GB1457355A - Tape transport for magnetic recording with a rotating head - Google Patents

Abstract

1457355 Helical scan tape transports INTERNATIONAL BUSINESS MACHINES CORP 17 May 1974 [2 July 1973] 22198/74 Heading G5R A tape transport in which magnetic tape 12 is moved from a tape source 28 helically around a mandrel 10, which flanks the path of a rotating magnetic recording head 18, to a tape sink 24 has entry and exit tape guides 14, 22 respectively operable to compliantly guide the tape from the source 28 to the mandrel 10 and from the mandrel 10 to the sink 24 in such a way that pertur- bations in tape movement at the source and sink are decoupled from a section of the tape heli- cally wrapping the mandrel, and means providing a stable air bearing supporting the tape on the mandrel and operable so that the air bearing thickness between tape and mandrel is substantially constant with variations in tape tension and air bearing pressure. The tapes may be stored in cartridges 54 carried permanently in a carousel 46 or loaded and unloaded at stations 50, 52 respectively of the carousel which has a read/write station 48 whereat coupling 58 on rod 56 pushes the tape spool 28 from cartridge 54 to engage drive member 60. The tape 12 passes from spool 28 via guide 30, vacuum buffer chamber 32, guide 14, mandrel 10, with a rotor 16 carrying write head 18 and read head 20, and guide 22 to drive take-up spool 24 whereon the tape is retained by vacuum. Hydrostatic air bearing surfaces are maintained at mandrel 10 and at guides 30, 14 and 22. Guide 30 has two compliant guide surfaces 31, and guides 14 and 22 have fixed surfaces 41, (45), Fig. 2 (not shown) and compliant guide surfaces 42, 44. Similar fixed and compliant guides may be provided on the mandrel e.g. over 10 degrees or the whole of the tape wrap thereon. A second embodiment, Fig. 4 (not shown), omits guide 30 and buffer 32 and has 180 degrees arc-length mandrel entry and exit guides like guides 14 and 22. In a third embodiment, Fig. 5 (not shown), the tape is wrapped 720 degrees about a mandrel on which the tape is guided by a continuous fixed guide and a continuous compliant guide both positioned on the mandrel with a 720 degrees helical wrap therearound, the first and last 180 degrees of which wrap provide the entry and exit guides for the control transducing section of the tape wrap on the mandrel. The mandrel may alternatively be rotated to provide a hydrodynamic air bearing for the tape, or rotated and supplied with air to provide a combined hydrodynamic/ hydrostatic air bearing. An alternative mandrel has a previous first half fixed and supplied with air to provide a hydrostatic bearing, and a second half carrying the magnetic head is rotated to provide a hydrodynamic bearing, Fig. 11 (not shown).