Automatic guided vehicle safety system

• US 4,802,548 A
• Filed: 12/21/1987
• Issued: 02/07/1989
• Est. Priority Date: 12/21/1987
• Status: Expired due to Fees

• Current Assignee: Munck Automation Technology, Inc. (Midea Group Co., Ltd)
• Original Assignee: Munck Automation Technology, Inc. (Midea Group Co., Ltd)
• Inventors: Kausch, James R.
• Primary Examiner(s): Mitchell, David M.
• Assistant Examiner(s): Weaver, Ross
• Application Number:
  US07/135,984
• Time in Patent Office: 414 Days
• Field of Search: 180/274, 180/275, 180/277, 293/4, 340/61, 250/206, 250/211 R
• US Class Current: 180/274
• CPC Class Codes: B60K 28/00 Safety devices for propulsion-unit control, specially adapted for, or arranged in, vehicles, e.g. preventing fuel supply or ignition in the event of potentially dangerous conditions for electrically-propelled vehicles B60L3/00; road vehicle drive control systems for purposes not related to the control of a particular sub-unit B60W30/00; drive control systems specially adapted for autonomous road vehicles B60W60/00
• CPC Class Codes: B60K 28/14 responsive to accident or emergency, e.g. deceleration, tilt of vehicle

Abstract

A flexible bumper 11, 14 is provided on an automatic guided vehicle 10 carrying an emitter/receiver photocell 21 thereon in electrical connection with motor circuit 28 and brake circuit 29. When photocell 21 is actuated by a suitable relay, the photocell beam signal 27 (FIG. 1) is transmitted through fiber optic cables 22, 23, emitter 25 and receiver 26 to permit propulsion motor operation through motor circuit 28 and vehicle brake release through brake circuit 29. If vehicle 10 strikes an obstruction safety bumper 11 is deflected, causing the aligned emitter-receiver beam 27 to be interrupted. This interruption of the beam signal to photocell 21 triggers motor circuit 28 to stop the motor and causes brake circuit 29 to set the vehicle brakes. When the obstruction is removed, the bumper deflects back to its normal position and light beam 27 is again transmitted to photocell 21 to permit brake release and motor operation to resume.

Various emitter-receiver locations for both unidirectional and bi-directional vehicles as illustrated in the several drawing figures are disclosed. In all embodiments of the invention, at least one of the emitter and receiver is carried by the flexible safety bumper.

Claims

1. In combination with an automatic guided vehicle,

deflectable bumper means mounted on the vehicle and adapted to signal contact with an obstruction;

a light source mounted on the vehicle and forming part of an electric circuit;

fiber optic emitter means in operative connection with said light source for transmitting a light signal therefrom;

fiber optic receiver means in spaced optical alignment with said emitter means for receiving a light signal optic emitter means and said

both said fiber optic emitter means and said fiber optic receiver means being secured to said deflectable bumper means and moveable therewith;

said fiber optic emitter means and said fiber optic receiver means when in optical alignment serving to complete an electric circuit that permits said automatic guided vehicle to operate; and

,

whereby when said deflectable bumper means contacts an obstruction said bumper will deflect and move said at least one of said fiber optic emitter means and said fiber optic receiver means out of optical alignment to thereby open the electric circuit and cause said automatic guided vehicle to stop.

2. The combination of claim 1 wherein said automatic guided vehicle is a bi-directional vehicle and said deflectable bumper means includes a front deflectable bumper and a rear deflectable bumper secured to opposite ends of said automatic guided vehicle;

said fiber optic emitter means comprises a pair of emitter units mounted, one each, adjacent an end of said front deflectable bumper;

said fiber optic receiver means includes a pair of receiver units mounted, one each, adjacent an end of said rear deflectable bumper; and

,

each of said receiver units being in optical alignment with one of said emitter units.

3. In combination with an automatic guided vehicle having an electrical propulsion motor and electrically controlled brakes, the improvement therewith comprising:

a photoelectric cell carried by said vehicle,

a first fiber optic cable connected at one end to and extending from said photoelectric cell,

a light signal emitter secured to the other end of said first fiber optic cable and adapted to emit a light beam signal from said photoelectric cell,

a second fiber optic cable connected at one end to and extending from said photoelectric cell;

a light beam receiver connected to the other end of said second fiber optic cable and adapted to receive the photo light beam emitted by said emitter when said emitter and said receiver are in optical alignment,

a deflectable bumper mounted on said automatic guided vehicle,

said emitter and said receiver being disposed in spaced relationship and at least one of the said emitter and said receiver being mounted on said deflectable bumper so as to be in optical alignment with the other of said emitter and said receiver,

said photoelectric cell being in electrical circuity with the electrical propulsion motor and electrically controlled brakes whereby when said emitter and said receiver are in optical alignment the electric motor will operate and the vehicle brakes are in released position and when said deflectable bumper contacts an obstruction, said emitter and said receiver will be knocked out of alignment to thereby cause the vehicle brakes to be applied and the electric motor to be inactivated.

4. The combination of claim 3 wherein said automatic guided vehicle is a unidirectional vehicle and said light signal emitter comprises a pair of emitter units mounted, one each, adjacent an end of said deflectable bumper and said light beam receiver comprises a pair of receiver units mounted, one each, on opposite sides of said vehicle in spaced adjacency and, in optical alignment with one of said emitter units.

5. The combination of claim 3 wherein said automatic guided vehicle is a bi-directional vehicle having a front deflectable bumper and a rear deflectable bumper;

each said front and said rear deflectable bumper spanning an end of said vehicle and having ends thereof connected to the sides of said vehicle;

said light signal emitter comprising a pair of emitter units mounted on each of said front deflectable bumper and said rear deflectable bumper adjacent the ends thereof connected to said vehicle;

said light beam receiver including a pair of receiver units mounted, one each, on said vehicle in spaced adjacency to the ends of said front bumper and a pair of receiver units mounted, one each, on said vehicle in spaced adjacency to the ends of said rear bumper; and

wherein said emitter units mounted on said front bumper are disposed in optical alignment with said receiver units mounted on said vehicle in spaced adjacency to the ends of said rear bumper and said emitter units mounted on said rear bumper are disposed in optical alignment with said receiver units mounted on the vehicle in spaced adjacency to the ends of said front bumper and wherein when said vehicle contacts an obstruction while moving in either direction the deflection of the encountered bumper will cause at least one of said emitter-receiver units to move out of optical alignment and effect vehicle brake application and motor stoppage.

6. The combination of claim 3 including said automatic guided vehicle being a bi-directional vehicle having a front and a rear end and provided with a deflectable bumper mounted on each of said front and said rear ends, and wherein said emitter is mounted on one of said bumpers and said receiver is mounted on the other of said bumpers and in optical alignment with said emitter.

7. The combination of claim 3 wherein said automatic guided vehicle is a unidirectional vehicle and including a pair of emitters mounted on said deflectable bumper and a pair of receivers mounted on the aft end of said vehicle chassis, each of said pair of receivers being in optical alignment with one of said pair of emitters.

8. In combination with an automatic guided vehicle having an electrical propulsion motor and electrically controlled brakes, the improvement therewith comprising:

a photoelectric cell carried by said vehicle,

a first fiber optic cable connected at one end to and extending from said photoelectric cell,

a light signal emitter secured to the other end of said first fiber optic cable and adapted to emit a light beam signal from said photoelectric cell,

a second fiber optic cable connected at one end to and extending from said photoelectric cell;

a light beam receiver connected to the other end of said second fiber optic cable and adapted to receive the photo light beam emitted by said emitter when said emitter and said receiver are in optical alignment,

a deflectable bumper mounted on said automatic guided vehicle,

both said emitter and said receiver being mounted on said deflectable bumper and disposed in spaced optical alignment relationship thereon;

said photoelectric cell being in electrical circuity with the electrical propulsion motor and electrically controlled brakes whereby when said emitter and said receiver are in optical alignment the electric motor will operate and the vehicle brakes are in released position and when said deflectable bumper contacts an obstruction, said emitter and said receiver will be knocked out of alignment to thereby cause the vehicle brakes to be applied and the electric motor to be inactivated, and

wherein the sensitivity of the electric motor and vehicle brake operation is adjustable by changing the spacing between said emitter and said receiver.