METHOD AND APPARATUS FOR SENSING MOTION OF AN ELEVATOR CAR OR COUNTERWEIGHT

Abstract

A guide rail (1, 41, 51, 61, 71, 81) for an elevator car (82) or counterweight, wherein the guide rail (1, 41, 51, 61, 71, 81) comprises a pattern (6, 46, 56, 66, 76) formed directly on the guide rail (1, 41, 51, 61, 71, 81) and extending along the length of the guide rail (1, 41, 51, 61, 71, 81), suitable for being detected by a sensor (84).

Claims

1. A guide rail for an elevator car or counterweight, wherein the guide rail comprises a pattern formed directly on the guide rail and extending along the length of the guide rail, suitable for being detected by a sensor.

2. The guide rail of claim 1 wherein the pattern is on a surface of the guide rail which, in use, is not engaged with a guiding element of the elevator car, such as a roller or slider.

3. The guide rail of claim 1 wherein the pattern is on a recessed surface of the guide rail.

4. The guide rail of claim 1 wherein the pattern comprises a plurality of equally spaced marker regions.

5. The guide rail of claim 4 wherein the spacing between adjacent marker regions is no more than 10 mm.

6. The guide rail of claim 4 wherein each marker region comprises a depression formed in the guide rail.

7. The guide rail of claim 1 wherein the pattern comprises a relief pattern on the guide rail.

8. The guide rail of claim 1 wherein the pattern is a repeating pattern.

9. An elevator system, comprising: an elevator car or counterweight; a sensor fixed to the elevator car or counterweight; and a guide rail as claimed in claim 1, wherein the sensor is configured to detect the pattern.

10. The elevator system of claim 9 wherein the sensor is configured to determine the speed and/or the position of the elevator car or counterweight relative to the guide rail, using the sensed pattern.

11. The elevator system of claim 10 wherein the pattern comprises a plurality of equally spaced marker regions and wherein the sensor is configured to determine the speed of the elevator car by counting a number of marker regions which the sensor detects in a particular period of time, or by measuring the time period that elapses during the detection of a number of marker regions.

12. The elevator system of claim 9, wherein the sensor is a non-contact sensor, e.g. an inductive sensor, or an ultrasound detector, or an infrared detector, or an optical detector, or a diffuse-reflective detector.

13. A method of manufacture of a guide rail, comprising: applying a pattern along the length of a surface of the guide rail.

14. The method of claim 13, wherein the pattern is applied to the guide rail by stamping or indenting the surface of the guide rail using a tool with a corresponding relief pattern.

15. A method of sensing the speed of movement of an elevator car or counterweight relative to a guide rail, comprising: detecting, using a sensor, a pattern extending along the length of the guide rail; and calculating, using the sensed pattern, the speed of the elevator car or counterweight.

Description

DRAWING DESCRIPTION

[0033] Certain preferred examples of this disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0034] FIG. 1a shows a profile of a guide rail as is known in the art.

[0035] FIG. 1b shows a profile of a guide rail according to the present disclosure.

[0036] FIG. 2a shows a side view of a first example of a guide rail according to the present disclosure.

[0037] FIG. 2b shows a three-dimensional representation of the guide rail of FIG. 2a.

[0038] FIG. 3 shows schematically a method of manufacture of a guide rail according to the present disclosure.

[0039] FIG. 4 shows a second example of a guide rail according to the present disclosure.

[0040] FIG. 5 shows a third example of a guide rail according to the present disclosure.

[0041] FIG. 6 shows a fourth example of a guide rail according to the present disclosure.

[0042] FIG. 7 shows a fifth example of a guide rail according to the present disclosure.

[0043] FIG. 8 schematically shows an elevator system according to the present disclosure.

DETAILED DESCRIPTION

[0044] FIG. 1a shows the profile of a guide rail 1, as is known in the art. It can be seen from this Figure that the guide rail 1 comprises a base portion 3 that may be fixed to the hoistway wall, and extending therefrom is a rail portion comprising a first portion 2 and a second portion 4. In use there is typically a guide rail fixed along the length of two opposing sides of an elevator hoistway. An elevator car has guiding elements, e.g. rollers or sliders on two of its opposing sides, and these roll or slide along the first portion 2 of the guide rail 1, allowing the elevator car to move in the predefined direction allowed by the guide rail 1. As shown in FIG. 1a, the guide rail 1 further includes a second portion 4, which is not engaged with, or in contact with, the roller or slider of the elevator car. In this particular example the second portion 4 of the guide rail is thinner than the first portion 2 such that its surfaces are recessed with respect to the surfaces of the first portion 2.

[0045] FIG. 1b shows the profile of certain examples of a guide rail 1 as claimed. Similarly to the guide rail of FIG. 1a, the guide rail 1 of the example of FIG. 1b comprises a first portion 2, which, in use, is engaged with the rollers or sliders of an elevator car and a second portion 4 which is not engaged with, or in contact with, the rollers or sliders of the elevator car. The second portion 4 of the guide rail 1 is recessed as discussed above in relation to FIG. 1a. In addition to these features, the guide rail 1 has a pattern region 6, which is described in more detail with reference to the later Figures. In the pattern region 6, a pattern is formed directly on the surface of the second portion 4 of the guide rail 1.

[0046] FIG. 2a shows a first example of the present disclosure, and FIG. 2b shows a three-dimensional representation of this same example. Both FIGS. 2a and 2b show a small section of a guide rail 1. In this particular example, the thinner (recessed) portion 4 of the guide rail 1 includes a pattern region 6, which is made up of a number of marker regions 20, which, in this example, are recessed depressions in the guide rail 1. In this example these marker regions are square or rectangular depressions or pockets 20. It will be appreciated that other shapes are also possible such as circles, ellipses, triangles, etc.

[0047] Adjacent pockets 20 are separated by a separation distance 22. In this example the separation distances 22 between adjacent pockets 20 are all equal, so that adjacent pockets 20 are equally spaced along substantially the length of the guide rail 1. In some examples this separation distance 22 can be no more than 10 mm, more preferably no more than 5 mm, or no more than 3 mm Each pocket 20 has a certain width 24. In this example each pocket 20 has an identical width 24, (and an identical height and depth) and therefore all of the pockets are identical. In some examples the width of the pocket 20 can be no more than 10 mm, more preferably no more than 5 mm, or no more than 3 mm The depth of the pockets (depressions) 20 may be at least 0.5 mm, preferably at least 1 mm or at least 2 mm The depth of the pockets (depressions) 20 is preferably no more than 3 mm

[0048] In use a sensor attached to an elevator car can detect these pockets 20 and measure the number of pockets 20 which the sensor passes in a measured period of time. The method of detection will vary depending on the sensor used, but may for example be based on a detected magnetic field strength, a strength of reflected electromagnetic radiation, the presence/absence of electromagnetic radiation and/or the strength or time of flight of a reflected ultrasound pulse. Since, in this example, the adjacent pockets 20 are spaced equally apart, these measurements can be straightforwardly used to calculate the speed of the elevator car relative to the guide rail 1. The pocket width 24 is first added to the separation distance 22, and this total distance is then multiplied by the number of pockets passed, as measured by the sensor. Alternatively, this total distance may be determined through edge detection (of rising edges or falling edges) in a sensor signal. This value is then divided by the time period during which the sensor was measuring, thereby giving the speed of the elevator car relative to the guide rail 1. In some elevator systems it may be possible for this calculation to be carried out by the sensor, while in other systems the information detected by the sensor may be sent to a control system which will then process the information from the sensor to determine the speed of the elevator car. The pockets 20 could also be used to determine the position of the elevator car relative to the guide rail 1. For example, a sensor could detect a particular pocket 20 as being a start pocket and could then keep a simple count of the number of pockets which the sensor detects, for a particular period of travel in a single direction, and could then translate this pocket count into a distance value representing the position of the elevator within the hoistway relative to the start pocket. In a typical example, the start pocket may be at the top or bottom of the pattern, representing the extremes of the elevator's possible movement, but in principle any reference pocket may be used. Alternatively the separation 22 between the pockets 20 and/or the width 24 of the pockets could be varied along the length of the pattern sufficiently that these differences are detectable by the sensor. These variations could have a repeating pattern. However, the pocket dimensions could alternatively be varied in a non-repeating way so that from a particular sensor reading (or set of sensor readings) the sensor, or the control, could determine from a reference copy of the pattern stored in a memory the absolute position of the elevator car. Such position measurements may of course also be used to determine the speed of the elevator car.

[0049] FIG. 3 schematically shows a possible method of manufacture of the guide rail 1 shown in FIGS. 2a and 2b. In this method the guide rail 1 is rolled between a first roller wheel 30 and a second roller wheel 32. The arrow 34 shows the direction of the motion of the guide rail 1 as the guide rail is being rolled between the wheels 30 and 32. The first roller wheel 30 is moving, from the perspective shown in FIG. 3, in an anticlockwise direction, as shown by the directional arrow 36. The second roller wheel 32 is moving in the clockwise direction, as shown by the arrow 38. The second roller wheel 32 comprises a number of raised portions 31. As the guide rail 1 is rolled between the two wheels 30, 32, the second roller wheel 32 creates depressions in the surface of the guide rail 1, i.e. it forms the pockets 20. Therefore, the size of each of these raised portions 31 determines the size of each of the pockets 20 of the guide rail 1. The separation distance between the two roller wheels 30, 32 determines the depth of each of the pockets 20. The depth of the pockets 20 in some examples will be less than half of the overall thickness of the guide rail section 4, and could be less than a quarter of the overall thickness of the guide rail section 4.

[0050] FIG. 4 shows a portion of an alternative guide rail 41 which is another example of the present disclosure. The pattern region 46 of the guide rail 41 of FIG. 4 comprises a number of marker regions 40 which are areas of the surface of the guide rail 41 which have been ground or given a mirror finish so that they have a different surface roughness from the guide rail material. These marker regions 40 could be easily detected using a diffuse-reflective sensor, although other sensors could also be suitable.

[0051] FIG. 5 shows a portion of another alternative guide rail 51 which is another example of the present disclosure. The guide rail 51 of FIG. 5 has a pattern region 56 comprising a plurality of drilled holes 50 spaced along substantially the whole length of the guide rail. In some examples the holes could be drilled all the way through the guide rail (through holes) with the advantage that this forms the same pattern simultaneously on both sides of the guide rail 1, or they could preferably be drilled (or otherwise machined) only part of the way through the thickness of the guide rail section. These kinds of holes are known as blind holes. Blind holes have the advantage of removing less material from the guide rail 1 and therefore having less of an impact on the strength of the guide rail 1. With through holes, a beam sensor may be used to detect the holes by placing a beam transmitter on one side of the rail and a beam receiver on the other side of the rail such that the transmitted beam is broken except when a hole passes between transmitter and receiver.

[0052] FIG. 6 shows a portion of another alternative guide rail 61 which is another example of the present disclosure. The guide rail 61 has a pattern region 66. The pattern region 66 comprises an optical, machine-readable representation of data, for example a barcode or preferably a two dimensional matrix code. The code 66 could be printed or laser etched directly onto the guide rail 61.

[0053] The code 66 can be detected by a sensor, and, in use, the sensor could determine the position of an elevator car relative to the guide rail 61 by referencing the part of the code 66 detected by the sensor at a given time to a copy of the code stored in a memory of the elevator system. This position information could then be used by the elevator system to determine the speed of the elevator car relative to the guide rail 61. Alternatively, the code 66 could contain some repeating pattern, present at certain pre-defined intervals, which could then be detected by the sensor and used to calculate the speed and position of the elevator car relative to the guide rail similarly to the methods described above. This code 66 could be easily detected using an optical sensor, although other sensors would be suitable.

[0054] FIG. 7 shows a portion of another alternative guide rail 71. The pattern portion 76 of this guide rail comprises a plurality of coloured regions 70. Adjacent regions 70 could be coloured with the same colour (with a different colour in between such as the natural colour of the guide rail) or could be coloured with different colours. Optionally these colours could form a non-repeating pattern along the length of the guide rail. This non-repeating pattern could be used to detect the position of an elevator car relative to the guide rail 71 as discussed above. The coloured regions 70 could be used in combination with the other marker regions disclosed herein, or colour could be applied within any of the other regions disclosed herein. These coloured regions 70 could be most easily detected using an optical sensor, although other sensors would be suitable.

[0055] FIG. 8 shows a guide rail 81 positioned in use within an elevator system 80. The elevator system includes a car 82, within which there is located a sensor 84. The guide rail 81 could be any of the examples of this disclosure which are disclosed herein. As the elevator car 82 moves up and down the hoistway, along the guide rail 81, the sensor 84 detects the pattern which is present on a surface of the guide rail 81 and can thereby determine certain measurements of the motion of the elevator, for example the speed or position of the elevator car 82 relative to the guide rail 81. It will be appreciated that FIG. 8 is somewhat illustrative and the dimensions of the pattern have been greatly exaggerated in relation to the car 82 for the sake of illustration.

[0056] The sensor could be an optical sensor, which would be particularly well-suited to detecting coloured marker regions and bar codes or matrix codes. The sensor could be a diffuse-reflective sensor, which would be particularly suitable for detecting areas of the guide rail having different surface roughness or a mirror finish. The sensor could be an infrared sensor. The sensor could be a beam sensor. The sensor 84 could be an ultrasound sensor or the sensor 84 could be an inductive sensor. Inductive and ultrasound sensors provide the added benefit compared to an optical sensor that they are not affected by light conditions within the hoistway.

[0057] It will be appreciated by those skilled in the art that the invention has been illustrated by describing one or more specific embodiments thereof, but is not limited to these embodiments; many variations and modifications are possible, within the scope of the accompanying claims.