EP0547737A2

EP0547737A2 - Hydraulic tensioning system in passenger conveyors

Info

Publication number: EP0547737A2
Application number: EP92306886A
Authority: EP
Inventors: Thomas R. Nurnberg; Edward L. Gillet
Original assignee: Montgomery Elevator Co
Current assignee: Montgomery Elevator Co
Priority date: 1991-12-17
Filing date: 1992-07-28
Publication date: 1993-06-23
Also published as: FI925720A; BR9203497A; EP0547737A3; CA2074574A1; JPH0648675A; FI925720A0; TW215071B; KR930012555A

Abstract

A hydraulic tensioning device is disclosed for use in a passenger conveyor which includes a series of passenger platforms supported on and movable along a frame which includes side support tracks for chain driven support rollers mounted on the platforms. A turnaround track assembly is located at an end of the conveyor with track means on each side thereof. The turnaround track assembly is movably mounted relative to the frame and side support tracks. A chain tensioning system is operatively associated between the turnaround track assembly and the frame. The system includes a hydraulic tensioning device interconnected between the turnaround track assembly and the frame on each side of the conveyor. A source of pressurized hydraulic fluid communicates with the tensioning devices. An accumulator hydraulically interconnects the tensioning devices to equalize tensioning between the side of the conveyor.

Description

Field of the Invention

This invention generally relates to the art of passenger conveyors such as escalators or the like, and, particularly, to a hydraulic tensioning system for a turnaround track assembly of a passenger conveyor.

Background of the Invention

A passenger conveyor typically includes a series of passenger platforms or steps which are driven in an endless path between horizontally spaced landings. The passenger conveyor includes a main body frame supported by the floors or other support structures of a building, for instance, and conventionally has track means for the passenger platforms to guide the platforms along a path between the landings. Typically, the track means include a support track for support rollers mounted to the respective passenger platforms, and, in some instances, guide rollers movable along a guide track.
For instance, in an escalator-type passenger conveyor, an endless series of steps are moved from one landing to another to convey passengers. The steps are interconnected by means of a sprocket chain, sometimes called a running gear chain. Usually, such a chain is used on each side of the escalator. In addition, each step is provided with at least one support roller on each side thereof, associated with the running gear chain, along with a trailer roller. Guide means are provided at each end of the escalator for guiding the rollers around the bends of the endless conveyor means. The guide means usually are provided in the form of a turnaround track assembly. The track assembly includes pairs of inner and outer curved tracks for the support rollers and the trailer rollers to rotate around the bends at the ends of the escalator.
It is typical in escalator-type passenger conveyors to provide a chain tensioning system at one end of the conveyor system, such as beneath the lower landing. These tensioning systems sometimes are termed "step band tensioning systems". Heretofore, a typical escalator step band tensioning system included a compression spring mechanism on each side of the conveyor or operatively associated with each side chain. The tensioning typically was mechanical in nature, such as with a threaded rod associated with the compression spring. In order to equalize tension on opposite sides of the conveyor, i.e., to equalize the respective tensions on the side chains, tape or ruler measurements were used to estimate the tension setting. Such settings actually are approximate, at best, and are susceptible to certain variances, such as different compression spring rates, and are susceptible to other misadjustments due to wear as well as maintenance human error.
This invention is directed to providing a hydraulic tensioning system designed to automatically equalize the chain tension on opposite sides of the conveyor or escalator.

Summary of the Invention

An object, therefore, of the invention is to provide a new and improved tensioning system for a turnaround track assembly of a passenger conveyor.
As disclosed herein, a passenger conveyor is illustrated in the form of an escalator which includes a series of steps or passenger platforms supported on and movable along a frame which includes side support tracks for chain driven support rollers mounted on the platforms. A turnaround track assembly is located at an end of the conveyor, with track means on each side of the moving platforms. The turnaround track assembly is movably mounted relative to the frame and side support tracks.
The invention contemplates a chain tensioning system operatively associated between the turnaround track assembly and the frame. The tensioning system includes a hydraulic tensioning device interconnected between the turnaround track assembly and the frame on each side thereof. A source of pressurized hydraulic fluid communicates with the tensioning devices. Means are provided for hydraulically interconnecting the tensioning devices to equalize tensioning between the sides of the turnaround track assembly.
As disclosed herein, the source of pressurized hydraulic fluid is hydraulically connected to an accumulator which, in turn, is hydraulically connected to the side hydraulic tensioning devices, thereby equalizing the pressure therebetween. In the preferred embodiment, the hydraulic tensioning devices comprise piston and cylinder devices.
In the illustrated embodiment of the invention, the hydraulic devices are interconnected between push members fixed to the frame and slide members movably mounted on the frame and fixed to the turnaround track assembly. The slide members are provided in the form of slider plates having opposite edges supported by roller means.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.

Brief Description Of The Drawings

The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which like reference numerals identify like elements in the figures and in which:

FIGURE 1 is a somewhat schematic illustration of a typical escalator construction, with the hydraulic tensioning system of the invention located at the lower left-hand corner of the illustration, below the lower landing;
FIGURE 2 is another schematic illustration, on an enlarged scale, showing the location of the hydraulic tensioning system of the invention, and particularly the turnaround track assembly in association with the rollers of an escalator step;
FIGURE 3 is an elevational view, on a further enlarged scale, of the hydraulic tensioning system at one side of the escalator;
FIGURE 4 is an end elevational view of the hydraulic tensioning system; and
FIGURE 5 is a fragmented end elevational view, on an enlarged scale, of the right-hand side of the system shown in Figure 4.

Detailed Description of the Preferred Embodiment

Referring to the drawings in greater detail, and first to Figure 1, a general arrangement of a passenger conveyor in the form of a typical escalator, generally designated 10, is shown. The arrangement includes a stationary main frame, schematically illustrated at 12, which mounts the conveyor to a support structure of a building, for instance. The main frame supports a pair of horizontally spaced circuitous handrails 18. The passenger platforms are supported by a plurality of support rollers movable on a support track, as described in greater detail hereinafter. Suffice it to say, circles 20 in Figure 1 simply are shown to illustrate some of the support rollers. the support track is appropriately fixed to stationary frame 12.
Chains 14 are moved by a conventional belt drive, generally designated 22, to continuously move passenger platforms 16 in a closed-loop path between a front or lower landing 24 and an upper landing 26. A second belt drive mechanism, generally designated 28, drives handrail 18 in a closed-loop path in synchronism with the endless series of a passenger platforms 16, as indicated by arrows 30, as a passenger stands on one of the platforms and grasps handrail 18.
It should be understood that the illustration of escalator 10 in Figure 1, along with the above description thereof, is somewhat schematic in that the described components of the escalator are generally conventional. It must be understood that the invention is directed to a tensioning system for use with passenger conveyors in general, including escalators, as described, as well as horizontal moving walkways and the like.
Referring to the bottom, left-hand corner of Figure 1, a turnaround track assembly, generally designated 32, is shown schematically below lower landing 24. As will be described in greater detail below, the turnaround track assembly is movably mounted for movement in the direction of double-headed arrow 34 in order to adjust the tension in chains 14 which move passenger platforms or steps 16 in their circuitous paths.
Figure 2 shows an enlarged schematic depiction of the bottom left-hand corner of Figure 1 to illustrate turnaround track assembly 32 in conjunction with a step 16 which has a pair of front support rollers 36 and a trailer support roller 38, as the step moves in the direction of arrow 40. Only one step is shown in Figure 2 to avoid cluttering the illustration. Each side of turnaround track assembly 32 includes a pair of outer tracks 42 and 44 between which support rollers 36 move. The tracks are generally semi-circular whereby, on the upper run of the tracks, inner track 42 support rollers 36 and outer track 44 provides a hold-down means for the rollers. A second pair of generally semi-circular tracks 46 and 48 are provided for guiding trailer roller 38 around the turnaround area. Again, in the upper run of the tracks, inner track 46 supports trailer roller 38 and outer track 48 provides a hold-down means for the trailer roller. Of course, on the lower runs of the pairs of tracks, the support and hold-down functions of the tracks are reversed.
Referring to Figure 3 in conjunction with Figure 1, turnaround track assembly 32 is shown in greater detail, including the above-described tracks 42, 44 and 46, 48 on each side of the conveyor. It should be understood that the more detailed depiction of Figure 3 shows only one side of the turnaround track assembly, such as looking inside-out at the left side of the conveyor when facing inwardly toward the lower landing. The opposite or right side is identical. Consequently, the numeral 32a is being used for the subassembly shown in Figure 3. Tracks 42, 44, 46, 48 are mounted on a common or base support plate 50 which is shown to have a generally semi-circular outer periphery 52. The guide track means on main frame 12 (Fig. 3) are similarly constructed to include an inner support track 54 and an outer hold-down track 56 for step support rollers 36, and an inner support track 58 and an outer hold-down track 60 for trailer rollers 38. Still referring to Figure 3, as stated above, turnaround track assembly 32 (therefore, subassembly 32a) is mounted for movement in the direction of double-headed arrow 34 relative to main frame 12 and tracks 54-60.
The movable mounting of each subassembly 32a, on each side of the conveyor, is provided by a slider plate 62 fixed by appropriate fastening means 64 to base support plate 50 of turnaround track subassemhly 32a. A second plate 66 is fixed by appropriate fastening means 68 to base support plate 50, on the outside of the base support plate, to provide further rigidity for slider plate 62. The slider plate extends beyond an inner edge 70 of base support plate 50 and is disposed between three top rollers 72 and three bottom rollers 74 journalled on stationary main frame 12. Therefore, slider plate 62 is movable between rollers 72 and 74 in the direction of double-headed arrow 76 to move turnaround track subassembly 32a therewith in the direction of double-headed arrow 34. A push block in the form of an angle beam 78 is fixed to stationary main frame 12 by bolts or other appropriate fastening means 80. The push block overlies and is spaced from the inside of the slider plate 62.
As stated above, Figure 3 is a depiction looking "inside-out" at one side of the escalator below landing 24. Therefore, it should be understood that one of the turnaround track subassemblies 32a, slider plates 62, rollers 72 and 74, and push blocks 78 are provided at each side of the escalator or conveyor system.
The invention contemplates a hydraulic chain tensioning system operatively associated between the turnaround track subassemblies 32a and the stationary main frame 12 on each side of the escalator system to equalize tension on the step chains on opposite sides of the conveyor. Still referring to Figure 3, a hydraulic tensioning device in the form of a piston and cylinder device, generally designated 82, is interconnected between each turnaround track subassembly 32a and stationary main frame 12 on each side of the escalator. Each tensioning device includes a cylinder 84 mounted by brackets 86 to slider plate 62. A piston 88 projects from the inner end of cylinder 84 and is engageable with push block 78 fixed to stationary main frame 12. Therefore, upon application of pressurized fluid to cylinder 84, piston 88 will move in the direction of arrow 90 against push block 78 which, in turn, moves turnaround track subassembly 32a away from the main frame.
Figure 4 shows an end view of the hydraulic tensioning system to illustrate that a hydraulic piston and cylinder device 82 is located at each opposite side of the escalator, along with the respective slider plates 62, rollers 72 and 74, base support plates 50 and support plates 66. In addition, rollers 72 and 74 can be seen to be journalled on bolt like stub shafts 92.
As stated above, the invention contemplates that hydraulic piston and cylinder devices 82 be hydraulically connected to equalize tensioning on the step chains between the turnaround track subassemblies at opposite sides of the escalator or conveyor. More particularly, still referring to Figure 4, each cylinder of each piston and cylinder device communicates hydraulically through conduits 96 to a common accumulator 98 which, in turn, communicates through a conduit 100 to a source 102 of pressurized hydraulic fluid. Therefore, the pressure in the cylinders are maintained equal, whereby the forces of the pistons on push blocks 78 likewise are equal. The piston and cylinder devices, themselves, should be mounted to be substantially parallel to each other, i.e. in a common plane, to assure precise applications of equal forces on push blocks 78.
Accumulator 98 provides both a reservoir and pressure or tension regulation. Tension on the step chains is adjusted by controlling the accumulator charge pressure. The accumulator charge can be monitored by an appropriate pressure gauge 106 for easy visual observation. Of course, accumulator charge monitoring could be accomplished by appropriate electronic controls of the escalator by means of a pressure transducer or a switch. With such a hydraulic system, emergency shutdown could be triggered either by a loss of pressure (i.e., chain tension), pressure fluctuation, flow detection or any combination thereof, such as resulting from an obstruction or impact to the turnaround track subassemblies or other abnormal operating conditions. Cushioning or shock absorption also is possible with the use of simple orifices or flow control valves operatively associated with the hydraulic devices. All of these advantages are afforded by the hydraulic tensioning system of the invention, which otherwise would be impossible or impractical with mechanical tensioning systems heretofore available.
It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Claims

1. In a passenger conveyor which includes a series of passenger platforms supported on and movable along a frame which includes side support tracks for chain driven support rollers mounted on the platforms, and including a turnaround track assembly at an end of the conveyor with track means on each side thereof, the turnaround track assembly being movably mounted relative to the frame and side support tracks, a chain tensioning system operatively associated between the turnaround track assembly and the frame, comprising a hydraulic tensioning device interconnected between the turnaround track assembly and the frame on each side of the conveyor, a source of pressurized hydraulic fluid communicating with the tensioning devices, and means for hydraulically interconnecting the tensioning devices to equalize tensioning between the sides of the conveyor.

2. In a passenger conveyor as set forth in claims 1, wherein said hydraulic tensioning devices comprise piston and cylinder devices.

3. In a passenger conveyor as set forth in claim 1, wherein said hydraulic tensioning devices are interconnected between fixed means on the frame and means movably mounted on the frame, the movably mounted means supporting the turnaround track assembly.

4. In a passenger conveyor as set forth in claim 1, including a push member fixed to the frame, a slide member movably mounted on the frame and fixed to the turnaround track assembly, and at least one of said tensioning devices interconnected between the push member and the slide member.

5. In a passenger conveyor as set forth in claim 4, wherein said slide member is movably mounted on roller means journalled on the frame.

6. In a passenger conveyor as set forth in claim 5, wherein said slide member comprises a slider plate, and said roller means are mounted along opposite edges of the slider plate.

7. In a passenger conveyor as set forth in claim 1, wherein said hydraulic tensioning devices are hydraulically interconnected to a common accumulator to equalize pressure to the tensioning devices.

8. In a passenger conveyor as set forth in claim 7, wherein said source of pressurized hydraulic fluid is hydraulically connected to the accumulator.

9. In a passenger conveyor which includes a series of passenger platforms supported on and movable along a frame which includes side support tracks for chain driven support rollers mounted on the platforms, and including a turnaround track assembly at an end of the conveyor with track means on each side thereof, the turnaround track assembly being movably mounted relative to the frame and side support tracks, a chain tensioning system operatively associated between the turnaround track assembly and the frame, comprising a hydraulic piston and cylinder device interconnected between the turnaround track assembly and the frame on each side of the conveyor, the piston and cylinder devices being generally parallel, a source of pressurized hydraulic fluid communicating with the piston and cylinder devices, and accumulator means for hydraulically interconnecting the piston and cylinder devices to equalize tensioning between the sides of the conveyor.

10. In a passenger conveyor as set forth in claim 9, wherein said source of pressurized hydraulic fluid is hydraulically connected to the accumulator means.

11. In a passenger conveyor as set forth in claim 9, wherein said piston and cylinder devices are interconnected between respective push members fixed to the frame and slide members movably mounted on the frame and fixed to the turnaround track assembly.

12. In a passenger conveyor as set forth in claim 11, wherein said slide members comprise slider plates having opposite edges thereof movably mounted between roller means journalled on the frame.

13. In a passenger conveyor which includes a series of passenger platforms supported on and movable along a frame by chain driven support rollers mounted on the platforms, and including a turnaround assembly at an end of the conveyor, the turnaround assembly being movably mounted relative to the frame, a chain tensioning system operatively associated between the turnaround assembly and the frame, comprising a hydraulic device interconnected between the turnaround track assembly and the frame on each side of the conveyor, the hydraulic tensioning devices being hydraulically interconnected to equalize tension between the sides of the conveyor.

14. In a passenger conveyor as set forth in claim 13, wherein said hydraulic tensioning devices comprise piston and cylinder devices.

15. In a passenger conveyor as set forth in claim 13, wherein said piston and cylinder devices are hydraulically interconnected to a common accumulator to equalize pressure between the devices.