Patent Publication Number: US-RE37121-E

Title: Reciprocating slat conveyors

Description:
The present invention relates, in a general sense, to walking floors  reciprocating slat conveyors for use in mobile, as well as stationary, applications and more particulary to improvements in the sealing of such floors  conveyors against arbitrary and inadvertent loss of material stored upon and moved by such floors  conveyors. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The storage and transportation of particulate materials such as grains, sawdust, wood chips, feeds, similar powdery materials, and even such materials having a liquid component, has been a matter of industry concern for several years. Materials such as those identified above will be referred to hereinafter simply as particulate materials. 
     Hoppers, bins and silos are all capable of storage of such materials, but are of limited use in transportation. Moreover, costs incident to the construction of such vessels, which is labor intensive, approaches the prohibitive. 
     Walking floors, sometimes referred to as reciprocatingReciprocating slat conveyors, have been found useful in the loading and unloading of more readily available rectangular enclosures wherein difficulty is encountered in using front end loaders, or other similar devices, to accomplish the task of moving particulate material into and out of a storage or transportation facility. 
     Such systems typically comprise a series of floor members, sometimes referred to as slats, which are disposed in side by side relation to form a flat surface or floor. Each of the floor members is movable fore and aft, either in unison, or in opposition, to move material disposed on the floor in either a fore or aft direction. 
     Systems of the type to which this invention relates, exhibit several problems which have been the focus of industry wide research since the systems began to enjoy acceptance. A major problem is one of leakage of particulate material through the floor. Such leakage creates problems in two broad areas. First, the material that actually leaks of passes through the floor members may be lost forever to the owner, and the quantity, over a trip of several miles could be measured in tons. Secondly, if the particulate material is not lost entirely, it will most certainly accumulate beneath the floor, and in so doing, pack together, eventually raising the floor, or creating frictional loads of significant magnitude, such that efficient operation of the floor becomes gravely impaired. 
     Until the advent of the present invention, problems such as those identified continue to diminish the acceptance of walking floor systems, particularly in the transportation industry. 
     2. Overview of the Prior Art 
     The type of system for which the present invention has particular utility is illustrated generally in Wilkens U.S. Pat. No. 5,325,957 and Quaeck Pat. 5,222,593. Wilkens is also illustrative of the problem addressed by the present invention. Referring to FIG. 4, of Wilkens, the bearing surfaces  90  and  92  are abutting, as illustrated. However, as these surfaces wear, particulate matter will filter down to the space, or pocket, defined between the integral walls  88  and will, if unable to escape, build up and become impacted against the horizontal floor slat retainer surface  80 . Eventually the material will apply pressure to the surface  80 , causing the slats to skew, increasing resistance to movement, and impairing the ability of the slats to move at all. 
     A myriad of solutions can be found in the patent art, such as, for example, in Hallstrom, Jr. U.S. Pat. No. 5,267,641, in which a system is disclosed for wiping away accumulated material beneath the slats. The disclosure makes no real pretense, however, of preventing the infiltration of such material in to the guide and bearing area beneath the slats. 
     Halstrom, Jr. was prolific in this area, however, and in a related U.S. Pat. No. 5,088,595, he employs essentially the same structure to effect a waterproof seal, which is accomplished by a “U” shaped flexible fluid impervious seal,  72 , which caps abutting lateral extensions of the base members. 
     Foster, in his U.S. Pat. Nos. 4,896,761 and 4,858,748, both of which appear to have their beginnings in the same concept, employs a seal strip  38  between adjacent slats to prevent the incursion of particulate beneath the floor. Not unexpectedly, however, that seal wears and must be replaced, at a not insignificant cost. 
     Wilkens U.S. Pat. No. 5,301,798 discloses vertical bearing surfaces  84 , which the inventor states, in column  5 , acts as a seal in concert with an adjacent such surface. When wear is suffered by these surfaces, however, replacement rather than repair is the rule. 
     Quaeck also attempted to address the problem in U.S. Pat. Nos. 5,323,894 and 5,346,056, both of which sprang from the same application, by cutting a slot, or groove, in a side bearing  8 . The groove receives flanges  82  formed on the edges of the slats, and, hopefully, prevents the incursion of particulate material beneath the floor. This system, while having some superficial appearance similar to that of the seals of the present invention, is entirely different in the scheme of things, as will appear from a further reading of this specification. 
     SUMMARY OF THE INVENTION 
     The invention, which is the subject matter of this specification, comprises a novel seal/bearing arrangement, which effectively prevents the inadvertent passage of particulate material disposed on the floor of a walking floor or  reciprocating slat conveyor system, through the floor members or slats and into the area beneath the floor members. 
     Accordingly, it is a principal objective of the present invention to provide a structure that effectively seals a moving floor  reciprocating slat conveyor from the incursion of particulate material to the area beneath the floor, while coincidently providing a highly effective bearing for minimizing friction on the reciprocatable floor members. 
     It is another objective of the present invention to provide a novel walking floor  reciprocating slat conveyor which will effectively discharge particulate material that may accumulate beneath the floor members, despite the effectiveness of the sealing system, thereby avoiding the adverse consequences of such accumulation, such as packing of such material. 
     Yet another objective of the present invention is the provision of a walking floor  reciprocating slat conveyor system that is capable of being cleaned easily and effectively, both above and beneath the flooring, to eliminate contamination of particulate materials, and to preserve and enhance sealing and bearing surfaces. 
     Another, and still further, objective of the present invention is to provide a walking floor  reciprocating slat conveyor system in which the seal/bearing arrangement is sufficiently effective that the tolerances between respective parts becomes less significant than in systems currently in use. 
     A benefit, ancillary to the foregoing objective, is the ability to permit wider horizontal spacing of the slats or floor members, resulting in unsurpassed ease of installation, and a lower initial and maintenance cost. 
     The ability of the present invention to achieve these, and other objectives not specifically enumerated, will become apparent from a reading of the detailed specification in conjunction with the accompanying drawings, wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1, depicts, in perspective, an overland van with a walking floor  reciprocating slat conveyor system constructed in accordance with the present invention, installed therein, and is illustrative of one environment in which the invention has particular, although not exclusive, use; 
     FIG. 2, is a perspective view of a portion of the walking floor  reciprocating slat conveyor system of the present invention, denoted by arrow  2 — 2  of FIG. 1, illustrating in a more pictorial setting, the interrelationship of the various elements of the system; 
     FIG. 3, is an exploded view of an assemblage of parts comprising the novel sealing/bearing system of the present invention; 
     FIG. 4, is a side elevation  cross- sectional view  of the walking floor  reciprocating slat conveyor of the present invention, sectioned to further define the working relationship of the floor elements, and particularly the seal/bearing area; and 
     FIG. 5, is an enlarged perspective view of the area encircled by line  5 — 5 in FIG.  4   2 , to show the specific seal/bearing area in greater detail, such view showing fragmentary portions of the floor beams in section. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     With reference now to the drawings, and initially to FIG. 1, a van, V, is illustrated to provide one environment in which the present invention finds particular utility. 
     The van V, as shown, comprises an open top configuration which permits loading from the top. However, a closed top van, or vans of other configurations familiar to the over-the-road hauler, could be similarly equipped with the moving floor system of the present invention without departure therefrom. 
     As earlier stated, the floor system of the present invention is equally adaptable to warehouse, or stationary applications, but since the over-the-road application seems to create the most challenging environment for such systems, that environment has been chosen for the following description. 
     In accordance with the invention, a novel walking floor  reciprocating slat conveyor system  10  is installed in the van V. The floor system  10  is disposed longitudinally within the van in order to unload the van from the forward end  12 , toward the rear end  14 . The load within the confines of the van is protected from inadvertent discharge by doors  16 , illustrated in the open position. The van is supported by rear wheels  18 , and is towable by a fifth wheel system (not illustrated) or by any other well known arrangement. 
     The floor system  10  is perhaps best illustrated in FIGS. 2 through 5, and referring to FIG. 2 in particular, there is shown a plurality of reciprocatable floor members, or beams,  21 , disposed in parallel relation. Each such floor beam comprises a horizontally disposed plank, or slat, portion  23 , having a flat surface defining a load receiving face  25 . The face portions of adjacent ones of said beams are coplanar, thereby presenting, in unison, a relatively flat, level surface upon which a particulate, or other load, may be firmly supported. 
     In order to provide support for the floor beams  21 , the invention contemplates the use of a slotted subfloor, comprising a series of spaced support members  27 . The support members  27  are supported within the van V by its own frame structure, such that the support members run transverse to the longitudinal axis of the van and are secured to the framework of the van V in spaced relation relative to one another. The support members, in addition to providing necessary and uniform support for the floor beams  21 , provide rigidity and support for the van V. 
     The spacing of the support members  27  is a matter of intelligent choice, dictated to a substantial extent, by the weight to be supported by the support members, including the walking floor  10  and the maximum loads which are contemplated for the van&#39;s capacity. 
     As is the case with competitive walking floors  reciprocating slat conveyors, the floor slats or beams are moved fore and aft along the longitudinal axis of the van V. They may be moved in one direction or the other, either in unison or in some alternative pattern, as may be desirable, but in any event, in an well known manner. Since such beams are long in their direction of movement, it is necessary to provide guidance for such movement to avoid misalignment, the inevitable consequence of which is the breakdown of the sealing arrangement and increased friction with coincident increases in wear, just to name a few. 
     Accordingly, guidance is provided for the floor beams  21  by guide members  30 . Each guide member  30  is secured to the support members  27  by means of fasteners  31 , which may be of any well known construction or type not inconsistent with the task of holding the guide members  30  securely in alignment. 
     Each guide member  30  is configured so as to be partially encircled by a floor beam  21 . More specifically, and referring in particular to FIG. 4, each guide member  30 , comprises an elongated strip, or more accurately, a series of strips joined together at their ends to form a rail upon which the floor beam  21  may reciprocate. 
     In order to optimize the performance of the guide members  30 , they are shaped, in profile, in a substantially rectangular configuration with an upper body portion  32 , having arcuate, or rounded, upper corners  34 , the upper body portion  32  being supported on a lower body portion or stem  36 . The lower body portion is, as seen in FIG. 4, secured to the lower support members  27 , by fasteners  31 . 
     Again referring to FIG. 4, and additionally to FIG. 3, each floor beam is formed with a pair of opposed depending “L” shaped legs  41 . The “L” shaped legs  41  combine to define a channel beneath the plank portion  23 , which channel is dimensioned to embrace the upper body portion  32  of the guide members  30 , with inwardly turned flange portions  43 , of legs  41  cupped beneath the lower surface  45  to secure the floor beam  21  from raising up from its position on the guide member  30 . 
     In order to provide a minimum lateral or torsional movement, or torquing, of the floor beams during operation, they must fit as closely as possible about the guide members  30 . Naturally, the more secure the fit the greater likelihood of frictional resistance to movement. In order to minimize frictional resistance to reciprocation of the floor beams, it is contemplated that the guide members be formed, or constructed of a high molecular weight resinous material, sometimes referred to in the trade as UHMW material. Such materials, which are available from several manufacturers, are strong, easily formed to a predetermined configuration, and have exceptionally low surface abrasion, which translates into an excellent bearing relationship between adjacent parts, even if the load on a particular floor beam is such that the beam is forced into contact with the guide member, or is unbalanced, creating upward forces on the lower surface  45  of the upper portion of the guide member. 
     An important feature of the present invention is the use of a novel bearing/seal system, which is perhaps best illustrated in FIG.  5 . The essence of this seal arrangement is to prevent, insofar as may be realistically possible, the incursion of particulate materials, including “fines” of 100 mesh or better, into the pocket areas beneath the floor area, as may be observed in FIGS. 2 and 4. 
     In accordance with this aspect of the invention, intermediate spaced longitudinal guide members, and equidistant therebetween, the present invention provides a bearing/seal member  50 . Each such bearing/seal member  50  parallels its adjacent guide members  30 , and comprises a base member  52 , which is secured to the subfloor support members  27 , by means of a fastener  54 , of well know construction. The base member supports a seal plate, or cap,  56  on its upper surface  58 , which is secured by fasteners  60 , which, as illustrated, comprise rivets of a compatible material such as UHMW. 
     In order to minimize friction and wear, even in the presence of heavy loads, the seal plate is preferably constructed of a material such as UHMW materials as previously described. 
     It will be observed in FIGS. 2 through 5 that the longitudinally extending side walls  63  of the plank portion  23  of the floor beams terminate in a downwardly extending ear  65 , having an end, or termini,  67 , which is formed with a small radius so as not to present a sharp edge to the seal plate. As seen in FIG. 5, the end  67  of the ear  65  engages the surface of the seal plate  56 . As shown by FIGS. 2-5, the conveyor slats or beams  21  have upper side portions that project horizontally outwardly from the lower side portions or legs  41 . The upper side portions include lower surfaces and ears  65 . The ears  65  are depending, longitudinal edge forming portions. They depend below the lower surfaces and include lower edges  67  that contact the seal plate  56  and space the lower surfaces above the bearing/seal surfaces on top of members  56 . 
     When the floor beam is under load, the end of the ear  67  and the seal plate  56  form an effective and very simple seal against the incursion or migration of particulate material to the subfloor area. Indeed, with time, the end  67  of the ear will form, by continuous reciprocal movement, a groove  70  in the face of the seal plate, which will, with wear, conform closely to the configuration of the end  67 . Thus, as the seal plate wears in, the amount of surface area contact between the ear and the seal plate increases with the result that, with such greater surface contact, the seal becomes further enhanced as the ear  65  rides in that groove. 
     Because the wear is light, relatively speaking, the service period for a seal plate is quite long, much longer than industry expectations, and the maintenance associated with the novel floor of the present invention is coincidently, exceptionally good. 
     Thus, the pockets, or voids, defined by the bearing/seal members  50 , and the guide members  30  remain exceptionally free of particulate material. Moreover, because the seal plate is of a low friction, high density material, it doubles as a bearing member, both supporting the floor beam, and providing the desired seal. Hence, the name bearing/seal. 
     The present invention further provides a novel system that has the added feature of being essentially self cleaning. Extreme “fines” are sometimes capable of passing the most effective seal, and when the floor is not under load, the seal formed by the present invention is somewhat less effective. In anticipation of at least some passage of particulate, the present invention simplifies the cleaning process, in avoiding the adverse consequences of build up in the pockets beneath the floor by spacing the support members  27 . In this manner, any build up will pass beneath the subfloor, avoiding build up of material and consequent back pressure on the floor beams.