GB2372026A

GB2372026A - Vehicle tow bar

Info

Publication number: GB2372026A
Application number: GB0103580A
Authority: GB
Inventors: Richard John David Appleton; Christopher Keith Grant
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-13
Filing date: 2001-02-13
Publication date: 2002-08-14
Anticipated expiration: 2021-02-13
Also published as: GB0103580D0; GB2372026B

Abstract

A vehicle tow bar for connection between two vehicle so that one vehicle may be towed by the other comprises a bar (2, 4) having coupling means (6, 9) at each end. A swivel joint allows the coupling means to rotate with respect to each other along the major axis of the bar. The bar (2, 4) consists of telescopic members which are movable with respect to each other so that the bar is adjustable in length and there are lock means to fix the telescopic members in an extended position.

Description

VEHICLE TOW BAR This invention relates to a vehicle tow bar. It relates particularly to a tow bar of a rigid construction which is capable of forming a direct mechanical linkage between two motor vehicles for towing purposes.

The kind of tow bar available at present is usually designed for coupling together vehicles of a particular type or small group, for example those produced by one manufacturer. If one wishes to be able to tow any one of a larger group of vehicles then it is usually necesary to use a tow rope or tow strap conection which is very adaptable but which gives a non-rigid linkage and thus requires extreme care if J t is to be used in safety.

One solution to this problem has ben proposed in Patent Application Ko.

GB9811785 which discloses a rigid tow bar having a two part construction.

When using a rigid tow bar, this has of course a predetermined length since it is required to hold the towing and the towed vehicles a fixed distance apart froc ogle another. The procedure of coupling the two vehicles together begins, for example, by connecting one end of the tow bar to the front end of the vehicle to be towed. The tree end of the tow bar is then placed on the ground surface and the towing vehicle is backed up close to this free end. It is then necesary to secure the free end of the tow bar to a towing point on the rear end of the towing vehicle. Usually, it will be found that the backing up of the towing vehicle was not effected very precisely on the first attempt and a small further movement of a few inches may still be needed before t le tow bar linkage can be attached to the towing point.

When there is only a single driver available to carry out the towing operation. this driver will have to look at the closeness of the towing point to the tow bar linkage

will then need to be and then return to the towing vehicle cab. The towing vehicle will then need to be moved forward or backward a few inches so that the towing point wil be brought into the correct position for enabling the tow bar linkage to be coupled to it. The rigid nature of the tow bar requires that this distance is closely defined so that a precise positioning of the two vehicles is necessary. In achieving this relative positioning or the vehicles it may not be possible or practicable to move the vehicle requiring to be towed in order to make the task easier. If the two vehicles are situated on a non-level ground surface the problems are likely to be increased.

The task of connecting the tow bar is also likely to require great care on the part of the towing vehicle driver in order to avoid any bruising or accidental damage to the driver's hands. Heavy duty gloves should, of course, be worn.

It is clear that the rigid nature of the tow bar and the rigid connection pieces that are located at the bar ends demand a very precise positioning of the two vehicles with respect to one another before the bar can be properly coupled up. A tolerance of only a fraction of an inch is all that such a connection arrangement will tolerate.

It would be easier if the connections to the two vehicles could be made by means that allowed some variation in the spacing distance between the two vehicles.

According to the invention, there is provided a vehicle tow bar for connection between two vehicles such that one can be enabled to tow the other, the bar comprising a rigid pole having coupling means at each end to enable the ends to be connected respectively to any one of a towing bracket, a coupling, an eyelet or a yoke. and a swivel joint connected to allow a full rotation of the pole mounting means about the pole major axis, in which the rigid bar has one end which is able to be moved longitudinally of the pole major axis so that the pole length may be adjusted, and locking means effective to hold the pole length in its extended position.

Conveniently, the pole length comprises a first pole portion and a second pole portion which is supported substantially parallel to said first portion. The second pole portion may be located at the side of the first portion. Preferably. the second pole portion is arranged to slide within the said first portion to form a telescoping arrangement.

The first and second pole portions may be provided with stop means so that the two portions will be positively secured together. The stop means may be attached to both the pole portions so that a permanent fixing will be made.

The tow bar may comprise an outer pole portion which supports an inner pole portion which is arranged to slide telescopically within the said outer portion. One or both of the pole portions may be provided with stop means effective to prevent the inner pole portion from being completely separated from the said outer portion. One stop means may be a collar which is secured internally to one end of the outer pole portion. A further stop means may be a second collar which is secured externally to one end of the inner pole portion. A lock means may be provided by a nut and bolt fixing the bolt part of which is passed through a bolt hole in the outer pole portion.

By way of example, a particular embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of the tow pole in a retracted condition for storage, Figure 2 is a similar view of the pole in an extended condition for putting into use.

Figure 3 is a view from above of the Figure 2 pole, Figure 4 is an enlarged view of the left hand end of the pole of Figure 2 with some vehicle connection brackets, Figure 5 is a similar view of the right hand end of the Figure 2 pole including a yoke connection bracket which is mounted thereon, Figure 6 is a view partly in cross-section of the midpoint of the Figure 2 pole. Figure 7 is a cross-sectional view of the right hand end of the first pole portion with internally fitted collar, and, Figure 8 is a cross-sectional view of the left hand end of the second pole portion with a collar externally secured thereon.

As depicted in Figure 1, the vehicle tow bar 1 when in its out of use condition for storage forms a compact package which is easily capable of being stored in the boot compartment of a family car. The tow bar 1 is formed of an outer pole portion 2 which supports a connection bracket mounting tube 3 at its left hand end. The outer pole portion 2 encloses an inner pole portion 4 which extends partially beyond the rght hand end of the outer portion. The inner pole portion 4 is supported in a telescopic type of mounting relative to the outer portion so that the inner portion may be pulled outwards from the outer portion. This arrangement allows the overall length of the tow bar 1 to be extended by about a third. When intended to be put into use, the tow bar 1 may be removed from the boot compartment and the two ends of the bar pulled apart from one another such that the unit is caused to extend telescopically.

The ow bar then is in the form shown in Figures 2 and 3. The inner portion part of the bar is prevented from being pulled completely away from the outer portion by an internally fitted stop.

Figure 4 is an end view in perspective of the left hand end of the Figure 2 pole.

The connection bracket mounting tube 3 is provided with two mounting holes 6 which are spaced longitudinally along the pole axis and which have axes which are located at right angles to one another. These mounting holes 6 are used for securing a suitable vehicle connection bracket to the mounting tube 3. Figure 4 also shows two suitable connection brackets, a bracket 7 for a ball hitch and a towing eye 8. The appropriate chosen bracket may be secured by fastenings through the mounting holes 6 when the pole is required to be fitted to whatever coupling may be installed on the vehicle for towing.

Figure 5 shows a yoke connection bracket 9 which is permanently attached to the right hand end of the inner pole portion 4. The yoke connection bracket 9 has an opening to which may be secured one of a small range of mounting brackets which is provided with the tow bar. By this means, the pole right hand end may be given the correct attachment for enabling it to be secured to the vehicle intended for a towing operation.

Figure 6 shows the joint between the inner and outer pole portions in the middle region of the tow bar 1 when this is in the extended condition. The outer pole portion 2 is provided with a collar 11 fitted internally at its right hand end and the collar 11 fits closely round the outer surface of the inner pole portion 4. The inner pole portion is thus enabled to be pushed by sliding it within the outer pole portion 2 or to be withdrawn almost completely from the outer portion. To prevent the inner pole portion 4 from being completely withdrawn, the inner portion at its left hand end carries ts own collar 12. The mechanical clearances are such that the collar 12 on the inner portion 4 allows the inner portion to be slid freely in and out of the outer portion 2, however, the collar 12 serves to prevent the inner portion 4 from being completely withdrawn from the outer portion 2.

The outer portion also includes a bolt hole 13 which is arranged to lie just outside the end of the inner portion 4 when the inner portion has been fully extended.

The vehicle tow bar 1 is additionally provided with a bolt and nut fixing (not shown) which may be secured throught this bolt hole 13 when required. In a prototype construction, the bolts and nuts provided were of a 8.8 high tensile steel material.

When the tow bar is intended to be used for a towing operation and the bar inner portion 4 has been fully extended from the outer portion 2, the bolt and nut may be secured in the bolt hole 13. This means will therefore prevent the tow bar inner portion 4 from being pushed back into the outer portion 2. The tow bar will thus be held in the fully extended condition to allow the bar to be used safely for a towing operation.

Figure 7 shows a detail of the outer pole portion 2 with its internally fitted collar 11. Figure 8 similarly shows the inner pole portion 4 with its externally fitted collar 12.

In construction of the vehicle tow bar, this was made throughout of a suitable high tensile steel material. In one prototype construction, this was of an EN3 grade steel. The connection brackets for the tow bar ends were of stainless steel castings.

The joints between the different bar parts were effected by welding operations and the collars 11,12 were secured to the inner and outer portions also by welding. The fixing of the collar 11 to the outer portion 2 was, of course, undertaken after the inner portion 4 with its own welded collar 12 had been inserted into the outer portion.

In use of the vehicle tow bar, when it is required to carry out a towing operation, the two vehicles are brought to within, say, three to five feet of one another.

The tow bar is arranged with a selected bracket mounted on its left hand end so that it may be connected to the vehicle to be towed. All modem vehicles are provided with their wn towing eyes so that the most suitable connectioon for a given vehicle can be quickly found from among the small range of brackets provided with the tow bar.

Whilst the tow bar is still in a retracted or partially retracted condition, the right hand end of the bar is similarly connected to the vehicle for carrying out the towing operation. The relative spacing between the two vehicles is not too critical at this stage because the tow bar can be extended a short distance telescopically in order to enable the linkage to be made. The construction of the tow bar enables one end of the bar to be rotated with respect to the other end and this property makes it easier for the connections to the two vehicles to be coupled up. The towing vehicle is then driven or pushed a short distance until the tow bar becomes fully extended. If the towing vehicle is being moved under its own power at this moment, the point when the collars 11,12 on the inner and outer portions come into contact will be readily detected because of the increased driving load that will be noticed at this moment.

The tow bar will then be in its fully extended state and it is locked in this position by inserting the separate bolt through the bolt hole 13 adjacent the inner pole portion 4 end and securing the bolt in this position by means of the nut provided.

The tow bar will thus have become locked in its fully extended condition between the two vehicles so that the proposed towing operation can be carried out in safety. The bar will serve to prevent the towed vehicle from coming into contact with the rear of the towing vehicle. Due care should of course be taken in the driving of the towing vehicle because of the increased loads that will be present under acceleration and braking forces. The tow bar has been found to give increased safety in use when the connections between the two vehicles are made on an uneven. a sloping or an inclined road surface.

After use of the tow bar, it may be disconnected from the two vehicles and the bolt and nut fixing removed from the bolt hole 13. The tow bar outer and inner portions may then be slid together so that the bar will be returned to its conpact shorter form for storage. The vehicle tow bar has been found to provide a lightweight and robust motor

accessory which combines good mechanical strength with a comparative ease of cal manufacture. Prototype tow bar constructions have been found able to comply with product safety requirements which are accepted as standard by the usual automotive industry manufacturers. It is expected, in the future, that in order for a tow bar to receive appropriate certification the bar will have to be of at least two metres in length. This requirement can be met very readily with the tow bar construction of the present invention. The tow bar is suitable to be used with many types of vehicles. and it is able to be used in places where entry or exit is only possible for vehicles having a comparatively low roof height. It can thus be used in some places where a conventional garage towing truck would not have access.

The foregoing description of an embodiment of the invention has been given by way of example only and a number of modifications may be made without departing from the scope of the invention as defined in the appended claims. For instance, it is not essential that the tow bar construction should have just two sliding portions and in a different embodiment it could be made with three sliding portions.

Furthermore, instead of the connection bracket mounting tube 3 being secured to the outer pole portion 2 by a welded joint, in an alternative construction the tube 3 could be attached by a nut and bolt fixing. This arrangement would then allow the tube : ; to be removed from the assembled tow bar if necessary to allow maintenance or repairs and adjustments to be made.

The nut and bolt fixing intended for the hole 13 could of course be replaced by a blocking pin provided with a cross drilling such that a cotter pin can be passed therethrough to prevent loosening under vibration. This will serve similarly to hold the pole in the fully extended condition.

Claims

CLAIMS 1 A vehicle tow bar for connection between two vehicles such that one can be enabled to tow the other, the bar comprising a rigid pole having coupling means at each end to enable the ends to be connected respectively to any one of a towing bracket, a coupling, an eyelet or a yoke, and a swivel joint connected to allow a full rotation of the pole mounting means about the pole major axis, in which the bar has one end which is able to be moved longitudinally of the pole major axis so that the pole length may be adjusted, and lock means effective to hold the pole length in its extended position.
2 A tow bar as claimed in Claim 1, in which the pole length comprises a first pole portion and a second pole portion which is supported substantially parallel to said first portion.
3 A tow bar as claimed in Claim 2, in which the said second portion is arranged to slide within the said first portion to form a telescoping arrangement.
4 A tow bar as claimed in Claim 3, in which the first and second pole portions are provided with stop means effective to retain the two portions together.
5 A tow bar as claimed in Claim 4, in which the stop means comprises a first collar which is secured internally to an outer pole portion and a second collar which is secured externally to an inner pole portion.
6 A tow bar as claimed in any one of Claims 1 to 5, in which the lock means comprises a removable fixing capable of being positioned when the pole length has been adjusted to its extended postion.
7 A tow bar as claimed in Claim 6, in which the lock means comprises a nut and bolt fixing, the bolt part of which is capable of being secured in a bolt hole in said bar.
8 A vehicle tow bar substantially as hereinbefore described, with reference to any one of the accompanying drawings.