Abstract: In the disclosed focal plane shutter, desired travelling characteristics of shutter curtains are obtained by adjusting the distribution of magnetic flux density between the permanent magnet and the coil which constitute an electromagnetic drive source. Preferably, the flux density is arranged to be a maximum closer to the start position than the end position.

Abstract: A device for adjusting a focal plane shutter driving spring includes a ratchet wheel which holds one end of the shutter driving spring and is arranged to adjust the driving force of the spring by the rotation thereof. The ratchet wheel is provided with a ratchet part having fine teeth arranged to engage a ratchet pawl and a gear part having relatively coarse teeth.

Abstract: The shutter blades of a camera are made lighter in weight in order to reduce the driving power needed to obtain a desired running speed by forming the shutter blades of a metal coated plastic sheet member which may be painted black in order to prevent light reflection, with the thickness of the metal coating being between 0.001 to 0.005 mm.

Abstract: Disclosed is a focal plane shutter for a camera having a shutter blade group consisting of a plural number of light shading thin plates held with two arms, so designed that the slit forming blade positioned at the end of the arm and a light shading auxiliary blade positioned next to the above are made to move in parallel by way of a parallel linkage and that a plural number of other auxiliary blades are mounted rotatably around the shaft provided on the one arm and engaged with a common shaft provided on the other arm in such a manner that along with the rotation of the latter arm they are rotated with the latter shaft.

Abstract: A process for manufacturing blades of shutter screens wherein the blades are first formed by punching a metal plated thin plastic sheet material by a first press operation carried out thereon with end parts left connected with other portions of the plastic material. After being coated with a coating material and dried under this condition, the connecting end parts of the blades are cut off the material by a second press operation.

Abstract: In an electromagnetically driven focal plane shutter of the type having a trailing screen which moves irrespective as to whether a leading screen is moving, there are provided a detecting member arranged to detect movement of the leading screen and an inhibiting means which inhibits the trailing screen from moving when movement of the leading screen is not detected.

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: A camera shutter having a plurality of shutter blades consisting of thin plastic plates operable by means of a comparatively small driving power, so designed that in order to avoid the formation of slits at the overlapped portions of the shutter blades due to deformation magnetic powder is put in the shutter blade and magnetized along the direction of the thickness in such a manner that the blades attract each other by means of magnetic force.

Abstract: In the shutter disclosed, a conductor and a permanent magnet, movable relative to each other, form a driver to drive at least one shutter blade across an optical path for photographic light and the force of the driver is supplemented by an auxiliary spring arrangement that exerts zero force at the start of movement of the shutter blade and gradually increases toward termination of movement of the blade.

Abstract: A focal plane shutter device of the present invention is provided with leading blade braking means arranged near the terminal end of running down movement of the leading blades of the focal plane shutter to stop said leading blades in a standstill position either directly or through a member cooperative with the leading blades, and brake releasing means arranged in the trailing blades of the shutter upon termination of running down movement of the trailing blades to release the above-described leading blade braking means. Another feature is that the member cooperative with the leading blades in the standstill position and the braking member form a synchro-contact for use in flash photography.