US3836947A

US3836947A - Electrical contact receptacle with helper spring

Info

Publication number: US3836947A
Application number: US00335263A
Authority: US
Inventors: M Yeager
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1973-02-23
Filing date: 1973-02-23
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17
Also published as: YU35692B; HK24779A; JPS49135191A; AR197855A1; NL167553C; AT342133B; ATA133674A; CA1004737A; AU6564174A; AU474450B2; ES423283A1; SE397233B; NL7402304A; FR2219536A1; DE2407063C2; DE2407063A1; IT1006307B; JPS5510104B2; CH562519A5; BE811411A

Abstract

The present invention relates to a female electrical receptacle for receiving and making electrical contact with a male electrical terminal. One side of the receptacle is in the form of a resilient leaf spring folded about a side margin thereof which is integral with the receptacle. The leaf spring resiliently engages against a male terminal received in the receptacle to make an electrical connection therewith. The receptacle is further provided with an elongated helper spring folded about a side margin thereof which is integral with the receptacle. The helper spring is shorter than the leaf spring and has a free end which overlies the leaf spring. Upon insertion of a male terminal into the receptacle, the male terminal will resiliently deflect the leaf spring contact against the helper spring. The helper spring thereby serves to stiffen the spring contact to provide a relatively high gripping pressure on the male terminals. The spring contact further is deflected by the male terminal into engagement with the helper spring along its folded edge margin which resists the tendency of the spring contact to unfold and further serves to limit the deflection of the leaf spring to prevent deformation thereof. The helper spring also distributes the stresses along a substantial length of the leaf spring to prevent deformation thereof due to overstressing. In a modification, the receptacle may be provided with a folded tab portion overlying the free end of the spring contact against which the free end of the contact will engage to limit the deflection thereof when a male terminal is received in the receptacle.

Description

United States Patent [191 Yeager Sept. 17, 1974 ELECTRICAL CONTACT RECEPTACLE WITH HELPER SPRING [75] Inventor:

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: Feb. 23, 1973 [21] Appl. No.2 335,263

Marvin Leo Yeager, Carlisle, Pa.

Primary Examiner-Joseph H. McGlynn Attorney, Agent, or FirmGerald K. Kita [5 7 ABSTRACT The present invention relates to a female electrical receptacle for receiving and making electrical contact with a male electrical terminal. One side of the receptacle is in the form of a resilient leaf spring folded about a side margin thereof which is integral with the receptacle. The leaf spring resiliently engages against a male terminal received in the receptacle to make an electrical connection therewith. The receptacle is further provided with an elongated helper spring folded about a side margin thereof which is integral with the receptacle. The helper spring is shorter than the leaf spring and has a free end which overlies the leaf spring. Upon insertion of a male terminal into the re ceptacle, the male terminal will resiliently deflect the leaf spring contact against the helper spring. The helper spring thereby serves to stiffen the spring contact to provide a relatively high gripping pressure on the male terminals. The spring contact further is deflected by the male terminal into engagement with the helper spring along its folded edge margin which resists the tendency of the spring contact to unfold and further serves to limit the deflection of the leaf spring to prevent deformation thereof. The helper spring also distributes the stresses along a substantial length of the leaf spring to prevent deformation thereof due to overstressing. In a modification, the re ceptacle may be provided with a folded tab portion overlying the free end of the spring contact against which the free end of the contact will engage to limit the deflection thereof when a male terminal is received in the receptacle.

6 Claims, Drawing Figures PAIENIEUSEP 1 11914 SHEET 1 [1F 2 PAIENIE sen mu SHEET 2 [IF 2 ELECTRICAL CONTACT RECEPTACLE WITH HELPER SPRING The present invention relates generally to an electrical receptacle for making an electrical connection to a male electrical terminal received therein. In a specific form of the present invention, the receptacle is of box configuration having an open end for receiving the male terminal. One sidewall of the receptacle is formed by folding into an elongated resilient leaf spring contact which is resiliently preloaded into compression against a sidewall of the receptacle. When a male terminal is inserted into the receptacle, it will engage the leaf spring and overcome the preload thereof. When the preload is overcome, the leaf spring contact will be resiliently deflected by further insertion of the terminal, to store additional spring energy in the spring contact. The resilient energy will bias the spring contact into gripping relationship on the terminal. [t is generally known that a stiffer spring contact will produce a greater gripping pressure on the male terminal which improves the electrical connection therewith and also impedes the unwarranted separation of the male terminal from the receptacle. According to a feature of the present invention. the spring contact is readily deflected upon initial insertion of a maleterminal within the receptacle. However to enable such deflection of the spring contact, yet at the same time improve the gripping force of the contact spring against the male terminal, a helper spring is provided to overlie the spring contact. The helper spring is folded about a side margin thereof which is integral with the receptacle. As the male terminal continues to be inserted, the male terminalis forced to deflect both the spring contact and the helper spring in resilient spring action. The spring energy stored in the helper spring thus reacts against the spring contact and increases the gripping pressure of the contact spring on the male terminal to improve the electrical and mechanical connection and to prevent inadvertent withdrawal or separation of the male terminal from the receptacle.

The helper spring has an end which terminates over a medial portion of the spring contact. The spring contact will initially buckle resiliently over the end of the helper spring to transfer some of the spring deflection to the helper spring. Thus, the relatively weak spring contact will buckle resiliently without damage or excessive deflection. to enable transfer of deflection stresses to the helper spring and permit both spring contact and helper spring to deflect and contribute to the resilient gripping forces on the inserted terminal. When the terminal is substantially inserted, the leaf spring may be sufficiently deflected to where it is capable of being forced to engage and stop against the helper spring adjacent its side margin to resist and prevent unfolding of the spring contact when it is resiliently deflected by the male terminal. The spring contact is thereby protected against unfolding or deformation by excessive deflection thereof. This allows the receptacle to accept male terminals of a wide range of sizes without resultant deformation of the spring contact due to excessive deflection thereof. ln addition. the receptacle provides a contact with an effective variable spring rate, with relatively large allowable deflection and high spring characteristics without resorting to a material having varied thicknesses or a material which has inherent high spring properties.

The receptacle according to the present invention may be fabricated from a single piece of sheet metal, thereby eliminating the need for assembly of multiple parts. In addition a metal having relatively low spring properties may be utilized without resorting to a more expensive metal such as beryllium copper which is well known for its excellent spring properties.

Accordingly it is an object of the present invention to provide a one-piece resilient electrical receptacle for receiving and making electrical contact with a male electrical terminal, wherein the receptacle is fabricated with a leaf spring contact having a variable effective spring rate for gripping the male terminal.

It is another object of the present invention to provide an electrically conducting receptacle for receiving a male terminal, wherein the receptacle is provided with a resilient leaf spring contact for gripping and electrically engaging the male terminal, the spring contact being resiliently deflected by the terminal upon initial insertion thereof, and the receptacle being further provided with a helper spring in overlying relationship with the spring contact for increasing the resilient gripping pressure of the leaf spring on the male terminal Another object of the present invention is to provide an electrically conducting receptacle for receipt of a male electrical terminal, wherein the receptacle is of one-piece construction having a first leaf spring contact for resiliently gripping an inserted male terminal, together with a second helper spring overlying the leaf spring contact and acting to stiffen the leaf spring and increase its effective spring rate, to distribute stresses in the leaf spring contact along its length during its deflection, to provide an effective stop preventing excessive deflection of the spring contact and to prevent unfolding of the leaf spring contact.

Another object of the present invention is to provide an electrically conducting receptacle for receiving a male electrical terminal therein, wherein the receptacle is of one-piece construction having a channel portion defining sidewalls of the receptacle, and a cantilever spring portion folded about a side margin thereof which is integral with said channel portion, and a helper spring portion folded about its side margin which is also integral with the channel portion, the helper spring overlying the spring contact, to prevent unfolding of the spring contact, to provide a stiffener for the spring contact. to distribute along the length of the spring contact, to distribute along the length of the spring contact the stresses therein which are caused by deflection of the spring contact by insertion of the male contact within the receptacle, and to provide a positive stop against which the spring contact engages to prevent excessive deflection of the spring contact.

Another object of the present invention is to provide an electrically conducting receptacle for receiving and making an electrical connection to a male electrical terminal, the receptacle having a first resilient spring contact engaged and initially deflected upon insertion of the male contact, the spring contact resiliently engaging the male contact and providing an initial relatively low friction force resisting initial insertion of the male contact within the receptacle, the receptacle further being provided with a helper spring which is engaged by the spring contact and which effectively stiffens the spring contact and provides an increased resilient gripping force of the spring contact on the male electrical terminal thereby improving the electrical contact on the gripped male terminal.

Another object of the present invention is to provide an electrically conducting receptacle for electrical connection with a male electrical terminal received therein, the receptacle including a leaf spring contact which resiliently engages the inserted male terminal, the spring contact being retained in an initial resiliently deflected position and thus preloaded against at least one sidewall of the receptacle and being further deflected resiliently upon the insertion of a male electrical terminal within the receptacle, the initial deflection and the additional deflection storing spring energy providing a gripping pressure of the leaf spring contact against the inserted male terminal to provide an electrical as well as mechanical contact between the male terminal and leaf spring contact.

Other objects and many attendant advantages of the present invention will become apparent upon perusal of the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an enlarged fragmentary perspective of one preferred embodiment of an electrically conducting female receptacle according to the present invention together with a fragmentary exemplary male terminal for insertion into the preferred embodiment;

FIG. 2 is an enlarged elevation of the preferred embodiment illustrated in FIG. 1 with the exemplary male terminal about to be inserted into the receptacle;

FIG. 3 is an enlarged elevation of the preferred embodiment as shown in FIG. 1 with the male terminal being inserted into the preferred embodiment and with parts of the preferred embodiment broken away and with parts in section to illustrate the details thereof;

FIG. 4 is an enlarged plan of a sheet metal blank stamped in the one-piece configuration of the preferred embodiment and prior to forming the blank into the receptacle shape;

FIG. 5 is an enlarged perspective of another preferred embodiment according to the present invention;

FIG. 6 is an enlarged elevation of the preferred embodiment as shown in FIG. 5 illustrating an exemplary male terminal for insertion in the preferred embodiment as shown in FIG. 5;

FIG. 7 is an enlarged elevation of the preferred embodiment shown in FIG. 5 together with an exemplary male electrical terminal inserted therein and with parts of the preferred embodiment broken away and with other parts in section to illustrate the details thereof; and

FIG. 8 is a stamped metal blank illustrating the onepiece outline of the preferred embodiment as shown in FIG. 5.

With more particular reference to the drawings there is illustrated generally in FIG. 1 a preferred embodiment of an electrically conducting female receptacle type contact being generally of box configuration provided with an open end generally illustrated at 2 for receiving therein a male electrical terminal, an exemplary one of which is illustrated at 4. As shown the terminal is of elongated post configuration generally rectangular in cross section and provided with a tapered nose 6. However the male terminal may comprise any desired configuration. As shown in FIG. 4 the receptacle 1 may be fabricated from a single blank 8 of stamped metal. The blank includes a first portion 10 folded generally about the

bend lines

12 and 14 to form generally a channel portion which is U-shaped in cross section and provided with a bottom wall 16 and two sidewalls l8 and 20. The receptacle 1 is further provided with an elongated electrically conducting leaf spring contact portion 22 having a free terminal end 24, a first side margin 26 and an opposed side margin 28. At least a portion of the side margin 26 is integral with the channel shaped portion with an extending arm portion 30 integrally joining the side margin 26 along the fold line 32 with the channel portion.

As more particularly shown in FIGS. 1 4, the leaf spring contact 22 is folded about the side margin 26 and along a fold line 32, which defines at least a portion of the side margin 26, to a position generally overlying the channel portion. It is noted that the side margin 28 has an outwardly projecting stepped portion 34 making the contact 22 wider at a location opposite the fold line 32. As shown in FIG. 1 the stepped portion 34 of the side margin 28 is stopped against a projecting flange portion 36 which extends or projects from the sidewall 18. In addition, the stepped portion 34 engages against the lower or recessed edge margin 38 of the sidewall 18. Both the projection or projecting flange 36 and the recessed edge margin 38 are illustrated on the blank 8 in FIG. 4. The contact is preloaded against the

portions

36 and 38 of the sidewall 18. More specifically, the spring may be folded severly about the side margin 32 such that the stepped side margin 34 will be forcibly maintained in resilient compression against the

portions

36 and 38 of the sidewall 18 as described in order to prevent unfolding of the contact 22 about its folded edge margin portion 32.

With more particular reference to FIGS. 2 and 3, the elongated leaf spring contact 22 is reversely curved along its length. More specifically, a medial portion of the contact 22 is illustrated at 40 which is first curved generally at an incline to converge generally toward the bottom wall 16. The contact 22 is of a relatively narrow dimension between its

side margins

26 and 28 so it will project generally into the channel portion between the

opposed sidewalls

18 and 20 thereof. The free end 24 of the contact 22 is curved reversely with respect to the medial portion 40 to provide an outwardly flared tip immediately adjacent to the open end or opening 2 of the receptacle 1. The outwardly flared end 24 provides a flared or funnel configuration entry to facilitate insertion of the tapered nose 6 of the male contact 4. The reversely curved spring 22 has an arcuate surface portion 42 defining a narrow throat portion internally of the channel portion 10. In a similar fashion the bottomwall 16 may be optionally provided with a dimpled or recessed portion 44 opposite the spring contact portion 42 to define further the relatively narrow throad portion internally of the receptacle adjacent to the funnel entry provided by the outwardly flared end 24 of the spring contact.

As a further feature of the present invention, reference will be made more particularly to FIGS. 1 and 4, wherein there is illustrated an elongated helper spring portion 46 generally of tapered configuration and terminating in a free end 48 pointed away from the funnel entry and rearwardly of the receptacle. The helper spring 46 includes a side edge margin 50 integral with the sidewall portion 18 of the channel portion 10. The helper spring 46 is folded about its side edge margin 50 along a fold line 52 such that the spring 46 is folded into overlying relationship over the contact spring 22. Accordingly, the helper spring 46 is integral with one sidewall 18 of the channel portion 10, while the contact spring 22 is folded about its edge margin 32 integral with the opposite sidewall 20 of the channel portion 10.

As shown in the drawings, the receptacle 1 includes an integral pair of clamping

flanges

54 and 56 which are formed into opposed sidewall portions as shown in FIG. 1. Additionally the blank 8 is formed with an additional opposed pair of

opposed flanges

58 and 60 which are formed into a U-shape as shown in FIG. 1. For example, the

opposed flanges

54 and 56 may be curled toward one another to form a crimped barrel connection to a wire conductor (not shown), while the

opposed flanges

60 and 58 may likewise be curled toward each other to provide a crimped barrel type connection to the insulation of the wire conductor (not shown). In this manner the receptacle 1 may be secured electrically and mechanically to an electrically conducting insulation covered wire in the well known manner as taught in US. Pat. No. 2,791,755. The opposed pairs of

flanges

54, 56 and 58, 60 may be substituted with any other type of electrical connecting configuration which may be made integral with the blank 8 to make any desired other types of electrical connections.

In operation of the preferred embodiment, reference will be made to FIGS. 2 and 3. The outwardly flared spring end 24 cooperates with the bottomwall 16 of the receptacle to provide a funnel entry to facilitate the insertion of the nose portion 6 of a male terminal 4. As the terminal 4 is initially inserted into the funnel entry. the terminal 4 will be initially inserted into the relatively narrow throat area and thereby engage both the spring portion 42 and the dimple portion 44 of the bottom wall 16. Initially, the terminal will overcome the preload energy of the spring contact as the tapered nose 2 is inserted into the reduced throat area. Additional insertion of the terminal will cause a thicker portion of the terminal to enter the reduced throat area and resiliently deflect the spring 22 outwardly of the receptacle in cantilever fashion. Such action causes resilient spring energy to be stored in the spring contact 22 which acts to bias the spring contact 22 into gripping engagement on the terminal 4. However, the spring contact 22 is specifically designed to be deflected upon initial insertion of the terminal 4. Upon further insertion of the terminal 4 the spring contact portion 42 will be slidable along the terminal 4 as it is inserted. Even though the spring contact 22 is deflected, the friction caused by sliding along the terminal will only moderately resist such further insertion ofthe terminal 4. As shown more particularly in FIG. 3 the spring contact 22 is in engagement against the free end 48 of the helper spring 46. As shown the free end 48 of the helper spring terminates at the medial portion 40 of the contact spring 22. The elongated helper spring 46 is thus shorter in length than that of the contact spring 22 which it overlies. Such engagement of the medial portion 40 of the spring contact 22 against the free end 48 of the helper spring 46 causes the spring contact to bend resiliently without damage or excessive deflection over the end 48 of the helper spring. This transfers some of the bending loads to the helper spring, causing both the spring contact and the helper spring to deflect resiliently together over a wide range of deflection. The spring contact and helper spring are not fastened to each other and are therefore deflected over a wider range than would be possible for a larger, stiffer spring having very little deflection. Thus, a broad range of terminal sizes may be accepted by the present invention merely by the wide range of deflection of the spring contact and helper spring. A receptacle having a stiff spring, although providing comparable resilient gripping pressure, would not have a wide range of deflection before excessive deflection and bending of the spring would occur.

The initial insertion of the terminal must overcome the preload in the spring contact. Thus, as the terminal is inserted and as it overcomes the preload, the follow ing occurs. The gripping force on the terminal increases rapidly and very littly" or practically no deflection of the spring contact will occur until its preload is overcome. When the preload is overcome, then resilient deflection of the spring contact is allowed to occur, with the resilient gripping force increasing much less rapidly and occurring over a relatively wide range of deflection in the spring contact and helper spring.

The primary purpose of the preload is to keep the forward end of the spring contact stopped in a wide open position against the margin portion 34, rather than freely oscillating in cantilever fashion which might stub against the terminal as it is inserted. It also reduces the insertion force because the funnel entry is forced wide open when it first receives the terminal. The helper spring thus resiliently deflects together with the spring contact 22 and thereby increases the effective spring rate of the spring contact 22, forcing the spring contact 22 to provide a larger gripping pressure against the terminal 4 than would be available by the contact 22 without the helper spring 46. The increased gripping pressure therefore is provided by the resilient spring energy stored in both

springs

22 and 46, and is applied at the portion 42 of the contact spring 22 at the relatively narrowed throat area of the receptacle. Such increased gripping pressure improves the electrical contact between the spring contact 22 of the receptacle 1 and the male terminal 4. As well, the increased mechanical gripping pressure prevents inadvertent removal of the male terminal 4 from the receptacle.

The helper spring 46 performs additional functions in addition to increasing the effective spring rate of the spring contact 22 subsequent to initial insertion of the male terminal 4. Immediately upon engagement of the contact 22 against the helper spring 46, the stresses of the contact spring 22 which are caused by the resilient deflection thereof by the male terminal 4 are distributed along its points of contact with the helper spring 46. This prevents bending or deformation of the spring contact 22 which might be caused by the concentration of rather than the distribution of such stresses. In addition, it often occurs that the male terminals 4 of different sizes are inserted into the receptacle 1. If the receptacle is forced to receive a terminal of relatively large size, the spring contact 22 will be deflected by the terminal into engagement against the helper spring until the helper spring energy resists further deflection of either spring 22 or spring 46. Thus a stop is provided to limit further deflection of the contact spring 22, thereby protecting the contact spring from deformation caused by excessive deflection thereof. In addition, it has been observed that the described resilient deflection of the contact spring 22 by the insertion of a male terminal 4 will tend to unfold the contact spring 22 about its side edge margin 32. However, the helper spring 46 will prevent such tendency of the spring contact to unfold because the free side margin 34 of the contact 22 must first engage the spring contact 46 adjacent to its folded edge margin 52, and thereby force the helper spring 46 to unfold. But since the engagement between the spring contact 22 and the helper spring 46 is adjacent to the edge margin 52 there is insufficient leverage to force the helper spring to unfold. Accordingly, the helper spring folded margin resists the tendency of the spring contact 22 to unfold. The receptacle is provided with an optional tine portion 62 which may be used to lock the terminal within a housing cav ity (not shown).

FIGS. 8 illustrate another preferred embodiment of the receptacle 1 according to the present invention. Duplicate numerals indicate like parts with the exception of the addition of primed designations to distinguish between the two embodiments. Accordingly, the embodiment 1 includes a metal blank 8 having a portion 10' which is formed into a channel shape by folding along the fold lines 12 and 14. The channel portion includes a bottomwall portion 16' provided with a dimpled portion or recessed portion 44 and a pair of integral sidewall portions 18' and 20'. The wall 20 includes a tine portion 62'. The receptacle 1' includes a cantilever leaf spring contact 22' folded about its edge margin 32' to form another wall of the receptacle. The medial portion 40' of the spring contact is bent with a reverse curved portion to first enter into or converge toward the channel shaped portion and then diverge away from the channel shaped portion by a reverse curvature in the end 24' of the spring contact. A narrow throat area is thereby defined between the portion 42' of the spring contact 22' and the optional dimpled portion 44' of the bottomwall portion 16'. A stepped portion 34' in the form of a tab forms a part of the side margin 28. The spring contact is resiliently deflected into preloaded condition in resilient compression on the sidewall 38'. A helper spring portion 46' is folded about its side margin 52' which is integral with the channel shaped portion 10' so that the helper spring longitudinally overlies the contact spring 22'. The helper spring 46' differs from the helper spring 46 in that it is elongated with its free end 48' generally to ward the receptacle opening 2' and generally adjacent to the free end 24' of the spring contact 22'. However, the helper spring 46 performs the same function as the helper spring 46. More specifically, as the male terminal 4 is initially inserted within the receptacle the preload of the spring contact 22' is overcome. As the terminal 4 is continued to be inserted in the receptacle, the spring contact 22' and the helper spring 46 will be deflected resiliently, with the helper spring serving to distribute stresses along the length ofthe spring contact 22 along the points of engagement with the spring contact. Additionally, the helper spring 46' serves to increase the effective spring rate of the spring contact 22' by forcing the male terminal to resiliently deflect both the spring contact as well as the helper spring upon such further insertion of the male terminal within the receptacle. Also the helper spring provides a stop to prevent excessive deflection of the spring contact 22' and to prevent the tendency of the spring contact 22' to unfold. More specifically, the free side margin 28' of the spring contact will engage against the helper spring 46 adjacent to its folded side margin 52'. The

leverage of the free side margin 28 will be insufficient to cause the helper spring 46' to unfold. Accordingly the helper spring resists the tendency of the spring contact 22 to unfold.

The preferred embodiment l differs from the previous embodiment in that an additional tab or flap portion 62 is provided folded about its side margin 64 integral with the sidewall portion 18' of the channel shaped portion 10. The tab is folded so as to overlie the free end 24' of the spring contact 22'. The tab 62 provides a permanent stop against which the end 24' will engage when the spring contact 22 is resiliently deflected to a maximum controlled amount. This permits the receptacle to accept male terminals 4 having a variety of sizes, with the tab 62 assisting the helper spring to prevent excessive deformation and deflection of the spring contact 22.

What has been described is an electrically conducting receptacle for making a mechanical and electrical connection with an elongated male electrical terminal. In each embodiment the leaf spring contact is a cantilever beam which is curved to project somewhat into the receptacle and provide a relatively narrow throat portion of the receptacle in which the male contact is inserted and gripped. The leaf spring contact is preloaded, or more specifically, is maintained in a resiliently deflected condition in engagement with a sidewall of the receptacle. This is accomplished by forming or bending the spring contact to project initially inwardly into the receptacle. Subsequently as the receptacle is folded into the channel configuration, the spring contact will engage on one of the sidewalls of the channel portion 10 and will be deflected resiliently outward of the channel portion 10, thereby storing resilient spring energy.

In each version, the spring contact is integral with the receptacle and operates like a cantilever beam in resilient deflection upon initial insertion of a male terminal into the receptacle. It is desirable to stiffen the spring contact in order to provide a firm resilient grip on the male contact when fully inserted into the receptacle. It is also desirable to provide a stop means against which spring contact will engage in order to limit the deflection of the spring contact. This is accomplished by a helper spring which is an integral part of the receptacle and which is folded along a side margin thereof to overlie longitudinally the spring contact. To insert the male terminal, the terminal is forced to resiliently deflect both the spring contact and the helper spring thereby increasing the gripping force of the spring contact on the male terminal which improves both the mechanical and electrical connection. Scraping or sliding between the male terminal and the contact spring occurs as the terminal is inserted so as to clean the contact surfaces therebetween which further improves the electrical connection.

The spring contact and the helper spring are folded from opposite sides ofthe channel portion of the receptacle. Since the spring contact is resiliently deflected by the male terminal it will tend to unfold during deflection about its folded side margin. However, since the helper spring is folded about a side margin on an opposite side of the receptacle, the folded margin of the helper spring is adjacent to the unfolded side edge of the spring contact. The unfolded side edge of the spring contact will engage the helper spring adjacent its folded side margin. There is insufficient leverage of the unfolded side edge of the spring contact to unfold the helper spring. Thus the helper spring acts to prevent the tendency for the spring contact to unfold during deflection. Accordingly the helper spring of each embodiment acts as a stiffener for the associated spring contact and increases its effective spring rate properties. The helper spring of each embodiment also distributes the stresses of the spring contact caused by its deflection along the length of the spring contact where it engages against the helper spring. The helper spring of each embodiment further provides a positive stop to prevent unfolding and excessive deflection of the spring contact upon insertion of a male terminal within the receptacle. The use of the helper spring thereby provides a receptacle having a spring contact with an effective variable spring rate, the helper spring of each embodiment also permits a relatively high effective spring rate over a wide range of resilient deflection, even though the material has relatively low spring properties, without resorting to a material having desirably high spring properties.

In a modification of the present invention the helper spring may be provided with an auxiliary stop in the form of an additional flap adjacent to the free end of the spring contact to prevent excessive deformation of the spring contact.

What has been described are preferred embodiments of the present invention. It is to be understood that other embodiments and modifications of the present invention which will be apparent to one having ordinary skill in the art are to be covered by the spirit and scope of the appended claims, wherein:

What is claimed is:

1. An electrically conducting receptacle having an open end for receiving a male electrical terminal therein comprising: a generally channel shaped portion defining sidewalls of said receptacle, a cantilever spring contact portion having a free end and a free side margin and another side margin joined integrally with said channel portion, said spring contact portion being folded about its said another side margin to form an elongated, electrically conducting spring contact defining a resilient sidewall of said receptacle, said spring contact having an outwardly flared end portion to define a funnel entry adjacent said open end of said receptacle, said spring contact being curved along its longitudinal dimension to project generally internally of said channel portion to define a reduced throat area internally of said channel portion, said spring contact being resiliently deflected when a male contact is initially received in said reduced throat area, a helper spring having a side margin thereof integral with said channle poriton, said helper spring being folded along said side margin to overlie said spring contact, said helper spring having a free, end thereof terminating adjacent a medial portion of said spring contact, with said spring contact being resiliently deflected into engagement against said helper spring upon insertion of a male terminal within said receptacle, said helper spring having its folded side margin adjacent to said free side margin of said spring contact such that the free side margin of said contact will engage and stop against said helper spring adjacent to its folded side margin and thereby prevent the tendency of said spring contact to unfold upon the resilient deflection thereof.

2. The structure as recited in claim 1, wherein, said helper spring is elongated with its free end extending toward the free end of said spring contact, and further including: a flap portion folded along an integral side margin thereof with said side margin of said flap portion being adjacent said free end of said spring contact whereby said free end of said spring contact engages and stops against said flap portion upon the resilient deflection of said spring contact.

3. The structure as recited in claim 1, wherein, said helper spring has its folded side margin adjacent the free end of said spring, whereby, upon deflection of said spring contact, said free end of said spring contact will engage and stop against said helper spring adjacent its folded side margin to prevent unfolding of said spring contact and to prevent excessive deflection of said spring contact.

4. An electrically conducting receptacle adapted to receive a male terminal therein, said receptacle being formed by a folded metal blank comprising:

An elongated channel-shaped portion folded from said metal blank and having first and second side portions,

A first resilient contact spring forming a third side portion of said receptacle, said contact spring being folded on a side margin thereof which is connected integrally with said first side portion of said receptacle,

And a helper spring being folded on a side margin thereof which is connected integrally with said second side portion of said receptacle,

Said contact spring having a free end protruding outwardly from said helper spring and being located adjacent an open end of said elongated channelshaped portion,

Said'helper spring being shorter than said contact spring and having a free end projecting longitudinally in overlying relationship with respect to said contact spring, said free end of said helper spring being engagable on said contact spring upon resilient deflection of said contact spring toward said helper spring,

Said contact spring being initially deflected by receipt of a male terminal into said receptacle, and said helper spring being deflected together with said contact spring upon further insertion of said male terminal into said receptacle, thereby providing a receptacle with an effective spring rate which is variable.

5. The structure as recited in claim 4, wherein, said helper spring is elongated with its free end extending toward the free end of said contact spring, and further including:

A flap portion folded along an integral side margin thereof which is connected to said second side portion of said receptacle, said side margin of said flap portion being adjacent said free end of said contact spring, whereby said free end of said contact spring engages and stops against said flap portion adjacent the side margin thereof upon resilient deflection of said contact spring.

6. The structure as recited in claim 4, wherein, said helper spring has its folded side margin adjacent the free end of said contact spring, whereby upon deflection of said contact spring, said free end of said contact spring engages and stops against said helper spring adjacent its folded side margin to prevent unfolding of said contact spring and to prevent excessive deflection of said contact spring.

Claims

1. An electrically conducting receptacle having an open end for receiving a male electrical terminal therein comprising: a generally channel shaped portion defining sidewalls of said receptacle, a cantilever spring contact portion having a free end and a free side margin and another side margin joined integrally with said channel portion, said spring contact portion being folded about its said another side margin to form an elongated, electrically conducting spring contact defining a resilient sidewall of said receptacle, said spring contact having an outwardly flared end portion to define a funnel entry adjacent said open end of said receptacle, said spring contact being curved along its longitudinal dimension to project generally internally of said channel portion to define a reduced throat area internally of said channel portion, said spring contact being resiliently deflected when a male contact is initially received in said reduced throat area, a helper spring having a side margin thereof integral with said channle poriton, said helper spring being folded along said side margin to overlie said spring contact, said helper spring having a free end thereof terminating adjacent a medial portion of said spring contact, with said spring contact being resiliently deflected into engagement against said helper spring upon insertion of a male terminal within said receptacle, said helper spring having its folded side margin adjacent to said free side margin of said spring contact such that the free side margin of said contact will engage and stop against said helper spring adjacent to its folded side margin and thereby prevent the tendency of said spring contact to unfold upon the resilient deflection thereof.

4. An electrically conducting receptacle adapted to receive a male terminal therein, said receptacle being formed by a folded metal blank comprising: An elongated channel-shaped portion folded from said metal blank and having first and second side portions, A first resilient contact spring forming a third side portion of said receptacle, said contact spring being folded on a side margin thereof which is connected integrally with said first side portion of said receptacle, And a helper spring being folded on a side margin thereof which is connected integrally with said second side portion of said receptacle, Said contact spring having a free end protruding outwardly from said helper spring and being located adjacent an open end of said elongated channel-shaped portion, Said helper spring being shorter than said contact spring and having a free end projecting longitudinally in overlying relationship with respect to said contact spring, said free end of said helper spring being engagable on said contact spring Upon resilient deflection of said contact spring toward said helper spring, Said contact spring being initially deflected by receipt of a male terminal into said receptacle, and said helper spring being deflected together with said contact spring upon further insertion of said male terminal into said receptacle, thereby providing a receptacle with an effective spring rate which is variable.

5. The structure as recited in claim 4, wherein, said helper spring is elongated with its free end extending toward the free end of said contact spring, and further including: A flap portion folded along an integral side margin thereof which is connected to said second side portion of said receptacle, said side margin of said flap portion being adjacent said free end of said contact spring, whereby said free end of said contact spring engages and stops against said flap portion adjacent the side margin thereof upon resilient deflection of said contact spring.