Patent GB-890646-A (GB)
Title: Improvements in or relating to batch mixing machines for rubbers and plastic substances
Inventor: WATSON WILLIAM FERGUSON
IPC: B29B7/42
Filed: 1957-06-21
Abstract: 890,646. Batch-mixing machines. BAKER PERKINS Ltd. June 20, 1958 [June 21, 1957], No. 19620/57. Class 86. A batch mixing machine similar to that described in Specification 695,934 comprises a mixing chamber 42 through which extends a mixing blade 15 mounted on a driving shaft 1, the chamber being either cylindrical or frustoconical and provided with concave flutes or grooves extending longitudinally of the chamber to coact with similar grooves in the blade 15 to force treated material, such as rubber, towards the closed end of the chamber. A sleeve 2 surrounding the shaft 1 houses a ball-bearing race 4 and a carbon-bearing 6 for mounting the shaft, which is connected by means such as a gear wheel (not shown) to the driving power. A stuffing box 7, packing 8 and a gland ring 9 provide an air-tight seal between the shaft and the sleeve, a clamping ring 12 being used to force the ring 9 against the packing 8. An axial recess 16 in the shaft receives the spigot 17 of the blade 15, which is locked against rotation on the shaft by a pin 20, adapted to shear should the blade be overloaded. Sleeve 2 is held against rotation in a mounting sleeve 23 by a key 27 and restrained from free axial movement by a collar 25 having threads of opposite hands engaging the sleeve 23 and the enlarged end of sleeve 2 respectively. Capstan bars 29 are provided on the collar to adjust the relative axial positions of the chamber 42 and the blade 15. Lugs 30 at the end of sleeve 23 abut corresponding lugs 31 on the chamber housing 22 and are clamped together by a ring 34 having an internal channel 35 circumferentially interrupted to provide a bayonet-type joint with the lugs 30, 31. A member 36 closing the housing 22 has a reduced portion 37 which fits into the base of the housing. Conduits 39, 40 may be used to connect the chamber 42 to exhaust or compression pumps or to admit gases to the chamber. Conduits for heating or cooling means may be provided both in the chamber housing and in the blade. The chamber may be rotated and the blade held stationary or both may be rotated but at different rates. The chamber wall and base closure may be shaped to provide a concave end wall to the chamber. The machine may be arranged with the longitudinal axis of the chamber vertical or horizontal. To form the blade 15 a rectangular or trapezoidal blank may be twisted through 180 degrees so that its edges follow a helical path, generally of opposite hand to the grooves in the chamber wall. If the twist is in the same sense, the leads of the respective helices differ so that a downward movement of the material in the chamber is produced. Material may be added to the chamber, Fig. 3, through an opening 53 closed by a plug 54 held in place by a strap 55. The blade 15a is made by cutting a helical groove 58, Fig. 4, in a cylindrical blank, the groove being progressively shallower towards the base 59. Portions 61 outside the dotted lines 62 are then removed and the remaining grooves 58 are run out along the smooth surfaces thus exposed. Other modifications of the blade and chamber grooving are described.