Bimetal controller

Abstract

A bimetallic controller, having a switching device and at least one bimetal device which is or can be actively connected to the switching device such as to allow the switching device to be switched in a temperature-dependent fashion. The bimetal device includes at least one first bimetal element and at least one curved second bimetal element that are connected to each other in a zone of contact and are designed in said zone of contact such that the coefficient of thermal expansion of the first bimetal element increases from its bottom to the top and the coefficient of thermal expansion of the curved second bimetal element decreases from its bottom to the top, or vice versa.

Claims

1. A bimetal controller for temperature-dependent switching, the bimetal controller comprising: a switching device; and a bimetal device connected to the switching device for switching the switching device responsive to a change in an ambient temperature, the bimetal device and the switching device being electrically isolated from each other, the bimetal device comprising a first bimetal element and a second bimetal element, the first bimetal element comprising an elongate shape, the second bimetal element comprising an arcuate shape; the second bimetal element being attached solely to a free end of first bimetal element at a contact region, the first bimetal element comprising a first movement responsive to the change in the ambient temperature, the first movement being in a first direction the second bimetal element comprising a second movement responsive to the change in the ambient temperature, the second movement being in a second direction, the first direction and the second direction being a same direction, and the first movement and the second movement being additive to form a switching movement; wherein in the contact region a coefficient of thermal expansion of the first bimetal element decreases from an underside of the first bimetal element to an upper side of the first bimetal element and a coefficient of thermal expansion of the second bimetal element increases from an underside of the second bimetal element to the upper side of the second bimetal element, or the coefficient of thermal expansion of the first bimetal element increases from the underside the first bimetal element to the upper side of the first bimetal element and the coefficient of thermal expansion of the second bimetal element decreases from the underside of the second bimetal element to the upper side of the second bimetal element.

2. The bimetal controller as claimed in claim 1, wherein each of the first bimetal element and the second bimetal element comprise a layer structure, each layer structure comprising a plurality of element layers, each element layer comprising a respective different coefficient of thermal expansion (.sub.T10, .sub.T12) than another element layer in the respective bimetal element, wherein the coefficients of thermal expansion (.sub.T10, .sub.T12) in the layer structure of the first bimetal element at the contact region progress oppositely to the coefficients of thermal expansion (.sub.T10, .sub.T12) in the layer structure of second bimetal element.

3. The bimetal controller as claimed in claim 1, wherein the first bimetal element or second bimetal element are formed as a bimetal strip.

4. The bimetal controller as claimed in claim 1, wherein the contact region is arranged at a distal end of the first bimetal element and a proximal end of the second bimetal element.

5. The bimetal controller as claimed in claim 1, wherein the second bimetal element comprises a substantially linearly formed switching region connected to the switching device, the switching region being disposed at a distal end of the arcuate shape.

6. The bimetal controller as claimed in claim 5, wherein the switching region comprises a principal axis, the arcuate shape comprises a tangent, wherein an angle defined by an intersection of the principal axis and the tangent is less than 180 degrees.

7. A connection apparatus for temperature-dependent switching, the apparatus comprising: the bimetal controller of claim 1; a housing for housing the bimetal controller; a clamping bolt and a clamping bolt receptacle jointly defining a clamping space inside the housing; a conducting element extending from an exterior of the housing into the clamping space; a contact element protruding into the clamping space, wherein the clamping bolt being held in an axial direction of the clamping bolt in the housing and lying with a clamping continuation against the contact element in an unconstrained manner, wherein a counter bearing region of the clamping bolt receptacle is moveable toward the clamping continuation and the contact element lying on the clamping bolt while reducing the clamping space and immovable at least in one clamping position such that the conducting element and the contact element are fixed with respect to each other in an electrically conducting manner, without a flexural loading being introduced into the contact element.

8. The bimetal controller as claimed in claim 1, wherein the first bimetal element and the second bimetal element are arranged in series in a meandering series.

9. A bimetal controller for temperature-dependent switching of a switching device, the bimetal controller comprising: a switching element actuating the switching device; and a first bimetal element and a second bimetal element, the second bimetal element having a proximal end and a distal end, the distal end being unsupported, the proximal end being attached only to a free end, the proximal end and the free end defining a contact region, the first bimetal element comprising an elongate shape, the second bimetal element comprising an arcuate shape disposed between the proximal end and the distal end; wherein, responsive to a change in an ambient temperature, the first bimetal element comprises a first movement in a first direction and the second bimetal element comprises a second movement in a second direction, the first direction and the second direction being a same direction, and the first movement and the second movement being additive to displace the distal end to move the switching element in order to actuate the switching device; wherein, in the contact region, a coefficient of thermal expansion of the first bimetal element decreases from an underside of the first bimetal element to an upper side of the first bimetal element and a coefficient of thermal expansion of the second bimetal element increases from an underside of the second bimetal element to the upper side of the second bimetal element, or the coefficient of thermal expansion of the first bimetal element increases from the underside the first bimetal element to the upper side of the first bimetal element and the coefficient of thermal expansion of the second bimetal element decreases from the underside of the second bimetal element to the upper side of the second bimetal element; wherein the first bimetal element and the second bimetal element are electrically isolated from the switching element.

10. The bimetal controller as claimed in claim 9, wherein each of the first bimetal element and the second bimetal element comprises a layer structure, each layer structure comprising a plurality of element layers, each element layer comprising a respective different coefficient of thermal expansion (.sub.T10, .sub.T12) than another element layer in the respective bimetal element, wherein the coefficients of thermal expansion (.sub.T10, .sub.T12) in the layer structure of the first bimetal element at the contact region progress oppositely to the coefficients of thermal expansion (.sub.T10, .sub.T12) in the layer structure of second bimetal element.

11. The bimetal controller as claimed in claim 9, wherein the first bimetal element or second bimetal element are formed as a bimetal strip.

12. The bimetal controller as claimed in claim 9, wherein the contact region is arranged at a distal end of the first bimetal element and the proximal end of the second bimetal element.

13. The bimetal controller as claimed in claim 9, wherein the distal end is substantially linear and is disposed in contact with the switching element.

14. The bimetal controller as claimed in claim 13, wherein the distal end comprises a principal axis, the arcuate shape comprises a tangent, wherein an angle defined by an intersection of the principal axis and the tangent is less than 180 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below on the basis of exemplary embodiments, which are explained in more detail by the accompanying drawings, in which:

(2) FIG. 1 shows an isometric representation of an embodiment of the bimetal controller;

(3) FIG. 2 shows a side view of the embodiment of the bimetal controller from FIG. 1;

(4) FIG. 3 shows the view of a detail of a bimetal device of the embodiment of the bimetal controller from FIG. 1;

(5) FIG. 4 shows a further embodiment of a bimetal device;

(6) FIG. 5 shows an isometric representation of the embodiment of the bimetal controller according to FIG. 1 with paternoster connection terminals;

(7) FIG. 6 shows an isometric longitudinal section of the representation from FIG. 5; and

(8) FIG. 7 shows an isometric longitudinal section of the embodiment of the bimetal controller according to FIG. 5 when integrated in a housing.

DETAILED DESCRIPTION

(9) The same reference signs are used hereafter for components that are the same and components that act in the same way, superscripts sometimes being used for the purpose of distinction.

(10) FIG. 1 shows an isometric representation of an embodiment of the bimetal controller according to the invention, FIG. 2 shows a side view of this embodiment and FIG. 3 shows a representation of a detail of a bimetal device 4, such as that used in this bimetal controller 1.

(11) In the case of this embodiment, the bimetal device 4 has two bimetal elements 6, 8, to be specific a first bimetal element 6 and an arcuate, second bimetal element 8. The arcuate, second bimetal element is configured here at least partially in the form of a circle. These two bimetal elements 6, 8 are connected to each other at a contact region 14, in particular here the first bimetal element 6 is arranged with its distal end 7 on the proximal end 9 of the arcuate, second bimetal element 8.

(12) The bimetal device 4 is actively connected by way of a switching element 3 to a switching device 2, which establishes an electrical connection between two contact elements 16, 18, that is to say allows a switching operation. An adjustment of the switching operation can be made by way of a setting element 20, in that two switching contacts 17, 19 assigned to the contact elements 16, 18 are positioned in relation to each other. Depending on how this positioning is performed, the switching device 2 triggers the switching operation when there are small or greater movements of the bimetal device 4.

(13) The bimetal device 4 is restrained in a substantially flexurally rigid manner by a proximal end 5 of the first bimetal element 6 on a bearing block 22. This bearing block, which consists of a number of isolating individual elements 23, carries not only the bimetal device 4 but also the contact elements 16 and 18 and a retaining plate 24, which allows the bimetal controller 1 to be fastened in a housing 40 (see FIG. 7) and additionally carries the setting elements 20.

(14) The arcuate, second bimetal element 8 has at its distal end 11 a switching region 13, by way of which it is actively connected to the switching device 2 by the switching element 3. When there is a change in temperature, the switching region 13 moves on account of the resulting movement of the two bimetal elements 6, 8 toward the switching device 2, the switching element 3 triggering the switching operation when there is a specific movement.

(15) The structure of the switching device 2 can be seen in detail in FIG. 2 in particular. It comprises the two contact elements 16 and 18, which can be brought into electrically conducting connection with each other via the assigned contact elements 17 and 19 by an activation taking place by way of the switching element 3. The contact element 17 is formed here as a spring element, and in particular as a beryllium-sprung spring element, so that the electrical conducting connection is opened again when there is a retraction of the switching element 3.

(16) In FIGS. 1 and 2, and in particular in FIG. 3, the different layer structures of the two bimetal elements 6, 8 of the bimetal device 4 can be seen. The first bimetal element 6 consists of two element layers 10, 12, element layer 10 with the greater coefficient of thermal expansion .alpha..sub..DELTA.T10 being arranged on the underside 21, as represented in the plane of the drawing, and the element layer 12 with the lower coefficient of thermal expansion .alpha..sub..DELTA.T12 being arranged on the upper side 23.

(17) The layer structure of the arcuate, second bimetal element 8 is formed oppositely thereto. This bimetal element 8 also consists of two element layers 10, 12, the element layer 10 with the higher coefficient of thermal expansion .alpha..sub..DELTA.T10 being arranged on the upper side 23, as represented in the plane of the drawing, and the element layer 12 with the lower coefficient of thermal expansion .alpha..sub..DELTA.T12 being arranged on the underside 21 in the contact region 14.

(18) The result of such an opposed arrangement of the two layer structures of the two bimetal elements 6, 8 is a very much stronger deflection (represented here in FIG. 3 by the arrow 26), which in the case of the bimetal controller 1 represented here leads to a very much more accurate adjustability and more accurate switchability.

(19) In FIG. 3, the movement of the bimetal device 4 or of the two bimetal elements 6, 8 when there is a specific change in temperature .DELTA.T is represented diagrammatically, the final position of the bimetal device 4 when there is a change in temperature .DELTA.T being represented by dashed lines.

(20) FIG. 4 shows a further embodiment of the bimetal device 4, here a plurality of first bimetal elements 6 and arcuate, second bimetal elements 8 being arranged alongside one another in series and here in particular in a meandering form. In this way, the switching travel 26 represented in FIG. 3 when there is a change in temperature .DELTA.T can be increased almost at will, allowing unwanted movements, here for example the drift to the right of the switching region 13 depicted in FIG. 3, to be corrected. The bimetal elements 6, 8 represented here in FIG. 4 also respectively have a layer structure, consisting of at least two element layers 10, 12, such as that which has already been explained at length with reference to FIG. 3.

(21) In FIGS. 5 to 7, the embodiment discussed above, according to FIGS. 1 to 3, is represented again in an isometric view (FIG. 5) and in a longitudinal section (FIG. 6). The embodiment of the bimetal controller 1 has been supplemented here by clamping devices 28, and in particular by two paternoster terminals 30, which allow easy connection of a conducting element 50 to the bimetal controller 1. If in the case of the prior art the contact elements 16, 18 have usually been connected to further conducting elements 50 by way of a soldered connection, here the connection of the bimetal controller 1 or of the contact elements 16, 18 takes place by way of the paternoster terminals 30. The advantage of this connecting technique is that no thermal energy is introduced into the contact elements 16 and 18, and by way of these into the switching contacts 17, 19, and in particular the switching contact 17 formed here as a beryllium-sprung spring, by a soldering or welding operation. This is so because it is specifically this introduction of heat that has led to deformations, and to a weakening of the restoring force of the switching contact 17 configured as a sprung-spring element, in the prior art. This artificial aging, which corresponded substantially to a thermal after-treatment, often led to a malfunction of the bimetal controllers 1.

(22) In principle, it should be noted that the use of this clamping technique by means of the paternoster terminals 30 for the connection of a conducting element to the contact elements 16, 18 is not restricted only to use in the case of the bimetal controller 1 according to the invention that is represented here. All components provided with contact elements or switching contacts, in particular with heat-sensitive contact elements or switching contacts, can be equipped correspondingly.

(23) The clamping devices 28 represented in FIGS. 5 to 7 for the electrically conducting connection of at least one conducting element 50 to at least one contact element 16, 18 of a switching device, and here of the bimetal controller 1, that is mounted in a housing 40 has the following:

(24) A clamping bolt 32 and a clamping bolt receptacle 34, which together define a clamping space 36, into which the conducting element 50 can be introduced, in particular from an outer side 43 of the housing 40, and into which the contact element (16, 18) protrudes, in particular from an inner side 45 of the housing 40 (see FIG. 7 in particular), the clamping bolt 32 being held in its axial direction, in particular in the housing 40, and lying with a clamping continuation 33 against the contact element 16, 18 in an unconstrained manner, and a counter bearing region 35 of the clamping bolt receptacle 34 being able to be moved toward the clamping continuation 33 and the contact element 16, 18 lying on it while reducing the clamping space 36 and able to be fixed at least in one clamping position such that the conducting element 50 and the contact element 16, 18 are fixed with respect to each other in an electrically conducting manner, without a flexural loading being introduced into the contact element 16, 18. The clamping device 28 according to the invention or the paternoster terminal 30 therefore has not only the advantage of easy connection of a conducting element to the contact elements 16, 18, in particular without any introduction of heat, but also the advantage of an unconstrained connection, so that no flexural loadings are introduced into the contact elements 16, 18 and the assigned switching contacts 17, 19.

(25) Preferably, the clamping bolt receptacle 34 is formed as a clamping bolt shoe, which at least partially encloses the clamping space 36, the counter bearing region 35 being formed on the inner bottom wall thereof, facing the clamping continuation 33. The clamping bolt receptacle 34 is in this case preferably mounted movably in the axial direction of the clamping bolt 32 on the clamping bolt. As represented here, the clamping bolt 32 is preferably provided with a threaded region, which is in threaded engagement with a thread receiving region of the clamping bolt receptacle 34 in such a way that the counter bearing region 35 of the clamping bolt receptacle 34 can be moved toward the contact element 16, 18 and away from it by a rotation of the clamping bolt 32 toward the clamping bolt continuation 33 and the contact element 16, 18 lying against it.

(26) As can be seen in FIGS. 5 and 6, the clamping bolt receptacle 34 is preferably formed from a metal strip 42 folded over a number of times. This allows inexpensive production, with at the same time good stability and sufficient material for the forming of a thread receiving region.

(27) The clamping bolt receptacle 34 preferably has on its lower bottom region a covering element 44, which serves during the connection of a conducting element as a guide for it. The covering element 44 in this case preferably extends axially parallel to the clamping bolt 32 in such a way that, when there is a reduction in the clamping space 36, that is to say brought about here by a rotation of the clamping bolt 32, it successively covers a receiving opening 48 in the housing 40. This prevents inappropriate introduction of the conducting element.