This invention relates to a fork for the starter motor drive assembly of an internal combustion engine.. The fork is intended to thrust the drive assembly to mate with the ring gear of the engine, during cranking and starting attempts.
Conventionally, the fork which is made of a material, such as, glass filled polyamide (PA6, PA66) among others, does not have an acceptably long wear life, since it has to undergo repeated contact with the drive assembly during engagement and retraction operations.
There have been proposals for manufacture of the fork from wear resistant materials. However, these proposals have not been found feasible since the cost of the fork, as a whole, would go up. Besides such proposals would result in wasteful expenditure, since it is not the whole of the fork that would need to be made resistant to wear.
This invention, therefore, seeks to avoid the above mentioned drawbacks.
According to this invention, the fork for the starter motor drive assembly of an internal combustion, intended for actuating drive assembly of the starter motor to mate with the ring gear of the engine, comprises a pair of limbs, the inner side of each limb at its free end having at least one wear resistant insert integrally seated in a recess whereby the said insert alone comes into contact with the drive assembly while starting the engine.
The fork proposed herein will now be described in further detail by referring to the accompanying drawings which illustrate by way of example, and not by way of limitation, one of possible embodiments of this invention,
Fig. 1 illustrating the known fork in sectional elevation
Fig.2 illustrating the said embodiment in sectional elevation with insert in place
Fig. 3 illustrating a separate view of the insert of Fig. 1
Fig. 4 illustrating an alternative version of the insert of the said embodiment
The fork F comprises a pair of limbs L,L. The inner side of each limb, at its free end, has two wear resistant inserts J integrally seated in recesses R such that the said inserts alone come into contact with the drive assembly of the starter motor during engagement and retraction operation of a starting cycle. Thus the working life of the fork is enhanced since the body of the fork does not directly contact the drive assembly, but it is only the wear resistant inserts J on the two limbs that do so.
As a variation of the circular insert shown in Fig. 2 and 3, it is possible to have only a segment of a circle, such as, one half of the insert J as shown in Fig. 4 on the retraction side of the limbs of the fork.
In the embodiment illustrated the inner side of each limb L has a ledge V in which the recesses are provided. Each insert is so positioned in the recess that the top face T of the insert is flush with the top M of the ledge,
One of the ways of integrally seating the insert J in the recess R is by moulding the insert J along with the whole fork F, whereby the said insert becomes an integral part of the recess.
The high wear resistant material of which the insert can be made is exemplified by polyamide, PEEK among others. The embodiment above mentioned has been made from the polyamide material commercially known as VESPAL (Trade Mark of DuPont).
It will be appreciated from the foregoing description that various other embodiments of this invention are possible without departing from its scope and ambit.

We Claim:
1. A fork for the starter motor drive assembly of an internal combustion, intended for actuating the drive assembly of the starter motor to mate with the ring gear of the engine, comprising a pair of limbs, the inner side of each limb at its free end having at least one wear resistant insert integrally seated in a recess whereby the said insert alone comes into contact with the drive assembly while starting the engine.
2. A fork for the starter motor drive assembly of an internal combustion engine as claimed in Claim 1 wherein the inner side of each limb at its free end has a ledge on which the recess is located.
3. A fork for the starter motor drive assembly of an internal combustion engine as claimed in Claim 1 or Claim 2 wherein the insert is integrally seated in the recess by moulding.
4. A fork for the starter motor drive assembly of an internal combustion engine as claimed in any one of the Claims 2
and 3 wherein the top surface of each insert is flush with the top of the ledge.
5. A fork for the starter motor drive assembly of an internal combustion engine as claimed in any one of the preceding Claims wherein the insert is circular.
6. A fork for the starter motor drive assembly of an internal combustion engine as claimed in any one of the preceding Claims 1 to 4 wherein the insert is a segment of a circle.
7. A fork for the starter motor drive assembly of an internal combustion engine substantially as herein described witrh reference to, and as illustrated in, the accompanying drawings.