| 摘要 |
415,699. Hydraulic transmission of power. HYDRAULIC BRAKE CO., 84, West Hancock Avenue, Detroit, Michigan, U.S.A. Dec. 28, 1932, No. 36663. Convention date, Dec. 30, 1931. [Class 69 (ii).] The master cyclinder of a hydraulic brake or other hydraulic transmission system is provided with a rearward extension of smaller bore in which slides an extension of the piston so as to form for the cylinder a fluid seal that is under pressure during the return stroke of the piston. The master cylinder 2 has a rearward extension 16 in which slides an extension of the piston 9 which forms with the extension 16 an annular fluid-seal chamber 19 that communicates with the usual reservoir by passage 26 and pipe 6. The piston 9 is chamfered at the end to form an annular space 27 which communicates with the passage 26. Passages 28 are formed through the piston against which the cup washer 10 with axial grooves 29 is seated by the spring 21. Non-return valves 22, 23 acting in opposite directions of fluid flow serve to maintain a pressure above atmospheric normally in the pipe lines 30 and the brake cylinders connected thereto. The piston is forced inwards to apply the brakes by a pin 11 and lever 12. The return movement of the piston, effected by the spring 21, is faster than corresponds to the return of fluid through the pipe lines so that liquid flows from the rear of the piston to the forward part of the cylinder through the passages 28 and past the cupwasher 10. Further, since the bore of the extension 16 is less than that of the main part of the cylinder 2 a part of the fluid displaced by the piston 9 at the rear thereof is forced into the pipe 6 through the passages 26, 25, and since these passages are small, a pressure is created in the chamber 19 which precludes the entry of air into the system past the gasket 20. In a modification the restriction of the passage for the return of the fluid is effected by a disc valve disposed in the boss 7, which is seated by the back flow of the fluid so as to permit flow only through a small aporture in the disc. When the piston is fully returned, the port 25 is uncovered to the forward part of the cylinder 2 as shown to permit the return of the excess of fluid in the system. The pipe line 20 is shown connected to a brake actuating cylinder containing a pair of pistons engaging the shoes of an internal-expanding brake. |
