Conveyors: power-driven – Conveying system having plural power-driven conveying sections – With relatively adjustable sections
Reexamination Certificate
1998-10-20
2002-03-26
Olszewski, Robert P. (Department: 2167)
Conveyors: power-driven
Conveying system having plural power-driven conveying sections
With relatively adjustable sections
C198S812000, C198S861100, C198S302000, C198S306000
Reexamination Certificate
active
06360876
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present disclosure is related generally to bulk product conveying machinery and methods including means to permit movement of a conveyor to different working positions or orientations relative to the carrier on which it is mounted. More particularly, the apparatus is related to portable aggregate handling conveyors wherein the conveyor can be telescoped to a more compact configuration than it has when operating to facilitate transporting the conveyor along a highway. In greater particularity, the invention is related to an apparatus including separate conveyors mounted on a single carrier so that they successively convey a load to multiple discharge points to effect the formation of larger stockpiles than is otherwise possible and to reduce the segregation of stored material by size during the stacking process.
In particular, the apparatus according to this specification is related to an endless belt-type conveyor having means for telescopically varying its conveying length either manually or automatically.
2. Description of Related Art
Radial stacking conveyors are known in the art. For example, U.S. Pat. No. 5,515,961 to Murphy and Schmidgall discloses a portable radial stacking conveyor that may be easily folded from its fully extended length of approximately 38.1 m (125 feet) to a transport configuration of slightly more than half the fully extended length. Radial stacking of bulk materials such as aggregate for road construction, grain, or coal enables substantially more material to be stored in a stack than is possible using a conventional, conical stack.
A telescoping, variable length conveyor assembly is disclosed by Thompson in U.S. Pat. No. 4,474,287 issued Oct. 2, 1984, for a variable length conveyor assembly. Thompson's conveyor is intended for use in coal mines to remove coal from a continuous mining machine. Another telescoping mining tool is disclosed in U.S. Pat. No. 4,236,630 issued Dec. 2, 1980 to Sander, et al. for an extensible telescopic coal bunker for subsurface mining. Neither unit is adapted for radial stacking. A similar telescopic belt conveyor is shown in U.S. Pat. No. 4,643,299 issued Feb. 17, 1987, to Calundan for a conveyor that uses a complex serpentine belt path to keep the single belt at the correct tension, regardless of the degree of extension of the discharge end from the feed end.
Another approach is shown by Smith in U.S. Pat. No. 4,523,669 issued Jun. 18, 1985, for a retractable conveyor belt that can include an optional articulated conveyor element on the discharge end of the main, vehicle-mounted conveyor. U.S. Pat. No. 4,624,357 issued Nov. 25, 1986 to Oury et al. for a vehicle-mounted extensible conveyor also describes a portable conveyor that can be extended and retracted in addition to being pivoted both vertically and laterally to discharge material at the desired point. Both of these vehicle-mounted conveyor assemblies are intended for transporting wet concrete from the mixer truck to the pour location. Neither is suited for stacking large piles of aggregate that are needed in the road construction industry.
Several other radial stacking conveyors have been developed by earlier workers in the field. Among those patented are: U.S. Pat. No. 5,390,777 issued Feb. 21, 1995, to Gage for a constant pivot mechanism for variable height radial stacking conveyors; U.S. Pat. No. 4,427,104 issued Jan. 24, 1984 to Reid, Jr. for a radial stacker, and; U.S. Pat. No. 4,245,732 issued Jan. 20, 1981 to Couperus for a compactly foldable radial luffing stacker. None of the radial stackers shown by Gage, Reid, and Couperus disclose extending, telescoping or other means for varying the radius at which material is deposited.
A method and apparatus for accumulating stockpiles of flowable solid material is disclosed by Ryan in U.S. Pat. No. 4,744,459 issued Mar. 17, 1988. Ryan's method includes depositing the material in staggered piles to achieve satisfactory intermixing of the stockpiled materials. The apparatus is intended, however, for use inside buildings and appears to be neither portable nor easily re-locatable.
None of the radial stackers known in the art provide either the maximum storage capacity or the maximum efficiency that could be obtained from a portable radial stacking conveyor. By way of example, a portable telescopic radial stacker that is manufactured by Thor Aggregate Equipment of 839 Westport Crescent, Mississauga, Ontario, L5T 1E7, Canada has a full extension length of about 136 ft. Thor states that its telescopic stacker will stockpile 154% of the material that could be placed using a conventional radial stacker of the same length. The extra material is stacked radially closer to the center, or pivot point, of the arc described by the discharge end of the radial stacking conveyor as it places material for storage.
An article in the July/August, 1998
Aggregates and Roadbuilding Contractor
magazine by Stephen R. Carr identified several limitations inherent in conventional means for radial stacking that may be overcome with telescoping radial stackers. When materials having a distribution of particle sizes are delivered to a stockpile, the particles tend to segregate according to size. Larger particles tend to roll to the bottom of a stack. A conical stack made with evenly mixed material will tend to form with smaller particles being concentrated in the center and top of the stack and larger particles at the bottom and outside of the stack. Those tendencies increase with increasing stack height. The same forces apply to a radial stack with larger particles concentrating at the outer bottom edge of the stockpile. In some instances it is necessary to re-build a stockpile by re-distributing the material with loaders and bulldozers.
When used properly, the telescoping radial stacker will stockpile product without segregating the screened material according to size and deviate from specification. The even distribution of the particles is maintained by stockpiling the material in layers of small stacks instead of one large stack. Not only does the telescoping action minimize size segregation, it also enables the operator to store a substantially larger amount of material in a stockpile of any given radius by filling part of the interior of the stacker arc with material.
In evaluating whether to purchase a conventional stacker, a radial stacker, or a telescopic radial stacker, the costs that must be paid as the result of operating each model should be the considered. Consequences of stockpile size segregation can add considerably to the cost of operating either a radial stacker, which is less expensive than a telescopic radial stacker, or a relatively inexpensive fixed stacker.
An operator supplying aggregate may be required to pay a penalty for delivering non-conforming product. To avoid such penalties, it may be necessary to operate bulldozers, scrapers, dump trucks, loaders, and other machinery for extended periods to reform a segregated stockpile; not only is such machinery expensive to operate, it also compacts, and reduces the value of, the product. A loader may use more operator time, 15 or 20% more fuel, and extra machine wear and tear loading out a compacted aggregate pile compared to a stockpile created by a conveyor.
Other costs of re-blending product can include the reduced availability of machines for revenue-producing tasks, the value of foregone opportunity, and the necessity of purchasing, maintaining, depreciating, and financing additional equipment to replace the equipment engaged in stockpile re-work. The additional work entailed to re-blend aggregate will also increase labor costs. Even if the degree of segregation is not so severe that it must be re-built, more time and more skill will be required if the loader operator must take material from different locations of the pile in order to create, in each truckload, a batch of aggregate that conforms to the applicable specifi
Domnick Bob L.
Kellenberger Rick D.
Nohl Jerry D.
Schmidgall Paul
Jennings Larry M.
Olszewski Robert P.
Ridley Richard
Superior Industries, Inc.
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