Patent GB-734690-A (GB)
Title: Improvements in or relating to feed hoppers for film and sheeting production apparatus
IPC: B29C48/08
Filed: 1952-08-25
Abstract: <PICT:0734690/IV (a)/1> <PICT:0734690/IV (a)/2> <PICT:0734690/IV (a)/3> A feed hopper for use in making films or sheets comprises inclined walls terminating in a discharge slot for feeding a film- or sheet-forming solution from the hopper, a blade, or a pair of blades, each disposed in the hopper with its lower end adjacent to, and at one end of, the slot in engagement with one of the inclined walls, a "knee-action" connection between the upper end of the, or each blade, and adjusting means for moving the or each blade towards or away from the slot so that the thickness of one or both edges of the film or sheet can be controlled or predetermined by the position of the lower end of the blade or blades relative to the slot.  As shown in Fig. 4, the blade 29 has a lower end portion 30 positioned adjacent to or actually in the slot 16 formed between the lower ends 19, 20 of the hopper walls 17, 18.  The left-hand face 31 of portion 30 is inclined or tapered so that it is substantially parallel with the adjacent inner surface 32 of the hopper wall 17, and co-operates therewith to form the effective width of the discharge slot 16.  The blade 29 is connected to its operating and supporting shaft 33 (Figs. 4 and 5) through a "knee-action" mechanism comprising a T-shaped connecting member 44 which extends radially or laterally from the left hand end portion 42 of shaft 33 and is rigidly secured thereto.  The outer end 47 of the member 44 is pivotally connected to the blade 29 by means of the pin 50 so that the blade member 44 constitutes a "knee-action" connection between the blade and the portion 42 of the shaft 33. Rotation of the shaft 33 will thus cause the member 44 to move the blade in such a manner that in all positions of adjustment of the blade the inclined face 31 of portion 30 co-operates with the adjacent portion of the face 32 of wall 17 to form the effective width of the discharge slot 16.  In order that face 31 may be effective in controlling the width of the slot, the blade 29 is yieldably urged in a counter-clockwise direction (as viewed in Fig. 4) about pivot-pin 50 so as to retain face 51 of the portion 30 in positive engagement with the inner surface 52 of the wall 18 adjacent to the slot 16 for all positions of adjustment of the blade.  This is effected by a cantilever spring of which the arcuate portion 54 is secured to the portion 42 of the shaft 33 and the free end 55 projects between the links 48 of the blade and engages surface 56 of the blade (Fig. 5).  The reduced end portion 34 of the shaft 33 extends through an end wall 35 of the hopper (Fig. 6) and carries a worm wheel 36 in engagement with a worm-gear 37 carried by a shaft 38 to which is rigidly secured the adjustment hand wheel 39, so that by rotation of the latter the position of the blade may be adjusted from outside the hopper without the machine being stopped or the blade being handled.  The amount of rotation of the shaft 38 and hence the range of movement of the blade is limited by means of the nut 58 in engagement with a threaded portion 57 and limited in its travel on the latter by the shoulders 59 of the bracket 60 secured to the outer surface of the wall 35 of the hopper.  If the ends of the hopper are provided with corner pieces (not shown) in order to strengthen the hopper, the lower edge of the blade is bevelled, as shown at 61 (Fig. 5), to make it complementary in shape to such corner pieces, thereby permitting the blade to close the adjacent end of the slot when desired.