signal downstream, and any intermediate light screens retransmit the response signal received from any upstream light screens downstream to any next downstream light screen, the on-board circuitry of the master screen determining the configuration of the light screen safety system from the received response signals and storing the configuration information of the light screen safety system in the on-board circuitry of the master light screen. - View Dependent Claims (14, 15)
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16. A method of using a light screen safety system comprising:
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providing a light screen safety system comprising; (a) a plurality of light screens including a master light screen and at least one other light screen, the at least one other light screen operably connected and arranged sequentially upstream from the master light screen, each light screen including at least one processor, an emitter with a plurality of light transmitters, and a receiver with a plurality of light detectors, each light transmitter paired with one light detector; and (b) a control unit operably connected to and downstream from the master light screen; determining at each light screen whether a light signal transmitted by any of the light transmitters of the screen is blocked from being received by the paired detector; sending a stop signal from the at least one other light screen to the master light screen when a blocked condition is detected; and transmitting the stop signal to the control unit when the master light screen receives the stop signal from an adjacent upstream light screen. - View Dependent Claims (17, 18, 23, 24)
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19. A light screen safety system comprising:
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a plurality of units operably connected and arranged sequentially with respect to each other from a first unit to a last unit, each of the units comprising at least one processor, the plurality of units including a plurality of light screens and at least one control unit, each light screen comprising an emitter with a plurality of light transmitters, and a receiver with a plurality of light detectors, each of the light transmitters being paired with one of the light detectors; the processor of each light screen being configured to determine whether a light signal transmitted by any of the light transmitters of the light screen is blocked from being received by the paired detector; each light screen being configured to send a stop signal to a next adjacent downstream one of the units when a blocked condition is detected by the light screen; the processor of each unit being configured to transmit a stop signal to a next adjacent downstream one of the units if the processor receives the stop signal from a next adjacent upstream one of to units until the last unit receives the stop signal; and the plurality of light screens including a master light screens the processor of the master light screen being configured to transmit a stop signal to the control unit when the master light screen receives a stop signal from an adjacent upstream unit.
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Specification