Hydraulic elevator and hydraulic control valve for a hydraulic elevator

Abstract

The invention relates to a hydraulic elevator with an elevator car, which can be moved vertically in an elevator shaft and with a hydraulic control valve (10) by means of which the lowering of the elevator car can be controlled. The hydraulic control valve (10) has a down piston, by means of which a hydraulic control line from the elevator car to a storage tank can be opened or closed. The position of the down piston can be controlled by a D-solenoid (20), by means of which a hydraulic line from the down piston pilot chamber to the tank can be opened or closed. According to the invention there is a second solenoid (42) positioned in the hydraulic line from the down piston pilot chamber to the tank, the second solenoid (42) being positioned between the D-solenoid (20) and the tank.

Description

TECHINCAL FIELD

[0001] The invention relates to an elevator system. An elevator system is a system by means of which persons or loads in a movable car or cabin, in a carriage or on a platform can be transported in a vertical or slanted direction between two or more levels. Usually, there are predetermined access points provided at which the cabin can be entered or exited.PRIOR ART

[0002] In practice, passenger and goods & passenger elevators are designed in particular as cable car elevators (drum lift or drive pulley lift) and as hydraulic elevators.

[0003] In the drum lift, two opposite drums are mounted on one axis. A support cable is fixed to each drum, which can be wound onto the drum and be unwound from it. At the free end of one support cable, the car is fixed while at the free end of the other support cable a counterweight is fixed. Since the length of the support cables is limited by the size of the drum, the drum lift is generally not suitable for large conveying heights.

[0004] In the drive pulley lift, the car is attached to one end of the support cable and the counterweight to the other end of the support cable. The support cable is guided via a driven roller. The support cable is not attached to this roller, but is held and moved by friction. The length of the support cable can be varied as desired, making this type of elevator system suitable for high-rise buildings. The engine room is usually located above the elevator shaft.

[0005] In hydraulic elevators, the car is moved by one or more hydraulic pistons. These are usually installed vertically at the bottom of the elevator shaft. Hydraulic elevators are more suitable for smaller lift heights up to about 18 to 25 meters.

[0006] Elevator systems are systems requiring monitoring within the meaning of the Operational Safety Regulations. Therefore, elevator systems must be inspected by an approved inspection facility every year at the latest. Elevators are usually equipped with a safety system that can prevent deviations from normal operation even if all the supporting cables (in the case of cable car elevators) should break. In hydraulic elevators, a pipe rupture protection is installed directly at the connection of the cylinder. This stops the elevator car automatically in case of excessive speed or pipe rupture.

[0007] All in all, elevator systems are one of the safest ways for transporting goods and passengers. One of the greatest risks of injury is if the car starts to move while the doors of the car are open. In this case, passengers may be injured. For this reason, there must be a redundant safety system that can prevent the car from moving when the doors are open. In hydraulic elevators, this is realized in the downward direction by an additional intermediate valve. This intermediate valve is arranged between the valve block and the hydraulic system. The intermediate valve is attached to the actual valve block and to the rest of the hydraulic system by means of hydraulic connectors.

[0008] According to the European Patent Application EP 3 444 213 A1 the hydraulic control valve has a first and a second piston rod, both of which extend through a central hydraulic chamber. The position of the first piston rod is controlled by a first valve unit and the position of the second piston rod is controlled by a second valve unit. The first and the second valve units are arranged in a common valve unit. The central control piston can be held together in its CLOSED-position by the pressure in the central hydraulic chamber as well as by the second piston rod. However, for safety reasons, the second piston rod or the pressure in the central hydraulic chamber is sufficient to fix the central control piston in this CLOSED-position. The transfer of the central control piston into its OPEN-position, on the other hand, is only possible by a cooperation of both measures.

[0009] Existing EN81-20 / 50 standard requires double safety against unintended car movement when the elevator is at the floor and the doors are open. In up direction, the double safety can be assured by employing double contactors in series. Similarly, to satisfy the standard in down direction an additional check valve is normally used at the exit of the cylinder line. In that configuration there are two check valves in series that are operated by solenoids. Those solenoids are normally close solenoids. Unless both solenoid coils of the check valves are energized, the down movement is prevented. In this way, unintended car movement (UCM) is prevented and a higher safety level is obtained.

[0010] Usually, the hydraulic control valve has a build-in down piston, by means of which a hydraulic control line from the elevator car (hydraulic cylinder) to a storage tank can be opened or closed. The down piston is kept closed by the oil pressure coming from the hydraulic control line. The position of the down piston can be controlled by a first solenoid, by means of which a hydraulic line from the down piston pilot chamber (D Chamber) to the tank can be opened or closed. When the first solenoid is energized, oil in the down piston chamber flows into the tank so that the pressure in the down piston pilot chamber drops and the down piston opens. This allows oil from the elevator car (hydraulic cylinder) to flow into the tank. Thus, the elevator car starts a down travel.

[0011] In present applications, an external check valve can be added into the hydraulic control line at the cylinder port. This external check valve can have a check piston operated by a check solenoid. This check valve is designed so that it opens in up direction travel without needing to energize the check solenoid. However, in down direction, the check solenoid has to be energized in order to have a down travel. The check piston works with the same principle than the build-in down piston. If the check solenoid is energized, the down travel can start provided that the first solenoid is also energized. If only the check solenoid or the first solenoid is energized, no down travel is possible.

[0012] As both the control valve and the check valve are positioned in the hydraulic control line, this generates pressure losses due to the additional housing cavities and connectors. Therefore, more energy is spent and the minimum allowable working pressure of the control valve increases. Those energy losses are converted into heat and increase the oil temperature. The end effects are the drop of performance of the control valve due to changes in oil viscosity, the increased risk for external leakage and the enlarged dimensions of the hydraulic control valve.SUMMARY OF THE INVENTION

[0013] Starting from this prior art, the object of the invention is to provide an improved hydraulic elevator with a redundant safety system, in which the safety system can be mounted and maintained as compactly and economically as possible and has nor pressure loss.

[0014] The hydraulic elevator according to the invention is provided by the features of the main claim 1. The hydraulic control valve according to the invention is provided by the features of claim 6. Meaningful developments of the invention are the subject of further claims following these claims.

[0015] The hydraulic elevator according to the invention comprises an elevator car, which can be moved vertically in an elevator shaft, and a hydraulic control valve by means of which the lowering of the elevator car can be controlled. The hydraulic control valve has a down piston, by means of which a hydraulic control line from the elevator car to a storage tank can be opened or closed. The position of the down piston can be controlled by a D-solenoid, by means of which a hydraulic line from the down piston pilot chamber to the tank can be opened or closed. According to the invention, there is a second solenoid positioned in the hydraulic line from the down piston pilot chamber to the tank, this second solenoid being positioned between the D-solenoid and the tank.

[0016] By doing that, the second solenoid is removed from the hydraulic control line. This is advantageous in regard to pressure losses. Furthermore, extra oil in the down piston pilot chamber can be supplied via the second solenoid in the case of unintended car movement. The down piston can therefore be closed rapidly which is a crucial for safety measurements.

[0017] Usually it is sufficient to have the D-solenoid configured as an on-off-solenoid.

[0018] According to a first embodiment of the invention, the second solenoid can be configured as an on-off-solenoid. There are many elevator applications that do not need to satisfy USM safety in a very large pressure and flow ranges. In these cases, it is sufficient to use an on-off-solenoid as the second solenoid.

[0019] According to a second embodiment of the invention, the second solenoid can be configured as a double-acting solenoid. In this case, the second solenoid can be further positioned between the hydraulic control line and the down piston pilot chamber.

[0020] Preferably, both the D-solenoid and the second solenoid can be positioned in the hydraulic line from the down piston pilot chamber to the tank. Only the second solenoid can also be positioned in a second hydraulic line connecting to a hydraulic line between the hydraulic control line and the down piston pilot chamber.

[0021] The hydraulic control valve for a hydraulic elevator comprises a housing and a hydraulic control line. Furthermore, there is a down piston being positioned in the hydraulic control line. Starting at the down piston pilot chamber there is a hydraulic line ending at a connection element in the housing. The hydraulic control valve further comprises a D-solenoid, by means of which the hydraulic line from the down piston pilot chamber to the connection element can be opened or closed, thereby controlling the position of the down piston. This kind of hydraulic control valves are already known in the state of the art and can be purchased in different versions. According to the invention, there is a check valve element present which is configured as a separate component and which can be fastened to the housing of the hydraulic control valve via the connection element. The check valve element comprises a hydraulic line between the connection element of the housing and an output connection and a second solenoid being positioned in this hydraulic line.

[0022] Therefore, the hydraulic control valve according to the invention can also be used in modernization projects. There are about five times more modernization projects available in the lift market than for new lifts. Moreover, all modernizations should comply with the new standard, that is EN81-20 / 50. Therefore, it is important to provide a solution that can be simply applicable to the existing elevator control valves. The invention provides such a plug & play solution both for new and existing hydraulic control valves.

[0023] The check valve element can be fixed to the housing of the hydraulic control valve with at least one connection element. This at least one connection element was designed to satisfy UCM functionality. In that way, the check valve element can be used for new hydraulic control valves as well as for modernization of existing hydraulic control valves. Furthermore, since the check valve element is not placed in the hydraulic control line, pressure losses both in up and in down directions will be eliminated and a very compact solution for new and existing installations can be presented.

[0024] The check valve element can comprise an adjustment element, by means of which the check valve element can be fastened to the connection element of the housing of the control valve. In this case, the hydraulic line of the check valve element leads through the adjustment element. The adjustment element can also serve as output connection, thereby enabling a simply way of connecting the check valve element to a hydraulic line to a tank.

[0025] In a first embodiment of the invention, the second solenoid of the check valve element can be configured as an on-off-solenoid. There are many elevator applications that do not need to satisfy USM safety in a very large pressure and flow ranges. In these cases, it is sufficient to use an on-off-solenoid as the second solenoid.

[0026] In a second embodiment of the invention, the housing can comprise a first connection element, the first connection element being connected to the down piston pilot chamber, and a second connection element, the second connection element being connected to the down piston pilot chamber and to the hydraulic control line. The check valve element can comprise a first adjustment element, by means of which the check valve element can be fastened to the first connection element of the housing, and a second adjustment element, by means of which the check valve element can be fastened to the second connection element of the housing. The second adjustment element can provide extra oil flow from the hydraulic control line to the down piston pilot chamber through a fix orifice. Furthermore, the check valve element can comprise a first hydraulic line, the first hydraulic line leading through the first adjustment element and the second solenoid, and a second hydraulic line, the second hydraulic line leading through the second adjustment element and the second solenoid. In this case, the second solenoid can be configured as a double-acting solenoid.

[0027] When both the D-solenoid and the second solenoid are not energized, down movement of the down piston is not possible. In this case, extra oil is fed into the down piston pilot chamber from the hydraulic control line through the second solenoid. If both the D-solenoid and the second solenoid are energized, the control of the down piston movement is done by means of D-solenoid in the same way than is already known from the prior art. If unintended car movement occurs, the second solenoid will be de-energized by the elevator controller. In such a case, extra oil flow from the hydraulic control line to the down piston pilot chamber is enabled by the second solenoid, thereby helping to close the down piston quicker.

[0028] The second adjustment element can also serve as a further output connection.

[0029] Further advantages and features of the invention can be taken from the features additionally specified in the claims and from the exemplary embodiments below.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention will be described and explained in more detail below on the basis of the exemplary embodiments shown in the drawings, in which: Fig. 1shows a first embodiment of the hydraulic control valve with the check valve element, Fig. 2shows the check valve element according to Fig. 1, Fig. 3shows a cross-section of the adjustment element of the check valve element according to Fig. 1 and 2, Fig. 4shows a second embodiment of the hydraulic control valve with the check valve element, Fig. 5shows the check valve element according to Fig. 4, Fig. 6shows a cross-section of the second adjustment element of the check valve element according to Fig. 4 and 5, Fig. 7shows a schematic hydraulic flow diagram of a hydraulic elevator according to the invention with the hydraulic control valve according to Figs. 1 and 2, where both the D-solenoid and the second solenoid are not energized, Fig. 8shows a schematic hydraulic flow diagram according to Fig. 7, where the D-solenoid is energized and the second solenoid is not energized, Fig. 9shows a schematic hydraulic flow diagram according to Figs. 7 and 8, where both the D-solenoid and the second solenoid are energized, Fig. 10shows a schematic hydraulic flow diagram of a hydraulic elevator according to the invention with the hydraulic control valve according to Figs. 4 and 5, where both the D-solenoid and the second solenoid are not energized, Fig. 11shows a schematic hydraulic flow diagram according to Fig. 10, where the D-solenoid is energized and the second solenoid is not energized, Fig. 12shows a schematic hydraulic flow diagram according to Figs. 10 and 11, where both the D-solenoid and the second solenoid are energized, DETAILED DESCRIPTION

[0031] Fig. 1 shows a first embodiment of the hydraulic control valve 10 for a hydraulic elevator 12 with the check valve element 14. The most widely used hydraulic control valve 10 is the EV100 mechanical valve, which has EV0, EV1 and EV10 modules as well. The electronic control valve called SEV and inverter driven control valve EV4 and EV40 are also built on EV100 housing. Thus, all those valves are called EV-type control valves and the new UCM development can be used by all EV-type valves. On an EV-type control valve the number of solenoids may very between one to four. All control valves 10 must have at least one solenoid, which is the D-solenoid 20 for down travel. If the control valve 10 has two speeds in down direction (fast and slow speed) then it also has a C-solenoid. All down solenoids (D-solenoid 20 and C-solenoids) are usually normally closed ones. The other solenoids on the control valve are for the up-direction travel. They have no influence in down direction travel and are therefore not further considered in this application.

[0032] The hydraulic control valve 10 comprises a housing 22 which is shown in fig. 1. The housing comprises a hydraulic control line 24 (see fig. 7), a down piston 26 being positioned in the hydraulic control line 24 and the D-solenoid 20. By means of the D-solenoid 20 a hydraulic line 28 starting at the down piston pilot chamber 30 can be opened or closed, thereby controlling the position of the down piston 26. The hydraulic line 28 ends at a connection element 32 of the housing 22.

[0033] The check valve element 14 can be fastened to the housing 22 via the connection element 32. The check valve element 14 is configured as a separate component and comprises a housing 40 with a second solenoid 42 and an adjustment element 44 (see fig. 3). UCM safety is provided with the serial connection of the second solenoid 42 of the check valve element 14 to the D-solenoid 20 on the hydraulic control valve 10. The down movement will not happen unless both the D-solenoid 20 and the second solenoid 42 are energized (see fig. 9)

[0034] In this first embodiment the second solenoid 42 is configured as an on-off-solenoid 42. The adjustment element 44 is specially designed to fix the housing 40 of the check valve element 14 to the connection element 32 of the hydraulic control valve 10 and to provide a serial connection of the second solenoid 42 to the D-solenoid 20 on the hydraulic control valve 10.

[0035] The adjustment element 44 throttles the return oil from the down piston pilot chamber 30 to the tank 16 of the hydraulic elevator 12 by minimizing the pressure losses during down travel of the elevator 12.

[0036] Fig. 7 to 9 show schematic hydraulic flow diagrams of a first embodiment of a hydraulic elevator 12 according to the invention with the hydraulic control valve 10 according to figs. 1 and 2. The hydraulic control valve 10 has a down piston 26 which is shown in its CLOSED-position 50 in figs. 7 and 8 and in its OPEN-position 52 in fig. 9. In its CLOSED-position 50, the down piston 26 closes the hydraulic control line 24 coming from the elevator car (hydraulic cylinder). Thus, no hydraulic fluid can pass through the hydraulic control line 24 into a storage tank 16. Therefore, the elevator car cannot move downwards.

[0037] In order to transfer the down piston 26 from its CLOSED-position 50 into its OPEN-position 52, both the D-solenoid 20 and the second solenoid 42 have to be energized. The D-solenoid 20 is a Normally-Closed-Solenoid, therefore, no hydraulic oil can pass through it and leave the down piston plot chamber 30 via the hydraulic line 28. The second solenoid 42 is connected via a hydraulic line 54 of the adjustment element 44 to the D-solenoid 20 and is also configured as a normally closed on-off-solenoid.

[0038] As hydraulic oil from the hydraulic control line 24 is fed into the down piston pilot chamber 30 via a further hydraulic line 56, the pressure in the down piston pilot chamber 30 keeps the down piston 26 closed and down movement of the down piston 26 is not possible. The hydraulic line 56 is usually throttled manually to provide smooth opening and closing of the down piston 26.

[0039] If only the second solenoid 42 is energized, there is still no down movement of the down piston 26 possible, as the D-solenoid 20 remains closed (Normally-Closed-Solenoid). Thus, there is now flow of the hydraulic oil through the hydraulic line 54 of the adjustment element 44 and no hydraulic oil can leave the down piston pilot chamber 30. The oil pressure in the down piston pilot chamber 30 keep the down piston 26 closed and down movement of the down piston 26 is not possible.

[0040] If only the D-solenoid 20 is energized (see fig. 8), hydraulic oil can still not leave the down piston pilot chamber as the second solenoid 42 closes the oil flow through the adjustment element 44 and its second hydraulic line 58. Hydraulic oil from the hydraulic control line 24 is still fed into the down piston pilot chamber 30 via the further hydraulic line 56. Therefore, the pressure in the down piston pilot chamber 30 keeps the down piston 26 closed and down movement of the down piston 26 is not possible.

[0041] If both the D-solenoid 20 and the second solenoid 42 are energized (see fig. 9), the hydraulic lines 54 and 58 through the adjustment element 44 are both open. The hydraulic oil reaches the adjustment element 44 coming from the hydraulic line 28 from the down piston pilot chamber 30 and passes through the adjustment element 44 via the hydraulic line 54. After passing the open second solenoid 42 the hydraulic oil can pass the adjustment element 44 via the hydraulic line 58 and can go to the tank 16. Thus, the adjustment element 44 also serves as an output connection 60 for connecting the hydraulic control valve 10 via the check valve element 14 to a tank 16. Therefore, the pressure in the down piston pilot chamber 30 drops and the down piston 26 opens to allow down travel.

[0042] If the second solenoid 42 is de-energized during down travel, the second solenoid 42 closes the oil flow though the adjustment element 44. Therefore, the oil flow from the down piston pilot chamber 30 to the tank 16 stops but hydraulic oil is still fed from the hydraulic control line 24 to the down piston pilot chamber 30 via the hydraulic line 56. The pressure in the down piston pilot chamber 30 increases and the down piston 26 closes. Therefore, the elevator stops and down movement is no longer possible.

[0043] Fig. 4 shows a second embodiment of the hydraulic control valve 10.2 for a hydraulic elevator 12 with the check valve element 14.2. The hydraulic control valve 10.2 comprises a housing 22.2 which is shown in fig. 4. The housing 22.2 comprises a hydraulic control line 24 (see fig. 10), a down piston 26 being positioned in the hydraulic control line 24 and the D-solenoid 20. By means of the D-solenoid 20 the hydraulic line 28 starting at the down piston pilot chamber 30 can be opened or closed, thereby controlling the position of the down piston 26. The hydraulic line 28 ends at a first connection element 32 of the housing 22.2. Furthermore, there is a second connection element 70 in the housing 22.2

[0044] The check valve element 14.2 can be fastened to the housing 22.2 via both the first connection element 32 and the second connection element 70. The check valve element 14.2 is configured as a separate component and comprises a housing 40.2 with a second solenoid 42.2 and a first adjustment element 44 (see fig. 3). UCM safety is provided with the serial connection of the second solenoid 42.2 of the check valve element 14.2 to the D-solenoid 20 on the hydraulic control valve 10.2. The down movement will not happen unless both the D-solenoid 20 and the second solenoid 42.2 are energized (see fig. 12).

[0045] In this second embodiment the second solenoid 42.2 is configured as a double-acting solenoid 42.2. The adjustment element 44 is specially designed to fix the housing 40.2 of the check valve element 14.2 to the first connection element 32 of the hydraulic control valve 10.2 and to provide a serial connection of the second solenoid 42.2 to the D-solenoid 20 on the hydraulic control valve 10.2. Furthermore, the check valve element 14.2 is connected to the second connection element 70 via a second adjustment element 72 (see fig. 6).

[0046] The second adjustment element 72 feeds hydraulic oil from the hydraulic control line 24 into the down piston pilot chamber by two ways. One is through a hydraulic line 74 which is connected to the hydraulic line 56 of the hydraulic control valve 10.2. This hydraulic line 74 is always open and usually throttled manually by the second adjustment element 72 to provide smooth opening and closing of the down piston 26. Furthermore, there is a second hydraulic line 76 passing through the second adjustment element 72. This second hydraulic line 76 also passes through the second solenoid 42.2, thus this second hydraulic line 76 can be opened or closed by the second solenoid 42.2. Extra hydraulic oil can be fed to the down piston pilot chamber 30 to allow quick closing of the down piston 26 when UCM condition occurs.

[0047] The adjustment element 44 throttles the return oil from the down piston pilot chamber 30 to the tank 16 of the hydraulic elevator 12 by minimizing the pressure losses during down travel of the elevator 12.

[0048] Fig. 10 to 12 show schematic hydraulic flow diagrams of a second embodiment of a hydraulic elevator 12.2 according to the invention with the hydraulic control valve 10.2 according to figs. 4 and 5. The hydraulic control valve 10.2 has a down piston 26 which is shown in its CLOSED-position 50 in figs. 10 and 11 and in its OPEN-position 52 in fig. 12. In its CLOSED-position 50, the down piston 26 closes the hydraulic control line 24 coming from the elevator car. Thus, no hydraulic fluid can pass through the hydraulic control line 24 into a storage tank 16. Therefore, the elevator car cannot move downwards.

[0049] In order to transfer the down piston 26 from its CLOSED-position 50 into its OPEN-position 52, both the D-solenoid 20 and the second solenoid 42.2 have to be energized. The D-solenoid 20 is a Normally-Closed-Solenoid, therefore, no hydraulic oil can pass through it and leave the down piston pilot chamber 30 via the hydraulic line 28.

[0050] The second solenoid 42.2 is connected via a hydraulic line 54 of the first adjustment element 44 to the D-solenoid 20 and is configured as a double-acting solenoid. The second solenoid 42.2 is not energized, thereby closing the oil flow through the hydraulic line 54 of the first adjustment element 44. At the same time, the second solenoid 42.2 opens the hydraulic line 76 of the second adjustment element 72, thereby allowing extra oil from the hydraulic control line 24 being fed into the down piston pilot chamber 30.

[0051] As hydraulic oil from the hydraulic control line 24 is fed into the down piston pilot chamber 30 via the further hydraulic line 56 passing through the second adjustment element 72, the pressure in the down piston pilot chamber 30 keeps the down piston 26 closed and down movement of the down piston 26 is not possible. The hydraulic line 58 is usually throttled via the adjustment element 44 to provide smooth opening and closing of the down piston 26.

[0052] If only the second solenoid 42.2 is energized, there is still no down movement of the down piston 26 possible, as the D-solenoid 20 remains closed (Normally-Closed-Solenoid). Thus, there is no flow of the hydraulic oil through the hydraulic line 54 of the adjustment element 44 and no hydraulic oil can leave the down piston pilot chamber 30. Extra oil flown from the hydraulic control line 24 via the second adjustment element 72 to the down piston pilot chamber 30 stops and no hydraulic oil can leave the down piston pilot chamber 30. The oil pressure in the down piston pilot chamber 30 keep the down piston 26 closed and down movement of the down piston 26 is not possible.

[0053] If only the D-solenoid 20 is energized (see fig. 11), hydraulic oil can still not leave the down piston pilot chamber as the second solenoid 42.2 closes the oil flow through the adjustment element 44 and its second hydraulic line 58. Hydraulic oil from the hydraulic control line 24 is still fed into the down piston pilot chamber 30 via the further hydraulic line 56 and the hydraulic lines 74 and 76 of the second adjustment element 72. Thus, no hydraulic oil can leave the down piston pilot chamber 30 but additionally more oil is fed in. Therefore, the pressure in the down piston pilot chamber 30 keeps the down piston 26 closed and down movement of the down piston 26 is not possible.

[0054] If both the D-solenoid 20 and the second solenoid 42.2 are energized (see fig. 12), the hydraulic lines 54 and 58 through the adjustment element 44 are both open. The hydraulic oil reaches the adjustment element 44 coming from the hydraulic line 28 from the down piston pilot chamber 30 and passes through the adjustment element 44 via the hydraulic line 54. After passing the open second solenoid 42.2 the hydraulic oil can pass the adjustment element 44 via the hydraulic line 58 and can go to the tank 16. Furthermore, the second solenoid 42.2 closes the further hydraulic line 76 through the second adjustment element 72 so hydraulic oil can only flow into the down piston pilot chamber 30 via the hydraulic line 56. Therefore, the pressure in the down piston pilot chamber 30 drops and the down piston 26 opens to allow down travel.

[0055] If the second solenoid 42.2 is de-energized during down travel, the second solenoid 42.2 closes the oil flow though the adjustment element 44. Therefore, the oil flow from the down piston pilot chamber 30 to the tank 16 stops but hydraulic oil is still fed from the hydraulic control line 24 to the down piston pilot chamber 30 via the hydraulic line 56 and the second adjustment element 72. Additionally, extra oil is fed from the hydraulic control line 24 to the down piston pilot chamber 30 via the further hydraulic line 76 of the second adjustment element 72. The pressure in the down piston pilot chamber 30 increases and the down piston 26 closes. Therefore, the elevator stops and down movement is no longer possible.

[0056] Control valves other than those shown in figures 1 and 4 can also utilize the inventions by adapting and adaptor plate between the check valve element and the connecting elements of those valves.

Claims

1. Hydraulic elevator (12, 12.2) - with an elevator car, which can be moved vertically in an elevator shaft, - with a hydraulic control valve (10, 10.2) by means of which the lowering of the elevator car can be controlled, - wherein the hydraulic control valve (10, 10.2) has a down piston (26), by means of which a hydraulic control line (24) from the elevator car to a storage tank (16) can be opened or closed, - wherein the position of the down piston (26) can be controlled by a D-solenoid (20), by means of which a hydraulic line (28) from the down piston pilot chamber (30) to the tank (16) can be opened or closed, - characterized in that - there is a second solenoid (42, 42.2) positioned in the hydraulic line (28) from the down piston pilot chamber (30) to the tank (16), - the second solenoid (42, 42.2) is positioned between the D-solenoid (20) and the tank (16).

2. Hydraulic elevator according to claim 1, - characterized in that - the D-solenoid (20) is configured as an on-off-solenoid.

3. Hydraulic elevator according to claim 1 or 2, - characterized in that - the second solenoid (42) is configured as an on-off-solenoid.

4. Hydraulic elevator according to claim 1 or 2, - characterized in that - the second solenoid (42.2) is configured as a double-acting solenoid, - the second solenoid (42.2) is positioned between the hydraulic control line (24) and the down piston pilot chamber (30).

5. Hydraulic elevator according to claim 4, - characterized in that - both the D-solenoid (20) and the second solenoid (42.2) are positioned in the hydraulic line (28) from the down piston pilot chamber (30), - the second solenoid (42.2) is positioned in a second hydraulic line (76) connected to the hydraulic line (56) between the hydraulic control line (24) and the down piston pilot chamber (30).

6. Hydraulic control valve (10, 10.2) for a hydraulic elevator (12, 12.2), - with a housing (22, 22.2), - with a hydraulic control line (24), - with a down piston (26) which is positioned in the hydraulic control line (24), - with a hydraulic line (28) starting at the down piston pilot chamber (30) and ending at a connection element (32) in the housing (22), - with a D-solenoid (20), by means of which the hydraulic line (28) from the down piston pilot chamber (30) to the connection element (32) can be opened or closed, thereby controlling the position of the down piston (26), - characterized in that - there is a check valve element (14, 14.2) present which is configured as a separate component and which can be fastened to the housing (22, 22.2) via the connection element (32), - wherein the check valve element (14, 14.2) comprises a hydraulic line (54) between the connection element (32) of the housing (22, 22.2) and an output connection (60), - wherein the check valve element (14, 14.2) comprises a second solenoid (42, 42.2) being positioned in the hydraulic line (54).

7. Hydraulic control valve according to claim 6, - characterized in that - the D-solenoid (20) is configured as an on-off-solenoid.

8. Hydraulic control valve according to claim 6 or 7, - characterized in that - the check valve element (14, 14.2) comprises an adjustment element (44), by means of which the check valve element (14, 14.2) can be fastened to the connection element (32) of the housing (22), - the hydraulic line (54) of the check valve element (14, 14.2) leads through the adjustment element (44).

9. Hydraulic control valve according to claim 8, - characterized in that, - the adjustment element (44) also serves as output connection (60).

10. Hydraulic control valve according to one of claims 6 to 9, - characterized in that, - the second solenoid (42) is configured as an on-off-solenoid.

11. Hydraulic control valve according to one of claims 6 to 9, - characterized in that, - the housing (22.2) comprises a first connection element (32), the first connection element (32) being connected to the down piston pilot chamber (30), - the housing (22.2) comprises a second connection element (70), the second connection element (70) being connected to the down piston pilot chamber (30) and to the hydraulic control line (24), - the check valve element (14.2) comprises a first adjustment element (44), by means of which the check valve element (14.2) can be fastened to the first connection element (32) of the housing (22.2), and a second adjustment element (72), by means of which the check valve element (14.2) can be fastened to the second connection element (70) of the housing (22.2).

12. Hydraulic control valve according to claim 11, - characterized in that, - the second solenoid (42.2) is configured as a double-acting solenoid, - a first hydraulic line (54) of the check valve element (14.2) leads through the first adjustment element (44) and the second solenoid (42.2), - a second hydraulic line (76) of the check valve element (14.2) leads through the second adjustment element (72) and the second solenoid (42.2).

13. Hydraulic control valve according to claim 11 or 12, - characterized in that, - the second adjustment element (72) also serves as output connection.

14. Hydraulic control valve according to one of claims 6 to 13, - characterized in that, - there is an adapter plate present between the check valve element and the at least one connection element of the control valve.

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