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Archive for the ‘Headlights’ Category

Headlights.

At one time a doctor would use a head mirror when examining a patient where they needed more light to see into a dark area like the throat.
Below is a photo of a head mirror.

headmirror

The early ones needed a separate powerful light source that was directed on to the mirror, the concave mirror would concentrate the light where it was needed and the doctor looked through the hole in the middle. It provided a good shadow-free light.

These were improved with a lamp that was part of the head mirror and was either battery-powered or transformed down from mains voltage. The light was directed on to the mirror.
The mirror is held in place with an adjustable headband, the mirror itself was adjusted with a ball a socket joint tightened or loosened with a wing nut. It can be flipped up and out of the way when not in use.
The mirror came with a metal cover that protected it when not in use.
The tightness of the band was adjusted either with a knob that was turned to tighten or loosen it or with a simple clip.

In terms of repairs.
1. Sometimes the headband adjusting system needed repairing, though they did not often go wrong. Difficult to say how you would repair yours because they worked in different ways, just look at it, fiddle with it and try to see how yours works and why it is not.

2. Unless you have lost the wing nut, the mirror adjustment will not go wrong.

3 It is possible that the mirror could get cracked, in that case, it might still work, you might run a little super glue along the crack to help keep it more secure. If the light quality is too poor to use it is only fit for the bin unless you have spare.
You used to be able to buy new ones but I suspect that they may no longer be available. In any case, if they are available they will not be cheap.

4. In the case of those with an attached light.
A. The batteries or bulb may need replacing.
➢ Fit new batteries and/or,
➢ Replace the bulb. (Check the contact in the bulb holder is clean and not corroded.)

Sometimes if it has not been used for some time the batteries may have become corroded, in this case, you will need to remove the batteries and clean the battery compartment contacts of any corrosion.
Do as follows.
➢ Put on a pair of rubber gloves.
➢ With a screwdriver take the batteries out and safely dispose of.
➢ Find something like an old toothbrush and some white vinegar.
➢ Give the contacts a good scrub with the brush and vinegar. Take care not to get anything in your eyes, wear a pair of glasses or goggles.
➢ Wash off the vinegar with a little water.
➢ Dry off the contacts and compartment, make sure the contacts are all clean.
➢ Fit new batteries and test.
B. The wiring may be faulty.
➢ Check with your multimeter.
C. If it is mains powered model check;
➢ The output of the transformer, if there is nothing there.
➢ The input to the transformer, if nothing there.
➢ The plug, its fuse and that the wires inside are properly connected.
➢ That there is the correct voltage coming out of the wall socket.

If there are major problems that may involve buying expensive spares my advice is to move to a more modern system. (See ‘The latest option’ below)

They moved from using a mirror on a headband to an optical fibre cable that ended at the front of the headband with a lens that directed the light where it was needed.
See below;

headlight

An example of a fibre optic cable in the photo below.

cable

The other end of the optical fibre cable was plugged into a tabletop lightbox.
This box had two powerful lamps powered from the mains, the optical fibre cable plugged into one of the lamps, the other was a reserve in case the first one failed.
They had a rheostat so you could make the light brighter or dimmer.
A switch to bring into use the spare lamp.
Inside will be a transformer and a fan to keep the lamps cool.
They will need the lamps replacing from time to time, they are specialised lamps so will not be easily available in many rural hospitals.
You might get problems with the optical fibre cable, after years of use the fibres inside will break.
To check for this, plug it into the light source and turn it on, look at the free end, do not look directly into it because it will be very bright, or turn down the brightness.
If fibres are broken you will see what looks like little black spots on the end, these black spots are individual fibres that are broken. There is nothing you can do about it.
The cable will work well with a few broken fibres but eventually so many get broken that the output is too low to be of use.
On a regular basis open up the lightbox and make sure the insides are clean and free of dust and debris and that the air input grill is clean.

The next type and probably the most often sold simply have an adjustable headlight attached to a headband. They are powered from a battery pack either with rechargeable cells or dry batteries or from the mains via a transformer.

The latest option.
All of the ones above are really expensive to buy new and to repair.
So if you need to replace one consider this……
There are lots of very high quality and bright headlamps available that are used by non-medical people for all sorts of reasons, even the most expensive and bright ones are easily affordable.
Some of them are brighter than medical ones and have a good run time, they run off dry cell batteries or a rechargeable battery.
Below is an example.

petzel

 

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