Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
2001-02-15
2003-04-08
Hess, Douglas (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S834000, C198S835000, C198S861100
Reexamination Certificate
active
06543609
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the conveyor art and, more particularly, to an improved split housing for at least partially covering a drive or idler sprocket in a conveyor system.
BACKGROUND OF THE INVENTION
Today, in many modem. manufacturing facilities, modular conveyor systems are extensively utilized to transport articles to and from various work stations during all stages of production. In recent years, manufacturers using production lines with conveyors as an integral component of the material handling system have realized reasonably significant gains in productivity and resource utilization. As a result, modular conveyor systems have become even more widely implemented and have been adapted to meet an even wider scope of the material handling needs of producers of a multitude of consumer and industrial goods. Therefore, the continual development of improved modular conveyors is necessary in order to keep pace with the demands and expectations of the users of such conveyors.
Conventional conveyor systems employing endless, modular link or roller chain belts are typically driven at one end of an elongated guide structure, such as a rail or the like, by a sprocket coupled to a rotating shaft. The shaft is in turn rotated by a motive device, such as a variable speed electric motor. At the opposite end of the guide structure, an idler sprocket for engaging the belt is coupled to an idler shaft. As should be appreciated, the drive and idler sprockets assist in supporting and guiding the endless belt as it makes the transition from the forward run to the return run, or vice versa, at each respective end of the guide structure.
Of course, both the drive and idler sprockets are subject to wear as a result of the substantially continuous engagement maintained with the conveyor belt. If not kept in check, this wear may affect the overall performance of the conveyor system. For example, a worn sprocket may allow the belt to slip, which creates both timing and efficiency problems. Hence, it is necessary to perform an inspection of the sprocket(s) from time to time to determine whether some form of ameliorative action, such as a repair operation or perhaps even a complete replacement, is required.
While inspection may only require removing the belt to gain visual access to the sprocket, a repair operation or a complete replacement requires removing the sprocket from the corresponding support shaft altogether. In the case where a single unhoused drive or idler sprocket is carried on the shaft, removing the belt and the sprocket is a relatively uncomplicated undertaking. However, in the situation where a plurality of sprockets are gang driven or carried on a single support shaft, removing any of the inner sprockets becomes a time and labor intensive process, since all adjacent outer sprockets and any other corresponding structures (side plates, chain guides/strippers, conveyor frame components or other support structures, etc.) must first be removed. As should be appreciated, removing even a portion of the sprockets significantly increases the time and labor involved. Additionally, the wholesale removal and replacement of multiple sprockets carried on a shaft may create alignment and/or timing problems that must be corrected to ensure efficient operation. Of course, the time and labor required to remedy these problems further exacerbates the situation.
In some conveyor systems, it is also desirable to employ a sprocket housing. An example of a housing arrangement for a sprocket used in a roller chain conveyor system may be found in U.S. Pat. Nos. 5,314,059 and 5,311,983, both the Clopton. As should be appreciated, the use of such a sprocket housing is generally advantageous, since it not only covers and protects the sprocket from external interference, but also provides a guiding function for the belt as it transitions along and is engaged by the sprocket.
Despite generally providing the limited advantages described above, it can easily be appreciated that the use of a housing, such as the one disclosed in the above-referenced patents, serve as yet another obstacle to easily accessing or removing the sprocket. Specifically, since the housing is divided into left and right halves through which the shaft for supporting the sprockets extends, extra effort is required to completely remove the sprocket from the shaft. The amount of effort required is greater in the case where a plurality of sprockets are coaxially mounted, since any adjacent sprockets and/or housings must first be removed. Also, since each portion of the split housing is connected directly to the adjacent guide rail, it is also necessary to remove any fasteners or connectors used to secure the adjacent housings to the guide rails prior to removing the sprocket. This significantly increases the time and expense required for performing even a cursory inspection of a single sprocket to determine whether replacement is warranted.
Another consideration in extending the service life of most driven conveyor belt systems is reducing friction. In the past, many proposals have focused on providing sprocket housings that support the shafts on active bearing elements or, more recently, bearing surfaces formed of materials having enhanced resistance to wear and beneficial tribological characteristics (e.g., ultrahigh molecular weight (UHMW) plastics). Even with the use of such specialized materials, supplying additional lubrication is often desirable to ensure that the drive and/or idler shafts freely rotate relative to the housings and create only a modicum of wear. However, in many conveyor systems, and especially those employed for conveying food products or the like, the operator must be careful in applying the lubricant to avoid potentially creating a contamination hazard. Hence, eliminating the need for external lubrication in conveyor systems where a modular link or roller chain conveyor belt is guided by or through a sprocket housing in making the transition from the forward to the return run in the conveyor system, or vice versa, is desirable.
Accordingly, the foregoing discussion clearly identifies the particular need for an improved manner of housing one of the drive or idler sprockets in a conveyor system. By splitting the housing into first and second portions in a novel manner, it would be possible to mount the first portion independently of any guide rail or structure supporting the second portion. Hence, the second portion could remain attached to a stable structure at all times while the first portion is fully or partially removed. This would permit one performing an inspection to gain full access to the sprocket and adjacent shaft without requiring the removal of the portion attached to the stable support structure, any adjacent sprockets, or other structures. The optional use of a split sprocket would also further enhance the efficiency of the repair or replacement operation, and again without any significant disruption to the overall conveyor system. Likewise, the optional use of an internal lubricant source in the housing would ensure that the desired low friction rotation of the support shaft is achieved without the need for externally applying a lubricant and, in the case where food products are being conveyed, risking contamination. Overall, this combination of features would result in an conveyor system that is a significant improvement over those proposed in the past, especially in terms of maintenance cost and efficiency.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, an apparatus for at least partially covering a sprocket and assisting in guiding a conveyor belt in making a transition from a guide rail over the sprocket (or vice versa) is disclosed. The apparatus comprises a housing split into mating first and second portions. The housing at least partially covers the sprocket and includes a first guide track for guiding the belt along the transition and over the sprocket. As a result of the split in the housing, at least one of the first or second por
Fye Stephen C.
Layne James L.
McDaniel Michael D.
Hess Douglas
King & Schickli PLLC
Span Tech LLC
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