Spiral retaining rings

Paul Boughton

Large spiral retaining rings are economically produced in stainless steel because the coiling manufacturing process produces no scrap.

The following highlights the advantages of spiral retaining rings as opposed to the standard clips ring:

* 5000 stock sizes available in carbon and stainless steel diameters from 5 mm – 2300 mm.
* 360° retaining surface. Rings have no gap and no protruding ears to interfere with assemblies.
* Spiral retaining rings available in many materials ring are avaiable from
stock in carbon or stainless steel, specials can be produced in exotic alloys and finishes.
* Uniform radial section. Provides a pleasant appearance on the assembled product. Beneficial when radial clearance is limited.
* Simplify assembly. No special pliers/tools needed to install or remove Easily wind into groove and the removal notch provided allows for easy removal using a screwdriver.
* Design flexibility. Ring thickness can be changed to accommodate any application by either varying material thickness and/or number of turns. Standard rings meet military and aerospace specifications.
* Special designs are standard. Specials produced quick and economical in many alloys. Available from 6 to 2300 mm.

Smalley Spiral Retaining Rings can be used in almost any application. There are three variables that should be considered in selecting or designing the appropriate ring: load capacity; rotational capacity; installation stress.

Understanding the load capacity of a Smalley Spiral Retaining Ring assembly requires calculations for both ring shear and groove deformation, with the design limitation being the lesser of the two.

If dynamic or eccentric loading exits, the proper safety factor should be applied and product testing conducted.

In addition, the groove geometry and edge margin (ie, the distance of the groove from the end of the shaft or housing) should be considered. When abusive operating conditions exist, true ring performance is best determined thorough actual testing.

The following outlines some applications for the rings;

* Hose fitting. To keep the cap on the fitting, a 1-Turn Retaining Ring is located in a shallow internal groove. The wall thickness of the cap is small so the ring was designed with sharp corners to operate in a very shallow groove.
* Gear assembly. External 2-Turn Retaining Ring prevents the pinion shafts from spinning when the gears are rotating. The Smalley Ring snaps securely on the groove and the rings radial wall is designed to extend radially outward, clearing the four flat pinion shaft pins by .020-in.
* Rotary Uunion The uniform cross-section of the Spiral Retaining Ring makes assembly possible in this tight radial cavity. The retaining ring is manufactured from 316 stainless steel and was an economical alternative to a circlip.
* Pulley. Two-Turn Retaining rings provide 360¢ª sidewalls as sides of the timing belt pulley. Design eliminates costly pressed-on stamped sidewalls. For belt replacement one ring can easily be removed.
* Roller bearing. Designed to flex in a shallow groove, this Spiral Retaining Ring holds the needle bearing cage assembly in the bearing housing. The previously unreliable operation of roll forming the housing was eliminated when this ring design was incorporated.
* Air vent. Single-Turn, Light-Duty Retaining Ring fits tightly in the internal groove of a plastic air vent. Ring ends are dimensioned close together, providing a complete 360¢ª-ring support surface.

Enquiry details

Smalley Europe is based in Trappes, France. www.smalley.com


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