| 摘要 |
<p>PROBLEM TO BE SOLVED: To save a space and to improve operability by arranging the fuel tank of a natural gas engine in a counterweight. SOLUTION: This counterweight 40 is made of cast iron or cast steel, and it is provided with a plurality of spaces 41 and reinforcing members 42 in it. The reinforcing members 42 are provided with a plurality of holes 42a and penetrate the spaces 41. The spaces 41 and reinforcing members 42 are arranged at such a ratio that both a function as the counterweight 40 and a function as a pressure vessel can be exerted. A chamber to be filled with a heavy object may be provided at the bottom section to reinforce the function as the counterweight 40. Since the reinforcing members 42 are provided, high pressure can be endured, therefore no gas cylinder is required to be mounted, thus the space can be effectively utilized. Natural gas has a specific gravity sufficiently smaller than that of a metal even in the compressed state to a high pressure, and no effect is given to the function of the counterweight 40 even when a small amount of gas is left.</p> |
