Abstract: The disclosed safety device electrically senses the conductivity between the electrical contacts of a camera and an accessory attached thereto, and, upon detection of a failure in conductivity, produces a warning signal for the user.

Abstract: Disclosed is a magnetically controlled focal plane shutter wherein one electromagnet controls a leading shutter curtain and another electromagnet controls a following shutter curtain by releasing respective checking members as power is supplied thereto. The electromagnetic characteristics of the electromagnet that controls the following shutter curtain differ from those of the electromagnet controlling the leading shutter curtain. According to a specific embodiment disclosed, the follower-curtain controlling electromagnet saturates earlier than the leading curtain controlling magnet so as to compensate for deterioration of an energizing battery and thereby limits the problem of shutter time lag resulting from the long battery use.

Abstract: An electromagnetically driven shutter for use in a photographic camera has blades driven by an electromagnetic drive source to move in vertical directions. The electrical power supply control means for the electromagnetic drive source is provided with means for detecting the photographic posture of the camera, whereby the output torque of the electromagnetic drive source is changed as the camera posture changes. This is done in order to insure that the speed of movement of the shutter blades is maintained constant regardless of whether or not the camera is positioned normally, or upside down.

Abstract: In a shutter of the electromagnetic release type arranged to have shutter blades locked by locking members in their charged states and to make an exposure by releasing the shutter blades from the locking members, a first locking member is arranged to lock each of the charged shutter blades while a second locking member is arranged to lock the shutter blade when the shutter blade is released from the first locking member and to have the shutter blade released therefrom by the action of an electromagnet. The releasing torque required for the second locking member is smaller than that of the first locking member.

Abstract: A hold releasing magnetic device so designed that by controlling the current supply to a magnet the armature is displaced relative to the yoke so as to release a held shutter member wherein the armature and the yoke are supported coaxially with each other on the same shaft on a base plate on which the magnetic device is mounted, with the yoke being securable on the base plate.

Abstract: In the disclosed device, an electromagnetic drive source in the form of a stator and rotor opens and closes shutter blades. A magnet sensor senses the displacement phase of the rotor, or any member operated by the rotor, to produce a timing signal at a predetermined position of the shutter during exposure. According to an embodiment of the invention, the timing signal is used for synchronizing a flash unit and the sensor is a reed switch.

Abstract: A moving coil type electromagnetic driving source designed to obtain reliable contact between slide pieces and current supply brushes for supplying current to the moving coil wherein each slide piece is provided with grooves having two inclined surfaces opposed to each other, with an elastic brush having a circular or semi-circular section being provided for each groove such that the brush is in contact with the groove at two points.

Abstract: A camera having an electromagnetic driving source for operating a focal plane shutter in the camera, includes a shutter base plate and a driving arm pivoted on the base plate for swinging movement in a plane parallel to the plate. A group of thin shutter blades are supported on the driving arm parallel to the surface of the base plate. The output shaft of a motor is coupled with the driving arm, and either one of the rotor of the motor, or a permanent magnet forming a part of the stator of the motor, provides magnetic flux parallel to the axis of the output shaft, thereby causing the rotor to rotate the output shaft and drive the focal plane shutter.

Abstract: In a slit exposure shutter having leading and trailing blades driven to run down to make an exposure and to return to their initial positions by an electromagnetic drive source, this source is provided with electromagnetically operated latch means for holding the leading and trailing blades in either one of the terminal ends of running down and returning movement thereof. Another feature is that the above-described latch means is constructed by utilizing the magnetic attraction force of at least one of the stationary and movable electromagnetic members of the drive source.

Abstract: In a slit shutter such as a focal plane shutter of the two blade type, the shutter blades and electrically operated magnetic drive means therefor are arranged on opposite sides of respective rotatable transmission means with respect to the axes thereof and are coupled therewith respectively to be movable in opposite directions relative to each other, whereby the possibility of a shock producing effect in the shutter is reduced at the time of actuation thereof.

Abstract: Disclosed is a single lens reflex camera having an electrically driven focal plane shutter. A locking arrangement locks the shutter curtains in their start positions before shutter release to prevent unintentional actuation of an exposure due to faulty operation of switches, shock, or the like. Upon completion of the upward movement of the quick return mirror, the locking mechanism is disabled.

Abstract: In the slit exposure shutter disclosed, front and rear shutter blades carry permanent magnets along a passage of electromagnets which are excited to repel the permanent magnets and cause the blades to float in the gaps of the electromagnets.

Abstract: An electromagnetically driven shutter for camera for driving the shutter blades by means of an electromagnetic driving source being characterized in that the current supply circuit to the electromagnetic driving source from the camera power source is provided with a condenser which is normally charged with the output of the camera power source or its step up circuit in such a manner that by means of the driving pulse produced with the shutter release the charge of the condenser is superposed over the power source voltage and delivered to the electromagnetic driving source so as to increase the starting speed of the shutter blades.

Abstract: An antibounce device for an electromagnetically driven shutter of a camera in which a braking current flowing in the direction reverse to the direction of a driving current is supplied to a shutter blade driving coil for a predetermined period of time immediately before completion of the travel of shutter blades.

Abstract: In the slit shutter disclosed, an actuator transmits the rotational force of an electromagnetic drive arrangement to move shutter blades through opening and closing cycles. A spring arrangement for engaging the actuating means serves to aid the shutter movement at the beginning of the cycle and retard the shutter movement at the end of each cycle while the spring arrangement is energized during its retarding action. According to an embodiment of the invention, the spring arrangement encounters an arm of the actuator at the end of each cycle, absorbs the arm movement during the retardation, and uses the energization to aid the movement at the start of the next cycle. The spring arrangement again encounters the arm at the end of the next cycle.