Patent Publication Number: US-11390490-B2

Title: Cantilevered climbing elevator

Description:
BACKGROUND 
     Elevator systems have proven useful for carrying passengers among various levels within a building. There are various types of elevator systems. For example, some elevator systems are considered hydraulic and include a piston or cylinder that expands or contracts to cause movement of the elevator car. Other elevator systems are traction-based and include roping between the elevator car and a counterweight. A machine includes a traction sheave that causes movement of the roping to achieve the desired movement and positioning of the elevator car. Hydraulic systems are generally considered useful in buildings that have a few stories while traction systems are typically used in taller buildings. 
     Each of the known types of elevator systems has features that present challenges for some implementations. For example, although traction elevator systems are useful in taller buildings, in ultra-high rise installations the roping is so long that it introduces appreciable mass and expense. Sag due to roping stretch and bounce of the elevator car are other issues associated with longer roping Additionally, longer roping and taller buildings are more susceptible to sway and drift, each of which requires additional equipment or modification to the elevator system. 
     SUMMARY 
     An illustrative example embodiment of an elevator includes an elevator car frame. A drive mechanism is situated near only one side of the elevator car frame. The drive mechanism includes at least one rotatable drive member that is configured to engage a vertical surface near the one side of the elevator car frame, selectively cause movement of the elevator car frame as the rotatable drive member rotates along the vertical surface, and selectively prevent movement of the elevator car frame when the drive member does not rotate relative to the vertical surface. A biasing mechanism urges the rotatable drive member in a direction to engage the vertical surface. At least one stabilizer is situated near the one side of the elevator car frame and is configured to prevent the elevator car frame from tipping away from the vertical surface. 
     In an embodiment having one or more features of the elevator of the previous paragraph, the at least one rotatable drive member comprises a wheel and a motor supported at least partially within the wheel. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the at least one rotatable drive member comprises a second wheel. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the second wheel includes a motor supported at least partially within the second wheel. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the biasing mechanism comprises at least one beam supported for movement in a first direction to urge the at least one rotatable drive member in the direction to engage the vertical surface and the at least one beam moves in the first direction based upon a force in a second, different direction. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the first direction is horizontal and the second direction is vertical. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the force is based on a load on the elevator car frame. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the at least one rotatable drive member comprises two drive wheels situated to engage oppositely facing vertical surfaces, the at least one beam comprise two beams, each of the two beams has a first end and a second end, the beams are respectively associated with one of the drive wheels, the beams are supported for pivotal movement relative to the elevator car frame in response to the force, the first ends of the beams move toward each other in response to an increase in the force, and the second ends of the beams move away from each other in response to the increase in the force. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the biasing mechanism includes an actuator portion that moves in the second direction in response to a change in the force, the actuator portion moves in response to the increase in the force to cause movement of the first ends of the beams toward each other, and the actuator portion moves in response to a decrease in the force to allow movement of the first ends of the beams away from each other. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator portion moves along the second direction. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator portion includes an angled surface that has a first profile along a portion of the angled surface and a second profile along a second portion of the angled surface, the first profile includes a first angle that is steeper than a second angle of the second portion, and the second portion of the angled surface causes movement of the first ends of the beams in response to the force being above a preselected threshold. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the second profile includes a curved surface. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs and comprising a vertical support member that includes the vertical surface, the vertical support member includes at least one reaction surface that is transverse to the vertical surface; and the stabilizer is received against the at least one reaction surface. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the vertical support comprises an I-beam having a web and a flange at each end of the web, the web defines the vertical surface, and at least one of the flanges defines the at least one reaction surface. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the stabilizer comprises at least one roller that is received against the at least one reaction surface on the at least one of the flanges. 
     An embodiment having one or more features of the elevator of any of the previous paragraphs includes a cabin supported on the elevator car frame, a sensor that provides an output indicating a load in the elevator car, and a processor that determines the load in the elevator car based on the output of the sensor. The biasing mechanism comprises an actuator that is controlled by the processor to change a force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on a change in the load in the elevator car. 
     In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator increases the force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on an increase in the load in the elevator car and decreases the force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on a decrease in the load in the elevator car. 
     The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates selected portions of an example embodiment of an elevator system. 
         FIG. 2  schematically illustrates selected features of the embodiment of  FIG. 1  viewed from underneath the elevator car. 
         FIG. 3  schematically illustrates an example rotatable drive member useful, for example, with the embodiment shown in  FIG. 1 . 
         FIG. 4  schematically illustrates an example configuration of a biasing mechanism for urging rotatable drive members in a direction to engage a vertical surface. 
         FIG. 5  schematically illustrates an example actuator portion of the biasing mechanism shown in  FIG. 4 . 
         FIG. 6  schematically illustrates another example embodiment of a biasing mechanism. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates selected portions of an elevator system  20 . An elevator car frame  22  supports a cab  24 . A drive mechanism  26  is supported by the elevator car frame  22 . An elevator controller (not illustrated) controls operation of the drive mechanism  26  to move or park the elevator car frame  22  and cab  24  as needed to provide elevator service to passengers. The drive mechanism  26  includes at least one rotatable drive member  28  that is configured to engage a vertical surface. The rotatable drive member  28  selectively causes vertical movement of the elevator car frame  22  and the cab  24  as the rotatable drive member  28  rotates and moves along the vertical surface. The rotatable drive member  28  maintains a desired vertical position of the elevator car frame  22  when the rotatable drive member  28  remains stationary and does not rotate. As can be seen in  FIG. 2 , for example, the illustrated example embodiment includes two rotatable drive members  28 . 
     In the illustrated example embodiment, the drive mechanism  26  and the rotatable drive members  28  are situated near the bottom of the elevator car frame  22 . This arrangement takes advantage of the structural rigidity at the lower portion of an elevator car frame. 
     The example embodiment includes a structural member  30  in the form of an I-beam that includes a web  32  and flanges  34 . The web  32  defines a vertical surface that the rotatable drive members  28  engage. In the illustrated example embodiment, the rotatable drive members  28  engage opposite sides of the web  32 . The rotatable drive members  28  engage the web  32  with sufficient force to achieve traction for controlling vertical movement and position of the elevator car frame  22  and the cab  24 . 
     In the illustrated example embodiment, the structural member  30  is secured by mounting brackets  36  to one side of a hoistway  38 . Other embodiments include a structural member that is made as part of the hoistway  38  or a corresponding portion of the building in which the elevator system  20  is installed. There are a variety of ways of providing a vertical surface  32  that can be engaged by one or more rotatable drive members  28  for purposes of propelling and supporting the elevator car frame  22  and cab  24 . 
     The drive mechanism  26  is situated on only one side of the elevator car frame  22 . This results in a cantilevered arrangement of the elevator car frame  22 . A stabilizer  40  is provided near the one side of the elevator car frame  22  to prevent the elevator car frame  22  from tipping away from the structural member  30 . In this example, the stabilizer  40  includes at least one roller that engages a surface on at least one of the flanges  34  of the I-beam structural member  30 . In some embodiments, the stabilizer  40  includes rollers configured like guide rollers on known elevator systems. 
       FIG. 3  illustrates an example rotatable drive member  28 . A wheel or tire  42  provides the engagement surface for engaging the vertical surface  32  to achieve sufficient traction for controlling movement of the elevator car frame  22 . A motor  44  in this example embodiment is situated within the rotatable drive member  28 , which provides a compact arrangement of components that is capable of achieving the necessary torque to cause desired movement and stable positioning of the elevator car frame  22  based on engagement with the vertical surface  32 . 
       FIG. 4  schematically illustrates a biasing mechanism  50  that urges the rotatable drive members  28  into engagement with the example vertical surface  32 . The biasing mechanism  50  includes beams  52  that are associated with drive member supports  54 . In this example, the drive member supports  54  and the beams  52  are situated for pivotal movement relative to the elevator car frame  22  ( FIG. 1 ) about pivots  56 . In this example, first ends of the beams  52  are situated near the drive member supports  54  while second ends of the beams  52  are distal from the rotatable drive members  28 . 
     At least one actuator  60  selectively changes a distance D between the second ends of the beams  52  to change the engagement force F N  with which the rotatable drive members  28  engage the vertical surfaces of the web  32  of the I-beam structural member  30 . The actuator  60  changes the distance D in response to a change in a load in the elevator cab  24 . The load in the cab  24  imposes a downward force F L . The actuator  60  urges the rotatable drive members  28  in a direction to engage the vertical surfaces on the web  32  of the I-beam structural member  30 . In the illustrated example embodiment, the movement of the beams  52  is in a first direction, which is horizontal, and the force associated with the load in the elevator cab  24  is in a second direction, which is vertical. In the illustrated example embodiment, the first direction is perpendicular to the second direction. 
     The actuator  60  facilitates changing the amount of engagement force or normal force F N  to accommodate differences in load in the elevator car  24 . Such an arrangement facilitates maintaining adequate traction between the drive mechanism  26  and the structural member  30  without maintaining forces or conditions that would tend to introduce additional wear on the components of the drive mechanism  26  or the structural member  30 , for example. 
       FIG. 5  illustrates an example arrangement of an actuator  60 . In this example, a wedge-shaped actuator portion  62  moves in response to the force F L  caused by the load in the elevator cab  24 . Downward movement (according to the drawing) of the wedge-shaped actuator portion  62  causes sideways and outward movement (according to the drawing) of intermediate members  64  against the bias of springs  66 . As the intermediate members  64  move outward, they urge the nearby second ends of the beams  52  to spread apart increasing the distance D shown in  FIG. 4 . 
     In this example embodiment, the wedge-shaped actuator portion  62  engages a ramped surface  68  on the intermediate members  64 . The outer surface of the actuator portion  62  and the ramped surfaces  68  are coated with a low friction material in some embodiments. The wedge-shaped actuator portion  62  includes an angled surface that has a first profile  70  along a portion of the angled surface and a second profile  72  along another portion of the angled surface. The first profile  70  includes a steeper angle than an angle of the second profile  72 . Additionally, the second profile  72  includes a curvature. The second profile  72  reduces the frictional load associated with engaging the angled surfaces  68  as the force F L  increases. The second profile  72  compensates for an increase in the co-efficient of friction by reducing the effect of the normal force at the interface of the second profile  72  and the angled surfaces  68  under higher loads in the elevator cab  24 . 
     As can be appreciated from  FIGS. 4 and 5 , as the force F L  increases, the actuator  60  increases the distance D, which results in the rotatable drive members  28  moving toward the vertical surfaces on the web  32  of the I-beam structural member  30 . In other words, the actuator  60  increases the engagement force between the rotatable drive members  28  and the vertical surfaces  32  based upon an increase in the load in the elevator cab  24 . An increased engagement force provides the appropriate amount of traction for achieving desired movement of the elevator car frame  22  and for parking the cab  24  at a desired landing. 
     As shown in  FIG. 4 , a counterbalancing mechanism  80  provides a bias for urging the beams  52  back toward a default position corresponding to a minimum amount of normal force F N  applied by the rotatable drive members  28  to the vertical surfaces  32 . the minimum normal force F N  is useful for conditions such as an empty elevator cab  24 . As the load in the elevator cab  24  decreases, a spring  74  ( FIG. 5 ) urges the wedge-shaped actuator portion  62  in an upward direction (according to the drawing). Under those conditions, the counterbalancing mechanism  80  urges the first ends of the beams  52  apart and decreases the distance D between the second ends of the beams  52 . 
       FIG. 6  schematically illustrates another example embodiment in which a sensor  90  provides an output indicating the load in the elevator car  24  to a processor  92 . An actuator  94 , such as an electric linear actuator, changes a position of the rotatable drive members  28  relative to the structural members  30  as schematically shown by the arrows  96  to alter the engagement force based on changes in the load as indicated by the sensor  90 . The processor  92  controls the actuator  94  to achieve a desired engagement force corresponding to the current load in the elevator car  24 . 
     The illustrated example embodiments include various features that can be advantageous. For example, situating the drive mechanism  26  on only one side of the elevator car frame  22  leaves more room in the hoistway  38  to accommodate a larger sized elevator cab  24  or a variety of car configurations. Additionally, it is possible to position a door  100  ( FIG. 2 ) of the elevator car on any of the three remaining sides of the elevator cab  24  other than the one that the drive mechanism  26  is situated near. In addition to utilizing hoistway space more efficiently, less material is required with a drive mechanism near only one side of the elevator car frame. Reducing the required amount of materials reduces the costs of an elevator system. 
     Other features of example embodiments include reduced installation time, which is due for example to the requirement for only one structural member on only one side of the elevator car. Additionally, the structural member may be more strategically placed where load rated attachment points are more easily or more effectively accommodated inside the hoistway. 
     Another feature of example embodiments is that it becomes more straightforward to incorporate more than one elevator car in a single hoistway. Multiple cars can use the same structural member without complicated arrangements to avoid interference between the operative components of the drive mechanisms for each car. Some embodiments include the ability to transfer elevator cars among different hoistways. The United States Patent Application Publications US 2109/0077636 and US 2109/0077637 each show ways of transferring elevator cars among hoistways and having more than one car in a hoistway. The teachings of those two published applications are incorporated by reference into this description. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.