JP3222400B2 - Method of molding substantially cylindrical molded product, method of molding resin cylinder, manual trigger type dispenser and its cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a substantially cylindrical molded product having a lateral hole in a side wall, and more particularly to a method of molding a resin cylinder having a negative pressure prevention hole as a lateral hole in a side wall.
The present invention relates to a manual trigger type dispenser having a cylinder formed by this, and further relates to the cylinder.

[0002]

2. Description of the Related Art Due to the environmental problem of destruction of the ozone layer by chlorofluorocarbon gas, for example, a manual trigger type dispenser which pressurizes and discharges a liquid by reciprocating a piston interlocking with a trigger swing without using chlorofluorocarbon gas has recently been developed. , Has received particular attention.

[0003] As disclosed in Japanese Patent Application Laid-Open No. 08-224509, this type of dispenser is formed, for example, with a trigger that can be pulled (swinged) freely against the biasing force of a return spring. The piston that can reciprocate is connected to the trigger so as to be interlocked. Then, the liquid in the container is sucked into the cylinder and pressurized by the reciprocation of the piston in the cylinder accompanying the swing of the trigger, and the pressurized liquid is caused to flow out of the orifice (outlet) at the nozzle tip. , This dispenser is configured.

[0004] A cylinder provided in this type of dispenser is usually formed as a substantially cylindrical molded product having a bottom and an open end. Further, in such a cylinder, a negative pressure prevention hole for preventing negative pressure inside the container due to suction of liquid from the container is formed as a lateral hole in the side wall. The negative pressure prevention hole of the cylinder is provided so as to be able to communicate with the inside of the container, and can be opened to the outside air through the open end of the cylinder by sliding of the piston in the cylinder in the pressurizing direction.

[0005]

By the way, in a substantially cylindrical molded product such as the above-mentioned cylinder, the slide core is removably inserted into a predetermined mold and is projected by a slide core.
The hollow interior is defined and molded. Also,
For example, a lateral hole in the side wall such as a negative pressure prevention hole of a cylinder may
It is defined and formed by the close contact of fixed cores (cores for horizontal holes, cores for negative pressure prevention holes) protruding into the mold.

[0006] After molding a substantially cylindrical molded product such as a cylinder, the slide core is first withdrawn from the mold and pulled out of the molded product, and the molded product is separated by the subsequent mold separation. Removed from the mold.

Here, as described above, in the molding of a substantially cylindrical molded product having a lateral hole in a side wall, such as a cylinder, a lateral hole core (a negative pressure prevention hole core) is used in the molding process. Each time, the slide core is brought into close contact with a specific portion on the peripheral surface of the slide core, and the slide core moves in the retreating direction from the close contact state of the lateral hole core. Occurs on the peripheral surface (surface) of the slide core.

[0008] Such rubbing by the core for the horizontal hole in the close contact state easily causes damage to the peripheral surface of the slide core. The damage to the peripheral surface of the slide core damages the inner peripheral surface of the substantially cylindrical molded product that comes in contact with the retreat of the slide core, so that there is a possibility that the quality of the molded product is degraded. In particular, in the cylinder, the unevenness due to the scratch on the inner peripheral surface is likely to cause a gap between the seal piece of the piston slidingly contacting the inner peripheral surface.
There is a possibility that the airtightness in the cylinder may be reduced.

A configuration for preventing a decrease in airtightness in a cylinder is disclosed in, for example, Japanese Patent Application Laid-Open No. 08-266964. In this configuration, the inner peripheral surface of the cylinder has a stepped shape via a tapered portion. The slide core can be retracted without causing the damaged portion caused by the close contact and rubbing of the core to closely contact the inner peripheral surface of the large diameter portion of the cylinder. Therefore, damage to the inner peripheral surface of the large-diameter portion of the cylinder due to the retreat of the slide core can be prevented.

However, in this known configuration, the inside diameter of the bottom side of the cylinder separated and defined via the tapered portion is made smaller than the inside diameter of the open end side. The bottom side of this cylinder is a part that sucks up liquid and pressurizes it under sliding of the piston, and that directly affects the outflow of liquid in one stroke of the trigger, that is, one stroke of the piston. Therefore, it is unavoidable that the outflow of liquid is reduced when the outer diameter and the effective length of the cylinder are the same, which is due to the reduction in the inner diameter of the cylinder, although partially.

Further, in this known configuration, since the anti-negative pressure hole is provided only in the small diameter portion of the inner diameter of the cylinder, the small diameter portion of the slide core corresponding to the small diameter portion of the cylinder does not allow the slide core to retreat. It is highly likely that the core will rub against the core for the horizontal hole. In other words, when the slide core retreats, the damaged portion does not contact the inner peripheral surface of the large-diameter portion of the cylinder, but the small-diameter portion of the slide core may be damaged by rubbing with the core for the horizontal hole. However, the damage on the inner peripheral surface of the small diameter portion of the cylinder due to the damaged portion cannot be avoided.

By the way, the dispenser for discharging the liquid in the container is usually delivered to a detergent maker or the like as an assembled product, and is attached to the mouth of the container filled with the liquid such as the detergent at the delivery destination. Here, for example, a quality inspection for confirming the presence or absence of liquid leakage due to the pressure (external pressure) at the time of compressing the container after the dispenser is mounted under a specific pressure from the outside is performed in production. As one type of inspection, it is performed by a detergent maker or the like.

In this case, since the negative pressure prevention hole formed as a lateral hole in the side wall of the cylinder is communicated with the inside of the container, the liquid is pressurized in the container due to the compression of the container.
The liquid in the container flows out of the negative pressure prevention hole into the cylinder. However, in general, since the negative pressure prevention hole is located between the pair of seal pieces of the piston to close the negative pressure prevention hole against the outside air, the liquid flows to the outside of the cylinder in a normal state. The outflow is prevented by a seal piece located on the open end side of the cylinder.

However, Japanese Patent Application Laid-Open No. 08-224509,
In particular, as shown in FIG. 3 of the publication, a pair of seal pieces of a known piston are usually formed into a skirt shape which can slide on the inner peripheral surface of a cylinder under its elasticity. Since the directions are all outward, if the pressure accompanying the outflow of liquid between the pair of seal pieces becomes excessive, this pressure causes the seal pieces on the open end side of the cylinder to elastically deform inward in the radial direction. However, there is a possibility that the liquid leaks out of the cylinder from a gap between the seal piece and the inner peripheral surface of the cylinder that is generated with this.

Here, US Pat. No. 4,747,523 discloses a structure in which both of a pair of seal pieces of a piston are expanded toward the bottom of the cylinder. In this known configuration, the inner peripheral surface of the cylinder has a stepped shape in which the inside diameter of the bottom side of the cylinder is small and the inside diameter of the open end side is large, and a pair of seal pieces of the piston are provided with the small diameter. The outer diameter is formed in accordance with the part and the large diameter part.

According to such a shape of the seal piece, the seal piece located on the side of the opening end of the cylinder expands under the elastic deformation caused by the pressure acting between the pair of seal pieces, thereby causing the inside of the cylinder to expand. It is more firmly adhered to the peripheral surface. Therefore, even if the liquid flows from the negative pressure prevention hole to between the pair of seal pieces of the piston, leakage of the liquid to the outside of the cylinder is prevented.

However, also in this configuration, since the inner diameter of the bottom side of the cylinder is small, the outflow of the liquid can be reduced when the outer shape and effective length of the cylinder are the same for one stroke of the piston. Is inevitable.

According to the present invention, without damaging the inner peripheral surface,
It is an object of the present invention to provide a method of molding a substantially cylindrical molded product and a method of molding a resin cylinder that enable molding of a substantially cylindrical molded product having a lateral hole in a side wall such as a cylinder.

Further, the present invention provides a manual trigger type dispenser and a cylinder thereof, which can maintain a high airtightness in a cylinder having a negative pressure prevention hole as a lateral hole in a side wall without reducing the inner diameter of the cylinder. It is another object of the present invention.

[0020]

In order to achieve this object, according to the method for forming a substantially cylindrical molded product of the present invention, the slide core has a small-diameter end on the entering side and a large-diameter end on the retreating side. The tip of the core for a horizontal hole is brought into close contact with any of the at least partial slopes of the peripheral surface of the slide core except for the contact positions with the small-diameter end and the large-diameter end. Then, after the separation of the contact portion of the slope from the tip of the core for the horizontal hole accompanying the movement of the slide core in the retreating direction,
The slide core is retracted from the mold without contacting the side hole core.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1A, 1B and 2, in the manual trigger type dispenser 10 according to the present invention, a negative pressure prevention hole communicating with the inside of the container 14 is formed in the side wall of the cylinder 12. Numeral 16 is formed as a lateral hole, and the opening of the negative pressure prevention hole against the outside air caused by the sliding of the piston 18 in the pressurizing direction in the cylinder can prevent negative pressure in the container.

As shown in FIG. 2, the dispenser 10
A trigger 20 that can be pulled (oscillated) around a pivot point 20a serving as a fulcrum against the biasing force of a return spring (not shown).
And a cylinder 12 communicating with a liquid inflow passage 22 and a piston 18 slidable in the cylinder in conjunction with a trigger.

The dispenser 10 is formed to be attachable to the mouth 14a of the container 14 by the bottle cap 24, and reciprocates the piston 18 inside the cylinder 12 in conjunction with the swing of the trigger 20. Then, the liquid in the container is sucked up from the suction tube 26 and pressurized, and the pressurized liquid is caused to flow out of the orifice of the nozzle cap 28 connected to the outflow path.

The basic internal structure and operation principle of the dispenser 10 are the same as those of the known ones, and the basic structure itself is not the purpose of the present invention, and will not be described in detail here. As this kind of dispenser 10,
For example, the configuration disclosed in Japanese Patent Application Laid-Open No. 08-224509, particularly FIG.

The main components of the dispenser 10, such as the cylinder 12, the piston 18, the trigger 20, and the like, are usually each molded as a resin molded product formed by injection molding of a plastic material.

As can be seen from FIG. 3 in addition to FIG.
The cylinder 12 in such a dispenser 10 is molded as a substantially cylindrical molded product having a substantially uniform inner diameter. Here, similarly to the configuration disclosed in FIG. 3 of the above-mentioned Japanese Patent Application Laid-Open No. 08-224509, as shown in FIGS. 2 and 3, the cylinder 12 has a vertical cylindrical portion 30 defining a liquid inflow passage 22. A horizontal cylindrical portion 34 integrally defining a substantially horizontal outflow path (not shown) communicating with the inflow path, is formed as a substantially cylindrical body extending in the horizontal direction, and is formed on the bottom 12a with respect to the open end. The hollow interior communicates with the inflow channel via the hole 36.

As shown in FIG. 2, a valve housing 38 is attached to the lower end of the vertical cylindrical portion 30 of the cylinder by fitting or the like, and the valve housing 38 is connected to the valve housing via a suction tube 26 connected to an upper end 26a. The liquid inside the container 14 can flow into the inflow passage 22 of the cylinder. Also,
The valve housing 38 has a ventilation hole 40 that can communicate with the inside of the container 14 when the dispenser 10 is attached to the container opening 14a.
By connecting the ventilation hole to the negative pressure prevention hole 16 formed as a lateral hole in the side wall of the cylinder 12, the outside air into the container through the ventilation hole and the negative pressure prevention hole is formed. Inflow is possible.

The sliding of the piston 18 in the cylinder axis direction inside the cylinder 12 causes the liquid to be sucked up from the inflow passage 22 through the flow hole 36,
Pressurization is possible.

As can be seen from FIG. 3 in addition to FIG.
The piston 18 slides a pair of seal pieces 42-1 and 42-2 which can slide on the inner peripheral surface of the cylinder 12 under its elasticity in the sliding direction with respect to the cylinder, that is, the bottom side of the cylinder (right side in the figure). ) And at a position separated from the opening end side (left side in the figure). Such a piston 18 is provided, for example, with a receiving portion on the rear surface of the trigger corresponding to a substantially spherical connecting piece 18a provided at the tip (left end in the figure).
It is connected to the trigger 20 in an interlockable manner by loose fitting with the trigger 20b.

As shown in FIGS. 1A and 1B, such a substantially cylindrical cylinder 12 is, for example, a mold 44 composed of a movable mold and a fixed mold, and a cylinder 44. By injecting the molten plastic material into the cavity 48 defined by the combination of the slide core 46 and the like for molding the hollow part, a resin molded article of a corresponding shape is formed.

For example, at the time of molding, first, the slide core 46 is arranged so as to enter a corresponding position inside the mold 44, and a gap between the inner surface of the mold and the peripheral surface (surface) of the slide core is formed. By injection of the molten plastic material into the cavity 48 defined as, a cylinder (substantially cylindrical molded product) 12 having a desired shape is formed. And the cylinder
After the molding of 12, the slide core 46 is retracted with respect to the mold 44, and eventually the molded cylinder 12, and after the slide core is extracted from the inside of the cylinder, the movable mold and the fixed mold of the mold are separated to form a cylinder. Is removed from the mold.

In the molding by the slide core 46, the bottom 12a of the cylinder is formed by the leading end in the direction of entry, and the open end of the cylinder is formed by the base in the exiting direction (FIG. 1). (B), FIG. 2).

As shown in FIGS. 1 (A), 1 (B) and 2, the cylinder 12 has a negative pressure preventing hole 16 provided on a side wall thereof as a penetrating horizontal hole. Core for molding the part on the corresponding part of the side wall (core for negative pressure prevention hole)
50 is projected into the cavity 48 from one of the movable mold and the fixed mold of the mold 44 so as to be able to closely contact, for example, the entire surface of the tip with the peripheral surface of the slide core 46 as a core for a lateral hole.

This negative pressure preventing hole core (lateral hole core) 50
Is repeatedly brought into close contact with a specific portion on the peripheral surface of the slide core 46 each time the cylinder 12 is formed. And cavity 48
After injection of molten plastic material into the core,
With the 50 kept in close contact, the slide core 46 is withdrawn.

Here, as can be clearly seen from FIG. 1B, in the present invention, the cylinder 12 is
46 is the small diameter end 52a on the side of the entry direction, that is, the bottom side (right side in the figure) of the cylinder, and the large diameter end 52b is the side on the exit side of the slide core, that is, the open end side of the cylinder (left side in the figure). Is formed on a part of the inner peripheral surface thereof. And, as a horizontal hole having an opening on the slope 52, the cylinder negative pressure prevention hole 16 is
Formed on the side wall.

The slope 52 of the inner peripheral surface of the cylinder 12
Is formed, for example, as a part of the concave portion 54 provided on the inner peripheral surface of the cylinder, from the bottom end of the concave portion corresponding to the large-diameter end 52b of the slope to the bottom side (right side in the figure) of the cylinder.

The concave portion 54 and the inclined surface 52 of such a cylinder are formed by a correspondingly shaped protrusion 56 provided on the peripheral surface of the slide core 46. The projecting portion 56 has a small-diameter end 58 extending from the projecting end to the side of the slide core 46 in the direction of entry, that is, to the bottom side of the cylinder 12.
a, a slope 58 having a large-diameter end 58b on the side in the exit direction, and a slope 52 on the inner circumferential surface of the cylinder formed by the slope 58.
Is formed.

That is, according to the present invention, the core 50 for the anti-negative pressure hole is provided on the slope 58 having the small diameter end 58a on the side of the slide core 48 in the direction of entry and the large diameter end 58b on the side of the exit of the slide core 48.
Negative pressure prevention hole on the side of cylinder 12
16 are molded.

The anti-negative pressure hole 16 is provided on the slope of the cylinder 12.
Since it is sufficient that the cylinder 52 is formed with an opening, the concave portion 54 and the slope 52 of the cylinder have an arc width not less than the diameter of the negative pressure prevention hole.
It can be specified in L1 (see Fig. 1 (A)).

Further, as shown in FIG.
16 is provided at any position on the inclined surface 52 of the cylinder 12 except for the contact position with the small-diameter end 52a and the large-diameter end 52b. In other words, the negative pressure preventing hole core 50 is disposed at a position excluding the contact position with the small-diameter end 58a and the large-diameter end 58b of the slope of the slide core 46, and at a position where the tip can be in close contact with the slope 58. You.

Further, the concave portion 54 of the cylinder extends from the bottom end corresponding to the large-diameter end 52b of the inclined surface 52 to the open end side (left side in the figure) of the cylinder, for example, with the bottom side at the same position as the bottom end. It has a slope 60 with a radial end and an open end side as a small diameter end 60a. Also, a slope 62 corresponding to the slope 60 serves as a part of the protrusion 56 of the slide core, and a large-diameter end 58 of the slope 58.
It is provided on the side in the retreating direction (left side in the figure) from the tip that matches b.

Here, the phantom line indicated by the dashed line in FIGS. 1 (A) and 1 (B)
64, the inner peripheral surface of the cylinder 12 and the slide core 46
The flat surfaces of the peripheral surfaces of the cylinders and the slide cores will be clarified by using the flat surfaces. In the method of forming the cylinder 12 according to the present invention, the side of the slide core 46 in the approaching direction is
a, the tip of the core 50 for the negative pressure prevention hole is brought into close contact with the partial slope 58 of the slide core peripheral surface having the large-diameter end 58b on the exit side, thereby forming the negative pressure prevention hole on the side wall of the cylinder 12.
Has 16 moldings.

Under such close contact of the tip of the negative pressure prevention hole core 50 with the slope 58, the movement of the slide core 46 in the retreating direction causes the slope 58 of the slide core to become the negative pressure prevention hole core. Is instantly separated from the tip of. Since the negative pressure prevention hole core 50 is provided at a position other than the contact position with the small-diameter end 58a of the slope, the tip of the negative pressure prevention hole core and the flat portion of the peripheral surface of the slide core 46 are formed. An appropriate gap can be secured between them. Therefore, after separation of the contact portion of the slope 58 from the negative pressure prevention hole core 50, the slide core 46
Can move in the retreating direction without bringing the flat portion of the peripheral surface into contact with the core for a negative pressure prevention hole.

That is, according to the molding method of the present invention, the contact point of the core 50 for the anti-negative-pressure hole is changed to the slope 58 of the slide core.
Of the slide core
At the time of retreat of 46, since the core for the negative pressure prevention hole does not contact the flat surface portion of the peripheral surface of the slide core, damage to the slide core peripheral surface due to friction with the tip of the core for the negative pressure prevention hole may occur. Can be reliably prevented.

By preventing damage to the peripheral surface of the slide core 46, scratches due to the damage are not transferred to the inner peripheral surface of the cylinder 12 as unnecessary irregularities, and the molding accuracy of the cylinder is reliably improved. improves.

Here, in the molding method of the present invention,
A projection 56 is provided on the peripheral surface of the slide core 46, and a recess 54 on the inner peripheral surface of the cylinder is formed as a form in which the projection is fitted. However, the protrusion 56 on the peripheral surface of the slide core
The protrusion amount is small, the slide core has a slope 62 on the side in the retreating direction, and the protrusion is formed only partially in a predetermined arc width L1, and further, the cylinder is Considering that it is a substantially cylindrical molded product having one end opened, the protrusion does not hinder the slide core from retreating from the inside of the cylinder.

Note that, in the embodiment of the present invention,
Slope 6 on the side in the exit direction of protrusion 56 on the peripheral surface of slide core
2, and the corresponding slope 60 of the concave portion 54 on the inner peripheral surface of the cylinder is not limited to a linear slope, and a protruding end (large-diameter end) 58b and a small-diameter end 62a capable of guaranteeing retreat of the protruding portion from the concave portion.
A so-called curved surface is also included in the slope as long as it is on a line connecting between the bottom end 52b and the small diameter end 60a.

When the slide core 46 retreats, the projecting end (large diameter end) 58a of the projecting portion 54 on the slide core peripheral surface is set.
Move while contacting the slope 60 of the concave portion 54 on the inner peripheral surface of the cylinder and the inner peripheral surface on the opening end side from the concave portion. However, in the present invention, the tip of the core for negative pressure prevention hole 50 is in close contact with the slope 58 of the slide core peripheral surface at a position other than the contact position with the large-diameter end 58a. No damage or the like is caused on the protruding end of the protruding portion due to the close contact of the core for negative pressure prevention hole.

Accordingly, also from this point, it is possible to reliably prevent the inner peripheral surface of the cylinder 12 from being scratched when the slide core 46 retreats.

The cylinder 12 thus formed is
According to this, the transfer of the flaw to the inner peripheral surface in the molding process and the direct damage by the slide core 46 are reliably prevented, so that the airtightness in the cylinder is reliably achieved. Therefore, by providing the cylinder 12 in the manual trigger type dispenser 10, the certainty of sucking and pressurizing the liquid in the cylinder is improved, and thereby the product accuracy of the dispenser can be maintained higher.

Further, in the present invention, it is sufficient to form a partial slope 52 on the inner peripheral surface of the cylinder 12, so that the inner diameter of the cylinder can be made substantially uniform. That is, since the airtightness of the inner peripheral surface of the cylinder can be improved without providing a small-diameter portion in the inner diameter of the cylinder 12, according to the present invention, the outflow of liquid in one stroke of the piston 18 is reduced. Nothing.

In the embodiment of the present invention,
As the substantially cylindrical molded product, a resin cylinder 12 is illustrated, but a substantially cylindrical molded product having a lateral hole in a side wall is sufficient, and is not limited to the above-described cylinder, and is not limited to the cylinder described above. The present invention may be applied to a resin molded product. Also,
Although the resin cylinder is embodied as the cylinder 12 of the manual trigger type dispenser 10, it is not limited to the manual trigger type dispenser because a resin cylinder is sufficient. The present invention may be applied to a dispenser having an operation principle.

The contact position of the negative pressure prevention hole core 50 on the inclined surface 58 of the slide core peripheral surface and the position of the opening of the negative pressure prevention hole 16 on the inclined surface 52 of the inner peripheral surface of the cylinder are the small-diameter ends, Small diameter end excluding the position that contacts the large diameter end,
Needless to say, it suffices if the distance is between the large diameter ends, and the position is not limited to the illustrated position. Further, since it is sufficient if a lateral hole penetrating through the side wall of the cylinder 12 can be formed, the slide core 46 is required.
The direction in which the negative pressure prevention hole core 50 projects with respect to, and the direction in which the negative pressure prevention hole 16 is formed with respect to the side wall of the cylinder 12 are not limited to the direction orthogonal to the axis of the slide core as shown in the figure. It may be inclined with respect to the axis.

As shown in FIGS. 2 and 3, the piston 18 slidably disposed inside the cylinder 12 includes a bottom side (right side in the figure) of the cylinder and an open end side (left side in the figure). And a pair of seal pieces 42-1 and 42-2 spaced apart from each other are integrally formed on the outer peripheral surface thereof. The cylinder negative pressure prevention hole 16 is generally formed so as to be located between the pair of seal pieces 42-1 and 42-2 at the position where the piston 18 projects from the cylinder 12, and the initial position of the piston is set to the negative pressure. When the seal piece 42-2 on the open end side moves beyond the negative pressure prevention hole in the bottom direction due to the movement of the piston in the pressurizing direction due to the pulling of the trigger 20, the negative pressure prevention hole Are open to the outside air, which allows the outside air to flow into the container 14.

Here, in the present invention, the piston 18
Each of the pair of seal pieces 42-1 and 42-2 is formed in a skirt shape expanded toward the bottom of the cylinder 12. Since the inner peripheral surface of the cylinder 12 has a substantially uniform inner diameter with no steps from the bottom to the open end, the pair of sealing pieces (skirt-shaped sealing pieces) 42-1 and 4
2-2 are each formed to have substantially the same outer diameter that can slide on the inner peripheral surface of the cylinder under elasticity.

For example, as one type of production inspection by a detergent manufacturer or the like, a container 14 filled with a liquid such as a detergent is
When compressed by an appropriate external pressure in the initial position of the piston 18 shown in FIG. 2, the liquid inside the container is discharged into the cylinder 12 through the ventilation hole 40 and the negative pressure prevention hole 16 of the valve housing.
That is, it flows between the pair of seal pieces 42-1 and 42-2 of the piston. Then, due to the pressure caused by the inflow of the liquid, the seal pieces 42-1 and 42-2 of the piston tend to elastically deform according to their own shapes.

Here, in the present invention, the cylinder 12
The seal piece 42-2 of the piston located on the open end side (left side in the figure) of the piston is formed in a skirt shape that is expanded toward the bottom (right side in the figure), so that a pair of seal pieces 42- 1, 42-2
The pressure acting between the seal pieces 42-2
Is provided in the direction of expanding. In other words, the seal piece 42-2 on the open end side is more firmly attached to the inner peripheral surface of the cylinder 12 by expanding under elastic deformation due to the pressure acting between the pair of seal pieces 42-1 and 42-2. Negative pressure prevention hole
Even if the liquid flows from the pair 16 to between the pair of seal pieces 42-1 and 42-2 of the piston, the liquid is prevented from leaking out of the cylinder.

Accordingly, by forming both the pair of seal pieces 42-1 and 42-1 of the piston in the form of a skirt which is expanded toward the bottom of the cylinder 12, the airtightness inside the cylinder is improved. It becomes even more possible.

According to the present invention, the seal piece 42-1 located on the bottom side (right side in the figure) of the cylinder and the seal piece 42- located on the open end side (left side in the figure) of the cylinder. 2 is molded to almost the same outer diameter,
The arrangement of the piston 18 on the cylinder 12 on the inner peripheral surface having a substantially uniform inner diameter becomes easy. That is, since the inner peripheral surface of the cylinder 12 can be formed to have a substantially uniform inner diameter, airtightness of the cylinder 12 can be easily ensured without a decrease in the outflow amount of liquid per one stroke of the piston 18.

Incidentally, due to the pressure of the liquid flowing between the pair of seal pieces 42-1 and 42-2, the seal piece 42-1 on the base side of the cylinder 12 is in contact with the inner peripheral surface of the cylinder due to its shape. Elastic deformation occurs such that there is a gap between them. However, as can be seen from FIG. 2, even if the liquid flows out from between the seal piece 42-1 on the base side and the inner peripheral surface of the cylinder 12, this liquid only flows out into the cylinder. It has nothing to do with leakage of liquid outside the cylinder.

The embodiments of the present invention described above are intended to explain the present invention, and do not limit the present invention in any way. Modifications, alterations, and the like within the technical scope of the present invention may also be made. It goes without saying that all are included in the present invention.

[0063]

As described above, according to the molding method of the present invention, when the slide core retreats, the lateral hole core does not come into contact with the flat surface portion of the slide core peripheral surface. Damage to the peripheral surface of the slide core due to friction with the tip of the slide core can be reliably prevented. By preventing damage to the peripheral surface of the slide core, scratches due to the damage are not transferred to the inner peripheral surface of the cylinder as unnecessary irregularities, and the molding accuracy of the cylinder is reliably improved.

Also, when the slide core exits,
Because the protruding end of the slide core peripheral surface that does not contact the side hole core moves while contacting the cylinder inner peripheral surface,
For example, even if a damage or the like due to the close contact occurs in the close contact portion of the slope of the slide core, the damaged portion is reliably separated from the inner peripheral surface of the cylinder. Therefore, also from this point, it is possible to reliably prevent the inner peripheral surface of the cylinder from being damaged when the slide core is withdrawn.

According to the resin cylinder molded as described above, the transfer of the flaw to the inner peripheral surface in the molding process and the direct damage by the slide core are reliably prevented. Airtightness in the cylinder is ensured. Therefore, by providing this cylinder in the manual trigger type dispenser, the certainty of sucking and pressurizing the liquid in the cylinder is improved, and thereby the product accuracy of the dispenser can be maintained higher.

In the present invention, it is sufficient to form a partial slope on the inner peripheral surface of the cylinder, so that the inner diameter of the cylinder can be made substantially uniform. In other words, the airtightness of the inner peripheral surface of the cylinder can be improved without providing a small-diameter portion in the inner diameter of the cylinder. Therefore, according to the present invention, the outflow of liquid in one stroke of the piston may be reduced. Absent.

Further, according to the present invention, the pair of seal pieces of the piston located on the bottom side and the open end side of the cylinder are formed in a skirt shape which is expanded on the bottom side of the cylinder. Leakage of liquid through the cylinder can be reliably prevented, and the airtightness inside the cylinder is further improved.

According to the present invention, since the pair of seal pieces of the piston are formed to have substantially the same outer diameter, it is easy to dispose the piston on the cylinder on the inner peripheral surface having a substantially uniform inner diameter. It becomes possible. Therefore, the inner peripheral surface of the cylinder can be formed to have a substantially uniform inner diameter, and airtightness of the cylinder can be easily ensured without a decrease in the outflow of liquid per one stroke of the piston.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a cylinder of a manual trigger type dispenser according to the present invention in a direction orthogonal to an axis at a portion including a negative pressure prevention hole and in a direction along the axis.

FIG. 2 is a schematic side view of the manual trigger type dispenser, partially broken.

FIG. 3 is a perspective view of a cylinder and a piston.

[Explanation of symbols]

 10 Manual trigger type dispenser 12 Cylinder (substantially cylindrical molded product, resin cylinder) 14 Container 16 Negative pressure prevention hole (lateral hole) 18 Piston 20 Trigger 42-1, 42-2 A pair of piston seal pieces 44 Mold 46 Slide core 48 Cavity 50 Negative pressure prevention hole core (lateral hole core) 52 Slope of cylinder inner peripheral surface 54 Recess of cylinder inner peripheral surface 56 Projection of slide core peripheral surface 58 Slope of slide core peripheral surface

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 33/76 B05B 11/00 102

Claims (5)

(57) [Claims] 1. A substantially cylindrical mold having a lateral hole in a side wall by closely adhering a tip of a lateral hole core to a specific portion of a peripheral surface of a slide core that defines the inside by entering a predetermined mold. In the method of forming a substantially cylindrical molded product, in which the slide core is extracted from the inside of the molded product by molding and retreating after molding, the slide core has a small-diameter end on the ingress direction side and a large-diameter end on the retreat direction side. The tip of the horizontal hole core is brought into close contact with any of the at least partial slopes of the core peripheral surface except for the contact positions with the small-diameter end and the large-diameter end, and the slide core is moved in the retreating direction. Molding of a substantially cylindrical molded product characterized in that the slide core is withdrawn from the mold without contact with the horizontal hole core after the separation of the slope contact point from the tip of the horizontal hole core due to movement One . 2. A tip of a negative pressure prevention hole core is brought into close contact with a specific portion of a peripheral surface of a substantially cylindrical slide core that defines a substantially uniform inner diameter by entering into a predetermined mold to form a lateral hole. Forming a substantially cylindrical resin cylinder having a negative pressure prevention hole on the side wall thereof, and removing the slide core from the inside of the cylinder by retreating after molding, wherein a protrusion having a predetermined arc width is provided. Except for the small-diameter end and the large-diameter end, the contact positions with the small-diameter end and the large-diameter end of the partial slope of the slide core peripheral surface formed by the slide core having the small diameter end on the entry direction side and the large diameter end on the retraction direction side formed by Attach the tip of the negative pressure prevention hole core to any position, and prevent negative pressure after separating the contact point of the slope from the tip of the negative pressure prevention hole core as the slide core moves in the retreating direction. Hole Without contacting the core, the molding method of the resin-made cylinder was characterized by Eject the slide core. 3. A pair of seal pieces spaced apart from a bottom side and an open end side of a cylinder formed as a substantially cylindrical molded product having a bottom are slidably contacted with an inner peripheral surface, and a piston is disposed inside the cylinder. The liquid in the container is sucked up into the cylinder and pressurized by the reciprocating motion of the piston in conjunction with the swing, and the pressurized liquid flows out of the orifice at the tip of the nozzle that is continuous with the outflow passage, and the outside air flows into the container. In a manual trigger type dispenser molded on the side wall of the cylinder, a negative pressure prevention hole that ensures inflow can be opened to the outside air as the piston slides in the pressurizing direction. A slope having a small-diameter end in the bottom direction and a large-diameter end in the opening end direction to the bottom is partially formed on the inner peripheral surface of the cylinder having a substantially uniform inner diameter. Beauty as transverse bore having an opening in any position except the contact position between each of the large diameter end, a manual trigger type dispenser the vacuum prevention hole is equal to or molded into the side wall of the cylinder. 4. A pair of seal pieces separated from a bottom side and an open end side of a cylinder formed as a substantially cylindrical molded product having a bottom are slidably contacted with an inner peripheral surface, and a piston is disposed inside the cylinder. The liquid in the container is sucked up into the cylinder and pressurized by the reciprocating motion of the piston in conjunction with the swing, and the pressurized liquid flows out of the orifice at the tip of the nozzle that is continuous with the outflow passage, and the outside air flows into the container. In a manual trigger type dispenser molded on the side wall of the cylinder, a negative pressure prevention hole that ensures inflow can be opened to the outside air as the piston slides in the pressurizing direction. A slope having a small-diameter end in the bottom direction and a large-diameter end in the opening end direction to the bottom is partially formed on the inner peripheral surface of the cylinder having a substantially uniform inner diameter. The negative pressure prevention hole is formed in the side wall of the cylinder as a horizontal hole having an opening at any position except the contact position with each of the large diameter end and the cylinder, and is separated from the bottom side of the cylinder and the opening end side. Both of the pair of seal pieces of the piston provided are formed into a skirt shape having substantially the same outer diameter expanded in the bottom direction of the cylinder, which can slide on the inner peripheral surface of the cylinder under its elasticity. A manual trigger type dispenser characterized by being molded respectively. 5. A piston formed as a substantially cylindrical molded product having a substantially uniform inner diameter and having a bottom, and a piston interlocking with the swing of the trigger is disposed slidably in the axial direction along the inner peripheral surface thereof. At the same time, in a cylinder of a manual trigger type dispenser which can ensure the inflow of outside air into the container through a negative pressure prevention hole formed as a side hole in the side wall, a concave portion having a predetermined arc width on the inner peripheral surface. A slope having a small-diameter end in the bottom direction and a large-diameter end in the opening end direction with respect to the bottom is partially formed on the inner peripheral surface, and any of the slopes except for a contact position with each of the small-diameter end and the large-diameter end. A cylinder for a manual trigger type dispenser, wherein the negative pressure prevention hole is formed in a side wall as a lateral hole having an opening at a position.