Patent GB-1225483-A (GB)
IPC: G11B23/087
Filed: 1967-05-09
Abstract: 1,225,483. Tape cassettes and handling machines. ENGLISH NUMBERING MACHINES Ltd. 23 April, 1968 [9 May, 1967] No. 21396/67. Heading G5R. The spools of a magnetic, paper or optical tape cassette for a machine having parallel spool-driving spindles are prevented from rotation when not in use by engagement of a spring-loaded locking member engageable with a ring of teeth on each spool. In one arrangement (Fig. 2) the locking member is a plunger 6, biased by springs 10 and having a cross-pin 11. The plunger is engaged by a cam 46 on a receptacle door 44 to release the spools and allow a felt pressure pad 9 to move under spring force 16 and engage the tape with a head 60, a cam notch 14 retracting the pad when the plunger is released. The door includes a pawl 45 engageable with a label 48, indicating that the cassette has been used, to prevent the door closing. The spools are notched to engage with a pin on drive shafts or vice versa and windows are provided to view beginning and end-of-tape markings. In another arrangement (Fig. 8) spring-biased levers 151, 152 press on slides 146, 147 having teeth 149 engageable with teeth at one end of each spool, apertures 158 in each slide being engaged by cam-shaped ends 204 of the driving shafts 106, 107 to release the spools. The cassette has windows and a pressure pad as before, and an opening for a recording head 211 normally closed by slidable shutters 127. The spools contain spring-loaded pins 109 (Fig. 12), engageable with notches 210 in driving wheels 209 as the cassette is loaded into the apparatus. When loaded, the spools are released by the drive spindles, a spring-biased ejector pin 218 engages the cassette, and feelers 214, 215 sense the presence of the cassette. A sliding door 202 is closed to cover the cassette and causes the following operations: (a) Rollers 273, biased by spring plate 274, engage a cam (163, Fig. 9, not shown) on the cassette to urge it into the operative position. (b) If a label, indicating that the cassette has been used, is attached to the cassette, it engages a lug 277 on a rod (278, Fig. 13, not shown) which moves a spring (279) in a guide (280) so that it does not trip a microswitch 221, thereby indicating that the door is not fully closed. (c) A cam surface 268 on a slide (263) spring- loaded (266) to the right, is engaged by a roller 270 on a spring-biased bell-crank 271. (d) When fully closed, a lug 281 is engaged by the armature of a de-energized solenoid 282 to lock the door. A stepping motor 227 drives, via warm gear 225, the shaft (204) associated with the take-up spool and which also carries a freely rotatable spool 229 on which is wound a spring 231. Motion of the cassette feed spool 102 rotates a second spool 230 to wind up the spring 231 to provide constant back-tension on the feed spool 102. When recording nears completion, the motor 227 is stopped and a pawl (235, Fig. 15, not shown), which rides on the spring 231 as it is wound on to spool 230, moves a roller (241) out of the path of a projection (243) on a spring- biased locking lever (244) allowing the lever to move and thereby position a locking pin (247) adjacent a recess (248) in the ejector pin 218. The door is partially opened but the roller 270 still engages the slide (263) to tension the springs (266). On further opening, the roller 270 is freed and the slibe (263) is rapidly moved by its springs to disengage the rollers 273 from the cassette which is therefore partially ejected by the pin 218, the locking pin (247) retaining the pin 218 in this position. The cassette spools are disengaged from the drive shafts in this position and the spring 231 automatically rewinds on to the spool 231 under control of an escapement mechanism 256, 258. When fully rewound, the pawl (235) enters a notch (234) in the spool 230 to prevent over-winding and returns the locking lever (244) thereby allowing the ejection pin 218 to fully eject the cassette the door being fully opened during rewind of the spring 231. Modifications.-Either driving arrangement, if suitably modified, may be used with either form of cassette (not detailed).