Under normal conditions, machines receive periodic inspections and their overall
condition is recorded. Such inspections usually include the drum, sheaves and any
other parts that may come into contact with the wire rope and subject it to wear. As
an additional precaution, rope related working parts, particularly in the areas described
below, should be re-inspected prior to the installation of a new wire rope.
The very first item to be checked when examining sheaves and drums is the condition
of the grooves (Figs. 35, 36 and 37). To check the size, contour and amount of
wear, a groove gauge is used. As shown in Figure 35, the gauge should contact the
groove for about 150° of arc.
Two types of groove gauges are in general use and it is important to note which of
these is being used. The two differ by their respective percentage over nominal rope
diameter.
For new or re-machined grooves, the groove gauge is nominal plus the full oversize
percentage. The gauge carried by most wire rope representatives today is used for
worn grooves and is made nominal plus 1/2 the oversize percentage.
This latter gauge is intended to act as a sort of “no-go” gauge. Any sheave with a
groove smaller than this must be re-grooved or, in all likelihood, the existing rope will
be damaged.
When the sheave is re-grooved it should be machined to the dimensions for “recommended
minimum new groove” given. This table lists the requirements for new or
re-machined grooves, giving the groove gauge diameter in terms of the nominal wire
rope diameter plus a percentage thereof. Similarly, the size of the “no-go” gauge is
given, against which worn grooves are judged. Experience has clearly demonstrated
that the service life of the wire rope will be materially increased by strict adherence to
these standards.
