axially opposing annular surface unnumbered of a counterbore 58 of the opening 31 appropriate o ring seals 60 61 are received in grooves unnumbered of the bead aligner wheels 27 28 respectively and are in sealing contact with the outer cylindrical wall 51 of the sealing sleeve 50 to thus seal the chamber c in the closed position of the platens 14 15 irrespective of the distance therebetween in fig3 the platens 14 15 and the associated bead aligner wheels 27 28 and matrices 25 26 are illustrated in their furthest relative position from each other the platens 14 15 are held locked in the closed position of fig3 by the threaded engagement of the end portion 45 of the shaft 32 within the threaded nut or sleeve 56 carried by the threaded end portion 47 of the shaft 33 an axial bore 62 is provided in the end portion 47 of the shaft 33 simply to accommodate the head 46 of the bolt unnumbered carried by the shaft 32 the threaded nut 56 is also locked to the threaded end portion 47 of the shaft 33 by a radial set screw pin or the like not shown thus after the platens 14 15 have been closed fig3 the handles 44 connected by the head 43 to the shaft 32 are simply rotated to thread the threaded end portion 45 of the shaft 32 downwardly into the threaded nut 56 to thus lock the platens 14 15 in their closed position thus as is shown in fig3 the chamber c is sealed by the sealing sleeve 50 and the platens 14 15 are held in their locked position by the coupled engagement between the threaded end.