| 摘要 |
996,770. Moulding concrete pipes. G. A. POITRAS. Oct. 16, 1963 [Oct. 16, 1962; Jan. 10, 1963], Nos 39069/62 and 1110/63. Heading B5A. A mould for forming the spigot end of a concrete pipe in conjunction with a conventional pipe mould comprises a ring mould in which a circumferential groove forming component is mounted, means being mounted on the ring mould to impart limited radial expanding and contracting movement to the groove forming component. This arrangement allows easy removal of the ring mould from the pipe when the concrete has set sufficiently to maintain its shape. In the preferred embodiment shown the groove forming component comprises a plurality of segments 54, 55, 56, 57 pivotally mounted between the plates 41, 43 of the ring mould 39. The segments are moved between a groove forming position and a retracted position by the hydraulically or pneumaticallyoperated piston and cylinder assemblies 61, the movement being limited by stops 64 and 62 respectively. Gaps between segments 54, 55 and 56, 57 to permit the pivotal movement are bridged by resilient bridging portions, e.g. of rubber. To position and locate the ring mould 39 on the pipe mould 51 a plurality of lugs 52 are provided on the lower plate 41. In a further embodiment the groove forming component is an outwardly biased split ring which is moved between the groove forming and retracted positions by a manually-operated toggle mechanism.
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