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Rotary and Stationary Joint Kits
Introduction
The joint kits are designed as a convenient, repeatable, variable stiffness joint for assessing the
performance of torque tools. They can be used with the Ingersoll-Rand stationary (static) or
rotary transducers.
Each kit may be assembled in different ways to vary the stiffness of the joint. Reference Table 1,
to select from the available options. Care should be taken to ensure that the maximum torque
for the joint is not exceeded. Please note that the joint kit is not designed to provide an exact
joint stiffness and that the rates shown in Table 1 are given as rough guide only.
Joint Assessment
The first task is to choose the stiffness of the joint that the tool will be used to assemble. This is
best done with a torque wrench on an actual production part. If available an angle measurement
protractor may be used, but this is not essential. Tighten the fastener until it is snug, note the
torque Ts in Nm (or lbft). Tighten to the required target torque Tf Nm (or lbft), and note the angle
of rotation E in degrees. The required joint stiffness may now be calculated. The resulting units
are degrees per Nm (or degrees per lbft).
E / (Tf-Ts) Ts = Snug Torque
Tf = Target Torque
E = Angle
It should be noted that for packaging convenience Joint Kits will be delivered assembled with full
stacks of belleville washers. The spacers will be bagged separately. The Joint Kits DO NOT
represent a usable joint without adjustment to the required stiffness. A Pictorial guide to the
description of components is shown in Figure 2. Table 2 shows the parts available for each
model.
Joint Assembly
Having selected the required joint stiffness from Table 1, count out the number of Belleville
washers required for the first and second stacks. Grease each washer and assemble the first
stack around the bolt, such that the internal diameter rests against the shoulder of the bolt.
Invert the second stack such that the outside diameters of the last and first washers in the two
stacks touch. If only one stack is to be fitted, it should be mounted such that the external
diameter rests against the bolt shoulder. Select and fit the spacer required to complete the joint.
After greasing the bearing surface, slide the assembly into the external sleeve, fit the end collar
and secure by applying the retaining clip.
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