NIOSHTIC-2 Publications Search

Experimental Self-Tripping Systems for Semi-Automated Metal Stamping: Design Safety, Reliability, and Quality.

Barash M; Etherton J
Sixth International System Safety Conference, September 26-30, 1983, Houston, Texas :14-5
Experimental self tripping systems for control of mechanical power presses were reviewed with respect to design safety, reliability and quality. Mechanical power presses present risk of injury to operators who have to repeatedly place their hands in the die to insert or remove workpieces. The two major problems are untimely initiation and after reach hazard. The self tripping performance relies on a photoelectronic device to automatically initiate machine action when the operator's body is a safe distance away from the machine hazard and stop machine action when the operator's body moves toward a hazard. While self tripping of mechanical presses is permitted in West Germany and Sweden, the machine performance option is restricted in the U.S., with light curtains allowed only as safety devices. A variance permitted the experimental testing of five self tripping mechanical power presses to obtain comparative safety information on self tripping versus the use of a two hand control actuator/safeguard. The self tripping method proved highly reliable, more productive and less stressful for equal amounts of work output. Integrated system and component considerations were presented, including system design, assembly and installation, maintenance inspections, light curtain reliability, the brake and clutch, press stopping time, redundant brakes or auxiliary brakes, solenoid air valve, brake monitors, control reliability and cam setting, and additional guarding.
Machine-operators; Equipment-design; Industrial-equipment; Occupational-hazards; Industrial-safety; Safety-engineering; Safety-measures; Risk-factors;
Document Type
Conference/Symposia Proceedings;
Source Name
Sixth International System Safety Conference, September 26-30, 1983, Houston, Texas
Page last reviewed: February 11, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division