WO2002083542A1

WO2002083542A1 - Emergency device for automatic operation of a hydraulic lift

Info

Publication number: WO2002083542A1
Application number: PCT/FR2001/001186
Authority: WO
Inventors: Emile Kadoche
Original assignee: Nk System N.V.
Priority date: 2001-04-18
Filing date: 2001-04-18
Publication date: 2002-10-24

Abstract

The emergency device for automatic operation of a hydraulic lift whereof the circuit comprises an actuator and a pressure accumulator, comprises a core (30) mounted mobile in a cylinder (20) whereof a chamber (32) is permanently connected to the actuator and selectively to a discharge reservoir (14) through an electromagnetic valve (34) and whereof the other chamber (31) is selectively connected to the accumulator through a first electromagnetic valve (26). In case of power failure and the lift is between two floors, a timed switch opens the first electromagnetic valve (26), thereby displacing the core (30) on the basis of pressure differences. The first electromagnetic valve (26) remains open if the pressure in the accumulator is higher than the pressure in the actuator so as to cause the lift to be elevated to the upper floor. In the opposite case, the second electromagnetic valve (34) is open, and the lift goes down to the lower floor.

Description

Automatic emergency operation device for a hydraulic lift

The invention relates to an automatic emergency operation device for an elevator blocked between two floors in the event of a power failure.

The automatic emergency maneuver allows elevator users to be able to reach the floor in the event of a power failure. This possibility exists today in elevators driven by electric motors with a substantial auxiliary energy supply. In hydraulic type elevators, in which the cage is actuated by a hydraulic cylinder, it is possible to lower the elevator to the lower floor by discharging part of the pressurized fluid contained in the working chamber of the cylinder in the discharge tank, by means of a restriction valve.

In order to reduce the power of the electric motor necessary to drive the oil circulation pump in the hydraulic circuit of an elevator, FR 2773 142 has proposed using a pressure accumulator as a source of fluid.

The object of the invention is to equip an elevator of the type described in FR 2773 142 with an emergency device which can use, under certain conditions, the energy stored in the pressure accumulator to mount the 'lift to the upper floor in the event of a main electric power cut.

The invention therefore relates to an emergency device for automatically bringing an elevator of the hydraulic type, the hydraulic circuit of which comprises a hydraulic cylinder and a pressure accumulator, to an upper or lower stage in the event of a power failure and the elevator being between two floors.

According to the invention, this device is characterized in that it comprises: a core mounted mobile in a cylinder and sharing the internal cavity of said cylinder in a first chamber capable of communicating with the accumulator following the opening of a first solenoid valve, and a second communicating chamber permanent with the working chamber of the jack and capable of further communicating with a discharge tank, following the opening of a second solenoid valve, a conduit formed in the core between the first chamber and the second chamber, means for closing off selectively said conduit, said means allowing a transfer of fluid from the first chamber to the second chamber when the volume of the second chamber is minimum, means for opening the first solenoid valve for a determined period, in the event of a power failure and the elevator being between two stages, so that the core moves towards one end of the cylinder under the action of the pressure differences prevailing in the accumulator and in the working chamber, means for keeping the first solenoid valve open if the volume of the second bedroom is minimum, in order to raise the elevator to the upper floor and, means to open the second electric valve if the volume of the second bedroom is maximum, in order to bring the elevator down to the lower floor.

Thus, in the event of a power failure and if the elevator is between two floors, the first solenoid valve opens for a determined period. The pressure accumulator is then in communication with the first chamber. The core then moves towards one end of the cylinder as a function of the pressures prevailing in the first chamber and the second chamber, that is to say as a function of the pressures of the fluid in the accumulator and in the working chamber of the jack. If the pressure in the cylinder is greater than the pressure in the accumulator, the volume of the first chamber is minimum and the volume in the second chamber is maximum. The conduit formed in the core is then closed, the second solenoid valve is open, and part of the hydraulic fluid contained in the working chamber of the jack flows to the discharge tank by passing through the second chamber. The elevator goes down. The two solenoid valves are closed again when the elevator reaches the lower floor. On the other hand, if the pressure prevailing in the accumulator is greater than the pressure prevailing in the working chamber of the jack, the volume of the first chamber is maximum and the volume of the second chamber is minimum. The first solenoid valve remains in the open state, the second solenoid valve is closed, and the conduit allows fluid transfer from the first chamber to the second chamber. In other words, fluid flows from the accumulator to the working chamber of the jack, passing through the conduit formed in the core, which causes the lift to rise. When the elevator reaches the upper floor, the two solenoid valves are closed again, which immobilizes the elevator on this floor.

The following advantageous arrangements are also preferably adopted: - the means for selectively closing said conduit comprise a valve disposed in the orifice of said conduit on the side of the first chamber and a rod accommodating partly in said conduit and partly in the second chamber, said rod opening said valve when its end abuts on an end wall of the cylinder;

- The means for keeping the first solenoid valve open comprise a switch actuated by a first control secured to the core;

- The means for opening the second solenoid valve comprise a switch actuated by a second control integral with the core;

- The means for opening the first solenoid valve for a determined period comprise a timed switch;

- the first solenoid valve and the second solenoid valve are supplied by a low voltage current;

- the power supply circuit of the first solenoid valve and the second solenoid valve includes in series a first switch closed in the event of a power failure and a second switch closed when the elevator is between two floors; - The second chamber has a spring which tends to move the core towards the first chamber.

Thanks to this spring, the hydraulic circuit, between the pressure accumulator and the jack, will only be established via the device if the pressure in the accumulator is higher than the pressure in the working chamber of the jack, of a value guaranteeing the certain rise of the lift to the next upper floor.

Other characteristics and advantages of the invention will emerge on reading the following description given by way of example and with reference to the appended drawings in which:

- Figure 1 is a schematic and simplified view of the hydraulic circuit controlling the displacement cylinder of an elevator, equipped with an emergency operating device according to the invention; - Figure 2 is a sectional view on a larger scale of the emergency operating device according to the invention; and

- Figure 3 is a block diagram of the electrical circuit controlling the solenoid valves of the emergency operation device according to the invention. In FIG. 1, the reference 1 shows a cylinder body in which a piston 10 fitted with a piston rod is slidably mounted and the pressure chamber 1a of which is connected to a closing valve 9.

This closing valve 9 is connected to the inlet of a pump 11 by a downcomer 15 in which are mounted in series a first solenoid valve 2 and a first non-return valve 3, and to the outlet of the pump 11 by an ascent conduit 16 in which are mounted in series a second solenoid valve 6 and a second non-return valve 5. A third solenoid valve 6a is mounted in a first bypass conduit 15a, provided between a pressure accumulator 4 and the descent conduit 15, this first bypass conduit 15a joining the descent conduit 15 between the non-return valve 3 and the pump 11. A fourth solenoid valve 2a is mounted in a second bypass conduit 16a, provided between the accumulator 4 and the conduit climb 16, this second bypass duct 16a joining the climb duct 16 between the solenoid valve 6 and the pump 11. A pressure relief valve 17, connected to an oil reservoir 14, is provided at the outlet of the pump 11 on the ascent pipe 16. The inlet of the pump is furthermore connected to the oil tank 14 by a suction pipe 18 fitted with a non-return valve 19. A fifth solenoid valve 8 is mounted on a third bypass pipe 20 which connects the accumulator 4 to the rise pipe 16 in one point located between the pressure relief valve 17 and the solenoid valve 6. A pressure indicator 7 indicates the pressure in the pressure accumulator 4. Finally, the shut-off valve 9 is connected to the oil tank 14 by an emergency pipe 21 fitted with a manual pump 13. The pump 11 is rotated by an electrically regulated motor 12.

During the rise of the elevator, the solenoid valves 2, 2a and 8 are closed. The solenoid valves 6 and 6a and the closing valve 9 are open.

During the descent of the elevator, the solenoid valves 6, 6a and 8 are closed. The solenoid valves 2, 2a and the closing valve 9 are open.

When the elevator is immobilized, all of the solenoid valves 2, 2a, 6, 6a and 8, as well as the closing valve 9 are closed.

When it is desired to recharge the pressure accumulator 4 with oil, the solenoid valves 2, 2a, 6 and 6a are closed and the solenoid valve 8 is open. The pump 11, actuated by the motor 12, sucks oil into the reservoir 14 through the suction pipe 18 and discharges it into the accumulator 4 through the third bypass pipe 20.

When the elevator is in the low position, the piston 10 is returned to the cylinder body 1, and the volume of the pressure chamber 1a of the cylinder 1 is minimum. In this condition, the oil used to move the cylinder body is stored under high pressure in the pressure accumulator 4. Conversely, when the elevator is in the high position, the piston rod 10 is deployed at the outside the cylinder body 1, and the volume of the pressure chamber 1a of the cylinder 1 is maximum. In this position, little oil is in the pressure accumulator 4 and the pressure in the pressure accumulator is at its minimum value. At the start of the lift climb, the pressure of the oil in the pressure accumulator 4 will produce the forces necessary to drive the lift up. When the pressure in the pressure accumulator 4 becomes insufficient to compensate for the load of the elevator, as a result of the transfer of the oil to the chamber 1a of the jack, the motor 12 will supply the pump 11 with additional energy.

Conversely, at the start of the descent of the elevator, the load of the latter will allow a transfer of fluid from the pressure chamber 1a of the jack 1 to the pressure accumulator 4 without the aid of the motor 12. When the pressure in the pressure accumulator 4 will have reached an average value, the motor 12 will drive the pump 11 and will pump the oil from the chamber 1a of the jack to introduce it under pressure into the pressure accumulator 4.

The energy consumed by the motor 12 serves only to compensate for the maximum pressure differences existing in the pressure chamber 1a of the jack 1 and in the pressure accumulator 4 in the high and low positions of the elevator.

When the pressure indicator 7 justifies the needs, the solenoid valve 8 opens to allow recharging of the accumulator 4, by the pump 11.

The piston 10 represented by a rod in the body of the jack

I is deployed outwards by the oil pressure arriving by the closing valve 9, when the solenoid valves 6 and 6a are open. The piston returns inside the cylinder body when the free end of the rod under the effect of the load and by gravitation itself provides pressure on the piston as soon as the solenoid valves 2 and 2a are open. The pump 11 is driven in the same direction of rotation according to the descent needs and mounted by the electrically regulated motor 12. It is therefore understood that by controlling the movement of the cabin in the direction mounted by the solenoid valves 6 and 6a, the pump

II and the motor 12 hardly need to provide any effort, due to the presence in the circuit of the pressure accumulator 4 which itself and instantly delivers the needs necessary to move the device. We can see an immediate start of the elevator, and without waiting. The cab travel cycle is invariably reversed. The displacement of the cabin downhill under the effect of gravitation, creates pressure at the base of the jack; the invention that interests us is to use this energy wisely in order to reuse it.

The pump 11 provides no effort, most of the time of the descent of the elevator, and would even tend to produce current, this energy is channeled to the pressure accumulator 4. The pump 11 provides the needs related to the speed of the device, thus ensuring a perfect flow of the quantity of oil necessary for the cylinder.

The solenoid valve 8 makes it possible to recharge the accumulator if necessary, and according to the pressure indicated on the pressure controller 7. This action is provided for the first start-up, and in the case of work or parking the cabin in bottom of the sheath, or to prevent a possible leak. The current operating charge of the accumulator 4 is provided and ensured by the action of the piston 10.

The hand pump 13 is installed between the reservoir 14 and the closing valve 9, its presence is purely symbolic. It is intended for possible displacement of the jack before the installation of the accumulator 4.

The reference 20 represents an automatic emergency operating device disposed between the pressure chamber 1a of the jack 1 and the pressure accumulator 4. This device 20 essentially comprises a hollow cylinder 21, one end 22 of which is connected to the pressure chamber 1a by a conduit 23, and the other end 24 of which is connected to the accumulator 4 by a conduit 25 in which is mounted a solenoid valve 26. A core 30 is movably mounted in the internal cavity of the cylinder 21. This core 30 shares the internal volume of the cylinder 21 in a first chamber 31 on the side of the end 24 connected to the accumulator 4, and a second chamber 32 on the side of the end 22 permanently connected to the pressure chamber 1a. The second chamber 32 is also connected to the reservoir 14 by a conduit 33 in which another solenoid valve 34 is mounted. The conduit 33 opens into the internal cavity of the cylinder 21 by an orifice 34 provided on its side wall which can be closed by the core 30 when the volume of the second chamber 32 is not maximum.

The operating device 20 is shown in detail in FIG. 2. The solenoid valves 26 and 37 can be mounted on the cylinder body 21 so as to constitute a one-piece emergency device.

In the second chamber 32 is provided a spring 35 which exerts on the core 30 a force tending to push it towards the first chamber 31. A conduit 40 is formed in the core 30. This conduit 40 puts the first chamber 31 in communication with the second chamber 32. This conduit 40 opens into the first chamber 31 through a cavity 41 in which is mounted a valve 42 which normally closes the orifice of the conduit 40. A rod 43 partially accommodates in the conduit 40. This rod 43 has a portion in the second chamber 32. When the core 30 is moved towards the end wall 22 of the cylinder 21, that is to say when the volume of the second chamber 32 is small, the rod 43 abuts against this wall 22 and its other end causes the valve 42 to open.

In this condition, the first and second chambers 31 and 32 communicate with each other through the space of the conduit 40 which surrounds the rod 43.

To the core 30 is fixed a control rod 50 parallel to the axis of the cylinder 21 which comprises controls making it possible to selectively close two electrical switches 61, 62, making it possible to open the solenoid valve 26 and the solenoid valve 34 respectively.

FIG. 3 shows the electrical diagram associated with the device 20 described above.

The solenoid valves 26 and 34 are controlled respectively by coils 26a and 34a mounted in parallel in an electrical circuit 60 supplied with low voltage. This circuit 60 comprises, in series, a first switch 63, which is in the closed position in the event of a cut in the supply current to the motor 12 driving the pump 11 of the hydraulic circuit of the elevator, and a second switch 64 which is in the closed position when the elevator is between two floors.

When there is current to supply the electric motor 12, the switch 63 is open, the solenoid valves 26 and 34 are then closed and the device 20 is inoperative.

When the elevator is on one floor, the switch 64 is open, the solenoid valves 26 and 34 are closed. The device 20 is also inoperative.

In the bypass containing the coil 26a for controlling the solenoid valve 26, a timed switch 65 is provided which closes when the switch 63 closes and which opens after a predetermined time, for example three seconds.

When the switch 63 closes after a power failure, the switch 65 will close for three seconds, and the coil 26a will be supplied with current, provided that the switch 64 is also closed, it that is, the elevator is blocked between two floors.

The solenoid valve 26 is then opened for a period of three seconds. The fluid of the accumulator 4 enters the first chamber 31.

If the force of the pressures exerted on one face of the core 30 in the first chamber 31 is greater than the force of the pressures exerted on the other face of the core in the second chamber 32 increased by the force of the spring 35, the core 30 will move in the cylinder 21 towards the end wall 22. The volume of the second chamber 32 is then minimum. The rod 43 pushes back the valve 42. The orifice 40 is open. The control rod 50 closes the switch 61, which ensures that the solenoid valve 26 will remain open, even after the opening of the switch 65 after three seconds, as long as the switches 63 and 64 remain closed.

In the situation described above, the accumulator 4 delivers hydraulic fluid to the pressure chamber 1a, through the device 20. The elevator rises to the next upper floor. When it is returned to this stage, the switch 64 opens, and the device 20 becomes inoperative. On the other hand, if the pressure in the first chamber 31 is insufficient to compensate for the pressure in the second chamber 32 and the force of the spring 35, the core 30 moves towards the end wall 24. The duct 40 remains closed. The control rod 50 closes the switch 62. After three seconds, the switch 65 opens. As can be seen in FIG. 3, the coil 34a of the solenoid valve 34 is supplied with current and remains supplied with emergency current as long as the switches 63 and 64 are closed. The volume of the second chamber 32 being maximum, and the solenoid valve 34 being open, part of the hydraulic fluid flows from the pressure chamber 1a to the discharge tank 14 passing through the second chamber 32. The elevator descends and, when it is returned to the next lower level, the switch 64 opens and the device 20 becomes inoperative. In the case where the device 20 described above is in operation and if in the meantime the supply current of the electric motor 12 returns, the switch 63 opens and the device 20 becomes inoperative, the solenoid valves 26 and 34 being of again closed. The solenoid valves 26 and 34, as well as the conduit 40 are calculated so as to provide a low flow of fluid in order to control the speed of descent or ascent of the elevator.

Claims

1lREVENDICATIONS

1. Emergency device for automatically bringing an elevator of the hydraulic type, the hydraulic circuit of which comprises a hydraulic cylinder (1) and a pressure accumulator (4), to an upper or lower stage in the event of a power failure and the elevator being between two stages, characterized in that it comprises: a core (30) mounted mobile in a cylinder (21) and dividing the internal cavity of said cylinder in a first chamber

(31) capable of communicating with the accumulator (4) following the opening of a first solenoid valve (26), and a second chamber (32) in permanent communication with the working chamber (1a) of the jack (1) and capable of further communicating with a discharge tank (14) following the opening of a second solenoid valve (34), a conduit (40) formed in the core (30) between the first chamber (31) and the second chamber (32), means (42, 43) for selectively closing said conduit (40), said means allowing a transfer of fluid from the first chamber (31) to the second chamber (32) when the volume of the second chamber ( 32) is minimum, means (65) for opening the first solenoid valve (26) for a determined period of time, in the event of a power failure and the elevator being between two stages, so that the core (30) moves towards one end of the cylinder (21) under the action of the pressure differences prevailing in the accumulator r (4) and in the working chamber (1a), means (61) for keeping the first solenoid valve (26) open if the volume of the second chamber (32) is minimum, in order to raise the elevator towards the 'upper floor and, means (62) for opening the second solenoid valve (34) if the volume of the second chamber (32) is maximum, in order to bring the elevator down to the lower floor.

2. device according to claim 1, characterized in that the means for selectively closing said conduit (40) comprise a valve (42) disposed in the orifice (41) of said conduit (40) on the side of the first chamber (31) and a rod (43) accommodating partly in said conduit (40) and partly in the second chamber (32), said rod (43) opening said valve (42) when its end is in abutment on an end wall (22) of the cylinder (21).

3. Device according to any one of claims 1 or 2, characterized in that the means for holding the first solenoid valve (26) open comprise a switch (61) actuated by a first control integral with the core (30).

4. Device according to any one of claims 1 or

2, characterized in that the means for opening the second solenoid valve (34) comprise a switch (62) actuated by a second control integral with the core (30).

5. Device according to any one of claims 1 or 2, characterized in that the means for holding the first solenoid valve (26) open and the means for opening the second solenoid valve (34) are constituted by switches (61, 62 ) selectively activated by activators integral with the core.

6. Device according to claim 5, characterized in that the activators are formed on a rod (50) integral with the core.

7. Device according to one of claims 1 to 6, characterized in that the means for opening the first solenoid valve (26) for a determined period comprise a timed switch (65).

8. Device according to any one of claims 1 to

7, characterized in that the first solenoid valve (26) and the second solenoid valve (34) are supplied by a low voltage current.

9. Device according to any one of claims 1 to 8, characterized in that the electrical supply circuit in the first solenoid valve (26) and the second solenoid valve (34) comprises in series a first switch (63) closed in the event of a power failure and a second switch (64) formed when the elevator is between two floors.

10. Device according to any one of claims 1 to

9, characterized in that the second chamber (32) has a spring (35) which tends to move the core (30) towards the first chamber (31).