US1878014A

US1878014A - Resistor

Info

Publication number: US1878014A
Application number: US501703A
Authority: US
Inventors: William F Steenweg
Original assignee: Allen Bradley Co LLC
Current assignee: Allen Bradley Co LLC
Priority date: 1930-12-11
Filing date: 1930-12-11
Publication date: 1932-09-20
Anticipated expiration: 1949-09-20

Description

' sept. 2o, 1932. w F. STEENWEG 1,878,014

RESISTOR Filed Dec. ll. 1930 wllnlulii j muy M l! L; E

f Patented Sept. 20, 1932 WILLIAM F. STEENW EG, F MILWAUKEE,

WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO ALLEN-BRADLEY COMPANY, 0F MILWAUKEE, WISCONSIN, A. CORPORA- TION 0F WISCONSIN RESISTOR Application led December This invention relates to certain new and useful improvements in resistors particularly adapted for use in the ignition circuit of an automotive vehicle equipped with a radio receiver for the purpose of eliminating the electrical interference of disturbance produced by the discharge of current across the spark plugs during operation of the vehicle.

It is an object of this invention to provide a resistor of the general character described in my copending application Serial No. 390,- 836, filed Sept. 6, 1929, and having means thoroughly shielding and protecting the element against moisture.

Another object of this invention resides in the provision of a resistor of the character described wherein the resistor' elementy per se, is thoroughly shielded but, at the same time, free expansion and contraction of the device under temperature changes is freely accommodated without in any wise disturbing the electrical connections therewith.

A more specific object of this invention resides in the provision of an electrical resistor unit of the character described having a moisture proof` housing of non-conductive material, terminals carried by the housing at opposite ends and electrically connected with the unit and yieldable means within the housing and disposed between the resistor unit and an adjacent terminal to accommodate expansion and contraction of the unit without disturbing the electrical connection of the unit with the terminal.

With the above and other objects in View which will appear as the description proceeds, my invention resides in the novel construction, combination and arrangements of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of lthe hercindisclosed invention may be made as come within the scope of the claims.

In the accompanying drawing, I have il- 11, 1930. Serial No. 501,703.

lustrated two complete examples of the physical embodiment of my invention constructed according to the best modes I have so far devised for the practical application of the principles thereof, and in which Figure 1 is a view, partly in side elevation and partly in longitudinalsection, illustrating my improved resistance unit as applied to a spark plug, only the upper terminal portion of the plug being illustrated;

Figure 2 is a view, partly in elevation and partly in section, of a modified form of resistance unit inserted in the high tension line to the distributor;

Figure 3 is a transverseL sectional view taken through Figure 2 on the plane of the line 3-3; and

Figure 4 is a diagrammatic view illustrat- `ing a conventional ignition circuit of an automotive vehicle esuipped with my improved resistor.

Referring now more particularly to the accompanying drawing, in which like numerals designate like parts throughout the Several views, 5 represents' a spark plug of con- 7. ventional construction having a body mem- Y ber 6 of insulation in which the central electrode, not shown, of the plug is axially embedded the electrode having a threaded stud or other terminal means 7 at its upper end for receiving one end of a terminal 8 of the improved resistor unit indicated generally as 9.

The resistor unit comprises a resistance element 10 molded of a composition of ingredients including a filler, a binder and a conductor in proportions to provide the desired conductive characteristics. The element 10 is of the type covered by Letters Patent Number 1,816,194, i. e., the resistance value of its end portions is materially lower than that of its medial portions. The resistance element is secured Within the bore 11 of a preferably moisture proof protecting housing 12 having one end closed by a metal cap 13 clinched over a bead or ange 14, as at 15, the cap having n A closed by a terminal stud 20 having an inner head 21, a hex head 22 spaced therefrom and an outer threaded end 23, the stud 20 being secured in position by molding the housing 12 thereabout. The threaded end 23 of the stud is adapted to receive a head member 24 for receiving an electrical conductor 32.

The resistor element proper is inserted in the housing 12 from its end closed by the cap 13 prior to the attachment of the cap thereto and a yieldable conductor 25, illustrated in the present instance as being a spring member, is inserted in the bore 11 after the resistance element. Attachment of the cap 13 over the end of the housing places member 25 under compression so that a positive electrical connection between the low resistance ends of the resistance element and the adjacent terminal members is maintained at all times and expansion and contraction of the parts compensated for. The yielding tension afforded by the member 25 also accommodates any variations in the dimensions of elements.

In Figure 4, is illustrated a conventional ignition circuit in which the battery 26, upon closing of an ignition switch 27 is connected with a circuit breaker 28, the stationary contact of which is connected with the primary of an induction coil 29. The secondary of the induction coil 29, as customary, is connected with the distributor arm 30 which cooperates with the ter'minals 31 to select the spark plug to be fired. From the terminals 31 the conductor32 leads to terminals, not shown, electrically connected with the members 24 which in turn are connected with the i electrodes of the spark plug through the resistance element. A resistance element 33 is interposed between the secondary of the induction coil and ground 34, the value of which is preferably the same as that of the units 9 at the different spark plugs, which has been found to be approximately 25,000 ohms, although this value may change as conditions warrant.

The unit 33 is identical with the unit 9 with the exception that in lieu of the terminal 8 at one end a socket type terminal 35 is substituted and in lieu of the type of terminal disclosed at the opposite end of the unit 9 a spring type socket terminal 36 is provided to facilitate its connection with the conventional distributor.

From the foregoing description, taken in connection with the accompanying drawing,

it will be readily apparent to those skilled in the art to which an invention of the character described appertains, that an efficient and practical method of eliminating undesirable oscillations usually ncontended with in an ignition circuit and which, if unprevented, produce excessive interference with radio reception by a receiver located within the receptacle, is provided and further that a highly eiiicient .and practical construction of resistance unit for this purpose is provided.

What I claim as my invention is:

l. A device for eliminating radio interference arising from high frequency oscillations produced by the discharge of a spark plug, comprising a tubular housing of insulating material, a terminal contact at each end portion of the housing, a self-supporting electrical resistance element having its integral end portions of lower resistance value than its medial portion, said element being disposed within the tubular housing to electrically bridge the terminal contacts, and expansible means within the housing for maintaining a tension between the low resistance end partions of the element and the adjacent terminal contacts to insure a good electrical conp nection between the element and the terminal contacts.

2. A device for eliminating radio interference arising from high frequency oscillations produced by the discharge of a spark plug, comprising a tubular housing of insulating material, a terminal contact at each end portion of the housing, a self-supporting electrical resistance element having its integral end portions of lower resistance value than its medial portion, said element being disposed within the tubular housing to electrically bridge the terminal contacts, one low resistance end of the element directly contacting with one terminal contact, and yieldable electrical conducting means between the other low resistance end of the element and the other terminal contact for maintaining tension between it and the adjacent terminal contact and low resistance end portion of the element and between the other low resistance end portion of the element and the other terminal contact to assure a good electrical connection from one terminal contact to the other through the element.

3. A device for eliminating radio interference arising from high frequency oscillations produced by the discharge of a spark plug, comprising a tubular housing of insulating material, a terminal contact at each end of the housing, a self-supporting electrical resistance element having its integra-l end portions of lower resistance value than its medial portion, said element being disposed within the tubular housing to electrically bridge the terminal contacts, yieldable means for maintaining a tension between the low resistance 'end portions of the element and the adjacent terminal contact to insure a good electrical connection between the element and the terminal contacts, means exteriorly of the housing facilitating the readily detachable connection therewith of a conductor, and a combination mounting bracket and conductor electrically connected with the other terminal contact and adapted for connection with the electrode of a spark plug whereby the unit is supported therefrom.

4. A device for eliminating radio interference arising from high frequency oscillations produced by the discharge of a spark plug, comprising a tubular protecting housing of insulating material, a terminal contact at one end of the housing, a terminal exteriorly of the housing and in electrical connection with said terminal contact, a self-supporting electrical resistance element having integral end portions of lower resistance value than its medial portion within the housing and adapted to have one end abutting said terminal Contact, a cap member secured over the other end of the tubular housing, a terminal contact carried by the cap member and adapted to be electrically connected with the other low resistance end of the resistance element, yieldable electrical conductor means engaging one end of the resistance element to maintain a tension between the element and the terminal contacts, and a mounting bracket and terminal fixed to and supported solely from the cap member for mounting the dev1ce.

In testimony whereof I have hereunto affixed my signature.

WILLIAM F. STEENWEG.