JPH10294048A - Inexpensive temperature switch and its calibration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature electric switch which reduces the number of part items, is suitable to high volume production, and is low in production costs, and provide a calibration method for the temperature electric switch. SOLUTION: A motion transmitting pin member 28 is mounted to a movable contact arm such that it can be adjusted, and is extended downward toward a temperature sensing snap disc 30 accepted by a disc sheet 20b formed over the bottom wall 20a of a housing. The disc 30 transmits the movement to the movable contact arm by way of the motion transmitting pin member, and an electrical engagement with a static contact 26 is thereby released. In a deformation type temperature switch, a spring is mounted to the inside of the housing 20, and it is located over the disc sheet 20b regardless the attitude of the switch. Calibration is performed by letting a gap between a motion transmitting pin and a reference level be adjusted so as to be less than a selected quantity, and continuously deforming the side wall of the housing until a movable contact is moved so as to be released from the electrical engagement with the static contact 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a thermoelectric switch, and more particularly, to a thermoelectric switch using a snap-actuated temperature-sensitive disk for controlling the energization state of an electric circuit.

[0002]

2. Description of the Related Art Conventional temperature switches generally use an electrically insulating base of plastic or a ceramic that withstands high temperature environments to mount the components with the required electrical insulation between the switch components. The base is mounted on a thermally conductive metal container such that the temperature sensitive disk conducts heat to a heat source to be monitored. Although this structure is effective, it is still cheaper to manufacture,
There is a need to provide a device that is easy and accurate to calibrate.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermoelectric switch having a lower manufacturing cost than the above-mentioned conventional temperature switch. The other purpose is
An object of the present invention is to provide a temperature electric switch which has a smaller number of components than the conventional temperature switch described above and is particularly suitable for mass production. Yet another object is to provide a method for calibrating this new inexpensive temperature electrical switch.

[0004]

SUMMARY OF THE INVENTION Briefly, in the present invention, first and second ladle-type terminal members are formed from metal strips and have opposing side walls, end walls, respectively.
It has a bottom wall. The terminal member has a flange received on a shelf formed on a pair of opposing side walls of the temperature sensitive disk receiving housing, and a strip of electrically insulating material is disposed between the terminal member and the housing. The distal end of the side wall, via an electrically insulating strip,
It is bent to clamp over the flange.
The terminal members have their open ends opposed to each other at a distance, the fixed end of the movable contact arm is cantilevered on the bottom wall of one terminal member, and the free end of the movable contact arm is connected to the bottom wall of the other terminal member. It is biased to engage the upper stationary contact. Tabs are provided on the flanges of the terminal members and bent to clamp over the electrically insulating strips, separating the terminal members from each other by a predetermined distance. A temperature-sensitive snap mounted in a motion transmitting member in the form of a ceramic pin is adjustably mounted in an opening formed in the movable contact arm and mounted below the arm on a disk sheet formed in the bottom wall of the disk receiving housing. Extends to the disk. The disc is movable between oppositely recessed configurations, depending on the temperature conditions selected, and in one of the recessed configurations, the movable contact arm is brought into electrical engagement with the stationary electrical contact. Deviate to cancel.

[0005] In an alternative embodiment, a spring is mounted on the disk receiving housing and engages the outer periphery of the snap disk to bias the disk toward the disk sheet, thereby irrespective of the position of the temperature switch. A consistent reaction to heat occurs.

In the method of calibrating a temperature switch according to the present invention, first, the position of the motion transmitting pin is set between 0 mm and 0 mm between the pin and the plane separated from the disk sheet by an amount equal to the thickness of the disk. Adjust so that there is a gap of 0.2 mm. A spring loaded member carried by the punch was moved vertically from a position below the temperature switch to engage a bottom surface of the housing aligned with the disk sheet and mounted against the spring loaded member. Pins lift the disk from the disk sheet through openings in the bottom wall of the housing. The punch is moved further in the same direction, engaging the intermediate wall of the housing and continuing the movement to deform the side wall of the housing. Preferably, the side wall is weakened by providing one or more slots at selected locations and furthermore, the wall is slightly buckled in a predetermined direction, i.e., inward. Preferably, it is pre-bent by an amount, for example, 0.25 mm. The movement of the punch is terminated as soon as the movable contact arm is disengaged from the stationary contact.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, advantages and details of the novel and improved thermoelectric switch of the present invention and its calibration method will become apparent from the following detailed description of the preferred embodiment of the present invention. Would. 1-6, a temperature switch 10 according to the present invention has a switch portion and a temperature sensitive portion, the switch portion being made of a suitable conductive metal such as nickel-plated steel and having a generally ladle-shaped first, There are second terminal members 12, 14, each terminal member having a bottom wall 12a, 14a, an end wall 12b, 14b, and first and second side walls 12c, 12d and 14c extending upward from the bottom wall.
14d and flanges 12e, 14e extending laterally outwardly from the top of the upwardly extending wall. Terminal portions 12f and 14f extend laterally outward from the flanges of the end walls 12b and 14b. The terminal forms the strip into a punching ladle shape, as shown at 14g in FIG.
Preferably, the strip is bent over itself to thicken the terminal.

[0008] A strip 16 of a suitable electrically insulating material, such as NOMEX, a trademark of the Aramide paper of Dupont de Nemours, is provided on the terminal portion 1.
Wound around 2,14. Terminal 12
A pair of tabs 12h, 14h extending from flanges 12e, 14e adjacent to f, 14f are folded to clamp strip 16. Tab 12h to Tab 14
The width of the strip 16, measured in the direction of h, is selected so that the terminals 12, 14 are separated from each other by a predetermined distance 18, shown in FIG. Centrally located opening 16
a is formed in the strip 16 and passes through a motion transmitting member described later.

The temperature sensitive portion has a heat conducting disk receiving housing 20 made of a suitable metal such as nickel plated steel used for terminals 12 and 14, the housing 20 comprising an annular disk receiving sheet 20b, It has a bottom wall provided with a cylindrical wall portion 20c extending upward therefrom and extending to a laterally extending intermediate wall 20d (FIG. 6). Opposing first and second side walls 20e extend upward from the intermediate wall 20d to a shelf 20f extending laterally outward. Terminal 1
Each of the flanges 12e, 14e of the two, 14, together with the insulating strip 16, is received on a shelf 20f of the housing 20, and the distal free end 20g of the side wall 20e is connected to the flange 1
2 e and 14 e are bent so as to be clamped through the insulating strip 16.

A movable contact arm 22 made of a suitable conductive material having good spring characteristics, such as beryllium copper, is welded to the bottom wall 14a at, for example, 22a and is cantilevered. It has a movable electrical contact 24 attached to both free ends. An opening 22b is formed through the arm 22 at a substantially central position between the fixed end and the free end, and the opening 22b is formed with a skirt 22c that frictionally engages with a ceramic pin 28 serving as a motion transmitting member. . The pin 28 is preferably a cylindrical member and is placed in the skirt 22c and held in frictional engagement with the skirt, but using a greater force than the pin experiences when using the temperature switch to achieve the desired longitudinal length. Can be adjusted to the directional position. A pin 28 mounted in the opening 22b extends downwardly toward the bottom wall 20a of the disk receiving housing 22 and is located adjacent to a disk mounted on a sheet 22b in the bottom wall 20a, as described below. . The two walls 22d of the arm 22 shown in FIG. 4 or the deformed side surfaces 22 'shown in FIG. 5 are bent out of the plane of the arm to make the arm stiff at a portion other than the flexible portion adjacent to the cantilevered support end. . Arm 2
2 is movable toward and away from a stationary electrical contact 26 fixed to the bottom wall 12a of the terminal member 12, and is pre-biased toward the stationary contact 26.

Snap disk 30 for temperature sensitive switch
Is the annular disc sheet 20b of the heat conducting housing 20
And at a predetermined temperature, moves between an upwardly concave configuration as shown in FIGS. 3 and 5 and an upwardly convex configuration (not shown). I have.

In operation, temperature switch 10 is in heat transfer relationship with the heat source being monitored. At temperatures below a predetermined level, the contacts 24, 26 engage each other, forming an electrical circuit between the terminals 12 and 14. When the temperature of the heat source rises and the temperature of the snap actuation disc 30 rises to a predetermined level, the disc 30 snaps from the illustrated configuration to the oppositely recessed configuration and moves through the motion transmitting member 28. Movable contact arm 2
2, 22 'to disengage the contacts and interrupt the flow of current between the terminals. The design of the temperature switch 10 is made suitable for mass production technology. Terminal 12,
14, the housing 20, the insulating strip 16, and the movable contact arms 22, 22 'can be automatically formed and assembled from reel wound strips, thus:
Provide a low cost temperature switch.

An alternative embodiment of the temperature switch is shown in FIGS. 7 and 8 in which a spring member 32 is mounted in the disc receiving housing 20 and the snap actuated disc 3
0 is maintained on the disk sheet 20b regardless of the attitude of the temperature switch 10 '. A spring member 32, made of a suitable material having good spring characteristics, generally has an annular base 32a that is aligned with the disk sheet 20b and preferably has a slightly smaller outer diameter, and a pair of upwardly extending spring arms 32b. doing. The spring member 32 is placed on the disc 30 with the distal free end 32c of the spring arm 32b engaging the bottom surface of the insulating strip 16;
A force is applied to the outer periphery of the disk 30, and the temperature switch 10 '
The disc is pressed so as to engage with the disc sheet 20b even when the disc is in an upside down or oblique posture. As a result, the response to temperature is more reliable. The rest of the switch is the same as the embodiment of FIGS. 1 to 6 except that the side wall 22d "of the movable contact arm 22" is modified to extend downward, and need not be described. .

Regarding the calibration, reference is made to FIGS. 5, 9a to 9d. First, the position of the motion transmitting member 28 in the opening 22b with respect to the disc sheet 20b is determined by the member 2
8, the clearance C _d ie calibration distance between the calibration level corresponding to C _c ie flat disc (Fig. 5, FIG. 9
a) In other words, the member 28 and the disc sheet 20
The length determined by adding the thickness of the disk to the distance between the plane where b is located is about 0 to 0.2 mm. The tool in the form of a punch 40 is provided with a first outer member 4 which is movable in the front-rear linear direction, ie, up and down in FIGS.
0a. The outer member 40a has a first top surface 40b configured to match the intermediate wall 20d of the housing 20, and defines a cylindrical cavity 40c. The second cylindrical inner member 40d is received in the cavity 40c and is movable in the same linear direction. The second member 40d is provided with a radially extending flange 40e that engages a stop surface 40f formed on the first member 40a to limit outward movement of the second member 40d. The second member 40d is biased toward the stop surface 40f by a compression spring 40g acting on the base 40h of the punch. A pin 40k is centrally located and fixed in the second member 40d and has a longitudinal axis extending in a direction parallel to the linear direction of the punch movement. The top 40m of the pin 40k is accurately located with respect to the raised annular surface 40n of the second member for the following purpose. The annular surface 40n is configured to engage with an annular portion on the bottom surface of the housing 20 aligned with the disk sheet 20b.

As shown in FIG. 9b, an annular surface 40n is formed on the annular portion of the bottom wall 20a aligned with the disk sheet 20b.
Contacting the reference level C _R, the pin 40k is the bottom wall 20
a is through receiving opening 20h of the temperature switch to lift the center of the disc 30 to the calibration level C _C 1
It is raised relatively to zero. At this stage, the surface 40b of the first tool member is not yet engaged with the housing 20, and the contacts 24, 26 are engaged with each other. In the next step, FIG. 9 c, the surface 40 b of the first outer member 40 a
It engages with the housing 20 at d. 9d, the punch 40 deforms the side wall of the housing 20 until the disk 30 engages the motion transmitting pin 28,
The contacts 24, 26 are separated to disengage electrical engagement, completing the calibration procedure. The distance between the motion transmitting member 28 and the reference level C _R , which is the level at which the surface 40b engages the can 20, depends on the thickness of the material of the housing 20, the thickness of the disc 30, and the calibration distance C _d And the amount of springback.

To facilitate this procedure, the side wall 20e is weakened during the calibration procedure such that the side wall 20e undergoes controlled buckling in place, for example, by forming laterally extending slots. It is preferable to keep it. Furthermore, the side walls may be pre-bent by a small amount, ie 0.25 mm, as shown by the dashed line 20m in FIG. 5, to guide the buckling or bending movement inward. The temperature switch according to the present invention does not use a conventional ceramic or plastic housing member by using a stamp housing and an insulating material, thereby providing an inexpensive device. While the embodiments of the present invention have been described with reference to the accompanying drawings, it should be understood that modifications and equivalents of the above-described embodiments included in the appended claims are included in the present invention.

[Brief description of the drawings]

FIG. 1 is a top plan view of a temperature switch of the present invention.

FIG. 2 is a right side view of the switch in FIG. 1;

FIG. 3 is a sectional view taken along lines 3-3 in FIG. 1;

FIG. 4 is a sectional view taken along lines 4-4 in FIG. 3;

FIG. 5 is a sectional view taken along lines 5-5 in FIG. 3;

FIG. 6 is a plan view of the switch bottom of FIG. 1;

FIG. 7 is a sectional view similar to FIG. 5 of a variation of the temperature switch of FIGS. 1 to 6;

FIG. 8 is a sectional view taken along lines 8-8 in FIG. 7;

FIG. 9a is a cross-sectional view of a portion of a tool and a temperature switch;
3 shows one of the stages of switch calibration of the present invention.

FIG. 9b is a sectional view of a part of the tool and the temperature switch;
3 shows one of the stages of switch calibration of the present invention.

FIG. 9c is a cross-sectional view of a portion of the tool and temperature switch;
3 shows one of the stages of switch calibration of the present invention.

FIG. 9d is a sectional view of a part of the tool and the temperature switch;
3 shows one of the stages of switch calibration of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Temperature switch 12, 14 Terminal member 12a, 14a Bottom wall 12b, 14b End wall 12c, 12d 1st side wall 14c, 14d 2nd side wall 12e, 14e Flange 12f, 14f Terminal part 16 Insulation strip 16a Opening 20 Housing 20a Bottom wall 20b Annular disk receiving sheet 20c Cylindrical wall portion 20d Intermediate wall 20e Side wall 20f Shelf 22, 22 ', 22 "Movable contact arm 22c Skirt 24 Movable electrical contact 26 Static electrical contact 28 Pin (motion transmitting member) 30 Temperature sensitive snap disk 32 Spring Member 40 Punch 40a First outer member 40c Cavity 40d Second inner member 40g Spring 40k Pin

Claims (12)

[Claims] 1. A temperature switch comprising first and second conductive terminal members each having a terminal portion and a main body, wherein the main body comprises a bottom wall, an end wall,
A terminal having opposed first and second side walls extending upward from the bottom wall to a top of the end wall, and a flange extending laterally outward from the top of the end wall and the first and second side walls of the terminal member; A terminal member extending laterally outwardly from a flange at each end wall, a generally heat-dissipating disk receiving housing, a generally annular disk receiving sheet, and an upper side from the bottom wall on each side of the disk receiving sheet. A first side wall of the terminal member having opposed first and second side walls extending to the first and second shelves, wherein a flange of the first side wall of the terminal member is received in isolation on the first shelf portion and a second side wall of the terminal member. Flanges are separably received in the second shelf, a strip of electrically insulating material is inserted between each shelf and each flange, and the distal ends of the side walls of the first and second housing members are respectively , Hula And a tab extending from a flange in an end wall of the terminal member bent over the strip and the strip of electrically insulating material to engage the strip of electrically insulating material. A movable contact arm having a housing, a temperature sensitive disk placed on the disk receiving sheet and recessed in the opposite direction, and having a first and second opposed ends. One end is cantilevered on the bottom wall of one terminal member, and the other end is movable and disengaged to engage and disengage the bottom wall of the other terminal member. When the motion transmitting member extends from the movable contact arm to the temperature sensitive disk and the temperature sensitive disk is moved to one of the dished configurations, the temperature sensitive disk is displaced. But the temperature switch press having a movable contact arm, a to biasing so via the motion transfer member to transmit motion to the movable contact arm, thereby disengaging the movable arm from the other terminal member. 2. The temperature switch according to claim 1, wherein the movable contact arm has an opening therethrough between the first end and the second end, and the motion transmitting member opens the opening through the opening. A temperature switch characterized in that it is an electrically insulating pin frictionally engaged with a movable contact arm. 3. The temperature switch according to claim 2, wherein the opening has a skirt that depends from the opening and frictionally engages with the electrically insulating pin. 4. The temperature switch according to claim 2, wherein said electrically insulating pin is made of a ceramic material. 5. The temperature switch according to claim 1, wherein the strip of electrically insulating material is formed from NOMEX. 6. The temperature switch according to claim 1, wherein the bottom wall of the heat-conducting disk receiving housing member is an end wall of a cylindrical portion extending a predetermined distance upward to a position where the side wall is formed. A temperature switch, wherein a weakened portion is formed so that a side wall is deformed at a predetermined position during calibration. 7. The temperature switch according to claim 6, wherein said weakened portion is formed by at least one slot in each side wall. 8. The temperature switch according to claim 1, wherein an opening is formed in a bottom wall of the heat-conducting disk receiving housing member to facilitate calibration of the temperature switch. 9. The temperature switch of claim 1, further comprising a spring member mounted within the heat conductive housing member for applying a force to the heat conductive disk toward the disk receiving sheet. A temperature switch, characterized in that: 10. A temperature switch, comprising first and second conductive terminal members each having a terminal portion and a main body, wherein the main body comprises a bottom wall, an end wall,
A terminal member having opposed first and second side walls extending upward from the bottom wall to a top of the end wall, and a flange extending laterally outward from the top of the end wall and the first and second side walls of the terminal member. A generally annular disk receiving sheet, and opposing first and second side walls extending upward from a bottom wall to first and second shelves, respectively, on both sides of the disk receiving sheet. And a flange on the first side wall of the terminal member is received in isolation on the first shelf, and a flange on the second side wall of the terminal member is received in isolation on the second shelf. Are inserted between each shelf and each flange, and the distal ends of the side walls of the first and second housing members are each bent over the flange and the strip of electrically insulating material to form a housing portion. A housing securing the material to the terminal member, a temperature-sensitive disk placed on a disk receiving sheet and movable in a dish-shaped recess in the opposite direction, and opposing first and second ends. A movable contact arm, one end of which is cantilevered on the bottom wall of one terminal member and the other end is movable to engage and disengage with the bottom wall of the other terminal member. Wherein the motion-transmitting member extends from the movable contact arm to the temperature-sensitive disc and is moved when the temperature-sensitive disc is moved to one of the dish-shaped recessed configurations. A movable contact arm, wherein the sensitive disc transmits motion to the movable contact arm via the motion transmitting member and biases the movable arm to disengage from the other terminal member. 11. A switch unit and a heat sensing unit, wherein the heat sensing unit is placed on a disk sheet of the housing, and is movable during a configuration in which the heat sensing unit is recessed on the opposite side in response to a predetermined temperature condition. Wherein the disk sheet is coupled to the switch portion via a pair of opposing side walls, the switch portion biased to normally engage the stationary contact. Movable contact arm,
A method for calibrating a temperature sensitive electrical switch having a motion transmitting member extending from a movable contact arm to a top to a temperature sensitive disk, wherein the position of the motion transmitting member with respect to the movable contact arm is selected such that: Adjusting the motion transmission member to lie between the disk sheet and a plane parallel to the disk sheet spaced upwardly by an amount equal to the thickness of the disk; A first member having surfaces engaging the housing on both sides of the seat; a second, spring-loaded second member mounted movably with the first member and movable in a linear direction relative to the first member. A member having a surface engaging the bottom surface of the housing aligned with the disk sheet, secured to the second member, centered within the inner member, and in the linear direction; Providing a second member having a pin having a parallel longitudinal axis; and wherein the first member and the second member are separated while the first member is away from the housing. Engaging the housing while extending through the opening and moving the disk to lift above the disk sheet; and moving the first member such that the surface of the first member engages the housing; Move the first member further against the biasing force of the spring,
Deforming the side wall until the movable contact arm and the stationary contact are released from electrical engagement. 12. The method according to claim 11, wherein said selected gap is between about 0 mm and 0.2 mm.