Patent Publication Number: US-6209264-B1

Title: Device for supporting and moving a door in a multitude of positions

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a device for opening and closing a door and more specifically, this invention relates to a device to effect multiple movements of a suspended door leaf. 
     2. Background of the Invention 
     In an overwhelming majority of situations, a door is opened and closed by hinges along the longitudinal edge of the door. This arrangement has unavoidable disadvantages. Specifically, as the door swings open or shut, the area included in a circular section, the radius of which is equal to the width of the door, must be free of all encumbrances. Longitudinally-hinged configurations also bring problems when thick doors are utilized, inasmuch as thicknesses have to be limited so as to allow clearance of the door edge with the door jamb. This disadvantage is most serious in such situations (shielding of radio frequency radiation or magnetic fields in particular) where one must ensure intimate and continuous contact between the door leaf and the walls of the enclosure or when the door leaf must bear some attachments or equipment that increase the effective thickness of the leaf. 
     Anechoic chambers are another case in point: the walls of the enclosure, the door leaf included, are covered with cones that normally project inwardly toward the center of the enclosure to distances of one meter or more. The use of much larger cones also is not unusual. Such protrusions makes the use of a door leaf extremely difficult to incorporate in a hinged door arrangement. To overcome this shortcoming, a regular thickness door is employed to initially seal the chamber, but then the door is covered with an absorber trolley containing the inwardly directed cones. As such, providing a door with anechoic surfaces requires two actions, first closing the door and then rolling the trolley in position. The same operation, in reverse, is required when exiting the anechoic room through the door opening. 
     Hinged door configurations suffer from other drawbacks. Specifically, where the axis of rotation defined by the hinges is vertical, the center of gravity of the door leaf is at some distance from that axis and thus the weight of the door produces a torque that must be counteracted by the hinges. This torque results in a gradual strain on the hinges with concomitant wear and tear of the hinges and misalignment of the door leaf. Also, because of the relatively large momentum of inertia of the edge-supported door leaf around the axis of rotation, motor-effected opening and closing of the leaf is often most cumbersome and expensive. 
     Finally, hinge-secured door leafs have the further disadvantage that they cannot be moved fully away from the door opening to allow adequate access to the door frame and surrounding elements of the enclosure wall. Examples of hinge secured door leafs include U.S. Pat. Nos. 4,486,980; 4,561,209; 4,953,324; and 5,013,869. 
     Several attempts have been made to overcome the aforementioned disadvantages in hinge-supported vertical door leafs. One method involves suspending the door from one or more wheels or glides. The wheels or glides are allowed to roll or slide on a horizontal rail to facilitate opening or closing the door. However, this configuration allows motion in only one rectilinear direction, which is perpendicular to the door opening, such movement indeed necessary when the leaf is particularly thick. 
     Other door configurations include a door leaf suspended from wheels that roll on a curved channel to impart door rotation around a vertical axis as the door is opened or closed. These arrangements suffer from the same disadvantages as hinge-supported doors, particularly when the leaf is more than a certain thickness. 
     Generally, motion in two rectilinear dimensions has proven to be much more difficult to effect, with multiple sets of rails, wheels or glides required. Heretofore, such arrangements have proven cumbersome especially when one seeks motorized transport of the door leaf inasmuch as two motors and/or a complex shifting mechanism are needed. (See e.g. U.S. Pat. No. 4,691, 581 and U.S. Pat. No. 4,753, 038. In the &#39;038 patent, a door leaf is suspended from a rail which is in turn suspended from a perpendicular rail. The &#39;038 patent requires that the door leaf pivot around a vertical axis and be supported by floor-mounted supports). 
     Systems, such as the ones discussed above where the door leaf is transported on ground-mounted rails have the additional disadvantage that additional supports must be provided to vertically maintain the door leaf. Also, ground mounted hardware, such as rails, impede access to the door and suffer damage as equipment is rolled over them. U.S. Pat. Nos. 4,644,690 and 4,753,038 disclose doors rolling on floor-mounted rails. 
     Two-dimensional or “dual movement” door motion is often required to effect unimpeded access to the door opening, particularly when “bulky” door configurations are utilized, such as in MRI- and Anechoic-applications. 
     A need exists in the art for a simple device to support and transport a door leaf in a plurality of positions. The configuration should be capable of multiple positioning of the leaf when a single channel, a single drive, and a single motor are utilized. The configuration should be particularly accommodating for heavy doors and bulky door designs, such as those incorporating thick dimensions in anechoic applications or movable panels for electromagnetic radiation shielding. The device should also be able to rely on only one means for positioning the door relative to an opening defined by a door jamb. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a device for supporting and moving a door in a plurality of positions that overcomes the disadvantages of the prior art. 
     A further object of the invention is to provide a device for a multi-action door leaf. A feature of the present invention is the suspension of a door leaf on rails to allow the leaf to slide perpendicularly relative to a plane defined by a door frame in an enclosure. Another feature is that these same rails are mounted on a carriage which slides over rails parallel to the plane. An advantage of the present invention is that the door leaf moves perpendicular to the door frame and then parallel to the door frame in one continuous motion. Another advantage is that the device accommodates the opening and closing of door leafs integrally formed with anechoic surfaces so that the establishment of an anechoic surface at an opening defining the door jamb is made simultaneously with the door engaging with the door jamb. As such, no need for a separate absorber trolley in conjunction with the door operation is necessary. 
     Another object of the invention is to provide a device for a dual movement door leaf that employs a single motor. A feature of the present invention is that a single motor removes a door leaf from its jamb using over-head rails by first sliding the leaf perpendicularly from the plane of the wall of an enclosure and then secondly laterally sliding the door leaf parallel to the plane of the wall and away from the door opening. An advantage of the present invention is that a single motor effects the door leaf motion perpendicular to the wall when the door is first opened and then parallel to the wall and conversely when the door is closed. Another advantage is that no floor mounted hardware is required, thereby providing a smooth threshold. 
     Yet a further object of the invention is to provide a device for maintaining and moving a door in a multitude of positions that employs a single channel and drive chain. A feature of the present invention is that the door leaf is transported by a single motor that engages the longitudinal axis of a single continuous path which deviates by as much as 90 degrees. An advantage of the present invention is that a single motor driven along a continuous drive chain effects door leaf motion in a myriad of directions. 
     Still another object of the invention is to provide a device for a dual movement door leaf that places minimal stress on the motor and drive chain. A feature of the present invention is that door leaf is suspended from rails that allow the leaf to slide perpendicularly to the plane of the wall of an enclosure while these rails are mounted on a carriage that is free to slide over rails parallel to the plane of the wall. An advantage of the present invention is that weight of the door leaf is not supported by the motor and drive mechanism, thereby minimizing warping and wear and tear of the motor and drive mechanism. 
     In brief, the invention provides a multi-action door mechanism comprising a door leaf defining a plane; and a single motor attached to said door leaf so as to cause said leaf to move in a multitude of directions relative to the plane. 
     Also provided is a double-action door comprising a door leaf; a door jamb adapted to receive said door leaf, said doorjamb defining a plane; and a motor attached to said leaf so as to cause said leaf to disengage from said jamb by first moving said leaf perpendicular to the plane and then moving said leaf parallel to the plane. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the embodiment of the invention illustrated in the drawing, wherein: 
     FIG. 1 is a perspective view of an exemplary embodiment of the device, in accordance with features of the present invention; 
     FIG. 2 is a perspective view of motor and leaf-actuating system of the device, in accordance with features of the invention; 
     FIG. 3 is a detailed view of the leaf-actuating, motor mount assembly; 
     FIG. 4 is a view of FIG. 3 taken along line  4 — 4 ; 
     FIG. 5 gives an overall view of the door latching mechanism; 
     FIG. 6 is a view of FIG. 5 taken along line  6 — 6 ; 
     FIG. 7 is a view of FIG. 6 taken along line  7 — 7 ; and 
     FIG. 8 is a view of FIG. 5 taken along line  8 — 8 . 
    
    
     DETAILED DESCRIPTION 
     The present invention provides a device for supporting and moving from above a door leaf wherein a single channel, a single motor, and a single drive acting on a single drive chain are utilized to move the leaf perpendicular to the door opening and also parallel thereto. The single drive can be actuated in a myriad of ways, including, but not limited to electrical actuation and pneumatic actuation. 
     While the movement from perpendicular motion to parallel motion is continuous, the movement also can be interrupted anywhere along the arc defined by right angle which defines the extremes of the door leaf movement. 
     Overall Design 
     FIG. 1 provides an overall view of the manner in which a door leaf is supported and transported according to the present invention. The sliding door mechanism is referenced by the numeral  10 . A door leaf  12 , having a first surface  13  and a second surface  15 , is shown in the position where the door leaf covers an opening (not shown) in the wall  14  of the enclosure  16 . The door leaf  12  is suspended from a carriage  18  by means of vertical support (i.e. hanging) bracket assemblies  20  and secondary stabilization brackets  22 , with both types of brackets attached to the door leaf by means of door-mounted brackets  24 . The support brackets  20  and the secondary stabilization brackets  22  rest on glides  26  adapted to slide on a first set of rails  28 . The first rails  28  extend in a direction that is generally perpendicular to the door leaf  12  so as to allow the door leaf  12  to slide in a direction generally perpendicular to the wall  14 . The carriage  18  is slidably positioned on a second set of rails  30  that are parallel to the surface of the wall  14  of the enclosure  16 . Movement of the carriage  18  on the rails  30  facilitates lateral movement of the door leaf  12 , i.e. in a direction generally parallel to the plane of the leaf  12 . These second set of rails  30  are anchored to a manifold of suitable beams that is itself anchored to the wall  14  or freely standing on the floor. 
     Movement of the door leaf may be effected either manually or by means of a motorized assembly that is mounted on the first surface  13  of the door leaf  12 , whereby the first surface directly opposes the carriage  18  and the rail assemblies  28  and  30 . A suitable (e.g. 3 phase, 0.3 kW) motor  34  rotates a sprocket  36  that engages a complementary surface  38  mounted upon a channel  40 . While generally elongate, the longitudinal axis of the channel  40  deviates in a predetermined configuration. In the embodiment shown, the channel  40  effects a right angle bend  42  where it is intended for the door leaf  12  to begin altering its perpendicular direction of motion to a parallel direction of motion relative to the plane defined the door leaf. The channel  40  is anchored to the wall  14  at a point above the door opening and/or to the manifold supporting the second set of rails  30 . The action of the sprocket  36  advancing along the complimentary surface  38  provides the generally perpendicular and parallel motion of the door leaf as discussed above. 
     FIG. 1 also depicts a latching assembly  21  for latching the door leaf  12  in place as well as a safety/escape system assembly  11 . 
     Door Suspension Mechanism. 
     A salient feature of the invention is that the door leaf is suspended from above without the need for floor mounted hardware. The orthogonal configuration of the carriage  18  allows very accurate and reproducible movement of the door leaf, vertically as well as horizontally. A first set of surfaces  17  of the carriage  18  is provided to extend perpendicular to the plane defined by the wall  16 . These first set of surfaces  17  support a first set of rails  28  extending coaxially therewith. A second set of surfaces  19 , extending in a generally parallel direction relative to the enclosure wall  16 , slidably receives the second set of rails  30 . The second set of rails  30  are supported on an immovable substrate  31  which extends parallel to the plane defined by the enclosure walls FIG. 2 shows a detailed view of the door suspension mechanism. 
     The vertical support brackets  20  and the secondary brackets  22  are attached to the glides  26  so as to allow the brackets to slidably communicate with the first rail set  28 . While two rails are illustrated, other rails can be added or just one rail may be utilized, depending on the weight or size of the leaf or panel to be moved. The rails  28  are mounted on the carriage  18  which itself moves in tandem with the leaf  12 . The vertical support brackets  20  are each affixed to a door-mounted bracket  24  by means comprising a Clevis mount  48  and a vertical member  23 . The stabilization brackets  22  communicate with a door-mounted bracket  24  (see FIG. 1) via an elongated member comprising a rod, threadably received by a turnbuckle  46 . The elongated member, positioned so as to generally form an upwardly directed, ever widening acute angle relative to the door, is terminated at each end with a Clevis mount  48  to facilitate hingeable attachment of the elongated member to the stabilization bracket  22  and the door-mounted bracket  24 . The turnbuckles  46  allow adjustment of the load of the door leaf  12  supported by the stabilization brackets and thus ensure proper vertical orientation of the door leaf and minimal load and stress on the motor  34  and motor assembly. 
     A variety of means may be employed to effect the sliding movement of the door leaf on the rails and in and out of engagement of its door frame. For example, wheels mounted on the brackets  20  and  22  and allowed to roll on tracks designed to receive such wheels constitute an alternative to the glides  26 , especially for a massive door leaf. The glides  26  illustrated in FIG. 2 conform very precisely to the cross-section of the rails  28 ,  30 , thus maximizing the area of contact between the glides and the rails in both lateral and in both vertical directions. Thus the glides  26  confer the advantage of limiting wobble and swaying of the door leaf and ensuring that the door leaf will not seek to overshoot past the bend  42  in the channel  40 . Moreover, the glides  26  may be supplemented with roller bearings if less friction is desired, and such friction may be made adjustable by installing screw-adjustable brakes on the glides. 
     Motor Suspension and Drive Mechanism. 
     The method for suspending the motor  34  and transporting the door leaf  12  is illustrated in FIGS. 2 and 3. As noted supra, the instant configuration is unique inasmuch as the door leaf  12  is activated from complete door closure to complete door clearance by a single motor acting on a single drive path, such as a chain configured to a predetermined shape. The drive sprocket  36  is energized by the motor  34  and is engaged by and acts upon the complimentary surface (e.g., a drive chain)  38  mounted in the channel  40 . Thus, when a predetermined voltage is applied to the motor, the sprocket  36  acts upon the complimentary surface  38  with the resulting reaction causing the entire door leaf to either engage or disengage with the door frame. A voltage of the opposite polarity causes leaf movement in the opposite direction. A pinch roller  50  situated so as to confine a portion of the channel  40  between the sprocket  36  and the roller, allows for stable contact between the drive sprocket  36  and the complementary surface  38 . 
     As shown in FIG. 3, the motor  34  itself is mounted on a hinge assembly  52 . This hinge assembly  52  allows the sprocket  36  to negotiate the curve at the channel bend  42  while the pinch roller  50  biases the sprocket to mesh with complementary surface  38  contained in the channel  40 . Also, the hinge assembly  52  allows the motor to be decoupled from the track in emergencies or whenever necessary. The door leaf also may be actuated manually once the motor is decoupled. 
     As shown in greater detail in FIGS. 3 and 4, the motor  34  communicates with the drive sprocket  36  via a rotatable motor shaft  54 . The motor  34  is attached to a mounting generally designated as  55 . The mounting  55  comprises a platform  56  and a lag plate  58  formed at a right angle so that two portions of the lag plate form two planes that are at 90 degrees from each other. A first laterally extending portion  60  of the lag plate slidably communicates with the platform  56  in a direction perpendicular to the door leaf and via an adjacently disposed interaction between a linear carriage  62  and a linear way  64 . The linear carriage  62  is attached to a depending surface  61  of the lag plate while the linear way is attached to the platform  56 . This slidable feature accommodates closure of a door leaf for a variety of leaf thicknesses, jamb thicknesses, and door-jamb contact requirements. An end stop plate  72  limits the sliding motion. 
     An inwardly (i.e. medially) facing surface  68  of the upwardly extending portion  66  of the lag plate  58  directly supports the motor  34 , while an opposing (laterally) facing surface  70  supports the pinch roller  50 . 
     This motor-pinch roller mounting configuration facilitates the positioning of the channel  40  intermediate to the roller  50  and the motor  34 , as discussed supra. 
     To maximize contact of the sprocket  36  to the complementary surface  38  in the channel  40 , particularly when the channel changes direction, the mounting  55  further comprises a means for laterally varying the position of the motor  34  vis-a-vis the longitudinal axis of the channel  40 . This lateral varying means comprises a hinge  74  (FIG. 3) having its longitudinal axis parallel to the door leaf  12 . A first side  76  of the to hinge, proximal to the door leaf  12  is attached to an upwardly extending portion  78  of the platform  56 , while a second side  80  of the hinge, distal to the door leaf, is attached to an upwardly extending portion  82  of a platform resting surface  84 . 
     Motor Decouplina Mechanism 
     To facilitate manual operation of the door, also provided is a means for decoupling the door-leaf actuating sprocket  36  from the channel  40 . This decoupling means, illustrated in FIG. 4, includes a toggle clamp  92 , actuated by a safety cord  94 . The toggle clamp is comprised of a plunger  96  juxtaposed so that when the plunger extends medially (i.e., toward the motor drive assembly), the plunger contacts a shaft  88  rotatably receiving and supporting the pinch roller  50 . 
     Upon actuation of the safety cord  94 , the plunger  96  is extended outwardly and against a surface of the pinch roll shaft  88  proximal to the clevis mount  98 . This action causes the lag plate  58  to become displaced outwardly, and towards the motor  34 , thereby causing similar displacement of the motor assembly platform  56  in a direction toward a longitudinal edge of the door and away from the center line of the motor assembly, with the center line defined by the channel  40 . As a result of these actions, the sprocket  36  disengages from the channel  40 . To more fully disengage the sprocket from the channel, the motor platform  56  can be spring biased toward the longitudinal edge of the door leaf, (i.e., and therefore in a direction perpendicular from the longitudinal axis of the channel  40 . As depicted in FIG. 3, this spring biasing can be effected by a spring  75 , having a first end attached to the first or proximal side  76  of the motor mount hinge  74  and a second end attached to the motor mount platform surface  84 . The spring is attached to a laterally facing surface  77  of the proximal side of the hinge. When the sprocket  36  is fully engaged with the channel  40 , the spring  75  is in an extended mode. However, when the toggle clamp  92  is actuated, the plunger from the clamp serves to move the motor mount platform  56  laterally (i.e., in a direction perpendicular to and away from the point on the longitudinal axis of channel  40  at which the sprocket is engaged). This plunger action facilitates the retractable characteristic of the spring and therefore facilitates axial movement of the motor platform relative to the hinge  74  a sufficient distance to decouple the sprocket  36  from the channel  40 . Aside from a retractable spring mechanism, a compressive spring can be utilized to facilitate sprocket decoupling. In such an arrangement, a medially facing surface  79  of the upwardly extending portion  78  of the motor platform  56  is contacted with a first end of the compressive spring while the second end of the compressed spring is attached to the platform support surface at a region intermediate the upwardly extending portion and the motor  34 . In this alternate spring biased configuration, the sprocket is pushed away from the channel by the spring. 
     Door Latching Mechanism 
     A myriad of mechanisms for maintaining the door leaf engaged with its door frame are possible, and well known in the art. However, FIGS. 5-8 depict an exemplary double-latching configuration unique to the industry. This door latching mechanism operates separate from the main door leaf drive, discussed supra, and in essence serves as a supplemental means for actuating the door leaf perpendicularly to the wall to effect an intimate seal between the leaf and the door jamb. 
     FIG. 5 presents an overview of the door latching mechanism as well as the door-leaf drive mechanism. The door latching mechanism is effected by communication of latch shafts  100  with latch block assemblies  101 , the later of which are anchored to the wall of the enclosure. The latch shafts  100  are slidably attached to the door leaf  12  via latch shaft guide ways  99  which are in turn attached to the door leaf. 
     Each of the latch shafts  100  interact with the latch block assemblies  101  via one or more protuberances  103  which are attached to and laterally extending from the latch shaft  100 . The protuberances  103  are arranged to slidably engage and disengage with each of the latch blocks upon axial actuation of the latch shaft  100 . The instant configuration depicts the latch shafts  100  at the periphery of the door leaf defined by the longitudinal edges of the door leaf. However, it should be appreciated that the latch shafts  100  can be similarly arranged so as to extend parallel to, and generally situated at, the horizontal edges of the door leaf. Detailed description of the latch-block mechanism is depicted in FIG.  7 . 
     FIGS. 6 and 7 provide a more detailed depiction of the latch shaft actuating system. For clarification, certain components have been eliminated, including the drive train channel  40  which normally is disposed intermediate the pinch roller  50  and sprocket  36 , and the secondary support bracket  22  which normally rests upon its bracket slide  26  and depends therefrom. 
     Axial actuation of the latch shafts  100  occurs either manually or via a latch shaft motor  102 . The motor  102  is mounted onto a latch shaft motor mount  104  which is generally flat in configuration and juxtaposed to one of the latch shafts so that the mount&#39;s longitudinal axis is parallel to the longitudinal axis of the latch shaft. 
     A second surface  110  of the latch shaft motor opposes an exterior surface of the door leaf (the leaf has been eliminated from the drawing for clarity) and slidably communicates with the leaf while remaining co-planer therewith. The point of slidable attachment of the mount  104  to the door leaf is a bolt  111  or rod extending perpendicularly to the mount  104  and extending transversely through the mount at a region of the mount forming a slot  109 , whereby the slot has a radius. The radius is configured relative to the latch motor shaft aperture  112 . The bolt is anchored to the door leaf, but free to travel within the confines of the slot. 
     The motor  102  is positioned on a first surface  106  of the mount so as to facilitate rotation of a spur gear  108  which is itself mounted proximal to the opposing, second surface  110  of the latch shaft motor mount  104 . The spur gear  108  is arranged so that the plane formed by its periphery is generally parallel to the plane formed by door leaf. 
     The motor  102  on the first surface  106  communicates with the spur gear  108  via a shaft slidably received through a region of the mount and door leaf which forms a transverse aperture  112 . In this configuration, the door leaf  12  is intermediate the second surface  110  of the mount and the spur gear  108 . 
     Intermediate the periphery of the spur gear  108  and an opposing longitudinally extending region of the latch shaft  100  is a gearway  114  itself attached longitudinally to the latch shaft so as to mesh with the periphery of the spur gear  108 . Upon actuation by the latch shaft motor  102 , the spur gear  108  turns circumferentially to effect a longitudinally extending motion to the latch shaft  100 . Reversing the polarity of the motor reverses the direction of extension of the latch shaft so as to selectively slidably engage or disengage the latch shaft  100  with a region of the door jamb (not shown) forming an aperture. 
     The action of the latch shaft which is proximal to the latch shaft motor assembly is coordinated with a latch shaft distal to the motor assembly via a cross latch drive shaft  116  situated intermediate the proximal and distal latch shafts and generally perpendicular to the two latch shafts  100 . Each end of the cross latch drive shaft  116  terminates with spur gears  118 . The peripheries of these spur gears  118  are mated with cross latch drive shaft gear ways  120  positioned on the shafts at approximately a 90 degree angle relative to the gearway  114  juxtaposed to the latch shaft motor  102 . As such, upon actuation of the proximal latch shaft, the cross latch drive shaft serves to actuate the distal drive shaft in an identical manner. 
     FIG. 8 is a view of FIG. 5 taken along line  8 — 8  and depicts detail of the communication between the latch shaft protuberance  103  adapted to be slidably received by the latch block  101 . The view in FIG. 8 depicts the latch shaft  100  engaged with the latch block  101 . To engage the latch shaft with the block, the latch shaft is actuated axially and in this case upwardly so as to cause the protuberance  103  to contact a cam surface  105  of the latch block  101  in such a manner so as to be confined by the surface. The cam surface  105  extends generally inwardly along the longitudinal axis of the latch block but also deviates laterally from the longitudinal axis so as to cause the protuberance to travel along the cam surface and toward the wall  14  of the enclosure  16  defining the door jamb. This action causes the entire door to move perpendicularly to, and toward the door jamb to effect a more complete seal with the door jamb. It is this additional perpendicular action of the door leaf toward the plane of the door jamb that necessitates the linear carriage  62  and linear way  64  configuration on the first motor mount platform  56 , in as much as such perpendicular action (relative to the plane defined by the door jamb) can vary as much as a few inches once the door leaf is positioned by the door leaf actuating motor  34 . In essence, and as noted supra, this supplemental, additional perpendicular movement is effected via a second motorized mechanism that is separate from the main door leaf drive mechanism. 
     To assure precise mating of the protuberance  103  with the cam surface  105 , the latch shaft guideways  99  which are juxtaposed medially to the cam surface define a longitudinally extending channel  97  adapted to slidably communicate with the protuberance. As such, the channel  97  accommodates slidable movement of the protuberance relative to the longitudinal axis of the guideway  99  whenever the latch shaft is actuated as described supra. 
     A safety cord  122  provides for manual decoupling of the motor mount latch shaft gearway  114  from the motor mount spur gear  108 . In an engaged configuration, the spur gear mates fully with the gearway  114 , via pressure applied laterally onto a peripheral region of the mount  104  by a plunger  115  of a second toggle switch  113 . However, when the toggle switch  113  is actuated by the safety cord  122 , the plunger  115  of the second toggle lever  113 , retracts medially, i.e., in a direction away from the mount  104 , thereby resulting in a relaxation of the mating interaction between the spur gear  108  and gearway  114 . To more fully retract the spur gear from the gearway, the mount can be spring-based medially at a region of a medial edge  119  of the motor mount plate  104  juxtaposed to a medial end of the slot  109 . The spring biasing is effected via a spring  117  attached at one end to the region of the medial edge  119  of the motor mount plate  104 , and attached at another end to a stationary point  121  (also depicted on FIG. 6) on the door leaf and in a direction toward the midline of the door leaf. 
     When the plunger is retracted manually via the safety cord  122 , the depending end of the spring biased motor mount plate  104  swings medially, causing a disengagement of the spur gear  108  from the gearway  114 . Once disengaged, the door can be unlatched manually. 
     Latching and unlatching of the door leaf may be effected remotely, again a special advantage in high-radiation, toxic, or otherwise hazardous environments. 
     Exemplary Embodiment 
     The method for a dual movement door leaf disclosed herewith is applicable in a myriad different situations. The advantages it provides are most useful where a very thick door is required. This is a case with bank vaults, magnetically shielded enclosures, and especially for anechoic chambers where cones must protrude from the inside face of the door leaf. A hinge-pivoted door is most undesirable in such cases. 
     A prototype door for an anechoic chamber incorporating the features of this invention has been constructed by the inventors. 
     A wide variety of materials can be employed in the fabrication of the present invention. For examples, the motors, sprocket wheels, drive chain, rails, glides, and other elements of the device are commercially available and for each of these there are several alternate designs available. The door leaf, carriage, rails, manifold, and other individual components can be manufactured from commonly available ferrous or non-ferrous elements and compounds, including but not limited to steel, aluminum, brass, copper, mu-metal, plastic, glass, composites, and other substrates. 
     In brief, the present invention provides a device for positioning and moving a door leaf perpendicular to and also parallel to the wall defining a jamb of the door. The door is slidably suspended on a first set of rails supported by a carriage. The carriage itself slides on a second set of rails parallel to the wall so that a single channel, a single motor, and a single drive acting on a single drive chain are utilized to cause the leaf first to move perpendicular to the door opening and then parallel thereto as the door is opened and conversely when the door is closed. This action can be reversed so that a door is slid parallel to a plan defined by a doorjamb after first being positioned co-planarly from a point perpendicular to the plane. 
     The device is designed to be actuated solely by electric power, and does not require pneumatics. Actuation can be effected remotely from a central control panel while feedback information is supplied by a series of roller switches located at different positions along the tracks mating with the main actuating motor  34 . This remote actuation confers special advantage in high-radiation, toxic, or otherwise hazardous environments. 
     While the invention has been described with reference to details of the illustrated embodiment, these details are not intended to limit the scope of the invention as defined in the appended claims.