GB1594540A

GB1594540A - Electrical connection devices

Info

Publication number: GB1594540A
Application number: GB2238778A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-07-12
Filing date: 1978-05-25
Publication date: 1981-07-30
Also published as: CH623429A5; DE2827161C2; JPS5420393A; FR2397769A1; DE2827161A1; FR2397769B1; JPS6153835B2

Abstract

A connector comprises at least one elastic contact member (4) equipped with two successive branches (4e and 4f) which form between them an angle whose apex (4b) may be moved closer to or further away from a conducting track (3) under the action of a slide (6). The end (4c) of the contact member (4) terminates the branch (4e) and a slide (6), which can move in the direction of the arrow and in the opposite direction, acts on an anchoring part (4d) which comes after the intermediate branch (4f). Application: connectors for printed-circuit boards (2). <IMAGE>

Description

(54) IMPROVEMENTS IN ELECTRICAL CONNECTION DEVICES (71) I, FRANCOIS ROBERT BON HOMME, a French citizen, of 6, Parc de Bearn, 92210, Saint-Cloud, France, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to electrical connection devices for printed circuit boards.

More particularly, the invention relates to an electrical connection device for printed circuit boards, comprising a frame in which can be guided, in an insertion and extraction plane, a printed circuit board provided with conducting connection tracks on its two surfaces, the frame carrying resilient contact members each having a first end fixed with respect to said frame and an active region arranged, in a closed position of the contact member, to engage resiliently a respective one of the conducting connection tracks on a printed circuit board inserted into the frame, the frame also carrying a control mechanism operable to act on the resilient contact members alternately in a direction causing opening of the contacts and in a direction causing closing of the contacts, the control mechanism comprising a slide movable parallel to the insertion and extraction plane, each contact member comprising, between a hinge-forming portion and an anchoring portion fixed with respect to the slide, two portions approximately rectilinear at rest which are inclined to each other and to said plane and whose junction constitutes the active region of the contact member.

Such a connection device has been described in my U.K. patent specification No.

1,480,721. In this known connection device, it is the other end of each contact member which is anchored in the slide whilst its hinge-forming portion is comprised between this anchoring end and a portion which is fixedly held in the frame. In addition, the control mechanism comprises two slides which are symmetrical with one another with respect to the insertion and extraction plane.

In this known connection device, it is possible to draw on each contact member a deformable triangle of which two sides are constituted by its two approximately rectilinear portions and of which the third side, imaginary, connects the hinge-forming portion (a loop or single turn for example) to the anchoring end. The two first sides have an almost constant length, whilst the third or imaginary side has a variable length according to the position of the slide. In the open conditions of the contact, the slide occupies a position such that the imaginary side of the triangle has its maximum length and consequently, the height of the triangle measured from this imaginary side is minimal.

In other words, the apex of the triangle opposite this imaginary side (this apex constituting the active region of the contact member), is relatively close to the corresponding slide, that is to say relatively distant from the printed circuit board. If the slide is now moved in the desired direction, the latter thrusts against the anchoring end of the contact member, which shortens the imaginary side of the triangle and lengthens the height measured from this imaginary side.

The active region of the contact member then gradually approaches the board to come first into linear contact with the corresponding connection track, and then spread out while sliding on this track, which ensures self-cleaning of the contact regions. At the end of the movement of the slide, the active region of the contact member is bearing against the connection track with a force which depends, among other things, on the amplitude of movement of the slide. If the slide is now moved in the reverse direction, the latter pulls on the anchoring end of the contact member, which lengthens the imaginary side of the triangle and sets back the active region of the contact member in relation to the connection track. It is to be noted that the deformation of the contact member is caused only by the movement of the slide without bringing into play the resilience of the metal of the contact member.

Thus, as has been recalled above with respect to this known connector, it is one of the ends of each contact member which is anchored in the slide. Since the printed circuit board must be able to arrive beyond this end to reach the active region of the contact member, the slide can only be situated outside of the insertion and extraction plane and the control mechanism hence comprises necessarily two slides symmetrical with one another with respect to this plane and spaced from one another. The presence of these two slides necessarily increases the overall thickness of the connection device, which is troublesome for many applications.

It is an object of the invention to improve connection devices of the type set forth, so that they overcome certain drawbacks of known devices and in particular so that their thickness may be reduced.

According to this invention there is provided a connection device of the type set forth, wherein the hinge-forming portion of each contact member is constituted by a second end portion of the member and the anchoring portion of each contact member is separated from the second end portion by the two aprpoximately rectilinear inclined portions. By "second end portion" is meant here the end of the contact member which is opposite the "first end", fixed with respect to the frame.

Preferably, the connection device comprises a single slide which is symmetrical with respect to the insertion and extraction plane and to the two surfaces of which are fixed the anchoring portions of the contact members.

In a particularly advantageous embodiment, each contact member is constituted by a metal wire and the slide and/or the frame possess guide means which act on its approximately rectilinear portions so as to hold them constantly in the same plane. In this case, the hinge-forming end of the wire is, preferably, folded aprpoximately at rightangles with respect to the insertion and extraction plane, away from the latter, and is introduced into a hole formed for this purpose in the frame.

The distance which exists between the first end of each contact member, fixed with respect to the frame, and its anchoring portion varies necessarily according to the position of the slide. To take this fact into account, each contact member advantageously comprises, between its first end and its anchoring portion, a portion deformable in a plane perpendicular to the insertion and extraction plane. To avoid these deformable portions from touching in the course of the manipulations of the connection device, the slide is advantageously provided with an insulating plate lying in the insertion and extraction plane, in the region of the deformable por tions of the contact members.

Lastly, it is advantageous to arrange the control mechanism so that it comprises two sliding strips fast to one another and guided in translation with respect to the frame, these sliding strips being provided with oblique slots in which an axle fast to the slide is engaged and held so as to be movable only parallel to the translation movement of the slide. This construction helps to limit the overall thickness of the connection device.

The invention relates not only to the above-defined connection devices, but also to the contact members and slides designed to be incorporated in these connection devices.

The invention will now be described, by way of example, with the aid of the accompanying drawings.

Figure 1 of these drawings shows, in partial perspective, a connection device acording to the invention which is sectioned through a plane perpendicular to the insertion and extraction plane and passing through two opposite contact members.

Figure 2 shows, also in partial perspective, the same connection device which is sectioned through a plane parallel to the plane of section of Figure 1 and passing through one of the drive axles of the slide.

Figures 3, 4 and 5 illustrate successive phases of the closing movement of the contact members, by diagrammatic views in the plane of section of Figure 1.

The connection device according to the invention comprises a rectangular frame 1 of which there has only been shown, in Figures 1 and 2, one of the corners opposite the insertion side for printed circuit boards such as the board 2 of Figures 3 to 5. Such a board 2, which can be guided by the frame 1 in an insertion and extraction plane P, is provided with conducting connection tracks 3 on its two surfaces.

The frame 1 carries resilient contact members 4 of which a first end 4a is fixed with respect to the frame 1 and which are designed to touch respectively through an active region 4b, with a suitable resilient force, the conducting connection tracks 3 when the board 2 has been suitably inserted into the frame 1.

The frame 1 bears in addition a control mechanism 5 operable to act on the contact members 4 alternately in the direction of opening and closing. This control mechanism comprises a slide 6 movable in translation parallel to the insertion and extraction plane P, as indicated by a double arrow F in each of Figures 1 and 2.

Each contact member 4 comprises, between a hinge-forming portion 4c and an anchoring portion 4d fixed with respect to the slide 6, two approximately rectilinear portions 4e, 4f which are inclined to one another and with respect to the plane P and whose junction constitutes the active region 4b of the contact member 4.

In accordance with the invention, on each contact member 4, the hinge-forming portion 4c is constituted by the second end of this member 4 and the anchoring portion 4c, fixed with respect to the slide 6, is separated from this second end by the two inclined portions 4e and 4f.

Considering that the board 2 needs only to reach the level of the active region 4b, that is to say well before the anchoring portion 4d, it is possible to make the control mechanism 5 comprise a single slide 6 which is symmetrical with respect to the plane P and to the two surfaces of which the anchoring portions 4d of all the contact members 4 are fixed. Thus, as is to be seen from the drawings, each anchoring portion 4d may be constituted by z permanent deformation, of rectangular profile for example, which is housed in a recess formed locally in the slide 6. Such a recess is limited by partitions 7, perpendicular to the plane P and parallel to the double arrow F, which help to prevent the corresponding - contact member 4 from rotating on itself and to insulate the anchoring portions 4d electrically from one another. These recesses are preferably arranged in pairs in the same plane, such as the plane of section of Figure 1.

Each contact member 4 is constituted by a metal wire and the slide 6 and/or the frame 1 possess guide means which act on its approximately rectilinear portions 4e, 4f so as to help, with the above-said partitions 7, to keep said portions constantly in the same plane, that is to say to prevent the contact member concerned 4 from rotating on itself.

In the embodiment shown, these guide means are constituted by partitions 8 which are borne by two parallel and opposite walls 9a and 9c of the frame 1. These partitions 8 could moreover be replaced or completed by similar partitions, carried by the slide 6. To facilitate the assembly of the connection device, the walls 9a and 9c and the bottom 9b of the frame 1 are constituted by separate parts, fixed together for example, by means of screws (not shown). In addition, the frame 1 may be provided, on its lateral surface, with an opening 19 enabling the insertion and extraction of the board 2 through this surface.

The hinge-forming portion or end 4c is folded at aproximately right-angles with respect to the plane P, away from the latter, and it is inserted into a hole 10 formed for this purpose in the walls 9a or 9c of the frame 1.

As is shown by Figures 1 and 2, the holes 10 pass through the walls 9a and 9c from side to side which enables the ends 4c to be immobilised either by folding them at the exit from these holes, or by introducing an adhesive material into the holes 10 through the outer surface of the walls 9a and 9c. To facilitate the self-cleaning of the active regions 4b of the conducting connection tracks 3, it is advantageous to give that portion 4e, depending from the hinge-forming portion 4c, a greater length than that portion 4f, depending from the anchoring portion 4d so that the portion 4e is deformed preferentially with respect to the portion 4f.

Each contact member 4 comprises, between its first end 4a and its anchoring portion 4d, a portion 4g adapted to be deformed in a plane perpendicular to the insertion and extraction plane P. This portion 4g may be constituted for example by a circular arc, of variable radius (see Figures 3 to 5), or by two approximately rectilinear successive portions (see Figure 1). As is to be seen from Figure 1, the slide 6 is advantageously provided with an insulating plate 11 lying in the plane P, at the level of the deformable portion 4g of the contact members 4. Transverse partitions 12 may be formed on both sides of this plate 11 to guide the portions 4g in the course of their deformation and to insulate them electrically from one another.

As can be seen from Figures 1 and 2, the control mechanism 5 comprises two sliding strips 13, parallel to the length of the slide 6, which are fastened at their two ends by transverse members 14. These sliding strips 13 are housed in grooves 15 formed in the walls 9a, 9c of the frame 1 and open towards the outside of the latter, which grooves 15 guide the sliding strips 13 in translation.

The latter are provided with oblique slots 16 which receive, in pairs, an axle 17 fast to the slide 6. The axle 17 passes through each wall 9a and 9c of the frame 1, in the region of its groove 15, through a transverse slot 18 so that this axle 17 is held so as to be only movable parallel to the translation movement of the slide 6 (double arrow F). Thus as can be seen from Figure 1 (to the left), the presence of this axle 17 prevents contact members 4 from being placed in the same region as this axle. This is the reason why the rows of holes 10 and partitions 8 show a gap at this level.

The slide 6 is arranged to slide in contact with the inner surface of the walls 9a, 9c and it is provided with notches which enable the contact members 4 to enter the recesses bounded by the partitions 7 and to emerge therefrom.

A connection device is thus obtained which is assembled and operates in the following manner.

The assembly comprises the steps of: placing the contact members 4 on the slide 6 and through the bottom 9b, the fixed ends 4a passing through this bottom 9b; positiqning of the walls 9a and 9c; and fixing the three parts 9a, 9b and 9c of the frame 1 by a mechanical method (screws) or again by ultrasonic welding.

In the position shown in Figures 1, 2 and 3, each axle 17 (one at each end of the slide 6) is to be found at that end of a pair of slots 16 which causes the slide 6 to occupy its rightmost position. Consequently, the angle formed by the approximately rectilinear portions 4e, 4f of each contact mem bey 4, is very obtuse and all the active portions 4b are kept away from the space swept by a board such as 2. It is hence possible to insert this board 2 in the frame 1 under zero insertion force conditions, that is to say without the active regions 4b rubbing on the conducting tracks 3 of the board 2. Once the latter is placed in position in the frame 1, the operator can actuate the control mechanism 5 so as to advance the sliding strips 13. By traversing the slots 16 and 18, each axle 17 is hence moved to the left of the drawings, from the position of Figure 3 to that of Figure 5. In Figure 4, the active regions 4b come into contact with the conducting connection tracks 3. Then, from the position of Figure 4 to that of Figure 5, the active regions 4b sweep over the tracks 3 from left to right. In fact, those portions 4e, which are the longest and consequently the most flexible, tend to be deformed whilst the portions 4f tend to accompany the movement of the slide 6 practically without being deformed. Such a self-cleaning effect has been described in detail in my U.K. patent specification No. 1,480,721.

When the sliding strips 13 are then moved in the reverse direction, the elements of the device are moved or deformed in reverse order to resume eventually the positions shown in Figures 1 to 3. It is then possible to withdraw the board 2 to check it or to replace it by another.

Thus as can be seen from Figures 1 and 2, the connection device according to the invention has a small overall thickness which is equal to the sum of the thicknesses of the single slide 6 and of the two walls 9a and 9c of the frame 1, the presence of the grooves 15 enabling the sliding strips 13 to be accommodated within the thickness of the walls 9a and 9c.

The invention is not limited to the embodi- ment which has just been described with reference to the accompanying drawings.

Thus the contact member 4 could be constituted by a metal strip and not by a metal wire. Moreover, in order that portion 4e may be deformed preferentially with respect to the portion 4f, if it is possible to act not on the respective lengths of these portions but on their respective thicknesses or on the orientation of their profile, in the manner indicated in my U.K. patent specificatlon No.

1,498,611.

WHAT I CLAIM IS: 1. An electrical connection device for printed circuit boards, comprising a frame in which can be guided, in an insertion and ex-: traction plane, a printed circuit board pro vided with conducting connection tracks on its two surfaces, the frame carrying resilient contact members each having a first end fixed with respect to said frame and -an active region arranged, in a closed position of the contact member, to engage resiliently a res pective one of the conducting connection tracks on a printed circuit board inserted into the frame, the frame also carrying a control mechanism operable to act on the resilient contact members alternately in a direction causing opening of the contacts and in a direction causing closing of the contacts, the control mechanism comprising a slide mov able parallel to the insertion and extraction plane, each contact member comprising, be tween a hinge-forming portion and an anchoring portion fixed with respect to the slide, two portions approximately rectilinear at rest which are inclined to each other and to said plane and whose junction constitutes the active region of the contact member, wherein the hinge-forming portion of each contact member is constituted by a second end portion of the member and the anchoring portion of each contact member is separated from the second end portion by the two approximately rectilinear inclined portions.

2. A connection device as claimed in Claim 1, characterised in that it comprises a single slide which is symmetrical with respect to the insertion and extraction plane and with respect to two planes containing the anchor ing portions of all the contact members.

3. A connection device as claimed in Claim 2, characterised in that each contact member is constituted by a metal wire and the slide and/or the frame possess guide means which act on its approximately rectilinear portions so as to keep them constantly in the same plane.

4. A connection device as claimed in Claim 3, characterised in that the hinge-forming end of the wire is folded approximately at right angles with respect to the insertion and ex traction plane, away from the latter, and inserted in a hole formed for this purpose in the frame.

5. A connection device as claimed in any one of Claims 2 to 4, characterised in that each contact member comprises, between its first end and its anchoring portion, a portion deformable in a plane perpendicular to the insertion and extraction plane.

6. A connection device as claimed in Claim -5, characterised in that the slide is provided with an insulating plate situated in the in sertion and extraction plane, in the region of the deformable portions of the contact members.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. fixing the three parts 9a, 9b and 9c of the frame 1 by a mechanical method (screws) or again by ultrasonic welding. In the position shown in Figures 1, 2 and 3, each axle 17 (one at each end of the slide 6) is to be found at that end of a pair of slots 16 which causes the slide 6 to occupy its rightmost position. Consequently, the angle formed by the approximately rectilinear portions 4e, 4f of each contact mem bey 4, is very obtuse and all the active portions 4b are kept away from the space swept by a board such as 2. It is hence possible to insert this board 2 in the frame 1 under zero insertion force conditions, that is to say without the active regions 4b rubbing on the conducting tracks 3 of the board 2. Once the latter is placed in position in the frame 1, the operator can actuate the control mechanism 5 so as to advance the sliding strips 13. By traversing the slots 16 and 18, each axle 17 is hence moved to the left of the drawings, from the position of Figure 3 to that of Figure 5. In Figure 4, the active regions 4b come into contact with the conducting connection tracks 3. Then, from the position of Figure 4 to that of Figure 5, the active regions 4b sweep over the tracks 3 from left to right. In fact, those portions 4e, which are the longest and consequently the most flexible, tend to be deformed whilst the portions 4f tend to accompany the movement of the slide 6 practically without being deformed. Such a self-cleaning effect has been described in detail in my U.K. patent specification No. 1,480,721. When the sliding strips 13 are then moved in the reverse direction, the elements of the device are moved or deformed in reverse order to resume eventually the positions shown in Figures 1 to 3. It is then possible to withdraw the board 2 to check it or to replace it by another. Thus as can be seen from Figures 1 and 2, the connection device according to the invention has a small overall thickness which is equal to the sum of the thicknesses of the single slide 6 and of the two walls 9a and 9c of the frame 1, the presence of the grooves 15 enabling the sliding strips 13 to be accommodated within the thickness of the walls 9a and 9c. The invention is not limited to the embodi- ment which has just been described with reference to the accompanying drawings. Thus the contact member 4 could be constituted by a metal strip and not by a metal wire. Moreover, in order that portion 4e may be deformed preferentially with respect to the portion 4f, if it is possible to act not on the respective lengths of these portions but on their respective thicknesses or on the orientation of their profile, in the manner indicated in my U.K. patent specificatlon No. 1,498,611. WHAT I CLAIM IS:

1. An electrical connection device for printed circuit boards, comprising a frame in which can be guided, in an insertion and ex-: traction plane, a printed circuit board pro vided with conducting connection tracks on its two surfaces, the frame carrying resilient contact members each having a first end fixed with respect to said frame and -an active region arranged, in a closed position of the contact member, to engage resiliently a res pective one of the conducting connection tracks on a printed circuit board inserted into the frame, the frame also carrying a control mechanism operable to act on the resilient contact members alternately in a direction causing opening of the contacts and in a direction causing closing of the contacts, the control mechanism comprising a slide mov able parallel to the insertion and extraction plane, each contact member comprising, be tween a hinge-forming portion and an anchoring portion fixed with respect to the slide, two portions approximately rectilinear at rest which are inclined to each other and to said plane and whose junction constitutes the active region of the contact member, wherein the hinge-forming portion of each contact member is constituted by a second end portion of the member and the anchoring portion of each contact member is separated from the second end portion by the two approximately rectilinear inclined portions.

7. A connection device as claimed in any

one of Claims 1 to 6, characterised in that the control mechanism comprises two sliding strips fastened to one another and guided in translation with respect to the frame, these sliding strips being provided with oblique slots in which an axle fast to the slide is engaged and held so as to be movable only parallel to the translation movement of the slide.

8. An electrical connection device for printed circuit boards, constructed, adapted and arranged to operate substantially as described with reference to, and as shown in, Figures 1 to 5 of the accompanying drawings.