Reciprocating slat conveyor

An improved front-drive reciprocating slat conveyor has a plurality of sets of longitudinally extending slats spaced across the width of a receptacle floor. A cross beam is secured to each set of slats. The cross beams are secured to rod extensions that are connected to the piston rods of a hydraulic drive system by non-alignment critical connectors. The cross beams have connecting elements that engage receiving elements on the slats. The connecting elements and receiving elements are held together by pins or similar connectors. A frame extends across the width of the receptacle. Bearing guides guide and align the rod extensions when the cylinder rods are extended or retracted.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to reciprocating slat conveyors for loading or unloading cargo from a receptacle and, more particularly, to reciprocating slat conveyors having sets of slats that can be simultaneously or sequentially moved to offload bulk cargo.

2. Technical Considerations

Conventional reciprocating slat conveyors are used for loading and unloading receptacles with bulk cargo, such as garbage, fertilizer, wood chips, sawdust, and the like. The receptacles can be mobile, such as a trailer, or fixed in place. The conveyor floor includes sets of slats having individual slats spaced across the width of the receptacle. The slats are joined to a cross member extending across the width of the floor. A hydraulic drive having hydraulic cylinders is typically positioned in the middle of the conveyor floor or at the front of the trailer to move the slats. The cylinders can be actuated to move all of the slats simultaneously to load or unload the receptacle or to move the sets of slats sequentially to retract the sets of slats back to a starting position.

A problem with conventional mid-drive and front-drive slat conveyors is that the lateral torque absorbed in the cylinder rods can damage the rods or cause the screws connecting the rods to the slats to wear. The rods extend through a front support frame, where torque is transferred to the rod. The rods are rigidly connected to the slats and any torque caused by misalignment of the slats is transferred to the rods. Also, the drive components can become fouled, dirty, or corroded due to material falling through the slats onto the drive components. Moreover, these conventional drive systems do not have non-leak proof capability.

Therefore, it would be advantageous to provide a slat conveyor system that reduces or eliminates at least some of these problems. For example, it would be advantageous to provide a front-drive slat conveyor in which the torque transferred to the rods can be reduced. It would also be advantageous to provide a leak-free slat conveyor system.

SUMMARY OF THE INVENTION

An improved front-drive reciprocating slat conveyor of the invention has a plurality of sets of longitudinally extending slats spaced across the width of a receptacle floor. A cross beam is secured to each set of slats. The cross beams are secured to rod extensions that are connected to the piston rods of the hydraulic drive system cylinders by non-alignment critical connectors. The cylinders are secured to the receptacle by non-alignment critical connections. The cross beams are connected to the slats. A frame interacts with the cross beams to define bearing guides that guide the rod extensions when the cylinder rods are extended or retracted.

The slats move along support beams in the receptacle. Bearing sleeves are provided that have an inner shape complementary to at least a portion of the outer shape of the support beams such that the bearing sleeves can be slid along and held in place on the support beams. The slats have an inner shape that is complementary to at least a portion of the outer shape of the bearing sleeves to help maintain the slats engaged with the bearing sleeves during operation.

A reciprocating slat conveyor comprises a plurality of slats arranged in a plurality of slat sets, with each slat having a receiving element formed on top of the slat; a cross beam assembly connected to the slats, wherein the cross beam assembly includes a plurality of rod extensions, with one cross beam connected to each rod extension, wherein each cross beam includes a plurality of connecting elements configured to engage the receiving elements on the slats; a frame configured to engage the cross beam assembly, the frame defining a plurality of bearing guides configured to guide the rod extensions for lateral movement; and a drive assembly comprising a plurality of cylinders, with each piston rod connected to a rod extension by a non-alignment critical connector.

A deck assembly comprises longitudinal support beams, with each support beam having an exterior profile; plastic bearing sleeves, with each bearing sleeve having an interior profile complementary to at least a portion of the exterior profile of the support beam and slidable along the support beam; and slats having an interior profile complementary to at least a portion of the outer profile of the bearing sleeve and configured to slide along the bearing sleeve.

A deck assembly includes interconnecting adjacent support beam members, wherein the deck assembly also includes a first support beam member having a base and an upwardly extending support element having a groove; and a second support beam member has a base and an upwardly extending support element having a projection, wherein the projection is configured to engage the groove to interconnect the adjacent support beam members.

A deck assembly includes interconnecting adjacent support beam members, wherein the deck assembly also includes a first support beam member having a base and an upwardly extending profiled support; and a second support beam member having a base and an upwardly extending profiled support, wherein the bearing sleeve engages the profiles of adjacent support and the slat engages the bearing sleeve, wherein the slat includes a groove on one side configured to accept an end of an elastomeric bearing element that extends into a receiving groove in an adjacent slat.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, spatial or directional terms, such as “left”, “right”, “inner”, “outer”, “above”, “below”, “top”, “bottom”, and the like, relate to the invention as it is shown in the drawing figures. However, it is to be understood that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. Further, as used herein, all numbers expressing dimensions, physical characteristics, and the like, used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical value should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass the beginning and ending range values and any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, e.g., 1 to 3.3, 4.7 to 7.5, 5.5 to 10, and the like. As used herein, the terms “polymer” or “polymeric” include oligomers, homopolymers, copolymers, and terpolymers, e.g., polymers formed from two or more types of monomers or polymers. Additionally, all documents, such as but not limited to issued patents and patent applications, referred to herein are to be considered to be “incorporated by reference” in their entirety.

A cargo receptacle suitable for use with a reciprocating slat conveyor of the invention is shown inFIGS. 1 and 2. In the illustrated embodiment, the receptacle is depicted in the form of a conventional trailer10having a load support floor16. However, it is to be understood that the invention is not limited to trailers but could also be practiced with other types of containers, such as but not limited to ground based containment bins. As will be appreciated by one skilled in the art, slats on the support floor are movable back and forth longitudinally within the trailer10by a drive assembly having extensible and retractable piston rods. The slat conveyor also includes a cross beam assembly and a rigid frame.

The front of the trailer10houses the drive system, as will be described below. The trailer10shown inFIG. 2is a substantially rectangular trailer having a body with a left sidewall12, a front wall14at a front end of the trailer10, a support floor16, and a rear discharge end. The right sidewall and top of the trailer10are not shown for ease of description of the invention. The front wall14includes an opening through which the piston rods of the drive assembly extend and interact with the cross beam assembly of the invention. The interior of the trailer10defines a cargo receiving compartment.

A diagonal slope sheet18extends across the width of the trailer10and downwardly from the front wall14. The upper end of the slope sheet18is secured to the interior of the front wall14and the lower end is secured above a cover plate. The sides of the slope sheet18are fixed to the side walls of the trailer10. The slope sheet18can include an access door to provide access to the area under the slope sheet for inspection and cleaning.

A support floor20comprises a plurality of elongated load support slats22spaced side-by-side across the width of the floor20. A leak-proof seal, such as a pan23(seeFIG. 3), is positioned under the slats22along the length of the conveyor to prevent liquid and debris falling through the bottom of the trailer10. The drive assembly moves the slats22longitudinally back and forth (fore and aft) between the rear discharge end and the front end of the trailer10. The slats22are grouped into a plurality of slat sets. For ease of discussion, the invention will be described with reference to three slat sets. However, it is to be understood that any number of slat sets could be defined. The slat sets can be moved either all together or selectively by the drive assembly.

FIG. 3shows the front interior of the trailer10with the slope sheet18removed exposing a cross beam assembly26and a frame28of the invention. As shown inFIGS. 3 and 4, the cross beam assembly26is connected to a drive assembly30. In the illustrated embodiment, the drive assembly30includes three cylinders32, each having an associated piston34. The cylinders32are positioned such that the pistons34extend from the rear end of the cylinder32(with respect to the trailer). The cylinders32can be hydraulically or pneumatically operated. The front ends of the cylinders32include an attachment device to attach the front ends of the cylinder to the trailer10or a support.

As shown particularly inFIG. 4, the cross beam assembly26includes a plurality of rod extensions36. Each rod extension36is connected to an individual piston rod34by a non-alignment critical connector, such as a conventional swivel socket or similar device to permit relative movement between the end of the piston rod34and the rod extension36. For example, the rod extensions36can be connected to the piston rods34by a U-shaped connector and pin assembly that permits some degree of movement or misalignment between the rod extensions36and the piston rods34to help offset any damage that could be caused by twisting or torque forces generated during operation of the conveyor. In the illustrated embodiment, the rod extensions36are configured as hollow, substantially rectangular metal pieces. The cross beam assembly26also includes a plurality of laterally extending cross beams38. Each cross beam38is connected to one of the rod extensions36. Each of the cross beams38includes a plurality of connecting elements40depending therefrom. In the embodiment shown inFIG. 4, the connecting elements40are shown as elongated metal elements or “feet” depending from the bottom of the cross beams38. The connecting elements40are configured to engage receiving elements42on the slats22such that each connecting element40is connected to a single slat22. For example, the rear end of each foot can include an attachment element44, such as a threaded bore, that can be used to connect the foot to one of the slats22. In this embodiment, the foot is connected to the slat22by a single connection point.

The conveyor assembly26also includes guides46through which the rod extensions36slide. The guides46can take the form of metal channels in which the rod extensions36slide to help ensure linear movement of the rod extensions36and to help prevent twisting or non-linear movement of the rod extensions36during operation of the conveyor. The top of the guides can form or can include a guidance device, such as a flange48or wing, extending horizontally from the top of the guide wall. These flanges48can be located above the top of the rod extensions36to engage the frame, as will be described below. Friction bearings50, such as low friction material, such as a polymeric material, can be positioned on the cross beam assembly26such that the rod extensions36contact the low friction material to reduce the friction as the rod extensions36are sliding forward and aft. The friction bearings50also contain lateral and torsion forces. In the illustrated embodiment, the cross beam assembly26also includes three stabilization members52in the form of elongated, rectangular metal members attached to one of the cross beams38. Guide members, such as bearings, such as roller bearings54, on top of the cross beams38engage the stabilization members52as the cross beams38are moved fore and aft. The stabilization members52and roller bearings54also help prevent torquing and misalignment of the cross beams38as they are moved fore and aft.

FIG. 5shows the cross beam assembly26with the connecting elements40connected to the receiving elements42on the top of the slats22. The receiving elements42can take the form of metal brackets or channels connected to the top of each slat22. Each receiving element42also includes an engagement member, such as a vertical piece56having a hole that aligns with the bore in the connecting element40. A connector, such as a screw or bolt, can be passed through the hole in the vertical piece56to engage the bore in the connecting element40to attach the slat22to the connecting element40. This provides for a one point connection between the connecting element40and the slat22. Also, since the connecting element40is attached to the top of an associated slat22, this means that there is no need to break through the leak-proof seal (such as the pan23) to engage the slat22with the connecting element40of the cross beam assembly26.

FIG. 6shows the cross beam assembly26mounted in the front of the trailer10. The piston rods34of the drive assembly26extend through a hole or passage in the front of the trailer10and are connected to the rod extensions36. As can be appreciated fromFIGS. 4 and 6, the cylinders32are mounted at an angle with respect to the rod extensions36. For example, the front end of each cylinder32can be located in the range of 1 inch to 5 inches, such as 2 inches to 4 inches, such as 3 inches, higher than the rear end of the cylinder32. Thus, the drive assembly30, cross beam assembly26, and slats22are all located above the pan23so that no part of the conveyor has to extend through the pan23, which maintains the leak-free characteristics of the conveyor system of the invention. Also, this means that the cylinder32and associated rods34operate in one plane while the rod extensions36operate in a different plane. The slats22operate in a plane parallel to the plane of the rod extensions36.

FIG. 7shows the frame28positioned over the cross beam assembly26. The frame28can be connected to the sides of the trailer10and the bottom of the frame28can press downwardly on the top of the guide flanges48to prevent the rod extensions36from moving vertically and/or horizontally out of the guides46during operation of the conveyor. A low friction bearing, such as a polymeric friction pad, can be positioned between the bottom of the frame28and the top of the cross beam assembly26to reduce any friction caused by movement of the rod extensions36against the bottom of the frame28.

As shown inFIG. 8, the front ends of the cylinders32of the drive assembly30are connected to the trailer10or to a support of the trailer10. The front ends of the cylinders32are connected to the support by a non-alignment critical bearing60. In the illustrated embodiment, this non-alignment critical bearing60can be a swivel socket or any other conventional means to allow swiveling or movement of the front end of the cylinder32to account for movement or misalignment during operation of the conveyor. As also shown inFIGS. 8 and 4, electronic position sensors62are located on or near the cylinders32of the drive assembly30to detect when the piston rods34have reached their maximum or minimum stroke. In the illustrated embodiment, these position sensors62are in the form of electronic proximity detectors having a metal piece and a magnetic detector. Unlike prior conveyors that utilize complex hydraulic circuits, the conveyor of the invention utilizes an electrical sequencing assembly incorporating the electronic position sensors62rather than hydraulic pop-it valves to detect the cylinder strokes. The sensors62are connected to an electronic control device, such as a conventional digital computer, such as a programmable logic controller (plc) device, to control operation of the conveyor. This electronic control greatly simplifies the hydraulic circuit of the invention since conventional throw in/throw out valves can be used rather than the complex valves of prior systems.

FIG. 9shows a cross-sectional view of a deck assembly64of the invention. The deck assembly64includes support beams66having an exterior profile. In one aspect of the invention, bearing sleeves68of a low friction material, such as a plastic material, are connected to the support beams66by slipping one end (forward end) of the bearing sleeve68onto the end of the support beam66and then pushing the bearing sleeve68forward so that the inner profile of the bearing sleeve68mates with at least a portion of the outer profile of the support beam66. The bearing sleeves68have an inner profile that is complementary to at least a portion of the outer profile of the support beams66to keep the bearing sleeves68in place. The bearing sleeve68can be retained on the support beam66by an end cap or similar fastening device at the rear end and the front end of the support beam66. The front end of the bearing sleeve68can abut against the front wall14of the trailer10. Thus, the bearing sleeve68can extend along substantially the entire length of the support beam66. As shown inFIG. 9, the slats22have an inner profile that is complementary to at least a portion of the outer profile of the bearing sleeve68to help mate the slat22to the bearing sleeve68(and thus the support beam66). One side of the slat22can have a channel67and the other side of the slat22can have a groove69. The slats22are positioned such that the channel67of one slat faces the groove69of the adjacent slat22. A flexible member71has one end73configured to engage the channel67and another end75configured to extend into the groove69. The flexible member71helps reduce or prevent debris from falling through the gap between adjacent slats22. For example, the bearing sleeves68and slats22can be installed and then the flexible member71slid into the channel67and groove69at the rear of the conveyor and pushed forward to the front of the conveyor. An end cap can be attached at the rear end of the conveyor to keep the bearing sleeves68and flexible members71from sliding out of the deck assembly70.

Another deck assembly70is shown inFIG. 10. This deck assembly70is particularly useful for leak-free systems to prevent debris from dropping onto the roadway through the bottom of the trailer. In this configuration, a non-porous pan may be installed in the trailer10or a leak-free deck can be formed as the deck assembly is formed. The support beams can be formed by adjacent and interconnecting support beam members extending laterally along the floor of the trailer. One support beam member72(left side inFIG. 10) has a base74and a support element76extending upwardly therefrom. The support element76has a notch or groove78along an inner side. The second support beam member80(right side inFIG. 10) also includes a base82with an upwardly extending support element84having an extension or projection86configured to engage the groove78on the first support element76to connect the adjacent support beam members72,80together. This arrangement reduces the number of bolts or connectors needed to form the deck assembly since adjacent pieces interconnect with each other and do not have to be individually secured to the deck of the trailer. An elastomeric member, such as an elongated polymeric strip88, can be positioned in a channel90formed between the first support element76and second support element84to seal the support elements. In one embodiment, the adjacent support beam members72,80themselves form a leak-free seal on the trailer floor and the separate pan23may not be needed.

FIG. 11shows another leak resistant deck assembly92having adjacent support beam members94that can be interlocked and interconnected. Each support beam member94has a pair of inwardly facing profiled supports96extending upwardly from a base98. The bearing sleeve68is positioned over the profiles of adjacent support beam members94and the slat22is positioned to engage the bearing sleeve68. As shown inFIG. 11, each slat22can have a groove100in one side configured to accept an end of an elastomeric bearing element, such as a plastic strip102, that extends into a receiving groove104on the adjacent slat22. This provides a leak-resistant sub deck to prevent particles passing through the bottom of the trailer.

Operation of the conveyor assembly will now be described. When all of the piston rods34are extended at the same time, the cross beams38simultaneously move the three sets of slats22toward the rear discharge end to move cargo resting on the slats22rearward a distance equal to the length of the discharge stroke. Upon completion of the discharge stroke, the drive assembly30sequentially moves or retracts the sets of slats22forwardly by moving one slat set (one cross beam38) at a time toward the front of the trailer10so that the slats22are repositioned to the front of the trailer10without moving the cargo forward. The withdrawal stroke distance is equal to the discharge stroke distance. The drive assembly30is reversible so that the slat conveyor can move a load from the discharge end of the trailer10to the front wall of the trailer10for loading.

FIG. 12shows another conveyor incorporating features of the invention. The conveyor is shown positioned in the front of a conventional trailer. As shown inFIGS. 12 and 13, the conveyor includes a cross beam assembly110connected to a drive assembly112. The drive assembly112can be the same as the drive assembly30described above with respect to the previously described conveyor. Each cylinder114of the drive assembly112has a piston116connected to a rod extension118of the cross beam assembly110. The connection between the piston rod116and rod extension118is a non-alignment critical connection, such as a swivel joint or similar connection to allow angular movement between the end of the piston rod116and the rod extension118. Each rod extension118is connected to one cross beam120. In the illustrated embodiment, each rod extension118is connected at or near its rear end to a selected cross beam120by a mounting plate122. The rod extension118is connected to the top of the mounting plate122and the mounting plate122is connected to the cross beam120in any conventional manner, for example, by welding, bolts, screws, or any conventional connector. Connecting elements124are attached to the bottom of the cross beams120, as described above. The connecting elements124are in the form of rectangular metal pieces having a rear end with an attachment element126, such as a bore or similar attachment element therein. This is similar to the connecting elements40described above. However, in this embodiment, the connecting elements124also include a front connector128. In the illustrated embodiment, the front connectors128are shown as tabs or extensions having aligned holes that can receive a connecting element, such as a pin or screw or the like.

FIG. 14shows the cross beam assembly110connected to slats130. As will be appreciated fromFIGS. 14 and 15, the slats130include a receiving element132similar to the receiving element42described above having a vertical piece134with a hole that aligns with the bore in the rear end of the connecting element124. However, unlike the previously described receiving element42, the receiving element132of this embodiment also includes a forward connecting device136so that both the rear end and the front end of the connecting element124are attached to the slat130. In the illustrated embodiment, the front connecting device136is in the form of a pair of holes on the upstanding wall of the receiving element. When the connecting element124is inserted into the slot of the receiving element132, the rear end of the connecting element124abuts the vertical plate134and can be connected as described above. The holes of the front connector128align with the holes in the front connecting device136of the receiving element132such that the front end of the connecting element124can be secured to the front end of the receiving element132by a screw, bolt, pin, or other means and the front end of the connecting element124can be secured to the front end of the slat130by a pin or similar device passing through the aligned holes in the receiving element132and the connecting element124.

FIG. 16is an end view of the conveyor assembly ofFIG. 12. In this embodiment, the leak-free pan23is positioned in the trailer10and longitudinal support beams140are attached to the pan or the bottom of the trailer. Longitudinal bearing sleeves142, such as those described above, are connected to the support beams140. The slats130are engaged with the bearing sleeves142and are moveable fore and aft on the bearing sleeves142by extension and retraction of the piston rods116of the drive assembly112. As will be appreciated fromFIG. 16, space is provided between adjacent slats130such that any accumulated debris can be swept, blown, or otherwise removed from the trailer10when the trailer10is desired to be cleaned.