This invention relates to a spliced conveyer belt assembly and particularly to an endless belt comprising an elongated belt having a laterally extending joint connecting the ends together. Such belts have applications in various feed mechanisms including gravimetric feeders. Gravimetric feeders are used in a wide variety of applications where it is desired to continually measure the respective weights of one or more materials being supplied to an industrial process on one or more belts. There are a large number of possible applications for such belts. One of many such applications is to feed crushed fuel and sorbent to a combustor in a circulating fluidized bed steam generator. In such an application belt scales are disposed along the belt at spaced intervals along the belt. The apparatus makes possible the measurement and the comparison of the respective weights to enable the control of the supply of gravimetric quantities of sorbent and fuel to the boiler.
Conveyor belts used in gravimetric feeders have particularly rigid standards. These standards include requirements for uniformity througout the axial extent of the belt. This is of great concern since any non-uniformity would result in inconsistent measurement of the same mass at different axial parts of the belt. Another requirement, which is of paramount concern, is that the belt must be extremely flexible so that in the weighing zone near a belt scale the proper impact of weight can be fully transmitted through the belt.
For many years following the introduction of gravimetric feeders in the 1950's, endless belts (those having no mechanical splice of the ends) were primarily used because of the importance of maintaining the required accuracy The major concern with belts having a mechanical splice was the potential for damage to the weighing platform and the potential for inaccuracies because of the non-homogeneous characteristic of the belt as the result of the splice. Because the installation of endless belts on the conveyor apparatus is much more difficult and costly than belts having a splice connecting the ends, most feeder operators have used spliced belts. There are a variety of spliced belts currently on the market.
One known type of spliced belt has a so called hinged joint. The design of such a joint may be visualized by comparison to a conventional hinge such as a common hinge used to hang a door on a door frame or a piano hinge used to mount the cover that covers the keys of a piano. Both the hinged joint and the hinge have a plurality of coaxial, axially abutting, cylindrical elements. In a common hinge the cylindrical elements that are coaxial and axially abutting are alternately connected to (1) the door frame and the door or (2) the cover for the keys and the body of the piano. In a hinged joint for a spliced belt a twisted multistrand aircraft cable extends through a plurality of cylindrical elements. Successive cylindrical elements are alternately fixed to a first end of the belt and a second end of the belt. Accordingly, the first end of the belt can pivot about the common axis of the cable with respect to the second end of the belt. Further details of one such hinged joint is shown in U.S. Pat. No. 5,234,101 issued to Herold on Aug. 10, 1993.
Even spliced belts are difficult to install. The difficulties include (1) the difficulty of moving the bulky and heavy belt into an area that is not easily accessible and (2) the difficulty of making the physical connection between the ends of the belt. A typical belt weighs about 85 to 100 pounds and is 16 feet long. Other belts may be much longer and proportionally heavier. The apparatus within which the belt is mounted typically has first and second housings in which rollers are disposed. Often the access to the rollers over which (or around which) the belt is installed is severely limited. Accordingly, it is difficult to position the relatively heavy and cumbersome belt on the rollers. In some cases C-clamps are tightly secured on the end of the belt and ropes passed through the C-clamps so that a person installing the belt can pull on the rope to position the belt for installation. This process is not desirable (1) because it typically requires two people to position the belt and secure the ends of the belt together and (2) because the C-clamp may damage the belt because of the high compression forces that may be concentrated on a small area.
The difficulty in connecting the ends of the belt is related, in part, to the difficulty of installing the aircraft cable within the cylindrical elements. Much of this problem develops because it is very difficult to precisely align the cylindrical sections and this results in a passageway having a plurality of steps or shoulders along the axial extent of the passageway through which the multistrand cable must be inserted. This is compounded by the cable not being perfectly straight, not being rigid, and sometimes having individual strands that may project from the rest of the twisted strands. The lack of rigidity, the presence of shoulders in the passageway for the cable and the projection of individual cable strands will be understood to be particularly significant because the typical belt has a width of 33 or more inches.
It is an object of the present invention to provide apparatus that facilitates the insertion of an aircraft cable into the cylindrical elements of a conveyor belt hinge joint.
It is another object of the invention is to provide a belt apparatus that is easier to install.
Another object of the invention is to provide apparatus that facilitates installation by only one worker.
Yet another object of the invention is to provide apparatus that will allow a worker to grip the end of the belt in a positive firm manner that will not damage the belt.
Still another object of the invention is provide apparatus that is easy to construct.