Abstract: A continuous elongated element of elastomeric material is produced through an extruder at a linear delivery speed and directly fed onto a moving surface of a conveyor without interposition of other devices. The continuous elongated element is advanced on the moving surface along a predetermined direction and at a linear advancing speed different from the linear delivery speed until a proximal end of the conveyor. Subsequently, the continuous elongated element is applied onto a forming support which rotates relative to the proximal end of the conveyor at a peripheral speed different from the linear delivery speed, so as to deform the continuous elongated element and apply it in the form of wound coils onto the forming support in order to form a component of elastomeric material of a tyre.

Abstract: Even when a radial length of a swing arm is increased, no gap is generated between adjacent segments, and tires of various sizes can be handled while roundness of a drum is maintained. An expandable molding drum has a plurality of segments constituting a circumferential surface, the molding drum having a plurality of swing arms having one end portion swingably connected to an outer circumferential surface of a cylindrical slider externally fitted with a drum shaft and having the other end portion swingably connected to the segment and expanding/contracting the segment along with movement of the slider in a drum shaft direction, and adjacent end portions of one end portions of the swing arms being swingably connected to the outer circumferential surface of the slider at intervals from each other in the drum shaft direction.

Abstract: A tire having a modified geodesic belt is described. The ideal geodesic belt path is modified to select the centerline belt angle and to avoid excessive build up of the belt at the belt edges. The method includes the step of calculating the minimum three dimensional distance from one belt edge to the other belt edge preferably using dynamic successive approximation.

Abstract: A strip rubber adhering method includes: extruding strip rubber of a shape having an apex portion in cross section from an extruder and moving the same forward toward a drum; pressing a surface of the strip rubber on the apex portion side by a pressure bonding roller, adhering the strip rubber to the drum, moving relatively the drum and the extruder with respect to each other in an axial direction of the drum, and winding the strip rubber around the drum in a spiral manner; and exposing the surface of the strip rubber on the apex portion side to wind from a blowing apparatus in the vicinity of a position of adhesion of the strip rubber to the drum and cooling the surface of the strip rubber on the apex portion side.

Abstract: Methods and apparatus for forming a multi-layered tire component, the steps of the method including providing a mechanical system, the system including a plurality of cutting members; translating a sheet of material along a translation path through the mechanical system; cutting a first strip from the sheet with one or more of the plurality of cutting members, this step occurring during the step of translating; mechanically applying the first strip to a building surface, this step occurring during the step of translating; cutting a second strip from the sheet subsequent to the step of cutting the first strip, this step occurring during the step of translating; mechanically applying the second strip to a building surface, this step occurring during the step of translating.

Abstract: A pneumatic tire molding device includes an extruder which mixes and discharges a rubber material, a mouth piece which is attached to a leading end of the extruder, and a rotary support body around which a rubber strip discharged out of a discharge port of the mouth piece is wound, wherein a receiving portion is formed in the mouth piece closer to a rear side in a rotating direction of the rotary support body than the discharge port in an end surface facing to a rotation surface of the rotary support body, the receiving portion being capable of receiving the rubber strip which has been already wound around the rotary support body.

Abstract: A method and a plant for manufacturing tires for vehicle wheels wherein the method includes the steps of: a) building in a building station a substantially cylindrical carcass structure; b) manufacturing in a finishing station a substantially cylindrical sleeve including a tread band applied at a radially outer position with respect to a belt structure including at least one belt layer. Step b) includes the steps of assembling a first belt structure at a first working position on a first auxiliary drum of the finishing station; applying a tread band at a second working position at a radially outer position with respect to a second belt structure previously assembled on a second auxiliary drum of the finishing station, positioning the first auxiliary drum supporting the first belt structure at the second working position; and positioning the second auxiliary drum supporting the substantially cylindrical sleeve thus obtained at a picking position of the finishing station.

Abstract: Building the carcass structure of tyres for vehicle wheels includes associating, at each end edge of a carcass ply, at least one respective annular reinforcement structure formed by depositing along a circumferential direction a plurality of reinforcement elements having a first length. Such elements are cut to size from a reinforced continuous band-like element fed to a cutting group arranged at a first operative position adapted to allow a barycentric grip of the reinforcement elements. The cutting group can translate along a feeding direction of the band-like element to a second operative position for cutting to size a plurality of second reinforcement elements having a second length different from the first length. The second operative position is defined on the basis of the second length, so as to have a barycentric grip of the second reinforcement elements too.

Abstract: A process for manufacturing an elastomeric tire component includes the steps of a) preparing an elongated element including a cross-linkable elastomeric material by feeding it to an extruding device having a plurality of units, each having a respective thermal inertia, and b) delivering the elongated element onto a building support, and further includes at least one non-productive step of c) submitting at least one of the units of the extruding device to a thermal transition selected from heating or cooling, substantially reducing the risk of scorching during the thermal transition from and to the non-productive step ranking the units according to their thermal inertia and heating the units starting with the top-ranked unit sequentially to the bottom-ranked unit to reach the respective working temperature or cooling the units starting from the maximum working temperature unit sequentially to the minimum working temperature unit to reach the respective non-working temperature.

Abstract: In the field of tire building, underbelt inserts are applied to an expandable support associated with an auxiliary drum on which the belt structure is made, simultaneously with manufacture of a carcass structure on a primary drum. Following expansion of the expandable support, the underbelt inserts are applied to the belt structure that can be directly made on the support itself in an expanded condition. The belt structure together with the underbelt inserts and a tread band are then transferred onto the carcass structure formed on the primary drum to complete building of the tire following shaping of the carcass into a toroidal conformation.

Abstract: Production of carcass structures and/or production of crown structures includes: positioning a first continuous elongated element so that its end stretch is aligned with a cutting position; positioning a second continuous elongated element so that its end stretch is in side by side relationship with the end stretch of the first continuous elongated element; forming first strip-like elements from the first continuous elongated element; depositing the first strip-like elements on at least one forming drum; translating the end stretches of the first and second continuous elongated element in a transverse direction relative to their longitudinal extension to align the end stretch of the second continuous elongated element to said cutting position; forming second strip-like elements from the second continuous elongated element; and depositing the second strip-like elements on said at least one forming drum.

Abstract: An applicator assembly for applying a cord to a tire-building surface that rotates during tire construction. The applicator assembly includes an applicator member to apply the cord. A first rotary device rotates the applicator member about a first axis that is transverse to the surface. A first translation device moves the applicator member in a first linear path relative to the surface. The applicator member may include a roller and/or a resilient member. A second rotary device may rotate the applicator member and the first rotary device around a second axis substantially perpendicular to the first axis. A second translation device may move the applicator member, the first rotary device, the second rotary device, and the first translation device. A system for applying the cord to a core member may further include a spindle to rotate the core member about the axis of rotation.

Abstract: The invention provides an assembly and a method for manufacturing a green tyre. The assembly comprises a building drum (52), an extrusion device (75) for extruding a strip (70) of an unvulcanized rubber, a transfer drum (72) for helically winding the strip (70) of the unvulcanized rubber thereon into a layer of rubber material, and a cutting device (76) for at least substantially in axial direction severing the layer of rubber material, wherein the transfer drum (72) is movable between a first position near the extrusion device (52) and a second position near the building drum (52) for transferring the layer of rubber material from the transfer drum (72) to the building drum (52).

Abstract: The tool which contains: a support, and an arm bearing a strip extrusion member and a strip applicator roller, wherein the arm is articulated with respect to the support about a first axis parallel to a geometric axis of the roller and about a second axis tangential to a circumference of the roller, of the first and second axes at least one passing through a centre of gravity of the arm.

Abstract: A device for manufacturing a reinforcing ply N by assembling lengths of strip cut at an angle, comprising: a feed means (300) for delivering a strip (B), an assembly belt (101), a transfer means (200) for conveying onto the assembly belt a given length of straight-grain strip in a direction (AA?) comprising a retaining wall (211), parallel to the planes of the assembly belt (101) and of the feed means, and a first face (211a) of which is intended to come into contact with the surface of the strip, in which device the feed means (300), the transfer means (200) and the assembly belt (101) are fitted with magnetic means.

Abstract: On a building drum, anchoring structures to beads, carcass plies, a belt structure and/or other annular composite components are sequentially assembled with a liner, sidewalls, sidewall inserts, under-belt inserts or other annular elastomer components. Each of the sidewall inserts, sidewalls, or under-belt inserts is made as a one piece construction in a service station operating far away from the building drum for storage on a movable storing device. Actuating members operating on the movable storing device carry the annular elastomer components from the service station to the building drum. A transfer member picks up the annular elastomer components from the movable storing device to transfer them to the building drum.

Abstract: The present application is directed to a method for applying a flexible annular strip to a radially inward oriented surface of a tire. Moreover, the present invention is directed to a corresponding apparatus for carrying out the above method.

Abstract: A process and apparatus for manufacturing tires for vehicle wheels, includes building, on a toroidal support, a carcass structure including at least one carcass ply associated, at axially opposite end edges thereof, with annular anchoring structures, the building step of the carcass structure includes forming at least one reinforcing structure, operatively associated with the annular anchoring structures through deposition on the toroidal support of at least one reinforcing element along a predetermined curvilinear deposition path. The deposition of the at least one reinforcing element includes the steps of: cutting to size a piece of at least one reinforcing continuous band-like element fed by a feeding device along a predetermined feeding direction, deforming the piece obtained according to the curvature of a deposition part of the deposition path intended to receive the piece, and depositing the deformed piece at the deposition part.

Abstract: Device for applying a strip (B) of a viscoelastic material to a receiving surface (S) in relative motion (R) relative to said device, comprising a feed means and an application nozzle (1) having a body (11), into which said feed means (2) emerges, and a head (12) at the end of which there is an outlet orifice (122) of elongate shape in the transverse direction to the direction of the relative motion when the device is operating. The head (12) of the application nozzle (1) is linked to the body (11) of the application nozzle (1) via an articulation (10) which can be deformed along an axis (AA?) perpendicular to the direction of application of the strip (B).

Abstract: During tyre building, a crown structure is built through the actions of: forming at least one belt layer on an auxiliary drum for manufacturing a belt structure at least partly; turning up axially opposite side flaps of said at least one belt layer formed on the auxiliary drum; transferring the belt structure from the auxiliary drum to at least one service drum; and forming a tread band by winding of at least one continuous elongated element of elastomeric material into coils disposed mutually adjacent around the belt structure carried by the service drum.

Abstract: Building a carcass structure of a tyre for vehicle wheels includes associating, at each end edge of a carcass ply laying on a forming support, at least one respective annular reinforcing structure obtained by depositing at least one respective reinforcing element. The deposition process includes feeding a continuous reinforced band-like element at a cutting unit, cutting to size at least one first reinforcing element from the continuous reinforced band-like element, moving the first reinforcing element from the cutting unit toward a first end edge of the carcass ply, positioning the first reinforcing element on the first end edge, cutting to size at least one second reinforcing element from the continuous reinforced band-like element, moving the second reinforcing element from the cutting unit toward a second end edge of the carcass ply opposite said first end edge, and positioning the second reinforcing element on the other end edge.

Abstract: A tooling head for construction of a tire cord to an annular surface is provided having a first roller and a second roller for alternative engagement against the annular surface in a forward and a rearward direction, respectively, the first and second rollers having a spaced apart orientation and annular grooves defining a passageway between the rollers. A guide tube extends between the roller annular grooves within the passageway. A cord exiting guide tube end is axially offset to remote extremities of the first and second roller annular grooves and a first and second axially extending slits are formed within the guide tube opposite the roller annular grooves, respectively.

Abstract: A tire building device includes a building drum for applying an inner liner thereon and a winding device for tire cords wherein the building drum is mounted to a drive shaft only on one of its sides, the drive shaft side. The winding device winds the tire cords onto the inner liner in the final shape also on completion of the tire. The winding device, substantially radially, winds the tire cords on the free side opposite the drive shaft transversely across the building drum and past the drive shaft on the drive shaft side.

Abstract: A process for manufacturing a reinforcing structure of a tyre for vehicle wheels, is carried out on a toroidal support including an outer surface, by means of at least one laying element, which can be oriented in space in a controlled way; the laying element including a laying surface adapted to act on a portion of a rubberized strip-like element for laying the same on the outer surface of the toroidal support. The reinforcing structure includes at least a first and a second radially superimposed reinforcing layers, each including a plurality of strip-like elements; each reinforcing layer having a circumferential extension about a rotation axis of the tyre and comprising thread-like reinforcing elements, arranged parallel to one another.

Abstract: During building of tyres, at least one first forming drum is employed which has a deposition surface and includes sectors radially movable relative to a geometric rotation axis, and circumferentially distributed one after the other. A plurality of strip-like elements is deposited in circumferential side by side relationship on the deposition surface set in the first deposition configuration, to form at least one component of at least one first crown structure. Setting of the deposition surface includes the actions of radially moving the sectors to give the deposition surface a predetermined diameter and carry out a relative movement between a central portion and axially external end portions of each sector to shape the deposition surface according to a predetermined curvature outline.

Abstract: A rubber sheet jointing apparatus is provided with first holding means for releasably holding a joint end portion of one of two rubber sheets, second holding means provided movably relative to the first holding means for releasably holding a joint end portion of the other of the two rubber sheets, and operating means for pressure-contacting the end surfaces of the two rubber sheets respectively held by the first and second holding means by moving the second holding means relative to the first holding means. Mutually facing surfaces of the first and second holding means are respectively provided with holder portions which are formed as rugged portions each taking a comb tooth shape and which are able to partly overlap to mesh with each other.

Abstract: A carcass ply is built on a forming drum by application of a plurality of strip-like elements by the steps of: setting a width of these strip-like elements, setting a width of the overlapped part between two adjacent strip-like elements, setting a fitting diameter of the forming drum by calculating a corresponding extension of a radially external laying surface, and calculating a whole number of strip-like elements to be applied. The whole number of strip-like elements is applied by rotating the forming drum around a geometric rotation axis thereof, and applying pairs of strip-like elements by means of a first laying unit and a second laying unit located close to opposite portions of the forming drum relative to the geometric rotation axis.

Abstract: An unvulcanized rubber member passed from the transfer terminal end of a liner to the outer peripheral surface of a winding roller is transferred and press-fitted to a winding body by rotating the winding roller. By this, the unvulcanized rubber member is transferred from the transfer terminal end of the liner to the winding body while being restrained by an outer peripheral surface of the winding roller. Thus, even if vibration is applied to a transfer means due to a diagonal waving, the winding position and the wound shape of the rubber member can be maintained substantially unchanged.

Abstract: The invention can surely accomplish lamination without the generation of voids in building a tire constructed to comprise a plurality of rubber members for a tire when a ribbon-shaped rubber strip (R) is spirally wound and laminated, and uses holding rolls (30) and two sets of stitching rolls (40a), (40b) arranged in parallel with a center of a rubber strip width (W) therebetween to enable performing of an independent pressing motion, such that the rubber strip (R) is pressed and bonded by the holding rolls (30) in a position, in which the rubber strip (R) is wound, and the stitching roll (40a) or (40b) positioned fore in an advancing direction of traverse movement, out of the two sets, is caused to perform a pressing motion in a regional part just after the press whereby a fore part of the rubber strip in the advancing direction is pressed and bonded.

Abstract: A tire building method and a tire building facility according to the invention attains reduction of an installation space of the tire building facility and substantially equal building cycles for respective building stages to increase building efficiency and facilitate arrangement switching. For attaining these, a step for building a cylindrical carcass band, a subsequent step for building a cylindrical green case, a step for building a cylindrical belt and tread band, a step for combining the green case and the belt and tread band to build the final shape are divided as first through fourth building stages (S1) through (S4) having individual building drums (D1) through (D4) corresponding to the respective steps.

Abstract: Tire-building apparatus and methods. The apparatus includes a mandrel over which tire components may be assembled and built into a tire. The mandrel includes a central cylindrical portion defining a crown supporting surface, a first frusto-conical portion defining a first sidewall supporting surface, and a second frusto-conical portion defining a second sidewall supporting surface. The crown supporting surface, the first sidewall supporting surface, and the second sidewall supporting surfaces are arranged so that a radial cross section of the mandrel has a trapezoidal shape.

Abstract: A green tire is built on a rigid toroidal support externally having a forming surface of a conformation corresponding to an inner conformation of the tire. The built tire is removed from the rigid toroidal support and engaged on an expandable toroidal support which includes a bladder. The green tire engaged on the expandable toroidal support is introduced into a vulcanization mold and submitted to a vulcanization cycle.

Abstract: Two extruders are located at positions which are mutually shifted by 180 degrees around a rotation shaft of a rotary support, and are arranged at the same position in the rotation shaft direction of the rotary support, and each time the rotary support is rotated 180 degrees, the two extruders and the rotary support are caused to relatively move in the rotation shaft direction of the rotary support. In this manner, at least a portion of the pneumatic tire is molded by winding the rubber strip members onto the rotary support.

Abstract: The invention can surely accomplish lamination without the generation of voids in building a tire constructed to comprise a plurality of rubber members for a tire when a ribbon-shaped rubber strip (R) is spirally wound and laminated, and uses holding rolls (30) and two sets of stitching rolls (40a), (40b) arranged in parallel with a center of a rubber strip width (W) therebetween to enable performing of an independent pressing motion, such that the rubber strip (R) is pressed and bonded by the holding rolls (30) in a position, in which the rubber strip (R) is wound, and the stitching roll (40a) or (40b) positioned fore in an advancing direction of traverse movement, out of the two sets, is caused to perform a pressing motion in a regional part just after the press whereby a fore part of the rubber strip in the advancing direction is pressed and bonded.

Abstract: Adhering a belt edge tape to both respective side edge portions of the belt on the outer peripheral surface of the building drum by supplying a belt edge tape toward the outer peripheral surface of the building drum by pressing using an extruder which constitutes a supply device facing the building drum in an opposed manner and by pressing the tape to the building drum using a press roller on a leading side as viewed from a position where the tape is supplied in the rotational direction of the building drum, the building drum is rotated in the direction that end portions of the reinforcing cords on the side edge portion of the belt which constitutes a tape adhering side are positioned on a trailing side in the rotational direction of the building drum thus adhering the tape to the side edge portion.

Abstract: According to the present invention, in adhering a belt edge tape (1) which is interposed between belt layers of a tire, press rollers surely adhere by pressing the belt edge tape (1) to a building drum (D) while preventing the press rollers from being caught by end portions of inclined cords which constitute a belt.

Abstract: In tire manufacture, a belt structure is made by means of strip-like segments each including parallel cords incorporated into an elastomeric layer, which strip-like segments are sequentially laid down in mutual circumferential side by side relationship on a toroidal support.

Abstract: A production device of a rubber band body includes: an extruder; and a pair of rollers for rolling a rubber member from the extruder between rolling areas of rollers to form a rubber band body, wherein a rolling area of at least one of the pair of rollers is configured by a circumferential groove formed in the outer periphery surface of the roller and extending over the entire periphery.

Abstract: A non-pneumatic tire includes a plurality of springs. Each spring includes a first end portion, a second end portion, and an arching middle portion. Each spring is interwoven with at least one other spring thereby forming a toroidal structure extending about an entire circumference of the non-pneumatic tire. The toroidal structure is at least partially coated with an elastomer. One end portion of at least one spring is wrapped around a first bead structure adjacent a rim.

Abstract: A device for adjusting the delivery rate of a linear element. The device forms a delivery path for the linear element between an inlet to the device at a delivery rate that is substantially constant and an outlet from the device at a delivery rate that is variable and substantially periodic and varies the length of the path of the linear element in application of a predetermined periodic relationship. The device includes a plurality of pulleys movable in rectilinear translation periodically in sinusoidal manner.

Abstract: A process and an apparatus for building tyres for vehicle wheels includes assembling at least one tyre component through laying of strip-like elements disposed circumferentially close to each other on a deposition surface radially external to the forming drum, wherein laying of each strip-like element includes: radially moving the strip-like element close to the deposition surface; locking a central portion of the strip-like element against the deposition surface; and pulling the strip-like element in opposite directions starting from the central portion toward the opposite ends thereof, while the central portion is maintained in a locked condition against the deposition surface, so as to progressively lay down the strip-like element against the deposition surface.

Abstract: A process and apparatus for manufacturing tyres for vehicle wheels, includes building, on a toroidal support, a carcass structure including at least one carcass ply associated, at axially opposite end edges thereof, with annular anchoring structures, the building step of the carcass structure includes forming at least one reinforcing structure, operatively associated with the annular anchoring structures through deposition on the toroidal support of at least one reinforcing element along a predetermined curvilinear deposition path. The deposition of the at least one reinforcing element includes the steps of: cutting to size a piece of at least one reinforcing continuous band-like element fed by a feeding device along a predetermined feeding direction, deforming the piece obtained according to the curvature of a deposition part of the deposition path intended to receive the piece, and depositing the deformed piece at the deposition part.

Abstract: Provided is a device for forming a special giant all-steel radial OTR tire in a continuous process, the device comprising a first base guide rail, a second base guide rail, a headstock, a main building drum, a belt housing, a belt drum and an overhead rail. The first base guide rail and the second base guide rail are parallel to each other. The overhead rail comprising a first traveling unit and a second traveling unit are disposed above the first base guide rail and the second base guide rail. A method for forming a special giant all-steel radial OTR tire in a continuous process is also provided.

Abstract: The present invention provides a method of producing a tire component member, which method allows rubber strip pieces to be sequentially attached without forming a gap therebetween.

Abstract: A process and apparatus for manufacturing tires for vehicle wheels, includes building, on a toroidal support, a carcass structure including at least one carcass ply associated, at axially opposite end edges thereof, with annular anchoring structures, the building step of the carcass structure includes forming at least one reinforcing structure, operatively associated with the annular anchoring structures through deposition on the toroidal support of at least one reinforcing element along a predetermined curvilinear deposition path. The deposition of the at least one reinforcing element includes the steps of: cutting to size a piece of at least one reinforcing continuous band-like element fed by a feeding device along a predetermined feeding direction, deforming the piece obtained according to the curvature of a deposition part of the deposition path intended to receive the piece, and depositing the deformed piece at the deposition part.

Abstract: A pneumatic tire having an air permeation preventive layer formed by adhering a resin film containing thermoplastic resin as a main component thereof to a tire inner wall surface, wherein the resin film is laminated, as a narrow width slit film shape, with an elastomer and the resultant ribbon-shaped laminate is continuously and spirally wound in a tire circumferential direction so that the edges thereof partially overlap to thereby form the air permeation preventive layer, whereby a pneumatic tire having a light weight and superior air permeation preventive property, no splice openings of the air permeation preventive layer at the time of tire processing, and capable of shortening the processing time can be obtained as well as the production method thereof.

Abstract: The invention can efficiently provide a carcass member constituting a carcass layer of a radial tire, particularly, a carcass member a direction of a cord of which constitutes an angle of substantially 90° relative to a tire circumferential direction, and can easily adjust a length in accordance with a size, one piece of a cord (C) is continuously passed through a rubber coating die (14) to coat rubber on the cord, the rubber coated cord (C1) is shaped such that a sectional outer shape thereof constitutes an elliptical shape, the rubber coated cord (C1) is wound around an aligning drum (30) while adjusting a direction of the elliptical shape by way of an aligning guide (20) to bond without producing a gap to form a cylinder-like member (A1), thereafter, the cylinder-like member (A1) is cut in a direction in parallel with the drum axis center to constitute a sheet-like shape.

Abstract: Device for manufacturing a reinforcement from a thread laid directly in its final place by casting lengths of the said thread onto a receiving surface, the said device comprising a feed means (200) for feeding the thread (1) from a source of thread (10), a rotary assembly comprising a rotary guide (2) of axis rr? fixed to a hollow shaft (20, 205) constituting the axis of rotation (RR?) of the said guide (2) so that the outer radial end (21) of the said guide (2) is directed substantially radially with respect to the axis of rotation of the hollow shaft (RR?), the said guide receiving the thread (1) that comes from the said feed means via its central end (22) that is the opposite end to the said outer radial end (21), the said thread leaving via the said outer radial end (21), the said feed means controlling the linear speed at which the thread advances inside the said rotary guide (2), means (13, 131) for rotating the hollow shaft, and means (31) for cutting the thread, acting on the thread in such a way as t

Abstract: A rubber sheet jointing apparatus is provided with a first holding member for releasably holding a joint end portion of one of two rubber sheets; a second holding member provided movably relative to the first holding member for releasably holding a joint end portion of the other of the two rubber sheets; and an operating member for pressure-contacting the end surfaces of the two rubber sheets respectively held by the first and second holding member by moving the second holding member relative to the first holding member. Mutually facing surfaces of the first and second holding member are respectively provided with holder portions which are formed as rugged portions each taking a comb tooth shape and which are able to partly overlap to mesh with each other.

Abstract: A rubber sheet joining apparatus includes a cutting unit for cutting a ribbon of rubber sheet reinforced with cords to generate rubber sheet strips having different lengths; a sheet overlapping unit for overlapping and joining the rubber sheet strips having different lengths to make an overlapped and joined strip. First holding members hold a front end portion of a following overlapped and joined strip. Second holding members hold a rear end portion of a preceding overlapped and joined strip. Support guides movably support the first holding members relative to the second holding members. An operating unit moves the first holding members relative to the second holding members to butt-join the side surfaces of two successive overlapped and joins strips held respectively by the first holding members and the second holding members to generate a ply sheet.