US2186578A - Electric cord set - Google Patents

Description

Jam F. c. DOUGHMAN 2,186,578

ELECTRIC CORD SET Filed Dec. 2, 1937 2 Sheets-Sheet l INVENTOR.

WATTORN .V

Jan. 9, 1940. c. DQUGHMAN 2,186,578

ELECTRIC CORD SET Filed Dec. 2, '19s? 2 Sheets-Sheet 2 Patented Jan. 9, 1940 1 UNITED STATES PATENT OFFICE ELECTRIC CORD SET Fer-man O. Doughman, Stamford, Conn., assignor to Electrolux Corporation, Dover, Del., a corporation of Delaware Application December 2, 1937, Serial No. 177,740

3 Claims.

My invention relates to an electric cord set and more particularly. to an electric cord set with means incorporated in it for filtering or by-passing high frequency electric currents.

In the operation of electrical appliances high frequency electric currents may be generated or pulsations produced which do not affect the proper functioning of the appliance. However, these high frequency currents or pulsations, if transmitted through the supply lines, antenna, or ground connectors to a radio circuit, may produce static in the radio circuit and so interfere with the reception of one or more radio programs. While the operation of appliances does not often affect radio reception when radio interference does occur it may be eliminated by connecting a so-called radio filter to the appliance. The radio filter usually consists of condensers connected to the appliance for filtering out or by-passing the high frequency currents or pulsations. In view of the fact that it is seldom that the operation of an appliance will affect radio reception it is not desirable to build a radio filter or interference eliminator into appliances. A radio interierence eliminator which can be conveniently connected to an appliance causing radio interference is highly desirable.

In accordance with my invention, a cord set is provided with a radio filter or interference eliminator incorporated in it which may be used with any appliance that tends to produce radio interference, or may be used with all appliances without the necessity of determining which one of them does produce the interference. By in- O corporating a radio filter in the cord set and covering it with a flexible material it is made rugged so that it will withstand the hard usage to which portable appliances are subjected.

What I consider to be novel and my invention may bebetter understood by reference to the following specification and appended claims when considered in connection with the accompanying drawings, in which Fig. 1 is a view showing a radio filter incorporated in an auxiliary cord set connected between a vacuum cleaner and a conventional cord set;

Fig. 2 is a sectional view of the auxiliary cord set of Fig. 1;

Fig. 3 is an end View of the auxiliary cord set of Fig. 2;

Fig. 4 is a plan view of the auxiliary cord set of Fig. 2;

Fig. 5 is a sectional View along line 55 of .n Y v I Fig. Gis a sectional view taken along the line 66 of Fig. 2;

Fig. '7 is a schematic wiring diagram of the filter;

Fig. 8 is a modified form of cord set;

Fig. 9 is a sectional View along line 99 of Fig. 8; i

, Fig. 10 is a sectional view along line ill-40 of Fig. 8;

Fig. 11 is an end view looking in the direction of arrows HIl of Fig. 8; and

Fig. 12 shows another modified form of cord set.

Referring to the drawings, numeral I0 designates an auxiliary cord set connected between a: vacuum cleaner H and a conventional cord set i2. Vacuum cleaner II is shown by way of an example of a portable appliance with which the invention may be used. Vacuum cleaner II is of the type having a. cleaner unit l3 supported on the floor and moved from place to place by pulling on a flexible conduit or hose M to which is connected a cleaning tool 15. The unit [3 is usually connected to a source of electrical supply by means of a cord set [2. If radio interference shouldbe encountered. in the operation of the appliance it may be eliminated by connecting the auxiliary cord set I0 between the appliance and the usual cord set.

Auxiliary cord set Ill has incorporated in it a radio filter unit IS. A schematic diagram of the filter unit I6 is shown in Fig. 7. Two condensers I! and I8 are connected together at I9- Instead of two condensers a single condenser may be used with a tap intermediate its ends. The condenser I7 is connected to two conductors and 21 which are adapted. to be connected at one end to an appliance and at the other end to a source of electrical supply. The condenser I8 is connected by means of its terminal that is com-- men with a terminal of condenser I! to conductor 2i. The other terminalof condenser I8 is connected to a ground connection at 22. Instead of this ground connection a connection may be made to the frame or casing of the appliance. The condensers l1 and I8 by-pass or suppress the high frequency currents or pulsations so that they are not transmitted over the electrical supply system.

Referring particularly to Figs. 2 to 6, the filte unit 16 is incorporated in the auxiliary cord set l0 adjacent a male plug 23. Two leads 24 and 25 are brought out at one'end of the filter unit l6 one of the leads being connected to a common terminal of two condensers or to an intermediate tap of a single condenser. Athird lead 26 is brought out at the other end of filter unit I6.

While filter unit I6 is shown as of a slender and relatively long cylindrical shape, other shapes or forms of filter unit may be used. Leads 24 and 25 are connected to two terminals 2'! of plug 23 to which conductors 23 and 29 are also connected. Lead 26 is connected to a third conductor 39. Conductors 22 and 29 are connected at their opposite ends to two terminals 3| of a female connector 32. Conductor 39 is connected at its opposite end to a contact 33. Two spacers 34 of disc shape are positioned on filter unit I6 adjacent opposite ends. The spacers 34 are preferably formed of a substantially rigid material such as hard rubber; Two recesses are provided in the spacers 34 through which the conductors 28 and 29 may pass. It may-be found desirable to use more than two spacers .34 de- "alug 4| preventing the connector 32 from fitpending upon the size of the filter unit I6. The spacers 34 perform the-dual functions of protecting the filter unit I 6 from unusual crushing forces and the conductors 28 and 29 from strain tending to sever their connections to the. ter- Ininals 21 byttwisting.

An overall covering 36 of flexible insulating material preferably soft rubber is provided for the auxiliary cord set It]. Covering 36 can best be formed in steps by first forming it on the conductors 28, 29, and 30 and then separately on the filter unit I3 and terminals 27 forming plug :23 .and the terminals 3i forming connector 32. If a rubber compound is used for covering 36 itmay be vulcanized or cured in successive .steps as it is. applied' Plug 23' is provided with a-lip 3.1 integral with covering 36 and extending to. substantially the ends of terminals 2?. Lip 3:7! provides a protective insulating covering for the terminals 27 to prevent a shock or short circuit upon the connection ofa connector 38 of cord set I2 after a plug-.39 has already been connected .to a source of electrical supply. Lip 31 also serves to provide a moisture and waterproof protection for the terminals .21 .when connector 38 is connected to them.

.Contact 33.is carried by connector 32 and extends .exteriorly of the covering 36 at one side of the body of connector 32. When connector 32 is connected to an appliance such as vacuum cleaner II the contact 33 engages a metallic portion of the casing of cleaner unit I3 as at 40. To prevent the reversal in position of the connector 32 so that a good connection between thecasing .of cleaner unit I3 and contact 33 is assured the body of connector .32 is formed with ting butin one position.

.In the use of vacuum cleaners of the type of vacuum cleaner II at times thecleaner unit I3 may, standupright on .its .rear end shown at the right in Fig. 1. Any protuberance extending from the connector 32 may interfere with the placing of the cleaner unit I3 in this position or may be damaged. To prevent such a possibility. the filterunit I6 'is mounted adjacent theplug 23 and sufficient length of conductors 28,29, and 36 provided between the connector 32 and filter unit I6.to permit thebending of the cord set In adjacent the connector 32 without anydanger of damage to the filter unit Hi.

In a modified form of construction shown in Figs. 8 to .;11 filter unit I6 is incorporated in a cordset 42 of sufficient length so that it may be substituted for the conventional .cord set I2 instead of being used in conjunction with. itas in nector 59.

the case of the auxiliary cord set I 0 described above. Similar parts are designated by the same numerals used heretofore. The two leads 24 and connection to a grounded circuit at the recepta'cle or convenience outlet (not shown) to which the plug 45 is connected. 7

The conductors 28 and 29 are connected at their opposite ends to two female terminals 48 and 49, respectively, of a three'contact con- The third terminal 5i of connector 59 located between the terminals 48 and 49 is connected to conductor 39. Terminal 5| is adapted to-complete a connection to the metal frame of the casing of cleaner unit I3 at a point not shown in the drawings. By this arrangement with the terminal 5I for connecting the conductor 58 it does not matter whether the terminal 48 or 49 is positioned at the top so the connector 58 may be connected in either position.

vThe conductor 36 in addition to connecting the casing of cleaner unit I3 to vthe lead 26 of filter unit I6 also connects the casing to ground through wire 46 and prong 41. In some localities the connection of the casing of a portable appliance to ground is considered desirable and in the case of washing machines and similar appliances is required. By using cord set 42 it would be unnecessary to make any other or special connection between the appliancecasing and ground. Two discs 52 of vulcanized fiber or like material are located on the filter unit I6 at opposite ends. Recesses 53 permit the passage of conductors '28, 29, and 36 through the discs 52 and serve to position the conductors around the filter unit I6. To permit a bond between the discs 52 and an overall covering 54 of flexible insulating material a plurality of spaced holes 55 are provided in discs 52 through which the material of covering 54 may extend. It may be found desirable in some cases to omit from the cord set 42 the conductor 39 and terminal 5| or the wire 43 and prong 41. However, one or the other of the connections forlead 26 of filter unit I6 should be provided. In the manufacture of cord set 42 the same steps can be followed as in the case of auxiliary cord set I8.

In the modification illustratedin Fig. 12 the filter unit I6 is combined with a three terminal connector 56. This construction may be used where a protuberance from the connector is of no concern. The leads 24 and 25 are connected to the conductors 28 and 29, respectively, intermediate their ends. The adjacent ends of conductors 28 and 29 are connected to the two outside terminals 51 and 58, respectively, of

connector 56. Lead 26 is connected directly to stituted for the connector 56.

What I claim is:

1. In an electric cord set, a connector having a plurality of electric terminals, a condenser relatively long in comparison to its Width connected to said terminals and located in juxtaposition to said connector, a plurality of substantially rigid spacers surrounding and spaced apart longitudinally along said condenser, and a unitary covering of: flexible insulating material surrounding said connector and said condenser, said rigid spacers acting to protect said condenser from injury by the operator of an appliance with which the said cord set may be associated.

2. In an electric cord set, a connector having a plurality of electric terminals, a plurality of condensers extending longitudinally from said connector, a plurality of substantially rigid discs extending around and spaced apart longitudinally along said condensers, and a unitary covering of flexible insulating material surrounding said connector and said condensers, said rigid disks acting to protect said condenser from injury by the operator of an appliance With which the said cord set may be associated.

3. In an electric cord set, a plurality of electric terminals, an electric condenser relatively slender in comparison with its length connected to said terminals and positioned longitudinally in line with said terminals, a plurality of vulcanized fiber spacers surrounding and spaced apart longitudinally along said condenser, and a unitary covering of flexible insulating material for said terminals and said condenser, said fiber spacers acting to protect said condensers from injury by the operator of an appliance with which the said cord set may be associated.

FERMAN C. DOUGHMAN.

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