CA2995539A1 - Stretch blow molding machine having a flying head conveyor loader - Google Patents

Abstract

A loader configured to match the speed of an article carried by the loader to that of the moving upper surface of a conveyor such that the article can be dropped onto the moving upper surface of the conveyor without reduced or eliminated risk of its toppling, wobbling, or falling over.

Description

Stretch Blow Molding Machine having a Flying Head Conveyor Loader Background [1] Stretch Blow Molding Machines are used to reheat thermoplastic preforms and stretch blow mold them into finished articles such as bottles and other containers.

[2] Known examples of such machines include that disclosed in US 5876768, entitled "Machines for the Production of Receptacles of Plastic Material,"
which teaches a reheat stretch blow molding machine having a track for pallets, each carrying two preforms. The pallets pass through an oven arrangement having three parallel paths with heaters arranged between the paths such that three pallets at a time enter and exit the oven.

[3] US 5297950, entitled "Stripping Station," teaches a means for removing blow molded articles from their mandrels, rotating them from an inverted orientation to an upright, or neck up, orientation and releasing them to a "discharge station or outlet".

[4] US 6334766B1, entitled "Takeout Apparatus for Shuttle-Type Plastic Blow Moulding Machines," teaches unloading blown bottles from the mold in an upright, neck up, orientation, trimming them and depositing them in an upright orientation on a take away conveyor.

[5] US 4886443, entitled "Blow Molded Bottle Extraction, Trimming and Discharging Apparatus," teaches unloading blown bottles in an inverted position, reorienting them to an upright position, trimming them and discharging them to a take away conveyor.

[6] US 6386858B1, entitled "Take-out Assembly for Blow Molding Machine,"
teaches "a pick-up unit for grasping a finished workpiece and moving it in a substantially linear direction upwardly away from said wheel to a transfer station. A
second rotary transfer mechanism is mounted at the transfer station for receiving a workpiece from the first pick-up unit and moving the workpiece to an exit station as the first pick-up unit returns to the discharge station to pick up another finished workpiece from the wheel."

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[7] ZQ Machinery has a website "cnziciiang.com/news-D157.html" on which they show a "Video Center" that contains video clips of operating blow molding machinery.
Many examples are shown of various machines blow molding a variety bottles and containers ranging in size and several show how the blown articles are unloaded and discharged onto conveyors. For example -

[8] #9 (page 1) "ZQ-B600-4" shows four bottles being delivered onto a moving conveyor. The bottles are of sufficient diameter to remain stable and not fall over.

[9] #15 (page 1) "ZQ-B1500-4" shows four pop cans being delivered onto a moving conveyor. The cans remain stable and do not fall over.

[10] #2 (page 2) "ZQ-B5000-2" shows two 5 Liter bottles being delivered onto a moving conveyor. The bottles are of sufficient diameter to remain stable and not fall over.

[11] In other video clips there are examples of tall, slender bottles that are discharged directly into air conveyors where they are held by their neck finish support ledge instead of standing on their bases.

[12] In summary, the prior art teaches that blown bottles and containers of sufficient diameter, lack of height or favorable weight distribution can be directly deposited onto a moving conveyor without the risk of them falling over. Blown bottles and containers that are tall, slender or with unfavorable weight distribution that would risk falling over are handled differently. Either they are dropped down a chute into a bin or they are directly discharged into a conveyor which holds only their neck finish support ledge. The prior art lacks a discharge means wherein a tall, slender bottle or container or one having an unfavorable weight distribution is placed in an upright, neck up, orientation directly onto a moving conveyor.
Summary of the Invention

[13] According to one aspect, the present invention provides a handling system wherein a tall, slender bottle or container, and/or possibly having an unfavorable weight distribution, is placed in an upright, neck up, orientation directly onto a moving conveyor while reducing, minimizing, or eliminating the risk of falling over.

Brief Description of the Drawings

[14] The drawings illustrate, by way of example only, embodiments of the present invention.

[15] Fig. 1 is a schematic view of the front of a machine.

[16] Fig. 2 is a schematic view of the discharge area and conveyor of a machine.

[17] Fig. 3 is an end view of the Flying Head Conveyor Loader.

[18] Fig. 4 is a side view of the Flying Head Conveyor Loader in the loading position.

[19] Fig. 5 is a side view of the Flying Head Conveyor Loader in the unloading position.
Detailed Description of the Invention

[20] Figure 1 shows a reheat stretch blow molding machine 10 comprising a preform loading area 12, a preform conditioning area 14, a stretch blow molding clamp 16, an unloading area 18, and an operator interface 11. Each preform is loaded onto a rotatable mandrel mounted on a pallet at the loading area 12. The pallets are moved via a series of tracks through the different areas of the machine in paths, both single and multiple, namely loading, conditioning, blow molding, and unloading to provide a continuous process wherein each preform is conditioned and formed into a final article.

[21] Figure 2 shows the front of the machine 10 and the unloading area 18 that includes a Flying Head Conveyor Loader 200 that unloads the final articles and places them onto a conveyor 210. It is contemplated that, in most installations, the conveyor 210 is continuously running.

[22] Figure 3 shows and end view of the Flying Head Conveyor Loader 200 and the conveyor 210. Also shown is a final molded article, in this case a blown bottle 220, in the unloading area 18 located on a mandrel 22, which is carried by a pallet 24 that is entrained and guided by track 26. The Flying Head Conveyor Loader 200 includes a movable head assembly 230 that includes at least one rotatable gripper assembly 240 that includes a pair of grippers 250 which engage the neck finish/support ledge area 260 of the bottle 220 by means well known to those familiar with the art. Once engaged the grippers 250 remove the bottle 220 (in dashed line) from its mandrel 22 and rotate it approximately 1800 in the direction of arrow "A" to a position where the bottle 220 (in solid line) is held in an upright orientation just above the conveyor 210 as shown in Figure 3.

[23] The movable head assembly 230 is mounted on two horizontal, spaced apart rods 300 and 310 such that it can translate along an axis substantially parallel to the moving direction of the conveyor 210. The movable head assembly 230 is fastened to drive belt 320 by a clamp 330 (see Fig. 4). Drive belt 320 is driven by servomotor 340 such that the movable head assembly 230 can be translated back and forth along the axis.

[24] Figure 4 shows a side view of the Flying Head Conveyor Loader 200. In this example three blown bottles 220 are shown being stripped and handled by a rotatable head assembly 230 that includes three rotatable gripper assemblies 240. In various embodiments, any suitable number of rotatable gripper assemblies 240 can be used.

[25] The three rotatable gripper assemblies 240 are coaxially affixed to shaft that is rotated by servomotor 360 from a mandrel unloading position to a conveyor loading position. Shaft 350 and servomotor 360 are mounted on subframe 370 that translates along rods 300 and 310 and are driven by belt 320 and servomotor 340. The bottles are shown positioned upright and in the conveyor loading position just above the constantly moving conveyor 210 that is travelling in the direction of arrow "B".

[26] Figure 5 shows the movable head assembly 230 translating along rods 300 and 310 at a speed synchronized to match that of the constantly moving conveyor 210 in the direction of arrow "B". Initially the gripper fingers 250 continue to grip the bottle 220 and hold it just above the conveyor's top surface as the movable head assembly 230 accelerates from a standstill until it reaches the same speed as the conveyor 210.
When sensors (not shown) indicate the speeds are synchronized the gripper fingers 250 release the bottle 220 allowing it to drop the short distance onto the top surface of the conveyor 210. The movable head assembly 230 then stops translating in the same direction as the conveyor travel and servomotor 340 reverses direction to return the movable head assembly 230 to its mandrel unloading position for the beginning of the next unloading cycle. Simultaneously as the rotatable gripper assemblies 240 are being returned to their starting positions. The rotatable gripper assemblies 240 are reverse rotated 1800 by servomotor 360 to position grippers 250 in their mandrel unloading position ready to strip the next bottle from its mandrel.

[27] In operation, the matching of the speeds of the upright bottles and the conveyor allows the bottles to be dropped onto the upper surface of the conveyor without the risk of toppling, wobbling or falling over. This is a particularly useful feature when handling tall, slender bottles or other articles having unfavorable shapes or weight distributions that would make them unstable in prior art handling arrangements. The speed matching need not be absolutely exact and some tolerance is contemplated. Moreover, dynamic factors, such as mass and/or inertia of the object being dropped onto the conveyor, can be taken into account when setting the target speed of the movable head assembly.

[28] Other configurations of the invention include mounting the Flying Head Conveyor Loader 220 on a vertically movable frame that is translated along an axis perpendicular to the upper surface of the conveyor, or parallel to the vertical axis of the finished article's mandrel, such vertical translation being effected by a servomotor belt drive similar to that shown in the Figures above. One advantage of this additional axis of movement is to assist the stripping of the finished article from its mandrel by providing an initial vertical lifting motion before the article begins its rotation to its final orientation. A second advantage of this additional movement is to provide vertical adjustment between the movable head assembly in its conveyor loading position and the actual position of the upper surface of the conveyor to accommodate different bottle heights and to minimize the dropping distance at the matched speeds.

[29] Another configuration of the invention includes mounting the Flying Head Conveyor Loader 220 on a horizontally movable frame that is translated along an axis perpendicular to the direction of travel of the entrained mandrels, such horizontal translation being effected by a servomotor belt drive similar to that shown in the Figures above. The advantage of this additional axis of movement is to assist the engagement of the grippers adjacent the neck finish of the article by providing clearance for the arc of swing of the rotatable gripper assembly.

[30] Yet other configurations of the invention also include different numbers of movable head assemblies, grippers, and their associated components to accommodate different numbers of finished articles being produced by the machine in each cycle.

[31] Advantages of the invention include not having to stop or slow the conveyor to load molded articles onto the conveyor in an upright orientation. This can increase total throughput of the system, resulting in more articles being produced in a given time. Moreover, conveyor operation is simplified in that it can be run continuously at the same speed and need not have its speed modulated to accommodate article loading equipment.

[32] While the foregoing provides certain non-limiting examples, it should be understood that combinations, subsets, and variations of the foregoing are contemplated. The monopoly sought is defined by the claims.

Claims (4)

What is claimed is:

1. A loader configured to match the speed of an article carried by the loader to that of the moving upper surface of a conveyor such that the article can be dropped onto the moving upper surface of the conveyor without reduced or eliminated risk of its toppling, wobbling, or falling over.

2. A movable gripper assembly configured to unload a finished blow molded article, rotate the article to an upright orientation, translate the article at a speed that substantially matches the speed of a moving conveyor, and release the article onto the conveyor in an upright orientation.

3. A conveyor loader that matches the speed of an article to be loaded onto the conveyor to the speed of the conveyor.

4. A movable gripper assembly that moves simultaneously along two or more mutually perpendicular axes while loading an article onto a moving conveyor that is moving along an axis parallel to one of the mutually perpendicular axes.