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EP-4266941-B1 - MAGNETIC BUTTON

EP4266941B1EP 4266941 B1EP4266941 B1EP 4266941B1EP-4266941-B1

Inventors

  • BREZZI, SIMONE

Dates

Publication Date
20260506
Application Date
20211221

Claims (8)

  1. A magnetic button comprising a first button member (10, 10') incorporating an annular permanent magnet (12) and a second button member (50) incorporating a body (52) which is made of ferromagnetic material, the first button member and the second button member being magnetically couplable and uncouplable by moving them towards and away from each other, respectively, in a coupling direction, wherein the first button member (10, 10') comprises an axial alignment element (30, 42') between the second button member and the first button member, characterized in that , a central body (20) made of ferromagnetic material is arranged in a cavity (18) of the annular magnet (12) and it has a face (24) that is coplanar with a face (14) of the annular magnet which is directed, during use, towards the second button member and in that the axial alignment element (30, 42') being an edge (30, 42') which delineates a housing (44, 44') with a flared opening (31) for receiving the second button member (50), and wherein a diameter (D5) of said housing is smaller than an external diameter (D7) of the second button member (50).
  2. A magnetic button according to claim 1, wherein the central body of the first button member has a diameter (D3) which is approximately equal to an internal diameter (D2) of the cavity (18) of the annular magnet (12).
  3. A magnetic button according to claim 1 or 2, wherein the central body (20) has a projecting edge having a transverse dimension (D4), with respect to the coupling direction, greater than the internal diameter (D2) of the cavity of the annular magnet (12), the projecting edge (25) being in contact with a face (16) of the annular magnet opposite the face (14) of the annular magnet directed, during use, towards the second button member.
  4. A magnetic button according to any one of the preceding claims, wherein the second button member has a dimension (D6) transverse to the coupling direction between an external diameter (D1) and the internal diameter (D2) of the annular magnet.
  5. A button according to the preceding claim, wherein the edge is formed by a ring (30) of non-magnetic material.
  6. A magnetic button according to claim 6, wherein the edge comprises a shaped plate (42').
  7. A magnetic button according to any one of the preceding claims, wherein the first button member (10, 10') comprises a cover (32) which completely covers at least the central body (20) made of ferromagnetic material.
  8. A magnetic button according to any one of the preceding claims, wherein the second button member (50) comprises a cover (56) which completely covers at least the ferromagnetic body (52).

Description

Field of the invention The present invention relates to a magnetic button. The invention has been developed with particular regard to a button for the textile sector, leather goods or footwear, to be applied to fabrics or leathers or the like. Document JP S59 126606 discloses a magnetic button according to the preamble of claim 1. Technological background There have been known for some time magnetic buttons which are used both on items of clothing and particularly to close purses and bags. Typically, a magnetic button is formed by a pair of elements, of which one is provided with a disk-like magnet and the other is provided with a ferromagnetic portion. The magnetic properties of the metal cause the two elements placed close together to be attached to each other, closing the button. A problem with magnetic buttons is that, in order to ensure a satisfactory retention of the button, they they must be relatively large in diameter and/or thick. While in some applications, such as closing a bag, size is not necessarily an issue, in others it would be preferable to provide a small button. On the other hand, another problem of known magnetic buttons is that, if they are small, they exert a minimal magnetic field, which is insufficient to ensure acceptable retention of the button, in the presence of normal stresses. For example, if the button is used in an item of clothing, it is naturally necessary for the button to remain closed despite the inevitable stresses to which it is subjected as a result of the movements of the person wearing the garment. Therefore, it is evident that a small button with a small magnet which generates a minimal magnetic field and which therefore tends to become open accidentally, is not suitable. Some known devices have an annular magnet; a small protuberance on the face of one of the two elements is inserted in a corresponding recess in the face of the magnetic component, in the hole of the annular magnet. This is a solution for ensuring the correct axial alignment of the two elements and to prevent them from sliding transversally with respect to each other. In fact, the force necessary to detach a magnet from a ferromagnetic object by making them slide transversely relative to each other is substantially lower and therefore without the protuberance the risk of accidental release would increase. The protuberance and the recess have a diameter which is necessarily as small as possible because it corresponds to a diameter of the hole in the annular magnet: increasing the diameter of the hole corresponds to a reduction of the volume of the magnet and, therefore, of the intensity of the magnetic field thereof. In the region of the recess, sometimes oxide can form, which affects the aesthetic appearance thereof. Furthermore, a recess with a diameter which is necessarily reduced is subjected to clogging by oxide or impurities. In the event of even partial blockage, the two elements of the button may not perfectly adhere to each other, reducing the magnetic attraction force and, therefore, the seal of the button. US4941235 discloses a magnetic lock closure device with a first part and a second part. The first part includes an annular permanent magnet having a center bore, a first ferromagnetic member formed like a disk plate and attached to one polarity side of the permanent magnet and a nonmagnetic outer cover having a center bore and enclosing the permanent magnet and first ferromagnetic member. The second part includes a second ferromagnetic member adapted to be removably attached to the other polarity side of the permanent magnet. The first and second ferromagnetic members have respective ferromagnetic rods at the center extending therefrom. Statement of invention An object of the invention is to solve the problems of the prior art. Another object is to provide a button with reduced dimensions. Another object of the invention is to provide a magnetic button with optimum retention. Furthermore, it is desirable to provide a magnetic button that has no exposed portions subject to oxidation. Another object is to provide a device which is economical, simple, reliable during use and secure. According to a first aspect, there is described a magnetic button comprising a first button member and a second button member. The first and second button members can be stably anchored to a substrate. A substrate may be a sheet, for example, a fabric, leather, plastics sheet. The second button member and the first button member can be coupled and uncoupled magnetically by moving them towards and away from each other, respectively. The first button member comprises a magnet. The magnet is annular, with a cavity which is preferably circular. A central body of ferromagnetic material is inserted in the cavity of the annular magnet. The second button member comprises a ferromagnetic body. The Applicant has found that a button which is formed in this manner has a greater efficiency than a conventional magnetic but