Pull-out guide for drawers
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a pull-out guide for drawers or the like and includes one supporting rail and one pull-out rail on each side of the drawer and at least two rollers or the like transmitting vertical forces arising between the pull-out rail and the supporting rail and being mounted in a roller carrier in the form of a carriage. The carriage is provided with locking means which lock the carriage in the push-in direction of the pull-out guide, when the pull-out rail is pulled free of the supporting rail. 
     2. Description of the Prior Art 
     Such pull-out guides are widely used with drawers, shelves and the like in modern furniture production, particularly in kitchen furniture production. 
     In general the purpose of such guides is to facilitate the moving of the drawer and to avoid any obstructions during this movement. 
     In addition to known drawer guides, which comprise rollers or slides, the rollers and slides being fixed directly to the supporting and pull-out rails, an increasing number of pull-out guides for drawers have been used lately in which, as mentioned above, the rollers are carried by a cage or the like and float between the supporting and pull-out rails. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a pull-out guide of the above-mentioned kind in which the carriage is locked, when the drawer is pulled out, so that the carriage cannot unintentionally move forward or backward in the rail and that the carriage is prevented from tilting sideways, out of the rail it runs in, when a U-shaped profile rail is used. 
     By means of the present invention high operational reliability may be obtained and it is possible to omit movable parts in the prior art securing mechanism. 
     It is very important to prevent the carriage from tilting laterally. In general, the rail in which the carriage is guided, which rail can either be the pull-out rail or the supporting rail, has a C-shaped profile, whereby the outer edges of the rail embrace the carriage, thus holding the carriage securely in the rail. It is a disadvantage of this arrangement, that the production of C-shaped profile rails requires complicated machines. Such a profile cannot be produced by means of a simple press, at least not in one operating cycle, because of the inward bent edges of the C-shaped profile rail. 
     According to the invention securing of the carriage is achieved by providing a cam or the like preferably disposed centrally on the carriage, such cam resting against the supporting flange of the rail taking up said carriage and said carriage being tiltable around said cam, whereby two parallel flanges are provided on the upper edge of the carriage, such flanges taking up between each other a projection of the rail, when the carriage is tilted around the cam, the projection being formed, for example, by an angled part of the upper horizontal flange of the rail. 
     It is preferably provided that one cam is provided on the lower side and one cam on the upper side of the carriage, the cams lying opposite each other, the upper cam corresponding with a lateral stop of the rail, thereby obtaining a good guiding of the carriage. 
     When the drawer is pulled free of the cabinet, the carriage is secured against tilting, also if the rail has a U-shaped profile and not a C-shaped profile. It can preferably be provided that at least one flange is spring mounted, so that it is laterally pressed against the angled part of the upper horizontal flange. A clamping effect is obtained thereby, which improves the holding of the carriage. 
     Preferably, a projection is formed on the carriage diametrically opposite the flanges. near to its front and rear end, a tilting of the carriage around a vertical axis is prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following an embodiment of the invention will be described in more detail with reference to the drawings, without being limited thereto, wherein: 
     FIG. 1 is a schematic side view of a pull-out guide in accordance with the present invention, wherein the drawer is shown pushed in, wherein only the carriage and the rail taking up the carriage are shown, and wherein the rail guided within the carriage by means of a flange is shown with dotted lines for the purpose of better illustration; 
     FIG. 2 is a view similar to FIG. 1, but with the drawer shown pulled out; 
     FIG. 3 is a sectional view along line I--I of FIG. 1; 
     FIG. 4 is a sectional view along line II--II of FIG. 2; and 
     FIG. 5 is a perspective view of section A of FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The pull-out guide in accordance with the present invention substantially comprises a supporting rail 1 on the side of a body, e.g., a furniture body, a pull-out rail 2 on the side of a drawer to fit into the body, and a carriage 3, pull-out rail 2 providing a horizontal channel within the drawer as illustrated, or alternatively within the body, for housing carriage 3. Load-transmitting rollers 4 are mounted in the carriage 3. 
     It is an essential feature of the present invention that the rail in which the carriage 3 is guided may be either the pull-out rail or the supporting rail. It is essential that one rail takes up the carriage, while the second rail, i.e., the supporting rail 1 on the side of the body according to the present illustrated embodiment, projects with a horizontal flange 1&#39; between the rollers 4 of the carriage 3. 
     In illustrated embodiment the rollers 4 are mounted with clearance and without axles in the carriage 3, i.e. corresponding recesses and projections are laterally disposed in the carriage 3 and on the rollers 4, whereby the rollers 4 are kept in the carriage 3, but can be moved to a certain extent, the roller 4 lying opposite a stop surface 9 at least to the height of a stop 8. 
     Also disposed in the carriage 3 are lateral compensating rollers 5 which are mounted in the same way as the rollers 4 and improve the lateral guiding of the drawer. 
     As can be seen in FIG. 3, the pull-out rail 2 on the side of the drawer has a U-shaped profile, and the supporting rail 1 on the side of the body has an L-shaped profile. The body and the drawer are indicated in this figure by dots and dashes. As already mentioned, the carriage 3 of this embodiment is guided in the pull-out rail 2 on the side of the drawer. 
     The carriage 3 has a projection 6 near its front end serving as a lock and extending into a recess 10 in the lower horizontal flange 2&#34; of the pull-out rail 2, when the drawer is pulled out of the pull-out guide. 
     In the illustrated embodiment cams 7 are disposed approximately in the center of the carriage 3 on its upper side 3&#34; as well as on its lower side 3&#39;, the carriage 3 being tiltable around cams 7. The cams 7 are adapted to slide or almost slide on the two parallel flanges 2&#39;, 2&#34; of the pull-out rail. 
     When the drawer is pushed into the body, i.e. when the horizontal flange 1&#39; of the supporting rail 1 is positioned between the rollers 4, the projection 6 is, as shown in FIG. 1, positioned within the U-shaped profile of the pull-out rail 2, and the carriage 3 is freely movable on the supporting rail 1 and in the pull-out rail 2. 
     At the front end of the supporting rail 1, a stop 8 is preferably disposed on the horizontal flange 1&#39;, as indicated in FIG. 2. Stop 8 can, for example, be bent out of the horizontal flange 1&#39; of the supporting rail 1. 
     When the drawer is pulled in the direction toward the right side of FIGS. 1 and 2, the horizontal flange 1&#39; of the supporting rail 1 is successively pressed against stop surfaces 9, 9&#39; of the carriage 3. Thereby the carriage 3 is tilted around the lower cam 7 in the direction of arrow Z, and the projection 6 is pressed into the recess 10 of the pull-out rail 2. This process obviously only takes place when the carriage 3 is positioned at the rearmost end of the pull-out rail 2, i.e. in the position shown in FIGS. 1 and 2. The further pulling out of the carriage 3 during the pulling of the drawer is prevented by means of stops 11. 
     When the carriage 3 is tilted around the cam 7, not only the projection 6 engages with the recess 10, but two parallel flanges 12 of the carriage 3 are also lifted and take up between each other an angled part or projection 13 of the upper horizontal flange 2&#39; of the pull-out rail, as can be seen particularly in FIG. 5. As the carriage 3 is made of plastic, one of the two parallel flanges 12 is spring portion 12a which is resiliently biased or mounted and bent towards the other parallel flange 12, as shown in FIG. 5, the carriage 3 is clamped to the angled part 13. 
     The upper horizontal flange 2&#39; of the pull-out rail 2 is preferably provided with a further angled part 14 laterally contacting the upper cam 7 of the carriage 3, so that the carriage is absolutely secured against lateral tilting. 
     The releasing of the carriage 3 is automatically effected by moving the horizontal flange 1&#39; into the carriage 3 when the drawer is moved into the horizontal level thereof. 
     As can particularly be seen in FIGS. 1 and 2, the carriage 3 has a step-shaped separating slot 15, which separates a portion 16 of the carriage 3 carrying one roller 4 from the rest of the carriage 3. As the carriage 3 is made of plastic, portion 16 and the roller 4 are thus resiliently biased or spring mounted with respect to the remainder of carriage 3, i.e. when pushing the drawer onto the supporting rail 1, the roller 4 can evade the stop, thereby preventing the carriage 3 from being pushed down by the angled part 13 on which it is supported by means of flanges 12, and enables the carriage to freely move onto the rail.