| 摘要 |
<p>1,241,365. Valves. CATERPILLAR TRACTOR CO. 25 Nov., 1969 [29 Nov., 1968], No. 57530/69. Heading F2V. A valve has a first conically shaped seat 22 located between first and second ports 14, 13, a second conically shaped seat 23 located between the second and third ports 13, 15, and a reciprocable poppet member 28 for selectively communicating the port 13 with either port 14 or 15 and comprising annular elastomeric means 31, 32 to co-operate with the first and second seats, the poppet member being rockable about an O-ring 27 on a fluid-actuated piston 26. The valve housing is formed from separate sections 16 ... 20 welded or bolted together and may be provided with a cup-shaped member or bore to act as a guide to a stem on the lower portion of the poppet. Natural rubber having a dicrometer hardness of 90 may be used for the elastomeric means which is formed with an angle a between 50 and 90 degrees and 10 degrees less than angle b. The valve is biased upwardly by a conical coil spring or by inlet pressure at port 14 and is operated by pneumatic or hydraulic pressure applied to port 24. A single member may be used in place of the separate means 31, 32 and be formed with spherical rather than conical seating surfaces.</p> |
