Patent Grant
9696041
This application is the U.S. national phase of International Application No. PCT/IB2013/054298, filed 24 May 2013, which designated the U.S. and claims priority to IT Application No. TO2012A000455, filed 25 May 2012; the entire contents of each of which are hereby incorporated by reference.
The present invention relates to devices for control of the supply of gas for appliances having one or more gas burners or similar flame generators. More in particular, the invention regards a control device having a timing function, aimed at enabling setting and/or adjustment of a desired time interval of supply of gas to a respective burner or the like.
Gas taps commonly used in cooking appliances and the like have a body, generally made of metal, provided with an inlet for connection to a gas-supply line, and an outlet for connection to a duct for delivery of the gas to the burner controlled by the tap. Mounted within the tap body are means for adjusting the flow of gas, constituted, for example, by an open/close element or partializer that can be position-adjusted via a manoeuvring rod and/or further levers or internal mechanisms. The rod projects axially from a proximal end of the tap body and is designed to turn about its own axis, for the purposes of the aforesaid flow adjustment. Coupled to the manoeuvring rod is a knob: a rotation imparted manually on the knob hence brings about rotation of the rod and consequent flow adjustment.
Provided within the tap body is a safety valve, which can be kept in the respective open condition by an electromagnet, the valve being of the open-closed type, for enabling or preventing, respectively, the flow of gas to the burner. The electromagnet is supplied via a thermo-electric generator, typically constituted by a thermocouple connected to a corresponding attachment or electrical connector of the tap body. The opposite end of the thermocouple, i.e., its sensitive part or hot junction, is installed in the proximity of the burner controlled by the tap. When the burner is lit, the sensitive part of the thermocouple generates an electromotive force (e.m.f.) in response to the heat generated by the flame to the burner, which determines a current that supplies the electromagnet of the safety valve, such as to keep the open-close element of the latter (associated to a movable core attracted by the electromagnet) in the respective open condition, countering the action of a spring.
Basically, as long as the burner is lit, the thermocouple generates a current that enables the electromagnet to keep the valve open; when the burner is turned off manually, or goes out accidentally, the electrical supply to the electromagnet ceases and the valve closes, forced in this direction by the aforesaid spring so as to prevent passage of gas between the inlet and the outlet of the tap.
For the aforesaid reasons, the rod of the tap is able to translate along its own axis, in a direction of actuation, against the action of elastic means inside the tap body. This axial displacement can be obtained by pushing the knob of the tap and turning it. With this movement there occurs both an initial opening of the safety valve and the flow of gas to the burner, and the knob is kept in the pressed condition until the flame is lit on the burner. As has been said, in the presence of the flame, the thermocouple generates the current, which, via the electromagnet, keeps the valve in the open condition. Hence, after ignition of the flame, the user can release the knob.
Operatively associated to the tap there may also be a gas-lighter system, for generating sparks in the proximity of the burner in order to cause ignition of the flame. This system usually comprises an electrical circuit that includes electrodes, generated between which are the aforesaid sparks following upon an electrical discharge. In some gas appliances, the lighter system is activated by exploiting the configuration of the tap, and especially the possibility of its rod translating axially. Consequently, by pressing the knob of the tap after turning it at least slightly, in addition to determining initial opening of the safety valve and flow of gas to the burner, the lighter system is also activated.
For this purpose, generally associated to the rod of the tap is an actuation element, which, in the course of axial displacement of the rod, causes switching of a microswitch of a normally open type, belonging to the electrical circuit of the lighter system. The microswitch may be of a type commonly available on the market for various uses and is anchored directly to the body of the tap, which has for this purpose at least one threaded hole for a corresponding fixing screw.
To a gas tap of the type referred to previously there may be associated a device for timed control of the supply of gas to a corresponding burner, i.e., to enable setting of a desired time interval of operation of the burner.
Timer devices are known, operatively coupled to a respective gas tap and having a corresponding knob, substantially coaxial to the knob of the tap. Via the knob of the device, a user can set a desired time interval of supply and then light the burner. Upon expiry of the time interval set, the device brings about closing of the safety valve inside the tap so as to interrupt supply of gas to the burner. For this purpose, the known device integrates a control circuit arrangement that basically includes timer means, which can be set via the corresponding knob, and controllable electrical switching means, connected between the thermocouple and the electromagnet of the safety valve of the gas tap. In a possible embodiment, the circuit arrangement of the known device also includes controllable electrical switching means connected in series to the circuit of the lighter system, designed to perform the functions of the microswitch previously referred to provided on taps of a traditional type.
In its general terms, the object of the present invention is to provide a control device of the type indicated having improved structure and functions as compared to the prior art, and, in particular, a device that is compact and inexpensive to produce, easy to assemble, and of contained cost, high reliability, and convenience of use.
The above and other objects still, which will emerge more clearly hereinafter are achieved according to the present invention by a control device for gas appliances, in particular appliances that comprise at least one gas tap having a safety valve that includes an electromagnet that can be supplied via a thermo-electric generator.
Preferably the control device comprises at least one from among:
The device according to the invention is distinguished by the presence of structural elements configured for improving at least one from among:
Preferential characteristics of the control device according to the invention are specified in the claims, which form an integral part of the technical teaching provided herein in relation to the invention.
Further purposes, characteristics, and advantages of the present invention will emerge clearly from the ensuing detailed description and from the annexed drawings, which are provided purely by way of explanatory and non-limiting example and in which:
In the example illustrated, the appliance 1 is a cooking appliance, and more in particular a cooking hob, of a general conception in itself known, of which just the elements useful for an understanding of the invention are represented. The timer device according to the invention may in any case also be used in other types of appliances provided with at least one gas burner, or similar flame generator, controlled via a respective tap, such as for example boilers, in particular for domestic heating.
The structure or body of the appliance 1 includes a lower box 2, which is fixed to an upper lid 3, defining a working area 4 identified in which are various cooking locations 5, as well as a command area 6. As per the known art, mounted within the structure of the appliance 1 are various functional components, amongst which—for what is of interest herein—taps for control of the supply of gas to the burners (not represented in detail herein)—of the various cooking locations 5. For this purpose, as may be noted in
By way of example, in the example of embodiment represented, only one of the taps 10 is equipped with a timer device provided according to the invention, designated as a whole by 20. Once again by way of example, the four taps 10 of
In traditional applications, as has been said, the actuation element 10f can be advantageously exploited also for causing switching in closing of a microswitch MS forming part of the lighter system, which is fixed to the body of the tap via the screw S, typically a microswitch connected to the a.c. voltage of a domestic electrical wiring system, such as a 220-V a.c. voltage.
Visible in
In a preferred embodiment, the command means 22 comprises a ring nut member or knob, which is operatively set between a knob 12 for manual actuation of the rod 11 of the tap 10 and the outer face of the wall 3a. In the assembled condition of the device 20, the command means 22—hereinafter referred to for simplicity as “ring nut”—is mounted movable, in particular angularly movable or rotatable, and is basically coaxial to the knob 12. In one embodiment (not represented), the ring nut 22 may also be axially movable, for example in order to bring about switching of control elements of the tap 10 and/or of the device 20. Of course, the shape and proportions of the ring nut 22 as represented, with respect to the knob 12, are merely indicative.
In a preferred embodiment, the ring nut 22—which can function as light guide for performing also light-warning functions—represents the only component of the device 20 that is visible and operable from outside the structure of the appliance 1. In other possible embodiments, from the outside of the aforesaid structure there may be noted at least partially also other components of the device 20, for example a light-warning element.
In a preferred embodiment, the structure of the device 20 has means for coupling the casing 21 to the body of the tap 10. In the example illustrated, the coupling means comprise a bracket 23, which is preferably made of metal or thermoplastic material and is operatively set between the casing 21 and the body of the tap 10. Advantageously, fixing of the bracket 23 can be carried out by exploiting at least one screw that is normally associated to the body of the tap 10, for example a screw used for its fixing to the structure of the appliance 1 or a screw S that, according to the known art is used for fixing the microswitch MS referred to previously (
In variant embodiments (not represented), the bracket 23 may be associated to or integrated with the casing 21, for example by overmoulding plastic material of a part of the casing 21 on the bracket 23, or shaping a part of the body of the casing 21 like a bracket, in order to perform directly functions of coupling to the body of the tap. In other possible embodiments (not represented), the casing 21 of the device may be fixed to the structure of the appliance 1, via a purposely provided bracket or else directly.
The components of
In traditional applications, as has been said, the actuation element 10f may advantageously be exploited also for causing switching in closing of the microswitch MS forming part of the lighter system. As will be seen, in a particularly advantageous embodiment of the invention, the circuit arrangement of the device 20 includes a switching means, which performs also the functions of the aforesaid microswitch MS provided according to the known art. In the case of use of the timer device according to this embodiment, as exemplified here, the traditional microswitch MS may be omitted, and the screw S normally used for its fixing (
A possible embodiment of the bracket 23 is visible in
The part 40 of the casing defined hereinafter for simplicity as “container” is substantially box-shaped and made of plastic material, with a bottom wall 40a and peripheral walls 40b that define a cavity or a seat for housing at least part of the circuit arrangement 25 and of the transmission arrangement including the transmission members 28-30, which are preferably toothed transmission members. Preferably, one of the peripheral walls 40b closes only partially the corresponding side of the container 40, thus defining a side opening 40c (
In a preferred embodiment, one of the peripheral walls 40b has an opening or gap 40e (
The casing 21 of the device 20 is configured for coupling with the body of the tap 10, and for this purpose has a passage, in which a corresponding part of the tap may be received passing through it. For example, in the embodiment illustrated, the bottom wall 40a has a through opening 42, which is preferably, but not necessarily, substantially circular. Preferably, moreover, the container 40 defines a hollow portion 42a, projecting within the corresponding cavity, where the opening 42 is located. Very preferably, moreover, the container 40 also defines an external recess, for housing partially, and with possibility of movement, the actuation element 10f of the tap 10.
In the embodiment illustrated, the bottom wall 40a and the peripheral wall 40b that has the gap 40e define together, within the container 40, the aforesaid hollow portion 42a, having an outer profile that is at least in part cylindrical. As may be seen in
With reference also to
In one embodiment, the circuit board 25a has a respective passage that surrounds at least in part the passage of the casing 21. In the example of embodiment, the passage of the circuit board 25a is in the form of an opening or slot 25b having a profile at least in part similar to or congruent with that of the opening 42 of the bottom wall 40a of the container 40 and/or of the corresponding hollow portion 42a, and the circuit board 25a is mounted in a position generally close to the bottom wall 40a. In the example, the slot 25b extends as far as an edge of the circuit board 25a and has at least a corresponding portion shaped like an arc of circumference. In other embodiments, the passage of the circuit board 25a may be circular, such as a hole, for example if the portion 42a is generally cylindrical or if it is absent.
The specific embodiment of the control circuit provided on the circuit board 25a may comprise—in general terms—the components described in WO 2010/134040, for performing the functions described in said document and/or other specific functions envisaged according to the present invention. An example of circuit will in any case be described hereinafter with reference to
In one embodiment, the circuit arrangement 25 includes light-emitting means, which may comprise one or more emitters, for example of a LED type. Preferably, these emitter means are mounted on a face of the circuit board 25a—here defined as upper face—in the proximity of the passage of the casing 21. In the example represented, a number of emitters 43 are provided, arranged at intervals apart around the slot 25b. Given that, in the example, the slot 25b extends as far as an edge of the circuit board 25a, the emitters 43 are arranged according to the profile of the arc-shaped part of the slot itself, preferably at substantially regular intervals.
The circuit arrangement 25 comprises detection or sensor means, for detecting the angular position of the ring nut 22 and supplying accordingly a signal representing a time interval of supply of the burner controlled by the tap 10. In the example, these sensor means include a stationary component 44, preferably mounted on the upper face of the circuit board 25a. In one embodiment, the sensor means are of a resistive type, such as a rotary potentiometer or trimmer, actuated by a corresponding part that may be set in rotation following upon a rotation of the ring nut.
In one embodiment, the signal for activation of the timing function of the device 20 is supplied to the circuit arrangement 25 by a control element. Preferably, this control element comprises a switching means, such as a pushbutton switch, preferably a low-power switch, in particular, for voltages ranging between 1 V and 24 V, which can be switched following upon axial displacement of the rod 11 of the tap, for example, the switch designated by 45. Advantageously, if the circuit of the device 20 is prearranged also for connection to a system for lighting the burners of the appliance 1, the signal generated by switching of the control element may also be used for governing the lighter system. In the example represented in
The motion-transmission element 27 is configured for transmitting an axial movement of the control rod 11 of the tap 10 to the switch 45, and for this purpose is mounted movable on the casing 21, in particular in a slidably way. At least one part of the motion-transmission element 27 faces the outside of the casing 21 in order to be able to interact or couple with the actuation element 10f of the tap 10. In embodiments not represented, it is also possible to provide a motion-transmission element configured for direct coupling to the rod 11.
In the embodiment exemplified, the element 27 has a base part 27a and an upright part 27b, the latter being shaped for engaging slidably in a vertical direction in the gap 40e (
In a preferred embodiment, between the control element represented by the switch 45 and the corresponding actuation element 27, the aforesaid elastic means, or damping means, are provided, in particular having the function of operating the pushbutton of the switch 45 and compensating for possible tolerances of production and assembly and/or preventing risks of excessive stresses exerted by the element 27 on the switch 45. In the embodiment exemplified, and as may be appreciated, for example, in
In embodiments not represented, the damping function can be integrated directly in the motion-transmission element, for example by providing in its body an elastically deformable part, having spring functions.
The circuit arrangement 25 of the device includes first connection means for electrical connection to the electromagnet of the safety valve of the tap 10. Once again with reference to the example of
In the example represented (see, for example,
In variants not represented, the conductors 47 may be absent, with the connector 47a connected or associated directly to the support of the circuit arrangement 25, with said connector, support, and casing of the device 20 appropriately shaped for enabling a connection to the connector 10e of the tap 10.
More in general, the electrical connectors, such as a first connector towards the electromagnet of the safety valve of the tap and a second connector towards the thermocouple, may be of the same type or else of different types: in the latter case, the timer device can function also as “adapter” between different connectors, i.e., between a thermocouple having a first type of connector and an electromagnet or safety valve of a gas tap having a second type of electrical connector, or else a timer 20 having a first connector 25d different from a second type of connector 47a.
The arrangement 25 likewise includes second connection means for electrical connection to the thermo-electric generator of the tap 10, i.e., the corresponding thermocouple. In the device 20 represented the conductors of the thermocouple—not represented—that equips the tap 10 are connected to the circuit arrangement 25a via fast-coupling connectors, which are preferably blade connectors, such as Faston connectors. In the example represented, projecting from the lower face of the circuit board 25a are two blade contacts 25d+ and 25d− (hereinafter, where not strictly necessary, designated simply by 25d), in particular of a male Faston type, which are generally L-shaped and are parallel to one another. The contacts 25d pass through the slits 40h of the bottom 40a of the container 40 so that their contact part projects outwards, as may be seen, for example, in
It will be appreciated that, in the example represented, the connection means proper to the thermocouple (here female Faston connectors) are of a different type from the connection means of the thermocouple provided by the tap (here the attachment 10e of a coaxial type): the device 20 consequently functions as “adapter”, as explained above.
Note that the contacts 25d could be replaced by a cable with two conductors provided with a connector for a thermocouple.
The circuit board 25a preferably has positioning and fixing through holes 25e, designed to couple with reliefs 401 (
In a preferred embodiment of the timer device 20, the movable part of the position-sensor means—actuated by, or including, the shaft designated by 28b—is able to rotate about an axis that is different from the axis about which the ring nut 22 turns, in particular is substantially parallel thereto, and operatively set between the ring nut 22 and the movable part of the sensor means is a transmission arrangement; i.e., the device 20 comprises a transmission arrangement, set between the control element or ring nut 22 and the position-sensor means.
In the preferred embodiment, the aforesaid transmission arrangement includes a first transmission member that is substantially coaxial to the ring nut 22 and is able to turn therewith. This first transmission member has an axial cavity, in which there may be received a corresponding part of the tap 10, and the ring nut 22 is coupled in a separable way to this transmission member.
Preferably, the transmission arrangement includes at least one second transmission member, which is engaged in rotation with the first rotating member and is able to set in rotation the movable part of the position-sensor means.
In the example represented, the transmission arrangement comprises the rotating members previously designated by 29 and with 28, which represent the aforesaid first and second transmission members, respectively.
Once again in
In a preferred embodiment, the member 28 basically comprises a gear, the axis of rotation B of which is defined by a pin 28a projecting from its upper face, said pin being designed for engagement in a respective cylindrical rotation seat 41d of the lid 41 (
Projecting, instead, from the lower face of the member 28 is a shaft 28b, coaxial to the upper pin 28a, which provides an element for actuation of the movable part of the position-sensor means. The shaft 28b preferably has a cross section that is at least in part square (not circular), designed to couple mechanically to an internal movable member of the potentiometer 44, partially visible in
In a preferred embodiment, mechanical end-of-travel means are provided for rotation of the member 28, which preferably comprise an element carried by the member itself, designed to interact with a stationary contrast element. For this purpose, in the case represented, projecting from the lower face of the member 28 is an arrest element 28c, designed to interfere with a fixed contrast element of the container 40. A contrast element of this sort is designated by 40i in
According to variants not represented, means for providing a snap coupling or engagement that defines an angular position or angular area of mechanical zero may be associated to other elements of the device, such as the ring nut 22 and/or the member 29.
The second rotating member 29 constitutes an axially hollow transmission element, which can be coupled in a separable way to the ring nut 22 and is coaxial thereto in order to turn according to the axis denoted by A in various figures, also corresponding to the axis of rotation of the stem 11 of the tap 10.
For this purpose, in the example illustrated, the member 29 comprises a circular ring gear 29a, projecting from the upper face of which are engagement elements 29b. Preferably, at least two engagement elements 29b are provided in diametrally opposite positions. Very preferably, the engagement elements 29b have a substantially cylindrical shape.
Advantageously, the transmission member 29 is rotatably supported by a corresponding portion of the casing 21, at the corresponding passage. For this purpose, in the example represented, projecting from the lower face of the circular ring gear 29a is a cylindrical annular part 29c, having a smaller circumference than the one defined by the teeth of the ring gear 29a. The cylindrical part 29c is designed to insert with minimal play or with slight interference in the through opening 42 of the bottom wall 40a of the container 40 so that it can turn therein about the axis A, sustained on the hollow portion 42a. In the assembled condition of the device 20, and as may be noted, for example, in
Coming now to
The through cavity of the member 30 preferably has a diameter greater than that of the member 29. Preferably, the intermediate member 30 has a generally annular shape, with an end face facing the upper face of the toothed member 29, in order to be able to rest at least partially thereon.
According to an advantageous characteristic, an optical guide is provided here made up of a number of parts, such as the elements 22 and 30 preferably made of transparent thermoplastic material, for transferring a light signal from the inside of the device 20 and/or of the appliance 1 to the outside of the appliance 1.
In one embodiment, the member 30 performs functions of light guide or optical guide, for transfer of light radiation generated by the emitter means 43 to the ring nut 22. In this embodiment, the member 30 and at least part of the ring nut 22 are made of a transparent material, for example methacrylate, or in any case a material that is able to transmit the light generated by the emitters 43.
For this purpose, in a preferred embodiment, the diameter at the base of the member 30 is greater than the diameter defined by the teeth of the member 29 so that a peripheral annular region of the upper face of the member 30 faces directly the emitters 43, as may be noted, for example, from
The internal surface of the member 30 defines seats 30a, in the form of axial recesses, of a shape complementary to at least part of the outer profile of the engagement elements 29b of the member 29 in order to enable mutual coupling thereof that enables transmission of a rotation of the member 29 to the member 30, as may be seen, for example, in
The lid 41 of the casing, made of plastic material, has a respective bottom wall 41a, defined in which is a through opening 41b, here circular, which forms part of the aforesaid passage of the casing 21 and inserted in which is part of the tap 10. In the example, the through opening 41b has a diameter substantially corresponding to that of the opening 42 of the container 40 and/or substantially corresponding to the diameter of the portion of tap 10 on which it is mounted. The bottom wall 41a of the lid 41 also has holes 41c for the passage of the screws used for fixing the lid and the container together and/or with respect to the bracket 23, the screws also passing between the spacer bushings 25f previously mentioned. On the internal face of the lid 41 the cylindrical seat 41d is also defined, for receiving a corresponding portion of the pin 28a of the toothed member 28. In embodiments not represented, the lid 41 and the container 40 are associated to one another and/or fixed via means different from the ones illustrated, such as means for mutual engagement of the lid and/or of the container, preferably of a snap-in type, or else fixed by gluing or welding, in particular, welding of a laser or vibration type, or by hot re-melting of a plastic material of at least one of the lid and the container. Coupling or fixing between the lid 41 and the container 40 is preferably of the sealed type, possibly with the aid of sealing elements set in between.
Projecting from the same face of the lid 41, preferably along the corresponding perimeter, are reliefs 41e, for centering the lid itself on the container 40, as well as a side wall 41f, designed to close the opening 40c of the container 40 (
In the embodiment illustrated the connector appendages or portions 40d and 41g define at least one of engagement means and polarization means, for unique coupling with the predefined connector 26. More in particular, the appendage 41g includes a tooth (see, for example,
The connector 26 is preferably provided with elastic electrical terminals or connections, designed to contact the respective electrical terminals of the connector 25c, which are preferably made in the form of electrical tracks on the circuit board 25a, but could also be constituted by rigid metal terminals. The connection of the connector 26 to the corresponding wiring may, for example, be obtained by insulator-punchthrough connection means.
In the example of embodiment provided, the ring nut 22 has an axial cavity, in which there may be received a corresponding part of the gas tap, preferably comprising at least part of the rod 11. The ring nut 22 has a gripping portion 22a, which is preferably provided on the surface with knurling or the like. The outer profile of the gripping portion 22a is preferably substantially frustoconical, with major diameter on its face opposite to the wall 3a of the appliance, and in particular with an inclination of its peripheral wall 221 (
On the opposite face of the portion 22a a seat 22b is defined for the sealing element 31, which is preferably an annular gasket, of an O-ring type. In the condition where the device 20 is installed, the element 31 is designed to co-operate in a sealed way with the front surface of the wall 3a of the appliance.
Rising from the lower face of the gripping portion 22a is a cylindrical hollow portion 22c, on the outer surface of which seats 22d are defined, in the form of axial recesses, having a shape at least in part complementary to the outer profile of the engagement elements 29b of the toothed member 29 in order to obtain mutual coupling between them that enables transmission of a rotation of the ring nut 22 to the member 29, as may be seen, for example, in
In a preferred embodiment, the end face 223 (
As has already been seen, an outer annular part of the lower face of the member 30 is set facing the emitters 43. The light radiation LR emitted by an emitter 43 impinges on the bottom face of the member 30 and then proceeds inside it in an axial direction, until it encounters the corresponding inclined peripheral wall 301. The wall 301 hence reflects at least part of the light radiation in a substantially radial direction (i.e., a direction substantially orthogonal to that of the radiation entering the body of the member 30), in the direction of the centre of the member 30.
Possibly, one or more surfaces of the components involved may be treated for improving transfer of light radiation. The various walls of the optical guide could even present angles and/or conformations different from the ones exemplified, provided that the function described is guaranteed.
The radiation propagates in the cylindrical portion 22c of the ring nut 22, fitted in the cavity of the member 30. The radiation proceeds in the body of the portion 22c in a radial direction, in the direction of the axis of rotation, until it encounters the inclined end face 223 of the cylindrical portion 22c. This face 223 now reflects at least part of the radiation within the cylindrical portion 22c, in an axial direction, until it encounters the inclined wall 222 defined at the top end of the axial cavity of the ring nut. The wall 222 then reflects at least part of the radiation again in a radial direction, now outwards, over the gripping portion 22a of the ring nut, towards its part that projects radially from the knob 12 of the tap. The radiation proceeds in the body of the gripping portion 22a until it encounters the corresponding peripheral wall 221, which reflects again the radiation in an axial direction, so that it is evident for the user.
Preferably, the outer diameter of the cylindrical portion 22c is smaller than the diameter of the opening 7 provided on the wall 3a of the appliance and only slightly smaller than the diameter of the opening 41b of the lid, in such a way that the ring nut 22 can be turned manually. The outer diameter of the cylindrical portion 22c is also slightly smaller than the diameter of the axial cavity of the member 30 so that it can be inserted therein, with the corresponding seats 22d that fit on the part of the engagement elements 29b opposite to the part that is engaged in the seats 30a of the member 30, as may be appreciated, for example, from
The intermediate element 32 also has a generally annular shape and is provided for being operatively mounted between the ring nut 22 and the knob 12, preferably at least partially in a concealed position, as may be seen for example in
In a preferred embodiment, and as may be noted in
In the example represented, the knob 12 of the tap 10 has a main part that includes a cylindrical wall 12a and a top closing wall 12b, extending from a bottom face of which is a cylindrical shank 12c, substantially coaxial to the wall 12a. Defined in the shank 12c is an axial seat 12d for receiving and engaging the rod 11 of the tap 10, with a coupling such that a rotation imparted on the knob 12 will cause rotation of the rod 11. The diameter of the axial passage of the intermediate element 32 is slightly greater than that of the shank 12c, whereas the outer diameter of the element 32 is only slightly smaller than the inner diameter of the cylindrical wall 12a of the knob. In this way, the knob 12 can also be pressed to enable axial sliding of the rod 11 of the tap 10, with the knob itself that can slide on the element 32, the latter resting on the ring nut 22.
It goes without saying that the inner diameter of the axial passage of the ring nut 22 is only slightly greater than that of the shank 12c of the knob 12 and that the inner diameters of the axial passages of the members 29 and 30 are such as to enable insertion through them of the head portion 10a (
The presence of the transmission arrangement described prevents the need to associate the manual-control means of the device directly to the corresponding sensor, thereby preventing stresses on the sensor itself and/or on the circuit board on which it is mounted. In this perspective, it is preferable, although not indispensable, for the part of the transmission arrangement to which the ring nut 22 (i.e., the member 29) is associated not to touch in any case the circuit board, but to be supported by a portion of the casing of the device projecting within its cavity (for such a case it is hence also advantageous that the circuit board has a passage for this portion of the casing).
The transmission arrangement envisaged according to the invention provides also a sort of “adapter” between a control means and the corresponding movement-sensor means, and especially between the control means here represented by the ring nut 22 and the sensor means represented by the potentiometer 44. In other words, thanks to a kinematic arrangement of the type considered, a “custom” mechanical arrangement of the device 20 and/or of the control means can be adapted to a sensor of a “standard” type available on the market.
As already clarified, the device 20 is prearranged for performing at least a function of timing of the supply of gas to the burner controlled by the tap 10, and includes for this purpose at least a timer circuit and a means for manual setting of the supply interval, here represented by the ring nut 22, which can be operated from the outside of the structure of the appliance and is substantially coaxial to the knob 12 of the tap 10. In one embodiment, such as the one described previously, the knob 12 and the ring nut 22 can be turned by a user, preferably independently of one another, about the axis A, in order to enable, on the one hand, adjustment of the flow of gas admitted to the burner and, on the other hand, setting of the time of supply of the burner. The knob 12 is also axially movable, unlike the ring nut 22 (on the other hand, as has been mentioned, in possible variant embodiments also the ring nut 22 could translate axially).
As represented schematically in
The timer circuit MC can be obtained in any known way, for example including, in the circuit arrangement 25, a commercially available microcontroller provided with clock or timer function, which can preferably be supplied with a low d.c. voltage (for example 3-12 Vdc) via a supply stage or stabilized power supply. Hence, the device 20 is preferably a low-voltage device. The aforesaid microcontroller MC, in which the program or software for control of the device can be implemented, is connected in signal communication to the position-sensor means, here represented by the potentiometer 44, from which the information regarding the time interval set is obtained.
The first switching means Q1 preferably include at least one switch that can be controlled for opening or varying the electrical circuit of the thermocouple TC, when the time interval in which the burner 5a is to remain lit set via the ring nut 22 has elapsed. The controllable switch may be of an electro-mechanical type, for example a relay, or else of an electronic type, for example a MOSFET, and is preferably, but not necessarily, of a normally open type, switchable via a pulse or signal governed by the timer circuit MC. In a preferred embodiment, the switch Q1 is an electronic switch, in particular a MOSFET with extremely low channel resistance, set in series to the thermocouple TC-electromagnet EM circuit. A switch of this sort guarantees, in the case of conduction, an extremely low resistance of the circuit and enables requirements of miniaturization to be met.
According to possible variants, the switching means may include a device or circuit configured for varying the electrical circuit of the thermocouple, for example a load (such as a resistance), which when rendered active, reduces the current to the electromagnet EM.
As has been said, in a preferred, albeit non-exclusive, embodiment of the invention, the device 20 is also prearranged for the purposes of control of a lighter system. The circuit part regarding the lighter system can be obtained in any known way, and is not necessarily implemented in the circuit arrangement 25.
In a variant embodiment not represented, the circuit arrangement 25 of the device can include second control means or controllable switches, which are preferably of higher power than the first switching means Q1, in particular for a 220-V mains supply voltage, in order to control directly a lighter module (for example, for connecting in series two terminals thereof). Also these further switching means, which are preferably of a normally open type, are switchable via a pulse or signal generated by the arrangement 25.
The potentiometer 44, or other component that stands in for it, basically has the function of detecting the position, among a plurality of possible positions, assumed by the manual-control means represented by the ring nut 22, this position representing the duration of the time interval set. As has been said, in a preferred embodiment, the stationary component 44 is constituted by a rotary potentiometer, in particular of a resistive type, preferably of the type designed to be mounted and/or welded directly on a circuit board 25a, such as a commercial trimmer, but its functions may be evidently obtained via other electrical and/or electronic components, such as for example optical or magnetic encoders and sensors. The person skilled in the branch will hence appreciate that the actuation element of the sensor means do not necessarily have to be represented by a rotary shaft, such as the shaft 28b, it being possible to obtain it with some other type of movable element.
In the example described previously, the emitters 43, which are preferably distributed in a circle around the head portion of the tap 10, bring about lighting-up of the ring nut 22, which is made of transparent plastic material, or in any case a material designed to function as light guide. Also other mechanical parts for transmission of the rotational movement—at least the intermediate member 30 and preferably also the toothed member 29—are preferably made of a similar material, for example polycarbonate, in order to function as optical guide. In this way, the light generated by the emitters 43 is visible from outside the casing 21. The light warnings, generated by the emitters 43 under the control of the timer circuit MC are useful for a user of the device 20. For example:
As already mentioned, in addition or as an alternative, there may also be provided warning means of some other type, for example of an acoustic type, such as the buzzer BZ. In such a case, for example, different acoustic signals may indicate different events, such as confirmation of programming, approach of expiry of the supply time set, effective end of the supply time set.
The control element, here represented by the switch 45, of the circuit arrangement 25 basically has the function of generating the command signal that the microcontroller circuit MC handles for determining or controlling initial closing of the switch Q1 and start-up or otherwise of a time count. The signal generated by the switch 45 can also be used by the arrangement 25, and, in particular, by its microcontroller MC, for generating the switching pulse of the control means associated to the circuit of the lighter system.
Assembly of the device 20 is very simple. Once the casing 21 has been assembled on the bracket 23, the latter is fixed to the body of the corresponding tap 10, already mounted on the part 2 of the structure of the appliance 1. The head portion 10a of the tap is thus inserted in the through opening of the casing 21, with the actuation element 10f of the tap that is located in a position corresponding to the recess 42b of the container 40 (see, for reference,
The connector 47a is connected to the corresponding attachment 10e of the tap, whereas the conductors of the thermocouple TC are connected to the blade contacts 25d (
General operation of the device may be at least in part similar to the one described in the document No. WO 2010/134040, to which the reader is referred. In brief, for the purposes of programming of a desired time interval in which the burner 5a is to remain lit, the user has to turn the ring nut 22 for setting the desired time, for example ranging between 1 and 120 minutes. The user then turns the knob 12 and presses it in order to bring about initial opening of the safety valve and activation of the gas lighter. The pressure exerted on the knob 12 causes axial displacement of the stem 11 and of the actuation element 10f, and hence movement of the motion-transmission element 27, with consequent switching of the control element represented by the switch 45. The signal generated by the switch 45 is used by the control logic of the device 20 for controlling closing of the switching means Q1 provided on the circuit arrangement 25, connected in series between the thermocouple TC and the electromagnet EM of the safety valve, in order to start counting of the time and generate the command signal of the switch associated to the lighter system, when this function is envisaged. Once the burner 5a has been lit, the heat generated by the flame causes the thermocouple TC to generate the current necessary to keep the safety valve of the tap 10 open.
At the end of the time interval set via the ring nut 22, the control logic generates a new signal of switching of the switching means Q1, which in this way open the circuit of the electromagnet EM, with consequent closing of the safety valve of the tap 1. The burner is thus turned off once the pre-set time has elapsed.
The device 20 preferably has a predefined position of non-intervention in order to enable normal use of the tap 10 and of the corresponding burner without activation of the timing function. This position may conveniently be represented by an angular position of “zero” of the ring nut 22, which will be purposely provided with suitable indications. When the ring nut 22 is in this position, detected via the transmission arrangement 28-30 and the sensor 44, the functions of the circuit that are associated to the time count will not be active. However, pressure on the knob 12 will cause, in the ways already described above, generation of the signal that determines closing of the switching means in series between the thermocouple and the electromagnet in order to guarantee the electrical continuity necessary for opening the safety valve, and/or will cause generation of a signal for control of the lighter module.
In a different embodiment, the control logic of the device 20 envisages that programming will be carried out by the user after the flame to the burner 5a has already been lit. In this case, the user has to carry out lighting of the burner in the way described above (turn the knob 12 and press it, with consequent switching of the switch 45 and activation of the lighter system). Following upon ignition of the flame, the device 20 is activated in a programming mode, signalled, for example, by a fast flashing of the ring nut 22. Next, if within a given time interval the user does not turn the ring nut 22, the supply of gas proceeds in a traditional way (i.e., without timed turning-off), for example with the ring nut 22 lit up continuously via the emitters 43. Instead, in the case where it is desired to program the device 20, the user turns the ring nut 22 and then presses the knob 12 as a confirmation of programming; in this case, the device can signal confirmation of programming (for example, acoustically or with a fast flashing of the ring nut) and start-up of the countdown (with flashing of the ring nut that, for example, becomes slower).
The flowchart of
Block 101 is the starting block and highlights the condition of flame off and device 20 not programmed, i.e., in a quiescent state. Block 102 represents the step of ignition of the burner, which can be obtained by turning and pressing the knob 12 of the tap 10: rotation enables an initial flow of gas to the burner, whilst pressure exerted on the knob brings about switching of the switch 45, preferably activating a lighter module. Block 103 represents the condition of flame lit on the burner, following upon which the device 20 is activated or can be activated in a programming mode. In a possible embodiment, activation in said mode is determined by switching of the switch 45 (block 102), detected by the control circuit of the device 20. In a preferred embodiment, passage to the programming mode is determined by detection of the effective ignition of the flame, inferred, for example, from the signal generated by the thermocouple. Activation in the programming mode is signalled to the user, for example via a fast flashing of the emitters 43, which can be detected on the ring nut 22. Block 104 is a testing block, with which a check is made to verify whether the user has carried out, within a given time, programming of the device 20 by turning the ring nut 22 beyond the zero position. If he has not (output NO), control passes to block 105, with which the warning mode changes state, for example with the emitters 43 lit up continuously, and then to block 106, with which supply of gas to the burner is made to proceed in a normal way, i.e., without there being established a time of forced extinction. Otherwise (output YES from block 104), control passes to block 107, for detecting the extent of the angular movement of the ring nut 22, and hence the time set by the user, with corresponding indication. The user then confirms programming (block 108), by applying a brief pressure on the knob 12 of the tap, detected by the circuit of the device 20 via switching of the switch 45. Control passes to block 109, for confirmation and notification that programming has been carried out. The notification may be of a visual type, via suitable flashing of the ring nut, and/or acoustic type, if the device is provided, for example, with a buzzer. Control then passes to block 110, with which the timer circuit MC starts countdown of the time of supply of the burner, preferably with a change of state of the warning light, for example, a slow flashing of the emitters 43. Block 111 expresses the fact that a time of forewarning of end of supply of gas to the burner has elapsed, which may depend upon the total time set via the ring nut 22. Once this time of forewarning has elapsed a visual and/or acoustic warning is issued, for example a fast flashing of the emitters 43 and/or a series of frequent beeps generated by the aforesaid buzzer (if present). Control then passes to block 112, which is a testing block, where a check is made to verify whether the user wishes to prolong supply of gas to the burner, via rotation of the ring nut 22 (and/or brief pressure applied on the knob 12). If he does not (output NO), control passes to block 113, where, at the end of the time set via the ring nut 22, the device issues a command for switching of the switching means Q1, causing connection between the thermocouple TC and the electromagnet EM to cease and consequently turning off the flame. Preferably, there is also issued a suitable visual and/or acoustic warning, for example a continuous flashing of the emitters 43 and/or two prolonged beeps separated from one another (if the buzzer is envisaged). The device 20 then sets itself in a quiescent state.
In the case where the user prolongs the supply time (output YES from block 112), control passes to block 114, in which a brief pressure exerted on the knob 12 (and/or rotation of the ring nut 22) is detected. In block 115 the warning for activation of the programming mode is issued, such as a fast flashing of the emitters 43, and the device remains in the wait state, for a given time interval, awaiting further confirmation of programming, for example obtained with a brief pressure exerted on the knob 12 of the tap, detected in block 116. Control then returns to block 109, for confirmation and notification that reprogramming has been carried out.
It is clear that numerous variations may be made by a person skilled in the art to the device described by way of example, without thereby departing from the scope of the invention as defined in the annexed claims. The various characteristics of the various examples may be combined at least in part together to form devices that may even be different from the ones represented and described by way of non-limiting example.
The coupling part 23 preferably includes at least one member 23g for engagement to the body of the tap 10, in particular in an area of the rear portion 10b of the tap. The engagement member 23g may include, as in the example, an elastically deformable tab, defined on which is a tooth (visible in
As has been said, in the case exemplified in
For this reason, at least one of the casing of the device and at least an internal element of the device and/or of the transmission arrangement of the device is configured for enabling a convenient accessibility to said member 10i, for example via a screwdriver or similar tool.
Preferably, part of the casing, for example at least its lid 41, can be configured for this purpose. In the non-limiting example illustrated, and as may be seen in
As may be appreciated, for example from
For example, starting from the assembled condition, and in the case where it is necessary to carry out an adjustment of the member 10i, the operator simply has to bring the ring nut 22 into the corresponding zero position, where the recesses 29d and 30b of the members 29 and 20 are axially aligned to the screw member 10i. Next, the knob 12 of the tap 10 and the ring nut 22 can be removed, as illustrated in
In other embodiments (not represented), a passage aimed at enabling access to a member for adjustment or calibration of the gas tap may be defined in some other position, not necessarily coinciding with the passage 42, for example a circular passage, involving, for example, also the circuit board 25a and/or the member 28. In one embodiment, the body 40 and the lid 41 may be shaped so as to have two tubular elements facing the inside of the casing 21, which fit to their facing ends to form a single passage duct, preferably a closed duct inside the casing 21, for reasons of protection and/or hermetic seal. In such an embodiment, the circuit board 25a can have a through hole in a position corresponding to one of said tubular elements.
Of course, the variants described with reference to
In the embodiments previously exemplified, to one and the same control element 45 there are associated both activation of the lighter system, and the functions of the device 20 linked to timing, but it is clear that even a number of control elements may be provided, such as two separate contacts or switches. In such a variant, for example, the control element connected to the timing can be switched via the ring nut 22, which in this case will be mounted axially movable. As already mentioned, moreover, the device 20 may not perform functions linked to lighting of the burner.
Previously reference has been made to the use of control means, amongst which the switch Q1, designed to modify the state of the electrical connection between the electrical-connection means 47 and 25d, i.e., to open the thermocouple-solenoid electrical circuit when the time interval set via the ring nut 22 has elapsed. As has already been mentioned, according to possible variants, the control means may be prearranged for modifying the state of the connection referred to above, without necessarily opening the aforesaid circuit, but simply varying it (for example, by inserting in parallel to the thermocouple a load or a resistance that reduces the current to the solenoid).
In the embodiments described previously, the means for detecting the movement of the ring nut 22, associated to the transmission arrangement, are represented by a rotary potentiometer or trimmer, but in possible variants it is possible to provide a linear potentiometer, with a movement of the corresponding movable part along a respective axis, in particular orthogonal to the axis A, for example envisaging a pinion-and-rack transmission system. The rotary potentiometer previously described has a seat engaged in which is the element 28b of the member 28, whereas in the case of a linear potentiometer this would preferably have a slider in relief, operatively coupled—for example—to a rack element engaged to a toothing of the member 28, which functions in this case as pinion.
As an alternative to what has been explained previously, the device 20 could even comprise only just some of the parts or functions described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| TO2012A0455 | May 2012 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2013/054298 | 5/24/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/175438 | 11/28/2013 | WO | A |
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| Number | Date | Country | |
|---|---|---|---|
| 20150153047 A1 | Jun 2015 | US |
