US2609221A

US2609221A - Magnetic door catch

Info

Publication number: US2609221A
Authority: US
Inventors: Carl E Schultz
Original assignee: Laboratory Equipment Corp
Current assignee: Laboratory Equipment Corp
Priority date: 1949-08-06
Filing date: 1949-08-06
Publication date: 1952-09-02
Anticipated expiration: 1969-09-02

Description

Sept- 2, 1952 c. E. SCHULTZ 2,609,221

MAGNETIC DOOR CATCH Filed Aug. 6. .1949

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Patented Sept. 2, 1952 .UNITEoJisTATEs snrfeN'rgotsics y` v 2,609,221 V` j y `MAGNETIC Doon` Caron if v Carl E. Schultz, St. Joseph, Mich., assignor to Laboratory Equipment Corporation, St; Joseph, Mich., a corporation of Michigan H Application August 6, 1949, Serial No. 108,894'

1 Claim.

My invention relates to a magnetic door catch.

A magnetic doorcatch possesses several advantages for securing cabinet doors and the like which do not pertain to mechanical latches. A magnetic catch is incapable of mechanical malfunctioning. It may be small and unobtrusive and be installed with a minimum of effort, and a considerable'error in installation is permissible since the magnetic materials now known are capable of exerting the order of force required for retaining a cabinet door in the closed position over a considerable distance. A magnetic catch may be also relatively more noiseless than a mechanical latch since there need be nodirectfcontact between the latching elements, and by proper adjustment of such a catch a cabinet door may be retained in its closed position with any degree of force within the potentialities of the magnet employed. v l

One object of my invention therefore is to provide a novel magnetic door catch to which all the above stated yadvantages pertain.

Another object of my invention is to provide a magnetic door catch which is capable of relatively inaccurate installaton and which still provides scope for adjustment whereby the door to be latched by the catch may be held either in direct contact with the magnet for maximum retentive force or spaced somewhat away from the magnet to provide amore noiseless closing and an easier opening. p

Still another advantage of lmy invention is the provision of a novel magnetic latch which, while possessing the above advantages, is simply and easily formed, is decoratively attractive because of its simple structure, andvis unobtrusive in in stallation.

Still another advantage of my invention is the provision of a magnetic catch which is constructed in an entirely novel fashion so as to provide a magnetic retaining element which is smooth surfaced so as to minimize the catching of clothing or the breaking of, for example, pot tery as the cabinet is used and which is attractive in itself and suited for the provision of a decorative exterior.

Other objects and advantages of my invention will be apparent from the following description and drawings, in which:

Fig. 1 is a perspective view of a cabinet which includes one form of vmy magnetic catch, shown with door open;

Fig. 2 is a vertical section through the catch of the cabinet of Figure 1 with the door closed, taken parallel to the sides of the cabinet;

Fig. 3 is a` perspective view of the magnetic catch illustrated in Figs. 1 and 2; and p Fig. 4 is a perspective view of a modication of the catch illustrated in Fig. 3, V

The catch embodying my invention may be employed for any door retaining functiony but, for illustrativepurposes, is shown in the drawings as being mounted in a cabinet Ill to hold the door l2 thereof in closed position. The catch 8 may be mounted on any point 'of the cabinet spaced away from the hinged edge i4 of the door which faces the door opening. As shown,: it is mounted on the underside of the shelf i6 but may equally well be mounted on the side I8 of the cabinet or the top or bottom thereof.

The magnetic element 2li of my catch is a member of generally horseshoe shaped cross sec'- tion, the dimensions of which will of coursevary depending-'on'the desired magnetic force and the allowable bulk for the intended use. I have found, for cabinet closure purposes, that the dimensions of aboutone inch across the poles, onehalf inch from thepole surfaces to the back, and` three-quarters inch' depth afford sufficient strength and., at the same time, sufficient inconspicuousness for such use. This magnetic element in one modification of my invention may be encased in a block 22 of die casting metal or plastic resins or some similar substance which is suited to molding aboutsuch a magnet. The molding `is performed in such fashion that the faces 24 of the magnetic poles are exposed. This blockv is of a size sufiicient only to embed the magnetic element 20 rmly therein. On one edge of the block opposite the surface to which thev pole surfaces open is formeda mounting tab which is perforated with elongated slots 28 for the reception of such retaining means as screws or bolts 3i).

An illustrative example of the installation of the catch appears in the sectional view of Figure 2 wherein some portion of the cabinet such as the shelf l may be drilled to receive the bolts it at a distance properly spaced from the front edge of the shelf and the catch is then bolted `rmly through the holes 28 thereto. Because of the elongated mounting slots 28, it will be apparent that extreme accuracy in locating the catch retaining screws or bolts on the shelf is not imperative because the latch may be moved toward or away from the front edge to compensate for small inaccuracies.

In the event that the cabinet and more particularly the door thereof is made of wood, a metallic plate 32 may be secured to the dooras by a screw 34 with which the magnet will cooperate to hold the door rmly closed. In the event that the door is heavy, it will probably be desirable that the magnet 20 be positioned so that it may bear directly against the metallic door l2 or the metallic plate 32 on a wooden door since, obviously, maximum retentive force is obtained in this Way. However, this is subject to the disadvantage that the door Will click possibly somewhat noisily as` the plate 32 meets the magnet and therefore, particularly in the case of a lighter door, the magnet 20 may be backed slightly away from the surface of the plate 32 by virtue of the elongated slots 28 to prevent contact between these two metallic surfaces.

It is a characteristic of the presently used permanent magnet alloys, such as Alnico, that they are suiiciently hard as to be virtually nonmachineable. The only way in which a finished surface may be provided is by grinding, which is a time consuming and expensive operation. Herein lies the function of the encasing die casting metal or moldable plastic. By enclosing the magnet in these materials, a smooth surface is provided which is attractive in itself and which offers a smooth undersurface for other nishing techniques such aspainting, plating and the like. Encasing the magnet in this fashion offers a further advantage in that Alnico is of such hardness that it will scratch glass. By therefore enclosing it as I have done, the likelihood of injury to glassware or china through accidental contact is greatly reduced. This advantage pertains particularly to the plastic coating which will not only prevent the scratching, but by providing a relatively soft surface will also minimize breakage through such accidental contacts. A further advantage of this type of construction is that it lends itself tothe manufacture of a lower cost as Well as a better article. Preferably the U-shaped magnetic piece which is embedded in the molded material is formedby casting a long U-shaped rail and then subsequently sawing this rail with an abrasive saw into pieces of the desired size. These pieces are then encased in the molded material and finally the magnetic material piece is charged after the conclusion of the molding operation.

Where desired, however, my invention contemplates an alternative and somewhat simple although more expensive structure which is illustrated in Fig. 4. In this case the mounting tab 26 is formed integrally with the magnet 20 on the back side V36 of the magnet opposite the pole surfaces 24. This catch will similarly be furnished with the elongated mounting hole 28 whereby adjustment may be made for inaccuracies in mounting and for the desired placement of the pole surfaces 24 with respect to the metal of the door or of the plate 32. I'his embodiment'l of the invention is more expensive excepting perhaps in exceedingly small production lots because the excess magnetic alloy used for forming the mounting tab will cost more than the molding alloy or plastic material and further because the pieces probably will need to be individually cast rather than being formed as a rail which subsequently can be sawed into individual magnetic pieces. Also, of course, the device when so made will be, in general, less satisfactory for the reasons given in connection with the explanation of the earlier described form of the invention.

It will thus be apparent from the foregoing description that my invention provides a magnetic latch which is simply constructed and attractive in appearance, which may be inexpensively made, and easily and even carelessly mounted and still, by virtue of its adjustable feature, operate efficiently, and which is proof against mechanical failure.

I claim: l

As an article of manufacture, a magnetic door catch which consistsof a U-shaped slug providing a pair of side-by-side fiat pole surfaces in the same plane, said pole surfaces being separated by a void, said slug being formed of a magnetic material inherently having a rough surface of poor machinability such as Alnico, for instance, anda case for said slug formed of a moldable substance of the type affording the smooth and controllable surface characteristics of die cast metal, plastic resins, and the like, the case material lling the void between the poles and completely enclosing said slug excepting for the pole faces, said case having a mounting tab formed thereon at the end opposite said pole faces.

CARL E. SCHULTZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 451,603 Sterry May 5, 1891 2,152,897 Madore Apr. 4, 1939 2,209,809 Burton July 30, 1940 2,240,035 Catherall Apr. 29, 1941 2,277,057 Bach Mar. 24, 1942 2,446,336 Mark et al Aug. 3, 1948 2,489,154 Relton Nov. 22, 1949 2,519,367 Grunn et al Aug. 22, 1950 2,557,398 Teetor June 19, 1951