US3553627A

US3553627A - Molded electric plug with flexible holding magnet

Info

Publication number: US3553627A
Application number: US743122A
Authority: US
Inventors: John M Gerber
Original assignee: Essex International Inc
Current assignee: Essex International Inc
Priority date: 1968-07-08
Filing date: 1968-07-08
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

AN ELECTRIC PLUG IS MOLDED WITH CONNECTED BLADES AND CORD, AND WITH A RECTANGULAR FLEXIBLE MAGNET IN ONE OF TWO OPPOSITE GRASPONG SURFACES OF THE PLUG SO THAT THE PLUG CAN BE MAGNETICALLY HELD ON A SURFACE OF MAGNETIC MATERIAL. THE PLUG MAY BE MOLDED WITH THE BLADES AND CORD AND WITH A RECTANGULAR RECESS IN THE GASPING SUR-

FACE. SUBSEQUENTLY, THE FLEXIBLE MAGNET IS INSERTED INTO THE RECESS AND HELD BY FRICTION.

Description

J. M. GERBER 3,553,627

Jan. 5, 1971 MOLDED ELECTRIC PLUG WITH FLEXIBLE HOLDING MAGNET 2 Sheets-Sheet -1 Filed July 9, 1968 INVENTOR. JOHN M. GERBER My A ORZZ Jan 5, 1971 L J. M. GERBER 3,553,627

MOLDED ELECTRIC PLUG WITH FLEXIBLE HOLDING MAGNET Filed July 8. 1968 2 Sheets-Sheet 2 INVENTOR. JOHN M. GERBER A TORN United States Patent US. Cl. 339-12 6 Claims ABSTRACT OF THE DISCLOSURE An electric plug is molded with connected blades and cord, and with a rectangular flexible magnet in one of two opposite grasping surfaces of the plug so that the plug can be magnetically held on a surface of magnetic material. The plug may be molded with the blades and cord and With a rectangular recess in the grasping surface. Subsequently, the flexible magnet is inserted into the recess and held by friction.

BACKGROUND OF THE INVENTION My invention relates to a molded electric plug with a holding magnet, and particularly to an improved molded electric plug having a flexible permanent magnet that is molded with the plug or that is insertedand held by friction in a recess in the plug.

Electric plugs have previously been provided with permanent magnets to hold the plug on a surface of magnetic material so that the plug and cord are out of the way or provide a neat appearance. Two such previous plugs are shown in US. Pat. No. 2,709,245 granted to W. J. Schneider on May 24, 1955; and in US. Pat. No. 2,721,717 granted to H. Wales on Oct. 25, 1955. While such previous plugs are satisfactory in many instances, the plugs also have some disadvantages. Where the permanent magnet is of conventional material, the magnet either must have a special shape so that it will be held in the plug, or must be molded with some plug material over the magnet to hold it in the plug. The special shape may make the magnet more expensive or less effective, and the magnet with plug material over it makes the magnet less effective. A magnet of conventional material requires precautions in order that the magnetic ma terial does not short-circuit the plug blade or cord. Some molded magnets and plugs have an unsymmetrical configuration that is hard to grasp.

Accordingly, an object of my invention is to provide a new and improved electric plug which is molded with plug blades, a cord, and a permanent magnet at an outer surface of the plug.

Another object of my invention is to provide a new and improved molded electric plug with plug blades and cord, and with a permanent magnet that can be inserted later and held in a recess in the plug by friction.

Another object of my invention is to provide a new and improved molded electric plug having a permanent magnet that is positioned at the plug surface for good effectiveness, that does not interfere with the use of the plug, and that makes the plug relatively easy to grasp for insertion and withdrawal.

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Another object of my invention is to provide a new and improved molded electric plug having a permanent magnet that is relatively flexible so that the magnet can be molded with a plug or can be easily inserted in a finished plug, so that the magnet has effective holding force, and so that the plug can be easily and firmly grasped.

SUMMARY OF THE INVENTION Briefly, these and other objects are achieved in accordance with my invention by an electric plug that is molded of suitable rubber or plastic with connected blades and cord. The electric plug has two opposite and preferably diverging grasping surfaces. A flexible permanent magnet having a rectangular shape is preferably molded with the plug at one of the grasping surfaces. The magnet is frictionally held in the formed rectangular recess. The magnet is shaped and positioned to provide a broad surface of the magnet at the one grasping surface so that the magnet provides elfective holding and so that the plug can be easily and firmly grasped.

BRIEF DESCRIPTION OF THE DRAWING The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the claims. The structure and operation of my invention, together with further objects and advantages, may be better understood from the following description given in connection with the accompanying drawing, in which:

FIG. 1 shows a view of an electric toaster having a molded electric plug in accordance with my invention provided on the toaster cord to hold the cord in a neat and out-of-the-way fashion;

FIG. 2 shows a perspective view of a molded electric plug and a permanent magnet in accordance with my invent-ion, the magnet being withdrawn from its recess in the plug;

FIG. 3 shows a plan view of my plug of FIG. 2 with the magnet inserted in the plug recess; and

FIG. 4 shows a cross-sectional view of my plug and magnet of FIG. 3, FIG. 4 being taken along the line 44 in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, I have shown, as an example, an electric toaster having a plug 10 constructed in accordance with my invention and a cord 12 connected to the plug 10 and the toaster. When the toaster is not used or is to be stored, it is sometimes desirable to keep the cord 12 and its plug 10 out of the way. This can be done by wrapping the cord 12 around the upper metallic portion 8 of the toaster, and then holding the plug 10 on this metallic portion 8 by magnetic attraction to the magnetic material in the portion 8. Thus, the cord 12 and the plug 10 are kept out of the way and the toaster has a neat and compact appearance.

With respect to FIGS. 2, 3, and 4, I have shown the details of the construction of the electric plug 10 in accordance with my invention. The electric plug 10 may be molded of a suitable electrically insulating material such as rubber, synthetic rubber, or plastic. Before the plug 10 is molded, blades 14 are connected to the conductors of the cord 12 by any suitable means such as crimping or welding. The blades 14 and part of the cord 12 and a flexible permanent magnet 30 are positioned in the plug mold, and the plug is then integrally molded with the blades 14, the cord 12, and the permanent magnet 30. Since the exact details and configuration of the blades 14 and the cord 12 are not a part of my invention, I have not shown their exact construction, connection, or configuration. The outer configuration of my molded plug 10 comprises a front from which the blades 14 extend and a rear from which the cord 12 extends. The plug 10 has sides which may be ridged near the front 15 and which may be flat and parallel near the rear 20, as shown. Two

opposite grasping surfaces

16, 18 extend from near the front 15 of the plug 10 in diverging directions, and terminate at the rear 20. When molded, the grasping surface 16 is formed with a generally rectangularly shaped recess 22 having a bottom surface that lies in a plane substantially parallel to the grasping surface 16. The front end of the recess 22 has a rounded front wall 24 which extends upwardly above the grasping surface 16, and a rectangular rear wall 26 which also extends upwardly above the grasping surface 16. The other grasping surface 18 may be ridged so that it can be more firmly grasped.

The rectangularly shaped permanent magnet 30 is preferably shaped and positioned so that it has a thickness greater than the distance from the bottom of the recess 22 to the top of the front and

rear walls

24, 26. The permanent magnet 30 is preferably of the flexible type composed of any suitable combination of plastic and magnetic materials such as taught and described in US. Pat. No. 3,124,725 granted to C. W. Leguillon on Mar. 10, 1964. Since such materials do not, by themselves, form a part of my invention, their composition and manufacture are not described in detail.

If the permanent magnet 30 is molded with the plug 10, the recess 22 is formed during the molding. The porosity of the flexible magnet material is greater than the porosity of conventional iron or steel magnets so that there is some bonding between the flexible magnet 30 and the plug 10. However, if the plug 10 is molded to provide the recess 22 (without the permanent magnet 30), the magnet 30 may be inserted into the formed recess 22. This is done by placing the rear end of the magnet 30 against the rear wall 26, bringing the front end of the magnet 30 down and over the rounded top of the front end or wall 24, and snapping the permanent magnet 30 into its recess 22. A small amount of adhesive material may be used. After being molded with the plug 10 or inserted in the recess 22 in the plug 10, the permanent magnet 30 has the position shown in FIGS. 3 and 4. I have found that the rubber or plastic material used for the plug 10 and the material used for the flexible permanent magnet 30 have a relatively high coefficient of friction so that the magnet 30 is securely held in the recess 22. I prefer that the length of the permanent magnet 30 be slightly longer than the distance between the facing surfaces of the front and

rear walls

24, 26. This slight oversize holds the permanent magnet 30 more firmly in its recess 22. Once the permanent magnet 30 is positioned in its recess 22, its outer surface and the grasping surface 18 form convenient and diverging surfaces which can be firmly grasped. The permanent magnet 30 is firmly held in the recess 22, and its upper surface projects sufliciently beyond the plug 10 so that it can effectively contact and hold the plug 10 to a surface of magnetic material.

It will thus be seen that my invention provides a new and improved electric plug which can be molded with its blades and cord, and which can then be provided with a. permanent magnet. The permanent magnet can be molded with the plug or can be easily inserted in the appropriately shaped recess, and is firmly held in the recess. The permanent magnet has an outer surface that effectively engages a surface of magnetic material so that the plug is firmly held by the magnetic attraction. There is no plug material over or outside of the permanent magnet, so that the magnets effectiveness is not reduced. Also, the permanent magnet provides a surface that can be firmly grasped and held by a person. While I have shown only one embodiment of my invention, persons skilled in the art will appreciate that modifications may be made. For example, the plug and magnet can be used with various cords and appliances. The front and

rear walls

24, 26 are not absolutely essential, although they do assist in holding the permanent magnet in position. The magnet 30 may extend a greater or a less distance above the grasping surface. Also, it is not essential that 15 the grasping

surfaces

16, 18 diverge. If the surfaces do diverge, the angle of divergence can be made to provide a canvenient and comfortable feel for grasping the plug. Therefore, while my invention has been described with reference to a particular embodiment, it is to be understood that modifications may be made without departing from the spirit of the invention or from the scope of the claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An improved molded electric plug comprising:

(a) an integral plug of molded electrically insulating material;

(b) said plug having a front, a rear, and at least two opposite grasping surfaces that extend from a location near said front to said rear;

(c) said plug having at least two blades extending from said front and a cord connected thereto and extending from said rear, said blades and said cord being at least partially contained within said plug;

(d) one of said grasping surfaces having a recess therein of a selected size and configuration;

(e) and a flexible permanent magnet comprising a combination of plastic and magnetic materials posi tioned in said recess, said magnet having substantially the same size and configuration of said recess so that the outer surface of said permanent magnet is at least as high as said one grasping surface.

2. The improved plug of claim 1 wherein said opposite grasping surfaces diverge from said front to said rear.

3. An improved molded electric plug comprising:

(a) an integral plug of molded electrically insulating material;

((1) one of said grasping surfaces having a rectangularly shaped recess therein of a selected length between said front and rear, a selected width transverse to said length, and a selected depth transverse to said length and extending inward from said one surface;

(e) and a flexible rectangularly-shaped permanent magnet comprising a combination of plastic and magnetic materials positioned and frictionally held in said recess, said magnet having substantially said recess length and width and a depth that is greater than said recess depth so that the outer surface of said permanent magnet formed by said length and width is outward of said one grasping surface.

4. The improved plug of claim 3 wherein said opposite grasping surfaces diverge from said front to said rear.

5. The improved plug of claim 3 wherein said one grasping surface has a wall at the front and rear ends of said recess, each of said walls extending outwardly beyond said one grasping surface to engage the respective 75 ends of said permanent magnet.

6. The improved plug of claim 5 wherein said opposite grasping surfaces diverge from said front to said rear.

References Cited UNITED STATES PATENTS 6 2,721,717 10/1955 Wales 339-12X 3,093,434 6/1963 Francis 339-195 3,321,730 5/1967 Schlangen 33912 MARVIN A. CHAMPION, Primary Examiner P. A. CLIFFORD, Assistant Examiner US. Cl. X.R. 339--45