Belts 4, and more particularly conveyor belts, are typically fabricated from multiple layers 8,6, as shown in FIG. 1. In most belts, the different main layers 6 of rubber or other plastic material are interleaved with reinforcing layers 8 of fabric or the like to form a laminate structure. Because it is desirable for the reinforcing layers 8 to be bonded to the main layers 6 very tightly to help promote maximum strength, the main layers 6 are bonded to the reinforcing layers 8 through special bonding processes typically tightly controlled by the belt's manufacturer. The belts 4 are typically manufactured in long strips which are spliced together in one or more locations to form a continuous loop. Due to the stresses imposed on the conveyor belts, it is important that the splice be as high a quality as possible so as to prevent, or at least delay, belt failure at the splice.
Over time, a number of methods have been employed to splice belt ends together. The simplest method is the butt splice where the opposing ends of the belt are cut and then bonded together, such as by glue or stapling. Such butt splices are weak. Stronger splices are achieved when there is some sort of overlapping of the two belt ends, such as when the top half of one end and the bottom half of the other end are removed and the complementary portions of the ends are overlapped and bonded together by gluing, etc., and thereafter vulcanizing with presses having heated platens. For some applications, it is desirable to form stepped splices having staggered overlapping levels, as shown in FIG. 1. In addition, the belt material of the complementary opposing ends may be formed into an interleaved finger arrangement. It is believed that strong joints are formed when complementary portions of a main layer 6 from of the opposing ends of the joint are bonded together without an intervening reinforcing layer 8, as shown in FIG. 1. Further, it is desirable for the reinforcing layers 8 of the respective ends to be both unseparated from their adjoining main layers 6 and undamaged. Whatever the splice arrangement, the opposing belt ends of the splice are typically cut so as to mirror each other.
In order to form overlapping splice joints, it is necessary to remove a portion of the belt material from the respective belt ends. Typically, this process is a manual process in which two of the layers are separated by stripping one from the other for some distance along the belt, then cutting off the material above or below the separation. This manual stripping process typically involves the use of cutting blades, pliers, buffing machines, and the like, and is time consuming. Due to the various levels of cohesion, adhesion, and localized stresses, this manual stripping almost invariably produces a rough surface having numerous pits and leftover tags of material, requiring subsequent buffing or sanding to create a smoother surface suitable for splicing. In addition, the manual process frequently damages the "skim layer", the portion of the main layer material closest to the reinforcing layer 8 which provides the adhesion between the main layer 6 and the reinforcing layer 8. Further, the manual process frequently damages the material of the reinforcing layer 8 itself.
Alternatively, belt splitting machines are available. A belt splitting machine is designed to split a layer of the belt (typically a main layer 6), rather than separating or stripping one layer from another. A typical example of an available belt splitting machine is the model Type 95 from Muller & Kurth Offenbach A. M. of Germany. This machine uses a pair of continuously driven pinch rollers to force the belt into stationary cutting blade. The cutting blade impinges upon the side of the belt at a given vertical height and splits the belt from one side to the other as the belt is fed into it. Due to the mechanics involved, the machine is rather cumbersome and can only be used to split the belt up to a rather limited length, such as five inches. The machine is unsuited to making multiple staggered splits at different levels of the same belt end.
In light of the above, there remains a need for a belt splitter which can split a belt for a variable length as the user demands and that can split the belt without damaging the reinforcing layers. It is desirable, but not required, for such a machine to be able to split the belt both square, i.e. perpendicular with respect to the belt length, and on a bias, i.e. diagonally with respect to the belt length. It is further desirable, but not required, for such a belt splitter to be suitable for making staggered length splits at different depths of the same belt end.
USPTO Backgrounds
USPTO Backgrounds