Self-clinching retainer expands needle bearing applications

Milton Keynes, England-Special low-friction needle bearings are one of the design secrets to a new, fully automated paper folding machine from Morgana Systems. Mounted directly into the machine's sheet metal chassis, the self-aligning, self-clinching roller bearings not only eliminate the need for rigid, accurately machined mounting blocks, they allow use of less-expensive drive motors.

Able to fold as many as 18,000 sheets of paper per hour, the automated machine relies on adjustable surfaces driven by stepper motor. Space availability and cost constraints, however, require a motor with low torque output. Motor shaft support, consequently, demands needle roller bearings.

"Conventional plain bearings-the kind typically used in the past-did not prove suitable," explains Wilf Garner, Morgana's chief engineer. "Because they provide some shaft resistance to turning, plain bearings typically overloaded the new drive."

Garner says that while low-friction needle bearings worked better, the machine's thin sheet metal framework also demanded a self-aligning bearing to compensate for dynamic misalignment generated by the drive. "Self-aligning ball races were considered, but these must be pressed into a machined housing for mounting in the sheet metal framing. This additional step," he notes, "adds significant cost and creates space problems."

Solution? An easy-to-install bearing unit called ReadyMount(TM). The result of a partnership between Spyraflo Inc. and the Torrington Company, the patented design utilizes a Spyraflo full-contact, self-aligning insert to support a Torrington needle roller bearing. This assembly, in turn, is housed in a Spyraflo retainer, permitting direct installation into sheet metal as thin as 1 mm.

Requiring only a simple press operation, the installation process facilitates the cold flow of material around the retainer, ensuring a solid assembly with minimal cost. Additional benefits include quieter operation, reduced clearances, and lower operating costs as drive maintenance is reduced, or in some cases, eliminated altogether.

"Although the ReadyMount unit costs more than a standard plain bearing," Garner concludes, "overall system savings are achieved through the use of new sheet metal framework, less-expensive drive motors, and the fact that no bearing mounting block is needed."

Additional details...Contact Spyroflo, Box 2309, Peachtree City, GA 30269; Fax: (770) 487-9299; http:// www.spyraflo.com.