Abstract:
Example drive systems for handrails of walkways and moving stairs may comprise a plurality of carriages. In some examples, each carriage may comprise a body with several leading rollers that roll along a guide that defines a handrail path. The carriage may further comprise a locking/release mechanism for selectively coupling the carriage to a drive chain of the handrail. The locking/release mechanism may comprise a hook configured to move between an engagement position wherein the carriage is coupled to the drive chain and a disengagement position wherein the carriage is uncoupled from the drive chain. In some cases, a position of the hook may be controlled by a wheel that travels along a cam profile.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a drive system for handrails of walkways and moving stairs, and more specifically, for the drive of variable speed handrail grips, intended for walkways and stairs that include low-speed end segments and a higher speed intermediate segment, among which the walkway and the handrail grips must move at a variable speed. 
       BACKGROUND ART 
       [0002]    It is usual to find mechanical walkways of the type mentioned above where several segments are defined that act at different speeds such that, according to the direction of operation thereof, the walkway establishes a first boarding zone at a slow speed, an acceleration zone, an intermediate zone at the maximum speed, a deceleration zone and a landing zone at a slow speed. 
         [0003]    There are several solutions available in order to achieve the variable speed required in the acceleration and deceleration zones, including the one proposed in document ES2310465. In said solution, the power is transmitted by a network of chains of rollers from the main drive of the walkway to drive wheels that move the drive chains of each handrail. The chains are in charge of distributing along the walkway, while the variable pitch screw only changes the speed of the carriages when the same are released from the drive chain. 
       DESCRIPTION OF THE INVENTION 
       [0004]    The invention relates to a drive system for handrails of walkways and moving stairs such as the one defined in the set of claims. 
         [0005]    Specifically, the invention is a drive system for handrails of walkways and moving stairs formed by a plurality of carriages, which in turn present a body and a plurality of leading rollers configured to roll along a guide defining a handrail path. The system object of the invention also has locking-release means of the carriage with a drive chain of the handrail, which in turn comprise a wheel and a hook connected to the wheel, and guiding means. 
         [0006]    The wheel is configured to roll along a cam profile to move the locking means between an operative position, wherein the carriage is fixed to the chain, and an inoperative position, wherein the carriage is released from the chain. 
         [0007]    In turn, the hook is configured to move between an engagement position, wherein the carriage is fixed to the chain and moves at the same speed thereof, transmitting the power generated in the motors that passes onto to the drive screws placed in one or more zones of the handrail path, and a disengagement position, wherein the carriage is released from said chain and moves at a variable speed in the acceleration and deceleration segments, not transmitting any power. 
         [0008]    The guiding means are configured to guide a movement of the hook between the engagement position and the disengagement position. 
         [0009]    Particularly, these guiding means have two columns in a guiding plane parallel to the guide. 
         [0010]    The system can also present positioning means, which have a compression spring configured to push the hook towards the engagement position. 
         [0011]    In addition, according to a preferred embodiment of the invention, the system presents three leading rollers arranged to prevent the pitch of the carriage. The form of arrangement of the three rollers is the following, the two first leading rollers aligned parallel to the guide, and the other leading roller not aligned with the first two leading rollers. 
         [0012]    According to a particular embodiment, the body has an L-shaped transversal section formed by a long wing with a vertical orientation and a short wing with a horizontal orientation. 
         [0013]    The long wing with a vertical orientation houses the guiding rollers and drive rollers. These drive rollers have a first drive roller affixed to the body engaged to the drive screw in the zones of the handrail path where said drive screw is placed, allowing the traction of the drive chain when the cam profile defines a locking situation, and the displacement of the carriage according to the movement of the drive screw independently from the drive chain when the cam profile defines a release situation. In addition, the drive rollers have a second drive roller affixed to the body engaged to the drive screw in the zones of the handrail path where said drive screw is placed, thereby avoiding the displacement of the carriage according to any movement opposite to the one defined by the drive screw. 
         [0014]    The short wing with a vertical orientation serves as a rolling track for the drive chain in the acceleration and deceleration segments, where the speeds of said chain and carriage are substantially different. 
         [0015]    By means of the system of the present invention, the power is generated in synchronous motors directly moving the variable pitch screws transmitting the power through the carriages when these are locked to the chain at a maximum speed, the carriages thereby being in charge of distributing the power to the drive chain which in turn moves the rest of the circuit. When the carriage is released from the drive chain, it stops transmitting power and it only changes its speed. 
         [0016]    This new proposal eliminates a large number of mechanical connections, drastically reducing the number of components in order to achieve greater reliability, reduce vibrations and decrease the noise. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    A series of drawings provided in order to better understand the invention and which are expressly related to an embodiment of said invention, presented as a non-limitative example thereof, are very briefly described below. 
           [0018]      FIG. 1  is a perspective of an inner face of a carriage of the system of the invention. 
           [0019]      FIG. 2  is a perspective of an outer face of a carriage of the system of the invention. 
           [0020]      FIG. 3  is an elevated view of a carriage of the system of the invention. 
           [0021]      FIG. 4  is a top view of a carriage of the system of the invention. 
           [0022]      FIG. 5  is an elevated view of the carriage set of the present invention, drive screw and drive chain. 
           [0023]      FIG. 6  is a perspective view with partial tears of the carriage set of the present invention, drive screw and drive chain in its two operative positions, locking and release. 
           [0024]      FIG. 7  is a general schematic view of a preferred embodiment of a handrail circuit with the speed being represented by a dotted line. 
       
    
    
     DETAILED DESCRIPTION OF AN EMBODIMENT 
       [0025]    An embodiment of the invention relates to a drive system for handrails of walkways and moving stairs formed by a plurality of carriages  4 , which in turn have a body  6  and a plurality of leading rollers  7  configured to roll along a guide  5  defining a handrail  1  path, where the guide  5  can be inside of the handrail  1 . 
         [0026]    The carriages  4  present locking/release means with a drive chain  2  of the handrail  1 . 
         [0027]    The locking/release means in turn present a drive wheel  24 , which can be a wheel that rotates freely, configured to roll along a cam profile  25  to move the locking means between an operative position, wherein the carriage  4  is locked to the chain  2 , and an inoperative position, wherein the carriage  4  is released from the chain  2 . 
         [0028]    In addition, the carriages  4  have a hook  12  connected to the drive wheel  24 , which is configured to move between an engagement position and a disengagement position. In the engagement position, the carriage  4  is locked to the chain  2 , and moves at the same speed thereof, which is the maximum speed of the walkway or stair. In addition, it transmits the power generated in the motors, which passes onto the screws  3  placed in one or more zones of the handrail path, and when engaged to the carriage  4 , it makes the carriage  4  transmit the force to the drive chain  2  in order for the drive chain  2  to drive the rest of the carriages  4  of the circuit. 
         [0029]    In the disengagement position, the carriage  4  is released from said chain and moves at a variable speed in the acceleration  31  and deceleration  32  segments, not transmitting any power, and guiding means  10  configured to guide a movement of the hook  12  between the engagement position and the disengagement position. 
         [0030]    According to another characteristics of the invention: 
         [0031]    According to different particular embodiments of the invention, the drive system for handrails of walkways and moving stairs, the guiding means  10  comprise two columns in a guiding plane parallel to the guide  5 . 
         [0032]    In addition, the carriage presents positioning means, which in turn present a compression spring  26  configured to push the hook  12  towards the engagement position. 
         [0033]    Preferably, the carriage  4  has three leading rollers  7  arranged to prevent the pitch of the carriage  4 , thereby preventing the carriage  4  from moving from the front part to the back part, lowering and raising each part alternatively. 
         [0034]    These leading rollers  7  are arranged such that two leading rollers  7  are aligned in a direction parallel to the guide, and a third leading roller  7  is not aligned with the two other leading rollers  7 . 
         [0035]    Particularly, the leading rollers  7  have a horizontal rotation axis. 
         [0036]    According to a particular embodiment, the body  6  has an L-shaped transversal section formed by a long wing with a vertical orientation and a short wing with a horizontal orientation. 
         [0037]    The long wing houses the guiding rollers  7  and drive rollers  8 ,  8 ′, which present a first drive roller  8  and a second drive roller  8 ′. 
         [0038]    The first drive roller  8  is affixed to the body  6  engaged to the drive screw  3  in the zones of the handrail  1  path where said drive screw  3  is placed, allowing the traction of the drive chain  2  when the cam profile  25  defines a locking situation  33 , and allowing the displacement of the carriage  4  according to the movement of the drive screw  3  independently from the drive chain  2  when the cam profile  25  defines a release situation  34 . The second drive roller  8 ′ is affixed to the body  6  engaged to the drive screw  3  in the zones of the handrail  1  path where said drive screw  3  is placed, thereby avoiding the displacement of the carriage  4  according to any movement opposite to the one defined by the drive screw  3 . 
         [0039]    Specifically, this second leading roller  8 ′ prevents the pitch and yaw movement of the carriage  4 . The pitch movement prevented would make the carriage  4  move from the front part to the back part, lowering and raising each part alternatively. The yaw movement prevented would make the carriage  4  move from side-to-side with respect to the direction defined by the handrail path. 
         [0040]    The short wing serves as a rolling track for the drive chain  2  in the acceleration  31  and deceleration  32  segments, where the speeds of said chain  2  and carriage  4  are substantially different. 
         [0041]    According to a particular embodiment of the invention, each one of the carriages  4  can present a grip  30  joined together thereto.