An elevator installation with a pulley box

Abstract

An elevator installation (100) is disclosed herein. The elevator installation (100) comprises a counterweight unit (106), an elevator car (102) and at least one machine pulley (118). The at least one machine pulley (118) is positioned on a top portion of the at least one car guide rail (104) of the elevator installation (100) and is guiding a traction medium (114) to move the counterweight unit (106) and the elevator car (102). The counterweight unit (106) comprises a supporting frame (110) and a pulley box (112). The pulley box (112) comprises at least one pulley (116) connected with the at least one machine pulley (118) via the traction medium (114). Herein, a pulley rotational axis (P-P') of the at least one pulley (116) is parallel to a machine pulley rotational axis (M-M') and is horizontally offset with respect to a centre of gravity of the counterweight unit (106).

Description

[0001]

[0002] AN ELEVATOR INSTALLATION WITH A PULLEY BOX

[0003] The present invention relates to elevator installations and more particularly, an elevator installation with a pulley box. Further, it relates to a pulley box for an elevator installation.

[0004] Elevator installations are an essential part of multi-storey buildings, such as commercial or residential buildings, for transporting persons / goods between different floors. The elevator installation usually comprises an elevator shaft, an elevator car, a counterweight unit, and at least one guide rail. The at least one guide rail is positioned within the elevator shaft to guide the elevator car and the counterweight unit, such that the elevator car and the counterweight unit are moved in opposite directions. Herein, the movement of the elevator car and the counterweight unit is supported by a traction medium. In some elevator installations, the traction medium is guided over a counterweight pulley. The counterweight pulley is connected with a machine pulley and one or more pulleys of the elevator car via the traction medium to drive the elevator car. Herein, the counterweight pulley is positioned in a pulley box mounted on the counterweight unit, and the machine pulley is supported on a top portion of the guide rail. Further, end connectors are supported on the guide rails to support the ends of the traction medium.

[0005] During the operation of the elevator installation when the counterweight unit is in a headroom region or moving towards the headroom region, an angle between a vertical axis of the counterweight pulley and the traction medium connected to the end connector, is increased. Herein, an angle between the vertical axis of the counterweight pulley and the traction medium connected to the machine pulley is also increased. Due to the increase in such angles, greater forces are acting on the end connector. Such forces can impact the performance and service life of the end connector and the elevator installation. This further increases the overall complexity of the elevator installation.

[0006]

[0007] CN206521190U discloses an eccentric counterweight wheel arrangement structure. The eccentric counterweight wheel arrangement structure includes a counterweight wheel, an eccentric wheel shaft, an upper side plate connected to one end of the eccentric wheel shaft, and a lower side plate connected to the other end of the eccentric wheel shaft. Herein, the eccentric wheel shaft is installed through the centre of the counterweight wheel. However, there is no provision to reduce the forces acting on the end connector of the elevator installation.

[0008] US 2021 / 0395045 Al discloses an elevator which includes an elevator car movable in a shaft and a counterweight. The counterweight is connected by suspension apparatus guided over deflecting rollers of a deflecting unit. The counterweight deflecting unit includes a cover arrangement, for covering the deflecting rollers, that is a plastic folding part formed from an erectable blank. The blank has a cover and side walls surrounded by folding lines or edges, wherein the cover and the side walls, in a starting position, lie on a common plane and wherein the cover and the side walls, in an end position, form a cover portion, a front side wall, a rear side wall and transverse side walls, the side walls adjoining the cover portion at right angles.

[0009] CN109516352B discloses an elevator counterweight device. Two or more pairs of counterweight guide shoes are mounted on a counterweight frame; counterweight blocks are fixedly mounted in the counterweight frame; a hanging steel wire rope and an upper frame piece of the counterweight frame are fixedly connected to a hanging point or connected to the hanging point through counterweight wheels; one end of a single compensation chain / cable or one ends of two compensation chains / cables with different unit weights are hung on a lower frame piece of the counterweight frame; the other end of the single compensation chain / cable or the other ends of the two compensation chains / cables with the different unit weights are hung to the bottom face of a car; the hanging point and a counterweight gravity center line are bias; the hanging point and a suspension point

[0010]

[0011] of the single compensation chain / cable on the lower frame piece of the counterweight frame are located on the same side of the counterweight gravity center line; or the hanging point and a suspension point of the heavy one of the two compensation chains / cables with the different unit weights on the lower frame piece of the counterweight frame are located on the same side of the counterweight gravity center line. The elevator counterweight device can effectively solve the problem of abrasion of the counterweight guide shoes when a counterweight is configured with the unbalanced compensation chains / cables.

[0012] Therefore, there is a desire to develop an elevator installation that can eliminate one or more shortcomings associated with the abovementioned elevator installations.

[0013] According to a first aspect of the invention, an elevator installation is disclosed. The elevator installation comprises a counterweight unit, an elevator car, and at least one machine pulley. The elevator car is coupled to the counterweight unit via a traction medium and guided by at least one car guide rail to move within an elevator shaft. The at least one machine pulley is positioned on a top portion of the at least one car guide rail of the elevator installation and is guiding the traction medium to move the counterweight unit and the elevator car in opposite directions. The counterweight unit has a supporting frame, and a pulley box mounted on the supporting frame. The pulley box comprises at least one pulley positioned on a top portion of the counterweight unit and connected with the at least one machine pulley via the traction medium. Herein, a pulley rotational axis of the at least one pulley is parallel to a machine pulley rotational axis of the at least one machine pulley, and the pulley rotational axis is horizontally offset with respect to a centre of gravity of the counterweight unit. The centre of gravity (CG) of the counterweight unit may refer to a weighted average of the centres of gravity of sub-components of the counterweight unit, and may be represented as a point where the total weight of the counterweight unit can be considered to act. The centre of gravity (CG) may be centre of gravity of the assembled counterweight unit. This measure reduces the

[0014]

[0015] angles between a traction medium and a vertical axis of the at least one pulley, which further reduces one or more forces acting on an end connector.

[0016] The expressions “vertical” and “horizontal” refer to an operational configuration of the elevator installation. A vertical direction is generally aligned with the direction of gravity, and a horizontal direction is orthogonal to the vertical direction.

[0017] According to a second aspect of the invention, a counterweight unit for an elevator installation is disclosed. The counterweight unit comprises a supporting frame and a pulley box mounted on the supporting frame. Herein, the pulley box comprises at least one pulley positioned on a top portion of the counterweight unit and adapted to be connected with at least one machine pulley via a traction medium of the elevator installation. The counterweight unit is configured such that in an operational configuration of the elevator installation a pulley rotational axis of the at least one pulley is parallel to a machine pulley rotational axis of the at least one machine pulley. Further, the pulley rotational axis is horizontally offset with respect to a centre of gravity of the counterweight unit.

[0018] The pulley rotational axis of the at least one pulley extends between a central horizontal axis of the counterweight unit and the elevator car, and further extends parallel to the central horizontal axis. Herein, the central horizontal axis of the counterweight unit passes through the centre of gravity of the counterweight unit.

[0019] During the operation of the elevator installation, a first angle is formed between a pulley vertical axis of the pulley and the traction medium connected with the machine pulley. Further, a second angle is formed between the pulley vertical axis and the traction medium connected to the end connector supported on the guide rail. Herein, the offset position of the pulley rotational axis with respect to the centre of gravity of the counterweight unit moves the pulley towards the end connector which reduces the first angle and the second angle. Such a reduction in the first

[0020]

[0021] angle and the second angle reduces one or more forces acting on the end connector, especially when the counterweight unit is in a headroom region or moving towards the headroom region. This improves the performance and service life of the end connector and the elevator installation, which further reduces the overall complexity of the elevator installation.

[0022] Further, owing to the arrangement of the at least one pulley and the machine pulley, the load is uniformly distributed between the elevator car and the counterweight unit. This improves the overall stability of the elevator installation, which results in the smoother operation of the elevator installation.

[0023] Accordingly, the elevator installation of the present invention is effective, less complex, and easy to implement and use.

[0024] Features and advantages of particular embodiments are defined by the dependent claims and the overall disclosure.

[0025] In an embodiment, the pulley rotational axis of the at least one pulley is offset in the direction towards the elevator car with respect to the centre of gravity of the counterweight unit. A smaller size pulley can also be mounted in the pulley box at the offset with respect to the centre of gravity of the counterweight unit. This reduces the overall weight and complexity of the at least one pulley and the pulley box, which further reduces the overall cost associated with the at least one pulley.

[0026] In an embodiment, the at least one pulley is offset with respect to the centre of gravity such that a predefined distance is maintained between the pulley rotational axis and the centre of gravity.

[0027] In an embodiment, the elevator installation comprises a pair of idler car pulleys connected with the at least one machine pulley via the traction medium and

[0028]

[0029] positioned underneath a floor of the elevator car, such that the elevator car is underwrapped by the traction medium.

[0030] In case the idler car pulleys are alternatively positioned on a top portion of the elevator car, the height of the elevator shaft is required to be increased to provide the required headroom over the elevator car. A positioning of the the idler car pulleys underneath the floor of the elevator car eliminates the requirement of increasing the height of the elevator shaft. This results in a compact design of the elevator installation. If the idler car pulleys are positioned underneath the elevator car, there is enough space available on the top portion of the elevator car for one or more technicians. Thus, the one or more technicians can comfortably position themselves on the top portion of the elevator car during the maintenance of the elevator installation.

[0031] In an embodiment, the elevator car and the counterweight unit are 2:1-suspended. Such 2: 1 suspension has the advantage of reducing the torque that must be provided by the at least one machine pulley.

[0032] In an embodiment, the elevator installation comprises a machine mount, a supporting structure, and an end connector. The machine mount is adapted to accommodate the machine pulley. The supporting structure is positioned on the top portion of the at least one car guide rail to support the machine mount. Further, the end connector is coupled with the at least one car guide rail and is vertically positioned below the supporting structure. Herein, the implementation of the end connector supports the ends of the traction medium.

[0033] In an embodiment, the pulley box comprises a mounting structure and a dust cover. The mounting structure is mounted on the supporting frame. Further, the dust cover is mounted on the mounting structure to cover the at least one pulley.

[0034]

[0035] In an embodiment, the mounting structure comprises a plurality of receiving holes to mount the dust cover, such that each of a first mounting hole and a second mounting hole of the dust cover is aligned with a respective receiving hole of the mounting structure to mount the dust cover.

[0036] Advantageously, the implementation of the plurality of receiving holes, and the mounting holes facilitates the easy and accurate mounting of the dust cover on the mounting structure. Thus, the dust cover can be mounted on the mounting structure with minimal effort by aligning the first and second mounting holes with the respective receiving holes. After aligning the first and second mounting holes with the respective receiving holes, a plurality of fasteners are tightened to securely mount the dust cover.

[0037] In an embodiment, the mounting structure comprises a shaft to support the at least one pulley. Further, the at least one pulley is rotatably mounted on the shaft of the mounting structure. Herein, the shaft is adapted to be rotated with the rotation of the at least one pulley.

[0038] Advantageously, the shaft supports the at least one pulley by ensuring that the at least one pulley remains in an original mounting position during the operation of the elevator installation. This improves the stability of the at least one pulley. Further, the shaft is formed of high-strength material, such that the shaft can sustain the high rotational forces.

[0039] The pulley box comprises a bottom retainer attached to the shaft of the mounting structure to cover at least a portion of the at least one pulley.

[0040] In an embodiment, the bottom retainer covers a bottom portion and a side portion of the at least one pulley such that other components of the elevator installation cannot interfere with the at least one pulley. Further, the implementation of the bottom retainer restricts the ingress of the external particles, such as dust or

[0041]

[0042] moisture, to the at least one pulley. This improves the overall safety and service life of the at least one pulley.

[0043] The pulley box comprises a side retainer attached to the bottom retainer, adjacent to the dust cover, to cover at least a portion of the at least one pulley.

[0044] Advantageously, the side retainer covers the side portion of the at least one pulley to prevent the at least one pulley from interfering with the other components of the elevator installation from the side portion. This improves the overall safety of the at least one pulley.

[0045] In an embodiment, the pulley box comprises a protection cover supported on the mounting structure in a parallel orientation relative to the dust cover.

[0046] Advantageously, the protection cover protects the at least one pulley from interfering with the other components of the elevator installation from the side portion. This improves the overall safety of the at least one pulley.

[0047] The dust cover may comprise a body and at least one pair of mounting members. The body may be positioned adjacent to the at least one pulley. The at least one pair of mounting members may orthogonally extend from each end of the body. The at least one pair of mounting members may comprise a first mounting member and a second mounting member. The first mounting member may comprise a first mounting hole positioned at a first predefined distance from the body. The second mounting member may be parallel to the first mounting member and may comprise a second mounting hole positioned at a second predefined distance from the body. Herein, the second predefined distance is typically greater than the first predefined distance.

[0048] The first mounting hole and the second mounting hole are generally formed at different predefined distances from the body, respectively. The implementation

[0049]

[0050] of the first mounting hole and the second mounting hole ensures that the dust cover is mounted on the mounting structure only in a specific orientation. Herein, the first mounting hole is only aligned with the corresponding receiving hole of the mounting structure, and the second mounting hole is only aligned with the other corresponding receiving hole of the mounting structure. Thus, the dust cover is accurately mounted in the specific orientation and at a desired position, with minimal effort. This makes the mounting of the dust cover easier as the mounting of the dust cover takes less time.

[0051] The term “under-wrapped” is referred to a condition in which the traction medium is disposed underneath the elevator car to connect with the pair of idler car pulleys positioned underneath the floor of the elevator car.

[0052] The term “central horizontal axis” is referred to an axis that passes through the centre of gravity of the counterweight unit and is orthogonal to a vertical movement of the counterweight unit within the elevator shaft and parallel to the pulley rotational axis.

[0053] The term “pulley rotational axis” is referred to a horizontal axis of the pulley passing through a centre of the pulley and about which a rotational movement of the pulley is defined.

[0054] The term “pulley vertical axis” is referred to an axis which is orthogonal to the horizontal axis, i.e., the pulley rotational axis, of the pulley.

[0055] Further advantages, features and details of the invention will become apparent from the following description and from the drawings, in which identical or functionally identical elements are denoted with identical reference signs. The drawings are merely schematic and not to scale.

[0056] Figure 1 illustrates a schematic view of an elevator installation;

[0057]

[0058] Figure 2 illustrates a perspective view of a counterweight unit of the elevator installation from Figure 1;

[0059] Figure 3 A illustrates a perspective view of a pulley box of the counterweight unit from Figure 2;

[0060] Figure 3B illustrates a side view of the pulley box of the counterweight unit from Figure 2;

[0061] Figure 3C illustrates a top view of the pulley box of the counterweight unit from Figure 2;

[0062] Figure 3D illustrates a perspective view of the pulley box mounted on the counterweight unit from Figure 2;

[0063] Figure 4 illustrates a side view of at least one pulley mounted on a mounting structure of the pulley box from Figure 3; and

[0064] Figure 5 illustrates a schematic view of the elevator installation from Figure 1.

[0065] Figure 1 illustrates a schematic view of an elevator installation 100. Figure 2 illustrates a perspective view of a counterweight unit 106 of the elevator installation 100 from Figure 1.

[0066] The elevator installation 100 is adapted to be installed in a building having a plurality of floors for transporting persons / goods between different floors. The elevator installation 100 comprises an elevator shaft (not shown), an elevator car 102, at least one car guide rail 104, 105, the counterweight unit 106, at least one

[0067]

[0068] machine pulley 118, a machine mount 136, a supporting structure 138, and a pair of end connectors 140, 141.

[0069] Herein, the elevator shaft is defined by a plurality of walls. Further, the elevator car 102 is adapted to be moved between the plurality of floors of the building, within the elevator shaft. As shown in Figure 1, two car guide rails 104, 105 are positioned within the elevator shaft to guide the elevator car 102 and the counterweight unit 106. Herein, two car guide rails 104, 105 are extended in a parallel orientation relative to each other. The elevator car 102 and the counterweight unit 106 are moved in opposite directions.

[0070] The elevator car 102 is coupled to the counterweight unit 106 via a traction medium 114. The elevator car 102 is guided by the car guide rails 104, 105 via a plurality of first guide shoes 103 to move the elevator car 102 within an elevator shaft. Herein, the traction medium 114 is one or more ropes, cables, chains, belts, or combinations thereof, without departing from the scope of the present invention.

[0071] The machine pulley 118 is positioned on a top portion of the car guide rail 104 of the elevator installation 100. The machine pulley 118 guides the traction medium 114 to move the counterweight unit 106 and the elevator car 102 in opposite directions. Herein, the machine mount 136 is adapted to accommodate the machine pulley 118. The machine mount 136 is supported on the supporting structure 138. Herein, the elevator car 102 and the counterweight unit 106 are 2:1 suspended. Such 2:1 suspension has the advantage of reducing the torque provided by the machine pulley 118.

[0072] The supporting structure 138 is positioned on the top portion of the car guide rail 104 to support the machine mount 136. Herein, the end connector 140 is coupled with the car guide rail 104 and vertically positioned below the supporting structure 138 to support one end of the traction medium 114. Further, the end connector 141

[0073]

[0074] is coupled with the car guide rail 105 to support another end of the traction medium 114.

[0075] The elevator installation 100 comprises a pair of idler car pulleys 134 connected with the machine pulley 118 via the traction medium 114. Herein, the pair of idler car pulleys 134 is positioned underneath a floor of the elevator car 102, such that the elevator car 102 is under-wrapped by the traction medium 114.

[0076] The counterweight unit 106 comprises a counterweight (not separately referenced), a supporting frame 110, a plurality of second guide shoes 111, and a pulley box 112. The supporting frame 110 comprises a first member 110-1 and a second member 110-2 parallel to the first member 110-1. Herein, the second guide shoes 111 are mounted on a top portion and a bottom portion of each of the first member 110-1 and the second member 110-2. Further, the second guide shoes 111 are engaged with at least one counterweight guide rail 108 to guide the movement of the counterweight unit 106.

[0077] The pulley box 112 is mounted on a top portion of the supporting frame 110 via a plurality of fasteners 142. The pulley box 112 comprises a plurality of first holes 144 (shown in Figure 3 A) to mount the pulley box 112 on the supporting frame 110. Herein, the supporting frame 110 comprises a plurality of second holes aligned with the plurality of first holes 144 to receive the plurality of fasteners 142 to mount the pulley box 112 on the supporting frame 110.

[0078] Constructional and operational details of the pulley box 112 are explained in the subsequent paragraphs with reference to Figures 3 A to 5.

[0079] Figure 3A illustrates a perspective view of the pulley box 112 of the counterweight unit 106 from Figure 2. Figure 3B illustrates a side view of the pulley box 112 of the counterweight unit 106 from Figure 2. Figure 3C illustrates

[0080]

[0081] a top view of the pulley box 112 of the counterweight unit 106 from Figure 2.

[0082] Figure 3D illustrates a perspective view of the pulley box 112 mounted on the counterweight unit 106 from Figure 2. Figure 4 illustrates a side view of a pulley 116 mounted on a mounting structure 122 of the pulley box 112 from Figure 3.

[0083] Figure 5 illustrates a schematic view of the elevator installation 100 from Figure 1.

[0084] The pulley box 112 comprises the at least one pulley 116, the mounting structure 122 and a dust cover 24. As shown in Figure 3A, the at least one pulley 116 comprises two pulleys 116 positioned on a top portion of the counterweight unit 106. Herein, two pulleys 116 are positioned in a parallel orientation relative to each other. In the subsequent paragraphs, two pulleys 116 are interchangeably referred to as the pulley 116, without departing from the scope of the present invention.

[0085] The pulley 116 is connected to the machine pulley 118 via the traction medium 114. Further, the machine pulley 118 is positioned on the top portion of the car guide rail 104. Herein, the machine pulley 118 is connected to the pair of idler car pulleys 134 to move the elector car 102 in the opposite direction relative to the counterweight unit 106.

[0086] Herein, the mounting structure 122 comprises a shaft 123 to support the pulley 116. The pulley 116 is rotatably mounted on the shaft of the mounting structure 122. The pulley 116 comprises a pulley rotational axis P-P’ and the pulley 116 is adapted to be rotated around the pulley rotational axis P-P’. The pulley rotational axis P-P’ is a horizontal axis of the pulley 116.

[0087] The pulley 116 is positioned on the top portion of the counterweight unit 106, such that the pulley rotational axis P-P’ of the at least one pulley 116 is parallel to a machine pulley rotational axis M-M’ (as shown in Figure 1) of the at least one machine pulley 118. Herein, the pulley rotational axis P-P’ is horizontally offset with respect to a centre of gravity of the counterweight unit 106.

[0088]

[0089] The pulley rotational axis P-P’ of the at least one pulley 116 is offset in the direction towards the elevator car 102 with respect to the centre of gravity of the counterweight unit 106. The at least one pulley 116 is offset with respect to the centre of gravity of the counterweight unit 106, such that a predefined distance is maintained between the pulley rotational axis P-P’ and the centre of gravity of the counterweight unit 106. Herein, a central horizontal axis C-C’ of the counterweight unit 106 passes through the centre of gravity of the counterweight unit 106. In an embodiment, as shown in Figure 3C, the predefined distance such as G is maintained between the pulley rotational axis P-P’ and the central horizontal axis C-C’ of the counterweight unit 106.

[0090] As shown in Figure 5, a first angle 0i is formed between the pulley vertical axis V-V’ of the pulley 116 and the traction medium 114 connected with the machine pulley 118. Further, a second angle 02 is formed between the pulley vertical axis V-V’ and the traction medium 114 connected to the end connector 140.

[0091] As explained earlier, the pulley rotational axis P-P’ of the at least one pulley 116 is offset in the direction towards the elevator car 102 with respect to the centre of gravity of the counterweight unit 106. Herein, the predefined distance is maintained between the pulley rotational axis P-P’ and the centre of gravity of the counterweight unit 106. Such arrangement of the pulley 116 reduces the first angle 0i and the second angle 02. Due to the reduction in the first angle 0i and the second angle 02, one or more forces acting on the end connector 140 are reduced when the counterweight unit 106 is in a headroom region or moving towards the headroom region. This further improves the performance and service life of the end connector 140 and the elevator installation 100.

[0092] As shown in Figures 2 and 3D, the mounting structure 122 is mounted on the supporting frame 110. The mounting structure 122 comprises a plurality of receiving holes to receive a plurality of fasteners 146 to mount the dust cover 124.

[0093]

[0094] As shown in Figure 4, the pulley box 112 comprises a bottom retainer 126, a side retainer 128, and a protection cover 130. The bottom retainer 126 is attached to the shaft 123 of the mounting structure 122 to cover at least a portion of the pulley 116. Herein, the bottom retainer 126 is attached to the shaft 123 via at least one fastener 148.

[0095] The side retainer 128 is attached to the bottom retainer 126, adjacent to the dust cover 124 via at least one fastener 150 to cover at least a portion of the pulley 116. Herein, the implementation of the bottom retainer 126 and the side retainer 128 protects or covers the pulley 116 from the bottom and a side portion, respectively. Further, the protection cover 130 is supported on the mounting structure 122 in a parallel orientation relative to the dust cover 124. The protection cover 130 is adapted to protect the pulley 116 from the external environment.

[0096] The dust cover 124 is mounted on the mounting structure 122 to cover the at least one pulley 116. In an embodiment, the dust cover 124 comprises a body 131 and at least one pair of mounting members 132-1, 132-2. The body 131 is positioned adjacent to the at least one pulley 116. The at least one pair of mounting members 132-1, 132-2 orthogonally extends from each end of the body 131. Herein, the at least one pair of mounting members 132-1, 132-2 comprises four mounting members 132-1, 132-2.

[0097] Each pair of mounting members 132-1, 132-2 comprises a first mounting member 132-1 and a second mounting member 132-2. The first mounting member 132-1 comprises a first mounting hole positioned at a first predefined distance DI from the body 131. Further, the second mounting member 132-2 is parallel to the first mounting member 132-1. The second mounting member 132-2 comprises a second mounting hole positioned at a second predefined distance D2 from the body 131.

[0098]

[0099] Herein, the second predefined distance D2 is greater than the first predefined distance DI to ensure the proper mounting of the dust cover 124 on the mounting structure 122. Each of the first mounting hole and the second mounting hole of the dust cover 124 is aligned with a respective receiving hole of the mounting structure 122 to mount the dust cover 124.

[0100] Thus, the difference in the second predefined distance D2 and the predefined distance DI ensures that the first mounting hole and the second mounting hole can be aligned only with the respective receiving hole of the mounting structure 122 to mount the dust cover 124. Herein, the implementation of the first mounting hole and the second mounting hole located at different distances, such as DI and D2, ensures that the dust cover 124 is mounted on the mounting structure 122 in a specific orientation and at a desired position on the mounting structure 122. Further, the dust cover 124 is mounted on the mounting structure 122 via the plurality of fasteners 146.

Claims

Claims:

1. An elevator installation (100), comprising:a counterweight unit (106) having a supporting frame (110) and a pulley box (112) mounted on the supporting frame (110); andan elevator car (102) coupled to the counterweight unit (106) via a traction medium (114) and guided by at least one car guide rail (104) to move within an elevator shaft;at least one machine pulley (118) positioned on a top portion of the at least one car guide rail (104) of the elevator installation (100) and guiding the traction medium (114) to move the counterweight unit (106) and the elevator car (102) in opposite directions;wherein:the pulley box (112) comprises at least one pulley (116) positioned on a top portion of the counterweight unit (106) and connected with the at least one machine pulley (118) via the traction medium (114),wherein a pulley rotational axis (P-P’) of the at least one pulley (116) is parallel to a machine pulley rotational axis (M-M’) of the at least one machine pulley (118),characterized in that the pulley rotational axis (P-P’) is horizontally offset with respect to a centre of gravity of the counterweight unit (106).

2. The elevator installation (100) according to claim 1, wherein the pulley rotational axis (P-P’) of the at least one pulley (116) is horizontally offset with respect to the centre of gravity of the counterweight unit (106) in the direction towards the elevator car (102).

3. The elevator installation (100) according to any one of the preceding claims, wherein the at least one pulley (116) is offset with respect to the centre of gravity of the counterweight unit (106), such that a predefined distance ismaintained between the pulley rotational axis (P-P’) and the centre of gravity of the counterweight unit (106).

4. The elevator installation (100) according to any one of the preceding claims, comprising a pair of idler car pulleys (134) connected with the at least one machine pulley (118) via the traction medium (114) and positioned underneath a floor of the elevator car (102), such that the elevator car (102) is under-wrapped by the traction medium (114).

5. The elevator installation (100) according to any one of the preceding claims, wherein the elevator car (102) and the counterweight unit (106) are 2:1- suspended.

6. The elevator installation (100) according to any one of the preceding claims, comprising:a machine mount (136) adapted to accommodate or accommodating the machine pulley (118);a supporting structure (138) positioned on the top portion of the at least one car guide rail (104) to support the machine mount (136); andan end connector (140) coupled with the at least one car guide rail (104) and vertically positioned below the supporting structure (138).

7. The elevator installation (100) according to any one of the preceding claims, wherein the pulley box (112) comprises:a mounting structure (122) mounted on the supporting frame (110); and a dust cover (124) mounted on the mounting structure (122) to cover the at least one pulley (116).

8. The elevator installation (100) according to claim 7, wherein the mounting structure (122) comprises a plurality of receiving holes to mount the dust cover (124), such that each of a first mounting hole and a second mountinghole of the dust cover (124) is aligned with a respective receiving hole of the mounting structure (122) to mount the dust cover (124).

9. The elevator installation (100) according to any one of claim 7 or 8, wherein:the mounting structure (122) comprises a shaft (123) to support the at least one pulley (116), andthe at least one pulley (116) is rotatably mounted on the shaft of the mounting structure (122).

10. The elevator installation (100) according to claim 9, wherein the pulley box (112) comprises a bottom retainer (126) attached to the shaft (123) of the mounting structure (122) to cover at least a portion of the at least one pulley (H6).

11. The elevator installation (100) according to claim 10, wherein the pulley box (112) comprises a side retainer (128) attached to the bottom retainer (126), adjacent to the dust cover (124), to cover at least a portion of the at least one pulley (116).

12. The elevator installation (100) according to any one of claims 7 to 11, wherein the pulley box (112) comprises a protection cover (130) supported on the mounting structure (122) in a parallel orientation relative to the dust cover (124).

13. The elevator installation (100) according to any one of claims 7 to 12, wherein the dust cover (124) comprises:a body (131) positioned adjacent to the at least one pulley (116); and at least one pair of mounting members (132-1, 132-2) orthogonally extending from each end of the body (131) and comprising:a first mounting member (132-1) having a first mounting hole positioned at a first predefined distance (DI) from the body (131); and19a second mounting member (132-2) parallel to the first mounting member (132-1) and having a second mounting hole positioned at a second predefined distance (D2) from the body (131),wherein the second predefined distance (D2) is greater than the first predefined distance (DI).

14. A counterweight unit (106) for an elevator installation (100), the counterweight unit (106) comprising:a supporting frame (110); anda pulley box (112) mounted on the supporting frame (110), the pulley box (112) comprising:at least one pulley (116) positioned on a top portion of the counterweight unit (106) and adapted to be connected with at least one machine pulley (118) via a traction medium (114) of the elevator installation (100),wherein the counterweight unit (106) is configured to be arranged such that in an operational configuration of the elevator installation (100) a pulley rotational axis (P-P’) of the at least one pulley (116) is parallel to a machine pulley rotational axis (M-M’) of the at least one machine pulley (118), and wherein the pulley rotational axis (P-P’) is horizontally offset with respect to a centre of gravity of the counterweight unit (106).20

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