The present invention relates to devices and methods which remove blow-molded products from between open mold halves and transport the products for subsequent processing and, more particularly, to take-out devices for high-speed blow-molding machines.
High-speed blow-molding machines are well known. These machines include a large number of molds arranged in a circle and rotated around the circle at a speed as high as 8-10 revolutions per minute or possibly higher. A continuous parison is or parisons are extruded between open mold halves, which close to capture parison segments in mold cavities. The captured parison segments are blown in the cavities and set to form blow-molded products. The molds open at an ejection station and the products are removed.
Modern blow-molding machines are used with take-out mechanisms which remove the molded products from the molds. One specific product made by blow-molding machines are containers and, even more specifically, bottles. The bottles are conventionally moved by the take-out mechanism to a discard bin if the bottles are defective, placed on a conveyor for transport to a trim station where flash formed during blow molding is removed from the bottles and the bottles are finished as required, or loaded directly into packaging (e.g., boxes) for further transportation.
An older, conventional bottle manufacturing apparatus has, as shown in
An air cylinder 10 is slidably mounted on the body 5 of the apparatus for movement in the up and down direction. A support member 11 is fixed on and extends upwardly from the cylinder 10. The support member 11 has a supporting shaft 12 extending transversely to the support member 11. A tong arm 13 is pivoted on the supporting shaft 12 at one end. This assembly is a take-out mechanism 14 for taking a bottle “A” molded in the blow mold 1 out of the blow mold 1.
The tong arm 13 has a tong head 16 rotatably mounted on a shaft 15 at the end opposite the supporting shaft 12. A chain 18 extends around a sprocket wheel 17a fixedly mounted on the supporting shaft 12 and a sprocket wheel 17b supported by the shaft 15 and on which the tong head 16 is fixedly mounted. A rack 20 engages a gear and is moved up and down by a piston 10a in the air cylinder 10. Tongs 21 are mounted on the tong head 16 and adapted to grip a mouth portion of the bottle “A” molded in the blow mold 1 and then to release the bottle A.
A threaded shaft 22 engages the air cylinder 10 and rotates on the body 5 of the apparatus. An operating shaft 24 drives the threaded shaft 22 through a rotary driving mechanism 25. A conveyor 26 transfers a molded bottle A away from beneath the take-out mechanism 14.
Some blow-molding machines use multi-cavity molds able to mold sets of bottles during each cycle of operation. It is conventional to remove a bottle from a single-cavity blow mold using a vacuum plug inserted into the neck of the bottle. Such take-out mechanisms cannot rapidly and reliably remove sets of blow molded bottles from plural-cavity molds, however, and place the bottles in a take-away conveyor while maintaining the orientation of the bottles in the sets. U.S. Pat. No. 6,062,845 issued to Conaway et al. addresses this problem.
Conaway et al. disclose a take-out mechanism for removing sets of blow-molded bottles from a blow mold. The mechanism includes a rotary turret, a take-away conveyor, and a drive for moving the turret between the blow mold and the take-away conveyor. The turret has a number of sides with a plurality of vacuum plugs extending from each side. The drive moves the turret toward the mold to extend a set of plugs on one side of the turret into mold cavities and vacuum-capture bottles molded in the cavities. After opening of the mold, the turret is lowered and rotated 90 degrees to position the vacuum-held bottles at the infeed end of the take-away conveyor. Rotation of the turret positions a second set of plugs facing a second mold moved to the take-out position. Subsequent rapid retraction of the turret moves the set of removed bottles into the take-away conveyor and powers the conveyor to receive the bottles while maintaining orientation between individual bottles. The turret is raised to remove the plugs from the bottles held in the conveyor and then rapidly extended back to the next mold to position the second set of plugs in bottles in the mold.
Some take-out mechanisms are directed to particular types of blow-molding machines. For example, U.S. Pat. No. 6,923,933 issued to Fiorani et al. teaches a take-out device for removing blow-molded products from molds in a high-speed rotary blow-molding machine. The device includes a plurality of transfer heads which are moved in to and out of an ejection station to clamp bottles stripped from the molds and move the bottles away from the station toward a take-away conveyor. The bottles are turned ninety degrees before placement on the take-away conveyor.
Other take-out mechanisms are designed to facilitate specific operations. For example, U.S. Pat. No. 7,632,089 issued to Bates et al. teaches a take-out and cooling operation. The apparatus conveys molded plastic articles from a molding machine to and through a cooling station. The take-out mechanism has a main support, a conveyor carried by the main support for movement in an endless path, a cam adjacent to the support, a plurality of arms carried by the conveyor for movement with the conveyor along the endless path and including a follower responsive to the contour of the cam to vary the position of the arms relative to the support, and at least one holder carried by each arm. Each holder is adapted to receive and carry at least one molded article to facilitate in conveying the molded articles and is flexible and resilient to permit relative movement of at least a portion of the holder relative to its associated arm.
There remains a need in the art for an improved apparatus and method that overcome the shortcomings of conventional solutions. An object of the present invention is to decrease the cycle time (i.e., increase the speed of production output) required to manufacture plastic products (specifically containers and more specifically bottles). A related object is to reliably and rapidly transfer blow-molded products from open molds of blow-molding machines at an ejection station to a take-away position such as on a conveyor. A further related object is to complete such transfer without disturbing the relative positions of the bottles during removal and placement on the conveyor. Still another related object is to provide a take-out mechanism that operates at a high production rate and is capable of removing a set of bottles from a mold faster than every two seconds.
Another object is to provide a universal take-out mechanism versatile enough to work with different types of blow-molding machines and facilitate different operations. A related object is to permit the operator to program changes for different bottles and applications without implementing any mechanical changes.
Yet another object is to decrease the cost and complexity of the take-out mechanism. A related object is to avoid complicated tooling required to engage a particular size and shape bottle. Further related objects are to reduce the number of components and to provide a lighter weight assembly all with a smaller footprint. It is still another object of the present invention to provide a take-out mechanism that physically captures the blow-molded products between mold halves at an ejection station without abruptly changing the velocity of the products, moves the captured products away from the mold without gravity release, and places the captured products on a take-away conveyor in a known position for subsequent processing. The take-out device should operate without damage to the blow molded products.
To achieve these and other objects, and to meet these and other needs, and in view of its purposes, the present invention provides a takeout for transferring products from the mold of a blow-molding machine to a discharge position. The takeout has two, connected, mirror-image frame members defining parallel planes. A flexible slide is connected to each respective frame member on one end and to a respective arm on the opposite end. The arms have lifting fingers which hold, carry, and release a product. Carriages provide tracks along which the arms travel in the horizontal direction; the carriages themselves travel along guides of the frame members in the vertical direction. Driven by motors, belts carry each arm and its lifting finger along predetermined, closed, endless paths including a mold position, a series of intermediate positions, and a discharge position. A computer controls independently one or more of the on-off status, the direction of rotation, and the speed of rotation of each of the motors and controls independently each of the lifting fingers.
More specifically, the takeout has a first frame member with a generally rectangular shape and a pair of first guides. The first frame member defines a first plane with a horizontal direction and a vertical direction. A second frame member is connected to the first frame member, has a generally rectangular shape and a pair of second guides, and defines a second plane parallel to the first plane.
A first flexible slide has a foot connected to the first frame member and a head connected to a first arm. The first flexible slide moves in the first plane defined by the first frame member to locate the first arm at any point in the first plane. A second flexible slide has a foot connected to the second frame member and a head connected to a second arm. The second flexible slide moves in the second plane defined by the second frame member to locate the second arm at any point in the second plane.
A pair of first motors is affixed to the first frame member. Each of the pair of first motors rotates independently in the same direction or in opposite directions. A pair of second motors is affixed to the second frame member. Each of the pair of second motors rotates independently in the same direction or in opposite directions.
A first belt associated with the first frame member is driven by the independent operation of each of the pair of first motors and carries the first arm. A second belt associated with the second frame member is driven by the independent operation of each of the pair of second motors and carries the second arm.
A first carriage having a first track along which the first arm travels in the horizontal direction, itself travels along the pair of first guides of the first frame member in the vertical direction. A second carriage having a second track along which the second arm travels in the horizontal direction, itself travels along the pair of second guides of the second frame member in the vertical direction. First and second lifting fingers are carried by the first and second arms, respectively, each of the lifting fingers holding, carrying, and releasing a product. A computer controls independently one or more of the on-off status, the direction of rotation, and the speed of rotation of each of the motors and controls independently each of the lifting fingers.
The first arm and the first lifting finger move along a first, predetermined, closed, endless path including a mold position, a series of intermediate positions, and a discharge position. The second arm and the second lifting finger move along a second, predetermined, closed, endless path including a mold position, a series of intermediate positions, and a discharge position. The first path and the second path may be identical and, if so, travel of the first arm along the first path is out of phase with travel of the second arm along the second path to avoid collisions.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention.
The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:
The assignee of the present application has been operating, in its plants for some time, a sophisticated bottle take-out system 100 in combination with its high-speed blow-molding machines. The bottle take-out system 100 is illustrated in
A single servo motor 108 drives a chain 110. Chain idler sprockets 112 are mounted to the frame 102. At least one chain tensioner 114 is also provided. The chain 110 is driven by the servo motor 108 with the idler sprockets 112 as well as the chain tensioners 114 to achieve a smooth indexing motion.
A main lifting cylinder 126 lifts the fingers 122 and bottles A, B up and away from the mold 1, allowing the bottles A, B to be carried by the fingers 122 along the track 106. A stabilizer plate 128 is provided to guide the bottles A, B. An air manifold 130 provides air to the cylinders 124, 126 to activate them. A separate rotary union supplies air to a two-port receiver. The two-port receiver is connected to channel air to the other side of the pick-up assembly 120 via channels through the air manifold 130.
Cam contact plates 132 are provided. Each cam contact plate 132 has four idler rollers 134. A three-point contact of the rollers 134 is assured with the track 104. There is always a single roller engaged. A pair of trackers 136 are also provided. Each tracker 136 has a roller bearing 138 and an elastomeric (e.g., rubber) projection 140. The roller bearings 138 run inside the track 106 and the projections 140 apply tension at all times and contact with the track 106.
The sequence of operation begins with the pick-up assembly 120. The mold 1 stops and the bottle-lifting station is waiting. The main lifting cylinder 126 is actuated and lowers the lifting fingers 122 into the necks of the bottles A, B. The lifting finger cylinders 124 are activated, swelling rings on the lifting fingers 122 which grip the necks of the bottles A, B. The mold 1 then opens and the chain 110 indexes, lifting both bottles A and B upward, and the main lifting cylinder 126 moves to its “up” position. The next index performs the same action with the next station.
The bottles A, B are carried along the track 106 by the chain 110 until they reach the unload or drop station. Once the bottles A, B reach the unload station, the lifting finger cylinders 124 are activated, relaxing the rings on the lifting fingers 122. The main lifting cylinder 126 is actuated and moves up, pulling the lifting fingers 122 out of the necks of the bottles A, B. The chain 110 then indexes to the next position. A stripper plate is actuated blocking the bottles A, B from following the lifting fingers 122 once the bottles A, B are released.
The bottle take-out system 100 has eight take-out stations positioned in a large, rectangular loop traveled by the chain 110. Four stations are disposed along the top and four are disposed along the bottom of each track 106. Each station removes two bottles A, B from the blow-molding machine at once. The system 100 is about two meters long and takes about 3.8 seconds to remove a bottle A and deposit the bottle A on a conveyor 26.
In view of the need for an even faster and more versatile takeout, which requires less floor space, the present invention further improves the take-out system 100. The improved takeout 200 has two take-out stations, is only 1 to 1.5 meters long, and is faster than the take-out system 100. Various embodiments of the improved takeout 200 and method of the present invention are described in detail below.
As shown in
The foot 212 of a first flexible slide 214 is fixed (e.g., fastened) to the base 204b of the first frame member 204. The first flexible slide 214 is attached on its head 216 to a first arm 220. The first flexible slide 214 includes a belt 211, preferably made of plastic. The belt 211 performs a function like the chain 110 of the take-out system 100, and the chain 110 could be used in the takeout 200, but the belt 211 offers the advantages of smoother travel and less weight. If desired, the first flexible slide 214 can house electrical components, pneumatic components, or both types of components. The first flexible slide 214 moves in the x-y plane (see the coordinates shown in
With the first flexible slide 214 attached, the first arm 220 travels along a first track 222 of a first carriage 224 in the horizontal, back-and-forth, x-direction. The first carriage 224 travels in the vertical, up-and-down, y-direction along a pair of first guides 226a and 226c placed in the front upright 204a and rear upright 204c, respectively. The first carriage 224 carries four passive pulleys 234 that facilitate travel by the first arm 220 along the first track 222 in the first carriage 224.
A pair of servo motors 228a and 228c are fixed to the first frame member 204 and located proximate the junctions between the front upright 204a and top 204d and between the rear upright 204c and top 204d, respectively. Each motor 228a, 228c independently drives the belt 211 through a respective drive sprocket 230a and 230c (see
As previously noted, the second frame member 206 is a mirror image of the first frame member 204 along the centerline 205. The second frame member 206 has a front upright 206a, a base 206b, a rear upright 206c, and a top 206d. The second frame member 206 may be formed from four, separate components connected together, for example, by brackets and fasteners. Alternatively, the second frame member 206 may be an integral component.
The foot 242 of a second flexible slide 244 is fixed (e.g., fastened) to the base 206b of the second frame member 206. The second flexible slide 244 is attached on its head 246 to a second arm 250. The second flexible slide 244 includes a belt 211. If desired, the second flexible slide 244 can house electrical components, pneumatic components, or both types of components. The second flexible slide 244 moves in the x-y plane (see the coordinates shown in
With the second flexible slide 244 attached, the second arm 250 travels along a second track 252 of a second carriage 254 in the horizontal, back-and-forth, x-direction. The second carriage 254 travels in the vertical, up-and-down, y-direction along a pair of second guides 256a and 256c placed in the front upright 206a and rear upright 206c, respectively. The second carriage 254 carries four passive pulleys 264 that facilitate travel by the second arm 250 along the second track 252 in the second carriage 254.
A pair of servo motors 258a and 258c are fixed to the second frame member 206 and located proximate the junctions between the front upright 206a and top 206d and between the rear upright 206c and top 206d, respectively. Each motor 258a, 258c independently drives the belt 211 through a respective drive sprocket 260a and 260c. A pair of passive pulleys 262a and 262c are fixed to the second frame member 206 and located proximate the junctions between the front upright 206a and base 206d and between the rear upright 206c and base 206d, respectively (see
The motors 228a, 228c fixed to the first frame member 204 and the motors 258a, 258c fixed to the second frame member 206 are each controlled by computer program code in a central processing unit (CPU) of a computer 240. The computer 240 sends signals 238 to each of the motors 228a, 228c, 258a, and 258c. The signals 238 can be sent either along physical connections or wirelessly, as would be understood by an artisan. The operator interacts with the computer 240 and, via the computer 240, directs the operation (e.g., on or off, direction of rotation, speed of rotation) of each of the motors 228a, 228c, 258a, and 258c independently. The programmable nature of the motors 228a, 228c, 258a, and 258c allows flexibility to accommodate various applications and bottle configurations.
Thus, the present invention can further be embodied in the form of computer-implemented processes and apparatus for practicing such processes, for example, and can be embodied in the form of computer program code embodied in tangible media, such as floppy diskettes, fixed (hard) drives, CD ROM's, magnetic tape, fixed/integrated circuit devices, or any other computer-readable storage medium, such that when the computer program code is loaded into and executed by the computer 240, the computer 240 becomes an apparatus for practicing the invention. The program may be embodied in a carrier where a carrier may be a diskette, CD-ROM or transmitted carrier wave.
Focusing on the motors 228a, 228c fixed to the first frame member 204, with the understanding that the motors 258a, 258c fixed to the second frame member 206 operate in a similar manner, the motors 228a, 228c may be directed to rotate in the same (e.g. clockwise) or in opposite directions. Therefore, the independent operation of the motors 228a, 228c permits four possibilities. (1) If the motors 228a, 228c rotate together in one direction, then the first carriage 224 is pulled vertically upward along the first guides 226a, 226c. (2) If the motors 228a, 228c rotate together in the opposite direction, then the first carriage 224 is pulled vertically downward along the first guides 226a, 226c. (3) If one motor 228a rotates in one direction (e.g., clockwise) while the other motor 228c rotates in the opposite direction (counter-clockwise), then the first arm 220 moves horizontally toward the front upright 204a along the first track 222 in the first carriage 224. (4) If the motor 228a rotates in different direction (e.g., counter-clockwise) while the other motor 228c rotates in the opposite direction (clockwise), then the first arm 220 moves horizontally toward the rear upright 204c along the first track 222 in the first carriage 224. The coordinated, independent operation of the motors 228a, 228c allows the operator to position the first arm 220 at any desired point in the entire x-y plane.
The travel of the first arm 220 begins in the initial position P1 of
The travel of the first arm 220 ends in the terminal position P3 of
After discharging the bottles A at the terminal position P3, the first arm 220 then returns (empty, i.e., without carrying any bottles A) to the initial position P1. Of course, the second arm 250 traverses its own predetermined travel path simultaneously as the first arm 220 completes its travel path. The travel path for the first arm 220 may be the same as or entirely different from the travel path for the second arm 250, and the first arm 220 may traverse its travel path faster or slower than the second arm 250 traverses its travel path. Typically, although not necessarily, the first arm 220 is located at the initial position P1 while the second arm 250 is located at the terminal position P3. All that is required, however, is that the two arms 220, 250 be out of phase so that collisions are avoided (i.e., the second arm 250 is never located at the same position occupied by the first arm 220).
The three lifting fingers 272 carried by the leg 270 attached to the first arm 220 may be (but are not necessarily) aligned in the same vertical planes (all three planes are parallel with the first frame member 204 and with the second frame member 206) with the three lifting fingers 272 carried by the leg 270 attached to the second arm 250—as illustrated in
Each of the lifting fingers 272 has a lifting finger cylinder 276. The lifting finger 272 enters the neck of the bottle A to lift the bottle A up. The lifting finger cylinder 276 moves the lifting finger 272 up and down and in to and out of engagement with the bottle A. Thus, when the lifting finger 272 is to engage the bottle A at the initial position P1, the first arm 220 or the second arm 250 (as the case may be) lowers the lifting finger 272 into the neck of the bottle A. The lifting finger cylinder 276 is activated to expand a flexible, elastomeric ring 280 (e.g., a rubber Leopold ring) against the inside surface of the bottle A. The ring 280 applies sufficient pressure to clamp or hold and to carry the bottle A without applying an undesirable amount of pressure as might risk damage to the bottle A. As the ring 280 expands, it can correct for minor offset or misalignment between the bottle A and the lifting finger 272.
Thus clamped by the lifting finger 272, the bottle A is carried by the first arm 220 or the second arm 250 along the predetermined path of the first arm 220 or the second arm 250 (as the case may be) until the bottle A reaches the terminal position P3. At the terminal position P3, the lifting finger cylinder 276 is again activated, relaxing the ring 280 on the lifting finger 272. The first arm 220 or the second arm 250 (as the case may be) raises the lifting finger 272 out of the neck of the bottle A and discharges the bottle A. The computer 240 controls the operation of the lifting finger cylinder 276.
The lifting finger 272 may have an internal channel 278, used to evacuate hot air from inside the bottle A, and an inner pin 288. The lifting finger cylinder 276 is affixed to a flange 282 of the lifting finger 272 using suitable fasteners, as would be known to an artisan, such as screws 284. The lifting finger 272 is attached to the associated leg 270 by suitable fasteners, such as a nut and washer combination 286. An adjustment housing 290 is provided proximate each lifting finger 272 to permit adjustment and facilitate operation of the lifting finger 272. The adjustment housing 290 is attached to the associated leg 270 by suitable fasteners, such as a screw and washer combination 298.
The flexible rings 280 are retained on the lifting fingers 272 by the combination of an upper holder 292 and a lower holder 294. A nut 296 is disposed under the lower holder 294 to complete the assembly. The flexible rings 280 may prevent damage to the lifting fingers 272 should the lifting fingers 272 encounter interference. The lifting fingers 272 may be constructed and arranged to break away at a force low enough to prevent damage to the associated leg 270 and arm 220, 250 in such a situation.
The apparatus and method of the present invention offer a number of advantages. Among those advantages is speed. The takeout 200 extracts bottles A from an indexing blow-molding machine running at a high rate of speed. The takeout 200 completes the tasks of engaging and clamping the bottle A, and extracting and clearing the bottle A from the mold 1, before the mold 1 indexes from the take-out station to its next station. Although the upper limit of the speed capability of the takeout 200 is unknown, tests have shown that speed is not a limiting factor to operation of the takeout 200. Certainly, the takeout 200 improves upon the speed achieved with conventional take-out mechanisms. The takeout 200 is capable, for example, of removing a set of bottles A from a mold 1 faster than every two seconds. Another advantage is flexibility. The operator can program changes for different bottles and applications without implementing any mechanical changes. Still another advantage is cost reduction relative to conventional take-out systems, the result of a reduced number of components and lighter weight assembly all with a smaller footprint.
In operation, the takeout 200 can be used as follows. The method of use begins by providing the takeout 200. Next, the various components (e.g., the motors 228a, 228c, 258a, and 258c and lifting finger cylinders 276) of the takeout 200 are programmed using the computer 240. The first arm 220 with its attached leg 270 and lifting fingers 272 is moved to the initial position Pl. The lifting finger cylinder 276 for the lifting fingers 272 of the first arm 220 is activated to prompt the lifting fingers 272 to pick up bottles A. The first arm 220 then carries the bottles A through the intermediate positions P2 and to the terminal position P3. Simultaneously, the second arm 250 moves toward the initial position P1. The lifting finger cylinder 276 for the lifting fingers 272 of the first arm 220 is activated to prompt the lifting fingers 272 to discharge the bottles A from the first arm 220 at the terminal position P3. The lifting finger cylinder 276 for the lifting fingers 272 of the second arm 250 is activated to prompt the lifting fingers 272 to pick up bottles A at the initial position P1 (either just before, simultaneous with, or just after the first arm 220 discharges bottles A at the terminal position P3). The first arm 220 then moves toward the initial position P1 to pick up the next set of bottles A, while the second arm 250 begins its predetermined path carrying bottles A through the intermediate positions P2 to the terminal position P3, where the lifting finger cylinder 276 for the lifting fingers 272 of the second arm 250 is activated to prompt the lifting fingers 272 to discharge the bottles A from the second arm 220. The first and second arms 220, 250 repeatedly traverse their respective, predetermined, closed, endless paths as often as desired for the particular application.
Although illustrated and described above with reference to certain specific embodiments and examples, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention. It is expressly intended, for example, that all ranges broadly recited in this document include within their scope all narrower ranges which fall within the broader ranges. Two arms 220, 250 are described above and illustrated in the figures; the present invention is not limited to that number.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/PL10/50010 | 3/13/2010 | WO | 00 | 12/1/2010 |