Cam Couplings
Maintainability is one of the most important characteristics of CNC machines. Therefore, when assembling motion circuits, a rigid direct connection (welding, pressing, etc.) between the stepper motor shaft and the ballscrew screw is unacceptable. Couplings are used to transmit torque.

Coupling type:
Blind – Solid cylinder with grooves for crimping the shaft;
Flanged – two half-couplings assembled with rigid mounting, adjustable by the relative position of the flanges;
Bellows – couplings with grooves perpendicular to their axis (nowadays versions with spiral grooves are more common);
cams – couplings with elastic compensation inserts.
Advantages of claw clutches over other types
Blind couplings require precise coincidence of the axes of the motor shaft and ball screw, which is difficult to achieve in practice. Flanged types allow for shaft and screw misalignment; they are adjusted once during installation, but when the structure is dismantled (replacing the coupling or ball screw, repairing the motor), the adjustment process must be repeated. Bellows and cam couplings do not have this disadvantage. However, cams transmit more torque from the shaft to the screw than bellows, and they dampen vibrations better due to the elastic insert. In addition, they are more robust – split (bellows) couplings can break due to sharp changes in rotational speed, while flexible cam inserts absorb the resulting shock. The same damping effect extends the service life of the gearbox.

Another advantage: given the interchangeability of coupling elements with the same outside diameter, it is much easier to select the required halves according to the inside diameter if the ball screw and shaft dimensions do not match. In practice, however, given the low cost and wide range of couplings, it is often possible to choose a ready-to-assemble version and replace the entire coupling if one half is worn out.