Mold tool clamping device for blow mold machines

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.

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.

DETAILED DESCRIPTION OF THE INVENTION

The locking system indicated overall with reference number10inFIG. 1represents a blow mold machine with which for example bottle shaped mold hollow bodies11can be blown. The blow mold provided therefore includes two mold halves—mold tools12and13—, which are respectively secured to one clamping plate14or as the case may be16. They can be pushed into the represented closed configuration of the blow mold by control of a hydraulic cylinder17of the lock system10, wherein the two mold tools12and13lie against each other along a vertical longitudinal central plane20, 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 system10for receiving extruded tube shaped plastic pre-forms, as well as, and for blowing the mold hollow bodies back and forth is moveable.

The mold tool12and13carrying clamp plates14and16are provided between vertical upward projecting shanks18,19of a basically C-shaped, upwardly open and overall with reference number21indicated frame of the closing system10. The frame21is shaped symmetric with reference to the vertical transverse central plane22(FIG. 2a) of the closing system running at right angles to the vertical longitudinal central plane20of the blow mold and includes two “horizontal” guide spars or beams23, which extend approximately in the central height between the “horizontal” yoke or crib shank24of the frame21and the free end of its outer vertical shank18or as the case may be its inner vertical shank19and connects these with each other on both sides of the vertical cross sectional central plane22.

The rear clamp plate16provided facing the hydraulic cylinder17is connected fixed against pulling and pushing with the piston rod27of the hydraulic cylinder via a linkage26provided on its back side. The back clamp plate16is guided slideable back and forth “horizontally” on the guide beams or spars23.

The front clamp plate14and the rear clamp plate16are kinetically coupled with each other in known manner by means of a synchromesh gear or synchronized gear indicated overall with reference number28, in such a manner, that, beginning with the represented closed configuration of the blow mold, during an opening stroke of the piston rod24in the direction of the arrow29inFIG. 1, for both mold tools12and13there results in response a corresponding opening stroke by which the each other facing surfaces of the mold tool12and13become distant from the “machine fixed” longintudinal central axis20of the lock system10.

Also the front clamp plate14, which is provided on the side of the longitudinal central plane20opposite to the drive cylinder17, is guided slideably upon the guide beams or spars23, 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 shanks18and19of the frame21experience, when the hydraulic cylinder17exercises a high closure force upon the closure system10.

For the releasable fixing of the rear blow mold half13on the rear clamp plate16which carries it there is provided a mold tool clamping device indicated overall with reference number30, which is provided on the rear side of the clamp plate16facing the hydraulic cylinder17and is operable by means of operating elements31, positioned on the side, for the tight clamping of the rear mold half13to the clamp plate16as well as for releasing the mold half13from the clamp plate16.

This operating or actuating element31can be seen inFIG. 1as rotation knobs projecting out from the side beyond the rear side of the clamp plate16, which are operable by hand “from outside”.

For a more detailed explanation of the clamping device30reference if now made toFIGS. 2athrough2f:

The clamping device30in the special embodiment selected for explanatory purposes, apart from the side orientation of their operating elements31, is designed symmetric as well with respect to the vertical longtudinal central plane20of the closure system as also with respect to the horizontal transverse central plane22, which runs parallel to the horizontal plane which is defined by the central axes33of the guide spars23and contains the thereto parallel linkage axis34of the linkage26, via which the piston rod27of the hydraulic cylinder17is coupled with the rear clamp plate fixed against pulling and pushing.

The clamping device30includes four wedge locks36, via the tension operation of which the rear mold tool13can be applied to its clamp plate16, of which respectively two are assembled to a wedge lock pair37/o and37/u, of which respectively one common linear drive device38is associated, through the manually or mechanically controlled operation of which both wedge locks36/1and36/r of the respective wedge lock pair37/o or as the case may be37/u are together tensionable and releasable.

The wedge locks36/l and36/r are designed or formed symmetric relative to the vertical transverse central plane22of the closure system10or as the case may be the rear clamp plate16, 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 lock36/r on the basis ofFIG. 2, which according to the representation ofFIG. 1belongs to the upper part lock pair37/o, of which the clamp locks36/l and36/r represent that configuration inFIG. 2a, which corresponds to the tightly clamped condition of the rear mold half on the clamp plate16.

The wedge lock36/r includes, in the arrangement according toFIG. 2, a basically cylindrical clamp bolt39, which is anchored fixed against pulling in the rear mold half13with the orientation of its central longitudinal axis43extending perpendicular to the planar outer surface41of the inner mold half13, with which this lies against the planar outer surface42of the rear clamp plate16. The—cylindrical—clamp bolt39extends through or traverses with its central longitudinal axis43an axial bore44of the rear clamp plate16, of which the diameter is slightly larger than the diameter d of the clamp bolt39.

The clamp bolt39is extending through a central borehole47of a guide block indicated overall with the reference number48, which guide block48is fixed to the rear side of the rear clamp plate16, said clamp bolt39projecting with an anchoring segment indicated overall with reference number46(FIG. 2d), into an otherwise longitudinal hole-shaped designed internal space49of the guide block48, which from the outside has the basic shape of a quadrilateral, which is seated fixedly in a flat or surface groove51provided on the back side of the rear clamp plate16, of which the groove floor52extends parallel to the vertical longitudinal central plane20and of which the groove walls53run parallel to the horizontal transverse central plane32of the closing system.

By means of not shown screws, which pass through the thick walled base area54of the guide block48, this guide block48is rigidly but releasably anchored to the rear clamp plate16.

The guide block48is designed to be symmetric with respect to its “horizontal” longitudinal central plane56, which runs parallel to the horizontal transverse central plane32of the closing system10.

The outwardly open internal space49of the guide block48is designed slit-shaped on both sides of the centering bore47wherein the two internal surfaces57/1and57/2of the longitudinal walls58/1and58/2of the guide block48which extend between stable transverse walls59/1and59/2of the guide block48, are arranged lying opposite to each other, and running parallel to the longitudinal central plane56of the guide block, thereby forming longitudinal guide surfaces and wherein the co-planar free end surfaces61of the longitudinal walls58/1and58/2of the guide block48the common plane of which coplanar surfaces61run parallel to the longitudinal central plane20of the closing system, form support surfaces for an overall with62indicated glide stone, which forms the clamp element, which by the sliding relative to the anchoring segment46of the clamp bolt32of the wedge lock36/r is tensionable—lockable—or, as the case may be, releasable.

As shown in the detailed representation ofFIG. 2c, the glide stone62is designed symmetric relative to its longitudinal central plane63which in the “closed” configuration of the wedge lock36/r illustrated inFIGS. 2aand2bcoincides with the longitudinal central plane of the guide block48. The glide stone62includes a support plate64of square or quadrilateral basic shape and a clamp shank66, having a base shape of a flat bar, projecting from the support plate64at a right angle “downwards”. The clamp shank joins with its one “outer” narrow end surface67(FIG. 2d) flat against the one, outer transverse bordering surface68of the support plate64of the glide stone62and ends with a free, rectangular end surface71parallel to the free outer surface61of the support plate64. The breadth bsmeasured between the outer narrow end surface67of the clamp shank66and its inner narrow end surface72is significantly smaller than the extension “length” lsmeasured between the outer boundary surface68and the oppositely lying “inner” boundary surface73of the support plate—of the same, so that the support plate64has a “free support segment”74projecting on one side beyond the shank66.

In a base area76immediately adjacent the support plate64the glide stone62has a threaded bore77, of which the central axis78, seen in the closed condition of the wedge lock36/r intersects the central longitudinal axis43of the clamp bolt39perpendicularly and runs in the longitudinal central plane56of the guide block48.

A threaded spindle79is in engagement with the threaded bore77which extends through each other aligned bores81/1and81/2of the transverse walls59/1and59/2of the guide block48. By rotating the threaded spindle79by means of the actuating element31in alternative directions of rotation—clockwise and counterclockwise—the glide stone62is displaceable in the opposing directions represented by the arrows82and83, wherein the glide stone62is slidably guided by means of the longitudinal guide surfaces84/1and84/2of its base area76as well as the herewith respective coplanar longitudinal guide surfaces86/1and86/2of its free end segment87between the each other oppositely running internal surfaces57/1and57/2of the longitudinal walls58/1and58/2of the guide block48. Between the base area76and the free end segment87of the clamp shank66of the glide stone63there are machined-in respectively external open “wedge”—grooves, of which the groove base respectively runs in the plane89/1or as the case may be89/2parallel to the glide guide surfaces84/1and86/1or as the case may be84/2and86/2.

The planar walls91/1and91/2of the wedge grooves88/1and88/2adjacent to the free end surfaces71of the clamp shank—end segment87join at right angles respectively to the groove base surfaces89/1and89/2and extend, seen in the configuration of the wedge lock36/r according toFIG. 2abetween the narrow inner end surface72of the clamp shank66and its narrower outer end surface67diagonally increasing in such a manner that these groove walls91/1and91/2join with the free surface71of the clamp shank66at a wedge angle α of approximately 20°, so that the free end segment87/1forms on both sides of the bar92connecting the base portion76with the free end segment87two clamp wedges93/1and93/2, by driving of which into complementary designed anchor slits or grooves94/1and94/2(FIG. 2e) of the clamp bolts39the wedge lock36/r is tensionable.

The clamp39is formed, in accordance with the detailed representation ofFIG. 2e, symmetric relative to its “longitudinal”—central plane96which contains the central longitudinal axis43of the clamp bolt39, and which in the closed condition of the wedge lock36/r coincides or overlaps with the longitudinal central plane63of the glide stone62.

The two anchor grooves94/1and94/2provided similarly in the inside of the anchoring segment46of the clamping bolt39have as a “common” inner groove wall an inner end surface97running at a right angle to the longitudinal central plane96, and extending between planar parallel to each other running groove base surfaces98/1and98/2. The separation of these groove base surfaces98/1and98/2from each other is slightly larger than the distance of the longitudinal guide surfaces84/1and84/2of the base area76of the glide stone62, so that sufficient guide play is present, in order to be able to introduce the glide stone62with its clamp wedge93/1and93/2easily into the anchor groove94/1and94/2of the clamp bolt39.

These anchor grooves94/1and94/2of the clamp bolt39are set off from each other by a transverse slit99, of which—planar—slit walls101/1and101/2have a separation from each other, which is somewhat larger than the thickness of the bar92, which connects the base segment76of the glide stone62with the free end segment87of the clamp shank66forming the wedge99/1and99/2, but is significantly smaller than the separation of the longitudinal guide surfaces86/1and86/2of the wedge forming end segment87of the clamp shank66of the glide stone62, such that a sufficiently large surface overlapping of the clamp wedge surfaces93/1and93/2with the outer groove wall surfaces102/1and102/2of the clamp bolt39results, which likewise describe with the outer end surface103of the clamp bolt93(FIG. 2f) an angle α of approximately 20°.

The wedge lock36/l shown in the left part ofFIG. 2ais constructionally the same as the wedge lock36/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 plane22. In the illustrative embodiment selected for explanation the threaded bore77of the glide stone62is in threaded engagement with a right threaded—segment104of the threaded spindle79, while the thread bore77of the glide stone62of the “right” wedge lock36/r is in threaded engagement with a left threaded—segment106of the threaded spindle79.

By the rotation of the threaded spindle79via the rotation knob39in the counterclockwise direction represented by the directional arrow107, the glide stones62of both wedge locks36/l and36/r experience therewith a displacement in the direction of the arrows83, that is, away from each other, that is, in the sense of an opening of the wedge locks36/l and36/r.

These opening displacement movement of the glide stones62are limited by stops108, which are so arranged on the outer transverse walls59/2, that in the abutment limiting end position the rear mold half13can be easily removed without difficulty from the engagement position of its clamp bolts39with the centering bores47of the guide blocks48and the somewhat wider or broader transverse bores44of the rear clamp plate16.

On the other hand, when the threaded spindle79is rotated in the clockwise sense represented by the rotation arrow109, the glide stones62of both wedge locks36/l and36/r experience a towards each other directed displacement in the direction of the arrow82, which leads to the represented clamp position, in which the “slanted” wedge surfaces91/1and91/2of the clamp wedge93/1and93/2of the glide stones62with a, through the actuating force settable surface pressing, likewise lie against the diagonal counter-surface101/1and101/2of the clamp bolts.

The wedge angle α is selected to be slightly larger than the value αsbelow which for a preselected pairing of the materials of which the clamp bolts39and the glide stones62are made, a self jamming fixing of the wedge locks36/l and36/r in the represented clamp position would be possible. In order at the same time to achieve a “self-jamming” fixing of the wedge locks36/l and36/r in the clamp position, the mutually engaging threads of the glide stones62and of the “counter-sense” threaded segments104and106are formed to be self-jamming.

By the design of the support plate64of the glide stone62with each other facing support plate projections74as well as the arrangement of the threaded spindle79between the clamp elements and the support plates64of the wedge stones, tilt movements which otherwise—during the clamping operation—could act upon the glide stones62, 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 half13, which could lead to a misalignment between this and the rear clamp plate16and/or to a misalignment between the mold halves12and13.

The purpose of a substantial avoidance of such transverse forces or diagonal forces is also served by a “floating” anchoring of the clamp bolts39on the rear mold half13, in such a manner, that the clamp bolts39in the radial direction, that is, in all conceivable directions perpendicular to the central longitudinal axis43have sufficient play for deviating in their anchoring, when the respective clamp bolt39is introduced in the fine centering bore47of the respective guide block48, wherein this centering bore47widens with a diagonal inlet chamfer111to the diameter of the transverse bore44of the rear clamp plate16which is larger by the amount δ d (FIG. 2a).

For explaining this floating anchoring now reference is made toFIGS. 3aand3b. In accordance therewith the clamp bolt39is respectively received in a cylindrical-pot shaped recess112in the rear mold half, of which the diameter is somewhat larger than the length of a basically right angled burr113, which beginning from the anchoring end of the clamp bolt39extends flange shaped at a right angle therefrom.

The pot-shaped recess112has a circular round widening114, which is set off from the recess112by a ring shoulder116. In this widening114an anchoring ring117is seated or introduced and in the area of the ring shoulder16is screwed tight to the mold half13. The anchoring ring117has an inlet opening indicated overall with reference number118and having a contour which can be seen fromFIG. 3b. This inlet opening is bordered circular round on other oppositely lying sector regions119, wherein the radius of this circular round edged opening area119is somewhat larger than the radius of the clamp bolt39. The opening sections119of circular shaped contour, the inlet opening118has substantially U-shaped recesses121, of which the middle plane122runs at a right angle to the middle plane123of the circular round edged region119. By the overall slit shaped inlet opening118the clamp bolt39can be introduced with its flange or burr113in the recess112of the rear mold half13. This introduction occurs against the return spring force of a return spring124, which is received in a central blind bore126of the clamp bolt39and basically supports itself on the base127of the recess112.

By rotating the clamp bolt about 90°, while the return spring is somewhat compressed, the flange or burr113can be brought into a position in which it can engage with mutually aligned “radial” inner groove128of the anchoring ring117and is held in this detent position by the pretensioned return spring124. The grooves128also have sufficient play, such that the floating anchoring of the clamp bolt39is 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.