TECHNICAL FIELD OF THE INVENTION

The present invention relates to a magnetic fastener for releasably fastening a first object to a second object. A single magnetic fastener may be used as a fastener button. A plurality of magnetic fasteners may be used as a so-called magnetic zipper.

PRIOR ART

US 2011/ 0 108 550 A1 and US 2014/ 0 143 985 A1 disclose magnetic fasteners for use as fastener buttons. Each of these magnetic fasteners comprises a pair of first and second fastening elements which are attracted to each other by a magnetic force. The magnetic force holds the two fastening elements in a fastened relative arrangement. The magnetic fasteners may be opened by separating the respective two fastening elements against the magnetic force.

US 2019/ 0 075 869 A1 discloses a magnetic zipper including two elongate units, each attached to edges of material, one elongate unit including a series of magnets positioned within a tube, the other elongate unit including a ferromagnetic material that is attracted by the magnetic field of the series of magnets in the other elongate unit. The magnetic attraction between the two elongate units brings the edges of material together and holds them together.

US 10 582 734 B1 discloses a magnetic zipper including a pair of mating strands each having a plurality of spaced teeth formed on an inner edge thereof with mating notches formed there between. Positioned within each of the notches on both strands is a magnet having a given polarity. Attached to each tooth on both strands is a magnet having a polarity opposite to the given polarity. The size of geometric configuration of the teeth and notches successively varies so that the two strands cannot be inadvertently joined when misaligned. To open the zipper, the tenuously-held zipper strands are pulled apart.

US 10 586 641 B2 discloses a magnetic zipper having two complementary magnetic closure elements, each of the two complementary magnetic closure elements including an elongated magnet carrier having a single direction of main extension, and a plurality of permanent magnet supported by the magnet carrier in defined positions along the direction of main extension. The permanent magnets following to each other in the direction of main extension are arranged in a closure alignment pattern having a magnetic non-repetition length extending over three or more of the permanent magnets. The elongated magnet carriers of the two complementary closure elements may comprise complementary surface contours fitting into each other orthogonally to their direction of main extension when the two complementary closure elements are both aligned in their directions of main extension and in rotation direction around their directions of main extension.

US 2018/ 0 042 321 A1 discloses a magnetic fastener assembly including a first clasp member, a second clasp member, a first magnet and a metallic component. The first clasp member defines a first cavity sized to receive a first portion of a zipper and defines a first portion extending over the first cavity. The second clasp member defines a second cavity sized to receive a second portion of the zipper and defines an overhang. The first magnet is secured to one of the first portion of the first clasp member and the overhang of the second clasp member. The metallic component is secured to another of the first portion of the first clasp member and the overhang of the second clasp member. The overhang is sized to receive the first portion of the first member to align the first magnet and the metallic component for magnetic interaction there between. The first and second clasp members can only be separated by pulling them apart normally to the parallel planes of main extension of the first magnet and the metallic component.

US 9392829 B2 discloses a device for magnetic clasping for closing accessory including at least one permanently magnetized assembly arranged at one end of one surface of the accessory, while a plurality of ferromagnetic elements and/or permanently magnetized assemblies are arranged longitudinally on the other surface of the opposite end thereof. The magnetized assemblies of one surface are suitable for attracting a magnetized assembly of the other surface. The magnetized assemblies and/or ferromagnetic elements of each surface are arranged such that, by placing the ends of the surfaces vertically adjacent to another, a plurality of adjustment positions of the surfaces are obtained relative to the positions of the magnetized assemblies and ferromagnetic elements. Each magnetized assembly of one surface engages with a magnetized assembly of a ferromagnetic element of the other surface in each one of the adjustment positions to close any magnetic field. The engaged surfaces may only be disengaged by linearly moving the magnetized assembly of one surface with respect to the magnetized assembly or ferromagnetic element of the other surface in a direction normal to the surfaces.

US 2 648 884 A discloses an interlocking magnetic clasp that is adapted for such uses as a connector for the ends of necklaces, bracelets and the like, a garment fastener or a belt fastener. The magnetic clasp comprises rigid separable sections having no movable parts. At least one of the separable sections is a permanent magnet. The separable sections are held in an interlocked relation by magnetic attraction. The separable sections are formed with faces which are complemental in shape. The face of each section is formed with two parallel, generally flat face portions inclined to the longitudinal axis of a body portion of the section. The face portions are extended longitudinally inwardly in overlapping relation with the intervening portion of the body undercut to provide a tongue and complementally shaped groove, which latter has a bottom wall and a side wall. In the assembled position of the sections, the tongue of each section is disposed in the groove of the other section, whereby the end faces of each tongue and the complementary groove serve as abutments to prevent separation of the sections in an axial outward direction. The interlocking tongues and grooves also prevent separation of the sections in response to forces tending to effect relative angular movement of the sections. The sections may only be separated in a single linear direction, disengaging the tongues and grooves.

OBJECT OF THE INVENTION

It is the object of the present invention to provide a magnetic fastener for releasably fastening a first object to a second object that is suitable for a magnetic zipper, that securely fastens the first object to the second object but which nevertheless easily releases the first object from the second object, and that is producible at comparatively expenditure.

SOLUTION

According to the present invention, the object of the invention is solved by the features of claim 1. Preferred embodiments of the invention are defined in the dependent claims.

DESCRIPTION OF THE INVENTION

The present invention relates to a magnetic fastener for releasably fastening a first object to a second object. The magnetic fastener comprises at least one pair of first and second fastening elements. The first fastening element comprises a first flat magnetic body having a first plane surface, and the second fastening element comprises a second flat magnetic body having a second plane surface. One of the first and second flat magnetic bodies is permanent magnetic, and the other of the first and second flat magnetic bodies is either permanent magnetic or ferromagnetic. The first fastening element comprises a first frame attached or configured to be attached to the first object and holding the first flat magnetic body. The second fastening element comprises a second frame attached or configured to be attached to the second object and holding the second flat magnetic body. In a fastened relative arrangement of the first and second fastening elements, the first and second plane surfaces are parallel, face each other and overlap by more than 50 %, when viewed in a direction normal to the first and second plane surfaces. Further in the fastened relative arrangement of the first and second fastening elements, the first and second flat magnetic bodies magnetically attract each other, and, in a locking direction parallel to the first and second plane surfaces, a first locking surface of the first fastening element is supported at a second locking surface of the second fastening element, the first and second locking surfaces being parallel and extending transversely to the locking direction. Even further in the fastened relative arrangement of the first and second fastening elements, in an un-locking direction opposite to the locking direction, no locking surface of the first fastening element is supported at any locking surface of the second fastening element.

The feature that the first and second plane surfaces are parallel, does not exclude that the first and second plane surfaces enclose a small angle of typically less than 10°, preferably of less than 5 ° and more preferably of less than 3°. Most preferably, the first and second plane surfaces are as exactly parallel as possible with usual tolerances of mass-produced articles. Essentially the same applies to all other features of the present invention according to which any other surfaces are parallel. However, locking surfaces supported at each other should always be as exactly parallel as possible with usual tolerances of mass-produced articles. Each of the first and second fastening elements comprises a flat magnetic body and a frame for holding the flat magnetic body. Further, the frames of the fastening elements are involved in providing at least one of the first and second locking surfaces, as the first and second locking surfaces may not both be provided by the flat magnetic bodies. In other words, the magnetic bodies of the fastening elements primarily serve for providing a magnetic attracting force between the fastening elements, whereas essential mechanical functionality of the first and second fastening elements is provided by their frames.

The magnetic attracting force between their magnetic bodies holds the first and second fastening elements in their fastened relative arrangement. However, forces between the first and second fastening elements exerted in the locking direction are at least partially supported by the first locking surface of the first fastening element supported at the second locking surface of the second fastening element. This is a mechanical rather than a magnetic support. The locking direction extends parallel to the plane surfaces of the flat magnetic bodies, the first and second locking surfaces being parallel and extending transversely to the locking direction. In the unlocking direction opposite to the locking direction, no locking surface of the first fastening element is supported at any locking surface of the second fastening element, i. e. no supported locking surfaces are provided, so that the first and second fastening elements may be moved out of their fastened relative arrangement by a relative movement in the un-locking direction. It is not necessary to move the first and second fastening elements normal to the plane surfaces of the magnetic bodies to get them out of their fastened relative arrangement. Additionally, it is also possible to bring the first and second fastening elements in their fastened relative arrangement by a relative movement along the plane surfaces of the magnetic bodies; there is no need for a relative movement exactly orthogonal to the plane surfaces of the magnetic bodies. Thus, despite the fact that mechanical forces in the locking direction are mechanically supported, the fastening elements may easily be brought in their fastened relative arrangement and also out of their fastened relative arrangement, whenever desired.

At least parts of the first and second locking surfaces may be inclined towards the first and second plane surfaces such that angles between the part of the first locking surface and the first plane surface and between the part of the second locking surface and the second plane surface are smaller than 85°, preferably smaller than 75°. In other words, the complementary first and second plane surfaces may be undercut or hook-shaped such that a force between the fastening parts in the locking direction forces the fastening elements in a positive fit of their first and second locking surfaces. Nevertheless, the fastening elements are still easily separated by a relative movement in the un-locking direction. The angles between the inclined parts in the plane surfaces may even be smaller than 60°, and they may go down to not more than 45°. Generally, the inclination of the first and the second locking surfaces may also be realized by steps such that parts of the first and second plane surfaces are orthogonal and other parts of the first and second plane surfaces are parallel to the first and second plane surfaces. However, such a stepped design of the first and second locking surfaces is not preferred over a design in which the inclination angles between the locking surfaces and the plane surfaces of the magnetic bodies is between 45° and 75°.

The first and second frames of the first and second fastening elements are preferably made of plastic. Alternatively, they may be made of other non-permanent magnetic and non-ferromagnetic material. Particularly, the first and second frames may be made by injection molding starting material into a mold or by deep drawing a sheet of starting material. The step of deep drawing may be implemented by applying a pressure difference across the sheet of starting material.

If the first and second plane surfaces of the first and second flat magnetic bodies do not overlap by more than 95 %, preferably by not more than 90 % and even more preferably by not more than 80 %, when viewed in a direction normal to the first and second plane surfaces, such that the first plane surface has a back part not overlapping with the second plane surface, and the second plane surface has a front part not overlapping with the first plane surface being viewed in the locking direction, the effective magnetic force has a component parallel to the first and second plane surfaces in the locking direction in addition to the component normal to the plane surfaces of the magnetic bodies. This component of the magnetic force in the locking direction pulls the first and second fastening elements into their fastened relative arrangement and holds the first and second fastening elements in their fastened relative arrangement even without any friction counteracting relative movement of the first and second fastening elements in the un-locking direction.

Even an airgap may be provided between the first plane surface and the second plane surface in the fastened relative arrangement of the first and second fastening elements in order to avoid any direct contact and particularly any impact between the magnetic bodies. Many permanent magnetic materials are quite brittle and sensitive to impact loads. A direct contact between the first and second magnetic bodies and a high friction due to such a direct contact may also be avoided by means of at least one of a first cover layer of the first frame covering the first plane surface of the first magnetic body and a second cover layer of the second frame covering the second plane surface of the second magnetic body.

When viewed in the un-locking direction, the first and second locking surfaces may at least partially overlap with the first flat magnetic body. In a practical embodiment, the first locking surface of the first fastening element may be provided by the first flat magnetic body, i.e. by a part of the circumference of the first flat magnetic body, or by a part of the first frame covering this circumference. By means of the overlap of the first and second locking surfaces with the first flat magnetic body, a flat overall design of the magnetic fastener with regard to its height between backsides of its first and second frames is achieved.

In the locking direction, the first and the second locking surfaces are preferably provided at front ends of the first and second fastening elements. An additional third locking surface at a back end of the first fastening element may be supported at a fourth locking surface at a back end of the second fastening element. These third and fourth locking surfaces may also be parallel and extending transversely to the locking direction. Additionally, the third and fourth locking surfaces may at least partially overlap with the second flat magnetic body when viewed in the locking direction. The third and fourth locking surface provide for an additional mechanical support of the first fastening element at the second fastening element at their back ends in addition to the mechanical support provided by the first and second locking surfaces at the front ends of the first and second fastening elements.

The first fastening element may have a first un-locking guidance surface and the second fastening element may have a second un-locking guidance surface. The first and second un-locking guidance surfaces may be configured for separating the first and second plane surfaces of the first and second flat magnetic bodies in the direction normal to the first and second plane surfaces, when the first un-locking guidance surface slides over the second un-locking guidance surface in the un-locking direction. The inclination of the first and second un-locking guidance surfaces with respect to the first and second plane surfaces determines how quickly the first and second plane surfaces are separated when the first and second fastening elements are moved relative to one another in the un-locking direction. A small inclination results in a slow separation only requiring a small force in the un-locking direction. A high inclination results in a fast separation requiring a higher force in the un-locking direction. When viewed in the locking direction, the first and second locking surfaces may be provided at front ends of first and second fastening element, whereas the first and second un-locking guidance surfaces may be provided at back ends of the first and second fastening elements. Generally, the first and second un-locking guidance surfaces may be provided somewhere between the front ends and the back ends of the first and second fastening elements, or they may even extend from the front ends to the back ends of the first and second fastening elements.

In a preferred embodiment of the magnetic fastener, the first and second frames or even the first and second fastening element, except of magnetic polarization directions of their magnetic bodies, are identical. Particularly, same permanent magnetic bodies may be arranged in opposite orientations within same first and second magnetic frames to provide the first and second fastening elements.

A magnetization direction of any one of the first and second flat magnetic bodies being permanent magnetic may be normal to the first and second plane surfaces or parallel to the locking or unlocking direction. Generally, flat permanent magnetic bodies with magnetization directions normal to their plane surfaces are cheaper than flat permanent magnetic bodies with magnetization directions parallel to their plane surfaces. In a practical embodiment, the first and second magnetic bodies are disc-shaped. Disc-shaped permanent flat magnetic bodies with magnetization directions normal to their plane surfaces are available at low cost.

The first frame may have a first plane attachment surface, and the second frame may have a second plane attachment surface. The first and second attachment surfaces may be parallel, and they may also be parallel with respect to the first and second plane surfaces of the first and second flat magnetic bodies.

In a particular embodiment of the magnetic fastener, the first attachment surface is inclined with respect to the first plane surface such that a virtual continuation of the first plane surface and the first plane attachment surface or a virtual continuation thereof, when viewed in the locking direction, intersect behind the first plane surface at a backward inclination angle. The backward inclination angle may be at least 2° or at least 4°, and it is, as a rule, not more than 45° or not more than 30°. With these backward inclination angles the locking surfaces are still active in an external force direction along the first attachment surface. If the first and second attachment surfaces are parallel in this particular embodiment of the magnetic fastener, the second attachment surface is inclined with respect to the second plane surface such that a virtual continuation of the second plane surface and the second plane attachment surface or a virtual continuation thereof, when viewed in the un-locking direction, intersect behind the second plane surface at the backward inclination angle.

In an alternative particular embodiment of the magnetic fastener, the first attachment surface is inclined with respect to the first plane surface such that a virtual continuation of the first plane surface and the first plane attachment surface or a virtual continuation of the first plane attachment surface, when viewed in the locking direction, intersect in front of the first plane surface at a forward inclination angle. The forward inclination angle may be at least 2° or at least 4°, and it is, as a rule, not more than 90° or not more than 45°. If the first and second attachment surfaces are parallel, the second attachment surface is inclined with respect to the second plane surface such that a virtual continuation of the second plane surface and the second plane attachment surface or a virtual continuation thereof, when viewed in the un-locking direction, intersect in front of the second plane surface at the forward inclination angle.

By means of the size of the backward or forward inclination angle, respectively, the functionality of the magnetic fastener may be varied to a large extent.

In the first particular embodiment, a relative movement of the first and second fastening elements in the locking direction moves the first and second plane attachment surfaces, and any objects attached thereto, together. In the alternative particular embodiment, the movement in the locking direction as such moves the first and second plane attachment surfaces away from each other. This may require a hooking-in movement of the one fastening element with respect to the other fastening element for bringing them into their fastened relative arrangement.

If a plurality of the pairs of first and second fastening elements, in the fastened relative arrangement of their first and second fastening elements, are aligned with parallel locking directions, a magnetic zipper is provided.

In such a magnetic zipper, the first and second frames of the pairs of the plurality of pairs of first and second fastening elements may all be identical. Alternatively, the first and second frames of the pairs of the plurality of pairs of first and second fastening elements may be shaped differently such that only selected first and second frames may get into the fastened relative arrangement. In this way, it may be ensured that the magnetic zipper only closes if its two sides are correctly aligned in longitudinal direction.

Additionally or alternatively, the permanent magnetic bodies of the pairs of the plurality of pairs of first and second fastening elements may all have the same or different magnetic polarization directions with respect to a direction of main extension of the magnetic zipper to ensure that only the associated first and second fastening elements get into their fastened relative arrangements by magnetic coding. For example, there may be permanent magnetic bodies of opposite and/or orthogonal magnetic polarization directions along one side of the magnetic zipper. Further, the permanent magnetic bodies of the pairs of the plurality of pairs of the first and second fastening elements may all have the same magnetic strength or they may have different magnetic strengths. For example, the magnetic strengths of the permanent magnetic bodies of the first and second fastening elements at the ends or at selected points along the length of the magnetic zipper may be higher than those of the permanent magnetic bodies of the first and second fastening elements in the intermediate areas of the magnetic zipper. This may ensure that the magnetic zipper is not involuntarily opened, on the one hand, and that it can nevertheless be voluntarily opened in selected intermediate areas, on the other hand.

The first frames and the second frames of the plurality of the pairs of the first and second fastening elements may individually be attached to the first and second objects fastened by means of the magnetic zipper. For example, the first and second frames may be glued or plastic-welded to the first and second objects. In another embodiment, the first frames and the second frames of the plurality of the pairs of the first and second fastening elements are attached to first and second flexible carrier tapes. In a particular embodiment, the first and second frames are injection molded to the first and second flexible carrier tapes. In another particular embodiment, the first and second flexible carrier tapes have mechanical zipper backs. Thus, the first and second flexible carrier tapes may each be attached to one side of a mechanical zipper via its mechanical zipper back to provide the mechanical zipper with the functionality of the magnetic zipper according to the present invention. In a further embodiment, the first frames and the second frames of the plurality of the pairs of first and second fastening elements are parts of first and second one-part shaped bodies made of plastic. These first and second one-part shaped bodies made of plastic may be flexible. In a practical embodiment, they may be made by deep drawing a sheet of starting material applying a pressure difference across the sheet of starting material. Advantageous developments of the invention result from the claims, the description and the drawings.

The advantages of features and of combinations of a plurality of features mentioned at the beginning of the description only serve as examples and may be used alternatively or cumulatively without the necessity of embodiments according to the invention having to obtain these advantages.

The following applies with respect to the disclosure - not the scope of protection - of the original application and the patent: Further features may be taken from the drawings, in particular from the illustrated designs and the dimensions of a plurality of components with respect to one another as well as from their relative arrangement and their operative connection. The combination of features of different embodiments of the invention or of features of different claims independent of the chosen references of the claims is also possible, and it is motivated herewith. This also relates to features which are illustrated in separate drawings, or which are mentioned when describing them. These features may also be combined with features of different claims. Furthermore, it is possible that further embodiments of the invention do not have the features mentioned in the claims which, however, does not apply to the independent claims of the granted patent.

The number of the features mentioned in the claims and in the description is to be understood to cover this exact number and a greater number than the mentioned number without having to explicitly use the adverb "at least". For example, if an element is mentioned, this is to be understood such that there is exactly one element or there are two elements or more elements. Additional features may be added to these features, or these features may be the only features of the respective product.

The reference signs contained in the claims are not limiting the extent of the matter protected by the claims. Their sole function is to make the claims easier to understand. BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is further explained and described with respect to preferred exemplary embodiments illustrated in the drawings.

Fig. 1 is a cross-sectional view along a locking direction of a pair of first and second fastening elements of a magnetic fastener in a fastened relative arrangement.

Fig. 2 is a cross-sectional view along the locking direction of frames of the first and second fastening elements of Fig. 1.

Fig. 3 is a perspective view of the frame of one of the first and second fastening elements of Fig. 2.

Fig. 4 is a back view of a magnetic fastener or zipper comprising a plurality of pairs of first and second fastening elements which are in their fastened relative arrangements.

Fig. 5 is a cross-sectional view of another embodiment of the magnetic fastener showing the first and second fastening elements in their fastened relative arrangement.

Fig. 6 is a perspective view of an embodiment of the magnetic fastener comprising a plurality of pairs of first a second fastening elements whose frames are parts of first and second one-part shaped bodies made of plastic and which are shown in an un-fastened relative arrangement.

Fig. 7 shows a variant of the pair of first and second fastening elements according to Fig. 1 in which attachment surfaces of the fastening elements are inclined with respect to a locking direction in a first inclination direction, and

Fig. 8 shows a variant of the first and second fastening elements according to Fig. 1 whose attachment surfaces are inclined with respect to the locking direction in a second inclination direction opposite to the first inclination direction of Fig. 7. DESCRIPTION OF THE DRAWINGS

The magnetic fastener 1 depicted in Fig. 1 comprises a pair of a first fastening element 2 and a second fastening element 3. The first fastening element 2 comprises a first frame 4 and a first flat magnetic body 5. The second fastening element 3 comprises a second frame 6 and a second flat magnetic body 7. The first and second frames 4, 6 are identical. In Fig. 2 they are shown separately, i. e. without the magnetic bodies 6 and 7, and one of these frames 4, 6 is separately depicted in Fig. 3 in a perspective view. Each of the frames 4, 6 has an attachment surface 8 or 9, respectively, on its one side and an open cavity 10 or 11 , respectively, for receiving the respective flat magnetic body 5 or 7, respectively, on its other side. The first and second magnetic bodies 5 and 7 are disc-shaped, and the first and second cavities 10 and 11 are adapted to this disc-shape. The flat magnetic bodies 5 and 7 may be glued into the cavities 10 and 11. The flat magnetic bodies 5 and 7 magnetically attract each other in the fastened relative arrangement of the first and second fastening elements 2 and 3 depicted in Fig. 1. For this purpose, one of the first and second flat magnetic bodies 5 and 7 is permanent magnetic. The other one of the first and second flat magnetic bodies 5 and 7 is either also permanent magnetic, but of opposite polarization direction, or ferromagnetic. The frames 4 and 6 are neither permanent magnetic nor ferromagnetic. Preferably, they are made of plastic. In the fastened relative arrangement of the first and second fastening elements 2 and 3 according to Fig. 1 , an airgap 12 remains between the first and second flat magnetic bodies 5 and 7 to avoid a direct contact and particularly a direct impact of the first and second flat magnetic bodies 5 and 7.

Via a first locking surface 13 provided at the circumference of its flat magnetic body 5, the first fastening element 2 is supported at a second locking surface 14 provided by the frame 6 of the second fastening element 3 in a locking direction 15 parallel to a first plane surface 16 of the first flat magnetic body 15 and a second plane surface 17 of the second flat magnetic body 7. The first and second locking surfaces 13 and 14 extend transversely to the locking direction 15 and normal to the first and second plane surfaces 16 and 17. In the locking direction 15, the first and second locking surfaces 13 and 14 are provided at front ends of the first and second fastening elements 2 and 3. An additional third locking surface 18 provided by the frame 4 of the first fastening element 2 is supported at an additional fourth locking surface 19 provided at the second flat magnetic body 7 of the second fastening element 3 at the back ends of the first and second fastening elements 2 and 3. By means of the magnetic attraction between the flat magnetic bodies 5 and 7 the first and second fastening elements 2 and 3 are brought into and held in their fastened relative arrangement according to Fig. 1. However, forces between the first and second fastening elements 2 and 3 in the locking direction 15 are supported via the pairs of first and second locking surfaces 13 and 14 and third and fourth locking surfaces 18 and 19. In an un-locking direction 20 opposite to the locking direction 15, no locking surface of the first fastening element 2 is supported at any locking surface of the second fastening element 3, i.e. no supported locking surfaces are provided, so that the first and second fastening elements 2 and 3 may be separated from each other not only in a direction normal to their plane surfaces 16 and 17 but also in the un-locking direction 20.

Typically, a diameter of the first and second flat magnetic bodies 5 and 7 is in a range from some millimeters to very few centimeters, and a thickness of the first and second flat magnetic bodies 5 and 7 is in a range from few to some millimeters. The first and second frames will be somewhat larger and thicker.

Fig. 4 shows a magnetic fastener 1 comprising a plurality of pairs of first and second fastening elements 2 and 3 which are all aligned with respect to their un-locking directions 15. Fig. 3 shows the fastening elements 2 and 3 when viewing in this locking direction 15, i.e. on the back ends of the first and second fastening elements 2 and 3. With their attachment surfaces 8 and 9, the first and second frames 4 and 6 of the first and second fastening elements 2 and 3 are individually attached to first and second objects 21 and 22 which are fastened to one another by means of the magnetic fastener 1. The magnetic fastener 1 according to Fig. 3 comprising a plurality of aligned pairs of first and second fastening elements 2 and 3 may also be called a magnetic zipper.

Fig. 5 shows another embodiment of the magnetic fastener 1 comprising first and second fastening elements 2 and 3. However, the first and second fastening elements 2 and 3 have different frames 4 and 6, here. The frame 4 of the first fastening element 2 has the cavity 10 for receiving the first flat magnetic body 5 on its backside within its attachment surface 8. Thus, the frame 4 covers the plane surface 16 of the first magnetic body 5. The second frame 6 has the cavity 11 on its front side. In the fastened relative arrangement according to Fig. 4, the first fastening element 2 is supported via the first locking surface 13 provided by its frame 4 covering its flat magnetic body 5 at the second locking surface 14 provided by the frame 6 of the second fastening element 3. The first and second locking surfaces 13 and 14 are hook-shaped, and, with respect to the locking direction 15, they are provided at the front ends of the first and second fastening elements 2 and 3. However, there are no additional locking surfaces at the back ends of the first and second fastening elements 2 and 3. Instead, first and second un-locking guidance surfaces 23 and 24 of the first and second fastening elements 2 and 3 are provided here by the first and second frames 4 and 6. The un-locking guidance surfaces 23 and 24 are inclined with regard to the plane surfaces 16 and 17, and they separate the first and second plane surfaces 16 and 17 when moving the first fastening element 2 with respect to the second fastening element 3 in the un-locking direction 20. In the embodiment according to Fig. 4, the first and second plane surfaces 16 and 17 of the first and second flat magnetic bodies 5 and 7 are always slightly separated by the second frame 4 to avoid a direct contact or impact. Further, even in the fastened relative arrangement shown, the first and second plane surfaces 16 and 17 only partially overlap. This results in a higher component of the magnetic force between the first and second flat magnetic bodies 5 and 7 in the locking direction 15. The frames 4 and 6 may both be made by deep drawing a sheet of starting material using a pressure difference.

Fig. 6 shows a magnetic fastener 1 with a plurality of first and second fastening elements 2, 3 according to Fig. 5 whose first and second frames 4, 6 are integrally formed by first and second one-part shaped bodies 25 and 26 in a perspective view in an un-fastened relative arrangement. Both one-part shaped bodies 25 and 26 may be made by blistering sheets or foils of plastic for forming the first and second cavities 10, 11 in which the first and second flat magnetic bodies 5 and 7 are arranged.

Fig. 7, in a similar cross-sectional view as Fig. 1 , shows a variant of the magnetic fastener 1 according to Fig. 1 in which the first and second attachment surfaces 8, 9 are inclined with respect to the first and second plane surfaces 16, 17. The inclination is such that a virtual continuation of the first plane surface 16 and a virtual continuation of the attachment surface 8, when viewed in the locking direction 15, intersect behind the first plane surface 16 somewhere outside the drawing sheet at a backward inclination angle 27 of about 4° here. This backward inclination angle 27 results in that the attachment surfaces 8 and 9 get closer together when being moved in the locking direction 15, and it eases unfastening the magnetic fastener 1.

Fig. 8, in a similar cross-sectional view as Fig. 1 , shows a variant of the magnetic fastener 1 according to Fig. 1 in which the attachment surfaces 8 and 9 are inclined with respect to the plane surfaces 16 and 17 in an opposite direction as compared to Fig. 7. Here, the first attachment surface 8 and the first plane surface 16, when viewed in the locking direction 15, intersect in front of the first plane surface 16 somewhere outside the drawing sheet at a forward inclination angle 28. The forward inclination angle 28 is 4° here. The forward inclination angle 28 results in that the first and second fastening elements 2, 3 have to be unhooked to transfer them into their unfastened relative arrangement or hooked-in to bring them into their fastened relative arrangement.

LIST OF REFERENCE NUMERALS magnetic fastener first fastening element second fastening element first frame first flat magnetic body second frame second flat magnetic body first attachment surface second attachment surface first cavity second cavity airgap first locking surface second locking surface locking direction first plane surface second plane surface third locking surface fourth locking surface un-locking direction first object second object first un-locking guidance surface second un-locking guidance surface first one-part shaped body second one-part shaped body backward inclination angle forward inclination angle