Patent GB-1488490-A (GB)
Title: Magnetic tape video recording and/or reproducing apparatu
IPC: G11B15/665
Filed: 1974-11-15
Abstract: 1488490 Video magnetic tape recorders TEAC VIDEO CORP 15 Nov 1974 [17 Nov 1973] 49514/74 Heading G5R A video magnetic tape recorder/player comprises a main chassis 1 on a major surface 2 of which are mounted drive members 37, 38 for reels 17, 18 in a tape cassette M, members 43 to 46 for supporting the cassette M, and a subchassis 5, first (51) and second (52) mounting surfaces being formed unitarily with subchassis 5 and with a portion (50) thereof contacting chassis 1, Fig. 4C (not shown); a rotary ring tape threader 93 rotating between first and second positions to wrap a loop of tape around a rotary head drum assembly 60; and first 70 and second 80 means defining the wrapping position of the tape loop about drum assembly 60; the surface (51) of sub-chassis 5 supporting the drum assembly 60 so that the plane of rotation of the head(s) therein is at an agle to the main chassis surface 2, and the surface (52) supporting the position defining means 70 at right angles to surface 2. Heads (65), (66) in drum 60 rotate in a plane at about 5 degrees to the major surface 2 of chassis 1, the drum assembly 60 being mounted on flat members (51-1) to (51-3), Figs. 4A to 4C (not shown), of sub-chassis 5 in a plane which is at 5 degrees to chassis surface 2 and lies perpendicular to an imaginary plane S1 containing line L1 and perpendicular to chassis surface 2. The ring 93 rotates in a plane at about 10 degrees to chassis surface 2, the ring 93, a control signal head 83, a capstan 131, the second position defining means 80-comprising guide pins 86, 87-and tape guide mechanisms 111-1 to 111-3 being mounted on flat members (53-a) to (53-e) of sub-chassis 5 on planes at 10 degrees to chassis surface 2 and lying perpendicular to an imaginary plane S3 containing line L3 and perpendicular to chassis surface 2. The first position defining means 70 comprises guide pins 74, 75 supported together with a video erase head 78 on a bridge 73 mounted by pins (71), (72) on flat members (52-1), (52-2), Figs. 4A, 4B, of sub-chassis 5 which are parallel to surface 2. In the inoperative position with ring 93 in its first position with an engaging member 97 in a recess 95 of ring 93, a spring biased arm 101 pivoted thereon is engaged by a stationary cam 103 to urge pin 106 and pinch roller 98, both on arm 101 and projecting into tape cassette M through opening 36, towards the rear of cassette casing 30, and a guide pin 149 on a tape tension control arm 144 also projects into casing 30 because a spring 154 causes arm 144 to engage part 155 of an arm 151 urged against stop 153 by spring 152. The opposite end of arm 144 to pin 149 is secured to a brake band 146 around a drum 141 of tape supply reel 17 drive shaft 37 To wrap the tape about drum surface 67, ring 93 is rotated clockwise by roller 110 whereby the tape is engaged by pinch roller 98 and curved surface 107 of pin 106 to draw a loop from cassette M. Each of the guide mechanisms 111-1 to 111-3 has a rotary shaft 116 carrying a tape guide pin 117 and a rod (119), Fig. 2 (not shown), carrying a roller (118) urged against the lower side of ring 93. As a hole 108 in ring 93 passes mechanism 111-1, roller (118) engages in hole 108 and then rides out therefrom, whereby the pin 117 is raised from a position parallel to ring 93 to an upright position within the withdrawn tape loop. The other pins 117 are similarly raised as hole 108 sequentially passes mechanisms 111-2, 111-3. As ring 93 reaches its second position member 97 engages in ring recess 96 and a pin 157 on ring 93 pivots arm 151 from stop 153 so that pin 149 lies adjacent pin 75 to control tape tension with the aid of brake band 146. In the loaded position the withdrawn tape loop extends from supply spool 17, around pin 149, across pin 75, head 78 and pin 74, around approximately 180 degrees of surface 67 and then across pins 86, 87 and head 83, between capstan 131 and pinch roller 98, around pins 106, 109 on ring 93 and then around pins 117 back to the take-up reel 18. To unload the tape, ring 93 is rotated anticlockwise from its second position to effect the above sequence of operations in reverse order.