Patent Abstract:
An arrangement for coupling a pallet in a conveying device includes a pallet having wheels and forming a part of a transport track of the conveying device, and a drive element. A coupling piece is adapted to be connected to the pallet and a fastening parties connects the drive element to the coupling piece.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of International Application No. PCT/FI2005/000007 filed Jan. 5, 2005, designating the United States and claiming priority from application Ser. No. FI20040157 filed in Finland on Feb. 2, 2004, the disclosures of both foregoing applications being incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to an arrangement for coupling pallets of a travelator or equivalent.  
         [0003]     Like escalators, travelators are conveying devices used to move people and goods. They differ from escalators e.g. in that they often work in a substantially horizontal position or in a position slightly inclined relative to their direction of motion, so that successive steps, i.e. pallets, form a substantially even and rectilinear transport track instead of stair-like steps as in escalators. Travelators are also referred to as moving sidewalks and autowalks.  
         [0004]     In known travelators, autoramps and escalators, the pallets or steps are typically connected to an endless chain, belt or equivalent serving as a drive element by means of a separate coupling element. In known solutions, the coupling arrangements are complicated and often also require the use of special tools for the coupling to be successfully performed in the desired manner. Long travelators contain a large number of pallets, each one of which has to be coupled to the drive element either by one end or by both ends. These known coupling solutions and the associated adjustments are slow and complicated to implement, which is why the installation times are very long, especially when long travelators are to be installed. This is expensive and otherwise undesirable. In addition, maintenance and repair operations take a longer time because the release and re-mounting of known coupling elements is a slow process. Coupling elements of a larger size, which take up space around their path of motion and add to the weight of the structures present further problems. An additional problem in known coupling elements is the chain serving as a drive element, which has to be of a special construction due to the coupling. Such a chain, which is specific only to a given application, is generally expensive and may be difficult to obtain in urgent cases of repair.  
       SUMMARY OF THE INVENTION  
       [0005]     An object of the present invention is to overcome the above-mentioned drawbacks and to achieve an arrangement for coupling pallets of a travelator, moving ramp or escalator or an equivalent apparatus, an arrangement that is of economical cost and allows easy coupling, and wherein the pallet is coupled especially to a chain functioning as a drive element moving the pallets.  
         [0006]     The above and other objects are achieved according to the invention by the provision of an arrangement for coupling a pallet in a conveying device which in one exemplary embodiment includes: a pallet having wheels and forming a part of a transport track of the conveying device; a drive element; a coupling piece adapted to be connected to the pallet; and a fastening part connecting the drive element to the coupling piece.  
         [0007]     The advantages provided by the pallet coupling arrangement of the invention include easy and fast installation, which means that the installation, maintenance and repair times are short and consequently the downtimes are also short. In addition, the coupling solution is simple and reliable, so the coupling is safe and requires no special tools in order to be successfully carried out. A further advantage is that the drive elements used may consist of standard chains, which are economical and quickly available when needed. Yet another advantage is that the coupling element is of small size and light weight, so the coupling solution does not take up much space around its path and the coupling pieces do not strain the travelator structures by their weight. A significant advantage is that the pallet can be connected to the chain from above. Thus, the pallet can be easily fastened to the chain during installation, and during maintenance or repair the pallet can be easily released from the chain and secured to it again. In the further exemplary embodiments of the invention, the pallet can be lowered to its position relative to the chain and the pallet track and connected to the chain without lateral movement of the chain or the pallet lowered into position. As the connection is easy to make and release, installation and maintenance work requires less time.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     In the following, the invention will be described in detail with reference to an exemplary embodiment and the accompanying drawings, wherein:  
         [0009]      FIG. 1  shows an oblique top view of a typical pallet in which the coupling arrangement of the invention can be used;  
         [0010]      FIG. 2  shows a more detailed view of the pallet of  FIG. 1  as seen from the end of the pallet;  
         [0011]      FIG. 3  shows an oblique top view of the main components of the pallet coupling arrangement according to an exemplary embodiment of the invention;  
         [0012]      FIG. 4  shows a detail of a pallet coupling arrangement according to according to another exemplary embodiment of the invention in oblique top view;  
         [0013]      FIG. 5  shows an oblique top view of the main components of the pallet coupling arrangement of an exemplary embodiment of the invention in an assembled state; and  
         [0014]      FIG. 6  shows a top view of a pallet provided with a pallet coupling arrangement according to a further exemplary embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0015]     Referring to  FIG. 1 , there is shown a pallet structure  1  comprising a pallet body  3 , which has preferably been produced by extruding a suitable profile from aluminum or some other appropriate metal or metal alloy. During manufacture of the profile, a given profile is extruded in bars of a length suited for manufacture, transport or other purposes. Later during manufacture of the pallet, parts of a length exactly suited for the purpose are cut from these profiled bars. Thus, the same profile can easily be used for pallets of different lengths, which makes it easy to vary the width of the conveyor track of the travelator. Secured to the pallet body  3  are wheels  4  at each end of the pallet and likewise at least at one end a fastening element  20  (see for example  FIGS. 3 and 5 ), by which the pallet  1  is coupled to an endless chain, toothed belt, rope or equivalent actuating element serving to move the pallets. The fastening element  20  is secured e.g. to a mounting hole  5  ( FIGS. 1 and 2 ) provided at the end of the body  3 . The holes and other shapes provided in the body  3  for mounting the fastening elements and wheels may be profile shapes or separately made in the profile.  
         [0016]     As shown in  FIG. 2 , a surface part extruded from plastic or equivalent material is fastened onto the body  3  of the pallet  1  e.g. by snap-on couplings or corresponding shape-locked couplings. The surface part preferably consists of one or more surface plates  2   a - 2   c  ( FIG. 1 ) of suitable width, which are also provided with the necessary corrugations in the direction of the pallet track. Each surface plate  2   a - 2   c  is provided with snap-on coupling elements or corresponding coupling elements  6 , preferably in the lower part or on the lower surface of the surface plates, placed at suitable points, for example at the ends and in the middle part of the surface plates. The surface plates are thus firmly held in position on the pallet body  3  and can be easily pressed into position and also easily released from the body using a tool suited to the purpose. Correspondingly, placed at suitable points in the upper part of the pallet body  3  are counterparts  7  corresponding to the aforesaid coupling elements, so that the coupling elements  6  can be fastened to the counterparts in a shape-locked manner.  
         [0017]     The width of the surface plates  2   a - 2   c  is so defined that, using a suitable number of surface plates of the same width, it is possible to cover pallet bodies of different lengths, so the same parts can be used to assemble pallets of different lengths.  
         [0018]      FIGS. 1 and 2  show a pallet  1  provided with differently colored surface plates  2   a  and  2   b  and also transparent or translucent surface plates  2   c.  A notice, advertisement or other element varying the appearance, printed on paper, plastic or equivalent material may be placed under the transparent or translucent surface plates  2   c,  between the body  3  and the surface plate  2   c.  By illuminating such an element from below or from the side, various visual effects can be produced. The transparent or translucent surface plates  2   c  are preferably placed in the middle part of the pallet  1 . By disposing surface plates of different colors in different places in the longitudinal direction of the pallet  1 , the appearance of successive pallets may be varied. Thus, the appearance of the conveyor track of the travelator may be easily to changed.  
         [0019]     The body  3  of the pallet  1  consists of one or more profiled parts placed side by side. The body  3  is preferably composed of two body halves consisting of identical, mutually upside-down oriented profiled parts, which are also horizontally conversely arranged. Thus, the two halves of the body can be easily cut off the same profiled bar and turned into mutually opposite positions and joined together during assembly of the body.  
         [0020]      FIGS. 3-5  present a fastening element  20  used in the coupling arrangement of the invention, designed to connect the pallet to the chain  12  that moves the pallets. The fastening element  20  comprises at least a coupling piece  8 , a cylindrical shaft  9  fixedly secured to the coupling piece  8  and a locking element  13 , such as a spring. Two downwards-opening slots  10  are provided in the lower surface of the coupling piece  8 . The distance between the slots  10  corresponds to the distance between holes in the chain  12 . The slots  10  extend in the same direction as the shaft  9  which is transversely, i.e. perpendicularly, to the direction of motion of the pallets  1 . The width, height and radius of curvature at the upper edge of the slots  10  are designed so that two fastening pins  11  of a diameter corresponding to that of a normal chain pin can be inserted into the slots  10 , yet without making the slot-and-pin coupling too loose. Since there are chains of many widths, the fastening pins  11  used may be normal longer chain pins of a wider chain instead of separate fastening pins. In this case, the longer chain pins function as fastening pins  11 . Hereinafter, ‘fastening pins’  11  refers to both longer chain pins and fastening pins specially made for this purpose.  
         [0021]     The spring used as a locking element  13  is of a size and shape such that it can be locked onto the coupling piece  8  by spring force. The locking element  13  is a roughly U-shaped piece made from thin sheet metal, and it has in its bottom part two protrusions  14  whose size, orientation and mutual distance correspond to the size, orientation and mutual distance of the slots  10 . Moreover, the locking element  13  has at each upper edge an inward elbow  21 , which is fitted to meet the upper surface of the coupling piece  8  when the pallet is coupled to the chain.  
         [0022]      FIG. 4  presents a more detailed view of the counter-structure in the body part of the pallet  1  for coupling the fastening element  20  to the pallet  1 . The body  3  may be provided with a separate coupling piece  15  as shown in the figure, with a mounting hole  16  for the shaft  9  of the fastening element, or the body may be provided with a mounting hole  5  corresponding to hole  16  as mentioned above. In this case, no coupling piece  15  is needed. From the point of view of the invention, either solution will serve the same purpose. The mounting hole  5 ,  16 , which is located at the end of the pallet in the area between the wheels  4 , is provided with bushes  17  functioning as slide bearings so that, when mounted in the mounting hole  5 ,  16  through the bushes  17 , the outer end of the shaft  9  extends over the innermost bush  17 . This protruding outer end of the shaft is provided with a groove  22  whereby the shaft is locked in position in the axial direction by means of a circlip  18 . A further feature characteristic of the shaft  9  is that the shaft  9  extends in the same direction as the fastening pins  11  and substantially in the same plane with the axes of the fastening pins, preferably at an equal distance from the axes of the fastening pins.  
         [0023]     If the shaft  9  is locked directly to the mounting hole  5  going through the entire pallet, then the lower surface of the pallet body has to be provided with recesses  19  as shown in  FIG. 6  to allow the outermost bush  17  and the circlip  18  to be mounted in place. On the other hand, if a separate coupling piece  15  is used, then the pallet body has to be provided with a suitable space for this purpose.  
         [0024]      FIG. 5  presents the pallet coupling arrangement in an assembled state. The coupling piece  15  may represent a separate piece or also a part of the pallet body. At the coupling point, instead of normal chain pins, the chain  12  may be provided with longer fastening pins  11 , the other ends of which are inserted into the slots  10  in the lower surface of the coupling piece  8  so that the front surface of the coupling piece  8  is as close to the chain  12  as possible or in contact with the chain. With the fastening pins  11  in the slots  10 , the locking element  13  is set from below onto the coupling piece  8  so that the protrusions  14  in the bottom of the locking element  13  press the fastening pins  11  against the upper surface of the slots  10  and that the elbow  21  extending inwards at each upper edge of the locking element  13  meets the upper surface of the coupling piece  8 , pressing the locking element  13  tightly into position.  
         [0025]     The structure of the fastening element  20  may differ from that described above. For example the coupling piece  8  and the locking element  13  may be of some other type than in the above description. The fastening element  20  may be, for example, so constructed that the shaft  9  is not a fixed part of the coupling piece  8 , but instead the coupling piece  8  is provided with a hole which is used to fasten the coupling piece onto a locking shaft locking the two halves of the body  3  together. The end of the locking shaft extends far enough out of the central hole of the body  3  to allow the coupling piece to be locked onto the locking shaft, for example, by a circlip.  
         [0026]     The locking element corresponding to locking element  13  may also be a structure like that presented in  FIGS. 7 and 8 . In  FIG. 7 , the locking element is a plate  23  which is provided with a central hole substantially corresponding to the cross-sectional shape of the coupling piece  8  and which is placed on the shaft  9  at the mounting stage. After the fastening pins  11  have been mounted into the slots  10  from below, the fastening pins are locked in place by pulling the plate  23  onto the coupling piece, thus preventing them from falling out of the slots. The plate  23  may additionally have at the lower edge of its central hole small upwards acting spring-like parts (not shown) pressing the fastening pins  11  to the slots  10 . Such a structure provides the advantage of easy locking and release. In addition, for example, in connection with maintenance, the plate  23  will not be easily lost as it can be left on the shaft for the time of maintenance.  
         [0027]     In  FIG. 8 , the locking element is a spring  24  corresponding to locking element  13 . It has a construction that allows it to be pressed into position from above the coupling piece  8  in the direction of the arrow  25  to lock the fastening pins in the slots  10 . In  FIG. 8 , the spring  24  depicted with a broken line represents the position of the spring before the spring  24  is locked in position on the coupling piece. The size of the spring  24  is so designed in relation to the coupling piece  8  that, when mounted in the locking position, the free ends of the spring will press the fastening pins into the slots  10  while the spring is simultaneously pressed against the upper surface of the coupling piece  8 . The advantage of this embodiment is that it permits an easy and quick installation. A correctly designed spring  24  is easy to press onto the coupling piece  8 . Likewise, the spring can be easily removed by means of a suitable tool.  
         [0028]     Similarly, it is obvious that, instead of the use of locking elements  13 ,  23 ,  24 , the slots  10  may be holes and the ends of the fastening pins  11  projecting from the chain can be locked on the back surface of the coupling piece  8  by means of circlips. In this case, the lower surface of the back part of the coupling piece may be provided with recesses or equivalent to allow the circlips to be mounted from the below. The recesses allow the surface of the locking piece to be evenly set against the pallet body. Instead of circlips, the fastening pins  11  may have bolt-like heads with a diameter larger than the shank part of the pin. In this case, the fastening pins can be inserted into the holes of the coupling piece  8  from the side of the pallet, whereupon the chain  12  is fastened by its holes to the fastening pins. The holes of the coupling piece are in this case provided with countersinks on the back surface for the heads of the fastening pins.  
         [0029]     It is additionally possible that the coupling piece  8  has only one slot  10  or hole, in which is mounted only one fastening pin  11  or equivalent of a design such as a longer chain pin. This may be possible, for example, in light structures or if the chain  12  has thick pins in any case.  
         [0030]     Instead of a fastening pin/fastening pins  11 , the chain may also have another type of fastening part, for example, a chain link shaped to permit fastening or some other detent for engaging the coupling piece  8 . In the case of another type of fastening part, the coupling piece is correspondingly specifically designed as required by such a detent. For example, a tooth-like peg provided with a hole and jutting out laterally from the side plate of a chain link could be coupled in the fastening element by means of a bolt or a suitable cotter pin arrangement.  
         [0031]     It is likewise obvious that the shafts  9  may also function as locking shafts that lock the body structure composed of two separate profiled pieces together as a single assembly.  
         [0032]     It is further obvious that, instead of a chain as described above, it is possible to use different types of chain structures or equivalent as a drive element.  
         [0033]     It is further obvious to the person skilled in the art that the coupling piece  8  may be rigidly fastened relative to the link of the chain  12 , or that the fastening to the pallet is implemented between the joints/pins of the chain  12  at the link whereby the fastening to the chain  12  takes place.  
         [0034]     It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

Technology Classification (CPC): 1