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Safety Eyewear

A global manufacturer of safety equipment was producing a line of molded plastic safety eyewear that specified Phillips head screws as the hinge pivots in the folding arms. Installing the screws was a tedious process, and the proper torque was critical to the proper “feel” of the hinge. If installed too tightly, the hinges were difficult to open and close. If they were too loose, the eyewear would not remain secure and comfortable on the wearer. In addition, repetitive opening and closing of the hinges resulted in the screws loosening and falling out of the assembly. In this highly competitive industry, this manufacturer needed to reduce cost and improve product quality.

SPIROL Twist-Lok™ Pins

SPIROL Model SG Semi-Automatic Dual Pin Inserter

A SPIROL Twist-Lok™ Solid, headed, helical knurled Pin was designed to be pushed into the same molded hole that accepted the screw. The helical knurl rotates as it enters the bottom hole which pulls the individual hinge components together creating the perfect “feel” and function of the assembly. This feature also allows the arms to be opened and closed indefinitely without concern of failure. Its smooth round head is visually appealing, improving the perceived quality of the product. A standard SPIROL Model SG Dual Automatic Pin Inserter is used to simultaneously install both pins into the assembly. The pins are bulk loaded into a feed bowl where they are oriented and delivered to the pinning site. The operator loads the assembly into a holding fixture, and slides it under the insertion heads. Integral activation signals the unit to install the pins and reset.

This solution increased the rate of assembly by 400%, eliminated screw walk-out, and improved the product’s appearance and function. The result is the lowest total installed cost fastening system.

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SPIROL Products in this Application Story

Solid Pins

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Pin Installation Technology

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