Sartor, Adriana (Via Ristori 8, Milano, I-20129, IT)
* * * * DESCRIPTION 5 The present invention concerns a bimetallic thermostat with exchange contact with punted circuit interposed between a sensitive thermostatic element and an exchange ielay Bimetallic thermostats are known comprising an external covering which supports an internal device made up of a base piovided with packing which suppoits contact feet which allow the connection with external devices, an exchange relay connected with the base by means of electric wiies and a sensitive thermostatic element connected in turn with said ielay by means of contact feet The space present between the external coveting and the internal device is generally occupied by insulating resin in order to prevent the feet of the thermostat from touching the projecting wires of the relay What follows is that the manufacture of a thermostat as described above is rather complex and expensive In addition in the case of breakdown the repair turns out to be difficult if not impossible; the entire thermostat must often be replaced An object of the present invention is to provide a thermostat which remains internally simple but which is utilisable without having "to drown" the internal part into an insulating material Accoiding to the invention such object is attained with a bimetallic thermostat with exchange contact comprising an external support covering and an internal device made up of a pierced base provided with a packing and with electric contacts with the outside, of a relay electrically connected with said base and of a sensitive thermostatic element electrically connected with said ielay, characterized in that it comprises in addition a printed circuit interposed between the sensing element and the ielay, The printed circuit has an easy make, it is interchangeable and it does not involve the use of filling insulating material in the space comprised between the external covering and the internal device At the same time it prevents the direct contact between feet of the sensing element and the electric whes of connection of the relay The characteristics and the advantages of the present invention will become evident from the following detailed description an embodiment thereof which is illustrated as a non limiting example in the enclosed drawings in which; Figure 1 shows an axonometry view of the thermostat according to the present invention; Figure 2 shows a view in axial section of the thermostat; Figuie 3 shows a sectional view according to the line III-ΪII of Figure 2; Figuie 4 shows a bottom plan view of the thermostat; Figure 5 shows a top plan view of the thermostat; Figuie 6 shows a bottom plan view of the plate; Figure 7 shows the electric layout of the thermostat according to the invention A bimetallic thermostat comprises an external covering 1 with male thread 11, which supports an internal device 2 made up of a pierced base 3, provided with a packing 4, which supports electric connection external feet 5, 15, 25, 35, which are connected with a printed circuit insulating plate 7 by means of electric wires 6 A ielay 8 is fastened to said plate 7, with which a sensitive thermostatic element 9 is connected by means of feet 10 The plate 7 has on one of its faces two slots 12, in order to house the feet 10, and holes 13 for the ends of the wires 6 In addition it has holes 14 for the fastening of the ielay 8 and printed circuit routes 16 The plate 7 allows to prevent interferences between the feet 10 of the sensing element 9 and the wires adjacent the relay 8, situation which could create the short circuit of the ielay oi in any case the non correct operation of the same ielay 8 with consequent wrong output signals through the external feet 5 This solution allows an easy assemblage of the theimostat which is as a iesult without any filling insulating material In addition any possible technical problem can be solved owing to the easy disassembly: substitution of the ielay 8 oi sensing element 9, contacts which fail, etc. Theie is theiefoie a certain inteichangeability of the elements The ieduction of manufacturing times togethei with the simplicity of the device justifies a substantial ieduction in costs In fϊguie 7 the electric layout of the above described thermostat is illustrated, where 5 and 15 are the feeding feet, 25 is the output foot in the opeiation with normally closed contact and 35 is the output foot in the operation with normally open contact, where the two feet 25 and 35 are selected alternatively as a function of the excitation state or non-excitation state of the relay 8, in turn function of the sensing element 9,
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