Abstract:
The present invention is used for placing and sticking holding elements to support surfaces. The holding elements are provided with connecting surfaces which are coated with a dry hot-melt-type adhesive on the bare side thereof. Said adhesive can be reactivated by means of heat treatment. The inventive device consists of a housing ( 1 ) having a receiving component ( 2 ) that is displaceably guided therein and is used for the holding element ( 3 ) as well as means for quickly heating the hot-melt-type adhesive, lowering the receiving component ( 2 ) and pressing the adherent ( 25 ) after the adhesive has been melt on. The invention is characterized in that heating is carried out by means of hot air (H) which is supplied passing the housing ( 1 ) and in that the receiving component ( 2 ) is surrounded by a closed wall ( 7 ) that extends from the hot air discharge location in the housing ( 1 ) to the holding element ( 3 ). The hot air (H) can thus be conveyed to the adhering hot-melt-type adhesive before or while the holding element ( 3 ) rests on the support surface ( 25 ) and holding elements ( 3 ) having a differently embodied adherent ( 25 ) consisting of either metal or synthetic material can thus be stuck to the support surface ( 32 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention pertains to a device for setting and bonding fasteners onto support surfaces, wherein the fasteners are provided with connecting surfaces, the exposed side of which is coated with a dry hot-melt adhesive that can be reactivated under the influence of heat. This device comprises a housing with a receiver part for the fastener that is movably guided in the housing, and a means for rapidly heating the hot-melt adhesive and lowering the receiver part, as well as pressing on the adhesion surface after the adhesive has melted.  
           [0002]    A device of this type for automatically setting holding bolts is known from WO 98/12 016. In this case, the holding bolts are placed on the support surface by a robot to be exactly perpendicular. The holding bolts are transported to the bolt receiver part through a feed channel and sufficiently heated by an induction coil surrounding the receiver part such that the hot-melt adhesive melts and the holding bolt can subsequently be pressed onto the support surface.  
           [0003]    This setting device is especially designed for holding bolts with circular discs and is only suitable for use with metallic bolts due to the inductive heating process. In addition, it is unsuitable for manual use because the adhesion surface needs to be placed on the support surface absolutely plane-parallel in order to achieve the desired bonding effect. The adhesive on the connecting surface of the fastener is unable to obtain the required contact with the support surface if the displacement axis of the housing is only slightly inclined relative to the support surface. In this case, the fastener would also not be arranged exactly perpendicular to the support surface such that secure mounting of a functional or structural component using the fastener would be jeopardized.  
         SUMMARY OF THE INVENTION  
         [0004]    The invention is based on the objective of designing a setting device of the initially described type such that it can be universally utilized for fasteners with adhesion surfaces and, if so required, can also be manually placed perpendicular to the support surface and securely held until the fastener is bonded to the support surface.  
           [0005]    In the setting device according to the invention, this objective is attained due to the fact that the heating process is realized by means of hot air that is supplied via the housing and directly conveyed to the hot-melt adhesive around the receiver part. The receiver part is surrounded by a closed wall that extends from the hot-air outlet in the housing up to the fastener.  
           [0006]    A rapid heating process can be realized because the hot air is directly conveyed to the hot-melt adhesive. In this case, it is important that the receiver part be surrounded by a closed wall that extends up to the fastener. This makes it possible to rapidly and securely attach fasteners that have differently designed adhesion surfaces and consist of metal or plastic.  
           [0007]    The design of the closed wall makes it possible to convey the hot air to the adhesion surface of the fastener in a directional fashion such that the adhesive melts as quickly as possible. The installation of a dome-shaped receiver head for holding the receiver part makes it possible to insert fasteners of different geometries into the receiver part and thus to broaden the scope of application of the setting device.  
           [0008]    The transversely extending bore provided makes it possible to convey cooling air to the end of the fastener that is inserted into the receiver part, such that heating is limited to the adhesion surface. In addition, the cooling air makes it possible to attract the end of the fastener that is inserted into the recess of the receiver part by suction, according to the Venturi principle, and to release this end of the fastener again by switching off the supply of cooling air.  
           [0009]    In order to allow the manual use of the setting device, it is practical, according to another characteristic of the invention, to connect the cylindrical body to three axially parallel support rods via a carrier plate. Due to these measures, the fastener that is clamped in the receiver part can be held in plane-parallel contact with the support surface while the adhesive is heated. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Two embodiments of the invention are described in greater detail below with reference to the figures. The figures show:  
         [0011]    [0011]FIG. 1, a perspective view of a setting device in the setting position on a support surface;  
         [0012]    [0012]FIG. 2, an enlarged sectional view of the head of the setting device before inserting the fastener;  
         [0013]    [0013]FIG. 3, the setting head with inserted fastener while setting the fastener onto the support surface;  
         [0014]    [0014]FIG. 4, the setting head after the setting process, namely while pressing the fastener onto the support surface;  
         [0015]    [0015]FIG. 5, a side view of a fastener with a threaded bolt and a circular disc that serves as the adhesion surface;  
         [0016]    [0016]FIG. 6, a side view of an alternative fastener with a rectangular adhesion surface;  
         [0017]    [0017]FIG. 7, a front view of the alternative fastener;  
         [0018]    [0018]FIG. 8, the setting head of the alternative fastener as the one shown in FIG. 2, wherein the receiver part for receiving a fastener is designed in accordance with FIGS. 6 and 7, after setting and pressing on the fastener;  
         [0019]    [0019]FIG. 9, the head of another setting device with inserted fastener, while heating the adhesion surface and the support plate;  
         [0020]    [0020]FIG. 10, the same head while pressing the fastener onto the support plate;  
         [0021]    [0021]FIG. 11, an enlarged detail of the head shown in FIG. 9, and  
         [0022]    [0022]FIG. 12, an enlarged detail of the head shown in FIG. 10. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    The device shown in FIG. 1 serves to manually place and bond fasteners on support surfaces, e.g., sheet metal of car bodies and household appliances, housing walls of electric appliances, window panes, or other support plates. In this case, the fasteners are provided with essentially planar connecting surfaces, the exposed side of which is coated with a dry hot-melt adhesive that can be reactivated under the influence of heat.  
         [0024]    The setting device essentially consists of an easily manageable housing  1  with the receiver part  2  for a fastener  3 , which is movably guided in the housing, driving means for lowering the receiver part  2  and pressing the fastener  3  onto the support surface  32 , and a hot-air blower that is arranged in the housing and serves to heat the hot-melt adhesive applied to the fastener  3 .  
         [0025]    The design of the setting device and its function are described in greater detail below, with reference to FIGS.  2 - 4 . FIG. 2 shows an enlarged representation of the lower part of the setting device, with a fastener  3  according to FIG. 5 clamped therein. FIG. 3 shows the receiver part  2  before attachment to the support surface  32 , and FIG. 4 shows this receiver part after attachment, while the fastener  3  is pressed onto the support surface  32 .  
         [0026]    [0026]FIG. 2 also shows that the lower end of the housing  1  is connected to a pipe section  4 , of reduced diameter, by means of an intermediate wall  5  that is tapered in the shape of a funnel. This pipe section is connected to a cylindrical body  6  at its lower end, wherein said cylindrical body is downwardly extended by a cylindrical outer wall  7 . A dome-shaped receiver head  8  with a central recess  9  for holding the receiver part  2  is situated within the cylindrical wall  7 . The receiver head  8  is connected to the ends of piston rods  11  by means of transverse braces  10 , wherein the piston rods are movably guided in bores  12  of the cylindrical body  6 . The piston rods  11  are guided in cylinders  13  that can be charged with compressed air via air inlet connections  14 . The cylindrical wall  7  ends underneath the receiver bead  8  in the form of a rim  15  that is directed inward in the shape of a funnel, and the inside diameter of which is slightly larger than the outside diameter of the holding head  8  such that this can be a lowered onto the support surface  32  in an unobstructed fashion through the hole in the inner rim  15 .  
         [0027]    The receiver part  2  contains a central recess  16  that is open toward the bottom and ends in the form of a transversely extending bore  17  at its upper end. One side of this bore  17  is connected to a ventilation pipe  18  that extends outward through a hole  19  in the dome-shaped wall  20  and through a vertically extending oblong recess  33  in the cylindrical outer wall  6 , and that is provided with an air inlet connection  21  for introducing external cooling air.  
         [0028]    On the side opposite from the ventilation pipe  18 , another hole  22  for discharging the cooling air introduced through the ventilation pipe  18  is arranged in the dome-shaped wall  20 . This simultaneously causes a suction effect, for attracting the inserted fastener  3 , to be generated in the recess  16  according to the so-called Venturi principle. The fastener may, for example, consist of a threaded bolt shown in FIG. 5.  
         [0029]    The threaded bolt usually consists of a threaded shaft  23  that can be connected to a structural component by means of a corresponding threaded receptacle, and of a circular disc  24  that is integrally formed onto the threaded shaft. On its exposed underside, this circular disc has an essentially plane connecting surface  25  that is coated with a dry hot-melt adhesive that can be reactivated under the influence of heat.  
         [0030]    According to FIG. 2, the fastener  3  that is realized in the form of a threaded bolt is inserted into the recess  16  of the receiver part  2  with its threaded shaft  23  and is initially held by friction, wherein the shaft diameter exactly corresponds to the clear inside diameter of the recess  16 . A supplementary suction effect for securely retaining the shaft  23  can be realized according to the Venturi principle by introducing cooling air through the ventilation pipe  18 .  
         [0031]    In order to also allow the manual use of the setting device, the cylindrical body  6  that is connected to the housing pipe section  4  is preferably also connected to axially parallel support rods  26 , the free ends of which contain funnel-shaped suction cups  27 . In order to ensure a stable support without shaking, a total of three support rods  26  are distributed around the circumference, wherein the upper ends of the support rods are rigidly screwed to a carrier plate  28  that, in turn, is rigidly connected to the cylindrical body  6  by means of bolts  29  that engage on both sides.  
         [0032]    The interior of the respective support rods  26  contains a bore  30  that extends downward into the suction cups  27  and ends in the form of a connection fitting  31  at its upper end. Suction lines, not shown, can be connected to these connection pieces  31  in order to generate a vacuum in the suction cups  27  after placing the device to the support surface  32 . In this case, the plane of contact “E” of the suction cups  27  is aligned exactly perpendicular to the displacement direction “V” of the receiver head  8 . This ensures, when lowering and pressing on the receiver head  8  in the direction of the arrows “A,” that the connecting surface  25  of the inserted fastener  3  is held in plane-parallel contact with the support surface  32  after the fastener is placed onto the support surface  32  (see FIG. 4), and in fact long enough that sufficient adhesive connection is produced. In this context, the term sufficient refers to a state in which a functional stability is reached that allows uncomplicated transport of the bonded part.  
         [0033]    The adhesion surface  25  is heated by means of hot air that is conveyed by a not-shown hot-air blower and that emerges from the reduced pipe section  4  of the housing  1 . The heating process takes place in two phases. In the first phase, or so-called pre-heating phase, the hot air is, after insertion of the fastener  3 , conveyed to the hot-melt adhesive on the connecting surface  25  around the receiver head  8  according to the broken lines “H” as indicated in FIG. 2, namely before attachment to the support surface  32 . This pre-heating phase may require a few seconds.  
         [0034]    The second phase of the heating process begins after positioning and placing the setting device at the predetermined location on the support surface  32 . FIG. 3 shows that the hot air “H” is blown onto the support surface  32  such that the support surface is also heated. The hot air is simultaneously reflected upward such that it is directed onto the connecting surface  25  from below. This causes the hot-melt adhesive to be very rapidly heated to the required melting temperature, and the fastener  3  can subsequently be lowered by means of the piston rods  11  and the receiver head  8  and pressed onto the support surface  32 , as shown in FIG. 4.  
         [0035]    [0035]FIGS. 6 and 7 show another fastener  34  that has a rectangular adhesion surface  35  that, for example, needs to be bonded to the edge of a kitchen sink basin  42 , specifically to its underside, that is partially indicated in FIGS.  9 - 12 . An elongated mounting part  36  is integrally formed in perpendicular fashion on the adhesion surface  35 , wherein said mounting part has a projecting catch tip  37  at its upper edge. A holding clamp, not shown, for mounting the sink  42  in a counter top can be fastened on and anchored to this catch tip.  
         [0036]    [0036]FIG. 8 indicates that this specially shaped fastener  34  can be manually placed and bonded onto a support surface with the same setting device as is the fastener according to FIG. 5. However, a different receiver part  38  needs to be inserted into the receiver head  8 , wherein the receiver part contains a corresponding oblong recess  39 , the geometry of which is suitably shaped to receive the mounting part  36 .  
         [0037]    [0037]FIGS. 9 and 10 show the receiver head  40  of another setting device that is arranged in a vertically movable fashion underneath the edge  41  of a sink  42 , and is especially designed for automatically setting the fasteners  34 . As with the previously described setting device, this receiver head  40  is surrounded by a closed wall  43  that is mounted on the head  44  of a hot-air blower  45  and extends up to the receiver head  40 .  
         [0038]    The enlarged detail of the setting device shown in FIG. 11 indicates that the upper rim  46  of the wall  43  that surrounds the receiver head  40  converges in the shape of a funnel until it reaches the outer contour of the receiver head  40 . As a result, the hot air H is focused and directed onto the adhesion surface  35  of the fastener  34  clamped in the receiver head  40  and onto the underside of the edge  41  of the sink  42 . The mounting part  36  of the fastener  34  is clamped in the oblong recess  47  of the receiver part  48  that, in turn, is securely embedded in the receiver head  40 .  
         [0039]    A pressing device  49  is stationarily arranged laterally above the receiver head  40 , wherein said pressing device essentially consists of a pivot drive  50  and a pneumatically actuated compressed air cylinder  51  with a vertically guided piston  52 . A horizontally projecting lever  53  (FIG. 10) is mounted on the piston end, wherein the free end of said lever is rigidly connected to a transversely extending beam  54  (FIG. 9). This beam  54  is connected to plungers  55  on both of its ends, wherein said plungers are swiveled by the pivot drive  50  from the waiting position shown in FIG. 9 over the edge  41  of the sink  42 , and are then lowered in the direction of the arrow “A” into the contact position on the edge  41  of the sink  42 , as is shown in FIGS. 10 and 12, by the compressed air cylinder  51 . The receiver head  40  is simultaneously pressed in the direction of the arrow “D” against the edge  41  from the bottom.  
         [0040]    Since the sink  42  normally needs to be equipped with several fasteners  34  along its edge  41 , the combination consisting of the receiver head  40  and the pressing device  49  may be placed into a suitable frame, not shown, at the predetermined locations of the sink edge  41  in order to simultaneously set the fasteners  34 . In this case, it is practical to arrange the hot-air blower  45  centrally underneath the blower heads  44  and to connect the hot-air blower to the blower heads by means of hoses.  
         [0041]    The automated setting and bonding of fasteners  3  onto support surfaces  32  is advantageously achieved by means of the following steps:  
         [0042]    inserting the fastener  3  by introducing the holding part  23  that projects from the adhesion surface  25  into the correspondingly shaped recess  16  of the receiver part  2 ,  
         [0043]    positioning the receiver head  8  at the predetermined location on the support surface  32  and lowering the receiver head  8 ,  
         [0044]    heating the support surface  32  while simultaneously reflecting the hot air back onto the adhesion surface  25 ,  
         [0045]    pressing the fastener  3  onto the support surface  32  and keeping the fastener there until a sufficient adhesive connection is produced, and  
         [0046]    removing the setting device from the support surface.  
         [0047]    When manually setting and bonding fasteners onto support surfaces by utilizing a setting device with three support rods  26 , the previously described process can be supplemented by the following steps:  
         [0048]    generating a negative pressure in the suction cups  27  while lowering the receiver head  8 , and  
         [0049]    venting the suction cups  27  before removing the setting device from the support surface  32 .  
                                       33   Vertical recess       34   Holding element       35   Connecting surface       36   Mounting part       37   Catch tip       38   Receiver part       39   Recess       40   Receiver head       41   Edge       42   Sinik       43   Surrounding wall       44   Head       45   Hot-air blower       46   Upper rim       47   Recess       48   Receiver part       49   Pressing device       50   Pivot drive       51   Compressed air cylinder       52   Piston       53   Lever       54   Beam       55   Plungers