| 摘要 |
<p>A brake cylinder has a pair of connected pistons (12,9) of unequal size. The larger piston (12) has first (14) and second (13) chambers formed on its opposite sides. A control valve is operative in response to a reduction of brake pipe pressure to transfer air from the first chamber to a third chamber (10) formed on the side of the smaller piston (9), to move the connected pistons to a brake application position. As piston displacement occurs, pressure in the second chamber is equalised with that in the first chamber until a predetermined pressure is established in the third chamber consistent with a desired minimum brake application force. When this occurs, the control valve exhausts air from the first chamber, the volume of which is minimal in the brake application position of the larger piston.</p> |
