EP2195717A2

EP2195717A2 - A thermostat

Info

Publication number: EP2195717A2
Application number: EP08784428A
Authority: EP
Inventors: Bjarne Frederiksen; Anders Ostergaard Clausen
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2007-08-28
Filing date: 2008-08-26
Publication date: 2010-06-16
Also published as: WO2009026922A3; WO2009026922A2; CN101939715A; RU2010110674A

Abstract

The invention provides a thermostat (1) for controlling a room temperature by- operating a valve of a radiator. To prevent unintended adjustment of the temperature, the thermostat comprises a locking structure which may prevent changing of a temperature set-value. The thermostat comprises a handle (5) fo setting the set-value by rotation of the handle relative to the base (4), and to improve the thermostat and to provide a more simple operation of the thermostat, the handle is also moveable relative to the base for locking and unlocking the locking structure.

Description

A THERMOSTAT

TECHNICAL FIELD

The present invention relates to thermostats e.g. for radiators and convectors, and more particularly to a thermostat with a locking structure which prevents changing of a selected set-value for a desired temperature.

BACKGROUND OF THE INVENTION

Thermostats of the above mentioned kind can be applied for controlling thermal conditions in an environment both in combination with refrigeration and air conditioning systems where the thermal installation is adapted to cool down the environment and in combination with heating systems where the thermal installation is adapted to heat up the environment. In the following, it is considered that the thermostat in question controls a valve and thus a thermal condition of an environment, and it may be applied both in combination with a heating and a refrigerating system.

The set-value indicates a desired temperature, and the thermo sensitive element adjusts the position of a shoulder based on a sensed temperature. The associated valve typically has a spindle which is slidingly received in a valve house. The spindle controls the position of a valve member relative to a valve seat and thus a flow through the valve. The shoulder abuts the spindle, and the spindle therefore moves when the shoulder is moved towards the spindle, and the flow through the valve is therefore changed depending on the movement of the shoulder. Safety elements for thermostats, e.g. for radiators, convectors, and/or floor heating systems, have been produced in order to secure such thermostats against unintended changing of the temperature set-value.

Common thermostats comprise a rotary knob which serves for adjustment of the desired temperature value, and common safety elements have been developed which prevent access to the knob.

One example of such a safety element is disclosed in GB 1 564 047. The disclosed thermostatic regulating valve comprises a safety device surrounding a skirt of the rotary adjustment knob and a connecting unit and can be clamped thereto to prevent rotation of the knob relative to the connecting unit, thereby preventing rotation of the knob in order to conserve energy and in order to prevent theft of the thermostat.

EP 0 702 764 B1 discloses a safety device in which it is possible to lock the rotary knob within a selectable range of values.

DESCRIPTION OF THE INVENTION

It is an object of the invention to improve the existing thermostats and to reduce the risk of unintended adjustment of thermostats in a simpler manner. Accordingly, the invention provides a thermostat with a locking structure which is controllable by movement of the handle relative to the base to shift between a locked configuration in which change of a selected temperature set-value is disabled and an unlocked configuration in which change of a selected temperature set-value is enabled. Since the locking structure is controllable by movement of the handle which is also used for selecting the set-value, the thermostat becomes very simple to manufacture and to use, and the design may be much simpler and more appealing than that of thermostats with a locking device which covers the thermostat and thus changes its appearance. In addition, any impact an externally attached locking device may have on the ability of the thermostat to correctly sense a room temperature, may be avoided.

The base may form a flange or cavity with a structure which facilitates connection of the thermostat to a matching structure of a valve. The base therefore serves to hold the thermostat in a fixed, or at least a releasably fixed, connection with the valve. The base may even form part of the valve so that the thermostat forms part of the valve.

The handle and the base may form a shell structure which encapsulates the thermo sensitive element, a structure by which the handle sets the set- value, the locking structure, and/or other parts of the thermostat.

The handle may be allowed to rotate around an axis, e.g. an axis which extends through the shoulder. In particular, the rotation axis may be parallel or coaxial with an axis along which the spindle of the valve slides towards and away from the thermostat during movement of the shoulder.

The thermo sensitive element could be of the kind known from existing thermostats, e.g. where a substance changes volume based on its temperature, and where a rod is pushed towards the associated valve by the increasing volume of the substance.

In the following text, "forward" indicates a movement towards the base and valve, and "rearward" indicates a movement away from the base and valve. The locking structure may be controllable by a translatory forward or rearward movement of the handle, e.g. along an axis around which the handle is rotational relative to the base.

The locking structure may e.g. provide selective disabling and enabling of rotation of the handle relative to the base. In one embodiment, the rotation can be disabled and enabled by providing a first surface pattern on the base and a second surface pattern on the handle so that the surface patterns can engage each other and prevent rotation of the handle relative to the base in one axial position of the handle relative to the base. The first and second surface patterns could be provided so that they engage each other during the mentioned forward or rearward sliding of the handle relative to the base. The surface patterns may therefore comprise cooperating depressions and protrusions, knops, grooves and tongue etc, and primarily of the kind extending along a line in the direction in which the handle slides relative to the base.

The thermostat may comprise a set-value structure which cooperates with the handle to move the thermo sensitive element upon rotation of the handle. The set-value structure may comprise a third surface pattern adapted for cooperation with the second surface pattern. The third surface pattern may correspond to the first and second surface patterns, and the second and third surface patterns could be provided so the aforementioned forward or rearward sliding of the handle relative to the base is enabled without causing disengaging of the second and third surface patterns.

At least one of the mentioned surface patterns may comprise a toothed surface portion. In one embodiment, the handle comprises an internally toothed surface. In this embodiment, the base and/or the set-value structure may each have a matching toothed surface, in particular with straight teeth extending in the axial direction so that the handle can be moved in this direction while teeth engaging each other can slide against each other in the direction of movement. In an alternative embodiment, one or both of the base and set-value structure may comprise a protrusion which engages between two of the teeth of the toothed surface portion provided on the handle. The thermostat may comprise a biasing structure which biases the handle toward the position in which the locking means is in the locked configuration. Such biasing means may e.g. comprise springs such as helical springs or disk springs, or it may comprise a gas which is compressed when the handle is moved to the position in which the locking means is in the unlocked configuration.

The thermostat may further comprise a dial which is indicative of the selected temperature set-value. If the handle is slidable relative to the base, the dial may be covered by the handle or the base when the locking structure is in the locked configuration, and wherein movement of the handle relative to the base may uncover the dial.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred embodiment of the invention will now be described in further details with reference to the drawing in which:

Fig. 1 illustrates a thermostat according to the invention;

Figs. 2, 3 illustrate movement of the handle between a locked and an unlocked position;

Figs. 4, 5 illustrate enlarged cross-sectional views of the locking structure and;

Fig. 6 illustrates an exploded view of the thermostat.

Referring to Fig. 1 , the thermostat 1 according to the invention comprises a thermo sensitive element which moves a shoulder whereby it becomes adapted to adjust a flow through a valve which is attached in the forward opening 2. The thermo sensitive element and shoulder are contained in the cavity 3, but they are not shown in Fig. 1. The thermostat further comprises a valve base 4, a handle 5, and a locking structure which will be explained in further details with reference to the following figures. In elevational views, Figs. 2 and 3 illustrate that the handle 5 is slideable by a translatory movement of the handle relative to the base between a locked and an unlocked position. The thermostat comprises a set-value structure 6 which comprises an internal threading 7 adapted to move the thermo sensitive element and shoulder in the forward direction towards the valve - the forward direction is indicated by the arrow 8 and an opposite rearward direction is indicated by the arrow 9.

In Fig. 2, the locking means is in a locked configuration and the base 4 and handle 5 form a closed shell with an opening 2 in which the valve is receivable. The position of the handle 5 shown in Fig. 2, i.e. the foremost position of the handle 5 relative to the base 4, will be referred to as the locked position.

In Fig. 3, the translatory movement of the handle 5 along an axis, symbolized by the dotted line 10, has changed the locking means to the unlocked configuration in which the handle 5 is rotational relative to the base 4 around the axis 10. The rearmost position of the handle 5 relative to the base 4 will be referred to as the unlocked position of the handle.

Fig. 4 illustrates an enlarged cross-sectional view of the locking structure. The locking structure comprises a first surface pattern 11 provided on the base 4 and arranged to engage a second surface pattern 12 provided on the handle 5, when the handle 5 is in the foremost position. In this embodiment, the first surface pattern is constituted by an externally toothed surface formed on an outward inner flange 13 of the base 4 and the second surface pattern is constituted by an internally toothed surface provided on the flange 14 of the handle 5. The surface patterns are better seen in Fig. 6 showing an exploded view of the thermostat. In Fig. 4, the first and second surface patterns engage each other and thereby disable rotation of the handle relative to the base and thus disable changing of the set-value.

Fig. 5 illustrates the view of the thermostat corresponding to Fig. 4, but with the handle in the locked position.

The set-value structure 6 is best seen in Fig. 6. The third surface pattern 15 is constituted by a toothed surface 15 on an outer surface. The third surface pattern 15 is also engaged by the second surface pattern 12, and when the handle 5 is in the unlocked position, rotation of the handle 5 can be transferred to the set-value structure 6 which, via the internal threading 7 transfers the rotation to a translatory movement of the thermo sensitive element and shoulder in a direction towards or away from the valve.

Claims

1. A thermostat (1 ) which is attachable to a valve, the thermostat (1 ) comprising a thermo sensitive element adapted to adjust a flow through the valve depending on a sensed temperature and a temperature set- value, the thermostat further comprising a valve base (4), a handle (5), and a locking structure (11 ,12), where the handle (5) is movable by rotation relative to the base (4) between angular positions whereby different temperature set-values are selected, and the locking structure (11 , 12) is controllable by movement of the handle (5) relative to the base (4) to shift between a locked configuration in which change of a selected temperature set-value is disabled and an unlocked configuration in which change of a selected temperature set-value is enabled.

2. A thermostat according to claim 1 , wherein the locking structure (11 , 12) is controllable by a translatory movement of the handle (5).

3. A thermostat according to claim 2, wherein the translatory movement of the handle (5) is along an axis around which the handle (5) is rotational relative to the base (4).

4. A thermostat according to any of the preceding claims, wherein the locking structure (11 , 12) is adapted to disable and enable change of the selected temperature set-value by disabling and enabling rotation of the handle (5) relative to the base (4).

5. A thermostat according to any of the preceding claims, wherein the locking structure comprises a first surface pattern (11 ) provided on the base (4) and arranged to engage a second surface pattern (12) provided on the handle (5).

6. A thermostat according to any of the preceding claims, comprising a set-value structure (6) cooperating with the handle (5) to move the thermo sensitive element upon rotation of the handle (5), the set-value structure (6) comprising a third surface pattern (15) adapted for cooperation with the second surface pattern (12).

7. A thermostat according to any of claims 5-6, wherein at least one of the surface patterns (11 , 12, 15) comprises a toothed surface.

8. A thermostat according to any of the preceding claims, comprising a biasing structure for biasing the locking structure (11 , 12) towards the locked configuration.

9. A thermostat according to any of the preceding claims, comprising a dial indicative of the selected temperature set-value, wherein the dial is covered by the handle (5) or the base (4) when the locking structure (11 , 12) is in the locked configuration, and wherein movement of the handle (5) relative to the base (4) to shift the locking structure from the locked to the unlocked configuration uncovers the dial.

10. A thermostat according to any of the preceding claims, wherein the base (4) and the handle (5) together form a closed shell structure which encapsulates the locking structure (11 , 12).

11. A thermostat according to claim 10, wherein the locking structure (11 , 12) is located between the closed shell structure and the thermo sensitive element.