A CARCASS FORMING DRUM

Abstract: The invention relates to a carcass forming drum es­ sentially comprising a pair of symmetrically located shoul­ der former including a plurality of sector pieces which are expandable and contractive in the radial direction. The car­ cass forming drum D according to the invention includes a pair of symmetrically disposed bead lock turnup devices D₁ and D₂ and a pair of symmetrically disposed shoulder for­ mers D₃ and D₄ located inward of said devices D₁ and D₂.

Description: The present invention relates to a carcass forming drum. US-A-42 26 656 show a tire carcass assembly with the features mentioned in the first part of the present claim. In detail the shoulder farmers as well as the bead lock seals are both radially movable. This is, however, effected without any axial pressure on the bead lock seal and therefore the material to be treated is not pressed or maintained in direct contact with the bead lock seals. For a better understanding of the present invention, some general information is useful. As is well known, a conventional method of manufacturing a radial tire is generally classified into a single stage type molding method and a double stage type molding method. The single stage type molding method is practiced by way of the steps of first winding a material for a carcass layer on a drum device which is designed so as to expand and contract, placing bead cores at the predetermined position, allowing the draumdevice to expand so as to deform the cylindrical configuration into a trochoidal one, and then winding a breaker ply and a tread thereon or allowing the carcass layer to expand to the inner wall of a breaker-tread structure which is previously prepared. On the other hand, the double stage type molding method is practiced by way of the steps of assembling a cylindrical carcass layer on a drum device in the first stage, said drum device being designed so as to expand and contract, removing the carcass ply from the drum device to transport the same, placing the carcass layer on another drum device in the second stage, said drum device being designed so as to expand and contract, deforming the cylindrical configuration of the carcass layer into a trochoidal one and then winding a breaker ply and a tread or allowing the carcass layer to expand to the inner wall of a breaker-tread structure which is previously prepared. As is apparent from the above description, the single stage type molding method is free from the trouble-some operation in the double stage molding method which comprises the step of displacing the cylindrical carcass layer from the drum device in the first stage to the drum device in the second stage, but it includes a number of problems because it is necessary to exactly locate a material to be assembled and effect firm assembling under pressure. Further, another disadvantageous feature of the single stage type molding method is that a distance between the adjacent cords is not distributed uniformly in the peripheral direction while the carcass ply is kept in an expanded state, because the carcass ply is expanded and comes in tight contact with the lower part of the bead cores, after the latter are placed on the cylindrical carcass ply. The invention is then directed to a special carcass forming drum which makes it possible to overcome the prior disadvantages of these drums. The carcass forming drum D includes a pair of symmetrically disposed bead lock turnup devices D₁ and D₂ and a pair of symmetrically disposed shoulder formers D₃ and D₄ located inward of said devices D₁ and D₂, as illustrated in Figs. 1 (a) to (d). Fig. 1 (a) (upper half above a line X - X) illustrates that the shoulder formers D₃ and D₄ are folded inwardly and the bead lock turnup devices D₁ and D₂ are spaced by the longest distance from one another. Fig. 1 (b) (lower half below the line X - X) illustrates that the shoulder formers D₃ and D₄ are expanded and the bead lock turnup devices D₁ and D₂ are located closer to one another than in Fig.1(a). Fig.1(c) (upper half above the line X - X) illustrates that the shoulder formers D₃ and D₄ are expanded and the bead lock turnup devices D₁ and D₂ are located closest to one another. Fig.1 (d) (lower half below the line X - X) illustrates that the bead lock turnup devices D₁ and D₂ are located closest to one another and the shoulder formers D₃ and D₄ are folded inwardly. The bead lock turnup devices D₁ and D₂ includes a sleeve 101 slidably mounted on a shaft 100 which is rotatably supported on a stand (not shown), an expandable bead lock seal 103 fitted into a circular groove on the periphery of a disc 102 radially extending from the sleeve 101 and an expandable bladder 104 disposed on a cylindrical extension from the disc 102 respectively. The bead lock seal 103 is preferably integral with the bladder 104 but the former may be separated from the latter (in the illustrated embodiment the former is integral with the latter). An arrangement is made such that both the bead lock seal 103 and the bladder 104 are supplied with pressurized air from the outside. As long as a so-called single bladder is employed for the bladder 104 as shown in the drawing, pushing devices are required. The sleeve 101 is operatively connected with a screw rod 105 via a nut 106 and a pin 107, said screw rod 105 being rotatably disposed within the shaft 100 while said nut 106 being in screw engagement with the screw rod 105. and said pin 107 extending through a slot 100 a formed on the shaft 100. A difference between both the bead lock turnup devices D₁ and D₂ consists in that the screw rod 105 and the corresponding nut 106 are threaded in the opposite direction to one another. Besides this there is no difference therebetween. As the screw rod 105 is rotated, the bead lock turnup devices D₁ and D₂ move toward one another in a symmetrical manner relative to a center line Y - Y of the drum, whereas as it is rotated in the opposite direction, they move away from one another. Further, as the bead lock seal 103 is supplied with pressurized air, its outer diameter becomes enlarged and thereby it is brought in pressure contact with the lower portion of the bead core fitted into a carcass band. As a result an airtight chamber is provided between both the pressure contact portions. It should be noted that the sleeve 101 is fitted with an air seal member (not shown) so as to ensure no leakage of air through a clearance between the shaft 100 and the sleeve 101 during sliding movement of the latter. The shoulder formers D₃ and D₄ includes a disc 114 slidably mounted on the sleeve 101 for the bead lock turnup devices D₁ and D₂, a plurality of hydraulic cylinder units 108 of which one end is fixedly secured to the disc 114 and of which other end is fixedly secured to the disc 102, a plurality of rods 109 fixedly secured to the disc 114 to extend through the disc 102, a plurality of links 111 of which one end is connected to the free end of the rod 109 and of which other end is connected to the central part of a link 110 pivotally mounted on the sleeve 101, a plurality of links 112 pivotally mounted on the sleeve 101 in the same manner as the links 110, and a plurality of shoulder segments 113 with the upper end of the links 110 and 112 connected thereto respectively, said rods 109 being fitted with an air seal member (not shown) in order to ensure no leakage of air from the air chamber during sliding movement thereof. As is apparent from the drawings, the links 110 and 112 have pivotal ends which form four corners of a parallelogram. As the disc 114 is displaced away from the disc 102 by means of the hydraulic cylinder units 108, the shoulder segments 113 are caused to expand. When they are expanded to the outermost limit, a cylindrical configuration is generated by them so as to allow the side wall portions to be tightly secured in the vicinity of the bead cores.

Claims: In a carcass forming drum comprising the right hand and left hand carrier means comprising a shaft (100) and sleeves (101) slidably mounted on said shaft, the sleeves supporting the different elements (103, 104, D₃, D₄) which are moved axially along an axis (X, X) so as to move toward or away from each other in synchronous and mirror symmetrical relation ship (Y, Y) , said carcass forming drum essentially comprising a pair of mirror symmetrically located shoulder formers (D₃, D₄) including a plurality of circumferentially mounted sector pieces (113) which are expandable and contractive in the radial direction perpendicular to the axis (X, X), a pair of mirror symmetrically located bead lock seals (103) located in the axial direction outwardly of said shoulder formers (D₃, D₄), said bead lock seals (103) being also expandable and contractive in the radial direction perpendicular to the axis (X, X) and a pair of mirror-symmetrically located turnup bladders (104) in the axial direction (X, X) located outwardly of said bead lock seals (103), said turnup bladders (104) being expandable in the radial direction perpendicular to the axis (X, X), in which the left hand shoulder former (D₃) moves toward or away from the right hand shoulder former (D₄) in synchronous and in mirror symmetrical relationship, and the bead lock seal (103) on the left hand side moves toward or away from the bead lock seal (103) on the right hand side in synchronous and mirror symmetrical relationship, and the left hand turnup bladder (104) moves toward or away from hte right hand turnup bladder (104) in synchronous and mirror symmetrical relationship, characterized in that each shoulder former (D₃, D₄) is connected via a pair of first links (110, 112) with the corresponding sleeve (101) and that said first links (110) are connected via a plurality of second links (111) and rods (109) with a disk (114) slidably mounted in axial direction sleeve (101) the disk (114) being moved by a plurality of hydraulic cylinder units (108) one element of which cylinder unit being fixedly secured to said sleeve (101).

Inventors: NOBUHIKO IRIE C/ONAGASAKI SHIPYARD/ENGINE WORKS
Applicants: MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1982
Main classification: B29D30
IPC codes: B29D30, B29C67