GB2225975A - Device for facilitating the fitting and removal of large compression springs on motor vehicle axles - Google Patents

Abstract

A device for use in the fitting and removal of large springs 1 (Fig. 3) on motor vehicle axes has a tube 3 screw-threaded onto a spindle 2 connected with an articulated joint 17 to a threaded stud 15. The tube 3 rotatably supports a tray receiver 31 for engagement with a spring plate on the vehicle and having a hand grip 32. An intermediate disc 21 with projections 24, 25 is non-rotationally but axially displaceably-mounted on the stud between a clamping nut 20 and an axle- engaging abutment 19. The disc 21 is mounted on the stud 15 with a tongue and groove engagement 26, 28 and the projections 24, 25 cooperate with corresponding recesses 47 of a disc 46 (Fig. 3) secured to the vehicle axle to prevent rotation of the stud relative to the axle on tightening of the clamping nut. The upper end of the stud passes through a hole in the axle and is clamped non-rotationally on cooperation of projections and recesses of discs 21 and 46 on tightening of nut 20. The tube 3 may then be screwed up on spindle 2 to force the receiver 31 against the spring plate or cup 36 at the lower end of the spring to permit unbolting of said spring plate. <IMAGE>

Description

DEVICE FOR FACILITATING THE FITTING AND REMOVAL OF LARGE COMPRESSION SPRINGS ON MOTOR VEHICLE AXLES.

The invention relates to a device for facilitating the fitting and removal of large compression springs on motor vehicle axles.

A known device of this kind (DE-GM 78 00 663) consists of a threaded spindle with a screwed-on threaded tube which is provided with a tray receiver and with a key head, and a threaded stud which is connected to the threaded spindle by an articulated link. The threaded spindle is connected at one end by an articulated link to a coupling member tiltable to one side only, on the free end of which a relatively short threaded stud is disposed. The coupling member is provided with a support flange which serves as an axial rest for a spring receiving plate, while a T-piece can be screwed onto the threaded stud.

The T-piece possesses a diagonal tube open on both sides fixable on the threaded stud by means of lock nuts. In conjunction with the T-piece and a rod inserted through the diagonal tube of the latter it is possible to secure against rotation the threaded stud and hence the entire device during the fitting and removal of a motor vehicle axle spring if the rod and the diagonal tube are so adjusted that the rod rests against a stop face of the vehicle and if for example during the tensioning of the compression spring to be fitted or removed a torque is applied in a clockwise direction to the threaded spindle and hence also to the coupling member.

Two tray-shaped pressure plates with central holes are provided for receiving the springs to be fitted or removed, one of which is supported concentrically on the support flange of the coupling member and the other on the tray receiver of the threaded tube. Since the threaded spindle and the coupling member are connected to each other by an articulated link, this known device is also suitable for the fitting and removal of motor vehicle axle springs which exhibit a curved or buckled axis when fitted, i.e. with which the stop faces against which the two spring ends impinge are not exactly parallel to each other.Nevertheless, although it is also possible to use the T-piece screwed onto the threaded stud as an outer support instead of the second pressure plate by fixing the T-piece to a seat on the actual vehicle body, e.g. by means of a poked-through rod, the known spring tensioning member can be used only for the fitting and removal of motor vehicle axle springs the ends of which lie, when fitted, between two supporting surfaces the distance between which is less than the distance between the two pieces on which the supporting surfaces are disposed:: An object of the invention is to create a device with which it is also possible to fit and remove safely and reliably axle springs exhibiting a curved or buckled axis when fitted and bearing with at least one spring end against a supporting surface, e.g. of a spring receiving plate, which lies between, but outside, the two vehicle axle parts on which the axle spring is supported with which therefore at least one spring end of one of the two vehicle axle parts on which the axle spring is supported projects through.

This task is achieved according to the invention by the fact that the threaded stud comprises a tensioning member disposed torsionally-rigid but axially displaceable between an axial step bearing and a screwed-on tightening nut, said tensioning member being provided with a least one anti-rotation safety device e.g. in the form of a projection or depression, and being able to be fixed torsionally-rigid to the axle shaft of a motor vehicle by means of this anti-rotation safety device.

It is thus possible by means of the threaded stud to fix the entire tensioning member torsionally-rigid e.g.

to the axle shaft of a motor vehicle in such a way that the axis of the articulated link connecting the threaded stud to the threaded spindle runs diagonally to the plane in which the curved or buckled axis of the fitted axle spring lies. This-confers the substantial advantage that the axle springs can by means of this spring tensioner or this device for fitting and removal not only be tensioned and also relaxed in a simple and reliable manner, but that they can also be brought in a controlled manner and with secure hand-holds out of their buckled, tensioned position into their straight, relaxed position and vice versa.

Further developments of the invention which facilitate the handling and improve the safety of the handling may be appreciated from the following description.

An exemplifying embodiment of the invention will be explained in greater detail below with reference to the drawings, wherein: Fig. 1 is a partly cut-away side-view of a device constructed in accordance with the invention: Fig. 2. shows the articulated link according to a section II-II on Fig. 1; Fig. 3. is a simplified representation of a double wishbone wheel suspension of a motor car with a compression spring and a device of the kind according to the invention which is fixed to the axle shaft for the removal of the compression spring; and Fig. 4. is a partly cut-away side-view of a tensioner.

The device represented in the drawings serves for the fitting and removal of a large compression springs 1 on motor vehicle axles, in particular on double wishbone wheel suspensions. The device consists of a threaded spindle 2 onto which, starting from its free end, is screwed a threaded tube 3 the internal thread 4 of which extends only over an upper end section a which has a length of approximately 1.5 to 2 cm. The threaded tube 3 is provided at its lower end with a circular flange 6 and a hexagonal key head 7.

The upper end of the threaded spindle 2 is provided with a bearing yoke 8 comprising two bearing eyes 9 and 10 with coaxial holes 11 and 12 in which a journal pin 13 fits snugly. A complementary bearing eye 14 of a threaded stud 1 is supported rotatably on the journal pin 13. The length of this threaded stud 15 is substantially less than the length of the threaded spindle 2. The stud 15 has an external thread 16 which extends into the vicinity of the bearing eye 14 and which forms jointly with the two bearing eyes 9 and 10 and the journal pin 13 of the threaded spindle 2 an articulated link 17 by means of which the bearing stud 15 opposite the threaded spindle 2 can be pivoted about the articulated link axis 18 which is simultaneously the axis of the bearing stud 13.

In the vicinity of the bearing eye 14 the threaded stud 15 is provided with a screwed-on and hence axially adjustable axial step bearing 19 in the form of a circular disc provided with an internal thread. A tightening nut 20 is screwed onto the threaded stud 15 starting from the upper end. Between the tightening nut 20 and the axial step bearing 19 is disposed an axially displaceable tensioning member 21 in the form of a circular disc 22 comprising on the front side 23 facing the axial step bearing 19 two diametrically opposite axial cams 24, 25 which are trapezoidal-shaped in side elevation. These axial cams 24 and 25 serve as an antirotation safety device in the manner described in greater detail below. The tensioning member 21 or the circular disc 22 is connected torsionally-rigid to the threaded stud 15 by a tongue and groove joint 26. This joint 26 consists of an axial groove 27 in the threaded stud 15 and a grooved tongue 28 which is fixed in the hole 29 of the circular disc 22 and runs in the axial groove 27.

A tray receiver 31 which is provided with a grip piece 32 fixed eccentrically thereto is supported by means of an axial thrust bearing 30 on the circular flange 6 of the threaded tube 3. The tray receiver 31 takes the form of a guide boss 33, in which the axial thrust bearing 30 is accommodated, and a circular disc 34 with a conical edge which can be manufactured from a single piece or be composed of two pieces. On its front face facing the articulated link 17 the circular disc 34 has several depressions 35 which ,in co-operation with a spring receiving plate 36 (represented in Fig. 3) forming part of the vehicle and possessing corresponding counterparts, act as engaging means by means of which a torsionallyrigid connection can be made between the tray receiver 31 and the spring receiving plate 36.The grip piece 32 is in the form of a pin 40 which runs radially and diagonally to the common axis 5 of the threaded spindle 2 and the tray receiver 31 and is fixed rigidly in a receiving member 37 fixed onto the underside of the circular disc and to the guide boss 33.

The application of the spring tensioner whose composition is described above and of the device for the fitting and removal of large compression springs on motor vehicle axles described above is as follows: Assume that the compression spring 1 which bears with its upper end against the underside 38 of an axle shaft 39 and the lower end of which is positioned centrally in the already mentioned spring receiving plate 36 is to be removed. It should be borne in mind for this that the spring receiving plate 36 is bolted by several screw bolts 41 to the underside of a two-shank wishbone 42 and that the compression spring 1 has, when fitted, a curved axis 43, which results in the underside 38 against which the upper spring end impinges not being parallel with the supporting face of the spring receiving plate 36 on which the lower spring end is supported.It must also be assumed that the axle shaft 39 possesses a diagonally disposed hole 44 and is provided on its upper side 45 with an anti-rotation safety device 46. This device 46 is disposed concentrically to the hole 44 and comprises two diametrically opposite trapezoid-type recesses 47 and has the shape of a circular disc with the same diameter as the circular disc 22.

It can be seen from Fig. 3 that the two front-side recesses 47 are designed for the positive seating of the two axial cams 24 and 25 and are also of corresponding cross-sectional form.

First of all the threaded stud 15 is poked from below through the hole 44 in the axle shaft 39 until the axial step bearing 19 impinges against the underside 38, after which the tensioning member 21 is placed on the threaded spindle 15 and brought by means of its cams 24 and 25 into torsionally-rigid engagement with the anti-rotation safety device 46 and braced snugly in this position against the axle shaft 39 by the tightening nut 20.

During these previously described operations the threaded tube 3 on the threaded spindle 2 is screwed onto the other end in such a way that the tray receiver 31 does not yet come into contact with the spring receiving plate 36. The tongue and groove joint 26 between the tensioning member 21 and the threaded stud 15 on the one hand and the arrangement of the axial cams 24, 25 and the recesses 47 on the upper front side of the anti-rotation safety device 46 on the other are so designed that in the position represented in Fig. 3, where there is engagement between the tensioning member 21 and the anti-rotation safety device 46 fixed rigidly and in a diagonal position coaxial with the drill hole 44 to the axle shaft 39, the pivoting axis 18 of the articulated link 17 runs diagonally to the plane in which the curvature of the axis 43 of the compression spring 1 lies.

After the fixing of the threaded stud 15 to the axle shaft 39 the tray receiver 31 is first of all moved from below against the spring receiving plate 36 by corresponding turning of the threaded tube 3, and in so doing the engagement means at the lower front side of the spring receiving plate 36 simultaneously engage with the depressions 35 in the tray receiver 31. If the tray receiver 31 now impinges with a certain initial stress against the underside of the spring receiving plate 36, the screw bolts 41 can be slackened and removed. When the screw bolts 41 have been removed, a relaxation of the compression spring 1 is effected by corresponding turning of the threaded tube 3 on the fixed threaded spindle 3.

As the spring receiving plate 36 moves downwards away from the underside of the wishbone 42, the compression spring 1 is able to align itself into a straight line.

Thus the spring receiving plate 36 aligns with the received lower spring end as it moves to the left. This alignment movement can be easily controlled by corresponding manual operation of the grip piece 32, so that no abrupt alignment movements can occur.

As soon as the compression spring 1 has assumed its straight position, the threaded tube 3 can be turned downwards until the spring is fully relaxed and then to its full extent by the threaded spindle 2. The spring can then be withdrawn downwards through the wishbone.

When the damaged spring 1 has been removed, the threaded stud 15 remains fixed to the axle shaft 39 until a new spring has been fitted. This fitting of the new spring takes place by the spring first of all being poked from below through the wishbone 42 and being brought to rest against the underside 38 of the axle shaft 39. At the same time or thereafter the threaded tube 3 with the tray receiver 31 and the superimposed spring receiving plate 36 is screwed from below onto the threaded spindle 2 and at the same time the lower spring end is centred in the spring receiving plate 36. When this has taken place, the tray receiver 31 must be held firm against rotation by means of the grip piece 32 during further rotation of the threaded tube 3 in the tensioning direction. At the end of the tightening process it is then necessary by corresponding operation of the grip piece 32, which in order to prolong the lever arm can be provided with an extension, to bring the originally straight direction of the spring again into the position shown in Fig. 3 by corresponding displacement of the spring receiving plate 36 to the right. If then the screw holes of the spring receiving plate 36 are in line with the corresponding screw holes of the wishbone 42, the screw bolts 41 can be inserted again. The spring receiving plate 36 can then be screwed tight to the underside of the wishbone 42. The threaded stud 15 can then be slackened again from the axle shaft 39 after unscrewing of the tightening nut 20.

Claims (8)

1. Device for facilitating the fitting and removal of large compression springs on motor vehicle axles, said device comprising a threaded spindle engaging with a screw threaded tube which is provided with a tray receiver and with a key head, and a threaded stud which is connected to the threaded spindle by an articulated joint wherein: the threaded stud is associated with a tensioning member disposed torsionally-rigid but axially displaceable between an axial step bearing and a screwed-on tightening nut, said tensioning member being provided with at least one anti-rotation safety device, and being fixable torsionally-rigid to the axle shaft of a motor vehicle by means of this anti-rotation safety device.

2. Device according to claim 1, wherein the tensioning member is a circular disc possessing on its front side facing the axial step bearing two axial cams which are disposed in a diametrically opposite position to each other and in the plane formed by the articulated link axis and the axis of the threaded stud.

3. Device according to claim 1 or 2, wherein the tensioning member is connected torsionally-resistant to the threaded stud by a tongue and groove joint.

4. Device according to any one of claims 1 to 3, wherein the axial step bearing is a threaded disc screwed onto the threaded stud.

5. Device according to any one of claims 1 to 4, wherein the tray receiver is supported rotatably by means of an axial thrust bearing on a circular flange of the threaded tube and is provided with an eccentric grip piece.

6. Device according to claim 5, wherein the grip piece is a radial pin which is disposed at the periphery of a boss of the tray receiver diagonally to the axis of the latter.

7. Device according to claim 5 or 6, wherein the stop face of the tray receiver which faces the articulated link is provided with one or more eccentrically disposed engagement means in the form of depressions or elevations which can be brought into torsionally-firm connection with corresponding engagement means of a spring receiving plate.

8. A device substantially as described, with reference to, and as illustrated in the accompanying drawings.