DESCRIPTION ELEVATOR APPARATUS
TECHNICAL FIELD
[0001]
The present invention relates to an elevator apparatus that reduces deceleration of a car during urgent stopping of the car.
BACKGROUND ART
[0002]
In conventional elevator braking apparatuses, braking force of an electromagnetic brake is controlled based on a deceleration command value and a speed signal during emergency braking in such a way that deceleration of a car is at a predetermined value (see Patent Literature 1, for example).
[0003] [Patent Literature 1]
Japanese Patent Laid-Open No. HEI 7-157211 (Gazette)
DISCLOSURE OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0004]
In conventional braking apparatuses such as that described above, if the control portion that controls the deceleration has failed, for example, there is a possibility that the stopping distance may be lengthened even if it is desirable to stop the car immediately since attempts are made constantly to try to control the deceleration of the car once the urgent stopping command is issued.
[0005]
The present invention aims to solve the above problems and an object of the present invention is to provide an elevator apparatus that can switch action of a braking device easily between a case in which deceleration of a car is to be reduced and a case in which the car is to be stopped immediately when an urgent stopping command is issued for the car.
MEANS FOR SOLVING THE PROBLEM
1

[0006]
In order to achieve the above object, according to one aspect of the present invention, there is provided an elevator apparatus including: a car; a braking device that stops motion of the car; a safety circuit that has a plurality of contacts that are connected to each other in series, and that makes the car stop urgently using the braking device if at least one of the contacts is opened; and a deceleration-reducing brake control portion that reduces braking force from the braking device to reduce deceleration of the car during the urgent stopping of the car by the braking device, wherein: a disabling contact that is constituted by at least one preselected contact, and an enabling contact that is constituted by at least one contact that does not include the disabling contact are included in the contacts; and the safety circuit is configured so as to disable deceleration reducing control by the deceleration-reducing brake control portion when the disabling contact is opened, and so as to enable deceleration reducing control by the deceleration-reducing brake control portion if the enabling contact is open and the disabling contact is closed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007]
Figure 1 is a structural diagram that shows an elevator apparatus according to Embodiment 1 of the present invention;
Figure 2 is a circuit diagram that shows a control circuit for controlling a braking device from Figure 1;
Figure 3 is a circuit diagram that shows a safety circuit from the elevator apparatus in Figure 1;
Figure 4 is a structural diagram that shows an elevator apparatus according to Embodiment 2 of the present invention;
Figure 5 is a circuit diagram that shows a control circuit for controlling a braking device from Figure 4; and
Figure 6 is a circuit diagram that shows a circuit that drives main contacts from Figure 5.
BEST MODE FOR CARRYING OUT THE INVENTION
[0008]
Preferred embodiments of the present invention will now be explained with reference to the drawings.
2

Embodiment 1
Figure 1 is a structural diagram that shows an elevator apparatus according to Embodiment 1 of the present invention. A car 1 and a counterweight 2 are suspended inside a hoistway by a main rope 3, and are raised and lowered inside the hoistway by a driving force from a hoisting machine 4. The hoisting machine 4 has: a drive sheave 5 onto which the main rope 3 is wound; a motor 6 that rotates the drive sheave 5; and a braking means 7 that brakes rotation of the drive sheave 5.
[0009]
The braking means 7 has: a brake wheel 8 that is rotated together with the drive sheave 5; and a braking device 9 that brakes rotation of the brake wheel 8. The braking device 9 has: a brake shoe 10 that can be placed in contact with and separated from the brake wheel 8; a brake spring 11 that presses the brake shoe 10 against the brake wheel 8; and a brake coil 12 that separates the brake shoe 10 from the brake wheel 8 in opposition to the brake spring 11.
[0010]
A speed detector 13 that generates a signal that corresponds to rotational speed of a rotating shaft of the motor 6, i.e., rotational speed of the drive sheave 5, is disposed on the motor 6. An encoder or a resolver, for example, can be used for the speed detector 13.
[0011]
An elevator control apparatus 14 has: a power converting device 15 such as an inverter, etc.; a running control portion 17 that controls running of the car 1; and a main brake control portion 18 that controls the braking device 9. The power converting device 15 supplies electric power to the motor 6. The running control portion 17 controls the power converting device 15 and the main brake control portion 18 in response to the signal from the speed detector 13. The main brake control portion 18 controls the braking device 9 in accordance with a command from the running control portion 17.
[0012]
A deceleration-reducing brake control portion 19 is connected to the brake coil 12 in parallel to the main brake control portion 18, and can reduce the braking force of the braking device 9 independently from the main brake control portion 18.
3

[0013]
The main brake control portion 18 makes the braking device 9 perform a braking action and holds the car 1 in a stationary state when the car 1 is stopped at service floors during normal operation. The main brake control portion 18 also makes the braking device 9 perform the braking action when a command is issued to make the car 1 stop urgently while the car 1 is in motion. However, here, if the deceleration of the car 1 is greater than or equal to a predetermined value, the braking force of the braking device 9 is reduced by the deceleration-reducing brake control portion 19, and is controlled such that the deceleration of the car 1 is not greater than or equal to the predetermined value. The deceleration-reducing brake control portion 19 monitors to find the deceleration of the car 1 based on the signal from the speed detector 13.
[0014]
The elevator control apparatus 14 includes a first computer that has: a data processing portion (CPU); a storage portion (ROM, RAM, hard disk, etc.); and a signal input-output portion. The functions of the running control portion 17 and the main brake control portion 18 are implemented by the first computer.
[0015]
The deceleration-reducing brake control portion 19 includes a second computer that has: a data processing portion (CPU); a storage portion (ROM, RAM, hard disk, etc.); and a signal input-output portion. The functions of the deceleration-reducing brake control portion 19 are implemented by the second computer.
[0016]
An upper terminal switch 41 is disposed in a vicinity of an upper terminal floor inside the hoistway. A lower terminal switch 42 is disposed in a vicinity of the lower terminal floor inside the hoistway. A plurality of car position detecting switches 43 for detecting absolute position of the car 1 are also disposed inside the hoistway. In addition, a speed governor switch 44 that detects overspeeding of the car 1 is disposed in an upper portion of the hoistway. A car door switch 45 that detects an open or closed state of a car door is disposed on the car 1.
[0017]
Signals from the switches 41 through 45 are input into a safety circuit main body 40. The car position detecting switches 43 are switches used by a
4

terminal floor forced decelerating device, and the car 1 is urgently stopped by the safety circuit main body 40 if the speed of the car 1 becomes greater than an overspeed pattern that is preset according to car position. The overspeed pattern in the terminal floor forced decelerating device is set so as to become gradually lower as the car 1 approaches the upper and lower terminal floors of the hoistway.
[0018]
Figure 2 is a circuit diagram that shows a control circuit for controlling the braking device 9 from Figure 1. The main brake control portion 18 and the deceleration-reducing brake control portion 19 are connected to the brake coil 12 in parallel. In other words, the braking force of the braking device 9 is released if power is supplied from at least one of either the main brake control portion 18 or the deceleration-reducing brake control portion 19.
[0019]
The main brake control portion 18 supplies electric power to the brake coil 12 from a first power source 22 by closing a pair of main contacts 21. A first semiconductor switch 23 such as a metal oxide semiconductor field-effect transistor (MOSFET), etc., is connected between the first power source 22 and the main contacts 21. The first semiconductor switch 23 generates an average voltage that corresponds to a ratio of on-off time by performing switching at high speed (a step-down chopper). The first semiconductor switch 23 is controlled by a command signal that is generated by the first computer in the elevator control apparatus 14.
[0020]
A first flyback diode 24 is connected to the first power source 22 in parallel to the brake coil 12. The first flyback diode 24 protects the circuit from reverse electromotive forces that arise in the brake coil 12.
[0021]
The deceleration-reducing brake control portion 19 supplies electric power to the brake coil 12 from a second power source 26 by closing a pair of deceleration control contacts 25. A second semiconductor switch 27 such as a MOSFET, etc., and a resistor 29 that functions as a current limiting resistance is connected between the second power source 26 and the deceleration control contacts 25. The second semiconductor switch 27 generates an average voltage that corresponds to a ratio of on-off time by performing switching at high speed (a step-down chopper). The second
5

semiconductor switch 27 is controlled by a command signal that is generated by the second computer in the deceleration-reducing brake control portion 19.
[0022]
The resistor 29 limits current that flows to the brake coil 12 even if an on fault arises in the second semiconductor switch 27. A second flyback diode 28 is connected to the second power source 26 in parallel to the brake coil 12. The second flyback diode 28 protects the circuit from reverse electromotive forces that arise in the brake coil 12.
[0023]
A circuit in which a diode 30 and a resistor 31 are connected in series is connected in parallel to the brake coil 12. The circuit that is constituted by the diode 30 and the resistor 31 promptly consumes reverse electromotive force that arises in the brake coil 12 when the main contacts 21 or the deceleration control contacts 25 are open.
[0024]
Figure 3 is a circuit diagram that shows a safety circuit from the elevator apparatus in Figure 1. A deceleration control relay coil 25a that switches on the deceleration control contacts 25 and a safety relay coil 49 that permits activation of the car 1 are disposed in a safety circuit main body 40.
[0025]
A contact 41a of the upper terminal switch 41, a contact 42a of the lower terminal switch 42, a contact 43a of a car position detecting switch 43, a contact 44a of the speed governor switch 44, a contact 45a of the car door switch 45, contacts 46 of a plurality of landing door switches that detect opening and closing of the landing doors of respective floors, a contact 47 of a switch that detects opening and closing of a rescue hatch that is disposed on a roof of the car 1, and a contact 48 of a stop switch that prevents activation of the car 1 during maintenance, etc., are connected to the safety relay coil 49 in series.
[0026]
The contact 41a is opened when the car 1 reaches a position of the upper terminal switch 41. The contact 42a is opened when the car 1 reaches a position of the lower terminal switch 42. The contact 43a is opened when the car 1 reaches a position of the car position detecting switch 43. The contact 44a is opened when the overspeeding of the car 1 is detected by the speed governor. The contact 45a is opened when the car door opens.
6

[0027]
The deceleration control relay coil 25a is connected in parallel to the contacts 46 through 48, which constitute enabling contacts, and the safety relay coil 49, and is connected in series to the contacts 41a through 45a, which constitute disabling contacts. Consequently, when all of the contacts 41a through 48 are closed, the safety relay coil 49 is energized, and activation of the car 1 is permitted. When at least one of the contacts 41a through 48 is opened, supply of electric power to the power converting device 15 and the main brake control portion 18 is interrupted, and the car 1 is urgently stopped. The running control portion 17 also monitors the state of the safety relay coil 49, and a command that stops activation of the car 1 is output from the running control portion 17 when the safety relay coil 49 is de-energized.
[0028]
In addition, because the deceleration control relay coil 25a is also de-energized in addition to the safety relay coil 49 if at least one of the contacts 41a through 45a is opened, the deceleration-reducing brake control portion 19 is disconnected from the brake coil 12, disabling deceleration reducing control by the deceleration-reducing brake control portion 19.
[0029]
Furthermore, deceleration reducing control will be implemented by the deceleration-reducing brake control portion 19 if at least one of the contacts 46 through 48 is opened when the contacts 41a through 45a are closed since the safety relay coil 49 will be de-energized but the deceleration control relay coil 25a will remain energized.
[0030]
In an elevator apparatus of this kind, because deceleration reducing control by the deceleration-reducing brake control portion 19 is disabled when the contacts 41a through 45a, which constitute disabling contacts, are opened, and deceleration reducing control by the deceleration-reducing brake control portion 19 is enabled if the enabling contacts 46 through 48 are open and the disabling contacts 41a through 45a are closed, action of the braking device 9 can be switched easily between a case in which the deceleration of the car 1 is to be reduced and a case in which the car 1 is to be stopped immediately when an urgent stopping command is issued for the car 1.
[0031]
Because the deceleration control relay coil 25a is connected to the
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disabling contacts 41 a through 45a in series, and is connected to the enabling contacts 46 through 48 in parallel, the enabling and disabling of the deceleration reducing control can be switched by a simple configuration.
[0032]
In addition, because the contact 45a of the car door switch 45 is set as a disabling contact, in the unlikely event that the car doors are opened while the car 1 is in motion, the car 1 can be stopped immediately in the shortest distance without performing deceleration reducing control.
[0033]
Because the contact 44a of the speed governor switch 44 is set as a disabling contact, in the unlikely event that the deceleration-reducing brake control portion 19 fails and the brake shoe 10 remains separated from the brake wheel 8, the car 1 can be stopped immediately as soon as the car 1 starts to overspeed.
[0034]
Because the contact 43a of the car position detecting switch 43 is set as a disabling contact, in the unlikely event that the deceleration-reducing brake control portion 19 fails and the brake shoe 10 remains separated from the brake wheel 8, the car 1 can be stopped immediately in the shortest distance when the car 1 reaches the position of the car position detecting switch 43.
[0035]
In addition, because the contacts 41a and 42a of the terminal switches 41 and 42 are set as disabling contacts, in the unlikely event that the deceleration-reducing brake control portion 19 fails, the car 1 can be stopped immediately in the shortest distance when the car 1 reaches a position of the terminal switches 41 and 42. Consequently, the car 1 will not be accelerating while entering the ends of the hoistway.
[0036]
Because the deceleration-reducing brake control portion 19 controls the braking device 9 independently from the main brake control portion 18, emergency braking action can be started more reliably and promptly while suppressing deceleration during emergency braking.
[0037] Embodiment 2

Next, Figure 4 is a structural diagram that shows an elevator apparatus according to Embodiment 2 of the present invention. In the figure, an elevator control apparatus 14 has: a power converting device 15; a running control portion 17; and a brake control portion 20.
[0038]
The brake control portion 20 holds a car 1 in a stationary state using a braking device 9 when the car 1 is stopped. The brake control portion 20 also makes the braking device 9 perform a braking action when a command is issued to make the car 1 stop urgently. However, here, if the deceleration of the car 1 is greater than or equal to a predetermined value, the braking force of the braking device 9 is reduced, and is controlled such that the deceleration of the car 1 is not greater than or equal to the predetermined value. The brake control portion 20 monitors the deceleration of the car 1 based on the information from the running control portion 17.
[0039]
Thus, the brake control portion 20 according to Embodiment 2 functions as both the main brake control portion 18 and the deceleration-reducing brake control portion 19 according to Embodiment 1. In other words, in Embodiment 2, the brake control portion 20 constitutes a deceleration-reducing brake control portion.
[0040]
Figure 5 is a circuit diagram that shows a control circuit for controlling the braking device 9 from Figure 4. The control circuit in Figure 5 is similar to the control circuit in Figure 2 with the deceleration-reducing brake control portion 19 removed. The semiconductor switch 23 is controlled by a command signal that is generated by a computer in the elevator control apparatus 14. In addition, a safety circuit according to Embodiment 2 is configured in a similar manner to that in Figure 3.
[0041]
Figure 6 is a circuit diagram that shows a circuit that drives main contacts 21 from Figure 5. A contact 25b is opened by de-energizing a deceleration control relay coil 25a of the safety circuit, and is closed by energizing the deceleration control relay coil 25a. A contact 50 and a main contact coil 21a are connected to the contact 25b in series. The contact 50 is opened and closed in response to a driving command from the running control portion 17. Specifically, the contact 50 is closed when the driving command is
9

output from the running control portion 17. The main contacts 21 are closed when the main contact coil 21a is energized, and the main contacts 21 are opened when the main contact coil 21a is de-energized.
[0042]
Consequently, if the deceleration control relay coil 25a is energized and the contact 25b is closed, and the driving command has been output from the running control portion 17, braking control during normal operation and deceleration reducing control during an emergency can be implemented.
[0043]
In contrast to that, since the main contacts 21 are open if the contact 25b is open, the car 1 is urgently stopped, and deceleration reducing control is also disabled.
[0044]
Using a configuration such as that described above, action of the braking device 9 can be switched easily between a case in which deceleration of a car 1 is to be reduced and a case in which the car 1 is to be stopped immediately when an urgent stopping command is issued for the car 1, even if the brake control portion 20 serves as both the main brake control portion and the deceleration-reducing brake control portion.
[0045]
Moreover, in the above examples, the deceleration of the car 1 is found based on signals from a speed detector 13 that is disposed on the motor 6, but the deceleration of the car may also be found, for example, based on output from a speed detector that is disposed on a speed governor, or an acceleration sensor that is disposed on the car, etc.
In the above examples, deceleration reducing control was performed using arithmetic processing by a computer in a deceleration-reducing brake control portion, but may also be performed by an electrical circuit that processes analog signals.
In addition, in the above examples, the car 1 being positioned in a vicinity of a terminal floor is detected using signals from terminal switches 41 and 42, but may also be detected, for example, using car position information that is found based on signals from a speed detector that is disposed on a speed governor, or a speed detector that is disposed on a hoisting machine, etc.
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In the above examples, the braking device 9 is disposed on the hoisting machine 4, but may also be disposed at other positions. In other words, the braking device may also be, for example, a car brake that is mounted to a car, or a rope brake that brakes the car by gripping the main rope, etc.
A braking device that has a plurality of brake shoes that each act to brake and release independently may also be used.
In addition, neither the disabling contacts nor the enabling contacts are limited to a particular number.
11

CLAIMS
1. An elevator apparatus comprising:
a car;
a braking device that stops motion of the car;
a safety circuit that has a plurality of contacts that are connected to each other in series, and that makes the car stop urgently using the braking device if at least one of the contacts is opened; and
a deceleration-reducing brake control portion that reduces braking force from the braking device to reduce deceleration of the car during the urgent stopping of the car by the braking device,
wherein:
a disabling contact that is constituted by at least one preselected contact, and an enabling contact that is constituted by at least one contact that does not include the disabling contact are included in the contacts; and
the safety circuit is configured so as to disable deceleration reducing control by the deceleration-reducing brake control portion when the disabling contact is opened, and so as to enable deceleration reducing control by the deceleration-reducing brake control portion if the enabling contact is open and the disabling contact is closed.
2. The elevator apparatus according to Claim 1, wherein:
a deceleration control relay coil that enables deceleration reducing control by the deceleration-reducing brake control portion by being energized is disposed in the safety circuit; and
the deceleration control relay coil is connected to the disabling contact in series and is connected to the enabling contact in parallel.
3. The elevator apparatus according to Claim 1, wherein:
a contact of a car door switch that is opened when a car door opens is included in the disabling contacts.
4. The elevator apparatus according to Claim 1, wherein:
a contact of a speed governor switch that is opened when overspeeding of the car is detected is included in the disabling contacts.
12

5. The elevator apparatus according to Claim 1, wherein:
a contact of a car position detecting switch that is used in a terminal floor forced decelerating device is included in the disabling contacts.
6. The elevator apparatus according to Claim 1, wherein:
a contact of a terminal switch that is installed in a vicinity of a terminal floor of a hoistway is included in the disabling contacts.