Patent Publication Number: US-8540841-B2

Title: Rubber sheet jointing apparatus and method

Description:
INCORPORATION BY REFERENCE 
     This application is a divisional of U.S. Ser. No. 11/443,183, filed May 31, 2006, and is based on and claims priority under 35 U.S.C. 119 with respect to Japanese Applications No. 2005-165041 filed on Jun. 6, 2005 and No. 2005-226908 filed on Aug. 4, 2005. The entire contents of these three applications are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention: 
     The present invention relates to a rubber sheet joining apparatus and method for joining the end surfaces of one or two rubber sheets with each other by butt joint. In particular, it relates to a rubber sheet joining apparatus and method capable of manufacturing a jointed plane rubber sheet or a round or endless rubber band easily and efficiently without making any bulge at the jointed portion thereof. 
     2. Discussion of the Related Art: 
     Generally, for vehicular tires, inner liners which are composite rubber sheets made from rubber only and body or carcass plies, belts and the like which are rubber sheets reinforced by fibers or steel cords are often used by jointing end surfaces of rubber sheet strips. For example, the rubber sheet for a body ply, a belt or the like having a predetermined length can be manufactured by making by a calendar rolling machine a roll of a long rubber textile or cloth having numerous cords embedded in the rubber layer, then by uncoiling and cutting the roll of the long rubber cloth which has the cords arranged parallel in the longitudinal direction thereof, to those sheet strips of the length corresponding to the width of the body ply or the belt which width depends on the kind and dimension of the tire to be manufactured, and further, by mutually jointing the end edges parallel to the cords of those rubber sheet stripes so cut. 
     Used generally for jointing end edges of two adjoining sheets are two methods called “lap joint” and “butt joint”. The lap joint can be performed by lapping an end edge of a second sheet on an end edge of a first sheet and then, by applying a pressure on a jointed area including the lapped area. 
     In the lap joint method, since the thickness of the rubber sheet at the lapped joint area becomes as twice the thickness of other areas, doubled are not only the thickness of the rubber sheet, but also the number of the reinforcing cords in the case of a fiber or steel cord reinforced rubber sheet. Thus, the thickness of the jointed rubber sheet dose not become uniform and the difference in rigidity becomes large, so that the uniformity of the tire is degraded. For this reason, the use of the lap joint method tends to decrease these days. 
     On the other hand, the butt joint can be performed by thrusting the end edge of one sheet against the end edge of the other sheet and then, by pressuring them to be firmly jointed by mechanical or physical means. Thus, a bulge is generated at the jointed portion. 
     That is, as described in Japanese Unexamined Published Patent Application No. 2004-142219, since the both end edges of first and second sheets are jointed as being drawn to come closer to each other by a pair of rollers each taking a bevel wheel shape, the bulge is generated on the jointed portion. 
     In order to level out the bulge on the jointed portion, the technology described in the foregoing Japanese application is designed to heighten the flatness at the jointed portion by adding as a step subsequent to the sheet jointing a leveling or smoothening step of pressing down the jointed portion by upper and lower leveling plates including warming means with the jointed portion being put therebetween from upper and lower sides. 
     However, in the technology described in the foregoing Japanese application, the flatness on the jointed portion is obtained by chemically changing the quality of the rubber by the use of the upper and lower leveling plates including the warming means. Thus, the jointed portion and other portions of the sheet become the same in thickness, but different in quality. Therefore, where tires are manufactured using sheets each jointed by the foregoing jointing method, it results that a portion which is not uniform in physical property with other portions is present on the circumference of the tire, and this causes an obstruction in enhancing the tire quality. In addition, the addition of the smoothening step causes not only an increase in the cost of the manufacturing facilities, but also an elongation in the manufacturing cycle time. 
     Further, as described in Japanese Unexamined Published Patent Application No. 2002-11805, there has also been known a jointing apparatus and method for butt-jointing the circumferential opposite end portions of an unvulcanized rubber sheet blank such as carcass or body ply used as tire component blank or the like on a shaping drum. In the apparatus and method described in the Japanese application, a belt-like rubber blank cut to a predetermined length is wound on the circumferential surface of the shaping drum to cling thereto with jointing portions of the shaping drum held opened, and joint end portions of the belt-like rubber blank are drawn toward each other to be temporarily jointed by closing or diametrically contracting the shaping drum, in which state the joint end portions are pressure-jointed by a pair of rollers each taking a bevel wheel shape. 
     In the last mentioned apparatus and method, since the joint end portions of the belt-like shape rubber blank are jointed as they are made by the rollers of the bevel wheel shape to come close to each other, it necessarily results that the jointed portion has a bulge thereon and is degraded in flatness. Accordingly, in order to level out the bulge on the jointed portion, it becomes necessary to heighten the flatness at the jointed portion by adding as a step subsequent to the sheet jointing a smoothening step of pressing down the jointed portion by leveling plates including warming means with the jointed portion being put therebetween from upper and lower sides, as described in the first mentioned Japanese application. 
     As described above, in the last mentioned apparatus and method, in order to level out the bulge on the jointed portion, it is required to improve the flatness by chemically degenerating the rubber by the use of the leveling plates including warming means, as described in the first mentioned Japanese application. Accordingly, where tires are manufactured using carcass or body plies each jointed by the last mentioned jointing apparatus and method, each tire would have at the circumferential portion thereof a portion which lacks uniformity because of being different in physical property, thereby making an obstruction in improving the tire quality. In addition, the addition of the smoothening step undesirably causes not only an increase in the cost for tire manufacturing facilities but also an elongation in the manufacturing cycle time. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide an improved jointing apparatus and method for jointing end surfaces of two joint end portions of at least one rubber sheet to have a jointed portion which does not have any bulge thereon and which is uniform in thickness as well as in quality. 
     Another object of the present invention is to provide an improved jointing apparatus and method of the character set forth above which is particularly designed for manufacturing plane rubber sheet blanks. 
     A further object of the present invention is to provide an improved jointing apparatus and method of the character set forth above which is particularly designed for manufacturing round or endless rubber sheet blanks. 
     A still further object of the present invention is to provide an improved jointing apparatus and method of the character set forth above which is particularly designed for continuously performing the jointing of a plurality of rubber sheet strips to manufacture an elongated rubber sheet batch and the jointing of opposite end portions of the elongated rubber sheet batch to manufacture a round or endless rubber band within a single rubber sheet joining apparatus. 
     According to one aspect of the present invention, there is provided a rubber sheet jointing apparatus for jointing end surfaces of two joint end portions of at least one rubber sheet by butt joint. The apparatus comprises first holding means for releasably holding one of the two joint end portions; second holding means provided movably relative to the first holding means for releasably holding the other of the two joint end portions; and operating means for pressure-contacting end surfaces of the two joint end portions respectively held by the first and second holding means by effecting relative movement between the first and second holding means. Mutually facing surfaces of the first and second holding means are respectively provided with holder portions which are able to overlap to mesh with each other. 
     With this construction, since the holder portions which are able to overlap to mesh with each other are provided on the mutually facing surfaces of the first and second holding means for respectively holding the two joint end portions to be jointed with each other, the jointing of the joint end surfaces with each other can be realized with the entire parts of the two joint end portions being held steadily. Thus, even when the two joint end portions of the at least one rubber sheet are pressure-joined with a strong pressuring force, any bulge can be prevented from occurring on the jointed portion. Therefore, it can be realized to easily manufacture a plane rubber sheet blank or a round rubber sheet blank which is uniform in thickness and excellent in flatness at the jointed portion. In addition, because no heat is applied to the rubber sheet, the same does not deteriorate in quality, so that it can be realized to easily obtain the plane rubber sheet blank or a round rubber sheet which is uniform also in quality at the jointed portion. 
     According to another or second aspect of the present invention, there is provided a rubber sheet jointing method of jointing end surfaces of two joint end portions of at least one rubber sheet by butt joint. The method comprises the steps of providing first and second holding means which are able to overlap to mesh with each other at mutually facing surfaces thereof; making one of the first and second holding means hold one of the two joint end portions and making the other of the first and second holding means hold the other of the two joint end portions; and relatively moving the first and second holding means to a position where the first holding means partly overlap with the second holding means through the meshing engagement at the mutually facing surfaces of the first and second holding means, to joint through pressuring contact the end surface of one of the two joint end portions being held by the first holding means with the other joint end portion being held by the second holding means. 
     With the construction in the second aspect, the first holding means for holding one of the two joint end portions and the second holding means for holding the other of the two joint end portions are relatively moved to the position where they overlap with each other, to joint the two joint end portions of at least one rubber sheet. Thus, even when the two joint end portions are pressure-joined with a strong pressuring force, any bulge can be prevented from occurring on the jointed portion. This makes it unnecessary to perform a leveling or smoothening step of rolling or leveling any bulge which would otherwise be formed on the jointed portion after the jointing step. Accordingly, it can be realized to efficiently manufacture a plane rubber sheet blank or a round or endless rubber sheet blank which is uniform in thickness and excellent in flatness at the jointed portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects and many of the attendant advantages of the present invention may readily be appreciated as the same becomes better understood by reference to the preferred embodiments of the present invention when considered in connection with the accompanying drawings, wherein like reference numerals designate the same or corresponding parts throughout several views, and in which: 
         FIG. 1  is a plan view of a rubber sheet jointing apparatus in a first embodiment according to the present invention; 
         FIG. 2  is an enlarged side view of the apparatus as viewed in the direction A in  FIG. 1 ; 
         FIG. 3  is an enlarged elevational view of the apparatus as viewed in the direction B in  FIG. 2 ; 
         FIG. 4  is a fragmentary view showing a portion C shown in  FIG. 2  in detail in an exaggerated scale; 
         FIG. 5  is a fragmentary view taken along a line D-D in  FIG. 4  for showing rugged portions which are able to mesh with each other, in a further exaggerated scale; 
         FIG. 6  is a view similar to  FIG. 2  showing the apparatus in a state that a first rubber sheet has been supplied; 
         FIG. 7  is a view similar to  FIG. 2  showing the apparatus in another state that the apparatus holds two rubber sheets; 
         FIG. 8  is a view similar to  FIG. 2  showing the apparatus in still another state that the two rubber sheets have been jointed; 
         FIG. 9  is a view similar to  FIG. 2  showing the apparatus in a further state that the jointed rubber sheet is sent out by a predetermined distance; 
         FIG. 10  is an explanatory view showing a feeding state of a ribbon; 
         FIG. 11  is a plan view of a rubber sheet jointing apparatus in a second embodiment according to the present invention; 
         FIG. 12  is an explanatory view showing a feeding state of a ribbon in the second embodiment; 
         FIG. 13  is a plan view of a rubber sheet jointing apparatus in a third embodiment according to the present invention; 
         FIG. 14  is a side view of the apparatus shown in  FIG. 13 ; 
         FIG. 15  is a front view of a rubber sheet jointing device incorporated in the apparatus; 
         FIG. 16  is a side view of the rubber sheet jointing device as viewed in the direction A in  FIG. 15 ; 
         FIG. 17  is a longitudinal sectional view of a shaping drum taken along the line B-B in  FIG. 15 ; 
         FIG. 18  is a plan view of a part of the external surface of the shaping drum as viewed in the direction C in  FIG. 16 ; 
         FIG. 19  is a bottom view of a part of the rubber sheet jointing device as viewed in the direction D in  FIG. 15 ; 
         FIG. 20  is a sectional view of the rubber sheet jointing device taken along the line E-E in  FIG. 15 ; 
         FIG. 21  is a fragmentary view showing the operational state of a part of the rubber sheet jointing device in an exaggerated scale; 
         FIG. 22  is a plan view of a rubber sheet jointing apparatus in a fourth embodiment according to the present invention; 
         FIG. 23  is an enlarged side view of the apparatus as viewed in the direction E in  FIG. 22 ; 
         FIG. 24  is a plan view showing hands of a robot in the fourth embodiment according to the present invention; 
         FIG. 25  is a rear view of the robot hands as viewed in the direction F in  FIG. 24 ; and 
         FIG. 26  is a side view similar to that shown in  FIG. 23  with the apparatus being in a different state of operation. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     (First Embodiment) 
     Hereinafter, with reference to the accompanying drawings, description will be made regarding a first embodiment wherein the present invention is practiced for manufacturing fiber-reinforced plane rubber sheet blanks for tire body plies. For convenience in description, a vertical direction, a left-right horizontal direction and a front-rear horizontal direction in  FIG. 2  will be referred to as a Z-axis direction, a Y-axis direction and an X-axis direction respectively, and the left and right in  FIG. 2  will be referred to as the front side and the rear side in the Y-axis direction, respectively. 
     Referring now to  FIGS. 1 through 3 , a rubber sheet jointing apparatus  10  for jointing the end surfaces of two rubber sheets S is arranged at a butt joint station  2   st . The jointing apparatus  10  is provided with a support table  12 , which is horizontally arranged on the factory floor through leg portions  11  thereof. The support table  12  has a pair of support pillars  13 ,  14  upstanding with a predetermined space therebetween. The upper ends and the lower ends of the pair of support pillars  13 ,  14  are connected with respective crossbeams  15 ,  16 , whereby a fixed frame  17  is constituted by the support pillars  13 ,  14  and the crossbeams  15 ,  16 . 
     Mounting bases  19 ,  20  each extending in the X-axis direction are fixed respectively on the crossbeams  15 ,  16  of the fixed frame  17 , and the mounting bases  19 ,  20  are respectively provided with first holding means  21  for holding one of two rubber sheets S which are to be jointed with each other, and a second holding means  22  which is movable relative to the first holding means  21  in the horizontal Y-direction while holding the other of the two rubber sheets S. 
     The first holding means  21  is provided with a pair of first holders  23 ,  24  which are movable to and from each other in the vertical direction. The pair of first holders  23 ,  24  are vertically movably guided respectively along upper and lower linear guides  25 ,  26  arranged in the vertical direction and are vertically opened and closed by first cylinder actuators  29 ,  30  in a synchronous relation. 
     That is, guide blocks  25   b  for the upper linear guides  25  are arranged at the opposite ends in the X-axis direction of the upper mounting base  19 , and the guide blocks  25   b  vertical slidably guide rails  25   a  respectively. The rails  25   a  attach thereto connection blocks  27 , which are connected respectively to the opposite end portions of the first holder  23  on the upper side. 
     Similarly, guide blocks  26   b  for the lower linear guides  26  are arranged at the opposite ends in the X-axis direction of the lower mounting base  20 , and the guide blocks  26   b  vertical slidably guide rails  26   a  respectively. The rails  26   a  attach thereto connection blocks  28 , which are connected respectively to the opposite end portions of the first holder  24  on the lower side. 
     The first cylinder actuators  29 ,  30  are arranged respectively at center portions in the X-axis direction of the mounting bases  19 ,  20 , and piston rods of the first cylinder actuators  29 ,  30  are connected respectively to the upper end of the first holder  23  on the upper side and the lower end of the first holder  24  on the lower side. Thus, the pair of first holders  23 ,  24  can be opened and closed vertically by the first cylinder actuators  29 ,  30 . 
     As shown in  FIGS. 4 and 5  in detail, rugged portions  31   a ,  32   a  each taking a comb tooth shape of a predetermined depth are formed at respective end portions (the left end portions as viewed in  FIG. 2 ) of holder portions  31 ,  32  which are defined as holder ends of the pair of first holders  23 ,  24 , and are able to partly overlap with those of a pair of second holders, as referred to later. Mutually facing ends in the vertical direction of the holder portions  31 ,  32  cooperate to hold the joint end portion of the rubber sheet S at a position retracted by an amount L 1  from the end surfaces of the rugged portions  31   a ,  32   a . The predetermined depth of the rugged portions  31   a ,  32   a  is set to be deeper than the amount L 1 , as referred to later in detail. Further, as shown in  FIG. 4 , the mutually facing surfaces at which the holder portions  31 ,  32  are brought into contact with the rubber sheet S have formed thereon wave claws  31   b ,  32   b  such as, e.g., saw tooth claws of a minute height which bite the upper and lower surfaces of the rubber sheet S, so that the rubber sheet S does not retract relative to the holder portions  31 ,  32  during the jointing operation. 
     The horizontal lengths of the holder portions  31 ,  32  in the X-axis direction is designed to be longer than the length LB (refer to  FIG. 10 ) of the rubber sheet S, and when the operations of the first cylinder actuators  29 ,  30  cause the first holders  23 ,  24  to come closer to each other, the holder portions  31 ,  32  can hold the rubber sheet S therebetween over the entire length of the rubber sheet S. 
     On the other hand, the second holding means  22  is provided with a pair of second holders  41 ,  42  which are vertically movable to and from each other. The pair of second holders  41 ,  42  are connected to the connection blocks  27 ,  28  through upper linear guides  43  and lower linear guides  44  which are arranged horizontally in the Y-axis direction. Therefore, the pair of second holders  41 ,  42  can be opened or closed bodily with the opening or closing motion of the pair of first holders  23 ,  24 . 
     That is, the pair of second holders  41 ,  42  are provided on the rails  43   a ,  44   a  of the upper and lower linear guides  43 ,  44  to face the first holders  23 ,  24  in the Y-axis direction, respectively. The rails  43   a ,  44   a  are guided by the guide blocks  43   b ,  44   b  provided on the connection blocks  27 ,  28 , to be slidable in the horizontal Y-axis direction. 
     The connection blocks  27 ,  28  are provided with second cylinder actuators  47 ,  48 , whose piston rods are connected to the pair of second holders  41 ,  42 . Therefore, the pair of second holders  41 ,  42  are bodily moved in the horizontal direction by the synchronous motions of the second cylinder actuators  47 ,  48 , so that the second holders  41 ,  42  are moved relative to the first holders  23 ,  24  in the Y-axis direction. The second cylinder actuators  47 ,  48  constitute operating means in the claimed invention. 
     As shown in  FIGS. 4 and 5  in detail, rugged portions  45   a ,  46   a  each taking a comb tooth shape of the aforementioned predetermined depth are formed at end portions (the right end portions as viewed in  FIG. 2 ) of holder portions  45 ,  46  which are defined as holder ends of the pair of second holders  41 ,  42  respectively facing the first holders  23 ,  24 . The rugged portions  45   a ,  46   a  are able to partly overlap with those of the pair of first holders  23 ,  24 . Mutually facing ends in the vertical direction of the holder portions  45 ,  46  cooperate to hold the joint end portion of another rubber sheet S (which will be referred to as “second rubber sheet S” only for the sake of distinction from the rubber sheet S being held by the first holders  23 ,  24 ) to be jointed with the first mentioned rubber sheet S, at a position retracted by the aforementioned amount L 1  from the end surfaces of the rugged portions  45   a ,  46   a . The predetermined depth of the rugged portions  45   a ,  46   a  is set to be deeper than the amount L 1 . Further, as shown in  FIG. 4 , the mutually facing surfaces at which the holder portions  45 ,  46  are brought into contact with the second rubber sheet S have formed thereon wave claws  45   b ,  46   b  such as, e.g., saw tooth claws of the aforementioned minute height which bite the upper and lower surfaces of the second rubber sheet S, so that the second rubber sheet S does not retract relative to the holder portions  45 ,  46  during the jointing operation. 
     As best shown in  FIG. 5 , the rugged portions  45   a ,  46   a  formed on the side of the pair of second holders  41 ,  42  are arranged to face their concave portions with the convex portions of the rugged portions  31   a ,  32   a  formed on the side of the pair of first holders  23 ,  24 , so that as mentioned earlier, the rugged portions  45   a ,  46   a  can complementarily be meshed respectively with the rugged portions  31   a ,  32   a . Therefore, the first holders  23 ,  24  and the second holders  41 ,  42  partly overlap with each other through intermeshing of the comb-tooth shape rugged portions  31   a ,  32   a  with the comb-tooth shape rugged portions  45   a ,  46   a . The horizontal length of the holder portions  45 ,  46  in the X-axis direction is also designed to be longer than the aforementioned length LB of the rubber sheet S, so that the holder portions  45 ,  46  can hold the second rubber sheet S therebetween over the entire length of the second rubber sheet S. 
     Rails  51   a  of parallel linear guides  51  (one only shown in  FIG. 2 ) extending in the Y-axis direction are fixed on the support table  12  behind the fixed frame  17 , and a movable table  52  is guided on the rails  51   a  through guide blocks  51   b  of the liner guides  51  to be movable in the Y-axis direction. The movable table  52  has a vertical frame  53  upright therefrom, on which feeding means  54  is provided for holding and feeding the rubber sheet S (i.e., one rubber sheet or a batch of two or more jointed rubber sheets) by a predetermined amount whenever operated. 
     The feeding means  54  is provided with a pair of third holders  55 ,  56  which are vertically movable to and from each other. The pair of third holders  55 ,  56  are respectively connected to third cylinder actuators  57 ,  58  mounted on the vertical frame  53  and are vertically opened and closed by the third cylinder actuators  57 ,  58 . The pair of third holders  55 ,  56  pass through the fixed frame  17  and extend their ends (i.e., their front ends) to a position where the delivery of the rubber sheet S can be done between the first holders  23 ,  24  and themselves. The third cylinder actuators  57 ,  58  serve as second operation means recited in the claimed invention. 
     A ball screw shaft  61  is supported under the support table  12  to be rotatable about an axis parallel to the Y-axis direction and is screw-engaged with a ball nut  62  fixed on the lower surface of the movable table  52 . The ball screw shaft  61  is connected to a motor shaft of an electric motor  63  mounted on the support table  12 , so that upon operation of the electric motor  63 , the movable table  52  is controllably moved through the ball screw shaft  61  and the ball nut  62  in the Y-axis direction. 
     Components which respectively movably guide and support the first holding means  21  and the second holding means  22  are arranged to be vertically symmetrical as viewed in  FIG. 3 . However, in order that the constructions of the first holding means  21  and the second holding means  22  become easier to understand,  FIG. 2  is drawn by omitting at the upper half the cylinder actuator  47  for moving the second holder  41  arranged on the upper side and by omitting at the lower half the liner guide  26 , the connection block  28 , the first cylinder actuator  30  and the like which are provided for guiding the first holder  24  on the lower side. 
     As shown in  FIG. 10 , the foregoing rubber sheet S is made by cutting a ribbon R of a predetermined width LA which is scrolled around a bobbin B, to those strips of the aforementioned predetermined length LB which corresponds to a ply width which is determined in dependence on the kind, size and the like of the tires to be manufactured. The cutting is performed at right angles to the cords C embedded in each of those strips. The ribbon R is constituted by rubber-coating a plurality of fiber cords made of, e.g., polyester. The fiber cords C are placed under a dipping process for better property of adhesiveness with rubber. Although not shown, the rubber coating of the fiber cords C can be done by causing the fiber cords C to pass through an unvulcanized compound rubber layer which is extruded by a small extruding machine. 
     As shown in  FIGS. 1 and 10 , a cutting station  1   st  for cutting the ribbon R to those strips of the predetermined length LB is arranged to be next to the butt joint station  2   st . The cutting station  1   st  is provided with supply means  70  for holding and supplying the ribbon R fed from the bobbin B, to the butt joint station  2   st  and cutting means  80  for cutting the ribbon R to those strips of the predetermined length LB corresponding to the ply width LB at right angles to the cords C. Rectangular or elongated rubber sheets S each having the width LA and the length LB are made by the cutting means  80  and are successively supplied by the supply means  70  to the butt joint station  2   st . In this first embodiment, the elongated rubber sheets S are jointed in succession one after another at their side end edges extending in the lengthwise direction thereof, as best illustrated in  FIG. 10 , as described hereunder. 
     (Operation) 
     The operation of the first embodiment as constructed above will be described hereafter. In the following description of the operation, for better understanding, each rubber sheet S supplied to the second holding means  22  will be called “rubber sheet strip” whereas an aggregation of plural jointed rubber sheets S will be called “rubber sheet group or batch”. 
     First of all, the end portion of the ribbon R in which the fiber cords are embedded in a rubber layer of the predetermined width LA is led to the cutting station  1   st  and is cut by the cutting means  80  to a rubber sheet strip S of the predetermined length (the body ply width) LB which is determined in dependence on the kind, size and the like of the tires to be manufactured. The rubber sheet strip S cut to the predetermined length LB is supplied by the supply means  70  to the butt joint station  2   st  (refer to  FIGS. 1 and 10 ). 
     When the first rubber sheet strip S is supplied to the butt joint station  2   st  with its left side portion being held by the supply means  70  as viewed in  FIG. 2 , the electric motor  63  is driven, and the rotation of the electric motor  63  controllably moves the movable table  52  through the ball screw shaft  61  and the ball nut  62  from the original position toward the second holder means  22  in the Y-axis direction. Thus, as shown in  FIG. 6 , the movable table  52  is advanced to the position where the third holders  55 ,  56  can hold the right side portion of the rubber sheet strip S whose left side portion is being held by the supply means  70 . In this state, the third holders  55 ,  56  are moved by the third cylinder actuators  57 ,  58  mounted on the movable table  52  to come close to each other, whereby the third holder  55 ,  56  hold the right side portion of the first rubber sheet strip S. 
     Only when the very first rubber sheet strip S is supplied in this way, the third holders  55 ,  56  remain vacant without holding any rubber sheet strip S and therefore, the movable table  52  is controllably moved so that the third holders  55 ,  56  go to fetch the supplied rubber sheet strip S directly. 
     When the right side portion of the rubber sheet strip S is held by the third holders  55 ,  56 , the left side portion of the rubber sheet strip S is released from the holding by the supply means  70 , in which state the electric motor  63  is driven in a direction opposite to the foregoing operation to retract the movable table  52  in the Y-axis direction. The movable table  52  is retracted to the position shown in  FIG. 2  where the first holders  23 ,  24  can hold the joint end portion (the left side portion as viewed in  FIG. 4 ) of the rubber sheet strip S whose right side portion being still held by the third holders  55 ,  56 . Thus, a joint end surface S 1  (shown in  FIG. 10 ) of the first rubber sheet strip S is positioned to a position which recedes the slight amount (L 1 ) in the Y-axis direction from the end surfaces of the comb-tooth shape rugged portions  31   a ,  32   a  of the first holders  23 ,  24 . 
     Then, a second rubber sheet strip S cut to the predetermined length LB in the same manner as aforementioned is supplied to the butt joint station  2   st . A joint end surface S 1  (the right end surface as viewed in  FIG. 4 ) of the second rubber sheet strip S supplied to the butt joint station  2   st  is thus placed between the second holders  41  and  42  and is positioned to the position where it recedes by the slight amount (L 1 ) in the Y-axis direction from the right end surfaces of the comb-tooth shape rugged portions  45   a ,  46   a  of the second holders  41 ,  42 . In this state, the first cylinder actuators  29 ,  30  are operated, and the first holders  23 ,  24  are vertically moved to come close toward each other while being guided along the linear guides  25 ,  25  in the Z-axis direction. Thus, the upper and lower surface of the joint end portion of the first rubber sheet strip S being held by the third holders  55 ,  56  are held (pinched) by the holder portions  31 ,  32  of the first holders  23 ,  24 . It results from this that the first rubber sheet strip S is held by the holding portions  31 ,  32  at the position where the joint end surface S 1  recedes by the slight amount (L 1 ) in the Y-axis direction from the end surfaces of the comb-tooth shape rugged portions  31   a ,  32   a  of the first holders  23 ,  24 , as indicated by the phantom line in  FIG. 4 . 
     As the first holders  23 ,  24  are vertically moved to come close to each other, the second holders  41 ,  42  are vertically moved bodily with the first holders  23 ,  24  through the connection blocks  27 ,  28  and the second cylinder actuators  47 ,  48  to come close to each other. Thus, the upper and lower surface of the joint end portion (i.e., the right end portion as viewed in  FIG. 4 ) of the second rubber sheet strip S whose left side portion being still held by the supply means  70  are held (pinched) by the holder portions  45 ,  46  of the second holders  41 ,  42 . Also in this case, the second rubber sheet strip S is held by the holder portions  45 ,  46  at the position where the joint end surface S 1  (i.e., the right end surface) recedes by the slight amount (L 1 ) in the Y-axis direction from the end surfaces of the comb-tooth shape rugged portions  45   a ,  46   a  of the second holders  41 ,  42 , as indicated by the phantom line in  FIG. 4 . 
     When the two rubber sheet strips S are held respectively between the first holders  23  and  24  and between the second holders  41  and  42  as shown in  FIG. 7 , the third holders  55 ,  56  are operated to open by the third cylinder actuators  57 ,  58  and the second rubber sheet strip S is released from the holding by the supply device  70 . 
     Subsequently, the second cylinder actuators  47 ,  48  are operated, and the second holders  41 ,  42  are horizontally moved toward the first holders  23 ,  24  while being guided by the linear guides  43 ,  44  in the Y-axis direction until the rugged portions  45   a ,  46   a  of the comb tooth shape formed on the second holders  41 ,  42  are respectively brought into complementary meshing with the rugged portions  31   a ,  32   a  of the comb tooth shape formed on the first holders  23 ,  24 . In this way, as the rugged portions  45   a ,  46   a  of the comb tooth shape on the side of the second holders  41 ,  42  are complementarily entered into the rugged portions  31   a ,  32   a  of the comb tooth shape on the side of the first holders  23 ,  24  to a predetermined depth, the joint end surface S 1  of the second rubber sheet strip S being held by the holder portions  45 ,  46  on the side of the second holders  41 ,  42  is pressured on and contacted with the joint end surface S 1  of the first rubber sheet strip S being held by the holder portions  31 ,  32  on the side of the first holders  23 ,  24 . 
     The stroke end of the second cylinder actuators  47 ,  48  has been set to give the both rubber sheet strip S a predetermined (e.g., one millimeter or so) pressuring allowance (ΔL). That is, the second holders  45 ,  46  are partly overlapped respectively with the first holders  23 ,  24  so that the rugged portions  45   a ,  46   a  of the comb tooth shape on the second holders  45 ,  46  are complementarily meshed with the rugged portions  31   a ,  32   a  of the comb tooth shape on the first holders  23 ,  24  to a predetermined depth of L 1 +ΔL. Thus, both rubber sheet strip S are pressured on each other through the distance of the predetermined pressuring allowance (ΔL), and thus, the joint end surfaces S 1  can be pressure-contacted with each other with a strong pressure force in the state that the joint end portions of the both rubber sheet strips S are being held steadily, whereby the both rubber sheet strips S can be jointed reliably. 
     Because the second holders  41 ,  42  can respectively overlap with the first holders  23 ,  24  through the mutual meshing between the comb-tooth shape rugged portions  31   a ,  32   a  and the comb-tooth shape rugged portions  45   a ,  46   a , it becomes possible to pressure-contact the joint end surfaces S 1  of the both rubber sheet strips S with the strong pressuring force with the respective joint end portions of the both rubber sheet strips S being steadily held by the respective holder portions  31 ,  32 ,  45 ,  46  of the first and second holders  23 ,  24 ,  41 ,  42 . Accordingly, the joint end portions can be prevented from having any bulge thereon, and the flatness at the joint end portions can be improved. Further, since any bulge does not occur, it becomes unnecessary to roll or smoothen the bulge portion with heat being applied to the rubber sheet strips S, so that the rubber sheet strips S can be kept uniform in quality without being degenerated. 
     In this manner, the second cylinder actuators  47 ,  48  are operated to their stroke ends, and the joint end surfaces S 1  of the both rubber sheet strips S are pressure-contacted to be jointed with each other. Then, the third holders  55 ,  56  are moved by the third cylinder actuators  57 ,  58  to come close to each other, whereby the jointed rubber sheet batch S can be held at the right side portion of the first rubber sheet strip S. At the same time, the first cylinder actuators  29 ,  30  are operated, whereby the first holders  23 ,  24  and the second holders  41 ,  42  are vertically moved to open while being guided along the linear guides  25 ,  26  in the Z-axis direction, thereby to release the rubber sheet batch S from the holding thereby. 
     Upon the releasing of the rubber sheet batch S from the holding by the first holders  23 ,  24  and the second holders  41 ,  42 , the electric motor  63  is operated to retract the third holders  55 ,  56  together with the movable table  52  by a stroke (LA) corresponding to the width dimension of the rubber sheet piece S in the Y-axis direction. Thus, since the rubber sheet batch S being held by the third holders  55 ,  56  is retracted by the width dimension (LA) of the rubber sheet piece S in the Y-axis direction as shown in  FIG. 9 , it results that a new or next joint end surface S 1  of the rubber sheet batch S is positioned to the position where it recedes by the slight amount L 1  in the Y-axis direction from the end surface of the comb-tooth shape rugged portions  31   a ,  32   a  on the first holders  23 ,  24 . 
     When a third rubber sheet strip S is then supplied between the second holders  41  and  42  in the same manner as the foregoing operation, the third rubber sheet strip S is held by the second holders  41 ,  42 , and at the same time, the rubber sheet batch S composed of the plural jointed rubber sheet strips S is held by the first holders  23 ,  24 . In this state, the second holders  41 ,  42  are moved toward the first holders  23 ,  24  in the Y-axis direction, whereby in the same manner as described above, the joint end surface S 1  of the third rubber sheet strip S is pressure-contacted with the joint end surface S 1  of the rubber sheet batch S thereby to joint both of them together. 
     During the jointing step of the rubber sheet strips S, the movable table  52  is advanced by the operation of the electric motor  63  by the stroke corresponding to the width dimension LA of the rubber sheet strip S in the Y-axis direction to feed the third holders  55 ,  56  to the position shown in  FIG. 8  by the predetermined amount (LA) relative to the rubber sheet batch S. It result from this that the third holders  55 ,  56  can come to hold the rubber sheet batch S at the position which has a predetermined relation with the next joint end surface S 1  of the rubber sheet batch S at all times. That is, by retracting the third holders  55 ,  56  holding the rubber sheet batch S by the width dimension LA of the rubber sheet strip S in the Y-axis direction, it becomes possible to position the next joint end surface S 1  of the rubber sheet batch S to the predetermined position at all times. 
     By repetitively performing the foregoing operation, rubber sheet strips S are successively jointed to one end surface of the rubber sheet batch S. When the rubber sheet batch S of a predetermined length (N×LA) corresponding to the body ply for one tire is manufactured by using the rubber sheet strips S of a predetermined number (N), the rubber sheet butch S (i.e., plane body ply sheet) is pulled by sheet drawing means (not shown) from between the third holders  55 ,  56 . Thereafter, the rubber sheet butch S is placed on a tray (not shown) and is transferred onto a tire shaping drum of another jointing apparatus (not shown) which will be described as a third embodiment of the present invention later. 
     It is to be noted that the body ply sheet S using the ribbon R may be manufactured by using a ribbon which has been prepared in advance or may be manufactured as the step to follow a step at which the ribbon R is manufactured in a parallel time relation. 
     (Second Embodiment) 
       FIGS. 11 and 12  show a second embodiment according to the present invention, which exemplifies the manufacturing of sheets for belts of automotive tires with steel cords embedded therein. 
     A jointing apparatus  100  in this second embodiment uses a ribbon R of a predetermined width LA in which plural number of steel cords each made by intertwisting plated wires are rubber-coated by being made to pass through an unvulcanized composite rubber layer which is extruded from a die of a rubber extruding machine (not shown). The ribbon R sent out from a bobbin B is successively cut by cutting means  80  arranged at a cutting station  1   st , to those strips S of a predetermined length LB which corresponds to a belt width determined by the specification of the tires to be manufactured. The cutting angle at which the ribbon R is cut coincides with a belt angle which is inclined at a predetermined angle with the cords C which are arranged in parallel with the longitudinal direction of the ribbon R. Each rubber sheet strip S so cut is supplied by supply means  70  to a butt joint station  2   st  and is placed between a pair of second holders  41 ,  42  (reference numeral  42  not shown) of second holding means  22  to be held thereby. In this state, in the same manner as described in the foregoing first embodiment, the second holders  41 ,  42  are moved relative to a pair of first holders  23 ,  24  (reference numeral  24  not shown) of first holding means  21  in the Y-axis direction (in the upper-lower direction as viewed in  FIG. 11 ) and are advanced to a position where comb-tooth shape rugged portions  45   a  ( 46   a  not shown) of the second holders  41 ,  42  are brought into meshing respectively with comb-tooth shape rugged portions  31   a  ( 32   a  not shown) of the first holders  23 ,  24 . Thus, a joint end surface S 1  of a rubber sheet strip S being held by the second holders  41 ,  42  is pressure-contacted with a joint end surface S 1  of another rubber sheet strip S or a rubber sheet batch S being held by the first holders  23 ,  24  thereby to join the rubber sheet strip S with said another rubber sheet strip S or with the rubber sheet batch S. 
     Third holders  55 ,  56  (reference numeral  56  not shown) holding the jointed rubber sheet batch S are movable in the Y-axis direction as well as in an X-axis direction (the left-right direction as viewed in  FIG. 11 ) so that the rubber sheet batch S can be sent out along a predetermined angle inclined relative to the axes of the cords C. Therefore, each time a rubber sheet strip S is jointed, the third holders  55 ,  56  are moved by the width dimension LA of the rubber sheet strip S in the Y-axis direction and at the same time, by a distance depending on the inclination angle in the X-axis direction, whereby the joint end surface S 1  of the rubber sheet batch S can be positioned to a predetermined position at all times. 
     In this way, a plane belt sheet of the predetermined width for one tire is manufactured and is placed by sheet drawing means (not shown) on a tray to be transferred to a shaping drum such as that referred to in the following third embodiment of the present invention. 
     Each of the aforementioned embodiments describes the example wherein jointing is performed between the body ply sheets each having the fiber cords embedded in the rubber sheet strip S or between the tire belt sheets each having the steel cords embedded in the rubber sheep strip S. However, the jointing apparatus and method according to the present invention is applicable to the manufacturing of a composite rubber sheet which is constituted by jointing rubber sheet strips each not having any cord embedded therein. 
     Of course, the specific constructions, support structures and operations of the first holding means  21  and the second holding means  22  described in the foregoing embodiments are not limited to those described in the foregoing embodiments and may take various forms without departing from the gist of the present invention. 
     As described hereinabove, in the foregoing embodiments, since the holder portions  31 ,  32 ,  45 ,  46  which are able to overlap to mesh with each other are provided on the mutually facing surfaces of the first and second holding means  21 ,  22  for respectively holding the joint end portions of the two rubber sheets S to be jointed with each other, the jointing of the joint end surfaces S 1  with each other can be realized with the joint end portions of the two rubber sheets S being held over the entire parts thereof. Thus, even when the both rubber sheets S are pressure-joined with a strong pressuring force, any bulge can be prevented from occurring on the jointed portion. Therefore, it can be realized to easily manufacture rubber sheet blanks which are uniform in thickness and excellent in flatness. In addition, because no heat is applied to the rubber sheets S, the same do not deteriorate in quality, so that it can be realized to easily obtain the rubber sheet blanks which are uniform also in quality. 
     In the foregoing embodiments, since the apparatus is constructed to joint the end surfaces S 1  of the two rubber sheets S by allowing the holder portions  31 ,  32 ,  45 ,  46  to overlap with each other through complementary meshing of the rugged portions  31   a ,  32   a ,  45   a ,  46   a  each taking the comb tooth shape, it can be realized to pressure-contact the joint end surfaces S 1  of the rubber sheets S steadily and to improve the jointing accuracy. 
     In the foregoing embodiments, since the wave claws  31   b ,  32   b ,  45   b ,  46   b  are formed on the respective surfaces of the holder portions  31 ,  32 ,  45 ,  46  which contact with the rubber sheets S, to bite the rubber sheets S, it becomes possible to joint the rubber sheets S securely with a strong pressure force. 
     In the foregoing embodiments, since the relative moving amount given by the operating means (i.e., the second cylinder actuators)  47 ,  48  between the first and second holding means  21 ,  22  is set to give the predetermined pressuring allowance (ΔL) between the two rubber sheets S being respectively held by the first and second holding means  21 ,  22 , it becomes possible to heighten the jointing strength of the rubber sheets S nevertheless any bulge hardly occurs at the joint end portions of the rubber sheets S. 
     In the foregoing embodiments, since the holder portions  31 ,  32 ,  45 ,  46  which are able to overlap to mesh with each other are respectively provided on the mutually facing surfaces of the first and second holders  23 ,  24 ,  41 ,  42 , it becomes possible to pressure-contact the joint end surfaces S 1  with each other with the two rubber sheets S being held over the entire parts of the joint end portions thereof, and hence, even when the both rubber sheets S are pressure-joined with a strong pressuring force, any bulge can be prevented from occurring on the joint end portions. In addition, the third holders  55 ,  56  for holding the rubber sheet S delivered to and from the first holders  23 ,  24  are fed by the predetermined amount LA whenever fed, it becomes possible to position a new or next joint end surface S 1  of the jointed rubber sheet S to which another rubber sheet S is to be jointed, to the predetermined position at all times. Therefore, the jointing of the rubber sheets S can be performed efficiently only by holding a newly supplied rubber sheet strip S by the second holders  41 ,  42  and then by moving the second holders  41 ,  42  relative to the first holders  23 ,  24 . 
     In the foregoing embodiments, the first holders  23 ,  24  holding the joint end portion of one of the two rubber sheets S and the second holders  41 ,  42  holding the joint end portion of the other rubber sheet S are relatively moved to the position where they partly overlap with each other, to joint the both rubber sheets S, and the jointed rubber sheet S is fed by the predetermined amount LA relative to the first holders  23 ,  24  to position a new or next joint end surface S 1  of the jointed rubber sheet S to which another rubber sheet S is to be jointed, to the predetermined position at all times. Thus, even when the both rubber sheets S are pressure-joined with a strong pressuring force, any bulge can be prevented from occurring at the joint end portions. This makes it unnecessary to perform a leveling or smoothening step of rolling or leveling any bulge which would otherwise be formed on the rubber sheet S after the jointing step. Accordingly, it can be realized to the jointing method capable of efficiently manufacturing the rubber sheet blanks which are uniform in thickness and excellent in flatness. 
     (Third Embodiment) 
     Hereafter, description will be made regarding a rubber sheet jointing apparatus and method which is practiced for jointing the opposite ends of a rubber sheet  115 , that is, for jointing the first and last or N-th rubber sheet strips of the rubber sheet S manufactured in any of the foregoing first and second embodiments. Although the rubber sheet jointing apparatus and method in the third embodiment according to the present invention is preferably applied to the manufacturing of body plies for automotive tires, the apparatus and method is not limited only to any particular filed of application. 
     Referring now to  FIG. 13 , there is schematically shown a manufacturing apparatus  110  for cylindrical or round rubber sheet blanks such as body or carcass plies for automotive tires. The terms “carcass ply” and “body ply” are interchangeably used in the same meaning herein. The rubber sheet  115  is of a plane form and will be called “plane rubber sheet  115 ” occasionally in the following description. 
     The manufacturing apparatus  110  is composed primarily of a rubber sheet transfer device  111  for transferring a cord-reinforced rubber sheet  115  which is to become a carcass or body ply of a tire, a rubber sheet winding device  112  for winding the rubber sheet  115  on the circumferential surface of a shaping drum  117 , and a rubber sheet jointing device  113  for jointing the circumferential opposite ends of the rubber sheet  115 . 
     As shown in  FIG. 14 , the rubber sheet transfer device  111  is provided with a transfer table  123  movably supported on a pair of rails  122  and a support table  124  vertically movably supported on the transfer table  123 , and the rubber sheet  115  is placed on the support table  124 . In the present embodiment, it is assumed that the rubber sheet  115  is made by cutting an unvulcanized rubber ribbon which has been scrolled around a bobbin (not shown) in advance, to those sheets of a predetermined length determined in dependence on the kind, size and the like of the tires to be manufactured. However, in a modified form, the rubber sheet  115  may be made by joining plural elongated rubber sheet strips one after another at their side surfaces parallel to the lengthwise direction of the rubber sheet strips, as described in the foregoing embodiments. 
     The rubber sheet winding device  112  rotatably supports a shaping drum  117  whose construction will be referred to later in detail. The support table  124  with the rubber sheet  115  placed thereon is transferred together with the transfer table  123 , and when one end (i.e., a winding start end portion)  115   a  is positioned under the axis of the shaping drum  117 , the support table  124  is moved upward by an elevation cylinder actuators  125 . Thus, the winding start end portion  115   a  of the rubber sheet  115  is brought into contact with the circumferential surface of the shaping drum  117 . In this state, the shaping drum  117  is rotated, in synchronous relation with which the rubber sheet transfer device  111  is further moved forward. As a consequence, the rubber sheet  115  is wound as one turn on the circumferential surface of the shaping drum  117 , wherein the winding start end portion  115   a  of the rubber sheet  115  becomes to face a winding terminal end portion  115   b  thereof with a slight clearance therebetween. 
     Next, the structure of the shaping drum  117  will be described with reference to  FIG. 17 . The shaping drum  117  is provided with a shaft sleeve  130  and a pair of discs  131   a ,  131   b  secured to the axial opposite ends of the shaft sleeve  130 . The shaft sleeve  30  is rotatably carried on the rubber sheet winding device  112  and is rotatable by rotation drive means (not shown) through a predetermined angle. 
     A plurality of segments  133  arranged at an equiangular distance circumferentially of the shaft sleeve  130  are carried between the pair of discs  131   a ,  131   b  to be movable in radial directions. Brackets  134   a ,  134   b  are secured at both axial end portions on the internal surface of each segment  133  and are guided and supported on the axially inside surfaces of the respective discs  131   a ,  131   b  to be movable radially. A drum diameter altering member  136  of a generally cylindrical shape is fit on the external surface of the shaft sleeve  130  to be axially movable relative thereto, and slant cam members  137   a ,  137   b  inclined at a predetermined angle with the axis of the drum diameter altering member  136  are formed at both axial end portions of the circumferential surface of the drum diameter altering member  136 . The brackets  134   a ,  134   b  which are attached to the internal surface of each segment  133  are guided along the slant cam members  137   a ,  137   b  through guide members  138   a ,  138   b , respectively. 
     An adjuster shaft  140  is rotatably supported inside the shaft sleeve  130  to pass through the same and is rotatable by rotation drive means (not shown). Inside the shaft sleeve  130 , a ball screw shaft  141  is rotatably supported and is connected to an inner end of the adjuster shaft  140 . The ball screw shaft  141  has screw-engaged therewith a nut  142 , which is connected with the drum diameter altering member  136  through a connection plate  143 . 
     With the construction as aforementioned, when the ball screw shaft  141  is rotated upon rotation of the adjuster shaft  140 , the drum diameter altering member  136  is axially moved through the nut  142  and the connection plate  143 . This causes the respective segments  133  to synchronously move in radial directions intersecting the axis of the shaft sleeve  130 , whereby adjustment is performed to alter the drum diameter of the shaping drum  117  constituted by the gathering of the plural segments  133 . 
     In order to cover or fill the space which would otherwise be made between every two adjoining segments  133  in connection with the alteration adjustment in the drum diameter of the shaping drum  117 , rugged portions  133   a ,  133   b  of a predetermined depth as shown in  FIG. 18  are formed respectively at the both end portions in the circumferential direction of each segment  133 , and the adjoining segments  133  can complementarily overlap with each other through the meshing of the rugged portions  133   a ,  133   b . Thus, the external surface of the shaping drum  117  can be formed to continue in the circumferential direction. 
     Of the foregoing plural segments  133  arranged circumferentially, a pair of jointing segments  145 ,  146  which correspond to seams at the circumferential opposite end portions of the rubber sheet  115  respectively have at their facing end surfaces rugged portions  145   a ,  146   a  of a comb tooth shape formed to a predetermined depth, and these rugged portions  145   a ,  146   a  of the comb tooth shape can complementarily mesh with each other. Thus, the jointing segments  145 ,  146  have formed at their external surfaces holder portions  145   a ,  145   b  which are capable of holding the circumferential opposite end portions of the rubber sheet  115  at convex portions of the comb tooth shape. In this way, by overlapping the pair of jointing segments  145 ,  146  with each other through the complementary meshing between the comb-tooth shape rugged portions  145   a ,  146   a , it becomes possible to joint the circumferential opposite end portions of the rubber sheet  115  with each other with the jointing segments  145 ,  146  holding the entire parts of the both extreme end portions in the circumferential direction of the rubber sheet  115 . 
     As shown in  FIG. 21 , the holder portions  145   a ,  145   b  have formed thereon wave claws  145   c ,  146   c  such as, e.g., saw tooth claws of a minute height which bite the surfaces at the circumferential opposite end portions of the rubber sheet  115  so that the surfaces at the circumferential opposite end portions do not retract relative to the holder portions  145   a ,  145   b  during the jointing operation. 
     Each of the pair of jointing segments  145 ,  146  protrudes engaging pins  147 ,  148  from the axial opposite end portions thereof. The distance (L 2 ) in a tangential direction of the shaping drum  117  (e.g., in the circumferential direction) between the engaging pins  147 ,  148  are varied by the movements of the segments  145 ,  146  in the radial directions, that is, by the increase or decrease of the drum diameter of the shaping drum  117 . Thus, when the drum diameter is decreased, the circumferential opposite end portions of the rubber sheet  15  which portions are being held by the jointing segments  145 ,  146  are brought into contact with each other. 
     Next, with reference to  FIGS. 15 ,  16  and  19 , description will be made regarding the construction of the rubber sheet jointing device  113  for jointing the circumferential opposite end portions of the rubber sheet  115  being wound around the shaping drum  117 . The rubber sheet jointing device  113  is arranged over the shaping drum  117 , and a fixed frame  150  thereof guides a vertically movable member  152  through a plurality of guide bars  151  in a vertical direction (in a radial direction of the shaping drum  117 ). The vertically movable member  152  is movable by a pressuring cylinder actuator  153  mounted on the fixed frame  150  toward and away from the shaping drum  117 . A pair of guide rails  155  respectively constituting linear guides are mounted on an end (lower end) of the vertically movable member  152  to extend tangentially of the shaping drum  117 , and two horizontally movable members  157 ,  158  are mounted on the guide rails  155  through guide blocks  159 ,  160  to come close to or away from each other in a tangential direction (the circumferential direction) of the shaping drum  117 . 
     That is, the two horizontally movable members  157 ,  158  are arranged to face with each other with the vertical axis (L 0 ) (refer to  FIG. 21 ) therebetween and have the length corresponding approximately to the length of the shaping drum  117  in the axial direction of the same. As best shown in  FIG. 19 , rugged portions  157   a ,  158   a  each taking a comb tooth shape are formed on the mutually facing end surfaces of the respective horizontally movable members  157 ,  158  to a predetermined depth and are able to complementarily mesh with each other. Thus, pressuring portions  157   b ,  158   b  are formed on the lower surfaces of the horizontally movable members  157 ,  158  for pressuring the circumferential opposite end portions of the rubber sheet  115  by the rugged portions  157   a ,  158   a  of the comb tooth shape over the entire lengths thereof. In this way, by partly overlapping the pair of horizontally movable members  157 ,  158  through the complementary meshing between the rugged portions  157   a ,  158   a  of the comb tooth shape, it becomes possible to joint the circumferential opposite end surfaces of the rubber sheet  115  with the pressuring portions  157   b ,  158   b  of the horizontally movable members  157 ,  158  pressuring the circumferential opposite end edge portions of the rubber sheet  115  downward. 
     As shown in  FIG. 21  in detail, the pressuring portions  157   b ,  158   b  have formed thereon wave claws  157   c ,  158   c  such as, e.g., saw tooth claws of a minute height which bite the external surfaces at the circumferential opposite end portions of the rubber sheet  115  so that the circumferential opposite end portions do not retract relative to the pressuring portions  157   b ,  158   b  to separate from each other during the jointing operation. 
     As shown in  FIGS. 19 and 20 , the horizontally movable members  157 ,  158  respectively protrude contact pieces  161 ,  162  toward the vertically movable member  152  and are each urged by the resilient force of a compression spring  164  arranged between itself and a bracket  163  secured to the vertically movable member  152 , to come into contact with a stop  165  or  166  associated therewith. Usually, the horizontally movable members  157 ,  158  are held at respective positions where the contract pieces  161 ,  162  are kept in abutment with the stops  165 ,  166 , respectively. Thus, the movable members  157 ,  158  are prevented from relatively moving in a direction to go away from each other beyond the stops  165 ,  166 , but are allowed to relatively move in the other direction to come close to each other (in the direction against the resilient force of the compression springs  163 ). 
     Engaging blocks  167 ,  168  are attached to the opposite ends in the lengthwise direction of the horizontally movable members  157 ,  158  and have formed thereon engaging grooves  167   a ,  168   a  (refer to  FIG. 21 ) opening downward, respectively. The engaging grooves  167   a ,  168   a  of the engaging blocks  167 ,  168  are brought by the downward advance movement of the vertically movable member  152  into engagement with the engaging pins  147 ,  148  protruding from the pair of jointing segments  145 ,  146 , respectively. The respective horizontally movable members  157 ,  158  are synchronously moved to come close to each other when the contraction in the drum diameter of the shaping drum  117  causes the pair of jointing segments  145 ,  146  to advanced toward each other in the tangential direction of the shaping drum  117  with the engaging grooves  167   a ,  168   a  being engaged with the engaging pins  147 ,  148 , respectively. 
     The foregoing engaging blocks  167 ,  168  and the engaging pins  147 ,  148  constitute synchronous moving means recited in the claimed invention, and the synchronous moving means is able to move the holder portions  145   a ,  145   b  formed in the jointing segments  145 ,  146  and the pressuring portions  157   b ,  158   b  formed on the horizontally movable members  157 ,  158  in a synchronous relation with each other. The construction of the synchronous moving means is not limited to that described above. For example, the engaging pins  147 ,  148  may be provided on the sides of the horizontally movable members  157 ,  158 , whereas the engaging blocks  167 ,  168  may be provided on the sides of the jointing segments  145 ,  146 . 
     (Operation) 
     The operation of the third embodiment as constructed above will be described hereinafter. First of all, description will be made regarding the operation for winding the rubber sheet  115  on the circumferential surface of the shaping drum  117 . It is now assumed that prior to the winding operation of the rubber sheet  115 , the shaping drum  117  is kept in an expansion state with the pair of the jointing segments  145 ,  146  being positioned to an angular position where they are placed beneath the axis of the shaping drum  117 . 
     When a rubber sheet  115  having been cut to the predetermined length determined in dependence on the kind, dimension and the like of the tires to be manufactured is placed on the support table  124  of the rubber sheet transfer device  111 , the transfer table  123  supporting the support table  124  thereon is transferred by the transfer cylinder actuator (not shown) along the rails  122  toward the right as viewed in  FIG. 13 , and one end (the winding start end portion)  115   a  of the rubber sheet  115  is positioned to a position which corresponds to one of the jointing segments  145 ,  146  positioned beneath the shaping drum  117 . 
     Thereafter, the support table  124  of the rubber sheet transfer device  111  is moved upward by the elevation cylinder actuators  125 , and the winding start end portion  115   a  of the rubber sheet  115  is brought into contact with the circumferential surface (with one of the pair of jointing segments  145 ,  146 ) of the shaping drum  117  and is made by cling holding means (not shown) to cling to the circumferential surface of the shaping drum  117 . In this state, the transfer table  123  supporting the support table  124  thereon is further transferred toward the right as viewed in  FIG. 13 , simultaneously with which the shaping drum  117  is rotated by the rubber sheet winding device  112 . This causes the rubber sheet  115  to be wound as approximately one turn around the circumferential surface of the shaping drum  117 , whereby in the same manner as is done with the winding start end portion  115   a , the winding terminal end portion  115   b  of the rubber sheet  115  is made by the cling holding means (not shown) to cling to the circumferential surface (to the other of the pair of jointing segments  145 ,  146 ) of the shaping drum  117 . 
     In this way, the seams being respectively the winding start end portion  115   a  and the winding terminal end portion  115   b  of the rubber sheet  115  are placed on the circumferential surface of the shaping drum  117 , that is, between the jointing segments  145 ,  146  to face each other with a slight clearance therebetween in the circumferential or tangential direction of the shaping drum  117 . Then, the shaping drum  117  is rotated by the rubber sheet winding device  112  through about  180  degrees to position the seams of the rubber sheet  115  to an upward angular position where the seams face the rubber sheet jointing device  113 . 
     In this state, the vertically movable member  152  of the rubber sheet jointing device  113  is moved down by the pressuring cylinder actuator  153 , whereby the engaging grooves  167   a ,  168   a  of the engaging blocks  167 ,  168  attached to the horizontally movable members  157 ,  158  are brought into engagements respectively with the engaging pins  147 ,  148  and whereby the pressuring portions  157   b ,  158   b  of the horizontally movable members  157 ,  158  are pressured by the thrust force of the pressuring cylinder actuator  153  respectively upon the circumferential opposite end portions of the rubber sheet  115 . Thus, the circumferential opposite end portions of the rubber sheet  115  are pinched from radial inside and outside by the holding portions  145   b ,  146   b  of the jointing segments  145 ,  146  and the pressuring portions  157   b ,  158   b  of the horizontally movable members  157 ,  158 . The pinching of the rubber sheet  115  by the jointing segments  145 ,  146  and the horizontally movable members  157 ,  158  is kept by a later follow motion of the pressuring cylinder actuator  153  while the drum diameter of the shaping drum  117  is decreased. 
     Subsequently, the adjuster shaft  140  of the shaping drum  117  is rotated by the rotation drive means (not shown). Upon rotation of the adjuster shaft  40 , the ball screw shaft  141  is rotated to axially move the drum diameter altering member  136  toward the right as viewed in  FIG. 17  through the nut  142  and the connection plate  143 . Thus, by the cam action of the cam members  137   a ,  137   b , the plurality of circumferentially arranged segments  133  including the jointing segments  145 ,  146  are moved radially inward along the guide members  135   a ,  135   b  to decrease the drum diameter of the shaping drum  117 . 
     With the decrease in the drum diameter of the shaping drum  117 , the pair of jointing segments  145 ,  146  which correspond to the seams at the circumferential end portions of the rubber sheet  115  are moved inward in the radial direction as they are moved in the tangential direction (in the circumferential direction) of the shaping drum  117  perpendicular thereto. This causes the engaging pins  147 ,  148  protruding from the pair of jointing segments  145 ,  146  to decrease the distance (L 2 ) (refer to  FIG. 21 ) in the tangential direction with the decrease in the drum diameter of the shaping drum  117 . Thus, the pair of horizontally movable members  157 ,  158  which engage the engaging pins  147 ,  148  through the engaging blocks  167 ,  168  are also relatively moved to come close to each other synchronously with the movements in the tangential direction (the circumferential direction) of the jointing segments  145 ,  146 . 
     Since in this way, the holder portions  145   b ,  146   b  of the jointing segments  145 ,  146  and the pressuring portions  157   b ,  158   b  of the horizontally movable members  157 ,  158  which cooperate to pinch the circumferential opposite end portions of the rubber sheet  115  are moved to come close to each other with the decrease in the drum diameter of the shaping drum  117 , the circumferential opposite end portions (the winding start end portion  115   a  and the winding terminal end portion  115   b ) of the rubber sheet  115  are caused to come close to each other and finally, are strongly pressured on each other at their end surfaces to be butt-jointed. 
     At this time, since the jointing segments  145 ,  146  having the holder portions  145   b ,  146   b  formed thereon and the horizontally movable members  157 ,  158  having the pressuring portions  157   b ,  158   b  formed thereon which cooperate to pinch the rubber sheet  115  are overlapped at their rugged portions  145   a ,  146   a ,  157   a ,  158   a  of the comb tooth shape, the circumferential opposite end surfaces of the rubber sheet  115  can be pressure-jointed through the predetermined pressuring allowance while the circumferential opposite end portions of the rubber sheet  115  are fully pinched over the entire parts thereof. The wave claws  145   c    146   c ,  157   c ,  158   c  formed on the holder portions  145   b ,  146   b  and the pressuring portions  157   b ,  158   b  prevent the rubber sheet  115  from slipping during the jointing operation. 
     As a consequence, even when the circumferential opposite end portions of the rubber sheet  115  are pressure-jointed with a strong pressuring force, the pressure-jointed portion does not have any bulge thereon and can be improved in flatness. Further, since any bulge does not occur, it becomes unnecessary to roll or level any bulged portion which would otherwise occur, with the rubber sheet  115  being heated as is done in the prior art, and therefore, the rubber sheet  115  can be kept uniform in quality without being degenerated by the heat. 
     Upon completion of the step of jointing the circumferential opposite end portions of the rubber sheet  115  in this manner, the circumferential surface of the rubber sheet  115  now taking a round form is held by a vacuum pad (not shown) as described in, e.g., Japanese Published, Unexamined Patent Application No. 2001-138404, in which state the vacuum pad is then moved axially of the shaping drum  117  to remove the round rubber sheet  115  from the circumferential surface of the shaping drum  117 . Thereafter, the round rubber sheet  115  removed from the circumferential surface of the shaping drum  117  is transferred to a tire assembling station (not shown) next to the manufacturing apparatus  110 . 
     In the foregoing third embodiment, by the contraction in the drum diameter of the shaping drum  117 , the pair of jointing segments  145 ,  146  with the holder portions  145   b ,  146   b  formed thereon are moved radially of the shaping drum  117  as they are moved in the tangential direction of the shaping drum  117 , and the circumferential opposite end portions of the rubber sheet  115  are pressure-jointed by the utilization of the relative movement of the holder portions  145   b ,  146   b  in the tangential direction. However, where it is desired that the relative movement between the holder portions  145   b ,  146   b  in the tangential direction of the shaping drum  117  be much longer, there may be employed individual relative moving means which are provided for effecting the relative movement between the holder portions  145   b ,  146   b  independently of the jointing segments  145 ,  146 . 
     As described above, in the aforementioned third embodiment, the meshing portions which are able overlap to mesh with each other are formed on the holder portions  145   b ,  146   b  which are movable radially of the shaping drum  117 , as well as on the pressuring portions  157   b ,  158   b  which are provided on the vertically movable member  152  to be relatively movable in the tangential direction of the shaping drum  117  for pressuring the circumferential opposite end portions of the rubber sheet  115  respectively on the holder portions  145   b ,  146   b . Further, the synchronous moving means  167 ,  168 ,  147 ,  148  is provided for relatively moving the holder portions  145   b ,  146   b  and the pressuring portions  157   b ,  158   b  in the synchronous relation in the tangential direction of the shaping drum  117 . Thus, relative movements in the synchronous relation are performed between the holder portions  145   b ,  146   b  as well as between the pressuring portions  157   b ,  158   b  with all the parts of the circumferential opposite end portions of the rubber sheet  115  being pinched by the holder portions  145   b ,  146   b  and the pressuring portions  157   b ,  158   b . Accordingly, it can be realized to obtain the rubber sheet jointing apparatus which is capable of jointing the circumferential opposite end portions of the rubber sheet  115  easily and reliably without having any bulge at the jointed portion. 
     Also in the aforementioned third embodiment, since each of the holder portions  145   b ,  146   b  and the pressuring portions  157   b ,  158   b  has the wave claws  145   c ,  146   c ,  157   c ,  158   c  which are formed at the contact surface with the rubber sheet  115  for biting the rubber sheet  115 , it is possible to securely joint the circumferential opposite end portions with a strong pressuring force. 
     Also in the aforementioned third embodiment, the synchronous moving means is composed of the engaging pins  147 ,  148  respectively provided on the holder portions  145   b ,  146   b  and the engaging members  167 ,  168  respectively provided on the pressuring portions  157   b ,  158   b  and engageable by the advance movement of the vertically movable member  152  respectively with the engaging pins  147 ,  148 . Thus, by the advance or retraction movement of the vertically movable member  152 , the engaging members  167 ,  168  are brought into engagements with the engaging pins  147 ,  148 , so that the synchronous moving means can be simplified in construction. 
     Further, in the aforementioned third embodiment, the circumferential opposite end portions of the rubber sheet  115  are pinched between the holder portions  145   b ,  146   b  which are provided on the shaping drum  117  to mesh with each other in the partly overlapping state and the pressuring portions  157   b ,  158   b  which are provided on the vertically movable member  152  to mesh with each other in the partly overlapping state, and with the circumferential opposite end portions being pinched, the relative movement in the tangential direction of the shaping drum  117  is performed between the holder portions  145   b ,  146   b  as well as between the pressuring portions  157   b ,  158   b , whereby the circumferential opposite end portions of the rubber sheet  115  are butt-jointed with each other. Thus, it can be realized to pressure-joint the circumferential opposite end portions of the rubber sheet  115  with each other with the circumferential opposite end portions being fully held over the entire parts thereof. Therefore, even when the circumferential opposite end portions are jointed with a strong pressuring force, the jointed portion can be prevented from having any bulge thereat. Since this advantageously makes unnecessary any smoothening step which would otherwise be required for rolling or leveling any such bulge after the jointing of the rubber sheet  115 , it becomes possible to easily obtain the rubber sheet jointing method capable of efficiently manufacturing the rubber sheet  115  which is uniform in thickness, excellent in flatness and also uniform in quality. 
     The specific constructions of the rubber sheet jointing device  113  and the shaping drum  117  described in the foregoing third embodiment are only to show an example suitable to implementing the present invention. Of course, the present invention is not limited to the constructions as described above and may take any of various forms without departing from the gist of the present invention. 
     (Fourth Embodiment) 
       FIGS. 22 through 26  show the fourth embodiment according to the present invention, which is designed to manufacture an endless band by butt-jointing a forward end portion of the rubber sheet batch S, which is manufactured as described in the foregoing first embodiment to have the predetermined length corresponding to one tire, with a rear end portion of the rubber sheet batch S. 
     The fourth embodiment is further provided with a rubber sheet batch turning-up means  81  for turning up the rubber sheet batch S to a position which enables the second holding means  22  to hold the forward end portion of the rubber sheet batch S in such a way that the rubber sheet batch turning-up means  81  grips the forward end of the rubber sheet batch S which is sent out by the predetermine amount from between the third holders  55 ,  56  of the feeding means  54  and then moves the forward end portion of the rubber sheet batch S step by step along a loop locus. The fourth embodiment differs from the foregoing first embodiment in the respect that it is provided with the rubber sheet batch turning-up means  81 . The fourth embodiment and the foregoing first embodiment take the same construction and perform the same operation in manufacturing the rubber sheet batch S of the predetermined length corresponding to one tire. Therefore, also with reference to some figures for the first embodiment, the following description will be addressed mainly to the differences from the first embodiment. In  FIGS. 22 and 23 , components identical to those in the first embodiment are given the same reference numerals as used in the first embodiment, and the description of the identical components will be omitted for the sake of brevity. 
     In the fourth embodiment wherein the endless band is manufactured, it is necessary to take the manufactured band away from the rubber sheet jointing apparatus  10  described in the foregoing first embodiment. Therefore, in the fourth embodiment, one of the pair of support pillars  13 ,  14  (i.e., the support pillar  13 ) upstanding in the rubber sheet jointing apparatus  10  as shown in  FIG. 3  is removed, and the rubber sheet jointing apparatus  10  is supported by the other support pillar  14  only in a cantilever fashion (refer to  FIG. 22 ), in which respect the fourth embodiment is also different from the first embodiment. 
     Hereafter, the fourth embodiment will be described with reference to  FIGS. 22 through 26  taking an example wherein a material handling robot is utilized as the rubber sheet batch turning-up means  81 . The robot has a robot arm  83 , which is provided with a pair of hands  85  and  86  operable to open and close, as shown in  FIG. 25 . These hands  85 ,  86  are operable to grip the forward end portion of the rubber sheet batch S which is sent out from the pair of third holders  55 ,  56 . At this time, as shown in  FIG. 24 , the hands  85 ,  86  grip a portion of the rubber sheet batch S retracted from the end face S 11  of the forward end portion for handover or delivery between themselves and the second holders  41 ,  42 . 
     The robot arm  83  has the freedom of at least three axes in movement, wherein it is movable in the left-right direction (Y-axis direction) and the vertical direction (Z-axis direction) as viewed in  FIG. 23  and is rotatable about a  9 -axis perpendicular to the Y and Z-axes. Thus, with simultaneous controls of the robot arm  83  along the three axes, the forward end portion of the rubber sheet batch S gripped by the hands  85 ,  86  is turned up to a position to face the rear end portion of the rubber sheet batch S while being controllably moved along the loop locus LL shown in  FIG. 26  step by step, each step corresponding to the width dimension LA of the rubber sheet strip shown in  FIG. 10 . 
     Further, in the fourth embodiment, as described in the foregoing first embodiment, the rubber sheet strips S are successively supplied by the supply means  70  to the butt joint station  2   st  and are jointed one after another to manufacture the rubber sheet batch S. When the forward end portion of the rubber sheet batch S (i.e., the first rubber sheet strip) is protruded by a predetermined amount from the third holders  55 ,  56 , the hands  85 ,  86  of the robot arm  83  grip the forward end portion of the rubber sheet batch S, as shown in  FIGS. 22 and 24 . With the gripping state being kept, the robot arm  83  under the simultaneous controls of the three axes is controllably moved along the loop locus LL shown in  FIG. 26  by the step or distance corresponding to the width dimension LA of each rubber sheet strip in turn in the direction of the arrow indicated in  FIG. 26  each time the rubber sheet batch S is sent out by the predetermined distance upon completion of the jointing of each rubber sheet strip. 
     When the rubber sheet batch S of the predetermined length corresponding to one tire is manufactured in this way, the robot arm  83  reaches the position shown in  FIG. 26 , whereby the forward end portion of the rubber sheet batch S gripped by the hands  85 ,  86  of the robot arm  83  is positioned to a position where it can be held by the second holding means  22 . That is, as shown in  FIG. 4 , the end surface  511  of the forward end portion of the rubber sheet batch S comes to take the position which is between the second holders  41  and  42  and which is retracted by the slight amount L 1  from the end surfaces of the rugged portions  45   a ,  46   a  of the comb tooth shape. 
     In this state, in the same manner as described in the first embodiment, each pair of the first holders  23 ,  24  and the second holders  41 ,  42  are vertically moved by the operations of the first cylinder actuators  29 ,  30  to come close to each other, whereby the rear end portion of the rubber sheet batch S being held by the third holders  55 ,  56  is held by the first holders  23 ,  24  while the forward end portion of the rubber sheet batch S being held by the hands  85 ,  86  of the robot arm  83  is held by the second holders  41 ,  42 . Therefore, as indicated by the two-dot-chain line in  FIG. 4 , the rubber sheet batch S has its rear end surface held by the holder portions  31 ,  32  at the position retracted by the distance L 1  from the end surfaces of the rugged portions  31  a,  32   a  of the comb tooth shape and also has its forward end surface held by the holder portions  45 ,  46  at the position retracted by the distance L 1  from the end surfaces of the rugged portions  45   a ,  46   a  of the comb tooth shape. 
     Then, the second holders  41 ,  42  are moved by the operations of the second cylinder actuators  47 ,  48  toward the first holders  23 ,  24 , and the end surface S 11  of the forward end portion of the rubber sheet batch S (i.e., the first rubber sheet strip) being held by the second holders  41 ,  42  is pressured on the end surface S 12  of the rear end portion of the rubber sheet batch S (i.e., the last jointed rubber sheet strip) being held by the first holders  23 ,  24  as the comb tooth shape rugged portions  45   a ,  46   a  formed on the second holders  41 ,  42  are complementarily meshed with the comb tooth shape rugged portions  31   a ,  32   a  formed on the first holders  23 ,  24 , whereby the endless band is manufactured with the first rubber sheet strip and the last jointed rubber sheet strip being jointed with each other. 
     The endless band manufactured in this way is taken out by a band taking-out means (not shown) in the X-axis direction (the left-right direction as viewed in FIG.  22 ) to be carried out of the rubber sheet jointing apparatus  10  and is transferred to a tire assembling step or apparatus (not shown). 
     According to the foregoing fourth embodiment, by the use of the rubber sheet jointing apparatus  10  similar to that described in the first embodiment, it can be realized to manufacture the rubber sheet batch S of the predetermined length from the plurality of rubber sheet strips S and to continuously manufacture the endless band from the rubber sheet batch S. Accordingly, it can be realized to manufacture the endless bands suitable for use in tires efficiently by the use of the space-saving equipment or facilities. 
     In particular, where the fourth embodiment is practiced, it becomes unnecessary to provide the rubber sheet jointing apparatus  110  as used in the third embodiment for jointing the opposite ends of the rubber sheet  115  (i.e., the rubber sheet batch S in the fourth embodiment). Therefore, a tire production system including the rubber sheet jointing apparatus  10 , the tire assembling apparatus and the like can be simplified in construction and reduced in scale, so that substantial achievements can be realized not only in reducing the cost for manufacturing the tire production system, but also in enhancing the tire productivity as a result of the cycle time for tire production being shortened. 
     Although the fourth embodiment has been described taking the example wherein the robot is utilized in turning up the forward end portion of the rubber sheet batch S to the position to face the rear end portion of the rubber sheet batch S, the present invention is not necessarily limited to utilizing the robot. For example, the fourth embodiment may be modified to take a construction wherein gripper means for gripping the forward end portion of the rubber sheet batch S is provided on a movable member which is movably guided along a loop guide member and wherein the movable member is moved along the guide member to controllably move the forward end portion of the rubber sheet batch S along the loop locus. 
     Although the fourth embodiment has been described taking the example wherein tire body plies are manufactured, it may be applied to the manufacturing of the belts of automotive tires with steel cords embedded therein as practiced in the foregoing second embodiment. 
     Obviously, numerous further modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.