Couplings, Collars, and Clip Rings

Couplings:

These are devices used to connect two shafts or components together for power transmission.

Types of Couplings:

1. Rigid Couplings

   • Directly connect shafts in perfect alignment

   • No flexibility or movement allowed

   • Examples: Sleeve, clamp, and flange couplings

2. Flexible Couplings

   • Allow for minor misalignment

   • Can absorb vibration and shock

   • Examples: Spider, tire, and gear couplings

3. Universal Couplings

   • Allow significant angular movement

   • Common in automotive drive shafts

   • Handle larger misalignments

All circlips are similar to a “C” shape, which allows them to expand as they fit around a shaft or compress as they fit into a hole. However, the ring clip, also known as an E-ring or E-clip, more closely resembles the letter “E.” It’s one of the most widely used types of external circlips.

Standard circlips are available in internal and external versions. Internal circlips fit into the groove of a hole, whereas external circlips are designed to ensure a tight fit into a grove around the outside of a shaft or rod. They’re used to replace the need for mechanical fasteners (such as nuts, cotter pins, rivets, etc.) and typically reduce the weight of an assembly. They usually offer a longer service life.

Other benefits of using an E-clip include the fact that it can be easily pressed into a machined groove without the use of a special tool (though it can be pushed onto or off of a shaft with the support of basic pliers or a screwdriver). It also does not require a circular shaft. Generally, these devices provide a functionally that’s superior compared to the other fasteners, eliminating the need for threading, tapping, or other machining operations.

The three prongs of an E-ring make contact with the bottom of the groove, providing a shoulder for effective retention of assemblies. Unlike a snap ring, which must be slid along the axis of a shaft or rod for removal, an E-ring is easily removed from the side without any axis movement.

The typical size of an E-clip is the maximum diameter of grooves for which the clip is designed. Other important dimensions are the throat width and the free diameter. The throat width is the size of the opening and the free diameter is the outermost diameter. These are both measured accurately when the ring clip in a relaxed state.

E-clips are available in several different materials, including copper, stainless steel, carbon steel, and alloy steel, depending on the necessity of corrosion-resistance for the application. These components are widely used in machinery, from simple hand tools to complex aircraft. They’re also commonly used in transit and railway systems because they offer the advantage of easy installation and removal.

Overall, there are a variety of E-clip sizes and types depending on the application. Correct sizing is important for circlips. The component should provide a tight fit to prevent loosening. One potential disadvantage of E-clips is that it might have a limited capacity to hold a load, depending on the requirement. However, if too tight, it could also damage the shaft or affect the performance of the assembly.