DEVICE FOR SLIDING SUPPORT

Abstract

A supporting device (MC) is described to slidingly support, and linearly move along an axis (X), an object such as e.g. a leaf.

A magnetic return force generated by the cooperation of a magnetic flux generator (54, 56) and an element (10) reactive to the magnetic field, develops.

The element is able to slide relative to the axis (X) during the movement of the object, and has a cross-section (62) which, seen in a plane orthogonal to the axis (X), has a width that varies along the length of the first element (10) parallelly to said axis (X).

Claims

1. Supporting device (MC) to slidingly support, and linearly move along an axis (X), an object such as e.g. a leaf, comprising: an empty channel (58) extending parallel to the axis (X), a magnetic flux generator (54, 56) for creating a magnetic flux that crosses a segment of the empty channel with magnetic field lines which are all equiverse, a first element (10), reactive to the magnetic field, which is mounted in the empty channel and which extends along said axis (X), the first element being able to slide relative to the channel parallel to the axis (X) during the movement of the object, wherein the first element (10) in correspondence of said channel segment has a cross-section (62) which, seen in a plane orthogonal to the axis (X), has a dimension (L) along the width of the channel (58), wherein said dimension has a value (L) that varies along the length of the first element (10) parallelly to said axis (X).

2. Device (MC) according to claim 1, wherein the generator (54. 56) is inserted inside a magnetic circuit (52) configured for conveying the magnetic flux so that the flux passes through the empty channel, and defining said channel (58).

3. Device (MC) according to claim 1, wherein the generator comprises two rows (54) of magnets (56) arranged uniformly along, and parallel to, the axis (X) for determining between the two rows an empty space crossed by all-equiverse magnetic field lines coming out from a row and entering the other.

4. Device (MC) according to claim 1, wherein the first element (10) comprises a first and a second contiguous portion (60, 62) which extend along the axis (X), wherein in the first portion (60) said cross-section is wider than the respective cross-section of the other portion (62).

5. Device (MC) according to claim 4, wherein the first portion (60) is along the axis (X) at least as long as the channel's segment with flux lines.

6. Device (MC) according to claim 4, wherein the first portion (60) has a length, along the axis (X), equal or slightly lower than the channel's segment (58) with flux lines.

7. Device (MC) according to claim 1, wherein the cross-section of the first element (10), along a direction orthogonal to an imaginary plane (P1) that contains the two rows of magnets and/or the flux lines that cross the channel, has a width which along said orthogonal direction is decreasing as it is farther away from the plane (P1).

8. Device (MC) according to claim 1, comprising a second pair of equal, spaced and parallel rows of magnets (70) arranged parallel to the axis (X) for creating in the middle of the two rows an empty space (72) crossed by magnetic field lines emerging from one row and entering the other, and a second element (74), reactive to the magnetic field, which extends parallel to the axis (X) between the two rows of the second pair, the rows of the second pair and the second element (74) being able to slide relatively parallel to the axis (X) to move the object between two positions, wherein the second element (74) in correspondence of said space (72) has a cross-section which, seen in a plane orthogonal to the axis (X), remains constant along the axis (X) but along a direction orthogonal to an imaginary plane (P2) which contains the two rows, direction along which a load (W) acts, has a width which along said orthogonal direction is decreasing as it is farther away from the plane (P2).

9. Device (MC) according to claim 8, wherein the magnets (70) of the second pair are installed so that inside the second space (72) the field lines have alternate direction.

10. Door or leaf of refrigerating unit comprising a device according to claim 1.

Description

[0049] The advantages of the invention will be clearer from the following description of a preferred embodiment, referring to the enclosed drawing wherein:

[0050] FIG. 1 shows a three-dimensional exploded view of a device;

[0051] FIG. 2a, 2b show some parts of the device in plan view;

[0052] FIG. 3 shows a vertical cross-section of the device as assembled.

[0053] In the figures, same numbers indicate identical or conceptually similar parts; the letters N and S indicate North and South magnetic poles respectively; and the arrows indicate magnetic flux lines.

[0054] The MC device works e.g. to slidably support a door 20 (not shown) along an X axis.

[0055] The MC device comprises a fixed rectilinear track 10 and a skid 50, movable on the track 10, which can slide relatively to each other parallel to the X axis while the door is moving. In the example shown the door would be mounted on the skid 50, but the MC device also contemplates reversing the roles of rail 10 and skid 50, so that the first moves and the second remains fixed.

[0056] The skid 50 comprises a body 52, having an inverted-U cross-section, inside which there are mounted two identical, parallel and spaced rows 54 of magnets 56 arranged uniformly alongside—and parallel to—the X axis. Thus between the separation of the rows 54 there is created an empty channel 58 crossed by lines of magnetic field being all equiverse and coming out of a row 54 and entering in the other (see scheme in FIG. 2a, 2b).

[0057] The fixed track 10 is mounted inside the channel 58.

[0058] The part of the track 10 placed at the channel 58 exhibits a cross-section that, seen in a plane orthogonal to the X axis and measured on the line joining the rows 54 (see plane P1 in FIG. 3), has a width L which varies as a function of the position along the X axis.

[0059] The track 10 comprises a first portion 60 and a second portion 62, and said cross-section is larger in the first portion 60 and smaller in the second portion 62.

[0060] In the illustrated example the first portion 60 has length along the X axis at least equal to that of the rows 54. In general, the length of the portion 60 must be longer than the rows 54 only if it is desired to guarantee an equilibrium condition at the door's complete opening, otherwise in general this geometric feature is not necessary.

[0061] There is a discontinuity between the cross-sections of portions 60, 62 at a point P. This discontinuity can be abrupt, like a step, or it can be gradual as a ramp. A magnetic force develops at point P between the cross-sections of portions 60, 62 and the magnetic field generated by the rows 54 of magnets.

[0062] At point P, and only at that one, a force develops tending to relatively shift the track 10 and the rows 54 along the X axis, so that the segment 60 of the track 10 with a smaller cross-section gets out of the empty channel 58, or so that the segment 60 with smaller cross-section is no longer hit by magnetic field lines.

[0063] The situation is shown in FIGS. 2a. 2b.

[0064] When only the larger cross-section 62 (FIG. 2a) is inside the channel 58, there is no return force.

[0065] When (FIG. 2b) the cross-section of portion 60 is moved into the channel 58 (toward the left in the drawing), at the point P a return force F is created which tends to oppose the change of position and to bring the system back as in FIG. 2a (towards the right in the drawing).

[0066] If for example the relative position between the track 10 and the rows 54 of FIG. 2a corresponds to the closed-door position, upon opening the door (FIG. 2b) the MC device generates a force F which returns the door to the closed position.

[0067] The force F has a nearly constant magnitude, independently of the position of the point P between the rows 54.

[0068] The variation in cross-section entails a variation in reluctance of the magnetic circuit; the magnitude of the force remains almost constant since it is linked to the reluctance variation, which is constant too.

[0069] Clearly, everything also applies to a movement along the other direction on the X axis (that is, turning FIGS. 2a, 2b by 180°), being enough that the track 10 has a symmetrical shape with respect to a plane orthogonal to the X axis. It is the case of FIG. 1, in which a magnetic force F tending to bring back the skid 50 to the center of the track 10 is generated, because the track 10 has two points of discontinuity for the cross-sections of portions 60, 62 which are far apart at least as the length along X of the skis 50.

[0070] Preferably the MC device also generates a force to slidingly support the skid 50 on the track 10.

[0071] To generate such force that opposes the load W, e.g. the track 10 in correspondence of the cross-sections of portions 60, 62 comprises a T-shaped portion or a portion with the shape of H or +, or in general such cross-section, along a direction orthogonal to an imaginary plane P1 containing the two rows 54, has decreasing width as it is farther away from the plane. In other words, preferably the cross-sections of portions 60, 62, along a direction orthogonal to the plane P1, have a width witch is decreasing as it is farther away from the plane.P1. So this portion of the MC device also generates load-bearing force.

[0072] To increase the supporting force, the skid 50 preferably comprises a second pair of equal, parallel and spaced-apart rows 70 of magnets arranged parallel to the X axis to create between the two rows 70 a second empty space 72 crossed by magnetic field lines coming out of one row 70 and entering the other. In the space 72 there is a second element 74 of the track 10 which is reactive to the magnetic field and extends parallel to the X axis between the two rows 70.

[0073] The cross-section of the track 10 that slides inside the space 72 exhibits a cross-section 76 which, seen in a plane orthogonal to the X axis, remains constant along the X axis but, along a direction orthogonal to an imaginary plane P2 that contains the two rows 70, has width which decreasing as it is farther away from the plane P2.

[0074] In the illustrated example, the cross-section 76 is comprised in a portion having the shape of a +. Other variants envisage e.g. a cross-section 76 in the shape of a T or H, and/or the use of different material for various parts of the cross-section 76.

[0075] As illustrated, it is preferred that the cross-sections 60, 62 and the cross-section 76 belong to a single piece, e.g. a section-bar for simplicity of construction, or in any case develop from the same plane.

[0076] By the physical principles described in PCT/IB2017/052588, when the cross-section 76 moves away from plane P2 a magnetic reaction force is created, directed orthogonally to the plane P2 and towards the space 72, which tends to bring the cross-section 76 back inside the space 72. Thus the weight W of the object is opposed.

[0077] Always for the same reason, the variation along the direction of the load entails a variation of the reluctance that generates a magnetic reaction force which tends to bring the system back into the minimum reluctance configuration. Therefore an equilibrium position is reached in which the magnetic force balances the load.