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 Inventor Winfield Warren Loose‘ . Harrisburg, Pa. [21 1 Appl. No. 804,538 [221 Filed Mar. 5, 1969  Patented Aug. 24, 1971  Assignee AMP Incorporated ' Harrisburg, Pa.  ELECTRICAL CONNECTOR WITH SPRING HIASED SOLDER INTERFACE 5 Claims, 5 Drawing Figs.  U.S. Cl ...................................................... .. 339/223 R, 339/213 T, 339/250, 339/255 R, 339/275 T  Int. Cl ..................... ..'. ............................... ..H01r 15/12, 1-I0 l r 5/04  Field of Search ........... .§ ............................. .. 339/30, 95, 102, 210, 223, 250, 255, 258, 275, 213; 174/81; 228/56  References Cited UNITED STATES PATENTS 3,143,595 8/.1964 Martin ........................ .. 174/84 2,438,075 3/1948 Smith ...................... 339/275 B X
ABSTRACT: An electrical connector-terminal device is disclosed which features a conductor lead receiving barrel lined with solder and containing spring means adapted to be loaded by lead insertion to force the leadinto engagement with the solder prior to and during solder reflow as effected by heat applied to the device. The barrel includes a stop and projections which operate in conjunction with the spring means to mechanically stabilize the lead during solder reflow. A heat shrinkable sleeve is applied over the region of joint between the lead and the device to prevent solder escape and to seal the joint relative to the insulating sheath of the lead terminated thereby.
ELECTRICAL CONNECTOR WITH SPRING BIASED SOLDER INTERFACE
BACKGROUND OF THE INVENTION
Electrical connectors are known which feature a connector body carrying a heat shrinkable plastic insulating sleeve which serves to contain the movement of a strip of preplaced, solder when heat is applied to effect a joint between a lead and the connector body. The plastic sleeve is utilized to press or force the lead wire into the molten solder while controlling and limiting the flow of solder to a region around the lead‘. Since sufficient heat must be used to reflow the solder, the plastic insulating material utilized must have characteristics in the appropriate temperature range to not only shrink down but to also properly force the lead wire and confine the solder while the sleeve shrinks. This places a design limitation upon the choice and type of plastic insulating material employed. As an additional point, whensoldering two elements together it is preferable to have the two elements pressed firmly into engagement prior to the time the solder actually melts in order to better transfer heat to the surfaces of the elements to be soldered. lt is also preferable to maintain the elements against moving as reflow occurs and while the solder cools to a hardened state; The amount of force which can be generated by shrink-type tubingin the process of shrinking, is generally quite limited. i ‘
SUMMARY OF THE INVENTION _
The present invention relates to a solder-type electrical connector-terminal device utilized to interconnect “electrical leads. _
It is an object of the invention to provide a connector-terminal device of a construction which facilitates making solder joints at high production rates. It is another object to provide a solder-type connector-terminal which minimizes soldering skills. It is a further object to provide a solder-type connectorterminal device of a construction which stabilizes the surfaces being soldered automatically and facilitates the transfer of heat to effect solder reflow better than devices heretofore available. ,
The present invention achieves the foregoing objectives through a connector-tenninal construction blanked out of flat sheet metal stock containing a strip of solder suitably affixed to a portion of the surface area thereof, with the sheet metal blank being subsequently formed into a barrel containing one or more spring elements. The barrel is dimensioned to receive a conductive lead wire inserted therewithin with the spring element or elements being loaded by such insertion. Tangs struck into the barrel cooperate with a wire stop to hold and stabilize the wire while heat is applied to reflow the solder and join the wire to the barrel.‘ The spring element serves to force the surface of the wire and the surface of the barrel into a firm engagement to better conduct heat to the surfaces to be soldered. When sufficient heat has been generated to effect solder reflow, the spring acts to force the solder against the lead wire and into and between the strands thereof. A heat shrinkable sleeve applied in an expanded form over the barrel of the device is caused to shrink down to effect a seal around the insulation of the lead wire and prevent solder from escaping and creating a shorting path. The shrinkable sleeve plays no part in either pressing the wire into engagement with the barrel or effecting flow of the solder. It does insulate the joint at the rear of the termination.
In the drawings:
FIG. I represents a perspective view of a connector-terminal device terminated to a lead wire;
FIG. 2 represents a progression from blank to the assembled device shown in FIG. 1;
FIG. 3 depicts in cross section the barrel portion of the device, enlarged from the view shown in FIG. 1, with the stripped end of a lead wire positioned for insertion into such barrel portion;
FIG. 4 depicts the device and lead wire shown in FIG. 3, but fully inserted and terminated-thereto; and
FIG. 5 is a cross section taken along lines 5-5 of FIG. 4.
Turning now to FIG. 1, a connector device 10 is shown terminated to a cable 30.‘ FIG. 2 shows the device as blanked (to thelower left) from flat sheet metal stock, as formed (to the center), with an insulating sleeve applied and then as severed from a carrier (to the upper right). The carrier 12 includes indexing holes .13 which are utilized to index a series of devices during the manufacturethereof and thereafter-in automatic terminating equipment, providing wire insertion and movement of a series of devices to a heat applying station. Either before or after termination to a wire, depending upon thetype of automatic equipment employed, carrier I2 is severed at the juncture thereof as indicated in FIG. 2. Device 10 includes a forward contact portion 14 containing a latching element I6, adapted to cooperate with an offset in an insulating block to hold the device in operative position. Device 10 represents a male pin part of a connector and there would be a female portion similar to 10, but adapted to receive the end portion of l0 inserted therein. Viewing FIGS. 1 and 2, just to the left of junction of carrier 12 are a pair of folded-down portions, which serve as a wire stop 18 to accurately position the lead wire inserted within a barrel 20 formedat the rear of the device. Such barrel is flared at the outboard end as at 22, to facilitate a lead wire insertion. A series of tangs 23 are provided in 22 to bite into the lead wire insulation and hold an inserted lead wire in against stop 18. Overlying the barrel 20 is a sleeve of insulating material 24 which is preferably of a heat shrinkable material having an expanded configuration as shown in FIGS. 1 and 3 and a configuration following the application of adequate heat, as shown in FIG. 4. Within the base of the wire barrel 20 is a spring 38 which is positioned to extend into the interior of the barrel 20 to be loaded by wire insertion to press the lead wire against interior barrel surfaces.
FIG. 2 depicts a blank formed from flat sheet metal stock having a strip of solder material 36 applied to the upper surface thereof prior to blanking and forming of the stock. The solder strip may be laminated to the stock by heated rollers. The configurations shown in FIG. 2 may be achieved by passing the laminated stock through appropriate progressive dies to blank material and define the various portions of each element as identified by numerals common with the other views in the drawings. Following the blanking operation the stock may be rolled and formed and the insulating sleeve added as shown in FIG. 2.
Referring now to FIG. 3,‘ the barrel or rear portion 20 is shown just preparatory to the insertion of alead 30 comprised of an insulating sheath 32 and conductive strands 34. The lead is stripped so as to expose a sufficient portion of strands 34 to fit within the wire barrel when the ends of the strands abut wire stop 18. As can be seen from FIGS. 2 and 3, the solder lamination 36 is extended around the interior portion of the wire barrel 20, including the surface of spring 38. The free end of spring 38 is tumed downwardly as at 40 to avoid catching on the end of the strands 34, as the lead is inserted.
The spring 38 is joined to the base of the stock from which connector device 10 is formed at a point 39 near or under the inner surface of wire stop 18 and is deformed upwardly to present a relatively flat surface extending well into the interior of the barrel for engagement with the lead wire. The configuration given -to spring 38 makes the spring relatively stiff and its position as shown in FIG. 3 constricts the wire barrel relative to the diameter of the lead wire so that as the lead wirc is inserted to be stopped by the wire stop I8 the spring is loaded to tightly and firmly grip the lead wire within the barrel 20. The tangs 23 are oriented to hold ' the lead wire axially in against wire stop 18. Since the spring itself contains a solder surface there are at least two regions shown as I in FIG. 4 wherein an interface between the lead wire and the tenninal is maintained in a tight, firm grip. As will be appreciated by those familiar with soldering skills, the maintenance of the two surfaces to be soldered under force is highly desirable prior to