Door Operator

Abstract

A door operator for opening and closing an upwardly acting door and including a power unit having reversible motor means for driving the operator. The motor means is associated with a control circuit which includes upper and lower limit switches actuated when the door is in the opened and closed positions, respectively, which limit switches are connected in parallel and control the reversing of the motor rotation. The circuit also includes a reversing switch for reversing the motor rotation and door movement automatically if the door engages an obstacle during movement in the closing direction. Control means are associated with the reversing switch for deactivating same when the door is positioned closely adjacent but slightly spaced from its fully closed position to prevent undesired reversing of the door. The control means also includes means for deactivating the reversing switch when the door is positioned closely adjacent but slightly spaced from its fully opened position.

Description

FIELD OF THE INVENTION

This invention relates to a door operator for an upwardly acting door and, in particular, to a door operator having an improved control system associated therewith for causing the movement of the door to automatically reverse if the door strikes an obstruction during its closing movement. The control system includes means for overriding the reversing mechanism when the door is disposed within a small distance from its fully closed or fully opened positions.

BACKGROUND OF THE INVENTION

Persons acquainted with the operation of upwardly actuated doors having an electrical mechanism for effecting their movement are generally aware that some door operators have a safety switch whereby the direction of door movement is automatically reversed if the door engages an obstruction during its movement, particularly when such movement is in a downward or closing direction. This safety feature, as disclosed in U. S. Pat. No. 3,474,317 owned by the assignee of this application, has been provided to prevent damage to equipment and injury to personnel which might result from continued operation of the door when such objects are in the path of movement.

Door operators of this general character are often provided with switch means which prevent the door from reversing its direction of movement when the lower edge of the door bumps against the threshold. However, such switch means must be carefully set so that it operates just slightly before the door reaches the closed position.

In view of the close setting or timing of the switches used in existing operators, any small or thin object engaged by the door may promptly reverse the door's movement and send it back to its open position. In many geographical regions, it is not uncommon for snow and ice to build up quickly to the thickness of several inches directly in the path of the door, if the door remains open for a relatively short period of time. Moreover, extremely cold or extremely hot weather will sometimes cause the material forming the apron or threshold of the door opening to expand or heave upwardly as much as an inch or more and thereby cause a reversing movement of the door into its fully open position.

Under all of the foregoing circumstances, it is preferable to have the door stop at the point of contact with the obstruction, be it snow, a child's toy or a distorted threshold, even though there might be a space of an inch or two between the threshold and part of the lower edge of the door. In this position, the door would at least block the entrance of most of the bad weather or prevent trespassers from entering.

There are times when a door will engage an obstruction while it is being opened. In such case, it is at least desirable that the door should continue its movement in the opening direction after such a temporary stop. That is, even though the door will reverse its direction and move to the open position after it is stopped by a safety switch while being closed, it is not desirable to have the reverse situation, namely to have the door return to the fully closed position after it has been stopped by an obstruction while being opened. For one reason, where the door can be operated by a remotely controlled radio-frequency signal, it is possible for a stray signal of the same frequency to reverse the door movement after the emergency stop and while the object is still beneath the door.

It is also possible for a relay in a remote transmitter to "hang up" in the closed position, or for the inexperienced person to continue to hold the manual switch in the closed position throughout the cycle of the closing operation of existing operators. It is, therefore desirable to have a switching mechanism which must first be fully released (or opened) and then closed for a second time before the door will reverse its direction of movement. Moreover, it is desirable that the switching mechanism be arranged so that the door will then open fully and come to a stop in the open position. On the other hand, if the door is stopped during its opening movement by an obstruction, then it is desirable that repeated operations of the manual switch or remote relay will merely cause the door to first stop and then move upwardly in small increments until it reaches the fully opened position before it can be reversed in its direction of movement toward the closed position.

Accordingly, the objects and purposes of the invention have been to provide a control switch circuit and mechanism for a motorized door opener capable of overcoming the problems and achieving the results set forth above.

A further object of the invention has been the provision of a switch circuit and mechanism, as aforesaid, which is completely foolproof in operation, which is simple in construction, which can be adapted to existing mechanisms for effecting motorized operation of doors and which does not interfere in any way with the normal, manual or remote control conventionally used for energizing the electrical system whereby the door is opened or closed.

A still further object of the invention has been the provision of a door operator including therein a switch circuit and mechanism, as aforesaid, which causes reversing of the door movement when the door strikes an obstruction during movement in its closing direction by sensing the torsional reaction imposed on the motor, with the torsional reaction being used to activate a reversing switch to thus cause reverse rotation of the motor.

Still a further object of the invention has been the provision of a switch circuit and mechanism, as aforesaid, wherein a mechanically-actuated override mechanism is associated with the reversing switch for deactivating the switch when the door is spaced a small distance from either its fully opened or fully closed position to prevent undesired reversing of the door movement when the door is closely adjacent said positions.

Another object of the invention has been the provision of a switch circuit and mechanism, as aforesaid, which deactivates the reversing switch for a small distance of travel as the door moves away from its fully opened or fully closed position to permit the motor to develop the required power necessary to get the door in motion without causing activation of the reversing switch.

Other objects and purposes of this invention will be apparent to persons familiar with this type of equipment upon reading the following specification and examining the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an upwardly acting door and of the door operator associated therewith.

FIG. 2 is a perspective view of the door operator constructed according to the present invention and particularly illustrating the power unit and the drive mechanism connected between the power unit and the door.

FIG. 3 is an enlarged, perspective view of the power unit illustrated in FIG. 2, same being illustrated with the housing removed.

FIG. 4 is an exploded, perspective view of the power unit illustrated in FIGS. 2 and 3.

FIG. 5 is an end view of the control system, same being taken substantially from the right side of FIG. 3.

FIG. 6 is a sectional, elevational view taken substantially along the line VI--VI of FIG. 5.

FIG. 7 is a fragmentary, sectional, elevational view taken substantially along the line VII--VII of FIG. 5.

FIG. 8 is a sectional, elevational view illustrating therein the reverse side of the control system illustrated in FIG. 5.

FIG. 9 is a fragmentary, elevational view taken partially in cross section and illustrating therein the torsional mounting arrangement between the motor and the housing.

FIG. 10 is a diagrammatic sketch of the circuitry associated with the motor and switch mechanism of the present invention.

Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words "rightwardly" and "leftwardly" will designate directions in the drawings to which reference is made. The words "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.

SUMMARY OF THE INVENTION

In general, the objects and purposes of the present invention are met by providing a door operator which includes a reversible electric motor drivingly connected to the door for moving same between a closed vertical position and an opened horizontal position. A control circuit is associated with the motor and includes suitable switching structure for controlling the motor operation. Upper and lower limit switches are connected to the motor and are controlled by the door when same is in its fully opened and fully closed positions, respectively, for causing deenergization of the motor when in these positions. The control circuit also includes a reversing switch for causing the motor rotation to be automatically reversed when the door strikes an obstruction during its closing movement for causing the door to return to its open position. Suitable override structure is associated with the reversing switch for deactivating same when the door is spaced within a predetermined distance from its fully opened or fully closed positions. The override structure is effective whether the door is moving away from or toward its fully opened or fully closed positions, thus permitting the motor to generate the power necessary to get the door in motion when it is moving away from one of its extreme positions while also permitting the motor to be stopped when the door is moving toward one of its extreme positions. The motor is preferably mounted on a rotatable structure which is angularly displaceable when a torque reaction of predetermined magnitude is imposed on the motor to thus cause activation of the reversing switch.

DETAILED DESCRIPTION

FIG. 1 illustrates therein a door operator 11 which may be manually or remotely controlled for opening and closing an upwardly acting door 12. The door 12, in the illustrated embodiment, has several horizontally hinged sections having rollers mounted thereon for engagement with L-shaped side rails 14 for guiding the movement of the door between a substantially vertical closed position wherein it closes an opening formed in the wall 13, and a substantially horizontal open position. The structural details of the door 12 and of the side rails 14 are conventional.

The door operator 11, as illustrated in FIGS. 2-4, includes an elongated guide rail 16 stationarily mounted above and extending substantially transversely from the opening formed in the wall 13. The guide rail 16 has a carriage 17 slidably mounted thereon and pivotally interconnected to the door 12 by means of an intermediate arm 18. A substantially endless drive member 19, particularly a chain, is disposed adjacent and extends substantially along the rail 16 and is connected to the carriage 17 for slidably moving same along the rail 16. The drive chain 19 is engaged at one end thereof with a driven sprocket 21 which is rotatably supported on the wall 13 directly adjacent the upper portion of the opening therein. The other end of the drive chain 19 is engaged with a drive sprocket 22 which is nonrotatably interconnected to a driven pulley 23. An endless drive belt 24 drivingly connects the pulley 23 to a driving pulley 26 which is nonrotatably secured to the shaft 27 of a conventional reversible electric motor 28. The motor 28 comprises a portion of the power unit 29.

The power unit 29 includes a housing 31 which, as illustrated in FIG. 4, has substantially channel-shaped top and bottom members 32 and 33 fixedly interconnected by substantially channel-shaped side members 34 and 36. The housing is closed by opposed end walls 37 and 38.

The casing of the motor 28, which is disposed within the interior of the housing 21, is fixedly mounted on a sensor bracket 39, being secured thereto by bolts 41 (FIG. 9). The sensor bracket 39 is in turn rotatably supported on a lower motor mounting bracket 42 which has substantially channel-shaped portions 43 (FIG. 4) on the opposite edges thereof which are adapted to be disposed over the upwardly extending legs 44 formed on the opposite edges of the bottom channel-shaped housing member 33. The channel-shaped portions 43 of the lower motor mounting bracket 42 have elongated slots therein through which extend locking screws 46 for permitting the position of the motor to be adjusted longitudinally of the housing whereby the tension on the drive belt 24 can thus be selectively adjusted. A further motor mounting bracket 47 is associated with the upper end of the motor 28 and is fixedly and adjustably connected to the upper channel-shaped housing member 32 in a substantially similar manner.

The sensor bracket 39 and the lower motor mounting bracket 42 are separated from one another by means of an intermediate annular plastic washer or bearing 48 (FIG. 9) to permit the sensor bracket 39 and the motor 28 mounted thereon to rotate relative to the motor mounting bracket 42. The sensor bracket 39 also has a hub portion 49 fixedly secured thereto and projecting downwardly through an opening formed in the motor mounting bracket 42 (FIG. 9), which hub portion has one end of a rodlike torque limiting spring 51 fixedly secured thereto. The other end of the torque limiting spring 51 extends through an elongated slot 52 formed in the housing end wall 37 and disposed for engagement with a toothed rack 53.

The sensor bracket 39 also has a substantially L-shaped sensor rod 54 (FIG. 3) movably mounted thereon, which rod includes substantially perpendicular legs 56 and 57. The leg 56 is rotatably supported on a pair of spaced ears 58, and a spring 59 coacts between the bracket 39 and the sensor rod 54 for normally urging said rod 54 to rotate about the axis of the leg 56. The spring 59 urges the sensor rod 54 to rotate in a substantially counterclockwise direction as appearing in FIG. 3.

The power unit 29 includes a drive shaft 61 rotatably supported on the housing 31 and having the drive sprocket 22 and driven pulley 23 nonrotatably secured to the upper end thereof. The drive shaft 61 is threaded over the lower portion thereof and has upper and lower control nuts 62 and 63, respectively, threadably engaged therewith. The nuts 62 and 63 each have their peripheries disposed closely adjacent an elongated stationary guide flange 64, which flange prevents the nuts 62 and 63 from rotating so that the nuts thus travel linearly along the threaded portion of the shaft 61 in response to shaft rotation. The lower nut 63 is positioned for engagement with the free end of the leg 57 of the sensor rod 54 when the lower nut 63 is linearly moved into its lowermost position. The purpose of this positional arrangement will be explained hereinafter.

The power unit 29 also includes a control system 66 mounted on a stationary panel 67 which is positioned between the drive shaft 61 and the motor 28. The control system 66 includes a control lever 68 (FIG. 7) having its upper end pivoted at 69 to a stationary tab 71. The lower end of the control lever 68 has a laterally extending projection 72 which extends outwardly so as to be contacted by the lowermost nut 63. Control lever 68 also has an actuating portion 73 disposed adjacent the free end thereof, which portion 73 projects rearwardly beneath the panel 67 and is disposed in engagement with the actuating lever 74 of a normally closed limit switch 76. The switch 76 is opened when the door is in its horizontal open position and thus will hereinafter be referred to as the "up" limit switch.

The control system 66 also includes an "open" override lever 77 (FIG. 6) pivoted at 78 on the stationary tab 79. The override lever 77 is pivoted substantially in the center portion thereof and has a laterally extending projection 81 formed on the lower free end thereof, which projection 81 is disposed for contact with the lower nut 63 as same is moved downwardly. However, the projection 81, as illustrated in FIG. 6, is disposed slightly above the projection 72 formed on the control lever 68.

The upper free end of the override lever 77 is, as illustrated in FIG. 6, connected to a spring 82 which has its other end connected to a stationary flange 83, whereby the spring 82 thus normally resiliently urges the lever 77 in a counterclockwise direction into the position illustrated in FIG. 6. The override lever 77 has the upper free end thereof positioned adjacent, but spaced outwardly from beneath, the actuating lever 84 of a normally closed reversing switch 86.

Control system 66 includes still a further lever, namely the "closed" override lever 87, same being pivoted at 88 on the stationary tab 89. The upper free end of override lever 87 has a laterally extending projection 91 formed thereon positioned for engagement by the upper nut 62 when same is moved upwardly towards its extreme position. Override lever 87 has a transversely projecting flange 92 formed on the lower free end thereof, which flange 92 overlaps and is engaged by the upper free end of the "open" override lever 77. The "closed" override lever 87, due to engagement thereof with the upper free end of the "open" override lever 77, is thus normally maintained in the position illustrated in FIG. 6 and is continually resiliently urged in a clockwise direction (as illustrated in FIG. 6). Movement of the upper free end of the override lever 77 in a direction (clockwise in FIG. 6) in opposition to the resilient urging of the spring 82, such as would be caused by engagement of the lower nut 63 with the projection 81 or engagement of the upper nut 62 with the projection 91, causes the free upper end of lever 77 to be pivotally moved into a position wherein it is disposed directly under the actuating lever 84 of the normally closed reversing switch 86, whereby the lever 77 thus maintains the reversing switch 86 in an open position.

The actuation of the reversing switch 86 is normally controlled by means of a U-shaped reversing lever 96 (FIG. 5) which is pivoted at 97 on the panel 67. Reversing lever 96 has an upper leg portion 98 provided with a transverse tab 99 adjacent the free end thereof, which tab is normally maintained in engagement with the actuating lever 84 of the reversing switch 86. A spring 101 is connected between the tab 99 and a stationary flange 102 for normally resiliently urging the lever 96 in a counterclockwise direction as illustrated in FIG. 5, whereby the tab 99 normally engages the actuating lever 84 to thus maintain the reversing switch 86 in an open position.

The U-shaped reversing lever 96 also includes a lower leg portion 103 which is disposed adjacent and partially overlaps a substantially L-shaped slot 104 formed in the panel 67. The lower leg portion 103 has an enlargement 106 adjacent the free end thereof which results in the formation of a shoulder 107. The enlargement 106, when the lever 96 is urged by spring 101 into its normal position (as illustrated in FIG. 5), is positioned to at least partially overlap the L-shaped slot 104 in the vicinity of the junction between the horizontally and vertically extending portions of the slot. The slot 104, as illustrated in FIGS. 3 and 5, has a size which permits the leg 57 of the L-shaped sensor rod 54 to extend therethrough, with the movement of the leg 57 within the horizontal portion of the L-shaped slot 104 being controlled by the enlargement 106 when same is positioned to overlap the slot as illustrated in FIG. 5.

The leg 57 of the sensor rod 54 engages the actuating lever 108 of a normally closed limit switch 109 when the leg 57 is moved into the upper end of the vertically extending portion of the slot 104. The limit switch 109 is opened when the door is moved into its lowermost or closed position, and thus switch 109 will be hereinafter referred to as the "down" limit switch.

The circuitry for the control system 66 is diagrammatically illustrated in FIG. 10 and specifically includes a start circuit 111 connected in parallel with a motor control circuit 112, which circuits are connected to a suitable potential source, such as a conventional 120 volt alternating current source. The start circuit 111 includes a transformer 113 which has the coil thereof connected in series with the coil 114 of a conventional flip-flop relay 115. A conventional start switch 116, which is normally open and may be a manual push-type switch or a remotely controlled switch, is connected in series with the relay coil 114 and the transformer 113. Further, the normally closed reversing switch 86 is connected in parallel with the start switch 116.

The motor control circuit 112 includes therein a pair of parallel circuits which are connected to the field of the motor 28 for permitting reverse rotation of the motor in a conventional manner, which parallel circuits contain therein the up and down limit switches 76 and 109, respectively. The flip-flop relay armature or switch 117 is connected in the main power circuit and permits alternate energization of the parallel motor circuits. Further, the up limit switch 76, when moved into its open position, is designed to coact with a circuit having a conventional electric light 118 disposed in series therewith so that the light will thus be energized whenever the door is in the open position and the up limit switch 76 is opened.

OPERATION

The operation of the door operator according to the present invention will be briefly described to insure a complete understanding thereof.

For purposes of explanation, it will be assumed that the door is in a partially opened condition and is moving downwardly toward its closed vertical position. When in this position, the control system 66 will be disposed in the position illustrated in FIGS. 3 and 5-7, and the electrical circuit will be disposed in the condition illustrated in FIG. 10. In this condition, spring 101 urges the tab 99 of reversing lever 96 into engagement with the actuating lever 84 to thus maintain reversing switch 86 in its open position. The up and down limit switches 76 and 109, respectively, will be in their closed positions, and the relay switch 117 will be connected in series with the down limit switch 109 to permit energization of motor 28 to thus move the door downwardly toward its closed position. When the door is being moved downwardly, the drive shaft 62 is rotated in such a direction that the nuts 62 and 63 are moved axially upwardly.

If the downwardly moving door strikes an obstruction, such as a vehicle, prior to reaching its fully closed position, which obstruction prevents further downward movement of the door, then the rotation of the motor shaft 27 is effectively stopped. The motor thus imposes an opposite torsional reaction on the casing of the motor substantially in the direction of the arrow A (FIG. 3). When the torsional reaction reaches a predetermined magnitude so as to overcome the effect of spring 51, then the motor 28 and of the sensor bracket 29 are rotated whereby the leg 57 of the sensor rod 54 is moved into contact with the stop 107, causing the lower leg portion 103 of reversing lever 96 to be cammed downwardly (clockwise in FIG. 5). This angular displacement of reversing lever 96 causes the tab 99 to be moved downwardly away from the actuating lever 84, whereupon the reversing switch 86 is thus permitted to return to its normally closed position. This causes energization of relay coil 114 whereby relay switch 117 is shifted so as to be connected in series with the normally closed up limit switch 76 (as illustrated by dotten lines in FIG. 10). The motor 28 is thus energized to rotate in the reverse direction to cause the door to be moved upwardly to return it to its open horizontal position. As the rotation of motor 28 is being reversed, the spring 59 causes the leg 57 of L-shaped sensor rod 54 to be moved vertically upwardly into the upper end of the vertically extending portion of the L-shaped slot 104, thereby retaining the leg 57 in the dotted line position illustrated in FIG. 7. This permits the spring 101 to return the lever 96 to its normal position wherein the enlargement 106 overlaps the slot 104 and wherein the flange 99 engages the actuating lever 84 and causes the reversing switch 86 to again be opened. Movement of leg 57 into the vertical portion of slot 104 also causes leg 57 to engage lever 108 whereby down limit switch 109 is opened.

As the door moves upwardly toward its open position, the control nuts 62 and 63 move axially downwardly along the threaded shaft 61. As the door approaches but is spaced a small predetermined distance from its fully opened position, the lower nut 63 contacts the projection 81 of the override lever 77 and swings same (clockwise in FIG. 6) in opposition to the urging of the spring 82, whereupon the upper free end of lever 77 is thus moved into a position wherein it is disposed directly beneath the actuating lever 84 of the reversing switch 86. In this position, the lever 77 holds the actuating lever 84 in its uppermost position to thus maintain the reversing switch 86 in an open position irrespective of the position of the reversing lever 96. The door continues to travel toward its fully opened position, during which movement the lower control nut 63 continues to move downwardly whereupon the nut 63 engages the free end of the leg 57 of the sensor rod 54 and moves same vertically downwardly until the leg 57 is disposed adjacent the lower end of the vertical portion of the L-shaped slot 104. The torque limiting spring 51 then causes the motor 28 and sensor bracket 39 to be rotated in a direction to return the leg 57 to the opposite end of the horizonal portion of the L-shaped slot 104, namely to the leftward end of the horizontal portion substantially as illustrated in FIG. 5. At the same time, the nut 63 contacts the projection 72 of the control lever 68 whereby same is pivotally moved (clockwise in FIG. 6) toward the actuating lever 74 to thus depress same in opposition to the urging of the internal spring disposed within the limit switch 76, thereby opening the normally closed limit switch 76 and stopping the motor 28. Since the reversing switch 86, as explained above, is deactivated during the last portion of movement of the door as it approaches its fully opened position, this thus permits the motor to exert a greater driving force on the door to insure that it is moved into its fully opened position. Also, simultaneous with the movement of the door into its fully opened position and the opening of the "up" limit switch 76, the switch 76 is also connected in series with the light 118 to thus cause energization of the light 118 whenever the door is in its fully opened position.

When the door is to be closed, the start switch 116 is momentarily closed to cause a momentary energization of the relay coil 114, whereby the relay switch 117 is shifted to be connected in series with the closed "down" limit switch 109. This causes energization of motor 28 so that the door is then moved toward its closed vertical position. As the door moves away from its fully opened position, the lower control nut 63 travels upwardly and thus initially disengages the control lever 68, whereby the "up" limit switch 76 is thus permitted to return to its normally closed position. This thus de-energizes the light 118. Further upward movement of lower control nut 63 causes same to also disengage the lower override lever 77, whereby spring 82 returns lever 77 to the position illustrated in FIG. 6 so that the lever 77 is no longer disposed in engagement with the actuating lever 84 of the reversing switch 86. However, the reversing switch 86 is still maintained in an open position due to the reversing lever 96. The door continues to move downwardly toward its closed vertical position and, assuming that the door contacts no obstruction, this movement continues until the upper control nut 62 contacts the projection 91 of the upper override lever 87. This contact of the upper control nut 62 with the projection 91 occurrs when the door is spaced a small predetermined distance from its fully closed position, such as when within four to eight inches therefrom. The upper control nut 62 then causes lever 87 to swing (counterclockwise in FIG. 6) toward the upper end of lower override lever 77, and thus causes the lower override lever 77 to be swing-ably displaced (clockwise in FIG. 6) in opposition to the urging of the spring 82 so that the upper free end of override lever 77 is again moved into a position wherein it is disposed directly below and in engagement with the actuating lever 84 to thus maintain the reversing switch 86 in its open position. The door will then continue downwardly until the lower edge of the door contacts the threshold of the door opening. At this time further downward movement of the door is effectively restrained. A torsional reaction is thus imposed on the casing of the motor so that the motor and sensor bracket 39 are rotated, which in turn causes leg 57 of sensor rod 54 to be moved along the horizontal portion of the L-shaped slot from one end to the other end thereof, whereupon spring 59 urges the leg 57 upwardly into the vertical portion of the slot 104. As the leg 57 is urged upwardly into the vertical portion of the slot, the leg 57 contacts the actuating lever 108 of the "down" limit switch 109, thereby opening the limit switch and de-energizing the motor 28.

As described above, the reversing switch 86 is rendered ineffective during the last portion of travel of the door, particularly as the door is positioned closely adjacent its fully closed position, whereby increased drive torque can thus be applied to the door to insure that same is moved to a fully closed position. This is especially critical in situations where ice or snow may become positioned on the threshold when the door is opened and would otherwise prevent the door from being moved to its fully closed position or, as an alternative, would cause a reversing of the door.

With the door in its fully closed position, the door is opened by momentarily closing the start switch 116, whereby relay coil 114 is again momentarily energized so that the relay switch 117 is again shifted to thus place same in series with the closed "up" limit switch 76. This energizes motor 28 to cause same to rotate in a reverse direction so that the door is then moved upwardly. As the door is initially moved upwardly away from its closed vertical position, the upper control nut 62 will again move axially downwardly so that, when the door has been raised said predetermined distance away from its fully closed position, the upper override lever 87 and the lower override lever 77 will be returned to their normal positions (as illustrated in FIG. 6) due to the urging of the spring 82. The door will continue to travel upwardly, and the control nuts 62 and 63 will likewise continue to move axially downwardly until the door again approaches its fully open position. This operation of the door is thus identical to the operation as explained above.

As is readily apparent from the operational description set forth above, the control system of the present invention, as incorporated into the overall door operator, thus provides a reversing switch which results in the door being automatically reversed and moved upwardly toward its open position in the event the door strikes an obstruction during its downward travel which prevents further downward movement of the door. Further, this reversing in the movement of the door can be adjusted to occur at a desired force level merely by adjusting the magnitude of the torsional resistance imposed on the motor housing by the spring 51. Thus, the reversing of the door can be made to occur when a relatively minor obstruction is encountered so as to thus not cause damage to either the obstruction or the door. On the other hand, since the reversing switch 86 is rendered ineffective when the door is positioned closely adjacent its fully opened or fully closed positions, this thus enables a substantially greater closing force to be imposed on the door to insure that the door is moved into its fully opened and fully closed positions. Further, if the door should encounter an obstruction when it is closely adjacent one of its extreme positions, such as might occur due to the presence of a layer of ice disposed over the threshold of the door opening, the door will thus remain in this position and the motor will be deactivated, even though the door has not travelled all the way to its normal fully closed position. The present invention thus prevents undesired reversing of the door in situations where the door is within a few inches of its fully closed position. Also, since the reversing switch is also inactivated during the initial movement of the door away from its fully closed or fully opened positions, this thus prevents reversing of the door and permits development of the larger driving force necessary to get the door in motion.

Further, since the leg 57 of the sensor rod 54 maintains the "down" limit switch 109 in an open position when the door is being moved upwardly, this prevents the door movement from being reversed when the door is being moved upwardly. The present invention permits reversal of the door travel direction to occur only when the door is being moved downwardly, so that upon reversal the door will thus be automatically moved upwardly. The encountering of an obstruction as the door moves upwardly merely causes a stopping of the door, and will not cause an undesired downward movement of the door.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangemnt of parts, lie within the scope of the present invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a device including a reversible electric motor connectible to a source of electric potential for opening and closing a door connected to the motor by drive means, the motor being rotatable in a first direction when the door is being moved toward a first end position wherein it is closed, the motor being rotatable in a second direction opposite said first direction when the door is being moved toward a second end position wherein the door is open, and a mechanism for controlling the motor rotation, said mechanism comprising:

first circuitry means including a first limit switch for connecting the motor in series with the source of potential for rotating the motor in said first direction;

first means responsive to movement of said door for opening said first limit switch as said door moves into said first end position;

second circuitry means including a second limit switch for connecting the motor in series with the source of potential for rotating the motor in said second direction;

second means responsive to movement of said door for opening said second limit switch as said door moves into said second end position;

relay means alternately connecting said source to one of said first and second circuitry means;

third circuitry means connected to said source for operating said relay means, said third circuitry means including a first normally open switch for permitting selective actuation of said relay means to permit said door to be selectively moved between its open and closed position;

said third circuitry means further including reversing switch means connected in parallel with said first normally open switch for operating said relay means independently of said first switch for permitting control of said motor during movement of said door between said end positions;

third means cooperating with said reversing switch means for normally maintaining same in an open position as said door is being moved between said end positions while permitting movement of said reversing switch means to a closed position when the movement of said door is interrupted before it reaches said end positions; and

fourth means cooperating with said reversing switch means for maintaining same in an open position whenever said door is within a small predetermined distance from either of said end positions to thereby override and deactivate said reversing switch means;

said reversing switch means when moved to a closed position due to said door striking an obstruction causing the motor to be reversed when the door is moving toward said first end position, said reversing switch means causing said motor to be stopped when the door is being moved toward its second end position.

2. A device according to claim 1, wherein said third means includes mounting means connected to said motor and mounting same for limited rotational movement of said motor in a direction substantially about the axis of the motor shaft, said mounting means including torsional resisting means imposing a torque of predetermined magnitude on said motor for preventing rotation thereof so long as the torsional resistance opposed on said motor is less than said predetermined magnitude, said mounting means also including a control member positioned for coaction with said reversing switch means for causing closure of said reversing switch means when the torsional resistance imposed on said motor is sufficient to cause rotational movement thereof.

3. A device according to claim 1, wherein said reversing switch means comprising a normally closed switch, said third means including first link means coacting with said normally closed reversing switch for normally maintaining same in an open position during movement of the door between its open and closed positions, said third means also including torsional mounting means for interconnecting the casing of said motor to a stationary housing, said torsional mounting means maintaining said motor casing stationary so long as the reaction torque imposed on said motor casing does not exceed a predetermined magnitude, said torsional mounting means permitting rotational displacement of said motor casing when the torsional reaction imposed thereon exceeds said predetermined magnitude, such as caused by the door striking an obstruction, and said third means further including second link means coacting between said torsional motor mounting means and said first link means for causing actuation of said first link means to permit said reversing switch to close whenever the reaction torque on said motor exceeds said predetermined magnitude.

4. A device according to claim 3, wherein said fourth means includes linkage means movable into engagement with said reversing switch for maintaining same in an open position whenever said door is within said predetermined distance from either of said end positions to thus prevent closure of said reversing switch.

5. A device according to claim 4, wherein said second link means is positioned for engaging and actuating said first limit switch to move same to an open position when said door is disposed within said predetermined distance from said first end position.

6. A power unit for controlling the movement of a door between a first end position wherein the door is closed and a second end position wherein the door is open, the power unit including reversible electric motor means rotatable in a first direction for causing movement of said door in a closing direction toward said first end position and rotatable in a second direction opposite said first direction for causing movement of said door in an opening direction toward said second end position, comprising the improvement wherein said power unit includes:

reversing means coacting with said motor means for causing the rotation thereof, when said door is being moved in a door closing direction, to be automatically reversed whenever the door strikes an obstruction preventing further movement of said door, whereby said door is automatically returned to its open position;

first override means coacting with said reversing means for permitting selective deactivation of said reversing means to thus prevent reversal in the rotation of said motor means, said first override means being normally maintained in an inoperative position and being moved to an operative position wherein it deactivates said reversing means only when said door is spaced within a first predetermined distance from said first end position;

second override means coacting with said reversing means for selectively deactivating said reversing means to prevent reversal in the rotation of said motor means, said second override means being normally maintained in an inoperative position and being moved to an operative position only when said door is spaced within a second predetermined distance from said second end position; and

actuating means responsive to the movement of said door between its end positions for causing the first and second override means to be individually moved to their operative positions when the door is disposed within said first and second predetermined distances from said first and second end positions, respectively.

7. A unit according to claim 6, wherein said reversing means includes a reversing switch operatively associated with said motor means; and

torque responsive means coacting between said reversing switch and said motor means for causing actuation of said reversing switch whenever the reaction torque imposed on said motor means exceeds a predetermined magnitude.

8. A unit according to claim 7, wherein said torque responsive means includes means mounting the casing of said motor means for permitting rotational displacement thereof when the reaction torque imposed on said motor means exceeds a predetermined value.

9. A unit according to claim 6, further including:

first circuitry means including a limit switch for connecting the motor means in series with a source of potential for rotating the motor means in one of said first and second directions;

second circuitry means including a second limit switch for connecting the motor means in series with the source of potential for rotating the motor means in the other of said first and second directions;

relay means alternately connecting said source of potential to one of said first and second circuitry means;

said reversing means including a reversing switch electrically connected to said relay means for permitting control of same, and link means coacting with said reversing switch for normally maintaining same in an open position to thus prevent reversing of said motor means; and

said reversing means further including torque responsive means operatively connected between said motor means and said link means and responsive to the reaction torque imposed on said motor means exceeding a predetermined value for causing actuation of said link means whereby said reversing switch is thus moved to a closed position to cause energization of said relay means.

10. A device according to claim 9, wherein said first and second override means engage said reversing switch and hold same in said open position when said first and second override means are moved to their respective operative positions, thereby preventing closure of said reversing switch when said door is within said predetermined distance from either of said end positions.

11. A unit according to claim 9, wherein said first and second override means includes first and second levers, respectively, mounted for swingable movement between said operative and inoperative positions, and resilient means coacting with said levers for normally maintaining same in said inoperative positions, said first and second levers when moved into said operative position engaging said reversing switch for maintaining same in an open position;

said actuating means being movable between first and second extreme positions in response to movement of said door between said first and second end positions, respectively, said actuating means engaging said first lever when it approaches said first extreme position and engaging said second lever as it approaches said second extreme position, engagement of said actuating means with either of said levers causing said lever to be moved to its operative position;

said link means including lever means disposed for engagement with said reversing switch and biasing means coacting with said lever means for normally urging same into engagement with said reversing switch for maintaining same in an open position; and

said torque responsive means including a control link member actuated in response to imposition of a reaction torque on said motor means exceeding said predetermined value and disposed for actuating said lever means for moving same in opposition to said biasing means for enabling said reversing switch to move to a closed position.

12. A unit according to claim 11, wherein there is provided a substantially stationary housing means, and said torque responsive means including means mounting said motor means on said housing means for permitting rotational displacement of said motor means relative to said housing means in response to imposition of a reaction torque on said motor means in excess of said predetermined value, said control link member being connected to the casing of said motor means and angularly displaceable therewith when the reaction torque on said motor means exceeds said predetermined value.

13. A unit according to claim 12, wherein said control link member is positioned for engaging said second limit switch for moving same to an opened position when said control link member is angularly displaced to an operative position in response to imposition of a reaction torque on said motor means in excess of said predetermined value.

14. A unit according to claim 13, wherein said actuating means, as it is moved toward its second extreme position, engages said control link member and returns same to its normal inoperative position.

15. A unit according to claim 11, further including a third pivotal lever positioned for engagement with said second limit switch, said third lever being disposed for engagement by said actuating means when same reaches its second extreme position for causing swinging movement of said third lever into engagement with said second limit switch to thus move same into an open position.

16. A power unit for controlling the movement of a closure member between a first end position wherein the closure member is closed and a second end position wherein the closure member is open, the power unit including reversible motor means rotatable in a first direction for causing movement of said closure member in a closing direction toward said first end position and rotatable in a second direction opposite said first direction for causing movement of said closure member in an opening direction toward said second end position, comprising the improvement wherein said power unit includes:

reversing means including reversing switch means coacting with said motor means for causing the rotation thereof, when said closure member is being moved in a closing direction, to be automatically reversed whenever the closure member strikes an obstruction preventing further movement of said closure member, whereby said closure member is automatically returned to its open position;

responsive means coacting between said reversing switch means and said motor means for causing actuation of said reversing switch means whenever the reaction torque imposed on said motor means exceeds a predetermined magnitude as said closure member is being moved in said closing direction;

override means coacting with said reversing means for permitting selective deactivation of said reversing means to thus prevent reversal in the rotation of said motor means, said override means being normally maintained in an inoperative position and being moved to an operative position wherein it deactivates said reversing means only when said closure member is spaced within a predetermined distance from one of said end positions; and

actuating means responsive to the movement of said closure member between its end positions for causing said override means to be moved to its operative positions when the closure member is disposed within said predetermined distance from said one end position.

17. A unit according to claim 16, wherein said responsive means includes means mounting the casing of said motor means for permitting rotational displacement thereof when the reaction torque imposed on said motor means exceeds a predetermined value.