Abstract:
Method for compensating the length of a movable handrail ( 10 ) in a passenger conveyor ( 2 ) having a passenger transportation belt ( 4 ) defining at least one passenger transportation surface ( 8 ), the handrail ( 10 ) is traveling along a closed handrail path which extends through an exposed path ( 12 ) along the passenger transportation belt ( 4 ), around a turnaround means ( 14 ), through a return path ( 16 ) and around a further turnaround means ( 18 ), and which hand rail path defines a handrail plane which is substantially perpendicular to the passenger transportation surface, the method comprising the following steps: (i) turning the handrail ( 10 ) out of the handrail plane; (ii) directing the handrail ( 10 ) through a compensation means ( 38 ); and (iii) turning the handrail ( 10 ) back into the handrail plane.

Description:
FIELD OF THE INVENTION 
   The present invention relates to passenger conveyors like escalators and moving walks and particularly relates to a method for compensating a movable handrail in a passenger conveyor having a passenger transportation belt defining at least one passenger transportation surface, wherein the handrail is traveling along a closed handrail path which extends through an exposed path along the passenger transportation belt, around a turnaround means, through a return path and around a further turnaround means, and which handrail path defines a handrail plane which is substantially perpendicular to the passenger transportation surface. 
   DESCRIPTION OF THE RELATED ART 
   Such passenger conveyors are widely in use. The handrails thereof are typically made from a rubber or plastics material and are internally reinforced by reinforcing elements like reinforcing longitudinal cables which are typically made from metal material. The handrail is typically a closed loop and has a length depending of the particular application, but typically at least 30 to 35 meter. In order to compensate for manufacturing tolerances as well as shortening which occurs due to aging of the handrail, a length compensation of the handrail is typically made. To this end at least one compensation device is placed in the return path of the handrail. The manufacturing tolerances, which are substantially independent from the handrail length, are ±12.5 mm so that a length compensation of typically at least 60 mm but preferably between 60 and 75 mm or even more is desired. With existing passenger conveyors, these compensation devices consume space within the plane as defined by the handrail path. This space is, however, required for placing other components of the passenger conveyor like the passenger transportation belt guiding elements, e.g. step roller tracks, or drive elements like step chains or step chain drives. Particularly with “slim” modern passenger conveyors and particularly with class-balustrade conveyors, this space problem is acerbated. Thus, with such construction frequently the problem emerges that conventional compensation devices cannot be used due to the fact that they require too much space or a plurality of such compensation devices is required for a single handrail in order to provide sufficient compensation length. 
   SUMMARY OF THE INVENTION 
   It is the object of the present invention to provide a method and a device which obviates the space problem with the prior art passenger conveyors and which provides the designer with more flexibility for designing the arrangement of the components of the passenger conveyor in an area where space is of premium concern. 
   In accordance with an embodiment of the present invention this object is solved by a method as defined above including the following steps: 
   (a) turning the handrail out of the handrail plane; 
   (b) directing the handrail through a compensation means; and 
   (c) turning the handrail back into the handrail plane. 
   The object is further solved with a handrail compensation device having a compensation means and a means for turning the handrail around its longitudinal axis. 
   By turning or twisting the handrail around its longitudinal axis, it is possible to tilt the compensating device out of the plane of the handrail path and away from that portion of the passenger conveyor where space is particularly restricted. Particularly, it is to tilt the compensation device by an angle which is sufficient for allowing the handrail in the compensation device to travel laterally past other components which are positioned within or extending into the plane as defined by the handrail path. 
   It is preferred to turn the handrail around its neutral longitudinal axis in order to reduce or avoid unnecessary flexing work. 
   Preferably the step of turning (or deflecting) the handrail out of the handrail plane comprises turning the handrail out of the handrail plane by between approximately 2° and 30° (e.g., an oblique angle). Other values particularly within this range are possible, for example between approximately 5° and 25°, between approximately 10° and 20° and between 12° and 18°. 
   Preferably, the handrail compensation device comprises first turning means in the moving direction of the handrail, followed by the compensation means and a second turning means. The first turning means can turn the handrail by a predetermined amount in a first direction and the second turning means can turn the handrail by the same predetermined amount in the opposite direction. Such a construction shows that the handrail moves in exactly the same direction before and after the compensation device. It is also possible to not turn the handrail in one single step by the desired amount but to provide a plurality of turning means for even a continuous turning means over a prolonged distance in order to achieve a predetermined turning angle. 
   Preferably, the turning means comprises a first and second guide roller sets each for contacting the handrail on its upper side, i.e. the side which is to be contacted by the user, and its inner side, i.e. the side which faces away from the upper side wherein the second guide roller set is angularly offset with respect to the first guide roller set so that in use the handrail is turned while traveling from the first to the second guide roller set. Each guide roller set preferably forms a slit or nip through which the handrail passes. The angular difference between the first slit and the second slit defines the angular offset and consequently the handrail turning angle. Instead of the guide roller sets any other guiding elements like sliding contact plates or moving contact belts can be used. It is preferred that such alternative guide means also form a slit or nip for guiding the handrail. 
   Preferably, the second roller set comprises two inner rollers on that side which in use is adjacent to the inner side of a generally C-shaped handrail, said two inner rollers are arranged with its rotational axis substantially perpendicular to each other so that in use one of the inner rollers will contact the lateral legs of the C-shaped handrail while the other inner roller will contact the web between the legs. In order to provide for a secure guidance of the inner side of the handrail, a single roller needs a relatively large diameter which might collide with space requirements. In order to obviate this problem, an embodiment of the invention suggests using one roller or disc which has a diameter slightly smaller than the distance between the two legs of the C-shaped handrail and using a further roller whose circumferential surface contacts the web portion between the two legs and which may have a relatively small diameter. This double roller arrangement can be constructed in a way that it is only slightly extending above the thickness of the handrail. 
   Preferably, the first and second roller sets are spaced from each other by a distance that is at least two times the width of the handrail. The distance between the first and second roller sets corresponds to the length through which the handrail is turned around its longitudinal axis. It is preferred to turn the handrail in a way that the lateral legs of the C-shaped handrail do not flex or flex only at a minimum amount. This will avoid aging of the handrail due to flexing work. In order to avoid this aging, a predetermined distance is provided between the first and second roller sets. 
   Preferably, the compensation means comprises a compensation roller, in use acting against the inner side of the handrail and bulging the handrail in the direction of the upper side thereof, and wherein the second roller set is offset by a predetermined distance from the first roller set in a direction opposite to the bulging direction of the compensation roller. With such a construction the handrail is—as viewed from the side—first directed upward between the first and second roller sets and subsequently directed downward by the compensation roller before it is directed back to the second roller set of the return turning device and again downward towards its original direction. With such a construction a particularly compact compensation device can be realized. 
   An embodiment of the invention further relates to a passenger conveyor having a passenger transportation belt defining at least one passenger transportation surface and a movable handrail which is traveling along a closed handrail path extending through an exposed path along the passenger transportation belt, around a turnaround means, through a return path, and around a further turnaround means, and defining a handrail plane which is substantially perpendicular to the passenger transportation surface, further comprising a compensation means and a means for turning the handrail around its longitudinal axis. The turning means does not necessarily have to be a part of the compensation device, but can be located at other positions, preferably along the return path of the handrail. One might contemplate to guide the handrail over an extended distance in a tilted manner and possibly out of the plane of the handrail path and to position the compensation means in such portion. 
   Preferably, the passenger conveyor comprises a compensation device according to an embodiment of the invention. 
   Preferably, some or all components of the compensation device are mounted to a support element, for example a support plate. Such support element can be mounted with the predetermined turning angle in the passenger transportation device. By providing virtually all the components on the single support element, these components can be aligned with ease in the factory and can easily be assembled in the conveyor, for example attached to the conveyor trust, etc. without the need for mounting and aligning the components individually. 
   Preferably, the components of the compensation device or alternatively the support element are/is attached to precisely aligned components of the passenger transportation device. Such precisely aligned components can for example be the step roller tracks, the chain roller tracks, the balustrade holder, etc. By providing a suitable mounting arrangement, for example mating surfaces, specific fasteners, etc. it is possible to design the passenger conveyor in a way that the components of the passenger transportation device are precisely aligned by merely securing it to the respective aligned components. Such a design can substantially reduce the efforts for assembling the passenger conveyor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention and embodiments of the invention are described in greater detail below with reference to the Figures, wherein: 
       FIG. 1  shows a passenger conveyor; 
       FIG. 2  shows a compensation device in accordance with an embodiment of the invention with minimum compensation in perspective view; 
       FIG. 3  shows an end view of the compensation device of  FIG. 2  with minimum compensation; 
       FIG. 4  shows a compensation device in accordance with an embodiment of the invention in perspective view similar to that of  FIG. 2 , but in the state of maximum compensation; 
       FIG. 5  shows an end view of the compensation device of  FIG. 4  with maximum compensation; 
       FIG. 6  shows a perspective view of the compensation device in accordance with an embodiment of the invention as attached to the components of the passenger conveyor; 
       FIG. 7  shows a similar view to that of  FIG. 6  of the compensation device, but without the remainder of the passenger conveyor; 
       FIG. 8  shows a side view of the compensation device in accordance with an embodiment of the invention as attached to components of the elevator conveyor; and 
       FIG. 9  shows a perspective view of the compensation device without surrounding components. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a passenger conveyor  2  and particularly an escalator having a passenger transportation belt  4  comprised of a plurality of steps  6 , the treats thereof form a plurality of passenger transportation surfaces  8 . The escalator  2  further comprises two movable handrails  10 . Each handrail  10  is traveling along a closed handrail path which extends through an exposed path  12  where the handrail  10  is exposed to the passengers and travels in parallel to the passenger transportation surfaces  8 . The closed handrail path further comprises a upper turnaround means  14 , a return path  16  which is nearly completely covered in the Figure and runs below the passenger transportation belt  4 , and a lower turnaround means  18 . The turnaround means  14  and  18  are frequently termed newels. The escalator  2  further comprises a truss  20  for mounting the escalator in the building and for supporting escalator components like an escalator drive  22 , a chain drive sprocket  24  driving the escalator chain  26  and step roller tracks  28 . The person skilled in the art will understand that in the perspective view of  FIG. 1  some parts of the escalator  2  are broken away for showing details which would otherwise be hidden. 
   In  FIG. 1  also the glass panels  30  of the lateral balustrades  32  are shown. The glass panels  30  are at the lower end thereof supported by a glass holder profile  34  and support at their upper end a (not shown) handrail guide profile. The closed handrail path defines a handrail plane which substantially coincides with the glass panels  30  and which is substantially perpendicular to the passenger transportation surfaces  8  and extending in a vertical direction, respectively. 
     FIG. 2  shows a perspective view of a handrail compensation device  36  in accordance with an embodiment of the invention. The handrail compensation device  36  includes a handrail compensation means  38  as well as a first twisting or turning means  40  and a second twisting or turning means  42 .  FIG. 2  further shows part of the truss  20  and the glass holder profile  34 . A step roller track  44  and a step chain roller track  46  are also visible in  FIG. 2 . The handrail compensation means  38  comprises a compensation bow  48  including a plurality of compensation bow rollers as well as two back bending roller bows  50  which also comprise a plurality of back bending rollers. 
   One can further see that the handrail  10  generally is of C-shaped cross section having two lateral legs  52  protruding away from a central web  54  (see  FIG. 5 ). 
   The first and second turning means  40 ,  42  are each shown as comprising a first  56  and a second  58  guide roller sets. The first and second guide roller sets  56 ,  58  each define a slit or nib through which the web  54  of the handrail  10  is guided. The extension of the slit with the guide roller set  56  is perpendicular to the plane as defined by the handrail path. The slit of the second roller set  58  is angled with respect thereto by a predetermined amount which finally defines the twist or turning amount of the handrail. The second guide roller set  58  may comprise one or more rollers of the back bending roller bow  50 . 
   As may be seen by comparing  FIGS. 2 and 4 , the compensation bow  48  can be varied between a minimum compensation position as shown in  FIG. 2  and a maximum compensation position in  FIG. 4 . One can further see in  FIG. 4  a supporting element  60  in the form of a support plate. The holder  62  for the compensation bow is slidingly attached to the support plate  60 . 
     FIGS. 3 and 5  show end views of the handrail compensation device  36  as shown in  FIGS. 2 and 4 , respectively. One can particularly see in  FIG. 3  that the handrail  10  would collide with the step roller track  44  if the compensation device  38  would simply bend it downward as it was conventional with the prior art. There is only limited space between the handrail  10  and the upper portion of the step roller track  44 , which is not sufficient for providing the required compensation. One can clearly see in  FIG. 5  that due to the twisting or turning of the handrail and the tilted arrangement of the compensation means  38  sufficient compensation can be provided due to the fact that the handrail  10  passes laterally by the step roller track  44 . Thus  FIGS. 3 and 4  illustrate clearly how an embodiment of the invention solves the space-related problems which are inherent with the compensation devices of the prior art. 
     FIG. 6  is a further perspective view of the handrail compensation device  36  similar to that of  FIG. 4  with the compensation being near maximum. In  FIG. 6  one can clearly see the handrail which is twisted between the first guide roller set  56  and the second guide roller set  58 . One can further see in  FIG. 6  that the handrail  10  is first directed upward from the first guide roller set  56  to the second guide roller set  58  before it is directed downward through the compensation bow and then up again to the second guide roller set  58  of the second turning means which directs the handrail  10  down again and back again in its original direction. 
     FIG. 6  again shows parts of the truss  20  as well as the glass holder profile  34  and the step roller track  44 . It is to be noted that the glass holder profile  34  and the step roller track  44  are components of the escalator  2  which are very precisely aligned. Accordingly, by fixing the handrail compensation device  36  to one and/or the other of those parts, a perfect alignment thereof can achieved without the need for individual alignment of the handrail compensation device and/or its individual components. Beams  64 -which are attached to the support plate  60  attach the handrail compensation device  36  to the glass holder profile  34 . A holder  66  for the first guide roller set  56  is attached to the step chain roller profile  48 . 
     FIG. 7  is a view similar to that of  FIG. 6 , but with the components beyond the handrail compensation device  36  being omitted. In this view the second roller set  58  is better visible than in the previous Figures. One can particularly see that the second roller set  58  comprises two inner rollers  68  and  70 . These inner rollers  68  and  70  contact the inner side  72  of the handrail  10 . The inner side  72  of the handrail  10  is opposite to the upper side  74  or outer side, which is exposed to the passengers in the portion of the handrail path along the passenger transportation belt. One can particularly see that the two inner rollers  68  and  70  are arranged with its rotational axis substantially perpendicular to each other so that in use the disc-shaped inner roller  68  contacts the lateral legs  52  of the C-shaped handrail  10  while the other inner roller  70  which has the form of a cylindrical roller, contacts the web  54  between the legs  52 . The disc  68  has a slightly smaller diameter than the distance between the two legs so that it guides either one or the other leg  52 . Accordingly, the two inner rollers  68 ,  70  require by far less height than the conventional inner roller  76  in the first guide roller set  56 . This allows for directing the handrail upward between the first and second guide roller sets  56 ,  58  despite the space restriction imposed by the presence of the overlaying glass holder profile  34  (see  FIG. 6 ). 
     FIG. 8  is a side view of the handrail compensation device  36  according to an embodiment of the invention which illustrates the restricted space between the second guide roller set  58  and the glass holder profile  34 .  FIG. 9  illustrates the fixation points for the handrail compensation device. One can see that with the exception of the first guide roller set  56  all components are fixed to the support plate  60  which is secured to the underside of the glass holder profile  34  by way of the beams  64  and which is further supported by way of the support  78  to either of the two guide rails  44 ,  46 , but preferably to the step chain roller track  46 . Thus, by way of fixing the support plate  60  at three fixation points, its fixation is statically defined. The first guide roller sets  56  are each individually attached by way of holder  66  to the step chain roller track  46 .