Abstract:
A pull-out mechanism for mounting a drawer in a drawer cavity of a piece of furniture. The mechanism may include an upper pull-out rail with a substantially U-shaped cross-section affixed to the drawer and may optionally include a lower rail with a substantially U-shaped cross-section affixed to a wall in a drawer cavity. The mechanism may also have an intermediate rail, which is disposed between the upper rail and the lower rail, or alternatively may support the upper rail while attaching to the wall. One or more bearing holders provided with at least one ball bearing and a plurality of rollers or wheels supports the upper rail and optional lower rail in a mounted relationship with the intermediate rail.

Description:
TECHNICAL FIELD 
     The invention relates to a pull-out mechanism for mounting of a preferably large and heavy pull-out drawer in a drawer cavity in a piece of furniture, especially a filing cabinet, and which includes an upper rail with a substantially U-shaped cross-section, said upper pull-out rail being affixed to the drawer in the longitudinal direction of the drawer, and possibly a lower rail with a substantially U-shaped cross-section, said lower rail, possibly indirectly, being affixed to a wall in the drawer cavity, and an intermediate rail which in its longitudinal direction is movable between the upper rail and the lower rail, and where at least one bearing holder with rollers and balls is inserted between the intermediate rail and the upper rail and the lower rail respectively. 
     BACKGROUND 
     A mechanism is known for a drawer, where an intermediate rail is placed between an upper rail connected to a telescopic drawer and a lower rail, which is connected to the closet which the drawer is part of; said intermediate rail follows the drawer gradually when the drawer is pulled out of the closet. Pairs of rollers and bearing balls are placed between the rails; the bearing balls, however, make the pull-out mechanism rather complicated and thus vulnerable. 
     DISCLOSURE OF THE INVENTION 
     The aspect of the invention is to provide a pull-out mechanism of the above kind, and which facilitates a simpler, and thus more reliable, structure than known. 
     The pull-out mechanism according to the invention is characterised in that exactly one bearing ball is mounted in the part of the individual bearing holder placed on one side of the intermediate rail, whereas two rollers or wheels, the axes of which are placed in their individual planes of two planes standing perpendicular to each other, are mounted in the part of the above bearing holder, which is placed on the other side of the intermediate rail, where a substantially horizontal auxiliary roller extending to both sides of the intermediate rail is mounted in the bearing holder between the intermediate rail and the upper rail and the lower rail respectively. Hereby a considerably constructive simplification is achieved and the pull-out mechanism can bear both horizontal and vertical loads in a reliable way. Furthermore it is possible to pull out the drawer to a position just outside the actual piece of furniture. 
     Moreover, according to the invention, the invention may be modified such that the lower rail complete with bearing holder and roller and ball is removed, and that the lowermost part of the intermediate rail is affixed to the wall of the drawer cavity, possibly after bending of said lowermost part. Thereby it is achieved that the pull-out mechanism becomes simpler as it only has two rails now: the intermediate rail and the upper rail. 
     In a particular embodiment according to the invention, a more elevated auxiliary rail with a substantially U-shaped cross-section may be placed between the upper rail and the drawer, where the outer ends of the U are bent approx. 90° inwards, and where at least one auxiliary roller in at least one auxiliary holder is placed between the upper rail and the more elevated auxiliary rail. Thereby it is achieved that the pull-out mechanism works particularly reliably even when the drawer is pulled entirely out of the piece of furniture. 
     According to the invention, incliningly extending web parts, which can serve for the fixation of the bearing holders in relation to the intermediate rail, may be provided locally on the intermediate rail. Hereby particularly good options are achieved for a reliable affixation of the bearing holders to the intermediate rail and thus a particularly reliable running of the drawer when it is pulled out or pushed in (closed). 
     According to a further embodiment of the invention, the intermediate rail may have a cross-section corresponding to an I, where the intermediate rail may preferably be manufactured by bending of a metal sheet, especially such that each of the webs of the intermediate rail includes two layers of metal sheets. Thereby it is achieved that the pull-out mechanism can be manufactured in a particularly simple way. 
     In a particular embodiment according to the invention, the individual bearing ball may be mounted in a cavity or a slot in the bearing holder, a part of the wall of the cavity or the slot preferably having the same curvature as the surface of the bearing ball. Thereby a particularly reliable retaining of the individual bearing ball in its bearing holder is achieved. 
     According to the invention, the individual bearing ball may have a diameter of more than 2 mm, preferably more than 3.5 mm. Thereby it is achieved that the pull-out mechanism can bear considerable weight from the drawer. 
     According to a particular embodiment according to the invention, one or more cramping means for affixing the piece of furniture to the floor or wall in the room, in which the piece of furniture is to be placed, are joined in connection to the pull-out mechanism—possibly, however, to the outer side of the piece of furniture. Hereby it is ensured that the piece of furniture does not tilt towards (or onto) a user who has pulled or is pulling one or more drawers out of the piece of furniture. 
     Finally, according to the invention, at least one auxiliary wheel, which is placed between the elevated auxiliary rail and the upper rail, is mounted to the upper rail. Hereby it is achieved that the load from the weights in the drawer is transferred particularly reliably to the piece of furniture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in detail below with reference to the drawings, in which 
         FIG. 1  shows a cross-section in a first embodiment of a pull-out mechanism according to the invention including an upper rail, a lower rail as well as an intermediate rail placed between the upper fail and the lower rail, 
         FIG. 2  shows another embodiment of the pull-out mechanism according to the invention including an upper rail and an intermediate rail, and where a part of the latter is bent sideward for affixing to a wall in the drawer cavity of the piece of furniture, 
         FIG. 3  shows a third embodiment of the pull-out mechanism according to the invention, where an elevated auxiliary rail is placed between the upper rail and a drawer, said elevated auxiliary rail being affixed to the drawer whereas a part of the intermediate rail is bent sideward for affixing to a wall in the drawer cavity, and 
         FIG. 4  is a perspective view of a pull-out mechanism according  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The pull-out mechanism  1  shown in  FIGS. 1 and 4  is intended for mounting of a preferably big and heavy drawer  2  in a drawer cavity  3  inside a piece of furniture  4 . The latter may e.g. be a filing cabinet. The pull-out mechanism  1  includes an upper pull-out rail  6 , which is fastened to the drawer  2  in the longitudinal direction of the drawer (i.e. perpendicular to the plane of the paper in  FIG. 1 ), and a lower rail  8 , which is fastened to a wall  5  in the drawer cavity  3  of the piece of furniture  4  by means of fittings  9 . An intermediate rail  10  is placed between the upper rail  6  and the lower rail  8 , said intermediate rail being movable in its longitudinal direction, cf.  FIG. 4 , while it is placed between rails  6  and  8 . Between the intermediate rail  10  and the upper rail  6 —and at the same time to the left of the intermediate rail, especially its vertical centre plan X-X—a bearing holder  12  is inserted; possibly one or more additional bearing holders may be provided which are placed further back behind the plane of the paper. Each bearing holder is provided with two rollers  14  and  15 , the one roller  14  having a horizontal axis of rotation not shown and the other roller  15  having a vertical axis of rotation not shown. A bearing ball  16  is mounted to a part  12   a  of the individual bearing holder  12 , said part being placed at the right side of the intermediate rail  10 . As can be seen, the roller  14  can bear vertical loads in the pull-out mechanism while the roller  15  can bear horizontal loads; the ball  16  can bear both vertical and horizontal loads. As shown, a wide, substantially horizontal auxiliary roller  18  is mounted between the upper rail  6  and the intermediate rail  10 ; said auxiliary roller  18  extends into both sides of the intermediate roller  10 , i.e. both sides of the vertical centre plane X-X of the intermediate roller  10 . 
     As shown in  FIG. 1 , at least two bearing holders  22  may be inserted between the intermediate rail  10  and the lower rail  8 , where two rollers  24  and  25  (corresponding to the afore-mentioned roller  14  and afore-mentioned roller  15 ) are mounted between the intermediate rail  10  and the lower rail  8 . These rollers are at the same side of the aforementioned centre plane X-X as the rollers  14  and  15 . Precisely one bearing ball is placed at the opposite side of the centre plane X-X—i.e. at the same side as the ball  16 . An auxiliary roller  28  is mounted between the intermediate rail  10  and the lower rail  8 , said auxiliary roller extending on both sides of the vertical centre plane X-X of the intermediate rail  10 , i.e. in substantially the same way as the auxiliary roller  18 . 
     When the pull-out mechanism shown in  FIGS. 1 and 4  is used in connection with pulling out or pushing in a drawer, the pull-out mechanism can bear both vertical loads in a reliable way (e.g. the weight of items placed in the drawer) and horizontal loads (e.g. loads arising from the drawer not being pulled out of the drawer cavity evenly, but “wobbling” slightly). The loads to be absorbed sideways, however, are considerably smaller than the loads to be transferred vertically by the pull-out mechanism. 
       FIG. 2  shows another embodiment of the pull-out mechanism according to the invention. It includes an upper pull-out rail  6 ′ and an intermediate rail  10 ′, but the lower rail (compare rail  8  in  FIG. 1 ) does not exist. The intermediate rail  10 ′ is bent sideward and fastened to a wall  5 ′ of a piece of furniture  4 ′ defining the drawer cavity  3 ′. The drawer  2 ′, which is to be able to be pulled out and pushed in, is affixed to the side of the upper rail  6 ′ as shown, but it may also be affixed on top of the latter. 
     As shown, precisely one bearing ball  16 ′ is mounted to a part  12   a ′ between the upper rail  6 ′ and the intermediate rail  10 ′ —at the one side of a vertical “centre plane” X′-X′ (partly corresponding to the plane X-X in  FIG. 1 ) —and two rollers or wheels  14 ′,  15 ′ (the axes of which lie in two planes being perpendicularly on each other, said planes being perpendicular on the plane of the paper) are mounted at the other side of the afore-mentioned vertical centre plane. A transverse auxiliary roller  18 ′, which extends at both sides of the afore-mentioned vertical centre plane X′-X′, is placed above the rollers/wheels  14 ′,  15 ′. 
     As shown in  FIG. 3 , a substantially U-shaped auxiliary rail  7 ″ may be mounted on the outside of and above the upper rail  6 ″. In this case the drawer (not shown) is mounted on the auxiliary rail  7 ″. Inside the upper rail  6 ″, a rail  10 ″ is bent sideward and fastened to a wall  4 ″ defining a drawer cavity  3 ″, is mounted by means of just one bearing ball  16 ″; the bearing ball  16 ″ is mounted at part  12   a ″ and placed at one side of the rail  10 ″, while on the other side of said rail  10 ″ two rollers or wheels  14 ″,  15 ″, corresponding to the rollers or wheels  14 ′,  15 ′ in  FIG. 2 , are placed. Furthermore, a transverse roller  18 ″ corresponding to roller  18 ′ in  FIG. 2  is provided. As shown, at least one auxiliary roller, here more specifically three auxiliary rollers  19   a ″,  19   b ″ and  19   c ″, may be inserted between the elevated auxiliary rail  7 ″ and the outer side of the upper rail  6 ″. This roller or these rollers are mounted onto —or rather into the recess in —an elevated bearing holder  23 ″. The auxiliary rollers  9   a ″ and  19   c ″ can rotate around their individual axes (not shown) when the auxiliary rail  7 ″ is pulled out. Similarly the auxiliary wheels  24   a ″ and  24   b ″ can rotate around their individual horizontal axes, cf. e.g. axis  31 , which is indicated with dots and which is affixed onto the rail  6 ″. 
     While the outer ends of rail  6 ″ are bent mainly 90° inwards, the same may also apply to the auxiliary rail  7 ″, cf. the inwardly bent parts  25   a ″ and  25   b″.    
     As shown in  FIGS. 1 ,  2  and  3 , incliningly extending web parts  26 ,  27 ,  26 ′,  26 ″, which can serve for the affixation of the mentioned bearing holders  12 ,  22 , and  12 ′,  12 ″ respectively, may be provided on the intermediate rail  10 ,  10 ′ and  10 ″ in relation to the intermediate rail  10  and  10 ′,  10 ″. 
     As shown in  FIG. 1 , the intermediate rail  10  may have a cross-section substantially corresponding to an I, and said rail may preferably be manufactured by bending of a metal sheet, each of the webs of the intermediate rail including two layers of metal sheet. 
     The individual bearing ball  16 ,  29 ,  16 ′,  16 ″ may be mounted in a cavity or a slot in the bearing holder  12 ,  22 ,  12 ′,  12 ″, which, however, is not shown; in this case a part of the wall of the cavity or the slot has substantially the same bending as the surface of the bearing ball, thus efficiently keeping the latter in its place. 
     The individual bearing ball  16 ,  29 ,  16 ′,  16 ″ may have a diameter of more than 2 mm, preferably more than 3.5 mm. 
       FIG. 4  is a perspective view—cf. FIG.  1 —of how the lower rail  8 , the intermediate rail  10  and the upper rail  6  may extend in relation to each other. Preferably the rails are equally long, the lengths may, however, also be differing as shown in  FIG. 1 , as the upper rail  6  and the intermediate rail  10  may be relatively long (have the length l ø ), while the lower rail  8  may be somewhat shorter (have the length l n ); thus l ø  is considerably bigger than l n . 
     The invention may be varied in many ways without deviating from the idea behind the invention. Thus rails, bearing holders, balls and rollers may be manufactured from various different materials. Preferably the rails are steel rails, while the bearing holders may be of hard plastics, and rollers and balls may be of the kind used in ball bearings and roller bearings. Regarding  FIGS. 2 and 3 , the rail  10 ′ and  10 ″ respectively may be affixed indirectly onto the wall  3 ′ and  3 ″ respectively.