Seiko Koki Kabushiki Kaisha

Yukio Nakamura

Shinji Nagaoka

Shogo Kato

Kiyoshi Kitai

Hiroaki Ishida

Shougo Kato

In a self-timer starting its operation by releasing blocking of an anchor or intermediate gear blocking member, a self-timer featured in that there are provided a blocking lever which is able to move said anchor or intermediate gear to blocking position and a locking lever capable of locking said blocking lever in a releasing position, said locking lever being pushed by the intermediate gear shaft removable along a guide groove to set free the engagement of a gear train, and the blocking of the anchor or intermediate gear being so arranged as to be made by releasing locking of the blocking lever, thus enabling a driving shaft to be reset at any desired position during operation of said self-timer.

Resettable self-timer

A single-lens reflex camera shutter having an operating ring driven in one direction by a gear-rack and pinion combination. The operating ring actuates the diaphragm and shutter blades and is stopped by a stop lever during the taking of an exposure. The stop lever is locked during the taking of an exposure by a signal lever that signals the taking of an exposure and is released upon completion of an exposure to allow the operating ring to continue in its travel and carry out opening of the shutter and opening of the diaphragm blades.

Lens shutter actuating device for quick-return type single-lens reflex

A lens shutter for a quick-return single-lens reflex camera in which the diaphragm blades and shutter blades are operated by an operating ring driven rotationally in opposite directions by a driving device. The driving device has a pair of axially biased rods that coact to sequence their travel axially in two directions for driving the operating ring through gear racks on one of the rods and a driving ring coupled to the operating ring. A pinion meshes with both gear racks. A stop lever releasably locked by a signal lever stops the operating ring temporarily during taking of an exposure and the signal lever releases the stop lever at the end of an exposure which it signals or indicates. A cocking mechanism comprising a plurality of levers cocks the operating rods to cock the shutter.

Driving device of lens shutter of single-lens reflex camera

An electric shutter is opened and closed to effect an exposure in dependence upon the energization of an electromagnet. A switching circuit controls the energization of the electromagnet in accordance with various exposure information, such as diaphragm setting and film sensitivity. An exposure control circuit comprised of a series connection of a diode and a variable resistor is connected in parallel with the electromagnet and adjustably controls the time at which the electromagnet is deenergized to accordingly effect closing of the shutter such that the electromagnet delay time equals the shutter sector advancing time to thereby compensate for fluctuations between the two times.

Exposure quantity control circuit

An exposure time control circuit for an electric shutter of a camera includes a monolithic IC having input circuitry in the form of a transistorized differential amplifier having two input terminals. A time-constant circuit develops a timing signal proportional to the brightness of the object field and applies it to one input terminal and a reference voltage signal is applied to the other input terminal to control the exposure timing. In order to enable varying the reference voltage through a wide range so that the input terminals can also be used for introducing other exposure information variables, such as input signals representative of the F-value, film sensitivity, etc., a transistor is connected between the IC and the source of electric power.

Exposure time control circuit of shutter of a camera

A warning light display device for an electric shutter of a camera having an exposure time control circuit for determining the exposure time of an electric shutter in dependence upon at least the brightness of an object being photographed. A warning display circuit is connected with the exposure time control circuit and has a control transistor that receives the output of the exposure time control circuit and controls the visual indication of three stages of the warning display circuit comprising light emitting diodes that indicate adequate and inadequate exposure conditions. A reference time generating circuit is provided in the warning display circuit for developing a signal representative of a predetermined time duration and a control transistor thereof controls energization of the three stages as a function of a comparison of the exposure time duration developed by the exposure time control circuit and the predetermined time duration developed by the reference time generating circuit.

Warning display circuit of the electric shutter for camera

An exposure time control circuit for a camera shutter having a light-responsive element that controls charging of a capacitor as a function of the intensity of the light from a scene to be photographed. The charge of the capacitor at a certain level activates a switching circuit that initiates closing of the camera shutter. A light-intensity indicating circuit is directly connected to the light-responsive element for indicating the intensity of the light received from a scene to be photographed so that the camera shutter speed may be set accordingly. Photographic exposure and light readings are taken independently with control switches that need not make use of a change-over switch for connecting and disconnecting the light-intensity indicating circuit to the light-responsive element.

Growing community of inventors

Yotsukaido, Japan

Yukio Nakamura