Multi-row connector comprising flexible contact sheets with insulating resilient pieces

For electrically connecting a conductor pattern (25) printed on a surface of a flexible insulator sheet (23) to a circuit board (13), an insulating resilient piece (33) is attached to the opposite surface of the flexible sheet and obliquely projects from said opposite surface. A connecting member (15) having a contact (17) to be electrically connected to the circuit board has an insulator block (16) having a receiving hole (18) for receiving the flexible sheet and the resilient piece together. The contact is exposed in the receiving hole so that the contact is brought into contact with the conductor pattern of the flexible sheet when a projecting portion of the resilient piece is pressed towards the flexible sheet received in the receiving hole by an actuating member (31, 39, 41). By the use of the connecting arrangement, a multi-row connector (11) is assembled which is for establishing electric connection to the connecting member as a paired connector. The multi-row connector comprises a first insulator block (19) for receiving the flexible sheets as flexible contact sheets in sheet receiving holes (21) and a second insulator block (27) having a sheet receiving groove (29). The insulating resilient pieces are fixed to bottom sheet ends of the flexible contact sheets. After inserted between free ends of the resilient pieces, the actuating member is turned around its axis to establish the electric connection.

BACKGROUND OF THE INVENTION 
This invention relates to an electrical connector for electrically 
connecting a flexible printed circuit board to a connecting object, such 
as an FPC (flexible printed circuit) connector, which is of a ZIF (zero 
insertion force) type and is for connection with a minimal operating 
force. 
Japanese patent publication (B2) No. 11,105 of (1982) discloses a connector 
for electrically connecting a flexible printed circuit board to another 
printed circuit. The flexible printed circuit board comprises a flexible 
insulator sheet with front and rear surfaces and a sheet end and a 
conductor pattern extending on said front surface to said sheet end. A 
rigid insulator plate is bonded onto the rear surface of the flexible 
printed circuit for reinforcing the flexible board. A connector member is 
mounted on the circuit board. The connector member has an elastic contact 
having a terminal portion which is electrically connected to the circuit 
board. The connecting member has an connector insulator having a contact 
hole in which the elastic contact is supported to elastically project a 
contact portion thereof. In order to establish connection of the conductor 
pattern with the contact, the flexible printed circuit board is inserted 
together with the rigid insulator plate into the contact hole against a 
pressing force due to the elasticity of the elastic contact. Therefore, 
the connector is not a ZIF type. The conductor pattern is 
disadvantageously damaged by friction with the contact during connecting 
operation. Accordingly, the flexible printed circuit results in a 
decreased life time. 
There are known in the prior art various multi-row connectors using the 
flexible printed circuit boards having a plurality of conductor patterns 
as contact sheets. Examples are disclosed in U.S. Pat. No. 4,881,908, in 
U.S. Pat. No. 4,892,487, and in U.S. Pat. No. 5,102,342. 
It is possible in these prior documents to understand that the paired 
connector comprises contact rows of a plurality of contacts in each 
contact row. The multi-row connector comprises a first insulator block 
having a sheet receiving hole. A pair of flexible contact sheets has 
individual front surfaces and individual sheet ends. On each front 
surface, rows of parallel conductor patterns are arranged to reach the 
sheet ends and are not less in number than the contacts in each contact 
row of a paired or mating connector. The flexible contact sheets are 
received in the sheet receiving hole in a back to back opposing relation. 
A second insulator block has a sheet receiving groove for receiving the 
flexible contact sheets with the sheet ends protruded through the sheet 
receiving groove. An actuating member is for actuating the flexible 
contact sheets to bring the parallel conductor patterns near to the 
contacts of the paired connector after the second insulator block is 
brought into contact with the paired connector to place the parallel 
patterns near to the contacts at the sheet ends. 
It is additionally possible to understand that the multi-row connector is 
further for connection to a daughter board having a pair of board surfaces 
and a shim end having a predetermined thickness between the board 
surfaces. A plurality of conductive patterns are formed on the board 
surfaces in correspondence to the conductor patterns of the flexible 
contact sheets. 
In such a conventional multi-row connector, it takes too much labour or 
many operations to bring the connector into mechanical contact with the 
paired connector with the conductor patterns brought into electric contact 
with the contacts of the paired connector. Besides, it is hardly possible 
to use a plurality of FPCs in the conventional multi-row connector with a 
high contact density. 
SUMMARY OF THE INVENTION 
It is a principal object of this invention to provide an electrical 
connector of a ZIF type for electrically connecting a flexible printed 
circuit board to a connecting object to insuring a long life time of the 
flexible printed circuit board. 
It is another principal object of this invention to provide a multi-row 
connector which can be connected to a paired connector without many 
operations. 
It is another object of this invention to provide a small multi-row 
connector with a plurality of FPCs used and with a high contact density 
achieved. 
It is a subordinate object of this invention to provide a multi-row 
connector which is of the type described and which is for used in 
establishing electric connection between a daughter board and the paired 
connector used as a mother board. 
Other objects of this invention will become clear as the description 
proceeds. 
According to the present invention, there is provided an electrical 
connector for electrically connecting a flexible printed circuit board to 
a connecting object, the flexible printed circuit board comprising a 
flexible insulator sheet with front and rear surfaces and a sheet end and 
a conductor pattern extending on the front surface to the sheet end. The 
electrical connector comprises: an insulating resilient piece having an 
end portion and an extension portion extending from the end portion in a 
different direction from the end portion, the insulating resilient piece 
being attached to the rear surface of the flexible printed circuit board 
so that the end portion is arranged to the sheet end of the flexible 
printed circuit board and the extension portion extending away from the 
rear surface of the flexible printed circuit board; a connecting member 
for being electrically and mechanically connected to the connecting 
object, the connecting object comprising an insulator block and a contact 
supported in the insulator block, the contact having a terminal end 
connected to the connecting object and a contact portion, the connecting 
member having a receiving hole for loosely receiving the end portion of 
the insulating resilient piece and the sheet end of the flexible printed 
circuit board together, the contact portion exposed in the receiving hole; 
and an actuating member for pressing the extension portion of the 
insulating resilient piece towards the rear surface of the flexible 
printed circuit board when the end portion of the insulating resilient 
piece and the sheet end of the flexible printed circuit board are received 
together in the receiving hole, whereby the conductor pattern of the 
flexible printed circuit board is pressed onto and is brought into contact 
with the contact portion. 
According to this invention, there is further provided a multi-row 
connector for establishing electric connection to a paired connector 
comprising contact rows of a plurality of contacts in each contact row, 
the multi-row connector comprising: a first insulator block having a sheet 
receiving hole; a pair of flexible contact sheets having individual front 
surface and individual sheet ends with rows of parallel conductor 
patterns, not less in number than the contacts in each contact row, 
arranged on each of the front surfaces to reach the sheet ends and with 
the flexible contact sheets received in the sheet receiving hole in a back 
to back opposing relation; a second insulator block having a sheet 
receiving groove for receiving the flexible contact sheets with the sheet 
ends protruded through the contact receiving groove; and an actuating 
member for actuating the flexible contact sheets to bring the parallel 
conductor patterns at the sheet ends near to the contacts after the second 
insulator block is brought into contact with the paired connector to place 
the parallel patterns near at the sheet ends to the contacts. The 
multi-row connector comprises: a pair of insulating resilient pieces 
having individual piece ends fixed to the sheet ends, respectively, and 
extended backwardly of the flexible contact sheet to have individual free 
ends spaced apart by a predetermined distance and to be placed in the 
sheet receiving groove; the actuating member having a first and a second 
diameter smaller than and greater than the predetermined distance, 
respectively, so as to be freely inserted between the free ends and to 
push the free ends apart when the actuating member is inserted between the 
free ends to be subsequently positioned between the free ends with the 
first and the second diameters directed substantially perpendicularly and 
parallel to the predetermined distance, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIGS. 1 through 3, exemplarily only depicted is a 
multi-connector 11 using, as a plurality of flexible contact sheets, a 
plurality of flexible printed circuit boards having a plurality of 
conductive patterns according to a first embodiment of this invention. The 
multi-row connector 11 is for establishing electric connection to a 
printed circuit board 13 or a paired or mating connector 15 used as a 
mother board. The paired connector 15 comprises an insulator block 16 and 
contact rows of a plurality of contacts 17 supported in the insulator 
block 16. Each of the contacts 17 has a contact portion and a terminal end 
connected to the circuit board as shown in FIGS. 2 and 3. 
The multi-row connector 11 comprises a first insulator block 19 having two 
sheet receiving slits 21 collectively as a sheet receiving hole. In the 
multi-row connector 11, a pair of insulating flexible contact sheets 23 
has individual front surface depicted in FIG. 1, one as seen and the other 
opposite to a direction of sight, and individual sheet ends depicted at 
bottom of the flexible contact sheets 23. It is possible as will be 
understood from the following to use a single flat flexible sheet as the 
flexible contact sheet 23. Rows of parallel conductor patterns 25 are 
arranged to reach the sheet ends on each of the front surfaces. The 
conductor patterns 25 are not less in number on each front surface than 
the contacts 17 in each contact row so that the contacts 17 of the contact 
rows may be brought into electric contact with the conductor patterns 25. 
The flexible contact sheets 23 are put in the sheet receiving hole 21 in a 
back to back opposing relation, as is clear in FIG. 1, with the sheet ends 
brought onto a common plane. 
In the multi-row connector 11, a second insulator block 27 has a sheet 
receiving groove 29 for receiving the flexible contact sheets 23 with the 
sheet ends protruded through the contact receiving groove 29. More 
specifically, the contact receiving groove 29 has a bottom end which is in 
contact in FIG. 3 with the paired connector 15. An actuating member 31 is 
for actuating the flexible contact sheets 23 to bring the parallel 
conductor patterns 25 at the sheet ends near to the contacts 17 after the 
second insulator block 27 is brought into contact with the paired 
connector 15 to place the conductor patterns 25 near at the sheet ends to 
the contacts 17. 
According to a salient feature of this invention, the multi-row connector 
11 comprises a pair of insulating resilient pieces 33 having individual 
piece ends fixed to the sheet ends of the flexible contact sheet 23, 
respectively, and extended backwardly of the flexible contact sheet 23 to 
have individual free ends or extension portions extending away from the 
rear surfaces to be spaced apart by a predetermined distance and to be 
placed in the sheet receiving groove 29. The actuating member 31 has a 
first and a second diameter smaller and greater than the predetermined 
distance so as to be freely inserted between the free ends and to push the 
free ends apart when the actuating member 31 is inserted between the free 
ends to be subsequently positioned between the free ends with the first 
and the second diameters directed substantially perpendicular and parallel 
to the predetermined distance. 
As best depicted in FIGS. 2 and 3, the first and the second insulator 
blocks 19 and 27 have side surfaces parallel to a direction of the 
opposing relation of the flexible contact sheets 23, namely, to a sheet of 
FIG. 2 or 3. The first and the second insulator blocks 19 and 27 have a 
member receiving hole 35 larger than a greater one of the first and the 
second diameters. After the first and the second insulator blocks 19 and 
27 are put together, the actuating member 31 is inserted through the 
member receiving hole 35 between the free ends of the insulating resilient 
pieces 33 with the first and the second diameters directed appropriately 
perpendicular and parallel (FIG. 2) to the predetermined distance. Later, 
the actuating member 31 is turned so that the first and the second 
diameters are directed substantially perpendicular and parallel (FIG. 3) 
to the predetermined distance. In this manner, the actuating member 31 
serves as an operating cam for insertion through the member receiving hole 
35. 
The paired connector 15 further has a receiving holes 18 for loosely 
receiving the sheet end of the flexible contact sheets 23 and the end 
portions of the insulating resilient pieces 33 together, the contact 
portions of the contacts 17 are exposed in the receiving holes 18. In the 
shown embodiment, each of contacts 17 is provided with each of the 
receiving holes 18. 
In FIG. 3, where the actuating member 31 is placed as the actuating cam 
between the free ends of the insulating resilient pieces 33 with the 
second or greater diameter directed parallel to the predetermined 
distance, three forces F1, F2, and F3 for the insulating resilient pieces 
33 having a longitudinal length L are related to one another in accordance 
with the following equations. 
EQU F1.times.L=F2.times.y 
and 
EQU F1.times.x=F3.times.y 
where 
EQU L=x+y 
Therefore, 
EQU F1=F2.times.y/L 
and 
EQU F1=F3.times.y/x. 
As a result, the force F1 becomes a minimal operating force by the use of 
the operating cam. 
Referring afresh to FIGS. 4 and 5, the description will proceed to a 
modification of the multi-row connector depicted in FIGS. 1 through 3. 
The multi-row connector 11 further comprise a cover member 37 for covering 
and receiving the first insulator block 19 on its top. The cover member 37 
has an insertion portion 39 protruding in the sheet receiving hole 21 to 
serve as the actuating member 31 when inserted between the free ends. The 
actuating member 31 of FIGS. 1 through 3 is no more separately necessary. 
Referring now to FIGS. 6 through 9 with FIGS. 1 through 3 again referred 
to, attention will be directed to a multi-row connector 11-1 according to 
a second embodiment of this invention. Similar parts are designated by 
like reference numerals. 
This multi-row connector 11-1 is for further connection to a daughter board 
41 having a pair of board surfaces of a predetermined thickness between 
the board surfaces. The daughter board 41 has a shim end 43 of the 
predetermined thickness downwardly in FIGS. 6 through 9. The predetermined 
thickness is not smaller than the predetermined distance. A plurality of 
conductive patterns 45 are formed on the board surfaces in correspondence 
to the conductor patterns 25. It is unnecessary that the conductive 
patterns 45 should reach a bottom end of the shim end 43. 
The first insulator block is divided into first primary and secondary 
insulator blocks 19-1 and 19-2 having a pair of sheet receiving holes 21-1 
and 21-2 collectively as the sheet receiving hole mentioned in connection 
with FIGS. 1 through 3 for individually receiving the flexible contact 
sheets 23. The shim end 43 serves as the actuating member 31. The flexible 
contact sheets are now two separate flexible contact sheets 23-1 and 23-2 
having tip ends, respectively. When pushed between the flexible contact 
sheets 23-1 and 23-2 downwardly of FIGS. 6 through 9, the daughter board 
41 tucks the flexible contact sheets 23-1 and 23-2 with the conductor 
patterns 25 brought into contact with the conductive patterns 45 since the 
flexible contact sheets 23-1 and 23-2 are easily bent to the the board 
surfaces. 
The shim end 43 comprises an engaging edge portion having flanges 47 
forwardly and backwardly protruded from the board surfaces, respectively, 
for engaging with the first insulator block 19 as best shown in FIG. 9. 
The first insulator block 19 has a shim end receiving opening between the 
first primary and the secondary insulator blocks 19-1 and 19-2. When the 
shim end 43 is put between the free ends, the flanges 47 abut the first 
insulator block 19. 
The second insulator block 27-1 has a pinhead receiving holes 49. The 
daughter board 41 has a pinbody receiving hole 51 for alignment with the 
pinhead receiving hole 49. An insertion pin 53 is inserted in the pinhead 
and the pinbody receiving holes 49 and 51 after the shim end 43 is put in 
the shim end receiving opening to bring the pinhead and the pinbody 
receiving holes 49 and 51 in alignment. The pin 53 is for preventing the 
first insulator block 19 from being inadvertently separated from the 
second insulator block 27. 
Referring to FIG. 10, an insulating resilient piece 33-1 may be divided 
into left and right resilient pieces 55-1 and 55-2 and a framework 57 if 
the free ends of the flexible contact sheets 23-1 and 23-2 are not stable 
in the sheet receiving groove 29 or 29-1. The resilient pieces 55-1 and 
55-2 are enclosed by the framework 57. Use of the frame work 57 increases 
mechanical strength of the insulating resilient pieces 33 described in 
conjunction with FIGS. 1 through 3. 
In the embodiment, this invention is described as regards a multi-row 
connector. However, it will be understood by those skilled in the art that 
the present invention can be applied for establishing an electrical 
connection between a flexible printed circuit board having a single or a 
plurality of conductor patterns and a connecting object such as a printed 
circuit board.