Conveyors: power-driven – Conveyor section – Reciprocating conveying surface
Reexamination Certificate
1998-04-07
2001-07-10
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor section
Reciprocating conveying surface
Reexamination Certificate
active
06257396
ABSTRACT:
BACKGROUND OF THE INVENTION
1. FIELD
The subject invention is in the field of conveyors, specifically conveyors for use with bulk materials such as fertilizer, sawdust and grains and generally known as particulate materials. More specifically, it is in the field of particulate material conveyors usable on conveyances such as trucks and trailers and, still more specifically, such conveyors in which the material is supported on a floor comprised of longitudinal members called slats and the material is moved by longitudinal oscillation of groups of slats.
2. PRIOR ART
The U.S. patents listed below are a selection of prior art in this still more specific field.
4,679,686
7/1987
Foster
5,088,595
2/1992
Hallstrom, Jr.
4,749,075
6/1988
Foster
5,238,360
8/1993
Foster
4,785,929
11/1988
Foster
5,267,641
12/1993
Hallstrom, Jr.
4,856,645
8/1989
Hallstrom,
5,323,894
6/1994
Quaeck
Jr.
4,858,748
8/1989
Foster
5,325,957
7/1994
Wilkens
4,896,761
1/1990
Foster
5,335,778
8/1994
Wilkens
4,940,132
7/1990
Foster
5,346,056
9/1994
Quaeck
4,984,679
1/1991
Foster
5,560,472
10/1996
Gist
5,064,052
11/1991
Foster
The prior art conveyors suffer from wear and failure because they are relatively complex and incorporate various kinds of seals to prevent particulate material from migrating through the floor between the slats. The wear, failure and complexity all add to the costs of using these conveyors. For example, the Foster '686, '075 and '929 conveyors all use pluralities of bearings to support the slats, as many as 1300 in an average trailer installation. Installation of these bearings is done by hand and requires considerable man-hours. For another example, the seal strips used between slats in the conveyors of Foster '132, '679 and '052 are known to require replacement which is costly because of the repair costs and the downtime required for the repairs. Such seals also introduce an extra component of friction into the operation of the conveyors, further adding to the cost of operation.
In Hallstrom, Jr., '645 and '595, there are no seals between the edges of the slats and particles collect in channels below the slats. Seals are used to prevent these particles from migrating into the bearings supporting the slats. The accumulation of these particles can be troublesome.
Quaeck (the inventor of the subject invention), in his patents '894 and '056, shows reciprocating conveyors with no seals between the slats and having a liquid tight base structure. Particles which fall between the slats accumulate in grooves, do no harm and can be flushed out during cleaning of the conveyor. The expense of a liquid tight base is rarely justifiable. Also, in Quaeck '894 the beams on which the bearing strips and slats of the reciprocating floor are extrusions with each extrusion comprising multiple beams or beam parts. This construction involves so-called “dead weight” of material between the beams and beam parts. This extra weight increases the costs of manufacturing and using the floor.
In the “walking floors” of Gist '472, the slats have flanges at each of their edges and the flanges serve as both bearings and seals, called bearing/seals. This construction requires use of a guide rail for each slat, with associated fasteners and results in relatively low bearing areas. Since some particulate matter is abrasive, the flanges and/or bearing material tend to wear and the wear tends to be uneven, further decreasing effective bearing area and sealing capability. The flanges (called ears in Gist) are more likely to wear than the high molecular weight bearing material and repair might require replacement of the slats having worn flanges.
In view of the prior art, the primary objective of the subject invention is to provide a reciprocating conveyor which has no seals but is impervious to particulate matter. A second important objective is that the conveyor be mechanically and structurally simple compared to related prior art. Related objectives are that (1) the floor be simple to install with all fastening done from above floor level and (2) the number of components (parts count) be relatively low. Another objective is that the structure involve a minimum of dead weight.
SUMMARY OF THE INVENTION
The subject invention is a reciprocating conveyor for use in various conveyances including trucks and trailers for supporting and unloading loads of particulate materials such as grains, sawdust, fertilizer and the like. The conveyor comprises a plurality of slats installed edge to edge lengthwise of the conveyor. It is well known in the art that loads are moved on such conveyors by reciprocating the slats in a particular sequence. When the slats are moved simultaneously in one direction the load moves in that direction. The slats are then retracted in groups, such as three groups, to the starting position and the load does not move in the retraction direction.
The various conveyances in which reciprocating conveyors are installed have what is termed a bed on which the conveyor is supported and the bed comprises a plurality of cross beams extending the width of the conveyor, installed perpendicular to the length of the conveyance and conveyor and preferably evenly spaced over the length. The conveyor comprises a plurality of longitudinal beams, a plurality of bearing strips, a plurality of slats and fasteners (or welding) for attaching the longitudinal beams to the cross beams. The longitudinal beams each extend the length of the conveyor but need not be all one piece. They are evenly spaced across the cross beams with the bottoms of the longitudinal beams down and in contact with the crossbeams. They can be fastened to the crossbeams by welding if material selections permit or by threaded fasteners installed in holes in the bottoms of the beams and threaded into threaded holes in the crossbeams. There may be fastening at each intersection of crossbeam and longitudinal beam but fewer fastenings may be used if design conditions allow. The longitudinal beams are parallel to each other, and flanged at their upper edges, the flanges being parallel to the cross beam upper surfaces, i.e. horizontal. The longitudinal beams are configured to provide access of fastening tools to the fasteners if fasteners are used to fasten the longitudinal beams to the cross beams.
A bearing strip is installed on each longitudinal beam. These strips are preferably plastic and at least as wide as the distance between the outer edges of the flanges of the longitudinal beams. The upper surface of each bearing strip has a longitudinal groove along its center. Flanged, longitudinal ribs on the bottom surface of each bearing strip engage the flanges on a longitudinal beam to prevent the bearing strips from lifting off of the longitudinal beams. In an alternate embodiment the bearing strips extend around the outer edges of the flanges of the longitudinal beams. The bearing strips are moved longitudinally onto the longitudinal beams.
The slats reciprocate longitudinally, supported on the bearing strips. Flanged ribs on the lower surfaces of the slats engage the edges of the bearing strips or flanges of the channel beams, depending on the embodiment of the invention, to prevent the slats from lifting off of the bearing strips. In one embodiment of the invention there are flanges extending downward from the lower surface of each slat at the edges of the slat. The width of the slats is such that these flanges fit into the grooves in the upper surfaces of the bearing strips and engagement of the ribs with the sides of the grooves provides lateral restraint of the slats. In an alternate embodiment there are no flanges at the edges of the slats and lateral restraint of the slats is provided by engagement of the flanged ribs on the lower side of the slats with edges of the bearing strips.
Mechanism well known in the art is used to move the slats in unison in one direction to move a load in that direction and to move the slats in groups in the other direction to reset them for another move in unison.
The invention is
Bidwell James R.
Jenny Robert W.
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