JPH0526665Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field This invention relates to a switch for a power tool driven by a DC motor, such as an electric screwdriver, an electric drill, an electric saw, and the like.

(B) Prior Art As a conventional switch for a power tool, there is, for example, a device described in Japanese Patent Application No. 160918/1980, which has a built-in transmission section for variably controlling the rotational speed of a motor for a power tool.

However, in this type of switch, it is difficult to compactly incorporate the switching part that switches the rotation direction of the power tool motor between forward and reverse in the same location as the above-mentioned transmission part. It is located in a separate part of the power tool grip, away from the transmission part.

(c) Problems to be solved by the invention For this reason, the switching operation requires both hands, and the installation space is restricted, resulting in the switching device being placed in a position that is difficult to operate, resulting in poor operability.

This idea provides an easy-to-operate power tool switch in which the transmission section and switching section are efficiently and compactly arranged in the grip of the power tool, and the transmission section and switching section can be switched and operated with one hand. For the purpose of providing.

(d) Means for solving the problem This invention is a power tool switch that is equipped with a trigger lever for controlling the driving and stopping of the motor, and a switching lever for switching the rotation direction of the motor between forward and reverse, in the grip of the power tool. An insulating operating disk is rotatably housed in the case, and the operating disk is equipped with a conductive disk in which the middle part and both ends of the meniscus are exposed on either the front or back side. are integrally formed with the center point of the meniscus as the center of rotation of the operating disk, and the surface of the operating disk where the center of each meniscus is exposed is provided with the center point of the operating disk. Motor terminals that are in constant contact regardless of rotation are arranged, and the surface of the operating disk where both ends of each meniscus are exposed is provided with motor terminals that are in contact with each other at all times regardless of rotation. a positive power supply terminal and a negative power supply terminal that selectively come into contact with each other are respectively disposed, and the switching lever capable of tilting by a certain amount is formed protrudingly on a side surface of the case that intersects with the operating position of the trigger lever, A switch for a power tool in which the switching lever is pivotally connected to a slide lever that slides when the switching lever is tilted, and the slide lever is engaged with the operating disc so that the operating disc can rotate at a certain angle. characterized by something.

(e) Effects of the invention According to this invention, since the operating position of the switching lever is arranged in the case so as to intersect with the operating position of the trigger lever, when the case is arranged in the grip of a power tool, , the area around the grip part is effectively utilized for a compact installation position, and both levers can be positioned close to the hand of the grip part, making it easy to operate each lever with one hand holding the grip part. Can be easily operated.

In particular, if the switching lever is located on the thumb side of the grip, it is possible to efficiently operate both levers, for example, by using the switching lever with the thumb and the trigger lever with the index finger, respectively, in a state suitable for each operation.

In addition, a conductive meniscus that serves as a contact point is integrally formed on the operating disk for switching, so
It is possible to reduce the number of parts and make it more compact, and at the same time, it is possible to simplify the assembly work.

Furthermore, since the switching contact portion can be formed compactly, the compact arrangement of the trigger lever and the switching lever with respect to the aforementioned grip portion can be made more effective.

(F) Embodiment An embodiment of this invention will be described below in detail based on the drawings.

The drawing shows a switch for a motor for an electric tool. In FIGS. 1 to 4, this switch includes a control circuit section 11 for a DC reversible motor, a forward/reverse switching section 12 for switching the rotation direction of the motor between forward and reverse directions, and a switch for controlling the motor. It is comprised of a trigger lever 13 for driving and operating the trigger lever 13, and a switch case 14 for supporting these, and is used by being incorporated into the grip of a power tool such as an electric screwdriver.

The control circuit section 11 described above includes two FETs (field effect transistors) 15 and 16, and these FETs 1
5 and 16, and a gate-shaped board 18.
, a printed circuit board 19 on which a control circuit is mounted, a brush 21 that makes sliding contact with a resistor board 20 to vary the resistance value, and an insulating slider 2 with movable contacts.
2, and a return spring 23 for this slider 22.

The heat dissipation cover 17 described above is provided in a box shape with an open bottom surface, and the FET described above is installed in this open bottom surface.
15, 16 and the gate-shaped board 18, square holes 24 opened on both sides of the heat dissipation cover 17 engage with side protrusions 25 protruding from the outer surface of the switch case 14, which will be described later. The switch case 14 is then integrally fitted onto the switch case 14.

A lever engagement hole 2 into which an idle lever 26 (described later) is inserted is provided on the lower front side of the slider 22 described above.
7 is open, and the slider 22 is slid in the front-rear direction by the depression stroke of the trigger lever 13 via the idle lever 26.

When the brush 21 attached to the front side of the upper surface of the slider 22 is slid, its contact position with the resistance board 20 is gradually displaced, thereby changing the resistance value for torque control of the motor.

The above-mentioned switch case 14 is provided in the shape of a box with an open top surface, and the above-mentioned slider 22 is housed in this top surface opening 28 so as to be slidable in the front and back direction, and the printed circuit board 19 and the FET are placed above the slider 22.
15 and 16 are a gate-shaped board 18 and a heat dissipation cover 17
The square holes 24, 24, .

Furthermore, on the rear side wall 29 of the top opening 28,
Several terminal mounting grooves 30, 31 are formed, and a positive power terminal 32 and a negative power terminal 33 are inserted into the terminal mounting grooves 30, 30 on both sides, and the terminal mounting grooves 31, 31 between them are inserted. 31, a first motor terminal 34 and a second motor terminal 35 are respectively inserted and attached.

Further, a cylindrical shaft 36 is provided on the bottom upper surface of the upper surface opening 28.
An insulating operating disc 37, which will be described later, is rotatably pivotally mounted to this cylindrical shaft 36.

As shown in FIG. 5, this operating disc 37 is made by insert-molding a first meniscus 38 and a second meniscus 39 integrally with a resin material so as to be flush with the lower surface thereof. The operating disk 37 is configured to be rotatable about the center point of each meniscus 38, 39 as a pivot point.

Further, each of the meniscuses 38 and 39 described above has rising portions 38a, 38b, 39a, and 39b integrally formed at both ends thereof, and these rising portions are exposed on the upper surface of the operating disk.

Further, the arcuate contact portion 34a of the first motor terminal 34 is always in contact with the lower surface of the first meniscus 38, and the arcuate contact portion 34a of the second motor terminal 35 is in constant contact with the lower surface of the second meniscus 39. The shaped contact portion 35a is kept in constant contact.

Furthermore, under the normal state shown in FIG. 6, the rising portion 38 on one side of the first meniscus 38
The arcuate contact portion 40a of the positive power supply terminal 40 is pressed into contact with the arcuate contact portion 40a of the positive power supply terminal 40, and the arcuate contact portion 41 of the negative power supply terminal 41 is brought into pressure contact with the rising portion 39b on the other side of the second meniscus 39.
A is brought into pressure contact.

Then, the aforementioned operating disc 37 is switched to the seventh operating disc via a switching lever 42, which will be described later.
When the state shown in the figure is rotated by a predetermined angle, the arcuate contact portion 41a of the negative power supply terminal 41 is brought into pressure contact with the rising portion 38b on the other side of the first meniscus 38, and the second meniscus 39 is rotated by a predetermined angle. Rising part 39 on one side
The arc-shaped contact portion 40a of the positive power supply terminal 40 is brought into pressure contact with the terminal a.

In other words, the first meniscus 38 described above has a structure in which the lower surface is always in contact with the first motor terminal 34 and the upper surface is in selective contact with the positive power terminal 40 and the negative power terminal 41. second meniscus 39
is in constant contact with the second motor terminal 35 on its lower surface, and in contact with the negative power terminal 41 and the positive power terminal 40 on its upper surface.
The structure is such that it selectively comes into contact with both.

Here, the above-mentioned power terminals 40, 41 are fixed along the inner wall of the upper opening 28 of the switch case 14, and the upright portion 41b of the negative power terminal 41 of these power terminals 40, 41 is connected to the gate. shaped board 18
The upright portion 33b of the above-mentioned negative power terminal 33 is also electrically connected to the conductive plate of the gate-shaped board 18.
electrically connected to a conductive plate.

Further, an engagement protrusion 43 for engaging and fixing a switching lever 42 to be described later is provided protrudingly on the upper surface of one peripheral edge of the aforementioned operating disc 37. Lower square hole 44a of slide lever 44 inserted from one side and exposed
to the outer end of this slide lever 44,
A switching lever 12 is pivotally mounted.

This switching lever 42 is connected to a pivot pin 42a protruding from the upper surface of the lever by being pivotally connected to a pivot recess 44b formed in the slide lever, and the switching lever 42 is pivoted in the front-rear direction using this pivot part as a fulcrum. The switching lever 42 is allowed to tilt by a certain amount.
It is regulated via first and second fixing pieces 46a and 46b arranged in the.

The outer end of the switching lever 42 protrudes from one side of the switch case 14, and by tilting the switching lever 12 in the front-rear direction, an internal operating disk is operated via the slide lever 44. 37 is rotated by a certain angle, and the contact is switched between a contact on the forward rotation side of the motor and a contact on the reverse rotation side of the motor.

A cap mounting hole 49 is provided in the front bottom of the switch case 14 for mounting a guide cap 48 having an idle lever insertion hole 47. is inserted into the case 14.

Furthermore, a support piece 50 is vertically provided on the lower surface of the switch case 14, and this support piece 50 has a communication groove 51 in the front-rear direction that communicates with the idle lever insertion hole 47 described above, and has a pivot support on both sides of the upper part. pin 52,5
2 are provided protrudingly, and a trigger lever 13, which will be described later, is pivotally attached to these pivot pins 52, 52.

The trigger lever 13 is formed in a semi-cylindrical shape, and the cylindrical surface is set as a pressing operation surface 53 on the front side. A pivot hole 54 is formed in the upper part of the lever 13.
By pivotally mounting the trigger lever 13 on the pivot pin 52, the trigger lever 13 can be tilted in the front-rear direction with the upper end portion as a fulcrum.

An idle lever 26 is interposed between the trigger lever 13 and the slider 22 described above.

This idle lever 26 is connected to the above-mentioned communication groove 51.
The idle lever 26 is attached to an arc-shaped pivot projection 55 located inside the support piece 50 and formed on the inner surface of the intermediate portion of the support piece 50.
By pivoting an intermediate recess 56 formed in the intermediate part of the
The lever 26 is provided so as to be tiltable in the front-rear direction. The upper end of this pivoted idle lever 26 is engaged with the lever engagement hole 27 of the slider 22, and the lower end side surface is locked with the inner surface of the trigger lever 13.
The idle lever 26 is supported by a ball 58 whose lower end is urged upward via a spring 57.

In the figure, 59 is a gate terminal, 60 is a terminal fixing pin, 61 is an insertion hole cap, and 62 is a sealing sponge.

The switch for a DC power tool configured in this way is usually arranged in the grip of the power tool, and the trigger lever 13 is normally connected to the return spring 23 inside the switch.
Under the biasing action of , the handle is in a state where it can be pushed down and protruded forward from the front surface of the grip using the pivot hole 54 at the upper end as a fulcrum.

By pressing the trigger lever 13 in the gripping direction, the slider 22 slides forward via the idle lever 26, and this sliding action turns on the power and starts the motor M.

At this time, by adjusting the stroke based on the pressing stroke of the trigger lever 13, the FETs 15, 1
By displacing the contact position between the brush 21 and the resistance board 20 via the speed change control circuit 6, the torque of the motor M is variably controlled and adjusted to a desired output torque suitable for the usage situation of the power tool. be done.

On the other hand, when the pressing operation of the trigger lever 13 is released, the slider 22 slides to the original rear end side under the return action of the return spring 23, and the trigger lever 13 also returns to its original tilted state. Since each movable contact piece returns to its normal position, the power is turned off.

By the way, in order to drive the above-mentioned motor M in normal rotation, the switching lever 42 formed in the lateral direction corresponding to the thumb side of the power tool grip section is tilted toward the front side.

As a result, the operation disk 37 is rotated by the sliding action of the slide lever 44, and as shown in FIG.
Then, the positive power terminal 40 and the negative power terminal 41 are brought into contact with the rising portion 39b on the other side of the second meniscus 39, respectively, and the motor M is rotated in the normal direction.

Conversely, by tilting the switching lever 42 rearward, the operation disk 37 is rotated by the sliding action of the slide lever 44, and the rising portion 38b on the other side of the first meniscus 38 is rotated as shown in FIG.
The arc-shaped contact portion 41a of the negative power supply terminal 41 is brought into contact with the rising portion 39a on one side of the second half-moon plate 39, and the positive power supply terminal 40 is brought into contact with the rising portion 39a on one side of the second half-moon plate 39.
The above-mentioned motor M is switched to a reverse driving direction.

In this way, since the operating position of the switching lever is arranged to intersect with the operating position of the trigger lever,
These levers are arranged to make effective use of the area around the grip, and both levers can be positioned close to the grip, making it easy to operate each lever with one hand holding the grip. can do.

[Brief explanation of drawings]

The drawings show one embodiment of this invention, and Fig. 1 is an external perspective view of the switch, Fig. 2 is a longitudinal side view of the switch, Fig. 3 is a longitudinal sectional front view of the main part of the switch, and Fig. 4
The figure is an exploded perspective view of the main parts of the switch, Figure 5 is a perspective view of the forward/reverse switching section, Figure 6 is an electrical circuit diagram showing the circuit configuration in the forward switching state, and Figure 7 is the circuit diagram showing the circuit configuration in the reverse switching state. It is an electrical circuit diagram. 12...Forward/reverse switching unit, 13...Trigger lever, 14...Switch case, 32...Positive side power terminal, 33...Minus side power terminal, 34...
...First motor terminal, 35...Second motor terminal, 3
7... Operating disc, 38... First meniscus, 39...
Second meniscus, 42...Switching lever, 44...Slide lever, M...Motor.

Claims (1)

[Scope of Claim for Utility Model Registration] A switch for a power tool, which is equipped with a trigger lever for controlling the driving and stopping of a motor, and a switching lever for switching the direction of rotation of the motor between forward and reverse, in the grip of the power tool, which is insulating. The operating disk is rotatably housed in the case, and the operating disk includes two conductive menisci with the middle part and both ends of the meniscus exposed on either the front or back side. are integrally formed with the center point of the meniscus as the center of rotation of the operating disk, and a surface of the operating disk where the intermediate portion of each meniscus is exposed is always provided with a Motor terminals that come into contact are arranged respectively, and either one of the two ends comes into contact with the surface of the operating disk where both ends of each meniscus are exposed by rotation of the operating disk. a positive power supply terminal and a negative power supply terminal respectively disposed therein, and a switching lever capable of tilting a certain amount protrudingly formed on a side surface of the case that intersects with the operating position of the trigger lever; A switch for a power tool, which is pivotally connected to a slide lever that slides when the switching lever is tilted, and the slide lever is engaged with the operating disc so that the operating disc can be rotated by a certain angle.