Abstract:
A bead roller sheet metal working machine having a first drive shaft and a second drive shaft arranged in a plane common to both drive shafts, wherein both drive shafts at their respective inner ends are driven by means of a drive unit which by a first transmission drives the drive shafts to rotate in opposite rotational directions, and where the drive shafts at their respective outer ends are equipped with dies by way of which the sheet can be provided with beads when the sheet is forwarded between the dies along a plane substantially tangential and common to both dies, and where a greater part of mutually facing surfaces of two arms carrying the drive shafts are located at a greater distance from one another than a distance between the outermost ends of the drive shafts to allow a curved work piece access to the machine while working.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims foreign priority from Swedish Application No. SE1100430-6 filed on Jun. 1, 2011, and incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a bead roller for use in connection with sheet metal working, where a thin sheet can be shaped and provided with beads by feeding the sheet between dies of the machine. 
     BACKGROUND OF THE INVENTION 
     Bead rollers are used in techniques for sheet metal shaping to achieve stiffening of sheets, to model a sheet metal to a desired structure or to design a sheet as desired. The stiffening or the design is accomplished by providing the sheet with profiles, such as beads in the form of notches, steps or ridges, which may be linear or curved as desired, along the sheet. 
     In the automotive industry there are a lot of sheet details which may have to be shaped into different designs. With regard to types of vehicles manufactured in series it is obvious to use pressing tools which model sheet details for a specific type of vehicle in a press, where sheets aimed for a specific location in the vehicle are stamped in a desired amount having identical designs or patterns. On the other hand, if vehicles like cars or motor bikes are manufactured in solitary numbers, it would be too costly to utilize a number of different presses to model different sheet details, for example details of the coach of a car, fenders of a motor bike, etc. In cases like that, where solitary details are to be shaped of sheets to constitute, for example, fenders, sides of doors, bonnets, lids or other details of a vehicle, a bead roller can be used to model the sheet to the stiffness, structure and design desired. 
     Bead rollers are known since long. Examples of such machines are disclosed in Published European Patent Application EP1518616 A2 and U.S. Pat. No. 6,591,651, both of which are incorporated herein by reference. The function of a known bead roller, exemplified by said documents is described in the following with reference to  FIGS. 1 ,  2   a  and  2   b.    
       FIG. 1  depicts a conventional Prior Art bead roller. Machine  101  is, in this case a model mounted to the floor by means of a floor stand  102 . Further, machine  101  comprises two drive shafts  103  and  104  ( FIGS. 2   a ,  2   b ) mounted in parallel. The ends of shafts  103  and  104  are adapted to receive different types of dies  105   a ,  105   b  (shown in  FIGS. 2   a ,  2   b ) depending on the type of bead desired, on a sheet being fed between dies  105   a ,  105   b . Drive shafts  103 ,  104  are journaled in bearings in respective arms  106 ,  107  and have their inner ends connected to respective gear wheels and transmission to a motor  108  for driving shafts  103  and  104 . Arms  106 ,  107  are fixed to floor stand  102 , usually in such a way that drive shafts  103  and  104  are parallel to the ground on which floor stand  102  is mounted. The drive of the shafts  103  and  104  is arranged so that the dies counter rotate and thereby feed a sheet plate contacting dies  105   a ,  105   b  from the upper and lower side, respectively, in a forward direction (normally away from an operator). On the upper arm  106 , in this example, a screw  109  is mounted. By means of this screw  109 , a desired pressure between dies  105   a ,  105   b  can be set. 
     Operation of the prior art bead roller is illustrated in  FIGS. 2   a  and  2   b . In these Figures, being principal outlines, drive shafts  103  and  104  and their mountings in bearings in the arms  106 ,  107  are shown more in detail. A sheet  110  and an ongoing shaping of sheet  110  are also visible.  FIGS. 2   a  and  2   b  depict how a bead, in this case being a ridge along the sheet, is accomplished. For this purpose a first die  105   a  and a second die  105   b  are mounted on the outer end of the respective drive shafts  103 ,  104 . The first die  105   a  is furnished with a circumferentially running sunk recess  111   a , while the second die  105   b  is furnished with a circumferentially running ridge  111   b  corresponding to and matching the curvature of said recess  111   a . As dies  105   a ,  105   b  are counter rotating with respect to each other when driven by shafts  103 ,  104 , sheet  110  will be fed forward between dies  105   a ,  105   b  with a pressure is set as desired, whereby a bead will be shaped, in this case as a bead designed as a ridge extending a desired length across the sheet  110 . By manually steering the sheet in different directions during the operation in a plane substantially tangentially with the two dies  105   a ,  105   b , a desired curvature of the bead can be accomplished. The cross sectional profile of the bead is determined by the choice of the two matching dies  105   a ,  105   b.    
     With reference to  FIG. 3 , it is illustrated how difficulties can occur during the described sheet working according to Prior Art. A simple embodiment of a bead roller according to conventional technology is depicted schematically, simplified and stereotyped in  FIG. 3 . According to  FIG. 3 , a bead, in this case a ridge elevated from the sheet surface along a curve in the middle of the exterior surface of a fender  110  of a motorbike is under preparation. As clearly disclosed by the figure it will be impracticable to achieve the desired bead in this case, as the restricted space between the two drive shafts  103 ,  104  prevents the introduction of one of the lengthwise edges  113  of the fender between the drive shafts  103 ,  104  of the machine due to the heavy bend in the fender cross section.  FIG. 3  illustrates how the edges of the fender intersect deeply into the area  113 , which needs to be freely available to carry out the described operation. In the case exemplified, drive shaft  104 , and of course also a housing, for example the housing of an arm  106 , surrounding drive shaft  104 , block the desired actions on the maneuvering of the fender. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a bead roller for sheet metal shaping. 
     One object of the invention is to arrive at an increased maneuverability and to obtain more working space when working with a sheet in the bead roller. This is achieved by making the area between the drive shafts larger than what has been prevailing with Prior Art machines of this kind. The increased area between the drive shafts is made possible by means of restructured the drive and a division of one or both of the drive shafts of the machine. The area between the drive shafts, in a plane common to both shafts, is limited by the edges constituted by the drive shafts and distances drawn between corresponding mountings at the ends of the drive shafts. 
     A substantial advantage of the present invention in relation to corresponding Prior Art machines is the increased maneuverability for work pieces when profile on a sheet plate work piece is to be carried out. 
     By the arrangement of a substantially greater maneuvering space between the drive shafts of the dies as described below, according to the present invention, possibilities to perform the sheet working on sheet work pieces having strong curvatures in a plane common to the plane through both drive shafts can be achieved. By this is meant that a drive shaft, as in a conventional arrangement, will not be a hindrance for the forwarding of said sheet work piece between the dies. Where profiles on sheets are to be effected, the inventive machine allows a substantially increased number of operations to be accomplished compared to what has been possible by use of current and conventional bead rollers. 
     The inventive bead roller is characterized by that the major part of the surfaces of the two arms facing each other and enclosing the drive shafts driving the dies are located at a greater distance from each other than the distance between the outermost ends of the drive shafts. It should be noted here that the term: “the outermost ends of the drive shafts” refers to the ends on which dies are mounted. Further, by said distance is meant the shortest distance between the surfaces of the drive shafts at said outermost ends. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a Prior Art bead roller being of a floor-mounted version with two arms for drive shafts. 
         FIG. 2   a  is a first perspective view of the Prior Art bead roller according to  FIG. 1 , illustrating the drive shafts and their bearing in the arms of the machine. 
         FIG. 2   b  is a second perspective view of the Prior Art bead roller according to  FIG. 1 , illustrating the drive shafts and their bearing in the arms of the machine. 
         FIG. 3  is a perspective view of a Prior Art bead roller, illustrating by means of an outline view, the impossibility to handle certain types of work pieces during sheet shaping work in the Prior Art bead roller. 
         FIG. 4  is a perspective view of a floor model of the bead roller according to the invention. 
         FIG. 5   a  is a perspective view of one embodiment of the present invention opened to show the rear wall of a housing around the respective drive shaft and which illustrates the drive shafts and a gear drive according to one embodiments of the present invention. 
         FIG. 5   b  is a perspective view of one embodiment of the present invention opened to show the rear wall of a housing around the respective drive shaft and which illustrates the drive shafts and a chain drive according to one embodiment of the present invention. 
         FIG. 5   c  is a perspective view of one embodiment of the present invention opened to show the rear wall of a housing around the respective drive shaft and which illustrates the drive shafts and a belt drive according to one embodiments of the present invention. 
         FIG. 6  schematically shows a bead roller according to the invention being used in sheet working exemplified by means of shaping a work piece having great bends. 
         FIG. 7  is a perspective view of the same type as in  FIG. 6 , illustrating a variant of the bead roller according to the present invention, where both drive shafts are divided to arrive at a larger working space between the drive shafts. 
         FIG. 8  is a perspective view of the same type as in  FIG. 7 , illustrating a variant of the bead roller of the present invention by implementing a division of at least one drive shaft of the bead roller according to the invention, where the division of a drive shaft is performed by means of universal joints between the parts of the drive shafts. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Below, a number of variants of embodiments of the invention are described and supported by the accompanying Figures. 
       FIG. 4  is a perspective view of a floor model of a bead roller  1  according to a first embodiment of the present invention. It should here, furthermore, be mentioned that details having correspondence to details of prior art designs of bead rollers, as described above, are referred to by use of the same final Figures, but details for the Prior Art machines being numbered starting from reference number  101  to avoid confusion. From the Figure it is evident that a floor stand is denoted by  2 . Upper and lower arms are denoted by  6  and  7 , respectively. Drive shafts  3 ,  4  are supported by, usually enclosed by and carried in bearings by the arms  6 ,  7 , where said drive shafts  3 ,  4  are located in a plane common to both drive shafts in a manner as described below. A drive unit  8 , here represented by an electric motor, is utilized to run the drive shafts. Instead of the use of an electric motor, other types of drive units  8  may be utilized. Simpler machines may, for example, use a crank for manual drive. A feature, outstanding for bead roller  1  according to the invention, is constituted by the increased working area between the drive shafts, i.e., the area where sheet working takes place, as represented in  FIG. 4  by the area overrun by arrow a when arrow a is moved along and between arms  6  and  7 . The increased working area is related to and compared to the corresponding working area at conventional bead rollers, so far as it is already from the example depicted in  FIG. 4  evident that one of the drive shafts  3 ,  4  is divided to render the increased area possible. The term: “area” is directed to the available free area between the two arms  6 ,  7  denoted by arrow a. 
     The arms  6  and  7  are made up of housings surrounding the drive shafts  3 ,  4  and at the same time serving as shields around these drive shafts. According to the inventive example of a bead roller having said arms  6 ,  7  enclosing drive shafts  3 ,  4  for dies  5   a ,  5   b , as depicted in  FIG. 4 , a major part of the surfaces  6   a  and  7   a  of the two arms  6 ,  7  facing each other are located at a greater distance a from each other than the distance b between the outermost ends of the drive shafts  3 ,  4 . By the outermost ends means the ends which can be provided with dies  5   a ,  5   b.    
     Arrangements to accomplish the stated structure are illustrated in  FIGS. 5   a - c , where a number of variants for drive shaft configurations are described and illustrated. If a machine according to the invention were manufactured without a protecting housing, the surfaces facing each other of the parts of the drive shafts  3 ,  4  moved apart (moved apart—as compared to conventional bead rollers) shall themselves be regarded as and be equalized to the surfaces  6   a ,  7   a  of a machine provided with a housing. In such a case, the distance a shall be looked upon as the mean distance between the major parts of the drive shafts  3 ,  4 , which at its ends can be provided with dies. 
       FIGS. 5   a  to  5   c  illustrate various embodiments where one of the drive shafts is divided.  FIGS. 5   a - 5   c  illustrate that, in these cases, the upper drive shaft  3  may be retained as an undivided drive shaft, while on the other hand the lower drive shaft  4  may be divided into one longer part  4   a  and one shorter part  4   b . Only the variant with the lower drive shaft being parted is shown, but nothing prevents that the embodiment be made inverted, i.e. that the upper drive shaft  3  is the divided drive shaft, while the lower drive shaft  4  is preserved as undivided. When use of such alternative embodiments, which are not described here, but easily perceived, such an inverted embodiment entails that the reference  FIG. 4  is amended to  3  and vice versa in all descriptions of embodiments according to  FIGS. 5   a - 5   c . Embodiments with a divided drive shaft  4   a ,  4   b  entail, according to the invention, that the shorter part  4   b  is mounted in bearings in the outer part of the lower arm  7 .  FIGS. 5   a - c  and the following Figures are perspective drawings with the outer cover removed for clarity, and thus only illustrate the rear part of a wall which constitutes a part of the arm encapsulating and supporting drive shafts  3  and  4  or the corresponding divided parts  3   a ,  3   b  and  4   a ,  4   b  of drive shafts  3 ,  4 . 
     The bead roller embodiment according to  FIG. 5   a  illustrates a variant where the parted drive shaft  4   a ,  4   b  is run by means of a drive unit  8  which by way of a first transmission  13  transfers rotational motion to both drive shafts  3 ,  4 . The first transmission  13  has to be arranged so that both drive shafts  3 ,  4  are rotated in opposite rotational directions to force a forward longitudinal movement of a sheet introduced between the dies  5   a ,  5   b  mounted on the outermost ends of the drive shafts. In the Figures depicting the invention, a screw, by means of which the bearing pressure between upper  3  and lower  4  drive shafts can be regulated as denoted by reference numeral  9 . Screw  9  extends through a thread in a dog  9   a , which is fixed in upper arm  6 , whereby a pressure against the lower drive shaft  4  with respect to arm  6  may be regulated. In  FIGS. 5   a  and the following Figures, a working plane  12  is shown between the upper die  5   a  and the lower die  5   b . Said working plane extends tangentially to both the upper  5   a  and the lower  5   b  die and will thus be substantially perpendicularly oriented to a plane through and common to both drive shafts  3 ,  4 . The sheet which is to be treated will also, at least in the area between the dies, coincide with the herein referred to as the working plan  12  during the sheet working. 
       FIG. 5   a  illustrates the division of one shaft, in this case the lower shaft  4 , achieved through an extension of the first transmission in height and being realized by means of a number of gear wheels  14  arranged in a row and further in such a way that the two drive shafts  3 ,  4  are rotated in opposite rotational directions. The longer part  4   a  of the lower drive shaft  4  is run directly by drive unit  8  and the drive of the upper drive shaft  3  is achieved by means of a desired number of gear wheels  14 , which brings about the drive of the lower shaft  4  to the upper shaft  3 . Through this measure the longer part  4   a  of the lower shaft  4  may be moved in a parallel displacement away from the working plane  12  common to the dies. The outer end of the longer part  4   a  of the lower shaft  4  is mounted in bearings of a gear box  15 , as illustrated in  FIGS. 4 and 6 . The shorter part  4   b  of the lower drive shaft  3  is mounted in bearings in the upper end of the gear box  15 . Said shorter part  4   b  is further, within the gear box  15  provided with gear wheels  16 , which serve as a second transmission  17  transferring power from the longer part  4   a  to the shorter part  4   b  of the lower drive shaft  4 . 
       FIG. 5   b  depicts an alternative embodiment of a bead roller  1 , where the configuration of the machine in principle is the same as the one described in connection with  FIG. 5   a , but here a variant of the first  13  and second transmission  17  is shown. In this embodiment, instead of using a gear wheel, a chain drive  18  is utilized at the second transmission  17  for the power transfer from the longer part  4   a  of the lower drive shaft  4  to the shorter part  4   b  of the lower drive shaft  4 . A corresponding chain drive  19  at the first transmission  13  transfers rotational motion to a second gear wheel  20  arranged to establish the counter rotational motion of the upper drive shaft  3 . 
       FIG. 5   c  illustrates a further embodiment of a bead roller, whereby also in this case the configuration of the machine in principle is the same as in  FIGS. 5   a  and  5   b . As an alternative, a variant of the first  13  and second  17  transmissions is shown. Instead of using gear wheels, a drive belt  21  is used in this case at the second transmission  17  for the transfer of power from the longer part  4   a  of the lower drive shaft  4  to the shorter part  4   b  of the lower drive shaft  4 , whereby the drive belt  13  brings about rotational motion from the longer to the shorter part of drive shaft  4 . A corresponding drive belt  22  at the first transmission  13  transfers rotational motion to a second gear wheel  20  arranged to establish the counter rotational movement of the upper drive shaft  3 . 
     There is, of course, nothing that prevents the use of a mix of transfers of power from the first  13  to the second  17  transmission, which means that a drive by means of teeth, chain or drive belt may be selected for the respective transmission  13  and  17 . As a further alternative a V-belt could be used instead of a drive belt. As a drive shaft easily could slip at heavy load on the drive shaft the solutions listed are preferred. 
     One advantage with the present invention in relation to prior art is illustrated and easily understood according to  FIG. 6 .  FIG. 6  illustrates how a bead in the shape of a ridge is prepared through a sheet shaping on a motorcycle fender  25 . Here, it is obvious that the heavy bend of the fender in the plane of the drive shafts  3 ,  4  does not give rise to any problems during the work with the sheet. This has been accomplished as the distance between the two arms  6 ,  7  behind the gear box  15  has been arranged to be so great that bent sheets can easily be handled and worked with. It is further obvious from  FIG. 6  that it is advantageous to make the gear box  15  as thin as possible in the axial direction. By designing the gear box  15  to be thin, i.e. the closer its inner wall is arranged to the dies  5   a ,  5   b , the bigger the radii of curvature of the sheet being prepared may be allowed. The choice of drive according to  FIGS. 5   a  to  5   c  has impact on the width of the gear box  15  in the axial direction. 
     As shown in  FIG. 7  both shafts  3  and  4  of the bead roller  1  may be divided and displaced in parallel away from each other and thus give a possibility to an even larger open area between the arms  6 ,  7  housing the drive shafts  3  and  4 . By this, sheets which have bends both upwards and downwards in its cross section can be handled in the machine according to the invention. The drive of both the divided shafts is hereby accomplished according to any one of the alternatives disclosed and illustrated in  FIGS. 5   a  to  5   c . The second transmission  17  may then be provided in duplicate at the outer ends of the shafts and bring about rotational motion from the longer part  3   a  to the shorter part  3   b  of the upper drive shaft  3 . The first transmission  13  may simply be made extended and, as previously discussed, takes care of the transfer of rotational motion from drive unit  8  to both drive shafts  3 ,  4 . 
     Still an alternative of an embodiment of the bead roller  1  according to the invention is illustrated in  FIG. 8 . Here, the lower drive shaft  4   a  has been divided in three parts, a longest part  4   a , a shorter part  4   b  to which one a die can be attached and a third part  4   c  being connected to the first transmission  13 . The different parts are coupled to each other by means of universal joints  26   a ,  26   b . The drive from a drive unit  8  is effected by way of the first transmission  13  to the third part  4   c  of drive shaft  4  being connected to the first transmission. The drive is further transferred by means of the first universal joint  26   a  to the longest part  4   a  of drive shaft  4 , still further through the second universal joint  26   b  to the part  4   b  of the lower drive shaft  4  carrying the die. In this case the part  4   b  carrying the die will be mounted in bearing in parallel with and close to the upper drive shaft  3  in a bearing in gear box  15  as previously disclosed. As a result, the longest part  4   a  of the drive shaft may be inclined away from the tangential plane  12  common to both dies  5   a ,  5   b . In this way the space between the drive shafts for maneuvering a sheet during work in said space may be increased deeper into the machine, compared to what is possible by use of prior art machines. The first transmission  13  may transfer rotational motion from the drive unit  8  to both drive shafts  3 ,  4  by means of gear wheels  27 , whereby the third part  4   c  of drive shaft  4  connected to the first transmission  13  is coupled to one of said gear wheels  27  of first transmission  13 . 
     In a way corresponding to the division of the lower drive shaft  4 , alternatives may be implemented, whereas the upper drive shaft  3 , or both lower  4  and upper  3  drive shaft may be divided and be driven by use of universal joints  26   a ,  26   b  as just described above with respect to one drive shaft. The division of the upper drive shaft  3  and the universal joint drive of this shaft correspond to the just described universal joint drive of the lower drive shaft  4 . If both drive shafts are provided with universal joint drive in the way as described more than two gear wheels  27  may be needed in the first transmission  13 . 
     The bearing for the shorter part  4   b  in the gear box  15 , as well as the bearing for the part  3   b  of upper shaft  3  provided with a die in arm  7 , are arranged at a distance from each other so that the dies  5   a ,  5   b  designed to be attached on the outermost ends of drive shafts  3 ,  4  will abut each other. 
     An alternative to the embodiments as disclosed above is to use an inclined drive shaft having, in principle, the same inclination as the longest part of the drive shaft shown in the embodiments utilizing universal joints ( FIG. 5   c ). The inclined drive shaft  3 ,  4  is then mounted in bearings at the first transmission  13  and at the second transmission  17 . According to this variant the drive shaft  3 ,  4  is run by means of a gear wheel at the drive unit  8 . Said gear wheel at the drive unit transfers rotational motion to the drive shaft  3 ,  4  through a conical gear wheel mounted on drive shaft  3 ,  4 . At the second transmission the drive shaft  3 ,  4  transfers, in turn, rotational motion to the shorter part of drive shaft  3 ,  4  by means of a conically shaped gear wheel at the outer end of the inclined longer part of drive shaft  3 ,  4 . The shorter part of drive shaft  3 ,  4  is mounted in bearing in the same way as in the example shown in  FIG. 5   a . Also in this embodiment, one or both arms  6 ,  7  can be provided with this type of power transfer, i.e. an inclined shaft may be mounted in bearings at both transmissions  13 ,  17 . 
     While the preferred embodiment and various alternative embodiments of the invention have been disclosed and described in detail herein, it may be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope thereof.