Surface mount connector

A surface mount connector in which contacts mounted in two or more rows of contact passages have tails bent so that their end portions lie in a common plane for engaging traces on a printed circuit board. Each contact is a two piece part. The two parts are mounted in the corresponding contact passage from the opposite end faces of the insulator, so that the tails may be bent during the forming of the rear parts of the contacts rather than after mounting of the contacts in the passages. A retention arrangement is provided between the front and rear parts of the contacts which allows either a permanent connection between the parts, or a releasable connection so that the front and rear parts of the contacts may be removed from the passages and replaced if necessary.

BACKGROUND OF THE INVENTION 
The present invention relates generally to an electrical connector and, 
more particularly, to a surface mount connector. 
Typically, a surface mount connector comprises an insulator containing at 
least two rows of contact passages. The contacts mounted in the two rows 
of passages have rearwardly extending tails that are bent so that the end 
portions of the tails lie in a common plane for engaging conductive traces 
on the surface of a printed circuit board. The tails are normally attached 
to the traces by re-flow soldering techniques. Normally the contacts are 
initially mounted into the passages in the connector insulator while the 
tails are straight. Thereafter, the tails are formed into their desired 
configuration so that their end portions will lie in a common plane. Such 
forming of the tails after the contacts are mounted in the insulator is 
often quite difficult to accomplish particularly when the spacing between 
the rows of contacts, and the adjacent contacts in each row, is very 
close. U.S. Pat. Nos. 4,418,972; 4,628,410 and 4,631,637 disclose various 
types of surface mount connectors. 
It is the object of the present invention to provide a surface mount 
connector in which the tails of the contacts may be properly bent for 
engaging the surface of a printed board prior to mounting of the contacts 
in the connector insulator, thus overcoming the difficulties attendant 
with prior art connectors in forming the tails after the contacts are 
mounted in the insulator. Another object of the invention is to provide a 
surface mount connector which is relatively inexpensive and easy to 
assembly. 
SUMMARY OF THE INVENTION 
According to a principal aspect of the present invention, there is provided 
a surface mount connector in which the contacts are formed of two pieces, 
namely, a front mating section and a rear section which embodies the 
terminal or tail that engages the conductive traces on a printed board. 
Preferably the rear sections of the contacts are made from stamped and 
formed sheet metal. The tails are properly shaped during the forming 
operation. Thereafter, the rear sections of the contacts are inserted into 
the contact passages in the connector insulator from the rear face of the 
insulator. The front sections of the contacts are inserted into the 
passages from the front face of the insulator. Cooperating means is 
provided on the rear portion of the front section of each contact, and the 
front portion of the rear section of the contact to connect the two 
sections together when they are installed in the insulator. Each row of 
contacts may be initally attached to a carrier strip which facilitates 
insertion of the contacts simultaneously into a corresponding row of 
contact passages in the insulator. The front sections of the contacts are 
then pushed into the front of the contact passages to cause the front and 
rear sections to be connected together. Thus, by the present invention, 
the rear sections of the contacts with the tails thereon are fully formed 
prior to insertion of the rear sections into the connector insulator, thus 
avoiding the necessity of attempting to form the tails of the contacts 
after the contacts are mounted in the insulator, which is extremely 
difficult if not impossible to accomplish with very closely spaced 
contacts. The contacts may be manufactured relatively inexpensively, and 
they are easy to assemble. 
Other objects, aspects and advantages of the present invention will become 
apparent from the following description taken in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring is now made to FIGS. 1 to 7 of the drawings in detail, which show 
the first embodiment of the invention in which the front and rear sections 
of each contact are releasably connected in the connector insulator so 
that the contact may be removed from the insulator and replaced by a new 
contact. The connector, generally designated 10, comprises an elongated 
insulator 12 containing two parallel rows of contact passages 14. Each 
passage 14 extends from the front face 16 to the rear face 18 of the 
insulator. A two-piece contact, generally designated 20, is mounted in 
each of the passages 14. 
Referring now to FIGS. 5-7, each contact is comprised of a forward mating 
section 22 and a rear termination section 24. The forward section embodies 
a forward mating portion 26, an outwardly extending annular flange 28 and 
a rear portion 30. The rear portion is formed with screw threads 32. Axial 
slots 34 are formed in opposite sides of flange 28 which may receive a 
spanner wrench or like tool, not shown, that facilitates the rotating of 
the forward mating section 22 of the contact in its corresponding passage 
14. The forward section 22 of the contact may be manufactured by 
machining, cold heading, or stamping and forming. Although the forward 
mating section 26 is shown as being a pin contact, it could also be in the 
form of a socket contact, if desired. 
The rear termination section 24 of the contact comprises a tubular forward 
portion 36 and a rearwardly extending terminal 38 in the form of a bent 
tail. The rear section 24 of the contact is a stamped and formed sheet 
metal element. Preferably the tubular forward portion 36 is formed with a 
longitudally extending slot 40 therein which extends from the forward edge 
42 to the rear edge 44 of the tubular portion. A plurality of inwardly 
extending dimples or projections 46 are formed in the tubular portion 36 
which are spaced circumferentialy and axially so as to form segments of a 
screw thread which matches the screw threads 32 on the rear portion 30 of 
the forward mating section 22 of the contact. 
Reference is now made to FIG. 8 of the drawings which shows a progressive 
die stamping 50 from which the rear termination section 24 of the contact 
is produced. The stamping includes a carrier strip 52 which is initially 
formed at its left end with a plurality (only one being shown) of 
generally square sheet metal blanks 54 each attached to the carrier strip 
52 by a narrow strip 56 which ultimately becomes the tail 38 of the rear 
section 24 of the contact. The strip 56 is connected to the carrier strip 
52 by a reduced width section 58 at which the contact part may be readily 
removed from the carrier strip after a plurality of contact parts are 
mounted in the connector insulator. FIG. 8 shows four stages of the 
forming of the rear section of the contact. Initially the carrier strip 
52, blank 54 and connecting strip 56 are formed by a stamping operation on 
a sheet or metal, such as berylium copper. In a second stage of the 
operation, a plurality of angular slits 58, four being shown in FIG. 8 by 
way of example, are formed in the blank 54. At the next stage the material 
of the blank behind each slit is deformed upwardly to form a plurality of 
dimples 60 having front edges 62. At the next stage of the operation, the 
blank 54 is formed into the tubular portion 36 of the contact with the 
sides of the blank spaced apart to form the slot 40. At this or an 
additional stage, the connecting strip 56 is formed into the desired shape 
to produce the bent tail 38. The particular shape given to the tail 38 
depends upon whether the contact is mounted in the upper or lower row of 
contact passages, as seen in FIG. 1. 
Referring back to FIGS. 1, 2 and 4, it is seen that a radially inwardly 
extending annular flange 64 is provided on the wall of each contact 
passage 14, between the front and rear faces of the insulator 12. The 
flange 28 on the forward mating section of 22 of the contact provides a 
rearwardly facing shoulder 66 which engages the front of the flange 64 
when the contact section 22 is inserted into the passage 14 from the front 
face 16 of the insulator. When the rear termination section 24 of the 
contact is mounted into the passage from the rear face 18 of the 
insulator, its forward edge 42 butts against the opposite side of the 
flange 64. The dimples 46 of the tubular forward portion 36 of the rear 
termination section 24 of the contact may be either rigid or resilient. If 
the dimples are rigid, the forward and rear sections of the contact are 
interconnected by rotating the forward section clockwise (if right hand 
threads are used) relative to the rear section, by the use of a spanner 
wrench inserted into the contact passage 14 from the front of the 
insulator, so that the rear portion 30 of the forward section 22 of the 
contact will make a threaded engagement with the matching screw thread 
segments provided by the dimples 46 on the rear section of the contact. If 
the dimples 46 are sufficiently resilient, the forward section 22 of the 
contact may be connected to the rear section by simply axially pushing the 
rear portion 30 of the forward section into the tubular forward portion 36 
of the rear section of the contact. In either case, the two sections can 
be released from each other and removed from the insulator by rotating the 
forward section in a counterclockwise direction to release its threaded 
rear portion 30 from the dimples 46. 
In order to orient the tails 38 of the contacts so that their concave 
mating surfaces 38' are properly positioned for engaging the conductive 
traces 70 (only one being seen in FIG. 1) on the printed circuit board 72 
to which the two rows of contacts of the connector 10 are to be connected, 
a keying arrangement 74 is provided between the rear section 24 of each 
contact and the contact passage. As seen in FIG. 2, such keying 
arrangement may constitute a flat surface 75 on the upper wall of each 
contact passage in the upper row of passages, and a flat surface 75' on 
the lower wall of each contact passage in the lower row. The 
longitudinally extending edges 76 of the tubular forward portion 36 of the 
rear section 24 of each contact will engage the flats 75 or 75' only when 
the rear sections of the contacts are properly oriented as illustrated in 
FIGS. 1 and 2. Each flat 75 and 75' extends rearwardly from the flange 64 
to the rear face 18 of the insulator. Alternatively, as illustrated in 
FIG. 3, the keying arrangement may constitute an inwardly extending 
longitudinal key 78 which slides into the slot 40 of the tubular forward 
portion 36 of the rear termination section 24 when the latter is inserted 
into the passage 14. 
As seen in FIG. 2, the two rows of contact passages 14 are staggered 
relative to each other, in order to achieve close longitudinal spacing of 
the tails 38 of the contacts in the two rows along the side edge 80 of the 
board 72. In order to install the contacts into the insulator 12, a 
carrier strap 52, carrying a plurality of rear termination sections 24 of 
the contact, is positioned behind the insulator with the tubular forward 
portions 36 of the rear sections aligned with one row of contact passages. 
The carrier strap is then moved toward the insulator to push the tubular 
portions 36 into the rear of the passages 14 until the forward edges 42 
thereof engage the flanges 64. When inserting the rear sections of the 
contacts into the upper row of passages 14 illustrated in FIG. 2, it is 
noted that the carrier strip is oriented so that the tails 38 are adjacent 
to the lower wall of the passages. When inserting the rear termination 
sections 24 of the contacts into the lower row of passages 14, the carrier 
strip is oriented so that the tails 38 are position adjacent to the upper 
wall of th passages. Thus, the tails of the two rows of contacts will be 
as close to each other as possible as seen in FIG. 1. It is further noted 
that the tails 38 of the lower row of contacts are bent in a direction 
generally opposite to the tails of the contacts in the upper row so that 
the concave mating surfaces 38' of the two sets of tails will lie in 
substantially a common plane for engaging the traces 70 on the board 72. 
After the tubular forward portions 36 of the rear sections 24 of the 
contacts are assembled into the rear of the passages 14 in the two rows, 
blocking elements, not shown, are brought up into firm abutment against 
the rear face 18 of the insulator 12 to prevent any rearward movement of 
the rear sections 24 of the contacts when the forward mating sections 22 
are assembled into the insulator from the front thereof. A explained 
previously herein, the forward mating sections 22 of the contacts may be 
assembled to the rear sections 24 either by pushing the forward mating 
sections axially into the tubular forward portions 36, when the dimples 46 
are resilient, or by rotating the forward sections of the contacts to 
thread the rear portions thereof into the rear sections 24 of the contacts 
if the dimples 46 therein are rigid. In either case, it is preferable that 
a spanner wrench be inserted into the front of each contact passage to 
engage the slots 34 in the flange 28 to tightly thread the rear threaded 
portion 30 of the forward mating section of the contact into the tubular 
forward portion 36 of the rear section so that the rearward facing 
shoulder 66 on the forward section of the contact will tightly engage the 
front face of the flange 64 in the contact passage, and the forward edge 
42 of the rear termination section of the contact will tightly engage the 
rear face of the flange 64. The screw threading of the two contact 
sections together ensures firm and precise axial positioning of the 
assembled contact in each passage 14, thereby eliminating any axial float 
of the contact in the passage. After the contacts are fully assembled in 
the connector insulator, the carrier strips 52 may be broken off from the 
ends of the tails 38 of the two rows of contacts and the blocking elements 
for the rear sections of the contacts may be removed from the rear face of 
the insulator 12. 
To assure a low resistance connection between the front and rear sections 
of each two-piece contact 20, the rear termination section of the contact 
and/or the rear portion 30 of the forward mating section 22 of the contact 
may be provided with a solder coating prior to mounting of the contacts in 
the passages 14. Normally the tails 38 are provided with such a coating. A 
solder connection between the forward and rear sections of the contacts, 
and between the tails and the traces on the printed board 72, may be made 
in a single vapor phase soldering operation which heats the solder at both 
locations to make the desired electrical connections. 
Reference is now made to FIGS. 9-11 of the drawings which show an 
alternative embodiment of the invention. The same reference numerals used 
in FIGS. 1-8 are used in FIGS. 9-11 to indicate like or corresponding 
parts. A best seen in FIG. 11, rather than forming dimples which 
constitute segments of a screw thread as in the first embodiment of the 
invention, generally "U" shaped slots 82 are formed in blank 54 leaving a 
pair of fingers 84. In the third stage of the progressive stamping and 
forming operation, the fingers 84, are bent upwardly so that when the 
blank 54 is formed into a generally tubular configuration in the fourth 
stage, the fingers 84 will extend inwardly toward the center of the 
tubular portion. Thus, the fingers 84 extend rearwardly and inwardly when 
the rear termination section 24 of the contact is mounted into the passage 
14, as seen in FIG. 10. The rear portion 30 of the forward mating section 
22 of the contact in the second embodiment of the invention is formed with 
a tapered region 86 which terminates in a forwardly facing annular 
shoulder 88, rather than being formed with screw threads as in the first 
embodiment of the invention. When the front and rear sections of the 
contact are interconnected in the passage 14, the free ends 90 of the 
fingers 84 engage the shoulder 88. Since the fingers are formed from sheet 
metal, they are radialy resilient. Thus, when the forward mating section 
22 of the contact is pushed into the tubular forward portion 36 of the 
rear section of the contact, the fingers 84 will deflect radially 
outwardly when engaged by the curved rear end 92 of the forward mating 
section of the contact. Once the shoulder 88 passes the fingers 84, the 
fingers will snap radially inwardly to position their free ends against 
the shoulder 88, thereby firmly locking the two sections of the contact 
together. In this embodiment of the invention, the two sections of the 
contact cannot be disconnected as in the first embodiment of the 
invention. Otherwise, the structure and assembly of the connector 
illustrated FIGS. 9-11 is the same as that illustrated in FIGS. 1-8. 
Although several embodiments of the invention have been disclosed herein 
for purposes of illustration, it will be understood that various changes 
can be made in the form, details, arrangement and proportions of the 
various parts in such embodiments without departing from the spirit and 
scope of the invention as defined by the appended claims.