JPH0332449B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates generally to containers, and more particularly to an apparatus for making thermoplastic headpieces for plastic or laminate tubes with fully molded sealing surfaces and concentric orifices. Techniques for manufacturing thermoplastic headpieces for plastic tubes and laminate tubes are well known and are described, for example, in U.S. Pat. No. 2,624,071;
There are No. 3260410 and No. 3207833. Injection molding method (injection molding method)
is a traditionally used manufacturing method, and its typical feature is that the molten thermoplastic material is injected through an injection cylinder into a molding device that conforms to the shape of the headpiece to be molded. It has a hollow part that contains a part that The top surface of the cavity, referred to as the cavity sealing surface, has an opening through which the thermoplastic material is conveyed into the mold cavity. The molding apparatus also has a housing or cover that closes the top of the cavity and a passage extending through the cover.
Note that the passage communicates with the opening in the sealing surface. To form the headpiece, an injection machine is coupled to a mold machine, and the thermoplastic material is
From the outlet of the cylinder, it is conveyed through a passage in the cover, through an opening in the sealing surface, and into the molding cavity. More and more thermoplastic material is injected until the mold cavity is filled. After the molten thermoplastic material has solidified, the headpiece is removed and finished. Traditionally, this injection/coagulation process produces thermoplastic foreign material (referred to as flash) that extends from the sealing surface of the headpiece and must be removed during finishing. This flash is due to material hardening within the passageway and remaining adhered to the sealing surface when the cover is removed. The hardened headpiece is then positioned for finishing operations, and an automatic snipping or trimming device cuts the flattening of the headpiece above the sealing surface with thermoplastic protrusions extending from the sealing surface. . This protrusion often reaches a length of 0.76 mm (0.03 inch) depending on manufacturing tolerances. As a result, undercutting or quality snipping of the recessed portion of the cap is also required to provide clearance between the underside of the cap and the protrusion. Although this undercut is standard practice for plastic caps used in commercial plastic tubes for the pharmaceutical market, this undercut or high-quality snippet is commonly used in applications where metal caps and plastic tubes have traditionally been used. No work is added to the cap. Smooth finishing of the metal tube sealing surface with a lathe type tool typically does not require cutting within the cap. Switching from plastic to metal caps for flexible tube caps typically requires costly and time-consuming mold changes of the metal caps to accommodate thermoplastic extrusions. In addition, the traditional tooling currently used in this manufacturing method is to create the cavity and orifice of the headpiece using a molding device configured to place a male part within a female part. It's on. The male part is characterized by rocking during the injection cycle so that the orifice is no longer concentric with the neck of the headpiece. Some metal cap products have an inner dome, in which case an orifice concentric with the neck and a smooth finished sealing surface are necessary for the cap to properly seal over the headpiece. There is a commercial need for a plastic or laminate headpiece that can completely seal the underside of a metal capped product and also has a concentric orifice. In addition, a headpiece is desired that reduces tube manufacturing costs by eliminating the need for snipping or trimming and by providing a fully molded, smooth finished orifice concentric with the sealing surface of the headpiece. If these needs are met,
It would be possible to compete on price between plastic tubes with smooth sealing surfaces and laminate tubes with headpieces and the metal tubes currently on the market. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a plastic headpiece that does not require undercuts or high-quality snipping in the cap recess, and thus to provide an apparatus for manufacturing a headpiece that can completely seal the underside of a metal cap article. The next object is to provide a manufacturing apparatus for a headpiece having a concentric orifice and a sealing surface that can be finished smoothly using a complete molding method, thereby eliminating the need for snipping foreign matter on the sealing surface necessary for product finishing. Other objects of the invention will become more fully understood from the following description, which, taken in conjunction with the accompanying drawings, discloses preferred embodiments of the invention. The present invention includes an apparatus for manufacturing the headpiece of a plastic tube or laminate tube body. Using conventional injection molding equipment in combination with molding equipment designed for plastic or laminate tube production, the method uses internal recessed runners or external runner systems to perform mold operations and headpieces. Work to glue it to the tube sleeve. Apparatus for forming thermoplastic headpieces used for fusion bonding with tubular bodies includes a male part and a female part, the latter of which is in contact with the former so as to at least partially define a cavity defining the shape of the headpiece. It has a mechanism to accept it inside. The headpiece has an inner wall and an outer wall joined by a sealing surface, but the sealing surface is
A side wall having at least one opening and at least one of an inner wall and an outer wall. The female part has a runner that receives thermoplastic material. The male and female parts cooperate to define and define at least one passageway. The passage communicates at one end with an opening through which the thermoplastic material entering from the runner is conveyed into the cavity, through which the headpiece is completely molded. A sealed surface can be obtained. The cavity passes through either the inner wall or the outer wall,
Filled with thermoplastic material, this molten material will then solidify. After solidification, the headpiece is removed from the cavity and the upper or sealing surface of the neck is completely molded and has a smooth finish. The reason for the smooth finish is that thermoplastic heterogeneous solidification, commonly called flash, forms on the sidewalls. After solidifying in the runners and passageways, this flash, which remains attached to the side walls, is removed during the sprue removal process. The tube body or sleeve is
It is placed in the lower part of the cylinder in the mold cavity and is fused with the thermoplastic material of the headpiece during the injection operation. The tube is then capped and packaged for shipping. An example of the present invention will be explained with reference to FIGS. 1 to 6, which show an inner recessed runner system. In the same drawing, an injection molding apparatus is generally designated by the numeral 10 and includes a conventional injection molding apparatus 12 and a molding apparatus 14. The apparatus includes, in accordance with the present invention, a plurality of injection devices for simultaneously filling a plurality of different mold devices, which devices are coordinated with a single indexing device. The injection device is also capable of filling multiple mold devices simultaneously through a single injection course. This injection device 12 includes:
There is an injection cylinder 16 that defines a chamber 18 within which a thermoplastic material 20 (typically in the form of pellets) is placed and melted by a heating device (not shown). Reciprocating piston 22 within chamber 18
The material 20 is squeezed and the discharge port (orifice) 2 is
It can be extruded through 4. The injection device 12 includes an injection head 26 that may be integral or attached to the device. Channel 28 extends axially through injection head 26 and communicates with chamber 18 with an inlet at outlet 24. The injection unit 12 can be equipped with a device (not shown) for moving the device 12 toward the molding device 14 and connecting it to, or axially disconnecting it from, the molding device 14. Alternatively or additionally, the molding device 14
A device can be coupled to the molding device 14 for moving toward and away from the injection device 12 . Mold apparatus 14 includes a female part 32 and a male part 58. The female part, also referred to as a die, includes a die housing 34, an annular collar 36, and separate neck plates 38, 40 which are connected to a cam of the lower sleeve 42 which acts against the collar 44. When the actuator moves to the closed position, the outer circumferential surface of the neck mold part N and the threaded part 46 are formed. Die housing 34
has a central opening 48 in its upper end surface and engages an insert 50;
It's on top of 40. The insert 50 also has a runner 52 which is connected to the channel 28.
It communicates with chamber 18 through. The upper end of the insert 50 is properly flanged at 53 to sit securely against the upper wall (face) 54 of the die housing 34 and is recessed to receive the tip of the injection head 26. (not shown) can be attached. The male part or mandrel 58 serves as the inner core of the molding device 14, while the shoulder molding part, or Poinçon 60, on which the sleeve of the tube body is cast, and the neck inner molding part, or Soupape. 62 included. Furthermore, regarding the mandrel 58, its installation,
Details regarding casting the tube body sleeve B and properly positioning the mandrel 58 in the mold position within the die 32 are provided in U.S. Pat.
It is disclosed in the specification of No. 3207833. The sawpup 62 is positioned in the middle of the upper end of the shoulder molded part 60 and can be slid into a central hole 66 passing through the male part 58. The inner surface of the female part 32 corresponds sufficiently to the outer surface of the male part 58, and together define the shape of the mold cavity 76 which corresponds to the shape of the tube. The cavity 76 thus includes an upper portion corresponding to the headpiece shape and a lower cylindrical portion into which the preformed tube body sleeve B is received. The upper portion 63 of the sawpup 62, together with the neck plate 38 and insert 50, is specially shaped to form a molded neck N. As best seen in FIGS. 5 and 6, the top surface 68 of the sawpup 62 has a flat surface 70 that is at least partially exposed to the hot water, as shown by the dotted lines on the insert 50. Arrange the position to cooperate with Michi 52. The slope 69 extends outwardly from the edge 71 of the upper end surface 68 and also around the circumference of the saw blade 62 . The sloped surface 72 extends radially from the upper end surface 68 and the sloped surface 69, and is involved in the formation of a chute, that is, a recessed portion 73, which is a recessed portion in both surfaces. Incidentally, it is preferable that the chute 73 be inclined downwardly from the upper end surface 68 at an angle of about 45 degrees. These chutes 73 are located at four locations on the saw blade 62, as shown in FIG. The ramp 69, also referred to as a stop surface, seals or joins the bottom of the insert 50, as shown by the dotted line in FIG. As a result, the saw blade is fixedly held in a concentric position within the neck N of the headpiece. This type of seal is called a non-contact type. Thus, the stop or ramp 69 guides the insert 50 and the saw blade 62 into a mating position. As a result, a concentric orifice is defined within the neck N. The planes of the sawpup and die insert can vary, but must be oriented to provide concentricity, cut, and ease of entry of the thermoplastic 20 into the mold cavity 76. . The insert 50 provides a cover for each of the chute 73, thereby forming four corresponding passages 75. This passage 75 is the runner 5
2 to the inner wall 77 of the neck portion N. At least one passageway 75 and at least one sidewall opening 84 guide the thermoplastic material 20 into the mold cavity 7.
It is necessary to inject to 6. Hot water path 52
This combination of and passageway 75 is referred to herein as a conduit system. Thus, the neck portion N of the mold cavity 76 includes: an outer wall 78 defined by the neck plate 38; and an upper end wall with a sealing surface 80 defined by the bottom surface of the insert 50. Upper part 63 of sawpup 62 and insert 50
The inner wall 77 is defined by the inner wall 77 and the opening 84 communicating with the passage 75.
have at least one. In order to properly and effectively inject the thermoplastic material 20, the injection device 12 and the molding device 14 must be operated as shown in FIGS. 1, 3, and 4.
They must be coaxially aligned and connected. When the piston 22 extends, the thermoplastic material 20
Extruded into channel 28 and then into runner 52
Through a conduit system consisting of a series of passageways 75, a side wall opening 8 below a sealing surface 80 is provided.
4 and enters the mold cavity 76. Cavity part 7
The plastic material 20 in 6 is fused with a preformed plastic or laminate tube in a manner well known in the art. FIG. 3 shows a modified embodiment of the internal recessed runner system with a floating die insert assembly (general designation -86). In addition, the same floating die
Insert assembly 86 includes an inner die insert 92, an insert cap 90 thereon, and an outer die insert 88 circumferentially surrounding 90. Inner insert 92 is the same insert 9
2 is pressed against the slope 69 of the sawpup 62, it moves upward or downward within the outer insert 88, and the stroke of this vertical movement is due to the two springs in the insert cap 90 and the recess 95. Limited by Washer 94. Upon proper positioning of the male part 58 relative to the female part 32, the bottom of the inner insert 92 contacts the ramp 69 of the sawpup 62, thereby compressing the spring washer 94. When spring 94 is compressed, a reaction force is created on inner insert 92;
With this drag force, the inner insert 92 vs. the slope 6
9 is sealed, so the passage is cut off. When this sealing occurs, concentricity of the sawpap in turn occurs within the neck N. The use of floating die inserts 86 also reduces component assembly and balance problems due to increased tolerances. FIG. 4 shows an example of an application of the apparatus using an internally recessed runner in the headpiece mold and having a neck insert 96. This net insert 96 is pre-attached to the sawpup 62 prior to positioning the male part within the female part 32. The upper end surface 97 of the net insert 96 is located below the opening 84 in the inner wall 77 such that the thermoplastic material 20 conveyed through the passageway 75 enters the mold cavity through the same opening 84. I can do it. Figures 7 and 8 show another embodiment using an external runner system. There is a register pin 68 protruding from the sawpup 62 and occupying a central position, the pin 98 being aligned with a corresponding recess in the thread plate 100 and positioned above the sawpup 62 so as to be in the center of the neck N. 63 to cooperate correctly with the threaded plate 100. The solidified headpiece is then removed from the male part 58, and a concentric orifice is formed in the neck of the headpiece.
The orifice corresponds to the space previously occupied by the upper part 63 of the saw blade 62. Two sets of symmetrical passageways extend outwardly from the runners 52 within the threaded plate 100. One of them is indicated by a dotted line P. Each set of passages first has a passage 102 facing outward.
The passage 102 communicates with the runner 52 at one end,
The other end opens into an axial passageway 104 . Each of the passageways 104 in turn opens into an inwardly directed passageway 106, which in turn opens into the outer wall 78. This runner method is located outside the tube, so
This method is called the external runner injection mold method. Note that the following systems can be adopted in either of two ways, or they can be used in combination. That is, as shown by the dotted line P, the axial passage 10
4 can be extended to the shoulder of the cavity 76 and the thermoplastic material 20 can be filled into the cavity 76 through the opening 110 in the outer wall 78 of the shoulder. Preferably, the outlet of the runner 106 communicates with the outer wall of the neck N or shoulder. That is, it is preferable to provide an opening at a position above or below the threaded portion. Thus, a conduit system consisting of a series of runners 52 and passageways 75 conveys the thermoplastic material 20 to the outer wall 78 of the neck N, where the thermoplastic material passes through the opening 108 in that wall. It passes through and reaches the cavity 76. In addition, the following methods are adopted in an alternative method,
It can also be used in combination. That is, a conduit system consisting of a series of runners 52 and passageways serves to transport the thermoplastic material to the shoulder S, through which the thermoplastic material enters the outer wall through an opening in the shoulder S. It is. When the cavity 76 is filled during the injection cycle, either with an internal recessed runner system or an external runner system, the mold equipment falls away from the injection system, e.g., with a rotary table. , indexing throughout the drying cycle. At the end of the drying cycle, the molding equipment subjects the indexing to a pre-stripping step. In the same process, the female part is lifted and the tube with the head remains attached to the male part (not shown).
It should be noted that sufficient consideration has been given to the fact that thermoplastic protrusions corresponding to the shape of the conduit system used in the device remain attached to the side walls. It is sometimes noted that in the case of the internal runner system, the thermoplastic material protrusion remains attached to the inner wall, as shown in the remaining state 116 in FIG. As shown in the cut state 117 in the figure, it remains attached to the outer wall. In order to remove these protrusions while they remain attached to the sidewall, the external runner system requires opening the threaded plate 100 along the split plane, or seam running through the conduit system. is necessary. The internal runner method also uses a plate opening. The removal or lifting off of the male part may alternatively be accomplished in a different manner using the apparatus shown in FIGS. 1-6. The die insert is a runner of a certain length or
Having a runner that tapers from the outlet to the inlet allows it to be lifted away from the dry thermoplastic in the runner along with lifting of other female parts. Additionally, each runner has its own chute on the sawpup and its cover on the insert, so by separating and lifting the female part from the male part, these two parts can be placed on top of the sawpup. It is separated along the seam defined by the joint between the bottom surface of the insert and the bottom surface of the insert. On the other hand, the protrusion remains stuck in the opening of the inner wall. The stripping process then begins, during which the compressed air pushes the male part upwardly, the clamp grips the runner section of the protrusion, and pulls the headed tube out of the male part. The headed tube is conveyed by clamps to the core for runner removal and capping. FIG. 9 shows a method for removing the runner in the internal concave runner system shown in FIGS. 1 to 6. The headed tube H carried by the core for runner removal and capping enters the runner removal process. The circular positioning tool 112 then moves the headed tube onto the runner removal and capping core in conjunction with pushing the runner removal pin 113 into the neck N of the headed tube.
Let it hold. The end of the projection runner 75 is then cut through the inner wall 77 and the thermoplastic projection 115 is stripped from the head tube. The height of the runner removal pin 113 is important and strictly defined. The reason is that the top surface 114 must be sheared, while the headed tube H
This is because its final position within the capping process must not interfere with the capping process. This capping process is performed as the final process before packaging. FIG. 10 illustrates the method used for runner removal of the external runner system of FIGS. The tube H with the head is carried by the runner removal and capping core and enters the runner removal process. The positioning tool 112 then seats and holds the headed tube on the runner removal and capping core. The stripper 115 indicated by the dotted line is the protrusion 11
Grasp the runner section of the headed tube marked 7 and rotate until the protrusion is severed at 106 in the passage section of the outer wall 78. The use of the illustrated apparatus has been found to significantly increase the speed and efficiency of automatic injection molding equipment used in collapsible tube molding. As explained above, according to the present invention, since the opening of the injection extension is located on the side wall of the neck portion of the headpiece, the upper surface of the headpiece, that is, the sealing surface, is completely molded and finished smooth, and the concentric mouth hole is A headpiece with an orifice is obtained.

[Brief explanation of drawings]

FIG. 1 is an elevational sectional view of an injection molding apparatus of the present invention using an inner runner type, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, and FIG. 3 is an inner runner. FIG. 4 is an elevational cross-sectional view of the injection molding apparatus of the present invention using an inner runner type and a floating die insert.
FIG. 5 is a partial elevational cross-sectional view of an injection molding device of the present invention using an insert and a neck insert, and FIG.
FIG. 6 is a plan view thereof, and FIG. 7 is an elevational sectional view taken along the line 7-7 in FIG. , FIG. 8 is a sectional view taken along line 8-8 in FIG. 7, FIG. 9 is a front view showing removal of the sprue from the inner runner, and FIG. 10 is a front view showing removal of the sprue from the outer runner. In the figure, 58...Male part, 32...Female part,
76...Cavity, 80...Sealing surface, 78...Outer wall, 77...Inner wall, 84...Inlet opening, 20
... thermoplastic material, 52 ... runner, 75 ... passage.

Claims (1)

[Claims] 1. A device having an imaginary central axis, comprising an inner wall and a threaded outer wall, the two side walls being connected by a top wall with a sealing surface, and having an outlet concentric with respect to the central axis. Apparatus for injection molding a thermoplastic headpiece suitable for being welded to a preformed tubular body, the apparatus comprising: a neck portion forming a neck portion; and a shoulder portion; a mold part that, together with the male part, defines a cavity having a shape corresponding to the shape of the head piece to be formed; a female part having a runner within the neck of the cavity, at least a portion of which is above the upper end wall of the cavity, and having an inlet for receiving the thermoplastic in liquid form; It is formed by fitting the female and male parts together and is located between the two parts, one end of which communicates with the runner, and the other end of which communicates with the inside of the neck of the hollow part. It leads to the wall,
at least one passageway for conveying the liquid thermoplastic received from the runner into the cavity; and inserted into the neck of the headpiece, the passageway and an inner wall of the neck of the headpiece. cutting means for separating the solidified thermoplastic in the passageway near the contact point of the passageway; forming a headpiece with a flash-free top wall in the male part, the female part and the passageway; Thermoplastic headpiece injection molding equipment featuring: