JPH039234Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for adjusting the operating point of a movable plate that performs a reversal operation in conjunction with the bending of the main bimetal in a thermal overload relay.

[Prior art and its problems]

A conventional device of this kind is shown in FIG. 6, which is a front view of the main part thereof. In Fig. 6, inside the insulating case 1 is a main bimetal (only one phase is shown) around which a heating element inserted into each three-phase electric circuit is wound.
, a shifter 6 that is engaged with each of the free ends of the main bimetal 2 and supported so as to be movable in the direction of arrow P along a guide groove formed in the case 1; An opening/closing mechanism 3 disposed in the opening/closing mechanism 1 and a contact device 4 that is operated to connect and separate by the opening/closing mechanism 3 via a reversing mechanism 5 are housed as main components. The opening/closing mechanism 3 includes a temperature compensating bimetal 8 whose adjusting screw 7 attached to the tip engages with one end of the shifter 6, and a release lever in which the temperature compensating bimetal 8 is integrated and is rotatable about a pivot point X. 9, an adjustment link 10 that intervenes between the adjustment dial 12 and the release lever 9 and is rotatable around a fulcrum W, and a tongue piece 10 of this adjustment link 10.
The spring 11 has one end fixed to the spring a and the other end fixed to the case, and presses the head 10b of the adjustment link 10 toward the eccentric shaft 12a of the adjustment dial 12. The reversing mechanism 5 includes a movable plate 16 including an insulator 17, one end of which is inserted into a V-shaped groove 13a formed in the terminal plate 13, and the normally open side movable contact 15 of the contact device 4 is attached to the other end. , terminal board 13
A tension member is stretched between the sawtooth groove 13b and the movable plate 16, and when its line of action crosses the V-shaped groove 13a (point Z) that supports the movable plate 16, the movable plate 16 is reversed. It consists of a spring 14. The contact device 4 includes a movable plate 16 and a terminal plate 13, to which an insulator 17 is attached, which drives the normally open side movable contact 15 and the normally closed side movable contact 18, which partially serve as the above-mentioned reversing mechanism 5. , normally open side movable contact 15
A normally open side movable contact 20 is arranged opposite to the case 1 and fixed to the case 1 by a terminal plate 21, and a normally closed side movable contact is fixed to the case 1 by a terminal plate 19 driven by an insulator 17 by the operation of the movable plate 16. 18, and a terminal plate 23 arranged opposite to this normally closed side movable contact 18.
Normally closed side fixed contact 22 fixed to case 1 by
Consisting of

In the thermal type overload relay shown in FIG. 6, when an overcurrent flows through the heating element (not shown), the main bimetal 2 bends due to the temperature rise due to the heat generated by the heating element, and the shifter 6 is bent by the displacement of its free end. Move in the P arrow direction. When the shifter 6 moves, the adjustment screw 7 attached to the tip of the temperature compensating bimetal 8 is pressed, and the release lever 9 rotates clockwise around the pivot point X, which causes the tension spring 1 of the reversing mechanism 5 to rotate.
4 is moved in the Q arrow direction.
At this time, the initial rotation angle of the release lever 9 with which the temperature compensation bimetal 8 is integrated is set by the adjustment dial 1.
It is set to a predetermined value by the left and right movement of the pivot point X by the adjustment link 10 in conjunction with the rotational adjustment of No. 2. When the release lever 9 further rotates and the line of action of the tension spring 14 passes beyond the dead center, the movable plate 16 reverses from the illustrated state with Z as a fulcrum.

In this thermal type overload relay, the movable plate 16 is
There are cases where the operating point at which the reverse operation occurs varies or there are cases where the operation does not occur. An adjustment screw 7 is provided to absorb such variations and to keep the operating point constant. For example, if there is a gap between the engagement part of the shifter 6 and the temperature compensation bimetal 8 due to positioning or dimensional variations, the release lever 9 will not rotate even if an overcurrent flows through the heating element and the main bimetal 2 bends. is reduced by the amount of time, and even though an overcurrent is detected by the main bimetal 2, the line of action of the tension spring 14 does not cross the dead center, resulting in the inconvenience that the movable plate 16 does not perform the reverse operation. Therefore, in this case, by inserting a screwdriver or the like through the case opening 24 and screwing in the adjusting screw 7, the normal operating point can be obtained without any gaps. If the reversal movement of the movable plate 16 is too fast due to the above-mentioned variations, the normal operating point can be obtained by unscrewing the adjusting screw 7. However, in this conventional device, since the adjusting screw 7 is attached to the tip of the temperature compensating bimetal 8, not only the vibration resistance is impaired, but also external force is applied during adjustment, resulting in a deterioration of adjustment accuracy. Furthermore, since the adjustment screw 7 must be adjusted from the direction of movement of the shifter 6, it is necessary to provide a case opening 24 on the side of the case 1 for inserting a screwdriver, etc., which reduces the strength of the case side wall and prevents the case from opening. In order to prevent foreign matter from entering through the opening 24, the case opening 24 must be sealed with a seal (not shown) after adjustment, resulting in an increase in costs.

[Purpose of invention]

An object of the present invention is to eliminate the drawbacks of conventional devices and to provide an inexpensive device with good vibration resistance and workability without deteriorating adjustment accuracy.

[Key points of the idea]

The key points of the present invention are a temperature-compensating bimetal to which the displacement of the main bimetal that curves based on overcurrent is transmitted via a shifter, a release lever to which the temperature-compensating bimetal is attached, and a release lever having one end connected to the release lever. An adjustment link whose other end is pressed against the eccentric shaft of an adjustment dial, and a contact mechanism that opens and closes via a reversing mechanism operated by rotation of the release lever, one end of which is rotatable from outside the device. press-fit and hold an adjustment shaft having an eccentric cam that comes into contact with the eccentric shaft of the adjustment dial into the adjustment link;
The adjustment shaft is rotated from outside the device, the contact position of the eccentric cam of the adjustment shaft with the eccentric shaft of the adjustment dial is changed, and the adjustment link is rotated, thereby increasing the distance between the temperature compensation bimetal and the shifter. Between〓
This is an adjustment device for thermal overload relays that finely adjusts the temperature.

[Example of idea]

1 to 5 show an embodiment of the present invention, and the same parts in FIG. 1 as those shown in FIG. 6 are given the same reference numerals, and the explanation thereof will be omitted.

The embodiment of the present invention shown in FIG. 1 differs from the conventional device shown in FIG. 6 in that a general adjustment link 30 and an adjustment shaft 31 are attached to this adjustment link 30. Here, the adjustment link 30 is rotatable around the fulcrum W, and one end of the spring 11 is locked to the tongue piece 30a, and the part that holds the release lever 9, which is rotatable around the fulcrum X, is No different from before. As is clear from FIG. 2 showing a front view thereof, FIG. 3 showing a side view thereof, and FIGS. 4 and 5 showing plan views of different performances, the adjustment link 30 has an adjustment shaft 31 on the head 30b. is installed. The adjustment link 30 includes a support piece 30c that press-fits and holds the adjustment shaft 31, and a head 30b.
(step 3 of the adjustment shaft 31, which will be described later)
The adjustment shaft 31 is provided with an eccentric shaft 12 of the adjustment dial 12 which is eccentric from the center of the shaft.
There are provided an eccentric cam 31b that comes into contact with a, a groove 31a for rotatably holding it, and a stepped portion 31c for preventing it from coming off.

Next, in FIG. 1, due to variations in the positioning of the adjustment dial 12 and the main bimetal 2 and variations in individual parts, a gap t occurs between the engagement portion of the temperature compensation bimetal 8 and the shifter 6, and the heating wire (not shown) Even if an overcurrent flows and the main bimetal 2 bends, the amount of rotation of the release lever 9 is small by the amount of time t, and the movable plate 1
6 does not perform the reversal operation, the adjustment will be explained. In this case, by rotating the adjustment shaft 31 attached to the head 30b of the adjustment link 30 so that it can be turned from the front of the relay, the adjustment link 30 is press-fitted and held as shown in FIGS. 4 and 5. Adjustment dial 1 of the eccentric cam 31c from the shaft center
The dimension to the surface that comes into contact with the eccentric shaft 12a of No. 2 is La
It is possible to vary from Lb to Lb. Here, the eccentric cam 31b is in contact with the eccentric shaft 12a of the adjustment dial 12 supported by the case 1, and the adjustment link 30 is rotatably supported on the case 1 with W as a fulcrum. As a result of the rotation, the head 30b of the adjustment link 30 rotates in the direction of the arrow H, and the pivot point X of the adjustment link 30 rotates in the direction of the arrow I, using W as the fulcrum.
When the pivot point X moves in the direction of the arrow I, the tip of the temperature compensation bimetal 8 integrated with the release lever 9 moves in the direction of the arrow J around the pushing part 9a of the release lever 9 that comes into contact with the midsection 14a of the tension spring 14. do. Therefore, by rotating the adjustment shaft 31, the tip of the temperature compensation bimetal 8 moves in the direction of the shifter 6.
You can eliminate the time.

In this embodiment, the adjustment shaft 31 is the adjustment link 3
0, when adjusting the adjustment shaft 31, no external force is applied to the temperature compensation bimetal 8 or the release lever 9 unlike in conventional devices, and the distance from the fulcrum W to the adjustment shaft 31 is Since it is short compared to the distance to the shaft fulcrum X, the adjustment of the adjustment shaft 31 can be magnified and transmitted.
The adjustment between the temperature compensating bimetal 8 and the shifter 6 can be made sufficiently by providing the eccentric cam 31b in the shifter 1. Further, the adjustment link 30 is pressed against the eccentric shaft 12a of the adjustment dial 12 by the spring 11, and the adjustment shaft 31 is supported by its support piece 30c.
Since it is press-fitted into the round hole of 0, the adjustment screw 31
It does not loosen and has good vibration resistance. Also, the adjustment shaft 31
The adjustment link 3 is provided with a stepped portion 31c.
It never deviates from 0 and falls off.

[Effect of idea]

According to the present invention, the adjusting shaft is provided on the head of the adjustment link, and is rotatable from the front side of the relay, and is equipped with an eccentric cam that comes into contact with the eccentric shaft of the adjustment dial, so that the adjustment shaft can be adjusted from the front side of the relay. This allows fine adjustment of the distance between the shifter and the temperature-compensating bimetal integrated into the release lever. In this way, the gap between the temperature compensation bimetal and the shifter, which occurs due to variations in the positioning of the main bimetal or variations in the dimensions of individual parts, can be adjusted by adjusting the adjustment shaft press-fitted into the adjustment link. The adjustment work is simple, and unlike conventional devices, external force is not applied to the temperature compensation bimetal or release lever during the adjustment work, so it has the advantage that the adjustment accuracy that has been adjusted will not deteriorate. . Further, unlike conventional devices, there is no need to provide an opening for inserting a screwdriver or the like, and there is no need to seal the opening after adjusting the adjustment screw, and there is no need for screw processing, so costs can be reduced. Furthermore, since the adjustment shaft is press-fitted into the adjustment link, it will not loosen and has good vibration resistance.

[Brief explanation of drawings]

Figures 1 to 5 each show an embodiment of the present invention, with Figure 1 being a front view of the main parts of a thermal overload relay, Figures 2, 3, 4 and 5 respectively. A front view, a side view, and a plan view of the adjustment link in different states, and FIG. 6 is a front view of a main part of a conventional device. 2: Main bimetal, 6: Shifter, 8: Temperature compensation bimetal, 9: Release lever, 12: Adjustment dial, 12a: Eccentric shaft, 30: Adjustment link, 30
d: Round hole, 31: Adjustment shaft, 31c: Eccentric cam.

Claims (1)

[Scope of utility model registration request] A temperature-compensating bimetal to which the displacement of the main bimetal that curves based on overcurrent is transmitted via a shifter, a release lever to which this temperature-compensating bimetal is attached, one end of which is connected to the release lever, and the other end of which is connected to an adjustment dial. An adjustment link pressed by an eccentric shaft and a contact mechanism that opens and closes via a reversing mechanism operated by rotation of the release lever, which is rotatable from outside the device and has an eccentricity of the adjustment dial at one end. An adjustment shaft having an eccentric cam that contacts the shaft is press-fitted and held in the adjustment link, and the adjustment shaft is rotated from outside the device to change the contact position of the eccentric cam of the adjustment shaft with the eccentric shaft of the adjustment dial. A thermal overload relay characterized in that the distance between the temperature compensating bimetal and the shifter is finely adjusted by rotating the adjustment link.