(C) Allowing For Thermal Expansion

To allow for the thermal expansion of a rotating shaft and avoid possible binding (a), it is preferable to mount the ball bearings In lapped holes (b) with one bearing held In postion by a split retaining ring and the other bearing allowed to float axially in the smooth machined bore.

In the case of collars which control the axial positions of a shaft (a), it Is preferable to install the collars at one end of the shaft only, thereby allowing for thermal expansion (b).

(d) Allowing For Wear In Design And Assembly

In order to loosen the tolerances on the link lengths b, c, d, of a four-bar linkage, It is sometimes desirable to provide for an adjustable floating link. The length of the floating link can be adjusted, for example, by means of a three piece threaded connection (b), consisting of a nut and one left- and one right-handed threaded link.

In the case of a rotating shaft with a precision assembly (a), a split bushing tapered towards the exit side (b) permits takeup of wear and thus prolongs the service life of the assembly.

Another Illustration of wear compensation by means of an extra tapered key (b), which also eases the tolerances on the dovetail.