Abstract:
An apparatus for forming groups of superposed, flat items, includes a conveyor having a transporting device traveling in a conveying direction along a generally horizontal working flight; and a plurality of upstanding pusher fingers secured to the transporting device. A plurality of storage chutes are serially positioned above the working flight for holding items in a superposed stack therein. An item-retaining device is situated at a lower, item-discharging end of each chute. The item-retaining device includes a component defining an item-retaining surface for retaining the items in the chute by supporting a lowermost item of the stack. Each pusher finger is arranged for travel through the item-discharging end for pushing all items forming part of the stack in the chute and being situated in a path of travel of the pusher finger, off the item-retaining device and for advancing the items in the conveying direction along the working flight. A height-adjusting device sets the component into different selected positions for changing a vertical distance of the item-retaining surface from the working flight to vary a number of items forming part of the stack in the chute and being situated in the path of travel of the pusher fingers.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of International Application PCT/CH96/00423 filed Dec. 2, 1996. 
    
    
     This application claims the priority of Swiss Application 3557/95 filed Dec. 15, 1995 which is incorporated herewith by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus for forming groups of superposed flat items, such as disk-shaped confectionary products. The apparatus has a conveyor which carries projecting fingers to push the item groups, while they are being formed, along an upper, approximately horizontal working flight in a conveying direction. Above the working flight a plurality of serially arranged chutes are provided each accommodating a stack of superposed items and each having a lower, item-discharging opening above the working flight, at a distance therefrom. The fingers are adapted to push simultaneously a plurality of items out of the lower end of the chutes. 
     An apparatus of the above-outlined type is described in British Patent 1,001,036. A circulating conveyor chain carries pusher fingers at uniform distances which project upwardly from the chain along a horizontal working flight. Above the working flight two chutes are arranged in series, containing stacks of superposed flat items. The bottom of each chute is situated above and spaced from the chain and is closed by a slotted base while being open at the lower end in the conveying direction. As the fingers travel with the circulating chain, they project through the slot of the base plate and push the lowest item out of the chute. The item removed in this manner from the first chute is pushed through underneath the base plate of the second chute so that the item moved out from the second chute will be superposed on the item originating from the first chute. Subsequently two of such item groups are packed together. Such an apparatus has been found to be satisfactory but has the disadvantage that its versatility is limited. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an apparatus of the above-outlined type which has a substantial adaptability. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the apparatus for forming groups of superposed, flat items, includes a conveyor having a transporting device traveling in a conveying direction along a generally horizontal working flight; and a plurality of upstanding pusher fingers secured to the transporting device. A plurality of storage chutes are serially positioned above the working flight for holding items in a superposed stack therein. An item-retaining device is situated at a lower, item-discharging end of each chute. The item-retaining device includes a component defining an item-retaining surface for retaining the items in the chute by supporting a lowermost item of the stack. Each pusher finger is arranged for travel through the item-discharging end for pushing all items forming part of the stack in the chute and being situated in a path of travel of the pusher finger, off the item-retaining device and for advancing the items in the conveying direction along the working flight. A height-adjusting device sets the component into different selected positions for changing a vertical distance of the item-retaining surface from the working flight to vary a number of items forming part of the stack in the chute and being situated in the path of travel of the pusher fingers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic plan view, with block diagram, of an apparatus incorporating the invention. 
     FIG. 2 is a schematic top plan view of a preferred embodiment of the invention. 
     FIG. 3 is a schematic side elevational view of the structure shown in FIG.  2 . 
     FIG. 4 is an enlarged fragmentary top plan view of the structure shown in FIG.  2 . 
     FIG. 5 is a sectional view taken along line V—V of FIG.  4 . 
     FIG. 6 is a top plan view of a detail of an another preferred embodiment. 
     FIG. 7 is a side elevational view of the structure shown in FIG.  6 . 
     FIG. 8 is a sectional front elevational view of the structure shown in FIG.  7 . 
     FIG. 9 is a fragmentary side elevational view, similar to FIG. 3, of a further preferred embodiment. 
     FIG. 9 a  is an enlarged sectional side elevational detail of FIG.  9 . 
     FIG. 10 is a sectional front elevational view of the structure shown in FIG.  9 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 schematically illustrates the control system of an apparatus according to the invention. The apparatus includes a conveyor  10  which advances, in a conveying direction A, an item group  11  under formation, composed of flat, superposed disk-like items  12 , to a packing machine  13  in which the groups are wrapped. The wrapped groups  11  are discharged onto an output conveyor  14 . The groups  11  are advanced by pusher fingers  18  mounted on the conveyor  10 . Above the conveyor  10  a plurality (for example, three, as shown in FIG. 1) curved chutes  16   a,    16   b  and  16   c  are arranged in a series as viewed in the conveying direction A. Items  12  are continuously introduced into the chutes at the top to maintain respective item stacks therein. The lower, terminal chute portion which is positioned above the conveyor  10  has a vertical orientation. The lowest item  12  in each chute  16   a,    16   b  and  16   c  is supported on an adjustable item-retaining device driven by respective motors  17   a,    17   b  and  17   c.  At least in one of the positions of the item-retaining device at least the lowermost item of the respective chute  16   a,    16   b  or  16   c  is pushed out of the chute by means of a finger  18  forming part of the conveyor  10 . The item moved out in this manner from the chute  16   a  is, by means of the respective finger  18 , pushed through underneath the lower ends of the chutes  16   b  and  16   c  and, at the same time, an item  12  is moved out of these chutes so that groups  11  of superposed items will form. The packing machine  13  has a motor  19  for forming a longitudinal seam of a wrapper folded about such group as well as a motor  20  for driving transverse sealing shoes. Further, a motor  21  is provided for driving the conveyor  10 . All the motors  17   a,    17   b,    17   c,    19 ,  20  and  21  are provided with a respective angular position sensor whose signals are applied to a common control apparatus  22  which controls the motors. Such angular position sensors are shown at  17   d,    17   e  and  17   f  for the respective motors  17   a,    17   b  and  17   c.  Additionally, signals generated by the sensors  23   a,    23   b  and  23   c  are applied to the control apparatus  22 . These sensors are situated at an upper portion of the respective chutes and their signals thus indicate the presence or absence of the top item of a stack  24  in the respective chute  16   a,    16   b  or  16   c  at the height position of the respective sensors  23   a,    23   b  and  23   c.  The sensors  23   a,    23   b  and  23   c  may be, for example, optical barriers operating on reflecting light. 
     FIGS. 2-5 illustrate a structural embodiment of the gathering and grouping apparatus according to the invention. The conveyor  10  includes an endless chain  27  circulating about sprockets  26 . The upper reach of the chain  27  constitutes the working flight  28 . The pusher fingers  18  are secured to the chain  27  and extend through a longitudinal slot  29  formed in a slide  30  serving as a gathering guide on which the groups  11  of items  12  are formed and advanced. 
     At the lower end of each chute  16   a,    16   b  and  16   c  an adjustable item-retaining device is disposed. Each item-retaining device is formed by two side-by-side arranged disks  32  rotatable about a vertical axis of a shaft  31 . The disks  32  have on their upper face at least two item-retaining surfaces  33 ,  34  a lower surface  33  and an upper surface  34  spaced at an axial distance from one another and connected to one another by helical oblique surfaces  35 . The axial distance of the surfaces  33  and  34  from each other is approximately an integer multiple of the thickness of an item  12 . One of the shafts  31  of each disk pair is driven by a respective servomotor  17   a-   17   c.  The other of the shafts  31  of the disk pair is mechanically coupled to the first-noted shaft, for example, by means of belt sprockets  36  and a toothed belt  37  or a chain to obtain a synchronous, oppositely directed rotation. At each chute  16   a,    16   b  and  16   c,  downstream of the respective disks  32  and above the generally horizontal slide  30 , two inclined slide plates  38  are arranged whose upper edge is situated slightly below the level of the lower supporting surface  33  of the disks  32 . The lower, downstream edge of the slide plates  38  is progressively at a higher level as viewed for the consecutive chutes  16   a-   16   c.  The slides  30  are bounded by lateral guides  39  for guiding the groups  11  under formation. 
     Turning to FIG. 3, the input end of the packing machine  13  is shown symbolically. Wrapping material  44  is drawn off a supply reel  43  and is folded about the item groups  11  by means of a conventional folding box, not shown. The downstream sprocket  26  for the chain  27  is situated in the region of the folding box. The longitudinal edges of the wrapper sheet are subsequently sealed and thereafter a transverse sealing is performed in a conventional manner between the wrapped groups  11 . 
     In the description which follows, the normal operation of the above-described apparatus will be set forth. 
     The two cooperating disks  32  of one of the chutes  16   a-c  are rotated (angularly positioned) in such a manner that the lowest item  12  lies on the lower supporting surface  33  and in each instance two items  12  are pushed out of the chute by the fingers  18 . The disk pairs of the other two chutes are rotated in such a manner that the lowest item  12  lies on the upper supporting surface  34  and thus only a single item  12  is moved out of the respective chute. Thus, from chute  16   a  a stack of two items moves towards the chute  16   b  where a single item is deposited on the stack which continues to the chute  16   c  where a fourth single item is placed on the three-time stack. In this manner, groups  11  of four items  12  each are formed. In the normal operation when all chutes are uniformly supplied with items, the removal of two items uniformly alternates in the three chutes  16   a-c;  in such an operation the disks  32  are periodically rotated by 90°. 
     If, however, in one of the chutes  16   a-c  the respective sensor  23   a-c  is activated and reports the absence of an item (that is, the uppermost item of the stack in that chute is situated below the sensor), then as long as the sensor continues to report such an absence, the respective disk pair is rotated automatically into such a position that the article stack will lie on the supporting surface  34  and thus continuously only a single item is pushed out from that chute by the fingers  18 . In this manner the non-uniform supply of items  12  to the chutes  16   a-c  is automatically compensated for. 
     By adjusting the height of the chutes  16   a-c  and the disks  32  the apparatus may also be driven in such a manner that selectively only one item  12  or no item is pushed out by the fingers  18  as indicated in FIG.  5 . 
     In case even larger fluctuations of the supply rate need to be compensated for or in case groups with more than four items have to be formed, the disks  32  are replaced by other disks of such a construction that the supporting surfaces  33 ,  34  have three different levels so that selectively no item or one or two items may be simultaneously removed from the respective chute. The apparatus thus has a great flexibility and may be adapted readily to changing operating conditions. The apparatus makes possible a high output while gently treating the items and also permits a selective charging rate from the various chutes. It is to be understood that more than three chutes may be provided with the associated switching means. 
     A second embodiment illustrated in FIGS. 6,  7  and  8  differs principally from that of the embodiment illustrated in FIGS. 2-5 in that the disks  32 ′ have only a single supporting surface  33  lying in one radial plane but have two diametrically opposite cutouts  47 . The thickness of the disks  32 ′ is slightly less than twice the thickness of the individual items. The two slide plates  38  include a horizontal portion  38   a  disposed directly underneath the disk  32 ′. 
     In operation the disks  32 ′ may be angularly positioned (turned) such that they assume a first mode in which one of the supporting faces  33  of each disk  32 ′ is situated underneath the chute  16   a  as shown in FIG.  8 . In such a case, the fingers  18  do not push out any item from the chute  16   a.  In another mode, one of the cutouts  47  of each disk  32 ′ is situated underneath the chute  16   a  so that the lowermost item  16  is supported on the slide plate portion  38   a  as shown in FIG.  7 . In such a case in each instance two items  12  are pushed out of the chute  16   a  by the fingers  18 . The switchover from such a mode into the first mode is performed upon passage of a finger  18  in such a manner that the supporting surfaces  33  are slid underneath the stack  24  of the items  12  in the chute  16   a  at a time when the stack  24  is still supported by the two items  12  just leaving the chute as shown in FIG.  6 . This embodiment is particularly adapted for less delicate items  12 . 
     The disk thickness may also be selected such that only a single item  12  is pushed out of the chute. The two oppositely located wings of the disks  32 ′ may be of unlike thicknesses such that one wing is approximately only as thick as an item  12 . In such a case, alternatingly zero, one or two items  12  may be moved out of the chute. Also, in the embodiment according to FIGS. 6,  7  and  8 , two or more chutes may be arranged in series along the conveyor  10 . 
     According to another embodiment of the invention, the adjustable item-retaining device at the lower end of the chutes may be constituted by vertically adjustable slide plates that may be set, corresponding to the item thickness, in two or more steps by means of pneumatic cylinders. 
     In FIGS. 9 and 10 a further embodiment is illustrated which corresponds generally to that shown in FIGS. 6,  7  and  8  and which thus has disks  32 ′ provided with recesses and horizontal slide plate portions  38   a  which extend underneath the chutes (by way of example chute  16   a  is illustrated). The diameter of the supporting surfaces  33  is, in this embodiment, less than in the embodiment according to FIGS. 6,  7  and  8  and the slide plate portions  38   a  are narrower and are arranged externally of the periphery of the supporting surfaces  33 . The slide plate portions  38   a  as well as the disks  32 ′ are height-adjustable. For this purpose, the slide plate portions  38   a  are mounted on a carrier  50  which, by means of a parallelogram linkage  51 , is mounted such that it is vertically movable on the chute  16   a.  The carrier  50  is, by means of a drive  52  (such as a pneumatic cylinder) vertically adjustable between limits set by adjustable stops  53 . The stroke between the stops  53  is set such that it equals the thickness of an item  12 . In the lower end position of the carrier  50  two items  12  are simultaneously removed, and in the upper end position one item  12  is removed if the disks  32 ′ are angularly positioned such that the apertures  47  (not visible in FIGS. 9 and 10) are situated underneath the chute  16   a.  The slide plate portions  38   a  are connected by hinges  54  with the inclined slide plates  38 . 
     The motor  17  and the two disk shafts  31  are mounted on a further carrier  56  which is movably supported in a vertical direction between two adjustable stops  58  by means of a linear guide  57 . The carrier  56  is connected with a further drive  59  (such as a pneumatic cylinder). The stops  58  are so set that the stroke of the carrier  56  is slightly greater than twice the thickness of the items  12  and further, the supporting surface  33  is, in the lower end position of the carrier  50 , slightly underneath the upper side of the slide plate portions  38   a  when the latter are in the lower position. 
     In operation, when one item  12  (in the upper end position of the carrier  50 ) is pushed out of the chute  16   a  or when two items  12  (in the lower end position of the carrier  50 ) are pushed out, the carrier  56  is always in the upper terminal position and the disks  32 ′ are, in the manner shown in FIG. 6, rotated in synchronism with the outward motion of the items  12 , so that the lowermost remaining item  12  of the stack  24  is continuously supported from below in the chute  16   a.  If the successive finger  18  is again to push out one or two items from the chute  16   a,  first the carrier  56  is lowered so that the lowermost item  12  of the stack  24  arrives over its entire length into simultaneous contact with the slide plate portions  38   a.  Thereafter, the disks  32 ′ are rotated about 90° and the carrier  56  is again raised into its upper end position. The drives  52  and  59  are also controlled by the control apparatus  22 . 
     In the embodiment shown in FIGS. 9 and 10 an only one-sided support of the lowermost item  12  remaining in the chute  16   a  is avoided during the removal of items  12  and therefore such lowermost item does not drop onto the slide plate portions  38   a  but is deposited gently thereon. This embodiment therefore is adapted particularly for delicate items such as rectangular confectionary products which have a break line across their longitudinal middle to facilitate breakage into two halves. Selectively, no items or one or two items  12  may be pushed out of the chutes. 
     As a variant of the embodiment of FIGS. 9 and 10, the carrier  50  may be adjustable in two steps corresponding to the thickness of the items  12 . In such an arrangement, the drives  52  and  59  may be, for example, servomotors which include angular position sensors and rotate threaded spindles carrying traveling nuts affixed to the carriers  50 ,  56 . The stroke of the carrier  56  is set to slightly more than three times the item thickness. In this embodiment, selectively no item or one, two or three items  12  may be pushed out of the chute  16   a.  The stroke velocities of the carriers  50 ,  56  is varied from zero to a maximum and then to zero by conventional electrical or mechanical means. 
     In FIG. 9, yet another alternative for the height adjustment of the disks  32 ′ is shown in broken lines. The carrier  56  is connected rigidly with the chute  16   a;  the drive  59  as well as the stops  58  and the guide  57  are dispensed with. The lower portion  31   a  of the shafts  31  is connected torque-transmittingly, but shiftable axially with the upper shaft part by means of a coupling  62 . Also referring to FIG. 9 a,  as cam  63 , rigidly connected with the shaft part  31   a,  runs in a stationary guide track (cam track)  64 . The stroke of the disks  32 ′ is thus coupled with the rotary motions thereof. The cam track  64  is designed such that immediately prior to reaching the position in which the rear edge of the supporting surface  33  (as viewed in the direction of rotation) arrives underneath the upstream edge of the chute  16   a , the disks  32 ′ are lowered and thus the lowermost item  12  is deposited on the slide plate portions  38   a.  Thereafter the disks  32 ′ are rotated into the position where the aperture  47  lies underneath the chute  16   a . Upon passage of the successive finger  18  the disks  32 ′ are again rotated by 180° and are first lifted by the cam track  64  so that the disks  32 ′ are in the upper position when the forward edge of the respective supporting surface  33  arrives underneath the rearward chute edge. In this variant the number of the items  12  that are pushed out of the chute  16   a  can be selected only according to the number of stages between which the carrier  50  may be height-adjusted. This variant has the advantage that it is simpler and more economical. 
     While the structures described in connection with FIGS. 5 to  10  were related to the first chute  16   a , it is to be understood that any or all chutes may be provided with such constructions. 
     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.