GB2059896A - Improvements in or relating to vehicle recovery tow bars - Google Patents

Abstract

A tow bar comprising an assembly of telescopic sections 1, 2, 3 wherein the free ends of leading and trailing sections are adapted to be coupled respectively to a towing vehicle and a vehicle to be towed, the overlapping portions of adjacent sections of the extended tow bar being formed with holes for the reception of locking pins 9, 9a, 11, 11a which serve to retain the sections extended, and means for engaging said pins and holding them in operative positions against unintentional displacement. <IMAGE>

Description

SPECIFICATION Improvements in or relating to vehicle recovery tow bars This invention relates to a tow bar intended primarily for vehicle recovery services, i.e. for use in towing a broken down or damaged road vehicle to a garage but, as will hereinafter become apparent, may be used for analogous purposes, e.g. for launching and beaching boats on a seashore and also for towing light aircraft.

The primary object of the invention is the provision of a tow bar that is capable of being retracted from an extended position of use into a short compact and portable state so as to occupy the minimum of space when not used and so facilitate storage, handling and transport thereof.

According to the present invention a tow bar is provided that comprises an assembly of telescopic tubes that are adapted to be held rigidly in an extended position of use by removable locking pins inserted through registering holes in adjacent end portions of the tubes where they telescope one into another, said pins being held by readily releasable means against unintentional or accidental displacement from operative locking positions, said means when released permitting removal of the locking pins and retraction of the tubes into one another to form a comparatively short compact and portable state.

The enable the invention to be clearly understood and readily carried into effect a preferred embodiment thereof will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a purely diagrammatic longitudinal section showing the assembly of telescopic tubes collapsed to assume a compact out-of-use state.

Figure 2 is a similar view drawn to a smaller scale and showing the assembly of telescopic tubes fully extended and locked in a position of use.

Figure 3 is a view of the locking pins and an elastic retaining ring therefor and Figures 4, 5 and 6 are side, plan and end views respectively of a modified attachment for coupling the ends of the tow bar to towing and towed vehicles.

Referring to said drawings the tow bar comprises three telescopic tubular sections 1, 2 and 3, the outer leading end of the largest diameter section 1 being fitted with a swivelreceiving connection that can be attached to a clamp 1 b of a towing vehicle and the outer or rear or trailing end of the smallest diameter section 3 being fitted with a swivel-receiving connection that can be attached to a clamp 3b of a vehicle to be towed. These three tubes 1, 2 and 3 will hereinafter be referred to briefly as the leading, centre and trailing sections respectively as viewed when the towing vehicle travels in a forward towing direction.

The leading end of the loading section 1 is fitted internally with a fixed transverse bolt or pin 6 extending diametrically across the inside 'of the section 1 and to which is anchored one end of a stop rail 4 that extends longitudinally through this leading section 1 and passes through a hole in a cross member 7 at the leading end of the centre section 2 and at its other end, to the rear of the cross member 7, is provided with a stop 8 that abuts the rear face of the member 7 and limits movement of and complete withdrawal of the leading end of the centre section from the rear end of the leading section 1.

The centre section 2 is fitted internally with a stop rail 5 that extends longitudinally through this centre section and is fixedly secured at its leading end to a cross pin or member 10 in this centre section 2. This stop rail 5 is slidable through a transverse hole in a cross-member 1 2 extending transversely across the inside of the leading end of the trailing and smallest diameter section 3 and the rear or trailing end of this stop rail is provided with an abutment or stop 1 2a that cannot pass through the hole in the member 1 2 through which the stop rail 5 slides and so limits the extension of the trailing section 3 from the centre section 2 and so prevents complete withdrawal therefrom.

An elastic cord (not shown) is connected internally of and between the leading and centre sections 1 and 2 of the tow bar and serves, when the sections are extended into a position of use, to yieldingly resist and terminate extension of the centre section 2 from the leading section 1 and subsequent retraction of these two sections one into the other.

Conveniently this elastic cord is anchored at its ends to the pin 6 and the member 7.

The end portions of the tubular sections where they overlap or telescope, that is between adjacent ends of the leading and centre sections 1 and 2 and between the centre and trailing sections 2 and 3 are each formed with two transverse holes, spaced apart longitudinally of the sections, the two holes of one section, when aligning and made to register with two transverse holes of a mating section receiving removable locking pins 9 and 9a, and 11 and 11 a respectively that lock together mating ends of adjacent sections and so prevent separation of the sections when extended.

Preferably interengaging ends of the leading section and the centre section are formed with two pairs of transverse pin receiving-holes 9 and 9a, the holes of one pair 9 being disposed at 90 to the other pair 9a. In this manner the leading and centre sections 1 and 2 can be connected to the trailing section 3 in the required one of either two different posi tions spaced apart at 90" to suit connecting swivels at the leading end of the leading section 1 and on the trailing end of the trailing section 2 to suit different positions of towing hooks on vehicles.

The locking pins 9, 9a, 11 and 1 la each comprise (see Fig. 3) a shank portion 1 3 that can extend transversely through said holes in end portions of two adjacent tubes and a channel-iil < e head portion having side flanges 1 4 that are rounded so as to be complementary to the curvature of the outer of two adjacent tube ends so as not to project unduly from the face thereof.The locking pins 9, 9a, 11 and 1 a of the connected-together tubes are held in position by stout elastic securing rings 1 5 that encircle each outermost tube and pass through the channel 1 6 of the locking pin head and over the opposite free end 1 7 of the shanle 13 of the pin.

To facilitate registration of the holes for receiving the locking pins when the tubular sections are extended, adjacent ends of the tubes are distinctively marked with longitudinal bands that can be lined up to form a continuous band when adjacent sections are properly positioned, the bands being such as ta be visible in darkness to ensure correct positioning.

The leading end of the leading section 1 of the tow bar is fitted internally with a short tube constituting the swivel-receiving connection 'ia and that fits for part of its length within the leading end of this section and is secured therein by a cross bolt, the projecting end of this short tube being closed at its outer end by a rubber buffer 1 c and being provided with a swivel for coupling the tow bar to a towing vehicle.

The rear end of the trailing section of the tow bar is closed by a rubber buffer 3c and is also fitted with a suitable swivel for connec tionto a vehicle to be towed.

The arrangement is such that when the tow bar is required to be used the sections 1, 2 and 3 are extended from a retracted collapsed out-of-use position shown in Fig. 1, the elastic cord between the leading and centre sections 1 and 2 yieldingly resisting final extension of these two sections when the holes for the locking pins 9 and 9a are about to align whereupon these pins can be passed through the holes, complete and unintentional separation of the sections 1 and 2 being prevented by the stop 8 engaging the member 7 through which the rail 5 passes.When the trailing section 3 is full extended from the centre section 2 the abutment 1 2a on the stop rail 5 fitted inside the centre section engages said abutment member 1 2 and in this position locking pins 11 and 11 a are passed through the aligned holes in the overlapping portions of the centre and trailing sections 2 and 3. When the locking pins are in position to lock all sections rigidly together the elastic rings 1 5 are engaged in the heads 1 6 of the pins to hold these pins against unintentional movement.

When it is required to collapse and retract the sections into an out-of-use position the above procedure is reversed and the elastic securing rings 1 5 moved out of engagement with the locking pins (conveniently on to adjacent portions of the sections so as to be readily available for further use) and the pins removed and the sections telescoped together.

Although it is considered most practicable to construct the tow bar of three sections, it may be made of two sections or more than three, the general arrangement described above being employed but appropriately adjusted.

Figs. 4, 5 and 6 illustrate a modification for attachment to each end of the tow bar so as to limit the swivelling action and over-riding of the clamps.

According to this modification, each attachment comprises a small tubular portion 1 7 of oval cross-section that is bolted at 1 8 to a slightly flattened and correspondingly oval end portion of the leading end of the section 1 and the trailing end of the section 3.

Opposite upper and lower faces of the portion 1 7 are each formed with a U-shape cut-away 1 7a to expose aligned holes 1 8a in opposite sides of the associated end section 1 or 3 with which can be aligned holes in 1 9 and 19a of a shackle 20 intended to be engaged with complementary parts of the towing and towed vehicle, said shackle being connected to an end portion of a section 1 or 2 by a bolt 21 that can be passed through a plain hole in one of the bosses 19, then through the aligned holes in said end of the section 1 or 3 and a threaded end of the bolt then screwed through a threaded hole in the boss 1 9a, the bolt being provided with a hand-actuated lever 22 to permit this to be done.

The said portion 1 7 of the attachment adjacent to the mouths of the U-shape cut-aways 1 7a is formed with a pair of slightly curved side wings 23 braced by a bridging bolt 24 and between which pass the limbs of the shackle 20, these wings 23 limiting swivelling movement of the shackle and so preventing excess movement of the shackle and over riding and separation from the clamps. The curvature of the side wings 23 allows for a bali tow hitch. A free running safety towing rope may be fitted in clamps attached to both ends of the tow bar.

Claims (10)

1. A vehicle tow bar comprising an assem bly of telescopic tubes that are adapted to be held rigidly in an extended position of use by removable locking pins inserted through registering holes in adjacent end portions of the tubes where they telescope one into another, said pins being held by readily releasable means against unintentional or accidental displacement from operative locking positions, said means when released permitting removal of the locking pins and retraction of the tubes into one another to form a comparatively short compact and portable state.

2. A tow bar according to Claim 1, wherein certain of said tubes accommodate stop rails that limit withdrawal of a tube from an adjacent tube, each of said stop rails being fixedly secured at one end to a cross member in one tube and being slidable through an opening in an abutment member in an adjacent tube and being provided at its end at the other side of the abutment member with a stop that engages said abutment member and limits further withdrawal of said adjacent tube when the latter has been almost fully extended from the first mentioned tube.

3. A tow bar according to Claim 1 or 2, wherein outer free ends of the leading and trailing tubes are fitted with swivel devices by which the tow bar can be coupled to a towing vehicle and a towed vehicle respectively.

4. A tow bar according to Claim 1, 2 or 3, wherein each of said swivel devices incorporates an attachment for limiting the swivel action of the coupling and overriding of the coupling.

5. A tow bar according to any of the preceding claims, including an elastic member connected between and internally of an adjacent pair of tubes and that serves yieldingly to resist and terminate extension of the tubes pending alignment of the locking pin holes when the tubes later are being extended into a position of use.

6. A tow bar according to any of the preceding claims, wherein two pairs of locking pin holes are formed in interengaging ends of a pair of adjacent tubes, the holes of one pair being disposed at 90 to the other pair, to enable the coupling swivels to be set to suit the position of towing hooks.

7. A tow bar according to any of the preceding claims, wherein each of said locking pins comprises a shank and channel-like head portion in which an elastic pin-retaining ring encircling the tow bar can engage to hold the pin in position.

8. A tow bar according to any of the preceding claims, wherein to facilitate registration of the holes for receiving the locking pins when the tubular sections are extended, adjacent ends of the tubes are distinctively marked with longitudinal bands that can be lined up to form a continuous bank when adjacent sections are properly positioned.

9. A tow bar assembly according to any of the preceding claims, comprising an assembly of three telescopic tubes, the outer leading end of the largest diameter tube being adapted to be coupled to a towing vehicle and the trailing end of the rear end smallest diameter tube being adapted to be coupled to a vehicle to be towed.

10. A tow bar constructed substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.