| 摘要 |
1,227,886. Mandrels for making pipes RECHERCHES ET APPLICATIONS DES PLASTIQUES DANS L'INDUSTRIE ET LE BATIMENT. 19 Aug., 1968 [17 Aug., 1967], No. 39563/68. Heading F2P. A radially expandible, and contractible, mandrel, which is adapted to be erected vertically for the manufacture of tubes, or tanks, of reinforced plastics by winding around the mandrel bands of fibre impregnated with polymerizable plastics material, is formed of a number of individual sectors each of which comprises a rectangular metal frame 1 with sides 2-5, cross-bar 6, and bracing bars 9, 10 and a second rectangular frame 7 perpendicular to the frame 1, and secured to the vertical centre line of a flexible metal sheet 12 which has L- section reinforced edges 17 with pairs of arcuate upper and lower stay-members 22, 23 and 35, 34 having series of holes 24 and 35 which are individually co-operable with holes respectively in corresponding brackets 21, 20 or 33, 32 on a side 2, or 3, of the frame 1 so that the curvature of the sheet can be adjusted. To erect a mandrel, the stay-members 22, 23, 34, 35 are adjusted so that each sheet 12 corresponds to the desired overall circumference, the sectors then being arranged side-by-side in circular formation and connected together by turnbuckle connections 50 which threadedly engage between adjacent pairs 28, 30 and 29, 31 of oppositely threaded pivotal brackets to leave gaps between the neighbouring sheets 13. Adjustable rods 40 are connected between pins 27 on brackets 26 on the sides 2 of the frame 1 and a base 44 placed on the ground on the axis of the completed mandrel. After bands, e.g. of fabric impreg-' nated with polymerizable resin, or glass fibre, have been wound tightly upon the mandrel and polymerized the connections 50 are shortened to reduce the circumference of the mandrel so that wound bands can be slid axially to allow the winding on of more bands. When the pipe, or tank, is completed the mandrel can be dismantled for withdrawal. |
