GB2046700A - Yoke - Google Patents

Abstract

A lifting yoke, for example for a motor vehicle, has each end constructed as an open box comprising side plates (4, 5) with a vertical sleeve therein for receiving a stub shaft of a lifting fork 15. The upper edges of the side plates have teeth and grooves to co-operate with grooves and teeth on an upper horizontal plate secured to the sleeve and a further horizontal plate secured to the lower end of the sleeve limits lifting of the sleeve by abutting the lower edges of the side plates. The lifting forks (15) can thus be readily adjusted in position along the yoke by disengaging the teeth and grooves, moving the fork-receiving sleeves and then re-engaging the teeth and grooves. <IMAGE>

Description

SPECIFICATION Yoke The present invention relates to a yoke designed in each end to be provided with an upright lifting fork or other support for the object to be lifted, particularly a yoke for lifting motor-cars by applying the lifting forks under an axle of the car or under other suitable lifting point and thereafter pushing the yoke upwards.

Yokes for lifting motor-cars are well known in the art and are commonly used on breakdown lorries for front axle lifts. In order to make it possible to utilize one and same yoke for salvaging cars having different axle dimensions and axle designs it is necessary that the distance between the lifting forks can be adapted to the design of the car in the region of the axle. To that purpose yokes for lifting motor-cars hitherto used are provided with a plurality of fixed sleeves in each end portion of the yoke. By choosing a proper pair of sleeves it is therefore possible to a certain extent to adapt the distance between the furks to the circumstances.

It is an object of this invention to improve the possibilities of more accurately arriving at a desired distance between the forks. It is a second objective to adjust the distance between the forks without having to take out the forks from their respective sleeve, which would bring about a possibility to adjust the distance also when the yoke is placed under the car which shallbe lifted.

Another object is to offer a yoke which is easy to handle but which nevertheless satisfies high demands as to reliability. Further it is an object to offer a yoke provided to resist high strains in the region of the forks because of the heaviness of the car.

Further objects and advantages of the invention will be apparent from the following description of a preferred embodiment. Herein it will be referred to the accompanying drawings in which Fig. 1 is a side-view illustrating a yoke according to the preferred embodiment, as well as a pair of associated lifting forks shown by dashed lines.

Fig. 2 is a top-view showing the same yoke without lifting forks.

Fig. 3 is a section A-A in Fig. 2 at a larger scale.

Fig. 4 is a section B-B in Fig. 2 at the same scale, and Fig. 5 shows in the same scale the portion C encircled in Fig. 1, corresponding to a portion of a view C-C in Fig. 2 (the lifting fork not being shown).

Referring first to Fig. 1 and Fig. 2 a yoke is generally shown as 1. The yoke 1 according to the selected embodiment has a straight configuration including a central portion 2 and identically designed end portions 3. Along the entire length of the yoke there extend two vertical, parallel side plates 3 and 4. The central portion 2 consists of a welded box which is open in its ends, said box being defined by the two side plates 3 and 4 and an upper and a lower cover plate 6 and 7 respectively. The cover plates 6 and 7 serve to make the yoke rigid and to prevent it from being deformed in the region of the central portion 2.

Through the latter there extends a vertical shaft journal 8 provided to be connected to a lifting device which is not shown in the drawings. In order to make the construction more rigid there are further profile bars 9 and 10 welded to each side plate 4 and 5 respectively.

Each end portion 3 has the form of an elongated box 11 without cover or bottom. The boxes 11 terminate in their outer ends by an end plate 12. In each of the open boxes 11 there is provided a sleeve 13, Fig. 4, the outer diameter of which is slightly smaller than the distance between the side plates 4 and 5. The sleeve 1 3 therefore can be displaced in the box 11 between the end plate 12 and the edge of the cover plates 6 6 and 7 of the central portion 2. The inner diameter of the sleeve 13 is selected such that a shaft journal 14 of a lifting fork 1 5 can be journaled in the sleeve.

The possibilities of displacing the sleeve 1 3 in the vertical direction is restricted by the fact that the sleeve 13 in its upper end is connected to a rectangular plate 1 6 with a through-boring for the sleeve 13, and by the fact that the sleeve in its lower end is connected to an equally large rectangular plate 17. The plates 1 6 and 17 extend past the outer surfaces of the side plates 4 and 5.

The sleeve 13 in other words is locked in the open box 11 by means of the plates 16 and 17. The lower plate 1 7 is provided with a central opening 1 8 serving as a drainage hole. In order to prevent the side plates 4 and 5 from being buckled or in any other way deformed due to the heaviness which e.g. a motor-car may exert upon the side plates 4 and 5 via the lifting forks 15 the upper and lower plates 1 6 and 1 7 on outside of the side plates 4 and 5 are provided with catch plates 19 and 20, respectively.The catch plates 1 9 and 20, which extend downwards from the upper plate 16, and upwards from the lower plate 17, respectively, thus serve to prevent the side plates 4 and 5 from being out-buckled under the exertion of a heavy load.

Referring now also to Fig. 5 the upper edges 21 and 22 of the side plates 4 and 5, respectively, are provided with grooves in the region of the end portions 3. More particularly the upper edges 21 and 22 have been made saw toothed. According to the selected embodiment the teeth, which are designated 23, have been given right angles, Fig.

5. The tooth height has been designated d1. The under side of the plate 1 6 has been provided with teeth 24 having the same shape and size as the teeth 23 so that the plate 1 6 by being lowered towards the side plates 4 and 5 may be secured in the adopted position.

The distance d2 between the lower edge Df the side plates 4 and 5 and the lower plate 17 is slightly, which means about 2-5 mm, larger than the tooth height d,. By pushing the plate 1 7 to a maximal fit-up against the lower edge of he side plates 4 and 5 it is thus possible to release the teeth 24 of the plate 1 6 from their contact with the teeth 23 of the side plates 4 and 5.

Thereafter -- but not before - the sleeve 13 may be displaced in the box 11 from one position to another. This effectively prevents the sleeves 1 3 and the lifting forks 1 5 provided in the sleeves from involuntarily changing their position.

Claims (8)

1. A lifting yoke having each end constructed as an open box formed of two longitudinally extending parallel side plates and at least one transverse end plate; wherein a respective sleeve fcr receiving a shaft of a lifting member extends through each said open box, said sleeve having an outer diameter which is smaller than the distance between the said parallel side plate so that each sleeve may be displaced in the box longitudinally of the yoke between two end positions, said sleeve being securable in several different alternative positions between the end positions.

2. A lifting yoke according to claim 1, wherein at each end of the yoke a respective first plate is secured to the sleeve and has a through-hole for the sleeve and/or for the said shaft bar to be received by said sleeve, and a second plate parallel to said first plate is secured to the sleeve such that said first and second plates limit the movement of said sleeve along its own longitudinal axis by abutting said side plates.

3. A lifting yoke according to claim 2, wherein at least one of said first and second plates extends laterally of said yoke beyond the outer surfaces of said side plates which define said box, and that from said at least one plate there extends a pair of flanges overlapping said side plates to resist outward buckling of said side plates because of the load upon the yoke.

4. A lifting yoke according to claim 3, wherein both said first and second plates are provided with said flanges overlapping the side plates.

5. A lifting yoke according to any one of claims 1 to 4, wherein along an open side of each said box the edges of the side plates are provided with teeth and grooves and the associated first plate lies adjacent said toothed edge and has on its face which lies adjacent said teeth and grooves corresponding teeth and grooves to co-operate therewith to hold said associated first plate against movement longitudinally of said box, and wherein the distance between the edges of the side plates opposite their toothed edges and the associated said second plate is larger than the depth of the grooves, whereby it is possible to release each first plate from its engagement with the toothed edges of the side plates by moving the said sleeve axially to shift it laterally of the box so that the said second plate is pressed against the said opposite edges of the side plates whereupon the sleeve may be displaced along the yoke to any desired position in the box and secured in that position by thereafter being moved axially to brings its teeth and grooves into engagement with the grooves and teeth of the side plates.

6. A lifting yoke constructed and adapted to operate substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

7. A method of lifting a motor vehicle comprising taking a lifting yoke according to claim 5 with lifting forks engaged in the said sleeves by fitting of a shaft of each said lifting fork in an associated one of said sleeves, attaching each said lifting fork under a respective side of the vehicle at one end thereof, and lifting the centre of said yoke to lift the said one end of the vehicle, wherein the yoke has said teeth and grooves of the side plates at the upper edges of said side plates with the side plates vertical and the shaft of each lifting fork is engaged in the upper end of its sleeve, and the position of the lifting forks along the yoke is adjusted by lifting the sleeve to disengage the teeth and grooves of the associated said first plate from the grooves and teeth of the side plates and then moving the sleeve with its first and second plates longitudinally of the yoke to the desired new position before relowering the said first plate and sleeve to re-engage the teeth and grooves.

8. A method of lifting a vehicle substantially as hereinbefore described with reference to the accompanying drawings.