GB2144706A

GB2144706A - Ramp bridging device

Info

Publication number: GB2144706A
Application number: GB08416120A
Authority: GB
Inventors: Kurt Alten
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-05
Filing date: 1984-06-25
Publication date: 1985-03-13
Also published as: CH663599A5; DE3324131C1; JPS6036233A; GB8416120D0; GB2144706B; JPH0626983B2

Abstract

A bridging device comprises a pivotable bridge plate (1) having a pivotal or retractable and extensible extension portion (4) on its free end, in which the bridging device is caused to return to its inoperative position when a vehicle having a platform (5) to be loaded or unloaded leaves the vicinity of the ramp. To effect this the bridging device is provided with an ultrasonic detection system (11, 12) for detecting the presence of a vehicle, which system is disposed in the region of the free end face of the bridge plate (1). The detection system is so connected to the bridge control means by a suitable switching arrangement that the system returns the bridging device to its inoperative position when the vehicle is no longer in the vicinity of the bridging device. This system is actuated by, or simultaneously with, the extension movement of the extension portion (4) and is switched off by a limit switch which is actuated when tie bridge plate (1) has attained its inoperative position. <IMAGE>

Description

SPECIFICATION Ramp bridging device The invention relates to a ramp bridging device and, more particularly, to a bridging device including an ultrasonic detection system for detecting the presence, or absence, of a vehicle or the like in the vicinity of the device.

A bridging device is known which comprises a bridge plate pivotally mounted at one of its ends about a horizontal axis. The other, free end of the bridge plate has an extension portion associated therewith, the extension portion being either pivotal or extensible and retractable with respect to the bridge plate. The extension portion is displaceable between an operative position in which it is located on, and supported by, a platform to be loaded or unloaded and an inoperative position in which it is not so located. The platform is provided on a vehicle or the like.

In such known bridging devices, it is desirable to move the bridge plate and its associated extension portion into their inoperative positions when a vehicle which has been loaded or unloaded leaves the vicinity of the ramp. This is because of the danger to personnel if the device remains in its operative position, particularly if the operator is inattentive.

The present invention seeks to improve a bridging device of the above-described type so that the bridging device is positively returned to its inoperative position when the vehicle leaves the vicinity of the ramp.

According to the present invention, there is provided a ramp bridging device comprising a bridge plate pivotally mounted at one of its ends about a horizontal axis on the ramp, the other end of the bridge plate having an extension portion associated therewith, the extension portion being either pivotable or extensible and retractable between an operative position in which the extension portion is located on a platform to be loaded or unloaded and the extension portion and bridge plate are supported thereby and an inoperative position in which the extension portion is not so located wherein an ultrasonic detection system for detecting vehicles or the like located in the vicinity of the bridging device, the platform being provided on the vehicle or the like, wherein the components of the ultrasonic detection system are disposed in the free end region of the bridge plate.

Such an arrangement not only ensures that the presence of a vehicle in the vicinity of the bridging device is detected but is also capable of acting upon the control means for the bridging device so that the device is returned to its inoperative position when the vehicle has departed. This may be effected, for example, by raising the bridge plate, retracting the extension portion and subsequently lowering the bridge plate into the ramp plane. Obviously, switching and control means are necessary to achieve this. However, such means are well known per se and do not constitute any part of the subject-matter of the present invention.

In a preferred embodiment the detection system comprises two transmitters and associated receivers, one transmitter and its associated receiver being disposed on one side of the longitudinal axis of the bridge plate, and the other transmitter and receiver being disposed on the other side of the longitudinal axis. These members are interconnected in such a manner as to ensure that there is no possibility of errors being made. Each vehicle has, of course, a predetermined width and the ultrasonic detection system in such that it does not react when a narrow object such as, for example, a private car or a human being is located in front of the bridging device.

It is also advantageous to link the control means for controlling the bridging device to the ultrasonic system so that the system is only switched on when the extension portion is extended or is only switched on when the extension portion has been swung out.

One embodiment of the present invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal view, partially in section of a ramp bridging device in accordance with the present invention in its operative position; and Figure 2 is a plan view of the bridging device shown in Figure 1.

In the drawings, there is shown a bridge plate 1, the rear end of which is pivotally mounted about an axis 2 on the ramp 3 formed on the upper edge of a ramp 3. At the free end of the bridge plate 1, a longitudinally extending retractable and extensible extension portion 4 is provided. By suitably pivoting the plate 1 about the axis 2 and by extending the extension portion 4, a parallelepiped recess in the ramp 4 is covered. In such position, the extension portion is located on a platform of a vehicle or the like to be loaded or unloaded and supports the plate 1. The extension portion 4 is displaceably mounted by means of slider members 6 and the retraction and extension movements thereof are effected by means of a working piston and cylinder arrangement 7, the connections of which are not shown.

On each lateral side of the bridge plate 1, longitudinally extending, downwardly directed plates 8 are provided. On the plates 8, a transverse bar or crosspiece 9 is mounted. A lifting piston and cylinder arrangement 10 engages with the crosspiece 9 thereby causing the raising of the bridge plate 1.

The bridge plate 1 is sealed at its front or free end by means of a downwardly extending end plate 1'. Two ultrasonic systems 11 and 12, each of which is provided, in a conventional manner, with a transmitter and a receiver, are provided behind the end plate 1', that is to say, nearer the pivot axis 2. For this purpose, the end plate 1' is provided with one or two apertures to permit the ultrasonic waves to pass therethrough. However, the at least one opening is also provided to protect the ultasonic systems. These systems are set so that they can detect the presence of the vehicle or the like provided with the platform 5, and also so that they respond immediately to the control means for the bridging device when the vehicle or the like has left the vicinity of the bridging device.

If such a response is produced by both systems, control means, which are known per se, initially cause the bridge plate 1 to be upwardly pivoted by means of the cylinder 10. The extension portion 4 is then fully retracted by the working cylinder 7 and the bridge plate 1 and the retracted extension portion 4 are lowered into the recess of the ramp, possibly to such an extent that the bridge plate 1 is located on the surface of the ramp 3. In this end position, the bridge plate 1 may be secured in position by conventional means such as stop members.

The ultrasonic systems may be such as to be actuated when the slide member 6 and/or the extension movement of the extension portion 4 into the position shown in Figure 1 occurs. The systems are advantageously switched off by means of a switch or the like which comes into effect when the bridge plate 1 is in its inoperative position. Accordingly, the switch may be a limit switch which is actuated by being struck by the bridge plate 1.

The ultrasonic systems may also be utilised in bridging devices which have a pivotable extension portion. In such a case the extension portion lies approximately in the plane of the bridging device in its operative position it extends substantially vertically downwardly, at right angles to the bridge plate 1, in its inoperative position. The ultrasonic detection systems are still located at the front end of the bridge plate in such a manner that, when the extension portion is in its inoperative position, the detecting system is both protected and covered by and behind the extension portion.

Claims

1. A ramp bridging device comprising a bridge plate pivotally mounted at one of its ends about a horizontal axis on the ramp, the other end of the bridge plate having an extension portion associated therewith, the extension portion being either pivotable or extensible and retractable between an operative position in which the extension portion is located on a platform to be loaded or unloaded and the extension portion and bridge plate are supported thereby and an inoperative position in which the extension portion is not so located wherein an ultrasonic detection system for detecting vehicles or the like located in the vicinity of the briging device, the platform being provided on the vehicle or the like, wherein the components of the ultrasonic detection system are disposed in the free end region of the bridge plate.

2. A bridging device as claimed in claim 1, wherein the detection system is actuated simultaneously with or by the extension movement of the extension portion.

3. A bridging device as claimed in claim 1 or 2, wherein the detection system is rendered inoperative by the bridge plate adopting its inoperative position.

4. A bridging device as claimed in claim 1, wherein the detection system comprises two transmitters and associated receivers, one transmitter and its associated receiver being disposed on one side of the longitudinal axis of the bridge plate, and the other transmitter and receiver being disposed on the other side of the longitudinal axis.

5. A bridging device as claimed in any preceding claim, wherein the bridge plate is provided with a downwardly extending front wall at its free end, the components of the detection system being disposed, in a protected manner, behind the end wall.

6. A bridging device as claimed in claim 3, wherein a limit switch actuated by the bridge plate renders the detection system inoperative.

7. A bridging device as claimed in any preceding claim, wherein the extension portion is pivotai with respect to the bridge plate and the components of the detection system are disposed, in a covered and protected manner, behind the extension portion which extends generally downwardly in its inoperative position.

8. A bridging device as claimed in claim 4, wherein the two transmitter and receiver pairs are interconnected in such a manner that the bridging device is actuated only when both two receivers detect a vehicle or the like or when both receivers do not detect a vehicle.

9. A bridging device as claimed in any preceding claim in which the detection device is linked to the control means for controlling the operation of the bridging device.

10. A bridging device as claimed in claim 1, constructed and arranged to operate substantially as herein before described with reference to and as illustrated in the accompanying drawings.