Patent Publication Number: US-2012023824-A1

Title: Automatic door opener

Description:
This application claims benefit of priority under 35 U.S.C. §119(e) to the filing date of to U.S. Provisional Application No. 61/368,910, as filed on Jul. 29, 2010, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The invention relates to automatic door openers such as may be used to open doors in public settings. Such door openers typically comprise a motorized mechanism that moves the door between an open and closed position upon actuation by a user. 
     SUMMARY OF THE INVENTION 
     A door opener for opening a door having an external surface comprises a screw mounted for rotary motion and a carriage mounted on the screw such that rotation of the screw causes motion of the carriage along the screw. A motor rotates the screw. An actuator arm has a first end and a second end, where the actuator arm is operatively connected to the carriage such that movement of the carriage causes the actuator arm to move between a retracted position where the door is closed and an extended position where the door is open. The first end of the actuator arm is in contact with but not connected to the external surface of the door such that the first end of the actuator arm rides over the external surface of the door. 
     The door opener may further comprise a bearing on the carriage that resists rotation of the carriage about the axis of screw when the screw is rotated. The bearing may comprise a roller bearing received in a slot. The carriage may be connected to a first end of a linkage at a first pivot where the opposite end of the linkage is pivotably connected to the actuator arm at a second pivot. The second pivot may be positioned at the first end of the actuator arm. The first end of the actuator arm may comprise a bearing surface that contacts the external surface of the door. The bearing surface may comprise a roller that contacts the external surface of the door. The motor may be actuated in response to a signal from a sensor. A controller may control activation of the motor in response to the signal. The controller may activate the motor for a predetermined period of time. The sensor may be a touchless pad. A limit switch may control the movement of the carriage. The first end of the actuator arm may comprise a bearing surface that contacts the external surface of the door where the exterior surface may comprise a wear plate attached to the door. A door closer mechanism may move the door when the actuator arm is moved from the extended position to the retracted position to return the door to the closed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a back perspective view of one embodiment of the door opener of the invention in the closed position. 
         FIG. 2  is a back perspective view of the embodiment of the door opener of  FIG. 1  in a partially open position. 
         FIG. 3  is a back perspective view of the embodiment of the door opener of  FIG. 1  in a fully open position. 
         FIG. 4  is a front perspective view of the embodiment of the door opener of  FIG. 1  in the closed position. 
         FIG. 5  is a top view of the embodiment of the door opener of  FIGS. 1 and 2  in the open position. 
         FIG. 6  is a perspective view of the embodiment of the door opener system of  FIG. 1 . 
         FIG. 7  is a top view of another embodiment of the door opener of the invention. 
         FIG. 8  is a top view of yet another embodiment of the door opener of the invention. 
         FIG. 9  is a perspective view of still another embodiment of the door opener of the invention. 
         FIG. 10  is a top view of yet another embodiment of the door opener of the invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     The invention relates to the touch-free opening of a door such as a restroom door. The automatic door opener described herein may be used with standard size interior doors, although it has utility with any door. In the door opener of the invention an actuator arm contacts and moves over the surface of the door, but is not attached to the door, such that the door may be opened manually if desired. As a result, the door opener provides automatic and manual operation of the door and, in the event of a power failure or other failure in the unit, the door remains operational. The automatic door opener provides an affordable solution for a touch-free exit/entrance and has particular use in away-from-home applications such as restrooms. Touch-free operation in such environments eliminates potential points for cross-contamination between users. 
     The automatic door opener may comprise an actuator arm that pushes open the door. In one embodiment the actuator arm is connected to a linkage that is in turn connected to a carriage that runs along a drive screw. In one “pull-type” embodiment, one end of the actuator arm is pulled in a first direction to move the opposite end of the arm in a second direction to an extended position to open the door. In one “push-type” embodiment the actuator arm is pushed to the extended position to open the door. The drive screw may be rotated by a geared motor. The free end of the actuator arm is not connected to the door. A bearing or roller, mounted at the free end of the arm, rides along an exterior surface of the door such that the door can be opened manually or automatically. 
     The drive mechanism uses a sliding linear bearing or a roller bearing and slot arrangement to prevent the carriage from rotating about the screw and to control the linear motion of the carriage along the axis of the screw. The bearing also resists the twisting forces generated by the applied loads on the drive from the door. 
       FIGS. 1 through 5  show a first embodiment of the automatic door opener of the invention. This embodiment is a “pull-type” design where the first end of the actuator arm is pulled by the drive mechanism in a first direction to move the opposite end of the actuator arm in the opposite direction to the extended position. The pull-type design minimizes size requirements of the unit and is able to handle the load requirements to open a door. 
     The opener  1  comprises a housing  2  mounted adjacent to a door such that the front of the housing  2   a  and actuating arm  20  faces the door. In the illustrated embodiment the device is shown with housing covers removed to reveal the internal drive mechanism of the opener. In actual use the mechanism may be covered by a removable cover  9  as shown in  FIG. 6  to isolate the drive mechanism from the external environment and to provide a more pleasing aesthetic appearance. As shown in  FIG. 5 , the door  3  and opener  1  are arranged such that the door swings away from the front  2   a  of housing  2  between the closed, dashed-line position and the open solid-line position. The housing  2  may be mounted to the top of a door jamb, a ceiling or other structure adjacent the face of the door. 
     The housing  2  supports a drive screw  6  comprising threads that is supported at each end in bearings  8  such that the screw  6  may rotate about its longitudinal axis. The screw  6  extends along the back of the housing  2  and is rotated by a reversible geared motor  10 . 
     A carriage  12  is mounted on the screw  6  and engages the screw threads such that rotation of the screw  6  causes the carriage  12  to move along the length of the screw  6 . The screw  6  is rotated in a first direction to move the carriage  12  toward one end  6   a  of the screw and is rotated in the opposite direction to move the carriage  12  toward the opposite end  6   b  of the screw  6 . The carriage  12  includes a roller or bearing  15  that is received in a slot  18  formed in the bottom wall  2   b  of housing  2  such that that it resists rotation of the carriage  12  about the axis of screw  6  when the screw is rotated and maintains the orientation of the carriage  12  relative to the screw thread  6  as the carriage  12  traverses the length of the screw  6 . The bearing  15  also resists the twisting forces applied to the drive mechanism caused by the applied loads from the door. 
     The carriage  12  is connected to a first end  14   a  of linkage  14  at a pivot  16  such that the linkage  14  can rotate relative to the carriage  12 . In one embodiment the carriage  12  is formed with an upper flange  13  spaced from a lower flange  19  a distance sufficient to receive the first end  14   a  of linkage  14  therebetween. A pivot pin  17  extends between and is supported by the flanges  13  and  15  and extends through a through hole formed in the first end  14   a  of linkage  14  such that the linkage  14  may freely pivot relative to the carriage  12 . The roller or bearing  15  may be supported on the bottom side of the flange  19 . 
     The opposite end  14   b  of the linkage  14  is pivotably connected to a first end  20   a  of the actuating arm  20  at pivot  22  such that the arm  20  can rotate relative to the link  14 . In one embodiment the arm  20  is formed with an upper flange  23  spaced from a lower flange  25  a distance sufficient to receive the second end  14   b  of linkage  14  therebetween. A pivot pin  27  extends between and is supported by the flanges  23  and  25  and extends through a through hole formed in the second end  14   b  of linkage  14  such that the linkage may freely pivot relative to the actuator arm  20 . The arm  20  is pivotably connected to the housing  2  at a pin  26  that is located between the ends  20   a  and  20   b  of arm  20 . The opposite free end  20   b  of the arm  20  extends through a slot  28  formed in the front  2   a  of housing  2  such that the arm  20  can be extended from the housing through slot  28  upon actuation of the motor  10 . The end  20   b  of arm  20  comprises a roller, low friction surface, ball bearings or other similar bearing surface  30  that contacts an exterior surface  3   a  of the door  3  to push on and slide across the exterior surface of the door and swing the door open about door hinges  5 . The exterior surface  3   a  may be the surface of the door, a metal plate attached to the door to provide a wear surface or other surface attached to the door. A standard return spring  39  may be provided on the door  3  to return the door to the closed position upon retraction of arm  20  and to maintain the door in contact with the surface  3   a  during extension and retraction of arm  20 . 
     The motor  10  and controller  21  are connected to a source of electrical power P and to a sensor such as a touchless pad  32  ( FIG. 6 ). Touchless pad  32  comprises an emitter/receiver that detects reflected light when a user places his or her hands in the light path. The emitter/receiver is disposed such that the light is projected downwardly along the wall rather than perpendicular to the wall. In one embodiment the light is projected at about a 15 degree angle to vertical such that the light is approximately projected 2-6 inches from the wall or other surface on which the sensor  32  is mounted. By projecting the light vertically in close proximity to the wall the sensor is not inadvertently activated by a person walking past the sensor. Rather, the user must place a hand adjacent to the wall to activate the sensor. The power source P may be a battery, a hard wire connection to a buildings power grid, a plug and socket connection or the like. When a user activates the touchless pad  32 , such as by moving their hand close to the pad, the sensor activates motor  10  to open the door as will be described. The sensor  32  transmits a signal to controller  21  and controller  21  transmits a signal to motor  10  that activates the motor. The controller  21  may be a control board, PLC controller, microprocessor or the like. The signal may be transmitted from the sensor to the controller by a hard wire connection (as shown), radio signal, or other wireless signal or the like. While a wall mounted touchless pad  32  is shown, the system may be activated using any suitable sensor such as a floor mat, infra red detector or the like but a sensor that does not require that the user to touch the device by hand is preferred. A manually operated switch  34  may be provided to deactivate the system. Indicator lights  35  may also be provided to indicate faults and or operation of the automatic door opener. The range of motion of the arm between the fully opened position and fully closed position may be controlled by using a stepper motor, limit switches  31 ,  33  or the like. 
     In operation a user activates sensor  32  by moving their hand close to, but not touching, the touchless pad. Upon sensing the user, the sensor  32  transmits a signal to controller  21 . The controller determines if the door is closed by limit switches  31 ,  33 . If limit switch  31  is closed the arm is in the retracted position and the door is in the closed position. Controller  21  transmits a signal to activate motor  10  to initiate operation of the door opener. Motor  10  rotates screw  6  to move carriage  12  along the length of screw  6  toward the end  6   a  of screw  6  in the direction of arrow A ( FIG. 5 ). As the carriage  12  moves along screw  6  it moves the first end  14   a  of linkage  14  in the same direction A. Linkage  14  is free to rotate relative to carriage  12  to accommodate the arc of travel of the end  20   a  of arm  20  as arm  20  rotates about pivot  26 . As the linkage  14  moves in the direction of arrow A, the first end  20   a  of arm  20  is “pulled” causing the arm  20  to rotate about pin  26  in the direction of Arrow B such that the distal free end  20   b  of arm  20  is rotated away from housing  2 . The bearing surface  30  contacts the external surface  3   a  of door  3  and pushes against and rides along surface  3   a  as the arm  20  is extended to move the door to the open position. The force generated by motor  10 , linkage  14  and arm  20  is great enough to overcome the spring force of spring  39  and the weight of the door and move the door to the open position. In one embodiment the peak torque to initially set a 100 lb, 34 inch door in motion is 398 lbf.in (45 Nm) and for a 200 lb, 48 inch door is 850 lbf.in (96 Nm). Arm  20  rotates door  3  about hinges  5  in the direction of arrow C to open the door. When carriage  12  reaches the end of travel it contacts limit switch  33 . Limit switch  33  transmits a signal to controller  21  to stop motor  10  and halt the movement of arm  20  and door  3 . Alternatively, a stepper motor may be used where a controller counts rotation of the screw  6  or of the output shaft of motor  10  and stops rotation of the motor when the count reaches a predetermined value corresponding to the end of motion of the carriage. Other mechanisms for detecting or determining the end of travel of the carriage or arm may also be used. 
     The arm  20  remains in the extended position to hold the door  3  in the open position for a predetermined period of time as set in controller  21  allowing the person to pass through the doorway. Upon expiration of the predetermined period of time the controller transmits a signal to actuate the motor  10 . Motor  10  is reversed causing the carriage  12  and linkage  14  to move toward end  6   b  of screw  6  (opposite arrow A). Movement of linkage  14  causes arm  20  to retract back toward housing  2  (opposite arrow B) allowing the door to move to the closed position (opposite arrow C). When carriage  12  reaches the end of travel it contacts limit switch  31 . Limit switch  31  transmits a signal to controller  21  to stop motor  10  and halt the movement of arm  20 . The motor is stopped by limit switch  31  when the carriage reaches end  6   b  of screw  6  and arm  20  is in the fully retracted position. In one embodiment the door comprises a separate door closer mechanism  39  connected between door  3  and the door frame  37  or other structure that operates to move the door  3  to the closed position upon retraction of arm  20 . The door closer mechanism  39  may comprise a hydraulically dampened spring or other similar device. The separate door closer mechanism  39  resists the opening of the door and pulls the door  3  against the bearing surface  30  as the arm  20  is extended during opening of the door to maintain contact between the exterior surface  3   a  of door  3  and bearing surface  30 . The resistance force provided by door closer mechanism  39  provides for controlled opening of the door such that the arm  20  does not swing the door open in an uncontrolled manner. When the arm  20  is retracted allowing the door to close the door will close at the speed allowed by the door closer mechanism  39 . For example the arm  20  may be retracted relatively quickly such that the arm is retracted in 4 seconds while the door closer mechanism may limit closing of the door to a slower speed such that the door closes in 5 seconds. 
     To open the door, a person may either activate the sensor for automatic operation or the user may simply push the door to open the door manually. Because the door is not connected to the door opener manual operation of the door is unaffected by the door opener. 
     The controller  21  may also be used to provide a safety feature to prevent the automatic opening of a blocked door. The controller detects the amount of current drawn by the motor to move the door to the open position. If the amount of current exceeds a predetermined maximum amount of current needed to open a freely movable door, the motor is reversed to prevent the continued opening of the door against an unanticipated load. 
       FIG. 7  shows another embodiment of the automatic door opener. The opener has a housing  202  mounted adjacent a door such that the front of the housing and actuating arm  220  face the door. The door is arranged such that it swings away from the front of housing  202  as previously described. The housing  202  may be mounted to the top of a door jamb, a ceiling or other structure. Motor  210  drives a sector gear  212  via a transmission such as a gear reducer  215 . The sector gear  212  is connected to actuator arm  220  via linkage  214 . Arm  220  is connected to housing  202  at pivot  226 . Actuation of motor  210  rotates gear  212  to move linkage  214  to rotate arm  220  to the extended position about pivot  226 . Reversing motor  210  rotates actuator arm  220  to the retracted position where door  3  is closed. Alternatively, the actuator arm  220  may be connected directly to the gear  212  without an intermediate linkage  214 . The opener of  FIG. 7  may be used with the sensor, controller, power source, return spring and limit switches/stepper motor as described above to control the motion of arm  220 . 
       FIG. 8  shows another “pull-type” drive mechanism showing the opener with the actuator arm  320  in the fully extended open position. The opener has a housing  302  mounted adjacent a door such that the front of the housing  302   a  and actuating arm  320  face the door. The door is arranged such that it swings away from the front  302   a  of housing  302  as previously described. The housing  302  may be mounted to the top of a door jamb, a ceiling or other structure. A screw  306  comprising threads is mounted for rotation in housing  302 . The screw  306  is rotated by a geared motor  310 . A carriage  312  is mounted on the screw  306  such that rotation of the screw  306  causes the carriage  312  to move along the length of the screw. The screw  306  is rotated in a first direction to move the carriage toward one end  306   a  of the screw and is rotated in the opposite direction to move the carriage toward the opposite end  306   b  of the screw  306 . The carriage  312  is connected to a slider  315  that is received in a track  318  supported by the housing  302  to guide and support the carriage as it moves along screw  306 . 
     The carriage  312  is connected to a linkage  314  at a pivot connection  316 . The opposite end of the linkage  314  is pivotably connected to a first end  320   a  of the actuating arm  320  at pin  322  such that the arm  320  can rotate relative to the linkage  314 . The arm  320  is pivotably connected to the housing  302  at pin  326  that is located at a point of arm  320  between ends  320   a  and  320   b . The opposite end  320   b  of the arm  320  extends through a slot formed in the front  302   a  of housing  302  such that the arm  320  can be extended from the housing upon actuation of the motor  310 . The end  320   b  of arm  320  comprises a roller or other similar bearing surface  330  that contacts an external surface of the door to push on the face of the door and swing the door open about door hinges. The opener of  FIG. 8  may be used with the sensor, controller, power source, return spring and limit switches/stepper motor as described above to control the motion of arm  320 . 
       FIG. 9  shows an embodiment of a push-type mechanism. The opener has a housing  402  mounted adjacent a door such that the front of the housing and actuating arm  420  face the door. The door is arranged such that it swings away from the front of housing  402  as previously described. The housing  402  may be mounted to the top of a door jamb, a ceiling or other structure. The housing  402  supports a screw  406  comprising threads. The screw  406  is rotated by a geared motor  410 . The screw  406  is angled relative to the retracted or closed position of the arm  420  and the motor  410  is set perpendicular to the screw  406 . Motor  410  may also be disposed in-line with screw  406 . A carriage  412  is mounted on the screw  406  such that rotation of the screw causes the carriage to move along the length of the screw. The screw  406  is rotated in a first direction to move the carriage toward one end  406   a  of the screw and is rotated in the opposite direction to move the carriage toward the opposite end  406   b  of the screw. The carriage  412  is connected to a bearing, roller or slider  415  that is received in a track  418  mounted on the housing  402  to guide and support the carriage  412  as it moves along screw  406 . A link  421  is connected to carriage  412  at pivot  417  and to actuator arm  420  at pivot  422 . The actuator arm  420  is connected to housing  402  at pivot  426 . Actuation of motor  410  rotates screw  406  to cause carriage  412  to move from end  406   b  toward end  406   a . Movement of carriage  412  pushes the linkage  421  which pushes arm  420  from the retracted position to the extended position. The carriage  412  is moved in the same direction as arm  420 . The opener of  FIG. 9  may be used with the sensor, controller, power source, return spring and limit switches/stepper motor as described above to control the motion of arm  420 . 
       FIG. 10  shows another embodiment of a push-type door opener in the extended or open position. The opener has a housing  502  mounted adjacent a door such that the front  502   a  of the housing  502  and actuator arm  520  face the door. The door is arranged such that it swings away from the front  502   a  of housing  502 . The housing  502  may be mounted to the top of a door jamb, a ceiling or other structure. The housing  502  supports a screw  506  comprising threads. The screw  506  is arranged at an angle relative to arm  520  when the arm is in the closed or retracted position. The screw  506  is rotated by a geared motor  510 . A carriage  512  is mounted on the screw  506  such that rotation of the screw causes the carriage to move along the length of the screw. The screw  506  is rotated in a first direction to move the carriage toward one end  506   a  of the screw and is rotated in the opposite direction to move the carriage toward the opposite end  506   b  of the screw. The carriage  512  is connected to a bearing, roller or slider  515  that is received in slot  521  formed in the housing  502  to guide and support the carriage  512  as it moves along screw  506 . 
     The carriage  512  is connected to a linkage  514  at a pivot  516 . The opposite end of the linkage  514  is pivotably connected to a point  520   c  (between ends  520   a  and  520   b ) of the actuating arm  520  at pivot  522  such that the arm  520  can rotate relative to the link  514 . The arm  520  is pivotably connected to the housing  502  at pin  526  that is located at a first end  520   a  of arm  520 . The arm  520  extends through a slot formed in the front  502   a  of housing  502  such that the arm  520  can be extended from the housing upon actuation of the motor  510 . The end  520   b  of arm  520  comprises a bearing surface  530  as previously described that contacts an exterior surface of the door to push the door and swing the door open. The device is a push-type in that the carriage moves in the same direction that the arm rotates and “pushes” the linkage to move arm to the open position. The opener of  FIG. 10  may be used with the sensor, controller, power source, return spring and limit switches/stepper motor as described above to control the motion of arm  520 . 
     While embodiments of the invention are disclosed herein, various changes and modifications can be made without departing from the spirit and scope of the invention as set forth in the claims. One of ordinary skill in the art will recognize that the invention has other applications in other environments. Many embodiments are possible. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described above.