Note: Descriptions are shown in the official language in which they were submitted.
2179888
S P E C I F I C A T I O N
TRIGGER TYPE LIQUID DISCHARGE DEVICE
Field of the Invention
'I'tiis i.nverition 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 th.e liquid.
Prior Art
Fig. 33 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 P as
illustrated in Fig. 33.
The trigger type liquid discharge device as illustrated in
Fig. 33 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 V. a pushing member 103 by turn
depresses a transversal groove 105 of a head 104 of piston unit U
of the device so as to move a piston I until an end face 106 of
the piston 1 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 111
under its pressure.
1
2179888
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
an 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 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 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 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 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 floiv
through a suction pipe 122, the liquid flow patti 110 and the port
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 wa]].
2
2179888
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 ttie cylinder H and an
approach end side 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 1 is
located at an approach end position as indicated in Fig. 33, ttie
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 US
Patent No. 4,819,8:35 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 Fig. 33, reference symbol N denotes a cap for covering
3
2179888
= 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 LJS Patent No. 4,819,835 operates satisfactorily efficiently
for discharging liquid, it is accompanied by certain draivbacks
particularly in terms of the pressure of t.he liquid i'lowing froin
the cylinder chamber 108 to the discharge aperture 118 during
liquid discharging operation. More specifically, referring to
Fig. 34, during time TS from when the piston 1 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.
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 in Fig. 33 and improved such
that no liquid drips out through the discharge aperture of the
4
CA 02179888 2004-06-04
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 one aspect of the present invention, a trigger type
liquid discharge is provided wherein a valve structure is arranged on
the upstream side of the discharge aperture that is opened exactly when
the internal liquid pressure gets to a predetermined discharge pressure
so as to prevent any discharge of the liquid through the discharge
aperture until the internal liquid pressure gets to the predetermined
discharge pressure.
According to a further aspect of the present invention, a trigger type
liquid discharge device is provided wherein a liquid pressure relief
mechanism which returns any residual liquid pressure in the liquid flow
path to the liquid container is provided on the pump unit of the device for
pumping up liquid from the container to the liquid discharge device, so as
to prevent liquid from dripping out in the initial and final stages of liquid
discharging operation.
According to another aspect of the present invention, a trigger type
liquid discharge device is provided having a valve structure on the
upstream side of the discharge aperture and a liquid pressure relief
mechanism on the pump unit of the device wherein the valve structure
opens exactly when the internal liquid pressure gets to a predetermined
discharge pressure and wherein the liquid pressure relief mechanism
returns any residual liquid pressure in the liquid flow path to the liquid
container to prevent liquid from dripping out in the initial and final stages
of liquid discharging operation.
CA 02179888 2004-06-04
According to yet another aspect of the present invention, the trigger
type liquid discharge device is constructed such that it is prevented to
excessively decrease the pressure in the container due to the reciprocation of
the pump mechanism.
According to still another aspect of the present invention, the trigger
type liquid discharge device is improved so that it is easy to form the valve
construction.
According to a further aspect of the present invention, a trigger type
liquid discharge device is provided wherein the residual pressure in the
area from the liquid flow path to pump mechanism can be removed by
using the outer surface of the inner sleeve which receives the spring and is
arranged in the cylinder of the pump mechanism.
According to another aspect of the present invention, a trigger type
liquid discharge device is provided 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
suck the air.
According to yet another aspect of the present invention, a trigger type
liquid discharge device is provided wherein the tolerance of the cylinder and
the pist;on etc. of the pump mechanism does not affect the remove of the
residual pressure from the pump .mechanism.
According to still another aspect of the present invention, a trigger
type liquid discharge device for the use condition is provided by
combining the valve construction and the pump mechanism as
6
CA 02179888 2004-06-09
describe above.
According to one aspect of 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 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 liquid
guide
is arranged in a liquid flow path disposed upstream relative to the discharge
aperture,
the 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 for coupling the integrally formed
valve
body and the pressure bearing sleeve with the anchor member, wherein the
pressure
bearing sleeve has a pressure bearing surface facing the upstream side of the
liquid
flow path for bearing the liquid pressure, and wherein an area of the pressure
bearing
surface is so selected that a force generated by a proper liquid discharge
pressure that
is applied to the pressure bearing surface is greater than a sum of a
resilient force of
the spring and a force applied to the valve body and directed to the
downstream side
of the liquid flow path.
According to a further aspect of 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 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 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, the 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, the
piston is
formed with a pair of annular skirts held in close contact with the inner
peripheral
wall of the cylinder, and a gap separating the pair of annular skirts is so
selected that,
when one of the annular skirts rides on the short and shallow grooves of the
cylinder,
the other of the annular skirts is brought into close contact with inner
peripheral wall
of the cylinder at a position closer to an open edge of the cylinder than the
air intake
port.
7
CA 02179888 2004-06-09
According to another aspect of 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 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
liquid guide is arranged in a liquid flow path disposed upstream relative to
the
discharge aperture, the 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 for coupling the
integrally
formed valve body and the pressure bearing sleeve with the anchor member,
wherein
the pressure bearing sleeve has a pressure bearing surface facing the upstream
side of
the liquid flow path for bearing the liquid pressure, wherein an area of the
pressure
bearing surface is so selected that a force generated by a proper liquid
discharge
pressure that is applied to the pressure bearing surface is greater than a sum
of a
resilient force of the spring and a force applied to the valve body and
directed to the
downstream side of the liquid flow path, 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, the short and shallow grooves
running
longitudinally, wherein the inner peripheral wall of the cylinder is provided
with an
air intake port communicating with an inside of the container, wherein the
piston is
formed with a pair of annular skirts held in close contact with the inner
peripheral
wall of the cylinder, and wherein a gap separating the pair of annular skirts
is so
selected that, when one of the annular skirts rides on the short and shallow
grooves of
the cylinder, the other of the annular skirts is brought into close contact
with inner
peripheral wall of the cylinder at a position closer to an open edge of the
cylinder than
the air intake port.
According to still another aspect of 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 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
liquid guide is arranged in a liquid flow path disposed upstream relative to
the
7a
CA 02179888 2004-06-09
discharge aperture, the liquid guide comprising a valve body for closing the
liquid
flow path, a pressure bearing sleeve formed integrally with the valve body,
and guide
sleeve connecting the valve body and the pressure bearing sleeve through an
opening,
wherein the guide sleeve of the liquid guide is inserted into the inside of a
guide
sleeve of a spin element, wherein the valve body is urged by a spring between
the
guide sleeve and a second guide sleeve to close the liquid flow path, wherein
the
pressure bearing sleeve has a pressure bearing surface facing the upstream
side of the
liquid flow path for bearing the liquid pressure, and wherein an area of the
pressure
bearing surface is so selected that a force generated by a proper liquid
discharge
pressure that is applied to the pressure bearing surface is greater than a sum
of a
resilient force of the spring and a force applied to the pressure bearing
surface and
directed to the downstream side of the liquid flow path.
According to a further aspect of 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 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 the
cylinder of the pump unit comprises an outer sleeve and an inner sleeve
concentrically with 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 the 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, the liquid flow path communicates
to the
inside of the container through a gap between the skirt and the short and
shallow
groove.
According to another aspect of 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 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 the
bottom wall of an inner sleeve of the cylinder is formed with a hole at a
center
7b
CA 02179888 2004-06-04
thereof, the hole communicating to an upper end of a liquid flow path, the
liquid flow
path communicating to the container, short and shallow groove is provided at a
boundary between an outer surface of the 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 second 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.
According to yet another aspect of 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 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 center of a bottom wall of the cylinder, the hole
communicates to a
liquid flow path which 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 of
the cylinder, and a pin body is provided at a center of the piston toward the
bottom
wall of the cylinder, and is so provided that when the piston reaches the
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 according to the invention
of the claim 1, 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.
7c
CA 02179888 2004-06-04
Fig. 4 is an enlarged lateral view of an integral structure
comprising a valve body a pressure bearing sleeve, an anchoring
member and a spring member as shown in Fig. 1.
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 80'
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.
Fig. 9 is an enlarged longitudinal sectional view of a
second embodiment of liquid discharge device according to the
invention of the claim 1, 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. 10.
7d
2179888
Fig. 12 is a lateral partially sectional view of the member
of Fig. 10, obtained by rotating it by 90' from the position of
Fig. 10.
Fig. 13 isan 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 first embodiment of liquid discharge device _
according to the Inventions of the claim 2 and the claim 4,
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.
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 second embodiment of liquid discharge device
according to the invention of the claim 6, showing the Inside
during an air intake phase.
Fig. 21 is an enlarged longitudinal sectional view of the
8
2179888
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 third embodiment of liquid discharge device
according to the invention, showing the inside during a residual
pressure relieving phase.
Fig. 23 is an enlarged longitudinal sectional view of' the
pump unit of a fourth embodiment of liquid discharge device
according to the invention, showing the inside during a liquid
discharge phase.
Fig. 24 is an enlarged longitudinal sectional view of a
fifth embodiment of pump mechanism according to the invention of
the claim 6, 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 the
pump mechanism according to the invention of the claim 7. 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.
Fig. 28 is an enlarged longitudinal sectional view of an
embodiment according to the invention of claim 8 and showing when
the piston gets to the approach end.
Fig. 29 is an enlarged longitudinal sectional view of tlie
embodiment of Fig. 28 showing the residual pressure clearing
stroke.
Fig. 30 is an enlarged longitudinal section view according
to the invention of the claim 5.
9
2179888
Fig. 31 is an enlarged longitudinal section view of an
another embodiment according to the invention of the claim 4.
Fig. 32 is an enlarged longitudinal sectional view of an
embodiment of the liquid discharge device according to the
invention of the claim 3, 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
operation of a trigger type liquid discharge device as shown in
Fig. 25.
TAE 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
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 nozzlehead
section 1 of a first embodiment of liquid discharge device
according to the claim 1. The nozzle head section 1 comprises a
nozzle head 2, a liquid guide 3, a spin el.eme.nt 4 and a nozzle
tip 6 having a discharge aperture 5.
The nozzle head 2 is provided with a valve seat 8 arranged
in a liquid flow path 7 at a position upstream relative to the
2179888
discharge aperture 5. Said liquid flow patti 7 communicates with
the liquid flow path 115 of the discharge pipe unit F via a
liquid flow path 9.
As shown in Figs. 4 through 7, said liquid guide :3 comprises
a valve body 10 which abuts on the valve seat 8 to close the
liquid fl.ow path 7, a pressure bearing~ sleeve 11 integra].ly
formed with the valve body 10, an anchoring member 12 to be
secured to the spin element 4 and a spring member 1:3 f'or 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 11
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 10 and the
pressure bearing sleeve 11 is coupled by means of a sleeve 15
provided with a window 16 which communicates to the liquid flow
path 9. As shown in Fig. 1, the pressure of the liquid is applied
to ttie 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 ttie valve seat 8, keeping its proper
posture. The anchoring member 12 and the spring member 1:3 are
arranged in an annular space 4C between the guide sleeve 18 and
il
2179888
an outer sleeve 4B of the spin element 4-
As seen from Figs. 1, 2, 3 and 8, ttie nozzle head 2 has a
recess 19 at the front end thereof for bearing and securing or
tiolding 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.
Referring to Fig. 1, the valve body 10 is pressed against
the valve seat 8 in Fig. 1 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, ttie force generated by the proper liquici
discharge pressure that is applied to said horizontal projection
surface area of the pressure bearing surface 14 is greater than
12
21l 88$
ttie 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 of the claim 1, the valve
body 10 is opened when the liquid pressure reaches the proper
liquid discharge pressure Y as shown i.n rig. 34 so that liquid is
discharged in the direction indicated by arrow Z in Fig. H. The
valve body is closed when the liquid pressure falls under the
proper liquid discharge pressure. With 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 shows, in an enlarged scale, the nozzle
head 201 of a second embodiment of liquid discharge device
according to the invention of the claim 1. 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 includirig 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
13
2179888
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 side liquid
fl.ow 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-fit 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 ttie inside of
guide sleeve 218 of the spin element 204 such that it may freely
slide without encountering any significant 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 ai-adial
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.
14
2179888
With the above described arrangement, the liquid flow 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 liquid
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 resilient force of the
spring member 213. The outer member 222 is pressed toward the
upstream side of the liquid flow paths under liquid pressure in
the liquid flow path 209, which pressure is applied to the
horizontal projection surface area of the pressure bearing
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 tiorizontal 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
2179888
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 210, and the
opening of the slide sleeve 226 of the inner member 223 faces
vis-a-vis the liquid flow path 209. Thus, the horizontal
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
increase the ratio of said horizontal projection surface area of
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
16
2179888
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 first embodiment of liquid discharge
device according to the invention of the claim 2. The pump unit
22 comprises a cylinder 23 and a piston 24.
The cylinder 23 comprises an outer sleeve 25 desigried to
cooperate with a piston 24, and an inner sleeve 27 irr 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 25
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 peripheral 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 low
ridges may alternatively be formed longitudinally sucti 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 1'223 f'or drawing
out air into the container to which the trigger type liqui.d
discharge device is fitted. Also, at a position closer to the
opening 129 of the outer sleeve 25 than the air intake port 123,
17
~ . 2179888
the outer sleeve 25 is provided with a plurality of shallow outer
air feeding grooves 33 running longitudinally.
Note that, in the illustrated embodiment, ttie shallow
grooves 32 are short in the longitudinal direction but rather
wide in the peripheral direction.
A stroke end side end portion of the~piston 24 located close
to the bottom wall 29 of the cylinder 23 has a rattier thick wall
portion, which is provided at the inner and outer peripheries
with respective resilient annular skirts 35 and 36 exterrding
toward the stroke end side to closely contact with the inner
peripheral wall 31 of the outer sleeve 25 and the outer
peripheral wall 34 of the inner sleeve 27 respectively.
The thick wall portion is additionally provided on the
approach end side peripheral edge thereof with an annular skirt
37 extending toward the approach end side to closely contact with
the inner peripheral wall 31 of the outer sleeve 25.
The interval separating the resilient annular skirts 35 and
37 is so selected that, as seen from Fig. 19, when the annular
skirt 35 rides on the short and shallow grooves 32, the annular
skirt 37 closely contact with the inner peripheral wall 31 of the
outer sleeve 25 at an edge portion 38 of the air intake port 123
located close to the opening 129 of the outer sleeve 25.
An interval between the shallow outer air feeding grooves 33
and the air intake port 123 is so selected that, as seen from
Fig. 16, when the piston 24 takes the approach end position, the
shallow outer air feeding grooves 33 and the air intake port 123
are closed by the annular skirts 35 and 37, wherears, when the
piston 24 is in the compression stroke, the annul.ar skirt 37
18
2179888
= rides on the shallow outer air feeding grooves 33 as shown in
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
35 closely contacts witki the portions 31A of the iriner peripheral
wall 31 adjacent to the respective short and shallow grooves 32
but does not falls into the grooves 32. Thus, the liquid
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 second embodiment of trigger type
liquid discharge device according to the claim 1, traving a
configuration similar to that of the first embodiment of Figs. 16
through 19 except the following.
Namely, according to the first embodiment, the outer sleeve
25 of the cylinder 23 has a single inner diameter. Orr the other
hand, according to the second embodiment, an outer sleeve of the
cylinder comprises a large diameter outer sleeve section 39
19
2179888
= located on the approach end side and a smaller diameter outer
sleeve section 40 located on the stroke end side. said two outer
sleeve sections being linked together by a connecti.rig wall
section 41 provided with an air intake port 42 that communicatcs
with the inside of the container.
Additionally, according to the first embodiment, the piston
24 is realized as a one-piece component. On the other hand,
according to the second embodiment, the piston comprises two
components, in other words, an air piston 43 slidably movable in
the larger diameter outer sleeve section 39 and a liquid piston
44 fitted in the air piston 43 and slidably movable in the
smaller diameter outer sleeve section 40, said air piston 43 and
said liquid piston 44 being connected with each other at a top
engaging portion 45.
The air piston 43 is provided with grooves 43A on an inner
peripheral surface thereof at the engaging portion 45.
In ttre illustrated embodiment, four grooves 43A are mutually
displaced by an angle of 90' on the inner peripheral surface of
the air piston 43.
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 ttce liquid piston 44, the
inner space 27A of the inner sleeve 27 of the cyli_nder. 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.
2179888
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 adjacentto a bottom wall 27ll
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 same as
its counterpart of the first embodiment. Also, the functions of
the outer air feeding groove 46, the short and shallow groove 48
and the annular skirts 49 and 50 are same as their counterparts
of the first embodiment.
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 ttirough
ttie air intake port 42.
Fig. 22 shows a third embodiment of liquid discharge device
according to the invention of the claim 2. According to the
second embodiment illustrated in 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 the third
embodiment, A liquid piston 51 is formed at the top thereof with
a transversal groove 105 for bearing the pushing member 103 of
the trigger 102. The air piston 522 has a fitting sleeve 53 which
is secured to a wall 54 of the liquid piston 51 by means of
undercuts 55.
In this embodiment, the cylinder comprises a large diameter
21
2177888
outer sleeve section 39, a small diameter outer sleeve section 40
and an air intakc port 42 arranged at a connecting wall section
41 which lirrks the the large diameter outer sleeve section 39 and
ttie small diameter outer sleeve section 40, as in the case of the
above described second embodiment
Ttie large diameter outer sleeve section 39 is provided on an
inner peripheral surface thereof with a shallow outer air feeding
groove 46.
This third embodiment differs from the above described
second embodiment in that the small diameter outer sleeve section
40 is provided ori 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 grove 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 shows a fourth embodiment of liquid discharge device
according to the invention of the claim 2. 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 errd side.
The air piston 58 is held in close contact with an inner wall
surface 64 of a large diameter outer sleeve section 6:3 of thc
22
~ 2'~i98~8
cylinder 62. The liquid 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,_ Instead, , 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 65 for
removing residual pressure falls vertically into the container
through gaps between ttie inner and outer peripheral surfaces of
the small diameter inner sleeve section 65, the outer peripheral
surface of the liquid piston 57 and tiie inner peripheral surface
of the air piston 58.
With this arrangement, once the annular skirt 60 rides on
ttie 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 an embodiment of the claim 6 in
addition to a-fifth embodiment of the invention of' claim 2,
wherein an inner peripheral wall of a cylinder 72 of a pump unit
71 is divided into a large diameter section 7:3 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
23
2179888
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 penipherally arranged on
the cylinder 72 at a position where the small diameter section 75
of the cylinder 72 is connected to the bottom wall 74. As seen
from Fig. 25, the entire length of the small diameter section 75
is so selected that, when the piston 76 gets to ttie stroke end
and an edge of the annular skirt 77 gets into the shor't and
shallow groove 79, the edge of the other annular skirt 78 is
located on a boundary 80 of the large diameter section 73 and the
small diameter section 75.
A liquid flow path 81 is formed in the small diameter
section 75 at a position close to said 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 80.
In Figs. 24 and 25, reference numeral 83 denotes a liquid
intake/discharge port.
A plurality -of low projecting ridges 84 are formed
longitudinally on the inner peripheral wall of ttie 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
24
2179888
approach end position shown in Fig. 24 to the stroke end position
shown in Fig. 25, the liquid contained in a cylinder chamber 85
is compressed and flows through a port 83 into a liquid i'low path
86 to a liquid flow path 87, because the annular skirt 77 moves
along the inner peripheral wall of the small diameter section 75.
When the peripheral edge of the annular skirt 77 gets into a
short and shallow groove 79 at the stroke end, any residual
pressure that may exist within the piston 761) 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 under this condition, air flows into
the container from the atmosphere to prevent any negative
pressure from taking place within the container.
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 annular 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. t1'hon the piston
76 gets to the approach end. the annular skirt 78 closely
contacts with the inner peripheral wall of the large di.ameter
section 73 to prevent the liquid from leaking out through the air
2179888
s = 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 an embodiment of the invention of claim
7. 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 an 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 shallon groove 301.
In order to allow air to enter the container from the
atmosphere, an air intake port 302 is formed on t.tie cylinder wall
in a position close to the open end of the cylinder than the
26
= 2179888
position of the annular skirt 95 when the piston 93 gets to ttie
stroke end.
In this embodiment, when the piston 93 gets to the stroke
end as shown in Fig. 27, the edge of the arnular 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 periphera]. 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.
Figs. 28 and 29 illustrate an embodiment of the invention of
claim 8. A cylinder 310 of a pump unit 310 is provided in a
27
2179888
bottom wall 311 thereof with an coaxial sleeve 31.4 f'or receiving
a spring 313 for urging back a piston 37.2. At a position on an
outer surface of the bottom wall 311 and facing a liquid guide
pipe 317 having a check valve :31:~ and a liyuid flow E>;it:h :31E, the
cylinder :310 is provided with a liquid f'Jow path :319
communicating with the inside of the csont:aincr. Said spri-ng
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 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 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 which
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 c:ondi.tion of' the
hole 321.
As the closed condition of the hole 321 is re.leased by the
front end 331 of the pin body 330, any residual pressure thal. may
28
2179888
exist in the liquid flow path 316, ttie c:ylinder 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.
According to the invention of claim~:3, since tlie residual
pressure is removed by positively causing thc 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 section view of a nozzle
head section 401 according the invention of the claim 5. 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
like the first and second embodiments. 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 like the first and
second embodiments.
Said liquid guide 403 has a valve body 410 and a pressure
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
29
2179888
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 403 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 compressed 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 guide sleeve 417 of the liquid
guide 403.
By operating ttte 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 tlirough 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 forc:e of the liquid pressure which is appl.i.ed to the rear
surface of ttte valve body 410, the valve 410 opens. lr this
embodiment, since the c.oil spring 413 is not, integrali.y Pormed,
it is very easy to form the liquid guide 403.
Fig. 31 illustrates an embodiment of the inventi,on of Lhe
claim 4. In the first embodiment illustrated in Fig. 16, a
~ 2179888
plurality of shallow outer air feeding groove 33 are depressedly
and longitudinally formed on the inner surface of tiie outer
sleeve 25 of the cylinder 23. On the other hand, in tttis
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 liquic3 discharge
phase. The inner surface 502 has a diameter slii;htly 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. R'hen
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 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.
According to this embodiment of the claim 4, it is easy to
remove the cylinder 23 from a metal mold.
Of the above described embodiments according to the Llhe
invention of the claim 2. the second and third ones have pistons
that are configured to allow easier retrieval from the mold to
improve their productivity if compared with the first ernbodiment,
because the piston is constituted of an air piston and a]iquid
piston in the case of the second and third embodirnent.s and
additionally the annular skirts oi' the piston are directed iti a
same direction in the case of the third embodiment.
:3 1
2179888
Fig. 32 shows, in enlarged cross sectiorr, a principal area
of a trigger type liquid discharge device according to the the
invention of the claim 3. As shown, ttre trigger type liquicl
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 same as those of a liquid discharge device according ito the
invention of the claim 1 and illustrated in Figs. 1 through 8,
while it also has a pump unit 71 comprising cylinder members :39,
40, 41 and 42 and piston members 43, 44. 46, 48, 49 arid 50 same
as those of a liquid discharge device according to the invention
of the claim 2 and 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
5.
:32
