FR2782505A1 - Hydraulic system for operating elevator includes a hydraulic actuator which supports a load subject to gravity - Google Patents

Abstract

The hydraulic system includes a hydraulic actuator (3) which supports a load subject to gravity. A pressurized hydraulic circuit (1) is constituted by an energy accumulator (2) connected to a hydraulic pump (4) which is itself connected to the actuator through hydraulic connections (5,6). A selection valve (10) is arranged between the connections and a non-return valve (18) is interposed between the valve and the pump. The pump passes a pre-specified flow of fluid in the circuit to cause displacement of the actuator in one direction or another.

Description

i

  HYDRAULIC DEVICE FOR ELEVATOR MANEUVER

  The present invention relates to a hydraulic device for reciprocating a load subjected to an opposing force continuously opposing one

  of the directions of movement of this charge.

  The invention applies in particular to lifts fitted with such a hydraulic device in which the load consists of a cabin which is subjected to gravity at

  during the up and down movements.

  The lifts conventionally encountered have drive systems which must be able to drive in

  often very heavy cabs up and down.

  Also, the drive systems are very bulky and are generally placed either at the top of the building in which the elevator is placed, or at the base of this building. They are generally annoying and are complicated to

  implant in the architecture of the building.

  The object of the invention is to solve the drawbacks mentioned above by providing a hydraulic drive device which is compact in order to facilitate its installation while being reliable and

inexpensive in energy.

  To this end, according to the invention, a hydraulic device of the aforementioned type, is essentially characterized in that it comprises a pressurized hydraulic circuit comprising: - at least one hydraulic energy accumulator in which is stored a fluid whose pressure depends on the amount of fluid stored; - a hydraulic actuator linked to the load; and - a hydraulic pump which communicates on the one hand with the accumulator and on the other hand with the actuator by being interposed between them, the hydraulic pump being adapted to impose a predetermined flow of fluid selectively expelled out of the accumulator towards the actuator and stored in the accumulator from the actuator, respectively when the load moves in a first direction against the opposing force opposing this movement and when the load returns according to the second direction of movement, the volume of fluid stored in the accumulator being at least equal to the volume necessary to move the actuator

over its entire course.

  Thus, the device according to the invention is easily implantable and consumes little energy insofar as the power required is essentially supplied by the pressurized fluid contained in the accumulator and therefore by the potential energy of the charge. The energy developed during the downward movement is somehow recovered to be reused

during the upward movement.

  The hydraulic device according to the invention may possibly also include one or more of the following characteristics: - the pressure and the volume of the fluid stored in the accumulator being adapted so that the load moves by itself in the second direction of movement , the pump being adapted to then brake the transfer of the fluid to the accumulator; the hydraulic pump is a unidirectional pump connected to the accumulator and to the actuator respectively by a first and a second hydraulic connection, at least one selection valve being disposed on these two connections to maintain a direction of flow of the fluid in the pump independent of the direction of movement of the load; - a non-return valve is interposed between the selection valve and the pump to maintain the load in a predetermined position after stopping the pump; - a relief valve is interposed between the selection valve and the non-return valve to return the fluid to a reservoir during an overpressure occurring in the circuit; - a pipe connects the reservoir to the second connection to bring the fluid sent into the reservoir to the accumulator; - a non-return valve is mounted on the pipe; - The hydraulic pump includes a drive motor and pumping component parts, between which is interposed an anti-dinghy housing allowing said pumping component parts not to operate as a motor; and - the hydraulic pump is a unidirectional pump connected to the accumulator and to the actuator by a first and a second hydraulic connection which are extended respectively by two conduits on which are mounted cut-off valves coupled to non-return valves of so the pump is unidirectional

  whatever the direction of movement of the load.

  The invention further relates to an elevator on board which is installed the hydraulic device having

  one or more of the features mentioned above.

  Two embodiments of the invention will now be described with reference to the accompanying drawings in which: - Figure 1 schematically shows a first embodiment of the hydraulic device according to the present invention intended to be installed on board an elevator; and - Figure 2 is a view similar to that of the

  figure! of a second embodiment of the hydraulic device.

  The hydraulic device 1 shown in FIG. 1 is intended to be installed on board an elevator having a cabin (not shown) driven up and down by means of a hydraulic actuator 3

which here takes the form of a piston.

  The hydraulic device I according to the present invention consists of a series of hydraulic energy accumulators 2 which are connected via a first hydraulic connection 5 to a hydraulic pump 4 which also communicates by a second

  hydraulic connection 6 with the hydraulic actuator 3.

  The accumulators 2 consist of chambers in which is stored a hydraulic fluid, such as for example oil, under a certain predetermined maximum pressure. These accumulators can in particular be hydropneumatic. The hydraulic pump 4 is a motorized pump which includes a motor 7 itself connected to the parts

  pumping components of the pump by an anti-

  mechanical return 8 also known as a dinghy housing.

  The motor 7 is preferably a variable speed electric motor which makes it possible to adjust the speed of rotation of the pump. The pumping components are of indifferent technology provided that the assembly has good performance (efficiency, pulsations). The invariable nature of the direction of rotation of the pump is ensured by the presence of the anti-diverter unit 8 operating at the

freewheeling way.

  In order to ensure the operation of the pump 4 in one direction, whatever the direction of flow of the fluid in the first 5 and second 6 connections, these hydraulic connections have one (or more) selection valve which makes it possible to direct the hydraulic flow from the pump 4 either to the hydraulic actuator 3 (position A) or to the accumulators 2 (position C) depending on whether the elevator car is to be driven up or down

descent.

  The second hydraulic connection 6 is provided, at a point located between the selection valve 10 and the actuator 3, with a cut-off valve 11 which makes it possible to set or not

  communication of the selection valve 10 with the actuator 3.

  The accumulators 2, the hydraulic pump 4 and the actuator 3 form a pressurized hydraulic circuit in which is transferred, according to the principle of "communicating vessels", a certain amount of fluid contained in the accumulators 2 towards the actuator 3 and vice versa in

  depending on the position to be reached by the cabin.

  In order to avoid overpressures in the circuit, a safety valve 12 is installed on the second hydraulic connection 6, between the selection valve 10 and the pump 4, in order to cause an oil leak in the direction of a reservoir 13 These leaks are directed towards the reservoir 13 by means of a pressure-relief line 14 on which is mounted a non-return valve 15 preventing the

  return of the fluid in the circuit from the reservoir 13.

  Overpressures are for example produced by pcm.pe 4.

  When a certain quantity of leakage oil has accumulated in the reservoir 13, it is possible to return this quantity to the circuit via a return pipe 16 pricked on the second hydraulic connection 6, between the selection valve 10 and the cut-off valve 11. A non-return valve 17 is mounted on this return line 16 preventing the fluid from the circuit from flowing to the reservoir 13. In practice, the oil is returned to the circuit when the reservoir 13 is

practically full.

  In order to cause the elevator car to rise, the selection valve 10 is controlled in position A and the cut-off valve 11 is controlled in the open position. The motor 7 is supplied with electrical energy and causes the pump 4 to rotate. The direction of flow of the fluid in the circuit is made according to the arrows Fm. The oil is sent into the actuator 3 from the accumulators 2. The engine 2 provides very little energy since most of the energy is supplied by the accumulators 2. The energy consumed by the engine 7 is linked only to the role of flow regulator played by the pump 4. When the elevator arrives at a stage D5 preselected by an operator, the motor slows down and the flow of fluid flowing in the circuit decreases to cab stop. This cabin is maintained in position by controlling the selection valve 10 in position B. Even if this selection valve 10 is not controlled in position B and is maintained in position A, the presence of a non-return valve 18 preventing the return of the fluid to the accumulators 2 through the pump 4 ensures the maintenance of the cabin on the predetermined stage. The pumping parts of pump 4 cannot be transformed into a hydraulic motor by turning in one direction

  contrary due to the presence of the anti-diverter unit 8.

  To drive the cabin to another selected stage, the motor 7 is restarted to drive the pump and inject an additional quantity of fluid

in the actuator 3.

  The quantity of fluid contained in the 1 accumulators 2 is at least equal to the quantity of oil necessary to drive the actuator 3 along the length

total of its stroke.

  When the operator wants to control the elevator downhill, the selection valve 10 is controlled in position C and the cut-off valve 11 is kept in the open position. The motor 7 is again supplied with energy and the weight of the cabin causes the fluid to be expelled from the actuator 3 so that the fluid circulates in the arrows Fd and the fluid is returned to the accumulators 2. The speed of descent of the elevator is regulated by the motor 7 which controls the flow of fluid in the circuit. The main amount of energy is supplied by the weight of the downhill cabin, the energy consumed by the engine 7 being simply that necessary for injecting the fluid into the accumulators 2 when the potential energy of the cabin becomes insufficient. to put in

pressure the accumulators 2.

  For safety reasons, a device (not 3 shown in the figures) prohibits the operation of the selection and cut-off valves. In addition, in the event of a broken connection or of a component of the pump, for example, the cut-off valve 11 is diaphragmed to limit the speed of descent of the cabin (which descends under its own weight), and can be closed by a

  electric control at any time.

  To return the fluid contained in the reservoir 13 to the accumulators 2 (quantity of leakage oil detected in the reservoir exceeding a certain threshold), the selection valve 10 is maintained in position C and the cut-off valve 11 is closed. Activation of pump 4

  sucks the fluid towards the accumulators 2.

  It is understood that the hydraulic pump operates in addition to energy when the pressure stored in the accumulators is. lower than that required to operate the actuator or in energy absorption when the pressure stored in the accumulators is higher than that necessary to operate the actuator, thus adapting to the level of the load to be operated, with regard to stored energy. The second embodiment shown in FIG. 2 differs from the first embodiment previously described only by the connection of the hydraulic pump to the accumulators and to the jack. Also, the constituent parts common to the two embodiments will bear

  identical reference numbers.

  -5 D The hydraulic circuit formed by the accumulators 2, the hydraulic pump 4 and the actuator 3 no longer includes a selection valve but four cut-off valves 20 to 23 coupled to four non-return valves 24 to 27, and the pump

  does not have a centerboard.

  The hydraulic pump 4 is connected to the accumulators 2 by a first connection 28 and a second connection 29 which respectively constitute the inlet and the outlet of the

pump 4.

  The first connection 28 is divided into two conduits and 31 connected respectively to the accumulators 2 and to the piston 3. Each of these conduits carries respectively the cut-off valve 20,21 and the non-return valve 24,25 which prevents the flow of the from pump 4 to

accumulators 2 and the piston 3.

  The second connection 29 is divided into two conduits 32 and 33 connected respectively to the accumulators 2 and to the piston 3. Each of these conduits carries

  respectively the cut-off valve 22,23 and the non-return valve

  return 26,27 which prevents the flow of oil from the

  accumulators 2 and the piston 3 towards the pump 4.

  As before, in order to avoid overpressures in the circuit, the overpressure line 14 on which the non-return valve 15 is mounted opens into the reservoir 13 and is connected to the second connection 29 by the safety valve 12. Similarly , the return of the fluid in the circuit is ensured by the return pipe 16 which is

  connected to the first connection 28.

  When the elevator is raised, the cut-off valves 20, 23 are open while the cut-off valves 21, 22 are closed. To obtain the descent of the elevator, the cut-off valves 21, 22 are open while the cut-off valves 20, 23 are closed. The direction of circulation of the fluid in the pump 4 is thus always the same (arrows F) whatever the movement to be given to the elevator. The operation of the device is

  similar to that described above.

  It is understood of course that the device according to the present invention can be used to drive elements other than a piston such as for example a hydraulic motor to move a load and can for example be taken on board an aircraft to cause the climb and the

descent from a landing gear.

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Claims (10)

  1. Hydraulic drive device (1)   and forth from a load subjected to an antagonistic force opposing one of the directions of movement of this load, characterized in that it comprises a hydraulic circuit (1) under pressure comprising: - at least one accumulator d hydraulic power (2) in which a fluid is stored, the pressure of which depends on the quantity of fluid stored; - a hydraulic actuator (3) linked to the load; and - a hydraulic pump (4) which communicates on the one hand with the accumulator (2) and on the other hand with the actuator (3) being interposed between them, the hydraulic pump (4) being adapted to impose a predetermined flow rate of fluid selectively expelled from the accumulator (2) towards the actuator (3) and stored in the accumulator (2) from the actuator (3), respectively during the displacement of the load according to a first direction against the opposing force opposing this movement and when the load returns in the second direction of movement, the volume of fluid stored in the accumulator (2) being at least equal to the volume necessary to move the actuator (3) over its entire travel.   2. Hydraulic device according to claim 1, wherein the pressure and the volume of the fluid stored in the accumulator (2) being adapted so that the load moves by itself in the second direction of movement, the pump (4) being adapted to brake then the transfer of fluid to the accumulator (2).   3. Hydraulic device according to claim 2, in which the hydraulic pump (4) is a unidirectional pump connected to the accumulator (2) e: to the actuator (3) respectively by a first and a second hydraulic connection (5, 6), at least one selection valve (10) being disposed on these two connections (5, 6) to maintain a direction of flow of the fluid in the   pump independent of the direction of movement of the load.   4. Hydraulic device according to claim 3, in which a non-return valve (18) is interposed between the selection valve (10) and the pump (4) to maintain the load in a predetermined position after stopping the pump (4 ). 5. Hydraulic device according to claim 4, in which a relief valve (12) is interposed between the selection valve (10) and the non-return valve (18) to return the fluid to a reservoir (13) during   an overpressure occurring in the circuit (1).   6. Hydraulic device according to claim 5, wherein a pipe (16) connects the reservoir (13) to the second connection (6) to bring the fluid sent into the   tank (13) towards the accumulator (2).   7. Hydraulic device according to claim 6,   in which a non-return valve (17) is mounted on the pipe (16).   8. Hydraulic device according to any one of   Claims 3 to 7, characterized in that the pump   hydraulic (4) comprises a drive motor (7) and pumping component parts, between which is interposed an anti-diverter housing (8) allowing said pumping component parts not to operate as a motor. 9. Hydraulic device according to claim 1 or in which the hydraulic pump (4) is a unidirectional pump connected to the accumulator (2) and to the actuator (3) by first and second hydraulic connections (28, 29) which extend respectively by two conduits (30 to 33) on which are mounted cut-off valves (20 to 23) coupled to non-return valves (24 to 27) so that the pump (4) is unidirectional   whatever the direction of movement of the load.   10. Elevator comprising a cabin on board of which the hydraulic device is installed (1)   drive according to any one of the claims   previous, the hydraulic actuator (3) being constituted   by a jack driving the cabin.