Rotary molding machine

Abstract

DEPCT65 The easily manufactured rotary forming machine with this invention is presented as a rotary forming machine. It consists of the first and second molds, the camshaft, and the cam orbital parts. A rotary forming machine in which the first and second dies and the camshaft are assembled. Rotating with its axis of rotation as the center, such a cam orbital segment has a cam orbital axis. The aforementioned cam will move to follow the cam orbit according to the rotation of the first mold. The second type opens and closes according to the movement of the cam axis, the angle between those axis directions. At the time the first and second molds were closed, and the axial direction was the same as at the time the first mold was opened. And secondly, the maximum is no more than 45 degrees when given the direction along the longitudinal axis of the camshaft. That is the axial direction. -----------------------------------------------------------

Description

Rotary Molding Machine

[0001] The present invention relates to a rotary molding machine.

[0002] In the rotary molding machines of Patent Documents 1 and 2, a pair of molds are opened and closed while revolving, thereby supplying a parison between the pair of molds, molding the parison, and removing the molded body.

[0003] (First Aspect) In Patent Document 1, the pair of molds are opened and closed by moving a cam roller, which is held by a connecting rod that is integral with one of the pair of molds, along a cam track.

[0004] (Second Aspect) The rotary molding machine of Patent Document 2 includes a boost member and a guide member. The boost member has the function of removing the molded body from the mold by rotating around its axis, and is rotatably attached to the mold. The guide member has the function of rotating the boost member, and is attached to the rotary molding machine. The boost member comes into contact with the guide member as the mold revolves. As a result, the boost member is rotated by the guide member, and the molded body is pushed up from the mold.

[0005] Japanese Unexamined Patent Publication No. 11-333915 Publication of Utility Model Application No. 61-047619

[0006] (First Aspect) In Patent Document 1, the angle between the direction of the connecting rod when the pair of dies are closed and the direction of the connecting rod when the pair of dies are fully open is 90 degrees or more. This requires a very large three-dimensional displacement of the cam track, and it is extremely difficult to manufacture a rail that realizes such a cam track.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a rotary molding machine that is easy to manufacture.

[0008] (Second Aspect) In Patent Document 2, when the boost member is in contact with the guide member, the boost member gradually rotates along the surface of the guide member. On the other hand, when the boost member passes through the guide member and is out of contact with the guide member, the boost member can rotate freely. For this reason, in the rotary molding machine of Patent Document 2, the boost member may dangle in the stage prior to molding of the molded body, causing the parison on the mold to move, resulting in the parison being displaced from the desired position and preventing the molded body from being molded into the desired shape.

[0009] The present invention has been made in view of the above circumstances, and has as its object to provide a rotary molding machine that can more reliably mold a molded article having a desired shape.

[0010] (First Aspect) According to the present invention, there is provided a rotary molding machine comprising first and second molds, a cam shaft, and a cam track member, wherein the first and second molds and the cam shaft are configured to rotate around an axis of revolution, the cam track member has a cam track, the cam shaft moves along the cam track as the cam shaft rotates, the first and second molds open and close as the cam shaft moves, and when the longitudinal direction of the cam shaft is taken as the axial direction, the angle between the axial direction when the first and second molds are closed and the axial direction when the first and second molds are fully open is 45 degrees or less.

[0011] In the present invention, the angle between the axial direction of the camshaft when the first and second molds are closed and the axial direction of the camshaft when the first and second molds are fully open is 45 degrees or less. Therefore, the three-dimensional displacement of the cam path is smaller than in Patent Document 1, and achieving such a cam path is easier than in Patent Document 1. Therefore, according to the present invention, a rotary molding machine that is easy to manufacture is provided.

[0012] Various embodiments of the present invention are exemplified below. The embodiments described below can be combined with each other. Preferably, the rotary molding machine described above is a rotary molding machine in which the cam track is configured so that the distance from the revolution axis changes along the circumferential direction. Preferably, the rotary molding machine described above is a rotary molding machine in which the cam track member has a base plate, and the cam track is configured by an annular groove or annular protrusion provided on the base plate. Preferably, the rotary molding machine described above is a rotary molding machine in which the first and second molds are connected by a hinge portion, and the first and second molds are opened and closed by relative rotation about the hinge portion. Preferably, the rotary molding machine described above is a rotary molding machine in which movement of the cam shaft is transmitted via a gear mechanism to open and close the first and second molds. Preferably, the rotary molding machine described above is a rotary molding machine in which the gear mechanism is a mechanism that converts linear movement into rotational movement. Preferably, in the rotary molding machine described above, the revolution axis forms an angle of 45 degrees or less with respect to a horizontal plane.

[0013] (Second Aspect) According to the present invention, there is provided a rotary molding machine comprising first and second molds, a boost member, and a drive mechanism, wherein the second mold is configured to be openable and closable relative to the first mold, the boost member is provided on the first mold and has a boost section, the boost section is configured to be movable from a first position to a second position, and the molded body on the first mold is pushed up by the boost section moving from the first position to the second position, the second position being farther away from the first mold than the first position, the drive mechanism having an engagement member and a drive section, the engagement member engaging with the boost member at the first and second positions, and the drive section driving the engagement member so that the boost section can move from the first position to the second position.

[0014] In the present invention, since the engaging member engages with the boost member at both the first and second positions, it is possible to prevent the boost member from wobbling at either the first or second position. In other words, in the present invention, wobbling of the boost member is prevented in the pre-molding stage of the molded body, making it possible to more reliably mold a molded body of the desired shape.

[0015] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other. Preferably, the boost member further includes a contact portion and a pivotal support portion, the boost member being provided on one side of the boost member and the contact portion being provided on the other side of the boost member, the pivotal support portion being provided between the boost member and the contact portion and pivotally supported by the first mold, and the drive portion moving the engaging member in a linear direction. Preferably, the drive portion includes an air cylinder and a piston, the piston being attached to the air cylinder and connected to the engaging member. Preferably, the rotary molding machine further includes an air supply portion configured to supply air into a parison that constitutes the molded product, the boost member being disposed opposite the air supply portion, and the tip of the boost member being configured to branch into two branches. Preferably, there is provided a rotary molding machine further comprising a base portion, the base portion being configured to be rotatable about an axis, and the first mold being fixed to the base portion.

[0016] 3A is a front view of a rotary molding machine 1 according to an embodiment of the first aspect of the present invention. FIG. 3B is a left side view of the mold unit 3 when the mold unit 3 is located between positions P1 and P2. FIG. 3A is a left side view of the mold unit 3 when the mold unit 3 is located between positions P1 and P2. FIG. 3B is a left side view of the mold unit 3 when the mold unit 3 is located between positions P2. FIG. 3B is a perspective view of a state in which the cylindrical portion 3h1 of the cam shaft 3h is disposed in the annular groove 5b of the cam track member 5. FIG. 3C is a front view of a state in which the cam shafts 3h of 15 mold units 3 are disposed in the annular groove 5b of the cam track member 5. FIG. 3D is a perspective view of a rotary molding machine 1 according to an embodiment of the second aspect of the present invention. FIG. 7 shows a state in which a portion (within a 90-degree range) of the plate-shaped member 12C is cut away for ease of explanation. FIG. 7 is a front view of the rotary molding machine 1 (base portion 2, mold unit 3, and extrusion head 4), parison 8, and molded body 9 shown in FIG. 7 shows a state in which the mold unit 3 is fully open. 9 shows a state in which the mold unit 3 is in a position P1 from position P4 shown in FIG. 5, and the push-up mechanism 7 is in a pressed-down state. FIG. 9 is a perspective view of the mold unit 3 seen from a direction different from that shown in FIG. 9. FIG. 9 shows a state in which the mold unit 3 shown in FIG. 9 is fully closed. FIG. 11 shows a state in which the mold unit 3 is in a position P3 from position P2 shown in FIG. 5. FIG. 11 is a perspective view showing a state in which the push-up mechanism 7 of the mold unit 3 shown in FIG. 9 is in a pressed-up state. FIG. 12 is an enlarged view of region A shown in FIG. 12. FIG. 16A is an enlarged view of region A shown in FIG. 9, and FIG. 16B is an enlarged view of region B shown in FIG. 12.

[0017] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0018] 1 to 5, a rotary molding machine 1 according to one embodiment of the present invention includes a base portion (annular base) 2, a plurality of mold units 3, an extrusion head 4, and a cam track member 5. In this embodiment, 15 mold units 3 are arranged at equal intervals around the circumferential direction of the base portion 2.

[0019] 2, each mold unit 3 includes a support 3a, a first mold (fixed mold) 3b, a second mold (movable mold) 3c, a hinge portion 3d, a pinion gear 3e, a rack gear 3f, a support wall 3g, and a camshaft 3h. The camshaft 3h includes a cylindrical portion 3h1 and a shaft portion 3h2.

[0020] The support pillars 3a and the support walls 3g are fixed to the base portion 2. The first mold 3b is fixed to the support pillars 3a. The second mold 3c is fixed to the first mold 3b via a hinge portion 3d. Therefore, the first mold 3b and the second mold 3c can be opened and closed by rotating the second mold 3c around the hinge portion 3d.

[0021] The pinion gear 3e is fixed to the second mold 3c, and the second mold 3c can be rotated by rotating the pinion gear 3e around the hinge portion 3d. The rack gear 3f is connected to the support wall 3g via a linear guide (not shown). A shaft portion 3h2 is fixed to the rack gear 3f. The shaft portion 3h2 is fixed to the cylindrical portion 3h1 via a bearing.

[0022] 2 shows the molds 3b and 3c in the fully open state, FIG. 3A shows the molds 3b and 3c in the middle of being closed, and FIG. 3B shows the molds 3b and 3c in the state after being closed.

[0023] When the cylindrical portion 3h1 rises from the state shown in Fig. 2, the shaft portion 3h2 and rack gear 3f also rise. As the rack gear 3f rises, the pinion gear 3e and second mold 3c rotate clockwise, resulting in the state shown in Fig. 3A. When the cylindrical portion 3h1 is further raised, the second mold 3c rotates further clockwise, resulting in the state shown in Fig. 3B.

[0024] When the cylindrical portion 3h1 descends from the state shown in Fig. 3B, the shaft portion 3h2 and rack gear 3f also descend. As the rack gear 3f descends, the pinion gear 3e and second mold 3c rotate counterclockwise, resulting in the state shown in Fig. 3A. When the cylindrical portion 3h1 is further descended, the second mold 3c further rotates counterclockwise, resulting in the state shown in Fig. 2.

[0025] In this way, the gear mechanism formed by the rack gear 3 f and pinion gear 3 e converts the linear movement of the cam shaft 3 h into the rotational movement of the mold 3 c, thereby opening and closing the molds 3 b and 3 c. Note that the gear mechanism may be another mechanism that can convert linear movement into rotational movement.

[0026] In this way, the molds 3b and 3c can be opened and closed by moving the cylindrical portion 3h1 in parallel in the vertical direction.

[0027] The base part 2 is rotatable about the revolution axis C by a rotation drive mechanism (not shown). The mold unit 3 also rotates in accordance with the rotation of the base part 2. Therefore, in accordance with the rotation of the base part 2, the molds 3b, 3c and the cam shaft 3h rotate about the revolution axis C. In FIG. 1, the base part 2 rotates clockwise.

[0028] As shown in Figures 4 and 5, the cam track member 5 has a base plate 5a, and an annular groove 5b is provided in the base plate 5a. The annular groove 5b defines a cam track 5c. The cylindrical portion 3h1 of the cam shaft 3h is disposed within the annular groove 5b. As the base portion 2 rotates, the cylindrical portion 3h1 moves along the annular groove 5b (cam track 5c), causing the cam shaft 3h and rack gear 3f to move along the annular groove 5b (cam track 5c). Because the cam track 5c is provided on the base plate 5a, the timing of opening and closing the molds 3b and 3c can be easily changed by rotating the base plate 5a about the revolution axis C.

[0029] As shown in Figure 5, the cam track 5c is configured so that the distance D from the revolution axis C changes along the circumferential direction. If the distances from the revolution axis C to the inner peripheral surface of the cam track 5c at positions P1 and P2 are D1 and D2, respectively, the following can be said: - The distance D is smallest (D1) at position P1. - The distance D gradually increases from position P1 to P2. - The distance D is constant (D2) between positions P2 and P3. - The distance D gradually decreases from position P3 to P4. - The distance D is constant (D1) between positions P4 and P1.

[0030] Since the cam shaft 3h moves along the cam track 5c, an increase or decrease in the distance D corresponds to the elevation of the cam shaft 3h in Figures 2 and 3. Therefore, the cam shaft 3h moves along the cam track 5c, thereby opening and closing the molds 3b and 3c.

[0031] The opening and closing operations of the molds 3b and 3c are as follows: At position P1, the molds 3b and 3c are in the most open state. As they move from position P1 to P2, the molds 3b and 3c gradually close. Between positions P2 and P3, the molds 3b and 3c are closed. As they move from position P3 to P4, the molds 3b and 3c gradually open. Between positions P4 and P1, the molds 3b and 3c are in the most open state.

[0032] As shown in Figure 4, the side surface 5b1 of the annular groove 5b is perpendicular to the main surface of the base plate 5a, and the camshaft 3h moves while the outer peripheral surface of the cylindrical portion 3h1 abuts against the side surface 5b1 of the annular groove 5b. Therefore, the camshaft 3h moves parallel to the axial direction (longitudinal direction) X without changing. If the axial directions at positions P1 and P2 are X1 and X2, respectively, the angle between the axial direction X2 when the molds 3b and 3c are closed (at position P2) and the axial direction X1 when the molds 3b and 3c are fully open (at position P1) is 0 degrees. The axial direction of the camshaft 3h coincides with the direction of the central axis of the cylindrical portion 3h1.

[0033] It is also possible to change the axial direction X of the camshaft 3h by inclining the side surface of the annular groove 5b. However, if the change in the axial direction X is large, it becomes difficult to form the cam track 5c and the operation of the camshaft 3h tends to become unstable. Therefore, it is preferable that the angle between the axial directions X1 and X2 is 45 degrees or less. Specific examples of this angle are 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees, and it may be within a range between any two of the values ​​exemplified here.

[0034] In this embodiment, the revolution axis C is parallel to the horizontal plane, which makes it easy to insert the parison 8 between the molds 3b and 3c from the extrusion head 4 installed above the rotary molding machine 1. The parison 8 is formed from molten resin and is preferably cylindrical, but may also be sheet-shaped. The direction in which the parison 8 is inserted is preferably tangent to the rotation path of the molds 3b and 3c. The angle of the revolution axis C with respect to the horizontal plane is preferably 45 degrees or less, and specifically may be, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, or 45 degrees, or may be within a range between any two of the values ​​exemplified here.

[0035] 2. Rotary Molding Method Rotary molding can be performed using the rotary molding machine 1.

[0036] A rotary molding method according to one embodiment of the present invention includes a parison injection step, a molding step, and a removal step.

[0037] In the parison injection process, the parison 8 extruded from the extrusion head 4 is injected between the open molds 3b and 3c. The molds 3b and 3c are most open between positions P4 and P1 and then gradually close as they move from position P1 to P2. This allows the parison 8 to be injected between the molds 3b and 3c at any desired position between positions P4 and P2. However, if the parison 8 is injected near position P4, the extrusion head 4 and parison 8 are likely to interfere with the molded body 9. If the parison 8 is injected near position P2, the parison 8 is likely to interfere with the molds 3b and 3c. Therefore, the parison injection process is preferably performed between position P41, which is the center between positions P4 and P1, and position P12, which is the center between positions P1 and P2.

[0038] In the molding step, the parison 8 is molded using the molds 3b and 3c. When the molds 3b and 3c are closed, the cavity formed therein has a shape corresponding to the outer shape of the molded body 9, so that the molded body 9 can be formed by molding using the molds 3b and 3c. The molding may be blow molding or vacuum molding.

[0039] In the ejection process, the molded body 9 is ejected from the open molds 3b and 3c. The molds 3b and 3c gradually open from position P3 to P4, then reach their most open state between positions P4 and P1. Therefore, the molded body 9 can be ejected at any desired position between positions P3 and P1. However, if the molded body 9 is ejected at a position close to position P3, it is likely to interfere with the molds 3b and 3c. If the molded body 9 is ejected at a position close to position P1, it is likely to interfere with the extrusion head 4 or the parison 8. Therefore, the ejection process is preferably performed between position P34, which is the center between positions P3 and P4, and position P41, which is the center between positions P4 and P1. Furthermore, to avoid interference between the molds 3b and 3c, the molded body 9, and the ejection device, it is preferable to eject the molded body 9 after the molds 3b and 3c are fully open. Therefore, the ejection process is preferably performed between positions P4 and P1, and more preferably between positions P4 and P41.

[0040] 3. Other Embodiments In the above embodiment, the cam track 5c is formed by the annular groove 5b. However, the cam track 5c may also be formed by an annular protrusion provided on the base plate 5a. As shown in FIG. 6, the cam track 5c may also be formed by a rail 13. The dies 3b, 3c may be configured to open and close by rotating both dies 3b, 3c. The dies 3b, 3c may be configured to open and close by moving toward and away from each other in parallel. The cam shaft 3h may be directly connected to the dies. The dies 3b, 3c may be configured to open and close at a constant speed, or the opening and closing speed may be variable. For example, the closing speed of the dies 3b, 3c may gradually increase as the dies 3b, 3c move from position P1 to position P2. This makes it easier to avoid interference between the parison 8 and the die 3c. The opening and closing speed of the dies 3b, 3c can be adjusted by changing the cam track 5c.

[0041] (Second Viewpoint) 1. Configuration and Operation of Rotary Molding Machine 1 As shown in Fig. 7 , the rotary molding machine 1 of this embodiment includes a base 2, a plurality of mold units 3, an extrusion head 4 (see Fig. 8 ), a cam track member 5, a power mechanism 10, a shaft 11, and a switch mechanism 12. In this embodiment, 15 mold units 3 are arranged at equal intervals around the circumferential direction of the base 2.

[0042] 1-2. Base portion 2 The base portion 2 is connected to the shaft 11, and rotates about its axis as the shaft 11 rotates. In FIG. 7, the direction of rotation of the base portion 2 is indicated by an arrow AR1. A plurality of mold units 3 (15 in this embodiment) are attached to the circumferential surface of the base portion 2. As the base portion 2 rotates, each mold unit 3 revolves around the revolution axis C. The base portion 2 is disposed between the cam track member 5 and the switch mechanism 12.

[0043] 9 and 10, each mold unit 3 includes a support 3a (see FIGS. 7 and 8), a first mold (fixed mold) 3b, a second mold (movable mold) 3c, a hinge portion 3d, a pinion gear 3e, a rack gear 3f, a linear guide 3ft, a support wall 3g, a cam shaft 3h, an air supply portion 6, and a push-up mechanism 7.

[0044] 1-3-1. Support pillar 3a and support wall 3g As shown in Figures 7 and 8, the support pillar 3a is fixed to the base portion 2. The first mold 3b is fixed to the support pillar 3a. Note that the support pillar 3a is not shown in Figures 9 to 12. The support wall 3g is also fixed to the base portion 2, similar to the support pillar 3a. The support wall 3g is a plate-like member formed to extend in the radial direction of the base portion 2. A linear slit 3g1 is formed in the support wall 3g. In this embodiment, two rows of slits 3g1 parallel to each other are formed in the support wall 3g. A camshaft 3h (a shaft portion 3h2 described later) is inserted into the slit 3g1.

[0045] 1-3-2. First and Second Molds 3b, 3c As shown in FIGS. 9 and 10, the first mold 3b is provided with a push-up mechanism 7 and an air supply unit 6. In the embodiment, the push-up mechanism 7 is fixed to the first mold 3b, but this is not limited to this configuration. The push-up mechanism 7 may be fixed to the base unit 2, for example. The first mold 3b includes a first storage portion 3b1 and a first cavity member 3b2. The first storage portion 3b1 is configured to accommodate the first cavity member 3b2. The first storage portion 3b1 includes first and second arrangement portions 3bt, 3bs, and the first arrangement portion 3bt and the second arrangement portion 3bs are separated by the first cavity member 3b2. The first cavity member 3b2 is accommodated in the first storage portion 3b1, and a recess corresponding to the shape of the molded body 9 is formed in the first cavity member 3b2. The first mold 3b is formed with a groove 3b11 (see FIG. 13) in which a boost member 7A of the boost mechanism 7, which will be described later, is disposed. The first mold 3b is also provided with a shaft 3b12 that rotatably supports the boost member 7A. Note that, although the shaft 3b12 is provided on the first mold 3b in the embodiment, the present invention is not limited to this, and the shaft 3b12 may not be provided on the first mold 3b but may be provided adjacent to the first mold 3b.

[0046] The second mold 3c includes a second housing portion 3c1 and a second cavity member 3c2. The second housing portion 3c1 is configured so that the second cavity member 3c2 can be placed therein. The second cavity member 3c2 is housed in the second housing portion 3c1, and a recess corresponding to the shape of the molded body 9 is formed in the second cavity member 3c2.

[0047] 1-3-3. Hinge portion 3d and pinion gear 3e As shown in Figures 9 and 10, the hinge portion 3d is configured to allow the second mold 3c to rotate relative to the first mold 3b. The second mold 3c is provided on the first mold 3b via the hinge portion 3d so that it can be opened and closed. The first mold 3b and the second mold 3c can be opened and closed by the second mold 3c rotating around the hinge portion 3d. The pinion gear 3e is fixed to the second mold 3c. The rotation of the pinion gear 3e around the hinge portion 3d rotates the second mold 3c, and the first and second molds 3b, 3c open (see Figure 9) or close (see Figure 11).

[0048] 9 and 10, the rack gear 3f engages with the pinion gear 3e, and the rack gear 3f is connected to the linear guide 3ft. The linear guide 3ft is attached to the support wall 3g so as to be movable along the surface of the support wall 3g. A camshaft 3h is fixed to the linear guide 3ft.

[0049] 1-3-5. Camshaft 3h As shown in FIG. 10, the camshaft 3h includes a cylindrical portion 3h1 and a shaft portion 3h2. The cylindrical portion 3h1 is provided on one side of the shaft portion 3h2. The cylindrical portion 3h1 is connected to the shaft portion 3h2 via a bearing. The cylindrical portion 3h1 is inserted into a cam track 5c (see FIG. 4) formed in the cam track member 5. The shaft portion 3h2 passes through a slit 3g1. As shown in FIGS. 9 and 10, the cylindrical portion 3h1 is provided on one side of the shaft portion 3h2, and a linear guide 3ft is provided on the other side of the shaft portion 3h2. The shaft portion 3h2 is fixed to the linear guide 3ft. The linear guide 3ft moves in accordance with the movement of the cylindrical portion 3h1, which in turn rotates the pinion gear 3e and the second mold 3c.

[0050] 9, the air supply unit 6 is provided in the first mold 3b. During molding, the air supply unit 6 penetrates the parison, and air is blown into the parison from the air supply unit 6. This causes the parison to expand and be molded into the desired shape.

[0051] 1-3-7. Push-up mechanism 7 The push-up mechanism 7 includes a push-up member 7A and a drive mechanism. The drive mechanism of the push-up mechanism 7 includes a drive unit 7B and an engagement member 7C.

[0052] 1-3-7-1. Boost Member 7A As shown in FIGS. 9 and 12, the boost member 7A is a rod-shaped member and includes a boost portion 7A1, a pivot support portion 7A2, and a contact portion 7A3. The rotation direction of the boost member 7A is the same as the opening direction of the first and second molds 3b, 3c (the rotation direction of the second mold 3c). Here, the air supply unit 6 described above is provided in the second arrangement portion 3bs of the first housing portion 3b1 of the first mold 3b, while the boost member 7A is provided in the first arrangement portion 3bt of the first housing portion 3b1 of the first mold 3b. In other words, the boost member 7A is not provided on the side where the air supply unit 6 is provided, but is provided so as to face the air supply unit 6 in the direction from the first arrangement portion 3bt toward the second arrangement portion 3bs.

[0053] As shown in Figures 9, 10, 12, and 13, the push-up section 7A1 is provided on one side (one end side) of the push-up member 7A. The push-up section 7A1 is movable from a first position to a second position, which will be described later. When the push-up section 7A1 moves from the first position to the second position, the molded body is pushed up. When the push-up section 7A1 moves from the second position to the first position, the parison can be placed again on the first mold 3b.

[0054] The first position in this embodiment is the position of the push-up part 7A1 when it has descended to its lowest point, as shown in Figures 9 and 10. The second position in this embodiment is the position of the push-up part 7A1 when it has ascended to its highest point, as shown in Figure 13. The second position is a position that is farther away from the first mold 3b than the first position.

[0055] The first position is not limited to the position of the push-up part 7A1 when it has descended to its lowest point. The second position is not limited to the position of the push-up part 7A1 when it has ascended to its highest point. The second position may be any position that is farther from the first mold 3b than the first position.

[0056] As shown in FIGS. 14 and 15 , the booster 7A1 is positioned opposite the air supply unit 6. The air supply unit 6 is also movable in the forward and backward directions, as indicated by the arrow AR2 in FIG. 15 . When the booster 7A1 moves from the first position to the second position or from the second position to the first position, if the air supply unit 6 moves forward, interference may occur between the booster 7A1 and the tip of the air supply unit 6. For example, a situation may arise in which the air supply unit 6 gets caught on the molded product, causing the air supply unit 6 to move rearward instead of clearing the booster 7A1 and remaining forward. In such a situation, when the booster 7A1 is driven, interference may occur between the booster 7A1 and the air supply unit 6. For this reason, in this embodiment, the tip of the booster 7A1 is configured to branch into two branches, as shown in FIG. 15 .

[0057] As shown in Figures 9 and 10, the axial support portion 7A2 is provided between the push-up portion 7A1 and the contact portion 7A3. The axial support portion 7A2 is axially supported by the first mold 3b. Specifically, as shown in Figures 12 and 13, the axial support portion 7A2 is connected to a shaft portion 3b12 provided on the first mold 3b, and the axial support portion 7A2 is rotatable around the shaft portion 3b12. If the entire axial support portion 7A2 protrudes from the groove portion 3b11 when the push-up portion 7A1 is located in the second position, the lower portion of the axial support portion 7A2 may come into contact with the wall surface of the groove 3b11 when the push-up portion 7A1 is descending, making it difficult for the axial support portion 7A2 to return to the groove 3b11. 13, when the push-up portion 7A1 is in the second position, at least a portion of the pivotal support portion 7A2 is contained within the groove portion 3b11 (see FIG. 13). This makes it possible to prevent the pivotal support portion 7A2 from becoming difficult to return to the groove portion 3b11.

[0058] Here, length x1 is defined as the longitudinal length of the boost member 7A from the tip of the boost portion 7A1 to the rotation axis of the axial support portion 7A2. The position of the rotation axis of the axial support portion 7A2 corresponds to the position where the shaft portion 3b12 is provided. Length x2 is defined as the longitudinal length of the boost member 7A from the rotation axis of the axial support portion 7A2 to the contact position of the contact portion 7A3. The contact position of the contact portion 7A3 is the position where the contact portion 7A3 contacts the first engagement portion 7C2 or the second engagement portion 7C3. In this embodiment, length x2 is longer than length x1. This allows the leverage principle to effectively act on the boost member 7A, thereby reducing the driving force required for the drive portion 7B.

[0059] As shown in FIGS. 16A and 16B , the contact portion 7A3 is provided on the other side of the boost member 7A. The contact portion 7A3 is a portion that contacts the engaging member 7C. The contact portion 7A3 moves as the engaging member 7C is driven (moved). In this embodiment, the contact portion 7A3 is not connected to the engaging member 7C. If the contact portion 7A3 were connected to the engaging member 7C, the drive unit 7B would need to include, for example, a mechanism for moving the engaging member 7C in an arc or a mechanism with a shaft connecting the engaging member 7C to the contact portion 7A3. In other words, if the contact portion 7A3 were connected to the engaging member 7C, the mechanisms of the drive unit 7B and the engaging member 7C would become more complex, resulting in increased costs for the rotary molding machine 1. Furthermore, the rotary molding machine 1 is an apparatus equipped with multiple mold units 3, and the gaps between each mold unit 3 are relatively narrow, making it difficult to secure space for arranging various components in the rotary molding machine 1. In the embodiment, the boost member 7A and the engaging member 7C are simply configured and are prevented from becoming large. This allows for easy attachment of multiple boost mechanisms 7 to the rotary molding machine 1. Furthermore, because the boost mechanism 7 is prevented from becoming large, the rotary molding machine 1 is also prevented from becoming large. In the embodiment, as described above, the contact portion 7A3 and the engaging member 7C are not connected to each other but are merely engaged with each other. Furthermore, in the embodiment, the boost portion 7A1 can be moved between the first position and the second position simply by linearly moving the engaging member 7C. Therefore, the embodiment allows for appropriate movement of the boost portion 7A1 while minimizing the complexity of the mechanism, minimizing the cost of the rotary molding machine 1, improving the ease of attachment of the boost mechanism 7, and minimizing the size of the rotary molding machine 1.

[0060] 1-3-7-2. Drive Unit 7B The drive unit 7B has a function of driving the engagement member 7C so that the push-up unit 7A1 can move from the first position to the second position. The drive unit 7B can be a hydraulic drive or a motor drive of the push-up member 7A, but in this embodiment, the drive unit 7B is a system that drives the push-up member 7A with air. This prevents oil contamination of the rotary molding machine 1, increases in the size and weight of the rotary molding machine 1, and the like.

[0061] 16A and 16B, the drive unit 7B includes an air cylinder 7B1 and a piston 7B2. The air cylinder 7B1 is fixed to the first mold 3b. Air is supplied to the air cylinder 7B1 from an air tube (not shown), and the air cylinder 7B1 has the function of moving the piston 7B2 in a linear direction. The piston 7B2 is connected to an engaging member 7C.

[0062] In the above-mentioned Patent Document 2, the guide member can rotate the lift-up member. However, in order for the lift-up member to properly lift up the molded product, the surface of the guide member must be formed with a three-dimensional, complex curved surface. Such a guide member has the problem of being extremely difficult to manufacture and of making it difficult to ensure the operational accuracy of the lift-up member. In the embodiment, a drive unit 7B is used instead of the guide member, thereby avoiding these problems.

[0063] 1-3-7-3. Engagement Member 7C As shown in Figures 16A and 16B, the engagement member 7C includes a frame 7C1 and first and second engagement portions 7C2 and 7C3. The frame 7C1 is connected to the piston 7B2 and is movable together with the piston 7B2. The engagement member 7C engages with the boost member 7A (contact portion 7A3) at the first and second positions. Specifically, the first engagement portion 7C2 is located farther from the air cylinder 7B1 than the second engagement portion 7C3. The boost member 7A (contact portion 7A3) is disposed between the first engagement portion 7C2 and the second engagement portion 7C3. The configuration and shape of the engagement member 7C can be modified as appropriate.

[0064] When the push-up portion 7A1 is located at the first position (see FIG. 9), the contact portion 7A3 engages with the second engagement portion 7C3 as shown in FIG. 16A. Therefore, movement of the contact portion 7A3 in the direction in which the contact portion 7A3 is pushed down is restricted. When the push-up portion 7A1 is located at the second position (see FIG. 12), the contact portion 7A3 engages with the first engagement portion 7C2 as shown in FIG. 16B. Therefore, movement of the contact portion 7A3 in the direction in which the contact portion 7A3 is pushed up is restricted.

[0065] In this way, in the rotary molding machine 1 according to the embodiment, the engaging member 7C engages with the boost member 7A at both the first and second positions, so that the swinging of the boost member 7A is suppressed at both the first and second positions. In other words, in the rotary molding machine 1 according to the embodiment, the swinging of the boost member 7A is suppressed in the stage prior to molding of the molded body, making it possible to more reliably mold a molded body of the desired shape.

[0066] Furthermore, the parison first comes into contact with the first mold 3b, thereby cooling the portion corresponding to the body of the molded body 9. This makes it easier for the parison to expand appropriately. Here, as described above, the swinging of the push-up member 7A is suppressed, so it is possible to prevent the parison introduced into the mold unit 3 from coming into contact with the push-up member 7A before it comes into contact with the first mold 3b. As a result, it is possible to prevent the portion corresponding to the mouth of the molded body 9 from being cooled, and it is possible to prevent the parison from not expanding appropriately.

[0067] 8, the extrusion head 4 is disposed above the mold unit 3 at position P1. The extrusion head 4 is configured to be able to feed the parison 8 into the mold unit 3 at position P1. The parison 8 is formed from molten resin and is preferably cylindrical, but may also be sheet-shaped.

[0068] 1-5. Cam track member 5 As explained in the first aspect, as shown in Figures 4 and 5, the cam shaft 3h moves along the cam track 5c of the cam track member 5, thereby opening and closing the dies 3b, 3c. As the cam shaft 3h moves, the distance D from the revolution axis C increases or decreases. The increase or decrease in the distance D corresponds to the elevation or lowering of the cam shaft 3h.

[0069] When the cylindrical portion 3h1 rises, the shaft portion 3h2 and rack gear 3f also rise. As the rack gear 3f rises, the pinion gear 3e and the second die 3c rotate clockwise. When the cylindrical portion 3h1 descends, the shaft portion 3h2 and rack gear 3f also descend. As the rack gear 3f descends, the pinion gear 3e and the second die 3c rotate counterclockwise. In this way, the gear mechanism formed by the rack gear 3f and pinion gear 3e converts the linear movement of the cam shaft 3h into rotational movement of the second die 3c, thereby opening and closing the second die 3c. Note that the gear mechanism may be another mechanism that can convert linear movement into rotational movement.

[0070] 1-6. Power Mechanism 10 and Shaft 11 The power mechanism 10 shown in Fig. 7 is composed of a motor and the like, and has the function of rotating the shaft 11. As shown in Fig. 7, one end of the shaft 11 is connected to the power mechanism 10, and the other end of the shaft 11 is connected to a bearing (not shown). The shaft 11 is connected to the base 2 and a base 12A of the switch mechanism 12 (described later), and rotation of the shaft 11 causes the base 2 and the base 12A to rotate.

[0071] 7 has a function of outputting timing information for supplying air to the air cylinder 7B1 to a control unit (not shown). Here, the control unit controls an air supply device (not shown) configured to be able to supply air to the air cylinder 7B1 via an air tube. In addition, the timing for supplying air to the air cylinder 7B1 corresponds to the timing for driving the engaging member 7C.

[0072] The switch mechanism 12 includes a base portion 12A, a switch portion 12B, and a plate-like member 12C. The base portion 12A is connected to the shaft 11. On the other hand, the shaft 11 is inserted into the plate-like member 12C, but the plate-like member 12C is configured not to rotate together with the shaft 11. The rotary molding machine 1 is provided with switch portions 12B in the number corresponding to the number of mold units 3, and in this embodiment, 15 switch portions 12B are provided.

[0073] Each switch portion 12B is provided with a switch 12B1 arranged opposite to the surface of the plate-like member 12C. A convex portion (not shown) is formed on the plate-like member 12C, and this convex portion is formed, for example, at a position corresponding to the timing for lifting the push-up portion 7A1. When the switch portion 12B passes the convex portion of the plate-like member 12C while rotating together with the base portion 12A, the switch 12B1 is pressed by the convex portion. This allows the control unit to obtain timing information for supplying air to the push-up mechanism 7 of the mold unit 3 corresponding to the pressed switch 12B1.

[0074] 1-7-2. Control of drive unit 7B by control unit In this embodiment, the control unit controls the drive unit 7B (air supply device) so that the push-up unit 7A1 rises (so that it can move from the first position to the second position) at the first timing. At the first timing, the second mold 3c is in a fully open state. The first timing is the timing when the mold unit 3 is located at position P41. Position P41 is a position between positions P4 and P1. Because the control unit controls the air supply device so that the push-up unit 7A1 rises at the first timing, interference between the molded product and the second mold 3c is suppressed, and the molded product is smoothly removed from the first mold 3b.

[0075] The control unit also controls the drive unit 7B (air supply device) to lower the push-up unit 7A1 (to move from the second position to the first position) at the second timing. The second mold 3c is fully open at the second timing, and the second timing is the timing after the molded product has been removed (pushed out) from the first mold 3b. The second timing is the timing when the mold unit 3 is located at position P42. The mold unit 3 is provided with a sensor (not shown) that detects whether the molded product has been removed from the first mold 3b and whether the push-up unit 7A1 is in a raised state. The control unit can obtain information related to the second timing from this sensor.

[0076] Then, the control unit controls the air supply device so that the push-up part 7A1 descends at the second timing, thereby avoiding interference between the next parison to be inserted and the push-up part 7A1, and allowing the parison to be smoothly re-injected onto the first mold 3b.

[0077] 2. Rotary Molding Method The rotary molding method according to the embodiment is carried out using a rotary molding machine 1. The rotary molding method according to the embodiment includes a parison injection step, a molding step, and a removal step.

[0078] In the parison injection process, the parison 8 extruded from the extrusion head 4 is injected between the first and second molds 3b, 3c while the second mold 3c is in an open state. The second mold 3c is in its most open state between positions P4 and P1, and then gradually closes as it moves from position P1 to P2, so that the parison 8 can be injected between the first and second molds 3b, 3c at a desired position between positions P42 and P2.

[0079] 2-2. Molding Step In the molding step, the parison 8 is molded using the first and second molds 3b, 3c. The shapes of the first and second cavity members 3b2, 3c2 when the second mold 3c is closed correspond to the outer shape of the molded body 9, so that the molded body 9 can be formed by molding using the first and second molds 3b, 3c. The molding may be blow molding or vacuum molding.

[0080] 2-3. Removal Process 2-3-1. Push-up Operation of Push-up Part 7A1: Push-up Part 7A1 Moves from First Position to Second Position In the removal process, the molded body 9 molded in the first mold 3b is removed from the first mold 3b. When the second mold 3c reaches position P41, the control unit controls the drive unit 7B (air supply device), and the engaging member 7C descends. This causes the first engaging portion 7C2 of the engaging member 7C to press down on the contact portion 7A3, and as a result, the push-up part 7A1 rises. This pushes up the molded body on the first mold 3b, and the molded body 9 is removed from the first mold 3b.

[0081] 2-3-2. Returning Operation of the Push-Up Unit 7A1: The push-up unit 7A1 moves from the second position to the first position. When the second mold 3c reaches position P42, the control unit controls the drive unit 7B (air supply device) to raise the engaging member 7C. This causes the second engaging portion 7C3 of the engaging member 7C to push up the contact portion 7A3, causing the push-up unit 7A1 to descend. This prevents interference between the next parison and the push-up unit 7A1.

[0082] 3. Other Embodiments The engaging member 7C and the contact portion 7A3 may be connected. The drive unit 7B may employ a system in which the boost member 7A is driven hydraulically, or a system in which the boost member 7A is driven by a motor. The boost member 7A may be provided in the second arrangement unit 3bs, and the air supply unit 6 may be provided in the first arrangement unit 3bt. The first and second molds 3b, 3c may be configured to open and close by rotating both the first and second molds 3b, 3c. The first and second molds 3b, 3c may be configured to open and close by moving closer and farther apart in parallel. The camshaft 3h may be configured to be directly connected to the molds.

[0083] 1: rotary molding machine, 2: base portion, 3: mold unit, 3a: support, 3b: first mold, 3b1: first accommodating portion, 3bt: first arrangement portion, 3bs: second arrangement portion, 3b11: groove portion, 3b12: shaft portion, 3b2: first cavity member, 3c: second mold, 3c1: second accommodating portion, 3c2: second cavity member, 3d: hinge portion, 3e: pinion gear, 3f: rack gear, 3ft: linear guide, 3g: support wall, 3g1: slit, 3h: cam shaft, 3h1: cylindrical portion, 3h2: shaft portion, 4: extrusion head, 5: cam track member, 5a : base plate, 5b: annular groove, 5b1: side surface, 5c: cam track, 6: air supply section, 7: push-up mechanism, 7A: push-up member, 7A1: push-up section, 7A2: bearing section, 7A3: contact section, 7B: drive section, 7B1: air cylinder, 7B2: piston, 7C: engagement member, 7C1: frame, 7C2: first engagement section, 7C3: second engagement section, 8: parison, 9: molded body, 10: power mechanism, 11: shaft, 12: switch mechanism, 12A: base section, 12B: switch section, 12B1: switch, 12C: plate-shaped member, 13: rail, C: revolution axis

Claims

DEPCT651. A rotary forming machine consisting of first and second dies and a cam shaft and cam orbital parts, in which the first and second dies and the cam shaft are assembled to rotate with their central axis of rotation. The cam orbital parts have cam orbits, and the cam shaft moves to follow the cam orbits during this rotation. The first and second dies open and close in accordance with the movement of the cam shaft. The angle between the said axis direction at the time the first and second dies are closed and the said axis direction at the time the first and second dies are opened shall not exceed 45 degrees when the longitudinal direction of the said cam shaft is defined as the axial direction.

2. A rotary forming machine specified in claim 1, in which the cam orbital parts are assembled to change their distance from the said central axis of rotation by moving in the circumferential direction. 3.

1. A rotary forming machine specified in Reputation 1 or Reputation 2, in which the cam orbital element is assembled by means of annular projections or annular grooves made on the base plate.

4. A rotary forming machine specified in Reputation 1 through Reputation 3, in which the first and second molds are connected by a hinge, and the first and second molds are opened and closed by relative rotation of the hinge at the center.

5. A rotary forming machine specified in Reputation 1 through Reputation 4, in which the first and second molds are opened and closed by means of the movement of the cam orbital element transmitted through a gear mechanism.

6. A rotary forming machine specified in Reputation 5, in which the gear mechanism is a mechanism that converts linear motion into rotational motion. 7.Any one of the rotary forming machines specified in Reputations 1 through 6, which is a rotary forming machine in which the axis of rotation makes an angle of no more than 45 degrees with respect to the horizontal plane.The rotary forming machine, consisting of a first and second die, and a pusher piece and a drive mechanism, is assembled to allow the second die to open and close relative to the first die. This pusher piece is manufactured at the first die and is assembled to move as needed from position one to position two. The workpiece on the first die is pushed up by this movement of the pusher piece from position one to position two. Position two is further away from the first die than position two. The drive mechanism has a clamping element and a drive mechanism. This clamping element is clamped to the pusher piece at positions one and two. This drive mechanism moves the clamping element, allowing the pusher piece to move from position one to position two.The rotary forming machine specified in claim 8 is a rotary forming machine in which the extruder has a contact and a axis brace, with the extruder made on one side of the extruder, the contact made on the other side of the extruder, and the axis brace made between the extruder and the contact, and the axis brace is provided to the first die, and the drive causes the extruder to move in a linear direction.

10. The rotary forming machine specified in claim 9 is a rotary forming machine in which the drive has an air cylinder and a piston, the piston is mounted on the air cylinder and connected to the extruder. 11.

11. A rotary forming machine specified in any of Reputations 8 through 10, which is also a rotary forming machine with an air supply section, which is fitted in such a way that it can supply air to the interior of the parison which forms the workpiece, which is positioned to face the air supply section, and which is fitted at the end of the air supply section to be bifurcated.