Forensic Engineers and Consultants

Tag Archive: machine safeguarding

  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. 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…)

  3. 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…)

  4. Unguarded Shear Point on Force Tester Amputates Worker’s Finger

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    A worker was injured while testing gas springs similar to the type that hold the hatchback of an SUV open. The hazard that injured the worker was an unguarded shear point. The tester contained a mounting plate that was raised and lowered by a pneumatic cylinder.

    The pneumatic cylinder lowered the mounting plate while the worker’s fingers were in the hazardous, unguarded shear point. (more…)

  5. 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…)

  6. Case Study of an Injury Involving a Soil Mixer

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    Co-Authored with Aron Olson, P.E.

    In May, 2014, a plant farm worker was seriously injured when he fell into the hopper of an electrically powered soil mixer.  The mixer in question used a rotating steel ribbon powered by a 7-1/2 hp electric motor to mix batches of materials such as sand, mulch, wood shavings, fertilizers and other landscaping materials to create potting soil. At the top of the hopper sidewalls, within 6 inches of the ribbon, was a steel grate. (more…)

  7. A Case Study in a Coal Mine: What are a Machine Rebuilder’s Responsibilities?

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    Co-Authored with Aron Olson, P.E.

    In November of 2010, a miner was injured by a roof bolting machine (roof bolter) in an Alabama underground coal mine. The roof bolter in question had undergone a complete rebuild intended to return the machine to the original equipment manufacturer’s (OEM’s) specifications. Warren was hired to analyze both the design of the roof bolter and the actions of the rebuilder to determine if either contributed to the unfortunate coal miner’s serious injury. Background information on coal mining and roof bolters, as well as an analysis of the roof bolter and the actions of the rebuilder are included. (more…)

  8. 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…)

  9. 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…)

  10. Desk Reviews Answer Subrogation Questions

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    An important question concerning a workers’ compensation claim involving machinery and equipment is whether or not the loss can be subrogated to a responsible third party. In order to properly analyze this question, it is often helpful to have an engineer determine if the machine contains a condition of defect that caused the incident. One effective way to move ahead with confidence  — and without investing travel time and money into a full investigation — is a Warren desk review. (more…)

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