Claims
- 1. A device for displacing movable parts of a rail switch or crossing, comprising:a plurality of hydraulic cylinder piston units arranged in offset relationship with one another in a longitudinal direction of a rail for engaging said parts, said units being hydraulically connected in series; and at least one pressure controlled directional valve connected to a duct which joins a series-connected pair of said units, said valve blocking hydraulic flow between the said series-connected pair of units if a preset differential pressure is exceeded, said differential pressure being the difference between pressure levels prevailing in oppositely arranged working volumes of one unit of the series-connected pair of units.
- 2. A device according to claim 1, comprising a plurality of said pressure controlled directional valve;, one of said pressure controlled directional valves being connected to a duct which supplies at least one of the hydraulic cylinder piston units, and an additional one of the said pressure controlled directional valves being connected to a discharge duct of said at least one hydraulic cylinder piston unit, each of said pressure controlled directional valves being powered by pressure levels prevailing in different working volumes of the hydraulic cylinder piston unit with which the respective pressure controlled directional valves are connected.
- 3. A device according to claim 1, wherein an individual pressure controlled directional valve connected to one working volume of a hydraulic cylinder piston unit is powered by the pressure level prevailing in an oppositely arranged working volume of the same unit.
- 4. A device according to any one of claims 1 to 3, wherein one of said series-connected hydraulic cylinder piston units is connected directly with a pressure controlled directional valve associated with another unit.
- 5. A device according to any one of claims 1 to 3, wherein in the event more than three hydraulic cylinder piston units are connected in series, a working volume of one unit is connected to a working volume of that unit which follows the next unit of the series, at least one pressure controlled directional valve being arranged in the connection between the working volumes so connected.
- 6. A device according to claim 5, wherein one of said series-connected hydraulic cylinder piston units is connected directly with a pressure controlled directional valve associated with another unit.
Priority Claims (1)
Number |
Date |
Country |
Kind |
603/98 |
Apr 1998 |
AT |
|
Parent Case Info
This application is the national phase of international application PCT/AT99/00087 filed Mar. 31, 1999 which designated the U.S.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/AT99/00087 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO99/51480 |
10/14/1999 |
WO |
A |
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A |
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Nov 1997 |
A |
5772157 |
Lauck et al. |
Jun 1998 |
A |
6056244 |
Durchschlag et al. |
May 2000 |
A |
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Number |
Date |
Country |
2 144 564 |
Mar 1973 |
DE |
44 20 459 |
Jan 1995 |
DE |
0 778 191 |
Jun 1997 |
EP |
WO 9634786 |
Nov 1996 |
WO |