Abstract:
A mold tool clamping device ( 30 ) for a blow mold comprising two mold halves ( 13  and  13 ). For fixing of the rear blow mold half to the clamp plate associated therewith, there is provided at least two wedge locks or cam locks, which are provided in a symmetric arrangement relative to the “vertical” transverse central plane of the rear mold tool, which are clampable with wedges, which, supported on the back side of the clamp plate, transverse to the longitudinal axis of the clamp bolts, are drivable into their anchor groove of anchor keyways, wherein these wedge locks are so arranged, that the wedges are drivable “from the side” into their clamp position in designed “grooves” of the clamp bolts complimentary thereto. This makes possible a rapid and positionally accurate securing of the rear mold half to its rear clamp plate.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention concerns a mold tool or segment clamping device for blow mold machines, in which a blow mold comprising two mold halves—mold tools—, which can be pushed together via a closure driver or actuator, in such a manner, that in the closed configuration of the blow mold they lie directly against each other along a central plane and are again separable from each other “symmetric to this central plane”, wherein as the closure actuator an electric or hydraulic linear actuator is provided, which engages on the “back” side of the clamp plate facing the drive and the further aggregates of the machine carrying machine frame, which clamp plate is synchronized via a synchronization drive with the “front” clamp plate on which the “front” mold tool is tightly clamped, is synchronized, the synchronization being in such a manner, that both mold halves are displaceable by a defined stroke relative to the blow mold central plane, and wherein for fixing the mold halves on their clamp plates these are provided with clamping bolts traversing these and connected resistant against pulling with the mold halves, which have anchoring end segments projecting or exiting from the clamp plates, which are engaged by the clamp elements, which respectively maintain the mold halves releasably fixed to the clamp plates which carry them. 
   2. Description of the Related Art 
   In the known blow mold machines of this type the blow mold halves are first secured to the front clamp plate in the closed configuration of the blow mold and then brought into that arrangement, in which the rear blow mold half is secured to the rear clamp plate—in the closed system. The securing occurs conventionally by anchor screws supported on the back side of the rear clamp plate, which are screwed onto clamp bolts which extend through the rear clamp plate, which are secured to the rear blow mold half. Alternatively, screws supported on the back side of the rear clamp plate are employed, which engage in threads in the rear blow mold half. 
   This type of securing is frequently tedious, since the intermediate space between the rear clamp plate and machine frame is difficult to access, so that the positionally accurate fixing of the rear blow mold half to its clamp plate is difficult and time consuming. 
   SUMMARY OF THE INVENTION 
   It is thus the task of the invention, to provide a tool clamping device, which makes possible a rapid and positionally accurate securing of the rear mold half to its rear clamp plate. 
   According thereto there is provided, for fixing of the rear blow mold half to the clamp plate associated therewith, at least two wedge locks or cam locks, which are provided in a symmetric arrangement relative to the “vertical” transverse central plane of the rear mold tool, which are clampable with wedges, which, supported on the back side of the clamp plate, transverse to the longitudinal axis of the clamp bolts, are drivable into their anchor groove or anchor keyways, wherein these wedge locks are so arranged, that the wedges are drivable “from the side” into their clamp position in designed “grooves” of the clamp bolts complimentary thereto. 
   In a preferred design of the clamping device the wedge lock pair supported on the clamp plate for fixing the mold halves is so designed that both wedges are operable “one handed” from one side of the clamp plate, whereby the fixing of the mold halves is simplified and the time required for the assembly is reduced. 
   A “collective” operation of both wedge locks of this type is realized in a preferred embodiment by means of a threaded spindle, wherein as a linear actuator for the displacement of the tensioning wedges of a wedge lock pair, a manual or motor driven spindle drive is provided, of which the rotationally actuatable threaded spindle has counter rotating threaded segments, which are in threaded engagement with appropriately counter rotating threads provided in glide stones rigidly connected with the wedges of the wedge blocks, which guide stones are mounted slidably relative to the clamp plates or in guide elements rigidly connected to the clamp plates. 
   In a preferred design of the wedge locks, these are so designed that the spindle threads are self-jamming, the wedge angle of the wedges however lies “outside” of the self-jamming amount. Thereby, the manipulation of the wedge locks is facilitated, which are tensionable and again releasable without significant expenditure of force, “by hand”. 
   By the design of the clamping bolt side wedge lock element as a T-groove, in which the groove wall, on which the wedge with its slant surface is supportable, is for its part running at the wedge angle, the slide block of the wedge however projects “axially” out between these groove walls through the central groove slit, is in combination with a perpendicular to the central axis of the clamping bolt running guide abutment, which supports itself on the plate or as the case may be a “parallel” guide block seated thereon, achieved, that in each engagement position of the wedge with the clamp bolts, pull or draw forces can be balanced or compensated for, without occurrence of a tilt action of the wedge. Herein the abutment is so designed—elongated on one side—, that it exactly or almost exactly balances the tilt moment caused by the wedge action. 
   In another preferred embodiment the wedge is guided on a guide block seated on the plate with its “L” guide element, which with respect to manufacturability is easier to achieve than to provide this guide element directly on the plate. 
   In yet another embodiment abutments or stops for limiting the float range of the wedge are provided on the glide blocks of the respective wedge lock pair, which limit the floating range in the unlocking direction. Thereby, in simple manner, a self-centering of the wedges of a wedge lock pair is achieved. 
   When, in an embodiment wherein the central axis of the spindle extends between the wedge surfaces of the clamp wedges of a wedge lock pair and are, perpendicular to the clamp bolt axis running, clamp plate fixed transverse guide surface, along which the clamp wedges of the wedge lock pair are slidable back and forth, the spindle axis runs between the wedge slant surface and the perpendicular to the bolt axis running guide surface of the wedge glide stone, it is achievable in simple manner, in combination with the “asymmetric” guiding of the wedge glide block, that the clamping process cannot result in a tilting or tipping of the wedge in the area of its slide surfaces, whereby also an easy opening—detensioning—of the wedge locks is ensured. 
   The type of floating mounting of the clamping bolts on the blow mold and the centering thereof by centering boreholes in the carrier plate when the clamp bolts are mounted floating in the radial direction on the mold tool and by the form fitting engagement with centering bore holes are therewith rigidly connected guide slope bring the clamp plate into the suitable position for clamping to the clamp plate accomplishes the advantage, that the T-groove shanks cannot widen and no amount of transverse force can be exercised upon the blow mold, since, by the form locking supporting of the bolts in the centering boreholes, a taking up of the radial transverse forces occurs solely by the plate. Thereby it is ensured that, during clamping of the wedge locks, no amount of forces act upon the mold halves which could lead to a displacement thereof relative to the clamping plate and/or to the complimentary mold half. 
   The design of the clamping device to the extent that the precentering of the bolts mounted floating on the blow mold occurs in a relatively wide or broad tolerant bore of the clamp plate and the fine centering occurs in a precise fine centering bore step, produces the advantage, that the blow mold—with utilization of the floating mounting of the bolts is easily seatable upon the clamp plate, since the precise positioning or orientation of the clamp bolts occurs substantially automatically. The provision of the fine centering bore on the guide block seated fixedly on the clamping plate is advantageous for manufacturing reasons. 
   When axially spring loaded bayonet mounts are provided for the radial floating mounting of the clamp bolts to their respective blow mold halves, the bolts are anchored on the mold tool by means of a spring biased bayonet lock or mount, which does not compromise the floating ability thereof, since the spring force acts only in the axial direction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further details of the inventive clamping device can be seen from the following description of a preferred embodiment on the basis of the figures. 
     There is shown: 
       FIG. 1  a locking system of a blow mold machine provided with the inventive mold tool clamping device in schematic simplified side view, 
       FIG. 2   a  the clamping device of the locking system according to  FIG. 1  in the clamped condition, seen in the direction of the arrow II a of  FIG. 1 , in partial sectional, schematic simplified representation, 
       FIG. 2   b  a view of a wedge lock of the clamping device according to  FIGS. 1 and 2   a , with a slide block as clamping element, which is guided slideable back and forth between the slit walls of a guide block, seen in the direction of the arrow II b of  FIG. 1 , 
       FIG. 2   c  the slide block of the wedge lock according to  FIG. 2   b , seen in the direction of the arrow II c of  FIG. 2   b,    
       FIG. 2   d  the slide block according to  FIG. 2   c , seen in the direction of the arrow II d of  FIG. 2   c,    
       FIG. 2   e  a side view of a clamping bolt of the lock according to  FIG. 2   a,    
       FIG. 2   f  a clamping bolt according to  FIG. 2   e  in section along the line IIf—IIf in  FIG. 2   e,    
       FIG. 3   a  a device for floating anchoring of a clamping bolt according to  FIGS. 2   e  and  2   f  in a sectional representation corresponding to  FIG. 2   c , and 
       FIG. 3   b  a view of a device according to  FIG. 3   a  in the direction of the arrow IIIb of  FIG. 3   a.   
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The locking system indicated overall with reference number  10  in  FIG. 1  represents a blow mold machine with which for example bottle shaped mold hollow bodies  11  can be blown. The blow mold provided therefore includes two mold halves—mold tools  12  and  13 —, which are respectively secured to one clamping plate  14  or as the case may be  16 . They can be pushed into the represented closed configuration of the blow mold by control of a hydraulic cylinder  17  of the lock system  10 , wherein the two mold tools  12  and  13  lie against each other along a vertical longitudinal central plane  20 , which is the common longitudinal central plane of a—not shown—blow station and a—likewise not shown—extrusion station of the blow mold machine, between which the blow mold carrying locking system  10  for receiving extruded tube shaped plastic pre-forms, as well as, and for blowing the mold hollow bodies back and forth is moveable. 
   The mold tool  12  and  13  carrying clamp plates  14  and  16  are provided between vertical upward projecting shanks  18 ,  19  of a basically C-shaped, upwardly open and overall with reference number  21  indicated frame of the closing system  10 . The frame  21  is shaped symmetric with reference to the vertical transverse central plane  22  ( FIG. 2   a ) of the closing system running at right angles to the vertical longitudinal central plane  20  of the blow mold and includes two “horizontal” guide spars or beams  23 , which extend approximately in the central height between the “horizontal” yoke or crib shank  24  of the frame  21  and the free end of its outer vertical shank  18  or as the case may be its inner vertical shank  19  and connects these with each other on both sides of the vertical cross sectional central plane  22 . 
   The rear clamp plate  16  provided facing the hydraulic cylinder  17  is connected fixed against pulling and pushing with the piston rod  27  of the hydraulic cylinder via a linkage  26  provided on its back side. The back clamp plate  16  is guided slideable back and forth “horizontally” on the guide beams or spars  23 . 
   The front clamp plate  14  and the rear clamp plate  16  are kinetically coupled with each other in known manner by means of a synchromesh gear or synchronized gear indicated overall with reference number  28 , in such a manner, that, beginning with the represented closed configuration of the blow mold, during an opening stroke of the piston rod  24  in the direction of the arrow  29  in  FIG. 1 , for both mold tools  12  and  13  there results in response a corresponding opening stroke by which the each other facing surfaces of the mold tool  12  and  13  become distant from the “machine fixed” longintudinal central axis  20  of the lock system  10 . 
   Also the front clamp plate  14 , which is provided on the side of the longitudinal central plane  20  opposite to the drive cylinder  17 , is guided slideably upon the guide beams or spars  23 , this however only for the purpose of being able to equalize or balance bending dependent separation—enlargements, which the free upper ends of the upward facing shanks  18  and  19  of the frame  21  experience, when the hydraulic cylinder  17  exercises a high closure force upon the closure system  10 . 
   For the releasable fixing of the rear blow mold half  13  on the rear clamp plate  16  which carries it there is provided a mold tool clamping device indicated overall with reference number  30 , which is provided on the rear side of the clamp plate  16  facing the hydraulic cylinder  17  and is operable by means of operating elements  31 , positioned on the side, for the tight clamping of the rear mold half  13  to the clamp plate  16  as well as for releasing the mold half  13  from the clamp plate  16 . 
   This operating or actuating element  31  can be seen in  FIG. 1  as rotation knobs projecting out from the side beyond the rear side of the clamp plate  16 , which are operable by hand “from outside”. 
   For a more detailed explanation of the clamping device  30  reference if now made to  FIGS. 2   a  through  2   f:    
   The clamping device  30  in the special embodiment selected for explanatory purposes, apart from the side orientation of their operating elements  31 , is designed symmetric as well with respect to the vertical longtudinal central plane  20  of the closure system as also with respect to the horizontal transverse central plane  22 , which runs parallel to the horizontal plane which is defined by the central axes  33  of the guide spars  23  and contains the thereto parallel linkage axis  34  of the linkage  26 , via which the piston rod  27  of the hydraulic cylinder  17  is coupled with the rear clamp plate fixed against pulling and pushing. 
   The clamping device  30  includes four wedge locks  36 , via the tension operation of which the rear mold tool  13  can be applied to its clamp plate  16 , of which respectively two are assembled to a wedge lock pair  37 /o and  37 /u, of which respectively one common linear drive device  38  is associated, through the manually or mechanically controlled operation of which both wedge locks  36 / 1  and  36 /r of the respective wedge lock pair  37 /o or as the case may be  37 /u are together tensionable and releasable. 
   The wedge locks  36 /l and  36 /r are designed or formed symmetric relative to the vertical transverse central plane  22  of the closure system  10  or as the case may be the rear clamp plate  16 , so that for explaining the construction of the wedge locks it is sufficient to explain this construction with reference to only one of them, which shall be the right wedge lock  36 /r on the basis of  FIG. 2 , which according to the representation of  FIG. 1  belongs to the upper part lock pair  37 /o, of which the clamp locks  36 /l and  36 /r represent that configuration in  FIG. 2   a , which corresponds to the tightly clamped condition of the rear mold half on the clamp plate  16 . 
   The wedge lock  36 /r includes, in the arrangement according to  FIG. 2 , a basically cylindrical clamp bolt  39 , which is anchored fixed against pulling in the rear mold half  13  with the orientation of its central longitudinal axis  43  extending perpendicular to the planar outer surface  41  of the inner mold half  13 , with which this lies against the planar outer surface  42  of the rear clamp plate  16 . The—cylindrical—clamp bolt  39  extends through or traverses with its central longitudinal axis  43  an axial bore  44  of the rear clamp plate  16 , of which the diameter is slightly larger than the diameter d of the clamp bolt  39 . 
   The clamp bolt  39  is extending through a central borehole  47  of a guide block indicated overall with the reference number  48 , which guide block  48  is fixed to the rear side of the rear clamp plate  16 , said clamp bolt  39  projecting with an anchoring segment indicated overall with reference number  46  ( FIG. 2   d ), into an otherwise longitudinal hole-shaped designed internal space  49  of the guide block  48 , which from the outside has the basic shape of a quadrilateral, which is seated fixedly in a flat or surface groove  51  provided on the back side of the rear clamp plate  16 , of which the groove floor  52  extends parallel to the vertical longitudinal central plane  20  and of which the groove walls  53  run parallel to the horizontal transverse central plane  32  of the closing system. 
   By means of not shown screws, which pass through the thick walled base area  54  of the guide block  48 , this guide block  48  is rigidly but releasably anchored to the rear clamp plate  16 . 
   The guide block  48  is designed to be symmetric with respect to its “horizontal” longitudinal central plane  56 , which runs parallel to the horizontal transverse central plane  32  of the closing system  10 . 
   The outwardly open internal space  49  of the guide block  48  is designed slit-shaped on both sides of the centering bore  47  wherein the two internal surfaces  57 / 1  and  57 / 2  of the longitudinal walls  58 / 1  and  58 / 2  of the guide block  48  which extend between stable transverse walls  59 / 1  and  59 / 2  of the guide block  48 , are arranged lying opposite to each other, and running parallel to the longitudinal central plane  56  of the guide block, thereby forming longitudinal guide surfaces and wherein the co-planar free end surfaces  61  of the longitudinal walls  58 / 1  and  58 / 2  of the guide block  48  the common plane of which coplanar surfaces  61  run parallel to the longitudinal central plane  20  of the closing system, form support surfaces for an overall with  62  indicated glide stone, which forms the clamp element, which by the sliding relative to the anchoring segment  46  of the clamp bolt  32  of the wedge lock  36 /r is tensionable—lockable—or, as the case may be, releasable. 
   As shown in the detailed representation of  FIG. 2   c , the glide stone  62  is designed symmetric relative to its longitudinal central plane  63  which in the “closed” configuration of the wedge lock  36 /r illustrated in  FIGS. 2   a  and  2   b  coincides with the longitudinal central plane of the guide block  48 . The glide stone  62  includes a support plate  64  of square or quadrilateral basic shape and a clamp shank  66 , having a base shape of a flat bar, projecting from the support plate  64  at a right angle “downwards”. The clamp shank joins with its one “outer” narrow end surface  67  ( FIG. 2   d ) flat against the one, outer transverse bordering surface  68  of the support plate  64  of the glide stone  62  and ends with a free, rectangular end surface  71  parallel to the free outer surface  61  of the support plate  64 . The breadth b s  measured between the outer narrow end surface  67  of the clamp shank  66  and its inner narrow end surface  72  is significantly smaller than the extension “length” l s  measured between the outer boundary surface  68  and the oppositely lying “inner” boundary surface  73  of the support plate—of the same, so that the support plate  64  has a “free support segment”  74  projecting on one side beyond the shank  66 . 
   In a base area  76  immediately adjacent the support plate  64  the glide stone  62  has a threaded bore  77 , of which the central axis  78 , seen in the closed condition of the wedge lock  36 /r intersects the central longitudinal axis  43  of the clamp bolt  39  perpendicularly and runs in the longitudinal central plane  56  of the guide block  48 . 
   A threaded spindle  79  is in engagement with the threaded bore  77  which extends through each other aligned bores  81 / 1  and  81 / 2  of the transverse walls  59 / 1  and  59 / 2  of the guide block  48 . By rotating the threaded spindle  79  by means of the actuating element  31  in alternative directions of rotation—clockwise and counterclockwise—the glide stone  62  is displaceable in the opposing directions represented by the arrows  82  and  83 , wherein the glide stone  62  is slidably guided by means of the longitudinal guide surfaces  84 / 1  and  84 / 2  of its base area  76  as well as the herewith respective coplanar longitudinal guide surfaces  86 / 1  and  86 / 2  of its free end segment  87  between the each other oppositely running internal surfaces  57 / 1  and  57 / 2  of the longitudinal walls  58 / 1  and  58 / 2  of the guide block  48 . Between the base area  76  and the free end segment  87  of the clamp shank  66  of the glide stone  63  there are machined-in respectively external open “wedge”—grooves, of which the groove base respectively runs in the plane  89 / 1  or as the case may be  89 / 2  parallel to the glide guide surfaces  84 / 1  and  86 / 1  or as the case may be  84 / 2  and  86 / 2 . 
   The planar walls  91 / 1  and  91 / 2  of the wedge grooves  88 / 1  and  88 / 2  adjacent to the free end surfaces  71  of the clamp shank—end segment  87  join at right angles respectively to the groove base surfaces  89 / 1  and  89 / 2  and extend, seen in the configuration of the wedge lock  36 /r according to  FIG. 2   a  between the narrow inner end surface  72  of the clamp shank  66  and its narrower outer end surface  67  diagonally increasing in such a manner that these groove walls  91 / 1  and  91 / 2  join with the free surface  71  of the clamp shank  66  at a wedge angle α of approximately 20°, so that the free end segment  87 / 1  forms on both sides of the bar  92  connecting the base portion  76  with the free end segment  87  two clamp wedges  93 / 1  and  93 / 2 , by driving of which into complementary designed anchor slits or grooves  94 / 1  and  94 / 2  ( FIG. 2   e ) of the clamp bolts  39  the wedge lock  36 /r is tensionable. 
   The clamp  39  is formed, in accordance with the detailed representation of  FIG. 2   e , symmetric relative to its “longitudinal”—central plane  96  which contains the central longitudinal axis  43  of the clamp bolt  39 , and which in the closed condition of the wedge lock  36 /r coincides or overlaps with the longitudinal central plane  63  of the glide stone  62 . 
   The two anchor grooves  94 / 1  and  94 / 2  provided similarly in the inside of the anchoring segment  46  of the clamping bolt  39  have as a “common” inner groove wall an inner end surface  97  running at a right angle to the longitudinal central plane  96 , and extending between planar parallel to each other running groove base surfaces  98 / 1  and  98 / 2 . The separation of these groove base surfaces  98 / 1  and  98 / 2  from each other is slightly larger than the distance of the longitudinal guide surfaces  84 / 1  and  84 / 2  of the base area  76  of the glide stone  62 , so that sufficient guide play is present, in order to be able to introduce the glide stone  62  with its clamp wedge  93 / 1  and  93 / 2  easily into the anchor groove  94 / 1  and  94 / 2  of the clamp bolt  39 . 
   These anchor grooves  94 / 1  and  94 / 2  of the clamp bolt  39  are set off from each other by a transverse slit  99 , of which—planar—slit walls  101 / 1  and  101 / 2  have a separation from each other, which is somewhat larger than the thickness of the bar  92 , which connects the base segment  76  of the glide stone  62  with the free end segment  87  of the clamp shank  66  forming the wedge  99 / 1  and  99 / 2 , but is significantly smaller than the separation of the longitudinal guide surfaces  86 / 1  and  86 / 2  of the wedge forming end segment  87  of the clamp shank  66  of the glide stone  62 , such that a sufficiently large surface overlapping of the clamp wedge surfaces  93 / 1  and  93 / 2  with the outer groove wall surfaces  102 / 1  and  102 / 2  of the clamp bolt  39  results, which likewise describe with the outer end surface  103  of the clamp bolt  93  ( FIG. 2   f ) an angle α of approximately 20°. 
   The wedge lock  36 /l shown in the left part of  FIG. 2   a  is constructionally the same as the wedge lock  36 /r shown on the right part of FIG.  2 . It differs with respect to its arrangement essentially therein, that it is rotated by 180°—“mirror image” with respect to the vertical transverse central plane  22 . In the illustrative embodiment selected for explanation the threaded bore  77  of the glide stone  62  is in threaded engagement with a right threaded—segment  104  of the threaded spindle  79 , while the thread bore  77  of the glide stone  62  of the “right” wedge lock  36 /r is in threaded engagement with a left threaded—segment  106  of the threaded spindle  79 . 
   By the rotation of the threaded spindle  79  via the rotation knob  39  in the counterclockwise direction represented by the directional arrow  107 , the glide stones  62  of both wedge locks  36 /l and  36 /r experience therewith a displacement in the direction of the arrows  83 , that is, away from each other, that is, in the sense of an opening of the wedge locks  36 /l and  36 /r. 
   These opening displacement movement of the glide stones  62  are limited by stops  108 , which are so arranged on the outer transverse walls  59 / 2 , that in the abutment limiting end position the rear mold half  13  can be easily removed without difficulty from the engagement position of its clamp bolts  39  with the centering bores  47  of the guide blocks  48  and the somewhat wider or broader transverse bores  44  of the rear clamp plate  16 . 
   On the other hand, when the threaded spindle  79  is rotated in the clockwise sense represented by the rotation arrow  109 , the glide stones  62  of both wedge locks  36 /l and  36 /r experience a towards each other directed displacement in the direction of the arrow  82 , which leads to the represented clamp position, in which the “slanted” wedge surfaces  91 / 1  and  91 / 2  of the clamp wedge  93 / 1  and  93 / 2  of the glide stones  62  with a, through the actuating force settable surface pressing, likewise lie against the diagonal counter-surface  101 / 1  and  101 / 2  of the clamp bolts. 
   The wedge angle α is selected to be slightly larger than the value α s  below which for a preselected pairing of the materials of which the clamp bolts  39  and the glide stones  62  are made, a self jamming fixing of the wedge locks  36 /l and  36 /r in the represented clamp position would be possible. In order at the same time to achieve a “self-jamming” fixing of the wedge locks  36 /l and  36 /r in the clamp position, the mutually engaging threads of the glide stones  62  and of the “counter-sense” threaded segments  104  and  106  are formed to be self-jamming. 
   By the design of the support plate  64  of the glide stone  62  with each other facing support plate projections  74  as well as the arrangement of the threaded spindle  79  between the clamp elements and the support plates  64  of the wedge stones, tilt movements which otherwise—during the clamping operation—could act upon the glide stones  62 , can be substantially compensated for or corrected or as the case may be balanced out, so that insofar no significant transverse forces are transmitted to the rear mold half  13 , which could lead to a misalignment between this and the rear clamp plate  16  and/or to a misalignment between the mold halves  12  and  13 . 
   The purpose of a substantial avoidance of such transverse forces or diagonal forces is also served by a “floating” anchoring of the clamp bolts  39  on the rear mold half  13 , in such a manner, that the clamp bolts  39  in the radial direction, that is, in all conceivable directions perpendicular to the central longitudinal axis  43  have sufficient play for deviating in their anchoring, when the respective clamp bolt  39  is introduced in the fine centering bore  47  of the respective guide block  48 , wherein this centering bore  47  widens with a diagonal inlet chamfer  111  to the diameter of the transverse bore  44  of the rear clamp plate  16  which is larger by the amount δ d ( FIG. 2   a ). 
   For explaining this floating anchoring now reference is made to  FIGS. 3   a  and  3   b . In accordance therewith the clamp bolt  39  is respectively received in a cylindrical-pot shaped recess  112  in the rear mold half, of which the diameter is somewhat larger than the length of a basically right angled burr  113 , which beginning from the anchoring end of the clamp bolt  39  extends flange shaped at a right angle therefrom. 
   The pot-shaped recess  112  has a circular round widening  114 , which is set off from the recess  112  by a ring shoulder  116 . In this widening  114  an anchoring ring  117  is seated or introduced and in the area of the ring shoulder  16  is screwed tight to the mold half  13 . The anchoring ring  117  has an inlet opening indicated overall with reference number  118  and having a contour which can be seen from  FIG. 3   b . This inlet opening is bordered circular round on other oppositely lying sector regions  119 , wherein the radius of this circular round edged opening area  119  is somewhat larger than the radius of the clamp bolt  39 . The opening sections  119  of circular shaped contour, the inlet opening  118  has substantially U-shaped recesses  121 , of which the middle plane  122  runs at a right angle to the middle plane  123  of the circular round edged region  119 . By the overall slit shaped inlet opening  118  the clamp bolt  39  can be introduced with its flange or burr  113  in the recess  112  of the rear mold half  13 . This introduction occurs against the return spring force of a return spring  124 , which is received in a central blind bore  126  of the clamp bolt  39  and basically supports itself on the base  127  of the recess  112 . 
   By rotating the clamp bolt about 90°, while the return spring is somewhat compressed, the flange or burr  113  can be brought into a position in which it can engage with mutually aligned “radial” inner groove  128  of the anchoring ring  117  and is held in this detent position by the pretensioned return spring  124 . The grooves  128  also have sufficient play, such that the floating anchoring of the clamp bolt  39  is ensured, which as a result provides for a decoupling of the clamp bolt engaging draw and tension forces and the transverse forces, respectively. 
   This type of anchoring corresponds to that of a spring loaded bayonet mount restrained with radial play.