Introduction: Halogen Light Changing Pole (For GU-10 and Similar Bulbs)
The light bulb changing poles you can buy at places like Home Depot or Amazon all seem to have one thing in common: they're made for larger bulbs. That leaves the rest of us out in the cold when it comes to common halogen track lights in otherwise inaccessible places. Tired of hauling out my huge, dirty ladder every time one of these burned out, I decided to make my own bulb-changing device for these bulbs out of cheap and easily-obtained parts. The entire project cost me less than $10.
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Step 1: Obtain Locking Suction Cups and PVC Fittings
There are several places you can get locking suction cups. I found these PowerLock suction cups to be the best size for this application. They are available at Home Depot or Amazon.com (and I'm sure there are other places, as well). There are various sizes, so it's best to be sure you get the right one. The bulbs I have are 50mm in diameter (roughly 2 inches), so the 2-inch suction cups worked great for me. If you get them at Home Depot, you might have to do some hunting - I found mine hanging in the nuts and bolts aisle. Often they're found in the home storage or bath sections.
The mechanism that we will create for operating the suction lock from a distance will live inside of a 1-3/4 inch slip-slip PVC coupling. Check this with your suction cup - the outer diameter of the coupling should be roughly the same as the outer diameter of the suction cup shell. Get one of those (or two, in case you make mistakes) and some pipe to go with it. The pipe will act as the extension arm, so pick whatever length you like. I found that a pre-cut 3-foot piece was plenty for me. Two of those would probably get most people the length that they want.
Step 2: Design the Locking Lever
We will be replacing the hook (which also functions as a lock) with a lever made of wood. The lever is designed to allow for a bistable mechanism, so we can pull on a string and have the suction cup go out, and pull on another one to make it go in. Whichever state it is in, it should stay there until explicitly moved.
This dictates a couple of triangles, shown in the drawing. The dimensions of the triangles are the most important measurements. A hole will be drilled precisely where the triangles touch, shown in more detail later on. The idea is that when the lever is in the position shown, the suction cup is pushed outside of its housing (4mm from axle to shell), and when it is rotated so the other arm is horizontal, the suction cup is pulled into its housing (9mm from axle to shell). If you use different suction cups, you'll need to adjust these measurements accordingly. The principle will be the same.
Step 3: Trace and Cut the Lever
I used some laminated pressboard for this. As that's about the weakest thing I could have chosen besides cardboard, you'll be pretty safe with just about any material you choose. Wood that is about 12mm thick is probably going to work great. You just have to make sure you have enough thickness to dig out a channel for the suction cup post to rotate inside the lever; I chose a thickness that was exact the same as that of the hook on the suction cups I bought (about 12mm).
I drew an accurate representation of the lever on paper using a ruler to get all of the critical dimensions right, then cut it out and traced it onto the wood. A few minutes with a pull saw and the lever was cut out.
Step 4: Drill a Hole
The hole in the lever needs to be pretty accurate. You can drill it out with a drill if you're really careful. I used a Dremel tool with a drill press accessory. For these hooks, a 1/8-inch bit worked great. Be sure to get it exactly where the triangles intersect. As the lever rotates, it will move this hole back and forth relative to the suction cup shell. When the suction cup is attached to it, it will move it in and out of its housing.
Step 5: Remove the Hook and Carve a Channel
The suction cup has a post on it that passes through the shell and attaches to the hook. In the PowerLock suction cups I used, the hook is attached to the cup by a small plastic rod that serves as an axle (the fulcrum of the locking lever). Drill this out carefully, or if you can get some leverage on it, press on one end of it with pliers until it slides out. I got leverage on mine by drilling a small hole in it and starting a screw in that end, then pressing against the screw with pliers until I could get a grip on the other side.
Once that's done, the suction cup will be free of its hook, and you can use it to ensure that the channel you're about to cut in the lever is deep enough at all of the appropriate angles. For cutting the channel, I used a Dremel tool again. You could probably do this with a tiny wood chisel, but the Dremel tool is the easiest way by far. Actually, it would be even easier if I had a MakerBot Thing-O-Matic (so I could just print this part), but we work with what we've got.
The channel is done when you can fit the suction cup post into it and keep the holes lined up while rotating the lever back and forth.
Step 6: Make an Axle, Assemble the Locking Mechanism
To make an axle for this, I cut off a nail (keeping the part with the head) and notched the not-head end, again with the Dremel tool. I placed the suction cup back into its shell, inserted the post into the channel in the lever, and slid the axle through the holes. Then I bent a piece of paper clip around the notch, holding it all in place, as depicted.
Step 7: Make a Back Support
The suction cup still moves freely when the lever is not in the locked position. This is not useful for operating it at a distance; what we need is to force it outward. This is accomplished by adding something for the lever to push against when it is in the unlocked position. The simplest way to do this is to cut a scrap of wood and screw it into the PVC coupling at just the right position. I got a little wild with this and used the lip inside of the coupling to hold everything in place without screws. The round piece of wood that I cut, along with notches for the lever arms and a lip around the circumference that rests on the PVC lip, is shown in the picture.
Again, it doesn't have to be that complicated. A wooden dowel placed perpendicular to the lever arms, and held in place with screws, would probably work just as well and be a whole lot simpler.
The picture also shows some unnecessary windows cut into the coupling - I did this so that I could see the lever action from outside, and to give the arms a little more room to swing. If you cut the arms short enough, that last part doesn't matter.
Step 8: Attach Wires to Arms
The arms will be actuated from a distance, so they'll need to be moved by wires or twine or something similar. Drill a couple of holes in each arm and make a wire loop that goes through them. I used pieces of a paper clip for my loops. I also attached wires to these, but you could easily just do this with string.
Once done, insert the assembly into the PVC coupling so that the string or wire is coming out the bottom, and the lever arms can move while the lever body pushes against the back support. If you used a dowel for that support, it would be oriented vertically in the picture shown here.
Step 9: Fasten the Shell to the Coupling
It is important that the suction cup shell be fused tightly to the PVC coupling; you'll be pressing and twisting and pulling on this interface to change bulbs, so it has to be sturdy. Glue, therefore, is not going to work. Besides, you may want to improve (or repair) it later, so glue is a bad idea in general.
The PowerLock suction cup shell has a channel running around the diameter of it. The outer ring does not contribute to suction, so we can safely drill holes through it. For this part, I placed it where I wanted it, then drilled eight holes through the shell (do not damage the suction cup itself - gently move it out of the way when doing this) and into the PVC coupling, as shown. I looped four pieces of paper clip and pushed them in, making sure that the loops were below the lip of the suction cup shell and out of the way. Do this, bend the wires down so they don't snag on anything, and you're done.
Step 10: Fasten Pipe and Change Bulbs!
Now you should have a fully-assembled mechanism. All that remains is to give it more length by slipping a piece of pipe into it. The string or wire that you attached to the lever arms should go inside of the pipe and come out the other end. Pull on one string, and the suction cup is forced outward. Pull on the other and it is forced inward. Because the lever arms don't have to move very far, and the mechanism is bistable, you can add quite a bit of length before it becomes difficult to operate the mechanism.
When changing bulbs, be careful that neither you nor anyone else is directly below the lamp - these things are heavier than they look, and rather hard. Should you lose suction while someone is standing under it, it could hurt. A lot. Not that I know from personal experience, or anything. Just be careful.
To remove a light bulb,
- Lightly moisten the cup.
- Place it into the "fully out" position using one of the strings.
- Press firmly against the face of the bulb (GU10 only! Pressing firmly on other types of bulbs could easily break them.).
- Pull the suction cup inward by using the other string.
- Rotate and pull out.
- Unlock the suction cup and twist to remove the old bulb.
To replace a light bulb,
- Again moisten the cup a little.
- Place it in the fully out position.
- Press the new bulb firmly against the suction cup.
- Lock it down.
- Use the arm to place it into the lamp, and rotate until it locks.
- Unlock the suction cup and twist to remove.
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