GB2211809A

GB2211809A - A braking apparatus for a passenger conveyor

Info

Publication number: GB2211809A
Application number: GB8825607A
Authority: GB
Inventors: Hayashi Nakazawa
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1987-11-02
Filing date: 1988-11-02
Publication date: 1989-07-12
Anticipated expiration: 2008-11-02
Also published as: GB2211809B; GB8825607D0; HK21692A; JPH01122893A; JPH0717340B2

Abstract

A braking apparatus for a passenger conveyor which has a series of steps, a step driving sprocket, a driven sprocket (3) to drive the step driving sprocket, a driving sprocket (2) of a driving machine (1), and a driving chain (4) to drive the driven sprocket (3) from the driving sprocket (2) comprises a braking member (13) provided to face and be engageable with the outer peripheral portion of the driven sprocket (3) to brake the driven sprocket when the braking member is rotated, a guide shoe (9) slidably mounted on said driving chain (4) and supported by a lever (8) to keep a constant position with the help of the driving chain, a first link (16) pivotally mounted on the guide shoe, one end of the first link being connected to a pin (20) actuated by a solenoid (18) through a second link (17) and the other end being pivotally connected to the braking member through a third link (19) whereby the braking member (13) is rotated so as to engage with the drive sprocket (3) to brake it, when the driving chain is broken or slackened or when the pin (20) is pulled by the solenoid. <IMAGE>

Description

A BRAKING APPARATUS FOR A PASSENGER CONVEYOR The present invention relates to a braking apparatus for a passenger conveyor, such as an escalator and a moving walkway, and more particularly to a braking apparatus suitable for stopping the passenger conveyor safety even at the time when a driving chain breaks or at any other unusual incident or accident.

In general, a passenger conveyor comprises a series of steps, a step chain mounting thereon the series of steps at a constant interval, a step chain sprocket provided on a main drive shaft to drive the series of steps through driving of the step chain, a driven sprocket fixed to the step chain sprocket to rotate the latter, a driving sprocket mounted on an output shaft of a driving machine in an upper machine room, and a driving chain engaged with the driven sprocket and the driving sprocket so as to drive the former by the latter. A driving motor shaft of the driving machine has an electromagnetic brake mounted thereon, and the driving motor shaft is automatically braked when the motor is interrupted to supply electric current thereto.

In a conventional braking apparatus in which brake is effected when the driving chain is broken, a braking member having a counterweight portion is provided to catch an outer peripheral portion of the driven sprocket thereby to brake the step chain sprocket when the driving chain is broken. A guide shoe is put on the driving chain for detecting the breaking of the driving chain. The guide shoe is connected to a rotatable lever supported to a stationary, and lowered while rotating in a circle with a rotating radius of a distance between supporting points of the rotatable lever when the driving chain is broken.

The braking member and the guide shoe are pivotally connected by a link, and the braking member is rotated when the guide shoe is lowered upon breaking of the driving chain to catch the outer peripheral portion of the driven sprocket whereby the step chain sprocket is braked. An actuator for actuating a switch is fixed to the rotatable lever around a rotation center of the lever.

The actuator pushes the switch when the shoe is lowered upon breaking of the driving chain, whereby electric power source of a driving motor for driving the driving sprocket is interrupted, so that the driving sprocket is stopped.

In order to improve further the safety of the passenger conveyor, on the other hand, it has been studied to detect such an unusual case other than the breaking of the driving chain as the passenger conveyor moving at an overspeed or moving suddenly in the reverse direction in the course of operation, for instance by means of a detecting device, and to brake the main driving shaft mounting thereon the step chain sprocket directly on the basis of an electric signal on the device. In this relation, such an apparatus of making a braking apparatus operate electrically as described in Japanese Patent Laid Open No. 295990/1986 has been proposed. In this apparatus, a link is provided one end of which is pivotally connected to a link mechanism connecting the guide shoe and the braking member and the other end is pivotally supported by a retaining rotatable lever.The lever is shaped in a L-letter and rotatably supported by a stationary at the bent portion. At one end of the lever, a spring is provided so that the other end of the lever is pressed on the stationary thereby to rotatably retain one end of the above-mentioned link. At an extraordinary time, the retaining rotatable lever is released upward by a solenoid provided to press the lever against the spring so as to remove the holding of the link.

The above-mentioned system described in the Japanese Patent Laid-Open No. 295990/1986, however, has problems that, since the retaining rotatable lever is retained by force of the spring, the vibration of the driving chain affects the retaining rotatable lever through the link and makes it unstable at the time of a normal operation, and that since the stroke of the solenoid is limited, the amount of upward motion of the retaining rotatable lever is restricted and consequently the release of the lever becomes unstable at an extraordinary time.

An object of the invention is to provide a braking apparatus for a passenger conveyor, which is highlyreliable and simple in construction and can brake a main driving shaft of the passenger conveyor without failure not only when a driving chain for driving the main driving shaft is broken, but also when any other unusual states take place in the passenger conveyor.

In a braking apparatus for a passenger conveyor comprising a main driving shaft of the passenger conveyor, a driven sprocket mounted on the main driving shaft, a driving sprocket mounted on an output shaft of a driving machine, and a driving chain engaged with both the driven sprocket and the driving sprocket for driving the driven sprocket through rotation of the driving sprocket, the braking apparatus according to the present invention characterized by comprising a braking member disposed so as to face the driven sprocket and engageable with the driven sprocket, a guide shoe mounted on the driving chain for detecting breaking or slackening of the driving chain, a first link pivotally mounted on the guide shoe, one end of the first link being connected, through a second link, to a pin actuated by a solenoid so as to disconnected from the second link by operation of the solenoid, the other end of the first link to the braking member through a third link so as to cause the braking member to engage with the driven sprocket when the third link is moved, and a rotatable lever pivotally linked both to the guide shoe and a stationary pivot so as to support the guide shoe and so that the shoe is prevented to move downwards by the lever and the driving chain, whereby the braking member is moved by the first and third links to engage with the driven sprocket when the driving chain is broken or when the pin is disconnected from the second link by the solenoid.

The present invention will now be described in greater detail by way of examples with reference to the accompanying drawings, wherein Fig. 1 is a schematic diagram of a passenger conveyor; Fig. 2 is a side view of an embodiment of a braking apparatus for the passenger conveyor according to the present invention; Fig. 3 is a plane view of a part of the braking apparatus of Fig. 2; Fig. 4 is a side view of the braking apparatus which is operated upon breaking of a driving chain; Fig. 5 is a view taken along a line V-V of Fig. 4 and showing a breaking member engaged with a sprocket; and Fig. 6 is a side view of the braking apparatus which is operated upon an unusual condition other than the breaking of the main driving chain.

In Fig. 1 showing a general construction of a passenger conveyor, the conveyor comprises a series of steps 7, a step chain 6 provided with the series of steps 7 and arranged endlessly, a step chain sprocket 5 which is mounted on a main drive shaft 31 and on which the step chain 6 is wound thereby driving the step chain 6, a main drive shaft sprocket or driven sprocket 3 provided on the main drive shaft of the step chain sprocket 5, a driving machine 1 settled in an upper machine room and provided with an output shaft sprocket or driving sprocket 2 mounted on the output shaft of the driving machine 1, and a driving chain 4 engaged with both the driven sprocket 3 and the driving sprocket 2 and driving the former sprocket 3 with a driving force of the driving sprocket 2. The driving machine 1 is provided with a shaft of a motor for driving the output shaft. On the shaft of the motor, an electromagnetic brake is provided, and the brake is so constructed that braking is automatically effected when electric current of the motor is interrupted.

The passenger conveyor is provided with a braking apparatus illustrated in Figs. 2 to 6 which is an embodiment of the present invention.

The braking apparatus for the passenger conveyor can stop the movement of the series of steps 7 upon breaking of the above-mentioned driving chain 4 or occurrence of an unusual condition of the passenger conveyor such as overspeed of the conveyor or a sudden movement of the steps in the reverse direction in the course of operation.

In Figs. 2 and 3, the driving chain 4 for driving the step chain sprocket 5 is engaged with the driven sprocket 3 and driven by the driving sprocket 2. On the driving chain A between the driven sprocket 3 and the driving sprocket 2, a guide shoe 9 is mounted. The guide shoe 9 is pivotally mounted on a rotatable lever 8 pivotally mounted on a stationary 21. A first link 16 is pivotally mounted the guide shoe 9 at a middle portion of the first link 16 in its length direction. The lever 8 and the first link 16 each are pivotal about a pin 12.

One end of the first link 16 is linked to one end of a second link 17, the other end of which is pivotally held by a pin 20 horizontally disposed. The pin 20 is mounted on and actuated by a solenoid 18 to move axially so that the second link 17 supported by the pin 20 is disconnected from the pin 20. The other end of the first lever 16 is connected to a braking member 13 through a third link 19. The braking member 13 is pivotally mounted on a pin 143 provided on a projection 142 of a stopper 14. The third link 19 is linked to the braking member 13 at a portion spaced from the pin 143 so that the braking member 13 is rotated clockwise by the third link 19. The braking member 13 has a counterweight portion 131 at one end thereof and a fork portion 132 at the other end. The counterweight portion 131 serves to cause the braking member 13 to rotate clockwise.The fork portion 132 of the braking member 13 has a groove, puts a sprocket tip portion therein, as shown in Fig. 5, and grips it thereby braking the driven sprocket 3. The stopper 14 which is secured to a stationary 15 has a shoulder 141 for restricting the movement of the braking member 13.

A switch 10 secured to the stationary 21 is actuated by an actuator 11 secured to the lever 8 to move together therewith.

In an ordinary condition of the passenger conveyor as shown in Fig. 2, the driving chain 4 is in tension, so that the guide shoe 9 is held at a constant position.

The second link 17 is held by the pin 20. In this condition, the braking member 13 is as shown in Fig. 2.

The fork portion 132 of the braking member 13 is separated from the driven sprocket 3, which is in a condition that braking is not effected.

If the driving chain 4 is broken as shown in Fig. 4, the driving chain 4 can not support the shoe 9, so that the shoe 9 moves downwards in a circle with a rotational radius of a distance between the link joints of the lever 8, as shown by an arrow. The movement of the shoe 9 causes the braking member 13 to rotate in a direction shown by an arrow A. The tip of the braking member 13 holds the sprocket peripheral portion as shown in Fig. 5.

The braking member 13 is rotated by the driven sprocket 3 in a direction of an arrow B shown in Fig. 4, but the movement of the braking member 13 is stopped by the shoulder 141 of the stopper 14, whereby the rotation of the driven sprocket 3 is stopped, which causes the series of steps to stop the movement thereof.

Further, the downwards movement of the shoe 9 cause the actuator 11 to rotate unticlockwise, whereby the switch 10 is operated to put on, and interrupt the electric current to the motor of the driving machine 1.

In a condition of the passenger conveyor wherein the driving chain 4 is in order and any other unusual condition such as overspeed takes place in the passenger conveyor, as shown in Fig. 6, the solenoid 18 is actuated by electric signal from a detector for detecting such an unusual condition to pull horizontally and axially the pin 20 so as to cause the pin 20 to disengage with the second link 17. One end of the second link 17 disengaged with the pin 20 moves downwards as shown by an arrow C, which causes the first link 16 to rotate about the pin 12 as shown by arrows D, while the shoe 9 is kept by the driving chain 4 at a constant position. The rotation of the first link 16 causes the braking member 13 to rotate in the direction shown by the arrow A through the third link 19. This movement of the braking member 13 causes the braking member 13 to grasp the circumferential tip portion of the driven sprocket 3, whereby the rotation of the sprocket 3 is braked as previously mentioned.

According to the embodiment, the operation of the braking apparatus is not affected by the vibration of the driving chain 4, since the second link 17 is supported or released by the pin 20 being moved horizontally, and a highly-reliable braking apparatus is obtained since the release is effected without fail.

According to the present invention, as described above, a link mechanism disengaged by the excitation of the solenoid and moving in linkage to the braking member is provided. Therefore the main driving shaft can be braked without fail also in extraordinary cases other than the breaking of the driving chain, and thus a highlyreliable braking apparatus can be furnished.

Claims

CLAIMS:

1. A braking apparatus for a passenger conveyor which is equipped with a driving chain connecting a sprocket of an output shaft of a driving machine and a sprocket of a main driving shaft, said braking apparatus comprising a guide shoe detecting the breaking or slacking of said driving chain and a braking member moving in linkage to said guide shoe to brake the rotation of the sprocket of the said main driving shaft, a first link supported pivotally by said guide shoe and a second link having an end part supported pivotally by one end of said first link and the other end part supported by a support element provided on a solenoid so that it can be disengaged from the support element when the solenoid is excited, and a third link provided at the other end of the said first link and moving in linkage to said braking member, whereby said second link is disengaged from the said support element by the excitation of said solenoid and thereby said braking member is made to brake the rotation of the sprocket of said main driving shaft.

2. A braking apparatus according to Claim 1, wherein said support element is constructed of a pin which is moved horizontally and axially by the excitation of said solenoid.

3. A braking apparatus for a passenger conveyor which has a series of steps, a step chain mounting thereon said series of steps and arranged endlessly, a step chain sprocket for driving said step chain, a driven sprocket provided so as to rotate said step chain sprocket, a driving sprocket, and a driving chain engaged with both said driven sprocket and said driving sprocket for driving said driven sprocket by said driving sprocket, said braking apparatus comprising a braking member facing an outer peripheral portion of said driven sprocket and being engageable with said outer peripheral portion of said driven sprocket through rotation of said braking member, a guide shoe mounting on said driving chain for detecting breaking or slacking of said driving chain, a lever one end of which pivotally supports said guide shoe to keep a constant position thereof with the help of said driving chain, the other end is pivotally supported by a stationary, a first link pivotally mounted on said guide shoe at a middle portion of its length, one end of said first link being pivotally connected to a second link which is pivotally supported by a fixed pin actuated by a solenoid so as to disengaged from said second link and the other end being pivotally connected to said braking member through a third link which is pivotally connected to said first link and said braking member, whereby said braking member is rotated to engage with said driven sprocket thereby to brake the rotation of said step chain sprocket when said driving chain is broken or slackened or when said solenoid actuates said pin to disengage said second lever.

4. A braing apparatus for a passenger conveyor according to claim 3, wherein said guide shoe has a pin, and said lever and said first link are pivotally connected to said guide shoe by said pin.

5. A braking-apparatus for a passenger conveyor according to claim 4, wherein said lever is provided with an actuator, which actuates a switch for controlling a power source of said driving sprocket when said guide shoe detects the breaking or slackening of said driving chain.

6. A braking apparatus for a passenger conveyor according to claim 3, wherein said braking member is rotatably mounted on a stationary member having a stopping means, said braking member having a counterweight portion and a fork portion having a groove therein and catching the peripheral portion of said driven sprocket when braking, rotation of said braking member catching said peripheral portion of said driven sprocket is stopped by said stopping means of said stationary member mounting thereon said braking member.

7. A braking apparatus for a passenger conveyor according to claim 3 wherein said pin engageable with said second link is mounted on said solenoid so that said pin is horizontally and axially pulled to disengage said second link from said pin when said solenoid is energized.

8. A braking apparatus for a passenger conveyor constructed substantially as herein described with reference to and as illustrated in Figs. 2 to 6 of the accompanying drawings.