Abstract:
An elevator system includes one or more rails fixed in a hoistway and an elevator car configured to move through the hoistway along the one or more rails. The system includes one or more braking systems having one more braking surfaces secured to the elevator car and frictionally engageable with one or more rails of the elevator system. One or more actuators are operably connected to the one or more braking surfaces configured to urge engagement and/or disengagement of the one or more braking surfaces with the rail to stop and/or hold the elevator car during operation of the elevator system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to elevator systems. More specifically, the subject disclosure relates to braking systems for elevators. 
         [0002]    Elevator systems are driven by a motor, referred to as a machine, which drives a lifting means, typically ropes or belts, attached to an elevator car. The speed and motion of the elevator car are controlled by a variety of devices scattered throughout the elevator system which are installed and adjusted individually. For example, a brake at the machine is used to stop and hold the elevator car during normal and emergency operation. A governor is located at an idler pulley in the hoistway or pit or machine room to detect over speed of the elevator car when it is in motion. Position reference systems on the elevator car and in the hoistway are used to gather data on the position of the elevator car, and safeties mounted on the elevator car are utilized to stop the car in the hoistway in the event of an emergency. Installation and setup of all of these separate devices is costly and time consuming. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    According to one aspect of the invention, a braking system for an elevator system includes one or more braking surfaces secured to an elevator car and frictionally engageable with a rail of an elevator system. One or more actuators are operably connected to the one or more braking surfaces configured to urge engagement and/or disengagement of the one or more braking surfaces with the rail to stop and/or hold the elevator car during operation of the elevator system. 
         [0004]    According to another aspect of the invention, an elevator system includes one or more rails fixed in a hoistway and an elevator car configured to move through the hoistway along the one or more rails. The system includes one or more braking systems having one or more braking surfaces secured to the elevator car and frictionally engageable with one or more rails of the elevator system. One or more actuators are operably connected to the one or more braking surfaces configured to urge engagement and/or disengagement of the one or more braking surfaces with the rail to stop and/or hold the elevator car during operation of the elevator system. 
         [0005]    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 
         [0006]    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: 
           [0007]      FIG. 1  is a schematic of an embodiment of an elevator system; 
           [0008]      FIG. 2  is a perspective view of an embodiment of a brake for an elevator system; 
           [0009]      FIG. 3  is a perspective view of an embodiment of a brake for an elevator system connected to a safety; 
           [0010]      FIG. 4  is a perspective view of a brake for an elevator system with an integrated safety; 
           [0011]      FIG. 5  is a perspective view of an embodiment of a wedge-driven brake for an elevator system; 
           [0012]      FIG. 6  is a perspective view of an embodiment of a brake for an elevator system using rollers; 
           [0013]      FIG. 7  is a perspective view of an embodiment of a brake for an elevator system having brake arms; 
           [0014]      FIG. 8  is a perspective view of another embodiment of a brake for an elevator system having brake arms; 
           [0015]      FIG. 9  is a perspective view of yet another embodiment of a brake for an elevator system having brake arms; 
           [0016]      FIG. 10  is a plan view of another embodiment of an elevator braking system; 
           [0017]      FIG. 11  is a side view of the elevator braking system of  FIG. 10 ; and 
           [0018]      FIG. 12  is an end view of the elevator braking system of  FIG. 10 . 
       
    
    
       [0019]    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 
       [0020]    Shown in  FIG. 1  is an embodiment of an elevator system  10 . The elevator system  10  includes a motor for driving the elevator system, known as a machine  12 . The machine  12  drives a lifting means, for example, one or more belts or ropes, hereinafter referred to as “ropes”  14  over one or more pulleys to urge motion of an elevator car  16  up and/or down in a hoistway  18 . One or more rails  20 , typically at least two rails  20 , are located in the hoistway  18  and the elevator car  16  is positioned in the hoistway  18  such that the rails  20  guide the motion of the elevator car  16 . A braking system, generally shown at  22 , is secured to the elevator car  16 . The braking system  22  interacts with the rails  20  to slow and/or stop the elevator car  16  during normal operation of the elevator  10 , for example, stopping at a floor to load and/or unload passengers. Further, some embodiments of the braking system  22  include the function of a traditional emergency brake, or safety, to slow and/or stop movement of the elevator car  16  in the event of an emergency, for example, the elevator car  16  exceeding a predetermined speed, or in the event of a power failure of the elevator  10 . 
         [0021]    Referring to  FIG. 2 , shown is an embodiment of a braking system  22 . The braking system  22  is secured to the elevator car  16  via, for example a support  24  with the various components of the braking system  22  secured thereto. The braking system  22  includes a caliper  26  having one or more brake pads  28 . The brake pads  28  are movable to engage the rail  20  between the brake pads  28  and one or more braking pads  30  on the opposite side of the rail  20 . In some embodiments, the brake pads  28  are movable via a braking actuator  32 . The braking actuator  32  may be, for example, a solenoid, a linear motor, or other type of actuator. The braking actuator  32  includes one or more braking actuator plungers  34  extending toward one or more brake pad pins  36 . When the braking actuator  32  is energized, such as during operation of the elevator  10 , the braking actuator plungers  34  are drawn into the braking actuator  32 . When it is desired to activate the braking system  22 , the braking actuator  32  is de-energized. One or more plunger springs  38  bias the braking actuator plungers  34  outwardly, away from actuator  32 , urging them into an extended position. As the braking actuator plungers  34  move outwardly, the braking actuator plungers  34  come into contact with the brake pad pins  36  and urge the brake pad pins  36  toward the rail  20 . The brake pad pins  36  in turn move the brake pads  28  into contact with the rail  20  and slow and/or stop movement of the elevator car  16  relative to the rail  20  by frictional forces between the brake pads  28  and the rail  20  and between the braking pads  30  and the rail  20 . To deactivate the brake, the braking actuator  32  is energized, drawing the braking actuator plungers  34  into the actuator  32 , overcoming the bias of the plunger springs  38 , thus allowing the brake pads  28  to move away from the rail  20 . 
         [0022]    In some embodiments, the braking actuator plunger  34  is split into two or more braking actuator plungers  34  extending from a single braking actuator  32 . Each braking actuator plunger  34  can interact independently with a separate brake pad  28 , providing redundancy in the braking system  22 . 
         [0023]    As shown in  FIG. 3 , in one embodiment, a braking block  30  may be connected to a safety  40 . Many aspects of the braking system shown in  FIG. 2 , such as plunger  34 , plunger springs  38 , and brake pad pins  36 , are included in this embodiment as well. In this example, a safety actuator  42  includes a safety plunger  44  which retains the braking block  30  when the safety plunger  44  is extended toward the braking block  30 , for example, into a plunger hole  46  in the braking block  30 . The braking block  30  is connected to the safety  40  via a trip rod  48 . When it is desired or necessary to engage the safety  40  with the rail  20 , the safety actuator  42  is energized, thus drawing the safety plunger  44  away from the braking block  30 . This allows the braking block  30  to translate along the rail  20  through friction with the rail  20 . Translation of the braking block  30  along the rail  20  pulls the trip rod  48  which activates the safety  40 . When the brake pads  28  are released, gravity will reset the braking block  30 , trip rod  48 , and safety  40 . The safety actuator  42  is de-energized to retain the braking block  30  in the home position. 
         [0024]    Referring to  FIG. 4 , in some embodiments, the brake pads  28  and safety  40  may be combined into a single unit. This embodiment includes the braking actuator  32  to move the brake pads  28  toward the rail  20  by mechanical interactions between de-energized actuator  32 , plungers  34 , and pins  36  similar to those described above with respect to  FIGS. 2 and 3 , and the braking blocks  30 . If it is desired to engage the safety  40 , a safety actuator  42  is activated which allows braking block  30  to move along the rail  20 , forcing a safety block  52  to travel along a direction parallel to a slot  54  into contact with the rail  20 , where the rail  20  will be held between the safety block  52  and a safety wedge  56 . 
         [0025]    Shown in  FIG. 5  is an embodiment utilizing a braking wedge  64  housed within a caliper  26  to move the brake pad  28  into contact with the rail  20 . The braking wedge  64  is connected to the braking actuator  32  via the braking actuator plunger  34 . The plunger spring  38  biases the braking wedge  64  in an engaged direction. The braking wedge  64  abuts a complimentary brake pad wedge  66  to which the brake pad  28  is fixed. When the braking actuator  32  is de-energized, the plunger spring  38  urges the braking wedge  64  away from the braking actuator  32 , which pushes the brake pad wedge  66  and the brake pad  28  into contact with the rail  20  where frictional forces between the brake pad  28  and rail  20  and between the braking pad  30  and the rail  20  slow or stop the elevator car  16  (not shown in  FIG. 5 ). In some embodiments, the caliper  26  is slidably connected to the support  24  by one or more support pins  68 . Shown in  FIG. 6 , rather than braking pads  28 , some embodiments may use braking rollers  70  to slow or stop the elevator car  16 . 
         [0026]    Referring to  FIG. 7 , some embodiments of the braking system  22  may include two or more brake arms  58  secured to the support  24  which is secured to the elevator car  16  (not shown in  FIG. 7 ). The brake arms  58  are pivotably secured to the support  24  at arm pivots  60 . Each brake arm  58  includes a brake pad  28  which, when the braking system  22  is activated, moves toward the rail  20  and slows or stops the movement of the elevator car  16  relative to the rail  20  by frictional forces between the brake pads  28 , one or more braking pads  30  secured to the support  24 , and the rail  20 . An arm spring  62  extends between the brake arms  58  and biases the brake pads  28  toward the rail  20 . A braking actuator  32  (alternatively one actuator could be attached to each arm) is located between the brake arms  58  with a braking actuator plunger  34  connected to each brake arm  58 . During operation of the elevator  10 , the braking actuator  32  is energized, drawing the braking actuator plungers  34  inwardly and thus rotating the brake arms  58  around the arm pivots  60  such that the brake pads  28  move away from the rail  20 . When it is desired to activate the braking system  22 , the braking actuator  32  is de-energized and the arm spring  62  forces the brake arms  58  to rotate about the arm pivots  60  (as shown by arrows “A”) so that the brake pads  28  contact the rail  20  (as shown by arrow B) and slow or stop the elevator car  16 . 
         [0027]    Another embodiment is shown in  FIG. 8 . In this embodiment, the brake arms  58  are located two on either side of the rail  20 . When the braking actuator  32  is energized, the braking actuator plunger  34  (not shown) overcomes the force of arm spring  62  and rotates the brake pads  28  away from the rail  20  and away from each other. When the braking actuator  32  is de-energized, the arm spring  62  rotates the braking arms  58  about the arm pivots  60  and brings the brake pads  28  into contact with the rail  20  to slow or stop the elevator car  16 . To provide redundancy, multiple braking arms  58  may be provided at each side of the rail  20 , which in some embodiments may be coupled to multiple braking actuators  32  and/or multiple arm springs  62 . 
         [0028]      FIG. 9  illustrates another embodiment of braking system  22  where braking arms  58  are arranged substantially along the rail  20 , and generally vertically disposed. The braking actuator plunger  34  extends between the braking arms  58  and, when the actuator (not shown) is energized, overcomes the bias of arm springs  62  which are connected to, for example, the support  24  such that the braking arms are pivoted away from the rail  20  and brake pads  28  do not contact the rail  20 . When the braking actuator is de-energized, the arm springs  62  urge rotation of braking arms toward the rail  20 , which in turn pushes the brake pads  28  into contact with the rail  20 . To disengage the brake pads  28  from the rail  20 , the braking actuator is energized, so that plunger  34  urges the braking arms  58  to rotate in a direction shown by arrows A around arm pivots  60 , which in turn moves the brake pads  28  away from the rail  20 . 
         [0029]    In yet another embodiment illustrated in  FIGS. 10-12 , a pivot spring  80  extends through the braking arms  58  at the pivot  60 . The pivot spring  80  is preloaded to prevent movement of the brake arms  58  along a pivot spring axis  82  during normal operation of the elevator system  10 . In such conditions, the braking system  22  engages the rail  20  when the braking actuator  24  is de-energized, thereby allowing the braking arms  58  to rotate about the pivot  60  so the brake pads engage the rail  28 . If the speed of the elevator car (not shown) exceeds a desired limit, the braking forces applied by the de-energizing of the braking actuator  24  may not be sufficient to stop the elevator car. In such cases, friction between the rail  20  and the brake pads  28  will result in forces overcoming the preload of the pivot spring  80 , and allow movement of the brake arms  58  along the pivot spring axis  82 . As a result, the brake pads  28  engage with braking wedges  84 , the braking wedges  84  configured to force the brake pads  28  closer to the rail  20  resulting in an addition of braking force to stop the elevator car. 
         [0030]    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.