Proper Training, Protective Gear, and Design Essential to Mower Safety
Appears in Print As: From the Safety Files: Poor Design Contributes to an Eye Injury
A man was mowing his lawn when the mower’s grass-collecting bag came loose. He reached down to pull it back into place, and a flying object hit him in the eye, injuring him.
The man had rented the self-propelled walk-behind unit earlier that day. A rental-center employee had shown the man how to operate the mower and attach the grass-collecting bag before loading the assembly into the renter’s car. At the mowing site, the renter mowed a few passes before he got injured.
The mower moves forward and its blade keeps spinning as a spring-loaded lever is held against the mower’s handle. During the incident, the renter continued to hold the lever down with one hand and walk behind the mower while attempting to reattach the grass-collecting bag.
A plastic frame that slides into slots on the mower’s chute holds open the inner end of the bag. A steel rod inserted into a hole in the mower body hooks into the outer corner of the bag, keeping it off the ground.
Investigators found that both the design of the grass-catching system and actions of the rental-center employee contributed to the accident.
The design made it easy to misassemble the rod and bag assembly. Friction between the rod and hole on the mower body into which it inserted was enough that a user might think he or she had correctly inserted the rod when it still had about 1.5 in. of travel before it was securely mounted. The rod would appear secure but could work itself loose under motor vibrations or travel over uneven ground.
When the rod was not properly installed, it rubbed against the mower body. A 1-in.-long strip of rust where paint had rubbed away indicated this was not the first time the rod was misinstalled.
Another set of design flaws hid critical warnings on the mower’s body from the operator. Some were obscured by the grass-collection bag, and some were molded into the grass chute in a noncontrasting color that was difficult to read.
The rental-center employee should have confirmed the renter’s understanding of the mower’s assembly and use by having him repeat these actions. The rental center should also have provided an owner’s manual and safety documentation with the mower.
Finally, because it was reasonably foreseeable that the renter would not have the right personal-protective equipment, the rental center should have provided safety glasses and hearing protection like those OSHA requires for power-mower operation in industrial settings.
Better training might have taught the renter to let go of the lever that kept the mower operating before bending down, and eye protection might have minimized his injuries.
This month’s safety violation comes from the files of Lanny Berke, a registered professional engineer and Certified Safety Professional involved in forensic engineering since 1972. Got a safety violation to share? Send your images and explanations to jessica.shapiro@penton.com.
Edited by Jessica Shapiro
© 2012 Penton Media Inc.
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Comments
Shopping Carts
I disagree about your contention that shopping carts are now wonderfully safety proofed.
I got a pretty nasty bruise on my achilles tendon by an inattentive mom and her packed full shopping cart. The bottom bar of the cart was positioned just right to hit the most vulnerable portion of my leg. How about having them move that bottom bar up a bit to hit me in the calf where the damage would heal faster? Muscle tissue heals way faster than tendons plus there's more tissue to absorb the impact.
I'd like to know what % of your time is spent designing real products vs arguing about stuff in court. What real experience do you have making real things safer? How do they sell? Are the companies you worked for prospering?
On March 6th, 2010 John (not
Unfortunately, I have not read the article on shopping cart safety, but I just experienced an injury due to a shopping cart. As with "anonymous" above, the shopping cart frame is made such that it hits the achilles tendon at its most vulnerable location. It does not matter how much "documentation" a designer has if the design still allows injuries. People pushing loaded shopping carts have no visibility as to how close they are to hitting someone's foot. That lower front part of the frame could be redesigned such that the upper part of the cart would touch someone before the lower frame. Whatever is done, a total safety review would have to be made since any change can impact other concerns. However, that lower frame needs to be rethought!
Operator incompetence
Reader James Kurk, St. Paul, Minn, writes:
"The rental-center employee should also have provided an owner’s manual and safety documentation with the mower."
Hopefully the next grocery cart I use will come with proper documentation also.
"Better training might have taught the renter to let go of the lever that kept the mower operating…."
Another classic case of trying to place blame on someone or some manufacturer for operator incompetence.
Wow… that wood chipper I am going to rent better come with full Kevlar body suit and maybe even some .pdf operating files so I can refer to them on my Blackberry during operation.
Re: operator incompetence
Lanny Berke responds:
The next time you are in the grocery store, read the warnings on the grocery cart. They are there because of accidents and serious injuries involving grocery carts. If you compare the design of the earliest grocery carts to the ones available today, you will see that the designs are very much different. The designs of today have removed pinch points and moved the center of gravity more towards the front wheels. So you see, the grocery cart DOES come with proper documentation. Most machines, equipment, and accessories rented from a rental companies are dangerous if not used properly or if the equipment is not maintained properly. In most cases, the machines and equipment are being rented by week-end warriors who only have a general idea how to use the equipment. Without proper training and/or if the equipment has not been properly maintained, the equipment could result in accidents and serious injuries. That is why OSHA requires ALL employees be properly trained in the job they are doing and the equipment that they will be using. If the wood chipper you will be using has not been properly and safely designed, if it has not been properly maintained, and/or if you have not been properly trained in its use, including reading and UNDERSTANDING the owner's manual PRIOR to using it, or any other product prior to use, your Kevlar full body protection still may not protect you.
I see that you work for St. Jude Medical. Do you think your company would condone a heart specialist using one of your products without the in-depth training that your company offers? And don't say this is a stretch. It is no more a stretch than the comparisons that you are using. Picture the heart surgeon having to refer to his or her Blackberry for step 3 of the process in the middle of an operation while installing one of your products.
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