Patent Publication Number: US-2010126073-A1

Title: Actuator for elevator doors, elevator door arrangement including same and methods

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 61/117,878, filed Nov. 25, 2008, the disclosure and teachings of which are incorporated herein, in their entireties, by reference thereto. 
    
    
     FIELD OF THE INVENTION 
     This invention generally relates to mechanisms for actuating doors and more particularly elevator doors. 
     BACKGROUND OF THE INVENTION 
     Elevator doors typically have two doors that move relative to one another to open and close an elevator compartment. Unfortunately, prior elevator doors have complicated linkages to open and close the doors. This complicated linkage arrangement results in the door arrangement being a primary source for maintenance calls for elevators. 
     Further, it is desirable to have the doors operate smoothly because many people have a fear of elevators and that they may fail. However, when the doors on an elevator do not close smoothly, even though they do not generally affect the actual motion of the elevator, many elevator riders become apprehensive of the mechanical safety of the elevator as a whole. 
     The present invention relates to improvements over the current state of the art. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments of the present invention relate to a new and improved actuator for a double door elevator door. More particularly, the present invention relates to a high-precision, simplified actuator for a double door elevator door. However, embodiments of the invention may be applied to other double door arrangements and a door may merely be a shield such as in a manufacturing operation. 
     In a first implementation of the invention, a double door actuation system is provided. The actuation system includes a base frame, a drive motor, first and second guide rails and first and second rail support arrangements. The drive motor is mounted to the base frame and includes a pinion gear rotatable about an axis of rotation. The first guide rail includes opposed first and second raceways and a first gear rack. The first gear rack engages the pinion gear on a first side of the axis of rotation. The second guide rail includes opposed third and fourth raceways and a second gear rack. The second gear rack engages the pinion gear on a second side of the axis of rotation, opposite the first side. In this arrangement, rotation of the pinion gear simultaneously drives the first and second guide rails in opposite directions parallel to a drive axis. The first and second rail support arrangements are mounted to the base frame and support the first and second guide rails, respectively. The rail support arrangements maintain a substantially constant lateral location of the guide rails in a direction perpendicular to both the drive axis and axis of rotation to maintain a substantially constant mesh between the pinion gear and first and second gear racks. 
     In one embodiment, the first rail support arrangement is a first group of guide rollers engaging the first and second raceways and the second rail support arrangement is a second group of guide rollers engaging the third and fourth raceways. In a more preferred arrangement, each of the first and second groups of guide rollers includes at least three guide rollers, a first guide roller of the first rail support arrangement engaging the first raceway and second and third ones of the first rail support arrangement engaging the second raceway, a first guide roller of the second rail support arrangement engaging the third raceway and second and third ones of the second rail support arrangement engaging the fourth raceway. 
     In another arrangement, each of the first and second groups of guide rollers includes a fourth guide roller, the fourth guide roller of the first rail support arrangement engaging the first raceway and the fourth guide roller of the first rail support arrangement engaging the third raceway. 
     To provide precision actuation of attached doors and to prevent wear, friction, and backlash between the pinion and the first and second gear racks, in one embodiment, the first and second raceways have a parallelism per foot of less than or equal to 0.005 inches relative to a pitch diameter of the first gear rack and the third and fourth raceways have a parallelism per foot of less than or equal to 0.005 inches relative to a pitch diameter of the second gear rack. Even more preferably, the first and second raceways have a parallelism per foot of less than or equal to 0.001 inches relative to a pitch diameter of the first gear rack and the third and fourth raceways have a parallelism per foot of less than or equal to 0.001 inches relative to a pitch diameter of the second gear rack. In view of this parallelism, it is desired to have a parallelism per foot between the pitch diameters of the two gear racks  152  of less than or equal to 0.005 inches and even more preferably of less than or equal to 0.002 inches. Alternatively, the parallelism between the two pitch diameters of the opposed gear racks  152  could be measured as a variation between the two locations measured in a plane including the axis of rotation of the pinion gear  128  that extends perpendicularly to the drive axis  126 . This parallelism could be quantified as an instantaneous variation between any two portions of the gear racks  152  that align with this plane including the rotational axis of the pinion gear  128  as they are driven back and forth by drive motor  104 . 
     The parallelism measurements can be taken from a hypothetical reference point defined by the raceways or actual points of the raceways themselves. 
     To provide for cheaper construction, the first and second guide rails include first and second base rails with the first and second rear racks being mounted to the first and second base rails. Further yet, the guide rails may include first, second hardened rails mounted to the first base rail and providing the first and second raceways, respectively and third and fourth hardened rails mounted to the second base rail and providing the third and fourth raceways. 
     The raceways preferably provide lateral support to a cooperating structure such as a guide roller such that the guide roller does not move laterally relative to the corresponding raceway. This is typically done by providing a convex or concave profile to the raceways. In some embodiments, the raceways may have a convex or concave V-shape. Alternatively, the raceway profiles can have a gothic arch or merely be provided by an arcuate groove or a convex curve. 
     In one embodiment, the first and second raceways face away from one another and pass through the first rail support arrangement and the third and fourth raceways face away from one another and pass through the second rail support arrangement. 
     In an alternative embodiment, the first and second raceways face one another and the first rail support arrangement passes between the first and second raceways and the third and fourth raceways face one another and the second rail support arrangement passes between the third and fourth raceways. 
     To facilitate easy adaptation to various size pinion gears for operations that require more or less torque, the frame member in some embodiments includes a horizontal top plate to which the motor is attached and first and second sidewalls extending from the top plate in parallel spaced relation, the first and second rail support arrangements being mounted to the first and second sidewalls, respectively, the pinion gear being equally laterally interposed between the first and second sidewalls. In such an arrangement, the parallel spacing between the first and second sidewalls is adjustable relative to one another to accommodate varying sized pinions. Further yet, the first and second sidewalls may be adjustably connected to the top plate. 
     In another aspect, the invention provides a door assembly including an actuator including one or more of the features above in combination with a plurality of doors operably coupled to the guide rails. 
     In yet another aspect, the invention provides a method of controlling a pair of doors comprising; 1) simultaneously engaging a first guide rail connected to a first door and engaging a second guide rail connected to a second door with a pinion gear; 2) simultaneously driving the doors in opposite directions and away from one another; 3) the first guide rail including opposed first and second raceways and a first gear rack, the first gear rack engaging the pinion gear on a first side of an axis of rotation of the pinion gear; 4) the second guide rail including opposed third and fourth raceways and a second gear rack, the second gear rack engaging the pinion gear on a second side of the axis of rotation, opposite the first side, such that rotation of the pinion gear simultaneously drives the first and second guide rails in opposite directions parallel to a drive axis; and 5) maintaining a substantially constant mesh between the pinion and first and second gear racks. 
     Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a perspective illustration of a double door actuation arrangement according to the teachings of the present invention; 
         FIG. 2  is a perspective partial illustration of the double door actuation arrangement of  FIG. 1 ; 
         FIG. 3  is a bottom partial illustration of the double door actuation arrangement of  FIG. 1 ; 
         FIG. 4  is a perspective illustration of the double door actuation arrangement of  FIG. 1  and a double door that may be actuated by the double door actuation arrangement; 
         FIG. 5  is a perspective partial illustration of a rail support arrangement supporting a guide rail of the double door actuation arrangement of  FIG. 1 ; 
         FIG. 6  is a perspective partial illustration of the rail support arrangement of  FIG. 5 ; 
         FIG. 7  is an end view illustration of a guide rail of the double door actuation arrangement of  FIG. 1 ; 
         FIG. 8  is an end view of an alternative embodiment of a guide rail that can be used in a double door actuation arrangement according to an embodiment of the present invention; and 
         FIG. 9  is a partial end view illustration of the double door actuation arrangement of  FIG. 8 . 
     
    
    
     While the invention will be described in connection with certain embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  illustrate an embodiment of a double door actuation arrangement  100  according to the teachings of the present invention. The double door actuation arrangement  100  acts to drive two doors in opposite parallel directions using a single rotational input. In a preferred embodiment, the double door actuation arrangement  100  utilizes a double rack and pinion drive mechanism to drive the doors in opposite directions. 
     The double door actuation arrangement  100  generally includes a base frame  102 , a drive motor  104 , first and second guide rails  106 ,  108  and first and second rail support arrangements  110 ,  112 . 
     The base frame  102  generally includes a top plate  114  and two downward depending and parallel spaced apart sidewalls  116 ,  118 . The sidewalls  116 ,  118  are preferably adjustably secured to the top plate  114  to permit adjusting the width W of the spacing therebetween (see  FIG. 3 ) to accommodate different rack and pinion arrangements. As illustrated in  FIG. 1 , the top plate  114  includes a plurality of elongated slots  117  that receive cap screws  119  that permit laterally adjusting the spacing of sidewalls  116 ,  118  (e.g. width w). 
     The base frame  102  may also include a plurality of standoffs  120  extending laterally between and to maintain structural integrity and the parallel relationship between the sidewalls  116 ,  118 . The base frame  102  also includes a bearing support plate  122  interposed between the sidewalls  116 ,  118  (see  FIGS. 2 and 3 ). 
     Returning to  FIG. 1 , the motor  104  is affixed to the base frame  102  and more particularly to top plate  114 , which may also be referred to as a motor mounting plate. The motor  104  is operably coupled to guide rails  106 ,  108  such that operation of the motor  104  drives guide rails  106 ,  108  in opposite directions along drive axis  126 . 
     With reference to  FIG. 2 , the drive motor  104  is operably coupled to pinion gear  128  by a shaft extension  130 . The shaft extension  130  is supported on an end opposite drive motor  104  by a bearing  132  mounted to bearing support plate  122 . This arrangement prevents flexure in the shaft extension  130  to maintain a constant mesh between the pinion gear  128  and the guide rails  106 ,  108 . 
     With reference to  FIG. 4 , each of the guide rails  106 ,  108  include door dogs  134  that fit into and or otherwise engage doors  136 ,  138  to transfer loading between the guide rails  106 ,  108  and doors  136 ,  138 . Doors  136 ,  138  are vertically supported and laterally guided by door track  140 . However, other arrangements for guiding the doors  136 ,  138  can be provided. Each guide rail  106 ,  108  preferably include positive hard stops  142  at ends opposite the ends that include dogs  134 . The positive hard stops prevent the guide rails  106 ,  108  from being over extended. Typically, positive hard stops  142  will interfere with or abut an edge or side of the sidewalls  116 ,  118 . 
       FIGS. 5 and 6  illustrate the support arrangement for the guide rails. For simplification, only a single one of the support arrangements will be described, but both guide rails  106 ,  108  are typically, but not necessarily, identically supported. 
     The first rail support arrangement  110  is generally provided by a plurality of guide rollers  141 - 144 . The plurality of guide rollers  141 - 144  are mounted to sidewall  116  to maintain their spatial relationship. As illustrated in  FIG. 5 , the guide rail  106  passes through the first rail support arrangement  110 . More particularly, guide rollers  141 ,  142  ride on an upper raceway  146  while guide rollers  143 ,  144  are spaced apart from guide rollers  141 ,  142  and ride on lower raceway  148  (not shown in  FIGS. 5 and 6  but shown in  FIG. 3 ). 
     While the first rail support arrangement  110  of the illustrated embodiment includes four (4) guide rollers  141 - 144 , other arrangements can be used. However, at least three guide rollers are desired to prevent the guide rail from pivoting relative to the guide rollers. When using three guide rollers rather than four, two guide rollers would engage one raceway while a single guide roller would engage the other raceway. However, in this arrangement, the single guide roller is preferably axially interposed between the other two guide rollers to prevent pivoting of the guide rail. 
     Further, while the illustrated embodiment has the guide rail  106  pass through the first rail support arrangement  110  and particularly between guide rollers  141 - 144  as illustrated in  FIG. 5 , other arrangements are contemplated. More particularly, rather than having the raceways  146 ,  148  face away from one another, as illustrated in  FIG. 7 , the raceways  246 ,  248  could face one another, such as illustrated in the embodiment of  FIG. 8 . In this embodiment, the rail support arrangements would actually pass between the raceways  246 ,  248  of the guide rail  206 . 
     Further, while illustrated raceways are rounded or V-shaped, alternative raceways may be provided that include concave profiles and that could provide gothic arches or other raceway profiles. Further, while the raceways are illustrated as being provided by hardened rails mounted to a base rail, such as base rail  150  (see  FIG. 7 ), other embodiments could have the raceways formed directly into the base rail material. 
     As illustrated in  FIGS. 5 and 7 , the guide rails  106  include a gear rack  152  mounted to the base rail  150 . The pinion gear  128  meshes with the gear racks  152  to transfer rotational motion of drive motor  104  into linear motion of the guide rails  106 ,  108  parallel to drive axis  126  (see  FIG. 3 ). 
     As illustrated in  FIG. 9 , guide rails  106 ,  108  are on opposite sides of pinion  128  such that as pinion  128  rotates angularly about axis of rotation  154 , the two guide rails  106 ,  108  move parallel to one another in opposite directions. 
     The guide rails preferably have a precise parallelism between the raceways  146 ,  148  and the gear rack  152  to maintain a substantially constant mesh between the pinion gear  128  and the gear racks  152 . Preferable guide rails and methods of forming such guide rails are provided in “GUIDE RAIL HAVING BASE RAIL AND GEAR RACK, METHOD OF MAKING SAME, GUIDE ASSEMBLY INCLUDING SAME” having U.S. Patent Application No. 61/117,795 which is incorporated herein in its entirety by reference thereto. 
     More particularly, and with reference to  FIG. 7 , the parallelism between the raceways  146 ,  148  and the pitch diameter  160  of the gear racks  152  is less than or equal to 0.005 inches per foot along the length of the guide rail  106  and more preferably less than or equal to 0.002 inches per foot length and even more preferably less than or equal to 0.001 inches per foot length. This parallelism can be measured as the variation in distance D 1  defined between a plane  162  defined by two reference points defined by the raceways  146 ,  148  and the pitch diameter  160  of the gear rack  152 . In the illustrated embodiment, the reference points defined by the raceways  146 ,  148  are provided by a theoretical intersection points  161 ,  163  of surfaces  164 ,  165  and  166 , 167  of raceways  146 ,  148 , respectively. Plane  162  represents a theoretical lateral position of the guide rollers as they travel along raceways  146 ,  148 . 
     However, the parallelism could be measured from other locations as well to establish that the raceways  146 ,  148  provide the desired parallelism relative to the gear rack. This parallelism requirement maintains a desired mesh between the pinion gear  128  and gear racks  152 . 
     More particularly, with reference to  FIG. 9 , precise parallelism between raceways  146 ,  148  and gear racks  152  is desirable because of the fixed relationship of the guide rail support arrangements  110 ,  112  and pinion gear  128  during operation. Because the pinion gear  128  has a fixed position relative to the guide rail support arrangements  110 ,  112 , and particularly the guide rollers thereof, any variation in the relative position of raceways  146 ,  148  relative to gear rack  152  directly affects the mesh with pinion gear  128 , and particularly the gap, therebetween. Variations in this gap will cause premature wear of the pinion gear  128  and gear racks  152  as well as excessive backlash and noise. 
     The lateral position of the gear rack  152  relative to the pinion gear  128  is provided by the interaction of the guide rollers  141 - 144  with raceways  146 ,  148 . 
     By having high parallelism within the guide rails  106 ,  108 , the rail supports can maintain a substantially constant lateral location of the guide rails  106 ,  108 , and particularly gear racks  152  along an axis  184  that is perpendicular to both the drive axis  126  and the axis of rotation  154  of the pinion gear  128 . 
     In a further embodiment, the gear rack  152  may be integrally formed into the base rail  150  by standard machining techniques by way of example only by hobbing. However, the desired parallelism can be maintained by using a reference point relating to the raceways can be used to locate the machining/hobbing process. 
     All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.