U.S. patent number 3,744,005 [Application Number 05/159,179] was granted by the patent office on 1973-07-03 for zero force type connector block.
This patent grant is currently assigned to Berg Electronics, Inc.. Invention is credited to Fred C. Sitzler.
United States Patent |
3,744,005 |
Sitzler |
July 3, 1973 |
ZERO FORCE TYPE CONNECTOR BLOCK
Abstract
A zero force connector block having a number of snap-over-center
type terminals arranged along a circuit board receiving slot and a
cam bar operable to engage the terminals serially and move contact
portions on the terminals into engagement with a contact on a
circuit board inserted into the slot. As the terminals move into
engagement with the circuit board they move other terminals into
engagement with different contact portions of the circuit
board.
Inventors: |
Sitzler; Fred C.
(Mechanicsburg, PA) |
Assignee: |
Berg Electronics, Inc. (New
Cumberland, PA)
|
Family
ID: |
22571420 |
Appl.
No.: |
05/159,179 |
Filed: |
July 2, 1971 |
Current U.S.
Class: |
439/260; 439/108;
439/637 |
Current CPC
Class: |
H01R
12/89 (20130101) |
Current International
Class: |
H01R
12/16 (20060101); H01R 12/00 (20060101); H01r
013/54 () |
Field of
Search: |
;339/74,75,176 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
IBM Technical Bulletin, Agard et al., 1971-02, Vol. 13, No. 9, p.
2612,.
|
Primary Examiner: McGlynn; Joseph H.
Claims
What I claim as my invention is:
1. A zero force type connector block comprising an insulating body;
a series of terminals attached to said body; the body including
means for positioning a support carrying a number of contacts with
a contact adjacent each terminal; each terminal including a tention
leg secured to and extending from the body, a compression leg
secured at one end to the free end of the tension leg with the
other end thereof engaging a stop and a terminal contact movable
with movement of the legs toward and away from the adjacent
contact, and; and means for stressing each terminal to effect
relative movement of the axis of the tention leg past the
compression leg stop and thereby bring the terminal contact into
engagement with the adjacent contact.
2. A zero force type connector block as in claim 1 including a
second terminal associated with each of said terminals; each second
terminal being secured to the body and including a spring leg with
a contact point on the free end thereof located between the said
associated terminal a second contact on the support, the spring leg
being biased toward said terminal; and a movable insulating spacer
between the spring leg and said terminal whereby each second
terminal is moved toward and away from the adjacent second contact
by movement of the associated said terminal.
3. A zero force type connector block as in claim 2 wherein said
insulating spacers are secured to said second terminals.
4. A zero force type connector block comprising an insulating body;
a series of terminals attached to said body; the body including
means for positioning a support with a contact on the support
adjacent each terminal; each terminal including a tension leg
secured to and extending from the body adjacent a contact, a bowed
compression leg secured at one end to the free end of the tension
leg with the other end thereof engaging a stop located a distance
from the connection between the legs less than the length of the
tension leg outwardly of the body, and a terminal contact movable
with movement of the legs toward and away from the adjacent
contact; a recess in the body communicating with each of the
terminals; and means in said recess for engaging each of the
terminals and effecting relative movement of the free end of the
compression leg past the tension leg to snap the terminals and
bring the terminal contacts into engagement with the adjacent
support contacts.
5. A zero force type connector block as in claim 4 wherein said
means includes a cam operable to move the terminals serially.
6. A zero force type connector block as in claim 5 wherein the
recess includes a cam path extending along the body past each of
the terminals and wherein the cam comprises an elongate cam bar
longitudinally movable along the cam path and having a single rise
surface to move the terminals.
7. A zero force type connector block as in claim 6 wherein said
means includes a plurality of slides engagable with said terminals,
each slide extending from a terminal to the cam path and including
a follower surface engagable with said rise surface to shift the
slide and thereby move the terminal.
8. A zero force type connector block as claim 6 wherein each
terminal includes a portion extending into said cam path and
directly engagable with said cam rise surface to move the
terminal.
9. A zero force type connector block as in claim 4 including an
electrically isolated follower terminal associated with each
terminal and movable therewith to engage a contact on the
support.
10. A zero force type connector block as in claim 4 including a
second terminal associated with each of said terminals; each second
terminal including a spring portion secured to the block with a
terminal contact on the free end thereof; a movable insulating
spacer confined between each of the terminal pairs; each of the
second terminals being biased away from the support and toward the
associated second terminal whereby each second terminal is moved
toward and away from an adjacent second contact by movement of the
associated said terminal.
11. A zero force type connector block comprising an insulating
body; a series of terminal recesses formed in the body and
extending along the body adjacent a circuit board support; a
snap-over-center type terminal and a follower terminal in each
recess with a portion of the follower terminal between the
snap-over-center terminal and the mouth of the recess and a movable
insulating spacer between the terminals to electrically separate
the same; and terminal shifting means for engaging each of the
snap-over-center terminals to move the same toward a circuit board
in the circuit board support with a pair of contacts on the circuit
board opposite each recess to snap the terminals and bring contacts
on the snap-over-center terminals into engagement with contacts on
the circuit board, movement of the snap-over-center terminals by
said means operating to move the follower terminals to bring the
contacts thereon into engagement with contacts on the circuit
board.
12. A zero force type connector block as in claim 11 wherein said
terminal shifting means comprises a cam bar having a single rise
surface movable along said block for serially movement of the
snap-over-center terminals to the engaged position.
13. A zero force type connector block comprising an insulating body
having a series of terminal recesses extending along a circuit
board support; a snap-over-center terminal and a follower terminal
confined in each recess; each snap-over-terminal including a
tension leg secured to and extending from the body, a bowed
compression leg secured at one end to the free end of the tension
leg and extending back generally parallel to the tension leg with
the other end thereof engaging a stop and a terminal contact
movable with movement of the legs into and out of the recess for
forming an electrical connection with a contact outside of the
recess; each follower terminal including an elongate spring member
extending from the block with a contact at the free end thereof, a
part of the spring member being located between the tension leg of
the adjacent snap-over-center terminal and the mouth of the recess
and biased toward the tension leg; a movable insulating spacer
confined between the portion of the follower terminal and the
tension leg; an elongate cam bar movable along the block past the
recesses and including a rise surface; and an operative connection
between each of the snap-over-center terminals and the rise surface
as the same is moved past the terminal to snap the terminal and
thereby move the contacts of both snap-over-center terminals and
the associated follower terminals out of the recesses and into
engagement with associated contacts on a circuit board in the
support.
14. A zero force type connector block comprising an insulating body
having a series of terminal recesses extending along a contact
support; a snap-over-center terminal and a follower terminal
confined in each recess; each snap-over-terminal including a
tension leg secured to and extending from the body, a bowed
compression leg secured at one end to the free end of the tension
leg and extending back generally parallel to the tension leg with
the other end thereof engaging a stop and a terminal contact
movable with movement of the legs into and out of the recess for
forming an electrical connection with a contact outside of the
recess; each follower terminal including an elongate spring member
extending from the block with a contact at the free end thereof, a
part of the spring member being located between the tension leg of
the adjacent snap-over-center terminal and the mouth of the recess
and biased toward the tension leg; a movable insulating spacer
confined between the portion of the follower terminal and the
tension leg; and means for snapping the snap-over-center terminals
and thereby moving the contacts of both the snap-over-center
terminals and the associated follower terminals out of the recess
and into engagement with contacts on the contact support.
15. A zero force type connector block comprising an insulating body
having a series of terminal locations therein; means for
positioning a contact adjacent each terminal location; a two
position snap-over center type terminal secured to the block in
each terminal location, each terminal including a tension leg, a
compression leg and a contact movable with the legs;and a cam
engagable with the terminals to snap the same to move the terminal
contacts from a position remote from the adjacent contacts to a
position against the adjacent contacts.
Description
THE INVENTION
The invention relates to zero force type connector blocks where a
circuit board or like member is freely inserted into a slot formed
in an insulated housing without engagement between the board and
the terminals confined in the housing. The free insertion of the
board into the block eliminates wear at the terminal contact areas
during insertion. A row of snap-over-center type terminals is
confined in the block along the open circuit board slot defined by
ribs between adjacent terminals. The terminals are in the
disengaged position during insertion of the board so that the
contact portions are free of the board. The board may be directly
inserted into the slot or it may be moved laterally along the slot
to reach the contact position. After the board is inserted, a cam
bar is moved longitudinally along the length of the block to engage
the terminals serially and move or snap the same over-center to the
engaged position where the terminals contacts are spring biased
against the contact areas on the circuit board. The cam bar may
engage the snap-over terminals directly or may engage a slide
member to move the slide member and thereby shift the terminals.
The terminal contacts are brought into engagement with the circuit
board contact areas without protracted wiping along the surface of
the circuit board so that the terminal contact areas are not worn
away by frictional contact with the circuit board. This is
important since the terminal contacts are frequently provided with
a conductive coating or plating of a precious metal such as gold
which improves the contact properties but is easily worn away. When
the cam bar is fully inserted into the block, all of the terminals
are in contact with contact portions along the circuit board.
Because the contacts are brought into engagement with the circuit
board one at a time, or serially, with the insertion of the cam
bar, the insertion force required to move the cam bar along the cam
path is maintained at a relatively low level. This is important
because of the present requirement of a large number of terminals
per connector block row. Sometimes as many as 40 or more terminals
are required per row. This means that the force required to shift
all of the terminals simultaneously from the disengaged to the
engaged positions is quite high. In some instances the force
required to shift the terminals simultaneously would be too large
to permit manual shifting of a cam bar. In other cases, the cam bar
is not strong enough to transmit the required forces without
buckling or breaking.
In some applications it is desirable to establish a second
connection with a circuit board adjacent each snap-over-center
terminal in the block. These connections may be used for the
establishment of ground or reference voltages on the circuit board.
Spring leaf terminals are located adjacent each snap-over-center
terminal in the block and are biased toward the terminal so that an
insulating button or spacer carried by the spring leaf is held
against the terminal. Shifting of the snap-over-center terminal
into engagement with the circuit board moves the leaf terminal so a
contact point on the terminal engages the ground or reference
voltage contact on the circuit board. The leaf terminal contact is
free of the circuit board slot prior to engagement to prevent
contact wear as the circuit board is positioned within the circuit
board slot.
BACKGROUND OF THE INVENTION
Snap-over-center type contacts have been long used in small
electrical switches of the push button type as disclosed in U.S.
Pat. Nos. 1,960,020 and 2,172,673. In U.S. Pat. No. 2,901,568 an
insulating button is provided between a pair of snap-over-center
type contacts so that shifting of one contact causes the second
contact to shift. U.S. Pat. No. 3,541,490 discloses a zero force
type connector block in which spring terminals confined within the
block are serially brought into electrical connection with pins
extending into the block by inserting a cam bar along the length of
the block to engage and stress the terminals. Other zero force type
connector blocks for circuit boards have been proposed in which the
terminals are removed from the circuit board slot during insertion
and are then simultaneously brought into engagement with the
contact on the circuit board through the use of a rotary cam or
longitudinally movable cam bar. The rotary cam and cam bar
simultaneously engage the terminals to bring them into engagement
with the circuit board at the same time. See, for instance, U.S.
Pat. Nos. 3,478,301, 3,537,063 and 3,553,630.
other objects and features of the invention will become apparent as
the description proceeds, especially when taken in conjunction with
the accompanying drawings illustrating the invention, of which
there are four sheets.
IN THE DRAWINGS:
FIG. 1 is a partially broken away perspective view of a connector
block according to the invention;
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1 with the
terminals on the left of the view in the open or disengaged
position, and the terminals on the right of the view in the closed
or engaged position;
FIGS. 3, 4 and 5 are sectional views taken along lines 3--3, 4--4
and 5--5 respectively of FIG. 2;
FIG. 6 is a perspective view illustrating a pair of terminals
removed from the block;
FIG. 7 is a broken away view illustrating engagement between the
terminals and the block;
FIG. 8 is a perspective view of a cam rod used to move terminals in
adjacent blocks from the open to the closed positions;
FIG. 9 is an enlarged view of a portion of FIG. 8;
FIG. 10 is a view of a cam rod similar to that of FIG. 8 for
engaging the terminals on one side of a single block;
FIG. 11 is a sectional view taken through a connector block
illustrating a further embodiment of the invention wherein the cam
rods engage the free ends of the contacts. The block is in the open
position;
FIG. 12 is similar to FIG. 11 but with the terminals in the closed
position; and
FIG. 13 is a sectional view taken along line 13--13 of FIG. 12.
Connector block 10 includes an insulating body 12 which may be
formed from a suitable plastic having a base 14 and a pair of
upstanding sidewalls 16 and 18. Ribs 17 and 19 extend from the
sidewalls and define the sides of a circuit board receiving recess
20 running longitudinally along the body from end 21. Terminal
cavities 22 are formed between adjacent ribs 17 and 19 to each side
of recess 20 and extend from the ends of sidewalls 16 and 18 below
the bottom of the recess. A cam path or recess 24 extends
longitudinally along the outer surface of each sidewall past
recesses 22 and is connected to each of the recesses by a passage
26.
A pair of contact terminals 28 and 30, best illustrated in FIG. 6,
is confined in each recess 22 for engagement with the circuit board
when positioned in slot 20. Each of the terminals is provided with
a tail portion 32 which extends from the bottom of a recess 22
through an opening 34 provided in base 14 for engagement with
printed circuitry or suitable circuit means on circuit board 36.
U-shaped spring tabs 38 formed in the sides of tails 32 at the
connection with the terminals are seated in recesses 40 at the
upper end of holes 34 in order to secure the terminals to the body
12 in desired locations.
Each terminal 28 includes a tension leg formed from a flat thin
strip of metal which extends from tabs 38 to terminal free end 44.
As illustrated in FIG. 4, the edges of the medial portion 46 of leg
42 are bent together to reduce the width of the leg.
Compression leg 48 extends from free end 44 toward the tail 32 and
is bowed away from the tension leg toward recess 20. A contact
point 50 may be formed in leg 48 for engagement with circuitry on
board 52 when positioned in slot 20. The tension leg 48 may be
formed from an extension of the strip forming leg 28 and joined to
leg 28 by means of a reverse bend at end 44. Crimp tabs 54
extending from the end of the tension leg engage the end of the
compression leg so that the ends of both legs are held together
securely at free end 44. The crimp prevents shifting of the
compression leg along the longitudinal axis of the tension leg.
Fingers 56 are formed in the free end 58 of tension leg 48 so that,
as also illustrated in FIG. 4, the fingers may project past the
reduced width portion 48 of the compression leg as in FIG. 2.
Ground terminal 30 includes an upwardly extending leaf spring 60
with a contact point 62 formed in the free end thereof. A pair of
tabs 64 extend from the median portion of leg 60 in a direction
away from point 62 and as indicated in FIG. 4 clasp insulating
button or spacer 66.
With both snap-over-center terminals 28 and ground or follower
terminals 30 mounted in body 12, the spring bias of leg 60 holds
the spacer 66 against the tension leg 42 of terminal 28. Movement
of terminal 28 between the opened and closed positions is
transmitted to terminal 30 through the spacer 66 so that the
terminal follows terminal 28 and is moved between the opened and
the closed positions.
An insulating slide 68 is confined in each passage 26. The end of
each slide which extends into a recess 22 includes a pair of spaced
apart finger supports 70 located to either side of the reduced
width portion 46 of tension leg 28. The ends of compression leg
fingers 56 are seated in recesses 72 formed in the tops of supports
70 so that legs 48 are maintained under compression and bowed
toward the circuit board recess 20. The sides of passages 26 extend
into cam path 24 forming ridges 74 located to either side of slide
68. The width of the slides above ridges 74 is increased at 71 so
that adjacent slides nearly touch each other. This increased width
prevents the slides from moving into recesses 22 when positioned as
illustrated on the left side of block 10 in FIG. 2. An upwardly
projecting follower 76 is formed on the top of each slide 68. As
indicated in FIG. 3 the projection 76 extends along the full width
of the slide. The follower 76 is generally rectangular with bevels
78 at opposite corners thereof.
FIG. 10 illustrates a cam bar 80 useful for insertion along a
single cam recess or path 24 to engage the followers 76 extending
into the path and thereby move the slides 68 between the positions
illustrated in FIG. 2. The cam bar 80 is used on the side of the
block 10 which is not contiguous to additional blocks where
insertion of the bar moves one side of the slides only. The cam
bars and slides are all formed of insulating material to prevent
cross circuits between adjacent terminals 28.
Cam bar 82, illustrated in FIGS. 8 and 9, is inserted into the cam
recess or paths 24 of two adjacent blocks 10, as illustrated on the
right of FIG. 2, to move the two sets of adjacent slides 68. A
number of blocks 10 may be mounted in side by side relationship as
indicated in FIG. 2 for mounting a number of daughter boards 52
upon a single mother board 36.
Cam bar 80 comprises a longitudinal body portion 84 having a
bevelled lead end 86 and a handle 88 at the other end thereof.
Groove 90 extends along the length of the bar and is provided with
a rise section 92 adjacent lead end 86 so that the portion of the
groove at end 86 is laterally offset from the remainder of the
groove. As indicated in FIG. 12, the cam bar 80 is inserted into
recess 24 from one end of block 12 so that the projections 76 on
the slides at the lower end of the recess are fitted in the end of
the groove 90 at the lead end of the bar. Movement of the bar along
the groove brings the rise section 92 of the groove 90 into
successive engagement with one of the bevelled corners 78 on
projections 76 in order to shift the slides outwardly of the
recesses 20 from the position illustrated on the left in FIG. 2, to
the position illustrated on the right in FIG. 2. Thus, as the bar
is inserted the slides 68 are successively moved outwardly of the
recesses. Because each slide is moved one at a time, the amount of
force required to insert the bar is relatively low and relatively
uniform.
Cam bar 82 is inserted in the double cam path defined by the pair
of recesses or paths 24 between the abutting walls of the two
adjacent blocks 10, as indicated in FIG. 1. Insertion of the bar
sequentially moves both sets of slides 68 in the adjacent blocks 10
away from their respective recesses 22. In some cases it may be
desirable to offset the rise sections 94 of the two cam recesses 96
on the bar longitudinally so that during insertion the slides in
the two blocks are moved alternatively. In this way the cam bar
does not shift opposing slides in the two blocks at the same time
and the insertion force is reduced.
Terminal 28 is of the snap-over-center type having an engaged or
contact position and a disengaged or open position. When in the
disengaged position, illustrated by terminal 28 in the left hand
recess 22 of FIG. 2, the tension axis of leg 42 is located to the
left of the compression axis of leg 48. The two axes cross at crimp
connections 54. The axial length of the tension leg 42 from the
connection between the leg and the body 10 to the connection
between the free end of the tension leg and the compression leg at
crimp 54, is greater than the distance between such connection and
the ends of fingers 56, as measured along the compression axis of
leg 48, so that when the legs are positioned as on the left in FIG.
2, the compression leg 48 tends to lengthen and thereby rotate the
tension leg in a counter-clockwise direction to bias the free end
44 of the terminal against the bottom of recess 22. In this
position the contact 50 is withdrawn from the circuit board recess
20. The spring bias of terminal 30 maintains the insulating spacer
66 against the tension leg 42 at all times so that when the
terminal 28 is positioned as in the left of FIG. 2, contact tip 62
is also located within recess 22. With cams 80 and 82 withdrawn the
slides 68 in walls 16 and 18 are all extended into their respective
recesses 22 and all terminal contact points 50 and 62 are withdrawn
from the circuit board holes 20. The daughter board 52 may be
freely inserted into the recess without wear on any of the terminal
points 50 and 62. As mentioned, the board 52 may be inserted
directly into cavity 20 or may be moved laterally into the cavity
from block end 21.
After the circuit board 52 has been positioned within the block 10,
the cam bars are inserted within the recesses 24 and the slides 28
are serially withdrawn from the recesses 22. As the slides are
withdrawn, the compression axis of each compression leg 48 is
pivoted back toward the tension axis of each tension leg. When the
compression axis pivots past the tension axis, the compression leg
48 then rotates the tension leg away from the bottom of the recess
22 toward the circuit board 52 thereby moving the contact point 50
into engagement with circuitry 98 on the board. Movement of the
tension legs toward the circuit board pivots the spring leaves 60
of terminals 30 toward the circuit board to bring contact points 62
thereof into electrical connection with printed circuitry 100 on
the board. A resilient high pressure electrical connection is
formed between each of the contact points 50 and 62 and their
respective contacts 98 and 100. Spring pressure urging contact
points 62 against pads 100 is provided in part by the resiliency of
strip 60 and in part by the compression leg which biases the
tension leg 42 toward the circuit board.
The tabs 54 at the free end of the terminal 28 secure together the
ends of legs 42 and 48 so as to prevent any movement of the end of
leg 48 relative to the end of leg 42. The rigid connection is
required to prevent lengthening of leg 48 along the axis of leg 42.
Other means, such as a rivet or weld, may be used in place of the
tabs to secure the ends of the two legs together and prevent
relative axial movement thereof.
In the connector block 10 the terminals are serially brought into
engagement with the circuit board by the insertion of the cam bar.
When the cam bar is withdrawn from the block the terminals are held
in the disengaged position by the tension leg permitting ready
insertion and withdrawal of the circuit board.
The embodiment of FIGS. 1 thru 11 uses a snap-over-center terminal
in which the snap action is achieved by moving the free end of the
compression leg so that the compression axis is brought past the
axis of the tension leg. In this way the terminals 28 are either
biased toward the bottom wall of recess 22 or toward the circuit
board. This snap-over-center action may be achieved in other ways
whereby the compression axis is moved past the tension axis. Thus,
as in the embodiment illustrated in FIGS. 11 and 12, the free end
of the compression leg may be fixed and the cam bar may engage the
free end of the terminal in order to move the same so that the axis
of the larger compression leg is moved past the axis of the longer
tension leg. In this embodiment the force required to shift the
terminal may be applied to the terminal at points other than the
terminal free end. Thus, the shift force could be applied, by means
of a cam or a slide actuated by a cam, to a point somewhere along
the tension leg above the junction between the leg and the body or
even directly to the compression leg at a point above the junction
between the leg and the body. As will be apparent from the
description of the embodiment of FIGS. 11 and 12, the embodiment as
illustrated does not require a slide interconnecting the cam and
each terminal.
Connector block 110 of FIGS. 11 and 12 includes an insulating body
112 having a number of recesses 114 formed therein to either side
of a central longitudinally extending circuit board recess 116. A
terminal 118 includes a tension leg 120, compression leg 122, tail
124 and locating tabs 126, all of which are similar to the
corresponding elements of the previously described terminal 28 used
in block 10. As in terminal 28, the free end of the compression leg
122 is provided with spaced fingers 128. The ends of the fingers
are seated in fixed pockets formed in spaced supports 130 which
extend into the recess 114.
A crimp connection 132 secures the free end of the tension leg 120
to the end of the compression leg 122. An extension 134 of terminal
118 past the crimp 132 is laterally offset at 136. The extension
projects into cam path or recess 137 at the top of the block
sidewall.
As illustrated in FIG. 12, a cam bar 138 having a recess 140
therein may be inserted along the top of each side of body 112 in
path 137 with the recess 140 fitted around block ridge 142. Each
cam bar 138 includes a cam recess 144 having an offset rise portion
146 located adjacent the lead end of the bar.
When the cam bars 138 are withdrawn from the block 110, as
illustrated in FIG. 11, the compression axes of legs 122 are
located nearer the circuit board recess 116 than the tension axis
of legs 120 so that the compression legs bias the tension legs
against the bottom of recesses 114. The block is provided with a
pair of ground contact terminals 148 indentical to terminals 30 in
FIG. 2. With the cams withdrawn the contacts 150 of terminals 118,
and contacts 152 of terminals 148 are withdrawn from recess 116
thereby permitting ready insertion of circuit board 154 without
engagement of the contact during insertion. After the circuit board
has been seated in recess 116 the cam bars 138 are inserted along
ridges 142 with the terminal projections 136 seated in recess 144.
Movement of the cam bars serially moves the projections 136 toward
recess 116 so that tension axes of terminal legs 120 passes the
compression axes of the legs 122 and the contacts 150 are biased
toward and into engagement with contacts 156 on the board 154. The
movement of terminals 118 into engagement with circuitry 156 also
moves the contacts 152 of terminals 148 into engagement with
printed circuitry 158 on the board. This position is illustrated in
FIG. 12.
While in both embodiments the compression legs and tension legs are
formed from an integral strip of metal with the joining ends
secured together by a crimp, obviously separate compression and
tension legs could be used with their legs secured together. The
disclosed construction has the advantage of avoiding contact
resistance in the circuit path extending from the contact point to
the connection at the terminal tail.
Daughter boards are frequently inserted into connector blocks when
there is an applied voltage between the terminals in the block. By
removing the contacts of both terminals in each of the terminal
pairs, it is possible to move the daughter board to the contact
position without engagement between the terminal contacts and
contact pads on the daughter board other than those with which
connections are desired. It is not possible in conventional
connector blocks to have two electrically hot terminals at a given
location along a series of terminals because during insertion of
the circuit board past the contacts of the pair the contact of one
of the terminals engages a circuit contact on the daughter board
intended for connection with the other terminal contact. Such
connections, even if momentary, are highly undesirable since the
application of an undesired voltage to a contact pad on the
daughter board could ruin circuitry on either the mother or
daughter board. In the connector blocks as disclosed, the contacts
of each terminal pair are located at the same distance along the
series of terminal pairs at each side of the circuit board cavity.
By using this construction, together with zero force terminals, the
undesirable cross circuits are prevented.
While I have illustrated and described preferred embodiments of my
invention, it is understood that these are capable of modification,
and I therefore do not wish to be limited to the precise details
set forth, but desire to avail myself of such changes and
alterations as fall within the purview of the following claims.
* * * * *