US3600531A

US3600531A - Self-shorting phono plug

Info

Publication number: US3600531A
Application number: US35830A
Authority: US
Inventors: Otto Hoegerl
Original assignee: NAT TEL TRONICS CORP
Current assignee: NAT TEL TRONICS CORP; NATIONAL TEL-TRONICS CORP
Priority date: 1970-05-08
Filing date: 1970-05-08
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17

Abstract

A self-shorting plug for use in connection with a phonojack including a conventionally configured centrally disposed prong, a surrounding outer body member, and a flat steel shorting spring staked at one end thereof to the border of a centrally disposed opening in said outer body member, and having a free end terminal penetrating a slotted opening in a skirt portion of said outer body member to contact a surface of said prong.

Description

llnitnd States Patent inventor Otto Hoegerl Saegertown, Pa.

Appl. No. 35,830

Filed May 8, 1970 Patented Aug. 17, 1971 Assigriee National Tel-Tronics Corporation Yonkers, NY.

SELF-SHORTING PHONO PLUS 2 Claims, 4 Drawing Figs.

U.S. Cl 200/511, v 339/177 E int. l ..1Hl0lr 33/30 Field of Search 339/19,

[5 6] References (Iited UNITED STATES PATENTS 3,045,079 7/1962 Frantz et a1 ZOO/51.1 3,387,l04 6/1968 Friend ZOO/51.1

Primary Examiner- Stephen J. Novosad Assistant Examiner-Lawrence J. Staab Attorney-Charles E. Temko SELF-SHORTING PHONO PLUG This invention relates generally to the field of electronic hardware, and more particularly to an improved self-shorting phonoplug of a type used to interconnect a phonograph head to an amplifier-or similar structure. Devices of this general type are well known in the art, and the invention lies in specific constructional details.

Phonoplugs are characterized in the provision of a centrally disposed prong surrounded by a cylindrical main body member, one end of which is provided with a resiliently expandable skirt which engages the outer surface of a cor responding jack, while the centrally disposed prong penetrates a corresponding opening in the jack. The prong and body member are mutually electrically insulated by a planarfiber washer, and an opening in the body member permits communication of a conductor with the inner end of the prong.

For some installations, it is desired to use a self-shorting plug, in which means is provided for, electrical interconnection between the body member and the prong when the plug-is in disengaged position with respect to the corresponding jack. This is accomplished by means of a spring formed of wire, one end of whichis secured about the centrally disposedopening in the body member, and another end of which penetratesone of the slots in the resilient skirt on the body member to contact an outersurface of the prong adjacent an inner end thereof. This spring is moved out of theway when the plug is inserted within a jack, and then contacts the outercylindrical surface of the jackto assist in completing thecircuit. in prior art constructions, the spring is fonned of piano wire suitably plated, and is relatively fragile, to be easily damaged by manual handling, particularly when considerable force must be applied to the device at the time of interconnection or disconnection with a jack. Because of the delicate construction, difficulty has beenencountered in maintaining positive contact. Further, the spring has been difficult to manufacture to a uniform standard, and as a result, the variance in resiliency has been excessive. A further disadvantagehas been the. ten dency for the staking of the springat the fixed end thereof to loosen, owing to the difiiculty in obtaining proper purchase upon narrow gauge wire, so that the terminal becomes misaligned with the slot in the outer body member, and is unable to make proper contact. a

It is therefore among the principal objects of the present invention to provide an improvedself-shorting phonoplug of the class described, in which the above mentioned disadvantages have been substantially eliminated;

Another object of the invention lies inthe provision of an improved shorting spring which may be readily incorporated into existing phonoplug constructions without modification of the latter.

Yet another object of the invention lies in the provision of an improved self-shorting phonoplug of the class described, in which'the cost of manufacture may be of a reasonably low order, directly comparable with existing prior art constructions, thereby permitting consequent wide sale, distribution and use.

Yet another object of the invention lies in the provision of a shorting spring for use in conjunction with phonoplugs' which may be formed as a metallic stamping with improved shaperetaining properties.

These objects, as well as other incidental ends and ad vantages, ,will more fully :appear in the progress of the following disclosure, and be pointedoutin the appended claims.

lnwthe drawing, to which reference will be made in the specification, similar reference @characters have been employed to designate corresponding parts throughout .the several views. p

FIG. 1 is a side elevational view, partly broken away in section of an embodiment of the invention.

FIG. 2 isaside elevational view of the shorting spring forming a part of the'embodiment.

FIG..3 is a bottomplan view of the shorting spring.

FIG. 4 is a view in elevation of a. stamped blankfrom which the shorting spring is formed. 1

In accordance with the invention, the device, generally indicated by reference character 10, comprises broadly: an elongated axially disposed prong 11, an insulating member 12, an outer body member 13, and a shorting spring 14-.

The prong 11 may be of entirely conventional construction, including an outer end 17 which is preferably rounded to facilitate insertion into a jack (not shown), and an inner end 18 defining first and second flanges 19 and 20, respectively, for engagement with the insulating member 12.

The insulating member 12 is preferably of planar fibrous material, having a central opening 23 disposed between the flanges 19 and 20, and a peripheral edge 24 corresponding in diameter to the inner diameter of the outer body member 13.

The outer body member 13 is preferably formed as the product of a metallic drawing operation, and includes a slotted skirt 27, the inner surface 28 of which makes contact with the outer surface of a jack in well-known manner. The skirt 27 is interconnected by a tapered portion 29 to an upper cup portion 30 having an upper wall3l forming a central opening 32 bounded by a beaded edge 33, as is known in the art.

The shorting spring 14 is preferably formed as a metallic stamping indicated by reference character 34 in FIG. 4, and includes a first end 35 having a hole 36 defining edge segments I 37 which are preferably corrugated to permit convenient staking. A tapered portion 38 communicates with a second end 39 having alaterally extending tab 40.

Referring to FIGS. 2 and 3' in the drawing, the spring is shaped to provide a planar mounting portion 42, interconnecting with an arcuate portion 43, in turn leading to a longitudinally disposed planar portion 44. The tab 40 is bent with respect to the plane of the portion 44 to form a terminal indicated by reference character 45 The device is assembled in well-known manner, in which the insulating member 12 is first affixed to the prong- 11, and subsequently forced within the outer body member 13. The spring 14' is attached thereto by staking over the edges of the central opening 32 upon the edges 37 of the hole 36 after aligning the terminal 45 to project through one of the slots in the skirt 27.

As will be understood from a consideration of FIG. 1, the resiliency of the spring 14 is such that when the device 10 is disengaged with respect to a jack, the terminal will contact the outer surface of the prong 11. Upon engagement with a jack, the rounded edge 46 of the terminal 45 will serve as a camming surface to urge the same radially outwardly, to permit full engagement of the plug with respect to the jack, and allow the edge to rest on the outer surface of the jack to assist in completing an electrical communication therethrough. Upon withdrawal of the plug, the spring. will return to its relatively unstressed condition, providing an immediate short.

It is to be understood that it is not considered that the invention lies within the specific details of structure shown and set forth in this specification, for obvious modifications will occur to those skilled in the art to which the invention pertains.

What I claim is:

1. A self-shorting plug for use witha corresponding jack comprising: a centrally disposed prong; a cup-shaped outer body member surrounding said prong; insulating washer means interconnecting said prong and said outer body member; said outer'body member having a centrally disposed orifice therein, and spring mounting means surrounding said orifice, said body member having a slotted skirt generally coaxially surrounding said prong; and ashorting spring interconnectedat one end thereof to said spring mounting means, andhaving a second end projecting through said slotted skirt to resiliently contact a surface of said prong; said spring being of planar configuration, and including a first end portion having a generally circular opening therein, an arcuate portion connected to said first end portion, and a second end portion penetrating said slotted skirt connectedto said arcuate portion.

member by staking of an edge of said cen trally disposed ori-

Claims

1. A self-shorting plug for use with a corresponding jack comprising: a centrally disposed prong; a cup-shaped outer body member surrounding said prong; insulating washer means interconnecting said prong and said outer body member; said outer body member having a centrally disposed orifice therein, and spring mounting means surrounding said orifice, said body member having a slotted skirt generally coaxially surrounding said prong; and a shorting spring interconnected at one end thereof to said spring mounting means, and having a second end projecting through said slotted skirt to resiliently contact a surface of said prong; said spring being of planar configuration, and including a first end portion having a generally circular opening therein, an arcuate portion connected to said first end portion, and a second end portion penetrating said slotted skirt connected to said arcuate portion.

2. Structure in accordance with claim 1, said circular opening having a corrugated edge secured to said outer body member by staking of an edge of said centrally disposed orifice.