CN201364863Y - Thermal overload protection device and bimetal trigger device assembly - Google Patents

Abstract

The utility model relates to a thermal overload protection device with a bimetal trigger device assembly fixed in a housing (40). The bimetallic trigger device assembly (1) comprises a base plate (10), on which is provided: a clamping arm (12) with a connecting piece (14) receiving a clamping terminal (16); the bimetallic arm (22) of the bimetallic fixing piece of the metal piece (20); and a fixed end with a fixing piece (32) for fixing said bimetallic trigger assembly (1) in the housing (40) (30).

Description

Thermal overload protection device and bimetal trigger device assembly

technical field

The utility model relates to a thermal overload protection device according to the preamble of claim 1 with a bimetallic trigger assembly fixed in the casing.

The utility model further relates to a bimetallic trigger device assembly for a thermal overload protection device according to claim 3 .

Background technique

A thermal overload protection device of this type is known, for example, from EP 0828 276 A2. Such a thermal overload protection device has a conductive conductor fixed in the casing to form a bimetallic trigger device, which is placed in the casing in the form of a clamping device. The bimetal triggering device is arranged directly on the conductor in the form of a bimetal strip. Further, a clamping terminal can also be arranged on the conductor, which is in the form of a flat plate with a threaded hole, and a clamping bolt can be screwed into the threaded hole. The screwing direction of the bolt is perpendicular to the longitudinal extension direction of the bimetallic strip. Although the conductors are held in the housing by the lugs, tightening of the clamping bolts results in a conductor load in the form of an additional tightening force rectangle, which acts on the bimetal, causing it to twist from its set position . As a result, triggering accuracy is reduced.

In order to avoid such problems, it can be proposed to realize the clamping terminal and the bimetallic clamping part as separate components connected by a movable conductor strand. This makes the position of the bimetal no longer affected by the clamping terminals, but the installation of the device is thus more complicated, since three components have to be inserted and connected to each other.

Utility model content

The purpose of this utility model is to provide a kind of this kind of thermal overload protection device, its clamp terminal and bimetal clamping part are integrated into an integrated and pre-assembled component, and can avoid the bimetal from being affected by the bolt. Influence of additional tightening torque.

This object is achieved with the thermal overload protection device according to the invention by the characterizing part of claim 1 and with the bimetal trigger assembly by the characterizing part of claim 3 .

The utility model is characterized in that the bimetallic trigger device assembly includes a substrate, on which there are: a clamping arm with a connecting piece that accepts the clamping terminal; a metal arm; and a fixed end with a tab securing the bimetallic trigger assembly within the housing.

An advantageous effect of such a switching device according to the invention, which is constructed according to the invention, is that, by means of the connecting piece and the bimetal fixing piece provided according to the invention, the bimetal body is isolated from the relative rotational torque of the clamping terminal Open, this rotational torque is applied to the clamping terminal by the clamping bolt when the clamping bolt is tightened. A tightening torque applied to the clamping terminal is first absorbed by the connection lug, so that the base plate is thus not affected. A small part of the tightening torque is also transferred to the base plate, where it is absorbed by the bimetallic retainer between the base plate and the bimetal arm. In addition, the substrate is also held in the housing by the fixed end and the fixed piece.

Generally speaking, the rotational torque applied by the clamping bolt to the clamping terminal will be absorbed by the housing through the clamping portion. In the case of a particularly strong rotational moment, the clamping portion of the fixed piece in the housing cannot be fully absorbed, and even when the rotational moment is so strong that the shell deforms at the clamping portion of the fixed piece, the first bimetallic fixed piece The triple protection zone acts to absorb this additional tightening torque, thus preventing twisting of the bimetal arm itself.

This prevents the transfer of the tightening torque to the bimetallic arm itself due to the particularly strong rotational torque that occurs when the clamping bolt is tightened, and also enables simple assembly, since only one component is required, the pre-assembled clamp Holding terminals and bimetal strips can be installed into the housing at a certain step in the installation process.

Further advantageous refinements and improvements of the invention are set forth in the dependent claims.

Description of drawings

Embodiments of the utility model are shown in the drawings, and the utility model as well as further advantageous designs and improvements as well as other advantages of the utility model will be introduced and described. in:

Figures 1a-d respectively show a side view, a top view, a bottom view and an end view of a bimetallic trigger assembly according to the present invention;

Fig. 2 schematically shows an internal view of a three-phase thermal overload protection device according to the present invention, wherein a bimetallic trigger device assembly according to the present invention as shown in Fig. 1 is inserted for each phase .

Detailed ways

FIG. 2 shows an internal view from above into the thermoplastic housing 40 of the opened thermal overload protection device. The protection device is divided into three heat capacity chambers 42 , 44 , 46 by two partitions 50 . Within each heat capacity chamber is located a bimetal trigger assembly 1, which is shown and described in more detail with respect to Figures 1a-d. This thermal overload protection device as shown in Figure 2 is a three-phase thermal overload protection device in the form of a base, where the cover of the base is removed so that an internal view into the open base of the base can be obtained.

The end surface of each heat capacity chamber is provided with a clamping terminal, and this terminal connects a connecting conductor for one phase of each heat capacity chamber from the outside of the housing.

The free end of each bimetallic strip cooperates with a slider 60 on the other end face opposite this terminal. Slider 60 transmits the thermally induced bending of one or more bimetallic strips to a snap switch (not shown), whereby the strong thermally induced bending of the bimetallic strips causes one or more The auxiliary current path is switched off or on. Both the snap-action switch and the auxiliary contacts are located in the space viewed by the observer towards the machine above the plane shown in FIG. 2 . An auxiliary contact-clamping terminal is also provided here. The slider 60 is a one-piece assembly that passes through the bulkheads 48,50.

The minimum triggering threshold of each bimetal triggering device assembly is set in such a way that switching takes place immediately at the moment when a defined, predeterminable critical deflection of the thermal bimetal strip is exceeded. This critical bending corresponds to the time when an overcurrent occurs in at least one of the three phases, this current has occurred for an extended period of time and is directly greater than the nominal current which the overload protection device is set to monitor. The setting of the minimum triggering threshold of each thermal bimetallic triggering device assembly can be realized by adjusting the position of the bimetallic sheet relative to the slider 60 . Like this, in order to realize the reliability and function reproducibility of the thermal overload protection device, it is required to adjust the position of the bimetal sheet relative to the slider 60 at one time and then do not change it, especially do not cause the change by connecting the conductor to the clamping terminal. In order to ensure this, the bimetallic trigger assembly 1 may for example be assembled as shown in Figs. 1a-d.

Each bimetallic trigger assembly 1 has a base plate 10 as a central part, which is in the form of a rectangular metal plate. First, a fixed end 30 is formed on its long side, its length is basically half of the length of the base plate, and it is also in the shape of a rectangle. The fixed end is supported by a fixed piece 32, which is in the form of a metal piece directed to the lower side of the base plate. By means of the fixing piece 32 , the base plate 10 and thus the bimetallic trigger assembly 1 can be connected and fixed at the recesses 52 , 54 , 56 of the housing through clamping terminals. Housing recesses 56, 54 are provided on the partitions 48, 50, and housing recesses 52 are provided on the inner side of the housing outer wall. The housing recess is adapted to be cast together with the other housing parts in the injection molding process during housing production.

An upper clamping arm 12 and a lower bimetallic arm 22 are formed on the long side of the substrate 10 opposite to the fixed end 30 . Both arms are shaped in the shape of curved handles, both bent at 90 degrees, thereby each comprising a free end 13 , 23 protruding substantially perpendicular to the plane of the base plate 10 .

A connecting piece 14 is perpendicular to the free end 13 of the clamping arm and protrudes parallel to the long side of the base plate 10, and a clamping terminal 16 is arranged at its free end in the form of a screw hole plate. The broad side of the screw hole plate constituting this clamping terminal 16 is parallel to the end side of the base plate 10 . It has a threaded hole 17 approximately in the middle, into which a clamping screw can be screwed, whereby a conductor not shown in the figure can be screwed into the clamping terminal 16 .

A bimetal fixing piece 32 (32 in the original text, should be 24 actually) is perpendicular to the bimetal end 23 and extends parallel to the long side of the base plate 10, on which the bimetal strip 20 is fixed. The bimetal strips extend with their long sides parallel to the plane of the substrate 10 and substantially parallel to the broad sides of the substrate. The bimetallic strip 20 is wound around a current conductor 21, the heat generated by its current causing the bimetallic strip to heat and thereby bend in a direction perpendicular to its long and wide sides at the same time.

The clamping arm 12 and the bimetallic arm 22 are perpendicular to the longitudinal extension direction of the bimetal strip 20 , and the broad side of the substrate 10 is parallel to the longitudinal extension direction of the bimetal strip 20 . The connecting piece (14) and the bimetallic fixing piece (24) are perpendicular to a plane positioned by the longitudinal extension of the bimetal (20) and the longitudinal extension of the clamping arm (12) or bimetal arm (22).

A clamping bolt is screwed into the screw hole opening 17 in a direction perpendicular to the longitudinal extension of the bimetallic strip 20 . When this bolt is screwed into the clamping terminal 16 very tightly, the bolt tightening torque will be transferred to the screw hole plate supporting the clamping terminal 16 and try to make it rotate in the same direction. The additional tightening torque transmitted to the screw hole plate 16 will cause a rotation of the screw hole plate about the axis of the connecting piece. The connecting piece also rotates around itself and absorbs the rotational moment of the screw plate. In this way no rotational torque is transmitted to the base plate 10 . The base plate maintains its position, which is determined by the clamping portion of the base plate on the housing wall or on a partition.

However, some slight residual rotational moments are transmitted to the base plate 10 , which cause the base plate to rotate relative to the housing in its housing recess, so that the position of the bimetallic strip 20 is not affected. This is because the residual rotational moment of the substrate 10 will only cause the bimetallic fixing piece 24 to rotate a little. This completely absorbs the residual rotational torque and does not transmit additional tightening torque to the bimetallic strip 20, so that the bimetallic strip remains in its set position independent of the tightening force of the clamping bolts.

When this part includes the base plate (10), the clamping arm (12) with the connecting piece (14) receiving the clamping terminal (16), the bimetallic arm (22) with the bimetallic fixing piece (24), It is advantageous to produce the fixing end ( 30 ) as well as the fixing piece ( 32 ) as a one-piece Stanz-bent part made of metal such as brass or copper. On this component the bimetallic strip 20 can then be mounted, for example welded or soldered. The entire bimetallic trigger assembly 1 can be used as a pre-installed assembly, and can be installed into the casing 40 in a certain step of the installation process.

List of reference signs

1 bimetallic trigger assembly

10 Substrate

12 clamping arm

13 Free end of clamping arm

14 connecting pieces

16 clamp terminal

17 threaded hole

20 bimetal strips

21 conductors

22 bimetal arm

23 bimetallic free end

24 Bi-metal fixed piece

30 fixed end

32 fixed piece

40 shell

42 heat capacity chamber

44 heat capacity chamber

46 heat capacity chamber

48 Partition

50 partitions

52 shell recessed

54 shell recessed

56 shell recessed

60 sliders

Claims (7)

1. A thermal overload protection device, said thermal overload protection device has a bimetal trigger device assembly fixed in the housing (40), characterized in that said bimetal trigger device assembly (1) comprises a substrate (10), the base plate is provided with: a clamping arm (12) with a connecting piece (14) receiving a clamping terminal (16); a bimetal fixed piece with a bimetallic piece (20) a bimetallic arm (22); and a fixed end (30) with a fixing piece (32) fixing said bimetallic trigger assembly (1) in said casing (40). 2. The thermal overload protection device according to claim 1, characterized in that: the fixing piece (32) is inserted into a housing recess ( 52, 54, 56). 3. A bimetallic trigger assembly for a thermal overload protection device, characterized in that: the bimetallic trigger assembly (1) includes a substrate (10), on which is provided: The clamping arm (12) of the link piece (14) of (16); Have the bimetallic arm (22) of the bimetallic fixed piece that accepts bimetallic strip (20); The assembly (1) is fixed to the fixed end (30) of the fixed piece (32) inside the housing (40). 4. The bimetallic trigger assembly according to claim 3, characterized in that: the wide side of the base plate is parallel to the longitudinal extension direction of the bimetallic strip (20). 5. The bimetal trigger assembly according to claim 4, characterized in that the clamping arm (12) and the bimetal arm (22) are perpendicular to the longitudinal extension direction of the bimetal strip (20). 6. The bimetal trigger assembly according to claim 5, characterized in that: the connecting piece (14) and the bimetal fixing piece (24) are perpendicular to the longitudinal extension of the bimetal piece (20) direction and the plane on which the clamping arm (12) or the bimetallic arm (22) is positioned and stretched. 7. The bimetallic trigger device assembly according to claim 3, characterized in that: some units include a base plate (10), a clamping arm (12) with a connecting piece (14) receiving the clamping terminal (16) , a bimetallic arm (22) with a bimetallic fixing piece (24), a fixed end (30) and a fixing piece (32), and the fixing piece is made into an integrally formed punching and bending part.

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