Patent GB-1474736-A (GB)
Title: Reel assemblies for automatic threading apparatus of magnetic tape recorders
IPC: G11B15/61
Filed: 1974-06-05
Abstract: 1474736 Reels; tape cassettes SONY CORP 5 June 1974 [5 June 1973] 25025/74 Heading B8M [Also in Division G5] A reel assembly 7, Figs. 1 and 16, for an automatic threading apparatus of a magnetic tape recorder has a drawing tape 26, Fig. 5, connected at one end to a reel hub 127 and windable therearound between flanges 129a, 129b, Fig. 16, the other end of the tape 26 being secured to a connector 29, Fig. 5, for releasably gripping a tape member, such as a leader 22, Fig. 16, of a magnetic tape 20, and the hub 127 having a cut-out 130 to receive connector 29 so that on rotation of the reel assembly in the winding direction drawing tape 26 is wound on hub 127 between flanges 129a, 129b, connector 29 is then received in cut-out 130 and leader tape 22, which is wider than the tape 26 and the spring between flanges 129a, 129b, is wound around flanges 129a, 129b and between flanges 128a, 128b and circularly circumscribes connector 29 in cut-out 130. The flanges 128a, 128b and parts of flanges or hubs 129a, 129b have cut-out portions leading into the cut-out 130. A takeup reel drive motor 140 is connected to a cylindrical member 135 fitting into hub 127. The connector 29, Fig. 5, comprises member 30, 31 pivoted on a shaft 33 carrying rollers 36a, b, 38a, b and a spring urging projections 35a, b on member 31 into recesses in member 30, projections 35a, b engaging through respective apertures 39a, b in the leader 22. A tape cassette 6, Figs. 10, 11, houses a tape supply reel 5 comprising a central boss 64 in a hub 62 carrying flanges 63a, b. The leader tape 22 is wound in annular gaps between the periphery 63a<SP>1</SP>, b<SP>1</SP> of flanges 63a, band guide rings 78a, b. When the cassette is not mounted on the recorder a spring 77 acts via a thrust pin 76 thrust block 74, thrust bearing 73, and a cylinder 72 to urge the reel 5 downwardly so that flange 63b engages base 79b of ring 78b and so that teeth 83 on a lever 81 engage with ratchet teeth 84 of a disc 68 to prevent rotation of the reel 5, On mounting the cassette on the recorder, a cylindrical member 110 of the supply reel holder 3, driven by motor 116, is inserted into boss 64 and driving pins 112 engage in holes 71 of boss 64 and the reel 5 is lifted to disengage parts 63b, 79b. Simultaneously positioning pins 118a, b engage through bottom apertures 61a, b of the cassette, pin 118b acting on lever 81 to disengage teeth 83, 84, and a gear 119 enters through opening 103 to engage a gear 102 whereby a motor (not shown) may drive via belt 122, gears 102, 119 and belt 101 to rotate a roller 93 and thereby drive the leader tape 22 via guides 97, 102 out of the tape inlet/outlet opening 92 of the cassette. The magnetic tape 20 has a wider leader 22, the upper and lower halves of the leading portion of which are respectively opaque and transparent with the upper and lower halves of the remaining part of the leader being respectively transparent and opaque, and an equal width trailer tape having upper and lower halves which are respectively opaque and transparent. The tape deck, Fig. 1, includes a device 17, located between flanged tape guide rollers 11a, b, to operate connector 29, an audio erase head 14, an audio and/or control head 15, a video erase head 16, a helical storing drum 2 providing a 180 degree tape wrap and rotary video heads 2a, 2b, capstan 8a, b, pinch rollers 9a, b and further tape guides 11c to 11g 12a, b and 13a, b. Movable pins 55a, b operate to prevent connector 29 contacting heads 14, 15, 16. Each of the guides 11c to 11g has a central shaft (43), Fig. 7 (not shown), guiding the magnetic tape 20, inner rollers (44a, b) on the ends of shaft (43) to guide the leader 22, and outer roller (45a, b) to engage rollers 36a, b of connector 29. The drum 2, Figs. 8, 9 (not shown) has a helical path (48a), (49a) for tape 20 defined between guide surfaces (52a<SP>1</SP>, b<SP>1</SP>) of guides (52a, b). Guides (52a, b) engage the leader tape to prevent contact thereof with path (48a), (49a) and further guides (51a, b, engage rollers 36a, b of connector 29 to prevent the latter contacting said helical path. Automatic tape loading (threading) is initiated by operating a control button so that reel 7 is rotated to unwind the drawing tape 26 until connector 29 is caught by a holder 145 of device 17 and engages between a block (157), Figs. 17 to 22 (not shown), and a spring biased lever (158) whereby projections 35a, b are disengaged from member 30. Operation of said button also causes roller 93 to be driven to draw the leader 22 out of the cassette 6, leader 22 being guided into holder 145 by guide plates (144a, b). Immediately before the leading end of the leader contacts stopper members 32a, b of connector 29, a solenoid 156 is operated to move lever (158) thereby allowing the spring of connector 29 to engage projections 35a, b through apertures 39a, b in the leader to connect drawing tape 26 and the leader. Reel 7 is then driven by motor 140 to draw out the leader 22 at the same speed as roller 93, the leader 22 following tape 26 in the path 10 between cassette 6 and take up reel 7 via drum 2, motor 140 and the motor of roller 93 being stopped when the trailing end of leader 22 is adjacent guide 11g. On pushing an unloading button motor 116 drives supply reel 5 until connector 29 reaches device 17 which, as solenoid 156 is deenergized at that time, automatically opens the connector. The loading/unloading sequences are controlled by photo-sensors S 1 , S 2  adjacent cassette 6 and sensing the upper and lower halves of the tapes respectively, and by a photo-sensor S 3  adjacent reel 7 and sensing the upper half of the tapes. Sensors S 1 , S 2 , S 3  also act to stop tape transport and energise a lamp in the event of tape breakage and act as end of tape sensors during fast wind/rewind, recording and playback. An alternative form of reel assembly 7 which is disclosed but which is not within the scope of the invention utilizes a pair of wires in place of the drawing tape 26, Fig. 4 (not shown).