Todd Graskewicz had an epiphany when he watched his mother nearly hit herself in the face with a bowling ball in 2001. Her swollen thumb had made it difficult to release the ball properly.
Graskewicz, a mold designer for Proper Mold & Engineering Inc. in Warren, Mich., decided to make an adjustable grip that could acclimate to swelling from arthritis, humidity, soreness and other factors.
He designed an outside sleeve made of nylon 6/6 with a 20-30 percent glass fill that could be superglued to the ball's thumb hole. A set of three urethane inserts adjust to the thumb's swelling. He named the product GripLoc.
``That was my first design,'' he said. ``It hit the market the very way I designed it.''
The outer sleeve was injection molded by Plastic Molded Technologies Inc. in Sterling Heights, Mich. Graskewicz and his father, Tom, who takes care of the financial aspect of their business, GripLoc Products LLC, are shopping for other custom molders.
The inner sleeves are pour-cast molded by the younger Graskewicz, who also owns Gold Crown Pro Shop in Troy, Mich.
Graskewicz has distributed GripLoc to 16 countries. Graskewicz said he has distributed 40,000-50,000 GripLocs worldwide.
There are some similar products on the market. Donkee Products of Rosemead, Calif., distributes the Sure Fit interchangeable thumb insert, and Turbo 2-N-1 Grips of Chesterfield Mich., sells the Switchgrip. Both products feature an outer sleeve and inserts made of urethane.
``Thumb inserts have been around forever,'' said Keith Kenworthy, president of Donkee. He said there are four or five that are similar to the Sure Fit. ``All we did was design one of them that can resist wear.''
Sure Fit's outer sleeve is made of plastic, but Kenworthy did not want to reveal the composition.
``I don't want someone to copy it,'' he said. ``It would be very simple to duplicate.''