Liquid-operated actuator assembly, particularly for a flush toilet, and flush toilet incorporating the assembly

A fluid-operated actuator assembly has a valve with an inlet for connection to a pressurized fluid source, a bi-stable electromagnetic device for operating the valve, which has a first state closing the valve and a second state opening the valve, a hydraulic actuator, and an electronic control circuit. The hydraulic actuator has an actuating member in a housing, the housing having a chamber on one side of the actuating member to which an outlet of the valve is connected for receiving fluid from the fluid source when the valve is opened, the actuating member for operation of the hydraulic actuator. The control circuit momentarily energizes the bi-stable electromagnetic device to the hydraulic actuator from the second state, back to the first state, to terminate operation of the hydraulic actuator.

The present invention relates to a fluid-operated actuator assembly which is particularly, but not exclusively, suitable for use in connection with sanitary wares such as a toilet.

BACKGROUND OF THE INVENTION

Battery-operated actuator assembly is known for use in controlling the flow of water in the toilet. Taking as an example, automatic facets will, upon detection of the hands of a user, open and supply water for a certain period of time. These faucets are operated by battery cells. As the power consumption is generally not low, the battery life is usually short and hence replacement of battery cells can be frequent.

The invention seeks to mitigate or to at least alleviate such a problem or shortcoming by providing a fluid-operated actuator assembly.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a fluid-operated actuator assembly comprising a valve having an inlet and an outlet, the inlet being for connection to a pressurized fluid source, a bi-stable electromagnetic device for operating the valve, the bi-stable electromagnetic device having a first state closing the valve and a second state opening the valve, a hydraulic actuator, and an electronic control circuit. The hydraulic actuator comprises an actuating member in a housing, the housing having a chamber on one side of the actuating member to which the outlet of the valve is connected for receiving fluid from a said fluid source when the valve is opened by the bi-stable electromagnetic device in order to act upon and move the actuating member for operation of the hydraulic actuator. The electronic control circuit is for momentarily energizing the bi-stable electromagnetic device to change it from the first state to the second state to enable operation of the hydraulic actuator and subsequently from the second state back to the first state to terminate operation of the hydraulic actuator.

Preferably, the bi-stable electromagnetic device comprises a latching solenoid.

Preferably, the actuating member comprises a piston which is movable within the housing.

In a preferred embodiment, the housing has a cylindrical interior with a central axis, and the piston is angularly movable about the central axis.

It is preferred that the hydraulic actuator comprises a hydraulic motor.

In a preferred embodiment, the housing has a cylindrical interior with a central axis, and the piston is movable linearly along the central axis.

More preferably, the piston is freely slidable, with or without bias, in opposite directions along the housing.

It is preferred that the hydraulic actuator comprises a hydraulic cylinder.

In a preferred embodiment, the actuating member is arranged to be acted upon and moved by said fluid from an inoperative position to an operative position member for operation of the hydraulic actuator and to be held in the operative position.

More preferably, the chamber includes a pressure limiter for limiting pressure of fluid received in the chamber acting upon the actuating member.

Further more preferably, the pressure limiter comprises a leak in the housing positioned for exposure to the chamber when the actuating member reaches the operative position.

Yet further more preferably, the leak is provided by a hole through a wall of the housing.

Yet further more preferably, the fluid-operated actuator assembly includes a reservoir for collecting said fluid leaking out through the leak.

It is preferred that said fluid received in the chamber is arranged to be flowing through the chamber while exerting a non-static pressure upon the actuating member when the actuating member reaches the operative position.

It is preferred that the fluid-operated actuator assembly includes a draining device for draining said fluid from the chamber upon termination of operation of the actuating member, as the actuating member returns to the inoperative position.

It is further preferred that the draining device comprises a spring-loaded valve.

It is yet further preferred that the spring-loaded valve is connected to permit flow of fluid along one of two paths and is arranged to be opened for a first path and closed for a second other path or closed for the first path and opened for the second other path

It is preferred that the draining device is provided in a path running between the valve and the housing.

It is preferred that the valve includes a pilot valve.

Advantageously, the electronic control circuit includes a switching component for operating the bi-stable electromagnetic device.

In a preferred embodiment, the electronic control circuit is battery-operated.

According to a second aspect of the invention, there is provided a toilet cistern incorporating the aforesaid fluid-operated actuator assembly, including a body acting as a reservoir for holding water for flushing, and a flushing mechanism comprising a flushing valve located at a bottom of the body for flushing water held in the body. The flushing valve is operable upon being lifted by a driving force from the actuating member as the actuating member is moved by said fluid.

Preferably, the flushing valve is coupled to the actuating member by means of a motion converter which converts the motion of the actuating member into an upward motion for lifting the flushing valve.

Preferably, the actuating member is arranged to support partially the weight of the flushing valve when the actuating member is moving from the inoperative position to the operative position while lifting the flushing valve, and later to return to the inoperative position under the action of the weight of the flushing valve.

According to a third aspect of the invention, there is provided a toilet incorporating the aforesaid toilet cistern, including a toilet bowl to which the toilet cistern is close coupled.

According to a fourth aspect of the invention, there is provided a toilet incorporating the aforesaid fluid-operated actuator assembly, including a toilet bowl, a lid for the toilet bowl, and a connecting member connecting the lid on the toilet for movement between a closed position and an open position. The lid is arranged to be opened or closed by a driving force from the actuating member as the actuating member is moved by said fluid.

Preferably, the toilet includes a gear system provided between the actuating member and the lid for transmitting the driving force from the actuating member to the lid.

More preferably, the gear system is adapted to transmit the driving force to move the lid between the closed and open positions and to flip the lid to have its underside facing to the back in the open position.

More preferably, the gear system is physically associated with the connecting member.

Further more preferably, the connecting member is elongate having two opposite ends, with one end connected relative to the toilet bowl and the opposite end connected to the lid.

Yet further more preferably, the gear system is provided inside the connecting member.

It is preferred that the gear system comprises a plurality of gears and a belt disposed on a plurality of axles.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIGS. 1 to 15Aof the drawings, there is shown a fluid-operated actuator assembly10which is installed in a cistern20of a flush toilet, both employing the invention. The actuator assembly10comprises a valve100having an inlet110and an outlet120, a bi-stable electromagnetic device200for operating the valve100, a hydraulic actuator300, and an electronic control circuit400for energizing the electromagnetic device200. The valve inlet110is for (direct or indirect) connection to a pressurized water source e.g. domestic tap or flush water source1by means of a pipe2for supply of water to operate the hydraulic actuator300.

The electromagnetic device200is preferably implemented by a bi-stable or latching solenoid200having a first state closing the valve100and a second state opening the valve100. The latching solenoid200has a cylindrical iron casing210, a solenoid coil220co-axially within the casing210and, along a central axis of the casing210, a pole piece240, a permanent magnet230located between the casing210and an inner end of the pole piece240, and a spring-loaded plunger250adjacent an outer end of the pole piece240. The plunger250is resiliently biased by a coil spring260compressed between the plunger250and the pole piece240, at a small distance off the pole piece240in an unlatched position. The permanent magnet230has a magnetic field which is in line with that of the solenoid coil220in one polarity but counteracted by the coil's magnetic field in the reversed polarity.

In operation, when the solenoid coil220is triggered or energized (e.g. by a positive electrical pulse) in the same polarity as the permanent magnet230, the plunger250will be attracted to slide towards and to bear against the pole piece240, counteracting the spring260, through a very short stroke and stay in such a latched position, i.e. the second state holding the valve100open, even if the energizing voltage is switched off. At a later time, after say 6 to 9 seconds, when the solenoid coil220is energized in the reversed polarity (e.g. by a negative electrical pulse), its magnetic field will counteract and neutralize the magnetic field of the permanent magnet230, thereby releasing the plunger250, which will then return to its original unlatched position, i.e. the first state holding the valve100closed, under the action of the spring260.

The latching solenoid200normally stays in the first state, without consuming any electrical power, to hold the valve100normally closed. The latching solenoid200will upon a brief electrical trigger change to the second state to open the valve100and hold it open without power consumption, until the next trigger in the opposite polarity is applied.

The valve100is hereinafter referred to as the main valve100, which is operated by the latching solenoid200via a considerably smaller and less powerful pilot valve90which is installed immediately in front of the plunger250.

The pilot valve90is formed by a valve member91embedded in the plunger250and a valve seat92with which the valve member91normally seals. Externally, the pilot valve90has an inlet93and an outlet94which are in communication with each other via a passage93-94through the valve seat92such that the passage93-94is controlled by the pilot valve90and in turn by the latching solenoid200. The pilot valve90normally shuts the passage93-94to in turn close and keep the main valve100normally closed.

As to construction, the main valve100is formed by a valve member101with which a valve seat102normally seals, and includes a cylindrical core130whose one end131acts as the valve seat102and opposite end132leads to the main valve outlet120. The valve member101is a flat rubber disc which, while normally bearing flat against and hence sealing with the valve seat102, has a flexible periphery101A of a reduced thickness and bent cross-section such that the valve member101is retractable to disengage from the valve seat102.

The valve member101extends across the interior of the main valve100and divides the same into a front interior or chamber100A and a rear interior which is further divided by the cylindrical core130into an outer chamber100B surrounding the core130and an inner chamber100C within the core130. The front chamber100A is in communication with the inlet93of the pilot valve90, and the outer and inner chambers100B and100C in communication with the main valve inlet110and outlet120respectively. The outlet94of the pilot valve90is connected to the main valve outlet120.

A small hole101B through the valve member101equalizes the pressure between the front and outer chambers100A and100B when the pilot valve90is closed holding water in the front chamber100A. In this condition, water fed from the water source1into the outer chamber100B (and also into the front chamber100A through the hole101B) is blocked against flowing into the inner chamber100C by the valve member101in sealing engagement with the valve seat102, i.e. when the main valve100is closed (FIG. 5).

Upon energization, the latching solenoid200opens the pilot valve90, and this results in loss of water from the front chamber100A via the pilot valve90and hence pressure drop in the front chamber100A (FIG. 6). The lost water flows from the outlet94of the pilot valve90to the main valve outlet120for downstream operation.

With water being fed into the outer chamber100B via the inlet110of the main valve100, the pressure in the outer chamber100B substantially maintains and hence becomes relatively higher than that in the front chamber100A. The valve member101consequently retracts and disengages from the valve seat102, thereby giving way to let water from the outer chamber100A flow into the inner chamber100C and then out of the main valve100via its outlet120(FIG. 7). The main valve100is thus opened.

The main valve100controls the main flow of water from the water source1to operate the hydraulic actuator300, at a relatively high pressure or high flow feed. The pilot valve90is a smaller valve that controls a limited-flow control feed to the main valve100, thereby allowing a small and easily operated feed to control a much higher pressure or higher flow feed, which would otherwise require a much larger force to operate. The pilot valve90is used to enable the use of a relatively less powerful latching solenoid200.

Alternatively, in a slightly different embodiment of the subject fluid-operated actuator assembly of a simpler construction, a relatively more or sufficiently powerful latching solenoid (200) may be employed to directly operate the main valve (100) for controlling the main flow of water, thereby eliminating use of the pilot valve (90).

As to the hydraulic actuator300, it may be implemented by a hydraulic cylinder as in this embodiment, which is also designated by reference numeral300, or alternatively a hydraulic motor in a latter embodiment. A hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke, also known as a linear hydraulic motor. A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement i.e. rotation, and is the rotary counterpart of a hydraulic cylinder.

In passing, it is noteworthy that any other suitable forms of hydraulic actuator may be employed, dependent upon the required type of actuating motion, input/output power and physical size, etc.

The hydraulic cylinder300has an actuating member, which is typically a piston310, movably mounted in a barrel or housing320having a cylindrical interior with a central axis. The piston310is in sealed but sliding engagement within the housing320. The housing320is oriented with its central axis extending horizontally (see e.g.FIG. 14). The piston310is freely slidable, under no specific biasing force (for simplicity and as is unnecessary in this embodiment), in opposite directions, co-axially and linearly along the central axis of the housing320.

It is intended that a certain degree of bias may be included for the piston310, e.g. by using an extension or torsion spring, when the operation warrants it e.g. to provide an adequate force for return of the piston310.

The piston310includes a rod330as the point of actuation, which projects forward from the piston310along its central axis and out through a front end of the housing320. The housing320has a front chamber322on one or the front side of the piston310as the rod330and a rear chamber321on the rear side of the piston310opposite the rod330. The outlet120of the main valve100is connected indirectly by means of a pipeline P (or directly) to, or generally stated in communication with, the chamber321for receiving water flowing from the water source1via the main valve100when the main valve100is opened by the latching solenoid200, such that the water acts upon and moves the piston310for operation of the hydraulic cylinder300.

Water entering the rear chamber321acts upon the piston310for moving the piston310and in turn extending the rod330forward from an inner inoperative position to an outer operative position, thereby performing a push action, and for subsequently holding the rod330in the operative position i.e. extended.

The housing320has a linear slot323generally in the front chamber322, which extends axially at the lowest position of the housing's horizontally-lying cylindrical wall. The slot323extends from its one end situated at the front end of the housing320for a certain length greater than the (effective) thickness of the piston310such that its other end323X will be exposed to the rear chamber321right behind the piston310when the piston310is pushed by water in the rear chamber321sufficiently forward along the housing320, where it locates the rod330in the latter's operative position. The slot's exposed end323X is a hole that represents a leak through the housing's wall for the rear chamber321, when the rod330reaches its operative position.

Upon exposure of such a leak to the rear chamber321, the water in the chamber321finds its way out of the housing320. The leak is of an optimum size, i.e. not too large and not too small, just sufficient to limit the pressure of the water in the rear chamber321acting upon the piston310at a certain level while water is being continuously replenished from the water source1via the main valve100and flowing through the rear chamber321. While flowing in the rear chamber321, the water exerts a non-static pressure upon the piston310when the rod330reaches its operative position, which is sufficient to keep the rod330in the operative position.

The leak acts as a pressure limiter for water in the rear chamber321of the housing320. It avoids over-pressure in the rear chamber321, which otherwise may thrust the piston310too hard against the front end of the housing320or shatter the housing320. Apart from protecting the hydraulic cylinder300, the pressure limiter also improves the response time during return of the piston310. The pressure limiter is an enhancement feature.

The control circuit400is implemented by an MCU410and may include an electrical triggering device which may be provided by, for example, a pushbutton switch or a remote sensor420for triggering the control circuit400to operate, and is battery-operated by one or more battery cells430. The MCU410has an output pin connected to an electronic or solid-state switching component, such as a BJT transistor or MOSFET, for controlling the latching solenoid200by momentarily applying an electrical signal via the switching component to the latching solenoid200in order to change it from the first state (closing the main valve100) to the second state (opening the main valve100) thereby triggering the operation of the rod330and, subsequently after a predetermined period of time of operation has elapsed (e.g. 10 seconds) with a second electrical signal to change the latching solenoid200from the second state back to the first state for terminating the operation of the rod330.

The first electrical signal may be a positive electrical pulse, and the second electrical signal a negative electrical pulse, both having a pulse width of about 20 ms (millisecond). The duration of the electrical pulses is sufficiently long (say at least 5 ms) for the valve member101of the main valve100to respond (i.e. changing position relative to the valve seat102) to the opening/closing of the pilot valve90.

The rod330is arranged to return to its original inoperative position, i.e. to recede, upon expiration of the aforesaid predetermined period of time of operation. The rod330is only able to recede when the water behind the piston310gives way or, for example, is drained as in the case of the described embodiment. A draining device500is employed for this purpose, which kicks in upon termination of operation of the rod330, as the rod330returns or is returning to the inoperative position.

The draining device500is a spring-loaded valve as provided by a shuttle valve500provided in a path running between the main valve100and the housing320of the hydraulic cylinder300. The shuttle valve500is formed by a valve member510reciprocating between a first valve seat520in communication with the main valve outlet120and a second valve seat521in communication with a drain hole530, with the valve member510being biased by a coil spring540to normally seal with the first valve seat520, off the second valve seat.

Hence the shuttle valve500is normally closed for the main valve outlet120and normally open for the drain hole530. Upon opening for the main valve outlet120, the shuttle valve500closes for the drain hole530, and vice versa. In general, the shuttle valve500is connected to permit flow of fluid along one of two paths and is arranged to be opened for a first path and closed for a second other path or conversely closed for the first path and opened for the second other path. Specifically, the shuttle valve500allows fluid to flow past it along one of two paths associated with the main valve outlet120and the drain hole530respectively.

On its way from the outlet120of the main valve100to the housing320of the hydraulic cylinder300, water running from the main valve's core130presses upon the valve member510head-on and thus opens the shuttle valve500(counteracting the spring540) for flowing into the housing320, thereby advancing the piston310and extending the rod330(FIGS. 8 to 9). The shuttle valve500will remain open to permit this flow for as long as water is running past it in this direction into the hydraulic cylinder300.

At the end of the aforesaid predetermined period of time of operation, the latching solenoid200is energized to close the pilot valve90(FIG. 10) and in turn also the main valve100(FIG. 11), thereby stopping the flow of water from the water source1into the subject actuator assembly10. Water pressure drops instantly, and this at once leads to two consequences: cessation of the pushing action of the rod330and self re-opening of the shuttle valve500(by its own spring540) for the drain hole530(FIGS. 11 and 12).

The rod330immediately returns to its inoperative position under the action of a force (e.g. an external force as hereinafter described), causing the piston310to press the water in the rear chamber321of the actuator's housing320out and back to the shuttle valve500(FIGS. 11 to 12). With the shuttle valve500now opens for the drain hole530, the water escapes and drains out of the fluid-operated actuator assembly10. The actuator assembly10then will return or is reset to its original condition (FIG. 13) ready for the next operation.

In this particular embodiment, the actuator assembly10further includes a motion converter in the form of a hinge mechanism600for changing the direction of action of the actuating member i.e. the piston310or rod330. The hinge mechanism600is formed by a C-shaped bracket610connected to a base620by means of a hinge630for pivotal movement relative thereto. The base620is mounted on the aforesaid one-piece housing immediately in front of and about the rod330, such that the rod330is aligned to engage, and push, the bracket610by a small pedal611of the bracket610.

As the rod330is extended from the inoperative position to the operative position, it pivots the hinged bracket610upwardly anti-clockwise to an upper operative position (FIG. 15). Later, the bracket610may pivot or be pivoted downwardly clockwise back to a lower inoperative position, thereby pushing and returning the rod330back to the inoperative position. The hinged bracket610acts as a modified actuating member of the hydraulic cylinder300, which operates in a different manner and/or direction compared to the rod330.

The fluid-operated actuator assembly10is designed for installation and use, among its intended applications, with a flush toilet that has a toilet bowl30, to which a toilet cistern20is close coupled and on which a two-piece hinged seat40and toilet bowl lid50is typically mounted on the back of the toilet bowl30to allow covering the toilet or sitting (or not) while using the toilet. The toilet cistern20has a body or tank21acting as a reservoir to hold water for toilet flushing, and includes a flushing mechanism700which includes a flushing valve710located at the bottom of the tank21for flushing water out of the tank21.

The fluid-operated actuator assembly10may be employed to trigger flushing of the toilet in a first embodiment, or to open and close the lid50in a second embodiment.

In the first embodiment, the fluid-operated actuator assembly10is mounted within the top of the tank21, with the hydraulic cylinder300and the shuttle valve500inside the tank21and the main valve100and in particular the latching solenoid200outside the tank21for waterproof or at least to avoid excessive exposure to moisture. A string or chain720connects or couples an uppermost end of the flushing valve710to a tip of the hinged bracket610of the hinge mechanism600of the actuator assembly10.

The flushing valve710is operable upon being lifted by a driving force from the hinged bracket610(acting as a modified actuating member) as the bracket610is pivoted from the lower to the upper position corresponding to the inoperative and operative positions of the rod330. The valve710operates by being opened wide to let water to rush down from the tank21into the toilet bowl30, thereby performing a flushing cycle which should take about 6 to 9 seconds to complete.

The hinge mechanism600includes a hinge for converting the horizontal motion of the rod330into vertical or upward motion for lifting the flushing valve710. The hinged bracket610is arranged to support the weight of the flushing valve710(in the water) when it is being pivoted from the lower inoperative position to the upper operative position, while lifting and hence opening the flushing valve710.

Upon completion of the flushing cycle, by virtue of gravitational force, the bracket610is later returned to the lower position under the action of the weight of the flushing valve710. This returns or resets the actuator assembly10to its original condition ready for the next flushing operation.

To cater for an insufficient weight of the flushing valve710to reset the actuator assembly10to its original condition (i.e. pushing the actuating rod330back) or to avoid excessive hindering upon descend of the flushing valve710, a spring may be installed inside the hydraulic cylinder300to bias the piston310rearward.

During operation of the actuator assembly10, water that leaks out through the exposed hole323X of the hydraulic cylinder300and water that drains out from the shuttle valve500is collected in the same reservoir below provided by the tank21of the toilet cistern20.

Optionally, an extra set100X of the main valve100, latching solenoid200and control circuit400(FIGS. 2 and 2A) may be used for controlling refill of the toilet cistern20with water after each flushing operation.

Reference is now also made toFIGS. 16 to 24of the drawings. In the second embodiment, the fluid-operated actuator assembly10is installed to drive a mechanism which includes a gear system in the form of a gear train70, which in turn opens and closes the lid50.

The toilet bowl30has on its back a bidet module31, to which the seat40is hinged and the lid50is pivotably connected by means of one or more connecting members in the form of a pair of pivotal arms32on opposite left and right sides of the toilet, its lid50and the bidet module31. The seat40and lid50are independently pivotable up and down, freely for the seat40which thus requires manual operation but automatically for the lid50as driven by the actuator assembly10.

Each pivotal arm32is an elongate hollow member, having a rear end32A connected by means of a rear hinge axle61to the relevant side of the bidet module31and including a front end32B connected by means of a front hinge axle to the same side of the lid50at about its mid-length. Internally of or inside the right arm32, unlike the left arm32, there is installed a gear train70for drive transmission.

The gear train70is built by 1stto 8thgears71to78and a belt in the form of a timing belt79, all of which are mounted about the two hinge axles61and63and two extra axles62and64positioned on opposite sides of the hinge axle61. The axles61to64are also referred to as the 1stto 4thaxles, with the axle64for rotational drive input and the axles61and63for rotational drive outputs.

The gears71and77are a compound gear mounted fast on the axle64for rotation by or with the axle64, with either one of the axle64and the gear77arranged to receive rotational drive for turning of the axle64. The gears73and78are another compound gear which is mounted fast on the axle61for simultaneous turning to transmit rotational drive from the latter to the former, with the gear72supported between them on the axle61for free rotation thereabout.

The gear72is attached, secured or otherwise fixed to the right arm32for pivoting the same as it is being turned by the gear71in mesh with it. The gear71receives rotational drive from the gear77or the axle64or via the latter, and in turn rotates the gear72to pivot the right arm32and hence the lid50in opposite directions. In particular, upon anti-clockwise rotation the gear77and hence the gear71turns the gear72clockwise to pivot the right arm32up to open the lid50(FIGS.16/16A to18/18A). Upon subsequent clockwise rotation the gear77and hence the gear71turns the gear72anti-clockwise to pivot the right arm32down to close the lid50(FIGS.18/18A to16/16A).

With the gear72being freely rotatable about the axle61, the gear78receives rotational drive from the gear77and then passes on the rotational drive through to the gear73past the gear72while the gear72, upon being turned by the gear71, is opening or closing the lid50.

The gears74and75are yet another compound gear which is disposed about the axle62for simultaneous free rotation, with the gear74in mesh with the gear73for turning thereby such that the rotational drive reaches the gear75. The last gear76is mounted fast on the axle63for rotation thereby. The timing belt79is stretched across the gears75and76for transmitting rotational drive from the gear75at the rear end32A of the right arm32along the length of the arm32to the gear76at the front end32B. The gear76, while being driven by the axle63, is coupled with the lid50for outputting the rotational drive to flip the lid50as the lid50is being opened or closed.

Here comes a rundown on the operation. Being applied to the axle64optionally via the gear77, the rotational drive is split and transmitted along two paths. The first path extends from the gear77, via the axle64and gear71, to reach the gear72, which then pivots the right arm32up to open the lid50(FIGS.16/16A to18/18A) or down to close the lid50(FIGS.18/18A to16/16A). The second path extends from the gear77and then the gear78through to the gear73, then past the gear gears74to75and via the timing belt79to reach the gear76, which then flips the lid50back up as the lid50is being opened (FIGS.16/16A to18/18A) or flips the lid50back down as the lid50is being closed (FIGS.18/18A to16/16A).

The lid50is pivoted and flipped simultaneously between a normal closed position and a full open position in which the lid's underside (considered unhygienic) faces to the back off a user.

The fluid-operated actuator assembly10is installed inside the bidet module31, externally of the cistern20, with appropriate pipelines connected to the water source1for supply of water and to the cistern20for discharging water thereto.

To drive the gear train70, the actuator assembly10may incorporate either a hydraulic cylinder300C or a hydraulic motor300M, which is located adjacent the right arm32.

The majority of the other components of the actuator assembly10as described above remain usable, but two sets of such components are installed, the first set for opening the lid50and the second set for closing (FIGS. 23 and 24). The two sets of components are denoted by the same reference numerals as used above but with a suffix “A” for the first set and suffix “B” for the second set, e.g. main valve100A, latching solenoid200A and shuttle valve500A for opening the lid50, and main valve100B, latching solenoid200B and shuttle valve500B for closing the lid50.

The hydraulic actuator300C/300M may have to be detached from such other components, or its orientation changed, to allow for the nature and/or direction of its drive output vis-à-vis the gear train70.

In the case of a hydraulic cylinder300C being used, it has generally the same structure as the earlier hydraulic cylinder300with equivalent parts designated by the same reference numerals suffixed by a letter “C”. The front chamber322C does not have an equivalent of the aforesaid slot323, as it is utilized in the same manner as the rear chamber321C but in conjunction with the extra second set of components including the main valve100B, latching solenoid200B and shuttle valve500B (FIG. 23) for closing the lid50.

Thus, pressurized water in the rear chamber321C pushes the piston310C forward to open the lid50and, in the subsequent operation, water in the front chamber322C pushes the piston310C backward to close the lid50. The hydraulic cylinder300C is reversible in operation to accomplish the opening and closing actions upon the lid50in opposite directions.

To apply the linear driving force from the hydraulic cylinder300C to turn the gear train70, a crank-and-slider mechanism65(FIG. 21) is connected between the rod330C of the cylinder300C and the drive input axle64of the gear train70, with a crank part66coupled with the axle64and a slider part67connected to the rod3300. The cylinder300C is hinged at the rear/bottom end of its housing320C such that the cylinder3000is pivotable back and forth to permit the operation of the crank-and-slider mechanism65.

In the case of a hydraulic motor300M being used, it has a housing320M with a cylindrical interior, a piston310M supported co-axially in the housing320M for angular movement i.e. rotation about a central axis (hence also known as rotor), and a central shaft330M extending from the piston or rotor310M out of the front end of the housing320M. The rotor310M has a number of corner parts known as vanes which divide the interior of the housing320M into a number of (moving) chambers or compartments which, depending on the relative angular position of the rotor310M, are in communication with the exterior via a first input/output port321M and a second input/output port322M. A pinion331M fitted on the shaft330M, which is in mesh with the gear77, outputs rotational drive to the gear train70.

The first set of components, including the main valve100A, latching solenoid200A and shuttle valve500A, are associated with the first input/output port321M for delivering pressurized water into and out of the housing320M via separate chambers thereof. In operation, force differential created by unbalanced force of the pressurized water on the vanes turns the rotor310M in one direction, e.g. clockwise, for the shaft330M to drive the gear train70to open the lid50.

The second set of components, including the main valve100B, latching solenoid200B and shuttle valve500B, are associated with the second input/output port322M for delivering pressurized water into and out of the housing320M via separate chambers thereof. In subsequent operation, reversed force differential created by unbalanced force of the pressurized water on the vanes turns the rotor310M in the opposite anti-clockwise direction for the shaft330M to drive the gear train70to close the lid50.

The shaft330M or the rotor310M driving the shaft330M is another example of the actuating member of the subject fluid-operated actuator assembly.

Overall, depending on which one of the input/output ports321M and322M is used for feeding pressurized water, the hydraulic motor300M may be driven to rotate in opposite directions to accomplish both opening and closing actions upon the lid50.

To apply the rotary driving force from the hydraulic motor300M to turn the gear train70, a speed-reduction gearbox (not shown) may be installed between the shaft330M of the motor300M and the axle64of the gear train70.

In general, either one or both of the arms32may be equipped with a gear train70(i.e. gears71to78and axles61to64) for drive transmission to open and close the lid50depending on the weight of the lid50or the torque required to support it. In future embodiments, a single central arm may be employed to operate the lid for a neat and balanced design. In addition, a similar pivoting mechanism may also be installed for lifting and lowering the seat40for a fully automated operation.

The fluid-operated actuator assembly, or the actuator in short, of the subject invention is powered by the pressurized water from a tap or flush water source. A bi-stable electromagnetic device, e.g. an electrical latching solenoid valve, is used to control the water flow from the water source. While the solenoid valve is opened, it lets in water which then triggers the actuator to operate the flushing valve, thereby letting water in the cistern to discharge immediately into the toilet bowl and flush away waste in the bowl. This arrangement utilizes the supply water pressure as the major power source to complete the toilet flushing operation.

The bi-stable electromagnetic device only requires an electrical signal of a limited duration to change state. Once latched, the latching solenoid will stay in the latched position without the need of electrical power, and hence no or very little electrical power is consumed or the power source may be turned off. Power consumption is therefore low and this enables use of battery power to control the actuator itself driven by pressurized water or fluid in general available in situ. Since the flushing mechanism is driven by the supply water pressure, the power consumption of the control electronics and latching solenoid is extremely low.

The invention makes it possible for a battery-operated toilet flushing system to function with a reasonable operating time before battery runs flat. By calculation, a battery cell can trigger over 30,000 times flushing cycles in 3.5 years of normal use.

In general, the fluid-operated actuator assembly of the subject invention could be powered by other forms of energy means instead of batteries, such as AC, hydro or solar power.

The invention has been given by way of example only, and various other modifications of and/or alterations to the described embodiments may be made by persons skilled in the art without departing from the scope of the invention as specified in the appended claims.