JP3705244B2 - Gripper device for hollow body gripping - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gripper device for gripping and transferring a preform, a bottle or the like in a blow molding line for blow molding a hollow body such as a PET bottle.
[0002]
[Prior art]
The process of manufacturing containers such as PET bottles by blow molding involves forming a preform by injection or extrusion molding, heating the preform to a temperature that can be deformed during blow molding, and then transferring it to the blow molding station. It consists of a process of blow molding. The preform is already molded in the same shape as the mouth and neck of the bottle that finally obtains the mouth and neck. Generally, in the case of a PET bottle, a screw thread for screwing a cap is formed on the mouth and neck and a predetermined amount is provided below the thread. A flange is formed at an interval. And in the case of a bottle for additive filling (aseptic filling), a ratchet for locking the cap is generally formed above the flange.
[0003]
On the other hand, in the conventional gripper device, as shown in FIG. 8, the gripping portion 61 is formed of an arc-shaped flat gripping surface 62 formed in the vicinity of the tip of the fork 60, and grips the neck of the preform. ing. However, gripping the preform generally grips a relatively small gap portion of the cylindrical portion between the screw thread end and the upper end of the flange or ratchet, so that the thickness of the grip portion of the fork cannot be increased, and at most 4 mm Degree. In addition, since the preform surface is rather rough and wavy, when gripping with a conventional gripper device, the preform surface is essentially gripped with a single line contact or a point contact with each fork. There is a drawback that the gripping force is weak and the posture of the object to be gripped is not stable, and it is tilted and gripped or tilted during transfer. In particular, when the end of the screw thread is exposed at the neck portion of the bottle mouth for aseptic filling or when a preform having a ratchet is gripped, the tendency is further increased. In the blow molding line, especially the delivery of the preform from the gripper of the inverting wheel to the spindle of the heating wheel requires a high degree of positioning accuracy, and if the positioning accuracy is poor, the preform cannot be accurately attached to the spindle, Not only does it cause poor heating due to defective heating but also poor yields, and the problem of not being able to speed up the line is that the preform gets caught in the machine due to poor mounting, causing the machine to stop or break parts. is there. Therefore, in the blow molding line, it is indispensable to stably transfer the preform in an accurate posture with the gripper device, but the conventional gripper device is insufficient to satisfy the demand.
[0004]
[Problems to be solved by the invention]
Therefore, the present invention intends to solve the above-mentioned drawbacks of the conventional gripper device at once, and accurately positions a hollow body such as a preform or a bottle even if it is a preform with a ratchet and firmly Provided is a gripper device having a gripper that can be gripped and can maintain a stable posture without being inclined during conveyance and can transfer and deliver a hollow body such as a preform with accurate positioning accuracy. It is intended to do.
[0005]
[Means for Solving the Problems]
The gripper device for gripping a hollow body according to the present invention that achieves the above object is a gripper device for gripping a hollow body formed by pivotally mounting a pair of forks having gripping portions so that the gripping portion can be opened and closed. The groove-shaped depression is formed along the circumferential direction on the gripping surface.
[0006]
By forming a flange curved concentrically with the gripping surface of the gripping part on the side surface in the vicinity of the gripping part of the fork, even a preform having a ratchet can be held more stably in an accurate posture. it can. And the gripper can be reversed and used by forming the flange symmetrically on both sides of the side surface near the gripping portion. Further, in the present invention, when the gripper is not used in an inverted manner, it is not necessary to make the flange symmetrical in the vertical direction, but by projecting and forming a flange that is concentrically curved with the grip surface of the grip portion aligned with the preform neck and neck. Compared with the conventional gripper device, the preform can be stably held, and the second object can be achieved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a gripper device according to an embodiment of the present invention will be described in detail with reference to FIGS.
The gripper device of this embodiment shown in FIGS. 1 and 2 is a gripper device particularly suitable for gripping a preform for an aseptic filling bottle. As shown in FIG. 5, the aseptic preform 30 generally has a ratchet 32 formed at an upper position of the flange 31 of the mouth-and-neck portion. To grip. The gripper device of this embodiment has a pair of forks (only one of the forks is shown in FIG. 1) 1 that is pivotally attached to a fixed frame so as to be openable and closable. Is the same as the conventional one in that the grip portion 2 having an arc-shaped grip surface is formed, but the circumferential groove-shaped recess 3 is formed on the grip surface 4 of the grip portion 2. And a flange 5 having a circular arc shape concentric with the gripping surface is formed on the outer peripheral portion of the gripping portion.
[0008]
The groove-shaped recess 3 is for releasing deformation such as undulation of the surface of the object to be gripped, and is formed along the center of the gripping surface 4 in the width direction. It is sufficient that the depth is such that only both side portions of the recess come into contact without direct contact, and a depth of 0.3 to 1 mm, preferably 0.4 to 0.7 mm is desirable. The flange 5 is provided to lightly support the ratchet portion of the preform and prevent the preform from shaking or tilting so that the preform axis can be accurately gripped with the grip center line. The outer diameter of the ratchet is the same as that of the outer diameter of the ratchet or is formed to face each other with a slight gap. In the gripper device, the fork is inverted during the work of transferring the preform and used alternately up and down (left and right in FIG. 1). Therefore, the flanges 5 are provided symmetrically on both sides of the fork 1 as shown in FIG. It has a collar-shaped flange.
[0009]
Regarding the dimensional relationship between the flange 5 and the preform to be gripped, the clearance a between the arc inner peripheral surface of the flange and the ratchet outer peripheral surface is 0 to 1.5 mm, preferably 0.05 to 0.2 mm (see FIG. 5). ). The gap b between the flange lower end and the preform flange upper surface is in the range of 0 to 3 mm, preferably 0.5 to 1.5 mm. If they are formed to have the same dimensions so that there is no gap at all, dimensional errors such as waviness on the outer surface of the preform cannot be absorbed, and if there are too many gaps, vibration and tilt will be allowed. The above-described dimensional relationship is more preferable in order to make the hearts coincide and accurately hold in a stable posture.
[0010]
The gripper device of the present embodiment is formed as described above, and the groove-like depression 3 is provided on the gripping surface 4, so that the gripping portion of the fork contacts at least two lines or two points parallel to the outer peripheral surface of the preform. Thus, the axis of the preform can be accurately aligned and firmly held. Moreover, since the flange 5 is provided, as shown in FIG. 5, for example, when the preform 30 with a ratchet such as an aseptic preform is gripped, the flange 5 contacts the outer surface of the ratchet unless the grip is accurate. Positioning is possible, and more stable preform holding can be obtained. Further, it is possible to prevent the gripped preform from being inclined during conveyance, and to transfer the preform in a stable posture. Accordingly, the preform can be accurately delivered to the spindle of the heating wheel that requires particularly high positioning accuracy, and the preform can be uniformly heated in the circumferential direction.
[0011]
3 and 4 show a fork of a gripper device according to a second embodiment of the present invention. As shown in FIG. 6, the gripper device is applied to gripping a preform 40 for a bottle that does not have a ratchet at the neck of a bottle mouth such as a heat-resistant bottle. The difference from the gripper device of the above embodiment is that the upper part of the flange 41 of the preform 40 is gripped according to the shape of the preform (bottle), and the end of the flange 5 of the fork is the upper surface of the flange 41 of the preform. The shape of the flange 11 of the fork 10 is merely changed short so that it can be confronted with a slight gap between the two and the technical idea is the same. Reference numerals are assigned and detailed description is omitted.
[0012]
As mentioned above, although embodiment concerning the gripper device concerning the present invention was described, the present invention is not restricted to the above-mentioned embodiment, and various design changes are possible within the range of the technical idea. The gripper device is desirably provided with a flange on the fork as in the embodiment shown in FIGS. 1 to 6. For example, a preform without a ratchet, such as a heat-resistant or carbonated beverage preform other than aseptic, or In the case of a cylindrical article or the like that does not have a flange, the fork may not be provided with a flange. The fork 50 of the gripper device of the third embodiment shown in FIG. 7 is the same as that of the above embodiment in that a groove-like recess 53 is provided on the arc-shaped gripping surface 54 of the gripping portion 52. Is not provided. On the contrary, even if only the flange is provided without providing the groove-like depression on the gripping surface, the preform can be gripped more stably than the conventional gripper device. Further, in the above-described embodiment, the flange formed on the fork prevents the object to be grasped from inclining by contacting the ratchet of the object to be grasped. When the threads are at the same height, the preform may be gripped such that a part of the flange is in contact with a part of the thread.
[0013]
【The invention's effect】
The present invention is configured as described above and has the following special effects.
According to the grip device of the present invention, since the groove-shaped depression is provided on the gripping surface of the gripper gripping portion, at least two gripped objects are provided by each fork even if the gripping surface of the gripping object is rough. Thus, the gripping becomes firm, the posture of the object to be gripped is stabilized, and the preform and the like can be delivered and conveyed with accurate positioning accuracy.
[0014]
In addition, by forming a flange that is curved concentrically with the gripping surface of the gripping part on the side surface in the vicinity of the gripping part of the fork, even when gripping a preform with a ratchet such as an aseptic preform, it is more stable. Grip is obtained and tilting is prevented during conveyance. Further, by forming the flanges symmetrically on both sides of the side surface in the vicinity of the gripping portion, the grippers can be reversed and used alternately.
[Brief description of the drawings]
FIG. 1 shows a fork of a gripper device according to a first embodiment of the present invention, wherein (a) is a left side view and (b) is a front view.
2A is a cross-sectional view taken along the line AA in FIG. 1B, and FIG. 2B is a view taken along the line BB.
3A and 3B show a fork of a gripper device according to a second embodiment of the present invention, in which FIG. 3A is a left side view, and FIG. 3B is a front view.
4A is a cross-sectional view taken along the line CC in FIG. 3B, and FIG. 4B is a view taken along the line DD.
FIG. 5 is a longitudinal sectional view showing a state in which the gripper device according to the first embodiment is holding an aseptic preform.
FIG. 6 is a longitudinal sectional view showing a state where the gripper device of the second embodiment is holding a heat-resistant bottle preform.
7A and 7B show a fork of a gripper device according to a third embodiment of the present invention, in which FIG. 7A is a left side view, FIG. 7B is a front view, and FIG.
8A and 8B show a fork of a conventional gripper device, where FIG. 8A is a left side view and FIG. 8B is a front view.
[Explanation of symbols]
1, 10, 15, 50 Fork 2, 52 Grip part 3, 53 Groove-like depression 4, 54 Grip surface 5, 11 Flange 30, 40 Preform

Claims (4)

In a gripper device for gripping a hollow body in which a pair of forks having a gripping portion are pivotally mounted so as to be openable and closable, the gripping portion is formed by an arc-shaped gripping surface, and the gripping surface has a groove shape along a circumferential direction. A gripper device for gripping a hollow body, wherein a recess is formed. The gripper device according to claim 1, wherein a flange that is concentrically curved with a gripping surface of the gripping part is formed on the side surface in the vicinity of the gripping part of the fork. The gripper device according to claim 2, wherein the flange is formed on both sides or one side of the side surface in the vicinity of the grip portion. In a gripper device for gripping a hollow body formed by pivotally mounting a pair of forks having a grip portion so as to be openable and closable, the grip portion is formed of an arc-shaped grip surface, and the grip portion A gripper device for gripping a hollow body, characterized in that a flange that is concentrically curved with the gripping surface of the hollow body is projected.

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