Conveyors: power-driven – Conveyor section – Having means to enhance the friction or adherence between...
Reexamination Certificate
2000-06-22
2003-06-03
Tran, Khoi H. (Department: 3651)
Conveyors: power-driven
Conveyor section
Having means to enhance the friction or adherence between...
C198S690100, C198S820000, C198S821000, C198S844100, C198S846000
Reexamination Certificate
active
06571935
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to flexible conveyor belts. More particularly, the present invention relates to a rubber conveyor belt having an integrally formed sidewall with fabric reinforcement.
2. State of the Art
Conveyor belts of various designs have been used for centuries to convey materials from one location to another. One of the oldest types of conveyor is the trough conveyor, wherein a flexible conveyor belt is disposed over rollers or supports which are formed into a generally U-shaped trough. This type of conveyor has the disadvantage that it cannot be used to transport material up an incline having an angle that is greater than the dynamic angle of repose of the material which is being transported. Because they flex in multiple dimensions, trough conveyor belts cannot easily be provided with cleats or other devices for assisting in transporting the material up steep inclines.
To overcome this problem, conveyor belts have been developed having a flat base belt, upstanding longitudinal sidewalls, and transverse cleats or other protrusions which extend from the surface of the base belt and provide individual compartments in which the material may be held and lifted for transport up relatively steep inclines. Other belt designs have been developed, including belts with longitudinal sidewalls and a grid pattern of protruding nubs for use with certain types of materials, and belts with attached buckets attached for containing and lifting materials. These newer belt designs allow much steeper incline angles, actually allowing completely vertical conveyance of some materials.
To be useful, conveyor belts must be both flexible and durable. To this end, modern conveyor belts are typically made of synthetic rubber materials, with fabric reinforcement. However, the newer, more complicated belt designs mentioned above present several challenges. Belts having sidewalls are frequently constructed using separately cured components (a base belt and two sidewalls) which are bonded together with adhesives using both “cold” and “hot” processes. While this approach is simple, it is not durable. The repetitive flexing action of belts traveling along a conveyor and around turn disks, drive pulleys, etc., commonly results in the failure of bonded belt sidewalls, wherein the sidewalls tend to delaminate from the planar base belt after relatively brief use. This is because the bond strength from adhesives is usually less than 40% of the strength of the cured rubber material itself. Thus, belts with adhesive bonded sidewalls tend to have a relatively short useful life.
It will be appreciated that rubber parts, whether reinforced or unreinforced, are strongest when an entire piece is molded and cured monolithically. Accordingly, the inventors have developed a method of constructing a flexible rubber belt having sidewalls that are integrally formed and cured with the base belt. With this construction, the problem of delamination of the side wall from the base belt has been eliminated. However, there are some additional problems. First, the exposed top edges of belt sidewalls, whether formed monolithically with the base belt or not, tend to get damaged due to operating stresses, and by contact with guide rollers, sliding surfaces, turn disks, etc. These problems are most pronounced when the sidewalls are relatively large—e.g. 6″ tall or more. To address these problems, it would be desirable to include fabric reinforcement in monolithically formed sidewall belts. However, heretofore, there has not been a way to form and cure a belt sidewall monolithically with the base belt and include fabric reinforcement in the sidewall. This is particularly true where the sidewalls are relatively large.
SUMMARY OF THE INVENTION
The invention generally comprises a conveyor belt, having an elongate, substantially planar base belt, at least one longitudinal sidewall extending upwardly from a top face of the base belt along a length thereof, and fabric reinforcement disposed within the sidewall. The sidewall is integrally formed of the material of the base belt, and is simultaneously cured therewith. The invention thus provides a flexible conveyor belt with monolithically formed and cured sidewalls having fabric reinforcement. The sidewalls are thus more durable than prior belt sidewalls, and do not present the likelihood of delamination from the base belt which bonded sidewalls present. The belt may include cleats between the sidewalls, such as transverse paddles or upstanding nubs, to assist in conveying material on steep inclines.
Other advantages and features of the present invention will be apparent to those skilled in the art, based on the following description, taken in combination with the accompanying drawings.
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Campbell Colin D.
Schmidt Mark
Cambelt International Corporation
Thorpe North & Western, LLP.
Tran Khoi H.
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