JP3091663B2 - bit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bit for a screw tightening tool used for tightening various screws.

[0002]

2. Description of the Related Art Conventionally, bits have been widely used in various automatic screw tightening machines or manual screw tightening tools. There are various types of bits depending on the shape of the screw head, particularly the shape of the drive hole, but recently, as shown in FIG. 4, the bit has a tip end surface 50a substantially coinciding with the screw head. A bit 50 has been developed in which an engaging portion 50b protruding from the axial center position of the tip end surface 50a by the depth of the screw driving hole is integrally formed and magnetized.

[0003]

However, according to various standards such as the JIS standard, a certain dimensional error is provided in the dimensions of the head of the screw, the dimensions of the drive hole, and the like. The manufactured screw has a considerable variation in dimensions such as a head shape and a drive hole shape. According to the above-mentioned bit, in view of the fact that the tip end surface and the engaging portion are integrally formed,
It is impossible to cope with the dimensional error of this screw, and there are problems such as the screw drive hole being shallow, the tip surface not matching the screw head upper surface, and the screw holding being unstable. In addition, even if the screw drive hole is larger than the engagement part and the tip surface matches the screw head upper surface, the engagement part does not engage with the drive hole, and the screw is tightened in that state to perform the screw drive hole. In such a case, a problem such as breakage of the screw occurs, and it is impossible to reliably hold the originally intended screw.

[0004] The present invention has been made in view of the above problems, and has as its object to provide a bit capable of securely holding a screw and performing a good tightening operation.

[0005]

To achieve the above object, according to an aspect of the bit of the present invention, the magnetic permeability than the screw to chromatic vital nonmagnetic or engaging an engaging portion for engaging the drive screw holes
A bit body made of any of low materials is provided, and a magnetized member slidable along the bit body near the engagement portion of the bit body is provided, and the magnetized member is included and slid integrally. Possible screw head face opposite this
A protective member which is formed into a shape along the surface provided with the protective unit
The tip of the engaging part of the bit body is always
It is characterized by being configured to protrude by a fixed amount. In addition,
The protective member preferably has an outer diameter equal to or less than the screw head diameter.
Good.

[0006]

In the above-mentioned bit, when the screw driving hole is engaged with the engaging portion, the protection member and the magnetic member slide along the bit main body in accordance with the depth of the screw driving hole, and the screw is driven. Engage the engaging portion with the hole securely. At this time, if the bit main body is formed from a non-magnetic material or a material having a lower magnetic permeability than the screw material, the operation of the magnetized member with respect to the bit main body can be smoothed and the operation range can be expanded. Also, by forming the protective member to an outer diameter equal to or smaller than the head diameter of the screw, for example, a work in which a screw hole is provided at the bottom of a bottomed hole having a diameter slightly larger than the screw head diameter,
Screw tightening in a narrow position can be performed very well.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, 1 is a bit,
A bit main body 2 integrally formed with an engaging portion 2a for engaging a cross drive hole of a screw at a front end thereof, and a sliding suction member 3 slidable near the front end of the bit main body 2 and capable of adsorbing a screw.
Is provided.

The sliding suction member 3 comprises a cylindrical magnetized member 4 loosely fitted in the vicinity of the engaging portion 2a of the bit body 2, and a substantially cylindrical protective member 5 containing the magnetized member 4. Have been. In this embodiment, a permanent magnet is used as an example of the magnetized member 4. The outer diameter of the protection member 5 is formed smaller than the diameter of the head of the corresponding screw. The protection member 5 includes a magnetized member having a diameter as large as possible, and has a small thickness in order to increase the magnetic force of the magnetized member 4. It is configured. The lower part of the protection member 5 covers the lower surface of the magnetized member 4 without interfering with the bit main body 2, and the lower surface of the protection member 5 is formed in a shape along the upper surface of the head of the screw.

The upper portion of the protection member 5 extends above the upper end of the magnetized member 4, and has a long hole 5a extending in the vertical direction at the diameter thereof, and the long hole 5a is formed in the long hole 5a. The pin material 6 penetrated perpendicularly to the axis of is fitted. The molding position of the elongated hole 5a is set so that the engaging portion 2a of the bit main body 2 projects a predetermined amount from the lower surface of the protection member 5 when the pin member 6 is located at an intermediate position of the longitudinal dimension. The protrusion amount of the engaging portion 2a from the lower surface of the protective member 5 at this time is set to an intermediate value between the maximum value and the minimum value of the gauge sinking depth q of the cross hole of the screw in the JIS standard. Is set to As shown in FIG. 3, the gauge sinking depth q of the cross hole is a dedicated measuring sleeve 20.
Measuring gauge 3 engaged with the drive hole of the screw from the reference surface s of
This shows the dimensions up to the zero end.

The bit 1 engages the engaging portion 2a with a driving hole of the screw, and makes the lower surface of the protection member 5 abut against the upper surface of the head of the screw to attract and hold the screw by the magnetic force of the magnetized member 4. And the protection member 5 and the magnetization member 4 are JI
The screw can be slid along the tolerance range of the gauge sink depth q of the cross hole of the screw according to the S standard and the bit main body 2. Now, assuming that the bit is positioned with the engaging portion 2a directed vertically downward and the protection member 5 is at the highest position, that is, the pin material 6 is in contact with the lower end of the long 6a,
When the drive hole of the screw is engaged with a, a gap is generated between the lower surface of the protection member 5 and the upper surface of the screw head.

Until the screw is engaged with the engaging portion 2a, the magnetic force of the magnetized member 4 acts only on the bit main body 2 to keep the protection member 5 at the raised position. By the engagement, the magnetic force of the magnetized member 4 also acts on the screw, and a mutual attractive force is generated between the magnetized member 4 and the screw,
The magnetized member 4 and the protection member 5 slidable along the bit main body 2 are attracted to the screw side, and the lower surface of the protection member 5 coincides with the upper surface of the screw head to properly hold the screw in the axial direction. 4 is securely held by the magnetic force. At this time, since the protective member 5 is thin overall, the magnetized member 4 is in a state very close to the screw, thereby strongly magnetizing the screw and increasing the mutual attraction force. This bit 1
In the above, by covering the magnetized member 4 loosely fitted on the outer periphery of the bit main body 2 with the protection member 5, the magnetized member 4 can be protected, for example, when the bit 1 is accidentally dropped from a workbench or the like. Since the protective member 5 has an outer diameter equal to or smaller than the diameter of the screw head, it is possible to perform a satisfactory screw tightening operation even on a screw hole provided at the back of a hole having a diameter slightly larger than the diameter of the screw head. It is possible.

When the bit main body 2 is formed of a non-magnetic material such as stainless steel, the operation range of the magnetizing member 4 and the protection member 5 can be widened and the operation can be performed smoothly. It is suitable for a screw with a large nominal diameter, which has a large allowable error range. In this case, it is difficult to keep the protection member 5 at the raised position, and when holding the screw with the engaging portion 2a directed vertically downward, the protection member 5 is once lowered after holding the screw at the tip. However, since the amount of movement of the protection member 5 and the magnetization member 4 is about the maximum error range of the gauge sinking depth q of the cross hole of the screw, the engagement portion 2a may not come off from the drive hole of the screw. In addition, when the screw is tightened, a certain amount of vertical pressing force is applied to the bit 1, so that the engaging portion 2 a of the bit main body 2 is securely moved to the depth of the screw driving hole by the pressing force. As a result, it is possible to perform the screw tightening operation while securely holding the screw.

When the bit body 2 is formed of a magnetic material, it is desirable that the material of the bit body 2 has a lower magnetic permeability than that of the screw material. That is, by setting the material forming the bit body 2 to have a lower magnetic permeability than the screw material, the magnetic force of the bit body 2 magnetized by the magnetized member 4 is smaller than the magnetic force of the screw magnetized when held. Become. Therefore, the sliding of the magnetized member 4 with respect to the bit main body 2 can be facilitated, whereby the above-described operation can be further clarified, and the moving range of the magnetized member 4 and the protection member 5 can be set larger. Is possible.

In this embodiment, the sliding and attracting portion 3 is formed by the magnetized member 4 and the protective member 5, but the present invention is not limited to this. It is also possible to implement by providing a suction hole and connecting an air suction device or the like to this suction hole,
Further, the present invention can also be implemented by providing a sleeve material which is slidable without falling off along the bit main body 2 and whose lower end surface is formed in a shape along the upper surface of the head of the screw, and magnetizes this sleeve material. is there.

[0015]

As described above, the bit of the present invention is:
Yes vital nonmagnetic an engaging portion for engaging the drive screw holes also
Is provided with a bit main body made of any material having a lower magnetic permeability than the engaging screw, and a magnetized member slidable along the bit main body near the engagement portion of the bit main body. provided with slidable and tip integrally encloses the magnetizing member
A protection member having a surface formed along the surface of the screw head facing the screw member is provided .
So that the tip of the engaging part of the main body always projects a predetermined amount
Of the magnetized member against the bit body
Can be extremely smooth, and the size of the screw drive hole
Even if an error occurs, make sure that the bit
At the same time, slide the protective member smoothly to
Contact along the surface of the screw head, and
Can be reliably held in a correct posture, and there is an advantage that a screw tightening operation can be performed without breaking a driving hole of the screw. Also, especially the bit body
If it is made of a material with low magnetic permeability,
Can be slid onto the bit body while it is slidable.
Engagement and protection at all times, regardless of the orientation of the bit axis
Can maintain the state where the tip of the part matches the screw
There are advantages. Further, the magnetized member is included in the protective member.
The magnetized member is located very close to the screw
And can hold the screw strongly,
The member is protected by a protective member, and the magnetized member is cracked or chipped.
There is also an advantage that damages such as can be prevented. one
On the other hand, the protection member is configured with an outer diameter less than the screw head diameter
Therefore, for example, with a bottomed hole slightly larger than the screw head diameter
Tighten to narrow places such as workpieces with screw holes on the bottom
Can be used for workpieces where
There are also other advantages.

[0016]

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG.

FIG. 2 is a front view showing a main part of a bit according to the present invention.

FIG. 3 is an explanatory diagram of a gauge sinking depth of a cross hole.

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 bit 2 bit body 2a engaging part 3 sliding attraction member 4 magnetizing member 5 protective member 5a elongated hole 6 pin material

Claims (2)

(57) [Claims] 1. A engaging portion for engaging the drive screw holes perforated vital
Use a non-magnetic material or a material with a lower magnetic permeability than the engaging screw.
The provided bit body portion comprising either, slidably and tip provided with a slidable magnetic member along the bit body portion in the vicinity of the engagement portion of the bit body portion, integrally encloses the magnetizing member A protective member is formed in a shape along the surface of the screw head facing the surface, and a distal end surface of the protective member is provided .
The tip of the engaging portion of the bit main body always projects a predetermined amount from
A bit characterized in that it is configured to 2. The bit according to claim 1, wherein the protection member has an outer diameter smaller than a screw head diameter .