EP0052088A1

EP0052088A1 - Collision guard

Info

Publication number: EP0052088A1
Application number: EP81850197A
Authority: EP
Inventors: Ewert Lindell; Bertil Wolgast; Göte Granath
Original assignee: Bygg- och Transportekonomi (BT) AB
Current assignee: Bygg- och Transportekonomi (BT) AB
Priority date: 1980-11-06
Filing date: 1981-10-23
Publication date: 1982-05-19
Also published as: SE436184B; SE8007824L; FI813345L; DK490581A; NO813545L

Abstract

A vehicle (1) is equipped with two rearward-protruding arms (3,4) preferably spring-loaded which on reversing into an obstacle are telescopically pressed in and so actuate elements which cause the vehicle to stop or reduce its speed. The arms (3, 4) are provided with at least two devices (5, 8) for emitting and receiving radiation which passes between the arms (3, 4) the said devices (5,8) controlling the drive unit of the vehicle in such a manner that an interruption in the beam of the second device (7, 8) causes the vehicle to stop unless two sensing elements (9, 10) mounted on each arm (3, 4) between the first device (5, 6) and the second device (7, 8) have both indicated that a pallet-like object has been introduced between the arms (3, 4), causing the vehicle to stop if a person, for example, is standing in its path but allowing it to continue if a pallet, for example, is there.

Description

The present invention relates to an improved collision guard primarily for driverless industrial trucks designed to carry pallets, etc. When the vehicle reverses to fetch a pallet or other load it must not run into a human being or other obstacle. It is therefore necessary to "teach" the vehicle to distinguish between obstacles like people, when it must stop, and other objects like pallets which it is to fetch.
According to the invention this problem is solved by providing the vehicle with two rearward-protruding arms located on either side of the load and accordingly straddling it. The arms can themselves cause injury if they strike anyone while the truck is reversing and they are therefore spring-loaded and fitted with switches or corresponding elements which cause the vehicle to stop or at least reduce its speed when the arms come into contact with anything.
The arms are fitted with at least two devices which transmit and receive suitable continuous or intermittent acoustic or electromagnetic waves such as infrared light, radar or ultrasonics passing between the arms.
The devices control the drive unit of the vehicle in such a manner that an interruption in the beam of the first device causes the vehicle to reduce speed and an interruption in the beam of the second device causes the vehicle to stop unless two sensing elements on each arm between the first and the second device have both indicated that a pallet-like object has been introduced between the arms. For example, if a person is standing in the way between the arms only one or none of these sensing elements will be actuated. The vehicle 6ill accordingly stop.
A version of the invention is described below with reference to the appended drawing, where

Fig. 1 shows a vehicle viewed from above, and where
Fig. 2 shows a detail enlargement of the broken-line frame in Fig. 1.

The chassis of the vehicle is designated with the numeral 1 and the load-carrying elements, which consist of forks, for example, with the numeral 2. The vehicle 1 is equipped with rearward-protruding arms 3 which extend beyond the load-carrying elements 2. Each arm consists of an inner portion 3 situated nearest the vehicle 1 and an outer portion 4. The outer portion 4 slides telescopically into the inner portion 3 against spring pressure. The purpose of this arrangement will be evident from the following description of the method of operation of the apparatus.
One of the aforementioned arms 3 is fitted on the side facing the other arm with at least two radiation-emitting devices (transmitters) 5, 7. Opposite the aforementioned radiation-emitting devices 5,7 are radiation- receiving devices 6,8. The latter devices may also consist of reflectors which reflect the beam back to the respective transmitter 5, 7, which is then combined with a receiver.
Between transmitters 5,7 and receivers 6, 8 on each arm are devices 9, 10 which sense objects in their immediate vicinity. In the most simple case they may consist of switches fitted with actuating "feelers" but may also consist of more complicated apparatus such as radar equipment.
The vehicle described above works in the following manner. When the vehicle 1 reverses towards a pallet (not shown) the pallet is introduced between the arms 3, 4. The beam between the outermost radiation-emitting and receiving devices 5, 6 is then interrupted and the speed of the vehicle 1 is reduced. As the vehicle continues its movement in reverse the pallet is brought into contact with both the sensing elements which then indicate that the intended object is situated between the arms 3, 4 with the result that the vehicle is not qaused to stop when the beam between the inner radiation-emitting and receiving devices 7,8 is interrupted. In the event that another object or a person is caught between the arms 3, 4 during the reversing movement of the vehicle the outermost ray is interrupted in the same manner as described above and the speed of the vehicle is reduced. In this case, however, the two sensing devices 9, 10 are not actuated simultaneously since the distance between the arms is too great with the result that when the inner beam is interrupted the vehicle 1 is caused to stop.
Should either of the arms 3, 4 strike an object during the reversing movement the outer arm 4 is pressed against spring pressure into arm 3 with the result that switches or similar devices cause the vehicle 1 to stop.
By means of the invention a collision guard has accordingly been achieved which effectively prevents injuries to persons and damage to objects.

Claims

1. Collision guard primarily for pallet-handling vehicles (1) with load-carrying elements (2), characterized in that the vehicle (1) is equipped with two rearward-protruding arms (3, 4) on either side of the vehicle, the said arms (3, 4) being fitted with detecting elements (5, 6, 7, 8, 9, 10) for sensing objects situated between the arms (3, 4) and regulating the drive unit of the vehicle (1) so that its motion is retarded and interrupted if the presence of a non- intended object beside or between the arms (3, 4) is detected.

2. A collision guard as in Claim 1, characterized in that at least two of the detecting elements consist of devices (5-8) emitting and receiving radiation, in which connection the radiation-emitting devices (5, 7) are mounted on one of the aforementioned arms (3, 4) while the radiation-receiving devices (6, 8) are mounted on the other arm (3, 4) so that a beam from one of the radiation-emitting devices (5, 7) passes between the arms (3, 4) and is received by one of the radiation-receiving devices (6, 8), the said devices controlling the movement of the vehicle (1) in wuch a manner that an interruption in the beam of the device (5, 6) situated at the outer end of the nearest arm (3, 4) causes a reduction in the speed of the vehicle and an interruption in the beam of the other device (7, 8) causes the vehicle to stop.

3. A collision guard as in Claim 2, characterized in that the detecting elements embrace a sensing element (9, 10) mounted on each arm (3, 4) and so arranged that both the elements (9, 10) are actuated if a pallet-like object is introduced between the arms (3, 4) in which case the movement of the vehicle is not affected while if only one or none of the elements (9, 10) is actuated by an object between the arms (3, 4) the movement of the vehicle is stopped.

4. A collision guard as in Claim 3, characterized in that the sensing elements (9, 10) are arranged between the radiation-emitting (5, 7) and radiation-receiving (6, 8) devices on the arms (3, 4).

- 5. A collision guard as in any of the foregoing claims, characterized in that each of the arms consists of two parts (3, 4), namely an inner part (3) situated nearest the vehicle (1) and an outer part (4) of which the outer part (4) is arranged to slide telescopically inside the inner part (3) against spring pressure, when on reversing into an obstacle the outer part (4) is pressed into the inner part (3) and in so doing actuates elements which cause the vehicle (1) to stop or reduce its speed.

6. A collision guard as in any of the foregoing claims, characterized in that the radiation-emitting elements (5, 7) are arranged to emit continuous or intermittent acoustic or electromagnetic waves.