WO1992020540A1

WO1992020540A1 - Towbar

Info

Publication number: WO1992020540A1
Application number: PCT/GB1992/000851
Authority: WO
Inventors: Graham Woodruff
Original assignee: Graham Woodruff
Priority date: 1991-05-13
Filing date: 1992-05-12
Publication date: 1992-11-26
Also published as: CA2102690A1; EP0584150A1

Abstract

A towbar is disclosed comprising a plurality of sections which lock together to form a single length, the two sections at opposite ends of the assembled towbar having couplings to attach to respective vehicles and the adjoining ends of adjacent assembled sections each comprising a connecting member, one male (1; 20) and one female (2; 21), one of the connecting members including a locking member (5; 26) which locks the male connecting member within the female connecting member.

Description

Towbar

The present invention relates to a towbar and more specifically to a portable rigid towbar which may be assembled from multiple lockable sections.

Rigid towbars used by towing vehicles are generally long, heavy items, which are difficult to store. For a reduction in length rigid towbars may be provided in two sections, the sections being coupled together when in use. Smaller vehicles used for occasional towing, such as in an emergency, often use flexible towropes of rope or wire. The flexible type of towrope has a clear advantage for the motorist in that it is eas ly portable and can be conveniently stored in the vehicle. However, whilst the flexible towrope is convenient for storage, its towing performance is inferior to that of a rigid bar (particularly when the towing vehicle is braking). It would therefore be desirable to have a rigid towbar with the portability of a towrope. This would be especially useful to such as four wheel drive vehicles which may be required for towing, but which are generally used as all purpose vehicles, so that storage of a conventional towbar would not be practical .

The present invention provides a towbar comprising a plurality of sections which lock together to form a single length, the two sections at opposite ends of the assembled towbar having couplings to attach to respective vehicles and the adjoining ends of adjacent assembled sections each comprising a connecting member, one male and one female, one of the connecting members includes a locking member which locks the male connecting member within the female connecting member.

Adjacent sections may be locked together using a bayonet type fitting whereby the male end is inserted into the female end, projections on the male end being located into slots in the female end, and twisted relative to the female end. The twisting motion causes each projection on the male end to pass into a locking part of the slot and the locking member engages behind one or each projection to prevent twisting in an opposite direction.

Alternatively sections may be locked together using a fitting whereby the male end is inserted into the female end a bolt is placed through matching holes in both sections.

Each section may comprise a plurality of tubular members of substantially the same length fitted within one another but displaced axial!y with respect to one another and preferably connected to one another by means such as a rivet, welding, adhesive of crimping.

Preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which:

Figure 1 is a perspective view of adjoining ends of sections of a towbar before assembly according to a first embodiment of the invention;

Figure 2 is a part axial section of the parts shown in Figure 1 ;

Figure 3 is a transverse section on line B...B of Figure 1 but with the sections assembled;

Figure 4 is a perspective view of a towbar section according to a second embodiment of the invention; Figure 5 is a perspective view of one example of coupling; and

Figure 6 is a plan view of an assembled towbar made up of 5 sections as shown in Figure 4.

A towbar is provided comprising a plurality of sections which lock together to form a single length, the two sections at opposite ends of the assembled towbar having couplings to attach to respective vehicles.

Figure 1 shows the male and female ends (1,2) of two adjacent towbar sections. Each towbar section has a female end (1) and a male end (2). Female end (1) comprises a collar (3) which is permanently connected ( e.g. by welding ) onto one end of the tubular steel towbar section (4a) and a locking member (6). The collar (3) has two similar shaped slots (5) positioned 180 degrees apart. The slots are L shaped having an entry part (5a) parallel to the axis and a locking part (5b) extending transversely to the axis connected by a 90 degree corner. The Male end (2) of adjacent towbar section (4b) includes projections (13) which protrude oppositely from the towbar section (4b). In practice the projections (13) may be provided by a pin which fits through opposed holes in the towbar section (4b) and protrudes at both sides of the towbar section (4b). The locking member (6) which is shown in more detail in figure 2, comprises a locking pin (7) suitably mounted in a tubular member (10), a resilient member in the form of a spring (8) and release catch (9). The locking member is shown as positioned within the towbar section (4a), however, it may also be positioned on the outside of the towbar section (4a). The locking pin (7) is resiliently urged to an extended position by the spring (8). Retraction of the locking pin is achieved by movement of the release catch in a direction so as to compress the spring.

In use multiple sections are locked together by insertion of a male end into a female end and twisting the male end whilst the locking pin is retracted. Thus each projection

(13) passes along the entry part (5a) of the respective slot (5), engages the locking pin (7) causing it to retract, and the twisting motion causes the projection (13) to pass into the locking part (5b) of the slot (5). The locking pin (7) is released and is thereby extended into its extended position in which it closes off the locking part (5a) of the slot (5), locking the projection on the male end into the slot.

When multiple sections are attached in this way they form a rigid bar. The two sections on either end of the towbar have a coupling on their unconnected end, the coupling being suitable for joining to the respective vehicles.

The couplings may be flexible and may comprise a ball and socket joint.

To release the sections the locking pin must be retracted by pulling on the release catch and the male end twisted and pulled in the opposite direction.

The overall length of the towbar may be approximately 2.5 metres, made up of 6 sections each of approximatel 0.42 metres. The sections are not necessarily of equal length, although this is desirable for ease of storage. The collars (3) may be made from tubular steel or aluminium and the tubular towbar sections may be formed from steel or aluminium of lesser diameter. The collars may be joined onto the tubular towbar sections using a welding technique such as friction welding.

Figure 4 shows a towbar section of a second embodiment of the invention with a male end (20) and female end (21). The section comprises three tubular subsections (22,23,24) which are each of the same length but of different cross sectional areas. Although the cross section is shown as square it may equally be round. The three tubular subsections are positioned so that the tubular subsection of smallest cross section (22) is partially inside the tubular subsection of next largest cross section (23) which is in turn positioned partially inside the tubular subsection of largest cross section (24). The outside cross-section of each tubular subsection is substantially the same as the inside cross-section of the next largest tubular subsection so that they are a snug fit within each other. Two thirds of the length of each of the two tubular subsections is inside its next largest tubular subsection. The three tubular subsections which make up one section which may be, for example of steel or aluminium are permanently fixed together using rivets (25) or any other suitable fixing such as welding (at the exposed cut edges of the tubular subsections), adhesive, or crimping.

In use, two sections are locked together by placing bolts (not shown) through aligned bolt holes (26) in the outer tubular subsection of the first section and the inner two tubular subsection of the second section thereby securing a male end 20 of the second section within a female end (21) of the first section. By locking all of the sections together in this way, a towbar may be assembled which is made up of multiple sections. The two sections on either end of the towbar have a coupling (see for example coupling 27 in figure 5) on their unconnected end, the coupling being suitable for joining to the respective vehicles.

To release the sections the bolts must be removed from bolt holes (26).

Claims

1. A towbar comprising a plurality of sections which lock together to form a single length, the two sections at opposite ends of the assembled towbar having couplings to attach to respective vehicles and the adjoining ends of adjacent assembled sections each comprising a connecting member, one male (1;20) and one female (2;21), one of the connecting members including a locking member (5;26) which locks the male connecting member within the female connecting member.

2. A towbar as claimed in claim 1 characterised in that adjacent sections are locked together using a bayonet type fitting whereby the male end is inserted into the female end, projections (13) on the male end being located into slots (5) in the female end, and twisted relative to the female end, the twisting motion causing each projection on the male end to pass into a locking part (5b) of the slot and the locking member engaging behind one or each projection to prevent twisting in an opposite direction.

3. A towbar as claimed in claim 1 characterised in that adjacent sections are locked together using a fitting whereby the male end is inserted into the female end, and a bolt is placed through matching holes (L6) in both sections.

4. A towbar as claimed in claim 3, characterised in that each section comprises a plurality of tubular members of substantially the same length fitted within one another but displaced axial ly with respect to one another.

5. A towbar as claimed in claim 4 characterised in that the sections are connected to one another by means such as a rivet, welding, adhesive or crimping.