BACKGROUND

The invention relates to a reciprocating slat conveyor comprising multiple parallel slats that are slidable in the longitudinal direction with respect to each other by means of a drive mechanism. Such reciprocating slat conveyors are able to load and unload cargo without additional loading equipment on the reciprocating slat conveyor .

Reciprocating slat conveyors for bulk goods have seals present between the slats to prevent penetration of particles or dirt through adjacent slats or to prevent passage of upwardly spraying water or dirt when the conveyor forms part of a trailer. A tight sealing is required over the entire length. The seals are subject to wear while a reliable sealing is required over a long time.

It is an object of the present invention to provide a reciprocating slat conveyor of the abovementioned type, with seals that are optimized to sealing properties and stand time.

SUMMARY OF THE INVENTION

The invention provides a reciprocating slat conveyor comprising a support structure, multiple parallel slats that are supported by the support structure and that are slidable in the longitudinal direction with respect to the support structure, a longitudinally extending seal between adjacent slats, and a drive mechanism for reciprocating sliding movement of the slats with respect to the support structure, wherein the slats comprise a top wall, and a left sidewall and a right sidewall that both extend downward from the top wall, wherein the top wall comprises a projecting edge that projects with respect to the left side wall towards the top wall of the adjacent slat to form a space between the left sidewall and the right sidewall of the adjacent slat for the seal, wherein the projecting edge comprises a support surface section that is oriented obliquely in the upward direction towards the adjacent slat, wherein the seal comprises a base body that is confined in a longitudinally extending locking chamber in the left sidewall, and a first leg that projects upwards from the base body towards the projecting edge, wherein the first leg comprises an engagement section at its free end and a compression section between the engagement section and the base body, wherein the engagement section comprises a sealing edge or tip that is in abutment with the adjacent slat, and a first engagement surface that is in abutment with the support surface section, wherein the compression section is in biased compressed state to keep the sealing edge or tip and the first engagement surface in abutment.

The reciprocating slat conveyor according to the invention comprises a seal between adjacent slats that is protected by the projecting edge. The engagement section at the free end of the first leg is in sealing abutment with both the adjacent slat and the support surface that is oriented obliquely towards the adjacent slat. The biased compression section behind the engagement section maintains the tight sealing abutment of the wedging engagement section, also on the longer term when the first leg becomes slightly shorter due to wear.

In an embodiment the first leg comprises as from the base body a first compression section that thickens towards the free end and that merges into a second compression section that narrows towards the free end, wherein the first engagement surface extends along the second compression section. The first leg may thereby have its largest width and therefore its highest stiffness at the merger between the first compression section and the second compression section. The first engagement surface extends along that second compression section and thus as from the part of the first leg with the highest stiffness to remain well positioned against the support surface section. This ensures a proper sealing engagement of the sealing edge or sealing tip against the adjacent slat.

In an embodiment the support surface section is a straight surface.

In an embodiment the first engagement surface is a straight surface both in the biased state and in a relieved state of the compression section. The straight surface in cooperation with a straight support surface provides a large contact surface between the slat and its seal. This large contact surface provides a long penetration path, and thus an effective sealing on the long term.

In an embodiment thereof the seal has transverse to the longitudinal direction of the first engagement surface a width that is at least 20%, preferably at least 40% of the largest thickness of the first leg.

Quantitatively defined, the first engagement surface engages the support surface section with at least 80% of its surface.

In a specific embodiment thereof the first engagement surface engages the support surface section with at least 90% of its surface.

In a more specific embodiment thereof the first engagement surface engages the support surface section with 100% of its surface.

In an embodiment the first engagement surface extends parallel to the support surface section. In an embodiment the left sidewall comprises an outer surface section between the support surface section and the locking chamber that merges over an angle into the support surface section, wherein the seal comprises a second engagement surface that is in abutment with the outer surface section. The abutment of the outer surface section and the second engagement section provides additional penetration path, and thus an effective sealing on the long term.

In an embodiment thereof the outer surface section is a straight surface.

In an embodiment the second engagement surface is a straight surface both in the biased state and in a relieved state of the compression section. The straight surface in cooperation with a straight outer surface section provides a large contact surface between the slat and its seal. This large contact surface provides a long penetration path, and thus an effective sealing on the long term .

In an embodiment the seal has transverse to the longitudinal direction of the second engagement surface a width that is at least 20%, preferably at least 40% of the largest thickness of the first leg.

Quantitatively defined, the second engagement surface engages the outer surface section with at least 80% of its surface.

In a specific embodiment the second engagement surface engages the outer surface section with at least 90% of its surface.

In a more specific embodiment the second engagement surface engages the support surface section with 100% of its surface.

In an embodiment the second engagement surface extends parallel to the outer surface section.

In an alternative embodiment the first leg extends free from the slat between the abutting engagement surface and the base body. This clearance ensures that the first leg remains movable, compressible and extendable with respect to the base body even when the adjacent slats are fully abutting each other or when dirt has penetrated between the support surface and the first engagement surface .

In an embodiment the locking chamber comprises a passage section that debouches in an outer surface section of the left side wall, and a wider confinement section within the left side wall, wherein the base body comprises a neck that extends through the passage section and a wider head that is confined in the confinement section.

In an embodiment thereof the head comprises a lower locking body and an upper locking body that project mutually oppositely outward from the neck, wherein the lower body and the upper body are positioned staggered with respect to each other in the direction from the neck towards the head. The staggered mutual position allows the allocation of a spot where accumulation of dirt or oxidation has less impact onto the position of the seal with respect to the locking chamber.

In an embodiment thereof the lower locking body and the upper locking body have the same thickness in the direction from the neck towards the head, whereby its rigidity is constant over the entire height of the head.

In an embodiment the seal comprises a second leg that projects downwards from the base body and that is in abutment with the adjacent slat.

In an embodiment the slats are prismatic, whereby they can be manufactured by extrusion.

In an embodiment the slats are made of a metal or a hard plastic.

In an embodiment the seal is prismatic.

In an embodiment the seal is made of plastic, in particular a rigid plastic having a rigidity which is less than the rigidity of the material of the slats, whereby the seal may wear faster than the slats. The seal may be provided as a replaceable wearing part . In an embodiment the seals are made of a rubberlike or flexible material.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which:

Figure 1 shows a trailer with a reciprocating slat conveyor according to an embodiment of the invention;

Figure 2 shows the part of the reciprocating slat conveyor as indicated in figure 1, wherein some slats have been removed or cut off for illustrative purposes only;

Figure 3 shows a cross section of the reciprocating slat conveyor of figure 1 at one of its first seals according to the invention;

Figures 4A and 4B show cross sections of the first seal in operational state as shown in figure 3 and in relieved state, respectively;

Figure 5 shows the first seal separately;

Figure 6 shows a cross section of the reciprocating slat conveyor of figure 1 at one of its alternative, second seals according to the invention;

Figures 7A and 7B show cross sections of the first seal in operational state as shown in figure 3 and in relieved state, respectively; and

Figure 8 shows the first seal separately.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a trailer 1 with a reciprocating slat conveyor 10 according to an embodiment of the invention. The trailer 1 comprises two longitudinal frame bars 2 and multiple transverse frame bars 3 mounted thereon, and a schematically indicated hood 5 that covers the area above the reciprocating slat conveyor 10. The trailer 1 furthermore comprises multiple wheel axes 4, and two retractable stands 6 to support the uncoupled trailer 1. The reciprocating slat conveyor 10 according to the invention is not limited to trailer applications, but can also be applied in trucks or in fixed structures. The reciprocating slat conveyor 10 is configured to move cargo forwards and backwards in its longitudinal direction L as described hereafter.

The reciprocating slat conveyor 10 is shown in more detail in figure 2. The reciprocating slat conveyor 10 comprises multiple prismatic slats 20 that extend parallel and adjacent to each other. In this embodiment the slats 20 are made of metal, for example aluminum, by extrusion. The slats 20 are supported by slide bearings 9 that are mounted on the transverse frame bars 3. The slide bearings 9 allow sliding movement of the slats 20 only in the longitudinal direction L. The subsequent slats 20 form repetitively and subsequently part of a first group, a second group or a third group of slats and are per group connected to a respective drive beam 11. For this connection multiple connectors 12 having mounting holes 14 are welded onto the drive beams 11. As best shown for the slat 20 that has been shown cut off for illustrative purposes only, each slat 20 is provided with a series of mounting holes 23 that correspond with the mounting holes 14 of the connectors 12 to receive series of bolts 30. The bolts 30 are fixated by means of steel strips 13 that are inserted in the connectors 12 and that are provided with threaded holes 15 for the bolts 30. The drive beams 11 form part of an hydraulic drive system that is known per se and therefore not shown in the drawings. This hydraulic drive system is configured to shift one of the groups of slats 20 in the longitudinal direction L with respect to the remaining groups of slats 11 in subsequent cycles whereby cargo on the slats 20 slides in the longitudinal direction L only in one loading direction or unloading direction. The slats 20 move parallel to each other while remaining in the same horizontal plane, that is without mutual vertical movements .

Figure 3 shows a cross section of two of the adjacent identical slats 20 at the location of the facing parts thereof. Each slat 20 comprises a top wall 21 with in this example a horizontally extending straight top surface 22, and a right sidewall 30 and a left sidewall 40 pending downwards therefrom to form a U-configuration . In this regard it is noted that "horizontally", "vertically", "left" and "right" are non-limiting relative references.

The slats 20 comprise a straight right outer surface 31 on the right sidewall 30 that extends perpendicular to the top wall 21 and the top surface 22 thereof. The right sidewall 30 extends up to the top surface 22 of the slat 20.

The slats 20 comprise a straight first left outer surface section 41 on the left sidewall 40 that extends perpendicular to the top wall 21 and the top surface 22 thereof. The first left outer surface section 41 merges into a straight support surface section 42 that extends obliquely to the first left outer surface section 41. The support surface section 42 merges into a straight second left outer surface section 43 that extends perpendicular to the top wall 21 and the top surface 22 thereof and that extends up to the top surface 22. The support surface section 42 extends under an angle W of 40-50 degrees, in this example 45 degrees with respect to the top wall 21 and the horizontal main plane or top surface 22 thereof, or with respect to the first left outer surface section 41 and second left outer surface section 43, or with respect to right outer surface 31 of the adjacent slat 20. The top wall 21 defines straight above this oblique support surface section 42 a projecting nose or edge 24 that faces the top wall 21 of the adjacent slat 20. The third left outer surface section 43 extends parallel to the right outer surface section 31 of the adjacent slat 20.

The slats 20 comprise a locking chamber 45 inside the left side wall 40 that debouches in the first left outer surface section 41. The locking chamber 45 comprises a passage section 46 that is bounded by two opposite locking edges 47 that are in this example circularly rounded in their cross section. The locking chamber furthermore comprises a wider confinement section 48 that is bounded by a bottom surface 50, a top surface 51 and a back surface 52 that in cross section together define a substantially rectangular contour and circularly rounded corners. The first left outer surface section 41 extends parallel to the right outer surface section 31 of the adjacent slat 20 and is recessed thereof to provide clearance or a space 32 for a first seal 60 according to the invention as shown in figures 3-5, or alternatively a second seal 160 according to the invention as shown in figures 6-8 that are mounted to the slat 20 by means of insertion in their elongate direction into the locking chamber 45. The seals 60, 160 are prismatic and extend along the entire length of the slat 20 to seal off the gap between the adjacent slats 20. In this embodiment the first seal 60 or the second seal 160 is made of a plastic, in particular a rigid plastic, having a rigidity which is less than the rigidity of the material of the slat 20. The seal 160 is for example made of polyvinyl chloride (PVC) , polyamide (PA) or polyethylene (PE) or plastics having equivalent properties, or combinations thereof.

Alternatively, the first seal 60 or second seal 160 is made of a flexible, rubber-like material. Figure 4A shows the first seal 60 in its operational state in more detail. Figures 4B and 5 show the first seal 60 in its relieved state, when the adjacent slats 20 are notionally positioned spaced further apart from each other. The first seal 60 comprises a base body 61 that is confined behind the locking edges 47, an upper leg 80 that projects obliquely upwards with respect to the base body 61, and a lower leg 100 that projects obliquely downwards with respect to the base body 61.

The base body 61 comprises a straight neck 62 that fits loosely between the locking edges 47, and a wider head 63 that is locked in the confinement section 48. The head 63 comprises a lower locking body 64 and an upper locking body 65 that project mutually oppositely outward from the neck 62. The head 63 comprises at the lower locking body 64 a straight lower front surface 66 and at the upper locking body 65 a straight upper front surface 67 that both face the locking edges 47. As shown with the notional vertical line Q that extends perpendicular to the neck 62, the lower front surface 66 and the upper front surface 67 extend parallel to each other while the upper front surface 67 is staggered forwards with respect to the lower front surface 66 towards the nearest locking edge 47. The staggered distance is 10-50% of the entire thickness W of the head in that direction.

The head 63 comprises a straight bottom surface 68 and a straight top surface 69 that extend parallel to each other and parallel to the neck 62. The head 63 comprises a straight lower back surface 70 that merges via an oblique straight transitional surface 71 into a straight upper back surface 72. As shown with the notional vertical line R that extends perpendicular to the neck 62, the lower back surface 70 and the upper back surface 72 extend parallel to each other while the upper back surface 72 is staggered forwards with respect to the lower back surface 70 towards the nearest locking edge 47. The staggered distance is 10-50% of the entire thickness W of the head in that direction. The mutually staggered lower locking body 64 and upper locking body 65 have the same width W. In the operative state as shown in figure 4A, the lower locking body 64 is in abutment with the back surface 52 of the locking chamber 45 while the upper locking body 63 extends spaced apart therefrom, and the upper locking body 63 is in abutment with the nearest locking edge 47. The lower locking body 64 is supported by the bottom surface 50 or the neck 61 is supported by the lower locking edge 47. Inside the locking chamber 45 the base body 61 is thus engaged on diagonally opposite spots, which results in a bias of the neck in an upwardly rotating sense S with respect to the center of the opposite locking edges 47. This bias may even increase during the life time of the seal 60 or slat due to debris accumulation inside the locking chamber 45 that will wedge between the lower locking body 64 and the back surface 52. Despite this accumulated debris, it remains possible to pull the first seal 60 out of the locking chamber 45 in its elongate direction when it needs to be replaced, as the clearance between the upper locking body 63 and the back surface 52 remains present during the life time.

The upper leg 80 comprises in series as from the base body 11 a first compression section 81 that thickens or in cross section widens in the direction towards the distal end and that merges into a second compression section 82 that narrows or in cross section tapers towards the distal end. At the merger between the first compression section 81 and the second compression section 82 the upper leg 80 has it largest thickness V, and therefore the upper leg 80 has its highest stiffness there. The distal end forms an engagement section 88 with a sealing tip 84 at its end. The upper leg 80 comprises a straight front surface 83 that extends over the first compression section 81, the second compression section 82 and the engagement section 88. The front surface 83 merges via the sealing tip 84 into a first back surface 85. The compression section 82 furthermore comprises a straight first engagement surface 86 that in its operational state extends parallel to the support surface section 42. The first engagement surface 86 engages with at least 80%, preferably with at least 90%, and in this embodiment with 100% of its surface the support surface section 42. In the shown cross section, the largest width Ll of the first engagement section 86 is at least 20%, preferably at least 40% of the largest thickness V of the upper leg 80. The first engagement surface 86 merges into a second straight engagement surface 87 of the second compression section 81 that in its operational state extends parallel to the first left outer surface section 41 of the left sidewall 40. The second engagement surface 87 engages with at least 80%, preferably with at least 90%, and in this embodiment with 100% of its surface the first left outer surface section 41. In the shown cross section, the largest width L2 of the first engagement section 86 is at least 20%, preferably at least 40% of the largest thickness V of the upper leg 80. The first seal 60 may comprise a reducing blind slot 89 at the bottom of the first compression section 81 to form a living hinge 90 between the upper leg 80 and the base body 61.

The shape of the upper leg 80 is in conformity with the shape of the slat 20 along the first engagement surface 86 and the second engagement surface 87. These engagements ensures a tight sealing between the first seal 60 and the slat 20 into which it is inserted. Moreover, due to the large contact surface, the orientation of the sealing tip 84 remains constant under varying pressures that are exerted by the adjacent slat 20 against the sealing tip 84. The compression sections 81, 82 are biased to keep both the sealing tip 84 and the engagement surfaces 86, 87 in sealing engagement even when the gap between adjacent slats 20 varies, for example due to wear or due to a slight local bend or curvature in the mutually sliding slats 20. This tight sealing prevents the passage of cargo particles or dirt from the top surface 21 between the adjacent slats. The angle W of the support surface 42 ensures that the bias of the compression sections 81, 82 is converted into a substantial horizontal pressure force of the sealing tip 84 against the adjacent slat 20.

The lower leg 100 comprises a straight front surface 83 that merges via a curved sealing surface 103 at the distal end into a straight back surface 102. The sealing surface 103 is in sealing contact with the adjacent slat 20. This sealing prevents passage of upwardly spraying water or dirt, for example from the road, between the adjacent slats 20. In vertical direction in the shown cross section, the lower back surface 70 is located in about the middle of the contacting sealing tip 84 and the contacting spot of the sealing surface 103, whereby both are kept tightly against the adjacent slat.

Figures 6-8 show the second seal 160 in more detail. The parts thereof that correspond with the parts of the first seal 60 are provided with the same reference numbers. Hereafter only the distinguishing features are described in detail.

The second seal 160 comprises the first engagement surface 86 that merges into a second straight back surface 187 that extends along the first compression section 81 while it is spaced apart therefrom. A thereby formed clearance 49 between the first compression section 81 and the slat 20 to which the seal 60 is mounted ensures that the upper leg 80 remains movable, compressible and extendable with respect to the base body 61 even when the adjacent slats 20 are fully abutting each other or when some dirt has penetrated between the support surface section 42 and the engagement surface 86.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.