Abstract:
A fastening device for furniture fittings on furniture parts which includes at least one dowel core that can be inserted into a hole of a furniture part. The dowel core can be arranged inside a dowel sleeve, and an actuating device moves the dowel sleeve relative to the dowel core. The dowel sleeve spreads on the dowel core and the dowel core is radially resilient.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of International No. PCT/AT2010/000328, filed Sep. 13, 2010, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The invention relates to a fastening device for furniture fittings on furniture parts having a dowel core arranged inside a dowel sleeve, a furniture fitting having such a fastening device, a furniture part having such a furniture fitting and an item of furniture having such a furniture part. 
     (2) Description of the Related Art 
     The advantage of fastening furniture fittings using dowel-like clamping parts rather than fastening using screws lies in the fact that assembly can be carried out without tools, and so assembly times can be shorter. A further advantage of dowel-like clamping parts lies in the fact that, unlike screws, they cannot be “over-tightened”; when using screws, this can lead to worsening of the hold of the furniture fitting in the furniture part. 
     Thus, DE 200 02 994 U1 discloses a fitting for detachable fastening to a furniture part having a fitting body adjacent to the furniture part having at least one sleeve-like anchoring part that can be inserted into a drilled hole of the furniture part, wherein a clamping portion for the sleeve-like anchoring part that preferably bears on the fitting body is provided on the side of the fitting body facing away from the furniture part. 
     WO 1999/024723 A1 discloses a fitting for detachable fastening to a furniture part, having a fitting body adjacent to the furniture part, at least one dowel-like expansion sleeve that can be inserted into a drilled hole of the furniture part, having a plurality of axially offset retaining projections on its sheath, preferably having a conical tip and a peg-like expansion part for the expansion sleeve which projects out of the fitting body, wherein a clamping portion for the expansion sleeve which advantageously bears on the fitting body is arranged on the side of the fitting facing away from the furniture part. 
     EP 1 054 168 A2 and DE 295 06 600 U1 disclose further examples of the prior art. 
     The furniture fittings mentioned above suffer, however, from the disadvantage that the material of the furniture part is not taken into consideration as regards the transmission of load from the fastening device to the furniture part. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention aims to avoid the disadvantage described above and to provide a fastening device for furniture fittings that is improved over the prior art, an improved furniture fitting, an improved furniture part and an improved item of furniture. 
     This aim is accomplished by a fastening device having the features described below, a furniture fitting having such a fastening device, a furniture part having such a fitting, and an item of furniture having such a furniture part. 
     The effect of such a resilient dowel core is such that when the furniture part is made from a hard material, this dowel core deforms inwardly, and when the furniture part is made from a soft material, the dowel core springs inwardly to a lesser extent. Thus, an increased, even hold is obtained in various materials such as hardwood, MDF, chipboard, softwood etc., since a constant closing pressure is applied to the actuating device and thus between the fastening device and the furniture part for different materials. The effect on the material tolerances of the furniture part is similar—some parts of the same material are somewhat harder, some are somewhat softer—this no longer has a negative effect on the hold of the furniture fitting in the furniture part. 
     Further advantageous embodiments of the invention are defined herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention will now be described in more detail with reference to the description of the figures below made with reference to the embodiments illustrated in the accompanying drawings in which: 
         FIG. 1   a  shows a perspective exploded view of a furniture fitting; 
         FIG. 1   b  shows a sectional front view of the fastening device of a furniture fitting; 
         FIG. 2   a  shows a side view of an open fastening device; 
         FIG. 2   b  shows a side view of a closed fastening device; 
         FIG. 3   a  shows a section through the drilled hole of a furniture part with an open fastening device; 
         FIG. 3   b  shows a drilled hole of a furniture part with a closed fastening device; 
         FIG. 4  shows a perspective view of a furniture part with furniture fittings. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1   a  shows a furniture fitting  2  for a furniture part  13  (not shown), which is provided with a fastening device  1  that is inserted into two drilled holes  14  (not shown) of a furniture part  13 . In this embodiment, the fastening device  1  has two dowel cores  3  and two dowel sleeves  4 , which can be inserted into two drilled holes  14  of a furniture part  13 . A spacer disk  12  is arranged between the dowel core  3  and the fastening flange  10  of the furniture fitting  2 . Because of the pins  15 , the dowel sleeve  4  can be drawn by the actuation device  5  in the direction of the fastening flange  10 . The dowel core  3  has a longitudinal slit  6  that runs axially and continuously through the dowel core  3  and thus forms a cylindrical spring core sleeve. The material of the dowel core  3  and the dowel sleeve  4  is preferably a metal, most preferably spring steel. In a preferred embodiment, it is advantageous if the dowel sleeve  4  is formed from C67 spring steel and the dowel core  3  is formed from C60 spring steel. If the dowel sleeve  4  is drawn in the direction of the fastening flange  10  by means of the actuating device  5 , then it is expanded by means of the dowel core  3 , thus resulting in fastening the furniture fitting  2  in the drilled holes  14  of a furniture part  13  (see  FIGS. 1   b  and  3   b ). Also in this embodiment, the dowel core  3  is arranged on the fastening flange  10 . Between the dowel core  3  and the fastening flange  10  is a spacer disk  12 , wherein a portion of the spacer disk  12  projects into the fastening flange  10  and another portion projects into the drilled hole  14 . Thus, the spacer disk  12  can accommodate lateral forces—inter alia when the furniture part  13  is under load—and thus on the one hand stabilizes the dowel core  3  and on the other hand, it results in less deformation at the fastening flange  10 , giving the system as a whole an increased draw. In this embodiment, the spacer disk  12 , which is preferably provided with a dog  18 , slots into the fastening flange  10  and thus is detachably fastened to the fastening flange  10 . In this embodiment, the dowel sleeve  4  is constructed as a single piece, but in another embodiment the dowel sleeve  4  may also be formed from several parts. 
       FIG. 1   b  shows a furniture fitting  2  arranged in the drilled holes  14  of a furniture part  13 . In this case, the fastening device  1  of the furniture fitting  2  is arranged in two drilled holes  14  which outlie the drilled hole  16  of the hinge cup  11 . 
       FIG. 2   a  shows a furniture fitting  2  with a fastening device  1  with which the furniture fitting can be fastened in a furniture part  13  (not shown). In this case the fastening device  1  has an actuating device  5 , which in this embodiment is formed as a hinged lever. In this case the dowel sleeve  4 , which can be drawn by means of said lever, outlies the hinge cup  11 . 
     Thus, as can be seen in  FIG. 2   a , when the actuating device  5  is hinged into a horizontal position, as shown in  FIG. 2   b , then the dowel sleeve  4  is drawn by said actuating device  5  in the direction of the actuating device  5  and thus expands on the dowel core  3 . 
       FIG. 3   a  shows a section through a furniture part  13  and its drilled holes  14 . In this drilled hole  14  there are only the dowel core  3 , the spacer disk  12  and the dowel sleeve  4 . The optional spacer disk  12  sits on the dowel core  3  and, when the dowel housing  4  is drawn over the dowel core  3 , this means that the dowel core  3  is deformed less at the fastening flange  10 , resulting in improved transmission of forces in the system as a whole. 
     In this embodiment both the dowel core  3  and the dowel sleeve  4  are constructed such that they are radially resilient and primarily consist of a metallic material. In addition, they have longitudinal slits; in this embodiment, the dowel core  3  is provided with a continuous longitudinal slit  6  (not shown) and the dowel sleeve  4  is provided with a plurality of discontinuous longitudinal slits. Both the dowel core  3  and the dowel sleeve  4  are provided with a plurality of axially offset inclined surfaces  7 ,  7 ′,  7 ″,  8 ,  8 ′,  8 ″. The term “axial direction” in this case means in the direction of the longitudinal axis of the drilled hole  14 , which corresponds to the insertion direction of the dowel core  3  and the dowel sleeve  4  of the fastening device. Thus, the shape of the inner sheath surface  9  of the dowel sleeve  4  is essentially—in cross-section—corrugated, and the shape of the outer sheath surface  9 ′ of the dowel core  3  is essentially—in cross-section—corrugated, wherein these two corrugated sheath surfaces  9 ,  9 ′ match each other. 
       FIG. 3   b  shows a dowel core  3  and a dowel sleeve  4  of a fastening device  1  as just described for  FIG. 3   a , with the exception that in  FIG. 3   b  the fastening device  1  has been actuated using the actuating device  5  (see  FIG. 2   a  and  FIG. 2   b , as it is not shown here). In this case, it is still only the dowel core  3  and the dowel sleeve  4  of the fastening device  1  that project into the drilled hole  14  of the furniture part  13 , and the dowel core  3  is still provided with an optional spacer disk  12 , which can accommodate lateral forces on the furniture fitting  2  when it is under load in order, inter alia, to result in less deformation of the dowel core  3  at the fastening flange  10 . 
     By actuating the actuating device  5  (not shown), the dowel sleeve  4  is drawn in the direction of the fastening flange  10  and is expanded on the dowel core  3 , thereby anchoring the fastening device  1  in the drilled hole  14  of the furniture part  13 . Since the inclined surfaces  7 ,  7 ′ of the dowel core  3  match the inclined surfaces  8 ,  8 ′ of the dowel sleeve  4 , essentially even expansion of the dowel sleeve  4  occurs at a plurality of axially offset locations. This continuous expansion of the dowel sleeve  4  means that material tolerances of the furniture part  13 —some parts of the same material are somewhat harder, some are somewhat softer—are evened out and thus they do not have a negative effect on the hold of the furniture fitting  2  in the furniture part  13 . Furthermore, the radially resilient dowel core  3  ensures that the hold of the furniture fitting  2  in various materials used to make the furniture part  13 , such as hardwood, MDF, chipboard, softwood etc., is good, since when a hard material is used to make the furniture part  13 , the resilient dowel core  3  deforms inwardly to a greater extent, but in contrast when a softer material is used to make the furniture part  13 , the resilient dowel core  3  deforms to a lesser extent. Thus, independently of the material, a constant load is transmitted from the fastening device  1  to the furniture part  12  and nevertheless ensures sufficient hold of the furniture fitting  2  in the furniture part  13 . 
     Both in the expanded condition and in the relaxed condition, the dowel core  3  and the dowel sleeve  4  are in constant surface contact, meaning that when the furniture part  13  is dynamically loaded, the resilient dowel core  3  keeps the fastening device  1  pressed against the furniture part  13  and thus the hold of the furniture fitting  2  in the drilled hole  14  of the furniture part  13  under load is enhanced. 
     By means of the continuous expansion, i.e. because the dowel sleeve  4  is expanded not just at its lower end, but the expansion occurs evenly along its sheath surface, then load transmission can also occur with drilled holes  14  of a furniture part  13  that are “too big”, and an enhanced hold is ensured, as with regular drilled holes  14 . 
     Furthermore, because even in the relaxed condition the dowel sleeve  4  and the dowel core  3  are in constant surface contact with each other, the fastening device  1  is held in its position, which means that it is possible to insert the furniture fitting  2  and its fastening device  1  easily into the drilled hole  14  of a furniture part  13 , meaning that the furniture fitting  2  can be rapidly mounted in the furniture part  13 . 
     Such a fastening device  1  thus has the positive effect of guaranteeing both a good hold of a furniture fitting  2  in various materials used to make a furniture part  13  and also that the material tolerances of the furniture part  13  do not have a negative effect on the hold of the furniture fitting  2 . Furthermore, the force required to actuate the actuating device  5  is kept small, since the resilience of the dowel sleeve  4  and the dowel core  3  has a positive influence on force transmission. 
       FIG. 4  shows an item of furniture  17  with a furniture part  13 , on which a furniture fitting  2  is applied by means of a fastening device  1 . 
     Even though these embodiments show the fastening device  1  exclusively outlying the hinge cup  11 , this should not be taken to constitute a restriction. Such a fastening device  1  may also be fastened in any drilled hole of a furniture part  13  in order to fasten a furniture fitting  2  in a furniture part  13 . 
     The illustrated embodiments of fastening devices for furniture fittings used on furniture parts are clearly not limiting in nature, but are simply individual examples of the many possibilities in embodying the inventive concept in a fastening device for furniture fittings. 
     List of reference numerals:
           1  fastening device     2  furniture fitting     3  dowel core     4  dowel sleeve     5  actuating device     6  longitudinal slit     7 ,  7 ′,  7 ″ inclined surface of dowel core  3       8 ,  8 ′,  8 ″ inclined surface of dowel sleeve  4       9  inner sheath surface of dowel sleeve  4       9 ′ outer sheath surface of dowel core  3       10  fastening flange     11  hinge cup     12  spacer disk     13  furniture part     14  drilled hole     15  pin     16  drilled hole for hinge cup  11       17  piece of furniture     18  dog on dowel core  3