Fig. 1
Fig. 2
Fig. 3
Automobile Tires may be Inflated Quickly by the Use of This Homemade Pump
The tee is provided with two valves, as shown in the detail sectional view, Fig. 3, the upper ball valve retaining the pressure in the pipe line, and the other valve admitting air above the piston. The ball valve has a seat of lead, and a ribbed fitting is fixed to the pipe cap above it, to provide a fastening for the hose. The cap of the other valve is fitted with a spring, adjustable on a threaded pin.
A light spring fixed to the upper side of the piston, as shown in Fig. 2, forces the piston back to its lower position after the force of the explosion in the cylinder has acted upon it. The cylinder of the pump should be oiled, and a reinforced rubber hose should be used to conduct the air under pressure to the tire.
The operation is simple: The initial stroke of the engine cylinder draws the piston down, bringing in a charge of air from the valve ports at the side of the tee; the following compression and explosion strokes drive it back, forcing the air out of the ball valve, as the other valve closes on the upstroke of the piston. A large tire may be pumped up with this device in from five to ten minutes.
Aid in Ruling Uniform Cards or Sheets
When a number of cards or sheets are to be ruled with either horizontal or vertical divisions, the following method will be found a timesaver: Rule one of the cards as a sample. Place it on the drawing board with its lower edge set against two thumb tacks driven part way in. Rule extensions of the lines on the card to a sheet of paper fastened to the board under the card. Set a third thumb tack at the right edge of the card as a guide. By placing the cards to be ruled against the three thumb tacks in the position of the original card, the rulings may be made quickly with the marks on the paper backing as guides.—W. P. Shaw, Stratford, Can.