Here's the solution to the mystery in my previous post.
The object you see below is a quiet carriage return wire from my purple Torpedo. It was too loose, so it wasn't working; I took it out to inspect it before squeezing it a bit tighter so it would work again.
The principle is simple: the wire is looped around the escapement wheel; when you return the carriage, the rotation of the wheel (counterclockwise in this photo) pushes the straight arm of the wire against the dog (a tooth that engages the teeth of the wheel when you're typing). This gets the dog out of the way so that the wheel's teeth don't hit it.
I don't know when the first machine with a quiet carriage return was introduced, but in the '50s this became a frequent feature on typewriters of all sizes. With me it has become a bit of a fixation. Not only does this feature make the return quieter and smoother, but it simply seems mechanically more correct: you're not wearing down the escapement or doing unnecessary work.
Usually the sound of a typewriter that lacks this feature is a not-unpleasant "zzzzzip." In fact, many typists really enjoy the canonical end-of-line sounds: click clack click clack DING zzzzzzip. But Smith-Corona portables tend to make a nasty, rasping noise when you return the carriage. It adds a jarringly unrefined element to these generally sophisticated typewriters. I've often wished I could fix it, and after studying the Torpedo wire I decided to try adapting the principle to a Smith-Corona. I set to work with some spring wire, wire cutters, and needlenose pliers.
My first prototypes were too simple. They didn't grip the escapement wheel enough, or they were liable to be knocked out of place when the typewriter was operating. So I gradually developed a more complicated shape to account for these problems.
Here's my successful design. Meet the Polt Silencer™.
Here's what it looks like when installed. (It's designed for midsized Smith-Corona portables made from 1950 on, AKA the Super 5 line and later.) Getting it in is a bit tricky, because you have to slip it under the tabulator brake (a circular device with various springs which is attached to the escapement wheel). It works just like the device on the Torpedo: when you return the carriage, the escapement wheel turns counterclockwise and the Silencer pushes the dog out of the way, avoiding That Nasty Sound.
Does it make a difference? Judge for yourself.
Without the Silencer:
With the Silencer:
(Supermodel typewriter: Sterling Silver Surfer. Video by iPad.)
It's in the nature of the Smith-Corona design that it still offers more resistance and sound than extremely smooth machines such as Olympias, but the Silencer creates a definite improvement. It leaves me wondering why the company didn't add such a feature. In any case, I feel a great satisfaction in having actually invented a helpful typewriter part.
Will the Polt Silencer ever be available to the eager masses of Smith-Corona users? Possibly. There are wonderful machines that can be programmed to make custom wire forms. It would be so much fun to watch them produce my design!