Magnetic attachment device for an object
The magnetic fixing device with a movable magnet system addresses the challenge of moving large or heavy objects by adjusting adhesion force, facilitating easy repositioning and reducing detachment effort.
Patent Information
- Application Number
- FR2022013561
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2022-12-16
- Publication Date
- 2025-01-17
- Estimated Expiration
- 2032-12-16
AI Technical Summary
Existing magnetic fixing devices for large and heavy objects require high adhesion forces to prevent separation, making it tedious and complex to move these objects relative to each other.
A magnetic fixing device with a movable magnet system that adjusts the magnetic adhesion force between two positions, allowing easy movement by altering the distance between the magnet and the magnetic surface, maintaining adhesion while reducing the force needed for separation.
Enables easy repositioning and movement of large or heavy objects without complete separation, reducing the effort required to detach and reattach them.
Smart Images
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Abstract
Description
Title of the invention: Device for magnetic attachment to an object
[0001] The present invention relates to a magnetic fixing device allowing the fixing device to be fixed to a surface of an object.
[0002] The invention also relates to a fixing system comprising such a fixing device.
[0003] Such a fixing device is for example intended to fix a tool, such as a robotic arm, on a surface of an object, such as a metal plate, on which the tool is to act. According to a particular application, the fixing device cooperates with the support of a robotic arm to fix the robotic arm on the hull of a naval vessel.
[0004] Magnetic fixing devices are known and make it possible to reversibly fix an object carrying the fixing device to an object having magnetic properties. Such a fixing device comprises one or more magnets and is dimensioned so that the objects remain attached to each other in the absence of external stress. For objects of large dimensions and / or significant mass, the magnetic adhesive force must be particularly great in order to prevent one of the objects from involuntarily separating from the other. To undo the fixing, it is then necessary to exert a force overcoming the magnetic adhesive force exerted by the fixing device on one of the objects and to separate the objects from each other or to have a controllable magnet making it possible to cancel the magnetic flux.
[0005] However, when it is simply desired to move the object carrying the fixing device relative to the other object, for example to reposition a tool in a new intervention zone, it is necessary to undo the fixing between the objects, move them apart, reposition the objects relative to each other and bring them closer together to fix them to each other in the new position. The moving operation is then tedious and can be particularly complex for objects of large dimensions and / or significant mass.
[0006] One of the aims of the invention is to overcome these drawbacks by proposing a magnetic fixing device ensuring robust fixing between two objects while allowing easy movement of one of the objects relative to the other.
[0007] To this end, the invention relates to a magnetic fixing device, comprising a magnetic fixing surface, intended to be applied to a magnetic surface of an object to be fixed to said object, and at least one magnet, the magnetic fixing surface extending at a variable distance from said magnet between a first position, in which the magnet is brought closer to the magnetic fixing surface to generate a first magnetic adhesion force immobilizing the magnetic fixing surface relative to the magnetic surface of the object, and a second position, in which the magnet is moved away from the magnetic attachment surface to generate a second magnetic adhesion force, less than the first magnetic adhesion force, said second magnetic adhesion force maintaining adhesion between the magnetic attachment surface and the magnetic surface of the object while allowing movement of the magnetic attachment surface on the magnetic surface of the object.
[0008] The magnetic fixing device therefore makes it possible to move the fixing device, and therefore the object carrying this device, relative to the object on the surface of which the fixing device is fixed without however canceling the magnetic flux maintaining the fixing device on the surface of the object. It is thus possible to easily move the fixing device and the object carrying it even when this object has large dimensions and / or a significant mass, the maintenance of the magnetic adhesion between the fixing device and the surface of the object in the second position reducing the efforts necessary to move the object carrying the fixing device relative to the other object and preventing a complete separation of the two objects.
[0009] The fixing device according to the invention may further comprise one or more of the following characteristics, taken in isolation or in any technically conceivable combination:
[0010] - the fixing device comprises a jack comprising a jack body and a cylinder piston movable relative to the cylinder body between a retracted position and an extended position, the magnet being mounted on the cylinder body, the magnetic attachment surface being in the first position when the cylinder piston is in the retracted position and being in the second position when the cylinder piston is in the extended position;
[0011] - the cylinder comprises at least one constraint element constraining the cylinder piston towards its retracted position;
[0012] - the fixing device comprises a device for moving the cylinder piston relative to the cylinder body between the retracted position and the deployed position, said displacement device comprising a device for injecting a fluid into a chamber delimited by the cylinder body and an internal face of the cylinder piston, the pressure of the fluid being arranged to generate a force greater than the addition of the force generated by the constraint element and the first magnetic adhesion force;
[0013] - the fixing device comprises at least one housing opening into a external surface of the cylinder body, at least one bearing being disposed in said housing, said bearing extending into the cylinder body in the retracted position and extending projecting from said cylinder body in the deployed position so as to form the magnetic attachment surface in the deployed position and allowing rolling of the magnetic attachment surface on the magnetic surface of the object in the second position of said magnetic attachment surface;
[0014] - the fixing device comprises a plurality of housings, a bearing being placed in each accommodation;
[0015] - the cylinder piston is fixed to the cylinder body by at least one fixing element secured to the cylinder piston and movable in translation in an orifice of the cylinder body, said fixing element abutting against an edge of said orifice in the deployed position of the cylinder piston so as to define the movement of the cylinder piston between the retracted position and the deployed position;
[0016] - the magnet is a permanent magnet, a semi-permanent magnet or an electromagnet;
[0017] - the fixing device comprises at least two adjacent magnets, the first magnetic adhesive force and the second magnetic adhesive force being generated by said magnets.
[0018] According to another aspect, the invention relates to a magnetic fixing system, comprising an object comprising a magnetic surface, a support and at least one fixing device as described above mounted on said support, said support being integral and immobilized on said magnetic surface in the first position of the magnetic fixing surface of the fixing device and being integral and movable on said magnetic surface in the second position of the magnetic fixing surface of the fixing device.
[0019] Other aspects and advantages of the invention will appear on reading the following description, given by way of example and with reference to the appended drawings, in which:
[0020] [Fig-1] - [Fig.l] is a schematic perspective representation of a system of fixing comprising a fixing device according to the invention,
[0021] [Fig.2] - [Fig.2] is a schematic perspective representation of a device magnetic fixing according to one embodiment of the invention,
[0022] [Fig.3] - [Fig.3] is an exploded schematic representation of the device of fixing of [Fig.2],
[0023] [Fig.4] - [Fig.4] is a schematic sectional representation of the device of fixing [Fig.2] in a first position, and
[0024] [Fig.5] - [Fig.5] is a schematic sectional representation of the device of fixing [Fig.2] in a second position.
[0025] With reference to Figs. 1 and 2, a magnetic fixing device 1 of a magnetic fixing system 2 is described for fixing an object (not shown) carrying the magnetic fixing device 1 to a magnetic surface 4 of another object. The magnetic fixing system 2 makes it possible, for example, to reversibly fix a tool, such as a robotic arm, on the magnetic surface 4, such as a metal plate, of an object, such as the hull of a naval vessel. It is however understood that the magnetic fixing system 2 can be used to fix any type of objects together, as long as at least one of the objects has magnetic properties allowing the magnetic fixing device 1 to be fixed thereon by magnetization.
[0026] In addition to the magnetic fixing device 1 and the surface 4 of the object, the magnetic fixing system 2 comprises in particular a support 6 on which the magnetic fixing device 1 is mounted and serving as a support 6 for the object to be fixed on the magnetic surface 4. As shown in [Fig.l], the magnetic fixing system 2 may comprise several magnetic fixing devices 1 mounted on the support 6, the number and the dimensioning of the magnetic fixing devices 1 depending on the object carried by the support 6, more particularly on its dimensions and / or its mass. More particularly, the number and the dimensioning of the magnetic fixing devices 1 are chosen so that the object carried by the support 6 is immobilized on the magnetic surface 4 and fixed thereto without detaching from it without external intervention on the magnetic fixing devices 1, as will be described in more detail later.
[0027] The fixing device 1 comprises at least one magnet 8 and a magnetic fixing surface 10 intended to adhere to the magnetic surface 4 of the object on which the fixing device is to be fixed thanks to the magnetic adhesion force generated by the magnet 8.
[0028] The magnet 8 is for example a permanent magnet, a semi-permanent magnet or an electromagnet arranged to emit a magnetic field towards the magnetic fixing surface 10. As more particularly visible in Figs. 3 to 5, the magnet 8 has for example a shape of a cylinder of revolution extending along an axis substantially perpendicular to the magnetic fixing surface 10. It is understood that other shapes of magnet 8 are conceivable as long as the magnetic field is emitted towards and beyond the magnetic fixing surface 10.
[0029] As shown in Figs. 2 and 3, the fixing device 1 may comprise several magnets 8, for example two magnets positioned next to each other so as to emit a magnetic field oriented towards the magnetic fixing surface 10. The fixing device 1 may comprise more than two magnets, for example three magnets, in particular when the magnetic adhesion force generated by the magnets must be particularly strong.
[0030] As will be described in more detail later, the magnet 8 is movable relative to the magnetic attachment surface 10 in order to modify the magnetic adhesion force between the magnetic attachment surface 10 and the magnetic surface 4 of the object.
[0031] For this purpose, the fixing device 1 comprises a jack 12 comprising a jack body 14 and a jack piston 16, movable relative to the jack body 14. The magnet 8 is integral with the jack body 14 so that the movement of the jack piston 16 relative to the jack body 14 causes a movement of the magnetic fixing surface 10 relative to the magnet 8, as visible in Figs. 4 and 5 showing the jack piston 16 in two different positions.
[0032] More particularly, the cylinder piston 16 is movable between a retracted position ( [Fig. 4]), corresponding to a first position of the magnetic fixing surface 10 in which the magnetic fixing surface 10 is brought closer to the magnet 8, and a deployed position ( [Fig. 5]), corresponding to a second position of the magnetic fixing surface 10 in which the magnetic fixing surface 10 is moved away from the magnet 8. In other words, the distance separating the magnet 8 from the magnetic fixing surface 10 is greater in the second position than this distance in the first position. In still other words, the air gap in the second position is greater than the air gap in the first position. This distance is for example measured between the face of the magnet 8 extending opposite the magnetic fixing surface 10. In the retracted position, the magnetic fixing surface 10 is for example in contact with the magnet 8.
[0033] The magnetic fixing surface 10 is formed by the part of the fixing device in contact with the magnetic surface 4 of the object. The magnetic fixing surface 10 can thus be carried by a part movable relative to the magnet between the first position and the second position or be formed by different parts of the fixing device 1, the distance of which from the magnet 8 is different depending on the position of the cylinder piston 16. Thus, according to the embodiment shown in the figures, in the retracted position, the cylinder piston 16 extends into the cylinder body 14 and the magnetic fixing surface 10 is formed by an external surface of the cylinder body 14.In the deployed position at least a portion of the cylinder piston 16 projects from the cylinder body 14 beyond the outer surface of the cylinder body 14 and the magnetic attachment surface 10 is then formed by the projecting portion of the cylinder piston 16, as will be described in more detail later.
[0034] Due to this modification of the distance, when the fixing device 1 is applied to the magnetic surface 4 of an object, the magnet 8 generates a first magnetic adhesion force between the magnetic fixing surface 10 and the magnetic surface 4 of the object in the first position which is greater than the second magnetic adhesion force generated by the magnet 8 in the second position. Indeed, in the second position, the magnet 8 extends at a greater distance from the magnetic surface 4 which is therefore less subject to the magnetic field of the magnet 8 than in the first position, in which the magnet 8 extends at a lesser distance from the magnetic surface 4. In other words, the attachment of the attachment device 1 to the object carrying the magnetic surface 4 is less robust in the second position than in the first position. It should be noted, however, that the first magnetic force and the second magnetic force are arranged so that the attachment device 1 and the object carrying it remain secured to the object carrying the magnetic surface 4 in the absence of additional external stress. In other words, the reduction in the magnetic adhesion force in the second position does not cause the object carrying the attachment device 1 to become detached from the object carrying the magnetic surface 4, the air gap being sized to maintain a sufficient magnetic flux to avoid this detachment.The decrease in the magnetic adhesion force between the first position and the second position has the effect of making the fixing device 1 and the object which carries it movable, for example by sliding, on the magnetic surface 4. Thus, in the first position, the first magnetic adhesion force is arranged to ensure fixing of the fixing device 1 on the magnetic surface 4 and to immobilize the fixing device 1 relative to the magnetic surface 3 and, in the second position, the second magnetic adhesion force is arranged to ensure fixing of the fixing device 1 on the magnetic surface 4 and to allow movement of the fixing device 1 on the magnetic surface 4.
[0035] Consequently, when the object carrying the fixing device 1 must be repositioned on the object carrying the magnetic surface 4, it is sufficient to move the magnetic fixing surface 10 from the first position to the second position, then to move the object on the magnetic surface 4 to the desired position and to move the fixing surface 10 again from the second position to the first position to immobilize the object in its new position on the magnetic surface 4. The movement is carried out without having to separate the object carrying the fixing device 1 from the magnetic surface 4. It is understood that when the object carries several fixing devices 1, all the fixing devices are placed in the second position to allow the movement of the object on the magnetic surface 4.It will further be noted that, when it is desired to separate the two objects, the force required to enable this separation is reduced by placing the fixing device(s) in the second position since the magnetic adhesion force to be overcome to separate the objects is lower in this second position.
[0036] In order to facilitate the movement of the fixing device 1 on the magnetic surface 4, the fixing device 1 comprises, according to one embodiment, at least one bearing 18 carried by the cylinder piston 16 and movable therewith between the first retracted position and the second deployed position, as visible in Figs. 4 and 5. In the retracted position, corresponding to the first position of the magnetic fixing surface 10, the bearing 18 extends into the cylinder body 16 and the magnetic fixing surface 10 is formed by an outer surface of the cylinder body 16, as previously described. In the deployed position, corresponding to the second position of the magnetic fixing surface 10, a portion of the bearing 18 projects from the cylinder body 16 beyond the outer surface thereof to be in contact with the magnetic surface 4 of the object so that the magnetic fixing surface 10 is then formed by the portion of the bearing 18 in contact with the magnetic surface 4. Thus, in the second position of the magnetic fixing surface 10, the contact between the fixing device 1 and the magnetic surface 4 is a rolling contact facilitating the movement of the fixing device 1 on the magnetic surface 4 when the second magnetic adhesion force is generated for the magnet 8 and when the fixing device 1 is movable on the magnetic surface 4.
[0037] The bearing 18 is for example arranged in a housing 20 delimited by the cylinder piston 16 and / or the cylinder body 14, the housing opening into the external surface of the cylinder body 14 in order to allow the passage of a part of the bearing 18 projecting from the external surface of the cylinder body 14. According to the embodiment shown in the figures, the housing 20 is formed by a groove extending in an external face 22 of the cylinder piston 16 on the periphery thereof. This housing 20 receives a plurality of bearings 18 formed by balls movable in rotation in the housing 20. As a variant, several housings 20 are provided, each housing receiving a bearing 18 movable in rotation in the housing.
[0038] To enable the cylinder piston 16 to be moved between the retracted and extended positions, the securing device includes a device for moving the cylinder piston 16 relative to the cylinder body 14 for moving the cylinder piston 16 from the retracted position to the extended position and at least one constraining element 24 constraining the cylinder piston 16 toward the retracted position when the moving device is not activated.
[0039] The displacement device comprises a device 26 for injecting a fluid into a chamber 28 delimited by the cylinder body 14 and an internal face 30 of the cylinder piston 16, opposite the external face 22. The fluid, for example air, injected into the chamber 28 increases the volume of the chamber 28 and causes the displacement of the cylinder piston 16 by increasing the distance between the internal face 30 of the cylinder piston 16 and the bottom of the chamber 28 formed by a wall of the cylinder body 14, as shown in [Fig. 5]. Thus, the increase in the volume of the chamber 28 causes the displacement of the external face 22 of the cylinder piston 16 and the bearing(s) 18 towards the deployed position. The pressure of the fluid injected into the chamber 28 as well as the surface of the internal face 30 of the piston are dimensioned to overcome the first magnetic adhesion force and the force exerted by the constraint element 24 in order to allowing the cylinder piston 16 to move from the retracted position, in which the first magnetic adhesion force is generated, to the extended position.
[0040] A fluid inlet 32 provided in one of the magnets and connected to a fluid source, such as an air pump or the like, may be provided to completely activate or deactivate the magnet 8, which is then a controllable magnet.
[0041] In order to delimit the movement of the cylinder piston 16 between the deployed position and the retracted position, the cylinder piston 16 is for example mounted on the cylinder body 14 by at least one fixing element 34 secured to the cylinder piston 16 and mounted to move in translation in an orifice 36 of the cylinder body 14 between the retracted and deployed positions. In the deployed position, the fixing element 34 abuts against an edge of the orifice 36 and thus prevents further movement of the cylinder piston 16 beyond the deployed position. Thus, by choosing the length of the fastening element 34, measured along the direction of movement of the fastening element 34 between the retracted and extended positions, the distance between the magnetic fastening surface 10 and the magnet 8 in the second position can be adjusted, thereby adjusting the value of the second magnetic adhesive force.The fastening element 34 is for example a screw, screwed into the cylinder piston on one side of the orifice 36 and the head of which extends to the other side of the orifice 36 and abuts against an edge of the orifice in the deployed position, as shown in [Fig. 5]. As shown in [Fig. 3], several fastening elements 34 are for example provided between the cylinder body 14 and the cylinder piston 16.
[0042] The constraint element 24 is for example formed by a helical spring mounted around the fixing element 34 and bearing against the cylinder body 14. In the deployed position, the spring is compressed by the head of the fixing element 34, as shown in [Fig. 5] and returns the cylinder piston 14 to its retracted position by relaxing when the pressure of the fluid in the chamber 28 is released, as shown in [Fig. 4].
[0043] The fixing device 1 described above can therefore be used to fix an object to another object firmly and by immobilizing the objects relative to each other in the first position and by allowing a movement of one of the objects relative to the other while maintaining the adhesion between these objects in the second position. Such a fixing device 1 is particularly useful for allowing the positioning and repositioning of a bulky and / or heavy object on a large magnetic surface, the movement between the different positions being facilitated in the second position.
Claims
Claims
1. Magnetic fixing device (1), comprising a magnetic fixing surface (10), intended to be applied to a magnetic surface (4) of an object to be fixed on said object, and at least one magnet (8), the magnetic fixing surface (10) extending at a variable distance from said magnet (8) between a first position, in which the magnet (8) is brought closer to the magnetic fixing surface (10) to generate a first magnetic adhesion force immobilizing the magnetic fixing surface (10) relative to the magnetic surface (4) of the object, and a second position, in which the magnet (8) is moved away from the magnetic fixing surface (10) to generate a second magnetic adhesion force, lower than the first magnetic adhesion force,said second magnetic adhesive force maintaining adhesion between the magnetic attachment surface (10) and the magnetic surface (4) of the object while allowing movement of the magnetic attachment surface (10) on the magnetic surface (4) of the object.,
2. A fastening device according to claim 1, comprising a cylinder (12) comprising a cylinder body (14) and a cylinder piston (16) movable relative to the cylinder body (14) between a retracted position and an extended position, the magnet (8) being mounted on the cylinder body (14), the magnetic fastening surface (10) being in the first position when the cylinder piston (16) is in the retracted position and being in the second position when the cylinder piston (16) is in the extended position.
3. A fastening device according to claim 2, wherein the cylinder (12) comprises at least one constraining element (24) constraining the cylinder piston (16) towards its retracted position.
4. A fixing device according to claim 3, comprising a device for moving the cylinder piston (16) relative to the cylinder body (14) between the retracted position and the deployed position, said moving device comprising a device (26) for injecting a fluid into a chamber (28) delimited by the cylinder body (14) and an internal face (30) of the cylinder piston (16), the pressure of the fluid being arranged to generate a force greater than the addition of the force generated by the constraint element (24) and the first magnetic adhesion force.
5. A fixing device according to any one of claims 2 to 4, comprising at least one housing (20) opening into an external surface of the cylinder body (14), at least one bearing (18) being arranged in said housing (20), said bearing (18) extending into the cylinder body (14) in the retracted position and extending projecting from said cylinder body (14) in the deployed position so as to form the magnetic fixing surface (10) in the deployed position and to allow rolling of the magnetic fixing surface (10) on the magnetic surface (4) of the object in the second position of said magnetic fixing surface (10).
6. A fastening device according to claim 5, comprising a plurality of housings (20), a bearing (18) being disposed in each housing (20).
7. A fixing device according to any one of claims 2 or 6, wherein the cylinder piston (16) is fixed to the cylinder body (14) by at least one fixing element (34) integral with the cylinder piston (16) and movable in translation in an orifice (36) of the cylinder body (14), said fixing element (34) abutting against an edge of said orifice (36) in the deployed position of the cylinder piston (16) so as to define the movement of the cylinder piston (16) between the retracted position and the deployed position.
8. A fixing device according to any one of claims 1 to 7, wherein the magnet (8) is a permanent magnet, a semi-permanent magnet or an electromagnet.
9. A fixing device according to any one of claims 1 to 8, comprising at least two adjacent magnets (8), the first magnetic adhesive force and the second magnetic adhesive force being generated by said magnets (8).
10. A magnetic fixing system comprising an object comprising a magnetic surface (4), a support (6) and at least one fixing device (1) according to any one of claims 1 to 9 mounted on said support (6), said support (6) being integral and immobilized on said magnetic surface (4) in the first position of the magnetic fixing surface (10) of the fixing device (1) and being integral and movable on said magnetic surface (4) in the second position of the magnetic fixing surface (10) of the fixing device (1).