Technical Information Shaft Collar in Shell
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What is Nypatch®?

Bellows and Disc Couplings with Keyways

Nypatch® provides even seating of the screw, repeated screw installations and prevents galling.

Nypatch® is an anti-vibration coating applied to the threads of hardware used on clamp style rigid couplings and F-series beam couplings. It provides even seating of the screw, prevents galling, and allows for repeated screw installations to increase holding power and coupling performance. Nypatch® will also save a considerable amount of assembly time since screws do not need any additional treatments.

In the late 1970’s Ruland searched for a way to provide frictional drag on the threads of the socket head cap screws to inhibit their unintentional loosening. Many popular products were tried, but it was clear that there were no commercially available products with the necessary performance characteristics. Design considerations included a need to provide anti-vibration friction to the screw threads without absorbing excessive screw torque. Another goal was to reduce galling between the stainless steel coupling and its associated stainless steel hardware.

After considerable research, Ruland developed the Nypatch® screw thread coating. This nylon-based coating provides frictional drag to the clamping screws, keeping them from loosening and potentially fouling or flying out of the mechanism. The coating is applied in a 360-degree arc around several of the screw threads, and because it is applied to the full circumference of the threads, it will keep the screw centered in its pocket. This centering is beneficial in that it assists in the alignment of the two halves of our two-piece couplings. In addition, the circumferential coating provides the necessary dissimilar material to reduce galling on the threads of the coupling and hardware. A careful balance has been achieved providing friction, maintaining centering, minimizing galling, and allowing the screw to be loosened and re-torqued several times without degrading the overall holding ability of the Nypatch® feature.