Discharge pump

Abstract

A discharge pump (2) comprises: an attachment cap (5) that is attached to a mouth part (3a) of a container (3); a cylinder member (6) that is held by the attachment cap (5) and has a sliding-receiving surface (6b1); a piston (7) that slides in the vertical direction on the sliding-receiving surface (6b1); a pump chamber (8) that is partitioned by the cylinder member (6) and the piston (7); and a lifting member (9) that has a discharge port (9a1), the lifting member (9) rising and falling relative to the cylinder member (6) in tandem with the piston (7), thereby sending contents (4) from the interior of the container (3) to the discharge port (9a1) via the pump chamber (8) and discharging the contents (4). The cylinder member (6) has an upper cylinder member (6a) that is held by the attachment cap (5), and a lower cylinder member (6b) that is attached to and held by the upper cylinder member (6a) and has the sliding-receiving surface (6b1).

Description

Discharge pump

[0001] The present invention relates to a discharge pump.

[0002] A discharge pump is known that includes an attachment cap that is attached to the mouth of a container, a cylinder member that is held by the attachment cap and has a sliding surface, a piston that slides up and down on the sliding surface, a pump chamber defined by the cylinder member and the piston, and a lifting member that has a discharge port and moves up and down relative to the cylinder member together with the piston to send and discharge the contents from within the container through the pump chamber to the discharge port (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-117227

[0004] In order to improve the sliding properties of the piston, if the cylinder member is formed from a slippery material, formed by adding a lubricant to the material, or formed and then completely coated with a lubricant, the fitting parts with surrounding parts such as the mounting cap may also become slippery, which may result in insufficient fitting force.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a discharge pump that can achieve both the sliding properties of the piston and the fitting force of the cylinder member relative to the surrounding members.

[0006] One aspect of the present invention is as follows.

[0007] [1] A discharge pump comprising: an attachment cap attached to the mouth of a container; a cylinder member held by the attachment cap and having a sliding surface; a piston that slides up and down on the sliding surface; a pump chamber defined by the cylinder member and the piston; and an elevating member that has a discharge port and moves up and down relative to the cylinder member together with the piston to send and discharge the contents from within the container to the discharge port via the pump chamber, wherein the cylinder member comprises an upper cylinder member held by the attachment cap, and a lower cylinder member that is attached to and held by the upper cylinder member and has the sliding surface.

[0008] [2] The discharge pump according to [1], wherein the upper cylinder member has a retaining portion that prevents the lifting member from slipping out upward from the lower cylinder member.

[0009] [3] The discharge pump according to [1] or [2], wherein the lower cylinder member has a lower cylinder peripheral wall having the sliding surface, the lower cylinder peripheral wall having a fitting hole penetrating the lower cylinder peripheral wall above the sliding surface in the radial direction, and a guide groove extending from the upper end of the lower cylinder peripheral wall along the inner peripheral surface of the lower cylinder peripheral wall to just before the fitting hole, the upper cylinder member has an upper cylinder peripheral wall that contacts the inner peripheral surface of the lower cylinder peripheral wall above the sliding surface, the upper cylinder peripheral wall having a fitting protrusion that protrudes radially outward, the fitting protrusion passing downward through the guide groove and fitting into the fitting hole.

[0010] [4] A discharge pump according to any one of [1] to [3], wherein the mounting cap has a mounting tube attached to the outer peripheral surface of the mouth portion and a top wall extending radially inward from the upper end of the mounting tube, the upper cylinder member has a flange portion sandwiched between the upper end surface of the mouth portion and the top wall, and the mounting tube of the mounting cap has a restricting protrusion that abuts against the outer peripheral edge portion of the flange portion to prevent the outer peripheral edge portion from slipping out downward from the upper end of the inner peripheral surface of the mounting tube.

[0011] [5] The discharge pump according to any one of [1] to [4], wherein the piston has a base end, a lower seal portion having a lower end inclined radially outward downward from the base end and sliding on a sliding surface, and an upper seal portion extending upward and abutting against the cylinder member at least at the top dead center of the elevating member, wherein the lower seal portion has a bend portion between the base end and the bottom end which is a transition position where the inclination angle changes discontinuously, and the bottom end below the bend portion has a larger angle of inclination radially outward downward than the base end above the bend portion, and wherein the radially inner surface of the lower seal portion is provided with a first recess that overlaps with the bend portion or is provided adjacent to and below the bend portion and is recessed radially outward.

[0012] [6] The discharge pump according to [5], which has one or more second recesses below the first recess.

[0013] [7] The discharge pump according to [5] or [6], wherein the upper end of the upper seal portion has a protrusion that protrudes radially inward, and at least at the top dead center of the lifting member, the protrusion abuts from the radially outer side against an abutting tubular portion that hangs down from the top of the cylinder member, radially inward of the sliding surface of the cylinder member.

[0014] According to the present invention, it is possible to provide a discharge pump that can achieve both the slidability of the piston and the fitting force of the cylinder member relative to the surrounding members.

[0015] 5 is a cross-sectional view showing a state before discharge of a discharge container according to a first embodiment of the present invention. FIG. 5 is a cross-sectional view showing a state during discharge of the discharge container shown in FIG. 1. (a) is a top view of a lower cylinder member shown in FIG. 1, and (b) is a partially sectional side view of the lower cylinder member shown in (a). (a) is a partially sectional side view of an upper cylinder member shown in FIG. 1, and (b) is a bottom view of the upper cylinder member shown in (a). FIG. 5 is a cross-sectional view showing a state before discharge of a discharge container according to a second embodiment of the present invention. FIG. 5 is an enlarged view of a piston portion in FIG. 5. FIG. 5 is a cross-sectional view showing a state during discharge of the discharge container shown in FIG. 5. FIG. 5 is an enlarged view showing a first modified example of the piston in FIG. 5. FIG. 5 is an enlarged view showing a second modified example of the piston in FIG. 5.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] 1 and 2, in the first embodiment of the present invention, a discharge container 1 has a discharge pump 2 and a container 3. The container 3 has a mouth 3a, a body 3b, and a bottom (not shown) connected in this order, and contains a content 4. The content 4 is not particularly limited, but in this embodiment it is a liquid such as lotion or shampoo.

[0018] The discharge pump 2 comprises an attachment cap 5 attached to the mouth 3a of the container 3, a cylinder member 6 held by the attachment cap 5 and having a sliding surface 6b1 on its inner circumferential surface centered on the central axis O, a piston 7 sliding up and down on the sliding surface 6b1, a pump chamber 8 defined below the piston 7 by the cylinder member 6 (lower cylinder member 6b) and the piston 7, and a lifting member 9 having a discharge port 9a1 and moving up and down (reciprocating up and down) with the piston 7 relative to the cylinder member 6 to send and discharge the contents 4 from within the container 3 through the pump chamber 8 to the discharge port 9a1, and the cylinder member 6 comprises an upper cylinder member 6a held by the attachment cap 5, and a lower cylinder member 6b attached to and held by the upper cylinder member 6a and having the sliding surface 6b1.

[0019] In this embodiment, the direction along the central axis O is referred to as the vertical direction, the direction from the bottom side of the container 3 toward the mouth 3a along the vertical direction is referred to as the upward direction, the opposite direction is referred to as the downward direction, the direction perpendicular to the central axis O is referred to as the radial direction, and the direction circumferentially around the central axis O is referred to as the circumferential direction.

[0020] The lifting member 9 has a push-down head 9a having a discharge port 9a1 and being pressed down, a stem portion 9b extending downward from the push-down head 9a and moving up and down together with the piston 7, an internal flow path 9c extending from the pump chamber 8 to the discharge port 9a1, and an opening / closing portion 9d that opens the internal flow path 9c when the lifting member 9 is lowered and closes the internal flow path 9c when the lifting member 9 is raised. Note that the discharge pump 2 is not limited to the push-down head type, and may be configured as, for example, a trigger type in which the piston 7 is moved by pulling a trigger.

[0021] In this embodiment, the stem portion 9b is cylindrical and centered on the central axis O, and is composed of a stem 9b1 attached to the press-down head 9a, and a piston guide 9b2 attached to the inner peripheral surface of the stem 9b1, and holds the piston 7 between the stem 9b1 and the piston guide 9b2 so that the piston 7 can be raised and lowered. The opening and closing portion 9d is formed by the piston 7 and the piston guide 9b2 at the upstream end of the internal flow path 9c, and opens when the piston guide 9b2 descends relative to the piston 7, and closes when the piston guide 9b2 ascends relative to the piston 7. Note that the opening and closing portion 9d is not limited to a configuration formed by the piston 7 and the piston guide 9b2.

[0022] The discharge pump 2 has a suction valve 10 that closes the upstream end of the pump chamber 8 when the lifting member 9 descends, and opens the upstream end of the pump chamber 8 by creating a negative pressure in the pump chamber 8 when the lifting member 9 ascends. In this embodiment, the suction valve 10 is configured by an elastic valve 10a that has a valve body support portion 10a1 held within the pump chamber 8 and an elastic valve body 10a2 that is connected to the valve body support portion 10a1 and can be raised and lowered by elastic deformation, but the present invention is not limited to this.

[0023] The discharge pump 2 has a spring portion 11 that urges the lifting member 9 upward, and by pressing the press head 9a against the urging force of the spring portion 11, the lifting member 9 is lowered and the contents 4 are sent from the pump chamber 8 to the discharge port 9a1 and discharged, while by releasing the pressing operation, the urging force of the spring portion 11 causes the lifting member 9 to rise and the contents 4 are sucked from the container 3 into the pump chamber 8.

[0024] The lower cylinder member 6b has an air vent 6b2 at the upper end of the sliding surface 6b1, and the discharge pump 2 has an outside air introduction path 12 that introduces outside air into the container 3 through the air vent 6b2 as the content 4 is discharged. The piston 7 is annular about the central axis O. The piston 7 also has a lower skirt portion (lower seal portion) 7a that expands in diameter downward and whose lower end slides on the sliding surface 6b1, and an upper skirt portion (upper seal portion) 7b that expands in diameter upward from the upper end of the lower skirt portion 7a and whose upper end slides on the sliding surface 6b1. The lower skirt portion 7a and the upper skirt portion 7b cover the air vent 6b2 when the elevating member 9 is at its highest position, thereby preventing the content 4 from leaking through the air vent 6b2. When the lifting member 9 descends from its highest position, the upper skirt portion 7b passes downward through the vent hole 6b2, allowing outside air to be introduced through the vent hole 6b2. Note that the lower cylinder member 6b may be configured not to have the vent hole 6b2, and a fitting hole 6b5 (described later) may be used to introduce outside air instead of the vent hole 6b2, as in a second embodiment (described later).

[0025] The mounting cap 5 includes a mounting tube 5a threadedly attached to the outer circumferential surface of the mouth portion 3a, an annular top wall 5b extending radially inward from the upper end of the mounting tube 5a, and a guide tube 5c extending upward from the inner circumferential edge of the top wall 5b and guiding the press-down head 9a as it ascends and descends. The upper cylinder member 6a includes a flange portion 6a1 sandwiched between the upper end surface of the mouth portion 3a and the top wall 5b. The mounting tube 5a of the mounting cap 5 includes a restricting protrusion 5a1 that abuts against the outer circumferential edge of the flange portion 6a1 to prevent it from slipping downward from the upper end of the inner circumferential surface of the mounting tube 5a. The restricting protrusion 5a1 extends continuously or intermittently in the circumferential direction. A gasket 13 is provided on the underside of the flange portion 6a1 and is sandwiched between the flange portion 6a1 and the upper end surface of the mouth portion 3a.

[0026] As shown in Figures 1 and 3, the lower cylinder member 6b has a sliding surface 6b1 and a lower cylinder peripheral wall 6b3 centered on the central axis O. The lower cylinder bottom 6b4 is connected to the lower end of the lower cylinder peripheral wall 6b3. The lower cylinder bottom 6b4 has a through-hole 6b7 through which the contents 4 pass. The valve body support portion 10a1 is supported at the lower end of the lower cylinder peripheral wall 6b3. The lower cylinder peripheral wall 6b3 has a fitting hole 6b5 that penetrates the lower cylinder peripheral wall 6b3 radially above the sliding surface 6b1, and a guide groove 6b6 that extends from the upper end of the lower cylinder peripheral wall 6b3 along the inner circumferential surface of the lower cylinder peripheral wall 6b3 to just before the fitting hole 6b5. The guide groove 6b6 is formed as a recess that does not penetrate the lower cylinder peripheral wall 6b3 radially and opens upward. The lower end of the guide groove 6b6 forms a guide surface whose radial depth gradually decreases downward. The fitting hole 6b5 and the guide groove 6b6 are provided at the same circumferential position and with the same width.

[0027] As shown in Figures 1 and 4, the upper cylinder member 6a has an upper cylinder peripheral wall 6a2 extending downward from the inner peripheral edge of the flange portion 6a1. The upper cylinder peripheral wall 6a2 is inserted into the lower cylinder peripheral wall 6b3 of the lower cylinder member 6b and contacts the inner peripheral surface of the lower cylinder peripheral wall 6b3 above the sliding surface 6b1. The upper cylinder peripheral wall 6a2 has a fitting protrusion 6a3 protruding radially outward. The fitting protrusion 6a3 passes downward through the guide groove 6b6 and fits into the fitting hole 6b5, restricting the upward movement of the upper cylinder member 6a relative to the lower cylinder member 6b. The lower surface of the fitting protrusion 6a3 is inclined radially outward from bottom to top, and the upper surface extends horizontally. The upper cylinder peripheral wall 6a2 also has a stopper surface 6a4 that abuts against the lower cylinder peripheral wall 6b3 to restrict the downward movement of the upper cylinder member 6a relative to the lower cylinder member 6b. In this embodiment, the stopper surface 6a4 is provided in a stepped shape on the outer peripheral surface of the upper cylinder peripheral wall 6a2 and abuts against the upper end surface of the lower cylinder peripheral wall 6b3, but is not limited to this. The upper cylinder member 6a and the lower cylinder member 6b are fitted together by inserting the fitting protrusion 6a3 into the guide groove 6b6, pushing the upper cylinder member 6a toward the lower cylinder member 6b, and abutting the stopper surface 6a4 of the upper cylinder member 6a against the upper end surface of the lower cylinder peripheral wall 6b3, whereby the fitting protrusion 6a3 enters and engages with the fitting hole 6b5.

[0028] In this embodiment, four sets of fitting holes 6b5, guide grooves 6b6, and fitting protrusions 6a3 are provided at equal intervals in the circumferential direction. However, the number of sets of fitting holes 6b5, guide grooves 6b6, and fitting protrusions 6a3 provided in the cylinder member 6 is not limited to this. The upper cylinder member 6a and the lower cylinder member 6b are each formed by injection molding of a resin material.

[0029] The upper cylinder member 6a has a retaining portion (protective portion) 6a5 that prevents the lifting member 9 from slipping out upward from the lower cylinder member 6b. In this embodiment, the retaining portion 6a5 is formed by the lower end of the upper cylinder peripheral wall 6a2, and prevents the lifting member 9 from slipping out upward from the lower cylinder member 6b by abutting against the upper end of the upper skirt portion 7b of the piston 7. Note that the retaining portion 6a5 is not limited to this, and may be configured to prevent the lifting member 9 from slipping out upward from the lower cylinder member 6b by abutting against the stem portion 9b, for example.

[0030] The upper cylinder member 6a has a spring receiving portion 6a6 extending radially inward from the upper cylinder peripheral wall 6a2. The spring receiving portion 6a6 is composed of an annular wall 6a7 extending radially inward and a cylindrical wall 6a8 extending upward from the inner peripheral edge of the annular wall 6a7. The lower end of a spring portion 11 is fitted between the cylindrical wall 6a8 and the upper cylinder peripheral wall 6a2. The spring portion 11 is an annular spring that surrounds the stem 9b1 in a top view and is a resin compression spring that expands and contracts in the vertical direction. The upper end of the spring portion 11 supports the press-down head 9a. The spring portion 11 is not limited to being made of resin and may be made of metal, for example.

[0031] The lower cylinder member 6b has higher lubricity than the upper cylinder member 6a in order to improve slidability on the sliding surface 6b1. Lubrication of the lower cylinder member 6b can be achieved by selecting a material with higher lubricity than the upper cylinder member 6a, molding the lower cylinder member 6b from a resin material to which a lubricant such as a metal salt of a higher fatty acid has been added (mixed), or applying a lubricant such as silicone after the lower cylinder member 6b is formed. Among these, adding a lubricant is preferable from the viewpoint of productivity. Note that, for example, when the lower cylinder member 6b and the upper cylinder member 6a are molded from the same resin material, it is preferable not to add or apply a lubricant to the upper cylinder member 6a.

[0032] According to this embodiment, the cylinder member 6 is composed of an upper cylinder member 6a that is held by fitting into the mounting cap 5, and a lower cylinder member 6b that has a sliding surface 6b1 and is more lubricious than the upper cylinder member 6a, so that it is possible to achieve both the sliding ability of the piston 7 on the sliding surface 6b1 and the fitting force of the upper cylinder member 6a into the mounting cap 5.

[0033] Next, a second embodiment of the present invention will be described.

[0034] 5 and 7 show a discharge container 1 in which a discharge implement (discharge pump) 2 according to the second embodiment is attached to a mouth 3a of a container 3. The container 3 has a mouth 3a, a body 3b, and a bottom (not shown) connected in this order from top to bottom, and contains a content 4. The content 4 is not particularly limited, but in this embodiment it is a liquid such as lotion or shampoo.

[0035] In the description of the second embodiment, the side where a lifting member 9 described later is located is referred to as the upper side (upper side in FIG. 5), and the side where a container 3 is disposed is referred to as the lower side (lower side in FIG. 5). Furthermore, the radially outward direction refers to the direction away from the central axis O along a straight line that passes through the central axis O of the discharge container 1 and is perpendicular to the central axis O, and the radially inward direction refers to the direction toward the central axis O along this straight line. Furthermore, the circumferential direction refers to the rotation direction around the central axis O. The side of the discharge tool 2 where a through hole 6b7 through which the contents 4 in the container 3 flow is provided is sometimes referred to as the upstream side, and the side where a discharge port 9a1 is provided is sometimes referred to as the downstream side.

[0036] The discharge tool 2 comprises an attachment cap 5 attached to the mouth 3a of the container 3, a cylinder member 6 held by the attachment cap 5 and having a sliding surface 6b1 on the inside, a piston 7 that slides up and down on the sliding surface 6b1, a pump chamber 8 defined below the piston 7 by the cylinder member 6 (lower cylinder member 6b) and the piston 7, and an elevating member 9 having a discharge port 9a1 and moving up and down (reciprocating up and down) with the piston 7 relative to the cylinder member 6 to send and discharge the contents 4 in the container 3 through the pump chamber 8 to the discharge port 9a1. The cylinder member 6 comprises an upper cylinder member 6a held by the attachment cap 5, and a lower cylinder member 6b attached to and held by the upper cylinder member 6a and having the sliding surface 6b1.

[0037] The lifting member 9 has a push-down head 9a having a discharge port 9a1 and being pressed down, a stem portion 9b extending downward from the push-down head 9a and moving up and down together with the piston 7, an internal flow path 9c extending from the pump chamber 8 to the discharge port 9a1, and an opening / closing portion 9d that opens the internal flow path 9c when the lifting member 9 descends and closes the internal flow path 9c when the lifting member 9 ascends. Note that the discharge tool 2 is not limited to a mode that uses the push-down head 9a, and may be configured so that the piston is moved by pulling a trigger, for example.

[0038] In this embodiment, the stem portion 9b has a cylindrical shape centered on the central axis O and includes a stem 9b1 attached to the press-down head 9a and a piston guide 9b2 attached to the inner circumferential surface of the stem 9b1. The piston 7 is held between the stem 9b1 and the piston guide 9b2 so that it can move up and down. The opening / closing portion 9d is formed at the upstream end of the internal flow path 9c by a lower contact portion 7d of the piston 7 and the piston guide 9b2. The opening / closing portion 9d opens when the piston guide 9b2 moves down relative to the piston 7, and closes when the piston guide 9b2 moves up relative to the piston 7. Note that the opening / closing portion 9d is not limited to being formed by the piston 7 and the piston guide 9b2.

[0039] The discharge tool 2 has a suction valve 10 that closes the upstream end of the pump chamber 8 when the lifting member 9 descends, and opens the upstream end of the pump chamber 8 by creating a negative pressure in the pump chamber 8 when the lifting member 9 ascends. In this embodiment, the suction valve 10 is configured by an elastic valve 10a that has a valve body support portion 10a1 held within the pump chamber 8 and an elastic valve body 10a2 supported on the valve body support portion 10a1 so as to be movable up and down by elastic deformation of an arm, but is not limited to this.

[0040] The discharge tool 2 has a spring portion 11 that urges the lifting member 9 upward, and by pressing the depression head 9a against the urging force of the spring portion 11, the lifting member 9 is lowered, sending the contents 4 in the pump chamber 8 to the discharge port 9a1 and discharging them. When the pressing operation is released, the lifting member 9 rises due to the urging force of the spring portion 11, and sucks the contents 4 from the container 3 into the pump chamber 8.

[0041] The lower cylinder member 6b has a fitting hole 6b5 at its upper part, and the dispenser 2 has an outside air introduction path 12 that introduces outside air into the container 3 through the fitting hole 6b5 as the content 4 is dispensed. The outside air introduction path 12 guides outside air into the container 3 through the gap between the stem 9b1 and the spring portion 11, the gap between the lower cylinder peripheral wall 6b3 and the upper cylinder peripheral wall 6a2, and the fitting hole 6b5 (see FIG. 7). The piston 7 is annular, centered on the central axis O. 6 , the piston 7 has a lower seal portion 7a having a base end portion 7a5 connected to a lower portion of the radially outer end of the central base portion 7c, a lower end portion 7a4 inclined radially outward downward from the base end portion 7a5 and sliding on the sliding surface 6b1, and an upper seal portion 7b extending upward from the central base portion 7c and abutting against the outer surface of the lower portion (abutment tubular portion 6a9) of the upper cylinder member 6a at least at the top dead center of the elevating member 9. The piston 7 also has a lower abutment portion 7d extending downward from the radially inner end of the central base portion 7c and an upper abutment portion 7e extending upward. That is, the central base portion 7c connects the lower seal portion 7a and the upper seal portion 7b at approximately the center in the vertical direction at its radially outer end, and connects the lower abutment portion 7d and the upper abutment portion 7e at approximately the center in the vertical direction at its radially inner end. The lower contact portion 7d forms an opening / closing portion 9d together with the piston guide 9b2. The upper contact portion 7e slidably contacts the radially inner surface of the lower portion of the stem 9b1.

[0042] The lower seal portion 7a has a lower end portion 7a4 with a larger inclination angle relative to the central axis O than a base end portion 7a5 directly below the central base portion 7c, and a first recess 7a1 recessed radially outward is provided on the radially inner surface of the lower seal portion 7a. Also, a second recess 7a2 recessed radially outward is provided below the first recess 7a1.

[0043] The lower seal portion 7a has a bent portion 7a3, which is a transition point where the inclination angle changes discontinuously. That is, in the example shown in FIG. 6 , the base end 7a5 (the range from the upper edge of the lower seal portion 7a to the bent portion) directly below the central base 7c of the lower seal portion 7a extends almost vertically downward, while the lower end 7a4, located below the bent portion 7a3 shown in the figure, has an increasingly radially outward inclination angle. The first recess 7a1 overlaps the bent portion 7a3 or is located adjacent to and below the bent portion 7a3. In the example shown in FIG. 6 , the upper end of the first recess 7a1 overlaps the bent portion 7a3, but the upper end of the first recess 7a1 may coincide with the lower end of the bent portion 7a3 or may be located below the bent portion 7a3. Furthermore, the upper end of the first recess 7a1 may extend upward beyond the bent portion 7a3. The corners of the inner surface of the bent portion 7a3 may be rounded. The base end portion 7a5 may also have a configuration that extends downward and radially outward.

[0044] The base end 7a5 of the lower seal portion 7a is a region above a bent portion 7a3 (described later) of the lower seal portion 7a extending downward from the central base 7c, and is adjacent to the bottom of the central base 7c. The bottom end 7a4 of the lower seal portion 7a is a region below the bent portion 7a3 (described later), and is the lower region of the lower seal portion 7a that contacts the sliding surface 6b1 in FIG. 6. Therefore, the inclination angle of the base end 7a5 is defined in the region above the bent portion 7a3 of the lower seal portion 7a. The inclination angle of the lower end 7a4 is defined in the region below the bent portion 7a3 of the lower seal portion 7a.

[0045] The base end 7a5 and the lower end 7a4 may each have a linear cross-sectional shape as shown in FIG. 6 , or may each have an arc-shaped cross-sectional shape. When the base end 7a5 and the lower end 7a4 are arc-shaped, the inclination angles of the base end 7a5 and the lower end 7a4 are defined as the average inclination angle above the bent portion 7a3 and the average inclination angle below the bent portion 7a3, respectively. The average inclination angle of the base end 7a5 is the angle of a line connecting the radial center of the upper edge of the base end 7a5 to the radial center of the lower edge. The average inclination angle of the lower end 7a4 is the angle of a line connecting the radial center of the upper edge of the lower end 7a4 to the radial center of the lower edge.

[0046] In this embodiment, a first recess 7a1 is provided that overlaps the bent portion 7a3 or is provided adjacent to and below the bent portion 7a3 and recesses radially outward. Furthermore, two second recesses 7a2 are provided below the first recess 7a1. In the example shown in FIG. 6 , the upper end of the first recess 7a1 overlaps the bent portion 7a3. This configuration increases the radially outward inclination angle below the bent portion 7a3, thereby enabling the lower end 7a4 (the tip of the lower end 7a4) of the lower seal portion 7a to slide more reliably against the sliding surface 6b1 of the cylinder member 6 for sealing. Furthermore, when the lifting member 9 is pressed down, the lower seal portion 7a is bent at the height positions of the first recess 7a1 and the second recess 7a2 so that the lower end 7a4 of the lower seal portion 7a is slightly displaced radially inward. Therefore, the frictional force between the lower seal portion 7a and the sliding surface 6b1 when the lifting member 9 is pressed down can be reduced.

[0047] Furthermore, when the piston 7 is provided with the first recess 7a1 and the second recess 7a2, shapes corresponding to the first recess 7a1 and the second recess 7a2 can be provided on the core (male mold) side when molding the piston 7 in a mold, making it possible to easily engage the molded piston 7 with the recesses and protrusions on the core side. With this configuration, when the mold is opened, the piston 7 can be engaged with the core side, making it easy to release from the cavity (female mold), and the molded piston 7 can be easily removed from the mold.

[0048] The second recess 7a2 may be provided in only one location below the first recess 7a1, or in three or more locations. As shown in FIG. 8 , the lower seal portion 7a may be configured with only one first recess 7a1 and no second recess 7a2. Even with this configuration, the provision of the first recess 7a1 makes it easier for the lower end portion 7a4 of the lower seal portion 7a to be slightly displaced radially inward. Therefore, the frictional force between the lower seal portion 7a and the sliding surface 6b1 when the lifting member 9 is pressed down can be reduced.

[0049] The piston 7 includes an upper seal portion 7b that extends upward from the radially outer end of the central base portion 7c and abuts against the cylinder member 6 at least at the top dead center (see FIG. 5) of the lifting member 9. In this embodiment, the upper seal portion 7b has a protrusion 7b1 that protrudes radially inward at its upper end, and at least at the top dead center (see FIG. 5) of the lifting member 9, the protrusion 7b1 abuts from the radially outer side against a contact tubular portion 6a9 of the upper cylinder member 6a that hangs down from the top of the cylinder member 6, radially inward of the sliding surface 6b1 of the cylinder member 6.

[0050] With the above configuration, when the lifting member 9 is pressed down and the upper seal portion 7b of the piston 7 is vertically spaced apart from the abutment tubular portion 6a9 (see FIG. 7 ), the lifting member 9 is released from the depressed state. The spring force of the spring 11 moves the lifting member 9 upward, and the upper seal portion 7b of the piston 7 again abuts against the abutment tubular portion 6a9 from the radially outer side. At this time, the upper seal portion 7b of the piston 7 is likely to be displaced radially outward due to the abutment of the protrusion 7b1 against the abutment tubular portion 6a9. Therefore, the lower seal portion 7a of the piston 7 is likely to move radially inward, thereby weakening the frictional force with the sliding surface 6b1. Therefore, the frictional force between the piston 7 and the cylinder member 6 when the lifting member 9 moves upward is reduced, allowing the lifting member 9 to be lifted without getting caught. As shown in FIG. 6 , the radially outer surface of the lower end of the abutment tubular portion 6a9 preferably has an R-shaped surface 6a10 that slopes radially outward from the bottom to the top. With this configuration, when the piston 7 moves upward relative to the cylinder member 6, the upper seal portion 7b can be smoothly and minutely displaced radially outward.

[0051] On the other hand, as shown in FIG. 9 , when the upper seal portion 7b of the piston 7 abuts against the contact tubular portion 6a9 from the radially inner side, the upper seal portion 7b of the piston 7 is displaced radially inward as the protrusion 7b1 abuts against the contact tubular portion 6a9. Therefore, the lower seal portion 7a of the piston 7 is likely to move radially outward, potentially increasing the frictional force with the sliding surface 6b1. However, even in the embodiment shown in FIG. 9 , the lower end portion 7a4 of the lower seal portion 7a is provided with a first recess 7a1 and two second recesses 7a2. The provision of the first recess 7a1 and the second recess 7a2 makes it easier for the lower end portion 7a4 of the lower seal portion 7a to displace radially inward. Therefore, even in the embodiment shown in FIG. 9 , the frictional force between the lower seal portion 7a and the sliding surface 6b1 when the lifting member 9 is pressed down can be reduced.

[0052] The mounting cap 5 includes a mounting tube 5a that is threadedly attached to the outer circumferential surface of the mouth portion 3a, an annular top wall 5b that extends radially inward from the upper end of the mounting tube 5a, and a guide tube 5c that extends upward from the inner circumferential edge of the top wall 5b and guides the press-down head 9a as it ascends and descends. The upper cylinder member 6a has a flange portion 6a1 that is sandwiched between the upper end surface of the mouth portion 3a and the top wall 5b. The mounting tube 5a of the mounting cap 5 has a restricting protrusion 5a1 that abuts against the outer circumferential edge of the flange portion 6a1 to prevent it from slipping downward from the upper end of the inner circumferential surface of the mounting tube 5a. The restricting protrusion 5a1 extends continuously or intermittently in the circumferential direction. A packing 13 is provided on the underside of the flange portion 6a1 and is sandwiched between the flange portion 6a1 and the upper end surface of the mouth portion 3a.

[0053] As shown in FIG. 5 , the lower cylinder member 6b has a sliding surface 6b1 and a lower cylinder peripheral wall 6b3 centered on the central axis O. The lower cylinder bottom 6b4 is connected to the lower end of the lower cylinder peripheral wall 6b3. The lower cylinder bottom 6b4 has a through-hole 6b7 through which the contents 4 pass. The valve body support portion 10a1 is held at the lower end of the lower cylinder peripheral wall 6b3. The lower cylinder peripheral wall 6b3 has a fitting hole 6b5 that penetrates the lower cylinder peripheral wall 6b3 radially above the sliding surface 6b1, and a guide groove 6b6 that extends from the upper end of the lower cylinder peripheral wall 6b3 along the inner circumferential surface of the lower cylinder peripheral wall 6b3 to just before the fitting hole 6b5. The guide groove 6b6 is formed as a recess that does not penetrate the lower cylinder peripheral wall 6b3 radially and opens upward. The lower end of the guide groove 6b6 forms a guide surface whose radial depth gradually decreases downward. The fitting hole 6b5 and the guide groove 6b6 are provided at the same circumferential position and with the same width.

[0054] As shown in FIG. 5 , the upper cylinder member 6a has an upper cylinder peripheral wall 6a2 extending downward from the inner peripheral edge of the flange portion 6a1. The upper cylinder peripheral wall 6a2 is inserted into the lower cylinder peripheral wall 6b3 of the lower cylinder member 6b and contacts the inner peripheral surface of the lower cylinder peripheral wall 6b3 above the sliding surface 6b1. The upper cylinder peripheral wall 6a2 has a fitting protrusion 6a3 protruding radially outward. The fitting protrusion 6a3 passes downward through the guide groove 6b6 and fits into the fitting hole 6b5, restricting the upward movement of the upper cylinder member 6a relative to the lower cylinder member 6b. The lower surface of the fitting protrusion 6a3 is inclined radially outward from the bottom to the top, and the upper surface extends horizontally. The upper cylinder peripheral wall 6a2 also has a stopper surface 6a4 that abuts against the lower cylinder peripheral wall 6b3 to restrict the downward movement of the upper cylinder member 6a relative to the lower cylinder member 6b. In this embodiment, the stopper surface 6a4 is provided in a stepped shape on the outer peripheral surface of the upper cylinder peripheral wall 6a2 and abuts against the upper end surface of the lower cylinder peripheral wall 6b3, but is not limited to this. The upper cylinder member 6a and the lower cylinder member 6b are fitted together by inserting the fitting protrusion 6a3 into the guide groove 6b6, pushing the upper cylinder member 6a toward the lower cylinder member 6b, and abutting the stopper surface 6a4 of the upper cylinder member 6a against the upper end surface of the lower cylinder peripheral wall 6b3, whereby the fitting protrusion 6a3 enters and engages with the fitting hole 6b5.

[0055] In this embodiment, four sets of fitting holes 6b5, guide grooves 6b6, and fitting protrusions 6a3 are provided at equal intervals in the circumferential direction. However, the number of sets of fitting holes 6b5, guide grooves 6b6, and fitting protrusions 6a3 provided in the cylinder member 6 is not limited to this. The upper cylinder member 6a and the lower cylinder member 6b are each formed by injection molding of a resin material.

[0056] The upper cylinder member 6a has a protective portion 6a5 that covers the upper seal portion 7b from above. In this embodiment, the protective portion 6a5 protrudes radially outward from a contact tubular portion 6a9 that hangs down from a spring bearing portion 6a6 at the lower end of the upper cylinder peripheral wall 6a2. The lower surface of the protective portion 6a5 extends downward toward the radially outward direction. The provision of the protective portion 6a5 prevents excessive displacement of the upper seal portion 7b of the piston 7. The protective portion 6a5 prevents the lifting member 9 from slipping out upward from the lower cylinder member 6b.

[0057] The upper cylinder member 6a has a spring receiving portion 6a6 extending radially inward from the lower end of the upper cylinder peripheral wall 6a2. The spring receiving portion 6a6 is composed of an annular wall 6a7 extending radially inward and a cylindrical wall 6a8 extending upward from the inner peripheral edge of the annular wall 6a7, and the lower end of a spring portion 11 is fitted between the cylindrical wall 6a8 and the upper cylinder peripheral wall 6a2. The spring portion 11 is an annular spring that surrounds the stem 9b1 in a plan view and is a resin compression spring that expands and contracts in the vertical direction. The upper end of the spring portion 11 supports the pressing head 9a. The spring portion 11 is not limited to being made of resin and may be made of metal, for example.

[0058] The lower cylinder member 6b preferably has higher lubricity than the upper cylinder member 6a in order to improve slidability on the sliding surface 6b1. Lubrication of the lower cylinder member 6b can be achieved by selecting a material with higher lubricity than the upper cylinder member 6a, or by molding the lower cylinder member 6b from a resin material to which a lubricant such as a higher fatty acid metal salt has been added (mixed). Lubrication may also be achieved by applying a lubricant such as silicone after the lower cylinder member 6b is formed. Among the above methods, adding a lubricant to impart lubricity is preferred from the viewpoint of productivity. For example, if the lower cylinder member 6b and the upper cylinder member 6a are molded from the same resin material, it is preferable not to add or apply a lubricant to the upper cylinder member 6a.

[0059] According to this embodiment, the cylinder member 6 is composed of an upper cylinder member 6a that is held by fitting into the attachment cap 5, and a lower cylinder member 6b that has a sliding surface 6b1 and is more lubricious than the upper cylinder member 6a, so that it is possible to achieve both the slidability of the piston 7 on the sliding surface 6b1 and the fitting force of the upper cylinder member 6a to the attachment cap 5. Note that the cylinder member 6 may be composed of a single member that has the sliding surface 6b1.

[0060] As explained above, the discharge implement 2 of the second embodiment comprises the attachment cap 5 attached to the opening 3a of the container 3, the cylinder member 6 held by the attachment cap 5 and having the sliding surface 6b1, the piston 7 sliding up and down on the sliding surface 6b1, the pump chamber 8 defined by the cylinder member 6 and the piston 7, and the elevating member 9 having the discharge port 9a1 and moving up and down with the piston 7 relative to the cylinder member 6 to send and discharge the contents 4 from inside the container 3 through the pump chamber 8 to the discharge port 9a1. The piston 7 has a base end 7a5 and a lower end that is inclined radially outward from the base end 7a5 downward and slides on the sliding surface 6b1. The lower seal portion 7a has a bent portion 7a3 between a base end 7a5 and a lower end 7a4, and an upper seal portion 7b extending upward and abutting against the cylinder member 6 at least at the top dead center of the elevating member 9. The lower seal portion 7a has a bent portion 7a3 between a base end 7a5 and a lower end 7a4, where the angle of inclination changes discontinuously, and the lower end 7a4 below the bent portion 7a3 has a larger angle of inclination downwardly and radially outward than the base end 7a5 above the bent portion 7a3. The radially inner surface of the lower seal portion 7a is provided with a first recess 7a1 that overlaps with the bent portion 7a3 or is provided adjacent to and below the bent portion 7a3 and is recessed radially outward. By adopting this configuration, the angle of inclination downwardly and radially outward at the lower end 7a4 of the lower seal portion 7a is made larger, allowing the lower end 7a4 of the lower seal portion 7a to slide more reliably against the sliding surface 6b1 of the cylinder member 6 for sealing. Furthermore, by providing the first recess 7a1 in the lower seal portion 7a, the lower end portion 7a4 of the lower seal portion 7a can be easily displaced radially inward when the lifting member 9 is pressed down. This reduces the frictional force between the lower seal portion 7a and the sliding surface 6b1 when the lifting member 9 is pressed down. Furthermore, when the piston 7 is molded in a mold, a shape corresponding to the first recess 7a1 can be provided on the core (male mold) side, making it easier for the molded piston 7 to engage with the concave and convex portions on the core side. With this configuration, when the mold is opened, the piston 7 can be easily engaged with the core side, facilitating release from the cavity (female mold), and the piston 7 can be easily removed from the mold.

[0061] In the second embodiment, one or more second recesses 7a2 are provided below the first recesses 7a1. This configuration allows the lower end 7a4 of the lower seal portion 7a to be more easily displaced radially inward when the lifting member 9 is pressed down, compared to when only the first recesses 7a1 are provided. This more reliably reduces the frictional force between the lower seal portion 7a and the sliding surface 6b1 when the lifting member 9 is pressed down.

[0062] In the second embodiment, the upper end of the upper seal portion 7b has a protrusion 7b1 that protrudes radially inward, and is configured so that at least at the top dead center of the lifting member 9, the protrusion 7b1 abuts from the radially outer side against a contact tubular portion 6a9 that hangs down from the upper part of the cylinder member 6, radially inward of the sliding surface 6b1 of the cylinder member 6. With this configuration, when the lifting member 9 is pressed down and the upper seal portion 7b of the piston 7 is released from a state in which it is vertically spaced apart from the abutment tubular portion 6a9 (see FIG. 7), the lifting member 9 moves upward due to the biasing force of the spring portion 11, and the upper seal portion 7b of the piston 7 again abuts against the abutment tubular portion 6a9 from the radially outer side. At this time, the upper seal portion 7b of the piston 7 is likely to be displaced radially outward as the protrusion 7b1 abuts against the abutment cylindrical portion 6a9, and the lower seal portion 7a of the piston 7 is likely to move radially inward, thereby weakening the frictional force with the sliding surface 6b1. Therefore, the frictional force between the piston 7 and the cylinder member 6 when the lifting member 9 moves upward is reduced, and the lifting member 9 can be lifted without getting caught.

[0063] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be modified in various ways without departing from the gist of the present invention.

[0064] For example, in the second embodiment, the upper seal portion 7b of the piston 7 is configured not to slide on the sliding surface 6b1 of the cylinder member 6, but the present invention is not limited to this, and the upper seal portion 7b of the piston 7 may be configured to slide together with the lower seal portion 7a on the sliding surface 6b1 of the cylinder member 6. When the upper seal portion 7b of the piston 7 slides on the sliding surface 6b1 of the cylinder member 6, a first recess 7a1 and a second recess 7a2 may also be provided on the upper seal portion 7b side.

[0065] REFERENCE SIGNS LIST 1 Discharge container 2 Discharge pump (discharge tool) 3 Container 3a Mouth portion 3b Body portion 4 Contents 5 Mounting cap 5a Mounting tube 5a1 Restricting protrusion 5b Top wall 5c Guide tube 6 Cylinder member 6a Upper cylinder member 6a1 Flange portion 6a2 Upper cylinder peripheral wall 6a3 Fitting protrusion 6a4 Stopper surface 6a5 Removal prevention portion (protective portion) 6a6 Spring receiving portion 6a7 Annular wall 6a8 Cylindrical wall 6a9 Contacting tube portion 6a10 R-surface 6b Lower cylinder member 6b1 Sliding surface 6b2 Vent hole 6b3 Lower cylinder peripheral wall 6b4 Lower cylinder bottom 6b5 Fitting hole 6b6 Guide groove 6b7 Through hole 7 Piston 7a Lower skirt portion (lower seal portion) 7a1 First recess 7a2 Second recess 7a3 Bent portion 7a4 Lower end portion 7a5 Base end portion (of lower seal portion) 7b Upper skirt portion (upper seal portion) 7b1 Projection portion 7c Central base portion 7d Lower contact portion 7e Upper contact portion 8 Pump chamber 9 Elevating member 9a Press-down head 9a1 Discharge port 9b Stem portion 9b1 Stem 9b2 Piston guide 9c Internal flow path 9d Opening / closing portion 10 Suction valve 10a Elastic valve 10a1 Valve body support portion 10a2 Elastic valve body 11 Spring portion 12 Outside air introduction path 13 Packing O Central axis

Claims

1. A discharge pump comprising: an attachment cap attached to the mouth of a container; a cylinder member held by said attachment cap and having a sliding surface; a piston that slides up and down on said sliding surface; a pump chamber defined by said cylinder member and said piston; and an elevating member having a discharge port and moving up and down relative to said cylinder member together with said piston to send and discharge the contents from within said container to said discharge port via said pump chamber, wherein said cylinder member comprises an upper cylinder member held by said attachment cap, and a lower cylinder member attached to and held by said upper cylinder member and having said sliding surface.

2. The discharge pump according to claim 1, wherein the upper cylinder member has a retaining portion that prevents the lifting member from slipping out upward from the lower cylinder member.

3. A discharge pump as claimed in claim 1 or 2, wherein the lower cylinder member has a lower cylinder peripheral wall having the sliding surface, the lower cylinder peripheral wall having a fitting hole penetrating the lower cylinder peripheral wall above the sliding surface in the radial direction and a guide groove extending from the upper end of the lower cylinder peripheral wall along the inner surface of the lower cylinder peripheral wall to just before the fitting hole, the upper cylinder member has an upper cylinder peripheral wall that contacts the inner surface of the lower cylinder peripheral wall above the sliding surface, the upper cylinder peripheral wall having a fitting protrusion that protrudes radially outward, and the fitting protrusion passes downward through the guide groove and fits into the fitting hole.

4. A discharge pump as claimed in any one of claims 1 to 3, wherein the mounting cap has a mounting tube attached to the outer peripheral surface of the mouth portion and a top wall extending radially inward from the upper end of the mounting tube, the upper cylinder member has a flange portion held between the upper end surface of the mouth portion and the top wall, and the mounting tube of the mounting cap has a restricting protrusion that abuts against the outer peripheral edge of the flange portion to prevent it from slipping downward from the upper end of the inner peripheral surface of the mounting tube.

5. A discharge pump as claimed in any one of claims 1 to 4, wherein the piston has a base end, a lower seal part having a lower end that slopes radially outward downward from the base end and slides on a sliding surface, and an upper seal part that extends upward and abuts against the cylinder member at least at the top dead center of the elevating member, wherein the lower seal part has a bent part between the base end and the lower end that is a transition position where the angle of inclination changes discontinuously, and the lower end below the bent part has a larger angle of inclination radially outward downward than the base end above the bent part, and a first recess that is recessed radially outward is provided on the radially inner surface of the lower seal part, overlapping the bent part or located adjacent to and below the bent part.

6. The discharge pump according to claim 5, further comprising one or more second recesses below the first recess.

7. A discharge pump as described in claim 5 or 6, wherein the upper end of the upper seal portion has a protrusion that protrudes radially inward, and at least at the top dead center of the lifting member, the protrusion abuts from the radially outer side against a contact cylindrical portion that hangs down from the top of the cylinder member, radially inward of the sliding surface of the cylinder member.

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