GB2357267A

GB2357267A - Steering and suspension link connections

Info

Publication number: GB2357267A
Application number: GB0013361A
Authority: GB
Inventors: Stephen Maurice Rose; Andrew Raymond Bird
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-06-01
Filing date: 2000-06-01
Publication date: 2001-06-20
Anticipated expiration: 2020-06-01
Also published as: GB2357267B; GB0013361D0

Abstract

A pivotable link (21) and bent arm (25) are screw-threaded telescopically for transmission of end loads. The link and arm each have a recess (26). The recesses can be aligned and retained in alignment by a projection (28). The invention has particular application to steering joints of vehicles having a bent track rod or drag link.

Description

2357267 IMPROVEMENTS IN STEERING AND SUSPENSION LINKS This invention

relates to an improvement in pivotable links, and particularly to means for connecting an articulation, such as a ball joint, to an arm at a predetermined orientation and displacement.

Means for connecting pivotable links to arms are well known. Particularly in the field of steering and suspension joints, a ball joint body may be connected to an arm by means of a threaded shank; the thread may be external or internal. The end of the arm has a corresponding thread, and this form of connection permits the displacement of the ball centreline, and the orientation of the joint to be varied by relative or in out screwing. Such a connection method is used in vehicles for e.g. track rods and drag links of vehicle steering systems. The method is also used as a means of adjusting suspension camber, castor and the like in racing cars and on some road vehicles.

A particular difficulty arises in the case of bent arms, for example a bent drag link.

Arms should of course be straight where possible, but occasionally other suspension or chassis components require the use of a bent arm, in order to give adequate clearance for full steering movement. In these circumstances it is essential that the bent arm being installed has the correct orientation in order to ensure that the bend is away from the obstruction rather than towards the obstruction.

Accordingly the ball joint is usually permanently fixed against movement with respect to the arm at one end thereof, this ensures correct positioning of the arm with respect to the obstruction. However when the ball joint requires replacement it is necessary to purchase a joint and arm assembly which is rather more expensive than if the joint alone could be replaced. Furthermore, the entire arm must be removed from transfer of the usual joint at the other end; this is unnecessarily time consuming, and may require fine adjustment using specialist equipment, to set the precise effective length of the arm after re-installation.

2 What is required is a replaceable link for a bent arm, which has means to control both orientation and displacement in a manner which avoids incorrect assembly.

According to the invention there is provided a pivotable link and bent arm adapted for telescopic attachment, the link and arm each having a recess adapted to be aligned in a predetermined orientation and having securing means attachable to one of the link and arm, the securing means having a projection engageable closely in said recesses to retain the joint and arm at a predetermined insertion displacement and orientation.

In a preferred embodiment the recess comprises a through hole in the outer telescopic part and a blind hole in the inner telescopic part, it being understood that the through hole should extend through one side of the outer telescopic part but not through both sides. Preferably these holes are round and of equal diameter. The projection may comprise an inwardly directed pin of a saddle clamp adapted to be secured around the joint and arm.

In a preferred embodiment the telescopic parts are screwed threaded together.

Other features of the invention will be apparent from the following description of a preferred embodiment illustrated by way of example only in the accompanying drawings, in which:

Fig. 1 is a side elevation of a bent drag link.

Fig.2 is a transverse section through Fig. 1 in the direction of arrow B. Fig.3 is a partial axial section of a joint according to the invention; and Fig.4 is a transverse section through Fig.3 in the direction of arrow A.

Figs. 1 and 2 illustrate a prior art drag link comprising a tubular arm 11 having ball joints 12, 13 at the ends thereof. The arm 11 has a double bend, as illustrated, which is representative of a typical bent drag link.

The right hand joint 12 (as viewed) has a conventional male body 14 screw threaded into the arm 11 and secured at a desired displacement and orientation by a T' clamp 3 and a single pinch bolt 15. The tubular arm I I has a slot 19 at one side to permit the C' clamp to close the arm tightly onto the screw threads of the joint 12. This joint is adjustable -to permit the overall length of the drag link (between ball joints) to be varied, for example to position the vehicle steering wheel in a desired orientation.

The left end joint 13 is fixed in relation to the arm I I by upper and lower recesses 16 and axially extending protrusions 17. The arm is typically hot crimped into and around the recesses 16 and protrusions 17, and it will be apparent that the body 18 of the joint 13 is fixed immovably to maintain a desired distance C from the bend, and a desired orientation D with respect to the bend.

As will also be apparent, the joint 13 cannot be replaced as a unit since it cannot be removed from the arm 11.

Figs. 3 and 4 illustrate one embodiment of the present invention. A ball joint 21 has a threaded stem 22 extending from the body 23. This stem 22 is a screwed fit in a threaded bore of the arm 25, and in this respect is conventional. The threaded joint provides the necessary capability to exert axial loads through the joint connection.

The stem has a radial bore 26 at a predetermined axial distance from the ball and at a desired angle with respect to a median axis of the ball joint. As illustrated the bore extends in the same direction as the ball joint but any relative angular orientation is possible.

A saddle clamp 27 has a pin 28 projecting to the interior side and extending through a close fitting hole in the arm 25 and into the bore 26. The clamp is secured by nuts and bolts 29. The pin 28 may be attached in any suitable manner, for example by welding, adhesive or peening.

The pin 28 securely retains the stem 22 in the arm 25 at a desired displacement and angular orientation when the stem 22 is screwed in sufficiently, yet the joint 21 can easily be removed and replaced on removal of the saddle clamp 27. The pin ensures 4 location and correct orientation of the joint, but end loads are transmitted conventionally through the threads. A separate locking device, such as a lock nut or clamp (Fig. 1, 15) is not necessary, but the saddle clamp 27 can serve this purpose if the arm 25 has an end slot 30, as illustrated in Fig.4. Other arrangements are possible.

Apart from permitting replacement of the joint 21, and avoiding consequent dismantling of the other end of the arm 25, the invention has the important advantages that:

1. The stem 22 comprises a conventional threaded shank with a single radial hole 26. It is thus likely to be less expensive than the form locking shape required for the prior art joint 13, and is moreover a simple adaptation of a pre-existing and conventional joint.

2. The arm 25 requires a single radial hole, and is also likely to be less expensive than the hot pressing operation required for the priorjoint.

3. The saddle clamp 27 is a very inexpensive component.

4. The general configuration of the replaceable joint will be well understood by a mechanic without requiring reference to manuals and the like.

5. More or less pins 28 can be provided as required, each having a unique position so as to avoid assembly of the wrong joint into the arm 25.

Although a male ball joint has been described, it will be apparent to a person skilled in the art that the invention is equally applicable to a female joint providing a socket adapted to receive the arm 25, which may be solid. It is an essential feature however that only one installation orientation is possible, and this is assured by the use of a through hole in one side of the outer telescopic part, and a blind hole in the inner telescopic part.

Claims

1. A pivotable link and bent arm adapted for mutual telescopic attachment, the link and arm each having a recess adapted to be aligned in a predetermined orientation and having securing means attachable to one of the link and arm, the securing means having a projection engageable closely in said recesses to retain the joint and arm at a predetermined insertion displacement and orientation.

2. A pivotable link and bent arm according to claim 1 wherein said recess comprises a through hole in the wall of the outer telescopic part and a blind hole in the inner telescopic part.

3. A pivotable link and bent arm according to claim 2 wherein said through hole and blind hole are round and of equal diameter.

4. A pivotable link and bent arm according to any preceding claim wherein the bent arm is the outer telescopic part.

5. A pivotable link and bent arm according to any preceding claim wherein said projection comprises an inwardly directed pin of a saddle clamp adapted to be secured around the joint and arm.

6. A drag link comprising a pivotable link and bent arm according to any preceding clainL Amended claims have been filed as follows A pivotable link and bent arm adapted for mutual screw-threaded and telescopic attachment, the link and arm each having a recess adapted to be aligned in a predetermined orientation and having securing means attachable to one of the link and arm, the securing means having a projection engageable closely in said recesses to retain the joint and arm at a predetermined insertion displacement and orientation and permitting transmission of end loads via the screw threading.

A pivotable link and bent ann according to claim 2 wherein said through hole and blind hole are round and of equal diameter.

6. A drag link comprising a pivotable link and bent arm according to any preceding claim.

7. A drag link comprising a pivotable link and bent arm substantially as described herein with reference to Figs. -3) and 4 of the accompanying drawings.