US3451707A

US3451707A - Magnetic latch assembly

Info

Publication number: US3451707A
Authority: US
Inventors: John K Barry
Original assignee: Southco Inc
Current assignee: Southco Inc
Priority date: 1967-04-20
Filing date: 1967-04-20
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24

Description

June 24, 1969 J. K. BARRY'- 3,451,707

l MAGNETIC LATCH ASSEMBLY Filed April 20, 1967 IO 3| l 227 32 J is Si 25 y -5 Il F/'g INVENTOR. 3| 24 226 JOHN KBARRY l' .5 Fig 4 /g p Pf? g ATTORNEYS.

United States Patent O U.S. Cl. 292-251.5 3 Claims ABSTRACT OF THE DISCLOSURE The magnetic latch assembly has its magnet and pole plates enclosed in a rectangular housing of resilient plastic material, and retained therein by a rivet or stud. The for- Ward wall of the housing is of enlarged area, forming flanged portions for abutting against the door frame or panel. Opposite walls of the housing are provided with slots which extend which the front wall rearwardly, forming deformable outer ribs which are thicker at an intermediate point than at the forward and rearward portions. When the resilient plastic housing is pressed into the aperture in the door frame or panel, the ribs of the housing are deformed inwardly for the rst portion of the insertion and then snap outwardly during the latter portion Idue to the resilience of the material. 'Ihe plastic housing preferably includes, as an integral part of the molded housing, a couple of break-olf tabs. After the housing has been fully inserted into the door frame aperture, the 'breakaway tabs are pressed into the slots to maintain and fortify the outward thrust of the ribs.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to magnetic door holders or catches.

Description of the prior art A search of the prior art uncovered many patents directed to catches, latches and door holders of the magnetic type. The prior art patents most nearly related to the magnetic latch assembly of the present application are Martin, Jr. 2,896,991, Loeb 2,935,353, Ahlgren 3,057,650 and Heppner 3,276,804.

SUMMARY OF THE INVENTION The magnetic catch of the present invention is designed for holding a door which overlaps the door frame. Both the door and the frame may be assumed to be of sheet steel. The magnet and pole plates are contained in a resilient plastic housing, held therein by a rivet or stud. The front wall of the housing is flan-ged. Opposite walls, preferably the end walls, are each provided with a slot which extends, in the preferred embodiment, from the flanged front wall rearwardly toward the rear wall, forming an outer rib at each end. The rib is thicker at a point rearward of the forward wall and less thick at the forward and rear walls. When the resilient plastic housing is pressed into the aperture in the door frame, the ribs are cammed inwardly for the first portion of the insertion and spring outwardly during the last portion. The outward thrust of the ribs then maintains the flanged front wall against the door frame, thereby maintaining the housing in position.

In a preferred embodiment, lafter the housing has been pressed through the aperture in the door frame, plastic tabs are inserted into the slots which separate the ribs from the end walls. The insertion of these tabs maintains and fortifies the outward thrust of the ribs. The tabs are preferably molded as an integral part of the plastic housin-g, and may preferably be connected to a wall of the main housing by a reduced section or neck to facilitate Patented .lune 24, 1969 lbreaking off the tabs incident to their insertion into the slots.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a perspective illustration of a preferred em- Kbodiment of the magnetic latch assembly. In FIG. 1, the latch assembly is illustrated as installed in a door panel which is partially cut away to reveal the latch housing. FIG. 1 includes an indication of one way in which the reinforcing tabs may Ibe inserted into the slots, i.e., through the forward wall;

FIG. 2 4is an elevational side view of the magnetic latch assembly prior to installation;

FIG. 3 is an elevational side view in section of the installed magnetic latch assembly of FIG. 1;

FIG. 4 is a plan view looking down along the line IV-IV of FIG. 3;

FIG. 5 shows in section a portion of the magnetic latch assembly and illustrates how the rib is compressed inwardly during installation; and

FIG. 6 is a perspective view of a modified form of magnetic latch assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS bly 10 and a housing 20. The magnet assembly 10 includes a magnet 11, preferably a flat rectangular plate of permanent magnetic material, sandwiched between two flat rectangular

steel pole plates

12 and 13 which project forwardly from the magnet 11 when assembled. The magnet 11 and

pole plates

12 and 13 are provided with generally centrally located holes for receiving a rivet or stud.

The magnet assembly 10 is contained within the rectangular pocket 21 of a molded housing 20 which is formed of resilient plastic material, preferably high-density polyethylene. The pocket 21 of housing 20 is slightly larger in its cross-sectional dimensions than the magnet assembly 10 to allow the magnet assembly 10 to pivot, to a limited extent, about the rivet or stud 14, to allow the

pole pieces

12 and 13 to align themselves so as to be in full abutment with the surface of the door which is to be hel-d.

The magnetic latch assembly may be mounted in vertical, or horizontal, or any suitable angular position. In most instances, however, it will be mounted in a vertical position, as is illustrated in the drawing.

The novelty of the present invention resides primarily in the housing 20 which, in the preferred embodiment, comprises a flanged front wall 22, a rear wall 23, a pair of

side walls

24 and 25, and a pair of end walls slotted at 126 and 127. The

slots

126 and 127 .are illustrated as extending rearwardly from the front wall 22 almost, but not all the way, to the rear wall 23. The slots, which may preferably be slightly wider at the forward end, as seen in the cross-sectional views of FIGS. 2 and 3, form deformable

rib portions

26 and 27 outwardly of the slots. The portions of the end walls inward of the slots are identified as 226 and 227, respectively.

Where the body of the housing is accessible for insertion of the

tabs

31 and 32 into the side of the slots after the housing has been inserted into the door frame or panel aperture, the

slots

126 and 127 may terminate short of the front wall. In the preferred embodiment illustrated in FIGS. 1-5, the

slots

126 and 127 open into the front wall and at their `forward ends are completely surrounded by the flange portions of the front wall 22. In`a modified form, illustrated in FIG. 6, the slots 1261 and 127' open into the front wall 22 but the front wall is completely severed by the slots.

Referring again to FIGS. 1-5, it will be seen that the

ribs

26 and 27 of the end walls are not of uniform thickness. They are f minimum thickness at the front and rear walls, increasing progressively in thickness as they approach an intermediate point. In the drawing the

ribs

26 and 27 are shown as reaching maximum thickness at

points

26a and 27a located about one-quarter to one-third of the distance from the front toward the rear wall. Since the

peak points

26a and 27a are closer to the front wall 22 than to the rear wall 23, the slopes of the outer surfaces of the

ribs

26 and 27 are steeper between the front wall and the peak points than are the slopes from the peak points to the rear wall 23.

The manner in which the magnetic latch assembly is installed and the advantages derived therefrom will now be described.

In FIG. l, a door frame 40 is illustrated having a gasket 4'1 and a rectangular opening of a size and shape corresponding to that of the housing 20 at its rear wall. The height of the opening is, accordingly, less than the vertical distance between the

points

26a and 27a of the housing. When the housing is inserted into the opening, the rear wall 23 enters first, and as the housing is pressed rearwardly the

ribs

26 and 27 are subjected to compressive forces and as a result are deformed inwardly. This continues until the

peak points

26a and 27a are reached. This condition is illustrated in FIG. 5. As the inward movement of the housing continues, and the

peak points

26a and 27a are passed, the

ribs

26 and 27 return outwardly under their inherent resilient thrust, and the housing takes up the position shown in FIGS. l, 3 and 4 with the flanged front wall 22 abutting against the door frame 40.

Each time the door is opened, a forward pull is exerted on the magnetic latch assembly and an inward compressive force is applied to the

ribs

26 and 27 by opposite edges of the door-frame aperture. To aid the normal outward thrust of

ribs

26 and 27 to resist the compressive forces applied thereto,

plastic tabs

31 and 32 may be inserted into the

slots

126 and 127. Where the side openings of the slots are still accessible, the

tabs

31 and 32 may preferably be inserted into the slots 126 and `127 through the side, but in those cases where the body of the housing is not accessible, the

tabs

31 and 32 may be inserted into the slots through the openings in the front wall 22, in the manner indicated in FIG. 1.

Preferably, the

tabs

31 and 32 are molded as an integral part of the housing 20, at any convenient location thereon. In the illustrated embodiment, the tabs are shown extending rearwardly from the rear Wall 23. These tabs may preferably be connected to the rear wall 23 by a reduced or neck portion to facilitate breaking oif the tabs for insertion into the

slots

126 and 127. The

tabs

31 and 32 are shown as flat and smooth but may, of course, be ribbed and/ or take any suitable shape.

FIG. 6 illustrates a modification in which the

slots

126 and 127 completely sever the front wall 22 at its two ends. In other respects the latch assembly of FIG. 6 is similar to that shown in FIGS. 1-5. In the form shown in FIG. 6, when the housing is pressed through the opening in the door frame, the

ribs

26 and 27 are cammed inwardly, pivoting about the rear wall 23. When the

peak points

26a and 27a are reached and passed, the

ribs

26 and 27 spring outwardly to the extent allowed by the opening in the door frame. In the modified form shown in FIG. 6, the insertion of

tabs

31 and 32 into the

slots

126 and 127 is important, since the outward thrust of the ribs 26' and 27 is somewhat less than that of the form shown in FIGS. 1-5.

The preferred embodiments of my invention have been illustrated and described. Various modifications will occur to those skilled in the art.

What is claimed is:

1. A magnetic latch assembly comprising:

(a) a magnetic assembly comprising a permanent magnet and a pair of pole plates;

(b) a molded housing of resilient plastic material having therein a pocket sized and shaped to receive the magnet assembly;

(c) said housing having a forward wall, a rear wall, a pair of opposing side walls and a pair of lopposing end walls;

(d) at least one pair of opposing walls of said housing having slots therethrough forming exterior ribs adapted for inward movement in response to external compressive forces and outward return movement in response to the inherent thrust of the resilient material;

(e) said ribs having reduced thickness at their forward and rearward end portions and increased thickness at their intermediate portions;

(f) said plastic housing being molded with reinforcing tabs adapted to be removed for insertion into said slots after said housing has been pressed into position, for maintaining said ribs in their outward thrusted position;

2. A magnetic latch assembly comprising:

(a) a magnet assembly comprising a permanent magnet and a pair of pole plates;

(c) said housing having a forward wall, a rear wall, a pair of opposing side walls and a pair of opposing end walls;

(d) said pair of opposing end walls of said housing having slots therethrough forming exterior ribs adapted for inward movement in response to external compressive forces and outward return movement in response to the inherent thrust of the resilient material;

(f) the exterior surfaces of said ribs being inclined outwardly from their forward and rearward ends and reaching a peak at an intermediate point;

(g) said peak point being closer to said forward wall than to said rearward wall;

(h) said plastic housing being molded with reinforcing tabs adapted to be removed for insertion into said slots after said housing has been pressed into position, for maintaining said ribs in ltheir outward thrusted position.

3. A magnetic latch assembly comprising:

(a) a magnet assembly comprising a permanent magnet and a pair of pole plates;

(b) a molded housing of resilient plastic material having therein a pocket for receiving the magnet assembly;

(c) said housing being generally rectangular in shape and having a forward wall, a rear wall, a pair of opposing side walls and a pair of opposing end walls;

(d) said pair of opposing end walls of said housing having slots therethrough forming exterior ribs having a Width corresponding to the Width of said housing, said ribs being adapted for inward movement in response to external compressive forces and outward return movement in response to the inherent thrust of the resilient material;

(g) said peak point being closer to said forward wall than to said rearward wall.

UNITED References Cited 3,286,255 11/ 1966 Sanchez 3394-128 STATES PATENTS 3,351,368 11/1967 SWEC 292-2515 Sone 292 70 3,354,302 11/1967 Greasley 339-128 X LOeb 292--251.5 D` E Fraser n 3 3 9 128 5 RICHAR E. MOORE, Plzmary xammer. Ahlgren 292 251 5 E. J. MCCARTHY, Assistant Examiner. Hazelquist 329-128