§393.89 Buses, Drive Shaft Protection

Question 1: For the purposes of §393.89, would a spline and yoke that is secured by a nut be considered a sliding connection?

Guidance: No. To be considered a sliding connection, the spline must be able to move within the sleeve. When the end of the spline is secured by a nut, it no longer has that freedom.

Question 2: On multiple drive shaft buses, does §393.89 require that all segments of the drive shaft be protected no matter the segments' length?

Guidance: Yes. Each drive shaft must have one guard or bracket for each end of a shaft which is provided with a sliding connection (spline or other such device).

Question 3: How does an existing pillow bearing (shaft support) on a multiple driveshaft system affect the requirement?

Guidance: It does not affect the requirement. It is part of the requirement.