Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1999-12-09
2001-06-26
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S817000
Reexamination Certificate
active
06250457
ABSTRACT:
BACKGROUND OF THE INVENTION
Chains are well known in the art and are normally classified by use. Roller chains are used, for example, to drive a sprocket. In this type of chain, tension forces are applied along the length of the chain. Normally no forces are applied perpendicular to the path of travel of the chain.
Another type of chain is an engineering class steel chain. While roller chain primarily meet drive chain needs, engineering steel chains are often used where designed for difficult conveying applications. The present invention is directed to an engineering class steel chain which is used to convey, for examples, truck or automobile components in a factory operation. The vehicles are placed on custom designed pallets which are normally carried along the upper surface of the engineering steel conveyor chain. The weight of the vehicles places a downward compression load on the upper surface of the conveyor chain.
The conveyor chains include side bars and rotating steel rollers which support the pallets. Normally pins extend between the side bars of the conveyor chain and rollers are mounted for rotation on the bushing pin. It has been found that as the chains wear, the friction and loading of the chains tend to restrict rotation of the rollers. To alleviate this problem, it is common to lubricate the rollers with various types of lubricating oils or greases. The wear, maintenance and cleaning of prior art chains create problems for the users. In addition to the inherent problems with the use of solvents, the overall waste problems and wear problems are significant.
The present invention is directed to an improved engineered steel chain, for carrying loads perpendicular to the path of chain movement.
SUMMARY OF THE INVENTION
The present invention is directed to an improved conveyor chain and more specifically to an improved engineering steel chain. The improved conveyor chain is suitable for carrying a downward load while moving along a horizontal path. The improved conveyor chain includes a plurality of inner connected link assemblies. The link assemblies include spaced parallel metal side bars and a plurality of roller assemblies which are mounted for rotation between the metal side bars. Each of the roller assemblies includes an outer metal roller defining an outer support surface and an inner opening. A cylindrical plastic bushing is positioned within the inner opening of each of the outer metal rollers. The plastic bushing has a compressive strength of between 20,000 and 25,000 psi. The plastic bushing also defines a central opening for receiving a pin bushing extending between the metal side bars. In a preferred embodiment, the plastic bushing is constructed of a glass reinforced nylon which includes a polytetrafluoroethylene. Preferably, the plastic bushing also includes silicon.
The outer metal roller has opposed ends and a predetermined width. The plastic bushing has a width greater than the predetermined width of the roller thereby defining an upset or protuberance at each end of the bushing. The upset restricts movement of the metal roller against the side bars.
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patent: 2275244 (1942-03-01), Bee et al.
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patent: 2816453 (1957-12-01), Frank et al.
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patent: 730408 (1966-03-01), None
Karen Auguston Field, Powered Conveyors For Heavy Duty Loads, from Modern Materials Handling, Equipment Report, Aug. 1997, pp. 37-40.
Material regarding Glass Reinforced Nylon From ERIKS/Midwest of Aurora, Illinois, undated.
Riedel James F.
Spurck Fredric C.
Emch, Schaffer, Schaub & Porcello & Co., L.P.A.
Valenza Joseph E.
Webster Industries, Inc.
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