Covid-19 self-retracting safety probe w/replaceable tip - *** updated ***

*** updated 4/02/20 *** - Design updated with a rear finger guard/stop, added additional internal bushings (for 4 total), updated geometry to reduce need for support & removed upper elastic band hook. (In this update the elastic band is looped above and behind the thumb slide.)
*** updated 3/31/20 *** - Design updated with dual internal bushings to help guide the shuttle, keeping the probe centered through its travel
*** updated 3/30/20 *** - Design updated with improved retention of elastic band, a more profiled and thicker thumb slide and a more pronounced locking detent
*** original design 3/28/20 ***

A simple and pocketable safety probe to provide a safe, touch-free means to operate mechanical buttons whether at the ATM, elevator, POS terminal, etc.

It possesses a few key features:

• a simple and universally replaceable probe which utilizes a standard toothpick

• has a self-retracting mechanism utilizing readily available and off-the-shelf 3/8 in (9.5 mm) diameter elastic bands (commonly used a a hair band)

• a simple locking mechanism allows it to stay extended during use. Alternatively one can use it in its "elastic range" for immediate retraction. (It locks in place only at maximum extension.)

• when retracted, the probe is safely kept inside the body of the tool. If a deeper retraction is desired, one can simply clip the length of the toothpick before first use.

• designed to be direct printed in its pre-assembled state, provided care is taken with part orientation and support.

Video demonstration here: https://www.youtube.com/watch?v=NvYNFBGi4hs

*** MISC NOTES ***

Note that this was designed to support direct printing in its pre-assembled state. In order to do that great care must be taken in the nature of the support and part orientation.

Please see the photo for details. You will see that it was printed with a generous raft, as the part is printed standing up on its very small base. Set support to "touching baseplate" and enable "tree support". This allows the support to snake into a couple of nooks and crannies in order to allow for proper support.

Studying the STL in your slicer is highly recommended before attempting to slice and print this design.

If sliced properly, cleanup is rather simple.

*** FREEING THE SLIDING MECHANISM ***

Once all support is removed it may require a bit of force to free the sliding mechanism. To free, simply invert over a solid table with the receiver hole for the toothpick downwards on the table. As printed this receiver hole stands proud of the rest of the case body.

With a firm blow from a non-marring hammer, sharply tap the case. This should shock the slider to break free from the case.

Now extend the slider all the way and place a couple of drops of a dry lube through the larger hole on top. I use a wax lube made for bicycles. Then run the slider up and down with your thumb to wear down any interfering rough surface.

*** ASSEMBLY ***

Insert toothpick with the sliding shuttle fully extended and locked. If the fit is too loose, use the woodworker's trick of soaking the toothpick in water to raise the grain. It will remain raised even after the toothpick dries.

When done stretch a 3/8 " (9.5 mm) elastic band between the bottom hook and around and behind the thumb slide for smooth operation, locking and self-retraction.