JPH01227322A - Thermostat - Google Patents

Abstract

PURPOSE:To facilitate assembly work and to simplify adjustment by constituting such that a larger winding outer diameter portion of a tension spring comes in contact with a stopper just before a switch is turned on and parts from the stopper just before the switch is turned off. CONSTITUTION:When a switch 40 is turned off, a larger winding outer diameter portion 34 of a tension spring 32 does not come in contact with a stopper 36 but is in a floated condition. In order to turn the switch 40 off at any temperature, it suffices to adjust the force of the spring 32 with an adjustment screw 33. Because the force of the spring 32 changes with the displacement of a cam portion 29 due to the rotation of a cam shaft 30, turning off temperature changes in effect. In the case the switch is turned off, a larger winding outer diameter portion 34 of the tension spring 32 comes in contact with the stopper 36 of a device frame 22 and thereafter a smaller winding outer diameter portion 35 displaces. The force of the larger winding outer diameter portion 34 is prevented by the stopper 36 from being transmitted. The spring force just before the switch turning on is determined only by the force of the portion 35. As a result, temperature is constant regardless of the position of the cam 30.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a thermostat that controls the temperature of electric refrigerators, freezers, shower cases, etc. Specifically, rotating the temperature control dial changes the OFF temperature, but the ON temperature changes. This relates to a constant temperature return type thermostat that is two-constant.

BACKGROUND TECHNOLOGY As a prior art, there is an example as shown in Japanese Utility Model Publication No. 57-55716. As shown in Figure 4, 1 is a bellows that causes pressure changes depending on temperature, and 2 is a bellows 1.
A lever 3 that comes into contact with and is rotatable is a switch that is opened and closed by rotating the lever 20 times. The lever 2 is biased by a first spring 4 in a direction opposite to the output of the bellows 1.

Further, there is an arm 8 which is rotatably attached to the base frame 6, the i end engages with the stopper 6 of the base frame 6, and is connected to the lever 2 via an adjustable screw 7. One end is interlocked with a cam 9 rotatably attached to the frame 5,
The other end has a cam arm 11 to which a second spring 10 is attached, and the second spring 1o is engaged with the arm 8.

Here, when the temperature rises and the bellows 1 expands, the lever 2 rotates counterclockwise, resisting the bias of the first spring 4 and turning on the switch 3. Here, the force of the second spring 10 is such that the arm 8 does not move beyond the position where it is at the stopper e of the base frame 6.
If you adjust it so that it does not touch the lever 2 mentioned above,
Regardless of the position of the cam 9, the ON temperature is the same as that of the first spring 4.
It is controlled only by , so it is constant. Conversely, when the temperature drops, the bellows 1 contracts, the lever 2 rotates clockwise, and the switch 3 is turned off. At this time, lever 2 is
The switch 3 makes contact with the screw 7 before the FF position υ, and resists the bias of the second spring 1o via the arm 8.
must be turned off. Here, the cam bottom surface 12 is displaced depending on the rotational position of the contact surface of the cam arm 11, and the cam arm 11 is displaced together with the cam 9. Therefore, when the dial is turned to rotate the cam 9, the cam arm 11 is also displaced in conjunction with the second The tension of the spring 10 also changes.

Therefore, the spring force applied to the lever 2 also changes, making it possible to adjust the OFF temperature.

Problems to be Solved by the Invention In the prior art, the thermostat functions satisfactorily as a constant temperature return type thermostat, but requires a large number of parts for assembly, and adjustment points are limited to the first spring 4, second spring 10. There are four screws, including the screw 7 and the switching stroke adjustment screw 14 of the switch 3, which may result in time-consuming adjustment work.

It is something that

Means for Solving the Problems In order to solve the above problems, the thermostat of the present invention includes:
It consists of a lever that comes into contact with a pressure-responsive element and opens and closes the switch by its rotation, a cam arm that is rotatably attached to the base frame, and a tension spring that is attached between the lever and the cam arm. The diameter is smaller on the lever side and larger on the cam arm side, so that the larger part of the outer diameter of the tension spring comes into contact with the stopper just before the switch is turned on, and separates just before it is turned off.

With the above-described configuration, the present invention has the above-described configuration, so that the portion of the tension spring with a large outer diameter does not come into contact with the stopper immediately before the switch is turned off, and the turning-off force is generated by the spring with a large outer diameter displaced by the cam. It is determined by the combined spring force of the spring with a small outside diameter. Immediately before turning on, the part of the tension spring with a large outside diameter comes into contact with the stopper, and the spring force of the spring with a large outside diameter stops working, and the cam It is not affected by the force from the cam arm that is displaced by the winding, and only has a small spring force due to the outer diameter of the winding, so a constant temperature return type thermostat can be formed.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. 20 is a pressure-responsive element (
In this embodiment, the capillary is a bellows (hereinafter referred to as bellows), and a temperature detection capillary 21 of the control section detects temperature changes. The bellows 20 is attached by soldering to a housing 23 fixed to a base frame 22 forming the outer shell of the thermostat. Furthermore, a point piece 2θ is fixed to the tip of the bellows, and comes into contact with a lever 26 rotatably mounted around a fulcrum 24 provided on the side wall 22' of the base frame 22.

The lever 25 is formed in an abbreviated shape and has a head that comes into contact with the point piece 2e and a foot that engages with a fulcrum 24 provided on the base frame 22, and a foot that engages with a fulcrum 24 provided on the base frame 22. A spacer 27 made of an insulating material is attached.

Similarly to the lever 26, one end is rotatably engaged with a fulcrum 28 provided on the side wall 22' of the base frame 22, and the other end is rotatably engaged with a fulcrum 28 provided on the side wall 22' of the base frame 22.
2 has a flat plate-shaped cam arm 31 which is rotatably attached to the cam shaft 30 and comes into contact with the eccentric cam part 29 of the camshaft 30, and a hole 31a in which an adjustment screw 33 for adjusting the spring force of the tension spring 32 is installed have. As described above, one end of the tension spring 32 is attached to the cam arm 31 via the adjustment screw 33, and the other end is attached to the lever 26. It consists of a portion 36 with a small outer diameter, and the outer diameter of the winding is smaller on the lever 26 side and larger on the cam arm 31 side. Therefore, the portion 36 with a small outer diameter of the winding is replaced by the portion 34 with a large outer diameter of the winding.
It has a spring constant that is several times larger. Here, a stopper 36 formed by cutting and raising a part of the side wall 22' of the base frame 22 inward is provided between the large outer diameter portion 34 of the tension spring 32 and the load lever 26, and
The stopper 36 is arranged so as to be able to come into contact with the portion 35 having a large outer diameter.

Further, the snap switch 40 is held by a resin case 41, and the case 41 is fixed to the base frame 22. Further, the switching stroke of the snap switch 40 is adjusted by a differential screw 42 screwed into the case 41.

The operation of the thermostat configured as above will be explained.

Detects temperature changes in the control unit, such as snap switch 4
Consider the case where 0 is OFF. The output of the Siberose 20 changes depending on the temperature of the control part, and the snap switch 40 is turned off at an arbitrary temperature.

The force that moves the lever 26 in the OFF direction is determined by the force of the tension spring 32, that is, the combined force of the spring force of the portion 34 with the larger outer diameter of the winding and the spring force of the portion 35 with the smaller outer diameter of the winding. The small outer diameter portion 36 has a large spring constant, so it hardly stretches, and only the small outer diameter portion 34 of the winding is displaced. The portion 36 with the larger outer diameter of the winding and the stopper 36 do not come into contact with each other and are in a floating state. Here, in order to turn off the snap switch 40 at an arbitrary temperature, the force of the tension spring 32 may be adjusted using the adjustment screw 33. Further, since the force of the tension spring 32 changes due to the displacement of the cam portion 29 due to the rotation of the camshaft 3 degrees (mainly the portion 34 having a large winding outer diameter changes), the OFF temperature changes as a result. Next, consider the case of turning on. The force for moving the lever 25 in the ON direction can be varied by adjusting the switching stroke of the snap switch 40 and the differential screw 42.

When the switching stroke is increased, the lever 26 has to move more to turn on the snap switch 40, and as a result, the force of the tension spring 32 increases, and the portion 34 of the tension spring with the larger outer diameter At the same time, it moves to the lever 26 side.

At this time, the portion 34 of the tension spring 32 with the larger outer diameter contacts the stopper 36 of the base frame 22, and thereafter the portion 36 with the smaller outer diameter is displaced. The transmission of the spring force of the portion 34 with the larger winding outer diameter is blocked by the stopper 36 of the base frame 22. The spring force immediately before turning on is determined only by the spring force of the portion 36 with the smaller outer diameter of the winding. Therefore, the force for turning ON, that is, the temperature, is constant regardless of the position of the cam shirt 30.

As shown in FIG.
A constant temperature return type thermostat is formed in which the OFF temperature can be varied and the ON temperature is constant.

As mentioned above, the spring is only the tension spring 32, which is easy to assemble, and the adjustment point is the adjustment screw 33 for adjusting the tension spring 32.
There are only two places, the differential screw 42 for adjusting the switching stroke of the snap switch 4o, and the adjustment does not take much time.

Effects of the Invention As described above, the present invention provides a lever that contacts a pressure-responsive element and opens and closes a switch by its rotation, a cam arm that is rotatably attached to a base frame, and a mechanism that connects the lever and the cam arm. The outer diameter of the tension spring is smaller on the lever side and larger on the cam arm side, and the larger part of the outer diameter of the tension spring comes into contact with the stopper just before the switch is turned on. , since it is configured to separate immediately before turning off, (1) The spring is only a tension spring, which facilitates assembly and reduces costs.

(2) The conventional product took time to adjust the foot at 4 adjustment points, but the invented product only has 2 adjustment points: the adjustment screw that adjusts the force of the tension spring, and the differential screw that adjusts the switching stroke of the snap switch. Adjustment can be easily made by adjusting the .

As mentioned above, this is very effective in practice.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a thermostat showing an embodiment of the present invention, Fig. 2 is a perspective view of the main parts of the thermostat, Fig. 3 is a characteristic diagram of a constant temperature return type thermostat, and Fig. 4 is a diagram of a conventional thermostat. FIG. 2o...Pressure responsive element, 22...Base frame, 26...Lever, 4o...Switch, 3o...Cam, 31... ...Cam arm, 32...Tension spring, 36...
Stopper, 34... Portion with large outer diameter of winding, 35
・・・・・・Part with small outer diameter of the winding. Name of agent: Patent attorney Toshio Nakao and one other name
Pressure motion demon child 22-a frame 25-lever 2? -One force arm/l-Shoulder 31- Cam arm, 95-4 outer part or stopper Fig. 1 51-°-Switch P? -Base frame z5--Lever No. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] A pressure-responsive element filled with gas that causes a pressure change due to a temperature change in a control section; a lever that is rotatable about a part of a frame that comes into contact with the pressure-responsive element and forms the outer shell of the thermostat; and the lever. a cam arm having one end abutting a cam rotatably attached to the container frame with one end abutting on a part of the container frame as a fulcrum, and a cam arm having one end attached to the lever and the other end adjustable. The outside diameter of the tension spring is smaller on the lever side and larger on the cam arm side, and the stopper cut and raised from the device frame and the larger part of the outside diameter of the tension spring are turned on. The thermostat is arranged so that it comes into contact just before turning off and separates just before turning off.