FI124119B

FI124119B - Lift arrangement for calculating control data for a lift

Info

Publication number: FI124119B
Application number: FI20126337A
Authority: FI
Inventors: Ari Kattainen; Lauri Stolt
Original assignee: Kone Corp
Priority date: 2012-12-19
Filing date: 2012-12-19
Publication date: 2014-03-31
Also published as: ES2775011T3; FI20126337A; EP2746207A1; EP3275823B1; EP3275823A1; EP2746207B1

Description

ELEVATOR ARRANGEMENT OF COMPUTING CONTROL INFORMATION FOR ELEVATOR

TECHNICAL FIELD

5 The present invention relates generally to elevators and measuring masses or forces that affect the operation of the elevators.

BACKGROUND OF THE INVENTION

10 A typical elevator includes an elevator car, a hoisting machine for moving the elevator car, at least one counter weight, and traction means such as a rope, cable, chain, or belt. Those traction means connects the elevator car and the at least one counter 15 weight to each other. The traction means pass through a traction sheave which is connected to the hoisting machine, for example, to a drive shaft of the hoisting machine. The counter weight is also termed a compensating weight. A person skilled in the art knows that 20 the typical elevator includes more components but the above-mentioned components are the most relevant from a point of view of the invention.

It is known to measure a load in an elevator car, i.e. the mass of human being (s) and/or mass of 25 object(s). The load can be measured at the point where

the elevator car is attached to the traction means. A

δ sensor, such as a load sensor, can be arranged to that c\j ± point to measure the load. Then the sensor in fact o 1 measures how much the elevator car and the load weigh o ^ 30 together. Alternatively, the sensor can be arranged in

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£ the floor of the elevator car. Then the sensor r-v. measures only the load of the elevator car.

co g In addition to the elevator car, the load,

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£ and the counter weight, a fourth mass affects the op- ^ 35 eration of the elevator. The fourth mass is the mass of the traction means. If the elevator car is located 2 at the bottom part of the hoistway, the major portion of the traction means is located on the same side as the elevator car. In more detail, the major portion of the traction means is located on the same side of the 5 traction sheave as the elevator car. Correspondingly, if the elevator car is located at the top part of the hoistway (as in FIG. 8B) , the major portion of the traction means is located on the same side as the counter weight.

10 It is possible to compensate the mass of the traction means by using support means. For example, a cable connecting the bottom of the elevator car to the bottom of the counter weight operates as the support means. Especially the support means having the same 15 mass balance mechanically the masses on the opposite sides of the traction sheave.

US 7,784,589 describes an assembly for measuring a load in a lift cage, wherein the lift cage can be considered to correspond to the elevator car and a 20 drive engine (a term used in US 7,784,589) can be considered to correspond to the hoisting machine. This assembly includes a small-area load sensor that measures vibration. The small-area load sensor is, for example, 0.2 mm thick, and it can be placed between a 25 support and a first damping body of the drive engine to measure vibration caused by the drive engine. The vibration increases when the load has increased in the ^ lift cage and the drive engine moves the lift cage. An ^ electronic evaluating system using the small-area load o 30 sensor is calibrated so that the system is first cali- ^ brated to zero when the lift cage is empty. Then the system is calibrated to a standardized output voltage,

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e.g. 10 volts, when there is the maximum load in the £3 lift cage. As described US 7,784,589, a single sensor co CVJ 35 can be placed in the machine bed to measure the total ° weight of the elevator car, the load, and a certain portion of the traction means.

3

As generally known, a hoisting machine of an elevator includes a brake which affects the traction sheave connected to the hoisting machine. When the brake is on, the hoisting machine is not in action and 5 the elevator car does not move. Correspondingly, when the brake is off, the hoisting machine is running and is able to move the elevator car up or down.

A load in the elevator car and other masses naturally affect torques on the traction sheave. The 10 elevator car causes either a clockwise torque or an anticlockwise torque on the traction sheave. Correspondingly, the counter weight causes an opposite torque compared to the torque caused by the elevator car. The sum of the clockwise torque and the anti-15 clockwise torque is termed in this specification "torque on the traction sheave".

When the brake is on, the torque reaches its maximum value, if the elevator car has the maximum load and it is located at the bottom part of the 20 hoistway because then the mass of the traction means has its greatest possible effect to the torque on the traction sheave. Usually the counter weight has a mass that is as great as a sum of the mass of the elevator car and half of the maximum load. Then the torque on 25 the traction sheave reaches its minimum value when the elevator car has half of the maximum load. It is known to form a mathematical formula to estimate the effect ^ of the traction means to the torque on the traction o ^ sheave, but masses are only one factor that affects 0 30 the torque. In addition to the masses of the elevator ^ car, a load of the elevator car, the counter weight 1 and the traction means, static friction affects the

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torque. Furthermore, the tension of support means also N- £3 affect the torque on the traction sheave, if the sup-

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cvj 35 port means are used to connect the elevator car to the counter weight.

4

When the brake is to be released the hoisting machine should at first provide a torque that has the same magnitude than the torque on the traction sheave but in the opposite direction, to keep the elevator 5 car at its current position in the hoistway. When the hoisting machine aims to move the elevator car the torque provided by the hoisting machine should be changed to move the elevator car either up or down. In addition to the above-mentioned masses, acceleration 10 resulted by the hoisting machine and kinetic friction affect the torque on the traction sheave. When using the support means the tension of the support means also affect the torque.

Measuring the mass of the elevator car, or 15 measuring the mass of its load, do not necessarily provide such measuring data that it would be possible to determine accurate enough the forces on the both sides of the traction sheave.

20 SUMMARY OF THE INVENTION

Due to certain safety instructions the load measuring must be performed when the brake of the hoisting machine is on. The invention aims to measure, in an accurate manner, the forces that have effect on 25 the traction sheave when the brake is on or off. These measuring results are suitable for controlling the break and the hoisting machine. For example, when the δ torque is calculated in the accurate manner, the

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^ hoisting machine can be used with an exactly appropri- o 1 30 ate power. Then the hoisting machine moves the eleva- ^ tor car very smoothly up or down. Thus, one advance of £ the invention is that it may enhance user experience |s^ of the people using the elevator because the elevator co g car moves very smoothly. This feature is also termed ^ 35 "ride comfort", o

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5

As mentioned in the above, the elevator car causes either clockwise torque or anticlockwise torque on the traction sheave, and the counter weight causes the opposite torque. Therefore, forces are measured on 5 the both sides of the traction sheave of the hoisting machine by utilizing, not only one sensor, but at least two sensors. In more detail, a first sensor is arranged to measure magnitude of a first force on one side of the traction sheave and a second sensor is ar-10 ranged to measure magnitude of a second force on the other side of the traction sheave. Then, in one embodiment of the invention, the torque on the traction sheave can be determined from a difference between the measuring result of the first sensor and the measuring 15 result of the second sensor.

In addition the difference between the first and the second force, also a sum of the first and the second force can be computed. The difference and the sum are examples of items of control information which 20 are usable in the controlling of the elevator. The difference and/or sum can also be used to calculate other items of control information, such as a mass of a load in the elevator car.

The invention comprises an arrangement for an 25 elevator, the elevator comprising at least an elevator car, a hoisting machine for moving the elevator car, at least one counter weight, and traction means that ^ connect the elevator car and the at least one counter o ^ weight to each other, wherein the traction means pass o 30 through a traction sheave connected to the hoisting ° machine, and wherein £ a first mass includes at least the mass of the elevator car and a second mass includes at least co g the mass of the at least one counter weight, the ar- 35 rangement comprising c\j 6 a first sensor for providing a first measuring result, the first measuring result representing magnitude of a first force which is affected by at least the first mass, characterized in that the ar-5 rangement further comprises a second sensor for providing a second measuring result, the second measuring result representing magnitude of a second force which aims to rotate the traction sheave to an opposite direction than the 10 first force; and a computing unit for computing, on the basis of the first measuring result and the second measuring result, at least one of the following: a difference between the first measuring 15 result and the second measuring result, - a difference between the first force and the second force, - a sum of the first measuring result and the second measuring result, 20 - a sum of the first force and the second force .

An advance of the invention is that, due to the two sensors, the difference between the measuring results is an accurate piece of measuring information.

25 For example, rope tensions related to the elevator car do not deteriorate this piece of measuring information ? and, if needed, the rope tensions can be calculated.

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Another advance of the invention is that the o ' forces on the both sides of the traction sheave can be o 00 30 calculated. Thus, there is less need to estimate those

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£ forces. For example, kinetic friction and its possible (abnormal) change can be detected, co

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In one embodiment of the arrangement the δ hoisting machine is mounted on a first part of a ma- c\j 35 chine bed and the first measuring result and the se- 7 cond measuring result disclose a position of the first part in relation to a second part of the machine bed.

In one embodiment of the arrangement the first sensor and the second sensor are located between 5 the first part and the second part of the machine bed.

In one embodiment of the arrangement the first sensor is located between the traction sheave and the elevator car and the second sensor is located between the traction sheave and the at least one coun-10 ter weight.

In one embodiment of the arrangement the elevator car and the at least one counter weight are further connected to each other by support means.

In one embodiment of the arrangement the 15 first sensor is located between the traction means and the elevator car and the second sensor is located between the support means and the elevator car.

In one embodiment of the arrangement the first sensor is located between the traction means and 20 a roof of the elevator car and the second sensor is located between the traction means and a bottom of the elevator car.

In one embodiment of the arrangement the first force is further affected by at least one of the 25 following: static friction, kinetic friction, acceler- >- ation of the first mass, o ^ In one embodiment of the arrangement the seep cond force is affected by at least one of the follow- ° ing: the second mass, static friction, kinetic fric- ^ 30 tion, acceleration of the second mass, a device for

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providing rope tension.

£3 In one embodiment of the arrangement the

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cvj first sensor and the second sensor are configured to ^ measure one of the following quantities: load, pres- 35 sure, distance, resistance.

8

In one embodiment of the arrangement the traction means comprise at least one of the following means: a rope, cable, chain, or belt.

The invention comprises a method of computing 5 control information for an elevator, the elevator comprising at least an elevator car, a hoisting machine for moving the elevator car, at least one counter weight, and traction means that connect the elevator car and the at least one counter weight to each other, 10 wherein the traction means pass through a traction sheave connected to the hoisting machine, and wherein a first mass includes at least the mass of the elevator car and a second mass includes at least the mass of the at least one counter weight, method 15 comprising obtaining from a first sensor a first measuring result representing magnitude of a first force which is affected by at least the first mass; characterized in that the method further comprises 20 obtaining from a second sensor a second meas uring result representing magnitude of a second force which aims to rotate the traction sheave to an opposite direction than the first force; and computing, on the basis of the first measur-25 ing result and the second measuring result, at least one of the following: a difference between the first measuring ? result and the second measuring result, o ^ - a difference between the first force and o 30 the second force, ° - a sum of the first measuring result and the second measuring result, Q.

- a sum of the first force and the second £3 force

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c\j 35 In one embodiment of the method the hoisting ° machine is mounted on a first part of a machine bed and the first measuring result and the second measur- 9 ing result disclose a position of the first part in relation to a second part of the machine bed.

In one embodiment of the method the first sensor and the second sensor are located between the 5 first part and the second part of the machine bed.

In one embodiment of the method the first sensor is located between the traction sheave and the elevator car and the second sensor is located between the traction sheave and the at least one counter 10 weight.

In one embodiment of the method the elevator car and the at least one counter weight are further connected to each other by support means.

In one embodiment of the method the first 15 sensor is located between the traction means and the elevator car and the second sensor is located between the support means and the elevator car.

In one embodiment of the method the first sensor is located between the traction means and a 20 roof of the elevator car and the second sensor is located between the traction means and a bottom of the elevator car.

In one embodiment of the method the first force is further affected by at least one of the fol- 25 lowing: static friction, kinetic friction, accelera- ? tion of the first mass, o ^ In one embodiment of the method the second o force is affected by at least one of the following: ° the second mass, static friction, kinetic friction, 30 acceleration of the second mass, a device for provid- Q.

ing rope tension.

Γ"» £3 In one embodiment of the method one of the

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c\j following quantities is measured with the first sensor ° and the second sensor: load, pressure, distance, re- 35 sistance.

10

In one embodiment of the method the traction means comprise at least one of the following means: a rope, cable, chain, or belt.

In one embodiment, the method comprises cal-5 culating, on the basis of the difference, a mass of a load in the elevator car.

In one embodiment, the method comprises calculating, on the basis of the difference, calculating, on the basis of the difference, torque on the traction 10 sheave.

In one embodiment, the method comprises calculating, on the basis of the sum, load on bearings of the traction sheave.

In one embodiment, the method comprises cal-15 culating, on the basis of the sum, at least one of the following tensions: a tension of the traction means, a tension of support means, wherein the elevator car and the at least one counter weight are connected to each other by the support means.

20

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constitute a part of this specification and include certain exemplary embodiments of the invention.

25 FIGURE 1A illustrates a machine bed and an empty elevator car.

. FIGURE IB illustrates the machine bed and the δ elevator car with a load.

c\j ^ FIGURE 2A illustrates an empty elevator car o ^ 30 in an elevator that comprises support means.

^ FIGURE 2B illustrates the elevator car with a x £ load in the elevator that comprises the support means.

FIGURE 3A illustrates masses and forces when co 2 an elevator car is empty.

c\j T- 35 FIGURE 3B illustrates masses and forces when o ^ the elevator car carries a load.

11 FIGURE 4A illustrates torques when an elevator car is empty.

FIGURE 4B illustrates torques when the elevator car carries a load.

5 FIGURE 5 shows an elevator arrangement.

FIGURE 6 shows a method of computing control information for an elevator.

FIGURE 7A shows a hoisting machine located on the floor of a hoistway.

10 FIGURE 7B shows a hoisting machine located on a wall of a hoistway.

FIGURE 7C shows a flat hoisting machine and an appropriate machine bed for it.

FIGURE 8A shows a hoisting machine located on 15 a top of a hoistway.

FIGURE 8B shows an arrangement comprising traction means and support means.

DETAILED DESCRIPTON OF THE INVENTION 20 It is appreciated that the following embodi ments are exemplary. Although the specification may refer to "one" or "some" embodiment (s), the reference is not necessarily made to the same embodiment (s) , or the feature in question may apply to multiple embodi-25 ments. Single features of different embodiments may be combined to provide further embodiments.

FIGURE 1A illustrates an empty elevator car 6 ? and a machine bed. The machine bed comprises a first o ^ part 3a and a second part 3b which are connected to o 30 each other, for example, with bolts and nuts through machine bed springs 4a and 4b (the bolts and nuts are x not shown) . A hoisting machine 2 is attached to the

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first part 3a of the machine bed. The hoisting machine g 2 maY include the first part 3a, or alternatively, the c? 35 first part 3a may be a separate part. The hoisting ma- ° chine 2 comprises a drive shaft 1 to which a traction sheave 9 is attached. Traction means 8 comprises, for 12 example, a hoisting rope that passes through the traction sheave 9 and connects the elevator car 6 to a counter weight 7. The counter weight 7 is heavier than the elevator car 6 when the elevator car is empty.

5 Thus, the machine bed spring 4a has compressed and the machine bed spring 4b has stretched. The position of the first part 3a (of the machine bed) has changed in relation to the second part 3b so that the first part 3a is tilted to the left. The illustration shown in 10 FIG. 1A as well as other illustrations in FIG. IB, 2A, and 2B are simplified and exaggerated. The elevator car 6 and the counter weight 7 are in practice much larger than the hoisting machine 2 and the traction means 8 are in practice longer.

15 FIGURE IB illustrates the same machine bed and the elevator car 6 with a load. The elevator car 6 and the load are together heavier than the counter weight 7 and thus the machine bed spring 4b has constricted and the machine bed spring 4a has stretched. 20 In addition, the position of the first part 3a is changed in relation to the second part 3b. In other words, the first part 3a is tilted to the right.

FIGURE 2A illustrates an empty elevator car 6 in an elevator that comprises support means 10. Also 25 this elevator comprises a hoisting machine 2 with a machine bed, but those components are omitted from the figure. The support means 10 connect the elevator car ^ 6 via the diverting pulleys 11 to the counter weight o 7. A first spring 4a connects the traction means 8 to 0 30 the elevator car 6 and a second spring 4b connects the ^ support means 10 to the elevator car 6. One benefit of 1 the support means 10 is that they solve the known Q.

loose rope problem. FIG. 2A illustrates in which man-£3 ner the springs 4a and 4b stretch. When the elevator

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cu 35 car 6 is empty the second spring 4b is slightly more ° stretched than the first spring 4a.

13

When comparing the springs 4a and 4b in FIG. 2A to the machine bed springs 4a and 4b in FIG. 1A certain similarities can be detected between the lengths of the springs. For example, the spring 4b in 5 FIG. 2A has stretched approximately as much as the spring 4b in FIG 1A.

FIGURE 2B illustrates the elevator car 6 with a load (in the elevator comprising the support means 10 10). Due to the load the first spring 4a has stretched more and the second spring 4b has constricted. When comparing the springs 4a and 4b to the machine bed springs 4a and 4b in FIG. IB certain similarities can be again detected. For example, the spring 4b in FIG.

15 2B has constricted approximately as much as the spring 4b in FIG IB.

Figures 2A and 2B includes an assumption that the support means 10 are not tightened and thus the mass of the elevator car 6 (with a load or not) and 20 the mass of the counter weight affect the spring 4b and the measuring result of the second sensor 5b. In fact, the support means 10 must be tightened for safety reasons. When the support means 10 are tightened the spring 4b stretches and also the spring 4a 25 stretches. Because the support means 10 are tightened, the first sensor 5a and the second sensor 5b provide in FIG. 2B greater measuring values than in FIG. 2A. ? Nevertheless, the difference between the measuring re- ^ suit of the first sensor 5a and the measuring result o 30 of the second sensor 5b are usable in the invention.

^ For example, the mass of the load in the elevator car 6 can be determined on basis of the difference between Q.

the measuring results.

I"'' £3 FIGURE 3A illustrates masses and forces when co cvj 35 an elevator car is empty. A first mass Mi comprises at ^ least the mass of the elevator car, such as the mass of the elevator car 6 shown in FIG. 1A or 2A. A second 14 mass M2 comprises at least the mass of the counter weight, such as the mass of the counter weight 7 shown in FIG. 1A or 2A. When the brake is on, the traction sheave 9 does not rotate and forces Fi and F2 can be 5 considered as gravity forces that affect the masses Mi and M2. When the brake is released, the hoisting machine rotates the traction sheave 9 and moves the elevator car. Then, in addition to gravity, the acceleration caused by the hoisting machine affects the forces 10 Fi and F2.

FIGURE 3B illustrates masses and forces when the elevator car has a load. The load is, for example, a human being as shown in FIG. IB or 2B. The second mass M2 and the second force F2 are the same as in FIG. 15 3A because nothing has changed on that side of the traction sheave 9 (assuming that the brake is on in FIG. 3A and 3B) . On the other side of the traction sheave 9 the first mass Mi has increased because the load has increased. Thus, the force Fi is greater in 20 FIG. 3B than in FIG. 3A.

In figures 3A and 3B counterforces of the forces Fi and F2 are omitted. If the elevator car does not move, the force affecting the elevator car and the counterforce are as great and thus their net force (F) 25 is zero. Newton's second law states that the net force (F) acting upon an object is equal to the rate at which its momentum changes with time. If the mass (m) ^ of the object is constant, this law implies that the 0 ^ acceleration (a) of an object is directly proportional 0 30 to the net force acting on the object. The same sub- ° ject matter can be expressed as a formula: F = m · a.

When the elevator car moves, the force affecting the

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elevator car differs from the counterforce and then £3 their net force (F) is also differs from zero.

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cvj 35 FIGURE 4A illustrates torques on the traction ° sheave 9 when the elevator car is empty. The first mass Mi (or the first force Fi) shown in 3A causes a 15 first torque Τι and correspondingly, the second mass M2 (or the second force F2) shown in 3A causes a second torque T2. The torques Ti and T2 have opposite directions. The force F2 (in FIG 3A) is greater than the 5 force Fi and thus also the torque T2 is greater than the torque Ti.

The torque on the traction sheave 9 is marked with Ts. The torque Ts is the sum of the first torque Ti and the second torque T2.

10 FIGURE 4B illustrates torques when the eleva tor car is loaded. The first mass Mi (or the first force Fi) shown in FIG. 3B causes a first torque Ti and the second mass M2 (or the second force F2) shown in FIG. 3B causes a second torque T2. Torque Ts is the sum 15 of the first torque Ti and the second torque T2. Be cause of the load, the first mass Mi and the first force Fi have increased so much that the torque Ts has the opposite direction compared to the torque Ts shown in FIG. 4A.

20 FIGURE 5 relates to some elevator arrangement comprising at least an elevator car 6, a hoisting machine 2, at least one counter weight 7, and traction means 8. The traction means 8 connect the elevator car 6 and the at least one counter weight 7 to each other 25 and the traction means pass through a traction sheave 9 connected to the hoisting machine 2. Masses affect the traction sheave 9 so that a first mass Mx includes ? at least the mass of the elevator car 6 and a second o mass M2 includes at least the mass of the at least one o 30 counter weight 7. The elevator arrangement comprises a ° first sensor 5a and a second sensor 5b, wherein the jc first sensor 5a provides a first measuring result and

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the second sensor 5b provides a second measuring re-£3 suit. The first measuring result represents magnitude w 35 of a first force Fx which is affected by at least the ° first mass Mi. The second measuring result represents magnitude of a second force F2 which aims to rotate 16 the traction sheave 9 to an opposite direction than the first force Fi. The elevator arrangement further comprises a computing unit 12 to compute, on the basis of the first measuring result and the second measuring 5 result, a difference between the first mass Mi and the second mass M2.

The first sensor 5a and the second sensor 5b comprise wiring 51 through which the computing unit 12 is able to obtain the first measuring result and the 10 second measuring result. In one embodiment the computing unit 12 comprises a processor and a memory for storing at least program code. In one embodiment the wiring 51 is omitted, i.e. the measuring results are transmitted wirelessly to the computing unit 12.

15 FIG. 1A and IB shows such embodiment for the arrangement of FIG. 5 wherein the first sensor 5a and the second sensor 5b are located in the machine bed of the hoisting machine 2. In more detail, the sensors 5a and 5b are arranged between the first part 3a and the 20 second part 3b of the machine bed. The sensors 5a and 5b disclose a position of the first part 3a in relation to the second part 3b of the machine bed. The first part is, for example, slightly tilted or twisted in relation to the second part.

25 FIG. 2A and 2B shows another embodiment for the arrangement of FIG. 5. In this embodiment the first sensor 5a is located between the traction means ? 8 and the elevator car 6 and the second sensor 5b is o ^ located between the support means 10 and the elevator 0 30 car 6.

° It is reasonable that the first sensor 5a and 1 the second sensor 5b measure the same quantity though Q.

they could measure different quantities. The sensors 5a and 5b measure, for example, one of the following 35 quantities: load, pressure, distance, resistance. The ° sensors 5a and 5b disclose the quantity, for example, in millivolts from 0 mV to 10 mV. In one embodiment of 17 the arrangement at least other of the first sensor 5a and the second sensor 5b is calibrated to provide a zero value (e.g. 0 mV) as its measurement result when the mass Mi reaches its minimum value. This happens 5 when elevator car is empty and is located at the top part of the hoistway. A person skilled in the art knows that the calibration of the sensors 5a and 5b can be performed in various manners.

A difference between the first measuring re-10 suit (provided by the first sensor 5a) and the second measuring result (provided by the second sensor 5b) is, for example, 6.7 mV - 4.4 mV = 2.3 mV.

In one embodiment the difference between the first force Fi and the second force F2 is calculated 15 from the difference between the first measuring result and the second measuring result. For example, if this difference (marked with Ad) is 2.3 mV, the numeric value 2.3 can be input in a formula which results in the difference (marked AD) between the first force Fi 20 and the second force F2 . The formula is, for example, AD = Ad · 100 N. Thus, the Ad value 2.3 would result in 230 N.

As mentioned in the background of the invention, measuring the mass of the elevator car 6, or 25 measuring the mass of its load, do not necessarily provide such measuring data that it would be possible to accurately determine the forces on the both sides ^ of the traction sheave, o ^ When the elevator car stays in its location, o 30 in addition to the first mass Mi, the first force Fi is ^ affected by static friction and the first measuring result (provided by the first sensor 5a) includes the

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static friction. Correspondingly, the second force F2 r-- ” is affected by static friction and the second measur- co c\j 35 ing result (provided by the second sensor 5a) includes ^ the static friction.

18

When the elevator car moves, in addition to the first mass Mi, the first force Fi is affected by kinetic friction and the first measuring result includes the kinetic friction. Correspondingly, the se-5 cond force F2 is affected by kinetic friction and the second measuring result includes the kinetic friction. In addition, the first force Fi is affected by acceleration of the first mass Mi and the second force F2 is affected by acceleration of the second mass M2.

10 The elevator arrangement shown in FIG. 5 pro vides measuring results about the forces Fi and F2 shown in FIG. 3A and 3B. These measuring results can be utilized when computing control information for the elevator.

15 FIGURE 6 shows a method of computing the con trol information for an elevator. The method comprises the steps of: obtaining 601 from a first sensor 5a a first measuring result representing magnitude of a first 20 force Fi which is affected by at least the first mass

Mi ; obtaining 602 from a second sensor 5b a second measuring result representing magnitude of a second force F2 which aims to rotate the traction sheave 25 9 to an opposite direction than the first force Fi; and computing 603, on the basis of the first ? measuring result and the second measuring result, at ^ least one of the following items of control the infor- o 30 mation: a difference between the first force Fi and ° the second force F2, or a sum of the first force Fi and ^ the second force F2.

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As described in the above, the elevator ar- £3 rangement shown in FIG. 5 comprises various embodi- co c\j 35 ments. Also those embodiments are usable in the method ^ and can be combined with it.

19

The difference between the first force Fi and the second force F2 is an example of an item of the control information and the sum of the first force Fi and the second force F2 is other example of an item of 5 the control information.

The elevator can be controlled with one or more items of the control information, for example, to enhance the ride comfort. The following pseudo code illustrates in which manner the power of the hoisting 10 machine of the elevator is controlled by the difference of the first force Fi and the second force F2. In this pseudo code the difference is stored in a variable termed "diff" and a variable termed "torque" is set such value of the torque that the hoisting machine 15 should provide when the brake is released:

IF 0 < diff < 1 THEN torque = 15 Nm ELSE

IF 1 < diff < 2 THEN torque = 45 Nm ELSE

IF 2 < diff < 3 THEN torque = 69 Nm ELSE

20 IF 8 ^ diff < 9 THEN torque = 165 Nm ELSE

IF 9 < diff < 10 THEN torque = 189 Nm The difference and/or sum can be used in the calculation of other items of control information, such as: 25 - a mass of a load in the elevator car 6 the torque (Ts) on the traction sheave 9 a load on bearings of the traction sheave 9 ? - a tension of the traction means 8 o ^ - a tension of the support means 10.

o 30 For example, the mass Am of the load in the ° elevator car 6 can be calculated by using a formula:

Am = Ad · 35 kg. For example, a Ad value 2.3

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representing the difference would result in 80.5 kg.

Is» £3 In one embodiment the method comprises calcu- co C\J 35 lating, on the basis of the sum, load on bearings of ° the traction sheave 9. The bearings connect the trac tion sheave 9 to hoisting machine 2.

20

In one embodiment the method comprises calculating, on the basis of the sum, at least one of the following tensions: a) a tension of the traction means 8 or b) a tension of support means 10 assuming that 5 the elevator car (6) and the at least one counter weight 7 are connected to each other by the support means 10. The following pseudo code illustrates in which manner the sum of the first measuring result, 6.7 mV (provided by the first sensor 5a), and the se-10 cond measuring result 4.4 mV (provided by the second sensor 5b) is used in the calculation of the tension of the traction means 8. In this example the sum of the measuring results is: 6.7 mV + 4.4 mV = 11.1 mV.

15 According to the pseudo code the tension is 1150 N when the numeric value of the sum is 11.1:

IF 9 < sum < 10 THEN tension = 950 N ELSE IF 10 < sum < 11 THEN tension = 1050 N ELSE IF 11 < sum < 12 THEN tension = 1150 N ELSE

20

Instead of a pseudo code, an appropriate formula could also be used to calculate the sum.

A rope tension related to the traction means 8 (or support means 10) may increase because of an ab-25 normal change in kinetic friction. This change can be detected, if the sum is calculated repeatedly when the elevator moves. Then the elevator car can be stopped ? for safety reasons, o ^ The following three figures illustrate dif- o 30 ferent embodiments for hoisting machines.

FIGURE 7A shows a hoisting machine 2 located χ on the floor 3b of a hoistway. Therefore the traction

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means 8 pass upwards from the hoisting machine 2. By £3 using diverting pulleys the elevator car can be moved 35 up and down though the hoisting machine is located on ° the floor of the hoistway. The first part 3a of the machine bed of the hoisting machine 2 is made of 21 steel. The floor of the hoistway, which is made of reinforced concrete, operates as the second part 3b of the hoisting machine. Special bolts extend deep in the reinforced concrete. The first part 3a of the machine 5 bed includes holes so that the bolts penetrate the holes and the nuts can be screwed into the bolts. A dashed line 71 separates the hoisting machine 2 and the traction sheave 9 into two sides. As in the above, forces are measured on the both sides of the traction 10 sheave 9. A first sensor 5a and a second sensor 5b are located as far from the dashed line 71 because then the sensors (5a, 5b) probably provide the most relia ble measurement results.

FIGURE 7B shows a hoisting machine located on 15 a wall of a hoistway. Also in this embodiment a second part 3a of the machine bed is made of concrete and a dashed line 71 separates the hoisting machine 2 and its traction sheave 9 into two sides. A first portion 81 of the traction means 8 meets the traction sheave 9 20 in a different angle than a second portion 82 of the traction means 8. In more detail, the second portion 82 of the traction means 8 is parallel to the dashed line 71 but the angle between the first portion 81 of the traction means 8 and the dashed line 71 is about 25 45 degrees. At least one diverting pulley 72 or 73 can be used to make the traction means 8 to meet the traction sheave 9 in a certain angle. A person skilled in ί the art knows that the traction sheave 9 must provide ^ enough touching surface for the traction means 8.

o 30 FIGURE 7C shows a flat hoisting machine 2 and ^ an appropriate machine bed for it. The hoisting ma- chine 2 is placed on the floor of a hoistway so that Q.

the drive shaft 1 of the hoisting machine 2 is paralla £3 lei to the hoistway. The machine bed is made of two

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c\j 35 steel plates 3a, 3b which are twisted as shown m the ° figure. The steel plates function as a first part 3a and as a second part 3b of the machine bed. Four holes 22 74, 75, 76, 77 penetrate the parts 3a, 3b so that the first part 3a of the machine bed can be attached to the second part 3b by bolts and nuts. In accordance with the invention a first sensor 5a and a second sen-5 sor 5b should be placed between the parts 3a, 3b of the machine bed so that they are able to provide reliable measurement results about the torque on the traction sheave 9. Therefore, the sensors 5a, 5b are placed between the parts 3a, 3b close to holes 74 and 10 75. If the hoisting machine 2 rotates the traction sheave 9 to clockwise direction 78, the first part 3a pressures against the second part 3b at the first sensor 5a and simultaneously the first part 3a draws apart from the second part 3b at the second sensor 5b. 15 The sensors 5a and 5b measure this movement of the first part 3a.

The invention can be implemented in various manners. The following figures show two examples of implementing the invention.

20 FIGURE 8A shows a hoisting machine located on a top of a hoistway 83. Traction means 8 pass from the roof 61 of an elevator car 6 via the traction sheave 9 of the hoisting machine and via diverting pulleys 84, 85 to a counter weight (the counter weight not shown 25 in the figure). In one embodiment the first sensor 5a is located between the traction sheave 9 and the elevator car 6 and the second sensor 5b is located be- ? tween the traction sheave 9 and the at least one coun- o ^ ter weight (not shown in the figure). In FIGURE 8A the o 30 first sensor 5a is located between the traction means ° 8 and the elevator car 6 and the second sensor 5b is located at the diverting pulley 85. Alternatively, the

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second sensor 5b could be located at the bearings of £3 diverting pulley 84, or between the traction means 8

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cm 35 and the counter weight.

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23 FIGURE 8B shows an elevator arrangement comprising a hoisting machine which is located on the floor of a hoistway 86 and which uses a special type of traction means 8. The traction means 8 pass from 5 the roof of an elevator car 6 via diverting pulleys 89, 88 to the top of the counter weight 7 and from the bottom of the counter weight 7 via a diverting pulley 87 and via the traction sheave 9 to the bottom of the elevator car 6. Sensors 5a and 5b (for providing meas-10 urement results of the forces Fi and F2) are located as follows. The first sensor 5a is located between the traction means 8 and the roof of the elevator car 6 and the second sensor 5b is located between the traction means 8 and the bottom of the elevator car 6. A 15 device for providing rope tension is usually located in the bottom of the elevator car 6 as in this example. The device keeps the tension of the traction means 8 on an appropriate level, which is illustrated by the second force F2.

20 All or a portion of the exemplary embodiments described in the above can be implemented using known sensors, elevator components, a processor etc. One or more persons skilled in electronics and/or mechanics are able to advice preparation of the program code 25 that is needed in the implementation of the invention.

While the invention has been described in connection with a number of exemplary embodiments, and ? implementations, the invention is not limited to them, ^ but rather covers various modifications which fall 0 30 within the purview of prospective claims.

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Claims

1. Järjestely hissiä varten, joka hissi käsittää vähintään hissikorin (6), nostokoneen (2) hissiko-rin (6) liikuttamiseksi, vähintään yhden vastapainon 5 (7) , ja vetovälineet (8), jotka yhdistävät hissikorin (6) ja vähintään yhden vastapainon (7) toisiinsa, jossa vetovälineet (8) kulkevat nostokoneeseen (2) yhdistetyn vetopyörän (9) kautta, ja jossa ensimmäinen massa (Mi) sisältää vähintään hissi-10 korin (6) massan ja toinen massa (M2) sisältää vähintään vähintään yhden vastapainon (7) massan, joka järjestely käsittää ensimmäisen anturin (5a) ensimmäisen mittaustuloksen aikaansaamiseksi, joka ensimmäinen mittaustulos 15 edustaa ensimmäisen voiman (Fi) , johon vähintään ensimmäinen massa (Mi) vaikuttaa, suuruutta, tunnettu siitä, että järjestely käsittää edelleen toisen anturin (5b) toisen mittaustuloksen ai-20 kaansaamiseksi, joka toinen mittaustulos edustaa toisen voiman (F2) , joka pyrkii kiertämään vetopyörää (9) vastakkaiseen suuntaan kuin ensimmäinen voima (Fi) , suuruutta; ja laskentayksikön (12) vähintään yhden seuraavis- 25 ta laskemiseksi ensimmäisen mittaustuloksen ja toisen g mittaustuloksen perusteella: c\j τΐ - ensimmäisen mittaustuloksen ja toisen mitta- o ^ ustuloksen välinen erotus, CM - ensimmäisen voiman (Fx) ja toisen voiman (F2) £ 30 välinen erotus, £5 - ensimmäisen mittaustuloksen ja toisen mitta- S ustuloksen summa, C\1 o - ensimmäisen voiman (Fi) ja toisen voiman (F2) Cvl summa; jossa järjestely käsittää yhden seuraavista toteutuksista: (i) nostokone (2) on asennettu koneen rungon ensimmäiseen osaan (3a) ja ensimmäinen mittaustulos ja 5 toinen mittaustulos esittävät ensimmäisen osan (3a) aseman suhteessa koneen rungon toiseen osaan (3b); (ii) nostokone (2) on asennettu koneen rungon ensimmäiseen osaan (3a) ja ensimmäinen mittaustulos ja toinen mittaustulos esittävät ensimmäisen osan (3a) 10 aseman suhteessa koneen rungon toiseen osaan (3b) ja ensimmäinen anturi (5a) ja toinen anturi (5b) sijaitsevat koneen rungon ensimmäisen osan (3a) ja toisen osan (3b)välissä; (iii) hissikori (6) ja vähintään yksi vastapai-15 no (7) on yhdistetty edelleen toisiinsa tukivälineillä (10) ja että ensimmäinen anturi (5a) sijaitsee vetovä-lineiden (8) ja hissikorin (6) välissä ja toinen anturi (5b) sijaitsee tukivälineiden (10) ja hissikorin (6) välissä; tai 20 (iv) ensimmäinen anturi (5a) sijaitsee vetovä- lineiden (8) ja hissikorin (6) katon välissä ja toinen anturi (5b) sijaitsee vetovälineiden (8) ja hissikorin (6) pohjan välissä.An arrangement for an elevator, comprising an elevator car (6), a hoisting machine (2) for moving the elevator car (6), at least one counterweight 5 (7), and pulling means (8) connecting the elevator car (6) and at least one a counterweight (7) to each other, wherein the traction means (8) passes through a traction sheave (9) connected to the lifting machine (2) and wherein the first mass (Mi) contains at least the mass of the elevator car 10 (6) and the second mass (M2) a counterweight (7) having an arrangement comprising a first sensor (5a) for obtaining a first measurement result, the first measurement result 15 representing the magnitude of a first force (Fi) exerted by at least the first mass (Mi), characterized in that the arrangement further comprises a second sensor 5b) for obtaining a second measurement result ai-20, each second measurement representing a second force (F2) which tends to rotate the drive wheel (9) in the axial direction as the first force (Fi), greatness; and a calculating unit (12) for calculating at least one of the following from the first measurement and the second measurement g: c \ j τΐ - the difference between the first measurement and the second measurement result, CM - the first force (Fx) and the second force (F2). The difference between £ 30, £ 5 - the sum of the first measurement and the second measurement, C10 - the sum of the first force (Fi) and the second force (F2) Cv1; wherein the arrangement comprises one of the following embodiments: (i) the lifting machine (2) is mounted on the first part (3a) of the machine frame and the first measurement result and the second measurement result show the position of the first part (3a) relative to the second machine part (3b); (ii) the lifting machine (2) is mounted on the first part (3a) of the machine frame and the first measurement and the second measurement show the position of the first part (3a) 10 with respect to the second part (3b) of the machine body and the first sensor (5a) located between the first part (3a) and the second part (3b) of the machine frame; (iii) the elevator car (6) and at least one counterweight 15 (7) are further connected to each other by support means (10) and that the first sensor (5a) is located between the drive means (8) and the elevator car (6) and the second sensor (5b) ) is located between the support means (10) and the elevator car (6); or 20 (iv) a first sensor (5a) is located between the traction means (8) and the roof of the elevator car (6) and a second sensor (5b) is located between the traction means (8) and the bottom of the elevator car (6).

2. Patenttivaatimuksen 1 mukainen järjestely, 25 tunnettu siitä, että ensimmäiseen voimaan (Fi) edelleen vaikuttaa vähintään yksi seuraavista: lepo- tj- q kitka, liikekitka, ensimmäisen massan (Mi) kiihtyvyys. (MArrangement according to Claim 1, characterized in that the first force (Fi) is further influenced by at least one of the following: resting friction, motion friction, acceleration of the first mass (Mi). (M

3. Jonkin patenttivaatimuksista 1-2 mukainen ? järjestely, tunnettu siitä, että toiseen voimaan oo 30 (F2) vaikuttaa vähintään yksi seuraavista: toinen mas- ϊ sa (M2) , lepokitka, liikekitka, toisen massan (M2) kiihtyvyys, köyden jännityksen aikaansaava laite, ooAccording to any one of claims 1-2? arrangement characterized in that the second force oo 30 (F2) is affected by at least one of the following: one mass (M2), rest friction, motion friction, acceleration of another mass (M2), rope tensioning device, oo

4. Jonkin patenttivaatimuksista 1-3 mukainen ^ järjestely, tunnettu siitä, että järjestely käsit- O ^ 35 tää ensimmäisen anturin (5a) ja toisen anturin (5b) yhden seuraavista suureista mittaamiseksi: kuorma, paine, etäisyys, vastus.Arrangement according to one of Claims 1 to 3, characterized in that the arrangement comprises a first sensor (5a) and a second sensor (5b) for measuring one of the following quantities: load, pressure, distance, resistance.

5. Jonkin patenttivaatimuksista 1-4 mukainen järjestely, tunnettu siitä, että vetovälineet (8) 5 käsittävät vähintään yhden seuraavista välineistä: köysi, kaapeli, ketju tai hihna. 't δ c\j i δ i oo CVJ X cc CL 1^ 00 CO CD CVJ δ CVJArrangement according to one of Claims 1 to 4, characterized in that the pulling means (8) 5 comprise at least one of the following: a rope, a cable, a chain or a belt. 't δ c \ j i δ i oo CVJ X cc CL 1 ^ 00 CO CD CVJ δ CVJ