Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Separating means
Reexamination Certificate
1999-02-02
2001-02-06
Nguyen, Tuan N. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Separating means
C209S668000, C209S919000
Reexamination Certificate
active
06182832
ABSTRACT:
BACKGROUND
The invention relates to processing food products generally and, more particularly, to apparatus for grading and sorting shellfish, such as shrimp, by size.
In the food processing industry, particularly the shrimp processing industry, a premium is paid for larger shrimp. Consequently, it is common practice to sort shrimp according to size. Various grading devices are used to sort shrimp. One type is a rolling conveyor grader, which includes a series of parallel rollers rotatably connected at each end to the links of an endless chain. A motor and gears drive the chain and the rotating rollers along a path including an upper grading path and a lower return path. Grading is achieved by adjusting the spacing between the rollers on the grading path from narrow where the product enters to wide at the other end. The smaller shrimp drop between the narrow gaps nearer the entry end, with increasingly larger shrimp dropping off further along the grading path as the gaps increase in width. Dropping product is typically collected below by one or more conveyor belts.
These rolling conveyor graders have some shortcomings. For example, in some graders, the grading sizes are fixed by the manufacturer and cannot be easily adjusted by the user to adapt to a change in the range of product sizes. Adjustable graders are available, but they typically require a separate adjustment for each size, or grade, and the number of grades is limited to the number of adjustments provided.
Thus, there is a need for an adjustable grader that minimizes the number of adjustments a user must make, while providing a large number of grades.
SUMMARY
These needs and others are provided by an improved grading apparatus having features of the invention. The improvement includes a single adjustment rail at each side of the roller conveyor cooperative with each chain. The adjustment rail has a bottom cam surface along which the wheels of adjustment levers roll. A tensioning bar is attached to the adjustment rail to maintain the rigidity of the rail. The levers are pivotally attached to the chain at each roller position. Rail adjusters at each end of the adjustment rail allow the user to raise or lower the ends of the rails in tandem. By adjusting the two ends of the rails, the spacing between the cam surface and the chain can be controlled along the grading path. With the cam surface close to the chain, the adjustment levers cause the chain by lever action to kink, which closes the gap between consecutive rollers. Because the adjustment is at the two ends of the rail, the spacing can be adjusted to provide a linearly increasing distance between the chain and the cam surface for a continuously increasing spacing between consecutive rollers along the grading path. In this way, two adjustments can be used to adjust the grading range of the apparatus.
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Laitram Machinery, Inc., Product Brochure, “Model LG 30 Grader,” 1997.
Laitram Machinery, Inc., Product Brochure, “Model LG 70 Grader,” 1997.
Fournet Francis
Grisbaum Daniel W.
Ledet Brent A.
Mauduit Loren M.
Sirgo Scott J.
Cronvich James T.
Nguyen Tuan N.
The Laitram Corporate
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