The ends of round belts are usually joined by means of cylindrical hooks and eyes, which are threaded so as to screw on to the end of the belt, but for twisted round belts it is better to place in the centre of the belt a small core of soft wood. The ends of the belt should be slightly tapered, and the hook and eye screwed firmly home. Sometimes from the smallness of the pulleys the inflexibility of the hook and eye becomes objectionable, and a simple hook is employed on solid round belting.
The length of twisted round belting may be altered by twisting or untwisting it, which renders it unnecessary to cut the belt for a small amount of shortening.
Round belts should bear upon the sides, and not on the bottom of the pulley-groove, which increases their transmitting power. Thus, if the groove is a semicircle of the same radius as is the belt when new, the stretch of the belt as it wears decreasing its diameter, it will then touch only on the bottom of the groove. Furthermore, when the belt bears on the sides only of the groove it becomes wedged to a certain extent in the sides of the pulley groove.
Fig. 2701.
Fig. 2702.
V-belting is formed of strips of leather welted together, as shown in [Figs. 2701] and [2702], the latter showing the joint or splice of the belt. The pulleys are V-grooved as shown. The tension of the belt causes it to grip the sides of the groove on the wedge principle, and the belt is flat at the apex of the V so that it shall not bottom in the groove, which would impair its wedging action. This class of belt is largely employed for connecting shafts at an angle, especially in cases where the distance between the shafts is small, in which case it will last much longer than a flat belt.