Patents by Inventor Helmut Letzel

Helmut Letzel 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: 6539760
    Abstract: A monitoring device for a protected area of a machinery installation, the area being accessible through at least one access opening which can be closed off by an element, such as a door, shutter, or the like, which is movable between an open position and a closed position. The monitoring device being arranged adjacent to the movable element and comprising a safety switch having a housing, an evaluation device, a movable element positionable between a closed and an open position, a coded release mechanism located on the movable element, and a read head for reading the coded release mechanism when the movable element is in the closed position. The safety switch being further provided with an actuator bearing a release mechanism, and which, in a locking position in the housing, locks the movable element in its closed position. The housing having a receiving space for the actuator such that the release mechanism is located adjacent to the read head when the actuator is in the locking position in the housing.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: April 1, 2003
    Assignee: K.A. Schmersal GmbH & Co.
    Inventors: Helmut Letzel, Uwe Franke
  • Patent number: 6283514
    Abstract: The invention relates to a monitoring means for an area, which can be closed off by at least one door, of a mechanical installation, comprising a safety switch which is adjacent to the respective door and can be actuated by means of an elongate, key-like actuator. It is possible for the actuator to be brought into and out of engagement with the safety switch via two actuating handles which are respectively located on the outside and inside of the door and are coupled to one another by a pin. A control means is coupled to the mechanical installation and to the at least one safety switch for releasing and blocking the at least one safety switch. In this arrangement, the actuator, which can be displaced longitudinally in a guide of a covering by actuation of one of the actuating handles, has a rack section which is in engagement with a toothed-ring segment which is coupled to the pin.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: September 4, 2001
    Assignee: K. A. Schmersal GmbH & Co.
    Inventor: Helmut Letzel
  • Patent number: 5896783
    Abstract: A safety switch device for monitoring the position of a protective cover, the cover being pivotable about an axis into and out of a closed position. The safety switch device includes a fixed position switch unit which houses at least a first electrical signal generator which will be switched between states in response to movement of the protective cover from the closed position, the signal generator being operated by an actuator which rotates about an axis. The switch device also includes a fastener element which is adjustably mountable to the protective cover and an articulated mechanical coupling which extends between the fastener element and the signal generator actuator, the coupling element being movable in at least two planes.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: April 27, 1999
    Assignee: K. A. Schmersal GmbH & Co.
    Inventor: Helmut Letzel