Patent GB-775144-A (GB)
Title: Improvements in or relating to collapsible mandrels
Inventor: RUSSELL ROBERT GORDON
IPC: B21C47/30
Filed: 1955-01-25
Abstract: 775,144. Winding and reeling. DAVY & UNITED ENGINEERING CO., Ltd. Jan. 19, 1956 [Jan. 25, 1955], No. 2246/55. Class 83 (4). A collapsible water-cooled mandrel or drum comprises a rotatable shaft 1 with segments 8 mounted around it, means for transmitting torque from the shaft to the segments, for moving the segments radially and for locking them in their outermost position, and resilient means mounted to act between the segments and a fixed abutment to enable the segments to yield in the event of an abnormally large hoop stress in material coiled on the mandrel. The shaft 1 is hollow, is supported in bearings 3 and 4 and carries a driving pulley 2 at one end and the mandrel sections 8 at the other, where it is of square cross-section and is formed on each side with three wedge faces 10 each making an angle of fifteen degrees with the shaft axis and carrying a replaceable block 11 of bearing metal. Mounted on each side of the shaft is a mandrel section 8 with an arcuate outer face and a recessed inner face to which is screwed a block 12 formed with wedge faces adapted to ride on the faces 10 to alter the diameter of the mandrel as the sections are moved longitudinally with respect to the shaft. Beyond the wedge faces the shaft has four radial projections 14 shaped as shown in Fig. 7 with recesses 15, each inclined at the same angle as the wedge faces, along which the mandrel sections slide and by which they are anchored. Bearing metal inserts 19, 20 facilitate the movement of the sections. At their other ends the mandrel sections have portions 23 sliding in recessed slots 25 in the shaft, Fig. 6, with bearing metal inserts 24. When the shaft 1 rotates, the sides of the projections 14 and recesses 25 transmit the necessary torque to the mandrel sections. The axial movement of the mandrel sections along the shaft is effected by a rod 5 passing through the shaft and having at its outer end a cruciform plate 28 engaging within slots 30 in the sections and held in contact with a flange 32 on the rod by a spring 33 which normally keeps the segments in expanded condition. Movement of the rod to the right, as seen in Fig. 2, causes the segments to ride down the wedges 10 and contract. If, while fully expanded, the hoop stress on the mandrel becomes excessive, the segments can yield radially against the action of the spring 33. Movement of the rod 5 within the shaft 1 is effected by a double-acting piston and cylinder assembly 61 pivotally connected at 64 to two toggle links 57 and 63, the latter being pivoted to a part of the frame and the former to a lever 52 at 56. This lever is pivoted to the frame at its lower end 55 and at its upper end has a fork 50 embracing trunnions 48 on a cylinder 42, similar to the cylinder 42a shown in Fig. 8, slidable on shaft 1 and having a pin 43 fast in the rod 5 and passing through a slot 44 in the shaft 1 and into apertures in a sleeve 45 rotatable within the cylinder in bearings 46. In the fully expanded position of the mandrel, further movement of the rod 5 is prevented by the engagement of abutments 67, 68. In a modification, the arrangement shown in Fig. 8 is adapted, the rod being actuated by a piston and cylinder assembly 61a and contraction in the case of overload being against a spring 33a. The sides of the mandrel segments have projections 72 arranged so that those on one section interdigitate with those on the neighbouring segments throughout the whole range of expansion and contraction. In order to cool the mandrel water is pumped into a groove 77 in a sleeve 76 and then passes through passages 81 to grooves 82 formed in members 83, Fig. 4, fixed in the corners of the square part of the shaft and then into spaces 82b, finally escaping from the end of the mandrel.