| 摘要 |
<p>The hydraulic chest expander consists of two cylinders (11, 14) fitted one inside the other and the outer end of each cylinder (11, 14) is attached to a handle (12, 15). The inner cylinder (11) is fitted with a piston made in two parts (6, 7) and has a piston rod (3) attached to the handle (15). The disc (6) forming part of the piston has six equally spaced holes of different sizes. The disc (7) has one hole equal in dia. to the largest of the six holes in the other disc (6). By rotating the disc (7) with respect to the disc (6) the flow of oil across the piston can be changed so that the force to expand the expander is also changed.</p> |
