Abstract: For reducing the number of components used and thereby attaining the reduction of cost and size while ensuring the same disk detecting performance as in the prior art, both light emitting function and light receiving function inherent in an optical pickup are utilized to constitute a disk detecting switch. Only the light emitting function of the optical pickup may be combined with a light receiving element, or only the light receiving function of the optical pickup may be combined with a light emitting element, to constitute a disk detecting switch.

Abstract: A front loading disk player has an insertion slot for receiving variable sizes of disks to be played. As the disk is inserted it encounters pinch rollers on the free ends of pivoting arms. The pressure on the pinch rollers is sensed causing the arms and their support members to move transversely of the insertion direction to open up and accommodate the diameter of the specific disk while still pinching the edge of the disk. When the disk reaches a certain stage of insertion where the central portion is past the insertion slot, the pinch rollers, arms and support members take over and pull the disk all the way into the disk player and place the disk on a turntable.

Abstract: A disc-record player comprises a deck plate (1) which carries a rotatable turntable (2) and a pivotable pick-up arm (4). This arm is rigidly connected to a pick-up arm support (24). In the turntable two depressible sensing pins (38,39) are arranged. Further, a control device is provided which comprises inter alia a drive element (20) for controlling the pivotal movement of the pick-up arm (4) and which can be coupled to the pick-up arm support (24). There is also provided a selection element (27) which can be set selectively to two operative positions and which carries first and second positioning projections (29a, 29c). The device also comprises a starting element (17). A positioning element (32) which cooperates with the selection element (27) is provided with two positioning portions (34, 35) against which the sensing pin (38, 39) abuts, after which the selection element (27) is actuated.

Abstract: A pickup arm controlling apparatus for an audio record or a video disk player, comprising an optical detecting device provided at the foremost end portion of a pickup arm for detecting a non-recorded groove portion, arranged so that a reproduction of the disk is performed by causing, due to the detecting device, the pickup arm to make a lead-in motion while the detecting action is being performed, and stopping the lead-in motion of the pickup arm upon detection of a predetermined non-recorded groove portion, and causing a stylus to descend onto the surface of the disk, wherein arrangement is provided so that, after the pickup arm has ceased its motion during the lead-in action, the pickup arm is forced to make a reversed run only for a trifle amount or distance to thereby compensate for an overshooting which could occur during the lead-in motion of the pickup arm. This trifle amount of the reversed run can be varied. Also, during a manual lead-in operation, the overshoot-compensating action is released.

Abstract: An intersong detecting circuit for an automatic music selecting device for a record player in which intersong intervals are accurately detected even for a disc having irregular reflectivities or between discs of different reflectivities. An intersong sensor detects intersong intervals between adjacent songs on a recording disc. The output signal from the intersong sensor is sampled and held at a rate determined by a leading-in time/reproducing time time-constant switching signal. The sampled-and-held signal is compared with the output of the sensor to produce a differential signal and an intersong identification signal is produced when the differential signal exceeds a predetermined threshold value.

Abstract: An automatic music selecting device in which a pickup cartridge is accurately lowered onto a disc at an intermediate position between adjacent songs on the disc even if the disc is eccentric. An intersong sensor mounted on the pickup cartridge detects the intersong intervals upon movement of the arm. The arm is stopped at a predetermined interval designated by an externally supplied song number. To do this, the output signal from the intersong sensor is held corresponding to the position just before the arm is stopped. Then, the position of the arm is finely adjusted on the basis of the difference between the level of the output signal thereafter produced by the sensor and the held level.

Abstract: Three sets of light receivers are arranged on the turn table of a phonograph record player. The light radiated on the turn table is received and introduced to light receiving elements for conversion into a pulse signal. When a 30-cm record is placed on the turn table, the three sets of light receivers are all converted and fail to produce a pluse signal. When a 25-cm record is placed on the turn table, the first set of light receivers are exposed; while when a 17-cm record is placed on the turn table, the first and second sets of light receivers are exposed. The number of pulses produced from the light receiving elements is counted, thus determining the size of the record placed on the turn table.

Abstract: A lead-in system for record players. The tone arm is mechanically moved towards a record on the record player turntable by a mechanical actuating means having a tone arm lifter. The tone arm is stopped at a position above the record lead-in groove by tone arm sensing means. Operating means are provided which can simultaneously or individually operate the tone arm lifter, the actuating means and the tone arm sensing means. The swing of the operating member of the actuating means is controlled through a positioning plate which in turn is controlled in its swing range by a selector lever of the tone arm sensing means. The operation of the operating member is thus controlled.