JPH063700B2 - Leaf switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Object of the Invention" The present invention relates to a leaf switch operated by a plunger.

"Conventional Switch and its Problems" Conventionally, this type of switch is provided with a movable piece 26 having a movable contact 34 between a pair of fixed contacts 33 and 53 as shown in FIG. The plunger 61 presses against the elasticity of the movable piece to switch from one fixed contact 33 to the other fixed contact 53;
As shown in the figure, the first fixed contact 33 and the second fixed contact 5
A third movable piece 46 having a contact 34 that is in constant contact with the first fixed contact 33, and a second contact 54 that is open with respect to the second fixed contact 53 between the three.
And a plunger 61 is engaged with the free ends of the movable pieces so as to maintain the movable pieces at a predetermined distance.
By operating this plunger, each movable contact 3
There is one that opens and closes the first and second fixed contacts 33 and 53, respectively.

However, since the movable contacts 34, 54 are mounted by caulking near the free ends of the movable pieces 26, 46 formed by a single strip, the movable contacts 26, 46 can be attached from the attachment points of the movable contacts 34, 54. The part between the free ends is not collinear with the part between the movable contacts 34, 54 and the fulcrum of the movable pieces 26, 46, that is, each movable piece has a different angle. There is. In other words, with respect to the fixed contacts 33 and 53 that should be paired, the movable piece 26,
The portions of the movable contacts 34, 54 on the free end side are inclined toward or away from each other. Therefore, in the case where the plunger 61 is in direct contact with the movable pieces 26 and 46, the contact pressures of the movable contacts 34 and 54 against the fixed contacts 33 and 53 vary, and in particular, the switching located on the upper side in FIG. In the case of the movable contact 34, which is always pressed in the closing direction by the element 41, i.e. the plunger 61, this results in less precision.
Further, in the case of the normally open type switching element 51 such as the switching element 51 located on the lower side of FIG. 6, the movable piece 46 is pressed by the plunger 61, and the second movable contact 54 becomes the second fixed contact 53. If the plunger 61 is further pressed in the state of being in contact with, the stress may be applied to the portion of the movable piece 46 in contact with the movable contact 54 and the support point of the movable piece 46, and the movable piece 46 may be broken. In order to prevent this, it is necessary to reduce the amount of movement of the plunger 61, but this not only results in a switch that is difficult to use in operation, but also the movable contact 5
Since it is necessary to reduce the gap between the No. 4 and the fixed contact 53, the insulation performance deteriorates, and the operating position is inaccurate.
Moreover, since the displacement amount of the movable piece 46 is naturally limited,
There is a drawback in that the switch operation, especially the movement after the closing operation, that is, the overtravel cannot be sufficiently obtained and the desired contact pressure cannot be obtained.

Further, in general, a cantilevered movable piece needs to simultaneously satisfy the two contradictory conditions of stress fatigue and contact pressure.

Now, the state shown by the dotted line in FIG. 7 is set to the free state, and when the external force F is applied to the free end in this state, the movable piece 26 becomes the state shown by the solid line. The force F at this time is Becomes Here, E is Young's modulus, I is the second moment of area, and y is the gap between the contacts.

The bending stress S is Becomes Here, Z is a section modulus. I and Z are constants determined by the plate thickness and width of the movable piece.

That is, as the contact pressure, which substantially corresponds to the force F, increases, the stress S also increases, so that the movable piece 26 is easily fatigued and easily broken.

Especially for small leaf switches, movable piece 2
Since the effective length 1 of 6 is limited, there is a drawback that it is difficult to reduce the stress of the movable piece 26 and increase the contact pressure.

In the conventional leaf switch, the contact gap is unstable because there is no stopper that restricts the movement of the movable pieces when the movable pieces 26 and 46 are in the open state, and the vertical movement of the movable pieces is large. Has a drawback that it becomes large and the life is shortened.

On the other hand, as shown in FIG. 6, two sets of switching elements 41,
For those having 51, since those switching elements are provided in the same room, the arc powder of one switching element adheres to the contact point of the other switching element, causing poor continuity or broken movable piece. There is a risk of short-circuiting with the other side.

"Purpose" In view of such conventional drawbacks, the present invention has an object to obtain a leaf switch in which the stress of the movable piece is small and the operation is reliable.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIGS. 1 to 4, the housing 1 is formed in a substantially rectangular shape, and the support wall 3 that is substantially parallel to the first side wall 1a is provided on one end side thereof on the longitudinal axis thereof.
The second side wall 1b and the guide wall 4 which are substantially parallel to each other are integrally formed on the other end side of the second side wall 1b at predetermined intervals. A guide groove 5 is formed between them by the wall. In addition, a partition wall 6 is provided in the housing 1 along the longitudinal axis thereof.
Are integrally formed so as to project from the bottom wall thereof, and the partition wall divides the housing 1 into two chambers, that is, a first chamber 7 and a second chamber 8. The partition wall 6 is transformed at one end thereof into a reinforcing portion 11 which connects the first side wall 1a of the housing 1 and the support wall 3 with each other, and a mounting screw (not shown) is provided at an intermediate portion of the partition wall. A cylindrical portion 14 having a through hole 12 penetrating therethrough is formed, and an insulating contact portion (hereinafter abbreviated as contact portion) 15 is formed on the other end side of the partition wall 6 so as to intersect with the partition wall. Accordingly, the movement of the free end of the first movable piece 26, which will be described later, is restricted within a predetermined range in the released state. Moreover, the reinforcing portion 11 is provided with a fitting hole 17 having a predetermined depth from the opening side of the housing 1 toward the bottom wall portion thereof, and the cylindrical portion 14 is concentric with the through hole 12 and penetrates the through hole 12. A circular fitting recess 19 having a larger diameter than the hole is formed from the opening side of the housing 1. On the first chamber 7 side, the first side wall 1a and the support wall 3 have a pair of fitting grooves 21 and 21 having a shorter dimension than the dimension between the end portion on the opening side of the housing 1 and the bottom wall portion 9 thereof. A pair of fitting grooves 22 that are the same as the fitting grooves 21 are provided in the first side wall 1a and the support wall 3 on the second chamber 8 side at a predetermined interval. Are provided symmetrically with respect to the longitudinal axis. Then, in the fitting groove 21 on the side of the first chamber 7, the third side wall 1 of the housing 1
The first fixing piece 25 is fitted in the fitting groove 21a near c. The fixing piece is formed of a strip-shaped single plate, and two pairs of convex portions 27 and 28 extending in the width direction are provided at one end side of the fixing piece at predetermined intervals. And fixed piece 2
The width b ₁ of the protrusions 28a and 28b in the axial direction of 5 is the first
Is equal to or slightly larger set interval b ₂ between the side walls 1a and the support wall 3 of, and mutually spacing b ₃ between adjacent convex portions 27 and 28 is larger than the thickness b ₄ of the first side wall 1a It is set. A pair of protrusions 29a, 29b extending in the width direction are provided on the other end side of the fixing piece 25, and one of the protrusions 29a protrudes on the bottom wall portion 9 in a state of being attached to the housing. It is configured to come into contact with the installed receiving portion 31. A circular fixed contact 33 is provided at the other end of the fixed piece 25. In the first chamber 7 of the housing 1, the other end of the fixing piece 25 is fixed to the third side wall 1c.
3 is provided with a protruding portion 32 that is received substantially on the axis.
Further, in the first chamber 7, the fitting groove 21 near the reinforcing portion 11
The first movable piece 26 is fitted in b. This movable piece is formed of an elastic strip-shaped plate, and one end of the movable piece is formed to have a thickness almost doubled by bending and stacking a plate body having a width of twice or more. Therefore, the thickness of the fixing piece 25 is substantially equal to that of the fixing piece 25. And in this doubled portion, the convex portion 37,
38 project from each other at a predetermined interval, and the width b ₅ of the convex portion 38 in the axial direction of the movable piece 26 is determined by the fixed piece 25.
If equal to the spacing b ₂ between the first side wall 1a like the convex portion 28a and the support wall 3 it is set slightly larger than the further distance b ₆ between the convex portions 37, 38 also adjacent the fixing pieces 25 The thickness of the first side wall 1a as well as the distance b ₃ between the protrusions 27a and 28a
Larger than b ₄ . The other end of the movable piece 26, that is, the free end, is provided with a movable contact 34 that selectively contacts the fixed contact 33, and this movable contact is formed in a circular shape like the fixed contact 33. The first movable piece 26 is urged so that its movable contact 34 is always separated from the fixed contact 33. That is, the first fixed piece 25 and the first movable piece 26 open and close the load having a relatively large capacity.
The switching element 41 is formed.

Further, the fitting groove 22b near the fourth side wall 1d of the housing 1
The second fixing piece 45 is fitted to the. This fixing piece is the first
The fixing piece 25 has the same shape as the fixing piece 25.

A fixed contact 53 having a mountain-shaped cross section and a linear shape is provided at the other end of the fixed piece 45 in a direction intersecting the axis of the fixed piece 45. In the second chamber 8 of the housing 1, the bottom wall 9 thereof has a convex portion 29a provided on the other end side of the second fixing piece 45.
A holding portion 43 having a groove 42 that receives the second holding piece 45 is provided so that the other end of the second fixing piece 45 is prevented from moving in the plate thickness direction. Further, the fourth side wall 1d of the housing 1 is provided with a protrusion 44 that receives the other end of the second fixed piece 45 substantially on the axis of the fixed contact 53. Second
The second movable piece 46 is fitted in the fitting groove 22 a near the reinforcing portion 11 in the chamber 8. This second movable piece is the first
The same material and structure as the movable piece 26 of FIG. However, the difference from the first movable piece 26 is that the dimension from the support wall 3 to the free end is longer than that of the first movable piece 26. Further, on the free end side of the second movable piece 46, a movable contact 54 extending in the axial direction, that is, intersecting with the fixed contact 53, and having a chevron cross section and a linear shape is provided like this fixed contact. . The second movable piece 46 has its movable contact 5
4 is always urged to contact the fixed contact 53. That is, the second fixed piece 45 and the second movable piece 4
A pair of crossed chevron contacts are formed at 6, and thereby a second switching element 51 for opening and closing a relatively small load is formed.

A prismatic plunger 61 is slidably accommodated in the guide groove 5, and one end of the plunger 61 penetrates the third side wall of the housing 1 and projects outward. On the other hand, a notch 10 having a predetermined length is provided in the middle of the guide wall 4. A notch 10 is formed in the middle of the plunger 61 to extend toward the inside of the housing 1, and the tip of the notch 10 is formed into a first portion.
The first operating element 62, which is a protrusion located on the axis of the movable contact 34 of the movable piece 26, is integrally provided. A second actuator 63, which is a recess having a predetermined dimension h ₂ in the axial direction, is provided near the other end of the plunger 61.
Is formed from the guide wall 4 side, and a mountain-shaped convex portion 64 is formed on the other end side. The free end of the second movable piece 46 extends into the second actuator 63, that is, the recess.
That is, while the distance from the support wall 3 of the first movable piece 26 to the first actuator 62 is l ₁ , the second movable piece 46 is
The distance from the support wall 3 to the second actuator, that is, the convex portion 64 is set to l ₂ . Plunger 61 is the first
Position, that is, when it is in the upper position as shown in FIG.
The first operating element 62 causes the movable contact 34 to directly contact the fixed contact 33 against the biasing force of the first movable piece 26 on this axis, and the convex portion 64 causes the movable contact 34 to move. 54 is moved away from the fixed contact 53 against the biasing force of the second movable piece 46, and its plunger is in the second position, i.e. in the lower position as shown in FIG. 2, the first actuation. The child 62 is separated from the first movable piece 26, that is, the movable contact 34 thereof, and separated from the first movable element 26.
The opening 64 is opened, the convex portion 64 is separated from the second movable piece 46, and the movable contact 54 is brought into contact with the fixed contact 53 by the biasing force of the movable piece 46 itself.

Further, the first actuator 62 and the second actuator 62 of the plunger 61
A slot 65 having a predetermined length h ₃ is provided along the axis of the surface adjacent to the surface on which the actuator 63 is provided, while the bottom wall portion of the guide groove 5 is provided with a slot. A convex portion 66 that slidably engages with 65 is provided. And slot 6
When one end of 5 collides with the convex portion 66, the plunger 61
Stop at the first position, and the other end of the long hole 65
6 is designed to stop the plunger 61 in the second position when it abuts.

A coil spring 71 is housed in the guide groove 5,
One end thereof has an engaging protrusion 6 provided at the other end of the plunger 61.
7, and the other end is in contact with the inner surface of the fourth side wall 1d of the housing 1. The coil spring has a much larger biasing force than the sum of the biasing forces of the first movable piece 26 and the second movable piece 46. Therefore, when the plunger 61 is in the non-operating state, the plunger is held in the first position, whereby the first switching element 41 has a normally closed contact and the second switching element 51 has a normally open contact. Each is formed.

In the operating state of the plunger 61, that is, in the second position, the first movable piece 26 is prevented by the contact portion 15 from moving too far toward the second switching element 51 side.

Further, on the axial center of the partition wall 6, the protruding wall 1 having a fitting hole 18 of the same shape as the fitting hole 17 is formed in the second side wall 1b of the housing 1.
6 is integrally formed. A through hole 13 having the same diameter as the through hole 12 is provided in a portion of the fourth side wall 1d of the housing 1 near the guide wall 4.

Protrusions 83 and 84 that fit into the fitting holes 17 and 18 are provided on one surface of the cover 81 that covers the opening of the housing 1, and the diameters of these protrusions are the inner diameters of the fitting holes 17 and 18. Is set to be the same as or slightly larger than. Further, the cover 81 has through holes 85, 86 corresponding to the through holes 12, 13.
Is provided. The cylindrical portion 8 that fits into the fitting recess 19 provided in the housing 1 is provided at the hole edge portion of the one through hole 85.
7 is integrally molded. Also, on one surface of the cover 81, when the cover is attached to the housing 1,
Plunger 61 is provided between the housing and the bottom wall.
A ridge 88 for slidably guiding the movable pieces 26, 46 in the width direction of the fixed pieces 25, 45 and the movable pieces 26, 46 in the portions corresponding to the first side wall 1a and the support wall 3 of the housing 1. Projecting walls 89, 89 that abut against the other edge are formed, and a tapered guide projection 90 that guides the lower end of the spring 71 is provided at a portion corresponding to the lower end of the guide groove 5 of the housing 1. There is.

"Operation" As shown in FIG. 1, the plunger 61 is at the first position, that is, at the upper side, and the convex portion 66 is at one end of the elongated hole 65, that is, near the lower end. Therefore, the movable contact 34 is in contact with the fixed contact 33 by the first operating element 62 located immediately below the movable contact 34. Therefore, the first switching element 4
1 is in the closed state. At the same time, the movable contact 54 has a convex portion 64.
Therefore, the second switching element 51 is in an open state because it is separated from the fixed contact 53.

Then, when the plunger 61 is pressed and moved to the second position, that is, downward as shown in FIG. 2, the convex portion 66 abuts against the other end of the slot 65, that is, the upper end, and therefore the first actuator 62. Separates from the movable contact 34 and releases the first movable piece 26. Therefore, the movable contact is separated from the fixed contact 33 by the urging force of the first movable piece 26. Then, the first movable piece 26 comes into contact with the contact portion 15 and its movement is restricted, that is, is held at this position, so that the first switching element 41 is in an open state. At the same time, the convex portion 64 separates from the second movable piece 46 and releases the movable piece. Therefore, the movable piece moves to the side of the second fixed piece 45 by the urging force, and the movable contact 54 comes into contact with the fixed contact 53, so that the second switching element 51 is closed. Become.

In this state, the plunger 61 does not contact the first movable piece 26 or the second movable piece 46, that is, the first movable piece 26 and the second movable piece 46 are free from the plunger 61. Is in a state.

Then, when the pressing of the plunger 61 is stopped, the plunger is returned to its original state by the urging force of the coil spring 71, and the first switching element 41 and the second switching element 51 are brought to the state shown in FIG. Return.

FIG. 8 shows an application example of the leaf switch according to the present invention, which is applied to a microwave oven. In this figure, a power supply 91 is connected to a load 94, for example, a load circuit 92 having a magnetron, a monitor circuit 93 is connected in parallel with the load circuit, and a monitor switch 97 is provided in the monitor circuit. A fuse 98 is provided between the monitor circuit 93 and the power supply 91, and latch switches 95 and 96 are provided between the load circuit 92 and the power supply 91. Also, latch switch 9
Reference numerals 5 and 96 are for opening and closing the load 94 in conjunction with opening and closing of the door, and the monitor switch 97 is in the open state when the door is closed, but is closed when the door is open and the latch switches 95 and 96. Load 94 when not open
Is short-circuited, and the fuse 98 is melted by this. As the monitor switch 97, the first switching element 41 of the leaf switch according to the present invention is used. The second switching element 51 is used for opening and closing a microcomputer circuit (not shown), and is energized when the door is closed.

"Effects" The present invention provides the housing with two sets of switching elements and the plungers for operating these switching elements as described above, and the first movable piece is provided with the first movable piece against the elasticity in the first position of the plunger. A first movable piece that is in electrical contact with the first fixed piece and that releases the first movable piece in the second position of the plunger and that separates the movable piece from the first fixed piece by its own elasticity. And the second movable piece in the first position of the plunger against the elasticity of the second fixed piece, and releases the second movable piece in the second position of the plunger. Moreover, since the second actuator that electrically contacts the movable piece with the second fixed piece by the elasticity of the movable piece is provided, the stress of the movable piece can be suppressed to be small, and A partition wall which can increase the contact pressure and which is separated into a first chamber in which the normally open switching element is located and a second chamber in which the normally closed switching element is located along the axis of the housing. Is provided, there is an advantage that the insulating property is improved.

Furthermore, since the first movable piece of the normally-closed switching element is released at the end of the partition wall at the free end side of both movable pieces, the movement is integrally formed so as to intersect the partition wall. The gap between the movable piece and the movable piece is always constant, which has the effect of improving the characteristics.

[Brief description of drawings]

FIG. 1 shows an embodiment of a leaf switch according to the present invention, and is a front view showing a cover removed, FIG. 2 is a front view for explaining the operation, FIG. 3 is an exploded perspective view, and FIG.
FIG. 5 is an external perspective view, FIG. 5 and FIG. 6 are operation explanatory views for explaining the operation of a conventional leaf switch, FIG. 7 is an analysis view, and FIG. 8 is an application example of the leaf switch in the present invention. It is a circuit diagram. 1 ... Housing, 1a ... Side wall, 1b ... Side wall, 1c ... Side wall, 1d ... Side wall, 3 ... Support wall, 4 ... Guide wall, 5 ... Guide groove, 6 ... Partition wall, 7 ... First chamber, 8 ... Second Chamber, 9 ... bottom wall portion, 10 ... notch portion, 11 ... reinforcing portion, 12 ... through hole, 1
3 ... Through hole, 14 ... Cylindrical part, 15 ... Abutting part, 16 ... Projection wall,
17 ... Fitting hole, 18 ... Fitting hole, 19 ... Fitting recess, 21 ...
Fitting groove, 22 ... Fitting groove, 25 ... First fixed piece, 26 ... First movable piece, 27 ... Convex portion, 28 ... Convex portion, 29 ... Convex portion, 3
DESCRIPTION OF SYMBOLS 1 ... Receiving part, 32 ... Projection part, 33 ... Fixed contact, 34 ... Movable contact, 37 ... Convex part, 38 ... Convex part, 41 ... First switching element, 42 ... Groove, 43 ... Holding part, 44 ... Projection Division, 4
5 ... 2nd fixed piece, 46 ... 2nd movable piece, 51 ... 2nd switching element, 53 ... Fixed contact, 54 ... Moving contact,
61 ... Plunger, 62 ... First actuator, 63 ... Second
Operator, 64 ... convex portion, 65 ... elongated hole, 66 ... convex portion, 67
... Engagement protrusions, 71 ... Coil springs, 81 ... Covers,
83 ... sprocket, 84 ... sprocket, 85 ... through hole, 86 ... through hole, 87 ... cylindrical portion, 88 ... ridge, 89 ... protruding wall, 90 ... guide convex portion, 91 ... power supply, 92 ... load circuit, 93 ... Monitor circuit, 94 ... Load, 95 ... Latch switch, 95 ... Latch switch, 97 ... Monitor switch, 98 ... Fuse.

Claims (1)

[Claims] 1. A normally closed switching element comprising a first fixed piece having a fixed contact and a first movable piece having a movable contact that selectively contacts the fixed piece, and a first fixed piece having a fixed contact. The second fixed piece and the second movable piece having the movable contact that selectively comes into contact with the second fixed piece constitute a normally-open switching element, and these two switching elements are arranged in the housing at predetermined intervals. On the other hand, the housing is slidably provided with a plunger for selectively opening and closing the switching elements on the free end sides of the movable pieces, and the plunger is provided between the plunger and the housing. A spring for urging one of them along its axis is provided, and the plunger is provided with the first movable member at the first position of the plunger. The movable contact of the piece is electrically contacted with the first fixed piece against the elasticity of the movable piece, and at the second position of the plunger, the first movable piece is released, and the movable piece is A first actuator that separates from the first fixing piece by its elasticity,
Separating the second movable piece from the second fixed piece against its elasticity at the first position of the plunger and releasing the second movable piece at the second position of the plunger; And, the second piece for electrically contacting the movable piece with the second fixed piece by its own elasticity
And a partition wall in the housing which separates a first chamber in which the normally open switching element is located and a second chamber in which the normally closed switching element is located along the axis thereof. And an insulating contact that restricts the movement of the normally-closed switching element within the predetermined range to the end portions of the partition walls at the free end sides of the movable pieces, while the first movable piece of the normally-closed switching element is released. A leaf switch that is integrally molded so that its part intersects the partition wall.