Cooling device for molded articles

A rotatable turret block is mounted on an index molding machine. The turret block includes at least one mold core for forming molded articles thereon at least one face of the rotatable turret block. The molded articles are transferred from the mold cores to spaced track members for retention and cooling thereon, and the cooled molded articles removed from the track members.

BACKGROUND OF THE INVENTION 
 The present invention relates to a cooling device for use with an index 
 molding machine having a rotatable turret block mounted thereon. In 
 accordance with the present invention, a device and process is provided 
 for use with an index machine that may eject relatively thick walled parts
 during turret block rotation and provide means to capture and retain the 
 ejected parts so that they remain damage free and can continue to cool. 
 U.S. patent application Ser. No. 09/167,699, filed Oct. 7, 1998, and U.S. 
 Pat. No. 5,837,301, issued Nov. 17, 1998, both to the assignee of the 
 present invention, both show fast cycling machines that use only two faces
 of a turret block for mounting mold halves. The device in the aforesaid 
 patent application utilizes a robot to cool and remove the parts from the 
 mold to provide extended cooling time and prevention of damage to the 
 preform during post mold cooling. The device shown in the '301 patent 
 teaches the concept of ejecting parts during the 180 degree rotation of 
 the turret block when only two mold core sets are used. This teaching 
 assumes that the parts are relatively thin and are sufficiently cooled on 
 the mold cores to allow damage free ejection. Also, as the parts are 
 ejected they fall randomly to a conveying system beneath the turret block.
 U.S. patent application Ser. No. 60/094,793, filed Jul. 31, 1998, also to 
 the assignee of the present invention, teaches ejecting parts from cooling
 tubes mounted on a robot take out plate wherein the parts fall into a 
 fixture that continues cooling them and opens to allow the parts to fall 
 through to a conveyor beneath. 
 It would be highly desirable to minimize cycle time by ejecting 
 comparatively thick parts, especially during turret block rotation, 
 without risking part damage and providing post mold cooling options. 
 Accordingly, it is a principal object of the present invention to provide a
 cooling device and method for use with an index molding machine which 
 minimizes cycle time by ejecting comparatively thick parts. 
 It is a further object of the present invention to provide a device and 
 method as aforesaid which may eject parts during turret block rotation and
 without risking damage to the part. 
 Further objects and advantages of the present invention will appear 
 hereinbelow. 
 SUMMARY OF THE INVENTION 
 In accordance with the present invention, the foregoing objects and 
 advantages are readily obtained. 
 The present invention provides a cooling device for use with an index 
 molding machine having a rotatable turret block mounted thereon and having
 at least one and generally a plurality of mold cores for forming molded 
 articles thereon on at least one and desirably two faces of said rotatable
 turret. The device includes track means having spaced track members 
 adjacent the rotatable turret block means for transferring the molded 
 articles from the mold cores to the spaced track members for retention and
 cooling thereon, and means for removing the cooled molded articles from 
 the spaced track means. The mold core is engagable with a mold cavity for 
 forming the molded articles in the mold cavity. The mold core is rotated 
 with the molded articles thereon to position the molded articles above the
 spaced track members for transfer of the molded articles from the mold 
 core to the track means, desirably during movement of the rotatable 
 turret. 
 The process of the present invention for cooling the molded parts 
 comprises: providing an index molding machine having a rotatable turret 
 block mounted thereon and having at least one mold core for forming molded
 articles thereon on at least one face of the rotatable turret; positioning
 track means having spaced track members thereof adjacent the rotatable 
 turret block; transferring the molded articles from the mold core to the 
 spaced track members for retention and cooling therein; and removing the 
 cooled molded articles from the spaced track members. 
 Further features of the present invention will appear hereinbelow.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
 Referring now to the drawings in detail there is shown in FIG. 1 an 
 elevational and schematic side view of a turret injection molding machine 
 used in the present invention, which is designated generally as 10. 
 Injection molding machine 10 generally includes a rotatable turret block 
 12 with a plurality of movable mold halves 14a-14d, a stationary mold half
 and platen 16 and injection unit 18, all positioned on base 20. 
 Injection molding machine 10 may be used for molding a variety of different
 types of articles and accordingly, is not limited for use with any 
 particular type of article. Preforms are referred to throughout this 
 description by way of example only. 
 While the turret block is shown throughout this description as rotatable on
 a horizontal axis, and this is the preferred embodiment, it is feasible 
 that a similar design of a movable turret block providing the clamping 
 action may be provided which is rotatable on a vertical axis. Accordingly,
 this invention is not considered limited to the horizontal axis feature. 
 As shown in FIGS. 1-5, turret block 12 is preferably longitudinally movable
 on base 20 via a set of rollers 22 attached to the bottom of the turret 
 block and thereby providing a mold clamp force. Base 20 includes hardened 
 ways 24 which engage rollers 22, wherein rollers 22 engage the underside 
 of ways 24 so as to counteract upward forces and tipping forces that may 
 act on the turret block assembly. Turret block 12 is rotatable as shown in
 FIGS. 1-5 by a motor, as an electric servo drive motor 26 and preferably 
 on a horizontal axis H through arcuate sectors as shown in FIGS. 1-5 of 
 substantially 90.degree.. Preferably, the electric servo drive motor 26 is
 connected via a belt drive 30 to axis H for rotating turret block 12, as 
 shown in FIG. 4, while the electric servo drive motor is preferably 
 mounted on one of turret block carriages 32a and 32b extending from base 
 20. 
 As shown in FIG. 5, turret block 12 includes a plurality of movable mold 
 halves, i.e. movable mold halves 14a-14d each of which includes a set of 
 mold cores 34a-34d, respectively, each set having at least one mold core, 
 adapted for engagement with a set of mold cavities 36, each set including 
 at least one mold cavity and located in stationary mold half and platen 
 16. As shown in FIGS. 1-5, four movable mold halves or faces 14a-14d are 
 provided on turret block 12, although any number supportable by the size 
 of the turret block 12 can be used. Sets of mold cores 34a-34d are adapted
 to be rotated into horizontal and vertical alignment with sets of mold 
 cavities 36. 
 Referring still to FIG. 5, turret block 12 includes sets of ejector pistons
 or stripper rings 38a-38d, and a system for the operation thereof, which 
 operate on sets of mold cores 34a-34d and strippers positioned on movable 
 mold halves 14a-14d, respectively. Accordingly, sets of ejector pistons or
 stripper rings 38a-38d are positioned within turret block 12 and parallel 
 to sets of mold cores 34a-34d and perform the function of stripping the 
 mold cores of finished molded articles, for example, preforms. Each 
 movable mold half and platen 14 includes at least one ejector piston in 
 each set 38a-38d for stripping finished articles from sets of mold cores 
 34a-34d. For the detailed design of the ejector piston or stripper ring 
 system for use with sets 38, reference is made to U.S. Pat. No. 5,383,780,
 issued Jun. 24, 1995, to the assignee of the present invention, for 
 incorporation by reference of a design of the ejector piston or stripper 
 ring system, particularly column 4, line 29, to column 7, line 6, and 
 FIGS. 1-8. Preferably, the ejector piston or stripper ring system is 
 actuated via the hydraulic services supplied to the turret block. The 
 hydraulically actuated ejector piston or stripper ring system actuated by 
 on board hydraulic services is the preferred design, however, other 
 designs may be used. 
 Turret block 12 is movable backward and forward along hardened ways 24 on 
 base 20 via piston/cylinder assemblies 40a-40d positioned in stationary 
 mold half and platen 16, as shown in FIG. 5. Preferably four 
 piston/cylinder assemblies 40a-40d, as shown in FIGS. 2, 3 and 5, are used
 which are positioned in the corners of stationary mold half or platen 16. 
 Each piston/cylinder assembly 40a-40d includes a piston 42a-42d (42a, 42c 
 and 42d not shown), which pistons 42a-42d are attached to tie bars 
 44a-44d, respectively, which tie bar acts as the piston shaft. 
 Accordingly, tie bars 44a-44d extend from the piston/cylinder assemblies 
 40a-40d and are connected at an opposite end to turret block 12. In order 
 to move turret block 12 backward and forward relative stationary mold half
 and platen 16, pressurized fluid is forced into cylinders 46a-46d against 
 pistons 42a-42d, respectively. The side of pistons 42a-42d in which 
 pressurized fluid is forced against, determines the direction in which 
 turret block 12 moves relative stationary mold half and platen 16, that 
 is, either into an open or closed position, shown in FIGS. 2 and 5, 
 respectively. Tie bars 44a-44d pass through the turret block carriages 32a
 and 32b and are attached thereto via retaining nuts 48a-48d, as shown in 
 FIG. 6, respectively. 
 Services S, shown schematically in FIGS. 3 and 4, are provided to turret 
 block 12 via a rotary union 50, also shown schematically. Accordingly, as 
 turret block 12 rotates, services S are continuously supplied to the 
 movable mold halves 14a-14d. Such services S include the supply of 
 electricity, pressurized fluid, cooling fluids, and hydraulic fluids, etc.
 For using these services, turret block 12 also includes the required 
 circuitry and control valves 51 (shown schematically) on board and movable
 and rotatable with the turret block. 
 Injection unit 18, preferably in the form of a reciprocating screw 
 injection unit, is connected with stationary mold half and platen 16 
 positioned on base 20 for providing melt to the mold cores for molding. 
 Injection unit 18 is preferably movable into and out of engagement with 
 stationary mold half and platen 16 by means of carriage cylinders (not 
 shown) on rollers and hardened ways, similar to as described above for use
 with turret block 12. If desired, injection molding machine 10 of the 
 present invention can provide co-injection of articles, for example, 
 preforms. For this arrangement, two conventional reciprocating screw 
 injection units are used to feed two different kinds of resins into 
 conventional mold cavities, such as those shown in stationary mold half 
 and platen 16, which mold half and platen 16 may include a two material 
 hot runner system which delivers both resins into each mold cavity within 
 stationary mold half and platen 16 for molding multi-layered articles, for
 example, preforms. 
 In accordance with the preferred embodiment of the present invention, a two
 faced turret block is rotated through 180 degrees during the combined 
 clamp open and close motions to present alternating mold cores to the mold
 cavity. A mechanical linkage creates the rotary motion using the clamp 
 opening and closing motions. A partial stroke position means may be 
 provided to allow the mold cores to clear the mold cavities before 
 rotation is permitted. 
 FIGS. 1-6 teach the basic principle of the turret machine in which the 
 carriage and turret block perform all the functions of a conventional 
 clamp, opening, closing and clamping the mold, ejecting the parts and 
 providing services to the mold's core halves. The same carriage and turret
 structure including the same linear motion means, tiebar clamping, part 
 ejection means and services provided may be incorporated in FIGS. 7-13 
 described schematically hereinbelow. 
 The preferred embodiments of the present invention are described 
 hereinbelow with reference to FIGS. 7-13. 
 FIGS. 7A and 8A show end views of rotatable turret block 60 carried on 
 journals between two carriers 62, 64 which slide on machine base 66 shown 
 schematically in FIG. 7A. Turret block 60 may be rotated by belt 68 driven
 by motor 70 in a manner shown in FIGS. 1-6. The turret block 60 is more 
 clearly shown in FIGS. 1-6 and is shown in FIG. 7A with one mold core half
 72 having multiple rows of cores 74, with one row of cores 74 shown in 
 FIG. 7A, shown passing through the "down" position with the cores 74 
 facing downwards. Beneath the rotatable turret block and beneath the cores
 is a track means 76 including a pair of spaced track members or rails 78, 
 80. Preforms 82 formed on cores 74 include an outwardly extending flange 
 84 (shown more clearly in FIG. 8A), and rails 78, 80 include spaced ledge 
 members 86, 88 (shown more clearly in FIG. 7B). In the closed position 
 shown in FIGS. 7A & 7B, the rails and ledge members are spaced closer 
 together than in the open position shown in FIGS. 8A & 8B so that they 
 form a supporting track for the outwardly extending flanges of the 
 preforms. Thus, in the closed position the rails 78, 80 retain preforms 82
 ejected from the passing mold cores 74. The preforms fall into the space 
 between the rails and are captured thereby. The flanges 84 of the preforms
 82 extend beyond the base diameter of the molded part so that the width of
 the track can be set to allow most of the part to pass between the rails 
 until the outwardly projecting flanges are blocked from further passage by
 the ledges 86, 88 of rails 78, 80 by virtue of the extended width of the 
 flanges, as clearly shown in FIGS. 7A & 7B. Thereby the preforms are held 
 between the rails separated from each other and they can be subjected to 
 further cooling for example from air blown by fans 90 if needed. As shown 
 in FIGS. 8A and 8B, rails 78, 80 can be moved farther apart after desired 
 cooling by any desired motive means (not shown) so that ledges 86, 88 are 
 wider than the width of flanges 84, to allow molded parts 82 to fall 
 between the rails, as onto a conveyor (not shown). Desirably, the timing 
 for this action is arranged to occur just before the next set of parts are
 ejected from the cores so that the rails can then move back to the closed 
 position to capture the next cycle of ejected parts, although if desired 
 the track means may be relatively movable with respect to the turret block
 and sufficient capacity provided for more than one mold cycle. 
 FIGS. 9-13 show an alternate embodiment wherein the spacing of the spaced 
 track members or rails is kept constant so that the molded parts do not 
 fall between the rails. 
 In this embodiment, turret block 160 is shown in FIG. 9 with two mold core 
 halves 172, each having multiple rows of mold cores 174. Track means 176 
 may be tipped or angled downwards by means of cylinder 192 to allow the 
 molded parts 182 to simply slide off the end of rails 178, 180 onto a 
 conveyor or any desired receiving means after a desired cooling cycle. 
 FIG. 9 shows one mold half including molded parts 182 thereon, while the 
 other mold half is shown without molded parts thereon having previously 
 released same. The track means 176 is shown held in the horizontal 
 position by cylinder 192. The end view of FIG. 10 shows the track means 
 with multiple rows of molded parts held therein for cooling. 
 FIG. 11 shows the molded parts 182 being ejected from one set of mold cores
 174 during rotation of the turret block 160 through its 180 degree arc, 
 while the other set of mold cores has parts 182 molded thereon from mold 
 cavities 194 on mold cavity half 196 held on stationary or fixed platen 
 198. By not having to stop the rotation to eject the parts, valuable cycle
 time can be saved when using a two faced turret block. Also, the rotation 
 of the block can occur during the stroke motion of the block, that is, as 
 the block is opening--moving away from the stationary platen 198 and mold 
 plate or mold cavity half 196, and as the block is closing--moving toward 
 stationary platen 198 and mold cavity half 196. By combining these motions
 cycle time is again optimized. 
 FIGS. 12A & 12B show parts 182 released onto track means 176 and retained 
 between rails 178, 180 on ledge members 186, 188. FIGS. 13A and 13B show 
 track means 176 tipped by cylinder 192 so that parts 182 can simply slide 
 off after desired cooling. 
 Thus, in accordance with the present invention, track means having spaced 
 track members or rails are used to capture parts ejected during rotational
 movement of the turret block for advantageously extended cooling cycles. 
 Cycle time is advantageously minimized enabling the ejection of 
 comparatively thick parts during turret block rotation without risking 
 part damage and providing post mold cooling options. The present invention
 advantageously provides means to optimize cycle time for a turret block, 
 advantageously a two faced turret block, by allowing ejection of partially
 cooled parts during block rotation and simultaneous block stroke motion. 
 In addition, the present invention is simple and convenient to operate on 
 a commercial scale. 
 It is to be understood that the invention is not limited to the 
 illustrations described and shown herein, which are deemed to be merely 
 illustrative of the best modes of carrying out the invention, and which 
 are susceptible of modification of form, size, arrangement of parts and 
 details of operation. The invention rather is intended to encompass all 
 such modifications which are within its spirit and scope as defined by the
 claims.