Transport apparatus

A transport apparatus (300) for transporting a preform (200) for blow molding comprises: a transport device that transports the preform while allowing the preform to rotate on its axis in a horizontal direction; and an engaging device (310) that engages the preform being transported while being allowed to rotate on its axis, and setting the orientation of the preform to a predetermined orientation. The engaging device engages a convexity or a concavity provided in the outer periphery of the preform.

TECHNICAL FIELD

This invention relates to a transport apparatus.

BACKGROUND ART

As a blow molding apparatus in which a preform is disposed in a blow cavity mold and blow-molded into a container, there has been known an injection stretch blow molding apparatus operated by a so-called 1.5 stage process (see, for example, Patent Document 1). The injection stretch blow molding apparatus by the 1.5 stage process adopts a 1 stage process connecting an injection molding section and a blow molding section inline, but has the advantage of a 2 stage process in which the number of products simultaneously injection molded and the number of products simultaneously blow molded are inconsistent.

Such a blow molding apparatus is provided with a transport line for transporting the preforms continuously. The transport line, for example in Patent Document 1, has a plurality of sprockets, a plurality of transport members capable of engaging the plurality of sprockets for holding the preforms, and a guide rail for guiding the transport members along a transport direction.

If the shape of the container is a uniform shape in a diametrical direction, such as a nearly circular shape in a plan view, the preform is also of a uniform shape nearly circular in a plan view. Depending on the shape of the container, however, there may be a case where the shape of the preform is not uniform in the diametrical direction of the preform, for example, a case in which the preform is elliptical in a plan view, or a case in which the thickness of the preform is not uniform. Such a preform is used, for example, in molding a flat container or a square-shaped container.

When the flat container is to be molded by the so-called 2 stage process, it is necessary to impart a heat distribution to the preform in its major-axis direction, and a heating technique, for example, as in Patent Document 2, is used.

PRIOR ART DOCUMENTS

Patent Documents

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

With the technique concerned with Patent Document 2, however, control is complicated, or the device involved is itself expensive. Since the preform is heated from a room temperature state, moreover, the use of the preform, if partly thick-walled in the diametrical direction, is a disadvantage from the aspect of energy.

On the other hand, a blow molding apparatus employing the 1 to 1.5 stage process, as in Patent Document 1, can utilize so-called potential heat, heat remaining in the preform after injection molding. The value of this potential heat is greater in the part having a thicker wall. That is, simply by thickening side parts of the preform corresponding to the parts across the major diameter of the container, without adopting a special heating technique, a flat container with a uniform wall thickness distribution can be molded. Furthermore, the effective use of the potential heat inherent in the preform is believed to bring advantage to the 1 to 1.5 stage process over the 2 stage process in terms of energy.

In this case, the blow molding apparatus according to the 1.5 stage process requires that in conformity with the major diameter and minor diameter of the blow cavity molds, the preforms need to be brought into an aligned state in which the preforms are aligned with the orientations of the major and minor diameters.

With the device of Patent Document 1, however, the preforms held by the transport members are not tightly fitted to the transport members. Because of vibrations associated with transport, therefore, the preforms rotate with respect to the transport members, and the orientations of the preforms being transported may deviate. If the preforms are in an elliptical shape, for example, the major axis direction of the preforms being transported may deviate.

In such a situation, a misaligned state occurs in which the orientations of the respective preforms being transported are nonuniform. If a blow molding step is performed in this state, the problem arises that desired blow molding cannot take place.

Such a problem is common to a case where the preforms are of a uniform shape in the diametrical direction of the preforms, and a case where blow molding is to be performed, with the preforms being oriented in the same direction.

The present invention has been accomplished to solve the foregoing problems of the conventional technologies. It is an object of the invention to provide a transport apparatus which can align the orientations of the preforms with the same orientation during continuous transport.

Means for Solving the Problems

The transport apparatus of the present invention is a transport apparatus for transporting a preform for blow molding, comprising: a transport device that transports the preform while allowing the preform to rotate on an axis thereof in a horizontal direction; and an engaging device that engages the preform being transported while being allowed to rotate on the axis thereof, and setting the orientation of the preform to a predetermined orientation, wherein the engaging device engages a convexity or a concavity provided in the outer periphery of the preform.

In the present invention, the transport apparatus is equipped with the engaging device which engages the preform being transported while being allowed to rotate on the axis thereof, and sets the orientation of the preform to the predetermined orientation. As a result, each preform can be oriented in the same direction during continuous transport.

Preferably, the engaging device has a rolling member, the rolling member is configured to be capable of moving in a groove part formed in the transport apparatus, and the groove part has, at a predetermined position, a retreat area formed so that the relative distance between the engaging device and the preform lengthens. Since the retreat area is formed, the engaging device can be configured to become separable from the preform easily. Consequently, the preforms can be oriented more accurately in the same direction during continuous transportation.

In preferred embodiments of the present invention, the engaging device has a support portion, one end of the support portion is provided with a protrusion formed to engage the concavity formed in the preform, the other end of the support portion is fixed, and the one end of the support portion is urged outward.

Effects of the Invention

According to the transport apparatus of the present invention, the excellent effect can be exhibited that the preforms can be oriented in the same direction during continuous transportation.

MODE FOR CARRYING OUT THE INVENTION

A molding apparatus having a transport apparatus of the present invention will be described usingFIG. 1.

As shown inFIG. 1, a molding apparatus100provided with the transport apparatus according to the present embodiment is equipped with an injection molding section110for injection molding preforms200, which will become container bodies; a cooling section120for cooling the preforms200molded in the injection molding section110; a heating section130for heating the preforms200; and a blow molding section140for blow molding the preforms200arranged within blow cavity molds.

The molding apparatus100is also equipped with a transport section150including a transport line151constituting a loop-shaped transport line circulating from the cooling section120through the heating section130and the blow molding section140. The transport section150transports the preform200from the cooling section120to the heating section130, and also transports the preform200, which has been heated in the heating section130, to the blow molding section140.

The molding apparatus100according to the present invention is characterized by a transport apparatus300in the transport section150, and the configurations of the components will be described in detail below. Since the configurations of the injection molding section110, the cooling section120, the heating section130, and the blow molding section140are publicly known, they will be explained here briefly. (If necessary, reference is requested, for example, to WO2013/027692, the international publication by the present applicant.)

The injection molding section110is equipped with a mold clamping mechanism111, and clamps a core mold disposed above and a cavity mold disposed below by means of the mold clamping mechanism111, although their illustrations are omitted. In the injection molding section110, an injection space defined by the core mold and the cavity mold is charged with a resin material (raw material) by an injection device, whereby the preform200is injected molded. In the injection molding section110, assume, for example, that up to 24 (3 rows×8/row) of the preforms200can be molded simultaneously. In the present embodiment, the preform200has a thickness varying in the diametrical direction, and a concavity201(seeFIG. 2) is provided in its outer peripheral surface.

The cooling section120forcibly cools the injection molded preforms200. The preforms200injection molded in the injection molding section110are transported from the injection molding section110to the cooling section120by a transport unit (not shown), and forcedly cooled in the cooling section120. The preforms200cooled to a predetermined temperature in the cooling section120are carried out into the transport line151constituting the transport section150, and transported continuously.

The preforms200are molded in an upright state with the neck facing upward in the injection molding section110and, in this state, are transported from the injection molding section110to the cooling section120. The cooling section120has an inversion mechanism (not shown) for inverting the preforms200, which have been transported in such an upright state, to bring them into an inverted state with the neck facing downward. During cooling in the cooling section120, the preforms200are inverted by the inversion mechanism to enter an inverted state, and held by transport jigs152provided in the transport section150.

The transport line151is constituted such that these transport jigs152are transported continuously and sequentially by the driving force of a sprocket154, etc. Thus, the preforms200held by the transport jigs152are transported.

Below the cooling section120, these transport jigs152are arranged in a plurality of rows. The transport jigs152holding the preforms200are carried out into the transport line151. Then, the preforms200held by the transport jigs152are transported along the transport line151and carried into the heating section130.

In the heating section130, the preforms200cooled in the cooling section120are heated to a temperature suitable for stretching while the transport jigs152holding the preforms200are being moved along the transport line151. In the present embodiment, the preforms200are heated, while being allowed to rotate on their own axes, within the heating section130, whereby the preforms200are each heated uniformly as a whole.

After the preforms200are heated by the heating section130in the above manner, the transport line151has a curved transport portion155, which is curved with a predetermined radius, on a side downstream of the heating section130. The transport apparatus300is provided in correspondence with the curved transport portion155. The transport apparatus300, as will be described in detail later, is designed to set all the orientations of the preforms200during transportation to a predetermined orientation. Hence, the preforms200having passed through the curved transport portion155are all aligned in a state facing in a predetermined direction. Then, the transport jigs152holding the preforms200are transported from the curved transport portion155along the transport line151, and carried into the blow molding section140.

In a transfer section160, the preforms200, held in an inverted state, are inverted and taken out in an upright state, by predetermined numbers (for example, eights), by transfer arms (not shown). In the blow molding section140, the predetermined number of the preforms200received from the transfer section160are transported to blow cavity molds141each composed of a pair of split molds, and the preforms200are blow molded in the blow cavity molds141. In this case, with the present embodiment, the presence of the transport apparatus300to be described below makes it possible to align the orientations of the preforms with different thicknesses in the diametrical direction, thus enabling desired blow molding.

The transport apparatus300in the present embodiment will be described usingFIGS. 2 to 5.FIG. 2is a partially enlarged view of a site near the curved transport portion shown inFIG. 1for illustrating the transport apparatus.FIG. 3isFIG. 2from which the preforms have been eliminated for illustrating the transport apparatus.

The transport apparatus300provided in correspondence with the curved transport portion155is equipped with an engaging apparatus301for setting all of the orientations of the preforms200, which are being transported, to a predetermined orientation. The engaging apparatus301has a plurality of engaging devices310which engage the preforms200being transported along the transport line151, and set the orientations of the preforms200to the predetermined orientation. The transport apparatus300in the present invention is composed of such a transport line151, a transport device that transports the transport jigs152on the transport line151, and the plurality of engaging devices310.

The engaging apparatus301has a pedestal portion303which is formed in correspondence with the curved transport portion155and which has a curved part302curved in correspondence with the curved part of the curved transport portion155. A columnar portion304is provided in the pedestal portion303. The columnar portion304is configured to be capable of rotating on its axis in the horizontal direction, with its center as the axial center. The direction of this rotation of the columnar portion304on the axis thereof is set to be the same as the transport direction. That is, this direction is counterclockwise inFIGS. 2, 3 and 5. To the columnar portion304, the respective engaging devices310are fixed in a state in which they are separated from each other by a predetermined distance. Since the columnar portion304is of a polygonal shape, which can be a nearly circular shape, in a plan view, the respective engaging devices310can be said to be provided at a predetermined spacing in a circumferential direction.

Moreover, the pedestal portion303has a nearly circular groove part305formed in a plan view. The groove part305has a cam structure. As will be described in detail later, a rolling member314of the engaging device310is inserted into the groove part305. The groove part305has, at a predetermined position, a retreat area306which is recessed toward the columnar portion304, namely, inwardly.

The engaging device310will be described usingFIG. 4.

Each engaging device310has a first support portion312. The first support portion312is a U-shaped member in a side view. In a bottom surface part313constituting the bottom surface of the first support portion312, the rolling member314such as a cam follower is provided to extend vertically downwardly. The rolling member314is fastened in the bottom surface part313by a fastening member315. The rolling member314is inserted into the groove part305(seeFIG. 2) having the cam structure, as has been mentioned above.

A second support portion317is provided above an upper surface part316constituting the upper surface of the first support portion312. An engaging portion319is provided at the leading end318, beside the transport line151(seeFIGS. 2, 3), of the second support portion317. The engaging portion319is in a so-called cantilever state in which one end thereof is supported by the leading end318, while the other end thereof is not supported. The other end of the engaging portion is urged outward (toward the side opposite to the second support portion317).

The other end of the engaging portion319defines a protrusion320protruding toward the transport line151(seeFIGS. 2, 3). The protrusion320is in a shape corresponding to the concavity201(seeFIG. 2) as will be described later in detail. The protrusion320of the engaging portion319is configured to be associated with the transport line151in a region opposing the transport line151(seeFIG. 3).

In each engaging device310, two through-holes322are formed in a back surface part321constituting a part of the first support portion312between the bottom surface part313and the upper surface part316, and two cylindrical portions323are provided to penetrate the through-holes322. The base end side (at least one of the ends) of each cylindrical portion323is fixed to the columnar portion304(seeFIGS. 2, 3), and a plate-shaped portion324spanning the cylindrical portions323is fixed to the leading end side of each cylindrical portion323.

Returning toFIGS. 2, 3, the predetermined distance between the engaging device310provided on the columnar portion304agrees with the distance between the transport jigs152, namely, the distance between the preforms200.

The operating state of the transport apparatus300in the above configuration will be described below.

When the columnar portion304begins to rotate on its axis, with the center of the columnar portion304as the axial center (the direction of rotation on the axis is indicated by arrows inFIGS. 2, 3), each engaging device310moves along the groove part305in accordance with the rotation of the columnar portion304on its axis. This is because each engaging device310is fixed to the columnar portion304by the cylindrical portions323, and the rolling member314is inserted into the groove part305. That is, the groove part305functions as a guide groove for the engaging device310. Since the groove part305has, at the predetermined position, the retreat area306recessed toward the columnar portion304(inwardly), the engaging310, when coming to the retreat area306, retreats inside along the shape of the retreat area306. Past the retreat area306, the engaging device310moves again along the nearly circular groove part305.

The preform200to be transported in the transport direction (indicated by the arrows inFIGS. 2, 3) near the curved transport portion155will be described on the other hand. The transport speed of the preform200and the rotational speed of the columnar portion304agree with each other, and the distance between the preforms200and the distance between the engaging devices310, in the curved part302, are in agreement. In the curved part302, therefore, the engaging device310and the preform200always move while opposing each other. Such movement of the preform200and that of the engaging device310are performed in matched timing.

Around the pedestal portion303, the transport jig152rotates on its axis in the horizontal direction, with its center as the axial center, during transport. Concretely, for example, a sprocket provided in the transport jig152is fitted to a roller chain provided in the transport line151, whereby the transport jig152rotates on its axis. Also, the preform200placed thereon rotates on its axis in accordance with the rotation of the transport jig152on the axis thereof. When the preform200engages the engaging device310, the preform200does not rotate, but only the transport jig152rotates on its axis while being transported, as will be described later.

The position at which the rotation on one's own axis in the transport direction of the transport line151starts is designated as a self-rotation start position R1, while the position at which the rotation on one's own axis in the transport direction of the transport line151ends is designated as a self-rotation end position R2. A region ranging from the self-rotation start position R1to the self-rotation end position R2is designated as a self-rotation region RR. In the present embodiment, the self-rotation region RR terminates upstream, in the transport direction, of the position opposing the retreat area306. In the above configuration, for example, in which the sprocket provided in the transport jig152is fitted to the roller chain provided in the transport line151, whereby the transport jig152rotates on its axis, it follows that the roller chain is provided throughout the self-rotation region RR. The self-rotation region RR is set such that the preform200can make at least one rotation from the self-rotation start position R1until the self-rotation end position R2, unless the preform200engages the engaging device310.

As shown inFIG. 2, when the preform200is transported to a site near the curved transport portion155, the positions of the concavities201face in different directions (unaligned state), and the orientations of the preforms200are certainly nonuniform. In such a state, the preforms200are transported, and flow into the self-rotation region RR. In the self-rotation region RR, the preform200is transported while being allowed to rotate on its axis. While the preform200is being transported in the transport line151while being caused to rotate on its axis, in the manner mentioned above, the protrusion320of the engaging device310is fitted into the concavity201provided in the preform200. Upon fitting of the protrusion320into the concavity201, only the transport jig152rotates on its axis, as mentioned above, and the rotation of the preform200stops because of the fitting.

When the preform200is carried out of the self-rotation region RR, the engaging device310retreats into the retreat area306at the same time. Thus, the engaging portion319, i.e. the protrusion320, disengages from the preform200, and the preform200is transported in this state. That is, the preforms200located downstream, in the transport direction, of the position corresponding to the retreat area306are all transported, with the concavities201being aligned in the same orientation (aligned state).

In this connection, a further concrete explanation will be presented usingFIG. 5.FIG. 5shows the transport state of the single preform200in the curved transport portion155, and shows the transport position of the preform200at each elapsed time, and the single engaging device310opposing and engaging the preform200. In detail,FIG. 5describes a plurality of the preforms200and a plurality of the engaging device310, but all of them represent the same preform200and the same engaging device310at their respective positions at respective elapsed times.

As stated above, the preform200is transported to the curved transport portion155from its upstream side. In harmony with the transport of the preform200, the engaging device310is also moved along the groove part305. At a time t1, the preform200is transported to a site immediately in front of the self-rotation start position R1of the curved transport portion155. The preform200(t1) at the time t1has the concavity201facing outward. In this case, the engaging device310(t1) does not yet oppose the preform200(t1).

When the preform200arrives at the self-rotation start position R1, the transport jig152(seeFIG. 2) begins to rotate on its axis, beginning at the self-rotation start position R1, so that the preform200also begins to rotate on its axis. The direction of the rotation on the axis is the direction indicated by the arrow. In the self-rotation region RR, the preform200is transported while rotating on its axis. The preform200(t2) at a time t2in the vicinity of the self-rotation start position R1does not yet oppose the engaging device310(t2) at this point in time.

The preform200is further transported and, at a time t3, the preform200(t2) opposes the engaging device310(t3). In this case, the protrusion320of the engaging device310is not in engagement with the concavity201of the preform200(t3), and is thus pressed by the preform200(t3) and remains retracted.

Then, the preform200(t3) continues to rotate on its axis while being transported. The engaging device310(t3), keeping opposed to this preform200, moves, with the protrusion320being pressed by the preform200. At a time t4, the concavity201of the preform200(t4) faces completely inward, and engages the protrusion320of the engaging device310(t4).

That is, in the present embodiment, the preform200rotates on its axis in the self-rotation region RR. Consequently, no matter which position the preform200faces when reaching the curved transport portion155during transport, the concavity201of the preform200engages the engaging portion319of the engaging device310, without fail.

Since the engaging device310moves along the groove part305, the engaging device310, at the time t4, retreats in the retreat area306. As a result, the engaging portion319of the engaging device310separates from the concavity201of the preform200being transported, thus completing the engagement. In this case, the preform200being transported simultaneously can be transported, with its orientation being unchanged.

Should the groove part305lack the retreat area306, the protrusion320is caught in the concavity201of the preform200when the protrusion320separates from the concavity201. As a result, the preform200rotates, and the orientation of the preform200changes. In this case, it is difficult to align the orientations of the preforms200, which have passed through the curved transport portion155, with the same direction, as shown inFIG. 2. Thus, it is desirable that the retreat area306be formed in the groove part305to prevent the protrusion320from getting snagged when it disengages from the concavity201, as in the present embodiment.

In this manner, the preforms200finishing the engagement are transported with their orientations being aligned.

In the present embodiment, the preforms200are transported, with their orientations being aligned, as described above. Thus, when the preforms200are carried into the blow molding section140, too, their orientations are in alignment. Consequently, even if the shape of the preform200is not uniform in the diametrical direction of the preform200, for example, even in the case of an elliptical shape or a nonuniform thickness, the orientations of all the preforms200are aligned, so that the preforms200can be subjected to desired blow molding in the blow molding section140.

In the present embodiment, moreover, the engaging portion319has one end supported by the leading end318, and has the other end urged outward without being supported. Thus, the engaging portion319easily engages the concavity201of the preform200.

According to the foregoing transport apparatus300, the orientation of each preform200can be aligned with the same orientation during continuous transport.

The present invention is not limited to the above-described embodiment. In the present embodiment, for example, the curved transport portion155is provided between the heating section130and the blow molding section140, but the arrangement of the curved transport portion155is not limited thereto. For example, the curved transport portion155may be provided ahead of the heating section130.

The present embodiment illustrates the configuration in which the protrusion320of the engaging device310engages the concavity201formed in the preform200, but the configuration for engagement of the engaging device310with the preform200is not limited. For example, a convexity may be formed in the preform200, and this convexity may be pressed against a convexity formed in the engaging portion319to perform engagement.

In the present embodiment, an explanation is offered for the example in which the transport apparatus300continuously transports only the preforms200. However, the configuration of the transport apparatus is not limited thereto. In forming handle-equipped containers, for example, the transport apparatus may be configured to alternately transport preforms and handles for bottles.

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