Patent Publication Number: US-2009220636-A1

Title: Actuating Device for Shut-Off Needles in Injection Molding Machines Having Needle Valve Nozzles

Description:
The invention relates to an actuating device for shut-off needles in injection molds having needle valve nozzles, according to the preamble of Claim  1 , and an injection mold according to Claim  18 . 
     Needle valve nozzles are used in injection molds to feed a free-flowing composition, at a specifiable temperature under high pressure, to a removable mold insert. Needle valve nozzles usually have pneumatically, hydraulically, or electrically driven shut-off needles which periodically open and close the gate openings in the mold insert. For this purpose, each shut-off needle is mounted in the mold-side region of the injection molding machine in an axially displaceable manner, and in the nozzle-side region is preferably centrally guided through a flow channel for the composition to be processed. The flow channel ends in a nozzle end piece which forms a nozzle exit opening. In the closed position the lower end of the shut-off needle engages in a sealing seat provided in the nozzle end piece or in the mold insert. 
     To allow multiple needle valve nozzles to synchronously open and close in a mold, it is known from EP-A1-0 790 116, for example, to fix the shut-off needles on a common support plate which performs a lifting motion in the longitudinal direction of the shut-off needles. For this purpose the support plate is positioned on the end face side between two stationary stops, and is laterally positioned between two guide strips which are mounted inside a clamping plate in a longitudinally displaceable manner, and which on their lateral surfaces facing the support plate have obliquely oriented sliding blocks or sliding cams. The latter engage laterally in the support plate, which is provided with obliquely extending grooves. When the guide strips are pushed back and forth in the longitudinal direction by a drive, the support plate moves up and down, perpendicular thereto. 
     In an injection mold known from DE-A1-196 11 880 having multiple needle valve nozzles, each shut-off needle is fastened to a separate needle carrier element. At two opposite flat sides the latter are provided with obliquely oriented guide cams which engage in obliquely extending grooves in a fork-shaped sliding frame. Beneath the flat sides a cylindrical section is provided on each needle carrier element, which in the manner of a lifting piston is supported in a guide bush in an axially displaceable manner. When the sliding frame is moved back and forth, the individual needle carrier elements are moved up and down, perpendicular thereto. 
     DE-A1-199 07 116 discloses an actuating mechanism for die casting valve elements which is provided between two mold plates. The individual valve pins for a nozzle group are fixed to a common valve pin plate which is provided on the edges with guide bushes and which is able to slide up and down on guide pins extending parallel to the valve pins. Two actuating rods fastened to the valve pin plate bear multiple sliding blocks on the side. The latter engage in obliquely extending grooves in two cam elements which are mounted in a longitudinally displaceable manner between the upper mold plate and each respective retaining plate. 
     To prevent the lateral guide strips from jamming inside the actuating device, all components must be manufactured with exact tolerances and consistently positioned precisely within the mold. This is problematic in particular when the support plate or lifting plate has a relatively wide design. The farther apart the guide strips, the more likely the forward advancement of one or the other of the strips. This causes jamming of the components, which may result in malfunction or even damage. In addition, the support plate or valve pin plate cannot slide up and down precisely due to the nonuniform load on the oblique sliding blocks or sliding cams. 
     The object of the present invention is to provide a compact actuating device for injection molds having needle valve nozzles, which consistently moves all valve needles synchronously and acts on them with the same closing force. A particular aim is to achieve precise, consistently reliable guiding of the slide mechanism, in a design that is easy to manipulate and economical to implement. 
     The main features of the invention are stated in the characterizing part of Claim  1 , and in Claim  18 . Embodiments are the subject matter of Claims  2  through  17  and  19  through  27 . 
     In an actuating device for shut-off needles in injection molds having needle valve nozzles, and having at least one lifting element to which at least two shut-off needles may be fixed, and at least one actuating element which is mounted so that it is longitudinally displaceable in a first direction and which is coupled to the lifting element in such a way that a motion of the actuating element along the first direction is converted to a motion of the lifting element in a second direction transverse to the first direction, according to the invention the actuating element, which is slid in a guide unit along the first direction, is provided with an additional force-guided element. 
     In this manner consistently uniform and stable guiding of the actuating element is ensured. Jamming of the actuating element which moves back and forth in the first direction is thus prevented. The actuating device consistently operates in a precise and reliable manner, in a design that is easy to manipulate and economical to implement. 
     This is particularly the case when the force-guided element is provided parallel to the guide unit and/or as a linear guide. The motive forces are thus always introduced parallel to the direction of motion of the actuating element, so that the actuating element is always guided in a correct position. 
     With regard to design, it is advantageous for the force-guided element to have at least one guide element which is slid in a bearing, the guide element being a round bolt, rectangular bolt, or the like, which may be provided in a bearing in the form of a recirculating ball bushing, a self-lubricating bushing, or the like. 
     In a further practical embodiment, the force-guided element is designed as a flat guide. This ensures a low profile with optimal guiding characteristics, so that the actuating device may be easily accommodated in an injection mold even under limited space conditions. The guide element is preferably a flat element, block piece, sliding block, or the like, whereas the bearing is formed from two guide rails which accommodate the guide element in a sliding manner. In one alternative embodiment, the bearing is a ball bearing, needle bearing, or roller bearing, which likewise ensures low-friction and precise guiding of the flat element. 
     In a further design of the invention, the guide element and/or the bearing have a self-lubricating design. As a result, the actuating device is practically maintenance-free, which ensures consistently reliable operation. 
     In one refinement of the invention, the guide element is connected or fastened to the actuating element. In one advantageous embodiment, the actuating element has two sliding control rails, and at least two sliding elements are provided in grooves extending obliquely with respect to the first direction and the second direction, between the lifting element and the control rails, the sliding elements converting a motion of the control rails along the first direction to a motion of the lifting element in the second direction. It is practical for the actuating element or the control rails to be connected or connectable to a drive via a push element, so that only one central drive unit is necessary. 
     The guide element is advantageously attached to at least one control rail. Additionally or alternatively, however, the guide element may be fixed to the push element which connects the control rails to the drive. The entire actuating element is thus consistently guided in a precise manner by the flat guide; the guide element may also be designed as one piece with the push element. 
     A particularly precise and uniform motion is achieved when the guide element is provided or situated centrally with respect to the push element. The motive forces are thus always centrally introduced into the push element, which is particularly advantageous when the control rails have a symmetrical design with respect to the push element. The control rails are uniformly moved in a precise manner and are held in the correct position. Advancement of one rail or the other is no longer possible. Use of such a guide ensures consistently precise operation of the entire machine, and allows the lifting plate to be uniformly moved up and down from any position. Jamming or sticking of the slid components is effectively prevented. 
     In a further embodiment, at least two force-guided elements and/or two guide elements may be provided adjacent and parallel to one another. These elements as well are preferably symmetrically situated in the actuating device, thereby further increasing the overall precision and stability of guiding. 
     According to a further advantageous embodiment of the invention, the control rails may be connected to at least two additional control rails, between which at least one additional lifting element is provided. At least two additional shut-off needles may be fixed to this additional lifting element, which is connected to the additional control rails in such a way that a motion of the additional control rails along the first direction is converted to a motion of the lifting element in the second direction, transverse to the first direction. 
     Fixing the valve needles to the common lifting elements and connecting the control rails ensures that all valve needles are always moved synchronously and acted on with the same closing force. 
     The control rails are detachably connected to one another, thus allowing expansions to be made at any time and then returned to the original configuration. It is advantageous to provide the connection between the control rails as a plug-in or hook connection. A fixed connection between the control rails along the first direction is important in order to consistently actuate the lifting elements in a reliable manner. 
     To allow the actuating device and the valve needles to be individually adapted to the mold, the valve needles are designed to be adjustable relative to the lifting element, along the second direction. To also consistently ensure a synchronous adjustment motion with simultaneous compensation of motion, according to a further aspect of the invention the valve needles may be fixed to the lifting elements in an axially locked and radially floating manner. 
     In one special embodiment of the invention, the actuating device is provided in an injection mold, in particular in or on a clamping plate. For this purpose the clamping plate is provided with an indentation, for example, for accommodating the actuating device, thereby simplifying installation. 
     The bearing for the force-guided element, the same as for the guide unit, is preferably provided on or in the clamping plate, the guide unit being formed by the clamping plate itself or by at least two guide rails which are fastened on or in the clamping plate, and the control rails being slid between the guide rails. With regard to design it is also advantageous to provide the bearing for the force-guided element in the base of the clamping plate. The force-guided element thus occupies only a small space, which is also favorable for the profile height of the actuating device. 
     The guide unit for the actuating device has at least two guide rails which are fastened to or in the clamping plate, the control rails being slid between the guide rails. 
     To reduce the sliding friction of the actuating element within the guide unit, according to the invention the actuating element and/or the guide unit and/or the clamping plate have or bear sliding elements. These are preferably flat sliding strips or sliding plates which thus occupy little space, which is favorable for the profile height. Such elements may be easily and economically manufactured, quickly and conveniently installed, and replaced as needed. Particularly good friction characteristics are achieved when the sliding elements are made, at least partially, of a self-lubricating material or are at least partially coated with same. Additionally or alternatively, the sliding elements may also be designed as ball bearings, needle bearings, or roller bearings, or may be parts of such bearings. 
     Further significant advantages result when the actuating device is in flush abutment with the clamping plate. The profile height of the injection mold is not changed as a result. 
    
    
     
       Further features, particulars, and advantages of the invention result from the text of the claims and the following description of exemplary embodiments with reference to the drawings, which show the following: 
         FIG. 1  shows a top view of one embodiment of an actuating device for injection molds; 
         FIG. 2  shows a top view of a further embodiment of an actuating device for injection molds; 
         FIG. 3  shows an oblique view of a further embodiment of an actuating device for injection molds; 
         FIG. 4  shows the actuating device of  FIG. 3  without a lifting plate; and 
         FIG. 5  shows a detailed illustration of a push element. 
     
    
    
     The actuating device denoted in general by reference numeral  10  in  FIG. 1  is provided for the actuation of multiple shut-off needles  16  in an injection molding machine (not further illustrated). The injection molding machine is used for producing molded parts from a free-flowing composition, for example a plastic melt. To this end, multiple needle valve nozzles (not illustrated) are provided beneath a distribution plate (likewise not illustrated). The needle valve nozzles conduct the plastic melt to be processed to a removable mold insert (likewise not illustrated), the gate openings of the mold insert being periodically opened and closed by the shut-off needles  16 . Located above the distribution plate is a clamping plate  12 , which is provided for accommodating the actuating device  10  in an essentially rectangular depression or recess  13 . 
     To allow the shut-off needles  16  for the needle valve nozzles to be simultaneously actuated, a lifting element  20  is provided on which at least two shut-off needles  16  are fastened. The lifting element  20  is designed as a rectangular plate, for example, which is parallel to the clamping plate  12  and which on its long side is connected to an actuating element  30  which is mounted so that it is longitudinally displaceable in a first direction R 1 , whereby a motion of the actuating element  30  along the first direction R 1  is converted to a motion of the lifting element  20  in a second direction R 2  transverse to the first direction R 1 . For this purpose the lifting plate  20  bears two sliding elements  21 , one on each side, which are slid in parallel in the actuating element  30 . To this end, the lateral surfaces of the actuating element facing the lifting plate  20  are provided with respective grooves  40  which extend at an angle with respect to the clamping plate  12  and accommodate the sliding elements  21  with a slight amount of play. 
     The actuating element  30  is formed by two displaceably mounted control rails  31  situated on each side of the lifting plate  20 . The lifting plate rests with its end face between stationary stops  60 ,  62 , which are fixed in the depression  13  in the clamping plate  12  by means of screws  63 . Alignment pins  66  provide precise alignment of the stops  60 ,  62 , which preferably have a rectangular cross section, the pins  66  being securely fixed in the clamping plate  12  and accommodated with an exact fit in boreholes (not further described) in the stops  60 ,  62 . 
     The control rails  31  are slid inside the depression  13  in a guide unit  90 , and are connected to a drive  80  via a common push element  82  and an adapter piece  86  (not visible in  FIG. 1 ). The adapter piece is preferably externally fastened to the clamping plate  12 , and is guided through the clamping plate  12  through an opening or recess (not illustrated) on the end face side. The drive  80  may be an electric, pneumatic, or hydraulic actuating drive or motor which is preferably actuated by a control electronics system (likewise not shown). The connection between the push element  82  and the adapter piece  86  forms a sliding block  88  having a T-shaped cross section which, likewise without a tool, is inserted into the push element  82  in a form-fit manner. For this purpose the push element is provided with a cutout  89 . The sliding block  88  is secured to the adapter piece by a spring dowel pin  87 . 
     Each control rail  31  has a hook-shaped end  33  on the drive side which may be laterally engaged with the push element  82 . For this purpose the push element has two step-shaped ends  83  which are accommodated in a form-fit manner by the hooks  33  for the control rails  31  directed inwardly and perpendicular to the first direction R 1 . This results in a connection which is always secure in the first direction R 1  and which may be released perpendicularly thereto. Components  31 ,  82  of the actuating element  30  may thus be quickly installed and removed at any time when a longer and/or wider lifting plate  20 , for example, is used. During installation the elements  31 ,  82  may be easily placed one inside the other without a tool, forming a U-shaped assembly in the installed state which is securely joined together. The entire actuating device  10  may be manipulated very easily, and the installation costs are minimal. 
     The guide unit  90  is formed either by the clamping plate  12  or by at least two separate guide rails  91 . The guide rails rest laterally in the depression  13  in the adapter plate  12 . The guide rails are fastened by screws to the base  14  of the depression  13 , and at each lateral surface facing the control rails  31  are provided with a continuous guide groove (not visible) extending parallel to the adapter plate  12 . Each guide groove accommodates a sliding strip (likewise not shown) with a small amount of play, the sliding strip being provided on a lateral surface of the control rail  31  facing one of the guide rails  91 . 
     Alignment pins  96  (not further described) provide precise alignment of the guide rails  91  inside the depression  13 . The alignment pins are fixedly inserted in the base  14  of the clamping plate  12 , and are accommodated with an exact fit by boreholes (not further described) in the guide rails  91 . 
     In the alternative embodiment illustrated in  FIGS. 3 and 4 , the guide rails  91  bear two sliding plates  93  at their lateral surfaces  92  facing the control rails  31 , the sliding plates preferably being coated with a self-lubricating material or made of same. 
     It is shown that the actuating element  30 , comprising the control rails  31  and the push element  82 , which is slid in direction R 1  forms a U-shaped insertion frame which laterally encloses the lifting plate  20  with a slight amount of play and is slid inside the guide unit  90 . To further reduce the sliding friction within the actuating device  10 , the control rails  31  are provided at the top and bottom with sliding plates  35  which are either made of a self-lubricating material or are at least partially coated with same. The sliding plates  35  for the control rails  31  together with the sliding plates  93  for the guide rail form sliding elements, thus allowing the actuating element  30  to be moved back and forth with little expenditure of force. Additionally or alternatively, the sliding elements  35 ,  93  may also be designed as sliding strips or as ball bearings, needle bearings, or roller bearings. However, the sliding elements may also be components of ball bearings, needle bearings, or roller bearings. 
     As further shown in  FIG. 1 , additional control rails  131  may be connected to the control rails  31 . Situated between same, parallel to the clamping plate  12 , is an additional lifting element  120 , which in the form of a rectangular plate having the same width adjoins the first lifting plate  20 , and to which additional shut-off needles  116  are fastened. Both plates  20 ,  120  together rest in the longitudinal direction between the stationary stops  60 ,  62 . 
     For connecting the additional control rails  131  to the control rails  31 , the ends  34  of the control rails  31  facing away from the push element  82  and the ends  133  of the additional control rails  131  facing the drive  80  likewise have a hook-shaped design, the hook ends  34  of the control rails  31  and the hook ends  133  of the additional control rails  131  having congruent shapes and respectively pointing in the opposite direction, perpendicular to the first direction R 1 . The hooks  34 ,  133  engage with one another in a form-fit manner, resulting in a connection which is always fixed in the first direction R 1  and which may be released in the direction perpendicular thereto. 
     In this manner the control rails  31 ,  131  may be quickly and easily joined together at the ends  34 ,  133  by simple latching or insertion. The actuating device  10  may thus be expanded by additional lifting plates  120  at any time without great effort by fastening or connecting additional control rails  131  to the control rails  31  already present. The additional control rails are connected to the drive  80  via the control rails  31  and the push element  82 , so that an additional drive unit is not necessary. This is also very advantageous for the mold costs. 
     The additional lifting plate  121 , the same as the lifting plate  21 , bears sliding elements, one on each side, which are slid in parallel in the control rails  131 . The lateral surfaces of the control rails facing the lifting plate  120  are provided with respective grooves  140  which extend at an angle with respect to the clamping plate  12  and accommodate the sliding elements with a slight amount of play. The additional control rails  131  are likewise slid longitudinally between two stationary guide rails  91  for the guide unit  90 . 
     When the drive  80  periodically moves the frame  30  back and forth in the first direction R 1 , lifting plates  20 ,  120  which are forcibly guided between the stops  60 ,  62  by the sliding elements in the oblique grooves  40 ,  140  in the control rails  31 ,  131  are moved up and down in the second direction R 2 , which is preferably perpendicular to direction R 1 . The lifting plates  20 ,  120  which planarly adjoin one another at their end faces (not further described), together with the shut-off needles  16 ,  116  fixed thereto, thus perform a synchronous lifting motion, all shut-off needles  16 ,  116  being consistently actuated at the same time and with the same actuating force. 
     To prevent the U-shaped actuating element  30  from jamming between the lifting plates  20 ,  120  and the guide unit  90  during operation, parallel to the guide rails  91  a force-guided element  50  is provided which additionally guides the actuating element  30  along direction R 1 . The force-guided element  50  is preferably designed as a linear guide. The force-guided element has a respective oblong guide element  52 , symmetrically provided on each side of the drive  80 , which is forcibly guided in a bearing  54 . 
     The guide elements  52  are round bolts, for example, which by means of screws  53  are fastened to the push element  82 . To ensure a precise perpendicular alignment of the bolts  52  above the end face  84  of the push element  82  facing the drive  80 , blind holes (not further described) are provided in the push element which accommodate the bolts  52  with an exact fit. The bolts are always parallel to direction R 1 , and project through the end face  15  of the clamping plate  12  facing the drive  80 . 
     Each bearing  54  is a recirculating ball bushing, for example, which is inserted into the end face of the clamping plate  12  and accommodates the associated guide bolts  52  with the least possible amount of play. The guide bolts  52  are always precisely guided inside the recirculating ball bushings  54 , which likewise are aligned parallel to direction R 1 , so that the sliding frame  30  by necessity must be precisely guided in direction R 1 . Thus, jamming of the pusher  30  with respect to the lifting plates  20 ,  120  and/or the guide rails  91  is essentially prevented. The actuating device  10  ensures consistently precise and uniform guiding of the frame  30  in the guide unit  90 . 
     In the embodiment in  FIGS. 3 through 5 , the force-guided element  50  designed as a linear guide has a guide element  52 , centrally located with respect to the drive  80 , which is slid in a bearing  54 . The bearing is formed by two guide rails  56  which are inset in the base  14  of the clamping plate  12  and securely screwed at that location. 
     As shown in particular in  FIG. 5 , the guide element  52  is designed as an oblong flat element, provided in one piece with the push element  82 . The guide element is situated exactly in the middle of the push element  82 , and is therefore centrally located between the control rails  31 . Lateral grooves  57  on both sides of the flat element  52  accommodate lubricant which minimizes the sliding friction inside the bearing  54 . The overall assembly is therefore essentially maintenance-free. 
     The guide element  52  is guided precisely between the guide rails  56  for the bearing  54 ; i.e., the push element  82  cannot become jammed or twist inside the device  10 . This ensures that the control rails  31  symmetrically positioned with respect to the force-guided element  50  are always moved synchronously and parallel to direction R 1 . Therefore, the entire sliding frame  30  by necessity must move precisely in direction R 1 . Jamming of the pusher  30  with respect to the lifting plate  20  and/or the guide rails  91  is thus prevented. The actuating device  10  ensures consistently precise and uniform guiding of the frame  30  in the guide unit  90 . 
     To ensure that the lifting plates  20 ,  120  perform a defined and consistently reproducible lifting motion, the motion of the push element  82  in the first direction R 1  is limited by stops. The clamping plate  12  forms a first stop, whereas the stop  60  facing the drive  80  forms a second stop. The distance between the end face wall  15  and the stop  60  specifies the actuating distance for the push element  82 , and thus for the control rails  31 ,  131 , which consequently may be moved back and forth between at least two defined positions. The lifting plates  20 ,  120 , regardless of the inclination of the grooves  40 ,  140  and the sliding elements, perform a correspondingly defined lifting motion, whereby targeted intermediate positions may also be attained via the drive  80  when, for example, the shut-off needles  16 ,  116  are to be brought into various closed and open positions. 
     The detachable plug-in connections between components  31 ,  82  and  82 ,  88  and  31 ,  131  have the advantage that the actuating device  10  may be quickly and easily installed from above in the recess  13  in the stop plate  12 . Only the stops  60 ,  62  are already inserted in the depression  13 . The entire actuating device  10  is thus composed of very few parts which have a simple geometry. The actuating device is very easy to install and may be expanded at any time. Conversely, the lifting elements  20 ,  120 , the control rails  31 ,  131 , the push element  82 , and the guide rails  91  may be quickly and easily removed from the clamping plate  12  at any time, for example to exchange defective components, to replace the shut-off needles  16 ,  116 , or to perform other maintenance activities. 
     The shut-off needles  16 ,  116  are inserted into the lifting plates  20 ,  120  from above, the lifting plates being provided with boreholes (not further described). In the region of the lifting plates  20 ,  120  each needle  16 ,  116  has threading on the end which is screwed into an essentially rectangular retaining plate (not visible). An adjusting nut (likewise not further described) fixes the needle  16 ,  116  in place with respect to the retaining plate, which lies flat on the lifting plate  20 ,  120 . In this manner the needles  16 ,  116  may be individually adjusted in length relative to the lifting plate  20 ,  120 , along the second direction R 2 . 
     Each retaining plate rests in a cutout (likewise not shown) whose height essentially corresponds exactly to the height of the retaining plate, and whose outer dimensions are larger than those of the retaining plate, so that the retaining plate may be moved radially inside the cutout. A cover plate  25  fastened to the lifting plate  20  by screws  26  secures the retaining plate in the cutout. The retaining plate is thus fixed in the axial direction of the shut-off needles  16 ,  116  with the least possible amount of play between the lifting plate  20 ,  120  and the cover plate  25 , so that all needles  16 ,  116  may be consistently brought into the closed position and reopened in a precise manner. On the other hand, in the radial direction the retaining plates are supported in a floating manner, thereby compensating for deflections of the needles  16 ,  116  inside the hot runner nozzles. The shape of the retaining plate also rotationally fixes the needles  16 ,  116  relative to the lifting plate  20 . 
     The adjusting nuts  18  of the needles  16 ,  116  project through the cover plates  25 . To prevent the ends of the needles from projecting too far beyond the lifting plates  20 ,  120 , the retaining plates and the cover plates  25  rest in depressions  24  introduced into the lifting plates  20 ,  120  from above. The profile height of the actuating device  10  thus remains small. 
     The lifting plates  20 ,  120  form a central recess  70  in the middle (see  FIG. 1 ) which continues with the same inner diameter into the clamping plate  12 . The recess  70  implements a flow channel of a distribution arm or the like, in particular a machine nozzle or sprue bush (not illustrated), which provides the distribution plate situated below the clamping plate  12  with the plastic composition to be processed. The inner diameter (not further described) of the recess  70  is dimensioned such that the lifting plates  20 ,  120  are able to move unhindered. The single lifting plate  20  has a centrally located recess  70  (see  FIG. 3 ) which continues with the same inner diameter into the clamping plate  12 . This recess  70  as well implements a flow channel of a distribution arm or the like, in particular a machine nozzle or sprue bush (not illustrated). 
     The end of the actuating device  10  forms a cover plate (not illustrated) which lies flat on the guide rails  91  and is secured thereto by screws (likewise not shown). The cover plate  19  secures all plug-in connections and preferably is in flush abutment with the top side of the clamping plate  12 , thus preventing the actuating device  10  from projecting beyond the clamping plate  12 . Instead, the device  10  is essentially completely integrated into the clamping plate  12 , which is very favorable for the profile height of the mold. Only the drive  80  is externally located on the clamping plate  12 , but this has no effect on the profile height thereof. 
     In the embodiments of  FIGS. 1 and 2  a total of thirty-two shut-off needles  16  are fastened to the lifting elements  20 ,  120 . However, the number of shut-off needles  16  may be easily increased or decreased by providing the lifting plates  20 ,  120  with an appropriate design. For optimal utilization of the mold area provided, multiple mold inserts and therefore multiple needle valve nozzles may be situated very close to one another. 
     Two actuating devices  10  may also be positioned side by side. For this purpose, the clamping plate  12  is provided with two adjacent depressions  13  or a common depression, so that the control rails  31 ,  131  and the guide rails  91  for the individual actuating devices  10  are parallel and adjacent to one another. 
     The invention is not limited to any one of the embodiments described above, and may be modified in various ways. Thus, alternatively or additionally the guide element  52  for the force-guided element  50  may be attached directly to a control rail  31 . This may involve the use of a rectangular bolt if needed. The bearing  54  may be designed as a self-lubricating bush which accommodates the bolt  52  with an exact fit and the least possible amount of play. 
     The control rails  31  and the push element  82  as well as the control rails  31 ,  131  may also be joined together in a force-fit manner, for example by means of locking elements (not shown). In addition, the lifting elements  20 ,  120  may be detachably connected to one another. The retaining plates for the shut-off needles  16 ,  116  may be designed as disks which are flattened at two opposite sides. 
     The ends (not further described) of the additional control rails  131  facing away from the drive  80  may likewise have a hook-shaped design to allow further control rails to be connected. These hook ends also have a shape that is congruent with the hook ends  33 ,  34 ,  133 , and have a design resulting in a connection with consistently high tensile strength which may be detached in the direction perpendicular thereto. 
     The entire actuating device  10  may thus be designed as a modular system which may be individually and flexibly assembled using a small number of base elements  20 ,  30 ,  50 ,  120 ,  90 . All components may be quickly joined together by simple latching or insertion, and may be disconnected as needed. The control rails  31  are provided on both sides with hook-shaped ends, which simplifies manufacture. The actuating device  10  may thus be expanded at any time without great effort, or adapted to a different requirement. 
     All features and advantages resulting from the claims, description, and drawings, including design details, spatial configurations, and method steps, may be essential to the invention, as such or in various combinations. 
     LIST OF REFERENCE NUMERALS 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 R1 
                 First direction 
               
               
                 R2 
                 Second direction 
               
               
                 10 
                 Actuating device 
               
               
                 12 
                 Clamping plate 
               
               
                 13 
                 Depression/recess 
               
               
                 14 
                 Base 
               
               
                 15 
                 End face 
               
               
                 16 
                 Shut-off needle 
               
               
                 17 
                 Opening 
               
               
                 20 
                 Lifting element/lifting plate 
               
               
                 21 
                 Sliding element 
               
               
                 22 
                 Lateral surface 
               
               
                 23 
                 Recesses 
               
               
                 24 
                 Depression 
               
               
                 25 
                 Cover plate 
               
               
                 26 
                 Screw 
               
               
                 30 
                 Actuating element 
               
               
                 31 
                 Control rail 
               
               
                 33 
                 Hook-shaped end 
               
               
                 34 
                 Hook-shaped end 
               
               
                 40 
                 Groove 
               
               
                 46 
                 Screws 
               
               
                 47 
                 Screws 
               
               
                 50 
                 Force-guided element 
               
               
                 52 
                 Guide element 
               
               
                 54 
                 Bearing 
               
               
                 56 
                 Guide rail 
               
               
                 57 
                 Screw 
               
               
                 60 
                 Stop 
               
               
                 62 
                 Stop 
               
               
                 63 
                 Screw 
               
               
                 66 
                 Alignment pin 
               
               
                 70 
                 Recess 
               
               
                 80 
                 Drive 
               
               
                 82 
                 Push element 
               
               
                 83 
                 Step-shaped end 
               
               
                 84 
                 End face 
               
               
                 86 
                 Adapter piece 
               
               
                 87 
                 Spring dowel pin 
               
               
                 88 
                 Sliding block 
               
               
                 89 
                 Cutout 
               
               
                 90 
                 Guide unit 
               
               
                 91 
                 Guide rail 
               
               
                 92 
                 Screw 
               
               
                 96 
                 Alignment pin 
               
               
                 116  
                 Shut-off needle 
               
               
                 120  
                 Lifting element/lifting plate 
               
               
                 131  
                 Control rail 
               
               
                 133  
                 Hook-shaped end 
               
               
                 140  
                 Groove