This invention relates to a method and apparatus for inhibiting movement.

Reference throughout this specification will be made to inhibiting movement between two bodies such as a coupled truck and trailer unit. However it should be appreciated that the present invention has applications outside this field as well.

In conventional means of coupling a truck and trailer together, there is provided a turntable mechanism. This mechanism allows relative rotation of the trailer with respect to the truck, and gives the combined truck and trailer unit greater manoeuvrability and easier cornering characteristics.

Unfortunately there exists a significant safety problem in existing turntable mechanisms. This involves the lack of means of preventing over-rotation of the trailer with respect to the truck. Such over-rotation may occur when the brakes of the truck are applied suddenly, which leads to a situation commonly called jack-knifing. When jack-knifing occurs it often leads to subsequent loss of control of the truck and trailer unit, and has in the past contributed to many serious road accidents. A turntable mechanism whereby jack-knifing is prevented would be a significant advance over conventional turntable mechanisms, and would greatly contribute to increased road safety.

In this specification the word turntable refers to any mechanism whereby a means is provided for coupling an outer body to a inner body, whereby rotation of the outer body with respect to the inner body is allowed.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the enβuing description which is given by way of example only.

According to one aspect of the present invention there is provided a means of inhibiting rotational movement of an outer body with respect to an inner body, wherein a reservoir is defined between the two bodies, said means of inhibiting rotational movement including at least one partition extending from the outer body to the inner body and at least one partition extending from the inner body to the outer body, said partitions acting to divide the reservoir into at least two portions, and wherein at least one partition has means to control the flow of fluid from one portion of the reservoir to another portion.

In a preferred embodiment of the present invention there may be provided an inner and outer body attached to a truck unit. The inner body may be fixed rigidly to the truck, while the outer body may include a means of allowing rotation with respect to the truck. The outer body may also include a means of coupling to a trailer.

A reservoir may be defined between the two bodies and form a closed volume in which a substantially incompressible fluid may be contained. A first and second partition may be provided whereby, the first partition is fixed rigidly to the inner body, and the second partition is fixed rigidly to the outer body. The two partitions, divide the reservoir into two portions. A controllable valve may be included in at least one of the partitions.

When the outer body is moved with respect to the inner body, the partition attached to the outer body mπvpifl with it. As the partition on the inner body remains stationary the effect of moving the outer body is that one portion of the reservoir defined by the partitions is erilnrgwd while the other portion reduces in size.

When the controllable valve is operated to allow flow of fluid between the portions of the reservoir, the inner and outwr bodies can freely rotate with respect t.n ftfl h other.

When the valve is operated to prevent flow of fluid between the portions, the reβifl anrΛ nf p. fluid tn compression in the plosed portions prevents further relative rotational motion ui ^' the outer body with respect t.n the inner body.

When URfi in truckb and trailer units, the. valve rn~y be operated before the trailer has over-rulaied with respect to the truck to lock the turntable by preventing fluid flow between the portions. This means of preventing further rotation will act to substantially reduce the possibility of jack- knifing.

Further embodiments of the present invention are envisaged whereby the inner and outer bodies are attached to vehicles other than trucks or trailers, or where the inner and outer bodies are attached to any other bodies, not necessarily being vehicles.

In some embodiments of the present invention there may be provided an extra partition or partitions to those described above, and perhaps more than one valve. There may also be provided composite inner or outer bodies or further variations not substantially affecting the functioning of the present invention.

Various means of controlling the flow of fluid are envisaged. Such a means may be a barrier designed to be slidable in and out of the reservoir, or may be a valve designed to limit the flow of fluid between maximum and minimum amounts, thus limiting the relative rotational speed of the outer body with respect to the inner body to a maximum and minimum value.

In a preferred embodiment of the present invention there is included a controllable valve including an aperture. The valve may have controllable orientation, so that in some orientations the aperture provides a means of allowing flow of fluid through the aperture, while in further orientations the flow of fluid is prevented. Other means of controlling flow of the fluid are also envisaged.

According to an alternate aspect of the present invention there is provided a method of preventing movement of a first vehicle body with respect to a second vehicle body, said vehicle bodies connected by a turntable, said method of preventing movement characterised by the step of locking movement of the turntable when the brakes of the vehicle are applied.

In a preferred embodiment of the present invention, a method of locking movement of the turntable when the brakes are applied includes operation of a remote flow control apparatus. This apparatus may be attached to the braking means of the first vehicle body. As the brakes are applied the remote flow control apparatus adjusts a controllable valve to prevent the movement of the turntable. This in turn prevents further movement of the second vehicle body with respect to the first vehicle body.

When applied to truck and trailer units, this method of locking movement of the turntable may prevent jack-knifing of the trailer, providing the brakes are applied before over-rotation of the trailer has already occured.

This is generally the case as appHcation of brakes is a frequent cause of jack-knifing.

In a further preferred embodiment of the present invention the remote flow control apparatus is an air cyHnder which is connected to the braking mechanism of either vehicle by a solenoid valve. This valve may be operated by the same electronic circuit which operates the brake Hghts. The air cylinder may be connected to the controllable valve described above. Application of the brakes may cause the solenoid valve to operate the air cyHnder and hence the controHable valve to lock the turntable.

In a further preferred embodiment of the present invention, as the brakes are applied, the remote flow control apparatus may close a controllable valve preventing further flow of an incompressible fluid between each portion of the reservoir. Rotation of the outer body with respect to the inner body may be prevented, locking the turntable and eliminating risk of jack- knifing. A return spring on the controllable valve may also be provided so that when the brakes are no longer applied, the valve is returned to a position allowing the flow of fluid and thus rotation of the turntable.

In further embodiments of the present invention there may be provided a means of locking the movement of the turntable under circumstances where the brakes are not necessarily applied. Such circumstances may involve monitoring of the degree of relative rotation of the inner and outer body with respect to each other and locking the turntable if relative rotation of the two bodies exceeds a predetermined angle, or may involve the monitoring of various characteristics of the combined bodies, such as their speed or acceleration, and locking the turntable if these characteristics exceed predefined values. Various other circumstances resulting in the locking of the turntable are envisaged.

o

In further embodiments of a turntable mechanism according to the present invention there may also be provided a means of securing the turntable to another surface, such as a wear plate of another vehicle. Such means of attachment may prevent the movement of the turntable with respect to the wear plate.

The turntable may be attached to a wear plate by a central pin that allows rotation of the turntable with respect to the wear plate. This pin may have a quick release mechanism.

In a preferred embodiment of the present invention there is provided a turntable substantially aB described in any embodiment above, and including a means of locking the turntable to the wear plate by means of a locking pin.

In further embodiments of the present invention there may be provided a locking pin in addition to the quick release pin. This locking pin may prevent rotational movement of the wear plate and there may or may not be included in a means of disconnecting the locking pin. There may be included a cam to provide a means for removing the said pin.

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1: is a cross-sectional side view of an apparatus for inhibiting motion in accordance with a preferred embodiment of the present invention, and

Figure 2: is a cross-sectional top view of the apparatus illustrated in Figure 1, and

Figure 3: is a cross-sectional side view of a controllable valve in accordance with a preferred embodiment of the present invention, and

Figure 4: is a top view of a remote flow control apparatus and means of attachment to the controllable valve illustrated in Figure 8. and

Figure 5: is a cross-sectional side view of a truck trailer attachment means in accordance with a preferred embodiment of the present invention

With respect to Figure 1 there is illustrated a turntable mounting means generally indicated by arrow 1.

The turntable mounting means 1 includes a retainer plate 2, an outer casing 3, an inner rotor 4, an outer rotor 5, a turntable 9, a top retaining plate 6, bolts 19 and an oil reservoir 15.

The oil reservoir lδ is enclosed between the inner rotor 4, outer rotor δ, and top retaining plate 6.

The retainer plate 2 and bolts 19 fix the inner rotor 4 to the truck (not shown). The trailer (not shown) is attached to the turntable 9 by the means described in Figure 5. Thus when the controllable valve (shown in Figure 3) allows, the turntable 9, top retaining plate 6 and outer rotor 5 all rotate with respect to the inner rotor 4 and parts fixed thereto.

With respect to Figure 2 there is illustrated a cross sectional top view of the turntable mounting means illustrated in Figure 1.

A first partition 23 extends from the inner rotor 4 to the outer rotor δ, and a second partition 24 extends from the outer rotor 5 to the inner rotor 4. Both

partitions along with the inner rotor 4 and outer rotor 5 form an enclosure lδ which, in preferred embodiments, is filled with a substantially incompressible fluid (not shown) such as hydraulic oil. The enclosure 15 is also divided into two portions by the partitions 23 and 24, namely a first portion 27 and a second portion 28.

The second partition 24 includes a fluid flow channel 26 and controllable valve 16. The fluid flow channel 26 and controllable valve 16 allow fluid to flow between the first portion 27 and second portion 28 of the enclosure 15 when the controllable valve 16 is open, and prevents such flow when the controllable valve 16 is closed. During those times in which the controllable valve 16 is open, the outer rotor δ is able to rotate with respect to the inner rotor 4. However when the controllable valve 16 is closed no fluid can flow between the first portion 27 and second portion 28 of the enclosure 15 and rotation of the outer rotor δ with respect to the inner rotor 4 is prevented by the incompressability of the fluid in the appropriate portion.

With respect to Figure 3 there is illustrated a cross-sectional side view of a controllable valve generally indicated by the arrow 16. This includes an fluid flow port 17, a flow control valve arm 18, a bolt 19 and a flow control valve return spring 21.

The flow control valve arm 18 provides an area of attachment for a cable (not shown) that controls the rotation of the controllable valve 16, and allows the orientation of the fluid flow port 17 to vary. This selectively allows for the flow and non-flow of fluid through the fluid flow part 17. Such a flow may be controlled, for instance, by the application of a vehicle's brakes.

The flow control valve return spring 21 exerts a torsional force on the co troUable valve 16, and in some embodiments enables the controllable valve 16 to be returned to its original orientation when the brakes are released.

With respect to Figure 4 there is shown a top view of a remote flow control apparatus 20 and means of attachment to the controllable valve 16. The remote flow control apparatus 20 and controllable valve 16 are attached by a cable 30. When the brakes of the truck are applied, a signal may be sent from the brake lights (for example) to the remote flow control apparatus 20 which via the cable SO provides a torsional force on the controllable valve 16, thus enabling its orientation to be changed from a position where fluid flow is allowed to that to where fluid flow is prevented. This subsequently locks the turntable (shown in Figures 1 and 2) in position.

With respect to Figure δ there is provided a cross-sectional side view of a truck-trailer attachment means in accordance with a preferred embodiment of the present invention generally indicated by arrow 31.

Included in this attachment means is a turntable 9, a wear plate 11, a quick release pin 10, a quick release mechanism 22, a turntable locking pin 12, and a cam 13. The wear plate 11 will usually be connected to a trailer (not shown), and the turntable locking pin is usually connected to the cam IS. After the turntable 9 and wear plate 11 have been placed on top of each other translational movement of these bodies is prevented by insertion of the quick release pin 10. A further pin, namely the turntable locking pin 12 is inserted into both the wear plate 11 and turntable 9 to prevent any further motion of the wear plate 11.

In addition a quick release mechanism 22 is provided in the quick release pin 10 to allow for easy removal of the quick release pin 10. Such a release mechanism 22 helps prevent jamming of the quick release pin 10.

The turntable locking pin 12 is removed by rotation of the cam 13. Rotational movement of the cam 13 leads to translation of the locking pin 12 which may remove it from the turntable 9 and wear plate 11.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the spirit or scope thereof.