Brake system

Abstract

A brake system (2) for a lift (1) has a brake (6) and a hydraulic system. A method can test a brake system (2). The brake (6) has a spring (5), a main body (16) and a brake element (3). A force is applied to the brake element (3) by a spring (5) such that the brake element (3) is preloaded in the direction of a brake position, and the brake element (3) can be moved by a hydraulic actuator (14) in the direction of a drive position. The hydraulic system has a control device (7), a pump (8), a line (15), a service valve (9), an emergency valve (10) and the actuator (14). The emergency valve (10) is designed to abruptly discharge the hydraulic fluid (11) out of the actuator (14) and thus to abruptly bring the brake system (2) into a brake state. The control device (7) is designed to control the pump (8), the service valve (9) and the emergency valve (10) such that the actuator (14) moves the brake element (3) into a test state, to activate the emergency valve (10) in the test state, and to analyse whether the brake system changed from the test state to the brake state. In the test state, a position of the brake element (3) relative to the main body (16) is substantially the same as the position of the brake element (3) relative to the main body (16) in the brake state. The actuator compensates the force of the spring.

Description

[0001] braking system

[0002] The present invention relates to a braking system, an elevator comprising the braking system and a method for testing the braking system for the elevator.

[0003] In an elevator, a car is typically moved vertically along a travel path between different floors or levels within a building. At least in tall buildings, an elevator type is usually used in which the car is held by rope or belt-like support elements and is moved within a shaft by moving the support elements using a drive machine. The weight of the car is often compensated by a counterweight. Both the car and the counterweight are referred to as the traveling body. The traveling body of an elevator can be equipped with a braking system. A braking system can be hydraulic. The braking system is typically designed such that a spring in a brake of the braking system presses a braking element against a brake rail. The brake rail is usually identical to a guide rail attached to the elevator, which serves to guide the car in the shaft.The spring can press the braking element so tightly against the rail that the vehicle cannot move along the rail. To release the braking system, an actuator counteracts the spring. This ensures that the braking system is considered safe. Even if the actuator or control unit fails, the braking system remains in a braking and therefore safe state.

[0004] A hydraulic braking system has a hydraulic actuator. Hydraulic braking systems therefore have a hydraulic actuator to move the braking element from the safe, braking position to a driving position. The actuator is usually moved by a pump, which pumps hydraulic fluid into the actuator.

[0005] EP 3 145 847 A1 shows a braking system with a hydraulic system. Such a hydraulic system often has two types of valves. A service valve is used to slowly and controlledly drain the hydraulic fluid from the actuator at the end of a journey, so that the braking system closes quietly and in a controlled manner. In an emergency, however, the braking system would close too slowly. Therefore, the systems usually also have an emergency valve that, when activated, suddenly drains the hydraulic fluid from the actuator. This allows the braking system to be closed abruptly in an emergency.

[0006] The service valve is activated regularly during operation. The emergency valve, on the other hand, is activated very rarely. However, it should be tested regularly to ensure it is functioning properly. To do this, the brake system is released and the emergency valve is activated, which, if functioning correctly, causes the brake to close abruptly.

[0007] An alternative test involves wear on the brake element. Wear can reduce the braking force of the braking system. In this case, redundant brakes in a braking system can only be tested individually using redundantly designed emergency valves. Activating a single redundant brake can be used to check whether a single brake can still generate sufficient braking force.

[0008] Activating the emergency valves from the drive position is very loud because the sudden closing of the braking system generates noise. This noise is also transmitted directly into the building structure via the rails, which act as a force. Tests are often automated and performed at night, as the elevator is less used then. Therefore, it's easier to shut down the elevator briefly at night. A loud test can be very disruptive for the building's residents, especially at night.

[0009] It can therefore be seen as a task to minimize the disturbances caused by the elevator.

[0010] According to a first aspect of the invention, a braking system for an elevator solves the problem. The braking system comprises a spring, a base body, and a braking element. The braking element is subjected to a force by a spring, so that the braking element is preloaded toward a braking position. The braking element is movable toward a travel position by a hydraulic actuator. The braking element is guided on the base body. In a braking state of the braking system, the braking element is in the braking position. In a travel state of the braking system, the braking element is in the travel position. The hydraulic system comprises a control device, a pump, a line, an operating valve, an emergency valve, and the actuator, wherein the pump is designed to pump hydraulic fluid through the line into the actuator, and the actuator thereby releases the brake.The operating valve is designed to drain the hydraulic fluid from the actuator in a controlled manner in order to move the braking element into the braking position. The emergency valve is designed to abruptly drain the hydraulic fluid from the actuator, thereby abruptly moving the braking element into the braking position. The control device is designed to control the pump, the operating valve, and the emergency valve so that the actuator brings the braking system into a test state, activates the emergency valve in the test state, and analyzes whether the braking system has changed from the test state to the braking state. In the test state, the position of the braking element relative to the base body is essentially the same as the position of the braking element relative to the base body in the braking state, and the actuator compensates for the force of the spring.

[0011] According to a second aspect of the invention, an elevator solves this problem. The elevator comprises a rail and a traveling body with a braking system according to the first aspect of the invention. The traveling body is guided along the rail.

[0012] In the braking position, the braking element is pressed against the rail. In the driving position, the braking element has a clearance to the rail, and in the test state, the braking element is in contact with the rail with essentially no force.

[0013] According to a third aspect of the invention, a method for testing a braking system for an elevator solves the problem. The braking system has a brake and a hydraulic system. The braking system has a spring, a base body, and a braking element. The braking element is subjected to a force by a spring, so that the braking element is preloaded towards a braking position. The braking element is movable towards a driving position by a hydraulic actuator. The braking element is guided on the base body. In a braking state of the braking system (2), the braking element (3) is in the braking position, and in a driving state of the braking system (2), the braking element (3) is in the driving position. The hydraulic system has a control device, a pump, a line, an operating valve, an emergency valve, and the actuator. The pump is designed to pump hydraulic fluid into the actuator. The actuator thereby releases the brake.The operating valve is designed to drain the hydraulic fluid from the actuator in a controlled manner, thereby shifting the braking element into the braking position. The emergency valve is designed to abruptly drain the hydraulic fluid from the actuator, thereby abruptly shifting the braking element into the braking position. The control device controls the pump, the operating valve, and the emergency valve. The method comprises the following steps:

[0014] -bringing the braking system into a test condition, -activating the emergency valve, and

[0015] - Analyze whether the braking system has been changed from the test state to the braking state,

[0016] In the test condition, the braking element essentially rests against the rail, and the actuator essentially compensates for the force of the spring.

[0017] Possible features and advantages of embodiments of the invention may be considered, among other things and without limiting the invention, to be based on ideas and findings described below.

[0018] As already described in the introduction, a traveling body can be designed either as a cabin or as a counterweight. On traveling bodies, two brakes are typically mounted on opposite sides of the traveling body. The brakes interact with the guide rails on which the corresponding traveling body is guided to brake. This means that a braking element is pressed onto a surface of the rail from at least one side when braking. This generates a frictional force which acts as a braking force. The braking element can have a brake pad for this purpose. Alternatively, the braking element can be pressed directly onto the rail. A counter element is preferably arranged on the side of the rail opposite the braking element. The counter element preferably delivers a force to the rail that is opposite to the normal force of the braking element. The counter element can be designed as a movable counter element.Alternatively, the counter element can be firmly connected to the base body.

[0019] The braking element is subjected to a force by a spring such that it is preloaded toward the braking position, i.e., toward the rail. The spring force is set so that the normal force exerted by the spring in the braking state produces the braking force, and this braking force is sufficiently large to hold the vehicle securely to the rail. The spring can be designed as a coil spring, a disc spring assembly, or a C-spring that essentially encloses the brake.

[0020] In the test condition, the braking element is essentially in the same position relative to the base body. However, in the test condition, the braking element exerts a virtually negligible normal force on the rail. In the test condition, the brake essentially exerts no braking force. This distinguishes the test condition from the braking condition, in which the braking system essentially exerts a sufficiently large braking force.

[0021] The difference between the braking condition and the test condition is that the pressure of the hydraulic fluid in the test condition is essentially the same as the ambient pressure.

[0022] The braking element can be moved into the driving position by a hydraulic actuator, which is designed as a hydraulic cylinder. The actuator is part of the hydraulic system, which further comprises a control device, a pump, an operating valve, and an emergency valve. The pump can pump hydraulic fluid from a reservoir into the actuator via a hydraulic line. The pump is preferably designed so that it can pump the hydraulic fluid towards the actuator and act as a shut-off valve in the opposite direction. The pump is preferably driven by an electric motor. The operating valve and the emergency valve are arranged on the line connecting the pump to the actuator so that these valves can drain the hydraulic fluid from the actuator. The drained hydraulic fluid is fed back into the reservoir. The operating valve has a throttle that allows only a small flow rate.Activating the service valve causes the braking system to close so slowly that the braking element touches the rail almost silently. This movement can take 1 to 10 seconds from the running position to the braking position. In an emergency, such a slow application of the brake would take too long. The emergency valve allows a flow rate so large that the braking system can close from the running position to the braking position in less than one second, preferably less than 0.1 s.

[0023] The test condition is characterized by the braking element essentially just touching the rail, while exerting a negligible or insignificantly small normal force on the rail. In the test condition, the braking system therefore exerts a negligible braking force. In the test condition, the distance between the braking element and the rail can also be negligible, causing the braking force to disappear completely. The advantage of the test condition is that when the emergency valve is opened in the test condition, the braking element, because it touches the rail immediately after the emergency valve is activated, cannot reach a sufficiently high speed to generate a loud noise when it hits the rail. When the emergency valve is activated in the running position, a large part of the potential energy stored in the spring is converted into kinetic energy of the braking element.Therefore, in this case, the braking element hits the rail at high speed, creating a bang. Starting from the test condition, the movement of the bogie changes from essentially free to fully braked in the braking condition, provided the emergency valve test is successful. A test of the emergency valve or a test to determine whether the braking force is still sufficient can therefore be carried out essentially silently.

[0024] The difference between the braking state and the test state is that the hydraulic fluid pressure in the actuator in the test state essentially corresponds to the hydraulic fluid pressure in the drive position. In the braking position, the hydraulic fluid pressure in the actuator essentially corresponds to the ambient pressure, or in other words, the actuator is pressure-free in the braking position.

[0025] The control device controls the pump, the operating valve, and the emergency valve, preferably via electrical signals. For this purpose, the control device is preferably designed as an electronic component, for example, preferably as a control computer. The control device controls, in particular, the individual steps of the method, i.e., moving the braking element in the test state, activating the emergency valve, and analyzing whether the braking element has changed from the test state to the braking state. In one embodiment of the method, the pump can be activated from the braking state until the actuator pushes the braking element away from the rail. In this case, movement of the traveling body can be detected. The pump can, for example, also be operated very slowly. If movement of the traveling body is detected, the emergency valve can be activated.A functioning emergency valve will brake the vehicle again. If the emergency valve is not functioning, the vehicle will continue to move. In this case, the operating valve is preferably activated to close the braking system and still stop the vehicle.

[0026] In the test state and in the braking position, the braking element essentially rests against the rail. This essentially means that the position of the braking element relative to the base body in the test state is essentially the same as the position of the braking element relative to the base body in the braking position. Within the scope of this definition, the braking element can have a vanishingly small distance from the rail in the test state. This vanishingly small distance is much smaller than the clearance, i.e., at least by a factor of 10.

[0027] According to one embodiment, the control device is designed to control the pump such that the pump is activated for a predefined period of time in order to move the braking system from the braking state to the test state.

[0028] This allows for a particularly simple design of the braking system. The braking system can thus be implemented cost-effectively and, in particular, without the need for additional sensors.

[0029] According to a preferred embodiment, when the braking system is brought into a test state, the pump is controlled such that the braking system is brought from the braking state into the test state. This means that the method can begin from the braking position. Alternatively, the test state could be reached from the driving position by activating the operating valve, for example, for a predefined time.

[0030] According to a preferred embodiment, when bringing the braking system into the test state, the pump is switched on for a predefined duration in order to move the braking system from the braking state into the test state.

[0031] The predefined time period can be fixed or determined during elevator installation. The predefined time period is easily implemented using a control device, and no additional sensors are required.

[0032] By activating the pump, the pressure in the actuator can be increased to such an extent that the force of the spring is compensated, and thus there is essentially no braking force left.

[0033] Alternatively, it would be possible, for example, to start from the driving state. To do this, starting from the driving position of the driving state, the operating valve would release enough hydraulic fluid until the test position of the brake element, and thus the test state, is reached.

[0034] According to a further embodiment, the method may comprise the step of, after activation of the emergency valve, a main drive of the elevator exerting a force on the traveling body, measuring the resistance of the traveling body to this force, and analyzing whether the braking system has been brought from the test state to the braking state, determining whether the emergency valve is functioning correctly from the measured resistance. If the traveling body offers significant resistance to movement, then the emergency valve has functioned. If the traveling body offers insignificant resistance to movement, then the emergency valve has not functioned. The position of the traveling body can be obtained using a known shaft information system that determines the speed and / or position of the traveling body. The force that counteracts a displacement of the traveling body can be determined by the motor control.This also makes it possible to determine the exact braking force of the brake and to decide whether it still achieves a minimum braking force.

[0035] Preferably, the main drive holds the car at the same height in the shaft during the test. This ensures that the car remains in the same position after the test as before. After activating the emergency valve, the drive torque of the main drive can be reduced. If the car does not move, the emergency valve test was successful.

[0036] This process step—i.e., applying a force to the vehicle with the main drive and measuring the vehicle's resistance to this force—is preferably performed once the test condition has been reached by activating the pump for a predefined period of time. This process step can also be performed without additional sensors on the braking system. Thus, this process allows for a cost-effective design of the braking system without additional sensors.

[0037] According to a preferred embodiment, the hydraulic system has a pressure sensor that measures a pressure of the hydraulic fluid in the actuator.

[0038] The pressure sensor can measure the pressure directly in the actuator cylinder, on the pump, on the line from the pump to the actuator, or on another line connected to this line. The pressure sensor can therefore also be installed, for example, on the service valve or the emergency valve. The pressure is lowest when braking. The pressure initially increases relatively quickly due to pumping, while the normal force between the braking element and the rail decreases, although the braking element essentially does not yet move. As soon as the braking element moves, the pressure increases much more slowly. In this range, the pressure depends essentially on the spring force, which typically increases with increasing deformation of the spring.

[0039] According to a preferred embodiment, the hydraulic system has a pressure sensor that measures the pressure of the hydraulic fluid in the actuator. When the brake system is brought into the test state, the pressure sensor detects the pressure in the actuator. If a limit pressure is exceeded, the test state is considered to have been reached. This signal that the test state has been reached can be used to deactivate the pump. In principle, it is sufficient for the pressure sensor to detect that the limit pressure has been exceeded. The pressure sensor can therefore be designed such that a switch is activated when the limit pressure is reached, and the activation of the switch is preferably evaluated by the control device. According to one possible embodiment, the pressure sensor detects a first pressure in the actuator before the emergency valve is activated. The pressure sensor detects a second pressure in the actuator after the emergency valve is activated.The control device determines whether the emergency valve is functioning correctly based on the first pressure and the second pressure in a subsequent step.

[0040] In a cost-effective design, the pressure sensor can be configured as a switch. When the limit pressure is exceeded, the pump is deactivated and the emergency valve is activated. The first pressure exceeds the limit pressure. After the emergency valve is activated, the control device, for example, can check whether the limit pressure is still exceeded. If the limit pressure is still exceeded, the emergency valve is considered defective. If the emergency valve is functioning correctly, the pressure should have fallen below the limit pressure.

[0041] Alternatively, a pressure sensor can be used to determine the current pressure, i.e., a measured value determined by the pressure sensor that includes the current pressure. Based on the pressure from the sensor, which is preferably supplied essentially continuously to the control unit, the control unit can control the activation of the emergency valve. For example, the control unit can determine when the braking system reaches the test state based on the exact progression of the pressure increase. This is the moment at which the pressure increase in the actuator slows down significantly, as the braking element loses contact with the rail and is now moved against the essentially constant force of the spring. This allows the control unit to independently set the limit pressure or directly activate the emergency valve without explicitly determining a limit pressure. Recording the continuous pressure values ​​also allows for more precise evaluation of the emergency valve test.For this purpose, the control device can evaluate how quickly the pressure changes, i.e. the pressure change per time over a short period of time, or how long it takes from activation to a complete drop in pressure or alternatively to a certain pressure.

[0042] According to a further embodiment, the braking system has a position sensor that detects when the test state is reached.

[0043] Such a position sensor can be configured, for example, as a switch that can measure the position of the braking element in one direction relative to the rail or relative to a housing of the braking system. The switch is calibrated to switch when the test condition is reached. The test condition is preferably reached starting from the driving condition.

[0044] Preferably, the position sensor resolves the position of the braking element between the braking position and the driving position essentially continuously. Continuous resolution is achieved when this distance is divided into at least 10 sub-distances. Typical position sensors can typically divide such distances into 1024 or more sub-distances.

[0045] According to a preferred embodiment, the braking system has a position sensor that detects when the test state is reached. When the braking system is brought into the test state, the position sensor detects the position of the braking element relative to the rail. When a limit position is exceeded, the test state is considered reached. A signal indicating that the test state has been reached can be used to deactivate the pump.

[0046] The position sensor can therefore directly detect when the test state has been reached. For this purpose, the position sensor can be designed as a switch that switches when the test state is reached. This switch preferably has a hysteresis to prevent an undesirable accumulation of switching operations when the test state is reached.

[0047] The position sensor can, for example, measure the relative position of the braking element to the rail. The position sensor can also measure, for example, the relative position between the braking element and the base body or between the braking element and the running body. The position sensor then determines a position signal. The position signal can contain only the information "before the limit position" or "after the limit position" in binary form. Alternatively, it can also contain the exact position of the braking element with essentially continuous resolution. This position signal can then be transmitted to the control unit as a voltage value or as a digital signal. The control unit evaluates the position signal and detects, for example, based on the limit position being exceeded, that the test condition has been reached.

[0048] According to a preferred embodiment, the brake has a force sensor that measures a normal force on the braking element. When the braking system is brought into the test state, and the normal force drops to zero, the test state is considered reached. A signal indicating that the test state has been reached can be used to deactivate the pump.

[0049] The force sensor is preferably mounted on the base body. In an advantageous embodiment, the force sensor can measure the force exerted by the counter element on the base body. Alternatively, the force sensor can also be mounted between the braking element and the actuator, or between the actuator and the base body.

[0050] According to a preferred embodiment 14, the pressure sensor, the position sensor, or the force sensor (19) determines a first measured value before the emergency valve is activated, and the pressure sensor, the position sensor, or the force sensor determines a second measured value after the emergency valve is activated. The control device determines, based on the first measured value and the second measured value, whether the emergency valve is functioning correctly.

[0051] According to a preferred embodiment, the control device is designed such that a first sensor measured value of the pressure sensor, the force sensor or the position sensor can be determined before the activation of the emergency valve, and such that a second sensor measured value of the pressure sensor, the force sensor or the position sensor can be determined after the activation of the emergency valve, and to compare the first sensor measured value with the second sensor measured value in order to analyze whether the braking system has changed from the test state to the braking state.

[0052] This makes it possible to analyze with a single sensor whether the braking system has switched from the test state to the braking position. This also determines whether the emergency valve has functioned correctly. Only if the emergency valve has been triggered correctly does the braking system switch from the test state to the braking state. Further advantages, features, and details of the invention will become apparent from the following description of exemplary embodiments and from the drawings, in which identical or functionally equivalent elements are provided with identical reference numerals.

[0053] Showing:

[0054] Fig. 1 the brake system with a pressure sensor,

[0055] Fig. 2 the braking system with a position sensor,

[0056] Fig. 3 the braking system with a force sensor,

[0057] Fig. 4 an alternative braking system with two brakes,

[0058] Fig. 5a a brake in braking state

[0059] Fig. 5b the brake in test condition,

[0060] Fig. 5c the brake in driving condition,

[0061] Fig. 6 an elevator with the braking system,

[0062] Fig. 7 a method

[0063] Fig. 1, Fig. 2, and Fig. 3 show a braking system 2. The braking system 2 comprises a braking element 3 and a hydraulic system. The braking element 3 is designed to exert a contact force on the rail 20 by pressing it against the rail 20. For this purpose, the braking system 3 has a spring 5 that applies a force to the braking element 3 such that it is preloaded toward a braking position. In the braking position, the contact force is sufficiently large to generate a sufficiently large braking force.

[0064] To release the brake 6, the braking system 2 has an actuator 14 designed to lift the braking element 3 from the rail 20 against the force applied by the spring 5. When the braking element 3 is lifted from the rail, a clearance is created between the rail 20 and the braking element 3. The braking system 2 has a brake 6. The brake 6 comprises the braking element 3, the spring 5, the actuator 14, and a counter element 16 and a base body 16 on which the braking element 3, the spring 5, the actuator 14, and the counter element 16 are arranged. The base body 16 serves to attach the brake 6 to a traveling body 16 and to transmit the braking force to the traveling body. The counter element 17 is designed to generate a counter force to the contact pressure on a side of the rail 20 opposite the braking element 3 in the braking state.The braking element 7 and / or the counter element 17 can have a brake pad that is brought into contact with the rail 20. Alternatively, the braking element 7 and / or the counter element 17 can also be brought into direct contact with the rail 20.

[0065] The actuator 14 is part of the hydraulic system, which further includes a control device 7, a pump 8, an operating valve 9, and an emergency valve 10. The actuator 14 is preferably designed as a single-acting hydraulic cylinder. By building up hydraulic pressure in the actuator, the actuator 14 acts against the spring 5, thereby releasing the brake 6.

[0066] A line 15 leads from a pump 8 to the actuator 14. The pump 8 can increase the pressure in the actuator when it is switched on. This allows the brake 6 to be released. To close the brake 6, the operating valve 9 and the emergency valve 10 are connected to the line. Both valves serve to drain a hydraulic fluid 11 from the line 5 and thus also from the actuator 14, in order to close the brake 6. The operating valve 9 has a high internal resistance, which can be caused, for example, by an orifice, which causes the hydraulic fluid to be drained from the actuator 14 so slowly that the braking element 3 moves slowly and silently against the rail 20 and is pressed against it. However, this closing process would be too slow for an emergency.Therefore, the emergency valve 10 is designed to drain the hydraulic fluid 11 from the actuator 14 so quickly that the brake element 3 moves to the rail 20 essentially suddenly, for example in less than 1 s and more preferably in less than 0.1 s, and the brake 6 is thereby closed.

[0067] Pump 8, operating valve 9, and emergency valve 10 are controlled by control device 7. During normal operation, control device 7 activates pump 8 to release brake 6 by pumping hydraulic fluid 11 into line 15 and thus actuator 14. While driving, pump 8 can remain activated, particularly if it has an overflow valve, or it can be deactivated. To apply the brake during normal operation, pump 8 is preferably deactivated.

[0068] Fig. 1 shows a braking system with a pressure sensor 12. The pressure sensor 12 measures the hydraulic pressure of the hydraulic fluid. The pressure in the actuator 14 is essentially identical to the pressure throughout the line 15. The pressure sensor can therefore be connected to any point on the line 15. When the braking system is closed, the pressure in the line 15 essentially corresponds to the ambient pressure. To release the brake, and thus the braking system 2, the operating valve 9 and the emergency valve 10 are closed, and the pump 8 is switched on. The pressure initially increases rapidly until the force of the actuator reaches the preload force of the spring 5. As the pressure in the actuator increases, the braking force decreases and disappears when the force of the actuator 14 reaches the preload force of the spring 5. The actuator 14 then moves, thereby tensioning the spring 5. The pressure only increases slightly.

[0069] The pressure sensor 7 is connected to the control device 7. The pressure sensor 12 can be designed such that the pressure sensor 12 provides the control device 7 with a binary signal. The pressure sensor 12 can therefore function like a switch that switches at a limit pressure. The limit pressure is preferably at or slightly above the pressure at which the force of the actuator 14 reaches the preload force of the spring 5. Preferably, however, the pressure sensor 12 provides continuous and high-resolution pressure values. This allows the control device 7 to determine from the course of the pressure curve at which pressure the force of the actuator 14 reaches the preload force of the spring 5. This makes it possible to check with each release whether the stored limit pressure is still correct or whether the limit pressure needs to be adjusted, for example due to abrasion.

[0070] Fig. 2 shows a braking system 2 with a position sensor 13. The position sensor is connected to the control unit 7. When the braking system is opened, the braking element 3 does not initially move. Only when the pressure in the actuator 14 becomes large enough so that the force of the actuator exceeds the preload force of the spring 5 does the braking element 3 begin to move. The position sensor 13 can be designed such that the position sensor 13 provides the control device 7 with a binary signal. The position sensor 13 can therefore function like a switch that switches when a limit position of the braking element 3 is reached. The limit position is preferably at a position at which just a minimal play is reached between the braking element 3 and the rail 20. However, the position sensor 13 preferably provides continuous and high-resolution position values, for example in steps of millimeters or tenths of a millimeter.This allows the control device to determine from the transmitted position data exactly when the braking element has a minimum play with respect to the rail 20.

[0071] Fig. 3 shows a braking system with a force sensor 19. The force sensor is connected to the control unit 7. The force sensor 19 is mounted between the counter element 17 and the base body so that it can measure the force that the counter element 19 exerts on the rail 20. Since the force sensor 19 directly measures the normal force of the brake 6, the force sensor can directly determine whether or not a normal force is present. The force sensor can be designed as a switch that switches a binary signal for the control device 7 at a preferably minimal limit force. Preferably, however, the force sensor 19 provides continuous and high-resolution force values, for example, in steps of individual N or 100 N. Typical force sensors use piezoelectric materials or strain gauges.

[0072] Fig. 4 shows a further embodiment of a braking system 2. Here, a first brake 6a and a second brake 6b are supplied with hydraulic fluid 11 by a common pump 8. The operating valve 9 is connected to the brakes in such a way that activation of the operating valve always closes both brakes 6a and 6b together. The braking system has a first emergency valve 10a and a second emergency valve 10b. The first emergency valve 10a can release the actuator of the first brake 6a, and the second emergency valve 10b can release the actuator of the second brake 6b. The braking system 2 therefore has redundant emergency valves 10a and 10b. Between the pump 8 and the first brake 10a there is a check valve 23 which prevents hydraulic fluid from flowing from the first brake into the second brake.Between the first brake 6a and the operating valve 9 is another check valve 23, which prevents hydraulic fluid 11 from flowing from the first brake 6a into the second brake 6b. Similar check valves 23 are installed for the second brake 10b, which similarly prevent hydraulic fluid from flowing from the brake 6b into the brake 6a. It is therefore possible, for example, to close only the brake 6a and leave the brake 6b open for a test. For this purpose, the emergency valve 10a must be activated. It is advantageous to use the method according to the invention to ensure that the closing process is as quiet as possible.

[0073] Figures 5a, 5b, and 5c each show only a section of the braking system, namely the brake 6. A base body 16 holds the counter element 17 and the braking element 3. The braking element 3 is movably mounted on the base body 16. The spring 5 presses the braking element 3 toward the rail 20. The actuator 14 is designed as a hydraulic cylinder sealed by seals 18. The actuator 14 can be displaced by the incoming or outgoing hydraulic fluid 11.

[0074] Figure 5a shows brake 6 of braking system 2 in the braking state. In this state, the pressure in the line and in the actuator is essentially identical to the ambient pressure, and the braking system brakes with the maximum possible force. The pressure in actuator 14 in the braking state corresponds to the minimum pressure that can typically occur in actuator 14 during operation. The braking element 3 and the counter element 17 press against the rail 20 with the maximum normal force. Thus, brake 6 brakes.

[0075] Fig. 5c shows the driving state of brake 6 of braking system 2. The braking element 3 and the counter element 17 do not touch the rail 20. There is sufficient clearance between the rail 20 and all components of braking system 2 so that the brake 3, and in particular the braking element 3 and the counter element 17, does not touch the rail 20 during driving. There is now more hydraulic fluid in the actuator 14, and the hydraulic fluid has spaced the braking element 3 from the rail. The pressure in the actuator 14, during the driving position, corresponds to the maximum pressure that can typically occur in the actuator 14 during operation.

[0076] Fig. 5b shows the test state of the brake ö of the braking system 2. Here, the braking element 3 is essentially in the same position as in the braking state of Fig. 5a. The difference is that there is essentially no contact force between the braking element 3 and the rail 20. In this state, the braking system therefore delivers essentially a negligible braking force. However, since the braking element is at a negligible distance from the rail, the braking element 3 cannot build up much speed when closing, and the closing process is essentially silent. In the test state, the pressure in the actuator 14 is lower than the maximum pressure that can typically occur in the actuator during operation, but significantly greater than in the braking state. It is therefore significantly closer to the maximum pressure than the minimum pressure that can occur in the actuator 14.

[0077] Fig. 6 schematically shows an elevator 1 with a braking system. The braking system is preferably mounted on the traveling body 21. Only the brake 6 of the braking system is shown. An elevator has two brakes 6, each of which can be activated on one of the two rails 20. The braking system can have only one control device and one pump. Alternatively, the braking system can also have two pumps, for example. The braking system can also be completely redundant and thus also have two control devices.

[0078] The carriage 21 is guided along the rail 20 by guide shoes 31. The main drive 22 moves the carriage along the rails 20. It can also be used to hold the carriage if the brake 6 is in the test state. Alternatively, the main drive can determine whether the brake 6 is closed after testing the emergency valve by measuring the drive force or torque. If the main drive 22 fails, the braking system can hold the carriage 21 to the rails 20.

[0079] Fig. 7 shows exemplary steps of the method. In a first step 41, the braking element is placed in a test state, which is between the braking position and the driving position. In a second step 42, the emergency valve is activated to test the emergency valve. And in a third step, the control device can determine whether the emergency valve is functioning correctly. In an optional third step 43, it is determined whether the emergency valve is functioning correctly.

[0080] The above-described invention thus allows nighttime, preferably automated, tests on an elevator system, which involve activating the emergency valve, to be carried out quietly. This reduces disturbance to the building's residents.

[0081] Finally, it should be noted that terms such as "having," "comprising," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered as limitations.

Claims

Patent claims 1. A braking system (2) for an elevator (1), comprising a brake (6) and a hydraulic system. The brake (6) has a spring (5), a base body (16), and a braking element (3). The braking element (3) is subjected to a force by a spring (5) such that the braking element (3) is pretensioned toward a braking position, and the braking element (3) is movable toward a travel position by a hydraulic actuator (14). The braking element (3) is guided on the base body (16). In a braking state of the braking system (2), the braking element (3) is in the braking position, and in a travel state of the braking system (2), the braking element (3) is in the travel position. The hydraulic system has a control device (7), a pump (8), a line (15), an operating valve (9), an emergency valve (10), and the actuator (14). The pump (8) is designed to supply a hydraulic fluid. (11) through the line (15) into the actuator (14),and the actuator (14) thereby releases the brake (2), the operating valve (9) is designed to drain the hydraulic fluid (11) from the actuator (14) in a controlled manner in order to displace the braking element (3) into the braking position, the emergency valve (10) is designed to drain the hydraulic fluid (11) abruptly from the actuator (14) and thereby abruptly displace the braking element (3) into the braking position, and the control device (7) is designed to control the pump (8), the operating valve (9), and the emergency valve (10) such that the actuator (14) brings the braking system (2) into a test state, to activate the emergency valve (10) in the test state, and to analyze whether the braking system (2) has changed from the test state to the braking state, characterized in that in the test state, a position of the braking element (3) relative to the base body (16) is substantially the same as the position of the braking element (3) relative to the base body (16) in the braking state,and that the actuator compensates for the force of the spring.

2. Brake system (2) according to claim 1, characterized in that the control device (7) is designed to control the pump (8) such that the pump (8) is activated for a predefined period of time in order to change the brake system (2) from the braking state to the test state.

3. Brake system (2) according to one of the preceding claims, characterized in that the hydraulic system has a pressure sensor (12) which measures a pressure of the hydraulic fluid (11) in the actuator (14).

4. Braking system (2) according to one of the preceding claims, characterized in that the brake has a force sensor (19) which measures the normal force acting on the braking element.

5. Braking system (2) according to one of the preceding claims, characterized in that the braking system has a position sensor (13) which detects when the test state is reached.

6. Braking system (2) according to one of claims 3 to 5, characterized in that the control device (7) is designed such that a first sensor measurement value of the pressure sensor (12), the force sensor (19) or the position sensor (13) can be determined before the activation of the emergency valve, and that a second sensor measurement value of the pressure sensor (12), the force sensor (19) or the position sensor (13) can be determined after the activation of the emergency valve, and to compare the first sensor measurement value with the second sensor measurement value in order to analyze whether the braking element has changed from the test state to the braking state.

7. Elevator (1) comprising a rail (20) and a traveling body (21) with a braking system (2) according to one of the preceding claims, wherein the traveling body (21) is guided along the rail (20), and in the braking position the braking element (3) is pressed against the rail (20), in the traveling position the braking element (3) has a clearance to the rail (20), and in the test state the braking element (3) touches the rail (20) essentially without force. - TI - 8. A method for testing a braking system (2) for an elevator (1), wherein the braking system (2) comprises a brake (6) and a hydraulic system, the brake (6) comprises a spring (5), a base body (16) and a braking element (3), the braking element (3) is subjected to a force by a spring (5) such that the braking element (3) is pretensioned towards a braking position, and the braking element (3) is movable towards a travel position by a hydraulic actuator (14), the braking element (3) is guided on the base body (16), in a braking state of the braking system (2) the braking element (3) is in the braking position and in a travel state of the braking system (2) the braking element (3) is in the travel position, the hydraulic system comprises a control device (7), a pump (8), a line (15), an operating valve (9), an emergency valve (10) and the actuator (14), wherein the pump (8) is designed to pump a hydraulic fluid (11) into the actuator (14),and the actuator (14) thereby releases the brake (2), the operating valve (9) is designed to drain the hydraulic fluid (11) from the actuator (14) in a controlled manner and thereby move the braking element (3) into the braking position, the emergency valve (10) is designed to drain the hydraulic fluid (11) suddenly from the actuator (14) and thereby move the braking element (3) suddenly into the braking position, and the control device (7) controls the pump (8), the operating valve (9) and the emergency valve, the method comprising the steps: - Bringing the braking system (2) into a test state, - Activate the emergency valve (10) and - Analyzing whether the braking system (2) has been changed from the test state to the braking state, characterized in that, in the test state, the braking element (3) substantially bears against the rail and that the actuator substantially compensates for the force of the spring.

9. Method according to claim 8, characterized in that - when the braking system (2) is brought into a test state, the pump (8) is controlled in such a way that the braking system (2) is brought from the braking state into the test state.

10. Method according to claim 8 or 9, characterized in that - when bringing the braking system (2) into the test state, the pump (8) is switched on for a predefined period in order to move the braking system (2) from the braking state into the test state.

11. Method according to claim 8 to 10, characterized in that the hydraulic system has a pressure sensor (12) which measures a pressure of the hydraulic fluid (11) in the actuator (14), and - when the brake system (2) is brought into the test state, the pressure sensor (12) detects the pressure in the actuator (14), and when a limit pressure is exceeded, the test state is considered to have been reached.

12. Method according to one of claims 8 to 11, characterized in that the braking system has a position sensor (13) which detects the reaching of the test state, and - when the braking system (2) is brought into the test state, the position sensor (13) detects the position of the braking element (3) relative to the rail (20) or the base body (16), and when a limit position is exceeded, the test state is considered to have been reached.

13. Method according to one of claims 8 to 12, characterized in that the hydraulic system has a force sensor (19) which measures a normal force on the braking element (3), and - when the braking system (2) is brought into the test condition and the normal force drops to zero, the test condition is deemed to have been reached.

14. Method according to one of claims 11 to 13, characterized in that the pressure sensor (12), the position sensor (13) or the force sensor (19) determines a first measured value before the activation of the emergency valve and the pressure sensor (12), the position sensor (13) or the force sensor (19) determines a second measured value after the activation of the emergency valve and the control device (7) based on the first measured value and the second measured value determines whether the emergency valve (10) is functioning correctly.

15. Method according to one of claims 8 to 14, characterized in that - after activation of the emergency valve, a main drive (22) of the elevator (1) causes a force on the traveling body (21) and the resistance of the traveling body (21) against this movement is measured and from the measured resistance, analyzing whether the braking system (2) has been brought from the test state into the braking state, it is decided whether the emergency valve (10) is functioning correctly.

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