DESCRIPTION

Background of the invention

The present invention relates to a lamp holder with an electromechanical integrated thermostat for refrigerators.

Domestic refrigerators are usually equipped with an electromechanical thermostat which detects the temperature inside the refrigerator and controls switching on and off of the refrigerating system depending on whether the temperature detected is higher than or less than a set temperature. Usually the electromechanical thermostat is also equipped with a main switch for switching off the refrigerator. Domestic refrigerators also comprise a lamp holder unit which has a switch controlling switching on of the lamp when the door is opened. The lamp holder unit is usually mounted in the immediate vicinity of the electromechanical thermostat.

Solutions are known where the lamp holder unit is provided with electrical connectors which engage with corresponding connectors provided on the outer casing of the thermostat. In the known solutions, the lamp holder unit and the thermostat are two separate and autonomous components which are fixed and electrically connected together during assembly on the refrigerator.

Object and summary of the invention

The object of the present invention is to provide an integrated thermostat/lamp holder unit which incorporates in a single component the functions of the conventional electromechanical thermostat and the lamp holder unit.

In particular, the object of the present invention is to provide an integrated thermostat/lamp holder unit which is formed by a small number of components and which can be assembled in a simple and rapid manner.

According to the present invention these objects are achieved by an integrated thermostat/lamp holder unit having the characteristic features of claim 1.

The claims form an integral part of the teaching provided here in relation to the invention.

Brief description of the drawings The invention will now be described in detail with reference to the accompanying drawings which are provided purely by way of a non-limiting example, where:

- Figure 1 is a perspective view of an integrated thermostat/lamp holder unit according to the present invention;

- Figure 2 is a partially exploded perspective view of the thermostat/lamp holder unit according to Figure 1 ;

- Figure 3 is a perspective view of the lamp holder body in the direction of the arrow III of Figure 2;

- Figures 4 to 5 are cross sections along the line IV-IV of Figure 1 in two operating positions; and

- Figure 6 is a schematic plan view showing the electric circuit of the thermostat/lamp holder unit according to the invention.

Description of embodiments of the invention

In the following description, various specific details aimed at providing a fuller understanding of the invention are explained. The embodiments may be implemented using one or more of the specific details or using other methods, components, materials, etc. In other cases, known structures, materials or operations are not shown or described in detail so that the various aspects of the invention may be understood more clearly. The reference to "an embodiment" in the context of this description indicates that a particular configuration, structure or characteristic feature described is included in at least one embodiment. Therefore, phrases such as "in an embodiment", which may occur at various points in this description, do not necessarily refer to the same embodiment. Moreover, particular forms, structures or characteristic features may be combined in any suitable manner in one or more embodiments.

With reference to Figures 1 and 2, 10 denotes an integrated thermostat/lamp holder unit for refrigerators according to the present invention. The thermostat/lamp holder unit 10 comprises a thermostat support 12 and a lamp holder body 14 which are fixed together so as to form an integrated autonomous unit.

With reference in particular to Figure 2, the thermostat support 12 is preferably made of folded sheet metal and has substantially the form of a parallelepiped with two open adjacent sides. The thermostat support 12 comprises two lateral walls 16 which are parallel to each other, a bottom wall 18 which is perpendicular to the side walls 16 and a front wall 20 which is perpendicular to the side walls 16 and to the bottom wall 18. The thermostat support 12 is open along the sides of the parallelepiped opposite to the bottom wall 18 and to the front wall 20.

With reference to Figures 4 and 5, the unit 10 comprises a bellows thermostatic element 22 which is mounted on the bottom wall 18 of the thermostat support 12. The bellows thermostatic element 22 is able to expand and contract in a direction perpendicular to the bottom wall 18 following a variation in volume of a fluid contained inside it. The bellows element 22 is connected to a temperature probe 24 which extends outside the thermostat support 12 and which may consist for example of an elongated capillary tube.

With reference to Figures 2, 4 and 5, the thermostat support 12 contains a pivoting plate 26 connected pivotably to the side walls 16 of the thermostat support 12 about a transverse axis denoted by A in Figure 2. Hinging of the pivoting plate 26 with the side walls 16 may be performed by means of lateral projections of the plate 26 which engage with corresponding internal projections of the side walls 16. A first spring element 28 acts on the pivoting plate 26 so as to generate a torque about the axis A which presses the plate 26 against a front end of the bellows thermostatic element 22. In one embodiment the spring element 28 is formed by a helical spring having a first end fixed to a nut 34 with which a screw 30 engages, said screw having a head which rests on the edges of a hole formed in the front wall 20. A second end of the spring 28 is fastened to a flange 32 of the pivoting plate 26. It will be understood that the helical spring 28 exerts a resilient recall force between the front wall 20 and the flange 32 of the plate 26, generating with respect to the fulcrum A of the pivoting plate 26 a torque which tends to press the pivoting plate 26 against the bellows thermostatic element 22. The recall force of the helical spring 28, and consequently the torque acting on the pivoting plate 26, may be adjusted by rotating the screw 30. Rotation of the screw 30 allows the prestress force of the spring 28 to be increased or decreased.

Still with reference to Figures 2, 4 and 5, the pivoting plate 26 has a screw 36 which has the function of actuating a thermostat switch as will be described below.

With reference to Figures 2 and 3, the lamp holder body 14 comprises a lamp seat 38, a transverse wall 40 and a longitudinal wall 42. The lamp seat 38, the transverse wall 40 and the longitudinal wall 42 are formed as one piece. In one embodiment, the lamp holder body 14 is formed as a single piece of injection-molded plastic. With reference to Figure 2, the lamp holder body 14 is fixed to the thermostat support 12 so that the transverse wall 40 and the longitudinal wall 42 of the lamp holder body 14 close the two open sides of the thermostat support 12. In particular, the transverse wall 40 is arranged facing and parallel to the front wall 20 of the thermostat support 12 and the longitudinal wall 42 is arranged facing and parallel to the bottom wall 18 of the thermostat support 12. In one embodiment, fixing of the lamp holder body 14 to the thermostat support 12 is performed by means of lugs 44 which are provided on the edges of the side walls 16 and the front wall 20 of the thermostat support 12 and which retain the lamp holder body 14, ensuring stable fixing between the lamp holder body 14 and the thermostat support 12 (see in particular Figure 1).

With reference to Figures 1 and 2, the lamp holder body 14 has a regulating pin 46 mounted rotatably on the longitudinal wall 42 about an axis B perpendicular to the longitudinal wall 42. The regulating pin 46 has a portion which projects outside the thermostat support 12 and on which a regulating knob (not shown) is intended to be mounted.

With reference to Figure 3, the regulating pin 46 is integral with a cam 48 situated on the inner side of the longitudinal wall 42. The cam 48 cooperates with a sliding piece 50 which is movable with respect to the longitudinal wall 42 in a rectilinear direction C perpendicular to the axis of rotation B. The sliding piece 50 is guided in the direction C by contact with lateral edges 52 of the longitudinal wall 42. The cam 48 is in contact with a seat 54 of the sliding piece 50. The cam 48 and the seat 54 are shaped so that a rotation of the cam 48 about the axis B produces a displacement of the sliding piece 50 in the rectilinear direction C.

Still with reference to Figure 3, the carriage 50 has a flange 56 to which one end of a second spring element 58 is fastened. In one embodiment the second spring element 58 is a compressed helical spring which has one end fixed to a nut 60 inside which a screw 62 engages, said screw having a head which engages with the flange 56 of the sliding piece 50. The second spring element 58 has a second hook-shaped end 64.

With reference to Figures 4 and 5, the hook-shaped end 64 of the second spring element 58 is fastened to a flange 66 of the pivoting plate 26. The end 64 of the spring element 58 is fastened to the flange 66 after assembly of the lamp holder body 14 on the thermostat support 12. In order to engage the end 64 on the flange 66 a tool (not shown) may be used, said tool being inserted through a hole provided in the longitudinal wall 42 of the lamp holder body 14.

As can be seen in Figures 4 and 5, the second spring element 58 is arranged on the opposite side of the pivoting plate 26 to the first spring element 28. The second spring element 58 generates a resilient force between the sliding piece 50 and the pivoting plate 26. The resilient force produced by the second spring element 58 generates on the pivoting plate 26 a torque relative to the fulcrum A opposing the torque applied to the pivoting plate 26 by the first spring element 28. Rotation of the regulating pin 46 about the axis B produces a displacement in the direction C of the sliding piece 50. This displacement varies the resilient force applied by the second spring element 58 on the pivoting plate 26 and, consequently, the torque applied by the second spring element 58 to the pivoting plate 26. The resultant torque which acts on the pivoting plate 26 is determined by the difference in the torques produced by the first spring element 28 and by the second spring element 58. Therefore the angular position of the regulating pin 46 about the axis B allows adjustment of the overall torque with which the pivoting plate 26 is pressed against the bellows thermostatic element 22. The torque which presses the pivoting plate 26 against the bellows element 22 opposes expansion of the bellows thermostatic element 22. The angular position of the pivoting plate 26 with respect to the fulcrum A therefore depends on the temperature of the fluid inside the bellows thermostatic element 22 and the angular position of the regulating pin 46. For the same position of the regulating pin 46, the position of the pivoting plate 26 about the fulcrum A depends exclusively on the temperature of the fluid inside the bellows thermostatic element 22. Figures 4 and 5 show, respectively, the minimum and maximum expanded position of the bellows thermostatic element 22.

With reference to Figure 6, the thermostat/lamp holder unit 10 comprises an electric circuit 70 integrated in the lamp holder body 14. The electric circuit 70 comprises a main switch 72, a thermostatic switch 74, a lamp switch 76 and a connector 78. The main switch 72 and the thermostatic switch 74 comprise respective fixed contacts 80, 82 and respective movable contacts 84, 86. The lamp switch 76 comprises two fixed contacts 88, 90 which cooperate with a movable contact 92 mounted on a shaft 94 movable in the longitudinal direction C. The connector 78 comprises four terminals which are indicated by 96, 98, 100 and 102, respectively. The fixed contacts 80, 82 of the main switch 72 and the thermostatic switch 74 are connected to the terminals 98, 100, respectively, by means of conductors 104, 106. The movable contacts 84, 86 are formed by resilient conducting strips mounted on a fixed strip 108 which is fixed to the longitudinal wall 42 of the lamp holder body 14. The fixed strip 108 is connected to the terminal 102 of the connector 78 by means of a conductor 110. The fixed strip 108 is also connected to the fixed contact 88 of the lamp switch 76 by means of a conductor 112. The terminal 96 of the connector 78 is connected to a lateral contact 114 of the lamp seat 38. The fixed contact 90 of the lamp switch 76 is connected to a front contact 118 of the lamp seat 38 by means of a conductor 120. In a preferred embodiment all the conductors of the electric circuit 70 are co-molded with the plastic forming the lamp holder body 14.

The terminal 98 of the connector 78 is intended to be connected to the live wire of the power supply line and the terminal 96 is intended to be connected to the neutral wire of the power supply line. The terminals 100, 102 of the connector 78 are intended to be connected to the compressor of the refrigerating system. When the main switch 72 is open, the fixed strip 108 is disconnected electrically from the live terminal 98. In this condition the terminal 102 and the fixed contact 88 are disconnected from the live of the power supply. Consequently, the compressor of the refrigerating system is always deactivated, irrespective of the position of the thermostatic switch 74 and the lamp L is always switched off, irrespective of the position of the lamp switch 76.

When the main switch 72 is closed, the fixed strip 108 is electrically connected to the fixed contact 80 via the movable contact 84. Consequently, the fixed strip 108 is electrically connected to the live terminal 98. Therefore the terminal 102 and the fixed contact 88 are both electrically connected to the live terminal 98. In this condition the lamp L is lit if the switch 76 is closed and is switched off if the switch 76 is open; the compressor of the refrigerating system is deactivated if the thermostatic switch 74 is open and is active if the thermostatic switch 74 is closed.

With reference to Figures 4 and 5, the screw 36 of the pivoting plate 26 actuates the movable contact 86 of the thermostatic switch 74. The thermostatic switch 74 is open in the minimum expansion condition of the bellows thermostatic element 22 (Figure 4) and is closed in the maximum expansion condition of the bellows element 22 (Figure 5).

With reference to Figure 3 the main switch 72 is operated by means of a lever 122 hinged with the longitudinal wall 42 of the lamp holder body 14. The lever 122 has a first arm 124 which acts on the movable contact 84 of the main switch 72 and a second arm 126 which acts on a front ramp surface 128 of the cam 48. The front surface 128 is shaped so that the main switch 72 is open when the regulating pin 46 is in a switched-off position.

Obviously, without affecting the principle of the invention, the constructional details and the embodiments may be greatly varied with respect to that described and illustrated without thereby departing from the scope of the invention as defined in the accompanying claims.