Abstract: Rotational control apparatus (A) in the preferred forms of fan clutches is disclosed including shoulder bolts (78) extending through axially extending voids (146) formed in axially extending portion (66) and flange (76) of first and second shell housings (62, 68). The shoulder bolts (78) secure the shell housings (62, 68) together to prevent relative movement therebetween. The apparatus (A) further includes a piston (80) having tabs (144) extending from the outer periphery thereof into the voids (146) and including openings having bushings (134) therein for slideable receipt on the shoulder bolts (78). Springs (138) are mounted on standoffs (210) extending in the voids (146) and abutting with the shoulder of the shoulder bolts (78).

Abstract: A rotational control apparatus in the preferred form of a fan clutch is disclosed including a friction disc portion slidably mounted and rotationally related by splines on a hub in turn rotatably mounted on a fixed shaft. The splines are formed on a radially outermost portion of the hub. A washer abuts with a shoulder formed in the hub at the intersection of a radially reduced portion with the radially outermost portion and with a retainer on the free end of the radially reduced portion sandwiches a spring in a compressed condition on the reduced portion. In an assembled relation, the friction disc portion abuts with the washer such that the spring biases the friction disc portion. The friction disc portion may be slid from the hub without removal of the hub from the shaft and with the spring retained on the hub by the washer. Both sides of the friction disc portion taper together such that the thickness therebetween decreases with the radial spacing from the rotational axis.