Abstract:
A clamping device for an injection blow molding machine incorporates separate clamp movement actuators for joining or separating opposing mold parts and clamping actuators for applying a clamping force to closed mold parts. Opposing locking columns and locking collars are locked together and a clamping force is applied to opposing locked columns and collars. A stroke movement of the locking collars can optionally be provided to allow maximum clamp area clearance for a preform or blow-molded product entering or leaving the clamp area. The distance of stroke movement can be adjusted to accommodate molds of varying sizes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/365,924, filed Mar. 20, 2002. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to injection blow molding machines, and in particular to clamping devices that are used to apply a clamping force to mold parts used in injection blow molding machines. 
     BACKGROUND OF THE INVENTION 
     A typical thermoplastic injection blow molding machine uses a clamping device to apply a clamping force that holds the parts of a mold together while either a hot thermoplastic resin is injected into a clamped injection mold to form a preform (parison), or a gas (typically air) is injected into a preform to form a blow-molded product, such as a bottle or other container, that takes on the shape of the interior of the clamped blow mold. A mold generally comprises a two-part machined article. Adjoining faces of the mold parts, or halves, are brought together and clamped for forming the preform or product, and separated for releasing the preform or product from the mold. For the typical three-station injection blow molding machine, a core rod is used to transfer the preform from the injection station to the blow mold station, and to transfer the product from the blow mold station to the product removal station where the product is stripped from the core rod. 
     There are generally two types of clamping devices. The first is referred to as a C-frame design that has a series of hydraulic clamping cylinders mounted directly to the C-frame assembly. Clamping cylinders are mounted over the mold parts and push downward against the top of the mold parts to apply clamping force. A benefit of the C-frame design is the absence of any frame components or tie bars in the molding area (i.e., the volume between the mold parts when the clamping device is in the opened position) that could limit access to the molding area. The mold parts are clamped between the overhead cylinders and a machine table that forms a fixed platen for the lower mold half. Therefore the frame of the machine must resist the clamping forces exerted by the hydraulic clamping cylinders. However, in this arrangement, the cylinders are more readily accessed for maintenance and replacement. 
     The second type of clamping device is referred to as a tie-bar design that incorporates a pair of tie-bars and bushings connecting an upper and lower yoke assembly. The machine table is situated directly between the two yoke assemblies. Hydraulic cylinders are mounted under the machine table between the table and the lower yoke assembly. As the actuators on the hydraulic cylinders extend, the upper yoke assembly is pulled downward toward the table, and the mold parts are clamped between the machine table and upper yoke assembly. For this design, the structural frame of the machine does not have to resist the clamping forces. However, as the blow-molded product increases in diameter, the height of the joined blow mold halves increases. Consequently, the length of tie bars and mold strokes require that the table height be increased, since the lower yokes must move the same distance as the upper yokes. The height requirement of the table can become so great that a raised structural platform must be provided for an operator to operate the machine. Hydraulic cylinders are located beneath the table. Further maintenance or replacement of the hydraulic cylinders is difficult due to the location of the cylinders. 
     Therefore, there is the need for an improved clamping device that will provide unrestricted access to the molding area of the machine and allow better arrangement of machine components. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, the present invention is an apparatus for and method of clamping a multi-part mold used in an injection blow molding machine and process wherein two or more locking columns are commonly mounted with a first mold part, and two or more locking collars are commonly mounted with a second opposing mold part. To clamp the mold parts, the first mold part, and two or more locking columns, are moved towards the second opposing mold part and two or more locking collars so that the opposing facing surfaces of the mold parts meet, and the columns lock into the collars. After locking, clamping force is applied to the mold parts by the interlocked column and collar elements. Columns and collars may be arranged to provide a maximum clearance distance between the mold parts in the opened position. The means for bringing the first and second mold parts together and separating them is separate from the clamping means. 
     In another aspect, the present invention is an apparatus for and method of injection blow molding wherein at least the injection mold parts or the blow mold parts are clamped together by joining two or more locking columns, commonly mounted with a first mold part, with two or more locking collars, commonly mounted with a second mold part. After joining opposing surfaces of the first and second mold parts and locking opposing two or more locking columns and collars, clamping force is applied to the mold parts by the interlocked column and collar elements. The means for bringing the first and second mold parts together and separating them is separate from the clamping means. 
     In another aspect, the present invention is an apparatus for and method of injection blow molding wherein the injection mold parts and the blow mold parts are clamped together by joining at least three locking columns, commonly mounted with a first injection and blow mold parts to an A-shaped upper yoke, with at least three locking collars, commonly mounted with a second injection and blow mold parts to a fixed platen. After joining opposing surfaces of the first and second injection and blow mold parts and locking opposing two or more locking columns and collars, clamping force is applied to the injection and blow mold parts by the interlocked column and collar elements. The means for bringing the first and second injection and blow mold parts together and separating them is separate from the clamping means. 
     Other aspects of the invention are set forth in this specification and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown. 
     FIG.  1 ( a ) is one example of an injection blow molding machine of the present invention with the enclosure around the plastifier equipment removed. 
     FIG.  1 ( b ) is the injection blow molding machine shown in FIG.  1 ( a ) with enclosures around the base and multi-station assembly removed. 
     FIG.  2 ( a ) is a first perspective view of a multi-station assembly utilizing one example of the clamping device of the present invention. 
     FIG.  2 ( b ) is another perspective view of the multi-station assembly shown in FIG.  2 ( a ). 
     FIG.  2 ( c ) is another perspective view of the multi-station assembly shown in FIG.  2 ( a ). 
     FIG. 3 illustrates one example of a clamping device of the present invention in the opened position. 
     FIG. 4 illustrates another example of a clamping device of the present invention for an injection blow molding machine in the opened position. 
     FIG. 5 illustrates the clamping device shown in FIG. 4 in the closed position. 
     FIG. 6 illustrates another example of a clamping device of the present invention in the opened position in which a pivot arm is used to raise and lower locking collars for mating with a locking column. 
     FIG. 7 illustrates the clamping device shown in FIG. 6 in the closed position. 
     FIG. 8 is a cross sectional view of one example of a clamping actuator for use with a clamping device of the present invention. 
     FIG. 9 illustrates a top plan view of one example of a locking collar used with one example of the clamping device of the present invention. 
     FIG. 10 illustrates selected components of the actuators for opening and closing adjoining mold parts, and for clamping mold parts together for the multi-station assembly shown in FIGS.  2 ( a ),  2 ( b ) and  2 ( c ). 
     FIG. 11 illustrates one example of upper and lower yokes that can be used with the multi-station assembly shown in FIGS.  2 ( a ),  2 ( b ) and  2 ( c ). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, wherein like numerals indicate like elements there is shown in FIG.  1 ( a ) and FIG.  1 ( b ) one example of injection blow molding machine  50  of the present invention. In operation, raw material, such as pellets composed of a plastic polymer resin, are supplied via hopper  60  to the feed section end of a plastifier, which in this example is a reciprocating screw within screw housing  62 . The screw can be driven by a suitable power source, such as a hydraulic or an electrical motor  56 . The output shaft of the drive motor is connected to the reciprocating screw via a spline through one or more interconnecting drive components, such as a thrust bearing, within drive housing  58 . The interconnecting drive components terminate at the feed end of the screw. The resin stock proceeds from the feed section of the screw to a compression section in which the softened pellets are compressed and melted into a resin melt. A final metering section of the screw homogenizes the melt and pumps it out of nozzle  64  into a clamped injection mold installed in the injection station as further described below. 
     FIGS.  2 ( a ),  2 ( b ) and  2 ( c ) illustrate one example of an injection blow molding machine multi-station assembly of the present invention. Multi-station assembly  66  comprises injection mold station  68 , blow mold station  72  and extraction (ejection) station  70 . The injection station, blow mold station and ejection station are generally disposed in a triangular relationship around a transfer head (rotary indexing) table  74 . One or more core rods, typically illustrated by core rod  74   a  in FIG.  2 ( b ), are attached to each side of the rotary indexing table. Rotary indexing table  74  is rotationally driven, for example, by a motor drive having its output shaft attached to centered opening  74   b  in the rotary indexing table. In this arrangement core rods on any one of the three sides of the table are sequentially indexed by the rotary indexing table&#39;s drive between adjacent stations. In injection mold station  68 , opposing surfaces of the upper and lower injection mold halves are joined together and clamped around at least one core rod, and the molten resin is injected from nozzle  64  into the void between the female portion of the clamped injection mold and the one or more male core rods to form a resin preform around the core rod. If multiple core rods are accommodated by the injection mold, then a manifold is used to distribute the molten resin from the nozzle to the core rods. After the injection mold halves are unclamped and opened, the rotary indexing table rotates the core rods with molten resin adhering to them approximately 120 degrees to blow mold station  70 . In the blow mold station, upper and lower blow mold halves are closed and clamped between the core rods with the preforms on them. Air is blown through the core rods to push the outer surfaces of the preforms against the interior mold walls to shape the blow-molded product while the preform neck retains the shape formed by the preform. After the blow mold halves are unclamped and opened, the rotary indexing table&#39;s drive rotates the core rods with the necks of the blow-molded products adhering to them approximately 120 degrees to ejection station  72  wherein an ejector mechanism (not shown in the drawings) ejects the blow-molded product from the core rods. After ejection of the product, these core rods are indexed to injection mold station  68 , and the injection blow molding process is repeated. Therefore when triangular rotary indexing table  74  is stopped in an indexed position, and the injection and blow molds are clamped, an equal number of preforms, or product, on core rods on each side of the table are being processed or ejected in each of the three stations. 
     Referring now to FIG. 3 there is shown one example of the clamping device of the present invention that can be used in an injection mold station and/or a blow mold station. Clamping device  10  is shown in the opened position in FIG.  3 . Mold halves or parts,  16  and  18 , are situated between upper yoke assembly  12  and fixed platen, or machine table  14 . Fixed platen or machine table  14  may also be other fixed structure attached to the machine table, such as a lower yoke assembly. Mold part  16  is attached directly or indirectly to the upper yoke assembly, and mold part  18  is attached directly or indirectly to the machine table. For example a mold die set and/or a spacer may be connected between the upper yoke and mold part  16 , and/or the fixed platen and mold part  18  as illustrated below in other typical examples of the invention. Locking columns  20  are suitably attached to the upper yoke assembly and extend downward on either side of mold part  16 . In this example of the invention, each locking column comprises main column  20   a  and locking cam  20   b , which is attached to the main column by neck  20   c . Locking collars  24  are suitably attached to machine table  14  and extend upward on either side of mold part  18 . FIG. 9 is a top plan view of locking collar  24  showing collar tabs  24   a  in a recess of the locking collar that lock around neck  20   c  of cam  20   b , as further described below. In this example of the invention, the end surface  20   d  of each locking column extends below facing surface  16   a  of upper mold part  16 . Each locking column is axially aligned with an opposing locking collar. A pair of clamp movement actuators, open and close the clamping device by moving upper yoke assembly  12 , with attached upper mold part  16  and locking columns  20 , away from, or towards, fixed lower mold part  18  and the machine table. In this example of the invention, the clamp (opening and closing) movement actuators are hydraulic cylinders  30  with piston (output) rods  30   a  optionally housed in bushings to also serve as guide posts. The end of each output rod or shaft is suitably attached to upper yoke  12  so that when closing, piston rod  30   a  moves vertically downward into hydraulic cylinder  30 , and when opening, the piston rod moves vertically upward out of the cylinder. Since the opening and closing actuators are not used to apply clamping forces, they can be positioned at an appreciable distance from the mold parts, for example, near the opposing ends of upper yoke  12 , to avoid impeding access to the clamping area by preforms or blow-molded product. In the present invention, clamping force is obtained by securing (locking) opposing locking collars  24  and locking columns  20  together and applying a clamping force to the locked collars and columns as further described below. 
     In the transition of clamping device  10  from the opened to closed position, clamp movement hydraulic cylinders  30  move upper mold part  16  downward towards lower mold part  18  until opposing facing surfaces of the upper and lower mold parts are joined together but not clamped under pressure. At the same time, since the locking columns protrude below the facing surface of mold part  16 , the end of each locking column, in this example of the invention, cam  20   b , protrudes into the recess in the upper end of collar  24 . In the closed position, the cams of the pair of locking columns are seated in the recesses of the respective opposing locking collar. 
     FIG. 8 is a cross sectional view of a locking collar with associated clamping actuator  26  and rotation actuator  28  that is used in one example of the invention. In this non-limiting example of the invention, clamping actuator  26  is a linear hydraulic cylinder and rotation actuator  28  is a rotary hydraulic motor. Locking pin  42  retains locking collar  24  to one end of piston rod  40 . In this non-limiting example of the invention, locking collar  24  is attached by screw thread to the end of rod  40 . Collar  24  is attached to clamping actuator  26  via piston rod  40 , which is attached to clamping piston  44 . Sliding spline  50  is attached to clamping piston  44  and is rotatably controlled by the rotation actuator, which may be a hydraulic rotary motor. Spline  50 , piston  44  and rod  40  are arranged so that rotation of spline  50  by the rotation actuator results in the rotation of collar  24 . 
     After the cams are seated in the recesses of the collars, each collar is rotated to a locked position by supplying hydraulic fluid to hydraulic rotation actuator  28  via conduit  51 . Collar tabs  24   a  lock around the neck  20   c  of each column to lock and hold the opposing locking columns and locking collars together. 
     In other examples of the invention, the rotation actuator may comprise a chain drive wherein one or more hydraulic rotation actuators  28  are replaced by a horizontally oriented sprocket that engages a chain driven by a suitable drive motor. In this arrangement one motor drive could be used to rotationally drive all locking collars used in a particular configuration. 
     Clamping force is then applied to the clamped mold parts by supplying hydraulic fluid to upper clamping piston chamber  46  via conduit  47  to apply pressure against the upper head of piston  44 . With the columns locked in collars  24 , the two mold parts are held together at the applied clamping force. If the clamped mold parts are an injection mold, then molten resin is injected into the mold. If the clamped mold parts are a blow mold, then air is blown into the preform to form the blow-molded product in the blow mold. 
     Applying the clamping force with a mold clamping means separate from the means for opening and closing the mold parts allows the opening and closing actuators to accomplish faster opening and closing of the mold parts since the opening and closing actuators are sized only for opening and closing, and not for clamping force requirements. The clamping force required to prevent injection mold parts from opening during injection of molten resin into the mold can approach 200 tons, which requires a relatively massive actuator that would be relatively slow acting as an opening and closing actuator. Further large actuators would block access to the molding area. 
     Once the molding step is completed (that is, forming a preform or blow-molded product), hydraulic fluid in upper piston chamber  46  is released through conduit  51  to decompress the clamping actuator. Each collar is then rotated to an unlocked position by supplying hydraulic fluid to rotation actuator  28  via conduit  53  to rotate the collar in a direction counter to the rotational direction for locking a collar to a column. Clamp movement hydraulic cylinders  30  then move mold part  16  upwards to the clamp opened position so that the preform or blow-molded product can be removed. In this particular example of the invention, since the locking collars are not raised or lowered, clamping actuator  26  may be a single chamber hydraulic cylinder without lower piston chamber  48 . 
     FIG. 4 illustrates another example of the clamping device of the present invention that can be used in an injection mold station and/or a blow mold station. End surface  20   d  of each locking column, and more specifically in this particular example of the invention, the end surface of each locking cam  20   b , is substantially flush with or above the facing surface  16   a  of upper mold part  16 , and the end surface  24   c  of each locking collar  24  is substantially flush with or below the opposing facing surface  18   a  of lower mold part  18 . In the transition of clamping device shown in FIG. 4 from the opened to the closed position, as shown in FIG. 5, after the opposing faces of mold parts  16  and  18  make contact, hydraulic fluid is supplied to lower piston chamber  48  via conduit  49  to raise collar  24  so that cam  20   b  sits in the recess of the collar. In other examples of the invention, the collar may be raised at the same time that the upper mold part  16  is being lowered. The collar is then rotated as in the previous examples of the invention to lock the mold parts together. Clamping pressure is applied as in the previous examples. The advantage of the present example over the example of the invention shown in FIG. 3 is that in the opened position, the entire distance, d 2 , between the upper and lower opposing faces of the mold parts is available for access by preforms or finished blow-molded products on core rods to the mold clamping area. A further advantage of the present example of the invention is that it can conveniently accommodate multiple mold parts with different vertical lengths (heights) by changing the collar raise stroke distance (that is, the height that the locking collar raising and lowering actuator raises the collar) to recess cam  20   b  into the collar. In this particular example of the invention, actuator  26  also serves as the locking collar raise and lower actuator. Supplying hydraulic fluid to lower piston chamber  48  via conduit  49  will raise the locking collar to the required height. After locking rotating of the collar, lower piston chamber  48  can be depressurized by release of hydraulic fluid via conduit  49  and upper piston chamber  46  can be pressurized as described above to apply the clamping force. Further a two-directional hydraulic clamping actuator  26  as shown in FIG. 8 is only required for examples of the invention wherein the locking collar must be raised for mating with its opposing locking column. When the locking collar is not raised for mating with its opposing locking column, a single-directional hydraulic clamping actuator is required to apply a clamping force. After a blow molding process is completed in a clamped mold, clamping pressure can be removed by depressurizing the single-directional hydraulic clamping actuator. 
     FIG.  6  and FIG. 7 illustrate another example of the invention wherein locking collar  24  is raised and lowered by the pivot action of pivot arm or member  80  about pivot point  82 , as typically illustrated in the figures, so that when clamp movement actuator  30  brings upper mold part  16  adjacent to lower mold part  18  the pivot action raises the locking collar to the appropriate height for mating with the opposing locking column. Consequently in this arrangement with locking collar raising and lowering, only a single-directional hydraulic clamping actuator is required. 
     In another example of the invention, locking collars  24  can be located in place of locking columns  20  in FIG. 3 or FIG. 4, and locking columns  20  can be located in place of locking collars  24  in the same figures. That is, the locking collars may be associated with upper yoke  12  and located adjacent to upper mold part  16 , and the locking columns may be associated with the machine table, or fixed platen  14 , and adjacent to lower mold part  18 . In this arrangement physically separated rotation actuators and clamping actuators are provided since the rotation actuators would be situated on top of the upper yoke, with each rotation actuator in axial alignment with a locking collar, so that the rotation actuator could rotate the collar after the end of an opposing locking column is inserted into it, to lock and unlock the columns and collars together. Generally, because of its size and weight, the clamping actuators would remain beneath the fixed table, with each of the clamping actuators in axial alignment with a locking column, to apply a clamping force when the locking columns and locking collars are locked together. Further if raising and lowering locking collars are used in this example of the invention, a separate means for raising and lowering the locking collars, now associated with the upper yoke, may be provided as illustrated in FIG. 6, for example, except that the pivot arm is connected at its opposing ends to the clamp movement actuator and the locking collar, now associated with the upper yoke to achieve lowering of the locking collars when the clamp movement actuator brings the upper and lower mold parts together, and raising of the locking collars when the clamp movement actuator separates the upper and lower mold parts. In general, for all examples, of the invention, the clamping force may be applied either to the locking collar or locking column when the column and collar are locked together. 
     Returning now to the first example of the invention, in FIGS.  2 ( a ),  2 ( b ) and  2 ( c ), upper yoke  12   a  is an A-shaped structure that forms a single upper yoke for the clamping devices used in injection station  68  and blow mold station  70 . The injection station and blow mold station are each situated under one of the two legs of the A-shaped structure. The center member of the A-shaped structure connecting the two legs together is an optional structural support member. In this non-limiting example of the invention, by utilizing the A-shaped upper yoke structure, one of four separate pairs of clamp movement actuators and clamping actuators are eliminated since one pair situated near the joined end of the two legs serves both the injection and blow mold stations as further described below. 
     Injection mold die set comprises upper injection mold die plate  15   a  and lower injection mold die plate  17   a , and provides a means for attaching the upper and lower injection mold halves (not shown), respectively, to upper yoke  12   a  and machine table  14 . In this non-limiting example of the invention, optional spacer  13   a  serves as an intervening connecting element between the upper yoke and the upper injection mold part. The advantage of spacer  13   a  is that interchangeable spacers having different heights can be used to accommodate mold parts with different heights. The upper and lower injection mold parts are suitably attached to the opposing surfaces of the upper and lower injection mold dies, respectively. Piston rods  30   a  housed in bushings serve as guide posts to assure vertical alignment between paired upper and lower molding surfaces (and attached mold parts) as the mold parts move between opened and closed positions. 
     In a similar arrangement for blow mold station  70 , upper blow mold die plate  15   b  and lower blow mold die plate  17   b , provide a means for attaching the upper and lower blow mold halves (not shown), respectively, to upper yoke  12   a  and machine table  14 . In this non-limiting example of the invention, optional spacer  13   b  may also be used as an intervening connecting element between the upper yoke and the upper blow mold part. The upper and lower blow mold parts are suitably attached to the opposing surfaces of the upper and lower blow mold dies, respectively. 
     As previously mentioned, with use of the A-shaped structure for upper yoke  12   a  in this example of the invention, three each of clamp movement actuators, locking columns, locking collars and clamp actuators are required for both the injection mold station and the blow mold station. These elements are most clearly illustrated in FIG. 10 with selected components of the multi-station assembly not shown. Also in FIG. 10, locking collar  24  is not shown attached to the threaded end of piston rod  40  at which opening  42   a  is provided for insertion of locking pin  42 . Section  20   a  ′ of each locking column passes through an opening in upper yoke  12   a  and is secured to the upper yoke by suitable fastener  20   e . Section  30   a  ′ of each piston rod  30   a  of hydraulic cylinder  30  passes through an opening in upper yoke  12   a  and is secured to the upper yoke by suitable fastener  30   c.    
     The operation of the clamp movement actuators, locking columns, locking collars and associated actuators for the example of the invention shown in FIGS.  2 ( a ),  2 ( b ) and  2 ( c ) and FIG. 10 are similar to the operation of these components in other examples of the invention. 
     FIG. 11 illustrates A-shaped upper yoke  12   a  and optional lower yoke  12   b  that can be used to secure clamping and rotation actuators  26  and  28 , respectively, in place below machine table  14 . The top of lower yoke  12   b  is attached to the bottom of machine table  14 . Attachment plate  26   a  for each clamping and rotation actuators is attached to the bottom of lower yoke  12   b . As noted above, clamping forces for an injection mold can be on the order of 200 tons, which requires the use of large hydraulic clamping cylinders that can weight several hundred pounds. Clamping actuator replacements are necessary over the service life of an injection blow molding machine. Providing notched openings  12   c  in lower yoke  12   b  facilitates removal of an installed clamping actuator by allowing the actuator to be tilted for removal, once the adjacent relatively small and lightweight clamp movement hydraulic cylinder  30  is removed. Otherwise the clamping and rotation actuator would need to be dropped vertically down for its entire length to clear the level of machine table  14 , which would requiring raising of the height of the machine table. In some arrangements, the increased height can be significant and make access to multi-station assembly  66  above the machine table difficult. 
     Typically clamping pressure for a preform mold is much greater than that for a blow mold. For example, a ratio of 6:1 is typical between preform mold clamping pressure and blow mold clamping pressure. With the A-shaped arrangement of the upper yoke, the clamping cylinder at the joined end of the two legs must apply clamping force for both the injection mold and the blow mold while the other two cylinders apply only the clamping force for the injection mold or the blow mold. The control system for hydraulic fluid to the three clamping cylinders incorporates a feedback system to ensure that an equalized clamping pressure is applied across both the preform mold and the blow mold. 
     In other examples of the invention, respective locations of the locking columns and locking collars may be reversed so that the columns, rather than the collars, are associated with the clamping and rotation actuators, and, for the example of the invention shown in FIG.  4  and FIG. 5, the columns, rather than the collars, are raised and lowered. Further other suitable column and collar locking elements are contemplated as being within the scope of the invention as long as they a means for holding the two mold parts together for application of clamping pressure between the mold parts. While hydraulic means are used for mold opening and closing, holding and clamping functions, other drive means, such as an electric drive, may be used for one or more of these functions. While the mold in the example comprises two parts and, in some examples of the invention, two clamp movement actuators, locking columns and locking collars are used, other multiple combinations of mold parts and/or clamp movement actuators, locking columns and locking collars may be used in the present invention. 
     Although the above examples illustrate the clamping device of the present invention with an injection blow mold machine having three stations, the invention can be applied to injection blow molding machines with any number of stations, and the clamping device of the present invention may be other than horizontally oriented as shown in the above examples of the invention. Further while the above examples illustrate the clamping device of the present invention with an injection blow molding machine, the invention can be applied to other types of injection molding machines, such as, but not limited to, injection stretch blow molding machines. 
     The foregoing examples do not limit the scope of the disclosed invention. The scope of the disclosed invention is further set forth in the appended claims.