FI119727B - Method and system for testing the condition of the brakes for a lift machine - Google Patents

Description

METHOD AND SYSTEM FOR TESTING THE CONDITION OF THE LIFT MACHINE BRAKES

FIELD OF THE INVENTION

The present invention relates to testing the condition of elevator-5 brakes.

BACKGROUND OF THE INVENTION

In lift systems, it is important to seek to maximize passenger safety. The elevator car must not move freely and its movement must not achieve uncontrolled acceleration of movement and subsequent uncontrolled deceleration of movement. Sudden stops with even relatively low kinetic energy can cause injuries to passengers.

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Figure 1 shows a simplified traction sheave apparatus of the prior art and related general safety devices of the prior art. The elevator system consists of a main parts of the elevator shaft 20 100, in passing from the elevator car 102, the elevator car connected to hoisting ropes 116-120, the traction sheave 106 and the counterweight 104. The counterweight is preferably dimensioned to match the weight of the elevator car 102, the weight and the associated body of the mechanics of weight 25, and half of the nominal weight. Nominal load refers to the load carried in an elevator car. In this case, the maximum weight difference between the sides of the elevator car and the counterweight is half the nominal load. Elevator passages 122 and 124, 30 of which preferably are two, run on the sides of the elevator shaft. The purpose of the elevator rails is to hold the elevator car in position on its track in front and rear with respect to the counterweight. In the figure, the elevator car engages grippers 154-156 which brake by gripping the elevator rails 122 and 124. The drive wheel 35 106 is connected to a transmission 107 by an axis 107, which may also include a transmission. The drive means 2 is connected to the motor 110 by an axis 108. The motor 110 is controlled by a control unit 114 via a control cable 112. The engine can be single, dual or variable speed.

5 The torque of the variable speed motor can be infinitely controlled from the control unit 114. The control unit can continuously control the motor torque by means of, for example, control based on alternating voltage and variable frequency. Systems associated with control unit 114 10 for handling basket calls and wrestling control. Brakes 160-162 associated with shaft 108 including brake drums for braking shaft 108. Brakes 160-162 are connected to control unit 114 via a control cable 111. The drive wheel 15 is coupled with a motion measuring device 115, such as a tachometer. The motion measuring device 115 is connected to the control unit via a cable 116.

The authorities of different countries have different regulations regarding the safety of lifts. The basic principle is that the elevator brake system should be able to stop the elevator car at its nominal speed and hold it on the floor, even in the event of overloading the elevator car. The braking system must be fault-tolerant so that a single mechanical failure does not render the braking system completely inoperative.

According to European Safety Order EN81-1: 1998, the brake must be mechanically doubled so that if one of the parts fails, the other half of the brake will still work. The mechanically doubled brake shall stop 125% of the load at the nominal speed. Nominal speed refers to the maximum lift car movement speed that can be achieved by the motor of the machine. One part is a failure at the remaining side alone be able to stop the downward running at rated speed of 100% load. In European elevator equipment 3, the double brake is used in normal operation so that both brakes are always applied simultaneously. The problem with this solution is that the mechanical failure of the second brake may not be noticed. In this way, the elevator may operate for a very long time with only one brake on, and this may result in hazards before the fault is detected and repaired by periodic inspection or other maintenance.

10 In accordance with US Safety Standard A17.1-2000 and Canadian Safety Standard B44-2000, the lift must have one driving machine brake and one emergency brake. In some embodiments, the emergency brake is provided by the grippers 154 and 156 of Figure 1. 15 The mechanical brake should hold the elevator in place with a load of 125%. The emergency brake should stop the elevator at 125% load at low speed. In American elevator equipment, when the normal brake fails, the emergency brake should stop the elevator within a specified distance so that the controlled 20 tonne elevator car acceleration is prevented. The problem with this solution is that the emergency brake is not activated until high speed or acceleration has been achieved and a hazard has occurred. The emergency brake seeks to prevent a passenger from dying, but cannot prevent 25 passengers from tipping over or injuring themselves. In addition, the problem with the emergency brake solution is the complexity of the system due to the extra brake.

JP 10-17246 A discloses a method for testing the condition of an elevator 30 by closing the elevator brake, increasing the torque on the brake, registering a first torque sliding the brake and comparing said torque with a predetermined torque required by the elevator brake. If the first torque of the en-35 is less than the required torque, the brake is worn.

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JP 1-288590 A discloses a method for testing the condition of an elevator brake, which method applies a torque to the brake during the elevator standstill and generates a brake failure signal if a motion detecting signal is obtained from a rotation detector.

PURPOSE OF THE INVENTION

The object of the present invention is to ensure the operation of the brakes of the elevator system and to seek to ensure that the brakes also comply with the above safety regulations between periodic inspections of the elevator system.

With respect to the features of the present invention, reference is made to claims 1 and 9. Other embodiments of the invention are characterized in what is set forth in the other claims. Inventive embodiments are also disclosed in the specification of this application. The inventive content contained in the application may also be defined otherwise than as set forth in the claims below. The inventive content can also consist of several separate inventions, especially if the invention is considered in light of tastes or implicit subtasks, or in terms of the benefits or groups of benefits achieved. In this case, some of the attributes contained in the claims below may be redundant for individual inventive ideas.

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SUMMARY OF THE INVENTION

The invention relates to a method for testing the condition of elevator machinery brakes. The elevator 35 of the invention has two brakes, the first and the second brake. The method involves closing the first brake and 5 opening the second brake; increasing the torque applied to the first brake; recording the first torque at which the first brake slips; defining a second torque required for said first 5 brake; comparing said first torque of the first brake to said second torque of the first brake; if the first torque of said first brake is found to be below said second torque of the first brake, detecting the first 10 brake; closing the second brake and opening the first brake; increasing the torque applied to the second brake; recording the first torque at which the second brake slips; defining a second torque required for said second brake; 15 comparing said first torque of the second brake to said second torque of the second brake; and if it is found that the first torque of said second brake is below said second torque of the second brake, the second brake is detected as worn.

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The invention also relates to a system for testing the condition of elevator machinery brakes. The elevator has two brakes, the first brake and the second brake. The system includes first means for closing or releasing the first or second brake independently of the second brake; second means for increasing the torque on the first or second brake; third means for detecting the slipping of the first or second brake; fourth means for registering the first 30 moments by which the first or second brake slips; fifth means for comparing said first torque with the second torque required for the first or second brake; and means for controlling the wear of the first or second brake register 35.

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In one embodiment of the invention, brake testing is performed automatically at regular intervals when the elevator is in transport. Testing shall be carried out with the elevator empty or at a known load so that the load can be taken into account in the calculation of the torque. Whether the elevator is empty is determined, for example, by a basket scales or by optical photocells in the basket. For example, the test interval corresponds to a certain number of starts or a specific time interval for the drive. In one embodiment of the invention, the assignment-10 li is configurable to a control unit.

In one embodiment of the invention, the elevator drive mechanism, particularly the motor, is electronically adjustable or otherwise variable speed. Electronic control is based, for example, on alternating voltage and variable frequency control.

In one embodiment of the invention, the brake slip to-20 is detected from a tachometer, pulse sensor, or other device directly or indirectly measuring the movement of the drive wheel.

In one embodiment of the invention, the increase of the 25 torque on the brake is effected by the elevator drive mechanism.

In one embodiment of the invention, the momentum applied to the brake is increased by means of the elevator drive mechanism and by natural imbalances, for example the counterweight associated with the lifting rope.

The advantages of the invention are related to improved safety. Periodically checking the condition of the brakes, even outside of service visits, significantly reduces the risk of 35 uncontrolled starts.

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LIST OF FIGURES

Figure 1 shows a prior art elevator system, and Figure 2 shows a method of testing the brakes of an elevator machine according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 2 illustrates an example of a method for testing elevator machine brakes according to the present invention. The elevator system under test is, for example, according to Figure 1.

In step 200, it is checked whether elevator car 102 has been provided with N starts, i.e. starters. Starting refers to starting the engine so that the elevator car 102 can be moved from one floor to another, for example to serve a basket call from the user. For example, the number N may be 1000 or any other corresponding lu-20 ku which represents the range of automatic brake condition testing. For the purposes of this specification, the term brake means, for example, a separate brake drum with associated devices or other types of brake. The term brake, as used herein, may also mean a set of more than one brake or brake device being tested as a unit. The brake may be located adjacent to a motor or drive wheel, such as brakes 160-162, or alternatively also to an elevator car such as grips 154-156. The test interval can be entered into the control system 114 either at the factory or during service. In one embodiment of the invention, the test may also be performed periodically based, for example, on a timer or a clock device located in connection with the control system 114. If in step 200 it is determined that the number of starts N has not yet been executed, return to step 200 to wait for the next 8 starts. Once N starts have been completed, proceed to step 202. In one embodiment of the invention, it is also checked whether the elevator car 102 is free of passengers.

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In step 202, the doors of the elevator car 102 are closed. In step 204, all the brakes except the one being tested are released.

10 In step 206, the torque of the motor 110 is increased. This is done, for example, by increasing the supply voltage to the motor 110. The voltage increase, for example, is linear over time. The torque is increased in step 206 until it is detected in step 208 15 that the elevator car 102 is moving or the brake is slipping. In one embodiment of the invention, the torque is increased only up to a certain upper limit. In one embodiment of the invention, the torque of the motor 110 is increased by 25% up to the ar-20 power corresponding to the load. This 25% upward torque of the motor, combined with the upward momentum of the counterweight, produces an upward pulling force F. When applied to the brakes, the force F is equivalent in value to the downward force exerted by the 125% load on the body. Thus, by combining upward momentum generated by the engine and upward momentum caused by counterweight when the car is empty, a force corresponding to the overload of the car can be applied to the brakes. The motor torque in this application can also be increased to a higher or pie-3 0 value.

In step 210, the torque value at which the elevator car 102 is started is checked. In one embodiment of the invention, it is checked whether the elevator car 35 102 has moved at all. Movement as used herein refers to significant or measurable movement. The movement can be measured, for example, from the tachometer of the motor 110 or from the tachometer connected to the drive wheel 106 or the motor 110. The movement can also be measured from the elevator car 102 by means of optical cells. A very small movement can also be considered a movement. For example, a 5-10 mm movement is sufficient. If the torque caused by the movement of the elevator car 102 falls below the required threshold, it can be stated that the brake under test is not sufficient and proceeds to step 216. In one embodiment of the invention, the measured torque at which the car has moved is recorded. The measured torque is stored, for example, in a log file of the control system 114. It may also be reported to a service center.

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In step 214, it is checked whether there are still unchecked brakes. If there are any, go back to step 204. In step 216, the brake is found to be worn. In this case, the elevator is usually shut down and a fault report is given to the service center. The lift can also be equipped with a remote monitoring system, which can be used to send information about maintenance needs to the service.

In the elevator system of Figure 1, the brake test is performed by first opening the brake 160, after which the moment that the brake 162 of the elevator car is stationary is measured. The brake 162 is then opened, after which the moment that the brake 160 of the elevator car is stationary is measured.

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The invention is not limited only to the above exemplary embodiments, but many modifications are possible within the scope of the inventive idea defined by the claims. By way of example, the method according to the invention is applicable to different machines, different hoisting ropes and different elevators.

Claims (15)

A method for testing the condition of the brakes in an elevator machinery, characterized in that the elevator machinery comprises two brakes, a first brake and a second brake, and the method comprises the steps of: 5. applying the first brake and releasing the second brake; the torque acting on the first brake is increased; a first torque at which the first brake slides is recorded; a second torque is determined, which is required by the first brake; the first torque of the first brake is compared with the second torque of the first brake; if the first brake of the first brake is found to be less than the second brake of the first brake, the first brake is found to be worn; the second brake is applied and the first brake is relieved; the torque acting on the second brake is increased; 15. a first step at which the second brake slides is recorded; a second torque is determined, which is required by the second brake; the first brake second torque is compared with the second brake second torque; if the first brake of the second brake is found to be less than the second of the second brake, the second brake is found to be worn. Method according to claim 1, characterized in that the brakes are automatically tested at regular intervals when the elevator is tower. Method according to claim 2, characterized in that the interval corresponds to a certain number of starts of the lifting machine. 25 Method according to claim 3, characterized in that the elevator machinery is controlled electronically. Method according to claim 1, characterized in that the slimming of the brake is detected with a tachometer, an encoder or other device which directly or indirectly measures the movement of the drive disk. 30 The method according to claim 1, characterized in that the method further comprises the step where the elevator car is found to be a tower. Process according to claim 1, characterized in that the torque acting on the brake is increased by means of the lifting machinery. Method according to claim 1, characterized in that the torque acting on the brake is increased with the help of the lifting machinery and the natural imbalance. A system for testing the condition of the brakes for a lifting machine, characterized in that the lifting machine comprises two brakes, a first brake and a second brake, and the system comprises: a first equipment which applies or relieves the first brake or the second brake independent of other brakes; a second equipment which increases the torque acting on the first or second brake; a third equipment detecting the slimming of the first or second brake; io - a fourth device which registers a first torque at which the first or second brake slides; a fifth device comparing the first torque to the second torque required for the first or second brake; equipment that records the wear of the first or second brake. System according to claim 9, characterized in that the brakes are automatically tested at regular intervals when the lift is empty. System according to claim 10, characterized in that the interval corresponds to a certain number of starts of the lifting machine. System according to claim 9, characterized in that the elevator machinery is controlled electronically. The system according to claim 9, characterized in that the system comprises equipment that detects when the elevator car is empty. System according to claim 9, characterized in that the other equipment comprises the lifting machinery. System according to claim 9, characterized in that the other equipment comprises the lifting machine and the counterweight.