Patent Abstract:
An apparatus for opening and closing a door remotely includes a remote radio control, electrically operated strike plate, and a door opening assembly attached to the door. A double acting piston is attached to a fixture on the floor. An actuator rod coupling assembly allows the door to move freely in a normal manner when the apparatus is deactivated. The coupling assembly has a detent which will release the piston rod in case of a sudden excessive force on the door that would otherwise damage the apparatus. The piston is a double acting piston that includes pressure switches to deactivate the pump when the pressure exceeds a threshold to prevent damage to the assembly. The mechanism can use potable water as the hydraulic fluid to eliminate contamination and fire hazards. The electrical system uses 12 volt DC operating voltages to eliminate electric shock.

Full Description:
FIELD OF THE INVENTION 
     The present invention is directed to a remote control operating assembly for opening and closing a door. More particularly, the invention is directed to an assembly for opening and closing a door where the assembly can be deactivated to allow manual operation of the door without interference from the operating assembly. 
     BACKGROUND OF THE INVENTION 
     A number of door opening mechanisms are known in the art for automatically opening and closing a door. These devices are particularly desirable for use by people having disabilities that can have difficulties in opening doors. 
     The automatic door opening devices typically include a bracket mechanism extending between a door and a door frame and include a suitable motor or hydraulic pressure source driving a double acting piston for generating the necessary force to open the door. The amount of force required to open a door can vary in relation to the location of the operating mechanism. Many door operating mechanisms are constructed so that the mechanism engages the door at a point close to the hinge of the door. This arrangement requires considerable force to open and close the door, thereby requiring a large power source. 
     Various devices have been proposed for remote operation of a door. These devices generally include a remote control unit that can be operated by the user to selectively open and close the door. Examples of these prior devices are disclosed in U.S. Pat. No. 5,375,374 to Rohroff and U.S. Pat. No. 5,634,296 to Hebda. These devices include a receiving unit and an electric motor for operating the mechanism. 
     Automatic door operating mechanisms generally require a clutch mechanism to disengage the operating mechanism so that the door can be operated manually. Many automatic door operating devices use a slip type clutch that allows the door to be opened and closed without turning the shaft of the electric motor. However, a disadvantage of the clutch-type devices is that they produce a significant drag or resistance on the door when the door is operated manually. The clutch mechanism allows the clutch to slip during the opening or closing cycle when the door strikes an obstruction. Although the movement of the door stops, the door operating mechanism continues throughout the opening and closing cycle. In this manner, the force against the obstruction continues until the end of the opening or closing cycle which can cause injury to a person or damage to the mechanism. 
     The manual operation of many hydraulic operated door mechanisms requires considerable force to transfer the hydraulic fluid from one side of the double acting piston to the other. 
     Although these devices have been effective for their intended purpose, there is a continuing need in the industry for an improved door operating mechanism. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an automatic door operating mechanism. More particularly, the invention is directed to a door operating mechanism for opening and closing a door from a remote location. 
     Accordingly, a primary object of the invention is to provide a remote controlled door operating assembly for opening and closing a door that overcomes the disadvantages of the prior door opening devices. 
     Another object of the invention is to provide a door operating assembly that can be easily installed by the home owner to an existing door using commonly available tools. 
     A further object of the invention is to provide an automatic door operating assembly that can be deactivated to allow manual operation of the door with minimal interference or resistance by the door operating assembly during the manual operation of the door. 
     A further object of the invention is to provide a door operating assembly having a release mechanism to disengage the door operating assembly when a threshold force is applied to the door. 
     Still another object of the invention is to provide a door operating assembly having a release mechanism to effectively disengage the operating assembly from the door and prevent an opening or closing force applied to the door when the door meets an obstruction. 
     Another object of the invention is to provide a door operating assembly that is able to operate on a low voltage DC current to reduce the risk of injury caused by an electric shock. 
     A further object of the invention is to provide a door operating assembly including a double action hydraulic cylinder for selectively opening and closing the door. 
     Still another object of the invention is to provide a door operating assembly using a hydraulic piston and cylinder that can operate using water as the operating fluid. 
     Another object of the invention is to provide a door operating assembly having a hydraulic piston drive assembly and a releasable coupling mechanism for selectively coupling the door to the piston rod for engaging and disengaging the piston with the door. 
     Another object of the invention is to provide an automatic door operating assembly having a release mechanism with a spring biased detent for selectively engaging a piston rod of a drive assembly. 
     A further object of the invention is to provide a remote controlled door operating assembly having a door opening mechanism and a strike plate attached to the door frame where the strike plate is actuated to allow the door to open by the door operating mechanism. 
     These and other objects of the invention are basically attained by providing an apparatus for opening and closing a door hinged to a door frame. The apparatus comprises a first bracket mounted on a support surface and being in a fixed position with respect to the door. A door actuator assembly has a first end pivotally coupled to the first bracket and a second end. The actuator assembly further has an actuator rod extending from the second end of the actuator assembly and is movable between an extended position and a retracted position. A second bracket is coupled to the door at a location spaced from the door frame. The actuator rod is slidably coupled to the second bracket. A coupling assembly is coupled to the second bracket for selectively capturing the actuator rod to open and close the door by actuating the actuator rod between the extended position and the retracted position. 
     The objects and advantages of the invention are further attained by providing an automatic door operating assembly for opening and closing a door hinged to a door frame. The assembly comprises a first bracket mounted on a support surface, and is in a fixed position with respect to the door. A door actuator has a piston and cylinder assembly. The cylinder has a first end pivotally coupled to the first bracket and a second end spaced from the first end. An actuator rod has a first end coupled to the piston and a second end spaced from the second end of the cylinder. A second bracket is coupled to the door. A coupling assembly is provided for coupling the actuator rod to the second bracket. The coupling assembly includes a body coupled to the second bracket. The body has a hole defining a passage extending therethrough. The second end of the actuator rod extends through the hole and is slidable therein. A detent is coupled to the body. The detent is movable between an extended position for engaging and capturing the actuator rod and a retracted position for releasing the actuator rod. The actuator rod is movable between a retracted position to open the door and an extended position to close the door. 
     The objects and advantages of the invention are also attained by providing a remote operated door operating assembly for opening and closing a door hinged to a door frame. The assembly comprises a first bracket mounted on a support surface in a fixed position with respect to the door. A door actuator has a fluid operated piston and cylinder assembly. The cylinder has a first end pivotally coupled to the first bracket and a second end spaced from the first end. An actuator rod has a first end coupled to the piston and a second end spaced from the second end of the cylinder. The actuator rod is movable between an extended door closing position and a retracted door opening position. A second bracket is fixed to the door. A coupling assembly is provided for coupling the second end of the actuator rod to the second bracket. The coupling assembly has a coupling member movable between a retracted position and an extended position for capturing the actuator rod. A door latching assembly for latching the door in a closed position is provided. The latching assembly has a movable strike plate coupled to the door frame and is movable from a latching position to an open position to allow the door to open. A remote control device is provided for operating the door actuator, coupling assembly and latching assembly from a remote location to selectively open and close the door. The door can be opened manually when the coupling member is in the retracted position without interference from the door actuator. 
     The objects, advantages and other salient features of the invention will become apparent from the following detailed description of the invention in connection with the annexed drawings which form a part of this original disclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following is a brief description of the drawing, in which: 
     FIG. 1 is a front view of a door and door frame including the door operating mechanism of the invention; 
     FIG. 2 is a top view of the door and door operating mechanism of the embodiment of FIG. 1 in the closed position; 
     FIG. 3 is a top view of the door and door operating mechanism in the open position; 
     FIG. 4 is an exploded view of the floor mounting bracket and hydraulic cylinder for operating the door operating mechanism; 
     FIG. 5 is a cross-sectional view of the hydraulic cylinder of the door operating mechanism; 
     FIG. 6 is a schematic view of the pump and valve system for operating the hydraulic cylinder of the door operating mechanism; 
     FIG. 7 is a side view of the coupling mechanism for coupling the door operating mechanism to the door; 
     FIG. 8 is an exploded perspective view of the coupling mechanism of FIG. 7; 
     FIG. 9 is an end view of the coupling mechanism of FIG. 7; 
     FIG. 10 is a partial cross-sectional side view of the coupling mechanism of FIG. 7 showing the detent in the coupling position; 
     FIG. 11 is a cross-sectional side view showing the detent in the disengaged position; 
     FIG. 11A is a cross-sectional side view of the microswitches in an alternative embodiment of the invention; 
     FIG. 12 is a perspective view of the strike plate release assembly in one embodiment of the invention; 
     FIG. 13 is a top view in partial cross-section showing the movable strike plate in the latching position; and 
     FIG. 14 is a front view of the strike plate assembly as seen with the door in the open position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to an automatic door operating assembly for selectively opening and closing a door. More particularly, the invention is directed to a remote controlled door operating assembly. 
     Referring to the drawings, door operating assembly  10  includes a door actuator assembly  12  and a coupling assembly  14  for connecting the door actuator assembly  12  to a door  16 . Door  16  is mounted to a door frame  18  by hinges  20  for pivoting between an open and closed position in a conventional door handle. A conventional door handle and latch assembly  22  is mounted on door  16  for latching door  16  in a closed position. 
     Referring to FIGS. 1-4, door actuating assembly  12  includes a hydraulic piston assembly  26  having an actuating rod  28 . Hydraulic piston assembly  26  has a first end  30  having a coupling arm  32 . As shown in FIG. 4, coupling arm  32  of hydraulic piston assembly  26  includes an aperture  34  for receiving a coupling pin  36 . Coupling arm  32  is connected to a bracket  38  for pivoting movement about a vertical axis. Bracket  38  includes a bottom plate  40  for mounting directly to the floor adjacent the door frame  18 . Bottom plate  40  includes a plurality of apertures  42  for receiving mounting screws  44 . A plate  46  extends upwardly from bottom plate  40  and includes two spaced apart legs  48  extending generally parallel to bottom plate  40 . Legs  48  include an aperture  50  for receiving coupling pin  36 . Coupling arm  32  of hydraulic piston assembly  26  is received between legs  48  and coupled thereto by coupling pin  36  for pivotal movement about a vertical axis. 
     Referring to FIG. 5, hydraulic piston assembly  26  includes a cylinder  52  and a reciprocating piston  54  within cylinder  52 . Cylinder  52  has open ends that are closed by end caps  56  and  58 . End cap  56  has an end wall  60  and a side wall  62  dimensioned to fit over the end of cylinder  52 . Coupling arm  32  includes a threaded end that extends through a central opening in end wall  60  of end cap  56 . A threaded nut  64  is threaded onto the threaded end of coupling arm  32  for attaching coupling arm  32  to end cap  56 . 
     End cap  58  includes an end wall  66  and a side wall  68  for coupling to the open end of cylinder  52  opposite end cap  56 . End wall  66  includes a central aperture  70  for receiving actuator rod  28 . 
     Piston  54  as shown in FIG. 5 has a radial face  72  with a groove for receiving a seal  74 , such as an O-ring. Piston  54  and seal  74  are dimensioned to contact the inner surface  76  of cylinder  52  to form a fluid seal. In the embodiment illustrated, actuator rod  28  extends completely through a central aperture in piston  54 . 
     Actuator rod  28  has a first end  78  and a second end  80 . Two spaced-apart transversely extending holes extend completely through actuator rod  28  and are spaced from first end  76  for receiving cotter keys  82 . Cotter keys  82  are positioned to couple actuator rod  28  to piston  54 . As shown in FIG. 5, first end  78  of actuator rod  28  extends from piston  54  a sufficient distance to serve as a stop member by contacting nut  64  and limiting movement of piston  54  toward end cap  56  along the longitudinal dimension of cylinder  52 . 
     Referring to FIG. 5, a circular support plate  84  is mounted in cylinder  52  adjacent end cap  58 . Support plate  84  has a central aperture  86  for receiving actuator rod  28 . Aperture  86  of support plate  84  is dimensioned for receiving a seal  92 . Typically, seal  92  is an O-ring dimensioned to seal against the outer surface of actuator rod  28  and the inner surface of aperture  86 . An end plate  94  is also mounted in cylinder  52  adjacent support plate  84  as shown in FIG.  5 . End plate  94  also has an opening  95  aligned with aperture  86  to allow actuating rod  28  and piston  54  to reciprocate within cylinder  52 . End plate  94  retains seal  92  in aperture  86 . 
     A sleeve  96  is coupled to actuator rod  28  adjacent piston  54  opposite first end  78 . Sleeve  96  can be coupled to actuator rod  28  by a friction fit or by a suitable fastener. Sleeve  96  has an outer diameter greater than opening  95  in end plate  94  so that sleeve  96  functions as a stop member to limit axial movement of piston  54  and actuator rod  28  within cylinder  52  when piston  54  moves toward end cap  58 . 
     In embodiments of the invention, cylinder  52  and end caps  56  and  58  are made of a plastic material such as PVC having sufficient strength to withstand the hydraulic pressures and stresses necessary to open and close a door. In the embodiments of the invention where end cap  58  is made of a plastic material or other soft material, a bearing  100  is attached to the outer face of end cap  58  to reduce wear on end cap  58  by the reciprocating motion of actuator rod  28 . Bearing  100  is generally made of metal or other wear resistant material. In further embodiments, cylinder  52  is made of metal, such as steel, having sufficient strength and wear resistance to operate efficiently. 
     Cylinder  52  includes fluid openings  102  adjacent each open end. A fluid coupling  104  extends through each opening  102  to transfer an operating fluid to cylinder  52  on opposite sides of piston  54 . Each coupling  104  includes an axial passage  106  and a threaded tip  108 . Fluid coupling  104  also includes a base  110  having a diameter greater than the diameter of openings  102  for retaining fluid coupling  104  in the respective opening  102 . In the embodiment illustrated, each fluid coupling  104  is made of rubber of other flexible material and is able to snap into the respective opening  102 . 
     Referring to FIG. 5, fluid coupling  104  are positioned in the side wall of cylinder  52  at opposite ends. The base  110  of each fluid coupling is positioned in the path of piston  54  so that first end  78  of actuator rod  28  and sleeve  96  have a length to limit the linear movement of piston  54  to prevent piston  54  from contacting the fluid coupling  104 . 
     As shown in FIG. 2, fluid couplings  104  are connected to flexible conduits  112  that are connected to a fluid control  114  for providing a fluid supply for controlling the operation of piston assembly  26 . FIG. 6 is a schematic diagram of the fluid control  114  which includes a first pump  116  with a check valve allowing flow only to cylinder  52  connected to a fluid sump  118  by a line  120 . Pump  116  supplies fluid through a line  122  to a line  124  which is coupled to one of the fluid couplings  104 . Line  124  is also connected to a normally open valve  126  for directing fluid through a line  128  back into sump  118 . A second pump  130  as above is connected to sump  118  by a line  132 . Pump  130  supplies fluid under pressure through a line  134  to the second fluid coupling  104  through a line  136 . Line  136  extends to a normally open valve  138  for directing fluid to line  128  for returning the fluid to sump  118 . In a preferred embodiment, the operating fluid is water to eliminate the risk of fire or leakage of toxic liquids. In further embodiments, the door operating assembly can use conventional hydraulic fluids or can be pneumatically operated. Preferably, the operating pumps are operated by low voltage motors, such as 12 volt motors, to reduce the risk of electric shock. 
     Fluid control  114  includes a control device  140  for actuating pumps  116  and  130  and selectively opening and closing valves  126  and  138 . In preferred embodiments of the invention, control device  140  is a remote control device that is operated by a hand-held remote control unit  24 . Remote control unit  24  shown in FIG. 2 includes suitable electronic circuitry as known in the art for operating fluid control  114 . In the embodiment illustrated in FIG. 1, remote control unit  24  is provided with two actuator buttons  142  for selectively opening and closing door  16  although the actual number of buttons can vary depending on the circuitry used. During use, remote control unit  24  is actuated to initiate an opening operation. 
     During the door opening operation cycle, pump  116  is actuated to pump fluid from sump  118  through line  122  into cylinder  52  to move piston  54  toward end cap  56  and retract actuator rod  28 . Fluid on the opposite side of piston  54  returns to sump  118  through normally open valve  138 . Control device  140  closes valve  126  to force the fluid into cylinder  52 , thereby retracting actuator rod  28  from the position shown in FIG. 2 to the retracted position shown in FIG.  3 . Retracting actuator rod  28  with actuating rod  28  coupled to door  16  through coupling assembly  14  causes door  16  to pivot about the hinges  20  and causes hydraulic piston assembly  26  to pivot about pin  36  on floor bracket  38  as shown in FIG.  3 . 
     As shown in FIG. 5, first end  30  of actuator rod  28  contacts nut  64  to limit the axial movement of piston  54  and prevents piston  54  from contacting the base  110  of fluid coupling  104 . In preferred embodiments, pump  116  includes a pressure sensor to sense an increase in fluid pressure in line  122  above a predetermined level. The pressure sensor is connected to control device  140  and provides an indication that piston  54  has reached the end of its stroke when the pressure increases to the predetermined level. When a threshold pressure is detected by the pressure sensor, control device  140  deactivates pump  116  to end the opening cycle. The pressure sensor in pump  116  also senses an increase in fluid pressure in line  122  if door  16  should hit an obstruction, thereby preventing movement of the door. The increase in pressure sensed causes control device  140  to deactivate pump  116  to prevent damage to pump  116  and the other components of the system as well as reducing the risk of injury to a person that may be in the way of the door. 
     Door  16  is closed by actuating remote control unit  24  which in turn activates control device  140 . Control device  140  closes valve  138  while actuating pump  130  to supply fluid under pressure through line  134  to cylinder  52 . The fluid then forces piston  54  toward end cap  58  to move actuator rod  28  to the extended position shown in FIG. 2, thereby closing door  16 . The closed door against the door stop causes the increased pressure stopping the pump. This occurs before the piston reaches its maximum travel position. The fluid in cylinder  52  is then forced through line  124 , normally open valve  126  and line  128  where the fluid is returned to sump  118 . 
     In preferred embodiments of the invention, coupling assembly  14  is able to selectively engage and disengage actuator rod  28  so that door  16  can be opened and closed manually without moving actuator rod  28  and piston  54 . Coupling assembly  14  is normally disengaged from actuator rod  28  so that door  16  can be open and closed manually without interference by door actuating assembly  12 . Referring to FIGS. 7-11, coupling assembly  14  includes a mounting bracket  150  attached to door  16  by screws or other suitable fasteners. Bracket  150  includes a base  152  for mounting to door  16  and an outwardly extending arm  154 . Arm  154  has an aperture  156  extending therethrough for receiving a pivot pin  157 . A body  158  includes a U-shaped member  160  on each side of body  158  for pivotally coupling body  158  to bracket  150 . U-shaped members  160  are provided on each side of body  158  to allow body  158  to be coupled to bracket  150  for accommodating doors that are hinged to the right or left side of a door frame. 
     Body  158  in the embodiment shown has a generally rectangular shape with a longitudinal passage  162  extending completely through body  158 . Longitudinal passage  162  is dimensioned to receive actuator rod  28  and to allow actuator rod  28  to slide freely within body  158 . Body  158  also includes a transverse passage  164  extending from a top surface  166  and intersects with longitudinal passage  162 . A coupling member  168 , shown as a pin, is mounted for movement in transverse passage  164 . 
     In preferred embodiments, actuator rod  28  has a recess  170  formed in the outer surface spaced from a second end  172  as shown in FIGS. 7 and 8. Recess  170  in rod  28  is formed with an inclined leading edge  174  and an inclined trailing edge  176 . Recess  170  is dimensioned to receive coupling member  168  for affixing actuator rod  28  to coupling assembly  14  and prevent actuator rod  28  from sliding through body  158 . As discussed hereinafter in greater detail, coupling member  168  is preferably spring biased toward longitudinal passage  162  when in the actuating position to be received in recess  170  of actuator rod  28 . 
     During the operation of door actuating assembly  12 , coupling member  168  is moved to the downward position shown in FIGS. 7 and 10 to capture actuator rod  28 . Capturing actuator rod  28  by coupling member  168  enables door  16  to be open and closed by operation of hydraulic piston assembly  26  as discussed above. In the event door  16  contacts an obstruction or other object in its normal movement that prevents door  16  from moving, pressure increases, is sensed and the pump stops and rod  28  is released. Inclined edges  174  and  176  of recess  170  cause coupling member  168  to slide upwardly within passage  164  and allow actuator rod  28  to slide within body  158  when a sudden force is applied that is larger than the force applied during normal operation. In this manner, actuator rod  28  continues moving the movement of piston  54  but does not apply excessive force to door  16 , thereby preventing damage to the various components of the assembly and preventing injury to a person that may have fallen against the door. The angle of edges  174  and  176  with respect to the axial dimension of actuator rod  28  and the spring pressure against coupling member  168  determines the force necessary to release actuator rod  28  from body  158 . 
     Referring to FIG. 8, coupling member  168  extends through a block  178  having upper and lower camming plates  180  and  182 , respectively. In the embodiment illustrated, coupling member  168  includes a threaded upper end for receiving a nut  184  for attaching coupling member  168  to block  178  and cam plates  180  and  182 . As shown in FIG. 7, the lower cam plate  182  serves as a stop to limit the downward movement of coupling member  168  within transverse passage  164 . 
     Coupling assembly  14  also includes a housing  186  that is hinged to body  158  by a hinge  188  and hinge pin  190 . Housing  186  includes a side wall  192  connected to hinge  188  and an end wall  194  extending perpendicular to side wall  192 . End wall  194  is provided with a hook  196  at a top end of end wall  194  opposite side wall  192 . A spring  198  extends from hook  196  to U-shaped member  160 . Housing  186  is able to pivot about hinge  188  and is biased by spring  198  in a downward direction toward body  158 . It will be appreciated that portions of side wall  192  and top wall  193  are cut away to show the actuating assembly  200 . 
     Housing  194  supports an actuating assembly  200  for operating coupling member  168 . Referring to FIGS. 8 and 9, actuating assembly  200  includes an eccentrically mounted cam  202  mounted on a shaft  204 . Shaft  204  is coupled to a motor  206  for rotating cam  202 . Preferably, motor  206  is a gear motor. Cam  202  is dimensioned to fit between camming plates  180  and  182 . Cam  202  has a substantially cylindrical shape and is eccentrically mounted whereby rotation of shaft  204  produces a reciprocating motion to cam plates  180  and  182  and coupling member  168 . As shown in FIG. 10, cam  202  has an outer end that is received between cam plates  180  and  182  and an inner end spaced from the edges of the cam plates. 
     A lower guide plate  208  extends outwardly from end wall  194  of housing  186  adjacent cam  202 . An upper guide plate  210  extends outwardly from end wall  194  adjacent an upper end and extends generally parallel to lower guide plate  208 . Lower guide plate  208  includes an aperture  212  and upper guide plate  210  includes an aperture  214  for receiving a reciprocating guide pin  216 . Guide pin  216  slides through apertures  212  and  214  and includes a lower end  218  for contacting the inner end of cam  202 . A stop member  220  is attached to guide pin  216  between upper guide plate  210  and lower guide plate  208 . A coil spring  222  surrounds guide pin  216  and extends between upper guide plate  210  and an upper face  224  of stop member  220  to bias guide pin  216  in a downward direction toward cam  202 . Preferably, spring  222  maintains lower end of guide pin  216  in constant contact with cam  202 . Guide pin  216  is mounted for reciprocating movement through the respective aperture in upper guide plate  210  and lower guide plate  208 , whereby rotation of cam  202  produces a reciprocating motion to guide pin  216 . 
     As shown in FIG. 9, an upper microswitch  226  is mounted on end wall  194  toward upper guide plate  210 . Upper microswitch  226  is connected to motor  206  by wires  228  for controlling the operation of motor  206 . Microswitch  226  includes an actuating arm  230  positioned for contacting stop member  220  when guide pin  216  is in the uppermost position. A lower microswitch  232  is mounted on end wall  194  adjacent lower guide plate  208 . Lower microswitch  232  is also connected to motor  206  by wires  234  for controlling motor  206 . An actuating arm  236  extends outwardly from microswitch  232  for contacting stop member  220  when guide pin  216  is in the lowermost position shown in FIG.  9 . Motor  206  is connected by wires  238  to control device  140  for actuating motor  206  during the opening and closing operation of door  16 . In an alternative embodiment shown in FIG. 11A, microswitches  226 ′ and  236 ′ are positioned to engage cam  202 ′. In this embodiment, cam  202  actuates the microswitches to start and stop motor  206 ′ at the desired positions. 
     In operation, control device  140  operates motor  206  to control the capturing and disengagement of coupling assembly  14  to actuator rod  28 . Control device  140  actuates motor  206  to rotate cam  202  about shaft  204 . Rotation of cam  202  raises and lowers coupling member  168  into and out of engagement with actuator rod  28 . Coupling member  168  is moved into the capturing position by rotating cam  202  whereby cam  202  pushes lower cam plate  182  downward to the position shown in FIGS. 9 and 10. When cam  202  reaches its lowermost position shown in FIG. 9, guide pin  116  is biased downwardly causing stop member  220  to contact arm  236  of lower microswitch  232 . At this point, lower microswitch  232  stops the rotation of motor  206  to retain coupling member  168  in the capturing position. Coupling member  168  is disengaged by operating motor  206  causing cam  202  to rotate to the uppermost position, thereby retracting coupling member  168  within transverse passage  164 . The rotation of cam  202  moves guide pin  216  in an upward direction against the spring  222  until stop member  220  contacts arm  230  of upper microswitch  226 . Upper microswitch  226  then stops the rotation of motor  206  until motor  206  is again actuated by control device  140 . 
     As shown in FIGS. 9 and 10, housing  186  is spring biased by spring  198  in a downward direction toward body  158 . Spring  198  maintains coupling member  168  in contact with actuator rod  28 . In the event the door is heavily impacted with a force greater than that provided by the cylinder, inclined edges  174  and  176  of recess  170  in actuator rod  28  push coupling member  168  in an upward direction causing housing  186  to which motor  206  is mounted pivots about hinge  188  as shown by phantom lines in FIG.  9 . If the shoulders of the recess in rod  28  were square, the excessive force would be transmitted to the mounting hardware  38  and  14  possibly causing failure. The pivoting on hinge  188  also allows pin  168  to come down on rod  28  other than the recess location and still allow the motor to turn the cam, thus preventing stalling of the motor which would cause the motor to burn out. This action occurs if the door is partially open when the operating assembly is put in motion. In such case, the tip of pin  168  slides along rod  28  until it enters the recess. If the door is obstructed in normal operation, the pressure built up will stop the motion of the piston in the same manner as when the door reaches its open and closed positions. 
     In preferred embodiments of the invention, a retractable strike plate assembly  250  is mounted on door frame  18  cooperating with door latch  22  for retaining door  16  in the closed position. Referring to FIGS. 12-14, strike plate assembly  250  includes a housing  252  and a bottom wall  254 . 
     Housing  252  includes a front wall  256  having an angled section  258  extending as a mounting leg  260  for coupling housing  252  to door frame  18 . It will be appreciated that portions of housing  252  are cut away for purposes of illustrating the various components of strike plate assembly  250 . Angled section  258  and mounting leg  260  mounted either above or below the latch allow door latch  22  to pass during opening and closing of door  16 . A movable strike plate  264  is hinged to an end wall  266  of housing  252  by a hinge  280 . Movable strike plate  264  includes a first leg  268  connected to an angled leg  270  having an end  274  which blocks door latch  22  to retain the door in the closed position shown in FIG. 13. A spring  276  is coupled to movable strike plate  264  and a rear wall  278  of housing  252  to bias movable strike plate  264  away from front wall  256  about a hinge  280 . 
     A motor  282  is mounted on bottom wall  254  and includes an eccentric cam  284  for moving movable strike plate  264  from a latching position to an unlatched position shown in phantom lines in FIGS. 13 and 14. Motor  282  is connected to a suitable power source and operated by control device  140  for selectively rotating cam  284  during operation of the assembly. During the door opening operation, motor  282  is operated to rotate cam  284  to the position shown in phantom lines in FIG.  13 . In this position, spring  276  pivots movable strike plate  264  about hinge  280  to the position shown in phantom lines in FIG.  13 . The retracted position of movable strike plate  264  releases latch  22  whereby hydraulic piston assembly  26  can open and close door  16 . 
     A microswitch  286  is positioned on bottom wall  254  to contact cam  284  at the point when movable strike plate  264  is in the unlatched position. Microswitch  286  is electrically connected to motor  282  to stop the rotation of motor  282  and cam  284  when movable strike plate  264  is in the retracted position. During the latching and door closing operation, control device  140  actuates motor  282  to rotate cam  284  to move movable strike plate  264  to the latching position of FIG. 13. A second microswitch  288  is provided on bottom wall  254  to engage cam  284  when cam  284  reaches the latching position to stop the rotation of motor  282 . 
     In preferred embodiments, strike plate assembly  250  is controlled remotely by control device  140  and remote control unit  24 . Strike plate assembly  250  is synchronized with hydraulic cylinder assembly  26  to retract strike plate  264  when hydraulic cylinder  26  is activated. The operator actuates remote control unit  24  to begin the door opening cycle. At this point, control unit  140  actuates motor  282  to rotate cam  284  and move movable strike plate  264  to the unlatching position. Simultaneously, control unit  184  actuates motor  206  of coupling assembly  14  to move coupling member  168  into the capturing position to capture actuator rod  28 . Hydraulic piston assembly  26  is then operated to open door  16  in the manner previously described. The operation is reversed to close door  16  and return strike plate  264  to the latching position and disengage coupling assembly  14  from actuator rod  28 . Door  16  can then be opened and closed manually by operating door latch  22  in a conventional manner to retract into door  16  free of strike plate  264 . 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Technology Classification (CPC): 4