IN-MOLD LABELING OF INJECTION BLOW MOLDED HOLLOW PLASTIC ARTICLES

Abstract: A method and apparatus for placement of labels (4) within the blow molds (24) of an injection blow molding machine. The injection blow molding machine comprising a turret (20) having plurality of circumferentially spaced surfaces (21), each of which supports a plurality of spaced core rods (22), a plurality of injection molds (23) at a injection molding station for forming a plurality of preforms, and a plurality of blow mold sections (24) at a blow molding station which close about the preforms so that the preforms can be blown outwardly against the confines of the mold to form hollow plastic articles. The blow molds (24) include movable bases exposing the interior of the blow molds when the blow molds are closed about preforms on the core rods (22). A positioning apparatus (26) positions a plurality of labels (4) at the blowing station and a plurality of cylindrical vacuum mandrels (27) are rotated to pick-up the labels and thereafter the mandrels are translated to deliver the labels to the blow molds (24) through the open bottoms after which the mandrels (27) are retracted, the mold bottoms are closed and the hollow articles are blown in the molds with the labels on the outer surfaces thereof.

Description: This invention relates to a method of applying a label to an article which is made by injection molding a preform and thereafter blowing the preform to the confines of the mold as defined in the preamble of claim 1 and to an in-mold labelling apparatus as defined in the preamble of claim 7. One common type of machine for blow molding hollow articles is known as an injection blow molding machine wherein a core rod is inserted successively into an injection mold to form a preform or parison and is thereafter used to transfer the parison to a blow mold where the parison is blown outwardly against the confines of the mold to form hollow plastic article such as a container. In one type of injection blow molding machine, a turret has a plurality of circumferentially spaced surfaces, for example, three surfaces, each of which supports a plurality of spaced core rods. When the turret is rotated, the core rods are moved successively first to a preform or injection station having an array of preform or parison molds, then to a blow molding station having an array of blow molds where the parisons are blown to form the hollow articles, and finally to an unload station where the hollow articles are removed from the core rods permitting a new cycle to begin. In various blow molding machines, it has heretofore been suggested that labels be positioned in the hollow blow molds before blowing the hollow article so that the final article has a label applied to the exterior surface thereof. An injection molding machine of the above general type is known from US-A-4668177. From US-A-3151193 there is known a method and apparatus for applying labels to blown plastic articles. The method disclosed consists of applying printed matter to blown plastic articles comprising the steps of removing at least part of a die in which the article is to be formed, applying printed polythene film to the inner face of the removed part of the die, replacing the removed part of the die with film applied thereto in the die body, delivering a charge of plastic to the die, closing the die and blowing the article. The apparatus, in turn, comprises a die, at least a portion of which may be withdrawn from the die body, a vacuum mandrel for applying printed polythene film to the withdrawn portion of the die, means for delivering a charge of plastic material to the die, means for closing the die and means for blowing the article. Accordingly, among the objectives of the present invention are to provide a method and apparatus for in-mold labelling in an injection blow molding machine wherein the in-mold labelling can be achieved without reducing the normal operating cycle and wherein the labels can be accurately positioned both longitudinally and circumferentially with respect to the parting line of the blow molds. The invention therefore provides a method of applying a label to an article which is made by injection molding a preform and thereafter blowing the preform to the confines of the mold which comprises: positioning a label adjacent to the open end of the closed blow mold in which a core rod is positioned having a preform thereon; wrapping the label about a vacuum mandrel; placing the label within the closed mold; closing the end of the mold; and blowing the preform outwardly to provide an article having a label thereon, characterised in that the label is placed in the closed mold by: inserting the vacuum mandrel with the label thereon into the open end of the closed mold; releasing vacuum on the vacuum mandrel such that the label is released within the mold; and removing the mandrel from within the open end of the closed mold. Additionally, the invention provides an in-mold labelling apparatus, for use in an injection molding apparatus comprising a turret having a plurality of circumferentially spaced surfaces, each of which supports a plurality of spaced core rods, a plurality of injection molds at a injection molding station for forming a plurality of preforms, and a plurality of blow mold sections at a blow molding station which close about the preforms so that the preforms can be blown outwardly against the confines of the molds to form blow molded articles, comprising: a base movable to close the ends of the molds; means for positioning a label adjacent to each mold; a vacuum mandrel mounted adjacent to each mold; and means for simultaneously rotating the vacuum mandrels to pick up their respective labels; characterised in that the means for positioning the labels comprises a vacuum conveyor; and by further comprising means for simultaneously axially moving the vacuum mandrels into the open end of the closed molds to deliver a label to each mold. The invention is now disclosed in greater detail according to a preferred embodiment with reference to the attached drawing table, wherein the figures show the following : FIG. 1 is a partly diagrammatic plan view of an injection blow molding machine embodying the invention. FIG. 2 is a fragmentary perspective view of a portion of the apparatus. FIG. 3 is a fragmentary plan view of a portion of the apparatus. FIG. 4 is a fragmentary plan view of a portion of the apparatus on an enlarged scale. FIG. 5 is a fragmentary elevational view of the portion of the apparatus shown in FIG. 4. FIG. 6 is a fragmentary sectional view taken along the line 6-6 in FIG. 5. FIG. 7 is a fragmentary sectional view taken along the line 7-7 in FIG. 5. FIG. 8 is a fragmentary sectional view taken along the line 8-8 in FIG. 5. FIG. 9 is a part sectional view of the vacuum mandrel utilized in the apparatus. FIG. 10 is a partly diagrammatic end view of the vacuum mandrel. FIG. 11 is a fragmentary elevational view of a portion of the apparatus shown in FIG. 3. FIG. 12 is a fragmentary plan view of a portion of the apparatus shown in FIG. 11. FIG. 13 is a fragmentary part sectional view on an enlarged scale of the portion of the apparatus shown in FIG. 3. FIG. 14 is a sectional view taken along the line 14-14 in FIG. 11. FIG. 15 is a fragmentary view taken along the line 15-15 in FIG. 3. FIG. 16 is a fragmentary view taken along the line 16-16 in FIG. 15. FIG. 17 is a fragmentary view taken along the line 17-17. FIG. 18 is a perspective view of a container with a label applied thereto utilizing the apparatus of the present invention. FIG. 19 is a longitudinal sectional view of a container shown in FIG. 18. FIG. 20 is a plan view of a modified form of apparatus. FIG. 21 is a front elevational view of the apparatus shown in FIG. 20. FIG. 22 is a fragmentary sectional view taken along the line 22-22 in FIG. 20. Referring to FIG. 1, the injection blow molding machine includes a turret 20 that has three circumferentially spaced surfaces 21, each of which supports a plurality of spaced core rods 22. The turret 20 is rotated in counterclockwise direction bringing the core rods 22 to a first preformed station A having an array of parison molds 23, where the parisons P are injection molded, then to a blow mold station B having an array of blow molds 24 where the parisons are blown to form the hollow articles, and finally, to a station C where the hollow articles are removed from the core rods permitting a new cycle to begin. Referring to FIGS. 1-3, in accordance with the invention, the blow molds 24 are formed with movable bottom plates 25 to expose the interior of the molds 24 after they have been closed about the cores 12. In addition, a positioning device 26 positions a plurality of labels, one adjacent each blow mold 24. Cylindrical vacuum mandrels 27 are brought into position and rotated to pick-up the labels from the positioning device 26. The cylindrical mandrels 27 with the labels thereon are thereafter translated axially to deliver the labels through the open bottoms of the molds 24 and thereafter are retracted after which the base plates 25 are closed permitting the hollow articles to be blown outwardly and resulting in hollow articles which have a label thereon, in the manner shown in FIG. 18. For purposes of clarity, only one of the blow molds 24 and associated mandrels 27 is shown and described in the following description and associated drawings. Each of the mandrels 27 has a drive and each of the blow molds 24 has associated bottom plates. Referring to FIGS. 4-8, the positioning apparatus 26 comprises an endless vacuum belt 28 which is trained over pulleys 29, 30 mounted in a frame 31 that is pivoted at one end to supports 32 mounted on a plate 33. A cylinder 34 has its body pivoted as at 35 to an upright 36 mounted on the plate 33 and has its piston rod 37 pivoted as at 38 to the frame 31 50 that the vacuum belt can be moved upwardly at the right end as viewed in FIG. 5 into position for registering with the vacuum mandrel 27. The vacuum belt 28 is provided with longitudinally spaced holes 39 which register with openings 41 of a vacuum manifold 42 that extends along the upper reach of the belt 28 between the pulleys 29, 30. The manifold is supported within the frame 31 and is supplied with vacuum through a connection 42. The belt 28 is provided with a longitudinally extending rib 43 that registers with grooves 44, 45 in the pulleys and a space 46 in the manifold. Pulley 30 is driven by a pulley 47 on the shaft 48 thereof which in turn is connected by a belt 49, pulley 50, shaft 51 and pulley 52, belt 53 and pulley 54 driven by motor 55 on a plate 56. The vacuum belt 28 is driven intermittently to bring a plurality of labels thereon in a position adjacent the blow molds. Referring to FIG. 9, each mandrel 27 comprises a cylinder which has a longitudinally extending opening 56a and is removably mounted by threaded connection 57 on the end of a shaft 58. The mandrel 27 includes spaced longitudinally extending slots 27a which are connected by radial openings 59 to associated longitudinally extending openings 60, each of which opens at the end opposite the open end to a vacuum chamber provided in a collar 62 that is mounted on spaced shafts 63 fixed on a body 64. Springs 65 yieldingly urge the manifold 62 against the end of the mandrel 27. Vacuum is applied to the chamber 61 through a tubular connection 66. As shown in FIG. 10, as the mandrel rotates and the vacuum conveyor 28 is moved, the leading edge of a label L registers with one of the slots 58 so that as the mandrel is then rotated, the trailing edge of the label is engaged by the other slot 58 to hold the label in position. The indexing and registry of the mandrel and conveyor is maintained, as presently described. Referring to FIG. 13, the shaft 58 on which the mandrel 27 is mounted comprises rotatably mounted in a first bracket 67 by bearing 68 and the portion 58b is rotatably mounted in a second bracket 69 by bearing 70. Brackets 67, 69 are adjustably mounted longitudinally on rods 71, 72. The rods 71, 72 are in turn mounted on spaced brackets 73, 74 mounted on plate 56. The ends of the rods 71, 72 are interconnected by a bracket 76 that spans the ends. In this manner, the rod 58 is reciprocable between a position overlying the conveyor and a position wherein the mandrel is within a blow mold. A gear 77 is mounted on the portion 58b of shaft 58 and is interconnected thereto by a key 78 extending into an elongated keyway 79 so that the shaft can be rotated by rotation of the gear 77 and maintains such rotation during reciprocation of the shaft 58. The gear is in turn rotatably mounted by sleeve 79a and bearings 80 on brackets 74. Gear 77 meshes with a gear 81 on the shaft 51 (FIG. 2). Reciprocation of the shaft 58 and associated mandrel is achieved by drive wherein a rack 82 is mounted on a plate 83 supported by post 84 above the plate 56 and is guided for longitudinal reciprocation parallel to the shaft 58. The end of the rack 82 is connected to a bracket 84 on the block 64 which is mounted on the bracket 67. The rack 82 is formed with upwardly facing longitudinally spaced teeth 85 which are engaged by a gear 86. The gear 86 also engages a second rack 87 having longitudinally spaced teeth and supported in fixed position on the plate 83 by housing 88. The gear 86 is fixed on a bifurcated bracket 89 mounted on the system 90 of a linear motor 91 so that upon reciprocation of the shaft 90, the gear 86 racks along the rack 87 to translate the rack longitudinally and in turn move the shaft 58 and associated mandrel longitudinally between the position overlying the conveyor 28 and position within the blow mold. In a typical sequence the following steps occur: 1. Molds closed, bottom plate open, labels on conveyor, mold vacuum on; 2. Index vacuum transfer conveyor, vacuum on; 3. Left vacuum transfer conveyor; 4. Rotate mandrel, vacuum on and simultaneously index conveyor, vacuum off to transfer a label from the conveyor to the mandrel; 5. Lower vacuum transfer conveyor, vacuum on; 6. Insert mandrel with label into mold; 7. Blow off label into mold; 8. Retract mandrel; 9. Index mandrel to original position; 10. Close mold bottom plate; 11. Blow container; 12. Open mold and remove container. Referring to FIGS. 15-17, the apparatus for moving the bottom plates 25 into and out of position for closing the open end of the blow mold comprises a cylinder 100 associated with each plate. The plate 25 is mounted for movement and is guided by cam rollers 101, 102 operating in a longitudinally extending track 103 and mounted on a operating plate 104 fixed to the shaft 105 of the cylinder 101. Operating plate 104 further includes a cam roller 106 that engages an angularly extending slot 107 in the bottom plate 25. Upon reciprocation of the shaft 105, the operating plate 104 moves along the track 103 and causes the roller 106 to shift the bottom plate 25 radially of the mold sections 24 to bring the bottom plates into overlying relation with the ends of the mold sections 24 thereby closing the bottom. After the vacuum plunger 27 has deposited a label within the open ended blow mold 24. In operation, the positioning apparatus 26 moves a label L to a position in registry with the mandrel 27 which is in overlying relationship to the vacuum belt 28. The end of the associated blow mold is open and the core rod 12 is within the mold with a parison P thereon. The positioning apparatus 26 is tilted upwardly bringing the label into registry with the mandrel so that rotation of the mandrel will wrap the label about the mandrel after which the mandrel is moved longitudinally within the mold, the vacuum is disconnected, and the label is thereby released within the mold. The bottom plates are then closed and the blow molding can then proceed to blow the parison into a container G with the label adhered to the outer surface of the container G. In the form of apparatus shown in FIGS. 20-22, a plurality of mandrels 27 are mounted for rotation on a support 110 and are interconnected by chains 111 to a splined drive shaft 112. The splined shaft 112 extends through a pulley 113 which, in turn, is driven through a belt 114 by a pulley 115 on motor 116 to rotate the mandrels 27 in accordance with the method and thereby pick up labels in unison from the positioning conveyor 26a. Support 110 is mounted for movement toward and away from the molds by an arrangement which includes a rack 117 on the support 110. A gear 118 is mounted on the shaft 119 of a linear actuator 120 and meshes with a fixed rack 121 so that upon actuation of the actuator 120, the mandrels can be driven in unison toward and away from the molds. Conveyor 26a is mounted on bell cranks 122 operated by motor 123 and connected by a rod 124 to raise the conveyor 26a to bring the labels into position for engagement with the mandrels. It can thus be seen that there has been provided a method and apparatus for in-mold labeling in an injection blow molding machine wherein the in-mold labeling can be achieved without reducing the normal operating cycle and wherein the labels can be accurately positioned both longitudinally and circumferentially with respect to the parting line of the blow molds.

Claims: A method of applying a label (L) to an article (G) which is made by injection molding a preform (P) and thereafter blowing the preform (P) to the confines of the mold (24) which comprises: positioning a label (L) adjacent to the open end of the closed blow mold (24) in which a core rod (22) is positioned having a preform (P) thereon; wrapping the label (L) about a vacuum mandrel (27); placing the label (L) within the closed mold (24); closing the end of the mold (24); and blowing the preform (P) outwardly to provide an article (G) having a label (L) thereon, characterised in that the label (L) is placed in the closed mold (24) by: inserting the vacuum mandrel (27) with the label (L) thereon into the open end of the closed mold (24); releasing vacuum on the vacuum mandrel (27) such that the label (L) is released within the mold (24); and removing the mandrel (27) from within the open end of the closed mold (24). A method according to claim 1 which includes blowing air through the vacuum mandrel (27) while it is in the mold (24) to blow the label (L) outwardly against the mold (24). A method according to claim 1 or claim 2 wherein the positioning of the label (L) is achieved by utilizing a vacuum conveyor (26) and by rotating the mandrel (27) while simultaneously advancing the conveyor (26) to transfer a label (L) from the conveyor (26) to the mandrel (27). A method according to claim 3 including moving the conveyor (26) relative to the mandrel (27) to bring the surface of the conveyor (26) carrying the label (L) adjacent to the mandrel (27). A method according to any preceding claim in which a label (L) is so applied to each of a plurality of such articles (G). A method according to claim 5 in which the plurality of labels are simultaneously applied. An in-mold labelling apparatus, for use in an injection molding apparatus comprising a turret (20) having a plurality of circumferentially spaced surfaces (21), each of which supports a plurality of spaced core rods (22), a plurality of injection molds (23) at an injection molding station for forming a plurality of preforms (P), and a plurality of blow mold sections (24) at a blow molding station which close about the preforms (P) so that the preforms (P) can be blown outwardly against the confines of the molds (24) to form blow molded articles (G), comprising: a base (25) movable to close the ends of the molds (24); means (26) for positioning a label (L) adjacent to each mold (24); a vacuum mandrel (27) mounted adjacent to each mold (24); and means for simultaneously rotating the vacuum mandrels (27) to pick up their respective labels (L); characterised in that the means for positioning the labels comprises a vacuum conveyor (26); and by further comprising means for simultaneously axially moving the vacuum mandrels (27) into the open end of the closed molds (24) to deliver a label (L) to each mold (24). An in-mold labelling apparatus according to claim 7 including means for moving the surface of the conveyor (26) carrying the labels (L) toward and away from the mandrels (27). An in-mold labelling apparatus according to claim 8 including means for rotating each mandrel (27) and simultaneously advancing the conveyor (26) to transfer a label from the conveyor (26) to the mandrel (27). An in-mold labelling apparatus according to any one of claims 7 to 9 wherein each mandrel (27) includes a longitudinally extending slot (58) for engaging a leading edge of a label (L) on the conveyor (26).

Inventors: KAMINSKI, RONALD S., NOWICKI, CASIMIR W., SIDO, WILLIAM F.
Applicants: OWENS-ILLINOIS PLASTIC PRODUCTS INC.
Application year: 1988
Main classification: B29C49
IPC codes: B29C49