Abstract: The present invention relates to an audio amplifier using a pulse width modulation, and more particularly, to a pulse width modulation type audio amplifier which an average switching frequency or a cutoff frequency of a low pass filter is variable in accordance with frequency of input signal.

Abstract: An oil spatter prevention apparatus having a shaft for use with a device, such as a tape recorder, including a stationary portion fixed to a deck, a shaft body extended from the stationary portion on which a rotation body is rotatably supported on an outer circumference, and an oil spattering prevention means for preventing oil applied between the shaft body and the rotation body from being spattered when the shaft body rotates, the oil spatter prevention means being at least one of a circumferential recess on the shaft body, an annular recess on the shaft stationary portion, and a recess exterior and adjacent to the shaft.

Abstract: A tape guide device for a magnetic recording/reproducing apparatus includes a pole base assembly to guide a tape supplied from a supply reel and passed through a predetermined path to be moved horizontally to a read surface of a head drum. The pole base assembly includes a pole base installed adjacently to or separately from one side of the head drum during a loading/unloading operation of the tape. The pole base assembly also includes a pole unit including a spiral flange inclined to the pole base to be in a horizontal direction to the read surface of the head drum, to guide the tape entering the head drum to be inclined at a predetermined angle and positioned in the horizontal direction to the read surface.

Abstract: A pole base assembly driving device for a tape recorder is disclosed. Manufacturing of decks becomes simpler and at lower cost. The pole base assembly driving device has a loading gear rotatably disposed on the deck, and rotated by a driving force which is transmitted from a driving source installed on the deck. The pole base assembly further comprises an elastic rod connected by one end to the loading gear, and connected by the other end to a link member which is connected with the pole base assembly. The elastic rod is preferably made of a material which is elastically bendable by an external force, and preferably comprises a deformation restricting means for restricting a deformation of the elastic rod when the elastic rod is deformed by the rotation of the loading gear, such as protrusions on the concave side of the rod when deformed and a reinforcement member. As a result, the number of parts and manufacturing cost is reduced, and deterioration of durability due to breakage of parts can be avoided.

Abstract: A driving apparatus for loading/unloading a pair of pole-base assemblies that are reciprocated along a guide rail formed on a main deck to move a magnetic tape to contact to a head drum. The driving apparatus includes a first and a second link member, each connected with one end to each pole-base assembly, a first and a second loading gears, each connected to the other end of the first and the second link member, and being rotated in association with each other; and a main gear which is rotated by the power received from a driving motor mounted on the main deck and selectively engaged with the first loading gear upon rotation thereof. The main gear is rotated in association with one of the loading gears within a desired rotational range upon rotation thereof, so as to transfer power for loading/unloading the pole-base assembly.

Abstract: A locking device for a tape cassette housing of a tape recorder comprises a locking recess and a locking protrusion respectively provided in sides of a tape cassette housing and a deck chassis and corresponding to each other, thereby fastening a tape cassette housing to the deck chassis, the tape cassette housing resiliently coming into contact with the deck chassis as a tape cassette is loaded. In here, around external circumference of the locking protrusion is formed at least one edge, and an end of the edge comes into contact with a corner of the locking recess right before the locking protrusion is inserted into the locking recess. Accordingly, the locking protrusion comes into linear contact with the corner of the locking recess in loading/unloading operations of the tape cassette so that the stopping of the ascending and descending movements of the tape cassette housing is prevented during the loading/unloading operations of the tape cassette.

Abstract: A tape guide device for a magnetic recording/reproducing apparatus includes a pole base assembly to guide a tape supplied from a supply reel and passed through a predetermined path to be moved horizontally to a read surface of a head drum. The pole base assembly includes a pole base installed adjacently to or separately from one side of the head drum during a loading/unloading operation of the tape. The pole base assembly also includes a pole unit including a spiral flange inclined to the pole base to be in a horizontal direction to the read surface of the head drum, to guide the tape entering the head drum to be inclined at a predetermined angle and positioned in the horizontal direction to the read surface.

Abstract: Disclosed is a reel clutch of a tape recorder. A plate spring is positioned between a reel gear and a reel disc of a reel disc assembly which is mounted on a deck of a tape recorder, and a stopper reel is provided on the reel disc to restrain the engaging height of the plate spring so that a torque is generated by the frictional contact between the reel disc and the plate spring, whereby assembly productivity can be enhanced and manufacturing costs can be reduced.

Abstract: A deck mechanism for a magnetic recording/reproducing apparatus comprises a main deck provided with a head drum and a capstan motor; a sub-deck installed on the main deck to be loaded/unloaded, the sub-deck being provided with a pair of reel discs, onto which tape reels of a tape cassette are seated; a pole base loading unit for taking out and guiding a tape to be in contact with a side of the head drum when the sub-deck is loaded and guides; a pinch roller unit for compressing the tape against a spindle of the capstan motor when the sub-deck is loaded; a brake unit for selectively braking one of the roll discs; a main sliding member mounted on the main deck to be capable of reciprocatingly sliding, the main sliding member controlling the driving of the pinch roller unit; and a main cam gear mounted on the main deck to be capable of rotating, the main cam gear causing operating all of the sub-deck, the pole base loading unit, the brake unit, and the main sliding member to perform linked movements while the ma

Abstract: A power supply device of a tape-end detecting sensor for a tape recorder. The power supply device comprises a reel cover disposed on a sub-chassis, with a tape-end detecting sensor being seated on the reel cover for detecting the passing of a terminal end of a magnetic portion of a magnetic tape, a first power transmitting member mounted in the reel cover to be connected to the detecting sensor and having a first contacting portion, and a second power transmitting member disposed on the sub-chassis and having a second contacting portion that comes into contact with the first contacting portion when the reel cover is mounted on the sub-chassis. The power supply device further comprises a resilient pressing member integrally formed with the sub-chassis, for resiliently pressing the second contacting portion toward the first contacting portion to improve a contacting force between the first and the second contacting portions.

Abstract: A pinch roller unit of a magnetic recording/reading apparatus disposed on a main deck on which a head drum and a capstan are disposed to move in association with a sub-deck which is disposed to slide on the main deck. The pinch roller unit operates to bring a tape into close contact with the capstan, and comprises a pivoting lever rotatably disposed on the main deck to pivot towards the capstan in relation to movement of the sub-deck being loaded, a pinch roller rotatably disposed at an end of the pivoting lever and brought into contact with the capstan at the time of loading process, and a torsion spring stressed by being pushed by the sliding member sliding along the left and right directions of the main deck for pushing the pivoting lever towards the capstan.

Abstract: A moving deck plate for a camcorder has a sub-chassis slidably moving with respect to a main chassis. A drum base is integrally formed with the main chassis. A pair of stationary guide rails are integrally protruded from both sides of the drum base. A pair of movable guide rails provided at the sub-chassis are docked to the pair of stationary guide rails to form a moving path, along which a pair of pole bases move to draw a magnetic tape from the tape cassette. One of the stationary guide rails is coupled to the drum base by a first bridge-type reinforcing rib.

Abstract: An improved magnetic tape guiding device for use with a magnetic tape transport system of a tape recorder and the like, and a method for using the same. The magnetic tape guiding system of the tape recorder transport system has a supply reel pole base assembly having a slant pole with a first guide unit having portions formed at both ends of the slant pole to function as a conventional roller for regulating upward and downward movement of the upper and lower edges of a moving magnetic tape, and a tension pole assembly having a tension pole with a second guide unit having portions formed at both ends of the tension pole to function as a conventional impedance roller for regulating upward and downward movement of the upper and lower edges of the moving magnetic tape. This arrangement can thus achieve 2-dimensional plane-traveling of the magnetic tape while also reducing the number of the parts of the guiding system.

Abstract: A tape guide device for a magnetic recording/reproducing apparatus includes a pole base assembly to guide a tape supplied from a supply reel and passed through a predetermined path to be moved horizontally to a read surface of a head drum. The pole base assembly includes a pole base installed adjacently to or separately from one side of the head drum during a loading/unloading operation of the tape. The pole base assembly also includes a pole unit including a spiral flange inclined to the pole base to be in a horizontal direction to the read surface of the head drum, to guide the tape entering the head drum to be inclined at a predetermined angle and positioned in the horizontal direction to the read surface.

Abstract: A reel braking apparatus for a tape recorder selectively brakes a reel disk assembly, which includes a reel disk and a reel gear installed on a deck, according to an operational mode. The apparatus includes a clutch member supported by a rotation shaft installed on the deck, a gear member installed coaxially relative to the clutch member so as to rotate by being engaged with the reel gear, and a clutch spring installed between the gear member and the clutch member for restricting rotation of the gear member so that the gear member can rotate in one direction according to a rotational direction of the reel gear. The clutch member and the clutch spring are coupled to each other, and this allows the gear member installed for engagement with the reel gear of the reel disk assembly to rotate in one direction only.

Abstract: A reel braking apparatus for a tape recorder selectively brakes a reel disk assembly, which includes a reel disk and a reel gear installed on a deck, according to an operational mode. The apparatus includes a clutch member supported by a rotation shaft installed on the deck, a gear member installed coaxially relative to the clutch member so as to rotate by being engaged with the reel gear, and a clutch spring installed between the gear member and the clutch member for restricting rotation of the gear member so that the gear member can rotate in one direction according to a rotational direction of the reel gear. The clutch member and the clutch spring are coupled to each other, and this allows the gear member installed for engagement with the reel gear of the reel disk assembly to rotate in one direction only.

Abstract: The present invention relates to an audio amplifier using a pulse width modulation, and more particularly, to a pulse width modulation type audio amplifier which an average switching frequency or a cutoff frequency of a low pass filter is variable in accordance with frequency of input signal.

Abstract: A deck mechanism for a magnetic recording/reproducing apparatus and which includes a main deck where a head drum is installed, and a sub-deck which moves with respect to the main deck and where a reel table is installed. A slide member is provided between the main deck and the sub-deck and moves by a cam gear and selectively operates a pole base, brake and pinch roller.