JP4641142B2 - Screw structure of bottle opening - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw structure of a bottle opening applied to a bottle opening of a plastic bottle such as a plastic bottle or a glass bottle.
[0002]
[Prior art]
Conventionally, the screw structure of a bottle opening for beverages or the like is configured such that a female screw inside a cap is screwed into an opening in which a male screw is formed, and is sealed between the top of the cap. Some of these screw structures have a single-threaded structure, but the one-threaded structure requires at least one rotation to securely screw the cap onto the opening of the bottle. The rotation angle of the stopper was large. For this reason, a new proposal has been proposed in which the number of threads is large and the cap can be sealed and opened at a rotation angle of 1 rotation or less, for example, 1/2 to 1/4 rotation.
In relation to such a screw structure of the bottle opening portion, for example, in Patent Document 1, a part of the screw portion in the multi-thread screw is removed so that the screw portion is engaged with a small number of rotations. A screw structure is described.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-247818
[Problems to be solved by the invention]
However, the bottle opening screw structure described in Patent Document 1 has the following problems.
That is, when manufacturing plastic bottles and glass bottles, when a resin material or the like is molded using a mold, and then the mold is divided into left and right molds (mold removal), the thread at the bottle opening Since the inclined surface of the bottle is formed at a steep angle, the screw structure bottle with a large lead angle is in an undercut state at the bottle opening, making it difficult to mold the screw at the bottle opening. Problem arises.
If the molded body in which such an undercut portion is formed is forcibly punched out (forcibly removed), the thread structure of the bottle is deformed to become a defective product.
[0005]
The present invention has been made in order to solve the above-mentioned conventional problems, and provides a screw structure of a bottle opening portion that can be easily removed (not forcedly removed) when a molded bottle is released, and a cap. It aims at providing the screw structure of the bottle opening part excellent in the easy open property which can mount and open the cap at a small rotation angle.
[0006]
[Means for Solving the Problems]
(1) The screw structure of the bottle opening of the present invention made to solve the above problems is formed on the peripheral surface of the opening of the bottle made of plastic, glass, etc.
It has a multi-threaded screw with multiple threads on the peripheral surface of the opening of the bottle,
The cross section of the screw thread in the bottle axis direction is formed in an asymmetrical chevron shape including a gently inclined surface and a steeply inclined surface,
The gently inclined surface is formed on the opening side;
The steeply inclined surface is formed on the bottom side of the bottle;
A notch that divides the thread so that it intersects the direction of rotation,
In order to facilitate the die-cutting at the time of die-cutting , a pair is formed clockwise with a predetermined width with the parting line of the opening as a reference line,
The inclination angle θU of the gently inclined surface is 32 to 45 degrees, the inclination angle θD of the steeply inclined surface is 15 to 32 degrees, and the inclination angle θU> the inclination angle θD. And
As a result, it is possible to improve the die-cutting property of the molded body at the time of molding a plastic bottle or a glass bottle, and it is possible to provide a bottle with excellent productivity.
Moreover, by providing a notch part, it is possible to further facilitate die-cutting of a molded body after molding a plastic bottle having a thread or a glass bottle, and it is possible to further increase productivity when manufacturing the bottle.
Furthermore, the slackness of the cap can be suppressed by forming the steeply inclined surface of the screw thread on the bottle bottom side.
[0007]
Further, by configuring the inclination angle θU of the gently inclined surface, the inclination angle θD of the steeply inclined surface, and the inclination angle θU> the inclination angle θD,
It is possible to avoid an undercut state, to form a draft from the mold, and to prevent loosening of the screw when the cap is screwed.
[0008]
(2) The screw structure of the bottle opening of the present invention is characterized in that, in the above (1), the thread lead angle is in the range of 8 to 20 degrees . By making the rotation angle of the cap small, it is possible to maintain the screwing attachment property to the bottle opening in an appropriate range, and it is possible to obtain a screw structure of the bottle opening excellent in easy openness.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a front view of a bottle opening according to an embodiment of the present invention, and FIG. 2 is a plan view thereof.
FIG. 3 is a development explanatory view for further understanding the screw structure of the bottle opening, and FIG. 4 is an enlarged cross-sectional view of the screw thread of the bottle opening in the bottle axis direction.
1 and 2, 11 is a bottle opening showing a screw structure made of plastic such as polypropylene or polyethylene terephthalate, glass, etc., 12 is a screw thread made up of multiple threads formed around the opening 11, and 13. Is a gently inclined surface formed on the opening 11 side of each thread section, 14 is a steeply inclined surface formed on the bottle bottom side of the thread 12 (opposite side to the opening side), and 15a and 15b are openings. These are a pair of notches formed on the peripheral surface of the portion 11.
[0010]
Here, as shown in FIG. 1 and FIG. 2, the pair of notch portions includes a notch portion 15a having a parting line PL1 as a reference line and a notch portion 15b having a parting line PL2 as a reference line. Say.
3 and 4, E is the circumferential length of the developed thread forming portion, A is the width of the thread forming portion, and H is the width of the notch 15 a (15 b) where the thread 12 is not formed. , ΘL is the lead angle of the thread, θU is the inclination angle of the screw surface on the opening side (upper surface 13), and θD is the inclination angle of the screw surface on the bottle bottom side (lower surface 14).
[0011]
As the bottle having the screw structure of the present invention, plastics, glass and the like, each of which is molded using a known molding means can be applied. For example, when molding plastic bottle preforms with threads formed in the bottle openings, injection molding is performed by injecting a resin such as polyethylene terephthalate, which has been melted or softened at high temperatures, into a mold for molding. For example, a blow molding method in which a plastic bottle or the like is molded by blow-molding a preform molded body after the mold is divided into right and left parts after being cooled and cured, and then taken out and taken out.
[0012]
Generally, plastic bottles are formed by molding methods such as blow molding after molding a preform body by injection molding, but due to the thread ridges when the preform body is pulled out of the split mold for molding. The mold and bottle structure for molding must be designed in consideration of the undercut condition.
That is, when an undercut portion exists in the screw portion of the bottle opening, the molding die is divided into left and right with reference to the parting line (PL1, PL2 in FIG. 2) (arrows p and q in FIG. 1). Direction) When the molded product bottle is extracted, there is a problem in that it interferes with the mold and causes deformation such as distortion and dent in the thread ridge of the bottle opening that is still semi-softened.
[0013]
Therefore, in the bottle having the screw structure of the present embodiment, the thread 12 is formed with the gently inclined surface 13 and the notch 15a, so that when the preform molding is extracted from the molding die, the screw The protruding portion of the mountain can be punched without interfering with the mold, and deformation such as distortion and dent can be avoided in the screw structure.
In other words, the screw structure of the bottle opening portion is divided into the left and right directions (parts indicated by arrows p and q in FIG. 1) with the parting lines (PL1 and PL2) being divided lines when the mold is divided into left and right parts and the preform molded body is extracted. ), The thread formed on the bottle opening is formed with a gently sloping surface on the upper surface, and the left side area (adjacent left side area L) adjacent to the parting line (PL1, PL2). ) Was formed so as to reduce the interference effect when the molded body was extracted.
[0014]
More specifically, in the right side region (adjacent left side region R) adjacent to the parting line (PL1, PL2) of the screw structure of the bottle opening, the upper surface 13 of the thread 12 is undercut when the die is removed. There is a risk of forming a cut, and the lower surface 14 of the thread 12 does not have the risk of forming an undercut upon die cutting.
That is, since the lead angle θL of the screw thread 12 is increased in the clockwise direction, in the adjacent right region R of the parting line (PL1, PL2), the screw thread upper surface 13 is in an undercut state at the time of die cutting. become.
Therefore, in order to avoid an undercut state in the adjacent right region R, the angle of inclination of the upper surface 13 of the thread is made gentle (the inclination angle θU in FIG. 4 is increased), thereby reducing the slipping gradient from the mold. Can be formed.
On the other hand, in this adjacent right region R, the lower surface 14 of the thread 12 does not become an undercut state at the time of die-cutting, so it is not necessary to make the angle of the thread inclined surface a gentle slope. From the viewpoint of loosening of the screw when the cap is screwed, it is preferable to make the angle of inclination steep (decrease the inclination angle θD in FIG. 4).
[0015]
Further, in the left side region (adjacent left side region L) adjacent to the parting line (PL1, PL2) of the screw structure of the bottle opening, there is a possibility that the lower surface 14 of the screw thread 12 forms an undercut when the die is removed. Yes, the upper surface 13 of the thread 12 has no fear of forming an undercut during die cutting. Therefore, if the lower surface 14 of the screw thread 12 is a steeply inclined surface, the protruding part of the screw thread may interfere with the mold during die cutting, but the left side area adjacent to the parting line (PL1, PL2). Since the notch 15a is formed in L, the possibility that the protruding portion of the screw thread interferes with the forming die during die cutting is reduced.
[0016]
For the above reason, in the present embodiment, the gently inclined surface 13 of the screw thread 12 is a surface orthogonal to the bottle axis direction (horizontal plane in the drawing) as shown in the thread enlarged sectional view in the bottle axis direction of FIG. ) With an upward inclination angle θU of 32 to 45 degrees, more preferably 35 to 45 degrees, while the steeply inclined surface 14 has a downward inclination angle θD of 15 It is formed so as to be ˜32 degrees, and the inclination angle θU> the inclination angle θD. That is, the cross section of the screw thread 12 has an asymmetric chevron shape.
If the inclination angle θU of the gently inclined surface is less than 32 degrees, it becomes difficult to remove the molded product. On the other hand, if the inclination angle θD of the steeply inclined surface exceeds 32 degrees, the cap tends to be loosened. The set angle is within a preferred range.
[0017]
Next, the notch 15a will be described. In the present embodiment, a notch 15a (or 15b) is formed in the left side region L adjacent to the parting line (PL1, PL2) of the screw structure of the bottle opening.
The notch 15a (or 15b) is a state in which the protrusions of the screw thread 12 are cut from the screw forming part of the opening 11, and the screw thread 12 is divided so as to cross the rotation direction, and the bottle It is formed in the direction of the axis 16. The tip of the thread 12 following the notches (15a, 15b) has cut portions f1, f2 cut in the tangential direction at the position of the parting line (PL1, PL2) on the outer surface of the bottle opening 11. . In the present embodiment, the width H of the cutout is the total length of the cutout 15a (or 15b) and the cutout f1 (or f2) following the cutout.
Further, in the present embodiment, the direction intersecting with the rotation direction of the screw thread 12 is preferably the same direction as the bottle axis 16 direction (vertical direction) from the viewpoint of die-cutting property.
[0018]
When the left side region L adjacent to the parting line (PL1, PL2) is punched, the lower surface 14 of the thread 12 formed on the steeply inclined surface is undercut, but in the vicinity of the parting line (PL1, PL2). Since the thread is not formed on the surface and the notches 15a and 15b having a predetermined width H are formed, the mold can be removed without interfering with the thread during the mold separation or with minimal interference. It can be done easily.
Note that the width H of the notch 15a (or 15b) is set in consideration of the mold-pullability toward the arrow p side, and the bottle mouth outer diameter (the diameter of the bottle opening), the lead angle θL. However, it is preferable to set the dimension to 2.5% to 10% of the circumferential length E of the screw forming portion.
The reason for this is that if the width H of the notch 15a (or 15b) is narrower than 2.5% of the circumferential length E, interference with the mold tends to occur when the molded body is extracted from the mold, and conversely This is because if the width exceeds 10%, the engagement with the threaded portion of the cap that is screwed into the bottle opening is extremely reduced, and the cap mounting property is deteriorated or loosened easily.
[0019]
As shown in the figure, in the present embodiment, the screw structure of the bottle opening is a multi-threaded screw composed of 6 threads, and the lead angle θL of these threads 12 is in the range of 8 to 20 degrees. The notches 15a and 15b are formed in pairs (two locations) clockwise (in the direction of the arrow t in FIG. 1) with the split parting lines (PL1 and PL2) as the reference line.
“Using the parting line as a reference line” means that the notching portions 15a and 15b are formed with a predetermined width H in the clockwise direction in FIG.
Here, when the lead angle θL of the screw thread is less than 8 degrees, the tendency of the cap to be easily opened at the time of opening appears, and conversely, when it exceeds 20 degrees, the cap tends to be loosened. Is unfavorable because of the increase.
[0020]
In the present embodiment, the number of screws disposed in the screw forming portion, the bottle mouth outer diameter, the width H of the notches 15a and 15b, the lead angle θL of the screw thread, and the inclination angle θU of the upper surface 13 and the lower surface 14 of the screw thread. , ΘD can be experimentally evaluated and set to each optimum range in consideration of factors such as cap mounting ease, cap looseness, and ease of mold release after molding.
Thus, depending on the circumferential length E and the width A of the screw forming portion, the number of screw threads 12 for forming a multi-thread screw, the lead angle θL, the width H of the notches 15a and 15b, and the inclination of the screw thread 12 By appropriately changing the angles θU and θD, defects that occur during mold separation are suppressed.
[0021]
FIG. 5 is an explanatory diagram showing an example of a screwed state between the screw forming portion of the bottle opening and the cap attached to the bottle opening 11.
In FIG. 5, B is a cap provided with a female screw portion screwed into a male screw of the bottle opening portion, C is a screw inclined surface on the upper surface (opening side) of the female screw of the cap B, and D is a female screw of the cap B. It is a screw inclined surface of the lower surface (bottle bottom side) of the screw.
As shown in the figure, when the cap B is attached, the screw inclined surface C of the cap B has a steep inclination of the thread 12 of the bottle opening with respect to the inclination angles θU and θD of the thread in the screw structure of the bottle opening. Since it is restrained by the surface 14, the cap B is less likely to be loosened.
[0022]
As described above, in the screw structure of the bottle opening portion of the present embodiment, since the cross section of the screw thread 12 is formed in an asymmetrical chevron shape, it is easy to remove the mold when molding a plastic bottle or a glass bottle. Therefore, productivity can be improved and cap can be easily attached and opened by increasing the lead angle θL.
Furthermore, notches 15a and 15b are provided to divide the thread 12 of the multi-threaded screw with a predetermined width H so as to cross the rotation direction, and these notches 15a and 15b are preforms for plastic bottles and glass bottles. Since the parting line of the divided mold at the time of molding is positioned so as to be a reference line, the molded body provided with the thread 12 can be easily removed from the mold, so that the productivity in bottle manufacturing is excellent.
Further, by setting the angles of the inclined surfaces 13 and 14 of the screw thread 12 to a specific range and setting the lead angle θL to an appropriate range, it is possible to balance the adhesion with the cap screw and the operability of mounting.
[0023]
In addition, in the screw structure 10 of the bottle opening part of the said embodiment, although the bottle made from a plastic was demonstrated as an example, this invention is not limited to these, It applies similarly also to a glass bottle. Can do. Further, there is no reason to limit the number of thread threads to 6 or the like, and the present invention can be applied to a general multi-threaded thread such as a 3-thread thread.
[0024]
【The invention's effect】
According to the screw structure of the bottle opening according to claim 1,
It has a multi-threaded screw with multiple threads on the peripheral surface of the opening of the bottle,
The cross section of the screw thread in the bottle axis direction is formed in an asymmetrical chevron shape including a gently inclined surface and a steeply inclined surface,
The gently inclined surface is formed on the opening side;
The steeply inclined surface is formed on the bottom side of the bottle;
A notch that divides the thread so that it intersects the direction of rotation,
In order to facilitate the die-cutting at the time of die-cutting , a pair is formed clockwise with a predetermined width with the parting line of the opening as a reference line,
Since the inclination angle of the gently inclined surface is 32 to 45 degrees, the inclination angle of the steeply inclined surface is 15 to 32 degrees, and the inclination angle θU> the inclination angle θD, the plastic bottle or glass It is possible to improve the die-cutting property of the molded body at the time of preforming the bottle and to provide a bottle with excellent productivity.
In addition, by providing a notch, it is possible to further facilitate the die-cutting of the molded body after preform molding of plastic bottles and glass bottles with threads, and to further increase the productivity when manufacturing the bottles. it can.
Furthermore, the slackness of the cap can be suppressed by forming the steeply inclined surface of the screw thread on the bottle bottom side.
[0025]
According to the screw structure of the bottle opening according to claim 2,
Since the lead angle of the thread is in the range of 8-20 degrees,
By making the rotation angle of the cap small, it is possible to maintain the screwing attachment property to the bottle opening in an appropriate range, and it is possible to obtain a screw structure of the bottle opening excellent in easy openness.
[Brief description of the drawings]
FIG. 1 is a front view of a screw structure of a bottle opening according to an embodiment of the present invention.
FIG. 2 is a plan view of a screw structure of a bottle opening according to an embodiment of the present invention.
FIG. 3 is a development explanatory view of a screw structure of a bottle opening according to an embodiment of the present invention.
FIG. 4 is an enlarged cross-sectional view of the thread in the bottle axis direction of the screw structure of the bottle opening according to the embodiment of the present invention.
FIG. 5 is an explanatory view showing a screwed state of the bottle opening and the cap according to the embodiment of the present invention.
[Explanation of symbols]
11 Opening 12 Thread 13 Slightly inclined surface (upper surface)
14 Steeply inclined surface (bottom surface)
15a, 15b Notch 16 Bottle axis L Adjacent left region R Adjacent right region t Clockwise direction A Thread forming part width E Thread forming part circumferential length H Notch part width PL1, PL2 Parting Line B Cap C, D Cap screw inclined surface θL, θU, θD Inclination angle

Claims (2)

The bottle has a multi-threaded screw with a plurality of threads on the peripheral surface of the opening of the bottle, and the cross section in the bottle axial direction of the thread is formed in an asymmetrical mountain shape composed of a gently inclined surface and a steeply inclined surface. ,
The gently inclined surface is formed on the opening side;
The steeply inclined surface is formed on the bottom side of the bottle;
A notch that divides the thread so that it intersects the direction of rotation,
In order to facilitate the die-cutting at the time of die-cutting , a pair is formed clockwise with a predetermined width with the parting line of the opening as a reference line,
The inclination angle θU of the gently inclined surface is 32 to 45 degrees, the inclination angle θD of the steeply inclined surface is 15 to 32 degrees, and the inclination angle θU> the inclination angle θD. The screw structure of the bottle opening. The screw structure of the bottle opening according to claim 1, wherein a lead angle of the thread is in a range of 8 to 20 degrees.

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