What is claimed is
1. A door operator control mechanism, comprising in combination,
2. A door operator control mechanism as set forth in claim 1, wherein said load switch is connected to be responsive to the speed of movement of the door load on said motor.
3. A door operator control mechanism as set forth in claim 1, wherein said torque switch means includes a one-way clutch connected to be responsive to torque in the closing direction of movement of the door to act on said torque switch means and non-responsive to torque in the opening direction of movement of the door.
4. A door operator control mechanism as set forth in claim 1, wherein said linkage means includes a hub rotatable about an axis in accordance with door movement,
5. A door operator control mechanism as set forth in claim 1, wherein said linkage means includes a hub rotatable about an axis in accordance with movement of the door,
6. A door operator control mechanism as set forth in claim 5, wherein said first switch member is stationary,
7. A door operator control mechanism as set forth in claim 1, wherein said linkage means includes a hub rotatable about an axis in accordance with door movement,
8. A door operator control mechanism as set forth in claim 1, including a friction clutch in said linkage means,
9. A door operator control mechanism as set forth in claim 1, including a friction clutch in said linkage means,
10. A door operator control mechanism as set forth in claim 1, including arelay in said motor energization means,
11. A door operator control mechanism as set forth in claim 10, wherein said relay is an intermittently actuated relay,
12. A door operator control mechanism as set forth in claim 1, including a down limit switch connected to said motor energization means and actuable by the closed condition of the door,
13. A door operator control mechanism as set forth in claim 12, including said second switch being constructed to remain closed for a majority of movement from said second to said first position of said torque switch means.
14. A door operator control mechanism as set forth in claim 1, wherein said motor is reversible to reverse the direction of door movement.
15. A door operator control mechanism as set forth in claim 1, including disabling means connected to disable said first switch.
16. A door operator control mechanism as set forth in claim 15, wherein said disabling means includes a second switch as a part of said torque switch means,
17. A door operator control mechanism as set forth in claim 15, including a down limit switch connected to be actuated by the closed position of the door,
BACKGROUND OF THE INVENTION
Garage door operators in recent years have seen increased use because a garage door, especially the upward-acting overhead type, is heavy and difficult to manually move. The motor driven door operator and especially the remote radio controlled door operator, offers convenience to the motorist for powered opening or closing of the garage door by remote control. The very fact that the door is large, heavy and has considerable inertia, and is also motor driven, brings with it inherent problems of safety. A small child or pet might be in the doorway as the door is closing and might not observe that the door is actually closing. Also the child or pet might see the door closing and try to run out of the garage and trip or otherwise be caught under the closing door. To be a practical device the door operator must necessarily have enough force to close the door firmly so as to be able to push the door closed through a small amount of snow or leaves, for example. Also the motor must have enough force to overcome some binding or variable friction of the door on the door tracks because of improper adjustment or lubrication, in order to be a marketable door operator. It is common knowledge that most people do not keep their garage door in the best possible operating condition, not lubricating or adjusting it monthly. The average user will operate the door for years without paying attention to it and will examine the door only when it completely fails to operate. In fact, some people have been known to buy an operator only when the door has become so hard to move that they could not move it manually, and then they tried to install a door operator instead of adjusting or lubricating the door.
This human nature failing must be taken into account in the safety factor of constructing and using a door operator, especially in the downward or door closing direction. This is especially true in order to have a safe operating door in the event a pet or child should happen to become trapped under the door.
Prior systems have been suggested for providing a safety switch of a sensitive slightly moving bar along the entire bottom edge of the door so that if some obstruction were met in the downward closing movement, then this switch bar would stop the door. There are two defects to this system, one is human nature and the other is ice or snow. The snow or ice has been known to freeze the switch bar so that it cannot be moved and the careless user merely disconnects the switch and hence disconnects the safety feature in order to be able to use the door operator rather than attempting to thaw the door safety switch. The human factor enters the above problem but is also present in the fact that merely stopping the door may not be enough. The child or pet may be trapped under the door and not be able to extricate himself and may suffocate to death.
Accordingly, it is an object of the invention to provide a door operator which obviates the above-mentioned disadvantages.
Another object of the invention is to provide a door operator which automatically reverses if an obstruction is met when moving only in the downward direction.
Another object of the invention is to provide a torque switch responsive to the torque load of the door on the motor which will stop and then reverse the door movement if the door is moving only in the closing direction.
Another object of the invention is to provide a door operator reversing control with a first switch sensitive to load speed and a second switch sensitive to a single direction of load torque.
Another object of the invention is to provide a door operator reversing control wherein a torque switch is operable in the door closing direction should an overload of torque be required yet is disabled upon the normal down limit position of the door being reached.
SUMMARY OF THE INVENTION
The invention may be incorporated in a door operator control mechanism, comprising in combination, an electric motor, linkage means connecting said motor to a door to move the door between opened and closed positions, connection means to energize said motor, a load switch actuated by a change in load of the door and connected to said energization means, torque switch means connected to said energization means and including a first and second relatively movable switch member having a first switch therebetween, means providing first and second positions of said first switch member relative to said second switch member, means relatively urging said switch members from said second to said first position, torque means responsive to the closing direction of the door and acting on one of said switch members to overcomes said urging means to relatively urge said switch members from said first toward said second position, said load switch acting to provide a first signal to said motor energization means for a door stopping condition upon the door in a closing direction encountering an overload and actuating said load switch, and said first switch being actuated by said urging means inter-mediate said second and first positions to give a seconds signal to the motor energization means to establish a door opening condition subsequent to the door stopping condition by the first signal.
Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side elevational view of a door operator of the invention connected to operate a garage door;
FIG. 2 is an enlarged longitudinal sectional view through the structure of the torque switch;
FIGS. 3 and 4 are sectional views on lines 3--3 and 4-4, respectively, of FIG. 2; and,
FIG. 5 is a schematic diagram of the door operator control circuit and including a diagrammatic representation of the torque switch.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The reversing control of the present invention is susceptible of many uses, however, in order to illustrate a preferred embodiment it has been illustrated in connection with a motor operated garage door. In this connection FIG. 1 shows the door control 11 in connection with a garage door 12 which is adapted to move on a track 13 between a down or closed position shown in full lines in FIG. 1 and an up or open position 14 shown in phantom lines. A channel 15 is secured to the ceiling of the garage or other enclosure and comprises a horizontal guideway along which a carriage 16 is attached to move back and forth. The channel 15 houses a worm 17 which is rotatably driven by an electric motor 18 and appropriate mechanism contained without a housing 19. Driving connection is made between the worm 17 and the carriage 16 by means of a partial nut 20 which meshes with the worm 17. A link 21 interconnects the door 12 and the carriage 16 with this link pivotably connected to each the door and the carriage. As a result of this construction, the door moves between its open and closed positions as the carriage 16 travels back and forth along the channel 15.
FIGS. 2, 3 and 4 show enlarged details of the construction with the motor 18 illustrated schematically as having a hollow shaft through which the worm 17 coaxially extends to cooperate with the partial nut 20. The door 12 is also diagrammatically illustrated as being connected to the carriage 16 by the link 21. Linkage means 22 interconnects the motor 18 and door 12 and includes generally the worm 17, nut 20 and link 21. This linkage means also includes a friction clutch with a clutch plate 24 driven directly by the motor 18 and a clutch disc 25 carrying a clutch lining 26 frictionally cooperating with the clutch plate 24. The worm 17 has a rearward extension 27 to which a hub 28 is keyed or otherwise rotationally fixed. A nut 29 and a lock nut 30 engage the threaded end of the worm extension 27 and provide variable compressive stress on a compression spring 31. This adjusts the force between the clutch plate 24 and lining 26 to adjust the point at which the clutch will slip upon overload.
A hub bracket 34 is fixed to rotate with the hub 28. A load switch 35 is provided which is sensitive to speed; namely, the speed of movement of the door 12. The load switch 35 is on the load side of the friction clutch 24-25 so that should the door meet an obstruction which slows or stops it, the hub 28 slows or stops and this actuates the load switch 35. This load switch 35 is a centrifugally actuated switch with a switch plunger 36 radially slidably journalled in apertures in the hub bracket 34. A compression spring 37 acts between the bracket and a shoulder on the plunger 36 to urge the plunger radially inwardly so that the head 38 on the plunger is urged into engagement with an electrically conducting sleeve 39. This sleeve is coaxial with the worm axis 44 and has a flange 40 riveted by rivets 41, 42 and 43 to an insulator drive disc 45. By mounting the sleeve 39 on insulation, it is insulated from ground except when contacted by the switch plunger 36, the switch plunger 36 being grounded by its support in the metal hub bracket 34.
Torque switch means 48 includes a first switch 49 and a second switch 50. The torque switch means 48 includes first and second switch members 51 and 52, respectively, with the first and second switches 49 and 50 connected therebetween. The first switch member 51 is stationary and the second switch member 52 is movable and is connected as a part of the insulator drive disc 45. The first switch member 51 is constructed of insulation and is journalled at 53 on the hub 28. A fixed finger 54 of the housing of motor 18 engages a slot in the first switch member 51 to keep it non-rotating. The stationary first switch member 51 carries leaf spring contacts 56-59 as a part of this torque switch means. The leaf spring contact 56 cooperates with the rivet 41 as the first switch 49 for a momentary contact switch. A chord of the sleeve flange 40 is cut away at 61 to provide clearance for a moving contact blade 62 which is fixed on the insulator drive disc or second switch member 52. This contact blade 62 may be simply constructed from bare electrically conductive wire passed through holes in the switch member 52 and clinched to fasten the wire to this switch member 52. The moving contact blade 62 cooperates to short the leaf spring contacts 57 and 58 when the torque switch means 48 is in the position of FIG. 4, yet does not short or close these contacts when the torque switch means 48 is in the position of FIG. 3.
An insulator stud 65 on the second switch member 52 cooperates with shoulders 66 and 67 on the first switch member 51 to establish first and second limit positions of this second switch member relative to the first switch member 51. These first and second limit positions are shown in FIGS. 3 and 4, respectively. A gravity weight 68 is fixed to the second switch member 52 and is a weight which is off center relative to the axis 44 so that gravity acts on this weight 68 to provide a means urging the switch member 52 from the second to the first position. Accordingly, when the door control is de-energized, and the motor 18 stopped, the action of gravity urges the weight 68 downwardly to the first limit position of FIG. 3.
A one-way clutch is provided to act on the torque switch means 48. This one-way clutch 70 is provided by a torque weight 71 which is mounted in an eccentric aperture 72 in the hub bracket 34. The aperture 72 is eccentric relative to a radius 73 centrally along the hub bracket 34. The torque weight 71 is positively but loosely fastened to the hub bracket 34 by having rivets 74 and 75 securing a retainer plate 76 to the weight 71. The eccentric aperture 72 is eccentric by reason of a radial enlargement 77. When the clutch disc 25 and hub 28 are rotating in the door closing direction, this is a counterclockwise direction as illustrated in FIG. 4. Accordingly, weight 71 is thrown by inertia from the first arcuate position of the weight 71 of FIG. 3 to the second arcuate position of FIG. 4. This means that the weight 71 is moved by inertia to a clockwise position relative to the counterclockwise moving hub bracket 34. FIG. 4 illustrates that in this second arcuate position the rivet 74 moves radially outwardly into the radial enlargement 77 of the eccentric aperture 72. An outer radius 78 on the weight 71 accordingly engages the inner cylindrical surface 79 of a rim 80 on the insulator drive disc 45. This frictional contact at 78-79 acts like a sprag clutch to frictionally drive the insulator drive disc 45 in the counterclockwise direction until the insulator stud 65 engages the shoulder 67 on the stationary first switch member 51. This is what establishes the second position of this torque switch means 48 as shown in FIG. 4, despite gravity urging the weight 68 clockwise.
This torque weight 71 is only a one-way friction clutch because as shown in FIG. 3, the outer radius 78 of the weight does not touch the rim inner surface 79 when the hub bracket 34 is rotating clockwise. Instead there is a space 81 between the surfaces 78 and 79. The FIG. 3 illustrates the conditions during the opening door movement. In such condition the clutch disc 25, hub 28 and hub bracket 34 rotate clockwise as viewed in FIG. 3. Due to inertia the torque weight 71 is thrown rearwardly or to a counterclockwise first arcuate position relative to hub bracket 34. In this position rivets 74 and 75 are supported in the eccentric aperture 72 in a position to assure that the space 81 is created between weight surface 78 and rim surface 79.
FIG. 5 is a combined schematic diagram of the electrical circuit and pictorial representation of the torque switch means 48. The door control circuit 85 of FIG. 5 is adapted to be energized by an Ac source 86, for example a 115 volt Ac source, which energizes a transformer 87 having a low voltage secondary 88, with one end connected to ground 90. The voltage source 86 is also connected by means of conductors 91, 92, to energize the motor 18. This motor 18 has first and second motor windings 93, 94 and a capacitor 95 connected thereacross in order to establish reversible rotation of the motor rotor 96. The rotor 96 drives through the linkage means 22 to the torque switch 48 and to the door 12 as shown in FIGS. 1 and 2. As diagrammatically illustrated in FIG. 5, the linkage means 22 includes the friction clutch 24-25 and the one-way clutch 70 before driving the torque switch means 48.
The door control circuit 85 includes a relay 98 with a relay coil 99 acting through an armature 100, a stepping wheel 101 and a cam 102 to control actuation of contacts 103-106. These contacts are actuated closed in various sequence depending upon door opening, door open, door closing and door closed conditions. As explained below, the door control circuit 85 is illustrated in the door closing condition, and as shown contacts 103, 105 and 106 are closed. This provides direct energization to the motor winding 94 for counterclockwise rotational direction of the torque switch means 48 in FIGS. 3, 4 and 5. In the door open condition, only contact 106 is closed to provide energization to a lamp 107 illuminating the inside of a garage. In the door opening condition, contacts 103, 104 and 106 are closed with contact 105 opened, and this provides direct energization of the motor winding 93 for a clockwise rotational direction of the motor rotor 96. For the door closed condition, all contacts 103-106 are opened.
The upper end of the transformer secondary 88 connects to a terminal 109 on a terminal strip 108 which strip also contains terminal 110 and 111. This terminal 111 is grounded and terminal 110 is connected to a conductor 112 in turn connected to the lower end of the relay winding 99. A radio receiver 114 is connected for energization between terminals 109 and 111. A manually operable pushbutton switch 115 is connected between terminals 110 and 111 and the radio receiver has internal contacts 116 connected in parallel with the push button 115 between terminals 110 and 111. The conductor 112 leads to the leaf spring contacts 56 and 57 of the torque switch means 48 and also joins with a conductor 117 and through the relay contact 103 and a conductor 118 to the leaf spring contact 59. The leaf spring contact 59 is also connected through an up limit switch 119 to ground 90 and the leaf spring contact 58 is connected through a down limit switch 120 to ground 90. The centrifugal or load switch 35 is also grounded at 90 and this is provided by the physical mounting of the switch plunger 36 on the metallic part of the hub bracket 34.
The door control circuit 85 is a door motor energization means and has four conditions with door opening, door open, door closing and door closed conditions. These are set by the cam 102 acting in various sequences on the contacts 103-106. For the door closed condition all contacts 103-106 are open. To open the door, the pushbutton 115 or internal contacts 116 of the remotely controlled radio receiver 114 are closed. This energizes the relay winding 99 from the transformer secondary 88. Energization of the relay winding 99 steps the cam 102 to the door opening condition which closes contacts 103, 104 and 106. Torque to the door 12 is through the friction clutch 24-25 but not through the one-way clutch 70. In the door opening direction the one-way clutch 70 slips, i.e., is disengaged, and hence there is no frictional drive to the insulator drive disc 45. Further the driving direction of the hub bracket 34 is clockwise as viewed in FIGS. 3, 4 and 5 and accordingly, the gravity weight 68 moves the insulator drive disc 45, which is part of the second switch member 52, to the first position of FIG. 3. The hub bracket 34 is rotating about the axis 44 and centrifugal force on the switch plunger 36 urges it outwardly against the urging of the spring 37 so that it is not in contact with the conductor sleeve 39. In this respect it is similar to the diagrammatic showing of this load switch 35 in FIG. 5. This means that the conducting sleeve 39 is not grounded during this opening condition of the door. However, if the door should meet an obstruction or overload during this opening condition, then this will slow the door and slow the door load portion of the linkage means 22 subsequent to the friction clutch 24-25. If the clutch 24-25 were not provided this would slow the motor rotor itself. This slowing of the door load portion of the linkage means 22 establishes the load or centrifugal switch 35 closed. This grounds the conducting sleeve 39 and the rivets 41, 42 and 43.
The relay coil 99 is energized through leaf spring contact 59 and rivet 43 which is closed at that time on the contact 59, see FIG. 3. The relay accordingly steps to the door open condition in which contact 103 is open and this de-energizes the relay coil 99. Contacts 104 and 105 are both open to de-energize the motor 18 and only contact 106 remains close to keep the lamp 107 illuminated.
If the load switch 35 is not actuated in the door opening direction, then the door continues until it is completely open whereat the up limit switch 119 is actuated. This energizes the relay coil 99 through the conductor 118 and relay contact 103. The energization of relay coil 99 indexes the cam 102 to the door open condition whereat contacts 103, 104 and 105 are open and contact 106 is closed. With contact 103 open, the relay coil 99 is again de-energized.
To initiate the door closing movement, the push button 115 or remotely controlled receiver contact 116 is closed. This again energizes the relay coil 99 to step the cam 102 to the door closing condition in which contacts 103, 105 and 106 are closed, for the condition shown in FIG. 5. The motor 18 is energized for counterclockwise rotation and this drives through the one-way clutch 70 to the torque switch means 48, moving it to the counter-clockwise or second limit position as shown in FIGS. 4 and 5. In such condition, rivet 42 is in engagement with the leaf spring contact 59 and rivet 41 is to the left of the contact portion of the leaf spring contact 56. The torque switch means 48 may be constructed as shown in FIGS. 3 and 4, however, for clarity of operation, in FIG. 5 the leaf spring contacts 56 and 59 have been shown as having an L-shape bend to make it clear that the rivet 41 has only a momentary contact with the leaf spring contact 56 as the rivet 41 swings clockwise to the right. This would be if the door 12 should strike some overload or obstruction in the downward or closing direction of the door. Under such condition the door would slow and hence the centrifugal or load switch 35 would close. This would provide a first impulse or first signal to energize the relay coil 99. This energization would be from ground 90 through the load switch 35 through rivet 42, leaf spring contact 59, conductor 118, relay contact 103 and conductor 117 to the relay coil 99. This would index the cam 102 to a door stopped condition. With the relay 98 in this condition, contacts 104 and 105 would be open to de-energize the motor 18. This means a cessation of torque applied to the door 12 and a cessation of torque through the one-way clutch 70 to the torque switch means 48. Accordingly, the gravity weight 68 would fall downwardly, or clockwise from the position of FIGS. 4 and 5 to the position of FIG. 3. In so doing, the rivet 41 would move clockwise and momentarily engage the leaf spring contact 56. This is the first switch 49 of the torque switch means 48 and this would give a second impulse or signal to the relay 98. This would energize the relay coil 99 from ground 90, the load switch 35, conducting shell 39, rivet 41, contact blade 56, conductor 112 and through the relay coil 99 and transformer secondary 99 to ground 90. The rivet 41 goes past the contact blade 56 to clear itself so that the relay coil 99 is again de-energized.
The second switch member 52 has about a 60° arcuate movement from the second position of FIG. 4 to the first position of FIG. 3. This second impulse or signal to the relay coil 99 moves the cam 102 to the door opening condition in which contacts 103, 104 and 106 are closed. Accordingly, the door moves upwardly until the up limit switch 119 is closed. This again energizes the relay coil 99 through conductor 118 and contact 103 to change the relay 98 to the door open condition. In this condition contact 103 is open to again de-energize relay coil 99.
If the door moving in the closing direction should strike an obstruction which slows the door, such as would be caused by a child or a pet, then the present invention achieves the desirable result that the door not only stops but actually reverses and goes back to an open position. The nut 29 may be adjusted on the end of the worm 17 to adjust the torque at which the clutch 24-25 will slip and thus establish this safety reversing condition. However, if no obstruction is encountered, then the door will proceed downwardly until it closes at which time the down limit switch 120 will be actuated closed, for example, actuated by movement of the carriage 16 along the channel 15. This closing of the down limit switch 120 will energize the relay coil 99 through the second switch 50, the leaf spring contact 57, conductor 112, relay coil 99 and transformer secondary 88 to ground 90. Under these conditions of having the door properly closed, it is desired to have the safety reverse feature locked out of the circuit. The second switch 50 accomplishes this function by remaining closed for a majority of the arcuate movement of the torque switch means 48. As mentioned above, this second switch member 52 has an arcuate movement of 60° and in the preferred embodiment the second switch 50 remains closed for about 40° of this 60°. This is long enough so that the momentary contact of rivet 41 with contact blade 56, the actuation of first switch 49, has no effect upon the control circuit 85. Accordingly, this second switch 50 may be considered a disabling switch to disable the effect of the first switch 49 during this door stopping by the down limit switch 120.
It will be observed that the door control 11 has provided a safety reverse control to the door 12 to reverse the door automatically only if it is moving in a downward direction and meets an obstruction. If the door is moving upwardly and meets an overload obstruction, then the door stops but does not automatically reverse. This desirable result is achieved by using the one-way clutch 70 and the gravity actuated weight 68. The one-way clutch 70 avoids wear on the weight 71 and the rim inner surface 79 during the opening direction of door movement. It also limits drag of the weight 71 on the insulator drive disc 45 so that the gravity weight 68 may easily move downwardly and actuate the torque switch means 48. The rivets 42 and 43 do not actually act as a switch in this preferred embodiment and hence they could be joined together with a continuous conducting arc. In this preferred embodiment it is necessary only that the leaft spring contact 59 be engageable with the conducting sleeve 39 for both the first and second limit positions of the second switch member 52. Gravity acting on the weight 68 moves the second switch member 52 in a clockwise direction only during stopping in a door closing direction. The falling of weight 68 takes a finite time, for example, one-half second and during this one-half second, relay 99 will have energized and moved cam 102 to open relay contact 103 and thus de-energize the coil 99 again. Accordingly, it is ready to be re-energized as the contact rivet 41 momentarily moves past and engages the leaf spring contact 56.
The load switch 35 is actuated by a change in load of the door and in this preferred embodiment is responsive to speed movement of the door.
The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.