US2896991A

US2896991A - Magnetic door holder

Info

Publication number: US2896991A
Authority: US
Inventors: Jr William C Martin
Original assignee: Magni Power Co
Current assignee: Magni Power Co
Priority date: 1956-07-17
Filing date: 1956-07-17
Publication date: 1959-07-28
Anticipated expiration: 1976-07-28

Description

July 28, 1959 w. c. MARTIN, JR

MAGNETIC DOOR HOLDER Filed July 17, 1956 Fig. 1

INVENTOR. WILLIAM c. MART/N, JR BY 6 9%! (ms! 9W ATTORNEYS Fig. 3

United States Ohio, assignor to Wooster, "Ohio, a corporation This invention relates to door holders and more particularly to an improved magnetic door holder for holding a door in a closed position.

In the past attempts have been made to construct door holder units which may be snapped into an aperture in a metal door frame for connection without the use of springs, screws or other connection means. Magnetic door holders for use with metal doors such as lavatory or cabinet doors are also well known. Attempts to combine the features of both of these holders, that is a magnetic door holder having the snap-in feature, have not proved successful.

When a magnetic door holder is used in a metal door it is generally necessary to provide an insulating nonmagnetic housing. This is true because the material used in constructing the door is generally a magnetic material which will bleed the power of the magnet unless insulation is interposed between the two. There are few nonmagnetic materials which have suitable inherent resiliency to permit successful employment as a snap-in housing if made in accordance with prior teaching. In known snap-in housings a lip is provided in side walls of the housing. The lip is yieldable inwardly as the housing is pressed through a panel aperture and the lip then springs outwardly after it has passed through the aperture.

Such a housing may successfully be made of certain types of non-magnetic stainless steel to serve as a housing for a magnetic door holder. However, the cost of such a stainless steel housing is prohibitive and there are certain other drawbacks as well.

It has been discovered that if a housing is constructed so that lips are integrally formed with the side walls and the housing is so constructed that both the lip and the side wall will be yieldable, a non-magnetic snap-in hous- ,ing can be constructed. A plastic material such aspolyvinyl acetate may be used in such construction. The

polyvinyl plastic has both the inherent resiliency and strength to serve excellently as a material for the snap- ,in nonrmagnetic holder housing.

Accordingly, one of the principal objects of this in- .vention is to provide a non-magnetic housing which may forma snap-in connection with a metal panel.

. A further object of this invention is to provide a uni-,

- tary.magnetic door holder which may simply be snapped 1 into an aperture in a metal panel as the entire assembly operation, an opposed metal panel being used as a striker plate. Thus, if the housing is snapped into an aperture 7 in a metal door panel, used as the striker plate.

the metal door frame may be An additional object of this invention is to provide Jan inexpensive, easily constructed, one-piece housing for a magnetic door holder which is open-ended to permit ready assembly of a compact unitary magnetic door holder.

Metal doors frequently become warped or are inaccu- I rately mounted so that there is misalignment between atent 28%,991 Patented July 28, 1959 magnets and pole pieces form a magnetic member which moves as a unit toward an opposed striker plate. In prior applications where a metal door has become Warped, frequently substantially one-half of the closing force of the holder has been lost because only one of the pole pieces strikes the opposing striker plate. This difficulty has been overcome by providing a projection which may take the form of a transversely extending rib which the magnet pulls against when the holder is in operation. The entire magnet member is relatively pivotal or rockable on this rib. Thus, the magnet member becomes self-aligning for warpage or other out-of-line conditions.

Thus, a further object of this invention is to provide a self-aligning magnet member which will provide full closing force even when bad misalignment conditions prevail.

Prior known pole pieces have generally been formed in the shape of a block letter T. The stem of the letter T projects through an aperture in the holder housing and the cross arm of the T forms shoulders to abut the housing and prevent the pole piece from being pulled from the housing. Pole pieces of this construction are difiicult and expensive to manufacture. The life of dies used to make such pieces is frequently short because of the sharp rectangular inside corners required at the cross of the T and because the metal from which they are stamped is frequently a magnetic stainless steel. It has been discovered that an improved pole piece may be constructed which is both far simpler and less expensive to manufacture, and at the same time is a better pole piece since increased contact area is provided. This is achieved by providing a generally rectangular pole piece which has an inwardly projecting lip which overlaps the magnet to prevent the pole piece from being pulled from the housing.

Accordingly, a further and more specialized object of this invention is to provide an improved pole piece having greater contact area and at the same time a construction which permits less expensive and longer-lived dies to be used.

A further more specialized object of this invention is to provide such an improved pole piece with a lip to form the projection which overlaps the magnet.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective view of a lavatory door which employs one of the improved magnetic holders;

Figure 2 is a sectional view of one of the improved magnetic door holders and a fragmentary sectional view of a door and door frame, the door holder being mounted in the door;

Figure 3 is an end elevational view of an improved magnetic door holder and a fragmentary sectional view of a metal panel in which the door holder has been mounted; and,

Figure 4 is an exploded view of one of the improved door holders and the fragmentary portion of a door or door frame for receiving the door holder.

Referring to the drawings, a door shown generally at 16 is carried by a frame 11. The door 10 has a panel 12. An aperture 13, which is preferably rectangular, is formed in the panel 12.

A holder shown generally at 20 is mounted in the aperture 13. It will be apparent that the holder 20 may be mounted in either the frame 11 or the door 10 in many applications. The general custom is to mount such holders in the door becausethe aperture 13 generally may more easily be formed in a door panel than in a frame panel. 9

The holder 20 has a housing-shown generally at 2 45.

The housing has a face wall 21, a back wall 22 and

side walls

23, 24. The

walls

21, 22, 23, 24 define a tubular open-ended cavity 27. The face wall 21 is extended to provide a face flange'2'5. This flange 25 extends past the

side walls

23, 24. In the preferred form, for the sake of appearance and for strength, the face flange 25 extends about the entire perimeter of the face 21. As will be apparent from the subsequent description, only segments of this face flange need be provided for functional purposes.

Snap

rib flanges

29, 30 are formed on the

side walls

23, 24 respectively. In the preferred plastic form for thehousing 26 the

snap flanges

29, 30 are cast integrally as" rib extensions of the

side walls

23, 24.

To achieve one of the outstanding features of the invention, the housing 26 is formed of a yieldable material. When the housing is pressed into the panel aperture 13 some yielding will be experienced in each of the walls of the housing. The principal yielding will occur in the housing projection formed by the

side Walls

23, 24 and the back wall 22, which may have a longitudinal slot formed through it to aid in the yielding. The snap flanges 29, 30 will, of course, yield with the

side walls

23, 24. Through this improved construction which distributes the yielding throughout the entire housing 26, exceptional results have been obtained. A housing constructed in conformance with this teaching can be used repeatedly. This novel construction permits the housing 26 to be removed from the aperture 13 without damage and thus the housing may be used repeatedly or removed for the replacement of a weakened magnet or the like.

As can best be seen in Figure 3, first panel receiving recesses 21 are defined by face flanges 25 and snap flanges 29. Second panel receiving recesses 22 are defined by face flanges 25 and snap flanges 30. When the housing 26 has been fully inserted in the aperture 13 the housing will snap outwardly to its original position and lock the housing firmly to the panel 12 with the panel extending into the

recesses

21, 22. This may best be seen in Fig- 'ure 3.

A magnet 34 together with

pole pieces

35, 36 form a magnet member.

Thepole pieces

35, 36 have an improved and outstanding construction.

Lips

38, 39 are provided on the

pole pieces

35, 36 respectively. The

lips

38, 39 overlap rear surface 48 of the magnet 34 to prevent the

pole pieces

35, 36 from being pulled from the housing 26 when the door is opened.

The

pole pieces

35, 36 have smooth magnet contacting face surfaces 49, 50 which abut end surfaces 51, 52 respectively of the magnet 34. The pole pieces are made of magnetic material and carry an induced magnetism transmitted from the magnet 34.

The

pole pieces

35, 36 are four-sided and preferably rectangular having striker surfaces 40, 41 respectively. The striker surfaces 40, 41 extend over the entire transverse extent of; the pole pieces. Prior known shoulders which prevented pole pieces from being pulled from the housing have been eliminated. Thus, the wide striker surfaces 40, 41 provide improved holder performance and greater closing strength for a magnet of a given size.

In their preferred and disclosed form the

lips

38, 39 are formed by distending the

pole pieces

35, 36 respectively. The lips are quite thin, as measured normal to the striker surfaces 40, 41 to provide a compact assembly. In the preferred and disclosed form the lip dimension normal to the striker surfaces is less than the thinnest dimension of the polepieces.

These improved pole pieces may be formed with one stroke of a simple die which blanks out a rectangular piece, forms a slit between the pole piece face surface and the lip and at the same time distends the lip. Though these pole pieces are somewhat larger than prior known pole pieces, the difference in the material is negligible so far ascost is concerned since the increased material was 4 wasted scrap material in the prior T-shaped construction. Thus, the improved pole pieces have both better operating characteristics and simpler manufacture as well as lower cost of manufacture.

In assembly the magnet 34 is inserted in the cavity 27. The pole pieces are then placed in the cavity. The striker surfaces 40, 41 are passed through

apertures

45, 46 respectively. The pole piece faces 49, 50' are then brought in abutting relationship with the magnet ends 51, 52 respectively. The

lips

38, 39 extend towards one another and contact the rear surface 48 of the magnet.

A further outstanding advantage of this magnetic door holder has been provided and may best be seen in Figure 2. A rib 43 is formed as a portion of the face wall 21. The rib 43 extends inwardly into the cavity 27 The magnet 34 has front surface 44 which is in pivotal or rockable contact with the rib 43. The entire magnet member may pivot on the rib 43 to permit the magnet member to be self-aligning. This self-alignment compensates for any misalignment which may exist between the door 10 and the frame 11.

It will be seen that the rib 43 forms a fulcrum having a transversely extending axis. The magnet assembly is operably contactable with the fulcrum and pivotal or rockable about the axis of the fulcrum. Thus it will be seen that the concept in essence consists of providing means in the housing to co-act with the magnet assembly and permit the magnet assembly to rock about a transverse axis.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in the details of description and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

l. A magnetic door holder assembly adapted for repeated insertion in an aperture in a panel comprising; a housing having a face wall, a back wall and first and second side walls; the walls defining a magnet cavity therebetween, a permanent magnet disposed in said cavity, said face wall having first and second pole piece apertures therein, first and second pole pieces in abutment with the ends of the magnet and each extending into one of the pole piece apertures, said face wall including laterally extending flange portions extending outwardly past said side walls, said side walls each having at least one external rib projection disposed transversely with respect to said flange portions, said external ribs each having first and second ends and a tapering thickness dimension increasing from the first to the second end, the second end of each rib being disposed between the first end and one of the flange portions, the second end of each rib being spaced from said flange portion to define a panel receiving recess therebetween, said housing being formed of a yieldable material, and said walls including the ribs being yieldable to permit repeated positioning of the entire assembly in a panel aperture with side edges of the panel disposed in said recesses and to permit repeated removal therefrom of the entire assembly as a unit.

2. A magnetic door holder assembly adapted for repeated insertion in an aperture in a panel comprising; a housing having a face wall, a back wall and first and second side walls; the walls defining a magnet cavity therebetween, a permanent magnet disposed in said cavity, said face wall having first and second pole piece apertures therein, first and second pole pieces in abutment with to said flange portions, said external ribs each having first and second ends and a tapering thickness dimension increasing from the first to the second end, the second end :of each rib being disposed between the first end and one of the flange portions, the second end of each rib being spaced from said flange portion to define a panel receiving access therebetween, said housing being formed of a yieldable material, said walls including the ribs being yieldable to permit repeated positioning of the entire assembly in a panel aperture with side edges of the panel disposed in said recesses and to permit repeated removal therefrom of the entire assembly as a unit, and said as sembly including pivot means in abutment with said magnet to permit the magnet and pole pieces to pivot relative to the housing when the device is in use to compensate for door misalignment, said pivot means comprising a projection formed on said face wall between said pole piece apertures and extending into said cavity.

3. A magnetic assembly comprising, a snap-in housing having a magnet receiving cavity therein, the housing having a face wall provided with a pair of apertures, a magnet disposed in the cavity, the magnet having spaced end surfaces and front and rear surfaces, a pair of pole pieces disposed at the opposite ends of the magnet, each of the pole pieces being projectable through one of the apertures of said face wall; each such pole piece comprising a flat magnetic body having a magnet contacting face, an opposite face, and spaced parallel inner and outer ends; the magnet contacting face of each of said pole pieces having a magnet contacting surface in abutment with one of said magnet end surfaces, each of said pole pieces having a punched lip at said inner end, the dimension of each of said lips measured normally to the ends of the pole piece being no wider than the thinnest dimension of the pole piece, the dimension of each of said lips measured parallel to the ends and across one face of its pole piece being less than the transverse dimension of the pole piece measured parallel to the ends and across one face, each of said pole pieces having a transverse slit formed therein when the lip is punched and disposed between said lip and said magnet contacting surface, said lips each extending from the plane of the magnet contacting face toward one another to overlie the magnet rear surface, each of said lips having a surface contacting said magnet rear surface, the lip surface of each pole piece being in the plane of said slit and substantially normal to said magnet contacting surface, and each of said pole piece opposite faces having a depression at said inner end, the depressions being formed in the pole pieces by the punching of said lips.

References Cited in the file of this patent UNITED STATES PATENTS 1,252,289 Murray Ian. 1, 1918 1,784,256 Stout Dec. 9, 1930 2,269,149 Edgar Jan. 6, 1942 2,514,927 Bernhard July 11, 1950 2,690,349 Teetor Sept. 28, 1954 2,701,158 Schmitt Feb. 1, 1955