US 3754176 A
For an electrically powered door having a safety edge, an electric circuit including at least a pair of normally spaced conductor strips resiliently deflectable into engagement with each other by an obstruction in the path of door movement, the contact strips being connected in series, and relay means connected in series with the contact strips having normally closed contacts connected in circuit with the door powering means, so that engagement of the strips operates the relay to prevent further powering of the door in its closing direction.
Description (OCR text may contain errors)
United States Patent [1 1 Miller Aug. 21, 1973 1 ELECTRIC CIRCUIT FOR A SAFETY DOOR EDGE  Inventor: Norman K. Miller, Concordville, Pa.  Assignee: Miller Brothers, Concordville, Pa.  Filed: May 26, 1972 21 Appl. No.: 257,311
Related U.S. Application Data  Continuation-in-part of Ser. No. 166,782, July 28,
 U.S. Cl 318/266, ZOO/61.43, 307/119  Int. Cl. 02p 1/22  Field of Search 307/119; 318/266;
 References Cited UNITED STATES PATENTS 3,651,332
3/1972 Cochran 307/119 3,693,026 9/1972 Miller 307/119 3,315,050 4/1967 Miller ZOO/61.43 3,462,885 8/1969 Miller ZOO/61.43 X
Primary ExaminerB. Dobeck Attorney-Robert K. Youtie s7 1 ABSTRACT 7 Claims, 1 Drawing Figure ELECTRIC CIRCUIT FOR A SAFETY DOOR EDGE CROSS-REFERENCES TO RELATED APPLICATIONS BACKGROUND OFTHE INVENTION As is well known to those versed in the art, there have, in the past, been proposed a wide variety of safety edges for doors, movable walls, curtains or the like, and such devices have been generally effective. However, in the past it has been considered of'major importance that the door or closure not be disabled or rendered inoperative by damage to the safety edge, while it is now appreciated, for many purposes, that the immediate disabling of a door, curtain or the like under damaging conditions is advantageous. Further, it has been found under certain circumstances that the possibility of door operation in damaged or defective condition is advantageously rather difficult, to insure prompt repair of the damage.
Further, it is now recognized that prompt and immediate stopping of a closure upon its engaging an obstruction is desirable and important, but also advantageous is prompt reversing of closure movement, say to release an engaged obstruction. However, such prompt stopping and reversing has been found extremely difficult to obtain, and when obtainable has been found to result in. excessive strain, wear and damage to operating components.
SUMMARY OF THE INVENTION It is, therefore, an important object of the present invention to provide electrical circuitry for use in safety edges for doors and the like wherein defects or damage to the safety edge are not concealed by operating conditions, but rather, cause difficulty in operation of the door to stimulate prompt repair and adequate maintenance.
It is another object of the present invention to provide electrical circuitry for use in safety edges for doors and; the like wherein prompt stopping of the controlled door is. achieved immediately upon the door engaging an. obstruction, and further, wherein quick reversal of door movement follows stoppage by a unique electrical system which is automatic and foolproof in operation and minimizes or relieves strain on the working parts.
It is a. further object of the present invention to provide an. electric circuit for a safety edge of a powered door which, upon damage to'the safety edge, may only be opened, such opening being automatic if desired, but cannot be closed except by manually controlled operation by an operator having visual accessto the door.
It. is a more particular object of the present invention to provide electrical circuitry for a safety door edge having the advantageous.characteristics mentioned in theforegoing paragraphs, wherein normal circuitry operation; may be indicated by a continuous indicator, and. wherein the above described advantages may be achievedin conjunction with a variety of safety edge constructions having different operating characteristics and safety features- Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure. i
The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the socpe will be indicated by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS The single FIGURE of the drawings shows a safety edge construction of the present invention ssociated with a powered door and illustrating the schematic circuitry thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the FIGURE of the drawing, a door, closure, curtain or the like is there generally designated 12, and provided with a safety edge construction 15, which includes an inner pair of contact strips 19 and 20, and an outer pair of contact strips 24 and 25.
As disclosed in greater deetail in my copending patent application Ser. No. 134,809 filed Apr. 16, 1971 and entitled SAFETY EDGE CONSTRUCTION FOR A POWERED DOOR, the contact strips 19, 20, 24 and 25 may advantageously be of aluminum foil or other freely flexible electrically conductive material, suitably mounted and maintained in parallel spaced, facing relationship, as by interposed members or spacers 21, which may be of resiliently compressible material, such as synthetic foam, permitting of deflection by facing spaced adjacent pairs of contact strips into engagement with each other upon the safety edge 15 engaging an obstruction in the path of movement of the door 12.
The inner contact strips 19 and 20 are connected in series, having one pair of adjacent ends connected together by a conductor 28. Similarly the outer pair of contact strips 24 and 25 have one adjacent pair of ends connected together, as by a conductor 29, so as to be connected in series. Further, the two pairs of conductor strips are connected in series with each other, as by a conductor 30 connected between the other adjacent pair of ends of contact strips 20 and 24. A stop relay coil 31 is electrically connected in the conductor 29, and a reverse relay coil 32 is electrically connected in the conductor 28. The other ends of contact strips 19 and 25 are connected together through a resistor 33 and coil 34 of transformer 35. Thus, as will appear more fully hereinafter, power is delivered to the edge circuitry of door 12 from the secondary coil 34 of transformer 35 through an appropriate resistor 33.
Power lines are designated 38, 39 and 40, such as a three-wire power system, being connected toa prime mover or three phase reversible drive motor 41 through overload breakers 42 and 43. Interposed in each supply line 38, 39 and 40 are respective pairs of relay contacts 44, 45 and 46, connected to move a door or closure in one direction, say up or open, upon closing.
Reversing conductors 47, 48 and 49 are connected to supply lines 38, 39 and 40 in a manner to reverse supply c'urrent to the motor 41 when the open relay contacts 44-46 are open. Thus, the motor 41 will operate through reversing conductors 47-49 in the reverse or closing direction. Connected in the reversing conductors 47, 48 and 49 are respective pairs of normally open relay contacts 50, 51 and 52, which upon closing, when the relay contacts 44-46 are open, serve to pass current reversely through the motor 41 for effecting reverse rotation and door movement. The open relay contact 44-46 and closed relay contacts 50-52 are connected to relay coils in a manner appearing presently.
A transformer 55 has its primary 56 connected across supply lines 38 and 40, and its secondary 57 connected in a conductor 58. Also connected in the conductor 58, say at spaced physical locations for convenience of operation, are a pair of normally closed stop switches 59 and 60. That is, the switches 59 and 60 are connected in series with each other and with the secondary transformer coil 57. Further connected in series with the switches 59 and 60 and coil 57 in the conductor 58 may be a protective fuse 61 and an interlock switch 62.
The transfonner 35 has its primary side 65 connected in a conductor 66 across the conductor 58, as by conductors 67 connected to on side of transformer coil 57, and conductor 68 connected to one side of interlock switch 62.
A conductor 70 is connected to the conductor 67 and a conductor 71 is connected to the conductor 68, while an open circuit conductor 72 is connected between the conductor 70 and 71, and a closed circuit conductor 73 is similarly connected between the conductor 70 and 71, in parallel with the conductor 72.
Connected in the open circuit conductor 72 are a pair of parallel connected, selectively or manually operable door open switches 74 and 75. The door open switches 74 and 75 may be located at remote locations for convenience. Connected in parallel with the parallel door open switches 74 and 75 are open switch contacts 76, while an open limit switch 77 is connected in series with the switches 74 and 75, and contacts 76. In series with the open limit switch 77 is an open relay coil 78. The conductor 71 may be provided with overload breakers 79.
In the the door close conductor 73, there is connected a close limit switch 80. Also connected in the door close conductor 43 are a pair of parallel selectively or manually actuable, normally open door close switches 81 and 82. In parallel with the door close switches 81 and 82 are close switch contacts 83. In series with the parallel connected switches 81 and 82, and close switch contacts 83, are normally closed stop relay contacts 84, and also in series with the latter is a close relay coil 85. In parallel or bypassing relation with the stop relay contacts 84 may be an emergency close switch 86. Also, normally open reverse relay contacts 87 may be connected in a conductor 88 between the parallel open and closed conductors 72 and 73. More specifically, the reverse relay contacts are connected between conductors 72 and 73 so as to pass current, when closed, through the open and close limit switches 77 and 80. and the open relay coil 78.
The stop and reverse relay coils 31 and 32 respectively control the stop and reverse relay contacts 84 and 87. Further, the open and close relay coils 78 and 85 respectively control the open and close relay contacts 44-46 and 50-52.
In the illustrated condition the circuit is not energized. However, when voltage is applied to the supply lines 38, 39 and 40, voltage is applied through transformer 55 to the switch circuitry, and through transformer 35 to the safety edge 12. The transformer 35 is protected from direct short by the resistor 33 when both pairs of contacts or strips 19, 20 and 24, 25 are closed.
The application of power energizes stop and reverse relay coils 31 and 32, which causes stop relay contacts 84 to close and reverse relay contacts 87 to open. The circuit is in this condition for normal operation, the interlock switch 62 being closed when the control box cover is closed.
In the illustrated position, the door or closure being controlled is open. Depressing the close button 81 or 82 causes current to flow through now closed stop relay contacts 84 to close relay coil 85. When close relay coil 85 is energized, close switch contacts 83 close and keep close relay coil 85 energized when manual close switch is released. Close relay coil 85 closes close switch con-- tact 50-52 and the controlled door closes until the close limit switch 80 opens. This de-energizes close relay coil 85 and the controlled door stops. When the door is closed the open limit switch 77 is closed. The door can now be opened by depressing the open switch 74 or 75.
Closure of the open switch 74, causes current to flow through'the closed open limit switch 77 to open relay coil 78, energization of the latter serving to close open switch contacts 76 and keep the coil energized when the switch 74, 75 is released. In this condition, the open relay contacts 4446 are closed by the energized open relay coil 78 and the motor'4l operates to open the door 12 until the open limit switch 77 opens. This de-energizes open relay coil 78 and the door stops.
In an emergency, the door can be stopped at any time by depressing one of the stop switches 59, 60, which de-energizes both the open and closed relay coils 78 and 8S.
Should the safety edge 15 become inoperative or improperly operative, as by broken or worn contact strips 19, 20, 24 and 25, the stop relay coil 31 will be deenergized, to open the stop relay contacts 84, to prevent the door from being closed. However, in an emergency the open stop relay contacts 84 may be bypassed by switch- 86 to effect door closing movement, however, continuous manual operation in this manner is required until the damage is repaired, a forceful incentive to obtain repair.
In the event that the door or closure 12 be closing and the safety edge 15 engage an obstruction, the lower or outer contacts 24 and 25 will contact with each other and de-energize the stop relay coil 31 to open the stop relay contacts and cause the door to stop. Should the door system have sufficient momentum to cause further closing movement, the upper or inner contacts 19 and 20 will engege or close to de-energize the reverse relay coil 32 and close reverse relay contacts 87. This causes the open relay coil 78 to be energized and the door 12 will open, thus preventing damage to the obstacle engaged and the door system.
Upon closing against a threshold or door jamb, should the close limit switch fail, the lower or outer contact strips 24 and 25 will engage to de-energize the stop relay coil 31, so that the door will not be damaged.
If desired, an indication of fault or damage to one of the contact strips 19, 20, 24 or 25, there may be provided an indicator, say a lamp, connected in series with either or both of the relay coils 31 and 32, so that nonillumination of the lamp will indicate a damaged safety edge requiring manual control.
From the foregoing, it is seen that the present invention provides electrical circuitry for power door safety edge structures which is extremely safe in assuring immediate stopping of the door closing movement in the event of damage or an obstruction in the door path, permits of manual emergency operation when required as well as affording a continuous indication of proper circuit operation, and which otherwise fully accomplishes its intended objects.
Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of th invention.
What is claimed is:
1. In a safety edge construction for an electrically powered door or the like, an electric circuit comprising at least three resiliently yieldably spaced flexible contact strips defining at least two strip pairs adapted to be deflected into respective successive contact by an obstruction in the path of door movement, conductor means connecting said strips in series with each other across a source of electric supply, and a pair of relays each having its coil connected in a respective strip pair and having contacts in circuit with door powering means, the contacts of one relay connected in the first deflected strip pair being closed when its coil is energized by normal operating circuit through these strips for maintaining the door powering circuit normally enabled, said one relay contacts operating upon contact of said first deflected strip pair to disable the powering circuit, the contacts of the other relay connected in the second deflected strip pair being independent of said one relay contacts and operative to reversely power the door, said other relay contacts being open when its coil is energized by normal operating current through the strips and closed upon contact of said second deflected strip pair to effect reverse powering of the door, whereby contact between said first deflected strip pair shunts said one relay to open its contacts and disable said door powering means, serverance of one of said contact strips precluding the normal operation of said one relay and requiring repair to effect nonnal operation and contact between said second deflected strip pair shunting said other relay coil to close its contacts and effect reverse powering to the door.
2. An electric circuit according to claim 1, in combination with indicator means in series with said strips indicating the continuity of the strip circuit.
3. An electric circuit according to claim 1, in combination with a manual emergency switch electrically connected to selectively by-pass said one relay contacts and effect manually controlled closing of a door having a defective contact strip, said emergency switch being located within sight of the door to insure a clear path of door movement.
4. An electric circuit according to claim 1, said first mentioned relay having its coil connected across one adjacent pair of said contact strips.
5. An electric circuit according to claim 4, said additional relay having its coil connected across another adjacent pair of said contact strips.
6. An electric circuit according to claim 5, in combination with first switch means in series with said one relay contacts for selectively operating the door in one direction, and second switch means in parallelism with said other relay contacts for selectively reversing current to operate the door in the other direction.
7. ,An electric circuit according to a'airfi's, said contact strips comprising two pairs, said one relay having its coil connected between one of said pairs, and said other relay having its coil connected between the other of said pairs.