Film changer

US4893322A · kind A · utility

Assignee

• MEDRAD, Inc. · US

Inventors

• Mark Hellmick · Calabasas, US
• Leif Johansson · Goleta, US
• Otto Weber · Wolfsburg, DE

Key dates

• Filing date: Nov 15, 1985
• Grant date: Jan 9, 1990
• Expiry date: Nov 15, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B42/045
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Disclosed is a film feeding mechanism for use during medical x-ray techniques, particularly angiography. Sheets of film are fed sequentially at high speed into and out of a film exposure device, by a feed mechanism including continuously driven feed wheels and movable pinch rollers, in a manner so as to reduce damage to the films, including the build-up and discharge of static charge on the films. In the film exposure device, a free-floating lower clamping assembly, having a natural substantially flat configuration, clamps each film against an upper clamping assembly from the center of the film progressively outward towards its leading and trailing ends, to eliminate wrinkling of the film. A firing command is transmitted to an X-ray generator before each unexposed sheet of film reaches the exposure position and each cycle of operation is accomplished by energizing a single revolution clutch connectable to a continuously running, constant speed motor.