Patent Publication Number: US-6668523-B2

Title: Process for the final folding and subsequent storage of a piece of linen

Description:
This is a continuation of application Serial No. 09/264,859, filed Mar. 9, 1999 now U.S. Pat. No. 6,305,146 which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     A. Field of the Invention 
     The invention relates to a process for the automatic final folding and subsequent storage of a piece of linen and a final folding apparatus for folding a piece of material, such as a linen, and transferring it for subsequent storage. A known process of this general type and such a final folding apparatus are described, for example, in the brochure JENSEN TEXTILE JENTEX from AKAB of Sweden AB, Bussgatan 4, SE-504 94 and from Jensen AG Burgdorf, CH-3400 Burgdorf. 
     B. Description of the Related Art 
     The known process of the general type is suitable for folding a piece of linen to a specific final dimension where the weight of the parts themselves is sufficient to hold the piece of linen in the final configuration achieved. Recently, however, especially with regard to the desire for the folded pieces of linen to occupy a small area in deliveries and the like, requirements are set with respect to the final dimension which can no longer be met by automatic folding in a conventional manner since the pieces of linen folded very small immediately open again, completely or partly eliminating the final folding. 
     Folds to such final dimensions have therefore been carried out manually to date, which however requires considerable effort owing to the high folding pressure to be applied and the required control over the piece of linen until storage or intermediate storage. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to develop the known process of the generic type so that it permits automatic final folding of a piece of linen to a small final dimension. This object is achieved by an apparatus for folding material having a draw-in surface defining a gap, a folding member configured to be advanced and retracted through the gap, and a transfer mechanism. The transfer mechanism is aligned with the gap an disposed on a side of the draw-in surface opposite to the folding member in retracted position. The transfer mechanism comprises a receptacle including parallel first and second surfaces configured to engage respective outer surfaces of the folded material prior to transfer. The second surface is movable relative to the first surface between and engaged position engaging the outer surface of the folded material and a disengaged position allowing the folded material to be transferred from the receptacle. The apparatus according to the present invention is suitable for carrying out final folding to small final dimensions. 
     Another aspect of the invention includes a process for the automatic final folding of material including a final folding leading to a configuration having a first outer surface and a second outer surface parallel to the first outer surface. The process includes directing forces on the outer surfaces toward each other after the folding step. The forces are continued during transfer of the folded material from a folding section to subsequent storage, wherein the forces result from stops acting against the outer surfaces of the folded material. 
     The advantages achieved by the invention are that pieces of linen can be automatically folded to very small final dimensions and can be brought to a stable storage position. In particular, for example, bed sheets can be folded to 9″×6″ so that they require a very small area. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The invention is illustrated in more detail below with reference to Figures which merely represent embodiments. In the drawings, 
     FIG. 1 a  shows a side view of a novel final folding means, according to a first embodiment of the invention, in a first phase of final folding with subsequent stacking, 
     FIG. 1 b  shows a side view corresponding to FIG. 1 a , with the final folding means in a second phase of final folding with subsequent stacking, 
     FIG. 1 c  shows a side view corresponding to FIG. 1 a , with the final folding means in a third phase of final folding with subsequent stacking, 
     FIG. 2 a  shows a plan view of the final folding means of FIG. 1 c , 
     FIG. 2 b  shows a plan view corresponding to FIG. 2 a , with the final folding means in a fourth phase of final folding with subsequent stacking, 
     FIG. 2 c  shows a plan view corresponding to FIG. 2 a , with the final folding means in a fifth phase of final folding with subsequent stacking, 
     FIG. 3 a  shows a side view of a novel final folding means according to a second embodiment of the invention, in a first state, and 
     FIG. 3 b  shows a side view corresponding to FIG. 3 a , with the final folding station in a second state. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present preferred embodiments of the invention illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. 
     According to a first embodiment, the final folding station according to the invention comprises a folding apparatus  1  having a first draw-in belt  2  and a second draw-in belt  3  whose upper belt sides form an upward-facing draw-in surface  4  for receiving a piece of linen  5 , which draw-in surface is interrupted by a gap  6 . Arranged above the conveying surface  4  are two guide belts  7 ,  8  whose lower belt sides form a guide surface  9  which is parallel to the draw-in surface  4  and is likewise interrupted above the gap  6 . The draw-in surface  4  and the guide surface  9  between them form a draw-in channel  10 . 
     Rollers  11 ,  12 , over which the draw-in belts  2 ,  3  are guided at the gap  6 , can be pulled back from a starting position of the final folding means (FIG. 1 a ) by pneumatic cylinders  13 ,  14  for widening the gap  6 . A folding sword  15 , likewise in the starting position, is arranged above the guide belts  7 ,  8 . It can be lowered through the gap in the guide surface  9  and the gap  6  underneath in the draw-in surface  4 , by an actuating device which is not shown. 
     A transfer device  16  is arranged below the folding apparatus  1 . Said transfer device comprises a frame  19  which can be rotated about a perpendicular axis  17  by means of a pneumatic cylinder  18  and which carries a receptacle  20  which is a distance away from the axis  17  and, in the starting position, is arranged directly below the gap  6  and is parallel to it. It is bounded by a back panel  21  and two wings  22   a, b  which are arranged a distance away from said back panel, can be folded away outwards about perpendicular axes against elastic forces and form approximately parallel stop surfaces  23  and  24 , respectively, which face one another and may diverge slightly from one another at the upper edges. Behind the back panel  21  and fastened to the frame  19  is a further pneumatic cylinder  25  whose piston carries a [disc-shaped ram  26  which,] disc-shaped ram, alternatively referred to as a “first stacking member,” which when in the starting position, is present behind the back panel  21  and can be moved forward through a round opening in said back panel and between the wings  22   a ,  22   b.    
     The frame  19  can be swivelled from the starting position about the axis  17  into a transfer position (FIGS. 1 c ,  2   a ), in which a stacking line  27  (FIGS. 2 a-c , omitted in FIGS. 1 a-c ) directly adjoins the receptacle  20 . Said stacking line has a sliding plate  28 , alternatively referred to as a “second stacking member,” and lateral guide plates  29   a, b  which together bound a stacking channel  30  which declines slightly towards the receptacle  20 . The stacking channel  30  is closed off from the receptacle  20  in a starting position (FIG. 2 a ) by two slides  31   a, b  which are provided in the middle with semicircular recesses and can be laterally retracted by means of two pneumatic cylinders  32   a, b . On the opposite side, it is bounded by a pressure plate  33  which can be moved with application of a certain pressure towards that end of the stacking line  27  which is opposite the receptacle  20 . The transfer device  16  may also be formed in such a way that it can assume a plurality of transfer positions characterized by various angles of rotation of the frame  19  relative to the axis of rotation  17  and from which positions the stacking lines, which may be formed identically to the stacking line described, radiate outwards in a star-like manner. 
     The final folding means shown in FIGS. 1 a-c ,  2   a-c  may be formed as an independent module which connects with a folding station of a known type. The piece of linen  5  arriving from the folding station, for example a bed sheet which was brought to a size of 9″×12″ by being folded several times, is drawn into the draw-in channel  10  at the left end of the final folding means by corresponding movement of the first draw-in belt  2  and of the first guide belt  7  and, finally also by means of the second draw-in belt  3  and of the second guide belt  8 , is moved to the right until its middle is located exactly above the gap  6  and below the folding sword  15  (FIG.1 a ). 
     Final folding is then formed by widening the gap  6  by slightly pulling apart the rollers  11 ,  12  and lowering the folding member, such as, for example, sword  15  through said gap and thus pressing the piece of linen  5  so that the middle of its lower side moves downwards into the receptacle  20 , while at the same time its laterally connecting parts are folded back by contact, or engagement, with the stop surfaces  23 ,  24  so that they form parallel outer surfaces of the finally folded piece of linen  5 , which now has final dimensions of 9″×6″. Opening of the piece of linen  5  is prevented by the further action of the stop surfaces  23 ,  24 , which exert forces of reaction which are directed at the outer surfaces towards the middle of the receptacle  20 . The piece of linen  5  is therefore held by said forces in the final configuration achieved, against its tendency to unfold again (FIG. 1 b ). 
     The frame  19  is then rotated by means of the pneumatic cylinder  18  through 90° to a transfer position so that the receptacle  20  is now directly opposite one end of the stacking line  27  (FIGS. 1 c ,  2   a ). After retraction of the slides  31   a,b , the piece of linen  5  can then be pushed into the stacking channel  30  by advancing the ram  26  while the wings  22   a,b  swivel away laterally (FIG. 2 b ) to disengage from the outer surface of the linen, after which the slides  31   a,b  travel back to the starting position (FIG. 2 c ). The ram  26  can then be withdrawn through the circular opening formed by the recesses in the slides  31   a,b  and further between the wings  22   a,b  and through the opening in the back panel  21 . 
     The finally folded piece of linen  5  is now in a storage position in which it rests with one of its outer surfaces against a corresponding outer surface of a previously finally folded piece of linen  5 ′, and with its opposite outer surface, parallel to the first-mentioned outer surface, against the slides  31   a,b . It is obvious that the two outer surfaces of a piece of linen each rest against an outer surface of an adjacent piece of linen or against another stop surface formed by the slides  31   a,b  or the pressure plate  33 . Consequently, each piece of linen is fixed in its final configuration in this storage position and opening of the final fold cannot occur. When stacking line  27  is full, or even earlier, the stack as a whole can be removed and, for example, packed. If a plurality of stacking lines and corresponding transfer positions are present, the latter can be approached, for example, alternately so that the stacking lines are filled uniformly. 
     According to a second embodiment, the final folding means according to the invention once again comprises a folding apparatus  1  which, with draw-in belts  2 ,  3  and guide belts  7 ,  8 , whose upper and lower belt sides form a draw-in surface  4 , interrupted by a gap  6 , and a corresponding guide surface  9 , which enclose a draw-in channel  10 , and, with a folding sword  15 , essentially corresponds to the folding apparatus of the final folding means according to the first embodiment. However, the draw-in channel  10  slopes upwards and the folding sword  15  is inclined in the draw-in direction of the piece of linen  5 . In addition, only the roller  11 , over which the first draw-in belt  2  runs, is displaceable for changing the width of the gap  6 , but not the opposite roller  12 . A horizontal feed belt  34  is arranged upstream of the first draw-in belt  2 . 
     Present directly below the gap  6  is a folding belt  35  which slopes slightly downwards and whose upper belt side forms, with that belt side of the second draw-in belt  3  which runs above said folding belt, a folding channel  36  which extends to the end of the folding apparatus  1 . The folding apparatus  1 , as well as a subsequent packing apparatus  37 , is in the form of an independent transportable station. 
     The packing station  37  has, at the entrance, an approximately horizontal first transfer belt  38  whose upper belt side, together with that lower belt side of an upper transfer belt  39  which runs parallel above said upper belt side, bounds a transfer channel  40  which is directly adjacent to the folding channel  36  and leads to a packing channel  41  which is likewise virtually directly adjacent and is present between an upper belt side of a first packing belt  42  and that belt side of a second packing belt  43  which runs parallel above said first packing belt. The widths of the transfer channel  40  and of the packing channel  41  correspond approximately to the width of the folding channel  36 . 
     Arranged below the first packing belt  42  and above the second packing belt  43  are storage rollers  44  and  45 , respectively, which each carry a web  46  and  47 , respectively, of a strip-like weldable packaging material, for example a plastics film, which is guided over a guide roller  48  or  49 , respectively, arranged upstream of the first packing belt  42  and of the second packing belt  43 , respectively, into the packing channel  41 , where it is present between the first packing belt  42  or the second packing belt  43  and any piece of linen  5 . Arranged directly behind the end of the packing channel  41  is a connecting device having two heatable welding stamps  50 ,  51  which can be advanced towards one another perpendicularly to the middle of the packing channel  41  and which is followed by a delivery belt  52  at the height of the first packing belt  42 . 
     A piece of linen  5  placed on the feed belt  34  or arriving from an upstream folding apparatus is drawn into the draw-in channel  10  at the left end of the final folding means by corresponding movement of the first draw-in belt  2  and of the first guide belt  7  and, finally also by means of the second draw-in belt  3  and of the second guide belt  8 , is moved to the right until its middle is present above the gap  6  and inclined below the folding sword  15  (FIG. 3 a ). 
     The final fold is then performed by widening the gap  6  by slightly drawing back the roller  11  and by moving the folding sword  15  through said gap obliquely downwards and thus pushing the piece of linen  5 , with the middle of its lower side facing forwards, into the folding channel  36 . The second draw-in belt  3  and the folding belt  35  are moved in such a way that they accompany and support the movement of the piece of linen  5  (FIG. 3 b ). This movement of said belts is maintained until the piece of linen  5  leaves the folding apparatus  1  at the end of the folding channel  36 , while the folding sword  15  is withdrawn (FIG. 3 a ). 
     The piece of linen  5  now enters the transfer channel  40  of the packing apparatus  37 , where it is transported onwards by corresponding movement of the first transfer belt  38  and of the second transfer belt  39  and is finally pushed into the packing channel  41  between the webs  46 ,  47  of packaging material (FIG. 3 b ). Once it has reached the end of the packing channel  41 , the contact with the first transfer belt  38  and with the second transfer belt  39  ceases and the piece of linen abuts a weld seam which is made by means of the welding stamps  50 ,  51  and joins the webs  47 ,  48 . After withdrawal of the welding stamps  50 ,  51 , the packing belts  42 ,  43  are set in motion so that, with simultaneous withdrawal of packaging material from the storage rollers  44 ,  45 , the piece of linen  5  is transported out of the packaging channel  41  and reaches the delivery belt  52 . In this position, the welding stamps  50 ,  51  are advanced and the webs  47 ,  48 —now behind the piece of linen  5 —are welded again (FIG. 3 b ). 
     The piece of linen  5  has now been brought to a storage position in which it is surrounded by a closed strip  53  of packaging material which consists of two part-strips which are formed from sections of the webs  46 ,  47  and are connected by two weld seams. The part-strips now exert forces of reaction on the parallel outer surfaces of the piece of linen  5 , which forces are directed towards one another and once again prevent opening of the final fold and fix the piece of linen  5  in its final configuration. It is possible to provide further welding stamps, by means of which lateral weld seams joining the part-strips are additionally made, so that said weld seams result in completely closed packaging of the piece of linen. In this case, the webs of packaging material must of course be correspondingly broader than the piece of linen, whereas, in the case described above, they preferably have about the same width but may also be narrower. After further transport on the delivery belt  52 , the packed pieces of linen are ejected, whereupon they are separated at the weld seams. 
     What is decisive for carrying out the process successfully, if it is to be effective on the final folding means according to the first or that according to the second embodiment, is that, after the final folding, pressure is maintained constantly on the parallel outer surfaces of each piece of linen until the latter has been fixed in its final configuration by stacking or packing or in another manner, in a storage position. In the first case, this is effected essentially by the stop surfaces of the receptacle, and in the second case essentially by the transfer belts. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only. Thus, it should be understood that the invention is not limited to the illustrative examples in this specification. Rather, the invention is intended to cover all modifications and variations that come within the scope of the following claims and their equivalents.