GB2538253A

GB2538253A - Foldable tow bar

Info

Publication number: GB2538253A
Application number: GB1508057.5A
Authority: GB
Inventors: Griffin Robert
Original assignee: TOMCAT SPECIAL NEEDS INNOVATION Ltd
Current assignee: TOMCAT SPECIAL NEEDS INNOVATION Ltd
Priority date: 2015-05-12
Filing date: 2015-05-12
Publication date: 2016-11-16
Also published as: GB201508057D0

Abstract

A foldable tow bar 10 for connecting a carriage to a cycling device comprising a first tow bar portion 12, a second tow bar portion 14 and a pivotal connection 16 between the first and second tow bar portions 12, 14, the first and second tow bar portions 12, 14 being movable relative to one another about the pivot 16 between a substantially in-line position and a folded position, the pivotal connection 16 including a spring-loaded latch adapted to automatically engage when the first and second tow bar portions 12, 14 are moved from the folded position to the substantially in-line position, and a spring-loaded friction mechanism to impede rotation of the tow bar portions 12, 14 relative to one another about the pivot 16 when the latch is disengaged.

Description

FOLDABLE TOW BAR

The present invention relates to a foldable tow bar.

BACKGROUND TO THE INVENTION

A person of limited mobility, such as a young child or a person who uses a wheelchair, currently has limited options for enjoying the pleasure of cycling, as most systems are expensive and bespoke. Carriages or trailers which attach to bicycles, for example, are used to overcome this limitation and provide means for them to travel with another person.

Bicycle trailers of this type are well known and may enable a dependent or supervised person to enjoy the outdoors with cyclists. Typically, a trailer includes a chassis, a seat, a pair of wheels at the sides of the chassis, and a tow bar or towing arm. The tow bar is generally mounted to the rear wheel mounting of a towing cycle.

The tow bar may typically be attached to the trailer about a folding connection, which is secured by a removable pin. However, the tow bar itself may still be too long to stow effectively for transit and storage. Known arrangements tend to be clumsy to assemble, prior to going for a cycle ride, and folding or collapsing a tow bar risks the trapping of fingers, because it can swing unexpectedly and rapidly when not locked in position.

It is an object of the present invention to reduce or substantially obviate the aforementioned problems.

STATEMENT OF INVENTION

According to the present invention, there is provided a foldable tow bar for connecting a carriage to a cycling device comprising a first tow bar portion, a second tow bar portion and a pivotal connection between the first and second tow bar portions, the first and second tow bar portions being movable relative to one another about the pivot between a substantially in-line position and a folded position, the pivotal connection including a spring-loaded latch adapted to automatically engage when the first and second tow bar portions are moved from the folded position to the substantially in-line position, and a spring-loaded friction mechanism to impede rotation of the tow bar portions relative to one another about the pivot when the latch is disengaged.

Advantageously, the tow bar of the invention can be folded to substantially reduce or even halve its overall length, making it much easier to store when not in use. The automatic nature of the latch ensures straightforward deployment, and the friction mechanism prevents sudden unexpected movement, thereby significantly reducing the risk of trapping fingers.

The friction mechanism may include first and second friction plates held against one another by an adjustable spring bias, where the first plate may be rigidly fastened to one of the tow bar portions, and the second plate may be rigidly fastened to the other of the tow bar portions. The adjustable spring bias may include a spring, at least one force transfer element, and a nut. The friction mechanism may be provided on one or both sides of the pivotal connection, or at one or more positions on the pivotal connection. In other words, there may be first and second friction plates on both sides of the pivot. Preferably, each spring is disposed between two force transfer elements.

The friction mechanism compresses the friction plates together, generating friction sufficient to stop free rotation of the tow bar portions about the pivot as the plates are rigidly fixed to these portions. However, users can overcome the friction easily, and fold/unfold the tow bar without undue strain. This friction acts against the plates sliding freely over or against one another, preventing free rotation of the tow bar portions without a sustained moment that overcomes the static and dynamic friction present. The degree of friction between the friction plates may be varied through tightening or loosening the nut(s) at the end(s) of the pivot. This compresses the spring to various extents, thus modulating the spring bias i.e. the force transmitted by the spring through the force transfer elements, affecting the ease of rotation of one friction plate relative to the other by the desired amount.

By positioning each spring between two force transfer elements, typically washers, the nut and one of the friction plates each bear against a large surface area (i.e. the force transfer element) on opposing ends of the spring, i.e. much larger than the end of the spring alone, improving the effectiveness of the friction mechanism. Providing the mechanism on both sides increases the maximum amount of friction that can be applied, and distributes it equally about the pivot.

The spring-loaded latch may be disposed to one side of the pivotal connection and may engage with a keeper disposed to another side of the pivotal connection. The latch may include a latch pin mounted through a bracket on the first tow bar portion, a body mounted about the latch pin, a hook adapted to engage the keeper, and a lever to tilt the latch about the latch pin, releasably engaging the hook with the keeper.

The spring-loaded latch automatically engages with the keeper when the latch is opened from a folded position to a substantially in-line position. This mitigates the need to check that the tow bar is securely deployed, and the hook engages the keeper to prevent the tow bar from folding of its own accord, i.e. the tow bar can only be folded again once the latch is manually disengaged.

The pivotal connection may include at least one hinge pin, and hinge pin supports on each of the first and second tow bar portions, the or each hinge pin locating through the hinge pin supports to hingedly connect the tow bar portions. Preferably, the or each first plate is substantially semi-circular in shape.

The approximately semi-circular nature of the first plate means that there are no sharp corners that might cause injury. It also has a turning circle that matches the radius of the semi-circular part, so it can rotate without inadvertently engaging other parts of the tow bar, in particular the latch pin.

A detent plunger may be provided on the second friction plate. The detent plunger may be fixedly aligned with one of the outer apertures through the second friction plate. Outer apertures through the first and second friction plates may co-align by rotation of the first friction plate about the pivot. This enables the detent plunger to engage a pair of co-aligned outer apertures and substantially lock the pivotal connection by preventing relative rotation of the plates and hence tow bar portions. Preferably, the detent plunger is spring-loaded to facilitate the automatic engagement of co-aligned apertures.

The detent plunger acts as a secondary locking mechanism, or secondary latch, to secure the tow bar in an in-line position. The detent plunger supplements the latch by engaging perpendicularly at the side of the tow bar, as opposed to the top, where the latch engages. As the detent plunger maintains a constant position relative to the second plate, it can lock the second plate at successive angles to the first plate based on the positions of the outer apertures in the first plate.

The spring substantially prevents the detent plunger from disconnecting from the apertures in use, due to vibrations during travel, for example. The detent plunger is also minimally susceptible to vertical dislocation from travelling over uneven ground as it is parallel to the ground, extending from the side of the tow bar. If the detent plunger is manually pulled out of one or both co-aligned apertures and released after the tow bar is partially folded or unfolded, it can spring into a locking position automatically when two adjacent outer apertures are next co-aligned as the folding action continues.

If the friction mechanism is provided on both sides of the pivotal connection, i.e. if there are first and second plates on both sides of the pivot, a pair of apertures in the first and second plates on one side of the pivotal connection may align at the same time as a pair of apertures align in the plates on the other side of the pivotal connection.

This allows one or both sides of the pivot to be locked in place by blocking co-aligned apertures with the detent plunger, preventing unexpected or unintentional folding of the tow bar in use.

The first and second friction plates may each have a primary aperture to mount to the hinge pin. The first and second friction plates may have one or more outer apertures spaced circumferentially around their edge. The outer apertures may be spaced at intervals of substantially 90°.

This allows the tow bar to be locked in substantially folded and open configurations, at 0° and 180° respectively, if the plates are secured to each other through co-aligned apertures. It further allows the tow bar to be locked at an angle of substantially 90°, allowing one portion of the tow bar to act as a stabilising leg, so that a two-wheeled trailer may rest in a stable upright configuration without being attached to a towing vehicle or any other device.

The second friction plate may extend towards the latch more than the first friction plate. Preferably, the latch pin extends through one of the outer apertures in the second friction plate. More preferably, the or each second plate is substantially triangular in shape to facilitate its extension towards the latch more than the or each first plate.

The first plate thus has a turning circle that passes within the latch-engaged apex of the second plate, if the first is substantially semi-circular, for example. This allows unrestricted rotation of the first plate relative to the second plate as the plates rotate about the pivot, i.e. as the tow bar portions rotate relative to one another, because the first plate is unobstructed by the latch pin.

The pivotal connection may include a first geared portion pivotally mounted to a spacer element about a first pivot, a second geared portion mounted to the other end of the spacer element about a second pivot, the first and second geared portions being meshed together.

The use of a geared hinge provides for a very compact tow bar, as the pivots, for example hinge pins, can remain within the profile of the tow bar during movement to the folded or open positions. Separate pivots are required for each geared portion to allow contra-rotation of the portions relative to one another with simple meshed gearing.

Each geared portion may include one or more gears or cogs, and each gear may be a fixed gear with teeth around substantially at least one quarter, i.e. 90°, of its circumference.

This allows each geared portion to turn through at least 90° towards the opposing geared portion, allowing for a combined 180° folding of the tow bar. Limiting the angular coverage of each gear with teeth prevents the hinge from over-pivoting, i.e. pivoting outside its normal range of 0° to 180°. For clarity, 0° is when the tow bar portions are substantially parallel to but not co-axial with one another, and 180° is when the tow bar portions are disposed about the pivot to be both substantially parallel to and co-axial with one another.

The latch may be mounted to the first geared portion and the keeper may be mounted to the second geared portion.

This substantially prevents the gears from rotating against each other if a moment is applied, when the latch is engaged with the keeper. Consequently, the geared portions cannot turn of their own accord against each other to align the tow bar portions non-linearly whilst the tow bar is in use, which would otherwise destabilise the towing vehicle and its trailer.

The tow bar may include a guard means, and the guard means may be securable about the tow bar to restrict physical access to the pivotal connection.

This reduces the likelihood that a person travelling in the trailer will catch their fingers in the hinge of the pivotal connection or any moving parts when the tow bar is in use (either in motion or when stationary). The guard means may not need to be removed or disengaged to allow the tow bar to be actuated between open and folded position.

An interlock may be provided to substantially prevent accidental actuation of the pivotal connection.

This mitigates the likelihood of a person in the trailer from toying with and inadvertently disengaging the locking mechanism(s) (the latch and/or the detent plunger), which could destabilise the trailer when it is being towed.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings, in which: Figure 1 shows a perspective view of a first embodiment of a foldable tow bar with a pivotal connection in an open (or 'in-line') configuration; Figure 2 shows an exploded perspective view of the foldable tow bar of Figure 1; Figure 3 shows another perspective view of the foldable tow bar of Figure 1 in a folded configuration; Figure 4 shows a perspective view of a geared hinge assembly for use as a pivotal connection in a second embodiment of a foldable tow bar, with the friction mechanism not shown for clarity; and Figure 5 shows an exploded perspective view of the geared hinge assembly of Figure 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring firstly to Figures 1 to 3, a first embodiment of a foldable tow bar is indicated generally at 10. The foldable tow bar 10 includes a first tow bar portion 12, a second tow bar portion 14, and a pivotal connection 16 connecting the two portions together.

The pivotal connection 16 includes first and second spaced hinge pin supports 18 on the first tow bar portion 12, and a third hinge pin support 20 on the second tow bar portion 14.

The first and second hinge pin supports 18 are disposed at the end of the first tow bar portion 12, and extend outwardly to one side thereof (to the lower side as viewed). The third hinge pin support 20 is disposed at the end of the second tow bar portion 14, and extends outwardly on the same side of the tow bar 10 as the first and second hinge pin supports 18. The third hinge pin support 20 is sized to fit between the first and second hinge pin supports 18 when the tow bar 10 is assembled. Each hinge pin support 18, 20 has an aperture running laterally through its centre for receiving a hinge pin 22. When assembled, the hinge pin 22 and its supports 18, 20 effectively form a butt hinge, i.e. the pivotal connection 16. Each end of the hinge pin 22 is threaded to receive retaining nuts 24, 24a.

A latch is provided to automatically retain the tow bar portions 12, 14 in the in-line or in-use position. A bracket comprising two spaced supports 26 is disposed on the upper surface (as viewed) of the first tow bar portion 12. The supports 26 lie on the other side of the tow bar 10 to the hinge pin supports 18 for the main pivot 16. Central apertures are provided through the supports 26, which mount a latch pin 28. The latch is securely mounted to the latch pin 28. The latch pin 28 extends laterally beyond the edges of its bracket.

A keeper 30 is disposed on second tow bar portion 14, which lies adjacent the latch when the tow bar 10 is unfolded, or in-line.

The latch has a body 32 with a lateral through-bore for mounting to the latch pin 28. The latch body 32 also includes a hook 34 to latch onto the keeper 30 when the tow bar 10 is in an open or in-line position for towing. A lever portion 36 is positioned on the other side of the latch pin 28 to the hook 34, which can be pressed to tilt the latch about the latch pin 28 to release the hook 34 from the keeper 30. The latch is spring-loaded about the latch pin 28, so that the transition from a folded configuration to an open configuration allows the latch to engage automatically. This occurs as the tow bar 10 approaches an in-line configuration, because the keeper 30 bears against the spring-loaded latch, raising it until the hook 34 slides past the keeper 30. The latch then automatically springs back into position and engages the keeper 30.

For safety, the foldable tow bar 10 includes a friction mechanism to impede free rotation of the first and second tow bar portions 12, 14 about the pivot 16. The friction mechanism is provided on both sides of the pivot 16 in this embodiment, but it may be provided only on one side of the pivot if desired. The friction mechanism includes first (inner) friction plates 38, 38a mounted about the hinge pin 22 on either side of the tow bar 10. The friction mechanism further includes second (outer) friction plates 40, 40a mounted about the hinge pin 22 on either side of the first (inner) friction plates 38, 38a. The inner plates 38, 38a are rigidly fastened to the second tow bar portion 14 and the outer plates 40, 40a are rigidly fastened to the first tow bar portion 12.

To exert force between the friction plates 38, 38a; 40, 40a, a spring assembly is mounted to each end of the hinge pin 22 to provide an adjustable spring bias. Two spring assemblies are preferred i.e. one at either end of the hinge pin 22, but using just one would suffice. Each assembly includes a spring 42, 42a held between two washers 44, 44a. Each nut 24, 24a holds each spring assembly onto the hinge pin 22. Each spring 42, 42a is compressed onto the hinge pin 22 by threading each nut 24, 24a onto each end of the hinge pin 22. Each compressed spring 42, 42a exerts a force against its neighbouring friction plates, preventing the tow bar 10 from swinging unexpectedly. The degree of tightness to which each nut 24, 24a is threaded onto the hinge pin 22 controls the damping force on the friction plates, and hence the force required to fold the tow bar 10.

Each of the first plates 38, 38a is semi-circular in shape. Each plate 38, 38a has one central aperture and three outer apertures. Each central aperture is disposed centrally adjacent the flat edge of each semi-circular plate 38, 38a. Each outer aperture is disposed radially outwards from the central aperture on each plate 38, 38a, the outer apertures being spaced at 90° intervals around the edge of the relevant plate.

Each of the second plates 40, 40a is roughly triangular in shape. Each plate 40, 40a has rounded corners for safety and an outwardly curved hypotenuse when viewed by its cross-section. Each plate 40, 40a has a central aperture and two outer apertures. Each central aperture is disposed near the corner opposite the hypotenuse for mounting to the hinge pin 22. On each plate 40, 40a the outer apertures are located near the two remaining corners. Each second plate 40, 40a is held to the first tow bar portion 12 by the hinge pin 22 extending through the central aperture, and the latch pin 28 extending through one of the outer apertures of the plate 40, 40a.

One of the second plates 40 has a detent plunger mounted on its outermost surface.

The detent plunger has a detent 46 to engage co-aligned outer apertures in one pair of adjacent first and second plates 38, 40, and a plunger 48 to retract the detent 46. The detent plunger is mounted so that its detent 46 is permanently aligned with one of the outer apertures in the relevant second plate 40. The plunger 48 includes a spring-loaded mechanism to re-engage the detent 46 with the relevant aperture of the inner plate 38 once the plunger 48 is released from a retracted position.

In use, the foldable tow bar 10 is initially stored in a folded configuration of minimal length, as seen in Figure 3. The pivotal connection 16 is disposed centrally between the tow bar portions 12, 14 so that the folded arrangement is substantially half of the maximum length of the in-line arrangement.

To open the tow bar 10, the detent plunger is pulled and held laterally away from the tow bar 10. This disengages the detent 46 from at least the outer aperture in the first plates 38, and may also disengage the detent 46 from the outer aperture in the second plate 40. The first tow bar portion 12 is therefore able to rotate relative to the second tow bar portion 14. The friction mechanism acts against free rotation of the tow bar portions 12, 14 relative to one another to prevent it swinging freely.

Whilst the detent plunger is still held, the first tow bar portion 12 is moved about the pivotal connection 16 in the direction of arrow A, relative to the second tow bar portion 14. Unfolding the tow bar 10 causes the portions 12, 14 to approach an in-line (i.e. 180°) configuration, i.e. the tow bar portions 12, 14 become substantially collinear. As the tow bar portions 12, 14 approach collinearity, the keeper 30 bears against the hook 34 of the spring-loaded latch, rotating the latch about the latch pin 28. Further unfolding causes the hook 34 to slip past the inner edge of the keeper 30 and latch onto it, securing the latch as the spring-loaded mechanism returns the latch to its original orientation.

The detent plunger then further locks the tow bar 10 in position once released from a retracted position. With the outer apertures positioned as described, the detent 46 can re-engage the relevant outer aperture(s) when the first portion 12 has been angularly displaced by either 90° or 180° from its starting position, as measured relative to the second portion 14. This allows the tow bar 10 to lock into a folded 0° arrangement for storage, an open 180° arrangement for use when towing, and a support 90° arrangement to provide a stable platform for a towed trailer (in conjunction with the trailer's two wheels) when stationary. These angles correspond to the angle of one tow bar portion relative to the other through the pivotal connection 16. Other embodiments are envisaged with different numbers of apertures, or alternatively with a continuous curved aperture (or slot) which can be used to lock the tow bar 10 at any angle between 0° and 180°.

After use in towing, the tow bar 10 can be disengaged from a towing vehicle and used as a stabiliser for a stationary two-wheeled trailer. To fold the tow bar 10 for such use, the detent plunger is pulled away from the tow bar 10, and the latch is levered away from the keeper 30. When both the detent plunger and latch are disengaged, the first tow bar portion 12 can be rotated relative to the second tow bar portion 12, in the reverse direction to arrow A. After a 90° rotation, the tow bar 10 forms a support leg, locking into place when the detent plunger is released to engage outer apertures in the plates 38, 40. Alternatively, the tow bar 10 may be completely folded as in Figure 3. The latch cannot engage the keeper 30 in the support leg arrangement, but the detent 46 is robust to bear the weight of a trailer acting through the plates 38, 40 against it. The detent 46 may be made from a tough, high strength metal or alloy. To bear particularly heavy loads, a second detent plunger may be included in an equivalent position on the other second plate 40a.

Referring now to Figures 4 and 5, an alternative pivotal connection for use in a second embodiment of a foldable tow bar is indicated generally at 110. This pivotal connection 110 is a geared pivot assembly including a first geared portion 112 mounted to the first tow bar portion (not shown) and a second opposing geared portion 114 mounted to the second tow bar portion (not shown).

The geared portions 112, 114 each include two laterally spaced gears, which are in mesh with the two laterally spaced gears of the opposing gear portion. Each gear is formed as a partial cog, with a central aperture for mounting the cog about a pivot pin 116, 118. The axis of each central aperture and pivot pin 116, 118 runs substantially perpendicularly to the longitudinal axis of the tow bar.

Each gear has teeth milled around a portion of its circumference. The toothed portion of each gear extends through an angle of approximately 120°, although this may vary in other embodiments. The teeth on each gear of the first geared portion 112 complement the positions of the teeth on each gear of the second geared portion 114 when the geared pivot 110 is assembled. The teeth of opposing gears mesh together in use, bearing against each other during folding and opening of the tow bar and controlling the relative positions of the geared portions.

Each geared portion 112, 114 is pivotally mounted to an end of a spacer element 120 at the respective pivots 116, 118. The pivots are mounted through apertures in the spacer element 120. The spacer element 120 is roughly cuboidal with rounded ends, and is sized and shaped to fit between the gears on each geared portion 112, 114.

By providing two spaced pivot axes, there is no need to offset a pivot axis to one side of the tow bar as in the first embodiment described, but rather, the geared portions 112, 114 can lie substantially within the cross section of the tow bar, whilst still being able to rotate through 180 degrees at the connection, i.e. 90 degrees each.

The geared pivot assembly H 0 has a spring-loaded latch (spring-loaded mechanism not shown for clarity) to lock the geared portions 112, 114 in an unfolded arrangement. The latch is similar to that of the first embodiment.

The first geared portion 112 has a bracket 122 disposed above its gears. The bracket 122 includes two spaced vertical supports, with lateral apertures near the end of each support. The latch has a body 124 with a lateral aperture running horizontally from side to side. The body 124 is mounted to the bracket 122 about its aperture by a latch hinge pin 126. The latch hinge pin 126 may extend laterally beyond the edges of the bracket (not shown), where an externally mounted friction mechanism (not shown) is provided, to engage friction plates in a manner similar to that in the first embodiment.

The second geared portion 114 has a keeper 128 opposite the bracket 122 in the open configuration of the pivotal connection 110. The latch includes a hook 130 to automatically latch onto the keeper 128 when the geared pivot is fully unfolded. The latch also includes a lever 132 to tilt the latch about the latch hinge pin 126. This releases the hook 130 from the keeper 128 when folding the pivot assembly. The latch returns to its default sprung position when no force is applied to the lever 132.

The geared hinge assembly 110 further includes a friction mechanism (not shown), such as that described above with respect to the first embodiment, including a pair of friction plates, held against one another by an adjustable spring bias. The friction mechanism may be provided externally at one or both ends of either or both hinge pins 116, 118.

In use, the operation of the geared pivot and latch of the foldable tow bar are similar to the operation of the single pivot connection described. The second embodiment brings the advantage of pivoting within the cross section of the tow bar, whilst the first embodiment with a single hinge position, requires the axis of the pivot point to be displaced to one side of the tow bar.

Features described for a foldable tow bar with a single pivot hinge may also be provided on a foldable tow bar with a geared pivot, including but not limited to one or more detent plungers to prevent rotation of the geared hinge. This may be achieved by insertion of a portion of the or each detent plunger between the teeth of two meshed gears, for example. Other embodiments of friction mechanism are also envisaged within the scope of the claims, and should not be construed as limited to the specific examples described herein.

In a further embodiment, not shown, meshing gears could be provided centrally of the tow bar ends and the spacer provided by two links on either side of the meshing gears.

The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.

Claims

CLAIMS 1.
2.
3.
4.
5.
6.A foldable tow bar for connecting a carriage to a cycling device comprising a first tow bar portion, a second tow bar portion and a pivotal connection between the first and second tow bar portions, the first and second tow bar portions being movable relative to one another about the pivot between a substantially in-line position and a folded position, the pivotal connection including a spring-loaded latch adapted to automatically engage when the first and second tow bar portions are moved from the folded position to the substantially in-line position, and a spring-loaded friction mechanism to impede rotation of the tow bar portions relative to one another about the pivot when the latch is disengaged.

A foldable tow bar as claimed in claim 1, in which the friction mechanism is provided on at least one side of the pivotal connection, and includes first and second friction plates held against one another by an adjustable spring bias, the first plate being rigidly fastened to one of the tow bar portions, and the second plate being rigidly fastened to the other of the tow bar portions.

A foldable tow bar as claimed in claim 2, in which the adjustable spring bias includes a spring, at least one force transfer element, and a nut, each provided on at least one side of the pivotal connection.

A foldable tow bar as claimed in claim 3, in which each spring is disposed between two force transfer elements.

A foldable tow bar as claimed in any of claims 1 to 4, in which the spring-loaded latch is disposed to one side of the pivotal connection and is engageable with a keeper disposed to the other side of the pivotal connection.

A foldable tow bar as claimed in claim 5, in which the latch includes a latch pin mounted through a bracket on the first tow bar portion, a body mounted about the latch pin, a hook adapted to engage the keeper, and a lever to tilt the latch about the latch pin, releasably engaging the hook with the keeper.
7. A foldable tow bar as claimed in any preceding claim, in which the pivotal connection includes at least one hinge pin, and hinge pin supports on each of the first and second tow bar portions, the or each hinge pin locating through the hinge pin supports to hingedly connect the tow bar portions.
8. A foldable tow bar as claimed in claim 7, when dependent on claim 2, in which the first and second friction plates each have a primary aperture to mount to the hinge pin, and one or more outer apertures spaced at intervals circumferentially around their edge.
9. A foldable tow bar as claimed in claim 8, in which a detent plunger is provided on the second friction plate, the detent plunger being fixedly aligned with one of the outer apertures through the second friction plate.
10. A foldable tow bar as claimed in claim 8 or 9, in which outer apertures of the first and second friction plates align by rotation of the first friction plate about the hinge pin, enabling the detent plunger to engage a pair of co-aligned outer apertures and substantially lock the pivotal connection.
11. A foldable tow bar as claimed in claim 9 or 10, in which the detent plunger is spring-loaded.
12. A foldable tow bar as claimed in any of claims 7 to 11, in which the outer apertures of each friction plate are spaced at intervals of 90°.
13. A foldable tow bar as claimed in any of claims 7 to 12, in which the second friction plate extends towards the latch more than the first friction plate.
14. A foldable tow bar as claimed in any of claims 7 to 13, when dependent on claim 6, in which the latch pin extends through one of the outer apertures in the second friction plate.
15. A foldable tow bar as claimed in any of claims 7 to 14, in which the pivotal connection includes a first geared portion pivotally mounted to a spacer element about a first pivot, a second geared portion mounted to the other end of the spacer element about a second pivot, the first and second geared portions being meshed together.
16. A foldable tow bar as claimed in claim 15, in which each geared portion includes one or more gears, each gear having teeth around substantially at least one quarter of its circumference.
17. A foldable tow bar as claimed in claim 15 or 16, when dependent on claim 5, in which the latch is mounted to the first geared portion and the keeper is mounted to the second geared portion, substantially preventing the gears from rotating against each other if a moment is applied when the latch is engaged with the keeper.
18. A foldable tow bar as claimed in any preceding claim, in which the friction mechanism is provided on both sides of the pivotal connection.
19. A foldable tow bar as claimed in any preceding claim, in which the tow bar includes a guard means, the guard means being securable around the tow bar to restrict physical access to the pivotal connection.
20. A foldable tow bar as claimed in any preceding claim, in which an interlock is provided to substantially prevent accidental actuation of the pivotal connection.
21. A foldable tow bar substantially as described herein, with reference to and as illustrated in Figures 1 to 3, and 4 and 5 of the accompanying drawings.