GB2368706A

GB2368706A - Monitor for detecting locked position of a vehicle stabiliser outrigger jacking leg

Info

Publication number: GB2368706A
Application number: GB0113190A
Authority: GB
Inventors: Mayus Karia
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-05-31
Filing date: 2001-05-31
Publication date: 2002-05-08
Also published as: GB0113190D0; GB0013075D0

Abstract

A safety monitoring system for stabilising outrigger jacking legs (9) of a vehicle (fig 1) indicates to the driver if the leg is in a locked or unlocked condition. The vehicle may be a lorry or truck with a crane (fig 1). The system is responsive to the condition of the locking mechanism (fig 2-3) of each of the outrigger jacking legs. The locking mechanism may comprise a slidable bolt 10 passing through a beam 8,11,12 and beam housing 7 to put the leg in an operative or retracted position. In the operative position, a retaining pin 18 locks the bolt in position, and a sensor switch 19 detects the proper location of the retaining pin. The switch 19 may be positioned so an actuator 20 of the switch 19 engages with a part 14 of the bolt.

Description

VEHICLE STABILISER MONITORING SYSTEM This invention relates to a vehicle stabiliser monitoring system and particularly to a system for monitoring the stowed condition of a laterally projectable jacking leg on a vehicle such as a vehicle-mounted crane.

A popular type of vehicle has a small crane mounted on the vehicle chassis between the vehicle cab and a lorry platform. The crane can be used for loading/unloading the lorry platform. In order to stabilise the vehicle whilst operating the crane, one or more laterally projectable jacking leg assemblies is often provided which enable the vehicle chassis, and hence the crane, to be stabilised against lateral tilting during operation of the crane to unload or load heavy items to or from positions alongside the lorry.

The projectable jacking leg assembly generally comprises a horizontal box-section beam which is retractable into a box-section beam housing for stowing a vertically extendable jacking leg mounted on the free end of the beam, the beam housing extending transversely of the vehicle chassis and being connected thereto. Often the beam housing is integral with the crane base.

The beam can be slid by manual force whilst the jacking leg is clear of the ground.

A manual locking mechanism is generally provided to lock the beam in the retracted condition whilst the vehicle is travelling, but this requires the vehicle/crane operator to be vigilant in ensuring that the beam is fully retracted and the locking mechanism properly engaged before the vehicle is driven, otherwise the beam may slide to a dangerous extended condition during travelling of the vehicle. There is also the possibility

that the locking mechanism could be tampered with by children or vandals whilst the vehicle is parked or at rest.

I consider that there is a need for a system which is capable of indicating when the beam has not been safely retained in the retracted condition prior to movement of the vehicle.

According to one aspect of the invention a monitoring system for a laterally projectable jacking leg of a vehicle comprises a sensor which is operative to sense the locked condition of a locking mechanism that is capable of retaining the jacking leg in a stowed condition, and means responsive to the output of the sensor to indicate to the vehicle driver the condition of locking of the locking mechanism.

The sensor may be connected to an electrical circuit that is arranged to provide a warning in the vehicle cab in the event that the locking mechanism has not been fully operated.

The warning device may, for example, be a flashing light on the dashboard or an audible warning device.

The sensor is preferably a switch which is mechanically operated on bringing a component of the locking mechanism to a fully secured condition.

In one known type of locking mechanism a bolt is slidable through cooperating holes in the beam and the beam housing in order to hold the beam in the retracted condition, and a retaining pin is adapted to be inserted through co-operating holes in the bolt and bolt housing to retain the bolt in the operative condition.

For use with a locking mechanism that employs a locking pin, I prefer that the arrangement is such that the sensor is operated in response to the locking pin being positioned in a locked condition thereof.

The sensor may be a switch unit fast with the locking pin, a switch actuator being operative to cause switching of the switch unit by engagement of the switch actuator with a part of the bolt housing.

Alternatively the switch unit may be mounted on the bolt housing in a position such that the switch actuator is operated by the locking pin when the locking pin has reached a fully engaged position.

It will be appreciated that proximity sensors rather than mechanicallyoperated switch sensors could be used.

An advantage of arranging for the sensor to be operated by a locking pin is that it is relatively easy to modify an existing vehicle.

When a vehicle is provided with a plurality of laterally projectable jacking legs, the respective sensors may be wired into a common sensor circuit, conveniently by wiring the sensors in series. This can easily be carried out on an existing vehicle at minimum cost.

A further sensor may be provided to detect when the beam is in a fully retracted condition. Such a beam condition sensor may conveniently be in the form of a switch unit positioned adjacent to the outer end of the beam guide, and arranged to be actuated by a formation on the beam, such as the top of the jacking leg, as the beam reaches a fully retracted condition. This could help to avoid the vehicle being manoeuvred whilst the jacking leg is in a projected condition (such legs tend to be positioned in a blind spot of the vehicle wing mirrors).

A second aspect of the invention comprises a vehicle fitted with a monitoring system in accordance with the first aspect of the invention.

A third aspect of the invention comprises a kit of parts for modifying an existing vehicle by providing the vehicle with a monitoring system in accordance with the first aspect of the invention, the kit of parts comprising a sensor which is adapted to sense the locking condition of a pre-existing locking mechanism capable of retaining the jacking leg of a vehicle in a stowed condition.

A vehicle stabiliser monitoring system in accordance with the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: Figure 1 is a partial side elevation of a lorry with a chassis mounted crane assembly; Figure 2 is a cross-sectional partial view on the line 2-2 of Figure 1 showing the left hand stabiliser assembly in a fully retracted and locked condition; and Figure 3 is an enlarged cross-section on the line 3-3 of Figure 2 showing the locking assembly of the left hand stabiliser assembly with the locking bolt and the retaining pin in their fully engaged positions.

Figure 1 shows schematically a common form of lorry 1 comprising lorry chassis 2, cab 3, load platform 4 and a crane assembly 5 mounted on the chassis between the cab 1 and the load platform 4. Integral with the crane base 6 is a box-section beam housing 7 for a pair of manually slidable transverse beams 8, also of box-section, the beams 8 supporting

at their outer ends a respective jacking leg 9 comprising a jacking foot 10 which is vertically movable by hydraulic pressure supplied through flexible hoses, not shown, from a hydraulic source, not shown, mounted on the crane base 6. The beam 8 and leg 9 constitute a transverselyretractable stabiliser assembly, and is of well-known configuration.

In order to lock the beams 8 in a stowed, inwardly retracted condition, as shown in Figure 2, a locking bolt 10, Figure 3 is provided for each of the beams 8.

As shown in Figure 3, the fully engaged locking bolt 10 extends through aligned holes 11,12 in the respective beam 8 and beam housing 7, the stem 13 of the bolt being housed in a tubular boss 14 fast with the housing 7.

A bolt operating handle 15 is pinned to the outer end of bolt 10, and the hub 16 of handle 15 has a camming engagement with the inclined outer end 17 of boss 14, so that when the handle 15 is turned to an upright position, the camming action withdraws the bolt 10 from the hole 11 to enable the respective beam 8 to be manually withdrawn to an extended condition, whereupon the jacking leg 9 can be extended hydraulically.

In accordance with the invention, a bolt locking pin assembly 17 comprises a pin shank 18 and a manually-operable switch unit 19 which is fast with the upper end of the pin shank 18, the switch unit 19 comprising a downwardly-projecting switch actuator 20 which is adapted to be operated by engagement with the upper surface of the boss 14 when the pin shank 18 is fully engaged with aligned vertical bores 21,22 provided in the boss 14 and bolt shank 13 respectively.

Of course, bores 21 and 22 are only in alignment, due to the known effect of the camming face 17, when the bolt 10 is in the fully engaged condition.

Thus switch actuator 20 is only operated to switch the switch unit 19 when the retaining pin is fully engaged in the bores 21,22, and the bolt is thereby prevented from being released.

An electrical lead 22 from the switch unit 19 is connected in a series connection with the output from the corresponding switch unit 19 on the other stabiliser assembly, and in series with a suitable electrical alarm in the cab 3 of the vehicle, the alarm unit being arranged to be disabled only in the event of both switch units 19 being actuated. Since this requires only a relatively simple circuit, a conversion kit for existing vehicles can enable the invention to be applied with ease to existing vehicles. The existing locking assembly 17 need only be modified to the extent that a replacement pin assembly is provided. The pin can be of known shape, apart from the provision of the switch unit 19. For example, pins of well-know split-pin shape, having one straight limb and one part circular retaining limb, can be employed.

If desired an additional sensor device can be positioned at, say, 30 in Figure 2 to monitor the retracted condition of the associated beam 8.

It should be appreciated that although the invention has been described by reference to a vehicle mounted crane assembly, the invention is applicable to other vehicles which are provided with transversely retractable jacking legs.

Claims

CLAIMS 1. A monitoring system for a laterally projectable jacking leg of a vehicle comprising a sensor which is operative to sense the locked condition of a locking mechanism that is capable of retaining the jacking leg in a stowed condition, and means responsive to the output of the sensor to indicate to the vehicle driver the condition of locking of the locking mechanism.
2. A monitoring system as claimed in claim 1 in which the sensor is connected to an electrical circuit that is arranged to provide a warning in the vehicle cab in the event that the locking mechanism has not been fully operated.
3. A monitoring system as claimed in claim 1 or claim 2 in which the sensor is a switch which is mechanically operated on bringing a component of the locking mechanism to a fully secured condition.
4. A monitoring system as claimed in claim 3 in which the locking mechanism comprises a bolt slideable through co-operating holes in the beam and the beam housing in order to hold the beam in the retracted condition, and a retaining pin is adapted to be inserted through cooperating holes in the bolt and bolt housing to retain the bolt in the operative condition, the arrangement being such that the sensor is operated in response to the locking pin being positioned in a locked condition thereof.
5. A monitoring system as claimed in claim 4 in which the sensor is a switch unit fast with the locking pin, a switch actuator being operative to cause switching of the switch unit by engagement of the switch actuator with a part of the bolt housing.
6. A monitoring system as claimed in claim 4 in which the switch unit is mounted on the bolt housing in a position such that the switch actuator is operated by the locking pin when the locking pin has reached a fully engaged position.
7. A monitoring system as claimed in any one of the preceding claims in which a further sensor is provided to detect when the beam is in a fully retracted condition.
8. A monitoring system substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.
9. A monitoring system substantially as described herein with reference to Figure 3 of the accompanying drawings.
10. A vehicle fitted with a monitoring system in accordance with any one of the preceding claims.
11. A kit of parts for modifying an existing vehicle by providing the vehicle with a monitoring system in accordance with any one of claims 1 to 9, the kit of parts comprising a sensor which is adapted to sense the locking condition of a pre-existing locking mechanism capable of retaining the jacking leg of a vehicle in a stowed condition.