| 摘要 |
944,465. Film extrusion orifice. E. I. DU PONT DE NEMOURS & CO. Sept. 24, 1962 [Sept. 25, 1961], No. 36206/62. Headings B5A and B5B. An adjustable mechanism for a flat-film extrusion orifice comprises a body member 6 having an adjustable lip 3 slidably fixed thereto, a rigid lever-arm 1 having a cylindrical opening therein fixedly attached to the adjustable lip, a bendable support member 4 fixedly attached to the body member and the lever-arm to form a fulcrum about which the lever arm can pivot, a threaded cylindrical stud 7 projecting from the body member in alignment with the opening, a nut 2 having a skirt provided internally with threads, the nut and skirt being in threaded engagement with the threads of the stud, and resilient means, e.g. a spring 5 between the body member and the lever-arm adapted to maintain a constant contact between the threads of the nut and skirt of the stud. As shown, the body member is preferably U- shaped. Spring 5 may be a coil spring, cantilever spring or may comprise axially mounted frusto-conical disc springs. The mechanisms may employ a lever of the first class, as in Fig. 1, or of the second class as in Fig. 2, the latter being more convenient for increasing the theoretical mechanical advantage in a confined space. In the Fig. 2 apparatus, the support member 4 extends beyond the lip 3 and is attached to the end of the lever arm 1 by cap screw 15. Opening 16 is slightly larger than stud 9 to permit free movement of the stud as the lip is adjusted, and a gap 17 is maintained between lip 3 and support 4 to permit the desired travel of the lip. A number of mechanisms may be arranged along the adjustable lip of the extrusion orifice. In operation the adjusting screw 2 is driven over threads 8 of the stud 7 to move lever arm 1 in the appropriate direction to effect the desired movement of adjustable lip 3. Motion of lever-arm 1 at screw 2 is transmitted as motion of lesser displacement to bendable lip 3 by pivoting of the lever arm around the fulcrum formed by support member 4. Loading spring 5 maintains compressive contact between the lever arm and the threads of stud 7 which is rigidly fixed to body member 6, the upper-portion of which is U-shaped, in order to eliminate backlash and provide immediate positive response at bendable lip 3 to rotation of the screw 2. Lip 3 is slidably affixed to body member 6 by stud 10, elongated channel 11 providing for the opening and closing motion of the lip. Spacer 12 provides for reduced friction and assists in forming a seal between lip 3 and body member 6. The lip is affixed rigidly by stud 9 to lever-arm 1. Coarse adjustment of the lip opening may be made by nuts 13 and 14. The adjustment mechanism is especially intended for automatic control, by, for example, reversible electric motors. U.S.A. Specifications 2,790,945 and 2,829,268 are referred to.
|
