Patent Application
20110094160
The purpose of a door operator is to open and close a door. Automatic door operators are used on public buildings and residences to allow for access by the physically disabled or where manual operation of the door may be inconvenient to users. In public facilities, it is a required American National Standard for doors that provide ingress and egress to have the ability to open automatically in order to allow handicapped people passage through the doorway.
A variety of electro-mechanical automatic door operators are known. A typical door operator includes an electric motor and a linkage assembly for operatively coupling the drive shaft of the motor to a door so that the door will be opened and closed when the drive shaft rotates. Activation of the door operator is initiated by means of an electric signal generated in a variety of ways such as, for example, a pressure switch, an ultrasonic or photoelectric presence sensor, motion sensors, radio transmitters, wall switches, and the like. The door may then be closed under power or with a door closer. A conventional door closer uses an internal spring mechanism which is compressed during the opening of the door for storing sufficient energy so that the door can be returned to a closed position without the input of additional electrical energy. In the some door operators, the automatic, powered opening system is still engaged once the closing sequence starts, and consequently the spring force of the door closer must overcome the resistance caused by counter-rotating the gear train coupled to the motor. Since this spring force must be large, an individual manually opening the door must exert substantial force to overcome the spring force and the resistance forces generated by the opening system. Moreover, driving the components of the powered opening system during manual opening and closing of the door causes the gear train to become worn more quickly over time.
Some door operator systems are provided with clutch mechanisms between the motor and the linkage assembly that enable the door to be moved freely under manual power. Door operators with clutch mechanisms may provide some level of safety when objects are in the door's pathway of movement. Various clutch mechanisms decouple powered opening systems during the closing cycle, which is particularly necessary in the event of an interruption of power supply or when an obstacle is encountered. Some require a sensor mounted in the motor housing or drive shaft to sense stoppage of the door by an obstacle and to disengage the clutch or stop the motor so as to prevent damage to the device or obstacle. This solution still presents problems. For example, a door operator utilizing a slip clutch or the like will create some drag or resistance when the door is manually opened or closed. Moreover, conventional clutch mechanisms that do not create resistance suffer from a limited range of motion.
Other known automatic door operator systems enable a user to open the door under automatic power or under manual power, and the systems use a predetermined, elapsed time in between opening and closing sequences. Under automatic power, a motor is operated by a controller and opens at a particular speed and direction. The motor may then stall or rest for the fixed, predetermined period. At the expiration of such time period, the controller then signals the motor to reverse direction and close the door under power. Under manual operation, the door is opened by the user. Once the user releases the door, which may be before the door has reached the fully open position, the controller may direct the motor to continue to open the door until reaching the fully open position, despite that the user may have already moved through the doorway. This operation may not be desirable in cases where the door is an outside door and the weather conditions cause considerable heat loss in the winter or heat gain in the summer. Moreover, security at building entrances may be a concern. Automatic door operator systems that delay return of a manually opened door to the closed position beyond the time needed for a person to move through the doorway create a heightened security risk, as there may be an extended opportunity for entry by an unauthorized person.
In accordance with one embodiment of a door operator, a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor and an operator arm assembly. The motor includes a drive shaft rotatable in a first direction adapted to open the door and in a second direction adapted to close the door. The operator arm assembly includes an output shaft operatively coupled to the drive shaft, a rotatable operator arm, and a clutch assembly. The rotatable operator arm defines an opening through which the output shaft passes and is adapted to be operatively connected to the door. The operator arm is adapted to have a closed position coincident with the closed position of the door and a fully open position coincident with the fully open position of the door. The clutch assembly is mounted to the output shaft and is conditionally operatively engageable with the operator arm. When a force is manually applied to move the operator arm towards the fully open position, the output shaft and operator arm are not operatively engaged, and when no manual force is applied the output shaft and the operator arm are operatively engaged.
The door operator may further include a door position sensor and a controller. The door position sensor may be for sensing the position of the operator arm. The controller may be in communication with the motor and the door position sensor. When the operator arm is manually moved towards the fully open position from the closed position, the operator arm operatively disengages from the clutch assembly, the sensor indicates to the controller that the operator arm position is not closed, the controller signals to the motor to rotate the drive shaft in the direction adapted to close the door, and the motor rotates the drive shaft in the direction adapted to close the door. The controller may further receive a signal for the door operator to move the operator arm towards the fully open position automatically and the motor may power the operator arm to reach a fully open position. The door position sensor may then indicate to the controller that the operator arm is in the fully opened position and the controller, either immediately or after a delay, may send a signal to the motor to reverse rotation of the drive shaft so as to cause the operator arm to move to the closed position. The door position sensor may then indicate to the controller when the operator arm is in the closed position, and the controller may send a signal to the motor to cease rotation of the drive shaft.
In accordance with another embodiment of a door operator, another door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor including a drive shaft rotatable in a first direction adapted to open the door and in a second direction adapted to close the door. An operator assembly includes an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes and adapted to be operatively connected to the door, and means for conditionally operatively engaging the output shaft with the operator arm. The operator arm is adapted to have a closed position coincident with the closed position of the door and a fully open position coincident with the fully open position of the door. When a force is manually applied to move the operator arm towards the fully open position, the output shaft and operator arm are not operatively engaged, and when no manual force is applied the output shaft and the operator arm are operatively engaged. Means for sensing the position of the operator arm and a controller in communication with the motor and the sensing means are provided.
In accordance with another embodiment of a door operator, another door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor including a drive shaft rotatable in a first direction adapted to open the door and in a second direction adapted to close the door, a operator arm assembly, an electro-magnetic door position sensor, a first magnet, and a controller. The operator arm assembly includes an output shaft operatively coupled to the drive shaft and a rotatable operator arm. The rotatable operator arm defines an opening through which the output shaft passes and is adapted to be operatively connected to the door. The operator arm is adapted to have a closed position coincident with the closed position of the door and a fully open position coincident with the fully open position of the door. The electro-magnetic door position sensor is for sensing the position of the operator arm, and the first magnet rotates about the axis of the output shaft as the output shaft turns, demarcating the closed position of the operator arm. The controller is in communication with the motor and the door position sensor. The door operator may further include a second magnet that rotates about the axis of the output shaft as the output shaft turns and is angularly spaced from the first magnet relative to the axis of the output shaft, as the second magnet demarcates the fully open position of the operator arm.
In accordance with another embodiment of a door operator, another door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor including a drive shaft rotatable in a first direction adapted to open the door and in a second direction adapted to close the door, an operator arm assembly, a support member, and a level. The operator arm assembly includes an output shaft operatively coupled to the drive shaft and a rotatable operator arm. The operator arm defines an opening through which the output shaft passes and is adapted to be operatively connected to the door. The operator arm is adapted to have a closed position coincident with the closed position of the door and a fully open position coincident with the fully open position of the door. The support member is for directly or indirectly supporting the motor and is adapted to be mounted to a door frame or structure proximate to the door frame. The level is mounted to the support member.
In accordance with an embodiment of a door assembly, a door assembly is provided and includes a door operator and a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position. The door operator includes a motor including a drive shaft rotatable in a first direction to open the door and in a second direction to close the door, an operator arm assembly, a door position sensor, and a controller. The operator arm assembly includes an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes, with the operator arm operatively connected to the door, and a clutch assembly. The clutch assembly is mounted to the output shaft and is conditionally operatively engageable with the operator arm. The clutch assembly includes at least one friction disc on each side of the operator arm and parts adjacent to the friction discs, and a spring for biasing the friction discs and the operator arm towards each other for transfer of rotation of the output shaft to the operator arm through static friction. The operator arm may be an adjacent part to at least one friction disc. The output shaft passes through the friction discs, adjacent parts, the operator arm, and the spring. The door position sensor is for sensing the position of the operator arm. The controller is in communication with the motor and the sensor. When the door is manually pushed open from the closed position, parts adjacent to the friction discs slide against the friction discs, the door position sensor indicates to the controller that the door is not closed, the controller signals to the motor to rotate the drive shaft in the direction that closes the door, and the motor rotates the drive shaft in such direction.
In accordance with another embodiment of a door operator, a method of using a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor including a drive shaft, an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes and adapted to be operatively connected to the door, a clutch assembly mounted to the output shaft and including at least one friction disc on each side of the operator arm and parts adjacent to the friction discs, a sensor for sensing the position of the operator arm, and a controller in communication with the motor and the sensor. The operator arm may be an adjacent part to at least one friction disc. The method includes manually pushing the door from a closed position towards the fully open position. The force of static friction between parts adjacent to the friction discs and the friction discs is overcome to initiate movement of the door, operatively disengaging the operator arm from the output shaft.
In accordance with another embodiment of a door operator, a method of making a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and an open position is provided. The method includes providing a motor including a drive shaft. An operator arm assembly is provided including an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes and adapted to be operatively connected to the door, and a clutch assembly mounted to the output shaft and conditionally operatively engageable with the operator arm. The operator arm is adapted to have a closed position coincident with the closed position of the door and a fully open position coincident with the fully open position of the door. When a force is manually applied to move the operator arm towards the fully open position, the output shaft and operator arm are not operatively engaged, and when no manual force is applied the output shaft and the operator arm are operatively engaged. A door position sensor is provided for sensing the position of the operator arm, and a controller in communication with the motor and the sensor is provided. The motor, operator arm assembly, and the controller are assembled.
In accordance with another embodiment of a door operator, a method of installing a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and an open position is provided. The door operator includes a support member, a motor mounted directly or indirectly to the support member and including a drive shaft, an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes and adapted to be operatively connected to the door, a clutch assembly mounted to the output shaft and including at least one friction disc on each side of the operator arm and parts adjacent to the friction discs, through all of which the output shaft passes, a spring to bias the friction discs and the operator arm together, a retaining nut to apply adjustable force to the spring, a sensor for sensing the position of the operator arm and door, and a controller mounted to the support member and in communication with the motor and the sensor. The operator arm may be an adjacent part to at least one friction disc. The method includes mounting the support member to a door frame or building structure proximate to the door frame. The operator arm is operatively connected to the door. The retaining nut is tightened to a torque that applies pressure to the friction discs and the operator arm sufficient to maintain operative engagement of the friction discs and adjacent parts when the door is powered by the motor. The applied torque allows static friction between the friction discs and at least two adjacent parts to be overcome when the operator arm is moved towards the open position manually, operatively disengaging the friction discs and at least two adjacent parts.
In accordance with another embodiment of a door operator, another method of installing a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and an open position is provided. The door operator includes a support member, a motor mounted directly or indirectly to the support member and including a drive shaft, an output shaft operatively coupled to the drive shaft, a rotatable operator arm defining an opening through which the output shaft passes and adapted to be operatively connected to the door, an electro-magnetic door position sensor for sensing the position of the operator arm, and a controller mounted to the support member and in communication with the motor and the sensor. The method includes mounting the support member to a door frame or building structure proximate to the door frame. The operator arm is operatively connected to the door, and a first magnet is disposed on a member that rotates around the axis of the output shaft. When the door is in the closed position the first magnet actuates the sensor. The method may further include disposing a second magnet on the member that rotates around the axis of the output shaft. The second magnet may be angularly spaced from the first magnet relative to the central axis of the output shaft, and when the door is in the fully open position the second magnet actuates the sensor.
In accordance with another embodiment of a door operator, another method of installing a door operator for selectively operating a door positioned within a door frame and hinged along one edge to the door frame for movement between a closed position and a fully open position is provided. The door operator includes a motor and a support member for directly or indirectly supporting a motor. An integral level is mounted to the support member. The method includes placing the support member of the door operator in contact with a door frame or building structure proximate to the door frame for mounting to the door frame or building structure proximate to the door frame. The alignment of the support member is adjusted such that the integral level indicates that the integral level is level, for example, horizontal or vertical. The support member is mounted to the door frame or building structure proximate to the door frame.
For a more complete understanding of embodiments of a door operator and associated methods, reference should now be had to the embodiments shown in the accompanying drawings and described below. In the drawings:
Certain terminology is used herein for convenience only and is not to be taken as a limitation on the embodiments described. For example, words such as “top”, “bottom”, “upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,” and “downward” merely describe the configuration shown in the figures. Indeed, the referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise.
As used herein, the term “open position” for a door means a door position other than a fully closed position, including any position between the fully closed position and a fully open position as limited only by structure around the door frame, which can be up to 180° from the closed position.
Referring now to the drawings, wherein like reference numerals designate corresponding or similar elements throughout the several views, an embodiment of a door operator is shown in
Referring to
The back plate 30 is securely mounted to the upper edge of the door frame 24 using mounting screws 50, or other fasteners. The back plate 30 extends generally horizontally with respect to the door frame 24. The motor assembly 32, operator arm assembly 36, and controller 34 are mounted to the back plate 30. A bubble level 40 is also mounted to the back plate 30, and may therefore be integral to the back plate 30, to assist an installer in mounting the back plate 30 to the door frame 24 or surrounding structure horizontally. The level 40 may be attached to the back plate 30 with fasteners or adhesive, and a recess 42 may be machined into the back plate 30 to receive the level 40. An installer may use the integral level 40 to adjust the back plate 30 such that the level 40 is “level” before mounting the back plate 40 to the door frame 24. The level 40 may be considered “level,” for example, when the bubble indicates that the level 40 is substantially or completely horizontal (as shown in
A cover (not shown) may be attached to the back plate 30 to surround and enclose the components of the door operator 20 that are within the limits of the back plate 30 to reduce dirt and dust contamination, and to provide a more aesthetically pleasing appearance. It is understood that although the back plate 30 is shown mounted directly to the door frame 24, the back plate 30 could be mounted to the wall 28 adjacent the door frame 24, concealed within the wall 28 or door frame 24, or mounted to the door 22 with the operator arm assembly 36 mounted to the door frame. Concealed door operators 20 are well known in the art of automatic door operators.
The motor assembly 32 includes an electric motor 52 and a gear train 54, which may include a planetary gear, mounted to the back plate 30 with a mounting bracket 56 and bolts 58. The motor 52 is a conventional 3 phase AC electric reversible motor with a motor drive shaft 60. A portion of the drive shaft 60 extends from the housing of the motor 52. The motor 52 is reversible such that the rotation of the motor 52 in one direction will cause the drive shaft 60 to rotate in one direction and rotation of the motor 52 in the opposite direction will cause the drive shaft 60 to rotate in the opposite direction. Such motors are widely commercially available and the construction and operation of such motors are well known; therefore, the details of the motor 52 are not described in specific detail herein. A suitable motor for use in the door operator 20 is available from Brother of Somerset, N.J., as model no. BHLM15L-240TC2N, which is a 240 volt motor providing 1/50 HP and a gear ratio of 240:1.
It is understood by those skilled in the art that the electric motor 52 may be selected and sized according to the dimensions and weight of the hinged door 22, and may include a gear train 54 disposed within a casing and include a gear train input shaft (not shown) coupled to the drive shaft 60 of the motor 52. An intermediate shaft 70 that is the output of the gear train 54 is coupled to the gear train input shaft. The gear train 54 may provide a proper reduction in output drive of the motor 52 necessary to move the hinged door 22 at an appropriate speed.
The controller 34 regulates the operation of the motor 52 and thus regulates the opening and closing of the door 22. The controller 34 is in communication with the motor 52, which is adapted to receive signals from the controller 34. Such communication may be via electrical wire 72. The controller 34 includes a suitable microprocessor for controlling the operation of the motor 52 and functions to generate appropriate signals to the motor 52 for rotating the drive shaft 60 in one direction to open the door 22 or the other direction for closing the door 22. The controller 34 may also function to maintain the door 22 in an open position for a selected period of time for enabling a person to pass through the door opening. The amount of time that the door 22 is held open may be varied and can be programmed into the controller 34 at the time of installation, or altered at any time thereafter by reprogramming the controller. The controller 34 may also be adjusted to generate signals that control the speed of the motor 52 for controlling the speed of opening the door 22. It is understood that although the controller 34 is shown mounted to the back plate 30, the controller 34 could also be housed internally within the wall 28, a ceiling, or remotely, such as in a mechanical room, for example. A suitable controller 34 for use with the door operator 20 described herein is well known in the art; one is available from Minarik Electric Co. of South Biloxi, Ill.
The controller 34 is part of an overall control system (not shown) which may include an input device (not shown) in electrical communication with the controller 34 for allowing a user to selectively control the delivery of electrical energy to the motor 52. The input device is operable to generate a door movement signal to the controller 34 which, in turn, is responsive to receiving the door movement signal to control operation of the motor 52 so as to selectively cause the motor 52 to rotate the drive shaft 60 and thereby effect powered opening of the door 22.
The input device may be of any known or desired type. For example, the input device may consist of a manual push pad wall switch for being mounted on the wall, or a post, adjacent to the door 22. This arrangement is such that a user, such as, for example, a handicapped person wanting to pass through the door opening need only to press the push pad for sending a signal to the controller 34 to open the door 22. Various other input devices are also suitable for use, including any type of switch, sensors and actuators, such as pressure pads as in a switch type floor mat and other mechanical switching devices, infrared motion sensors, radio frequency sensors, photoelectric cells, ultrasonic presence sensor switches, and the like. As a result of implementing some of these input devices, an automatically operable door may be caused to open by mere proximity of a person to the door. Such proximity may cause the door to operate by virtue of the interruption of a light beam, distortion of an electrical field, or by actual physical closing of the switch by contact with the person or in response to the weight of the person approaching the door. Consequently, the particular manner for generating a door movement signal to the controller 34 for energizing the motor 52 can be accomplished through any of numerous well known means.
The operator arm assembly 36 is provided for applying opening and closing force to the door. The operator arm assembly 36 includes an output shaft 80, an operator arm 82, a track 84, a roller 86, and the clutch assembly 38. The output shaft 80 is constrained to a vertical orientation by passing through bearings 90, 92 that are disposed in openings in a top brace 94 and a bottom brace 96 that are mounted to the back plate 30 with bolts 58. The output shaft 80 is coupled to the intermediate shaft 70 with an intermediate shaft bevel gear 98, fixed to the end of the intermediate shaft 70, that engages an output shaft bevel gear 100 to translate the direction of rotation 90 degrees. A set screw 102 secures the output shaft bevel gear 100 to the output shaft 80. However, it is anticipated that other forms of gearing and linkages may be used, such as worm gears, helical gears, rack and pinion arrangements and the like to translate the rotation 90 degrees. Alternative arrangements are feasible; for example, the orientation of the drive shaft 60 and the output shaft 80 axes may be parallel or coaxial.
The operator arm 82 is an elongated member that has one end that may be considered an arm hub 108, defining an opening 110 in which a bearing 112 is disposed, through which the output shaft 80 extends. An annular channel 114 surrounds the output shaft 80 at the arm hub 108. At the opposite end of the operator arm 82, the roller 86 is secured at an opening 116. The track 84 is mounted to the door 22, and the roller 86 rolls in the track 84 and may apply opening or closing force to the track 84 as the as the door 22 pivots.
In the embodiment shown, the bottom brace 96 also holds a door position sensor 120. As best seen in
As shown in
The operator arm 82 is secured to the output shaft 80 by the clutch assembly 38, which is also mounted to the output shaft 80. As most clearly shown in
The change in diameter between the first hub section 146 and the second hub section 148 creates a shoulder 162. The shoulder 162 is sized to abut a first friction disc 132, which abuts the operator arm hub 108. A second friction disc 134 abuts the opposite side of the arm hub 108, and accordingly the arm hub 108 is sandwiched on either side by the friction discs 132, 134. Alternatively, there may be parts (not shown) between the friction discs 132, 134 and the arm hub 108. The bearing 112 is received in openings in the arm hub 108 and the friction discs 132, 134, and encircles the output shaft 80. The plate 140 is mounted adjacent to the second friction disc 134, and has a squared opening 164 that fits around the clutch hub third section 150, which has longitudinal flat surfaces 166 interrupting the threads 152. The squared opening 164 assures that the plate 140 rotates with the clutch hub 130 and output shaft 80. The plate 140 also has an inner plate shoulder 168 sized to receive the outer diameter of the bearing 112. The spring 142 is stacked adjacent to the plate 140 and is secured to the clutch hub 130 by means of the retaining nut 144. The spring 142 may be a disc spring such as a Belleville washer, which has a slight conical shape, but other biasing means may be selected as appropriate. The retaining nut 144 is threaded onto the clutch hub third section 150. There are two retaining nut threaded radial bores 170, 172 in the side of the retaining nut 144 that may receive a retaining nut set screw 174 for preventing loosening of the retaining nut 144.
The materials of the door operator 20 may generally be expected to be metal, and in particular steel alloy, but may be as selected by one of ordinary skill in the art. Bearings that encircle rotating parts may be, for example, needle bearings; one such bearing 136 appropriate for use with the clutch assembly 38 is available from The Timken Company of Canton, Ohio, acquirers of The Torrington Company, Torrington part B-16.8. Other bearing types may be used as selected by one of ordinary skill in the art. Friction discs 132, 134 have coefficients of friction which are selected in a manner well-known to those skilled in the art, to allow reliable rotation the opener arm 82 to move with the friction discs 132, 134 under powered operation and independent of the friction discs 132, 134 when an obstacle is encountered or the door 22 is manually opened, as discussed below. The friction discs 132, 134 may be made of carbon fiber and may be a material used for automotive brake pads. One clutch assembly 38 appropriate for use in the embodiment shown in the figures herein is an Overload Safety Device as manufactured by Dalton Gear Company of Minneapolis, Minn.
In use, the door 22 may be either pushed open manually or automatically opened under power of the motor, initiated by a signal sent from an input device (not shown) to the controller. If the door 22 is to be automatically opened, the controller 34, in electrical communication with the motor 52, causes the motor 52 to begin operation which results in the motor drive shaft 60 rotating in a first direction. From the closed position as shown in
When the door 22 reaches its fully opened position, the second magnet 126 is proximate to the sensor 120, as shown in
Alternatively, the door 22 may be pushed open manually. The clutch assembly 38 with friction discs 132, 134 permits a user to push the door 22 open without having to rotate the motor drive shaft 60, which poses significant force requirements. Instead, the user must only overcome the force of static friction between one or more of the operator arm hub 108, the clutch hub 130, and the plate 140 with the friction discs 132, 134 and once the door 22 is moving, the reduced force of sliding friction between the same parts. Preferably, the clutch assembly 38 may be designed so that the amount of force required to overcome the frictional force of the discs 132, 134 and adjacent parts may be easily accomplished by an average person. The appropriate frictional force may be achieved by the selection of the spring 142 and by the amount of torque applied to the retaining nut 144. One method of applying the correct amount of torque may be by an installer adjusting the torque by trial and error to reach the setting where one or both of the friction discs 132, 134 will slide against an adjacent part when a user pushes the door 22 open, but otherwise the friction discs 132, 134 will engage adjacent parts to allow the motor assembly 32 to drive the door 22.
When the door 22 is pushed open, the sensor 120 indicates to the controller 34 that the door 22 is not in the closed position, and the controller 34 identifies that there has been no signal from the input device, meaning that the door 22 is being opened manually. The controller 34 then sends a signal to the motor 52 to rotate the motor drive shaft 60 in the direction that will close the door 22. The force applied by the person to open the door 22 exceeds the force of sliding friction in the clutch hub 130 and the operator arm hub 108, so the person can continue to open the door 22 as necessary. When the person passes through the door 22 and releases the door 22, the friction discs 132, 134 resume connection with the opener arm 82 and the door 22 begins to close immediately.
In the event of an obstruction in the path of the door movement during powered opening or closing, the force needed to overcome the static friction of the friction discs 132, 134 on the opener arm 82 may be overcome and optimally the door 22 is able to cease movement quickly without damage to the obstructing object.
The operator arm assembly 204 includes an operator arm 208, a track 82, a roller 86, a magnet holder 210, a washer 212, and a nut 214. The operator arm 208 has an arm hub 216 defining an opening 218 through which the motor shaft 206 and magnet holder 210 extend, and is similar to the operator arm 82 of
A door position sensor 240 is mounted to the back plate 30 with a bracket 242. The sensor 240 design and operation is similar to the sensor 120 of the door operator 20 of
Although the embodiments described above have been shown and described in considerable detail with respect to only a few exemplary embodiments thereof, it should be understood by those skilled in the art that it is not intended to be limited to these embodiments since various modifications, omissions and additions may be made to the disclosed embodiments without materially departing from the novel teachings and advantages. For example, some of the novel features could be used with any type of powered door operator. Accordingly, it is intended to cover all such modifications, omission, additions and equivalents as may be included within the spirit and scope of a door operator and associated methods as defined by the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.
