METHOD AND PASSENGER CONVEYOR

Abstract

A method for controlling a passenger conveyor, which passenger conveyor includes an endless band of conveying elements, the endless band including an inclined conveying section; a drive shaft arranged to drive the endless band of conveying elements when rotated; a motor for rotating the drive shaft; a first sensing arrangement for sensing a rotation speed of the motor; a brake activatable to act directly on the drive shaft or an element fixedly connected to it for stopping rotation of the drive shaft; and a control system. The method includes rotating the drive shaft with the motor; and sensing rotation speed of the motor with the first sensing arrangement. The passenger conveyor includes a second sensing arrangement for sensing rotation speed of the drive shaft, and the method includes sensing rotation speed of the drive shaft with the second sensing arrangement; detecting deviation between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof; and activating the brake for stopping rotation of the drive shaft if deviation, in particular deviation meeting predefined criteria, is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof, wherein said multifold equals to the rotation speed of the drive shaft multiplied with a preset factor n, wherein n preferably equals to transmission ratio between the drive shaft and the motor. A passenger conveyor implementing the method is also disclosed.

Claims

1. A method for controlling a passenger conveyor, the passenger conveyor comprising: an endless band of conveying elements, the endless band comprising an inclined conveying section; a drive shaft arranged to drive the endless band of conveying elements when rotated; a motor for rotating the drive shaft; a first sensing arrangement for sensing a rotation speed of the motor; a brake activatable to act directly on the drive shaft or an element fixedly connected to the drive shaft for stopping rotation of the drive shaft; and a control system, wherein the method comprises: rotating the drive shaft with the motor; and sensing a rotation speed of the motor with the first sensing arrangement, wherein the passenger conveyor comprises a second sensing arrangement for sensing a rotation speed of the drive shaft, and wherein the method comprises: sensing the rotation speed of the drive shaft with the second sensing arrangement; detecting a deviation meeting a predefined criteria between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof; and activating the brake for stopping the rotation of the drive shaft if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof, wherein said multifold equals to the rotation speed of the drive shaft multiplied with a preset factor n, wherein n equals to a transmission ratio between the drive shaft and the motor.

2. The method according to claim 1, wherein said detecting comprises comparing a frequency of the motor with a frequency of the drive shaft.

3. The method according to claim 1, wherein said detecting comprises obtaining said frequency of the motor and the frequency of the drive shaft from signals received from the first sensing arrangement and the second sensing arrangement, respectively.

4. The method according to claim 1, wherein the method further comprises stopping the rotation of the motor if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof.

5. A passenger conveyor comprising: an endless band of conveying elements, the endless band comprising an inclined conveying sections; a drive shaft arranged to drive the endless band of conveying elements when rotated; a motor for rotating the drive shaft; a first sensing arrangement for sensing a rotation speed of the motor; a brake activatable to act directly on the drive shaft or an element rigidly fixed thereon for stopping rotation of the drive shaft; a control system; and a second sensing arrangement for sensing a rotation speed of the drive shaft, wherein the control system is configured to detect a deviation meeting a predefined criteria between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof, and to activate the brake for stopping rotation of the drive shaft if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof, wherein said multifold equals to the rotation speed of the drive shaft multiplied with a preset factor n, wherein n equals to a transmission ratio between the drive shaft and the motor.

6. The passenger conveyor according to claim 5, wherein the control system is configured to compare a frequency of the motor with a frequency of the drive shaft for detecting said deviation.

7. The passenger conveyor according to claim 5 wherein the control system is configured to stop the rotation of the motor if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof.

8. The method according to claim 1 wherein the motor is connected with the drive shaft with a transmission, the transmission comprising one or more gear wheels and/or a drive chain for transmitting rotation between an output shaft of the motor and the drive shaft.

9. The method according to claim 1, wherein the element fixedly connected with the drive shaft is a wheel coaxial with the drive shaft.

10. The method according to claim 9, wherein said wheel fixedly connected with the drive shaft is a drive wheel rotatable by the drive shaft, and arranged to drive the endless band when rotated, or said wheel fixedly connected with the drive shaft is a braking wheel, fixedly connected with the drive shaft in addition to a pair of drive wheels.

11. The method according to claim 9 wherein the brake is a gripping device actuatable to grip said wheel fixedly connected with the drive shaft for stopping rotation thereof.

12. The method according to claim 1 wherein, the second sensing arrangement is arranged to generate and send to the control system signals having a frequency proportional to the rotation speed of the drive shaft.

13. The method according to claim 1 wherein the second sensing arrangement for sensing a rotation speed of the drive shaft comprises one or more encoders.

14. The method according to claim 1, wherein the second sensing arrangement comprises a rotatable member engaging the drive shaft such that the rotatable member is rotatable by the drive shaft.

15. The method according to claim 14, wherein the rotatable member is connected to the drive shaft such that they share a rotational axis, the rotatable member being fixed to an axial end face of the drive shaft.

16. The method according to claim 14, wherein the rotatable member is a wheel leaning against a rim of the drive shaft, the rotational axis of said wheel and the rotational axis of said shaft extending parallel at a distance from each other, said wheel being a friction wheel frictionally engaging the rim of the drive shaft.

17. The method according to claim 2, wherein said detecting comprises obtaining said frequency of the motor and the frequency of the drive shaft from signals received from the first sensing arrangement and the second sensing arrangement, respectively.

18. The method according to claim 2, wherein the method further comprises stopping rotation of the motor if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof.

19. The method according to claim 3, wherein the method further comprises stopping rotation of the motor if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof.

20. The passenger conveyor according to claim 6, wherein the control system is configured to stop rotation of the motor if the deviation is detected between the rotation speed of the motor and the rotation speed of the drive shaft or a multifold thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the following, the present invention will be described in more detail by way of example and with reference to the attached drawings, in which

[0041] FIG. 1 illustrates a preferred embodiment of a passenger conveyor according to the invention.

[0042] FIG. 2 illustrates preferred details of the passenger conveyor of FIG. 1 from above.

[0043] FIG. 3 illustrates the passenger conveyor of FIG. 1 from a side.

[0044] FIG. 4 illustrates preferred details one preferred configuration for the second sensing arrangement.

[0045] FIG. 5 illustrates preferred connections between the first sensing arrangement, the second sensing arrangement, the brake and the motor of the passenger conveyor of FIG. 1.

[0046] The foregoing aspects, features and advantages of the invention will be apparent from the drawings and the detailed description related thereto.

DETAILED DESCRIPTION

[0047] FIG. 1 illustrates a passenger conveyor 1, in particular an escalator, comprising an endless band 2 of conveying elements 2a, the band 2 comprising an inclined conveying section I for conveying passengers standing on the conveyor elements 2a at an inclined angle upwards or downwards. The passenger conveyor 1 comprises a driven end D wherein the equipment for driving the passenger conveyor are placed. The passage of the band 2 of the conveying elements 3 is also diverted in the driven end D.

[0048] In the presented preferred embodiment, the passenger conveyor 1 is an escalator where the conveying elements 3 are connected to each other by two endless traction members 11, which is in the presented case are chains, as presented more precisely in FIGS. 2 and 3.

[0049] As visible in FIGS. 2 and 3, the passenger conveyor 1 comprises a drive shaft 3 arranged to drive the one or more traction members 11 and thereby the endless band 2 when rotated. The passenger conveyor 1 comprises a pair of drive wheels 10, which are in the preferred embodiment in the form of sprocket wheels, which drive wheels 10 are rotatable by the drive shaft 3, which drive wheels 10 are arranged to drive the endless band 2 when rotated, in particular directly acting on the traction members 11 and/or the conveying elements 2a thereof.

[0050] In the preferred embodiment, the drive wheels 10 are fixedly connected with the drive shaft 3.

[0051] The passenger conveyor 1 moreover comprises a motor 4 for rotating the drive shaft 3. The motor 4 is connected with the drive shaft 3 in a force transmitting manner, preferably via a transmission 9 as illustrated. The transmission 9 preferably comprises one or more gear wheels and/or a drive chain for transmitting rotation between an output shaft 4a of the motor 4 and the drive shaft 3. The transmission 9 may comprise a transmission housing 9a accommodating the aforementioned one or more gear wheels and/or a drive chain. The transmission 9 allows rotation speed of the output shaft 4a of the motor 4 and the drive shaft 3 differ, as well as provides freedom in choosing an optimal location for the motor 4. Transmission also brings components between the motor and drive shaft 3, whereby risk of failures increases, and thus in this context aspects of the invention are advantageous.

[0052] The passenger conveyor 1 moreover comprises a brake 7;7 activatable to act directly on the drive shaft 3 or an element 8;10 fixedly connected therewith for stopping rotation of the drive shaft 3. Thus, rotation of the drive shaft 3 can be stopped even in case motor 4, the brakes thereof, or the transmission 9 between the motor 4 and the drive shaft 3 fails to operate.

[0053] The passenger conveyor 1 moreover comprises a first sensing arrangement 5 for sensing a rotation speed of the motor 4; and a second sensing arrangement 6;6 for sensing rotation speed of the drive shaft 3; and a control system 9.

[0054] The method according to the invention comprises rotating the drive shaft 3 with the motor 4; and sensing rotation speed of the motor 4 with the first sensing arrangement 5, and sensing rotation speed of the drive shaft 3 with the second sensing arrangement 6;6; and detecting deviation between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof; and activating the brake 7;7 for stopping rotation of the drive shaft 3 if deviation, in particular deviation meeting predefined criteria, is detected between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof. The detecting is performed in the preferred embodiment by said control system 9.

[0055] In the aforementioned detecting, said multifold is preferably used particularly when the motor 4 indirectly drives the drive shaft 3, i.e. there is a transmission 9 between them. Said multifold preferably equals to the rotation speed of the drive shaft 3 multiplied with a preset factor n, wherein n preferably equals to transmission ratio between the drive shaft 3 and the motor 4.

[0056] Said detecting preferably comprises comparing a frequency of the motor 4 with a frequency of the drive shaft 3. Said frequency of the motor 4 and the frequency of the drive shaft 3 are obtained in the preferred embodiment from signals received from the first sensing arrangement 5 and the second sensing arrangement 6, respectively. Signals usable for this purpose can be simply generated by an encoder comprised in each of said first sensing arrangement 5 and the second sensing arrangement 6.

[0057] For enabling said comparing, the detecting preferably comprises obtaining the frequency of the motor 4 and the frequency of the drive shaft 3 from signals received from the first sensing arrangement 5 and the second sensing arrangement 6, respectively. Said obtaining can comprise processing and analyzing the signals received, if needed.

[0058] The method further comprises stopping rotation of the motor 4 if deviation, in particular deviation meeting predefined criteria, is detected between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof.

[0059] The passenger conveyor 1 according to the invention is configured to implement the method described above. The control system 12 of the passenger conveyor 1 is configured to detect deviation between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof, and to activate the brake 7;7 for stopping rotation of the drive shaft 3 if deviation, preferably deviation meeting predefined criteria, is detected between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof, wherein said multifold equals to the rotation speed of the drive shaft 3 multiplied with a preset factor n, wherein n preferably equals to transmission ratio between the drive shaft 3 and the motor 4.

[0060] In the preferred embodiment, the control system 12 is configured, preferably by aid of one or more microprocessors comprised in the control system 9, to compare a frequency of the motor 4 with a frequency of the drive shaft 3 for detecting said deviation. In the preferred embodiment, said frequency of the motor 4 and the frequency of the drive shaft 3 are arranged to be obtained from signals received from the first sensing arrangement 5 and the second sensing arrangement 6, respectively. Signals usable for this purpose can be simply generated by an encoder comprised in each of said first sensing arrangement 5 and the second sensing arrangement 6.

[0061] In the preferred embodiment, the control system 12 is configured to stop rotation of the motor 4 if deviation, in particular deviation meeting predefined criteria, is detected between the rotation speed of the motor 4 and the rotation speed of the drive shaft 3 or a multifold thereof.

[0062] In the preferred embodiment, the motor 4 is connected with the drive shaft 3 with transmission 9, the transmission 9 preferably comprising one or more gear wheels and/or a drive chain for transmitting rotation between an output shaft 4a of the motor 4 and the drive shaft 3.

[0063] As mentioned above, the brake 7,7 is activatable to act directly on the drive shaft 3 or an element 8;10 fixedly connected therewith for stopping rotation of the drive shaft 3. FIG. 2 illustrates two possible alternative positions for the brake 7,7, one shown in solid line and the other in broken line. In these alternatives, the brake 7,7 is activatable to act directly on the element 8,10 fixedly connected with the drive shaft 3, which element is in each of these cases a wheel 8 coaxial with the drive shaft 3.

[0064] According to the first preferred alternative, as illustrated in FIGS. 2 and 3, the brake 7 (drawn in solid line) is activatable to act directly on wheel 8, which is a braking wheel fixedly connected with the drive shaft 3 in addition to a pair of drive wheels 10. The braking wheel does not serve here as a drive wheel of the traction member and/or the conveying elements.

[0065] According to the second preferred alternative, as illustrated in FIG. 2, the brake 7 (drawn in broken line) is activatable to act directly on wheel 10, which is a drive wheel 10 rotatable by the drive shaft 3, in this case a sprocket wheel, which drive wheel 10 is arranged to drive the endless band 2 when rotated, in particular directly acting on a traction member 11 and/or the conveying elements 2a thereof.

[0066] The brake 7,7 is a gripping device actuatable to grip said wheel 8,10 for stopping rotation thereof, as illustrated. However, the brake could also be of some other kind, since gripping although advantageous, is not be necessary for achieving a braking action. The brake 7,7 in the form of a gripping device as illustrated, comprises two gripping members 7a, 7b between which the wheel 8, 10 extends the gripping members 7a, 7b being movable into contact with the wheel 8, 10 for braking rotation of the wheel 8, 10. The brake 7,7 in the form of a gripping device can be a floating caliber brake for instance, whereby one of the gripping members 7a,7b can be stationary relative to a body of the gripping device, for example. The brake 7,7 in the form of a gripping device is a device known as such, and used for instance in brakes systems of elevators. The brake 7,7 in the form of a gripping device can be for instance such that it comprises a spring for urging gripping members of the gripping device towards a gripping state, i.e. towards each other so that they move towards the wheel 8, 10 between them, and an actuator such as a solenoid arranged to pull against the force of the spring the gripping members of the gripping device outwards from a gripping state, i.e. outwards from each other so that they are pulled outwards from the wheel 8, 10 between them. This kind of operation principle provides a fail safe structure for the brake 7,7.

[0067] In the method and the passenger conveyor 1 according to invention, said criteria preferably, although not necessarily, comprise that the deviation exceeds a threshold amount or that one of the rotation speed of the motor 4 or the rotation speed of the drive shaft 3 or a multifold thereof is zero when the other is non-zero, for example.

[0068] In the method and the passenger conveyor 1 according to invention, determination of whether said one or more criteria are met, is performed/configured to be performed by the control system 9.

[0069] In the method and the passenger conveyor 1 according to invention, preferably additionally, although not necessarily, the control system 12 stops/is configured to stop, respectively, rotation of the motor 4 if signals are received by the control system 12 only from one of the first sensing arrangement 5 and the second sensing arrangement 6.

[0070] In the method and the passenger conveyor 1 according to invention, preferably the second sensing arrangement 6;6 for sensing a rotation speed of the shaft 3 comprises one or more encoders 6a,6b;6a,6b. Each said encoder 6a,6b;6a,6b is preferably a rotary encoder.

[0071] FIG. 2 illustrates two possible alternative configurations for the encoder 6a,6b;6a,6b of the second sensing arrangement 6;6. In each of these alternatives, the encoder 6a,6b;6a,6b of the second sensing arrangement 6;6 comprises an a rotatable member 6a;6a engaging the shaft 3 such that it is rotatable by the shaft 3. The encoder 6a,6b;6a,6b of the second sensing arrangement 6;6 moreover comprises a non-rotatable body 6b;6b on which the rotatable member 6a;6a is mounted rotatably relative to said body 6b;6b. The encoder 6a,6b;6a,6b is arranged to generate and send signals to the control system 12 indicating rotation speed of the shaft 3.

[0072] The signals of the encoder 6a,6b;6a,6b generated and sent to the control system 12 have preferably frequency proportional to the rotation speed of the drive shaft 3. The encoder 6a,6b;6a,6b can for instance comprise one or more sensors mounted on a non-rotatable body 6b;6b arranged to sense one or more features of the rotatable member 6a;6a, and to generate and send a signal to the control system, every time a feature to be sensed passes by it.

[0073] According to the first preferred alternative, as illustrated in FIGS. 2 and 4, the rotatable member 6a is a wheel leaning against a rim of the drive shaft 3, the rotational axis of said wheel 6a and said shaft 3 extending parallel at a distance from each other. Said wheel 6a is preferably a friction wheel frictionally engaging the drive shaft 3. Said friction wheel preferably has a rim comprising elastomer material, such as rubber or polyurethane, for instance. Hereby, a frictional engagement is simply implemented. The frictional engagement can be facilitated by providing an pressing mechanism for pressing the rim of the rotatable member 6a against a rim of the drive shaft 3. The mechanism can comprise one or more springs s arranged to press the rotatable member 6a against the drive shaft 3. This can be implemented such that said one or more springs s are arranged urge (preferably push or alternatively pull) the body 6b such that the rotatable member 6a is pressed against the drive shaft 3.

[0074] According to the second preferred alternative, as illustrated in FIGS. 2 and 3, the rotatable member 6a is fixed on the drive shaft 3 such that they share a rotational axis x. The rotatable member 6a is preferably fixed to an axial end face of the drive shaft 3 as illustrated in FIG. 2.

[0075] In the method and the passenger conveyor 1 according to invention, preferably the first sensing arrangement 5 for sensing a rotation speed of the motor 4 comprises one or more encoders. Different arrangements for sensing rotation speed of a motor are known and used. One widely known and used arrangements for sensing rotation speed of a motor comprises an encoder. The encoder can for instance comprise one or more sensors mounted on a stator of the motor and arranged to sense one or more features of the rotor of the motor 4, and to generate and send a signal to the control system, every time a feature to be sensed passes by it. The encoder is preferably arranged to generate and send signals to the control system 12 indicating rotation speed of the motor 4. The signals of the encoder generated and sent to the control system 12 have preferably frequency proportional to the rotation speed of the motor 4.

[0076] As illustrated in FIG. 5, it is preferable that the control system 12 is connected with the first sensing arrangement 5, the second sensing arrangement 6, for receiving signals from them, and with the brake 7,7 and the motor 4 for sending control signals to them.

[0077] It is to be understood that the above description and the accompanying Figures are only intended to teach the best way known to the inventors to make and use the invention. It will be apparent to a person skilled in the art that the inventive concept can be implemented in various ways. The above-described embodiments of the invention may thus be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that the invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.