Escalator or moving sidewalk and pallet therefore Technical background

The present invention relates to escalators or moving sidewalks for passenger transport comprising pallets running along an upper track and a lower return path, which tracks are located between two pallet return systems. Each pallet is via a first pivot connected to a first longitudinal drive means, usually an endless chain or belt, located on a first side of the pallet. Further, the pallet is via a second pivot connected to a second longitudinal drive means which is located on the opposite second side of the pallet. The longitudinal drive means are usually driven by a common drive machine or by a separate drive machine for each of both longitudinal drive means.

The pallet return system has for each longitudinal drive means a direction changing means which generally comprise sprocket wheels to guide the longitudinal drive means on their circumference.

The EP 2 138 430 Al discloses a moving sidewalk wherein the pallets are connected to the drive means on both sides of the pallet via two pivots which are offest in running direciton of the pallet. This has the advantage that the pallet is more stable during the direction changing phase between the upper track and a lower return path in the pallet return system. In this known solution the pivots ae located coaxially with the leaing roller on one pallet side and with the trailing roller on the other pallet side. This could lead to a reduced travel comfort.

Object of the invention

Accordingly, it is object of the present invention to provide an escalator or moving sidewalk, in which the pallets are stable during the direction changing phase in the pallet return systems and which offers a high travel comfort. Summary of the invention

According to the present invention this object is solved in an escalator or moving side walk with the features of claim 1. Further, the problem is solved with a pallet according to claim 15. Preferred embodiments of the invention are described in the sub claims.

The inventive escalator or moving sidewalk comprising pallets running along an upper track and a lower return path extending between two pallet return systems comprising direction changing means. Each pallet is connected to a first longitudinal drive means located adjacent a first pallet side via a first pivot and to a second longitudinal drive means located adjacent a second pallet side via a second pivot. Usually these longitudinal drive means are endless belts or chains per se known in the art. The longitudinal drive means are driven by at least one drive machine. Each pallet has a pair of leading rollers and a pair of trailing rollers to be supported on the upper track, which leading rollers run ahead of the trailing rollers in running direction of the pallet. The first and second pivots are mutually displaced or offset in running direc- tion of the pallet. The pivots are located - in running direction of the pallet - between the pallet's fixing points for the roller axles. The term running direction (R) refers to the running direction of the pallet in the upper track before entering the pallet return system.

The inventive pallet of an escalator or moving sidewalk comprises a pair of leading rollers and a pair of trailing rollers to be supported on guide tracks of an escalator or moving sidewalk, and a first pivot for connecting the pallet to a first longitudinal drive means located adjacent a first pallet side and a sec- ond pivot for connecting the pallet to a second longitudinal drive means located adjacent a second pallet side, wherein the first and second pivots are offset or mutually displaced in running direction of the pallet. According to the invention the first and second pivots are located in running direction between the pallet's fixing points for the axles of the leading rollers and trailing rollers.

According to this inventive construction the drive forces act on the pivots between the roller axes and not on the roller axes themselves. The roller axes are therefore free from any drive forces. This enhances the travel comfort of the escalator/ moving sidewalk. Following further advantages are obtained:

- The connection point structures can be kept simple as the pivots are independent of the roller axes.

- The pallet is stable during the reversing, on the other hand it is still it rela- tively centrally driven, which is good for the distribution of the drive force to the pallet. - A quite symmetrical drive force input is obtained between the opposite pallet sides

- Pivot forces acting on the pallet trying to turn the pallet around the normal axis "n" of the pallet (See Fig. 1) due to pulsation in chain or other variations in running direction do not have such a large impact on the pallet as in the above mentioned EP-patent.

- Disturbances in drive input are not as easily transmitted to the passenger.

- The roller shaft needs not be so long and the torque transmitted to the pallet is not so big in one point as in the known prior art.

Preferably the pallet comprises different fixing points for the roller axles and the pivots so that the drive force can be kept apart of the roller axles.

Preferably the total number of rollers of the pallet is four to support the pallet on the upper track. This arrangement co acts very harmonically with the offset pivots to enable a reliable, easy to install and comfortable pallet arrangement.

If the direction changing means of both longitudinal drive means in the pallet return system are coaxial (here usually as direction changing means a return wheel is provided having guide surfaces, e.g. sprockets, on its circumference for the longitudinal drive means) the direction of the pallet is to turn around as the first pivot axis first runs onto the circumference of the return wheel, whereas the second pivot axis will follow later so that via the first pivot axis the pallet is drawn with its leading edge downwards in a definite manner so that the pallet leaves the return wheels of both direction changing means upside down into the lower return path. Thus, by the displacement of both pivot axes the pallet is clearly guided in its orientation through the complete return movement.

In another advantageous embodiment of the invention, also the turning axes of the direction changing means of the pallet return system for the first and second drive means are mutually displaced by the same amount as the displacement of the first and second pivots of the pallet. By this arrangement it is ensured that both pivots run simultaneously onto and along the return wheels causing both pivots simultaneously entering an upwards or downwards slope on the return wheel of the corresponding direction changing means. Therefore, with such an arrangement the orientation of the pallet is kept unchanged during the complete turning cycle. This is advantageous for escalators or moving sidewalks with a small height, which do not allow a turning over of the pallet in the pallet return system. The pallet orientation can be kept un- changed during the complete turning cycle in the pallet return system without the necessity of any additional guide tracks or synchronizing means. Accordingly, the invention needs less moving parts as a synchronisation in the direction changing means can be eliminated. Accordingly, the installation and maintenance of such kind of escalator or moving sidewalk is essentially cheaper than in known solutions.

As no synchronization means in the direction changing means of the first and second longitudinal drive means is necessary, the safety is enhanced as no break of this synchronisation means can occur, which reduces the danger of accidents. Advantageously the size of the offset is at least half the distance between a leading roller and a trailing roller on one pallet side. This minimal size of the offset or displacement of the pivot axes clearly defines the orientation of the pallet during the turning cycle is at every moment so that less tilting of the pallet can occur which again enhances the smoothness of the pallet run in the pallet return system and accordingly also the noise generated there.

Further, the invention enables the possibility of keeping the trailing roller pair in contact with a guide track for supporting the pallet so that only the leading roller pair may run over a small gap provided in the pallet return system.

Therefore, the invention also improves the possibility of keeping the rollers of the pallet in contact with the guide track as long as possible.

Advantageously, the first pivot of the pallet is located in running direction in front of a pallet centre axis, which centre axis is perpendicular to the running direction of the pallet, whereas the second pivot is located behind said pallet centre axis. By this arrangement of the pivots, it is ensured that one pivot is located in the front half of the pallet, whereas the other pivot is located in the trailing half of the pallet or pallet body, so that this arrangement again im- proves stability of the orientation which is caused by the displacement of the pivots for supporting the pallet at the longitudinal drive means. The two pivots build in this configuration a balanced support of the pallet during the turning cycle. A further improvement of the stability of the orientation of the pallet at least during the turning cycle in the pallet return system is obtained by using a displacement of an amount which corresponds to at least a half of the length of the pallet body in running direction of the pallet. This embodiment ensures that a high force lever is obtained by the displacement of the two pivots, particularly during the turning cycle in the direction changing means. Therefore the orientation of the pallet in the turning cycle of the pallet return system can be kept by the pivots with a smaller force when the distance of the pivots, i.e. the value of the displacement in running direction is larger.

Usually, each pivot is provided by a pivot axis extending between the longitudinal drive means and a side face of the pallet body. This pivot design has revealed to be easy to install and reliable. The pivot axis is usually fixed or pivoted to a hole or bushing in the longitudinal drive mans as well as to a hole or bushing provided in the pallet body. This kind of pivot design is again very simple and reliable and ensures smooth operation and drive of the pallet by the longitudinal drive means.

It shall be clarified that the invention can be realized in any kind of escalator or moving sidewalk, which is running horizontally or in an inclined angle, e.g. between 1 and 20°, between two different floor levels. The invention can be realized in escalators or moving sidewalks wherein the pallets are turned up- side down from the upper running track to the lower return track as well as in escalators or moving sidewalks, wherein the orientation of the pallet during the direction turning cycle in the pallet return system is maintained. In this case it is only necessary that also both direction changing means for the both longitudinal drive means are displaced by the same amount as the displace- ment of the pivots of the pallet. Although the invention is directed to pass- neger transport systems it should be clear that escalators or moving sidewalks of the inventive type can also be used for load transportation. As direction changing means in the pallet return system all known types of wheels or pivoted levers can be used. Usually, the direction changing means are return wheels, e.g. provided as sprocket wheel, which guide either the longitudinal drive means or the pivots from the upper track to the lower return track.

Further, all known types of longitudinal drive means can be used in the invention as e.g. chains or belts, which are per se known in the art. In case the turning axes of both direction changing means at the ends of the escalator or moving sidewalk are mutually displaced and separate drives are used for both longitudinal drive means advantageously a synchronizing means should be provided to ensure that both longitudinal drive means run with the same velocity. This synchronizing means can be provided e.g. either as a gear or mechanical connection between both direction changing means, or as an electronic synchronizing means monitoring the velocity of the drive or drive means or of the direction changing means and regulating the drive velocity in a feedback control system. By this measure it is ensured that the return wheels of both direction changing means are rotated with the same velocity. The syn- chronization is not necessary if only one drive machine or one drive machine arrangement with several drive machines is used for driving both longitudinal drive means simultaneously.

Further, both pallet return systems at the ends of the escalator or moving sidewalk can be provided with a separate drive machine if a high output power is necessitated. In an advantageous embodiment of the invention, preferably the pallet is rota- tionally symmetric with respect to a normal axis through the centre of the wear plate of the pallet (the upper side of the pallet). This symmetric design keeps the effort for the manufacturing and installation of the pallet body low. Further the pallet is exactly balanced by the mutually displaced pivots when it is supported during the direction return cycle in the pallet return system.

It should be clear for the skilled person that the above mentioned advantageous embodiments or improvements of the invention can be combined in any manner as long as such a combination is not excluded by contradicting features of these different improvements.

Summary of the drawings Hereinafter the invention is described by the aid of embodiments in connection with the schematic drawings. In these show:

Fig. 1 an embodiment of a pallet, and Fig. 2 a pallet return system of an inventive escalator or moving sidewalk with two displaced direction changing means, keeping the orientation of the pallets unchanged during the return cycle.

Identical parts or parts with the same functions in the different Figures are designated with identical reference numerals. Fig. 1 shows an inventive pallet 10 having a pallet body 12 with a front edge 14 and a trailing edge 16, a first side 18, and a second side 20, whereby the first and second sides 18, 20 are in an escalator or moving sidewalk located adjacent to a longitudinal drive means respectively, as e.g. chains, which are not shown in this figure. The pallet 10 comprises one pair of leading rollers 22, 24 and one pair of trailing rollers 26, 28, whereby the terms "leading" and "trailing" refer to the running direction of the pallet in an upper track of the moving sidewalk. The axles of the rollers 22, 24, 26, 28 are connected to corresponding fixing points 23, 25, 27, 29 at or in the pallet, e.g. a bearing or bush- ing, and protrude from the sides 18, 20 of the pallet 10. The rollers are running on tracks (not shown) to support the pallet 10 as well as loads or persons standing on it. From both sides 18, 20 of the pallet 10 pivots 30, 32 extend in the direction of the not shown longitudinal drive means to be connected therewith. The pivots 30, 32 are connected via fixing points 31, 33, e.g. bush- ings or bearings, to the pallet body 12. Both pivot axes 30, 32 offset in running direction R of the pallet and the pivots. The pivots 30, 32 and/ or the fixing points 31, 33 of the pivots 30, 32 are further located between the pallet's fixing points 23, 25, 27, 29 for the leading rollers 22, 24 and trailing rollers 26, 28 in running direction R of the pallet 10. By this means the drive force of the pallet does not act on the rollers providing better passenger travel comfort and less wear to the rollers. The pallet further comprises parts, e.g. wear plates which are per se known and not subject matter of this invention.

The amount d of the mutual displacement between both pivots 30 and 32 in the running direction R is preferably at least half of the length 1 of the pallet in running direction R. Furthermore, both pivots or pivot axes 30, 32 are arranged advantageously with the same distance to the centre axis c perpen- dicular to the running direction. Advantageously, the pallet 10 is rotation- symmetrical through the normal n through the centre of the pallet wear plate.

The offset of the pivot axes 30 and 32 has the advantage that during the movement of the pallet 10 in a pallet return system (Fig. 2) the orientation of the pallet is stable during the complete return movement.

Accordingly, Fig. 2 shows a pallet return system 70 at one end of a moving sidewalk. The pallet 10 shown in this arrangement corresponds to the pallet 10 shown in Fig. 1. The pallet return system 70 according to the invention comprises a first direction changing means 72 and a second direction changing means 74. The essential part of the first direction changing means 72 located on the first side 18 of the pallet 10 is a first return wheel 76 carrying on its circumference a first longitudinal drive means 78, e.g. a chain. The first pivot axis 30 of the pallet 10 is connected to the first longitudinal drive means 78 via a first bushing 79. Furthermore, the first direction changing means 72 comprises a guide track element 80 for guiding a leading roller 22 of the pallet 10 through the return movement of the pallet. On the second side 20 of the pallet 10 the second direction changing means 74 comprises as essential ele- ment a second return wheel 82 for guiding the second longitudinal drive means 84. Further, it comprises the same guide track 80 as the first direction changing means 72. On the circumference of the second return wheel 82 of the second direction changing means 74, a second longitudinal drive means 84 is running, which is connected with the second pivot axis 66 of the pallet 10 via a bushing 86. Further, the upper tracks 88 and 90 of the moving sidewalk are shown on which the rollers 22, 24, 26, 28 of the pallet 10 are supported between the pallet return systems 70 on both ends of the moving sidewalk. As it can be seen from Fig. 2, the rotation axes of the first and second return wheels 76 and 82 are mutually displaced or offset by the same amount d as the offset or displacement of the first and second axes 30, 32 of the pallet 10. By this means it is realized that the pallet 10 keeps its horizontal orientation during the run through the pallet return system.

The invention can be realized with various deviations from the above embodiments within the scope of the following claims.

Fig. 2 shows the pallet return system at one end of the moving sidewalk. It should be understood that the pallet return system on the other end of the moving sidewalk is designed in the same way.