US3897125A

US3897125A - Captivated grounding spring

Info

Publication number: US3897125A
Application number: US488176A
Authority: US
Inventors: Norman R Anderson
Original assignee: Bunker Ramo Corp
Current assignee: Amphenol Corp
Priority date: 1974-07-12
Filing date: 1974-07-12
Publication date: 1975-07-29
Anticipated expiration: 1992-07-29
Also published as: CA1027652A; JPS5131883A; FR2278178A1; JPS5824909B2; GB1514502A; DE2528186A1; FR2278178B1

Abstract

The following specification describes a grounding spring and connector shell assembly in which the grounding spring has a split annularly shaped portion for entry into the connector shell. A split lip at the rear axial end of the split portion is provided for seating behind an internal shoulder on the connector shell. An axially extending key on the internal surface of the shell engages between the end segments of the lip. The front axial end of the annularly shaped portion has folded back circumferentially spaced spring fingers for engagement over the connector shell external surface adjacent the front end of the shell and for engagement against the internal surface of a mating shell.

Description

nite States Fi atet [191- Anderson CAPTIVATED GROUNDING SPRING Inventor: Norman R. Anderson, Cicero, lll.

Assignee: Bunker Ramo Corporation, Oak

Brook, 11].

July 12, 1974 Filed:

Appl. No.:

References Cited UNITED STATES PATENTS 10/1970 Queirolo et a1. 339/66 R X 8/1974 Oberdiear 339/14 L X [4 1 July 29,1975

Primary ExaminerRoy Lake Assistant ExaminerDeWalden W. Jones Attorney, Agent, or FirmNorton Lesser; F. M. Arbuckle [57] ABSTRACT The following specification describes a grounding spring and connector shell assembly in which the grounding spring has a split annularly shaped portion for entry into the connector shell. A split lip at the rear axial end of the split portion is provided for seating behind an internal shoulder on the connector shell. An axially extending key on the internal surface of the shell engages between the end segments of the lip. The front axial end of the annularly shaped portion has folded back circumferentially spaced spring fingers for engagement over the connector shell external surface adjacent the front end of the shell and for engagement against the internal surface of a mating shell.

13 Claims, 7 Drawing Figures 1.2 :1. is E SHEET PATENTED JUL 2 9 I975 FIG-:3

FIG.4-

1 CAPTIVATED GROUNDING SPRING BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to grounding springs for electrical'connectors and more particularly to an improved and more economical grounding spring and connector shell assembly.

2. Summary of the Prior Art Customarily, a grounding spring is provided between telescopingly engaged metal connector shells for insuring the shells are grounded when they engage or mate. The spring is usually secured to an associated one of the shells by soldering, welding, swaging or magneforming, for example. Securing the spring to the shell by means of soldering or the like presents time consuming and expensive assembly problems.

Alternatively, springs in the shape of a split ring have been secured to the outer periphery of a shell and seated in spaced axially extending undercuts or recesses on the shell outer periphery but these springs must usually be deformed manually prior to fitting on the shell, while the provision of the axially extending recesses is expensive. Another form of a split ring having axially extending cantilever spring contact fingers utilizes a radial flange and is expanded to fit over the shell and then allowed to contract for fitting the flange in a recess of the shell, however, electrical engagement and retention are uncertain.

SUMMARY OF THE INVENTION In the present invention, a grounding spring having an annular configuration or ring shaped portion is provided for engaging against the inner surface of the supporting shell on which the spring is carried or mounted, with the ring shaped portion having a radially outwardly extending annularly shaped lip at the rear axial end and folded back cantilever grounding spring fingers at the front axial end. The spring fingers are overlappingly spaced from the ring shaped portion for nestingly receiving the front end of the shell between the fingers and ring shaped portion. The fingers therefore engage the adjacent surfaces of the telescopingly engaged connector shells to electrically connect the shells.

The annularly shaped lip formed at the one axial end of the ring shaped portion fits or engages behind and against an internal radial shoulder on the supporting connector shell so that the spring cannot move axially. The ring shaped portion and lip also have a split or passageway for receiving a key on the internal surface of the supporting shell. The key is normally provided for aligning the dielectric carrying, the contacts in the shell and it also serves for aligning the grounding spring and holding the spring against rotation. The location of the end segments of the split annularly shaped portion and lip in the shell protects the same against damage.

Thus assembly of the ring to the shell is provided very simply by insertion of the forward end of the shell between the spring fingers and the ring shaped portion. The split in the ring permits circumferential reduction of the ring and lip as axial pressure is applied to move the lip and ring axially of the shell with ease and without permanent or excessive deformation since the deformation is automatically controlled by the shell wall to seat the lip behind the shell shoulder with the shell key aligned with the opposite ends of the split or passageway in the lip. The ring, of course, expands for seating the lip behind the shell shoulder in response to the lip passing the shoulder. With the key engaging in the lip passageway, proper rotational positioning of the spring is provided.

In essence, by securing the lip in one shell surface and engaging the front end of the shell between the fingers overlapping the other shell surface an extremely secure, economical and electrically effective grounding spring is obtained. The split ring portion, lip, fingers, shoulder and key thus provide a simply fabricated economical, easily assembled arrangement for securely retaining the grounding spring.

It is therefore a primary object of the present invention to provide an improved and more economical grounding spring for use in a connector shell assembly.

Other objects and features of the present invention will become apparent on examination of the following specification and claims together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a portion of a connector and the grounding spring;

FIG. 1a is an enlarged fragmentary sectional view of a portion of the shell and spring;

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along the line 33 in FIG. 1;

FIG. 4 is a developed elevational view of the grounding spring before forming into an annular shape;

FIG. 5 is an end elevational view of the grounding spring shown in FIG. 4; and

FIG. 6 is a front elevational view of the grounding spring formed in an annular shape.

DESCRIPTION OF THE INVENTION In FIG. 1, a connector assembly is indicated by the reference character 10. The assembly comprises a float or resiliently mounted connector shell 12 which may have guide bushing means 14, for example, to receive guide pin means 16 on a second connector shell 18 for guiding and aligning the connector shells l2 and 18. Shell 18 has an annularly shaped front end portion 20 for telescoping engagement over an annularly shaped front end portion 22 of shell 12. In this case, the connector shells may be rack and panel mounted with a dielectric insert assembly such as 24 provided in each shell for carrying and retaining a plurality of contacts such as 26, each engaging respective contact 28 of a plurality of contacts carried by a dielectric insert assembly in the mating or engaged connector shell 18.

A bayonet key such as 30 on the front end 20 of shell 18 engages in a keyway or slot 32 provided in an overlapping ring portion 34 on shell 12 for insuring correct alignment between the shells or for use in shell alignment in the event the guide pin and guide bushing means are omitted. A seal 36 is positioned between the end of connector shell 18 and a radially outwardly extending shoulder 38 on connector shell 12.

A split ring grounding spring 40 is engaged with the front end of shell 12. Spring 40 comprises an annularly shaped portion 42 as best seen in FIG. 6 with opposite end segments of the portion 42 defining an axially extending split or passageway 44. At the front or one axial end or edge of annularly shaped portion 42, a plurality of cantilever folded back spring fingers 46 are provided that project axially back over portion 42 in overlapping radially outwardly spaced relationship to the portion 42. The fingers 46 are engaged between the external peripheral surface of the front end of connector shell 12 and the internal peripheral surface of the front end of connector shell 18. The fingers 46 are located in spaced circumferential positions and are generally equispaced as seen in FIG. 4, except where alignment keys or the like are provided on one of the shells for engaging corresponding recesses or keyways provided on the mating shell.

As mentioned, the spring fingers 46 are located in an overlapping axial position relative the annularly shaped portion or split ring 42 and each is suspended from the front axial end of the split ring by a folded back or U shaped portion 48. The spring fingers 46 each have a concave radially bowed out section 50 intermediate the folded back portion 48 and the free ends 52 of each spring finger for engaging against the internal surface of connector shell 18. When the internal surface of shell 18 engages each concave section or portion 50, it of course applies radially inward pressure to the concave section 50 for forcing the juncture of the free cantilever end portion 52 with section 50 firmly against the shell 12.

The rear or other axial end or edge of the annularly shaped portion 42 has an integrally formed radially outwardly extending lip 54 which engages behind a radially outwardly extending shoulder 56 formed on the internal surface of the connector shell 12 and spaced axially rearwardly of the front end of shell 12. As men tioned previously, the split or annularly shaped ring 40 has an axially extending split or passageway 44 therein that extends through the lip 54. The split 44 in the lip receives a key 58 extending axially rearwardly from the shoulder 56 on the internal surface of shell 12.

Key 58 projects axially of the shell 12 from shoulder 56 to fit the passageway in the lip 54 or between the end segments of the lip for polarizing or correctly aligning the grounding spring fingers 46 with the shells or the keys or lugs 59 on shell 12 and preventing rotational movement therebetween. The key 58 is also received in a keyway of the dielectric insert assembly 24 so that it also serves to properly align the dielectric insert assembly and contacts with the shell. The dielectric insert assembly, it will be noted, has a radially outwardly extending shoulder 60 thereon for abutting engagement with the rear annular surface of lip 54 so that the lip is nestingly and securely received between the

shoulders

56 and 60. The dielectric insert assembly 24 also has a reduced outer peripheral portion which fits into the front end of shell 12 to engage the inner periphery of the annularly shaped portion 42, which is therefore also nestingly received and protected by the adjacent internal surface of shell 12 and the outer surface of the assembly 24.

The fingers 46 are substantially /32 inch long and 0.04 inch wide with a pitch of 0.06 inch, except where keys 59 are provided, the fingers are omitted. Lip 54 is substantially 0.025 inch high. The fingers and lip are formed on respective axial ends of the grounding spring 40 while the spring is flat or generally planar as shown in FIG. 4. It will be noted from FIG. 5 that the fingers normally extend radially outwardly of the portion 42 and the ends of the fingers attached to portion 42 are formed on a radius of substantially 0.015 inch. The spring, which comprises a resilient conductive metal, is

then formed into substantially a ring or an annular shape having an axial length of 0.433 inch for example, and a theoretical diameter of substantially 0.4 inch for a size 8 connector to 1.3 inches diameter for a size 24 connector. The spring thus has an unrestrained circumferential dimension larger than the circumferential dimension of the front end of shell 22 and corresponding to the shape of the front end 22 of shell 12. as shown in FIG. 6.

To assemble the grounding spring 40 to the shell 12, the front end 22 of the shell 12 is inserted between the free ends 52 and the fingers 46 and the annularly shaped portion 42. It will be noted that the free ends 52 extend radially outwardly to provide a funnel shaped guideway for the shell end and that the annular portion 42 is reduced circumferentially, as permitted by split or passageway 44 to facilitate entry of the lip 54 and the annular portion into shell 12. If the free ends 52 forming the guideway are omitted, the free ends of the fingers are simply spaced from portion 42 by a distance sufficient to allow entrance of the connector shell between the fingers and portion 42. In this latter case a distance of 3/32 inch including the wall thickness of the fingers and portion 42 is sufficient to enable receipt of the shell wall between the fingers and portion 42. The spring 40 is moved axially relative the shell 12 until the lip 54 is aligned with the key 58. In the relative axial movement between annular portion 42 and shell 12, the annular portion contracts, of course, only by a distance necessary to move portion 42 and lip 54 through the shell so that its deformation is automatically controlled by the thickness ofthe shell wall and thereby the basic shape and resiliency of the spring is retained.

Some of the pressure holding portion 42 reduced in circumference is relieved as the lip 54 is moved into axial registry behind shoulder 56, as the lip then expands to seat behind the shoulder 56. This shoulder, key and front end of the shell each therefore serves as a locating or retention means and the lip and passageway 44 each serve as securing means for securing the grounding spring on the shell. Thus the annular portion may engage one shell surface and the fingers overlap or be radially spaced adjacent the other shell surface to hold the spring in position. The dielectric insert assembly 24 is thereafter inserted in the shell to nestingly engage the spring 40 between the shell and insert assembly so that the spring is now retained in its proper position and protected. Thereafter, in response to engagement of shell 12 with shell 18, spring fingers 46 engage with the internal surface of shell 18 and are forced against the outer surface of shell 12 before the contacts of the shells engage to ensure grounding between the shells.

The foregoing constitutes a description of an improved grounding spring assembly whose inventive concepts are believed set forth in the accompanying claims.

What is claimed Is:

1. A grounding spring for use on a connector shell having a front end of annular shape and retention means on one surface of said shell, comprising;

an annularly shaped portion of resilient conductive material having an axially extending passageway therein for enabling engagement of said annularly shaped portion with said one surface of said connector shell;

a plurality of circumferentially spaced cantilever spring fingers formed at one axial end of said annularly shaped portion with said fingers arranged in folded back relationship to said portion and in radially spaced relationship to said portion for receiving the front end of said shell between said portion and said fingers;

and securing means on said annularly shaped portion for engagement with said retention means in response to the engagement of said annularly shaped portion with said one surface of said shell and the receipt of said front end between said portion and said fingers to hold said portion and fingers against axial movement relative said shell.

2. The grounding spring claimed in claim 1 in which said annularly shaped portion engages the internal surface of said shell and said securing means includes a radially outwardly extending annularly shaped lip formed at the other axial end of said portion with said lip having an axially extending passageway therein for engaging said retention means to hold said portion against rotational movement.

3. The grounding spring claimed in claim 2 in which said annularly shaped portion has an unrestrained circumferential dimension larger than circumferential dimension of said shell front end for tightly engaging said annular portion against the internal surface of said shell.

4. The grounding spring claimed in claim 3 in which each finger has a free end extending radially outwardly of said portion to form a guideway for receiving the front end of said shell between said fingers and said portion.

5. A combination with the grounding spring claimed in claim 2 in which said retention means comprises an axially extending key engaging one passageway.

6. A combination with the grounding spring claimed in claim 2 in which said retention means comprises a radially outwardly extending shoulder on the internal surface of said shell.

7. The grounding spring claimed in claim 1 in which said fingers each have a free end and a radially outwardly projecting concave section formed therein intermediate the free end of each finger and said one axial end of said portion.

8. The grounding spring claimed in claim 7 in which each finger free end extends radially outwardly of said' portion to form a guideway for receiving the front end of said shell between said fingers and said portion.

9. A grounding spring for use in a connector shell assembly including a first connector shell having a front end of annular shape adapted to telescopingly engage in the front end of a second connector shell having an annular shape with said first shell having a radially outwardly extending shoulder formed in the internal surface of said first shell spaced axially rearwardly of the front end of said first shell and a key on the internal surface of said first shell extending axially rearwardly from said shoulder to locate a dielectric insert assembly carrying a plurality of contacts in said first shell, the improvement comprising:

an annularly shaped portion of resilient conductive material corresponding in shape to the annular shape of the front end of said first shell and having an axially extending passageway therein for enabling reduction in the circumferential dimension of said annularly shaped portion for receipt in the front end of said first connector shell;

a plurality of circumferentially spaced cantilever spring fingers formed at the front axial end of said annularly shaped portion with said fingers arranged in folded back relationship to said portion and in overlapping radially outwardly spaced relationship to said portion for receiving the front end of said first shell between said portion and said fingers and with said fingers adapted to engage the internal periphery of the front end of the second shell in response to the telescoping engagement of the front end of said first shell in the front end of said second shell;

radially outwardly extending lip means formed at the other axial end of said annularly shaped portion and engaging the radially outwardly extending shoulder on the internal surface of said first shell between said shoulder and said dielectric insert assembly for preventing axial movement of said portion toward the front end of said first shell;

and passageway means in said lip means for receiving said key to prevent rotational movement of said portion and fingers relative said first shell.

10. The grounding spring claimed in claim 9 in which said fingers each have a radially outwardly extending concave section formed intermediate opposite ends of each finger for engaging the internal periphery of the second shell.

11. A grounding spring and connector shell assembly comprising;

a connector shell having an annularly shaped front end with a radially outwardly extending shoulder formed in the internal surface of said shell spaced rearward-1y of said front end and a key extending axially rearwardly of said shoulder;

an annularly shaped portion of resilient conductive material having an axial passageway therein extending between opposite axial ends of said portion for enabling reduction in the circumferential dimension of said portion for receipt in said front end;

a plurality of cantilever spring fingers formed at one axial end of said portion and folded back in overlapping radially outwardly spaced relationship to said portion for receiving front end of said shell between said fingers and said portion;

an annularly shaped radially outwardly extending lip formed at the other axial end of said portion and engaging said shoulder on the internal surface of said shell for preventing axial movement of said portion toward said front end;

and passageway means in said lip for receiving said key to hold said portion against rotational movement relative said shell.

12. The assembly claimed in claim 11, a dielectric insert for carrying a plurality of contacts with said dielectric insert having a radially outwardly extending shoulder for abutting engagement with said lip and an axially extending keyway for receiving said key.

13. The assembly claimed in claim 12in which said dielectric assembly has a peripheral surface portion engaging the intemal periphery of said annularly shaped portion.

Claims

1. A grounding spring for use on a connector shell having a front end of annular shape and retention means on one surface of said shell, comprising; an annularly shaped portion of resilient conductive material having an axially extending passageway therein for enabling engagement of said annularly shaped portion with said one surface of said connector shell; a plurality of circumferentially spaced cantilever spring fingers formed at one axial end of said annularly shaped portion with said fingers arranged in folded back relationship to said portion and in radially spaced relationship to said portion for receiving the front end of said shell between said portion and said fingers; and securing means on said annularly shaped portion for engagement with said retention means in response to the engagement of said annularly shaped portion with said one surface of said shell and the receipt of said front end between said portion and said fingers to hold said portion and fingers against axial movement relative said shell.

4. The grounding spring claimed in claim 3 in which each finger has a free end extending radially outwardly of said portion to form a guidway for receiving the front end of said shell between said fingers and said portion.

8. The grounding spring claimed in claim 7 in which each finger free end extends radially outwardly of said portion to form a guideway for receiving the front end of said shell between said fingers and said portion.

9. A grounding spring for use in a connector shell assembly including a first connector shell having a front end of annular shape adapted to telescopingly engage in the front end of a second connector shell having an annular shape with said first shell having a radially outwardly extending shoulder formed in the internal surface of said first shell spaced axially rearwardly of the front end of said first shell and a key on the internal surface of said first shell extending axially rearwardly from said shoulder to locate a dielectric insert assembly carrying a plurality of contacts in said first shell, the improvement comprising: an annularly shaped portion of resilient conductive material corresponding in shape to the annular shape of the front end of said first shell and having an axially extending passageway therein for enabling reduction in the circumferential dimension of said annularly shaped portion for receipt in the front end of said first connector shell; a plurality of circumferentially spaced cantilever spring fingerrs formed at the front axial end of said annularly shaped portion with said fingers arranged in folded back relationship to said portion and in overlapping radially outwardly spaced relationship to said portion for receiving the front end of said first shell between said portion and said fingers and with said fingers adapted to engage the internal periphery of the front end of the second shell in response to the telescoping engagement of the front end of said first shell in the front end of said second shell; radially outwardly extending lip means formed at the other axial end of said annularly shaped portion and engaging the radially outwardly extending shoulder on the internal surface of said first shell between said shoulder and said dielectric insert assembly for preventing axial movement of said portion toward the front end of said first shell; and passageway means in said lip means for receiving said key to prevent rotational movement of said portion and fingers relative said first shell.

11. A grounding spring and connector shell assembly comprising; a connector shell having an annularly shaped front end with a radially outwardly extending shoulder formed in the internal surface of said shell spaced rearwardly of said front end and a key extending axially rearwardly of said shoulder; an annularly shaped portion of resilient conductive material having an axial passageway therein extending between opposite axial ends of said portion for enabling reduction in the circumferential dimension of said portion for receipt in said front end; a pluralitY of cantilever spring fingers formed at one axial end of said portion and folded back in overlapping radially outwardly spaced relationship to said portion for receiving front end of said shell between said fingers and said portion; an annularly shaped radially outwardly extending lip formed at the other axial end of said portion and engaging said shoulder on the internal surface of said shell for preventing axial movement of said portion toward said front end; and passageway means in said lip for receiving said key to hold said portion against rotational movement relative said shell.

13. The assembly claimed in claim 12 in which said dielectric assembly has a peripheral surface portion engaging the internal periphery of said annularly shaped portion.