The present invention generally relates to molding machines, and more specifically the present invention relates to a molded article handling device usable with complementary mold halves of a molding machine.
The device 100 includes a stripper plate 102, a left-side slide bar 104, a right-side slide bar 106, a left-side mold portion 108, a right-side mold portion 110, a left-side connecting bar 114, a right-side connecting bar 112, a cam follower 116 and a cam 118.
The mold portions 108 and 110 mold, in cooperation with the complementary mold halves, the molded article. The complementary mold halves include a first mold half and a second mold half. The mold portions 108 and 110 are connected to the slide bars 104 and 106 respectively. The mold portions 108 and 110 include a cooling circuit for cooling the molded article after it is molded. The stripper plate 102 faces the first mold half while the slide bars 104 and 106 face the second mold half.
The stripper plate 102 is made to reciprocate between the complementary mold halves by an actuator (not depicted) along an axis that extends between the complementary mold halves. The axis extends along a clamping direction that the complementary mold halves reciprocate therealong. The slide bars 104 and 106 are slidably mounted to the stripper plate 102. The bars 104 and 106 are made to reciprocate along a direction that extends orthogonal to the axis extending between complementary mold halves.
The connecting bars 114 and 112 are connected to the slide bars 104 and 106 respectively. The cam follower 116 is connected to the connecting bar 114. Another cam follower (not depicted) is connected to the connecting bar 112. The cam follower 116 follows within a cam pathway defined by the cam 118, which is fastened (in effect) to the first mold half. When the stripper plate 102 is actuated to move by a hydraulic actuator (not depicted) along the axis extending between the complementary mold halves and away from the first mold half, the cam follower 116 is made to move along the cam pathway defined in the cam 118 and in this manner the slide bar 104 is moved perpendicular to the axis that extends between the complementary mold halves. The cam pathway is also called a cam profile. Disadvantageously, the problem is in establishing a suitable cam profile and/or changing the cam profile based upon changes made to a molding machine processing approach (such as, for example, increasing the cycle time of the molding machine).
U.S. Pat. No. 6,799,962 (Assignee: Husky Injection Molding Systems Limited; Inventor: Mai et al) discloses a stripper assembly for an injection molding machine comprising at least one slide pair having a first slide and a second slide and actuation means operatively coupled to said first slide for moving the first slide in a first direction. According to an important aspect of the invention, the stripper assembly further comprises transmission means operatively coupled to said first slide and said second slide for transforming the movement of the first slide in the first direction in a movement of the second slide in a second direction, the second direction being opposite to the first direction.
U.S. Pat. No. 5,531,588 (Assignee: Electra Form; Inventor: Brun et al) discloses an adjustable cam track for an injection molding machine includes a set of guides coupled to a moveable platen for guiding the movement of space defining surfaces which are movably mounted to a stripper platen as it moves with respect to the movable platen. A set of cam followers coupled to the space defining surfaces cause relative movement of each pair of surfaces to release molded articles previously striped from the molds of the molding machine. A set of cam inserts engage the cam followers and are adjustably positionable with respect to the guides to adjust the point of release of the molded articles. Each guide includes a pair of guide walls forming a channel defining two limits of position of the cam follower engaged therein. Each cam insert is received between the guide walls and includes a pair of cam insert walls spaced apart by a distance about equal to the size of the cam follower engaged therein to define a path of movement for the cam follower between the two limits of position. Each cam insert includes a first toothed rack, while a second toothed rack is removably fixed to each guide and engages the first toothed rack to fix the position of each cam insert relative to each guide only at certain preselected locations to coordinate the operation of all the cam followers thereby avoiding any wear imbalance.
U.S. Pat. No. 5,653,934 (Assignee: Electra Form; Inventor: Brun et al) discloses a molding machine including a mold for molding articles of plastic in the molding machine and apparatus for removing the molded articles from the molding machine. The mold includes molding elements movable by the molding machine in a first dimension between a closed conformation where the molding elements define cavities in which the articles are molded and an open conformation where the molding elements are separated from each other by a distance sufficient to permit release of the molded articles in a space between the molding elements. A first molding element includes channels situated on opposite sides of the molded articles for receiving the article removing apparatus while the molding elements are in the closed conformation. A cam track is fixed to the first molding element and a cam coupled to article holders is engaged in the cam track to move the article holders elements from a position aligned with the channels toward engagement with the molded articles as the molding elements open. A boom is coupled to the second molding elements and a trolley is coupled for linear movement along the boom, the article engaging elements being coupled to the trolley for movement out of the molding machine when it is open and into the channels when the molding machine is closed.
U.S. Pat. Nos. 6,799,962, 5,531,588 and 5,653,934 use cams, cam tracks and cam followers to move a stripper plate between a mold opened position and a mold closed position, and the stripper plate is not stoppable between these positions.
Patent WO 2004/068927 A2 (Assignee: Otto Hofstetter AG) attempts to overcome problems associated with the cam 118 by teaching the use of a hydraulic actuator as a replacement for the cam 118 and cam follower 116. The hydraulic actuator is used for shuttling (moving, translating) the slide bar 104. Disadvantageously, it appears that the degree or the amount of displacement of the slide bar 104 may not be suitably controlled by use of the hydraulic actuator. The hydraulic actuator is stroked between its end terminus “stroking” points (that is, points located between an opened position and a closed position).
According to the inventors, it is believed that it is difficult to control a degree of stroke of the Hofstetter hydraulic actuator (that is, it is not possible to stroke the hydraulic actuator to selected or selectable points located between two terminus travel points of the actuator). In other words, the Hofstetter hydraulic actuator includes and arm that is stroked between travel endpoints but does not have the ability to stop, start or vary the speed of motion at any of point between the travel end points. Hofstetter teaches: “The base plate 2 features an inclined pulling element 7 on the side, stepped at point C only to create a release stroke “h”. The release stroke “h” serves only to loosen the preforms from the male mold cones 5, to make sure the preforms will not remain sticking on these cones when the latter are fully opened. The base plate (2) features an inclined pulling element (7) that actuates the slide (4) in a way as to opening the male mold cones (5, 5′) at a certain point (C) between its closed (A) and removal (B) positions only by a slight release stroke (h) to prevent the preforms from sticking.” Therefore, in effect, Hofstetter limits the number of positions between end travel points to one point or one position. Also, it is believed that uncontrolled stroking of the Hofstetter hydraulic actuator may permit a slide bar to accidentally nick or blemish the molded article upon retraction of the molded article from the complementary mold halves. The problem, which is not resolved by Hofstetter, is resolved by the present invention by providing a slide bar that is configured to be actuated upon by an actuator, in which the actuator is configured to move the slide bar towards selectable positions with varying speeds and optional intermediate stops, in which the selectable positions are located between travel terminus points. Hofstetter does not contemplate more than one “h”. The purpose of implementing the “h” is to permit improved or easier releasing the preform from the surrounding structure and nothing more than that.
The technical effect realized by the embodiments of the present invention and variations and alternatives thereof is the ease with which to reconfigure a preferred preform removal path so that a side bar does not accidentally nick or blemish a preform while the preform is retracted from complementary mold halves. This arrangement also reduces development time associated with configuring cams for use with the slide bar. Another advantage of some embodiments is changes in the preform removal pathway may be enabled in a convenient manner without physical alteration to the mold structure after it has been built. Advantageously, the present invention permits the establishment of a suitable cam profile and/or changing the cam profile based upon changes made to a molding machine processing approach (such as, for example, increasing the cycle time of the molding machine).
In a first aspect of the present invention, there is provided a molded article handling device, including a slide bar configured to have a mold portion configured to mold, in cooperation with complementary mold halves of a molding machine, a molded article, and the slide bar is also configured to be actuatable by an actuator, the actuator configured to move the slide bar towards selectable positions, the selectable positions located between travel terminus points.
In a second aspect of the present invention, there is provided an apparatus, including complementary mold halves of a molding machine, and also including a molded article handling device, the molded article handling device including a slide bar configured to have a mold portion configured to mold, in cooperation with the complementary mold halves, a molded article, and the slide bar is also configured to be actuatable by an actuator, the actuator configured to move the slide bar towards selectable positions located between end-travel terminus points.
In a third aspect of the present invention, there is provided a system, including a molding machine, the system also includes complementary mold halves cooperating with the molding machine, and the system also includes a molded article handling device, the molded article handling device including a slide bar configured to have a mold portion configured to mold, in cooperation with the complementary mold halves, a molded article, and the slide bar is also configured to be actuatable by an actuator, the actuator configured to move the slide bar towards selectable positions located between end-travel terminus points.
A better understanding of the exemplary embodiments of the present invention (including alternatives and/or variations thereof) may be obtained with reference to the detailed description of the exemplary embodiments along with the following drawings, in which:
Generally, the device 200 (according to the preferred embodiment) includes a left-side slide bar 204 (hereinafter referred to as the “slide bar” 204) and a left-side mold portion 208 (hereinafter referred to as the “mold portion” 208) that is fixedly attached to the slide bar 204. The mold portion 208 is used to mold, in cooperation with complementary mold halves (not depicted) of a molding machine (not depicted), a molded article (not depicted). The mold portion 208 includes a cooling mechanism that carries a coolant that cools a portion of the molded article. In other embodiments, the slide bar 204 is connected to a plurality of mold portions (not depicted) that are similar to the mold portion 208.
The device 200 also includes an actuator 216. The slide bar 204 is configured to be actuated upon by the actuator 216. The actuator 216, which is for example an electric servo motor drive or the like, when so energized moves the slide bar 204 towards selectable or selectable positions, in which the selectable positions are located between travel “end” terminus points of the actuator 216. A figure is not provided for illustrating an alternative variation in which the actuator 216 is connected directly to the slide bar 204. In a preferred variation, the actuator 216 is connected to either one of the connecting bars 212 or 214 so that a plurality of slide bars (not depicted) are connected to the connecting bars 212 and 214, and the complementary mold halves mold a matrix of preforms that need to be removed by the plurality of slide bars when so actuated to be moved by the actuator 216.
Specifically, the actuator 216 shuttles the slide bar 204 and the molded portion 208 away from the molded article as the molded article is ejected from the complementary mold halves. The actuator 216 is a replacement of the cam 118 and the cam follower 116 both depicted in
According to an alternative embodiment, the device 200 also includes a stripper plate 202, a right-side slide bar 206 (hereinafter referred to as the “slide bar” 206), a right-side mold portion 210 (hereinafter referred to as the “mold portion” 210), and a right-side connecting bar 212 (hereinafter referred to as the “connecting bar” 212).
The mold portions 208 and 210 mold, in cooperation with the complementary mold halves, the molded article. The mold portions 208 and 210 are connected to the slide bars 204 and 206 respectively. The mold portions 208 and 210 contain a cooling circuit (not depicted) for cooling the molded article after it is molded. The slide bars 204 and 206 are movable, by way of the stripper plate 202, along an axis (not depicted) that extends between the complementary mold halves. The slide bars 204 and 206 are movable along a direction (not depicted) that extends orthogonal to the axis extending between the complementary mold halves. Preferably, the connecting bars 214 and 212 are connected to the slide bars 204 and 206 respectively. Another actuator (not depicted) is connected to the connecting bar 212.
When the stripper plate 202 is actuated to move by a hydraulic actuator or other mechanism (not depicted) along an axis extending between the complementary mold halves, the actuator 216 moves the slide bar 204 along the direction that extends orthogonal to that axis.
The actuator 216 urges the connecting bar 214 to move, which in turn moves the slide bar 204 that shuttles or moves the mold portion 208 (which is attached to the slide bar 204).
In a first variation, the actuator 216 is mounted to the stripper plate 202. Lateral (side to side) motion of the slide bars 204 and 206 and front-to-back motion of the stripper plate 202 are independently controllable by separate actuators.
In a second variation, the actuator 216 is controlled by a built-in central processing unit (not depicted) or micro controller device, which is then controlled by a supervisory data processing system and/or a programmable logic controller, and any combination and permutation thereof.
In a third variation, the actuator 216 is controlled with a built-in logic chip, which is programmed or controlled/programmed by way of physical switches that are toggled to a selectable binary state that reflects a desired travel path for the slide bar 204.
In an alternative embodiment, the device 200 is configured as a tool for designing a cam shape of a cam, for testing new preform extraction profiles for a proposed cam, and/or for researching and identifying cam profiles (that is, a preferred preform extraction profile shape for selected types of preforms). The advantage associated with the alternative embodiments is reduction of design time and cost associated with identifying cam profiles used in the cam 118 of
In an alternative, the molded article 308 is a preform. In another alternative embodiment, the molded article 308 is a polyethylene terephthalate (PET) preform.
The instructions S600 include operation S602 to operation S632, which are as follows:
Operation S602 includes starting a molded article removal or ejection cycle.
Operation S604 includes reading a stripper plate sensor (not depicted) that provides a relative position of the stripper plate 202. The stripper plate sensor can be mounted in a convenient location. The relative position of the stripper plate 202 is a position relative to an arbitrarily selected origin.
Operation S608 includes reading a slide bar position sensor (not depicted) that provides a relative position of the slide bar 204. The slide bar position sensor can be mounted in a convenient location. The relative position of the slide bar 204 is a position relative to an arbitrarily selected origin.
Operation S610 includes determining whether the slide bar 204 and the stripper plate 202 are currently positioned at an origin (that is, the origin is a first row of the look-up table 506). If they are located at the origin, then control is transferred over to operation S614. If they are not located at the origin, the control is transferred over to operation S612.
Operation S612 includes terminating operation S600 due to an error. The error is the stripper plate and slide bar are not located at the origin at the beginning of the removal cycle.
Operation S614 includes initiating forward movement of the stripper plate 202 away from the complementary mold half 304 and towards the complementary mold half 302 by actuating the actuators 314 and 316.
Operation S616 includes reading the stripper plate sensor to determine the relative position of the stripper plate 202 (that is, the relative position is a position relative to an arbitrarily selected origin).
Operation S618 includes locating a stripper plate position X-coordinate from the column 508 of the look-up table 506.
Operation S620 includes determining whether the stripper plate 202 is located at a full stroke position (that is, the stripper plate 202 is located close to the complementary mold half 302). If the stripper plate 202 is located at the full stroke, then operation is transferred over to operation S630. If the stripper plate 202 is not located at the full stroke position, then control is transferred over to operation S622.
Operation S622 includes selecting a corresponding Y-coordinate (from the column 510 of the look-up table 506) in which the corresponding Y-coordinate is the Y-coordinate closest to the located stripper plate position X-coordinate (as determined above).
Operation S624 includes reading the slide bar sensor to determine the current position of the slide bar 204.
Operation S626 includes generating a correction signal based on the selected Y-coordinate and most recently-read slide bar position.
Operation S628 includes sending a correction signal to the slide bar actuator 216, and the actuator 216 responds accordingly, and then control is transferred over to operation S616 and the control logic is re-iterated.
Operation S630 includes stopping forward movement of the stripper plate 202.
Operation S632 includes ending the molded article removal cycle.
In an alternative, the programmed instructions direct the DPS 320 to control the actuator 216 responsive to selectable relative positions of the slide bar 204 and selectable relative positions of the stripper plate 202.
In another alternative, the programmed instructions direct the DPS 320 to control the actuator 216 responsive to determined relative positions of the slide bar 204 and of the stripper plate 202 compared against selectable relative positions of the slide bar 204 and selectable relative positions of the stripper plate 202.
The instructions S700 include operations S702 to S726, as follows:
Operation S702 includes starting a reset cycle.
Operation S704 includes initiating reverse movement of the stripper plate 202 by way of energizing the actuators 314 and 316.
Operation S706 includes reading the stripper plate sensor.
Operation S708 includes comparing the stripper plate position as provided by the sensor to values in the column 508 of the look-up table 506
Operation S710 includes determining whether the stripper plate 202 is currently located at the origin. If the stripper plate is not currently located at the origin, the control is transferred over to operation S706. If the stripper plate 202 is currently located at the origin, then control is transferred over to operation S712.
Operation S712 includes stopping actuation of the stripper plate 202.
Operation S714 includes initiating reverse movement of the slide bar 204.
Operation S718 includes reading the slide bar sensor.
Operation S720 includes comparing the currently determined slide bar relative position to the column 510 of the look-up table 506.
Operation S722 includes determining whether the slide bar 204 is currently positioned at the origin. If the slide bar 204 is not currently located at the origin, the control is transferred over to operation S718. If the slide bar 204 is currently located at the origin, then control is transferred over to operation S724.
Operation S724 includes stopping actuation of the slide bar 204.
Operation S726 includes ending the reset cycle.
The concepts described above may be adapted for specific conditions and/or functions, and may be further extended to a variety of other applications that are within the scope of the present invention. Having thus described the exemplary embodiments, it will be apparent that modifications and enhancements are possible without departing from the concepts as described. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims: