Patent Publication Number: US-9428368-B2

Title: Device for driving a handrail for an escalator or moving walkway

Description:
The invention relates to a device for driving a handrail. The handrail can be a component of an escalator or a moving walkway. The invention equally relates to an escalator or a moving walkway with such a device. 
     BACKGROUND OF THE INVENTION 
     Escalators or moving walkways comprise a circulating step belt for the transport of persons or objects, and a support structure. The step belt is bounded along its conveying direction on each side by a respective balustrade, which balustrade is arranged on a balustrade base. A handrail guided to circulate is arranged at such a balustrade along its upper terminal. The return guide of the handrail is usually integrated in the balustrade base or alternatively can be arranged in the support structure of the escalator or the moving walkway. A handrail drive driving the handrail is usually arranged at the return guide of the handrail. 
     U.S. Pat. No. 5,295,567 shows such a handrail drive of an escalator, wherein the handrail drive is arranged in a support structure of the escalator. The handrail drive comprises a drive belt guided by way of two deflecting rollers to circulate. A handrail to be driven by the handrail drive is guided at this drive belt by means of a counter-pressure roller. The handrail is moved or driven by way of a friction couple, which results therefrom, between the drive belt and the handrail. The escalator additionally comprises a deflecting curve, which is fastened to the support structure of the escalator and which is needed, due to the high dimensions of the support structure, for further guidance of the handrail. 
     However, in the illustrated solution there is the disadvantage that the escalator due to the high dimension of the support structure imposes a need for increased space in its installed state. 
     In the case of a support structure with smaller dimensions the handrail can be deflected in the immediate vicinity of the handrail drive. Such deflecting means are shown in, for example, JP-B-54-34235 and U.S. Pat. No. 3,414,109. The deflection roller, by way of which the drive belt is guided, could accordingly be equally well used as deflection roller for the handrail. This means that the handrail bearing against the drive belt executes a directional change which is considered necessary with respect to the increased demands on space conditions. In the case of detaching of the handrail from the drive belt in the course of such a joint deflection of the handrail together with the drive belt, however, a disturbing effect arises which increases wear not only of the drive belt, but also of the handrail. In addition, this effect causes unpleasant, disturbing noise. 
     BRIEF SUMMARY OF THE INVENTION 
     It is therefore the object of the invention to provide a device for driving a handrail for an escalator or a moving walkway, which device enables reduced wear of the handrail and the drive belt. 
     The object is fulfilled by a device for driving a handrail of an escalator or for driving a handrail of a moving walkway, the device comprising: a drive belt, which is deflected by way of a first and a second deflection roller and forms a contact zone, and at least one counter-pressure guide roller, which has the effect that the handrail can be guided along the entire contact zone while bearing against the drive belt and is drivable by the drive belt by means of friction couple between drive belt and handrail, wherein the device comprises a first tangential plane, which is tangential to the deflection rollers and which is formed parallel to the axis of rotation of the deflection rollers, and a second tangential plane, which is tangential to the at least one counter-pressure guide roller or one of the deflection rollers, wherein the second tangential plane is arranged parallel to the first tangential plane and the first and second tangential planes are so constructed that the deflection rollers and the at least one counter-pressure guide roller are arranged between the tangential planes, characterised in that the device comprises a deflecting element, which is arranged between the first and second tangential planes and at a spacing from the deflection roller and which ensures that a lift-off point, which bounds the contact zone, of the handrail from the drive belt is arranged at the deflection roller ahead of the region of deflection of the drive belt. 
     The object is equally fulfilled by modernisation of an escalator or moving walkway with such a device. 
     It has been recognised that the effect causing the unpleasant noise arises because not only the drive belt, but also the handrail are elastic. Consequently, changes in length of the outer surfaces of the drive belt and the handrail occur, in particular, when the handrail is separated from the drive belt in the region of a common bending or deflection. These changes in length are more pronounced the stronger the common deflection, which is executed under friction couple or adhesive couple, directly before the separation or detaching thereof. 
     At the point of separation, i.e. the lift-off point, stresses caused by the changes in length thus arise between the two directly adjacent outer surfaces of the drive belt and the handrail. These stresses are relieved by repeated dissolution of the frictional couple connection between the handrail and the drive belt in the immediate vicinity of the lift-off point. Rubbing of the handrail against the drive belt and accordingly the mentioned disturbing effect result therefrom. 
     Consequently, the deflection roller provided for the drive belt cannot be additionally employed for deflection of the handrail, although such a use of the deflection roller would make possible a very small need for space for the components for operation of the handrail and an additional propulsion for the handrail due to the increased contact area. This means that in the case of limited availability of space for installation of the device provided for drive of the handrail it would be obvious to dispense with as many components as possible for guidance of the handrail. 
     In order to not only prevent the effect causing the wear, but also to achieve a space saving by a deflection of simple design, the device for driving the handrail has to include an additional deflecting element. The deflecting element enables on the one hand space-saving guidance of the handrail as a consequence of its arrangement between the tangential planes formed by the device, although the deflecting element itself demands additional space, and on the other hand the correspondingly placed deflecting element enables gentle detaching of the handrail from the drive belt. 
     BRIEF DESCRIPTION OF THE FIGURES 
     In a development of the device the deflecting element is formed by a deflection roller. In that way, low-friction guidance of the handrail by way of such a deflecting element is made possible, which allows correspondingly smaller dimensioning of other components of the device. 
     A development of the device comprises a second deflection roller, wherein one of the deflection rollers is arranged to be adjustable in order to tension the drive belt and press it against the handrail. By means of adjustment or adjustability of one of the deflection rollers the drive belt can tighten and press against the contacting handrail. In that way, slip between the handrail and the drive belt in the region of the contact zone can be prevented, which slip can lead to a less effective drive of the handrail. It is thus possible by means of such an adjustability to dispense with devices which require additional space and which prevent such slip. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A development of the device comprises a counter-pressure guide roller which has the effect that the handrail can be guided, bearing against the drive belt, in the contact zone and is drivable or movable by the drive belt by means of friction couple between drive belt and handrail. It is possible by means of this counter-pressure guide roller to press the handrail against the drive belt, whereby a drive movement of the drive belt is transmissible to the handrail. The friction couple can in that way be maintained between drive belt and handrail along the contact zone. Beyond that, the device can comprise two counter-pressure guide rollers, wherein the at least two counter-pressure guide rollers form a roller curve. Such a roller curve comprising a plurality of counter-pressure guide rollers has the advantage of being able to press the handrail against the drive belt over a relatively lengthy contact zone without individual ones of the counter-pressure rollers having to have for the same purpose a diameter demanding a much greater space. 
     In a development of the device the deflection roller is constructed as a cogged belt pulley and the drive belt is constructed as a cogged belt. It is possible to prevent, by means of such an embodiment, slip from arising between the drive belt and deflection roller. Alternatively thereto the drive belt can be a wedge belt, preferably a poly-V-belt, and the deflection roller can form or have a guide surface corresponding with the wedge belt. In that way it is possible to dispense with special devices which for their part prevent the drive belt from slipping from the deflection roller. 
     In a development of the device the drive belt is provided to bear against a handgrip surface of the handrail within the contact zone. This handgrip surface and the drive belt are usually materials which can form a particularly good friction couple within the contact zone. 
    
    
     
       The invention is explained in more detail in the following by way of figures, in which: 
         FIG. 1  shows an escalator with a handrail; 
         FIG. 2  shows a device, which is provided for driving the handrail, with a guide roller; 
         FIG. 3  shows a device for driving the handrail, with a deflecting element according to a first variant of embodiment; 
         FIG. 4  shows a device for driving the handrail, with a deflecting element according to a second variant of embodiment; 
         FIG. 5  shows a first form of embodiment a drive belt, which is guided by a deflection roller, of a device for driving the handrail; and 
         FIG. 6  shows a second form of embodiment a drive belt, which is guided by a deflection roller, of a device for driving the handrail. 
     
    
    
       FIG. 1  shows an escalator  40 . The escalator  40  comprises a support structure  25 , a balustrade  22 , a balustrade base  24  and a handrail  6 . The handrail  6  is guided and moved to circulate. A visible part  41  of the handrail  6  can be guided along an outer edge of the balustrade  22 . A return guide  42  of the handrail  6  usually runs within the balustrade base  24  and/or within the support structure  25 , wherein the height, which is present in the installed state of the escalator  40 , of the balustrade base  24  or the support structure  25  is limited. A device  2  for driving the handrail  6  can be arranged at the return guide  42  of the handrail  6 . The device  2  is coupled with a drive motor  30 . The drive motor  30  produces the circulating, preferably reversible movement B of the handrail  6 . The components of the escalator  40  described in the description are equally usable as components of a moving walkway. 
       FIG. 2  shows a device  2  for driving a handrail  6 . The device  2  comprises a first deflection roller  7 , a second deflection roller  7 . 1  and a drive belt  1  guided to circulate. The device  2  has a contact zone  10 . The drive belt  1  is guided not only by way of the deflecting rollers  7 ,  7 . 1 , but also along the contact zone  10 . The drive belt  1  is deflected at these deflection rollers  7 ,  7 . 1  in a respective deflection region  26 ,  26 . 1  associated with the deflection roller  7 ,  7 . 1 . 
     In the installed state of the device  2  in the escalator the handrail  6  is guided or moved, bearing against the drive belt  1 , along the entire contact zone  10 . An exemplifying drive motor  30  is coupled with the drive belt  1  so that the drive belt  1  can be moved in circulation. Such a drive motor  30  can be constructed as an electric motor. The handrail  6  is drivable by means of a friction couple which is present within the contact zone  10  between the drive belt  1  and the handrail  6 . The handrail  6  moved by means of the drive motor  30  can have a movement direction  28 . 
     The contact zone  10  is limited by means of a lift-off point  18 . This means that the handrail  6  in its movement direction  28  from the lift-off point  18  moves away from the drive belt  1 . The lift-off point  18  shown in  FIG. 2  is arranged within the deflecting region  26  of the drive belt  1 , with which deflecting region  26  a first one of the deflection rollers  7  is associated. Such an arrangement of the lift-off point  18  can be caused by a guide roller  9  for guidance of the handrail  6 . Such an arrangement of the lift-point  18  leads to the undesired effect described in the introduction that not only the wear or abrasion of the drive belt  1  and the handrail  6  is increased, but also unpleasant noises are caused. 
     The device  2  comprises at least one counter-pressure guide roller  4  in order to guide the handrail  6  along, the contact zone  10 . At least two of these counter-pressure guide rollers  4  can form a roller curve  5 . 
       FIG. 3  shows a second device  2  for driving the handrail  6  of the escalator. The device  2  shown in  FIG. 3  comprises, additionally to the device  2  shown in  FIG. 2 , a deflecting element  16 . The deflecting element  16  has the effect that the lift-off point  18  is not arranged within the deflecting region  26 , which is associated with the first deflection roller  7 , of the drive belt  1 . In that way it is possible to avoid rubbing of the handrail  6  against the drive belt  1  in the immediate vicinity of the lift-off point  18 . The deflecting element  16  can be constructed as, for example, deflection roller  16 . 
     The device  2  forms a first tangential plane T′ and a second tangential plane T″. The first tangential plane T′ is arranged parallel to the axes  7 ′,  7 . 1 ′ of rotation of the deflection rollers  7 ,  7 . 1  and tangential to the first deflection roller  7  and the second deflection roller  7 . 1 . The second tangential plane T″ is arranged parallel to the first tangential plane T′ and tangential to the counter-pressure guide roller  4 . The tangential planes T′, T″ are in that case so arranged that the first and second deflecting rollers  7 ,  7 . 1  and the at least one counter-pressure guide roller  4  are arranged between these tangential planes T′, T″. For this purpose, the second tangential plane T″ can, in an arrangement of the rollers  4 ,  7 ,  7 . 1  differing from  FIG. 3 , be tangential to the first deflection roller  7  or the second deflection roller  7 . 1  instead of the counter-pressure guide roller  4 . The arrangement of the rollers  4 ,  7 ,  7 . 1  between the tangential planes T′, T″ makes it possible for the device  2  for driving the handrail  20  to be integrated in the balustrade base or in the support structure of lower height. 
     One of the deflection rollers  7 . 1  can be arranged to be adjustable by means of an adjusting device  8 , so that, for example, a re-adjustment of the device  2  during a service or assembly of the escalator is made possible. It can be ensured by means of this possibility for re-adjustment that the drive belt  1  is sufficiently tensioned and/or bears against the handrail  6  within the provided contact zone  10 . 
     Moreover, the device  2  can be so constructed that the handrail  6  can be driven by means of the drive motor  30  not only in accordance with the movement direction  28 , but also counter to this movement direction  28  in a counter-movement direction  28 ′. In the case of such a drive capability of the handrail  6  in opposite directions  28 ,  28 ′ of movement a lift-off point  18 ′ bounding the contact zone  10  can be so arranged by means of a deflecting element (not illustrated) that the contact zone  10  does not extend within the deflecting region  26 . 1  associated with a second one of the deflection rollers  7 . 1 . 
     The directional change, which is illustrated in  FIGS. 2 and 3 , of the handrail  6  in the case of deflection thereof at the guide roller  9  or the deflecting element  16  can take place in less pronounced manner so as to, for example, expose the handrail  6  to lower loads. In order to further reduce these loads on the handrail  6  or to improve drivability of the handrail  6  by the drive belt  1  a handgrip surface  20  of the handrail  6  can be guided in the contact zone  10  to bear against the drive belt  1 . 
       FIG. 4  shows a third device  2  for driving the handrail  6  of the escalator. The device  2  comprises a deflecting roller  7 , a deflecting element constructed as a deflecting member  16 ′, a drive belt  1  and a contact zone  10 . The drive belt  1  is deflected at this deflection roller  7  in a deflecting region associated with the deflection roller  7 . The handrail  6  is provided to be guided along the contact zone  10  while bearing against the drive belt  1 . The deflecting member  16 ′ has the effect that the handrail  6  does not bear against the drive belt  1  in the deflecting region  26  associated with the deflection roller  7 . The deflecting element is preferably so formed or constructed that a low level of friction is present between this deflecting element and the moved handrail  6 . Accordingly, the deflecting member  16 ′ can be coated with, for example, low-friction PTFE material and/or with polyoxymethylene (POM) and/or polyamide (PA). 
       FIG. 5  shows a first form of embodiment of a drive belt, which is guided by a deflection roller, of a device for driving the handrail.  FIG. 5  in that case shows a detail of the device  2 , which is shown in  FIG. 4 , in a sectional illustration A-A. The drive belt shown in accordance with  FIG. 4  is constructed as a wedge belt  1   a  and the deflection roller shown in accordance with  FIG. 4  is correspondingly constructed as a belt pulley  7   a , preferably as a poly-V-belt. This means that the deflection roller  7   a  forms a guide surface corresponding with the wedge belt  1   a . Consequently, the belt pulley  7   a  has a grooved-pulley cross-section  50  and the wedge belt  1   a  has a grooved-wedge-belt cross-section  50 ′. 
       FIG. 6  shows a second form of embodiment, which is an alternative to  FIG. 5 , of a drive belt, which is guided by a deflection roller, of a device for driving the handrail.  FIG. 6  in that case shows a detail C of the device  2  shown in  FIG. 4 . The drive belt shown in accordance with  FIG. 4  is constructed as a cogged belt  1   b  and the deflection roller shown in accordance with  FIG. 4  correspondingly constructed as a cogged belt pulley  7   b , which means that the cogged belt pulley  7   b  forms a guide surface corresponding with the cogged belt  1   b.