Industrial Machinery

"Pressure Vessel Hatch Cover Failure: A Design Analysis"
in Case Histories Involving Fatigue and Fracture Mechanics, ASTM STP 918. Philadelphia, American Society of Testing and Materials, 1985, 46-54

Ralph L. Barnett, Terrence Willis, and Mitchell Kaplan

A hatch cover on a pressurized barge exploded as a workman was kicking off one of the locking cams holding the cover to the deck. This case study reviews the factors involved in this failure, and recommends design improvements.


"Proposed National Strategy for the Prevention of Severe Occupational Traumatic Injuries"
Triodyne Safety Brief
v. 4 #4 (December 1986)

Association of Schools of Public Health

This position paper by the Association of Schools of Public Health outlines a proposal for minimizing workplace injury and advancing occupation safety.


"Stress and Strength Analysis of a Granite Press Roll"
ASME 86-WA/DE-21
. New York, Society of Mechanical Engineers, 1986

Dennis B. Brickman and George W. Pearsall

Failure of a Barre Grey granite press roll was investigated by analyzing the stresses on the roll during operation, then examining the granite by thin-section petrography and scanning electron microscopy. It appears that the failure of this roll can be explained in terms of mechanical considerations and the crystallographic structure of the material.


"Care and Feeding of PLC-Controlled Machinery"
Triodyne Safety Brief
v. 8 #3 (June 1993)

Larry K. Bell


"Care and Feeding of PLC-Controlled Machinery, Part 2"
Triodyne Safety Brief
v. 9 #4 (February 1994)

Larry K. Bell


"Care and Feeding of PLC-Controlled Machinery, Part 3"
Triodyne Safety Brief v. 10 #2 (November 1994)

Larry K. Bell

In a series of three papers the history of the mass production-long run and mass production-short run concepts in American industry is reviewed, and the operation of the tri-axis transfer machine is discussed. Part 3 also addresses product liability and guarding of the tri-axis transfer press system.


"The Grate Debate"
Triodyne Safety Bulletin
v. 4 # 2 (August 1996)

Dennis B. Brickman and Ralph L. Barnett

The full text of this paper was presented at the ASME International Mechanical Engineering Congress and Exposition in November of 1996, and is available at no cost from Triodyne Inc.


"Three Wheeled vs. Four Wheeled Turf Work Trucks"
Triodyne Safety Brief
v. 11 #4 (March 1996)

Kenneth L. d'Entremont and Ralph L. Barnett

The maneuverability, turning ability, traction performance, and lateral stability of three- and four-wheeled work trucks are evaluated.


"Foot Controls: Riding the Pedal"
Triodyne Safety Brief v. 12 # 4 (July 1997)

Ralph L. Barnett

The two predominant scenarios for accidentally tripping a foot control are stepping into the foot control and onto the pedal, i.e., "stepping contact" and keeping one foot on or just above the pedal at all times, i.e., "riding the pedal." This study shows that the various designs used to minimize "stepping contact" exacerbate inadvertent activation by "riding the pedal."


"Vehicle Lifts: The Hyperstatic Problem"
Triodyne Safety Brief v. 13 # 2 (August 1997)

Ralph L. Barnett and Peter J. Poczynok

Occasionally, vehicles topple off of structurally sound automobile lifts, even when they are properly supported at their lift points. This happens with a family of lifts that use four arms to position lifting pads under the vehicle chassis. There is a non-obvious structural phenomena called hyperstatic behavior that may easily lead to minimal, or even zero, pad loading with the attendant loss of resistance to horizontal pad movement. Unless otherwise restrained, the bumping and jostling associated with vehicle maintenance can produce random forces that will push a pad from beneath the vehicle. The resulting three-point support almost always leads to toppling of the vehicle from the lift.


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