Magnetic catch

Nov. 29, 1960

2,962,318

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Μ. O. TEETOR

MAGNETIC CATCH

Filed Jan. 19, 1956

Sheets-Sheet 1

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Nov. 29, 1960 m. o. teetor 2,962,318

MAGNETIC CATCH

Filed Jan. 19, 1956 2 Sheets-Sheet 2

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United States Patent Office _{Palented Nov}²’⁹®²;³’³ showing a catch comprising one specific embodiment of the invention as mounted in one position thereof;

Fig. 2 is a view similar to Fig. 1 but showing a different mounting arrangement for the catch;

Fig. 3 is an end elevational view on an enlarged scale as seen along the line 3—3 of Fig. 2;

Fig. 4 is a sectional view taken along the line 4—4 of Fig. 3;

Fig. 5 is a sectional view taken along the line 5—5 of 10 Fig. 4;

Fig. 6 is a plan view of a blank or stamping from which the housing of the catch is formed;

Fig. 7 is a perspective view of the partially formed catch housing;

Fig. 8 is a fragmentary front elevational view of a cabinet provided with a catch comprising a second embodiment of the invention;

Fig. 9 is a large scale perspective view of the magnet assembly contained in the catch shown in Fig. 8;

Fig. 10 is an enlarged front elevational view of the complete magnet unit shown in Fig. 8;

Fig. 11 is a longitudinal sectional view taken along the line 11—11 of Fig. 10;

Fig. 12 is a transverse sectional view taken along the 25 line 12—12 of Fig. 10;

Fig. 13 is a top plan view of a magnet assembly comprising another embodiment of the invention;

Fig. 14 is an end elevational view of the device shown in Fig. 13;

³⁰ Fig. 15 is a sectional view taken along the line 15—15 of Fig. 13; and

Fig. 16 is a sectional view similar to Fig. 15 but showing still another embodiment of the invention.

Referring first to Figs. 1-7, this embodiment of the ³³ invention comprises a two-way or dual acting magnet unit adapted to be mounted in several different ways. For example, in Fig. 1 the magnet unit designated generally at 20 is secured to the underside of a cabinet shelf 21 for coaction with an armature unit in the form of a steel ⁴⁰ plate 22 secured by a screw 23 to the cabinet door designated at 24. In Fig. 2, the magnet unit 20 is secured to the inner edge of the door frame designated at 26 and the armature plate 22 is mounted in coacting relation at the inner face of the door 24.

⁴⁵ The magnet unit 20 comprises a non-magnetic housing with a permanent magnet assembly loosely retained therein for limited movement. For simplicity and economy, the housing is preferably formed from a one-piece sheet metal stamping or blank, e.g. brass or aluminum, as ⁵⁰ shown at 27 in Fig. 6. The blank 27 is folded along the dotted lines shown in Fig. 6 to provide a generally rectangular open-ended magnet-receiving recess defined by a front wall 28, a rear wall 29 formed from the butted edges of the folded blank, and a pair of side walls 31.

⁵⁵ Within the recess of the housing is mounted a generally rectangular permanent magnet assembly indicated generally at 32 and comprising a laminar structure including a relatively thin rectangular wafer or plate-like magnet element 33 and a pair of thin rectangular soft steel plates ⁶⁰ or pole pieces 34 at its opposite sides.

The magnet element 33 has a central bore or aperture 36, and the pole pieces are formed in this instance with inwardly extending depressed portions providing a pair of opposed integral bosses 37 extending into the opposite ⁶⁵ axial ends of the aperture 36 and coacting therewith for locating the magnet element and loosely retaining the same in assembled relation with the pole pieces. The entire magnet assembly 32 is loosely disposed in the rectangular recess of the housing for limited movement ⁷⁰ toward either of the open ends of the recess. Each pole piece 34 extends at its opposite edges beyond the cor, responding edge of the magnet element 33 to define a

2,962,318 MAGNETIC CATCH

Macy O. Teetor, 24 Orpheum Ave., Metaire, La.

Filed Jan. 19,1956, Ser. No. 560,176

Claims. (Cl. 292—251.5)

This invention relates to improvements in magnetic catches for cabinet doors and the like and more particularly 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 movable mounting of one of the catch elements, i.e. either the magnetic element or the armature element, and also the use of a spring operatively coacting 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 movable 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 for and has been specially designed to utilize a sintered ceramic magnet material such as the composite of barium and iron oxides available commercially under the trademark Indox. Magnet materials of this type have important advantages over metallic alloy magnets for many applications of permanent magnets such as in magnetic catches. For example, Indox magnets are lighter in weight than metallic alloy magnets, have certain superior magnetic characteristics including high coercive force, are easily magnetized but difficult to demagnetize, and are made from readily available non-critical raw materials, namely, barium carbonate and iron oxide. Moreover, the catch of the present invention is comparatively inexpensive but at the same time has extremely good holding power and is simple to manufacture and install.

Accordingly, a primary object of the present invention is to provide a novel and improved magnet assembly for use in magnetic catches.

A further object of the invention is to provide a novel and 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 specially 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

2,962, pair of elongated edgewise grooves 38 therebetween, and a pair of elongated bar springs 39 of non-magnetic spring material are disposed in these grooves 38 for resilient coaction with the magnet element 33. A pair of integral retaining ears or lugs 41 are provided at each open end 5 of the housing recess extending inwardly from the side walls 31 and engaging the end portions of the springs 39 thereby loosely retaining the entire magnet assembly in the housing.

As will readily be understood from Fig. 7, in assem- 10 bling the magnet unit 20 one pair of ears 41 may first be bent inwardly, followed by successive endwise insertion in the recess of one of the springs 39, the magnet assembly 32, and the other spring 39, and finally the remaining pair of ears 41 are bent over to complete the 15 operation.

As best seen in Fig. 7, the ears 41 are spaced by notches 42 from the adjacent front and rear walls 28 and 29 so that the projecting edge portions of the pole pieces 34 may extend beyond the ears 41 and the open ends of the 20 recess for magnetically contacting the armature element 22 in either of the mounting arrangements shown in Figs. 1 and 2. Thus, as shown in Fig. 4, when the door 24 is in closed position adjacent the frame 26, the right-hand projecting edges of the pole pieces 34 are drawn into 25 magnetic holding contact with the armature 22 so that the entire magnet assembly 32 is shifted toward the door thereby flexing the right-hand bar spring 39 outwardly. As a result the door 24 is held in closed position solely by the resilient inward retracting effect of the spring 39 ³⁰in the same general manner described in my aforementioned prior Patents Nos. 2,508,305 and 2,690,348. By reason of the slightly loose mounting of the magnet assembly 32 within the housing recess, as is evident from the clearance shown in Figs. 4 and 5, it will be under- ³⁵stood that the magnet assembly can undergo limited angular or cocking movement in order to align the contact faces of the pole pieces 34 with the armature 22 and thereby compensate for any slight misalignment between the door and frame members due to warpage or ⁴θ other causes. To facilitate such rocking self alignment of the magnet assembly, the opposite recessed longitudinal edges of the magnet element 33 which are engaged by the springs 39 have an outwardly bulged or generally convex curvature, as at 43 (Fig. 4). As will readily be 45 apparent, the curved edges 43 also allow the springs 39 to bend or flex as shown in Fig. 4 so as to permit outward movement of the magnet element for a predetermined distance.

As also seen in Fig. 4, the armature element 22 is 50 preferably an elongated rectangular steel plate having a single central aperture 44 which receives in countersunk relation the head of the screw 23. A pair of barbs or points 45 are formed in the armature plate at opposite sides of the screw 23 to facilitate accurate and speedy 55 installation of the armature plate while using only a single screw.

Because of the unique magnetic characteristics of Indox, it is desirable that the magnet material be proportioned to provide a relatively large magnetic area and 60 a relatively short magnetic length. For this reason, the generally rectangular wafer-like configuration of the magnet element 33 is desirable and the element is preferably magnetized along an axis extending transversely or through the thickness of the wafer, i.e. in a vertical direc- 65 tion as the element 33 is viewed in Fig. 5. Consequently, the magnet element 33 has a relatively large magnetic cross-sectional area extending along the curved edges 43 and at the same time the pole-to-pole distance or the dimension of the magnet in the direction of its mag- 70 netized axis is relatively small.

As heretofore mentioned, the magnet unit 20 comprises a two-way or dual acting unit whereby the catch can be mounted for operation in a plurality of different positions as shown by way of illustration in Figs. 1 and 2. 76

318

Thus, the catch has a wide degree of utility and is adapted to meet varying installation requirements. The sheet material forming the butted rear wall 29 extends integrally beyond the magnet-receiving recess of the housing and is formed with a parallel off-set bend to provide a mounting flange 46 having a plurality of apertures 47 whereby the catch unit is rigidly mountable by screws 48 on the door frame or other supporting structure. As previously mentioned, in the Fig. 1 installation, the movable magnet assembly 32 moves toward one of the open ends of the housing recess to contact the armature 22, and in the Fig. 2 installation the magnet assembly 32 moves toward the opposite open end of the housing recess in order to contact the armature 22. However, in each case one or the other of the spring members 39 provides the desired resilient inward retracting action which is essential to proper non-rattling operation of the catch. Another advantage of the double spring arrangement is found in the shock-absorbing action when the catch is released. For example, in Fig. 4, when the door 24 is opened the ^;magnetic contact between the pole pieces 34 and the armature 22 is disrupted whereupon the tensioned spring member 39 (at the right-hand side as viewed in Fig. 4) causes rapid resilient retraction of the magnet assembly within the housing. However, the left-hand spring member 39 cushions the inward movement of the magnet assembly thereby avoiding noisy and objectionable impact which is sometimes encountered in magnetic door catches.

Because of the somewhat limited impact resistance of magentic materials of the sintered ceramic type such as Indox, it is important to provide means for protecting the magnet material against severe impact such as might be encountered when a cabinet door is slammed. In the present embodiment of the invention, I provide abutment means or locating projections designed to insure accurate positioning of the magnet unit relative to its supporting structure and the cooperating armature unit. Thus, the sheet material forming the wall 29 has another laterally offset integral extension 49 which functions as an end abutment in the installation arrangement shown in Fig. 1 thereby insuring a predetermined minimum spaced relation between the armature plate 22 on the door and the magnet assembly 32 within the housing. Thus, even if the door 24 is slammed with considerable force, the stop action of the abutment 49 prevents undesirable forceful impact of the armature 22 against the magnet assembly. In fact, the magnet assembly 32 must move outwardly against the action of one of the spring members 39 in order to complete magnetic contact with the armature 22.

For the Fig. 2 mounting arrangement, the mounting flange 46 is provided with an outwardly struck integral tang or abutment 51 which is adapted to engage the inner edge of the door frame 26, as best seen in Fig. 5, thereby insuring the desired spaced relation between the movable magnet assembly 32 and the armature plate 22 on the door. As seen in Fig. 6, the tang 51 is conveniently formed by providing partially sheared areas 52 in the J housing blank 27 which are adapted to abut in con- | tinuous edgewise relation to form the tank 51 when the housing is completely formed.

Referring now to Figs. 8 to 12, the invention is illustrated in connection with a single acting or one-way catch having a non-magnetic housing (in this instance plastic) which is generally similar to the housing shown in my prior Patent No. 2,690,348. Thus, in Fig. 8 the magnet unit, designated generally at 53, is mounted on the sill 54 of a cabinet frame, and an armature element in the form of an apertured washer 55 is rigidly mounted on the cabinet door 56 by means of a screw 57. The magnet housing has an elongated body portion 58 with a mounting flange having slots 59 for adjustable mounting of the unit by means of a pair of screws 60. The body 58 of the magnet housing has a centrally located socket portion 61 which in this instance is generally rectangular in shape. The movable magnet assembly (Fig. 9) com2.962.318 s

prises a waferlike element 63 of Indox or the like having a curved edge 64 and a pair of steel plates 66 providing pole pieces which project beyond the curved edge 64 of the magnet element to define a spring-receiving groove in the same general manner as heretofore described. This magnet assembly is held in assembled relation by means of a non-ferrous or non-magnetic tubular pin or bushing 67 which extends through an aperture 68 in the magnet element 63 and has its opposite end portions received in a pair of sockets or cavities 69 in the pole pieces 66. In the illustrated embodiment, the sockets 69 are formed by providing integral outwardly bulged portions 71 in the plates 66. The bushing 67 serves to locate the pole pieces 66 relative to the magnet element 63 and holds the parts in assembled relation.

As best seen in Figs. 10 and 12, this embodiment of the invention has particular utility in situations where it is desired to utilize existing magnetic catch housings with the relatively powerful and compact Indox magnet assemblies. With magnetic catches using magnetic alloy magnet elements such as Alnico, the size of the magnet unit has been appreciably larger and, therefore, the size of the recess 61 in the housing 58 is somewhat greater than is required for a small size Indox magnet assembly. However, by means of the oppositely extending rounded protuberances 71 at the opposite sides of the magnet assembly, a spacer or filler effect is realized so that the relatively smaller magnet assembly can effectively be used in the relatively larger size magnet housing. In other words, the projections 71 serve to fill the extra space within the recess 61 and locate the magnet assembly within the enlarged recess.

An elongated non-magnetic bar spring member 72 extends through the groove between the pole pieces 66 of the magnet assembly and the ends of the bar spring 72 are received within the interior of the housing 58 in abutment with a pair of shoulder portions 73. When the cabinet door is closed, the magnet assembly moves outwardly against the retracting action of the spring 72 to permit magnetic contact between the pole pieces 66 and the armature 53 as clearly seen in Figs. 11 and 12. Otherwise, the operation of the catch is generally similar to the previously described embodiment and also similar to the catch described in my prior Patent No. 2,690,348.

In Figs. 13, 14 and 15 a slightly different, embodiment of the magnet assembly is shown comprising a wafer-like magnet element 74 and companion pole pieces 76 provided with aligned apertures 77 and 78, respectively. In this case, a non-magnetic tubular bushing 79 extends through the aligned apertures 77 and 78 and the ends of. the bushing project beyond the pole pieces 76. A pair of plastic hemispherical caps 81 are tightly secured to the projecting ends of the tubular bushing 79 for holding the parts in assembled relation, the caps 81 having internal socket portions 82 for receiving the ends of the bushing 79. As will readily be understood, the caps 81 may be of any desired size in order to provide the required spacer or filler effect.

In Fig. 16 still another slight modification of the magnet assembly is shown comprising an apertured magnet element 83 and a pair of apertured pole pieces 84. In this instance the magnet element and the pole pieces are retained in assembled relation by means of a solid nonmagnetic pin 86 rather than a tubular pin or bushing as previously described. Also, in this instance, the external protuberances or spacer bumps have been omitted so that the magnet assembly may be utilized with the same type of housing shown in Figs. 1 to 7.

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