Patent Publication Number: US-6220183-B1

Title: Stackable pallet

Description:
FIELD OF THE INVENTION 
     The present invention relates to a stackable pallet for forming a work or storage stack. 
     DESCRIPTION OF THE PRIOR ART 
     EP 0 725 027 A2 describes a pallet for depositing sheets on a stack. The pallets used in this connection are provided with support elements. These support elements are designed in such a way that selectively a storage stack of pallets or stack boards, which are stacked on top of each other with a first, small spacing between them, or a work stack of pallets or stack boards, which are stacked on top of each other with a second, larger spacing between, is formed. 
     DE 92 17 413 U1 describes a stackable packaging unit, wherein the pallets can be selectively stacked on top of each other with or without a space between them. 
     U.S. Pat. No. 3,641,949 discloses pallets which can be stacked on top of each other with a first spacing between them. By pivoting or rotating, the pallets, it is possible to stack them on top of each other at a second spacing from each other, wherein this second space is used for inserting the fork of a fork lift, but not for receiving material to be stacked. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a stackable pallet. 
     This object is attained in accordance with the present invention by the provision of a stackable pallet that has both a support plate and feet. The feet are arranged so that the pallets can be stacked on top of each other as a storage stack, and also as a work stack. The feet of each pallet telescope inside the feet of adjacent pallets for forming the storage stack. In the work stack arrangement, the feet on an upper pallet, which are provided with a base of their upper end and a resting place at their upper end, are received in the resting place of the feet of the pallet below. 
     The advantages which can be achieved by means of the present invention lie, in particular, in that it is possible to selectively form a work or a storage stack from the same group of pallets. In this case, the feet of the pallets, which are stacked on top of each other, both in the arrangement of the pallet in the work stack as well as the storage stack, are placed flush above each other in the vertical direction. Thus, occurring weights are transmitted in the vertical direction from the feet of the pallets on the top directly to the feet of pallets located under them. In this way, the transfer of the weight from a pallet to the pallet located underneath it takes place without the appearance of bending forces, by means of which bending of the pallets is reduced. A support plate of the pallet only needs to absorb the weight of the material stored on the support plate. Because of this optimized path of the forces, it is possible to make the pallets of the appropriate size, which considerably reduces the production costs and material costs. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The present pallet in accordance with the invention is represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
     FIG. 1, a schematic view from above on a pallet in a first preferred embodiment, 
     FIG. 2, a schematic lateral view of the pallet in FIG. 1, 
     FIG. 3, a schematic sectional view through a work stack with three pallets stacked on top of each other, 
     FIG. 4, a schematic sectional view through a storage stack with three pallets stacked on top of each other, 
     FIG. 5, a schematic enlarged view from above on a foot of a pallet, and in 
     FIG. 6, a schematic view from above on a pallet in a second preferred embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A stackable pallet as seen generally at  1  in FIG. 1, is preferably used as a stack board for depositing sheets for forming a stack. For example, this pallet  1  can be placed into a delivery device of a sheet processing machine. A plurality of these pallets  1  or stack boards are used in a raising and lowering device of the delivery device in connection with sheet-printing machines for printing securities in particular. 
     Such a pallet  1  has a support plate  2 , which is designed to be essentially rectangular. Thus, in the present preferred embodiment, this support plate  2  has four lateral faces. Two longitudinal lateral faces or side edges  3 ,  4  lie parallel with each other and are perpendicular in relation to the two transverse lateral faces or sides edges  6 ,  7 . Feet  9 ,  11 ,  12 ,  13  are fastened in or on the support plate  2  in the area of its corners, and these feet project out of an underside  8  of the support plate  8 , as seen in FIG. 2. A first straight sectional line  19 , and a second straight sectional line  21  are determined by centers  14 ,  17 , or respectively  16 ,  18  of feet  9 ,  12 , or respectively  11 ,  13 , of a respective pair, which are located diagonally opposite each other. An intersection of these two straight sectional lines  19 ,  21  determines the origin of a pivot axis  22 , which normally lies on a plane formed by the support plate  2 , all as shown in FIG.  1 . This pivot axis  22  and the centers  14 ,  17 , or respectively  16 ,  18 , of the feet  9 ,  12 , or respectively  11 ,  13 , of a respective pair each determine a straight line  52 ,  53 ,  54 ,  56 , wherein a respective distance a 9 , a 11 , a 12 , a 13  between the pivot axis  22  and the centers  14 ,  16 ,  17 ,  18  is of the same length, again as seen in FIG.  1 . The straight lines  52 ,  54 , or respectively  53 ,  56 , of a pair enclose an opening angle  5 , for example 180°. In this way, by pivoting the pallet  1  around a pivot angle, for example 180°, the centers  14 ,  17 , or respectively  16 ,  18 , of the feet  9 ,  12 , or respectively  11 ,  13 , of a pair change their positions, i.e. in place of the first foot  9 , or respectively  11 , of a pair, now the associated second foot  12 , or respectively  13 , of the pair is in the position of the first foot  9 , or respectively  11 . The opening angle  5  of the straight lines  52 ,  54 , or respectively  53 ,  56 , of a pair and the pivot angle are of the same size. 
     The feet  9 ,  11 ,  12 ,  13  are hollow, and in the present embodiments are designed in plan view in the shape of an elongated hole with rounded edges, as shown most clearly in FIG.  5 . The feet  9 ,  11 ,  12 ,  13  are designed to be conical, i.e. to extend tapering, from their upper end  23  to their lower end  24 , as seen in FIGS. 3 and 4. The bottom  25  of the lower end  24  of each foot  9 ,  11 ,  12 ,  13  is closed and is provided with a base  26 . The upper end  23  is open and is provided with a circular flange  27  for supporting or fastening the feet  9 ,  11 ,  12 ,  13  in, or respectively on, the support plate  2 . The support plate  2  for each foot  9 ,  11 ,  12 ,  13  is provided with a bore  28 , in which the flange  27  is supported or fastened. This flange  27  has a collar  29 , which is used to increase the load-bearing capacity and which is molded into the support plate  2  which, in the present example, is made of plastic. In the area of the foot upper end  23 , the inside of the flange  27  is provided with a depression  31  which is embodied as a resting place. This depression  31  is used as a centering element for feet  9 ,  11 ,  12 ,  13  stacked on top of each other. A depression base surface  32 , i.e. a resting place of this depression  31  is matched to the base  26  of the lower end  24  of the foot  9 ,  11 ,  12 ,  13 . The base surface  32  is interrupted by the foot  9 ,  11 ,  12 ,  13  so that, strictly speaking, two partial depression base surfaces  32  are provided for each foot. For the sake of simplicity, however, the two partial surfaces and their virtual extension are understood to be the base surface  32  in what follows, so that this base surface  32  in the flange  27  corresponds in shape and size approximately to the base  26  at the lower end  24  of the foot  9 ,  11 ,  12 ,  13 , all as seen in FIGS. 3,  4  and  5 . A longitudinal axis  34  of this base surface  32  in the shape of an elongated hole, and a longitudinal axis  33  of the plan view in the shape of an elongated hole of the foot  9 ,  11 ,  12 ,  13  enclose an opening angle a of, for example, 90°. An inclined, circumferential lateral surface  36  which, for example, encloses an opening angle B of 135°, leads from a top of the flange  27  to this base surface  32 . 
     A hollow interior  30  of the respective foot  9 ,  11 ,  12 ,  13  is matched to the associated exterior contour, so that the feet  9 ,  11 ,  12 ,  13  can be pushed into each other when the pallets are in there storage stack orientation, as shown in FIG.  4 . 
     A pair of diagonally opposed feet  9 ,  12 , or respectively  11 ,  13 , lying on a straight sectional line  19 ,  21 , are respectively arranged in such a way, that the centers  14 ,  17 , or respectively  16 ,  18 , of both feet  9 ,  12 , or respectively  11 ,  13 , have the same distance a 9 , a 12 , or respectively a 11 , a 13 , from the pivot axis  22 , and the extensions of the longitudinal axes  33  of both feet  9 ,  12 , or respectively  11 ,  13 , enclose an angle r of 90° in respect to each other. 
     In the first preferred embodiment, respectively one longitudinal axis  33  of a foot  11 ,  12  extends parallel with a longitudinal lateral face  3 ,  4 , and the longitudinal axis  33  of the corresponding foot  9 ,  13  of a pair of digonally opposed feet  9 ,  12 , or respectively  11 ,  13 , extends perpendicularly in respect to this, first longitudinal axis i.e. parallel with a transverse lateral face  6 ,  7 . 
     In a second preferred embodiment of a pallet  42 , as seen in FIG. 6, feet  37 ,  38 ,  39 ,  41  are used, which are like the feet  9 ,  11 ,  12 ,  13  in the first preferred embodiment. Here, the longitudinal axes  33  of all of the feet  37 ,  38 ,  39 ,  41  are arranged at an angle of 45° in relation to the longitudinal and transverse lateral faces of the pallet  42 . The longitudinal axis  33  of a first foot  37 , or respectively  39 , of a pair of diagonally opposed feet  37 ,  39 , or respectively  38 ,  41 , extends perpendicularly in respect to a line which halves the angle of the associated longitudinal and transverse lateral faces, i.e. approximately perpendicularly in respect to the associated straight sectional line  43 , or respectively  44 . The longitudinal axis  33  of a corresponding second foot  39 , or respectively  41 , of the pair extends parallel with a line which halves the angle of the associated longitudinal and transverse lateral faces, i.e. approximately parallel in respect to the associated straight sectional line  43 , or respectively  44 . 
     To form a storage stack  46 , of pallets, as shown in FIG. 4 pallets  1 ,  47 ,  48  are aligned in the same way and are stacked on top of each other, i.e. the feet  9 ,  11 ,  12 ,  13  of an upper pallet  1  are pushed into or telescope into the corresponding hollow feet  9 ,  11 ,  12 ,  13  of the pallets  47 ,  48  located below. Spacers, not represented, have been attached to the pallets  1 ,  47 ,  48 . This results in a first minimum distance a 46  between the support plates  2  of the pallets  1 ,  47 ,  48 . These pallets  1 ,  47 ,  48  can also rest directly on each other, so that there is no distance a 46 . 
     If it is now intended to form a self-supporting work stack  49 , or pallets, as shown in FIG. 3 pallets  1 ,  47 ,  48 , which are stacked on top of each others, are alternatingly turned by 180° around the pivot axis  22 . With this arrangement, the longitudinal axes  33  of feet  9 ,  11 ,  12 ,  13  arranged on top of each other are alternatingly turned by 90° in respect to a vertical axis  51  formed through the centers  14 ,  16 ,  17 ,  18  of the feet  9 ,  11 ,  12 ,  13 . This vertical axis  51  extending through the centers  14 ,  16 ,  17 ,  18  of the feet  9 ,  11 ,  12 ,  13  is the same, i.e. is fixed in place, in the work stack  49 , as well as in the storage stack  46 . 
     The feet  9 ,  11 ,  12 ,  13  of the pallets  1 ,  47 ,  48  transfer the weight of the pallets  1 , or respectively,  47 , directly in the vertical direction to the feet  9 ,  11 ,  12 ,  13  of pallets  47 , or respectively  48  located below them. 
     To form a work stack  49  from a storage stack  46 , the required pivot angle is a function of the arrangement of the feet  9 ,  11 ,  12 ,  13 . For example, with an arrangement of the feet  9 ,  11 ,  12 ,  13  in the shape of a square, a pivot angle of only 90° is required for forming work stacks and storage stacks  49 ,  46  which are differently distanced. 
     If an uneven number of feet is provided, all feet must be at the same distance from the pivot axis. Straight connecting lines between the center of the feet and the pivot axis respectively enclose opening angles of the same size. Thus, the feet are arranged at the same graduation angle on a graduated circle around the pivot axis. In this case, a pivot angle equals the opening angle, or corresponds to a whole-number multiple of the opening angle. 
     The shape of the feet  9 ,  11 ,  12 ,  13  can also be selected to be quite different. However, all shapes must have in common that for forming a storage stack  46  the feet  9 ,  11 ,  12 ,  13  are movable into each other, preferably slidable, or telescoping and for forming a work stack  49 . These feet  9 ,  11 ,  12 ,  13  rest on top of each other. In this case, the contact zones forming between the bases  26  and the base surfaces  32  of the feet resting on top of each other lie flush on top of each other along a vertical straight line. 
     Because of the pivoting of the pallet  1 ,  47 ,  48  for forming a work stack  49 , the feet  9 ,  11 ,  12 ,  13  in the preferred embodiments rest on top of each other in a position which is pivoted around their longitudinal axis  51 . 
     Because of this, the longitudinal axes  51  of the feet  9 ,  11 ,  12 ,  13  stacked on top of each other lie on a straight line, i.e. the feet  9 ,  11 ,  12 ,  13  lie directly on top of each other. 
     In place of pivoting the entire pallet  1 ,  47 ,  48 , it is also possible to respectively pivot or rotate the individual feet, and to stack the support plates on top of each other without pivoting of the support plate. 
     The cross section of feet lying on top of each other in a storage stack are approximately congruent. To form a work stack, the feet are stacked on top of each other by means of a pivot movement, for example of the entire pallet, or of individual feet, in such a way that the cross sections of feet lying on top of each other are not congruent and therefore can be placed on top of each other. 
     While preferred embodiments of a stackable pallet in accordance with the present invention have been set fully and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example the overall size of the pallets, the specific material used to form the pallets and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.