Nate Holt's Blog

February 3, 2011

Energy-absorbing mailbox 2, Snow-plows 0

Filed under: Musings — nateholt @ 2:31 pm

It is looking like my modified mailbox may survive its second year against the county snow-plows. This is a tiny bright spot in an otherwise long and bitter Ohio winter.

Here is what the mailbox across the road looks like after the latest blast of snow. Not a pretty sight.

And here is my mailbox, still standing [so far!]. The difference may be the energy-absorbing mechanism I added to the design.

The idea is that the mass of snow-plow generated ice and snow, travelling 45-55 mph and striking the mail box assembly, causes the large gray hinged part of the mailbox to swing with the blow. This does two things: 1) As the hinged mailbox part rotates, the cross-sectional area exposed to the flying wall of snow/ice is reduced (side versus back).  Some of the trailing part of the wall of snow/ice will “miss” hitting the mailbox because the box will have partially rotated out of the way – exposing the back of the box instead of its maximum broad side. 2) The movement/acceleration of  the box as it rotates on the hinges absorbs energy along with the increasing resistance provided by the stretching spring.

The net result is that the shock of a “broadside hit” is reduced and, “rolling with the punch”, the energy is dissipated over a longer period of time. The spring auto-resets the mailbox to its normal position… ready for the next snow-plow.

So far, so good…!

UPDATE: a commenter below asked whether the a violent rotation might fling out the contents of the mailbox. I made some snide comment, but this commenter has proven to be absolutely correct!  I need to adjust the door latch to be a bit stiffer…

We had another 6-inches of snow several days ago, and the mailboxes along my road were subsequently attacked by the snow-plows. Afterwards I found various pieces of my mail frozen to the road surface, extending to about 50 feet downstream from my still-standing mailbox. One key item, what was supposed to be a tax return, is pictured below, chiseled from the road’s surface ( ! )

[05-Jan-2015 Nate Holt – it’s now 2015 and the mailbox is still standing — the design seems to have worked [so far]. The winter of 2013-2014 was brutal with record snow in our state, but the snowplows were still unable to take it down. Will see what the future holds for the remainder of this winter…]

[24-Mar-2017 Nate Holt – I think we’re finished with winter of 2016-2017. The mailbox is still standing…]

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6 Comments »

  1. Not bad, how does it handle bored hooligans and baseball bats?

    Comment by Donovan — February 3, 2011 @ 5:57 pm

    • Yeah, this design doesn’t take that into account. Nor does it deal with the issue of errant vehicles or insertion of celebratory pyrotechnics ( ! )

      Comment by nateholt — February 4, 2011 @ 9:59 am

  2. Clever… but does the mail fly out as the mailbox flails?

    Comment by Jonathan — February 15, 2011 @ 10:56 am

    • Donno. Guess I’ll find out when the snow melts ( ! )

      Comment by nateholt — February 15, 2011 @ 11:05 am

  3. Came across this after my mailbox suffered a couple of severe snow plow blows and started trying to fix it. What size springs did you use? Is your mailbox still standing?

    Comment by Von — March 24, 2017 @ 9:43 am

    • Still standing! Can’t say the same for some of the other mailboxes on my road. I did replace the normal sized mailbox with next bigger size to accept larger Amazon packages. In this modification I was in a hurry and didn’t remount the springs. Now, when hit by snowplow blast, the mailbox swings 90 degrees and sticks there. But when I go out to pick up the mail, I just swing it back into position.

      Comment by nateholt — March 24, 2017 @ 8:41 pm


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