US3346993A

US3346993A - Magnetically supported sliding doors and panels

Info

Publication number: US3346993A
Application number: US551005A
Authority: US
Inventors: Waldo O Johnson
Original assignee: WEATHER SEAL Inc
Current assignee: WEATHER SEAL Inc
Priority date: 1966-05-18
Filing date: 1966-05-18
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17

Description

Oct. 17, 1967 W. O. JQHNSON MAGNETICALLY SUPPORTED SLIDING DOORS AND PANELS Filed May 18, 1966 2 Sheets-Sheet 1 FIG.!

FIG.5

FIG. 6

INVENTOR. WALDO O. JOHNSON 0d. 17, 1967 w, 0. JQHNSQN 3,346,993

MAGNETICALLY SUPPORTED SLIDING DOORS AND PANELS Filed May 18, 1966 2 Sheets-Sheet 2 9 v INVENTOR WALDO o. JOHNSON ATTORNEYS BY2 2 2: v

United States Patent 3,346,993 MAGNETICALLY SUPPORTED SLIDING DOQRS AND PANELS Waldo 0. Johnson, Wooster, Ohio, assignor to Weather- Seal, lire, Barherton, Ohio, a corporation of Ohio Filed May 18, 1966, Ser. No. 551,005 8 Claims. (Cl. 4409) ABSTRACT OF THE DISCLOSURE Panels, windows, doors or the like are slidably positioned in a vertical plane for movement only in such vertical plane. The door or other article is supported by means of pairs of elongate permanent magnets attached to the door and to an associated frame means whereby the magnets, extending at least substantially the widths of the door and frame, support or float the door for lateral movement.

This application is a continuation-in-part of my prior US. application Ser. No. 488,073 filed Sept. 17, 1965, now abandoned.

The present invention relates to a novel and improved means for supporting sliding doors, panels and the like, and it particularly relates to the use of elongate, magnetized flexible strips for use in supporting sliding doors, windows and the like.

Heretofore there have been various efforts made to provide permanently magnetized flexible plas ic or elastomer strips. The B. F. Goodrich Company of Akron, Ohio, U.S.A., makes quite a few strips commercially and typical flexible, permanently magnetized strips have been adopted commercially, as for use in sealing of self-closing refrigerator doors and the like. Such strips also have been used in some types of magnetic catches and the like. Various patents have been issued on these elastomer magnetic strips.

The general object of the present invention, broadly speaking, is to provide a novel and improved means for supporting sliding doors, panels, windows and the like, wherein a pair of permanently magnetized flexible strips, having elongate poles extending the length thereof, are positioned with their like elongate poles in opposed relation on the door, window assembly, or the like, to aid in supporting or fully support the door, window or other sliding member by providing a lifting action thereon.

Another object of the invention is to provide a new and improved sliding door or other closure unit wherein at least a part of the weight of the door is supported by magnetic means and the forces set up thereby to facilitate movement of the closure unit.

Another object of the invention is to provide a sliding door or similar member with positioning means that position such door with relation to its support means for only lateral, horizontal sliding movement and for limited vertical movement, but with the door being retained against any movement in a direction perpendicular to a plane defined by the door.

A further object of the invention is to use opposed and repelling magnetic forces for supporting a door or other closure member to facilitate sliding movement of the door and affect a lightening of the door for movement purposes.

The foregoing and other objects and advantages of the present invention will be made more apparent as the specification proceeds.

Attention now is particularly directed to the accompanying drawings, wherein:

FIG. 1 is an elevation of a typical sliding door or panel installation of the invention;

FIG. 2 is a fragmentary enlarged vertical section, partially broken away, of the panels of FIG. 1 when they overlap;

FIG. 3 is an end view of one plastic strip that may be used in the invention, and the magnetic field of the strip is indicated;

FIG. 4 is an end perspective View of the strip of FIG. 3, with the magnetic field set up thereby being indicated;

FIG. 5 is an end view of another type of a permanently magnetized magnetic strip with the polarity and magnetic field set up thereby being indicated thereon;

FIG. 6 is an end view of the plastic strip of FIG. 5;

FIG. 7 is an enlarged vertical section, partially broken away, of a modified structure of the invention;

FIG. 8 is a fragmentary vertical section of a further modification of the invention showing just the upper end of a sliding door; and

FIG. 9 is a fragmentary vertical section of yet a further modification of the invention.

When referring to corresponding members shown in the drawings and referred to in the specification, corresponding numerals are used to facilitate comparison therebetween.

The present invention, generally speaking, as to one embodiment thereof, relates to a vertically positioned, horizontally slidable door, window, panel or the like wherein a combination is provided of a frame member, a panel operatively engaging the frame member to permit only relative lateral and limited vertical movement therebetween, and individual permanently magnetized, elongate, strip means secured to adjacent portions of each of said frame member and said panel, which strip means are immediately adjacent each other in superimposed vertical relation and have longitudinally extending poles provided thereon, whereby the magnetic action between the strips provides a lifting action on the panel.

Reference now is made to the details of the structure shown in the drawings, and a pair of vertically positioned, horizontally slidable panels, doors, windows or the like, are indicated by the numerals 1 and 2, respectively. These panels 1 and 2 are positioned in any suitable frame means 3 including a top member 4, and a bottom member 5. The top member 4 includes a pair of downwardly extending guide members or flanges 6 and 7 provided thereon, while the bottom frame member 5 has a pair of upwardly extending guide means or flanges 8 and 9 formed thereon and extending the length thereof, in parallel spaced relation. These

frame members

4 and 5 are usually made from metal and usually are formed to a desired extruded shape, which shape can be varied as desired for providing a frame means suitable for use in practice of the present invention. Normally these frame means are formed from a nonmagnetic material, such as aluminum.

The drawings also clearly show that the panels, doors, windows or the like 1 and 2, in this particular instance, each include a top rail 10 and a bottom rail 11 and, usually, a center panel 12, which in this instance is made from glass. The center panel is secured to the top rail 10' and the bottom rail 11 in any suitable manner, as by the combination of plastic sealing strips 13 with associated portions of the rails and with such plastic strips being used to position the center panel 12 in the panel unit 2 as shown.

Usually the top rail 10 has a pair of upwardly extending flanges or

legs

14 and 15 formed thereon, which legs are of such size as to be positioned laterally outwardly of the guides or flanges 6 and 7 formed on the top member 3 in telescoped relation thereto. Usually, some sealing strips or means, such as fabric pile strips 16, are carried by each of the

legs

14 and 15 for sealing slidable engagement with the guides or flanges 6 and 7, but where some limited vertical movement is permitted between the center panel 2 and its associated top frame means 4.

The bottom rail 11 may be the same, or substantially the same, in cross sectional contour as the rail 10.

Legs

17 and 18 are provided on the bottom rail 11 to lie immediately adjacent and laterally externally of the rails or flanges 8 and 9 and suitable sealing means 18a can be carried by each one of these legs to aid in providing substantially an airtight seal between the bottom rail 11 and the bottom frame member 5, but to permit ready sliding movement therebetween and usually limited vertical movement between such members.

It is an important feature of the present invention that elongate permanent magnets, such as flexible metallized strips, are used to aid in the support of, or to support, or float the panels 1 and 2 in the window or door assembly of the invention to facilitate sliding movement of these members in relation to the frame means provided. Thus, the drawings show that a permanently magnetized flexible strip 19 is suitably carried by the. bottomframe member 5, usually being snugly received between the flanges or guides 8 and 9 thereon and usually extending the height of these flanges, or being positioned at the tops of the flanges and extending the length of the bottom frame member 5 in the assembly. A similar flexible strip 2t) is secured to the bottom rail 11 at a lower end portion thereof and exposed so as to lie immediately adjacent and in superimposed relation to the strip 19. Usually the strip 20 extends the length of the bottom rail 11. This strip 20 is secured to the bottom frame member in any suitable manner, as by use of short legs or flanges 21 that may be formed as an integral extruded unit with the bottom rail '11 and have the end portions thereof peened or otherwise deflected inwardly towards each other to engage the strip 20. Ohviously these

flexible strips

19 and 20 can be engaged with and carried operatively by the bottom frame member 5 and the bottom rail 11 in any desired manner.

FIG. 2 of the drawings best shows that the magnet means, or strip 20 may have a pair of elongate permanent poles provided at the lower lateral margins thereof and extending the length of the strip, while the strip 19 has a pair of elongate permanent poles formed at the upper margin thereof, as indicated in the drawings. It will be seen that these opposed poles in the

strips

19 and 20 are like poles and that a repelling magnetic force will be set up therebetween and, since the panels 1 and 2 cannot move any appreciable distance perpendicular to the vertical plane defined by the panels, these opposing magnetic forces cause a lifting action to be provided on the panels 1 and 2 to facilitate sliding the panels, doors or the like laterally on their support means. FIG. 2 shows how the magnetic action actually floats the panel '1 in a mounting frame. Weak north and south poles are formed in the

strips

19 and 20 and are indicated at N and S. The strips are made from any suitable :material, usually an elastomer, and it contains a large quantity of particles of a magnetizable material, such as barium ferrite (BaFe The strength of the strip can be varied by the amount of barium ferrite in it and by the power of the magnetization of such material.

FIGS. 3 and 4 of the drawings show a strip 20a that can be used in the invention and it has a strong north pole and a strong south pole formed at the upper and at the lower margins thereof, respectively. These poles form fields as indicated by the continuous electro-magnetic lines shown in FIG. 3. Hence, the fields set up by a pair of the strips 20a can be opposed to each other and provide the desired lifting action in the construction of the invention.

FIGS. and 6 show another plastic strip 2% wherein a north pole is formed at one lateral margin of the strip and the opposite, or south pole is formed at the other lateral margin, or vertically extending side of the plastic strip. This is another type of a polarity that can be used in these strips, which usually are of rectangular shape in cross section, to provide effective magnetic support in doors and other sliding members. Such poles are still considered to be in vertical alignment in assemblies of the invention.

It will be realized that the

magnetic strips

19 and 20, or equivalents, are of conventional construction and are made in accordance with commercial practices by, for example, The GoodrichCompany, or others, which strips may be of any suitable elastomer carrier composition and are so processed by the manufacturer as to provide elongate permanently magnetized poles in the resilient or flexible strips from the metallic, or magnetizable particles embedded in the strips.

It will be realized that only one sliding door or panel may be mounted upon frame means in accordance with the invention so as to be moved to and from a closed and open position, as desired, and that one fixed and. one movable panel may be positioned in the apparatus, or two movable panels, doors, windows or the like can be posi+ tioned in the assemblies of the invention.

When two relatively slidable doors are associated with each other, normally they are spaced depth-wise in the apparatus a sufficient distance that there is no overlap of any appreciable nature in the magnetic fields provided in.

the supporting means for such doors, windows or the like. FIG. 2 shows that the construction of the panel 2 and the supporting means therefor may be about the same or the same as the means used to position the panel 1. In the drawing,

flexible strips

30 and 31 are shown with opposed centrally located poles extending the length of the adjacent surfaces of the strips. The strip 30 may be cemented, or otherwise secured, to a rib 32 on a bottom rail 33.

PEG. 7 of the drawings shows a modified sliding door, window, panel, or the like with the entire assembly being indicated by the numeral 1a. In this instance, a bottom frame member 40 is provided that positions a flexible, permanently magnetized strip 41 in the upper portion of the bottom frame member 40 and it may have the elongate poles as indicated in the drawings. In this instance, an upper frame member 42 is shown that is of suitable shape and is adapted to be attached to a support for the window or panel In and a removable dependent section 43 is provided extending, usually, the length of the upper frame member 42 and adapted to form an enclosure therewith. The upper frame section 43 may be secured to a margin of the upper frame member 42 by any suitable member (not shown) to extend downwardly therefrom to form an enclosure with a dependent leg 45 provided on the upper frame member 42. An elongate slot 46 is formed between adjacent support surfaces, or

shelves

47 and 48 provided on the leg 45 and the upper frame section 43, respectively. In this instance, a door, panel, window, or

the like 49 is provided and it has a lower or bottom sashv rail 50 formed thereon, or secured thereto that carries a magnetized strip 51 in an open lower portion thereof, which strip 51 is positioned vertically superimposed over the strip 41. The strip 51 preferably extends the length of the window, or the like 49 to provide support for this window or equivalent member. An upper rail 52 is provided for the window 49 and it has a T-shaped extension 53, or equivalent member suitably secured to or formedas a unit with the upper rail 52. The T-shaped extrusion 53 has the stem thereof extending through the slot 46 and with the upper end thereof being received between the leg 45 and the dependent section 43 of the upper frame member 42. Thus, in this instance, resilient, permanently magnetized elastomer strips 54 and 55 are suitably secured to and carried by the

surfaces

47 and 48, respectively, which strips have the elongate permanently magnetized poles, as indicated, or equivalents, provided therein and extending the length thereof. Then to obtain further support action for the panel or window 49, a pair of additional permanently magnetized

elongate strips

56 and 57 are suitably secured to the lower surfaces of the upper section of the T-shaped extension 53 carried by the upper rail 52.

It will be seen that the elongate poles provided in the

strips

54 and 55 and that these adjacent strips are superimposed with relationship to each other and the poles are in vertical alignment. Again, the panel or window 49 is retained against any appreciable lateral movement by sealing

strips

58 and 59 that are carried by lower marginal portions of the upper frame section 43 and of the leg 45 on the upper frame member to brush against the upper rail 52 of the window to aid in retaining such member against movement normal to the plane thereof and to aid in providing a sealed engagement between these members. Such sealing strips can be made from a wool pile material, or other suitable substance to provide a sealing action with a minimum of frictional engagement between the engaged surfaces. Similar sealing strips 60 and 61 may be carried by the lateral margins of the upper section of the T-shaped extension 53 and engage adjacent walls on the upper frame member 42 and the frame section 43. Yet additional sealing strips 62 and 63 can be carried by the window 49 at the lower marginal portion of the bottom rail 50" thereon to permit substantially sealed sliding movement between the panel or window 49 and its associated support means.

It should be realized that the magnetic repelling action provided by the elongate, permanently magnetized flexible strips of the invention can be sufficient so as to actually float the window, panel, door or the like, upon its associated support and positioning means, as such movable member is retained against movement normal to the plane which it defines.

It also should be noted that just the repelling support means provided in the upper end or portion of the window 49, as shown in FIG. 7 may be utilized in some instances to position a sliding member for improved support action in accordance with the principles of the invention. The use of the repelling forces at the top and/ or at the bottom of the window, panel, door or the like, is dependent upon the weight of the supported member, and even relatively heavy sliding doors or panels can be literally floated by the use of the pairs of opposed magnetic means, or equivalents, as shown in FIG. 7, or by use of a widened bottom rail, similar to the rail 50, which may position a plurality of flexible elongate magnets, or plastic strips in parallel relation directly above companion strips carried by the bottom frame 48 in other assemblies of the invention. In such cases, several of the strips, preferably like the

strips

19 and 20, would be positioned beside each other with metal partitions therebetween to provide N.S., N.S. etc. relationship between the elongate poles of the different strips in the side-by-side strips carried by one of the members and be immediately adjacent like elongate poles N.S., N.S. etc. in the opposed member.

FIG. 8 shows a further modification of the invention wherein a window, panel, door, member, or the like 1b is shown and in this instance, is associated with an upper frame member 70 that is secured to a suitable support. The upper frame member 7 has a resilient strip 71 with elongate permanently magnetized poles provided therein, which strip is secured to a depending portion of the frame member and is exposed at a lower portion thereof. In this instance, an upper sash rail 72 is provided for the window 1b and such rail carries a flexible, permanently magnetized strip 73 therein in any suitable manner. In this instance, the permanent poles provided in the

strips

71 and 73 are in vertically superimposed relationship but with unlike poles being provided in the adjacent portions of the strips to set up an attractive magnetic action for support of the window 112. Best support action for the member 1b is obtained when some limited air space is provided between the adjacent surfaces of the

strips

71 and 73, as by predetermination of the attraction forces to be slightly less in weight lifted than the weight of the member 1b. The lower end of the member 1b may, for example, be supported by a roller bearing assembly in a member that is resiliently pressed up towards the lower edge of the member 1b.

FIG. 9 shows yet a further modification of the window support means of the invention and a sliding door, panel or window assembly is indicated as a whole by the numeral 10. In this instance, a wooden frame window is shown and it is supported by the magnetic forces set up in opposed resilient plastic strips 81 and 82, like the strips 19 and 26, positioned in vertically superimposed and adjacent relationship in the lower portion of the window 80 and its support means.

The window 80 preferably has an upper sash rail 83 that has a metal edge strip 84 suitably secured thereto, which edge strip usually is of extruded construction to provide the special metal shape shown, and this metal edge strip 84 may support a member, such as a plurality of plastic plugs 85 in longitudinally spaced portions thereof. These plugs 85 have a suitable sealing strip, such as one made from wool pile and indicated at 86 supported thereby and exposed for engagement with a dependent section 87 formed in a header, or guide member 88 that is suitably attached to the frame means for the window 80. The window 80 is positioned in any suitable manner for limited vertical movement and for lateral sliding movement in the apparatus of the invention and such window is retained against any appreciable movement in a direction normal to the plane defined by the window 80. A second window 89 is also slidably positioned in the assembly 1c and it may be magnetically supported, if desired. However, usually only the inner window 80 is frequently moved in the assembly shown. A resilient back-up pad 90 supports the guide member 88 to facilitate window placement and removal.

If desired, the invention may also be practiced by use of elongate permanent metal or ceramic magnets of U- shape in section with permanent poles at the ends of the magnet legs, or other suitable elongate permanent metal magnets can be used. Then opposed like poles would be provided by the vertical alignment of the opposed, usually equal strength magnets of any suitable composition and size in the movable member and its frame. In some instances, the magnetic strips, such as the

strips

19 and 20, may have a magnetic metal strip secured to the lower surface or back of the strip 19 and the upper surface of the strip 20. Such metal backing strips may be flexible, if desired.

Obviously, any metal members used in the apparatus, except for the magnets, or magnetic means, will be made from non-magnetic material. The magnetic forces obtained can also be varied by changing the width and/ or thickness of the elongate magnets used in the panel means assembly.

It is believed that a novel and improved window, door assembly or the like has been provided and that the movement of these doors, or panels is made much easier than prior types of door or window constructions. The repelling or lifting magnetic forces provided can be adjusted by control of the size, type and number of magnets used to secure the desired floating or lifting action for the supported member dependent upon the weight thereof. Use of a repelling action between the poles is preferred, and the supported member is retained against movement out of vertical alignment with its positioning frame. The assemblies of the invention will give a long service life With a minimum or no maintenance thereon so that the objects of the invention have been achieved,

While several complete embodiments of the invention have been disclosed herein, it will be appreciated that modification of these particular embodiments of the invention may be resorted to without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. In the assembly of a vertically positioned, horizontally sliding door, window, panel or the like, the combination of frame means defining a vertical plane and having an opening therein,

a panel means slidably engaging said frame means for only horizontal movement, and limited vertical coacting guide means at the adjacent upper and lower margins of the said frame means and panel, and

elongate permanent magnet means operatively secured to said frame means and said panel means at adjapanel means at the lower end thereof and extending the length thereof, and

a second permanently magnetized flexible strip having two elongate permanent poles provided at spaced upper portions thereof corresponding to the pole positions of said first strip carried by said bottom member at an upper portion thereof and extending at least the length of the open center of said frame means,

cent vertically opposed portions thereof with the i 10 said strips being at least substantially of the same size magnet means on said panel means being above the and being in vertical alignment and havingvat least magnet means on said frame means, said magnet one pair of like poles therein immediately adjacent means being immediately adjacent in superimposed to provide a repelling action therebetween and a relation and having longitudinally extending poles lifting action on said panel means.

extending the lengths thereof, said magnet means 4. In the assembly of claim 3 where a plurality of said first strips are carried by said panel means in horizontally aligned and spaced parallel relation and a plurality of said second strips are carried by said bottom member in simion said frame means extending at least substantially the length of said opening and said magnet means on said panel means extending substantially the length thereof and said magnet means all having like poles thereof in adjacent spaced vertical positions to provide a repelling action therebetween to thereby provide a lifting action on said panel means to float said panel with relation to said frame means along its full length of slidable relation therewith.

ly opposed to and adjacent like poles of said first strips. 5. In the assembly of a vertically positioned sliding door, window, panel, or the like, the combination of frame means including at least a side, top and bottom members defining an opening,

2. In the assembly of a vertically positioned, horizona panel means slidably positioned in said frame means tally siding door, window, panel or the like, the combinafor relative horizontal movement therebetween and tion of movable in said frame means from an open to a frame means defining a vertical plane and having an closed position in said opening,

opening therein, coacting non-magnetic vertically extending guide means a panel means positioned by and slidably engaging said at the adjacent upper and lower margins of the same frame means and panel,

first permanently magnetized flexible strip having elongate permanent poles provided at spaced portions thereof and extending the length thereof carried by said panel means on said guide means adjaframe means for horizontal movement in the opening thereof, a coacting guide means at the adjacent upper and lower margins of the said frame means and panel, individual elongate permanent magnets operatively secured to each of said frame means and said panel means at adjacent vertically opposed portions there of with the magnets on said panel means being above a the magnets on said frame means, said magnets being ing the length thereof, and second permanently magnetized flexible strip having elongate permanent poles provided at spaced porlar relation with poles of said second strips being vertical-.

cent the lower end of said panel means and extendimmediately adjacent in superimposed relation and {ions thereof and extfindihg the length thereof having longitudinally extending poles extending the resp n in Position and Stffihgth t0 the Poles of lengths thereof, said magnets respectively extending Said first strip carried by said bottom member at an at least substantially the length of said opening and upper portion thereof, Said Second Strip extending at the length of said panel means and having like poles least Substantially the length of movemfiht Provided thereof in adjacent vertical positions to provide a said Panel means from p to Closfid Positions, repelling action therebetween to thereby rovide a said strips being in closely spaced vertical alignment lifting action on said panel means to float said panel and having least one P of like P0165 therein in with relation to said frame means, immediately adjacent opposed relation to provide said frame means including a top m mber h i supa repelling action therebetween and a lifting action port shelves thereon with a slot therebetween, on said Panel meanssaid panel means includes a top rail slidably engaging said frame means for relative horizontal and limited vertical movement therebetween, said top rail including a T-shaped section a portion of which extends up into said top member between said slot therein to be positioned above and adjacent said shelves,

at first said magnet being carried by said top rail by said T-shaped section on the lower surface of the upper end thereof, and

a second said magnet is carried by at least one of said shelves of said top member on the upper surface being above corresponding strips on said frame means.

8. In the assembly of a vertically positioned, horizontally sliding door, window, panel or the like, the combinathereof in opposed relation to said first magnet. tion of t 3. In the assembly of a vertically positioned sliding frame {means k a vertical plane and having an door, window, panel, or the like, the combination of Opemng therem open-centered frame means including side, top and a first Panel means engaigmg siud frame means and bottom members, covering a portion of said opening,

a panel means slidably positioned in said frame means a Second panel means Shdably en-gagmg Said frame for only relative horizontal and limited vertical means for ponzontal movement m this vemcal plane movement therebetween and movable in said frame sal'd seFond pa'nel means bemg Operativfily i positioned in said opemng and being movable from means fmm an p to aclhsed P F a position closing the remainder of said opening to 8. first permanently magnetized flexible SiIlp having a position exposing a part of aid opening and two elongate permanent poles provided at spaced elongate magnet means operatively secured to said lower portions thereof operatively carried by said 7 frame means and said second panel means at adja- 6. An assembly as defined in claim 5 characterized by said frame means, the said strips on said panel meansv cent vertically opposed portions thereof with the magnet means on said second panel means being above the magnet means on said frame means, said magnet means being immediately adjacent in superimposed relation and having longitudinally extending poles extending the lengths thereof, said magnet means on said frame means extending at least substantially the length of said opening and said magnet means on said second panel means extending substantially the length thereof and said magnet means all having like poles thereof in adjacent spaced vertical positions to provide a repelling action therebetween to thereby provide a lifting action on said second panel means to float said second panel means with relation to said frame means along its full length of slidable relation therewith.

References Cited DAVID I WILLIAMOWSKY, Primary Examiner. KENNETH DOWNEY, Examiner.

Claims

1. IN THE ASSEMBLY OF A VERTICALLY POSITIONED, HORIZONTALLY SLIDING DOOR, WINDOW, PANEL OR THE LIKE, THE COMBINATION OF FRAME MEANS DEFINING A VERTICAL PLANE AND HAVING AN OPENING THEREIN, A PANEL MEANS SLIDABLY ENGAGING SAID FRAME MEANS FOR ONLY HORIZONTAL MOVEMENT, AND LIMITED VERTICAL MOVEMENT, IN THE VERTICAL PLANE THEREOF, SAID PANEL MEANS BEING OPERATIVELY POSITIONED IN SAID OPENING AND BEING MOVABLE FROM A POSITION CLOSING AT LEAST A PART OF SAID OPENING TO A POSITION WHICH DOES NOT COVER AT LEAST SUCH PART OF SAID OPENING, COACTING GUIDE MEANS AT THE ADJACENT UPPER AND LOWER MARGINS OF THE SAID FRAME MEANS AND PANEL, AND ELONGATE PERMANENT MAGNET MEANS OPERATIVELY SECURED TO SAID FRAME MEANS AND SAID PANEL MEANS AT ADJACENT VERTICALLY OPPOSED PORTIONS THEREOF WITH THE MAGNET MEANS ON SAID PANEL MEANS BEING ABOVE THE MAGNET MEANS ON SAID FRAME MEANS, SAID MAGNET MEANS BEING IMMEDIATELY ADJACENT IN SUPERIMPOSED RELATION AND HAVING LONGITUDINALLY EXTENDING POLES EXTENDING THE LENGTHS THEREOF, SAID MAGNET MEANS ON SAID FRAME MEANS EXTENDING AT LEAST SUBSTANTIALLY THE LENGTH OF SAID OPENING AND SAID MAGNET MEANS ON SAID PANEL MEANS EXTENDING SUBSTANTIALLY THE LENGTH THEREOF AND SAID MAGNET MEANS ALL HAVING LIKE POLES THEREOF IN ADJACENT SPACED VERTICAL POSITIONS TO PROVIDE A REPELLING ACTION THEREBETWEEN TO THEREBY PROVIDE A LIFTING ACTION ON SAID PANEL MEANS TO FLOAT SAID PANEL WITH RELATION TO SAID FRAME MEANS ALONG ITS FULL LENGTH OF SLIDABLE RELATION THEREWITH.