Patent Publication Number: US-2010127446-A1

Title: Device for Hidden and Re-Detachable Connections, and Tools for the Assembly Thereof

Description:
The present invention relates to a device for invisibly and detachably connecting two surfaces whereof at least one surface belongs to a mobile workpiece and which comprises at least two interlocking connecting elements, whereof a first connecting element is to be arranged on the workpiece and a second one is to be arranged on the surface to which the workpiece is to be attached. Furthermore the invention relates to tools for mounting this device, i.e. a marking gauge, a pair of clamping tongs, a securing key and a marking tool. 
     Cup shaped connecting elements to be arranged in drilling holes are known from CH 662 599 of the same applicant. They are used to mount workpieces like veneered or coated panel units and wall coverings. Furthermore to fit the outer half of entry doors or sound-absorbing doors. Ultimately there are hardly any limits to the possible uses. Generally these connecting elements have proven themselves to be excellent. In practice it has been shown, however, that there is an increasing amount of uses where surfaces need to be connected to each other but where the previous connecting elements cannot be attached at all or only with great difficulty. This is the case, for example, for lightweight building boards with honeycomb structure. In the honeycomb core the connecting elements do not have sufficient stability nor can they be screwed on. Based on this realization, the objective of the invention is to create a device for invisible and detachable connections which keep the above mentioned problems from occurring. Furthermore, a marking gauge for exact mounting of the device is described, as well as special clamping tongs for clamping the device to a surface, a securing key for depressing securing tabs and a marking tool for determining the orientation of the device. 
     The device according to the invention corresponds to the characteristic features of patent claim  1 . The marking gauge is described in patent claim  18 , the clamping tongs in patent claim  23 , the securing key in patent claim  27  and the marking tool in patent claim  29 . Further advantageous embodiments of the inventive idea are apparent from the dependent patent claims. 
    
    
     
       Hereinafter preferred exemplary embodiments of the invention are specified by means of the drawings. 
         FIGS. 1-3  show a view and partial views of a device with a connecting element, 
         FIGS. 4-5  show a sectional view along line A-A of the device and of the connecting element according to  FIG. 1 , respectively, 
         FIGS. 6-9  show a sleeve for receiving the connecting element according to  FIGS. 1-5 , 
         FIGS. 10-13  show a marking gauge for mounting the device according to  FIGS. 1-9 , 
         FIG. 14  shows clamping tongs for mounting the device according to  FIGS. 1-9 , 
         FIGS. 15-16  show a securing key for mounting the connecting element according to  FIGS. 1-5 , 
         FIGS. 17-18  show a marking tool for mounting the device according to  FIGS. 1-9 , 
     
    
    
     To mount a workpiece  1  to a surface  2 , two interlocking connecting elements  3  and  4  are provided. Of those, for example can-shaped connecting elements  3  and  4 , a first connecting element  3  is to be arranged on a workpiece  1  and a second connecting element  4  is to be arranged on a surface  2 . This second connecting element is marked in  FIG. 4  by a dotted line. To arrange the connecting elements  3  and  4  on the workpiece  1  and on the surface  2 , respectively, a recess  5  and  6  is placed at a predetermined location into the workpiece  1  and the surface  2 , preferably by use of a drill. To fit these recessions  5  and  6  exactly on top of each other, a marking gauge with a center point is placed into the first drilled recess  5  or  6 , as described in the state of the art mentioned in the beginning. The work piece  1  is then pressed in the right position against surface  2  so that the center point leaves a depression which will serve as mark for drilling the second recess  5  or  6 . This ensures that the recesses  5  and  6  and the connecting elements  3  and  4  to be arranged therein will be placed exactly on top of each other. The newly developed marking gauge will be explained later. 
     According to the invention, the connecting elements  3  and  4  comprise at least one locking device  8  according to  FIGS. 1 to 5  which has the purpose of clamping or gripping the respective connecting element  3  or  4  in place. This can be accomplished either directly inside the recess  5  or  6  of the workpiece  1  or the surface  2  or—as is the case in the present embodiment—in an additional sleeve  9  which receives the respective connecting element  3  or  4 . An example of a sleeve  9  is shown in detail in  FIGS. 6 to 9 . The sleeve  9  can itself comprise at least one locking device  10  for clamping it securely inside the recess  5  or  6  of the workpiece  1  or the surface  2  respectively. As can be seen especially in  FIG. 9 , the sleeve  9  can comprise a flange. This flange can rest on surface  2  as shown. Depending on the material structure of the surface  2 , a mounting with a countersunk flange is also possible. 
     In the embodiment according to  FIGS. 4 and 5  the locking device  8  of the connecting elements  3  and  4  comprises a latch element  11 . It comprises at least one projection  12  designed to engage with the sleeve  9  and/or with the recess  5  or  6  of the workpiece  1  or the surface  2  respectively. The latch element  11  shown here can be slideably moved against the force of a spring  13  which presses the projection  12  into the wall of the sleeve  9  and/or into the wall of the recess  5  or  6 . In the present case the wall of the sleeve  9  comprises at least one engaging site  14  for each projection  12 , for example in form of a notch or a punching. Preferably the locking device  8  or its latch element  11 , respectively, are secured against accidental release. The latch element  11  can, for example, comprise a bar  15  which, after pushing it down according to the arrows, rests against a stationary locking element  16 . The locking element  16  can be formed in a step-like manner as shown, so that the latch element  11  is freely movable prior to being pushed down against the force of the spring  13  as mentioned above. Due to the bevel of the projection  12  (also shown), the latch element  11  is pushed back when the connecting element  3  or  4  is inserted into the sleeve  9  and doesn&#39;t snap into place until it reaches the area of the engaging site  14 . The locking devices  10  of the sleeve  9  are, for example, hook or claw shaped. A crossectional straight shape is also possible but less effective. They can be punched out of the wall of the sleeve  9  and/or be formed from it. By bending they can be moved into the desired locking position. Because only the wall of the sleeve  9  or its respective engaging site  14  is necessary for fastening the connecting element  3  or  4 , the sleeve  9  can also be designed without bottom and with perforated walls. In theory a design with multiple parts is possible but less sensible. The term sleeve  9 , therefore, needs to be understood comprehensively. 
     Marking gauge  17  is provided to mount the connecting elements  3  and  4  in their respectively correct position. It is shown in  FIGS. 10 to 13 . A perfectly round marking gauge with a center point is know from CH 662 599 mentioned in the beginning. If the diameter of recess  5  or  6 , in which the marking gauge is to be inserted, is only slightly bigger, the marking gauge slides around in this recess  5  or  6  leading to inaccuracies when marking. The result may be that the workpiece  1  can not be mounted, because absolute accuracy is necessary. Another disadvantage of the previous marking gauge is that it can fall out of recess  6  when working on a vertical wall. Furthermore the center point can get caught and therefore tilt when aligning the workpiece  1 . The mark can, therefore, be placed in the wrong position without this being noticed. Lastly, the known marking gauge cannot be used especially with lightweight building boards with honeycomb structure. It will not find sufficient stability in the honeycomb core. 
     With the marking gauge  17  according to the invention these disadvantages are effectively prevented. It is not just inserted into the recess  5  or  6  but is securely fastened therein. For this purpose it comprises a clamping device  18 . In the present exemplary embodiment this device causes claws or points  19  to be pressed into the wall of recess  6 . See  FIG. 10  and  FIG. 13 , showing a sectional view along line B-B in  FIG. 10 . When inserting the marking gauge  17 , the handle parts  20  are pressed together. They are pushed apart by at least one spring  21 . See also  FIG. 10  and  FIG. 12 , showing a sectional view along line A-A in  FIG. 10 . After releasing the handle parts  20 , the claws or points  19  hold the marking gauge  17  immovably in place in the recess  6 . In lightweight building boards the claws or points  19  open to the extent that the clamp element  22  above the claws or points  19  rests against the surface layer  23  of the lightweight building board and holds the marking gauge  17  in place. The only requirement is a surface layer  23  of sufficient wall thickness, for example, depending on the material,  0 . 8 mm. The center point  24  can, for example, be designed to be adjustable from the back regarding its height and penetration depth. In the present case it is screwable with an Allen wrench. The center point  24  can comprise a slightly dull end  26 . Thus workpiece  1  can be moved during positioning without being caught immediately by center point  24 . The desired mark is formed only when workpiece  1  is pressed against it. Slight inaccuracies of recess  6  are compensated by marking gauge  17  according to the invention. Working on a vertical wall and even on a ceiling are now possible without any problems. A tilting of the marking gauge  17 , leading to wrong marks, is not possible anymore as well. 
     Due to the marking gauge  17 , the second recess  5  or  6  can be placed with an exact fit to the position of the first recess  5  or  6 . After that the connecting elements  3  and  4  or—as in the present example—the respective sleeve  9  can be inserted. To align these exactly, a marking tool  27  according to  FIGS. 17 and 18  can be used. With the marking tool  27  the absolutely necessary alignment of connecting elements  3  and  4  to each other can be ensured. In the embodiment shown in the drawing a sleeve  9  is inserted first, therefore its alignment needs to be established. For this purpose the marking tool  27  comprises a peg  28  which fits into the recess  5  or  6 . The peg  28  in the present example is arranged offset to one side on the marking tool  27 . In any case the marking tool  27  comprises an edge  30  which extends the axle center  29  of the peg  28  at least in one direction. Along this edge  30  the axle center  29  at the edge of recess  5  or  6  can be extended or marked with a commercially available scriber. The sleeve  9  can then be easily positioned in such a way that their markings  31  are placed exactly in the marked axle center  29 , because the markings  31  themselves indicate the axle center of the sleeve  9 . In the present example the markings  31  are comprised of one indentation each on the circumference of the sleeve  9 . This has the advantage that the markings  31  are clearly visible but will not damage the workpiece  1  or the surface  2  when the sleeve  9  is inserted. Projections or any other kind of marking would also be possible, for example, by merely scratching the flange of the sleeve  9  through the indentation but not piercing it. Accordingly the connecting elements  3  and  4  can have a marking  31 , especially in the case of being inserted without the sleeve  9 . 
     After aligning the sleeve  9  in the desired way it can be clamped in place in recess  5  or  6  using the locking device  10 . The most simple and secure way to achieve this is by using clamping tongs  32  according to  FIG. 14 . The clamping tongs  32  are designed in such a way that, when the handles  33  are pushed together, the two jaws  34  are pushed apart so that two locking devices, positioned in opposition to each other, are pushed into the wall of recess  5  or  6 . Preferably the leading guide  35  of one of the jaws  34  is designed in such a way that the jaws  34 , inserted through the width of the recess  5  or  6 , can be pushed apart far enough that they reach beyond that width and can, for example, reach behind the surface layer  23  of a surface  2  comprised of a lightweight building board. Preferably the jaws  34  are not only pushed apart to this purpose but guided some distance around the surface layer  23  to reach behind it. Thereby the locking devices  10 —if this is necessary, especially for lightweight building boards with especially weak core—can be pivoted far enough around so that they can grip to the surface layer  23  from behind. For this purpose the guide  35  can comprise an intermediate part  37  linked with both an extension  36  of handle  33  and the jaw  34 . In the present example the joint  38  connecting the intermediate part  37  with the jaw  34  is formed as a bolt and is guided as a curve in a crank  39 . Other embodiments are possible, for example with a rail. It is essential that the radius of the curved crank  39  is selected in such a way that the locking device  10  can be reliably pivoted into the locking position without risk of being damaged. With the shown clamping tongs  32 , two locking devices  10  positioned in opposition to each other can be activated at the same time. Therefore, with two movements of the clamping tong, a sleeve  9  with four locking devices  10  can be reliably clamped in place in the recess  5  or  6 . 
     Then the connecting element  3  or  4  can be easily inserted into the sleeve  9  until it snaps in place in the position predetermined by the correct position of the sleeve  9 . For comfortable and secure activation of the fastener of latch element  11  of locking device  8 , as has been already explained by means of  FIG. 4 , a special securing key  40  according to  FIGS. 15 and 16  is used. This tool comprises a handle  41  with a fork  42  with two or more teeth  43 . Its free end can comprise an engaging part  44  which fits into a matching recess  45  of the latch element  11  of locking device  8 ; see  FIG. 1 . A bevel  46  adjacent to the engaging part  44  ensures that the bar  15  of the latch element  11  is pushed into the secure position, as can be seen on the left side of fig. and  4 . Therefore, in case of a connecting element  3  or  4  with four locking devices  8  it is sufficient to press or tap the securing key  40  twice to fasten the connecting element  3  or  4  so securely in the sleeve  9  that it will not be loosened even when exposed to strong shocks or vibrations. It is self-evident, that a fork  42  with four teeth  43  positioned in pairs in opposition to each other would be possible whereby all four locking mechanisms  8  could be reached at the same time with one single use of the securing key  40 . 
     According to the known state of the art, the connecting elements  3  and  4  can, according to  FIGS. 4 and 5 , comprise one hook  47  each, preferably a wedge hook. The connecting elements  3  and  4  are then each turned  180  degrees and arranged to each other in such a way that the hooks  47  can interlock. The connecting elements can furthermore designed in such a way that the hooks  47  can each only grip towards the center which requires that, for example, guiding bars on the connecting element  3  and/or  4  are to be provided. If the guiding bars are omitted, workpiece  1  remains movable sideways towards surface  2  to a certain degree which can be useful in some specific cases. To increase the load values of the connecting elements  3  and  4  a reinforcement element  48  can be inserted at the hook  47 , made, for example, from metal. It can be attached by pressing or gluing. 
     Depending on the material of the workpiece  1  and especially the surface  2  and depending on the desired load value, an additional gluing of the sleeve  9  might be appropriate, for example with a two-component adhesive. For applying the adhesive, at least one opening can exist at the bottom of the sleeve  9 , preferably, however, at the flange-shaped edge; see especially  FIG. 8 . Thereby the locking device  10  can be backfilled and a bigger pressure surface can be created. 
     Furthermore, due to the screwless mounting, it is possible to form the walls and the bottom of the connecting elements  3  and  4  in a closed or closeable manner. Possible perforations, resulting from the production of the connecting elements  3  and  4 , can be closed with a closure  49 . The closure can be designed in any desirable way. In this way the penetration of moisture through the walls or the bottom of the connecting elements  3  and  4  can be avoided. Moisture can often damage the unwaterproof core of workpiece  1  and even lead to the separation of veneer. 
     It is in the scope of the invention to design the described parts of the device and the tools differently than shown in the drawings. Connecting elements  3  and  4  could be provided insertable without the sleeve  9 . The locking device  8  of the connecting elements  3  and  4  could be designed according to the locking device  10  of the sleeve  9  and be activated with the clamping tongs  32 , if the geometry of the connecting devices  3  and  4  is adjusted accordingly. The connecting devices  3  and  4  or the sleeve  9  can comprise at least one insert of insulating, sound-absorbing and/or fire-retarding material on either side of its bottom. 
     The device according to the invention can be used in wood construction, especially in interior construction, store construction, furniture construction, door construction etc. Also in exhibition stand construction and in ship and metal construction. Elements of, for example, solid wood, sheet material, wall coverings, facings, sidings, decorative elements etc. can be mounted in that way. The device is especially useful when one of the surfaces to be connected is a lightweight building element.