DE1765713A1 - Thermal switch - Google Patents

Description

Patent and utility model registration

Note: Sooieta per Azioni I ¹ RATELLI BORLETTI, Milan / Italy, Via. Washington 70

My reference: F 10 - Rei / Ca

Thermal switch

The priority of the Italian patent application 18172 A / 67 of July 8, 1967 is claimed.

The invention relates to a thermos holder for controlling a

connected to an electrical circuit with a screw housing for attaching the thermal switch to the to be controlled device, furthermore with one arranged in the screw housing movable contact which can be actuated by a bimetal strip, such that on the one hand at a certain Increase in the temperature of the bimetal strips in the closed position and that on the other hand with a certain decrease the temperature of the bimetal strips in the open position for the electrical circuit and with a externally actuatable adjusting member in the housing.

With conventional thermal switches, efforts are made to use the pear-shaped strip bring it as close as possible to the liquid, whose temperature is to be controlled. In many cases the y. Bimetal strips on the bottom of the housing, for example in a syXiadri-near recess in the screw part a screw housing

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arranged. This requires that the bimetal strip one Has diameter which is much smaller than that of the screw-in part of the housing. This becomes a preset very difficult, unsafe and costly within the required tight tolerances. The result is that such thermal switches are often preferred to switches, which have two separate members for adjusting the switch, one adjusting member when the temperature is increased and the other setting member is effective in lowering the temperature. Such a facility requires increased costs.

It has been found that it is not necessary with thermal switches with a screw housing the pear metal strip in to be arranged in the immediate vicinity of the medium to be controlled. This is especially true when, as in a preferred field of application of the present invention, the thermal switch for controlling the fan motor for the cooling water of a motor vehicle engine is used depending on the temperature of the cooling water.

The invention is accordingly in the case of a thermal switch as described at the beginning The type mentioned can be seen in the fact that the bimetallic strip is in a recess above the screw part of the housing is mounted, and that the bimetallic strip has a diameter which is at least equal to the diameter of the visual part of the housing is, and that also its central part with the moving contact cooperates.

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When the thermal switch according to the invention is thus the seat for the bimetal strip and thus the bimetal strip itself significantly enlarged. Consequently, a useful pre-setting of the bimetal strip before it is installed in the Housing allows. The screwing of the housing can have desired standard dimensions, for example a diameter of 2U mm.

In a preferred embodiment of the present invention, the diameter of the bimetal strip is approximately equal to the diameter of the screw part of the housing. This gives optimal conditions for a uniform as possible Heat transfer from the screw part of the housing to the bimetal strip.

Further advantages of the thermal switch according to the invention are to see in its simple, reliable and cheap construction, which makes it possible to use this thermal switch can also be used for electrical circuits with high control currents.

An elastic tongue made of insulating material is advantageously arranged over the bimetallic strip, which the bimetallic strip separated by an elastic tongue made of conductive material, which is attached to the housing insulated and in its' center carries a first contact. A second contact whose fixed position in the switch housing can be adjusted from the outside is arranged so that it acts on the first contact at the time the electrical circuit is closed.

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The upper part or the cover of the switch housing is made with advantage from an injection molding process pjastic insulating material in which during the casting process Connecting parts made of conductive material are introduced, which are each connected to one of the contacts mentioned. Each of these connecting parts has an end piece that extends over the hood-like cover protrudes and is designed as a tongue or connector to connect to a conductor of the to establish an electrical circuit.

The inner end of the first connection part is immediately at the edge of the already mentioned tongue made of conductive material, which carries the first contact, while the inner The end of the second connection part rests on the edge area of an insulated metal support part, which supports the second Contact carries. The latter is fixed in the support part so that it can be adjusted by means of an adjusting screw which is driven by a Opening in the hood-like cover of the housing inserted screwdriver can be actuated / grounded, adjustable is. After the aforementioned contact has been set, the opening is closed in a watertight manner.

The Peineeinstellung or calibration is carried out so that the second contact with respect to the first contact assumes such a position that the opposite triggering process of the Bimetal strip then takes place when the falling temperature has reached a predetermined value.

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Further details and advantages of the invention are illustrated in exemplary embodiments explained in more detail with reference to the drawing.

1 and 2 show a thermoso holder according to FIG Invention.

Fig. 2 to shows in section as a detail the insulating tongue and the movable contact. Fig. 3 shows the thermal switch according to the invention in plan view.

4 shows as a detail in plan view the elastic tongue carrying the movable contact. 5 shows an axial section through the bimetal strip

represent.
Fig. 6 shows in detail the bridge-shaped support part that carries the fixed contact.

7 and 8 show two modified embodiments in longitudinal section of the thermos holder according to the Invention.

Fig. 9 shows as a detail in a perspective view the connection part that the featen contact after Execution according to FIG. 8 carries. Figures 1Ua and 10b represent two axial sections of two modified versions of the screw part of the switch housing.

In the pig. 1, 2 and 2 bla, a metal housing designed as a screw housing is denoted by 1. The housing 1 has

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a cylindrical part 2 with a recess j>, in which a bimetallic strip 4 in the form of a curved disc is mounted so that it can move freely. The diameter 5 of the bimetal strip 4 corresponds approximately to the diameter of the screw part 6 of the screw housing 1.

It can be seen that the dimensions of the housing 1 and the Durohmesser of the bimetallic strip 4 within certain Limits can be different. Advantageously, however, the diameter of the bimetail strip 34 is approximately as large as that Diameter of the screw part 6. This ensures that the heat transfer from the screw part 6 to the bimetal strip is as uniform as possible 4 given over its entire area.

In order to obtain a unique and reproducible release of the bimetallic strip 4, it is preferably visible with a diametrical piece as aue Fig. 5, provided that · a central piece 4 * with a slight curvature which is opposite to the main curvature similar to an open truncated cone and having a diameter of about one third of the total diameter of the bimetals TREIF ens.

Within the hollow cylinder 2 and above dee bimetallic strip 4, the Bimetalletreifene is a flat annular portion 7 having a radially up to the central part 4 projecting tongue 8 of insulating material. A material known under the trade name "Mylar" , for example, which has a high breaking strength, can be used as the insulating material

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exhibits at both high and low temperatures and is an excellent insulating material.

The annular part 7 carries an annular disk 9 from a good conductor material, from which an elastic radial tongue 10 protrudes towards the center of the bimetallic strip 4. In the vicinity of the end of the tongue 10 is in the center of the annular disk 9 (see. Fig. 4) a bore 11 into which a Pin 12 from one suitable for an electrical contact Material is let in. This pin has a preferably spherical head piece. The pin 12 is on the Tongue 8 of the washer 9 with the interposition of a washer 13 and deformation of its lower end to form a spherical head piece 14.

After installation, a narrow gap remains between the spherical head piece 14 and the middle part of the bimetallic strip 4 This means that all pressure is applied when the thermal switch is in its rest position of the head piece 14 on the bimetal strip 4 avoided, whereby the trigger time could be influenced.

Above the washer 9 there is another washer 15 made of insulating material on which a bridge-shaped Support part 16 is arranged.

The three washers 7 »9 and 15 and the support part 16 are against angles! deviations and radial displacements by two Pin 17 secured, which is made in one piece with the hood-shaped

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Cover 18 of the housing 1 exist. The pins 17 engage in prefabricated holes or recesses 19 »19 'in the Ring disk 9 or in the support part 16. The pins 17 are attached in such a way that the arrangement of the ring disks 7 »9» 1b neither up nor down relative to the predetermined position can be moved or rotated below.

The position of the aforementioned four parts 7 »9 _f 15 and 16 in the recess 3 of the cylindrical part 2 of the housing 1 is maintained by the pressure of the hood-shaped cover 18 made of insulating material. The hood 18, in turn, is held by the flange 20 of the housing 1 with the interposition of a metal ring disk 21 and a rubber ring disk 22, which ensures that the interior of the housing is impermeable to water.

The hood-shaped cover 18 of the housing 1 is preferably made of plastic material to be produced by means of the injection molding process (for example "Delrin"), "with the connection parts 23 and 24 being embedded in the plastic material during the molding process. That part of the connections 23» 24 which extends through the Hood 18 extends outwards, serves as a connecting tongue for making the connections with the electrical circuit.

Due to the thermal effect of the shrinkage of the plastic material ("Delrin" or the like) , strong pressure is exerted on the two connection parts 23, 24. The connection parts 231-24 are, as in Pig. 9 , with matching slots

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provided, increasing the water tightness along its surface is increased.

The inner part of the connector 24 prints in the middle of his End 25 against an outer ßandbereich of the support part 16, this ensures a permanent electrical connection iat. The inner part of the connecting part 23, however, presses by means of its end 26 against a fiand zone 27 on the surface of the metal ring disk 9 · This creates a permanent electrical contact with the ring disk 9 and thus with the movable contact 12 made.

As mentioned, the contact 12 is in its rest position against all the other metal parts of the assembly with the exception of the Connection part 2.5 isolated.

The support part 16 has, like au3 Pig. 6, a bridge-shaped middle part with a threaded hole 28 can be seen. The threaded bore 28 coincides with the axis of the thermal switch. The threaded bore 28 is widened by a longitudinal slot 29. As a result, the bore 28 can be widened or compressed, according to the elasticity of the two parts separated by the slot. In this way, a certain pressure is exerted on the threaded bolt of the screw 50 and thus prevents this information from being unintentionally looted by vibrations. The screw "30 carries int thus electrically connected to the Anschiußteii 24 via the support member 16 at its lower sin electrical contact 31. This contact 31, while being isolated from the remaining metal parts of the switch."

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The fixed contact 31 is coaxial with the movable contact arranged, but in the rest position, as err from the drawing visibly separated from it by a gap. ,

In the insulating hood 18, a bore 32 is provided which by means of a suitable tool, for example a screwdriver, a wrench or the like. the access to steepen the screw 30 allows. With that, the

Adjustment of the device for setting the rearward release process of the pear-shaped tube 4, i.e. the release process at a predetermined value of the temperature drop can be adjusted in a known manner. When screwing in the Screw 30 brings the contact 31 closer to the contact 12. This will make the bimetal strip when it is on a Temperature rise is triggered, locked earlier. The consequence is that the release of the bimetal strip takes place at a higher temperature. The opposite is the case Case when the distance between the two contacts 12 and 31 is increased.

As already mentioned, no other settings need to be made because the triggering takes place when the temperature rises to the predetermined value. This value is determined solely by the formation of the Bimetallstreif ene 4, without any other influences. This yields a switch in a simple and schntlle way of Aehr is calibrated precisely to the two triggering temperatures dea Bimetallstrelf ene.

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After adjustment by means of the screw 30, the threaded hole 32 is closed by means of a screw 33 with a conical head piece, which is pressed against a countersunk file 52 of the hole.

A higher degree of security and a higher level of impermeability to moisture can be achieved by covering the screw head with a suitable sealing material can be achieved.

The thermal switch works as follows:

As soon as the screwing '6 of the housing 1 with water or another If the liquid is brought into contact, the arm of the liquid is applied to the screwing and from this to the Transfer bimetal strip 4. As soon as the predetermined temperature value is reached, the bimetal strip is triggered, pressing the contact 12 against the contact 31. The electrical circuit to the two connecting parts 23 and 24 leads, is through the end piece 24, the support part 16, the contact 31 »the contact 12, the washer 9 and the ^ End piece 26 closed.

If the temperature falls, the bimetal strip loosens at the predetermined In the opposite direction to the original direction. This detaches the contact 12 from the contact 31 »whereby the electrical circuit is opened.

The bimetal strip is always at the temperature of the element with which the thermal switch is in contact,

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according to the heat transfer of the metal mass of the screw, partly 6, which, as mentioned, are always in direct contact with the ·; named element. It follows that the temperature of the The screwing part is always gradual but not erratic changes, so that the mass 6 is practically not subjected to any substantial tempera turgef all. This means that the bimetal strip is practically always at the same temperature as that element to be controlled is located.

In Fig. 7 a modified embodiment of the thermal switch according to the invention is shown. In this embodiment, the support part 16 is omitted. Its function is taken over by the connection part 24% of which the inner end a, n at point 35 is bent at right angles. The horizontal part 34 of the connection part 24 ^f is provided with a threaded hole 28 ^f , into which a screw 30, which carries the contact 31, is screwed. The other parts are the same as in the embodiment already described.

Another exemplary embodiment is shown in Fig. 8 * In this arrangement, the support part 16, which is replaced by the connection part 24 ″, is also absent. This connection part is also bent at right angles at 35 ', the bent Part 36 has the shape of a plane spiral, such as in particular can be seen from FIG. 9.

The central part of the spiral 36 can be slightly elastic Deflections are subjected without it being permanently deformed. At the end of the spiral 36 a contact 31 'is attached,

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against the lower end of which the movable contact 12 is pressed when the bimetallic hoop 4 is triggered. The Binteil- ~; screw t> l presses against the top of contact 31 '»This screw is inserted into the - threaded hole ^; i52 'screwed in ^ - "- ■ - · which is placed directly in the insulating hood: t8' ^ Dle ■ Position of: Contact 31 'is put down by means of cd er aSehraube ' 6Ί ^Λ f it i After this · setting we ä ^: the screw 5f löitiieis -one ^ * - suitable ■ paints's bleak-he sealed cement, so that · ¹ ^ ^ it waterproof eäMör- ^r hand and on the other hand - gie ^ s one is secured from shock.

ι f ■.?

The remaining parts by -des il hermoschaa: ters; entsprecheri dehjenagen "in" the Mg T and 2 därges'töllten execution ^ ^{foirm.-: -;?.} ^ ⁵ -

already mentioned in detail, - is "the pear taXlstreif en -4 '^; with each of the described exemplary embodiments constantly kept at the' temperature of the element, - with which the switch is carbonized, corresponding to the heat transfer from the metal mass of the screw 6, which is always in ^{direktem'Kontäkt.} communicates with the said element, since the temperature changes of the always gradually and not abruptly to be controlled member so ist'auch the mass 6 subjected to any substantial ^ ^ temperature changes, so that one can assume that the bimetal strip 4 is practically always at the same temperature as the element to be controlled.

Under certain conditions, however, it may be advisable to modify the Sohraubteil 6 somewhat, as for example in the J ¹ Ig. 1üa and 1Ob is shown. As shown in FIG

Visible is in the screw part "6 a cylindrical Aus - ■ Take j> 8 introduced in such a way that under the bimetal strip 4 only a wall 39 of small thickness remains. A number radial holes 40 is attached to the end of the screw part 6 to prevent the formation of Luftsta.ues. In one more as can be seen from Pig10b, the recess 38 'also has the shape of a truncated cone without have radial bores.

In both cases the liquid to be controlled is separated from the bimetal strip by a metal wall, the thickness of which is kept to a minimum.

The other structural parts described above can can also be modified in the event that the electrical circuit is connected to the ground of the device to be controlled is. In this case, the connection parts 23 and 24 and the annular insulating part 7 made of conductive material are omitted existing ring disk 9 ~ will be in the middle of the hood-shaped Cover 18 pressed directly against housing 1. The circuit is closed by this earth contact. At a Such an arrangement pushes the bimetal strip 4 directly against contact 12. Only contact 31 is insulated arranged and the contact 12 presses unchanged against the contact 31 at the moment in which the circuit is closed is.

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It should also be noted that structural details of the illustrated and described Ausführungsbei-. can modify games without leaving the inventive concept,

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Claims (1)

Claims 1. Thermal switch for controlling an electrical circuit closed device with a screw housing for The thermos is attached to the device to be controlled, furthermore with a movable contact which is arranged in the screw housing and can be actuated by a bimetallic strip, such as that on the one hand at a certain increase in the temperature of the bimetal strip in the closed position and that on the other hand at a certain lowering of the temperature of the bimetallic strip in the open position for the electrical Skipping circuit, as well as with an externally operable adjusting member in the housing, characterized in that the Bimetal strip (4) is mounted in a recess (3) above the screw part (6) of the housing (1), "and that the Bimetal strip (4) has a diameter that is at least equal to the diameter of the screw part (6) of the housing (1) is, and that its central part (4 *) with the movable contact (12) together animenkt. 2. Thermal switch according to claim 1, characterized in that the diameter of the bimetal strip (4) is approximately equal to the diameter of the screw part (6) of the housing (1). - 16 109837/0474 3. Thermal switch according to claim 1, characterized in that the central part (4 ¹ ) of the bimetallic strip (4) by means of a radially projecting elastic tongue (8) of a ring part (7) arranged above the bimetal strip (4) made of insulating material with the movable contact ( 12) interacts. 4. Thermal switch according to claim 1, characterized in that the movable one. Contact (12) at the free end of an elastic Tongue (1ü), which extends from an edge part of an annular disc (9) extends against the middle part, is held, 5. Thermal switch according to claim 4, characterized in that the elastic tongue (10) and the washer "(9) from one Piece. 6. Thermal switch according to claim 1 and 4, characterized in that a connection part (23) in a hood-shaped cover (18) for the G-ehäuseausnahm (3) is introduced, in which the bimetallic strip (4) is mounted and that the bimetallic strip (4) under pressure a, n of the annular disk (9) carrying the movable contact (12) in such a way that there is a permanent elastic connection between the movable contact (12) and the connection part (23) ; 7 »thermal switch according to claim 6, characterized in that a protruding part of the housing cover (18) Connector (23) as a terminal for a conductor of the electrical circuit in which the thermal switch is located, is trained. 8. Thermal switch according to claim 3> characterized in that the movable contact (-2), protruding washer (9) by means of 'of an annular part (7J made of insulating material from a Metal part of the housing (1) is arranged insulated, wherein from the annular part (7) a radially inwardly projecting, the part forming the insulating tongue (8) is mounted between the movable contact (12) and the bimetallic strip (4). 9 »thermal switch according to claim 1, characterized in that the movable contact (12) the electrical circuit when pressing the bimetallic strip (4) against a second fixed Contact (31) closes, the position of which can be adjusted from the outside. 10. Thermal switch according to claim 9 »characterized in that the fixed contact (31) is held at the end of a screw (30) fastened in a support part (16), and that the support part (16) is arranged insulated in the housing (1). 11. Thermal switch according to claim 9 and 10, characterized in that a second connection part (24) is introduced into the hood-shaped cover (18) for the housing recess (3) in which the bimetal strip (4) is mounted, and that the lower end (25) of the connection part (24) under pressure on an edge part of a support part (16) carrying the fixed contact (31) is applied in such a way that a permanent electrical connection between the fixed contact (31) and the connecting part (24) given is. 12. Thermal switch according to claim 11, characterized in that a from the housing cover (18) protruding part of the connecting part (24) as a terminal for a conductor of the electrical circuit in which the thermal switch is located, is trained. 13. Thermal switch according to claim 11, characterized in that the edge part of the support part carrying the fixed contact (> 1) (16) from the annular disc carrying the movable contact (12) (9) by means of an annular disk (15) made of insulating material is separated. 14. Thermal switch according to claim 3 and 13? characterized, that the annular part (7) between the bimetal strip (4) and the movable contact (12) that the movable Contact bearing washer (9) that the other washer (15) a.us insulating material and that the edge zone of the support part (16) are arranged one above the other, and that their exact angular accuracy mutual position by means of two pins (17) ^ set Is that of the hood-shaped cover (18), which presses the parts mentioned, go out. - 19 109837/0474 15 · Thermal switch according to claim 9 and 11, characterized in that that the adjustable fixed contact (31) at the end of a screw (-30). is attached, which is in a screw thread a, n a inwardly extending part (34) of the second connection part (24 ') can be screwed in, and that the inwardly extending Part (34) of the connecting part (24 ') is angled by 90 ° with respect to the fixed contact (31). 16. Thermal switch according to claim 10 and 15 »characterized in that that the fixed contact (31) carrying screw (30) through an opening in the hood-shaped cover (18) of the housing (1) can be actuated through and that this opening can be closed by means of a screw head. 1.7 Thermal switch according to Claim 9 and 11, characterized in that that the adjustable fixed contact (31 ') on an inwardly extending part of the second connection part (24 ") is attached, and that the connection part (24 ") is angled relative to the fixed contact (31 ') by 90 °, the angled Part has the shape of a flat, elastically deformable spiral. 18. Thermal switch according to claim 17 »characterized in that the fixed contact (31 ') presses elastically against the end of a screw (37) which sits in a threaded hole in the hood-shaped cover (.18) of the housing (1) and that the Position of the fixed contact (31 ') is adjustable by means of the screw (37). T 0 9 8 3.7 / _0 4 7 4 iy. Thermos holder according to claim 1, characterized in that the lower part of the screw part (6) has a recess (38) whose axis coincides with that of the screw part (6), and that the a, n its bottom open recess (38) from the den Bimetallic strip (4) containing chamber is separated by means of a wall with the smallest possible thickness. 20. Thermal switch according to claim 19, characterized in that the recess (38 ') in the screw part (6) has the shape of a truncated cone has the expanded base of which is open. 21. Thermal switch according to claim 1.9, characterized in that the recess (38) in the screw part (6) is cylindrical, and that radial openings (40) at the end of the screw part (6) a Connect with the atmosphere. - 21 - 109837/0474