Manual spray pump

A manual spray pump comprises a cylinder consisting of different diameter portions integral with one another and extending from one another and large and small pistons having respective collars of different diameters and fitted in respective cylinder portions in elastic contact with the inner wall thereof for reciprocal movement in the axial direction. The small piston is coupled to the large piston such as to receive liquid pressure therefrom, and a valve body provided at the top of the small piston co-operates with a valve seat of the large piston to constitute an opening valve. Further, in order to control or suppress too sensitive action of the small piston under low liquid pressure when actuating the opening valve with the liquid pressure exerted from the large piston to the small piston, the small piston is provided with an integral additional piston member of a still smaller diameter or is adapted to produce a frictional force in part of its portion coupled to the large piston. Still further, part of the cylinder wall is provided, at a position near the position of the end of downward stroke of either large or small piston, with an escapement hole for releasing the residual liquid pressure so as to be able to bring a sudden end to the spraying and eliminate spraying under low liquid pressure.

BACKGROUND OF THE INVENTION 
A well-known construction of spray pumps for spraying cosmetic liquid, 
insecticide, washing liquid and other home spray liquid has two pistons of 
different diameters and serially coupled to each other, that is, with the 
small piston coupled before the large piston. The large piston has a valve 
adapted to be closed in the direction of supplying liquid, while the small 
piston has a valve adapted to be opened only in the direction of supplying 
liquid. Further, the small piston is spring biased so that it is normally 
held at its dead point. 
Generally, the subject matter of these spray pumps have a number of times 
the discharge capacity of other well-known spray pumps of the same 
three-dimensional size. Also, they permit spraying of liquid under a high 
stored liquid pressure without the necessity of quickly or slowly 
depressing the pump piston with a finger, that is, irrespective of whether 
the piston is depressed with high or low finger pressure, thus permitting 
a finely atomized liquid spray pattern by a high pressure jet to be 
obtained. In case of the insecticide, these features can meet the 
requirement for the atomized liquid particles to float in space for a long 
period of time so as to obtain enhanced insecticidal effects. Also, in 
case of cosmetic liquid or the like they can be utilized as means for 
providing fine liquid particles which are required since it is desirable 
that the sprayed liquid quickly forms a thin film. 
Regarding the structure of the small piston in these spray pumps, the small 
piston is disposed below the large piston or concentrically disposed 
within the large piston or has other structures. In any case, it is 
arranged such as to receive liquid pressure increased by the large piston 
and be displaced by the received liquid pressure so as to open a valve 
which is normally closed in the direction of supplying liquid, thus 
permitting liquid under increased pressure to be sprayed from a nozzle 
button connected to the top of the cylinder. However, the small piston 
tends to be too sensitive to the liquid pressure received from the large 
piston, so that the valve of the small piston is liable to be actuated 
before the liquid pressure is sufficiently increased. In such case, the 
effect that can be provided by the subject liquid in this type of spray 
pump cannot be satisfactorily obtained. Besides, in these spray pumps the 
individual component parts are assembled within a small space, thus 
requiring high precision in manufacture. Further, the component parts are 
large in number and are complicated, so that the construction is readily 
prone to trouble. 
The spray pump according to the invention can control or suppress too 
sensitive action of the small piston without sacrifice in light and smooth 
operation and permits displacement of the small piston only under a 
sufficiently increased liquid pressure so that the effects which are to be 
provided by this type of spray pump to be obtained sufficiently and 
reliably. In addition, its construction is simplified by providing 
individual pistons of different diameters whithin a single cylinder 
consisting of different diameter portions. Further, a sudden end can be 
brought to spraying as soon as the last stage of downward stroke of piston 
is reached. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a spary pump, which comprises a 
cylinder having a valve adapted to be opened only in the direction of 
supplying liquid so as to provide for simple and reliable assembly of 
piston parts and also for steady operation, said cylinder including an 
upper large diameter cylinder portion and a lower small diameter cylinder 
portion integral with and extending from the large diameter cylinder 
portion, and if necessary a still smaller diameter cylinder portion 
integrally extending from the lower end of the small diameter cylinder 
portion, said cylinder accommodating a large piston and a small piston 
adapted to receive the liquid pressure from the large piston, said small 
piston being provided, if necessary, with a still smaller piston secured 
to the small piston, these pistons having their respective collars in 
elastic contact with the respective cylinder portions so that they are 
reciprocable in the cylinder in the axial direction thereof. 
Another object of the invention is to provide a spray pump, in which the 
small piston is provided with a still smaller piston integral therewith or 
has a portion in partial frictional contact with an associated portion of 
the large piston to produce additional friction force in order for the 
valve of the small piston closed in the direction of supplying liquid to 
be actuated only with a sufficiently increased stored pressure received 
from the large piston. 
A further object of the invention is to provide a spray pump, in which part 
of the cylinder wall is provided, at a position near the position of the 
end of downward stroke of either large or small piston, with an escapement 
hole for releasing the residual liquid pressure in relation to either 
piston as soon as the last stage of the downward stroke is reached, 
thereby interrupting the spraying of coarsely atomized liquid under 
reduced liquid pressure in the last stage of the downward stroke.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The spray pump according to the invention comprises a cylinder consisting 
of different diameter portions integral with one another and extending 
from one another and large and small pistons having respective collars of 
different diameters and fitted in respective cylinder portions in elastic 
contact with the inner wall thereof for reciprocal movement in the axial 
direction. The small piston is coupled to the large piston such as to 
receive liquid pressure therefrom, and a valve body provided at the top of 
the small piston co-operates with a valve seat of the large piston to 
constitute an opening valve. Further, in order to control or suppress too 
sensitive action of the small piston under low liquid pressure in the 
initial stage of stroke when actuating the opening valve with the liquid 
pressure exerted from the large piston to the small piston, the small 
piston is provided with an integral additional piston member of a still 
smaller diameter or is adapted to produce a frictional force in part of 
its portion coupled to the large piston. Still further, part of the 
cylinder wall is provided, at a position near the position of the end of 
downward stroke of either large or small piston, with an escapement hole 
related to either piston for releasing the residual liquid pressure so as 
to bring a sudden end to the spraying. 
Preferred embodiments of the invention will now be described with reference 
to the accompanying drawings. 
Designated at B is a bottle or other container accommodating a spray liquid 
such as cosmetic liquid, chemical, etc. It is formed on its portion 
adjacent to its open end with a male thread, on which a cap C is screwed 
such as to keep a pump cylinder A in a fixed position. The pump cylinder A 
has its flange 5 at its upper end fitted in the cap C and clamped between 
the inner wall of the top 6 of the cap and the end of the container B via 
a seal member 7 provided on the underside of the flange 5. 
The pump cylinder A includes an upper cylinder wall portion 1 of a large 
diameter and an integral lower cylinder wall portion 3 of a smaller 
diameter, and these large and small diameter cylinder wall portions 1 and 
3 accommodate respective large and small pistons a and b, which have such 
diameters that they are snugly fitted in the associated cylinder wall 
portions for reciprocal movement in the axial direction. In embodiments 
shown in FIGS. 6 and 7, pump cylinder A includes, in addition to upper 
large diameter cylinder wall portion 1 and lower small diameter cylinder 
wall portion 3 integral therewith via a shoulder 2, a further cylinder 
wall portion 3a integrally extending from the lower end of the small 
diameter cylinder wall portion 3 and having a smaller diameter than the 
diameter of the cylinder wall portion 3. In this case, small piston b is 
combined with an additional small piston b.sub.1. A spray liquid suck-up 
tube 8 has its upper end fitted in the lower end of the pump cylinder A, 
and its lower end (not shown) is usually located right above the bottom of 
the container B so that the liquid may be sucked up through it into a 
liquid chamber 9 in the cylinder by the action of the pump pistons. 
The large piston a, which occupies the interior of the large diameter 
cylinder wall portion 1 and serves to withdraw and compress the liquid, 
comprises a tubular member 10, an outer flange portion 10a integral with 
the lower end of the tubular member and a collar 11 integral with the 
outer periphery of the outer flange portion and in elastic contact with 
the cylinder inner wall so that it can be moved in the axial direction 
within the cylinder. 
The tubular member 10 is tightly fitted in the lower end portion of a valve 
tube 14, which penetrates a central opening 12 of the cap C to upwardly 
extend therefrom and carries a nozzle button 13 secured to its upper end, 
and it thus constitutes a plunger D together with the valve tube. Also, it 
has a central axial bore 16 communicating with the passage 15 in the valve 
tube 14 and is formed in an intermediate position of the bore with a valve 
seat 18 co-operating with a valve shoulder 17 of the small piston b to be 
described later. The portion of the bore 16 extending downwardly from the 
valve seat 18 has a comparatively large diameter and is a polygonal bore 
19 having a polygonal sectional shape, as most clearly shown in FIG. 4. 
In embodiments shown in FIGS. 6 to 9, the plunger does not have any tubular 
member, that is, valve tube 14 is integral with collar 11 constituting 
part of large piston a, with the valve seat formed at the lower open end 
or the intermediate position 18a of passage 15. 
Further, the central bore of the large piston a need not be a polygonal 
bore as will be made apparent hereinafter in relation to the small piston 
b. 
The small piston b, which occupies the interior of the small diameter 
cylinder wall portion 3, comprises a tubular member 20 integral with a 
lower end collar 21 in elastic contact with the cylinder inner wall so 
that it can be moved in the axial direction within the cylinder. More 
particularly, the small piston b, is an assembly comprising the tubular 
member 20, a cylinder 23 tightly fitted on the tubular member and a needle 
22 extending from the upper end of the cylinder. 
The liquid chamber is formed with the small piston b and the large diameter 
cylinder A. The pressure of liquid is on the increase, when the nozzle 
button 13 is downwardly pushed. The small piston b has an inner cavity 24, 
and the upper end of a bore 25 in the tubular member 20 open to the cavity 
24 is occupied by a check valve ball 26 which is adapted to be opened only 
when withdrawing liquid. Further, the wall of the cylinder 23 is formed 
with lateral holes 27 communicating the cavity 24 with the liquid chamber 
9 outside thereof so that liquid withdrawn by the action of the pump 
pistons may be led into the liquid chamber 9. 
The small piston b is always upwardly urged by the pressure provided by a 
bias spring 31 having a lower end thereof received in the bottom of the 
pump cylinder A, that is, the bias spring 31 serves to hold the small 
piston b in position at the upper end of the small diameter cylinder wall 
portion 3 and also hold a shoulder 29 of the cylinder 23 in engagement 
with the lower end of the large piston a. The needle 22 of the small 
piston b is loosely inserted in the central bore 16 of the tubular member 
10 such as to provide a liquid passage, and also it has a valve shoulder 
17 adapted to butt against the valve seat 18. 
The portion of the needle 22 occupying the interior of the polygonal bore 
19 has a diameter such that it is in contact with each side of the 
polygon, that is, its outer periphery is in partial contact with the inner 
wall of the bore, so that frictional force can be produced with the axial 
movement of the small piston b. This frictional force is provided in order 
to control or suppress sensitive downward action of the small piston b in 
response to liquid pressure exerted to it. In other words, it is desirable 
that the outer periphery of the needle is in partial contact with the wall 
of the bore while always providing a liquid passage. With such 
arrangement, there is no possibility of interferring with smooth pump 
operation. It is to be understood, although not illustrated, that 
regarding the frictional force produced between the needle 22 and 
polygonal bore 19 the same effects can be obtained by forming the needle 
22 as polygonal needle against the embodiment. 
In the embodiment of FIG. 6, the small piston b comprises a rod-like 
one-piece member 28 having an upper needle 22 and lower integral collars 
21 and 21a in elastic contact with the inner walls of the respective small 
cylinder wall portions 3 and 3a. The valve shoulder 17a of the small 
piston b is adapted to butt against the lower open end of the plunger D as 
the valve seat 18b, and a check valve ball 26 is provided at the bottom of 
the cylinder A. Further, the liquid chamber 9 is always communicated with 
the other chamber 9a by a lateral hole 27 formed in the small piston b. At 
the two points (21 and 21a), the small piston contacts with the cylinder 
inner wall, so it's frictional force against the inner wall is great. 
In the embodiments of FIGS. 7 and 8, the small piston b is an assembly 
consisting of a cylindrical member 23a having an upper needle portion 22 
and another tubular member 20a. The cylindrical member 23a having the 
needle 22 also has a lateral hole 27 and is tightly fitted on an upper end 
portion of the tubular member 20a, which has a collar 21b in elastic 
contact with the cylinder inner wall. The tubular member 20a has a central 
bore 25 in communication with the afore-mentioned lateral hole 27, and its 
lower end has an integral collar 21b in elastic contact with the inner 
wall of the cylinder wall portion 3a having a still smaller diameter. 
Check valve ball 26 is provided at the bottom of cylinder A, and the 
needle 22 of the small piston b has valve shoulder 17a adapted to butt 
against valve seat 18a formed within the plunger D. In FIG. 8, check valve 
ball 26 is provided to occupy the upper end of central bore 25 of the 
other tubular member 20a. Also in FIG. 8, in the small piston b collars 21 
and 21b constituting the piston have the same diameter and in frictional 
contact with the cylinder wall portion 3. This construction will provide a 
frictional force greater than that which can be expected from the other 
embodiments of the invention. 
In the embodiment of FIG. 9, the small piston b consists of a tubular 
member 23a having needle 22, lateral hole 27 and collar 21. Check valve 
ball 26 is provided at the bottom of cylinder A. The ball is surrounded by 
a lower end of a tubular member 30, which has its upper portion movably 
fitted in the tubular member 23a. The tubular member 30 has a collar 21c 
in elastic contact with the inner wall of the tubular member 23a. With 
this contact of the collar 21c frictional force similar to that mentioned 
hereinbefore is provided at the time of action of the small piston b. 
The upwardly urging force of a spring 31 is transmitted even to the plunger 
D. As shown in FIG. 2, a shoulder 14a of the valve tube 14 constituting 
the plunger D is urged against the lower open end of a tubular portion 32 
(cap C), and the plunger D is held in this state when the spray pump is 
out of use. In the FIGS. 6 to 9, the plunder D has the flange-like portion 
10a having the collar 11. The flange-like portion 10a is urged against the 
lower end of the tubular portion 32 of cap C. In the FIGS. 7 to 9, a 
packing 33 is interposed between the lower end of the tubular portion 32 
and the shoulder of the plunger D, in order to prevent leakage that might 
otherwise result from occasional turning-down of the container when the 
spray pump is out of use. 
In FIGS. 1 to 5, a cup-shaped packing 33 covers the tubular portion 32 of 
the cap C. It is fitted on the cap and secured thereto, with its edge of 
its button hole engaging the shoulder of the valve tube and with its 
bottom 34 having a small thickness to provide satisfactory flexibility. 
The packing 33 is in contact with the outer periphery of the plunger D 
during the plunger's downward moving. But, when the plunger upwardly 
moves, the packing's contacting part with the plunger's periphery is 
downwardly bent by the pressure difference between the inside and outside 
of the container B, thereby the space between the packing and the plunger 
arises. So, the pressure of the container's inside becomes equal to the 
that of the container's outside. Further, when residual liquid pressure 
within the cylinder is released in the structure of FIGS. 1 to 5, it 
serves to prevent leakage of liquid, which rushes upward along the outer 
periphery of the collar 11 and enters the opening 12 of the cap C. 
Designated at 35, as shown in FIGS. 2, 5, is an annular recess formed in 
the lower end of the inner wall of the large diameter cylinder wall 
portion 1 and having a diameter slightly greater than the inner wall 
diameter. 
It is adapted such that the lower end of the collar 11 of the large piston 
a is received in said recess in the last stage of the downward stroke of 
the large piston. 
At this stage, a gap or "escapement passage" is formed on the outer 
periphery of the collar 11 to provide communication between the liquid 
chamber 9 where the pressure is stored and the upper portion of the 
cylinder and also interior of the container, to thereby momentarily 
releasing reduced residual liquid pressure. 
While this "escapement passage" is provided in relation to the large piston 
a in the embodiment of FIGS. 1 to 5, in the embodiments of FIGS. 6 to 9 
this is replaced by a lateral hole 36, which is provided in the small 
diameter cylinder wall portion 3 such that it is possible for the collar 
21 of the small piston b to move downwardly over the lateral hole 26, 
thereby providing communication between the liquid chamber 9 and the 
interior of the container B for releasing the residual liquid pressure. 
Designated at 37 is a vent hole provided in an upper portion of the large 
diameter cylinder wall portion 1. 
In FIG. 5, a packing 38 is particularly provided between engaging faces of 
the large and small pistons a and b. It has an effect of assisting the 
valve action of the valve of the small piston b. 
With the spray pump according to the invention, by intermittently 
depressing the nozzle button with finger pressure the liquid pressure in 
the liquid chamber 9 is increased by the action of the large piston a. In 
the well-known construction of this type the valve of the small piston is 
immediately opened with a weak pressure that is developed in an initial 
stage of the downward stroke of the plunger. In contrast, with the 
embodiments mentioned above according to the invention, in which the small 
piston b is given an appropriate frictional force, against the small 
cylinder, the valve of the small piston is opened only with a high 
pressure, thus permitting a spray of atomized liquid to be suddenly 
produced from the nozzle button under a high pressure.