How do you wire something that opens

Question

I am trying to create a box that has a UVC light in it. I am going to have the light on the top of the box, this part will open up. The issue is the batteries and parts are at the bottom of the box with the other UVC light. So how do I wire it, because if I open the box then I have to pull on wires, and then if I close the box where will the wires go? Can anybody help me with this?

Answer 1

Normal multistrand cable tolerates well bending and torsion if the bending radius is large enough and the torsion isn't too many degrees per inch.

As suggested have hinges or other mechanical limiters which keep one edge of the roof nearly in place when the roof is opened. In that side have some binding that keeps the power cable on the surface of the wall.

More preferably you can let the cable run out of the box or behind a doubled wall. Then surely it's not in the way of the radiation and can have so much extra length that the bending stress is neglible. Having no radiation stress on the cable lets you select the mechanically best cable.

Hopefully the next image with some transparent walls can show how a cable could run freely inside a doubled wall (red) (only the problematic lamp set is drawn):

The cable will not be bent with tight bending radius, the bending distributes along the the length in the gap.

As the third principle you can put the cable have a long run near the hinge. The fasteners must be loose or preferably the run is in a tube. The motion is mostly torsional and not especially many degrees per inch.

If you are going to make a device for someone else you meet a problem. The cable must be mechanically protected and the roof movements mechanically limited so that no special carefulness is needed. The first version must have an armor around the cable. It cannot be recommended for other use than as your own custom device. The 2nd and 3rd versions are less sensitive.

Answer 2

The problem is similar to a laptop lid. There’s a couple of approaches you could use:

• flat flex cable (but watch the bend radius - it can’t be bent too much)
• braided cable has good flex capability
• round, stranded cables, routed with a ‘Z’ shape so that it twists rather than bends. This is actually the most common way for a laptop.

You could also use a pair of springs, which would double as lid closers.

Answer 3

1. Use the hinges as hinged contacts. This might work if the voltage is low, the hinges are metal and the box is insulating. Attach a wire under each half of the hinge.
2. Make a pair of curly cables that will act like springs - extending on the way out and contracting on the way in.
3. Put the wires inside a plastic tube - pneumatics tubing or fuel line - for protection so that they don't get caught as the lid closes.

Answer 4

Other answers are good, but you can do this without any wires at all coming out of the box or attaching to the lid.

Get a microswitch (or a pushbutton switch) and mount it just below the lid, so that the lid pushes on the actuator when it is in place. Use this to supply power to the lamp.

Granted, this means that closing the lid will always turn on the lamp. If this is a problem, you can do something like use an unhinged lid, that you completely remove. Cut a recess into the lid so that in one orientation the recess will be over the button, and setting the lid down will not activate the switch. Rotate the lid 180 degrees, and the lid will now activate the switch.