DE1590760A1 - Thermal switch - Google Patents

Description

HÖGER - LEGAL RIGHTS - GRIESSBACH - HAECKER PATENT LAWYERS IN STUTTGART

A 55 394 h

10/17/1966

O.S. Ser.No. 504.822

! Oexas Instruments Incorporated, Dallas, Sexas, U.S.A.

Thermal switch

The invention relates to thermal switches with a switch frame, which has a first and a second connecting member which can be connected to external electrical lines and which are electrically connected to one another at predetermined temperatures by an am Switch frame arranged thermal element can be connected or disconnected, which is electrically connected to the first connection element and interacts with the second connection member via a contact.

When designing and manufacturing snap action thermal switches or thermostats, it is necessary to To design each individual (thermostat for a specific temperature range. After the thermostat is assembled, 1st it is necessary to calibrate it so as to ensure that it operates within the desired range. The calibration the individual gate directions is not just a substantial one

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Associated loss of time, but also contributes to manufacturing costs of the switch. When the switch is assembled and not calibrated within the desired range can, the whole assembly must be thrown away «because that with Bimetallic connecting link usually working as a son-app effect is welded to a holder, in particular any cable of the switch housing. Ss would therefore be advantageous if at snap action thermostatic switches Calibration would not be necessary or the bimetallic elements in these cases can be easily exchanged in order to change the working range of the switch.

The invention is therefore based on the object of creating a thermal switch that does not need to be calibrated. This task is performed with the Ihermos switches mentioned at the beginning solved according to the invention in that the Theraoglied with the first connector only via an ohmic transition point connected is. This construction makes a firm connection of the Shermo link with a girder and therefore practical any significant change in the characteristics of the Ihermo member avoided *

Another advantage of the invention is that the! Dhe * - Moglieder easily and without changing a switch part can be removed and replaced if, for example, the response range of the switch is to be changed.

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The switch according to the invention is in the puncture reliable and can easily be produced «because he also consists of a minimum number of parts.

Furthermore, according to the invention, the thermostatic switch is compact and small and can eo within the protected area Facility to be built in that he was there against inflation Currents and protection against overheating

Further advantages and features of the invention emerge from the following description in connection with of the drawing containing embodiments of the invention. In the drawing show:

Fig.1 is a complete, exploded view of the Switch according to the invention to represent the

individual switch parts,

Fig.2 shows a cross section through the switch to the

explain the relative position of the various assembled parts *

3 shows a cross section along line 3-3 of Pig. 2, Pig. 4 shows a cross section along line 4-4 of FIG.

At the beginning it should be mentioned that the basic elements of the switch in Fig.l are pulled apart and see assembled in Pig.2. The switch has a housing with a

Base 3 nnä an upper part 2, both of which are, for example, made of a correspondingly shaped plastic; the also made of

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Bakelite can be formed. The thermal member, which can for example be a bimetal plate working with a snap action, is designated as a whole by 4 and has awei or more interconnected metallic layers which have different coefficients of expansion. The thermal link 4 establishes an electrical contact between the two connection elements which are arranged in the base and which will be discussed further below ο

The base 3 of the switch is shaped so that the various parts can be fitted. For example, a cuboid recess 18 is arranged on its inner surface in such a way that a prismatically shaped bearing part 10 of a first connecting member fits into this recess = at adjacent corners of the base 3 there is a. _; Cutout 15 czw, 16 are provided, which serve to accommodate outwardly protruding connecting pieces. Furthermore, a stop pin 17 is provided in the base, which limits the downward movement of the thermal link 4. At each corner of the base there is a hole 14 which is aligned with the corresponding holes in the upper part 2 in order to enable the upper part to be fastened to the base by means of screws or rivets.

^:::: .i as SEnzes irit 2

.nzes ir.it 2 designated first connection element

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has many functions besides the connection function and has a connection strip which extends outward through the cutout 16 of the base 3 in order to form a connection to the switch. 9a and 9b to ^ the Ms reach the bearing piece 10 and are in electrical connection with it, in such a way that the conductor pieces 9, 9a and 9h result in a resistance line, which can be used seleiaent as a resistor. ,

The bearing piece 10 that fits into the recess 18 of the base results in a remote connection to the 2hermoglied 4. The other connection sum thermal member is formed by the connection strip 11, the contact piece 12 and the carrier plate 13, the together form the second connecting gliad * The carrier plate 13 fits into the right side of the base in lig.l where the connection strip 11 extends through the cross section 15 and out of this. The contact piece 12 is fastened on the carrier plate 13 and interacts with a contact of the thermal link 4.

The thermal member 4 has three parts .nämlich _y: a bimetal plate 4a, a cylinder pin 6 and a contact 5, the Birastallplatte is usually associated with one of the AnsciUussglieder within the switch read. in the

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In contrast to this, a kind of articulated connection is provided in the present invention the cylindrical pin 6 arranged on the thermal link 4 into the bearing piece 10 of the connecting link 7. The bearing piece 10 and the cylinder pin δ are designed so that the cylinder pin 6 fits into the bearing piece and is freely rotatable there, so that the thermo-member 4 can pivot and when heated can perform a free movement. When the switch is in the closed position and the temperature of the surroundings If the switch does not exceed a certain height required for actuation of the thermal element, the cylinder is at rest pin β in the bearing piece 10, and the contact 5 is electrically connected to the contact piece 12.

The upper part 2 shown in Fig.l and 2 fits over the Ansohluse devices and the Theraoglied. According to Fig. 2 the upper part 2 has a step 19 on the inside, which presses down on the thermal element 4 and thus holds the cylinder pin S in the bearing piece: 10, while the bearing piece 10 is like this is bent up so that it et ^ aa over the connecting strip 8 protrudes. In this way, an upward spring force is exerted against the thermal member 4. Since dia level 19 after pushes down »the cylinder pin is in good electrical contact with the bearing piece 10. However, since the cylinder pin β rotatable in the bearing piece IO in the manner of a hinge

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is, bo results in the step 19 down upward force exerted by the bearing piece 10 no hindrance to the desired movement of the thermal link 4 «

Pig. 3 and 4 show sections through the cylinder pin 6 and contact 5 »to determine the position of certain parts when the switch is closed. 3 explains the engagement of the bearing piece 10 into the recess 18 and FIG. 4 the mounting of the carrier plate 13 through the upper part 2, the contact piece 12 is arranged so that it cooperates with the contact 5 when the switch is in the closed position.

The operation of the switch depends on the characteristics of the thermal link 4, which is made from a plate is that has two or more metal layers with different expansion coefficients, so that the change

temperature causes uneven expansion or contraction of adjacent layers. The plate is so shaped that they have a cup-like or non-developable section

has that protrudes from an end face of the plate. By doing The illustrated embodiment has the lower metal layer M1 has a higher expansion coefficient than that upper? <~ etaHse sees M2. If the Tnarmoglieö. 4 shaped like this and kci: t "is trued, ao arises when the! temperature is increased

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the uneven expansion of the metals creates a tension that flattens the curvature until at a predetermined temperature, a sudden bulging of the non-developable part in the opposite Direction occurs, i.e. a reversal of the P © rm, the eo is maintained for a long time until the temperature has decreased significantly * borrowed. When a predetermined, much lower temperature is reached afterwards, this is reversed Thers-O link suddenly returns to its original form. Both movements for reversing the curve are extraordinarily sudden and rapid and become during the expansion and contraction of the metal layers M1 and M2 that make up the thermal link "

The rapid interruption of the thermal link 4 can be used to open or close electrical circuits. If, for example, the current path from connection strips 8 via the conductor pieces 9, 9a and 9b _f , the bearing piece 10, the cylinder pin 6, the thermal element 4 and its contact 5, the contact piece 12, the carrier plate 13 to the connection strip 11 is closed, so can voltage can be applied to an electrical circuit using the switch. As long as the thermal element 4 is closed, the contacts 5 and 12 are in contact, so that current flows through the switch in any direction. However, if the

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Temperature of the area around the switch above a certain If the point rises, the thermal link 4 reverses its curve shape, so that the contact 5 separates from the contact piece 12 and the switch is opened. When the thermal link 4 reverses its curve shape, it hits the stop pin 17, which helps to keep the contact 5 from the contact piece 12 at a distance. Due to the free rotation of the cylinder pin 6, the thermal link 4 can move the contact upwards.

The current flowing through the conductor pieces 9, 9a and 9b heats this area within the envelope and supports it thereby a temperature increase of the thermal link 4 to above the ümschnappunktes. In this way, the Switches can be made responsive not only to electricity but also to heat. The heat also serves to to extend the shutdown time, so that "a motor or another facility in which the switch is installed cools down sufficiently - as a considerable between the temperature in the device and on the thermal link 4 *

An important feature of the invention is the rotatable interaction of the cylinder pin 6 with the bearing piece 10 ₀

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Duron's use of such a compound will die time consuming and expensive calibration of the switch eliminated. The reason for this is as follows: every single bimetallic thermocouple, for example the thermocouple 4 »has a so-called free overhead temperature. this is the Temperature at which the thermocouple changes from a form to the other changes and returns from this again if the plate is not attached to any other structural part is. When normally bimetallic plates are welded to a »frame or another part of a switch or are otherwise fastened, the temperature at which the sudden change in curve occurs is changed as a result of the connection of a part of the plate with a rigid holder. In the present invention, however, that is bimetallic thermal element 4 in its movement and rotation in the bearing piece 10 free, so that the free snap-on temperature remains essentially unchanged. The free ümschnapping temperature of the thermal link 4 with its contact 5, the can slide freely on the surface of the contact piece 12, the other end being rotatably mounted on the cylinder pin 6 is essentially the temperature at which the switch actually operates. Any bimetal plate be used in the Sohalter, which has the desired working characteristics. The bimetal plate can then be exchanged if the working range of the switch is changed

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«Should be grounded. So the calibration essentially consists in that a bimetallic plate with a free temperature is used in the housing that of the one corresponds to the desired working range of the switch

Since the bimetal plate is not in its position by so-whitening is held, the switch can be assembled in a simple manner, with prefabricated parts only in one Housing must be installed, which is then sealed.

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Claims (16)

17 * 10.1966 patent claims 1. Thermostatic switch with a Schaltergeeteil, dae a first and a second "to external electrical leads connectable connecting member which are connectable to or separable at predetermined temperatures electrically to each other by a valve disposed at Sohaltergeetell thermal member nit the first terminal member is electrically connected 'and a contact interacts with the second connection element, characterized in that the xhermo element (4) bit is connected to the first connection element (7) only via an ohmic transition point (6, 10). 2. Thermal switch according to claim 1, characterized in that the Xhermo member (4) is housed in a preferably two-part housing which has a base (3) and an upper part (2). 3. Thermal switch according to claim 1 or 2, characterized in that the ohm * see transition point as a pivot connection (6, 10) is trained. 4 · Thermal switch according to one of the preceding claims, characterized characterized in that the ohmic transition point is designed in the manner of a joint (6, 10) 5. Thermal switch according to one of the preceding claims, characterized characterized in that the first connecting member (7) has a bearing piece (10) in the manner of a bearing shell into which an am Thermal member (4) arranged rotary piece (6) engages - 13 - . 009825/1604 A 35 394 h - 13 - ¹⁵⁹⁰ ^ O 6. Thermal switch according to claim 5 »characterized in that the bearing piece (10) has a prismatic recess. 7. Thermal switch according to claim 5 or 6, characterized in that the rotating piece is designed as a cylindrical pin (6). 8. Thermal switch according to one of claims 5 - 7 »characterized in that that the first connecting member (7) has a connecting strip (8), from the plane of which the bearing piece (10) is bent out upwards and thus acts resiliently on the rotating piece (6). 9. Thermal switch according to claim 8, characterized in that between the connecting strip (8) and the bearing piece (10) Heating element (9, 9a, 9b) is arranged. 10. Thermal switch according to claim 9 »characterized in that the heating element has a number of conductor pieces (9, 9a, 9b) which are arranged around the bearing piece (10) and are preferably integral with the connecting strip (8). 11. Thermal switch according to one of claims 5 - 10, characterized in that the Ihermo member (4) at one end Three-piece (6) and at the other end a contact (5) carries. 12 «thermal switch according to one of the preceding claims, characterized characterized in that the base (3) has recesses (15-16, 18) for receiving at least cables of the connecting links (7; 11 »12, 13), for example the bearing piece a (10) * - 14 - 009825/1604 10/17/1966 13 · Thermal switch according to one of the preceding claims, characterized in that the two housing parts (2, 3) so interlock that the connecting members (7; 11, 12, 13) and / or the Thenaoglied (4) through corresponding inner surfaces the housing parts (2, 3) are held. 14.! Thermal switch according to one of the preceding claims, characterized characterized in that the upper part (2) has a curved recess and a collar fitting into the base. 15. Thermal switch according to one of claims 5-14, characterized in that that the upper housing part (2) has a step (19) which on the Shermo member (4) about & fähr compared to the Rotary piece (6) presses. 16. Thermal switch according to one of the preceding claims, characterized characterized in that the second connection member has a carrier plate (13) which has a connection strip (11) and a Contact piece (12) carries. 17 · Thermal switch according to one of the preceding claims, characterized characterized in that the thermal member is a bimetallic snap plate (4). 009825/1604 Blank page