JPH01302627A - Thermostat - Google Patents

Abstract

PURPOSE:To simplify the assembling and adjusting works and reduce the cost by forming the outer diameter of a tensile spring smaller on the lever side and larger on the cam arm side, bringing the portion of the tensile spring with the larger outer diameter and an adjustable stopper into contact with each other immediately before a switch is turned on, and separating them immediately before the switch is turned off. CONSTITUTION:The outer diameter of a tensile spring 33 is formed smaller on the lever 25 side and larger on the cam arm 32 side. In this case, a stopper 37 slidably fitted to a frame 22 and located contactably with the portion of the tensile spring 33 with the larger diameter and having a means to adjust the position in contact with the portion of the spring 33 with the larger diameter is provided so that the stopper 37 and the portion of the spring 33 with the larger diameter are brought into contact with each other immediately before a switch is turned on and they are separated immediately before the switch is turned off. Only one tensile spring 33 is used, no connecting piece or the like to connect two springs is required, assembling is facilitated, the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thermostat that controls the temperature of electric refrigerators, freezers, showcases, 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.

BACKGROUND TECHNOLOGY As a prior art, there is an example as shown in Japanese Patent Publication No. 57-36694. As shown in FIG. 4, 1 represents the output of the bellows, which causes pressure changes due to temperature, as a load P. Reference numeral 2 denotes a lever that is rotatably moved around a fulcrum 3 by a load P.

4 is a switch that is opened and closed by rotating the lever 2; 6 is a first spring that is biased in the opposite direction to the output of the load P, and 6 is a second spring that is connected in series with the first spring.
In the spring, 7 is a connecting piece that connects the first spring and the second spring.

8 is a cam arm that is displaced about a fulcrum 10 by a cam 9; 11 is an adjuster l screw attached to the cam arm 8 for adjusting the tension of the second spring 6; Reference numeral 12 denotes a stopper provided at a position in contact with the connecting piece, and the stopper position can be freely adjusted.

Here, when the temperature rises and the load P1 increases -r, the lever 2 rotates in the backward and forward direction, resisting the bias force of the first spring 5 and turning on the switch 4.

Here, the force of the first spring 5 is constant because the connecting piece 7 does not move beyond a certain position due to the stopper 12, regardless of the displacement of the cam 9, and the ON temperature is controlled only by the first spring 5. Since the tension of the spring 2 and the spring 6 are not related when the spring is ON, the ON temperature is constant.

Conversely, when the temperature rises, the load P1 decreases, the lever 2 rotates counterclockwise, and the switch 4 is turned off.

At this time, the connecting piece 7 separates from the stopper 12 before reaching the OFF position, and is operated by the combined force of the first spring 5 and the second spring 6 when the connecting piece 7 is OFF.

The cam arm 8 is displaced together with the cam 9. When the cam 9 is rotated, the cam arm 8 is also displaced 1-7, and then the second
As the tension of the spring 6 also changes, the first
The OFF temperature was also changed by changing the combined force of the spring 5 and the second spring 6.

Problems to be Solved by the Invention In the prior art, although the thermostat functions satisfactorily as a constant temperature return type, it is necessary to incorporate two tension springs during assembly, and a connecting piece is required to connect the two springs. It was necessary to use a varnish, which took time to assemble, and was an obstacle to reducing the amount of varnish.

The present invention aims to provide a thermostat that is easy to assemble, easy to adjust, and inexpensive, with a 2-dimensions ν and θ.Means for solving the problems mentioned above. In order to solve this problem, the thermostat of the present invention includes: 2, a lever that comes into contact with the force-responsive element, 2, a lever that opens and closes the squirrel opening by its rotation, and a cam arm that is rotatably attached to the device frame; It consists of a tension spring installed between the lever and the cam arm, and 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 serves as an adjustable stopper. It comes into contact with the switch just before it turns on,
It is configured so that it leaves immediately before being turned off.

Effect: Due to the above-described configuration, the part of the tension spring with the large outer diameter of the tension spring does not come into contact with the stopper immediately before the switch is turned off, and the turning-off force is the result of the outer diameter of the tension spring displaced by the cam. It is determined by the combined spring force of the spring and the spring with a small outer diameter, and immediately before turning on, the part of the tension spring with the outer diameter comes into contact with the stopper 17.
The spring force of the spring that is the outer diameter of the winding is no longer applied, and the force from the cam arm that is displaced by the cam is not affected by the force 14, and only the small spring force of the outer diameter of the winding becomes constant.
'1111il: A reset type thermostat can be formed.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1, 2, and 3. 2o is a pressure-responsive element (in this example, a bellows, hereinafter referred to as a bellows) that has a gas sealed inside.
t) in the temperature detection capillary 21 of the control section,
Detects all temperature changes. The bellows 20 has a housing 23 fixed to a container frame 22 forming a thermostat outer shell.
It is attached by soldering. A point piece 26 is fixed to the tip of the bellows, and comes into contact with a lever 25 that is rotatable about a fulcrum 24 provided on the side wall 22a of the container frame 22.

The lever 25 is formed in an abbreviated shape, and the lever 25 is
It has a head that comes into contact with the piece 26 and a foot that fits into the fulcrum 24 provided on the vessel frame 22, and is made of an insulating material that opens and closes the end of the switch 2.
8 is installed.

Similarly to the lever 25, one end is rotatably engaged with a fulcrum 29 provided on the side wall 22a of the container frame 22, and the other end is rotatably engaged with a fulcrum 29 provided on the side wall 22a of the container frame 22.
2, there is a flat plate-shaped cam arm 32 which is rotatably attached to the camshaft 31 and comes into contact with the eccentric cam part 3° of the camshaft 31, which has an eccentric cam part 30; 32a.

As described above, one end of the tension spring 33 is attached to the cam arm 32 via the adjustment screw A34, and the other end is attached to the lever 25. It consists of a portion 36 with a smaller diameter, and the outer diameter of the winding is smaller on the lever 25 side and larger on the cam arm 32 side. Therefore, the portion 36 with a smaller outer diameter of the winding has a spring constant several times larger than the portion 36 with a larger outer diameter of the winding. Here, a stopper provided so as to freely come into contact with the tension spring 33
37 is an abbreviated shape, and a part is two rectangular pieces 37a.
The other part of the tension spring 330 is arranged so as to be slidable between the container frame 22 and the camshaft 31, and the diameter of the other part is larger than the diameter of the part 36 with the smaller outer diameter of the tension spring 330 and the part 35 with the larger outer diameter of the tension spring 330. It has a semicircular notch smaller than the diameter, and has a screw hole 40 for inserting an adjustment screw B39 at the other end. The adjustment screw B39 has one end inserted into the screw hole 40.
The other end is arranged through a hole 41 in a part of the rear wall 22b of the container frame 22 so as to be freely adjustable.

Further, the snap switch 27 is held by a resin case 42, and the case 42 is fixed to the container frame 22. Further, the switching stroke of the snap switch 27 is adjusted by a typhoid screw 43 screwed into the case 42.

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

Detects temperature changes in the control unit, such as snug switch 2.
Consider the case where 7 is OFF. The output of the bellows 20 changes depending on the temperature of the control part, so that the snap switch 27 can be turned off at an arbitrary temperature.

The force that moves the lever 26 in the OFF direction is
The force of the tension spring 33, that is, the portion 3 where the outer diameter of the winding is large
It is determined by the combined force of the spring force of 6 and the spring force of the part 3θ where the winding outside diameter is small, but the part 36 where the winding outside diameter is small has a large spring constant, so it hardly stretches, and the winding outside diameter is almost the same. Only a small portion 36 is displaced.

Here, by screwing in the adjustment screw B39 screwed into the screw hole 4o of the stopper and sliding the stopper 37, the notch 38 of the stopper and the large outer diameter portion 36 of the tension spring 33 are connected. Do not let them touch each other and let them float. At this time, in order to turn off the snap switch 3 at an arbitrary temperature, the force of the tension spring 330 can be adjusted using the adjustment screw 34.

In addition, the force of the tension spring 33 changes due to the displacement of the cam part 30 due to the rotation of the camshaft 310 (mainly 1
(The large part 35 of the outer diameter of the winding changes) As a result, it turns OFF.
Temperature changes. Next, consider the case of turning on. The force for moving the lever 25 in the QN direction can be varied by adjusting the switching strobe of the snap switch 27 and the differential screw 43.

When the switching stroke is increased, the lever 26 has to move more to turn on the snap switch 27, and as a result, the force of the tension spring 33 increases, and the portion 35 of the tension spring with the larger outer diameter 25, moves to the lever 25 side.

At this time, the portion 36 of the tension spring 33 with the larger outer diameter comes into contact with the notch 38 of the stopper 37, and thereafter only the portion 36 with the smaller outer diameter is displaced.

A stopper 37 blocks transmission of the spring force of the portion 36 with a larger outer diameter. 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 camshaft 31.

Therefore, depending on the position of the camshaft 31, 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 the tension spring 33.
Since there is no need for a connecting piece to connect the two springs, assembly is easy and the number of parts is small, reducing costs.

Effects of the Invention As described above, the present invention comprises: a lever that comes into contact with a pressure-responsive element and opens and closes a switch by its rotation; a cam arm that is rotatably attached to a thin frame; and the lever and the cam arm. Consists of a tension spring installed between
The outer diameter of the tension spring is smaller on the lever side and larger on the cam arm side, and is slidably attached to the thin frame and positioned so as to be able to freely come into contact with a dog-shaped portion of the diameter of the tension spring. and a stopper having a means for adjusting the position of contact with the diameter part of the spring, and the stopper and the slightly larger part of the spring are switched ON (contact 1 to OFF before settling).
Since the groove is formed so that the springs are separated just before the spring is released, the present invention uses only one tension spring, whereas the conventional method uses two springs, and the connecting piece etc. that connects the two springs is used. This eliminates the need for assembly, making it easy to assemble and reducing costs.

[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 plan view of essential parts of the thermostat, Fig. 3 is an exploded perspective view of the thermostat, and Fig. 4 is a schematic diagram of a conventional thermostat. It is. 20...Pressure responsive element, 22...2g
Frame, 25...Lever, 27...Switch, 30...-1j arm, 32...Cam arm, 33...Tension spring, 37...
7-1-Soba-135... Part with a large outer diameter of the winding, 36... Part with a small outer diameter of the winding. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure-1,59-

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 switch that opens and closes with a cam arm, one end of which is in contact with a cam that is rotatably attached to the instrument frame with one end on a part of the instrument frame as a fulcrum, and one end of which is attached to the lever and the other end that is adjustable and attached to the cam arm. The outer diameter of the tension spring is smaller on the lever side and larger on the cam arm side. comprising a stopper that is movably positioned and has means for adjusting the position of contact with the large diameter portion of the spring, the stopper and the large diameter portion of the spring contacting each other immediately before the switch is turned on; The thermostat is placed so that it moves away just before it turns off.