Moving walkways

Abstract: A moving walkway which can transport users in two opposite directions comprises substantially horizontal rails (11) in the form of an endless loop defining two linear sectors (1A, 1B) connected together by two end sectors (1C, 1D). Rotatable screw rods (16) having screw grooves (16a) are arranged parallel to each linear sector. A plurality of pallets (3) is arranged to run along the rails (11). The pallets (3) have a moving roller (18) which extends into the screw grooves (16a). Each pallet carries traverse-motion control side rollers (21) in rolling contact with the side surfaces of the rails. Each pallet has a projection member (3c) which fits into a recess (3a) in the front end of the succeeding pallet. The front of each pallet is inserted beneath the preceding pallet. Adjacent pairs of pallets are interconnected by respective chains (22) which include a resilient buffer (25).

Description: The present invention relates to moving walkways for use in public facilities, such as airports, railway stations, etc., and in particular to a moving walkway for transporting users in two opposite directions. Such a moving walkway is known from US-A-4,509,429. One known moving walkway currently in use comprises sprockets rotatably mounted on both sides of the moving walkway at both ends thereof, an endless chain engaging the sprockets on both sides of the moving walkway, and a number of pallets on which users can ride and which engage the endless chains on both sides so as to be moved or circulated by rotation of the sprockets. In this known walkway, users are transported from one end to the other by the pallets moving along the upper or carrier side of a circulating route and the pallets moving along the lower or return side of the circulating route do not contribute to transportation of the users. Users cannot be transported in two opposite directions at the same time. Another known type of moving walkway is disclosed in JP-B-56-257. This walkway is illustrated in Figures 1 to 5 of the accompanying drawings, in which: Figure 1 is a partially sectional side view showing a pallet engaged with a screw shaft of the moving walkway; Figure 2 is a front view, partially in section, of a portion of the walkway shown in Figure 1; Figure 3 is a partially sectional side view showing support frames mounted on the pallet of Figure 1; Figure 4 is a side view showing the whole of the screw shaft of Figure 1; and Figure 5 is a plan view showing the screw shaft of Figure 1 arranged in a closed loop. This walkway comprises a channel section guide rail 102 having an accommodation groove 101 expending in the direction of the moving walkway, guide plates 104 arranged on the upper portions of the guide rail 102 at both sides of the groove 101, each of the guide plates 104 having a running groove 103 in its upper surface extending in the direction of the moving walkway, pallets 105 on which users can ride, steel balls 107 rotatably supported via receptacles 106 on bottom portions of the pallets 105 on both sides thereof so that the balls 107 can roll along the running grooves 103, and a screw shaft 108 with a thread 109 arranged in the groove 101 and extending in the direction of the moving walkway. The screw shaft 108 may be made of bundled steel wires so as to have flexibility. The screw shaft 108 has portions S and L with short and long pitches of the thread 109, respectively. The portions S with shorter pitch are arranged near boarding sites where users can get on or off the pallets, and the portions L with longer pitch are arranged between the boarding sites. The screw shaft 108 is connected at one end to a drive shaft of a motor 110 and is rotatably supported at its other end by a bearing 111. Each of the pallets 105 is formed, at its bottom portions close to the front and rear ends, with grooves 112 extending in the moving direction of the walkway. Each of the grooves 112 supports the upper portion of a respective support frame 14 for forward and backward movement of the frame 14 via a shaft 113 extending in the groove 112 in the direction of movement of the pallet 105. Each of the support frames 114 rotatably supports steel balls 15 at the front and rear of its bottom portion, so that the steel balls 115 contact the thread 109 of the screw shaft 108. Actuation of the motor 110 causes the support frames 114 to be pushed in the feed direction of the thread 109 as a result of the rotation of the screw shaft 108, which moves the pallets 5. The speed of movement of the pallets 105 is low at the portions S with shorter pitch of the thread 109 which are near the boarding sites and increases at the portions L with a longer pitch of the thread 109 between the boarding sites. At the transition of each pallet 105 from a portion S to a portion L or vice versa, the frame supports 114 mounted on the pallet 115 are moved horizontally along the shafts 113 so as to adjust the spacing between the support frames 114 according to any change of pitch in the thread 109. Because of its flexibility, the screw shaft 108 may be curved to follow the curved route of the pallets 105. It may, therefore, be arranged that a number of pallets 105 may be circulated by a substantially annular or loop arrangement of the screw shaft 108, as shown in Figure 5. However, in practice, a screw shaft having good flexibility is difficult to produce and therefore is not suitable for practical use. It is also not easy to arrange the screw shaft 108 in an annular or loop shape so as to circulate the pallets 105. Furthermore, in the moving walkway disclosed in JP-B-56257, adjacent pallets 105 in the direction of movement are not in contact with each other, and therefore fence or the like means must be provided for each of the pallets 105 so as to prevent users from falling off. Against this background it is the object of the invention to provide a moving walkway which can transport users in opposite directions at the same time and in a safe manner. According to the present invention, a moving walkway of the type comprising substantially horizontal rails in the form of an endless loop which defines two linear sectors, a rotatable screw rod arranged parallel to the linear sectors and having a screw groove and a plurality of pallets arranged to run along the rails, the pallets having a moving roller which extends into the screw groove, whereby rotation of the screw rod results in movement of the pallets along the linear sectors is characterised in that a screw rod is associated with each linear sector, that each pallet carries traverse-motion control side rollers for coming into rolling contact with the side surfaces of the rails, that each pallet has a projection member on the lower surface of the pallet arranged to contact the front end of the succeeding pallet, that the front of each pallet is inserted beneath the preceding pallet and that adjacent pairs of pallets are interconnected by elongate connecting means. Those pallets which are situated at positions where the screw rods are installed are moved along the rails, when the screw rods are rotated, by engagement of their moving rollers in the screw grooves. Those pallets which are situated at positions where no screw rods are provided are moved along the rails by being pulled by those pallets which are moved by the screw rods. On the end sectors of the closed loop, the projection member on the lower surface of each pallet is contacted by the front end of the succeeding pallet. The pallets on the end sectors of the loop are pushed forward by the pallets which are moved by the screw rods on the linear sectors of the loop. By virtue of the fact that the front end of each pallet is inserted beneath the rear end of the preceding pallet, a continuous walking surface is defined. It is preferred that each pallet has a recess in its front end into which the projection member of the preceding pallet fits. This ensures positive engagement of the rear end of each pallet with the front end of the succeeding pallet on the end sectors of the loop. It is preferred that the pitch of each screw groove is shorter on that portion of each screw rod which is closest to one end sector of the loop connecting the two linear sectors than it is on that portion of each screw rod which is further away from the said end sector of the loop. Two screw rods are preferably associated with each linear sector of the loop, each screw rod being closer to a respective one of the two end sectors of the loop. These features result in the speed of movement of the pallets being relatively low on portions of the linear sectors of the loop closer to the end sectors and increasing towards the middle sections of the linear sectors. In a preferred embodiment one or more further screw rods are rotatably arranged on and parallel to each linear sector of the loop between the screw rods, each of the further screw rods having a screw groove with pitch equal to the longer pitch of the thread groove of the screw rod. This results in a reduction in the tensile forces applied to the elongate connecting means interconnecting adjacent pallets. In a preferred embodiment guide rails are arranged beside the end sectors of the loop and beside portions of the linear sectors of the loop close to the end sectors, each pallet being provided with tilt-angle compensation rollers which are arranged ahead of the associated moving roller in the direction of movement of the pallet and are arranged to come into rolling contact with the lower surfaces of the guide rails. The tilt-angle compensation rollers tilt the pallets forwardly as they are moved from the linear sectors of the loop to the end sectors so that the rear end of each pallet jumps away from the front end of the succeeding pallet. The rollers release the forward tilting of the pallets as they move from the end sectors of the loop to the linear sectors so that the rear end of the pallet again overlaps with the front end of the succeeding pallet. Steps are preferably arranged at boarding sites at which users may get on or off the pallets. In a preferred embodiment the upper surface of each pallet is formed with grooves extending longitudinally, a step with comb teeth at its tip end being associated with each portion of the linear sectors of the loop closest to the end sectors such that the comb teeth are received in the grooves as the pallets pass through the said portions of the linear sectors, the base end of the step remote from the comb teeth being positioned closer to the end sectors. This results in any foreign objects in the grooves of the pallets being removed. The step may be vertically movably supported. In a preferred embodiment a rotary shaft is attached to and extends laterally from the base end of the step and is mounted for pivotal movement at a position near the base end of the step, tracer means being provided to move the step vertically in conformity with the upper surface of the pallets as they pass through the portions of the linear sectors of the loop closest to the end sectors. It is preferred that the tracer means comprises an upper arm having a base end fixed to the rotary shaft and a tip end positioned laterally of the step, a lower arm having a base end mounted for pivotal movement at a position near the tip end of the step and a tip end arranged under the upper arm so that the tip end of the lower arm is at a position closer to the associated end sector than the rotary shaft, a tracing roller pivotally mounted on the tip end of the lower arm so that the roller can roll over the upper surface of the pallets passing through the portions of the linear sectors of the loop closest to the end sectors and a connection member having one end pivotally connected to the tip end of the upper arm and the other end pivotally connected to the lower arm at a position intermediate its ends. This prevents the comb teeth from contacting the bottoms of the grooves in the pallets. It is preferred that elastic buffer means is provided between each pallet and the associated flexible connecting means. This results in a reduction in the tensile forces applied to the flexible connecting means. The end sectors of the loop may be substantially semi-circular. Alternatively, they may each comprise two arcuate sections, e.g. of circular quadrant shape, connected together by an intermediate linear portion. Further features and details of the invention will be apparent from the following description of certain specific embodiments which is given by way of example with reference to Figures 6 to 26 of the accompanying drawings, in which: Figure 6 is a plan view of one embodiment of a moving walkway according to the invention; Figure 7 is a partial plan view showing the rails and guide rails of the walkway of Figure 6; Figure 8 is a partial side view of the walkway of Figure 6; Figure 9 is a partial plan view showing the pallets shown in Figure 8; Figure 10 is a side view showing the pallets on linear sectors of the rails shown in Figure 9; Figures 11 and 12 are side and plan views showing the pallets on semi-circular sectors of the rails shown in Figure 9, respectively; Figure 13 is a partial perspective view showing the rear end of a pallet; Figure 14 is a perspective view showing the pallets and a movable step; Figure 15 is a front view of a pallet in transition between the linear and semi-circular sectors of the rails; Figures 16 to 18 are partial side views showing portions of the screw rod of different pitch; Figures 19 and 20 are plan views showing drive mechanisms for the screw rods in Figure 6; Figure 21 is a partial sectional side view showing the elastic buffer; Figure 22 is a partially sectional plan view showing the spring means; Figure 23 is a side view of the movable step and the pallets seen in Figure 8; Figures 24 and 25 are side and partial plan views showing the tracer means seen in Figure 23, respectively; and Figure 26 is a plan view showing another embodiment of rail arrangement used in the moving walkway of the invention. Figures 6 to 25 show an embodiment of a moving walkway according to the invention which comprises two annularly arranged rails 11 defining a loop, a number of pallets 3 on which users can ride and which can be circulated along and around the rails 11, chains 22 and elastic buffer means 25 for interconnecting the adjacent pallets 3, screw rods 16 and 24 for moving the pallets 3 in the direction of the rails 11, movable steps 63 positioned at boarding sites where users get on or off the pallets 3, and tracer means 68 capable of vertically moving the associated movable step 63 for engagement with an upper surface of the pallet 3. The rails 11 and guide rails 12 associated with them will firstly be described with reference to Figures 6 to 10 and 15. Each of the rails 11 comprises two linear sectors 1A and 1B arranged horizontally and parallel to each other, a semi-circular sector 1C connected to one end of each of the linear sectors 1A and 1B and a semi-circular sector 1D connected to the other end of each of the linear sectors 1A and 1B. The rails are placed on racks 23 which in turn are installed on base stands 14. The height of the upper or rolling surface of each of the rails 11 from the base stands 14 is set substantially the same. Arranged outside and inside the semi-circular sectors 1C and 1D of the radially outer and inner rails 11, respectively, are guide rails 12 which are semi-circularly curved to match the rails 11. The guide rails 12 are supported from above by pillars 13 erected on the base stand 14 at the side of the guide rails 12 remote from the rails 11. The height of the lower or rolling surface of the guide rails 12 from the base stand 14 is set substantially the same. The semi-circular sectors 1C and 1D of the rails 11 and the guide rails 12 are entirely covered with boarding platforms 2A and 2B, respectively. The pallets 3 and members associated with them will now be described with reference to Figures 8 to 15. Each pallet 3 has ridges 3g on its upper surface. The ridges 3g define grooves 3f which extend over the entire upper surface of the pallet in the direction of movement. The ridges 3g project rearwardly to provide comb teeth 3b. Provided between the comb teeth 3b are downward projections 3e for engagement with the grooves 3f of the succeeding pallet 3. The comb teeth 3b have inclined upper surfaces 3d which are gently inclined downwardly and backwardly. Each pallet 3 has a cylindrical projection member 3c fixed to the lower surface of the pallet. Each pallet 3 is notched at its front end to provide a semi-circular recess 3a into which the projection member 3c of the preceding pallet 3 may be fitted. The pallet 3 has a lateral beam 5 attached via a spacer 4 to the lower surface of the pallet and extending laterally of the pallet. The beam 5 has running rollers 6 mounted via a respective bracket 7 on the lower surface of the beam closer to its rear end so that the rollers 6 can roll on the upper surfaces of the rails 11. Arms 8, of substantially L shape when seen from the front or rear in the direction of movement of the pallet 3, are attached at their upper ends to opposite sides of the front end of the beam 5, respectively. The arm 8 has a tilt-angle compensation roller 10 mounted via a bracket 9 to a lower end of the arm 8 so that the roller 10 can roll along the lower surface of the guide rail 12. The upper ends of two arms 15 are attached to the lower surface of the beam 5 so as to be positioned between the pair of running rollers 6. Each arm 15 has a traverse-motion control roller 21 mounted on its lower end so that the rollers 21 can roll along opposite sides of respective rails 11. The pallets 3 are arranged such that the running rollers 6 contact the upper surfaces of the rails 11 and the traverse-motion control rollers 21 contact the sides of the rails 11. The front end of each pallet 3 is inserted under the preceding pallet 3. As a result, on the linear sectors 1A and 1B of the rails 11, the projection 3e on each pallet 3 is engaged in the groove 3f in the succeeding pallet 3. That is to say, the rear end of each pallet 3 is supported by the succeeding pallet 3. In transition from the linear sectors 1A or 1B to the semi-circular sectors 1D or 1C of the rails 11, the tilt-angle compensation rollers 10 begin to roll over the lower surfaces of the guide rails 12 to tilt the pallet 3 forwardly so that the rear end of the pallet 3 jumps away from the forward end of the succeeding pallet 3 and the projection 3e on the pallet 3 are disengaged from the groove 3f in the succeeding pallet 3, which enables the pallets 3 to pass along the semi-circular sectors 1D or 1C. On the semi-circular sectors 1D or 1C, the projection member 3c on each pallet 3 is fitted in the recess 3a on the front end of the succeeding pallet 3. In transition from the semi-circular sectors 1C or 1D to the linear sectors 1A or 1B of the rails 11, the tilt-angle compensation rollers 10 cease rolling over the lower surfaces of the guide rails 12 to release the forward tilting of the associated pallet 3 so that the rear end of the pallet 3 overlaps with the forward end of the succeeding pallet 3 and the projections 3e of the pallet 3 re-engage with the grooves 3f in the succeeding pallet 3. The screw rods 16 and 24 and the drive mechanisms associated with them will now be described with reference to Figures 6 to 10 and 15 to 20. The screw rods 16 are arranged at four positions, i.e. at portions of the linear sectors 1A and 1B of the rails 11 relatively closer to the semi-circular sectors 1C and 1D. The screw rods 16 are situated between and parallel with the rails 11. Each screw rod 16 is rotatably supported at its ends by bearings 20 installed on the racks 23. The screw groove 16a of the screw rod 16 is designed such that the pitch becomes greater in the order S1, M1 and L1 in which S1 refers to a boarding (getting on and off) section close to the semi-circular sectors 1C or 1D; M1 refers to a low-speed section adjacent to the boarding section S 1 and closer to the middle of the linear sectors 1A or 1B; and L1 refers to a high-speed section adjacent to the low-speed section M1 and closer to the middle of the linear sectors 1A or 1B. Each of the screw rods 16 arranged on the linear sector 1A closer to the semi-circular sector 1D and on the linear sector 1B closer to the semi-circular sector 1C is connected to a motor 19 by a rotary shaft 34, a sprocket 35 fitted over the shaft 34 and a drive chain 36 coupling the sprocket 35 and another sprocket 37 connected to the screw rod 16, so that rotation is transmitted from the motor 19 to the screw rod 16. Each of the screw rods 16 arranged on the linear sector 1A closer to the semi-circular sector 1C and on the linear sector 1B closer to the semi-circular sector 1D is connected to the motor 19 through a gear box 38 connected to the shaft 34, rotary shafts 39, 40 and 41 sequentially connected to the gear box 38, a gear box 42 connected to the shaft 41, a rotary shaft 43 connected to the gear box 42, a sprocket 44 fitted over the shaft 43, a drive chain 45 coupling the sprocket 44 to a sprocket 46 and a rotary shaft 47 over which the sprocket 46 is fitted and to which the screw rod 16 is connected, so that rotation is transmitted from the motor 19 to the screw rod 16. The screw rods 24 are arranged at two points, i.e. at the middle of the linear sectors 1A and 1B of the rails 11. The screw rods 24 are situated between and parallel with the rails 11. Each screw rod 24 is also rotatably supported via bearings (not shown) on the above-mentioned racks 23, in a manner similar to the screw rods 16. Screw groove 24a of the screw rod 24 has a pitch equal to the pitch of the screw groove 16a in the high-speed section L1 of the screw rod 16. The screw rod 24 positioned at the middle of the linear sector 1B is connected to a motor 48 by a rotary shaft 49 connected to the motor 48, a sprocket 50 fitted over the shaft 49, a drive chain 51 coupling the sprocket 50 and another sprocket 52 which is connected to the screw rod 24. The screw rod 24 arranged in the middle of the linear sector 1A is connected to the motor 48 through a gear box 53 connected to the shaft 49, rotary shafts 54, 55 and 56 sequentially connected to the gear box 53, a gear box 57 connected to the shaft 56, a rotary shaft 58 connected to the gear box 57, a sprocket 59 fitted over the rotary shaft 58, a drive chain 60 coupling the sprocket 59 with another sprocket 61 and a rotary shaft 62 over which the sprocket 61 is fitted and which is connected to the screw shaft 24. The lateral beam 5 of the pallet 3 has a support base 17 attached to the centre of its lower surface. The support base 17 has a moving roller 18 rotatably mounted on its lower end such that the roller 18 is positioned just under the projection member 3c. When the moving rollers 18 are engaged with the screw grooves 16a and 24a, the screw rods 16 and 24 are rotated so that the moving rollers 18 are moved in a direction corresponding to the rotation of the screw rods 16 and 24. As a result, the pallets 3 are moved along the linear sectors 1A and 1B of the rails 11. The speed of movement of the pallets 3 on the linear sectors is increased in the order of the boarding section S1, the low-speed section M1 and the high-speed section L1 in accordance with the pitches of the screw grooves 16a. The chain 22 and the elastic buffer means 25 will now be described with reference to Figures 10, 15, 21 and 22. The elastic buffer means 25 comprises a spring member 29 loosely fitted over a bolt 28 and capable of being compressed in the direction of movement of the pallet 3, a first seat 27a axially movably fitted over a portion of the bolt 28 close to one end of the bolt 28 and in contact with one end of the spring member 29,a first nut 28a screwed on the bolt 28 so that it contacts the end surface of the seat 27a remote from the spring member 29, a second seat 26a axially movably fitted over a portion of the bolt 28 closer to the other end of the bolt 28 and in contact with the other end of the spring member 29, a second nut 28b screwed on the bolt 28 so that it contacts the end surface of the seat 26a remote from the spring member 29 and a third nut 28c screwed on the bolt 28 into contact with the second nut 28b. The position of the second nut 28b on the bolt 28 may be adjusted to change the projection length of the bolt 28 from the second seat 26a. The first seat 27a is integral with an inner tube 27 which is positioned within the spring member 29 and encircles an intermediate portion of the bolt 28. The second seat 26a is integral with an outer tube 26 which encircles the spring member 29. The outer tube 26 has a plug 30 fitted into its end remote from the seat 26a. The plug 30 has a connection fork 30a and is retained in the tube 26 via a spring pin 30b. The fork 30a is connected to one end of a link member 32 via a pin 32a. The other end of the link member 32 is connected to the front end of a bracket 31 fixed to the above-mentioned arm 8 via a substantially horizontal pin 32b. The other end of the bolt 28 is integrally formed with a fork 28d. The fork 28d is connected to a rear end of the chain 22 via a pin 22a. The front end of the chain 22 is connected to the rear end of the above-mentioned bracket 31 via a substantially horizontal pin 22b. As a result, each of the arms 8 of each pallet 3 is connected to the corresponding arm 8 of the succeeding pallet 3 via the bracket 31 on the pallet 3, the chain 22, the elastic buffer means 25 and the bracket 31 on the succeeding pallet 3. Fixed to the outer tube 26 is a stopper member 33 which contacts the fork 28d to prevent the bolt 28 from being rotated. The movable step 63 and the tracer means 68 will now be described with reference to Figures 14 and 23 to 25. The movable step 63 is mounted on each of fixed steps 64 associated with the boarding platforms 2A and 2B. The fixed steps 64 are positioned to extend from the platforms 2A and 2B to cover the ends of the linear sectors 1A and 1B of the rails 11. The movable step 63 is formed at its tip end with comb teeth 65 which fit into the grooves 3f on the upper surface of the pallet 3. The movable step 63 has a rotary shaft 66 attached to a base end of the step 63. The rotary shaft 66 projects laterally and substantially horizontally from the base end of the step 63. The rotary shaft 66 is rotatably supported by a bearing 67 arranged near the tip end of the fixed step 64 such that the upper surface of the base end of the movable step 63 is not at a significant distance from or stepped with respect to the upper surface of the tip end of the fixed step 64. The tracer means 68 comprises an upper arm 69 having a base end fixed to the shaft 66 and a tip end positioned laterally of the movable step 63, a lower arm 72 having a base end pivoted via a pin 71 to a bracket 70 arranged near the tip end of the movable step 63 and a tip end arranged under the upper arm 69 so as to be positioned closer to the semi-circular sectors 1C or 1D of the rails 11 than the rotary shaft 66, a tracing roller 73 pivotally supported on the tip end of the lower arm 72 so that the roller 73 can roll over the upper surface of the pallet 3 passing immediately below the fixed step 64, and a connecting member 76 with one end pivoted via a pin 74 to the tip end of the upper arm 69 and its other end pivoted via pin 75 to an intermediate portion of the lower arm 72. The distance from the comb teeth 65 of the movable step 63 to the centre of rotation of the tracing roller 73 is set to a value substantially equal to the distance between two adjacent pallets which are going to pass immediately below the movable and fixed steps 63 and 64. The distance between the pins 74 and 75 is set to a value such that the comb teeth 65 fit in the grooves 3fofthe pallet passing immediately under the movable step 63 and the lower surfaces of the comb teeth 65 do not contact the bottom of the grooves 3f. In Figure 8, reference numerals 77S, 77M and 77L represent handrails made of rubber material. The handrails 77S are arranged on both sides of the walkway adjacent the linear sectors 1A and 1B of the pallets 3 to correspond to the boarding sections S1 of the screw rods 16. The handrails 77M, on both sides of the pallets 3, correspond to the low-speed sections M1 of the screw rods 16. As shown in Figure 19, torque is transmitted from the motor 19 to the handrails 77S and 77M through sprockets 78 and 79 fitted respectively over the rotary shafts 39 and 41, sprockets 82 and 83 fitted respectively over rotary shafts 80 and 81 connected to the gear boxes 38 and 42, drive chains (not shown) extending around the sprockets 78, 79, 82 and 83 and sprockets (not shown) associated with the handrails 77S and 77M. As a result, the handrails 77S and 77M are circulated in synchronisation with the movement of the pallets 3. The handrails 77L are arranged respectively on the two sides of the moving route of the pallets 3 in the linear sectors 1A and 1B at sections where the handrails 77S and 77M are not provided. As shown in Figure 20, torque or rotation is transmitted from the motor 48 to the handrails 77L through sprockets 84 and 85 respectively fitted over the rotary shafts 54 and 56, sprockets 88 and 89 respectively fitted over rotary shafts 86 and 87 connected to the gear boxes 53 and 47, drive chains (not shown) extending around the sprockets 84, 85, 88 and 89 and sprockets (not shown) associated with the handrails 77L. As a result, the handrails 77L are circulated in synchronisation with the movement of the pallets 3. The mode of operation of the moving walkway as shown in Figures 6 to 25 will now be described: Rotation of the screws rod 16 and 24 by the motors 19 and 48 causes the rollers 18 in engagement with the screw groves 16a and 24a to be moved in a direction corresponding to the rotation of the screw rods 16 and 24, which moves the pallets 3 along the linear sectors 1A and 1B of the rails 11. The directions of movement of the pallets 3 on the linear sectors 1A and 1B of the rails 11 are opposite to one another. Thus, users can be transported in two opposite directions at the same time by the single moving walkway. Those pallets 3 on the linear sectors 1A and 1B of the rails 11 whose rollers 18 are not in engagement with the screw grooves 16a and 24a are pulled via the elastic buffer means 25 and the chains 22 by the preceding pallets 3 which are moving in association with the rotation of the screw rods 16 and 24. Thus, on the linear sectors 1A and 1B of the rails 11, each pallet 3 is moved with its projections 3e engaged in the grooves 3f of the succeeding pallet 3. The rear end of each pallet 3 thus overlaps with the front end of the succeeding pallet 3. Thus, many users can be transported in safe manner. The speed of the pallets 3 is progressively increased as the moving rollers 18 are moved to the boarding section S1, the low-speed section M1 and the high-speed section L1 of the screw grooves 16a, and is then reduced again as the rollers 18 move from the high-speed section L1 to the low-speed section M1 and the boarding section S 1 of the screw grooves 16a. Consequently, at the two ends of the linear sectors 1A and 1B of the rails 11, the pallets 3 are moved at low speed and users can easily get on or get off the pallets 3. At the middle of the linear sectors 1A and 1B, the pallets 3 are moved at high speed. An excessive tensile force may potentially be applied to the chains 22 between adjacent pallets 3 when each pallet 3 starts to be pulled by its preceding pallet 3. This excessive tensile force is relieved or damped by the elastic buffer means 25. As a result, deformation of the chains 22, which could be caused by repeated application of excessive tensile forces, is prevented, thereby alleviating any impact on users riding on the pallets 3. In addition to the screw rods 16, the screw rods 24 are arranged at the middles of the linear sectors 1A and 1B. Accordingly, any tensile force applied to the chains 22 can be further reduced, which makes it possible to design the linear sectors 1A and 1B of the rails 11 rather longer. Relief of the tensile force applied to the chains 22 will prevent elongation of the links which constitute the chains 22 and any wear of the pins interconnecting the links. When the pallets 3 approach the portion of the linear sector 1A of the rails 11 closer to the semi-circular sector 1D or the portion of the linear sector 1B of the rails 11 closer to the semi-circular sector I C, the overlap of the rear and front ends of adjacent pallets 3 is increased due to the difference in the pitches of the high-speed section L1, the low-speed section M1 and the boarding section S1 of the screw grooves 16a, thereby decreasing the distance between the pallets 3. When the pallets 3 enter the semi-circular sectors 1C or 1D of the rails 11 after passing immediately under the movable step 63, the comb teeth 65 at the tip end of the movable step 63, which are fitted in the grooves 3f of the pallet 3, remove any foreign objects in the grooves 3f. The tracer means 68 move the movable step 63 vertically in accordance with the upper surface of the preceding pallet 3 so as to prevent the lower surface of the comb teeth 65 from contacting the bottom of the grooves 3f, which contributes to preventing wear of the comb teeth 65. When the pallets 3 enter the linear sectors 1A or 1B after passing under the movable step 63 from the semi-circular sectors 1C or 1D of the rails 11, the tracer means 68 move the movable step 63 vertically in accordance with the upper surface of the succeeding pallet 3 which is moving behind of the pallet 3 with its grooves 3f engaged with the comb teeth 65, which also contributes to preventing wear of the comb teeth 65. When the pallets 3 enter the semi-circular sectors 1C or 1D, the tilt-angle compensation rollers 10 begin to roll over the lower surfaces of the guide rails 12 to tilt the pallet 3 forwardly so that the rear end of each pallet 3 jumps away from the front end of the succeeding pallet 3 and the projections 3e of the pallet 3 are disengaged from the grooves 3f of the succeeding pallet 3, which enables the pallets 3 to pass through the semi-circular sectors 1D or 1C of the rails. The projection member 3c of each pallet 3 is fitted into the recess 3a on the front end of the succeeding pallet. Thus, the pallets 3 on the semi-circular sectors 1C or 1D are sequentially moved toward the linear sectors 1A or 1B as they are pushed by the pallets 3 moved by the screw rod 16 from the linear sectors 1B or 1A. When the pallets 3 are moved from the semi-circular sectors 1C or 1D of the rails 11 to the linear sectors 1A or 1B, the tilt-angle compensation rollers 10 cease rolling over the lower surfaces of the guide rails 12 and thus release the forward tilting of the pallets 3. Accordingly, the rear end of each pallet 3 overlaps with the front end of the succeeding pallet 3 and the projections 3e on the pallets 3 are re-engaged with the grooves 3f in the succeeding pallet. Figure 26 shows a further embodiment of the arrangement of the rails 11. Each rail 11 comprises two linear sectors 1A and 1B arranged horizontally and parallel to one another, four quadrant sectors 1E, 1F, 1G and 1H continuous with respective ends of the linear sectors 1A and 1B, short linear sectors 1K continuous at their ends with the opposed ends of the associated two quadrant sectors 1E and 1G, and short linear sectors 1L continuous at their ends with the opposed ends of the associated two quadrant sectors 1F and 1H. Thus, it is possible to increase the distance W between the long linear sectors 1A and 1B of the rails 11 along which the pallets 3 are transported in different directions. It is to be understood that the moving walkway according to the invention is not limited to the above embodiments and that various changes and modifications may be made. For example, in the case where the linear sectors 1A and 1B of the rails 11 are not very long, the screw rods 16 may be arranged almost over the total length of each of the linear sectors 1A and 1B to move the pallets 3. In the case where the linear sectors 1A and 1B are very long, a plurality of screw rods 24 may be installed at the intermediate portions of the linear sectors 1A and 1B to reduce tensile forces applied to the chains 22. The elastic buffer means 25 has been described as including a spring member 29; alternatively, it may utilise gas pressure or liquid viscous resistance. Instead of being installed on one end of the chains 22, the elastic buffer means 25 may be installed on each end of the chain 22. The guide rails 12 may extend further toward the centre of the linear sectors 1A or 1D than the positions shown in Figures 6 and 7, or may end short of the positions shown in Figures 6 and 7.

Claims: A moving walkway comprising substantially horizontal rails (11) in the form of an endless loop which defines two linear sectors (1A, 1B), a rotatable screw rod (16) arranged parallel to the linear sectors and having a screw groove (16a) and a plurality of pallets (3) arranged to run along the rails, the pallets (3) having a moving roller (18) which extends into the screw groove (16a), whereby rotation of the screw rod (16) results in movement of the pallets (3) along the linear sectors wherein, a screw rod (16) is associated with each linear sector (1A, 1B), characterised in that each pallet (3) carries traverse-motion control side rollers (21) for coming into rolling contact with the side surfaces of the rails (11), that each pallet (3) has a projection member (3c) on the lower surface of the pallet arranged to contact the front end of the succeeding pallet, that the front of each pallet (3) is inserted beneath the preceding pallet and that adjacent pairs of pallets (3) are interconnected by flexible connecting means (22). A moving walkway as claimed in Claim 1, wherein each pallet (3) has a recess (3a) in its front end into which the projection member (3c) of the preceding pallet fits. A moving walkway as claimed in Claim 1 or 2, wherein the pitch of each screw groove (16a) is shorter on that portion (S1) of each screw rod (16) which is closest to one end sector (1C, 1D) of the loop connecting the two linear sectors (1A, 1B) than it is on that portion (M1, L1) of each screw rod which is further away from the said end sector of the loop. A moving walkway as claimed in Claim 3 wherein two screw rods (16) are associated with each linear sector (1A, 1B) of the loop, each screw rod (16) being closer to a respective one of the two end sectors (1C, 1D) of the loop. A moving walkway as claimed in Claim 4, wherein one or more further screw rods (24) are rotatably arranged on and parallel to each linear sector (1A, 1B) of the loop between the screw rods (16), each of the further screw rods (24) having a screw groove (24a) with pitch equal to the longer pitch of the thread groove (16a) of the screw rods (16). A moving walkway as claimed in any one of the preceding claims, wherein guide rails (12) are arranged beside the end sectors (1C, 1D) of the loop and beside portions of the linear sectors (1A, 1B) of the loop closer to the end sectors, each pallet (3) being provided with tilt-angle compensation rollers (10) which are arranged ahead of the associated moving roller (18) in the direction of movement of the pallet and are arranged to come into rolling contact with the lower surfaces of the guide rails (12). A moving walkway as claimed in any one of the preceding claims, wherein the upper surface of each pallet (3) is formed with grooves (3f) extending longitudinally, a step (63) with comb teeth (65) at its tip end being associated with each portion of the linear sectors (1A, 1B) of the loop closest to the end sectors (1C, 1D) such that the comb teeth (65) are received in the grooves (3f) as the pallets pass through the said portions of the linear sectors, the base end of the step (63) remote from the comb teeth (65) being positioned closer to the end sectors (1C, 1D). A moving walkway as claimed in Claim 7, wherein a rotary shaft (66) is attached to and extends laterally from the base end of the step (63) and is mounted for pivotal movement at a position near the base end of the step (63), tracer means (68) being provided to move the step (63) vertically in conformity with the upper surface of the pallets (3) as they pass through the portions of the linear sectors (1A, 1B) of the loop closest to the end sectors (1C,1D). A moving walkway as claimed in Claim 8, wherein the tracer means (68) comprises an upper arm (69) having a base end fixed to the rotary shaft (66) and a tip end positioned laterally of the step (63), a lower arm (72) having a base end mounted for pivotal movement at a position near the tip end of the step (63) and a tip end arranged under the upper arm (69) so that the tip end of the lower arm (72) is at a position closer to the associated end sector (1C, 1D) than the rotary shaft (66), a tracing roller (73) pivotally mounted on the tip end of the lower arm (72) so that the roller (73) can roll over the upper surface of the pallets passing through the portions of the linear sectors (1A, 1B) of the loop closest to the end sectors (1C, 1D) and a connection member having one end pivotally connected to the tip end of the upper arm (69) and the other end pivotally connected to the lower arm (72) at a position intermediate its ends. A moving walkway as claimed in any one of the preceding claims further comprising elastic buffer means (25) between each pallet (3) and the associated connecting means (22). A moving walkway as claimed in Claim 10, wherein the elastic buffer means (25) comprises a spring member (29) loosely fitted over a bolt (28) and capable of compression in the direction of movement of the pallet (3), a first seat (27a) axially movably fitted over a portion of the bolt (28) close to one end thereof and in contact with one end of the spring member, a first nut (28a) screwed on the bolt (28) so that the nut contacts the end surface of the first seat (27a) remote from the spring member (29), a second seat (26a) axially movably fitted over a portion of the bolt (28) closer to the other end thereof and in contact with the other end of the spring member (29), and a second nut (28b) screwed on the bolt so that the second nut contacts the end surface of the second seat (26a) remote from the spring member 29), the elastic buffer means (25) being associated, through the second seat (26a) and the other end of the bolt (28), with the pallet (3) and the spring means (29).

Inventors: SAIT MITSURU, SHIMURA TOSHIKAZU, SAIT, MITSURU, SHIMURA, TOSHIKAZU
Applicants: ISHIKAWAJIMA HARIMA HEAVY IND, ISHIKAWAJIMA-HARIMA JUKOGYO KABUSHIKI KAISHA
Application year: 1998
Main classification: B66B23
IPC codes: B66B21