US 3825809 A
An automatic power operator for garage doors having adjustable limit stops including a short screw shaft driven by the operator motor and a pair of traveler nuts on the screw shaft and individually adjustable in linear position to establish up and down limits of travel. The travelers nuts operate in connection with up and down limit switches to shut off power to the drive motor after the predetermined limit of travel has been reached. A "memory" device in the form of a pivotal lever is disposed adjacent the screw shaft and the down limit switch to hold the down limit switch in the open circuit condition until the door is nearly fully opened such that a second actuation of the device following initiation of movement in the upward direction simply causes the operator motor to stop. By this feature any of an infinite number of partially opened door positions can be readily accomplished by the user.
Claims available in
Description (OCR text may contain errors)
United States-Patent 191 Gatland et al. 1 f A [5 1 GARAGE DOOR-POWER OPERATOR HAVING PARTIALOPEN CAPABILITY  Inventors: Geoffrey W. Gatland, Walled Lake,
Mich.;vKenneth L. Robitallle, Windsor,f0ntario, Canada 1  Assignee: Vemco Products, Inc., Detroit,
221 Filed: July 23,1973
 Appl. No.: 382,029
. US. Cl 318/282, 318/286, 200/47 July 23,1974
' Primary ExaminerB. Dobeck  ABSTRACT An automatic power operator for garage doors having adjustable limit stops including a short screw shaft driven by the operator motor and a pair of traveler nuts on the screw shaft and individually adjustable in linear position to establish up and down limits of travel. The travelers nuts operate in connection with up and down limit switches to shut off power to the drive motor after the predetermined limit of travel has been reached. A memory devicein the form of a pivotal lever is disposed adjacent the screw shaft and the down limit switch to hold the down limit switch in the open circuit condition until the door is nearly fully opened such that a second actuation of the device following initiation of movement in the upward direction simply causes the operator motor to stop. By this feature any of an infinite number of partially opened door positions'can be readily accomplished by the user.
7 Claims, Drawing Figures I l l l 1 la JUL u *sg-i'iiT-IL' I "w/n/n/n/r/mr//////// cARAoE ooR POWER OPERATOR HAVING PARTIAL OPEN CAPABILITY INTRODUCTION This invention relates to power driven apparatus for opening and closing garage doors and the like and more particularly to a power'operator which may be selec- I tively stopped when the door is in a partially open position. t
' BACKGROUND OF THE INVENTION- A power operator for garage doors and the like typically'comprises a motive power source in the form of a .reversible electric motor, means for connecting the motor to the garage door to cause the doorto travel be-;
or equivalent and a traveling nut limit switch arrangement having individually adjustable up and downtravel limits generally of the type set forth in the Miller U.S. Pat. No. 2,951,920.
BRIEF DESCRIPTION OF THE INVENTION 1 In accordance with the present invention, a power operator for garage doors and the like is provided wherein the door is caused to be displacedbetween up and down limits of travel .by successive actuations of a motive power source, such as a reversible electric mtor, wherein the door maybe selectively stopped in substantially any partially opened position between fully closed and fully opened positions simply by causing a second operation'of the input device as the door travels toward the opened position. In generahthis is this, limits'witches and adjustable switch tripping devices are typically'e'mployed. A suitable mechanism for establishing individually adjustable up and down limits of door displacement is disclosed in U.S. Pat. No.
2 ,95l,920' to Harold L. Miller entitled Rotary Limit Switch. The Miller patent discloses anappar atus .com-
prising a 'rotatably 'niounted" screw shaft of several inches in length and driven by the operator motor, a pair of limit switches mounted adjacent the screwshaft,
and a pairof switch-actuating traveling nuts threaded on the shaft but held against rotation so as to move linearly along the shaft as theshaft rotates. One ofthe' nuts operates in conjunction with one switch to open circuit the motor at'the up limit of travel and the other nut operates in conjunction with another limit switch to open circuit the motor at the down limit of travel.
It is also necessary in a power operator of the type described above toprovide means for automatically ef' fectinga reversal of the energizing circuit through the motor at each of the limits of travel so that upon reaching the up limit, for example, the down energizing cirit is common to employ a ratchet relayf which responds to successive operation of theinput device, ei-
ther push button or radio transmitter, to toggle a motor y direction switch back and forth between positions which establish the up and down energizing circuits respectively. In an operator employing such a circuit reversing device, it is apparent thatsuccessive actuations of the input device cause areversal in the dirction of door displacement irrespective of the limits of travel.
Accordingly, under normal operating conditions, operation of the input device while the door is traveling up wardly causes the door. to reverse immediately and move in the downward direction,Correspondingly, a second operation of the input device during motion of the door in the downward-direction causes an immediate reversal and a return of the door to the up position.
accomplished by an apparatus including individual up and down limit switches and individually adjustable "actuators for those limit switches for opening the up and down energizingcircuits atpreselected limits of travel, a toggling mechanism, such as a ratchet relay, responsive to successive operations of an input device to alternately establish the up and down energizing circuits through a motive power source and, in addition, an ac tuating member having a memory feature responsive to motion of the switch actuators to hold the down limit switch in a disabled or open circuit condition during travel of the door from the fully closed position toward the fully opened position. By virtue of the actuator device and the memory feature thereof, successive actuation ofthe input device do not cause a reversal of the door during the opening displacement, but rather simply result in alternatev stoppage of the door and resumption of the upward-travel. The door may, therefore, be selectively stopped many of an infinite number of partially opened positions, the operator being such as to draw no power while the door is inthe partially opened position and the operator mechanism itself being such as to substantially lock the door against further opening when in the partially opened'position. The
reversing mechanism, however, operates in the normal fashion during'tr'avel of the doorin the downward dicuit is established and vice versa. To accomplish this, t
rection,.thus, to facilitate the incorporationof such safety devices as obstacle detectors, overload detectors", and the like which automatically reverse the direction of the door travel should the door encounter acar or person when moving toward the closed position.
The various features and advantages of thesubject invention will be best understood from a reading of the following specification which sets forth in detail an il- 'Iustrative embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 6 is a schematic circuit diagram illustrating the electrical interconnections between the power source, electrical voltage supply, input device, limit switches,
3 and reversing mechanisms used in connection with the device of FIGS. 2 through 5.
DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT includes a rigid rail 16. defining the longitudinal pathof displacement for a traveler 18 which is pivotally connected to the door 12 by means of an arm 20. The garage door operator may, for example, include an elongated screw shaft which is suitably journaled within the rail 16 and meshing with a trapped nutto produce longitudinal displacement of the traveler 18 along the rail 16 in a direction which is determined by the direction of rotation of motor 35. The details of the drive assembly and the mechanical devices which secure the drive assembly tothe door 12 are not a partof the present invention and will not be discussed in great detail.
In accordance with'the invention, the limits of travel of the door 12 relative to the structure 10 may be individually and accurately preset by structure hereinafter described. Moreover, the powerdrive apparatus is such as to permit the door 12 to be selectively stopped inthe partially opened position'showri by solid lines in FIG. 1 during the upward movement of the doorl The initiation of the upward travel'and the stoppage of the upward travel in the selected part-openposition are ef-v fected by'successive operation of an input device hereinafter described so as to provide an opening at the bottom of the door for such purposes as domestic anima access, ventilation, and light.
Looking now to FIGS. 2 through 5, a portion of the tion and, thus, are caused to move synchronously and linearly along the screw shaft 28 as it rotates. Accordingly, the relative axial spacing between the nuts 34 and 36 as well as the absolute spacing of the nuts relative to the shaft 28 is effective to determine the respective up and down limits of travel as well as the overall degree of travel which will be permitted the door 12 during operation of the power drive.
The nuts 34 and 36 perform the limit stop function in conjunction with limit switches and 42, respectively, which are mounted on the support bracket 22, as best shown in FIGS. 3 and 4. The upward limit of travel is reached when the nut 36 engages the actuator of the limit switch 40 so as to open circuit that switch. Similarly, the downward limit of travel is reached when the nut 34 causes depression of the actuator of switch 42 by means of an actuator lever 46. A third limit switch 44 is also mounted on the support bracket 22 for purposes to be described.
The actuator lever 46 comprises a tab 40 at the fulcrum point and oppositely extending fingers. The lever is pivotally secured to the support bracket 22 by means of a screw 50, a nut 52, and a friction spring 54. The combination of elements 50, 52, and 54 establishes a relatively high friction condition in the pivot such that the lever arm 46 tends to remain in any angular position in which it is placed until positively driven to another orientation. By this arrangement the effect of memory is built into the operation of switch 42 such that when the lever arm 46 is driven in the clockwise direction by engagement with nut 34, thus, to depress the actuator of switch 42, its tends to remain in that position, continuously depressing the actuator of switch 42, until nut 36 engages the right depending arm of lever 46 and drives it back in the counterclockwise direction. The resetting of switch 42 by engagement of structure and electrical circuit components within the housing 14 to carry out the part openfeature previously described are shown. Thisapparatus includes'a support bracket 22 having axially spaced and laterally projecting flanges 24 and 26 to support a screw shaft 28. The shaft 28 is on the order of six inches in length in the typical case. Suitable journal blocks 30 may be provided to accommodate rotation of the screw shaft 28, the drive to produce such rotation including the bidirectional motor 35, the pulley 32, and a belt (not shown). Accordingly, the screw shaft 28 rotates at a speed and in a direction which isdetermined by the primary drive motor 35 during movement of door 12.
Threadedly engaging the screw shaft 28 are switch actuating nuts 34 and 36 of which the position of the nut 34 on the shaft 28 establishes the limit of travel of the door 12 in the downward direction and the position of the nut-36 establishes the limit of travel in the upward direction as hereinafter described. The peripheral surfaces of the nuts 34 and 36 are notched to provide engagement with a spring biased latch plate 38 which is pivotally disposed on the support bracket 22 and resiliently secured by means of a spring 39. When the upper edge of the latch plate 38 engages the notches in the nuts 34 and 36, the nuts are restrained against rotanut 36 with the righthand finger of lever 46 occurs when the door- 12 is about three-quarters open. Accordingly, the lever arm 46, by virtue of the frictional pivot arrangement, has an ability to remember the condition of switch 42 established by the nuts 34 and 36 reaching one limit of travel and to maintain that condition until the nuts 34 and 36 reach nearly the opposite limit of travel.
The overall .function of the apparatus and the electrical circuit components of FIGS. 2 through 5 may be best understood by reference to the circuit diagram of FIG. 6. In that circuit'diagram it can be seen that input terminals 56 and 58 are adapted to be connected across a conventional l20-volt, 60-cycle power supply to energize the bidirectional two-phase motor 35. The terminals 56,aand 58 are connected across the primary winding 60 of a small conventional transformer. The secondary winding 62 of the transformer is connected in series with the coil' of a bistable ratchet relay 64 and an input device in the form of a conventional springbiased push button 68. Depressing the push button 68 causes a momentary surge of current through the relay coil 64, thus, toggling the two-position armature 66 of the ratchet relay between terminals 70 and 72. When the armature 66 engages terminal 70, current is directed from power supply terminal 58 through the switch armature 66, the down limit switch 42, and the conductor 76 to the motor 35. A second input phase is supplied to the motor 35 by way of capacitor 74 and conductor 78, thus, to produce rotation of motor 35 in 64 causes armature .66 to toggle into engagement with terminal 72 which completes an energizing circuit through the up limit switch 40 to the motor 35. One
' phase is supplied directly tothe motor 35 by way of conductor 38 and a 90 phase shifted waveform is supplied-through the capacitor 74 and the conductor76. Accordingly, the direction of motor rotation is reversed whenever the armature 66v movesfrom terminal 70 to terminal 72 and'vice versa. The actual energization of the motor 35 is, however, entirelydepe'ndent upon the openedfand closed conditions of the limit switches 40- and 42, the bistable ratchet relay arrangement 64, 66
\ being effective only to establish or enable anenergizing circuit in either'the up or down direction.
, 6 l I travel. Obviously, this mechanism must be disarmed justbefore the door 12 reaches the fully closed position to prevent the automatic reversal and continuous cyv cling of the door 12 as it reaches the closed position.
' The limit switches 40 and 42 are of the normally I .closed type and may be purchased from a variety of sources including the Unirnax Switch Division of Maxson'Electronics Corporation, Wallingford, Connecticut 06492. Switches sold under Unirnax No. BTMT 14-4 have been found satisfactory. The switches are normally closed except when the actuatorsthereof are depressed, i.e., moved toward theiswitch-body by the associated switchactuating nuts 34, 36. The ratchet relay comprising coil 64, armature 66, and suitable provisions for terminals 70'and72isalso'a commercially available component and a suitable device is made by Ingrahm Industries, a-division of McGraw' Edison in Bristol, Connecticut 06010, their model No. C6909A.
, OPER TION Describing now-a typical operation of the subject device, it is assumed that the door 12 is found in the fully opened position represented in FIG. 1 by the reference character 12b .suchthat nut 36 is driven to the full switch 40. Armature 66 is in contact with terminal 72.
h In the fully opened condition, however, thelimit switch 40 is open circuited such that no circuit may be completed through the motor 35 by way of terminal 72. The displacement of nut 36=to the righthandlimit of FIGJ4 alsocauses counterclockwise rotation of the lever arm 46, thus, to permit the down limit switch 42 to close establishing the necessary circuit through motor 35 to produce downward rotation upon actuation of the input switch 68. Assuming now the switch 68 is momentarily depressed, the momentary surge of current through relay coil 64 causes the armature 66 to move from terminal 72 to terminal 70 completing a circuit through the now closed switch 42 to drive the motor 35 in the, downward direction. Displacement of the door 12 continues until the nut 34 moves to the full lefthand position shown in FIG. 4 tipping the lever arm 46 in the clockwise direction and open circuiting switch 42.
It can be seen that displacement of nut 34 to the lefthand limit of travel also causes engagement with the acrighthand positionto depress the actuator of limit ployed.
The subject invention is, thus, fully compatible with such automatic reversing mechanisms.
Assuming one now wishes to open the'door 12, the button 68 is again depressed to produce a current surge through the coil 64 of the ratchet relay. Armature 66 moves from terminal 70 toterminal 72 to complete a circuit through the now closed switch 40 to drive the motor in suchh direction asto open the door 12. The nuts 34 and 36 move to the right as seen in FIG. 4, but the memory feature of the lever arm 14 issuch that it remains in position, holding the limit switch '42 open. Accordingly, the downqenergizing circuit is not established while the door travels upwardly. Therefore, a second subsequent depression of push button 68 to toggle the armature'66 back to terminal 70 results in the stoppage of the motor 35 since. the power supply on input terminal 58 is now directed to an open switch 42. Accordingly, the door l2-may be stopped in any partly opened position, the limit. of such stoppage feature being reached only when the 'nut .36 reaches therighthand depending finger of lever arm 46, as shown in FIG/4, to move it back in the counterclockwise direction to close switch 42.
In summary it can be seen that the part open feature is accomplished only when'the door is'displacingfrom the fully closed position to the fully opened position, the lever arm 46 remembers the closed position and the open circuited condition of switch 42 and the nut 36 has not yet reached the righthand position shown by phantom lines in FIG, 4. T
It is to be understood that the invention has been described with reference to an illustrative embodiment and that various modifications and additions may be madewln addition, it is to be recognized that although the push button 68 has been illustrated as an input device, other suitable input devices including both manual and radio-operated arrangements may be em- The'embodiments of the inventionin which an exclusiveproperty or privilege is claimed are defined as followsz' 1. In a power door operatorof the type including a motive power source and a reversing means for alternately establishing up and down'energizing circuits through the source causing the load to be driven inopposite directions upon successive actu'ations' thereof, the improvements comprising: a screw shaft driven by the source, first and second normally spaced-apart nuts threadedly engaging the shaft and driven linearly therealong according to' the direction of shaft rotation, means for permitting individual adjustment of the relative-linear positions of the first and second nuts on the shaft to define respective up and down limits of travel, and memory means including a member disposed adjacent the shaft and freely and cyclically displaceable by the nuts between first and second positions each time the nuts reach their respective limits of travel and to remain in such positions until the nuts approach the opposite limit of travel, said memory means being operative to disable the down energizing circuit when in one of said positions whereby actuation of the reversing circuit during upward travel of the load causes'the source I to be deenergized.
2. Apparatusas defined in claim 1 further including a support means for carrying the screw shaft, said memory means member including a lever pivotally mounted on the support means and having first and second fingers extending toward opposite ends of said screw shaft be pivoted between said first and second positions by the first. and second nuts, respectively, each time said nuts approach respective limits of travel.
3. Apparatus as defined in-claim 2 wherein said memory means further include a relatively high-friction pivotal mounting for said lever whereby said lever tends to remain in each of the two positions of pivotal orientation thereof until positively displaced by one of said nuts toward the other of said positions.
4. Apparatus as defined in claim 2 wherein said reversing circuit further comprises up and down limit switches disposed on said support means adjacent opposite ends of said screw shaft, the up limit switch being actuated directly by one of said nuts and the down limit switch being actuated by the other of said nuts through said actuator lever.
5. Apparatus as defined in claim 4 including input means comprising an input switch for controlling operation of said power source, and relay switch means responsive to operation of the input switch to alternately connect an electrical power source to the motive power means through the up and down limit switches, respectively.
6. In a power operator for garage doors and the like:
a motive power source capable of driving a garage door down limits; a support bracket; a first switch carried by the bracket for controlling a first circuit to the source for driving the shaft in one direction; a second switch carried by the bracket for controlling a second circuit to the source for driving the shaft in the opposite direction; a bistable relay switch for alternately connecting a source of electrical energy to the first and second switches, respectively; and an actuator lever freely pivotally mounted on the bracket adjacent the screw shaft and the first switch and cooperating with the first and second nuts to pivot with each cycle of door operation between a first position corresponding with the down limit and a second position corresponding with the up limit, the lever being operatively engageable with the first switch for holding the switch in the open circuit condition while said lever is in the first position whereby the relay switch operates only to energize the power source in the up direction as long as the lever is in the first position.
7. In a power door operator including a reversible electric motor and means for establishing first and second circuits through the motor for causing rotation of the motor in opposite directions: first and second limit switches and first and second independently adjustable traveling members for operatively engaging respective limit switches to establishing the opposite displacement limits for said operator, and memory means operated by said traveling members during each cycle thereof to maintain one of the limit switches in an open circuit condition'after being placed in such condition by a first traveling member substantially reaching one of said limits and until the other traveling member substantially reaches the other of said limits.