Method of fabricating a power transmission belt and apparatus therefor

#This invention relates to a method of fabricating a power transmission belt and an apparatus for carrying out the method. Particularly, the invention relates to such a belt manufacture wherein individual vulcanized belt preforms are machined to have any one of a plurality of different cross-sectional shapes. In the illustrated embodiment, the belt is brought to its desired cross section by cutting the side edges.

#It is conventional to form a plurality of power transmitting belts from a vulcanized sleeve. Such sleeves are conventionally formed by wrapping successive layers of the belt components about a mandrel. Upon completion of the vulcanization of the sleeve, the sleeve is cut lengthwise to define a plurality of separate belt preforms.

#It is conventional to cut the belt elements to the desired trapezoidal shape so as to define individual V-belts without further machining operations. A problem has arisen, however, in connection with such belt manufacture, in that the V-belts often vary from one to the other in length and cross-sectional shape due to machining errors such as may result, for example, from the thermally shrinking material characteristics of the belt. Further, the tensile elements of the belt are often displaced causing shortened useful life of the belt in power transmission use.

#FIG. 1 is a fragmentary, transverse section of a belt sleeve illustrating in broken lines the separation thereof into a plurality of individual belt preforms for further processing in the manufacture of desired V-belts;

#FIG. 2 is a front elevation of an apparatus for fabricating a power transmission V-belt embodying the invention;

#FIG. 3 is a side elevation thereof with portions removed to facilitate illustration of the structure thereof;

#FIG. 1 depicts in cross section a portion of a conventionally formed, layered belt sleeve at 10 from which individual belts can be formed according to the invention. The arrangement of layers exemplifies one known belt construction, however this particular arrangement is not requisite to the performance of the inventive method of forming belts.

#The division of the sleeve 10 into a plurality of square or rectangular belt preforms 12 is indicated by dotted lines 14 in FIG. 1. Each belt preform 12 has an inner, exposed, bias canvas layer 16 and an overlying bias canvas layer 18. The canvas layers 16, 18 are stretchable and have generally the same 90.degree.-155.degree. relationship of crossing warp and weft yarns. The outer portion of each belt preform 12 has an exposed canvas layer 20 and an underlying canvas layer 22, which layers 20, 22 are similar to the aforementioned canvas layers 16, 18.

#The midportion 24 of each preform 12 is made from rubber and has an outer tension section 26 and an inner compression section 28 that is thicker than the tension section 26. High strength tensile cords 30 reside between the sections 28, 30 and are preferably defined by spirally wound polyester fibers with a high resistance to elongation. Short fibers made from, for example, cotton or nylon, may be arranged randomly in generally transverse orientation to the belt length in the compression section 28 of the belt.