Parison forming machine

Abstract

A parison tube forming machine utilizes a radial compression heater to heat a very specific portion of a preform tube for stretching. The heater has a plurality of compression dies that form a central cavity for receiving the preform tube. The working surfaces of the compression dies are tucked onto the outer surface of the preform tube to heat the tube via conduction, which will heat the preform tube more accurately and more precisely. A first stretched portion of the preform tube is produced by stretching the preform tube after heating. Then, a second portion of the preform tube is located within the central cavity and is also heated by the radial compression heater and stretched to produce a second stretched portion of the preform tube and an unexpanded portion of the preform tube, or a balloon portion of the parison tube.

Description

Background of the Invention

[0001] Field of the Invention

[0002] The present invention relates to a parison forming machine and a method for forming a parison using the parison forming machine. Background Art

[0004] Medical balloons are used in a variety of medical procedures including, but not limited to, angioplasty, stent placement and expansion, stent graft placement and expansion, etc. A parison tube is a hollow plastic tube used as the raw material for forming medical balloons. The parison making machine is slower than expected and often produces a balloon portion with a tapered end that is longer than expected. A shorter tapered end may be desired as it provides better accuracy and definition of the expansion zone when forming the medical balloon. Summary of the invention

[0005] The present invention relates to a preform tube forming machine and a method of forming a preform tube using the preform tube forming machine. An exemplary preform tube forming machine utilizes a radial compression heater to heat a very specific portion of the length of a preform tube for stretching. The radial compression heater has a plurality of compression dies that form a central cavity for receiving the preform tube. The working surfaces of the compression dies are retracted onto the outer surface of the preform tube to heat the preform tube via conduction. This heating method heats the preform tube more accurately and more precisely, so that the necking of the preform tube during the stretching operation is well controlled. The first stretched portion of the preform tube is produced by stretching the preform tube after heating with the radial compression heater. Then, a second portion of the preform tube is positioned within the central cavity and is also heated by the radial compression heater. After heating the second portion, the preform tube is stretched to produce a second stretched portion of the preform tube and an unexpanded portion of the preform tube, or a balloon portion of the preform tube. The tapered end of the balloon portion may be sharper or shorter than the tapered end of a preform tube made by hot air heating because the heating zone is not as well controlled as it is in conduction heating. In addition, the compression die can be configured to remain in contact with the preform tube during the stretching operation, wherein the compression die is pushed inward by the die actuator and the compression die can contact the preform tube as the preform tube necks. Maintaining conduction heating during this stretching operation enables very controlled stretching, thereby reducing stress concentrations in the polymer. The preform tube has a balloon portion having a diameter greater than the diameter of the first stretch portion and the second stretch portion, such as 50% or more, 100% or more, 150% or more, 200% or more, and any range between and including the values ​​provided.

[0006] Exemplary preform tubes can be made of polymer materials that can be melted or softened by heating and stretched, such as plastics and particularly thermoplastics, including but not limited to polyethylene, polyester, polyamide, polyvinyl chloride, urethane, etc. The size of the diameter of the preform tube or balloon used for the preform can be designed to enter a tube in the body, such as a vascular system tube or a digestive system tube, and the diameter can be about 0.5 mm or more, 1 mm or more, 2 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, 40 mm or more, 50 mm or more, and any range between and including the listed diameters. The length of the balloon portion of the preform tube can be configured to expand and / or open a blood vessel (such as an artery or vein) in the body, or a portion of the digestive tract including the intestine. The length of the balloon portion may be approximately 2 mm or greater, 5 mm or greater, 10 mm or greater, 20 mm or greater, 40 mm or greater, 50 mm, 75 mm or greater, 100 mm or greater, and any range between and including the provided length values.

[0007] An exemplary parison forming machine may incorporate a first tube holder and a second tube holder for holding the end of the preformed tube. One or both of the tube holders may be moved during the stretching operation to move the two tube holders away from each other. The tube holder may be configured on a track and may be moved along the track by a tube holder actuator. For example, a motor may move the tube holder linearly along the track. The track may be any suitable guide for controlling the movement of the tube holder along the length axis of the preformed tube. An exemplary motor may be a stepper motor that has very precise control over the amount of movement and the speed of movement generated, or the stretching speed generated. In addition, the preform may be stretched at a constant or variable speed, and the stepper motor may achieve a programmable stretching rate to produce a uniformly stretched portion with a desired tapered end on the balloon portion.

[0008] An exemplary radial compression heater may employ a compression mold arranged around a central cavity, as described in any of U.S. Patent No. 9,956,604 to Blockwise Engineering LLC, U.S. Patent Publication No. 2020 / 0384523 to Blockwise Engineering LLC; the entire contents of each reference listed are incorporated herein by reference.

[0009] This summary of the invention is provided as a general introduction to some of the embodiments of the invention and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[0011] Figure 1 A perspective view of an exemplary preform tube for forming a parison tube having a balloon portion is shown.

[0012] Figure 2 A side view of an exemplary parison tube is shown with a balloon portion configured between a first stretch portion and a second stretch portion.

[0013] Figures 3 to 6 An exemplary parison forming machine for forming a parison tube is shown.

[0014] Figure 3 Shown is a preformed tube held between a first tube holder and a second tube holder and a radial compression heater disposed about the preformed tube.

[0015] Figure 4 Stretching of a preformed tube by two holders moving away from each other is shown, wherein a heated portion of the preformed tube is stretched to form a first stretched portion.

[0016] Figure 5 Moving the preform tube relative to the radial compression heater to position a new or second portion of the preform tube within the radial compression heater is shown.

[0017] Figure 6 This second portion of the preform tube is shown being stretched by two holders moving away from each other to form a parison tube configuring the balloon portion between the first and second stretch portions.

[0018] Figure 7 Shows Figure 6 An enlarged view of the present invention, in which a balloon portion 40 is constructed between the first stretched portion and the second stretched portion of the parison tube.

[0019] Figure 8 An exemplary radial compression heater is shown having a plurality of compression dies that move relative to each other to form a central cavity that converges onto a preform tube to heat the preform tube for stretching.

[0020] Fig. 9 A first end view of a radial compression heater configured about a preform tube to heat the preform tube is shown.

[0021] Fig.10 Shown after the preformed tube has been stretched Fig. 9A first end view of a radial compression heater is shown with the compression die moving radially inward with the necked tube to continue through the conduction heating tube during the stretching process.

[0022] Throughout the several views of the figure, corresponding reference numerals indicate corresponding parts. The accompanying drawings represent illustrations of some embodiments of the present invention and should not be considered to limit the scope of the present invention in any way. For ease of explanation, some drawings may not show all features and components of the present invention, but it should be understood that, where possible, features and components from one drawing may be included in other drawings. In addition, the drawings are not necessarily drawn to scale, and some features may be enlarged to show the details of specific components. Therefore, the specific structural details and functional details disclosed herein should not be interpreted as restrictive, but only as a representative basis for teaching those skilled in the art to adopt the present invention in various ways. DETAILED DESCRIPTION

[0023] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover non-exclusive inclusions. For example, a process, method, article, or apparatus that includes a series of elements is not necessarily limited to only those elements, but may include other elements that are not clearly listed or inherent to such process, method, article, or apparatus. In addition, the use of "a" or "an" is adopted to describe the elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be interpreted as including one or at least one, and the singular also includes the plural unless it is obvious that it is otherwise.

[0024] Certain exemplary embodiments of the present invention are described herein and shown in the accompanying drawings. The described embodiments are only for the purpose of illustrating the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art will recognize other embodiments of the present invention and certain modifications, combinations and improvements of the described embodiments, and all such alternative embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0025] Reference now Figure 1 and Figure 2 ,like Figure 2 The exemplary parison tube 30 shown consists of Figure 1 The preformed tube 20 is shown formed. The preformed tube 20 is stretched or necked to form a first stretched portion 32 and a second stretched portion 34 between which the balloon portion 40 is configured. Figure 1A perspective view of an exemplary preformed tube for forming a parison tube with a balloon portion is shown. The preformed tube has a wall 23 thickness from an outer surface 26 to an inner surface 28, a preformed tube diameter 29, and a length from a first end 22 to a second end 24. The shape of the exemplary preformed tube is cylindrical, i.e., a cylinder forming a conduit 21. The parison tube 30 has a balloon portion 40, the diameter 47 of which is greater than the diameter 37 of the first stretch portion and the second stretch portion. The balloon portion 40 has tapered ends 45, 45' that taper to the first stretch portion 32 and the second stretch portion 34, respectively. The balloon portion 40 has a length from the first end 42 of the balloon portion to the second end 44. The length 49 of the tapered end can be minimized by uniformly heating the preform with a radial compression heater. The balloon portion has an outer surface 46. The parison tube can be cut to a desired length from the first stretch-expanded end 33 to the second stretch-expanded end 35.

[0026] Reference now Figures 3 to 6 The exemplary parison forming machine 10 forms the parison tube 30 by selectively stretching the preform tube 20. Figure 3 As shown, the preformed tube 20 is held between a first tube holder 80 and a second tube holder 90. A radial compression heater 60 is disposed around the preformed tube 20 to heat a first portion of the preformed tube to achieve stretching. The radial compression heater has an actuator 63 that closes the compression die onto the outer surface of the preformed tube to heat the preformed tube by conduction, direct contact with the preformed tube. After effectively heating the tube, as shown in FIG. Figure 4 3. The preformed tube is stretched as shown to form the first stretched portion 32. The first tube holder 80 and the second tube holder 90 are moved away from each other on the first track 84 and the second track 94, respectively. It should be noted that the movement away may involve the movement of both tube holders, or only one moves while the other remains stationary. The first tube holder can be moved by a first tube holder actuator 82 that moves the first tube holder along the first track 84, such as a servo motor. Similarly, the second tube holder 90 can be moved by a second tube holder actuator 92 that moves the second tube holder along the second track 94, such as a servo motor. The servo motor can provide a very smooth movement and can enable the stretching rate to be customized to produce a uniformly stretched portion of the preformed tube.

[0027] like Figure 5As shown, the preform tube 20 moves relative to the radial compression heater to position a new or second portion of the preform tube within the radial compression heater 60. The controller 15 can control the movement of the components to position the second portion of the tube within the radial compression heater. The radial compression heater can be configured to move along the length axis 25 or the length of the preform tube, or the first tube holder and the second tube holder can be configured to move the preform tube so that the second portion of the preform tube is configured within the radial compression heater. The radial compression heater can be located on a track, which can be the same track as the first track or the second track. A single track can be used, such as a single track extending from a first track end 88 to a second track end 98. The mold actuator will gather around this second portion of the tube to apply heat again by conduction. The first tube holder 80 and the second tube holder 90 move away from each other to create a second stretched portion 34 and create a balloon portion 40 between the first stretched portion 32 and the second stretched portion 34 of the parison tube 30, as shown in FIG. Figure 6 Only one of the tube holders (ie, the second tube holder 90 ) is movable to move the first tube holder and the second tube holder away from each other to form the second stretched portion 34 .

[0028] like Figure 7 As shown, the balloon portion 40 is constructed between the first stretched portion 32 and the second stretched portion 34 of the preform tube 30. The preform tube is formed by repeatedly stretching and moving the preformed tube through the first tube holder 80 and the second tube holder 90 to configure the second portion of the tube in the radial compression heater 60 after the first portion has been stretched to form the first stretched portion 32.

[0029] like Figure 8 As shown, an exemplary radial compression heater 60 has a plurality of compression dies 62, 62' arranged about a central axis 56, the plurality of compression dies moving relative to each other to form a central cavity 65 having a working surface 64, the working surface folded onto the preformed tube to heat the preformed tube for stretching. The compression die or the central cavity 65 formed thereby has a first end 67 and a second end 69 and a length 68 for receiving the preformed tube. One or more heaters 61 can be configured to heat the compression dies.

[0030] like Fig. 9 As shown, an exemplary radial compression heater 60 is arranged around the preformed tube 20 to heat the preformed tube. The working surface 64 of the compression die 62 forms a central cavity 65 having a central cavity diameter 66, which contacts the outer surface 26 of the preformed tube. The preformed tube is heated by conduction and direct contact with the working surface 64.

[0031] like Fig.10As shown, an exemplary radial compression heater 60 is arranged around the first stretch portion 32 of the preformed tube 20 to continue to heat the preformed tube as the first stretch portion is stretched. The working surface 64 of the compression die 62 forms a central cavity 65 having a central cavity diameter 66, which contacts the outer surface 26 of the preformed tube. As shown, the compression die can be pushed inward by a die actuator to reduce the central cavity diameter and press the working surface into contact with the outer surface of the preformed tube as the preformed tube is stretched and reduced in diameter.

[0032] It will be apparent to those skilled in the art that various modifications, combinations and variations may be made to the present invention without departing from the scope of the present invention. The specific embodiments, features and elements described herein may be modified and / or combined in any suitable manner. Therefore, the present invention is intended to cover modifications, combinations and variations of the present invention, as long as the modifications, combinations and variations are within the scope of the appended claims and their equivalents.

Claims

1. A profile tube forming machine, comprising: a) a first tube holder; b) a second tube holder; c) a radial compression heater, the radial compression heater comprising: i) a plurality of compression molds, each compression mold having a working surface, wherein the plurality of compression dies are radially arranged relative to one another to form a central cavity defined by the working surface, wherein the central cavity has a central cavity diameter; ii) a heater configured to heat the compression mold; iii) a die actuator configured to move the plurality of compression dies inwardly to reduce the central cavity diameter; d) a preformed tube extending through the central lumen of the radial compression heater and having a length between the first tube holder and the second tube holder; wherein the radial compression heater is configured to heat a portion of the length of the preform tube between the first tube holder and the second tube holder; wherein the plurality of compression dies are configured to converge onto an outer surface of the preformed tube, wherein the working surfaces of the compression dies contact the preformed tube to heat the portion of the length of the preformed tube; and The first tube holder and the second tube holder are configured to move away from each other to stretch the preform tube and form a parison tube configuring a balloon portion between a first stretching portion and a second stretching portion.

2. The profile tube forming machine according to claim 1, further comprising: a track, and wherein the first tube holder is configured on the track; as well as A first tube holder actuator, wherein the first tube holder is actuated along the track by the first tube holder actuator.

3. The profile tube forming machine according to claim 1, further comprising: a track, and wherein the second tube holder is disposed on the track; as well as A second tube holder actuator, wherein the second tube holder is actuated along the track by the second tube holder actuator.

4. The profile tube forming machine of claim 1, wherein the preformed tube comprises a thermoplastic polymer.

5. The profile tube forming machine of claim 1, wherein the first tube holder and the second tube holder move in opposite directions to stretch the preformed tube to form the first stretched portion.

6. The profile tube forming machine of claim 1, wherein only one of the first tube holder and the second tube holder moves to stretch the preform tube to form the second stretched portion.

7. The profile tube forming machine of claim 1, wherein when the preform tube is stretched, the working surfaces of the plurality of dies are pushed radially inward by the die actuator to reduce the central cavity diameter.

8. The parison tube forming machine of claim 1 , wherein a second portion of the preform tube is configured to be positioned within the radial compression heater after producing the first stretched portion, and wherein the radial compression heater is configured to heat the second portion before the first tube holder and the second tube holder are configured to move away from each other to stretch the preform tube and produce the second stretched portion and the balloon portion of the parison tube.

9. The profile tube forming machine of claim 8, wherein the first tube retainer and the second tube retainer are configured to move the preform tube to position the second portion of the preform tube within the radial compression heater.

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