|
|
The motor for the lift sits on the two pieces of pipe welded across the bottom of the frame.
The motor itself is a 1/50 HP 57 RPM old Bodine gearmotor, 110VDC. I had to rig up a rectifier with a couple of
resistors to convert AC to DC, but it works pretty well. The motor is fastened to the frame by two worm-gear hose
clamps.
Chains and sprockets: at first I thought I'd use the #25 roller chain. Then I found out
that the only way to take apart and reassemble industrial chains such as #25, or #40, is with a hammer etc. On the
other hand, bicycle chains have a cheapo chain tool available that easily pushes the pins out and pushes them
back in. Bicycle chain is also a lot narrower than #40 chain, which makes it esthetically more suitable.
The problem then becomes the sprocket selection. Bicycle sprockets are just not suitable for this stuff, because
they have no bore as such. Industrial chain sprockets, in addition to costing an arm and a leg, are also too wide
even though their pitch matches. For the top sprocket I got an old bicycle sprocket, cut out a disk from a 1/8"
aluminum plate, drilled the hole in the middle for the bearing, and bolted it to the sprocket with five bolts.
The trick is to center the hole exactly in the sprocket, otherwise when it turns it will pull the motor up/down
quite noticeably. For the top shaft I used 1/4" stainless steel pipe.
For the bottom sprocket that goes onto the shaft of the motor I bought a steel sprocket for a #40 chain (which
has the same pitch as bicycle chain) and got a metal shop in town to thin it down to bicycle chain width. It cost
quite a bit, both for the sprocket and for the work on it, but it was worth it to have a reliable solid sprocket
with a solid hub that will not slip or wear out.
The hook is made from two pieces of bent 12 gauge stainless steel wire welded to the chain. The top mechanism of
the lift is carefully tuned and bent to take the ball off as it comes over the top.
|
|
This spiral is pretty shallow, it is made from one piece of wire rolled into the spiral
creating a slight bank. The hard part is making sure that the ball drops into the hole
in the bottom instead of getting stuck on the track right next to the hole.
|
|
|
The cup is made out of a copper endcap that can be bought in plumbing supplies. Brazing the
steel wire to it for counterweight was pretty tricky, copper's melting temperature is a lot
less than steel's. The ball falls into the cup, tips the bridge down, and rolls out onto
the lower track. The counterweight then pulls the cup back up, where it is stopped and
positioned correctly to receive the next ball by the stop that you can see in the picture.
You can see the double turn in the picture on the right. The only trick to it is
banking the turns correctly for the ball's speed.
|
|
|
The ball rolls over the drawbridge, lowering it to go over the hole, then rolls
up an incline while the drawbridge raises again due to the counterweight, then
rolls back to fall in the hole. The drawbridge is connected to the track by welding
a couple of nuts of the right diameter to it and a couple of short pieces of wire
perpendicularly to the track, so the nuts go over the short pieces and hold the
drawbridge in place while allowing it to tip freely.
|
|
|
See the picture. The trick is positioning it correctly, which is achieved by the positioning
inverted V that is affixed below the heavy side of the teetertotter.
|
|
|
This one needs speed. The radius of the loop is fairly small, because even with the steep
drop leading to it, the speed of the ball is not that high. The loop curve has to be smooth for
this to work.
|
|
|
The spiral is the last stop before the ball pickup at the bottom. It is similar to the top spiral,
but bigger and deeper, because the speed of the ball as it comes in is higher.
|
|
|
This is where the ball sits waiting to be picked up by the hook that is attached to the lift's chain.
The spacing of the two tracks has to be tweaked to be wide enough to accommodate the hook but narrow
enough to hold the ball.
|
|
