JP2012245605A - Trigger switch for power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trigger switch which has achieved a semipermanent sliding life and environmental resistance by way changing, in particular, a contact part into a contactless part so that it is free from any malfunction even if moisture or the like intrudes therein.SOLUTION: The trigger switch for a power tools built in a case is a type of a trigger switch having a slide operation part that operates in conjunction with the operation of a trigger lever while the slide operation part operates to mount a permanent magnet on the side surface of a speed control section that operates in conjunction with the entrainment operation of the trigger lever, and the trigger switch has a magnetic field sensor on a circuit board located at a position opposed to the speed control section while bringing the permanent magnet provided on the speed control section when the speed control section which operates in conjunction with the entrainment operation of the trigger lever is shifted to the entrainment direction to generate a signal affected by the change in the magnetic field over the magnetic field sensor, thereby controlling the speed of a motor based on the thus generated signal.

Description

  The present invention relates to a trigger switch for an electric tool, and more particularly to a trigger switch that is applied to a trigger switch for various electric tools and has a contactless contact so that a malfunction does not occur even if moisture enters the trigger switch. In particular, the present invention relates to a trigger switch for an electric tool effective for a battery-type brushless electric tool.

  As shown in FIG. 6, the trigger switch for a power tool in the prior art incorporates a sliding contact mechanism (speed control unit) inside a box shape, and transmits a sliding operation from the external trigger lever 11. A case 12 having a sliding operation portion 15 and having an opening on the side surface, a cover 14 having a sliding circuit board 13 mounted on the inner side surface and closing the opening surface on the side surface of the case 12, can be operated with fingers. The trigger lever 11 and the switching operation unit 25 that switches the forward / reverse rotation of the motor at the upper position of the case 12 are provided.

  The case 12 is formed in a box shape with an open side, and has the same shape as the upper lever guide portion 17 provided at the upper position for guiding the trigger lever 11 on the front side and the upper lever guide portion 17. A lower lever guide portion 18 provided at a lower position in the vertical direction is provided, and a speed control portion 44 that forms the sliding operation portion 15 in the depth direction sandwiched between the upper lever guide portion 17 and the lower lever guide portion 18 inside. Of the speed control unit storage chamber 19 and the switching lever 26 that constitutes the switching operation unit 25 at the upper position of the speed control unit storage chamber 19. The moving shaft storage chamber 21 or the contact portion storage chamber 22 for storing the contact portion 30 of the switching lever 26 constituting the switching operation portion 25 continuously provided in the rotating shaft storage chamber 21 via a shielding member. It made.

  The cover 14 is configured to include a board mounting portion 24 for mounting the rectangular sliding circuit board 13 on the inner side wall.

  The switching lever 26 that constitutes the switching operation unit 25 includes a switching knob 28 that protrudes upward at the upper end of a main body 27 formed in a trapezoidal shape, and the switching lever 26 is pivotable at a substantially central position. A rotating shaft 29 serving as a shaft, and a contact piece portion 30 for mounting a switching contact piece 31 formed of a conductive metal member that generates a switching signal on the side surface of the rear end portion, are provided with an oscillating spring 32 and an oscilloscope at the rear end portion. 33 is provided.

The rotating shaft storage chamber 21 is a chamber in which the rotating shaft 29 of the switching lever 26 is engaged with the rotating shaft engaging hole 23, and a main body portion 27 and a main body portion that are formed one step higher than the rotating shaft 29. The switching lever 26 connected to 27 is positioned outside the case 12.
The upper portion of the rotation shaft engaging hole 23 formed in the rotation shaft storage chamber 21 is extended and formed so as to close the top surface of the rotation shaft 29 when the rotation shaft 29 is engaged. The top wall 36 has a structure.

  The contact piece storage chamber 22 is a room for storing the contact piece portion 30 including the switching contact piece 31 of the switching lever 26, and the sliding portion 31 is mounted on the cover 14 in this room. The switching contact pieces 31 are arranged in a state of being opposed to the switching contacts 34 a and 34 b disposed on the circuit board 13, and the switching contact piece 31 is in electrical contact with the switching contacts 34 a and 34 b by the operation of the switching knob 28.

  The sliding operation portion 15 is formed in a rod shape and has a free end portion to which an O-ring 38 and an external packing 39 are attached, a trigger shaft 11 to which a trigger lever 11 can be attached, and a base portion side of the sliding shaft 41. In this structure, two sliders 42 and 43 are arranged in parallel to the side surface and a speed control unit 44 for controlling the rotational speed of the motor is provided.

  The sliding shaft 41 has a configuration in which an O-ring 38 and an external packing 39 are attached, the tip side thereof is attached to the trigger lever 11, and the E-ring 59 is inserted so as not to be detached from the trigger lever 11.

  The speed control unit 44 includes a speed control slider 42 and a switch slider 43 that are coupled to the slide shaft 41 and interlocked with the slide shaft 41, and the speed control slider 42 and the switch slider 43 are connected to the speed control slider 42. It is comprised from the sliding circuit board 13 provided with the contacts 45, 46, 47, 48 for elastic contact.

  The sliding circuit board 13 has switching contacts 34 a and 34 b that contact the switching contact piece 31 of the switching operation unit 25 on the surface, and a contact 45 that slides with the sliding elements 42 and 43 provided in the speed control unit 44. , 46, 47, 48.

  The contacts 45, 46, 47, 48 arranged on the sliding circuit board 13 are arranged in parallel and in an aligned state, and the variable contact 45 constituting a resistor in the form of a strip at the upper position, this variable contact 45, a sliding contact 46 formed of a conductive member in parallel with the same length, a control contact 47 formed of a conductive member parallel to the sliding contact 46 and not short of length, and the control contact 47 is formed of an auxiliary contact 48 formed of a conductive member in parallel with the same length.

  In the switching operation unit 25 having such a configuration, the rotation shaft 29 of the switching lever 26 is engaged with the rotation shaft engaging hole 23 of the case 12, and the switching contact piece 31 is connected to the switching contact of the sliding circuit board 13. The switching contact piece 31 makes the switching contacts 34a and 34b conductive by operating the switching knob 28, and a switching signal is generated.

  The speed control slider 42 is arranged so that the brush contacts both the sliding contact 46 and the variable contact 45 with respect to the contacts 45, 46, 47, 48 arranged on the sliding circuit board 13. When the switch slider 43 is brought into contact with the control contact 47 and the auxiliary contact 48 so that the brush comes into contact with each other, it functions as an auxiliary switch.

  In the speed control unit 44 having such a structure, when the sliding operation unit 15 is operated by the trigger lever 11 against the return spring 49, the speed control slider 42 and the switch slider 43 are connected to the sliding circuit. It slides in contact with the contacts 45, 46, 47, 48 of the substrate 13.

JP 2006-315119 A

However, in the case of the contact mechanism in the power tool switch described in the prior art, the contact portion is corroded by contact due to wear due to mechanical wear of the sliding contact portion, moisture or the like inside the switch, or invasion of corrosive gas. There is a problem of causing instability.
Therefore, in order to prevent malfunctions even if moisture enters the trigger switch, it is necessary to solve the problem of achieving a semi-permanent sliding life and environmental resistance by making contactless parts non-contact. Has a problem.

  In order to solve the above problems, the trigger switch for an electric tool of the present invention is configured as follows.

(1) The trigger switch for an electric tool is a trigger switch that is incorporated in a case and includes a sliding operation unit that moves in conjunction with the operation of the trigger lever. A permanent magnet is attached to a side surface of the speed control unit interlocked with the pulling operation, a magnetic circuit sensor is provided on a circuit board provided at a position facing the speed control unit, and the permanent magnet provided in the speed control unit is connected to the trigger lever. A signal generated by a change in the magnetic field applied to the magnetic field sensor when the speed controller linked to the pulling operation is moved in the pulling direction, and the speed of the motor is controlled based on the generated signal. is there.
(2) Further, a switching operation unit that controls normal rotation / reverse rotation of the motor by operation of the switching lever is provided, and the switching operation unit includes a shielding plate that protrudes from a side surface of the lever unit that is connected to the switching lever. The circuit board provided at a position facing the lever portion is provided with a photo interrupter, and by operating the switching lever, the optical path of the photo interrupter is blocked by the shielding plate, thereby rotating the motor forward and backward. The trigger switch for an electric tool according to (1), wherein the trigger switch is switched.
(3) The sliding operation unit further includes a shielding plate formed on the side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and a photo is provided on a circuit board provided at a position facing the speed control unit. An interrupter is provided, and when the speed control unit is moved in the pull-in direction, a motor rotation trigger is set based on a signal generated by blocking the optical path of the photointerrupter provided on the circuit board with the shielding plate. The trigger switch for an electric tool according to (1), which is characterized in that
(4) A switching operation unit that is incorporated in the upper position of the case and controls forward / reverse rotation of the motor by operating the switching lever;
A sliding operation unit built in the lower part of the case and moving in conjunction with the operation of the trigger lever,
A trigger switch with
The switching operation unit includes a shielding plate formed to project from a side surface of the lever unit provided continuously with the switching lever, and includes a photo interrupter on a circuit board provided at a position facing the lever unit,
By operating the switching lever, the forward and reverse rotations of the motor are switched by blocking the optical path of the photo interrupter with the shielding plate,
The sliding operation unit has a permanent magnet attached to a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and includes a magnetic field sensor on a circuit board provided at a position facing the speed control unit,
The permanent magnet provided in the speed control unit generates a signal due to a change in the magnetic field experienced by the magnetic field sensor when the speed control unit interlocked with the pull-in operation of the trigger lever is moved in the pull-in direction, Based on the generated signal, the speed of the motor is controlled,
The sliding operation unit further includes a shielding plate protruding from a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and a photo interrupter on a circuit board provided at a position facing the speed control unit. ,
The motor is a motor rotation trigger based on a signal generated by blocking the light path of the photo interrupter provided on the circuit board with the shielding plate when the speed control unit is moved in the pulling direction. Trigger switch for tools.

  The trigger switch for an electric tool according to the present invention realizes semi-permanent durability by changing the contact point of the trigger switch from a contact point to a contactless point, and is resistant to corrosion of the contact portion due to intrusion of moisture, dust, corrosive gas, etc. Environmental performance can be improved.

It is the whole perspective view which decomposed | disassembled and showed the trigger switch for electric tools which concerns on this invention. It is explanatory drawing which shows a circuit board equally. It is explanatory drawing which shows a circuit diagram equally. It is explanatory drawing which shows the relationship between the magnetic field sensor which comprises a linear position sensor, and a permanent magnet. It is explanatory drawing which shows the output from the magnetic field sensor which comprises a linear position sensor equally. It is the whole perspective view which decomposed | disassembled and showed the switch for electric tools in a prior art.

  An embodiment of a trigger switch for an electric tool according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the trigger switch for an electric tool according to the present invention incorporates a non-contact mechanism inside a box-like shape and transmits a sliding operation 15 from an external trigger lever 11. And a case 14 having an opening on the side surface, a cover 14 having a circuit board having a contactless mechanism on the inner side surface and closing the opening surface on the side surface of the case 12, and a trigger operated by a finger of a hand The lever 11 and a switching operation unit 25 that switches the forward / reverse rotation of the motor at the upper position of the case 12 are provided.

  The case 12 is formed in a box shape with an open side, and has the same shape as the upper lever guide portion 17 provided at the upper position for guiding the trigger lever 11 on the front side and the upper lever guide portion 17. A lower lever guide portion 18 provided at a lower position in the vertical direction is provided, and a speed control portion 20 that forms a sliding operation portion 15 in the depth direction sandwiched between the upper lever guide portion 17 and the lower lever guide portion 18 inside. Of the speed control unit storage chamber 19 and the switching lever 26 that constitutes the switching operation unit 25 at the upper position of the speed control unit storage chamber 19. Lever portion storage chamber for storing the lever portion 27A among the switching levers 26 constituting the moving shaft storage chamber 21 and the switching operation portion 25 continuously provided in the rotating shaft storage chamber 21 via a shielding member. Consisting of 2A.

  The cover 14 includes a board mounting portion 24 that mounts a rectangular circuit board 13A on the inner side wall.

  The switching lever 26 constituting the switching operation unit 25 includes a switching knob 28 that protrudes upward at the upper end of a trapezoidal lever portion 27A, and the switching lever 26 is pivotable at a substantially central position. The structure is provided with a pivot shaft 29 as a shaft, a lever portion 27A provided with a projectingly formed shielding plate 16 for generating a switching signal on the side surface of the rear end portion, and an oscillating spring 32 and an oscilloscope 33 at the rear end portion. It has become.

  The rotating shaft storage chamber 21 is a chamber for engaging the rotating shaft 29 of the switching lever 26 with the rotating shaft engaging hole 23, and is the switching lever 26 formed higher than the rotating shaft 29. The knob 28 is positioned outside the case 12.

  The lever portion storage chamber 22A is a room for storing the lever portion 27A including the shielding plate 16 of the switching lever 26, and the shielding plate 16 is disposed on the circuit board 13A attached to the cover 14 in this room. The shield plate 16 is shielded from the optical path of the photo interrupter 51 by the operation of the switching knob 28.

The sliding operation portion 15 is formed in a rod shape, and an O-ring and an external packing are attached to a free end portion. A sliding shaft 41 to which a trigger lever 11 can be attached, and a base side of the sliding shaft 41 and a side surface. A permanent magnet (magnet) 55 for applying a magnetic field to the magnetic field sensor 52 constituting the linear position sensor, and a speed control unit 20 for controlling the rotational speed of the motor;
In this structure, an auxiliary contact portion 57 having a shielding plate 56 formed to project a start signal for driving the motor is provided on the lower side surface to which the permanent magnet 55 is attached.

  The speed control unit 20 includes a circuit board 13A that is connected to the sliding shaft 41, includes a permanent magnet 55 that interlocks with the movement of the sliding shaft 41, and includes a magnetic field sensor 52 that forms a linear position sensor. Yes.

  As shown in FIG. 2, the circuit board 13A has a structure in which a non-contact sensor is attached, and a photo interrupter 51 for controlling the rotation direction of the motor is attached to the upper end of the circuit board 13A. A magnetic field sensor 52 constituting a linear position sensor is attached at a substantially central position, a photo interrupter 58 for controlling the rotation start of the motor is attached to the lower part thereof, and a connector 53 is attached to the lower end. .

The photo interrupter 51 attached to the circuit board 13A switches the rotation of the motor by operating a so-called switching knob 28. By switching the shielding plate 16 so as to block the optical path of the photo interrupter 51, the switching is performed. When the lever 26 is operated, the shielding plate 16 blocks the optical path of the photo interrupter 51, thereby turning off the phototransistor.
As shown in FIGS. 2 and 3, the photo interrupter 51 is provided with a light emitting diode in a portion corresponding to one arm of a housing formed in a U-shape, and a phototransistor that is turned on by inputting a light beam from the light emitting diode. Is provided in a portion corresponding to the other one arm facing the light emitting diode. Then, by inserting a shielding plate for blocking the light beam between the opposed light emitting diode and the phototransistor, the phototransistor is controlled to be turned on / off to switch the rotation direction of the motor.

The magnetic field sensor 52 constituting the linear position sensor attached to the circuit board 13 </ b> A has a so-called permanent magnet 55 attached to the speed control unit 20 along the pull-in operation of the trigger lever 11. Changes in the magnetic field experienced by the magnetic field sensor 52 are detected by moving in the direction.
The linear position sensor includes a so-called permanent magnet 55 and a magnetic field sensor 52. The permanent magnet 55 and the magnetic field sensor 52 can move linearly while facing each other along the movement path. The magnetic field sensor 52 is permanent. It is arranged in the magnetic field of the magnet 55.
The magnetic field sensor 52 generates an output signal determined by the direction of the magnetic field, and converts the output signal of the magnetic field sensor 52 into a control signal corresponding to a linear movement path between the magnetic field sensor 52 and the permanent magnet 55, thereby triggering. The speed control accompanying the pull-in operation of the lever 11 can be performed.
Thus, the output signal from the magnetic field sensor 52 is determined by the direction of the magnetic field flowing through the magnetic field sensor 52.
Therefore, as shown in FIG. 4, if the moving direction of the permanent magnet 55 that generates a magnetic field with respect to the magnetic field sensor is moved in parallel and linearly with respect to the magnetic field sensor 52, the speed control by the change of the magnetic field can be performed. It can be carried out.

  The photo interrupter 58 attached to the circuit board 13A serves as a trigger for rotating the motor by the so-called auxiliary contact portion 57 interlocked with the pull-in operation of the trigger lever 11, and blocks the optical path of the photo interrupter 58. By disposing the shielding plate 56, when the trigger lever 11 is operated, the shielding plate 56 blocks the optical path of the photo interrupter 58 and the phototransistor is turned off.

  The photointerrupter 58 has the same structure as the photointerrupter 51. As shown in FIGS. 2 and 3, a light emitting diode is provided at a portion corresponding to one arm of a housing formed in a U-shape. A phototransistor that is turned on when a light beam from the diode is input is provided in a portion corresponding to the other arm facing the light emitting diode. Then, by inserting a shielding plate for blocking light between the light emitting diode and the phototransistor facing each other, the phototransistor is controlled to be turned on / off to control the rotation start of the motor.

The graph shown in FIG. 5 shows the output signal from the magnetic field sensor 52 that accompanies the pulling operation (stroke) of the trigger lever and the control signal generated by this output signal.
The meaning of this graph is that the permanent magnet 55 moves in a linear direction according to the operation amount of the trigger lever 11 and the magnetic field generated from the permanent magnet 55 crosses the magnetic field sensor 52 to generate an output signal. This is a graph showing how to do this. This output signal No. 1 has a maximum density across the magnetic field when the permanent magnet 55 is closest to the magnetic field sensor 52. Therefore, the signal is increased accordingly, and the peak that is the maximum when the stroke is at the center position as a whole. It becomes a shape signal. By capturing the characteristics of this signal and generating a control signal, the speed can be controlled by a signal corresponding to the stroke.
Further, since the control signal can be easily changed by a program, it is possible to easily realize motor control such as straight lines and curves.

  Provided is a trigger switch that realizes a semi-permanent sliding life and environmental resistance by making contactless parts non-contact so that malfunction does not occur even if moisture enters the inside of the trigger switch.

DESCRIPTION OF SYMBOLS 11 Trigger lever 12 Case 13A Circuit board 14 Cover 15 Sliding operation part 16 Shielding plate 17 Upper lever guide part 18 Lower lever guide part 19 Speed control part storage chamber 20 Speed control part 21 Rotating shaft storage room 22A Lever part storage room 23 Rotating shaft engaging hole 24 Substrate mounting portion 25 Switching operation portion 26 Switching lever 27A Lever portion 28 Switching knob 29 Rotating shaft 32 Oshibo spring 33 Oshibo 41 Slide shaft 51 Photo interrupter 52 Magnetic field sensor 53 Connector 55 Permanent magnet 56 Shielding plate 57 Auxiliary contact 58 Photo interrupter

Claims (4)

A trigger switch with a sliding operation part built in the case and moving in conjunction with the operation of the trigger lever,
The sliding operation unit has a permanent magnet attached to a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and includes a magnetic field sensor on a circuit board provided at a position facing the speed control unit,
The permanent magnet provided in the speed control unit generates a signal due to a change in the magnetic field experienced by the magnetic field sensor when the speed control unit interlocked with the pull-in operation of the trigger lever is moved in the pull-in direction, A trigger switch for an electric tool, wherein the motor speed is controlled based on the generated signal. In addition, it has a switching operation part that controls forward and reverse rotation of the motor by operating the switching lever.
The switching operation unit includes a shielding plate formed to project from a side surface of the lever unit provided continuously with the switching lever, and includes a photo interrupter on a circuit board provided at a position facing the lever unit,
2. The electric tool trigger according to claim 1, wherein the motor is switched between normal rotation and reverse rotation by blocking the optical path of the photo interrupter with the shielding plate by operating the switching lever. switch. The sliding operation unit further includes a shielding plate protruding from a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and a photo interrupter on a circuit board provided at a position facing the speed control unit. ,
The motor rotation trigger is based on a signal generated by blocking the optical path of the photo interrupter provided on the circuit board with the shielding plate when the speed control unit is moved in the retracting direction. Item 2. A trigger switch for an electric tool according to Item 1. A switching operation unit incorporated in the upper part of the case and controlling the forward / reverse rotation of the motor by operating the switching lever;
A sliding operation unit built in the lower part of the case and moving in conjunction with the operation of the trigger lever,
A trigger switch with
The switching operation unit includes a shielding plate formed to project from a side surface of the lever unit provided continuously with the switching lever, and includes a photo interrupter on a circuit board provided at a position facing the lever unit,
By operating the switching lever, the forward and reverse rotations of the motor are switched by blocking the optical path of the photo interrupter with the shielding plate,
The sliding operation unit has a permanent magnet attached to a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and includes a magnetic field sensor on a circuit board provided at a position facing the speed control unit,
The permanent magnet provided in the speed control unit generates a signal due to a change in the magnetic field experienced by the magnetic field sensor when the speed control unit interlocked with the pull-in operation of the trigger lever is moved in the pull-in direction, Based on the generated signal, the speed of the motor is controlled,
The sliding operation unit further includes a shielding plate protruding from a side surface of the speed control unit interlocked with the pull-in operation of the trigger lever, and a photo interrupter on a circuit board provided at a position facing the speed control unit. ,
The motor is a motor rotation trigger based on a signal generated by blocking the light path of the photo interrupter provided on the circuit board with the shielding plate when the speed control unit is moved in the pulling direction. Trigger switch for tools.

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