| 摘要 |
<p>1,137,181. Injection moulding. LINK BELT CO. 11 Jan., 1966 [14 Jan., 1965], No. 1227/66. Heading B5A. [Also in Division F2] A valve in which a flexible sleeve 3 is twisted to close the flow passage by relative rotation between rings 1, 2 integral with the sleeve is formed by injection moulding, the material, which may be nylon, polyethylene, rubber or urethane, being introduced under pressure simultaneously through three nozzles 61, 62, 63 into a mould consisting of two semi-cylindrical halves 37 enclosing cores 48, 52 and 54 connected by a pin 57 and a bolt 58. The material flows from the ring-forming spaces into the sleeve-forming space and finally into bleed holes 64 when the injection pressure rises rapidly indicating that the mould has been filled. Cavities, such as that shown at 60, provide a reinforcing bead on the inner or outer surface of the sleeve where the twisting action is greatest. Projections 10 and recesses 12 interengage with a snap-action to hold the rings in rotatably assembled relationship, the recesses 12 being formed by ring halves 41 held in the mould by pins 42. The valve may be formed with two rings, instead of three, as shown.</p> |
