Abstract:
An apparatus for deflashing plastic blow molded articles is disclosed. The apparatus includes feed screw which engage one side of the container to move the container. A nesting wheel and a trim wheel are rotated in opposite directions to bring trim tools and nest tools together. The screw moves the container so that the nest tool engages the container and carries the container so that it is between the nest tool and trim tool as they intermesh. As a result, the container is nested, trimmed and released in one continuous motion.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to blow molding machinery and more particularly to an apparatus for automatically removing flash from extrusion blow molded, plastic objects. 
     During the extrusion blow molding process, flash is often formed along a portion of the parting line of the molded object. For example, the bottom or base of the container may have a “tail” which is the result of clamping the plastic extruded between the two mold halves. There is also generally unwanted plastic flash attached to the top of the container adjacent to where the threads of the container are formed. If the container has a handle, the section between the handle and the container also contains a web of plastic material corresponding in thickness to two layers of the original parison. 
     Although there have been a number of different approaches taken to solve the problem of removing flash from extrusion blow molded plastic containers, each of the prior art approaches is complicated and costly. Also, if these prior art devices are not properly operated, the deflasher apparatus can damage the container and render it unacceptable. 
     These deflashing operations must be performed rapidly and reliably and the apparatus performing the operation must be compact and capable of handling containers at a rate equal to the rate at which the extrusion blow molding machine produces the containers. Also, transfer and trimming of the containers requires that the bottles be accurately oriented prior to deflashing to permit trimming without damage to the container sidewall or bottom. The deflashing apparatus must be compact to minimize factory floor space. None of the known prior art devices are able to meet all of the above requirements. 
     Therefore, there is a need for a compact apparatus that is preferably in-line with the blow molding machine so as to minimize floor space, and one that is capable of deflashing containers in one continuous motion at a rate equal to the rate at which the blow molding machine produces the containers. 
     SUMMARY OF THE INVENTION 
     The present invention is a novel rotary deflashing apparatus for plastic, blow molded articles. The deflashing apparatus is a dual rotary trimmer having two balanced, continuously counter-rotating wheels, namely a nest tool wheel and an intermeshing trim tool wheel. A screw advances the articles sequentially into engagement with the trimmer whereby the articles are deflashed of the tail, body, and the top flash when the nest tool is in juxtaposed position with the trim tool. 
     It is an object of the present invention to provide a trimmer that is simpler than prior art devices and is capable of deflashing articles of top flash, body flash, and tail flash at a rate equal to the rate at which the blow molding machine produces the articles. 
     It is another object of the present invention to provide a trimmer that is compact in size and continuous in operation to maximize throughput. 
     A still further object of the present invention is to provide a trimmer that picks up the article, removes all of the flash from the article and releases the deflashed article in one continuous motion. 
     These and other objects of the present invention will become apparent to one skilled in the art upon reading the following specification and by reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the deflashing apparatus according to the invention; 
     FIG. 2 is an enlarged side view of the deflashing apparatus according to the invention; 
     FIG. 3 is a top view of the apparatus with articles being advanced into engagement with the nest tool at approximately 90 degrees to the through line between the two wheels; 
     FIG. 4 is a top view similar to FIG. 3 with the wheels of the apparatus having been advanced through about 45 degrees of rotation; 
     FIG. 5 is a top view of a second embodiment of the apparatus with the articles being advanced into engagement with the nest tool at approximately 30 degrees to the through line between the two; 
     FIG. 6 is a top view of a third embodiment where the articles are being advanced into engagement with both the nest tool and trim tool at 0 degrees or in-line with the through line between the two wheels; 
     FIG. 7 is an enlarged view of the apparatus showing the nest tool on the second wheel and trim tool on the first wheel; 
     FIG. 8 is a side elevational view of an article (with top, body, tail and handle flash) held in the nest tool prior to deflashing; 
     FIG. 9 a  is a top view of the nest tool with an article being rotated and with the trim tool engaging the leading edge; 
     FIG. 9 b  is a top view of the article partially deflashed and held between the nest tool and trim tool; 
     FIG. 10 is a top view of the article partially deflashed and held between the nest tool and the trim tool and beginning to deflash the trailing edge of the article; 
     FIG. 11 is a side view of the article seen in FIG. 9 b  with tail and top flash partially removed; 
     FIG. 12 is a side view similar to FIG. 11 with the tail flash removed and the top flash nearly completely removed; 
     FIG. 13 is a side view of the tail flash trimmer; 
     FIG. 14 is a side view of the nest tool; 
     FIG. 15 is a top view of the nest tool; 
     FIG. 16 is a side view of the trim tool; 
     FIG. 17 is a top view of the trim tool; 
     FIG. 18 is a top view of the tail flash trimmer; 
     FIG. 19 is a side view of an embodiment of a dual tail flash trimmer; and 
     FIG. 20 is a side view of an embodiment of a trim tool construction for heavy flash. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As used herein, an article or container A is an extrusion blow molded, plastic, article such as, but not limited to, milk containers, bottles, toys, storage tanks, decorative trim objects, prescription bottles and other objects. 
     The present apparatus  100 , as seen in FIG. 1, includes an infeeder  2  and a rotary trimmer  30  for deflashing blow molded containers A (having flash designated at F). The flash F of the container may include the body flash, top flash, and tail flash. The tail flash (further designated as T) is a thin plastic section at the parting line of the mold halves which is the excess remains of the extruded parison during the molding process. Optionally, the container A may also have handle flash depending on the design of the container A. 
     The infeeder  2  moves the containers A longitudinally and in an upright manner from the molding machine (not shown) on a split conveyor  4 . To orient the container A onto the split conveyor  4 , the container A is discharged from the molding machine so that the tail flash T extends between the parallel, spaced apart tracks of the split conveyor  4  so that the tail flash T of the container A prevents it from turning or twisting out of orientation. 
     From the conveyor  4 , the containers A are transferred onto a support plate  11  and are picked up or engaged by counter-rotating feed screws  12 . The screws  12  have flights or threads  14  which are sized to capture the container A therebetween. The pitch of the screw threads  14  are designed to capture, space and move the container A from the split conveyor  4  into engagement with the rotary trimmer  30 . The pitch is preferably variable, increasing along the length of the screws  12 , to accelerate and spread out the containers A before they enter the trimmer  30 . The height of the support plate  11  is at the same height above the frame as the surface of the split conveyor  4  so that the container A moves in the same longitudinal plane from the conveyor  4  to the support plate  11 . At the ends of each screw are the side rails  19  which guide the side of the container A and prevent the container A from moving transversely out of its desired orientation. 
     The container A is moved by screws  12  along a longitudinal axis  18  which defines an angle α, which can be varied relative to the through line axis  40 , as shown in FIGS. 3 through 6. The axis  40  is defined as the longitudinal extension of the meshing tangent point of the two wheels  34  and  44  of the rotary trimmer  30 . In its most preferred embodiment, the angle α is 90 degrees relative to the through line axis  40 , as shown in FIGS. 3 and 4. 
     The infeeder&#39;s screws  12 , as seen in FIGS. 3-5, may have different lengths in order to permit the rotary trimmer  30  to rotate and engage the containers A. This is particularly the case when axis  18  is not aligned with axis  40 . In the aligned configuration of FIG. 6, each of the screws  12  may have the same length provided the diameter of the screws  12  is such that they permit the rotary trimmer  30  to rotate into and engage the containers A without interference. 
     The trimmer  30  includes a pair of counter-rotating wheels  34 ,  44  supported on a frame  7 . The first of counter-rotating wheels, wheel  34 , carries a series of nest tools  50  and the second wheel, trim wheel  44 , carries a series of trim tools  70 . 
     The nest wheel  34  and the trim wheel  44  are supported on vertical shafts each having a drive wheel on its lower end supported by conventional bearings. The drive wheels of the nest and trim wheels  34 ,  44  are driven by one or more drive belts, chains or gears, so that they are counter-rotating and synchronized in relation to one another. The vertical shafts, drive wheels and belts are not illustrated in the figures for the sake of clarity with respect to the other elements illustrated therein. Such illustration is not believed necessary since persons skilled in the art will readily appreciate a variety of possible drive trains and schemes after having the benefit of this disclosure. 
     The nest wheel  34  and the trim wheel  44  each are provided with the same number of equidistantly spaced pairs of arms  33 ,  43  extending radially therefrom. The number of arm pairs  33 ,  43  will depend on the rate at which containers A are to be deflashed and will preferably be between two and forty-eight, although this range is given only by way of example and is not to be considered a limitation on the number of arm pairs  33 ,  43 , or individual arms that can be used to practice the invention. Preferably, there are four arm pairs  33 ,  43  on each of the wheels  34 ,  44 . 
     As shown in FIGS. 14 and 15, a nest tool  50  is mounted to a support plate  56  connected by conventional fasteners to the ends of the arm pairs. The nest tool  50  itself includes a mounting plate  52  which enables securement to the plate  56  on the arm pairs  34 ,  44 . The nest tool  50  is segmented and includes a body portion  53  defining a cavity  54 , a top support portion  58  located above the body portion  53  and a bottom portion  59  which is located above the cavity  54 . Depending on the container A, the cavity  54  may also define a handle portion. As such, a container A with flash F fits into and is closely held by the body cavity  54  preventing it from being dislodged out of the cavity  54 . The neck N of the container A rests against or within the support portion  58  and the tail flash T extends below the bottom portion  59  as shown in FIGS. 7,  11  and  12 . For a container A with a handle and flash H, these portions fit into the optional handle portion of the nest tool  50 . The body portion  53  and bottom portion  59  cooperate to define a recess  61 , as seen in FIGS. 2,  7 ,  11 ,  12  and  14 . The recess  61  provides clearance to enable the trim tool  50  to swing by the inboard screw  12  without interference. 
     The trim tool  70  is mounted to a vertical support plate  72  secured to the ends of the arm pairs  43  by conventional fasteners. This is shown in FIGS. 16 and 17. The trim tool  70  has a mounting plate  71  which secures it to the plate  72  mounted on the ends of the arm pairs  43 . The trim tool  70  includes a top trim knife  78 , a handle trim knife  56  and a tail trimmer assembly  80 . 
     As stated earlier, the container A is captured in the nest tool  50  so that the flash F extends above and below the tool  50 . As the nest tool  50  and the trim tool  70  rotate into juxtaposed engagement with each other, the top trim knife  78 , having an arcuate edge, cuts off top flash D which extends beyond the top portion  58  in a manner which prevents the neck N of the container A from moving. The cutting edge of the top trim knife  78  shears off the flash D from the container A nested in the nest tool  50  as the nest tool  50  and trim tool  70  rotate past and intermesh with each other. As the cutting edge of the knife  78  swings through its arc of motion, it shears and/or pushes the flash D radially from the parting line on the container A toward the nest tool  50  as the nest tool  50  on the first wheel  34 , and the trim tool  70  on the second wheel  44 , are rotated into and meet each other at the plane along axis  40 . Those skilled in the art will recognize that because the extruded blow molded flash plastic material is brittle, the flash F, in general, may be pressed off and/or cut off by the trim tool  70  and pushed toward the nest tool  50 . Optionally, the nest tool  50  is provided with biasing means (not shown) to push the trimmed flash away from the nest tool  50  after the nest tool  50  and trim tool  70  have rotated past one another and are no longer in juxtaposed position. In achieving the above, it is noted that the knife  78  extends from the trim tool  70  a distance such that its cutting edge is beyond the part line on the container A, where the flash is still attached thereto. 
     In a like manner, any additional flash F along the top of the container shoulder may be sheared off at the container by leading and trailing cutting edges  75 ,  73 , located immediately below the top trim knife  78 . 
     Handle flash H is trimmed by the handle trim knife  76 . The handle trim knife  76  is sized to be received within the handle opening formed in the container A and at least its cutting edges  77  protrude beyond the parting line of the container A thereby insuring that the handle flash H is severed away from the handle. 
     The tail trimmer assembly  80  is seen in FIGS. 7,  11 ,  12  and  13 . For clarity, the assembly has been omitted from FIGS. 16 and 20. The assembly is cam actuated and includes a fixed portion mounted to the frame  7 , and a rotated portion, identical assemblies of which are carried by each trim tool  70 . 
     The fixed portion includes a cam  82  mounted to a bracket  84  that secures the cam  82  to the frame  7  in a fixed position. The cam  82  includes a cam surface defining a radial face with respect to the rotational axis of the trim wheel  44 . 
     The second or rotated portion of the tail trimmer assembly  80  includes a blade  83  which is moveably supported with respect to the remainder of the trim tool  70 . Blade  83  is supported on pins  86  located within bores  88  of mounting blocks  90  that are themselves secured to the actual trim tool  70 . Blade  83  is biased by springs or other suitable means  89  such that the biasing retracts the blade  83  towards the axis of rotation of the trim wheel  43 . Extending downward from the blade  83  is a follower  85 . 
     As the trim tools are rotated by the trim wheel  43 , the follower  85  is brought into engagement with the cam surface  87  of the cam  82 . Continued rotation of the trim tool  70  results in the follower  85  progressing radially outward along the cam surface  87  against the biasing of the springs. This radial outward movement of the follower  85  results in the blade  83  being radially moved outward as well. Outward movement of the blade brings the cutting edge  89  of the blade into engagement with the tail flash T as the tool  70  is rotating into juxtaposed position with the nest tool  50 . When the follower  85  clears the cam  82 , the blade  83  is retracted radially back toward the remainder of the trim tool  70  by the biasing member  89 . 
     Optionally, the tail trimmer apparatus  80  may include a second tail trimmer apparatus  80 ′, similar to apparatus  80  but located in association with the nest tool  50 . The second tail trimmer tool  80 ′ is identical in all respects to apparatus  80  and those elements used in apparatus  80 ′ that are the same are provided with a prime (′) designation. Thus, when the tail flash T is very thick, the first cam actuator device  82  and the second cam actuator device  82 ′ are engaged simultaneously near the meshing point of the trim tool  70  and the nest tool  50  to shear the tail flash T, as shown in FIG.  19 . 
     As a further embodiment, the tail trimmer apparatus  80  may include one cam actuated trimmer  80 , as described in connection with FIG. 18, and a second tail trimmer tool which is not cam actuated. Rather, the knife of the second tool may be fixed in position relative to the nest and trim tools and the first tail trimmer  80 . As yet another embodiment, only a single, fixed position tail trimmer is used. In this alternative, the tail trimmer does not rotate with the nest and trim tools. Rather, a fixed position knife relies on the over travel of the tail flash, as it is rotated past the knife, to shear the tail flash from the container. 
     Optionally, the entire trim tool  70  may be slidably supported on support pins  91  which extend radially from the vertical support surface  71 , as shown in FIG.  20 . The mounting plate  72  is then provided with close fit holes which permits it to slide on the support pins  91 . The trim tool  70  is then also configured to operate in association with the cam  82  so that when follower  85  engages cam  82 , the trim tool  70  slides outward along the support pins  91  to deflash the container A. This sliding movement of the trim tool  70  is especially advantageous since it adds radial shear force to the tangential shear force to further assist in deflashing a container A with heavy flash F. A spring  93  and pin  95  coupled to the trim tool  70  via the support plates  72  and mounting plate  71  return the tool  70  to a retracted position after engagement with the cam  82 . 
     Referring back to FIG. 3, after the nest tool  50  and the trim tool  70  are rotated away from each other, the deflashed container A is removed from the nest tool  50  at an outfeeder  102 . The outfeeder  102  is preferably one or more side rails  104  which strip the deflashed container A out of one of the tools  50 ,  70  and transfers the container A to a filling machine or a bottle accumulation station or a stacker device. The side rails  104  cooperate with a bottom rail  106  located at the same longitudinal plane as the nest tool  50  and trim tool  70  so that as the deflashed container A is released by either the nest tool or the trim tool, the container A is smoothly moved onto the bottom rail  106  for support of the deflashed container A. Alternatively, the deflashed container A is dropped downward into a basket (not shown) where the containers A are accumulated, for use at a later date or the deflashed container is moved onto an outfeeder conveyor device (not shown). Optionally, the container A can be held in either the nest tool  50  or trim tool  70  through a degree of rotation to permit the container A to be moved to a differently oriented outfeeder device  102 . 
     As an alternative to the outfeeder  102  having side rails  104 , an outfeeder can be provided in a manner similar to the infeeder&#39;s screws  12  as previously discussed. The outfeeder can therefore employ two outfeed screws or a single screw and rail combination. Additionally, the orientation of the outfeeder may be between 0° and 90° relative to the axis  40 . 
     Notably, with infeeder  20  at an angle of 90 degrees to the longitudinal axis  40  of the trimmer  30 , as shown in FIGS. 3 and 4, this facilitates the engagement of the container A with the nest tool  50  prior to the trim tool  70  meshing with the nest tool  50 . The segmented nest tool  50  and it&#39;s associated recess  61  permits the body cavity  54  to sweep over the top of the inboard of the screws  12 , and the bottom and tail body portion sweep below this screw  12 . Alternatively, where the diameter of the screw  12  is greater than the gap between the body cavity  54  and the bottom and body portion, the inboard side guide rail  19  is provided adjacent to the shortened screw  12 . The inboard rail thickness is less than the gap and permits the nest tool to rotate past it. The inboard rail  19  thus guides the container A along the longitudinal axis  18  as the second screw  22  advances the container A toward the trimmer  30 , until picked up by the nest tool  50 . 
     While the above preferred embodiment illustrates the invention, it is understood that this invention is capable of other modifications and therefore the invention is not limited to the precise detail set forth in the embodiments but falls within the changes and alterations that fall within the purview of the following claims.