JPS643372Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a suction tool using a permanent magnet.

At present, various types of suction tools using permanent magnets are in practical use, but most of them have one pole surface of the permanent magnet attracted to the object to be attracted, and the other pole surface in contact with the object. A round-shaped auxiliary iron piece is fixed in contact with the permanent magnet, and a closed magnetic path with low magnetic resistance consisting of the object to be attracted and the auxiliary iron piece is formed between the two poles of the permanent magnet, thereby increasing the attraction force.

Further, FIG. 1 shows a permanent magnet hook used for bags or clothes, which consists of a combination of a female tool (adsorption tool) a and a male tool (an object to be attracted) b. Its structure will be briefly explained.

1 is an annular permanent magnet magnetized in the thickness direction and has a gap hole 1a; 3 is a disc-shaped ferromagnetic plate that is in contact with the S pole surface of this magnet 1; a homogeneous projection 3a is provided in the center of the plate; It is provided and fitted into the gap hole 1a of the magnet 1. Reference numeral 2 denotes a cover made of a non-magnetic material, such as a thin brass plate, which also serves as a decoration and integrally covers the magnet 1 and the plate 3. Moreover, the male tool b has a projection 4a of the same quality provided in the center of a disc-shaped ferromagnetic plate 4. This protrusion 4a is connected to the gap hole 1a of the magnet 1.
If male tool b and female tool a are attracted to each other so that they fit into each other, the ferromagnetic plate 3, its protrusion 3a, the protrusion 4a of male tool b, and the ferromagnetic plate 4 will pass between the NS poles of magnet 1. A closed magnetic path with low magnetic resistance is formed, providing strong adsorption force. Note that even if one of the two protrusions 3a and 4a is omitted and the height of the other is extended to the depth of the gap hole 1a, a similarly strong adsorption force can be obtained.

Incidentally, in recent years, with advances in unmanned bank counters and unmanned railway ticket gate operations, cashless cards or paper slips with various information magnetically printed on them have begun to be used. When such magnetically printed cards or tickets are exposed to an external magnetic field, the magnetically recorded information is easily destroyed. For this reason, if a suction device using a permanent magnet as described above is used for a drawer drawer or a stopper for a handbag, the recorded information will be destroyed if such cards or paper towels are brought carelessly close to the suction device. There is a risk that That is, in the attracting tool shown in FIG. 1, when the magnet 1 is attracted, the two poles of the magnet 1 are short-circuited by the object to be attracted, and almost no leakage magnetic field is generated.
When the attracting surface of the magnet is opened, a wide leakage magnetic field y is generated as shown in the figure.

The purpose of this invention is to reduce the leakage magnetic field of such an adsorption device using a permanent magnet as much as possible, and to prevent the above-mentioned accidental destruction of magnetically recorded information.

FIG. 2 shows a female hook a of this invention which reduces the leakage magnetic field of the hook shown in FIG. 1, and the same numbers as those in FIG. 1 indicate the same thing. Note that the male hook b is the same as that shown in FIG. 1, and will therefore be omitted. In this embodiment, the attraction surface (N
An annular ferromagnetic plate 5 having substantially the same shape as the pole surface is brought into contact with the pole surface, and the two poles are paired with each other by a brass cover 2. As a result, as shown in the figure, a leakage magnetic field y occurs between the tip of the protrusion 3a of the ferromagnetic plate 3, which has relatively low magnetic resistance, and the hole edge 5a of the annular ferromagnetic plate 5 when not attracted.
is concentrated, and the leakage magnetic field existing on the attracting surface of the magnet 1 is almost eliminated. Furthermore, when attracting with the male tool b, a magnetic path with lower magnetic resistance is formed through the male tool b, so the attraction force is not significantly reduced by the ferromagnetic plate 5.

Note that these protrusions 3a and 4a are specially designed to be inserted into the hole 1a with a required gap, and this gap allows the magnetic closed circuit to be concentrated only on these protrusions 3a and 4a. .

In particular, in the present invention, the outer peripheral edge 5 of the ferromagnetic plate 5
If the hole edge 5a is extended and bent downward to shorten the gap between the hole edge 5a and the ferromagnetic plate 3, the magnetic flux will be concentrated in the gap, further reducing the leakage magnetic field.

An example of a means for specifically attaching the suction tool to a handbag or the like will be explained with reference to FIGS. 3 and 4. . . . 6a is attached to the ferromagnetic plate 3 constituting the other female member a, and a mounting plate 6 having similar leg pieces 6a to 6a is caulked 7. Washer 8
In the case where the cover 2 is used to secure the cover 2, other suitable means are planned.

Although this invention has been described above with reference to embodiments, this invention can be applied to adsorption tools using permanent magnets other than the embodiments.

It should be noted that the iron plate used in the examples may be replaced with other ferromagnetic materials such as nickel. Further, although it is desirable that the ferromagnetic plate 5 covers the entire attracting surface of the magnet 1, leakage magnetic fields can be sufficiently reduced even if the ferromagnetic plate 5 covers only the main part of the attracting surface.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional hook, FIG. 2 is a sectional view of an embodiment of the present invention, and FIGS. 3 and 4 are sectional views of an embodiment provided with attachment means. 1...Permanent magnet, 2...Cover, 3-5...Ferromagnetic plate, 6...Mounting plate, 7...Crimping, 8...Washer.

Claims (1)

[Scope of utility model registration request] A ferromagnetic plate is fixed to one of the magnetic pole faces of the permanent magnet 1 with a cover 2 made of a non-magnetic plate in a permanent magnet 1 having an appropriate gap hole 1a extending from one magnetic pole face to the other magnetic pole face. 3 or a protrusion 3a provided on the plate 3, and a ferromagnetic plate 4 which is removably magnetically attached to the other magnetic pole surface and has a protrusion 4a at the center facing the permanent magnet 1, to the permanent magnet 1. A permanent magnet is detachably magnetically attached to the ferromagnetic plate 4 in a configuration in which the permanent magnet is detachably magnetically attached to the ferromagnetic plate 4 through the gap hole 1a and without contacting the inner circumferential wall surface of the hole 1a. A suction device characterized in that an annular ferromagnetic plate 5 formed by holding the cover 2 and bending the inner and outer peripheries or the outer periphery toward the other magnetic pole surface is fixedly attached to the magnetic pole surface of the magnetic plate 1.