Rollei-werke Franke & Heidecke

Erwin Scholz

Friedrich Papke

Albert Ehlers

The invention relates to a crank drive, particularly to a crank drive for photographic cameras having a crank including a crankpin, and a drawbar pivotable about the crankpin. The drawbar consists of first and second rods connected to one another, and disposed in respective substantially parallel planes, which rods are joined or connected by a hinge having a hinge axis substantially parallel to the crankpin axis.

Crank drive for a photographic camera

A focal plane shutter for a photographic camera has a brake system for braking the movement of shutter elements just before they reach their end or stop positions. At least one first brake element has a nearly constant braking torque, and at least one second brake element has a braking torque that increases over the distance of the braking movement. The constant and the increasing braking torques of the first and second braking elements are combined and applied to moving elements of the shutter, and both the constant and the increasing braking torques of the first and second brake elements are independently adjustable and settable.

Brake system for focal plane shutters of photographic cameras

A thin metallic blade or leaf of a photographic shutter, especially a shutter of the slit or focal plane type, is riveted to a trunnion which fits snugly but rotatably in an opening in a mounting plate. The trunnion has a circumferential groove intermediate its length, and the end of the trunnion remote from the shutter blade is of truncated conical shape. On the rear side of the mounting plate (the side remote from the shutter blade) there is a longitudinal groove extending tangent to the trunnion. A retaining wire in the longitudinal groove engages the circumferential groove in the trunnion, to retain the trunnion against being pulled axially out of its bearing opening in the mounting plate. In one form of the invention, the longitudinal groove for receiving the retaining wire is approximately twice the width of the retaining wire, and the wire is resilient and is held, at a distance from the trunnion, against the side of the wire groove which is toward the trunnion. The resilient wire may be sprung away from the trunnion to release the trunnion when the shutter blade is to be removed. When the shutter blade is being mounted on the plate, the frusto-conical end of the trunnion thrust the resilient wire aside and the wire snaps into the circumferential groove in the trunnion when the trunnion is fully seated in its bearing hole. In another embodiment, the groove for the retaining wire is only approximately the same width as the diameter of the wire, and the wire is moved longitudinally along its groove to engage in the circumferential groove of the trunnion or to disengage therefrom.

Mounting means for blades of photographic shutters

Timing mechanism for timing an adjustable and controlled interval between commencement of movement of two light obstructing elements of a photographic shutter, such as commencement of movement of an opening blade or curtain, and subsequent commencement of movement of a closing blade or curtain. A cam operatively connected to the first element starts to move upon the movement of that element, and controls the movement of a first pivoted lever. There is a second pivoted lever spaced from the first pivoted lever and adapted to be moved from the movement of the first lever, through an intermediate adjusting member which is moved by the movement of the first lever and which, in turn, causes movement of the second lever. For adjusting the time interval, the adjusting member is movable toward or away from the fulcrum of the first lever, and simultaneously away from or toward the fulcrum of the second lever, thereby varying the transmission ratio from one lever to the other. Predetermined movement of the second lever releases a release member, whereupon movement of the second or trailing shutter element commences. Provision is made for moving the second lever to an inoperative position, whenever it is desired to control the time interval automatically by electronic means, rather than by the mechanical lever system. The invention is particularly useful in connection with shutters of the focal plane type.

Growing community of inventors

Brunswick, Germany

Erwin Scholz