AU745856B2 - Trigger type liquid discharge device - Google Patents

Description

4 k Regulation 3.2

AUSTRALIA

Patents Act 1952 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

r Name of Applicant: Actual Inventors: Address for Service: Invention Title: Yoshino Kogyosho Co., Ltd.

2-6, Ojima 3-chome, Koto-ku, Tokyo 136, Japan SAITO, Tadao HAYAKAWA, Shigeru DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Trigger Type Liquid Discharge Device The following statement is a full description of this invention, including the best method of performing it known to us: 1 4 t' TRIGGER TYPE LIQUID DISCHARGE DEVICE 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 Fig. 33 of the accompanying drawings illustrates a known trigger type liquid discharge device disclosed in 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 liqc~u id.

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 Fig. 3:3.

The trigger type liLqu idc discharge device as illustrated in Fig. 33 is provided wvith a fitting sect ion 101 by which the liquid discharge device i~s secured to an opening of a liquid container. When a trigger 102 of the device is pushed in a direction indicated by arrow J1', a pushing member 10:3 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 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 Ill under its pressure.

The discharge valve body Ill has a resii. e 1;Ly(eLo rmab le section 112, which is resiliently deformed under the pressure or: the liquid to open discharge valve seat 11:3. Thus, liquid is allowed to flow into a flow path 115 of the discharge pipe I-, through discharge valve chamber 114. Then the liquid flows in to an another flow path 116 and then a shallow groove Mi arranged between a liquid guide L and a short pipe K of a nozzle head J.

Then, the liquid flows into a 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 Wn the piston unit. A ball valve 120 also containedI in the unlit i~s fo rced to abu t a su]ct;ion valve seat 121 unrder 1;he p ress ur e applied by the Iliquid of the f!low 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 Fig. :33 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 Ill and the ball valve 120 to cause the discharge valve body Ill 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 li quid in the li qu id( con ta.i ner to f low through a suction pipe 122. the liquid flow p~ath 110 and the p)ort 2* 109 into the cylinder chamber 108 so that the device ready 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 in take~ port 123 is held in communication with the li quiid con tai n er, on whic1 h t:he devic e is mounted by means of the fitting section 101 of the device, through air ducts 124 and 125.

The p is ton I has a stroke end sideI res i lient annular skirt 126 extending toward the bottom waill 107 of the cyli nderF H andc anl approach end side- resilient annular skirt 1;.27 exten1 i g towa rd the opening of the cylinder H. Said annular skirts 126 anld 127 are held in close contact with the inner wvall 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 sidIe annular skirt 127 is posi1.t ionedJ beyond the ai..r In take port 123 of the c:ylindIer 1 -1 toward the bottom wall 107. Under this condi tiLon, air is in troduced into the li qui.d( container as the a ir i.n take port 123 communicates wi th an open ing 1.29 the cylinde r H that is exposed to the atmosphere IfI, to the contrary thle p is ton I is located at an app roach end pos i tion as idicated in Fig 383, the air intake po)r t 128 is closed as it; is posit.ion ed be twe en the two annular ski rts 126 and 127 so that no) liquid would flow~ out through the air intake port 123 if the Iliquid container ins tumbled down by mistake.

The trigger type liquid discharge (device as disclosed in US Patent NC). 4,819,835 and summarily described above functions cor rec tly so long as a user uses it p roperly and operates the trigger in such a way that the pi.1ston compl etelIy moves from th'e stroke end position to the approach end position.

In Fig. 83, reference symbol N denotes a cap for coveri.ng I r the discharge aperture 117 and reference symbol 0 denotes a pivot of the cap N.

While the trigger type liquid discharge device as disclosed in US 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 f'rom the cylinder chamber 108 to the discharge aperture 118 during liquid discharging operation. 'More specif ically, retferring to Fig. 34, 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 li.quid 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 V L iquid 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.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a trigger type liquid discharge device having a configuration substantially as shown Ln Fig. 33 and improved such that no liquid drips out through the discharge aperture of the P:yrhC21905 12-rc- 1.d13/002 device even in the initial and final stages of the operation of activating the trigger and still the device satisfactorily operate for discharging liquid, or to at least provide a useful alternative to the prior art.

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 having a discharge aperture, and 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 an inner peripheral wall of the cylinder is provided with a plurality of short and shallow grooves at a portion adjacent to a bottom wall of the cylinder, said short and shallow grooves running longitudinally, the inner peripheral wall of the cylinder is provided with an air intake port communicating with an inside of the container, stroke end side end portion of the piston is formed 20 with a first annular skirt held in close contact with the inner peripheral wall of the cylinder, and an approach end side portion of the piston is formed with a second annular skirt held in close contact with the inner peripheral wall of the cylinder; and 25 a gap separating said first annular skirt and second annular skirt is so selected that, when the first annular ee skirt rides on the short and shallow grooves of the cylinder, the second annular skirt is in close contact with the inner peripheral wall of the cylinder at an edge portion of the air intake port.

The invention also provides a trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe 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 P. Ur 2l9051 2r- do- 1310202 -6a stroke end, wherein said cylinder of the pump unit comprises an outer sleeve and an inner sleeve concentrically within the outer sleeve, a short and shallow groove is circumferentially provided on an outer surface of the inner sleeve at a position adjacent to a bottom wall of the outer sleeve, and said piston is provided with a skirt which closely contacts with the outer surface of the inner sleeve, and is so arranged that when the skirt is positioned in the short and shallow groove, a liquid flow path communicates with the inside of the container through a gap between the skirt and the short and shallow groove, a port in the rear of the piston, grooves formed in an inner surface of an outer sleeve of the piston and an intake port of the outer sleeve of said cylinder.

The invention also provides a trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe having a discharge S 20 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 25said cylinder of the pump unit comprises an outer 25 sleeve and an inner sleeve concentrically within the outer sleeve, a bottom wall of an inner sleeve of the cylinder is formed with a hole therein, said hole communicating to an upper end of a liquid flow path, said liquid flow path communicating to the container, 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, P Vpcrash\2190512rs dit-13/02/02 an annular skirt of the piston is inserted into the short and shallow groove upon the stroke end, so that said liquid flow path communicates to the inside of the container through a gap between the skirt and the short and shallow groove, a port in the rear of the cylinder and through an intake port of the outer sleeve.

One embodiment of the invention relates to a trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe 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 hole is formed at a centre of a bottom wall of the cylinder, the hole communicates to a liquid flow path which *e 0..

g* 0* o*oooo SP:\OPER\GCP\37540. DIV 24/6/99 7 communicates to the inside of the container, 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.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an enlarged longitudinal sectional view of a first embodiment of liquid discharge device showing the inside of the device before it starts discharging liquid.

Fig. 2 is an enlarged longitudinal sectional view of the nozzle head of the embodiment of Fig. 1.

Fig. 3 is an enlarged front view of the nozzle head of Fig.

2 Fig. 4 is an enlarged lateral view of an integral structure 20 comprising a valve body, a pressure bearing sleeve, an anchoring 000.member and a spring member as shown in Fig. 1.

9. 9.

Fig. 5 is a front view of the integral structure of Fig. 4.

Fig. 6 is a rear view of the integral structure of Fig. 4.

Fig. 7 is an enlarged partially sectional lateral view of the integral structure of Fig. 4, obtained by rotating it by 900 from the position of Fig. 4.

Fig. 8 is an enlarged longitudinal sectional view of the embodiment of Fig. 1, showing the inside when it is discharging liquid.

30 Fig. 9 is an enlarged longitudinal sectional view of a second embodiment of liquid discharge device showing the inside of the device before it starts discharging liquid.

Fig. 10 is an enlarged lateral view of an outer member of the liquid guide of the embodiment of Fig. 9.

Fig. 11 is a rear view of the member of Fig. Fig. 12 is a lateral partially secti ona.l view of the member of Fig. 10, obtained by rotating it by 90 from the position of Fig. Fig. 13 is an enlarged lateral partially sectional view of an inner member of the liquid guide of the embodiment of Fig. 9.

Fig. 14 is a front view of the member of Fig. 13.

Fig. 15 is an enlarged longitudinal sectional view of the embodiment of Fig. 9, showing the inside when it is discharging liquid.

Fig. 16 is an enlarged longitudinal sectional view of the pump unit of a further embodiment of liquid discharge device showing the inside when it is in a standstill state.

Fig. 17 is an enlarged longitudinal sectional view of the pump unit of Fig. 16, showing the inside during an air intake phase.

Fig. 18 is an enlarged longitudinal sectional view of the pump unit of Fig. 17, showing the inside during a liquid discharge phase, showing the state after that of FIG. 17.

S: Fig. 19 is an enlarged longitudinal sectional view of the pump unit of Fig. 17, showing the inside when the discharging operation is finished and it is moved into a residual pressure relieving phase.

Fig. 20 is an enlarged longitudinal sectional view of the pump unit of a further embodiment of liquid discharge device, showing the inside during an air intake phase.

Fig. 21 is an enlarged longitudinal sectiona view of t Fig. 21 is an enlarged longitudinal sectional view of the P:\OPER\GCP\37540.DIV- 24/6/99 9 pump unit of Fig. 20, showing the inside during a residual pressure relieving phase.

Fig. 22 is an enlarged longitudinal sectional view of the pump unit of a further embodiment of liquid discharge device, showing the inside during a residual pressure relieving phase.

Fig. 23 is an enlarged longitudinal sectional view of the pump unit of a further embodiment of liquid discharge device, showing the inside during a liquid discharge phase.

Fig. 24 is an enlarged longitudinal sectional view of a further embodiment of pump mechanism, showing when the piston gets to the approach end.

Fig. 25 is an enlarged longitudinal sectional view similar to Fig. 24 but showing the residual pressure clearing stroke.

Fig. 26 is an enlarged longitudinal sectional view of a pump mechanism according to a further embodiment, showing when the piston gets to the approach end.

Fig. 27 is an enlarged longitudinal sectional view similar to Fig. 26 but showing the residual pressure clearing stroke.

oo Fig. 28 is an enlarged longitudinal sectional view of a 20 further embodiment and showing when the piston gets to the :.:eq approach end.

o° C Fig. 29 is an enlarged longitudinal sectional view of the c.embodiment of Fig. 28 showing the residual pressure clearing stroke.

Fig. 30 is an enlarged longitudinal sectional view according to a further embodiment.

Fig. 31 is an enlarged longitudinal sectional view of another embodiment.

Fig. 32 is an enlarged longitudinal sectional view of a 30 further embodiment of the liquid discharge device, showing a principal part thereof.

Fig. 33 is an enlarged longitudinal sectional view of a conventional trigger type liquid discharge device.

Fig. 34 is a graph showing the relationship between the elapsed time and the discharge pressure in an entire phase of P rs IAZ 190512rcs.dio- 13/02 operation of a trigger type liquid discharge device as shown in Fig. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Features of the preferred embodiments are hereinafter described in further detail, but by way of example only, with reference to the accompanying drawings.

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 Fig. 33 and described above except the nozzle head section and the pump unit. Thus, those components that are similar to or same as their counterparts of Fig. 33 should be referred. Throughout Figs. 1 to 32, same and identical components are denoted by same reference symbols.

Figs. 1 through 8 illustrate in enlarged views a nozzle head section 1 of a first embodiment of liquid discharge S: 20 device. The nozzle head section 1 comprises a nozzle head 2, a liquid guide 3, a spin element 4 and a nozzle tip 6 I having a discharge aperture The nozzle head 2 is provided with a valve seat 8 arranged in a liquid flow path 7 at a position upstream 25 relative to the o discharge aperture 5. Said l iquid flow path 7 communicates wvith the liquid flow path 115 of the discharge pipe un!Lt F viva a liquid flow path 9.

As shown in Figs 4 through 7 said l.iquid( guid (3 c omp riLse s a valve body 10 which abuts onl the valve seart 8 to close the liquid flow path 7, a pressure bearing sleeve 11 integrally formed witb the- valve body 10, an anchoring member 12 to be secured to the spin element 4 and a spring member 13 for coupling: the discharge valve 10 and the pressure bearing sleeve 11 to the anchoring member 12.

As shown in Figs. 5 and 7, the pressure bearing sleeve 1-1 has a pressure bearing surface 14 arranged to face the upstream side of the liquid flow path 7 for bearing liquid pressure.

As seen from Figs. .5 through 8, the valve body 1(0 and the pressure bearing s!leeve 11 is coupled by means of a sleeve provided wi[th a wvindow 16 which communicate sto the eliqcu idc flow path 9. As shown in Fig. 1, the pressure of the liquid is applied to the liquid bearing surface 14 when the valve body 10 abuts the valve seat 8 to block the liquid flow paths 7 and 9.

Said sleeve 15 is integrally formed with a guide sleeve 17 extending to the side of the liquid flow path 9. Said guide sleeve 17 is slidably inserted into the inside of a guide sleeve 18 of the spin element 4 projecting toward the liquid flow path 7, such that it may slidably move without encountering any significant resistance and hence the valve body 10 may move back and forth relative to the valve seat 8. keeping its proper posture The anchoring member 12 and the spring member 13 are arranged in an annular space 4C between the guide sleeve 18 and an outer sleeve 4B of the spin element 4.

As seen from Figs. 1, 2, 3 and 8, the nozzle head 2 has a recess 19 at the front end thereof for bearing and securing or holding the nozzle tip 6 in such a way that a flow path 20 is produced in the form of a spin groove.

Reference numeral 21 in the drawings denotes a bore for bearing the pivot 0 of the cap N shown in Fig. 33.

The nozzle head 2 is provided with an annular groove 2A for bearing a corresponding annular section 4A of the front end of the spin element 4, and an another annular groove 2B for tightly but slidably bearing the pressure bearing sleeve 11.

The nozzle head 2 is so designed that, after fitting the liquid guide 3 thereinto, an outer sleeve 2C is secured to the spin element 4 by means of undercuts 2D. Thus, these are easily assembled.

Referr ing to Fi.g. 1, the valve body 10 is pressed against the valve seat 8 in Fig. I under liquid pressure applied thereto within the horizontal projection surface area X and by the resilient force of the spring member 13.

On the other hand, the pressure bearing sleeve 11 is pressed toward the upstream of the liquid flow paths under liquid pressure applied to the horizontal projection surface area of the pressure bearing surface 14.

Therefore, by selecting an appropriate value for the horizontal projection surface area of the pressure bearing surface 14 such that the force generated by the proper liquid discharge pressure that is applied to said horizontal projection surface area of the pressure bearing surface 14 is greater than e*

I.

the sum of the force generated by the proper liquid discharge pressure that is applied to the horizontal surface area of' the valve body 10 and the resilient force of the spring member 13, the valve body 10 is moved and opened under liquid pressure the instance when the liquid pressure reaches the level of the proper liquid discharge pressure.

Thus, according to the invention, the valve body 10 is opened when the liquid pressure reaches the proper liquid discharge pressure Y as shown in Fig. 34 so that liquid is discharged in the direction indicated by arrow Z in Fig. 8. The valve body is closed when the liquid pressure f-alls under the proper liquid discharge pressure. Wi th such an arrangement, liquid can be effectively prevented from dripping out of the discharge aperture 5 in the initial and final stages of discharging liquid due to insufficient liquid pressure.

Figs. 9 through 15 show, in an enlarged scale, the nozzle head 201 of a second embodiment of liquid discharge device. While the nozzle head of the above described first embodiment comprises a one-piece liquid guide 3, the liquid guide 203 of the second embodiment comprises two pieces of an outer member 222 including a valve body 210 and an inner member 223.

Note that the nozzle head 202 including the nozzle tip 206 of this embodiment is otherwise structurally same as its counterpart of the first embodiment.

As shown in Figs. 10, 11 and 12, the outer member 222 of the liquid guide 203 comprises a valve body 210, a pressure bearing sleeve 211. an anchoring member 212 to be secured to the spin element 204. a spring member 213 and a guide sleeve 217.

The valve body 210 blocks the Liquid flow path 207 arranged on the side of the nozzle tip 206 and the upstream si de liquid flow path 209.

The spring member 213 couples the anchoring member 212 to the valve body 210, the pressure bearing sleeve 211 and the guide sleeve 217.

The inner member 223 shown in Figs. 13 and 14 is put into and rigidly secured to the guide sleeve 217. Said inner member 223 comprises a head section 224, a flange 225 and a slide sleeve 226.

The head section 224 is press-ft into a sleeve section 215 which is formed by extending from the valve body 210 of the outer member 222 toward the upstream side of the liquid flow paths.

The flange 225 is press-fit into the guide sleeve 217.

The slide sleeve 226 is slidably inserted into the inside of guide sleeve 218 of the spin element 204 such that it may freely slide without encountering any signi.ficant resistance.

The head section 224 has a through bore 227 arranged at the center thereof and a radial groove 229 arranged at a top 228 thereof.

The sleeve section 215 of the outer member 222 has a radial window hole 230 corresponding to the radial groove 229 arranged in the head section 224 of the inner member 223.

On the other hand. a guide sleeve 231 extending from the valve seat 208 of the nozzle head 202 toward the upstream side of the liquid flow paths also has a radial window hole 232 corresponding to the radial window hole 230.

corresponding to the radial window hole 230.

With the above described arrangement, the .Lquid f low path 233 of the discharge pipe F is held in communication with the annular groove 222B arranged in front of the pressure bearing surface 214 of the pressure bearing sleeve 211 of the outer member 222 via the port 234 of the spin element 204, the Iliquid flow path 209. the inner space 226A of the slide sleeve 226 of the inner member .223, the through bore 227, the groove 229 and the window holes 230 and 232.

In the above described second embodiment, the valve body 210 is pressed against the valve seat 208 by liquid pressure applied to the horizontal projection surface area of the inner member 223 facing the liquid flow path 209 and by the resi.1i.ent force of t:he spring member 213. The outer member 222 is pressed toward the upstream side of the liquid flow paths under li.quid pressure in the liquid flow path 209, which pressure is applied to the horizontal projecti on surface area of the pressure hear ing surface 214 of the pressure bearing sleeve 211 of the outer member 222.

An appropriate value for the horizontal projection surface area of the pressure bearing surface 214 is selected such that the component of the force generated by the proper liquid discharge pressure applied to said horizontal projection surface area of the pressure bearing surface 214 is greater than the sum of the force generated by the proper liquid discharge pressure applied to the horizontal surface area of the inner member 223 facing the liquid flow path 209 and the resilient force of the spring member 213. When the liquid pressure reaches the level of the proper liquid discharge pressure, the valve body 210 is moved from the valve seat 208 and opened under liquid pressure to make the liquid flow path 209 communicate with the liquid flow path 207 arranged downstream relative to the valve seat 208 as shown in Fig. 15 so that liquid is discharged through the discharge aperture 205 of the nozzle tip 206.

When the liquid pressure falls under the proper liquid discharge pressure, the valve body 210 is closed to completely stop any discharge of liquid so that liquid can be effectively prevented from dripping out as in the case of the first embodiment.

In the second embodiment as described above, the inner member 223 is press-fit into the outer member 222 that is provided with a liquid guide 203 having a valve body 2.10, and the opening of the slide sleeve 226 of the inner member 223 faces vis-a-vis the liquid flow path 209. Thus, the hori zon tal projection surface area of the slide sleeve 226 as indicated by arrow S in Figs. 9 and 15 can be made very small relative to the corresponding surface area of the first embodiment, so as to ncrease the ratio of said horizontal projection surface area of t.

S the slide sleeve 226 to the horizontal projection surface area of the pressure bearing surface 214 of the pressure bearing sleeve 211.

This means that the initial priming operation for eliminating air in the liquid cylinder and drawing up liquid through the cylinder by reciprocating the piston can be carried out in a short period of time.

Additionally, since the valve body 210 of the second embodiment can be opened simply by using pneumatic pressure in the initial priming operation, the discharge valve 111 as shown in Fig. 33 can be omitted.

Figs. 16 through 19 show, in enlarged longitudinal cross section, the pump unit of a further embodiment of liquid discharge device. The pump unit 22 comprises a cylinder 23 and a piston 24.

The cylinder 23 comprises an outer sleeve 25 designed to cooperate with a piston 24, and an inner sleeve 27 in which a spring 26 is arranged to urge the piston 24 to move back to the retracted position.

A cylinder chamber 28 is formed between the outer sleeve and the inner sleeve 27 and held in communication with a liquid flow path 110 provided with a ball valve 120 (which operates as a check valve) by way of a liquid intake/discharge port 30 bored through a bottom wall 29 the cylinder chamber 28.

An inner per ipheral wall 31 of the outer sleeve 25 is provided with a plurality of short and shallow grooves 32 running longitudinally near the bottom wall 29.

While the illustrated short and shallow grooves 32 are arranged on the inner peripheral wall 31, pairs of short and .ow ridges may alternatively be formed longitudinally such that the interval separating each pair of ridges functions as a short groove and shallow groove.

The outer sleeve 25 is additionally provided at a position near the bottom wall 29 with an air intake port 123 for drawing out air into the container to which the trigger type liquid di scha rge d ev ice is fitted. Also a aa position closer to the opening 129 of the outer sleeve 25 than the air intake port 123, the outer sleeve 25 is provided with a plurality of shallow outer air feeding grooves 33 running longitudinally.

Note that, in the illustrated embodiment, the sha!llow grooves 32 are short in the longi tud inal[ direct ion but rather wide in the peripheral direction.

A stroke end side end portion of the piston 24 located clIose to the bottom wall 29 of the cylinder 23 has a rather thick wall portion, which is provided at the inner and outer periLpheries with respective resilient annular skirts 35 and 36 extending toward the stroke end side to closely contact with the~ inner peripheral wall 31 of the outer sle~eve 25 and the ou ter peripheral wall 34 o~f the inner sleeve 27 respectively.

The thick wall portion is additionally provided on the approach end side peripheral edge thereof with an annular skiLrt 37 extending toward the approach end side to closely contact with the inner peripheral wall 31 of the outer sleeve The interval separating the resilient annular skirts 85 and 37 is so selected that, as seen from Fig. 19, when the annular skirt 85 rides on the short and shalllow grooves 32 the annular skirt 37 closely contact with the inner peripheral wall 31 of the outer sleeve 25 at an edge portion 88 of the air intake port 1283 located close to the opening 129 of the outer sleeve An interval between the shallow outer air feeding grooves 883 *and the air intake port 123 is so selected that, as seen from Fig. 16, when the piston 24 takes the approach end position, th e shallow outer air feeding grooves 33 and the air intake port 12:3 are closed by the annular skirts 35 and 37, whereas, when the piston 24 is in the compression stroke, the annular skirt 37 rides on the shallow outer air feeding grooves 33 as shown i.n Fig. 17 and outer air is fed into the container via the air intake port 123 as shown by arrow P in Fig. 17, while the communication between the shallow outer air feeding grooves 33 and the air intake port 123 is blocked by the annular skirt 37 before the end of the compression stroke.

When the annular skirt 35 rides on the short and shallow groove 32 at the end of the compression stroke, the annular skirt closely contacts with the portions 31A of the inner peripheral wall 31 adjacent to the respective short and shallow grooves 32 but does not falls into the grooves 32. Thus, the li quid remaining in the remaining portion 28a of the cylinder chamber 28 and remaining in the liquid flow paths between the port 30 and the discharge aperture 118 (illustrated in Fig. 33) returns into the container under its own pressure by way of the short and shallow grooves 32, the gap 31B between the annular skirt :35 and the annular skirt 37 and the air intake port 123, so that any residual pressure would not affect the discharge aperture 118 and no liquid would drip out therethrough after the end of a discharging cycle.

Figs. 20 and 21 show a further embodiment of trigger type liquid discharge device which is of the general type shown in Figs.

16 to 19, having a similar configuration except the following.

Namely, according to the embodiment of Figs. 16 to 19, the outer sleeve 25 of the cylinder 23 has a single inner diameter. On the other hand, according to this embodiment, an outer sleeve of the cylinder comprises a large diameter outer sleeve section 39 *9 e located on the approach end side and a smaller di ameter ojter sleeve section 40 located on the stroke en(J side, said two outer sleeve sections being linked together by a connecting walL section 41 provided with an air intake port 42 that communicates with the inside of the container.

Additionally, according to the embodiment of Figs. 16 to 19, the piston 24 is realised as a one-piece component. On the other hand, according to this embodiment, the piston comprises two components, in other words, an air piston 4:3 slidably movable in the larger diameter outer sleeve section :39 and a liquid piston 44 fitted in the air piston 43 and sldably movable in t he smaller diameter outer sleeve section 40, said air piston 4:1 and said liquid piston 44 being connected with each other at- a top engaging portion The air piston 43 is provided. with grooves 43A on an inner peripheral surface thereof at the engaging portion In the i. LlLus trated embodiment, four grooves 43A are mtlually displaced by an angle or 90: on the inner peripheral surface of the air piston 4:3.

The liquid piston 44 has a top 44A thereof which is provided with a small hole 44B.

The small hole 44B communicates with the grooves 43A so that consequently an inner space 44C of the liquid piston 44. the inner space 27A of the inner sleeve 27 of the cylinder, the gap 27C between the outer peripheral surface 27B of the inner sleeve 27 and the inner peripheral surface 44D of the liquid piston 44, an inner space 43B of the air piston 43 and the air intake port 42 are held in communication with one another.

f. P:\OPER\GCP\37540.DIV 24/6/99 21 The larger diameter outer sleeve section 39 is provided on the inner peripheral surface thereof with a shallow outer air feeding groove 46. The cylinder is provided at an outer peripheral surface 27B located adjacent to a bottom wall 27D thereof with a short and shallow groove 48 for removing residual pressure.

The interval between the annular skirt 49 of the air piston 43 and the annular skirt 50 of the liquid piston 44 is the same as its counterpart of the embodiment of Figs. 16 to 19. Also, the functions of the outer air feeding groove 46, the short and shallow groove 48 and the annular skirts 49 and 50 are the same as their counterparts of Figs. 16 to 19.

Thus, as illustrated in Fig. 21, once the liquid piston 44 gets to the stroke end, the residual pressure in the cylinder chamber 28 is drawn back into the container by way of the above listed spaces and gaps as indicated by arrow Q and then through the air intake port 42.

Fig. 22 shows a still further embodiment of liquid discharge device. According to the embodiment illustrated in 20 Figs. 20 and 21, the air piston 43 and the liquid piston 44 are linked together at the top engaging portion 45. On the other hand, according to this embodiment, a liquid piston 51 is formed the top thereof with a transversal groove 105 for bearing the pushing member 103 of the trigger 102. The air piston 52 has a fitting sleeve 53 which is secured to a wall 54 of the liquid "piston 51 by means of undercuts In this embodiment, the cylinder comprises a large diameter outer sleeve section 39, a small diameter outer sleeve section *40 and an air intake port 42 arranged at a connecting wall section 41 which links the large diameter outer sleeve section 39 and the small diameter outer sleeve section 40, as in the case of the embodiment shown in Figs. 20 and 21.

The large diameter outer sleeve section 39 is provided on an inner peripheral surface thereof with a shallow outer air feeding groove 46.

SP:\OPER\GCP\37540.DIV 24/6/99 22 This embodiment differs from the above described embodiment of Figs. 20 and 21 in that the small diameter outer sleeve section 40 is provided on the inner peripheral surface 47 thereof with a short and shallow groove 48A for removing residual pressure.

In this embodiment, once the annular skirt 50A of the liquid piston 51 rides on the short and shallow groove 48A, the residual pressure in the cylinder chamber 28 is drawn back into the container by way of the gap between the inner peripheral surface 47 of the small diameter outer sleeve section 40 and the outer peripheral surface 51A of the liquid piston 51 as indicated by arrow R and then through the air intake port 42.

Fig. 23 show a further embodiment of the liquid discharge device. The liquid discharge device comprises a piston section 56 having an inwardly disposed liquid piston 57 and an outwardly disposed air piston 58 integrally formed with the inwardly disposed liquid piston 57. Said liquid piston 57 and said air piston 58 are provided with annular skirts 59, 60 and 61 directed toward the stroke end side. The air piston 58 is held 20 in close contact with an inner wall surface 64 of a large diameter outer sleeve section 63 of the cylinder 62. The liquid S-piston 57 is held in close contact with an inner wall surface 66 of a small diameter inner sleeve section 65 of the cylinder 62.

In this embodiment, the large diameter outer sleeve section 63 is not provided with a shallow groove for introducing outer air on the inner wall surface 64 thereof so that outer air is directly introduced into the container.

Note that a short pipe 68 is suspended downward from the air intake port 123 at a position close to the cylinder bottom wall 67.

.The short pipe 68 is so designed that residual liquid expelled from a short and shallow groove 69 arranged on an inner wall surface 66 of the small diameter inner sleeve section for removing residual pressure falls vertically into the container through gaps between the inner and outer peripheral P:\OPER\GCP\37540.DIV- 24/6/99 23 surfaces of the small diameter inner sleeve section 65, the outer peripheral surface of the liquid piston 57 and the inner peripheral surface of the air piston 58.

With this arrangement, once the annular skirt 60 rides on the short and shallow groove 69, the annular skirt 59 closes the air intake port 123 as it is moved to the position indicated by V in Fig. 23.

Figs. 24 and 25 show a further embodiment wherein an inner peripheral wall of a cylinder 72 of a pump unit 71 is divided into a large diameter section 73 located on the open end side and a small diameter section 75 located on the side of the bottom wall 74. An annular skirt 77 is formed on the 0.

*0 ee

S

g* to stroke end side of a piston 76 to resiliently abut the small diameter section 75 of the cylinder 72. An another annular skirt 78 is formed on the approach end side of the piston 76 to resiliently abut the large diameter section 73 of the cylinder 72.

A short and shallow groove 79 is peripherally, arranged on the cylinder 72 at a position where the small diameter section of the cylinder 72 is connected to the bottom wall 74. As seen from Fig. 25, the entire length of the small diameter section is so selected that, when the piston 76 gets to the stroke end and an edge of the annular skirt 77 gets into the short and shallow groove 79, the edge of the other annular skirt 78 is located on a boundary 80 of the large diameter section 7:3 and the small diameter section A liquid flow path 81 is formed in the small diameter section 75 at a position close to sai d boundary 80 and communicates with the inside of the container. An air intake port 82 is formed in the large diameter section 73 at a position close to said boundary In Figs. 24 and 25, reference numeral 83 denotes a liquid intake/discharge port.

A plurality of low projec:t ing r idges 84 are formed longitudinally on the inner peripheral wall of the large diameter section 73 of the cylinder 72 in a position slightly closer to the bottom wall 74 than the peripheral position occupied by the annular skirt 78 when the piston 76 gets to the approach end as shown in Fig. 24.

In this embodiment, when the piston 76 is moved from the approach end position shown in Fig. 24 to the stroke end position shown in Fig. 25, the liquid contained in a cylinder chamber is compressed and flows through a port 8:3 into a liquid flow path 86 to a lisquid flow path 87, because the annu lar skirt 77 moves along the inner peripheral wall of the small diameter sec tion When the peripheral edge of the aninular skirt 77 gets into a short and shallow groove 79 at the stroke end, any residual pressure that may exist within the piston 76b and in the liquid flow path 86 etc. is discharged to the container through the liquid flow path 81 and the gap between the short and shallow groove 79 and the annular skirt 77 to remove and possible cause of dripping of liquid.

Since the annular skirt 78 is located on the boundary 80 to open the air intake port 82 unide r this condition ail.r flows into: the container from the atmosphere to prevent any negative pressure from taking place wi thin the con tainer.

As the piston 76 is moved back by the resiliency of a spring 88, negative pressure is generated in the cylinder chamber 85 so that a check valve 89 is opened by the liquid, which is then sucked into the chamber 85 through liquid flow path 86 and the port 83.

As the piston 76 moves back, the annullar skirt 78 runs onto the low projecting grooves 84 to make the air intake port 82 communicate with the atmosphere so) as to prevent any negative pressure from taking place within the container. When the piston 76 gets to the approach end, the annular skirt 78 closely Y contacts with the inner peripheral wall of the large diameter section 73 to prevent the liquid from leaking out through the air intake port 82.

It may be needless to say that said short and shallow groove 79 may be replaced by a low projecting groove running longitudinally, and the low projecting ridges 84 may be replaced by short and shallow grooves running longitudinally.

The low projecting ridges 84 may be replaced by shallow outer air feeding grooves 33 illustrated in Fig. 16 or by a boundary 503 illustrated in Fig. 31.

Figs. 26 and 27 show a further embodiment of the liquid discharge device. 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 92 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 Fig. 27, 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 Fig. 27, 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 liqu.id 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 proj ec(t i ng ridge runni ng longitudinally.

Figs. 28 and 29 illustrate a further embodiment of the liquid discharge device. A cylinder 310 of a pump unit 310 is provided in a bottom wall 311 thereof with an coaxial sleeve 314 for receiving a spring 313 for urging back a pi.ston 312. At a posit on on an outer surface of the bottom wall 311 and facing a liqu id 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 center of its bottom wall 320 with a hole 321 communicating said liquid flow path 319.

The 1 quid guide pipe 317 is provided in ts 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 i.s sandwiched by the liquid guide pipe 317, an outer surface of the bottom wall 311 and the 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 whi(ch resiliently abut the inner peripheral surface of the cylinder 310. The piston 312 has a pin body 330 arranged at the axial center 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 Fig. 29 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 3:30, any residual pressure that may SP:\OPER\GCP\37540.DIV -24/6/99 29 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.

Fig. 30 is an enlarged longitudinal sectional view of a nozzle head section 401 according to the invention. The nozzle head section 401 comprises a nozzle head 402, a liquid guide 403, a spin element 404 and a nozzle tip 406 having a discharge aperture 405.

Said nozzle head 402 is provided with a valve seat 408 arranged in a liquid flow path 407 at a position upstream, as in 20 some of the embodiments described above. The liquid flow path 407 communicates with a liquid flow path 115 of the discharge pipe unit F through a liquid flow path 409, as in some of the embodiments described above.

Said liquid guide 403 has a valve body 410 and a pressure 25 receiving sleeve 411 integrally formed with the valve body 410.

The valve body 410 abuts on the valve seat 408 to close the liquid flow path 407. The pressure receiving sleeve 411 has a e• pressure bearing surface 414 which is arranged to face the upstream side of the liquid flow path 407 for bearing the liquid pressure.

Said liquid guide 40:3 has a guide sleeve 417 which is inserted into an inside of a guide sleeve 418 of the spin element 404. A coil spring 413 is provided in the compressod state between a spring seat 412 provided on the the guide sleeve 418 and a rear side of the valve body 410. The coil spring 413 presses the valve body 410 to the valve seat 408.

In Fig. 30, the reference numeral 419 denotes a longitudinal projection for supporting the coil spring, which projection is provided in the inside of the gu ide sleeve 417 of the liquid guide 403.

By operating the trigger, the liquid pressed to the flow path 115 flows through the liquid flow path 409 into the inside of the guide sleeve 417 of the liquid guide 403, and then flows between the longitudinal projections 419 and through an opening 420. Thus, the liquid pressure presses a pressure bearing surface 414 of the pressure receiving sleeve 411.

When the force generated by the liquid pressure which is applied to the pressure bearing surface 414 is greater the force generated by both the resilient force of the spring member 413 and the force of the liquid pressure which is applied to the rear surface of the valve body 410, the valve 410 opens. In this embodiment, since the coil spring 413 is not integrally formed, it is very easy to form the liquid guide 403.

Fig. 31 illustrates a further embodiment of the liquid discharge device. In the embodiment illustrated in Fig. 16, a P:\OPER\GCP\37540.DIV -24/6199 31 plurality of shallow outer air feeding groove 33 are depressedly and longitudinally formed on the inner surface of the outer sleeve 25 of the cylinder 23. On the other hand, in the embodiment illustrated in Fig. 31, the outer cylinder 25 has the inner surface which comprises an inner surface 502 at the opening 129 side and an inner surface 501 provided at an area where the resilient annular skirts 35, 36, 37 moves upon a liquid discharge phase. The inner surface 502 has a diameter slightly larger than a diameter of the inner surface 501. A boundary 503 of the diameter between the inner surface 502 and the inner surface 501 has a wave shape as illustrated by a dotted line in Fig. 31. When the annular skirt 37 reaches to the wave-shaped boundary 503, outer air is introduced through the opening 129 to the air intake port 123.

This embodiment has a construction the same as that of the embodiment illustrated in Fig. 16 except the constructions of the above described wave-shaped boundary 503 and a liquid flow sleeve 505 having a check valve 504.

S. According to this embodiment it is easy to remove the 20 cylinder 23 from a metal mold.

the above described embodiments, some have pistons that S.are configured to allow easier retrieval from the mold to .oo.

improve their productivity if compared with the embodiment of Fig. 16, because the piston is constituted of an air piston and 25 a liquid piston and additionally the annular skirts of the piston are directed in the same direction in one of these embodiments.

Fig. 32 shows, in enlarged cross section, a principal area of a trigger type liquid discharge device according to the invention. As shown, the trigger type liquid discharge device has a single nozzle head section 70 comprising a nozzle head 2, a liquid guide 3, a spin element 4 and a nozzle tip 6 the same as those of a liquid discharge device according to the embodiment illustrated in Figs. 1 through 8, while it also has a pump unit 71 comprising cylinder members 39, 40, 41 and 42 and P, rAhsb\2190512res dc- 13/02/02 -32piston members 43, 44, 46, 48, 49 and 50 the same as those of a liquid discharge device according to the embodiments illustrated in Figs. 20 and 21. With this arrangement, again, undesired liquid and bubbles can be effectively prevented from dripping out of the discharge aperture Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

o e i o a o a** a a

Claims (6)

1. 2. A trigger type liquid discharge device comprising a oo 30 container, a pump unit having a cylinder and a piston, a discharge pipe 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 said cylinder of the pump unit comprises an outer sleeve and an inner sleeve concentrically within the outer F 2:rh 190512resd- 13/0202 -34- sleeve, a short and shallow groove is circumferentially provided on an outer surface of the inner sleeve at a position adjacent to a bottom wall of the outer sleeve, and said piston is provided with a skirt which closely contacts with the outer surface of the inner sleeve, and is so arranged that when the skirt is positioned in the short and shallow groove, a liquid flow path communicates with the inside of the container through a gap between the skirt and the short and shallow groove, a port in the rear of the piston, grooves formed in an inner surface of an outer sleeve of the piston and an intake port of the outer sleeve of said cylinder.
2. 3. A trigger type liquid discharge device comprising a container, a pump unit having a cylinder and a piston, a discharge pipe having a discharge aperture, and a trigger for reciprocating the piston, wherein liquid drawn up from the container is discharged through the discharge aperture 20 by movement of the piston to a stroke end, wherein said cylinder of the pump unit comprises an outer sleeve and an inner sleeve concentrically within the outer sleeve, S"a bottom wall of an inner sleeve of the cylinder is formed with a hole therein, said hole communicating to an ~i upper end of a liquid flow path, said liquid flow path communicating to the container, .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, an annular skirt of the piston is inserted into the short and shallow groove upon the stroke end, so that said liquid flow path communicates to the inside of the container through a gap between the skirt and the short and shallow groove, a port in the rear of the cylinder and through an intake port of the outer sleeve. P..i'r/bh'2 19051 -A-d 3102/02
3. 4. The trigger type liquid discharge device according to claim 1, wherein a liquid guide is arranged in a liquid flow path disposed upstream relative to the discharge aperture, said liquid guide comprising a valve body for closing the liquid flow path, a pressure bearing sleeve formed integrally with the valve body, a first guide sleeve connecting the valve body and the pressure bearing sleeve through an opening, the first guide sleeve of the liquid guide is slidably inserted into the inside of a guide sleeve of a spin element, the valve body is urged by a spring provided in a compressed state between a spring seat provided on the first guide sleeve and a rear side of the valve body to close the liquid flow path, and the pressure bearing sleeve has a pressure bearing surface facing the upstream side of the liquid flow path for bearing the liquid pressure, an area of said pressure bearing surface is so selected that a force generated by a proper liquid discharge pressure that is applied to said pressure bearing surface is greater oo* V:-.00 than the sum of a resilient force of the spring member and a S.force applied to the pressure bearing surface and directed o: 25 to the downstream side of the liquid flow path. The trigger type liquid discharge device according to claim 2, wherein a liquid guide is arranged in a liquid flow path disposed upstream relative to the discharge aperture, said liquid guide comprising a valve body for closing the liquid flow path, a pressure bearing sleeve formed integrally with the valve body, an anchor member to be secured to the discharge pipe, and a spring member for coupling said integrally formed valve body and the pressure bearing sleeve with the anchoring member, P:perk hS2h 1905 I2r.dc- 3102/02 -36 said pressure bearing sleeve has a pressure bearing surface facing the upstream side of the liquid flow path for bearing the liquid pressure, an area of said pressure bearing surface is so selected that a force generated by a proper liquid discharge pressure that is applied to said pressure bearing surface is greater than the sum of a resilient force of the spring member and a force applied to the valve body and directed to the downstream side of the liquid flow path.
4. 6. The trigger type liquid discharge device according to claim 2, wherein a liquid guide is arranged in a liquid flow path disposed upstream relative to the discharge aperture, said liquid guide comprising a valve body for closing the liquid flow path, a pressure bearing sleeve formed integrally with the valve body, a first guide sleeve connecting the valve body and the pressure bearing sleeve through an opening, ::the first guide sleeve of the liquid guide is slidably 20 inserted into the inside of a guide sleeve of a spin *.e element, the valve body is urged by a spring provided in a *...compressed state between a spring seat provided on the first S"guide sleeve and a rear side of the valve body to close the liquid flow path, i the pressure bearing sleeve has a pressure bearing 0.0.*surface facing the upstream side of the liquid flow path for bearing the liquid pressure, and an area of said pressure bearing surface is so selected that a force generated by a proper liquid discharge pressure that is applied to said pressure bearing surface is greater than the sum of a resilient force of the spring member and a force applied to the pressure bearing surface and directed to the downstream side of the liquid flow path.
5. 7. The trigger type liquid discharge device according to P.N Vr\h 2190512rCS do- 13/0202 -37- claim 3, wherein a liquid guide is arranged in a liquid flow path disposed upstream relative to the discharge aperture, said liquid guide comprising a valve body for closing the liquid flow path, a pressure bearing sleeve formed integrally with the valve body, an anchor member to be secured to the discharge pipe, and a spring member for coupling said integrally formed valve body and the pressure bearing sleeve with the anchoring member, said pressure bearing sleeve has a pressure bearing surface facing the upstream side of the liquid flow path for bearing the liquid pressure, an area of said pressure bearing surface is so selected that a force generated by a proper liquid discharge pressure that is applied to said pressure bearing surface is greater than the sum of a resilient force of the spring member and a force applied to the valve body and directed to the downstream side of the liquid flow path. 20 8. The trigger type liquid discharge device according to claim 3, wherein ee a liquid guide is arranged in a liquid flow path disposed upstream relative to the discharge aperture, said liquid guide comprising a valve body for closing the liquid flow path, a pressure bearing sleeve formed integrally with the valve body, a first guide sleeve connecting to the valve body and the pressure bearing sleeve through an opening, the first guide sleeve of the liquid guide is slidably inserted into the inside of a guide sleeve of a spin 30 element, the valve body is urged by a spring provided in a compressed state between a spring seat provided on the first guide sleeve and a rear side of the valve body to close the liquid flow path, and 5 said pressure bearing sleeve has a pressure bearing surface facing the upstream side of the liquid flow path for P:\oper\sb2 19)0512r-s doc-14/10202 -38- bearing the liquid pressure, and an area of said pressure bearing surface is so selected that a force generated by a proper liquid discharge pressure that is applied to said pressure bearing surface is greater than the sum of a resilient force of the spring member and a force applied to the pressure bearing surface and directed to the downstream side of the liquid flow path.
6. 9. A trigger type liquid discharge device substantially as hereinbefore described with reference to the accompanying drawings. DATED this 1 4 th day of February, 2002 Yoshino Kogyosho Co., Ltd. b *by DAVIES COLLISON CAVE 20 Patent Attorneys for the Applicant .0 0*