Patent Description:
Examples of thermostatic heads comprising the features of the preamble of claim <NUM> are disclosed in <CIT> and <CIT>.

As is known, a thermostatic head is a thermoregulation element connectable to a thermostatic valve, which is a control valve having the function of regulating the flow of hot water of a heating system inside a radiant element (such as a radiator) and the resulting exchange of thermal energy of the radiant element with the environment in which it is installed.

The thermostatic head comprises a base body defining an axis and connectable to the thermostatic valve (for example via a ring nut, a quick coupling or a bayonet coupling), a knob rotatable with respect to the base body and operable by a user, and a thermostatic bulb placed inside the knob and communicating with the environment via slots present on the knob.

The bulb internally comprises a thermosensitive medium, via which it exerts a thrust on an actuation element of the thermostatic valve to vary the flow of hot water as a function of the room temperature.

In addition to allowing the aforementioned fluidic communication of the bulb with the environment, the knob also allows a pre-regulation temperature to be set, as it is helically coupled (via a thread) to the base body. Therefore, a rotation of the knob, by the user, simultaneously results in an axial movement thereof. Since the bulb is rigidly coupled to the knob, it also rotates and moves in axial direction. In other words, the knob and the bulb roto-translate together with respect to the base body.

Axial movement of the bulb is desirable, as it defines a starting position (moving it axially towards or away from the base body) which allows the pre-regulation. In particular, the lower the pre-regulation temperature selected by the operator via rotation of the knob, the smaller the axial distance between the bulb and the base body (and thus between the bulb and the thermostatic valve), the lower the flow of hot water to the radiant element.

Vice versa, axial movement of the knob is not desirable, as it modifies the aesthetics and the geometry of the thermostatic head, increasing or reducing its external dimensions.

Rigid coupling between the bulb and the knob also involves disadvantages from a constructive and logistical point of view, linked to the fact that thermostatic heads "customized" for different customers are produced in a same production line. Customization of the thermostatic head is typically concentrated on the knob, which can have different shapes and dimensions, and have on an outer surface thereof various distinctive marks (for example obtainable via laser treatment).

Assembly of the thermostatic head comprises a first step in which the bulb is inserted inside the knob and fitted thereto (for example via a ring nut). Subsequently, a thrust transmission element is inserted. Finally, the base body is coupled to the knob.

Therefore, in order to start the assembly cycle of the thermostatic head, it is necessary to already have the customized knob. Furthermore, a large number of different components must be managed from the start of the assembly cycle, due to the plurality of possible knobs.

A purpose of the present invention is to provide a thermostatic head which can overcome the above problems.

The aforementioned purpose is achieved by a thermostatic head as claimed in claim <NUM>.

For a better understanding of the present invention, a preferred embodiment is described below, by way of nonlimiting example and with reference to the accompanying drawings, wherein:.

With reference to <FIG> and <FIG>, there is indicated by <NUM> a thermostatic head according to the present invention. The thermostatic head <NUM> is configured to cooperate with a flow control valve (not illustrated) in a heating system. The valve is conveniently of the normally open type, i.e. it is provided with a return spring that maintains it in open condition in the absence of external actuations.

The thermostatic head <NUM> comprises a base body <NUM> provided with connection means <NUM> to the valve, a knob <NUM> rotoidally coupled to the base body <NUM>, a bulb <NUM> inserted into the knob <NUM>, an intermediate body <NUM> interposed between the base body <NUM> and the bulb <NUM>, and motion transmission means <NUM> at least partially inserted into the base body <NUM> and into the bulb <NUM>.

The base body <NUM> (<FIG>) is substantially cylindrical and comprises an outer cylindrical wall <NUM> of axis A and an inner cylindrical body <NUM>, coaxial to the cylindrical wall <NUM> and connected thereto by an axially intermediate radial annular wall <NUM>. The inner cylindrical body <NUM> comprises a first externally threaded portion <NUM> extending in the opposite direction with respect to the valve and a second portion <NUM> extending towards the valve.

The base body <NUM> is connectable to the valve via the connection means <NUM>, such as a ring nut of axis A interposed between the base body <NUM> and the valve, and comprising an inner thread. In this case, the second portion <NUM> of the inner cylindrical body <NUM> has a terminal outer prominence cooperating with the ring nut <NUM> and configured to couple in a snap-on manner therewith. Alternatively, the connection means <NUM> can be, for example, a quick coupling or a bayonet coupling.

The knob <NUM> is substantially cup-shaped extending along the axis A, and comprises a convex base wall <NUM> and a tubular wall <NUM> with an axis A which joins the base wall <NUM>. At least one of the base wall <NUM> and the tubular wall <NUM> has slots <NUM> (for example linear or circular) to allow fluidic communication of the bulb <NUM>, inserted into the knob <NUM>, with the environment outside the knob <NUM>. In the illustrated example, the knob <NUM> has three groups of slots <NUM> angularly equispaced, wherein each slot <NUM> extends radially in proximity of a circumferential edge of the base wall <NUM> and continues axially along a portion of the tubular wall <NUM> adjoining the base wall <NUM>.

The base body <NUM> and the knob <NUM> (<FIG>) have substantially equal outer diameters. In order to couple together, the tubular wall <NUM> of the knob <NUM> has, on the opposite side with respect to the base wall <NUM>, a terminal portion <NUM> with a smaller outer diameter having an outer circumferential rib <NUM> configured to engage with a respective inner circumferential groove <NUM> of the cylindrical wall <NUM> of the base body <NUM>. Therefore, the knob <NUM> is rotatable with respect to the base body <NUM>, but axially constrained thereto.

The tubular wall <NUM> of the knob <NUM> (<FIG>) is provided internally with a main axial rib <NUM> extending up to a free end of the terminal portion <NUM>. The tubular wall <NUM> of the knob <NUM> optionally has one or more inner secondary axial ribs <NUM>, of smaller length with respect to the main axial rib <NUM>, which do not extend up to the free end of the terminal portion <NUM>. In the illustrated example, the tubular wall <NUM> of the knob <NUM> has three secondary axial ribs <NUM> having radially a smaller angular width with respect to the main axial rib <NUM>, and the four ribs are angularly equispaced.

The bulb <NUM> is substantially a cylinder of axis A internally comprising a thermosensitive medium, such as (in increasing order of response speed) thermosensitive wax, thermosensitive liquid or thermosensitive gas. The thermosensitive medium expands when the temperature of the environment, with which the bulb <NUM> is in fluidic communication, increases.

The bulb <NUM> comprises a main body <NUM> and a flange <NUM>. The main body <NUM> is a cylinder of axis A, having a chamfered base <NUM>, which faces the base wall <NUM> of the knob <NUM>, and provided with the perimeter flange <NUM> at an end thereof opposite the base <NUM>. The bulb <NUM> (<FIG>) has a blind axial cavity <NUM> open on the side of the flange <NUM>.

The intermediate body <NUM> (<FIG>) is substantially a hollow cylinder of axis A, radially interposed between the terminal portion <NUM> of the knob <NUM> and the first portion <NUM> of the inner cylindrical body <NUM> of the base body <NUM>. The intermediate body <NUM> comprises a tubular element <NUM> and a fastening portion <NUM>.

The tubular element <NUM> (<FIG>) is internally threaded and screws onto the first portion <NUM> of the inner cylindrical body <NUM> of the base body <NUM>. The annular wall <NUM> of the base body <NUM> defines an axial stop for the tubular element <NUM>.

The fastening portion <NUM> comprises an annular flange <NUM> extending externally from an axial end of the tubular element <NUM> opposite the annular wall <NUM> of the base body <NUM>.

The fastening portion <NUM> further comprises a U-shaped appendage <NUM> axially extending from the flange <NUM>.

The appendage <NUM> laterally delimits a cavity <NUM> open in radial direction and has an inner prominence <NUM> defining a minimum width of the cavity <NUM> substantially equal to the diameter of the main body <NUM> of the bulb <NUM>.

The inner prominence <NUM> is axially spaced with respect to a head surface of the flange <NUM> so as to define therewith a seat <NUM> configured to accommodate the flange <NUM> of the bulb <NUM>. The inner prominence <NUM> is internally delimited by two flat surfaces <NUM> facing each other and by a semi-cylindrical surface <NUM> joining them. The flat surfaces <NUM> have respective teeth <NUM> having a substantially cusp-shaped cross-section and facing each other.

The fastening portion <NUM> of the intermediate body <NUM> (<FIG>) has externally a main axial groove <NUM> having a shape complementary to the main axial rib <NUM> of the tubular wall <NUM> of the knob <NUM>. The fastening portion <NUM> of the intermediate body <NUM> optionally has outer secondary axial grooves <NUM> cooperating with the secondary axial ribs <NUM> of the tubular wall <NUM> of the knob <NUM>. Therefore, the knob <NUM> and the intermediate body <NUM> are prismatically coupled, and a rotation of the knob <NUM> is rigidly transmitted to the intermediate body <NUM>.

The motion transmission means <NUM> (<FIG>) are substantially a pusher comprising a rod <NUM> and a piston <NUM> telescopically mounted with the interposition of a spring <NUM>.

The rod <NUM>, of axis A, is housed in the axial cavity <NUM> of the main body <NUM> of the bulb <NUM> and comprises an annular head <NUM> of axis A slidably housed in an axial cavity <NUM> of the piston <NUM>.

The piston <NUM> comprises a cylindrical lateral wall <NUM> of axis A, delimiting the axial cavity <NUM>, slidably housed in the inner cylindrical body <NUM> of the base body <NUM>.

The piston <NUM> further comprises an axial stem <NUM> provided, at an axial end thereof facing the valve, with a head <NUM> connected to the lateral wall <NUM> via spokes <NUM> at an axial end thereof facing the valve. The stem <NUM> has a smaller diameter with respect to an inner diameter of the rod <NUM> and is configured to be inserted with radial clearance into its cavity. The lateral wall <NUM> is sized to slidably house the head <NUM> of the rod <NUM>. In particular, the head <NUM> is mounted in the lateral wall <NUM> forcing it through an inner prominence thereof disposed at an end <NUM> opposite the spokes <NUM>. For this purpose, the end <NUM> is elastically expandable via a plurality of axial slots <NUM> angularly equispaced.

The spring <NUM> is radially interposed between the rod <NUM> and the stem <NUM> and is axially pre-compressed between an end shoulder of the rod <NUM>, opposite the head <NUM> of the rod <NUM> itself, and the head <NUM> of the piston <NUM>.

The thermostatic head <NUM> further comprises an axial pin <NUM> driven into a through-hole of the annular wall <NUM> of the base body <NUM>. The pin <NUM> is sized and positioned to cooperate with the main axial rib <NUM> of the knob <NUM> but not with the secondary axial ribs <NUM>, if present. Therefore, the pin <NUM> allows a stop to the rotation of the knob <NUM>, preventing rotations greater than a round angle.

An assembly cycle of the thermostatic head <NUM> (<FIG>) comprises a step in which the bulb <NUM> is rigidly coupled to the intermediate body <NUM>.

In particular, the bulb <NUM> is radially inserted into the fastening portion <NUM> of the intermediate body <NUM>, so that the flange <NUM> of the bulb <NUM> is housed in the seat <NUM> of the fastening portion <NUM>.

The fastening portion <NUM> is able to accommodate the bulb <NUM>, and to lock it, thanks to the teeth <NUM> of the two flat surfaces <NUM>. In particular, the cusp shape of the teeth <NUM> allows them to slide on the main body <NUM> of the bulb <NUM> during its insertion, and to elastically snap at the end thereof, snap-locking the bulb <NUM> into the intermediate body <NUM>.

Subsequently, the rod <NUM> of the pusher <NUM> is passed through the cavity of the intermediate body <NUM> and inserted into the axial cavity <NUM> of the main body <NUM> of the bulb <NUM>.

Subsequently, the base body <NUM> is screwed to the intermediate body <NUM> via the respective threads, creating a helical coupling therebetween.

The connection means <NUM> and the pin <NUM> can be coupled to the base body <NUM> before or after the step described above, indifferently.

Finally, the knob <NUM> is prismatically coupled to the intermediate body <NUM> (i.e. in an axially free and rotationally fixed manner) and rotoidally to the base body <NUM> (i.e. in a rotationally free and axially fixed manner).

In particular, the knob <NUM> and the intermediate body <NUM> are moved axially towards each other, making the main axial rib <NUM> of the knob <NUM> engage with the main axial groove <NUM> of the intermediate body <NUM> and, optionally, the secondary axial ribs <NUM> engage with the secondary axial grooves <NUM> of the intermediate body <NUM>. Therefore, the prismatic coupling between the knob <NUM> and the intermediate body <NUM> is obtained. Furthermore, the circumferential rib <NUM> of the knob <NUM> engages with the circumferential groove <NUM> of the base body <NUM>, thus obtaining rotoidal coupling between the knob <NUM> and the base body <NUM>.

In use, the operator can set a pre-regulation temperature by rotating the knob <NUM>. In order to facilitate the pre-regulation, a cylindrical outer surface of the terminal portion <NUM> of the knob <NUM> can have, along a circumference thereof, marks (numbers and/or pictograms) corresponding to respective pre-regulation positions, in turn corresponding to respective desired room temperatures. In this case, the cylindrical wall <NUM> of the base body <NUM> (<FIG>) has a through-hole configured to allow the operator to read, in a sequential manner, such marks. Since the bulb <NUM> is locked in the body <NUM>, which is in turn prismatically coupled to the knob <NUM> and helically coupled to the base body <NUM>, the rotation of the knob <NUM> results in an axial movement of the bulb <NUM>, defining a starting position thereof.

When the room temperature increases, the thermosensitive medium expands, causing an axial thrust of the bulb <NUM> on the rod <NUM> of the pusher <NUM> in the direction of the base body <NUM>. Via the spring <NUM> and the piston <NUM> of the pusher <NUM>, the axial thrust of the bulb <NUM> is transmitted to the valve, which reduces the flow of hot water to the radiant element. Vice versa, when the room temperature decreases, the thermosensitive medium contracts and, in the absence of the axial thrust of the bulb <NUM>, the valve returns towards the open position, increasing the flow of hot water to the radiant element. The spring <NUM> has the purpose of maintaining the rod <NUM> in contact with the bulb <NUM> and the piston <NUM> in contact with a control element of the valve, absorbing any overtravel of the bulb <NUM> when the room temperature is above the pre-regulation temperature.

Upon examination of the characteristics of the thermostatic head <NUM>, the advantages of the present invention are clear.

In particular, the knob <NUM> is rotoidally coupled to the base body <NUM>, while the intermediate body <NUM> is rigidly coupled to the bulb <NUM>, prismatically coupled to the knob <NUM>, and helically coupled to the base body <NUM>. Therefore, the rotation of the knob <NUM> around the base body <NUM> is rigidly transmitted to the intermediate body <NUM>, which rotates with respect to the base body <NUM> and simultaneously moves in axial direction. Since the bulb <NUM> is rigidly coupled to the intermediate body <NUM>, it also rotates and moves in axial direction. In other words, the intermediate body <NUM> and the bulb <NUM> roto-translate together with the base body <NUM>, while the knob <NUM> only rotates with respect thereto. Therefore, the axial movement of the knob <NUM> is eliminated, maintaining the aesthetics and geometry of the thermostatic head <NUM>, which has constant outer dimensions.

The knob <NUM> is mounted only at the end of the assembly cycle. Therefore, it is not necessary to already have the customized knob <NUM> to start the assembly cycle, and all its steps (except for the last one) are independent from customization of the knob <NUM>, with clear constructive and logistical advantages. In particular, it is not necessary to manage a large number of different components from the start of the assembly cycle.

Furthermore, rigid coupling between the bulb <NUM> and the intermediate body <NUM> is carried out at the beginning of the assembly cycle. Therefore, they can be considered as a single component in all the subsequent steps.

Preferably, the bulb <NUM> couples to the intermediate body <NUM> via a snap-on fastening, which is particularly uncomplicated and simple to make. Furthermore, the snap-on fastening avoids the use of an external element for rigid coupling, and allows the use of commercial bulbs <NUM> without the need to modify them.

According to a variant illustrated in <FIG>, the pin <NUM>, instead of being an independent component, is in one piece with the base body <NUM> and extends cantilevered from the wall of the annular wall <NUM> of the base body <NUM>. This solution, identical from the point of view of operation, is advantageous since it reduces the number of components and simplifies the assembly cycle.

Finally, it is clear that modifications and variations can be made to the thermostatic head <NUM> without going beyond the scope of protection defined by the claims.

Claim 1:
Thermostatic head for a flow control valve in a heating system, comprising a base body (<NUM>) provided with connection means (<NUM>) to the valve, a knob (<NUM>) exposed to an external environment and rotatable with respect to the base body (<NUM>) so as to set a pre-regulation temperature, and a thermosensitive element (<NUM>) at least partially inserted into the knob (<NUM>) and in fluidic communication with the external environment, the thermosensitive element (<NUM>) being configured to exert a thrust on the valve as a function of the temperature of the external environment and the pre-regulation temperature, characterized by comprising an intermediate body (<NUM>) rigidly coupled to the thermosensitive element (<NUM>), prismatically coupled to the knob (<NUM>) and helically coupled to the base body (<NUM>), the knob (<NUM>) being axially fixed with respect to the base body (<NUM>),
characterised in that
the intermediate body (<NUM>) is rigidly coupled to the thermosensitive element (<NUM>) via a snap-on fastening,
the intermediate body (<NUM>) comprises a fastening portion (<NUM>) configured to at least partially accommodate and lock the thermosensitive element (<NUM>),
the fastening portion (<NUM>) has a shape complementary to a portion of the thermosensitive element (<NUM>) in contact therewith, and comprises locking means (<NUM>) of said portion of the thermosensitive element (<NUM>) to the intermediate body (<NUM>),
the fastening portion (<NUM>) has a cavity (<NUM>) open in a radial direction with respect to an axis (A) of the thermostatic head (<NUM>) and configured for an insertion into the cavity (<NUM>) of said portion of the thermosensitive element (<NUM>) in said radial direction.