JPS62848Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a screw tightening tool used for assembling or removing parts.A strong magnet is attached to the tool to attract the screw to the tip of the tool, increasing work efficiency. It is intended for this purpose.

Tightening tools such as screwdrivers used for tightening or removing screws can easily fit and tighten the screw when the tightening part is on the outer surface, but it is difficult to tighten in narrow or intricate places. This is very inconvenient when tightening the parts. For this reason, a magnetic screwdriver is used in which the tip of the screwdriver itself is magnetized, which is inserted into the groove of the screw head, attracts the screw, and transports the screw to the tightening location on the workpiece. However, with conventional magnetic screwdrivers, the magnetic force only acts on the grooves in the screw head, so the magnetic effect is extremely low. could not be adsorbed. Also,
When impact force or mechanical stress is applied to the magnet of the screwdriver, the magnetic force of the magnet decreases, and the screwdriver bit has to be magnetized repeatedly before tightening work that day.

Furthermore, in recent years, as part of efforts to save labor in assembly work through the mass production system, screw tightening devices have been used to automatically perform the work of sequentially attaching screws of the same type on the production line. The screw tightening tool of this type of screw tightening device is equipped with a means for sequentially supplying screws to the tip of a screwdriver bit, and a drive mechanism for rotationally driving the screwdriver bit. While holding the screw, move this screw toward the workpiece,
The drive mechanism is actuated at a predetermined position to tighten the screw to the workpiece. However, conventional screwdriver bits use a method of magnetizing the screwdriver bit itself to make it a permanent magnet as a means of holding the screw at the tip of the screwdriver bit, so it is necessary to strengthen the magnetic force beyond a predetermined limit. That is difficult. Therefore, there is an inconvenience in that the screw falls off from the tip of the driver bit before it is tightened, which often affects work efficiency.

This tool was devised with attention to these circumstances, and by placing a strong magnet around the outer periphery of the screwdriver bit and forming a magnetic path with the screwdriver bit, it is possible to tighten screws. To provide a screw tightening tool that prevents the screw from falling from the tip of a driver bit and can reliably tighten the screw at a predetermined location.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention. 1 is a driver, 2 is its shaft, 3
is the driver bit. A magnet holder 4 is fitted onto the shaft portion 2 and is composed of a non-magnetic material 6 and a magnetic material 7 covering the magnet 5. This magnetic holder is strongly attracted to the shaft of the driver by the strong magnetic force of the magnet. In this embodiment, three magnets are installed in the magnet holder 4, with one pole in contact with the shaft and the other pole on the outside in the radial direction, and all have the same magnetic pole, that is, the S pole in FIG. is in contact with the shaft. At this time, the driver bit 3 is magnetized by the magnetic field of the magnet 5, and the tip of the bit 3 becomes an S pole due to magnetic induction. Therefore, the magnetic line of force 10 emerging from the north pole of the magnet 5 passes through the tip of the driver bit 3, passes through the shaft portion 2, and returns to the south pole of the magnet 5, forming a magnetic circuit. That is, the driver bit 3 forms a magnetic path of the magnet 5. Now, when the screw 11 is brought close to the tip of the screwdriver bit 3, the screw, which is a magnetic substance, is magnetized by magnetic induction and is strongly attracted to the screwdriver bit 3.

FIG. 2 is a sectional view taken along the line taken along the line in FIG. 1 of the magnetic holder 4 of the above embodiment. Three magnets 5 are installed in the magnet holder 4, and are arranged so that they have the same magnetic pole toward the center. In the first embodiment, three strong permanent magnets are arranged in the magnet holder 4, so that the attractive force of the driver bit 3 can be strengthened. The non-magnetic material 6 fixes the magnet 5 and has the role of protecting the magnet 5 from receiving mechanical impact force, and is made of non-magnetic material such as constituent resin or brass.

FIG. 3 is a sectional view of a second embodiment of the magnetic holder, in which the entire magnetic holder is composed of a magnet 5 such as a permanent magnet. This increases the magnetic force by increasing the size of the magnet part, thereby reducing the weight of the magnetic holder itself.

Further, the magnet 5 is covered with non-magnetic materials 6 and 6' in the vertical direction including the shaft, and a cylindrical magnetic material 7 is fixed to the outer periphery of the magnet 5, and the lower end of the cylindrical magnetic material is connected to a driver. It extends in an inverted conical shape toward the tip of bit 3. As a result, a cavity is formed between the magnetic body 7 and the tip of the driver bit 3. Now, when the screw 11 is attracted to the screwdriver bit 3, the lines of magnetic force 10 coming out from the N pole of the magnet 5 pass through the air through the magnetic body 7, and pass through the screw 11, then the screwdriver bit 3, and the shaft part 2. A magnetic circuit reaching the S pole of the magnet 5 is formed. In this case, the magnetic body 7, the screw 11, the driver bit 3, and the shaft portion 2 all have high magnetic permeability, and since the permeation distance of air with low magnetic permeability is short, the attractive force of the driver bit is strong.

FIG. 4 is a sectional view of a second embodiment of the present invention.
The magnet holder 4 is made by covering the outer periphery of the shaft portion 2 with a cylindrical non-magnetic material 9 except for the driver bit 3, and a cylindrical rubber magnet 8 is attached to the outer periphery of the non-magnetic material. The upper part of the rubber magnet 8 is bonded in contact with the shaft part 2, and the lower part thereof protrudes downward from the non-magnetic material and extends almost to the vicinity of the driver bit 3. The rubber magnet 8 is attached so as to form a pair of magnetic poles at both ends in the axial direction of the driver 1.
In the illustrated embodiment, when the screw 11 is now attracted to the driver bit 3, the rubber magnet 8
emits magnetic lines of force from the N pole at the lower end, passes through the screw 11, passes through the driver bit 3 and the shaft portion 2, and forms a magnetic circuit that reaches the S pole at the upper end of the rubber magnet 8. In this embodiment, the lower end of the rubber magnet 8 can be brought close to the screw head.
The distance that the magnetic lines of force permeate through the air, which has low magnetic permeability, is short, so the screw attraction force of the screwdriver bit can be made stronger. Rubber magnets are soft, so they do not damage the workpiece, and
It is not demagnetized by mechanical stress.

Since the present invention has the above-described structure and operation, the lower end of the magnet or magnetic material can be brought close to the screw head. Therefore, the distance through which the magnetic lines of force permeate through the air, which has low magnetic permeability, is short, and the screw attracting force of the screwdriver bit can therefore be made stronger.

Furthermore, since a cavity is formed between the lower end of the magnet or magnetic material and the tip of the driver bit, even screw heads with large protruding shapes can be held without any problem.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the - line of the same embodiment, Fig. 3 is a cross-sectional view of the second embodiment of the present invention, and Fig. 4 is a cross-sectional view of the embodiment of the present invention. Third idea
FIG. 1: Driver, 2: Shaft, 4: Magnetic holder, 5: Magnet.

Claims (1)

[Scope of utility model registration request] A ring-shaped magnet holder is fitted onto the shaft of the driver bit, and a magnet such as a permanent magnet is attached to the magnet holder in contact with the shaft of the driver. The attached magnetic body is formed into a cylindrical shape surrounding the driver and extends toward the tip of the driver bit, and a cavity is formed between the magnet or the magnetic body and the tip of the driver bit. A screw tightening tool featuring: