VALVE UNIT AND CONTAINER

Abstract

 A valve unit sucks out liquid within a container main body to the outside. There are included a sucking up pipe, a bellows of zigzag shape, a shaft case, a piston shaft, and a piston head. A first check valve is provided upstream of the bellows, and a second check valve is provided downstream of the bellows. Between the shaft case and the piston shaft, there is provided an engagement portion which engages them together. The piston shaft does not interfere with the second check valve when the engagement portion is engaged, while, when the engagement portion is not engaged and moreover the piston head is engaged with the opening portion of the container main body, the second check valve is fixed in the open state.

Description

TECHNICAL FIELD

[0001] The present invention relates to a valve unit and a container which are used as a pump type container for, for example, shampoo or the like to be used in a household context.

BACKGROUND OF THE INVENTION

[0002] In the past, a pump type container has been used as a container for storing, for example, shampoo or detergent or the like which is used in a household context. This pump type container is composed of a container main body and a valve unit which is inserted into this container main body so as to be attachable thereto and detachable therefrom. The valve unit is normally made so that, when a piston portion is pressed, the piston portion returns and the liquid is sucked up from the container main body, and, when next the piston portion is pressed, the liquid is expelled from a discharge end of the piston portion.

[0003] To explain this example in terms of FIGS. 12 and 13, the valve unit 1 consists of a pipe type valve main body 2 which is inserted into a container main body not shown in the figures so as to be attachable thereto and detachable therefrom, and a piston portion 3 of a pipe type in the form of a letter "L".

[0004] The piston portion 3 is slidably inserted within the valve main body 2, and a liquid reception section 6, which connects to the atmosphere via the piston portion 3, is formed between a sucking aperture 4 of the valve main body 2 and a piston 5 at the tip portion of the piston portion 3. Furthermore, on the side of the sucking aperture 4 of this liquid storage portion 6, there is provided a first check valve B which only permits flowing in of liquid to the liquid storage portion 6 side from the container main body side, while furthermore, between the discharge end of the piston portion 3 and the discharge side of the liquid storage portion 6, there is provided a second check valve G which only permits flowing out of liquid to the piston portion 3 from the liquid storage portion 6; and a coil spring 7 is inserted between the piston 5 and the first check valve B. In addition, due to this coil spring 7, the piston 3 comes to be biased with respect to the valve main body 2 in the direction to increase the volume of the liquid storage portion 6.

[0005] It should be understood that, as shown by the respective arrow signs, FIG. 12 shows a state in which the piston portion has been pushed in, while FIG. 13 shows a state in which the piston portion 3 has returned.

[0006] However, with the above described prior art valve unit, there is the problem that the work of assembly is troublesome, because it is necessary to insert the coil spring 7 between the piston 5 and the sucking aperture 4.

[0007] Furthermore, with regard to the increasing demands for recycling of products from the point of view of protection of the natural environment, there is the obstruction with regard to recyclability since the coil spring 7 which is made from metal normally must be separated to waste it.

[0008] In addition, since the coil spring 7 is used, there is the problem that the number of man-hours for assembly and the number of parts are increased, which entails an increase of cost.

[0009] Furthermore, with a container which incorporates the valve unit, it has also been the case that the problem has occurred that, although normally the liquid in the container main body does not escape to the outside provided that the piston portion 3 is not pressed, if the container falls over during transportation or the like, the liquid flows out from the piston portion 3, since the first check valve B and the second check valve G open, which is undesirable.

[0010] The present invention has been performed in consideration of these circumstances, and it takes as its objective to provide a valve unit and a container, for which the work of assembly is easy and which can be manufactured at low cost, which moreover can be recycled easily, and which prevents escape of liquid even if they fall over.

DISCLOSURE OF THE INVENTION

[0011] The valve unit (10) described in Claim 1 is a valve unit (10) which is inserted into a container main body (12) and sucks out liquid within the container main body (12) to the outside of the container main body (12), characterized in that:
a sucking up pipe (21) which is inserted into the container main body (12) is provided; a bellows (22) of a zigzag shape which can return in its extension direction, is connected at an upper portion of this sucking up pipe (21) so as to communicate therewith; a pipe type shaft case (16) is connected at an upper portion of the bellows (22) so as to communicate therewith; a pipe type piston shaft (30) is inserted into an upper portion side of the shaft case (16) so as to be shiftable with respect to the shaft case (16); a piston head (20) is connected to an upper tip portion of the piston shaft (30) so as to be communicated therewith; a first check valve (23) which permits liquid only to flow in from the interior of the container main body (12) to the interior of the bellows (22), is provided at the upstream of the bellows (22); a second check valve (24) which permits liquid only to flow from the interior of the bellows (22) to the side of the shaft case (16), is provided at the downstream of the bellows (22); an engagement portion (35) which engages the piston shaft (30) to the shaft case (16) so as to be attachable thereto and detachable therefrom, is provided between the shaft case (16) and the piston shaft (30); a holding portion (39) which engages to the opening portion of the container main body (12) and is fixed thereto, is provided to the piston head (20); and the piston shaft (30) is made so that it does not interfere with the second check valve (24) when the engagement portion (35) is engaged, and so that, when the engagement portion (35) is not engaged and moreover the piston head (20) is engaged to the opening portion of the container main body (12) by its holding portion (39) and is fixed thereto, the second check valve (24) is fixed in its closed state.

[0012] The valve unit (10) described in Claim 2 is a valve unit (10) as described in Claim 1, characterized in that the engagement portion (35) which is provided between the shaft case (16) and the piston shaft (30), is composed of an engagement groove (34) which is formed upon a one of the shaft case (16) and the piston shaft (30) and an engagement projection (33) which is formed upon the other one thereof, and at least one of these is formed in a tapered shape, so that this piston shaft (30) and this shaft case (16) are engaged together by being mutually rotated in a one relative rotational direction, while this engagement is released by them being rotated in the opposite direction.

[0013] The valve unit (10) described in Claim 3 is a valve unit (10) as described in Claim 2, characterized in that a pressed in section (22b) is formed at an upper portion of the bellows (22); the bellows (22) and the shaft case (16) are connected together so as to be mutually communicated by the pressed in section (22b) being pressed into the shaft case (16); a guide groove (16a) is formed upon the shaft case (16); and a rib (22c) which engages to the guide groove (16a) is provided upon the pressed in section (22b) of the bellows (22).

[0014] The valve unit (10) described in Claim 4 is a valve unit (10) as described in Claim 1, characterized in that an opening portion of the container main body (12) is formed by a bush cap (15) which is attached to the container main body (12) and moreover into which the shaft case (16) is inserted, and in that an air hole (18) is formed in the bush cap (15) which connects together a gap between this bush cap (15) and the shaft case (16) and the interior of the container main body (12).

[0015] The valve unit (10) described in Claim 5 is a valve unit (10) as described in Claim 4, characterized in that the piston head (20) is connected to the piston shaft (30) in a state of having some play therebetween, and; between the bush cap (15) and the shaft case (16) which is inserted into it, a stopper portion (32) which prevents the rotation of the shaft case (16) in the circumferential direction without impeding its shifting in the insertion direction, is provided.

[0016] The valve unit (10) described in Claim 6 is a valve unit (10) as described in Claim 1, characterized in that a valve body (28) of the second check valve (24) comprises a bowl shaped portion (28a) which is open facing the downstream side.

[0017] The valve unit (10) described in Claim 7 is a valve unit (10) as described in Claim 1, characterized in that the sucking up pipe (21), the first check valve (23), the bellows (22), and the second check valve (24) are formed as a unit.

[0018] The valve unit (10) described in Claim 8 is a valve unit (10) as described in Claim 7, characterized in that the piston head is connected to the piston shaft (30) in a state of having some play therebetween, and; portions of the sucking up pipe (21), the first check valve (23), the bellows (22), and the second check valve (24) which are formed as a unit are fixed to a case (17) which is disposed so as to be fixed in the opening portion of the container main body (12) and moreover to cover over the bellows (22).

[0019] The container described in Claim 9 is characterized in that it comprises a valve unit (10) as described in Claim 1, and a container main body (12) to which this valve unit (10) is fitted so that it may be freely attached and removed.

[0020] The valve unit (10) described in Claim 10 is a valve unit (10) which is inserted into a container main body (12) and sucks out liquid within the container main body (12) to the outside of the container main body (12), characterized in that: there are provided a sucking up pipe (21) which is inserted into the container main body (12); a bellows (22) of a zigzag shape which can return in its extension direction and which is connected to an upper portion of this sucking up pipe (21) so as to communicate therewith and which can return in its extension direction; a piston portion (40) which is connected to an upper portion of the bellows (22) so as to communicate therewith, which expands and compresses the bellows (22), and which sucks up liquid within the container main body (12) via the sucking up pipe (21) out from the container main body (12); and wherein a first check valve (23) which permits liquid only to flow in from the interior of the container main body (12) to the interior of the bellows (22), is provided at the upstream of the bellows (22) ; a second check valve (24) which permits liquid only to flow from the interior of the bellows (22) to the side of the piston portion (40), is provided at the downstream of the bellows (22); and the bellows (22) is made of low density polyethylene, and when its liquid inhalation capacity is taken as X cc, its thickness is formed as 0.1X to 0.4X, and moreover the angle θ which is defined by the outer surfaces of its ridge portions (22d) is 80°±15°.

[0021] The valve unit (10) described in Claim 11 is a valve unit (10) as described in Claim 10_, characterized in that the bellows (22) is formed so that the ratio (d1/d2) of this trough radius d1 and this ridge radius d2 is formed as (0.90±0.05) X/3.

[0022] The valve unit (10) described in Claim 12 is a valve unit (10) as described in Claim 10, characterized in that: the piston portion (40) is made up from a pipe type shaft case (16) which is connected to an upper portion of the bellows (22) so as to communicate therewith and guards the opening portion of the container main body (12), a pipe type piston shaft (30) is inserted into an upper portion side of the shaft case (16) so as to be shiftable with respect to the shaft case (16), and a piston head (20) is connected to an upper tip portion of the piston shaft (30) so as to communicate therewith; an engagement portion (35) which engages the piston shaft (30) to the shaft case (16) so as to be attachable thereto and detachable therefrom, is provided between the shaft case (16) and the piston shaft (30); a holding portion (39) which engages to the opening portion of the container main body (12) and is fixed thereto, is provided to the piston head (20); and the piston shaft (30) is made so that it does not interfere with the second check valve (24) when the engagement portion (35) is engaged, and the second check valve (24) is fixed in its closed state when the engagement portion (35) is not engaged and moreover the piston head (20) is engaged to the opening portion of the container main body (12) by its holding portion (39) and is fixed thereto.

[0023] The container (11) described in Claim 13 is characterized by comprising a valve unit (10) as described in Claim 10, and a container main body (12) to which this valve unit (10) is fitted so as to be freely attached and removed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 

FIG. 1 is a sectional side view showing the overall structure of an embodiment of a valve unit of the present invention and of a container which incorporates it.

FIG. 2 is a sectional side view of a bellows unit in the valve unit shown in FIG. 1.

FIG. 3 is a figure for explanation of liquid inhalation capacity, and therein

(a) is a figure showing a state in which the bellows has been compressed, while

(b) is a figure showing an initial extended state in which it has been returned from the state in which it was compressed.

FIG. 4 is a sectional side view of essential portions of the valve unit shown in FIG. 1, for explanation of the overall structure of a first check valve and of a second check valve.

FIG. 5 is a figure for explanation of a stopper portion between a bush cap and a shaft case, and is a view seen along the arrows A-A in FIG. 1.

FIG. 6 is a side view of a piston shaft.

FIG. 7 is a sectional side view of essential portions of the shaft case.

FIG. 8 is a view for explanation of the state of engagement between ribs of a pressed in portion of the bellows and guide grooves of the shaft case, and is a view seen along the arrows B-B in FIG. 1.

FIG. 9 is a sectional side view showing the state of the container shown in FIG. 1 when liquid leakage during transportation or the like has been prevented.

FIG. 10 is a sectional side view for explanation of the state of the container shown in FIG. 1 during use.

FIG. 11 is a graph showing the relationship of pressing force and response time, with respect to a ratio (d1/d2).

FIG. 12 is an overall structural view of an exemplary prior art container, and is a sectional side view showing the valve unit thereof in the lowered states

FIG. 13 is an overall structural view of the exemplary prior art container, and is a sectional side view showing the valve unit thereof in the raised state.

BEST MODES FOR CARRYING OUT THE INVENTION

[0025] In the following, the valve unit and the container of the present invention will be explained in detail.

[0026] FIG. 1 is a figure showing an embodiment of the valve unit of the present invention and of a container which incorporates it; in FIG. 1, the reference symbol is the valve unit, while the reference symbol 11 is the container. The container 11 is one which is made up by the valve unit 10 being fitted to the container main body 12, in which shampoo in liquid form or the like is stored.

[0027] This container main body 12 is an element shaped as a tube with a bottom, and is formed from synthetic resin, with an external threaded portion 13 being formed at an upper opening portion 12a thereof. A bush cap 15 made from synthetic resin is attached to the opening portion 12a by an internal threaded portion 14 with which it is provided being screwingly engaged with the external threaded portion 13, and, by this bush cap 15 being attached, the valve unit 10 comes to be fitted to the container main body 11. Since the bush cap 15 is an element which comprises an external tube portion 15a formed with the external threaded portion 13, and an internal tube portion 15b which is inserted into the opening portion 12a of the container main body 12 and is fitted thereto, it is one for which the hole (not shown in the drawing) of the internal tube portion 15b defines an opening of the container main body 12, and herein the shaft case 16 of the valve unit 10 is inserted and is capable of sliding movement.

[0028] A case 17 which is made from synthetic resin is fitted in the opening portion 12a of the container main body 12, and is fitted facing the interior of the container main body 11, and the bush cap 15 is fitted in the opening portion 12a via this case 17. In particular, the internal tube portion 15b is one which is screwingly attached to the internal surface of the case 17 and is fixed thereto. Furthermore, air holes 18 which connect together the gap between the internal tube portion 15b and the shaft case 16, and the interior of the container main body 12, are formed in the internal tube portion of this bush cap 15 and the case 17. Yet further, in the upper portion of this bush cap 15, there is formed an external threaded portion 15c which constitutes an engagement between it and a piston head which will be described hereinafter.

[0029] The valve unit 10 is an assembly which comprises the case 17, a bellows unit 19 which is made from synthetic resin and which is arranged in this case 17 in the state of being inserted therethrough, and a piston head 20 which is made from synthetic resin and is attached to this bellows unit 19. The bellows unit 19 is an element for being inserted into the container main body 12 and for sucking out the liquid within the container main body 12 to the exterior of the container main body 12. In this bellows unit 19 there is provided a sucking up pipe 21 which; as shown in FIG. 2, is inserted within the container main body 12. This sucking up pipe 21 is an element at a lower end thereof is formed a sucking up end 21a by cutting at a sloping angle.

[0030] A zigzag shaped bellows 22 is connected to the upper end side of this sucking up pipe 21 in a connected through state, so as to be able to extend and to return in its extension direction. This bellows 22 is one which is made from low density polyethylene, and is made so as to be easily compressed by being pressed upon so that its internal volume is reduced, and also, when the pressing force is released, so as easily to return to its original state, in other words so as easily to return in its extension direction, so that its internal volume expands; and it is endowed with a predetermined spring constant, and its interior constitutes a liquid inhalation section.

[0031] Here, the difference between the volume of this bellows 22 when it is in its compressed state as shown in FIG. 3(a), and its volume when it has returned from its compressed state as shown in FIG. 3(b), in other words when it is in its initial extended state in which no pressing force is being applied, will be termed its liquid inhalation capacity X [units cc]. For example, according to the type or the like of the liquid which is charged into the container main body 12, this X may be one of a 1 cc type, or one of a 3 cc type, or the like. It should be understood that, if the liquid is a shampoo, a 3 cc type or the like is desirably utilized as the bellows 22, since the amount of shampoo which is normally used in one time of hair washing is around 6 cc.

[0032] Furthermore, for the bellows 22, the thickness of the tube body which constitutes its zigzag shape is made to be greater than or equal to 0.1 X [units mm], and moreover less than or equal to 0.4 X [units mm]; and, desirably, it is made to be greater than or equal to 0.5 X/3 [units mm], and moreover less than or equal to 1.0 X/3 [units mm]. Here, X denotes the liquid inhalation capacity, as previously described. Furthermore, the angle θ subtended by the outer surfaces of the ridge portions 22d upon the zigzag shape of the bellows 22, in the state in which the bellows 22 is not being subjected to any pressing force and is in its initially extended state as shown in FIG. 3(b), is made to be 80°±15°.

[0033] By making the bellows 22 from low density polyethylene (such as, for example, Novatec LL (a trademark) which is a linear type low density polyethylene made by Nippon PolyChem Co. Ltd.), and by keeping each of its thickness and the angles θ of its ridge portions 22d in the above-described range, this bellows 22 comes to be one which functions excellently, since, when it has been shortened, in other words has been compressed by being pressed, it returns to its original state (extends) upon release of the pressing force, without interposition of any metallic coil spring as in the prior art.

[0034] It should be understood that, when the thickness of the bellows 22 is less than 0.1 X [units mm], then the elastic restoration force becomes insufficient since it is too thin, and this is not desirable, since the response after the bellows 22 has been compressed, in other words the time period until it returns to its original state after the pressing force has been released, becomes longer than the range of time period which is desired. On the other hand, if this thickness exceeds 0.4 X [units mm], then since the bellows 22 is too thick the pressing force when compressing it is undesirably greater than the range of pressing force which is desired, and this is not desirable, since the convenience of use is decreased.

[0035] Furthermore, if the angle θ subtended by the outer surfaces of the ridge portions 22d of the bellows 22 is less than 65°, then the elastic return force becomes insufficient and the response becomes slower than the range of time period which is desired, which is not desirable. On the other hand, if it is greater than 95°, then the pressing force when compressing the bellows 22 exceeds the range of pressing force which is desired, which is not desirable either.

[0036] Furthermore, with this bellows 22, in particular the liquid within the container main body 12 is one which is of a type which is used by pressing a plurality of times, and, if for example the liquid is a shampoo and the liquid inhalation capacity of the bellows 22 is one of a 1 cc type or a 3 cc type or the like, then, in the zigzag shape, the ratio (d1/d2) between the outer diameter of the trough portions 22e, in other words the trough diameter d1, and the outer diameter of the ridge portions 22d, in other words the ridge diameter d2, is desirably made to be (0.9±0.05) X/3. If the ratio (d1/d2) between the trough radius d1 and the ridge radius d2 is set to be within this range, as is shown by sample experiments which will be described hereinafter, the response after the bellows 22 has been compressed becomes quick, and accordingly, if the liquid within the container main body 12 is to be used by pressing a plurality of times, in particular the convenience of use is improved.

[0037] The shaft case 16 is fixed to the upper end side of this type of bellows 22 by being pressed thereinto, as shown in FIG. 2.

[0038] Furthermore, a first check valve 23 is provided at the upstream side of the bellows 22, in other words between the sucking up pipe 21 and the bellows 22, and permits only the flow in of liquid from the container main body 12 to within the bellows 22. Furthermore, a second check valve 24 is provided at the downstream side of the bellows 22, in other words between the bellows 22 and the shaft case 16, and permits only the flow out of liquid from within the bellows 22 to the side of the piston head 20.

[0039] The first check valve 23 is formed as one unit with the sucking up pipe 21, and is formed as provided with a valve chamber 25; while the second check valve 24 is one which is formed as one unit with the connection portion 22a of the upper end of the bellows 22, and is formed as provided with a valve chamber 26. Here, a pipe type pressed in section 22b is formed in the connection portion 22a of the upper end of the bellows, further to upper portion thereof. This pressed in section 22b is an element which is pressed into the shaft case 16 and is fixed to the shaft case 16, as previously described. And in this pressed in section 22b there are formed ribs 22c which, as will be described hereinafter, engage to the guide grooves 16a of a shaft case 16. It should be understood that the bellows unit 19 comes to be in the state of penetrating a lower opening 17a of the case 17 at the spot of the valve chamber 25 of the first check valve 23, as shown in FIG. 1.

[0040] Within the valve chambers 25 and 26, there are inserted and disposed valve bodies 27, 28 which can be inserted from the sucking up end 21a of the sucking up pipe 21, or from the upper opening side of the pressed in section 22b of the bellows 22. These valve bodies 27, 28, in this example, are both elements which are made from synthetic resin, and which are formed to have bowl shaped portions 27a (28a) which open facing towards the downstream side (the shaft case 16 side). It should be understood that, with regard to these valve bodies 27, 28, provided that they are ones which can close the lower apertures 25a (26a) of the valve chambers 25 (26), they are not limited to this shape, and ones of a spherical shape or a hemispherical shape or the like are also acceptable.

[0041] Both the valve body 27 for the first check valve 23 and the valve body 28 for the second check valve 24, as shown in FIG. 4, are elements which are formed with rod portions 27b (28b) extending to the upstream side on the outer sides (the lower sides) of the central portions of the bowl shaped portions 27a (28a), and the attitude of the bowl shaped portions 27a (28a) comes to be stabilized due to these rod portions 27b (28b).

[0042] The bowl shaped portions 27a (28a) are elements whose outer peripheral surfaces are formed as arcs, and these outer peripheral surfaces are made so as closely to contact to the inner peripheral surface of the valve chamber 31. Here, with regard to these bowl shaped portions 27a, 28a, they are elements whose sealing characteristics are enhanced by their thickness being made thin, or by forming them from a soft material.

[0043] A notched portion 27c shaped as a letter "V" is formed in the circumferential edge of the bowl shaped portion 27a of the valve body 27 for the first check valve 23. And, due to this type of structure, when the first check valve 23 is in the opened state, the valve body 27 comes to allow escape of liquid or of air from the notched portion 27c. Furthermore, in the second check valve 24, a pair of projecting portions 29, 29 are formed on the downstream side within its valve chamber 26, and, due to this, the valve body 28 comes not to be able to float upwards higher than these projecting portions 29, 29. It should be understood that, provided that it is possible to prevent the floating upwards of the valve body 28, it would be possible to employ some other construction instead of these projecting portions 29, 29; for example, it would also be acceptable to make the cross sectional shape of the valve chamber 26 itself to be a special cross section such as an elliptical shape, a quadrilateral shape, a triangular shape or the like, such that the valve body 28 cannot float upwards.

[0044] The shaft case 16 is a pipe type element which, by being pressed into the pressed in section 22b of the bellows 22 as shown in FIGS. 1 and 2, is fixed in a state of being communicated to these, and a piston shaft 30 is shiftably inserted into the upper end side of its upper portion. A larger diameter portion 31 is formed at the vicinity of the central portion of its outer peripheral surface of the shaft case 16, in the state of extending outwards therefrom. This larger diameter portion 31, as shown in FIG. 1, is an element which functions as a stopper for ensuring, by contacting against the lower end surface of the internal tube portion 15b of the bush cap 15, that it cannot rise up higher than this. Furthermore, as shown in FIG. 5, a projection 32a which projects out to the outside is formed in the upper end side of the outer peripheral surface of the shaft case 16, while on the other hand a guide groove 32b is formed in the inner surface of the hole portion of the bush cap 15 which this projection 32a contacts, so that it engages with the projection 32a and guides it in the upwards and downwards direction, in other words from the upper surface side of the bush cap 15 towards its downward surface side. The projection 32a and the guide groove 32b according to this type of structure constitute a stopper portion 32 which does not hinder the shifting of the shaft case 16 in the insertion direction, while it prevents rotational movement in their circumferential direction.

[0045] A pair of engagement projections 33 are formed upon the piston shaft 30, and are positioned in mutually opposite positions upon its outer peripheral surface central portion, as shown in FIGS. 1 and 2. These engagement projections 33 are elements whose lower surface sides are made as tapered surfaces 33a, as shown in FIG. 6, and, as shown in FIG. 7, they are formed so as to engage to engagement grooves 34 which are formed upon the upper tip portion of the inner peripheral surface of the shaft case 16 so as to be attachable thereto and detachable therefrom, and the engagement section 35 of the present invention is constituted by these engagement projections 33 and engagement grooves 34.

[0046] Here, the engagement grooves 34 are made with tapered surfaces 34a upon the sides of their upper surfaces, and thereby, as will be described hereinafter, when the piston shaft 30 is rotated and its engagement projections 33 are engaged to the engagement grooves 43 of the shaft case 16, in the initial phase of this engagement state the engagement projections 33 and the engagement grooves 34 have some play between them due to the tapering surfaces 33a and the tapering surfaces 33b, while, by further turning from this state, the play is eliminated and the engagement projections 33 and the engagement grooves 34 come to be tightly engaged together. In other words, this structure provides for these engagement projections 33 and engagement grooves 34 to be engaged together by rotating the piston shaft 30 and the shaft case 16 in one direction, while this engagement may be released by rotating them in the opposite direction.

[0047] It should be understood that although, as previously described, the guide grooves 16a which engage with the ribs 22c along the longitudinal direction are formed upon the inner peripheral surface of the shaft case 16, it is arranged for the engagement projections 33 as well to be able to be engaged upon these guide grooves 16a so as to be capable of free sliding movement. In other words, when the piston shaft 30 is in a position in which it is not engaged to the shaft case 16, the engagement projections 33 come to be so that they are engaged in free sliding movement to the guide grooves 16a, and, due to this structure, the engagement projections 33 do not interfere with the inner peripheral surface of the shaft case 16, and it is arranged for them to be able to shift freely upwards and downwards within the shaft case 16.

[0048] Furthermore, as shown in FIG. 8, the previously described ribs 22c which are formed upon the pressed in section 22b of the bellows 22 are engaged to the lower end sides (the bellows 22 sides) of the guide grooves 16a, and due to this, along with the connection between the shaft case 16 and the bellows 22 coming to be reinforced, leakage of liquid from between these two members also comes to be prevented.

[0049] Furthermore, as shown in FIG. 6, the lower tip portion of the piston shaft 30 is arranged to be formed in a shape and of dimensions which correspond to the internal surface shape of the bowl shaped portion 28a of the valve body 28 of the second check valve 24, while a small diameter portion 36 for attaching the piston head 20 is formed at its upper tip portion.

[0050] The piston head 20 is the letter "L" shaped element which is fitted at the upper tip portion of the piston shaft 30, in other words, at the upper tip portion of the bellows unit 19 which is made from the structure shown in FIG. 2, and is able to revolve freely by the application of a predetermined force without being fixed thereto in a state of being fitted to the small diameter portion 36 with some play, as shown in FIG. 1, in other words when the piston shaft 30 is thus fixed. Furthermore, a discharge hole 37 which is connected to a hole (not shown in the figures) in the piston shaft 30, is formed in this piston head 20, and the open end of this discharge hole 37 constitutes a discharge aperture 38 for discharging liquid.

[0051] Furthermore, in this piston head 20, upon its lower inner peripheral surface, there is formed an internal threaded portion 39 which is helically engaged to the external threaded portion 15c of the bush cap 15, and due to this, the piston head 20 comes to be engaged to the bush cap 15 and fixed it, as shown in FIG. 9. It should be understood that the internal threaded portion 39 of the piston head 20 and the external threaded portion of the bush cap 15 constitute engagement portions which implement engagement between the piston head 20 and the bush cap 15 which in practice constitutes the opening portion of the container main body 12.

[0052] Here, the piston portion 40 of the present invention is made up from the piston head 20 made in this manner, the piston shaft 30, and the shaft case 16.

[0053] It should be understood that the valve unit 10 which constitutes an embodiment of the present invention is assembled by forming the sucking up pipe 21, the first check valve 23, the bellows 22, and the second check valve 24 which constitute the bellows unit 19 in a unitary manner by blow forming or the like, by assembling the shaft case 16 and the piston shaft 30 to these by pressing in or the like, and then, further, by fitting the case 17 to this bellows unit 19 in a state of being clipped over it, and, by fitting the piston head 20 to the piston shaft 30, along with fitting the bush cap 15 with this case 17 in a fixed state.

[0054] Next, the method of use of the container 11 equipped with the valve unit 10 having this type of structure will be explained.

[0055] During normal use, as shown in FIG. 1, first, the piston head 20 is rotated in a predetermined direction in its state in which it is pulled in the upwards direction, and the piston shaft 30 is turned along therewith and its engagement projections 33 are engaged with the engagement grooves 34 of the shaft case 16. At this time, while as previously described a degree of play is present for the initial rotational (initial engagement), due to the respective tapered surfaces 33a and 34a which are formed upon the engagement projections 33 and the engagement grooves 34, along with further rotation from this state, this play comes to be eliminated, and the engagement projections 33 and the engagement grooves 34 come to be firmly engaged together.

[0056] At this state, the liquid in the container main body 12 is to be sucked out, the piston head 20 is pressed down. As a result, due to the fixed engagement between the engagement projections 33 on the piston shaft 30 which is connected to the piston head 20 as previously described and the engagement grooves 34, the shaft case 16 is also lowered due to the lowering of the piston head 20 (the piston shaft 30), and the bellows 22 is compressed as shown in FIG. 10. At this time, if there is no liquid in the bellows 22, along with the compression of the bellows 22 the air in the bellows 22 is expelled, and due to this the valve body 27 of the first check valve 23 closes the lower aperture 25a with its bowl shaped portion 27a. On the other hand, the valve body 28 of the second check valve 24 opens the lower aperture 26a so as to discharge the air in the bellows 22, and via the shaft case 16 and the piston shaft 30, this air is discharged from the discharge aperture 38 of the piston head 20.

[0057] It should be understood that when the piston head 20 is pressed downwards in this manner and the bellows 22 is compressed, and the air in the bellows 22 is discharged, a negative pressure is engendered within the container main body 12. However, since the air hole 18 is formed in the bush cap which is fitted to the opening portion 12a of the container main body 12 and in the case 17, external air is taken into the container main body 12 due to this air hole 18, and the pressure within the container main body 12 stays the same as the external pressure (atmospheric pressure). Accordingly, it is ensured that no bad influence to be exerted upon the compression of the bellows or upon its return.

[0058] Next, when the pressing upon the piston head 20 is released, the bellows 22 returns in its expansion direction, and the system returns to its state shown in FIG. 1, so that a negative pressure is engendered within the bellows 22. As a result, the valve body 27 of the first check valve 23 opens the lower aperture 25a as shown by the double dotted line in FIG. 1, and due to this, the liquid is sucked into the bellows 22 from the container main body 12, and the interior of the bellows 22 is filled with the liquid.

[0059] After this, when the piston head 20 is pressed for a second time as shown in FIG. 10, the shifting of the liquid within the bellows 22 to the side of the container main body 12 is prevented since the valve body 27 of the first check valve 23 closing the lower aperture 25a. Furthermore, since the bellows 22 being compressed by the pressure force upon the piston head 20, the liquid within the bellows 22 presses the valve body 28 of the second check valve 24 upwards and opens the lower aperture 26a, and is pressed out to within the valve chamber 26. As a result, the liquid which is pressed out into the valve chamber 26 passes through the second check valve 24 to arrive at the shaft case 16. And then, due to the first check valve 23, this liquid does not flow in reverse into the container main body 12, and is discharged via the piston shaft 30 and the discharge hole 37 of the piston head 20 out from the discharge aperture 38.

[0060] Furthermore, when not in use such as during transportation or the like, the piston head 20 is turned in advance in the predetermined direction, in other words is turned in the direction opposite to the direction which engages together the previously described engagement projections 33 and engagement grooves 34, and the piston shaft 30 is rotated along therewith and releases the engagement together of its engagement projections 33 and the engagement grooves 34 of the shaft case 16.

[0061] In this state, the piston head 20 is pressed downward as shown in FIG. 9, and this piston head 20 is received in the bush cap 15. Furthermore, the piston head is rotated in the predetermined direction, and its internal threaded portion 39 is helically engaged with the external threaded portion 15c of the bush cap 15, and thereby the piston head 20 is engaged to the bush cap 15.

[0062] At this time, the action of the piston head 20 may be performed without any hindrance, since the piston head 20 is connected to the piston shaft 30 in a state wherein some play is present between them.

[0063] Furthermore, due to the engagement between the engagement projections 33 and the engagement grooves 34 having been released, the engagement projections 33 being engaged with the guide grooves 16a of the shaft case 16, and the piston shaft 30 is shifted without along with the shaft case 16, and falls to the interior of this shaft case 16. And then, in the position in which the piston head 20 is screwingly attached and engaged to the bush cap 15, the piston shaft 30 presses upon the valve body 28 of the second check valve 24 with its lower tip portion, and closes the lower aperture 26a of the valve chamber 26.

[0064] Accordingly, the second check valve 24 is closed due to the piston head 20 being screwingly attached and engaged to the bush cap 15 as previously described, and because of this, even when for example the container main body 12 has been inverted, flow out of the liquid in the container main body 12 is prevented.

[0065] Furthermore, at this time, since the piston shaft 30 is shifted without along with the shaft case 16, even when the piston head 20 is pressed downwards, the bellows 22 is not compressed due to the load applied thereby, and it is maintained in its extended free state. Accordingly, deformation of the bellows 22 due to it being maintained in its compressed state over a long time period comes to be reliably prevented.

[0066] In the valve unit 10 having this type of structure, and in the container 11 which incorporates it, it is possible to suck out the liquid within the container main body 12 by compression of the bellows which itself functions as a member for storing liquid, accordingly a member for storing the liquid becomes no longer necessary, as it is when using a coil spring, and thus it is possible to reduce the number of elements and the number of assembly processes.

[0067] Furthermore, since it is possible to manufacture the various members from synthetic resin, thereby performing disassembly recycling becomes easy, as compared with the case of using a coil spring, a first check valve, and a second check valve made from steel.

[0068] Yet further, during normal use, due to the engagement of the engagement portion 35 which consists of the engagement projections 33 and the engagement grooves 34, it is possible to operate the bellows 22 simply by actuating the piston head 20 (the piston shaft 30). On the other hand, during non use such as transportation or the like, by releasing the engagement of the engagement portion 35, and moreover by engaging and fixing the piston head 20 to the bush cap 15 which constitutes the opening portion of the container main body 12, it is possible to fix the second check valve 24 in the closed state with the piston shaft 30, and thereby, even if for example the container main body 12 is inverted, it is possible to prevent the liquid within the container main body 12 from flowing out to the outside, which would be undesirable. Furthermore, since at this time the bellows 22 is not compressed due to the load, but is maintained in its extended free state, accordingly, deformation of the bellows 22 due to it being maintained in its compressed state over a long time period comes to be reliably prevented.

[0069] Furthermore, since the bellows 22 is made from low density polyethylene, the thickness of the bellows 22 is made to be of a predetermined thickness which corresponds to its liquid inhalation capacity X, and moreover the outer surfaces of the ridge portions 22d are made to subtend angles θ of 80°±15°, thereby the bellows 22 comes to be made with a desired compressibility without the use of any coil spring made from metal, and accordingly the bellows 22 sucks liquid out from within the container main body 12 in a desirable manner. Therefore it becomes possible to avoid the obstacles such as occur with the prior art in the case in which a coil spring is used, that problems occur with the work of assembly and that disassembly upon recycling is difficult. Furthermore it is also possible to reduce the number of parts and the number of processes during assembly.

[0070] It should be understood that the present invention is not limited to the above-described embodiment; various changes of implementation are possible. For example, in the above embodiment, the stopper portion 32 was provided between the bush cap 15 and the shaft case 16 so as to prevent rotational movement in the circumferential direction of the shaft case 16 without hampering shifting in its through direction, however, it would also be acceptable, instead of this, to arrange for a portion of the sucking up pipe 21, the first check valve 23, the bellows 22, and the second check valve 24 which were formed as one unit, such as the portion where the first check valve 23 is formed for example as shown in FIG. 1, to be pressed into and fixed to the lower aperture 17a of the case 17.

[0071] With this type of structure as well, when the engagement portion 35 is engaged by the piston shaft 30 and the shaft case 16 being relatively rotated in one direction, or when this engagement is released by them being rotated in the opposite direction, it is possible to prevent undesirably turning of the shaft case 16 which causes difficulties in its rotational action.

[0072] Furthermore, with regard to the engagement portion 35, in the above-described embodiment it is composed of the engagement grooves 34 and the engagement projections 33, for example, however, it would also be acceptable to make this engagement portion 35 as an external threaded portion and an internal threaded portion. In other words, it would also be acceptable to form the engagement grooves as an internal threaded portion, and to form the engagement projections as an external threaded portion. With this structure as well, it is arranged for the piston shaft 30 and the shaft case 16 to be engaged together by being relatively mutually rotated in one direction, while this engagement is resealed by rotating the m in the opposite direction.

[0073] Furthermore, with regard to the structure of the piston portion 40 as well, it need not only be made from the shaft case 16, the piston shaft 30, and the piston head 20; it would also be acceptable to add various other elements, or, instead of these elements, to employ other elements.

(EXPERIMENTAL EXAMPLES)

[0074] Four types of bellows 22 were made with grade UE320 of Novatec LL (a trademark) made by Nippon PolyChem Co. Ltd., which is a linear type low density polyethylene.

[0075] Each of these four types of bellows had a liquid inhalation capacity X [units cc] of 3 cc, and the angle θ subtended by the outer surfaces of the ridge portions 22d upon the zigzag shape of the bellows 22 was approximately 80°, while the thickness of the tube body which defined the zigzag shape (the difference in thickness between the ridge portions 22d and the trough portions 22e) was in the range 0.5 ∼ 1.0 mm. It should be understood that, with these bellows, the number of the ridge portions 22d was 15, while the distance between the summits of adjacent ridge portions 22d, in other words the widths of the trough portions 22e, was 4 mm.

[0076] Furthermore, with regard to this ridge radius d2, it was made to be 18.2 mm for each of the bellows, while, with regard to the trough radius d1, this was made to be respectively 11.0 mm, 12.9 mm, 15.0 mm, and 16.4 mm. By doing this, the ratios (d1/d2) between the trough radius d1 and the ridge radius d2 became, respectively, as shown below:

With the one of trough radius d1 of 11.0 mm, about 0.6;

With the one of trough radius d1 of 12.9 mm, about 0.7;

With the one of trough radius d1 of 15.0 mm, about 0.8;

And with the one of trough radius d1 of 16,4 mm, about 0.9.

[0077] For each of the four types of bellows which were made in this manner, the pressing force (in kg) required to compress it, and the response time (in seconds) until it returned to its original state from the compressed state were measured. It should be understood that the compression by pressing was performed in the state in which the interior of the container was empty, and the pressing was maintained until the state shown in FIG. 3(a) was attained. In FIG. 11, the pressing forces and the response times which were obtained are shown with respect to the ratio (d1/d2) between the trough radius d1 and the ridge radius d2.

[0078] It will be understood from FIG. 11 that, with the ratio (d1/d2) about 0.9, the response time was quick at about 1 second, and accordingly, in a case such as when performing the discharge operation of liquid with the bellows a plurality of times, the convenience of use is particularly improved.

[0079] On the other hand, the smaller the ratio (d1/d2) became, the slower did the response time become and the smaller was the pressing force, and accordingly it will be understood that, in a case such as when the bellows is of a high capacity, and it will suffice to perform the operation of discharging liquid with it once, the convenience of use is particularly improved.

INDUSTRIAL APPLICABILITY

[0080] As has been explained above, since the valve unit described in Claim 1 is made so that there is provided a bellows which functions as a member which itself stores liquid, and so that it is possible for the liquid to be sucked out of the interior of the container main body by the extension and compression of the bellows, thus it becomes no longer necessary to provide a member for storing the liquid such as in the case when a spring is used, and accordingly it is possible to reduce the number of parts and the number of assembly processes.

[0081] Furthermore, since it is possible to make each of the members out of synthetic resin, it is possible to perform disassembly for recycling easily, by comparison to the case in which a coil spring, a first check valve, and a second check valve which are made from steel were used.

[0082] Furthermore, during normal use, by setting the engagement portion to be engaged, it is possible to prevent the shifting of the piston shaft within the shaft case and to make this shaft case and this piston shaft be as one unit, so that it is possible for the bellows to be operated simply by the piston shafts In addition, in non use as during transportation or the like, by releasing the engagement portion, and moreover by engaging the piston head by its holding portion to the opening portion of the container main body and fixing it there, it is possible to fix the second check valve in the closed state, and due to this it is possible, even if for example the container main body is inverted, reliably to prevent the liquid within the container main body from flowing out to the outside.

[0083] Furthermore, since at this time the piston shaft shifts without along with the shaft case, even if the piston head being pressed downwards, the bellows is not compressed due to the load which is applied thereby, but is maintained in its extended free state. Accordingly, deformation of the bellows due to a long time period elapsing with it being in the compressed state comes to be reliably prevented.

[0084] With the valve unit described in Claim 2, since the engagement portion which is provided between the shaft case and the piston shaft, is composed of an engagement groove which is formed upon a one of the shaft case and the piston shaft and an engagement projection which is formed upon the other one thereof, and at least one of these is formed in a tapered shape, so that this piston shaft and this shaft case are engaged together by being mutually rotated in one relative rotational direction, while this engagement is released by them being rotated in the opposite direction; thereby, by the operation of rotation, it is possible easily to perform engagement of the engagement portion and the release of its engagement, and due to this it is possible to provide excellent operability.

[0085] With the valve unit described in Claim 3, since a pressed in section is formed at an upper portion of the bellows, the bellows and the shaft case are connected together so as to be mutually communicated by the pressed in section being pressed into the shaft case, an engagement groove is formed upon the shaft case to constitute the engagement portion, and a rib which engages to the engagement groove is provided upon the pressed in section of the bellows; thereby, along with it being possible to strengthen the connection between the shaft case and the bellows, it is also possible to prevent liquid leakage between them.

[0086] With the valve unit described in Claim 4, since an opening portion of the container main body is formed by a bush cap which is attached to the container main body and moreover into which the shaft case is inserted, and an air hole is formed in the bush cap which connects together a gap between this bush cap and the shaft case and the interior of the container main body; when a negative pressure is engendered in the container main body due to the liquid in the container main body being sucked out, it is possible for the internal pressure within the container main body to be returned almost to atmospheric pressure which is the pressure outside by air passing via the gap through the air hole and flowing into the container main body, so that due to this no bad influence is exerted upon the operation of the bellows and so on.

[0087] With the valve unit described in Claim 5, since the piston head is connected to the piston shaft in a state of having some play therebetween, and between the bush cap and the shaft case which is inserted into it, a stopper portion which prevents the rotation of the shaft case in the circumferential direction without impeding its shifting in the insertion direction, is provided; when the engagement portion is engaged by the piston shaft and the shaft case being mutually relatively rotated in the one direction, or when this engagement is released by them being rotated in the opposite direction, it is possible to prevent the undesirably turning of the shaft case together with the bush cap which causes difficulties in its rotational action. Furthermore, when the piston head is engaged in the opening portion of the container main body, since the piston head is connected in the state of having some play between itself and the piston shaft, accordingly the action of the piston head is not hampered by the stopper portion.

[0088] With the valve unit described in Claim 6, since a valve body of the second check valve comprises a bowl shaped portion which is open facing the downstream side, when the liquid flows in reverse (which is undesirable), the bowl shaped portion of the valve body receives the pressure force of the liquid and quickly comes to shift in the closing direction. Furthermore, during transportation or the like when the unit is not being used, if the engagement of the engagement portion is released, and moreover the piston head is engaged to the opening portion of the container main body by its engagement portion and is fixed thereto, then, due to the valve body of the second check valve being provided with the bowl shaped portion, its inner side becomes easy to be pressed by the lower end of the piston shaft, and accordingly it is possible more reliably to fix the second check valve in the closed state.

[0089] With the valve unit described in Claim 7, since the sucking up pipe, the first check valve, the bellows, and the second check valve are formed as a unit, it is possible to anticipate large scale reduction of the number of component parts and of the number of processes of manufacture.

[0090] With the valve unit described in Claim 8, since the piston head is connected to the piston shaft in a state of having some play therebetween, and portions of the sucking up pipe, the first check valve, the bellows, and the second check valve which are formed as a unit are fixed to a case which is disposed so as to be fixed in the opening portion of the container main body and moreover to cover over the bellows; when the engagement portion is engaged by the piston shaft and the shaft case being mutually relatively rotated in the one direction, or when this engagement is released by them being rotated in the opposite direction, it is possible to prevent the undesirably turning of the shaft case which causes difficulties in its rotational action. Furthermore, when the piston head is engaged in the opening portion of the container main body, since the piston head is connected in the state of having some play between itself and the piston shaft, accordingly, for example, the action of the piston head is not hampered by the stopper portion.

[0091] With the container described in Claim 9, since there is included a valve unit as described in Claim 1, and a container main body to which this valve unit is fitted so that it may be freely attached and removed, it is possible to anticipate reduction of the number of component parts and of the number of processes of manufacture for the container as a whole. Furthermore, due to the piston shaft, even if for example during transportation or the like when it is not being used the container main body is inverted, it is possible to prevent the liquid in the container main body from flowing out to the outside. Furthermore, since at this time the piston shaft is shifted without along with the shaft case, even if the piston head is pressed downward, the bellows is not compressed due to the load which is applied, but is maintained in its free extended state. Accordingly, it is possible reliably to prevent deformation of the bellows due to its remaining in the compressed state for a long time period.

[0092] With the valve unit described in Claim 10, since, along with the bellows being made of low density polyethylene, also the thickness of the bellows is formed in a predetermined manner in correspondence to its liquid inhalation capacity X, and moreover the angle θ which is defined by the outer surfaces of its ridge portions is a predetermined angle; therefore, it is arranged for the expansion and compression of the bellows to be performed in a desirable manner without the use of a coil spring made from metal, and accordingly, since the bellows sucks out the liquid in the container main body in a desirable manner, it is possible to avoid problems during the assembly work or difficulties in disassembling the unit when it is to be recycled which are caused in case of the use of a coil spring such as in the prior art, and furthermore it is also possible to reduce the number of parts and the number of processes during assembly.

[0093] With the valve unit described in Claim 11, since the bellows is one which is formed so that the ratio (d1/d2) of its trough radius d1 and its ridge radius d2 is formed as (0.9±0.05) X/3, it is possible to make the response (the responsiveness) of the bellows as it returns after having been compressed be fast, and accordingly, in a case such as when a plurality of discharge action of liquid discharge by the bellows are to be performed, it is possible particularly to improve its convenience of use.

[0094] With the valve unit described in Claim 12, since the piston portion is made up from a pipe type shaft case which is connected to an upper portion of the bellows so as to communicate therewith and guards the opening portion of the container main body, a pipe type piston shaft which is inserted into an upper portion side of the shaft case so as to be shiftable with respect to the shaft case, and a piston head which is connected to an upper tip portion of the piston shaft so as to communicate therewith; an engagement portion which engages the piston shaft to the shaft case so as to be attachable thereto and detachable therefrom, is provided between the shaft case and the piston shaft; a holding portion which engages to the opening portion of the container main body and is fixed thereto, is provided to the piston head; and the piston shaft is made so that it does not interfere with the second check valve when the engagement portion is engaged, and so that, when the engagement portion is not engaged and moreover the piston head is engaged to the opening portion of the container main body by its holding portion and is fixed thereto, the second check valve is fixed in its closed state; therefore, during normal use, by setting the engagement portion to be engaged, thereby the shifting of the piston shaft within the shaft case is prevented and this shaft case and piston shaft are made to be one unit, and it is possible to operate the bellows simply with the piston shaft. Furthermore, even if for example during transportation or the like when it is not being used the engagement of the engagement section is released, and moreover, due to the piston head being engaged to the opening portion of the container main body by its holding portion and being fixed therein, it is possible to fix the second check valve in its closed state, thereby, when for example from this state the container main body is inverted, it is possible reliably to prevent the liquid in the container main body from flowing out to the outside. Furthermore, since the piston shaft 30 is shifted without along with the shaft case at this time, even if the piston head is pressed downward, the bellows is not compressed due to the load which is applied, but is maintained in its free extended state. Accordingly, it is possible reliably to prevent deformation of the bellows due to its remaining in the compressed state for a long time period.

[0095] With the container described in Claim 13, since there are comprised a valve unit as described in Claim 10, and a container main body to which this valve unit is fitted so as to be freely attached and removed, it is possible to anticipate reduction of the number of parts in the container as a whole, and of the number of assembly processes. Furthermore, due to the piston shaft, even if for example during transportation or the like when it is not being used the container main body is inverted, it is possible to prevent the liquid in the container main body from flowing out to the outside. In addition, since at this time the piston shaft is shifted without along with the shaft case, even if the piston head is pressed downward, the bellows is not compressed due to the load which is applied, but is maintained in its free extended state. Accordingly, it is possible reliably to prevent deformation of the bellows due to its remaining in the compressed state for a long time period.

Claims

1. A valve unit (10) which is inserted into a container main body (12) and sucks out liquid within the container main body (12) to the outside of the container main body (12), characterized in that:

a sucking up pipe (21) which is inserted into the container main body (12) is provided, a bellows (22) of a zigzag shape which can return in its extension direction is connected to an upper portion of this sucking up pipe (21) so as to communicate therewith, a pipe type shaft case (16) is connected to an upper portion of the bellows (22) so as to communicate therewith, a pipe type piston shaft (30) is inserted into an upper portion side of the shaft case (16) so as to be shiftable with respect to said shaft case (16), and a piston head (20) is connected to an upper tip portion of the piston shaft (30) so as to be communicated therewith;

a first check valve (23) which permits liquid only to flow in from the interior of the container main body (12) to the interior of the bellows (22) is provided at the upstream of said bellows (22), and a second check valve (24) which permits liquid only to flow out from the interior of the bellows (22) to the side of the shaft case (16), is provided at the downstream of the bellows (22);

an engagement portion (35) which engages the piston shaft (30) to the shaft case (16) so as to be attachable thereto and detachable therefrom, is provided between the shaft case (16) and the piston shaft (30);

a holding portion (39) which engages to the opening portion of the container main body (12) and is fixed thereto, is provided to the piston head (20), and

said piston shaft (30) is made so that it does not interfere with said second check valve (24) when said engagement portion (35) is engaged, and so that, when the engagement portion (35) is not engaged and moreover said piston head (20) is engaged to the opening portion of said container main body (12) by its holding portion (39) and is fixed thereto, said second check valve (24) is fixed in its closed state.

2. A valve unit (10) as described in Claim 1, characterized in that said engagement portion (35) which is provided between the shaft case (16) and said piston shaft (30), is composed of an engagement groove (34) which is formed upon a one of the shaft case (16) and the piston shaft (30) and an engagement projection (33) which is formed upon the other one thereof, and at least one of these is formed in a tapered shape, so that this piston shaft (30) and this shaft case (16) are engaged together by being mutually rotated in a one relative rotational direction, while this engagement is released by them being rotated in the opposite direction.

3. A valve unit (10) as described in Claim 2, characterized in that a pressed in section (22b) is formed at an upper portion of the bellows (22), and the bellows (22) and the shaft case (16) are connected together so as to be mutually communicated by said pressed in section (22b) being pressed into the shaft case (16); and
   a guide groove (16a) is formed upon the shaft case (16), and a rib (22c) which engages to said guide groove (16a) is provided upon said pressed in section (22b) of the bellows (22).

4. A valve unit (10) as described in Claim 1, characterized in that an opening portion of said container main body (12) is formed by a bush cap (15) which is attached to the container main body (12) and moreover into which said shaft case (16) is inserted, and in that an air hole (18) is formed in said bush cap (15) which connects together a gap between this bush cap (15) and the shaft case (16) and the interior of the container main body (12).

5. A valve unit (10) as described in Claim 4, characterized in that said piston head (20) is connected to the piston shaft (30) in a state of having some play therebetween, and
   between said bush cap (15) and the shaft case (16) which is inserted into it, a stopper portion (32) which prevents the rotation of the shaft case (16) in the circumferential direction without impeding its shifting in the insertion direction, is provided.

6. A valve unit (10) as described in Claim 1, characterized in that a valve body (28) of said second check valve (24) comprises a bowl shaped portion (28a) which is open facing the downstream side.

7. A valve unit (10) as described in Claim 1, characterized in that said sucking up pipe (21), said first check valve (23), said bellows (22), and said second check valve (24) are formed as a unit.

8. A valve unit (10) as described in Claim 7, characterized in that said piston head is connected to the piston shaft (30) in a state of having some play therebetween, and
   portions of said sucking up pipe (21), said first check valve (23), said bellows (22), and said second check valve (24) which are formed as a unit are fixed to a case (17) which is disposed so as to be fixed in the opening portion of the container main body (12) and moreover to cover over the bellows (22).

9. A container (11), characterized in that it comprises a valve unit (10) as described in Claim 1, and a container main body (12) to which this valve unit (10) is fitted so that it may be freely attached and removed.

10. A valve unit (10) which is inserted into a container main body (12) and sucks out liquid within the container main body (12) to the outside of the container main body (12), characterized in that:

there are provided a sucking up pipe (21) which is inserted into the container main body (12), a bellows (22) of a zigzag shape which can return in its extension direction and which is connected to an upper portion of this sucking up pipe (21) so as to communicate therewith and which can return in its extension direction, and a piston portion (40) which is connected to an upper portion of the bellows (22) so as to communicate therewith, which expands and compresses the bellows (22), and which sucks up liquid within the container main body (12) via said sucking up pipe (21) out from the container main body (12); wherein

a first check valve (23) which permits liquid only to flow in from the interior of the container main body (12) to the interior of the bellows (22), is provided at the upstream of said bellows (22); a second check valve (24) which permits liquid only to flow from the interior of the bellows (22) to the side of the piston portion (40), is provided at the downstream of the bellows (22); and said bellows (22) is made of low density polyethylene, and when its liquid inhalation capacity is taken as X cc, its thickness is formed as 0.1X to 0.4X, and moreover the angle θ which is defined by the outer surfaces of its ridge portions (22d) is 80°±15°.

11. A valve unit (10) as described in Claim 10, characterized in that said bellows (22) is formed so that the ratio (d1/d2) of its trough radius d1 and its ridge radius d2 is formed as (0.9±0.05) X/3.

12. A valve unit (10) as described in Claim 10, characterized in that:

said piston portion (40) is made up from a pipe type shaft case (16) which is connected to an upper portion of the bellows (22) so as to communicate therewith and guards the opening portion of the container main body (12), a pipe type piston shaft (30) which is inserted into an upper portion side of the shaft case (16) so as to be shiftable with respect to said shaft case (16), and a piston head (20) which is connected to an upper tip portion of the piston shaft (30) so as to communicate therewith;

an engagement portion (35) which engages the piston shaft (30) to the shaft case (16) so as to be attachable thereto and detachable therefrom, is provided between the shaft case (16) and the piston shaft (30);

a holding portion (39) which engages to the opening portion of the container main body (12) and is fixed thereto, is provided to the piston head (20); and

said piston shaft (30) is made so that it does not interfere with said second check valve (24) when said engagement portion (35) is engaged, and so that, when the engagement portion (35) is not engaged and moreover said piston head (20) is engaged to the opening portion of said container main body (12) by its holding portion (39) and is fixed thereto, said second check valve (24) is fixed in its closed state.

13. A container (11), characterized by comprising a valve unit (10) as described in Claim 10, and a container main body (12) to which this valve uni t (10) is fitted so as to be freely attached and removed.

Drawing