US2954253A - Magnetic catch - Google Patents

Description

SePt- 27, 1960 M. o. TEE-ron 2,954,253

MAGNETIC CATCH Filed May 7, 1957 .Patterned sept. 27, 1960 2,954,253 MAGNETIC CATCH Macy 0. Teetor, 24 Orpheum Ave., Metaire, La. Filed May 7, .1957, Ser. No. 657,580

13 Claims. (Cl. 292-2515) This invention relates to improvements in magnet-ic catches for cabinet doors and the like and more particul-arly to a novel permanent magnet assembly for use in such catches.

Magnetic door catches of various types have been suggested heretofore in which cooperating magnet and armature units are mounted in coacting positions on-door and frame members. In my prior Patents Nos. 2,508,305 and 2,690,348 I have shown one type of magnetic catch which is highly effective `and provides a number of important advantages over other magnetic and non-magnetic catches heretofore suggested. One of the principal features of my prior inventions involves the lmovable mounting of one of the catch elements, i.e. either the magnet element or the armature element, and also the use of a spring operatively ooacting with the movable catch element for normally urging it into retracted position inwardly of its supporting door or frame member.

The present invention is directed to an improved magnetic catch including a Imovable magnet assembly having a unique design which results in enhanced magnetic holding power and a highly effective catch operation. As will hereinafter appear, the catch of the present invention is particularly adapted vfor and has been specially designed to utilize a sintered ceramic magnet material such as the composite of barium and iron oxides available cornmercially under the trademark Indox. Magnet materials of this type have important advantages over metallic alloy magnets for many applications of permanent m-agnets such as Vin magnetic catches. For example, lndox magnets are lighter in weight than metallic alloy magnets, have certain superior magnetic characteristics including high coercive force, are' easily magnetized but difcult to demagnetize, and are made from readily available non-critical raw materials, namely, barium carbonate and iron oxide. Moreover, the catch of the present linvention is comparatively inexpensive but at the same time has extremely good holding power and is simple to manufacture and install.

Accordingly, a primary object ofthe present -invention is to provide a novel land improved magnet assembly for use in magnetic catches.

A further object of the invention is to provide a novel yand improved magnet unit for a magnetic catch utilizing the aforementioned magnet assembly.

Another object of the invention is to provide a novel permanent magnet assembly for a magnetic catch which is speci-ally adapted for utilization of a powerful sintered ceramic magnet material such as the composite of barium and iron oxides known commercially as'Indox.

An additional object of the invention is to provide a novel highly simplified, and inexpensive magnetic catch.

Other objects and advantages of the invention will become evident from the subsequent detailed description taken in conjunction with the accompanying drawings,

wherein:

Fig. 1 is a fragmentary sectional view of a cabinet showing a catch comprising one specific embodiment of the invention as mounted in one position thereof;

Fig. 2 is a View similar to Fig. l but showing the catch mounted on a slightly different cabinet structure;

Fig. 3 is a fragmentary sectionalview showing another method of mounting the catch;

Fig. 4 is a front elevational view of the armature unit as seen along the line 4 4- of Fig. 3;

Fig. 5 is an enlarged plan View of the magnet unit of the catch;

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 5; and

Fig. 7 is a sectional view taken along the line 7-7 of Fig. V5.

Referring first to Figs. l to 4 of the drawing, the illustrated embodiment of the invention comprises a magnetic catch unit which is adapted to be mounted on a cabinet structure in several different ways. For example, in Fig. 1 the -magnet unit of the catch, designated generally at 11, is secured to the inside of a cabinet door 12 of the flush type, and the coacting armature uni-t of the catch, designated generally at 13, is secured to the cabinet wall or frame portion 14. The armature unit 13 comprises in this instance an angle element of steel or other magnetic metal having one leg portion 16 adapted to lbe disposed for contact with the operating pole faces of the magnet unit, as hereinafter described in detail, and another leg portion 17 providing a mounting flange whereby the armature unit may be secured to the cabinet frame. In this instance, the fastening of the armature unit 13 is accomplished by means of a pair of spaced screws 18 (Fig. 4) and a small nail 19 therebetween. The screws 18 extend through slots (not shown) in the leg portion 17 so as -to permit. adjustment of the armature. In Fig. 2, the catch is illustrated as it might be installed on a cabinet lhaving a lip type door 21. The magnet unit 11 is mounted at the inside face of the door 21, and the armature unit 13 is secured to the inner edge of the adjacent cabinet frame, as at 22. In Figs. 3 and 4, a shelf type installation is sho-wn wherein the magnet unit 11 is again mounted at the inside face of a door 23 and the armature unit 13 is secured adjacent the front edge of a horizontal shelf 24, as best seen in Fig. 4. It ywill be evident that other types of installation may also be employed.

The magnet unit 11 comprises -a non-magnetic hous- A ing of aluminum, brass, plastic, or the like with a permanent magnet assembly contained therein for 'limited movement. As illustrated, the housing provides a generally rectangular magnet-receiving recess defined by an outermost front wall 26, oppositely disposed end walls 27, and oppositely disposed elongated side walls 28. The innermost or rear side of the housing is substantially open except yfor a pair of retaining tabs 29 (Figs. 6 and 7) which extend inwardly from the lower edges of the end walls 27 for the purpose described hereinafter. An integral mounting flange 31 extends outwardly from one of the side walls 28 and is provided with a plurality of openings 32 -for securing the magnet unit to the supporting structure, as by means of a pair of screws 33 in Figs. l, 2, and 3. The apertures 32 are preferably formed with sharp pointed tangs or barbs 34 struck from the edges thereof and adapted to penetrate into the supporting structure to facilitate mounting of the magnet unit.

Within the rectangular recess of the non-magnetic housing is disposed a generally rectangular permanent magnet assembly designated generally at 36 in Figs. 6 and 7. The magnet assembly comprises a laminar structure including a relatively lthin rectangular wafer or plate-like magnet element 37 and a pair of generally L-shaped pole elements in the form of thin rectangular soft steel plates having bent over or angularly extending end portions. As seen in Fig. 6, one such pole element has a flat plate portion 38 disposed against the upper at side of the magnet element 37 and the pole element is bent outwardly at right angles at its left-hand end to provide a leg 39 with a rounded pole face or edge at its outermost extremity. Similarly, the other pole element has a at plate portion 41 disposed against the lower side of the magnet element 37 and its right-hand end portion is bent outwardly at right angles to provide a leg 42 with a rounded pole face or edge at its outermost extremity. The front wall 26 of the magnet housing is formed with a pair of spaced transverse slots 43 through which the parallel legs 39 and 42 project for contacting the armature unit 13.

Thus, in the magnet housing the magnet element 37 is sandwiched between lthe plate portions 38 and 41 of the pole elements, and each pole element has one outwardly bent end portion so as to provide at the opposite ends of the magnet assembly 36 a pair of cooperating pole faces. As will readily be apparent, the outwardly bent leg portion 42 is longer than the leg portion 39 so that the pole faces at the outer extremities thereof are normally aligned in a single plane which is substantially parallel to the front wall 26 of the housing.

For retaining the magnet assembly 36 in assembled relation, the magnet element 37 is provided with a central aperture 43, and the plate portions 38 and 41 of the pole elements 38-39 and 41-4'2 are formed with inwardly extending depressed portions providing a pair of opposed integral bosses 44 and 46, respectively, which extend into the opposite axial ends of the aperture 43 and coact therewith for locating the magnet element 37 and retaining the same in assembled relation with the pole elements. The entire magnet assembly 36 is loosely disposed in the rectangular recess of the housing for limited movement therein. Normally, the magnet assembly 36 is retained in retracted position with the plate portion 41 abutting the retainer tabs 29 (as shown in full lines in Fig; 6) by the action of a resilient device such as an elongated strip of nonmagnetic spring material 47. In the illustrated embodiment of the invention the spring 47 has a normally bowed contour with an integral protuberance or indentation 48 at its center portion which is received in .the depressed boss portion 44 of the pole element 38-33. The opposite ends of the spring strip 47 engage the inside of the housing wall 26, and the spring is retained against endwise displacement by means of a pair of inturned flanges or shoulders 49 extending along the innermost edges of the slots 43.

As will readily be understood, the effective magnetic pole faces at the outer extremities of the legs 39 and 42 project through the slots 43 beyond the front wall 26 of the housing and are adapted to make magnetic Contact with the leg portion 16 of the armature unit 13 in the various mounted positions of the catch as illustrated in Figs. l to 4. When the cabinet door is open, it will be understood that the magnet assembly 36 is retained in its innermost retracted position as shown in full lines in Fig. 6 by the action of the spring 47. However, when the cabinet door is in closed position, the magnet assembly shifts outwardly against the action of the spring 47 until the pole faces at the outer ends of the legs 39 and 42 make magnetic contact with the armature unit. For most elective operation of the catch and for realizing the optimum benefit of the spring 47 in accordance with the principle described in my aforementioned prior Patents Nos. 2,568,305 and 2,690,348, it is desirable that a predetermined spacing (not shown) be provided between the magnet unit 11 and the armature unit 13 when the door is in closed position, this spacing being such that the magnet assembly 36 must move outwardly against the action of the spring 47 to contact the armature unit 13 so that the door is held in closed position solely by the resil-ient retracting eect of the exed spring 47. By reason of the relatively loose mounting of the magnet assembly 36 within the housing recess, and particularly by reason of the clearance between the legs 39 and 42 and the respective slots 43, it will be seen that the magnet assembly 36 can undergo limited angular or cooking movement in order to align the pole faces of the leg portions 39 and 42 with the armature leg 16 and thereby compensate for slight misalignment between the door and frame members due to warpage or other causes.

Because of the unique magnetic characteristics of lndox and other sintered ceramic magnet materials, it is desirable that the magnet element be proportioned to provide a relatively large magnetic area and a relatively short magnetic length. For this reason, the generally rectangular wafer-like configuration of the magnet element 37 is highly advantageous and the element is preferably magnetized along an axis extending transversely through the thickness of the wafer, i.e. in a vertical direction as the element 37 is viewed in Fig. 6.. Consequently, the magnet element 37 has a relatively large magnetic cross-sectional area and at the same time the pole-to-pole distance or the dimension of the magnet element in the direction of its maguetized axis is relatively small. By utilizing the L-shaped pole elements 38-39 and 41-42, the effective pole faces of the magnet assembly are disposed in a plane parallel to the plane of the magnet element 37 thereby providing a highly compact, inexpensive, and convenient arrangement for making use of the powerful magnetic characteristics of this type of magnet material.

Although in the installations of the catch unit illustrated in Figs. l to 4 the magnet unit is shown mounted on the door and the armature unit is mounted on the frame or shelf of the cabinet, it is also within the scope of the invention to reverse the respective mounting positions so that the magnet unit is' secured to the frame or shelf structure and the armature unit is mounted on the door.

The operation of the catch will be readily apparent from the foregoing description and may be summarized briefly as follows. When the door is open, the magnet assembly 36 is retained in the retracted full line position of Fig. 6 by the action of the spring 47 holding the magnet assembly against the retaining tabs 29. As the door is moved toward closed position, the pole faces of the leg portions 39 and '42 of the magnet assembly are eventually attracted to the leg 16 of Ithe armature unit 13 and the magnet assembly 36 moves outwardly relative to the housing and against the action of the spring member 47 until magnetic contact is established with the armature unit. Because of the somewhat limited impact resistance of magnetic materials of the sintered ceramic type such as Indox, it is important to protect the magnet material against severe impact such as might be encountered when a cabinet door is slammed. In the present invention this is accomplished by properly mounting the armature unit 13 on the frame or shelf or other supporting structure so that when the cabinet door is in its fully closed position in abutment with the usual frame or stop member (not shown), a predetermined minimum spaced relation will exist between the magnet and armature units so that the magnet assembly 36 must move outwardly relative to the magnet housing in order to establish contact with the armature unit. This arrangement results not only in protection of the magnet element against severe impact, but also causes the door to be held in closed position solely by the resilient effect of the partially compressed spring |47 as heretofore mentioned. This arrangement insures non-rattling retention of the cabinet door in closed position and at the same time provides for an effective degree of resilient selfadjustment of the magnet assembly to compensate for slight misalignment between the magnet and armature units due to warpage, improper installation, and other causes. During opening of the cabinet door the magnet assembly 36, although being urged inwardly of the housing by the spring 47, can move outwardly to the position shown in broken lines in Fig. 6 with the plate vportion 38 in contact with the inner edges of the llanges 449. Continued opening movement of the door will Vresult in disruption of the magnetic contact and attraction between the poile faces of the magnet assembly and the armature unit, the rigid metal-to-metal contact between the plate portion 38 and the ilanges 49 providing the necessary breaker action. Immediately yupon disruption of the magnetic contact, the magnet assembly 36 will be restored to its retracted full line position, as seen in Fig. 6, by the action of the spring 47.

Although the invention has been described with particular reference to a certain specic structural embodiment thereof, it is to be understood that various modiiications and equivalent structures may be resorted t0 without departing from the scope of the invention as defined in the appended claims.

I claim:

l. For use in a magnetic catch including a non-magnetic housing adapted to be mounted rigidly on a supporting structure, a permanent magnet assembly adapted t0 be movably contained in the housing for coaction with an armature unit, said assembly comprising a plate-like magnet element and a pair of generally L-shaped pole elements each having a flat plate portion and a laterally extending leg portion at one end of the plate portion, the plate portions of said pole elements being disposed in laminar relation at opposite sides of said magnet element and the leg portions of said pole elements being disposed at opposite ends of said assembly and providing pole faces at their outer ends in cop'lanar relation for contacting the armature unit.

2. For use in a magnetic catch including a non-magnetic housing adapted to be mounted rigidly on a supporting structure, a permanent magnet assembly adapted to be movably contained in the housing for coaction with an yarmature unit, said assembly comprising a plate-like magnet element, a pair of generally L-shaped pole elements each having a flat plate portion and a laterally extending leg portion Vat 'one end of the plate portion, the plate portions of said pole elementsrbeing disposed in laminar relation at opposite sides of said magnet element and the leg portions of said pole elements being disposed at opposite ends of said assembly and providing pole faces at their outer ends in coplanar relation for contacting the armature unit, said pole elements having portions coacting with said magnet element for locating said pole elements on said magnet element in said laminar relation.

3. For use in a magnetic catch including a non-magnetic housing adapted to be mounted rigidly on a supporting structure, a permanent magnet assembly adapted to be movably contained in the housing for coaction with an armature unit, said assembly comprising a plate-like magnet element having an aperture therethrough, a pair of generally L-shaped pole elements each having a at plate portion and a laterally extending portion at one end of the plate portion, the plate portions of said pole elements being disposed in laminar relation at opposite sides of said magnet element and the laterally extending portions of said pole elements being disposed at opposite ends of said assembly and providing pole faces at their outer ends in coplanar relation for contacting the armature unit, said pole elements each having a portion extending transversely toward the plate portion of the opposite pole element in said aperture.

4. For use in a magnetic catch including a non-magnetic housing adapted to be mounted rigidly on a supporting structure, a permanent magnet assembly adapted to be movably contained in the housing for coaction with an armature unit, said assembly comprising a platelike magnet element having an aperture therethrough, a pair of generally L-shaped pole elements each having a flat plate portion and a laterally extending portion at one end of the plate portion, the plate portions of said pole elements being disposed in laminar relation at 0pposite ksides of said magnet lelement `and the laterally extending portions of said pole elements being disposed at opposite ends of said assembly and providing pole faces at their outer ends in coplanar relation for contacting the armature unit, each of `said pole elements having a portion projecting inwardly therefrom into said aperture atthe opposite axial ends thereof.

5. For use in a magnetic catch including a non-magnetic housing ladapted to be mounted rigidly on a supporting structure, a permanent magnet assembly adapted to be movably contained in the housing for coaction with an :armature unit, lsaid assembly comprising a plate-like magnet element having lan aperture therethrough, and a pair of generally L-shaped pole elements each having a ilat plate portion and a laterally extending portion at one end of the plate portion, the plate portions of saidpole elements ibeing .disposed in laminar relation at opposite sides ofsaid magnet element and the laterally extending portions of said pole elements being disposed at opposite ends of said assembly and providing pole faces at their outer ends in coplanar relation for contacting the armature unit, and the plate portions of said pole elements having inwardly depressed portions providing a pair of opposed integral bosses extending into the opposite ends of said aperture.

6. The magnet assembly of claim l lfurther characterized in that said magnet element comprises a generally rectangular wafer having its magnetized axis extending -through the thickness of the wafer whereby to provide a relatively large cross-sectional magnet `area with a relatively short magnet Ilength in the direction of said magnetized axis.

7. In a magnetic catch, a magnet unit mountable on one of a pair of door and frame members for coaction with an armature unit mounted on the other of said members, said magnet unit comprising a non-magnetic housing having a magnet-receiving recess and a wall with a pair of spaced openings therein, a magnet assembly disposed in said recess and comprising a plate-like magnet element and a pair of generally L-shaped pole elements, each of said poleelements having aat plate portion and a laterally extending leg portion at one end of -the plate portion, the plate portions of said pole elements being disposed in laminar relation :at opposite sides of said magnet element and the leg portions of said pole elements being disposed at opposite ends of said assembly and projecting through said openings in the housing wall whereby to provide pole faces at the outer extremities of said leg portions for contacting the armature unit, and means for retaining said magnet assembly in said housing but permitting limited movement thereof relative to the housing.

8. The magnet unit of claim 7 further characterized by the provision of resilient means coacting between said housing and said magnet assembly for normally urging the latter inwardly of the housing but permitting limited resilient outward movement of the magnet assembly for contacting the armature unit.

9. In a magnetic catch having -a magnet unit mountable on one of Ia pair of door and frame members for coaction with an armature unit mounted on the other of said members, the combination in said magnet unit of a magnet assembly adapted to be movably contained in a non-magnetic housing, said assembly comprising a platelike magnet element having an aperture therethrough and a pair of generally L-shaped pole elements each having a llat plate portion and a laterally extending leg por-tion at one end of the plate portion, the plate portions of said pole elements being disposed in laminar relation at opposite sides of said magnet element and the leg portions of said pole elements extending outwardly from opposite ends of said `assembly and providing pole faces at their outer ends for contacting the armature unit, the plate portions of said pole elements also having depressions therein providing a pair of opposed integral bosses extending into the opposite axial ends of said aperture for retaining the pole elements and the magnet element in assembled relation, and an elongated spring member having its end portions `disposed outwardly from the magnet assembly `and adapted to coact with the housing and having a protuberance intermediate the ends thereof extending into and engaging the depression in one of said pla-te portions for exerting resilient 4action against the magnet assembly.

10. In a magnetic catch, a magnet unit mountable on one of -a pair of door `and frame members for coaction with an armature unit mounted on the other of said members, said magnet unit comprising a non-magnetic housing having a generally rectangular magnet-receiving recess and having a wall with `a pair of spaced slots therein, a generally rectangular magnet assembly movably disposed in said recess, said magnet assembly including a plate-like magnet elem-ent having a pair of gene-rally L-shaped pole elements each having a flat plate portion and a laterally extending leg portion at one end of the plate portion, the plate portions of said pole elements being disposed in laminar relation at opposite sides of said magnet element and the leg portions of said pole elements extending outwardly through said slots at opposite ends ot the magnet assembly whereby to provide pole faces 'at the outer extremities of said leg pontions adapted to contact the arma ture unit, elongated spring means interposed between and engaging said wall and said magnet assembly tor normally urging the latter inwardly of the housing but permitting limited resilient outward movement of the magnet assembly relative to the housing, said spring means being disposed between said slots, and retainer means extending inwardly from said wall adjacent said slots for retaining the opposite ends of said spring means.

11. The magnet unit of claim l `further characterized in that said spring means comprises an elongated onepiece bowed spring element having its end portions in engagement with said wall and having an intermediate portion thereof engaging said magnet assembly, and said retainer means comprising inw-ardly bent iiange portions at the edges of said slots. l

12. In la magnetic catch, a magnet unit mounted on one of a pair of door and rframe members for coaction With an armature unit mounted on the other of said members, said magnet unit comprising a non-magnetic housing having coacting front, side, and end walls with an open r'ear portion and defining a generally rectangular magnetreceiving recess, said front wall having a pair of spaced transverse slots therein, a generally rectangular magnet assembly movably disposed in said recess and including pole pieces having outwardly extending leg portions projecting .through said slots whereby to provide pole Afaces adapted to contact the armature unit, said front wall of the housing having integral flange portions extending inwardly of the housing along the edges of said slots, an elongated spring element interposed in the space between said flanges Iand coacting between said iront wall and the magnet assembly for normally urging the latter inwardly into retracted position in said housing but permittitng limited resilient outward movement of the magnet assembly relative to the housing, the inner edges of said flanges being adapted to abut `the magnet assembly for limiting the extent of outward movement of the latter, and a pair of retainer tabs extending inwardly from oppositely disposed walls of -said housing at the open rear portion thereof for engaging lthe magnet assembly in its normal retracted position in said housing.

13. The magnet unit of claim 12 further characterized in that said housing is also provided with a mounting iiange extending laterally in parallel relation with said front wall and in generally the plane of `said open rear portion of the housing.

References Cited in the le of this patent UNITED STATES PATENTS 2,397,931 Ellis Apr. 9, 1946A 2,694,592 Borchers et al Nov. 16, 1954 2,770,759 Ahlgren Nov. 13, 1956 2,808,281 Poe Oct. 1, 1957 2,837,366 Loeb June 13, 1958 2,862,752 Heppner Dec. 2, 1958 FOREIGN PATENTS 544,110 Great Britain Mar. 27, 1942

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