US2476111A - Mechanism for automatic stopping and reversal of electromechanically operated doors - Google Patents

Description

' July i2, 1949. c. OPALEK 2,47611 MECHANISM FOR AUTOMATIC STOPPING ANDl REVERSAL OF ELECTRGMECHANICALLY OPERATED DOORS Filed July '7. 1945 4 Sheets-Sheet 1 July 12, 1949. c. OPALEK 2,476,11

MECHANISM FOR AUTOMATIC STOPPING AND REVERSAL OF ELECTROMECHANICALLY OPERATED DOORS 4 sheets-sheet 2 Filed July 7, 1945 July 12, 1949. c. OPALEK A 2,475,111

MECHANISM FOR AUTOMATIC STOPPING AND REVERSAL OF' ELECTROMECHANICALLY OPERATED DOORS Filed July 7, 1945 4 Sheets-Sheet 3 lNVENTOR Chf/:fa Es @PAM-K @Y BLZ@ MM ATTORNEY July 12, N949. c. OPALEK MECHANISM FOR AUTOMATIC STOPPING AND REVERSAL OF ELECTROMECHANICALLY OPERATED DOORS 4 Sheets-Sheet 4 Filed July 7, 1945 @www awww QW M O CLOSE INVENTOR CHARLES OPALE/6 ATTORNEY Patented July 12, 1949 TED STATES OFFICE 12 Claims. 1 This invention is related'toiand constitutes lan addition to mys invention disclosed' and'patented IinLettersy Patent Nos. 2,3l2;597'v and '25366,948.

In those prior patentsaaredisclosed a` system and mechanism for automatically leiiecting the I operation of doors, such as garage doors, under they control ofimanual-switches either within or outside the garage.

Thepurpose of-this invention is to vadd to such system-and mechanism safety means for avoidiingdamage or injury in case the doors encounter an obstruction during-theirmovement either toward closed. or .open position.

Preferablythe means of this invention will operate to reversethe power device-if an obstruction is ymet while a door is closingand thus cause thepartially closeddoor to return to open position. As a precautionary measure in case an obstruction ismet While-'a door isopening, it will ordinarilyY suiiice to disable the power device,.as, for example, to open vthe circuit'of an electric motor and avoid damagingthe motor.

The objects and'a'dvantages of the .invention 'will be understood from thefollowing description of the 'embodiment-,ofthe invention illustrated in the accompanying drawings, in which Figs. lis a diagram `of the electrical system.

Fig. 2 is an'elevation, partly in section,"of V the lowerpart'of a'door equipped with the contacts 3 forming; part ofthe system.

Fig. 3is anenlarged lfragmentary'section on line 3--3 of Fig.'2. Fig. 4 lis a 'bottom plan View 'with 'the door frame in section; showing the doors Open andthe "operating mechanism as'viewedby'one standingf in the doorway' andy looking up.

Fig. 5 isf-aviewsimilartoFigxl on' an enlarged 'scale and partially in setionfof the operating mechanism `shown 'for the right hand door'in fFigdfi.

Fig. y6 isan'elevation, partly'in'section, as in- `dicated onl the line 6-6' of'Fig.'5.

Fig. 7 is a sectional elevation'on the'- line "1--1 "ofFig, 5.

Fig. 8 is a View similartoFig. lof the'right 'hand door-andpart cfthe'leftlland door'an'd lthe operating-fmech-anism ltherefor;showing the fdoors closed.

Fig. 9 is ya detailin'sifdeelevation, indicate'd'by the line 9-9 in Fig. 6; ofthe 'reversingswitch--and its support withi the operating links in section.

Fig-10V is an'underside IView of the gearbox and 'cut-outswitchth'ereon and indicating the ipositionof the: parts 1v'when 4-th'e switch isv open.

ingl the position 'ofthe-parts when the arm has moved substantially `10" -from its extreme open position, allowing theswitch to close.

The invention is shown-as applied Ato swinging doors, but `itfwil-lbe understood that it is equally applicable to 4so-ca-llecloverhead doors, that is, doors that articulate sandy slide up and down to 'openand close.

Primarily ythe illustrated embodiment is -designed to prevent injury to one caught in between the two doors -as their proximate edges approach .each @then-and in theiorrn shownfthe doors are equipped at or-nearftheiry free edges with yieldable rcontacts that cooperate With fixed contacts on the door to close van electric circuit and` thereby operate mechanism-that|will reverse the motor. Preferably the yieldable contacts, such as springs, are covered with a-protective' fabric such Aas leather or rubber.

'-5l having worms' andz'f that mesh with and drive Worm gears 8 and i),"respectively, in their'respe'ctive-gear boxesfliand II. Toggle linkage I2 vconnects the shaftof'worm Wheel' to ydoor2and similar linkage I3"con`nects'the shaft of Worm wheel 9 with door I; "The motor and the asso- `ciated 'mechanism just ldescribed is' secured on the underside of thetop of the 'door frame by 4a plate I4 on each end 'attached tothe frame by vbosses' or other suitable' means.

Areversible switchl'i ofthe mercury type is 'pivotally mounted'inthe depending arms of an 'inverted U-shape bracketA I6 secured to the same lplate I4 as is the motor 3 and disposedibetween the motor a'nd'tliereduction gearing-4y Withits axis at right `angles'to the worm'shaft 5. The

switch I5 is a vquadrupleswitch with'two pairs iolof contact elementsfa, and I5b closed with the switch in one position andtheother two pairs For reversing the switch it has a lever arm 'I1 on 'site"directions andactuated by means to be de- Looselymountedonthe shaft 8a of the worm lwheel immediately above the link arm "I2is a Acarri lever IS-haVingS'a'n arcuate slot I'Ba therein into which extends-1aV pin- 2'0 on the "arin I2. The

ifoam lever i9 isconnecteid'to-apin-on the lower having a slot into which the pin engages so as to permit of the snap over of the switch by the spring I8. The length of the arcuate slot I9a and the disposition of the cam lever I9 relative to the pin 28 are such that the link 2 I reverses the switch near the end of movement of the arm I2 in both opening and closing the door.

A magnet 22, which I term a reopen magnet, is also secured on the plate I4 alongside the motor 3 and opposite the switch I5. A pivoted armature 23 of the magnet 22 is attached by link 24 to ar pin on the other end of the switch arm I1, the link having a slot into which the pin engages so as to permit reciprocation of the switch under the inuence of link 2|, without interference of link 24, under circumstances that will be later explained. A relay box 25 may be disposed adjacent the motor, as shown.

The reopen magnet 22 is energized when the doors meet an obstruction on their way shut, and the magnet then operates to reverse the switch and thus reverse the motor and open the doors. This can occur, of course, only when the arm I2 and hence the pin 28 has moved sufficiently from the extreme open position to allow the cam lever I9 to turn as much as the reversal of the switch requires. Consequently I provide a cut-out switch 25 also under the control of the pin 20 which opens and closes contacts in the control circuit for the reopen magnet, as will appear from the wiring diagram later to be explained. The switch 25 is pivoted on an adjustable plate 2E on the gear box Ill, immediately above the cam lever I9, and the pin 20 extends up through the slot 19a far enough to engage the end of the switch, as shown in Figs. and 6.

The control of this switch by the arm I2 is especially shown in Figs. and 11, from which it will be seen that the pin 20 engages the member 25 and opens the switch in the extreme open position of the door, substantially within the angular distance of 10 from the open line position of the arm I2. A coil spring 26 urges the member 25 in the direction to close the switch.

Both doors have a metallic contact strip 2'I, the two strips being electrically connected in parallel into one side of a reopen relay circuit which functions in a manner to be described. Both doors also have secured over the lower portion of their free edges an angle plate 28' which covers the edge and overlaps the inner face of the door, the two plates being electrically connected in parallel to the common return lead of the reopenl relay and of a stop relay, as will appear. Also both doors have on their outer face a contact plate 29, adapted to make contact with the angle plate 28 when, for example, engaged by a relatively stationary body as the door opens, but normally held out of contact by springs 30, as particularly shown in Fig. 3. The two plates 2-9 are connected in parallel to one side of the stop relay.

Spring contact members 3| and 32 are vertically disposed on each door opposite and extending the full height of the plate 28 but insulated therefrom and normally out of contact therewith but positioned to be pressed into contact with the plate 28 when either spring engages a relatively stationary bodyas the door is closing. The two spring contacts are connected to the contact strip Z'I, and they are protected by a leather or rubber covering 33.

The safety features of the system to which this invention relates are engrafted upon the door operating system which is shown in the diagram of Fig. 1 and in the main is the same as that shown and described in my said prior patents. It will, therefore, not be necessary to explain in detail that much of the system as is common to the disclosure of my prior patents.

The master control relay 34 is energized from the secondary of transformer 35 when either one of the button contacts 36a, 36h and 36o is closed, through lead 31, normally closed armature contact 38 of the stop relay 38, lead 40, secondary winding of the transformer, lead 4I, winding of relay 34 and lead 42 back to the other side of the button contact.

This energizing of relay 3'4 attracts its armature 34a and thus closes contacts with normally open contact members 43a and 44o in circuit with the windings of motor control solenoids 43 and 44, respectively, through reciprocal cut-out switches 43h and 44h arranged, as shown, so that each solenoid when energized opens the circuit for the other solenoid. Thus the energization of relay 34 sets up the circuit for one or the other of the solenoids 43 and 44 depending upon the position of the switch I5. However, the circuit for the motor control solenoids 43 and 44 is short circuited at po-ints X and Y as long as the button contact is held closed.

The solenoid 43 acts to energize the motor 3 in a direction to close the doors, and the solenoid 44 acts to energize the motor in a direction to open the doors. Switch element I5b is in circuit with solenoid 43, and switch element' I5d is in circuit with solenoid 44. Therefore, when the switch I5 is in the position shown in Fig. 1 and the armature 34a is up, the circuit of the closing solenoid is closed from the transformer through wire 4I, winding of relay 34, armature 34a, movable contact 43a, wire 45, contact 44h, winding of solenoid 43, wire 46, switch element |527, common return 41 to point Y, and thence to armature 38 and wire 4i! back to the transformer.

With the switch I5 reversed and the armature 34a up, the circuit of the opening solenoid 44 is closed from point X and armature 34a back to point Y through movable contact 44a, wire 48, contact 43h, winding of solenoid 44, wire 49, switch element I5d and common return 4'I.

Each solenoid 43 and 44 controls three armature operated contacts which determine the direction in which the starting coil 3a of motor 3 is connected across the supply line 50 and also effect the connection of the running coil 3b across the line. Also the closing solenoid cooperates in control of the energization of the reopen magnet 22.

The solenoid 43 actuates three contact armatures 43o, 43d and 43e, and solenoid 44 actuates three contact armatures 44c, 44d and 44e. The iixed contacts for armatures 43e and 44e are both connected with the same side of the line, but the fixed contacts of the other two armatures of the two solenoids are respectively connected to opposite sides of the line. The leads of the running coil of the motor are connected, one to one side of the line and the other to the armatures 43e and 44e, the fixed contacts of which are connected to the other side of the line. One lead of the starting coil is connected to armatures 43d and 44d, and the other lead is connected to armatures 43e and 44o. Therefore it is evident that the switching from one solenoid to the other reverses the starting coil but merely continues the energization of the running coil. Hence the direction of operation of the motor depends upon whichsolenoid is energized and therefore uponthe` position of the switch.

disclosedin my'prior patents, this system also employs a fourth relay 5I which I term the reopen relay. This relay controls l:four'contact armatures, the contacts of three of which are normally open and the fourth of which isI normally closed,v and this relay is energized when a spring contact 3l or 32 is causedto'engage plate 28- and the switch I5 is in closing position as shown in Fig. 1, the circuit being closed asfollows: spring contact'3lf-or 32, wire 52, winding of relay 5l, contact 25, wire 53, 'element [5a of the switch, common return 41, contact 38, wire 40,'-transformer 35,1Wire 4|,backcontact 54 controlled by relay-34, wire 55andwire 56 back to the plate 28. This attracts armature 5I-a and closes a'short across points X -and'Y through `wire'5'i, armature contact Sla andnwire 58. The closing solenoid 43 is thus short circuited and the motor circuit is broken, while relay-Mds kept energized.

. At the same time relayf5l attracts armature-5H) and closes a holding circuit' for. itself4 as follows: from the transformer through wire 4I,y contact 54, wire 55, contact 5H), winding of relay 15|, switch 25, wire 53, switch'element 15a, return wire 41, contact 38 and'wire-40 back to theftransiormer. Hence relay 5ll stays energized until the switch'vis reversed, whether `or not'the spring contact z is longer held against plate 28.

Relay 5l valso attracts armatures 5lc and 5|d, the former closing a contact yof the reopen magnet- 22 and connecting one side of the magnet. to one side of the line through wire 59, contactw5flc and wire 60.

Armature 5 l d is the movable `part of .a normally closed contact in the-lead which provides the connection between one side of the motor starting coil 3a and .the armature contacts 43d.and 44d. Hence when the relay 5| is energized the circuit for the starting coil is broken at contact 55d.

The other side of the starting coil is connected to wire 6l which connects the side of the reopen magnet 22 opposite its connection to wire' 60, with a centrifugal contact 62 that breaks contact with the commutator when the motor is running and makes contact when the speed falls'Y below a certain value. The commutator is connectedby wire 63 to the armatures 43e and 44C.

Now it will vbe seen that when armature-*51e is attracted and the motor is at rest or below acertain speed so that centrifugal contact BZ'is closed, the reopen magnet is connectedacross the 'line through wire 59, contact 5Ic, wire (il),` coil 22', Wire 6I, contact 62 includingl the commutator, wire G3, armature 43C, afront contact Ifor-armature 43e and wirer 64 tothe other side of the'line.

The operation of the safety feature may-now be followed. It will be assumed that the switch-fis in thev closing position shown in Fig. 1 and that-a button has been pushed to'V close the door, thus setting up the circuit of closing'solenoid 431 and starting the motor in the direction to closethe door, as above explained. Then it willbe assumed that one Aof the doors `on its closing movement encounters an obstruction so as to deflecty one of the-safety spring contacts against plate 28.

'I'his energizes reopen' relay 5| through the circuit above traced. This closes the holding circuit through contact 5 lb and also short circuits points X and Y through closing of contactv 54a. -It also closes the connection through contact v5lc be v` tweennonef side-ot reopen magnet, 22:.and onezside of; the `Iline.

. .iT-he @short',circuitsbetween szpoints X and Y deenergizestheaclosing solenoids43'1and releases g; its'. contacts; thus.'stoppingthegmotor. .'lhe'cen-v tr-ifugal contact2f82f isz therefore closed `andw they circuit offthereopenmagnet isithus oloseduto the other.` sidecof. the nline. "The startingcoil. is not olosed;however;rbeingr open? at` contact 5 Id so long asf` relay? 5 Iz. isf energized.

The-.aboveassumes that theldoorl hadclosed far enoughlfrom its?fullyf-openfv position to effectzfa closing of switch 25, otherwise.'ofcoursefthevcircuitf-of; relayY 5I -wouldz not, haveY beenV completed.

The energizing of. magnet.' 22: cau-ses they arma-A ture 23 `torba attractedfwhch` reverses the switch anndithrowsz-itf over `to opening position. This setsriup'f the: circuiti for: :openings solenoidl 44,l the master-'relay 34 `beingrenergizedand holding contact 44a'. :inatheff circuit as long ,asf the `short circuit-between lpointsbX and iY-Hcontinues. The reversal` ofi the'fswitchifb-reaks' the circuit' 'of-relay 5I,ffbutilthe;release of: contactc-5lla `is timed: so aswto:l succeed: the closing of: theicircuit-v for solenoid y4.4, vand hence the energiza'tionof relay 34iar1d:` theconrtinuingwof contact 44a lin thercircuit is `not.interr1.-1pted.

V 'I3he .opening =of 'the'circuitforf the .reopenl relay.: 5 lrremovesthe 'short4v from" the circuit through thezopening solenoid'. 44. It Valso effects the closing ofthe startingcoil circuitat' contact 5'-d,witl`1 the result that' the :motors-promptlyl starts `inthe otherrfdirection and moves'` the' door-toward Iopen position away from 'the lobstruction.

The plate 29 and the stop-solenoid 39=oper ate toistopthe'motorlwhen an obstruction is encounteredduring2 the'fopenirigv movement ofy the door. lDurring'thatTmovernent the switch isrin the-.opposite positionfromvv that shown. Then -if plate29' isfmadeto contact plate 28 the circuit through-f solenoid 'i 39"r -is-=close'd as follows: from plate 29ffthrough wire 65,r coil 39,'wire B6, switch elementi e; return wire' 41, contactI 38, wire 45, the transformer coil,-fwire4 I, contact'54, wirei 55 and wirev'back to plate 28.

'This attra'ctsarmature38 and breaks the circuit' of 'relay' 3'4. Incidentally it breaks thev circuit f theY` stop' solenoid 3'9 alsofbutthe return of-` armatu-re'l38 is' timed so `thatrelay34 is surely deenergized.

fflt'is' obvious that 'changes may bey made `in the construction'f 'shown in] the drawings and above particularly described'fwithinf the principleA and sooner-of the invention.

The combination-of a door," a kreversible electricwmot'or l" and' ymeans connected therewith to operate ythef'door,-a -sourcev of'felectric power, a reversible-switchoperated by the said connected 60 means and arranged to connect the motor` selectively=in=reversedirections tothe source of power, an felectroemagn'e'ticpower device connected lto thereversible-"switch and operative when'energizedhto-zrnovef they switch' from itsV closing lposi- 65 tionV toits opening'positior'r a relay vin control of the i-power ldevice, andimeans for Venergizing the relay including normally' "open, contact elements carried bythesdoorfand adapted to `be closed-by engagernent:with al relatively stationary body.

f2. Ther-combination vof a1 door, a reversible electric'motor. andi means' connected therewithf to' operatethe door,` a source offelectric power, `a'. reversible4 switch'. operated: by the; saidk connectedv means: and A arrangedI to connect .the :motor selec- .75 tively :in reversedirections toi-the source.' of fpower, an electro-magnetic power device connected to the reversible switch and operative when energized to move the switch from its closing position to its opening position, a relay in control of the power device, a circuit adapted to connect the relay with the source of electric power including normally open contact elements carried by the door and adapted to be closed by engagement with a relatively stationary body, a normally closed cut-off switch in said circuit, and means operated by the said connected means near the limit of the opening movement of the door to open the cut-olf switch.

3. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of solenoids having corresponding ends connected respectively to opposite sides of the switch and -having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the solenoids and adapted to connect the motor selectively in reverse directions to the source of power, a shunt circuit connected across the solenoids and adapted when closed to short circuit the solenoids and including a normally open contact, a relay adapted when energized to close the said contact, and means for connecting the relay in circuit with the source of power, said means including the reversing switch and normally open contact elements carried by the door in position to be closed when engaged by a relatively stationary body as the door is closing.

4. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the vsaid reversing means, a pair of solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the solenoids and adapted to connect the motor selectively in reverse directions to the source of power, a shunt circuit connected across the solenoids and adapted when closed to short circuit the solenoids and including a normally open contact, a relay adapted when energized to close the said contact, means for connecting the relay in circuit with the source of power, said means including the reversing switch and normally open contact elements carried by the door in position to be closed when engaged by a relatively stationary body as the door is closing, a normally closed cut-off switch in the relay circuit, and means operated by the door near the limit of its opening movement to open the cut-01T switch.

5. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the solenoids and adapted to connect the motor selectively in reverse directio-ns to the source of power, a shunt circuit connected across the solenoid-s and adapted when closed to short circuit the solenoids and including a normally vopen contact, a relay adapted when energized to close the said contact, meansy for connecting the relay in circuit with the source of power, said means including normally open contact elements carried by the door in position to be closed when engaged by a relatively stationary body as the door is closing, a reopen magnet connected to the reversing switch and operative to move the switch from its closing position to its opening position, and an energizing circuit for the magnet including a normally open contact adapted to be closed by the relay.

6. The combination of a door, a source of electric power, a reversible electric motor and means connected therewith to operate the door, a reversible switch arranged to connect the motor selectively in reverse directions to the source of power, a reopen magnet including an armature, a lost motion connection between the armature and the switch adapted to allow the switch to reverse freely when the armature is unattracted and to move the switch from closing to opening position when the armature is attracted, a pivoted lever having operative connection with the switch, means operated by the said connected means to reciprocate the lever at the limits of movement of the door and thus reverse they switch, a relay in control of the reopen magnet, and means for energizing the relay including normally o-pen contact elements carried by the door and adapted to be closed by engagement with a relatively stationary body.

'1. The combination of a door, a Source of electric power, a reversible electric motor and means connected therewith to operate the door, a reversible switch arranged to connect the motor selectively in reverse directions to the source of power, a reopen magnet including an armature, a lost motion connection between the armature and the switch adapted to allow the switch to reverse freely when the armature is unattracted and to move the switch from closing to opening position when the armature is attracted, a pivoted lever having operative connection with the switch, means operated by the said connected means to reciprocate the lever at the limits of movement of the door and thus reverse the switch, a relay in control of the reopen magnet, a circuit adapted to connect the relay with the source of electric power including normally open contact elements carried by the door and adapted to be closed by engagement with a relatively stationary body, a normally closed cut-off switch in said circuit, and means loperated by the said connected means near the limit of the opening movement of the door to open the cut-off switch.

8. The combination of a do-or, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the solenoids and adapted to connect the motor selectively in reverse directions to the source of power, a normally closed stop switch in the common lead, a stop solenoid operative when energized to open the stop switch, and'a circuit for connecting the stop solenoid to the source of power including the reversing switch and a normally open contact member carried by the door and adapted to close the circuit when engaged by a relatively stationary body as the door moves.

9. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of motor controlling solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the motor controlling solenoids and adapted to connect the motor selectively in reverse directions to the source of electric power, a normally closed stop switch in the common lead, a stop solenoid operative when energized to open the stop switch, and a circuit for connecting the stop solenoid to the source of electric power including the reversing switch and a normally open contact member carried by the outer face of the door and adapted to close the circuit when engaged by a relatively stationary body as the door is opening.

10. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of motor controlling solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the motor controlling solenoids and adapted to connect the motor selectively in reverse directions to the source of electric power, a normally closed stop switch in the common lead, a stop solenoid operative when energized to open the stop switch, a circuit for connecting the stop solenoid to the source of electric power including the reversible switch and a normally open contact member carried by the outer face of the door and adapted to close the circuit when engaged by a relatively stationary body as the door is opening, a shunt circuit connected across the motor controlling solenoids and including a normally open contact, a relay adapted when energized to close the said contact, and means for connecting the relay in circuit with the source of power, said means including the reversible switch and normally open contact elements carried by the door in position to be closed when engaged by a relatively stationary body as the door is closing.

11. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by the said connected means, a pair of motor controlling solenoids having corresponding ends connected respectively to opposite sides of the switch and having their other ends connected in parallel to a common lead connectible to the source of electric power, reversing contacts controlled respectively by the motor controlling solenoids and adapted to connect the motor selectively in reverse directions to the source of electric power, a normally closed stop switch in the common lead, a stop solenoid operative when energized to open the stop switch, a circuit for connecting the stop solenoid to the source of electric power including the reversible switch and a normally open contact member carried by the outer face of the door and adapted to close the circuit when engaged by a relatively stationary body as the door is opening, an electromagnetic power device connected to the reversible switch and operative when energized to move the switch from its closing to its opening position, a relay in control of theV power device, and means for energizing the relay including the reversible switch and normally open contact elements carried by the door and adapted to be closed by engagement with a relatively stationary body.

l2. The combination of a door, a reversible electric motor and means connected therewith to operate the door, a source of electric power, a reversible switch operated by said connected means, a motor control circuit for controlling the connection of the motor to the power source controlled by the reversing switch and including a normally closed contact, a stop solenoid operative when energized to open the normally closed contact, and a circuit for connecting the stop solenoid to the source of electric power including the reversible switch, and a normally open contact member carried by the outer face of the door and adapted to close the circuit for the stop solenoid when engaged by a relatively stationary body as the door is opening.

CHARLES OPALEK,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,574,197 Hynes Feb. 23, 1926 1,642,317 Webb Sept. 13, 1927 1,682,254 Rorabacher Aug. 28, 1928 1,745,990 Goldman Feb. 4, 1930 2,253,170 Dunham Aug. 19, 1941 2,342,597 Opalek Feb. 22, 1944

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