Printed circuit board contact

An electrical pin receiving socket (2,102) is disclosed which includes a base portion (6,106) having side arms (8,108) extending upwardly to a top wall (10) or contact arms (112). Back-up springs are positioned proximate the contact arms and cooperate with the contact arms to ensure that the contact arms will electrically engage a mating pin. The base section (6,106) also includes printed circuit board contacts (20,30,120,130), where the contacts (20,30,120,130) are reversely bent under the base section (6,106) and then vertically downwardly to form printed circuit board contacts (26,36,126,136), thereby allowing the electrical pin receiving socket to move relative to the printed circuit board.

FIELD OF THE INVENTION 
The subject invention relates to an improved contact for insertion into 
through holes of a printed circuit board and for receiving therethrough a 
pin terminal. 
BACKGROUND OF THE INVENTION 
The assignee of the above mentioned invention presently has a printed 
circuit board contact commercially available where the contact includes a 
base portion having printed circuit board legs extending directly 
downwardly from the base portion to be inserted into through hole sections 
of a printed circuit board The pin socket for the contact is formed by 
contact members extending from opposite side edges of the base portion at 
laterally offset sections, with the ends of the arms thence formed at 
90.degree. relative to the vertical access. The arms which extend at 
90.degree. are opposed from one another and flank a through hole which 
extends through the base section of the terminal. 
While the above mentioned contact has proven to be useful for the 
designated application, the contact does have a few drawbacks. First, 
since the contact portion is formed by the section of the terminal which 
is folded around the corner from the web which interconnects the contact 
arm to the terminal, the contact arms have a very low mating force. 
Secondly, since the terminal base portion lies adjacent to the upper 
surface of the printed circuit board, the contact has no resiliency or 
floatation in the vertical direction. Thirdly, there are only two opposed 
contacts which allows the pin to laterally slide on the contact surfaces. 
SUMMARY OF THE INVENTION 
The object of the invention then is to design a printed circuit board 
socket terminal having an increased contact force with a mating pin 
terminal 
Another object of the above mentioned invention is to design a pin 
receptacle having an ability for the receptacle to float in the vertical 
direction. 
It is a further object of the invention to provide for a pin centering 
feature within the socket. 
The above mentioned objects were accomplished by designing an electrical 
socket terminal for mounting to a printed circuit board, the socket having 
a metal base portion having printed circuit board contacts, and contact 
members extending from the base portion for receiving a pin contact 
terminal between contact sections of the contact members. Contact members 
extend from opposite side edges of the base portion of the socket terminal 
and include resilient spring portions which can extend upwardly to form 
side walls, and that the ends of the contact members are thereafter 
reversely bent downwardly towards the base portion and in opposing 
relation. 
At least one of the contact members include at its end, a bifurcated 
contact member which forms two contact arms extending from at least one 
contact member. In the preferred embodiment, each of the contact members 
include bifurcated contact arms which project downwardly towards the base 
portion. Preferably, the contact arms each have a contact surface which 
faces the center of the base portion of the socket. The contact members 
include top walls, the side walls of the contact arms extending upwardly 
to the top walls, and the contact arms extend downwardly from the top 
wall. 
In the preferred embodiment, the root of the bifurcated section is located 
in the top wall, and arcuate in shape, with the contact arms extending 
from the top walls and are angled towards the axial centerline of the 
socket. Preferably, the root portion is greater than 90.degree. and the 
contact arms extend from the root portion at a tangent to the root 
portion. The contact arms include a bend adjacent their free ends thereby 
forming a linear contact surface which is transverse to the axial 
centerline of the socket. 
In the preferred embodiment, the socket further includes a back-up spring 
which includes a base portion adjacent to the base portion of the socket 
terminal and resilient arms upstanding therefrom, the resilient arms being 
positioned adjacent to the contact arms to increase the resiliency of the 
contact arms. The back up spring resilient arms arm reversely bent, and 
the free ends of the resilient arms engage the rear surfaces of the 
contact arms. The contact arms are bent adjacent to their free ends to 
form inner corners, and the free ends of the contact arms engage the inner 
corners of the contact arms. 
In the preferred embodiment of the invention, the printed circuit board 
contacts extend from the side edges of the base portion and are reversely 
bent to extend spring sections under the base portion, which are 
thereafter bent downwardly. The spring portions are generally parallel to 
the base portion of the socket terminal. 
In the preferred embodiment of the invention, the base portion includes 
standoff sections extending therefrom which are bent downwardly. The ends 
of the standoffs are slightly above the lower surface of the spring 
portions.

DETAILED DESCRIPTION OF THE INVENTION 
With reference first to FIG. 1, the printed circuit board socket contact 2 
generally comprises an outer contact member 4 which comprises a base 
section 6 having upwardly extending sidewalls 8 which extend from end 
edges 44 and 46 (FIG. 2) of the base section 6. The sidewalls 8 extend 
upwardly to a position where the sidewalls are flattened to form top walls 
10. Bifurcated contact arms 12 are then bent downwardly to project towards 
the base surface 6, and thereafter bent proximate its free end to form an 
inside corner 18 and an exterior linear contact surface 16, the contact 
surfaces 16 being transverse to the axial direction (pin insertion axis) 
of the socket. As shown in FIGS. 1 and 2, the contact arms 12 are formed 
such that the contact surfaces 16 are perpendicular to lines which run 
through the center of the aperture 56. This is possible since the root of 
the bifurcated contact arms 12 is an arcuate section 14, of greater than 
90.degree., located in the top wall 10 of the socket contact. Since the 
contact surfaces 16 face the center of the aperture 56, the contact 
surfaces 16 tend to center a matable pin upon insertion into the socket 2. 
To increase the contact force of the contact arms 12, the socket contact 2 
includes a back up spring member 60 which has its own base section 62 
lying adjacent to the base section 6 of the socket contact 2. Arms 64 of 
the back up spring extend upwardly from the base section 62 and they are 
thereafter folded over to form back-up arms 66 which extends towards the 
contact arms 12 of the socket contact and engage the contact arms 12 at 
the corner 18 of the arms 12 as shown best in FIGS. 1 and 3. 
To increase the floatational abilities of the socket 2, the printed circuit 
board contacts 20 and 30 are themselves formed as spring members. As shown 
best in FIGS. 1 and 3, the printed circuit board contact 20 extends from 
the side edge 40 and is formed through a radiused section 22 to project a 
horizontal spring section 24 in a reverse direction generally parallel to 
the base section 6 of the socket contact member. The contact 20 is thence 
formed downwardly to form a downwardly extending contact leg 26 as shown 
in phantom in FIG. 3. Printed circuit board contact member 30 extends from 
the sidewall 42 through a radiused section 32 to project a horizontal 
spring section 34 generally parallel to the base section 6 of the socket 
contact 2. The printed circuit board contact 30 is then bent downwardly 
towards it free end to form a printed circuit board contact member 36, as 
shown in phantom in FIG. 3. 
The socket 2 also includes stand off members 50 which extend from the end 
edge surface 44 and stand off members 52 which extend from the end edge 
surface 46. As shown best in FIG. 3, the end of the stand off 50 includes 
an edge 51 which is slightly higher than the lower surface 35 of the 
horizontal arm 34. Similarly, the end edge of the stand off member 52 has 
an edge surface 53 which is slightly higher than the under surface 25 of 
the horizontal portion 24. 
To install the contact in the printed circuit through hole, the arm 36 is 
inserted into the through hole portion 302 whereas the arm portion 26 is 
inserted through the through hole portion 304 of the printed circuit board 
300 and the arms 26 and 36 are folded back on themselves to retain the 
socket to the printed circuit board, as shown in FIG. 5. 
Thus, the above mentioned socket contact has achieved the desired 
objectives. The socket contact 2 has exceptional mating force due to the 
back-up spring member 60. The contact also has a centering feature 
provided by the angle contact arms 12 facing the axial centerline of the 
socket. The socket also has better floatation than the design presently 
available. Due to the spring arms 24, 34, the socket is moveable 
downwardly towards the printed circuit board 300, to the extent of the 
distance between surfaces 50, 51; 52, 53; as shown in FIG. 3. The stop 
surfaces provided for a positive stop in the vertical direction to prevent 
overstressing the socket contact. The socket contact base section 6 can 
also move upwardly, for example due to heat expansion, due to the springs 
arms 24, 34. 
With reference now to FIG. 8, the printed circuit board socket contact 102 
generally a base section 106 having upwardly extending sidewalls 108 which 
extend from end edges 144 and 146 (FIG. 6) of the base section 106. The 
sidewalls 108 extend upwardly to a position where the sidewalls are 
bifurcated to form contact arms 112. The bifurcated arms 112 are also 
inwardly directed towards the axial centerline of the socket to form 
contact surfaces 116, the contact surfaces 116 being transverse to the 
axial direction (pin insertion axis) of the socket. As shown in FIG. 6, 
the contact arms 112 are formed such that the contact surfaces 116 are 
perpendicular to liens which run through the center of the aperture 156. 
Since the contact surfaces 116 face the center of the aperture 156, the 
contact surfaces 116 tend to center a matable pin upon insertion into the 
socket 102. 
To increase the floatational abilities of the socket 102, the printed 
circuit board contacts 120 and 130 are themselves formed as spring 
members. As shown best in FIGS. 6 and 8, the printed circuit board contact 
120 extends from the side edge 140 and is formed through a radiused 
section 122 to project a horizontal spring arm 124 in a reverse direction 
generally parallel to the base section 106 of the socket contact member 
102. The contact 120 is thence formed downwardly to form a downwardly 
extending contact leg 126 as shown in phantom in FIG. 8. Printed Circuit 
board contact member 103 extends from the sidewall 142 through a radiused 
section 132 to project a horizontal spring section 134 generally parallel 
to the base section 106 of the socket contact 102. The printed circuit 
board contact 130 is then bent downwardly adjacent to its free end to form 
a printed circuit board contact member 136, as shown in phantom in FIG. 8. 
The socket 102 also includes stand off members 150 which extend from the en 
edge surface 144 and stand off members 152 which extend from the end edge 
surface 146. As shown best in FIG. 7, the end of the stand off 150 
includes an edge 151 which is slightly higher than the lower surface 135 
of the horizontal arm 134. Similarly, the end edge of the stand off member 
152 has an edge surface 153 which is slightly higher than the under 
surface 125 of the horizontal portion 124. 
The socket contact 102 also includes strain relief ears 127 and 137 
integral with the respective contact arms 120 and 130. The strain relief 
ears 127 and 137 abut the edge of the respective stop members 150 and 152 
as best shown in FIG. 6. These ears prevent the arms 120 and 130 from 
shifting laterally inward during the formation of the vertical bend which 
forms the printed circuit board contacts 126, 136 as shown in phantom in 
FIG. 8. 
To install the contact in the printed circuit through hole, the arm 136 is 
inserted into the through hole portion 202 whereas the arm portion 126 is 
inserted through the through hole portion 204 of the printed circuit board 
200 and the arms 126 and 136 are folded back on themselves to retain the 
socket to the printed circuit board, as shown in FIG. 9. 
Thus, the above mentioned socket contact has achieved the desired 
objectives. The socket contact 102 has exceptional mating force due to the 
two bifurcated contacts 116. The contact also has a centering feature 
provided by the angled contact arms 112 facing the axial centerline of the 
socket. The socket also has better floatation than the design presently 
available. Due to the spring arms 124, 134, the socket is moveable 
downwardly towards the printed circuit board 200, to the extent of the 
distance between surfaces 150, 151; 152, 143; as shown in FIG. 7. The stop 
surfaces provided for a positive stop in the vertical direction to prevent 
overstressing the socket contact. The socket contact base section 106 can 
also move upwardly, for example due to heat expansion, due to the spring 
arms 124, 134.