WO1993001952A1

WO1993001952A1 - Locking device for restraining loading bodies

Info

Publication number: WO1993001952A1
Application number: PCT/SE1992/000524
Authority: WO
Inventors: Anders ÖSTERLUND
Original assignee: Oljibe Ab
Priority date: 1991-07-19
Filing date: 1992-07-17
Publication date: 1993-02-04
Also published as: AU2333692A; SE468550B; SE9102210D0; SE9102210A

Abstract

A locking device for restraining loading bodies such as swap body platforms, lorry platforms and trailer platforms at loading bridges (6) comprising a mechanically operated lock shackle (12), activated by means of a sensor (14) and an operating means. The lock shackle is mounted on the loading bridge and the locking device is activated automatically to a locking position whereby the lock shackle grips round a mounted cross-member (9) under the rear edge of the platform (2).

Description

Locking device for restraining loading bodies

Brief description of the invention.

The present invention relates to a locking device for restraining loading bodies, such as swap body platforms, truck platforms and trailer platforms when these are stationary against a dock, said locking device having a mechanically operated lock shackle mounted under the loading bridge/drive on ramp and which together therewith forms a gripping claw which prevents the body from moving if the platform is effected by dynamic forces, such as, for example, a forklift truck braking on the platform.

Background of the invention.

It is possible, when working with only platforms of swap bodies, to mount hooks on the front edge/nose of the dock with which to hang/anchor the swap body. There are alternatives where one secures swap bodies with chains and tightening devices which are mounted to the dock and connected to a specially fitted fastening device on the swap body. The above mentioned hooks are however a hindrance to vehicles which have permanently mounted platforms preventing them from docking up in a loading dock which has this equipment. One is forced to separate the loading areas depending upon if the vehicle has swap body or permanent platform. Furthermore, this system is sensitive because if the ground level should change due to ground movements or snow which effects the distance between the ground and the height of the hook, the hook will not properly grip the girder at the rear end of the swap body. The alternative method with chains is heavy to work and is usually not used. A truck or trailer positioned for loading or unloading should be prevented from moving, besides by means of the braking system of the vehicle, by for example rubber chocks placed against the wheels. However, this is not always done, which results in accidents. Furthermore, the platform on a vehicle having air suspension can move longitudinally when loading /unloading is in progress so that the loading bridge/drive on ramp no longer lies upon the platform, which increases the risk of accidents.

The loading bridges/drive on ramps mounted on the loading dock (not included in the invention) are used to even out any optional height difference between the dock and the body and to stretch across the distance between the dock and the body. This means that a drive on ramp is a necessity to enable the handling of goods to be carried out on the body.

The loading bridge consists of a bridge plane, optionally provided with a drop-down or telescopic flap.

Detailed disclosure of the invention.

The object of the invention was to eliminate the above mentioned problems by means of a locking device as defined in the claims. According to the invention there is mounted under this loading bridge/drive on ramp a locking device comprising a lock shackle, which mechanically, for example, hydraulically, pneumatically or electrically swings out and grips round a mounted member under the body's rear end.

The activation of the lock shackle into a locking position is preferably carried out automatically via a sensoring device mounted on the loading bridge.

The lock shackle may be U-shaped, preferably made of steel, aluminum or plastic and provided with a block of a material with high friction such as, for example, rubber. This block is mounted on the shackle in such a way that the horizontal movements of the platform decrease when loading and unloading on the platform. Thereby the platform feels very secure to work on.

Furthermore, the wear and tear of the legs of a positioned swap body decreases.

The mounted cross-member on the rear end of the platform is, for example, made of steel and shall be placed in alignment with the platform's rear edge and at a suitable height which may, for example, consist of a square cross section member mounted under the platform. By means of the gripping claw which is formed by the lock shackle and the flap of the loading bridge the mounted cross-member on the platform cannot move forward.

The shape of the lock shackle is adjusted to the shape of the loading bridge and to the mounted cross member on the platform and is provided with a catch heel which limits the possibility of the platform moving longitudinally. The lock shackle is, for example, made of steel or other material dimensioned to hold the horizontal load in question.

One particular advantage with the construction according to the invention is that the placing of the locking device under the loading bridge always gives a complete hold, independently of the height of the platform (leg height, ground movements, snow, etc.) since the relationship between the flap of the loading bridge and the cross member mounted on the platform are always of the same height.

Neither do variations during loading cause any problems in the event of, for example, the suspension sagging down or the legs sinking down into the floor/ground since the loading bridge follows after/lies on the body platform. This means that the lock construction only is encumbered with horizontal forces.

A particular advantage with the construction according to the invention is that the use thereof is not restricted to vehicles provided with a so-called rear-end lift. The operating of the lock shackle takes place after a sensor, placed under the loading bridge, registers if the loading bridge flap is in resting position. When the loading bridge flap leaves its resting position this is indicated by the sensor and if the locking device is not manually interlocked the operating current is switched on to an hydraulic unit after a delay via a time relay and a hydraulic piston pushes the lock shackle into locking position.

By means of the automatic activation of the locking device according to the invention, the human factor is eliminated as far as possible.

The sensor may be an optical sensor (photocell) of the type common transmitter/receiver of modulated infra red (IR) light according to known technique.

The initiating of the operating current may in another embodiment take place by, for example, activating a mounted impulse device.

To prevent damage occurring on the loading bridge, if the tractor/truck driver does not operate the lock shackle to a resting position before the vehicle drives away, a part of the lock shackle which comprises the catch heel and the block made of rubber for example, may be fastened to the lock shackle in such a way that they are released from the lock shackle on horizontal loads less than the loading bridge's dimensions for maximum horizontal loads and in excess of the horizontal load which occurs when the platform inadvertently is set in motion. One example of such a fastening device are pins which on abnormal loading are broken.

If the construction according to the invention only shall be used for restraining of swap bodies a photocell of the type common transmitter/receiver is mounted parallel to the dock to indicate that a swap body is in place. The device according to the invention is connected to electrical operating equipment suitably mounted in a control panel which contains equipment for driving the sensor/ photocell, equipment for monitoring the operation of the mechanical parts, the hydraulical parts for example, equipment for operating the warning lights, equipment for locking of the loading dock bridge as well as a switch provided with an indicating light.

Due to the fact that the locking device is situated under the loading bridge and is not easily visible to the user, the front of the control panel is provided with indication lights which indicate on one hand when the lock shackle is in resting posi¬ tion, and on the other hand when the lock shackle has reached working position. The front of the control panel is also provided with an impulse device, described as "RETURN LOCK", with which the lock shackle is guided to a resting position and an impulse device for clamping the locking device. Said clamping device is released when the beam from the sensor once again does not reflect.

Furthermore, there is provided for the vehicle driver an easily visible warning light which indicates when the locking device has left its resting position and an easily visible warning light for the loading personnel which indicates that the locking device is in working position.

During the time the lock shackle is not in resting position the loading bridge is clamped (is not operable) . The clamping is carried out according to known technique.

Brief description of the drawings.

Figure 1 illustrates a side view of a loading dock (7) with a stationary platform (2) having a covering (3) standing on support legs (4) the loading bridge (6) being in resting position, the locking device (1) being in resting position, a warning light (15), a warning light (23), and illustrating how the truck traffic/goods handling (8) is carried out on the platform (2) when the loading bridge is in working position. Figure 2 illustrates a plan of a loading dock (7) with a stationary platform (2) having a cross-member (9) and illustra¬ ting the position of locking device (1) .

Figure 3 illustrates a detailed drawing of the locking device (1) in resting position with lock shackle (12) and block (24), the loading bridge (6) being in resting position with the bridge plane (11) and flap (10) the hydraulic cyclinder (13) the sensor/photocell (14) and the cross-member (9) of the platform (2).

Figure 4 illustrates a detailed drawing of the locking device in resting position, the loading bridge (6) with flap (10) in working position.

Figure 5 illustrates a detailed drawing of the locking device (1) in working position, the loading bridge (6) with flap (10) in working position and the cross member (9) of the platform (2) . Figure 6 illustrates a front view of the lock shackle (12) and sensor/photocell (14) and the bridge plane (11) . Figure 7 illustrates a plan of the loading dock (7) with photocell (16) reflector (29) and truck (26) .

Figure 8 illustrates a side view of the loading dock (7) with a truck (26) which breaks the beam of the photocell (16) . Figure

9 illustrates a side view of the loading dock (7) and a platform (2) which does not break the beam of the photocell (16) . Figure

10 illustrates one embodiment of a control panel having in¬ dicating lights (17, 19 and 20) and switch (18), impulse device RETURN LOCK (21) and impulse device STOP LOCKING (27) .

Figure 11 illustrates a detailed drawing of the lock shackle (12) in working position with the clamping heel (25) and rubber block (24) fastened into the lock shackle (12) with security pins (28) .

Description of the preferred embodiments.

According to one embodiment of the invention the tractor backs against the loading bridge (6) . When the vehicle is stationary at the loading bridge, the swap body is released, the tractor drives away and optional doors on a covering (3) of the swap body (2) are opened, the loading bridge (6) is raised by means of the plane of the bridge (11) being driven up to a level above the floor level of the swap body, whereby the flap (10) swings from vertical to horizontal position in accordance with known technique. Thereafter the bridge sinks of its own weight down to the swap body floor. A sensor, a photocell (14) for example, of the type common transmitter/receiver, placed under the loading bridge (6) and directed to the bridge flap, registers if the flap has left its resting position. If the sensor indicates that the bridge flap has left its resting position, a time relay starts, to enable the flap (10)/bridge plane (11) which is then above the body (2) to have time to sink down onto the floor of the body before the lock shackle (12) starts to move. When the time relay has reached time point zero and the locking device is not manually clamped with the impulse device "STOP LOCKING" the hydraulic aggregate starts and the hydraulic piston (13) pushes the lock shackle (12) round the cross member (9) under the platform into a locked position.

If a loading bridge lacks a flap, according to a further preferred embodiment the sensor is placed under the loading bridge facing a reflector or reflecting sheet metal attached to the loading bridge.

For the user an easily visible electrically connected control panel (Fig. 10) indicates on one hand if the lock shackle is in resting position, UNLOCKED (20) and on the other hand if the lock shackle is in working position LOCKED (19) by means of indicator lamps (20 and 19 resp.) indicating the respective alternative. During the time the lock shackle moves between resting and working position the lamps flash UNLOCKED (20) .

A warning light (15) easily visible to the driver of the vehicle indicates that the lock shackle has left its resting position and a warning light (23) easily visible to the loading personnel indicates that the locking device is in working position. When the lock shackle (12) leaves its resting position the loading bridge (6) is clamped and cannot be moved. Only when the lock shackle (12) is once again in resting position is the loading bridge (6) operable. When the loading bridge (6) is to be driven into resting position, according to known technique, the lock shackle (12) must first be driven to resting position by pressing the impulse device RETURN LOCK (21) on the control panel. When the lock shackle has reached resting position the clamp is disconnected from the loading bridge (6) whereon this may be driven to resting position. If the loading bridge (6) does not return within the time limit to which the time relay is adjusted the lock shackle (12) will once again take up working position.

If the device according to the invention only shall be used for restraining swap bodies it must be prevented from being activated by other types of stationary platforms and a photocell (16) of the type common transmitter/receiver may be mounted parallel to the dock (7) and suitably about a distance of 0.5 meter away from this and in series with the sensor (14) . If the beam of the photocell does not reflect against the reflector because some other type of body is used instead of a swap body or another vehicle is parked at the loading bridge, the lock shackle is prevented from leaving its resting position.

Claims

1. A locking device for restraining loading bodies at loading docks having a loading bridge (6) optionally provided with a flap, said locking device being provided with a mechanically monitored lock shackle (12) , activated via a sensor (14) and an operating means, c h a r a c t e r i z e d in that the lock shackle is mounted on the loading bridge and that the locking device, via the sensor, is activated automatically into a locking position whereupon the lock shackle grips round a cross-member (9) mounted under the rear edge of the platform (2) .

2. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the lock shackle is mounted under the| loading bridge.

3. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that when the loading bridge is provided with a telescopic flap the lock shackle is mounted under the flap.

4. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the lock shackle (12) is hydraulically operated.

5. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the shape of the lock shackle (12) is compatible with the cross-member on the loading body and is made of steel.

6. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the activation of the locking device is delayed by means of a connected time relay device which starts when the sensor (14) indicates that the loading bridge has left its resting position and is set at a time interval sufficient for the loading bridge (6) to take up working position on the body (2) before the locking device is activated.

7. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that if the loading bridge lacks flaps the activation of the locking device is delayed by means of a connected time relay device which starts when the sensor (14) indicates that the loading bridge has left its resting position and is set at a time interval sufficient for the loading bridge (6) to take up working position on the platform (2) before the locking device is activated.

8. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that it is connected to one for the driver of the vehicle clearly visible warning light (15) which indicates that the lock shackle has left its resting position and one for the loading personnel clearly visible warning light (23) which indicates that the locking device is in working position.

9. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the sensor consists of a photocell.

10. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that it is provided with a photocell (16) mounted parallel to the dock (7) and in series with the sensor (14) .

11. A locking device according to claim 1, c h a r a c t e r¬ i z e d in that the lock shackle (12) on the surface lying close to the cross member (9) is provided with a block (24) consisting of a material having good friction.

12. A locking device according to claim 1, c h. a r a c t e r- i z e d in that the catch heel (25) of the lock shackle (12) and the block (24) are secured to the lock shackle in such a way that the catch heel and block are freed upon abnormal horizontal loading.