Despite their “non-standard” application—retaining rings are designed to snap into a simple groove on a shaft or in a bore—they are not a “specialty” fastener in the sense that they can only be used in a limited number of applications. On the contrary, you will find retaining rings just about everywhere you look from simple devices like staplers and doorknobs to more complex automotive assemblies and drones. In fact, the use of retaining rings is limited only by the designer’s imagination.
These remote-controlled devices can be used for a variety of purposes, some good, others questionable. They can travel underwater, deliver packages to your doorstep, deliver much needed blood to remote areas, and destroy pre-defined targets on a battlefield among other applications. This drone manufacturer uses retaining rings to fasten the pinion gear and shaft to the device’s propellers.
The next time you enter a room, you may indirectly be coming into contact with a retaining ring. This external retaining ring is holding the threaded portion of this doorknob in place. Notice how the lugs of the ring are reversed so as not to interfere with the threads, which must be screwed into the knob’s base. There are many variations of standard retaining rings that accommodate specific fastener requirements like this one.
That next turn you make in your car may very well depend on a retaining ring. The main body of this E-steering assembly was held in place by a bulky cover and bolts. The engineers redesigned it to eliminate these costly items and replaced it with a beveled retaining ring, another variation of a standard retaining ring. This ring features a 15-deg. angle on the outer edge and a complementary angle on the groove wall. When installed, the ring wedges itself between the groove and the retained part, eliminating endplay and vibration.
It is a great way to stay in shape. But while you are doing a hop, skip, and a jump to your favorite ditty, remember that in this model the fastener question was how to retain a bearing in the handle in the most efficient way. Engineers responded with an internal retaining ring. Machine a simple groove on the inside of the wooden handle, compress the lugs, and “snap” the ring into the groove. That is all it takes to install the ring and easily remove it when it is time to replace the bearing.
Moving parts in many devices are almost certain to feature turning gears. This photo shows gears taken from a small automobile engine. The gears are being retained on the shafts by external retaining rings.
Snail mail has certainly been on the decline, but there is still a need to send letters the old-fashioned way. Mailing machines automate this process as much as possible. The next time you watch an envelope slide through the mechanism take a look at the rollers. You will probably find they are attached to the shafts by retaining rings.
Next time you use a rechargeable screwdriver, take a look at what is holding the bearing of the rotating bit in place. There is a good chance that a retaining ring has been selected as an alternative to a shoulder or a locking ring.
Bike Brake Handle
E-bikes are gaining in popularity as more people look to go farther and faster on their bicycles. Some of the models currently on the market can reach speeds of up to 30 miles per hour. The bike brake pictured above is on an e-bike with battery indicator and power switch on the handle. A simple E retaining ring holds the pin on which the handle pivots to activate the brakes.
Chances are you will be using a weight bench on your next visit to the gym. The one pictured above features several E retaining rings holding components in place so the user can adjust the configuration to suit a particular exercise. You can see how the design engineer saved considerably on the low-cost retaining ring versus a more costly approach like threaded shafts and nuts or collars and set screws.
Here is an application that truly blurs the lines between engineering and art. Retaining rings have also been used as jewelry as shown in the accompanying photo of a bracelet, part of jeweler Wraptillion’s “Mechanical Garden” collection. The bracelet is comprised of internal and external stainless-steel retaining rings. You can check out more at www.wraptillion.com.