WO2022167712A1

WO2022167712A1 - Connecting part and guide rail part for an elevator and method for assembling guide rail

Info

Publication number: WO2022167712A1
Application number: PCT/FI2021/050068
Authority: WO
Inventors: Sami RANTANEN; Henri KOKKO; Marco GUGLIELMO
Original assignee: Kone Corporation
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2022-08-11

Abstract

The connecting part (1) for use in a joint that connects two guide rail parts (2a, 2b) of a guide rail (2, 12) of an elevator is configured to be inserted into cavities (6) of guide rail parts (2a, 2b) and comprises one or more bulges (4a, 4b, 4c, 4d), at least one of the bulges (4a, 4b, 4c, 4d) being configured to engage the connecting part (1) with an inner wall of the cavity (6) of a first guide rail part (2a), and at least one of the bulges (4a, 4b, 4c, 4d) being configured to engage the connecting part (1) with an inner wall of the cavity (6) of a second guide rail part (2b).

Description

CONNECTING PART AND GUIDE RAIL PART FOR AN ELEVATOR AND METHOD FOR ASSEMBLING GUIDE RAIL

Technical field

The present invention relates to a connecting part for use in a joint that connects two guide rail parts of an elevator in accordance with the preamble of claim 1 . The invention also concerns a guide rail part for a guide rail and a method for assembling a guide rail, as defined in the other independent claims. The invention further concerns a guide rail arrangement and an elevator.

Background

Most elevators are provided with vertical guide rails, which are used for guiding an elevator car and/or a counterweight. Often the elevator is provided with own guides rail for both the elevator car and the counterweight. The guide rails run in the vertical direction from the bottom to the top of the shaft. Typically, each guide rail consists of several vertical segments. The guide rails are assembled by connecting those segments to each other on-site. A typical guide rail has a T-shaped cross-sectional profile. The arms of the profile are used for attaching the guide rail to the elevator shaft, usually via guide rail brackets. The stem of the profile forms a nose that functions as support surfaces for the elevator car or the counterweight. The guide rail segments may be hollow parts. Such hollow guide rail parts can be attached to each other by inserting into two successive guide rail parts a connecting part, which can be called as a fishplate. The ends of the guide rail parts are provided with holes and the fishplate is provided with corresponding holes. Bolts are inserted through the holes and washers and nuts are used for forming a bolt joint.

The bolt joints have some drawbacks. One of the drawbacks is that there is a limited installation space around the bolts. The gap between the bolt and the nose of the guide rail is narrow, which makes the use of a spanner and a socket difficult.

Another problem is that there is often a need to handle the ends of the guide rails with an abrasive tool to remove notches from the joint. To ensure that the guide rail parts are not damaged, the work should be carried out using hand tools. However, to some fitters, it is tempting to use a grinding machine, which is much faster, but can damage the galvanization of the guide rails. Also, it is challenging to maintain alignment of the parts of the joint during assembly and due to the tolerances of the guide rails and the fishplate, a gap can be formed between the guide rail parts. This may affect the performance of the guide rails.

Summary

An object of the present invention is to provide an improved connecting part for use in a joint that connects a first guide rail part of a guide rail of an elevator to a second guide rail part of the guide rail, the connecting part having a first end that is configured to be inserted into a cavity of the first guide rail part and a second end that is configured to be inserted into a cavity of the second guide rail part. The characterizing features of the connecting part according to the invention are given in the characterizing part of claim 1 . Another object of the invention is to provide an improved guide rail part for a guide rail of an elevator. The characterizing features of the guide rail part are given in claim 21. Still another object of the invention is to provide an improved method for assembling a guide rail. The characterizing features of the method are given in the characterizing part of claim 25. Further objects of the invention are to provide an improved guide rail arrangement and an elevator in accordance with claims 23 and 24, respectively.

The connecting part according to the invention comprises at least one bulge arranged on a surface of the connecting part, wherein at least one of the bulges of the connecting part is configured to engage the connecting part with an inner wall of the cavity of the first guide rail part, and at least one of the bulges is configured to engage the connecting part with an inner wall of the cavity of the second guide rail part.

The guide rail part according to the invention is configured to receive a connecting part defined above.

The connecting part according to the invention provides several benefits. The at least one bulge can be configured to deform the guide rail part and/or to be deformed when the connecting part is inserted into the guide rail part. Due to the at least one bulge, the connecting part is firmly engaged with guide rail parts without a need to use bolts, nuts and washers. This saves time and simplifies the assembly work of guide rails. Also the costs are reduced as less parts are needed. Also the manufacturing process of the connecting part itself is simplified as bolt holes are not needed. Further, the parts of the joints are self-aligning, which makes the assembly work easier and also improves the quality of the joint.

The method according to the invention comprises the steps of providing a connecting part defined above, providing a first guide rail part defined above, and providing a second guide rail part defined above, wherein the first end of the connecting part is inserted into the first guide rail part and the second end of the connecting part is engaged with the second guide rail part.

According to an embodiment of the invention the at least one bulge is configured to make at least one outer dimension of the connecting part locally greater than the respective inner dimension of the respective guide rail part.

According to an embodiment of the invention, the at least one bulge has an elongated shape and the longitudinal direction of the bulge is parallel with the longitudinal direction of the connecting part. There is thus an elongated contact surface between the connecting part and the respective guide rail part in an assembled joint. This ensures sufficient friction in the joint, while excessive deformation of the guide rail part is avoided.

According to an embodiment of the invention, the cross-sectional profile of the at least one bulge is semicircle. This facilitates smooth joining of the parts of the joint and ensures uniform deformation of the parts.

According to an embodiment of the invention, the at least one bulge is chamfered or rounded so that the thickness of the bulge decreases towards the end that is configured to be first inserted into the cavity of the respective guide rail part. The shape of the leading ends of the bulges facilitates joining of the connecting part and the guide rail part.

According to an embodiment of the invention, the height of the at least one bulge is 0.15-2.0 mm. The height can be in the range of 0.25-0.75 mm.

According to an embodiment of the invention, the width of the at least one bulge is 0.5-10 mm. The width can be in the range of 1 .0-3.0 mm. According to an embodiment of the invention, the at least one bulge is configured to protrude 15-60 mm into the respective guide rail part. A length in said range ensures sufficient strength of the joint while allowing convenient assembly work.

According to an embodiment of the invention, the connecting part has a T- shaped cross-sectional profile. A T-shaped connecting part is suitable for connecting hollow T-shaped guide rail parts.

According to an embodiment of the invention, the at least one bulge is arranged on a surface of one of the arms of the T-shaped profile. All the bulges of the connecting part can be arranged on the surfaces of the arms of the T- shaped profile. By arranging the bulges on the surfaces of the arms, deformation of the stem of the guide rail part, which functions as a guide surface, is minimized and good performance of the guide rail is thus ensured.

According to an embodiment of the invention, the connecting part comprises two or more bulges, at least one of the bulges being arranged on a first surface of the connecting part and at least one of the bulges being arranged on a second surface of the connecting part, the first surface and the second surface facing opposite directions. Bulges arranged on opposite surfaces improve selfaligning properties of the connecting part.

According to an embodiment of the invention, the connecting part comprises at least four bulges and at least four of the bulges are configured to protrude into the first guide rail part and at least four of the bulges are configured to protrude into the second guide rail part. The connecting part can comprise at least eight bulges, wherein at least eight bulges are configured to protrude into both the first guide rail part and the second guide rail part. A greater number of bulges increases the friction between the parts of the joint while avoiding excessive local deformation of the parts.

According to an embodiment of the invention, the connecting part is mirror symmetric about a longitudinal center plane. This ensures good alignment of the connecting part.

According to an embodiment of the invention, the connecting part comprises a first stopper surface that is configured to prevent inserting the first end of the connecting part into the first guide rail part beyond a predetermined limit, and a second stopper surface that is configured to prevent inserting the second end of the connecting part into the second guide rail part beyond a predetermined limit. The stopper surfaces can be arranged in a protrusion extending outwards in a transversal direction of the connecting part. The stopper surfaces facilitate assembly of the guide rail and ensure that the connecting part is sufficiently engaged with both the first guide rail part and the second guide rail part.

According to an embodiment of the invention, the guide rail part comprises a recess that is configured to receive a protrusion defined above. The recess allows the ends of two guide rail parts to be arranged against each other.

According to an embodiment of the invention, the connecting part is made of a metal or an alloy. The connecting part can be made of, for instance, an aluminum alloy.

A guide rail arrangement according to the invention comprises a connecting part defined above, and first and second guide rail parts as defined above.

An elevator according to the invention comprises a guide rail arrangement defined above.

Brief description of the drawings

Embodiments of the invention are described below in more detail with reference to the accompanying drawings, in which

Fig. 1 shows schematically a simplified view of an elevator,

Fig. 2 shows a connecting part according to an embodiment of the invention,

Fig. 3 shows the connecting part of Fig. 1 from another direction,

Fig. 4 shows a detail of the connecting part of Fig. 1 ,

Fig. 5 shows a guide rail part according to an embodiment of the invention,

Fig. 6 shows the connecting part of Fig. 1 inserted into the guide rail part of Fig. 5, and

Fig. 7 shows two guide rail parts connected by means of a connecting part. Detailed description of embodiments of the invention

Figure 1 shows a simplified schematic view of an elevator. The elevator comprises an elevator car 11 and a counterweight 17 which are configured to be moved in the vertical direction in a shaft 10. For the sake of clarity, many parts of the elevator, such as end buffers for the elevator car 11 and the counterweight 17 have been omitted in figure 1. The elevator car 11 is connected to the counterweight 17 via a hoisting member 13. The hoisting member 13 can be, for example, a steel wire, a belt, such as a toothed belt or a flat belt, a carbon fiber rope or a coated rope. The elevator can comprise several hoisting members 13. The elevator car 11 and the counterweight 17 are connected to each other in such a way that they move to opposite directions in respect of each other. The elevator is further provided with a motor 14. The motor 14 is preferably an electric motor. The motor 14 drives a sheave (not shown). The sheave can be connected to the motor 14 either directly or via a gear. As the sheave rotates, the hoisting member 13 moves and the elevator car 11 and the counterweight 17 are moved. In the example of figure 1 , each end of the hoisting member 13 is fixed to the upper end of the shaft 10. The elevator car 11 is provided with two pulleys, of which only one pulley 15 is shown in figure 1. In the example of figure 1 , the pulleys are arranged below the elevator car 1 . The hoisting member 13 is engaged with the pulleys, which are configured to rotate freely about a rotation axis. The counterweight 17 is provided with a pulley 16 which is engaged with the hoisting member 13. Also the pulley 16 of the counterweight 17 is configured to rotate freely about a rotation axis. The sheave, the pulleys 15, 16 and the hoisting member 13 form the roping system of the elevator.

It should be noted that figure 1 shows only an example of a roping system of an elevator, and the hoisting member 13 could be arranged in many alternative ways. For example, the elevator car 11 could be provided with a single pulley. The counterweight 17 could be provided with more than one pulleys. A first end of the hoisting member 13 could be attached to the elevator car 11 and a second end of the hoisting member 13 could be attached to the counterweight 17. The hoisting member 4 could be guided around the sheave of the motor 14 twice.

In the example of figure 1 , the motor 14 is arranged in the shaft 10. The elevator is thus a machine-room-less elevator. However, the elevator could also be provided with a machine room located above the shaft 10 and the motor could be arranged in the machine room.

The elevator further comprises guide rails 2, 12. The guide rails 2, 12 are supporting structures that run in the vertical direction in the elevator shaft 10. The guide rails 2, 12 guide the vertical movement of the elevator car 11 and the counterweight 17. Also, the safety gear of the elevator cooperates with the guide rails 12 and the clamping jaws of the safety gear close around the guide and stop an overspeeding elevator car. The elevator of figure 1 comprises a pair of guide rails 2 that guide the counterweight 17 and another pair of guide rails 12 that guide the elevator car 11 .

A guide rail 2, 12 typically has a T-shaped cross-sectional profile. The guide rail 2, 12 is attached to the walls of the shaft 10 via the arms of the T-shaped profile, while the side surfaces of the stem function as guide surfaces for the car 11 or the counterweight 17. The guide rail 2, 12 is typically assembled by connecting short segments to each other. The segments are hereinafter called as guide rail parts. Assembling of a guide rail 2, 12 typically starts from the bottom of the shaft 10. The lowermost guide rail part is attached to the wall of the shaft and then the following guide rail part is attached to the lower guide rail part and to the wall of the shaft. The assembled guide rail section can be used as a support for a movable assembly platform, which can be moved upwards as the assembly work progresses.

Figure 5 shows an example of a guide rail part 2a. In the embodiment of figure 5, the guide rail part 2a is made of sheet metal, such as steel. The guide rail part 2a has a T-shaped profile. The guide rail part 2a is configured to be attached to the wall of an elevator shaft via the arms 3, 4 of the profile. The side surfaces of the stem 5 of the profile function as guide surfaces for a counterweight 17 of an elevator. The guide rail part 2a is a hollow profile and both ends of the profile are open. A cavity 6 is thus formed within the guide rail part 2a. The guide rail 2 is assembled using a plurality of identical or similar guide rail parts 2a. At the ends of the guide rail the ends of the guide rail parts 2a could be closed.

Two guide rail parts 2a, 2b are connected to each other using a connecting part 1. A connecting part 1 according to an embodiment of the invention can be seen in figures 2 and 3. Figure 4 shows an enlarged view of some details of the connecting part 1 . The connecting part 1 has a first end 1 a and a second end 1 b. The first end 1 a of the connecting part 1a is configured to be inserted into a guide rail part 2a. The second end 1 b of the connecting part 1 is configured to be inserted into another guide rail part 2b. In a joint formed by the connecting part 1 and two guide rail parts 2a, 2b, the guide rail parts can be referred to as a first guide rail part 2a and a second guide rail part 2b. Figure 7 shows a joint formed by a connecting part 1 , a first guide rail part 2a and a second guide rail part 2b.

The shape of the connecting part 1 corresponds to the shape of the cavity within the guide rail 2. In the embodiment of the figures, the cavity of the guide rail 2 has a T-shaped profile and also the cross-sectional profile of the connecting part 1 is thus substantially T-shaped. The connecting part 1 is dimensioned so that it can be inserted into the two guide rail parts 2a, 2b. Outer dimensions of the connecting part 1 are mainly slightly smaller than the inner dimensions of the cavities 6 of the guide rail parts 2a, 2b. Part of the connecting part 1 can thus slide easily into the guide rail parts 2a, 2b.

For forming a rigid joint between two guide rail parts 2a, 2b, the connecting part 1 is provided with one or more bulges 4a, 4b, 4c, 4d. In the embodiment of the figures, the connecting part 1 is provided with a plurality of bulges 4a, 4b, 4c, 4d. At least one bulge is configured to be engaged with a first guide rail part 2a and at least one bulge is configured to be engaged with a second guide rail part 2b. Each bulge 4a, 4b, 4c, 4d is arranged on a surface of the connecting part 1 . The bulges 4a, 4b, 4c, 4d are configured to make at least one outer dimension of the connecting part 1 locally greater than the respective inner dimension of the respective guide rail part 2a, 2b. Each bulge 4a, 4b, 4c, 4d is thus configured to deform a guide rail part 2a, 2b when the connecting part 1 is inserted into the guide rail part 2a, 2b. Alternatively, or in addition, the bulge 4a, 4b, 4c, 4d can be deformed when inserted into the cavity 6 of the guide rail part 2a, 2b.

Because of the deforming of the guide rail part 2a, 2b and/or the bulges 4a, 4b, 4c, 4d, a tight connection between the connecting part 1 and the guide rail part 2a, 2b is formed. The guide rail part 2a, 2b and the connecting part 1 are kept together by the friction force created by the compression. In the embodiment of the figures, each of the bulges 4a, 4b, 4c, 4d has an elongated shape. The longitudinal directions of the bulges 4a, 4b, 4c, 4d are parallel to the longitudinal direction of the connecting part 1. The longitudinal direction of the connecting part 1 is parallel to the longitudinal direction of the guide rail parts 2a, 2b in an assembled state of a guide rail. In the embodiment of the figures, each bulge 4a, 4b, 4c, 4d extends to the area of two guide rail parts 2a, 2b in the assembled state of the guide rail. However, the bulges could also be configured so that each bulge is engaged only with one guide rail part. The cross-sectional shape of each bulge 4a, 4b, 4c, 4d is semicircle. The bulges 4a, 4b, 4c, 4d do thus not have sharp edges. This ensures that the bulges exert a uniform force on the guide rail parts 2a, 2b. The ends of the bulges are chamfered. The thickness of the bulges thus reduces towards the ends, which facilitates the assembly of the connecting part 1 and the guide rail parts 2, 2a. If separate bulges were provided for the two guide rail parts 2a, 2b, it would be sufficient to have only the leading ends, i.e. those ends of the bulges that are first inserted into the guide rail parts, chamfered. Instead of chamfered ends, the ends could be rounded.

In the embodiment of the figures, the height of the bulges is 0.35 mm and the width is 1 .5 mm. Suitable ranges for the height are 0.15-2.0 mm, or 0.25-0.75 mm. Suitable ranges for the width of the bulges are 0.5-10 mm, or 1.0-3.0 mm. Each bulge can protrude 15-60 mm into the respective guide rail part 2a, 2b in an assembled state.

In the embodiment of the figures, all the bulges 4a, 4b, 4c, 4d are arranged on the surfaces of the arms of the T-shaped profile of the connecting part 1. Because of this, mainly the arms 3, 4 of the guide rails are deformed and the stem 5, which forms the guide surfaces, retains its shape. This ensures smooth functioning of the guide surfaces.

In the embodiment of the figures, the bulges 4a, 4b, 4c, 4d are arranged on different surfaces of the connecting part 1. The bulges are arranged on surfaces that face opposite directions in respect of each other. This ensures that the connecting part 1 is self-aligned when inserted into a guide rail part 2a, 2b. In the embodiment of the figures, the connecting part 1 is mirror symmetric about a longitudinal center plane. This further improves the selfaligning properties of the connecting part 1 . The connecting part 1 is provided with a first stopper surface 7a and with a second stopper surface 7b. The first stopper surface 7a cooperates with the first guide rail part 2a and is configured to prevent inserting the connecting part 1 into the first guide rail part 2a beyond a predetermined limit. Similarly, the second stopper surface 7b cooperates with the second guide rail part 2b and is configured to prevent inserting the connecting part 1 into the second guide rail part 2b beyond a predetermined limit. When the first stopper surface 7a is engaged with a mating surface arranged in the first guide rail part 2a, half of the connecting part 1 is inserted into the first guide rail part 2a. Similarly, when the second stopper surface 7b is engaged with a mating surface arranged in the second guide rail part 2b, half of the connecting part 1 is inserted into the second guide rail part 2b.

In the embodiment of the figures, the first and the second stopper surfaces 7a, 7b are arranged in a protrusion 7 that extends outwards from the connecting part 1 in a transversal direction. The protrusion 7 is arranged symmetrically about a transversal center plane of the connecting part 1 . The connecting part 1 is provided with two protrusions 7, which are arranged symmetrically about a longitudinal center plane of the connecting part 1 .

The guide rail parts 2a, 2b are provided with recesses 8, which are configured to receive the protrusions 7 of the connecting part 1 . As shown in figure 7, the recesses 8 allow the connecting part 1 to be inserted into the first and the second guide rail part 2a, 2b so that the ends of the guide rail parts 2a, 2b contact each other, at least within the limits of the manufacturing tolerances. Smooth guide surfaces without substantial gaps are thus formed.

In the embodiment of the figures, the connecting part 1 is a solid piece. The connecting part 1 can be made of aluminum. An example of a suitable alloy is EN AW-6060. A suitable temper for the alloy is T5, which means that the alloy is cooled from an elevated temperature forming operation and artificially aged. However, also other alloys and/or tempers could be used. The connecting part can be manufactured by investment casting. In investment casting a shell is formed around a wax pattern. Different materials can be used for forming the shell, but in practice a ceramic is used for casting aluminum alloys. The wax pattern is then removed by melting major part of the wax and by burning any remaining wax in a furnace. The mold is then preheated and filled with molten alloy. A sufficiently cooled casting is then removed by breaking the mold. An alternative manufacturing method is high-pressure die casting, where molten metal is injected into dies under high pressure. The dies comprise a cover die half and an ejector die half. The dies are typically made of hardened tool steels.

The connecting part 1 could also be made of steel or some other alloy.

In the method according to the invention, a guide rail is assembled using guide rail parts 2a, 2b and connecting parts 1 according to the invention. According to an embodiment of the invention, a first guide rail part 2a is first attached to the elevator shaft 10. The first guide rail part 2a can be the lowermost part of a guide rail 2 of the counterweight 17. The first end 1 a of the connecting part 1 is then inserted into the first guide rail part 2a. Due to the bulges 4a, 4b, 4c, 4d, some force is required for fully inserting the connecting part 1 into the first guide rail part 2a. For instance a hammer can be used for applying a sufficient force on the connecting part 1 .

After installing the connecting part 1 into the first guide rail part 2a, a second guide rail part 2b is connected to the connecting part 1. The cavity 6 of the second guide rail part 2b is arranged around the second end 1 b of the connecting part 1 and the second guide rail part 2b is then forced downwards until it fully encircles the upper half of the connecting part 1 . Again, a hammer may be used for applying a sufficient force on the second guide rail part 2b for assembling it.

The assembly of the guide rail is continued by inserting a following connecting part 1 into the free end of the second guide rail part 2b, after which a following guide rail part is engaged with the connecting part.

The expressions “first end 1a”, “second end 1 b”, first guide rail part 2a”, and “second guide rail part 2b” have been used above to assist especially in describing how the different parts of joint are attached to each other. However, in the embodiment of the figures, the connecting part 1 is symmetric about a transversal plane, and the first end 1 a and the second end 1 b are thus identical. Also the first guide rail part 2a and the second guide rail part 2b are identical with each other. However, it is also possible that the first end 1a and the second end 1 b of the connecting part 1 and/or the first and the second guide rail parts 2a, 2b are not identical with each other but only similar. The parts and the method according to the invention have been described above in connection with the guide rails 2 of a counterweight 17. However, the invention could also be applied to the guide rails 12 of the elevator car 11 , although safety requirements may limit the applicability of the invention to the guide rails 12 of the elevator car 11 . The guide rails 12 of the elevator car 11 normally cooperate with safety devices of the elevator car, and therefore the use of hollow guide rails may be excluded.

It will be appreciated by a person skilled in the art that the invention is not limited to the embodiments described above, but may vary within the scope of the appended claims.

Claims

Claims:

1. A connecting part (1 ) for use in a joint that connects a first guide rail part (2a) of a guide rail (2, 12) of an elevator to a second guide rail part (2b) of the guide rail (2, 12), wherein the connecting part (1 ) has a first end (1 a) that is configured to be inserted into a cavity (6) of the first guide rail part (2a) and a second end (1 b) that is configured to be inserted into a cavity (6) of the second guide rail part (2b), characterized in that the connecting part (1 ) comprises at least one bulge (4a, 4b, 4c, 4d) arranged on a surface of the connecting part (1 ), wherein at least one of the bulges (4a, 4b, 4c, 4d) of the connecting part (1 ) is configured to engage the connecting part (1 ) with an inner wall of the cavity (6) of the first guide rail part (2a), and at least one of the bulges (4a, 4b, 4c, 4d) is configured to engage the connecting part (1 ) with an inner wall of the cavity (6) of the second guide rail part (2b).

2. A connecting part (1 ) according to claim 1 , wherein the at least one bulge (4a, 4b, 4c, 4d) is configured to make at least one outer dimension of the connecting part (1 ) locally greater than the respective inner dimension of the respective guide rail part (2a, 2b).

3. A connecting part (1 ) according to claim 1 or 2, wherein the at least one bulge (4a, 4b, 4c, 4d) has an elongated shape and the longitudinal direction of the bulge (4a, 4b, 4c, 4d) is parallel with the longitudinal direction of the connecting part (1 ).

4. A connecting part (1 ) according to any of claims 1-3, wherein the cross- sectional profile of the at least one bulge (4a, 4b, 4c, 4d) is semicircle.

5. A connecting part (1 ) according to any of the preceding claims, wherein the at least one bulge (4a, 4b, 4c, 4d) is chamfered or rounded so that the thickness of the bulge (4a, 4b, 4c, 4d) decreases towards the end that is configured to be first inserted into the cavity (6) of the respective guide rail part (2a, 2b).

6. A connecting part (1 ) according to any of the preceding claims, wherein the height of the at least one bulge (4a, 4b, 4c, 4d) is 0.15-2.0 mm.

7. A connecting part (1 ) according to claim 6, wherein the height is 0.25-0.75 mm.

8. A connecting part (1 ) according to any of the preceding claims, wherein the width of the at least one bulge (4a, 4b, 4c, 4d) is 0.5-10 mm.

9. A connecting part (1 ) according to claim 8, wherein the width is 1.0-3.0 mm.

10. A connecting part (1 ) according to any of the preceding claims, wherein the at least one bulge (4a, 4b, 4c, 4d) is configured to protrude 15-60 mm into the respective guide rail part (2a, 2b).

11 . A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) has a T-shaped cross-sectional profile.

12. A connecting part (1 ) according to claim 11 , wherein the at least one bulge (4a, 4b, 4c, 4d) is arranged on a surface of one of the arms of the T-shaped profile.

13. A connecting part (1 ) according to claim 11 or 12, wherein all the bulges (4a, 4b, 4c, 4d) of the connecting part (1 ) are arranged on the surfaces of the arms of the T-shaped profile.

14. A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) comprises two or more bulges (4a, 4b, 4c, 4d), at least one of the bulges (4a, 4b, 4c, 4d) being arranged on a first surface of the connecting part (1 ) and at least one of the bulges (4a, 4b, 4c, 4d) being arranged on a second surface of the connecting part (1 ), the first surface and the second surface facing opposite directions.

15. A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) comprises at least four bulges (4a, 4b, 4c, 4d) and at least four of the bulges (4a, 4b, 4c, 4d) are configured to protrude into the first guide rail part (2a) and at least four of the bulges (4a, 4b, 4c, 4d) are configured to protrude into the second guide rail part (2b).

16. A connecting part (1 ) according to claim 14, wherein the connecting part (1 ) comprises at least eight bulges (4a, 4b, 4c, 4d) and at least eight of the bulges (4a, 4b, 4c, 4d) are configured to protrude into the first guide rail 15 part (2a) and at least eight of the bulges (4a, 4b, 4c, 4d) are configured to protrude into the second guide rail part (2b).

17. A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) is mirror symmetric about a longitudinal center plane.

18. A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) comprises a first stopper surface (7a) that is configured to prevent inserting the first end (1 a) of the connecting part (1 ) into the first guide rail part (2a) beyond a predetermined limit, and a second stopper surface (7b) that is configured to prevent inserting the second end (1 b) of the connecting part (1 ) into the second guide rail part (2b) beyond a predetermined limit.

19. A connecting part (1 ) according to claim 18, wherein the first stopper surface (7a) and the second stopper surface (7b) are arranged in a protrusion (7) extending outwards in a transversal direction of the connecting part (1 ).

20. A connecting part (1 ) according to any of the preceding claims, wherein the connecting part (1 ) is made of a metal or an alloy.

21 .A guide rail part (2a, 2b) for a guide rail (2, 12) of an elevator, wherein the guide rail part (2, 2a) is configured to receive a connecting part (1 ) according to any of the preceding claims.

22. A guide rail part (2a, 2b) according to claim 21 , wherein the guide rail part (2a, 2b) is configured to receive a connecting part (1 ) according to claim 19 and comprises a recess (8) for receiving the protrusion (7) of the connecting part (1 ).

23. A guide rail arrangement for an elevator, the guide rail arrangement comprising a connecting part (1 ) according to any of claims 1-20, a first guide rail part (2a) according to claim 21 or 22, and a second guide rail part (2b) according to claim 21 or 22.

24. An elevator comprising a guide rail arrangement according to claim 23.

25. A method for assembling a guide rail (2, 12) of an elevator, wherein the method comprises the steps of providing a connecting part (1 ) according to 16 any of claims 1-20, providing a first guide rail part (2a) according to claim 21 or 22, and providing a second guide rail part (2b) according to claim 21 or 22, wherein the first (1a) end of the connecting part (1 ) is inserted into the first guide rail part (2a) and the second end (1 b) of the connecting part (1 ) is engaged with the second guide rail part (2b).