Patent Publication Number: US-6905047-B2

Title: Apparatus and method for charging a riveting module with break-mandrel blind rivets or hollow-core rivets

Description:
RELATED/PRIORITY APPLICATIONS 
   This application claims priority with respect to International Application No. PCT/DE01/02932, filed Aug. 2, 2001, and German Application No. 20013365.9, filed Aug. 3, 2000. 

   The present invention relates to an apparatus and a method for charging a riveting module with break-mandrel blind rivets or hollow-core rivets consisting of a shell and a reusable mandrel being vertically movable between a lower placing position and an upper charging position. 
   The feeding of break-mandrel blind rivets or hollow-core rivets and especially the charging of a riveting module with break-mandrel blind rivets or hollow-core rivets always still is problematical. The corresponding devices either are rather complex and, followingly, difficult to maintain and to produce, or are not working sufficiently reliable especially if with the rivets to be placed the mandrel in relation to the shell is bent or is inclined. 
   It is therefore the task to be solved by the present invention to improve such an apparatus for charging a riveting module with break-mandrel blind rivets or hollow-core rivets in such a way that the construction is drastically simplified and is usable in any deliberate position while simultaneously break-mandrel blind rivets or hollow-core rivets having less than a well centering of the mandrel can be placed without problem as well as to propose a suitable method for charging a riveting module with break-mandrel blind rivets or hollow-core rivets. 
   According to the invention, the above task in an apparatus for charging a riveting module with break-mandrel blind rivets of the defined species is solved by the features of claims  1 ,  2  or  3  as well as by the method according to claim  10 . 
   In the meantime, the inventors have found out, too, that the apparatus according to the invention and the method according to the invention excellently are suitable for placing so-called hollow-core rivets. Hollow-core rivets are rivets which in their appearance are similar to break-mandrel blind rivets. Contrary to the break-mandrel blind rivets, the corresponding mandrel is not broken-off with hollow-core rivets but instead is completely withdrawn. Due to this fact, the mandrel can be used again. Hollow-core rivets therefore are consisting of a shell and a re-usable mandrel. 
   The placing of hollow-core rivets generally is done such that these rivets are fed singularly, the re-usable mandrel is inserted into the shell and the combination of mandrel and shell thereafter is used as a usual break-mandrel blind rivet. Only when placing the only difference is apparent: The mandrel is not broken-off during the placing of the rivet but instead is completely withdrawn from the rivet. He thereafter can be used again. 
   The invention therefore specifies corresponding apparatuses for charging a riveting module with hollow-core rivets by the technical teaching of claims  13 ,  14  and  15  as well a corresponding method according to claim  22 . 
   In this connection, it is preferred to provide for a further pressurized air nozzle in the lateral direction of movement of the funnel next to the funnel ending above the funnel. Hereby after the placing of the rivet, the broken-off remainder of the mandrel remaining in the riveting module can be blown out of the riveting module. The apparatus therefore, even working perpendicularly downward, can be operated without a sucking-off of the mandrels. This leads to an enormous saving of air and therefore saving of costs. 
   In this connection, it is further preferred that the additional pressurized air nozzle is positioned at the side of the funnel which is facing the riveting module. In this way, the operational movements can be optimized further. 
   According to the invention, it is further especially preferred if the funnel is provided with a section which downwardly is cone-shaped. In this way, for changing to another type of rivet merely the rivet feeding tube has to be exchanged as far as the diameter of the riveting head is not changing. Additionally then the funnel has to be exchanged. 
   It is further preferred that the funnel above the cone-shaped section is having a slightly broader cylindrical section, wherein the transition between these two sections is formed by an annular horizontal surface the exterior diameter of which is slightly larger than the exterior diameter of the rivet. 
   Further, it is preferred that the rivet feed is formed as a long straight perpendicular tube. In this way, the feeding of the rivets is further accelerated. 
   Further, it is especially preferred that all driving means are performed as pneumatic cylinders. In this way, the costs for obtaining the parts and for the operation can be minimized further. 

   
     In the following, one exemplary embodiment of the present invention is more detailly described with reference to the enclosed drawings. In the drawings show: 
       FIG. 1  a cross-sectional view of the apparatus according to the invention in the starting position; 
       FIG. 2  the apparatus according to  FIG. 1  in the blow-off position for blowing out the mandrel; 
       FIG. 3  the apparatus according to  FIG. 1 , wherein the riveting module has been moved to the resting position; 
       FIG. 4  the apparatus according to  FIG. 1 , wherein the gripping device was closed; 
       FIG. 5  the preparation for transferring the rivet to the riveting module; 
       FIG. 6  the riveting module during the centering and receiving of the rivet with the subsequent opening of the gripping device; 
       FIG. 7  the blowing-in of the rivet into the riveting module with the subsequent generation of a riveting preparatory pressure in the riveting module itself. With this the clamping jaws in the riveting module (not shown) are closed with low hydraulic pressure and are holding the rivet in its position; 
       FIG. 8  the riveting module charged with the new rivet in the starting position; 
       FIG. 9  the return of the funnel in its starting position; 
       FIG. 10  the riveting module in the riveting position; 
       FIG. 11  the riveting module after placing the rivet; 
       FIG. 12  the blowing out of the further mandrel from the riveting module; 
       FIG. 13  a representation of a gripping device according to the invention for the mandrel of the blind rivet with a blind rivet from the side; 
       FIG. 14  the gripping device according to  FIG. 13  from above in the closed state; 
       FIG. 15  the gripping device of  FIG. 13  from above in the opened state. 
   

     FIG. 1  is showing an embodiment of an apparatus according to the invention in the starting position in cross-section. The apparatus according to the invention comprises a riveting module  10 , which is equipped with a riveting equipment  12  for placing break-mandrel blind rivets  100 . The riveting module  10  by means of a slide  14  is vertically reciprocable upwardly and downwardly on a base support  16 . The slide  14  is moved upwardly and downwardly by means of the pneumatic cylinders  18 ,  20 . Between the riveting module  10  and the most outward pneumatic cylinder  18 , there is positioned a stiff, straight long tube  22 , the interior diameter of which is slightly larger than the exterior diameter of the blind rivets  100 . This tube  22  serves as a rivet feed, the break-mandrel blind rivets are blown in by means of pressurized air with their head forward/downward via a usual rivet feed from a usual separating device into the feed tube  22 . 
   In the starting position shown in  FIG. 1  exactly below the feed tube  22  there is a funnel  24  consisting of a lower cone-shaped and downwardley tapering section  26  and a slightly broader cylindrical section  28  above said cone-shaped section  26 . The transition between these two sections  26 ,  28  is formed by an annular horizontal surface, the exterior diameter of which is slightly larger than the exterior diameter of the rivet. Correspondingly, the interior diameter of the cylindrical section  28 , too, is slightly larger than the exterior diameter of the rivet  100 . The funnel  24  is fixed by screws to a horizontally movable slide  30  having an integrated pneumatic cylinder. 
   On the bottom tip of the cone-shaped section  26  of the funnel  24  there is positioned a pressurized air nozzle  32 . Alternatively or additionally in the nosepiece of the riveting module  10 , too, there can be provided a suction or vacuum line. At the exterior end, i.e. the end of the slide facing the riveting module  10 , there is provided a further pressurized air-line  34  having a further pressurized air nozzle  36  positioned at the height of the upper end of the funnel  24 . 
   Between the feed tube  22  and the funnel  24  additionally there is provided a gripping device  38  mounted on the slide  30 , too. Said gripping device is consisting of a pneumatic angle gripper and two special centering gripping arms. The pneumatic stop cylinder  40  provides for an intermediate position of the slide  30 . The exact function of the gripping device  38  is more detailly discussed with reference to  FIGS. 13  to  15  showing the gripping device  38  in detail. The cylinder  40  is positioned on the slide  30 . 
   In the following, with reference to  FIGS. 1  to  12 , the working procedure of the apparatus according to the invention shown in  FIG. 1  is discussed in detail. 
   As already stated,  FIG. 1  is showing the starting position of the apparatus according to the invention when beginning the work. The first blind rivet  100  already has been deposited by the feed tube  22  and the opened gripping device  38  in the funnel  24  with its head facing forward, wherein the head of the blind rivet either is resting on the annular horizontal surface or in the cone-shaped section of the funnel  24 . The gripping device  38  is now closed. 
   As shown in  FIG. 2 , the stop cylinder  40  is moved upwardly and thereafter the slide  30  is moved to the exterior such that the further pressurized air nozzle  36  is moved under the nose-opening of the riveting equipment  12 . In this position, now pressurized air is blown through the pressurized air-line  34  and the pressurized air nozzle  36  into the riveting equipment to remove remainders of the mandrel of a previously placed rivet possibly still present. In this way, in each operational position, even in the vertically downward operational position shown, an expensive sucking of the mandrel is avoided. 
   As shown in  FIG. 3 , now the inner pneumatic cylinder  20  is actuated. Said cylinder thereby is moving himself and the outer pneumatic cylinder  18  connected therewith upwardly. Thereby the slide  14 , too, and the riveting module  10  connected therewith is raised. 
   As shown in  FIG. 4 , now the stop cylinder  40  is returned. 
   As shown in  FIG. 5 , now the slide  30  is moved outwardly until the mandrel  110  of the break-mandrel blind rivet  100  exactly is positioned below the opening of the nosepiece of the riveting equipment  12 . The nosepiece of the riveting equipment  12  now is opened. 
   As shown in  FIG. 6 , now the pneumatic cylinder  20  is retracted again. Thereby the slide  14  and followingly the riveting module  10  is moved downwardly such that now the mandrel  110  of the break-mandrel blind rivet  100  is exactly centered and received in the nosepiece of the riveting equipment  12 . The exact centering of the mandrel  110  with respect to the position of the opening of the nosepiece of the riveting equipment  12  in this connection is occurring by the gripping device  38  which is holding the mandrel  110  in an exactly defined position. Thereafter, however, the centering is ensured by the nosepiece of the riveting equipment  12  and therefore the gripping device  38  can be opened again. 
   As soon as the gripping device  38  is opened, pressurized air is blown through the pressurized air nozzle  32  into the funnel  24 . Thereby the break-mandrel blind rivet  100  is lifted and is completely blown into the rivet placing head  12  as this already is shown in FIG.  7 . In this way, it is not necessary anymore to lower the rivet placing head  12  until the rivet  100  is reaching the placing position in the rivet placing head  12 . Further, tolerances in positioning can be equalized. 
   As an alternative to the blowing-in of pressurized air through the pressurized air nozzle  32  in the nosepiece there can be provided a negative pressure or vacuum line which is operated as soon as the gripping device  38  is opened. The break-mandrel blind rivet  100  in this way is sucked into the nosepiece instead, as previously described, being blown-in. In this way, it can be ensured in a better way that the break-mandrel blind rivet is correctly entering the nosepiece. The further procedure again is the same irrespective whether pressurized or suction air is used. Besides that it is possible, too, to combine both methods such that simultaneously pressurized air is blown through the funnel and simultaneously it is sucked-off through the nosepiece. 
   Now the clamping jaws in the riveting equipment  12  are closing upon the mandrel  110  of the break-mandrel blind rivet  100 . The blind rivet  100  now is therefore in a suitable position for placing in the riveting equipment  12 . 
   As shown in  FIG. 8 , the riveting module  10  now has been raised to enable the slide  30  to return sidewardly and to move the riveting module  10  passing the slide  30  in the placing position. To this end, firstly, as shown in  FIG. 8 , the inner pneumatic cylinder  20  is again actuated such that the same is lifting the pneumatic cylinder  18  connected therewith and therefore the slide  14  and the riveting module  10  again. 
   Correspondingly,  FIG. 9  is showing the state in which the slide  30  had been returned again, the gripping device  38  still is opened. In this state already the next break-mandrel blind rivet  100  can be fed through the feed tube  22  and can be deposited in the funnel  24 . 
     FIG. 10  then shows the state in which the riveting module is in the placing position. In this state, the pneumatic cylinder  20  has been retracted and the pneumatic cylinder  18  has been fully extended. The slide  14  thereby is completely lowered. The break-mandrel blind rivet  100  now can be placed by the riveting module  10 . The gripping device  38  is closed. 
   After the placing, the riveting module  10  is returned again as this is shown in  FIG. 11  by retracting the pneumatic cylinder  18  again. As clearly can be seen from  FIG. 11 , the broken-off remainder of the mandrel  110  of the break-mandrel blind rivet  100  still is remaining in the riveting equipment  12 . As soon as the riveting module  10  therefore is in the position shown in  FIG. 11 , the slide  30  again can be moved outwardly so far until the nosepiece of the rivet placing head  12  exactly is positioned below the further pressurized air nozzle  36 . By means of the pressurized air-line  34  now pressurized air is fed to the pressurized air nozzle  36 . Simultaneously the nosepiece of the rivet placing head  12  is opened and by the air stream the rest of the mandrel  110  is blown out upwardly. For example, an exit hose can be connected to the top of the riveting module  10  by the means of which the remainder of the mandrel is guided to a suitable waste container. The state according to  FIG. 12  is corresponding to the state of FIG.  2  and therefore the operation procedure cyclically is continued again with FIG.  3 . 
   In the following, the gripping device  38  will be more detailly explained with reference to  FIGS. 13  to  15 . 
     FIG. 13  is showing the gripping device  38  from the side while holding the mandrel  110  of a break-mandrel blind rivet  100 . The gripping device comprises a split arm  42  into which a further arm  44  is engaging. 
   As clearly shown in  FIGS. 14 and 15 , the two arms  42 ,  44  each are pivotably mounted on a vertical axis. In the closed state, the two arms  42 ,  44  are interengaging such that the mandrel  110  firmly is gripped. As can be learnt from  FIG. 15 , the main problem of the construction of the gripping device  38  is residing in the fact that the gripping device  38  is not allowed to become too large in the opened state and that nevertheless the break-mandrel blind rivet  100  can pass between the two arms  42 ,  44 . In the closed state (FIG.  14 ), the gripping device  38  however has to hold the very thin mandrel  110  firmly. 
   To solve this problem, the two arms  42 ,  44  are designed as shown in FIG.  15 . They are having an enlarged gripping section in which each a slantly designed recess is provided and closing an right angle and being turned against the direction of the arms  42 ,  44  by 45°. In this way, both a firm gripping of the mandrel  110  as shown in  FIG. 14  can be achieved and an extensive opening, too, such that the entire break-mandrel blind rivet  100  can pass as shown in  FIG. 15  without that the device  38  in the opened state is needing unnecessary much room sidewardly.