GB2168302A - A mobile stabiliser - Google Patents

Abstract

A site located mobile stabiliser has a mating bar (3) to which tipping vehicles with suitable coupling facilities can be connected to provide stability during discharge of the load. <IMAGE>

Description

SPECIFICATION A Mobile Stabiliser for Tipping Vehicles It is well known in the Road Transport industry that the removal of loads from long vehicles by means of tipping the body and discharging with the aid of gravity is a serious accident prone activity which often results in the vehicle overturning.

The common trade term used for this is a "Roll' (or Rollover).

Rolling is caused by one of, or a combination of the following: 1. An unven or unstable ground surface.

2. Uneven loading or discharging.

3. Unbalanced suspensions on opposing sides of the vehicle. The term "suspension" is meant to include the support from tyres as well as springs.

4. Sticking loads.

5. Side Winds.

To clarify the objections of this invention an explanation of the causes commonly leading to a Rollover in Bulk Tipping Vehicles follows: Many bulk transport materials tend to adhere to the body front by the action of braking and to the floor and sides by their own weight and road vibrations which drive out the air from between the load and the retaining surfaces. In consequence of the above, before the load will discharge by tipping, the adhesion caused by large areas of partial vacuum has to be overcome in addition to overcoming the static friction existing between the load, and the front, floor and walls.

In transit road vibrations increase the wall loading of bodies to such an extent that it is common practice in the trade to include anti-spread bars or chains in the body specification to prevent the sides from bulging outwards and thereby exceeding the permitted legal width. This increased pressure between the load and walls further increases the partial vacuum and static friction needing to be overcome in the operation of starting the discharge operation.

Drivers often force the initial load breakaway and thereby start the act of discharging by reversing their vehicles quickly and then jamming on their brakes. This is a very effective but frequently disastrous method.

The simple way of commencing the load discharge operation would be to increase the angle of tip utilised but unfortunately vehicle instability increases as the angle of tip increases.

The following text and illustrations referred to, aim to clarify the above statements and explain the sequence of events most likely to have occurred in producing a Rollover.

The drawings Nos: 1. & 2. show a bulk articulated tipping unit with a bodylength of 10.36 mts and an inside height of 2.44 mts max. Drawn to a scale 1=64.

In the weight distribution examples shown on all illustrations, 100 weight units are taken as representing the weight of body and payload and 10 units of measure as representing the vehicle track width. Distributed weight examples are shown in percentage terms.

Figure 1 shows the unit in side elevation with the body tipped to an angle of 45 degrees to the horizontal. The mark '3 shows the assumed position of the centre of gravity of the body tipping gear and payload in its inclined position.

Figure 2 is an end elevation view of the unit in figure 1 with the assumed centre of gravity in the tipped position shown. This position assumes that the load is equally distributed and still in position, the ground perfectly level and stable and the support from the suspension at opposing sides of the vehicle equally balanced.

It must be noted that in the tipped position, the majority of that portion of weight of the body and payload which was formally imposed over the tractor axle assembly and performing a valuable low level stabilising function, has now been transferred to a high point above the trailer suspension where it will add seriously to stability problems as soon as any balance irregularity occurs.

If in the example shown in Figure 2 where the vehicles is in correct balance we suspend a plumbline from the C of G down to the ground line it will divide the track dimension of 10 into two equal units of 5 and the weight distribution will be 50% at both side A & side B.

The drawings Figure Nos. 3 and 4 show a sequence of events which frequently take place when events leading to a Rollover occur.

In figure 3 the fully tipped unit is shown in an unbalanced state with a Rollover potential. The load discharge has failed to commence. Assuming sound and equally balanced suspension the initial inclination as shown would be either the result of an uneven or unstable ground surface or of uneven load distribution or a combination of the above stated conditions.

If in the hypothetical case shown in figure 3, the plumbline test now divides the track dimension into units of 6 and 4 the weights imposed on A and B will be 40% and 60% respectively. As 10% of W was removed from the suspension at side A, the frame and body was raised simultaneously with the lowering of the side B. under the increased 10% W imposed, the result being to throw the body top over in a form of inversed pendulum swing with the ground as the pivot point.

This inverse pendulum swing once set in motion contains enough kinetic energy due to the height and mass involved to take it passed its ultimate resting place as shown in figure 3 and then return in a few diminishing swings until the suspension at side B supports the increased weight imposed.

This inverse pendulum swing is the most dangerous component of the tipping operation because it acts like the driver's loosening technique Line 30 Page 2 of reversing and braking to shake the load loose but it does it more slowly and takes the load from the wrong side first for the reasons described below.

When a load remains in a body already tipped to an angle which would normally discharge same, it is retained there partially by static friction and partially by vacuum between areas of the load, front, floor and walls.

In figure 1 the shaded area C can often be largely retained by wall pressure even when all support provided by the rear door has been removed. The load at side A however now has side wall pressure reduced being the high side.

The wall pressure on side B however is increased as is the power required to overcome static friction and areas of partial vacuum. Any freeing of the load must now start first of all at side A and in fact proceeds in a manner and order as portrayed by the shaded portions C.D.E. and F.

in figures 3.4. and 5.

With each movement of load portions, the C of G of body and payload moves generally along an approx path as indicated by an arrow until a situation is reached where the C. of G. is at or over the pivot point on side B as in Figure 4 and 5 and the unit goes over sometimes helped with body swing or wind.

It is quite feasible and common in practice for the last portion of the load as portrayed in the shaded portion F in figure 5. to discharge from the body coinciding with the Rollover of the vehicle, so as to convey the impression erroneously, that the Rollover took place after the load had been totally discharged and that the cause of the accident was some failure of mechanical part or component which was in fact damaged as a consequence of the Rollover, and not the cause.

In common use are so called "TIPPING PLAT FORMS" on to which vehicles are driven and secured. Thereafter by means of the platform's own hydraulics the whole combination is tipped and the cargo safely discharged.

Such tipping platforms as referred to above are costly to purchase and install and commercially viable only for locations of a permanent nature.

Many road construction operations, large building projects and landfill operations because of the unsatisfactory and temporary nature of their material reception areas, us smaller or special types of vehicles to deliver their materials for reasons of safety.

The larger popular bulk tipping vehicles which are only viable where accurately laid concrete foundation platforms are provided, could be used with commercial benefits resulting if added safety in the tipping discharge of their cargo was provided.

This invention aims to eliminate partially, if not entirely, the risk of tipping vehicle Rollovers by using a piece of mobile equipment which is cheap to produce, has no realiseable value to thieves and is vandal-proof.

A description of its construction and use and the principles employed follows: Each vehicle involved is fitted with twin mechanical jaws attached at the rear in which the lower jaws ITEM NO. 1 on figure Nos. 6 and 8 are fixed and the upper jaws ITEM NO. 2 on figure 6 and 8 are operable so as to firmly grip a mating bar ITEM No. 3 on figure Nos. 6,7,8,9 and 10 on a sit located mobile stabiliser. The stabiliser can be either an individual component as illustrated in figures 6,7,8 and 9 or, where a concentrated reception area is involved a continuous girder ITEM 4 to which a series of mating bars ITEM 3 are attach Figure 10.

Where shown, item No. 5 is a spill tray for operating tidiness purposes. The operating procedure and benefits are described below: 1. The mating bar 3 is set to a height at which the vehicle mounted jaws ITEM 1, will pass beneath and collect the stabiliser when the vehicle is in the laden state.

2. The upper jaws ITEM 2 are locked on to the mating bar 3 in which condition the weight of the vehicle rear, body and payload all by-pass the suspension (and tyres) and are transferred directly on to the ground. The main problems of vehicle unbalancing are eliminated. LINES 9,74 - 78.

3. The fulcrum point of any potential rollover is moved away from the vehicle-centre line with vastly increased stability resulting Figure 11.

4. Because the lower jaws, ITEM 1 are arranged to collect the mating bar 3 in the laden condition, the jaws will be high enough after the load has been discharged, due to spring and tyre reflection, to carry and re-position the stabiliser bar if required.

The method of attaching the mating bar 3 to the stabiliser is by means of attachment plates, ITEM 6. Figure 12. These plates are shaped so as to aid the connecting operation but have been deleted in earlier illustrations for reasons of clarity.

Claims (3)

1. A separate device capable of being transported from site to site which, any number of tipping vehicles equipped with suitable coupling facilities can be connected to provide increased safety and stability during the act of load discharging.

The stabilising assembly not forming part of the load carrying vehicle can, without detriment to the payload, be robust in construction and wide-spread dimensionally to move the fulcrum point of any potential rollover away from the vehicle centre line. Drawings Figures - 7-8 and 9 Sheet 4 refers.

One suitable means of connecting the load carrying vehicle to the stabiliser assembly is a hydraulically operated jaw item 2 sheet 3.

2. A separate stabilising assembly according to claim 1, in which the receiving bar figure 3, sheet 3 is attached to the carrying vehicle and the hydraulic operating jaw item 2, sheet 3 is located on the separate stabiliser assembly. This reversed operation provides the load carrying vehicle with a desirable safety under-run bar at the rear.

3. In combination a mobile device to which typing vehicles can be connected as claimed in Claim 1 in which the coupling facilities are provided by a mechanically controlled connection.

3. A separate stabilising assembly according to claims 1 and 2 in which the method of connecting the carrying vehicle to the stabiliser assembly is by mechanical means involving bringing a receiving bar, as Figure 3 Sheet 3 attached to the load carrying vehicle to engage into two open mouthed housings on the stabiliser assembly and locking the two components together for the duration of the unloading.

4. A tipping vehicle stabilising assembly according to any proceeding claim which when coupled to the load carrying vehicle forms a solid supporting assembly between the strung components of the vehicle which are the chassis frame, the body and the payload and transfers this weight directly into the ground. This action by-passes and safeguards the springs and tyres against the overloading which occurs as the still loaded body is tipped causing weight to be transferred rearwards.

Amendments to the claims have been filed, and have the following effect: Claims 1 - 4 above have been deleted or textually amended.

New or textually amended claims have been filed as follows:

1. In combination a mobile device to which typing vehicles can be connected by means of coupling facilities which are operated from the drivers cabin in order to provided increased stability during load discharging.

2. In combination a mobile device to which vehicles can be connected as claimed in Claim 1 in which the coupling facilities are provided by a hydraulically operated connection.