A belt tensioning system

Abstract

A belt tensioning system (170) for tensioning a belt (171) of a belt drive system (970), wherein the belt drive system (970) is used to transmit torque from a drive unit (112) of a door operating system (100) to a sliding door leaf (101) of a sliding door assembly (200), the belt tensioning system comprising: a pulley (176), the pulley (176) being connectable to a belt (171), the belt (171) being used to transmit torque between the pulley (176) of the belt drive system (970) and an additional pulley (175); a pulley guide (330), the pulley (176) being movably connected to the pulley guide (330); and a belt tensioning device (470), which is operably connected to the pulley (176) and the pulley guide (330) and is used to adjust the position of the pulley (176) relative to the pulley guide (330).

Description

Technical Field

[0001] The present invention relates to a belt tensioning system, a belt driving system comprising the belt tensioning system, a door operating system comprising the belt driving system, and a sliding door assembly comprising the door operating system. Background Art

[0002] It is generally known to use sliding doors that automatically open and close to facilitate access to buildings, rooms, and other areas. Conventional sliding doors are driven by a drive unit mounted on the door frame, which drives a trolley along a track via a drive belt. The trolley is in turn attached to the sliding door leaf, which is then driven by the drive unit.

[0003] The drive belt must be kept under high tension at all times, as a loss of belt tension results in a loss of efficiency, or in the worst case, a complete inability to transmit torque through the drive belt.

[0004] Belt tension is closely related to temperature because the belt and the supporting structure on which the driven pulley is mounted have different temperature expansion characteristics. Therefore, temperature changes will quickly cause a loss of belt tension.

[0005] To allow maintenance personnel to adjust the belt tension, sliding door systems are typically equipped with a spring-loaded tensioning bolt that is tightened to the level indicated on the tensioning pulley assembly. However, tensioning is time-consuming and requires trained personnel to achieve the correct tension in a safe manner.

[0006] The inventors have recognized that improvements are needed in this area. Summary of the Invention

[0007] Therefore, the purpose of the present invention is to provide a solution to the above problems and to reduce the disadvantages of the prior art solutions.

[0008] According to one aspect, a belt tensioning system is provided for tensioning a belt drive system for transmitting a transmission from a drive unit of a door operating system to a sliding door leaf of a sliding door assembly.

[0009] The belt tensioning system comprises a pulley and a pulley guide, wherein the pulley is connectable to a belt for transmitting torque between the pulley and an additional pulley of the belt drive system. The pulley is movably connected to the pulley guide.

[0010] The belt tensioning system further includes a belt tensioning device operatively connected to the pulley and the pulley guide for adjusting a position of the pulley relative to the pulley guide.

[0011] The belt tensioning device includes an engaging member and a tensioning member. The engaging member includes an eccentric cam structure, and the tensioning member is arranged to engage the eccentric cam structure of the tensioning member. The engaging member and the tensioning member are adjustable relative to each other to adjust the position of the pulley relative to the pulley guide.

[0012] According to one aspect, a belt drive system is provided. The belt drive system comprises the belt tensioning system according to the above, a belt, and an additional pulley. The pulley is connected to the additional pulley via a belt.

[0013] According to one aspect, a door operating system is provided, comprising a drive unit and the belt drive system for transmitting torque from the drive unit to a sliding door of a sliding door assembly.

[0014] According to one aspect, a sliding door assembly is provided, comprising at least one sliding door leaf and a door operating system according to the above method suitable for operating the at least one sliding door leaf. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the following, embodiments of the present invention will be described with reference to the accompanying drawings; the drawings show non-limiting examples of how the inventive concept may be implemented.

[0016] Figure 1 is a front view of a sliding door assembly according to one embodiment.

[0017] Figure 2 is a front view of a belt tensioning system according to one embodiment.

[0018] Figure 3 is a cross-sectional view of a portion of a belt tensioning system according to one embodiment.

[0019] Figure 4 is a top view of a belt tensioning system according to one embodiment. DETAILED DESCRIPTION

[0020] Examples of the door operating system 100 and the sliding door assembly 200 will be described below. Figure 1 The sliding door assembly includes a sliding door leaf 101, a sliding door track 110, and a door operating system 100 for operating the sliding door leaf 101. The door operating system 100 includes a drive unit 112 for driving the sliding door leaf 101. The sliding door leaf 101 is driven by the drive unit 112 along the sliding door track 110 fixed relative to the door frame 102.

[0021] The sliding door leaf 101 is slidingly connected to the sliding door track 110, for example, by at least one trolley 130. The trolley 130 preferably engages the sliding door track 110 via at least one low friction wheel, allowing the sliding door leaf 101 to move along the horizontal sliding door track 110 to closed and open positions.

[0022] Further references Figure 1 The door operating system 100 can include a drive unit 112, which can be of any conventional type. Typically, the drive unit 112 comprises an electric motor and a reduction gearing that provides the necessary torque to move the sliding door leaf 101 between the open and closed positions. In this example, a belt drive connects the drive unit 112 to the trolley 130, with the drive unit 112 serving as the drive member. Advantageously, the drive unit 112 is adapted to be connected to the door frame 102 of the sliding door assembly, or even mounted internally in the upper portion of the door frame 102. Thus, the door operating system 100 can be mounted to the support structure 99 of the sliding door assembly 200.

[0023] Door operating system 100 may include a belt drive system 970. The belt drive system includes pulley 176, an additional pulley 175, and a belt 171. Belt 171 connects pulley 176 and additional pulley 175 to transmit torque between the pulleys 176 and the additional pulley 175. Belt drive system 970 is configured to be driven by drive unit 112. Pulley 176 may be defined as a first pulley, while additional pulley 175 may be defined as a second pulley 175.

[0024] The trolley 130 is connected to a belt 171 which is used to transfer torque from the belt drive system 970 to the sliding door leaf 101. Thus, the belt 171 is configured to be mounted to the sliding door leaf 101.

[0025] Belt 171 is preferably a synchronous, endless drive belt extending between pulley 176 and an additional pulley 175. In one embodiment, additional pulley 175 is directly driven by drive unit 112, and another pulley 176 is rotatably supported by console 108, which is fixed to door frame 102. Pulley 176 and additional pulley 175 may be toothed wheels. Thus, drive belt 171 may be a toothed belt.

[0026] Typically, the door frame 102 includes a support structure 99. The support structure 99 can be a header. The header can extend above the sliding door leaf 101. The belt tensioning system 170 and the door operating system 100 can be mounted to the header 99.

[0027] Thus, pulley 176 and additional pulley 175 are rotatably coupled to header 99. In most cases, header 99 and belt 171 are made of different materials. For example, header 99 may be aluminum, while belt 171 is typically made of at least steel, i.e., steel reinforcement. Therefore, if the sliding door assembly experiences temperature fluctuations, the difference in thermal expansion characteristics between header 99 and belt 171 will cause belt 171 tension to relax due to the different expansion of header 99 and belt 171.

[0028] According to the present invention, this can be solved by including a pulley 176 in the belt tensioning system, which will be referred to as Figures 2 to 4 Further description.

[0029] Figure 2 Depicts the reference for tensioning Figure 1 A front view of a belt tensioning system 170 of a belt 171 of a belt drive system is depicted.

[0030] The belt tensioning system 170 includes a pulley 176. The pulley 176 can be connected to the reference Figure 1 A belt drive system is described with a belt and attached pulleys.

[0031] The belt tensioning system 170 includes a pulley guide 330. The pulley 176 is movably connected to the pulley guide 330. Therefore, the pulley guide 330 is arranged to accommodate positional adjustment of the pulley 176 relative to the pulley guide 330. In other words, the pulley guide 330 is arranged to accommodate adjustment of the pulley 176 relative to the additional pulley 175.

[0032] In addition, the belt tensioning system 170 includes a belt tensioning device 470 for adjusting the position of the pulley 176 relative to the pulley guide 330 (and the additional pulley 175). The belt tensioning device 470 is operatively connected to the pulley 176 and the pulley guide 330. Therefore, the belt tensioning device 470 is arranged between the pulley 176 and the pulley guide 330.

[0033] The belt tensioning device comprises an engaging member 340 and a tensioning member 370. The engaging member 340 comprises an eccentric cam structure 341. The tensioning member 370 is arranged to engage the eccentric cam structure 341 of the engaging member 340. Therefore, the tensioning member 370 is arranged to contact the eccentric cam structure 341.

[0034] The engagement member 340 and the tensioning member 370 are adjustable relative to each other to adjust the position of the pulley 176 relative to the pulley guide 330. Thus, the point of engagement between the engagement member 340 and the tensioning member 370 on the eccentric cam structure 341 is adjustable such that relative adjustment of the tensioning member 370 and the engagement member 340 results in adjustment of the position of the pulley 176 relative to the pulley guide 330. Thus, the engagement member 340 and the tensioning member 370 can be selectively moved relative to each other.

[0035] Thus, the belt tensioning system according to the above can be operated in a user-friendly manner simply by adjusting the belt tensioning device, compared to conventional belt tensioning systems, in which the user must use specific tools and follow difficult-to-interpret scales in order to set the correct tension through the incremental turning of multiple adjustment screws. The tensioning system according to the present invention can simplify this process by implementing a suitable eccentric cam structure to guide the user to the correct tension.

[0036] Because the tensioning member engages the eccentric cam structure 341, belt 171 can be tensioned by rotating the engagement member 340. Rotation of the engagement member 340 causes pulley 176 to move relative to the pulley guide 330. Thus, rotation of the engagement member 340 allows the engagement member 340 to be adjustable relative to the tensioning member 370. In one embodiment, the eccentric cam structure 341 is formed by an eccentric disk 347. In one embodiment, rotation of the eccentric disk 347 allows the engagement member 340 to be adjustable relative to the tensioning member 370.

[0037] As will be appreciated by those skilled in the art, the positioning of the engagement member and the tensioning member can be varied. In one embodiment, the engagement member 340 is operably connected to the pulley 176, and the tensioning member 370 is operably connected to the pulley guide 330. Thus, the engagement member 340 can be mounted to the pulley 176. The pulley 176 can rotate relative to the engagement member 340. This makes using the belt tensioning system less complex and more intuitive. However, in alternative embodiments, the tensioning member 370 can be operably connected to the pulley 176, while the engagement member is operably connected to the pulley guide 330.

[0038] The belt tensioning system 170 may include a mounting portion 320. The mounting portion 320 is arranged to be mounted to the support structure 99 (e.g., Figure 1 ). The mounting portion 320 may be arranged to be mounted to a support structure by means of fastening elements 321 .

[0039] The pulley guide 330 is fixed relative to the support structure of the sliding door assembly. The pulley guide 330 can be connected to (e.g., fixed to) the mounting portion 320. Therefore, the pulley guide 330 can be arranged to be mounted to the support structure 99 via the mounting portion 320.

[0040] The pulley guide 330 is arranged to allow the pulley 176 to move along the tensioning axis A. The tensioning axis A extends parallel to the belt.

[0041] In one embodiment, the belt tensioning system includes a first plate member 373 . The first plate member is connected to the mounting portion 320 . The first plate member 373 extends along the tensioning axis A. The first plate member 373 may include a pulley guide 330 .

[0042] In one embodiment, the belt tensioning system 170 may further include a securing member 310. The securing member 310 is adapted to releasably secure the position of the pulley 176 relative to the pulley guide 330. Thus, once the position of the pulley 176 is adjusted, the pulley 176 may be secured in the adjusted position relative to the pulley guide 330. To allow adjustment, the securing member may be released. Releasable in this context may refer to disengageable, i.e., arranged to be in an engaged position and a disengaged position.

[0043] The securing member 310 can be arranged to releasably secure the engagement member 340 relative to the tensioning member 370. Thus, securing the position of the engagement member and securing the position of the pulley can be performed in one operation, thereby making the belt tensioning system more user-friendly and time-efficient. In one embodiment, the securing member 310 can be arranged to releasably secure the engagement member 340 to the pulley guide 330.

[0044] Will refer to it later Figure 3 The fixing member 310 is further described.

[0045] Further references Figure 2 , tensioning member 370 can be biased against engagement member 340. This ensures that engagement between the engagement member and the tensioning member is maintained. Furthermore, it allows for adjustment of the tension in the belt without having to manually position the tensioning member relative to the engagement member each time. Thus, tensioning member 370 is adjustable relative to engagement member 340, at least by being biased against said engagement member 340.

[0046] In this context, biased means that the tensioning member 370 is spring loaded to apply a contact force to the eccentric cam structure 341 of the engagement member 340 .

[0047] The tensioning member 370 may include a tensioning element 375. The tensioning element 375 may be an elongated element, such as a screw.

[0048] The first end 376 of the tensioning element may be arranged to engage the engagement member 340 .

[0049] The belt tensioning system 170 may further include a tensioning guide 390. The tensioning guide 390 is adapted to guide movement of the tensioning element 375 relative to the engagement member 340.

[0050] The tensioning guide may be fixed relative to the mounting portion 320. In an alternative embodiment, the tensioning guide may be arranged to be fixed directly to a support structure of the sliding door assembly.

[0051] In one embodiment, the tensioning element 375 can be connected to the tensioning guide 390 by means of a spring 374. The spring 374 is arranged to bias the tensioning element 375 against the engagement member 340. A first end of the spring 374 can be connected to a first end 376 of the tensioning element 375. A second end of the spring 374 can be connected to the tensioning guide 390.

[0052] The tensioning element 375 can extend along a tensioning axis A. The tensioning element 375 can move along the tensioning axis A. The spring 374 can be coaxial with the tensioning element 375. The tensioning axis A can be aligned with the eccentric cam structure 341 of the engagement member 340 so that the tensioning element 375 engages the eccentric cam structure 341. Thus, the eccentric outer surface of the eccentric cam structure 341 can extend orthogonally to the tensioning axis A.

[0053] The tensioning element 375 may include a second end 377. The second end 377 is opposite the first end 376. The second end 377 may be guided by a tensioning guide 390. The second end 377 may be a free end of the tensioning element 375.

[0054] like Figure 1 As shown, the belt tensioning system 170 may further include a tension indicating device 410. The tension indicating device 410 is intended to provide an indication to the user regarding the tension of the belt.

[0055] Thus, the tension indicating device 410 is arranged to indicate at least one predetermined position of the reference point 414 of the tensioning element 375 relative to the engagement member 340. Each of the at least one predetermined position is associated with a respective position of the pulley 176 relative to the pulley guide 330.

[0056] The reference point can be second end 377 or any selected point along tensioning element 375. By using the tension indicator, maintenance personnel are directly informed of the appropriate pulley position. This appropriate position can be selected to accommodate varying belt tensions. Thus, maintenance personnel can adjust the engaging member and the tensioning member based on the predetermined position of the tensioning element's reference point, as indicated by the tension indicator.

[0057] The tensioning indicating means may comprise a set of indicators at predetermined positions along the tensioning axis A. The set of indicators may comprise a scale with markings 411 , 412 , 413 indicating the predetermined positions.

[0058] The tension indicator device may be positioned proximate to the tensioning element 375. In one embodiment, the tension indicator device is positioned on the tensioning guide 390 or the mounting portion 320. However, preferably, the tension indicator device 410 is positioned on the first plate element 373, preferably proximate to the tensioning member 370.

[0059] The tensioning member 370 may include an adjustment element 379 adapted to adjust the bias of the tensioning member 370, i.e., the tension of the spring 374. Thus, the force with which the tensioning member engages the engagement member can be adjusted by means of the adjustment element. This makes the belt tensioning system more robust and reliable, being less susceptible to wear or failure due to disengagement of the engagement member and the tensioning member.

[0060] The adjustment element 379 may be disposed adjacent an adjustment flange 391 of the tensioning guide. The adjustment flange 391 includes a hole for movably receiving the tensioning element 375.

[0061] In one embodiment, spring 374 is mounted to adjustment flange 391 and first end 376 of tensioning member 375. In one embodiment, tensioning member 375 includes a threaded portion, wherein adjustment member 379 is mounted to the threaded portion for adjusting the tension of spring 374 relative to adjustment flange 391. Adjustment member 379 can be a nut.

[0062] The tensioning element 375 may include a head. The first end 376 may be the head. The head may protrude radially from the tensioning axis A relative to the middle portion of the tensioning element 375 to prevent the first end from passing through the hole of the adjustment flange 391.

[0063] In one embodiment, the tensioning guide 390 can include a stop flange 392. The stop flange 392 can include a hole for movably receiving the tensioning element 375. The stop flange 392 is arranged along the tensioning axis A away from the engagement member 340 relative to the adjustment flange 391. The tensioning member 370 can include a stop element 378. The stop element 378 can protrude radially from the tensioning axis A relative to the tensioning element 375 to prevent the tensioning element 375 from passing through the hole of the stop flange 392 beyond the stop element 378.

[0064] In one embodiment, a stop member 378 is mounted to a threaded portion of the tensioning member 375 for adjusting a position of the stop member 378 relative to the tensioning member 375 along the tensioning axis A. The stop member 378 may be a nut.

[0065] In one embodiment, the first plate element 373 may comprise a tensioning guide 390. The stop flange 392 and / or the adjustment flange 391 may respectively form a protruding portion of the first plate element 373.

[0066] Thus, the tensioning member 370 is movably connected to the first plate element 373. Furthermore, the pulley 176 may be rotatably and movably connected to the first plate element 373 by means of a pulley guide 330.

[0067] like Figure 2 As shown, the pulley guide 330 includes an elongated recess 331 for receiving a guide member connected to the pulley 176 for guiding the pulley 176. The elongated recess can extend along the tensioning axis A. Therefore, the guide member can extend orthogonally to the tensioning axis A and pass through the elongated recess 331. Therefore, the pulley 176 is movably connected to the elongated recess 331 via the guide member. The first plate element 373 can include the pulley guide and the elongated recess 331.

[0068] Those skilled in the art recognize that the pulley guides 330 may be arranged in different ways to allow the motion of the pulley 176 to be guided. In an alternative embodiment, the pulley 176 may be mounted to a movable console that is slidably connected to a track forming the pulley guides.

[0069] Go to Figure 3 , depicts a cross-sectional view of a portion of the belt tensioning system. Pulley 176 is rotatable about a pulley axis B. Pulley axis B is orthogonal to the reference Figure 1 The tensioning axis A is described to extend.

[0070] As described Figure 3 As seen in FIG, the fixing member 310 includes a fixing element 311, such as a threaded member. The fixing element 311 can be rotatably coupled to the pulley 176. The fixing element 311 can extend through the pulley guide 330 and the engaging member 340. When the fixing element 311 is tightened, the engaging member 340 is locked in place, and the position of the pulley 176 is fixed relative to the pulley guide 330. When the fixing element 311 is loosened, the engaging member can rotate relative to the fixing element 311, and the pulley 176 can move relative to the pulley guide 330.

[0071] This makes tensioning uncomplicated, since the fixing element allows fixing or achieving the positioning of both the pulley and the engaging member with just one action.

[0072] The fixing element 311 may constitute a guide member which is guided in the elongated recess 331. Thus, the elongated recess 331 may be adapted to receive a portion of the fixing element 311 for guiding the belt pulley 176.

[0073] Thus, the engagement member 340 may include a through hole for receiving the fixing element 311. The through hole may be aligned with the pulley axis B.

[0074] The fixed element 311 can extend along the pulley axis B. The fixed element 311 can be rotatably coupled to the pulley 176 via a bearing 421 that includes a bearing mount 420 adapted to receive the fixed element 311. The fixed element 311 is fixedly connected to the bearing mount, and the bearing 421 is adapted to allow relative rotation between the fixed element 311 and the pulley 176.

[0075] The fixing member 311 can extend through the first plate member 373 by extending through the elongated recess 331 of the pulley guide 330 of the first plate member 373. Thus, the fixing of the fixing member 310 fixes the engagement member 340 to the first plate member 373 and fixes the position of the pulley 176 relative to the first plate member 373.

[0076] In one embodiment, the belt tensioning system may further include a spacer element 423 disposed between the engagement member 340 and the first plate element 373 along the pulley axis B. This ensures proper alignment between the tensioning member and the engagement member. The fixing element 311 may extend through the spacer element 423. The spacer element 423 may be an annular spacer element.

[0077] refer to Figure 4 , shows a top view of the belt tensioning system. The belt tensioning system 170 may also include a retaining heel 328. The retaining heel 328 may protrude from the mounting portion 320. The retaining heel 328 is arranged to engage a corresponding surface of the sliding door assembly 200. This allows for a more stable installation of the belt tensioning system.

[0078] The belt tensioning system can further include a second plate member 327. The second plate member 327 can interconnect the first plate member 373 and the mounting portion 320. The second plate member 327 can extend along the tensioning axis A.

[0079] In one embodiment, the second plate element 327 can be orthogonal to the first plate element 373 and the mounting portion 320. The mounting portion 320 and the first plate element 373 can be parallel. Preferably, the mounting portion 320 and the first plate element 373 are arranged parallel to at least one sliding door leaf of the sliding door assembly.

[0080] In one embodiment, the first and second plate members and the mounting portion may be made of aluminum.

[0081] According to one aspect, a belt drive system 970 is provided. The belt drive system 970 comprises a belt tensioning system 170 according to any of the previous embodiments, a belt 171 and an additional pulley 175. The pulley 176 of the belt tensioning system 170 is connected to the additional pulley 175 via the belt 171.

[0082] According to one aspect, a door operating system 100 is provided. The door operating system 100 includes a drive unit 112 and a belt drive system 970 for transmitting torque from the drive unit 112 of the door operating system 100 to a sliding door leaf 101 of a sliding door assembly 200 .

[0083] According to one aspect, a sliding door assembly 200 is provided. The sliding door assembly comprises at least one sliding door leaf 101 and a door operating system 100. The door operating system is adapted to operate the at least one sliding door leaf 101.

[0084] According to one aspect, a method for adjusting belt tension in a belt drive system 970 according to the above is provided. The method includes adjusting engagement member 340 and tensioning member 370 relative to each other to adjust the position of pulley 176 relative to pulley guide 330.

[0085] The method may further include fixing the position of the pulley 176 relative to the pulley guide 330 via the fixing member 310 .

[0086] The method may further include securing the engagement member 340 relative to the tensioning member 370 by means of the securing member 310 .

[0087] It will be understood that although many features and advantages of the invention and details of its structure and function have been set forth in the foregoing description, this description is illustrative only and that changes may be made in detail, particularly in the shape, size and arrangement of parts within the scope of the invention as indicated by the appended claims.

Claims

1. A belt tensioning system (170) for tensioning a belt (171) of a belt drive system (970), wherein the belt drive system (970) is used to transmit torque from a drive unit (112) of a door operating system (100) to a sliding door leaf (101) of a sliding door assembly (200), the belt tensioning system comprising: a pulley (176) connectable to the belt (171), the belt (171) being used to transmit torque between the pulley (176) and an additional pulley (175) of the belt drive system (970); a pulley guide (330) to which the pulley (176) is movably connected; and a belt tensioning device (470) operatively connected to the pulley (176) and the pulley guide (330) for adjusting the position of the pulley (176) relative to the pulley guide (330), The belt tensioning device (470) includes a coupling member (340) and a tensioning member (370), wherein the coupling member (340) includes an eccentric cam structure (341), and the tensioning member (370) is arranged to engage the eccentric cam structure (341) of the coupling member (340), and the coupling member (340) and the tensioning member (370) are capable of adjusting relative to each other to adjust the position of the pulley (176) relative to the pulley guide device (330).

2. The belt tensioning system (170) according to claim 1, wherein: The engaging member (340) is mounted to the pulley (176), and the pulley (176) is rotatable relative to the engaging member (340).

3. The belt tensioning system (170) of claim 1, further comprising a securing member (310) adapted to releasably secure a position of the pulley (176) relative to the pulley guide (330).

4. The belt tensioning system (170) according to claim 3, wherein: The securing member (310) is arranged to releasably secure the engagement member (340) relative to the tensioning member (370).

5. The belt tensioning system (170) of claim 3, wherein: The fixing member (310) includes a fixing element (311) rotatably coupled to the pulley (176), the fixing element (311) extending through the pulley guide (330) and the engaging member (340).

6. The belt tensioning system (170) according to claim 5, wherein: The pulley guide (330) comprises an elongated recess (331) adapted to receive a portion of the fixing element (311) for guiding the pulley (176).

7. The belt tensioning system (170) according to any one of claims 1 to 6, wherein: The tensioning member (370) is biased against the engagement member (340).

8. The belt tensioning system (170) according to any one of claims 1 to 6, wherein: The tensioning member (370) comprises a tensioning element (375), wherein a first end (376) of the tensioning element (375) is arranged to engage the engagement member (340).

9. The belt tensioning system (170) of claim 8, further comprising a tensioning guide (390) adapted to guide movement of the tensioning element (375) relative to the engagement member (340).

10. The belt tensioning system (170) according to claim 9, further comprising a tensioning indication device (410), wherein the tensioning indication device (410) is arranged to indicate at least one predetermined position of a reference point (414) of the tensioning element (375) relative to the engaging member (340), each of the at least one predetermined position being associated with a respective position of the pulley (176) relative to the pulley guide device (330).

11. The belt tensioning system (170) according to any one of claims 1 to 6, further comprising a mounting portion (320) arranged to be mounted to a support structure (99) of the sliding door assembly (200).

12. The belt tensioning system (170) of claim 11, further comprising a retaining heel (328) protruding from the mounting portion (320), the retaining heel (328) being arranged to engage a corresponding surface of the support structure (99) of the sliding door assembly (200).

13. The belt tensioning system (170) according to any one of claims 1 to 6, wherein: The eccentric cam structure (341) comprises an eccentric disc (347), wherein the engagement member (340) is adjustable relative to the tensioning member (370) by means of rotation of the eccentric disc (347).

14. A belt drive system (970) comprising a belt tensioning system (170) according to any one of claims 1 to 13, a belt (171) and an additional pulley (175), wherein: The pulley (176) of the belt tensioning system (170) is connected to the additional pulley (175) via the belt (171).

15. A door operating system (100) comprising a drive unit (112) and a belt drive system (970) according to claim 14, wherein the belt drive system (970) is used to transmit torque from the drive unit (112) to a sliding door leaf (101) of the sliding door assembly (200).

16. A sliding door assembly (200) comprising at least one sliding door leaf (101) and a door operating system (100) according to claim 15, wherein the door operating system is suitable for operating the at least one sliding door leaf (101).

17. A method for adjusting the tension of the belt in the belt drive system (970) of claim 14, the method comprising adjusting the engagement member (340) and the tensioning member (370) relative to each other to adjust the position of the pulley (176) relative to the pulley guide (330).

18. The method of claim 17, further comprising fixing a position of the pulley (176) relative to the pulley guide (330) via a fixing member (310).

19. The method of claim 18, further comprising securing the engagement member (340) relative to the tensioning member (370) by means of the securing member (310).

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