JPS5922572Y2 - Cam plate operation load balancing device - Google Patents

Description

[Detailed description of the invention] This invention is applicable to a device such as a thermostat in which the operating temperature is set by rotating a cam plate and changing the tension of a counter spring that opposes the pressure corresponding to the operating temperature. There is a large difference in operating torque in both directions: when the cam plate rotates from a small radius to a large radius, and when the cam plate rotates from a large radius to a small radius. This relates to a device that balances the air so that it does not occur.

Figures 1 and 2 are a plan view and a sectional view showing the structure of a well-known thermostat, in which a temperature sensing part (not shown) contacts a bellows 5 which shows a gas pressure corresponding to the temperature, and the bellows expands and contracts. an actuating plate 4 that rotates at the angle of 40 degrees, a counter spring 3 that is attached at one end to the actuating plate 4 and attached to the freely tiltable adjusting plate 2 via an adjusting screw 6; It has a rotatable cam plate 1 that changes the tilting angle of the plate and the tension of the opposing spring 3, and the operating temperature is set by changing the tension of the opposing spring 3 by rotating the cam plate 1.

Therefore, when setting the temperature, when rotating the cam plate 1 from the small radius R2 of the cam plate in the direction of the large radius R1 (counterclockwise in Fig. 1), the opposing spring 3 is free to expand and the tension is large. The opposing operation rotational torque requires, for example, 1.9 kgcm to 2.0 kg-cm, as shown in FIG. (in the clockwise direction), the opposing spring contracts as shown in the opening of Figure 3, so a rotational torque of, for example, 1.0 kg-cm to 0.7 kg-cm is sufficient, and depending on the direction of rotation of the cam plate, There is a difference in operating torque.

This means that when the user sets the temperature, the operating torque for rotating the cam plate differs depending on the direction of rotation, so the feeling will be different when rotating clockwise and counterclockwise. In particular, there is a demand for thermostats with transverse setting knobs to be able to be operated with the rotational torque of the cam plate that is not much different when the knob is moved from left to right or from right to left. The present invention has been developed to meet the above requirements, and in the case of the rotation shown in Fig. 3A, the rotational torque due to the counter spring is reduced, and in the case of the same rotation, the rotational torque is increased. It is an object of the present invention to provide a cam operation load balancing device in which a spring is wound around a cam shaft to reduce the difference in operation rotation torque between the rotation shown in FIG. 3A and the rotation of the opening.

The present invention will be explained below with reference to the illustrated embodiments.

In this embodiment, a case will be described in which the present invention is applied to a thermostat having a transverse knob.

FIG. 6A shows a broken cross-sectional view of the thermostat cam part. The cam plate 1 is fixed to the cam shaft 1a, the cam shaft is rotatably supported by the casing C, and the cam plate 1 is attached to the adjustment plate. It is in contact with the upper end of 2.

A lever 7 integral with the cam plate 1 is extended, the tip of the lever 7 is formed in a trident shape, and a transverse roller 8 integral with a transverse knob (not shown) is held on the inner surface of the bifurcated shape. The roller 8 is moved along the axis X--X by a knob, and rotates the cam plate 1.

A screw spring 9 is wound around the camshaft 1a, and one end 9a of the spring 9 is wound around the camshaft 1a.
is fixed to a point 1b on the cam plate, and the other end 9b is fixed to the casing C.

The state shown in FIG. 6-A shows a state in which the adjustment plate 2 is in contact with the point where the radius of the cam shaft of the cam plate 1 is the smallest,
The tension of the counter spring 3 is the minimum, and in this case, the torsion spring 9 has the maximum load on the camshaft, and when the roller 8 is moved to the right by pinching the cam plate 1, the cam plate 1 rotates counterclockwise. As a result, the tension of the opposing spring 3 increases, but the torsion spring 9 becomes untightened and assists the rotation of the cam plate 1.

At the position where the cam plate 1 has the maximum radius from the cam shaft and the adjustment plate abuts, the tension of the opposing spring 3 is maximum and the torsion spring is minimum, resulting in the state shown in Figure 6.

From this state, when the roller is moved to the left in the figure by the knob, the cam plate 1 rotates clockwise, and the tension of the opposing spring 3 gradually decreases, but the torsion spring 9 is tightened and the load increases. Finally, the state shown in FIG. 6A is reached, where the load of the torsion spring is maximum.

Figures 4 and 5 are diagrams showing the above aspects.
The figure shows an example of a torque change due to the rotation of the cam plate of a torsion spring, and shows an example of the torque change due to the rotation of the cam plate of the torsion spring. The torque of is 0.6 kg-cm, and the torque of the screw spring 9 at the opening in FIG. 6 is 0.2 kg-cm.

FIG. 5 shows the working mode of the cam operation load balancing device of the present invention equipped with a torsion spring 9. Point a in the figure is the position where the minimum radius point of the cam plate 1 and the adjustment plate 2 come into contact. The line a-b shows the state in which the cam plate 1 is rotated counterclockwise from point a, and at point a, the torque of the opposing spring is <1.9 kg-cm as shown in Fig. 1. However, the torque in the opposite direction of the torsion spring is <0.6 kg-cm as shown in FIG. 4, and therefore the rotational torque for cam operation is 1.3 kg-cm.

Point b indicates the position where the maximum radius of the cam contacts the adjustment plate, and the torque of the opposing spring 3 at this position is 2.0 kg.
cm, the screw spring torque in the opposite direction is 0.2 kg-cm
The operational rotation torque is 1.8 kg-cm.

Line C-d shows the case where the cam plate 1 is rotated clockwise from the state of point b on line a-1), and at point 0, the counter spring 3
To the torque of 1.0 kg-cm, the torque of the torsion spring of 0.2 kg-crn is added, resulting in 1.2 kg-crn, and at point d, the torque of the opposing spring is 0.7 kg-cm.
To this, 0.6 kg-cm of torque from the torsion spring is added, resulting in a torque of 1°3 kg-cm.

In the above example, a torsion spring having the torque characteristics shown in Fig. 4 is wound around the camshaft for a thermostat that requires operating rotational torque for a counter spring as shown in Fig. 3, and the counterclockwise rotation of the cam plate is The torque of the torsion spring acts in the direction of decreasing the torque of the opposing spring, and the clockwise rotation of the cam plate is made to act in a manner that adds to the torque of the opposing spring. Compared to the case shown in Fig. 3 where the cam plate is not used, the operating rotation torque values in the case of counterclockwise rotation a-1) and clockwise rotation C-d of the cam plate are close to each other and are significantly improved. It is shown that.

As explained above, the present invention uses a type of thermostat that sets the temperature by changing the tension of a counter spring by rotating the cam plate, and the operating load when the cam plate is rotated counterclockwise or clockwise. By wrapping a torsion spring around the camshaft,
It is balanced so that there is not much difference in either case,
Although the above embodiment shows an example in which the present invention is applied to a thermostat, the present invention is not limited to this, but can also be applied to, for example, a pressure switch, and the desired purpose can be achieved with a simple device.

[Brief explanation of the drawing]

Figures 1 and 2 show the structure of a well-known thermostat. Figure 1 is a plan view, Figure 2 is a sectional view, and Figure 3 is a diagram showing the structure of a known thermostat. FIG. 4 is a diagram showing an example of the rotational torque of a torsion spring; FIG. 6 is a cutaway cross-sectional view of the main part of the present invention, and FIG. 6 is a plan view showing the mode of the torsion spring at the minimum load. 1...Cam plate, 1a...Cam shaft, 2...
...Adjustment plate, 3...Counter spring, 4...
...Operating plate, 5...Bellows, 6...
・Adjustment screw, 7... Lever 8... Transverse loaf, 9... Torsion spring.

Claims (1)

[Scope of utility model registration request] In a device that rotates a cam plate fixed to a camshaft and changes the tension of a counter spring to set an operating value, when the cam plate rotates in one direction, the cam operation load that opposes the tension of the counter spring is reduced. When the cam plate rotates in the other direction, a torsion spring that acts in a direction that adds to the cam operation load opposing the counter spring tension is fixed at one end to the cam plate and at the other end. is fixed to another fixed point and wound around the camshaft, so that the cam plate operating load is almost balanced when the cam plate rotates in any direction. .