JP2015020756A - Container with lock function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-productivity and inexpensive provision of a container that has a child-proof mechanism incapable of being easily opened by an infant and that hardly causes a molding error and a change caused by variations.SOLUTION: A container with a lock function, which can be opened/closed by screwing, comprises a container body (2) and a cap (1). A container body screw part (22) has a notch (221). A movable protrusion (3) capable of being engaged with/disengaged from the notch is formed integrally with the cap.

Description

  INDUSTRIAL APPLICABILITY The present invention is used for containers for storing powders, granules, and liquids such as pesticides, repellents such as mice and cats, insecticides such as cockroaches, shirami, and moths, preservatives, organic solvents, bleaching agents, and detergents. The present invention relates to a container in which a container body and a cap are screwed, and to a container with a child proof function (lock function) that cannot be easily opened by an infant.

Agricultural chemicals, repellents such as mice and cats, insecticides such as cockroaches, shirami, and moths, preservatives, organic solvents, bleaching agents, detergents, other prescription drugs, and detergents are very large if children accidentally eat and drink. There is a demand for a child proof function that can be opened easily by infants and infants in products that are likely to cause health hazards.
For example, in Patent Document 1, a child proof in which a lower portion is extended with a large diameter below a thread and an engagement protrusion that can be engaged with a corresponding engagement protrusion on an outer surface of a container mouth portion is provided on the inner surface of the extension portion. Proposed bottle caps (child proof in literature).
Since this bottle cap must be engaged with the engaging protrusion at the time of final rotation, this engaging portion is set so that the protrusion is engaged smaller than the screw pitch by an amount corresponding to the gap in the vertical direction. I have to.
However, for plastic screws, the strength of the thread must be increased, and the screw valley width should be larger than the thread width at the bottom of the cap so that it can be easily removed by rotating from the mold. I must. In addition, the part forming the screw of the container has the largest shrinkage due to molding, and errors in the pitch direction are likely to occur, and there are many restrictions such as the gradient of the thread tip and the gradient of the screw width. The gap is large, and the number of engagement spots with which the engagement protrusions are engaged is inevitably reduced. In addition, plastic is rich in elasticity, and if a large force is applied below the cap, it may be easily deformed and get over the extension.
Therefore, with this engagement, it is very difficult to completely lock and make it difficult for a child to open.
Moreover, since errors in the pitch direction are likely to occur, it is often necessary to bury the position of the extended part where the mold is processed, and the molding conditions are greatly limited (many), and the productivity is low (bad). There was also a problem.

In Patent Document 2, a cylindrical mouth plug body having a hook-shaped portion on the lower end outer wall, and a hat-like shape that is helically fitted to the outer wall of the cylindrical mouth plug body and rotated to open and close. In a plastic spout stopper that is attached to a liquid paper container and has a cap, a locking projection is provided on the lower outer wall of the cylindrical mouth plug, and a cap-shaped cap is attached to the lower part of the cap-shaped cap. A child proof spout plug is provided which is provided with a fitting notch that fits with a locking projection when rotated and completely closed.
This spout plug also has a fitting notch provided at the bottom of the cap, where errors such as molding shrinkage are likely to be greatly affected, and errors in the pitch direction are likely to occur. Since there are many restrictions such as a gradient, the vertical gap is large, and there is inevitably a small amount of engagement white where the engagement protrusion engages. In addition, plastic is highly elastic, and if a force is applied at the lower part of the cap, it may be easily deformed and get over the locking projection. For this reason, even if it was a child, it was not easy to open, and it could be easily opened.
In addition, errors in the pitch direction occur, and it is often necessary to fill and dig up the position of the extended part where the mold is processed, and the restrictions on the molding conditions are large (many) and the productivity is low (bad). There was also a problem.

Japanese Utility Model Publication No. 4-53649 JP-A-9-142502

  In view of the above problems, it is possible to provide a container having a child-proof mechanism that cannot be easily opened by infants and difficult to change due to molding errors and variations, with high productivity and at low cost. It is the subject of the present invention.

The container of claim 1 of the present invention is a container comprising a container body and a cap that can be opened and closed by screwing.
Has a notch in the container body thread,
The container with a locking function is characterized in that a movable protrusion that can be engaged and disengaged in the notch is formed integrally with the cap.

  The container according to claim 2 of the present invention is the container with a lock function according to claim 1, wherein the notch is machined into a screw portion near the tip of the mouth.

In the container of claim 3 of the present invention, the movable protrusion is a disk-shaped movable protrusion, and between the disk-shaped movable protrusion and the cap top surface,
The side shape is a truncated cone or a polygonal frustum, and the upper and lower sides are linear hinge portions, formed from a disc spring whose cone surface is inverted,
The container with a lock function according to claim 1 or 2, wherein the protrusion of the disk-shaped movable protrusion can be inserted into or removed from the threaded portion by reversing the disc spring.

In the container according to claim 4 of the present invention, the movable protrusion formed on the top surface of the cap is:
It is a disc spring movable projection that is formed from a disc spring with a conical surface or a polygonal frustum whose upper side is a linear hinge and the cone surface is inverted, and a projection is provided on the lower surface of the disc spring.
The container with a lock function according to claim 1 or 2, wherein the projection of the disc spring movable projection can be inserted into or extracted from the threaded portion by reversing the disc spring.

In the container of the present invention, after the cap is screwed into the container, the movable protrusion provided on the cap is pushed into the container, and the movable protrusion is engaged with the notch of the container body screw portion, whereby the cap is locked to the container body. Even if the cap is rotated as it is to open the cap, the cap does not rotate and the child proof mechanism can be exhibited.
Moreover, in the method of the present invention, since a notch that engages in the vicinity of the tip of the container mouth is provided, the position of the engagement does not greatly deviate even if the container production conditions are not strictly controlled, and the productivity is high. A child proof mechanism can be provided.

It is an external view of the container with a lock function of this invention, FIG. 1-1 is a figure of the state which fitted the cap, FIG. 1-2 is a figure which shows the state of the spout vicinity of a container main body. In a container with a lock function of the present invention, it is a sectional view in the state where a cap was fitted in a container. In the container with a locking function of the present invention, it is a sectional view in a state where the movable protrusion of the cap that has been engaged with the container body is removed from the notch of the male thread portion of the container body. In the container with a locking function of the present invention, it is a cross-sectional view showing a state in the middle of rotating and removing the cap screwed into the container body. It is sectional drawing which shows the shaping die structure of the cap used for the container with a lock function of this invention. It is sectional drawing which shows the condition which is sliding the piece of a movable protrusion part after injection molding with the shaping | molding die of the cap used for the container with a lock function of this invention. It is sectional drawing which shows the condition which is mold-opening the cavity side in the molding die of the cap used for the container with a locking function of this invention, leaving the back part piece of a movable protrusion with a holddown mechanism. It is sectional drawing which shows the condition which extracted the cap from the cavity side whole with the shaping die of the cap used for the container with a lock function of this invention. In the cap mold used for the container with a lock function of the present invention, the rotation stop portion at the lower end of the cap pushes out the cap according to the pitch at which the piece of the inner screw portion of the cap rotates, and the cap comes off from the mold. It is sectional drawing which shows the situation which is going. FIG. 5 is a cross-sectional view showing a state in which the cap is removed from the inner screw piece and the cap is protruded from the mold by the stripper plate in the mold for the cap used in the container with a lock function of the present invention. It is a cap used for the container with a lock function of the present invention, and is a sectional view of a type in which a movable projection is provided on the side surface of the cap, and a plan view seen from above. In the container with a locking function of the present invention, in the type in which the movable protrusion is provided on the side surface of the cap, the sectional view of the state in which the movable protrusion of the cap engaged with the container body is removed from the notch of the male thread portion of the container body is there. In the container with a locking function of the present invention, in the type in which the movable protrusion is provided on the side surface of the cap, it is a cross-sectional view showing a state in the middle of rotating and removing the cap screwed into the container body. It is sectional drawing which shows the structure of the metal mold | die in the type with which the movable protrusion was provided in the cap side surface side with the container with a locking function of this invention. It is an external view of the container in the cap by which the movable protrusion and the cap top surface were connected with the disc spring by the container with a locking function of this invention. It is sectional drawing of the locked state of the container in the cap with which the movable protrusion and the cap top surface were connected with the disc spring by the container with a locking function of this invention. It is sectional drawing of the lock release state of the container in the cap with the lock | rock function of this invention in which the movable protrusion and the cap top surface were connected with the disk spring. It is a metal mold | die sectional view which manufactures the cap of the container in the cap with a lock | rock function of this invention in which the movable protrusion and the cap top surface were connected with the disc spring. In the container with a locking function of the present invention, it is a cross-sectional view showing a locked state in an example of a disc spring movable projection in which the whole disc spring is a movable projection. In the container with a locking function of the present invention, it is an example of a disc spring movable projection in which the whole disc spring is a movable projection, and is a cross-sectional view in a state where the lock is released.

Hereinafter, the example of embodiment of the container with a lock function of the present invention is described in detail using a figure.
<First Embodiment>
FIG. 1-1 is an external view showing an example of a container with a lock function according to the present invention. A cap 1 is screwed into the container body 2, and the cap 1 is provided with a movable projection 3 on the top surface side.
FIG. 1-2 shows the vicinity of the spout of the container body 2, and the threaded portion 22 provided outside the spout 21 is provided with a notch 221. The notch width 222 is set according to the width of the protrusion tip 31 of the movable protrusion 3.
In the case of a blow container, the notch 221 can be processed when the spout 21 is injected during parison injection molding or when a blow pin is driven into a direct blow molding parison. Even extruded tubes are manufactured during injection molding.
Usually, the manufacture of these spout 21 portions is carved into a cavity side mold that can be opened and closed outward. In the manufacture of the cavity side mold, a normal male screw without a notch is first manufactured in a discharge master used for processing a screw thread. Then, the tip end side of the spout of the screw is cut out in accordance with the width of the tip of the movable protrusion, and the discharge master is used to perform discharge machining into a cavity mold. By doing so, the notch 221 can be easily processed into the male screw portion 22. Alternatively, it may be cut directly into a mold by a multi-axis machining center having four or more axes.
Of course, such a notch portion is a screw portion that is in the opening / closing direction of the mold, and is processed on the first circumference of the spout tip side.

FIG. 2 is a cross-sectional view showing a state in which the cap 1 and the container main body 2 are screwed together, as an example of the container with a locking function of the present invention.
The movable protrusion 3 is fitted in the notch 221 of the male threaded portion 22 of the container body 2. The cap 1 in FIG. 2 is provided with a fitting hole 11 in the vicinity of the corner between the top surface and the side surface, and a movable projection 3 on the top surface side, and a notch 221 on the container body side, and a spout 21. Is provided in the male screw portion 22 in the vicinity of the tip.
The movable protrusion 3 of the cap 1 is connected to the top surface of the cap at a junction 31 and is set to be rotatable by a central hinge 311 and a root hinge 312 at the tip. And the protrusion 32 is provided in the inner surface side of a movable protrusion, and the collar 33 for hooking a nail | claw etc. and removing is provided in the movable protrusion front-end | tip.
The protrusion 32 is provided with an engaging claw 321 in the middle of the length of the protrusion so that the movable protrusion 3 does not come out naturally.
The inner ring 12 of the cap 1 is fitted to the inner surface of the container main body 2 spout, and the contact ring 13 abuts the tip of the spout 21 to block the inside and outside of the container, and the contents leak, The inflow of gas can be set in the same manner as in a normal container.

FIG. 3 shows that the movable protrusion 3 of the cap 1 is hooked with a nail or the like on the flange 33, and the protrusion 32 is pulled out as shown by the broken line. The fitting of the movable protrusion 3 comes out of the notch 221, and the lock is released. ing.
When the lock is released, a force sufficient to overcome the engaging claw 321 provided in the middle of the protrusion 32 is required. Further, the central hinge 311 and the root hinge 312 are rotated so that they can be pulled upward.
When the tip of the protrusion 32 of the movable protrusion 3 comes out of the fitting hole 11, the central hinge 311 extends to be in a state of reliably protruding to the outside of the cap, and does not enter and the lock is reliably released. Will keep.
Since the inner ring 12 and the contact ring 13 are provided on the inner side of the fitting hole 11, the contents are basically in direct contact with the fitting hole 11 and the movable protrusion 3, or the dirt is stained. It is not designed to be.

In FIG. 4, since the lock is released, the cap 1 screwed into the container body 2 includes a male screw portion 22 provided around the spout 21, a knurl 14 provided around the cap, and an internal female screw. The state where it is rotated using the part 15 and is detached from the container spout 21 is shown.
The unlocked cap can be opened and closed in the same manner as a normal screwed cap. Of course, after the cap 1 is screwed, the movable protrusion 3 can be inserted again into the fitting hole 11 to be locked.

FIG. 5 shows an example of an injection mold for manufacturing the cap 1 of the present invention.
The cavity 4 of the cap 1 includes a core 410 and a rotating core 411, a rotation stopper 412, a stripper plate 413, and the like provided around the core 410, and is a normal movable side.
However, the fixed-side mold 42 is provided with a lateral slide 421 and a hold-down piece 422 in the fixed-side cavity 420. However, the hold-down piece 422 is not necessary depending on the shape.
The horizontal slide 421 is indispensable because the movable protrusion 3 is lifted unless it moves before the mold opening starts and the undercut is removed.
The horizontal slide 421 and the rotary core 411 form the fitting hole 11 by pushing.

FIG. 6 shows a state in which the injection mold for manufacturing the cap 1 starts to open the mold.
The horizontal slide 421 forming the fitting hole 14 is moved by pushing and moving away from the push-cut portion, and comes off from the protrusion 32 of the movable protrusion 3 so that the movable protrusion 3 is not lifted by the horizontal slide 421.

FIG. 7 shows a state where the core 410 and the rotating core 411 of the movable mold 41 start moving while holding the cap 1. At this time, the hold-down piece 422 also moves with the cap 1 and supports the outer surface of the movable protrusion 3.
The hold-down piece 422 moves together with the cap 1 until the inner surface side of the movable protrusion 3 is completely separated from the mold, and stops moving there.

FIG. 8 shows a state where the movable side mold 41 is moved and opened until the molded product is completely removed from the fixed side mold 42.
The cap 1 that is a molded product is still in close contact with the mold of the movable mold 41.

FIG. 9 shows a state where the movable-side core 410 and the rotary core 411 are moved in accordance with the rotation of the rotary core 411 and the screw pitch, and the injection-molded product is removed from the core 410 and the rotary core 411.
The rotary core 411 may be configured such that the rack and pinion are fitted to the movable mold fixing plate side to rotate the mold opening, or may be simply rotated by a motor whose speed can be adjusted. Absent.
At this time, the rotation stop 412 and the stripper plate 413 of the movable side mold 41 are not moved, and the cap 1 is held so that the cap 1 does not rotate according to the rotary core 411.

  FIG. 10 shows a state where the stripper plate 413 is pushed up and the molded product is removed from the rotation stopper 412 in a state where the screw portion of the rotary core 411 is completely removed from the molded product. At this time, when the mold is a horizontal injection molding machine, the molded product can be freely dropped from the mold, but it is preferable that the mold is sucked by the robot and taken out from the mold so that the movable protrusion 3 is not deformed. The hinge portion of the movable projection 3 is preferably adjusted so that the molecules are aligned by opening and closing immediately after molding and turning.

<Second Embodiment>
As another example of the present invention, another example in which the movable protrusion 3 is provided on the side surface of the cap 1 is shown in FIG.
FIG. 11A is a cross-sectional view seen from the side surface side, where the junction point 31 is provided on the side surface of the cap 1 and the side hinge 313 is provided following the junction point. The side hinge 313 is thin and can be turned. However, even if the thin part is long and the hinge bends as a whole, the side hinge 313 is also short and acute. It doesn't matter.

FIG. 11B is a plan view seen from the top surface side, and the side surface engaging claws 32 provided on the side surface of the protrusion 32.
2 is engaged with the fitting hole 11 and fixed.
The shape of the knurl 14 provided around the cap 1 may be triangular, semicircular, or trapezoidal, but it is for rotating the cap 1 and screwing it.
Since the shape of the rotation stopper 412 is general, it is not clearly shown, but it is set on the surface of the lower end of the cap so as not to rotate only in the direction of the screw like a continuous triangular roof.

  FIG. 12 shows a state in which the protrusion 32 of the movable protrusion 3 on the side surface is detached from the notch 221 of the male screw portion 22 and unlocked. Thus, when the movable protrusion is provided on the side surface, the shape can be simple.

  FIG. 13 is a cross-sectional view showing a state where the unlocked cap 1 is turned to start removing the cap 1.

FIG. 14 shows an example of a cap injection mold in which the movable protrusion 3 is provided on the side surface of the cap 1.
Although a gate is not described, a pin gate is preferable.
Also in the case of this mold, if the product is grasped by the robot and the product is completely transferred to the robot by the protrusion of the stripper plate, it is easy to proceed to the next folding process of the hinge portion.
The process for producing the container of the present invention is as described above, and can be processed with a normal injection molding machine with a single mold, and does not require assembly of different types of parts. Therefore, it is inexpensive and has high productivity.

<Third Embodiment>
In FIG. 15, the shape of the movable protrusion is a disk-shaped movable protrusion 30 having a disk-shaped ring, and between the disk-shaped movable protrusion 30 and the top surface of the cap 1,
This is an example in which the upper side and the lower side of the truncated cone having a truncated cone shape or a polygonal shape are composed of a linear upper side hinge 315 and a lower side hinge 316, and the cap is formed of a disc spring 314 whose cone surface is reversed.
In the lower part of the disc-shaped movable protrusion 30, one to four, preferably one or two, protrusions 32 are provided, and the fitting hole 11 is provided on the top surface side of the cap screw part according to the position. Yes.
As the disc spring 314 is inverted, the disc-shaped ring 30 of the disc-shaped movable projection moves up and down, so that the projection 32 is inserted into or extracted from the threaded portion notch 221 by the movement.
FIG. 15A shows a state in which the protrusion 32 is inserted into the threaded portion notch 221 and locked.
FIG. 15-2 shows a state where the lock is released and the disk-shaped ring of the disk-shaped movable protrusion 30 is raised.

FIG. 16 shows a disk-shaped movable protrusion 30 and a disc spring 314 in which the upper side and the lower side of the frustum whose side shape is a truncated cone or a polygon are linear upper side hinges 315 and lower side hinges 316, and the conical surface is inverted. The state in which the cap was locked to the container is shown by sectional drawing. The disk-shaped ring of the disk-shaped movable protrusion 30 is horizontal, and a disk-shaped ring is provided by a joint point 31 provided in a circle on the top surface of the cap 1, an upper side hinge 315, a disc spring 314, and a lower side hinge 316. A protrusion 32 provided on the lower surface of the ring-shaped ring passes through the fitting hole 11 and is inserted into the notch 221 of the container screw portion 22.
The disc spring 314 is locked so that the lower hinge 316 is on the lower side and the disc-shaped ring is positioned on the lower side by the spring force.

FIG. 17 is a sectional view showing a state where the disk-shaped movable protrusion 30 is raised upward and the lock is released.
Even when unlocked, the disk-shaped ring of the disk-shaped movable protrusion 30 is horizontal and raised upward, and the protrusion 32 provided on the lower surface of the disk-shaped ring comes out of the fitting hole 11 and the notch of the container screw part 22 is cut out. The screw detaches from 221 and can be rotated.
The disc spring 314 is held so that the lower hinge 316 is on the upper side and the disc-shaped ring is positioned on the upper side by the spring force of the disc spring.

FIG. 18 shows a disk-shaped movable protrusion 30 and a disc spring 314 in which the upper side and the lower side of the truncated cone having a truncated cone shape or a polygonal shape are linear upper side hinges 315 and lower side hinges 316 and the cone surface is inverted. It is sectional drawing which showed an example of the manufacture metal mold | die of a cap.
In addition to the horizontal slide 421 that removes the undercut of the fitting hole 11, the front / rear direction slide 423 shown in the figure that removes the lower surface side of the disc-like movable protrusion 30 is actuated, and the undercut of the disc-like movable protrusion is removed.
The upper side hinge 315 is carved in the slide, but the lower side hinge 316 is carved in the fixed side mold 42 so as not to cause an undercut.
The movement of the movable mold 41 is the same as that shown in FIGS.

<Fourth Embodiment>
FIG. 19 is an example of a disc spring movable projection 317 in which the whole disc spring is a movable projection, and is a cross-sectional view showing a locked state.
With the disc spring movable protrusion 317, when the outer periphery of the disc spring movable protrusion is lifted, the disc spring movable protrusion 317 is turned upside down so that it rotates around the upper hinge 315 in the sectional view, and the lock is made as shown in FIG. To release.
The disc spring part needs to be flexible so that it can be turned upside down, so it cannot be made too thick.
The mold can be injection-molded with almost the same mold as in FIG.

The injection molding resin used for the cap 1 is preferably a crystalline resin that easily obtains the strength of the hinge, and the movable protrusion 3 is required to have some rigidity, so that a random copolymer resin of ethylene and polypropylene is used. Or a block copolymer resin, linear low-density polyethylene, or a mixed resin thereof is preferable, and among them, a grade having high fluidity is preferable so that it can be easily molded through a thin portion such as a hinge.
Depending on the contents and usage environment, a mixed resin to which an ethylene vinyl acetate copolymer resin, an ethylene acrylic acid copolymer resin, or the like is added, or a polymethylpentene resin may be used.
In actual use, after molding using a resin to be adopted, it is fitted into the container body, and the content to be filled is used to conduct an environmental stress cracking test to make a judgment.

The molding resin used for the container body 2 is preferably a resin different from the cap, but it is also necessary to be a resin that is less susceptible to environmental stress with the contents.
For example, it may be a container obtained by stretch-blow molding a parison injection-molded with polyethylene terephthalate resin, or may be a container obtained by direct blow molding of a high-density polyethylene resin. In addition, blow molding resins such as acrylonitrile resin, polyphenylene resin, and polycarbonate resin are also used.
Furthermore, in the case of a tube container, a laminate film may be used for the main body structure and polyethylene may be injection-molded on the shoulder portion, a polyethylene single-layer tube main body, a polyamide resin, an ethylene-vinyl alcohol copolymer, etc. It may be an extruded tube using a multilayer extruded tube in which is put in an intermediate layer or an outer layer.
However, when the number of screws is many, it is necessary to provide notches 221 corresponding to the number of the threads.

The container with a lock function of the present invention is as described above. For containers that contain contents that are likely to cause an accident when an infant accidentally opens them, such as pharmaceuticals, detergents, and bleaches, Since the lock mechanism is designed in the vicinity, it is possible to provide a stable lock mechanism that hardly causes variations due to molding of the container main body and the cap, so that an accident can be efficiently prevented.
Further, it can be molded by a normal injection molding machine, and the cap can be manufactured with only one shot, so that complicated assembly is not required, so that productivity is high.
Furthermore, the container body can be dealt with by changing or remodeling the mold by ordinary blow molding or injection molding, which is very advantageous.

1 ... cap 11 ... fitting hole 12 ... inner ring 13 ... contact ring 14 ... .... Knurl 15 ... Female thread 2 ... Container body 21 ... Spout 22 ... Male Screw part 221 ... notch 222 ... notch width 3 ... movable protrusion
30... Disc-shaped movable protrusion 31... Junction point 311... Central hinge 312. ... Side hinge 314 ..... Disc spring 315 ..... Upper hinge 316 ..... Lower hinge 317 ..... Disc spring movable protrusion 32 .. ··········································································
4 ... cavity 41 ... movable side mold 410 ... core 411 ... rotary core 412 ... · Stopper 413 ·················································································・ ・ ・ ・ ・ Holddown piece 423 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Slide in the front-rear direction

Claims (4)

In a container consisting of a container body and a cap that can be opened and closed by screwing,
Has a notch in the container body thread,
A container with a locking function, characterized in that a movable protrusion that can be engaged and disengaged in the notch is formed integrally with the cap.   2. The container with a lock function according to claim 1, wherein the notch is machined into a threaded portion in the vicinity of the mouth end. The movable protrusion is a disk-shaped movable protrusion, and between the disk-shaped movable protrusion and the top of the cap,
The side shape is a truncated cone or a polygonal frustum, and the upper and lower sides are linear hinge portions, formed from a disc spring whose cone surface is inverted,
The container with a lock function according to claim 1 or 2, wherein the protrusion of the disk-shaped movable protrusion can be inserted into or extracted from the threaded portion by reversing the disc spring. The movable protrusion formed on the top of the cap
It is a disc spring movable projection that is formed from a disc spring with a conical surface or a polygonal frustum whose upper side is a linear hinge and the cone surface is inverted, and a projection is provided on the lower surface of the disc spring.
The container with a lock function according to claim 1 or 2, wherein the projection of the disc spring movable projection can be inserted into or extracted from the threaded portion by reversing the disc spring.

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