US3641483A

US3641483A - Sockets for prong socket electrical contacts and in their methods of manufacture

Info

Publication number: US3641483A
Application number: US51773A
Authority: US
Inventors: Francois Robert Bonhomme
Original assignee: Connectronics Corp
Current assignee: Connectronics Corp
Priority date: 1969-07-04
Filing date: 1970-07-02
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: DE2033071A1; FR2052019A5; GB1311116A

Abstract

The socket comprises a portion cut out into contact strips by longitudinal slots and has, over at least a fraction of its length comprising the portion cut into strips, a cross section internally limited by a closed continuous curve and externally by a polygonal closed line. The longitudinal slots are closed at their longitudinal ends and pass through the vertices of the polygonal closed line. The strips are concave in axial direction. The socket ensures good electrical contact even after numerous insertions and extractions.

Description

United States Patent Bonhomme 1 Feb. 8, 1972 [54] SOCKETS FOR PRONG SOCKET ELECTRICAL CONTACTS AND IN THEIR METHODS OF MANUFACTURE [72] Inventor: Francois Robert Bonhomme, Saint-Cloud,

France [73] Assignee: Connectronics Corporation, New York,

[221 Filed: July 2,1910

21 Appl.No.i 51,773

{30] Foreign Application Priority Data July 4, 1969 France ..6922890 [52] US. Cl. ..339/217 S, 339/258 A [51] Int, Cl. ..H0lr9/12,I-I0lr 11/22 [58] Edd oISearch ..339/217, 256, 258, 252, 176; 29/129,130 A; 287/126; 24/115 H, 155 R, 155 D,

155 BB, 201 S, 158, 230 R, 230 SL, 257

[56] References Cited UNITED STATES eATsN'rs 3,396,364 8/1968 Bonhomme .Q .339/217 FOREIGN PATENTS OR APPLICATIONS 1,479,600 3/1967 France ..339/ 258 927,342 5/ 1 955 Germany 339/256 993,316 5/1965 Great Britain ....339/256 1 14,988 8/1925 Switzerland ..339/25 8 A Primary ExaminerMarvin A. Champion Assistant Examiner-Robert A. Hafer Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT The socket comprises a portion cut out into contact strips by longitudinal slots and has, over at least a fraction of its length comprising the portion cut into strips, a cross section internally limited by a closed continuous curve and externally by a polygonal closed line. The longitudinal slots are closed at their longitudinal ends and pass through the vertices of the polygonal closed line. The strips are concave in axial direction. The socket ensures good electrical contact even after numerous insertions and extractions.

10 Claims, 10 Drawing figures PMENFEBFm 8 m2 SHEET 1 UF 4 PAIENTEBFEB 81912 3.641.483

SHEET 3 (IF 4 SOCKETS FOR PRONG SOCKET ELECTRICAL CONTACTS AND IN THEIR METHODS OF MANUFACTURE v The invention relates to sockets, for prong and socket electrical contacts, of the type which comprises a portion cut out into contact strips by longitudinal slots and which, over at least a fraction of their length comprising the above-said portion cut out into strips, have a transverse section limited internally by a continuous closed curve and, externally, by a polygonal closed line inscribed in a curve parallel to the first.

Sockets of this type are already known and give satisfactory results. However, the quality of the electrical contact ensured by such sockets, especially afier numerous insertions and extractions, can be further improved.

It is a particular object of the invention, to render the sockets such that they ensure good electrical contact, even after numerous insertions and extractions.

According to the invention, a prong and socket electrical contact socket of the type concerned is characterized by the fact that, on one hand, the longitudinal slots are closed at their longitudinal ends and pass through the vertices of the polygonal closed line and that, on the other hand, the strips of the above-said portion are concave in axial direction and are adapted to be deformed on uniting the socket with a prong.

Advantageously, when the socket is intended to be mounted in a housing provided in an insulating support, one of the strips at least is cut out by a transversal slot extending between two neighboring longitudinal slots, into two tongues arranged head to tail with respect to one another and the tongues fonned by the one or more transversely cut out strips separate inwardly so as to project by their free ends on the outer surface of the socket and to be able to cooperate with a locking boss provided in the above-said housing.

The invention also relates to a method of manufacturing a socket such as defined above.

This method is characterized by the fact that it commences with a prismatic solid body of polygonal cross section, that grooves are fashioned over a fraction of the length of the crests of the outer surface, that a longitudinal cavity is pierced in the body whose transverse section has dimensions such that the above-said grooves open into the cavity and constitute the slots dividing the intermediate portion of the socket into strips and that the intermediate portion of the body is then subjected to a permanent mechanical deformation adapted to give the strips their axial concavity.

The invention consists, apart from the features mentioned above, in certain other features which are preferably used at the same time and which will be more explicitly considered below with regard to preferred embodiments of the invention which will now be described in more detailed manner with reference to the accompanying drawings but which are in no way limiting.

FIG. 1 of the drawings shows, in perspective, a socket constructed according to the invention and the end of a prong corresponding to the socket.

FIG. 2 shows partly in cross section at the level of its intermediate portion, and partly in end view, the embodiment of the socket of FIG. 1.

FIG. 3 is a partial section along the line III-III of the FIG. 2.

FIG. 4 shows, in perspective, another type of socket constructed according to the invention.

FIGS. 5 and 6 show in cross section a socket at difi'erent stages of manufacture.

FIG. 7 shows, in perspective, another embodiment of a socket according to the invention which is a variation of that shown in FIG. 1.

FIG. 8 shows the embodiment of FIG. 7 mounted in an insulating support.

FIG. 9 shows one of the phases of the method of manufacturing the embodiment of the FIG. 7, in the case of manual execution.

Lastly, FIG. 10 shows the same phase of the method of manufacture as FIG. 9, but in the case of execution on an automatic machine.

Referring to FIG. 1, there can be seen a socket l of rectilinear tubular shape, having a longitudinal cavity 2 intended to receive a cylindrical prong 3.

The socket 1 includes a'concave intermediate portion 4 (in the direction parallel to the axis of insertion) whose internal cross section, in resting position, has dimensions and a surface less than those of the cross section of the prong 3. At one end, the socket 1 can include a cylindrical tail T for connecting to an electrical conductor.

When the prong 3 is introduced into the cavity 2, the intermediate portion 4 must then be deformed to enable the prong to pass. By reason of this deformation and, in consequence of the elasticity of this intermediate portion of the socket l, the inner surface 5 of the said intermediate portion constitutes a contact surface which will exert pressure on the prong 3, which contributes to establishing good electrical contact between the said prong and socket.

The socket 1 has, at least over a fraction 6 of its length comprising the said intermediate portion 4, a cross section limited internally by a closed continuous curve 7 corresponding to the section of the contact surface 5 or of its extension 8 and, externally, by a polygonal closed line 9 inscribed in a curve I0 parallel to the first curve 7.

The intermediate portion 4 is cut out into strips 11 by longitudinal slits l2 closed at their ends 13 and passing through the apices 14 of the polygonal closed line 9.

The continuous curve 7 is generally constituted by a circumference and forms an inner geometrical limit of the transverse section of the socket. As can be seen in FIG. 2, at the right of the slits 12, the curve 7, shown in mixed line and displaced radially towards the inside to facilitate the reading of the drawing, is extended in imaginary manner while in reality the inner contour of the section is formed by a series of arcs of the curve 7 separated from one another by the slits 12.

The polygonal closed line 9 is, preferably, constituted by a hexagonal contour 15 which can be regular when the curve 7 is a circumference since the curve 10, parallel to the curve 7, is then constituted by a concentric circumference.

The contour 15 being hexagonal, the slits 12 are six in number, corresponding to the number of apices of the contour 15. These slits traverse the wall of the intermediate portion 4, which gives a good flexibility to the strips 11. The ratio of the length of the slits 12 to the diameter of the circumference constituting the curve 7 can vary within fairly wide limits, of the order of 2 to 12.

The elasticity of the intermediate portion 4 of such a socket is very good, even if the socket l is formed of brass, copper or aluminum, of which materials the coeficient of elasticity is low.

Thickness of the wall of the socket 1, between two slots 12 or between two apices 14 of the polygonal line 9 (see FIG. 2) diminishes, pases through a minimum, then increases to resume its value, which enables the portion 4, on extraction of a prong, to resume with precision its resting position after the deformation caused by the introduction of the said prong.

In addition, due to the fact that the slots 12 are closed at their two longitudinal ends 13, the strips 11 rejoin at the ends of the said slots 12. The strips 11 are hence, in a way, held, at each of their ends, by a belt which is opposed to the outward separation of the said strips 11 on the introduction of the prong 3 into the cavity 2. As a result there is very good electrical contact between the prong and the socket and the qualityv of this contact is maintained after numerous insertions and extractions.

In another embodiment shown in FIG. 4, the polygonal outer contour, denoted here by 9a, can be constituted by an equilateral triangle 16, the slots being three in number and passing through the vertices of the triangle. The other elements similar to those of FIGS. 1 to 3 bear the same reference numerals, followed, in FIG. 4, by the letter a.

To produce such a socket 1, the method may be as follows, purely by way of nonlinriting example.

Initially a solid body is taken, of prismatic outer surface, preferably of regular hexagonal crom section.

The slots 12 are machined by a milling along the fraction of the length of the crests of the surface of the body and to a certaindepthh, sothatthe crosssectionofthe body, inthe portion where the slots 12 have been milled, is as shown in FIG. 5, at this first stage of the manufacture of the socket l. The slots 12 are closed at their longitudinal ends.

Then there is pierced'in the axis of the body a longitudinal cylindrical hole of radius R (FIG. 6) such that the sum of this radiusRandthedepthhoftheslots l2isgreaterthanthe distancefromthecrestsoftheprismaticsolidtotheaxisof this solid. Under these conditions, the slots 12 will open into thehole whose contour is shown in mixed line in FIG. 5. This precaution of engaging the

tongues

21, 22 in the corresponding grooves 27. The socket 1b is driven into the housing 25 so that, along the orientation of the socket and along the end of the housing 25 through which the said socket has been introduced, the

tongues

21 or 22 arrive in contact with the bosses 28.

For example, if the tail T of the socket lb has been introduced first through the upper end (for FIG. 8) of the how ing 25, the driving in of the socket lb into the said housing is effected in the direction of the arrow F in this case, it is the tongues 22 which will arrive first in contact with the bosses 28.

' If an inserting force continues to be exerted on the socket lb,

operation of piercing enables thus to be eliminated the burrs I caused by the milling ofthe slots 12.

The cross section in the portion comprising the slots, at this stage of manufacture thesocket 1, is shown in FIG. 6,'by the contour in mixed line. The width ofthe slots 12 is then equal to L. v

Lastly, the portion comprising the slots is mechanically deformed in permanent manner by a constricting operation, so as to obtain the portion 4 which has a concavity in the longitudinal direction. The strips 11 are displaced, in the course of this deformation, radially inwardly, from the position in line of FIG. 6 to the position in continuous line of the sameFIG. Asaresultthereisareductionintheradiusofthe hole and, at the same time, a reduction of the width of the slots 12 which become equal to l, I being less than L.

In FIGS. 7 to 10, there is shown another embodiment 1 which is a variation lb of the socket l of FIG. 1. The elements of FIGS. 7 to 10 identical with elements already encountered are denoted by the same reference figures followed by the letterband will notbedescribed again.

One of the strips llb at least is cut out by a transverse slot extending between two neighboring longitudinal slots 12b so that two

tongues

21, 22, arranged head to tail with respect to one another, are formed from the strip 11b which has bee cut transversely.

The

tongues

21, 22 separate outwardly so as to project by their ends or free

transverse edges

23, 24, over the outer surface of the socket lb. The said tongues have a rectangular contour of which three sides are free, the fourth side being located at the junction of the tongue with the outer surface of the socket.

, Preferably, when the polygonal line 9b is a regular polygon with an even number of equal sides at least four in number, and especially in the case of a hexagon, two diametrically opposite strips llb are each cut into two

tongues

21, 22 by a transverse slit 20, as shown in the drawings.

In general, the slit 20 is arranged substantially midway along the longitudinal slots 12b.

By referring to FIG. 8, it is seen that the socket lb is intended to be mounted in a housing 25 provided in a insulating support 26. The housing 25 traverses the said support from one side to the other and opens on to two opposite surfaces of this latter. The said housing 25 is limited by a prismatic surface whose cross section is slightly greater than the section of the socket lb, the contour of the said cross section being parallel to that of a transverse section of the socket lb.

One or several longitudinal grooves 27 arranged to receive the one or more transversely cut strips 1 lb, are provided in the walls of the support 26 which bond the housing 25. The width of these strips is slightly greater than that of the

tongues

21, 22. Midway along each group 27, a boss 28 is provided. These bosses 28 are adapted to cooperate with the

tongues

21, 22 on the introduction of the socket lb into the housing 25, so as to ensure locking of the socket in the said support. The grooves 27 open at each end of the housing 25.

The mounting of the socket lb in the support 26 is effected in the following manner. The socket lb is introduced into the housing 25, through any end of the latter, by taking the the bosses 28 will cause the withdrawal of the tongues 22, which permits the socket 1b to continue to penetrate into the housing 25. As soon as the free edges 24 of the tongues 22 have cleared the bosses 28, the said tongues 22, by reason of their elasticity, are raised and resume the position that they had before coming into contact with the bosses 28. The dimension of the boxes 28 along the direction of the arrow F, is equal to the width of the transverse slot 20, i.e., to the distance, along the direction F, of the

free edges

23 and 24 of the

tongues

21, 22. Thus, at the instant when the tongues 22 areraised, afierclearingthebosses28,thefreeedges23ofthe tongues 21 come into contact with the surface of the said bosses opposite to that which is situated facing the free edges 24 of the tongues 22.

The cooperation of the

tongues

21, 22 and the bosses 28 ensure on one hand, the positioning of the socket lb in the housing 25, along the axis of the latter, and, on the other hand, the locking of the socket in the support.

In FIG. 8, the surfaces of the bosses 28 which come into contact with the

free edges

23, 24 of the tongues, are substantially right angles to the axis of the housing 25. In a variation of the embodiment, these surfaces could be inclined on the said axis so that the cross section of the bosses 28, instead of being rectangular as in FIG. -8, would be trapezoid, the small base being turned towards the axis of the housing 25 and being less than the width of the slot 20, while the large base of the section of the boss furthest spaced from the axis of the housing, would have a dimension greater than the width of the slot 20.

It is obvious that instead of introducing the socket lb through the upper end of the housing 25, it could be introduced through the lower end of the said housing along the arrow F the tongues 21 then coming first into contact with the bosses 28 and being withdrawn under the action ofthese latter to be raised again after their clearance.

To extract the socket lb from its support 26, it suffices, for example, by means of a tool with two arms, in the case considered, arranged to be introducable respectively into the two grooves 27, to withdraw the tongues 22 and to exert on the socket 1b a force in the direction of the arrow F, to extract the socket. Naturally, the tongues 21 could have been withdrawn by means of the above-said tool and a force exerted on the socket lb in the direction of the arrow F, to extract the said socket through the lower end of the housing 25.

To produce a socket 1b such as that previously described, the procedure is advantageously as follows.

As previously described, there is first taken a solid prismatic body with a polygonal cross section. Groves are machined over a fraction of the length of the crests of the outer surface, the said grooves being closed at their ends. The longitudinal cavity 2b is then bored into the body, the depth of the grooves and the dimensions of the cavity being such that the abovesaid grooves open into the cavity and constitute the slots 12b which divide the intermediate portion 4b of the socket 1b into strips 1 1b.

This being the case, there is effected on at least one of the strips llb, and preferably on two diametrically opposite strips, in the case of FIGS. 3 and 4, a transverse slit 20 separating each strip llb into two

tongues

21, 22. Through this transverse slit 20 there is introduced a tool 28 (FIG. 9).

This tool 28 includes, on one hand, a head 29 in the shape of an anvil provided with two flat surfaces 29a, 29b inclined in sauna n-rnr opposite directions, so as to form an obtuse angle, whose apex projects outwardly and, on the other hand, a handle 30. The

width 1 of the head-29 is lem than the width of the slot 20, while the length h of the head 29 is less than the large dimension of the slot 20.

To introduce the tool 28 through the slot 20, it suflices to orient the large dimension of the head or anvil 29, i.e., its length h, along the direction of the large dimension of the slot 20 and to displace the said tool 28 along a transverse direction C towards the inside of the socket lb, by making the head 29 pan; between the

free edges

23, 24 of the

tongues

21, 22.

When the anvil 29 is in the cavity 2b, the said anvil is made, by acting on the handle 30, to undergo a rotation of about 90 and the said anvilis brought into contact with the

tongues

21, 22, which are again in extension of one another, the large dimension h of said anvil 29 being then oriented in the direction of the axis of the socket lb. There is then exerted on the

tongues

21, 22, by means of the anvil 29, a force sufiicient to cause a permanent outward deformation of the said

tongues

21, 22. The tool is disengaged by repeating in reverse direction the operations which had been necessary for the introduction of the latter into the cavity 2b. This operation of deformation of the tongues is effected for all the strips 11b which have been transversely cut. In the case of FIG. 9, the anvil 29 is introduced into the cavity 2b through the slot 20 from the right to deform the

tongues

21, 22 on the left and through the slot 20 on the left to deform the

tongues

21, 22 on the right.

In a variation of the embodiment, to simplify operations, especially in the case of automatic machines, and to efiect the deformations of diametrically opposite tongues with a single introduction of the tool into the cavity 2b, there is given, as shown in FIG. 10, to the section of the anvil 29c through a plane right angles to the direction of the small dimension of this anvil, the shape of a losange. In this way, the deformation of the

tongues

21, 22 located on the left of FIG. will be obtained by a tlu'ust towards the left of the anvil 290 against the tongues, while the deformation of the

tongues

21, 22 located on the right of FIG. 10, will be obtained by a traction exerted on the tool 280 whose anvil 29c draws the tongues towards the right.

In the preceding explanations regarding the operations of deforming the

tongues

21, 22, it has been implicitly assumed that the socket lb was held by a device not shown.

Finally, the strips llb not cut transversely, are made to undergo a permanent mechanical deformation, so that the above-said intermediate portion 4b of the socket lb, becomes concave in axial direction.

The deformation of the strips 11b not being effected until after the deformation of the

tongues

21, 22, this explains why in FIGS 9 and 10, where the wcket 1b is shown at the moment of deformation of the said tongues, the slots 12b have a rectangular shape, the strips 11b not yet being deformed.

As a result of which and whatever the embodiment adopted, there is obtained a socket adapted to ensure good electrical contact, even after numerous insertions and extractions.

In fact, as explained in detail previously, due to the fact that the slots 12, [2a, 12b are closed at their ends, the strips 11 are supported by belts which are opposed to the separation of the said strips 11, 11a, 11b towards the outside of the socket. Due to the fact that the

slots

12, 12a, 12b pass through the apices of the

polygonal lines

14, 14a, 14b, the said strips have a transverse section such that they can be rendered concave in axial direction.

In addition, the embodiment of FIG. 7 enables a socket to be obtained whose mounting and locking in an insulating support are simple and rapid.

As goes without saying and as emerges already besides from the preceding description, the invention is in no way limited to those of its methods of application, nor to those of its methods of production of its various parts, which have been more particularly indicated; it embraces on the contrary all variations,

especially that in which the pol gonal contour 9, 9a, 9b would be different from those descn previously and constituted for example by a square or a rectangle.

What we claim is:

1. Socket for a prong and socket electrical contact, comprising a portion cut out into contact strips by longitudinal slots and having, over at least a fraction of its length comprising said portion, a transverse section limited internally by a closed continuous curve and, externally, by a polygonal closed line inscribed in a curve parallel to the first, wherein the longitudinal slots are closed at their longitudinal ends and pass through the vertices of the polygonal closed line and the strips of said portion are concave in an axial direction and are adapted to be deformed on the connection of the socket and a prong.

2. Socket according to claim 1, arranged for mounting in a housing provided in an insulating support, wherein at least one of said strips is cut by a transverse slot extending between two neighboring longitudinal slots into two tongues arranged head to tail with respect to one another and the tongues formed by the one or more transversely cut out strips separate outwardly so as to project by their free ends on the outer surface of the socket and to be cooperable with a locking boss provided in said housing.

3. Socket according to claim 1, wherein the closed continuous curve is constituted by a circumference.

4. Socket according to claim 3, wherein the polygonal closed line is a regular polygon with the same center as the circumference, including an even number of equal sides at least four in number.

5. Socket according to claim 4, wherein the regular polygon is a hexagon.

6. Socket according to claim 1, wherein the polygonal closed line is constituted by the contour of an equilateral triangle.

7. Socket according to claim 2, including two diametrically opposite strips, each cut into two tongues by a said transverse slot.

8. Socket according to claim 2, wherein the transverse slot is arranged substantially midway along the longitudinal slot.

9. Method of manufacturing a socket for an electrical contact according to claim 1, comprising starting with a solid prismatic body of polygonal cross section, machining grooves over a fraction of the length of the crests of the'outer surface, piercing a longitudinal cavity in the body whose cross section has dimensions such that said grooves open into the cavity and constitute slots dividing the intermediate portion of the socket into strips and then subjecting the intermediate portion of the body to permanent mechanical deformation adapted to give the strips their axial concavity.

10. Method according to claim 9 for manufacturing a socket, wherein before subjecting the intermediate portion of the body to said permanent mechanical deformation, one or several strips are provided with a transverse slot extending between two neighboring longitudinal slots, a tool in the form of an anvil is introduced, the large dimension of the anvil being oriented along the direction of the transverse slot, said anvil is subjected, inside the socket, to a rotation of about the tongues formed by the transversely cut out strip are brought into contact with said anvil, whose large dimension is then oriented at right angles to the large dimension of the transverse slot, a force sufficient to cause permanent deformation of said tongues outwardly is applied, and the tool is disengaged.

Claims

5. Socket according to claim 4, wherein the regular polygon is a hexagon.

9. Method of manufacturing a socket for an electrical contact according to claim 1, comprising starting with a solid prismatic body of polygonal cross section, machining grooves over a fraction of the length of the crests of the outer surface, piercing a longitudinal cavity in the body whose cross section has dimensions such that said grooves open into the cavity and constitute slots dividing the intermediate portion of the socket into strips and then subjecting the intermediate portion of the body to permanent mechanical deformation adapted to give the strips their axial concavity.

10. Method according to claim 9 for manufacturing a socket, wherein before subjecting the intermediate portion of the body to said permanent mechanical deformation, one or several strips are provided with a transverse slot extending between two neighboring longitudinal slots, a tool in the form of an anvil is introduced, the large dimension of the anvil being oriented along the direction of the transverse slot, said anvil is subjected, inside the socket, to a rotation of about 90*, the tongues formed by the transversely cut out strip are brought into contact with said anvil, whose large dimension is then oriented at right angles to the large dimension of the transverse slot, a force sufficient to cause permanent deformation of said tongues outwardly is applied, and the tool is disengaged.