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Publication numberUS3864875 A
Publication typeGrant
Publication dateFeb 11, 1975
Filing dateApr 16, 1973
Priority dateApr 16, 1973
Also published asCA1006552A1
Publication numberUS 3864875 A, US 3864875A, US-A-3864875, US3864875 A, US3864875A
InventorsLew V Hewitt
Original AssigneeOverhead Door Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Swing door operator
US 3864875 A
Abstract
A door operator for a door movable between open and closed positions. The operator includes an endless loop member supported for reversible orbital motion by a pair of spaced rotatable members. A linkage couples one rotatable member to the door. A pressure fluid cylinder has a piston rod connected to one reach of the endless loop member and is actuable in one direction for moving the endless loop member to open the door. Resilient tension return means are coupled to the other reach of the endless loop member and are responsive to cessation of actuation of the pressure fluid cylinder for causing the endless loop member to close the door. The pressure fluid cylinder includes means for decelerating door motion as the door approaches its open and closed positions, including enlarged cam portions on the piston rod thereof cooperating with valved pressure fluid inlet and outlet openings. A control circuit having a variable time delay responds to actuation of actuation and safety switches, by persons using the door, for controlling pressure fluid flow to the cylinder. By appropriate installation, the operator is usable with either right- or left-hand hinged doors and doors which open either inwardly or outwardly. A modified operator substitutes a direct drive connection for the linkage. Other modified operators are usable with sliding doors and with double swinging doors.
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Description  (OCR text may contain errors)

United States Patent [191 Hewitt [4 1 Feb. 11, 1975 SWING DOOR OPERATOR [75] Inventor: Lew V. Hewitt, Corpus Christi, Tex.

[73] Assignee: Overhead Door Corporation, Dallas,

Tex.

[22] Filed: Apr. 16, I973 [21] Appl. No.: 351,460

Primary E.\'aminer.l. Karl Bell Attorney, Agent, or Firm-Woodhams, Blanchard & Flynn [57] ABSTRACT A door operator for a door movable between open and closed positions. The operator includes an endless loop member supported for reversible orbital motion by a pair of spaced rotatable members. A linkage couples one rotatable member to the door. A pressure fluid cylinder has a piston rod connected to one reach of the endless loop member and is actuable in one direction for moving the endless loop member to open the door. Resilient tension return means are coupled to the other reach of the endless loop member and are responsive to cessation of actuation of the pressure fluid cylinder for causing the endless loop member to close the door. The pressure fluid cylinder includes means for decelerating door motion as the door approaches its open and closed positions, including enlarged cam portions on the piston rod thereof cooperating with valved pressure fluid inlet and outlet openings. A control circuit having a variable time delay responds to actuation of actuation and safety switches, by persons using the door, for controlling pressure fluid flow to the cylinder. By appropriate installation, the operator is usable with either rightor left-hand hinged doors and doors which open either inwardly or outwardly. A modified operator substitutes a direct drive connection for the linkage. Other modified operators are usable with sliding doors and with double swinging doors.

26 Claims, 15 Drawing Figures SHEET E OF 7 SWING DOOR OPERATOR FIELD OF THE INVENTION This invention relates to a door operator and more particularly relates to a door operator for switch controlled opening and closing of a door, particularly a swinging door.

BACKGROUND OF THE INVENTION The door operator embodying the present invention was developed to fulfill long felt needs in apparatus of this type. More particularly, although mat actuated power operated doors have long been known and a wide variety of door and operator systems has been proposed in the past, same have not proven entirely satisfactory for a variety of reasons. Many prior door operators have been of high mechanical complexity, resulting in high manufacturing and maintenance costs and unreliability in long-term use. Many prior door operators have not been versatile in application, being limited to use with a particular kind of door, e.g. swinging, sliding, etc. Swinging door operators have in the past further frequently been incapable of use with both leftwardly and rightwardly hinged doors or both inwardly and outwardly swinging doors or have required substantial modification or replacement of parts to accomplish a change-over from one type of swinging door to another, requiring large and costly inventories of disparate door operator models and replacement parts for each.

Accordingly, the objects of this invention include provision of:

l. A door operator of a simplified mechanical construction having relatively few parts and capable of use with little or no replacement of parts on a wide variety of door types.

2. A door operator, as aforesaid, usable with swinging doors, including bi-fold doors, and sliding doors as well.

3. A door operator, as aforesaid, usable with either right-handed or left-handed swinging doors without replacement of parts, simply by reorienting the door operator unit as a whole and repositioning the linkage by which it connects to the door.

4. A door operator, as aforesaid, usable with either inwardly or outwardly opening doors, by a minor rearrangement of parts therewith and, in some instances, by use of differing linkage lengths connected to the differing door types.

5. A door operator, as aforesaid, capable of use with either single or tandem doors and which is'capable of maintaining synchronism of door opening in tandem door installations.

6. A door operator, as aforesaid, capable of connection to doors in several ways, e.g., through a linkage or directly through a rotating drive element.

7. A door operator, as aforesaid, which provides for deceleration of door movement to a fully opened or fully closed position, in a smooth and accurately controllable manner.

8. A door operator, as aforesaid, providing for reliable closing of the door automatically and despite power failures and the like, and also in case of fire and other specified events, so as to be usable as an automatically closing fire door.

9. A door operator, as aforesaid. which automatically prevents opening of a swinging door into a person or the like standing in the path thereof.

apparent to persons acquainted with apparatus of this.

general type upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partially broken elevational view ofa door operator embodying the invention, mounted in operative relation with a left-hand hinged, inwardly swinging door.

FIG. 2 is an enlarged sectional view substantially taken on the line Il--II of FIG. 1.

FIG. Sis a fragmentary sectional view substantially taken on the line III-III of FIG. 2.

FIG. 4 is a diagrammatic central cross-sectional view of the pressure fluid cylinder of FIG. 2, with associated valving, with the piston rod shown in the door-closed position.

FIG. 5 is a view similar to FIG. 4 but showing an intermediate position of the piston rod during door opening movement.

FIG. 6 is as view similar to FIG. 4 but showing the piston rod positioned as the door approaches its fully open position.

FIG. 7 is a schematic diagram of electrical circuitry which comprises a portion of the operator of FIG. 2.

FIG. 8 is a view similar to FIG. 2 but showing the door operator reoriented for use with a right-hand hinged door.

FIG. 9 is a view similar to FIG. 2 but showing the operator arranged for use with an outwardly swinging door.

FIG. 10 is a view similar to FIG. 2 but showing a modified operator positioned directly above the door and arranged for direct drive opening thereof.

FIG. 11 is an elevational view disclosing a modification wherein the door is a sliding rather than swinging door.

FIG. 12 is a fragmentary elevational view of a door operator modified for synchronized opening of a pair of swinging doors.

FIG. 13 is a top elevational view of the apparatus of FIG. 12 and utilizing the operator of FIG. 2 as a portion thereof.

FIG. 14 shows a modification of the FIG. 4 apparatus.

FIG. 15 is a modified fragment of FIG. 7 related to FIG. 14.

SUMMARY OF THE INVENTION The objects and purposes of the invention are met by providing a door operator for a door movable between open and closed positions. The operator includes an endless loop member supported for reversible orbital motion by a pair of spaced rotatable members. A linkage couples one rotatable member to the door. A pressure fluid cylinder has a piston rod connected to one reach of the endless loop member and is actuable in one direction for moving the endless loop member to open the door. Resilient tension return means are coupled to the other reach of the endless loop member and are responsive to cessation of actuation of the pressure fluid cylinder for causing the endless loop member to close the door. The pressure fluid cylinder includes means for decelerating door motion as the door approaches its open and closed positions, including enlarged cam portions on the piston rod thereof cooperating with valved pressure fluid inlet and outlet openings. A control circuit having a variable time delay responds to actuation of actuation and safety switches, by persons using the door, for controlling pressure fluid flow to the cylinder. By appropriate installation, the operator is usable with either rightor left-hand hinged doors and doors which open either inwardly or outwardly. A modified operator substitutes a direct drive connection for the linkage. Other modified operators are usable with sliding doors and with double swinging doors.

DETAILED DESCRIPTION FIG. 1 discloses the interior face of a building wall 11 provided with a portal 12 defined in part by spaced, upstanding stiles 13 and 14. The portal is occupied by an inwardly swinging door 16 pivotally supported by hinges 17 and 18 on the leftward stile 13.

A door operator 20 is fixed on the interior face of the wall 11 above the door 16 for opening and closing said door, as hereinafter discussed.

The operator 20 (FIGS. 2 and 3) includes a housing 22, of horizontally elongate and generally rectangular form, comprising a back wall 24, front wall 25, end walls 26 and 27, a top wall 28 and bottom wall 29. In the particular embodiment shown, the back wall 24 is preferably secured to the stiles 13 and 14 by any conventional means, such as screws not shown. At least a portion of the housing 22, preferably including the front wall 25, is removable for access to the contents of the housing.

The door operator 20 further includes within the housing 22 a pressure fluid motor unit 31 with associated valving 33, a variable time delay control 34 for controlling such motor unit 31, resilient return means 36 and an endless loop unit 38, responsive to the motor unit 31 and return means 36, for opening and closing the door 16.

The motor unit 31 (FIGS. 2 and 3) comprises a pressure fluid (here air) cylinder 41 having end walls 43 and 44, respectively provided with bosses 46 and 47 extending coaxially therefrom. Angle brackets 51 and 52 are fixed to the cylinder end 43 and have horizontally extended portions pivotally secured to the top and bottom housing wall 28 and 29, as by coaxial bolts 54, so as to cantilever the pressure fluid cylinder within the housing 22 for horizontal pivoting thereof. An elongate piston rod 56 extends from within the pressure fluid cylinder 41 coaxially outwardly through the wall 44 and boss 47.

The return means 36 comprises a reversible bracket 61 of generally U-shaped configuration, having upper and lower legs 62 removably affixed, by any convenient means such as screws 63, to the top and bottom walls 28 and 29 of the housing. An upstanding bight portion 65, preferably integrally extends between corresponding ends of the legs 62 and is near an intermediate portion of the cylinder 41. Resilient tension means, here comprising a pair of substantially horizontally extending, coiled tension springs 66 and 67, are fixed at one end to the bracket 61 and extend therefrom generally along the cylinder 41 and piston rod 56 toward the endless loop unit 38.

The endless loop unit 38 comprises an upstanding actuating, or door drive shaft 69 (FIGS. 2 and 3) located 74 is fixed on the shaft 69 by a hub 76 in a conventional manner, between the bearings 71 and 72. A rotatable idler member 78 of similar type but smaller diameter is supported in horizontal, coplanar relation with the member 74 adjacent and between the piston rod 56 and springs 66 and 67. In the preferred embodiment shown, the idler 78 is rotatably secured atop a support 79 (FIG. 3) carried by and fixed to the bottom wall 29 of the housing. An endless loop member 81 snugly encircles the members 74 and 78 and positively drives the former. The endless loop member 81 may be a conventional chain and the members 74 and 78 may be sprockets. However, in the particular embodiment shown, the member 81 is a toothed timing belt and members 74 and 78 are correspondingly toothed pulleys, the timing belt and pulleys being of known type. The free ends of the piston rod 56 and springs 66 and 67 are fixed to the outer surfaces of opposite reaches 84 and 85, respectively, of the belt 81 between the pulleys 74 and 78 and by means of suitable clamps or brackets 87 and 88, respectively.

A drive linkage 91 couples the lower end of shaft 69 to the door 16 and comprises a pair of pivotally connected links 93 and 94. The free end of link 93 is removably fixed to the lower end of shaft 69 as generally indicated at 96 and by any convenient means. The free end of link 94 is pivotally secured at 97 to a bracket 98 fixed to the interior face of door 16 at the top thereof and is spaced inboard from the hinged edge thereof.

As generally indicated in FIGS. 4-6, the pressure fluid cylinder 14 includes an elongate, hollow, cylindrical wall 101 extending coaxially between the end walls 43 and 44 and defining a hollow, elongate piston chamber 102.

The bosses 46 and 47 are hollow and define a back check chamber 104 and a latch check chamber 105. The chambers 104 and 105 communicate coaxially withthe piston chamber 102 through guide openings 106 and 107, respectively and open through the free ends of the bosses 46 and 47 via coaxial ports 108 and 109. The port 109 is provided with an annular seal 110 sized for slideably receiving piston rod 56 therethrough.

The interior end (leftward in FIG. 4) of piston rod 56 coaxially carries a radially enlarged piston 112 reciprocable between the ends of chamber 102. Radially extending seal members 113 on the piston 112 slideably engage the cylinder wall 101 to prevent leakage past the piston 112. The piston rod 56 further includes a pair of radially enlarged, coaxial cam portions 116 and 117, which extend leftwardly and rightwardly from the piston 112 and are snugly but slideably receivable through guide openings 106 and 107, respectively. Annular seals 118 and 119 are provided within the bosses 46 and 47, adjacent the guide openings 106 and 107, for sealingly engaging the cam members 116 and 117, respectively, when the piston rod is respectively adjacent its leftward and rightward extremes of travel. The remote ends 121 and 122 of cam members 116 and 117 are tapered, the former being rounded at its end extremity.

. through which is controlled by a threaded, axially adjustable needle valve 128. An outlet opening 130 is provided on the needle 'valve side of the orifice 129 whereby the rate of air flow through the opening 130, orifice 129 and passage 125 may be controlled by the setting of the needle valve 128.

The valving 33, as shown diagrammatically in FIG. 4, includes a casing 133, here shown as fixed to the end wall 44 and boss 47, which through a conduit 134 communicates with a solenoid valve assembly 135. The latch check chamber 105 communicates directly through a port 136 with conduit 134. An eccentrically located passage 138 communicates between the piston rod (rightward in FIG. 4) end of chamber 102 and conduit 134 and contains, in parallel, a restrictive orifice unit 140 and a one-way valve 142. The restrictive orifice unit 140 is preferably similar to the restrictive orifice unit 124, above described, including a similar restrictive orifice, needle valve and opening in series. The one-way valve 142 is oriented to allow free air flow from the conduit 134 therethrough into passage 138, but to positively prevent reverse flow, and may, for example, comprise a conventional ball check valve.

The solenoid valve assembly 135 comprises a casing 146 having a chamber 147. A reciprocable plunger, or valve element 144, is slidable in the chamber 147. The conduit 134 communicates with the chamber 147. A source S of pressure fluid, of any conventional nature, here capable of supplying pressurized air at 40psi, communicates through a conduit schematically indicated at 149 and a passage 150 with the chamber 147. The passage 150 is, in the rest position of the apparatus, normally closed by the solenoid plunger 144.

In the preferred embodiment shown, a conventional thermally actuable valve TV is interposed in the conduit 149 and is responsive to fire within the building for venting the passage 150 and preventing application of air pressure from the source S thereto. Normally however, the valve TV simply acts as a part of the conduit 149, conveying pressurized air from the source S to passage 150.

A further restrictive orifice unit 152, preferably similar to the unit 128 above described, connects through a further passage 154 with the solenoid valve chamber 147. A further oneway valve 155 (e.g. a ball check valve) connects between passage 154 and the atmosphere, to allow free air flow into passage 154 but block reverse flow therethrough. The passage 154 is closeable by the solenoid plunger 144 upon actuation of a solenoid 156 (as shown in FIG. 5).

The solenoid 156, as schematically indicated in FIGS. 4 and 5, is of the electrically actuated, springreturn type and the valve element 144, as shown by dotted line 158, is preferably connected to, or forms a part of, the movable solenoid element 159.

In the preferred embodiment shown, the door operator structure above described is controlled by electrical circuitry shown schematically in FIG. 7. AC operating potential from any convenient source, for example a conventional 110 volt AC source, is applied through a voltage reduction and/or isolation transformer 161 to an AC line 162 and, through a main power on-off switch 163, to a further AC line 164. Conventional treadle, or mat, operated switches, comprising an actuating switch 166 and a safety switch 167, are provided on opposite sides of the door 16, the door 16 normally being arranged to swing over the safety mat and away from the actuating mat, as shown. The AC lines 162 and 164, mat switches 166 and 167 and opening solenoid 156 are connected to the variable time delay door control circuit 34 preferably through a separable multiterminal connector 169.

The control 34 includes a double-pole, double-throw relay RRl, incorporating a winding W1 and two double-throw switches S1 and S1, each having a movable contact and upper and lower alternatively selectable fixed contacts. The'control 34 further includes singlepole, single-throw relays RR2 and RR3 having actuatable windings W2 and W3. The movable contacts of switches S1 and S1 are in their downward position shown and the contacts of relays RR2 and RR3 are open in the rest condition of the control. The AC line 164 connects to the winding W1 and lower fixed contact of switch S1. The movable contacts of switch S1 and switch S1 connect across winding W2. The lower fixed contact of switch S1 connects through a line 170, and the actuating switch 166 to the other AC line 162. Thus, closure of the actuating switch 166 completes a circuit through line 170, switch S1, the winding W2 and switch S1 to the AC lines, thus energizing winding W2.

A diode 172, parallelled by a surge protector, 173 connects from AC line 162 to the fixed switch contact of relay RR2 and through a capacitor 174 to the other AC line 164.

A transistor T1 is connected at its emitter to AC line 164 and at its collector through winding W3 and a resistor R6 to the cathode of diode 172 and thence to the other AC line 162. Thus, DC potential is applied through this path to the transistor T1. The movable contact of relay RR2 connects through series resistors R3 and R4 to the base of transistor T1. A point between the resistors R3 and R4 connects through a capacitor C2, paralleled by a series resistor R2 and potentiometer R1, to AC line 164. Thus, closure of the contacts of relay RR2 by actuation of the winding W2 applies positive bias from the diode 172 to the base of transistor T1, rendering same conductive through the winding W3 of relay RR3.

The normally open contact of relay RR3 connects in series with a resistor R5 from the AC line 164 to the gate of a triac D2. The main electrodes of triac D2 connect from the AC line 164 through a line 176 and the opening solenoid 156 to the other AC line 162. Thus, upon actuation of the coil W3, the contact of relay RR3 applies gate potential from the AC line 164 to the triac D2, rendering same conductive through the solenoid 156 to energize the latter.

The winding W1 of relay RRl connects from AC line 164 through a line 177 and safety switch 167 to the other AC line 162. The AC line 162 also connects to the upper fixed contacts of switch S1 in relay RR1. A line 178 connects the upper contacts of switch S1 to the lower end of triac D2.

OPERATION To ready the door operator for operation, the power switch 163 (FIG. 7) is closed, providing AC operating potential across lines 162 and 164. The door 16 is normally closed and the remaining switches of the circuitry of FIG. 7 are in their solid-line positions shown. The piston rod 56 of the pressure fluid cylinder is in its extended position shown in FIGS. 4 and 2 and the sole noid 156 is in its unenergized state of FIG. 4.

Considering the normal operation of the door operator, a person approaching the closed door 16 (FIG. 7) from the outside steps on the actuating mat (preferably immediately in front of the door), closing the actuating switch 166. This completes the circuit between the AC lines through switch S1, winding W2 and switch 81, thereby energizing winding W2 to close the contacts of relay RR2. Such closure supplies positive base bias from AC line 162 through diode 172 and resistors R3 and R4 to transistor T1. Transistor Tl then conducts from AC line 162 through diode 172, resistor R6, the winding W3 and thence to the other AC line 164, energizing winding W3. Closure of the relay RR2 contact also applies charging current to capacitor C2 causing the lower plate thereof to rapidly accummulate a positive charge.

The energized winding W3 closes the contact of relay RR3, applying gate potential to the triac D2 through resistor R5 from AC line 164 and rendering the triac conductive. The conductive triac D2 connects operating solenoid 156, through line 176 across the AC lines 162 and 164, thus energizing such solenoid.

Energization of solenoid 156 shifts the plunger 144 thereof rightwardly from its at rest position shown in FIG. 4, to its position of FIG. 5. Thus, pressurized air from source S enters the casing 146 through passage 150, passes the solenoid plunger 144, and moves through conduit 134 into the casing 133. Such air then passes freely through one-way valve 142 and eccentric passage 138 into the rightward end of the chamber 102 to move the piston 112 leftwardly, retracting piston rod 156. Such air from conduit 134 also passes freely through latch check port 136 and into the latch check chamber 105, acting on the cam portion 117 to assist in driving the piston 112 leftwardly and removing the cam 117 from the latch check chamber. Air pushed leftwardly, ahead of the piston 112, freely exits the chamber 102 through the free flow port 108, and to an extent through the orifice unit 124.

As the piston rod 56 nears the left end of its stroke, the nose 121 of cam 116 (FIG. 6) passes through the guide opening 106 and seal 118 into the back check chamber 104, at first partly, then completely, preventing air pushed ahead of the retracting piston 112 from exiting chamber 102 through the free flow port 108. Thereafter, such air can only exit the chamber 102 at a controlled, low rate through the restrictive orifice unit 124. This causes the retracting piston rod 56 to slow smoothly, over a substantial portion of its travel, until it comes to rest with the piston 112 adjacent the leftward, or blind, end of the cylinder 41.

As seen in FIGS. 2 and 3, such retraction of the piston rod 56 pulls the upper reach 84 of the belt 81 toward the idler pulley 78, orbiting the belt 81 (clockwise in FIG. 2) and moving the lower reach 85 of the belt leftwardly, pulling the clamp 88 leftwardly and tensioning and extending springs 66 and 67. Such orbiting of the belt also positively rotates the guide pulley 74 and shaft 69 to rotate the link 93 clockwise to its broken line position 93'. This in turn pulls the link 94 downwardly and leftwardly (FIG. 2) to open the door 16. Thus, as piston rod 56 decelerates gradually to a stop in its retracted position, the door 16 decelerates smoothly to its open position 16', remote from a person standing on the actuating mat (FIG. 7).

The apparatus will stay in its state Iast'mentioned. with the door open, while the person walks or stands on the actuating mat 166. Normally, however, upon opening of the door, the person will advance through the open doorway and onto the safety mat 167. As the person leaves the actuating mat, the switch 166 opens, deenergizing relay RR2. However, transistor T1 remains conductive for a delay period determined by the discharge time of capacitor C2 through resistor R2 and potentiometer R1. Thus, W3, triac D2 and solenoid 156 remain actuated during this delay. The length of the delay is adjustable by potentiometer R1. This delay gives the person a sufficient time to pass through the open doorway before the door 16 closes.

A person so passing through the doorway then normally steps on the safety mat, closing the switch 167 within such delay period. Thus, the winding WI of relay RR] is energized through safety switch 167 across AC lines 162 and 164 and shifts the contacts of switches S1 and S1 upwardly to their dotted line positions of FIG. 7. In consequence, current flows through the AC line 162, switch S1, winding W2, switch S1, line 178, the still conductively biased triac D2 and the remaining AC line 164. The resultant reenergizing of winding W2 closes the relay RR2 contact to reestablish the charge on capacitor C2, and continues to bias transistor T1 and thereby continue conduction of triac D2 while the safety switch remains closed. This continues energization of the solenoid 156 to hold the door open.

As the person leaves the safety mat, the safety switch 167 opens. Such removes AC potential from winding W1, allowing switches S1 and S1 to return to their solid line positions of FIG. 7 and deenergizing winding W2. After capacitor C2 discharges through the time delay period, transistor T1 shuts off, deenergizing winding W3, whereafter the triac D2 shuts off, deenergizing solenoid 156. The delay period is sufficient to allow the person to move well beyond the safety mat and out of the path of the door 16.

Upon deenergization of the solenoid 156, the movable solenoid element returns to its rest position, by means of a suitable spring in a known manner, shifting the valve element 144 leftwardly to its position of FIG. 4, preventing supply of pressurized air from source S to the conduit 134, and opening the conduit 134 to the restrictive orifice unit 152.

The piston rod 56 is then free to return rightwardly from its retracted position of FIG. 6. The tension springs 66 and 67 (FIGS. 2 and 3) then contact, pulling the lower reach of belt 81 rightwardly, orbiting the belt 81 counterclockwise, and moving the upper reach 84 leftwardly. Such pulls, or extends, the piston rod 56, rotating the drive pulley 74 counterclockwise to cause the link 93 to return the door 16 to its fully closed position.

During such piston rod extension, the piston 112 (FIGS. 4 through 6) moves rightwardly, drawing air behind it into chamber 102, primarily through the free flow port 108. Air pushed ahead of the moving piston 112 flows freely through latch check chamber 105, port 136, conduit 134 and then, in a restricted manner, out the restrictive orifice unit 152. Thus, the unit 152 limits the maximum closing speed of the door.

As the piston rod 56 nears full extension, the tapered nose 122 of cam 117 enters the guide opening 107, the taper of the nose 122 progressively restricting air flow into the latch check chamber 105 and gradually decelerating the piston rod. After the nose 122 has passed the seal 119, no further air can be pushed by piston 112 into the latch check chamber 105 and all air pushed ahead of the piston 112 must flow into port 138 and thence through restrictive orifice unit 140 (the oneway valve 142 being positively closed to air flow in this direction). Thus, restrictive orifice unit 140 further restricts exhaust air flow, further slowing and extending piston rod 56 and closing door so that the last increment of closing door movement is gradual. The chambers 104 and 105 (FIG. 4) and corresponding cam members 116 and 117 are relatively long, compared to the total stroke of the piston rod 56 (here totalling about one-third of said stroke length), so that deceleration of the door as it approaches the ends of its travel is indeed gradual.

This completes the normal opening and closing cycle of the door operator of FIGS. 1 through 7.

If, at any time during the opening and closing cycle of the door, the actuating switch 166 is again closed, the cycle immediately begins anew and proceeds in the manner above discussed.

To avoid the possibility of the door opening and striking a person in its path, the safety mat normally covers the area near and swept by the opening door. Thus, a person adjacent the closed door, standing in its path and on the safety mat, will close the safety switch 167. With the apparatus of FIGS. 1 through 7 in its rest position shown (door closed, triac D2 off), closure of the safety switch 167 has no effect on the door. More particularly, closure of the safety switch 167 will energize winding W1, switching the contacts of switches S1 and S1 to their dotted line positions, and thereby coupling winding W2 in series with triac D2 across the AC line 162 and 164. However, triac D2, being off, cannot supply current to winding W2. In consequence, transistor T1, relay RR3 and the triac D2 remain nonenergized and the door does not open. Further, while the safety switch 167 is closed, closing of actuating switch 166 has no effect since switch S1 no longer couples the line 170 to the winding W2. Thus, actuation of the safety switch 167 prevents subsequent closing ofthe actuating switch 166 from opening the door.

With the provision of the thermal valve TV, above discussed, the door 16 can be used as a fire door. More particularly, the door normally functions as an automatic door (as above described), but in case of fire would be relieved of air pressure from source S by the thermal valve TV, whereby the springs 66 and 67 would resiliently urge the door to its closed position and the door would no longer be opened by switches 166. On the other hand, the door could be manually opened in such instances (or in any other instances wherein air pressure is not supplied to the conduit 134 from the source S) by manually pulling, or pushing, open the door 16 against the reslient force of the springs 66 and 67, atmospheric pressure being maintuined behind (to the right in FIG. 4) the piston 112 by, for example, leakage through the check valve 155.

For emergency use, an emergency switch, not shown, may be provided, for example in series with the solenoid 156 across the AC lines 162 and 164, for energizing such solenoid to open the door.

The door operator embodying the invention can, in the absence of air supply to the cylinder 41, be employed as a resilient door closer with a checking, or door decelerating, action toward the end of the door closing movement. Under such conditions, the door can be opened manually against the force of the springs 66 and 67.

It may be desired, or required by local building codes, that the door requires no more than a specified maximum force to open in the event of failure of its automatic operator. Thus, should the timing belt 81 (FIG. 2) become immobilized, the guide pulley 74, in response to a preselected and greater than normal torque on the shaft 69 and door, will slip with respect to the belt, allowing opening or closing of the door. A similar effect can be achieved in FIG. 10, hereinafter discussed, by providing a presettable slip clutch of conventional type (not shown) between the sprocket 74C and shaft 69C, for example.

If desired, the ratio of pressure fluid cylinder stroke and door opening angle can be varied, as for example by interposing a ratio changing gear train or the like between the driven pulley 74 and shaft 69, or more simply, by changing the diameter of the pulley 74 or the length of link 93 or the location of bracket 98.

MODIFICATIONS The operator embodying the invention can be used with doors of either hand, that is, doors hinged at either their left or right sides. While FIG. 2 shown the operator 20 used with an inwardly swinging door 16 hinged at its left side, FIG. 8 discloses the operator 20 rearranged for operating a door 16A hinged at its right side, as indicated at 17A. Such is accomplished by rotating the door operator 20 about an axis perpendicular to the wall 11 through 180, so that the drive pulley 74 is adjacent the hinge 17A. The linkage 93, 94 is then connected to the other exposed end of the shaft 69, now extending downwardly. Thus, the same operator 20 can be used with both left-hand and right-hand hinged doors simply by a rotation thereof and reconnection of the linkage 93, 94.

As shown in FIG. 9, the operator 20 can also be used with an outwardly swinging door 168 of either hand, here for example left-hand hinged at 178. To accomplish this conversion, the bracket 61 is disconnected from the housing walls and rotated 180 degrees about a vertical axis and reconnected, to place the bight 65 thereof adjacent the housing back wall 24 instead of the front wall 25. The springs 66, 67 and piston rod 56 are disconnected from belt 81. The fluid cylinder 41 is then pivoted on pivot 54 toward the front wall 25 of the housing to place the piston rod 56 in front of idler pulley 78. To facilitate such shifting, the idler pulley 78 may be temporarily removed. Thereafter, the springs 66, 67 are connected to the reach 84 (in back of the fluid cylinder 41) and the piston rod 56 is connected to the front reach 85 of the belt. In this way, the retracting piston rod 56 and spring pair 66, 67 will rotate the drive pulley 74 in reversed directions as compared to their arrangement of FIG. 2. Longer links 93B and 94B may replace the links 93 and 94 of FIG. 2. Thus, retraction of piston rod 56 will still open the door 16B, as in FIG. 2, but by rotation of pulley 74 in the opposite direction.

It will be understood that the operator 20, arranged as in FIG. 9, can be rotated through about an axis perpendicular to the building wall and with repositioning arm 938 at the other end of shaft 69, can be used with right-hand hinged, outwardly swinging doors.

Thus, the same door operator assembly can accommodate all of the four possible combinations of door hinging and opening directions, i.e., right-hand hinge, left-hand hinge, interior opening, and exterior opening.

In FIG. 10, a modified door operator 20C is disposed in a space in the wall between stiles 13C and 14C and in overlapping fashion above the door (indicated in a broken line at 16C in its normal closed position). The operator housing 22C is fixedly located, for example by securement to stile 13C and 14C, by any convenient means not shown. The modified door 16C is of the type pivotally supported by coaxial shaft offset inboard from the edge of the door and extending vertically upwardly and downwardly therefrom, the shafts being pivoted, for example, in a suitable socket, not shown, in the building floor and/or in the area directly above the door. In the particular embodiment shown, the upwardly extending door pivot shaft connects to or is in extension of a shaft 69C, rotatably supported by the housing 22C as in FIG. 3. Thus, rotation of the shaft 698 rotates the door 16C to and from its open position shown in 16C, in response to rotation of the drive member 74C.

The door operator 20C of FIG. is further modified in that members 74C and 78C comprise sprockets and the endless loop member 81C comprises a chain.

It should be noted that the direct drive arrangement of FIG. 10 requires a lesser angle of rotation by drive member 74C to affect a given angle (for example 90) of door pivotal motion, the angle of rotation of the drive member 74C and door being the same in FIG. 10. In contrast, the drive member 74 of FIGS. 2, 8 and 9 may traverse an angle between 90 and l80 for a 90 opening movement of the corresponding door. Thus, a pressure fluid cylinder of shorter stroke or a larger drive member diameter may be employed in the modified FIG. 10 apparatus.

FIG. 11 discloses a modified door operator D similar to the operator 20 but adapted for use in opening and closing a sliding door 183. The operator 20D is located above the upper track 185 of the sliding door and except as in hereinafter discussed basically comprises the door operator 20 as shown in FIG. 8 but rotated about its length axis through an angle of 90 and so that the drive shaft 69D is horizontal and has one end thereof forwardly overhanging the front face of the door 183. The door 183 has fixed to its upper rightward face a vertical track element 187 having a longitudinal undercut groove. A link 93D is fixed to the exposed end of shaft 69D and extends therefrom into pivotal connection with a slider 188 vertically slidable within the track element 187. Thus, upon counterclockwise rotation of the shaft 69D, the link 93D swings, thus simultaneously sliding downward along the track element 187 and causing the door 183 to slide rightwardly along its track to its open position indicated in broken lines at 183'. Reversal of the rotation of the shaft 69D reverses the sliding motion of the door 183 to return same to its closed solid line position of FIG. 11.

The operator 20 can thus also be arranged to actuate gates and folding doors, in the latter instance, for example, either panel of a conventional, hinge connected bifold door pair.

FIGS. 12 and 13 disclose a modified door operator system 191 for opening and closing a double, or tandem, door arrangement, comprising a pair of doors 16E and 16F. Such doors 16E and 16F when closed are substantially coplanar and are hinged at 17E and 17F at their remote side edges on stiles 14E and 13E, respectively. The double door operator 191 includes an elongate housing 192 mounted on the stiles 13E and ME, as in FIG. 2. A single door operator unit 20E, arranged as in FIG. 8, is provided at one end of the housing 192, here the rightward end as diagrammatically indicated in broken lines. The door operator 20E is arranged within the housing 192 and opens and closes the door 16E in the same manner above described with respect to FIGS. 2 through 9.

In addition, however, a dislike synchronizing member 198 is fixed to the upper end of the shaft 69E for rotation therewith. In the particular embodiment shown, member 198 is a sprocket. The lower end of the shaft 69E, as in FIG. 8, is connected through links 93E and 94E to the door 60E.

A similar shaft 69F is rotatably supported at the opposite end of housing 192 by suitable bearings not shown, as in FIG. 3. The lower and upper ends of shaft 69F extend beyond the top and bottom walls of the housing 192 and respectively fixedly carry a link 93F (which as in FIG. 2 connects through a further link 94F to door 16F) and a further synchronizing member, or sprocket 199, preferably identical to the member 198. Flexible positive drive elements 201 and 202, here lengths of chain, partially encircle sprockets 198 and 199, respectively and are in positive driving relation therewith. Crossed cables 203 and 204 join the diagonally opposed ends of chains 201 and 202 to provide a closed loop of Figure-eight configuration which is maintained under moderate tension, hereby a turnbuckle l06 in cable 203.

Thus, rotation of shaft 69E by the door operator 20E, by rotation of sprocket 198, orbiting of chains 201, 202 and cables 203, 204 effects equal and opposite rotation of sprocket 199 and hence of shaft 69F. Thus, shafts 69E and 69F rotate in opposite directions and in synchronism to effect a shychronized opening or synchronized closing of their corresponding doors 16E and 16F.

If desired, in cases where for example the doors 16E and 16F are relatively heavy or have relatively high pivot friction, an additional operator, not shown, arranged in a manner of operator 20 of FIG. 2, may be provided at the left end of housing 192 to rotatably drive the shaft 69F for opening and closing door 16F, the synchronizing apparatus 198 through 206 maintaining synchronous opening and closing of the two doors despite the use of two separate operators.

FIGS. 14 and I5 disclose a modification providing for power assisted door closing and usable, for example, in high stack pressure situations wherein the normal springs 66 and 67 (FIG. 3) may be insufficiently strong as to close the door. Such modification can be either factory or field installed.

FIG. 14 discloses a piston rod 56 of cylinder 41 in an intermediate position of door closing movement and is modified from the structure shown in FIGS. 4-6 as follows.

A further solenoid valve assembly 208 comprises a casing 209 containing a chamber 210. A reciprocable valve element 211 is slidable in the chamber 147 to alternatively close an exhaust port 213 (during door closing movement, as shown in FIG. 14) and a pressure fluid inlet port 214 (during door opening movement). The exhaust port 213 may vent directly to the atmosphere. The inlet port 214 connects through an adjustable orifice, or valve 216, control valve 16, and a conduit 217 to the source S of pressurized air, as schematically indicated in FIG. 14. A conduit or passage 219, connects the chamber 210 to the free flow port 108 of cylinder 41, above described, and also to the port 130 of the restrictive orifice unit 124, above described.

FIG. discloses a fragment of the circuit of FIG. 7 modified by the addition of a closing solenoid circuit 221. Such circuit 221 includes a relay RR4 having a winding W4 energizable for opening a single-pole, single-throw switch S4. The winding W4 connects through lines 176A and 162A across the opening solenoid 156 above discussed with respect to FIG. 7. A line 164A connects from AC line 164 through switch S4, a closing solenoid 222 and line 162A to the other AC line 162. The closing solenoid 222 is suitably mechanically connected, as schematically indicated by broken line 223 in FIG. 14, to the valve element 211.

Thus, when the opening solenoid 156 is energized (to open or hold open the door) as above discussed, the winding W4 is similarly energized to open switch S4, whereby closing solenoid 222 is deenergized. When such solenoid is deenergized it locates the valve element 211 in its leftward position (FIG. 14) closing the pressurized air inlet 214 and opening the exhaust port 213. Thus, air pushed ahead of the leftwardly moving (FIG. 14) piston 112 escapes the cylinder 41 through port 108, and to a lesser extent through restrictive orifice unit 124, and thence through passage 219 past the valve element 211 and out exhaust port 213.

On the other hand, when opening solenoid 156 is deenergized so also is winding W4 (FIG. 15) and switch S4 is closed, energizing closing solenoid 222 by connecting same across the AC line 164 and 162. The energized solenoid 222, through the connection 223 (FIG. 14) shifts the valve 211 to its rightward position shown in FIG. 14, closing exhaust port 213 and opening the passage 214. Air then flows from the pressurized source S through conduit 217, at a rate controlled by the speed control valve 216, and thence through port 214 and passage 219 to the port 108 (and to the lesser extent through restrictive orifice unit 124) and thereby into the leftward (FIG. 14) end of the cylinder 41 to assist the springs 66 and 67 (FIG. 3) in extending the piston rod 56, so as to close the door.

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

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

1. In a door operator for a door movable between an opened position and a closed position, the combination comprising:

a flexible endless loop member and door drive shaft means direct driven in opposite directions thereby for opening and closing said door;

motor means engaging a reach of said endless loop member and actuable for moving said endless loop member in one orbital direction;

return means also engaging a reach of said endless loop member and responsive to disabling of said motor means for closing said door through moving said endless loop member in the opposite orbital direction;

whereby said motor means and return means oppositely orbit said endless loop member to move said door between open and closed positions.

2. The apparatus of claim 1 in which said door drive shaft means includes a door drive shaft and a rotatable drive member fixed thereon and including a freely rotatable idler spaced therefrom by said reaches, said flexible endless loop member encircling said idler and drive member and positively engaging and rotatably driving said drive member, said motor means and said return means respectively comprising a pressure fluid cylinder energizable for retraction and a tension spring, each of which has an end directly connected to said endless loop member intermediate said drive member and idler, and means coupling said rotatable drive member to said door for opening and closing same upon opposite orbital movement of said loop member by said cylinder and spring.

3. The apparatus of claim 1 in which said motor means includes a pressure fluid cylinder having a retractable piston rod connected to said endless loop member for moving said door, a piston on said piston rod and responsive to pressure on one side thereof for moving said piston rod in one direction, oppositely directed cam means on said piston rod and chamber means at opposite ends of said cylinder gradually blockable by respective cam means for gradually initially decelerating the piston rod before nearing the ends of its stroke, and valve means controllable for applying pressure fluid to said piston rod to move same in said one direction.

4. The apparatus of claim 3 including first restrictive orifice means paralleling the said chamber means at one end of said cylinder for further decelerating said piston as it approaches said end of said cylinder in the final part of its stroke, valve unit means at the opposite end of said cylinder and a conduit in communication with said valve unit means, said valve unit means including a second restrictive orifice and a one-way valve both connected in parallel between said conduit and said opposite cylinder end, said one-way valve allowing free fluid flow from said conduit to said piston but positively blocking return flow thereby except return flow through said second restrictive orifice, said valve unit means further including a passage communicating between said conduit and the adjacent other said chamber means in parallel with said second restrictive orifice and one-way valve.

5. The apparatus of claim 4 including a pressure fluid source and third restrictive orifice means alternatively communicable with said conduit past said controllable valve means, said controllable valve means including a plunger movable for alternately blocking said source and third restrictive orifice means.

6. The apparatus of claim 1 including electrically energizable means for actuating said motor means, control circuit means responsive to actuation of an actuating switch for energizing said electrically energizable means and for maintaining said energization for a predetermined delay time following the deactuation of said actuating switch.

7. The apparatus of claim 6 including switch means responsive to actuation of a safety switch for causing said control circuit means to hold said door open in response to prior actuation of said actuating switch occurring within said delay time but for preventing opening of said door in response to a subsequent actuation of said actuating switch.

8. The apparatus of claim 1 including a housing supporting said endless loop member, motor means and return means adjacent said door, said door drive shaft means comprising a shaft rotatably supported in said housing and having both ends thereof extending from said housing, means connecting one extended end of said shaft to said door for opening and closing said door upon opposite rotations of said shaft, said door operator being usable with both rightwardly and leftwardly hinged doors by rotation of said housing through 180 about an axis transverse to the plane of the closed door and using of the opposite extended shaft end for opening and closing connection to said door.

9. The apparatus of claim 1 including a housing carrying said endless loop member and motor means and return means, said housing being offset vertically of said door width-wise of the door opening, said motor means including an elongate reciprocable member secured to said endless loop member, said return means comprising an elongate resilient member secured to said endless loop member, said endless loop being longitudinally extended lengthwise of said housing, said reciprocable member and said resilient member end engaging said endless loop member and extending along said reaches and longitudinally of said endless loop member to opposite ends secured to the housing remotely of said endless loop member for urging said reaches of said endless loop member in opposite rotational directions.

10. The apparatus of claim 9 in which said resilient member comprises an elongate tension spring and including bracket means on said housing and spaced from said endless loop member, said resilient member being secured adjacent its free end to said bracket means for rotating said endless loop member when tensioncd and in the absence of actuation of said motor means.

11. The apparatus of claim 10, in which said motor means comprises a pressure fluid retraction cylinder, said reciprocable member comprising the piston rod thereof, said cylinder being located remotely of said endless loop member and including means pivotally mounting the free end of said cylinder on said housing for permitting pivotal movement of said pressure fluid cylinder during retraction of said piston rod. 12 The apparatus of m'ir'rfivmar said bracket means is reversibly mounted on said housing, said pressure fluid cylinder and spring normally extending substantially in parallelism along and beyond opposite reaches of said endless loop member, said reaches extending substantially longitudinally of said housing, whereby said door operator is adaptable to use with either inwardly or outwardly swinging doors by reversal of said bracket means on said housing and pivoting of said pressure fluid cylinder to allow reversed securement of said piston rod and spring to said endless loop means.

IS. The apparatus of claim 12 in which said endless loop member is secured to said spring and piston rod ends on opposite reaches thereof, said door drive shaft means including a rotatable drive member and the shaft thereof rotatably supported on said housing and spaced away from said spring and rod ends, said shaft being driven by said endless loop member directly through said rotatable drive member and fixedly carrying a first link, a second link pivotally engaging said first link and said door, whereby rotation of said shaft results in opening and closing movement of said door, the length of said links being variable for adapting said operator to either inwardly or outwardly swinging doors.

14. The apparatus of claim 1 including a spaced pair of rotatable members around which said endless loop member orbits, said endless loop member being in positive driving engagement with one said rotatable member, a housing disposed directly above said door, said door drive shaft means incorporating said one rotatable member, a shaft fixedly engaging said door on the hinge axis thereof and extending rotatably and upwardly into said housing, said shaft fixedly engaging said one rotatable member, whereby orbiting of said endless loop member opens and 15. The apparatus of claim 1 in which said door is a sliding door, said endless loop member being supported in a substantially vertical plane above said sliding door and including a rotatable idler, said door drive shaft means consisting of a shaft and a rotatable drive member carrying said endless loop member in cooperation with said idler, said endless loop member directly driving said rotatable drive member, a link fixed to said shaft and a substantially vertical guide track on said door slidably engaging said link, whereby rotation of said drive member slides said door between open and closed positions.

16. The apparatus of claim 1 in which said door comprises a pair of substantially alignable door panels hinged at remote side edges thereof, said door operator including a housing adjacent the tops of said door panels, a pair of rotatable synchronizing members on said housing adjacent opposite ends thereof, one said synchronizing member being fixed on said door drive shaft means, an elongated loop twisted to define substantially a figure-eight configuration and passing around said rotatable synchronizing members for constraining said members to rotate in synchronism and in opposite rotational directions, a first operator unit comprising said endless loop extending from said drive shaft means in overlapping relation with said figure-eight loop, said motor means and return means respectively comprising respective powered and resilient elongate retractable members extending from the reaches of said endless loop member below said figure-eight" loop.

17. The apparatus of claim 16 including a second door operator unit of similar kind and reversed orientation having a positive driving connection to the other of said synchronizing members and door panel.

18. The apparatus of claim 5 including a further oneway valve connected in parallel with said third restrictive orifice means to said controllable valve means and oriented to positively block pressure fluid flow therethrough from said controllable valve means but to freely allow fluid flow therethrough toward said controllable valve means, whereby, when said controllable valve means is positioned to block communication between said source and said conduit, and said piston is moving toward said one end of said cylinder, said further one-way valve maintains atmospheric pressure behind said piston.

19. The apparatus of claim 3 including further valve means controllable for applying pressure fluid to said piston rod to move same in said opposite direction for assisting said return means and including a solenoid controlled valve having a valve element shiftable for alternatively allowing exhaust fluid movement out of said cylinder ahead of the piston rod as the latter moves in said one direction for opening the door and for applying pressure fluid to said piston to assist moving same in said opposite direction during door closing movement.

20. The apparatus of claim 19 in which said controllable valve means includes an opening solenoid ener-- gizable for causing pressure fluid to move the piston rod in said one direction and in which said further valve means includes a closing solenoid and a relay for controlling actuation of said closing solenoid, said relay being connected in parallel with said opening solenoid and adapted to energize said closing solenoid in alternative relation to energization of said opening solenoid.

21. The apparatus of claim 19 in which said further valve means includes a speed control valve in series with saidsolenoid controlled valve.

22. The apparatus of claim 9 including pivot means for securing said opposite ends of said reciprocable member and resilient member in said housing and a freely rotatable idler, said endless loop member having extremities rbi allxsupe lsi sais id ctan driv shaft means, said pivot means and door drive shaft means being spaced in opposite directions longitudinally of the housing from said idler, said reciprocable member comprising longitudinally extended linear actuator means actuable for retraction and said resilient member comprising a tension spring, the first mentioned ends of said retractable linear actuator means and spring being fixed to opposite reaches of said endless loop means and extending therealong away from said drive shaft means foralternatively tensioning said loop means around said door drive shaft means.

23. The apparatus of claim 3 including valving means connected to the one of said cylinder ends approached by the piston rod moving in said one direction for controlling fluid flow to and from said one chamber means, a valve unit at the other end of said cylinder, and means defining a flow path between said valving means and said valve unit (1) for traveling fluid to said one cylinder end to facilitate movement of said piston away therefrom in response to urging of said return means and (2) for alternatively traveling fluid to said valve unit at said other cylinder end during piston movement away from said other cylinder end.

24. The apparatus of claim 3 including valving means connected to the one of said cylinder ends approached by the piston rod moving in said one direction for controlling fluid flow to and from the chamber means at said one cylinder end, a valve unit at the other end of said cylinder, and means defining a flow path between said valving means and said valve unit (1) for traveling fluid to said one cylinder end to facilitate movement of said piston away therefrom in response to urging of said return means and (2) for alternatively traveling fluid to said valve unit at said other cylinder end during piston movement away from said other cylinder end.

25. In a door operator for a door movable between an opened position and a closed position, the combination comprising:

endless loop means movable in opposite directions for opening and closing said door;

motor means coupled to said endless loop means and actuable for moving said endless loop means in one direction, said motor means including a pressure fluid cylinder having'a retractable piston rod connected to said endless loop member for moving said door, a piston on said piston rod and responsive to pressure on one side thereof for moving said piston rod in one direction, oppositely directed cam means on said piston rod and chamber means at opposite ends of said cylinder gradually blockable by respective cam means for gradually initially decelerating the piston rod before nearing the ends of its stroke, and valve means controllable for applying pressure fluid to said piston rod to move same in said one direction;

return means coupled to said endless loop means and responsive to disabling of said motor means for moving said endless loop means in the opposite direction;

whereby said motor means and return means act through said endless loop means to move said door between open and closed positions.

26. in a door operator for a door movable between an opened position and a closed position, the combination comprising:

endless loop means movable in opposite directions for opening and closing said door;

motor means coupled to said endless loop means and actuable for moving said endless loop means in one direction;

return means coupled to said endless loop means and responsive to disabling of said motor means for moving said endless loop means in the opposite direction;

electrically energizable means for actuating said motor means, control circuit means responsive to actuation of an actuating switch for energizing said electrically energizable means and for maintaining said energization for a predetermined delay time following the deactuation of said actuating switch, switch means responsive to actuation of a safety switch for causing said control circuit means to hold said door open in response to prior actuation of said actuating switch occurring within said delay time but for preventing opening of said door in response to a subsequent actuation of said actuating switch;

whereby said motor means and return meansact through said endless loop means to move said door betwen open and closed positions.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3 864 875 Dated February 1 1915 a l Lew V. Hewitt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 16, line 21; after "and" insert closes said door.-.

Col. 17, line 3; change "said" to -the.

Col. 17, lines 40 through 51; please cancel Claim 23.. 0 Col. 18, after line 60; add the following claim:

---27. In a door operator, for a door pivotable between I Q an open position and a closed position, the combination comprising:

a housing fixedly mountable above and adjacent said door and extending substantially the width of the door opening;

a drive shaft extending through at least a bottom wall of said housing and rotatably supported on opposed top and bottom housing walls and means connecting said drive shaft to said door at least adjacent a pivot axis of said door for rotating said door between open and closed positions upon rotation of said drive shaft;

a rotatable disklike drive member fixed on said shaft USCOMM-DC 60376-P69 u.s. GOVERNMENT PRINTING orncz; 869 93 0 FORM PO-105O (10-69) UNITED STATES PATENT OFFICE Page 2 CERTH ICATE 0F ;CORRECTION Patent No. 3 864 875 Dated February 11, 1975 Inv nt0 Lew V. Hewitt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. and located in said housing;

a freely rotatable idler fixedly located in said housing remote from said drive member and an endless loop member encircling said drive member and idler in positive and toothed driving connection with said drive member for rotating said shaft synchronously with orbiting of said endless loop member,

a said endless loop member having first and second reaches on opposite sides of a common diametrical line between said idler and said drive member;

a an elongate resilient tension member and means releasably fixedly securing one end thereof to said housing remotely from said endless loop member and means fixedly securing the a other end thereof to one reach of said endless loop member;

a pressure fluid cylinder adjacent said resilient member having a piston rod extending from one end thereof into fixed Q engagement with the other reach of said endless loop member,

FORM PO-1 USCOMM-DC 60376-P69 U.$ GOVERNMENT PRINTING OFFICE: a 9 93 O FORM PO-105D (10-69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Page 3 Patent No. Dated ebruary ll, 1975 Inventor(s) Lew V. Hewitt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

the other end of said cylinder being pivotally supported on said housing, said cylinder including means at the ends thereof incorporating controllable restrictive orifices and coacting means on said piston rod for providing controlled deceleration of said piston rod at the ends of its stroke;

a solenoid controlled valve and a variable time delay control circuit carried by said housing, said solenoid control valve being responsive to said control circuit for alternatively applying pressure fluid to said one end of said pressure fluid cylinder for retracting said piston rod and for exhausing said last-mentioned end of said cylinder at a controlled rate;

switches on opposite sides on said door and means coupling same to said control circuit for opening said door in response to actuation of one said switch, holding said door open for a controlled delay period in response to subsequent actuation of the other said switch within a similar delay USCOMM-DC 60376-P69 U.S GOVERNMENT PRINTING OFFICE: o

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Classifications
U.S. Classification49/115, 49/334, 49/264, 49/360, 49/340
International ClassificationE05F15/02
Cooperative ClassificationE05F15/06, E05Y2900/132, E05F15/04, E05F15/02, E05F17/004
European ClassificationE05F15/02, E05F15/06, E05F15/04
Legal Events
DateCodeEventDescription
Sep 6, 1994ASAssignment
Owner name: OVERHEAD DOOR CORPORATION, TEXAS
Free format text: RELEASE OF SECURITY INTEREST;ASSIGNOR:MANUFACTURERS HANOVER TRUST COMPANY;REEL/FRAME:007118/0378
Effective date: 19940815
Oct 5, 1990ASAssignment
Owner name: MANUFACTURERS HANOVER TRUST COMPANY, NEW YORK
Free format text: SECURITY INTEREST;ASSIGNOR:OVERHEAD DOOR CORPORATION;REEL/FRAME:005475/0554
Effective date: 19900927
Jun 20, 1990ASAssignment
Owner name: MANUFACTURERS HANOVER TRUST COMPANY, NEW YORK
Free format text: SECURITY INTEREST;ASSIGNOR:DALLAS CORPORATION;REEL/FRAME:005328/0070
Effective date: 19900208