Pedestrian conveyor mass damper for reducing step vibrations

Abstract

A pedestrian conveyor includes a torsional vibration damper system including a shaft, a cylindrical housing attached to the shaft and configured to damp vibrations of the shaft, a first gear, and a second gear.

Description

Technical Field

[0001] The present invention provides a solution to low frequency step oscillations using a tuned mass damper for reducing the polygon effect that occurs in pedestrian conveyors including escalators or moving walkways. The damper is connected to the pedestrian conveyor through gears using a step up gearbox. The use of a gearbox greatly reduces the mass required to make the tuned mass damper effective. Background Art

[0002] Some escalator steps may vibrate at a low frequency and feel very uncomfortable. Almost all escalator steps are driven by a sprocket system. Although this method of power transmission has several advantages in terms of reliability, the interaction of the step chain roller with the sprocket will never be completely smooth and will have an excitation amplitude frequency known as the polygon effect. Specifically, the linear speed of the chain of the sprocket system is not uniform, but varies during each cycle of its engagement with the teeth of the driven sprocket. This causes pulsation (jitter) in the chain and driven sprocket. This polygon effect depends on the number of teeth on the sprocket. When the number of teeth on the sprocket is less than 20, a pulsating motion will be emitted. To obtain a large number of teeth on the sprocket, it is necessary to increase the size of the sprocket, which is impractical on escalators due to limited space.

[0003] The step-link belt is relatively elastic and therefore has multiple natural frequencies within this polygon effect frequency range. This means that, in some cases, the dynamics of the step-link belt can amplify the excitation caused by the polygon effect.

[0004] Conventional methods of addressing the polygon effect involve reducing the excitation by optimizing the sprocket teeth and guiding the chain onto the rails.

[0005] For example, Pietz (U.S. Pat. No. 6892874B2) discloses a solution for actively eliminating excitation by superimposing a different rotation speed on the rotation speed of the reversing wheel through an electric drive, which acts on the reversing wheel indirectly or directly. However, the electric drive of Pietz is a direct drive system, and the method disclosed therein is not applicable to chain drive systems.

[0006] Other approaches include control of the step-chain belt dynamics, including making the chain stiffer to increase the natural frequency, or adding mass to the chain to reduce the frequency. Summary of the invention

[0007] The mass damper system of the present invention is coupled to the rotating or translating components of a pedestrian conveyor through gears to dampen vibration / excitation forces to reduce the pulsating motion inherent in the chain driven system, thereby providing smooth operation of the conveyor system.

[0008] The mass damper system of the present invention can be used as a step-up gearbox by having multiple gears, each gear can be sized to generally reduce the need for large masses, thereby reducing the size of the mass damper system. This reduced size can allow retrofitting into any type of existing pedestrian conveyor system.

[0009] The mass damper system of the present invention works by adding a rotational tuned mass damper to counteract the translational vibrations of the step by counteracting the torsional oscillations produced by the entire system. The present invention involves adding a rotational tuned mass damper applied to a rotating gear / sprocket or a translating chain of a pedestrian conveyor system.

[0010] The tuned mass damper of the present invention is designed to absorb vibrations to transfer at least part of the energy from the passenger step to the oscillating mass damper. However, the mass damper of the present invention may be designed to absorb substantially all vibrations generated during operation of the pedestrian conveyor.

[0011] The present invention is a completely passive system that requires no electrical connection to the pedestrian conveyor controller and damps the pulsations inherent in pedestrian conveyor systems, including damping rotational and torsional vibrations.

[0012] Furthermore, the invention is inexpensive to produce and implement, since it can be integrated onto any chain or gear of a known pedestrian conveyor system by combining the mass of the tuned mass damper with the system mass.

[0013] The torsional mass damper system may include any known type of mass damper, such as a viscous damper (e.g., a harmonic balancer) or a friction member based mass damper. A friction member based mass damper is also known as a torsional vibration damper and is typically provided with a plurality of circumferentially spaced weights and a friction member that engages with a housing or another component when exposed to vibration or other forces. The torsional mass damper system of the present invention may be attached to a shaft or any other component of a pedestrian conveyor to reduce or eliminate pulsations by providing resistance to pulsations due to torsion or translation.

[0014] Finally, the present invention can be retrofitted to any existing pedestrian conveyor, including any escalator or moving walkway, to reduce pulsations due to twisting or translation.

[0015] Further scope of application of the present invention will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, although indicating embodiments of the present invention, are given by way of illustration only, because various changes and modifications within the scope of the present invention will become apparent to those skilled in the art from the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A more complete understanding of the present invention will be obtained through the following detailed description and accompanying drawings, which are provided for illustrative purposes only and therefore do not constitute a limitation of the present invention, wherein:

[0017] Figure 1 shows a cross-sectional view of a tuned mass damper according to the present invention;

[0018] Figure 2 A perspective view showing a mass damper system of the present application is shown;

[0019] Figure 3 shows a perspective view of the interior of the counterweight including the spring plate and shaft;

[0020] Figure 4 shows a side cross-sectional view of a mass damper system disposed within a pedestrian conveyor truss frame;

[0021] Figure 5 shows a top perspective view of a mass damper system of the present invention installed within a step belt of a pedestrian conveyor and at a conveyor return station;

[0022] Figure 6 shows a perspective view of a mass damper system with a counterweight extending outside of a pedestrian conveyor truss frame;

[0023] Figure 7 A perspective view of a mass damper system is shown, wherein a counterweight plate is provided at the Figure 6 The mass damper system extends to the exterior of the pedestrian conveyor truss frame at various locations;

[0024] Figure 8 shows a perspective view of retrofitting the mass damper system of the present invention into an existing pedestrian conveyor, including the steps of attaching brackets, shafts, and end plates;

[0025] Fig. 9 Shown in Figure 8 The steps performed after the step of comprising attaching the spring plate to the shaft;

[0026] Fig.10 Shown in Fig. 9 The steps performed after the step of comprising attaching a weight to the spring plate, the shaft and the end plate; and

[0027] Fig.11A and 11B is a diagrammatic representation of an alternative mass damper system 50 of the present invention. DETAILED DESCRIPTION

[0028] The present invention will now be described with reference to the drawings, wherein like reference numerals are used to identify the same or similar elements throughout the several views.

[0029] Figure 1 A non-limiting embodiment of a torsional tuned mass damper 1 of the present invention is shown, which may be applied to pedestrian conveyors including escalators or moving walkways. Figure 1 The mass damper system of shows a rotating shaft 5, which is attached to a plurality of leaf springs / spring plates 9, and to a drum / counterweights 11 that rotates during operation of the pedestrian conveyor. The spring plates 9 may comprise spring steel to provide torsional resilience.

[0030] Figure 2 A perspective view of the mass damper system of the present application is shown. Figure 2 A mass damper system 1 is shown, which comprises a shaft 5, a plurality of spring plates 9 (also shown in FIG. Figure 3 ), a plurality of counterweights 11. Each counterweight 11 is disposed on and attached to at least one corresponding one of the plurality of spring plates 9. An end plate 13 is connected to the ends of the outermost pair of counterweights 11, and a gear 17 (which may be any known gear) is disposed on one or both ends of the shaft 5 and includes at least one gear 19. Other gears may be provided.

[0031] The gear 17 is fixed in place and is connected to the shaft 5 by a fastening member 18 that engages with the keyway 5a of the shaft 5. The fastening member 18 can be a key. In addition, one or more brackets 20 are provided, each of which can include a bearing 16. The shaft 5 engages each bearing 16, and the bearing 16 rotates relative to the shaft 5 and fixes the shaft 5 in place. The bracket 20 can be fixed to the corresponding hub 46 by a fastener 20a. The mass damper system 1 can be provided with two hubs 46 and two gears 17, or can be provided with any number of hubs and gears instead. In addition, the mass damper system 1 can be set at any position on the pedestrian conveyor, so that the bracket 20 can be attached to any position along the pedestrian conveyor and can be fixed by any known fastening means, such as screws, bolts, brazing, welding, etc.

[0032] The bracket 20 is attached to the corresponding hub 46 by a plurality of fasteners 20a. Specifically, the bracket 20 is connected to the corresponding hub 46 at its first end and includes a bearing 16 at its second end. In addition, the shaft 47 is disposed between the two pedestrian conveyor sprockets 45 and is fitted into the corresponding hub 46.

[0033] Furthermore, the first end of each bracket 20 includes a curved shape for receiving the shaft 47. The curved shape may be generally "U" shaped, or may have any shape that allows the bracket 20 to be connected to the corresponding hub 46.

[0034] In addition, each gear 19 may be connected to the corresponding pedestrian conveyor sprocket 45 via a plurality of bent plates 19a. Specifically, each fastening member 19b is provided through a corresponding hole of the corresponding gear 19 and is attached to the corresponding plate 19a via a threaded connection or the like to fix the gear 19 to the front side of the corresponding conveyor sprocket 45. Each plate 19a at least contacts the rear side of the corresponding conveyor sprocket 45 when connected with the fastening member 19b, and the rear side of the corresponding conveyor sprocket 45 is opposite to the front side of the corresponding conveyor sprocket 45. In addition, each plate 19a may include two flange portions that contact the rear side of the corresponding conveyor sprocket 45. As shown in FIG. Figure 2 As shown, the two flange portions allow each gear 19 to be fixed to a corresponding conveyor sprocket 45. A plurality of fastening members 19b can be used, including two fastening members 19b, for each hole 45b of a corresponding conveyor sprocket 45. In addition, each plate 19a can include a body portion that includes a threaded hole for receiving a corresponding fastening member 19b. The threaded hole can be substantially disposed in the center of the body portion and in the center of each plate 19a, however, the threaded hole can be disposed along any portion of the fastening member 19b.

[0035] End plates 13 are provided on both sides of the plurality of counterweights 11, and a plurality of fasteners 12 are provided to attach the end plates 13 to the counterweights 11 and to attach the end plates 13 to each other. Each fastener 12 extends through a corresponding hole of a corresponding counterweight 11 in a pair of counterweights 11 to fix / adjoin the counterweights 11 to each other in the longitudinal direction of the shaft 5.

[0036] The fastener 12 attached to the counterweight 11 and the end plate may be a screw having a bolt head at one end and a threaded portion at the other end, and may also include a nut engaged with the threaded portion. However, any known fastener / fastener combination may be used to engage the plurality of counterweights 11 and the end plates 13 with each other. For example, four screws may be used, and the screws may be equally spaced around a circular path defined by a pair of circular adjacent plates. However, any number of fasteners may be used.

[0037] The end plates 13 are configured to rotate / oscillate by the operation of the pedestrian conveyor, and they are not fixed to the keyway 5a of the shaft 5. Furthermore, the end plates 13 may oscillate during the operation of the pedestrian conveyor.

[0038] The gear 17 of the mass damper system 1 can be engaged with the gear 19. The gear 19 rotates with the sprocket, which directly drives the step chain 21, such as Figure 4 as shown, or driving any other known gear in a pedestrian conveyor system.

[0039] The gears 17 of the mass damper system 1 can be sized to reduce the amount, size and number of counterweights required to damp the pulsation / vibration forces of the pedestrian conveyor to a predetermined level. For example, a smaller gear 17 that increases the gear ratio can be used to reduce the amount, size and number of counterweights.

[0040] The gear 17 of the mass damper system 1 interacts with the gear 19, which is directly connected to the sprocket 45 of the pedestrian conveyor. In other words, the gear 19 is excited and / or vibrates during operation of the pedestrian conveyor through its connection with the sprocket 45 of the pedestrian conveyor, and the mass damper system 1 of the present application damps this vibration, which generates impulses due to the polygon effect, as described above. Alternatively, the gear 17 of the mass damper system can directly engage the step chain 21, such as Figure 7 shown. Figure 2 A pair of gears 17 and a pair of gears 19 are shown, however, a single gear 19 and a single gear 17 may also be used, such as Figure 6 and 7 shown.

[0041] The gears 17 and 19, the counterweight 11, the shaft 5 and the bracket 20 may comprise any known material, preferably, they comprise a metal material.

[0042] Figure 3 A perspective view of the interior of the counterweight 11 is shown, including the spring plate 9 and the shaft 5. Figure 3 As shown, the shaft 5 is provided with a keyway 5a extending over its entire length (ie along its longitudinal axis) for attaching the spring plate 9 thereto via a corresponding flange member 7 and for attaching the gear 17 to the shaft via a key 18 to ensure that the gear 17 rotates without constraint.

[0043] The spring plates 9 are configured to absorb rotational vibration forces by rotating in response to a load (i.e., the operation of the pedestrian conveyor). In other words, the spring plates 9 are sized so that they have a natural frequency similar to the pulse frequency, so they resonate with the counterweight attached thereto and provide resistance to the pulses of the conveyor. Each spring plate 9 is attached to the keyway 5a of the shaft 5 via a flange 7 and a fastener 8. Multiple pairs of flanges 7 can be used to attach each spring plate 9 to the shaft 5. The first flange 7a in each pair of flanges 7 has an internal shape corresponding to the shape of the keyway 5a and is disposed in the keyway 5a to connect the flange 7 to the shaft 5. In addition, the second flange 7b in the pair of flanges 7 can be fixed to the first flange 7a by a fastener 8 to lock / fix the pair of flanges 7 relative to the shaft 5. The fastener 8 can be a bolt, a screw, or any known fastener.

[0044] Each of the plurality of counterweights 11 may be in the form of a semicircular plate. The counterweights 11 may be arranged in pairs on the shaft 5 in a radial plane of the shaft 5, and the paired counterweights 11 may abut against an adjacent pair of counterweights along the longitudinal direction of the shaft to form a stack of the counterweights 11. The paired counterweights 11 may be symmetrical about the central axis of the shaft 5 in the radial direction of the shaft 5.

[0045] Each counterweight 11 may be formed in a C-shape, the end / end face of the C-shape being attached to the corresponding end / end face of the adjacent counterweight 11 at the corresponding radial position to form a pair of counterweights 11 having a circular shape, as shown in the figure. However, any shape of counterweight 11 may be used. Preferably, the counterweight is symmetrical about the central axis of the shaft. Each end face may include a flat surface to flush against the corresponding end face of the adjacent counterweight 11. In addition, each counterweight 11 may be provided with a flange 11a at its end face to connect the counterweight 11 to the corresponding spring plate 9 and the flange 11a of the adjacent counterweight 11 to form a fixed pair of counterweights. The end of each counterweight 11 may be attached to the corresponding spring plate 9 through the hole 10 of the spring plate 9. For example, the spring plate 9 may be provided with a hole / slot 10 for accommodating a fastener 15 extending from the flange 11a of one counterweight 11 through the corresponding spring plate 9 and reaching the other counterweight 11 to fix two adjacent counterweights 11 and the spring plate 9 to each other. Figure 3 Four spring plates 9 and eight (8) pairs of adjacent counterweights 11 are shown. However, there may be any number of counterweights 11 and spring plates 9.

[0046] Figure 4 The truss frame 30 (see also FIG. Figure 5 ) shows the interaction between the chain belt 21 (which may be a step chain belt 19), the gear 19 and the mass damper system gear 17. The gear 19 is fixed to the sprocket 45 by a bracket 19a and a corresponding fastener 19b, which extends through a hole in the gear 19 and is fixed to a threaded hole in the bracket 19a. The step chain belt includes a plurality of rollers 25 and a plurality of chain guides 23.

[0047] Each gear wheel 19 is connected to the pedestrian conveyor sprocket 45 via a plurality of brackets 19a and respective fastening elements 19b.

[0048] Figure 5 The present invention is installed in the escalator truss frame 30. Figure 2 1, wherein the mass damper system 1 is located at the return station 40 of the steps of the pedestrian conveyor. The bracket 20 of the mass damper system 1 is attached to the return station 40 of the pedestrian conveyor by fasteners.

[0049] Figure 6 and 7A perspective view of the mass damper system 1 is shown, wherein the counterweight 11 extends outside the escalator truss frame 30. Figure 6 In the embodiment, the gear 19 of the mass damper system 1 can be directly engaged with the step chain 21 or can be engaged with any gear (including the step chain gear) or with the sprocket 45. Figure 6 and 7 As shown, the counterweight 11 can be mounted on the outside of the conveyor truss frame 30 and can be driven independently without connecting the left and right sides at any location on the left and right sides. The frame 30 can be any known frame type used in pedestrian conveyors. In addition, the ladder chain 21 can directly drive the steps 35 of the pedestrian conveyor. Figure 7 A mass damper system 1 is shown which is arranged along a pedestrian conveyor at a position corresponding to Figure 6 In particular, the mass damper system 1 may be disposed at an incline of the pedestrian conveyor, rather than at a horizontal area near the return station 40, or may be disposed at any other location. For a moving sidewalk or the like, the mass damper system 1 may be disposed at any location along the moving sidewalk. For illustration purposes, the gear 17 is shown as being spaced apart from the step chain 21, however, it may be directly engaged with the step chain 21 through other gears that engage with the step chain 21.

[0050] In addition, multiple mass damper systems 1 can be provided on the exterior of the conveyor truss frame 30 at multiple locations throughout the pedestrian conveyor system. The multiple locations can be determined based on an analysis of the operational vibrations of the pedestrian conveyor at different speeds. For a given operating speed and a given operating load, each mass damper system can be installed at a location at or near an area where the vibration is greater than a predetermined vibration. The operating speed is the speed of the pedestrian conveyor during its use, and the operating load is the load applied to the pedestrian conveyor during its use.

[0051] The mass damper system of the present invention can be connected to any location on the pedestrian conveyor and can be connected directly to the step chain belt or can be connected to the step belt sprocket, or to any other gear of the pedestrian conveyor. When the mass damper is installed, the mass damper system can include a counterweight in the middle of the pedestrian conveyor, and the shaft can be driven by gears on the sprockets on both sides of the counterweight, such as Figure 2 and 5 shown.

[0052] The use of gears 19 and 17 (i.e., a gearbox) can greatly reduce the required size and weight of the tuned mass damper by amplifying the effective inertia of the mass damper as the square of the step-up ratio. Preferably, the effective mass of the tuned mass damper must be 2-5% of the mechanical mass in order to effectively damp. In this case, if a stepped chain with multiple tones is to be damped, a gear ratio of, for example, six (6) will reduce the required mass by a factor of 36.

[0053] The mass damper system 1 of the present invention can be retrofitted to any known pedestrian conveyor by coupling the sprocket of the mass damper system to any gear or directly to a step chain. In addition, multiple mass damper systems 1 can be applied to pedestrian conveyors. Retrofit methods include using vibration analysis tools, which may include PMT TM The EVA-625 elevator vibration analysis system, while the pedestrian conveyor system is operating, measures the vibration of the entire pedestrian conveyor system at different fixed speeds. If the vibration level exceeds a predetermined amount, the mass damper system described above can be added to any location of the pedestrian conveyor system, including locations where the vibration level is greater than the predetermined amount.

[0054] Furthermore, the number and location of the counterweights can be determined based on the locations with the maximum vibration levels, and the size of the gears 19 and 17 of the mass damper system 1 can be determined accordingly to reduce the size and number of the counterweights 11 for a given application. In particular, due to space limitations of existing pedestrian conveyor systems, the size of the sprockets can be determined accordingly to allow for a reduction in the size and / or weight of the counterweights used.

[0055] The method of the present invention for retrofitting a mass damper system comprises: Figure 2 The bracket 20 shown in the figure is used to mount the shaft 5 to the existing pedestrian conveyor structure. The shaft 5 extends through the bearing 16 of each of the one or more brackets 20, and the end plate 13 is disposed on the shaft 5, as described above. The bracket 20 is fixed to the components of the pedestrian conveyor system by any known fastener system. For example, the bracket 20 can be mounted to the return station 40 of the pedestrian conveyor, such as Figure 8 As shown, the return station 40 includes a sprocket 45 engaged with the step chain 21 of the pedestrian conveyor. In addition, the shaft 5 may include Figure 2 The gear 17 shown is engaged with the gear 19, and the gear 19 can be engaged with the gear 45 of the return station 40. Figure 8 In the embodiment, only the shaft 47 is omitted to emphasize the connection between the end plates 13, however, the return station 40 is provided with a shaft 47 extending between two shaft hubs 46, as shown in FIG. Figure 2 shown.

[0056] The end plates 13 are connected to each other by a plurality of fasteners 12, and gaps defined by the fasteners 12 are provided between the end plates 13 to allow insertion of the spring plate 9 and the counterweight 11. The fasteners 12 may include a plurality of screws fixed to each end plate by nuts, however, any known fasteners may be used.

[0057] Fig. 9 The steps of attaching the spring plate 9 to the shaft 5 are shown, and one end plate 13 is omitted for illustration purposes. Each spring plate 9 is attached to the keyway 5a of the shaft 5 by means of a flange 7 and a fastener 8 (see Figure 3 ). Each spring plate 9 may be attached to the shaft 5 using a plurality of pairs of flanges 7, wherein a first flange 7a in each pair of flanges 7 has an inner shape corresponding to the shape of a keyway 5a and is disposed in the keyway 5a to connect the flange 7 to the shaft 5. In addition, a second flange 7b in the pair of flanges 7 may be fixed to the first flange 7a by a fastener 8 to lock / fix the pair of flanges 7 relative to the shaft 5. The fastener 8 may be a bolt, a screw, or any known fastener.

[0058] Fig.10 Shown in Fig. 9 The step performed after the step of includes attaching a predetermined number of weights 11 to the spring plate 9, the shaft 5 and the end plate 13 by fasteners 15. Fig.10 The end plates 13 are omitted in the figure to better illustrate the connection between adjacent counterweights 11 and the connection between the counterweights 11 and the spring plate 9. As described above, each end face may include a flat surface to flush against the corresponding end face of the adjacent counterweight 11. In addition, each counterweight 11 may be provided with a flange 11a at its end face to connect the counterweight 11 to the corresponding spring plate 9 and the flange 11a of the adjacent counterweight 11 to form a fixed pair of counterweights. The end of each counterweight 11 may also be attached to the corresponding spring plate 9 through the hole 10 of the spring plate 9. For example, the spring plate 9 may be provided with a narrow slot 10 for accommodating a fastener 15 extending from the flange 11a of one counterweight 11 through the corresponding spring plate 9 and reaching the other counterweight 11 to fix two adjacent counterweights 11 and the spring plate 9 to each other. Figure 3 Four spring plates 9 and eight (8) pairs of adjacent counterweights 11 are shown, however, there may be any number of counterweights 11 and spring plates 9.

[0059] Fig.10One method of attaching the counterweight 11 to the shaft 5 is shown, however, any other known method of attaching the counterweight 11 to the shaft 5 may be employed, such as using a clamp, spring collar, bolts or other fastening members. In addition, the counterweight 11 may be attached to the shaft 5 by bonding (i.e., glue, resin, etc. connection), welding, brazing, using a shaft coupling with a set screw, or by any known means. The hole 10 of each counterweight 11 may be threaded to mate with a corresponding threaded portion of the shaft 5, the threaded portion of the shaft 5 being spaced apart from the bearing 16, so as to position the counterweight along the longitudinal axis of the shaft 5. Once positioned, the counterweight 11 may be attached to the shaft 11 using a clamp, spring collar, shaft coupling with a set screw, or other coupling member.

[0060] Fig.11A and 11B Another mass damper system 50 of the present invention is shown, wherein a mass damper of the torsional or viscous type as known in the prior art is attached to Figure 2-10 11 shows a different type of mass damper system 50 attached to a bracket 20 via the shaft 5, and the shaft 5 is connected to the bearing 16 in the above-described manner. In addition, the bracket 20 is attached to the hub 46 via the fastening member 20a, the gear 19 is attached to the pedestrian conveyor sprocket 45, and the shaft 47 is arranged between the hubs 46 in the above-described manner.

[0061] The torsional mass damper may include a plurality of spaced-apart counterweights within an outer housing, which may be a cylindrical housing and a spring between each of two adjacent counterweights, and a friction member engaged with the counterweights to provide torsional damping. During operation of the pedestrian conveyor, vibrations rotate the shaft 5, which causes the cylindrical housing to rotate therein and thus engages the friction member with the outer housing or another component of the torsional mass damper, thereby providing torsional damping.

[0062] An alternative type of torsional mass damper such as a viscous type mass damper may have an outer housing, which may be a cylindrical housing, an inertia ring disposed within the outer housing, and a viscous fluid disposed between the outer housing and the inertia ring. The outer housing may be directly connected to the shaft 5 and may move as the shaft rotates. Internally, the inner inertia ring rotates freely in a layer of viscous fluid. Due to pulses generated during operation of the pedestrian conveyor, the outer housing and the inner inertia ring rotate independently at different speeds. The shearing action generated by the viscous fluid reduces vibrations by converting them into heat.

[0063] Fig. 11B is an enlarged portion of the mass-damper system 50 to emphasize the connection of the end plate 54 to the mass-damper system 50 via the fasteners 56 and the connection of the end plate 54 to the shaft 5 .

[0064] The mass damper system may be provided with a cylindrical housing.

[0065] The shaft 5 of the mass damper system 50 is provided with a stopper 5b to prevent the damper 50 (including its cylindrical housing) from moving axially along the shaft 5, and comprises two end plates 54, each of which is attached to the mass damper system 50 by bolts 56. The stopper 5b may extend transversely to the longitudinal / axial direction of the shaft 5.

[0066] In an alternative embodiment, the shaft 5 may be provided with a stopper 5b to prevent the damper 50 from moving axially along the shaft 5, and a keyway 5a to prevent the damper from rotating about the shaft 5. In other words, each end plate 54 may be provided with a stopper 5b and a keyway 5a to lock the damper 50 to the shaft 5.

[0067] As described above with respect to the mass damper system 1, the mass damper system 50 of the alternative embodiment may be installed at various locations along the pedestrian conveyor to mitigate or eliminate pulses caused by the operation of the pedestrian conveyor.

[0068] Furthermore, as described above, multiple mass damper systems 50 may be disposed on the exterior of the conveyor frame 30 at multiple locations throughout the pedestrian conveyor system. The multiple locations may be determined in the same manner as described above.

[0069] As also described above, the sprocket 17 can be fixed in place and connected to the shaft 5 by a fastening member 18 that engages with the keyway 5a of the shaft 5. In addition, one or more brackets 20 are provided. Each bracket 20 may include a bearing 16. The bracket 20 can be attached to the hub 46. The shaft 5 engages each bearing 16, and the bearing 16 rotates relative to the shaft 5 and fixes the shaft 5 in place. The bracket 20 can be set at any position on the pedestrian conveyor and can be fixed by any known conventional means, such as screws, bolts, brazing, welding, etc. The invention is thus described, and it is obvious that the invention can be changed in many ways. Such changes should not be considered to depart from the spirit and scope of the present invention, and all such modifications that are obvious to those skilled in the art are intended to be included within the scope of the appended claims.

Claims

1. A pedestrian conveyor, comprising: At least one torsional vibration damper system comprising: axis; a cylindrical housing attached to the shaft and configured to damp vibrations of the shaft; a first gear attached to an end of the shaft; and a second gear engaged with the first gear; and a step chain belt connected to the second gear; The first gear and the second gear are sized to reduce the need for large masses, thereby reducing the size of the torsional vibration damper system.

2. The pedestrian conveyor according to claim 1, wherein: The cylindrical housing is a viscous damper comprising a viscous fluid.

3. The pedestrian conveyor according to claim 1, wherein: The cylindrical housing includes a plurality of spaced-apart weights and a spring located between each of two adjacent weights.

4. The pedestrian conveyor according to claim 1, wherein: The shaft includes a plurality of stops extending transversely from an axial direction of the shaft.

5. The pedestrian conveyor according to claim 4, wherein: Each torsional vibration damper system also includes a first end plate and a second end plate, wherein the first end plate is attached to a first end of the cylindrical shell, the second end plate is attached to a second end of the cylindrical shell opposite to the first end, and Wherein, the stopper is configured to limit the movement of the cylindrical housing along the axial direction.

6. The pedestrian conveyor according to claim 1, wherein: The shaft is provided with a keyway, and wherein the cylindrical housing is attached to the shaft via the keyway.

7. A pedestrian conveyor, comprising: A mass damper system comprising: axis; a plurality of spring plates attached to the shaft; a plurality of counterweights connected to the plurality of spring plates; a first gear connected to the shaft; and a second gear engaged with the first gear; and a step chain belt connected to the second gear; The dimensions of the first gear and the second gear are designed to reduce the need for large masses, thereby reducing the size of the mass damper system.

8. The pedestrian conveyor according to claim 7, wherein: The plurality of counterweights abut one another and are attached to one another by fasteners extending through the plurality of counterweights.

9. The pedestrian conveyor according to claim 8, wherein: The mass damper system also includes at least two end plates, each end plate being attached at a respective end of the plurality of counterweights via the fasteners.

10. The pedestrian conveyor according to claim 9, wherein: The end plate is configured to rotate about the shaft and is not fixed to the shaft.

11. The pedestrian conveyor according to claim 7, wherein: Each of the spring plates is attached to the shaft by a fastening member engaging a keyway of the shaft.

12. A method of retrofitting a mass damper system to an existing pedestrian conveyor, the method comprising the steps of: At least one mass damper system is provided, each mass damper system comprising: axis; at least one spring plate or at least one cylindrical housing; and Sprocket; a first gear connected to the shaft; a second gear engaged with the first gear; attaching at least one spring plate or at least one cylindrical housing to the shaft; and attaching the shaft to the pedestrian conveyor via one or more brackets, wherein each bracket includes a bearing engaged with the shaft; The dimensions of the first gear and the second gear are designed to reduce the need for large masses, thereby reducing the size of the mass damper system.

13. The method according to claim 12, wherein: The bracket is also attached to a step sprocket, wherein the step sprocket directly engages the step chain belt of the pedestrian conveyor.

14. The method according to claim 13, wherein: The at least one spring plate comprises a plurality of spring plates, and Each mass damper system further comprises: Multiple end plates; Multiple weights, and The method further comprises: attaching a plurality of end plates to the shaft; After the step of attaching the plurality of end plates to the shaft, providing a plurality of fasteners through each end plate and connecting each fastener to each end plate; and Attach the spring plate to the shaft.

15. The method of claim 14, further comprising attaching each weight to a corresponding spring plate and an adjacent weight in the plurality of weights.

16. The method according to claim 15, wherein: Each counterweight is attached at its end face to a corresponding spring plate, and Each counterweight includes two end surfaces.

17. The method according to claim 16, wherein: The end face of each counterweight abuts the corresponding end face of an adjacent counterweight to form a pair of counterweights, and Therein, each pair of counterweights and corresponding spring plates are attached to each other by fasteners.

18. The method according to claim 12, further comprising: Conducting a vibration analysis of the pedestrian conveyor during operation of the pedestrian conveyor to determine the vibration level of the steps of the pedestrian conveyor; and Wherein the step of performing a vibration analysis is performed before the step of attaching the shaft to the pedestrian conveyor.

19. The method according to claim 18, further comprising: After performing the vibration analysis, determining whether the vibration level exceeds a predetermined threshold; as well as At least one mass damper system is installed at respective locations where vibration levels exceed a predetermined threshold.

20. The method according to claim 12, wherein: The shaft is provided with a keyway, and Therein, the method further comprises attaching at least one spring plate or at least one cylindrical housing to the shaft via a fastening member engaging a keyway of the shaft.

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