MAGNETIC TAPE POSITION SENSING

• US 3,861,619 A
• Filed: 11/02/1972
• Issued: 01/21/1975
• Est. Priority Date: 11/02/1972
• Status: Expired due to Term

• Current Assignee: Robert E. Wolff
• Original Assignee: Robert E. Wolff
• Inventors: Wolff, Robert E.
• Primary Examiner(s): Christian, Leonard D.
• Application Number:
  US05/303,096
• Time in Patent Office: 810 Days
• Field of Search: 242/55.19A,188,197-200 179/1.2S,1.2Z 346/78
• US Class Current: 242/333.2
• CPC Class Codes: G11B 15/08 by photoelectric sensing G11B15/07 takes precedence
• CPC Class Codes: G11B 15/26 Driving record carriers by members acting directly or indirectly thereon G11B15/44 takes precedence; driving features inside container, see G11B23/04 and subgroups
• CPC Class Codes: G11B 23/087 using two different reels or cores
• CPC Class Codes: G11B 23/34 Signal means additional to the main recording track, e.g. photoelectric sensing of sprocket holes for timing

Abstract

A length of magnetic tape extending along a tape path in a cartridge shell and having its ends wound one on each of a pair of reel hubs is formed adjacent each end with a repetitive pattern of holes. The patterns of holes at the two ends of the tape are different to distinguish the ends from each other and two additional sets of holes located more centrally of the length of tape than and distinguishable from the repetitive patterns demark the ends of the desired recording area on the length of magnetic tape. A plurality of photocells are used to detect the holes and to distinguish the repetitive patterns of holes from each other and from the additional sets of holes to provide unambiguous sensing of the beginning of tape, the end of tape and the desired recording area.

Claims

1. A magnetic tape recording and/or reproducing system comprising:

a cartridge shell defining an enclosure, a pair of reel hubs supported within said enclosure, a length of magnetic tape extending along a tape path within said enclosure and having its ends wound one on each of said reel hubs, said length of magnetic tape being formed adjacent each end with a repetitive pattern of holes, said patterns of holes at the two ends of said tape being different to distinguish the ends of the tape from each other, and said length of magnetic tape being formed with two additional sets of holes more centrally of said length of tape than and distinguishable from said repetitive patterns, one said additional set of holes being associated with each end of said length of tape, said additional sets of holes together demarking the ends of the desired recording area on said length of magnetic tape, means for moving said magnetic tape along said tape path from one of said reels and onto the other, a magnetic transducer for recording and/or reproducing magnetic signals on said magnetic tape as it is moved along said tape path, and means for detecting said holes in said magnetic tape and for distinguishing said patterns from each other and from said additional sets of holes to distinguish the ends of said length of tape from each other and from the desired recording area.

2. The magnetic recording system of claim 1 wherein said means for detecting said holes comprises a mirror positioned within said enclosure adjacent said tape path, a lamp positioned to transmit light to said mirror to be reflected therefrom against said tape and a plurality of photocells positioned to detect light reflected by said mirror against said tape and transmitted through said holes.

3. The Magnetic recording system of claim 1 wherein said holes in each said pattern and each said set are in a line across the width of said tape.