JP2002307325A - Electric power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the optimal lighting even if a ring body is provided in a front end. SOLUTION: A small diameter part 8 is extended from a rear end of a change ring 6 held by a housing 2 freely to turn, and a positive and a negative electrode plates 11 and 11 are fitted in the small diameter part 8 at nearly half-circumference each other, and a positive and a negative terminal plates 17 and 17 provided in the housing 2 are brought in contact with the peripheral surface of the electrode plates 11 and 11. A front end of the change ring 6 is formed with a recessed groove 20 opened forward, and LED 22 and 22 are arranged, directed forward, on a substrate 21 housed in the groove 20. Connector terminals 24 and 24 of the LED 22 and 22 passed through the inside of the change ring 6 from the substrate 21 are electrically connected to the electrode plates 11 and 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power tool such as a screwdriver provided with a ring for selecting functions at a front end of a housing.

[0002]

2. Description of the Related Art For example, a screwdriver is provided with a clutch mechanism for interrupting torque transmission to a spindle when a predetermined load is applied to the spindle, and at the front end of a housing, an upper limit of a torque at which the clutch mechanism operates is adjusted. A change ring is provided so as to be rotatable within a predetermined angle.

[0003]

By the way, there is known a power tool provided with an illuminator (for example, a light emitting diode) for illuminating a portion to be processed in order to improve the usability in a dark place. This illuminator is preferably provided at the front end of the housing closest to the spindle in the case of a gun-shaped power tool whose spindle projects forward. However, in the above screwdriver, since the change ring is provided at the front end, it is provided along the housing on the side surface of the housing.

Accordingly, an object of the present invention is to provide a power tool capable of providing an illuminating body at an optimum position without any trouble even if a ring body is provided at a front end of a housing.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a ring body is provided with an illuminating body capable of illuminating the front, and a rear end of the ring or a front end of the housing. One of the parts is provided with arc-shaped positive and negative electrode plates along the circumferential direction of the ring body and the concentric circle, and the other is provided with a positive and negative terminal plate that is in contact with the corresponding electrode plate. The power supply in the housing is electrically connected to the electrode plate or the terminal plate, and the electric connection between the electrode plate and the terminal plate is maintained regardless of the rotation of the ring body. Thus, the lighting body can be turned on. According to the invention described in claim 2, in addition to the object of claim 1, when the illuminating body is a light emitting diode, even if the polarity of the electrode plate and the terminal plate is reversed by the rotation of the change ring, the light is emitted. In order to maintain the lighting of the diode, a diode bridge is provided between the light emitting diode and the electrode plate.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a front end portion of a screw driver 1 as an example of an electric tool. A housing 2 in which a vertically divided half housing is assembled is provided.
A gear case 3 in which a planetary gear reduction mechanism is provided is accommodated, and torque can be transmitted to a spindle 4 protruding forward. Here, when a predetermined load is applied to the spindle 4, A clutch mechanism for interrupting the transmission of torque to the spindle 4 is also provided. That is, by providing a final stage internal gear of the planetary gear reduction mechanism rotatably in the gear case 3 and providing a coil spring 5 for pressing and fixing the internal gear from the front, the upper limit torque at which the internal gear runs idle Can be set by the pressing force of the coil spring 5. The pressing force of the coil spring 5 can be changed by a change ring 6 as a ring body rotatably mounted on the front end of the housing 2. This is achieved by rotating the change ring 6 to axially move a spring holder (not shown) that holds the front end of the coil spring 5 in the change ring 6 and changes the axial length of the coil spring 5. You.

As shown in FIGS. 2 and 3, the change ring 6 is a cylindrical body through which the spindle 4 penetrates and a two-stage diameter through hole 7 having a small diameter at the front is formed concentrically. Small diameter part 8
Is extended. The small diameter portion 8 is rotatable with respect to the housing 2 by fitting a ridge 10 projecting from the inner surface of each half housing of the housing 2 into a ring-shaped connection groove 9 provided on the outer surface. Is to be gripped. In the small-diameter portion 8, positive and negative electrode plates 11 having an L-shaped cross section are provided around the outer periphery of the front portion of the connection groove 9 with the gap 1 for insulation.
It is fitted in an arc shape along the small diameter portion 8 except for 2, 12,
At the center of the inner peripheral side of each of the electrode plates 11, connection pieces 13 inserted into the back of the connection groove 9 are provided in a protruding manner. Further, a plurality of recesses 14, 14,..., Which can be engaged with a leaf spring (not shown) provided in the housing 2 in an assembled state with the housing 2 at regular intervals, are provided on the outer periphery of the rear end of the small diameter portion 8. Have been.

On the other hand, the gear case 3
A pair of projections 15 are provided on the side surface of the gear case 3 at point-symmetric positions about the axis of the gear case 3.
The positive and negative terminal plates 1 electrically connected to the power supply circuit of the screw driver 1 by lead wires 16
The base ends of 7, 17 are inserted. Further, ribs 19, 19 are provided at positions corresponding to the terminal plates 17, 17 on the inner surface of the housing 2.
19 are protruded, and the ribs 19, 19
The terminal plates 17, 17 are fixed to the side surfaces of the gear case 3 by holding the terminals 7, 17 from the outside. Furthermore, terminal plate 1
The free ends 18, 18 in front of 7, 17 are bent so as to be in contact with the peripheral surfaces of the electrode plates 11, 11 when the change ring 6 is assembled.

At the front end of the change ring 6, a ring-shaped groove 20 centering on the through hole 7 is formed so as to open to the front surface, and the groove 20 has the same shape as the bottom surface of the groove 20. The substrate 21 is accommodated therein, and light-emitting diodes (hereinafter, referred to as “LEDs”) 22, 22 are arranged on the substrate 21 at symmetrical positions with the through hole 7 interposed therebetween. A pair of through holes 23, 23 extending from the groove 20 to the connection piece 13 of each electrode plate 11 are formed in the change ring 6 in the axial direction, and a connection extending from the substrate 21 into the through holes 23, 23. The terminals 24 are inserted and soldered to the connection pieces 13. However, the LEDs 22, 22 are shown in FIG.
As shown in the circuit diagram of FIG.
In 0, the LEDs 22 are connected to the connection terminals 24 via a diode bridge 25 also disposed on the substrate 21 so that a forward voltage is always applied to the LEDs 22 connected in parallel. In the figure, reference numeral 26 denotes a battery serving as a power source of the screw driver 1, 27 denotes a switch,
Is resistance. The front surface of the groove 20 is closed by a transparent plate 29 of the same shape and made of synthetic resin.

[0010] In the screwdriver 1 configured as described above, the LEDs 22 and 22 are connected to the connection terminals 24 and 2.
4, since it is connected to the battery 26 via the electrode plates 11, 11 and the terminal plates 17, 17, when the switch 27 is turned on, the electric circuit shown in FIG.
22 lights up. Therefore, the front of the change ring 6 is illuminated, and the tip of a driver bit or the like mounted on the spindle 4 can be brightened. On the other hand, when adjusting the torque of the clutch mechanism in the screw driver 1, by rotating the change ring 6 to a predetermined adjustment position, the pressing force of the coil spring 5 changes as described above to set an arbitrary upper limit torque. be able to. At this time, the electrode plates 11, 11 also rotate in accordance with the rotation of the change ring 6, but the free ends 18, 18 of the terminal plates 17, 17 relatively slide against the peripheral surfaces of the electrode plates 11, 11 to establish electrical connection. In order to maintain, the lighting of the LEDs 22, 22 is maintained.

The rotation angle of the change ring 6 for torque adjustment is about 330 °. Therefore, when the rotation of the change ring 6 exceeds 180 °, the electrode plates 11, 11 in contact with the terminal plates 17, 17 move to the adjacent electrode plates, and the positive and negative polarities reverse as shown in FIG. , But LE by the diode bridge 25
Since the direction of energization to D22 and D22 does not change, LED2
Lighting of 2,22 is maintained. Further, as described above, the rotation position of the change ring 6 is determined by the concave portion 1 formed in the small diameter portion 8.
The click action of the leaf springs engaging the springs 4 and 14 is set stepwise at predetermined angles.
Since the click positions are set so as not to correspond to the gaps 12, 11 between the terminals 1, 11, the terminal plates 17, 17 are not located in the gaps 12, 12 at any rotational position of the change ring 6.

As described above, according to the screw driver 1, it is possible to provide the LEDs 22, 22 at positions optimal for illumination, even if the screw ring 1 is provided with the change ring 6 for rotating. Of course, it does not affect the torque adjustment by the change ring 6. Therefore, the front of the change ring 6 can be suitably illuminated, and the convenient screw driver 1 can be obtained. Here, since the diode bridge 25 is provided between the LEDs 22, 22 and the electrode plate 11, the LEDs 22, 22 are always turned on regardless of the reversal of the polarity of the electrode plates 11, 11 due to the rotation of the change ring 6. It can be maintained.

In the above-described embodiment, the reversal of the polarity caused by the rotation of the change ring 6 is dealt with by the diode bridge 25. However, as shown in FIGS.
If D22 and D22 are connected so that the energizing directions are opposite to each other, one of the LEs is always used regardless of the polarity reversal.
D22 will light up. Of course, if further illumination is required, two LEDs may be connected in parallel in one direction. In addition, the illuminating body is not limited to the LED, and can be appropriately adopted as long as it can be mounted on a ring body such as a miniature bulb or a tube bulb, such as a change ring. In addition to utilizing the above, a concave portion may be partially formed at a location where an LED or the like is provided. It should be noted that a diode bridge is not required for an illuminating body such as a miniature light bulb that does not need to consider the direction of conduction.

On the other hand, in the above-described embodiment, the electrode plate formed in the circumferential direction is provided at the rear end of the ring body, and the terminal plate is provided at the front end of the housing. At the front end, a terminal plate may be provided at the rear end of the ring body. Further, a structure in which the terminal plate slides on the inner periphery of the electrode plate may be adopted. In addition, the present invention is applicable not only to a screwdriver having a change ring for adjusting torque but also to a driver drill having a ring body for mode switching at a front end of a housing.

[0015]

According to the first aspect of the present invention, it is possible to provide an illuminating body at an optimal position for illumination, even if it has a ring body. Of course, the adjustment by the ring body is not affected. Therefore, it is possible to suitably illuminate the front of the ring body, and to obtain an easy-to-use power tool. According to the invention described in claim 2, according to claim 1
In addition to the above effects, the lighting body is a light emitting diode, and a diode bridge is provided between the light emitting diode and the electrode plate, so that the light emitting diode can be always turned on regardless of the polarity reversal due to the rotation of the ring body. Become.

[Brief description of the drawings]

FIG. 1A is an explanatory view of a front end portion of a screwdriver as viewed from above. (B) It is explanatory drawing which looked at the front end part of the screw driver from the side surface. (C) It is explanatory drawing which looked at the front end part of the screwdriver from the lower part.

FIG. 2A is a front view of a change ring. (B) It is a side view of a change ring. (C) It is a rear view of a change ring.

FIG. 3A is a front view of a change ring mounted on a housing. (B) It is a sectional view on the AA line. (C) It is BB sectional drawing.

FIG. 4A is an electric circuit diagram of a screw driver. (B) is an electric circuit diagram showing a state in which the polarity is reversed.

FIG. 5A is a modified example of the electric circuit diagram. FIG. 3B is an electric circuit diagram showing a state in which the polarity is reversed.

[Explanation of symbols]

1. Screwdriver, 2. Housing, 4.
Spindle, 6 change ring, 8 small diameter part, 1
1 ··· Electrode plate, 17 ··· Terminal plate, 18 ··· Free end, 20
..Grooves, 21..substrate, 22..LED, 25..diode bridge.

Claims (2)

[Claims] 1. A power tool having a ring for function selection mounted at a front end of a housing so as to be rotatable within a predetermined angle, wherein the ring is provided with an illuminator capable of illuminating the front, One of the rear end of the ring body and the front end of the housing is provided with an arc-shaped positive / negative electrode plate extending in the circumferential direction of a circle concentric with the ring body, and the other positive / negative electrode contacting the corresponding electrode plate. And the power supply in the housing is electrically connected to the electrode plate or the terminal plate on the housing side, respectively, and the lighting body is electrically connected to the electrode plate or the terminal plate on the ring side. An electric tool characterized in that the lighting unit can be turned on by maintaining the electrical connection between the electrode plate and the terminal plate regardless of the rotation of the body. 2. The power tool according to claim 1, wherein the illuminating body is a light emitting diode, and a diode bridge is provided between the light emitting diode and the electrode plate or terminal plate on the ring body side.