Conveyors: power-driven – Conveyor section – Unit load conveying surface means moved about an endless or...
Reexamination Certificate
2000-02-28
2001-11-20
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor section
Unit load conveying surface means moved about an endless or...
Reexamination Certificate
active
06318543
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a product transport system and, in particular, to a system for transporting product support trays along a non-linear path. The invention has been developed in the context of a food processing installation and the invention is hereinafter described in that context. However, it will be understood that the invention does have broader application, for example to the transportation of industrial products through a processing zone.
BACKGROUND OF THE INVENTION
In the most relevant of all known food processing installations, dough deposits are loaded onto flat or compartmented product support trays and are conveyed serially through an oven chamber. The trays would normally also be conveyed through at least one further chamber, for example a cooling chamber, a refrigerating chamber or a tray washing chamber. In moving through the oven chamber (and, similarly, through other chambers) the trays are conveyed in a manner such that they make a succession of forward-and-return horizontal passes along the length of the chamber. The trays are supported by individual carriers, from which they may be removed, and each carrier is connected to and extends between two spaced-apart parallel conveyor chains which are driven by a common drive system to move through the chamber. The respective conveyor chains are guided by sprockets to make the changes in direction between the forward-and-return horizontal passes and, also, at opposite ends of the chamber to direct the conveyor chains in vertical directions between the upper and lower levels of the chamber.
The tray carriers extend across substantially the full width of the chamber and they are pivotably connected at their ends (adjacent side walls of the chamber) to the conveyor chains. The pivotable connection permits each tray carrier to maintain a horizontal disposition when being conveyed around the sprockets and when being conveyed (upwardly or downwardly) in a vertical direction.
Horizontal rails are provided at each side of the chamber and they are used to maintain the tray carriers in a stable, horizontal disposition when the carriers are moved along the horizontal passes within the chamber. However, the known food processing installation does not make any provision for maintaining the trays in a horizontal disposition other than when the tray carriers are supported by the horizontal rails.
A significant problem that has been found to exist in the known food processing installations is that, with any eccentric loading or disturbance of any of the trays, the affected trays and tray carriers are caused to rock when being transported around sprockets or in a vertical direction. This problem is exacerbated with large sized trays and/or when relatively large dough deposits are carried by the trays.
When rocking of a tray becomes sufficiently pronounced, the associated tray carriers that are about to move into a horizontal pass may momentarily be tilted to such an extent that they will be misdirected below the intended horizontal support rails. When this happens, crashing may (and has been known to) occur between moving trays and fixed structures within the chamber.
An attempt has been made to alleviate the above stated problem by connecting each pair of tray carriers with a relatively heavy transversely extending metal bar. The use of these bars has to a limited extend been helpful in minimizing rocking of the trays, but the use of the bars has created further problems. Given the fact that, in a typical installation, something in the order of 200 trays may be conveyed through and from the oven chamber (and other associated chambers) in the installation, the bars add significantly to the thermal mass of the system, to the drive power requirements and to cooling requirements if the trays are to be conveyed through a cooling chamber following movement through the oven chamber.
SUMMARY OF THE INVENTION
The present invention seeks to provide a system which, in a particular embodiment, facilitates stable conveyance of product support trays through a chamber in circumstances where the direction of movement of the trays is required to be changed whilst moving through the chamber.
As indicated previously, the invention has application to a product transport system of a type that is contained within a chamber (for example, an oven chamber), and in this context the invention may be defined more particularly as follows:
A product transport system which comprises a chamber, a pair of parallel, spaced-apart conveyor chains located within the chamber and arranged to convey a plurality of transversely extending product support trays through the chamber, a pair of transversely spaced carriers arranged to carry respective ones of the trays, chain sprockets located within the chamber in alignment with the respective conveyor chains and arranged to direct the respective conveyor chains through changes in direction (including through forward-and-return horizontal passes) within the chamber, rotatable guide members positioned laterally adjacent to but out of alignment with respective ones of the chain sprockets, and means for driving each guide member in synchronism with an adjacent one of the chain sprockets. Each carrier has a first spigot that is connected to an associated one of the conveyor chains and a second spigot that is positioned and arranged to engage with a said guide member when a portion of the conveyor chain to which the first spigot is connected is being directed around an adjacent one of the chain sprockets.
In the above defined transport systems a two-point support is provided for each of the carriers when it is conveyed through changes in direction. This obviates the pivoting problem that is inherent in single-pivotal support. Also, it facilitates the maintenance of a constant (usually horizontal) disposition of each carrier as it is conveyed through changes in direction.
PREFERRED FEATURES OF THE INVENTION
Various arrangements may be employed for maintaining each of the carriers in a horizontal disposition when it is being conveyed in a horizontal direction. However, it is preferred that horizontally extending rails be provided for supporting horizontal passes of the conveyor chain and, at the same time, for supporting the second spigot of each carrier.
In the embodiment of the invention that incorporates product support trays, the trays preferably are removably mounted to support frames which, in turn, are removably mounted to the carriers.
The invention will be more fully understood from the following description of a preferred embodiment of a product transport system that is embodied in a food processing oven. The description is provided with reference to the accompanying drawings.
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patent: 1905224 (1933-04-01), Hass et al.
patent: 2493857 (1950-10-01), Cargill
patent: 3150765 (1964-09-01), Ellis
patent: 3587829 (1971-06-01), Sorensen
patent: 4346803 (1982-08-01), Haessler et al.
patent: 4378873 (1983-04-01), Cloudy
patent: 4421227 (1983-12-01), Kornylak
patent: 6010016 (2000-01-01), Siegal
patent: 8071839 (1984-10-01), None
Commander Land & Air Investments Pty Limited
Ladas & Parry
Valenza Joseph E.
LandOfFree
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