Machine Design

Knife slash ends aspiring pro golfer's career

Knives are expected to be sharp and cut when used for their intended purpose.

Knives may be carried on a belt or hung on a lanyard around the neck, handle down, as during military operations, for example. In any case, a knife should stay safely sheathed until it is needed. Then it should be easily and instantly removable from the sheathe without exposing the user to harm. Unfortunately, this is not always so.

I have been an expert witness in cases where users were unaware of any dangers associated with unsheathing knives. Literature provided with the knives lacked any instructions or warnings that would teach users how to safely unsheathe the blades. In one instance, the knife purchaser attempted to remove the blade from the sheathe when it suddenly released. He severely slashed his hand, destroying any chance of him becoming a professional golfer.

Enclosed sharpeners are another source of knife accidents. Users activate such sharpeners by depressing a handle to bring the knife blade and sharpener wheels into contact. Over time, the sharpening mechanism begins to stick and lock the knife blade within. This happened to a person who subsequently tried to free the knife blade. Again, the blade suddenly released and the user was severely cut.

The manufacturers in the above cases should have done a proper hazard analysis, which would have identified hazards associated with the use of their products. Further, such hazards should have been clearly spelled out in the product literature. Neglecting to do these things is the equivalent of designing a defective product.

Lanny Berke is a registered professional engineer and Certified Safety Professional involved in forensic engineering since 1972. Got a question about safety? You can reach Lanny at [email protected]


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