Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
2001-08-06
2003-09-09
Hess, Douglas (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S852000, C198S853000
Reexamination Certificate
active
06615979
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to conveyor belts and methods for assembling conveyor belts.
2. Description of Related Art
Conveyor systems are commonly used in various industrial fields for material handling and processing purposes. For instance, conveyor systems are used in food processing systems in which food items are placed on the support surface of a conveyor belt and are processed while being conveyed from one location to another. For instance, the food items may be cooked, baked, frozen, washed, or subject to other processing steps while being conveyed on the conveyor belt. Various different types of conveyor belts have been used in such applications such as wire mesh conveyor belts but various hybrid belts have become especially popular in such food processing systems and other applications where a flat support surface is desirable to provide greater support for the objects being conveyed. Moreover, such conveyor systems are used in a helical accumulator such as that disclosed in U.S. Pat. No. 5,070,999 to Layne et al. which allows storage of large number of items in the conveyor system.
In such hybrid conveyor belts, a plurality of elongated rods are interconnected with one another via plurality of links such as drive links that may be mounted to the end of the elongated rods. The elongated rods and the drive links are typically made of metal to ensure sufficiently strong interconnection between the elongated rods. Moreover, the drive links are typically welded to the ends of the elongated rods to maintain the positioning of the elongated rods as the conveyor belt is driven through the conveyor system.
The hybrid conveyor belts also include a plurality of overlay elements which are mounted to the elongated rods of the conveyor belt, the plurality of overlay elements providing the conveying surface. The overlay elements are generally made of a non-metallic material such as plastic, nylon, or other composite materials. The use of such overlay elements has become popular especially in food processing applications because the conveyance surfaces provided by such overlay elements are easy to clean and can be treated to resist growth of pathogens such as germs, fungus, viruses and bacteria. In such a manner, hybrid conveyor belts can aid in the reduction of food borne ailments by improving sanitation.
The overlay elements of a hybrid conveyor belt are typically mounted to the elongated rods in various ways. One common method is by providing the overlay elements with a clip feature which directly clip on to the elongated rods thereby securing the overlay elements thereon. For instance, U.S. Pat. Nos. 3,416,645 to Jones, No. 3,799,328 to Harvey, and No. 4,582,193 to Larsson disclose various hybrid conveyor belts with overlay elements having a clip with vertical openings that allow vertical insertion of the overlay elements on to the elongated rods. However, the present inventors have found limitations in such prior art hybrid conveyor belts as discussed in further detail below that limits the applications in which such conveyor belts can be used.
In other hybrid conveyor belt configurations, the overlay elements are not provided with any vertical openings, but instead are merely provided with transverse openings that slidably receive an elongated rod. In such hybrid conveyor belts, the drive links must be properly mounted to the ends of the elongated rods to ensure that the overlay element does not slide off the elongated rods. However, because the overlay elements are made of plastic or other composite materials and melt when exposed to very high temperatures, metal drive links cannot be readily used since they cannot be welded, or otherwise mounted to the elongated rods. Consequently, drive links made of plastic or other composite material must also be used.
In this regard, U.S. Pat. No. 5,031,757 to Draebel et al. discloses this type of hybrid conveyor belt in which the overlay elements are slid on to the elongated rods. To mount the drive links to the end of the elongated rods, Draebel et al. discloses that the drive links includes an opening for receiving a locking tab that engages a notch provided on the ends of the elongated rod when the locking tab is inserted into the opening of the drive link. In this manner, the overlay elements are prevented from sliding off the elongated rods and the drive links are mounted to the ends of the elongated rods. However, the present inventors have found that there are disadvantages to such prior art hybrid conveyor belts as described hereinbelow.
SUMMARY OF THE INVENTION
More specifically, with respect to the hybrid conveyor belts where the overlay elements are clipped to the elongated rods, the present inventors found that these overlay elements often become detached from the elongated rods. For instance, when such overlay elements are used to convey food items which are sticky and adhere to the conveying surface of the overlay elements, the overlay elements tended to detach from the elongated rods together with the food item when the food item is removed from the conveyor belt. In other applications such as when food items are frozen on the conveyor belt, the food items also tended to adhere to the surface of the conveying surface of the overlay element so that upon its removal, the overlay element also became detached from the elongated rod. Therefore, such hybrid conveyor belts having overlay elements which are mounted to the elongated rods using clips as described in the prior art have been found to be inadequate in many applications where the item to be conveyed adheres to the surface of the overlay element.
Moreover, with respect to hybrid conveyor belts where the overlay elements are slid on to the elongated rods and mounted at the ends, the present inventors have found that in certain applications, the mechanism that mounts the drive link to the end of the elongated rods pose sanitation issues. In particular, the securing mechanism such as the locking tab disclosed in Draebel et al. provide crevices and interfacing joints which are very difficult to clean. Thus, these crevices and joints provide an environment in which bacteria, mold, and fungus can readily grow and viruses can be conveyed and transferred, thus resulting in unsanitary conditions for food processing applications.
Moreover, in the prior art conveyor belts such as that disclosed in Draebel et al., the drive links cannot be readily mounted to the ends of the elongated rods without such locking tabs or similar locking mechanisms. As previously described, the drive links cannot be mounted to the end of the elongated rods using the conventional methods such as welding or other high temperature processes since the overlay element which is slidably received on to the elongated rod is typically made of a non-metallic material such as plastic, nylon, or other composite materials which will melt or otherwise be damaged by application of such high temperatures. Correspondingly, this also requires the use of non-metallic drive links with locking mechanisms with the associated disadvantages noted above since the integral locking mechanisms cannot be economically incorporated into such metal drive links.
Therefore, there exists an unfulfilled need for a conveyor belt with overlay elements in which the overlay elements are not easily removed from the conveyor belt. There also exists an unfulfilled need for such a conveyor belt with mechanisms for resisting removal of the overlay elements. In addition, there also exists an unfulfilled need for such a conveyor belt which will allow high temperature processing at the ends of the elongated rods, even when the overlay elements are made of a non-metallic material. Lastly, there also exists an unfulfilled need for such a conveyor belt in which facilitates cleaning so as to facilitate maintenance of sanitary conditions.
In view of the foregoing, one advantage of the present invention is in providing a conveyor belt with overlay elements in which overlay elements are not easi
Etherington Michael
Henderson Joy B.
Ashworth Bros. Inc.
Brackett, Jr. Tim L.
Hess Douglas
Nixon & Peabody LLP
Song Daniel S.
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