The present invention relates to a passenger conveyor comprising a conveyor surface as well as a handrail system comprising a handrail belt driven by handrail drive. In these types of passenger conveyors according to the invention the handrail belt is normally running between heads of the conveyor which are located at both ends of the passenger conveyor. In the heads of the passenger conveyor the direction of the handrail belt is changed between an upper track where the handrail belt is to be gripped by passengers and a lower return path which is usually invisible for the passengers in which the handrail belt is transferred upside-down back to the other conveyor head. Such inventive passenger conveyors are usually escalators or travelators.

The handrail belt of the invention is driven by a handrail drive which often comprises a handrail drive belt. The handrail drive belt runs over a certain distance along together with the handrail belt to transfer the drive force via friction or interconnection, i.e. toothed belt, to the handrail belt.

In these known passenger conveyors one head usually comprises the drive wheel or the drive end for the handrail belt whereas the other head is normally designed as tension head which is adjustably fixed to a conveyor support structure. This tension head is adjusted to keep the handrail belt under a desired tension between the two heads of the passenger conveyor. Such a device is shown in WO 2007/ 138156. The disadvantage of this solution is that the provision of an adjustable tension head requires a certain effort with regard to the adjustments, fixtures and structural reinforcements so that the complete structure at the tension head of the passenger conveyor becomes more complicated and has to be regularly adjusted with each maintenance cycle to keep the handrail belt at the desired tension.

The GB 2 205 803 shows a passenger conveyor wherein the tensioning function is shifted from the tension head to a tensioning device provided between the heads of the passenger conveyor. By this means the heads of the passenger conveyor can be fixedly arranged and therefore require less structural effort and no adjustable rigid supports which are usually required for the adjustable support of components carrying a heavy load.

It is object of the present invention to provide a passenger conveyor with a handrail system comprising a handrail belt and a handrail drive which is able to keep the handrail belt under a desired tension and additionally provides a better travel comfort.

According to the invention this object is solved with a passenger conveyor according to claim 1. Preferred embodiments of the invention are subject matter of the sub-claims. In a passenger conveyor of the invention the tensioning device for the handrail belt is provided between the heads of the passenger conveyor, which tensioning device comprises a - preferably curved - tension guide portion and a force applying device which applies a tensioning force to the tension guide portion. The force is preferably applied perpendicular to the plane of the handrail belt, which plane of the handrail belt is defined by the planar middle portion of the handrail belt between the two rounded side portions.

The bending of the handrail and subsequently also the wear of the handrail is reduced by providing a counter guide portion on at least one preferably both sides of the tension guide portion. According to the invention one counter guide portions is a handrail drive wheel provided in one head (the drive head) of the passenger conveyor. The advantage of this arrangement is that the tensioning device is directly adjacent the handrail drive wheel in the drive head of the passenger conveyor and is therefore located well accessible so that maintenance work or adjustments can be performed easily. On the other hand the additional structures to be added to an existing device are reduced as only the tension guide portion and one of the counter portions need to be added adjacent the handrail drive wheel. The third advantage is that by providing a handrail drive wheel as one counter guide portion the handrail belt is kept longer in contact with the handrail drive wheel which again increases the friction between the handrail drive belt running around the handrail drive wheel and the handrail belt which improves the drive conditions of the handrail drive in total as a better friction means a better and more reliable drive of the handrail belt as the force transfer between the handrail drive and the handrail belt is improved.

If the tensioning device for the handrail belt is provided adjacent to the handrail drive wheel and the handrail drive wheel is used as counter guide portion of the tensioning device preferably the friction section for the handrail belt and the handrail drive belt running between the handrail belt and the handrail drive wheel is extended from the normal 180° sector M by a further sector m of 5 to 25, particularly 10 - 20°. This angle is sufficient to provide an adapted counter guide portion for the tension guide portion of the tensioning device and on the other hand leads to a better engagement between the handrail drive belt and the handrail belt which improves the travel comfort of the passenger conveyor in total. A further advantage of the invention is that the design of the conveyor is independent of its running direction.

An essential advantage of the invention is the fact that by arranging the tensioning device in connection with the drive wheel, which tensioning device uses the drive wheel as a counter guide portion an enlarged traction surface is provided at the drive wheel. This enlarged traction surface reduces the need for a high tension of the handrail belt for slip avoiding purposes. This has the effect that the construction can be generally built more compact and lightweight.

By this means of the counter guide portions which are provided at one end, preferably on both ends of the tension guide portion the tensioning force is applied to a limited area of the handrail belt. The counter guide portions are forming a counter bearing to the tension guide portion so that all the tensioning forces act on the handrail belt within the complete section of the tensioning device, i.e. the tension guide portion and the two counter guide portions on both sides thereof. The counter guide portions can also be formed by sliding tracks or rollers. They are advantageously provided with a curvature which is opposite to the curvature in the tension guide portion so as to enable a smooth transition of the handrail belt from the counter guide portions to the tensioning portion and vice versa. This adaptation of the curvatures in the different portions of the tensioning device reduces bending stress of the handrail belt and leads to a longer lifetime thereof.

The tension guide portion is provided in the return path of the handrail belt where it is usually not visible to the passengers. The tension guide portion has the advantage that by providing the force applying device in connection with the tension guide portion the bending of the handrail in that tensioning device is as low as possible which has a positive influence to the life time and wearing of the handrail belt. This reduction of bending of the handrail belt is further improved by using a curved tension guide portion. Further, no adjustable tension head has to be provided in the conveyor which essentially reduces the costs of the complete conveyor structure.

The tension guide portion could for example be provided as a sliding track on which the handrail belt is supported or as a wheel which supports the handrail belt on its circumference. The tension guide portion could also comprise a number of rollers which support the handrail belt in the tension guide portion so that the friction between the tension guide portion and the handrail belt is minimized. As force applying device which acts at least to a part of the tension guide portion, probably to the complete tension guide portion a spring could be used or any kind of hydraulic of pneumatic for supplying devices which are per se known and which are able to provide a desired force on that tension guide portion perpendicular to the run of the handrail belt and perpendicular to the gripping surface of the handrail belt. The tension guide portion can also be the circumference of one larger roller provided in the handrail casing of the passenger conveyor, which reduces friction between the tensioning device and the running handrail belt (as also a plurality of smaller rollers in the tensioning and counter guide portions do).

Preferably the curvature of the tension guide portion is opposite to the curvature of the handrail belt in the heads of the passenger conveyor. By this means it is insured that the handrail belt is pushed in a direction vertically to the top, i.e. between the heads of the passenger conveyor. By this arrangement no further room below the usual return path of the handrail belt is required which allows the present inventive solution be applied to movable auto walks which can be placed on a floor of the building. Preferably, the force applying device of the tensioning device for the handrail belt are adjustable so as to provide an adjustable tensioning force to the tension guide portion. If the force applying device is a tension spring then the tension spring is adjustable, e.g. by an adjustable stopper regulating the pretension of the spring. Of course, also hydraulic or pneumatic force applying devices can be adjustable as per se known in the art.

With the term "passenger conveyor", particularly escalators or moving side walks or auto walks are understood, i.e. passenger conveyors having a running handrail belt along the conveyor path be gripped by passengers for safety reasons. The handrail belt is usually - as per se known - a C-type endless belt with a middle planar section surrounded by curved side sections.

The invention could also be described as to provide the handrail drive wheel as a part of a tensioning device for setting a desired tension in the handrail belt of the handrail system of a passenger conveyor.

Hereinafter Figure 1 shows the handrail arrangement in a prior art auto walk, and

Figure 2 shows an inventive arrangement comprising a tensioning device adjacent to a handrail drive wheel in the drive head of an auto walk or escalator.

Figure 1 shows the handrail section 10 of a prior art auto walk comprising a first drive head 12 and a second tension head 14 between which an endless handrail belt 16 is running along an upper guide track 18 and a lower return path 20, in which lower return path 20 the handrail belt is supported by rollers 22.

Usually, the drive head 12 comprises a handrail drive wheel 24 which directly or via a hand rail drive belt drives the handrail belt 16. The tension head 14 comprises usually a guide surface or wheel 26 on which the handrail belt 16 is guided from the lower return path to the upper guide path. By adjusting the tension head with a pretension in direction to the corresponding conveyor end (see arrow) the tension of the handrail belt in the upper guide track 18 is adjusted to the desired level. This known solution has a disadvantage that the guide surface 26 in the tension head 14 has to be provided adjustable with respect to the fixed conveyor support. This adjustable design necessitates reinforced support structures, adjustable fixtures and more rigid and complicated structures which have an impact on the life time of the handrail belt as well as necessitate maintenance during the whole operation life.

Figure 2 shows a part of a handrail system 30 of an inventive passenger conveyor in the region of the drive head 12 which drive head comprises the handrail drive 32. The handrail drive 32 comprises a handrail drive wheel 34, The handrail belt 16 is running around a part of the circumference of the handrail drive wheel 34. Between the handrail drive wheel 34 and the handrail belt 16 a handrail drive belt 36 is running. The endless handrail drive belt 36 runs around a tensioning roller 38 and a drive roller 40, which rotates the complete arrangement of handrail drive wheel 34 and handrail belt 16. Adjacent to the lower portion of the handrail drive wheel 34 a curved tensioning device 42 is provided which comprises a tension guide portion 44, one first counter guide portion 46 which is built by a part of the circumference of the handrail drive wheel 34 in the sector m as well as second counter guide portion 48 on the side of the tension guide portion 44 remote from the handrail drive wheel 34.

The tension guide portion comprises a support 50 which is pressed by a first force applying device Fi against the handrail belt 16 in a direction perpendicular to the rotation axis r) of the handrail drive wheel 34. The support 50 carries a number of pressure rollers 52 on a curved support bar 54. The force applying device Fi may be a tensioning spring, e.g. an adjustable tensioning spring or a hydraulic or pneumatic force applying device which is per se known. Whereas the first counter guide portion 46 is built by the circumference of the handrail drive wheel in the sector m a second force applying device F ₂ is provided there which comprises a support 56 as well as a pressure rollers 58 to press the handrail belt 16 against the handrail drive belt 36 and the handrail drive wheel 34 in the sector m. By this arrangement the normal contact area M of the handrail belt and the handrail drive wheel 34 is extended by the sector m.

Also the second counter guide portion 48 comprises a support 60 and pressure rollers 62. The support 60 and pressure rollers 62 of the second guide portion are fixed with respect to the structure of the passenger conveyor so that the pressure rollers 52 of the tension guide portion 44 are pressed against the handrail belt 16 between a first counter bearing provided by the handrail drive wheel 34 in the first counter guide portion 46 and a second counter bearing formed by the pressure rollers 62 of the second guide portion 48.

By this arrangement the tension of the handrail belt 16 can be adjusted to desired level whereby also the contact area of the handrail belt 16 with the handrail drive belt 36 is increased which is improving the travel comfort of the passenger conveyor. By providing the tensioning device directly adjacent the handrail drive wheels 34 the provision of a separate first counter guide portion can be omitted and the complete arrangement can be arranged in a very compact and easily accessible manner in connection with the handrail drive.