The Fall of Man

Yesterday, Levi was happily jumping in his homemade, door-frame bouncer as he does multiple times each day (see the Oct 19th post for video). He's shown an aptitude for this that Gem never quite developed.

The bouncer hangs by a rope from a screw secured into the door frame above. The rope passes slackly through an 8-inch spring allowing Levi to bounce. This is secured to a sturdy rod using an eye-hook and a bolt. Levi's fabric harness then hangs from this rod.

It all happened suddenly. Tara wasn't there at the time and all I heard was a crack, bonk, and a bang, followed quickly by a screaming infant. The following is what our forensic analysis has determined.......(grandma disclaimer....The child is fine with no lasting injuries)

The dry-wall screw we had been using for the better part of 3 years finally failed due to fatigue (many small loads over an extended period of time). It didn't actually come out of the wall but instead snapped in half (see figure below). It's assumed that the screw broke during one of Levi's "down" cycles.

At this point we now have a physical system with multiple sources of built-up potential energy. We'll start from the bottom.....

There is a 19 pound "chunk of hunk" suspended in the air with very little ability of self support. Unfortunately there is nothing but a hard tile floor waiting to receive this bundle of joy. At least he was already partially touching the ground, thereby reducing the height of his fall.

Above the child is a stout wooden rod with a few pieces of hardware protruding from various locations. This is bad enough, but unfortunately it's attached to the fully extended spring that is instantaneously recoiling. This, in effect, launches the rod and the spring downward (think of letting go of one side of a rubber band). Sadly the first part of Levi ready to catch this hurled implement is the top of his head. It's actually likely that it hit him before he hit the ground. :(

After all was calmed, kissed, fed (Dad and Levi), and analyzed we realized that it was probably not prudent to hang one of our two most important possessions from a 1/16th inch drywall screw. So to remove all doubt, I went to the hardware store and bought a 3/8th inch lag screw. A picture is provided below for comparison.