| Cable
Assemblies Pulley
Design:
Both Pulley
Diameter and Groove Design are crucial factors in the design of
mechanical cable assemblies, cable
assemblies, cable lanyards,
custom cable assemblies, wire rope
assemblies and pulley. Flexible
cable constructions are typically used in the
design of pulley systems. Avoid using
pulleys with smaller diameters than required,
or the life of the cable will be
reduced.
The Groove Design can be calculated by adding: 1.5 X
Diameter Tolerance (including tolerance of bare
cable or coating) plus the Maximum Cable
Diameter.
Recommended Pulley Diameter to
Cable Diameter ratios are listed
below.
|
.
|
3x7
|
7x7
|
7x19
|
|
Preferred
Minimum
|
50:1
|
42:1
|
24:1
|
|
Absolute
Minimum
|
40:1
|
30:1
|
18:1
|
Cable Assembly Pulley
Construction:
Pulleys are most
commonly made from aluminum, steel, nylon, and acetal.
Some options to consider in the construction of pulley
are sintered bronze bushings, an open or closed ball, or
roller bearings. The corrosion resistance and RPM's are
also factors in the construction of a
pulley system. Below is a chart
describing some features and uses of common
pulley and bearings.
Pulley
Construction
|
.
|
Plain
metallic
or
Thermoplastic Pulleys
|
Metallic or
Plastic Pulleys
(Sintered bronze
bearings)
|
Open free
turning or precision closed
(Lubricated ball
bearings)
|
|
Features
|
Lowest cost, light
loads, low RPM
|
Self lubricated
bearings, low cost durable, higher load,
shock resistance
|
Minimum friction,
precise tracking, medium load, high
RPM
|
|
Common
Uses
|
Low frequency drive
and lift cable applications
|
Medium RPM, load
drive, index, and lift cable
systems
|
High speed drive and
index cable systems
|
|