This invention relates to a docking aid for use when lining up a trailer to a vehicle for transport elsewhere.

Coupling up a car with a caravan or boat trailer is a difficult manoeuvre. The car is fitted at the rear with a tow-ball which must be correctly aligned with the tow hitch of the trailer in order to dock properly. The usual procedure adopted to achieve this is that the car is reversed approximately into place, usually with the aid of a person outside the car. Once the car is as near as possible to the trailer, the tow-ball and tow-hitch are manhandled into contact with each other.

This is an awkward operation, and very unsatisfactory for holiday-makers who may be less able, or for the elderly, who are increasingly turning to caravanning holidays for their vacations.

According to the present invention there is provided a docking aid for use with a vehicle and trailer, comprising, first and second indicator assemblies each comprising an attachment means and a visible indicator

means; the first indicator assembly being mounted, in use, on the vehicle by its attachment means such that its visible indicator means indicates the position of the vehicle tow-ball; and the second indicator assembly being positioned, in use, on or adjacent the trailer by its attachment means such that its visible indicator means indicates the position of the trailer tow-hitch; both visible indicator means being visible, in use, to a driver in the vehicle.

The visible indicator means is preferably a rod which is long enough to be visible from the vehicle. The rod may be dismantled into smaller stowable sections or may be one continuous piece.

The attachment means has housing means for said indicator means; in the case of a rod, the housing means may be a socket. The socket may be grooved to match corresponding keys, which are provided by the rod. Alternatively other methods of securing the indicator means to the housing means may be provided.

The docking aid may be attached in the required position by the provision of magnets or the gripping action of a spring-biassed pincer means. These methods of attachment allow the docking aid to be removably attached to existing ball-and-hitch units.

Alternatively, the attachment means may be manufactured with the housing means as an integral part of the tow-ball and/or the tow-hitch; and the housing means may be integral with the attachment means or provided as a discrete unit to be fitted in place.

A further method of providing attachment means is to use a plate which is positioned about or underneath the tow-ball, and which has connective means for the housing means or has the housing means as an integral part of the plate. Markings on the indicator means may also be provided to mark the heights of the ball and the hitch, and so enable correct spatial alignment between the two.

Embodiments of the invention will now be described by way of example with reference to the drawings in which:

Fig. 1 shows a first embodiment of a docking aid of the present invention attached to a tow-ball; Figs. 2 and 3 show parts of the docking aid of Fig. 1 in more detail; Fig. 3A is a plan view of a section on A-A of Fig. 3; Fig. 4 is a perspective view of a second embodiment of a docking aid of the present invention; Fig. 5 shows the docking aid of Fig. 4 attached to a tow-hitch handle; Fig. 6 is a perspective view of a third embodiment of the invention; Fig. 7 shows a fourth embodiment of the invention; Figs. 8A + B, 9A + B, 10A + B and 11A + B are front and side views respectively of examples of the different type of hitch used with the present invention; Fig. 12 shows a fifth embodiment of the docking aid of the present invention; and Fig. 13A and B shows a spring-locating attachment means which can be used in all types of hitch.

Referring to Figs. 1-3A, docking aid comprises a grip 2 and socket 3 which houses a rod 4. The socket 3 is secured against the grip 2 using a screw arrangement 5. The rod 4 is angled, so that when in the correct position in the socket 3 it is aligned with the position of the tow-ball 6 of a car (not shown). The rod 4 is located on the socket 3 by means of keys 7 which correspond to grooves 8 on the socket 3 so as to correctly align the rod 4 with the tow-ball 6. The grip 2 is shown in plan view in Fig. 2. The arms 9 of the grip 2 are squeezed together against the spring 10 to open the aperture 11 which may then be fitted about the ball 6.

A second embodiment of the docking aid of the present invention is shown in Figs. 4 an 5 where similar parts are numbered as in Fig. 1 + 100. In this docking aid 101 the rod 104 is not angled and is placed by means of a socket 103 directly above a tow-hitch 14 of a trailer (not shown). The socket 103 is held in position on the tow-hitch 14 by means of a magnet 12 placed against the lifting handle 13 of the tow-hitch 14.

The tow-hitch 14 can alternatively be indicated in a similar manner to the tow-ball 6 of Fig. 1, using a grip 2 an an angled rod 4.

In use, the docking aid 1 is erected on the tow-ball 6 of a car, and either the docking aid 101 or 1 is erected on the tow-hitch 14 of the trailer, and the ball 6 and hitch 14 are guided into position by reversing the car so that the two rods 4 and 104 are lined up. To ensure that the trailer tow-hitch 14 is aligned in the correct spatial arrangement relative to the tow-ball 6, ie that the tow-hitch 14 is positioned

at a higher level than the ball 6, so that the ball can slot in under the hitch 14, markers 15 are provided on the rods. The car and trailer may then be docked with the minimum of fuss and effort.

Alternatively, the rod is provided as an integral part of the grip as shown in Fig. 6, where similar parts are numbered as in Fig 1 plus 200. In this embodiment a marker 215 is provided as a coloured disc which gives a check as to height against a coloured band on the caravan unit (not shown).

Fig. 7 is a fourth embodiment of the invention (similar parts are numbered as in Fig. 1 plus 300) in which the grip is provided as a tong 302 which grips the tow-hitch 314 of the towing unit. The tong 302 is shaped to clamp the edge of the hitch 314.

The tow-hitch can be cast or made of pressed steel and may have an angled handle (Figs. 8A and B) or a horizontal locking handle (Figs. 9A and B).

An alternative attachment means for the rod is shown in Fig. 13A and B. Similar parts are labelled as in Fig. 1 plus 400. A housing 403 is provided on the attachment means which are in the form of a spring-locating device 402 for attachment to the tow-hitch. Thus, in use the housing 403 is pressed down on the top surface of the steel tow-hitch and the spring-clips grip the hip of the tow-hitch 414.

Alternatively, the housing 403 could be welded to the top surface of the steel tow-hitch or, if made from pressed steel, may be an integral part of the tow-hitch as shown in Figs. 10A and B.

The rod may be in a telescopic form and permanently fixed to the tow-hitch, and a visual proximity warning device could also be fixed to the hitch.

The docking aid may be provided as a free standing unit as illustrated in Fig. 12. In this embodiment, similar parts are labelled as in Fig. 1 plus 600. The rod 604 is mounted on the hitch 615 using an adjustable attachment means 601 which comprises a pivotable housing 603 provided on an arm 16 of the attachment means 601. The arm 16 can rotate about its longitudinal axis and can also be fixed at any position on a vertical support member 17. In use, the rod 604 is aligned with the centre of the hitch 614 using the adjustable parts, and raised telescopically to be viewed at the rear of the vehicle.

The docking aid of the present invention may be provided as a kit of parts, or the grip 2 with its attachment socket 3 may be cast or welded at the same time as the tow-ball is being made, as may the socket on the grip; or the grip may be provided as a galvanised plate and socket. In this last case, the tow-ball unit is unbolted from the car and the plate placed against it, the unit is bolted back into position so securing the plate in place. The socket may be screwed into place or similarly welded on during manufacture.

An integral rod housing may be provided in the cast-iron tow-ball unit, on the neck of the ball, or a clip-on rod housing which attaches to the neck of the tow-ball may be provided. Alternatively a metal plate with one end formed in a curve to the shape of a rod housing could be provided. This would be inserted, as

is the galvanised plate and socket, before the tow-ball unit was bolted on.

A telescopic rod may be permanently attached to the tow-ball and could double as a car aerial. It may electrically raised and lowered as required.

Modifications and improvements may be incorporated without departing from the scope of the invention.