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A wooden police baton has to be hung on the back of an officer and released only when s/he wants it to be released. I thought about "push to stow, push to release". This is a thought experiment, I am not a manufacturer...

The baton is smooth without grooves so alternative solution of releasing by rotation (like BNC plugs, or push/push pen) won't work.

Where can I find a simple design of such contraption or what terms would I use to describe this?

This is a rough model of a four bar (ABCFD) which push point E toward the object to hold (LMNOQ)

The object, represent here as rectangle LMNOQ, moves on a fixed bar (HL). When pushed up (represented by piston A1 expanding), point E moves towards the edge NQ. The angle FDB (in the locked position) is > 180 , so it should be locked, as with locking pliers.

In the open position, LMNOQ is lower, and point E is far from it. (this model is only for showing the idea. I am sure it should be modified to work in the real world)

HOW can a SECOND push unlock point D?

[partial clamping mechanism] [baton is held baton released

hazzey
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noam cohen
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  • Open up a "clicky-top" ballpoint pen for one standard example. – Carl Witthoft Dec 14 '15 at 13:14
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    I can't tell what you're trying to do here; what does "hang this stick vertically" mean? How does it constitute a "mechanical latch" per the title? Please [edit] your question to clearly describe the application. A diagram wouldn't hurt. – Air Dec 14 '15 at 17:26
  • is the stick going to support a load or just the stick itself? Can just the end of the stick have some type of engagement features? – GisMofx Dec 15 '15 at 03:24
  • the stick (baton) has to carry its own weight. It has to be smooth, so no grooves or other engagement features – noam cohen Dec 15 '15 at 10:47
  • how about you replace the "magic" with a spring and the two clamping trapezoids with urethane wheels. Put the Urethane wheels on some type of a friction inducing bearing. Now you can freely insert and remove the baton as needed as long as the friction of the wheels is correct, they won't slide out. – GisMofx Dec 15 '15 at 13:59
  • I understand how the wheels will resist pulling, but how do you release them? ( i.e. disengaging the wheels from the baton). Pushing against the spring will only tighten the hold. – noam cohen Dec 17 '15 at 22:04

2 Answers2

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From the limited information given in your question, it sounds like you might want a mechanism similar in operating principal to what is called a "push to open" drawer slide. On these drawers the draw doesn't open when you pull on it, you have to push it past a detent point and then it opens by itself basically. Hope this helps !

William Hird
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The mechanism you're looking for is named push-push latch. They are used in a lot of places and there are various patents for that. You can check this patent granted at 2005. It is for a small holder but it can be modified for bigger projects. Figure from Patent EP1596030 A2

However if I were you I'd desing a plastic holder such as the stress holder at Kinetxbatons picture given below. Moving parts and mechanisms are prone to errors and dirt is a real problem. You can check snap-fit design books I've linked in another answer.

Kinetxbatons stress holder

Community
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Gokce Mehmet AY
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  • very nice! The patent is from 2005 which is pretty amazing for me. I would expect such machines to be invented in the end of 19th century when everything was done mechanically. As for "less moving parts is better" - totally agree. – noam cohen Dec 17 '15 at 22:30
  • Patent date isn't an indication of uniqueness of solution. There might be a lot patents that resemble and solve the problem but you'll find a new aspect and get that patented. So I'm sure there were prior art. – Gokce Mehmet AY Dec 18 '15 at 11:44