EP3239087A1

EP3239087A1 - A rescue control system for an elevator

Info

Publication number: EP3239087A1
Application number: EP16167429.6A
Authority: EP
Inventors: Jari Kantola; Esa Putkinen
Original assignee: Kone Corp
Current assignee: Kone Corp
Priority date: 2016-04-28
Filing date: 2016-04-28
Publication date: 2017-11-01

Abstract

The invention relates to a rescue control system for an elevator, which said elevator comprises an elevator motor (1) and a first brake (10) and a second brake (20) for braking the elevator motor (1). The rescue control system comprises a mechanical brake lever (11) connected to the first brake (10) with a mechanical wire (12) for controlling the first brake (1); and an electrical brake control unit (21) connected to the second brake (20) for controlling the second brake (20).

Description

FIELD OF THE INVENTION

The present invention relates to a rescue control system of an elevator, and more particularly to a rescue control system for rescuing trapped passengers in an elevator by using the rescue control system as defined in the independent claim 1.

BACKGROUND OF THE INVENTION

The invention relates to machine room-less elevator systems which do not require a machine room on top of the elevator hoistway. The machine room-less elevators use permanent magnets to boost the power of the motor. This reduces the size of the motor so that it is small enough to fit within the elevator hoistway rather than requiring a separate machine room. Machine room-less elevators eliminate the need for a machine room or a control room by attaching the hoisting machine to the guide rail, and placing all control and logic components within the confines of the hoistway.
In the machine room-less elevator systems the elevator brake is no longer easily accessible because there is no machine room. So the conventional rescue systems which require accessing the brake in the machine room are no longer applicable. Therefore, rescue of passengers trapped in a machine room-less elevator system under an emergency circumstance, such as an electricity outage or control system failure, becomes an important issue.
A conventional system involves applying voltage to the motor coils of the brake. Such a system repeatedly energizes and de-energizes the brake coils to alternately release and apply the brake of the elevator car. When the elevator moves too fast, the elevator rescue system applies voltage to the motor coils so that the brake is fully open and when the elevator moves too slowly, the rescue system applies voltage to the motor coils so that the brake is fully off and the elevator car moves freely. The brake in the conventional rescue system is always fully on or off, which causes vibrations on the elevator car as the elevator car drifts to the nearest floor door. The brake is usually an external drum type brake which is actuated by spring force and held open electrically. A power failure will cause the brake to engage and prevent the elevator from falling.
Typical elevator machinery comprises double brakes which are opened by using mechanical brake lever when there is no power in the building. When rescue operator opens brakes manually the safety of speed control is done by dynamic braking.
Safe operation of an elevator system in the event of a malfunction, such as an electricity outage, is ensured with the machinery brake of a hoisting machine. In addition, so-called dynamic braking is often used in elevator hoisting machines, in which case the windings of the hoisting machine are short-circuited with dynamic braking switches, e.g. during a standstill of an elevator. Racing of the hoisting machine can be prevented with a short-circuit of the windings because when the hoisting machine moves the source voltage induced in the short-circuited windings produces a current that endeavors to brake the movement of the hoisting machine. Most of the electrical energy produced in dynamic braking is converted to heat in the winding resistances of the hoisting machine.
One of the problems associated with the machine room-less elevators and especially those having a permanent magnet motor is that braking torque generated in dynamic braking is not sufficient enough because of lesser winding. Therefore, elevator car intends to accelerate until braking operation becomes unstable and rescue operation must be performed with mechanical brake lever in a discontinuous manner such that brake is opened and closed again manually to avoid unstable condition. There is another problem with the manually opening the brake lever because serviceman does not necessarily have direct eye contact to the movement of traction sheave or even if he has it is still difficult to control manually the brake lever.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is thus to provide a rescue control system for an elevator so as to overcome the above problems. The objects of the invention are achieved by a rescue control system which is characterized by what is stated in the independent claim. The preferred embodiments of the invention are disclosed in the dependent claims.
According to the invention a rescue control system is provided for an elevator which said elevator comprises an elevator motor, a first brake and a second brake for braking the elevator motor. The rescue control system comprises a mechanical brake lever connected to the first brake with a mechanical wire for controlling the first brake and an electrical brake control unit connected to the second brake for controlling the second brake. The invention is based on the idea of providing a rescue control system that comprises a mechanical brake lever and an electrical brake control unit which work together such that when activating the mechanical brake lever a first brake connected through a wire to the mechanical brake lever opens and at the same time a second brake opens via a signal from the electrical brake control unit which has received an impulse from the mechanical brake lever preferably through a micro switch. The rescue control system is an elevator rescue drive braking system for operating the brakes during operation of an elevator system in the event of a malfunction.
In other words in a preferred embodiment of the invention the mechanical brake lever activates a micro switch which is connected to a separate electrical brake control unit such that when the brake lever is operated, brakes are opened but velocity of the elevator car is controlled at the same time with the electrical brake control unit by feeding impulses to the second brake. This means that the electrical brake control unit controls the velocity of the elevator car such that during a rescue operation the serviceman only has to keep the mechanical brake lever in an open position.
Activating the mechanical brake lever and activating the electrical brake control unit means that the brake in question opens which means that the elevator car will move. Applying the brake means that the brake in question works and the elevator car will be stopped.
In a preferred embodiment of the invention the mechanical brake lever controls the first brake and the electrical control unit controls the second brake in a pulsed manner. That way the brakes can still be applied even if the electrical brake control unit fails in operation.
An advantage of the rescue control system of the invention is that the brake operation mechanics is lighter so less power has to be used due to only one if the brake openers is manual while the other one is electrical.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawing, in which

Figure 1 shows one embodiment of the configuration of the rescue control system according to the invention; and
Figure 2 shows another embodiment of the configuration of the rescue control system according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a configuration of the rescue control system according to the invention in which braking of the elevator motor 1 is performed with a first brake 10 and a second brake 20 such that a mechanical brake lever 11 is connected to the first brake 10 with a wire 12 for mechanically controlling the first brake 10 and an electrical brake control unit 21 is connected to the second brake 20 for controlling the second brake 20. In other words double brakes are used in the machinery in which the first brake 10 is opened mechanically and the second brake 20 is opened electrically but both brakes are controlled with the same lever 11.
The rescue control system starts when the mechanical brake lever 11 is turned which activates the rescue control system. By turning the mechanical brake lever 11 the first brake 10 is opened by the mechanical wire 12 and at the same time the electrical brake control unit 21 is activated by a micro switch 22 connected between the mechanical brake lever 11 and the electrical brake control unit 21. Activating the electrical brake control unit 21 the elevator car velocity can be controlled by feeding control pulses to the second brake 20 from the electrical brake control unit 21 while the first brake 10 is open.
So the electrical brake control unit 21 takes care of velocity control of the elevator car by operating the second brake 20 in a pulsed manner. The operation of the second brake 20 can be done in different ways. The first way is that the electrical brake control unit 21 gives pulsed voltage to the second brake 20 based on a data about the velocity of the elevator car. The data can be received from a speed detector which is more explained in connection with figure 2. The second way is that the electrical brake control unit 21 gives pulses to the second brake 20 to avoid over speed independently from the velocity of the elevator car. This means that there is no feedback data from the elevator car but the pulses need not to be given on a constant frequency. Third way is that the electrical brake control unit 21 gives one pulse which has a specified duration to the second brake 20 which means that there is a time delay setting which opens the second brake 20 for a predefined time and after that the brake should be opened manually again for a new pulse. This is to control that there is no-one holding the mechanical brake lever 11 such that the brakes are open all the time and that the velocity of the elevator car would accelerate.
Figure 2 shows another embodiment of the configuration of the rescue control system according to the invention in which the rescue control system works as normal mechanical brake lever as described in connection with the figure 1 but include speed limitation and optional speed control.
Braking of the elevator motor 1 is performed with the first brake 10 and the second brake 20 such that a mechanical brake lever 11 is connected to the first brake 10 with a mechanical wire 12 for controlling the first brake 1 and an electrical brake control unit 21 is connected to the second brake 20 for controlling the second brake 20. The mechanical brake lever 11 is arranged to directly activate the opening of the first brake 10 and indirectly activate the opening of the second brake 20, which the directly activating the first brake 10 means that there is the wire 12 which is arranged between the mechanical brake lever 11 and the first brake 10 and the indirectly activating the second brake 20 means that the activation of the second brake 20 is arranged to happen through the electrical brake control unit 21 which is connected to the second brake 20 and also via a micro switch 22 to the mechanical brake lever 11. The mechanical brake lever 11 is therefore arranged to activate the second brake 20 via the electrical brake control unit 21. The first and the second brake 10, 20 are arranged to be opened at the same time when the mechanical brake lever 11 is turned. So the mechanical brake lever 11 is arranged to activate the opening of the second brake 20 via the electrical brake control unit 21.
In this embodiment of the invention the rescue control system further comprises a measurement device 23, such as an encoder or a sensor, for measuring the velocity of the elevator car. The measurement device 23 can be for example a speed detector which determines the velocity of the elevator car in the hoistway and generates a speed control signal corresponding to the velocity of the elevator car. The speed encoder determines the position of the elevator car along the hoistway and with further known methods generates a speed control signal having a signal magnitude corresponding to the velocity of the elevator car. The measurement device 23 and the electrical brake control unit 21 are connected together for transferring speed data of the elevator car in a form of a speed control signal to the electrical brake control unit 21 for controlling the second brake 20. In other words the measurement device 23 and the electrical brake control unit 21 are coupled together such that speed data of the elevator car is transferred to the electrical brake control unit 21 for controlling the second brake 20. The electrical brake control unit 21 is arranged to give pulsed voltage to the second brake 20 for releasing and applying the second brake 20. In one embodiment of the invention the pulsed voltage is based on the data of the velocity of the elevator car received from the measurement device 23. In another embodiment of the invention the pulsed voltage given by the electrical brake control unit 21 is not correlated to the velocity of the elevator car. In still another embodiment of the invention the electrical brake control unit 21 is arranged to give only one pulse having a specified length to the second brake 20 when the mechanical brake lever 11 is activated. The mechanical brake lever 11 and the electrical brake control unit 21 are connected together such that there is a micro switch 22 between the mechanical brake lever 11 and the electrical brake control unit 21.
It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

A rescue control system for an elevator, said elevator comprising an elevator motor (1) and a first brake (10) and a second brake (20) for braking the elevator motor (1), characterized in that the rescue control system comprises:
a mechanical brake lever (11) connected to the first brake (10) with a mechanical wire (12) for controlling the first brake (1); and

an electrical brake control unit (21) connected to the second brake (20) for controlling the second brake (20).
A rescue control system according to claim 1, characterized in that the mechanical brake lever (11) is arranged to directly activate the opening of the first brake (10) and indirectly activate the opening of the second brake (20).
A rescue control system according to claim 1 or 2, characterized in that the mechanical brake lever (11) is arranged to activate the opening of the second brake (20) via the electrical brake control unit (21).
A rescue control system according to any preceding claim, characterized in that the first and the second brake (10, 20) are arranged to be opened at the same time when the mechanical brake lever (11) is turned.
A rescue control system according to any preceding claim, characterized in that the rescue control system further comprises a measurement device (23), such as an encoder or sensor, for measuring the velocity of the elevator car, said measurement device (23) and the electrical brake control unit (21) being coupled together such that speed data of the elevator car is transferred to the electrical brake control unit (21) for controlling the second brake (20).
A rescue control system according to any preceding claim, characterized in that the electrical brake control unit (21) is arranged to give pulsed voltage to the second brake (20) for releasing and applying the second brake (20).
A rescue control system according to claim 6, characterized in that the pulsed voltage is based on the data of the velocity of the elevator car received from the measurement device.
A rescue control system according to claim 6, characterized in that the pulsed voltage given by the electrical brake control unit (21) is not correlated to the velocity of the elevator car.
A rescue control system according to claim 6, characterized in that the electrical brake control unit (21) is arranged to give only one pulse having a specified length to the second brake (20) when the mechanical brake lever (11) is activated.
A rescue control system according to any preceding claim, characterized in that the mechanical brake lever (11) and the electrical brake control unit (21) are connected together such that there is a micro switch (22) between the mechanical brake lever (11) and the electrical brake control unit (21).