Looking for advice: mounting mechanism

Hi folks,

For my current project I’m looking for a mounting mechanism. I’ve been thinking about a solution for quite a while now without being too happy. Perhaps some genius brain here has a perfect solution. Due to confidentiality reasons I can’t describe the project but I will try my best to explain what I’m looking for as detailed as possible.

I have a flat plastic enclosure that a user needs to attach interchangeable modules to.
In this case we assume that the module is a sturdy, 50cm diameter plastic ring. The connection between the enclosure and the module should be (ranked by priority):

-sturdy and tightly secured in all directions (The module must withstand a decent amount of pressure - e.g. a grown up man hitting the module - and not brake loose from the surface, so no loose snap-fits allowed.)

  • electricity conducting (electricity needs to flow through the enclosure into the module)
  • aesthetically seamless (the spot with the mechanism is visible, so no bulky, large adapters or release buttons sticking out. That’s why in the sketch, a silicone lid covers the mechanism when not in use.)
  • easy to attach and detach (It shouldn’t take over 5 seconds or great dexterity to attach and detach the module from the enclosure.)
  • as space efficient as possible (flat 3x6 cm mounting surface, 1cm deep inlet into the enclosure is allowed)
  • as lightweight as possible (no solid iron parts etc.).

To give you a better idea of what I’m talking about, please see the below sketch:

My solution so far is an, into the enclosure embedded,“flash shoe” that can be found on most DSLR cameras together with a “flash shoe screw” which would be the bottom part of the module (google the words to see the single components).

They apparently also come in electricity conducting versions:

I’m not 100% happy with this solution because, a conducting, metal “flash shoe screw” is probably quite expensive and heavy compared to possible plastic solutions.

Please don’t hesitate to ask any questions.
Thanks a lot in advance!

First, a “flash shoe screw” is merely a piece of bent metal. I can’t imagine a cheaper part at low volumes. And even at high volumes the fabrication can be entirely automated. Assembly costs could be prohibitive.

But for an alternative, a twist-in tab would work with your parameters. Look at how toothbrush heads twist into their electric handles. Usually a quarter turn. Look at the really cheap brushes as they mold the mechanism into the plastic so it is “free”. If you need to conduct, you can insert mold metal bits.

It’s hard if we don’t have all the details but I understand.
Also look into:
-recessed track lighting - carries current. Some you turn 90 degrees to lock into place
-80/20 inc T-slot aluminum extrusions - maybe a clever way to attach the module.

Basically longer flash shoes. But look into how they address the locking features.

also look into snowboarding, cycling and motocross equipment, bike racks, roof racks, etc.
Find something that does what you want and then work to make it smaller, then figure out the proper materials for cost and performance.

Thanks so much guys. I’ll look into your advices.

Given the size of your product (50cm), I understand lightweighting is a core aspect.
But we need more details as to load cases and contextual aspects, and your manufacturing plans.

In most cases a simple solution is best and costs aren’t very prohibitive at large numbers, as long as you minimize components and processes.
What pops into mind is a conductive ABS custom extrusion rail mounted with nylon screws and spacers on a honeycomb aluminum sandwich panel. You can also consider magnetic connections or electromagnets (some toaster trays work like that)

What’s your voltage? How many connections?

Something that I thought was pretty cool lately are the electrical connections on electric kettles. They feature 120VAC live, neutral and ground in a compact and depedanble way. They operate with gravity, but you could work out another mechanical method.