Abstract:
The invention relates to a blind rivet, a rivet pin, a holding device, a method for producing a blind rivet and a method for creating a riveted joint which enables a permanent joint to be produced between several workpieces in one working cycle.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention involves a blind rivet, a rivet mandrel, a mounting device, a process for manufacturing a blind rivet and a process for making a riveted joint. 
   2. Description of Related Art 
   A blind rivet (open-end blind rivet, closed-end blind rivet) is used to create an inseparable connection between several workpieces, whereby in order to set the rivet, only one side of the workpiece must be accessible. Usually, before the blind rivet is inserted, a hole must be pre-drilled. This practice, however, requires an additional work step and in addition, is time-consuming. 
   In order to minimize this time expense, an open-end blind rivet is provided with a tip that allows it to penetrate through the workpiece and anchor the blind rivet in a work operation using a device. It is disadvantageous in this process that only relatively thin-walled and soft plate materials can be penetrated. This is, on the one hand, based on the blind rivet manufacturing process, in which the tip of a blind rivet is usually created by massive forming (molding). This process, however, does not lead to sharp edges, but instead to rounded off edges of the tips, which thus only push through the workpieces, but can not cut through them. On the other hand, the material used, for example, is not able to handle the impact forces necessary for the penetration of harder and/or thicker materials. 
   SUMMARY OF THE INVENTION 
   The blind rivet according to the invention has the advantage that within one work step, a penetration through the workpieces and a subsequent anchoring of the blind rivet occurs. For this purpose, in the blind rivet according to the invention, the rivet shaft is constructed in a cup-shape (closed-end blind rivet) and the end of the rivet shaft away from the the rivet head-side is constructed as a tip and/or with a sharp edge. In this way, the penetration of the workpieces is made easier and also, it is possible to bore through harder and thicker materials. 
   According to an advantageous embodiment of the invention, the tip is ground to form a sharp edge. 
   According to another advantageous embodiment of the invention, the tip is cut to form a sharp edge. 
   According to another advantageous embodiment of the invention, the tip is cut to form a sharp edge and then ground after that. 
   According to another advantageous embodiment of the invention, the tip has an angle between 10° and 70°. 
   According to another advantageous embodiment of the invention, the tip has a cross-section that is at least triangular, a partition wall, a dagger shape, or the like. In this way, the cut edges end in one or more points on the outer end of the end of the mandrel. 
   According to another advantageous embodiment of the invention, the rivet head collar of the blind rivet has an undercut on the side that faces the workpiece. 
   According to another advantageous embodiment of the invention, the rivet head collar of the blind rivet is in the shape of a sphere. In the use of mounting devices in shooting devices or the like, the requirements of the mounting device and thus the material wear is reduced by these rounded-off areas. 
   According to another advantageous embodiment of the invention, the rivet head collar of the blind rivet is provided with a sealing element. In this way, the joint of the workpieces riveted with the blind rivet is impermeable to liquid and gas. 
   According to another advantageous embodiment of the invention, the degree of hardness of the rivet mandrel is at least 600 N/mm 2 . In this way, a deformation of the rivet mandrel by the impact is prevented. 
   The rivet mandrel of a blind rivet according to another embodiment of the invention has the advantage that, as in the key-lock principle, the free mandrel end ( 11 ) of the rivet mandrel ( 2 ) is shaped in a radially form-fit manner with the tool used to set the blind rivet (shooting device, blind rivet setting device, or the like). By the special design of the end of the mandrel, an interaction between the blind rivet and the special tool required to set the blind rivet is ensured. In this way, the insertion forces act in the direction and along the rivet mandrel axis. 
   According to an advantageous embodiment of the invention, the free mandrel end is constructed as a centrally symmetrical elevation or recess (cone, spherical segment, pyramid, spherical cap, indentation, or the like). In this way, a force acting on the mandrel end is at least partially guided further in the direction of the rivet mandrel center axis. 
   According to another advantageous embodiment of the invention, the rivet mandrel is tapered towards the mandrel end or constructed so that it expands. 
   The mounting device according to another embodiment of the invention, of a tool (shooting device, blind rivet setting device, or the like) for the fixing of a blind rivet, the advantage that the through-put opening of the mounting device has a ring, or the like, through the opening of which the blind rivet can be received. 
   According to an advantageous embodiment, the ring integrated in the mounting device is manufactured mostly out of rubber, or the like, and can thus be flexibly fit to different blind rivets, in order to prevent them from falling out, for example, from out of the shooting device. 
   The process according to the invention for manufacturing a blind rivet, provides for a sharpening of the rivet mandrel or the rivet shaft. This sharpening is done after or during the process steps customary in the course of machine manufacturing (e.g. cutting into lengths, pre-clenching, putting together of the individual parts) by cutting and/or grinding. 
   The process according to the invention for making a riveted joint, in particular using a device suitable for this purpose (shooting device, blind rivet setting device, or the like), provides that the forces of the tool (shooting device, blind rivet setting device, or the like) acting in the setting direction on the rivet mandrel, which cause the workpiece to be bored through until the stopper, are guided at least partially in the direction and along the rivet mandrel center axis. By this transfer of forces, even harder workpieces can also be bored through. 
   According to an advantageous embodiment of the process according to the invention, a pin transfers a force acting by an impact or striking on the rivet mandrel, which makes it possible to the go through workpiece. 
   According to a related embodiment of the process according to the invention, the pin is tapered on the side that faces the rivet mandrel, provided with an indentation (spherical cap) and/or another construction functioning for the purpose of centering. 
   According to another advantageous embodiment of the process according to the invention, the device (shooting device, blind rivet setting device) for fixing the rivet head has a mounting device with a ring made of rubber or the like. By fixed clamping of rivet head using the ring, a falling out of the blind rivet out of the device is prevented. 
   According to another advantageous embodiment of the process according to the invention, the boring of the workpiece is done as a cut. This cutting makes easier the penetration of the workpieces. 
   Additional advantages and advantageous embodiments of the invention can be ascertained from the following description, the drawing and the claims. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     Embodiment examples of the object of the invention are described in greater detail in the following. Shown are: 
       FIG. 1  a side view of a closed-end blind rivet with tip, 
       FIG. 2  a section view of the closed-end blind rivet with tip from  FIG. 1 , 
       FIG. 3  a three-dimensional view of the closed-end blind rivet with tip from  FIG. 1 , 
       FIG. 4  a side view of a closed-end blind rivet with tip and sealing ring, 
       FIG. 5  a section view of the closed-end blind rivet with tip and sealing ring from  FIG. 4 , 
       FIG. 6  a three-dimensional view of the closed-end blind rivet with tip and sealing ring from  FIG. 4 , 
       FIG. 7  a side view of an open-end blind rivet with sharpened rivet mandrel, 
       FIG. 8  a section view of the open-end blind rivet with sharpened rivet mandrel from  FIG. 7 , 
       FIG. 9  a side view of an open-end blind rivet with sharpened rivet mandrel and with an indented mandrel end and, 
       FIG. 10  a section view of an open-end blind rivet, which is fixed in a mounting device of a shooting device (not shown). 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The blind rivet shown in  FIG. 1  is a closed-end blind rivet and essentially consists of a rivet mandrel  2  and a closed-end rivet shaft  5 . The rivet shaft  5  is subdivided into the rivet head  6  and a closing head  8 . The end of the rivet shaft  5  away from the rivet head is shaped into a tip  9 . This tip makes it possible for the workpieces to be penetrated without the necessity for a pre-drilling. By a subsequent pull of the rivet mandrel  2  in the direction opposite the impact direction, the rivet shaft  5  and the closing head  8  become deformed resulting in a joining of the workpieces. 
   This deformation is brought about in a closed-end blind rivet through the rod head  3  shown in  FIG. 2 , which is pulled in the direction of the rivet head  6  in order to anchor the closed-end blind rivet. The riveted joint is thus made on the one side of the workpieces to be joined by the deformation of the rivet shaft  5  and the closing head  8  and on the other side of the workpieces by the rivet head  6 , whose edge has a rivet head collar  4 . After the joint has been made, the target breaking point  1  makes possible a separation of the rivet mandrel  2 . 
   In  FIG. 3 , a three-dimensional diagram of the closed-end blind rivet is shown. In this diagram, the free end of the rivet mandrel  2  is depicted clearly as a mushroom head. Depending on the special tool used (shooting device, blind rivet setting device, or the like), however, in order to achieve an optimal form-fit, other shapes (pyramid, cone, indentation, or the like) of the mandrel end  11  are possible. 
   The embodiment example of a closed-end blind rivet shown in  FIGS. 4 ,  5  and  6  is distinguished from the embodiment example shown in  FIGS. 1 ,  2  and  3  by the sealing element  7 , which after the connection, lies flush between the workpiece and the rivet head  6  and thus causes a liquid and gas impermeable seal. 
   The blind rivet shown in  FIG. 7  is an open-end blind rivet and consists essentially of a rivet mandrel  2  and a rivet tube. In this case, the rivet mandrel  2  is shaped into a tip  9 . This tip  9  makes possible the penetration of the workpieces without a pre-drilling being necessary. By a subsequent pull of the rivet mandrel  2  in the direction opposite the impact direction, the rivet shaft  5  and the closing head  8  are deformed resulting in a riveted joint of the workpieces. The mandrel end  11  has a rounded-off shape. However, in order to obtain an optimal fit to the tool used for processing (shooting device, blind rivet setting device, or the like), other shapes (pyramid, cone, indentation, or the like) of the end of the mandrel  11  are possible. 
   The undercut  12  shown in  FIG. 8  functions for the better support of the processed blind rivet on the workpiece. This undercut is also conceivable on closed-end blind rivets. 
   The mandrel end  11  shown in  FIG. 9  is indented in the shape of a spherical cap. However, other indentations  13  of the mandrel end  11  are also possible. By this design, the force of the pin is centered and guided into the rivet mandrel interior when the pin hits or strikes the end of the mandrel  11 . 
     FIG. 10  shows a section view of an open-end blind rivet, which is fixed in a mounting device of a shooting device (not shown). The spherical, rounded-off shape of the rivet head collar  4 , which makes it possible for the opening of the flexible ring  14  preferably made out of rubber to fit, in order to become clamped fixed behind so that the blind rivet is secured against falling out, is advantageous. By the rounded-off shape of the rivet head collar  4 , the wear on the ring  14  is minimized. The spherical, rounded-off shape of the rivet head collar  4  is also conceivable on a closed-end blind rivet. In order to fix the blind rivet in the mounting device, other embodiments are also conceivable, in addition to the ring  14  that forms the opening, possibly even several structural parts. 
   All of the characteristics depicted in the description, the following claims, and the drawings can be essential to the invention both individually as well as in any desired combination with each other. 
   REFERENCE NUMBER LIST 
   
       
         1  Target breaking point 
         2  Rivet mandrel 
         3  Rod head 
         4  Rivet head collar 
         5  Rivet shaft 
         6  Rivet head 
         7  Sealing element 
         8  Closing head 
         9  Tip 
         11  Mandrel end 
         12  Undercut 
         13  Indentation 
         14  Ring 
         15  Part of the shooting device