JP2005161576A - Preform holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preform holding device capable of stably holding a primarily molded preform by a simple mechanism without causing deformation and capable of contributing to the compactification and weight reduction of an apparatus. <P>SOLUTION: This preform holding device is constituted of a cylindrical case (2), a holding member (3) formed by combining a plurality of vertically divided dividing pawl pieces (3a) and (3b) in an expansible manner and inserted in and held to the cylindrical case (2) at its leading end part and a means (4) for operating the dividing pawl pieces (3a) and (3b) so as to expand them. The respective dividing pawl pieces (3a) and (3b) are brought into contact with the inner periphery of the mouth part of the preform by expansion force caused in a state that the protruded part (30) of the holding member (3) is inserted in the mouth part (P1) of the preform (P) to hold the preform from the inside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a preform receiving apparatus for preforming a preform formed in the manufacture of a plastic bottle or a holding apparatus for a preform used for transfer for transport to a subsequent process.

  A bottle made of a polyester resin such as polyethylene terephthalate (PET) (so-called PET bottle) is obtained by first forming a preform as an intermediate and then biaxially stretching it by a blow molding method or the like. In the production of this PET bottle, as shown in FIGS. 14 and 15, the preform P primarily molded by the molding machine 100 is taken out from the molding machine 100 by the take-out device 102 and held in the receiving device 110. It is held and received by the device 111, transferred to a transfer device 104 such as a conveyor, and transferred to a subsequent step, for example, a step of crystallizing the mouth portion or a secondary forming step of obtaining a final product.

  The molding of the preform by the molding machine 100 is usually performed in large numbers, and a large number of preforms P taken out by the take-out device 102 are arranged side by side. Therefore, the holding device 111 is provided so that the receiving device 110 can hold and receive the multiple preforms P at the same time. For example, as shown in the figure, a moving table 112 that can move between the receiving position and the delivery position to the transfer device 104 is provided, and a plurality of substrates that are arranged in parallel vertically and horizontally on a support substrate 113 provided on the moving table 112. The holding device 111 is arranged so that the preforms can be held simultaneously for each row. In the case of a system in which the preform P is received sideways as shown in the figure, the preform P is brought into an upright state by the rotation of the support substrate 113 and transferred to the transfer device 104.

  Conventionally, in the receiving device 110 or the like, as a holding device for holding a large number of preforms P arranged in parallel in the vertical and horizontal directions, a method of chucking and engaging the outer periphery of the mouth of the preform (for example, the following patent document) 1) Or a method of holding a preform by a suction means (for example, Patent Document 2 below) is adopted.

  In the case of the chuck system, a chuck device that chucks the preforms in parallel for each of the vertical and horizontal rows is arranged side by side, but the chuck device itself becomes large in order to chuck the preform from the outside, and the chuck A cylinder device for supporting and operating the device is also required, and the entire device becomes heavy and the operation speed is slow. As a result, if the mouth portion of the preform is strongly clamped from both sides, the preform that is completely cooled and not cured may be deformed.

  Therefore, recently, as shown in FIGS. 14 to 16, the suction nozzle 117 is provided on the front surface of the support substrate 113 in accordance with the position of each preform, while the suction nozzle 117 in the vertical and horizontal directions is formed on the back surface of the support substrate 113. A communication chamber 118 communicating with the suction nozzle 117 is provided for each row, and a suction device (not shown) is connected to the communication chamber 118, and the mouth P1 of the preform P taken out by the take-out device 102 is connected to the mouth P1. A method of sucking by inserting the suction nozzle 117 is increasing.

However, in the case of this suction method, if the suction force becomes too strong, the preform P that has not been completely cooled and hardened may be deformed, such as being dented by the suction force. On the other hand, if the suction force by the suction nozzle is weakened, the preform becomes unstable and the preform may fall off during the transfer. In some cases, the preform cannot be sucked and held. If the preform cannot be held by one suction nozzle or falls off, the suction force by the other suction nozzles becomes weak and the holding state becomes more unstable.
JP 2002-361720 A JP 2001-105480 A

  The present invention has been made in view of the above, and in manufacturing a plastic bottle, a receiving device for receiving a preform formed by primary molding and transferring it to a transporting device or the like to the next process, or another transporting device is provided. As a holding device for the preform used in the transfer device to the transport device, it is a simple mechanism, but it can hold the preform reliably and without risk of deformation, making the equipment compact and lightweight. It is intended to provide a holding device that can contribute and reduce the installation space, and further provides a holding device having a structure that can hold the rubbing portion of the member that holds the preform from the inside without making it inside the preform. It is something to try.

  The present invention is a preform holding apparatus that solves the above-described problems, and includes a cylindrical case that is attached and fixed to a support substrate, and a plurality of divided claw pieces that are vertically formed. A holding member that is fitted into the cylindrical case so that the distal end portion is projecting in a state where the split claw pieces are assembled so as to be expandable, and is held in an detachable manner, and the holding member The holding member is capable of inserting a protruding portion from the cylindrical case into the mouth of the preform and expanding in the inserted state. Each of the divided claw pieces is provided so as to be in contact with the inner periphery of the mouth of the preform by the action to hold the preform.

  According to this preform holding device, in the state in which the holding member is inserted into the mouth portion of the preform, each divided claw piece is expanded so that the divided claw piece strongly contacts the inner periphery of the mouth portion of the preform. In this way, the preform can be reliably and stably held without fear of being pulled out from the inside. Moreover, since each of the divided claw pieces of the holding member comes into contact with the inner periphery of the mouth portion of the preform with a substantially uniform force, even if the preform is completely cooled and not hardened, deformation such as a dent is caused. There is no risk.

  In the preform holding device, the holding member has a tapered portion with a tapered tip at a protruding portion from the cylindrical case, and an outer surface of each divided claw piece on the base side of the protruding portion is widened. It is formed as an abutting surface portion that abuts against the inner peripheral surface of the mouth portion of the preform during operation, and can be expanded to a position where the outer diameter of the corresponding contacting surface portion is slightly larger than the inner diameter of the mouth portion of the preform. preferable.

  Accordingly, the holding member can be easily inserted into the inner periphery of the mouth portion of the preform, and the contact surface portion of the outer surface thereof is strengthened to the inner periphery of the mouth portion of the preform by the expanding action of each divided claw piece of the holding member. In addition, the preform can be held in a stable manner, so that the preform can be stably held, and even if the preform is rotated sideways or downward during transfer, there is no risk of removal.

  In the preform holding device, an engagement protrusion that is provided with an inner flange-like locking portion on the inner periphery of the distal end portion of the cylindrical case and that engages the locking portion on the outer surface of each divided claw piece of the holding member. The holding member is held in a non-removable manner by the engagement of the engaging convex portion and the locking portion, and is provided so as to be expandable with the locking portion as a fulcrum. Those are preferred. That is, by being configured in this manner, each of the divided claw pieces of the holding member formed in a vertically divided manner can be expanded without being rubbed at a portion such as a divided surface.

  Each of the divided claw pieces of the holding member has a dividing surface in a rear end side portion cut away from the engagement convex portion in a tapered shape, and the rear end side portion can be reduced in diameter within the range of the cutout, It is preferable that the projecting portion from the cylindrical case is provided so as to be able to expand by reducing the diameter of the rear end side portion. Thereby, each division claw piece of the above-mentioned holding member can expand the tip side part projected from the cylindrical case reliably by pressing the rear end side part from the outside and reducing the diameter, As described above, the inner periphery of the mouth of the preform can be reliably inscribed.

  Further, a spring means is provided in the cylindrical case for elastically pressing the engaging convex portion of each divided claw piece of the holding member toward the locking portion. The divided claw pieces are held in a closed state, and means for expanding the holding member is provided to expand the divided claw pieces against the elastic pressing force of the spring means. Things are good. Thereby, each divided claw piece of the holding member can be expanded at the time of the action by the spreading operation means, and each divided claw piece of the holding member is closed except at the time of the action by the spreading action means. It can be kept in a state and can be inserted and removed from the preform without difficulty.

  Further, as the means for expanding the holding member, a pushing member supported by the advance / retreat means in the axial direction of the holding member so as to be able to advance and displace in the cylindrical case. It is assumed that there is provided a pushing member having a taper hole that is circumferentially fitted to the outer periphery of the rear end of the holding member and can reduce the diameter of the rear end portion of each of the divided claw pieces by advancing displacement. Thereby, each split claw piece can be surely expanded by a slight advance displacement of the pushing member by the advancing / retreating means, so that a large stroke is not required as the advancing / retreating means, and a small size can be achieved. An air cylinder, an electromagnetic solenoid, or the like can be easily used.

  That is, when the advancing / retracting means is made of an air cylinder that moves the pushing member back and forth, it may be smaller than a conventional cylinder device that operates a chuck device that chucks from the outside, and the holding member is Combined with the small parts that can be inserted into the mouth of the preform, the holding device can be made compact.

  According to the preform holding device of the present invention, unlike the conventional chuck method and suction method from the outside, the preform is held from the inside by the expanding action of the holding member that can be inserted into the mouth of the preform. Preforms can be held reliably and stably without fear of being pulled out, and even preforms that are completely cooled and not cured can be held without causing deformation.

  In particular, each of the divided claw pieces of the holding member is provided in such a manner that it can be expanded with the engaging portion of the engaging convex portion of the outer surface and the engaging portion of the inner periphery of the tip end portion of the cylindrical case as a fulcrum. There will be no rubbing part for the spreading action at the contact part of each divided claw piece of the holding member inserted in the inside, appearance is good, and there is a concern about fine powder intrusion due to rubbing by the user There is also no risk of causing.

  Furthermore, according to the preform holding device of the present invention, the entire device including the holding member and the means for performing the expansion operation can be configured in a compact manner, which can contribute to simplification and weight reduction of the device.

  For example, in the case of use in a receiving device from a take-out device of a molding machine, the structure of the receiving device can be used even when a large number of the preforms taken out from the molding machine are used in parallel in the vertical and horizontal directions. It can be simplified as compared with the conventional device, and the weight and space can be reduced.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of a preform holding device according to the present invention, FIG. 2 is a front view from the front end side of a split-type holding member of the device, and FIG. FIG. 4 is a front view from the front end side of the expanded holding member, and FIG. 5 is a partial enlarged schematic sectional view for explaining the expanded state of the split holding member. FIGS. 6 to 9 and FIGS. 10 to 13 show a second embodiment and a third embodiment, respectively, in which the holding member is divided differently.

  In this first embodiment, the holding device A according to the present invention is mounted on a support substrate 1 and basically has a cylindrical case 2 and a split-type holding member 3 that can be expanded as will be described later. And means 4 for expanding the holding member 3.

  The cylindrical case 2 is fixed to one surface of the support substrate 1 by screw fastening means 11 such as bolts. An inner flange-like locking portion 13 is provided on the inner periphery of the distal end portion of the cylindrical case 2 so that the holding member 3 can be engaged in a non-detachable manner as will be described later.

  The split-type holding member 3 is composed of a plurality of split claw pieces that are vertically divided into a plurality in the circumferential direction. As in the second and third embodiments to be described later, it can be vertically divided into three, four, or more, but in the first embodiment of FIGS. It is vertically formed on the two divided claw pieces 3a and 3b, and the cylindrical shape is formed so that the tip side portion has a protruding shape in a state where the divided claw pieces 3a and 3b are assembled so as to be expandable. The case 2 is engaged and held so that it cannot be removed.

  As the engaging and holding means of the holding member 3 by the cylindrical case 2, engaging convex portions 33 are provided on the outer surfaces of the divided claw pieces 3 a and 3 b of the holding member 3, respectively. By engaging with the engaging portion 23 of the inner peripheral portion of the distal end of the cylindrical case 2, the divided claw pieces 3a and 3b are held so as not to be removable. Further, each of the divided claw pieces 3a and 3b of the holding member 3 has the locking portion 23 engaged with the engaging convex portion 33 as a fulcrum, and the protruding portion 30 from the cylindrical case 2 expands toward the tip side. It is provided so that it can.

  The projecting portion 30 of the holding member 3 from the cylindrical case 2 can be inserted into the mouth portion P1 of the preform P which has been primarily molded and taken out, and by the expanding action in this inserted state. Each of the divided claw pieces 3a and 3b is provided so as to abut (inscribe) the inner peripheral surface of the mouth portion P1 of the preform P so as to press outward and hold the preform P. ing.

  For this reason, the holding member 3 has a tip end portion 31 of the projecting portion 30 that is tapered, and the outer surface of each of the divided claw pieces 3a and 3b on the base side of the projecting portion 30 is a preform during the expansion operation. The contact surface portion 32 of the P mouth portion P1 with respect to the inner peripheral surface is formed in a tapered shape smaller than the tip portion, and is formed to be slightly larger than the inner diameter of the mouth portion of the preform P, particularly at the maximum expansion. Has been.

  The abutment surface portion 32 of the holding member 3 is substantially parallel to the inner peripheral surface of the mouth portion of the preform P when expanded in a state of being inserted into the mouth portion P1 of the preform P. The taper angle β and the like in the closed state are set so that substantially the entire length direction of the contact surface portion 32 can contact the inner peripheral surface of the mouth portion substantially evenly. Reference numeral 34 denotes a recess between the abutment surface portion 32 and the engagement convex portion 33, and the inner flange-like locking portion 23 of the cylindrical case 2 is located in the recess 34, and the expanding action is performed. A slight displacement in the axial direction of each of the divided claw pieces 3a and 3b can be allowed.

  The divided claw pieces 3a and 3b of the holding member 3 are notched so that each divided surface in the rear end side portion 35 of the cylindrical case 2 is tapered as shown in the figure. The rear end side portion 35 can be reduced in diameter within the range of the notch 36, and the protruding portion 30 from the cylindrical case 2 is provided to be expandable by the reduced diameter of the rear end side portion 35. . Therefore, the opening angle α of the notch 36 is set to be slightly larger than the taper angle β of the contact surface portion 32 of each divided claw piece 3a, 3b. The rear end portion 35 is rounded by a rounded curved surface from the outer peripheral surface to the rear end surface.

  And in the said cylindrical case 2, along the inner periphery, between the engagement convex part 33 of each division claw piece 3a, 3b of the said holding member 3, and the said support substrate 1, the said engagement convex part A spring means 41 such as a coil spring that elastically presses 33 toward the locking portion 23 is interposed.

  That is, by the pressing force of the spring means 41, the engaging projection 33 is held in contact with the locking portion 23 as shown by the solid line in FIG. , 3b are held closed, and the expanding means 4 described later acts on the rear end side portion 35 of each of the divided claw pieces 3a, 3b, thereby reducing the pressing force by the spring means 41. On the other hand, the engaging convex portion 33 is displaced with respect to the locking portion 23 as shown by a chain line in FIG. 5 so that the distal end sides of the divided claw pieces 3a and 3b are expanded.

  A synthetic resin collar member 42 is interposed between the spring means 41 and the engaging convex portion 33 of the holding member 3, and the elastic pressing force of the spring means 41 is applied to each engaging convex portion 33. It is comprised so that it can give equally.

  As the means 4 for expanding the divided claw pieces 3a, 3b of the holding member 3, the divided claw pieces 3a, 3b can be expanded against the spring means 41 as described above. Any structure can be used, but in the case of the embodiment shown in the drawing, advancement / retraction means 45 appropriately advances and displaces in the axial direction of the holding member 3 in the cylindrical case 2. The pressing member 43 is supported so as to be capable of being circumferentially fitted to the outer periphery of the rear end of the holding member 3 and reducing the rear end side portion 35 of each of the divided claw pieces 2a and 2b by advancing displacement. A pressing member 43 having a tapered hole 44 that can be made is provided.

  Specifically, the advancing / retreating means 45 is provided on the other surface side of the support substrate 1, that is, on the side opposite to the mounting side of the cylindrical case 2, and the advance / retreat means 45 of the support substrate 1 is passed through the through holes 12. A rear end portion of the pushing operation member 43 is connected to the output shaft 45a, and the pushing operation member 43 is provided to advance and retreat.

  As shown in FIG. 1, the pushing member 43 is usually held in a state where the tapered hole 44 is in contact with the outer periphery of the rear end of the holding member 3 or has a slight gap. When holding, the output shaft 45a of the advance / retreat means 45 is advanced so that the end portion of the holding member 3 can be pressed in the diameter-reducing direction by the tapered hole 44. Each divided claw piece 3a, 3b is configured to be able to expand.

  As the advancing / retracting means 45, various advancing / retreating means capable of advancing / retreating the pushing operation member, such as using an electromagnetic solenoid or a cam mechanism to advance / retreat the pushing operation member, can be used. However, in practice, it is particularly preferable to use a small air cylinder as shown in the figure because it can be made compact and there are few malfunctions.

  6 to 9 show a second embodiment in which the holding member 3 is composed of three divided claw pieces 3a and 3b divided into approximately three equal parts in the circumferential direction, and FIGS. A third embodiment in which the holding member 3 is composed of four divided claw pieces 3a, 3b, 3c, 3d is shown. Also in these embodiments, the other configuration aspects except the holding member 3 are configured in the same manner as in the case of the first embodiment described above and are held so as to be expandable. The same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, in either case of the holding member 3 composed of the three divided claw pieces 3a and 3b or the holding member 3 composed of the four divided claw pieces 3a, 3b, 3c and 3d, as shown in the figure, Projecting portion 30, tip portion 31, abutting surface portion 32, engaging convex portion 33, concave portion 34, rear end side portion 35, notch 36 and engagement case structure of cylindrical case 2, and expansion possible The configuration and means for achieving the above, the means for expanding the same, the combination mode, and the like can be configured and implemented in the same manner as described in the first embodiment.

  Although it is possible to carry out with the number of the divided claw pieces of the holding member 3 being five or more, from the point of view of the number of parts, the ease of assembly, the stability of the holding state of the preform, etc. 4 is particularly preferred.

  In any case, the holding device A of each of the above-described embodiments is used by attaching a necessary number to the support substrate 1 in the transfer operation in the manufacture of the preform P. For example, when used as a receiving device from a molding machine take-out device, a required number of holding devices A are arranged in parallel in the vertical and horizontal directions according to the molding arrangement in the molding machine, that is, the arrangement of the take-out devices. When the preform P is received from the take-out device, the protruding portion 30 of the holding member 3 protruding from the cylindrical case 2 of the holding device A is opposed to the preform P at the take-out position by the take-out device. Then, the preform P is inserted to a position where the opening end of the preform P is in contact with or close to the front end surface of the cylindrical case 2.

  In this state, the advancing / retreating means 45 in the means 4 for performing the expanding operation is operated to displace the pushing operation member 43 supported by the output shaft 45a. Due to the advancing displacement of the pressing member 43, the rear end side portion 35 of the holding member 3 is pressed against the spring means 41 by the tapered hole 44 that is in circumferential contact with the outer periphery of the rear end to reduce the diameter. As a result, each of the divided claw pieces 3 a, 3 b or 3 a, 3 b, 3 c or 3 a, 3 b, 3 c, 3 d of the holding member 3 is engaged with the engaging convex portion 33 on the outer surface to the engaging portion 23 of the cylindrical case 2. In the joined state, the front end side portion is expanded, and the contact surface portion 32 comes into strong engagement with the inner peripheral surface of the mouth portion of the preform p, so that the preform P is removed from the inside. It can be reliably and stably held without fear. Moreover, since the holding member 3 comes into contact with the mouth part P1 of the preform P from the inside to the outside, the preform P is easily deformed even if the preform P is completely cooled and not hardened. There is no fear. Therefore, the holding can be performed with a stronger force than when chucking from the outside, and the holding state is further stabilized.

  In particular, each of the plurality of divided claw pieces 3a, 3b or 3a, 3b, 3c or 3a, 3b, 3c, 3d of the holding member 3 has a locking portion 23 of the cylindrical case 2 as shown by a chain line in FIG. The contact portion between the divided surfaces serving as a fulcrum, particularly in the case of three or more divided shapes, the central portion that is the intersection of the divided surfaces is slightly displaced forward, and the proximal end portion of the notch 36 in the rear end side portion 35 As the contact position on the surface is changed, it is rotated outward and spreads, so that there is no friction at the joint between the divided surfaces, and there is a risk that the user may be concerned about fine powder intrusion due to friction. Nor.

  Then, when the advancement / retraction means 45 releases the advancement of the pushing member 43 and retracts it to the original position, the divided claw pieces 3a, 3b or 3a, 3b, 3c or 3a, 3b, 3c, 3d It becomes a closed state by the urging force of the spring means 41 that presses the engaging convex portion 33 and can be extracted from the preform P without difficulty.

  The preform holding device of the present invention is a receiving device for receiving a preform taken from a molding machine for primary molding and transferring it to a transport device for subsequent processing in the production of a plastic bottle. It can be suitably used for handling the transfer of various preforms such as a transfer device for transfer from the transfer means to another transfer means.

It is sectional drawing which shows the 1st Example of the holding device of the preform concerning this invention. It is a front view from the front end side of the division | segmentation type holding member of an apparatus same as the above. It is sectional drawing of the state holding the preform by the apparatus same as the above. It is a front view from the front end side of the holding member expanded same as the above. It is a partial expanded schematic sectional drawing explaining the expansion state of a division | segmentation type | mold holding member. It is sectional drawing which shows the 2nd Example of the holding | maintenance apparatus of this invention. It is a front view from the front end side of the division | segmentation type holding member of an apparatus same as the above. It is sectional drawing of the state holding the preform by the apparatus same as the above. It is a front view from the front end side of the holding member expanded same as the above. It is sectional drawing which shows the 3rd Example of the holding | maintenance apparatus of this invention. It is a front view from the front end side of the division | segmentation type holding member of an apparatus same as the above. It is sectional drawing of the state holding the preform by the apparatus same as the above. It is a front view from the front end side of the holding member expanded same as the above. It is a schematic plan view showing an example in which a conventional suction type holding device is used in a receiving device for a preform taken out from a molding machine. It is a simplified front view of a receiving apparatus same as the above. It is sectional drawing of a suction-type holding | maintenance apparatus.

Explanation of symbols

A: Holding device P: Preform P1: Mouth part 1: Support substrate 11: Screw fastening means 12: Through hole 2: Cylindrical case 23: Locking part 3: Holding members 3a, 3b, 3c, 3d: Dividing claw pieces 30: Projection part 31: Engagement convex part 32: Contact surface part 33: Engagement convex part 34: Concave part 35: Rear end side part 36: Notch 4: Expanding operation means 41: Spring means 42: Color member 43: Push Operation member 44: Tapered hole 45: Advance / retreat means 45a: Output shaft α: Opening angle of notch β: Opening angle of protruding portion

Claims (7)

A cylindrical case attached and fixed to the support substrate;
It consists of a plurality of split claw pieces that are vertically split, and each split claw piece is assembled so that it can be expanded. A retaining member engaged and held impossible;
A means for expanding each split claw piece of the holding member,
In the holding member, the protruding portion from the cylindrical case can be inserted into the mouth portion of the preform, and each split claw piece abuts on the inner periphery of the mouth portion of the preform by the expanding action in the inserted state. A preform holding device, wherein the preform holding device is provided to hold the preform.   The holding member has a tapered end at the protruding portion from the cylindrical case, and the outer surface of each divided claw piece on the base side of the protruding portion is the inner periphery of the mouth of the preform when the expanding operation is performed. The preform holding according to claim 1, wherein the preform is formed as an abutting surface portion that abuts against the surface, and can be expanded to a position where the outer diameter of the corresponding surface portion is slightly larger than the inner diameter of the mouth of the preform. apparatus.   An inner flange-like locking portion is provided on the inner periphery of the distal end portion of the cylindrical case, and an engagement convex portion that engages with the locking portion is provided on the outer surface of each divided claw piece of the holding member, 3. The holding member according to claim 1, wherein the holding member is held in a non-removable manner by the engagement of the engagement convex portion and the locking portion, and is provided so as to be expandable with the locking portion as a fulcrum. Preform holding device.   Each of the divided claw pieces of the holding member has a dividing surface in a rear end side portion cut away from the engagement convex portion in a tapered shape, and the rear end side portion can be reduced in diameter within the range of the cutout, The preform holding device according to claim 3, wherein a projecting portion from the cylindrical case is provided so as to be expanded by a reduced diameter of a rear end side portion.   A spring means is provided in the cylindrical case for elastically pressing the engaging convex portion of each divided claw piece of the holding member toward the locking portion. Normally, the divided claw is moved by the spring means. A means for expanding the holding member is provided so as to expand each of the divided claw pieces against an elastic pressing force by the spring means while the piece is held in a closed state. The preform holding device according to 3 or 4.   As the means for expanding the holding member, a pushing member supported by the advance / retreat means in the axial direction of the holding member so as to be able to advance and displace in the cylindrical case. 6. The preform according to claim 5, further comprising a pressing member having a tapered hole that is circumferentially fitted to the outer periphery of the rear end and has a taper hole capable of reducing the diameter of the rear end side portion of each divided claw piece by advancing displacement. Holding device.   The preform holding device according to claim 6, wherein the advance / retreat means is configured to advance / retreat the pushing member by an air cylinder.

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