GB2299368A

GB2299368A - Socket arrangement for a ball and socket joint

Info

Publication number: GB2299368A
Application number: GB9506539A
Authority: GB
Inventors: Ivor John Jauncey
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-30
Filing date: 1995-03-30
Publication date: 1996-10-02
Anticipated expiration: 2015-03-30
Also published as: GB2299368B; GB9506539D0

Abstract

In a socket arrangement for a ball and socket joint comprising a housing 6 for accommodating a ball member 4 and a segmented locking member 8 for engaging the ball member and the housing to lock them together, the housing includes stop means 24 which limit the extent to which the ball member can be inserted into the housing. The stop means may comprise arcuate bearing surfaces against which the ball member engages during articulation. The locking member preferably includes three legs 40 and has a first detent position in which a rib 44 at a distal end of each leg 40 engages a first recess 18 in the housing to hold the locking member in a partially engaged position which permits the ball member 4 to be pushed against a stop surface 26 of the housing. Pushing the locking member fully into engagement with the housing causes the legs 40 to be urged against the ball member and enter a second detent position in which ribs 44 each engage a second recess 22 in the housing, and a second rib 42 on each leg 40 engages recess 18. This arrangement facilitates assembly of the joint.

Description

BALL JOINT The present invention relates to ball joints of the type used commonly in the automotive industry for interconnection of members in such a manner that a multiple degree of freedom of movement of the interconnected members is possible.

Such ball joints generally include a ball member which is slidingly engageable with a recess in a complementary housing. If the ball member and housing are engaged simply by means of the ball member being forced into a resilient housing the force required for interengagement is high. Alternatively, if the design is adapted to reduce the required interengagement force then the components may not be securely interconnected and accordingly will be liable to accidental separation.

Various attempts have been made in the past to design ball joints which are easy to assemble and disassemble and yet provide a secure retention of the ball member in the housing when assembled. One example of such a prior art ball joint is described in EP-A-O 271 676 in which a slotted locking sleeve is interposed between the ball member and housing and which engages the housing by means of camming projections. A further example is described in DE-A-3308457 in which a slotted sleeve is also interposed between the ball member and the housing and which engages the housing by means of stepped locking projections.In both of these prior art ball joints the ball member does not engage the housing at all which means that in order to urge the locking members into full engagement with the housing it is necessary to support the housing while the locking member is urged into full engagement therewith.

This operation can be difficult to perform in restricted spaces and often leads to undesirable twisting or bending forces being placed on the housing.

An object of the invention is to provide a ball joint which overcomes the above disadvantages and can be easily assembled, and preferably also disassembled, and yet which affords secure retention of the ball member in the housing when fully assembled.

Thus according to the invention there is provided a ball and socket joint comprising a ball member, a housing for accommodating the ball member and a segmented locking member for engaging the ball member and the housing to lock them together wherein the housing member includes stop means which limit the extent to which the ball member can be inserted into the housing.

With such an arrangement the locking member may be fully engaged with the housing and the ball member by simply urging the locking member towards the ball member.

No support of the housing is necessary as it is supported by engagement of its stop means with the ball member.

Quick and easy installation of the ball joint, particularly in inaccessible locations is thereby facilitated. A reversal of this process is also possible thus facilitating separation of the ball member from the housing when required.

So that deformation of the stop means during joint assembly is unlikely to occur and so that the ball member and housing can be in a variety of orientations during assembly the stop means preferably comprises arcuate bearing surfaces against which the ball member slidingly engages during joint articulation. More preferably the stop means prevents the ball member passing into the housing further than its final assembled location.

The housing preferably includes guiding means which urge locking member segments into engagement with the ball member as the locking member becomes fully engaged with the housing. By providing a locking member which is segmented, deformation of parts of the locking member which engage the ball member can be facilitated. Furthermore the provision of guiding means in the housing for urging the locking member segments into engagement with the ball member as the locking member becomes fully engaged with the housing provides a progressive ball member securing force which increases to a maximum when the locking member is fully engaged.

In order that this ball member securing force increases in a steady manner the guiding means preferably comprises one or more guiding surfaces which taper inwardly towards an adjacent outer surface of the housing.

Conveniently these guiding surfaces substantially constitute at least part of a frusto-conical surface. The guiding surfaces may comprise three or more separate faces each of which constitutes part of the surface of a cone or sphere.

So as to assist assembly of the joint and/or full engagement of the locking member and the housing, the joint preferably includes detent means operable between the housing and the locking member to hold the locking member in a particular position with respect to the housing.

Preferably the detent means includes a first detent for holding the locking member in a partially engaged position in the housing in which position the ball member can be engaged with the housing. With such an arrangement the ball joint can be provided in a semi-assembled state with the locking member partially engaged with the housing.

The ball member can then be pushed into the housing without dislodging the locking member, and the locking member then pushed into full engagement with the housing and ball member.

In its partially engaged position, segments of the locking member preferably extend past a transverse centre line of a ball portion of the ball member in order that the ball member will be held in the housing relatively securely even when the locking member is only in its partially engaged position.

More preferably the detent means also includes a second detent for retaining the locking member fully engaged with the housing so that accidental disengagement of the locking member from its fully engaged position can be precluded.

In order to make production of the housing and the locking member as simple as possible, the detent means preferably includes a projection which is interengageable with a recess each of which is located on one of the housing and the locking member respectively.

Preferably the locking member includes a cap portion with segment legs which extend along and are displaced from a central axis of symmetry of the locking member and which engage the ball member when the locking member is fully engaged with the housing. With such an arrangement the segment legs can easily flex as the locking member is partially or fully engaged with the housing.

Furthermore, easy alignment of the central axis of the locking member with that of a ball member accommodating recess in the housing can be provided by engagement of each leg with a complementary recess in the housing.

Particularly secure retention of the ball member in the housing when the locking member is in both its partially and fully engaged position is achieved when the locking member legs occupy between 20% and 80% and more preferably between 40% and 60% of the circumferential extent of the locking member.

The ball joint components are preferably configured so as to effect resilient gripping of the ball portion when the locking member is fully engaged with the housing so as to prevent any undesirable vibrational movement of the ball member relative to the housing.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a partial cross-section through a ball joint constructed according to the invention showing the parts separated, Figure 2 is a view similar to Figure 1 showing the parts in a partially engaged configuration, Figure 3 is a view similar to Figure 1 showing the parts in a fully engaged configuration, and Figure 4 is a transverse cross-section on the line AA of the ball joint shown in Figure 3.

Referring to Figure 1, the ball joint 2 includes three components. These are, a ball member 4, a housing 6 and a locking member 8.

The housing 6 has a through aperture 10 with a central axis 12 and three outwardly extending recesses 14 (see figure 4) each of which subtends 600 at the central axis 12. Inwardly facing surfaces of the recesses 14 taper towards a lower portion of the housing 6 and constitute guiding surfaces 16 for the locking member 8. Each recess 14 includes a first circumferentially extending recess 18 positioned approximately centrally with respect to the housing and below a raised land 20 and a second circumferentially extending recess 22 located at a lower end of the corresponding guide surface 16. Between the recesses 14 circumferentially extending bearing surfaces 24 are provided, an upper region of each of which has a partspherical surface 26 and lower region of each of which has part-cylindrical surface 28.Above the bearing surfaces 24 a shallow cylindrical recess 30 is provided for accommodating part of the locking member 8 and below the bearing surfaces a frusto-conical opening 32 is provided for guiding the ball member 4 into the housing 6 and allowing a high degree of articulation of the joint when assembled (560).

A threaded bore 34, a central axis of which is perpendicular to the central axis 12 of the through aperture 10 is provided to facilitate connection of the housing to other components.

The locking member 8 includes a central axis 38, a disc like cap portion 36 which is perpendicular to the central axis 38 and three legs 40 which extend substantially perpendicularly from the cap portion 36.

Each leg 40 subtends 600 at the central axis 38 and is provided with a first circumferentially disposed rib 42 positioned between the distal end of the associated leg 40 and the cap portion 36 and a second circumferentially disposed rib 44 situated substantially at a distal end of the associated leg 40. An inwardly facing surface 46 of each leg 40 is constituted by an upper part-spherically shaped region 48. The lower part of each such inwardly facing surface 46 is constituted, when the locking member is not installed in the housing, by a substantially partcylindrical region 50. The distal ends of the legs 40 are however deformed upon ball joint assembly as described below.

The housing and locking member may be made from any suitable resilient plastics material such as high density polyethylene or PET.

The ball member 4 is a conventional steel ball member including a substantially spherical ball portion 52, a threaded shank 54 and a hexagonal spanner engagement portion 56.

The manner in which the ball joint is assembled will now be described with reference to Figures 1 to 4.

Firstly the locking member 8 and housing 6 are disposed with their respective central axes 38 and 12 coincident and are brought together so that each leg 40 passes onto a corresponding recess 14 in the housing 6 until the second rib 44 on each leg 40 passes over land 20 and snaps into the associated first recess 18. This engagement constitutes the first detent. At this partially engaged position of the locking member 8 the distal end of each leg 40 extends slightly past a transverse centre line 58 of the housing 6.

The ball portion 52 of the ball member 4 is then passed into the opposite side of the housing from the side to that to which the locking member 8 was inserted through the frusto-conical opening 32. Insertion occurs until the ball portion 52 comes into contact with inner surfaces of the distal ends of the legs 40, at which point additional force will be required to snap the ball into its fully inserted position as shown in Figure 2. At this point the ball portion 52 comes to rest against the part-spherical surfaces 26 of the housing bearing surfaces 24 and is held securely in place by the distal ends of the legs 40.

The locking member 8 and/or the housing 6 can be held while this operation is performed. If the locking member 8 is held, the engagement of the second ribs 44 in the first recesses 18 prevents any undesired displacement of the housing 6. Alternatively if the housing 6 is held, the second ribs 44 and first recesses 18 prevent any undesired movement of the locking member 8.

The locking member 8 can then be driven into its fully engaged position which is illustrated in Figure 3.

The housing 6 or more preferably the ball member 4 is restrained as this operation is performed. As the locking member 8 is moved towards the position shown in Figure 3 the second rib 44 on each leg 40 rides out of its associated first recess 18 and slides down the associated guiding surface 16 which urges the distal end of the leg 40 to be resiliently inwardly deformed and follow round an inwardly tapering portion of the ball portion 52 of the ball member 4. Finally the first and second ribs 42 and 44 on each leg 40 snap into their associated respective first and second recesses 18 and 22 (which jointly constitute a second detent) and the cap portion 36 of the locking member 8 seats itself in the cylindrical recess 30 in the housing 6 with its upper surface flush with the adjacent housing outer surface. The ball member thereby becomes firmly locked into the housing and can only be removed with reasonable force if the locking member 8 is prised out of the housing 6 at least as far as its partially engaged position shown in Figure 2.

Preferably the exterior surface of each leg 40 includes a groove 60 adapted to snugly receive the associated land 20 of the housing 6 to improve the fit of the locking member in the housing.

Although reference has been made to contact between the ball member 4 and the housing it is possible that a layer of material (eg low friction material) may be interposed between these members.

Claims

CLAIMS:

1. Socket arrangement for a ball and socket joint comprising a- housing means for accommodating a ball member and a segmented locking member for engaging the ball member and the housing means to lock them together wherein the housing means includes stop means which limit the extent to which the ball member can be inserted into the housing means.

2. The socket arrangement claimed in claim 1 wherein the stop means comprises arcuate bearing surfaces against which the ball member slidingly engages during joint articulation.

3. The socket arrangement claimed in claim 1 or 2 wherein the stop means prevents the ball member passing into the housing means further than its final assembled location.

4. The socket arrangement claimed in any preceding claim wherein the housing means includes guiding means which urge locking member segments into engagement with the ball member as the locking member becomes fully engaged with the housing means.

5. The socket arrangement claimed in claim 4 wherein the guiding means comprise one or more guiding surfaces which taper inwardly towards an adjacent outer surface of the housing means.

6. The socket arrangement claimed in claim 5 wherein the one or more guiding surfaces substantially constitute at least part of a frusto-conical surface.

7. The socket arrangement claimed in any preceding claim including detent means operable between the housing means and the locking member to hold the locking member in a particular position with respect to the housing means.

8. The socket arrangement claimed in claim 7 wherein the detent means includes a first detent for holding the locking member in a partially engaged position in the housing means in which position the ball member can be engaged with the housing means.

9. The socket arrangement claimed in claim 8 wherein in its partially engaged position segments of the locking member extend past a transverse centre line of a ball portion of the ball member.

10. The socket arrangment claimed in claim 7, 8 or 9 wherein the detent means includes a second detent for retaining the locking member fully engaged with the housing means.

11. The socket arrangement claimed in any one of claims 7 to 10 wherein the detent means includes a projection which is interengageable with a recess each of which is located on one of the housing means and the locking member.

12. The socket arrangement claimed in preceding claim wherein the locking member includes a cap portion with segments legs which extend along and are displaced towards a central axis of symmetry of the locking member and which engage the ball member when the locking member is fully engaged with the housing means.

13. The socket arrangement claimed in claim 12 wherein the legs occupy between 20% and 80% of the circumferential extent of the locking member.

14. The socket arrangement claimed in claim 13 wherein the legs occupy between 40% and 60% of the circumferential extent of the locking member.

15. A socket arrangement substantially as herein described with reference to the accompanying Figures.