Forensic Engineers and Consultants

Tag Archive: machine operation

  1. The Role of Interlocking Guards in Injury Prevention

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    In the three-part series on the CE mark, we scratched the surface of some of the requirements an equipment manufacturer must meet in order to earn this designation. Part three of the series dealt with some of the requirements for the design of a guard.  One of the items for consideration with the design of a guard is the frequency that someone will need to access the area protected by the guard.  If access is needed on a routine basis, often defined as more than once per shift, the guard needs to be designed to be movable instead of fixed.  Movable is defined as able to be opened without the use of tools.  Otherwise the frustration and time requirements of obtaining tools and removing a fixed guard will often lead to the guard being discarded. (more…)

  2. What’s Behind That CE Mark Part Three, Machine Guard Requirements

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    In the first blog in this series, we discussed the story behind the CE mark, the Machinery Directive, and the associated requirements regarding the design, production, and sale of machinery bearing the mark. The second blog discussed a cornerstone of safer machine design, the risk assessment. This installment will discuss another crucial piece of the safety puzzle, machine guard design. (more…)

  3. Load Holding Valves in Hydraulic Cranes

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    Hydraulic cranes absolutely rely on the integrity of their high-pressure fluid systems for safe operation.  A crane can become out of level when an outrigger cylinder leaks over time, possibly leading to a tip over.  A boom can collapse if a hydraulic hose ruptures.  It is not possible to absolutely prevent hydraulic cylinders from developing leaks or prevent hoses from rupturing during the life of a typical crane, therefore crane manufacturers provide load holding valves at key components to prevent these dangerous incidents.  In fact, ASME B30.5, Mobile and Locomotive Cranes, requires load holding valves or equivalent devices at outrigger cylinders, boom support cylinders, and boom telescoping cylinders. (more…)

  4. Working on the Waves While Working the Waves…

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    The rumors of my pending retirement have been greatly exaggerated…..

    Ever since I heard about The Great Loop I have wanted to cruise it (www.greatloop.org).  To successfully complete the Loop, one needs to have 3 things: adequate equipment, adequate time, and adequate health. I had the first and third.  To secure the second, I had floated the idea of a two-year sabbatical.  A year to complete any existing cases and a year to execute The Great Loop.

    With the arrival of COVID-19, our firm went to remote work. (more…)

  5. The CE Mark and What Should It Mean to You? Part Two

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    In the previous blog (Part One) we discussed the backstory behind the two stylized letters CE and what it means to the design of machinery bearing the mark.   We outlined some of the requirements of the “Machinery Directive” (MD) which include what are known as “Essential Health and Safety Requirements.” The Essential Health and Safety Requirements incorporate an iterative risk reduction process during design that takes into account (more…)

  6. Machine Guarding and Risk Assessment

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    The Occupational Health and Safety Administration (OSHA) “Top 10 for 2018” violations once again have Machine Safeguarding earning a position on the list. Machine safeguarding was the 9th most cited standard as noted in the list below:

    1. Fall protection, construction (29 CFR 1926.501)
    2. Hazard communication standard, general industry (29 CFR 1910.1200)
    3. Scaffolding, general requirements, construction (29 CFR 1926.451)
    4. Respiratory protection, general industry (29 CFR 1910.134)
    5. Control of hazardous energy (lockout/tagout), general industry (29 CFR 1910.147)
    6. Ladders, construction (29 CFR 1926.1053)]
    7. Powered industrial trucks, general industry (29 CFR 1910.178)
    8. Fall Protection–Training Requirements (29 CFR 1926.503
    9. Machinery and Machine Guarding, general requirements (29 CFR 1910.212)
    10. Eye and Face Protection (29 CFR 1926.102)

    (Source: www.osha.gov/Top_Ten_Standards.html)

    (more…)

  7. Case Study: Fatality Servicing Unsupported Excavator Boom

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    A mini-excavator at a job site developed a leak at a hydraulic fitting at the base of the cylinder that raises and lowers the boom. A subcontractor foreman at the site raised the boom to search for the leak. The foreman found and attempted to tighten the leaking fitting. When he did, the fitting separated from the base of the cylinder, releasing the hydraulic pressure that held the boom aloft. The boom fell and the bucket struck a nearby superintendent for the general contractor.

    (more…)

  8. Defective Vertical Baler Causes Serious Crush Injury to Operator’s Arm

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    I recently worked on an interesting case involving a box baler. An employee of a butcher shop put some empty cardboard boxes in a vertical box baler and pushed the control switch to compact the boxes. After the 30 by 60 inch platen weighing 851 pounds returned to its raised position, the employee reached into the open space above the bottom door on the baler and began to clear cardboard from the bale tie slots in the bottom of the raised platen. Suddenly, and without warning, the steel pin attaching the platen to the raised hydraulic cylinder rod failed. The heavy steel platen fell and crushed his arm which was outstretched over the baler door into the compaction space.

    (more…)

  9. Manufacturer Settles with Operator Injured by a Flying Tool Fragment from Milling Machine

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    In my June 2015 blog, I discussed a personal injury case where the jury decided that the lack of interlocks on the covers of a swamp cooler did not render it defective, even though it was technologically feasible to do so and their existence would have prevented the amputation.  Conversely, in another interesting personal injury case involving a computer numerically controlled (CNC) milling machine, a large settlement was made by the manufacturer with the injured operator because the machine did not have adequate interlocks on its enclosure doors. (more…)

  10. Jury Claims Swamp Cooler is Not Defective; Interlocked Guards are Not Required

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    An evaporative cooler, also known as a “swamp cooler”, is an air conditioner that works by evaporating water.   A float valve keeps several inches of water in the bottom of the unit. A pump takes water from the pan to the top of a series of vertical pads made of absorbent materials like wood fibers. The water flows by gravity through the fiber pads. A fan pulls hot air from outside the house through the soaked pads. Water in the pads evaporates, cooling the air and increasing its humidity. The cooled and humidified air is blown back into the house. Evaporative coolers need to be cleaned periodically. (more…)

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