EP1310305B1

EP1310305B1 - Trigger type liquid discharge device

Info

Publication number: EP1310305B1
Application number: EP03000944A
Authority: EP
Inventors: Tadao c/o Yoshino Kogyosho Co. Ltd. Saito; Shigeru c/o Yoshino Kogyosho Co. Ltd. HAYAKAWA
Original assignee: Yoshino Kogyosho Co Ltd
Current assignee: Yoshino Kogyosho Co Ltd
Priority date: 1994-10-26
Filing date: 1995-10-26
Publication date: 2008-06-25
Anticipated expiration: 2015-10-26
Also published as: EP1923143A3; CA2179888A1; JP3720054B2; EP0738542A4; KR100407125B1; DE69535779D1; WO1996013334A1; AU3754095A; CA2179888C; CN1137764A; EP1923143B1; EP1923143A2; EP0738542B1; EP0738542A1; CN1071599C; AU708396B2; DE69535748D1; EP1310305A3; EP1310305A2

Description

Field of the Invention

This invention relates to an improved trigger type liquid discharge device to be fitted to an opening of a liquid container containing liquid in order to discharge the liquid.

Prior Art

Figure 5 of the accompanying drawings illustrates a known trigger type liquid discharge device disclosed in U.S. Patent No. 4,819,835 and so designed as to be fitted to the opening of a liquid container containing liquid in order to discharge the liquid.
In the known trigger type liquid discharge device as disclosed in U.S. Patent No. 4,819,835 , a pump unit E is arranged in parallel with a horizontally disposed discharge pipe unit F as illustrated in Figure 5.
The trigger type liquid discharge device as illustrated in Figure 5 is provided with a fitting section 101 by which the liquid discharge device is secured to an opening of a liquid container. When a trigger 102 of the device is pushed in a direction indicated by arrow J', a pushing member 103 by turn depresses a transversal groove 105 of a head 104 of piston unit G of the device so as to move a piston I until an end face 106 of the piston I abuts a bottom wall 107 of a cylinder H. Thus, the liquid filled in a cylinder chamber 108 is pushed out of the device through a liquid suction/discharge port 109 to a liquid flow path 110 so as to push a discharge valve body 111 under its pressure.
The discharge valve body 111 has a resiliently deformable section 112, which is resiliently deformed under the pressure of the liquid to open discharge valve seat 113. Thus, liquid is allowed to flow into a flow path 115 of the discharge pipe F through discharge valve chamber 114. Then the liquid flows into another flow path 116 and then a shallow groove M arranged between a liquid guide L and a short pipe K of a nozzle head J. Then, the liquid flows into still another flow path 117 in which spins the liquid, and is finally discharged through a discharge aperture 118.
Meanwhile, the piston I compresses a spring 119 contained in the piston unit. A ball valve 120 also contained in the unit is forced to abut a suction valve seat 121 under the pressure applied by the liquid of the flow path 110.
After completing to discharge the liquid through the discharge aperture 118, and if the trigger 102 is released, the piston is returned to a position shown in Figure 5 by the resilient force of the spring 119 to expand the cylinder chamber 108 so as to generate a negative pressure in the chamber 108. Such negative pressure acts on the discharge valve body 111 and the ball valve 120 to cause the discharge valve body 111 to firmly abut and close the discharge valve seat 113. Consequently, the ball valve 120 is moved away from the suction valve seat 121 to allow liquid in the liquid container to flow through a suction pipe 122, the liquid flow path 110 and the port 109 into the cylinder chamber 108 so that the device is made ready for another discharge operation.
The cylinder H is provided in a part of its peripheral wall with an air intake port 123. The air intake port 123 is held in communication with the liquid container, on which the device is mounted by means of the fitting section 101 of the device, through air ducts 124 and 125.
The piston I has a stroke end side resilient annular skirt 126 extending toward the bottom wall 107 of the cylinder H and an approach end slide resilient annular skirt 127 extending toward the opening of the cylinder H. Said annular skirts 126 and 127 are held in close contact with the inner wall of the cylinder.
When the piston I is located in a stroke end position where the end surface 106 abuts the bottom wall 107 of the cylinder H, an edge 128 of the approach end side annular skirt 127 is positioned beyond the air intake port 123 of the cylinder H toward the bottom wall 107. Under this condition, air is introduced into the liquid container as the air intake port 123 communicates with an opening 129 of the cylinder H that is exposed to the atmosphere. If, to the contrary, the piston I is located at an approach end position as indicated in Figure 5, the air intake port 123 is closed as it is positioned between the two annular skirts 126 and 127 so that no liquid would flow out through the air intake port 123 if the liquid container is tumbled down by mistake.
The trigger type liquid discharge device as disclosed in U.S. Patent No. 4,819,835 and summarily described above functions correctly so long as a user uses it properly and operates the trigger in such a way that the piston completely moves from the stroke end position to the approach end position.
In Figure 5, reference symbol N denotes a cap for covering the discharge aperture 117 and reference symbol O denotes a pivot of the cap N.
While the trigger type liquid discharge device as disclosed in U.S. Patent No. 4,819,835 operates satisfactorily efficiently for discharging liquid, it is accompanied by certain drawbacks particularly in terms of the pressure of the liquid flowing from the cylinder chamber 108 to the discharge aperture 118 during liquid discharging operation. More specifically, referring to Figure 6, during time TS from when the piston I starts moving from the approach end toward the stroke end, the liquid pressure PS in the shallow groove M and the flow path 117 which constitutes a spinning groove does not rise high enough to give rise to a jet stream of liquid. During time TE from the end of a liquid discharge phase when the piston I reaches to the stroke end and stops discharging liquid, residual pressure PE is found over a large area including the cylinder chamber 108, the port 109, the liquid path 110 and the discharge chamber 114.
As a result, liquid may drip out from the discharge aperture 118 at the beginning and the end of a discharge phase. When liquid is discharged as foam, large bubbles of liquid that have not sufficiently foamed may come out through the aperture. The trigger type liquid discharge device of the prior art has such drawbacks.
A trigger type liquid discharge device having the features set out in the preamble of the accompanying claim 1 is disclosed in prior EP-A-0 295 767 .

SUMMARY OF THE INVENTION

It is an aim of the present invention to provide a trigger type liquid discharge device having a configuration substantially as shown in Fig. 5 and improved such that no liquid drips out through the discharge aperture of the device even in the initial and final stages of the operation of activating the trigger and still the device satisfactorily operates for discharging liquid.
According to the present invention, there is provided a trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe (F) having a discharge aperture, and a trigger for reciprocating the piston, wherein liquid drawn up from the container is discharged through the discharge aperture by movement of the piston to a stroke end, wherein
a short and shallow groove is provided at a boundary between an outer surface of said inner sleeve and a bottom wall of the cylinder, and
an annular skirt of the piston is inserted into the short and shallow groove upon the stroke end, so that a liquid flow path communicates to the inside of the container through a gap between the inner surface of the piston and the outer surface of the inner sleeve, characterised in that
the said cylinder of the pump unit has an inner sleeve, and
said bottom wall of the inner sleeve of the cylinder is formed with a hole at a centre thereof, said hole communicating to an upper end of a liquid flow path, said liquid flow path communicating to the container. This addresses the foregoing aim by providing a trigger type liquid discharge device wherein the residual pressure in the pump mechanism can be removed by using the liquid flow path which is arranged out of the pump mechanism. Thus, it is easy to design the mechanism for sucking out the air.
Preferably, the hole is closed by a resilient valve which resiliently contacts to an outer surface of the bottom wall, and
a pin body is provided at a centre of the piston toward the bottom wall of the cylinder, and is so provided that when the piston reaches at a stroke end, a front end of the pin body resiliently deforms the resilient valve through the hole so that a cylinder chamber communicates to the liquid flow path. This addresses the foregoing aim by providing a trigger type liquid discharge device wherein the tolerance of the cylinder and the piston etc. of the pump mechanism does not affect the removal of the residual pressure from the pump mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a longitudinal sectional view of part of a discharge device having a pump mechanism in accordance with the present invention, showing when the piston gets to the approach end;
Figure 2 is a longitudinal sectional view similar to Figure 1 but showing the residual pressure clearing stroke;
Figure 3 is a longitudinal sectional view of a further embodiment in accordance with the present invention and showing when the piston gets to the approach end;
Figure 4 is a longitudinal sectional view of the embodiment of Figure 3, showing the residual pressure clearing stroke;
Figure 5 is a longitudinal sectional view of a conventional trigger type liquid discharge device; and
Figure 6 is a graph showing the relationship between the elapsed time and the discharge pressure in an entire phase of operation of a trigger type liquid discharge device as shown in Figure 5.

THE PREFERRED EMBODIMENTS

For the purpose of the present invention, all the components of a trigger type liquid discharge device according to the invention operate similarly as their counterparts of a conventional trigger type liquid discharge device illustrated in Figure 5 and described above except the nozzle head section and the pump unit. Thus, those components that are similar to or the same as their counterparts of Figure 5 should be referred. Throughout Figures 1 to 4, the same and identical components are denoted by the same reference symbols.
Figures 1 and 2 show an embodiment in accordance with the present invention.
A cylinder 91 of a pump unit 90 has an inner sleeve 92. A piston 93 has annular skirts 94 and 95 that resiliently abut an inner peripheral wall of the cylinder 91 and another annular skirt 96 resiliently abuts an outer peripheral wall of the inner sleeve 92. A hole 98 is bored in a bottom wall 97 of the inner sleeve 92 and communicates with an upper end of a liquid flow path 99 formed in the bottom wall 97 and communicating by turn with the inside of the container.
A short and shallow groove 301 is peripherally provided on the outer peripheral surface of the inner sleeve 92 along a connecting section of said outer peripheral surface of the inner sleeve 92 and the bottom wall 100 of the cylinder 91 in such a way that, when the piston 93 gets to the stroke end as shown in Figure 2, the edge of the annular skirt 96 gets into the short and shallow groove 301 and a gap is formed between said edge and a bottom of the short and shallow groove 301.
In order to allow air to enter the container from the atmosphere, an air intake port 302 is formed on the cylinder wall in a position close to the open end of the cylinder than the position of the annular skirt 95 when the piston 93 gets to the stroke end.
In this embodiment, when the piston 93 gets to the stroke end as shown in Figure 2, the edge of the annular skirt 96 gets into the short and shallow groove 301 and a gap is formed between the edge and the bottom of the groove so that any residual pressure that may exist in a liquid flow path 303, a remaining portion 305 of a cylinder chamber 304 and a port 306 may escape from the internal space of the piston 93 into the container through said gap, a gap between an inner peripheral surface 307 of the piston 93 and an outer peripheral surface 308 of the inner sleeve 92, the internal space of the inner sleeve 92, the hole 98 of the bottom wall 97 and the liquid flow path 99 as indicated by an arrow. Thus, any dripping of liquid due to the residual pressure may be effectively prevented from taking place.
In this embodiment, since any residual pressure that may exist around the pump unit 90 is removed by way of the short and shallow groove 301 of the inner sleeve 92 of the cylinder 91 and the hole 98 of the bottom walls 97, 100 and the liquid flow path 99, a greater extent of freedom is allowed in designing an outer air introducing structure in a form other than an air intake port 302 in order to prevent negative pressure from taking place within the container.
It may be needless to say that said short and shallow groove 301 can be replaced by a low projecting ridge running longitudinally.
Figures 3 and 4 illustrate a further embodiment in accordance with the present invention. A cylinder 310 of a pump unit 310 is provided in a bottom wall 311 thereof with a coaxial sleeve 314 for receiving a spring 313 for urging back a piston 312. At a position on an outer surface of the bottom wall 311 and facing a liquid guide pipe 317 having a check valve 315 and a liquid flow path 316, the cylinder 310 is provided with a liquid flow path 319 communicating with the inside of the container. Said spring receiving sleeve 314 is provided at an axial centre of its bottom wall 320 with a hole 321 communicating said liquid flow path 319.
The liquid guide pipe 317 is provided in its outer peripheral wall facing said hole 321 with an annular groove 322. The annular groove 322 is provided with an annular resilient valve 323. An upper edge of said resilient valve 323 is sandwiched by the liquid guide pipe 317, an outer surface of the bottom wall 311 and a grasping sleeve 318. A suspending sleeve section 325 of the resilient valve 323 closes said hole 321 from the outside.
The piston 312 has annular skirts 326 and 327 which resiliently abut the inner peripheral surface of the cylinder 310. The piston 312 has a pin body 330 arranged at the axial centre thereof and projecting from an inner surface of a piston head 328 at the approach end side toward the stroke end side. When the piston 312 gets to the stroke end, a front end 331 of the pin body 330 passes through the hole 321. The resilient valve 323 closing said hole 321 from outside resiliently deforms as shown in Figure 4 so as to release the closed condition of the hole 321.
As the closed condition of the hole 321 is released by the front end 331 of the pin body 330, any residual pressure that may exist in the liquid flow path 316, the cylinder chamber 332 and the port 333 may escape into the container when the piston 312 gets to the stroke end to terminate the liquid discharge cycle, so that any dripping of liquid due to the residual pressure may be effectively prevented from taking place.
Since the residual pressure is removed by positively causing the front end 331 of the pin body 330 to deform the resilient valve 323, any possible leakage of pressure and insufficient removal of residual pressure due to an accumulated effect of dimensional errors of the related components can be completely avoided to make the operation of dimensional control during the process of manufacturing the components very easy.

Claims

A trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe (F) having a discharge aperture, and a trigger for reciprocating the piston, wherein liquid drawn up from the container is discharged through the discharge aperture by movement of the piston to a stroke end, wherein
a short and shallow groove (301) is provided at a boundary between an outer surface of said inner sleeve (92) and a bottom wall (100) of the cylinder (91), and
an annular skirt (96) of the piston (93) is inserted into the short and shallow groove (301) upon the stroke end, so that a liquid flow path (303) communicates to the inside of the container through a gap between the inner surface of the piston (93) and the outer surface of the inner sleeve (92), characterised in that
the said cylinder (91, 310) of the pump unit has an inner sleeve (92) and
said bottom wall (97, 311) of the inner sleeve (92) of the cylinder (91, 310) is formed with a hole (98, 321) at a centre thereof, said hole (98, 321) communicating to an upper end of a liquid flow path (99, 319), said liquid flow path (99, 319) communicating to the container.
A trigger type liquid discharge device according to claim 1, characterised in that
the hole (321) is closed by a resilient valve (323) which resiliently contacts to an outer surface of the bottom wall (311), and
a pin body (330) is provided at a centre of the piston (312) toward the bottom wall (311) of the cylinder (310), and is so provided that when the piston (312) reaches at a stroke end, a front end (331) of the pin body (330) resiliently deforms the resilient valve (323) through the hole (321) so that a cylinder chamber (332) communicates to the liquid flow path (319).