Overview

Perhaps the main, and most annoying, mistake of beginning inventors is their desire to achieve results while ignoring losses. Take for example Problem #33 the propane tank. It is not difficult to measure the weight of the leftover liquid if, from time to time, you weigh the tank. But it is a very heavy tank, so this procedure is costly and inconvenient. A good solution is to have the tank signal when only a little gas is left.

Look at the drawing. The bottom of the tank is made with a slope, and a weight is installed in it. As long as the tank has enough liquid gas in it the tank will maintain a vertical position. When the gas reaches a lower level the weight will tilt the tank and thus signal the low level of gas.

Note that this result is achieved with practically no cost. There is no need to change the gas tank. Install a wooden base with an asymmetrical weight and the regular tank will become a "talking tank."

French inventors, who first thought about this, got Patent #456403 in the Soviet Union.

Problem 65: How can We Help the Workers

Perhaps you have seen workers move a heavy railroad rail. Several people set their crowbars underneath the rail and, at a command, flip it over and over until it reaches the right position. This is hard and dangerous work. If one worker dozes, the rail could pull the bar from...