Patent Description:
Such temperature control devices comprise: water heating means; a control device that regulates the temperature around a target value that may be set by the user with at least one knob or equivalent means.

Hereinafter, "user regulation" indicates the setting of the target temperature that may be performed by the user and "thermostatic control" the on/off control of the heating elements by the thermostat.

In order to explain more clearly the state of the art in the field of the invention, hereinafter the <FIG>, <FIG> and <FIG> are used without any limiting or omitting intent of the prior art.

Traditionally, according to the most widespread state of the art, said temperature control devices use the electromechanical technology in which the thermostatic control is carried out with a "mechanical thermostat" with thermostatic control function ("thermoregulator thermostat" or "thermoregulator") and the temperature setting may be achieved with a manual setting means accessible to the same user and mechanically coupled to said thermostat. Said mechanical thermostat is connected with known means, for example two faston connectors, to the heating elements and to the temperature probe (see <FIG>).

By "user interface" it is meant the set of input or output elements with which the user may interact: such manual setting means and possibly equipped with indicator lights or buttons for other functions.

Following the European Energy Efficiency Regulations, intelligent algorithms have been developed that allow reducing the consumption and require control based on a microcontroller, this has led to the progressive spread of electronic devices in replacement of the mechanical ones.

In the electronic models, the mechanical thermostat for the thermostating function is replaced by an electronic thermostat <NUM> (controlled, for example, by a microcontroller), which:.

The actuators and sensors <NUM> are part of an "actuation block", which is connected to the tank <NUM> in a precise position, in particular very advantageously it is connected to a flange <NUM> (<FIG>); said flange comprising at least the openings in which the heating resistances <NUM> and a sheath <NUM> for the temperature sensors <NUM>, are inserted, the design thereof may be similar or identical to the previous one of the electromechanical technology.

The means for connecting the actuation block in a precise position may coincide with electric connectors <NUM>. b at least when these are female/male faston couplings <NUM>.

The temperature setting function is now accessible to the user because it is implemented through an interface board <NUM> whereon the input output components <NUM> are mounted in an easy-to-access section of an external cap <NUM>. According to the prior art, the input output components <NUM> send at least one input signal by means of an electromechanical transducer such as for example an encoder, a potentiometer or a trimmer, located on the interface board. Hence, the input output components <NUM> are mechanically coupled with electromechanical components mounted on the board.

Said user interface board <NUM> also houses the connectors for the power supply and connection cables <NUM> at least to the actuation block and may house buttons or lights.

The electronic thermostat comprising the microcontroller (or equivalent electronic means) may be placed:.

In both solutions there are two electronic assemblies: one comprising at least the components of the user interface such as a transducer <NUM>, fixed to the cap <NUM> and one comprising at least actuators and sensors, constrained to the tank <NUM> with the disadvantage of having to duplicate casings, fastening means, electrical power supply with cables <NUM> and relative connectors and finally specific steps for the assembly of the product.

Said electronic assemblies may also create sturdiness and reliability problems over time as they are subject to possible damages or short circuits resulting from humidity, dust, vibrations (for example, during transport). These are criticalities that increase with the increase of as the fastening means needed the surface of the electronic board to be protected.

Such duplication also increases the critical components and makes the architecture and assembly more complex.

Document <CIT> describes a thermostat in which, in order to avoid duplication or use of wiring, the user interface and the actuation block are integrated in a single electronic board; according to this solution, the connectors of the board for sensors and actuators engage directly on the reciprocal connectors placed on the flange. Then the board is mechanically constrained to the flange. Since the same board also serves as a user interface, it is also mechanically constrained to the input output elements <NUM> which must be in a position accessible to the user. It follows that with this thermostat the position of the user interface is constrained with respect to the position of the flange and that limits the freedom in the design, requires diversifying the board to obtain models that have only aesthetic differences and requires strict mechanical tolerances between the part of the outer casing housing the user interface and the flange.

Document <CIT> describes a particular mechanical coupling between the temperature selector in which an external toothing, with crown section, constrains the rotation angle of the selector in order to limit the maximum temperature setting; the toothing is made so that it may be broken during use to eliminate the constraint on the maximum temperature. This expedient addresses the issue of energy saving and not the problem of the mechanical constraints set on the water heater by the need of coupling a user accessible mechanical selector to elements of an electronic board and where the electronic board:.

Document <CIT> describes a water heater where an electronic board is provided right behind the user interface area, as shown in figure <NUM> and electrical wires provide the connection between the heating elements and the temperature sensors on one side and the control board (control box) on the other side.

Document <CIT> describes a water heater where the temperature input knob is mounted on the cover plate in a position accessible to a user and is to be coupled to a mechanical thermostat, the mechanical thermostat is fixed to a wall of the tank, said wall and the water heater cover plate are not directly connected but separated by a layer of protective jacket. So there is one degree of tolerance between the mechanical thermostat and the knob. The coupling problem is solved by a tight coupling, made possible by a joint that permits a connector shaft to be rotatable and transmit a rotation to stub shaft that is angularly misaligned, but it requires a tight coupling between members of the kinematic chain, so the coupling is not easy to assemble and it is not designed to compensate for more than one degree of misalignment.

The document <CIT> describes a wearable night vision system comprising rotary encoders. The rotary encoders are configured to turn and slide within cylinders, thanks to internal protrusion in the cylinders, small interferences are produces when the shafts rotate in the cylinders. The interferences are not an effect of design tolerance, on the opposite they are obtained on purpose to generate a tactile feedback on the user of the device. The mechanical design is therefore very precise and the rotary selector is not subject to any particular mechanical stress nor tolerance.

Document <CIT> describes a knob coupled to the shaft of a rotary potentiometer and comprises a pressure operated switch which is completely decoupled from the potentiometer. The knob is hollow so it can contain in addition to the pressure operated switch light conductive guides. The knob is mounted directly on top of the electronic board and the coupling between knob and transducer does not deal with any specific tolerance issue.

The main purpose of the present invention, in said apparatus for controlling the water heating temperature of a storage water heater, is to resolve these drawbacks and eliminate at least in part the mechanical constraints between the portion of the interface that is accessible to the user and the components that are constrained to the flange; an additional purpose is to reduce connections that are critical for robustness and reliability.

A further purpose, at least of some variants of the invention, is to reduce the components and simplify the assembly of said device.

These and other objects, which shall become clear later, are achieved with an invention according to claim <NUM>.

Other objects may also be achieved by means of the additional features of the dependent claims.

Further features of the present invention shall be better highlighted by the following description of a preferred embodiment, in accordance with the claims and illustrated, purely by way of a non-limiting example, in the annexed drawing tables, wherein:.

Any spatial references, unless otherwise indicated, refer to how the objects are represented in the figures.

The features of a preferred variant of the invention are now described using the references in the figures. It is noted that the above figures, although schematic, reproduce the elements of the invention according to proportions among their spatial dimensions and orientations that are compatible with a possible embodiment.

According to the prior art, the connection by wiring adapts to the geometry of the system characterised by a wide mechanical tolerance between the actuation block and the selector, wherein the actuation block is constrained to the flange <NUM>, the flange is constrained to the tank <NUM>, the tank <NUM> is in turn constrained in a casing <NUM> a cap <NUM> in which the selector <NUM> is positioned.

According to the invention, the problem is solved by integrating the electronic assemblies in a single device, i.e., said thermostat with regulation <NUM> and this is made possible by a new kinematic chain actionable to regulate the temperature that overcomes the technical difficulties of the prior art.

The thermostat with regulation <NUM> according to the invention comprises, (see in particular the Figs. from <NUM> onwards):.

Said kinematic chain <NUM> comprises at least one disengageable coupling so that the assembly and disassembly of said selector <NUM> with respect to the dragged element <NUM>, <NUM> may take place. Preferably, the disengageable coupling is that between said selector <NUM> and said dragged element <NUM>, <NUM>.

Preferably said dragged element <NUM> may in turn be a kinematic sub-chain composed of at least two mutually coupled parts <NUM>, <NUM> of which a first part <NUM> couplable to said selector <NUM> and a second part <NUM> couplable to said electromechanical transducer <NUM>.

Said thermostat with regulation <NUM> may have various dimensions, external shapes, mechanical constraint means and various electrical connections such as to be able to adapt and be positioned to previously available connection points in the flange <NUM> by means of said connectors <NUM> which may be the faston connections <NUM>. a of one of the powered electrical resistances; as long as use of the thermostat with regulation <NUM> does not prompt possible advantageous design modifications of the tank <NUM> and of the flange <NUM> of the water heater wherein it is mounted in place of electronic board models of the prior art <NUM>.

Said kinematic chain <NUM> therefore provides a dragged element <NUM> or at least two mutually coupled elements <NUM>, <NUM> that allow a controlled movement compatible with foreseeable assembly tolerances.

The described kinematic chain has the following advantages:.

Such sturdiness and lack of transmission of critical stresses is obtained by providing, between the cap <NUM> and the electromechanical transducer <NUM>, at least a pair of mutually coupled elements, with a "slack"-type coupling, i.e., a coupling that can accept a clearance compatible with those that are normal manufacturing and assembly tolerances of the elements involved, such as for example, those due to shifts or inaccuracies of the relative distances with respect to the design theoretical ones, but sufficient to transmit to the dragged element <NUM> the dragged and/or translatory movement (the latter not exemplified in the Figures) whichever is needed based on the design of the selector <NUM> and the electromechanical transducer <NUM>. The object is to have sufficient clearance to avoid unwanted stresses and deformations to the elements of the kinematic chain following the selector <NUM> which imparts their movement.

Said clearance may be provided between any two consecutive elements, while the remaining couplings in the kinematic chain <NUM> are preferred to be designed with tight mechanical tolerance, also for the stability of the assembly.

According to a possible solution, said slack coupling may be obtained with a sufficient clearance between the selector <NUM> and the cap <NUM> whereon it is slidingly or rotatably mounted. A simple but not preferred solution because the user would perceive the clearance as a rough execution and may also transmit harmful efforts along the kinematic chain <NUM>.

Therefore, it is preferred that the coupling between the selector <NUM> and the dragged element <NUM> is of the slack type, i.e., that the coupling between the selector <NUM> and the dragged element <NUM> is both of the disengageable and slack type.

Hereafter, the face of selector <NUM> opposite the user will be referred to as "interior" <NUM>, and "exterior", the face towards the user; at least the following couplings are possible between the selector <NUM> and the dragged element:.

In the preferred solution, the selector <NUM> is a rotatable knob <NUM> with a slack female/male shape coupling where said selector <NUM> has a "cavity" <NUM> in the interior <NUM>, adapted to engage one end of the dragged element <NUM> which in this solution is substantially a pin, free to rotate with said selector <NUM> and whose opposite "dragging end" <NUM> is inserted in said electromechanical transducer <NUM>, which is of the rotatable type, so as to transmit to it the rotation angle of said selector <NUM>. For example, said cavity <NUM> may constrain a "fin" <NUM> to rotate integrally with said selector <NUM>. Said fin <NUM> is obtained at one end of the dragged element <NUM> and it is oriented radially with respect to the rotation axis of the dragged element <NUM>. Therefore, said fin <NUM> has a lever function that facilitates the rotary movement of said dragged element <NUM>.

Advantageously, said dragged element <NUM> may be composed of two parts mutually couplable with each other whereof a first part <NUM> has a dragged end that may be coupled with said selector <NUM> and a second part <NUM> has the dragged end <NUM> that may be coupled with said electromechanical transducer <NUM>. The realization with two distinct parts couplable with and constrainable to each other <NUM>, <NUM> allows varying only the first part <NUM> coupled with the selector <NUM> according to the geometry of the selector <NUM>, so that the thermostat board <NUM> may be used on different models of water heater <NUM>.

The first part <NUM> dragged by said selector <NUM> may be a "lug" <NUM> wherein the fin <NUM> is obtained, the second part a "pin" <NUM> which in turn has a dragged end couplable with said lug <NUM>. By lug it is meant a crown element in which the central cavity has dimensions suitable for inserting therein said pin <NUM>, determining a shape coupling sufficiently tight so as not to allow slidings of the pin <NUM> with respect to the lug <NUM>. In this solution, the lug <NUM> and in particular the length of the fin <NUM> may be made in different versions to adapt to selectors <NUM> with different geometries. Furthermore, said pin <NUM> or said lug <NUM> may have different heights to compensate for different distances provided between the thermostat board <NUM> and the selector <NUM>. Advantageously, such variabilities between models are compensated for by the geometry of the lug <NUM>. Nothing prevents the selector <NUM> from using knobs with a different geometry of the external part and the unvaried geometry for said cavity <NUM> in the inner part.

The dragging end <NUM> of said dragged element <NUM>, <NUM> is suitably shaped to couple with said electromechanical transducer <NUM>. For example, said dragging end <NUM> inserts into said electromechanical transducer <NUM> with a shape coupling.

As said, the thermostat board <NUM> is preferably protected by a casing comprising at least a covering half-shell <NUM>, which provides a suitable "opening" <NUM> in which said pin <NUM> is inserted on the side of the dragging end <NUM> being thus capable, if needed, to act also as a guide and/or support of said pin <NUM>. Advantageously, said pin <NUM> may have one or more "arms" <NUM> adapted to form a mechanical constraint that prevents said pin <NUM> from coming out of said opening <NUM> once it has been inserted therein. For example, said arms <NUM> may have a termination with an elastic snap-wise coupling. Advantageously, the length of said arms <NUM> is such that the elastic coupling snaps when the end <NUM> of the pin <NUM> is correctly inserted for a length sufficient for the mechanical coupling to transmit the movement to the electromechanical transducer <NUM> but less than that which could determine critical interferences with said transducer <NUM> or with the supporting printed circuit. Said electromechanical transducer <NUM>, as known, may be of the trimmer type, with an allowed travel interval for its movable part, stresses beyond said interval may lead to breakage.

In the event that the selector <NUM> is a knob and the dragged element <NUM>, <NUM>, in particular the dragging end <NUM>, makes a rotary movement in the opening <NUM>, it is advantageously possible to provide mechanical stop means which constitute movement end stop means for the pin <NUM>, <NUM>; these may be a "curved projection" <NUM>, that increases the radius of said pin <NUM>, <NUM> for a first arc α, and an "end stop" <NUM> that describes a second arc β along the edge of said opening <NUM> such that the sum of said first arc α and said second arc β is equal to the complementary angle with respect to the travel angle of said electromechanical transducer <NUM>. This expedient prevents mechanical stresses that may cause the same electromechanical transducer <NUM> to break.

Not illustrated in the figures, it is also possible to provide the already said translational rather than rotary movement of the selector <NUM> along guides in the cap <NUM>, if the electromechanical transducer <NUM> is a trimmer of the slider type. A slack coupling may be provided between the selector <NUM> and the dragged element <NUM> and possibly a rocker arm with relative support means for the transmission of the translatory motion.

Also in the case of translatory motion, it is possible to provide an end stop <NUM> made with mechanical stop means which blocks the movement of said dragged element <NUM> before it brings the movable part of said transducer <NUM> beyond the allowed movement range thereof.

Thus, a thermostat with regulation <NUM> is made which receives the signals from the temperature sensors <NUM> and from a selector <NUM> which enables to set the target temperature.

The user interface may also provide one or more indicator lights, (for example LEDs) that may be mounted on the thermostat board <NUM> and are visible through a window of the user interface. The light of the indicator lights may be guided from the origin to the user interface along a light guide (i.e., wave guide) which may also provide curves; therefore there are no particular constraints between the relative positions of light origin and the transparent window located on the user interface.

This flexibility in the type of mechanical and optical coupling enables not only the use of the thermostat with regulation <NUM> in new water heater models <NUM> with interfaces of different geometry of the knobs and/or more display elements, but also the replacement in models already in production.

The invention also enables a fast and robust assembly method, which includes, by way of an example, the following steps for the variants that include the components listed below:.

It is possible to carry out the step f) of mounting the lug <NUM> on pin <NUM> even before step c), in this case it is preferable to make an interlocking coupling between the lug <NUM> and pin <NUM> so that once the lug <NUM> and the pin <NUM> are coupled they remain joined.

Claim 1:
Thermostat with regulation (<NUM>) for controlling an electrical water heating element (<NUM>) for a storage water heater (<NUM>), the storage water heater comprising a flange (<NUM>), the flange (<NUM>) configured to be constrained to a tank (<NUM>), the tank (<NUM>) configured to be constrained to a casing (<NUM>), the casing (<NUM>) constrained to a cap (<NUM>), the cap (<NUM>) being coupled with a selector (<NUM>) of a target temperature for water in the storage water heater (<NUM>), the thermostat with regulation (<NUM>) configured to be constrainable to the flange (<NUM>) supporting the electrical water heating element (<NUM>), the thermostat with regulation (<NUM>) comprising:
- an actuation block in turn comprising at least connections to a temperature sensor (<NUM>) and at least an actuator for the heating element (<NUM>),
- the selector (<NUM>),
- a microcontroller adapted to:
- receive an input from the selector (<NUM>) of the target temperature for water in the storage water heater (<NUM>), by means of an electromechanical transducer (<NUM>), the electromechanical transducer (<NUM>) being one of an encoder, a potentiometer or a trimmer,
- receive a signal from the at least one temperature sensor (<NUM>),
- control the at least one actuator,
and comprising integrated in a single device:
- the connections to the at least one temperature sensor (<NUM>);
- a thermostat board (<NUM>), in turn comprising:
- electronic means for the control of the temperature for water in the storage water heater (<NUM>);
- at least one electrical connector (<NUM>.b) for the power supply of said heating element (<NUM>);
- fastening means (<NUM>.b) to the flange (<NUM>),
- the electromechanical transducer (<NUM>),
characterised in that the thermostat with regulation (<NUM>) further comprises:
a kinematic chain (<NUM>) connecting the selector (<NUM>) to the electromechanical transducer (<NUM>), the kinematic chain (<NUM>)
starting from the selector (<NUM>), configured to engage a dragged element (<NUM>; <NUM>)
continuing with the dragged element (<NUM>; <NUM>) which is couplable with said electromechanical transducer (<NUM>) with which the kinematic chain (<NUM>) ends wherein the kinematic chain (<NUM>) comprises a slack and disengageable coupling comprising a clearance between the selector (<NUM>) and the dragged element (<NUM>; <NUM>).