GB2122723A - Universal transmission joint - Google Patents

Abstract

In a universal joint of the kind in which the input and output members (1b, 2b) can be angularly adjusted relative to one another, said members are mounted on half-balls (1, 2) formed with arcuate slots (1a, 2a) which face and extend at right angles to one another and receive matching projections on a crosshead (3) which transmits motion from one member to the other and is formed to simulate two segments of a cylinder each of which is more than half the size of the cylinder and so embraces the other segment that its ends (3a) extend in a common plane on opposite sides of the other segment and are rounded in concentricity with the arcuate external surface of the other segment. The rounded ends (3a) are rotatably seated in half-bearings (10) which are interposed between each segment of the crosshead (3) and the associated half-ball (1 or 2). <IMAGE>

Description

SPECIFICATION Universal transmission joint This invention relates to universal transmission joints.

The principal object of the invention is to simplify the construction of joints of this type and thus obtain transmission of movement between inlet and outlet elements at different angles to each other, in the same direction and at the same speed, by means of a single connection.

The joint of the invention is designed to transmit forces through the medium of only three elements, two of which are identical and are coupled together within two half bearings contained in a tubular casing. One of the two identical elements constitutes the receiver and the other the transmitter and each one is capable of individual adjustment in any direction with respect to the geometric axis of the assembly, which implies a joint angular variation upwards of 400. The key-piece of the assembly is a crosshead which has parts which match and cooperate with complementary parts of the two identical elements to transmit rotation from one to the other while allowing individual angular adjustment of each one relative to the other.

According to one aspect of the present invention, two further elements are interposed between the crosshead and two half-balls constituting the transmission elements, said members acting as self-lubricating bearings and as axial locating members. In this manner, a running freedom is given to the functioning of the homokinetic joint, thus avoiding the risk of jamming.

Grooves are preferably formed in the sides of the half-balls to receive ribs projecting from said bearing members to secure these bearings and avoid all possibility of abnormal displacement.

The invention also provides an improved form of crosshead which is considerably strengthened and at the same time, facilitates joint movements.

In order to avoid accidental slipping or sliding of the components of the joint casing relative to one another, two rings are interposed between the bearings for the half-balls and the tubular casing, which lock onto the latter and provide a permanent union. The casing is also deformed to provide an axially extending rib which projects inwardly and, on assembly, is received in external grooves formed in said rings, thereby preventing the rotation thereof with respect to the aforesaid casing.

For a better understanding of the invention and merely by way of example, one embodiment will be described with reference to the accompanying drawing wherein: Fig. 1 illustrates the assembled universal joint, seen in longitudinal section and with the input and output shafts at an angle to one another; Fig. 2 is an exploded view of the joint; Fig. 3 is a view in the direction of the arrow "A" in Fig. 2; Fig. 4 is a view in the direction of the arrow "B" in Fig. 2; Fig. 5 is a view in the direction of the arrow "C" in Fig. 2; Fig. 6 is a view in the direction of the arrow "D" in Fig. 5; Fig. 7 is a perspective view of the crosshead shown in Figs. 2, 5 and 6; Fig. 8 is a view in the direction of the arrow "E" in Fig. 2; and Fig. 9 is a section on the line "F" in Fig. 2.

Referring to the drawing, two half-balls 1, 2 are provided with arcuate recesses 1 a, 2a which, on assembly, are arranged face to face and at right angles to one another and house corresponding portions of a crosshead 3.

The crosshead 3 is formed in one piece and simulates two interlocking segments of a cylinder.

extending in planes which intersect at 900. Each segment matches one of the recesses 1 a, 2a in the half balls 1, 2 and is more than half the size of the complete cylinder. The ends 3a of each segment extend in a common plane on opposite sides of the other segment and are rounded in concentricity with the arcuate surface of the other segment. The rounded ends 3a are rotatably seated in half bearings 10 which are interposed between each segment of the crosshead 3 and the associated half ball 1 or 2. Said half bearings 10 are each provided with a plane skirt 1 Oa which is inserted in the corresponding recess 1 a, 2a and acts as a spacer and at the same time, as a sliding seat for the side surfaces of each segment of the crosshead 3, which surfaces are plain and parallel to their guidance is achieved without any metalto-metal contact.In order to secure correct positioning of the half bearings 10 and the half balls 1 , 2, the former are provided with projecting ribs lOb which are received in corresponding grooves 1 d, 2d in the half-balls.

From the above description, it will be clear that the recesses 1 a, 2a are wider than the segments of the crosshead 3, so that at no time whatsoever is there any direct contact between said crosshead and said half-balls 1, 2 and all forces will be transmitted through the four half bearings 10 interposed therebetween in their dual function as seats and friction members.

Each half ball 1, 2 is extended by a shaft 1 b, 2b for the reception and/or transmission of rotary motion, which shafts may perform different functions, depending upon the application of the homokinetic joint. A spherical portion 1 c, 2c forming the head of each half-ball is seated in a ball socket 4 which, on assembly, is situated behind each half-ball and the two sockets are maintained in position by a tubular casing 5, the edges of which are laterally cramped to ensure a permanent assembly. This assembly, which has the advantage that neither of the sockets 4 can rotate inside the casing 5, because each socket 4 is provided with an external axially extending slot 4b, which receives a rib 5a on the wall of the tubular casing 5.

The transmission of motion is carried out by the crosshead 3, the sides of the segments of which engage the side walls of the recesses 1 a, 2a in the half-balls 1, 2, through the intermediary of the plain skirts 1 Oa of the half bearings 10 which, at the same time, provide seats for the rounded ends 3a of said segments to enable them to carry out the rotation which determines the amount of angular adjustment to which the aforesaid halfballs can be subjected in planes which intersect at 900, thus fulfilling the functions required of a homokinetic transmission joint.

The assembly has been designed to provide a degree of elasticity in the joint without affecting its efficient functioning and with this in mind, adjustment is effected with the aid of two toroidal rings 11 which are located in the angles formed by the cramped edges of the casing and interposed between the casing 5 and the rear beveled edges 4c of the bearings 4.

The sizes, shapes, material and other inessential features of the joint may be varied without departing from the scope of the appended

Claims (5)

claims. CLAIMS

1. A universal joint in which the transmission of force is carried out by only three elements in the form of a crosshead and two identical half-balls which are coupled together inside two half-ball sockets mounted in a tubular casing, the edges of which are laterally cramped to partly close the ends and ensure permanent assembly of the parts, characterised in that the crosshead, which is interposed between the two half-balls, has the shape of two segments of a cylinder each of a size greater than half the size of the cylinder, which segments intersect one another in such a manner that the ends of each segment lie in a common plane on opposite sides of the other segment with the axis of curvature of their rounded ends intersecting the axis of curvature of the ends of the other segment and the surfaces of their rounded ends concentric with the arcuate external surface of the other segment, said rounded ends being rotatably seated in two half bearings, arranged between each segment of the crosshead and the associated recesses in the half-balls, each of said half bearings being provided with a plain skirt projecting therefrom into one of said recesses and acting as a spacer and at the same time, as a guide for the lateral surfaces of one of the segments of the crosshead, eliminating all metalto-metal contact.

2. A universal joint, as claimed in Claim 1, characterised in that, in order to ensure that each pair of half bearings is correctly positioned in relation to its corresponding half-ball, the former is provided with projecting ribs which enter slots in said half-balls and hold them stationary in their dual function of seating and friction members.

3. A universal joint, as claimed in Claim 1, characterised in that each of the half-ball sockets in which the half-balls are housed is provided with an external axially extending slot which receives a rib projecting from the wall of the tubular casing and common to the two half-ball sockets.

4. A universal joint as claimed in any one of Claims 1 to 3, characterised in that elasticity of adjustment of the components of the joint is provided by means of two toroidal rings which are arranged in the internal angles formed by the cramped edges of the casing and interposed between the casing and rear beveled edges of the half-ball sockets.

5. A universal joint, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.