Plug contact arrangement

A contact arrangement for establishing electrical contact between the plug prongs (4) of an electrical component (1) and contact bores in another electrical component (5). To permit the force-free insertion of the plug prongs (4) into the associated contact bores (6) the free width of the contact bore (6) is greater than the external dimensions of the associated plug prongs (4). To establish contact, the two components (1) and (5) are displaced relative to one another essentially perpendicularly to the direction of the plug prongs (4) and are held in the displaced position. The plug prongs (4) are deflected laterally and clamped between the upper and lower inner edges of the contact bores (6).

The invention concerns a plug contact arrangement for electrically 
connecting the plug prongs of a first electrical component with contact 
bores formed in a second electrical component and wherein the plug prongs 
are shifted perpendicularly to their longitudinal directions and thereby 
titled in the associated contact bores to make secure electrical contacts. 
In modern electronic devices the problem often exists of making electrical 
contact between components having plug prongs and other components having 
contact bores for receiving the plug prongs. To assure a good contact the 
contact prongs are generally soldered into the contact bores. This process 
is very tedious and expensive. Moreover it has the disadvantage that the 
connected components cannot be separated and exchanged without destroying 
the solder connections. To facilitate an exchange of connected components 
it is already customary to stick sockets onto the contact bore containing 
component whose feet are soldered to the contact bores. The sockets have 
plug bushings into which the contact prongs of the plug component are 
inserted. To assure a good contact in this case the plug bushings 
generally have contact surfaces which are biased with spring force against 
the plug prongs. Because of this, particularly in the case of components 
having many plug prongs, large forces have to be used in coupling and 
uncoupling the components which often leads to damage of the components. 
Another area of application in which customary contact arrangements are not 
satisfactory is the field of test adapters for testing circuit boards. The 
circuit boards to be checked generally have a very high density of circuit 
paths and circuit elements so that the number of test points is very 
large. Therefore, the test adapter must use an adapter plate with test 
pins suiting the test points of the circuit board, which test pins in turn 
are connected with the test circuit. In accordance with the customary 
WRAP-technique a cable is soldered to the lower ends of the test pins 
which cable leads to the test circuit. The preparation of such a test 
adapter is most tedious and leads, because of the uncertainties presented 
by the large number of cables to be handled by hand, to still further 
errors which are difficult to recognize and to remove. 
A further area of application in which customary contact arrangements no 
longer provide satisfactory results is that of making contact between 
several circuit boards arranged parallel to one another. This occurs 
generally with regard to so-called wiring rear walls into which these 
circuit boards are plugged and which contain the connecting circuits for 
connecting the circuit boards. 
The object of the present invention is to provide a contact arrangement of 
the type wherein the plug prongs of one component are shifted 
perpendicularly to their longitudinal directions and are thereby titled in 
the contact bores of a second component to make secure electrical contacts 
which contact arrangement is simple, assures good contact and which is 
also easily disconnectable. 
The contact arrangements of the invention are so-called zero force plug 
connectors since the contact bores have clear widths which are larger than 
the external measurements of the plug prongs or contact wires to be 
received in the bores. Therefore, the plug prongs or contact wires can be 
inserted into the contact bores without the expenditure of any force. Only 
after the insertion step are the plug prongs or the contact wires clamped 
into the contact bores by a tilting of the plug prongs or the contact 
wires, so that on one hand a secure hold and on the other hand a secure 
contact of the plug prongs or contact wires is provided with the 
associated contact bores. To release the contact arrangement the contact 
bores are again so arranged that no deflection of the plug prongs or 
contact wires transversely to their longitudinal direction is present so 
that the contact arrangement can be released with zero force.

FIG. 1 illustrates a flat cable plug 1 divided along a dividing line 2 and 
into which a flat cable 3 can be inserted in a known way. Upon assembly of 
the two parts of the flat cable plug 1 the plug prongs or bases 4 are 
brought into contact by self-cutting contact with the conductors of the 
flat cable 3. 
The circuit board 5 is provided with contact bores 6 which serve to receive 
the contact prongs 4. The inner surfaces of the contact bores 6 are 
galvanically provided with conducting material (so-called plated through 
contacts) which are connected with non-illustrated conductor paths on the 
upper surface of the circuit board 5. 
The flat cable plug 1 is provided with detent elements 8 which extend 
through and beyond detent bores 9 in the circuit board 5 and which engage 
the underside of the circuit board 5. As can be seen in FIG. 1 the detent 
elements 8 are somewhat mushroom-shaped. To assemble the flat cable plug 1 
the heads of the mushroom-shaped detent elements are so arranged relative 
to the bores 9 that they can pass through the bores. In this position the 
plug prongs 4 are likewise positioned in alignment with the contact bores 
6. The contact bores 6 have a free width which are larger than the 
external measurements of the plug prongs 4. The flat cable plug 1 can 
therefore be plugged with zero force into the circuit board 5. After this 
plugging in the flat cable plug 1 is shifted in the direction of the arrow 
10 essentially transversely to the longitudinal direction of the plug 
prongs 4 with the result that the heads of the mushroom-shaped detent 
elements 8 engage the circuit board behind the detent bores 9 (see FIG. 
1). In this position the plug prongs 4 are laterally deflected and are so 
tilted in the contact bores 6 that they come into contact with both the 
upper and lower inner edges of the contact bores 6. 
To hold the flat cable plug 1 in the assembled position illustrated in FIG. 
1, at least one of the feet 11 of the flat cable plug is provided on its 
lower side with a projection 12 which upon the shifting of the flat cable 
plug in the direction of the arrow 10 engages behind a projection 13 
formed on the upper surface of the conductor plate 5, as can be seen from 
detail A of FIG. 1 illustrated in enlarged scale in FIG. 2. 
FIG. 3 shows again a flat cable plug 15 with plug prongs 16 which insert 
into contact bores 17 in a circuit board 18. The flat cable plug 15 is 
connected in a way not illustrated in further detail with a component 19, 
for example a device wall. For the purpose of plugging the flat cable plug 
15 into the contact bore 17 of the circuit board 18 the flat cable plug 15 
is so positioned that the plug prongs 16 exactly align with the contact 
bores 17. After this plugging in the component 19 and the circuit board 18 
are shifted perpendicular to the longitudinal direction of the contact 
plug 16 relative to one another with the result that the contact prongs 16 
are laterally deflected and are thereby tilted in the contact bores 17 so 
that they are clamped between the upper and lower inner edges of the 
associated contact bores 17 to provide on one hand a good contact with the 
contact bores 17 and with the metallic inner surfaces covering these 
bores, and on the other hand a rigid mechanical hold in these plated 
through contacts is assured. 
FIG. 4 shows an arrangement with two circuit boards 22,23 parallel to one 
another. On the circuit board 22 is an electrical component 25 provided 
with plug prongs 24, for example a memory module, assembled in a way 
similar to that described in connection with FIG. 1. The component 25 is 
first positioned relative to the circuit board 22 so that the plug prongs 
24 align with the contact bores 26. After a force-free insertion the 
component 25 is shifted in the direction of the arrow 27 so that in the 
already described way the plug prongs 24 contact the contact bores 26. In 
a similar way an electrical component 28, for example a calculator module, 
is assembled on the circuit board 23 so that the plug prongs 29 of the 
component 28 contact the contact bores 30 of the circuit board 23. 
To connect the circuit boards 22 and 23 with one another a further 
component 31 is arranged between the two circuit boards 22,23, which 
component 31 is in the form of a plate parallel to the circuit boards 
22,23. This component carries contact prongs 32 which on one hand are 
received in contact bores 26a of the circuit board 22 and on the other 
hand are received in contact bores 30a of the circuit board 23. The 
component 31 is first so positioned that its plug prongs exactly align 
with the associated contact bores 26a and 30a. After the insertion of the 
plug prongs 32 in the associated contact bores the component 31 is shifted 
in the direction of the arrow 33 so that the plug prongs 32 are brought in 
the previously described way into secure contact with the associated 
contact bores 26a,30a. 
FIG. 5 shows an arrangement similar to that of FIG. 4 with two circuit 
boards 34,35 each carrying an electric component 36 or 37 which is 
connected to the circuit board in the way described in connection with 
FIG. 4. To connect the two circuit boards 34,35 with one another a 
plate-shaped component 38 is again provided between the two circuit 
boards. This component 38 is provided with bores 41 arranged in the same 
pattern as the contact bores 39 of the circuit board 34 and the contact 
bores 40 of the circuit board 35. To connect the circuit boards 34,35 with 
one another the circuit boards and the component 38 are so positioned 
relative to one another that the contact bores 39,40 and the bores 41 
align with one another. Then contact wires 42 are inserted through these 
aligned bores and the component 38 is shifted for example in the direction 
of the arrow 43 whereupon the contact wires 42 are deflected laterally and 
each is so tilted in its associated contact bores 39 and 40 that an 
electrical contact and a mechanical fixing are obtained in the already 
described way. 
FIG. 6 shows a contact arrangement for connecting circuit boards standing 
perpendicularly to one another. The circuit board 45 serves for example as 
a so-called wiring rear wall, to which the circuit boards 46,47 stand 
perpendicularly. Connected with the circuit board 46 is a component 49 
having plug prongs 48 connected to the circuit board 46 in the way already 
described in connection with FIG. 1 so that the plug prongs 48 are in 
contact with the contact bores 50 of the circuit board 46. The plug prongs 
48 stand in connection with plug prongs 51 positioned generally 
perpendicularly to them and which plug prongs are received in contact 
bores 52 of the circuit board 45. The connection of the plug prongs 48 
with the contact bores 50 of the circuit board 46 results from the 
shifting of the component 49 in the direction of the arrow 53, in the 
manner already described in connection with FIG. 1, as here not described 
again. The connection of the plug prongs 51 with the contact bores 52 
results from the shifting of the circuit board 45 in the direction of the 
arrow 54. In a similar way the circuit board 47 is connected with the 
circuit board 45 through the component 55 having plug prongs 56 and 57. 
FIG. 7 shows detail B of FIG. 6 in enlarged scale. It can be seen that the 
contact prong 56 as a result of its deflection perpendicularly to its 
longitudinal direction is so tilted in the contact bore 58 that it comes 
into intensive engagement with the upper inner edge 59 and a lower inner 
edge 60 of the metallically clad through plating 61 of the contact bore 58 
so that on one hand an electrical contact is made and on the other hand a 
mechanical holding of the plug prong in the contact bore 58 is assured. As 
especially shown by FIG. 6 the through platings are respectively connected 
with conductor paths formed on the circuit board, as is known and is not 
in itself explained in detail. 
FIG. 8 shows a contact arrangement which especially serves to connect the 
test pins 63 of a test adapter 64 with a non-illustrated test circuit. 
Test adapters for testing circuit boards generally have the following 
construction: in a fastening plate 65 are rigidly arranged test pins 63 in 
a predetermined pattern, with the test pins 63 having upwardly directed 
springy test noses 66. Above the fastening plate 65 is a support plate 67 
onto which the circuit board to be tested is laid with the test points to 
be contacted facing downwardly. The support plate 67 with the circuit 
board arranged thereon can be pushed downwardly against the force of the 
springs 68 to cause the test points to engage the test noses 66. 
The lower ends of the test pins 63 carry plug prongs or contact wires 69 
which in the present exemplary embodiment pass through aligned contact 
bores 70,71,72 of circuit boards 73,74,75 arranged parallel to one 
another. The middle circuit board 74 is supported in the test adapter 64 
for movement in the direction of the double arrow 76. For connecting the 
circuit boards 73,74,75 with one another the contact wires 69 are inserted 
through the associated contact bores 70,71,72 of the circuit boards 
73,74,75. Since the free widths of the contact bores are larger than the 
external measurements of the contact wires 69 this insertion takes place 
with zero force. After the insertion of the contact wires 69 the circuit 
board 74 is shifted toward the left as shown in FIG. 9 with respect to the 
circuit boards 73 and 75, whereby the contact wires 69 are laterally 
deflected. Thereby they are so tilted in the associated contact bores 
70,71,72 that a good electrical contact with the contact bores results in 
the already described way. 
By an increase in the number of circuit boards the number of connections of 
the individual test pins 63 can be increased as far as desired. 
The shifting of the middle circuit board 74 results for example through an 
eccentric cam 78 rotatable about an axis 77 extending perpendicular to the 
plane of the circuit board, which cam is received in an elongated opening 
79 in the circuit board 74 extending perpendicularly to the shift 
direction 76. The adjustment of the eccentric cam 78 is accomplished for 
example manually by means of a hand knob 80 connected with the shaft 81 
carrying the eccentric cam 78. 
The contact bores 70,71,72 are connected with conductor paths 82,83,84 on 
the associated circuit boards 73,74,75, which circuit paths lead to a plug 
connector 75 arranged on the edge of the circuit board, through which a 
connection to the test circuit is possible. 
FIG. 10 shows schematically the middle circuit board 74 of FIGS. 8 and 9. 
The eccentric cam 78 is adjustable along a circular path 86 and moves the 
circuit board 74 in the direction of the double arrow 76. By means of 
elongated holes 87 positioned parallel to the double arrow 76, and through 
which vertical connecting struts of the test adapter 64 pass (see also 
FIG. 8) the circuit board is guided for exact parallel movement. 
FIG. 11 shows an embodiment of the invention in which a circuit board 74a 
is adjustable along a circular path lying in its plane. Two circularly 
shaped eccentric cams 89,90 are each adjustable in synchronism along 
circular paths 91,92. They therefore move the circuit board 74a so that it 
is moved in accordance with the double arrow 93. The connecting struts 88a 
extend through circular guide openings 87a in the circuit board 74a and 
carry the circuit board 74a for exact guidance. 
FIG. 12 shows a contact arrangement in which three circuit boards 95,96,97 
are arranged parallel to one another and are to be connected with one 
another. They are provided with with aligned contact bores 98,99,100 
through which a contact wire 101 is insertable, which wire during the 
insertion step is exactly straight. The contact bores 98,99,100 have free 
widths which are larger than the external measurements of the contact wire 
101 so that this insertion takes place with zero force. Between the 
circuit boards 95 and 96 on one hand as well as between the circuit boards 
96 and 97 on the other hand are devices 102,103 for laterally deflecting 
the contact wire 101. The devices 102,103 have the form of flat plates 
provided with through bores 104 and 105 which are distributed in a pattern 
corresponding to the pattern of the contact bores of the circuit boards 
95,96,97. For connecting the circuit boards with one another the device 
102 is moved in the direction of the arrow 106 and the device 103 is moved 
in the direction of the arrow 107 whereby the contact wire 101 is 
laterally deflected into the position of FIG. 12 and is so tilted in the 
associated contact bores 98,99,100 that an electrical contact is created 
in the previously described way. The contact wires 101 are fastened in the 
illustrated embodiment to a holder plate 108 in which their ends are 
inserted into blind bores 108 and soldered in place. The holding plate 108 
can itself be formed as a circuit board as indicated by a circuit path 110 
formed on it. 
The connection of several circuit boards 95,96,97 arranged parallel to one 
another in accordance with the embodiment illustrated in FIG. 12 can take 
the place of the usual arrangement in which the circuit boards are plugged 
into a common wiring rear wall. In this customary arrangement relatively 
long connecting paths exist between components which are arranged on the 
different circuit boards since the conductor paths are directed to plug 
connections arranged on the edges of the circuit boards and pass through 
the common wiring rear wall. In contrast to this in the arrangement of 
FIG. 12 a much more direct and shorter connection is possible between the 
elements on the different circuit boards. 
FIG. 13 and FIG. 14 each show a cross-section through a plug prong or a 
contact wire, for example the contact wire 101 of FIG. 12. To improve the 
contact with the associated contact bore or with the bushing lining the 
bore, the contact wire in each case has a multi-cornered cross-section 
with sharp cutting edges 111 or 112 running longitudinally along outer 
lines. The contact wires are made preferably of spring steel and are gold 
plated. 
FIG. 15 shows an arrangement somewhat according to FIG. 5 in which a 
circuit board 200 to be tested is for example to be brought into contact 
with a first contact plate 102 and a second contact plate 202. The circuit 
board to be tested has plugged into it electronic components 203. The 
circuit board 200 to be tested has contact bores 204, the first contact 
plate has contact bores 205 and the second contact plate 202 has contact 
bores 206, the contact bores of which plates can be positioned so as to be 
aligned with the contact bores of the other plates. In these contact bores 
204, 205 and 206 are inserted contact wires 207. To facilitate this 
insertion of the contact wires 207, a guide plate 208 is for example 
arranged between the circuit board 200 and the first contact plate 202, 
which guide plate 208 is provided with guide bores 209 arranged in the 
pattern of the contact bores of the circuit board 200 or of the first 
circuit board 201. It can be seen that the contact bores 209 are formed 
toward their bottoms as funnel-shaped capturing bores to ease the 
insertion of the contact wires 207 during the inserting process. The guide 
plate 208 is movable backwards and forwardly in the direction of the arrow 
210 and is arrestable in at least its lower and upper positions. 
FIG. 16 shows an insertion process for the purpose of testing a circuit 
board 200. In FIG. 16a the guide plate 208 is shown in its upper position. 
The funnel-shaped guide bores 209 permit an insertion of the contact wires 
even if the wires are slightly displaced. The circuit board 200 is set on 
the guide plate 208 and is positioned exactly on it by centering elements 
arranged on one hand on the guide plate and on the other hand on the 
circuit board, so that the contact bores 204 of the circuit board 200 
align exactly with the guide bores 209 of the guide plate 208 (see FIG. 
16b). Then the guide plate 208 is lowered so that the circuit board 200 
likewise can be adjusted to a somewhat lowered test position in which the 
contact wires 207 can pass entirely through the contact bores 204. Then by 
opposite sided transverse adjustment of the contact plate 201 relative to 
the circuit board 200 in the previously described way a contact is made, 
with the guide bores 209 of the entirely lowered guide plate 208 not 
hindering the inclined positioning of the contact wires 207 especially 
relative to the circuit board 200. 
FIG. 17 shows an electronic component 301 provided with plug prongs 300 The 
component 301 is provided with a rectangular flange 302 which is 
receivable in a receiving groove 303 of a receiving housing 304 associated 
with the component 301. The receiving housing 304 has a bottom plate 305, 
which constitutes a guide plate for the prongs 300 by being provided with 
through bores 306 of upwardly widening funnel shape for the passage of the 
plug prongs 300. 
A cam 308 is formed on a side edge 307 of the rectangular flange 302 of the 
component 301, as especially shown in the plan view of FIG. 17a of the 
component 301. The cam 308 upon the insertion of the component 301 in a 
recess 309 in the side edge of the receiving housing 304 associated with 
the side edge 307 extends to a channel 310 running parallel to the side 
edge 307, in which channel a push bar 312 having a cam face 311 is 
slidably arranged (see also FIG. 18). For the assembly of the component 
301 the receiving housing 304 is first set onto a circuit board 313 and by 
means of centering pins 314 is positioned on the circuit board 313 and 
fastened. Then the component 301 is inserted from above into the receiving 
housing 304 with the plug prongs 300 being inserted through the capturing 
funnel forming through openings 306 into the contact bores 315 of the 
circuit board 313. In this insertion essentially no insertion force is 
required since the plug prongs 300 fit into the contact bores 315 with 
free play. Also each funnel-shaped opening or bore 306 has a minimum 
diameter or cross-section zone of very small vertical extent, obtained in 
the illustrated case of FIG. 17 by having the minimum diameters of all of 
the openings 306 contained in the plane of the bottom face of the bottom 
plate 305. Therefore, when a prong is inserted vertically into and through 
an opening 306 and its upper portion is then tilted away from the vertical 
the bottom portion of the prong will be free to also tilt away from the 
vertical by pivoting about the minimum diameter zone of the opening. In 
the position illustrated in FIG. 19 the cam 
by the cam 308 lies in the recess of the push bar 312 defined face 311. 
When the push bar 312 is pushed in the direction of the arrow 316 (see 
FIG. 18) the component 301 is pushed toward the left in the way 
illustrated in FIG. 20 with the result that the plug prongs 300 are bent 
away from vertical and their lower ends, which protrude downwardly from 
the bottom face of the bottom plate 305, are tilted in the contact bores 
315 of the circuit board 313 to provide contacts. The length of the plug 
prongs 300 is for example ten times as large as the depth of the contact 
bores 315 so that the force applied to the upper areas of the plug prongs 
300 as a result of lever effect is amplified to a ten times larger contact 
force in the area of the contact bores. 
FIG. 21 shows the arrangement of FIG. 19 in plan view. 
FIGS. 22 and 23 show an embodiment for connecting a first circuit board 400 
with a second circuit board 401 standing perpendicularly to it. In this 
case a contact arrangement 402 is used consisting of a component 404 
provided with plug prongs 403 and a receiving housing 405. The component 
404, which is connected in a suitable way to the circuit board 400 and to 
the circuit elements arranged on it, is inserted for connection into the 
component 405 connected with the circuit board 401, with the plug prongs 
403 being inserted through the funnel-shaped through openings 407, which 
capture the prongs, and into the contact bores 408 of the circuit board 
401. The component 404 is for example shiftable by hand relative to the 
receiving housing 405 in the direction of the arrow 409 and can be held in 
place by a catch element 410. An actuating tab 411 serves to release the 
catch element 410. 
As shown especially in FIG. 23 the plug prongs 403 are deflected and 
brought into contact with the contact bores 408 of the circuit board 401 
with a force amplification being achieved by the large length of the plug 
prongs 403 in comparison to the depth of the contact bores 408, as 
described already in connection with the previous embodiment. 
It is to be mentioned that the upper component 404 also can for example be 
formed as a housing for receiving a flat cable so that a construction 
corresponding to the construction of FIGS. 22 and 23 can also be used with 
circuit boards for connection to flat cables. 
FIGS. 24 and 25 show a round plug arrangement with a plug 500 and a 
receptacle 501. The plug housing 502 has at its lower end an axially 
circular flange 503 inside of which an insert 504 for holding the plug 
prongs 505 is placed. An adjusting ring is rotatably supported on the 
axially extending ring flange 503 the inside contour of which is supported 
on the ring flange and which adjusting ring in its upper region has an 
eccentric inner contour. Moreover an axially shiftable supplementary piece 
510 is arranged in the plug housing and is urged axially outwardly by a 
compression spring 512, is corresponding and which corresponds somewhat to 
the receiving housing of the previous embodiment and having a base 516 
provided with funnel-shaped capturing bores 514. 
The receptacle 507 carries at its forward end an insert 508 having contact 
bores 509 for receiving the plug prongs 505. Upon coupling of the plug 500 
with the receptacle 501 the piece 510 is urged into the piece 508 and is 
pressed inwardly against the force of the spring 512 so that the plug 
prongs 505 enter the contact bores 509. By rotation of the adjusting ring 
506 relative to the plug housing 502, which is held against rotation, and 
to the receptacle housing 507 the entire receptacle 501 is shifted 
laterally in the direction of the arrow 511 relative to the plug 500 so 
that the plug prongs 505 are bent and are tilted in the contact bores 509 
and therefore make contact with them. The relationship of the length of 
the plug prongs 505 to the insertion depth of the plug prongs 505 in the 
contact bores 509 determines again the amplification of the applied 
adjusting force into a contact force substantially increased with respect 
to the adjusting force.