JP2000276992A - Thermal overload relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal overload relay, realizing the simplification and cost reduction of a structure used for preventing an adjustment lever from easily coming off from a shaft due to shock, etc., and for preventing an adjusting screw of a current adjustment part from coming loose, and not suffering such a trouble that the relay is easily locked when a reset button is depressed. SOLUTION: An adjustment lever 80 of this thermal overload relay R has a shaft hole 81, the shaft hole is partly cut out on the opposite side to the incorporated side, a shaft 12 is provided with shafts on both ends thereof, and the adjustment lever 80 is rockably mounted thereon with its shaft hole 81 positioned at the shaft. The adjustment lever 80 is provided with an adjustment screw 84 threadably engaged therewith and having an end abutting on a circumferential surface of an adjustment cam 140, and surfaces of the adjustment screw 84 are coated with a soft resin for loosening prevention. An impeding projection is provided in a case 1 for giving resistance to a preset button 9 provided depressibly and rotatably around its axis when it is rotated around its axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal overload relay which is used in combination with an electromagnetic contactor or independently, and is mainly used for protecting an induction motor from burning. More specifically, the support structure of the adjustment lever that prevents the support part from coming off easily, the structure of the current adjustment unit that simplifies the structure by reducing the number of parts and reduces the cost, and locks the reset button at reset is easy. The present invention relates to a thermal overload relay including a structure of a reset unit that prevents the occurrence of the reset operation.

[0002]

2. Description of the Related Art FIG. 10 shows the structure of a conventional thermal overload relay, in which a back cover is removed, FIG. 11 is an exploded perspective view showing a conventional adjusting lever support structure, and FIG.
FIG. 3A shows a structure of a conventional reset unit, FIG. 4A shows an initial state, FIG. 4B shows a state in which an operating rod is reset by pushing down, and FIG. It is.

In a conventional thermal overload relay r, two sets of contacts 4a and 5a consisting of fixed contacts and movable contacts are arranged above and below substantially the center of a contact switching mechanism 2a of a case 1a made of an insulating material. I have. The movable contact has a movable contact plate provided with a movable contact, and the movable contact plate is attached to one end of the terminal portion. An operating rod 6a is swingably mounted between the contacts 4a, 5a. The operating rod 6a is provided with a pressing portion which is located on the front side of the movable contact plate and controls opening and closing of the contact. In a state before the operation, the operation assisting mechanism 7a inclines leftward as shown in FIG. 10, one contact 4a is closed, and the other contact 5a deflects the movable contact plate to open.

(Adjustment Lever Support Structure) An adjustment lever 80a for adjusting the operation sensitivity by swing adjustment is provided near the operation rod 6a. The adjusting lever 80a is provided with shaft holes 81a and 82a provided at two places on the coaxial line in the middle part.
Is fitted into a shaft member 12a provided in the case 1a and is swingably attached. The shaft member 12a has a structure in which a side portion is attached to the inner surface of the case 1a by a connecting portion 120a while leaving a part of the tip end side of the round bar body (see FIG. 11). By fitting the formed shaft hole 82a on the side opposite to the built-in side into the shaft member 12a, the rotation range of the adjustment lever 80a is limited to a certain range.

(Structure of Current Adjusting Unit) An adjusting screw 84a is threaded in the left and right direction near the switch knob at the upper end of the adjusting lever 80a. A leaf spring-shaped pressing piece 84b is provided above the adjusting lever 80a.
The fixing screw 84a is fixed in contact with the tip of the adjusting screw 84a by interposing a pressing piece 84b between the adjusting screw 84a and the adjusting cam 140a. The switch knob is used for manually setting the operation state at the time of performing a test or the like. The adjustment screw 84a operates by adjusting the set interval between the upper part of the adjustment lever 80a and the adjustment cam 140a provided on the adjustment dial 14a. This is for adjusting the sensitivity.

(Structure of Reset Unit) The reset button 9a is
A case 1a corresponding to one end of the operating rod 6a is provided through the case 1a, and a pressing member 90a and a locking member 91a are provided inside the case 1a. The reset button 9a is urged by a return spring 92a and is always pushed upward. By pushing the reset button 9a downward,
The pressing member 90a is used as the reset arm 67a of the operating rod 6a.
(Not shown in FIG. 12) in the return direction (FIG. 12).
(States from (a) to (b)), when the reversing plate 73a exceeds the dead center, the operating rod 6a after operation can be returned to the state before operation. Further, the reset button 9a is rotated in the clockwise direction in the pressed state (the state shown in FIGS. 12B to 12C), so that the locking portion 910a provided at the leading end of the locking member 91a is provided on the inner surface of the case 1a. Can be locked by being locked to the locking receiving portion 15a provided in the first portion.

[0007]

However, the following problems are involved in the structure of the adjusting lever support structure, the structure of the current adjusting unit, and the structure of the reset unit in the conventional thermal overload relay as described above. there were. (A) In the support structure of the adjustment lever, since there is no portion to be hooked on the shaft member, the adjustment lever is easily detached from the shaft member by a slight impact or the like with the back cover removed during manufacturing or maintenance. was there.

(B) In the structure of the current adjusting section, a pressing piece is provided to prevent the adjusting screw from being loosened. Since the pressing piece uses a material different from that of the adjustment lever,
It cannot be integrally formed by molding or the like, but is a so-called retrofit. Therefore, it takes time to make the adjustment lever, and the cost increases together with the parts cost.

(C) In the structure of the reset section, when the reset button is pressed, even if there is no intention of locking, the lock may be locked by a delicate movement of the operated finger. The operation to release the lock had to be performed, which was wasted time.

(Object) The object of the present invention is to solve the above-mentioned problem. A first object of the present invention is to remove the back cover at the time of manufacturing or maintenance, and to easily adjust the adjustment lever from the shaft member by a slight impact or the like. An object of the present invention is to provide a thermal overload relay which prevents the relay from coming off. A second object of the present invention is to provide a thermal overload relay in which a structure for preventing the adjusting screw of the current adjusting unit from being loosened has a simplified structure and a reduced cost by reducing the number of parts. The third purpose is
When the reset button is pressed, the reset button does not lock unless it is turned consciously in the lock direction, and there is no inconvenience that the lock is easily applied due to the delicate movement of the operated finger. It is to provide a relay.

[0011]

Means of the present invention taken to achieve the above object are as follows. In the first invention, an output contact mechanism and an overcurrent detection unit are provided in the case, and the output contact mechanism includes an auxiliary b contact and an auxiliary a contact having fixed contact and movable contact; A contact opening and closing member for opening and closing the auxiliary b contact and the auxiliary a contact by moving the movable contact, and an adjustment lever for adjusting the operation sensitivity of the contact opening and closing member by swing adjustment; The overcurrent detection unit includes a bimetal that is deformed when an overcurrent flows through the main circuit, and an interlocking unit that operates the contact opening / closing member by the displacement of the bimetal. A thermal overload relay for opening and closing the auxiliary b contact and the auxiliary a contact by operating the contact opening / closing member, wherein the adjustment lever has a shaft hole at two positions on a coaxial line. The write side shaft hole on the opposite side part of which is cut-out,
The width of the cutout portion is set wider than the thickness of the connecting portion that attaches the shaft member to the case, the shaft member is provided in the case in the mounting direction, and shafts are provided at both ends. The intermediate portion of the shaft member is attached to the case by the connection portion, and the adjustment lever is mounted on the shaft member so that the two shaft holes are positioned on both shafts of the shaft member so as to be swingably adjustable. A thermal overload relay characterized in that:

In the second invention, an output contact mechanism and an overcurrent detection section are provided in the case, and the output contact mechanism has an auxiliary b contact having a fixed contact and a movable contact and an auxiliary a contact. A contact opening and closing member for opening and closing the auxiliary b contact and the auxiliary a contact by moving the contact and the movable contact;
An adjustment lever for adjusting the operation sensitivity of the contact opening / closing member by swing adjustment, and a current adjustment unit having a means for adjusting the swing angle of the adjustment lever. A bimetal that is deformed when an overcurrent flows in the circuit, and an interlocking means for operating the contact opening / closing member by displacement of the bimetal,
A thermal overload relay that opens and closes the auxiliary b contact and the auxiliary a contact by operating the contact opening / closing member by the displacement of the bimetal, and adjusts a swing angle to one end of the adjustment lever. An adjusting screw having a tip abutting on the peripheral surface of the adjusting cam constituting the means for screwing is provided by screwing into the screw hole, and the adjusting screw or the surface of the screw hole is provided with a means for preventing loosening of the adjusting screw. A thermal overload relay characterized in that it is used.

According to a third aspect of the present invention, an output contact mechanism and an overcurrent detector are provided in the case, and the output contact mechanism includes an auxiliary b contact having a fixed contact and a movable contact, and an auxiliary a contact. A contact opening and closing member for opening and closing the auxiliary b contact and the auxiliary a contact by moving the contact and the movable contact;
A reset unit for returning the contact opening / closing member after the operation, wherein the overcurrent detection unit is configured to deform when an overcurrent flows in the main circuit, and the contact is caused by displacement of the bimetal. Interlocking means for operating the opening / closing member, wherein the contact opening / closing member is operated by the displacement of the bimetal which is deformed when an overcurrent flows in the main circuit, whereby the auxiliary b contact and the auxiliary a
A thermal overload relay for opening and closing contacts, wherein the reset unit is provided on the reset button so as to be able to be pushed into the case and to be rotatable in the circumferential direction of the shaft. A thermal overload relay, comprising: a pressing member for returning a member; and a means for providing resistance when rotating the reset button in a circumferential direction of the shaft.

(Action) In the thermal overload relay including the adjusting lever support structure according to the present invention, the shaft hole provided on the adjusting lever on the side opposite to the mounting side is the same as the mounting side of the shaft member. In the swinging position where the notch of the shaft hole does not fit with the connecting part when the back cover is removed during manufacturing or maintenance, the shaft hole is located at the end of the connecting part. Since the edge is hooked, it does not easily come off to the built-in side. Therefore, it is possible to prevent the adjustment lever from easily coming off the shaft member due to a slight impact or the like in the state described above.

In the thermal overload relay including the structure of the current adjusting section according to the present invention, the adjusting screw provided on the upper side of the adjusting lever or the loosening of the adjusting screw on the surface of the screw hole is provided. Since the stopping means is provided, the pressing piece as in the conventional structure is not required. Therefore, in the structure for preventing the adjusting screw of the current adjusting unit from being loosened, the number of components can be reduced, and the structure can be simplified and the cost can be reduced. Means for making the adjustment screw difficult to rotate is not particularly limited, but there is a method of applying or coating various materials for increasing frictional resistance, such as a metal screw or a resin having flexibility on the surface of the screw hole. Further, the adjusting screw itself can be formed of various materials that increase the frictional resistance.

The thermal overload relay including the structure of the reset section according to the present invention has a means for giving resistance when the reset button is rotated in the circumferential direction. When the button is pressed, the reset button does not lock unless it is turned consciously in the locking direction. Therefore, there is no inconvenience that the lock is easily applied due to the subtle movement of the finger to be operated, and there is no needless labor for releasing the lock. Means for giving resistance when the reset button is rotated in the circumferential direction of the shaft is not particularly limited. For example, a structure in which the members are brought into contact with each other against elasticity to obtain frictional resistance, a spring or the like may be provided. This is a structure in which resistance is obtained by the urging force of the force.

[0017]

Embodiments of the present invention will be described in more detail with reference to the drawings. FIG. 1 shows an embodiment of a thermal overload relay according to the present invention, in which a back cover is removed, FIG. 2 is a schematic sectional view taken along the line AA in FIG. 1, FIG.
FIG. 4 is a schematic cross-sectional view taken along the line BB in FIG. 1, FIG. 4 is an explanatory view of a main part showing an assembled state of a contact portion, FIG. FIG. 7 is an exploded perspective view showing the operation relationship between the operating lever and the operating rod, and FIG. 7 is an exploded perspective view showing the support structure of the adjusting lever. FIG. 8 shows the structure of the reset unit. (B) shows a state in which the operating rod is reset by pushing down, (c) is a sectional explanatory view of a main part showing a state in which it is turned and locked, and FIG. 9 is FIG.
(A) corresponds to FIG. 8 (b).
(B) is a bottom view explanatory view corresponding to FIG. 8 (c).

Reference numeral R denotes a thermal overload relay, which has a case 1 formed of insulating plastic. Inside the case 1, an output contact mechanism 2 and an overcurrent detection unit 3 as a main circuit connection unit are arranged in parallel. The overcurrent detection unit 3
It is provided on one upper side of the case 1 and has connection terminals 30, 31, and 32 for connecting to a main circuit (not shown). Inside the case 1, there are provided bimetals 33, 34, 35 connected to the connection terminals 30, 31, 32, respectively. A heating wire 36 heated by a current flowing through the main circuit is wound around the bimetals 33, 34, 35, respectively.

A slide plate 37 made of an insulator is accommodated in the lower portion of the case 1.
The distal end portions 4 and 35 are configured to engage with three portions of the slide plate 37. The tip of the slide plate 37 is in contact with the lower end of the interlocking plate 8 described later, and the interlocking plate 8 can be moved by bending deformation due to heating of the bimetals 33, 34, and 35.

The output contact mechanism 2 is movable contact between the auxiliary b contact 4 and the auxiliary a contact 5 by reciprocatingly swinging with the auxiliary b contact 4 and the auxiliary a contact 5 arranged at two places in the case 1. The operation rod 6 is a contact opening / closing member for opening and closing the contact by moving the operation lever, the operation assisting mechanism 7 for assisting the operation rod 6 to invert and swing, and the operation assisting mechanism 7 for moving the slide plate 37. An interlocking plate 8 for transmitting the operating rod 6 to the operating rod 6 via the operating rod 6 and a reset button 9 for manually returning the operating rod 6 and the auxiliary b contact 4 and the auxiliary a contact 5 to the state before the operation.

Here, the auxiliary b contact 4a and the auxiliary a contact 5
a will be briefly described. First, in the state where the auxiliary b contact 4a is closed, the self-holding circuit is closed and the electric device such as the electric motor is in the operating state, and since the auxiliary a contact 5a is open, no alarm is displayed. Then, when an overcurrent flows through the operating electric device and the auxiliary b contact 4a opens, the self-holding circuit opens and the electric device stops. At the same time, the auxiliary a contact 5a is closed and an alarm display such as an alarm lamp is displayed.

The auxiliary b contact 4 is provided on the upper side inside the case 1. The auxiliary b contact 4 has a fixed contact 40 and a movable contact 44. The fixed contact 40 includes a short-circuit fitting 42 connected to a terminal fitting 41 outside the case 1, and a fixed contact 43 is provided at an end of the short-circuit fitting 42. The movable contact 44 includes a short-circuit fitting 46 connected to a terminal fitting 45 outside the case 1. A movable contact plate 47 having a required spring force is fixed to the inclined portion of the chevron portion of the short-circuiting member 46 with its upper end fixed.

The movable contact plate 47 is bent at an obtuse angle at a substantially middle portion to form a "<" shape, and a movable contact plate is provided near the bent base portion on the front side which is substantially vertical. 48 are provided. In the above-mentioned assembled state, the fixed contact 43 of the fixed contact 40 and the movable contact 48 of the movable contact 44 are in contact with each other, but the movable contact plate 47 is hardly bent, and the load due to the bending is only about several g. I'm trying to avoid it.

The auxiliary a contact 5 is provided on the lower side of the case 1 and has the same structure as the auxiliary b contact 4. That is, the auxiliary a contact 5 has a fixed contact 50 and a movable contact 54. The fixed contact 50 includes a short-circuit metal fitting 52 connected to a terminal metal fitting 51 outside the case 1, and a fixed contact 53 is provided at an end of the short-circuit metal fitting 52. The movable contact 54 has a short-circuiting metal fitting 56 connected to a terminal metal fitting 55 outside the case 1. A movable contact plate 57 having a required spring force is attached to the inclined portion of the chevron portion of the short-circuit fitting 56 with its upper end fixed.

The movable contact plate 57 is bent at an obtuse angle at a substantially middle portion and is formed in the shape of a "<", and a movable contact plate is provided near the bent base portion on the front side which is substantially vertical. 58 are provided. Although the fixed contact 53 of the fixed contact 50 and the movable contact 58 of the movable contact 54 are in contact with each other, the movable contact plate 5
7 is not bent so that a load due to bending is not applied.

The operating rod 6 is disposed closer to the back opening of the case 1 than the auxiliary b contact 4 and the auxiliary a contact 5 are. The operating rod 6 is made of insulating plastic and has a rod 60 of a required length. A swing center shaft 61 is provided at a substantially intermediate portion of the rod 60 so as to protrude in the front direction of the case 1, and the operating rod 6 connects the swing center shaft 61 to the bearing 11 of the case 1.
Can be rotated by inserting it into

At the upper end of the rod 60, the operating rod 6
A display unit 62 for displaying that the operation has been performed is provided so as to protrude in the same direction as the swing center axis 61 (see FIG. 2).
In the rod 60, a separating member 63 and a pressing member 64 are provided at an intermediate portion between the display portion 62 and the swing center shaft 61 so as to protrude in the same direction.

The separating member 63 is located on the left side of the movable contact plate 47 of the auxiliary b contact 4 and the movable contact 48 in FIGS.
It is located on the lower side and deflects the movable contact plate 47 in a direction away from the fixed contact 40 during operation. 5 and 6, the pressing member 64 is located on the right side of the movable contact plate 47 and on the back side of the movable contact 48. In a state before the operation, a tension spring 74 of the operation assisting mechanism 7 described later is used. The movable contact 48 is fixed to the fixed contact 43 by the spring force of
Press on the side.

At the lower end of the rod 60, a separating member 65 and a pressing member 66 are provided which protrude in the same direction at predetermined intervals in the vertical direction. The separating member 65 is located on the left side of the movable contact plate 57 of the auxiliary a contact 5 and below the movable contact 58 in FIGS.
The movable contact plate 57 is bent in a direction away from the fixed contact 50. 5 and 6, the pressing member 66 is located on the right side and at the tip of the movable contact plate 57.
During operation, the distal end side of the movable contact plate 57 is bent by the spring force of a tension spring 74 of the operation assisting mechanism 7 described later, and the movable contact 58 is pressed against the fixed contact 53.

In the rod 60, a reset arm 67 protruding leftward in an "L" shape is provided near the separating member 63 and the pressing member 64. Reset arm 67
Is located below a reset button 9 to be described later, and serves as a hook for returning the operating rod 6 to a state before the operation by pressing the reset button 9.

The operation assisting mechanism 7 utilizes a toggle mechanism. The inversion of the reversing plate 73 attached to the operating rod 6, that is, the inversion of the operating rod 6 is instantaneous from the dead center of the middle part. (See FIGS. 1 and 3). The operation assisting mechanism 7 includes a receiving member 70 fixed to the case 1.
A “V” -shaped concave portion 71 is provided at an upper portion of the receiving member 70, and a hanging member 72 is provided at a lower portion thereof so as to protrude.

A reversing moving portion of a reversing plate 73 is inserted and fixed to the operating rod 6 above the swing center shaft 61. The reversing plate 73 has a substantially “U” shape, and the lower part of both ends is formed with the receiving member 70.
And can swing about the lower ends at both ends on the receiving member 70. The upper end of a tension spring 74 is hung on the upper part of the reversing plate 73. A lower end of a link plate 75 is rotatably hung on the hook member 72 of the receiving member 70. The lower end of the extension spring 74 is provided with a link plate 75.
It is hung on the upper end. With this structure, the tension spring 74 and the link plate 75 are normally linear due to the spring force of the tension spring 74, and maintain the reversing plate 73 in a state of being inclined left or right.

The interlocking plate 8 is arranged near the left side of the operation assisting mechanism 7. The interlocking plate 8 is formed in a substantially “U” shape, and is attached to the adjustment lever 80 so as to be rotatably engaged in the vicinity of the bent portion. The lower end of the interlocking plate 8 is in contact with the tip of the slide plate 37, and the upper end is in contact with the upper surface of the link plate 75.

The adjusting lever 80 is pivotally mounted by fitting shaft holes 81 and 82 provided at two places on the coaxial line in the middle part into the shaft member 12 provided in the case 1 (FIG. 1). 7). The shaft hole 82 on the opposite side of the adjustment lever 80 from the installation side is partially cut out to provide a cutout portion 820. The width of the notch 820 is determined by adjusting the shaft member 12 to the case 1.
Is set to be slightly wider than the thickness of the connecting portion 120 attached to. The shaft member 12 is provided in the case 1 in the assembling direction, the intermediate portion is attached to the case 1 by a connecting portion 120, and shafts 121 and 122 are provided on both ends.
Then, the adjusting lever 80 has the shaft holes 81 and 82 formed in the shaft member 1.
It is mounted on the second shafts 121 and 122 so as to be swingable.

A switch knob 83 is provided at the upper end of the adjustment lever 80 so as to pass through a slide groove (not shown) on the upper surface of the case 1. In the vicinity of the switch knob 83, an adjustment screw 84 is screwed through a screw hole (not shown). The surface of the screw portion of the adjusting screw 84 is coated with a flexible resin. As a result, the frictional force with the screw hole becomes large and it becomes difficult to rotate, so that the adjusting screw 84 can be prevented from loosening. In addition,
The adjusting screw 84 is rotated through an operation hole 13 provided on a side portion of the case 1 so that access can be adjusted. Further, the switch knob 83 is used for manually setting the operation state at the time of performing a test or the like, and the adjustment screw 84 is provided between the upper part of the adjustment lever 80 and the adjustment cam 140 described below.
This is for adjusting the sensitivity of the operation of the operating rod 6 by adjusting the set interval between the two.

A current adjusting dial 14 is rotatably mounted on the upper part of the case 1 in correspondence with the position of the adjusting screw 84. An adjustment cam 140 is provided inside the case 1 of the current adjustment dial 14. Adjustment cam 140
Is formed such that the distance from the rotation center to the peripheral surface changes continuously. The current adjustment dial 14 can rotate the adjustment lever 80 by rotating the adjustment lever 84 by bringing the tip of the adjustment screw 84 into contact with the peripheral surface of the adjustment cam 140 to change the swing width. Thereby, the interlocking plate 8 is separated or approached from the slide plate 37 to adjust the amount of displacement transmitted by the bending of the bimetals 33, 34, 35, and to adjust the operation sensitivity to the current supplied to the main circuit. Things.

The structure of the reset unit will be described mainly with reference to FIGS. In FIG. 8, the operating rod 6 is not shown. The reset button 9 is provided through the upper portion of the case 1 above the operating rod 6 as described above, and a pressing member 90 and a locking member 91 are provided inside the case 1. The reset button 9 is urged by a return spring 92 and is always pushed upward. When the reset button 9 is pushed downward, the pushing member 90 pushes the reset arm 67 of the operating rod 6 in the returning direction. (From FIG. 8 (a) to (b)
State), the reversing plate 73 exceeds the dead center, whereby the operating rod 6 after the operation can be returned to the state before the operation.

The reset button 9 is rotated in the clockwise direction in the depressed state (FIGS. 8B to 8C and FIG. 9B).
(A) to (B)), the locking portion 910 provided at the front end of the locking member 91 can be locked by locking to the locking receiving portion 15 provided on the inner surface of the case 1. it can. When the reset button 9 is rotated, the locking member 91 comes into contact with the obstacle projection 16 provided on the inner wall portion of the case 1 and is deformed inward against its elasticity. A relatively large rotational resistance is generated by the frictional resistance between the locking member 91 and the obstacle projection 16. Therefore, the reset button 9 does not lock unless it is consciously turned in the locking direction, and it is possible to prevent the lock from being easily applied due to the delicate movement of the operated finger when it is not necessary to lock.

(Operation) The operation of the thermal overload relay R according to the present invention will be described with reference to FIGS. (Before Actuation) In a state before actuation (see FIGS. 1 and 5), the reversing plate 73 of the actuation assisting mechanism 7 is tilted to the left in the figure, and the actuation rod 6 is also turned in the counterclockwise direction. ing. The upper end of the interlocking plate 8 is in contact with the upper part of the link plate 75, and the lower end is in contact with the left end of the slide plate 37. As a result, the movable contact 48 of the auxiliary b contact 4 on the upper side is fixed to the fixed contact 43 by the pressing member 64 by the action of the spring force of the tension spring 74 of the operation assisting mechanism 7.
And a sufficient contact load between the fixed contact 43 and the movable contact 48 is ensured. Further, the movable contact plate 57 of the lower auxiliary contact 5 is bent by the separating member 65 in a direction away from the fixed contact 50, and the fixed contact 53 and the movable contact 58 are open.

(During operation) When an overcurrent of a predetermined value or more flows through the main circuit, the bimetals 33, 34, and 35 are heated, and bend leftward in FIG. As a result, the slide plate 37 is pushed leftward, and the slide plate 37 rotates the interlocking plate 8 clockwise. By the rotation of the interlocking plate 8,
The link plate 75 is pushed rightward, and accordingly, the reversing plate 7
3 rotates rightward, and falls rightward instantaneously by the action of the tension spring 74 when the dead center is exceeded. Then, the operating rod 6 integrated with the reversing plate 73 also simultaneously rotates in the clockwise direction at this time. When the operating rod 6 rotates clockwise, the separating member 63 pushes the movable contact plate 47 of the auxiliary b contact 4 to bend, and the fixed contact 43 and the movable contact 48
And open the contacts.

In the auxiliary contact 5, the movable contact plate 57 is bent leftward in FIG. 6 by the pressing member 66 of the operating rod 6, and the movable contact 58 is
Of the fixed contact 5 by the action of the spring force of the tension spring 74 of FIG.
3 and a sufficient contact load between the fixed contact 53 and the movable contact 58 is ensured. At this time, the movable contact point 58 is located at an intermediate portion between two points of action (a bent portion of the movable contact plate 57 and an abutting portion of the pressing member 66) of a force serving as a contact pressure. The load due to the beam,
A relatively large load can be obtained even with a small amount of bending.

The repulsive load of the movable contact plate 47 when the separating member 63 pushes the movable contact plate 47 is at least a contact load between the contacts as compared with the conventional movable contact by self-contact. Since it becomes smaller by the amount that the bending force does not act, the operation of the operating rod 6 at the time of operation is stabilized.

(After Operation) After the operation of the thermal overload relay R, when resetting after the bending of the bimetals 33, 34, 35 is restored, the reset button 9 is pushed in as described above, and the operating rod 6 is pushed. The operation rod 6, the auxiliary b contact 4, the auxiliary a contact 5,
The interlocking plate 8 and the slide plate 37 can be returned to the state before the operation. In order to lock the reset button 9 in the pressed state, it is only necessary to turn the reset button 9 in the clockwise direction.
, The rotational resistance is obtained by both frictional resistances. Therefore, when the reset button 9 is pressed, the reset button 9 does not lock unless it is turned intentionally in the locking direction. Therefore, unlike the conventional type, there is no inconvenience that the reset button 9 is easily locked by the delicate movement of the finger to be operated, and there is no needless labor for releasing the lock.

In order to adjust the operation sensitivity of the thermal overload relay R with respect to the current flowing through the main circuit, the following operation is performed. First, when increasing the set value of the current for operating the thermal overload relay R, the current adjustment dial 14 is turned,
Adjust the adjustment lever 80 in the clockwise direction to adjust the adjustment lever 80.
The lower side of the to the left to move the interlocking plate 8 to the bimetal 33,
34 and 35. As a result, the force cannot be transmitted by the slide plate 37 unless the bimetals 33, 34, 35 are deformed more by a larger current. In order to reduce the set value of the current, on the contrary, the current adjustment dial 14 is turned, the adjustment lever 80 is adjusted to the left rotation direction, and the lower side of the adjustment lever 80 may be shifted to the right. Further, the adjusting screw 84 abutting on the peripheral surface of the adjusting cam 140 which rotates together with the current adjusting dial 14.
Since the surface of the screw portion is coated with the resin having flexibility as described above, the frictional force with the screw hole is increased, the adjusting screw 84 is hardly loosened, and a pressing piece as in the conventional structure is provided. It is not necessary.

Further, in a state where the back cover is removed at the time of manufacturing or maintenance, the shaft hole 82 on the opposite side to the installation side is formed.
In the swinging position where the notch portion 820 does not fit with the connecting portion 120, the edge of the shaft hole 82 is hooked on the end of the connecting portion 120, so that it does not easily come off to the installation side. Therefore, in the above-described state, the adjustment lever 80 can be prevented from easily coming off the shaft member 12 due to a slight impact or the like, and workability during manufacturing or maintenance is improved.

The terms and expressions used in the present specification are merely illustrative and not restrictive, and do not exclude the terms and expressions equivalent to the above terms and expressions. Further, the present invention is not limited to the illustrated embodiment, and various modifications can be made within the scope of the technical idea.

[0047]

The present invention has the above configuration and has the following effects. (A) In the thermal overload relay including the support structure for the adjustment lever according to the present invention, the shaft hole provided on the adjustment lever on the side opposite to the installation side is the same as the shaft member on the side opposite to the installation side. In the swinging position where the notch of the shaft hole does not match with the connecting part when the back cover is removed during manufacturing and maintenance, the edge of the shaft hole is located at the end of the connecting part. Since it is caught, it does not come off easily to the built-in side. Therefore, it is possible to prevent the adjustment lever from easily coming off the shaft member due to a slight impact or the like in the state described above.

(B) In the thermal overload relay including the structure of the current adjusting section according to the present invention, the adjustment is made on the surface of the adjusting screw or screw hole screwed on the upper side of the adjusting lever. Since the means for preventing the screw from turning is provided, the adjusting screw is hard to be loosened, and the pressing piece as in the conventional structure is not required. Therefore, in the structure for preventing the adjusting screw of the current adjusting unit from being loosened, the number of components can be reduced, and the structure can be simplified and the cost can be reduced.

(C) The thermal overload relay including the structure of the reset section according to the present invention has a means for giving resistance when the reset button is rotated in the axial direction. When the reset button is pressed, the reset button does not lock unless it is turned intentionally in the lock direction. Therefore,
There is no inconvenience that the lock is easily applied due to the delicate movement of the operated finger, and there is no needless work for releasing the lock.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a thermal overload relay according to the present invention, with a back cover removed.

FIG. 2 is a schematic sectional view taken along the line AA in FIG.

FIG. 3 is a schematic sectional view taken along line BB in FIG. 1;

FIG. 4 is an explanatory view of a main part showing a state where the contact portion is assembled.

FIG. 5 is an explanatory view showing an operation relationship between a contact portion and an operation rod in a return state.

FIG. 6 is an explanatory diagram showing an operation relationship between a contact portion and an operation rod and showing an operation state;

FIG. 7 is an exploded perspective view showing a support structure of an adjustment lever.

FIGS. 8A and 8B show the structure of a reset section, wherein FIG. 8A shows an initial state, FIG. 8B shows a state in which the operating rod is reset by pushing down, and FIG. FIG.

9A and 9B are explanatory views in a bottom view of FIG. 8, in which FIG. 9A corresponds to FIG. 8B and FIG. 9B is an explanatory view in a bottom view corresponding to FIG.

FIG. 10 is an explanatory view showing a structure of a conventional thermal overload relay, with a back cover removed.

FIG. 11 is an exploded perspective view showing a conventional adjustment lever support structure.

12A and 12B show the structure of a conventional reset unit, where FIG. 12A shows an initial state, FIG. 12B shows a state in which the operating rod is reset by pushing down, and FIG. FIG.

[Description of Signs] R Thermal Overload Relay 1 Case 11 Bearing 12 Shaft Member 120 Connection 121, 122 Shaft 13 Operation Hole 14 Current Adjustment Dial 140 Adjustment Cam 15 Locking Receptor 16 Fault Protrusion 2 Output Contact Mechanism 3 Overcurrent detection unit 30, 31, 32 Connection terminal 33, 34, 35 Bimetal 36 Heating wire 37 Slide plate 4 Auxiliary b contact 40 Fixed contact 41 Terminal fitting 42 Shorting fitting 43 Fixed contact 44 Movable contact 45 Terminal fitting 46 Shorting fitting 47 Movable contact plate 48 Movable contact 5 Auxiliary a contact 50 Fixed contact 51 Terminal fitting 52 Shorting fitting 53 Fixed contact 54 Movable contact 55 Terminal fitting 56 Shorting fitting 57 Movable contact plate 58 Movable contact 6 Operating rod 60 Rod 61 Swing center axis 62 Display Part 63 separation member 64 pressing member 65 separation member 66 pressing member 67 reset Arm 7 Actuation assisting mechanism 70 Receiving member 71 Recess 72 Retaining member 73 Reversing plate 74 Tension spring 75 Link plate 8 Interlocking plate 80 Adjusting lever 81, 82 Shaft hole 820 Notch 83 Switch knob 84 Adjusting screw 9 Reset button 90 Depressing member 91 Locking member 910 Locking portion 92 Return spring

Claims (3)

[Claims] An output contact mechanism (2) and an overcurrent detector (3) are provided in a case (1), and the output contact mechanism (2) is provided with fixed contacts (40, 50). Auxiliary b-contact with movable contacts (44,54)
A contact opening / closing member for opening and closing the auxiliary b contact (4) and the auxiliary a contact (5) by moving the movable contact (44, 54) and the auxiliary a contact (5); An adjustment lever (80) for adjusting the operation sensitivity of the contact opening / closing member by adjustment.The overcurrent detection unit (3) is provided with a bimetal ( 33,
34, 35), and interlocking means for operating the contact opening / closing member by the displacement of the bimetal (33, 34, 35), and the contact by the displacement of the bimetal (33, 34, 35). A thermal overload relay that opens and closes the auxiliary b contact (4) and the auxiliary a contact (5) by operating an opening / closing member, wherein the adjusting lever (80) has two axial holes on a coaxial line. (81,82)
The shaft hole (82) on the side opposite to the built-in side is partially notched, and the width of the notch (820) is the coupling that attaches the shaft member (12) to the case (1). The thickness is set to be wider than the thickness of the part (120), the shaft member (12) is provided in the case (1) in the mounting direction, and shafts (121, 122) are provided at both ends, and the shaft member ( The intermediate portion of (12) is attached to the case (1) by the connecting portion (120), and the adjusting lever (80) has the two shaft holes (81, 82) in both shafts (81, 82) of the shaft member (12). (121, 122), mounted on the shaft member (12) so as to be swingably adjustable. 2. An output contact mechanism section (2) and an overcurrent detection section (3) are provided in a case (1). The output contact mechanism section (2) has fixed contacts (40, 50). Auxiliary b-contact with movable contacts (44,54)
A contact opening / closing member for opening and closing the auxiliary b contact (4) and the auxiliary a contact (5) by moving the movable contact (44, 54) and the auxiliary a contact (5); An adjustment lever (80) for adjusting the operation sensitivity of the contact opening / closing member by adjustment, and a current adjustment unit having a means for adjusting a swing angle of the adjustment lever (80). The part (3) is a bimetal (33,
34, 35), and interlocking means for operating the contact opening / closing member by the displacement of the bimetal (33, 34, 35), and the contact by the displacement of the bimetal (33, 34, 35). A thermal overload relay that opens and closes the auxiliary b contact (4) and the auxiliary a contact (5) by operating an opening / closing member, wherein one end of the adjustment lever (80) has a swing angle. An adjusting screw (84) whose leading end abuts on a peripheral surface of an adjusting cam (140) constituting a means for adjusting the diameter of the adjusting screw (84) is screwed into a screw hole, and the adjusting screw (84) or the surface of the screw hole is provided. The thermal overload relay according to claim 1, further comprising means for preventing the adjusting screw (84) from being loosened. 3. An output contact mechanism section (2) and an overcurrent detection section (3) are provided in a case (1), and the output contact mechanism section (2) is provided with fixed contacts (40, 50). Auxiliary b-contact with movable contacts (44,54)
(4) and an auxiliary a contact (5); a contact opening / closing member for opening and closing the auxiliary b contact (4) and the auxiliary a contact (5) by moving the movable contact (44, 54); A reset unit for returning the contact opening / closing member of the contactor.The overcurrent detection unit (3) includes a bimetal (33,
34, 35) and interlocking means for operating the contact opening and closing member by the displacement of the bimetal (33, 34, 35), and the bimetal ( 33,
A thermal overload relay that opens and closes the auxiliary b-contact (4) and the auxiliary a-contact (5) by activating the contact opening and closing member by the displacement of (34, 35); A reset button (9) provided to be able to be pushed into the case (1) and rotatable in the axial direction, and a pressing member (90) provided on the reset button (9) for returning the contact opening / closing member. And a means for giving a resistance when the reset button (9) is rotated in the circumferential direction of the shaft.