Abstract:
A trim press article handling apparatus includes a punch plate, a die plate, a plunger, and a receiver. The punch plate has a punch, and the die plate has a die cooperating in relative movement with the punch plate to sever articles from a thermoformable web. The plunger is carried by one of the punch plate and the die plate having a tapered advancing head. The receiver is carried by the other of the punch plate and the die plate having a tapered recess configured to receive the plunger. A tapered article locator provided within a thermoformed web also having articles therein is captured between the plunger and the receiver as the punch plate and die plate are brought together there about, thereby imparting alignment of an article in the web between the punch and the die. A method for aligning and severing articles from a web is also provided.

Description:
TECHNICAL FIELD 
     This invention pertains to an apparatus and method for separating thermoformed thin-walled articles from sheets of plastic or foam material. More particularly, this invention relates to a trim press article handling apparatus such as a web processing article registration device. 
     BACKGROUND OF THE INVENTION 
     Various devices are known for trimming thin-walled articles from sheets of thermoformed plastic material. The trimming or severing of such articles from a continuous web or sheet of thermoformable plastic and/or foam material has long been known in the art. For example, U.S. Pat. No. 4,526,074 discloses a high-speed trim press for successively trimming thermoformed articles from a continuous web of thermoformable foam or plastic material. A male locator urges the thermoformed article and web against a cutter in order to trim individual articles from the web. In the process, the articles are retained in a recess within the cutter. Subsequently trimmed articles form a state of nested articles within the recess. However, the cooperating male and female members in such trim press do not necessarily cut with sufficient accuracy, especially during high-speed trim press operations. Accordingly, improvements are needed to enhance the accuracy with which articles are aligned within a trim press such that the articles properly register with individual complementary punches and dies that cooperate to cut articles from a web. 
     SUMMARY OF THE INVENTION 
     A device is provided for registering articles, or products, during a web processing operation. More particularly, an article registering device more accurately positions web-supported articles into a trim press prior to and while severing the articles from the web. Such article registering device provides an additional degree of accuracy during such severing operation over that previously provided via adjustment and control of a web conveyor. 
     According to one aspect, a trim press article handling apparatus includes a punch plate, a die plate, a plunger, and a receiver. The punch plate has a punch, and the die plate has a die cooperating in relative movement with the punch plate to sever articles from a thermoformable web. The plunger is carried by one of the punch plate and the die plate having a tapered advancing head. The receiver is carried by the other of the punch plate and the die plate having a tapered recess configured to receive the plunger. A tapered article locator provided within a thermoformed web also having articles therein is captured between the plunger and the receiver as the punch plate and die plate are brought together there about, thereby imparting alignment of an article in the web between the punch and the die. 
     According to another aspect, a web processing article registration device includes a first support structure, a second support structure, a plunger, and a receiver. The first support structure has a punch, and the second support structure has a die configured to cooperate with the punch to sever articles from a web of thermoformable material. The plunger is carried by one of the first support structure and the second support structure, and has a tapering, leading head portion. The receiver is carried by another of the first support structure and the second support structure, and has a recess configured to receive the plunger. A tapering article locator and at least one article are provided within a web such that the tapering article locator is captured between the plunger and the receiver as the punch and the die are moved together such that the plunger interacts with the tapering article locator to align the article between the punch and the die to facilitate aligned severing of the article therebetween. 
     According to yet another aspect, a method is provided for aligning and severing articles from a web of thermoformable material includes: forming at least one article and a tapering recess within a web of thermoformable material; providing a trim press having a punch plate with a punch, a die plate with a die, a plunger carried by one of the punch plate and the die plate, and a receiver carried by the other of the punch plate and the die plate; receiving the formed web between the punch plate and the die plate; aligning the article between the punch and the die by moving the punch plate and the die plate so as to engage the plunger with the tapering recess such that the plunger and the receiver cooperate with the tapering recess to align the article with the punch and the die; and severing the article from the web by coacting the punch and the die while the article is aligned therebetween. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with reference to the following accompanying drawings. 
     FIG. 1 is a vertical side view of a thermoforming machine trim press having an article registration device embodying one aspect of the invention; 
     FIG. 2 is a series of illustration views of a sheet of thermoformable plastic material in which articles are formed using a thermoforming machine and from which such articles are trimmed, or severed, aligned, and stacked using the apparatus of FIG. 1; 
     FIG. 3 is a schematic perspective view taken in an upwards direction of a top platen illustrating associated components of the article registration device configured to cooperate with the bottom platen of FIG. 4; 
     FIG. 4 is a schematic perspective view taken in a generally downwards direction of a bottom platen illustrating associated components of the article registration device configured to cooperate with the components on the top platen of FIG. 3; 
     FIG. 5 is an enlarged, simplified and schematic perspective view illustrating a thermoformed plastic web containing a plurality of thermoformed articles therein and article locator features, and further illustrating cooperation of the components for the article registration device of FIGS. 3 and 4 cooperating to align the articles with punch and die components of the trim press of FIG. 1; 
     FIG. 6 is a vertical sectional view taken along line  6 — 6  of FIG.  5  and showing the punch plate and die plate configured to align and sever an article from a web of material; 
     FIG. 7 is an enlarged and partial vertical cross-sectional view taken along line  7 — 7  of FIG. 5 illustrating a punch plate and die plate in an open position prior to aligning a web of material and articles formed therein in relation to the punch plate and die plate during a trim press operation; 
     FIG. 8 is an enlarged and partial vertical cross-sectional view taken along line  7 — 7  of FIG. 5 corresponding with the view of FIG. 6 showing the punch plate being lowered such that the article registration device moves the web of material into alignment such that corresponding articles are aligned between the punch plate and die plate; 
     FIG. 9 is an enlarged and partial vertical cross-sectional view taken along line  7 — 7  of FIG.  5  and corresponding with the views of FIGS. 7 and 8, and illustrating complete closure of the punch plate and die plate during a completed severing operation of an article, wherein the article registration device has aligned the web and articles accurately between the punch plate and die plate during a severing operation. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). 
     Reference will now be made to a preferred embodiment of Applicant&#39;s invention. One exemplary implementation is described below and depicted with reference to the drawings comprising an article registration device and method for aligning and severing articles from a web of thermoformable material. While the invention is described by way of a preferred embodiment, it is understood that the description is not intended to limit the invention to this embodiment, but is intended to cover alternatives, equivalents, and modifications such as are included within the scope of the appended claims. 
     In an effort to prevent obscuring the invention at hand, only details germane to implementing the invention will be described in great detail, with presently understood peripheral details being incorporated by reference, as needed, as being presently understood in the art. 
     A preferred embodiment of Applicant&#39;s invention is shown on a thermoforming machine trim press that is generally designated with reference numeral  10  in FIG.  1 . More particularly, an article registration device is provided on trim press  10  to more accurately align articles during severing of the articles from a web. A control system  12  choreographs operation of trim press  10  along with a conveyor  19  in order to move a web  14  of thermoformed plastic material in which individual articles, or products,  16  have earlier been formed using a thermoforming machine (not shown). In operation, web  14  is driven in intermittent motion using control system  12  to intermittently feed individual rows of articles  16  to a reasonably accurate position where the articles  16  are severed from web  14  using trim press  10 . During closure of trim press  10 , article registration device  15  more accurately position articles  16  with respect to punch and die members just prior to severing the articles  16  from web  14 . 
     An article accumulator  72  is also provided on trim press  10  to accumulate the severed articles  16  into individual stacks  18 , which are intermittently deposited atop a stacking conveyor  20  for delivery to a packing machine. Such stacks  18  of articles  16  are then loaded into individual packages or plastic bags. 
     Further details of article accumulator  72  are provided in Applicant&#39;s co-pending U.S. patent application Ser. No. 09/576,219, entitled “Article Stacking Device, Trim Press Article Accumulator, and Method of Stacking Thermoformed Articles”, naming Jere F. Irwin as inventor, and filed concurrently herewith. Such U.S. patent application Ser. No. 09/576,219 is herein incorporated by reference. 
     In order to improve the accuracy with which articles  16  are severed from a web by trim press  10 , article registration device  15  is provided on trim press  10  having desired features of Applicant&#39;s invention. Article registration device  15  provides highly accurate article registration between punch plate  28  and die plate  30  to ensure that articles  16  are accurately severed from web  14 . Accordingly, articles  16  are severed in a highly uniform and centered manner from web  14  such that a uniform flange is provided about such articles when articles  16 , for example, comprise plastic plates. 
     In the absence of Applicant&#39;s article registration device  15 , article registration is carried out solely by adjusting the positioning of a web conveyor  19 , as shown and described below in simplified form. Additionally, a coarse level of article registration is carried out by adjusting the operation of controller  40  in order to adjust the advancement and positioning of individual articles between punch plate  28  and die plate  30 . 
     However, it is oftentimes very difficult to adjust the set-up and component positioning for a web conveyor in order to accurately and precisely deliver articles  16  between punch plate  28  and die plate  30 . Hence, article registration implemented solely using conveyor set-up and control does not sever such articles in a sufficiently uniform and accurate manner. Furthermore, there are limitations to the accuracy with which a servo motor can drive web conveyor  19 , and therefore, in the ability of such servo motors to accurately place articles  16  between punch plate  28  and die plate  30 . Oftentimes, it is the case that articles  16  are off by several millimeters, which can produce an undesirable effect, particularly where article  16  is of a complicated shape, or article  16  comprises a foldable container having a hinge which requires a high degree of accuracy in forming and severing thereof. 
     Accordingly, article registration device  15 , as described below with reference to FIGS. 3-9, provides an enhanced ability to accurately register articles  16  between punch plate  28  and die plate  30  when severing such articles  16  therebetween. 
     As shown in FIG. 1, web conveyor  19  is illustrated in simplified form as a drive wheel assembly  21  including a servo motor (not shown) that is controllably actuated via control system  12  to impart intermittent motion to web  14 . As shown in FIG. 1, drive wheel assembly  21  comprises two pairs of co-acting top and bottom wheels that are provided along opposite side edges of web  14 . A topmost wheel of each pair comprises a drive wheel and a bottom-most wheel of each pair comprises a follower wheel that is actuated and driven by a servo motor. Accordingly, actuation of drive wheel assembly  21  via controller  40  is operative to intermittently deliver rows of articles  16  into trim press  10 . Such rows of articles  16  are then severed as control system  12  actuates a severing operation via trim press  10 . Subsequently, a scrap web  22  is delivered from trim press  10  and ground into small pieces using a comminuting device configured for grinding up scrap web  22 , as described below in reference to FIG.  2 . 
     As shown in FIG. 1, drive wheel assembly  21  comprises a dual servo motor driven roller feed assembly. However, it is understood that drive wheel assembly  21  represents a simplified version of a web conveyor for delivering thin web materials into trim press  10 . One exemplary detailed construction for a web conveyor is disclosed in U.S. Pat. No. 5,806,745, herein incorporated by reference. 
     Several different comminuting apparatus suitable for grinding up scrap web  22  are disclosed in U.S. Pat. Nos. 4,687,144; 5,836,527; 5,860,607; and 5,893,523, each herein incorporated by reference. Scrap web  22  is accordingly forwarded into such a recycling, pulverizing machine where web  22  is shredded and then later recycled to form a new web of thermoformable plastic material. 
     Details of one exemplary thermoforming machine suitable for forming articles  16  within web  14  are disclosed in U.S. Pat. No. 5,773,540. U.S. Pat. No. 5,773,540 is herein incorporated by reference. 
     Trim press  10  includes a movable upper platen  24 , a stationary lower platen  26 , a punch plate  28 , and a die plate  30 . Punch plate  28  is carried for movement by movable upper platen  24 , whereas die plate  30  is fixedly carried by stationary lower platen  26 . However, it is understood that platen  26  and die plate  30  can also be movably supported for operation according to an alternative construction. 
     As shown in FIG. 1, upper platen  24  is carried for vertical reciprocation by crank arm assemblies  32 - 35 . Details of one exemplary thermoforming machine suitable for incorporating accumulator  72  and having such crank arm assembly are shown in U.S. patent application Ser. No. 08/691,856, now U.S. Pat. No. 6,067,886, entitled “Machine Trim Press Having Counterbalance Features”, and naming the inventor as Jere F. Irwin. Such U.S. Pat. No. 6,067,886 is herein incorporated by reference. 
     Each crank arm assembly  32 - 35  comprises a throw arm  36  and a platen connecting rod  38 , wherein arm  36  and rod  38  cooperate to form a kinematic linkage that drives a dedicated corner of platen  24  for vertical, guided reciprocation. Additionally, two cylindrical, stationary guide posts (not shown) are rigidly carried by a frame  11  to support platen  24  for movement in an axial, vertical direction. Optionally, only four guide posts can be configured to support platen  24  with two corresponding bushings. 
     Even furthermore, four additional, stationary guide posts  60 - 63  (see FIG. 3) are rigidly supported or press fit within apertures  64 - 67  of die plate  30  to further guide sliding movement of punch plate  28  there along. Bushings  164 - 167  (of FIG. 3) in punch plate  28  slide over guide posts  60 - 63 . Such platen guide posts (not shown) are understood in the art and have been omitted from the figures in order to simplify the drawing and to prevent obscuring the invention at hand. Furthermore, punch plate/die plate guide posts  60 - 63  have been eliminated from FIG. 1 to also prevent obscuring the invention at hand. 
     Control system  12  of FIG. 1 includes a controller  40  having processing circuitry  42  and memory  44 . According to one construction, processing circuitry  42  is provided by a central processing unit (CPU). According to another construction, processing circuitry  42  is provided by a microcontroller which cooperates to form controller  40 . It is understood that memory  44  is operative to store software subroutines that are retrieved and implemented on processing circuitry  42  in order to impart motion control functionality by way of controller  42  to trim press  10 . 
     As shown in FIG. 1, control system  12  is operative to generate control signals that direct operation of a servo drive motor  46  that drives crank arm assemblies  32 - 35  and thereby imparts reciprocation to upper platen  24 . Servo drive motor  46  comprises a highly accurate computerized servo motor and servo drive which can be accurately driven by control system  12 . In operation, servo drive motor  46  drives a gear box  48  that imparts a rotary motion to each of crank arm assemblies  32 - 35 . Furthermore, control system  12  is operative to deliver a control signal to a servo drive motor  50  that advances article conveyor  20 . Additionally, control system  12  delivers another control signal to a plurality of linear actuators  52  that raise and lower article conveyor  20  as well as stacks  18  of severed articles  16  during stacking, packaging and/or bagging operations. One suitable linear actuator  52  comprises a plurality of ball screw actuators having electric drive motors. Alternatively, linear actuator  52  comprises a plurality of pneumatic or hydraulic actuators, or pistons, configured to raise and lower article conveyor  20  relative to lower platen  26 . 
     FIG. 2 illustrates in simplified schematic form the processing of a thermoformable plastic web  14  wherein web  14  is initially heated in an oven after which individual articles  16  are formed in the heated web using a thermoforming machine. Subsequently, rows  54  of articles  16  are successively severed from web  14  and stacked using a trim press  10  (of FIG. 1) having the novel features of Applicant&#39;s invention. Pairs of article locators  87  and  89  in web  14  facilitate accurate severing of articles  16  from web  14 . Accumulator  72  then stacks successive rows  54  beneath web  14 , after which an array  58  of stacks  18  of articles  16  is retrieved from beneath web  14  by activating conveyor  20  (of FIG.  1 ). Scrap web  22  is progressively advanced forward into a comminuting apparatus as described above, which generates subdivided pieces  56  of a sufficiently small desired size. 
     As shown in FIG. 3, punch plate  28  coacts with die plate  30  of FIGS. 4-9 when severing and accumulating articles. Punch plate  28  includes bronze bushings  164 - 167  that are fitted in slidable engagement over guide posts  60 - 63 , respectively. Accordingly, punch plate  28  is movably supported along guide posts  60 - 63 , and is further driven by crank arm assemblies  32 - 35  via servo drive motor  46  and gearbox  48  (of FIG.  1 ). As shown in FIG. 3, a plurality of punches, or male die members,  96  are provided on a bottom surface of punch plate  28 . Punches  96  are individually arranged so as to coact with die member  94  of lower platen  26  (of FIG.  4 ). Accordingly, such coaction between cutting edges  68  and  98  severs articles from a web in an accurate manner as plungers  100  and  102  cooperate with article registration cavities  90  and  92  to center article locators  87  and  89  within web  14  (see FIG.  2 ), which causes articles  16  in web  14  to also be accurately aligned between punches  96  (see FIG. 3) and corresponding dies present within die member  94  (see FIG.  4 ). Accordingly, coaction between corresponding cutting edges  98  on each punch  96  (of FIG. 3) and complementary cutting edges  68  of die member  94  (of FIG.  4 ), in combination with article alignment between plungers  100  and  102  and article locators  87  and  89 , ensures accurate severing of articles from a web. Following such severing, such articles are stacked by way of accumulator  72  (see FIG.  1 ). 
     Accordingly, article registration plungers  100  and  102  cooperate with substantially complementary article registration cavities  90  and  92  (of FIG. 4) in order to laterally align a web and corresponding web-formed articles accurately between punch plate  28  (of FIG. 3) and die plate  30  (of FIG.  4 ). It is understood that such lateral alignment occurs in two dimensions as article locators  87  and  89  taper with depth so as to form a frustoconical or funnel-shaped cavity which imparts alignment to articles  16  (see FIG. 5) in a two-dimensional plane corresponding with the plane of web  14 . 
     As shown in FIG. 5, article registration plunger  100  (as well as plunger  102 ) cooperates with substantially complementary article registration cavity  92  (as well as cavity  90 ) in order to align web  14  and articles  16  between die plate  30  and punch plate  28  (of FIG.  3 ). As shown in FIG. 5, it is understood that plunger  102  is carried for vertical reciprocation by punch plate  28  (of FIG.  3 ). 
     FIG. 6 illustrates an alignment and severing operation as carried out between punch plate  28  and die plate  30  when severing individual articles  16  from web  14  by coaction of cutting edges  68  and  98 . More particularly, downward movement of plungers  100  and  102  causes aligned registration of tapered article locators  87  and  89  in all directions lying in the plane of web  14 . More particularly, plungers  100  and  102  are lowered in a downward axial direction, causing centering of tapered article locators  87  and  89  there about, which also pulls web  14  and articles  16  into aligned registration there about. Such aligned registration of web  14 , and cavities  90  and  92  between plungers  100  and  102 , and locators  87  and  89 , also imparts precise and accurate alignment of articles  16  between cutting edge  98  of punch  96  and cutting edge  68  of individual dies in die member  94 . Accordingly, improvements are imparted by increasing the accuracy with which individual articles are severed between punch plate  28  and die plate  30 . As shown in FIG. 6, severed articles  16  are released through coaction of gravity through article cavity  70  where they are accumulated there below on an article conveyor (not shown). 
     FIG. 7 illustrates the assembly of article plunger  102  on a bottom surface of punch plate  28 , and the construction of article registration cavity  92  above die plate  30 . As shown in FIG. 7, web  14  has been advanced between punch plate  28  and die plate  30  wherein a formed article (not shown) is about to be severed between punch plate  28  and die plate  30 . Misalignment is present between such article (not shown) and the associated cutting surfaces of punch plate  28  and die plate  30 , as indicated by the misalignment of tapered article locator  87  in relation to article registration cavity  92 . It is understood that the positional relationship between an article formed in web  14  and tapered article cavities  87  and  89  corresponds precisely with the positional location of cutting surfaces in punch plate  28  and die plate  30  relative to article registration cavities  90  and  92 . 
     Likewise, plungers  100  and  102  are supported positionally in punch plate  28  in relation to the position of tapered article locators  87  and  89  when articles (not shown) in web  14  are accurately aligned with such cutting edges. Hence, plunger  102  is axially, downwardly displaced such that plunger  102  engages with misaligned tapered article locator  87 , causing lateral alignment of locator  87  along with web  14  and any articles formed therein, as illustrated below with reference to FIGS. 8 and 9. 
     As shown in FIG. 7, plunger  102  (as well as plunger  100 ) is constructed with an aluminum central retainer  85  having an outwardly biased shoulder  104 , a threaded aperture  99 , and a hemispherical end portion  93 . An ultra-high molecular weight (UHMW) polyethylene, or plastic, outer sleeve  88  is entrapped by central retainer  85  onto punch plate  28 . More particularly, a coil steel spring  91  downwardly biases outer sleeve  88  until an inwardly extending shoulder  106  on outer sleeve  88  engages with shoulder  104  of central retainer  85 . 
     In assembly, a threaded fastener  86  is received within a fastener aperture  97  of punch plate  28  so as to retain and assemble plunger  102  onto a bottom surface of plunger plate  28 . Spring  91  is compressively biased between a bottom surface of punch plate  28  and a hemispherical circumferential sleeve shoulder  95  of outer sleeve  88 . Accordingly, outer sleeve  88  is downwardly biased from punch plate  28 , until coaction of plunger  102  causes upward biasing of outer sleeve  88  through coaction with tapered article locator  87  and article registration cavity  92 , as shown in FIGS. 8 and 9. 
     As further shown in FIG. 7, article registration cavity  92  (as well as cavity  90 ) comprises a frustoconical aperture  82  and a cylindrical aperture  84 . According to one construction, hemispherical circumferential sleeve shoulder  95  of outer sleeve  85  tapers inwardly in a radial direction such that downward biasing of plunger  102  into tapered, or tapering, article locator  87  will impart alignment of web  14  and associated articles with respect to frustoconical aperture  82 . However, it is understood that frustoconical aperture  82  and hemispherical circumferential sleeve shoulder  95  can have different tapered shapes as long as such tapering imparts alignment as plunger  102  is downwardly biased into tapered article locator  87  and frustoconical aperture  82 . Likewise, article locator  87  can optionally have a modified shape, and perhaps even a cylindrical shape if such shape coacts with plunger  102  to cause alignment of articles. Further optionally, plunger  102  can have a relatively square, or flat, head as long as tapering article locator  87  coacts with such head so as to impart alignment of a web and articles therein in response to coaction therebetween. 
     As shown in FIGS. 7-9, hemispherical end portion  93  and outer sleeve  88  of plunger  102  form a compound curved surface. More particularly, hemispherical circumferential sleeve shoulder  95  has a bifurcated taper including a distal, relatively steep angle taper (relative to the central axis of the plunger) at the leading end and a proximal, relatively shallow angle taper (relative to the central axis of the plunger) toward plate  28 . The distal, relatively steep angle taper initiates contact with article locator  87  in order to impart an initial coarse alignment (and large-scale lateral displacement) of articles in web  14 . The proximal, relatively shallow angle taper subsequently contacts with article locator  87 , as plunger  102  is stroked deeper into article locator  87  and frustoconical aperture  82  in order to impart a subsequent fine alignment (and small-scale lateral displacement) of articles in the web. 
     In further alternative constructions, it is understood that article registration cavity  92  can comprise a single cylindrical aperture, or other variously shaped, oversize aperture. However, the provision of frustoconical aperture  82  further ensures the accurate alignment of articles in web  14  in relation to cutting surfaces on punch plate  28  and die plate  30 . 
     FIG. 8 illustrates the lowering of punch plate  28  during an article severing operation of a trim press. In such case, plunger  102  initiates engagement with tapered article locator  87 , causing lateral alignment of web  14  (and associated articles therein) relative to punch plate  28  and die plate  30 . As shown in FIG. 8, plunger  102  initiates contact such that plunger  102  is compressively biased in an upward axial direction as punch plate  28  is lowered further into contact with die plate  30  and finally into complete compression, as illustrated in FIG.  9 . Such coaction causes lateral movement of web  14 , which causes corresponding article alignment between punch plate  28  and die plate  30 . 
     FIG. 9 illustrates a completely closed stage between punch plate  28  and die plate  30  wherein plunger  102  is completely compressed, and web  14  is accurately aligned therebetween. As shown in FIG. 9, tapered article locator  87  is accurately positioned within article registration cavity  92 , which also coincides with accurate registration of articles between cutting edges of punch plate  28  and die plate  30 . 
     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.