Brookfield, IL-In today's noise-conscious auto industry, elimination of interior squeaks, rattles, and buzzes is critical. But how do you make a hinge that's tight enough to resist a falling console lid, yet not so tight that it squeaks?

That problem faced engineers at Stocker Hinge after a major auto manufacturer expressed a need for a console lid that wouldn't slam shut. Problem was, loose console hinges were supplying no resistance, thus allowing open lids to slam shut during hard braking. Simply tightening the steel hinges wouldn't solve the problem for several reasons, the most important of which was noise. Metal-on-metal was likely to squeak.

To prevent squeaking-and still provide resistance against slamming- Stocker project engineer Donald R. Bizek designed a patented hinge that eliminates the need for metal-on-metal contact. Bizek's solution replaces the conventional steel pin with a self-lubricating nylon derivative. Key to the success of the new pin material is a combination of material characteristics. Unlike steel, the relatively compressible material possesses a "memory," exhibited in a flexural modulus of elasticity of 340,000 psi. It also features greater lubricity than either steel or pure nylon.

In the new hinge, the knuckles are wrapped more tightly around the pin than on hinges with conventional metal pins, thus eliminating the gap between the pin and knuckles. Removing the gap serves two purposes: It provides torsional resistance to the console lid's weight when it falls; and it gives the lid a more luxurious feel because it eliminates play in the hinge.

The material's compressibility and "memory" are critical to providing that torsional capacity because, together, they enable the pin to be tightly crimped without permanent deformation. As a result, a three-inch-long hinge delivers 11 lb-inches of torque--enough to slow the movement of the console door during hard braking. Tests on the unit demonstrate that it keeps its torque capacity through as many as 10,000 cycles at temperatures ranging from -20 degrees F to 160 degrees F.

"We were able to dampen the fall of the console lid, which was the customer's primary goal," notes Donald R. Bizek, project engineer for Stocker Hinge. "And at the same time, we eliminated play in the hinge and prevented it from squeaking."

The new hinge will be used in 1996 models of a prominent sport utility vehicle and a full-sized luxury sedan.

Additional details...Contact David Turner, Stocker Hinge Manufacturing Co., 8822 West 47^th St., Box 149, Brookfield, IL 60513, FAX: (708) 485-0058.