Patent Publication Number: US-11655125-B2

Title: Passenger conveyor and guide shoe for passenger conveyor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is based on PCT filing PCT/JP2019/027568, filed Jul. 11, 2019, which claims priority to JP 2019-076334, filed Apr. 12, 2019, the entire contents of each are incorporated herein by reference. 
     TECHNICAL FIELD 
     This invention relates to a passenger conveyor such as an escalator or a moving walk, and to a guide shoe for a passenger conveyor. 
     BACKGROUND ART 
     A related-art passenger conveyor includes balustrades and floor plates. The balustrades are installed in a building structure. The floor plates are installed at both ends of the balustrades in a longitudinal direction thereof. A plurality of steps that are connected endlessly are installed in such a manner as to circulate between the floor plates. Skirt guards are mounted to the balustrades along a moving direction of the steps in such a manner as to be located on both sides of the steps in a width direction thereof. Guide shoes are mounted at both sides of each of the steps in the width direction of the steps. With this configuration, when the steps are moved, the guide shoes are brought into contact with the skirt guards to restrict movement of the steps in the width direction (see, for example, Patent Literature 1). 
     In the passenger conveyor described above, when the guide shoes are moved while being in contact with the skirt guards, specifically, being slid across the skirt guards, the guide shoes cause friction vibration. As a result, a sliding noise is generated from the guide shoes or the vicinity thereof. 
     In the related-art passenger conveyor described in Patent Literature 1, the guide shoes are made of a low-friction material. Thus, generation of the sliding noise is suppressed. Further, in Non Patent Literature 1, the generation of vibration is described in mathematical terms. 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] JP 2011-190043 
       
    
     Non Patent Literature 
     
         
         [NPL 1] “Elucidation of Mechanism of Generation of Self-Excited Vibration by New Complex Mode Analysis and Its Preventive Measures” by Takahiro Kondo, pp. 10 to 12, 18th Autumn Technology Exchange Forum of The Japan Society of Mechanical Engineers, Kansai Branch (Oct. 21, 2017). 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the related-art passenger conveyor, the guide shoes are made of a low-friction material. Thus, the generation of the sliding noise can be suppressed by an effect of the low-friction material for a predetermined time period after mounting of new guide shoes. However, a friction coefficient of a sliding surface of each of the guide shoes increases over time. Thus, the generation of the sliding noise cannot be continuously suppressed through operations of the passenger conveyor for a long period of time. 
     This invention has been made to solve the problems described above, and has an object to provide a passenger conveyor and a guide shoe for a passenger conveyor, which enable suppression of generation of a sliding noise for a long period of time even when a friction coefficient of a sliding surface of the guide shoe has increased over time. 
     Solution to Problem 
     According to one embodiment of the present invention, there is provided a guide shoe for a passenger conveyor, including: a base portion to be slid across a skirt guard provided along a moving direction of a plurality of steps that are movably provided; and a weight containing a material having a specific gravity larger than a specific gravity of a material of the base portion, which is provided to the base portion. 
     Advantageous Effects of Invention 
     According to one embodiment of the present invention, the weight containing a material having a specific gravity larger than a specific gravity of a material of the base portion is provided to the base portion of the guide shoe for a passenger conveyor to increase a mass at a mass point. Thus, even when a friction coefficient of the base portion has increased over time, friction vibration of the guide shoe can be suppressed. Thus, suppression of a sliding noise through operations of the passenger conveyor for a long period of time is achieved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view for illustrating a main part of a passenger conveyor according to a first embodiment of this invention. 
         FIG.  2    is a perspective view of a step of the passenger conveyor according to the first embodiment of this invention. 
         FIG.  3    is an enlarged perspective view for illustrating a main part of the step of the passenger conveyor according to the first embodiment of this invention. 
         FIG.  4    is a perspective view of a guide shoe according to the first embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  5    is a perspective view of a related-art guide shoe to be mounted to a step of a passenger conveyor. 
         FIG.  6    is an analysis model diagram for illustrating a friction vibration phenomenon of the guide shoe for a passenger conveyor in a simplified manner. 
         FIG.  7    is a top view of a guide shoe according to a second embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  8    is a side view of the guide shoe according to the second embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  9    is a top view of a guide shoe according to a third embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  10    is a side view of the guide shoe according to the third embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  11    is a top view of a guide shoe according to a fourth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  12    is a sectional view taken along the line XII-XII in  FIG.  11    when viewed in a direction of arrows. 
         FIG.  13    is a top view of a guide shoe according to a fifth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  14    is a sectional view taken along the line XIV-XIV in  FIG.  13    when viewed in a direction of arrows. 
         FIG.  15    is a top view of a guide shoe according to a sixth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  16    is a sectional view taken along the line XVI-XVI in  FIG.  15    when viewed in a direction of arrows. 
         FIG.  17    is a top view of a guide shoe according to a seventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  18    is a sectional view taken along the line XVIII-XVIII in  FIG.  17    when viewed in a direction of arrows. 
         FIG.  19    is a top view of a guide shoe according to an eighth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  20    is a side view of the guide shoe according to the eighth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  21    is a top view of a guide shoe according to a ninth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  22    is a side view of the guide shoe according to the ninth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  23    is a top view of a guide shoe according to a tenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  24    is a side view of the guide shoe according to the tenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  25    is a top view of a guide shoe according to an eleventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  26    is a side view of the guide shoe according to the eleventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  27    is a top view of a guide shoe according to a twelfth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  28    is a sectional view taken along the line XXVIII-XXVIII in  FIG.  27    when viewed in a direction of arrows. 
         FIG.  29    is a top view of a guide shoe according to a thirteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  30    is a side view of the guide shoe according to the thirteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  31    is a top view of a guide shoe according to a fourteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  32    is a side view of the guide shoe according to the fourteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  33    is a top view of a guide shoe according to a fifteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  34    is a side view of the guide shoe according to the fifteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  35    is a side view of a guide shoe according to a sixteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  36    is a sectional view taken along the line XXXVI-XXXVI in  FIG.  35    when viewed in a direction of arrows. 
         FIG.  37    is a side view of a guide shoe according to a seventeenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  38    is a sectional view taken along the line XXXVIII-XXXVIII in  FIG.  37    when viewed in a direction of arrows. 
         FIG.  39    is a side view of a guide shoe according to an eighteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
         FIG.  40    is a sectional view taken along the line XXXX-XXXX in  FIG.  39    when viewed in a direction of arrows. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       FIG.  1    is a perspective view for illustrating a main part of a passenger conveyor according to a first embodiment of this invention. 
     In  FIG.  1   , the passenger conveyor includes floor plates  1 , a plurality of steps  10 , balustrades  2 , handrails  3 , and skirt guards  4 . The floor plate  1  is installed on each floor of a building. The plurality of steps  10  are connected endlessly and provided in a circulatable manner between the floor plate  1  on an upper floor and the floor plate  1  on a lower floor. The balustrades  2  are installed on both sides of the steps  10  in a width direction of the steps  10  along a moving direction of the steps  10 . The balustrades  2  are installed in such a manner as to be separate from each other in the width direction of the steps  10  and parallel to each other. The handrail  3  is provided along an outer periphery of each of the balustrades  2 , and is configured to be moved in synchronization with movement of the steps  10 . The skirt guard  4  is provided below each of the balustrades  2 . 
     Next, a configuration of each of the steps  10  is described with reference to  FIG.  2    to  FIG.  4   .  FIG.  2    is a perspective view of one of the steps of the passenger conveyor according to the first embodiment of this invention.  FIG.  3    is an enlarged perspective view for illustrating a main part of a step of the passenger conveyor according to the first embodiment of this invention.  FIG.  4    is a perspective view of a guide shoe according to the first embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     The step  10  includes, as illustrated in  FIG.  2   , a step tread  11 , a riser  12 , and triangular brackets  13 . The step tread  11  is configured to allow a passenger to stand thereon. The riser  12  is a stair riser. The triangular brackets  13  are arranged on a side opposite to a tread surface of the step tread  11  in such a manner as to be separate from each other in a width direction of the step tread  11 . The triangular brackets  13  are frames configured to support both ends of the step tread and the riser  12  in the width direction. A fitting portion  14  having a C-like shape is provided to an end portion of each of the triangular brackets  13 , which is on a side opposite to the riser  12 . A connector (pipe sleeve)  15  configured to enable mounting of a guide shoe  20 A is provided to each of the triangular brackets  13 . The connector  15  is provided on a side of the fitting portion  14 , which is opposite to the riser  12 , in such a manner as to be adjacent to the fitting portion  14 . A rear wheel  16  is provided at an end portion of each of the triangular brackets  13 , which is on the riser  12  side. Although not shown, a step front-wheel shaft is fitted into the fitting portions  14  of the triangular brackets  13 . Then, front wheels are mounted to both ends of the step front-wheel shaft. The front wheels, which are mounted to the step front-wheel shafts, are connected through intermediation of endless step chains. 
     Although not shown, the front wheels of the steps  10  having the configuration described above are connected to the endless step chains, and the steps  10  are installed endlessly between the floor plate  1  on the upper floor and the floor plate on the lower floor. Then, the step chains are driven to circulate the steps  10  between the floor plate  1  on the upper floor and the floor plate  1  on the lower floor. 
     In this case, as illustrated in  FIG.  3   , the connector  15  is formed in a cylindrical shape, and is provided to each of the triangular brackets  13  in such a manner that an axial direction of the connector  15  matches the width direction of the step tread  11 . Further, in some passenger conveyors, the connector  15  may have a rectangular parallelepiped shape as a member configured to enable the mounting of the guide shoe  20 A. Specifically, the connector  15  is a structure configured to enable the mounting of the guide shoe  20 A or to hold a base portion  21  of the guide shoe  20 A, which is described later, in the passenger conveyor. The connector  15  is formed in such a manner that a protruding amount of the connector  15  beyond the step  10  lies within a specified range. The axial direction of the connector  15  is perpendicular to a sliding surface of the skirt guard  4  across which the base portion  21  of the guide shoe  20 A is to be slid, which is described later. A contact surface of the connector  15 , which is an axially outer end surface of the connector  15 , is a flat surface orthogonal to the axial direction of the connector  15 . A pair of guide grooves  15   a  are formed in an inner wall of a peripheral wall portion of the connector  15 . The pair of guide grooves  15   a  are formed so as to be opposed to each other across an axis of the connector  15  and to extend in parallel to the axis. A pair of insertion holes  15   b  are formed in the peripheral wall portion of the connector  15 . The pair of insertion holes  15   b  are formed so as to be opposed to each other across the axis of the connector  15  in such a manner as to bring the pair of guide grooves  15   a  and an outside of the connector  15  into communication with each other. A pair of fitting grooves  15   c  are formed in the contact surface of the connector  15  so as to be opposed to each other across the axis of the connector  15 . A direction in which the pair of guide grooves  15   a  are opposed to each other is orthogonal to a direction in which the pair of fitting grooves  15   c  are opposed to each other. 
     The guide shoe  20 A includes, as illustrated in  FIG.  4   , the base portion  21 , weights  22 , a pair of leg portions  23 , claw portions  24 , and a protruding portion  25 . The base portion  21  is to be slid across the sliding surface of the skirt guard  4  when the steps  10  are moved. The weights  22  are configured to add a mass to the base portion  21 . The pair of leg portions  23  are configured to enable mounting of the base portion  21  to the connector  15 . The claw portions  24  are provided at distal ends of the leg portions  23 , respectively. The protruding portion  25  is configured to position the base portion  21 . 
     The base portion  21  is a low friction material, and is formed in a flat rectangular parallelepiped shape using a material having appropriate elasticity, such as a polyacetal resin, a polytetrafluoroethylene resin, a polyamide resin, a polyethylene resin, a polyphenylene sulfide resin, a polyolefin resin, a phenol resin, or a polyether ether ketone resin. The weights  22  are mounted to a surface of the base portion  21  on a side opposite to a sliding surface of the base portion  21 , which is to be slid across the sliding surface of the skirt guard  4 , that is, a back surface of the base portion  21  by bonding or welding in a state of being in contact with the base portion  21 . The weights  22  are provided in the vicinity of short sides of the rectangular back surface of the base portion  21  in such a manner as to be separate from each other in a longitudinal direction of long sides of the back surface. Each of the weights  22  is formed in a rectangular parallelepiped shape with use of a material having a specific gravity larger than that of a material of the base portion  21 , for example, a metal such as iron, aluminum, copper, lead, or tungsten, a stone material, and glass. The pair of leg portions  23  are formed so as to extend from the back surface of the base portion  21  in a direction perpendicular to the sliding surface of the base portion  21 . The claw portions  24  are provided in such a manner as to protrude outward from protruding ends of the pair of leg portions  23  in a direction in which the leg portions  23  are opposed to each other. The protruding portion  25  has such a shape that can be fitted into the fitting grooves  15   c , and is provided at a central position between the pair of leg portions  23  on the back surface of the base portion  21 . The protruding portion  25  extends in a direction orthogonal to the direction in which the pair of leg portions  23  are opposed to each other. 
     To mount the guide shoe  20 A having the configuration described above to the step  10 , the pair of leg portions  23  are first elastically deformed in such a manner as to reduce a distance between the claw portions  24 , and the claw portions  24  are inserted into the pair of guide grooves  15   a . Subsequently, the pair of leg portions  23  are inserted into the connector  15 . In this manner, the claw portions  24  are moved in the pair of guide grooves  15   a . When the claw portions  24  reach positions of the insertion holes  15   b , the leg portions  23  return to their original states to thereby fit the pair of claw portions  24  into the insertion holes  15   b . At this time, the protruding portion  25  is inserted into the fitting grooves  15   c . As a result, the guide shoe  20 A is mounted to the step  10  with the base portion  21  being located on an outer side in the width direction of the step tread  11 . The claw portions  24  inserted into the insertion holes  15   b  prevent disengagement of the guide shoe  20 A from the connector  15 . Further, the protruding portion  25  fitted into the fitting grooves  15   c  prevents rotation of the guide shoe  20 A about the axis of the connector  15  and positions the guide shoe  20 A. Further, the weights  22  are in contact with the base portion  21 , and are separate from components of the step  10 , such as the step tread  11 , the riser  12 , the triangular bracket  13 , and the connector  15 , and the skirt guard  4 . 
       FIG.  5    is a perspective view of a related-art guide shoe to be mounted to a step of a passenger conveyor. As illustrated in  FIG.  5   , the related-art guide shoe  100  has the same configuration as that of the guide shoe  20 A of the present application except that the weights  22  are not provided. 
     Now, a description is given of a schema of a phenomenon of generation of an abnormal noise, which is caused along with sliding movement of the guide shoe, and dynamic effects of a guide shoe structure. 
     First, as a general sliding phenomenon, when one of two members is slid across the other one and a friction coefficient of a sliding surface becomes equal to or larger than a given value, a vibration amplitude of the member tends to significantly increase. However, this phenomenon is not determined based only on a magnitude of a value of the friction coefficient, but is also affected by other parameters. For example, vibration is suppressed by increasing a mass at a mass point portion in a friction vibration system. 
     In the present invention, the above-mentioned characteristics in the sliding phenomenon are applied to a structure of the guide shoe for a passenger conveyor. 
     The guide shoe  20 A is subjected to a frictional force from the skirt guard  4  with the leg portions  23  mounted to the step  10  being fixed ends. A mass point portion in this friction vibration system corresponds to the base portion  21 , which is located at a distal end of the guide shoe  20 A. The related-art guide shoe  100  illustrated in  FIG.  5    does not include the weights  22 . Thus, a mass of the base portion  21  is small. Further, a friction coefficient of the sliding surface of the base portion  21 , which is to be slid across the skirt guard  4 , increases over time. Thus, when the related-art guide shoe  100  is used, generation of a sliding noise cannot be continuously suppressed through operations of the passenger conveyor for a long period of time. 
     Thus, for the suppression of vibration, it is effective to increase the mass of the base portion  21 . When the weights  22  containing a material having a specific gravity larger than that of a material of the base portion are provided to the base portion  21 , the vibration of the base portion  21  can be suppressed. However, when the weights  22  provided to the base portion  21  are brought into contact with a component of the step  10 , such as the connector  15  of the step  10 , which serves as a ground in the friction vibration system, and are supported by the component of the step  10 , a desired increase in mass cannot be achieved at the mass point portion in some cases. An experiment was actually conducted under a state in which the weights were in contact with a component of the step. As a result, a reduction in vibration was not achieved in some cases. In the first embodiment, the weights  22  may be mounted to the base portion  21  in a state of being in contact only with the base portion  21  so as not to be brought into contact with the components of the step  10 , such as the connector  15  of the step  10  and other components provided therearound. Specifically, the weights  22  are arranged in such a manner that a clearance is defined between the weights  22  and the components of the steps  10 . In other words, the weights  22  are arranged so as not to be in contact with or so as to be separate from the components of the step  10 , which include the connector  15  and the components provided therearound. Further, the guide shoe  20 A may be mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In the manner described above, the weights  22  add a mass to the base portion  21 . Further, the weights  22  are made of a material having a specific gravity larger than that of a material of the base portion  21 . According to the first embodiment, the mass of the base portion  21  can be efficiently increased while an increase in volume of the guide shoe  20 A is reduced. As a result, even when the friction coefficient of the sliding surface of the base portion  21  has increased over time, the friction vibration of the guide shoe  20 A can be suppressed. Thus, the suppression of the sliding noise through the operations of the passenger conveyor for a long period of time can be achieved. 
     Further, there exist a plurality of kinds of phenomena in which the vibration amplitude is increased due to an influence of the frictional force. The inventors have conducted an experiment and an investigation on the friction vibration of the guide shoe. As a result, it was found that, in a case of the guide shoe, a vibration destabilization phenomenon occurs due to asymmetry of a mass matrix, a stiffness matrix, and a damping matrix of the guide shoe. 
       FIG.  6    is an analysis model diagram for illustrating a friction vibration phenomenon of the guide shoe in a simplified manner. The guide shoe  100  is suspended from a horizontal upper support portion corresponding to the connector  15  through two hanger springs. The two hanger springs are connected to the upper support portion, and are provided at positions separate from each other in a horizontal direction. The guide shoe  100  is a rigid body having a mass M. A lower support portion corresponding to the skirt guard  4  is located below the guide shoe  100 . A contact spring having a spring constant “k c ” is provided to the lower support portion so as to be in contact with the guide shoe  100 . The guide shoe  100  is pressed against the lower support portion through the contact spring. The lower support portion is moved at a constant velocity with respect to the guide shoe  100  in the horizontal direction. A kinetic frictional force as a coulomb frictional force acts on the guide shoe  100  at a contact point of the contact spring with the guide shoe  100 . Only a translational motion in a vertical direction and a rotational motion about a center of gravity are possible as motions of the guide shoe  100 . The rotational motion of the guide shoe  100  about the center of gravity is a rotational motion in a plane that is orthogonal to the lower support portion and extends along a moving direction of the lower support portion. When a moment of inertia about the center of gravity of the guide shoe  100  is represented by J, a vertically downward displacement of the guide shoe  100  from a non-vibrational equilibrium state as a reference is represented by “x”, and an angular displacement about the center of gravity is represented by θ, an equation of motion of this system is expressed by Expression (1). 
     
       
         
           
             
               
                 
                   
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     In Expression (1), K/2 is a spring constant of each of the hanger springs, “k c ” is the spring constant of the contact spring, L is a dimension between the center of gravity of the guide shoe  100  and one of the hanger springs in the horizontal direction, μ is a dynamic friction system coefficient of the contact spring for the guide shoe  100 , a sign of “a” is defined to be positive when “a” is on the left side of the center of gravity of the guide shoe  100  in  FIG.  6   , and “b” is a dimension between the contact point of the contact spring with the guide shoe  100  and the center of gravity of the guide shoe  100  in the vertical direction. A plurality of non-dimensional parameters are now introduced. Then, the equation of motion of this system is expressed by Expression (2). 
     
       
         
           
             
               
                 
                   
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     A mass matrix and a stiffness matrix have asymmetry. In this case, the following is mathematically derived as described in Non Patent Literature 1. Specifically, when a value of α and a value of β do not satisfy conditions of Expression (3), a vibration amplitude of the guide shoe  100  increases. 
     
       
         
           
             
               
                 
                   
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     In the related-art guide shoe  100  illustrated in  FIG.  5   , the values of α and β do not satisfy the stabilization conditions described above. Hence, a significant increase in vibration amplitude occurs. Thus, as one of means for stabilizing the vibration, there is given means for setting a large value to α so as to satisfy Expression (4) for the structure of the related-art guide shoe  100 . 
     
       
         
           
             
               
                 
                   
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     Similarly, there is given means for setting a small value to β within a range smaller than 0 to satisfy Expression (5) for the structure of the related-art guide shoe  100 . 
     
       
         
           
             
                 
             
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     To increase the value of α for the related-art guide shoe  100 , it is required that a value of a rotation radius J/M of the guide shoe  100  be increased. Specifically, the moment of inertia J about the center of gravity of the guide shoe  100  is required to be increased in a plane that is orthogonal to the sliding surface of the skirt guard and the sliding surface of the base portion  21  of the guide shoe  100  and extends along a sliding direction in which the base portion  21  is slid across the skirt guide. The center of gravity in this case corresponds to a center of gravity of the base portion  21 . 
     Further, to reduce the value of β for the related-art guide shoe  100 , it is required that the distance “b” from a contact point between the skirt guard and the base portion  21  to the center of gravity of the base portion  21  be increased. In the above-mentioned manner, a sliding state of the guide shoe  100  across the skirt guard  4  is stabilized to thereby suppress the generation of the sliding noise through the operations of the passenger conveyor for a long period of time. 
     In this embodiment, in the guide shoe  20 A, the weights  22  are provided at such positions that a moment of inertia about a combined center of gravity of the base portion  21  and the weights  22  is larger than a moment of inertia about the center of gravity of the base portion  21  in the plane that is orthogonal to the sliding surface of the skirt guard  4  and the sliding surface of the base portion  21  and extends along the sliding direction in which the base portion  21  is slid across the skirt guard  4 . Specifically, the guide shoe  20 A includes the base portion  21  and the weights  22 . The base portion  21  is to be slid across the skirt guard  4  provided along the moving direction of the plurality of steps  10  that are movably provided. The weights  22  are provided to the base portion  21 , and are configured to increase a rotation radius of a pitching motion in the moving direction of the base portion  21 . Thus, the sliding state of the guide shoe  20 A across the skirt guard  4  can be stabilized, and thus the generation of the sliding noise of the guide shoe  20 A, which may be caused by sliding across the skirt guard  4 , can be further suppressed. The pitching motion is a rotational motion of the base portion  21 , which occurs about the center of gravity in the plane that is orthogonal to the sliding surface of the skirt guard  4  and the sliding surface of the base portion  21  and extends along the sliding direction of the base portion  21  across the skirt guard  4 . 
     A combined center of gravity corresponds to a center of gravity when the weights are mounted to the base portion and the base portion and the weights are regarded as one integral body. 
     In the first embodiment described above, the weights  22  may be mounted to the base portion  21  in a state of being in contact only with the base portion  21 . The guide shoe  20 A may be mounted to the connector  15  in such a manner that a clearance is defined between the weights  22  and the components of the step  10 . However, the weights  22  may be in contact not only with the base portion  21  but also with the components of the guide shoe  20 A other than the base portion  21 , for example, the leg portions  23  as long as a clearance is defined between the weights  22  and the components of the step  10 . Also in other embodiments, the weights may be in contact not only with the base portion but also with the components of the guide shoe other than the base portion, for example, the leg portions as long as a clearance is defined between the weights and the components of the step. 
     In the first embodiment described above, the weights  22  containing a material having a specific gravity larger than that of a material of the base portion are provided to the base portion  21  to be located at such positions that a moment of inertia about a combined center of gravity of the base portion  21  and the weights  22  is larger than the moment of inertia about the center of gravity of the base portion  21 . As a result, the vibration of the base portion  21  can be further reliably suppressed. 
     In each of first to eighteenth embodiments, description is given of a configuration in which a mass of the guide shoe is increased. Further, in each of the first to thirteenth embodiments, description is given of a configuration in which the value of α is increased, specifically, the moment of inertia about the combined center of gravity of the base portion and the weights in a case in which the weights are provided to the base portion is larger than the moment of inertia about the center of gravity of the base portion in the plane that is orthogonal to the sliding surface of the skirt guard and the sliding surface of the base portion and extends along the sliding direction of the base portion across the skirt guard. In each of the fourteenth to eighteenth embodiments, description is given of a configuration in which the value of β is reduced, specifically, the distance “b” from the contact point between the skirt guard and the base portion to the combined center of gravity of the base portion and the weights in a case in which the weights are provided to the base portion is larger than the distance “b” from the contact point between the skirt guard and the base portion to the center of gravity of the base portion. 
     Second Embodiment 
       FIG.  7    is a top view of a guide shoe according to a second embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  8    is a side view of the guide shoe according to the second embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  7    and  FIG.  8   , one weight  22  is fixed to the back surface of the base portion  21  by, for example, bonding or welding in a state of being in contact with the base portion  21 . 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 B according to the second embodiment, the weight  22  made of a material having a specific gravity larger than that of a material of the base portion  21  is provided to the back surface of the base portion  21  in a state of being in contact with the base portion  21 . Further, the weight  22  is provided at such a position that, when the weight  22  is provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weight  22  is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 B may also be mounted to the connector  15  in such a manner that the weight  22  is separate from the skirt guard  4 . In this case, the weight  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the second embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     Third Embodiment 
       FIG.  9    is a top view of a guide shoe according to a third embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  10    is a side view of the guide shoe according to the third embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  9    and  FIG.  10   , the weights  22  are fixed to four corners of the rectangular back surface of the base portion  21  by, for example, bonding or welding, in a state of being in contact with the base portion  21 . 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 C according to the third embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the back surface of the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weights is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 C is mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the third embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     In the first to third embodiments, the numbers of weights  22  to be provided on the back surface of the base portion  21  are one, two, and four. However, the number of weights  22  to be provided on the back surface of the base portion  21  is only required to be equal to or larger than one, and the number thereof is not limited. 
     Fourth Embodiment 
       FIG.  11    is a top view of a guide shoe according to a fourth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  12    is a sectional view taken along the line XII-XII in  FIG.  11    when viewed in a direction of arrows. 
     In  FIG.  11    and  FIG.  12   , the weights  22  are fixed to the back surface of the base portion  21  with screws  26  in a state of being in contact with the base portion  21 . 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 D according to the fourth embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the back surface of the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weights is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 D is mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the fourth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     Fifth Embodiment 
       FIG.  13    is a top view of a guide shoe according to a fifth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  14    is a sectional view taken along the line XIV-XIV in  FIG.  13    when viewed in a direction of arrows. 
     In  FIG.  13    and  FIG.  14   , similarly to the base portion  21 , a base portion  21 A is made of a low-friction material, and is formed in a flat rectangular parallelepiped shape. Fitting recessed portions  27  are formed in the back surface of the base portion  21 A. Similarly to the weight  22 , each of weights  22 A is made of a material having a specific gravity larger than that of a material of the base portion  21 A, and is formed in a rectangular parallelepiped shape. Fitting protruding portions  28  are formed on a bottom surface of each of the weights  22 A. After the fitting protruding portions  28  are fitted into the fitting recessed portions  27 , bonding therebetween is performed as needed. In this manner, the weights  22 A are fixed to the base portion  21 A. 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 E according to the fifth embodiment, the weights  22 A made of a material having a specific gravity larger than that of a material of the base portion  21 A are provided to the back surface of the base portion  21 A so as to be in contact with the base portion  21 A. Further, the weights  22 A are provided at such positions that, when the weights  22 A are provided to the base portion  21 A, a moment of inertia about a combined center of gravity of the base portion  21 A and the weights  22 A is larger than a moment of inertia about the center of gravity of the base portion  21 A. Further, the guide shoe  20 E is mounted to the connector  15  in such a manner that the weights  22 A are separate from the skirt guard  4 . In this case, the weights  22 A may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the fifth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     Sixth Embodiment 
       FIG.  15    is a top view of a guide shoe according to a sixth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  16    is a sectional view taken along the line XVI-XVI in  FIG.  15    when viewed in a direction of arrows. 
     In  FIG.  15    and  FIG.  16   , similarly to the base portion  21 , a base portion  21 B is made of a low-friction material, and is formed in a flat rectangular parallelepiped shape. Fitting recessed portions  29  are formed in the back surface of the base portion  21 B. After the weights  22  are fitted into the fitting recessed portions  29 , bonding therebetween is performed as needed. In this manner, the weights  22  are fixed to the base portion  21 B. 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 F according to the sixth embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21 B are provided to the back surface of the base portion  21 B so as to be in contact with the base portion  21 B. Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 B, a moment of inertia about a combined center of gravity of the base portion  21 B and the weights  22  is larger than a moment of inertia about the center of gravity of the base portion  21 B. Further, the guide shoe  20 F is mounted to the connector  15  in such a manner that the weights are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the sixth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     In the first to sixth embodiments described above, the weight is fixed to the base portion by, for example, integral molding, bonding, welding, screws, or fitting between the recessed portions and the protruding portions. However, fixing means is not limited to the means described above. The weight may be fixed to the base portion with use of a tape, a wire, or a rope. Further, when the weight is made of a magnetic material, the weight may be fixed to the base portion with use of a magnet. 
     Seventh Embodiment 
       FIG.  17    is a top view of a guide shoe according to a seventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  18    is a sectional view taken along the line XVIII-XVIII in  FIG.  17    when viewed in a direction of arrows. 
     In  FIG.  17    and  FIG.  18   , similarly to the base portion  21 , a base portion  21 C is made of a low-friction material, and is formed in a flat rectangular parallelepiped shape. The weights  22  are embedded in the base portion  21 C by insert molding into the base portion  21 C. 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 G according to the seventh embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21 C are provided in the base portion  21 C in an embedded manner. Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 C, a moment of inertia about a combined center of gravity of the base portion  21 C and the weights  22  is larger than a moment of inertia about the center of gravity of the base portion  21 C. Further, the guide shoe  20 G is mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the seventh embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     According to the seventh embodiment, the weights  22  are embedded in the base portion  21 C. With this arrangement, occurrence of defective mounting of the weights  22  at a time of manufacture of the guide shoe  20 G can be prevented. Further, even when an external force acts on the weights  22  at a time of mounting of the guide shoe  20 G and at a time of operation of the passage conveyor, separation and detachment of the weights  22 G from the base portion  21 C can be prevented. 
     Eighth Embodiment 
       FIG.  19    is a top view of a guide shoe according to an eighth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  20    is a side view of the guide shoe according to the eighth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  19    and  FIG.  20   , a weight  22 B is made of a material having a specific gravity larger than that of a material of the base portion  21 , and is formed in a flat ring-like shape. The weight  22 B is fixed to the back surface of the base portion  21  by, for example, bonding or welding in such a manner as to surround the pair of leg portions  23  and the protruding portion  25  without being in contact with the pair of leg portions  23  and the protruding portion  25 . 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 H according to the eighth embodiment, the weight  22 B made of a material having a specific gravity larger than that of a material of the base portion  21  is provided to the back surface of the base portion  21  so as to be in contact with the base portion  21 . Further, the weight  22 B is provided at such a position that, when the weight  22 B is provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weight  22 B is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 H is mounted to the connector  15  in such a manner that the weight  22 B is separate from the skirt guard  4 . In this case, the weight  22 B may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the eighth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     According to the eighth embodiment, the weight  22 B is formed in a flat ring-like shape. With this shape, even when the weight  22 B comes off the base portion  21  during operation of the passenger conveyor, falling of the weight  22 B into the passenger conveyor is prevented. 
     Ninth Embodiment 
       FIG.  21    is a top view of a guide shoe according to a ninth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  22    is a side view of the guide shoe according to the ninth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  21    and  FIG.  22   , each of weights  22 C is formed by laminating and integrating weight pieces  22   a  and  22   b  through, for example, bonding or welding. The weight pieces  22   a  and  22   b  are made of a material having a specific gravity larger than that of a material of the base portion  21 , and are each formed in a flat rectangular parallelepiped shape. A weight of the weights  22 C is the same as that of the weights  22 . The weights  22 C are fixed to the back surface of the base portion  21  by bonding or welding in a state of being in contact with the base portion  21 . 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  201  according to the ninth embodiment, the weights  22 C made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the back surface of the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22 C are provided at such positions that, when the weights  22 C are provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weights  22 C is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  201  is mounted to the connector  15  in such a manner that the weights  22 C are separate from the skirt guard  4 . In this case, the weights  22 C may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the ninth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     In the ninth embodiment, two weight pieces  22   a  and  22   b  are fixed by bonding or welding. A method of fixing the weight pieces  22   a  and  22   b  is not limited to bonding or welding. Further, each of the weights  221  is divided into two weight pieces  22   a  and  22   b . However, the number of division of the weight is not limited to two. 
     Tenth Embodiment 
       FIG.  23    is a top view of a guide shoe according to a tenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  24    is a side view of the guide shoe according to the tenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  23    and  FIG.  24   , the weights  22  are fixed to a pair of side surfaces of the base portion  21 , which are opposed to each other, by, for example, bonding or welding. In this case, the side surfaces are orthogonal to the sliding surface of the base portion  21  formed in a flat rectangular parallelepiped shape. 
     Other configurations are the same as those of the guide shoe in the first embodiment described above. 
     Also in a guide shoe  20 J according to the tenth embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the pair of side surfaces of the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weights  22  is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  201  may also be mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . Specifically, the weights  22  may be in contact with the base portion  21 , and may be separate from components of the step  10 , such as the step tread  11 , the riser  12 , the triangular bracket  13 , and the connector  15 , and the skirt guard  4 . 
     Thus, also in the tenth embodiment, the same effects as those obtained in the first embodiment described above are obtained. 
     Eleventh Embodiment 
       FIG.  25    is a top view of a guide shoe according to an eleventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  26    is a side view of the guide shoe according to the eleventh embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  25    and  FIG.  26   , the weights  22  are fixed to the other pair of side surfaces of the base portion  21 , which are opposed to each other, by, for example, bonding or welding. 
     Other configurations are the same as those of the guide shoe in the tenth embodiment described above. 
     Also in a guide shoe  20 K according to the tenth embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the other pair of side surfaces of the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 , the moment of inertia about a combined center of gravity of the base portion  21  and the weights  22  is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 K is mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the eleventh embodiment, the same effects as those obtained in the tenth embodiment described above are obtained. 
     Twelfth Embodiment 
       FIG.  27    is a top view of a guide shoe according to a twelfth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  28    is a side view of the guide shoe according to the twelfth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  27    and  FIG.  28   , a weight  22 D is made of a material having a specific gravity larger than that of a material of the base portion  21 , and is formed in a rod-like shape. The weight  22 D is provided in the base portion  21  by insert molding into the base portion  21 . 
     Other configurations are the same as those of the guide shoe in the tenth embodiment described above. 
     Also in a guide shoe  20 L according to the twelfth embodiment, the weight  22 D made of a material having a specific gravity larger than that of a material of the base portion  21  is provided to the base portion  21  so as to be in contact with the base portion  21 . Further, the weight  22 D is provided at such a position that, when the weight  22 D is provided to the base portion  21 , a moment of inertia about a combined center of gravity of the base portion  21  and the weight  22 D is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 L is mounted to the connector  15  in such a manner that the weight  22 D is separate from the skirt guard  4 . In this case, the weight  22 D may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the twelfth embodiment, the same effects as those obtained in the tenth embodiment described above are obtained. 
     Thirteenth Embodiment 
       FIG.  29    is a top view of a guide shoe according to a thirteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  30    is a side view of the guide shoe according to the thirteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  29    and  FIG.  30   , the weights  22  are fixed in the vicinity of both end sides of the back surface and to the pair of opposed side surfaces of the base portion  21  on a one-by-one basis by, for example, bonding or welding. 
     Other configurations are the same as those of the guide shoe in the tenth embodiment described above. 
     Also in a guide shoe  20 M according to the thirteenth embodiment, the weights  22  made of a material having a specific gravity larger than that of a material of the base portion  21  are provided to the base portion  21  so as to be in contact with the base portion  21 . Further, the weights  22  are provided at such positions that, when the weights  22  are provided to the base portion  21 , a moment of inertia about a combined center of gravity of the base portion and the weights is larger than the moment of inertia about the center of gravity of the base portion  21 . Further, the guide shoe  20 M is mounted to the connector  15  in such a manner that the weights  22  are separate from the skirt guard  4 . In this case, the weights  22  may be arranged without being in contact with the connector  15  or the components of the step  10 , or may be arranged apart therefrom. 
     Thus, also in the thirteenth embodiment, the same effects as those obtained in the tenth embodiment described above are obtained. 
     In the eighth to eleventh and thirteenth embodiments described above, the weight is fixed to the base portion by, for example, bonding or welding. However, fixing means is not limited to the means described above. The weight may be fixed to the base portion by screws, fitting between recessed portions and protruding portions, a tape, a wire, or a rope. Further, when the weight is made of a magnetic material, the weight may be fixed to the base portion with use of a magnet. 
     The inventors actually conducted an experiment. When the specific gravity of the weight was smaller than the specific gravity of the base portion, a sufficient vibration suppression effect was not obtained. Thus, it is preferred that the specific gravity of the weight be 1.2 or more times the specific gravity of the base portion. In each of the embodiments, it is preferred that a weight of the weight be 0.5 or more times that of the base portion. Further, a likelihood of the suppression of vibration increases as the specific gravity of the weight is increased with respect to the specific gravity of the base portion. In view of installation and maintenance workability, however, it is preferred that an upper-limit specific gravity of the weight be 25 or less times the specific gravity of the base portion. 
     Further, in the first to sixth and eighth to thirteenth embodiments described above, the weights  22  are made of a material having a specific gravity larger than that of a material of the base portion  21 . 
     To suppress the vibration of the guide shoe, it is effective to set the value of β small so as to satisfy Expression (5). In the fourteenth to eighteenth embodiments, when a weight  30  is provided to the related-art guide shoe  100 , the generation of the sliding noise can be suppressed. Specifically, when the weight  30  is provided to the base portion  21 , the value of β can be reduced not only by an increase in mass of each of guide shoes ON to  20 R but also by achievement of a large distance “b” from the contact point between the skirt guard  4  and the base portion  21  to the combined center of gravity of the base portion  21  and the weight  30 . Thus, a sliding state of the guide shoes  20 N to  20 R across the skirt guard  4  can be stabilized. As a result, the generation of the sliding noise by each of the guide shoes  20 N to  20 R can be suppressed through operations of the passenger conveyor for a long period of time. A distance from the contact point between the base portion  21  and the skirt guard  4  to the center of gravity of the base portion  21  is referred to as “gravity-center distance”. 
     Fourteenth Embodiment 
       FIG.  31    is a top view of the guide shoe  20 N according to the fourteenth embodiment of this invention.  FIG.  32    is a side view of the guide shoe  20 N according to the fourteenth embodiment of this invention. As illustrated in  FIG.  31   , the guide shoe  20 N in this embodiment is formed to have the same configurations as those of the guide shoe  20  described in the first to thirteenth embodiments except that weights  30  are provided. 
     A pair of weights  30  are provided on the back surface of the base portion  21  in such a manner as to protrude toward the connector  15 . A position of a combined center of gravity when the base portion  21  and the weights  30  are regarded as an integrated body is farther from the skirt guard than a position of the center of gravity of the base portion  21  alone. Specifically, a larger gravity-center distance than that in the related-art guide shoe  100  is ensured. 
     Fifteenth Embodiment 
       FIG.  33    is a top view of a guide shoe  200  according to a fifteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  34    is a side view of the guide shoe  200  according to the fifteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor. 
     In  FIG.  33    and  FIG.  34   , the pair of weights  30  are provided to a pair of long-side side surfaces of the base portion  21 , respectively. An end portion of each of the weights  30  on the connector  15  side protrudes toward the connector  15  beyond the back surface of the base portion  21 . Other configurations are the same as those of the guide shoe in the fourteenth embodiment described above. 
     Sixteenth Embodiment 
       FIG.  35    is a top view of a guide shoe  20 P according to a sixteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  36    is a sectional view taken along the line XXXVI-XXXVI in  FIG.  35    when viewed in a direction of arrows. 
     In  FIG.  35    and  FIG.  36   , similarly to the base portion  21 , a base portion  21 D is made of a low-friction material. Further, the weights  30  are embedded by insert molding into a front portion and a rear portion of the base portion  21 D in the sliding direction across the skirt guard  4 . As a result of the embodiment of the weights  30  in the base portion  21 D, the back surface of the base portion  21 D has portions protruding toward the connector  15 . 
     Seventeenth Embodiment 
       FIG.  37    is a top view of a guide shoe according to a seventeenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  38    is a sectional view taken along the line XXXVIII-XXXVIII in  FIG.  37    when viewed in a direction of arrows. 
     In  FIG.  37    and  FIG.  38   , the pair of weights  30  are provided on the back surface of the base portion  21 D. Other configurations are the same as those of the guide shoe in the sixteenth embodiment. 
     Eighteenth Embodiment 
       FIG.  39    is a top view of a guide shoe according to an eighteenth embodiment of this invention, which is to be mounted to a step of the passenger conveyor.  FIG.  40    is a sectional view taken along the line XXXX-XXXX in  FIG.  39    when viewed in a direction of arrows. 
     In  FIG.  39    and  FIG.  40   , a weight  30 B has a conical tube-like shape, which is an annular shape without a tapered distal end of a cone. A tapered side of the weight  30 B is placed in contact with the back surface of the base portion  21 . 
     According to the eighteenth embodiment, the weight  30 B has an annular conical tube-like shape. Thus, the gravity-center distance of the guide shoe can be ensured without contact of the weight  30 B with the connector  15 . 
     Further, in the fourteenth to eighteenth embodiments described above, the weight  30  is made of a material having a specific gravity larger than that of a material of the base portion  21 . 
     Further, the weight  30  is formed in such a manner as to be integrated with the base portion  21  by integral molding with the base portion  21 , bonding, or welding. The weight  30  may be made of a material having a specific gravity larger than that of the material of the base portion  21 . As examples of a material having a specific gravity larger than that of the material of the base portion  21 , there are given a metal such as iron, aluminum, copper, lead, or tungsten, a stone material, and glass. 
     In the first to sixth and eighth to thirteenth embodiments described above, the weight  22  is made of a material having a specific gravity larger than that of the material of the base portion  21 . However, when the weight  22  is provided at such a position that the moment of inertia about the combined center of gravity of the base portion  21  and the weight(s)  22  becomes larger, the weight  22  may be made of a material having a specific gravity equal to or smaller than the specific gravity of the material of the base portion  21 . As examples of a material having a specific gravity equal to or smaller than the specific gravity of the material of the base portion  21 , there are given a resin material, a rubber material, and a wood material. With the configuration described above, an increase in weight of the guide shoe can be reduced. Thus, ease of installation and maintenance workability for the passenger conveyor can be improved. In particular, when the same material as the material of the base portion  21  is used as the material of the weight  22 , manufacture cost of the guide shoe can be reduced. 
     Further, in the fourteenth to eighteenth embodiments described above, the weight  30  is made of a material having a specific gravity larger than that of the material of the base portion  21 . However, the weight  30  may be made of a material having a specific gravity equal to or smaller than the specific gravity of the material of the base portion  21 . As examples of a material having a specific gravity equal to or smaller than the specific gravity of the material of the base portion  21 , there are given a resin material, a rubber material, and a wood material. With this configuration, an increase in weight of the guide shoe can be reduced. Thus, ease of installation and maintenance workability for the passenger conveyor can be improved. Further, when the same material as the material of the base portion  21  is used as the material of the weight  30 , manufacture cost of the guide shoe  20 A can be reduced. 
     In each of the embodiments described above, the guide shoes are provided on the front wheel side of the step. However, the guide shoes may be provided to the rear wheel side of the step, or may be provided to each of the front wheel side and the rear wheel side. 
     Further, in each of the embodiments described above, the weight is made of a single material having a specific gravity larger than that of a material of the base portion. However, the weight may be made of a plurality of materials as long as the plurality of materials include a material having a specific gravity larger than that of the material of the base portion. Further, even when a fixing member configured to fix the weight to the base portion functions as a part of the weight configured to add a mass to the base portion, the fixing member is not always required to be made of a material having a specific gravity larger than that of a material of the base portion. 
     In each of the embodiments, the weight is formed in a rectangular parallelepiped shape, a flat ring-like shape, a rod-like shape, or other shapes. However, the weight may have any geometric shape as long as the weight has a given weight or has a specific gravity larger than that of the base portion, and the weight is in contact with the base portion. As examples of other shapes, there are given a cubic block, a circular plate, a round rod, a pipe, a hexagonal member, an angle bar, a C-shaped steel member, and an angle block. Further, in view of component cost, widely distributed standard items and commercially available items such as a screw, a nut, a shim, a washer, a collar, a ring, and a pin may be directly used as the weight. Further, in terms of installation and maintenance workability, a shim tape having both of a function of the weight and an adhering function may be used as the weight. 
     Further, this invention is not limited to each of the embodiments described above, and this invention includes all the possible combinations of those features. 
     REFERENCE SIGNS LIST 
       1  floor plate,  2  balustrade,  4  skirt guard,  10  step,  15  connector,  20 A- 20 R guide shoe,  21 , 21 A- 21 D base portion,  22 , 22 A- 22 D,  30  weight,  23  leg portion.