Abstract:
An assist for use with a motorized door operating device to assist in the opening of a door during its movement from the closed position to an ajar position, and to assist in the closing of the door during its movement from the ajar position to the closed position. The device includes a connector mounted on one of the door and the wall and a motorized catch on the other of the door and wall for engaging and releasing the connector. During a door closing cycle, the assist remains inactive until the catch engages the connector, after which the motorized catch is moved in a first direction to move the door from the ajar position to the closed position. Upon the commencement of a door opening cycle, and upon completion of any unlatching cycle whereby any door latch retaining the door is released, the catch is moved in a second direction for moving the door from the closed position to the ajar position. Once the door is in the ajar position, the catch is disengaged from the connector and the door is allowed to move through the remainder of the door opening cycle without interference from the assist.

Description:
The present invention relates to door opening devices and, in particular, to a device to be used in conjunction with a door opener to overcome the resistance occurring when a door is moved between the closed position and the ajar position. 
     BACKGROUND OF THE INVENTION 
     In my prior U.S. Pat. No. 5,634,296 I disclosed a device which can be connected between a door and a wall for opening and closing the door against an opening in the wall. Although this device will reliably move a door between and open position and a closed position, the device does not satisfactorily solve two problems which may occur when the device is attached to a typical door. First, where the door has a latch assembly, including a rotatable doorknob, the door must also be fitted with some form of latch release. The most commonly known latch release is the type found in apartment buildings which permits the occupants of apartments to electronically release a latched door by releasing the latch plate in the wall. 
     Another problem not adequately solved by the door opener in my prior U.S. Pat. No. 5,634,296 is the resistance incurred in moving a door between an ajar position and a closed position. When a door is moved between an ajar position to a fully open position, a door opening device such as disclosed in my prior patent need only overcome the resistance provided by the hinges retaining the door to the wall, and the resistance of the air disturbed by the movement of the door. The closing of a door from an open position to an ajar position also requires relatively little force. A much greater force may be required, however, to move the door between an ajar position and a closed position. An outer door, for example, has seals to prevent the leakage of air into or out of the enclosed premises and the seals cause added resistance during only the portion of the swing of the door between the ajar position and the closed position. The closing of a door against a door latch will also cause greater resistance in this small portion of the swing of the door. 
     A door controlling device in accordance with my prior patent could be fitted with a motor and a linkage sufficiently powerful to overcome all the forces incurred to fully open or fully close a door, but such a device would encounter another problem. The door controller of my prior patent includes an obstruction sensing device for terminating the operation thereof when the door encounters an object such as a chair or a person&#39;s hand. When the door operator is fitted on a door which incurs a great deal of resistance in moving between the ajar and closed positions, the obstruction sensing device must not be so sensitive as to be triggered during this portion of an opening or closing cycle. It would, therefore, be desirable to provide a device which would be used in conjunction with a door opener such as disclosed in my prior U.S. Pat. No. 5,634,296 which would apply additional force at the end of a door closing cycle to move the door between the ajar position and the closed position, and provide additional force at the beginning of the door open cycle to move the door between the door closed position and an ajar position. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention is an assist to be used in conjunction with a motorized door operating device to assist in the opening of a door during its movement from the closed position to an ajar position, and to assist in the closing of the door during its movement from an ajar position to a closed position. The assist includes a connector mounted on one of the door and the wall and a moveable means mounted on the other of the door and wall for engaging and releasing the connector. During a door closing cycle, the assist remains inactive until the moveable means engages the connector, after which the moveable means moves in a first direction relative to the door or the wall to which it is attached. Movement of the moveable means in the first direction will move the door from the ajar position to a closed position. Upon the commencement of a door opening cycle, and upon completion of any unlatching cycle whereby any door latch retaining the door is released, the moveable means is moved in a second direction for moving the door from a closed position to an ajar position. Once the door is in the ajar position, the moveable means is disengaged from the connector and the door is allowed to move through the remainder of the door opening cycle without interference from the device. 
     In the preferred embodiment the assist includes a first detector for detecting when the moveable means has engaged with the connector during a closing cycle such that the moveable means will not commence its movement until the parts are in engagement. The assist further includes second and third detectors for detecting when the moveable means has reached the end of its travel in either the first direction or the second direction for terminating power to the motor upon completion of a cycle. 
     For a door which does not require the turning of a knob to release a latch, an opening cycle may be commenced simultaneously with the commencement of a door opening cycle of a door opener such as disclosed in my prior patent. A closing cycle is commenced when the first detector detects that the moveable means has engaged the connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be had after a reading of the following detailed description taken in conjunction with the following drawings wherein: 
     FIG. 1 is a fragmentary front view of a door having an assist assist in accordance with the present invention attached to a door which is in the closed position; 
     FIG. 2 is a fragmentary side view of a partially opened door in a wall fitted with the assist of FIG. 1; 
     FIG. 3 is a top elevational view of the assist shown in FIG. 1 with the door in an ajar position. 
     FIG. 4 is a side elevational view of the door and assist shown in FIG. 3; 
     FIG. 5 is a front elevational view of the assist on a door in the ajar position; 
     FIG. 6 is a side elevational view of the assist on a door in the closed position; 
     FIG. 7 is a fragmentary enlarged cross sectional view of the assist showing the mounting of the parts on the output shaft thereof; and 
     FIG. 8 is a block diagram of the circuit for the assist shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a door  10  is pivotal about the about the axis of pins  12  of hinges to open and close the door against a frame which defines an opening  13  in a wall  14 . A door operating assist  16  is attached to the upper end of the door  10  and to the wall  14  and is operated by a start button  18 , which may be an infrared transmitter, which sends a signal to a receiver  19  connected to the assist  16 . The door is retained in a closed position by a latch  20  which can be released by rotating a door knob  22  or by an electrically operated latch release  24 . 
     When the door  10  is closed against the wall  14  and the start button  18  is actuated, the latch release  24  is actuated thereby releasing the latch  20  after which the door operating assist  16  will move through a door opening cycle and cause it to swing away from the wall  14 . When the door is open and the start button  18  is again actuated, the door operating assist  16  will move through a closing cycle and push the door into the opening  13  until the latch  20  is engaged. 
     Where the wall  14  is an outside wall of a structure and the door opening  13  includes seals to seal the interior of the structure against adverse elements, the movement of the door from the closed position as shown in FIG. 6 to the ajar position as shown in FIG. 4 may require a substantially greater force than that required to move the door from the ajar position to the fully open position. Conversely, during a closing cycle the movement of the door from an open position to an ajar position may require only a small fraction of the force required to move the door from an ajar to a fully closed position. The force required to overcome the resistance as the door is moved between the ajar position and the closed position may be overcome by providing a stronger motor and linkage in the door operating assist  16 , or it may be overcome by providing an assist  25  in accordance with the present invention. 
     As shown in FIGS. 1-6, the assist  25  is mounted adjacent to the door opening assist  16  and includes a bracket  26  mounted on the wall  14  and a power operated engagement unit  28  mounted on the door. The bracket  26  has a portion  30  for attachment to a wall and a contact plate  32  extending perpendicular thereto, having an outer end  34  and a central opening  36 . 
     The engagement unit  28  includes a U-shaped mounting plate  37  having spaced apart parallel end portions  38 ,  39  and a transverse center portion  40 . The assist  25  is depicted as being mounted with end portion  39  screwed to the door  10 , however, it may be attached to a door opening on the opposite side by mounting end portion  38  to the door  10  instead of end portion  39 . Mounted between end portions  38 ,  39  is a reversible DC motor  41  and gear assembly  42  having an output shaft  44  which extended through an opening, not shown, in the center portion  40 . 
     Referring to FIG. 7, an annular cam retainer  46  is fitted around the shaft  44  the central opening of which is a little larger than the outer diameter of the shaft  44  such that the cam retainer  46  is freely rotatable about the shaft  44 . The cam retainer  46  has a cylindrical mounting portion  48  and snuggly fitted around the circumference of the mounting portion  48  are first and second cam members  50 ,  52 . The cam members  50 ,  52  have annular bodies with protrusions  54 ,  56  thereon respectively which interact with limit switches as further described below. Extending radially from the body of the annular cam retainer  46  is a detector pin  58  the distal end of which is long enough to contact the outer end  34  of the contact plate  32  for detecting the engagement of the unit  28  with the plate  32  as is also further described below. 
     Axially outward of the cam retainer  46  on the output shaft  44  is a cam  60  which is locked to the shaft  44  for rotation therewith. The cam  60  has a flat  62  thereon which will interact with a limit switch  64  on the center portion  40  of mounting plate  37  when the cam  60  is in the standby position as is shown in FIG.  2 . Extending from the outer circumference of the cam  60  are a first drive bar  70  and a second drive bar  72  which are oriented at about 120 degrees apart from one another, are equally angularly spaced from flat  62  as shown and define a plane perpendicular to one of the door or the wall. As described below, drive bar  70  will engage bracket  26  to urge the door  10  from the ajar position to the closed position and drive bar  72  will urge the door  10  from the closed position to the ajar position. When the assist  25  is mounted to a door opening from the other side, and mounting portion  39  is screwed to the door  10 , the function of drive bars  70  and  72  will be reversed. 
     As best shown in FIGS. 3,  4 , and  5 , extending perpendicular to the surface of the central portion  40  of the mounting plate  37  are a pair of limit pins  80 ,  82  which extend axially parallel to the output shaft  44  sufficiently far to provide a limit to clockwise and counterclockwise rotation of the detector pin  58 . Positioned on the center portion  40  of the mounting plate  37 , on opposite sides of the output shaft  44  are second and third limit switches  84 ,  86  respectively which are adapted to be engaged by the protrusions  54 ,  56  of cam members  50 ,  52  respectively. 
     Referring to FIGS. 2,  3 , and  4 , when the door  10  is moved away from the wall  14  and the engagement unit  28  is disengaged from the bracket  26  as shown in FIG. 2, a spring  88  will urge the cam retainer  46  to rotate clockwise until the detector pin  58  attached thereto rests on the second limit pin  82 . When the pin  58  contacts the limit pin  82 , the cam retainer  46  will have rotated until the second protrusion  56  on cam  52  has engaged the third limit switch  86 . As can be seen, the detector pin  58  is sufficiently long enough for the distal end thereof to contact the outer surface  34  of the contact plate  32  when the door is subsequently moved back into the ajar position shown in FIG. 4, thereby causing counter clockwise rotation of the cam retainer  46  and the cam members  50 ,  52  and moving protrusion  56  out of contact with the third limit switch  86 . 
     When the door  10  is moved away from the wall  14  as shown in FIG. 2, cam  60  is in the stand by position, and the detector pin  58  is resting on the second limit pin  82 . The drive bars  70 ,  72  have lengths which are equal to each other and are short enough to permit the distal end of the bar  70  to move under the outer end  34  of the contact plate  32  as the door is subsequently moved from the open position as shown in FIG. 2 to the ajar position as shown in FIG.  4 . The drive bars  70 ,  72  are also long enough for the distal end of bar  70  to extend through the opening  36  in the contact plate  32  and contact the inner surface of the outer end  34  when cam  60  is rotated counterclockwise to move the door  10  to the closed position shown in FIG.  6 . 
     Referring to FIG. 8, the assist  25  further includes a first start switch  89  for initiating a cycle for moving the door from a closed position to an ajar position. The start switch  89  may be actuated simultaneously with the actuation of a door opening cycle for the door operating assist  16 , or may be sequenced to commence after completion of a release cycle from a latch release  24 . Where the assist  25  is to be initiated simultaneously with the door operating assist  16 , the start button  18  which commences an opening cycle for the door operator  16  may also serve as the first start switch  89 . On the other hand, where a latch release  24  is also employed, the first start switch  89  may be actuated electronically after the latch release  24  is activated. 
     The assist  25  further includes a logic  90 , which may be in the form of a microprocessor that is responsive to the start switch  89 , the first limit switch  64 , the second limit switch  84 , and the third limit switch  86 , and which directs power to the motor  41  to rotate the output shaft  44  in either a clockwise or a counter clockwise direction. 
     To move a door from the closed position as shown in FIG. 6 to an ajar position as shown in FIG. 4, the first switch  89  is actuated either by depressing a button  18  or by the actuation of a latch release  24 . Upon detecting the actuation of the start switch  89 , the logic  90  directs power to the motor  41  to rotate the drive shaft  44  in a clockwise direction. The cam  60  rotates with the output shaft  44 , until the second drive bar  72  contacts the outer end  34  of the bracket  26 . Continued clockwise rotation of the shaft  44  will cause the second drive bar  72  to push against the outer end  34  of the contact plate  32  and thereby push the door  10  out of the opening  13  and into the ajar position. 
     As the door moves toward the ajar position, the spring  88  will rotate cam retainer  46  clockwise thereby maintaining the distal end of pin  58  against contact plate  32 . The second cam member  52  will rotate with the cam retainer  46  causing protrusion  56  to engage the third limit switch  86 . When the logic  90  detects that the third limit switch  86  has been actuated, it will reverse the power to the motor  41 , thereby causing output shaft  44  to commence rotating in a counter clockwise direction. The cam  60  will rotate counter clockwise with the shaft  44  until the first limit switch  64  engages the flat  62 , and on the actuation of switch  64  the logic  90  will terminate power to the motor  41  thereby returning the cam  60  to the standby position as shown in FIG.  2 . The assist will then remain inactive until it is again actuated by the door being moved from an open position into an ajar position. 
     When the door is closed by the door operator  16 , the engagement unit  28  will again engage the bracket  26  and the distal end of the detector pin  58  will encounter the outer end  34  of the contact plate  32  just before the door reaches the ajar position. As the door continues to close, movement of the door into the ajar position will cause the detector pin  58  and cam holder  46  to be rotated counterclockwise about the shaft  44  and cause the protrusion  56  of the second cam member  52  to move away from the third limit switch  86  thereby deactivating the switch  86 . When the logic  90  detects that the third limit switch  86  has become deactivated, it will apply DC power to the motor  41  for rotation of the shaft  44  and the cam  60  and drive bars  70 ,  72  in a counter clockwise direction. As the drive bar  70  rotates in a counter clockwise direction the distal end thereof will extend through the central opening  36  and engage the inner portion of the outer end  34  of the contact plate  32  and pull the distal end of the door  10  into opening  13  until the door is moved to the closed position shown in FIG.  6 . After the output shaft  44  and the cam  60  have rotated enough to move the door into the closed position, the first protrusion  54  of first cam member  50  will engage the second limit switch  84 , and in response thereto, the logic  90  will reverse the polarity of power to the motor  41  and thereby causing it to commence rotating in a clockwise direction. The motor  41 , the output shaft  44 , the cam  60 , and drive bars  70 ,  72  will rotate in the clockwise direction until the flat  62  is engaged by the first limit switch  64 , and in response to which the logic  90  will terminate power to the motor  41 . The assist shall then be again returned to the standby position and be ready for further actuation. 
     As can be seen, the pin  58  and the drive bars  70 ,  72  will not interfere with the movement of the door  10  when the assist is not in use. The door may be manually opened and closed and the engagement of the pin  58  with the outer end  34  of the bracket  26  will not inhibit the manual opening and closing of the door. 
     To operate properly, switch  84  must be actuated by protrusion  54  immediately after the door  10  is moved from the ajar position and into the closed position. Similarly, switch  86  must be actuated immediately after the door  10  is moved from the closed position into the ajar position. The timing of the actuations of these two switches are adjusted by rotating the cam members  50 ,  52  about the cam retainer  46 . 
     To modify the assist  25  for attachment to a door opening in the other side, the spring  88  is repositioned to urge the cam retainer to rotate counter clockwise rather than clockwise as shown. Also, the logic  90  is modified to switch the rolls of switches  84  and  86 . 
     While the present invention has been disclosed with respect to a single embodiment, it will be appreciated that many variations and modifications may be made without departing from the true spirit and scope of the invention. It is, therefore, the intent of the appendent claims to cover all variations and modifications that fall within the true spirit and scope of the invention.