GB2119987A

GB2119987A - Traffic control system

Info

Publication number: GB2119987A
Application number: GB08209759A
Authority: GB
Inventors: James Steel
Original assignee: Ogden Electronics Ltd
Current assignee: Ogden Electronics Ltd
Priority date: 1982-04-02
Filing date: 1982-04-02
Publication date: 1983-11-23

Abstract

A traffic control system (10) for controlling movement of vehicles (11) comprises radar transducers (16, 17) for detecting presence of a vehicle (11) and signalling devices (18, 19) providing indication when movement of a vehicle (11) should be arrested, the transducers (16, 17) and the signalling devices (18, 19) being included in a control circuit so that the signalling devices (18, 19) indicate when movement of a vehicle should be arrested to avoid collision with an oncoming vehicle. The output from the transducers can also be used to control the operation of door 14. <IMAGE>

Description

SPECIFICATION Traffic control system This invention relates to a traffic control system.

It is well known to use fork lift trucks for transporting loads in factories and warehouses and, usually a plurality of fork lift trucks are used to transport a series of loads from one iocation to another. In such a case, it often occurs that a truck transporting a load travels along a path along which another truck returning to collect a further load moves in an opposite direction to the load carrying truck.

If an oncoming truck is visible to an operator of another truck on a collision path therewith, then one or other or both of the operators of the or each truck can control the truck to avoid collision. However, it ofter occurs than an oncoming truck is not visible to an operator of a moving truck because, for example, a collision path of the truck curves around an object, with a result that collisiln of the truck may occur.

It is desirable, therefore, to provide a traffic control system whereby movement of the trucks is controlled so as to reduce the possibility of collision.

According to the present invention, there is provided, a traffic control system comprising a detector for detecting an object moving in a predetermined direction relative to the detector and for generating a signal in an electric circuit when the said object is detected, and indicating device responsive to said signal for generating a further signal and an electric circuit connecting the detector and the indicating device so that, when the detector detects the presence of said object moving in said predetermined direction, the indicating device is operated to provide said further signal directed to a second object moving in an opposite direction to said predetermined direction indicating that the second object is moving in a collision path with said first object.

Therefore, movement of the object can be controlled in accordance with a signal indicated by the indicating device and collision of objects thereby is reduced or eliminated.

The circuit may include means responsive to said signal for effecting movement of a movable component relative to a stationary component.

In this manner, not only is relative movement of objects controlled but movement of the movable component also is controlled in accordance with movement of the objects.

The stationary component may be provided with an aperture and the movable component may be adapted to move to and from a position occluding the aperture.

In one example, the movable component is a door and the aperture is an opening in a wall of a building and the arrangement is such that movement of the door to open and close the opening is controlled by the electric circuit connecting the detector and the indicating device.

The detector may be adapted to detect a vehicle moving in said predetermined direction.

In this manner, the detecor will not effect operation of the indicating device if a body, such as a person, moves in said predetermined direction. The person may therefore walk along a path and the indicating device will not be operated although the indicating device will be operated if a vehicle moves along the path.

The detector may be adapted to generate and receive electro-magnetic radiation.

Following is a description, by way of example only and with reference to the accompanying drawings, of one method of carrying the invention into effect.

In the drawings: Figure 1 is a diagrammatic elevation, shown partly in cross section, of one enibodi- ment of the invention, and Figure 2 is a plan view of the embodiment shown in Fig. 1.

Referring to the drawings, there is shown a control system 1 0 for controlling movement of fork lift trucks 11 through an opening 12 of a wall 1 3 of a building, such as a factory or warehouse. The wall has mounted thereon a mechanism 1 4 for moving a door 1 5 mounted for movement to and from a position occluding the opening 12.

The system comprises a pair of transducers 16, 1 7 located on opposite surfaces of the wall 1 3 adjacent the opening 12, each transducer being adapted to transmit and receive electro-magnetic radiation and being caiibrated such that, if a fork lift truck 11 moves within the range of the transmitted radiation in a direction towards the opening 12, an electric signal is generated by the transducer 16, 1 7. Each transducer is included in a circuit (not shown) which also includes means for controlling operation of lamps of light signalling devices 18, 1 9 each having a red filter 20 and a green filter 21, the devices 18, 1 9 being located in spaced relation from oppisite sides of the wall 1 3. The circuit also includes the door opening mechanism 1 4 and is arranged such that the lamps behind the green filters 21 of each of the light signalling devices 18, 1 9 are operated and the door opening mechanism 1 4 is inoperative so that the door 1 4 occludes the opening 1 2 when no fork lift trucks 11 are within the range of radiation transmitted from either or both of the transducers 16, 17.

When a truck 11 approaches the door 1 4 such that a signal is generated by one of a transducers 16, 1 7 the circuit is controlled to switch off the lamp behind the green filter 21 of the light signalling device 18, 1 9 spaced from the opposite side of the wall 1 3 from the side of the wall which is being approached by the truck 11 and switch on the lamp behind the red filter 20 of the light signalling device.

In this manner, a visual warning signal is provided for an operator of another truck 11 approaching the door 14 in a direction opposite to the direction of movement of the first truck. The circuit also controls operation of the door opening mechanism 1 4 such that the door is moved frorn a position occluding the opening 14. The truck or, in the case of two trucks approaching the opening 1 2 in opposite directions, the first truck may then be driven through the opening 1 2 of the wall 1 3.

The door opening mechanism 14 may be controlled by a timing mechanism whereby, after a predetermined interval, the door 1 5 may be returned by the mechanism 1 4 to a position occluding the opening 1 2. The timing mechanism would not, of course, become operative if a truck 11 is waiting adjacent a light signalling device 1 S, 1 9 because the transducer 16, 1 7 adjacent the surface of the wall 1 3 facing the truck would be generating signals, due to the presence of the waiting truck, which would have the effect of controlling the circuit to maintain operation of the door opening mechanism 14 to ensure that the door 1 5 remains in a withdrawn position so as not to occlude the opening 1 2.

It will be appreciated that the door 1 5 and the associated mechanism 14 may be omitted and that the opening 1 2 may not be provided with a door or may be provided with one or more flexible flaps which may close or partially occlude the opening 1 2.

Claims

1. A traffic control system comprising a detector for detecting an object moving in a predetermined direction relative to the detector and for generating a signal in an electric circuit when said object is detected, an indicating device responsive to said signal for generating a further signal and an electric circuit connecting the dectector and the indicating device so that, when the detector detects the presence of said object moving in said predetermined direction, the indicating device is operated to provide said further signal directed to a second object moving in an opposite direction to said predetermined direction indicating that the second object is moving in a collision path with said first object.

2. A system as claimed in Claim 1 wherein the circuit includes means responsive to said signal for effecting movement of a movable component relative to a stationary component.

3. A system as claimed in Claim 2 wherein the stationary component is provided with an aperture and the movable component is adapted to move to and from a position occluding the aperture.

4. A system as claimed in any one of the preceding claims wherein the detector is adapted to detect a vehicle moving in said predetermined direction.

5. A system as claimed in any one of the preceding claims wherein the detector is adapted to generate and receive electro-magnetic radiation.

6. A traffic control system substantially as hereinbefore described and as iltustrated in the accompanying drawings.