Patent Publication Number: US-10773440-B2

Title: Extrusion die having adjustable end seal system and method of use

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 14/658,658, filed Mar. 16, 2015, and published as U.S. Patent App. Pub. No. 2016/0271853 on Sep. 22, 2016, the disclosure of which is hereby incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to extrusion dies. More specifically, this invention relates to the end seals of an extrusion die. 
     BACKGROUND OF THE INVENTION 
     Extrusion dies are widely used for extruding sheets of polymer. These dies have an internal flow passageway through which polymer flows on its way to an outlet orifice. The extrudate leaves the die through the outlet orifice. Two end seals are provided to close the lateral sides of the internal flow passageway. Typically, each end seal is sandwiched between an end of the die and an end plate secured thereto. In the past, some end seals have been tightened against the end of the die by individually advancing each of a series of threaded screws. The leading ends of the screws then push the end seal more firmly against the end of the die. 
     This approach has some drawbacks and limitations. For example, to firmly clamp such an end seal against the end of a die, it is necessary to separately manipulate each of a series of different screws. Moreover, getting all the screws tightened to the same degree requires a certain amount of time, effort, and/or expertise. 
     It would be desirable to provide an end seal adjustment system that can simultaneously apply substantially uniform pressure to multiple points about the area of an end seal. It would also be desirable to provide an end seal adjustment system that provides single point adjustment of the entire area of an end seal. Further, it would be desirable to provide an end seal adjustment system that can be installed on, and removed from, an extrusion die quickly and easily. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an adjustable end seal assembly in accordance with one embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of the adjustable end seal assembly of  FIG. 1 , with the assembly shown from a different perspective than in  FIG. 1 . 
         FIG. 3  is a side view of the adjustable end seal assembly of  FIG. 1 , with the assembly shown, in isolation, in an assembled state. 
         FIG. 4  is a cross sectional view of the adjustable end seal assembly of  FIG. 3 , with the cross section taken along lines A-A of  FIG. 3 . 
         FIG. 5  is a perspective view of the adjustable end seal assembly of  FIG. 1 , with the assembly shown, in isolation, in an assembled state. 
         FIG. 6  is a broken-away, front perspective view of an extrusion die equipped with the adjustable end seal assembly of  FIG. 1 . 
         FIG. 7  is a perspective view of the end plate and adjustable end seal assembly of  FIG. 6 , showing a die-facing side of the end plate and adjustable end seal assembly. 
         FIG. 8  is a front perspective view of an extrusion die and two adjustable end seal assemblies in accordance with another embodiment of the invention, with one of the adjustable end seal assemblies shown exploded from the die. 
         FIG. 9  is a front perspective view of the extrusion die and adjustable end seal assemblies of  FIG. 8 , with both adjustable end seal assemblies mounted operatively on the extrusion die. 
         FIG. 10  is a partially exploded rear perspective view of the extrusion die and adjustable end seal assemblies of  FIG. 9 . 
         FIG. 11  is a partially exploded front perspective view of the extrusion die and adjustable end seal assemblies of  FIG. 9 . 
         FIG. 12  is a cross-sectional detail view of the extrusion die and one of the adjustable end seal assemblies of  FIG. 9 , with that adjustable end seal assembly shown in an engaged configuration. 
         FIG. 13  is a cross-sectional view of the extrusion die and the other adjustable end seal assembly of  FIG. 9 , with that adjustable end seal assembly shown in a disengaged configuration. 
         FIG. 14  is a rear perspective view of the extrusion die and adjustable end seal assemblies of  FIG. 9 , with a gasket of one of the adjustable end seal assemblies shown exploded from the die. 
         FIG. 15  is a front perspective view of an extrusion die and two adjustable end seal assemblies in accordance with still another embodiment of the invention. 
         FIG. 16  is an exploded, broken-way, front perspective detail view of the extrusion die and one of the adjustable end seal assemblies of  FIG. 15 . 
         FIG. 17  is another exploded, broken-way, front perspective detail view of the extrusion die and one of the adjustable end seal assemblies of  FIG. 15 . 
         FIG. 18  is still another exploded, broken-way, front perspective detail view of the extrusion die and one of the adjustable end seal assemblies of  FIG. 15 . 
     
    
    
     SUMMARY OF THE INVENTION 
     In one embodiment, the invention provides an extrusion die having a die body, an internal flow passageway, an outlet orifice, an adjustable end seal assembly, and an end plate. The die body has an end region to which the end plate is mounted. The die body includes two halves between which the internal flow passageway extends. The internal flow passageway leads to the outlet orifice. The adjustable end seal assembly includes an end seal device and a wedge mechanism. The end seal device closes one side of the internal flow passageway such that, when the extrusion die is operated, extrudate flows through the internal flow passageway and alongside the end seal device. The adjustable end seal assembly has an engaged configuration and a disengaged configuration. When the adjustable end seal assembly is in the engaged configuration, the end seal device is held forcibly against the end region of the die body. When the adjustable end seal assembly is in the disengaged configuration, the end seal device is either spaced apart from the end region of the die body or held against the end region of the die body with less force than when in the engaged configuration. 
     Another embodiment of the invention provides a method of operating an extrusion die having a die body with an end region, an internal flow passageway, and an adjustable end seal assembly having an end seal device and a single actuator. The method involves moving the adjustable end seal assembly from a disengaged configuration to an engaged configuration by operating the single actuator of the adjustable end seal assembly. When the adjustable end seal assembly is in the engaged configuration, the end seal device is held forcibly against an end region of the die body. When the adjustable end seal assembly is in the disengaged configuration, the end seal device is either spaced apart from the end region of the die body or held against the end region of the die body with less force than when in the engaged configuration. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following detailed description is to be read with reference to the drawings, in which like elements in different drawings have like reference numerals. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. Skilled artisans will recognize that the examples given have many useful alternatives, which fall within the scope of the invention. 
     The invention provides an adjustable end seal assembly for extrusion dies. The following disclosure begins by describing the adjustable end seal assembly itself, then describes an extrusion die equipped with the adjustable end seal assembly, and finally describes methods of using such an extrusion die. 
       FIGS. 1-5  show an embodiment of the adjustable end seal assembly  10 . The assembly  10  includes a wedge mechanism  40  and an end seal device  50 . The adjustable end seal assembly  10  is movable between an expanded profile and a contracted profile. When the illustrated assembly  10  is in its expanded profile, the wedge mechanism  40  and the end seal device  50  have a greater combined thickness  90  (see  FIG. 4 ) than when the assembly is in its contracted profile. This can be appreciated by comparing  FIG. 12 , which shows the expanded profile of an end seal assembly  10 , with  FIG. 13 , which shows the contracted profile of an end seal assembly. The thickness  90  preferably increases by at least 0.050 inch, such as 0.075 inch or more, in going from disengaged configuration to the engaged configuration. Thus, when the assembly  10  is in its expanded profile, the end seal device  50  is adapted to bear forcibly against an end region of an extrusion die so as to seal one lateral side of the die&#39;s internal flow passageway. 
     The adjustable end seal assembly has an actuator that is operable to move the assembly between its expanded profile and its contracted profile. The actuator preferably is a single-point actuator that enables an operator to move the assembly  10  between its fully expanded profile and its fully contracted profile by operating only a single actuator. In such cases, the assembly  10  moves between its expanded and contracted profiles in response to operation of a single actuator. In addition, the actuator preferably is constructed such that a person can operate it without having to disassemble any part of the adjustable end seal assembly  10 . 
     In the illustrated embodiments, the actuator  20  is a rotatable actuator. When this actuator is rotated in one direction (e.g., clockwise), the adjustable end seal assembly  10  moves to its expanded profile. When this actuator is rotated in the opposite direction (e.g., counterclockwise), the adjustable end seal assembly  10  moves to its contracted profile. It is to be appreciated, however, that the actuator  20  is not required to be rotatable. For example, the actuator  20  can alternatively be a slide member that simply moves in a linear fashion, or a threaded rod that simultaneously rotates and moves axially. Other useful actuators will be apparent to skilled artisans given the present teaching as a guide. 
     In  FIGS. 1-5 , the actuator  20  is operably coupled with an elongated, axially moveable adjustment rod  30 . In this embodiment, the actuator  20  can be operated to move the adjustment rod  30  axially in first and second directions. The illustrated actuator  20  comprises a rotatable body that, when rotated in one direction (e.g., clockwise), causes the adjustment rod to move axially in the first direction, and when rotated in another direction (e.g., counterclockwise), causes the adjustment rod to move axially in the second direction. In  FIG. 4 , the first direction is to the right, and the second direction is to the left. 
     In the embodiments illustrated, the actuator  20  comprises a rotatable body threadingly coupled with the elongated adjustment rod  30 . Referring to  FIG. 4 , the rotatable body is internally threaded, and the adjustment rod  30  is externally threaded. In the embodiment of  FIGS. 1-5 , the adjustment rod  30  has a polygonal portion  34 , which is shown having a square cross section. This is perhaps best seen in  FIGS. 1, 2, and 5 . The polygonal portion  34  is provided to prevent rotation of the adjustment rod. In  FIGS. 1-5 , the adjustable end seal assembly  10  includes a guide (or “sleeve”)  35  in which the adjustment rod  30  is received. The fit between the adjustment rod  30  and the guide  35  is such that the adjustment rod is allowed to move axially but is prevented from rotating about its axis. While the guide  35  is advantageous in some embodiments, it is not required. Instead, other means can be provided for preventing rotation of the adjustment rod  30 . For example, a key projecting from the side of the adjustment rod can be received in an elongated recess track that is parallel to the axis of the rod. Other useful anti-rotation structures will be apparent to skilled artisans given the present teaching as a guide. 
     Thus, in the embodiment of  FIGS. 1-5 , by rotating the illustrated actuator  20 , the adjustment rod  30  is forced to move axially. This happens by virtue of the threaded engagement between the rotating internally threaded actuator  20  and the non-rotating adjustment rod  30 . In other embodiments, however, the rotatable actuator is omitted in favor of having an axially movable actuator, which may be an adjustment rod. In such embodiments, the adjustment rod may be prevented from rotating about its axis (e.g., it may simply move linearly) or it may simultaneously rotate and move axially. 
     In the embodiments illustrated, the adjustment rod  30  is operably coupled with a drive member  46  of the wedge mechanism  40 . In response to axial movement of the adjustment rod  30  in a first direction, the drive member  46  moves in the same direction (i.e., in the first direction). In response to axial movement of the adjustment rod  30  in a second direction, the drive member  46  moves axially in the same direction (i.e., in the second direction). As shown in  FIG. 4 , the adjustment rod  30  is attached directly to the drive member  46  of the wedge mechanism  40 . In this embodiment, a front end region of the adjustment rod  30  is attached (by a threaded attachment) to a rear end region of the drive member  46 . The adjustment rod and the drive member are thus adapted to move together as a unit. 
     If so desired, the adjustment rod can be attached indirectly (e.g., via one or more intermediate components) to the drive member. Alternatively, the adjustment rod can be an integral extension of the drive member. 
     In operation, axial movement of the adjustment rod  30  forces the drive member  46  to move in the same direction as the adjustment rod. In addition to the drive member  46 , the illustrated wedge mechanism  40  includes a side member  48  and a plurality of cam members  45 . When provided, the cam members  45  are located between the drive member  46  and the side member  48 . In the embodiments illustrated, either the drive member  46  or the side member  48  has a series of wedge surfaces  99 , which cam with (and/or roll over) respective cam members  45  during relative movement of the drive member  46  and the side member  48 . Due to the inclined (or “ramped”) configuration of each wedge surface  99 , the resulting camming and/or rolling action moves the end seal device  50  between retracted and extended positions. Thus, the end seal device  50  has a retracted position (shown in  FIG. 13 ) and an extended position (shown in  FIG. 12 ). 
     In the embodiments illustrated, either the drive member  46  or the side member  48  has a series of spaced apart grooves  405 . This is perhaps best shown in  FIGS. 1 and 4 . Each of these grooves  405  has a first end and a second end. The second end of each groove  405  is deeper than the first end, and the wedge surfaces  99  are at the bottoms of the grooves  405 . In more detail, each illustrated groove  405  is relatively shallow at one end and relatively deep at the other end, such that an inclined surface defining the bottom of each groove  405  forms the wedge surface  99 . In embodiments of this nature, the cam members  45  can advantageously be spheres received in respective grooves  405 . Thus, the illustrated cam members  45  each comprise a sphere, such as a ball bearing, that is received in one of the grooves  405 . As shown in  FIG. 4 , the bottom surface of each illustrated groove  405  defines an elongated, inclined track that rides on a sphere received in that groove during relative movement of the drive member  46  and the side member  48 . 
     Thus, in the embodiment of  FIGS. 1-5 , when the drive member  46  moves in the first direction relative to the side member  48 , the spheres start-out in the deep ends of the grooves  405  and end-up in the shallow ends of the grooves. During this movement, the wedge surfaces  99  cam with (and/or roll over) the respective spheres. This camming action moves the end seal device  50  to its extended position (see  FIG. 12 ). On the other hand, when the drive member  46  moves in the second direction relative to the side member  48 , the spheres start-out in the shallow ends of the grooves  405  and end-up in the deep ends of the grooves. This moves the end seal device  50  to its retracted position (see  FIG. 13 ). 
     If so desired, each groove  405  can have a depth change of at least 0.005 inch over a 1 inch length. The depth change per inch of groove length can optionally be, for example, about 0.008. Thus, for a groove length of 1.25 inches, the groove depth change over that length may be 0.01 inch. It is to be appreciated that these details are by no means limiting. Rather, the depth change can be varied to accommodate different applications. 
     The adjustment rod can alternatively be provided as an externally threaded bolt. For example, an externally threaded bolt can be attached to the drive member such that the bolt is free to rotate about its axis relative to the drive member, while a non-rotatable internally threaded member is threadingly coupled to the bolt. In such cases, rotating the externally threaded bolt causes the above-noted wedging action, forcing the drive member  46  to move relative to the side member  48 , hence causing the wedge surfaces  99  to cam with, and/or roll over, the cam members. Due to the inclined configuration of the wedge surfaces, this results in the end seal device  50  moving between its retracted and extended positions. 
     In the embodiment of  FIGS. 1-5 , the wedge surfaces  99  are on the drive member  46 . As noted above, however, this is not required. For example, the wedge surfaces can alternatively be on the side member. Thus, depending on whether the wedge surfaces  99  are on the drive member  46  or on the side member  48 , the wedge surfaces may move relative to the cam members  45 , or the cam members may move relative to the wedge surfaces. 
     In the embodiments illustrated, the wedge mechanism  40  includes the drive member  46 , the side member  48 , and a plurality of camming members  45 . The camming members  45  are shown as spheres (e.g., ball bearings). As an alternative, the camming members can be cylinders (e.g., pins) against which wedge surfaces of the drive member or side member cam (and/or roll) during relative movement of the drive member and the side member. In other embodiments, the camming members are omitted, and the camming action is simply provided by oppositely tapered wedge surfaces on the drive member and the side member. 
     In the embodiment of  FIGS. 1-5 , the wedge mechanism  40  includes a drive member  46  and a side member  48 , while the end seal device  50  includes an end seal plate  56  and a gasket  58 . In this embodiment, the drive member  46  is located between the side member  48  and the end seal plate  56 . In other embodiments, the end seal plate  56  itself can also serve as the side member. This is the case in the embodiment of  FIGS. 8-14 , and in the embodiment of  FIGS. 15-18 . 
     The end seal plate  56  preferably is a rigid (e.g., metal) plate, beam, or block. It may be formed of steel, such as P20 tool steel. The gasket  58  preferably is formed of a high temperature gasket material, such as PTFE with barium sulfate filler (which is sold under the trade mark Gylon), stainless steel, or aluminum. The selection of a particular gasket material will depend upon the configuration of the die to be used, the intended processes, etc. 
     In the embodiments of  FIGS. 1-5 , the adjustable end seal assembly  10  can be inserted into, and removed from, its mount on an extrusion die  100  as a single, integral unit. The same is true of the embodiment shown in  FIGS. 8-14 . This is perhaps best appreciated by referring to  FIG. 8 . Thus, in some embodiments, the adjustable end seal assembly  10  is constructed as a cartridge that can be moved (e.g., slid), as a single unit, into and out of an opening (e.g., a slot  900 ) delineated collectively by the extrusion die  100  and an end plate  80 . These embodiments provide for particularly quick and easy installation and removal of the adjustable end seal assembly  10 . 
     In the embodiment of  FIGS. 1-5 , the side member  48  and the end seal plate  56  are prevented from moving axially relative to each other. This is done by mounting two cross pins  400  in aligned bores passing through the end seal plate and the side member. Reference is made to  FIGS. 1-3 and 5 . The end seal plate  56  is allowed to slide a limited lateral distance along these pins  400 , i.e., toward and away from the side member  48 . As noted above, the drive member  46  in this embodiment is located between the side member  48  and the end seal plate  56 . The two cross pins  400 , however, do not pass through the drive member  46 . Rather, the drive member  46  is allowed to move axially (i.e., in either direction of arrow  500  in  FIG. 4 ) a limited distance relative to the side member  48  and the end seal plate  56 . 
     The adjustable end seal assembly  10  in the embodiment of  FIGS. 1-5  is designed for use on an extrusion die  100  having a restrictor bar. The end seal device  50  is therefore shaped to seal the area adjacent the restrictor bar. Referring to  FIG. 7 , it can be appreciated that the end seal device  50  has a trailing region  52  and a leading region  53 , and the trailing region is wider than the leading region. The trailing region  52  includes a shoulder area  51  configured to seal the area adjacent the restrictor bar. The illustrated gasket  58  and end seal plate  56  are also shaped in this manner (e.g., each have the same type of trailing region  52  and leading region  53 ). 
     A non-limiting method of making an adjustable end seal assembly will now be described. The end seal gasket is cut out in a shape to cover any flow opening at the end of the die. A solid metal push plate, i.e., the end seal plate (used to push the gasket against the end of the die), is cut in the same shape as the gasket. The drive member (which may be a drive plate) has an inclined plane machined into one side. The push plate (i.e., the end seal plate) is machined to accept a component that rides in the inclined plane, so as to spread the assembly and thereby apply pressure to the end of the die. The drive member is driven with a contained threaded spool, which will move the drive member in a linear motion. The components are held together with a shoulder bolt to allow the components to spread and contain the components that ride in the inclined plane. Given the present teaching as a guide, skilled artisans will appreciate that the adjustable end seal assembly can be made by other methods. 
     The invention also provides embodiments involving an extrusion die  100  equipped with an adjustable end seal assembly  10 . Reference is made to  FIGS. 6-18 . The extrusion die  100  has a die body  150 , an internal flow passageway  800 , and an outlet orifice  850 . The internal flow passageway  800  leads to the outlet orifice  850 . 
     The internal flow passageway  800  of the extrusion die  100  will commonly include a manifold  810 , a preland channel and a final land channel  820 . Reference is made to  FIGS. 12 and 13 . In these figures, the interface of the preland, secondary, and land are not shown. It is to be appreciated that the internal flow passageway need not include all of these sections. Rather, the internal flow passageway can be provided in various different forms, e.g., based on the extrusion processes the die is intended to carry out. 
     In the embodiments illustrated, the die body  150  includes two halves  125  between which the internal flow passageway  800  extends. Each illustrated half  125  of the die body  150  comprises a block having machined therein half of the internal flow passageway. Thus, when the two halves  125  of the die body  150  are joined together, the mating recesses in the confronting faces of these blocks collectively form the internal flow passageway. This is shown in  FIGS. 10 and 11 . 
     The die  100  can be provided in a variety of different forms, as will be appreciated by those skilled in this field. Thus, the adjustable end seal assembly  10  can be used with a variety of different dies; the basic style of the die itself is not limiting to the invention. 
     In the present embodiments, the adjustable end seal assembly  10  includes an end seal device  50  and a wedge mechanism  40 . The end seal device  50  closes (and when the illustrated assembly  10  is in an engaged configuration, seals) one lateral side of the internal flow passageway  800 . Thus, when the extrusion die  100  is operated, polymer or another extrudate flows through the internal flow passageway  800  and alongside the end seal device  50 . For example, extrudate flowing through the die  100  contacts the end seal device  50  as it flows downstream toward the outlet orifice  850 . As noted above, the end seal device  20  preferably comprises a gasket  58  positioned between an end region  159  of the die body  150  and the wedge mechanism  40 . In such cases, when the extrusion die  100  is operated, polymer or another extrudate flowing through the internal flow passageway  800  contacts the gasket  58  (e.g., at locations upstream from the outlet orifice). 
     The illustrated extrusion dies  100  each have opposed first and second lateral sides.  FIG. 6  shows one lateral side (the right side, as seen in  FIG. 6 ) of an extrusion die  100  in accordance with one embodiment of the invention.  FIGS. 16-18  show one lateral side (the right side, as seen in these figures) of an extrusion die  100  in accordance with another embodiment of the invention. Skilled artisans will appreciate that the die  100  typically has two opposed lateral sides each with its own end plate  80 . This is shown, for example, in  FIGS. 8-11 . Also,  FIG. 15  shows that both lateral sides of the extrusion die  100  in  FIGS. 16-17  have end plates  80 , each with its own adjustable end seal assembly  10 . While this will commonly be the case, it is not required. For example, one of the lateral die sides can have an adjustable end seal assembly while the other lateral die side has a conventional end seal. 
     In embodiments where the die  100  has two lateral sides each with its own adjustable end seal assembly  10 , the two end seal devices  50  of the assemblies  10  respectfully close (and when both assemblies are in an engaged configuration, respectfully seal) the two lateral sides of the internal flow passageway  800 . It will be understood that, in such embodiments, the two adjustable end seal assemblies  10  are on opposite lateral sides of the die  100 , while the outlet orifice  850  is on a front side of the die and extends between the two lateral sides of the die. 
     In the present disclosure, when the details of a single adjustable end seal assembly  10  are described, it is to be appreciated that those details apply equally well for each such assembly in cases where both lateral sides of the extrusion die  100  have adjustable end seal assemblies. The same is true of the end plate discussions and other discussions of components that are, or may be, present at each lateral side of the extrusion die. 
     The extrusion die  100  has opposed front and rear sides. As noted above, the outlet orifice  850  is on the front side of the die  100 . In some embodiments, when the adjustable end seal assembly  10  is in a disengaged configuration, a gasket  58  of the assembly is received loosely alongside the die body  150  (e.g., between the die body and an end seal plate  56  of the assembly  10 ) such that the gasket can be removed from the die  100  by simply pulling the gasket away from the rear side of the die. This can be appreciated by referring to  FIG. 14 , where the gasket  58  is shown exploded from the die  100  in a position it would occupy after being pulled from the die by an operator. The gasket can optionally have a small hole that can be hooked with a small wire or another similar tool. In this manner, the gasket can be easily pulled out of its position between the die  100  and the end seal plate  56 . The gasket  58  in  FIG. 14 , for example, has one such hole near each of its two ends. 
     The adjustable end seal assembly  10  has an engaged configuration and a disengaged configuration. When the assembly  10  is in the engaged configuration, its end seal device  50  is held forcibly against an end region  159  of the die body  150 . When the adjustable end seal assembly  10  is in the disengaged configuration, its end seal device  50  is either spaced apart from the end region  159  of the die body  150  or held against the end region of the die body with less force than when in the engaged configuration. Reference is made to  FIGS. 12 and 13 . The engaged configuration is shown in  FIG. 12 , and the disengaged configuration is shown in  FIG. 13 . 
     Preferably, when the adjustable end seal assembly  10  is in the engaged configuration, its end seal device  50  delivers a pressure of at least 15,000 pounds per square inch (psi) to the end region  159  of the die body  150 . In preferred embodiments, the pressure is 20,000 psi or greater. The amount of applied pressure, however, can be lesser or greater (e.g., depending upon the particular die and end seal configurations and the processes to be performed) as required to eliminate or minimize extrudate leakage from the lateral sides of the internal flow passageway  850 . 
     As noted above, the adjustable end seal assembly  10  preferably has a single-point actuator. In such cases, an operator can move the assembly  10  between the engaged and disengaged configurations by operating a single actuator. In addition, the actuator  20  and the die  100  preferably are constructed such that a person can operate the actuator without having to disassemble any part of the adjustable end seal assembly  10  or the extrusion die. 
     In the illustrated embodiments, the adjustable end seal assembly  10  has an actuator  20  on the rear side of the die  100 . This actuator  20  is operable to move the adjustable end seal assembly  10  between the engaged and disengaged configurations. Various actuator options have been described. 
     As noted above, the adjustable end seal assembly  10  includes a wedge mechanism  40  comprising both a drive member  46  and a side member  48 . The illustrated assembly  10  includes an elongated adjustment bar  30  extending from the actuator  20  on the rear side of the extrusion die  100  to the drive member  46 . In the illustrated embodiments, the adjustment bar  30  spans more than 30% of the total length of the assembly  10 . This is shown in  FIG. 4 . As discussed previously, the illustrated adjustment bar  30  moves axially in response to operation of the actuator  20 . The drive member  46  and the side member  48  move away from each other in response to axial movement of the adjustment bar  30  in a first direction. 
     In alternate embodiments, rather than having the actuator on the rear of the die, it can be on a lateral side of the die (e.g., on the end plate). In such cases, an adjustment bar may extend from the end plate to the drive member. There may be, for example, a camming connection between an adjustment bar of this nature and a drive member. In such cases, moving the adjustment bar further into the die may cause a camming action that forces the drive member to move toward the front of the die, whereas moving the adjustment bar in the opposite direction forces the drive plate to move toward the rear of the die. Various other side-mounted actuator systems can also be used. 
     In the embodiments of  FIGS. 6-18 , the adjustable end seal assembly  10  is housed in an end plate  80 . With respect to the embodiment of  FIGS. 6 and 7 , this is perhaps best shown in  FIG. 7 . With respect to the embodiment of  FIGS. 8-14 , this is best shown in  FIG. 9 . With respect to the embodiment of  FIGS. 15-18 , this is best shown in  FIG. 15 . In these embodiments, the end plate  80  has a slot  900  in which the adjustable end seal assembly  10  is mounted. The end plate  80  has spaced-apart confronting first and second wall sections  82  between which the slot  900  is located. Reference is made to  FIGS. 6 and 16 . 
     In  FIGS. 6-18 , the adjustable end seal assembly  10  can be inserted into, and removed from, the slot  900  as a single unit. Preferably, this can be done by simply sliding the adjustable end seal assembly  10  into the slot  900 , and later sliding it out of the slot. This is perhaps best appreciated by referring to  FIGS. 8 and 9 . 
     The adjustable end seal assembly  10  has an expanded profile when in the engaged configuration and a contracted profile when in the disengaged configuration. In the embodiments illustrated, the end plate  80  has a stop wall  88  that restrains (e.g., prevents) movement of the adjustable end seal assembly  10  in a lateral direction away from the die body  150 . Thus, when the adjustable end seal assembly  10  expands in moving from the disengaged configuration to the engaged configuration, the stop wall  88  of the end plate  80  bears against the assembly  10 , thereby limiting (e.g., preventing) its movement laterally away from the die  100  and hence forcing the assembly  10  to expand in the direction of the die. In connection with the embodiment of  FIGS. 6 and 7 , this is best shown in  FIG. 6 . In connection with the embodiment of  FIGS. 8-14 , this is perhaps best shown in  FIG. 11 . In connection with the embodiment of  FIGS. 15-18 , this is perhaps best shown in  FIG. 15 . 
     In the embodiments illustrated, the stop wall  88  of the end plate  80  comprises a rigid surface that, when abutted by the adjustable end seal assembly  10 , prevents the assembly  10  from expanding away (or further away) from the die body  150 . The rigid surface faces toward the die body. In the embodiments of  FIGS. 6-14 , each end plate  80  has two stop walls  88 . In these embodiments, the two stop walls  88  are configured as spaced apart, confronting (e.g., inwardly turned) shoulders, each defining a rigid surface facing toward the die body  150 . The adjustable end seal assembly  10 , when operatively mounted on the die  100 , is carried against the rigid surfaces of these two shoulders. Thus, when the assembly  10  expands, the expansion causes the end seal device  50  to move toward the die  100 . 
     In the embodiment of  FIGS. 15-18 , each end plate  80  has a single stop wall  88 . This stop wall  88  connects the confronting first and second wall sections  82  between which the slot  99  is formed. The stop wall  88  has a rigid surface that, when abutted by the adjustable end seal assembly  10 , prevents the assembly  10  from expanding away (or further away) from the die body  150 . The rigid surface faces toward the die body. The adjustable end seal assembly  10 , when operatively mounted on the die  100 , is carried against this rigid surface. Thus, when the assembly  10  expands, the expansion causes the end seal device  50  to move toward the die  100 . 
     In the embodiments of  FIGS. 6-14 , each end plate  80  comprises spaced-apart first and second rail plate segments  85 . In these embodiments, when an adjustable end seal assembly  10  is operatively mounted on the die  100 , it is mounted between (e.g., so as to be embraced by) two rail plate segments  85 . This is perhaps best shown in  FIGS. 6, 7, and 9 . In these embodiments, the above-noted slot  900  is a gap between the two rail plate segments  85 . 
     The slot  900  between the two rail plate segments  85  preferably has a configuration matching the shape of the adjustable end seal assembly  10 . This is shown, for example, in  FIG. 7 . In this embodiment, the slot  900  is configured so as to have a trailing region and a leading region, where the leading region is narrower than the trailing region. The trailing region is adjacent to the rear side of the die, and the leading region is adjacent to the front side of the die. The end plate  80  has a stop shoulder  81  against which the adjustable end seal assembly  10  bears when the assembly  10  is moved to its operative position in the slot  900 . 
     The rail plate segments  85  are shown as independent bodies, which are attached separately to the die  100 . The first rail plate segment  85  is anchored to a first  125  of the two halves of the die body  150 , and the second rail plate segment  85  is anchored to a second  125  of the two halves of the die body. In these embodiments, the first rail plate segment  85  defines the above-noted first wall section  82 , and the second rail plate segment  85  defines the above-noted second wall section  82 . 
     In the embodiment of  FIGS. 15-18 , the die body  150  has an elongated internal passage that opens to the slot  900  of the end plate  80 . In this embodiment, the adjustable end seal assembly  10 , when operatively mounted on the die  100 , has a leading portion (e.g., adjacent to the front of the die) received in the slot  900  of the end plate  80  and a trailing portion (e.g., adjacent to the rear of the die) received in the elongated internal passage of the die body  150 . In more detail, the two halves  125  of the die body  150  have mating elongated slots  130  that, when coupled together, form the elongated internal passage in which the trailing portion of the assembly  10  is received. In the present embodiment, the outlet orifice  850  has a shorter lateral length than the die body  150 . The die  100  in this embodiment has a projecting front region that defines the two die lips  120 . This projecting front region is shown having a generally triangular configuration, which tapers to a narrow front end at the outlet orifice  850 . In the present embodiment, this projecting front region has a shorter lateral length than the rear portions of the die body halves  125 . In more detail, the die body  150  has two lateral side extensions  127  in which the two adjustable end seal assemblies  10  are respectfully mounted. The internal flow passageway  850  does not pass through these lateral side extensions  127 . Rather, the internal flow passageway is located inwardly of (e.g., spaced apart from) the two lateral side extensions  127 . This is best shown in  FIG. 16 . 
     In the present embodiment, the end plates  80  are located forward of the die&#39;s lateral side extensions  127 . Each illustrated end plate  80  has an inside wall carried against an end region  159  of the die body  150  and a rear wall carried against a front wall of the adjacent lateral side extension  127 . Thus, the slot  900  of the end plate  80  and the adjacent internal passage of the die body  150  collectively form an elongated mount opening (extending between the rear and front sides of the die) in which the adjustable end seal assembly  10  can be mounted. 
     In the embodiment of  FIGS. 15-18 , the side member  48 /end seal plate  56  is prevented from moving axially together with the drive member  46  by virtue of a cross pin projecting from the end plate  80  and extending through a slot in the side member  48 /end seal plate  56 . This cross pin, while preventing the side member  48 /end seal plate  56  from moving axially, allows it to move laterally toward and away from the die  100  (e.g., in response to the wedging action of the assembly  10 ) to an extent limited by the length of the slot in the side member  48 /end seal plate  56 . 
     The invention also provides methods of using an extrusion die having an adjustable end seal assembly. In one embodiment, the invention provides a method of operating an extrusion die  100  having a die body  150 , an internal flow passageway  800 , and an adjustable end seal assembly  10  including an end seal device  50 . The extrusion die  100  and the adjustable end seal assembly  10  of the present method can be of the nature described above. 
     The method involves moving the adjustable end seal assembly  10  from a disengaged configuration to an engaged configuration by operating a single actuator  20 . As discussed previously, when the adjustable end seal assembly  10  is in the engaged configuration, the end seal device  50  is held forcibly against an end region  159  of the die body  150 , and when the adjustable end seal assembly is in the disengaged configuration, the end seal device is either spaced apart from the end region of the die body or held against the end region of the die body with less force than when in the engaged configuration. 
     The adjustable end seal assembly  10  expands in moving from the disengaged configuration to the engaged configuration. For example, this may involve the end seal device  50  of the adjustable end seal assembly  10  moving from a retracted position to an extended position. Reference is made to  FIGS. 12 and 13 . The end seal device  50  in  FIG. 13  is in a retracted position, while the end seal device  50  in  FIG. 12  is in an extended position. 
     The present method involves operating a single actuator  20  of the adjustable end seal assembly  10 . This causes the end seal device  50  to simultaneously apply substantially uniform pressure to multiple points about the end region  159  of the die body  150 , thereby sealing a lateral side of the internal flow passageway  800 . In the embodiments illustrated, the end seal plate  56  moves in its entirety against the end region  159  of the die body  150  in response to operating the single actuator  20 . The actuator  20  preferably is on the rear side of the die  100 . 
     When the adjustable end seal assembly  10  is in the engaged configuration, the end seal device  50  preferably applies a pressure of at least 15,000 psi to the end region  159  of the die body  150 . In some cases, the applied pressure is 20,000 psi or more. 
     The actuator  20  may be operated by rotating an actuator body on the rear side of the extrusion die  100  and thereby forcing an adjustment rod  30  coupled with the actuator body to move axially toward or away from a front side of the extrusion die. This axial movement of the adjustment rod  30  causes a drive member  46  and a side member  48  of the adjustable end seal assembly  10  to move relative to each other. This creates a wedging action that forces the drive member  46  and the side member  48  to move away from each other. The details of the actuator  20  and adjustment rod  30  movements, and the resulting wedging action of the drive member  46  and the side member  48  (and the optional camming members  45 ), were discussed previously. 
     Some embodiments of the present method also involve operating the extrusion die  100  such that extrudate flows through the internal flow passageway  800  and alongside the end seal device  50 . As noted above, in the embodiments illustrated, extrudate flowing through the internal flow passageway  800  contacts a gasket  58  of the adjustable end seal assembly  10 . 
     Finally, some embodiments of the present method also involve moving the adjustable end seal assembly  10  from the engaged configuration to the disengaged configuration by operating the single actuator  20  of the adjustable end seal assembly  10 . In certain embodiments of this nature, a gasket  58  of the adjustable end seal assembly  10  is then received loosely alongside the die body  150 . In such embodiments, the method can further involve removing the gasket  58  from the extrusion die  100  by simply pulling the gasket  58  away from a rear side of the extrusion die. Embodiments of this nature were discussed previously in connection with  FIG. 14 . 
     While certain preferred embodiments have been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.