GB2308155A

GB2308155A - A transverse load bearing ball joint

Info

Publication number: GB2308155A
Application number: GB9525427A
Authority: GB
Inventors: Michael John Mcdermott
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-13
Filing date: 1995-12-13
Publication date: 1997-06-18
Also published as: GB9525427D0

Description

JOINT This invention relates to a spherical joint.

A spherical joint is a well known mechanical component used to connect elements while allowing angular motion of one element relative to another. It comprises a ball, attached to one of the elements, which is free to move in a housing attached to the other element. The outer surface of the ball and the inner surface of the housing which contacts the ball are, in the regions where contact between them can occur when the joint is articulated, of spherical forms which are made closely fitting to minimise the possible relative lateral movement of the connected elements. The ball is bored along a diameter to allow it to be rigidly attached to one of the elements. In one form of spherical joint, known as a rod-end, the housing incorporates a threaded section which allows it to be rigidly and removably attached to the other element.

The design of a rod-end makes it most suitable for use in applications where the direction of the principal load transmitted by the spherical joint is along the axis of the threaded section of the housing. The design is less suitable for use where there is a component ofthe load perpendicular to this axis because the ability ofthe threaded section to withstand a bending load without failing is in many applications less than its ability to withstand a tensile or compressive load. This restricts the application of rodend joints to those in which the load is primarily along the axis of the threaded section.

According to the present invention there is provided a spherical joint in which the housing incorporates means of applying transverse loads direct to the housing near to the centre of the ball so reducing or eliminating the bending stress in the threaded section of the housing. The invention may be used in applications where a rod-end of similar dimensions would be insufficiently strong.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which Figure 1 shows in perspective the joint in the present invention. Figure 2 shows the arrangement of a rod-end in an application in which it is subjected to a load with a transverse component. In Figure 2 the transverse load F applied to the ball produces a bending moment, because of the overhang X of F x X in the threaded section of the housing. The bending moment produces tensile and compressive stresses in the threaded section. Figure 3 shows the present invention in a configuration in which it can be subjected to a transverse load.

The ball 12 is free to rotate in the housing 13. The bore 16 allows the ball to be attached to an element by a bolt and nut for example. The threaded section 14 is provided for the attachment of an external element 17 and the bore 15 permits the attachment, by a bolt and nut for example, of a second element 18. The force F produces reactions primarily along the longitudinal axes of the elements 17 and 18. 19 denotes the axis joining the centres of the bores 15 and 16. Only small bending moments, their magnitude dependent on the misalignment of the axis of element 18 and the axis 19, exist in the threaded section attaching to element 17, and in the region of the bore 15 attaching element 18.

Claims

1. A spherical joint comprising a ball and a housing with closely fitting spherical contacting surfaces in which the ball is provided with a means of removably attaching one element and in which the housing is provided with means of removably attaching two or more elements.

2. A spherical joint as claimed in Claim 1 in which the housing is provided with a threaded section for attaching one element and bores for attaching the second and any further elements.

3. A spherical joint as claimed in Claim 1 in which the housing is provided with two threaded sections for attaching two elements.

Amendments to the claims have been flied as follows

1. A spherical joint comprising a ball and a housing with closely fitting spherical contacting surfaces in which the ball is provided with a bore as the means of removably attaching one element and in which the housing is provided with means of removably attaching two or more elements.