Abstract:
A guide rail ( 14 ) for an elevator system ( 10 ) includes a base ( 20 ) connectable with a wall of a hoistway ( 12 ) of the elevator system ( 10 ) and a web section ( 24 ) connected to and extending from the base ( 20 ). A tip section ( 26 ) is located at an end of the web section ( 24 ) and is operably connectable to an elevator car ( 16 ) of the elevator system ( 10 ). The base ( 20 ), the web section ( 24 ) and the tip section ( 26 ) are formed of one or more thicknesses ( 28 ) of sheet metal material. An elevator system ( 10 ) includes an elevator car ( 16 ) located in a hoistway ( 12 ) and a guide rail ( 14 ) extending along the hoistway ( 12 ) and operably connected to the elevator car ( 16 ) for guiding the elevator car ( 16 ) along the hoistway ( 12 ). The guide rail ( 14 ) is configured such that braking forces applied to the guide rail ( 14 ) by a braking mechanism ( 36 ) successfully reduce the speed of the elevator car ( 16 ) without resulting in failure of the guide rail ( 14 ).

Description:
BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein generally relates to elevator systems. More specifically, the subject disclosure relates to guide rails for elevator cars. 
     Elevator systems typically include an elevator car suspended in a hoistway by a number of suspension ropes. To guide the elevator car in the hoistway, a number of guide rails are arranged in the hoistway, for example, from the top to bottom of the hoistway. The elevator car is connected to the guide rails via one or more guide shoes such that the elevator car follows a path defined by the guide rails as it moves through the hoistway. Further, in some elevator systems, a braking mechanism connected to the elevator car acts on the guide rails to slow and/or stop the elevator car in the hoistway. 
     The typical guide rail is a solid steel T-shaped rail. Such rail configurations are typically utilized because of their ability to withstand buckling and deflection during normal elevator operations and to withstand and loads applied during emergency braking. The typical rails, however, are heavy and bulky, with each rail typically weighing 8 or more pounds per linear foot and are typically installed in 20-foot sections. Installation requires heavy equipment due to the weight of the rails, and is additionally difficult due to the constraints of installing the sections in the confined space of the elevator hoistway. The art would well receive a lighter weight, more easily installed guide rail which can withstand the operational and braking loads of the elevator system. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a guide rail for an elevator system includes a base connectable with a hoistway of the elevator system and a web section connected to and extending from the base. A tip section is located at an end of the web section and is operably connectable to an elevator car of the elevator system. The base, the web section and the tip section are formed of one or more thicknesses of sheet metal material. The guide rail is configured such that braking forces applied to the guide rail by a braking mechanism successfully reduce the speed of the elevator car without resulting in failure of the guide rail. 
     According to another aspect of the invention, an elevator system includes an elevator car located in a hoistway and a guide rail extending along the hoistway and operably connected to the elevator car for guiding the elevator car along the hoistway. The guide rail includes a base connectable with the hoistway, a web section connected to and extending from the base, and a tip section located at an end of the web section and operably connected to the elevator car. The base, the web section and the tip section are formed of one or more thicknesses of sheet metal material. The elevator system includes a braking mechanism operably connected to the guide rail and the elevator car, the guide rail configured such that braking forces applied by the braking mechanism to the guide rail successfully reduce a speed of the elevator car without resulting in failure of the guide rail. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic view of an embodiment of an elevator system; 
         FIG. 2  is a cross-sectional view of an embodiment of a guide rail for an elevator system; 
         FIG. 3  is a cross-sectional view of a tip section of a guide rail for an elevator system; 
         FIG. 4  is a cross-sectional view of another embodiment of a tip section of a guide rail for an elevator system; 
         FIG. 5  is a cross-sectional view of another embodiment of a guide rail for an elevator system; 
         FIG. 6  is a cross-sectional view of a further embodiment of a guide rail for an elevator system; 
         FIG. 7  is a cross-sectional view of yet another embodiment of a guide rail for an elevator system; 
         FIG. 8  is a cross-sectional view of still another embodiment of a guide rail for an elevator system; 
         FIG. 9  is a cross-sectional view of another embodiment of a guide rail for an elevator system; 
         FIG. 10  is a cross-sectional view of yet another embodiment of a guide rail for an elevator system; 
         FIG. 11  is a cross-sectional view of an embodiment of a safety brake mechanism for an elevator system; and 
         FIG. 12  is a schematic illustration of a method of forming a guide rail for an elevator system. 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Shown in  FIG. 1  is an embodiment of an elevator system  10 . The elevator system  10  is located in a hoistway  12  and includes one or more guide rails  14  affixed to the hoistway  12 . The guide rails  14  are connected to an elevator car  16  to guide the movement of the elevator car  16  through the hoistway  12 . As shown in  FIGS. 1 and 2 , in some embodiments, the elevator car  16  includes at least one guide shoe  18  which interfaces with the guide rail  14 . 
     An embodiment of a guide rail  14  is shown in  FIG. 2 . The cross-section is formed from a sheet metal, which may be bent, roll-formed, welded, and/or otherwise manipulated into the final shape. The guide rail  14  of  FIG. 2  is formed from a single piece of sheet metal. In other embodiments, however, the guide rail  14  may be formed of two or more pieces of sheet metal formed into the guide rail  14 . The guide rail  14  includes a base  20  having two base pads  22  configured to rest against the wall of the hoistway  12 . A web  24  extends in one direction from the base  20  into the hoistway  12  toward the elevator car  16 . To enhance stiffness of the guide rail  14 , in a transition area between the base  20  and the web  24 , there is a space  40  between an inner sheet  42  and an outer sheet  44  of material. Either or both of the base  20  and the web  24  comprise multiple layers of sheet metal material such that rail  14  has sufficient stiffness and rigidity sufficient to guide the elevator car  16 . The web  24  extends to a tip section  26 . The tip section  26 , as shown in  FIG. 2 , may have the same dimensional shape as a typical steel guide rail. The tip section  26  includes one or more material thicknesses  28  to form an exterior portion  30  of the tip section and a tip cavity  32  inside the tip section  26 . As shown in  FIG. 2 , the elevator car  16  has a guide shoe  18  including a safety brake  36 . When a condition exists in which the elevator car  16  needs to be stopped, the safety brake  36  is actuated to engage guide rail  14  and stop the elevator car  16 . More specifically, safety brake  36  applies braking forces to the exterior  30  of tip section  26 , in order to stop the elevator car  16 . One or more stiffeners  34  are located in the tip cavity  32  and span at least partially across the tip cavity  32  to stiffen the tip section  26  and allow it to withstand such braking forces. If the tip section  26  is not sufficiently stiff, when braking forces are applied, the tip section  26  could structurally fail, requiring replacement of the guide rail  14 . In some embodiments, such as in  FIG. 2 , the stiffeners  34  may be baffle-shaped. In other embodiments, such as in  FIG. 3 , the stiffeners  34  may be ribs extending toward the sides  38  of the tip section  26 , or as in  FIG. 4 , the stiffeners  34  may comprise loops of material disposed in the tip cavity  32 . In other embodiments, a filler material may be inserted in the tip cavity  32  by injection or other means to add additional stiffness to the tip section. In addition to the exemplary embodiments shown and described herein, many other variations of tip section  26 , with various configurations of stiffeners  34 , also exist that are consistent with the present invention. 
     The embodiment of the guide rail  14  shown in  FIG. 2  is merely exemplary, and other embodiments of guide rail  14  shape are shown in  FIGS. 5-10 . In  FIG. 5 , the guide rail  14  includes a triangular-shaped base  20  from which the web  24  extends to the tip section  26 . The web  24  of the guide rail  14  comprises two material thicknesses  28 , as opposed to the four material thicknesses of the embodiment shown in  FIG. 2 . The base includes a corrugated-shaped base pad  22  to interface with the wall of the hoistway  12 . Referring now to  FIG. 6 , another embodiment includes a flat base  20  with a folded base pad  22 . The web  24  of the guide rail  14  of  FIG. 6  also comprises two material thicknesses  28 . The embodiment of  FIG. 7  includes a triangular base  20 , and a web  24  which comprises four material thicknesses. The tip section  26  includes stiffeners  34  extending into the tip cavity  32 .  FIG. 8  shows is an embodiment in which the tip section  26  does not include a tip cavity  32 , and the web  24  has two material thicknesses  28 . Having the wall-thicknesses  28  side by side in the tip section  26  increases rigidity due to the lack of gap and will therefore withstand braking forces applied thereto. Shown in  FIG. 9  is an embodiment having a base  20  with two base pads  22 , one base pad  22  at each end of the base  20 . The web  24  comprises four material thicknesses, and the tip section  26  includes two stiffeners  34  extending to a tip end  46  of the tip section  26 . 
     Another embodiment of a guide rail  14  formed from a single piece of sheet metal is shown in  FIG. 10 . The guide rail  14  includes a flat base  20  having two base pads  22  configured to rest against the wall of hoistway  12 . The web  24  extends in one direction from the base  20  toward the elevator car  16 . In this embodiment, the web  24  comprises two web legs  58  which define a triangular-shaped web  24 . The tip section  26  comprises three material thicknesses  28  abutting one another with no gaps therebetween, effectively a solid form to withstand braking forces applied thereto. 
     As shown in  FIG. 11 , some embodiments of guide rail  14  may be utilized with a safety brake  36  which engages the web  24  of the guide rail  14 . The brake frame  48  is configured to engage the tip section  26  with a guide shoe  18 . A braking portion  50  extends around the tip section  26  to the web  24 , inboard of the tip section  26 . When desired, the safety brake  36  is engaged and applies braking force to the web  24  to stop the elevator car  16 . Such a safety brake  36  configuration requires less reinforcement of the tip section  26  than that of a typical safety brake, in which the safety brake  36  engages the tip section  26 . Further, the unique brake frame  48  configuration prevents removal of the brake frame  48  (and the elevator car  16 ) from the guide rail  14  in the event of seismic movement of the building, or similar circumstances. It is prevented because the clearance of the brake frame  48  to the web  24  is smaller than a width of the tip section  26 . 
     Forming the guide rail  14  from sheet metal allows for a lighter weight guide rail  14  when compared to a typical steel guide rail that has sufficient stiffness and rigidity. A lighter weight guide rail  14  makes for easier and safer installation of the guide rail  14  in the hoistway  12 . Further, as shown in  FIG. 12 , the guide rail  14  may be formed onsite, even inside the hoistway  12 . In one embodiment, a forming machine  52  including rollers  54 , welders (not shown) and other components necessary to form the guide rail  14  from a flat piece of sheet metal, is located in the hoistway  12 . A sheet metal stock  56  is fed into a first end  60  of the forming machine  52 , and is rolled, formed, punched, and/or welded into a guide rail  14  having a desired cross section. The finished guide rail  14  exits a second end  62  of the forming machine  52  and, in some embodiments, may be positioned in the hoistway  12  and/or secured thereto by the forming machine  52 . In some embodiments, the forming machine  52  may be configured to travel along the hoistway  12  as the guide rail  14  is formed. For example, the forming machine  14  may form a desired length of guide rail  14  which is positioned in the hoistway  12  and secured thereto. The forming machine  52  then is urged along the length of rail  14  via internal or external means, and forms a second length of guide rail  14 . This process can be continued until the entire guide rail  14  is completed. Utilizing on-site forming of the guide rail  14  allows for simplified installation process, and in some cases, a single unitary guide rail  14  extending the entire length of the hoistway  12  can be formed. Such a guide rail  14  having no seams between discrete guide rail  14  segments eliminates mismatches that occur between segments and results in smoother and quieter operation of the elevator system  10 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.