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This application is a continuation of application Ser. No. 07/308,619 filed Feb. 10, 1989, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a device for supporting folding doors and, in particular, to a device for supporting suspension type folding doors capable of being moved right and left while kept folded. 
     BACKGROUND OF THE PRIOR ART 
     A drawback common to folding doors is that when the suspension bases which are the running members for suspending the folding doors approach each other for folding of the doors the doors are brought into a state similar to suspension from a point and are likely to sway sideward, thereby becoming hard to move. 
     For preventing such a sideward sway of the folding doors at the time of folding, prior art solutions, e.g., as disclosed in Japanese Utility Model Registration Official Gazette, No. 62-7832, have been proposed. In the device according to this prior art, running members are respectively provided with projections each directed toward and adapted to abut on the other. Guide rolls are provided on both sides of each projection in such a manner that respective tips of both projections abut on each other for keeping the doors folded roughly into the shape of a &#34;V&#34; while preventing the doors from folding so much as to be parallel with each other, to thus prevent sideward sway of the folding doors. 
     Such a device, however, has the considerable drawback that the doors are folded in the shape of a &#34;V&#34; opening at a large angle and not in parallel with each other and thus may be obstructive when near a space to be used as a passageway. Particularly, when a combination of a plurality of folding doors capable of moving right and left along rails are used for a partition, a width of opening of the opened partition is largely reduced as far as the doors are folded in the &#34;V&#34; shape and, therefore, the partition is not suitable for substantial service unless the folding doors are removed. 
     SUMMARY OF THE DISCLOSURE 
     A primary object of the present invention is to provide a folding door supporting device of a simple structure which permits the doors to be folded almost parallel to and as close as possible to each other at their respective wide sides and, in addition, is provided with upper liners capable of effectively preventing sideward sway of the folding doors. 
     This object is realized by providing an apparatus for securely and movably supporting a pair of folding doors hinged to each other at their respective adjacent vertical sides, comprising an upper rail member, comprising flanges respectively defining elongate horizontal first and second parallel upper door guide rails, a lower rail member comprising flanges respectively defining elongate horizontal first and second parallel lower door guide rails disposed respectively below and parallel to said first and second upper door guide rails, a first door support means for pivotably supporting a first one of said pair of folding doors solely on said first upper door guide rail, attached to said first door at a predetermined distance from the hinged side thereof and engaging with said first and second upper guide rails and said first and second lower guide rails to be movably guided therealong; and a second door support means for pivotably supporting a second one of said pair of folding doors solely on said upper door guide rail, attached to said second door at a predetermined location from the hinged side thereof and engaging with said first and second upper guide rails and said first and second lower guide rails to be supported by and movably guided therealong. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a part of an upper running liner according to the present invention; 
     FIG. 2 is a partially sectioned plan view of the closed folding doors, at II--II per FIG. 4. 
     FIG. 3 is a partially sectioned plan view of the folded doors, at III--III per FIG. 4. 
     FIG. 4 is a vertical sectional view of one of the doors; 
     FIG. 5 is a sectional view of vertical distance adjusting means for the upper running liners according to a preferred embodiment; 
     FIG. 6 is a sectional view of another kind of vertical distance adjusting means; 
     FIG. 7 is a perspective view of a part of the lower running member; 
     FIG. 8 is a sectional view of a roller part of the lower running member; and 
     FIG. 9 is a sectional view taken along the line B--B in FIG. 8. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the present invention will now be described in detail with reference to the drawings. 
     In FIG. 2, the reference character &#34;A&#34; indicates a folding door composed of a pair of doors 1a and 1b foldably connected to each other through hinges 25. The doors 1a and 1b are provided with upper running liner supporting members 3a and 3b, to which running liners 4a and 4b are fixed at uppermost ends thereof through draw type sliding hinges 2a and 2b, respectively. Stays 5a and 5b extend from the respective running liners supporting members 3a and 3b generally toward each other. These stays 5a and 5b are arranged on separate parallel lines to avoid collision therebetween when they approach each other. Additional running liners 6a and 6b, also running on separate rails, are respectively provided on the tips of the stays 5a and 5b, respectively. In the embodiment shown in the drawings, the running liners 4a and 6a are adapted to run on the rail 7a of the cross-sectionally channel-like rail member 7, with the other running liners 4b and 6b running on the parallel adjacent rail 7b on the other side. 
     The running liner supporting members 3a and 3b are each provided with stabilizer rollers 8, each rotating around a vertical axis as best seen in FIGS. 1 and 4. These stabilizer rollers 8 are disposed in the opening 7c of the channel-like member 7, between the rails 7a and 7b thereof, and prevent the folding doors from swinging back-and-forth during use of the folding doors. 
     Running liner supporting members 3a and 3b are fixed to sliding hinges 2a and 2b so as to be positionally adjustable with respect to the hinges through vertical distance adjusting means 9 and horizontal distance adjusting means 10. See FIGS. 1 and 4. 
     Vertical distance adjusting means 9, as shown in FIGS. 1 and 5, include an axial member 11 depending from the running liner supporting member 3a or 3b and a fixing member 13 which is connected to one of sliding hinges 2a or 2b, and are provided with a fixing member 13 having a cylindrical part 12 to receive the axial member 11. The axial member 11 is fitted into the cylindrical part 12 to be movable with respect thereto only in the vertical direction while being prevented from rotating by a diametrally different upper part 11a of the axial member 11, and a threaded part 11b is driven into a nut member 14 only rotatably fixed to the middle part the cylindrical part 12. The running liner 4a or 4b, therefore, can be readily adjusted vertically by turning of the nut member 14. 
     Vertical adjustment from the lower side, similarly, may easily be performed by an arrangement that has, as shown in FIG. 6, a nut member 14&#39; fitted into the fixing member 13, from the lower side of the cylindrical part 12 and retained rotatably and undetachably by a coupling 15. 
     Horizontal distance adjusting means 10 is formed in such manner that a base plate 26 is secured to one of hinge members 2a and 2b made to be adjustable in the horizontal direction, and is fixed to the fixing member 13 to be horizontally adjustable by means of an oblong hole 27 and a setting screw 28. See FIG. 1. 
     A structure is provided per FIG. 5, in which the cylindrical part 12 of the fixing member 13 is divided at the midpoint, and has upper and lower parts 12a and 12b disposed symmetrically with respect to the middle point. A nut member 14 provided to mesh with the shaft member 10 is fitted into the space between the upper and lower cylindrical parts 12a and 12b. This structure is usable as a fixing member applicable to either side of the door, because the function thereof is not changed when the structure is inverted and transferred from one side to the other, thereby enabling reduction in the number of different component parts required. 
     To the lower parts of the doors 1a and 1b, lower running liners 19 are fixed through sliding hinges 16, fixing members 17, and lower running liner supporting member 18. The running liner supporting member 18 is preferably provided with a vertical shaft 18a of non-circular cross-section which is inserted into a cylindrical part 17a of the fixing member 17 so as to be vertically displaceable and is further provided at its top end with a cushion spring 24 constantly acting downward to provide an upwardly directed reaction force acting to supporting fixing member 17. This mechanism mitigates vertical vibration at the time of running of the door. See FIG. 7. 
     The running liner 19 is shaped, as shown in FIGS. 8 and 9, to run along a channel-like lower rail member 20 having an upper narrow opening between parallel rails 20a and 20b, and is composed of two upper rollers 21, 21 to run on the uppermost surfaces of the rails 20a and 20b of the rail member 20 and of a pair of lower rollers 22 disposed to run along the parallel bottom surfaces of the rails 20a and 20b while racing the upper rollers 21, 21 with horizontal thicknesses of the rails 20a and 20b between, the upper rollers 21 each being provided with an insert 23 to be fitted into the opening between the rails 20a and 20b for closing a part of the opening. Such a structure, as described above, prevents the doors 1a and 1b from floating and swaying sideward. 
     In the above-described structure, due to the arrangement in which stays 5a and 5b as well as the additional running liners 6a and 6b (at the tips of the stays) are disposed on parallel lines, the doors 1a and 1b are freed from collision therebetween when folded at the hinges. The doors, therefore, can be folded to be almost parallel with and close to each other at their sides, whereby an open distance between the doors can be made large. The doors 1a and 1b are suspended while folded, by two liners appropriately spaced from each other by the stays, i.e., the upper running liners 2a and 2b as well as sub-liners 4a and 4b. Hence they are retained in stable manner without sideward sway, to be capable of smooth opening and closing and also of smooth displacement while in a folded state, thereby serving as an effective partition. Furthermore, because the running liner supporting members are fixed to the door to be positionally adjustable by the vertical distance adjusting means 10 with respect to the hinge members and by the horizontal distance adjusting means 13, the desired balance between the folding doors in the horizontal direction and any gap against the rail can be easily adjusted to ensure exact suspension of the doors. 
     In this disclosure, there are shown and described only the preferred embodiments of the invention, but, as aforementioned, it is to be understood that the invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.

Summary:
Apparatus is provided for securely and movably supporting a pair of folding doors hinged to each other at adjacent vertical sides and guidedly supported between upper and lower parallel rail members each of which includes a pair of elongate parallel guide rails. Elements provided on each of the two hinged doors engage the respective upper guide rails and both of the lower guide rails to be supported thereby and to be guided therealong so that the two hinged doors can be easily folded to be almost parallel to each other to permit wide opening of a doorway opening.