Patent GB-1459454-A (GB)
Title: Method and device for continuous winding onto a spool and unwind ing from a spool of an endless band eg a cinematograph film  formed into a closed loop
Inventor: BOYER JEAN-PAUL
IPC: G11B15/67
Filed: 1973-12-07
Abstract: 1459454 Tape spools J-P BOYER 7 Dec 1973 [12 Dec 1972 3 Aug 1973 27 Nov 1973] 56771/73 Heading B8M [Also in Divisions F2 and G2] Apparatus in which an endless band is continuously wound on and off spools, comprises an internal spool 1 (Fig. 3) whose core 3 lies within the area bounded by the band as it passes between the spools and through an item of equipment and an external spool 2 whose core 3 lies outside the area. Both spools can act as the take-up or feed spool and whichever spool is functioning as the take-up spool receives one portion of the band from the equipment and one portion direct from the other spool so that the band is wound double. The band always passes through the equipment in the same direction and its passage is not interrupted when the function of the spools is reversed, i.e. when spool 1 becomes empty, the film is reattached to core 3 of spool 1, the direction of rotation of the spools is reversed and spool 2 becomes the feed spool. Tensioning and compensating rollers.-Rollers 9, 9<SP>1</SP> are mounted on slidable bracket 28 and move away from rollers 9a, 9b, 9c to take up the extra length of band formed when the final loop of band is unwound from a core. Rollers 10, 10<SP>1</SP>, 10<SP>11</SP> are mounted on a pivotable bracket 32 which pivots upwards to brake the receiving spool if the tension in the band from the equipment exceeds a predetermined value. The spools may be braked by urging a friction band into engagement with the spool or by declutching the spool drive. Loading arm and finger.-The band is attached to the cores 3 by a loading arm and finger 7. The loading arm, Fig. 12, comprises two tubes 7b, 7c interconnected by a spring 7h and fixedly mounted on a shaft 8 which is rotated to pivot the arm towards and away from the spools. Tubes 7b, 7c are also anticipated with respect to each other by tube 7b being pivotally mounted on a pin 7d carried by tube 7c, the pivotal movement being limited by surfaces 7g, 7f of a segment shaped portion 7e. The finger is a truncated cone 7a, rotatably mounted on a rod 7j carried by a block 7k mounted in the free end of tube 7b. The block 7k is biased to the end of the tube by a spring 7n. An electromagnet (22) acts on the arm adjacent shaft 8 to tilt the arm in a direction perpendicular to its pivotal movement to move the finger into and out of the plane of the spool cores. Shaft 8 is driven by a motor 45 through a crank system 53, 54, 55, Fig. 10. The operation of motor 45, electromagnet (22) and the drive motors of spools 1 and 2 is controlled by a series of cams 56, 49, 50, 59, driven by the motor 45, in conjunction with other contacts described below. Operation.-In Fig. 22 two strips of the band are being wound off spool 2, one strip passing to spool 1 and the other to the equipment. When the final loop becomes detached from spool 2 a spring biased microswitch (12, Fig. 5) housed in core 3 emits a pulse to motor 45. The pulse however is delayed until the extra length of band has been absorbed in loop b4, causing rollers 9, 9<SP>1</SP> to fall, and then rise again until they close a contact (28a, Fig. 9). This permits the pulse to reach motor 45 which is actuated and rotates shaft 8, swinging the loading arm so that the finger carries a loop of the band from the part b2 to an indentation 3a in the core 3. When the arm reaches this loading position the cams cause motor 45 to stop and the drive motors to spools 1 and 2 to stop and start respectively. The articulation of tubes 7b, 7c permits the end of tube 7b to rotate with the core so that the finger remains in the indentation until several coils of the band are wound on to the core. The electromagnet is then energized to tilt arm 7 and lift the finger out of the spool plane. Motor 45 again operates to move the arm back to a position in which it is on the side of the strip coming from the equipment remote from the feed spool 1. Finally the electromagnet is de-energized to return the arm to its await loading position. When spool 1 becomes empty an operation, similar to that set out above, takes place to reattach the band loop to the core 3 of spool 1.