Safety actuator apparatus for one-piece overhead garage door operator
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a safety device for mounting on an automatically operated garage door and responsive to engagement with an object to deactuate and reverse an operator. 
     2. Description of the Prior Art 
     The advent of automatic doors actuated by automatic operators has led to the need for pressure sensitive deactuation devices which are responsive to contact with an object located in the door path to deactuate the operator. A number of injuries, and even deaths, have been reported due to the lack of an effective safety actuator for stopping or reversing an automatic operator upon the door making contact with a hapless person passing through the path thereof. 
     Current popularity of overhead garage doors driven by an automatic operator for opening and closing have led to further development of various sensing devices. Many such automatic closures incorporate a pressure sensing arrangement along the lower edge of the door such that upon contact with a vehicle or the like will deactuate the operator to minimize damage to the vehicle or door structure. However, such devices typically suffer the shortcoming that the deactuating devices require application of significant amounts of force thus resulting in the impact of damaging forces to the vehicle before the deactuator becomes fully operative. 
     U.S. Pat. No. 3,001,038 to Gazelle recognized the existence of a need for an automatic deactuator highly responsive to the encountering of an obstruction to halt closure. However, the relatively sophisticated and expensive pistons for carrying the moveable edge has proven unduly expensive to fabricate and does not afford the necessary angular range for application of actuating forces for practical use on a one-piece overhead garage door. 
     Thus, there exists a need for a deactuator which is highly sensitive to contact with an object during closure of the door such that contact with a small child or the like during closure will deactuate the closure to protect the child from injury. The design challenges for such a device are greater for one-piece overhead garage doors since those doors typically close in a manner which swings the free lower end of the door through an arcuate path. This results in contact being made by the lower edge of the door with an obstructing object from any one of a number of different directions throughout a wide range of angles depending on the height of such lower edge at the point of contact. 
     Prior efforts to devise satisfactory deactuation mechanisms have led to the proposal of a symmetrically shaped semicircular hollow deflectable channel member mounted centrally on a door edge and carrying an electrical contact and which will be deflected upon impact to engage a cooperating contact to thereby generate an electrical signal. A device of this type is shown in U.S Pat. No. 1,511,055 to Entwistle. Devices of this type, while satisfactory for their intended uses, suffer the shortcoming that substantial force is required for deflection of the channel and contact with an object at an angle of, for instance, 45° to the plane of the door, typically fails to adequately deflect the channel to make contact and close the circuit. 
     Other efforts to provide a satisfactorily sensitive door edge sensing mechanism has led to the proposal of pneumatic tubes or the like mounted adjacent the door edge for deformation upon contact to increase the pressure in the tube for sensing by a pressure sensitive switch. A device of this type is shown in U.S. Pat. Nos. 3,303,303 and 4,620,072 to Miller. Such devices, while sufficiently sensitive to be actuated upon engagement of the door edge with a forklift vehicle or the like, typically cannot be designed sufficiently sensitive to respond at different temperatures, under a variety of climatic conditions, and with sufficient sensitivity to fully minimize injury to a person contacted thereby. 
     Other solutions have been proposed which incorporate electrically conductive strips spaced apart by means of a compressible insulative strip or the like to create a pressure sensitive switch such that compression thereof permits the contacts to come into engagement with one another to thereby generate an electrical signal. Devices of this type are shown in U.S. Pat. Nos. 2,843,690, 3,133,167, 3,855,733, 4,273,974, 4,349,710, 4,396,814, 4,785,143, 4,908,483 and 4,920,243 to Miller. Devices of this general type have been marketed under the trade designation Miller Edge by Miller Edge, Concord Industrial Park, Concordville, Pa. 19331. Such devices, while satisfactory for commercial installations where cost is not of particular consideration, have limited application for use on the free edge of one-piece garage doors since such devices must be capable of mass production and economical to use. 
     Other efforts to produce a satisfactory device have led to the proposal of spaced apart conductive strips housed in a flexible channel mounted centrally on a door edge and designed with an internal strut work such that forces applied to the channel is intended to act through such struts to press the strips together. Devices of this type are shown in U.S. Pat. No. 3,118,984 to Koenig and U.S. Pat. No. 4,115,952 to French. The cost of such continuous strips is considerable and range of angles from which actuation forces may be applied is limited. 
     Devices have also been proposed which incorporate hollow tubes mounted along the edges of automatic doors for containing pressurized fluid which is responsive to application of forces for deactuating an operator. A device of this is shown in U.S. Pat. No. 4,133,365 to Schleicher. Such devices, while satisfactory for installations where the climatic conditions are constant and substantial forces are not objectionable, suffer the shortcoming that such fluid does not typically operate over wide ranges of temperature variations. 
     Thus, there exists a need for an actuator apparatus for mounting on the lower edge of a one-piece garage door and configured such that application of forces thereto from various different angles as dictated by the point in the path followed by the lower edge during closure at which contact is made with an obstruction to thereby avoid application of excessive forces to the object. 
     SUMMARY OF THE INVENTION 
     The present invention is characterized by an elongated electrically conductive channel mounted from a non-conductive base and formed in cross section with a wall which is, upon contact with an obstruction, deflectable through a predetermined path. Mounted in the interior of the channel and extending throughout the length thereof is an elongated, upstanding conductive strip disposed in the path of the deflectable wall such that deflection of such wall through such path results in contact between such wall and strip to thereby complete a circuit which may be utilized to reverse operation of the door operator. 
     Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a safety actuator embodying the present invention; 
     FIG. 2 is a broken side view, in enlarged scale, taken along the line 2--2 of FIG. 1; 
     FIG. 3 is a partial vertical, sectional view, taken along the line 3--3 of FIG. 2; 
     FIG. 4 is a sectional view, similar to FIG. 3, but showing the safety actuator contacting an object disposed in its path; 
     FIG. 5 is a schematic of the electrical circuit incorporated in the safety actuator shown in FIG. 2; 
     FIG. 6 is a broken rear view similar to FIG. 2 but showing a second embodiment of the safety actuator of the present invention; and 
     FIG. 7 is a schematic depicting the electrical circuit incorporated in the safety actuator shown in FIG. 6. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, the safety actuator apparatus of the present invention includes, generally, an elongated sensor fitting 11 mounted on the interior lower edge of a one-piece overhead garage door 13. The sensor fitting includes an elongated L-shaped base, generally designated 15, constructed of an electrically insulative vinyl compound. Mounting on the face thereof is an elliptical in cross section hollow elongated sensor channel 17 constructed of an electrically conductive vinyl compound. The wall of the sensor channel 17 is deflectable inwardly along its length, such as along a path defined by an extension of the vector arrow 21 shown in FIG. 3. A generally J-shaped in cross section electrical strip, generally designated 25, also constructed of an electrically conductive vinyl compound, is mounted within the chamber defined by the interior of the channel 17 such that it may be engaged by the wall of such channel upon deflection inwardly along the extended path of the vector arrow 21 as shown in FIG. 4 to thus complete a circuit between the wall of such channel and the contact strip device 25. 
     The need for a highly sensitive tactile safety actuator has become of such great concern that various governmental agencies have considered and have, in fact, enacted legislation restricting the sale, installation or repair of automatic door operators which fail to incorporate an effective safety actuation device for sensing and controlling an operator which is normally operative to close a garage door. The problems encountered in designing a safety actuator for a one-piece overhead garage door are somewhat different from that encountered in the design of doors travelling on a linear track, such as a sectional garage door, elevator door, or various industrial doors and common carrier doors. That is, one-piece overhead garage doors are typically mounted from a suspension mechanism, such as the mechanism generally designated 31 in FIG. 1 whereby the bottom edge of the door generally lifts up and translates outwardly and upwardly upon opening and follows a reverse path upon closing. It is of recognized concern that during closure the bottom end of the door follows a somewhat arcuate path travelling downwardly and inwardly toward the door frame. Travel is initially primarily downwardly in a vertical direction concluding with travel in a direction which is primarily horizontal. Thus, the direction from which the lower edge of such door approaches an object during travel throughout its closure path varies progressively from a direction which is primarily vertical to one which is primarily horizontal. Accordingly, the safety actuator of my invention is intended to be responsive to contact with an obstructing object throughout the entire closure path, irrespective of the point in that path at which the object is engaged. 
     The opening and closing of such garage doors is typically compelled by an overhead garage door opener, generally designated 35 (FIG. 1) which is coupled with an arm 37, as by a screw drive or chain, such that a receiver will be responsive to actuation of a remote transmitter to thereby initiate operating and actuate a motor to drive the door to its open or closed position. 
     It is this path of travel during closure of the door that renders relatively fail safe operation of the sensor 11 somewhat difficult. That is, the obstructing object may be encountered at any height from just several inches off the floor to a position disposed five to seven feet above the floor or driveway. Consequently, the lower door edge may be, at the time of impact with an intruding object, travelling through a path which has a primarily vertical component or may, as for instance toward, the completion of its closure path, have a primarily horizontal component, or during any intermediate portion of that path, a combination of horizontal and vertical components that is generally varying with the height of the lower door edge. It will be appreciated that with this construction, a generally conventional pressure sensitive contact strip arrangement mounted directly on the bottom edge of the door will be of little usefulness during that portion of the closure path when the door is travelling primarily in the vertical travel direction. Thus, the deactivating sensor device 11 is preferably mounted such that the sensor channel 17 projects from the inner face of the door at the lower margin thereof. 
     Electrically conductive vinyl compounds have long been known in the marketplace for various applications and one such supplier for the compound utilized in the preferred embodiment is Product No. A100-1 from Teknor Apex Company, 505 Central Avenue, Pawtucket, R.I. The compound may be extruded in a manner known to those skilled in the art such that the L-shaped base 15 (FIG. 3) of non-conductive compound may be extruded integral with the channel 17 and, if desirable, the conductive strip device 25. The extruded sensor device 11 may thus be supplied in strip form and cut to the desired length. 
     The base 15 is preferably L-shaped to cap the inner lower corner of the door and embrace the lower interior margin of the door and bottom edge thereof. The channel 17 is preferably of a generally elliptical cross sectional shape to define a deflectable nose which, in response to rather minor forces, as represented by the vector arrow 21, will readily deflect inwardly. 
     The contact device 25 may be in the form of a single strip or, as shown in the preferred combination, may be somewhat in the form of the letter J to define a main leg 41 projecting perpendicular to the face of the door 13 and a minor leg 43 angling generally downwardly and outwardly approximately 45° to the face of such door. Thus deflection of the wall of the channel 17 near the base resulting from contact with an object from a somewhat oblique direction will serve to make contact with the minor leg 43 while contact of the apex thereof during initial downward travel will serve to deflect such apex to make contact with the tip end of the major leg 41. 
     Referring to FIGS. 1 and 2, the operator 35 incorporates a switch (not shown) operative in response to an electrical signal to deactuate the operator. The terminals of that switch are connected with the sensor channel 17 and contact device 25 by means of respective electrical cables 45 and 47. Referring to FIG. 2 in the embodiment shown for illustrative purposes, one such terminal is connected to the distal end of the sensor channel 17 by means of the lead 45 and the opposite such terminal is connected with the proximal end of the contact device 41 by means of the cable 47. It will be appreciated by those skilled in the art that the invention may be incorporated in numerous different embodiments including those having such cables both connected at the same end of such sensor device 11. 
     Referring to FIG. 5, the reversible motor 51 of the operator 35 is connected with a logic board 53 which acts as a reverse switching mechanism, the sensor device 11 and up and down limit switches, generally designated 57 and 59, respectively. In the embodiment shown, the lead cables 45 and 47 incorporate the safety feature afforded by dual leads. 
     In operation, the sensor device 11, cables 45 and 47, operator 35, and logic board 53 will typically be marketed packaged together and the installer may merely unpackage the components and install the operator in a conventional manner. The sensor device 11 may then be installed on the inside lower edge of the door 13 and the cable 45 threaded through the hollow interior of the to connect the end thereof with the distal end to maintain good electrical contact. The cable 47 may then be connected with the proximal end of the sensor device 25 as shown in FIG. 2. 
     Then, upon operation, the door may be opened and closed in a conventional manner. However, should the sensor device 11 come into contact with an intruding object during closure thereof, the wall of such channel 17 will be deflected inwardly, as for instance along the vector path 21, to engage either or both the contact legs 43 or 41. As shown in FIG. 4, in the event contact is made with the minor leg 43, the circuit will be closed, thus switching the logic board 53 to reverse the circuit to the motor 51 to reverse travel of the door. In practice, the flexure of the wall of the channel 17 is such that even the lightest contact with a relatively vulnerable body part, such as a child&#39;s neck, will be sufficient to deflect such wall sufficiently to short against the contact device 25, all in response to a force well within the range which will avoid injury to a child&#39;s arm, hand or neck. Thus, the sensor device of the present invention provides a effective and safe arrangement for deactuating an automatic door opener before a person disposed in the path thereof might be subjected to injury. 
     The safety actuator sensor device shown in FIGS. 6 and 7 is somewhat similar to that shown in FIGS. 2 and 5 except that a shunt resistor 61 is connected between the sensor channel 17 and contact device 25 to thereby provide a normally closed circuit. The remote end of the sensor channel 17 is then connected with the logic board 53 by means of a lead 65 (FIG. 7) and the contact device 25 connected therewith by means of a lead 67. Accordingly, when contact is made between the wall of the sensor channel 17 and contact device 25, a current path is set up parallel to the shunt resistor 61 to thereby provide an overall reduced resistance which will be sensed in the logic board 53 to reverse the motor 51 of the operator 35. 
     From the foregoing, it will be apparent that the sensor device of the present invention provides an economical and reliable means for sensing the existence of an intruding object in the path of a one-piece overhead door during closure thereof and which is responsive thereto to reverse an automatic garage door operator. 
     Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention.