GB2416336A

GB2416336A - Vehicle towing apparatus

Info

Publication number: GB2416336A
Application number: GB0416066A
Authority: GB
Inventors: Richard Francis Rodgers
Original assignee: INTERTRADE ENGINEERING Ltd
Current assignee: RODGERS, RICHARD F
Priority date: 2004-07-17
Filing date: 2004-07-17
Publication date: 2006-01-25
Anticipated expiration: 2024-07-17
Also published as: GB2416336B; GB0416066D0

Abstract

A vehicle recovery apparatus having a drawbar (1) having an axis and two wheel units (3,4,5) mounted relative to the drawbar on opposite sides respectively of the axis of the drawbar. The wheel units are movably mounted relative to the drawbar such that they may be moved to extended and retracted positions relative to the drawbar along an axis which is generally orthogonal to the axis of the drawbar. Movement of the wheel units enables that apparatus to adopt a configuration for storage in which it requires less space than comparable conventional apparatus. This facilitates storage of the apparatus in a vehicle.

Description

24 1 6336

VEHICLE TRANSPORTATION APPARATUS

The present invention relates to vehicle transportation apparatus.

Tow dollies are two-wheeled trailers used for holding the two front or rear wheels of a vehicle relative to a recovery vehicle to aid towing. They generally comprise a drawbar that attaches at one end to the rear of the recovery vehicle and has, at its other end, a transverse axle which supports two wheeled wheel supporting platforms, one at each end of the axle. In use the front or rear wheels of a vehicle to be towed are driven or winched up ramps to rest on the wheel supporting platforms of the dolly, whilst its rear or front wheels remain on the ground. Tow dollies may either be attachable to a hitch ball or drawbar receiver mechanism of, or permanently mounted in the back of a recovery vehicle and arranged to be folded and stowed in the vehicle when not in use.

Conventional 'on-board' tow dollies, i.e. those that are mounted on a recovery vehicle, have several drawbacks. They are not particularly compact in their folded configuration. This is largely attributable to their method of operation. From a state of use, each side of the transverse axle pivots on hinge pins situated at the end of the drawbar so as to bring either side of the axle in towards the sides of the drawbar.

When retracted into the vehicle the dolly unit remains relatively bulky owing to the size of each side of the transverse axle. As such towing dollies may only be mounted in relatively large recovery vehicles Another disadvantage of current vehicle mounted tow dollies is that the operator must attend the offside or centre (between the two vehicles) of the recovery vehicle to extend the axles from their folded state so that the tow dolly may be used, thus increasing the risk of accidents involving passing traffic, or vehicles colliding with the stationary casualty vehicle.

The present invention seeks to address these issues.

According to the present invention, there is provided a vehicle recovery apparatus comprising a drawbar having an axis and two wheel units mounted relative to the drawbar on opposite sides respectively of the axis of the drawbar wherein said wheel units are moveably mounted relative to the drawbar such that they may be moved to extended and retracted positions relative to the drawbar along an axis which is generally orthogonal to the axis of the drawbar.

Enabling movement of the wheel units in a direction substantially orthogonal to the axis of the drawbar enables the apparatus to adopt a configuration for stowage in l O which it requires less space than comparable conventional vehicle mounted dollies.

Preferably the wheel units are mounted relative to the drawbar by means of an extendable member, or respective extendable members. Preferably the or each extendable member is telescopic. In one embodiment the or each extendable member comprises a main axle fixed to the drawbar and an outer axle moveable, preferably slidably moveable, relative to the main axle. Each wheel unit may be mounted on an outer axle and is preferably moveably or slidably mounted on an outer axle. A stop or stops may be provided to limit the amount of extension of the extendible member, the stop may comprise a lug or spring loaded pin.

Preferably said wheel units each comprise a wheel carrying platform and a rotatable wheel.

Preferably there is provided a driving means for driving the wheel units between the retracted and extended positions. More preferably said driving means comprises a lead screw. Preferably said lead screw is attached to the drawbar.

Preferably, said wheel units comprise lead screw nuts that are threadedly engaged with the lead screw such that the wheel units may be moved relative to the drawbar by rotating the lead screw. The lead screw may be threaded in opposite directions on either side of said drawbar respectively so that rotation of the lead screw causes the wheel units to move towards or away from each other between the retracted and extended positions.

Preferably the lead screw is operable by means of a driving nut situated at the end of the lead screw. An appropriate driving means may be provided, for example a handle or electric motor.

Any other suitable drive mean may of course be employed, for example a hydraulic drive means.

Preferably said drawbar comprises two portions pivotable relative to each other, one of said portions being attachable to and pivotable at a base to facilitate its mounting on a recovery vehicle and retraction of the towing apparatus into to the vehicle.

Preferably, said drawbar comprises means to urge the two portions of the drawbar relative to each other such that the drawbar is extended. More preferably said means comprises a resilient means, for example a gas spring.

Preferably said vehicle recovery apparatus is mounted on a vehicle. The apparatus may be a tow dolly.

In order that the invention may be more fully understood a specific embodiment will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 shows a tow dolly according to the present invention mounted in a vehicle and having been partially lowered from a vehicle with the dolly wheel units in a retracted state; Figure 2 shows the tow dolly of figure I with its wheel units in an extended state; and Figure 3 is a side on view of the drawbar of the tow dolly of Figures I and 2 mounted on the floor of the vehicle of figure 1 and in a partially lowered state.

Referring to the drawings, the tow dolly comprises a drawbar 1, a main axle 12, two slidable outer axles 2, two wheel units each defining a hollow tube 3, a wheel carrying platform 4, a rotatable wheel 5 and a lead screw nut 6.

The drawbar I comprises two elongate shafts 13, 14 connected to each other at respective ends by way of a pivot 18 enabling the shafts to pivot between an extended configuration in which the two shafts are substantially coaxial and a folded position at which the two shafts lie at an angle to each other. The end of one shaft 14 remote to the pivot 18 is pivotally mounted on the floor of a recovery vehicle 19 and a loop 21 for attachment to a winch cable is provided on the shaft 14. A winch 16 is also mounted in the recovery vehicle and a cable 20 extends from the winch to the loop 21 on shaft 14. The winch 16 is used to raise and lower the drawbar to enable the tow dolly to be retracted into and lowered from the recovery vehicle. As the drawbar is raised it will adopt its folded configuration. A gas spring 15 is disposed between the two shafts 13, 14 of the drawbar and arranged to urge the shafts of the drawbar towards the extended position as the apparatus is lowered from the recovery vehicle.

The main axle 12 comprises an elongate shaft, attached to and extending substantially orthogonally from respective opposite sides of the free end of the drawbar, so as to form a 'T' shape. The outer axles 2 are tubes of approximately the same length as the main axle 12 on either side of the drawbar I, and the hollow tube of each of the wheel units is around half the length of each outer axle. The inner diameter of the outer axles 2 is approximately the same as the outer diameter of the main axle 12 so that each outer axle unit is slidable along the main axle 12. The inner diameter of the hollow tubes 3 of each of the wheel units is approximately the same as the outer diameter of the outer axles 2 so that each wheel unit is slidable along the outer axle 2. Thus a telescopic formation is created comprising the main axle 12, the outer axle 2 and the hollow tube 3 of the wheel unit. A lug 9 is positioned at the end of the outer axle so as s to prevent the wheel units being removed from the outer axle. A lug (not shown) is also disposed on the main axle 12 to prevent the outer axle 2 being removed from the main axle 12.

Also, rotatably attached to the drawbar, substantially parallel to the main axle, is a lead screw 7 around which lead screw nuts 6 are situated such that they are threadedly engaged with the lead screw 7. A driving nut 8 is positioned at one end of the lead screw. On one side of the drawbar the lead screw is left hand threaded 10, and on the other side of the drawbar the lead screw is right hand threaded 11. The lead screw nuts 6 are attached to the wheel units so that rotation of the lead screw 7 causes the wheel units to move relative to the lead screw.

In use, and commencing from a position where the tow dolly is fully retracted within a vehicle 19, the operator releases the winch 16 lowering the dolly from the vehicle by IS allowing the drawbar 13, 14 to pivot relative to the vehicle 19. As the dolly is lowered the gas spring I S causes the drawbar to adopt the extended position. Once the dolly has been partly lowered, so that the wheel units are clear of the vehicle 19, but before the wheels S of the wheel units touch the ground the winch 16 is stopped. The operator then rotates the lead screw 7 by way of the drive nut 8 using an appropriate handle or motor. Owing to engagement of the lead screw 7 with the lead screw nuts 6 of the wheel units, the wheel units are driving in opposite directions away from the drawbar 13, 14 causing the telescopic axles connecting the wheel units to the draw bar to extend. When the wheel units have been extended to a sufficient extend the operator stops turning the lead screw 7 and again releases the winch 16 to fully lower the dolly from the recovery vehicle 19 ready to receive a vehicle to be towed. The entire operation can be conducted from one side of the recovery vehicle, avoiding the need for the operator to stand near passing traffic. The degree of extension of the wheel units may be varied as desired to accommodate a vehicle to be towed.

The above embodiment is described by way of example only. Many variations are possible without departing from the invention.

Claims

Claims 1. A vehicle recovery apparatus comprising a drawbar having an axis

and two wheel units mounted relative to the drawbar on opposite sides respectively of the axis of the drawbar wherein said wheel units are moveably mounted relative to the drawbar such that they may be moved to extended and retracted positions relative to the drawbar along an axis which is generally orthogonal to the axis of the drawbar.
2. The vehicle recovery apparatus of Claim l wherein the wheel units are mounted lO relative to the drawbar by means of an extendable member, or respective extendable members.
3. The vehicle recovery apparatus of Claim 2 wherein the or each extendable member is telescopic.
4. The vehicle recovery apparatus of Claim 2 wherein the or each extendable member comprises a main axle fixed to the drawbar and an outer axle moveable relative to the main axle.
5. The vehicle recovery apparatus of Claim 4 wherein each wheel unit may be mounted on an outer axle and is preferably moveably or slidably mounted on an outer axle.
6. The vehicle recovery apparatus of any of Claims 2 to 5 wherein a stop or stops are provided to limit the amount of extension of the extendible member.
7. The vehicle recovery apparatus of Claim 6 wherein the stop comprises a lug.
8. The vehicle recovery apparatus of Claim 6 wherein the stop comprises a spring loaded pin.
9. The vehicle recovery apparatus of any preceding Claim wherein said wheel units each comprise a wheel carrying platform and a rotatable wheel.
10. The vehicle recovery apparatus of any preceding Claim wherein there is provided a driving means for driving the wheel units between the retracted and extended positions.
11. The vehicle recovery apparatus of Claim 10 wherein said driving means comprises a lead screw.
12. The vehicle recovery apparatus of Claim 11 wherein said lead screw is attached to the drawbar.
13. The vehicle recovery apparatus of Claim 11 or 12 wherein said wheel units comprise lead screw nuts that are threadedly engaged with the lead screw.
14. The vehicle recovery apparatus of any of Claims 11 to 13 wherein the lead screw is threaded in opposite directions on either side of said drawbar respectively.
15. The vehicle recovery apparatus of any of Claims 11 to 14 wherein the lead screw is operable by means of a driving nut situated at the end of the lead screw.
16. The vehicle recovery apparatus of any preceding Claim wherein said drawbar comprises two portions pivotable relative to each other, one of said portions being attachable to and pivotable at a base.
17. The vehicle recovery apparatus of Claim 16 wherein said drawbar comprises means to urge the two portions of the drawbar relative to each other such that the drawbar is extended.
18. The vehicle recovery apparatus of Claim 17 wherein said means to urge the two portions of the drawbar relative to each other comprises a resilient means.
19. The vehicle recovery apparatus of Claim 18 wherein said resilient means is a gas spring.
20. The vehicle recovery apparatus of any preceding Claim wherein said vehicle recovery apparatus is mounted on a vehicle.
21. The vehicle recovery apparatus of any preceding Claim wherein the vehicle recovery apparatus is a tow dolly.
22. A vehicle recovery apparatus substantially as described herein with reference to the accompanying drawings.