Abstract: The device for driving dot printing bars in a dot printer comprises at least one dot printing bar movable between two positions, an electromagnetic device controlling the operation timing of the bar, a periodically reciprocal operation member operable when the electromagnetic device is made conductive and means operable to shift the dot printing position of the bar whereby the bar springs out to effect dot printing in response to the operation of the operation member when the electromagnetic device is energized to attract the operation member thereto.

Abstract: The device for driving dot printing bars in a dot printer comprises a recording paper holding and feeding platen, dot printing bars reciprocally movable between an inoperative position and an operative position, a common rotary friction roller normally held in a predetermined spaced relationship to the bars and adapted to be engaged by the bars when the bars effect dot printing, electromagnetic devices associated with the bars to cause the bars to strike against a recording paper to effect dot printing on the paper and a control circuit operating the electromagnetic devices.

Abstract: A blade type focal plane shutter comprising a plurality of auxiliary shutter blades rotatably supported on a common shaft and movable between an unfolded position and a folded position, a main shutter blade for forming an exposure slit and a blade supporting arm serving also as a covering member so that the entire shutter may be made small and may be manufactured at a low cost.

Abstract: A timer mechanism for a clock which has a manually settable rotatable timer drum. A pair of complementarily arranged semicircular contacts which are electrically insulated from each other are adapted to actuate the timer when electrically connected to each other. Two contact fingers are provided which are urged into contact with the respective semicircular stationary contacts. A timer cam between the timer drum and a projecting lug associated with one of the contact fingers for prevention thereof from contacting one of the semicircular contacts and thereby render the timer inoperative. A flange with a cutout is provided on the timer cam which permits the one of the contact fingers to contact the semicircular stationary contact and thereby actuate the timer.

Abstract: The timer mechanism for use in a clock has a rotatable minute setting drum and a rotatable hour setting drum coaxial therewith each manually settable to a selected position to set a set time in terms of minute and hour, respectively. A first, a second and a third stationary contact member are arranged in the space between the minute and the hour setting drum for cooperating with switch contacts of first and second rotatable contact members so as to constitute together with the latter members a switch for the timer mechanism for actuating an electric device or an electrically operable warning device of the clock at a set time set by the minute and the hour setting drum.

Abstract: A film cartridge for audio-visual projectors comprising a concavity portion provided in a part of a side wall thereof and capable of cooperating with a sprocket means provided on a projector body to run the endless film in the cartridge, and a groove formed in a part of a peripheral edge thereof to contain a film loop to be formed by a loop setting means provided in the projector body, thereby to simplify the entire structure of the film cartridge.

Abstract: Indicating device comprising a plurality of overturnable indicating flaps bearing information on both sides thereof and rotatably mounted along the periphery of a rotating drum for indicating necessary information successively by one of the sides of the respective flap after the successive indication has been effected by the other side of the respective flap as the drum rotates, a guide plate having a guide hole for engaging with side edges of the respective flaps so as to guide the flaps with the same oriented in the tangential direction to the circumference of the drum as the drum rotates, a recess being formed in the circular guide hole for permitting the respective flaps to be overturned in the recess as the same is brought into the recess, and an actuating lever capable of engaging the respective flaps when brought into the recess so as to overturn the flaps within the recess.

Abstract: A memory mechanism for controlling incremental change of informations in a plurality of information systems to be indicated successively in turn.