Abstract:
A molding device moves at least one molding tool ( 10 ), especially for generating head geometries in plastic containers, by a link motion ( 22 ). The link motion brings the respective molding tool ( 10 ) into the closed position at least for closing the tool. This motion ( 22 ) is actuated by a drive ( 24 ), allowing for a novel drive and kinematic concept for the respective molding tool to completely avoid hydraulic drive means. The drive is preferably an electric drive, especially a step motor.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a molding device for forming heads of plastic containers. A molding tool is movable between a closing position closing a mold and an opening position opening a mold. A link motion control element is coupled to and moves the molding tool into the closing position. A drive is coupled to and actuates the link motion control element. 
   BACKGROUND OF THE INVENTION 
   Processes and devices for production of containers are known in the prior art (DE 199 26 329 A1). A hose of plasticized plastic material is extruded into a molding mechanism, with one end of the hose is closed by heat sealing. As a result of generation of a pneumatic pressure gradient acting on the hose, the hose is expanded and is applied to the shaping wall of the molding mechanism to form the container. The plastic container is then filled under sterile conditions by a charging mandrel inside the molding mechanism, and then hermetically sealed after removal of the charging mandrel to form a specified head geometry. Two head shaping jaws may be moved in the opposite direction by hydraulic drive means toward each other to obtain a closing position and away from each other into opening positions. The head geometries to be generated by the head jaws regularly also comprise the neck component of the plastic container, also in ampule form. The neck component is closed by a separation point, but may be opened for a fluid removal process as soon as the head piece is separated at the separation point by a toggle part molded on it and removed from the plastic container. 
   Such processes have been disclosed in a plurality of embodiments, and are widely used in packing systems for liquid or paste products, for example, in the disclosed “bottelpack7” system. 
   The hydraulic drive systems regularly employed in practical applications for the respective feed movement of the molding tool present problems in that any leakage may result in fouling with the fluid. The leakage results in problems, especially when the shaping machines are used for plastic containers in the pharmaceutical and food packaging fields and in medical technology in general. The maintenance cost is also increased. The hydraulic drive systems do not reach the desired or high cycle frequencies for mass production for the sake of precise positioning of the molding tools. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a molding device for moving at least one molding tool permitting application of modern drive concepts, such as electric or pneumatic drives. The maintenance cost of such drives is reduced, and permit especially high rates of output of goods to be produced, such as plastic containers, with high positioning accuracy for the molding tools. 
   This object is obtained according to the present invention by a molding device possessing a link motion control element for moving at least one molding tool, especially one for generation of head geometries in plastic containers. This element moves the respective molding tool to a closing position at least for closing the mold. The link motion control element is actuatable by a drive. On the basis of the link motion control element, a novel drive and movement concept is presented for the respective molding tool, one which makes it possible to dispense with hydraulic drive means entirely. Preferably, an electric or pneumatic drive is employed as the drive means. The link motion control element may, however, continue to be actuated by a hydraulic drive if the respective application appears to call for it and rigid requirements have not been set for sterile filling or clean room qualities. 
   The molding device of the present invention with the drivable link motion control element for a closing movement of the molding device permits uniform, safe, and position-accurate driving of the respective molding tool, and entails only a small maintenance expenditure. The link motion control element may be employed to execute a plurality of opening and closing processes in rapid sequence. This rapid sequence results in high output of goods to be produced, in particular those in the form of blow-molded plastic containers filled under sterile conditions. 
   In a preferred embodiment of the molding device of the present invention, the link motion control element has a slot guide in a feed component engaged by the actuating member. The actuating member may be moved into an opening position and a closing position of the molding tool by a rotation element actuated by the drive. Safe and precise positioning control is achieved as a result, along with clearly defined specific closing forces specified by the link motion control element. 
   In another especially preferred embodiment of the molding device according to the present invention, the feed element operates in conjunction with a rail-guided slide component which may be non-positively moved into the closing position of the molding device by the feed element. Preferably, the slide component may be moved together with the molding tool into the closing position of the latter, it being possible to reset the molding tool to its opening position by a reset means. A rigid machine configuration for the molding device is accomplished by the rail guide. Obstructions in operation are reliably excluded by the separate reset movement of molding tool and slide component. 
   In another preferred embodiment of the molding device according to the present invention, the closing force for the molding tool may be specified by a central adjusting means, preferably in the form of an energy accumulator. Pressure spring elements, such as disk springs or the like, are suitable for use as energy accumulators. The closing force of the link motion control element may be definitely limited by the adjusting means independently of the force applied. 
   In another especially preferred embodiment of the molding device according to the present invention, the molding tools opposite each other in pairs may be moved by a link motion control element synchronously into their closing position. Preferably, two link motion control elements of one slide component may be actuated by gearing actuated by the drive. In addition, preferably two slide components each with two link motion control elements may be moved in the opposite direction toward or away from each other by the rail guide. In this way a total of four molding tools with molding geometries mounted in sequence may be actuated to operate synchronously in pairs to generate several head geometries. 
   Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
       FIG. 1  is a top plan view of part of a molding device according to an embodiment of the present invention, with molding tool in closing position; 
       FIG. 2  is a top plan view of part of the molding device with molding tool in the opening position, the components of the molding device being juxtaposed along closing separation line I-I of  FIG. 1  to form the molding device as a whole; and 
       FIG. 3  is a side elevational view of the molding device in section taken along line II-II in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   First a part of the molding device for moving a molding tool  10  is to be described in detail with reference to the lower section of the illustration in  FIG. 1 . On its free front side, the molding tool  10  has trough-like recesses  12  forming mold halves for generation of head geometries for plastic containers (not shown). To generate the respective head geometries, the molding tool  10  operates in conjunction with a corresponding molding tool  10   a  with recesses  12 , as shown, by way of example, at the bottom of  FIG. 2  as viewed in the line of sight. The molding tool  10  is connected on its side opposite the recesses  12  to two adjusting components  14  the length of which may be adjusted by at least one stop component  16 , so that the adjusting components  14  provide a variable contact surface  18 . As a result, the molding tool  10  may be oriented on its free front side along a closing separation line I-I. In addition, the molding tool  10  may be reset independently, as is shown in  FIG. 2 , by reset means  20 , as, for example, means in the form of a conventional pneumatic cylinder, along a guide (not shown), from the closing position shown in  FIG. 1 . 
   In addition, the molding device has, for the purpose of moving the molding tool  10 , a link motion control element  22  by which the respective molding tool  10  may be actuated along the closing separation line I-I for the purpose of closing the mold. It is possible to actuate the link motion control element  22  by a drive  24 , preferably one in the form of an electric motor, e.g., an electric step motor, actuating gears. For this purpose, the link motion control element  22  has a slot guide  26  in a feed component  28 . This feed component  28  is integrated into a slide component  30 , and is movable together with it into the closing and opening directions of the molding tool  10  along two rail guides  32 . The slot guide  26  is mounted to move transversely to the rail guide  32  and to the direction of feed of the molding tool  10 . 
   The slot guide  26  is engaged by an actuating member  34  in the form of a cam roller  36  (see  FIG. 3 ). The function of pivoting of the actuating member  34  or cam roller  36  is performed by a rotation component  38  driven by a drive  24 . This rotation component  38  permits pivoting of the actuating member  34  in the direction indicated by the arrow  40 , as seen in  FIG. 1 , in order to move the feed component  28 , together with the slide component  30 , from its closed position shown in  FIG. 1  backward to an opening position as shown in  FIG. 2 . For the purpose of movement in the opposite direction into the closing position, the feed component  28 , together with the slide component  30 , is to be fed in the direction opposite that of the arrow  40  by an appropriate pivoting movement by the actuating member  34  (cam roller) in the direction of the closing separation line I-I. 
   The structure of the rotation component  38  is illustrated in greater detail in  FIG. 3 . First, the rotation component  38  is received so as to be stationary in a plate-shaped machine mounting support  42  which extends between the two rail guides  32 . A vertically oriented drive shaft  46  is rigidly connected to a toothed rim or gear  48 , is driven by this rim, and is mounted in this machine mounting support  42  so as to be rotatable by an appropriate roller bearing  44 . On the lower side of the drive shaft  46 , and accordingly below the roller bearing  44 , a lever piece  50  is rigidly connected to the drive shaft. The cam roller  36 , which can rotate freely in the lever piece  50 , extends through this lever piece  50  on its free left front side as viewed in the direction of  FIG. 3 . The slot guide  26  is mounted below the lever piece  50  in the feed component  28 , which in turn is an integral component of the slide component  30 . The teeth of the driving toothed rim or gear  52 , which may be driven by the electric drive  24 , in the form of a step motor, for example, mesh with the teeth of the toothed rim or gear  48 . The drive direction is indicated by an arrow  54 , the molding tool  10  being moved backward into its opening position in the respective direction. 
   On its free front side, the slide component  30  has carrier components  56  which carry the molding tool configured as a sort of movement slide as the molding tool moves into its closing position along the closing separation line I-I by the adjusting components  14  and into the closing position opposite the direction of movement of the opposite molding tool  10   a  if the latter moves into its closing position along the closing separation line I-I as shown in  FIG. 1 . In order to selectively adjust the closing forces, on the one free end of each rail guide  32 , central adjusting means in the form of a disk spring package  58  is mounted. Each spring package acts on the plate-like machine mounting support  42  mounted by end guides  60  so as to be movable longitudinally on the rail guides  32 . If the closing forces now become too high along the closing separation line I-I, the entire configuration of molding tool  10  with slide component  30  and machine mounting support  42  may be reset backward against the action of the disk spring package  58 . Consequently, safety is also provided if a machine collision unintentionally occurs, especially in the area of the molding tools  10 ,  10   a.    
   If, as illustrated in  FIG. 1 , driving toothed rim  52  with toothed rim or gear  48  is driven in the direction indicated by arrows  54  and  40  by drive  24 , the slide component  30  moves back to its initial position as shown in  FIG. 2 . The feed component  28  also moves into the position to the rear, with the cam roller  36  pivoting 180° backward from the position shown in  FIG. 1 . The carrier components  56  of the slide component  30  are accordingly moved away from the contact surface  18  by the adjusting components  14 . The respective molding tool  10 ,  10   a  is returned by the pneumatic cylinder  20  as reset means to the opening position, and is then available for another closing process. The pair of molding tools  10 ,  10   a  positioned opposite each other is actuated synchronously by the respective link motion control element  22  of the pair for a closing process for the purpose of executing a molding process. Consequently, the drives  24  for both molding tools  10 ,  10   a  are actuated synchronously in common by a central control unit (not shown). The respective synchronous actuation also facilitates ejection of the plastic container by its head component produced by the molding tools  10 ,  10   a . In view of the comparable structure of the two components illustrated in  FIGS. 1 and 2 , the reference numbers used in  FIG. 1  are used correspondingly in  FIG. 2 . In principle, however, the possibility also exists of using the link motion control element  22  to design only one molding tool  10  to be movable and thus of moving the molding tool  10  in relation to a stationary molding tool (not shown) for a molding process. In any event the molding device as described may be used to reach very high cycle frequencies, and thus, production speeds for plastic containers (not shown). In addition, precise positioning of the respective molding tool  10 ,  10   a  by the link motion control element  22  is also possible. 
   In order to achieve a still higher output rate at least one other molding tool  10  is provided which is mounted in tandem in a row and may be actuated by the central drive  24  as described by a corresponding link motion control element  22 . Consequently, the configuration as described shown in  FIG. 1 , above the drive  24  and the other toothed rim or gear  62  may be actuated along the arrow  64  if the slide component  30  is to be moved from its front position shown in  FIG. 1  to its rear position shown in  FIG. 2 . The slot guide  26  accordingly is also oriented in the same direction as described. Consequently, for a longitudinal operating process, the cam roller  36  rolls along a circular path around the drive shaft  46  and, in the process, carries feed components  28  and  30  along in longitudinal movement in parallel with the two rail guides  32 . The transverse position of the slot guide  26  as shown in  FIGS. 1 and 2  remains unchanged. Since maximum force restriction by the respective disk spring package  58  as adjusting means is effected on one side of the rail guide  32 , the respective configuration need not be provided in the case of the plate-shaped machine mounting support  42  shown in  FIG. 2 . 
   While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.