Patents Assigned to TDK Electronic Company
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Patent number: 4227622Abstract: A tape cassette comprises an upper half casing and a lower half casing and male hollow cylindrical projections having a notch mounted on either of the upper half casing or the lower half casing and female hollow recesses mounted on the other half casing at the corresponding positions. The upper and lower half casings are superposed to fit the male hollow cylindrical projects into the corresponding female hollow recesses and are fixed together by screwing self-tap bolts from the female hollow recesses into the male hollow cylindrical projections having notches to fix the projections on the inner surfaces of the female hollow recesses.Type: GrantFiled: May 23, 1979Date of Patent: October 14, 1980Assignee: TDK Electronics Company, LimitedInventors: Masatoshi Okamura, Haruo Shiba, Kimio Tanaka
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Patent number: 4222798Abstract: A method of manufacturing a ferromagnetic metal powder by continuously drying and subsequently heat treating a slurry of ferromagnetic metal powder formed by wet reduction, characterized in that a non-oxidizing gas is supplied in separate streams to the two processes, and the non-oxidizing gas used in the drying and heat treatment is treated and recovered through separate circuits for recycling to the corresponding processes of drying and heat treatment. The separate circuits for recycling the non-oxidizing gas, the conditions in the separate two circuits are made optimum and independently adjustable so that a ferromagnetic powder of good properties is obtained.Type: GrantFiled: March 13, 1979Date of Patent: September 16, 1980Assignee: TDK Electronics Company LimitedInventors: Minoru Yoda, Yasumichi Tokuoka
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Patent number: 4218722Abstract: A compact hand-held demagnetizing device is used for demagnetizing a magnetic recording and reproducing head. It comprises a handle portion and a demagnetizing head. The handle portion contains a circuit for generating a decreasing alternating current for exciting a drive coil for the demagnetizing head. Means is provided to indicate the time when the demagnetizing operation is initiated or when the demagnetizing operation can be initiated and when the demagnetizing operation is completed.Type: GrantFiled: November 1, 1978Date of Patent: August 19, 1980Assignee: TDK Electronics Company LimitedInventor: Keiichi Yoshizawa
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Patent number: 4213803Abstract: Disclosed is the addition of at least two elements of Nb, V, Ta and Zr to the ternary alloy of R (rare earth)-Co-Cu for permanent magnet materials, to thereby provide the permanent magnets with increased coercive force, residual magnetization and energy product. The additional elements enable employment of such Cu and Fe contents of the alloy as less than 10% and more than 6%, respectively. These percentages were avoided in the prior art to prevent the reduction of Br and Hc, respectively.Type: GrantFiled: February 8, 1977Date of Patent: July 22, 1980Assignee: TDK Electronics Company LimitedInventors: Tetsuhito Yoneyama, Shiro Tomizawa, Tetsuo Hori, Teruhiko Ojima
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Patent number: 4213084Abstract: A variable leakage transformer or a variable voltage transformer comprising a magnetic core with a main magnetic path and a sub-magnetic path, the main magnetic path having at least a common magnetic path with the sub-magnetic path, a primary winding wound on said common magnetic path of the core, a secondary winding wound on said main magnetic path of the core, and means for controlling the magnetic flux in said sub-magnetic path. By controlling the magnetic flux in the sub-magnetic path, the leakage of the flux induced by the primary winding from the main magnetic path to the sub-magnetic path can be controlled, thus the coupling between the primary and secondary windings, and conduction period in each cycle of the AC output voltage are controlled. The control of the conduction period in each cycle provides the control of the power transmitted from the primary winding to the secondary winding.Type: GrantFiled: March 9, 1978Date of Patent: July 15, 1980Assignee: TDK Electronics Company LimitedInventor: Hirayama Hiromitsu
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Patent number: 4212437Abstract: A tape cassette including an upper half-case and a lower half-case and a tape guide wherein the tape guide is held only on one half-case and the upper and lower half-cases are fixed by screws only from one side of the half-cases through communicating holes except for a hole for the tape guide and wherein one end of a plate spring mounted on the one half-case and the other end or middle part of the plate spring is press-contacted with a lock plate to form a cover locking mechanism.Type: GrantFiled: August 14, 1978Date of Patent: July 15, 1980Assignee: TDK Electronics Company LimitedInventors: Haruo Shiba, Masatoshi Okamura
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Patent number: 4195797Abstract: A tape cassette braking mechanism which includes a resilient plate having a flat part and two bent parts wherein the flat part is contacted with a side wall of a half-case of the tape cassette and the two bent parts are respectively contacted with corresponding brakes such that the tape is effectively held without loosing the same in the tape cassette.Type: GrantFiled: August 14, 1978Date of Patent: April 1, 1980Assignee: TDK Electronics Company, LimitedInventors: Masatoshi Okamura, Haruo Shiba
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Patent number: 4191345Abstract: A tape cassette comprises a tape guide having a cylindrical surface formed by hard chromium plating or nickel plating. The tape guide is a cylindrical plate having a slit parallel to the axis. The cylindrical tape guide has a groove at one end of the guide and is fitted to a post having a projection mounted on a half-case under connecting the groove of the guide to the projection of the post to contact the tape with the surface formed by the hard chromium plating or nickel plating.Type: GrantFiled: August 8, 1978Date of Patent: March 4, 1980Assignee: TDK Electronics Company, LimitedInventors: Takateru Sato, Shigemasa Shoji
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Patent number: 4188211Abstract: During investigation of thermal stability of the amorphous magnetic alloys by the Inventors, it was discovered that, due to the application of heat to the alloys, the hysteresis loop of the conventional, amorphous magnetic alloys was shifted in such a manner that the initial permeability of the alloys was decreased. It was also discovered that the initial permeability of the conventional amorphous magnetic alloys was irreversibly changed due to the application of heat to and the withdrawal of heat from the alloys.The present invention is characterized by the discovery of an unexpected relationship between the content of metallic elements and a metalloid element(s) of the amorphous alloy composition, thereby providing novel alloy compositions with thermally stable magnetic properties.The present invention is also characterized by incorporating an additional element or elements into an amorphous magnetic alloy, thereby providing the alloy with thermal stability.Type: GrantFiled: February 9, 1978Date of Patent: February 12, 1980Assignee: TDK Electronics Company, LimitedInventors: Norishige Yamaguchi, Kazuo Ohya, Osamu Kohmoto, Hiroki Fujishima
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Patent number: 4187998Abstract: A tape cassette comprises a locking mechanism for locking a cover for protecting a tape. The locking mechanism comprises a plate spring whose one end is fixed to a rib mounted on a half case and whose other end is pressed to a lock plate.Type: GrantFiled: July 31, 1978Date of Patent: February 12, 1980Assignee: TDK Electronics Company, LimitedInventors: Masatoshi Okamura, Haruo Shiba
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Patent number: 4181272Abstract: A tape cassette reel comprises a special clamp which is fitted to a groove of a hub. The clamp comprises an upper rib, a pair of legs extended from the upper rib; a lower rib inserted between the legs and a projected part formed on the lower rib. The projected part is fitted to a cavity formed at the bottom of the groove of the hub. A tape is completely clamped on the hub by the clamp without failure.Type: GrantFiled: July 21, 1978Date of Patent: January 1, 1980Assignee: TDK Electronics Company, LimitedInventors: Haruo Shiba, Masatoshi Okamura
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Patent number: 4169803Abstract: A piezoelectric ceramic composition which comprises the combination of a pyrochlore composite oxide and a base ceramic mixture of PbTiO.sub.3 and PbZrO.sub.3.Type: GrantFiled: September 27, 1977Date of Patent: October 2, 1979Assignee: TDK Electronic CompanyInventors: Yoichi Tanaka, Masamichi Tsuruta, Koji Takahashi, Tsutomu Hasegawa, Makoto Hori
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Patent number: 4112184Abstract: A magnetic recording medium is prepared by depositing magnetic particles of ferromagnetic, acicular iron oxide upon whose surface is adsorbed cobalt hydroxide, on a supporting substrate.Type: GrantFiled: October 7, 1976Date of Patent: September 5, 1978Assignee: TDK Electronic CompanyInventors: Shinji Umeki, Tatsuo Uebori, Minoru Motegi
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Patent number: 4087366Abstract: A piezoelectric ceramic composition which comprises the combination of a pyrochlore composite oxide and a base ceramic mixture of PbTiO.sub.3 and PbZrO.sub.3 is prepared by individually forming pyrochlore composite oxide, PbTiO.sub.3 and PbZrO.sub.3 components; and sintering a mixture of the formed components at a temperature greater than 1,000.degree. C.Type: GrantFiled: November 30, 1973Date of Patent: May 2, 1978Assignee: TDK Electronic CompanyInventors: Yoichi Tanaka, Masamichi Tsuruta, Koji Takahashi, Tsutomu Hasegawa, Makoto Hori
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Patent number: 4081114Abstract: A magnetic supporter assembly supports a mark piece in a ring permanent magnet which is magnetized to form a multipolar magnet.Type: GrantFiled: October 2, 1975Date of Patent: March 28, 1978Assignee: TDK Electronics Company, LimitedInventor: Mitio Inoue
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Patent number: 4069367Abstract: A powder magnetic material for use as a magnetic recording medium and a method of its manufacture are disclosed. More particularly, the disclosed powder magnetic material is adapted to provide a magnetic recording medium of low electric resistance. In particular, an alloy of cobalt and at least one element selected from the group consisting of vanadium, molybdenum, copper, manganese, nickel, zinc and iron is deposited onto the surface of particles of magnetic iron oxides such as Fe.sub.3 O.sub.4 or .gamma.Fe.sub.2 O.sub.3 to provide a powdered magnetic material of high coercivity, high magnetic flux density and low electric resistance.Type: GrantFiled: January 12, 1973Date of Patent: January 17, 1978Assignee: TDK Electronics Company, LimitedInventors: Shinji Umeki, Kazuhide Aue, Yasumichi Tokuoka
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Patent number: 4067755Abstract: A method of producing a powder magnetic material for use as a magnetic recording medium is disclosed. More particularly, the disclosed powder magnetic material is adapted to provide a magnetic recording medium of low electrical resistance. In particular, an alloy of cobalt and at least one element selected from the group consisting of vanadium, molybdenum, copper, maganese, nickel, zinc and iron are deposited onto the surface of particles of magnetic iron oxides such as Fe.sub.3 O.sub.4 or .gamma.Fe.sub.2 O.sub.3. Powdered magnetic material of high coercivity, high magnetic flux density and low electrical resistance is obtained.Type: GrantFiled: September 23, 1975Date of Patent: January 10, 1978Assignee: TDK Electronics Company, Ltd.Inventors: Shinji Umeki, Kazuhide Aue, Yasumichi Tokuoka
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Patent number: 4039417Abstract: A cathodic protection electrode is mounted in an iron bushing by way of a ring of alumina or forsterite, the bushing being mounted in a glass-lined metallic vessel, such as a water heater. The electrode comprises a solid solution of MFe.sub.2 O.sub.4 (wherein M is at least one metal selected from the group consisting of Mn, Ni, Co, Mg, Cu and Zn) of 0.15 to 87.1 mol%, and Fe.sub.3 O.sub.4 of 99.85 to 12.9 mol%.Type: GrantFiled: December 5, 1975Date of Patent: August 2, 1977Assignee: TDK Electronics Company, LimitedInventors: Yoshinori Sasaki, Isao Yokoyama, Motohiko Makino, Syun Awaji, Kaneo Hosoya
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Patent number: 4022716Abstract: Semiconducting ceramics are produced by firing a semiconducting composition of the barium titanate type containing vanadium oxide in the amount of 0.001 to 0.5 wt%. A change in the specific resistance over the range of the temperature at which the positive temperature coefficient characteristic of resistivity (PTCR) is exhibited can be increased by as much as 10.sup.5 times and the specific resistance value at room temperature can be controlled at a desired value. By further adding silicon dioxide to the above composition in the amount of 0.05 to 1.5 wt% the above effects can be enhanced, especially the specific resistance at ambient temperature.Type: GrantFiled: February 17, 1976Date of Patent: May 10, 1977Assignee: TDK Electronics Company, LimitedInventors: Hisayoshi Ueoka, Masatada Yodogawa
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Patent number: 4017320Abstract: A ceramic dielectric composition is provided including 30 to 94% by mol of SrTiO.sub.3, 1 to 22% by mol of Bi.sub.2 O.sub.3 and 5 to 69% by mol of TiO.sub.2, and further including 0.1 to 20% by weight of MgO with respect to the total weight of the above-mentioned three compounds SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2, whereby the ceramic dielectric composition has a high dielectric constant and a low dielectric loss and further the variations of the dielectric constant and the dielectric loss with respect to the variation of an applied voltage, are respectively, very small.Type: GrantFiled: November 19, 1975Date of Patent: April 12, 1977Assignee: TDK Electronics Company, LimitedInventors: Shinobu Fujiwara, Hitoshi Tanaka