Patents Assigned to Victor Hasselblad AB
  • Lamp changing system for projectors
    Patent number: 4142129
    Abstract: A photocell illuminated by the projection lamp of a slide projector controls a spring-biased longitudinally movable lamp exchange carrier. Lamp failure causes a change of state in the photocell that electronically releases an electromagnetic lock and allows the spring-tensioned lamp carrier to change positions. The last spare lamp is screened from the photocell, causing the electronic circuit to energize a fluorescent diode to indicate that the last spare lamp is being used.
    Type: Grant
    Filed: May 25, 1977
    Date of Patent: February 27, 1979
    Assignee: Victor Hasselblad AB
    Inventor: Anders Engstrom