Patents by Inventor Rolf Crema

Rolf Crema has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6346981
    Abstract: A lens testing device comprises a holder, fitted on a stand, for mounting a lens specimen, a test object illuminated from the rear, an imaging objective and a detector for evaluating the image of the test object. The imaging objective can be combined with the detector to form a unit. The lens specimen is an objective specimen and the test object is arranged in the focal plane of the objective specimen inside the holder. The imaging objective is a collimator objective and the detector is arranged in the focal plane of the collimator objective. Either the holder or the unit is pivotably supported on the stand and the holder and the unit can be pivoted relative to one another.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: February 12, 2002
    Assignee: Leica Camera A.G.
    Inventors: Peter Karbe, Rolf Crema, Joachim Kühn, Bernd Harand
  • Patent number: 6318204
    Abstract: Screw mechanism having a spindle (1) which is secured in the axial direction and has a spindle axis (1′), and a spindle nut (5) which is connected to a slide (7) which can be driven and is guided in the axial direction, a joint being provided between the spindle nut (5) and the slide (7) in order to compensate for relative transverse movements and tilting between the spindle nut (5) and slide (7), said joint being formed symmetrically to the spindle axis (1′) and having two joint axes which are perpendicular to each other, intersect on the spindle axis (1′) and are assigned at one end to the transverse movement of a bearing plate (6), which is connected to the spindle nut (5), and at the other end to the transverse movement of a bearing plate (8), which is connected to the slide (7), and said joint containing an intermediate plate (9) via which the bearing plates (6, 8) are connected pivotably to each other in order to compensate for any tilting of their joint axes.
    Type: Grant
    Filed: September 27, 2000
    Date of Patent: November 20, 2001
    Assignee: Leica Camera AG
    Inventors: Gerhard Kranz, Rolf Crema, Peter Schmidt
  • Patent number: 5126881
    Abstract: A one-piece lens hood possesses a frontal surface having an approximately rectangular opening, is axially displaceable via a guide from a position of rest into a working position, and is indissolubly connected to the lens. In the position of rest, the frontal surface of the lens hood terminates flush with the front edge of an accessory mount so that the threaded portion of the accessory mount is readily accessible for screwing in accessories such as filters. A format stop is additionally provided as an integral part of the lens in order to mask out stray light. This can, for example, be formed from a blackened metal foil which is mounted on a front terminal ring of the lens.
    Type: Grant
    Filed: February 26, 1991
    Date of Patent: June 30, 1992
    Assignee: Leica Camera GmbH
    Inventor: Rolf Crema
  • Patent number: 4712897
    Abstract: The device according to the invention for adjustment of the viewfinder eyepiece of a camera incorporates a radial cam/lever mechanism which can be actuated manually. It acts on the eyepiece, which is mounted so that it can be moved in an axial direction.
    Type: Grant
    Filed: July 21, 1986
    Date of Patent: December 15, 1987
    Assignee: Ernst Leitz Wetzlar GmbH
    Inventor: Rolf Crema
  • Patent number: 4711545
    Abstract: In a film advance mechanism for perforated film, locking elements are provided to guarantee the image position for each exposure. They block the film transport sprocket against further movement after completion of each full film advance carried out via the camera winding mechanism. In addition, the mechanism releases the film transport sprocket from the blocked condition on completion of the camera shutter cycle.
    Type: Grant
    Filed: July 21, 1986
    Date of Patent: December 8, 1987
    Assignee: Ernst Leitz Wetzlar GmbH
    Inventor: Rolf Crema