DK2843680T3

DK2843680T3 - Temperature dependent switch

Info

Publication number: DK2843680T3
Application number: DK14179631.8T
Authority: DK
Inventors: Marcel P Hofsaess; Hans-Christian Liehr
Original assignee: Thermik Gerätebau GmbH
Priority date: 2013-08-07
Filing date: 2014-08-04
Publication date: 2017-09-04
Also published as: PL2843680T3; ES2637659T3; EP2843680A2; DE102013108504C5; EP3229255B1; EP2843680A3; EP2843680B1; EP3229255A1; DE102013108504B4; DE102013108504A1

Description

The present invention relates to a temperature-dependent switch having a first and second external terminal, a stationary contact part which is connected to the first external terminal in an electrically conductive manner, a moveable contact part which cooperates with the stationary contact part and is secured to a spring element which is connected to the second external terminal in an electrically conductive manner and presses the moveable contact part against the stationary contact part, a bimetallic element and a plunger arranged between the bimetallic element and the spring element, wherein the bimetallic element, upon the exceeding of a switching temperature, presses the plunger against the spring element, such that the moveable contact part is disengaged from the stationary contact part, and having a snap-action spring element, which presses the plunger against the spring element, at least upon exceeding of the switching temperature. A switch of this type is known from US 2013/0057381 A1. A switch known from DE 10 2011 016 896 B3 is an temperature protection switch in which, by the switching movement of a bimetallic disc, push forces are transmitted via a plunger to a current-carrying spring element which, in this case, acts as a closing spring. The closing spring carries a moveable contact part which, when the switch is closed, is pressed against a stationary contact part. The stationary contact part and the closing spring are connected respectively to a terminal sheet. The two terminal sheets are secured to an insulating body, out of which they project laterally. The temperature protection switch has a flat housing, out of which the two terminal sheets project as external terminals.

Temperature-dependent switches of this type are employed, in a known manner, for the protection of electrical devices against overheating. To this end, by means of its two external terminals, the switch is electrically connected in series with the device to be protected, and is mechanically arranged on the device such that it is thermally connected with the latter.

In the embodiment of a switch according to DE 44 28 226 C1, a housing accommodates a temperature-dependent switching mechanism comprised of a snap-action spring disc, a bimetallic snap-action disc and a moveable contact part which, when the switch is in a closed state, is in bearing contact with a stationary contact part on the interior of the upper part, which contact part is thro ugh-contacted outwardly to a first terminal on said upper part. The conductive lower part acts as the second terminal.

The operating current of the device to be protected thus flows through the two contact parts and the snap-action spring disc into the lower part.

The switch known from DE 44 28 226 C1 is provided with a heating resistor, which is electrically connected in series with the external terminals, and which serves for a current-dependent switching function. The operating current of the device to be protected thus flows continuously through said heating resistor, which can be dimensioned such that, upon exceeding of a specified operating current, it heats the bimetallic snap-action disc to a temperature exceeding its response temperature, such that the switch already opens in the case of a raised operating current, before any unacceptable heating of the device to be protected has occurred.

Below the response temperature of the bimetallic snap-action disc, the electrical circuit is closed, and the device to be protected is supplied with current via the switch. If the temperature increases beyond a permissible value, either as a result of an excessive operating current or as a result of an excessive heating of the device to be protected, the bimetallic snap-action disc is deformed such that the snap-action spring disc switches from its first stable geometrical configuration, in which it presses the moveable contact part against the stationary contact part, into its second stable geometrical configuration, in which it disengages the moveable contact part from the stationary contact part. The switch is opened, and the power supply of the device to be protected is interrupted.

The now de-energized device can cool down again. The switch, which is thermally connected to the device, thus cools accordingly, and recloses automatically. While a switching behaviour of this type can be entirely rational for the protection e.g. of a hairdryer, such a behaviour is entirely undesirable in all cases where the device to be protected, after having been switched off, is not allowed to be reconnected automatically, in order to prevent damages. This applies e.g. to electric motors which are employed as drive units.

Consequently, known temperature-dependent switches are frequently provided with a so-called self-holding resistor, which is electrically connected in parallel with the terminals, as also described in DE 44 28 226 C1. When the switch is open, the self-holding resistor is electrically arranged in series with the device to be protected, through which, as a result of the resistance value of the self-holding resistor, only a harmless residual current flows. However, this residual current is sufficient to heat up the self-holding resistor to an extent such that it radiates heat that maintains the bimetallic snap-action disc at a temperature above its switching temperature.

Further to the embodiment of the switch according to DE 44 28 226 C1, the temperature-dependent switching mechanism can comprise only a bimetallic snap-action disc, which carries the moveable contact part and thus conducts the operating current.

The switching mechanism can also comprise a bimetallic spring-tongue, as described in DE 198 16 807 A1. On its free end, this bimetallic spring-tongue carries a moveable contact part, which cooperates with a stationary counter contact. The stationary counter contact is electrically connected to the first terminal, wherein the second contact is electrically connected to the fixed end of the bimetallic spring-tongue. The bimetallic spring-tongue thus conducts the operating current of the electrical device to be protected.

If the temperature-dependent switch is required to carry exceptionally high currents, a current transfer element is frequently employed, in the form of a contact bridge or a contact disc, which is moved by a spring element and carries two contact parts which cooperate with two stationary counter contacts; c.f. for example DE 26 44 411 A1.

In this manner, the operating current of the device to be protected flows from the first counter contact via the first contact part into the contact disc, via the latter to the second contact part, and from the latter to the second counter contact. The spring element thus carries no current. It is also known to use the spring element itself as a contact bridge for the conduction of the operating current, for example a bimetallic snap-action disc or a snap-action spring disc cooperating against a bimetallic element.

Known switches must be capable of the reliable protection of motors, both at their limit of operation at maximum permissible capacity, and with a locked rotor. In order to confirm this performance capability of switches, two tests are customarily executed.

In the “heating test”, the motor is operated at maximum capacity, wherein neither the current flux in the switch nor the heat transmitted from the motor to the switch is permitted to result in the opening of the switch.

Conversely, in the “locked rotor test”, the motor is connected to the operating voltage with the rotor locked, as a result of which an operating current flowing in the motor is between three and five times greater than the customary operating current.

Of course, this high current also results in the heating of the motor, and consequently in an increase in the temperature of the switch. In order to protect the motor against overheating, an effective thermal coupling of the switch to the motor must be ensured.

In addition to effective thermal coupling, the switch must also be capable of completing the requisite number of switching cycles which, in accordance with the typical requirements described above, should be a minimum of 3,000 cycles.

In order to permit the conduction of high operating currents by the switch, without resulting in the heating of the bimetallic disc to its switching temperature, the generic document DE 10 2011 016 896 B3 proposes that the clearance between the current-carrying closing spring and the bimetallic disc is increased by means of the mechanically interposed plunger.

The bimetallic disc is moreover arranged in a recess on an outer surface of the insulating body in order to permit, firstly, the thermal decoupling thereof from the current-carrying closing spring, and secondly an effective thermal coupling of the bimetallic disc with the device to be protected.

In principle, the temperature-dependent switching mechanism employed in the known switch is configured in the form of a “thermostat switch”, which is used for the regulation of the temperature of a device which is equipped therewith, for example for the regulation of the temperature of a hotplate. Examples of thermostat switches of this type are subject to protective rights under the terms of the following: DE 31 36 312 A1, DE 196 37 706 A1, US 3,972,016 A, US 4,669,182 A, US 5,059,937 A and US 2004/0066269 A1.

The switch known from the generic document DE 10 2011 016 896 B3 thus deviates from the customary design of a temperature-dependent switch according to DE 44 28 226 C1, although it is designed as an over-temperature protection switch, rather than as a thermostat.

The switch according to DE 10 2011 016 896 B3 has in particular the disadvantage that, at relatively high operating currents, it can only withstand a limited number of switching cycles, and is thus subject to premature failure.

Tests conducted on the premises of the applicant have shown that, in a locked rotor test at 120 V AC, with a current of 35 A flowing in the closing spring, the known switch fails to open after as few as 300 switching cycles, as a result of the mutual bonding of the contact parts due to arcing. US 3,931,603 A discloses a temperature monitor having a bimetallic snap-action disc, a spring washer and a contact bridge. A bolt is arranged to act between the bimetallic snap-action disc and the spring washer, one end of which is secured to the bimetallic snap-action disc. The spring washer is fitted to the other end of the bolt, wherein a contact bridge is arranged on the bolt between the spring washer and the bimetallic snap-action disc, and a compression spring is arranged between the contact bridge and the bimetallic snap-action disc.

Below the switching temperature thereof, the bimetallic snap-action disc presses the bolt in the direction of two stationary counter contacts, against which the contact bridge bears under the force exerted by the compression spring, the other end of which is supported on the bimetallic snap-action disc.

If the temperature of the bimetallic snap-action disc increases, the latter withdraws the bolt from the two stationary counter contacts, wherein the bolt thus disengages the contact bridge from the counter contacts, such that the switch is opened. DE 26 25 102 A also discloses a temperature-dependent switch having a bimetallic snap-action disc, a snap-action spring disc and a contact bridge, wherein a plunger is connected at one end thereof to the snap-action spring disc, and at the other end thereof to the contact bridge, which cooperates with two stationary counter contacts.

On the side of the snap-action spring disc which is averted from the plunger, a bimetallic snap-action disc is arranged which, below the switching temperature thereof, lies loosely below the snap-action spring disc, such that the switch is closed.

If the temperature of the bimetallic snap-action disc increases, the latter is pressed against the plunger and the snap-action spring disc, such that the contact bridge disengages from the stationary counter contacts, and the snap-action spring disc switches over from its first into its second mechanically stable position. In this open state, both the snap-action spring disc and the bimetallic snap-action disc press the contact bridge away from the stationary counter contacts.

Above the contact bridge, a switching plunger is provided, which is arranged on an actuating knob via a second bistable snap-action spring disc. When the actuating knob is pressed into the housing of the switch, the switching plunger in the case of an open switch is pressed against the contact bridge. The actuating force of the second snap-action spring disc is smaller than the sum of the actuating forces of the first snap-action spring disc and the bimetallic snap-action disc such that, upon pressing the actuating knob into the housing, the second snap-action spring disc switches over to its inactive position, if the bimetallic snap-action disc lies above its switching temperature.

If the temperature of the bimetallic snap-action disc falls again, the latter springs back to its unloaded position, however the contact bridge is maintained in the open position by the first snap-action spring disc. Upon further pressing of the actuating knob, the switching plunger of the contact bridge is pressed downwards, such that the first snap-action spring disc is restored to its first stable position, in which the switch is closed. To this end, the actuating force of the second snap-action spring disc must be greater than that of the first snap-action spring disc.

From US 4,908,596 A, a temperature-dependent switch is known in which a bimetallic snap-action disc acts on a switching arm via a plunger, the free end of which carries a moveable contact part which cooperates with a stationary counter contact.

The bimetallic snap-action disc is secured to one shoulder of the housing of the temperature-dependent switch via a spring washer. The spring washer permits a snap-over of the bimetallic snap-action disc, dampens the motion of the bimetallic snap-action disc during switchover operations, and is intended to improve the exchange of heat between the bimetallic snap-action disc and the housing.

From aforementioned US 2013/0057381 A1, a temperature-dependent switch is known which, after having exceeded the switching temperature, is maintained in the open position by the snap-action spring element. By means of a manually-actuated pin, the switch can be reset to the closed position, against the force of the snap-action spring element.

In view of the prior art described, it is an object of the present invention to further develop the switch mentioned at the outset such that, with a simple and cost-effective design, the latter is capable of completing a sufficient number of switching cycles, even at higher switching currents.

According to the invention, this object is achieved in the case of the switch mentioned at the outset, in that the plunger comprises a shaft having a reduced-diameter section at its first end which has a head expanded in relation to the reduced-diameter section, wherein the bimetallic element and, where applicable, the snap-action spring element with their respective through-opening, are arranged on the reduced-diameter section, such that the bimetallic element and the snap-action spring element, where provided, are maintained in position, with clearance, between the head and the shaft, such that the snap-action spring element and the bimetallic element transmit push and forces to the plunger.

In this case, it is advantageous that the closing speed is further increased by the snap-action spring element. i As a result, the novel switch can withstand the requisite number of switching cycles, even at high switching currents.

In the context of the present invention, the term “snap-action spring element” is to be understood as a spring element having two stable geometrical configurations, of the type I generally known in the snap-action spring discs of temperature-dependent switches. By means of the bimetallic element, the snap-action spring element is pushed from its one in the direction of the other geometrically stable configuration, until the complete snap-over of the snap-action spring element takes place in an abrupt manner. i If, conversely to the known switch, the motion of the bimetallic element is transmitted to the spring element not only during the opening of the switch but also during the closing of the switch, the closing speed is increased, which according to the invention is no longer dictated by the spring element only, i.e. the closing spring. I By the conduct of tests and considerations associated with the present invention, the inventors of the present application have recognized that, under specific conditions, positive coupling between the plunger and the spring element can be omitted.

If only the snap-action spring element and the bimetallic element are connected to the i plunger, the advantage of increased opening speed is maintained. Moreover, upon the closing of the switch, the speed of withdrawal of the plunger by the combined action of the snap-action spring element and the bimetallic element is such that the closing speed is also significantly increased in comparison with the switch known from DE 10 2011 016 896 B3. i

In this manner, the object underlying the invention is entirely fulfilled.

The switch can be equipped respectively with a heating resistor for defined current-dependent switching, and additionally, where applicable, with a self-holding resistor, such that the opened switch does not cool and reclose in an automatic manner.

It is preferred that the snap-action spring element and the bimetallic element are arranged at the first end of the plunger, and the spring element at a second end of the plunger, wherein preferably the shaft has a reduced-diameter section at its second end which has a head expanded in relation to the reduced-diameter section, wherein the spring element, with a through-opening, is arranged on the reduced-diameter section such that the spring element is maintained in position, with clearance, between the head and the shaft.

These measures are structurally advantageous. They ensure that the spring element, the bimetallic element and the snap-action spring element can be secured to the plunger in a simple manner for the transmission of pull and push forces between them.

The reduced-diameter section can be configured integrally with the head or with the shaft, wherein the reduced-diameter section is either inserted into a blind hole which is provided in the shaft, or the head is fitted to the reduced-diameter section. The head can also be configured as a rivet, the bolt of which is inserted into a blind hole which is provided in the reduced-diameter section.

It is moreover preferred that the bimetallic element is configured as an elongated tongue, the opposing narrow sides of which are arranged respectively between two abutments configured in opposition in the longitudinal direction of the plunger, wherein it is additionally preferred that the snap-action spring element is configured as an elongated tongue, the opposing narrow sides of which are arranged respectively between two abutments configured in opposition in the longitudinal direction of the plunger, wherein it is additionally preferred that the bimetallic element is configured as a bimetallic disc, the edge of which is arranged between two abutments opposing each other in the longitudinal direction of the plunger, and wherein it is additionally preferred that the snap-action spring element is configured as a snap-action spring disc, the edge of which is arranged between two abutments opposing each other in the longitudinal direction of the plunger.

These measures relate to the potential configurations of the snap-action spring element and the bimetallic element as an elongated tongue or disc. In the context of the present invention, a “disc” is to be understood as any generally round, circular, oval or rounded element.

It is generally preferred that the first and second external terminals are secured to an insulating body wherein, preferably, the first and second external terminals are configured as first and second terminal sheets, the two terminal sheets project from the insulating body, and the insulating body is arranged in a housing, wherein it is moreover preferred that the spring element has a first and a second branch, the moveable contact part is secured to the first branch, the second branch is electrically connected to the second terminal sheet and the plunger is arranged between the first branch and the bimetallic element, wherein it is moreover preferred that the housing has an upper side and a lower side, which are interconnected by means of narrow sides, and the housing is provided with an opening on one of its narrow sides, and is fitted onto the insulating body by means of said opening, wherein it is moreover preferred that the two branches are bent away from each other by the plunger for the interruption of a conductive connection between the two terminal sheets, wherein it is moreover preferred that the second branch bears on the second terminal sheet, wherein it is moreover preferred that the insulating body is comprised of two subsections, and the two terminal sheets are arranged between the two subsections.

It is moreover preferred that the bimetallic element is arranged in a recess in an outer surface of the insulating body, wherein it is moreover preferred that the snap-action spring element is arranged in a recess in an outer surface of the insulating body, and finally the recess is provided with an externally-inserted ring, which serves as an abutment for the snap-action spring element and/or the bimetallic element.

These measures are structurally advantageous, as they result in a compact and cost-effective switch.

It is preferred that the bimetallic element is arranged between the plunger and the snap-action spring element.

In this case, it is advantageous that the snap-action spring element bears externally on the bimetallic element, and protects the latter.

Alternatively, it is preferred that the snap-action spring element is arranged between the plunger and the bimetallic element.

In this case, it is firstly advantageous that an effective thermal coupling can be achieved between the outward-lying bimetallic element and a device to be protected, wherein it is additionally advantageous that, even in the absence of a positive coupling between the plunger and the bimetallic element and the snap-action spring element, the bimetallic element effects the very rapid snap-over of the snap-action spring element overlaying it in the direction of the plunger, upon the opening of the switch.

Further advantages emerge from the description and the attached drawing.

It is understood that the aforementioned features, and those described hereinafter, can not only be used in the respective combination indicated, but also in other combinations, or in isolation, without departing from the scope of the present invention.

Embodiments of the invention are represented in the attached drawing, and are described in greater detail in the description hereinafter. Herein:

Fig. 1 shows a schematic longitudinal section, not to scale, of a first embodiment of a temperature-dependent switch, in which in a switching mechanism a moveable contact part cooperates with a stationary contact part, and in which a plunger is arranged between a bimetallic element and a spring element;

Fig. 2 shows a schematic exploded view of a switch which employs the switching mechanism represented in Fig. 1;

Fig. 3 shows the assembled switch represented in Fig. 2, in a longitudinal section;

Fig. 4 shows an overhead view of the switch represented in Fig. 3, but without the housing;

Fig. 5 shows a second embodiment of the temperature-dependent switch, in the manner represented in Fig. 1; and

Fig. 6 shows an embodiment of the temperature-dependent switch which is not included in the present invention, in the manner represented in Fig. 1.

Fig. 1 shows a highly schematic representation of a first embodiment of a temperature-dependent switch 10, comprising a first and a second external terminal 11,12 and a switching mechanism 14 which, in temperature-dependent manner, makes or breaks an electrically-conductive connection between the external terminals 11, 12.

The switching mechanism 14 comprises a stationary contact part 15 which is connected to the first external terminal 11 in an electrically conductive manner, and a moveable contact part 16 which cooperates with the stationary contact part 15 and is secured to a spring element 17, which is connected to the second external terminal 12 in an electrically conductive manner and acts as a closing spring which presses the moveable contact part 16 against the stationary contact part 15.

In this simplified embodiment, the spring element 17 is configured as a leaf spring which, in the region of the second external terminal 12, is attached to a schematically-represented insulating body 18, to which both the first external terminal 11 and the stationary contact part 15 are also attached.

The switching mechanism 14 moreover comprises a bimetallic element 19 and a plunger 21 arranged between the bimetallic element 19 and the spring element 17. The spring element 17 and the bimetallic element 19 are arranged at opposing ends 20a and 20b of the plunger 21.

In a known manner, in the event of exceeding of a switching temperature, the bimetallic element 19 presses the plunger 21 against the spring element 17, thus disengaging the moveable contact part 16 from the stationary contact part 15.

In the embodiment represented, the bimetallic element 19 is configured as an elongated tongue, the opposing narrow sides 22 and 23 of which, with respective sufficient mechanical clearance for the snap-over, are arranged between two opposing abutments 25, 26 opposing each other in the longitudinal direction 24 of the plunger 21. The upper abutments 25 are configured as part of the insulating body 18, whereas the lower abutments 26 are configured as a retaining ring for the bimetallic element 19.

For the purposes of pulling and pushing, the plunger 21 is connected by means of an upper head 27 and a lower head 28 to the spring element 17 and the bimetallic element 19 respectively. Between a shaft 29 of the plunger 21 and the lower head 28, a reduced-diameter section 31 is provided, upon which the bimetallic element 17 is seated, with a clearance. The spring element 17 can also be arranged on the plunger 21, with a clearance. The head 27 and the head 28 are expanded in relation to the reduced-diameter section 31 and the shaft 29.

The shaft 29 of the plunger is routed in a through-opening 30 which is provided in the insulating element 18, for the protection thereof against misalignment and/or jamming.

In the switching state represented in Fig. 1, the switch 10 is closed. The spring element 17 presses the moveable contact part 16 against the stationary contact part 15, such that the electrical circuit is closed between the two external terminals 11,12 and the operating current of a device to be protected flows in the spring element 17.

The narrow sides 22, 23 of the bimetallic element, which is in its first geometrical configuration, bear on the upper abutment 25, and thus support the closing pressure with which the moveable contact part 16 is pressed against the stationary contact part 15.

In the event of exceeding of its switching or response temperature, the bimetallic element 17 snaps into its other geometrical configuration, such that the narrow sides 22, 23 engage with the lower abutment 26, and the bimetallic element 17 thus presses the plunger 21 represented in Fig. 1 upwards, in the direction of the arrow 32. As a result, the plunger 21 presses the spring element 17 upwards, such that the moveable contact part 16 is disengaged from the stationary contact part 15, and the electrical circuit is opened.

If the temperature of the bimetallic element 19 falls once more, it snaps back into its first geometrical configuration represented in Fig. 1. Via the plunger, it thus exerts a downward pull force upon the spring element 17 in the direction of the arrow 32, as a result of which the closing speed with which the moveable contact part 16 re-engages with the stationary contact part 15 is increased, in comparison with a design of the switching mechanism 14 in which the bimetallic element 19 exerts only a push force upon the spring element 17.

In parallel with the bimetallic element 19, a snap-action spring element 33, also configured as an elongated tongue, is arranged at the end 20b of the plunger 21, the opposing narrow sides 34 and 35 of which are likewise arranged, with a clearance, between the abutments 25 and 26. The snap-action spring element is likewise seated, with a clearance, on the reduced-diameter section 31 of the plunger 21, such that it can transmit push and pull forces to the spring element 17 via the plunger.

The snap-action spring element 33 can thus be arranged, either between the bimetallic element 19 and the plunger 21, or on the side of the bimetallic element 19 which is averted from the plunger 21, as represented in Figs. 1 to 5.

The snap-action spring element 33 further enhances the switching dynamics of the switching mechanism 14. In the manner described above, firstly, the closing speed is further increased as, upon the closing of the switch 10, the snap-action spring element 33 also executes a snap-over from one stable configuration thereof, in which the narrow sides 34, 35 bear on the abutments 26, back to its other stable configuration, in which the narrow sides are supported on the abutments 25. Like the the bimetallic element 19, the snap-action spring element 33 thus exerts a pull force upon the spring element 17 via the plunger 21.

The snap-over of the snap-action spring element 33 between its two stable geometrical configurations is triggered by the temperature-dependent snap-over of the bimetallic element 19 between its two geometrical configurations.

As the snap-action spring element 33 also exerts a push force upon the spring element 17, the opening speed with which the moveable contact part 16 disengages from the stationary contact part 15 is also increased, when the switch 10 is opened by the snap-over of the bimetallic element 19.

Fig. 2 shows an exploded diagram of a specific embodiment of the switch 10 represented in Fig. 1.

The switch 10 comprises a two-part insulating body 18, having an upper part 18a and a lower part 18b. The first external terminal 11 is configured as a terminal sheet 36, which supports the stationary contact part 15. The second external terminal 12 is configured as a terminal sheet 37, which is connected in an electrically conductive manner to the spring element 17 which, in this case, has a first branch 38 to which the moveable contact part 16 is attached.

The spring element 17 moreover has a second branch 39, which is arranged in parallel with the first branch 38 and is configured with a laterally-projecting side wing 41 which, in the assembled state, comes to bear on the second terminal sheet 37.

Upon the assembly of the switch 10, the terminal sheets 36, 37, and the spring element 17 arranged above the latter, are sandwiched between the upper part 18a and the lower part 18b of the insulating body 18, such that the terminal sheets 36, 37 project laterally from the insulating body 18, as can be seen from the overhead view of the assembled switch 10 represented in Fig. 4.

The insulating body 18 is then inserted in aflat housing 42, which is represented in Fig. 2, having an upper side 43 and a lower side 44 which are interconnected by means of narrow sides 45, wherein the housing, on one of its narrow sides 45, is configured with an opening 46 and is fitted onto the insulating body 18 by means of said opening 46, as can be seen in Fig. 3.

The bimetallic element 19 is configured as a bimetallic disc 47, and the snap-action spring element 33 as a snap-action spring disc 48. Both discs are configured with an edge 51 and 52, respectively, and are inserted in an outwardly open recess 53 in the lower outer surface 18c of the lower part 18b, such that they are supported on circumferential abutments 25a or 25b of the lower part 18b, when the switch 10 is closed.

In the recess 53, a ring 54 is inserted, which extends radially inwards beyond the edges 51,52 and forms the abutment 26 on which the bimetallic disc 47 and the snap-action spring disc 48 are supported at their respective edges 51,52, when they open the switch 10.

Between the abutments 25 and 26, the edges 51 and 52 are arranged with a mechanical clearance, in order to permit the expansion of the bimetallic disc 47 and the snap-action spring disc 48 upon the snap-over from one geometrical configuration to the other thereof.

The plunger 21 comprises the shaft 29 having the lower reduced-diameter section 31, to which the bimetallic disc 47 and the snap-action spring disc 48 are fitted, with a clearance, by means of their respective through-opening 55 and 56, respectively.

After assembly, the plunger 21 passes through the through-opening 30 which is configured in the lower part 18b.

The head 27 is provided with a bolt 57, and the head 28 is provided with a bolt 58. The bolt 57 is seated in an upper blind hole 61 in the shaft 29 and the bolt 58 in a lower blind hole 62 in the reduced-diameter section 31, wherein the heads 27 and 28 are configured with an enlarged diameter in relation to the bolts 57 and 59, and to the shaft 29.

The first branch 38 is provided with a through-opening 63, by means of which it is arranged on the bolt 57, with a clearance.

In this manner, the first branch 38 and the bimetallic disc 47, together with the snap-action spring disc 48, are interconnected for the purposes of pulling and and pushing.

If, upon the opening of the switch 10, the plunger 21 is pressed upwards, it bends the two branches 38, 39 of the spring element 17 apart.

Fig. 5 shows a second embodiment of a switch 10’, and Fig. 6 shows an embodiment of a switch 10” which is not included in the present invention, each in the manner represented in Fig. 1. The same reference numbers are used to identify identical features having identical properties such that, in respect of the design principle and the operating principle, reference is made to the preceding description of Fig. 1.

The switch 10’ represented in Fig. 5 has only the lower head 28, by means of which the bimetallic element 19 and the snap-action spring element 33 are connected to the plunger 21 such that the latter is moved upwards and downwards, in the direction of the arrow 32 shown in Fig. 5, when the bimetallic element 19 and, in consequence, the snap-action spring element 33, executes a snap-over from one respective geometrical configuration thereof to the other.

Although the head 27 is omitted, there is no resulting risk of the misalignment or jamming of the plunger 21, as it is routed through the through-opening 30.

The spring element 17 lies in contact with the upper end 20a of the plunger 21 such that, upon the opening of the switch 20a, it is very rapidly pressed upwards by the combined push force of the bimetallic element 19 and the spring element 33.

Upon the closing of the switch 10’, the bimetallic element 19 springs back to its configuration represented in Fig. 5, and thus pulls the plunger 21 downwards. By this action, as the snap-action spring element 33 is also connected to the plunger 21, it is initially pressed downwards at the point where it engages with the plunger 21, until it likewise springs back to its other stable geometrical configuration, as represented in Fig. 5.

The spring element 17 is not actively drawn down by the plunger 17, as the head 27 represented in Fig. 1 is not provided in this case. The switch 10’ nevertheless closes more rapidly than a switch with no positive coupling between the plunger 21 and the bimetallic element 19 and the snap-action spring element 33, as the speed of the downward motion of the plunger 21 is such that no counter-resistance to the closing motion of the spring element 17 is provided.

In the switch 10’, both the opening speed and the closing speed are thus increased in comparison with a switch in which only a bimetallic element 19 is provided which, moreover, has no positive coupling with the plunger 21.

As the head 27 is omitted from the switch 10’, the assembly thereof is simpler than that of the switch 10 represented in Figs. 1 to 4.

During assembly, the insulating body 18 is firstly combined, such that the two terminal sheets 36, 37 and the spring element 17 are sandwiched between the upper part 18a and the lower part 18b.

The plunger 21 is then permanently connected to the bimetallic element 19 and the snap-action spring element 33 by means of the head 28, and this unit, as represented in Fig. 2, is then inserted from below into the preassembled insulating body 18, i.e. into the recess 53 in the lower part 18b. The upper end 20a of the plunger is thus routed through the through hole 30, such that said upper end 20a comes to bear on the first branch 38.

In the switch 10” represented in Fig. 6, the lower head 28 is also omitted. In a further distinction from switches 10 and 10’, the bimetallic element 19 in the switch 10” is arranged below the snap-action spring element 33.

Although both the heads 27, 28 are omitted, there is likewise no resulting risk of the misalignment or jamming of the plunger 21, as it is routed through the through-opening 30.

If the temperature of the bimetallic element 19 rises in excess of its snap-over temperature, the bimetallic element 19 executes a snap-over from the low-temperature configuration represented in Fig. 6 to its other geometrical configuration. It thus exerts a central pressure upon the snap-action spring element 33, the centre of which is thus gradually raised until it executes an abrupt snap-over to its other geometrically stable configuration and, in combination with the bimetallic element 19, abruptly presses the plunger represented in Fig. 6 upwards.

The spring element 17 lies in contact with the upper end 20a of the plunger 21 such that, upon the opening of the switch 20a, it is likewise pressed upwards in a very rapid manner by the combined push force of the bimetallic element 19 and the spring element 33.

During closing of the switch 10’, the bimetallic element 19 springs back to its configuration represented in Fig. 6. Via the plunger 21, the spring element 17 exerts pressure upon the snap-action spring element 33, and presses the latter downwards at the point where it engages with the plunger 21, until it likewise springs back to its other stable geometrical configuration, represented in Fig. 6.

The spring element 17 is here not actively drawn down by the plunger 21, as the head 27 represented in Fig. 1 is again not provided in this case. The switch 10’ nevertheless not only opens more rapidly than a switch with no snap-action spring element 33 but, with a corresponding design, can also close more rapidly. This more rapid closing is achieved on the grounds that, further to the snap-over of the snap-action spring element 33, the speed of the downward motion of the bimetallic element 19 is such that it provides no further counter-resistance to the plunger 21, once the latter has been displaced completely downwards again by the closing motion of the spring element 17 to the position represented in Fig. 6.

In the switch 10”, at least the opening speed is thus increased, in comparison with a switch in which only a bimetallic element 19 is provided.

As the head 27 is omitted from the switch 10”, the assembly thereof is simpler than that of the switch 10 represented in Figs. 1 to 4.

The insulating body 18 is firstly assembled, such that the two terminal sheets 36, 37 and the spring element 17 are sandwiched between the upper part 18a and the lower part 18b.

The upper end 20a of the plunger 21 is then routed through the through hole 30, such that said upper end 20a comes to bear on the installation with the first branch 38. The snap-action spring element 33, and thereafter the bimetallic element 19, are then inserted in the recess 53.

Claims

1. Temperaturafhængig omskifter med en første og en anden udvendig tilslutning (11, 12), en stationær kontaktdel (15), der er forbundet elektrisk ledende med den første udvendige tilslutning (11), en bevægelig kontaktdel (16), der samvirker med den stationære kontaktdel (15), som er fastgjort på en fjederdel (17), som er forbundet elektrisk ledende med den anden udvendige tilslutning (12), og som trykker den bevægelige kontaktdel (16) mod den stationære kontaktdel (15), en bimetaldel (19) og et stempel (21), der er anbragt mellem bimetaldelen (19) og fjederdelen (17), hvor bimetaldelen (19) trykker stemplet (21) mod fjederdelen (17), når en omskiftningstemperatur overskrides, og derved løfter den bevægelige kontaktdel (16) op fra den stationære kontaktdel (15), og med en fjedersnapdel (33), som trykker stemplet (21) mod fjederdelen (17), i det mindste når omskiftningstemperaturen overskrides, kendetegnet ved, at stemplet (21) har en stang (29), som ved sin første ende (20b) har en tilspidset sektion (31), som bærer et hoved (28), som er udvidet i forhold til den tilspidsede sektion (31), hvor bimetaldelen (19) og fjedersnapdelen (33) er anbragt på den tilspidsede sektion (31) med deres respektive gennemgangshul (55, 56) på en sådan måde, at bimetaldelen (19) og fjedersnapdelen (33) holdes med frigang mellem hovedet (28) og stangen (29), således at fjedersnapdelen (33) og bimetaldelen (19) overfører tryk- og trækkræfter til stemplet (21).A temperature dependent switch having a first and a second external connection (11, 12), a stationary contact part (15) connected electrically conductive to the first external connection (11), a movable contact part (16) cooperating with the stationary contact part (15), which is attached to a spring part (17) which is electrically conductive to the other external connection (12) and which presses the movable contact part (16) against the stationary contact part (15), a bimetal part ( 19) and a piston (21) disposed between the bimetal part (19) and the spring part (17), where the bimetal part (19) presses the piston (21) against the spring part (17) when a switching temperature is exceeded, thereby raising the movable contact part (16) from the stationary contact portion (15), and with a spring snap portion (33) pushing the plunger (21) against the spring portion (17), at least when the switching temperature is exceeded, characterized in that the plunger (21) has a rod (29), which at its first end (2 0b) has a tapered section (31) carrying a head (28) extended relative to the tapered section (31), with the bimetal portion (19) and the spring snap portion (33) disposed on the tapered section (31). with their respective through-holes (55, 56) in such a way that the bimetal portion (19) and the spring snap portion (33) are held at clearance between the head (28) and the rod (29) so that the spring snap portion (33) and the bimetal portion (19) compressive and tensile forces for the piston (21).

2. Temperaturafhængig omskifter ifølge krav 1, kendetegnet ved, at fjedersnapdelen (33) og bimetaldelen (19) er anbragt ved den første ende (20b) af stemplet (21), og fjederdelen (17) er anbragt ved en anden anden (20a) af stemplet (21).Temperature dependent switch according to claim 1, characterized in that the spring snap part (33) and the bimetal part (19) are arranged at the first end (20b) of the piston (21) and the spring part (17) is arranged at another second (20a). of the plunger (21).

3. Temperaturafhængig omskifter ifølge krav 1 eller 2, kendetegnet ved, at bimetaldelen (19) er anbragt mellem stemplet (21) og fjedersnapdelen (33).Temperature dependent switch according to claim 1 or 2, characterized in that the bimetal part (19) is arranged between the piston (21) and the spring snap part (33).

4. Temperaturafhængig omskifter ifølge krav 1 eller 2, kendetegnet ved, at fjedersnapdelen (33) er anbragt mellem stemplet (21) og bimetaldelen (19).Temperature dependent switch according to claim 1 or 2, characterized in that the spring snap part (33) is arranged between the piston (21) and the bimetal part (19).

5. Temperaturafhængig omskifter ifølge et af kravene 1 til 4, kendetegnet ved, at stangen (29) ved sin anden ende (20a) har en tilspidset sektion, som bærer et hoved (27), der er udvidet i forhold til denne tilspidsede sektion, hvor fjederdelen (17) er anbragt på denne tilspidsede sektion med et gennemgangshul (63) på en sådan måde, at fjederdelen (17) holdes med frigang mellem dette hoved (27) og stangen (29).Temperature dependent switch according to one of claims 1 to 4, characterized in that the rod (29) has at its other end (20a) a tapered section carrying a head (27) which is extended relative to this tapered section. wherein the spring portion (17) is disposed on this tapered section with a through-hole (63) in such a way that the spring portion (17) is held in clearance between said head (27) and the rod (29).

6. Temperaturafhængig omskifter ifølge et af kravene 1 til 5, kendetegnet ved, at bimetaldelen (19) er udformet som en aflang tunge, som ved sine over for hinanden liggende smalle sider (22, 23) respektivt er anbragt mellem to modlejer (25, 26), som ligger over for hinanden i stemplets (21) længderetning (24).Temperature dependent switch according to one of claims 1 to 5, characterized in that the bimetal part (19) is formed as an elongated tongue, which at its opposite narrow sides (22, 23) are respectively arranged between two counter bearings (25, 26) which are opposite to each other in the longitudinal direction (24) of the piston (21).

7. Temperaturafhængig omskifter ifølge et af kravene 1 til 6, kendetegnet ved, at fjedersnapdelen (33) er udformet som en aflang tunge, som ved sine over for hinanden liggende smalle sider (34, 35) respektivt er anbragt mellem to modlejer (25, 26), som ligger over for hinanden i stemplets (21) længderetning (24).Temperature dependent switch according to one of claims 1 to 6, characterized in that the spring snap part (33) is formed as an elongated tongue, which is arranged at its opposite narrow sides (34, 35), respectively, between two counter-bearings (25, 26) which are opposite to each other in the longitudinal direction (24) of the piston (21).

8. Temperaturafhængig omskifter ifølge et af kravene 1 til 5 eller 7, kendetegnet ved, at bimetaldelen (19) er udformet som en bimetal-skive (47), som ved sin kant (51) er anbragt mellem to modlejer (25a, 54), som ligger over for hinanden i stemplets (21) længderetning (24).Temperature dependent switch according to one of claims 1 to 5 or 7, characterized in that the bimetal part (19) is formed as a bimetal disc (47), which is arranged at its edge (51) between two counter-bearings (25a, 54). which are opposite to each other in the longitudinal direction (24) of the piston (21).

9. Temperaturafhængig omskifter ifølge et af kravene 1 til 6 eller 8, kendetegnet ved, at fjedersnapdelen (33) er udformet som en fjeder-snapskive (48), som ved sin kant (52) er anbragt mellem to modlejer (25b, 54), som ligger over for hinanden i stemplets (21) længderetning (24).Temperature dependent switch according to one of claims 1 to 6 or 8, characterized in that the spring snap part (33) is formed as a spring snap disc (48), which at its edge (52) is arranged between two counter bearings (25b, 54). which are opposite to each other in the longitudinal direction (24) of the piston (21).

10. Temperaturafhængig omskifter ifølge et af kravene 1 til 9, kendetegnet ved, at den første og anden udvendige tilslutning (11, 12) er fastgjort på et isoleringslegeme (18).Temperature dependent switch according to one of claims 1 to 9, characterized in that the first and second external connections (11, 12) are fixed to an insulating body (18).

11. Temperaturafhængig omskifter ifølge krav 10, kendetegnet ved, at den første og den anden udvendige tilslutning (11, 12) er udformet som en hhv. første og anden tilslutningsplade (36, 37), de to tilslutningsplader (36, 37) rager ud fra isoleringslegemet (18), og isoleringslegemet (18) er anbragt i et hus (43).Temperature dependent switch according to Claim 10, characterized in that the first and the second external connection (11, 12) are designed as one and a half, respectively. first and second connection plates (36, 37), the two connection plates (36, 37) protrude from the insulating body (18) and the insulating body (18) is arranged in a housing (43).

12. Temperaturafhængig omskifter ifølge krav 11, kendetegnet ved, at fjederdelen (17) har et første og et andet ben (38, 39), den bevægelige kontaktdel (16) er fastgjort på det første ben (38), det andet ben (39) er forbundet elektrisk med den anden tilslutningsplade (37), og stemplet (21) er anbragt mellem det første ben (38) og bimetaldelen (19).Temperature dependent switch according to claim 11, characterized in that the spring part (17) has a first and a second leg (38, 39), the movable contact part (16) is fixed to the first leg (38), the second leg (39) ) is electrically connected to the second connection plate (37) and the piston (21) is arranged between the first leg (38) and the bimetal part (19).

13. Temperaturafhængig omskifter ifølge krav 11 eller 12, kendetegnet ved, at huset (42) har en overside (43) og en underside (44), som er forbundet med hinanden via smalle sider (45), og huset ved en af dets smalle sider (45) har en åbning (46) og med denne åbning (46) er sat fast på isoleringslegemet (18).Temperature dependent switch according to claim 11 or 12, characterized in that the housing (42) has an upper side (43) and a lower side (44) which are connected to each other via narrow sides (45) and the housing at one of its narrow sides. sides (45) have an opening (46) and with this opening (46) are fixed to the insulating body (18).

14. Temperaturafhængig omskifter ifølge krav 12 eller 13, kendetegnet ved, at de to ben (38, 39) bøjes væk fra hinanden af stemplet (21) for at afbryde en ledende forbindelse mellem de to tilslutningsplader (36, 37).Temperature dependent switch according to claim 12 or 13, characterized in that the two legs (38, 39) are bent away from each other by the piston (21) to interrupt a conductive connection between the two connection plates (36, 37).

15. Temperaturafhængig omskifter ifølge et af kravene 12 til 14, kendetegnet ved, at det andet ben (39) ligger an mod den anden tilslutningsplade (37).Temperature dependent switch according to one of claims 12 to 14, characterized in that the second leg (39) abuts the second connection plate (37).

16. Temperaturafhængig omskifter ifølge et af kravene 11 til 15, kendetegnet ved, at isoleringslegemet (18) er sammensat af to delelementer (18a, 18b), og de to tilslutningsplader (36, 37) ligger mellem de to delelementer (18a, 18b).Temperature dependent switch according to one of claims 11 to 15, characterized in that the insulating body (18) is composed of two sub-elements (18a, 18b) and the two connection plates (36, 37) are between the two sub-elements (18a, 18b). .

17. Temperaturafhængig omskifter ifølge et af kravene 10 til 16, kendetegnet ved, at bimetaldelen (19) er anbragt i en fordybning (53) ved en udvendig side (18c) af isoleringslegemet (18).Temperature dependent switch according to one of claims 10 to 16, characterized in that the bimetal part (19) is arranged in a recess (53) at an outer side (18c) of the insulating body (18).

18. Temperaturafhængig omskifter ifølge et af kravene 10 til 17, kendetegnet ved, at fjedersnapdelen (33) er anbragt i en fordybning (53) ved en ud- vendig side (18c) af isoleringslegemet (18).Temperature dependent switch according to one of claims 10 to 17, characterized in that the spring snap member (33) is arranged in a recess (53) at an external side (18c) of the insulating body (18).

19. Temperaturafhængig omskifter ifølge krav 17 eller 18, kendetegnet ved, at der i fordybningen (53) er tilvejebragt en ring (54) indsat udvendigt fra, som tjener som modleje for fjedersnapdelen (33) og/eller bimetaldelen (19).Temperature dependent switch according to claim 17 or 18, characterized in that in the recess (53) is provided a ring (54) inserted from the outside, which serves as a counter bearing for the spring snap part (33) and / or bimetal part (19).