EP1588974A1

EP1588974A1 - Elevator device

Info

Publication number: EP1588974A1
Application number: EP03701898A
Authority: EP
Inventors: Toshiaki c/o Mitsubishi Denki K. K. ISHII
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2003-01-28
Filing date: 2003-01-28
Publication date: 2005-10-26
Also published as: KR100627539B1; CN100357168C; JPWO2004067428A1; KR20050002894A; WO2004067428A1; EP1588974A4; CN1620399A

Abstract

An elevator system wherein a hoisting machine (11) is mounted on an elevator car (4) or a counterweight (10), comprises a first brake-releasing mechanism (30) and a second brake-releasing mechanism (40) for mechanically releasing brake of a braking device (20) of the hoisting machine (11), in case of malfunction of the elevator. The releasing of brake of the braking device (20) is performed by actuating each of the brake-releasing levers (31,41) by operating operation ropes (33,43) provided in each of the brake-releasing mechanisms from the ground. Furthermore, because the elevator system comprises two sets of brake-releasing mechanisms, it is possible to perform more stable releasing of the braking device (20) with facility and without fail by selecting the brake-releasing mechanism suitable for the situation of the boarding of passengers, regardless of the number of passengers inside the elevator car (4).

Description

Technical Field

The present invention relates to an elevator system wherein a hoisting machine is mounted on an elevator car or a counterweight.

Background Art

With a view to reduce the required space in the hoistway of an elevator as much as possible, there have been suggested elevator systems wherein the hoisting machine is mounted on the elevator car or the counterweight. For example, in Japanese non-examined laid-open patent publication No. Hei 9-124259, there is disclosed an elevator system wherein the hoisting machine is mounted on the counterweight.

However, although the elevator of the type with the hoisting machine mounted on the elevator car or the counterweight has the great advantage of saving space, there is the problem that rescue of trapped passengers in the elevator car due to malfunction of the control device of the elevator is difficult. In the above-mentioned Japanese non-examined laid-open patent publication No. Hei 9-124259, there is disclosed a means for rescuing passengers in an emergency using a manually-operated winding unit. However, rescue by this method has the problem that it is limited to malfunction in the situation where electrical control of opening and closing of the braking device of the hoisting machine mounted on the counterweight is possible. Therefore, it is often the case that it is difficult to drive the elevator by means of a manually-operated winding unit in the event that opening and closing of the braking device from the ground becomes impossible due to malfunction, thus this type still remains with problems.

On the other hand, in Japanese non-examined laid-open patent publication No. Hei 5-147855, there is disclosed a method by which a braking device to brake the elevator car or the counterweight by gripping the guiderails corresponding to the elevator car or the counterweight, with a method of releasing the grip on the guiderails by actuating a lever by using a rope passed around a pair of pulleys provided in an upper part and a lower part of the hoistway and stretched in a loop shape, is disclosed. However, since this braking device has the method of pulling the rope which is coupled with the lever only downward, in the case where, for example, the braking device is provided on the elevator car side, when the elevator car is heavier than the counterweight depending on the situation of the number of persons in the car, the elevator car, of which the grip of the guiderails is released, starts descending once the lever is actuated. That is, because the elevator car moves in the direction which force is exerted by the lever, release of brake of the braking device by the lever cannot always be performed accurately. In other words, there are case where release of brake cannot be performed properly depending on the increase and decrease in the number of persons riding in the car.

The present invention has as its intension to enable rescue of passengers by making it possible for a maintenance worker to mechanically release brake of the braking device from the ground floor in the event that electrical control of opening and closing of the braking device becomes impossible when the elevator stops between floors due to malfunction, and afterwards to move the elevator car to a nearest floor, in an elevator system having a hoisting machine and a braking device mounted on the elevator car or the counterweight.

The present invention also has as its intension to enable more stable release of brake of the braking device, regardless of the number of persons riding in the elevator car.

Disclosure of the Invention

The elevator system in the present invention comprises an elevator car which ascends and descends through the hoistway and a counterweight which travels in the direction opposite to the elevator car; and a hoisting machine is mounted on either the elevator car or the counterweight. A main rope which suspends the elevator car and the counterweight is passed around a drive sheave of the hoisting machine. A braking device which applies brake to the hoisting machine by means of brake springs and also releases brake of the hoisting machine by means of an excited electromagnet by resisting the brake springs is provided on the hoisting machine.

Furthermore, a brake-releasing mechanism for releasing brake of the braking device mechanically by resisting the brake springs is provided on the hoisting machine, separately from the braking device. The brake-releasing mechanism has brake-releasing levers for releasing brake of the braking device by retracting the brake springs, and operation ropes for operating the brake-releasing levers wound around a pair of pulleys which are provided in a part higher and lower than either of the travel area of the elevator car or the counterweight and stretched between the pulleys ; and the brake-releasing levers and the operation ropes are connected via a connecting means.

Moreover, the brake-releasing mechanism is comprised of the below-mentioned two sets of brake-releasing mechanisms (a first and a second). That is, the brake-releasing mechanism is comprised of a first brake-releasing mechanism having a first pair of pulleys, a first operation rope and a first brake-releasing lever, wherein the operation rope is pulled up so as to release brake of the braking device; and a second brake-releasing mechanism having a second pair of pulleys, a second operation rope and a second brake-releasing lever, wherein the operation rope is pulled down so as to release brake of the braking device.

According to the aforementioned invention, even in the case where electrical control of opening and closing of the braking device becomes impossible in the event that the elevator stops between floors due to malfunction, it is possible for a maintenance worker to mechanically release brake of the braking device from the ground, and to move the elevator car to a nearest floor and rescue the passengers. Further, as the elevator system comprises two - a first and second - sets of brake-releasing mechanisms, it is possible to select the brake-releasing mechanism suited to the situation of the riding of the car and to perform a more stable releasing operation of the braking device with facility and also without fail, regardless of the number of persons riding in the elevator car.

Brief Description of the Drawings

Figure 1 is a diagram showing an example of an arrangement of the elevator system in accordance with the first embodiment of the present invention;

Figure 2 is a diagram for explaining the structures of the braking device of the hoisting machine and the brake-releasingmechanismmounted on the counterweight in accordance with the first embodiment of the present invention;

Figure 3 is an elevation for explaining the motion of opening and closing of the braking device in accordance with the first embodiment of the present invention;

Figure 4 is an elevation for explaining the motion of the first brake-releasing mechanism in accordance with the first embodiment of the present invention;

Figure 5 is an elevation for explaining the motion of the second brake-releasing mechanism in accordance with the first embodiment of the present invention; and

Figure 6 is an elevation for explaining the structure of the brake-releasing mechanism of the braking device in accordance with the second embodiment of the present invention.

Best Mode for Carrying out the Invention

To describe the present invention in more detail, the invention will be described by referring to the accompanying drawings. In each of the drawings, the same numerals are given to the same parts or the corresponding parts, and repeated explanation will be appropriately simplified or omitted.

First Embodiment

Figure 1 is a diagram showing an example of an arrangement of the elevator system in accordance with the first embodiment of the present invention; Figure 1(A) is an elevation of the elevator system viewed from the horizontal direction, and Figure 1(B) is a plan view of the elevator system viewed from above.

First: the whole structure of the elevator system in accordance with the first embodiment will be explained referring to Figure 1. Inside the hoistway 1, there are provided a pair of guiderails 2 for the elevator car and another pair of guiderails 3 for the counterweight. The elevator car 4 travels through the hoistway 1 guided by the guiderails 2 for the elevator car, and the counterweight 10 travels through the hoistway guided by the guiderails 3 for the counterweight in the direction opposite to the car 4.

Entrance doors 4a are provided on the front surface of the car 4, and hall doors 5 are provided on the hall side, facing the entrance doors 4a. The counterweight 10 is arranged between the rear surface of the car 4 and the wall of the hoistway 1.

Next: the hoisting machine 11 is mounted on the counterweight 10. On the hoisting machine 11, a braking device 20 which performs opening and closing of brake of the hoisting machine 11 is provided. Furthermore, both ends of the main rope 6 which suspends the elevator car 4 and the counterweight 10 are fixed to an upper part of the hoistway 1, and one of the ends of the main rope 6 is successively wound around a pair of suspension sheaves 7 provided in a lower part of the elevator car 4 starting at the upper part of the hoistway 1, and reaches the direction-changing pulley 8 which is provided in an upper part of the hoistway 1. After it is wound around the direction-changing pulley 8, it is wound around the drive sheave 12 of the hoisting machine 11 mounted on the counterweight 10, and rises again, and the other end of the main rope 6 is fixed to the upper part of the hoistway 1.

Next: the brake-releasing mechanism used in the first embodiment comprises two sets - a first and a second - of brake-releasing mechanisms . The first brake-releasing mechanism 30 has a first brake-releasing lever 31 for mechanically releasing brake of the braking device 20, a pair of first pulleys 32 which are separately provided in a part higher and lower than the travel area of the counterweight 10, and a first operation rope 33 which is passed around the first pulleys 32 and stretched in a loop shape between the first pulleys 32. Similarly, the second brake-releasing mechanism 40 has a second brake-releasing lever 41, second pulleys 42, and a second operation rope 43.

Figure 2 is a diagram for explaining the structures of the braking device of the hoisting machine and the brake-releasingmechanismmounted on the counterweight in accordance with the first embodiment of the present invention; Figure 2(A) is an elevation of the braking device of the hoisting machine viewed from the horizontal direction, and Figure 2(B) is a cross sectional view taken on line C-C of the braking device.

In Figure 2, the external form of the counterweight 10, on which the hoisting machine 11 is mounted, is comprised of a frame body 14, and a weight 15 for the counterweight is mounted in a lower part inside the frame body 14. The hoisting machine 11 comprises a drive sheave 12 around which the main rope 6 is passed, and an electric motor 13 for rotatably driving the drive sheave 12.

Next: the braking device 20 is structured as a part of the hoisting machine 11; and a brake drum 21 is arranged on the same rotation axis as the drive sheave 12 of the hoisting machine 11. A pair of brake shoes 22 is provided facing the circumferential surface of the brake drum 21; and each of the brake shoes 22 is fixed to the brake arms 23. The brake arms 23 receive the force of the braking springs 24 provided between themselves and a side part of the frame body 14 of the counterweight 10, and stops rotation of the brake drum 21 by pressing the brake shoes 22 to the brake drum 21. One of the ends of the brake arms 23 are fixed to the frame body 14 of the counterweight 10 via brake arm pins 23a, and the brake arms 23 pivot with the brake arm pins 23a as their centers. On the other end of the brake arms 23, bolts 25 are fixed, and the brake arms 23 are coupled with brake levers 26 via the bolts 25. The brake levers 26 pivot with brake lever pins 26a as their centers. An electromagnet which drives the braking device 20 is housed in a casing 27 provided on an upper part of the frame body 14 of the counterweight 10. Here in the first embodiment, a plunger 28 is used as a pushing body which is driven by the excited electromagnet. A plunger head 28a, which is an end part of the plunger 28, abuts on the brake levers 26.

Next: in the first brake-releasing mechanism 30, the first brake-releasing lever 31 is formed in a longitudinal shape, and on one end thereof there is provided a pierced first releasing-lever hole 35. The plunger 28 is inserted into this first releasing-lever hole 35. Here, the plunger head 28a is formed to have a larger diameter than the part of the plunger 28 that is inserted into the first brake-releasing lever 31. For this reason, it is possible to couple the plunger head 28a with one end of the first brake-releasing lever 31. In the present invention, this coupling part of the first brake-releasing lever 31 will be referred to as the first releasing-lever coupling part 34. Furthermore, the first brake-releasing lever 31 uses as a supporting-point base 29 a part of the casing 27 which is close to the first brake-releasing lever coupling part 34 and in which the electromagnet is housed; and the supporting point of the first brake-releasing lever 31 is supported by the supporting-point base 29. The other end of the first brake-releasing lever 31 is connected to the first operation rope 33 by means of a connection means. In the first embodiment, an example in which the first brake-releasing lever 31 is constantly fixed to the first operation rope 33 is shown.

Furthermore, in the second brake-releasing mechanism 40, the brake-releasing lever 41 is formed in a longitudinal shape, with the middle part formed in a square-loop shape which surrounds the plunger head 28a. Similarly to the first brake-releasing lever 31, one end of the second brake-releasing lever 41 uses as a supporting point the supporting-point base 29 of the casing 27 of the electromagnet, and normally one end is in a state in which it abuts on the supporting-point base 29. The middle part of the second brake-releasing lever 41 has a second releasing-lever coupling part 44 between itself and the plunger head 28a, and is pivotally connected to the plunger head 28a via the second releasing-lever pin 45. The other end of the second brake-releasing lever 41 is connected to the second operation rope 43 by means of a connection means. In the first embodiment, similarly to the first brake-releasing lever 31, an example in which the second brake-releasing lever 41 is constantly fixed to the second operation rope 43 is shown.

Also, on the side parts of the frame body 14 of the counterweight 10, there are provided releasing-lever holes 16 for inserting the first brake-releasing lever 31 and the second brake-releasing lever 41 respectively. It is structured so that during normal ascent and descent of the elevator car 4, the first brake-releasing lever 31 and the second brake-releasing lever 41 are both fixed to the side parts of the frame body of the counterweight 10 by fixing cords 17, and, in the case where the

levers

31 and 41 are to be actuated in an emergency, the fixing cords 17 are broken by appliance of predetermined forces to the

levers

31 and 41 and the fixation to the counterweight 10 is released.

Next , the motion of the braking device 20 of the hoisting machine 11 as structured above will be explained.

Figure 3 is an elevation for explaining the motion of opening and closing of the braking device in accordance with the first embodiment of the present invention.

In the case where the braking device 20 is operated and the hoisting machine 11 is in a braked state, i.e. in the state where the electromagnet inside the casing 27 of the electromagnet is not excited, as shown in Figure 2, the brake arms 23 are braking rotation of the brake drum 21 by pressing the brake shoes 22 to the brake drum 21 with the force of the brake springs 24. Here, normal ascent and descent of the elevator car 4 is performed by release of the braking device 20, as described below. In Figure 3, it is shown that the plunger 28 is pressed downward by excitation of the electromagnet inside the casing 27 of the electromagnet. As a result of this, the brake lever 26, which abuts on the plunger head 28a, pivots by being pressed by the plunger head 28a with the brake lever pin 26a as its center; and the force of the plunger 28 is amplified and transmitted to the brake arms 23 via the bolt 25. The brake arm 23 pivots against the force of the brake springs 23 with the brake arm pins 23a as their centers, and releases brake of the braking device 20 by separating the brake shoes 22 from the brake drum 21. During normal ascent and descent of the elevator car 4, the first brake-releasing lever 31 and the second brake-releasing lever 41 travel synchronously with the travel of the counterweight 10. For this reason, the

operation ropes

33 and 43 and the

pulleys

32 and 42 which are constantly fixed to the

levers

31 and 41 move synchronously with the travel of the

levers

31 and 41.

Next, the motion of the brake-releasing mechanism of the braking device 20 will be explained.

Figure 4 is an elevation for explaining the motion of the first brake-releasing mechanism in accordance with the first embodiment of the present invention.

In Figure 4, it is shown that the first brake-releasing mechanism 30 releases the braking device 20 by actuating the first brake-releasing lever 31 by pulling down the part of the rope which is at the side opposite to the part of the first operation rope 33 where the first brake-releasing lever 31 is fixed. By pulling the first operation rope 33 as aforementioned, the pulley 32 rotates in the direction shown by the arrow in Figure 4, and the connection part of the first brake-releasing lever 31 and the first operation rope 33 is pulled up. According to this, the first brake-releasing lever 31 pivots with the supporting point supported by the supporting-point base 29 of the casing 27 of the electromagnet as the center, and the first releasing-lever coupling part 34 presses the plunger head 28a downward. The subsequent motion is the same as the brake releasing motion of the braking device 20; the force of the plunger 28 is transmitted to the brake arms 23 via the brake levers 26, and releasing of brake of the braking device 20 is performed by resisting the brake springs 24. When actuating the first brake-releasing lever 31, the fixing cord 17 which fixes the first brake-releasing lever 31 to the counterweight 10 is broken, and operation of the first brake-releasing lever 31 becomes possible by pulling the first operation rope 33.

Figure 5 is an elevation for explaining the motion of the second brake-releasing mechanism in accordance with the first embodiment of the present invention.

In Figure 5, it is shown that the second brake-releasing mechanism 40 releases the braking device 20 by actuating the second brake-releasing lever 41 by pulling down the part of the rope which is at the side of the second operation rope 43 onto which the second brake-releasing lever 41 is fixed. By pulling the second operation rope 43 as aforementioned, the connection part of the second brake-releasing lever 41 and the second operation rope 43 is pulled down. According to this, the second pulley 42 rotates in the direction shown by the arrow in Figure 5. In accordance with this, the second brake-releasing lever 41 pivots with the end part of the second brake-releasing lever 41 which abuts on the supporting-point base 29 of the casing 27 of the electromagnet as the supporting point, and the second brake-releasing lever coupling part 44 presses the plunger head 28a downward. The subsequent motion is the same as the normal brake releasing motion of the braking device 20 and the first brake-releasing mechanism 30; the force of the plunger 28 is transmitted to the brake arms 23 via the brake levers 26, and releasing of brake is performed by resisting the brake springs 24. When actuating the second brake-releasing lever 41, the fixing cord 17, which fixes the second brake-releasing lever 41 to the counterweight 10, is broken, and operation of the second brake-releasing lever 41 becomes possible by pulling the second operation rope 43.

Next, the cases where each of the first brake-releasing mechanism 30 and the second brake-releasing mechanism 40 are actually used will be explained.

In the case where the counterweight 10, onto which the braking device 20 is mounted, is heavier than the elevator car 4, the first brake-releasing mechanism 30 is selected; and releasing of brake of the braking device 20 is performed by usage of the first brake-releasing lever 31. Inversely, in the case where the counterweight 10 is lighter than the elevator car 4, releasing of brake of the braking device 20 is performed by usage of the second brake-releasing lever 41.

Normally, depending on the imbalance between the counterweight 10 and the elevator car 4 according to the change in the number of passengers embarking and disembarking the elevator car 4, cases where the counterweight 10 becomes heavier than the elevator car 4, and inversely, cases where the counterweight 10 becomes lighter than the elevator car, 4 occur. For this reason, when the brake of the braking device 20 is released, cases where the counterweight 10 moves up, and where the counterweight 10 moves down occur, depending on the situation of the number of passengers.

The first brake-releasing lever 31 is used in cases where the counterweight 10 is heavier than the elevator car 4, i.e. in cases where the counterweight 10 moves downward when the braking device 20 is released. Here, if the first brake-releasing lever 31 is actuated, an upward force resisting the force of the lever 31 pressing the plunger head 28a is exerted to the supporting-point base 29, which supports the supporting point of the lever 31. For this reason, in cases where the counterweight 10 is lighter than the elevator car 4, i.e. in cases where the counterweight 10 moves upward when the braking device 20 is released, if the first brake-releasing lever 31 is used, the pressing force to be exerted to the plunger head 28a by the first brake-releasing lever 31 escapes because the counterweight 10 moves upward, which is the same as the force exerted to the supporting-point base 29, and cases where releasing of brake of the braking device 20 cannot be performed accurately occur.

Furthermore, the cases where the second brake-releasing lever 41 is to be used are cases where the counterweight 10 is lighter than the elevator car 4, i.e. cases where the counterweight 10 moves upward when the braking device 20 is released, as aforementioned. Inversely to these cases, if the second brake-releasing lever 41 is used when the counterweight 10 moves downward when the braking device 20 is released, the lever 41 acts with the end part of the brake lever 41 abutting on the supporting-point base 29 as the supporting point so as to press the plunger head 28a that is coupled with a middle part of the lever 41, however, at this time, if the counterweight 10 moves downward, the force of the lever 41 to press the plunger head 28a escapes, and cases where releasing of brake of the braking device 20 cannot be performed accurately occur.

Accordingly, which of the first or the second brake-releasing mechanisms to use is selected as mentioned above, depending on the situation of the number of passengers in the elevator car 4.

Next: the first pulley 32 and the second pulley 42 used in the brake-releasing mechanism of the braking device 20 of the hoisting machine 10 in accordance with the first embodiment of the present invention are of iron; however, these can also be of synthetic resin, which is lighter in weight. Furthermore, the first operation rope 33 and the second operation rope 43 can be of synthetic fiber, which is lighter in weight compared to those of iron. If the moments of inertia of the pulleys and the operation ropes are large, the forces exerted by the operation ropes on the brake-releasing levers, which move synchronously with the counterweight 10 also become large during normal acceleration and deceleration of the elevator, thus causing disturbance upon the brake-releasing mechanism. For this reason, it is possible to lessen the possibility of faulty operation of the brake-releasing mechanism by using synthetic-resin pulleys and synthetic-fiber operation ropes, and making them lighter in weight compared to those of iron.

According to the aforementioned first embodiment, the following effects can be obtained:

Since the braking device 20, which is mounted on the counterweight 10 with the hoisting machine 11, has brake-releasing mechanisms that comprise a brake-releasing lever, an operation rope and a pair of pulleys, in the event that electrical control to release brake of the braking device 20 becomes impossible in an emergency, it is possible to mechanically release brake of the braking device 20 from the ground, and there is no necessity for a maintenance worker to go to the place where the hoisting machine 11 mounted on the counterweight has stopped to release brake of the braking device 20; thus it is possible to rescue passengers by moving the elevator car 4 to the nearest floor with facility and without fail.

Also, as the brake-releasing mechanism is comprised of two sets - a first and a second - brake-releasing mechanisms, in both the cases where the counterweight 10 is heavier than the elevator car 4 and where it is lighter than the elevator car 4, it is possible to select and use the brake-releasing mechanism suitable for the case, and it is possible to release brake of the brake-releasing device 20 stably without being affected by the imbalance between the weights of the counterweight 10 and the elevator car 4.

Furthermore, the first brake-releasing lever 31 and the second brake-releasing lever 41 both use a part of the casing 27 of the electromagnet as a supporting-point base 29 and make it work as a supporting point; the supporting-point base 29 is close to the plunger head 28a that is the working point, and is preferable in position as a supporting point. Moreover, the casing 27 of the electromagnet and the frame body 14 of the counterweight 10 are strongly-structured by nature and also high in strength, so it is suitable for a supporting point.

Moreover, at normal ascent and descent of the elevator car 4, since the first brake-releasing lever 31 and the second brake-releasing lever 41 are both fixed to the counterweight 10 by means of the fixing cord 17, it is possible to control impact of disturbance caused by moments of inertia of the pulleys and the operation ropes.

Second Embodiment

As shown in Figure 6, in the second embodiment of the present invention, in the connection part of the first brake-releasing lever 31 and the first operation rope 33, and the connection part of the second brake-releasing lever 41 and the second operation rope 43, there are provided pierced holes (not shown) respectively on the lever sides thereof. The operation ropes are passed through each of the pierced holes; the levers and the operation ropes are not in contact with each other, so the operation ropes do not move synchronously with the brake-releasing levers during normal ascent and descent of the elevator car 4, inversely to the first embodiment. Accordingly, in the first embodiment the counterweight 10 and the brake-releasing levers are fixed by means of a fixing cord 17, however in the second embodiment, a fixing cord 17 is not used.

As a connecting means for connecting the brake-releasing levers and the operation ropes in the cases where a brake-releasing mechanism is to be used, actuating pieces 18 are fixed on both the first operation rope 33 and the second operation rope 43. Normally, the actuating piece 18 fixed on the side of the first operation rope 33 is arranged near the first pulley 32 provided in a lower part of the hoistway 1, and the actuating piece 18 fixed on the side of the second operation rope 43 is arranged near the second pulley 42 provided in an upper part of the hoistway 1. In the cases where the brake-releasing mechanisms are actually operated, the levers and the actuating pieces 18 become coupled by operating and moving each of the operation ropes in the direction the levers are to be moved respectively, thus enabling operation of the levers. The other structures and the motions are the same as the first embodiment, so the same numerals are given to the same parts or the corresponding parts, thus repeated explanation will be omitted.

In the second embodiment, actuating pieces 18 are needed because the brake-releasing levers and the operation ropes are not constantly fixed, however, as the brake-releasing levers and the operation ropes are not in contact with each other during normal ascent and descent of the elevator car 4, it is advantageous in the point that there is no impact caused by moments of inertia from the pulleys nor from the operation ropes. In addition to this, the same effects as the first embodiment can be attained.

In the above-mentioned embodiments, an elevator system in accordance with the present invention wherein the hoisting machine 11 is mounted on the counterweight 10 has been explained as an example, however, this can also be similarly applied to cases in which the hoisting machine 11 is mounted on the elevator car 4.

Industrial Applicability

As aforementioned, the elevator system in accordance with the present invention enables rescue of passengers by the maintenance worker's releasing brake of the braking device from the ground mechanically and moving the elevator car to the nearest floor, in the event that electric control of opening and closing of the braking device becomes impossible when the elevator stops between floors due to malfunction. Also, as two sets - a first and a second -brake-releasing mechanisms are comprised, it is possible to perform a more stable releasing operation of the braking device with facility and also without fail by selecting the brake-releasing device suited to the situation, regardless of the number of passengers in the elevator car. Accordingly, the present invention is useful as an elevator wherein security is improved in emergencies and space-saving is aimed by mounting the hoisting machine on the elevator car or the counterweight.

Claims

An elevator system characterized in comprising:

an elevator car which travels through a hoistway;

a counterweight which travels through said hoistway in the direction opposite to said elevator car;

a hoisting machine mounted on either of said elevator car or said counterweight;

a main rope wound around a drive sheave of said hoisting machine and suspending said elevator car and said counterweight;

a braking device which is provided on said hoisting machine; which brakes said hoisting machine by means of brake springs; and which releases brake of said hoisting machine by resisting said brake springs by means of an excited electromagnet; and

a brake-releasing mechanism which is provided separately from said braking device, and which releases brake of said braking device by mechanically resisting said brake springs.
The elevator system according to claim 1, characterized in that said brake-releasing mechanism comprises:

brake-releasing levers for retracting said brake springs and releasing brake of said braking device;

operation ropes which are wound around a pair of pulleys that are each arranged in a part higher and lower than the travel area of either of said elevator car or said counterweight, and which are stretched in a loop shape, for operating said brake-releasing levers; and

connection means for connecting said brake-releasing levers with said operation ropes.
The elevator system according to claim 2, characterized in that a supporting point of said brake-releasing levers is supported by a casing of an electromagnet fixed on said elevator car or a frame of said counterweight.
The elevator system according to claim 2, characterized in that said brake-releasing mechanism comprises a first and second set of brake-releasing mechanisms, and in comprising:

a first brake-releasing mechanism comprising a pair of first pulleys, a first operation rope and a first brake-releasing lever, wherein brake of said braking device is released by pulling up said first operation rope; and

a second brake-releasing mechanism comprising a pair of second pulleys, a second operation rope and a second brake-releasing lever, wherein brake of said braking device is released by pulling down said second operation rope.
The elevator system according to claim 4, characterized in that:

both of said first and second brake-releasing levers use as a supporting point thereof said casing of electromagnet; said first brake-releasing lever has a first releasing-lever supporting point thereof supported by said casing of electromagnet; and

said second brake-releasing lever has a second releasing-lever supporting point thereof abutted on said casing of electromagnet.
The elevator system according to claim 4 or claim 5, characterized in that:

said braking device is comprised so as to release brake of said hoisting machine by resisting said brake springs, by drive of a pushing body by an excited electromagnet;

said first and second brake-releasing levers each have a first releasing-lever coupling part and a second releasing-lever coupling part respectively which couple with said pushing body; and

brake of said braking device is released by drive of said pushing body by said first brake-releasing coupling part or said second brake-releasing coupling part.
The elevator system according to claim 6, characterized in that:

said first brake-releasing coupling part is coupled with said pushing body with said pushing body passed through a through hole provided on said first brake-releasing lever; and

said second brake-releasing coupling part is rotatably connected with said pushing body.
The elevator system according to any one of claims 2 through 7, characterized in that said pulleys are of synthetic resin and said operation ropes are of synthetic fiber.
The elevator system according to any one of claims 2 through 8, characterized in comprising fixing means for maintaining said brake-releasing levers in a state fixed to said elevator car or said frame body of counterweight at normal travel of said elevator car, and for releasing fixation of said brake-releasing levers by exertion of a predetermined force to said operation ropes in the case where said brake-releasing levers are to be actuated by said operation ropes.