Abstract:
The invention relates to a method and a device for producing a structure made up of at least two bodies in a cavity of a mold defining the structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/DE2008/000158, filed Jan. 30, 2008, which designated the United States, and claims the benefit under 35 USC §119(a)-(d) of German Application Nos. 10 2007 006 102.3 filed Feb. 2, 2007 and 10 2007 016 188.5 filed Apr. 2, 2007, the entireties of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method for producing a structure made up of individual components and to a device for producing such a structure. 
     BACKGROUND OF THE INVENTION 
     A method for producing a structure made up of individual components is known from DE 10 2004 046 648 B4, the structure consisting of at least two bodies or components, mutually contacting surface regions of the bodies being adapted to one another in their design, each body being produced in an elastic balloon and the elastic balloons being arranged during the production of the bodies in a cavity of a mold defining the structure. 
     A device for introducing articles into an air balloon is known from DE 39 42 485 A1. This device for producing a structure comprises a mold having a cavity and at least one aperture leading through a wall of the mold. 
     SUMMARY OF THE INVENTION 
     The invention is based on the object of developing a method and a device which allows more individual influencing of the individual bodies and promotes more economical production of structures made up of bodies. 
     In the method according to the invention for producing a structure, the necks of at least some of the balloons are guided out of the cavity of the mold through apertures in a wall of the mold and these balloons are subsequently filled from outside the mold with a hardenable medium through their necks. As a result of this sequence of the method steps, it is possible to individually fill the individual balloons and to correctively intervene in the mold forming process. The core of the invention is thus a method which does not leave the shaping of the bodies or components or building blocks produced in the individual balloons exclusively to chance, but allows the individual bodies to be acted on and even permits corrections to the volume and/or the shape of the individual bodies. 
     The invention also makes provision to close the necks or trunks of the balloons after filling. This allows the mold to be individually rotated for the filling of further balloons without the risk of one of the balloons leaking. 
     Furthermore, the invention makes provision to withdraw the balloons from the bodies after hardening of said bodies. This produces neckless bodies. 
     According to the invention, provision is made to fill the balloons at pressure. This allows dynamic expanding of the balloons to be obtained using simple means, which expanding takes place as a function of the filling amount, but substantially independently of the position of the balloon. 
     The invention makes provision for an excess pressure of about 0.2 bar to 0.6 bar for the filling of the balloons. An excess pressure of this degree allows slow yet steady filling affording optimum control of the filling process. 
     Alternatively, the invention makes provision to generate a vacuum in the cavity of the mold. This causes the balloons to unfold prior to filling. Thus, a first defining of the proportions of the individual bodies is possible even before the filling process, wherein further unfolding or expanding of individual balloons can be temporarily or permanently prevented by closing the respective neck. 
     The invention makes provision to generate a vacuum in the cavity of the mold at a pressure which is reduced, relative to an ambient pressure, to at least 200 mbar, for unfolding the balloons. This allows optimum control of the expanding process of the balloons. 
     The invention makes provision to close the mold prior to filling of the balloons. This reliably prevents uncontrolled expanding of a balloon. 
     In particular, the invention makes provision to introduce the balloons prior to filling through the apertures of the mold. This allows contamination of the cavity or interior of the mold to be effectively prevented, as the cavity remains substantially closed during fastening of the balloons. 
     Furthermore, the invention makes provision to position at least one article in the mold prior to filling of the bodies, the article being at least partially embedded by the bodies, during filling of the bodies, as a function of its position in the cavity of the mold. This allows individual packaging of one or more articles, as a result of which articles can be surrounded in an almost form-fitting manner. Packaging of this type, made up of a plurality of bodies, can easily be detached from the packaged article or articles. 
     In the device according to the invention, at least two apertures are provided in the wall of the mold for feeding through in each case a neck of a balloon. This allows the production, in an influenceable manner, of a structure which consists of at least two bodies and in which the bodies influence one another in their shape during the production process and in this case adapt to one another in their shape. The core of the invention is thus a device allowing greater control over a production process in which the bodies of a future structure influence one another in their individual shape or their individual dimensions and their individual volume. 
     According to the invention, at least one inner wall of the mold is intended to promote sliding of an outer skin of the balloons. This allows steady unfolding of the balloons to be attained when said balloons are forced to unfold as a result of differences in pressure between the interior of the mold and the interior of the individual balloons. 
     The invention makes provision, in particular, to coat the inner wall of the mold with a liquid or viscous lubricant. An agent of this type is available, for example as soap suds, in an economical and environmentally acceptable form. 
     Additionally or alternatively, provision is according to the invention made to coat the inner wall of the mold with a solid material having a low coefficient of friction compared to the outer skin of balloons. This allows malfunctions to be effectively avoided when no lubricant is provided. 
     The invention makes provision to generate a vacuum in the interior of the mold. This allows unfolding of the balloons to be caused without said balloons having to be already filled. 
     Furthermore, the invention makes provision to associate a valve, which can be used to close the balloon which is guided through the respective aperture, with each of the apertures in the wall of the mold. This allows the expanding process of the individual balloons to be individually controlled. 
     The invention also makes provision to form the valve by a sleeve, which is rotatably mounted in the wall of the mold, and the neck of a balloon clamped in said sleeve. A valve of this type is easy to handle, as the individual balloon can be closed and opened by way of common rotation of the sleeve with the neck. 
     Furthermore, the invention makes provision to equip the device with at least one holding means which can be used to fix at least one article in the cavity of the mold, in particular without contacting the wall of the mold. As a result, the bodies, which can be filled after the fixing of the article, can be used to produce packaging or sheathing for the article with a precise fit, wherein the position of the article in the structure formed from the body can be determined in advance. 
     The invention makes provision to form the holding means by a thread, the thread being fastened to the wall and to the article. Threads require little volume of the cavity of the mold and thus impair the formation of the bodies only minimally during filling. 
     Finally, the invention makes provision to use one or more elastically extensible threads for fastening the article or articles in the mold. In the case of elastic threads, the bodies are restricted to a particularly low degree during the filling process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details of the invention are illustrated in the drawings based on schematically illustrated exemplary embodiments, in which: 
         FIG. 1  is a perspective view of a device according to the invention; 
         FIG. 2  is a perspective view of a sleeve pertaining to the device shown in  FIG. 1 ; 
         FIG. 3  shows a structure produced using the device shown in  FIG. 1 ; 
         FIGS. 4-9  are schematic sectional views of the device shown in  FIG. 1  at different moments of the production process; 
         FIG. 10  shows the sleeve which is shown in  FIG. 2  and has a balloon fastened therein; 
         FIG. 11  is a detailed view of  FIG. 10 ; 
         FIG. 12  shows the arrangement shown in  FIG. 10 , the balloon being expanded; 
         FIG. 13  shows the arrangement shown in  FIG. 12 , the balloon being closed; 
         FIGS. 14-18  are schematic views of a second device at different moments of the production process; 
         FIG. 19  shows a structure produced using the second device; and 
         FIGS. 20 ,  21  show a device in which an article is suspended in the mold. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of a device  1  according to the invention. The device  1  comprises substantially a mold  2 . The mold  2  has a large number of apertures  3  leading into a cavity  4  or interior  4  of the mold  2 . The mold  2  is designed as a hollow cube  5  having a wall  6 . The apertures  3  are designed as through-holes  7  and provided each to receive a sleeve  8 . Furthermore, a suction pipe  9  leads into the cavity  4  of the mold  2 . 
       FIG. 2  is an enlarged view of the sleeve  8  shown in  FIG. 1 . The sleeve  8  has a collar  9  which is formed by a peripheral groove  10 . Furthermore, the sleeve  8  has a shoulder  11  at which the sleeve  8  tapers from an external diameter D 8  to a smaller external diameter d 8 . The shoulder  11  prevents the sleeve  8  from slipping through the aperture  3  in the wall  6  of the mold  3  into the cavity  4  thereof (see also  FIG. 1 ). 
       FIG. 3  shows a structure  12  which was produced in the mold shown in  FIG. 1 . The structure  12  consists of a large number of individual bodies K, wherein five bodies K 1  to K 5  may be seen in  FIG. 3 . The individual bodies K and K 1  to K 5  respectively are adapted to one another in surface regions  13  where they rest flat against one another. For example, the body K 2  is adapted in its surface region K 213  to the surface region K 113  of the body K 1 . Pairs of magnets MP 1  to MP 3 , which are each composed of two magnets  32  and  33  positioned in adjacent and mutually abutting bodies K 2 , K 3  and K 4  respectively, are arranged in the bodies K 2 , K 3  and K 4 . 
       FIGS. 4 to 9  are schematic sectional views through the device  1  shown in  FIG. 1  in different, successive stages of the production process. In contrast to  FIG. 1 , in the illustration of  FIG. 4 , all the apertures  3  of the device  1  and of the mold  2  respectively are fitted with sleeves  8 . In the sectional views of  FIGS. 4 to 9 , an elastic ring seal  14  may in each case also be seen in each aperture  3 . These elastic ring seals  14  hold the sleeves  18  in the apertures  3  in a clamping manner. Furthermore, the elastic ring seals  14  cause sealing of the interior  4  of the mold  2  from an environment  15 .  FIG. 4  also shows how the suction pipe  9  penetrates the wall  6  and establishes a connection between the interior  4  and the environment  15 . The sleeves  8  are fitted with balloons B and B 1  to B 5  respectively. The respective necks  16  of the balloons B are guided through the sleeves  8 , a ring  18 , which is located at an opening  17  of the balloon B, being drawn in each case over the collar  9  of the sleeve  8  and lying in the groove  10  of the sleeve  8 . At the moment of the production process that is shown in  FIG. 4 , the bags  19  of the balloons B still sag into the interior  4  of the mold  2 . After the hanging of the balloons B into the sleeves  8  and the insertion of the sleeves  8 , which are fitted with the balloons B, into the apertures  3  of the mold  2 , the cavity  4  of the mold  2  is evacuated through the suction pipe  9 . This method step is illustrated in  FIG. 5 . A pump  20  is connected to the suction pipe  9  for suction-extracting the air from the cavity  4 . The apertures  3  are sealed by the sleeves  8  and the balloons B respectively against a subsequent flow of air out of the environment  15  into the cavity  4  of the mold  2 . As a consequence of a decreasing pressure p in the cavity  4 , the bags  19  of the balloons B 1 , B 2  and B 5  expand, air from the environment  15  subsequently flowing through the necks  16  of said balloons into interiors  21  of the balloons B 1 , B 2  and B 5  and the volumes V 1 , V 2  and V 5  of the balloons B 1 , B 2  and B 5  increasing in size. The volumes V 3  and V 4  of the interiors  21  of the balloons B 3  and B 4  do not increase under the conditions shown in  FIG. 5 , as the openings  17  of the balloons B 3  and B 4  are closed by a rubber plate  22  on which the device  1  rests. Once the balloons B 1 , B 2  and B 3  have expanded to a desired size or the desired volumes V 1 , V 2  and V 5 , said balloons are closed to prevent air from flowing out of or into their interiors  21 . The closing is carried out—as shown in FIG.  6 —by common rotating of the respective neck  16  with the respective sleeve  8  relative to the expanded bag  19  of the balloon B 1  or B 2  or B 5  which is supported, counter to the rotational movement, on an inner wall  24  of the mold  2 . After closing of the balloons B 1 , B 2  and B 5 , the device  1  is rotated through 180 degrees into the position shown in  FIG. 6 . Now, the balloons B 3  and B 4  are no longer closed by the rubber plate  22  and can expand, as the vacuum increases, into the interior  4  of the mold  2 , as the balloons B 1 , B 2  and B 5  did previously. In order to ensure steady expanding of the balloons B, provision is made to spray outer skins  23  of the balloons B and the inner wall  24  of the mold  2  with soap suds prior to the beginning of the evacuation process. 
     When the cavity  4  is almost completely evacuated, the balloons B have expanded, for example as shown in  FIG. 7 . The expansion behavior of the balloons B is dependent on a large number of factors. One important factor is, for example, the wall thickness or the material of the balloons B. Also decisive is, of course, the moment at which the balloon is closed or at which the balloon can start to expand. As soon as the balloons B have filled out the cavity  4  of the mold  2 —such as is shown in FIG.  7 —the filling of the balloons B can commence (see  FIG. 8 ). The pump  20  is active also during the filling process in order to keep the balloons B in the desired shape or at the desired volume. The balloons B are filled with a medium  25  which can harden, for example as a result of the action of heat, via a pipe  26  which is guided through the neck  16  of the balloon B 4  in the interior  21  thereof. The dimensions of the pipe  26  are such that the neck  16  of the balloon B 4  does not rest tight against the pipe  26 , so that the air which is displaced by the hardenable material  25  can flow out into the environment  15  through a gap  27  positioned between the neck  16  and the pipe  26 . The process of filling the balloon B 4  is concluded at the moment of the method shown in  FIG. 9 . After complete filling, the balloon B 4  was closed in the known manner by common rotation of its neck  16  with the sleeve  8 . At the moment of the method shown in  FIG. 9 , the balloon B 3  is now filled in a comparable manner through the pipe  26 . Once all the balloons B are filled and the hardenable material  25  has hardened in all the balloons B, the solid bodies K, which have already been shown in  FIG. 3 , have been produced in all the balloons B. Once the balloons B have been taken out of the mold and the balloons B have been withdrawn from the solid bodies K, there is then a structure  12  such as is shown in  FIG. 3 . 
       FIG. 10  shows the sleeve  8  which is shown in  FIG. 2  and has a balloon B clamped into the sleeve. The balloon B consists substantially of a bag  19  which merges with a neck  16 , the neck  16  forming an opening  17  with a ring  18 . In order to hold the balloon B on the sleeve  8 , the neck  16  of said balloon is drawn over the collar  9  of the sleeve  8 , the ring  18  snapping into the groove  10  of the sleeve  8 .  FIG. 11  is an enlarged view of a detail of  FIG. 10 . The enlarged view clearly shows how the balloon B is braced to the sleeve  8  by means of the ring  18  of said balloon. This prevents the balloon B and the sleeve  8  from rotating relative to each other about a center axis M. Frictional engagement between the balloon B and the sleeve  8  is important in order to be able to rotate and thus close the expanded balloon B, which is shown in  FIG. 12 , relative to the expanded bag  19  by common rotation of the sleeve  8  and the neck  16  about the center axis M, as is shown in  FIG. 13 . The sleeve  8  and the neck  16  jointly form a simple valve VT which can be repeatedly closed and opened. 
     A method for producing a structure according to the invention, in which an interior of a mold is evacuated to cause unfolding of balloons, includes for example the following preparations and steps: 
     Producing an airtight, dismountable mold or negative mold with apertures or holes for introducing sleeves or rotary nozzles and a suction pipe. 
     Preparing the mold by spraying the inner wall of the mold with a lubricant consisting, for example, of a mixture of water and flushing agent. This allows the balloons to slide steadily along one another and along the negative mold during expanding. 
     Introducing the balloons into the negative mold through the rotary nozzles and, in particular, subsequent outward reversing of the balloon lips or necks of the balloons over the rotary nozzle. In order further to improve the sliding of the balloons, provision is made to spray said balloon with the lubricant even before insertion. 
     The negative mold, which is fitted with rotary nozzles and balloons, is now placed onto a rubber mat. The balloons, which are fastened to the rotary nozzle resting on the rubber mat, are sealed by the rubber mat and cannot expand. Alternatively, some of the balloons which have not yet been expanded can also be closed by stoppers which are pressed into the sleeves. 
     A pump or vacuum pump draws the air out of the interior of the negative mold through the suction pipe. 
     The balloons, which are open to the environment, expand under the action of the reduced pressure which increases relative to an ambient pressure. 
     The expanded balloons are closed by rotating the rotary nozzles. 
     The negative mold is turned or the stoppers are removed from the sleeves and the process is repeated until all the balloons rest against one another and against the negative mold or until the balloons fill out the negative mold. 
     Each balloon can be vented as desired by deactivating the vacuum and/or briefly opening the balloons, by turning back the rotary nozzles. Other balloons can now expand as a result of the renewed switching-on of the vacuum pump and the opening of the balloons, by turning back the rotary nozzles. This process is repeated until the total volume of the interior of the mold has been distributed over the individual balloons in the desired manner. 
     Subsequently, the upwardly pointing rotary nozzles are opened, while the pump continues to operate. The individual balloons are filled through their balloon necks with the desired material and closed, after filling, by renewed rotation of the rotary nozzle. This process is carried out in all the balloons. 
     Once all the balloons have been filled, the vacuum pump is switched off. The material can now harden in the balloons. 
     After the hardening of the filling material, the rotary nozzles are drawn out of the holes of the mold. In the process, the balloon neck, along with the rotary nozzle, is in each case separated from the balloon. The negative mold is opened and the balloons, with the bodies hardened therein, are removed. The balloons are then stripped from the individual bodies. 
       FIGS. 14 to 18  are schematic views of a second device  1  at different moments of the production process. The device  1  comprises substantially a mold  2  surrounding a cavity  4  on all sides. The cavity  4  is accessible via apertures  3 . The apertures are designed as through-holes  7 . Sleeves  8 , into which balloons B can be clamped, can be inserted into the apertures  3 . With regard to the fastening of the balloons B to the sleeves  8 , reference is made in particular to  FIGS. 10 and 11  and the associated description. Furthermore, the device comprises a valve  28  via which air can escape from the cavity  4  into an environment  15 . The sleeves  8  or balloons B of the device  1  are connected to a pump device  30  by means of hoses  29 , a pump P or P 1  to P 6  being associated with each hose  29  in order to pump a hardenable material  25  into the balloons B at predeterminable moments or for predeterminable periods at an individually controllable pressure or individually controllable volume flow.  FIG. 14  shows the completely prepared device  1  in which all the apertures  3  are fitted with sleeves  8  and balloons B and which is already connected to the pump device  30 .  FIG. 15  shows the device  1  with the pump device  30  operating. The hardenable material  25 , for example liquid paraffin, which hardens during cooling, is pumped into the balloons B via the hoses  29 . In this case, the balloons B expand and displace air out of the interior  4  of the mold  2  through the valve  28 .  FIG. 16  shows the device  1  further on in the course of the production process; the balloons B are now filled to the extent that the interior  4  of the mold is almost completely filled out by the balloons B or the hardenable material  25  conveyed into the balloons B.  FIG. 17  then shows, in accordance with the further progress of the production process, how the completely filled balloons B are closed in the region of their necks  19  by automatically actuatable shut-off slides  31 . Subsequently, the hoses  29  of the pump device  30  can be separated from the device  1 , as leaking of the balloons B is effectively prevented by the shut-off slides  31  (see  FIG. 18 ). The balloons B and bodies K and K 1  to K 6  respectively, which are produced in the balloons B from the medium  25 , remain in the mold  2  until the medium  25  has completely hardened. 
       FIG. 19  shows a structure  12  which is produced using the second device  1  and is present after the hardening of the medium  25 , the subsequent removal from the mold and the withdrawal of the balloons. The structure  12  can now be broken down into the individual solid bodies K and K 1  to K 6  respectively and be reassembled therefrom. A broad range of structures  12  may thus be produced, using the same device, as a function of the parameters prevailing during filling of the balloons. 
     A method for producing a structure according to the invention, in which a hardenable material is pressed into the balloons in order to cause unfolding of balloons, includes, for example, the following preparations and steps: 
     Producing a tight mold or negative mold with sleeves and rotary nozzles for the inserting and closing of balloons. 
     Introducing the balloons into the interior of the mold from the outside through the rotary nozzles. 
     Fastening the balloons to the rotary nozzle, in particular by placing the respective balloon neck over the rotary nozzle. 
     Pressing the desired, hardenable material into the balloons until the balloons fill the interior and rest against the inner walls of the negative mold. 
     Closing the filled balloons by rotating the respective rotary nozzle with the balloon neck. 
     After the hardening of the filling material to form solid bodies, the rotary nozzles are drawn out of the holes of the negative mold and in this case the balloon neck is separated, along with the rotary nozzle, from the respective balloon. The negative mold is opened and the balloons, with the bodies contained therein, are removed from the mold. The balloons are stripped from the individual bodies. 
       FIG. 20  is a perspective view of a device  1 . The device  1  comprises a mold  2  having a cavity  4 . In order to simplify the illustration, the wall  6  of the mold  12  is shown transparent. Furthermore, in order to simplify the illustration, through-holes, through which the necks of balloons are guided, have not been shown. An article G is suspended in the cavity  4  via fastening means  34 ; the article G does not touch the wall  6  of the mold  2 . The article G is therefore held by the fastening means  34 , which are embodied as threads  35 , so as to hover freely in the cavity  4 . Once the article G has been suspended in the cavity  4 , balloons (not shown) are introduced through the through-holes (not shown) in the wall  6  and filled. The balloons being filled are then placed between the wall  6  of the mold  2  and the article G and embed said article.  FIG. 21  is a schematic view showing how the article G is embedded by three bodies K and K 1  to K 3  respectively illustrated by way of example, the bodies K and K 1  to K 3  respectively still being in their balloons B, B 1  to B 3 . The article G can be embodied, for example, as soap or as a sensitive optical component or as a liquid container or as a food product. Furthermore, provision is made to embed a metallic article and to fit the bodies, during the production process or after the production process, with magnets on their surfaces of contact with the article. This allows cohesion to be attained between the article and the bodies surrounding said article. According to a variant embodiment, provision is also made to make the article magnetic and to make the bodies magnetic and/or metallic on their contact surfaces. 
     The invention is not limited to the illustrated or described exemplary embodiments. On the contrary, it embraces developments of the invention within the scope of the claims. In particular, the invention also makes provision for the wall of the mold to be made with windows or from a transparent material such as, for example, acrylic glass. This allows the expansion process of the balloons to be observed, so that it is possible to intervene in a regulatory manner in the event of undesirable expansion behavior of one or more balloons. Furthermore, provision is made to embed components, such as for example magnets, into the balloons. This allows cohesion of a structure to be reliably ensured in different positions. Furthermore, pairs of magnets, which are distributed over two adjacent bodies, can facilitate assembly of the structure when the magnets of the pair of magnets attract each other when the bodies are positioned correctly. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Device 
           2  Mold 
           3  Aperture 
           4  Cavity, interior 
           5  Cube 
           6  Wall 
           7  Through-hole 
           8  Sleeve 
           9  Collar of  8   
           10  Groove on  8   
           11  Shoulder on  8   
           12  Structure 
           13  Surface region of K or K 1  to K 5   
           14  Elastic ring seal on  2   
           15  Environment 
           16  Neck of B or B 1  to B 5   
           17  Opening of B 
           18  Ring of B 
           19  Bag of B 
           20  Pump 
           21  Interior of B 
           22  Rubber plate 
           23  Outer skin of B 
           24  Inner wall of  2   
           25  Hardenable medium 
           26  Pipe 
           27  Gap between  16  and  26   
           28  Valve on  2   
           29  Hose from  8  to  30   
           30  Pump device 
           31  Shut-off slide in  2   
           32  Magnet 
           33  Magnet 
           34  Fastening means 
           25  Thread 
         B, B 1 -B 6  Balloon 
         d 8 , D 8  Diameter of  8   
         G Article 
         K, K 1 -K 6  Body 
         K 113  Surface region of K 3   
         K 213  Surface region of K 2   
         M Center axis of  8  or  16   
         MP 1 -MP 3  Pair of magnets 
         P Pressure in  4   
         P Pump 
         P 1 -P 6  Pump 
         V 1 -V 5  Volume of B 
         VT Valve made up of  8  and  16