JP4531367B2 - Screwdriver bit and electric screwdriver, manual screwdriver - Google Patents

Description

  The present invention relates to an electric driver, a manual driver, and a driver bit that can be suitably used for installation work or indoor wiring work when a power meter is newly installed or replaced, for example.

In recent years, when power meter installation work and indoor wiring work are performed, it has been demanded that the power meter be used without a power failure so as not to hinder the use of power in ordinary households. For this reason, electric screwdrivers and manual driver screwdriver bits for tightening or removing the fixing screw that secures the lead wire or crimping terminal are used to prevent troubles such as electric shock. The outer peripheral surface except for is covered with an electrically insulating material. Examples of such a driver bit include those for manual drivers in which an electrically insulating heat-shrinkable tube is attached to the outer peripheral surface of the bit shaft portion and brought into close contact by heat shrinkage (for example, see Patent Document 1). There is known a device for an electric screwdriver in which an electrically insulating heat-shrinkable tube is attached to the outer peripheral surface of a shaft portion and adhered by heat shrinkage (for example, see Patent Document 2). In addition, conventionally, there is a driver bit in which a bit shaft portion is coated with a resin.
Japanese Utility Model Publication No. 55-129776 Japanese Patent Laid-Open No. 9-225849

  However, the conventional driver bit of the electric screwdriver has the following problems because the insulating coating member is closely fixed so as to rotate integrally with the bit shaft portion. That is, in the power meter 40 shown in FIG. 5A, a large number of fixing screws 41 are arranged at very small intervals, and the arrangement pitch P of the fixing screws 41 is about 20 mm in a narrow case. Become. Therefore, when tightening the fixing screw 41 provided with such an arrangement pitch P, when the driver bit is inserted into the screw head with a relatively large inclination with respect to the axial direction of the fixing screw 41, the bit is Two adjacent fixing screws may be electrically short-circuited by the tip portion including the bit portion at the tip which is not covered with the insulating coating member in the shaft portion. Therefore, as shown in FIG. 5 (b) showing the tightening state of the fixing screw 41, the conventional driver bit 42 has an insulating coating on the entire outer peripheral surface of the bit shaft portion 43 leaving a portion of about 8 mm from the tip of the bit portion 44. The member 45 is covered.

  However, when the screw tightening operation at the location shown in FIG. 5B is performed, when the fixing screw 41 is screwed into the screw hole 47 as the driver bit 42 rotates, the screwdriver bit 42 is fixed to the fixing screw 41. It is difficult to accurately hold in the axial direction, and when the driver bit 42 is slightly inclined with respect to the axial direction of the fixing screw 41, the distal end portion of the insulating coating member 45 that rotates integrally with the bit shaft portion 43 is fixed to the fixing screw. If it contacts the opening edge part of the mounting recess 46 and such contact state is repeated, the tip part of the insulation coating member 45 will be worn out and the malfunction that the bit axial part 43 will be exposed will generate | occur | produce.

  The present invention has been made in view of the above-described conventional problems, and even when the tip part contacts other parts such as the opening edge of the fixing screw mounting recess during use, the insulation coating member is surely worn. An object of the present invention is to provide a driver bit that can prevent and retain required insulation performance for a long period of time.

In order to achieve the above object, a driver bit according to a first aspect of the present invention includes a bit shaft portion that is integrally provided with a bit portion at a tip thereof, and a shaft that is rotatable on an outer peripheral surface of the bit shaft portion excluding the bit portion. And an insulating cylinder portion that is held in a state of being prevented from being detached by the bit portion and a drive proximal end portion on the proximal end side of the bit shaft portion, and the insulating cylinder portion extends along the cylinder center direction of the cylinder body. A longitudinally cut tube and an exterior insulating tube, and the longitudinally cut tube is inserted and covered from a cutting opening with respect to an outer peripheral surface of the bit shaft portion, and the exteriorly insulated tube is covered with the longitudinally divided tube. It is characterized in that it is formed so as to be fitted onto the outer peripheral surface .

The invention of claim 2 provides an electric screwdriver in which the drive base end portion of the driver bit configured as described above is detachably connected to the rotary connecting portion of the electric tool.

The invention according to claim 3 provides a manual driver in which the drive base end portion of the driver bit configured as described above is fixed to the grip portion.

According to the first aspect of the present invention, when the tip of the insulating cylinder part is brought into contact with the opening edge of the fixing screw mounting recess and the like when it is tilted with respect to the axial direction of the fixing screw during use, it rotates together with the bit shaft part. Since the insulating cylinder portion that has been fitted is rotatably fitted with respect to the bit shaft portion, the rotation is stopped by the contact portion, and the bit shaft portion is idle with respect to the insulating cylinder portion. As described above, since the insulating cylinder portion does not rub against the contact member, it is reliably prevented from being worn, and the entire outer peripheral surface of the bit shaft portion is always covered and insulated. In addition, the vertically divided tube can be easily attached in a state where a gap is provided with respect to the outer peripheral surface of the bit shaft portion.

According to the second aspect of the present invention, although the fixing screw can be efficiently tightened while being attached to the electric tool and rotated at a high speed, the insulating cylinder portion is formed on the opening edge of the fixing screw mounting recess, etc. In the case of contact, it is possible to reliably prevent wear due to rubbing by keeping the insulating cylinder portion stationary with respect to the bit shaft portion rotating at high speed.

In the invention of claim 3 , since the insulating cylinder portion does not rub against the contact member, it is reliably prevented from being worn, and the entire outer peripheral surface of the bit shaft portion is always covered securely. A manual screwdriver that can be insulated can be provided.

1A and 1B show a driver bit according to a reference example of the present invention, in which FIG. 1A is a side view, FIG. 1B is an enlarged cross-sectional view taken along line AA in FIG. . In this reference example , a power tool is illustrated. In this driver bit, an insulating cylinder portion 3 made of a cylindrical insulating tube is fitted on the outer peripheral surface of the bit shaft portion 2 with the bit portion 1 integrally formed at the tip, excluding the bit portion 1, and the bit shaft portion. After a drive base end portion 4 formed in a shape connectable to a rotation connecting portion of an electric power tool, which will be described later, is externally fitted to a small-diameter mounting shaft portion 7 integrally projecting from the base end side of 2 Has been fixed.

The insulating cylinder portion 3 is made of a resin such as vinyl chloride, fluorine resin ( Teflon (registered trademark) ), nylon, or the like, and is formed in a cylindrical shape having an inner diameter slightly larger than the outer diameter of the bit shaft portion 2. . Therefore, as clearly shown in (b), there is a slight gap 8 between the outer peripheral surface of the bit shaft portion 2 and the inner peripheral surface of the insulating cylinder portion 3 fitted thereto. The insulating cylinder portion 3 is rotatably held with respect to the bit shaft portion 2 and is prevented from coming off from both sides by the bit portion 1 and the drive base end portion 4. In this reference example , a minus bit is illustrated as the bit part 1, but a plus bit may be used.

As shown in (c), the driver bit is welded and fixed in a state in which the drive base end portion 4 is fitted to the mounting shaft portion 7 after the insulating tube portion 3 is externally fitted to the bit shaft portion 2. It is assembled by the procedure. Therefore, the driver bit of this reference example can be easily assembled into a configuration in which the insulating cylinder portion 3 can be freely rotated by providing a gap with respect to the bit shaft portion 2.

  As shown in FIG. 2, the driver bit is used by being connected in a state where the drive base end portion 4 is fitted into the rotary connecting portion 10 of the electric tool 9 and integrally rotated. When the electric power tool 9 grips the grip portion 11 and presses the trigger switch 12 with a finger, a motor (not shown) built in the main body portion 13 operates by receiving a drive power supply from the battery 14, The rotation of the motor is transmitted to the drive base end portion 4 of the driver bit via the rotary connecting portion 10, and the bit shaft portion 3 having the bit portion 1 at the tip is rotationally driven, and the bit portion at the tip of the bit shaft portion 2 is moved. Insert the fixing screw into the screw head and tighten the fixing screw.

  During the tightening operation of the fixing screw, when the driver bit is inclined with respect to the axial direction of the fixing screw and the tip portion of the insulating cylinder 3 comes into contact with the opening edge of the fixing screw mounting recess, the screw is rotated at a high speed. Since the insulating cylinder portion 3 that has co-rotated with the bit shaft portion 2 is rotatably fitted to the bit shaft portion 2, the rotation is stopped by the contact portion, and the bit shaft portion 2 becomes stationary. The insulating cylinder portion 3 is idled. As described above, since the insulating cylinder portion 3 does not rub against the contact member, it is reliably prevented from being worn, and the entire outer peripheral surface of the bit shaft portion 2 is always reliably covered and insulated. To do.

3A and 3B show a driver bit according to the first embodiment of the present invention, in which FIG. 3A is a side view, FIG. 3B is an enlarged cross-sectional view taken along line BB in FIG. It is a side view. In the figure, the same or equivalent parts as in FIG. In this embodiment, instead of the insulating cylinder portion 3 made of the insulating tube of the reference example , the insulating cylinder portion 17 is a vertically divided tube 18 in which the cylinder is cut along a cutting line 18a in the cylinder center direction, The structure is provided with an exterior insulating tube, and is different from the reference example in the configuration in which the drive base end portion 4 is integrally formed with the bit shaft portion 2.

  As shown in (c), the insulating cylinder portion 17 covers the outer insulating tube 19 on the bit portion 1 side after covering the longitudinal tube 18 by inserting it into the outer peripheral surface of the bit shaft portion 2 from the cut opening. To the outer circumferential surface of the vertically divided tube 18. As shown in (b), the vertically divided tube 18 is covered with the bit shaft portion 2 in a wound state in which both side cut ends are overlapped with each other, as shown in FIG. In this embodiment, the vertically divided tube 18 is formed by cutting an insulating tube made of a fluororesin (trade name: Teflon) in the cylinder center direction, and the exterior insulating tube 18 is formed using urethane as a material.

  An example of the dimensions of each member is as follows. When the diameter of the bit portion 1 is 6.0 mm and the diameter of the bit shaft portion 2 is 4.0 mm, the longitudinal tube 18 has an inner diameter of 5.0 mm and an outer diameter. A fluororesin tube having a diameter of 6.0 mm cut along the cutting line 18a is used, and the outer insulating tube 19 is a urethane tube having an inner diameter of 5.7 mm and an outer diameter of 8 mm.

  Then, as shown in FIG. 3 (b), the vertically divided tube 18 is fitted so as to wrap around the outer peripheral surface of the bit shaft portion 2, and the inside of the both end overlapping portion and the outside of the bit shaft portion 2 are A gap 31 is formed between the two. The outer diameter of the vertically divided tube 18 in this winding state is about 5.5 mm, which is slightly smaller than the outer diameter of the outer insulating tube 19 5.7 mm. After the vertically divided tube 18 is in the above-described winding state, the exterior insulating tube 19 is externally fitted from the bit portion 1 to the bit shaft portion 2. At this time, the exterior insulation tube 19 is made of urethane and has a slight elasticity, so that it can be deformed into a diameter-expanded state and the bit part 1 can be inserted therethrough. When the exterior insulation tube 19 is externally fitted to the longitudinal tube 18, a slight gap (not shown) is generated between the longitudinal tube 18 and the exterior insulation tube 19. Thereby, the vertically divided tube 18 and the exterior insulating tube 19 are held rotatably with respect to the bit shaft portion 2.

Therefore, when the driver bit of this embodiment is used by being attached to the electric power tool 9 shown in FIG. 2, the exterior insulating tube 19 and the vertically divided tube 18 are held rotatably with respect to the bit shaft portion 2. Therefore, as in the case of the reference example , when the driver bit is inclined with respect to the axial direction of the fixing screw and the distal end portion of the outer insulation tube 19 comes into contact with other things such as the opening edge of the fixing screw mounting recess The outer insulating tube 19 is stopped by rotation at the contact portion with respect to the bit shaft portion 2 rotated at a high speed, so that only the bit shaft portion 2 is idling. Therefore, in this driver bit as well, as in the first embodiment, since the outer insulating cylinder portion 17 does not rub against the contact member, it is reliably prevented from being worn, and the bit shaft The entire outer peripheral surface of the part 2 is always reliably covered and insulated.

  In the above-described driver bit, the outer diameter of the outer insulating tube 19 is slightly larger than the outer shape of the bit portion 1, but by forming the distal end portion of the outer insulating tube 19 on the tapered surface 22, the outer diameter of the outer insulating tube 19 is relatively large. The insulating tube 19 is designed so that the tip of the bit portion 1 does not become difficult to see.

FIG. 4 is a side view showing a manual driver according to the second embodiment of the present invention. This manual driver connects and fixes the drive base end portion 4 of the driver bit of the first embodiment to the grip portion 23. It is a thing. Therefore, this manual driver can obtain the same effect as described in the first embodiment when used.

  In each of the above embodiments, the bit portion 1 is illustrated as a minus type, but a plus type may be used as a matter of course.

The driver bit which concerns on the reference example of this invention is shown, (a) is a side view, (b) is the expanded sectional view cut | disconnected by the AA line of (a), (c) is an exploded side view. The side view which shows the electric screwdriver which attached the driver bit same as the above. The driver bit which concerns on the 1st Embodiment of this invention is shown, (a) is a side view, (b) is the expanded sectional view cut | disconnected by the BB line of (a), (c) is an exploded side view. The side view which shows the driver bit which concerns on the 2nd Embodiment of this invention. (A) is a front view which shows the electric power meter which can be suitably constructed with a driver bit, (b) is sectional drawing which shows the fastening state of the fixing screw by a driver bit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bit part 2 Bit shaft part 3 Insulation cylinder part 4 Drive base end part 7 Mounting shaft part 9 Electric tool 10 Rotation connection part 17 Insulation cylinder part 18 Vertically split tube 19 Exterior insulation tube

Claims (3)

A bit shaft portion integrally provided with a bit portion at the tip;
An insulating cylinder portion that is rotatably fitted to an outer peripheral surface of the bit shaft portion excluding the bit portion and is held in a state of being prevented from being detached by the bit portion and a drive base end portion on the base end side of the bit shaft portion. And the insulating tube portion includes a vertically divided tube obtained by cutting the cylindrical body along the cylinder center direction, and an exterior insulating tube, and the vertically divided tube is cut with respect to the outer peripheral surface of the bit shaft portion. A driver bit , wherein the outer insulating tube is formed by being fitted onto the outer peripheral surface of the vertically divided tube . An electric screwdriver in which the drive base end portion of the driver bit according to claim 1 is detachably connected to a rotary connecting portion of an electric tool. A manual screwdriver in which a drive base end portion of the driver bit according to claim 1 is fixed to a grip portion.

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