Patent Publication Number: US-10781076-B2

Title: Elevator buffer system

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This patent application is a US National Stage Application of PCT/IB2015/001553, filed Aug. 17, 2015, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to an elevator system, and more particularly, to an elevator buffer system. 
     Elevator systems include an enclosed car for transporting passengers and/or cargo vertically in a hoistway. The car typically includes four sidewalls, a ceiling, and a floor or platform. For structural support and vertical movement, the car is typically supported by a cradle or frame engaged directly to a driving apparatus (e.g. cabled, linear motors, hydraulic, etc.). Elevator systems may also include buffers arranged at the floor or bottom of the elevator system hoistway designed as a safety measure and/or to minimize damage to the elevator system, and/or passenger discomfort, during unusual events. More specifically, the buffers are constructed to experience an elevator system car strike should the car overrun the lowermost stopping position in the hoistway. 
     Known buffer arrangements may also include isolation pads located about the periphery of the platform and generally between the platform and the lower frame. Should an elevator system car overrun the lowermost limit, the buffer strikes the frame and at least a portion of the force may be transmitted to the car platform through the peripheral isolation pads. Unfortunately, the distribution of force throughout the platform is limited, leading to less than ideal frame optimization. Further enhancements of strike force distribution and structural support relative to buffer arrangements is desirable. 
     SUMMARY 
     An elevator system according to one, non-limiting, embodiment includes a buffer; a frame; a platform spaced from the frame; and a pre-compressed pad device disposed between the frame and the platform and engaged to one of the frame and the platform and spaced from the other of the frame and the platform. 
     Additionally to the foregoing embodiment, the frame is spaced above the buffer and the platform is spaced above the frame. 
     In the alternative or additionally thereto, in the foregoing embodiment, the elevator system is configured to adapt at least one of a non-strike position with the pre-compressed pad device being spaced from the other of the frame and the platform, a mid-strike position with the pre-compressed pad device being in contact with the other of the frame and the platform, and a full-strike position with the pre-compressed pad device being further compressed against the other of the frame and the platform. 
     In the alternative or additionally thereto, in the foregoing embodiment, the system includes at least one isolation pad disposed between and in contact with the frame and the platform, wherein the at least one isolation pad is substantially uncompressed when in the non-strike position, is partially compressed when in the mid-strike position, and is more compressed when in the full-strike position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the at least one isolation pad includes first and second isolation pads and the pre-compressed pad device is spaced between the first and second isolation pads. 
     In the alternative or additionally thereto, in the foregoing embodiment, the first and second isolation pads are each in continuous contact with the frame and the platform. 
     In the alternative or additionally thereto, in the foregoing embodiment, the pad device is engaged to the frame. 
     In the alternative or additionally thereto, in the foregoing embodiment, the pre-compressed pad device includes a resiliently compressible pad, a plate, and a member extending in a direction of strike, and wherein the member slideably extends through the frame and is engaged to the plate with the compressible pad being pre-compressed between the frame and the plate. 
     In the alternative or additionally thereto, in the foregoing embodiment, the resiliently compressible pad and the first and second isolation pads are made of the same material. 
     In the alternative or additionally thereto, in the foregoing embodiment, the compressible pad and the first and second isolation pads have a substantially equivalent geometry when in a non-compressed state. 
     In the alternative or additionally thereto, in the foregoing embodiment, the frame includes a first side in contact with the resiliently compressible pad and an opposite second side, and the member includes a shaft engaged to the plate and extending through the frame and an enlarged head engaged to the shaft and in biased contact with the second side when in the non-strike position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the shaft extends through an isolation washer of the pre-compressed pad device disposed between the second side and the enlarged head. 
     In the alternative or additionally thereto, in the foregoing embodiment, as the system moves from the mid-strike position to the full-strike position, the pre-compressed pad device is further compressed by a first distance that is substantially equal to a second distance that the at least one isolation pad is further compressed. 
     In the alternative or additionally thereto, in the foregoing embodiment, as the system moves from the non-strike position to the mid strike position, the at least one isolation pad is compressed by a third distance that is substantially equal to a gap between the pre-compressed pad device and the other of the frame and the platform when in the non-strike position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the platform is generally the floor of an elevator system car and the frame supports the car for vertical movement. 
     A method of operating an elevator system according to another, non-limiting, embodiment includes striking of a frame against a buffer; moving of the frame toward a platform; compressing of peripheral isolation pads located between the frame and the platform; further moving the frame toward the platform; further compressing of the peripheral isolation pads; and compressing of a central pad. 
     Additionally to the foregoing embodiment, the peripheral isolation pads and the central pad are resiliently compressible. 
     In the alternative or additionally thereto, in the foregoing embodiment, the central pad is pre-compressed. 
     In the alternative or additionally thereto, in the foregoing embodiment, the method includes distributing an impact force substantially evenly across the platform. 
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. However, it should be understood that the following description and drawings are intended to be exemplary in nature and non-limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiments. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG. 1  is a perspective view of an elevator system having a buffer system and with parts broken away to show internal detail as one, non-limiting, exemplary embodiment of the present disclosure; 
         FIG. 2  is a schematic of the buffer system illustrated in a non-strike position; 
         FIG. 3  is a schematic of the buffer system illustrated in a mid-strike position; 
         FIG. 4 , is a schematic of the buffer system illustrated in a full-strike position; 
         FIG. 5  is an enlarged view of the buffer system taken from circle  5  in  FIG. 2 ; 
         FIG. 6  is an enlarged view of the buffer system taken from circle  6  in  FIG. 3 ; and 
         FIG. 7  is an enlarged view of the buffer system taken from circle  7  in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an elevator system  20  of the present disclosure is illustrated, and may include a car  22 , a counterweight  24 , a drive device  26 , a rope  28 , a structural frame or sling  30  and a buffer system  32 . The car  22  may carry passengers or other objects and is constructed to move substantially vertically in a hoistway  34  of the elevator system  20 . Boundaries of the hoistway  34  may be defined by a stationary structure or building  36  that may utilize and house the elevator system  20 . The drive device  26  may be housed in a machine room  38  of the building  36  located generally above the hoistway  34 , and may include an electric motor  40  that rotates a sheave  42 . The rope  28  is wrapped about the sheave  42  and extends between the car  22  and the counterweight  24  such that when the drive device  26  receives a command signal to raise the car  22 , the sheave  42  rotates in a first direction that lowers the counterweight  24  as the car  22  rises, and vice-versa. The counterweight  24  generally weighs about the same as the car  22  when at about fifty percent capacity, and thus reduces the work output requirements of the drive device  26 . 
     Referring to  FIGS. 1 and 2 , the elevator buffer system  32  is constructed to stop a descending car  22  that travels beyond a normal lower limit, and softens the force with which the car  22  runs into a pit area during emergencies. During normal operation, the elevator buffer system  32  may also isolate the car  22  from vibrations and noise providing a more comfortable ride for passengers. The elevator buffer system  32  may include a buffer  44 , a horizontal portion  46  of frame  30 , a platform  48 , a plurality of isolation pads  50 , and a pre-compressed pad device  52 . The buffer  44  is generally positioned in a pit area  54  of the hoistway  34  and projects upward from a bottom floor  56  in the pit area  54 . The horizontal portion  46  of frame  30  may generally extend across the bottom of the car  22  and may be part of the structural frame or sling  30  that generally wraps about the car and facilitates connection to the rope  28  and guide rails  58  in the hoistway  34 . The platform  48  may generally be the floor of the car  22  and is spaced above the frame portion  46  by the plurality of isolation pads  50  distributed about a periphery or outer edge  60  of the platform  48 . The pre-compressed pad device  52  is also located between the frame portion  46  and the platform  48  and may be centrally positioned with respect to the platform periphery  60  (i.e., spaced horizontally between the isolation pads  50 ). 
     During normal elevator system  20  operation, the isolation pads  50  provide a degree of vibration and noise isolation between the frame portion  46  of the sling  30  and the platform or floor  48  of the car  22  thus contributing toward passenger comfort. The isolation pads  50  may extend vertically between and may be in continuous contact with the platform  48  and the frame portion  46 . 
     Referring to  FIG. 5  and during normal elevator system  20  operation, the pad device  52  is pre-compressed and remains capable of further compression at a pre-specified point during a buffer strike. The device  52  may include a plate  62 , a pad  64  that may be resiliently compressible, and an elongated member  66 . The member  66  (i.e., two illustrated) may include a shaft  68  projecting outward from an enlarged head  70  of the member  66 . When assembled and during normal elevator system  20  operation, the pad  64  that may be centrally located with respect to the isolation pads  50  is compressed between the plate  62  and an upward facing side  72  of the frame portion  46 . The shaft  68  of the member  66  is engaged to the plate  62  at one end and projects slideably through the frame portion  46  to the enlarged head  70 . The enlarged head  70  is generally biased against an opposite second side  74  of the frame portion  46  via the resilient force of the pre-compressed pad  64 . The device  52  may further include isolation washers  76  located between the second side  74  of the frame portion  46  and the enlarged head  70  of the member  66 , and through which the shaft  68  extends. It is further contemplated and understood that the elevator system  20  may include several buffers  44  and several pad devices  52  associated with any one elevator car  22 . 
     The elevator buffer system  32  is configured to move through and between a non-strike position  80  (see  FIGS. 2 and 5 ) that generally exists during normal operation of the elevator system  20 , a mid-strike position  82  (see  FIGS. 3 and 6 ) that generally occurs upon striking of the frame portion  46  with the buffer  44 , and a full-strike position  84  (see  FIGS. 4 and 7 ) that generally occurs with the continued downward momentum of the car  22 . During elevator system  20  operation and prior to a buffer strike, the elevator buffer system  32  is in the non-strike position  80  such that the isolation pads  50  are generally not compressed except for the weight of the car  22  and the passengers. Also, the plate  62  is spaced from the platform  48  by a gap or distance (see arrow  86  in  FIG. 5 ), the enlarged heads  70  are generally biased against the isolation washer  76  that is biased against the second side  74  of the frame portion  46 , and the buffer  44  is spaced below the frame portion  46 . 
     Upon a buffer strike in a strike direction (see arrow  85  in  FIG. 3 ), the elevator buffer system  32  moves from the non-strike position  80  toward the mid-strike position  82 . During this movement, the second side  74  of the frame portion  46  contacts the buffer  44  causing the buffer  44  to resiliently compress vertically. Continued downward motion of the car  22  causes the force (see arrow  88  in  FIG. 6 ) placed upon the buffer  44  to increase whereupon the isolation pads  50  begin to compress vertically as the platform  48  moves closer to the plate  62  of the pre-compressed pad device  52  and the frame portion  46 . During this period, the pre-compressed pad  64  of the device  52  does not compress further and the enlarged heads  70  remain biased against the second side  74  of the frame portion  46 . 
     With continued downward motion (i.e., the strike direction  85 ) of the car  22 , the elevator buffer system  32  enters the mid-strike position  82  when the isolation pads  50  are vertically compressed by a distance (see arrow  90  in  FIG. 6 ) substantially equal to the gap  86  measured when the buffer system  32  is in the non-strike position  80 . At this point, the plate  62  is in initial contact with the platform  48 , the isolation pads  50  and the buffer  44  may continue to compress, and the pre-compressed pad  64  begins to compress further as the enlarged heads  70  of the member  68  move downward and away from the second side  74  of the frame portion  46 . The contact of the plate  62  with the platform  48  has the effects of evenly distributing the impact force across the platform  48 , stiffening the frame portion  46 , and enables improved structural optimization. The total distance (see arrow  92  in  FIG. 7 ) that the isolation pad  50  moves as a result of compression is generally equal to the gap  86  (see  FIG. 5 ) plus a distance (see arrow  94  in  FIG. 7 ) that the enlarged head  70  moves away from the washer  76  (i.e., bottom side  74  of the frame portion  46 ). 
     The buffer  44  may be any variety of buffers including coiled spring buffer, resilient material buffer (e.g., cellular polyurethane) and hydraulic or oil buffers. The isolation pads  50  and the pre-compressed pad  64  may be made of the same resiliently compressible material, such as, for example, rubber. The isolation pad  50  and the pre-compressed pad  64  (i.e., in the uncompressed state), may have substantially the same equivalent load versus deflection characteristics. To simplify structural calculations, the isolation pads  50  may be of the same size and geometric shape as the pad  64  when not compressed. It is further contemplated and understood that various components may be reversed. For example, the pre-compressed pad device  52  may be carried by the platform  48  and spaced from the frame portion  46  when the buffer system  32  is in the non-strike position  80 . 
     While the present disclosure is described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present disclosure. In addition, various modifications may be applied to adapt the teachings of the present disclosure to particular situations, applications, and/or materials, without departing from the essential scope thereof. The present disclosure is thus not limited to the particular examples disclosed herein, but includes all embodiments falling within the scope of the appended claims.