GB2239232A - Recovery vehicles - Google Patents

Abstract

A recovery vehicle mechanism comprises an arm pivotably mounted on the rear 12 of a recovery vehicle 10 and a spectacle frame 15 carried on the arm, wherein the arm comprises an assembly of an inner arm 17 and an outer arm 16, the inner arm being pivoted at 20 at its front end on the recovery vehicle, and the outer arm being pivoted at 26 at its front end on the back end of the inner arm. The outer arm includes an extension 30 on which the spectacle frame is carried. The inner and outer arms and the extension are controlled by respective hydraulic rams 22, 27, and 31. The ram 22 controlling the inner arm is mounted between a point 23 on the vehicle close to the front end of the inner arm and a point 24 on the inner arm near its back end; the ram 27 controlling the outer arm is mounted between the pivot point 20 of the inner arm and a point 28 on the outer arm near and below its pivot point with the inner arm; and the outer arm is of box section with the ram 31 controlling the extension mounted inside it. <IMAGE>

Description

Reco very Veh c les The present invention relates to recovery vehicles; that is, to vehicles which are used to transport cars (and other vehicles) which have broken down, generally on the road.

Such recovery vehicles are well known. I In the early designs, the vehicle consisted cf 3 pick-up truck or other flat-bed truck, with a small crane mountej at the back. Te wire or chain of the crane would be attached to a suitable point underneath the broken-down car, e.g. near the front, and the crane would then lift the front end of the car so that it could be towed.This arrangement has the disadvantage that the wire or chain is liable to damage the front of the broken-dowr-, vehicle, since a firm fixing point is usually found only some little way hack from its fr-ont and the lifting wire then has to pass under and round the front bumper, the bottom edge of the front grille, etc.

A modified design of recovery vehic-le has therefore become popular, in which an arm extends backwards from the recovery vehicle and i, constructed to bring its outer end down to near ground level, and carries at its outer end transverse bar with two rectangular frames attached to it, forming a "spectacle frame", onto which the front wheels of the broken-down vehicle can be placed.

The arm is pivoted at its forward end on a pivot attached to the chassis of the recovery vehicle, and a hydraulic ram is attached between the chassis and the arm so that the arm can be lifted when the broken-down vehicle is on the spectacle frame.

The spectacle frame may be carried on an extension slideable within the arm and controlled by a further hydraulic ram, to allow the distance between the front of the broken-down vehicle and the back of the recovery vehicle to be adjusted. The spectacle frame may also be pivoted on the arm (or extension) with a vertical pivot axis, to allow the broken-down vehicle to follow the recovery vehicle more easily. It may also t,e pivoted on the end of the arm so that it can be raised to a vertical stowage position when there is no broken-down vehicle bering towed.The arm is mounted on a pivot whic h is located on the body of the recovery vehicle generally in the vicinity of the back axle, and the main portion of the arm is generally roughly horizontal.

While this arrangement has hitherto been generally satisfactory, we have realized that it represents a compromise between two requirements, one of which is becoming more stringent and will therefore make the compromise less satisfactory.

More specifically, one of the requirements is that the lower-most point of the forward end of the arm must provide adequate ground cleai'ance, and should therefore be e eood distance above ground level.The other requirement is that it must be possible to introduce the spectacle frame, or, the end of the arm, underneath the broken-down vehicle without damaging that vehicle. It must also be possible to raise the spectacle frame and arm without damaging the broken-down vehicle.) One trend in modern car design is towards lower rc'-und clearances, and more specifically towards provijine skirts at the front of the car which pr iduce a relatively low ground clearance at the front.The space available for introducing the spectacle frame beneath th; car as far as the front wheels is there fore restricted. Further, the car may be on an uneven r oad when it breaks down, so that the recovery vehicle may be at a -=lishtly different level and/or angle to the broken-down vehicle. This makes suitable design of the arm geometry even more difficult.

According to the present invention, there is provided a recovery vehic-le mechanism comprising an arm pivotably mounted on the rear of a recovery vehicle and a spectacle frame carried on the arm, wherein the arm comprises an assembly of an inner arm and an outer arm, the inner arm being pivoted at its front end on the recovery vehicle, and the outer arm being pivoted at its front end on the back end of the inner arm.

Preferably the outer arm includes an extension on which the spectacle frame is carried. Preferably also the inner and outer arrans and the extension are controlled by respective hydraulic rams. The ram controlling the inner erm may be mounted between a point on the vehicle close to the front end of the inner arm and a point on the inner arm near its back end: the ram controlling the outer arm may be mounted between the pivot point of the inner arm end a point on the outer arm near- and below its pivot point with the inner arm; and the outer arm may be of box section with the ram controllinS the extension mounted inside it.

Further features of the invention, and modifications thereof, will nowl be described with reference to the drawings, which show, buy way of example, a recovery vehicle embodying the invention, and in which: Fig. 1 is a side view of the rear part of the vehicle, partly in section, and Fig. 2 is a partial top view of the rear part of the vehicle.

F,eferring to Fig. 1, a recovery vehicle 10 has 3 cab 11 only partly shown) and a rear body portion 12 with one tack wheel 19 visible. A spectacle frame 15 is mounted on the vehicle via an arm structure comprising an outer arm 16 and an inner arm 17, the outer arm 16 being mounted on the inner arm 17 and the inner arm 1? being mounted on the body 12 of the vehicle.

More specifically, the inner arm 17 is pivoted 3t a Pivot 20 mounted on a bracket 21 forming part of the body 1 at the location shown. (It will be understood that while the relative size-. and locations of the v-Jrious components are shown in approximately correct relationships qualitatively, no attempt has been made to show precise dimensions.) A hydraulic ram 25 i mounted between pivot 23 on the bracket 21 and 9 pivot 24 on the inner arm 17, and can therefore be used to raise and lower the back end of that arm.

The outer arm 16 is enlarged at 25 at its front end, and is pivoted st this enlargement on a pivot 26 carried on the outer end of the the inner arm 17. A hydraulic ram 27 is mounted between the pivot 20 on the bracket 21 end pivot 28 on the front end of the inner arm 17, and can therefore be used to rotate the outer arm 16 ebout the back end of the inner- arm 17.

The outer arm 16 is of box section, and has an extension 30 slidable with it. A hydraulic ram 31 is mounted in the outer arm 16 between the pivot 28 and a pivot 32 on the extension 30, and can therefore be used to move the extension 30 in and out of the outer arm 16. The back end of the extension 30 has a bracket 35 pivoted on it by a pivot 36.

The spectacle frame 15 consists ot two frames 37 fixed to a shaft 38 which is in turn pivotally mounted on the bracket 35, which includes stop means 3(3 so that the spectacle frame 15 can notate upwards from the position shown but is held against any rotation downwards from that position.

Fig. 2 shows the appearance of the rear- of the arm mechanism and spectacle frame from above. The mechanism is mounted on the centre line of the vehicle, and the rear body portion 12 has a recess 40 formed in it to provide clearance for the back end of the inner arm 17. and ior the outer arm 16 when that is raised to the vertical position for stowage.

It will be realized that, by operating rar: 22, the pivot point of the outer arm 16 can be raised and lower-ed to any desired position. The outer arm can then be raised and lowered about that pivot point by the ram 27. Thus the spectacle frame 15 can be set to any desired height and angle for introduction beneath a broken-down vehicle.In addition, the extencion allows the spectacle frame 15 to be moved beneath the broken-down vehicle by the ram 21. It is also possible. to raise or lower the outer arm 16 bodily, with little or no rotation, by operating the two rams 22 and 27 together. l Alternative mechanisms, such as screw mechanisrns andsor winch and cable mechanisms, can be used to control the arms and extension. However, the use of hydraulic rams allows positive control of ea- h movement in both directions. It will also be realized that the underlying principle is that the pivot point of the outer arm should be movable vertically, and mechanical means other than a pivoted inner arm for achieving this may be employed.

Claims (7)

Clams

1 A recovery vehicle mechanism comprising an arm pivotably mounted on the rear of a recovery vehicle and a spectacle frame carried on the arm, wherein the arm comprises an essembly of an inner arm and an outer erm, the inner arm being pivoted et its front end on the recovery vehicle, and the outer arm being pivoted at its front end on the back end of the inner erm.

2 A recovery vehicle mechanism according to claim 1 wherein the outer arm includes en extension on which the spectacle frame is carried.

3 A recovery vehicle mechanism according to either previou claim wherein the inner and outer arms and the extension (if present) are controlled by respective hydraulic rams.

4 A recovery. vehicle mechanism according to claim 3 wherein the ram- control ling the inner arm is mounted between e point on the vehicle close to the front end of the inner arm and a point on the inner arm near it? back end.

5 A recovery vehicle mechanism according to either of claims 3 and 4 wherein the ram controlling the outer arm is mounted between the pivot point of the inner arm end a point on the outer arm near- and below its pivot point with the inner arm.

6 A recovery vehicle mechanism according to claim 2 or any claim directly or indirectly dependent thereon wherein the outer arm is of box section with the ram controlling the extension mounted insicle it.

7 A recovery vehicle mechanism substantially as herein described and illus trated.