Patent Publication Number: US-2007107640-A1

Title: Table having at least two cantilever extensions hinged on to a fixed table top

Description:
The present invention refers to an extensible table, which is provided with at least two cantilever extensions coupled to a fixed table top by hinging means. In a table of this kind, the extensions, when in the retracted condition thereof, are suspended under the fixed table top, whereas, when extracted, they enable the available surface of the table to be increased by extending it in one or more directions.  
      The most relevant state of the art in this connection is represented by the international patent application filed by this same Applicant, and published under No. WO-A-02 054 908, in which both the fixed table top and the extensions of a table are made out of thick crystal (tempered glass) panes having mutually opposed, parallel section planes that are inclined relative to the useful surface. The hinges have their axes extending orthogonally to said section planes and enable the extensions to be extracted and retracted by a simple 180°-rotation.  
      In particular, each one of the hinges in the second embodiment described in the above-mentioned prior-art disclosure comprises a bushing that is firmly joined to a wing attached to the lower face of an extension. This bushing is capable of rotating between two head pieces that are firmly joined with each other, one of said piecese being secured to the lower face of the fixed table top.  
      Since there is nothing to actually prevent an extracted extension from retracing under a horizontal force being exerted thereagainst, quite clear is the drawback that may derive if a force of this kind is unintentionally exerted when the surface of a extracted extension is being used, e.g. by a person sitting at the table while having a meal.  
      It therefore is a main object of the present invention to provide an extensible table that is an improvement of the above-mentioned prior-art table, in that it is provided with means adapted to ensure full stability of the table extensions when in their extracted configuration.  
      In accordance with this object of the present invention, the hinges used to support the extensions have been given a construction that partly differs from the previously used design, while however further ensuring an unaltered level of convenience for the user in protracting and retracting the extensions themselves.  
      These and further objects of the present invention are reached in a table having the features and characteristics recited in the appended claims, as this will be more readily understood from the description that is given below by way of non-limiting example of embodiment with reference to the accompanying drawings, in which:  
       FIG. 1  is a side, partially sectional view of the contiguous portions of the fixed table top and an extension, along with the related hinge, in a table shown in the configuration corresponding to an extracted extension;  
      FIGS.  2  to  4  are views illustrating the operating sequence of the hinge when bringing the extension from the extracted configuration shown in  FIG. 1  into the retracted configuration thereof,  
       FIGS. 5 and 6  are views illustrating the operating sequence of the hinge when bringing the extension from its retracted configuration shown in  FIG. 4  into its extracted configuration shown in  FIG. 1 ;  
       FIG. 7  is a view of a detail of the hinge that is part of the table. 
    
    
      In  FIG. 1 , which relates to a table according to the present invention, the following parts are illustrated:  
      a fixed table top  10 , made out of a crystal, i.e. a tempered glass pane having preferably a wall thickness of approx. 15 mm, wherein the upper and lower faces of which are indicated at  12  and  14 , respectively. The fixed table top  10  (of which only the portion terminating with a section plane  16  inclined downwards towards the centre of the table are shown) actually, rests on a rigid support structure which, owing to its having no direct relevance to the present invention, is not shown in the Figure, but can for instance be the same as the one disclosed in the above-discussed patent application WO-A-02 054 908, to which reference is made for further details;  
      an extension  20 , which is itself made out of a crystal or tempered glass pane having the same wall thickness as the fixed table top  10 , wherein the upper and lower faces thereof are indicated at  22  and  24 , respectively. The extension  20  is supported in a cantilevered manner by the fixed table top  10  with the aid of articulated support means that shall be described in greater detail further on. The extension  20  has a section plane  26  that is adapted to move into abutting against the corresponding section plane  16  of the fixed table top  10  when the extension is in the extracted configuration thereof so that it is inclined and parallel to the same section plane  16 . On the lower face  24  of the extension  20 , very close to the section plane  26 , there is attached (e.g. bonded with the use of a silicone-based adhesive) a disc  30  having two vertical wings  32  to receive a stud  34 , which is part of the afore-mentioned articulated support means, and the horizontal axis X of which is parallel to the section planes  16  and  26 . Onto this disc  30 , in a position that is closer to the section plane  26  of the extension  20  than the stud  34 , there is finally screwed the stem  36 —extending orthogonally to the faces  22  and  24  of the same extension  20 —of a first retaining member  35  that further comprises a head  37 . This head is in the shape of substantially a triangular prism having a base  38  parallel to said faces of the extension  20  and—at a certain distance from said base—an undercut  39 ;  
      a hinge, which is generally indicated at  100  and a also part of the aforementioned articulated means provided on the fixed table top  10  as a support for the extension  20 , the axis Z thereof being orthogonal to the section planes  16  and  26 . The hinge  100  comprises:  
      a cylindrical bushing  110 , inside which there is housed a spring  112  extending along a diameter of the same bushing. To this spring  112  there are attached two small terminal blocks  114  serving the purpose of retaining the spring between a pair of longitudinal grooves (not shown, for a better clarity) of the cylindrical bushing  110 . From the outer surface of the bushing  110  there extends a wing  116 , whose upper and lower faces are indicated at  118  and  119 , respectively. On the free end portion  117  of the wing  116  the stud  34  supporting the extension  20  is mounted in a freely rotatable manner about the horizontal axis X. A pair of adjacent slots  120  and  122  are further provided, in a central position, on the wing  116 . The first slot  120  has a larger size than the second slot  122  and comprises a narrower appendix  124  facing the stationary top surface  10  of the table. This appendix  124 —whose shape can be seen in  FIG. 7 , which is a partial top view of the wing  116 —is not a fully open, i.e. of through-passing design, but is only open on the upper face  118  of the wing  116 ; however, it is connected via a hole  126  having a circular cross-section with the second, narrower slot  122  that opens on the lower face  119  of the wing  116  only. A second retaining member  130  is associated to the wing  116 , the said member  130  comprising a mushroom-shaped head  132 , a stem  134 , a retaining spring  136  and a small terminal block  135 . Specifically, the head  132  is adapted to be received in the appendix  124  of the first, larger slot  120 , whereas the stem  134  is adapted to slide, jointly with the small terminal block  135  screwed on to the stem  134 , through the hole  126  connecting the two slots  120  and  122  with each other. To the lower face  119  of the wing  116 , below the second retaining member  130 , there is attached a third retaining member  140  comprising a piston capable of sliding, in a direction parallel to the wing  116 , in a sleeve  138  provided with a slit  139  in correspondence to the aperture of the second slot  122 . The head  142  of this piston is flattened and inclined downwards under the corresponding aperture of the first slot  120 , and the piston itself is biased by an opposing spring  144 , whose tension can be adjusted by means of a nut  146  screwing on the stem  148  of the same retaining member  140 . Unlike all other above-described parts, which are preferably made of stainless steel, the springs  112 ,  136  and  144  are made of music wire;  
      a first disc  150  that retains the spring  112  housed in the bushing  110  from above and has a perfectly smooth and flat upper face  152  so as to enable it to be properly attached, e.g. by bonding with a silicone-based adhesive, to the lower face  14  of the fixed table top  10 ;  
      a second disc  160  that is rigidly coupled to the first disc  150  by means of screws (not shown for reasons of greater simplicity) provided inside the bushing  110 , in order to ensure that the same bushing  110  is capable of rotating about the axis Z, as this shall be explained in greater detail further on.  
      When the extension  20  is to be brought into its retracted position from the extracted configuration thereof shown in  FIG. 1 , the mode of operation of the above-described arrangement is as follows. In the extracted configuration shown in  FIG. 1 , the section planes  16  and  26  are abutting against each other, while the head  37  of the first retaining member  35  is housed within the first slot  120  and, owing to the base  38  of the same retaining member  35  lying below the head  132 , keeps the second retaining member  130  in a raised position. The third retaining member  140  is in turn in such a position as to cause the head  142  thereof to lie in correspondence to the aperture of the first slot  120  in the lower face  119  of the wing  116 .  
      Now, in order to retract the extension  20 , the user must grasp the free end portion thereof with his/her hands and lift it, i.e. rotate it anti-clockwise about the horizontal axis X by making use of the connection between the stud  34 , which is associated to the extension  20 , and the wing  116 , which is associated to the fixed table top  10 . In this way, the head  37  of the first retaining member  35  moves away from the second retaining member  130 , thereby displacing downwards so as to move through the entire thickness of the extension and slip out of the lower face  119  of the wing  116 . Towards the end of this displacement thereof, the head  37  of the retaining member  35  strikes against the inclined head  142  of the third retaining member  140 , which is in this way pushed towards the fixed table top  10 —see  FIG. 2 .  
      At the end of said displacement, the head  142  of the third retaining member  140  eventually abuts against the undercut  39  provided on the head  37  of the first retaining member  35 , thereby positively preventing the extension  20  from being capable of rotating about the horizontal axis any further—see  FIG. 3 .  
      Upon reaching this position, the user pushes the extension  20  to turn relative to the fixed table top  10  by 180° about the axis Z, since the bushing  110  of the hinge  100  is capable of turning jointly with the wing  116  relative to the discs  150  and  160 , while however maintaining unaltered the arrangement of the retaining members  35 ,  130 ,  140  relative to each other, as well as the arrangement of the stud  34  on the wing  116 . At the end of this rotation, the extension  20  lies in its retracted configuration, i.e. under the fixed table top  10 —see  FIG. 4 .  
      When on the contrary the available top surface of the table has to be enlarged, i.e. the extension  20  has to be pulled out from the retracted position thereof under the fixed table top (configuration illustrated in  FIG. 4 ) and brought into its extracted configuration, the user must first of all rotate the extension  20  with the bushing  110  of the hinge  100  by 180° relative to the fixed table top  10  about the axis Z in the opposite direction and in the reverse order with respect to the afore-described procedure, while anyway keeping unaltered the arrangement of the retaining members  35 ,  130 ,  140  relative to each other, as well as the arrangement of the stud  34  on the wing  116 . At the end of this rotation, the extension  20  and the hinge  100  will lie in the configuration shown in  FIG. 3 .  
      To bring the extension  20  into the extracted configuration thereof the user must at this point grasp the free end portion thereof with his/her hands and lift it further, i.e. rotate it anti-clockwise on the stud  34  about the horizontal axis X up to the point at which the lower edge of the section plane  26  of the same extension  20  comes to touch the upper face  118  of the wing  116 . This rotation is made possible by the stud  34  cooperating with the wing  116  and results in the head  37  of the first retaining member  35  disengaging from the head  142  of the third retaining member  140 . This disengagement is permitted by the displacement of the piston  140  caused by the action of the biasing spring  144 , and it in turn enables the second retaining member  130  to slide downwards within the connecting hole  126  and the narrower slot  122  of the wing  116 . This sliding motion comes to an end when the head  132  of the same second retaining member  130  lies fully within the appendix  124  of the larger slot  120  of the wing  116 —see  FIG. 5 .  
      Finally, the user lowers the extension  20 , i.e. rotates it clockwise on the stud  34  about the horizontal axis X, and this results in the head  37  of the first retaining member  35  moving upwards within the slot  120  of the wing  116 —see  FIG. 6 . The lowering movement of the extension  20  comes of course to an end when the section plane  26  thereof eventually abuts against the section plane  16  of the fixed table top and the base  38  of the first retaining member  35  lies again under the head  132 , so as to keep the second retaining member  130  in a raised position—see again  FIG. 1 . It is exactly the first retaining member  35  interacting in this way with the second retaining member  130  that is effective in retaining the extension  20 , i.e. to make it stable and fixed in the extracted configuration thereof by preventing the same extension to accidentally retract under the action of a force exerted against it in a horizontal direction.  
      While the preceding description is referred to a preferred embodiment of the present invention, it will be appreciated that, within the scope defined by the appended claims, a number of other embodiments and variations thereof are possible. In particular, it shall be appreciated that the table may comprise any desired number of extensions, although such number is usually not higher than four when the fixed table top is square or rectangular in its shape, and not just a single extension as described above.