Abstract:
A demolding device ( 10 ) for demolding a work piece from a mold comprises a hold-down element ( 18 ) that is disposed between the mold pieces in the closed state of the mold and extends up to or into a cavity provided for producing the work piece. A control sleeve ( 11 ) is connected to the hold-down element ( 18 ) and is coupled with one of the mold parts in a form-fitting manner via a guide device. The piston ( 11 ) is displaceable along a first path (w 1 ) along the stroke direction limited by the guide device and is mounted in the guide device in a pivotable fashion. Upon a pivot motion, the end of the piston ( 11 ) facing the cavity moves away from the cavity. A first control piece ( 16 ) is connected to the other mold piece, the control piece blocking a pivoting of the piston ( 11 ) and/or the hold-down element ( 18 ) during the first path (w 1 ).

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a demolding device for demolding a work piece from a mold that comprises an upper mold component and a lower mold component with the mold components being movable in relation to each other along a stroke direction. 
     In conventional molds, the work piece is lifted up together with the upper mold component and in this manner separated from the lower mold component. Additionally, to separate the work piece from the upper mold component, one or more pin-shaped ejectors are provided at the upper mold component forcing a relative movement between the work piece and the upper mold component and in this manner leading to the desired separation. A disadvantage of this method is that the application of force leads to undesired deformation of the still warm work pieces in the area of the ejector. This reduces the optical impression of the work pieces. 
     It is also known to provide at least one, preferably two hold-down elements on the side in the area of the separation surface between the upper mold component and the lower mold component, with said hold-down element separating the work piece from the upper mold component after a specified distance. To be able to remove the work pieces, the operating personnel must pivot the hold-down elements out of the work area by 90° to 180° and then later pivot them back in. If pivoting in is forgotten, the mold can be damaged or destroyed when it is closed. 
     SUMMARY OF THE INVENTION 
     It is the objective of the invention to provide a demolding device with a simple design for demolding a work piece from a mold. 
     This objective is achieved by a demolding device which comprises a hold-down element that is disposed between the mold pieces in the closed state of the mold and extends up to or into a cavity provided for producing the work piece. A control sleeve is connected to the hold-down element and is coupled with one of the mold parts in a form-fitting manner via a guide device. The piston is displaceable along a first path (w 1 ) along the stroke direction limited by the guide device and is mounted in the guide device in a pivotable fashion. Upon a pivot motion, the end of the piston facing the cavity moves away from the cavity. A first control piece is connected to the other mold piece, the control piece blocking a pivoting of the piston and/or the hold-down element ( 18 ) during the first path (w 1 ). 
     This objective is achieved by a demolding device with the features of claim  1 . 
     Preferably, the demolding device is placed in pairs at opposite sides of a mold that comprises an upper mold component and a lower mold component, whereby the mold components are movable in relation to each other along a stroke direction. 
     The designations “upper mold component” and “lower mold component” are used in a device in terms of the present invention only to address the one or the other half of the mold of a casting tool with reference to the drawings of the description of the present invention without specifying with it a mandatory spatial location. When the description below states, for example, that the piston is positioned at the lower mold component and the hold-down element at the upper mold component, a reverse arrangement is possible just as well. 
     The demolding device according to the invention comprises: 
     A hold-down element, which in the closed state of the mold is arranged at least partially between the mold components and extends into a cavity provided for manufacturing the work piece where it forms a portion of a shape-giving surface, 
     A piston that is connected to the hold-down element and that is coupled in a form-fitting manner via a guide device with one of the mold components, for example the lower mold component, and 
     A control component that is connected to the upper mold component, for example. 
     The function of the aforementioned tool is as follows: 
     The piston coupled with a mold component can be moved along the stroke direction along a first path distance w 1  that is restricted by a guide device. Thus, the hold-down element connected to it can remain in contact with the other mold half during the path distance w 1 . During the first path distance w 1 , pivoting of the piston and/or of the hold-down element is blocked. 
     At the end of the path distance w 1 , the piston and the hold-down element are held back in the stroke direction, while that half of the mold that was initially in contact with the hold-down element can continue to travel across a second path distance w 2 . In the area of the second path distance, the piston and the hold-down element remain stationary in relation to the lower mold component, while the upper mold component continues to move away from the lower mold component. In this manner, a work piece adhering to the upper mold component is held back by the hold-down element and is stripped off. 
     During the second path distance w 2 , the upper mold component can continue its movement in the stroke direction, whereby the control component connected to it continues to block a pivot motion of the hold-down element. 
     The blockage is lifted only after the additional path distance w 2 , at which point the hold-down element can be pivoted to the side, moving the end of the piston that previously covered the cavity in the mold in a pivoting motion outwards. This permits access to the work piece in the cavity through automatic grippers, or with a vertical orientation of the separating plane, the work piece can now drop out freely between the mold components that have been lifted off each other. 
     In the third path distance, the piston with the hold-down element can rotate around the rotational axis perpendicular to the stroke movement in particular with the aid of the spring element. 
     During closing, in reverse order first the piston with the hold-down element is returned to its starting position by the first control component against the force of the spring element and only then will the upper mold component be placed onto the lower mold component. 
     With this inventive solution, the work piece is fully separated from the lower mold component and the upper mold component when the mold is opened and at the same time the hold-down element is moved out of the way. This is done fully automatically. When the mold is closed, the hold-down elements are again fully automatically returned to the initial position such that damage is prevented reliably. In addition, this inventive solution has a simple design and can be adapted easily to all embodiments of molds. Finally, ejectors can be omitted entirely, leading to cost-savings. 
     The arrangement of a spring element or other actuator element used for bracing and located between the piston and the lower mold component near the hold-down element close to the end of the piston has the advantage that the lever for separating the hold-down element can be relatively large. 
     The use of a recess in the upper mold component for receiving the hold-down element prevents damage to the mold during closing. 
     The arrangement of a mold draft in the area of the hold-down element pointing toward the upper mold component ensures that said hold-down element does not become wedged together with the upper mold component when the mold is opened but instead that it separates easily from the recess. 
     The arrangement of a second control component in the area underneath the rotational axis of the lower mold component, which also causes a rotational movement of the piston around the rotational axis against the force of the spring element when closing the mold, improves the function of the mold and ensures that the hold-down element is pressed in reliably. Additional advantageous details of embodiments of the invention become apparent from the subordinate claims, the drawing and the associated description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a cross-section of an exemplary embodiment of a mold with a demolding device according to the invention. 
         FIG. 2  shows a simplified, perspective view of the exemplary embodiment according to  FIG. 1 . 
         FIG. 3  shows two perspective views of a demolding device according to the exemplary embodiment. 
         FIG. 4  shows a simplified, perspective view of a first control component according to the exemplary embodiment. 
         FIG. 5  shows a simplified, perspective view of a piston according to the exemplary embodiment. 
         FIG. 6  shows a simplified, perspective view of a hold-down element according to the exemplary embodiment. 
         FIG. 7  shows a simplified, perspective view of a second control component according to the exemplary embodiment. 
         FIG. 8  shows a simplified, perspective view from below of an upper mold component according to the exemplary embodiment. 
         FIGS. 9 to 12  each show a perspective view of a mold with a demolding device in various states of movement. 
         FIG. 13  shows a second, compact embodiment of a demolding device according to the invention. 
         FIGS. 14 to 16  show perspective views of various states of movement of the second embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention will now be described with reference to  FIGS. 1-16  of the drawings. Identical elements in the various figures are designated with the same reference numerals. 
     The mold designated in  FIG. 1  overall with the number  100  exhibits an upper mold component  20  and a lower mold component  30 , which together form a mold for producing a work piece  4 , in particular one made of plastics. In the shown exemplary embodiment, this is a tub-shaped work piece  4 . Here, the upper mold component  20  and the lower mold component  30  are each connected to two carriers  5  that are used to move the two components  20 ,  30  in a known manner relative to each other in a stroke direction  6 . 
     On opposite sides of the mold  100 , respective demolding devices  10  are provided for demolding the work piece  4  from the mold  100 . 
     With the essentially known production of a work piece through injection molding, the mold  100  is initially closed such that the upper and the lower mold components  20 ,  30  are contacting each other and a suitable material, for example polyurethane, is injected through the cavities formed by the recesses in the mold components  20 ,  30 . After at least partial curing, the mold  100  is opened and the work piece  4  is separated from both the lower mold component  30  and the upper mold component  20  and then removed. Typically, the mold  100  is designed such that the work piece  4  remains stuck to the upper mold component  20  when the mold  100  is opened and is separated from the lower mold component  30  when the mold components  20 ,  30  travel apart in the direction  6 . To this end, for example undercuts (not shown) can be provided at the upper mold component  20  that clamp the work pieces  4  initially to the upper mold component  20  and allow for it to be pulled out of the lower mold component  30 . 
     According to the invention, on opposite sides of the mold  100 , respective demolding devices  10  are provided for separating the work piece  4  from the upper mold component  20 . 
     According to this exemplary embodiment, the mold  100  is cuboidal and a demolding device  10  is arranged on each longitudinal side. The number of demolding devices  10  is also variable, with generally at least two demolding devices  10  being required for a reliable operation. 
     The arrangement of the demolding devices  10  is also not limited to the shown positions but can be selected according to the work piece  4  that is to be produced. 
     The core piece of the demolding device  10  according to the invention is a hold-down element  18 , which in the closed state is arranged between the mold components  20 ,  30 . A recess  21  is provided in at least one mold component  20  or  30  for fully receiving the hold-down element as shown in  FIG. 8 . The areas of the hold-down element  18  located between the mold components  20 , become with at least one surface a part of the shaping mold  100 . 
     The demolding device  10  exhibits at least 
     One guide component  12 , 
     One piston  11 , 
     One actuator element, in particular a spring element, not shown in any detail in the Figures, 
     the hold-down element  18 , and 
     A first control component  16 . 
     In the exemplary embodiment shown, the guide component  12  is connected to the lower mold component  30 ; however, a reverse arrangement is possible as well. 
     In this example, the piston  11  is connected to the hold-down element  18  in a detachable manner, which allows for easy adaptation of the hold-down element to the mold components  20 ,  30 . By changing the hold-down element  18 , the remaining demolding device  10  can be transferred to other molds  100  such that only partial areas of the hold-down element that engage in the cavity need to be adapted individually. 
     Alternatively, the piston  11  and the hold-down element  18  can also be made of one piece or can be assembled of more than two pieces. 
     The piston  11  and the guide component  12  act together in such a manner that the piston  11  can be moved by a first specified path distance along the stroke direction  6  in relation to the guide components  12  and at the same time can be pivoted around a rotational axis  13  that is perpendicular to the stroke direction  6 . 
     The movement is enabled in a simple manner in that the guide component  12  exhibits a guide, for example in the shape of a cuboidal recess for the piston  11 , which in the example has a cuboidal design. Of course, other cross-sectional shapes or other guide alternatives are possible as well. 
     In complementary fashion, the guide components  12  exhibit recesses  14  extending in the respective stroke direction  6 . The rotational axis  13  engages in these recesses  14 . In this manner, the rotational axis  13  supported by the piston  11  fulfills in the shown exemplary embodiment of the invention several functions at the same time: 
     First, it serves as a glide element in a guide track that is formed by the recesses  14  and guides the path of the piston  11 . 
     Then the rotational axis  13 , when it has arrived at the end of the recesses  14 , serves as a fixed stop and coupling element for holding back the piston with the hold-down element  18  at the lower mold component  30 . 
     And finally it serves the pivotability of the piston  11 . 
     In the first exemplary embodiment, the rotational movement of the piston  11  around the rotational axis  13  is caused by an actuator element (not shown), in particular a compression spring, which is preferably arranged adjacent to the hold-down element  18  between the piston  11  and the lower mold component  30 . Through this arrangement, the lever arm and thus the moment for the pivoting movement are increased. However, it is also possible to position the spring element at another location as long as this enables the same movement. 
     Aside from a conventional helical spring, it is also possible to employ other, for example, mechanical, pneumatic or hydraulic actuators as the actuator elements. 
     In the closed state of the mold  100 , the hold-down element  18  that is connected to the piston  11  extends in the area between the lower mold component  30  and the upper mold component  20  into the area of the work piece  4  that is to be produced. When opening the mold  100 , the hold-down element  18  separates the work piece  4  from the upper mold component  20 . In the fully opened state of the mold  100 , the hold-down element releases the work piece and allows for the removal of the work piece  4  from the mold  100 . 
     The first control component  16  is connected to the upper mold component  20  and exhibits a control edge  15  with two regions  15   a ,  15   b , whereby the one region  15   b  of the control edge that is pointing toward the lower mold component  30  causes a rotational movement of the piston  11  around the rotational axis  13  against the force of the spring element in the direction of the lower mold component  30  during closing and whereby the other region  15   b  of the control edge  15  that is pointing toward the upper mold component  20  enables a translatory movement of the first control component  16  relative to the piston  11  essentially along the stroke direction  6 . 
     To support the rotational movement of the piston  11  back into the starting position, an additional control component  19  can be arranged at the lower mold component  30  as shown in the exemplary embodiment and act with its incline  19 . 1  together with the corresponding incline at the piston  11  (see further down at  FIGS. 5 and 7 ). 
     In  FIG. 2 , the carriers  5  and the entire device for moving the upper mold component  20  relative to the lower mold component  30  along the stroke direction  6  are not shown because their type and arrangement are not significant for the invention. 
     In the shown exemplary embodiment, the first control component  16  is attached to the upper mold component  20  using a holding plate  24  and two screws. As an alternative, the first control component  16  and the holding plate  24  could also be designed of one piece or could be an integral component of the upper mold component  20 . 
     In the exemplary embodiment, two individual guide components  12   a ,  12   b  at a distance to each other and perpendicular to the stroke direction  6  are provided at the guide component  12  and are each fastened at the lower mold component  30  using two screws and have the piston  11  guided between them in the stroke direction  6 . The mirror-symmetric arrangement counteracts a canting of the movable parts against each other. 
     Both guide components  12   a ,  12   b  exhibit a respective slot  14 , for example in the shape of longitudinal holes. The rotational axis  13  that is connected to the piston  11  is guided in the corresponding slots  14 , whereby the relative stroke movement of the piston  11 , or of the hold-down element  18 , respectively, is limited toward the lower mold component  30  to a first specified path distance w 1  that is defined by the slot  14 . In other words, the extensions of the recesses  14  in the stroke direction  6  define the path that the work piece  4  together with the upper mold component  20  can pass away from the lower mold component  30 , until the hold-down element(s)  18  separate the work piece  4  from the upper mold component  20 . 
     In the presentation of  FIG. 3 , the mold  100  itself is also omitted such that only demolding devices  10  are shown in a perspective view at an angle from the front or at an angle from the back and the demolding devices  10  can be arranged in a preferred manner at a mold. It can be seen that the two essentially cuboidal control components  12   a ,  12   b  are kept at a distance to each other by a connecting component  12   c , such that a rectangular-shaped guide is created in-between. Of course, this guide may also have a different cross-sectional shape. The type of attachment can also be adapted to the requirements. 
     The second control component  19  is not as high as the guide components  12  such that a recess is created in the upper part. The spring element, or another actuator element, can be mounted in the area of this recess between the piston  11  and the lower mold component  30 , such that the spring element rests directly on the lower mold component  30 . Alternatively, the spring element can also rest on the guide component  12 , which in turn is arranged stationary at the lower mold component  30 . 
     In  FIG. 4 , the control edge  15  with the areas  15   a ,  15   b  are again shown as the significant features of the control component  16 . The area  15   a  defines the stroke of the stroke movement and thus how far the upper mold component  20  is moved out of the work piece before the rotational movement of the piston  11  and thus a full release of the work piece  4  is enabled due to the area  15   b.    
       FIG. 5  once again shows the piston  11  with a bore hole  21  for receiving the rotational axis  13 , as well as an incline  20  arranged at the lower end of the piston  11  that is pointing toward the lower mold component  30 . The incline  20  in interaction with a corresponding incline  17 . 1  at the second control component  17  supports the return rotation of the piston  11  and of the hold-down element  18  when the mold  100  closes to its initial position. Of course, similar to the area  15   b  of the control edge  15 , this incline can also exhibit a contour that deviates from the flat surface. 
       FIG. 6  once again shows in detail the hold-down element  18  with a mold draft  18  arranged at the edge that is pointing toward the upper mold component  20 . This narrowing serves the avoidance of a jamming of the hold-down element  18  in a recess  23  in the upper mold component  20 . 
       FIG. 7  once again shows the second control component  19  with an incline  19 . 1  that corresponds to the incline on the piston  11 . Preferably, this second control component  19  can be employed as a supplement to the first control component  16  for the rotational movement of the piston  11 . 
       FIG. 8 , finally once again shows the upper mold component  20  in a view from the bottom. The two recesses  21  for the two hold-down elements  18  can be recognized in it. One can also see that the upper mold component  20  exhibits a core  22  that protrudes into the lower mold component  30 . Furthermore, the Figure shows that the hold-down element  18  later rests partially on the core  22  such that after the production of the work piece  4 , the hold-down element  18  is arranged in this area in the stroke direction  6  between the upper mold component  20  and the lower mold component  30 . 
     Below, the movement sequences and the functionality of the mold  100  according to the invention will be explained with reference to  FIGS. 9 to 12 , each showing the mold from the same perspective viewing direction in various states. 
       FIG. 9  shows, in the same manner as  FIGS. 1 and 2 , the mold  100  with two demolding devices  10  in the fully closed position. In this position, the piston  11  is held by the control area  15   b  of the first control component  16  against the force of the spring element in an essentially parallel position to the stroke direction  6  and with that the hold-down element  18  in an essentially parallel position to the separation area between the upper mold component  20  and the lower mold component  30 . 
     When the mold  100  is opened, and in the process the upper mold component  20  is moved upwards along the stroke direction  6 , the following are moved upward at the same time: 
     The first control component  16 , because it is defined at the upper mold component  20 , 
     The hold-down element  18 , because it is “clamped” between the upper mold component  20  and the work piece  4  that is attached to it, 
     The piston  11 , because it is connected to the hold-down element  18 , and 
     The rotational axis  13 , because it in turn is connected to the piston  11 . 
     The state shown if  FIG. 10  is achieved. In this state, the mold halves  20 ,  30  are slightly separated from each other. The work piece  4  is already visible. In this first phase of the opening sequence of the mold  100 , the first control element  16  remains almost stationary in relation to the piston  11 , whereby also the area  15   a  of the control edge  15  remains positioned in front of the guide surface  11 . 1  at the piston  11  or even rests on it such that a pivoting motion of the piston  11  is not possible. 
     When the upper mold component  20  was moved upward by the first path distance w 1  (cf.  FIG. 1 ), which essentially is defined by the bore hold distance in the stroke direction  6  in the slot  14 , then the rotational axis  13  arrives at the stop at the upper end of the slot  14  and in this manner secures the piston  11  and the hold-down element  18  in the stroke direction  6  relative to the lower mold component  30 . 
     Thus, a relative movement between the upper mold component  20  and the hold-down element  18  occurs during the subsequent upwards movement of the upper mold component  20  in the stroke direction  6  due to the form-fitting stop of the rotational axis  13  at the upper end of its guide track, which in this case is formed by the slot  14 , and the hold-down element  18  that is connected via the piston  11  to the rotational axis  13 . This state is shown in  FIG. 11 . With the continued movement of the upper mold component  20  in the stroke direction  6  in the area of a second specified path distance w 2 , a relative movement now occurs in the stroke direction  6  between the first control component  16  and the piston  11 . The second path distance w 2  is essentially defined by the expanse of the area  15   a  in the stroke direction  6  at the first control component  16 . As long as the straight upper area  15   a  of the control edge  15  rests on the glide surface  11 . 1  at the piston, only a translatory movement in the stroke direction  6  is possible while a rotational movement of the piston  11  continues to be prevented.  FIG. 12  shows the state shortly after the area  15   a  of the control edge  15  no longer contacts the glide surface  11 . 1  and instead the set-off area  15   b  is located opposite the piston. 
     Only when the upper mold component  30  with the first control component  16  is moved upwards beyond the second path distance w 2 , the set-off area  15   b  that runs at an angle to the first area  15   a  allows rotational movement of the piston  11  away from the lower mold component  30  caused by the force of the actuator element. The geometric shape of the area  15   b  determines the amplitude and the angular speed of the pivoting movement. 
     Through the pivoting movement, the hold-down element  18 , which is connected to the piston  11 , is also moved away from the lower mold component  30 , such that the work piece  4  is fully released and can be removed from the mold  100 . The demolding device  10  can be dimensioned such that the second control component  16  can serve at any time as a stop for the rotational movement of the piston  11 . As an alternative, the second control component  16  can also be moved upwards sufficiently such that the piston  11  no longer contacts the control edge  15 . In this case, the lower mold component  20 , or the guide component  12 , respectively, serves as a stop to limit the rotational movement at the lower side of the piston  11 . 
     When closing the device  10  (after removing the work piece), the piston  11  is then turned back through the downwards movement of the upper mold component  20  against the force of the spring element through the area  15   b  of the control edge  15  in the direction of the lower mold component  30  and in this manner the hold-down element  18  is returned to its starting position. Thereafter, the upper mold component  20  is moved down by the second path distance w 2  until the first control component  16  comes in contact with the hold-down element  18  and returns the hold-down element and the piston  11  along the stroke direction  6  back into the starting position. 
     Thus, the first path distance w 1  defined by the recesses  14  defines the height by which the upper mold component  20  with the work piece  4  is lifted out of the lower mold component  20 , before the work piece  4  is separated from the upper mold component  20  with the aid of the hold-down element  18 . The height is defined by the length of the second path distance w 2  by which the upper mold component  20  is lifted out of the work piece  4 , before the hold-down element  18  is separated and the work piece  4  is fully released for removal. In this manner, the device  10  can be adapted variably to the dimensions of the upper mold component  20  in the stroke direction  6 . The shape of the area  15   b  additionally controls the rotational movement of the hold-down element  18 . This description of the functionality makes it clear that the invention is not determined by the concrete design of the individual parts and of the functional surfaces. Rather, the important aspect is the interaction of respective components such that the functional surfaces must correspond with each other. In the exemplary embodiment, which most likely corresponds to the most common practical application, the upper mold component  20  and the lower mold component  30  carry out a simple linear movement, whereby the stroke direction  6  extends vertically to the separation surface between upper mold component  20  and lower mold component  30 . The individual parts and the functional areas all run essentially parallel or perpendicular to the stroke direction  6 . Only the area  15   b  of the control edge  15  exhibits a progression that deviates from the vertical or parallel arrangement. 
     Essential for the invention is that the following interim steps are ensured: 
     The relative movement of the upper mold component  20 , work piece  4  and hold-down element  11  in relation to the lower mold component  30  in the stroke direction  6  in order to separate the work piece  4  from the lower mold component  30 , 
     The relative movement of the upper mold component  20  to the hold-down element  11  in the stroke direction  6  in order to separate the work piece  4  from the upper mold component and to move the upper mold component to a large degree or entirely out of the work piece, 
     The relative movement between the work piece  4  and the hold-down element  18  perpendicular to the stroke direction  6  in order to fully release the work piece  4 . 
     Particularly advantageous is the fact that the principle according to the invention is very easily adaptable to different molds  100  and work pieces  4 . Variable are in particular the length and the position of the recesses  14 , the position of the rotational axis  13 , the length and the shape of the control edge  15  as well as the length and the shape of the hold-down element  18 . In particular the hold-down element  18  with its end that is pointing towards the work piece  4  must be adapted to the shape of the work piece  4 , because this end forms a part of the mold  100  and in this manner has an influence on the contour of the work piece. 
       FIG. 13  shows a second embodiment of a demolding device  10 ′, which essentially has the same functionality as the embodiment described above, but has, however, a more compact design such that the demolding device  10 ′ can be arranged in particular also within the separation area between the mold components of a mold and does not need to be arranged on the sides on its outer edges. Thus, such an embodiment can also be used with multiple injection molding tools. The demolding devices  10 ′ can be arranged in the interim spaces between the individual cavities; in particular again in pairs at opposite sides of each cavity. 
       FIG. 13  shows an individual demolding device  10 ′. A first control element  16 ′ is formed cuboidal in the head area  16 . 1 ′, with rounded corners such that in the upper mold component a respective pocket for taking up the cuboidal section can be created easily using a milling cutter. 
     Following the head area  16 . 1 ′ is a wedge area  16 . 2 ′ which in turn exhibits a first area  15   a ′ of a control edge  15 ′, which is oriented parallel to the stroke direction  6 , and an additional set-off area  15   b ′, in particular at an angle, which can be recognized in  FIG. 16 . In the perspective view according to  FIG. 13  at an angle from below, one can additionally recognize that a piston  11 ′ also exhibits a head area  11 . 2 ′. In a hold-down element  18 ′, which here has a longitudinal design, a respective pocket for taking up the head area  11 . 2 ′ is milled in at the bottom side. 
     The piston  11 ′ additionally exhibits at the rear side that is pointing towards the viewer in  FIG. 13  several area sections  11 . 3 ′ to  11 . 6 ′. 
     The first area section  11 . 3 ′ runs parallel to the stroke direction and with the mold closed is oriented parallel to a pocket in the lower mold component  20 ′, in which the guide component  12 ′ can be inserted. The subsequent area section  11 . 4 ′ is slightly set back at an angle in relation to the area  11 . 3 ′ in order to enable the position of the piston  11 ′ that is slightly tipped backwards as shown in  FIG. 13 . Formed in the upper area of the piston, however, below the head area  11 . 2 ′, is a longitudinal hole  14 ′ in which a bolt element, serving as the rotational axis  13 ′ and positively arranged in the guide component  12 ′, is guided. In contrast to the first embodiment of the invention, where the bolts were arranged in the piston and the control components that were located outside exhibited the longitudinal hole, here an opposite arrangement has been selected. 
     The guide component  12 ′ has a basic configuration in the form of a longitudinal cuboid with strongly rounded corners. The curvature of the corners in turn serves the purpose of being able to easily create a respective pocket by milling in the lower mold component  30 ′ in which the control component can be inserted with an accurate fit. Through holes  12 . 4 ′ are used for attachments with the bottom of the pocket in the lower mold component. 
     In a rear area  12 . 3 ′ in  FIG. 13 , the control component is hollowed sufficiently that with the closed demolding device  10 ′, the wedge section  16 . 2 ′ of the control component  16 ′ can be received. In order to ensure when the upper mold component is returned to the lower mold component that the piston  11 ′ pivots back into its starting position and aligns itself again in the stroke direction  6 , in particular during the closing movement of the mold, similar to the first embodiment, an additional control component is implemented that here is designed as a lower extension  11 . 5 ′,  11 . 6 ′ of the piston  11 ′. The lower surface  11 . 6 ′ has a wedge-shaped design, thus, has a slanted surface in relation to the stroke direction  6 . In functional correlation with this is a bolt element  19 ′ that is inserted in the lower area of the guide element  12 ′. 
     In the open position of the demolding device shown in  FIG. 13 , the area  11 . 6 ′ rests on the bolt element  19 ′ and prevents the piston with the hold-down element  18 ′ from tilting to far outward. Once the closing movement of the mold starts, the control component  16 ′ presses on the piston  11 ′ via the hold-down element  18 ′ and thus pushes the piston downward. The surface  11 . 6 ′ glides down on the bolt  19 ′ until the surface  11 . 5 ′ is reached. This gliding movement of the surfaces  11 . 6 ′,  11 . 5 ′ on the bolt  16  has the effect that the piston  11 ′ is again oriented in the stroke direction and that the hold-down element is again oriented plane-parallel to the separation plane. 
     The movement sequence for the second embodiment is shown in  FIGS. 14 to 16 . 
       FIG. 14  shows the closed state with the upper mold component not shown. Indicated at the lower mold component  20 ′ is a partial area in order to indicate the recessed arrangement of the guide component  12 ′. The hold-down element  18 ′ is oriented plane-parallel to the separation plane  31 ′. The control component  16 ′ is moved down as far as possible such that its wedge area  16 . 2 ′ is received in the recess  12 . 3 ′ of the control component  12 . 
     In  FIG. 15 , the upward movement of the upper mold component has already started. Also the piston  11 ′ with the hold-down element  18 ′ has been lifted by the mold component (not shown here) and is still adhering to the upper mold component to an extent, until at the piston the rotational axis  13 ′ is located at the lower end of the longitudinal hole  14 ′. From here, further movement of the hold-down element  18 ′ is no longer possible such that with an additional upwards movement of the upper mold component only the work piece is stripped off. 
     With the continued upwards movement of the upper mold component, the control component  16 ′ also continues to be lifted up. The area  15   b ′ of the control edge no longer rests on the piston  11 ′ such that it can tilt to the outside appropriately. 
     With the second embodiment, the hold-down element  18 ′ can be balanced at the piston  11 ′ in relation to the rotational axis such that a heavier area is turned away from the cavity  32 ′. As soon as the forced guide of the piston and hold-down element is removed by the control component  16 , it can tilt away due to the greater outer mass, whereby this movement is limited by the surface  11 . 6 ′ that comes to rest at the bolt  19 ′. However, the actuator elements for bracing that have already been mentioned in connection with the first embodiment can be used as well. 
     There has thus been shown and described a novel demolding device for demolding a work piece from a mold which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.