Tape driving means

987,721. Feeding record tapes. AMPEX CORPORATION. Dec. 19, 1962 [Jan. 2, 1962], No. 47971/62. Heading G5R. A magnetic tape 18 is threaded, Fig. 1, and driven in either direction (Figs. 2, 3, not shown) past heads 21-24 by air-pressure differentials, apart from the reel drives, past an antifriction support/guide surface 47. The surface may be of PTFE, but is preferably an air-bearing represented by the emergent air at intermediate pressure through a porous material such as "Oilite" (Registered Trade Mark). The upper walls 41, 42, 45, 46 are also made of this material and supplied with air to prevent tapesticking during threading. Hinged members 43 (Fig. 5) and 44, downwardly spring have either set of chambers 74, 75 connected to high pressure, the inclined outlets 49 threading and driving the tape forwards and elevating the members 43, 44 clear of the tape. Reelloading access is provided by doors 31, 32, the region 17 being otherwise sealed. Low pressure is connected to the take-up reel hub, Fig. 6, the slots 102 catching the leading end of the tape on threading, holes 110 taking over when the slots 102 are covered by tape. A mid-position of the switch 86 (Fig. 4, not shown) cuts off high-pressure air from both sets of chambers 74, 75 in the member 43, 44, which spring down to snub the tape. Buffer columns 111, 112, of usual type are energized after threading is completed.