US2757327A - Motor control for door operation - Google Patents

Description

July 31, 1956 J. OLIVER MOTOR CONTROL FOR DOOR OPERATION 2 Sheets-Sheet 1 Filed March 9, 195-3 Hill Q INVENTUH J u SEPH L. ULIVER BY [W AT TDRNEY July 31., 1956 J.,IL. OLIVER 2,757,327

MOTOR CONTROL FOR DOOR OPERATION Filed March 9, 1953 2 Sheets-Sheet 2 IN YEN TDR JOSEPH L. ULIVER ATTDRNET United States Patent MOTOR CONTROL F 22 noon OPERATIGN Joseph L. @liver, Rochester, N. Y., assignor of one-fourth to Francis V. Spronz, Rochester, N, Y.

Application March 9, 1953, Serial No. 341,212 10 Claims. (ill. 318-265) This invention relates to power mechanism for opening and closing garage doors and the like, and more particularly to an automatic stop control therefor.

in garage door installations of the motor driven type, it has been a practice to cut off the power when the door reaches its open or closed position by limit switches operating in response to the door reaching certain set end positions. Where a sprocket and chain drive is employed, it is usual for convenience to actuate limit switches by suitably adjusted abutments carried by the chain. in such installations, it is necessary to employ a chain drive, since a positive relationship between the chain and door positions must be maintained. Such a system ofiers no protection against obstructions which may move into the path of the door, or ice and snow accumulations which may prevent the door from reaching its precise set end position.

The present invention is directed to a control for a door operated free of fixed stops, the invention being directed to apparatus adapted to sense the door reaching an end of travel abutment, and act to cut off the power. The apparatus is further adapted to permit immediate stoppage of movement of the door upon a preset increase in the resistance to movement of the door, whereby its travel may be stopped at any point. The invention is further directed to a friction drive, wherein slippage due to abnormal resistance to door movement cuts off the power and establishes a circuit in readiness for reverse movement. The invention is further directed to an effective safe control comprising few parts, sure of operation, economical to manufacture, and easy to install.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

in the drawings, wherein like reference characters indicate like parts:

Figure 1 is a prespective View of the motor drive and switch assembly;

Figure 2 is an axial sectional view taken through the clutch and cam actuator;

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 2, looking toward the left;

Fi ure 4 is a transverse sectional view taken on the line 4-4 of Figure 2, looking toward the right;

Figure 5 is a fragmentary top elevational view of the keying fingers;

Figure 6 is a top fragmentary plan view of the switch actuating lever and actuating plate; and

Figure 7 is a circuit diagram utilized to control the motor operation.

Referring to Figure 1, there is shown a reversible motor 10, which may be of the induction motor type, in which connections to the starting winding are reversed for forward and reverse rotation. The motor is connected to a reduction gear 12, which in turn drives a shaft 14 at relatively low speed. The motor and reduction gear are mounted upon a suitable frame such as 16.

Referring to Figures 26, there will be seen mounted upon the shaft a drive sprocket 18 to which is affixed a friction clutch plate 26, as by welding 22. The sprocket is connected by chains to the door opening and closing mechanism in a manner which will be understood in the art. The sprocket l8 and plate 20 are freely rotatable upon the shaft 14. Secured t0 the shaft 14 as by welding as at 24 is a clutch plate 26 having a friction facing 28, which facing frictionally engages the clutch plate 2%. The friction lining 28 is secured to the clutch plate 26 by a series of rivets 29. The end of the shaft 14 is threaded as at 30 and provided with adjustable locking nuts 32; and 34 which act through a spring 36 mounted on the shaft 1 such spring being held in compression between the nut 34 and the sprocket 18. By adjustment of the nut 34, the pressure between the friction plate 20 and the lining 23 may be adjusted, so that a predetermined slipping torque is established between the sprocket l8. and the shaft 14.

The clutch plate 2 6 is provided with arcuate raised surfaces 33 terminating at either side by short camming surfaces 40 and 42. Such raised surfaces may be stamped in the plate 26 as will be well understood in the art. Axially slidable and freely rotatable on the shaft 14 is a follower plate having projections 46, such projections having riding surfaces 48 arranged on a circle of a diameter substantially that of the diameter of the circle upon which the arcuate surfaces 38 are formed. Such projections are as high or higher than the raised arcuate surfaces 38, so that the projections may engage the plate 26 at all times. The disk 44 is provided on diametrically opposed sides thereof with pairs of spaced right angle bent fingers 5t) and 51, the axial portions 52 and 53 of which extend loosely on either side of a similar finger 54 secured to the plate 20, such finger 54 having an axially extending portion 55 extending between the axial portions 52 and 53 of the fingers 50 and 51. The plate 44 is therefore constrained to rotate with the sprocket 18, although it may freely move axially upon the shaft 14. A relatively light spring 53 is arranged upon the shaft 14 between the reduction gear box 12 and the disk 44, in order to urge the disk 44- to the left as shown in Figure 2, so that projections 4% will ride upon the raised cam surfaces 38 or the cams 4b and 42 or the intervening areas 39 between adjacent raised cam surfaces 38.

It will thus appear that so long as the sprocket 18 rotates with the shaft 14, the projections 48 of the plate 44 will ride upon the cam surfaces 38 or the intervening areas 39 of the plate 26 without relative rotation between the plates 26 or 44. Should, however, the sprocket 18 be loaded by a torque exceeding that of the friction clutch drive adjustment, such sprocket will be retarded or stopped and rotate relative to the shaft 14, causing the projections 45 to slide upon the plate 26, causing said projections either to ride off of the arcuate surfaces 38 down the cam inclines do or 42 onto the intervening surfaces 39, or conversely from the surfaces 39 and up the cam surfaces 40 and 42 onto the raised arcuate surfaces 38. Such relative motion moves the plate 44 axially a slight distance upon the shaft 14, either against the spring 58 in one direction or in consequence of the pressure of spring 58 in the other direction.

Mounted upon the reduction gear 12 is a lever 60 pivoted as at 62, such lever having an arm 64 bearing against the plate 44. The other end of the lever 60 is provided with an arm 66 which engages a switch actuating lever 68, such lever 68 being effective to actuate a switch '70 of the single pole double throw type, the switch being of the type generally referred to in the trade as a microswitch. When the disk 44 is in the position shown in Figure 2, the switch 70 is thrown to one of its closed circuit positions through the operation of the lever 60, and when the disk moves to the left of the position in which it is shown in Figure 2, that is, to the position where the projections 48 ride upon the intervening areas 39, the switch is thrown to the other of its closed circuit positions. The lever 60 is biased for counterclockwise rotation as seen in Figure 6, by a light spring 72.

Referring to the circuit diagram in Figure 7, there is shown the induction motor 10, with its field winding 74 and its starting winding 76, which generally includes a centrifugal switch. There is also shown the switch 70 previously referred to, and also a manual single pole switch 78, which switch, when momentarily closed, commences operation of the motor in one direction or the other, depending upon the position of the switch 70 and the particular circuit closed thereby. The motor derives its power from leads 80 and 82, and by reason of one or the other of the electromagnetic switches 84 and 86. Each of the switches 84 and 86 are actuated by solenoids 88 and 90, and when one or the other is energized, the switch so energized opens one circuit and closes four circuits. Such switch 84, for example, when energized, opens contacts 92, and closes contacts 94, 96, 98, and 100. On the other hand, switch 86, when energized, opens contacts 102, and closes contacts 104, 106, 108, and 110.

Power for actuation of the switches 84 and 86 is derived from a step-down transformer 112, such transformer having a low voltage secondary 114. Assuming switch 78 is momentarily closed, a circuit is established through contacts 92 and switch solenoid 90 and the lower contacts 116 of switch 70, so that contacts 102 are opened, contacts 104, 106, 108, and 110 are closed. Contacts 104, when closed, serve to establish a hold-in circuit for maintaining energization of the solenoid 90 when the switch 7 8 is opened, such circuit including the secondary 114, contacts 104, contacts 92, solenoid 90, and switch 70 through contact 116. Contacts 106 serve to close a circuit between the line 82 and the line 80 through the motor field 74, contacts 108 and 110 serving to close a circuit through the motor starting winding 76, such circuit deriving its power from the line 80 through lead 118 and from the line 82 through lead 120.

When the motor starts, the sprocket 18 is driven slowly and drives the door toward an open or closed position. When the door reaches its closed position, it is stopped by an abutment, whereupon the friction clutch formed by plates occurs, relative rotation takes place between plates 20, 26 and 44, whereby the projections 48 ride from the raised surfaces 38 to the intervening plate surfaces 39. This actuates the lever 60 and actuates switch 70 to open the contacts 116 and close such switch through the other contact 122. When the switch 70 is thus opened with respect to contact 116, the solenoid 90 is de-energized, and the contacts 104, 106, 108, and 110 are opened, and contacts 102 are closed. When the switch 78 is again manually closed for a brief period, solenoid 88 is energized through a circuit including contacts 102 and contact 122 of switch 70. Thereupon solenoid switch contacts 92 are opened, and contacts 94, 96, 98, and 100 are closed.

Switch contacts 94 establish a hold-down circuit in the same manner as established previously by contacts 104. Contacts 96 close a circuit to the motor field 74, and contacts 98 and 100 complete a circuit to the motor starting winding, such connection being reversed from the connection established by contacts 108 and 110. Thus, the motor rotates in the opposite direction, causing the sprocket 18 to rotate in the opposite direction,

and 26 is caused to slip. As soon as slippage moving the door toward its other end position. When the door is stopped by suitable abutments or by obstruction, slippage again occurs on the clutch plates 20 and 26, causing relative rotation between plates 26 and 44. Such action causes the projections 48 to ride up the cam surfaces 42 or 40 to the raised arcuate surfaces 38, shifting the switch 70 back to the position shown in Figure 7.

It will be appreciated that the door may be stopped regardless of direction at any point along its path of travel if sufficient resistance to its movement is applied to cause the clutch plates 20 and 26 to slip. Thus, should a door strike an object which might be damaged by continued operation'of the closing or opening movement, the door will instantly stop, and upon the next operation of the manual switch 78, such door will move in the reverse direction away from the obstruction. It will be appreciated that the spring 36 may have its tension adjusted, so that the clutch may slip upon the slightest overload or upon heavy overload to suit conditions. It will further appear that the earns 40 or 42 are of relatively short arcuate length, so that when the motor current is cut off, the over-ride will assure suficient additional relative rotational movement between the plates 26 and 44 as to move the projections 48 e'ther from the surfaces 39 to the raised surfaces 38, or vice versa, and sufficient to actuate switch 70. It can be readily seen that the need for a sprocket and chain or positive drive is eliminated, so that while a sprocket is shown, yet an economical belt drive can be used, and that protection against motor overload is provided, since any overload instantly acts to cut the motor off.

While a single embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In a power actuator for an overhead door or the like, a reversible electric motor, a reduction gear driven thereby having an output shaft, a drive member freely rotatable on said shaft, a friction clutch having a predetermined slipping torque for coupling said drive member to said shaft, whereby said shaft may rotate relative to said drive member upon said drive member resisting rotation in excess of said torque, and means responsive to relative rotation in either direction between said drive member and shaft caused by exceeding said torque for de-energizing said motor.

2. In a power actuator for an overhead door or the like, a reversible electric motor, a reduction gear driven thereby having an output shaft, a drive member freely rotatable on said shaft, a friction clutch having a predetermined slipping torque for coupling said drive member to said shaft for rotation together until said torque is exceeded, a circuit for energizing said motor for rotation in one direction, a circuit for energizing said motor for opposite rotation, and means responsive to the slipping of said clutch and relative rotation between said shaft and member for de-energizing one or the other of said circuits and preparing the remaining circuit for energization.

3. In a power actuator for an overhead door or the like, a reversible motor, a reduction gear driven thereby, and having an output shaft, a drive wheel freely mounted on said shaft, a friction driving face thereon, a disk secured to said shaft, and having a friction face engaging said driving face under a predetermined pressure whereby slippage is prevented below a predetermined torque, said disk having on its opposite face alternate arcuate axially staggered surfaces, said alternate surfaces lying in spaced planes, a follower disk freely rotatable and axially movable on said shaft and having engaging means adapted to ride on either one set of said alternate arcuate surfaces or the other, means for constraining said follower disk to rotate with said drive wheel, and means responsive to axial movement of said follower disk for stopping said motor.

4. In a power actuator for an overhead door or the like, a reversible motor, a reduction gear driven thereby, and having an output shaft, a drive wheel freely mounted on said shaft, a friction driving face thereon, a disk secured to said shaft, and having a friction face engaging said driving face, means for engaging said faces under a predetermined pressure whereby slippage occurs only after a predetermined torque is exceeded, said disk having on its opposite face alternate arcuate axially staggered surfaces, said alternate surfaces lying in spaced planes, a follower disk freely rotatable and axially movable on said shaft and having engaging means adapted to ride on either one set of said alternate arcuate surfaces or the other, means for constraining said follower disk to rotate with said drive wheel, said engaging means being adapted to move said follower disk axially from one position to the other upon relative rotation between said friction disk and wheel when said predetermined torque is exceeded, and means responsive to axial movement of said follower disk for stopping said motor.

5. In a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby, and having an output shaft, a drive wheei freely mounted on said shaft, a friction driving face thereon, a disk secured to said shaft, and having a friction face engaging said driving face, means for engaging said faces under a predetermined pressure whereby slippage occurs only after a predetermined torque is exceeded, said disk having on its opposite face alternate arcuate axially staggered surfaces, said alternate surfaces lying in spaced planes, a follower disk freely rotatable and axially movable on said shaft and having engaging means adapted to ride on either one set of said alternate arcuate surfaces or the other, means for constraining said follower disk to rotate with said drive wheel, said engaging means being adapted to move said follower disk axially from one position to the other upon relative rotation between said friction disk and wheel when said predetermined torque is exceeded, a lever engaging said follower disk and adapted to be rocked by axial movement thereof from one position to the other, and a switch actuated by said lever adapted to de-energize said motor upon axial movement of the follower disk.

6. In a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby, and having an output shaft, a drive wheel freely mounted on said shaft, a friction driving face thereon, a disk secured to said shaft, and having a friction face engaging said driving face, means for engaging said faces under a predetermined pressure whereby slippage occurs only after a predetermined torque is exceeded, said disk having on its opposite face alternate arcuate axially staggered sur faces, said alternate surfaces lying in spaced planes, a follower disk freely rotatable and axially movable on said shaft and having engaging means adapted to ride on either one set of said alternate arcuate surfaces or the other, means for constraining said follower disk to rotate with said drive wheel, said engaging means being adapted to move said follower disk axially from one position to the other upon relative rotation between said friction disk and wheel when said predetermined torque is exceeded, a lever engaging said follower disk and adapted to be rocked by axial movement thereof from one position to the other, a circuit for energizing said motor for rotation in one direction, a circuit for energizing said motor for opposite rotation, a switch actuated by said lever and adapted to open one or the other of said circuits and prepare the remaining circuit for energization.

7. In a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby and having an output shaft, a drive wheel freely rotatably mounted on said shaft having a friction driving face, a friction disk secured to said shaft having a face in engagement with said driving face, means maintaining axial pressure between said faces to establish a predetermined maximum driving torque which, when exceeded, results in slippage, said friction disk having on its opposite face a plurality of alternate arcuate surfaces axially staggered with adjacent arcuate surfaces connected by axial camming surfaces, said surfaces comprising two sets lying in axially spaced planes, a follower disk axially movable on said t having following means adapted to engage one at a time one set or the other of said arcuate faces, said disk being keyed for rotation with said drive wheel whereby upon friction slippage between said wheel and friction disk, said following means is cammed from one set of arcuate surfaces to the other and moved axially, means responsive to axial movement of said disk for stopping said motor.

8. in a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby and having an output shaft, a drive wheel freely rotatably mounted on said shaft having a friction driving face, a friction disk secured to said shaft having a face in engagement with said driving face, means maintaining axial pressure between said faces to establish a predetermined driving torque, said friction disk having on its opposite face a plurality of alternate arcuate surfaces axially staggered with adjacent arcuate surfaces connected by axial camming surfaces, said surfaces comprising two sets lying in axially spaced planes, a follower disk axially movable on said shaft having following means adapted to engage one at a time one set or the other of said arcuate faces, said disk being keyed for rotation with said drive wheel whereby upon friction slippage between said wheel and friction disk, said following means is cammed from one set of arcuate surfaces to the other and moved axially, a lever engaging said disk and adapted to be rocked by axial movement thereof, and a switch actuated by said lever adapted to de-energize said motor upon axial movement of the disk.

9. in a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby and having an output shaft, a drive wheel freely rotatably mounted on said shaft having a friction driving face, a friction disk secured to said shaft having a face in engagement with said driving face, means maintaining axial pressure between said faces to establish a predetermined driving torque, said friction disk having on its opposite face a plurality of alternate arcuate surfaces axially staggered with adjacent arcuate surfaces connected by axial camrnin surfaces, said surfaces comprising two sets lying in axially spaced planes, a follower disk axially movable on said shaft having following means adapted to engage one at a time one set or the other of said arcuate faces, said disk being keyed for rotation with said drive wheel whereby upon friction slippage between said wheel and friction disk, said following means is cammed from one et of arcuate surfaces to the other and moved axially, a lever engaging said disk and adapted to be rocked by axial movement thereof, a circuit for energizing said motor for rotation in one direction, a circuit for energizing said motor for opposite rotation, a switch actuated by said lever and adapted to open one or the other of said circuits and prepare the remaining circuit for energization.

10. In a power actuator for an overhead door, a reversible motor, a reduction gear driven thereby and having an output shaft, a drive wheel freely rotatably mounted on said shaft having a friction driving face, a friction disk secured to said shaft having a face in engagement with said driving face, means maintaining axial pressure between said faces to establish a predetermined driving torque, said friction disk having on its opposite face a plurality of alternate arcuate surfaces axially staggered with adjacent arcuate surfaces connected by axial camming surfaces, said surfaces comprising two sets lying in axially spaced ergizing said motor for opposite rotation,

planes, a follower disk axially movable on said shaft having following means adapted to engage one at a time one set or the other of said arcuate faces, said disk being keyed for rotation with said drive wheel whereby upon friction slippage between said wheel and friction disk, said following means is carnmed from one set of arcuate surfaces to the other and moved axially, a circuit for energizing said motor for rotation in one direction, a circuit for enand means responsive to axial movement of said disk for de-energizing one or the other of said circuits and preparing the remaining circuit for subsequent energization.

References Cited in the file of this patent UNITED STATES PATENTS Chandler July 31, 1928 Hawkins Jan. 25, 1938 Opalek Feb. 22, 1944 Eddison Sept. 13, 1949 Slack Jan. 2, 1951 Hopkins et a1 Dec. 25, 1951 Michie Aug. 4, 1953 Moody et a1 Sept. 15, 1953 Hahn Mar. 16, 1954

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