Safety switch light fence

• US 4,840,248 A
• Filed: 06/02/1987
• Issued: 06/20/1989
• Est. Priority Date: 06/02/1987
• Status: Expired due to Fees

• Current Assignee: Edward J. Silverman
• Original Assignee: Edward J. Silverman
• Inventors: Silverman, Edward J.
• Primary Examiner(s): Bertsch, Richard A.
• Application Number:
  US07/057,095
• Time in Patent Office: 749 Days
• Field of Search: 180/271, 180/272, 180/273, 180/274, 180/275, 250/221
• US Class Current: 180/272
• CPC Class Codes: B60G 2300/022 Fork lift trucks, Clark
• CPC Class Codes: B60K 28/04 responsive to presence or absence of the driver, e.g. to weight or lack thereof
• CPC Class Codes: B66F 17/003 for fork-lift trucks

Abstract

A safety switch light fence for vehicles such as fork lift trucks has a photoelectric cell system positioned across a vehicle exit opening in an area where an operater'"'"'s foot is disposed when the operator allows his foot to protrude from the cab. At least one of a signaling device and an automatic cut-off are activated when protrusion of an operator'"'"'s leg or foot is sensed. One or more light beams are directed across the exit opening. A foot switch can be used to sense proper placement of the operator'"'"'s feet in the cab and to disable the photoelectric cell system, alarm and/or cut-off if the feet are safely stowed.

Claims

1. In a vehicle having multiple exit openings about an operator station from which an operator controllably operates various functions of the vehicle, the improvement comprising:

a photoelectric cell system disposed substantially across said multiple exit openings about the operator station, including at least one light source and a plurality of light sensors spaced from the light source, the light sensors producing respective signals responsive to obstruction of a respective beam adjacent the corresponding exit opening from the source to the respective sensor, and means responsive to the respective signal for operating at least one of an indicator and a device for disabling of the vehicles.

2. The vehicle of claim 1, wherein the vehicle is a fork lift truck.

3. The vehicle of claim 1, wherein the photoelectric cell system comprises at least one of a plurality of light sources and a plurality of the light sensors, arranged to define a plurality of beams at the exit opening.

4. The vehicle of claim 3 further comprising a beam splitter, the photoelectric cell system having at least one light source and at least two light sensors, a beam emitted from the at least one light source being split by the beam splitter into spaced beams directed to the at least two light sensors, obstruction of either of the spaced beams being operable to activate said means responsive to the signal.

5. The vehicle of claim 1 wherein said photoelectric cell system produces an electrical output signal when an object breaks the beam between the light source and the light sensor, and further comprising an audio means activated by said output signal.

6. The vehicle of claim 5 wherein said light is visible.

7. The vehicle of claim 5 wherein said light is invisible.

8. The vehicle of claim 1 wherein the source and the sensor are on facing portions of the exit opening and the beam is disposed in the exit opening, the beam including a substantially horizontal light beam.

9. The vehicle of claim 8 wherein the beam also includes a diagonal light beam.

10. The vehicle of claim 1, wherein the beam extends adjacent the exit opening at a space from a wall of the vehicle.

11. The vehicle of claim 10, wherein the light source and the light sensor are mounted on an external surface of the vehicle adjacent the exit opening.

12. The vehicle of claim 1 further comprising a switch means disposed in a floor of the vehicle at the operator'"'"'s station, the switch means being connected to the photoelectric system, and the switch means disabling operation of said photoelectric system when at least one of an operator'"'"'s feet are disposed on the switch means.

13. The vehicle of claim 12 wherein the switch means comprises at least two switches connected to one another and spaced for operation by both of the operator'"'"'s feet.

14. The vehicle of claim 12, wherein said switch means is open when both of the operator'"'"'s feet are on the cab floor and the vehicle is operational.

15. The vehicle of claim 1 further comprising a vehicle operation cut-off means responsive to said photoelectric cell system and operable to positively deactivate the vehicle when the beam is broken.

16. The vehicle of claim 15,wherein the cut-off means include a brake adaped to positively stop vehicle movement.

17. The vehicle of claim 15 including audio alarm means operative upon said breaking of the beam.

18. The vehicle of claim 1, wherein the beam is positioned to be obstructed by an operator'"'"'s foot protruding through the exit opening as the operator sits in place in the operator station.

19. In a vehicle having an operator station from which an operator controllably operates various functions of the vehicle, the improvement comprising:

a photoelectric cell system disposed substantially across an exit opening from the operator station, including a light source and at least two light sensors spaced from the light source, a beam splitter disposed such that a beam emitted from the light source is split by the beam splitter into spaced beams directed to the at least two light sensors, the light sensors producing a signal responsive to obstruction of either of the spaced beams adjacent the exit opening, and means responsive to the signal for operating at least one of an indicator and a device for disabling of the vehicle.

20. In a vehicle having an operator station from which an operator controllably operates various functions of the vehicle, the improvement comprising:

a photoelectric cell system disposed substantially across an exit opening from the operator station, including a light source and a light sensor spaced from the light source, the light sensor producing a signal responsive to obstruction of a beam adjacent the exit opening from the source to the sensor, means responsive to the signal for operating at least one of an indicator and a device for disabling of the vehicle; and

a switch means disposed in a floor of the vehicle at the operator'"'"'s station, the switch means being connected to the photoelectric system, and the switch means disabling operation of said photoelectric system when at least one of an operator'"'"'s feet are disposed on the switch means.