apart, or so arranged
that the distance between the edge of the wheels and the track (K,
Fig. 1) is equal to the thickness of the tubing when pressed flat.
If the wheels fit too tightly, they will bind; it too loose, they
will let the air through. Bore a hole through the middle of the
wheel-holder and insert the crankpin, D, which should be about 1/2
in. in diameter. The crankpin should fit tightly; if necessary
drive a brad through to keep it from slipping.
In the sides (Fig. 5) bore a hole in the center of the crankpin to
run in loosely. Now put all these parts together, as shown in the
illustration. Do not fasten the sides too securely until you have
tried the device and are sure it will run smoothly. For the crank
a bent piece of stout wire or a nail will serve, though a small
iron wheel is better, as it gives steadiness to the motion. In
this case a handle must be attached to the rim of the wheel to
serve as a crank. The drive wheel from a broken-down eggbeater
will do nicely. For ease in handling the pump, a platform should
be added.
To use the pump, fill the tube with water and place the lower end
of the tube in a reservoir of water.
Pages:
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204