# US 5,345,355 A · Slack limiting tab for a magnetic tape cassette > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,355 A - Document ID: US5345355A - Status: Granted - Kind: A - Application number: 07/781,732 - Filed: 1991-10-23 - Granted: 1994-09-06 - Earliest claimed: 1991-10-23 - Assignees: Minnesota Mining and Manufacturing Company - Inventors: Vincent P. Teuber; Qing Cai - Web page: https://patentgrep.com/patent/US5345355A ## CPC - G11B 23/08757: {Guiding means} - G11B 23/08721: {Brakes for tapes or tape reels} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract The present invention provides a magnetic recording tape cassette comprising: a housing having an access area; two reels, rotatably mounted within the housing; a length of magnetic tape having opposite end portions wound around each of the reels and a portion extending therebetween; a tape guiding surface for guiding the tape portion in extension between the reels, across the access area, and along a predefined path between at least one of the reels and the access area; at least one slack limiting tab having a contact end portion and a mounting region; the slack limiting tab comprising a flexible, resilient polymeric material having a T.sub.g of greater than about 140.degree. C.; and mounting means in said housing for mounting said slack limiting tab in the housing such that the mounting region engages the mounting means, and the contact end portion is biased against the tape to press the tape against the tape guiding surface. ## Claims ### Claim 1 A magnetic recording tape cassette comprising: (a) a housing having an access area; (b) two reels, rotatably mounted within said housing; (c) a length of magnetic tape having opposite end portions wound around each of said reels and a portion extending therebetween; (d) a tape guiding surface for guiding said tape portion in extension between said reels across said access area, and along a predefined path between at least one of said reels and said access area; (e) at least one slack limiting tab having a contact end portion and a mounting region; said slack limiting tab comprising a flexible, resilient polymeric material having a glass transition temperature of greater than about 140.degree. C.; and (f) mounting means in said housing for mounting said slack limiting tab in said housing such that said mounting region engages said mounting means, and said contact end portion is biased against said tape to press said tape against said tape guiding surface. ### Claim 2 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab comprises a flexible, resilient polymeric material having a glass transition temperature of greater than about 150.degree. C. ### Claim 3 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab comprises a flexible, resilient polymeric material having a creep value of less than about 0.5% strain at 100 hours under a load of 7.0.times.10.sup.5 kg/m.sup.2 at 44.degree. C. ### Claim 4 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab is selected from the group consisting of polycarbonates, polyimides, polyetherimides, polysulfones, polyethersulfones, and reinforced polymeric materials. ### Claim 5 (depends on 4) The tape cassette of claim 4 wherein said slack limiting tab comprises a polycarbonate material or a polyetherimide material. ### Claim 6 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab comprises a polycarbonate material. ### Claim 7 (depends on 6) The tape cassette of claim 6 wherein said slack limiting tab comprises a polymeric material having a thickness of about 7.6.times.10.sup.-3 cm to 25.times.10.sup.-3 cm. ### Claim 8 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab comprises a flexible, resilient polymeric material having sufficient creep resistance to withstand storage temperatures up to at least about 60.degree. C. without the tape functionally failing and to withstand operating temperatures up to about 40.degree. C. for at least about 100 hours without the tape functionally failing. ### Claim 9 (depends on 8) The tape cassette of claim 8 wherein said slack limiting tab comprises a flexible, resilient material having a creep value of less than about 0.5% strain at 100 hours under a load of 7.0.times.10.sup.5 kg/m.sup.2 at 44.degree. C. ### Claim 10 (depends on 8) The tape cassette of claim 8 wherein said slack limiting tab comprises a polycarbonate or a polyetherimide material. ### Claim 11 (depends on 8) The tape cassette of claim 8 wherein said slack limiting tab comprises a polycarbonate material. ### Claim 12 (depends on 1) The tape cassette of claim 1 wherein said slack limiting tab comprises a contact end portion coated with an ultrahigh molecular weight polyethylene material. ### Claim 13 (depends on 12) The tape cassette of claim 12 wherein said slack limiting tab comprises a polycarbonate material having a thickness of about 7.6.times.10.sup.-3 cm to 25.times.10.sup.-3 cm.