Automatic liquid soap dispenser

An automatic liquid soap dispenser includes a liquid soap container which receives liquid soap therein and which has a bottom wall that is formed with an outlet port. A tubular body is secured to a bottom surface of the bottom wall such that a through-hole at a closed rear portion of the tubular body is aligned with the outlet port. The closed rear portion of the tubular body is further formed with an upright soap outlet adjacent to the through-hole. A movable blocking member is provided adjacent to said closed rear portion and is movable to block and unblock the through-hole so as to control the flow of the liquid soap through the soap outlet. The plunger has a piston which extends fittingly and movably into the tubular body via an open front portion of the latter, and a flexible shaft portion connected to the piston. A driving unit is activated by a detecting unit upon detection of a target. The shaft portion of the plunger is coupled eccentrically to the driving unit so that activation of the driving unit results in reciprocal linear movement of the piston within the tubular body to dispense a predetermined amount of the liquid soap through the soap outlet. A switch unit is activated when the piston of the plunger completes one cycle of the reciprocal linear movement and deactivates the driving unit when activated.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a liquid soap dispenser, more particularly to an 
automatic liquid soap dispenser which is capable of supplying a 
predetermined amount of liquid soap when activated and which can prevent 
leakage of the liquid soap effectively. 
2. Description of the Related Art 
Liquid soap dispensers are installed in public toilets and deliver small 
amounts of liquid soap when operated. A first type of conventional liquid 
soap dispenser requires manual operation of the same before liquid soap 
can be delivered to the hands of a user. Liquid soap dispensers which 
belong to this type are inconvenient to use and are unsanitary since 
physical contact therewith may result in the contraction of germs. 
A second type of conventional liquid soap dispenser is capable of 
delivering automatically small amounts of liquid soap onto the hands of a 
user without manual operation thereof or physical contact therewith. 
Liquid soap dispensers which belong to this type usually employ an 
infrared unit to control the dispensing of liquid soap automatically. Upon 
detection of a target, such as the user's hands, the infrared unit 
activates a pump actuating unit to activate correspondingly a spring-type 
pump unit in order to dispense a predetermined amount of liquid soap from 
a soap container. This type of liquid soap dispenser is convenient to use 
and prevents the dispensing of excessive amounts of liquid soap. 
Prolonged use of liquid soap dispensers which belong to the second type, 
however, results in several drawbacks. For example, fatigue of the 
spring-type pump unit occurs, thereby affecting the ability of the pump 
unit to return to a fully-closed position and thereby diminishing the 
amount of liquid soap dispensed by the dispenser. Furthermore, leakage of 
the liquid soap can occur since the pump unit is unable to return to the 
fully-closed position. 
SUMMARY OF THE INVENTION 
The applicant of the present invention has a U.S. patent application, 
namely application Ser. No. 08/134,240 now U.S. Pat. No. 5,349,047, which 
discloses an automatic liquid soap dispenser that is constructed to solve 
the problems associated with the aforementioned conventional liquid soap 
dispenser. The object of the present invention is the same as that of the 
co-pending U.S. patent application, i.e. to provide an automatic liquid 
soap dispenser which is capable of supplying a predetermined amount of 
liquid soap when activated and which can prevent the leakage of liquid 
soap effectively. 
Accordingly, the automatic liquid soap dispenser of the present invention 
includes a liquid soap container, a flow control unit and an actuating 
unit. The liquid soap container confines a hollow space for receiving 
liquid soap therein and has a bottom wall which is formed with an outlet 
port and which has a bottom surface. The flow control unit includes a 
tubular body which has an open front portion and a closed rear portion 
that is formed with adjacent first and second annular outward projections 
which respectively confine a through-hole communicated with an interior of 
the tubular body. The tubular body is secured to the bottom surface of the 
bottom wall of the liquid soap container such that the through-hole of the 
first annular outward projection is aligned with the outlet port. The 
closed rear portion of the tubular body is further formed with an upright 
soap outlet which is disposed adjacent to and communicated with the 
through-hole of the second annular outward projection. The second annular 
outward projection has a lower end which is formed with a valve seat, and 
a movable blocking member which is disposed movably within the second 
annular outward projection and which is movable between a first position, 
wherein the blocking member rests on the valve seat so as to block the 
through-hole of the second annular outward projection, and a second 
position, wherein the blocking member moves away from the valve seat so as 
to unblock the through-hole of the second annular outward projection, 
thereby controlling flow of the liquid soap through the soap outlet. A 
plunger has a piston which extends fittingly and movably into the tubular 
body via the open front portion, and a flexible shaft portion which has a 
first end connected to the piston and a second end. The actuating unit is 
mounted on the liquid soap container and includes a detecting means which 
is used for detecting a target. A driving unit is connected to the 
detecting means and is activated by the detecting means upon detection of 
the target. The second end of the shaft portion of the plunger is coupled 
eccentrically to the driving unit so that activation of the driving unit 
results in reciprocal linear movement of the piston of the plunger within 
the tubular body, thereby moving the blocking member from the first 
position to the second position and dispensing a predetermined amount of 
the liquid soap through the soap outlet. A switch means is connected to 
the driving unit and is used for deactivating the driving unit when the 
piston of the plunger completes one cycle of reciprocal linear movement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 to 4, the preferred embodiment of an automatic liquid 
soap dispenser according to the present invention is shown to comprise a 
liquid soap container 10, an actuating unit 20, and a flow control unit 
30. 
Referring to FIGS. 1 and 2, the soap container 10 confines a hollow space 
11 for receiving liquid soap therein and has an open top via which the 
hollow space 11 is accessible. A cover plate 111 is mounted pivotally on 
the soap container 10 and normally closes the open top of the soap 
container 10. Liquid soap is poured into the hollow space 11 via the open 
top of the soap container 10 when the cover plate 111 is pivoted upward to 
open the open top. The soap container 10 has a bottom wall 113 which is 
formed with an outlet port 112 to permit the flow of liquid soap out of 
the hollow space 11. The bottom wall 113 has a bottom surface which is 
formed with a retaining groove 12, first and second gear axles 13, 14 
disposed adjacent to the retaining groove 12 on one side of the latter, a 
pair of opposed retaining hooks 15 on one side of the second gear axle 14, 
and adjacent first and second ring projections 16, 17. The first ring 
projection 16 is disposed around the outlet port 112. 
Referring to FIGS. 1 to 5 and FIG. 9, the actuating unit 20 includes a 
detecting means 24, a driving unit 23, and a switch means 22. The driving 
unit 23 includes a motor 231, a speed changing gear set and a driving gear 
2323. The switch means 22 is a contact switch which has a movable switch 
contact 221. The switch means 22 is used to control the operation of the 
motor 231. Operation of the motor 231 is initiated by the detecting means 
24 and is terminated by the switch means 22. In the present embodiment, 
the detecting means 24 is an infrared unit. The motor 231 has an output 
shaft 2310. The speed changing gear set includes a first small gear wheel 
2311 and a large gear wheel 2321. The first small gear wheel 2311 is 
mounted on the output shaft 2310 of the motor 231. The large gear wheel 
2321 is secured rotatably on the first gear axle 13 and meshes with the 
first small gear wheel 2311. A second small gear wheel 2322 is formed 
coaxially and integrally on one side of the large gear wheel 2321 so as to 
rotate with the large gear wheel 2321. The driving gear 2323 is secured 
rotatably on the second gear axle 14 and meshes with the second small gear 
wheel 2322. Therefore, rotation of the output shaft 2310 of the motor 231 
can result in corresponding rotation of the driving gear 2323. The driving 
gear 2323 has one side which is formed with an eccentric annular 
projection 2324. The switch means 22 is fixed to the bottom surface of the 
bottom wall 113 of the soap container 10 such that the movable switch 
contact 221 is disposed on one side of the second gear axle 14. 
Referring to FIGS. 1, 4 and 5, the flow control unit 30 includes a tubular 
body 31, a plunger 32, a movable first blocking member 35 and a second 
blocking member 34. The tubular body 31 has an open front portion 311 and 
a closed rear portion which is formed with a longitudinal cut-out, thereby 
forming an indented section 310 thereat. The indented section 310 is 
formed with adjacent first and second annular outward projections 36,33 
that respectively confine a through-hole 361,331 communicated with an 
interior of the tubular body 31. The first and second annular outward 
projections 36,33 extend fittingly into a respective one of the first and 
second ring projections 16,17 at the bottom wall 113 of the soap container 
10 when the tubular body 31 is secured onto the latter by means of a 
retaining member 21. The first annular outward projection 36 has a lower 
portion which is formed with four angularly spaced and inwardly projecting 
radial ribs 363 (only two are shown in FIG. 4). A passage 362 is defined 
between two adjacent radial ribs 363. The indented section 310 of the 
tubular body 31 is further formed with an upright soap outlet 332 which is 
disposed adjacent to the through-hole 331 of the second annular outward 
projection 33. The second annular outward projection 33 has a lower end 
which is formed with an inwardly projecting annular valve seat 333. An 
axially extending slit 334 is disposed above the valve seat 333 and 
communicates the through-hole 331 with the soap outlet 332. The second 
blocking member 34 is disposed movably within the first annular outward 
projection 36 and has a plug surface 341. The plug surface 341 of the 
second blocking member 34 has a diameter greater than that of the outlet 
port 112 of the soap container 10. It should be noted that the second 
blocking member 34 normally rests on the ribs 363. At this stage, liquid 
soap in the hollow space 11 of the soap container 10 will flow into the 
tubular body 31 via the passages 362 in the through-hole 361 confined by 
the first annular outward projection 36. The movable blocking member 35 is 
disposed movably within the second annular outward projection 33 and 
includes a sealing block 352 which is movable between a first position, 
wherein the sealing block 352 rests on the valve seat 333 so as to block 
the through-hole 331 of the second annular outward projection 33, and a 
second position, wherein said sealing block 352 moves away from the valve 
seat 333 so as to unblock the through-hole 331 of the second annular 
outward projection 33, thereby controlling flow of the liquid soap through 
the soap outlet 332. The movable blocking member 35 further includes a 
resilient element 351 which is interposed between the sealing block 352 
and the bottom wall 113 of the soap container 10 and which normally biases 
the sealing block 352 so as to retain the latter in the first position. In 
the present embodiment, the resilient element 351 is a compression spring, 
while the sealing block 352 is a cylindrical pin. 
The plunger 32 is made of a flexible plastic material and has a piston 323 
which extends fittingly and movably into the tubular body 31 via the open 
front portion 311 of the latter. The plunger 32 further has a flexible 
shaft portion 324 which interconnects the piston 323 and a retaining ring 
321. The retaining ring 321 is sleeved around the eccentric annular 
projection 2324 of the driving gear 2323 and is formed with a switch 
actuator 322 which projects radially outward therefrom. Whenever the 
driving gear 2323 completes one revolution, the switch actuator 322 
presses against the movable switch contact 221 of the switch means 22 so 
as to activate the latter. 
Referring to FIG. 3 and FIGS. 5 to 10, upon detection of a target, such as 
the hands of a user, the detecting means 24 activates the motor 231, 
thereby causing the driving gear 2323 to rotate. Clockwise rotation of the 
driving gear 2323 causes the piston 323 of the plunger 32 to move linearly 
within the tubular body 31 from the position shown in FIG. 5 to the 
position shown in FIG. 10. Under this condition, the piston 323 forces the 
liquid soap inside the tubular body 31 to move the sealing block 352 from 
the first position to the second position, thereby permitting the flow of 
liquid soap in the tubular body 31 through the soap outlet 332 via the 
slit 334, as shown in FIG. 7. As the piston 323 of the plunger 32 moves 
from the position shown in FIG. 5 to the position shown in FIG. 10, the 
second blocking member 34 is also forced to move upwardly such that the 
plug surface 341 abuts against the bottom wall surface of the bottom wall 
113 of the soap container 10, thereby blocking the outlet port 112 of the 
soap container 10, as shown in FIG. 7. 
When the piston 323 reaches the position shown in FIGS. 8 and 10, further 
clockwise rotation of the driving gear 2323 causes the piston 323 of the 
plunger 32 to move within the tubular body 31 from the position shown in 
FIG. 10 back to the position shown in FIG. 5. Under this condition, the 
piston 323 moves away from the closed rear portion of the tubular body 31. 
The sealing block 352 within the second annular outward projection 33 
blocks the valve seat 333 to prevent the flow of liquid soap through the 
slit 334, as shown in FIG. 10. At the same time, the second blocking 
member 34 rests on the ribs 363 and liquid soap flows from the soap 
container 10 and into the tubular body 31 via the passages 362 in the 
through-hole 361 of the first annular outward projection 36. Eventually, 
the switch actuator 322 on the retaining ring 321 of the plunger 32 
presses against the movable switch contact 221 of the switch means 22 so 
as to activate the latter. At this instant, the switch means 22 disrupts 
the flow of current from a power source (P) to the motor 231, thereby 
deactivating the motor 231. It should be noted that as the driving gear 
2323 completes one revolution, the piston 323 of the plunger 32 completes 
one cycle of reciprocal linear movement within the tubular body 31. 
It has thus been shown that the present invention is capable of supplying a 
predetermined amount of liquid soap when activated. Furthermore, the 
provision of the ball valve unit can prevent the leakage of liquid soap 
effectively. 
While the present invention has been described in connection with what is 
considered the most practical and preferred embodiment, it is understood 
that this invention is not limited to the disclosed embodiment but is 
intended to cover various arrangements included within the spirit and 
scope of the broadest interpretation so as to encompass all such 
modifications and equivalent arrangements.