GB1584661A - Ball pins - Google Patents

Description

(54) IMPROVEMENTS IN BALL PINS (71) We, SUPRA AUTOMOTIVE LIMITED, of Southern Leamington Spa, Warwickshire CV33 ODG, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to ball pins such as are used in, for example, ball and socket joints for motor vehicle track rods.

One known method of manufacturing ball pins of this type comprises the following steps: forging a metal stud to provide an enlarged head on one end thereof, turning the forged stud to shape the head thereof according to the desired configuration, usually spherical or part- spherical, and to shape the remainder of the stud, hardening or toughening the head of the stud, and subjecting the head to a finishing operation to provide the same with a smooth finish.

The object of the present invention is to provide a simplified method of manufacturing ball pins.

According to the present invention, the metal stud is initially formed with an enlarged head which is hollow and subsequently the head is roll-formed so as to provide a desired configura tion and also subject the head to a surface finishing treatment during such roll-forming operation.

In one embodiment of the invention, the hollow head is formed during a forging opera tion, e.g. cold-heading, in which at the same time as the head is enlarged, the head is formed with a blind bore or other recess so that the head is effectively hollow. Subsequently the stud can be turned to shape its shank and neck but turning of the head to shape the same is not necessary as this is effected during the roll-forming operation. As well as obviating the need for turning the head to shape, the roll-forming operation may render hardening or toughening of the head unnecessary be cause the consequent cold-working will have the effect of increasing the tensile strength of the head.

T6 promote further understanding of the invention, one example will now be described with reference to the accompanying drawing in which Figure 1 is a view of a stud immediately after forging thereof, the head being shown partly in section; and Figure 2 is a similar view but showing the head after roll-forming and burnishing thereof.

The stud shape shown in Figure 1 is produced by subjecting a length of mild steel rod or wire to a forging operation, e.g. cold-heading, so as to provide the rod or wire portion with an enlarged generally cylindrical head 10 in which a blind bore 12 is formed to render the head hollow, a cylindrical body portion 14 and a reduced diameter end portion 16. The blind bore 12 may be formed at the same time as the enlarged head is formed. The length of rod or wire so formed is then severed to form the stud shown in Figure 1. The body portion 14 of the stud is then subjected to a metal turning operation to produce the shaping shown in Figure l,i.e. a reduced neck 18 and a shank 20.

After the turning operation has been completed, the head 10 is roll-formed to a generally spherical configuration, as shown in Figure 2.

The rolls comprise two sections which are movable towards and away from one another under the control of hydraulically operable means and the sections are formed with die cavities which when the sections are brought fully together, define the desired configurå- tion for the head of the stud. By locating the head of the stud between the two sections and bringing the latter together whilst rotating them about the axis of the stud, the generally cylindrical head is gradually deformed towards the desired spherical configuration. When the die sections have been brought together, rotation is continued so that they have the effect of subjecting the surface of the head to a burnishing operation. For this purpose the working surfaces of the die sections may be suitably treated, e.g. diamond lap formed.

In some circumstances, it may be necessary to harden or toughen the head as an intermediary step between turning and roll-forming.

However, this may not be necessary in all cases as the cold-working occurring during roll-forming will tend to harden or toughen the head.

At anxappropriate stage during the manufacturing process, the reduced diameter end portion 16 will be subjected to a thread-rolling operation.

As described above, the roll-forming opera tion is carried out subsequent to the turning operation. It is conceivable, however, that this sequence of operations may be reversed.

Also whilst it is preferred to bore or otherwise recess the head simultaneously with the formation of the enlarged head, it will be understood that these operations may be carried out separately.

WHAT WE CLAIM IS: 1. A method of manufacturing a ball pin in which a metal stud is initially formed with an enlarged head which is hollow and subsequently the head is roll-formed so as to provide a desired configuration and also subject the head to a surface finishing treatment during such roll-forming operation.

2. A method as claimed in Claim 1 wherein the hollow head is formed during a forging operation, e.g. cold-heading, in which at the same time as the head is enlarged, the head is formed with a blind bore or other recess so that the head is effectively hollow.

3. A method as claimed in Claim 1 or 2 wherein the roll-forming operation is carried out using rolls comprising two sections which are movable towards and away from one another under the control of hydraulically operable means and the sections are formed with die cavities which when the sections are brought fully together, define the desired configuration for the head of the stud.

4. A method as claimed in Claim 3 in which the working surfaces of the die sections are adapted to subject the surface of the head to a burnishing operation.

5. A method of manufacturing a ball pin substantially as hereinbefore described with reference to the accompanying drawing.

6. A ball pin when manufactured by the method of any one of Claims 1-5.

by the following statement:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. tion is carried out subsequent to the turning operation. It is conceivable, however, that this sequence of operations may be reversed. Also whilst it is preferred to bore or otherwise recess the head simultaneously with the formation of the enlarged head, it will be understood that these operations may be carried out separately. WHAT WE CLAIM IS:

1. A method of manufacturing a ball pin in which a metal stud is initially formed with an enlarged head which is hollow and subsequently the head is roll-formed so as to provide a desired configuration and also subject the head to a surface finishing treatment during such roll-forming operation.

2. A method as claimed in Claim 1 wherein the hollow head is formed during a forging operation, e.g. cold-heading, in which at the same time as the head is enlarged, the head is formed with a blind bore or other recess so that the head is effectively hollow.

3. A method as claimed in Claim 1 or 2 wherein the roll-forming operation is carried out using rolls comprising two sections which are movable towards and away from one another under the control of hydraulically operable means and the sections are formed with die cavities which when the sections are brought fully together, define the desired configuration for the head of the stud.

4. A method as claimed in Claim 3 in which the working surfaces of the die sections are adapted to subject the surface of the head to a burnishing operation.

5. A method of manufacturing a ball pin substantially as hereinbefore described with reference to the accompanying drawing.

6. A ball pin when manufactured by the method of any one of Claims 1-5.

by the following statement: