MXPA01005186A - Device for controlling the service loads of an electric household appliance, in particular a refrigerator - Google Patents

Abstract

A control unit (3) for controlling the service functions of an electric household appliance (e.g. a refrigerator) is connected in series with a positive temperature coefficient (PTC) resisting unit (4) which, when supplied with electric current, generates sufficient heat to activate thermally activated actuating means (6) for selectively connecting/disconnecting respective auxiliary switches (9) of service loads (2) corresponding to the service functions of the electric household appliance. The thermally activated actuating means (6) include a temperature-deformable element (7) (e.g. a bimetallic plate), the deformation of which is transmitted by kinematic connecting means (10) to a camshaft (8), the cams (12) of which cooperate with the auxiliary switches (9) of the service loads (2) to selectively connect/disconnect the auxiliary switches.

Description

DEVICE TO CONTROL THE SERVICE CHARGES OF AN APPLIANCE, IN PARTICULAR A REFRIGERATOR TECHNICAL FIELD The present invention relates to a device for controlling the service loads of a domestic appliance, in particular a refrigerator. PREVIOUS TECHNIQUE As is known, many appliances require systems to regulate and control one or more operating functions, which are activated or deactivated according to various operating conditions. Such is the case, for example, of a refrigerator compressor, which 'requires a' control system, which depending on the temperature variations measured inside the refrigerator, turns on or off the compressor under control, for example, the a mechanical thermostat. The compressor supply circuit usually comprises two activation branches, which are active in the starting (or "throwing") stage and the normal operating stage (operation "), respectively: in which case, a unit is used of PTC positive temperature coefficient (PTC) resistance, to regulate the flow of current through the launch branch and the mechanical thermostat to regulate the flow of current through the operating branch. The main drawback of control systems of this type is the relatively high energy consumption that this entails, which is mainly due to the presence of the continuously operating PTC unit and the difficulty in regulating the mechanical thermostat. electronic versus one mechanical and other types of relays, instead of PTC units, allow some, albeit relatively small, reduction in the consumption, but requires the use of more complex and more expensive components. DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a device for controlling the service loads of an appliance, which, while cheap and easy to produce, provides low-energy operation and long-term reliability. According to the present invention, there is provided a device for controlling the service loads of a domestic appliance, in particular a refrigerator, which consists of a control unit for regulating the service functions of the domestic appliance, and a resistance unit of coefficient of positive temperature (PTC), connected in series with that control unit; it is also characterized in that it comprises thermally activated actuating means for selectively connecting or disconnecting the respective auxiliary switches of such service loads; the PTC unit is located close to the thermally activated actuating means, and which generates, when provided with electrical current, sufficient heat to activate those thermally activated actuating means.

The PTC unit used to thermally activate the actuating means is conveniently the same unit used to directly regulate the operation of at least one power application of the domestic appliance. More specifically, such thermally activated driving means comprises at least one temperature deformable element; at least one mobile control element for controlling such auxiliary switches; and kinematic connection means between the deformable element and the mobile control element. In a preferred embodiment, the mobile control element is a cam axis, whose cams contribute to the respective auxiliary switches of such loads, to respectively connect or disconnect the auxiliary switches; at least one cam of said shaft is also used to determine the angular position of the cam shaft. The device according to the invention preferably also comprises a control circuit for regulating the PTC unit and for cyclically interrupting the supply to the PTC unit, for example, by means of an electronic switch interposed between the control unit and the PTC unit, once enough heat has been generated by means of the PTC unit, to activate the thermally activated actuating means. The device according to the invention is simple and reliable, does not require particularly complex and / or high-cost components, and as compared to known control systems, provides significant energy savings in service. The supply for the PTC unit can in fact be interrupted at the end of each cycle, to activate the service load (or loads), thus reducing the total consumption of the device. The device according to the invention is also highly flexible, controlling and regulating numerous service functions different from the appliance to which it is applied. For example, in the case of a refrigerator, in addition to the compressor, the device can also control the interior light, the fan, etc., and this using only one PTC unit, in particular, is used to control the operation of the compressor . For which purpose, in fact, the mobile control element simply needs to be provided with a number of cams to control the corresponding switches for the various loads. One or more cams can conveniently be used to determine the angular position of the mobile control element, so that the control unit is always in a condition to determine the position of the mobile control element, and therefore, the conditions of operation of the system, and may also intervene in case of failure, to activate any of the service functions. In addition, the device according to the invention allows all the heat generating components to be placed, which is best suited to the application in question. More specifically, in the case of a refrigerator, such components can be located far from the coded region, for example directly in the compressor, thus improving the overall efficiency of the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which; Figure 1 shows a block diagram of the principle of general operation of a device for controlling the service loads of a domestic appliance according to the invention; Figure 2 shows schematically, a preferred embodiment of the device, according to the invention; Figure 3 shows schematically, a circuit incorporating the device of Figure 2; Figure 4 shows a possible application of the device of Figure 2 and 3. BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figure 1, indicates in its entirety a device to control the service charges, indicated schematically by the "users "2 in Figure 1, of a household appliance, for example, a refrigerator. The control device 1 comprises a control unit 3, of any known type, for controlling the service functions of the refrigerator; a unit of resistance of positive temperature coefficient 4 (known substantially, and referred to later simply as a PTC unit) connected in series with the control unit 3; and an electrical switch 5, for example a known TRIAC switch, interposed between the control unit 3 or the PTC unit 4. According to the invention, the control device 1, also consists of thermally activated actuating means 6, for connecting and selectively disconnect service loads 2 from the refrigerator. The operation of the driving means 6 and the consequent selective activation of one or more service loads 2 are controlled by the PTC unit 4, as indicated by the control unit 3. In the preferred embodiment shown in FIG. detail in Figures 2, 3 and 4, the thermally activated actuating means 6, comprise an element that deforms the temperature 7; at least one mobile control element 8 for activating one or more auxiliary switches 9 for service loads 2; and kinematic connection means 10 between the element and the mobile control part 8. The PTC unit 4 is located near the thermally activated actuating means 6, and when supplied with electric current, generates sufficient heat to activate the actuating means 6 .. In the non-limiting example shown in Figure 2, the temperature deforming element 7 is defined by a known bimetallic plate opposite to the PTC unit 4, and selectively assumes a first shape 7a (shown by the line continues in Figure 2) under a predetermined temperature, and at least in a second shape 7b (shown schematically by the line of dashes in Figure 2) above the predetermined temperature. The amount of general heat by the PTC unit 4, when supplied with current, is sufficient to bring the temperature of the element 7 (which is located a short distance from the PTC unit 4) above the predetermined temperature and thus changes the shape of the item 7.

The mobile control element 8 is a cam shaft that rotates about a predetermined axis of rotation, and the cams 12 which contribute to the auxiliary switches 9 of the service loads 2 to connect selectively disconnect the loads. One end of the cam shaft 8 is adjusted with a wheel 13 having radial projections 14 with a predetermined space; the kinematic connection means 10 consist of a first lever 16 and a second lever 17 hinged to one another; the first lever 16 is hinged at an intermediate point 18 to a fixed support, and at the longitudinal ends opposite the second lever 17 and at one end of the deformable element 7; and the second lever 17 exerts a pulse successively in each of the radial projections 14 of the wheel 13, to rotate the cam shaft 8, by means of a predetermined angle, which corresponds substantially to the space of the radial projections 14 each once the element that deforms the temperature 7 changes from its first form 7a to the second form 7b. The kinematic connection means 10 also preferably comprise known ratchet actuation means (for example integral element with the levers 16, 17 or deformable element 7, and which is not shown for simplicity's sake) for the ratchet rotating camshaft 8. The control device 1 also comprises a control circuit 20, for regulating the PTC unit 4 and for cyclically interrupting the supply to the PTC unit 4, once the PTC unit has generated sufficient heat to activate the thermally activated actuating means 6. Preferably, the control circuit 20, comprises the switch electronic type TRIAC 5, interposed between the control unit 3 and the PTC unit 4 and the thermally activated actuating means 6, supply the electronic switch 5 with a signal, either by means of the control unit 3 (see the indicated circuit by the solid line in Figure 3) or directly (striped line in Figure 3) to interrupt the supply to the PTC unit 4. The control circuit 20 may also be conveniently used to supply the control unit 3 with a signal indicating the angular position of the cam shaft 8, for example, detected by means of one or more cams 12. In the non-limiting example shown in Figures 2 to 4, the control device 1 is connected to a known compressor 21 (but not shown in detail for simplicity's sake) by two conductive fasteners 22, 23 respectively connected to a starting branch 24 and to an operating branch 25 of a substantially known supply circuit 26 for supplying the compressor, and which is shown only schematically in Figure 3. The control device 1 also comprises a known thermal protector 30 connected to supply the compressor circuit 26 for means of a further driving fastener 31. All of the control device 1, including the thermal protector 30, can be placed in a box 32, from which the various contacts project for electrically connecting the control device 1, for example fasteners 22, 23, 31 (for connection to compressor 21), terminals 35 for connection to service loads 2, and supply contacts 36, 37, 38, for example connected respectively to the PTC unit 4, to the driving means 6, and to the outlet of the thermal protector 30. Then, the box 32 can be adjusted directly to an outer box 40 of the compressor 21 (Figure 4) in which the connections for the three conduction fasteners 22, 23, 31 are formed. Control device 1, according to the invention, functions in the following manner. When the control unit 3 detects the need to vary the operating condition of a service function 2 (or when the activation of the service function is directed directly by the user), a signal is sent to the normally open electronic switch 5, which closes to allow the flow of current to the PTC unit 4; the PTC unit 4 is heated and the increase in temperature changes the shape of the temperature deformable element 7. The temperature deformable element 7 is hinged to a first lever 16, to thereby produce a predetermined angular displacement of the first lever 16 and a corresponding displacement of the second lever 17 hinged to a first lever 16; and the second lever 17 in turn exerts an impulse in one of the radial projections 14 of the wheel 13, to rotate the wheel and the cam axis 8, by means of a predetermined angle (corresponding to the space of the radial projections 14 ). Depending on the position and configuration of the cams 12, the rotation of the cam shaft 8 closes or opens the switches 9, to activate or deactivate the corresponding service functions 2 (including, in particular, the application of energy defined by the compressor 21). ). Once the cam shaft 8 rotates the predetermined amount, which corresponds to the conversion of the element 7 when changing from the shape 7a to the shape 7b, the control unit 3 opens the electronic switch 5 to interrupt the supply to the PTC unit 4: the deformable temperature element 7 is restored to the shape 7a, and the levers 16, 17 to their original positions, suspended more to the current flow, through the PTC unit 4 to rotate the cam shaft 8 and activate the drive means 6. The changes can be made clearly to the device, as described herein, however without departing from the range of the appended claims.

Claims (11)

1. CLAIMS 1. A device for controlling the service loads of an appliance, in particular a refrigerator, consisting of a control unit for regulating the service functions of the appliance and a positive temperature coefficient (PTC) resistance unit connected in series with the control unit; it is characterized by also comprising the thermally activated actuating means for connecting or disconnecting the respective auxiliary switches of the service loads; the PTC unit is located close to the thermally activated actuating means and which generates, when supplied with electrical current, sufficient heat to activate the thermally activated actuating means.
2. 2. As the device mentioned in Claim 1, it is characterized in that the PTC unit, which is used to thermally activate the thermally activated actuating means, is the same as that which is used to directly regulate the operation of at least one application of appliance energy.
3. 3. A device as claimed in Claim 1 or 2, characterized in that said thermally activated actuating means comprises at least one temperature deformable element; at least one part of mobile control to control the auxiliary switches; and kinematic connection means between the deformable element and the mobile control part.
4. A device as noted in Claim 3, characterized in that such kinematic connection means comprise ratchet drive means for producing a ratchet movement of such a mobile control element.
5. A device as noted in Claim 3 or 4, characterized in that the temperature deformable element selectively assumes a first shape under a predetermined temperature and at least a second shape above the predetermined temperature; such a mobile control element that rotates with respect to a predetermined axis of rotation; and the kinematic connection means impart to the mobile control element, a rotation of a predetermined angle, each time the deformable element of temperature changes from the first form to at least a second form.
6. 6. A device as claimed in Claim 5, characterized in that it also comprises detecting means for detecting the angular position of the mobile control element; such detecting means for detecting the angular position of the mobile control element are connected to the control unit for supplying the control unit with a signal indicating the angular position of the mobile control element.
7. A device as noted in Claim 6, characterized in that the mobile control element is a cam shaft, whose cams contribute to the respective auxiliary switches of the service loads to selectively connect or disconnect service loads. .
8. 8. A device as noted in Claim 7, characterized in that the cam axis has at least one cam for determining the angular position of the cam shaft.
9. A device as noted in Claim 8, characterized in that the cam shaft is adjusted with a wheel having radial projections with a predetermined space; such kinematic connection means also comprise a first and second lever hinged to one another; the first plan is hinged at a respective intermediate point to a fixed support and is hinged to the respective ends of the second lever and the deformable temperature element; and the second lever exerts a pulse successively on each of the radial projections of the wheel, to impart the rotation of a predetermined angle to the axis of cams.
10. 10. A device as claimed in claim 9, characterized in that each time the deformable temperature element assumes at least a second shape, the kinematic connection means impart to the camshaft a rotation of an angle that corresponds substantially to the space of the radial projections.
11. 11. A device as claimed in claim 10, characterized in that the temperature deformable element contributes to the first lever, to produce a predetermined angular displacement of the first lever, around the respective intermediate point and a corresponding displacement of the second lever hinged to the first lever; the second lever exerts a pulse successively in each of the radial projections of the wheel, to impart the rotation of a predetermined angle to the axis of cams. A device as observed in one of the preceding Claims, characterized in that it also comprises a control circuit for regulating the PTC unit and for cyclically interrupting the supply to the PTC unit, once the PTC unit has generated sufficient heat to activate the thermally activated actuating means. A device as recited in Claim 12, characterized in that the control circuit comprises an electronic switch interposed between the control unit and the PTC unit, for selectively interrupting the supply to the PTC unit; such thermally activated actuating means provide a signal for the electronic switch, possibly by means of the control unit, to interrupt the supply to the PTC unit.