FIELD OF THE INVENTION The present invention relates to a people mover as defined in the preamble of claim 1.

BACKGROUND OF THE INVENTION In prior-art sliding walkway arrangements, people are moved on successive conveyor elements, such as pallets, which have been arranged as an endless loop to form a moving track having a substantially continuous conveying surface. The conveyor elements are generally connected to each other by a power transmission chain, which is driven so as to move the elements. The chain may be connected to the conveyor element e.g. by means of a pin attached to the mid part of the conveyor element, said pin being mounted in bearings permitting it to rotate relative to the conveyor element frame. There are also other types of solutions, in which no separate power transmission chain is used but the conveyor elements are linked directly to each other via knuckle joints, so the elements in themselves form a chain-like structure. The conveyor elements generally move through the entire length of their track while guided by guide rails, which have been arranged to support the conveyor elements as they are moving. In the arrangement, the guide rails impart vertical support to the conveyor elements via supporting rollers, for which purpose the conveyor element loop comprises a number of supporting rollers attached at regular distances to the conveyor element loop. The conveyor element loop generally comprises an upper track portion, i.e. a conveying portion within which the conveyor elements can be utilized by pas- sengers (walking or standing on it), and a lower track portion, i.e. a return portion in which the conveyor elements move below the conveyor elements of the conveying portion and in an opposite direction relative to these. Each end of the conveyor is provided with an arrangement for changing the direction of the conveyor elements and moving them between the conveying portion and the return portion. In prior-art solutions, the supporting rollers used are hard rollers.

A problem inherent in prior-art solutions is a rumbling noise caused by the conveyor elements moving on the guide rails. This noise, is unpleasant to the passenger and an- noys him/her during the whole passage on the conveyor. An additional problem is that noise is produced when the conveyor element is moving from the upper track to the lower track (or vice versa) and the supporting roller of the conveyor element comes off contact and back into contact with the guide rails. Noise can be produced e.g. at the instant of change of grip, when the roller changes from guidance by one guide rail to guidance by the other guide rail and may hit the guide rail surface, producing noise. OBJECT OF THE INVENTION

The object of the invention includes elimination of some of the above-mentioned drawbacks of prior-art solutions. A specific object of the invention is to create a people mover, preferably a sliding walkway, sliding staircase or equivalent, that is farther developed than earlier solutions. The invention aims at producing one or more of the following advantages, among other things:

Achieving a people mover in which the noise produced by the conveyor element is reduced.

Achieving a people mover which has less rumble than earlier solutions, without involving disadvantages in respect of rolling resistance and therefore energy consumption.

- Achieving a people mover which has less rumble than earlier solutions, without impairing the wear resistance of the supporting rollers or increasing their susceptibility to different impacts to a critical degree. Wear or damage caused by impacts would lead to noise problems.

Achieving a people mover in which, in the region of direction change of the conveyor element, the noise caused by impacts and changes in the support force between the conveyor element and the guide rail part guiding it can be reduced.

Achieving a people mover in which the conveyor element is light in weight but causes less noise than in earlier solutions. Especially in the case of light loads, the supporting rollers in earlier solutions are noisy.

BRIEF DESCRIPTION OF THE INVENTION

It has been established that the noise produced by a conveyor element in a straight portion is due to the rolling of the supporting rollers against the guide rail. Especially when the people mover is running with a small load, the rumble problem has been found to be serious. The invention is based on the idea that it is possible to find for the supporting rollers of the conveyor advantageous properties that will render several problems non-critical, and if a set of supporting rollers having advantageous properties is selected, then the problems can be significantly reduced.

In the people mover of the invention, the people mover, which preferably is a sliding walkway or a sliding ramp, comprises conveyor elements, which are designed to support and move passengers and arranged as an endless conveyor element loop, and a power source for driving the conveyor element loop, and which sliding walkway comprises guide rails supporting the conveyor elements, which are arranged to move on said guide rails and to receive vertical support from them via supporting rollers, for which purpose the conveyor element loop comprises a number of supporting rollers. The conveyor element loop comprises a number of conveyor elements, each one of which is arranged to receive vertical support from the guide rail via one or more supporting rollers, the rim cover of said supporting roller being made of a polymer that has a hardness of at least 90 Shore A and at most 94 Shore A. By using rollers like this, advantages as mentioned above are achieved in sliding walkways and ramps. In particular, the rolling rumble of the supporting roller is reduced from the level achieved heretofore.

In a further developed embodiment of the invention, at least 80%, more preferably at least 90%, most preferably all of the conveyor elements of the people mover are arranged to take vertical support from a guide rail via (one or more) supporting rollers whose rim cover is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A. By choosing the rollers in this way, an advantageous distribution is achieved whereby a reduction of noise can be obtained with small investments.

In a further developed embodiment of the invention, at least 80%, more preferably at least 90%, most preferably all of the conveyor elements of the people mover are arranged to receive vertical support from a guide rail via (one or more) supporting rollers whose rim cover is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A, and that the hardness of the rim cover of at least most of said supporting rollers, preferably at least 80%, more preferably at least 90%, most preferably all of them is at least 92 Shore A and at most 94 Shore A. This distribution produces an advantageous noise reduction with moderate investments . The advantage is based on the roller hardness distribution. A study of the effect of roller hardness on the noise has now been carried out, and it has been established that it would be reasonable to optimize the roller hardness distribution, because it has been found that a significant circumstance is the fact that, due to the manufacturing tolerances, there are sur- prisingly large mutual differences in the hardness of the supporting rollers of one and the same people mover. The supporting rollers being used include rollers considerably differing from the desired hardness. There are hardness differences between production lots, and rollers from different production lots are in use. As there is a large number of too hard supporting rollers among those in use, the drawbacks regarding noise have not been eliminated although a certain target has been set for roller hardness values. Thus, the noise problems have not been eliminated even if the average of the roller hardness values is as desired. When as large a proportion as possible of the supporting rollers selected for a people mover are within the most preferable range in question, advantages as re- ferred to above are achieved.

In a further developed embodiment of the invention, at least 80%, more preferably at least 90%, most preferably all of the conveyor elements of the people mover are ar- ranged to receive vertical support from a guide rail via supporting rollers whose rim cover is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A, and that at least most of said supporting rollers, preferably at least 80%, more preferably at least 90%, most preferably all of them have a rim cover of a hardness of at least 92.5 Shore A and at most 93.5 Shore A. In this way, a greater reduction of noise is achieved than in the above-described embodiments, yet still with moderate investments.

In a further developed embodiment of the invention, the aforesaid supporting roller via which the conveyor element is arranged to receive vertical support from the guide rail is rotatably mounted on the conveyor element (e.g. by means of an axle) .

In a further developed embodiment of the invention, at most 10% of all the supporting rollers of the people mover have a polymer rim cover of a hardness differing from the range of 91-94 Shore A.

In a further developed embodiment of the invention, the people mover comprises at each lateral edge of the said conveyor element a supporting roller of the above- specified kind, and that the sliding walkway comprises first guide rails for the supporting roller at a first edge of the conveyor element and second guide rails for the supporting roller at a second edge of the conveyor element .

In a further developed embodiment of the invention, the hardness of the polymer rim cover of substantially all of the supporting rollers of the people mover is 92.5-93.5 Shore A. The advantage is a reduced rolling rumble.

In a further developed embodiment of the invention, the aforesaid polymer rim cover has a thickness of 5-7 mm. The advantage is a reduced rolling rumble.

In a further developed embodiment of the invention, the said supporting rollers have a diameter of 40-70 mm, most preferably 50-60 mm. The advantage is a reduced rolling rumble. The noise problems of small-diameter rollers can thus be reduced. Especially if the hardness is within the above-specified range and the thickness of the polymer rim cover is as specified above, this is an advantageous roller diameter.

In a further developed embodiment of the invention, the aforesaid supporting roller has a bearing inside its polymer rim cover, through which bearing is passed an axle which is secured to the conveyor element which receives vertical support from the guide rail via the supporting roller in question. In a further developed embodiment of the invention, the polymer rim cover of the aforesaid supporting roller has been cast directly onto the bearing inside the polymer rim cover. In this way, a simple structure and efficient noise suppression are achieved.

- In a further developed embodiment of the invention, the aforesaid polymer rim cover is a substantially rotary- symmetric layer, which comprises a load-bearing outer sur- face extending in the axial direction of the supporting roller.

In a further developed embodiment of the invention, the aforesaid polymer is polyurethane . In this way, an advan- tageous compromise of several properties is achieved. The wear properties, workability and hardness range of the material are advantageous .

In a further developed embodiment of the invention, the aforesaid polymer is polyethylene. The wear properties, workability and hardness range of the material are advantageous. Besides, the material is cheap.

- In a further developed embodiment of the invention, the conveyor elements are arranged to move on the aforesaid supporting rollers, supported by the guide rails in the conveying and return portions.

In a further developed embodiment of the invention, the conveyor elements are arranged to receive vertical support from the guide rails in the portion between the direction change areas .

In a further developed embodiment of the invention, the people mover is a device designed to be mounted on a flat surface . In a further developed embodiment of the invention, the motor of the people mover is placed above the level of the floor surface surrounding the conveyor. In a further developed embodiment of the invention, the conveyor elements of the conveyor never get below the floor surface surrounding the conveyor.

In a further developed embodiment of the invention, the conveyor elements are arranged to move on the aforesaid supporting rollers while supported by the guide rails in the conveying and return portions, and that the guide rails in the conveying and return portions are disposed at least substantially in their whole length above the floor surface surrounding the conveyor.

In a further developed embodiment of the invention, the supporting rollers of substantially all of the conveyor elements in the conveying portion are at the same level relative to each other. The above-mentioned roller properties are thus advantageous and it is not necessary to provide any space for additional noise isolation in the narrowly built structure, where the rollers are located close to the passenger.

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In a further developed embodiment of the invention, the people mover is a sliding walkway or sliding ramp, which comprises a conveying portion within which the conveyor elements can be utilized by passengers, and that the con- veyor elements comprise an upper surface forming a supporting plane, and that the upper surfaces of substantially all of the conveyor elements within the conveying portion are at the same level relative to each other. The above-mentioned roller properties are thus advantageous and it is not necessary to provide any space for additional noise isolation in the narrowly built structure, where the rollers are located close to the passenger. In a further developed embodiment of the invention, the support force between the guide rail and a supporting roller of a non-loaded conveyor element within the conveying portion is below 100 N, preferably 40-80 N.

In a further developed embodiment of the invention, the weight of the conveyor element is below 35 kg, and it has exactly 2, 3 or 4 supporting rollers mounted on it. In such conveyor elements, the above-mentioned hardness val- ues produce less noise as compared to earlier solutions, and thus a light-weight conveyor element can be made less noisy even in the non-loaded state.

In a further developed embodiment of the invention, the conveyor element weighs 20-35 kg and has alone 4 supporting rollers mounted on it, or that the conveyor element weighs 7-18 kg and has alone 2 supporting rollers mounted on it, or that the conveyor element weighs 7-16 kg and has 4 supporting rollers mounted on it, each one of which is also mounted on the conveyor element in front of or behind the conveyor element in question. In such conveyor elements, the above-mentioned hardness values produce less noise as compared to earlier solutions, and thus a lightweight conveyor element can be made less noisy even in the non-loaded state.

In a further developed embodiment of the invention, the weight of the conveyor element divided by the number of supporting rollers mounted on it is at most 8 kg/roller.

Inventive embodiments are also presented in the description part and drawings of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims below. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of explicit or implicit sub-tasks or from the point of view of advantages or sets of advantages achieved. In this case, some of the definitions contained in the claims below may be superfluous from the point of view of separate inventive ideas. Within the framework of the basic inventive idea, the features of different em- bodiments of the invention can be applied in connection with other embodiments. Each embodiment can also alone form a separate invention irrespective of the other embodiments. LIST OF FIGURES

In the following, the invention will be , described in detail by the aid of a few examples of its embodiments, with reference to the attached drawings, wherein

Fig. 1 is a three-dimensional representation of the principle of the people mover of the invention.

Fig. 2 presents a more detailed view of a supporting roller of the people mover in Fig. 1

Fig. 3 presents a partial lateral view of the sliding walkway of Fig. 1.

Fig. 4 illustrates an alternative embodiment which can be used to implement the sliding walkway of Fig. 1.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 represents a people mover 1 according to the invention. The people mover 1 is a sliding walkway, which comprises conveyor elements 2 for supporting and moving passengers, arranged to form an endless conveyor element loop (only part of which is shown) . The conveyor elements comprise an upper surface, which upper surface may have a comb-like shape and which upper surface forms a supporting plane. The sliding walkway 1 comprises a conveying portion, and when the conveyor elements are within this por- tion, they can be utilized by passengers. The upper surfaces of substantially all the conveyor elements in the conveying portion are at the same level relative to each other. The sliding walkway 1 comprises guide rails (Gl, G2) extending longitudinally in the conveying direction and having a straight supporting surface, the conveyor elements 2 being arranged to move supported by said guide rails, and from which guide rails (Gl, G2) the conveyor elements 2 are arranged to receive vertical support via the supporting rollers 4, which roll in .contact with the guide rail under them. For this purpose, the conveyor element loop comprises a number of supporting rollers at regular distances from each other. The pallets 2 are ar- ranged closely one after the other so as to form a substantially continuous conveying surface (only some of the pallets are shown) and connected to a power transmission chain or equivalent 6 by means of coupling elements 5, said power transmission chain or equivalent 6 (e.g. ar- ticulated chain or belt) being arranged to move the pallets 2 with power transmitted from a motor 3. The power transmission chain 6 is implemented as an endless loop and passed around turning elements, which most preferably are toothed wheels, and as the chain is passing around the turning elements, it reverses the direction of motion of the pallet and simultaneously moves the pallet between the upper and lower tracks, i.e. between the conveying portion and the return portion. The people mover 1 additionally comprises upper-track guide rails Gl and lower-track guide rails G2 , the conveyor elements 11 being arranged to move along these guide rails while supported by them, by having the supporting roller 4 of the conveyor element guided by the guide rail. The conveyor element loop comprises a number of conveyor elements 2, each one of which is arranged to receive vertical support from the guide rail (G1,G2) via one or more supporting rollers^, the rim cover 9 of said supporting roller 4 being made of a polymer that has a hardness of at least 90 Shore A and at most 94 Shore A. In this way, a reduced noise level is achieved. More pre- cisely speaking, the supporting rollers are so selected that a large proportion of the conveyor elements 2 of the people mover, in particular at least 80%, more preferably at least 90% and most preferably all of the conveyor ele- ments of the people mover are arranged to receive vertical support from a guide rail via a supporting roller 2 whose rim cover 9 is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A. Implementing this large a proportion of the rollers as rollers having an advantageous hardness leads to a low noise level and a set of rollers of uniform quality behaving in substantially the same way. The selection can be carried out by selecting via test measurements or by ensuring in other ways that the set of supporting rollers does not include a large number of too hard or too soft rollers. It is to be noted that manufacturing tolerances are often very wide, so that, to achieve an advantageous distribution, attention has to be paid to the manufacturing tolerances. The selection can be facilitated by implementing the roller manufacturing process in such a way that the tolerances are narrow, e.g. +-1 Shore A, in which case no separate selection step is required. The noise produced by the rollers can be further reduced by still more strictly controlling the hardness distribution towards the optimal values so as to achieve more advantageous properties. This can be done by selecting the rollers more accurately so that, as stated above, at least 80%, more preferably at least 90% and most preferably all of the conveyor elements of the people mover are arranged to receive vertical support from a guide rail via a supporting roller whose rim cover is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A, and in addition so that at least most of the said supporting rollers, preferably at least 80% , preferably at least 90% of the supportitig rollers (whose hardness is 90-94 as stated above) have a rim cover in which the polymer hardness is at least 92 Shore A and at most 94 Shore A. The noise produced by the rollers can be further reduced by still more strictly controlling the hardness distribution towards the optimal values so as to achieve more advantageous properties. This can be done by selecting the roll- ers more accurately so that, as already stated, at least 80%, more preferably at least 90% and most preferably all of the conveyor elements of the people mover are arranged to receive vertical support from a guide rail via a sup- porting roller whose rim cover is made of a polymer having a hardness of at least 90 Shore A and at most 94 Shore A, and in addition so that at least most of the said supporting rollers, more preferably at least 80%, most preferably at least 90% of the supporting rollers have a rim cover in which the polymer hardness is at least 92.5 Shore A and at most 93.5 Shore A.

The aim is to ensure that the hardness of all the supporting rollers of the people mover falls within the range of 90-95 Shore A, more preferably within the range of 91-94 Shore A as mentioned above. Therefore, preferably at most 10% of all the supporting rollers of the people mover have a polymer rim cover of a hardness differing from this (91- 94 Shore A) range. Very advantageous effects are achieved when the hardness is close to 93 Shore A. Thus, an excellent effect is achieved if even substantially all of the supporting rollers of the people mover have a polymer rim cover of a hardness in the range of 92.5-93.5 Shore A. As to the general construction of the people mover, it can be stated in more detail that the conveyor 1 comprises at each side edge of the conveyor element two supporting rollers of the kind specified above, and the sliding walkway comprises first guide rails for the supporting rollers at a first edge of the conveyor element and second guide rails for the supporting rollers at a second edge of the conveyor element. The people mover 1 proposed comprises on opposite sides of the pallets preferably identical guide rail arrangements (for the sake of clarity, only one G2 of the lower guide rails is shown in the figure) . Each lower- track guide rail G1,G2 comprises a guide surface, the conveyor elements 2 being guided to run along said guide surface while supported by the same via the supporting roll- ers. The number of supporting rollers could also be different from that suggested, e.g. two supporting rollers for each conveyor element, one at each side edge. Alternatively, successive conveyor elements 2 could be supported by a supporting roller 4 common to both, for example if the supporting roller were placed as shown in Fig. 4 on the axle line of the hinge between them in a conveyor type in which successive pallets are hinged together. The said supporting roller 4, via which the conveyor element is ar- ranged to receive vertical support from the guide rail, is rotatably mounted on the conveyor element via an axle pin.

The conveyor elements of the conveyor 1 are arranged to move on the aforesaid supporting rollers and supported by the guide rails in the conveying and return portions, i.e. by the upper guide rails and lower guide rails in the figure. In this arrangement, the conveyor elements receive vertical support from the guide rail in the track portion between the regions R of direction change of the conveyor elements. The people mover 1 is a sliding walkway which is designed to be mounted on a smooth surface, such as a non- pitted floor, and in which the motor is placed above the level of the floor surrounding it in its immediate vicinity, preferably inside a hand rail. Neither do the con- veyor elements of the conveyor go below the floor surface surrounding the conveyor at any point during their travel. The conveyor elements are arranged to move on the aforesaid supporting rollers while supported by the guide rails in the conveying and return portions, and the guide rails in the conveying and return portions are placed at least substantially in their whole length above the floor surface surrounding the conveyor. Since this solution is designed to be installed on top of a floor, its structures can not be implemented as structurally heavy construc- tions. In such a structure, the supporting rollers and the planes supporting the conveyor elements run/extend at the same level in the conveying portion and in the return portion and the noise problem originates near the user, be- cause the solution is designed to produce a flat structure. In a structure like this, isolating the frame parts would be difficult and the noise problem would be significant. Such a people mover is easy to install or even to relocate and reinstall.

Fig. 2 presents a more detailed view of the supporting roller 4,4' used in the people mover of Fig. 1. The size of the roller is most preferably such that the polymer rim cover 9 has a thickness of 5-7 mm. the diameter of the supporting rollers is 40-70 mm, most preferably 50-60 mm. Inside the polymer rim cover 9 of the supporting roller 4,4' is a bearing 10, and fitted to pass through the bearing is an axle (not shown) , which is secured to that con- veyor element 22' which receives vertical support from the guide rail (Gl, G2) via the supporting roller in question. The polymer rim cover 9 of the supporting roller has been cast directly onto the bearing 10 inside the polymer rim cover 9. The polymer rim cover 9 is a substantially rota- tion-symmetrical layer, which comprises the axial outer bearing surface S of the supporting roller. The polymer material of the rim coat is most preferably polyurethane , due to the wear resistance and malleability of this material. Another advantageous alternative would be polyethyl- ene, which likewise has fairly good corresponding properties. In the figure, the axle secured to the conveyor element 2 or 2 ' is depicted in broken lines.

Fig. 3 presents a partial side view of the sliding walkway of Fig. 1. The sliding walkway comprises at each lateral edge of the aforesaid conveyor element two supporting rollers of the type specified above, of which the supporting rollers at one lateral edge are visible in the figure. Thus there are exactly' four supporting rollers mounted alone on the conveyor element shown. Such a conveyor element weighs preferably 20-35 kg, more preferably 25-32 kg, in which case the above-mentioned specifications for the material hardness of the rollers are advantageous. Fig. 4 presents an alternative embodiment which can be used to implement the sliding walkway of Fig. 1. The manner in which the supporting rollers are attached to the conveyor elements and the number of supporting rollers differ from those in the solution presented in Fig. 3. Furthermore, the dimensions of the conveyor element are different. Moreover, in this solution it is not necessary to use a separate power transmission means 6. In other re- spects, this solution corresponds to the above description. In this embodiment, each conveyor element comprises exactly 4 supporting rollers mounted on it, each one of which is also secured to the conveyor element in front of or behind the conveyor element in question. In this solu- tion, too, there are thus two rollers mounted on either lateral edge of each conveyor element. The weight of such a conveyor element is preferably 7-8 kg, more preferably 8-15 kg, in which case the above specified, roller material hardness values are particularly advantageous.

In yet another alternative embodiment, the conveyor element weighs 7-16 kg and has exactly 2 supporting rollers mounted on it alone. In other respects, the solution corresponds to that presented in Fig. 3.

Generally speaking, in an advantageous solution the conveyor element has a weight below 35 kg and 2, 3 or 4 supporting rollers mounted on it. The weight of the conveyor element divided by the number of supporting rollers mounted on it is preferably at most 8 kg/roller. Similarly, the weight of the conveyor element divided by the number of supporting rollers mounted on it is preferably at least -2 kg/roller. Thus, the support force between the supporting roller of a non-loaded conveyor element and the guide rail is low, advantageously below 100 N, preferably 40-80 N. In such conveyor elements, the above-specified hardness values produce less noise as compared to earlier solutions, and therefore it is possible to form a light- weight conveyor element that is less noisy than before even in the non- loaded state.

The figures show a sliding walkway, but a corresponding construction can be implemented in a sliding ramp. It is obvious to the person skilled in the art that the invention is not restricted to the embodiments described above, wherein the invention has been described by way of example, but that many variations and different embodiments of the invention are possible within the framework of the inventive idea defined in the claims below. The invention can be utilized in different people movers, such as sliding walkways, escalators, sliding ramps and corresponding structures, so the conveyor element may be e.g. an escalator step. The invention can be utilized at least in solutions where the conveyor element remains in the same position during direction change. Likewise, the invention can be utilized at least in solutions where the conveyor element turns upside down during direction change.