Patent GB-734156-A (GB)
Title: A method of and means for the manufacture of hollow articles
Inventor: BERGSTROM KARL ERIK LENNART
IPC: B21D53/36
Filed: 1953-08-18
Abstract: 734,156. Making hose clamps. ALLMANNA BRANDREDSKAPSFFAREN AKTIEBOLAG. Aug. 18, 1953, No. 22708/53. Classes 83 (2) and 83 (4). Stamping; shearing.-A method of and means for manufacturing sleeveshaped or hollow articles, e.g. the worm casing for a hose clamp, having internal radii of curvature in two different planes is characterized in that two internal dies are moved towards each other to enter one at each end of a sleeve cut from a preferably drawn seamless tube said dies each having a semi-clyindrical portion and a plate-shaped part adjoining the non-cylindrical outer surface of said semi-cylindrical portion, one portion of the sleeve being pressed to shape between the plate-shaped part and a recess in a press tool whilst another press tool presses the remaining portion of the sleeve around the semicylindrical portion of the dies. A slide 3 is mounted on two vertical guide rods 2 fixed to the machine base 1. Pivotally mounted on a central hub 4 on the slide are the inner ends of two arms 6 carrying forming dies 5 each consisting of a semi-cylindrical portion 7 and an arcuate plate 8. Each of the arms 6 is hinged to a table plate 13 by means of a link 12. A press bar 16 carrying an expanding die 17 is pivoted to a lever 18 connected to a bracket 15 by a link 19, and to the slide 3 by an adjustable bar 20. Also connected to the lever 18 are two rods 21 which at their lower ends are connected to a bracket 22 forming part of a hydraulic piston working in a cylinder 23 controlled by a pedal (not shown). The expanding die comprises two levers 28 (Fig. 6) pivoted on an axle 27 the lower ends of the levers having recessed notches 29 for forming the worm casing of the hose clamp 9. The upper ends of the levers are spring-loaded against a plate 30 carried on the press bar 16 and the axle 27 passes through a spring-loaded plunger 33 upward movement of which causes the levers to swing outwards and the notches to move towards each other. Below the press bar 16 an adjustable die 36 is mounted on the machine base. The die 36 has a recessed portion 37 (Fig. 7) with an arcuate bottom and side walls 39 and inside the die is mounted a punch 40 having a rectangular end surface 41 the short sides of which have cutting edges 42 adapted to cut through the sleeve at the bottom 43 of the formed arcuate channel 11 (Fig. 14) for producing two inturned lips 44 for attaching the steel band 10b of the hose clamp. The lower end of the punch is pivoted to a lever 46 one end of which is pivoted at 47 on the machine base the other end carrying an armature 48 of an electromagnet 49. The switch (not shown) controlling the electromagnet operates at a predetermined pressure in the hydraulic cylinder 23. A device for feeding the sleeves into the machine comprises a swingable arm 51 having two leaf springs 52 between which each sleeve is held. In operation, the feeding arm carrying a sleeve swings into the space 53 between the free ends of the dies 5 and depression of the pedal (not shown) swings the lever 18 and moves the expanding die 17 towards the die 36 and also displaces downwardly the slide 3 which causes the dies 5 to be swung so that the portions 7 and plates 8 protrude into the sleeve and hold it in position whilst the feeding arm is swung back. The sleeve is then pressed down in the recessed portion 37 of the die 36 by means of the plates 8 thereby shaping the lower arcuate channel 11 of the casing. The expanding die 17 now reaches the sleeve and forms the channel 10 of the casing by pressing the sleeve around the semi-cylindrical portions, 7 of the dies 5. When a predetermined pressure is reached in the cylinder 23 the electromagnet 49 is energized to cause the punch 40 to press upwards and cut the lips 44 in the bottom 43 of the casing.