Side shuttle apparatus and method for an injection molding machine | Patent Publication Number 20050271765
US 20050271765 A1James A. Vanderploeg
Nicholas Seston
Servo side shuttle apparatus and method for a molding machine includes structure and/or steps whereby a shuttle plate has a portion always disposed inboard of a perimeter of a first mold half of the molding machine. Drive structure is preferably configured to drive the shuttle plate only in one plane across a molding face of the first mold half. A plurality of gripping structures are coupled to the shuttle plate and are respectively configured to remove a corresponding plurality of molded articles from a corresponding plurality of mold cavities (or cores). The drive structure is also configured to drive the shuttle plate to cause the plurality of gripping structures to be moved in a direction which is diagonal with respect to an array direction of the plurality of mold cavities (or cores).
- 1. Molding machine side shuttle apparatus, comprising: na shuttle plate having a portion always disposed inboard of a perimeter of a first mold half of the molding machine; a drive structure configured to drive said shuttle plate only in one plane across a molding face of the first mold half; and a plurality of gripping structures coupled to said shuttle plate and respectively configured to remove a corresponding plurality of molded articles from a corresponding plurality of mold cavities, said drive structure being configured to drive said shuttle plate to cause the plurality of gripping structures to be moved in a direction which is diagonal with respect to an array direction of the plurality of mold cavities.
- 9. Molded article removal apparatus, comprising: na plate coupled to a first mold half of a molding machine and having a portion always disposed inboard of a perimeter of the first mold half, said plate including a removal device that is configured to grasp the molded article from at least one of a mold core and a mold cavity; and drive structure configured to be coupled to the plate, and configured to drive said plate (i) such that said plate is driven simultaneously in two orthogonal coplanar linear directions, and (ii) such that said removal device removes the molded article from the at least one of the mold core and the mold cavity.
- 20. Molded article removal apparatus, comprising: na first shuttle plate configured to be coupled to a mold portion, and including a first plurality of molded article gripping devices that are configured to remove a corresponding first plurality of molded articles from one of (i) a first plurality mold cores and (ii) a first plurality of mold cavities; a second shuttle plate configured to be coupled to the mold portion, and including a second plurality of molded article gripping devices that are configured to remove a corresponding second plurality of molded articles from one of (i) a second plurality mold cores and (ii) a second plurality of mold cavities; and drive structure configured to be coupled to the mold portion, and configured to drive said first and second plates in opposite directions, each opposite direction being diagonal to an array direction of one of (i) the first plurality mold cores and (ii) the first plurality of mold cavities.
- 23. A injection molding machine, comprising: na mold cavity plate having a plurality of mold cavities; a mold core plate having a plurality of mold cores; a driver for opening and closing the mold core plate and the mold cavity plate with respect to each other; injection structure configured to inject molten plastic into said plurality of mold cavities; molded part evacuation structure configured to evacuate molded articles from the injection molding machine; and a shuttle device configured to move linearly between the mold core plate and the mold cavity plate when they are separated by a predetermined clearance, said shuttle device being configured to extract a plurality of molded articles from the plurality of cavities or the plurality of cores, said shuttle device having at least a portion thereof inboard of a periphery of the mold cavity plate when the mold core plate and the mold cavity plate are in the closed position, said shuttle device configured to move diagonally with respect to an array direction of said plurality of mold cavities.
- 25. Molding machine side shuttle apparatus, comprising: nshuttle means having a portion always disposed inboard of a perimeter of a first mold half of the molding machine, for shuttling between the first mold half and a second mold half when the mold halves are in an open position; drive means for driving said shuttle means linearly, whereby said shuttle means is moved only linearly across the molding face of the first mold half; and operation means coupled to said shuttle means and configured to remove a molded article from one of a mold core and a mold cavity said drive means also for driving said operation means in a direction diagonal to an array direction of the one of a mold core and a mold cavity.
- 26. In a molding machine having a first mold half presenting a row of mold surfaces substantially aligned with each other and configured to form molded articles thereon, a molded article shuttling apparatus, comprising: na shuttle body configured to have a portion always disposed inboard of a perimeter of the first mold half of the molding machine, and to remove a row of molded articles, each molded article being located on a respective mold surface of the row of mold surfaces; and a drive structure configured to drive the shuttle body having the removed row of molded articles only in one plane across a molding face of the first mold half and along a direction diagonally aligned with respect to the alignment of the row of mold surfaces.
- 32. Molded article shuttling apparatus comprising: na shuttle body configured to: (i) have a portion always disposed inboard relative to a perimeter of a first mold half of a molding machine, the first mold half having a row of mold surfaces substantially aligned with each other and configured to form molded articles thereon; and (ii) remove a row of molded articles, each molded article being located on a respective mold surface of the row of mold surfaces; and a drive structure configured to drive the shuttle body having the removed row of molded articles only in one plane across a molding face of the first mold half and along a direction being diagonally aligned with respect to the alignment of the row of mold surfaces.
- 38. A method of removing a plurality of molded articles from one of (i) an array of mold cavities, and (ii) an array of mold cores, comprising the steps of: driving a shuttle plate in between a mold core half and a mold cavity half to a position where a plurality of grippers coupled to the shuttle plate may remove the plurality of molded articles from the one of (i) the array of mold cavities, and (ii) the array of mold cores; nusing the grippers to grip the molded articles and remove them from the one of (i) the array of mold cavities, and (ii) the array of mold cores; and driving the shuttle plate in a direction diagonal to an array direction of the one of (i) the array of mold cavities, and (ii) the array of mold cores, to a substantially co-linear position over a single drop chute.
1. Field of the Invention
The present invention relates to apparatus and method for performing operations on one or more molded articles in one or more mold cavities and/or mold cores. More particularly, the present invention relates to a side shuttle apparatus and method whereby various in-mold operations (such as extracting the plastic molded articles from their mold cavities or cores, applying labels to the plastic molded articles, providing various inserts into the mold cavity, closing or moving a cap of a molded container, etc.) can be quickly and easily carried out.
2. Related Art
In the injection molding art, it is desirable to carry out various operations on the just-molded plastic articles while they are still resident (or partially resident) in their respective mold cavities (or on their respective mold cores). For example, it would be advantageous to provide structure for removing the just-molded articles, for adding product labels, for providing various structural inserts, for rotating or manipulating the molded article in some way, conducting part inspection using a vision system, in-mold decoration (e.g. priming, painting), transfer molded articles from one molding position to another for progressive cavity molding, applying a barrier layer (e.g. oxygen scrubbing agent, etc.).
It would also be advantageous to provide structure to support pre-molding operations such as conditioning of the mold or molding inserts (e.g. heat and/or cool molding surfaces, apply a mold release agent, clean molding inserts and vents using dry-ice cleaning, etc.). All such operations would require additional structure coupleable to the injection molding machine to perform one or more of these operations. Such structure would be embodied as an operative structure or tooling that is mounted to a generic transport structure for movement of the operative structure into and out-of the molding region to perform their respective functions. However, all such additional structure will add complexity, weight, maintenance requirements, and degrade injection molding cycle time.
For example, U.S. Pat. Nos. 4,976,603; 5,518,387; and 5,709,833 disclose a so-called Servo Swing Chute (“SSC†) structure whereby parts are removed from mold cavities by tooling that is mounted to a swing arm transport structure so as to swing toward and away from the mold to remove the just-molded plastic articles from the mold cavities. These SWC structures are typically mounted outboard of the mold cavities. The operation of these swinging tools requires relatively more time to extract the molded parts thereby increasing the cycle time (i.e., additional time required to open the mold wide enough to permit the large swing radius dictated by either the swing arm and/or the molded article thereon).
The so-called side-entry robot/end-of-tool-arm (“EOAT†) mechanism is another variety of transport structure for moving tooling across the face of the mold to perform certain post-mold operations. Such transport structure and tooling are situated outboard of the molds, typically adjacent the injection molding machine with the attendant size and weight disadvantages inherent in the fact that the tooling is of a size required to service an entire mold face (i.e., the tooling must reach across the entire face of the mold) and has a robust and relatively massive structure to accommodate the tooling over a relatively long translation stroke.
U.S. Pat. No. 5,527,173 discloses a molding apparatus including operative structure in the form of a carrier plate for receiving molded articles and holding inserts to be incorporated into the molded article, and further for transferring the inserts to the mold cores prior to molding. The carrier plate is intended for use mounted to a typical side-entry robot.
U.S. Pat. No. RE 33,237 discloses an improved carrier plate cooperating with an injection molding machine for handling hollow plastic articles from the molding cavities. Further, the structure and operation of the side-entry robot is contemplated, suggested configurations including a platen-mounted robot with pneumatically or servo driven tooling plate actuation, and with the further provision of a carrier plate to a mold alignment device.
U.S. Pat. Nos. 4,616,992, 4,679,997, and 4,784,592 are examples of known devices for placing labels in the blow molds of a blow-molding machine. The devices include a transfer assembly mounted on a side-entry robot that uses vacuum cups or grippers to transport the labels and/or blown article. However, these patents fail to disclose a sliding transport structure that can be advantageously mounted inboard of the mold.
U.S. Pat. No. 5,520,876 discloses a process and a device for injection molding plastic cups having a label-shaped enveloping sheet integrated therein. The label holder and handling device are of an integral construction, pivotably connected to the mold core half. This patents fails to disclose a sliding transport structure that can be advantageously mounted inboard of the mold.
U.S. Pat. Nos. 4,351,630 and 4,340,352 disclose a device for the in-mold closing of a lid of a cap. The device includes a finger mounted inboard of the mold which slides between the mold sections in an open position, and in the process, engages a portion of the article or the lid, rotates the portion or lid about the hinge, and snaps the lid shut. This patents fails to disclose a sliding transport structure that can be compactly mounted inboard of the mold.
Commonly assigned U.S. patent application Ser. No. 10/243,002, filed 13 Sep. 2002, and entitled “APPARATUS FOR CLOSING A HINGED MOLDED PART†, discloses an apparatus and method for part removal from a mold and for the in-mold folding of a hinged molded part using a swing arm mechanism. This application does not, however, disclose a sliding transport structure that can be advantageously mounted inboard of the mold.
Thus, what is needed is a new transport structure and related tooling and/or method for performing various post-mold operations on just-molded plastic articles, which can reduce cycle time, reduce size and weight constraints, and offer great flexibility in the types of post-mold operations which can be carried out.
It is an advantage of the present invention to provide a side shuttle apparatus configured to be mounted inboard of a mold, and capable of translating across a mold face in order to position tooling thereon with respect to mold cavities/cores (or an auxiliary station (e.g. drop chute)) to perform various pre and post-mold operations, and a method of using such an apparatus, which overcomes the problems of prior art injection molding machines. The term “side†is not limiting as to the direction of movement of the shuttle structure. That is, the shuttle structure may move horizontally in horizontally-disposed molds, or may move vertically in vertically-disposed molds. Thus, the shuttle structure will move in a direction substantially parallel with the coplanar surfaces of the mold cavity and mold core faces.
According to a first aspect of the present invention, molding machine side shuttle structure and/or steps are provided whereby a shuttle plate has a portion always disposed inboard of a perimeter of a first mold half of the molding machine. A drive structure is configured to drive the shuttle plate only in one plane across a molding face of the first mold half. A plurality of gripping structures are coupled to the shuttle plate and are respectively configured to remove a corresponding plurality of molded articles from a corresponding plurality of mold cavities. The drive structure is configured to drive the shuttle plate to cause the plurality of gripping structures to be moved in a direction which is diagonal with respect to an array direction of the plurality of mold cavities
According to a second aspect of the present invention, structure and/or steps are provided whereby a molded article removal apparatus includes a plate coupled to a first mold half of a molding machine and having a portion always disposed inboard of a perimeter of the first mold half. The plate includes a removal device that is configured to grasp the molded article from at least one of a mold core and a mold cavity. Drive structure is configured to be coupled to the plate, and is configured to drive the plate (i) such that the plate is driven simultaneously in two orthogonal coplanar linear directions, and (ii) such that the removal device removes the molded article from the at least one of the mold core and the mold cavity.
According to a third aspect of the present invention, structure and/or steps are provided whereby molded article removal apparatus includes a first shuttle plate configured to be coupled to a mold portion, and includes a first plurality of molded article gripping devices that are configured to remove a corresponding first plurality of molded articles from one of (i) a first plurality mold cores and (ii) a first plurality of mold cavities. A second shuttle plate is configured to be coupled to the mold portion, and includes a second plurality of molded article gripping devices that are configured to remove a corresponding second plurality of molded articles from one of (i) a second plurality mold cores and (ii) a second plurality of mold cavities. Drive structure is configured to be coupled to the mold portion, and is configured to drive the first and second plates in opposite directions, each opposite direction being diagonal to an array direction of one of (i) the first plurality mold cores and (ii) the first plurality of mold cavities.
According to a fourth aspect of the present invention, structure and/or steps are provided whereby a method of removing a plurality of molded articles from one of (i) an array of mold cavities, and (ii) an array of mold cores, includes the steps of: (a) driving a shuttle plate in between a mold core half and a mold cavity half to a position where a plurality of grippers coupled to the shuttle plate may remove the plurality of molded articles from the one of (i) the array of mold cavities, and (ii) the array of mold cores; (b) using the grippers to grip the molded articles and remove them from the one of (i) the array of mold cavities, and (ii) the array of mold cores; and (c) driving the shuttle plate in a direction diagonal to an array direction of the one of (i) the array of mold cavities, and (ii) the array of mold cores, to a substantially co-linear position over a single drop chute.
The advantageous structure and/or function according to the present invention will be more easily understood from the following detailed description of the preferred embodiments and the appended Drawings, as follows.
1. Introduction
The present invention will now be described with respect to embodiments in which a plastic injection molding machine includes a mold with an inboard-mounted side shuttle for numerous in-mold operations including finished molded article handling. These molding operations could be carried out in single face molds, stack molds, three and four level molds, etc. Indeed the present invention may find applicability in the molding operations in other kinds of molding such as stamping, die-cast, metal molding, etc., or anywhere efficient molded-part handling structures would be beneficial.
As a brief overview to assist in understanding the following detailed disclosure, the preferred embodiments include a shuttle plate connected to a first mold half by a guidance assembly for guiding the shuttle plate linearly across the molding face of the first mold half. The shuttle plate is driven by an appropriate motive means. The shuttle plate includes operations structure which can carry out various operations on the just-molded parts while those parts are still present in their respective cavities or on their respective mold cores, or operations on the mold cavities or cores before or after the liquid plastic has been injected into the cavities. For example, the shuttle plate could include suction cups which are used to extract the molded part from its mold core, move the molded part linearly, and drop the part into a drop chute. Likewise, the operations structure can insert a label into the mold cavity before the plastic is injected therein, and/or close the lid of a molded article that is resident on the mold core.
The shuttle plate is preferably disposed inboard of the mold half so that a small machine footprint is provided, and the shuttle plate may have a shorter distance to move. This results in a lighter weight and compact design that can be operated more quickly and hence reduces cycle time.
The servo side shuttle (“SSS†) is configured to translate its tooling across the face of the mold (i.e. linear motion). The preferred in-board installation and related short stroke of the servo side shuttle provides for a compact and relatively light-weight design that again permits faster cycling and/or permits handling of higher cavitation molds at a lower cost relative to SSC and side-entry robot/EOAT (End Of Arm Tools) tools. Further, the preferred inboard side shuttle installation provides for improved tooling-to-mold cavity alignment for the sake of part handling and/or work-piece inserting (i.e. no losses due to robot-to-machine and/or mold-to-machine alignment).
Three embodiments of the present invention will now be described with respect to
2. The Structure of the Molded Article Handling Tooling
Shuttle plates 214 and 216 are disposed, respectively, on the left side and right side of the core plate 202. Each shuttle plate has four arms configured to extend over and cover corresponding ones of the cores 206. For illustration purposes only, the left side of
Servo motors 218 and 220 respectively drive the shuttle plates 214 and 216 through respective drive shafts 222,224, and rack/linear rails 226,228 and 230,232. The servo motors 218 and 220, the drive shafts 222,224, and the rack/linear rails 226,228 and 230,232 are preferably coupled to the core plate and/or the cavity plate. Each rack/linear rail preferably includes one or more linear bearings 234, and is configured and disposed to guide the shuttle plate with a linear motion with respect to a mold surface of the core plate. Of course, any convenient drive/guidance structure may be adapted for use in driving the shuttle plates.
Each shuttle is driven linearly across the face of the core plate (and/or the cavity plate) between the inboard/open position (also called the pick position) where it picks the molded article from the core, and an outboard or open position (also called the drop position) where it drops the molded articles into drop chutes 236 and 238. In
The shuttle plates 214 and 216 are driven by the servomotors 218 and 222 to move linearly between the cores 206 and the drop chutes 236,238. Once positioned in the drop chutes, a vacuum is released and/or an interfering tab is disposed to drop the parts 240 into the drop chutes. Drive gears 320 are used to transmit the motion from drive shafts 222,224 to the rack/linear rails 226,228 and 230,232, respectively. In
In more detail, the cavity plate 302 includes sixteen cavities 304 and four drop chutes (only the drop chutes 1302 and 1304 are shown for clarity). Four shuttle plates are provided (again, only the shuttle plates 1306 and 1308 are shown for clarity), one shuttle plate for each column of cavities. Servo motor 218 drives both of the shuttle plates 1306,1308 through the drive shaft 222, the rack/linear rails 226,228, and the gears 320. The shuttle plates 1306,1308 are driven simultaneously in the direction of the black arrows C to drop the parts 240 into the two corresponding drop chutes. In a similar fashion, an unshown servo motor moves the other two shuttle plates in the direction of arrows D to drop the parts 240 into the drop chutes 1302,1304.
A drive structure (to be described in more detail below) is used to drive the shuttle plates 1602, 1604 while the shuttle plates hold onto the removed row of molded articles. The shuttle plates are driven only in one plane across a molding face of the first mold half and along a direction (arrows F) that is diagonally aligned with respect to the alignment of the row of mold cavities 304 over to a respective molded article drop off position included in a single drop chute 1606. The driving may be accomplished by one or more stepped diagonal motions, or sequential orthogonal motions, or a combination of these motions. In the drop off position, the molded articles 240 are in position to be released from the shuttle plates 1602,1604 so that when released, the molded articles drop down a drop-off chute 1606. The technical effect of this arrangement is to permit usage of an aligned drop off chute 1606 versus dropping off many adjacent rows of parts 240 in to many drop-off chutes as shown in
The drive structure that performs this diagonal motion is accomplished by the servo motors 1608 and 1610 that drive respective helical/screw drive shafts 1612 and 1614, either simultaneously or sequentially, or in a stepped fashion as needed. In the preferred embodiment, the drive screw shaft 1612 engages a drive nut 1630 upon which is mounted an arm 1631 that connects to the shuttle plate 1602 such that when the shaft 1612 rotates in a first direction, the drive nut 1630 moves the arm 1631 and the plate 1602 in the direction of arrow G (vertically downward in the drawing). Simultaneously, the rotation of screw shaft 1612 also drives rack/linear rails 1632, 1633, as previously described, so that the rack moves in the direction of arrow H (horizontally in the drawing). A vertical rod 1634 is fastened to the end of the two rails 1632, 1633 and passes through bearings 1635 that are mounted on the shuttle plate 1602. The pitch of the screw 1612 and nut 1630, and the gear ratio of the gear/rack drive are selected so that upon rotation of shaft 1612 their combined actions cause shuttle plate 1602 to move along an appropriately angled path (arrow F) to cause the part 240 to be moved from its ejected position adjacent the core to its drop position aligned with the drop chute 1606 and between adjacent parts from other cores. Reversing the direction of rotation of shaft 1612 causes the shuttle plate 1602 to return from the drop position to the pick up position. Servo motor 1610 drives shaft 1614 to move shuttle plate 1604 on the opposed side of the mold in a complementary manner.
3. The Structure of the Lid-Closing Tooling
In
In alternative #2 of
4. The Structure of the In-Mold Labeling Tooling
In the present embodiment, the work piece comprises a label which will be affixed to the outside of the molded plastic container in a manner described below. However, the work piece may comprise other materials such as a container lid, a molded insert, a temperature sensitive element, electronic circuitry, batteries, filter element, diaphragm, etc., or any other device which may be useful in the finished product. The work piece receptacle 2108 preferably includes four vacuum ports (not shown) which are used to retain the labels in the receptacle. The work piece may be inserted into the mold cavity (or core) before the injection step, after the injection step, or in between injections of different layers (or other structure) of the molded article.
In summary, the stripper ring 208 moves the floating plates 2106a, 2106b downwardly as it ejects the parts 240 until the lower floating plate 2106b reaches the bottom of the mold and the labels 2310 held by the suction cups 2309 can be transferred to the mold at the same time as the previously molded parts 240 are transferred to the suction cups 2308. When the floating plates 2106a, 2106b are back in the home position, the main shuttle 2102 is retracted from the mold and the parts 240 are discharged into the drop chute and labels 2310 are loaded onto the suction cups 2309 to prepare the shuttle for the next cycle.
5. The Operation
The operation of the various structures according to the present invention has been described above. The overall operation of one molding operation according to the preferred embodiments proceeds as outlined below.
Steps:
1. Inject molten plastic into the mold cavity;
2. Open mold;
- 2.1. Move shuttle to the pickup position;
- 2.2. Part ejection/transfer to side shuttle tooling;
- 2.2.1. (optional) Work piece (e.g. label) transfer;
- 2.2.2. (optional) Intermediate mold full or partial closings to effect transfers/operations;
- 2.3. Move shuttle to the drop position, which may be the same or different from the parked position;
3. Close mold;
- 3.1. Strip the part from the side shuttle tooling; and
- 3.2. (optional) work piece (e.g. label) pickup.
6. Advantageous Features
The servo side shuttle system offers gains in a reduction in cycle time, an increase in mold cavities able to be serviced, reduced capital investment, and improved positional accuracy. Specifically:
(1) In-mold handling/labeling of molded articles requires less time since the shuttle plate is inboard of the mold, and hence has a shorter distance to travel than a robot plate that must completely exit the molding area. Further reduction of cycle time is possible where a multiplicity of servo side shuttles is provided on a single mold face (e.g. total horizontal travel is divided by two by having left and right side shuttles).
(2) The inboard handling of molded articles between their molding cavities and the drop chutes with the servo side shuttle is a substantially linear motion and has a reduced mold opening stroke requirement relative to inboard part handling with servo swing chutes wherein the articles are handled through a large arc and hence more space between the mold halves is required.
(3) By example, an 8.5″ lid would require an opening stroke in excess of the 10-12″ rotational arc to swing the part with a conventional swing chute whereas for the same part, the SSS would require only 2-3″ of stroke, and thereby provide a dramatic cycle time savings from the reduced time required for mold stroking.
(4) By harnessing the movement of the mold stripper plate/ejection mechanism on the core side to interact with the shuttle plate to transfer the work piece into the mold eliminates an actuator and related controller feedback and thereby saves on cost and weight, the weight savings and controller simplification (no signal delay time for tooling plate actuator) provides potential cycle time savings.
(5) Known in-mold labeling systems are considered limited to servicing cavitations of 2×4 due to the size, weight, positional accuracy, and related stability of the robot arm, whereas the servo side shuttle is able to handle cavitations of 2×8 or higher due to a stable in-mold installation, and a lighter and more compact construction enabled by the shorter stroke distance, shuttle weight (i.e. no onboard actuators). Further, typical standalone in-mold labeling systems lose precision due to relative movements of robot/machine/mold, whereas the present invention contemplates inboard mounting (i.e. fastening everything to the mold) for improved operating accuracy.
(6) The technology is not limited to in-mold labeling, but may have more generic use for introducing inserts into the molding cavity or into the molded or partially molded article.
(7) The method of operating the side shuttle wherein the molded articles are handled from the molding cavity to the drop chute preserves the orientation of the molded article that may be advantageous for post-molding operations such as stacking/packaging. Further, the inboard installation of the side shuttle and its inherent alignment accuracy provides for the accurate orientation and placement of molding inserts such as labels.
7. Conclusion
Thus, what has been described is a servo side shuttle apparatus and method capable of providing a wide array of operations on in-mold articles, which will greatly reduce the cycle time and cost of producing molded parts.
The individual components shown in outline or designated by blocks in the attached Drawings are all well-known in the molding arts, and their specific construction and operation are not critical to the operation or best mode for carrying out the invention.
While the present invention has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
Any U.S. and foreign patent document discussed above is hereby incorporated by reference into the Detailed Description of the Preferred Embodiment.