WO2013052032A1

WO2013052032A1 - Drive assembly for a passenger conveyor

Info

Publication number: WO2013052032A1
Application number: PCT/US2011/054597
Authority: WO
Inventors: Chan-Jong Park; Alois Senger
Original assignee: Otis Elevator Company
Priority date: 2011-10-03
Filing date: 2011-10-03
Publication date: 2013-04-11

Abstract

A drive assembly (70, 170, 270) for a passenger conveyor includes a plurality of pallets (22) defining a longitudinal pallet path (36). First and second cog-link assemblies (100, 102) include a series of first pins (106) and a series of second pins (112), respectively. First and second drive sprockets (90, 94) operatively engage the first and second pins (106, 112). A motor (72) is operatively coupled to the first and second drive sprockets (90, 94) by a gear drive configured to rotate the drive sprockets (90, 94) in opposite directions. The drive sprockets (90, 94) may rotate about sprocket axes that are substantially perpendicular to a longitudinal pallet path (36), thereby giving the assembly a low height profile. The pins (106) of the cog-link assemblies (100, 102) may be spaced at a reduced pitch distance, thereby reducing vibration and noise caused by the polygon effect. Simultaneous engagement between two drive sprockets (90, 94) rotating in opposite directions and the cog-link assemblies (100, 102) provides a self-alignment feature for the drive assembly (70, 170, 270).

Description

DRIVE ASSEMBLY FOR A PASSENGER CONVEYOR

Field of the Disclosure

[0001] The present disclosure generally relates to passenger conveyors and, more particularly, to apparatus for driving pallets used in passenger conveyors.

Background of the Disclosure

[0002] Passenger conveyors, such as moving walkways, typically include a plurality of pallets that move along a path to carry passengers from one location to another.

Conventional arrangements include a pallet chain having a plurality of links associated with the pallets. The pallet chain moves in a loop corresponding to the loop followed by the pallets. Two direction reversing sprockets are provided at the ends of the loop, so that the loop traverses an upper pallet path in a first direction, during which pallets are positioned to carry passengers, and a lower pallet path in a second, opposite direction, during which pallets are returned to the entrance of the moving walkway. A drive assembly for the moving walkway is typically coupled to one of the direction reversing sprockets, and includes a motor and a drive chain or belt that engages the sprocket to cause the desired movement of the pallets.

[0003] In certain applications, it is desirable for the moving walkway to have a low profile, thereby to reduce the amount of space needed for the walkway and/or to reduce installation costs. As noted above, conventional drive assemblies use one of the direction reversing sprockets, and therefore the size of the sprocket influences the height profile needed to accommodate the drive assembly. Accordingly, while a smaller sprocket diameter may reduce the walkway profile, there are practical limitations, such as pallet size, that require a minimum sprocket size.

[0004] It is also generally desirable to minimize the polygon effect associated with conventional drive assemblies. The polygon effect is observed when a chain, which is made of a plurality of linear segments, travels over the radius of a sprocket, thereby causing the linear chain speed to vary. In a conventional moving walkway, where a large sprocket is driven to rotate the pallet chains, the polygon effect causes vibrations and noise throughout the system. A known way to reduce the polygon effect is to reduce the chain pitch, which is the distance between adjacent pins in the chain, so that the chain can more closely match the sprocket radius. To accommodate a reduced pallet chain pitch, a pallet chain band must have a smaller pitch and the pallets must have a shorter length, which increases manufacturing costs. An alternative solution to minimize the polygon effect is to increase the number of teeth on the sprocket, however this also results in an increased amount of space needed to accommodate the larger sprocket. Consequently, the conventional approaches to reducing the polygon effect conflict with the desires to minimize installation space and reduce manufacturing costs.

Summary of the Disclosure

[0005] According to certain aspects of this disclosure, a drive assembly is provided for a passenger conveyor having a plurality of pallets defining a longitudinal pallet path. The drive assembly includes a motor, a first drive sprocket operatively coupled to the motor, and a second drive sprocket operatively coupled to the motor. A first cog link assembly includes a series of first engagement surfaces configured to operatively engage the first drive sprocket. A second cog link assembly is spaced from the first cog link assembly and includes a series of second engagement surfaces configured to operatively engage the second drive sprocket.

[0006] In another aspect of the disclosure that may be combined with any of these aspects, a passenger conveyor is provided that includes a plurality of pallets defining a longitudinal pallet path, wherein each pallet includes an obverse face, a reverse face, a first lateral side, and a second lateral side. The passenger conveyor further includes a drive assembly including a motor, a first drive sprocket operatively coupled to the motor, and a second drive sprocket operatively coupled to the motor. The drive assembly also includes a first cog link assembly having a series of first engagement surfaces configured to operatively engage the first drive sprocket. The drive assembly further includes a second cog link assembly spaced from the first cog link assembly and having a series of second engagement surfaces configured to operatively engage the second drive sprocket.

[0007] In another aspect of the disclosure that may be combined with any of these aspects, the first and second cog link assemblies are coupled to the plurality of pallets, and in which the first and second drive sprockets are coupled to the truss.

[0008] In another aspect of the disclosure that may be combined with any of these aspects, the first and second cog link assemblies are coupled to a reverse face of the plurality of pallets and the first and second engagement surfaces extend away from the plurality of pallets.

[0009] In another aspect of the disclosure that may be combined with any of these aspects, the first cog link assembly is coupled to a first lateral side of the plurality of pallets, and the second cog link is coupled to a second lateral side of the plurality of pallets.

[0010] In another aspect of the disclosure that may be combined with any of these aspects, the first cog link assembly includes a plurality of first pins defining the first engagement surfaces, and the second cog link assembly includes a plurality of second pins defining the second engagement surfaces.

[0011] In another aspect of the disclosure that may be combined with any of these aspects, the plurality of first pins is aligned along a first engagement path, the plurality of second pins is aligned along a second engagement path, and the first engagement path and second engagement path are substantially parallel to the longitudinal pallet path.

[0012] In another aspect of the disclosure that may be combined with any of these aspects, each of the first and second cog-link assemblies is provided as an integral subassembly that is independently removable from the associated pallet.

[0013] In another aspect of the disclosure that may be combined with any of these aspects, the first drive sprocket defines a first sprocket axis substantially perpendicular to the longitudinal pallet path and the second drive sprocket defines a second sprocket axis substantially perpendicular to the longitudinal pallet path.

[0014] In another aspect of the disclosure that may be combined with any of these aspects, both the first engagement surfaces and the second engagement surfaces are spaced at a pitch distance less than approximately 35 mm.

[0015] In another aspect of the disclosure that may be combined with any of these aspects, a gear drive operatively couples the motor to both the first drive sprocket and the second drive sprocket.

[0016] In another aspect of the disclosure that may be combined with any of these aspects, the gear drive is provided as a spur gear drive including a first spur gear operatively coupled between the motor and the first drive sprocket, and a second spur gear operatively coupled between the first spur gear and the second drive sprocket.

[0017] In another aspect of the disclosure that may be combined with any of these aspects, the gear drive is provided as a bevel gear drive that includes a drive shaft operatively coupled to the motor, a first bevel drive gear coupled to the drive shaft, and a second bevel drive gear coupled to the drive shaft. A first bevel driven gear is coupled to the first drive sprocket and configured to operatively engage the first bevel drive gear, and a second bevel driven gear is coupled to the second drive sprocket and configured to operatively engage the second bevel drive gear.

[0018] In another aspect of the disclosure that may be combined with any of these aspects, the gear drive is provided as a worm gear drive that includes a drive shaft operatively coupled to the motor, a first worm coupled to the drive shaft, a second worm coupled to the drive shaft, a first worm gear coupled to the first drive sprocket and configured to operatively engage the first worm, and a second worm gear coupled to the second drive sprocket and configured to operatively engage the second worm.

Brief Description of the Drawings

[0019] For a more complete understanding of the disclosed methods and apparatuses, reference should be made to the exemplary embodiments illustrated in greater detail on the accompanying drawings, wherein:

[0020] FIG. 1 schematically illustrates a passenger conveyor having portions designed according to the present disclosure.

[0021] FIG. 2 is a side elevation view of a first embodiment of a drive assembly for the passenger conveyor of FIG. 1.

[0022] FIG. 3 is a bottom view of the drive assembly of FIG. 2.

[0023] FIG. 4 is a side elevation view of a second embodiment of a drive assembly for the passenger conveyor of FIG. 1.

[0024] FIG. 5 is a bottom view of the drive assembly of FIG. 4.

[0025] FIG. 6 is a side elevation view of a third embodiment of a drive assembly for the passenger conveyor of FIG. 1.

[0026] FIG. 7 is a bottom view of the drive assembly of FIG. 6. [0027] While the following detailed description has been given and will be provided with respect to certain specific exemplary embodiments, it is to be understood that the scope of the disclosure should not be limited to such embodiments, but that the same are provided simply for enablement and best mode purposes. The breadth and spirit of the present disclosure is broader than the embodiments specifically disclosed and

encompassed within the claims eventually appended hereto, and their equivalents.

Detailed Description of the Disclosure

[0028] FIG. 1 is a simplified schematic representation of a passenger conveyor, which is a moving walkway 20 in this example. The present disclosure, however, is not limited to moving walkways but is applicable to other types of passenger conveyors, such as escalators. The illustrated moving walkway 20 includes a plurality of pallets 22 (shown in greater detail in FIGS. 2-7) that are movable along a loop so that the pallets 22 carry passengers between landings 24, 26. A truss 28 supports the components of the moving walkway 20 in a known manner.

[0029] Two pallet chains 30 are associated with the pallets 22 and are guided by a track system on the truss 28 in a known manner. Each pallet chain 30 includes a plurality of pallet chain links 32 (FIGS. 2-7). The pallet chains 30 may be entrained in direction reversing sprockets or turnaround tracks 34 provided at opposite ends of the loop, thereby to define a longitudinal pallet path 36 along which the pallets 22 travel. The longitudinal pallet path 36 includes an upper passenger section 38, in which the pallets 22 are positioned to support the passengers for travel between landings 24, 26, and a lower return section 40 disposed below the passenger section 38, in which the pallets 22 are returned from the landing 26 to the landing 24 and therefore are generally inaccessible by the passengers.

[0030] An exemplary pallet 22 is shown in greater detail in FIGS. 2 and 3. The pallet 22 defines an obverse face 42 generally configured to support passengers and a reverse face 44 (FIG. 2). The pallet 22 further defines a first lateral side 46, a second lateral side 48, a leading edge 50, and a trailing edge 52 (FIG. 3). Two rods 54, 56 are respectively connected to the first and second lateral sides 46, 48 near the leading edge 50 and are coupled to the pallet chains 30, so that the pallets 22 follow the pallet path 36 defined by the pallet chains 30. A pair of axles 58, 60 is connected to respective lateral sides 46, 48 near the trailing edge 52. Rollers 62, 64 are rotatably coupled to respective axles 58, 60 and engage the truss 28, thereby to support the pallet 22 and any passenger load.

[0031] A drive assembly 70 propels the pallets 22 and the pallet chain 30 along the pallet path 36, thereby to move passengers between the landings 24, 26. In the exemplary embodiment of FIGS. 2 and 3, the drive assembly 70 includes a motor 72 having an output shaft 74 coupled to motor gear 76. A gear drive, such as spur gear drive 80, is operatively coupled to the motor gear 76. The spur gear drive 80 includes a first spur gear 82 and a second spur gear 84. The first spur gear 82 may have outer teeth 86 operatively engaging the motor gear 76 and inner teeth 88 operatively engaging the second spur gear 84.

[0032] The spur gear drive 80 operatively engages sprockets configured to engage each pallet 22. In the illustrated embodiment, a first drive sprocket 90 is coupled to a first sprocket gear 92, which in turn is operatively coupled to the inner teeth 88 of the first spur gear 82. A second drive sprocket 94 is coupled to a second sprocket gear 96, which in turn is operatively coupled to the second spur gear 84. In the exemplary embodiment, the first and second drive sprockets 90, 94 rotate about first and second sprocket axes that are substantially perpendicular to the longitudinal pallet path 36.

[0033] Operation of the motor 72 rotates the first and second drive sprockets 90, 94 in opposite directions. For example, if the motor 72 rotates the motor gear 76 in the clockwise direction as shown in FIG. 3, the first spur gear 82 is driven counter-clockwise and the first sprocket gear 92 and first drive sprocket 90 are rotated clockwise.

Simultaneously, counterclockwise rotation of the first spur gear 82 drives the second spur gear 84 in the clockwise direction and, subsequently, the second sprocket gear 96 and second drive sprocket 94 are driven in the counter-clockwise direction.

[0034] Each pallet 22 includes first and second cog-link assemblies 100, 102 configured for operative coupling to the first and second drive sprockets 90, 94, respectively. As best shown in FIG. 3, the first cog-link assembly 100 is coupled to the reverse face 44 of the pallet and includes a base plate 104 and a series of first engagement surfaces 105 extending away from the reverse face 44. In the illustrated embodiment, the series of first engagement surfaces 105 is provided by a plurality of first pins 106 coupled to the base plate 104. The series of first engagement surfaces 105 may be aligned along a first engagement path 108 that is substantially parallel to the longitudinal pallet path. [0035] While the exemplary embodiment uses the first pins 106 to provide the first engagement surfaces 105, it will be appreciated that other structures, such as arms, pawls, or other elements, may be used for this purpose. Additionally, while each first engagement surface 105 may be provided on a dedicated component, alternatively multiple first engagement surfaces 105 may be formed on a single component, such as a rack formed with a plurality of linear gear teeth.

[0036] Similarly, the second cog-link assembly 102 is coupled to the reverse face 44 of the pallet 22 and includes a base plate 110 and a series of second engagement surfaces 111 extending away from the reverse face 44. In the illustrated embodiment, a plurality of second pins 112 are coupled to the base plate 110 and define the second engagement surfaces 111. The series of second pins 112 may be aligned along a second engagement path 114 that is substantially parallel to the longitudinal pallet path.

[0037] Again, while the exemplary embodiment uses the second pins 112 to provide the second engagement surfaces 111, other structures or elements may be used for this purpose. A single second engagement surface 111 may be formed on a dedicated component, or multiple second engagement surfaces 111 may be formed on a single component, such as a rack. Furthermore, the particular structure(s) used to provide the first engagement surfaces 105 need not be the same as the particular structure(s) used to provide the second engagement surfaces 111.

[0038] In the exemplary embodiment, the series of first pins 106 is disposed adjacent the first lateral side 46 of the pallet 22, while the series of second pins 112 is disposed adjacent the second lateral side 48. The pins 106, 112 are configured to operatively engage the first and second drive sprockets 90, 94, respectively. While in the illustrated embodiment the drive sprockets 90, 94 are positioned to engage the cog-link assemblies 100, 102 as they traverse the passenger section 38 of the pallet path 36, they may alternatively be positioned to engage the assemblies 100, 102 as they traverse the return section 40. The pins 106, 112 of each series may be spaced at a pitch distance that is substantially smaller than the pallet chain pitch of conventional drives. For example, the pitch distance of the pins 106, 112 may be less than approximately 35 millimeters, depending on the size of the drive sprockets 90, 94.

[0039] FIGS. 4 and 5 illustrate an alternative embodiment of a drive assembly 170 for advancing the pallets 22. The only difference from the previous embodiment is the use of a bevel gear drive 180 to operatively connect the motor 72 to the first and second drive sprockets 90, 94. Accordingly, the bevel gear drive 180 may include a drive shaft 182 operatively coupled to the motor 72, such as by a shaft sprocket 184 coupled to a motor sprocket (not shown) by a belt or roller chain (not shown). Any one of the three shaft sprockets 184 illustrated in FIG. 5 may be used to couple to the motor 72. First and second bevel drive gears 186, 188 having opposite orientations may be coupled to the drive shaft 182. A first bevel driven gear 190 is coupled to the first drive sprocket 90 and operatively coupled to the first bevel drive gear 186, while a second bevel driven gear 192 is coupled to the second drive sprocket 94 and operatively coupled to the second bevel drive gear 188. The opposite orientations of the first and second bevel drive gears 186, 188 respectively drive the first and second drive sprockets 90, 94 in opposite directions.

[0040] Yet another embodiment of a drive assembly 270 is illustrated in FIGS. 6 and 7. Again, the only difference from the previous embodiments is the use of a worm gear drive 280 to operatively connect the motor 72 to the first and second drive sprockets 90, 94. Accordingly, the worm gear drive 280 may include a drive shaft 282 operatively coupled to the motor 72, such as by a shaft sprocket 284 coupled to a motor sprocket (not shown) by a belt or roller chain (not shown). Any one of the three shaft sprockets 184 illustrated in FIG. 5 may be used to couple to the motor 72. First and second worms 286, 288 having opposite orientations may be coupled to the drive shaft 282. A first worm gear 290 is coupled to the first drive sprocket 90 and operatively coupled to the first worm 286, while a second worm gear 292 is coupled to the second drive sprocket 94 and operatively coupled to the second worm 288. The opposite orientations of the first and second worms 286, 288 respectively drive the first and second drive sprockets 90, 94 in opposite directions.

[0041] It will be appreciated that multiple alternative arrangements may be used to operatively couple the pallets 22 to the motor 72. In the embodiments disclosed above, the cog-link assemblies 100, 102 are fixed to the reverse face 44 of the pallets 22 and the first and second drive sprockets 90, 94 are coupled to the truss 28 and disposed between the cog-link assemblies 100, 102. In an alternative embodiment illustrated in FIG. 8, the drive sprockets 90, 94 are still supported by the truss 28, but are disposed laterally outwardly from the cog-link assemblies 100, 102. In a further alternative embodiment illustrated in FIG. 9, the cog-link assemblies 100, 102 may be coupled to the truss 28 and the drive sprockets 90, 94 may be coupled to the pallet 22 and disposed between the cog- link assemblies 100, 102. In yet another embodiment illustrated in FIG. 10, the cog-link assemblies 100, 102 may be supported by the truss 28 and the drive sprockets 90, 94 are supported by the pallet 22 but are disposed laterally outwardly from the cog-link assemblies 100, 102. These same configurations may further be used with cog-link assemblies 100, 102 that are coupled to the obverse face 42 of the pallets 22. Still further the cog-link assemblies 100, 102 may be coupled to the first and second lateral sides 46, 48 of each pallet 22 as shown in FIG. 11. The engagement surfaces 105, 11 1 may be oriented vertically as shown in FIG. 11, or may project laterally outwardly from the pallets 22.

[0042] While the embodiments disclosed herein provide a single drive assembly, multiple drive assemblies may be used with a single passenger conveyor. The multiple drive assemblies may be controlled so that a single drive assembly is used during normal loading and that multiple drive assemblies are used during heavy loading.

Industrial Applicability

[0043] In general, the present disclosure sets forth a drive assembly for advancing a pallet assembly of a passenger conveyor. A pair of drive sprockets 90, 94 operatively engages cog-link assemblies 100, 102 coupled to the reverse face 44 of each pallet 22 provided in the passenger conveyor. A gear drive is operatively coupled between the drive sprockets 90, 94 and the motor 72 and configured so that rotation of the motor 72 causes the drive sprockets 90, 94 to rotate in opposite directions. The rotating drive sprockets 90, 94 engage the first and second pins 106, 112 of the cog-link assemblies 100, 102, thereby to advance each pallet 22.

[0044] By virtue of the drive sprockets 90, 94 and gear drive, the present disclosure provides several advantages over traditional drive assemblies used in passenger conveyors. For example, the size and orientation of the drive sprockets 90, 94 allows for a reduced height between the passenger and return sections 38, 40 of the pallet path 36, thereby facilitating installation in areas having limited or no pit space.

[0045] Also, if a cog-link assembly 100, 102 is damaged, it may be removed from the pallet 22 as a unit and replaced independently of the pallet 22, thereby reducing maintenance time and cost.

[0046] In addition, the use of drive sprockets 90, 94 and cog-link assemblies 100, 102 reduces the polygon effect while maintaining a reduced profile. The first and second pins 106, 112 may be spaced by a pitch distance of less than approximately 35 mm. This is significantly smaller than the pallet chain pitch of conventional drives, which typically use pitch distances on the order of 100-200 mm. Accordingly, the drive assembly of the present disclosure may reduce pitch distance by a factor of at least 3 to 5 or more.

Reduction in pitch reduces the polygon effect and the vibration and noise associated therewith. Furthermore, the orientation of the drive sprockets 90, 94 allows for this reduction in polygon effect while still maintaining a small overall height profile for the drive assembly.

[0047] Additionally, no gear box is needed at the motor output, thereby simplifying the connection between the motor and the drive assembly. In the embodiment having the spur gear drive 80 (FIGS. 2 and 3), the motor 72 may be directly connected to the spur gear drive 80 by the motor gear 76. In the embodiments using the bevel gear drive 180 (FIGS. 4 and 5) and the worm gear drive 280 (FIGS. 6 and 7), the motor 72 may be coupled to the gear drive using a chain or belt connection to the drive shaft. In each embodiment, the gear drive has a low height profile, thereby reducing space requirements for the drive assembly. The gear drive may further be configured to provide any necessary gear reduction, thereby eliminating the need for a gear box and facilitating the use of smaller motor sizes.

[0048] Still further, the drive assemblies disclosed herein permit a more flexible location of the motor 72. In the embodiment of FIGS. 2 and 3, the motor 72 may be directly connected to the spur gear drive 80, thereby allowing the motor 72 to be positioned between the passenger and return sections 38, 40 of the pallet path 36.

Alternatively, the motor 72 may be offset from the pallet path 36 in either lateral or longitudinal direction.

[0049] The drive assemblies disclosed herein also automatically align the pallets 22 along the pallet path 36. As noted above, the drive sprockets 90, 94 engage cog-link assemblies 100, 102 that may be coupled to opposite lateral edges of each pallet 22. Accordingly, the drive assemblies advance the opposite lateral edges of each pallet 22 simultaneously, thereby providing a self-alignment feature even if there is pallet misalignment due to track mis-alignment, assembly tolerances, or component clearances.

[0050] Additionally, the drive assembly may further function as a missing pallet detector. If a pallet 22 becomes disengaged, for example, the drive assembly will not engage the cog-link assemblies of the missing pallet and therefore the passenger conveyor will stop. If the drive assembly is configured to engage on the return section 40, then the missing pallet 22 will not be exposed to the passenger section 38, thereby avoiding potential injury to the passengers.

[0051] Furthermore, notwithstanding the fact that the above disclosure has been described with respect to a moving walkway, it will be understood that the drive assembly may be employed with other types of machines and systems that advance a step assembly as well, such as escalators.

[0052] While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure and the appended claims.

Claims

CLAIMS What is claimed is:

1. A drive assembly (70, 170, 270) for a passenger conveyor having a truss (28) and a plurality of pallets (22) defining a longitudinal pallet path (36), the drive assembly (70, 170, 270) comprising:

a motor (72);

a first drive sprocket (90) operatively coupled to the motor (72);

a second drive sprocket (94) operatively coupled to the motor (72);

a first cog link assembly (100) including a series of first engagement surfaces (105) configured to operatively engage the first drive sprocket (90); and

a second cog link assembly (102) spaced from the first cog link assembly (100) and including a series of second engagement surfaces (111) configured to operatively engage the second drive sprocket (94).

2. The drive assembly (70, 170, 270) of claim 1, in which the first and second cog link assemblies (100, 102) are coupled to the plurality of pallets (22), and in which the first and second drive sprockets (90, 94) are coupled to the truss.

3. The drive assembly (70, 170, 270) of claim 2, in which the first and second cog link assemblies (100, 102) are coupled to a reverse face (44) of the plurality of pallets (22) and the first and second engagement surfaces (111) extend away from the plurality of pallets (22).

4. The drive assembly (70, 170, 270) of claim 2, in which the first cog link assembly (100) is coupled to a first lateral side (46) of the plurality of pallets (22), and the second cog link (102) is coupled to a second lateral side (48) of the plurality of pallets (22).

5. The drive assembly (70, 170, 270) of claim 1, in which the first cog link assembly comprises a plurality of first pins (106) defining the first engagement surfaces (105), and in which the second cog link assembly comprises a plurality of second pins (112) defining the second engagement surfaces (111).

6. The drive assembly (70, 170, 270) of claim 5, in which the plurality of first pins (106) is aligned along a first engagement path (108), the plurality of second pins

(112) is aligned along a second engagement path (114), and the first engagement path (108) and second engagement path (114) are substantially parallel to the longitudinal pallet path (36).

7. The drive assembly (70, 170, 270) of claim 1, in which each of the first and second cog-link assemblies (100, 102) is provided as an integral sub-assembly that is independently removable from the associated pallet (22).

8. The drive assembly (70, 170, 270) of claim 1, in which the first drive sprocket (90) defines a first sprocket axis substantially perpendicular to the longitudinal pallet path (36) and the second drive sprocket (94) defines a second sprocket axis substantially perpendicular to the longitudinal pallet path (36).

9. The drive assembly (70, 170, 270) of claim 1, in which both the first engagement surfaces (105) and the second engagement surfaces (111) are spaced at a pitch distance of less than approximately 35 mm.

10. The drive assembly (70, 170, 270) of claim 1, further comprising a gear drive operatively coupling the motor (72) to both the first drive sprocket (90) and the second drive sprocket (94).

11. The drive assembly (70) of claim 10, in which the gear drive comprises a spur gear drive (80) including a first spur gear (82) operatively coupled between the motor (72) and the first drive sprocket (90) and a second spur gear (84) operatively coupled between the first spur gear (82) and the second drive sprocket (94).

12. The drive assembly (170) of claim 10, in which the gear drive comprises a bevel gear drive (180) including:

a drive shaft (182) operatively coupled to the motor (72);

a first bevel drive gear (186) coupled to the drive shaft (182);

a second bevel drive gear (188) coupled to the drive shaft (182);

a first bevel driven gear (190) coupled to the first drive sprocket (90) and configured to operatively engage the first bevel drive gear (186); and

a second bevel driven gear (192) coupled to the second drive sprocket (94) and configured to operatively engage the second bevel drive gear (188).

13. The drive assembly (270) of claim 10, in which the gear drive comprises a worm gear drive (280) including:

a drive shaft (282) operatively coupled to the motor (72);

a first worm (286) coupled to the drive shaft (282);

a second worm (288) coupled to the drive shaft (282);

a first worm gear (290) coupled to the first drive sprocket (90) and configured to operatively engage the first worm (286); and

a second worm gear (292) coupled to the second drive sprocket (94) and configured to operatively engage the second worm (288).

14. A passenger conveyor comprising:

a plurality of pallets (22) defining a longitudinal pallet path (36), each pallet (22) including an obverse face (42), a reverse face (44), a first lateral side (46), and a second lateral side (48);

a drive assembly (70, 170, 270) including:

a motor (72);

a first drive sprocket (90) operatively coupled to the motor (72);

a second drive sprocket (94) operatively coupled to the motor (72);

15. The passenger conveyor of claim 14, in which the first and second cog link assemblies (100, 102) are coupled to the plurality of pallets (22), and in which the first and second drive sprockets (90, 94) are coupled to the truss.

16. The passenger conveyor of claim 15, in which the first and second cog link assemblies (100, 102) are coupled to a reverse face (44) of the plurality of pallets (22) and the first and second engagement surfaces (111) extend away from the plurality of pallets (22).

17. The passenger conveyor of claim 15, in which the first cog link assembly (100) is coupled to a first lateral side (46) of the plurality of pallets (22), and the second cog link (102) is coupled to a second lateral side (48) of the plurality of pallets (22).

18. The passenger conveyor of claim 14, in which the first cog link assembly comprises a plurality of first pins (106) defining the first engagement surfaces (105), and in which the second cog link assembly comprises a plurality of second pins (112) defining the second engagement surfaces (111).

19. The passenger conveyor of claim 18, in which the plurality of first pins (106) is aligned along a first engagement path (108), the plurality of second pins (112) is aligned along a second engagement path (114), and the first engagement path (108) and second engagement path (114) are substantially parallel to the longitudinal pallet path (36).

20. The passenger conveyor of claim 19, in which each of the first and second cog-link assemblies (100, 102) is provided as an integral sub-assembly that is

independently removable from the associated pallet (22).

21. The passenger conveyor of claim 14, in which the first drive sprocket (90) defines a first sprocket axis substantially perpendicular to the longitudinal pallet path (36) and the second drive sprocket (94) defines a second sprocket axis substantially perpendicular to the longitudinal pallet path (36).

22. The passenger conveyor of claim 14, in which both the first engagement surfaces (105) and the second engagement surfaces (111) are spaced at a pitch distance of less than approximately 35 mm.

23. The passenger conveyor of claim 14, further comprising a gear drive operatively coupling the motor (72) to both the first drive sprocket (90) and the second drive sprocket (94).

24. The passenger conveyor of claim 23, in which the gear drive comprises a spur gear drive (80) including a first spur gear (82) operatively coupled between the motor (72) and the first drive sprocket (90) and a second spur gear (84) operatively coupled between the first spur gear (82) and the second drive sprocket (94).

25. The passenger conveyor of claim 23, in which the gear drive comprises a bevel gear drive (180) including: