JPS6337448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switch device for electrical equipment such as a power tool.

[Conventional technology]

A conventional switch device used in a power tool is shown in FIG. That is, A is a switch handle, B ₁ and B ₂ are movable contacts connected to the battery,
C ₁ is a first fixed contact that is connected to one side of the forward and reverse rotation motor and serves as a common, and C ₂ and C ₃ are second fixed contacts that are integrally formed and switch polarity. Now the first fixed contact C ₁ and the second fixed contacts C ₂ and C ₃
When the stand D holding the is moved in the direction of the arrow E and the handle A is operated, the movable contact B ₁ and the first fixed contact C ₁ , as well as the movable contact B ₂ and the second fixed contact C ₃ come into contact with each other. For example, a + pole appears on the lead wire F, and when the stand D is moved to the opposite side of the arrow E and the handle A is operated, the movable contact B ₁ and the second fixed contact C ₂ as well as the movable contacts B ₂ and The first fixed contact _C1 is in contact with the lead wire F.
A single pole appears.

[Problem to be solved by the invention]

However, in such a switch device for electrical equipment, if an arc occurs in the movable contacts B ₁ and B ₂ and the first fixed contact C ₁ and the second fixed contact C ₂ and C ₃ when the contacts are opened, the contact There is a problem in that the surface becomes rough, the contact resistance increases, and the temperature rise when electricity is applied increases. Generally, heat generated by arcing at the contacts of electrical equipment switches damages the contact surfaces and shortens the life of the contacts. Therefore, in order to suppress the rise in the temperature of the contact and extend its life, it is said that it is better to increase the volume of the contact, but this has the drawback of increasing the size and material cost.

Therefore, an object of the present invention is to provide a switch device for electrical equipment that can reduce the temperature rise of the contacts and improve the life of the contacts without increasing the size or increasing the material cost. be.

[Means to solve the problem]

A switch device for electrical equipment according to the present invention includes a first fixed contact, which is located adjacent to the first fixed contact and rearward of the first fixed contact, and has a volume larger than that of the first fixed contact. a pair of leaf springs each holding a large second fixed contact, a pair of movable contacts that contact the first fixed contact and the second fixed contact, and having a larger volume than the second fixed contact; a switch handle that presses a leaf spring to bring the movable contact into contact with the first fixed contact and the second fixed contact,
The first fixed contact and the second fixed contact are connected to both ends of one of the load and the power source, the movable contact is connected to the other end of the load and the power source, and the movable contact is connected to both ends of the other of the load and the power source, and the movable contact is A contact contacts the first fixed contact earlier than the second fixed contact, and the movable contact that contacts the first fixed contact comes later than the movable contact that contacts the second fixed contact. It is something that separates from.

[Effect]

According to the configuration of the present invention, when the handle is operated, the movable contact contacts the first fixed contact before the second fixed contact, and when the movable contact separates, the first fixed contact separates later. . Therefore, a circuit including a power source and a load is opened and closed by contact and separation between the second fixed contact and the movable contact. Therefore, since the arc is generated at the second fixed contact having a large volume, the temperature rise can be reduced, and the life of the contact can be improved without increasing the size or material cost.

〔Example〕

An embodiment of the invention is shown in FIGS. 2 to 11. That is, the switch device of this electric device includes a first fixed contact 66, which is located adjacent to the first fixed contact 66 and rearward of the first fixed contact 66, and further from the first fixed contact 66. Second fixed contacts 68a, 68b having a large volume, first fixed contacts 66, second fixed contacts 68a,
A pair of movable contacts 34 and 35 that contact 68b are held respectively, and a second fixed contact 68a,
A pair of leaf springs 32, 3 having a larger volume than 68b
3 and press these leaf springs 32, 33 to move the movable contacts 34, 35 to the first fixed contact 66 and the second fixed contact 66.
The first fixed contact 66 and the second fixed contact 68a, 68b are connected to both ends of either the load or the power supply, and the movable contact 3
4, 35 are connected to the other ends of the load and the power source, and the movable contacts 34, 35 are connected by operating the handle 25.
35 is the first fixed contact than the second fixed contact 68a, 68b.
The movable contacts 34 and 35 contact the fixed contact 66 first, and the first fixed contact 66 is separated from the second fixed contacts 68a and 68b.

This will be explained in detail below. This power tool has a pistol-shaped two-part housing 11 that forms a body part 12 and a handle part 13. The body part 12 has a motor 14, which is a load, installed in the rear end of the body part 12, and the front side of the motor 14 is A transmission 15 is disposed, a reduction gear 16 is disposed in front of it, and a chuck 1 is disposed at the front end of the body 12.
7, and a speed change handle device 18 for switching the speed change device 15 is provided above the motor 14 at the rear end of the body 12. In addition, a rechargeable battery pack 19 containing a built-in rechargeable battery 19a serving as a power source is removably loaded into the handle portion 13 using a hook operating portion 19b, and a device near the base of the handle portion 13 serves as a switch for turning on/off the power and for switching forward/reverse rotation. A switch device 20 is provided, and power from the rechargeable battery is supplied to the motor 1 via the switch device 20.
4. In this way, the switch device 20 operates the motor 14, which is a load, and the transmission device 1
Rotation is transmitted to the chuck 17 via the speed reducer 16 at the rotational speed switched at step 5. Note that a torque adjustment device 21 is incorporated in the reduction gear device 16.

Now, the switch device 20 has a structure in which a movable terminal block 24 is supported by a switch cover 23 on the upper surface of the terminal block 22, a switch handle 25 is provided on the terminal block 22, and a switching handle 26 is provided on the switch cover 23. Both are made of insulating material. First, when viewed from the side, the terminal block 22 has a substantially inverted L shape consisting of a horizontal portion 27 and a vertical portion 28, and the vertical portion 28 is slightly inclined toward the horizontal portion. A vertical partitioning rib 29 is provided at the center of the front side of the vertical portion 28, a pair of fixing protrusions 30, 31 are formed at the lower end of the front surface with the vertical partitioning rib 29 in between, and a pair of conductor plate springs 32, 33 are formed on this. Holes 32a, 3 at the lower end of
The plate springs 32 and 33 are fixed by fitting the fixing protrusions 30 and 31 and heat-sealing them. The upper end portions of these leaf springs 32 and 33 extend forward and upward of the horizontal portion 27, and movable contacts 34 and 35 are provided protrudingly on the horizontal portion side as shown in FIG. has been established. Also leaf spring 3
A spring receiving protrusion 37 is formed facing the vertical part 28 at a position corresponding to the upper end of the vertical part 28 in the middle part of the leaf springs 32 and 33, and extends in the width direction at the lower end of the leaf springs 32 and 33 and is bent at a right angle. A support plate 38 is formed on the side surface of the lower end of the vertical portion 28 of the terminal block 22, and power terminals 39 and 40 are formed on the upper end of the rechargeable battery pack 19 further from the end of the support plate 38 (see FIG. ) extends at right angles to the width plate 41 that determines the contact position with respect to the
Planar U-shaped plates 42 and 43, which are parallel to the support plate 38 and located behind the vertical portion 28 of the terminal block 22, extend further from the end of the width plate 41, and their free ends are tilted in the direction in which they face each other to connect the power source. Power receiving terminals 44 and 45 are in contact with the terminals 39 and 40. A guide box 46 parallel to the horizontal part 27 is formed below the horizontal part 27 at the upper end of the vertical part 28 of the terminal block 22, an opening 47 is formed in the front end of the guide box 46, and a guide groove 48 is formed in the inner wall. Spring receiving holes 49 are formed on both sides of the opening 47, and compression coil springs 50 are installed between the spring receiving holes 49 and the spring receiving protrusions 37 of the leaf springs 32 and 33, respectively, as shown in FIG. 32,3
3 in the direction away from the terminal block 22.

The switch cover 23 has a box shape with openings at the lower end and the front end, and as shown in FIG. When the housing 11 is positioned on the horizontal portion 27 by being engaged with the housing 11 and installed in the handle portion 13 of the power tool
It is fixed on the horizontal part 27 by the rib 11a. This switch cover 23 has a rectangular guide hole 54 formed in the front end of the upper plate 53 and is long in the horizontal direction.
A stepped wall 55 is formed upwardly projecting on the front end side through the guide hole 54, a shaft 56 is projected forward at the center of the front surface of the stepped wall 55, and a shaft 57 is erected on the shaft 56. At the same time, a pair of recesses 58 are provided on the lower surface of the axle base 56.
(Fig. 5) and engages the upper ends of the leaf springs 32, 33, thereby regulating the operating range of the leaf springs 32, 33. Further, as shown in FIG. 10, three positioning grooves 58a having a triangular cross section are arranged on the lower surface of the rear end side of the guide hole 54 of the upper plate 53 in the longitudinal direction of the guide hole 54.
58c are formed, and a guide plate 59 is suspended from the rear end of these grooves 58a to 58c (FIG. 5).

The movable terminal block 24 has a rectangular shape that is supported in front of the guide plate 59 in the switch cover 23 so as to be slidable in the horizontal direction on the upper surface of the horizontal portion 27. A pair of protrusions 60a, 60b are formed to form protrusions 60a, 60b.
A cam groove 61 is formed between the protrusions 60a and 60b.
Both ends of a plate spring 63, which has protrusions 62 bent to engage with the positioning grooves 58a to 58c formed on the rear end side of the movable terminal block 24, are fixed, and three thin strips are provided on the lower surface of the movable terminal block 24, opening at the front end and the lower end. Grooves 64a to 64c
are formed at regular intervals, a communication groove 65 is formed across the narrow grooves 64a to 64c as shown in FIG. , a second fixed contact 68 consisting of a pair bridged by a bridging piece 67 located in the communication groove 65
a, 68b are buried in the narrow grooves 64a, 64c on both sides. Their respective rear ends are supported by the inner ends of the narrow grooves 64a to 64c, and their arcuate front ends protrude from the front surface of the movable terminal block 24. Contact surfaces 69b, 69c of the second fixed contacts 68a, 68b, and lead wires 70a, 70b for connecting the motor 14, which is a load, to the rear ends of the first fixed contacts 66 and the second fixed contacts 68a. The ends are soldered. By integrally forming a pair of second fixed contacts 68a and 68b, the first fixed contacts 66
It has a larger volume. In addition, as shown by dimension 1 in FIG. 8, the first fixed contact 66 and the second
This causes the first fixed contact 66 to come into contact with the movable contacts 34, 35 before the second fixed contacts 68a, 68b, and to separate later. Therefore, the first fixed contact 66 does not open or close the circuit to prevent arcing. In addition, the movable terminal block 24 has a horizontal portion 2 from a predetermined position on the lower surface of its front end.
A lock protrusion 71 hanging down from the front surface of the lock 7 is provided. The movable terminal block 24 configured in this manner can be slid laterally within the switch cover 23;
Since the protrusion 62 of the leaf spring 63 engages with the grooves 58a to 58c, it can be moved to three positions designated by these grooves 58a to 58c. At this time, contact surface 6
9a to 69c are movable contacts 3 of leaf springs 32, 33
4 and 35, and more precisely, when the leaf springs 32 and 33 are brought close to the contact surfaces 69a to 69c, and the movable terminal block 24 has its protrusion 62 aligned with the grooves 58a and 58a.
The dimensional relationship is such that the movable contacts 34 and 35 come into contact with the contact surfaces 69a and 69b or the contact surfaces 69a and 69c when the movable contacts 34 and 35 are in the positions on both sides engaging with the contact surface 8c.

The switching handle 26 vertically passes through a shaft hole 72 in the center, and has a downward operating protrusion 73 formed at one end.
The other end is an operating section 74. When the shaft hole 72 of the switching handle 26 is rotatably fitted to the shaft 57 of the switch cover 23, the operating projection 73 engages with the cam groove 61 formed by the projections 60a, 60b of the movable terminal block 24. Also housing 1
When attached to the handle part 13 of 1, the hole 7 formed on the front side of the base of the handle part 13 as shown in FIG.
An operating section 74 protrudes from 5. On the other hand, when the operating portion 74 of the switching handle 26 is rotated in the horizontal direction, the switching handle 26 is rotated about the shaft 57, and the operating protrusion 73 is rotated to push the protrusions 60a and 60b, so that the movable terminal block 24 in the horizontal direction,
The protrusion 62 of the leaf spring 63 moves from the groove 58a to the groove 58c. At this time, due to the spring action of the protrusion 62, the switching handle 26 provides a click feeling when operated.

The switch handle 25 has an operation surface 76 on one side.
A guide plate 77 is protruded from the opposite side, a lock protrusion 78 is formed at a predetermined position on the upper surface of the guide plate 77, and a pair of spring receiving holes 79 are formed at the upper end of the opposite side as shown in FIG. Furthermore, a locking protrusion 76a hangs down from the lower end as shown in FIG. The switch handle 25 is slidably inserted into the opening 47 of the terminal block 22 through a guide plate 77 between the leaf springs 32 and 33, and is supported by the leaf springs 32 and 33.
A compression coil spring 80 is installed between the spring receiving projection 36 and the spring receiving hole 79 to apply contact pressure. Further, when attached to the handle portion 13, a locking protrusion 76a projects outward from the lower part of the switching handle 26 of the hole 75 and locks with the lower edge of the hole 75. Therefore, when the handle portion 13 is grasped and the operating surface 76 of the switch handle 25 is pulled with the index finger, the compression coil spring 80 is compressed and the leaf springs 32 and 33 are compressed.
, and compresses the coil spring 50 to cause the movable contacts 34 and 35 to contact the contact surfaces 69a of the first fixed contact 66 and the second fixed contacts 68a and 68b facing each other.
69c, and constant contact pressure is applied between the contacts by compression of the compression coil spring 80.
Further, when the index finger is released from the switch handle 25, the coil spring 50 is restored, causing the leaf springs 32 and 33 to be separated, and the compression coil spring 80 is restored, so that the switch handle 25 is restored. The relationship between the protrusion 78 and the lock protrusion 71 is as shown in FIGS. 9 and 10, when the protrusion 62 of the movable terminal block 24 is engaged with the groove 58b, they face each other and the switch handle 25 is Even when pulled, the protrusion 78 and lock protrusion 71
The plate springs 32 and 33 are made inoperable by abutting against each other.

FIG. 11 is a list of operations of the switch device.
That is, column a in the figure shows a state in which the switching handle 26 has been rotated to the first position, and at this time, the lock protrusion 71 and the protrusion 78 do not face each other, and the protrusion 62 of the movable terminal block 24 is in the groove 58a. The movable contacts 34, 35, the contact surface 69a of the first fixed contact 66, and the contact surface 69b of the second fixed contact 68a face each other. Therefore, switch handle 2
When 5 is pulled, the movable contact 34 and the first fixed contact 66 first come into contact, and then the contact surfaces 69b of the movable contact 35 and the second fixed contact 68a come into contact and are electrically connected.
A leaf spring power receiving terminal 44 from the rechargeable battery pack 19,
The current input to 45 is connected to lead wire 7 with the polarity shown in the figure.
0a and 70b. Column b in the figure shows a state in which the switching handle 26 has been rotated to the second position (neutral position). At this time, the movable terminal block 24 moves and the spring protrusion 62 moves into the groove 58b of the switch cover 23.
, the protrusion 78 of the switch handle 25 and the lock protrusion 71 face each other, and the contact surfaces 69a to 69
9c no longer faces the movable contacts 34, 35. In this case, when the switch handle 25 is pulled, the protrusion 78 hits the lock protrusion 71 before the movable contacts 34, 35 come into contact with the movable terminal block 24, and the switch handle 25 cannot be pushed any further. That is, this neutral state is a locked state. Column c in the figure shows a state in which the switching handle 26 has been rotated to the third position, the spring protrusion 62 is engaged with the groove 58c, the protrusion 78 is not opposed to the lock protrusion 71,
The movable contacts 34 and 35 are connected to the contact surface 69a of the first fixed contact 66 and the contact surface 6 of the second fixed contact 68b.
Opposite 9c. Therefore, the switch handle 25
When pulled, the movable contacts 34 and 35 move into phase sequentially in the order of the pair of the movable contact 35 and the contact surface 69a of the first fixed contact 66, and then the pair of the movable contact 34 and the contact surface 69c of the second fixed contact 68b. When they come into contact, the lead wires 70a and 70b exhibit polarities opposite to the operation in a, and the motor 14, which is the load, rotates in the opposite direction to the operation in a. Looking at the contact of the contacts here, the first fixed contact 66 is connected to the second fixed contacts 68a, 68.
Since it protrudes from b, the first fixed contact 66 contacts first, but when the contact is opened, it separates later, so no arc occurs at the first fixed contact 66,
Second fixed contacts 68a, 68 on the opening/closing side of the circuit
This will occur at point b. For this reason, the first fixed contact 6 has a small volume and a high temperature rise due to arcing.
Compared to the case where the life of the switch is determined by the life of the contacts No. 6, in this embodiment, the arc is generated at the second fixed contacts 68a and 68b, which are twice as large in volume, resulting in a large capacity. Moreover, the lifespan is extended. Furthermore, since the movable contacts 34 and 35 are supported by larger leaf springs 32 and 33, there is no problem.

Note that the leaf springs 32 and 33 are compression coil springs 50.
Even without the leaf spring, it can be opened using the spring force of the leaf spring itself. In addition, the switch handle 25 is restored to its original state by the leaf springs 32 and 33, and the compression coil spring 8
0 may be omitted.

〔Effect of the invention〕

According to the switch device for electrical equipment of this invention,
When the handle is operated, the movable contact contacts the first fixed contact before the second fixed contact, and when the movable contact separates, the first fixed contact separates later. Therefore, a circuit including a power source and a load is opened and closed by contact and separation between the second fixed contact and the movable contact. Therefore, since the arc is generated at the second fixed contact having a large volume, the temperature rise can be reduced.
Moreover, there is an effect that the life of the contact can be improved without increasing the size or increasing the material cost.

[Brief explanation of the drawing]

Fig. 1 is a horizontal sectional view of a conventional example, Fig. 2 is a partial sectional side view of a power tool to which an embodiment of the present invention is applied, Fig. 3 is a sectional view taken along the line 1, and Fig. 4 is an exploded view of the switch device. 5 is a sectional view of the switch device, FIG. 6 is a half-sectional front view thereof, FIG. 7 is a sectional view taken along the line 5, FIG. FIG. 5 is a sectional view taken along the line in FIG. 5, FIG. 10 is a sectional view taken along the line shown in FIG. 5, and FIG. 11 is a list of operations of the switch device. 14...Motor as load, 19a...Rechargeable battery as power source, 25...Switch handle, 32, 33
... Leaf spring, 34, 35... Movable contact, 66... First fixed contact, 68a, 68b... Second fixed contact.

Claims (1)

[Scope of Claims] 1. A first fixed contact, and a second fixed contact that is adjacent to the first fixed contact, is located behind the first fixed contact, and has a larger volume than the first fixed contact. a pair of leaf springs each holding a fixed contact, a pair of movable contacts that contact the first fixed contact and the second fixed contact, and having a larger volume than the second fixed contact, and these leaf springs. a switch handle that presses the movable contact to bring the movable contact into contact with the first fixed contact and the second fixed contact; the movable contact is connected to the other end of the load and the power source, and when the switch handle is operated, the movable contact contacts the first fixed contact earlier than the second fixed contact. At the same time, the movable contact that has contacted the first fixed contact contacts the second fixed contact.
A switch device for electrical equipment that is separated from the movable contact after it has come into contact with the fixed contact. 2. The switch device for electrical equipment according to claim 1, wherein the second fixed contact comprises a pair of contact surfaces for polarity switching, and each contact surface is adjacent to both sides of the first fixed contact. .