Abstract:
The invention relates to an accumulating conveyor, in particular for use in the motor vehicle industry, for example for conveying body parts on pallets. The pallets are automatically coupled in a form-fitting manner at the reversing station or at the reversing stations by at least one centering pin, wherein, after the relevant reversing station has been passed, the centering pin or the centering pins is or are automatically released again.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an accumulating conveyor, in particular for use in the motor vehicle industry, for example for conveying body parts. 
     2. Description of the Related Art 
     Accumulating conveyors are known. They generally consist of a motor-driven bottom strand and top strand which are used to convey pallets which serve to receive workpieces, for example sheet-like parts from body manufacturing, and from or else to which components can be removed or can also be supplied, for example manually, or else also by a robot arm. The strands of accumulating conveyors of this type move in two planes which are arranged one above the other and are generally horizontal, and run endlessly via reversing stations arranged at a distance from one another. 
     The invention is based on the problem of inventively refining an accumulating conveyor of the required type in such a manner that even heavier pallets are easily driven in a slip-free manner in the region of the reversing stations using structurally simple means. 
     The problem on which the invention is based is solved by an accumulating conveyor, in particular for use in the motor vehicle industry, for example for conveying body parts on pallets, comprising a flexible tension element which is driven, for example continuously, by motor, for example a chain or a belt which is guided in the region of the reversing stations via gear elements arranged on one shaft each, for example one drive wheel in each case, wherein the tension element is coupled to the relevant pallet by a device which can be actuated by a frictional connection, wherein the relevant shaft of the reversing station is assigned one driver wheel on either side of the shaft, said driver wheel having numerous recesses which are in each case arranged at preferably uniform angular distances from one another over the circumference of said driver wheel and in which a centering pin which is loaded by a compression spring is in each case arranged in a longitudinally displaceable manner, wherein, during the driving of the pallets from the top strand to the bottom strand and from the bottom strand to the top strand of the flexible tension element, in each case at least one centering pin of each driver wheel of the relevant shaft automatically engage in a form-fitting manner in recesses arranged on the underside of the relevant pallet and, after the relevant reversing station has been passed, also automatically slide out of said recesses again. 
     In the case of the invention, in the region of the loading and unloading station, even heavy pallets are conveyed in a slip-free manner from the top strand to the bottom strand and from the bottom strand to the top strand in a form-fitting manner via the centering pins and the driver wheels provided here. The centering pins engage automatically in recesses provided therefor on the underside of the relevant pallet and, at the bottom strand or top strand, also automatically come free again from said recesses after the pallet has been conveyed through the relevant reversing station by the tension element—chain or belt—which is driven, for example, continuously. Therefore, even heavy and loaded pallets are conveyed in a secure and slip-free manner through the reversing stations. 
     A possible embodiment of an accumulating conveyor arrange the recesses for the centering pins radially with respect to the center point of rotation of the relevant shaft, and therefore to the center point of rotation of the associated driver wheel. The centering pins can thereby be arranged in such a manner that, for example, of each driver wheel at the associated reversing station, for example in each case a plurality of centering pins, in particular two centering pins, grasp the relevant pallet in each case in a form-fitting manner. 
     A possible embodiment of an accumulating conveyor may couple the centering pins to the coupling recesses of a pallet over an angle of rotation range of approximately 180 degrees. 
     In a possible embodiment the pallets may be still coupled in the region of their horizontal in the region of the top strand as far as the horizontal region in the bottom strand to the driver wheels by the centering pins in a radially resilient and form-fitting manner. As a result, a secure and form-fitting connection or coupling to the pallets to be conveyed is produced virtually over the entire region of a reversing station. 
     A possible embodiment of an accumulating conveyor may have a braking device arranged next to the relevant driver wheel, said braking device braking the speed of the relevant pallet to zero or to the creep speed. This means that each reversing station has two braking devices of this type, and therefore even pallets conveyed up rapidly can be braked in order to ensure reliable entry of the centering pins into the cutout on the underside of the relevant pallet. For this purpose, for example, said cutouts on the underside can be elongated in the conveying direction or provided with run-on slopes. 
     A possible embodiment of the accumulating conveyor may be configured in such a manner that the pallets are forcibly guided on both sides of the accumulating conveyor in rails by means of guide rollers. Said rails can be, for example, of U-shaped design. 
     In a preferred embodiment, each reversing station has a drive wheel, wherein the underside of each pallet has two spaced-apart, central pallet pinions which are subjected to optionally adjustable friction force by brake pins, wherein the frictional connection to the tension element, which is optionally driven continuously, is overcome when the pallet comes to a standstill or the drive speed thereof is decelerated by means of a stopping device or by means of the braking device in the region of the reversing station. The flexible tension element may proceed continuously when the pallets are piled up or braked. 
     According to the invention, the underside of each pallet has, on opposite sides, at least one braking roller interacting with each braking device arranged here. A tilt-free braking to a standstill or into the creep speed of the relevant pallet is thereby brought about. 
     A possible embodiment of the accumulating conveyor may have an asynchronous drive motor for driving the flexible tension element, the rotational speed of which is regulable. 
     An embodiment of the accumulating conveyer may comprise an asynchronous motor driving the flexible tension element only in one conveying direction. 
     A possible embodiment of the accumulating conveyor may be advantageously assigned at least one stopping device. 
     Said stopping device can be used to stop the pallets in the conveying region such that the following pallets can catch up. The activation of a stopping device of this type can be incorporated into an SPC. The conveyor may also be assigned more than one stopping conveyor. Stopping conveyors of this type may be in addition to the braking devices at the particular reversing station or the reversing stations. 
     The invention is illustrated—partially schematically—with reference to an exemplary embodiment in the drawing, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of an accumulating conveyor; 
         FIG. 2  shows a top view of  FIG. 1 ; 
         FIG. 3  shows a section along line of  FIG. 1 ; 
         FIG. 4  shows a detail of a reversing station of  FIG. 1 , illustrated partially broken off and partially in section, and 
         FIG. 5  shows a further detail of the reversing station which can be seen in  FIG. 4  together with braking rollers and a brake disk and three pallets in various conveying positions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An accumulating conveyor which has a top strand  2  and a bottom strand  3  is denoted overall in the drawing by the reference number  1 . In the drawing, the direction of movement is indicated by the arrow  4 . The accumulating conveyor  1  is driven via a drive motor  5 , for example the rotational speed of which is regulable and is formed, for example, as an asynchronous motor. A centrally arranged, flexible tension element, for example a chain or a belt which is driven continuously by the drive motor  5 , is denoted by the reference number  6 . 
     The reference number  7  denotes a pinion, while  8  and  9  are shafts. The shafts  8  and  9  are mounted with little friction on both sides in bearings  10 ,  11  and  12 ,  13 , for example in ball bearings. In the end region on both sides, each shaft  8  or  9  bears one driver wheel  14 ,  15  or  16 ,  17  in each case. Each driver wheel  14 - 17  has recesses which are arranged at uniform angular distances from one another over the circumference of said driver wheel, are in the form, for example, of bores and of which only the recesses  18 ,  19 ,  20 ,  21 ,  22  and  23  are illustrated in  FIG. 4 . In the embodiment illustrated, all of the driver wheels  14  to  17  are designed with an identical shape and have, for example, the same number of recesses  18 - 23  but, if the need arises, can also be designed differently, for example can have a smaller or greater number of recesses than illustrated. 
     In  FIGS. 4 and 5 , the reference numbers  24 ,  25 ,  26  denote three pallets in different transportation positions while  27  relates to a braking device with a braking arm which is illustrated in  FIGS. 4 and 5  as an angle lever which is arranged so as to be able to swing about an axis  28 . A braking roller assigned to the relevant pallet  24  is denoted by  29  while, at  30 , a guide roller is arranged on the pallet  24 . The braking roller  29 , upon running onto a slope  31 , presses the braking device  27  downwards counter to the resetting force of a spring element  32  and thereby decelerates the movement of the pallet  24  in the movement thereof in the direction of the arrow  4  to a standstill or to a type of creep speed. Each of the driver wheels  14  to  17  can be assigned to one braking device  27  of this type, with which braking devices braking rollers  29  in each case interact. On each side at one or at both reversing stations, a braking device  27  of this type with a braking roller  29 , spring element  32  and axis  28  is in each case arranged on opposite sides in order to avoid tilting of the pallets, or guide rollers  30  which run in rails  52  are arranged on both sides of the pallets. 
     The driver wheels  14  to  17  are in each case assigned protective devices  33  and  34  which, as covering plates, cover the relevant driver wheels  14  to  17  outwards at a distance. 
     The reference numbers  35 ,  36  denote braking pins which are spring-loaded and which bring about a frictional connection with the pallet pinions  37  or the like, which are assigned to the relevant pallet  24 , by means of friction. Each pallet  24 - 26  has a device of this type. The springs press the braking pins  35  and  36  against corresponding friction surfaces of the pallet pinions  37  in the manner of a friction brake and thus produce a frictional connection. When the tension element  6  exceeds the drive force, the friction is overcome, and therefore the relevant pallet can be decoupled from the tension element  6  or the like and piled up. 
     A compression spring element  40 ,  41 ,  42 ,  43 ,  44  and  45  which in each case loads a centering pin  46 ,  47 ,  48 ,  49 ,  50  and  51  radially outwards is in each case arranged in the recesses  18  to  23 . The centering pins  46  to  51  are arranged at a uniform angular distance in the recesses  18  to  23 , which are directed radially with respect to the center point of the shaft  8 . All of the other driver wheels  14  to  17  which are not visible in the drawing are configured in the same manner. The number of centering pins can be greater or smaller than illustrated in the drawing. It is also conceivable to assign a different number of centering pins with corresponding compression spring elements  40  to  45  or the like to the individual driver wheels  14  to  17 . 
     The guide rollers of each pallet, which guide rollers are arranged on both sides of each pallet, are in each case forcibly guided in U-shaped rails  52 ,  53 . 
     The underside of each pallet has, on opposite sides, a plurality of coupling openings in which, on opposite sides of each pallet, at least in each case one centering pin, but preferably in each case two centering pins, engage in a form-fitting manner during circulation through a reversing station and convey the pallet in a tilt-free and jerk-free manner from the top strand  2  to the bottom strand  3  and from the bottom strand  3  to the top strand  2 . 
     The reference number  54  denotes a stopping device by means of which the pallets are stopped when required. A plurality of stopping devices of this type can be provided over the conveying path of the accumulating conveyor  1 , when required. The manner of operation, in particular the control thereof, is incorporated into a stored program control (SPC). If a pallet is released by the stopping device  54 , the pallet is conveyed further in the conveying direction  4  and is stopped again, or the conveying speed thereof is decelerated to the creep speed, in the region of the relevant reversing station such that the centering pins  46 - 51  can engage in a form-fitting manner in the corresponding openings on the underside of the particular pallet without disturbance. 
     The manner of action is as follows: 
     The embodiment illustrated substantially has the task of conveying the pallets  24  from the top strand  2  to the bottom strand  3  or from the bottom strand  3  to the top strand  2  without disturbance. 
     The shaft  8 , which is driven continuously by the central pinion  7  at the relevant reversing station via the chain  6  or a belt also conveys the pallet  24  et seq. In each case two of the driver wheels  14  to  17  are arranged at an axial distance from each other on the same shaft  8  or  9 . In the embodiment illustrated, each driver wheel  14 ,  15  or  16 ,  17  has six centering pins  46 ,  47 ,  48 ,  49 ,  50  and  51  which, for example in each case two, engage in a form-fitting manner in the matching receiving openings and therefore reliably convey the relevant pallet  24  in the region of the relevant reversing station. The pallet  24  moves in a forcibly guided manner through the rail-like profiles  52  and  53 , and the flexible tension means, in particular a chain  6 , drives the pallets  24 - 26  by means of the central pallet pinions  37  which are subjected by spring elements to the controlled or adjustable frictional driver force of the braking pins  35  and  36 . When a pallet  24  arrives at the stopping device  54 , the pallet pinions  37  begin to rotate freely corresponding to the speed of the drive chain  6 . The pallet  24  stops. During the continued movement, the pallet  24  or the like is carried along by a form-fitting connection (latching) by, for example, in each case two centering pins on opposite sides of the two driver wheels  14 ,  15  of the relevant reversing station. As a result, slipping of the pallets  24  is impossible. 
     The features described in the patent claims and in the description and also apparent from the drawing can be essential both individually and also in any combinations for implementing the invention. 
     REFERENCE NUMBERS 
     
         
           1  Accumulating conveyor 
           2  Top strand 
           3  Bottom strand 
           4  Direction of movement 
           5  Drive motor 
           6  Tension element, flexible 
           7  Pinion 
           8  Shaft 
           9  Shaft 
           10  Bearing 
           11  Bearing 
           12  Bearing 
           13  Bearing 
           14  Driver wheel 
           15  Driver wheel 
           16  Driver wheel 
           17  Driver wheel 
           18  Recesses 
           19  Recesses 
           20  Recesses 
           21  Recesses 
           22  Recesses 
           23  Recesses 
           24  Pallet 
           25  Pallet 
           26  Pallet 
           27  Braking device, braking arm 
           28  Axis 
           29  Braking roller 
           30  Guide roller 
           31  Slope 
           32  Spring element 
           33  Protective device 
           34  Protective device 
           35  Braking pin, frictional connection device 
           36  Braking pin, frictional connection device 
           37  Pallet pinion 
         
           38 
         
         
           39 
         
           40  Compression spring element 
           41  Compression spring element 
           42  Compression spring element 
           43  Compression spring element 
           44  Compression spring element 
           45  Compression spring element 
           46  Centering pin 
           47  Centering pin 
           48  Centering pin 
           49  Centering pin 
           50  Centering pin 
           51  Centering pin 
           52  Rail, forced guidance 
           53  Rail, forced guidance 
           54  Stopping device