Bag bottom shaping device

摘要

726,617. Making bags. ST. REGIS PAPER CO. June 11, 1953 [July 11, 1952], No. 16154/53. Class.94 (2). The apparatus described in Specification 706,860 is provided with an improved tube end spreader means for forming the bag bottom. Flattened bag tubes which are fed by a conveyer 27, are slit at the ends and suitably scored, and have the ends bent up at right angles to the main body of the tube. The tube ends are then opened by a suction device and the tube is fed to the spreader unit which comprises pairs of spreader arms 32a, 32b, pivotally secured between a pair of endless chains 33a, 33b. A pivotally mounted, grooved guide, comprising a horizontal portion 34a, and inclined portions 34b, 34c, co-operates with follower arms 40, 41 which are fixed to the arms 32a, 32b, which are thus moved linearly with the bag tube and simultaneously moved angularly to fold the bag bottom. A plurality.of pairs of spreader arms may be mounted on the chains 33. The centre guide portion 34a is movable in a vertical direction to engage the spreader tips 72 simultaneously with the tube end corners, by means of bell cranks 83 and 84, which are interconnected by a rod 89, adjustable by means of a turnbuckle 90, a follower 94 on one arm of the bell crank 84 co-operating with a cam 91. The spreader arms 32a, 32b, have additional follower arms 61, 62 respectively, which co-operate with a further guide member 35 provided with arcuate portions 35a, 35b. Retractible spreader fingers 65, 66, Fig. 6, are pivotally mounted between the bifurcated end 32b1, 32b11 of each spreader arm, by means of pins 67, 68, angular movement being restricted to about 15 degrees by a spring-loaded stud 69 having a conical tip engaging in a recess in the frame 64. The fingers 65, 66 are connected through links 76, 77 to the frame 64, and are pivotally connected at 65a, 65b to a member 72 which is attached to a spring-loaded plunger 73 movable axially in the frame 64. The spreader fingers are initially retracted, but when the device is inserted in the open end of the bag tube and the tip 72 engages the corner thereof the movement of the arm 32b forces the frame 64 to the right and spreads the fingers 65, 66, to form the corner and side flaps for the bag bottom. To return the spreader arms 32a, 32b to their initial unspread condition prior to their withdrawal from the tube end, an arm 96 connected to the bell crank 86, co-operates with a cam 92, a pair of guides 97, 98 holding the spread tube end while the arms are withdrawn. The spreader unit is adjustable to accommodate different sizes of bag tubes. Specification 677,256 also is referred to.