EP0294433B1

EP0294433B1 - Filtered electrical device and method for making same

Info

Publication number: EP0294433B1
Application number: EP88900408A
Authority: EP
Inventors: Douglas James Pirc
Original assignee: Whitaker LLC
Current assignee: TE Connectivity Corp
Priority date: 1986-12-24
Filing date: 1987-11-27
Publication date: 1993-03-10
Anticipated expiration: 2007-11-27
Also published as: DE3784711D1; DE3784711T2; WO1988005218A1; JPH01501983A; EP0294433A1; JP2585777B2

Abstract

A filtered electrical device (10) for being secured externally to an electrical article such as an electrical connector and electrically engageable to circuit paths thereof comprises a plurality of contact members (12), a housing member (40) having a plurality of filter receiving apertures (48) therein, a plurality of filter members (54) disposed in the apertures (48) and electrically connected to the contact members (12) and a ground means. The contact members (12) have first and second contact portions (14, 24), the first contact portions (14) being secured in the housing (40) and engageable with corresponding contact sections of the electrical article to which the filtering device (10) is secured. The second contact portions (24) are exposed along a bottom surface (50) of respective apertures (48) and are paired with and spaced from third contact portions (30) which are also exposed along a bottom aperture surface (50). Ground means include a bus means (34) secured in the housing (40) and extending outwardly from third contact sections (30). Filter members (54) are electrically engaged to respective pairs of second and third contact portions (14, 24). The device (10) can be manufactured in a continuous form by stamping a series of contact means in a strip (58) of metal, insert molding housing member (40) the desired length around a plurality of the contact means (70) to form a series of severable lead frames (60), placing filter members (54) in the filter receiving apertures (48), and severing individual devices (10). Alternatively, the strip of devices (10) can be stored in reel form until they are to be used.

Description

This invention relates to electrical connectors and more particularly to filtered electrical connectors and filtering devices for providing protection against electromagnetic interference and radio frequency interference.
Electrical circuitry often must be protected from disruptions caused by electromagnetic interference (EMI) and radio frequency interference (RFI) entering the system.
In addition to protecting electronic equipment against EMI/RFI energy, there is also a need to protect the equipment against power surges owing to electrostatic discharges (ESD) and electromagnetic pulse (EMP). The high voltage generated by ESD and EMP can damage voltage sensitive integrated circuits and the like.
Frequently today's electronic circuitry requires the use of high density, multiple contact electrical connectors. There are many applications in which it is desirable to provide a connector with a filtering capability, for example, to suppress EMI and RFI. To retain the convenience and flexibility of the connector, however, it is desirable that the filtering capability be incorporated into connectors in a manner that will permit full interchangeability between the connectors and their unfiltered counterparts. In particular, any filter connector should also in many instances retain substantially the same dimensions as the unfiltered version and should have the same contact arrangement so that either can be connected to an appropriate mating connector. Additionally, it is sometimes desirable to filter only certain lines within a connector and to use the same basic connector in a number of applications, each requiring different selected lines to be filtered.
One means to protect against undesirable interference without altering the internal structure of a connector is by the use of shielding. The shielding may take several forms. For adequate protection, it is essential, however, that there be no break in continuity of the shielding.
Other means for protecting against interference include the use of internal filtering schemes which include the use of filter sleeves and planar filter members. Both of these methods generally require the additional space within the connector to accommodate the sleeves or other filtering devices. Furthermore, connectors of this type often include a number of labor-intensive steps during the manufacture of the connectors. These connectors are not readily manufacturable by automatic equipment.
In many instances it is desirable to have an external filtering device that is an "add-on" device to provide filtering to an already existing non-filtered connector. This is particularly desirable in instances when the same basic connector may be used in a number of different applications, each requiring filtering of different lines in the connector. It is also desirable that a method be found that will lend itself to automation of the assembly line by robotic devices and the like that will enable filtered connectors to be manufactured on a more cost effective manner.
In accordance with the present invention, an electrical component is provided which can be secured to an electrical article such as an electrical connector, the component being engageable to circuit paths of the article to provide filtering for those circuit paths. The electrical component is comprised of a dielectric housing member having a plurality of contact members secured therein and housing a plurality of filter receiving apertures along a first face thereof. The contact members
There is disclosed in US-A-4 580 866, an electrical component for being secured to an electrical article and being electrically engageable with circuit paths thereof for filtering the circuit paths, the component including housing means having filter receiving aperture means extending along a face thereof and having filter means disposed therein, the aperture means further including contact portions for engaging respective signal and ground circuit paths of the filter means.
This known electrical component has apertures extending therethrough for receiving mating terminals of a pair of electrical connectors so that these terminals are electrically connected to said filter means.
An electrical component according to the present invention, for being secured to an electrical article and being electrically engageable with circuit paths thereof for filtering the circuit paths, is characterized in that a plurality of contact members are secured to the housing means along a side thereof, the contact members have first and second contact portions, the first contact portions extending outwardly from a first side of the housing means and being electrically engageable with corresponding contact sections of the circuit paths of the electrical article, the second contact portions extending into the filter receiving aperture means and being exposed therein; for electrical engagement with corresponding signal paths of respective filter means; third contact portions are paired with the second contact portions and are spaced therefrom, the third contact portions extending into the filter receiving aperture means and being exposed therein for electrical engagement with corresponding ground paths of respective filter means, the filter means being disposed in the filtering aperture means such that the signal and ground paths are electrically joined to selected pairs of associated second and third contact portions; bus means is secured in the housing means and extends from the third contact portions, the bus means being adapted to be engaged by and secured to said grounding means; and connecting means on first contact portions electrically connect and mechanically secure said first contact portions to contact sections of electrical article; whereby when said first contact portions are engaged with respective circuit paths of said electrical article and said bus means is engaged to said grounding means, said filter means provide filtering protection for said electrical article.
The electrical component can be connected to an associated electrical article by electrically engaging the first contact portions to respective circuit paths of the electrical article and the bus means to a grounding means for the article, the housing member of the component. In the preferred embodiment,the housing member of the electrical component is secured to an external surface of the electrical article.
It is an object of the present invention to provide electrical filtering means that can be externally mounted to an electrical connector or other electrical article.
It is another object of the invention to provide a filtering device that can be added on to an existing unfiltered connector.
It is a further object of the invention to provide an external filtering device that lends itself to automated assembly procedures.
It is another object of the invention to provide a filtering device which can be manufactured in a continuous strip.
Another object of the invention is to provide a method for manufacturing a filter device that may be used to retrofit existing connectors.
Furthermore, it is an object of the invention to provide a device for filtering connectors wherein the filtering device may be included on selective circuit paths.
A method according to the present invention, of making an electrical component according to the present invention is defined in claim 10.
Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a perspective view of the electrical device of the present invention;
Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1 with parts exploded therefrom;
Figure 3 illustrates the steps in a continuous process for making the device in accordance with the present invention;
Figure 4 is a perspective assembled view of an electrical connector assembly having the device of the present invention attached thereto;
Figure 5 is an exploded perspective view of the connector assembly of Figure 3;
Figure 6 is a plan view of a strip of alternative embodiment of contact members;
Figure 7 is a fragmentary perspective view illustrating an alternative embodiment of the device having contact members of Figure 6;
Figure 8 shows the device of Figure 7 used in an interconnection system between two electrical connectors;
Figure 9 is a perspective view of the assembled electrical connector of Figure 8;
Figure 10 is a perspective view showing a further alternative embodiment of the device of the invention mounted to an electrical connector;
Figure 10A is a cross-sectional view of the device of Figure 10;
Figure 11 shows another alternative embodiment of the device mounted to a printed circuit board; and
Figure 11A is a cross-sectional view of the device of Figure 11.

Referring now to Figures 1, 2 and 3, a filtering device 10 is designed to be used with an electrical article to provide filtering for selected circuit paths of the articles. Device or component 10 is comprised of a plurality of contact members 12, a dielectric housing member 40, and filter members 54. Contact members 12 have first and second contact portions 14 and 24 respectively. First contact portions 14 are engageable with corresponding contact portions of an electrical article. First contact portions 14 are secured in the housing member 40. Dielectric housing member 40 includes a plurality of filter receiving apertures 48 along a first face 42 thereof. Second contact portions 24 are exposed along a bottom surface 50 of respective apertures 48. Third contact portions 30 are paired with second contact portions 24 and are spaced therefrom at 28. Third contact portions 30 are also exposed along the bottom surface 50 of respective filter receiving apertures 48. Bus means 34 is secured in housing member 40, said bus means 34 extending outwardly from the third contact portion 30 and being adapted to be engaged by grounding means on an electrical article. A plurality of filter members 54 are disposed in respective filter receiving apertures 48 of housing member 40 and electrically joined to respective pairs of second contact portions 24 and third contact portions 30. Filter members 54 are surface mounted components, such as chip capacitors, resistors, unipolar or bipolar diodes, or the like. First contact portions 14 further have connecting means 18 having aperture 20 therein for electrically connecting first contact portion 14 corresponding contact members of an electrical article as explained below.
As illustrated in Figure 3, electrical device 10 preferably is made in continuous form by stamping and forming a plurality of lead frames 60 in strip 58 of suitable flat stock metal such as copper, phosbronze, or the like as known in the art. Strip 58 is first stamped to form first and second carrier strips 62, 66 having a plurality of essentially parallel cross bar members or contact means 70 extending between carrier strips 62, 66 as is shown in Frame A. Cross bar members 70 become contact member sections 14, 24 and 30 in the assembled device. Carrier strips 62, 66 have apertures 64 and 68 therein which are used for aligning strip 58 in the manufacturing and assembly process. If desired, cross bar members 70 may be plated on the desired contact area.
Housing members 40 are then insert molded around portions of the stamped members, each housing encompassing the desired number of cross bar members. A plurality of filter receiving apertures 48 are also formed, one aperture 48 being associated with each cross bar member 70 within housing 40. In the preferred embodiment, housing members 40 are located and molded on strip 58 such that carrier strip 66 becomes bus bar 34 of severed device 10. The material used for molding the housings is preferably one that will withstand the temperatures associated with vapor flow soldering techniques. One preferred material is polyphenylene sulfide, available from Phillips Petroleum Co. under the trade name Ryton^R. Other suitable materials are known in the art.
As is shown in Frame B, cross bar members 76 extend completely across apertures 48. In the next stage of manufacturing, shown in Frames C and D, a portion of cross bar members 70 is removed at 74 to form the three contact portions 14, 24 and 30 of device 10. Concomitantly, a portion of underlying dielectric housing material is also removed. Carrier strip 62 may be removed at the same time or during a subsequent step. It is to be understood that cross bar members 70 may be separated prior to insert molding, if desired, and that cross bar members 70 between adjacent housing members 40 may be severed at this time or when individual devices 10 are severed from the strip. First contact portions 14 are then bent and formed. Lastly, filter members 54 are mounted and preferably soldered in their respective apertures.
As shown in Frame F of Figure 3, filtered devices 10 can be completely formed on the strip while remaining attached to carrier strip 66. The strip of filter devices can be rolled onto a reel (not shown) until device 10 is ready to be assembled to an electrical article. Individual devices 10 can be severed at 59 from the strip as needed. As shown in Figure 3, carrier strip 66 becomes bus bar 34.
The process for making device 10 lends itself to automation since strip 58 may be stamped and formed, rolled on a reel (not shown), and later formed into electrical devices 10 in accordance with the invention. The length of housing member 40 and the number of contact members 12 therein is determined at the time of molding and strip 58 is stamped such that a plurality of differing length housing members 40 can be molded. In general, the molding machine can be programmed to index a selected number of cross bar members 70. Once housing members 40 have been molded, the strip is moved to a stamping station to stamp and form the device of the desired configuration. Insertion of the filter members 54 lends itself to pick and place robotic systems. The well-defined apertures 48 can be aligned so that the equipment can place filter members 54 between the second and third contact portions 24 and 30 at selected locations.
Figures 4 and 5 illustrate the use of device 10 with electrical connector 80 comprised of dielectric housing member 82 having a plurality of apertures 84 extending therethrough, a plurality of electrical terminal members 86 disposed in respective apertures 84, and conductive ground shell means 90. Terminal members 86 have terminal post sections 88 extending rearwardly of housing member 82. Device 10, in accordance with the preferred embodiment, has a generally rectangular housing member 40 having a plurality of filter members 54 preferably extending slightly outwardly from a plurality of filter receiving apertures 48. First contact portions 14 are bent at right angles so that device 10 can be mounted to an electrical connector housing 82 with each of the first contact portions 14 engaged with respective terminal posts 88. Bus bar 34 extends from the opposite side of the housing and is designed to be engaged with a ground plane of the connector 80. In the example shown, filter device 10 is mounted on the surface of the connector housing 82 such that bus bar 34 can be electrically connected to ground shell means 90 by solder. Apertures 20 in the first section of contact member 12 engage respective terminal post sections 88 of connector 80 and are soldered thereto. It is to be understood that this electrical connector is merely a representative sample of the types of connector with which this device may be used. It is to be further understood that other pin or socket terminals may also be used.
Connector 80 as disclosed in Figures 4 and 5 has two rows of terminal members. It is, therefore, necessary to use two electrical devices 10 in accordance with the invention, one device being mounted to each side of connector housing 82, with first contact portions 14 of each device 10 electrically connected to only one row of the terminal posts 88 and respective bus bars 34 soldered to ground shell 90.
Figures 6 and 7 show an alternative embodiment 158 of stamped metal strip for forming lead frames for device 110. In this embodiment, the portion of cross bar member 170 that will become first contact portion 114 further includes a slot 122 having an enlarged portion 123 for receiving an insulated wire and a narrower portion 125 for piercing the insulated wire as can best be seen in Figure 7. In the assembled device, slot 122 is located in first contact portion 114 between aperture 120 which receives terminal posts 88 and housing 140. Carrier strip 162 is severed to form bus bar 134, which extends from third contact portion 130. Otherwise, device 110 is formed in the same manner as device 10 and is mounted to a connector in the same manner as previously described.
Figures 8 to 9 illustrate electrical connector assembly 300 in which filtering device 110 is used as an interconnecting means to interconnect selected lines of a first connector 180 to lines of a second connector 280. Connector assembly 300 is comprised of first and second dielectric shell members 301, 302, a first connector 180, filtering devices 110 secured to first connector 180, and a second connector 280. Selected terminal posts 192 of said first connector 180 are interconnected through filtering device 110 to lines 292 of the second connector. First connector 180 has the same general structure as connector 80 shown in Figures 4 and 5 and previously described. The difference between connector 80 and 180 is that filtering device 110 contains the lead frame embodiment of Figure 6 wherein the first contact section 114 includes the wire terminating slot 122 as best seen in Figure 7. Second connector 280 is comprised of a dielectric housing member 282 having a plurality of passageways 284 therethrough in which are disposed a plurality of terminal members (not shown). The terminal members are terminated to one end from conductor wire members 294 which extend rearwardly of housing member 282.
By terminating the other ends of wire members 294 in selected insulation displacement slots 122 of the first contact portions, selected lines of first and second connectors 180, 280 can be interconnected. After the wires 294 have been terminated to the desired lines of connector 180, first and second connectors 180, 280 are encased in shell members 301, 302. In the representative embodiment shown in Figure 8, shell members 301 and 302 are profiled to accept a modular plug 305 which will mate with connector 280. First and second shell members 301, 302 are secured together by means of snap features 311 molded into the shell members. Jack screws 306 are used to attach connector 300 to a complementary connector (not shown). Figure 9 shows the completed compact package containing the two connectors and a modular plug 305 connected to cable 307 inserted into back 308 of connector assembly 300. Connector assembly 300 provides a relatively compact package and means for filtering an existing connector and for selectively filtering the interconnection between two connectors while maintaining the mating configuration of both connectors.
Figures 10 and 10A illustrate another connector 380, in this instance a modular jack, having alternative embodiment 210 of the filtering device of the present invention mounted to the back thereof. In this embodiment, first contact sections 214 are spring loaded against corresponding terminal members (not shown) of connector 380. The terminal members lie within respective passageways 384 in connector housing 382. Owing to the close spacing of contact sections 214 in terminal passageways 384, adjacent apertures 248 having filter members 254 therein are staggered in housing member 240. Grounding of filter device 210 is achieved through ground leg members 98 which extend from the lower end of device 210 and engage circuit conductors on circuit board 99 as can best be seen in the cross-sectional view of Figure 10A. In this version, the sides of housing member 240 are expanded to snap fit onto the back of the modular jack. Figures 11 and 11A show a filter device 310 made in accordance with the invention for mounting directly to a circuit board 101 wherein the first contact sections 312 engage apertures 103 in the circuit board 101, apertures 103 being electrically connected to a circuit path 105 with which a further electrical connector may be engaged. Filter members 354 are placed in staggered apertures 348 owing to space limitations. The bus bar in this device is also connected to ground through leads 107 as shown in Figure 11.
It is to be understood that the electrical connectors used with the present device are representative samples only. It is to be further understood that frame and shape and types of connectors with which this device may be used are numerous. By filtering electrical connectors with an externally mounted filtering device, it is possible to selectively filter lines by omitting filter members from the various apertures. This allows the same basic connector to be filtered readily, in a variety of configurations and in a cost-effective manner. By making a filtered device in accordance with this manner, the filtering device lends itself to cost-effective manufacturing process which includes automatic equipment such as pick and place robots. Lead frame technology and insert molding lend themselves to continued automated manufacturing process which minimizes handling of the device as well as time and labor. The device uses small filtered capacitors, transient suppression diodes, resistors, or other components that are designed to be in parallel with the circuit, between pin and ground. The components used for any one connector need not be identical and selected frequencies may be controlled by placing filter devices of varying capabilities at selected locations. The filter device of the present invention is designed for filtering in the lower frequency ranges, preferably not to exceed 500 megahertz.

Claims

An electrical component (10) for being secured to an electrical article and being electrically engageable with circuit paths thereof for filtering the circuit paths, the component including housing means (40) having filter receiving aperture means (48) extending along a face thereof and having filter means (54) disposed therein, the aperture means further including contact portions for engaging respective signal and ground circuit paths of the filter means, the electrical component (10) being characterized in that;
a plurality of contact members (12) are secured to the housing means ( 40) along a side thereof, the contact members have first and second contact portions (14,24), the first contact portions (14) extending outwardly from a first side of the housing means ( 40) and being electrically engageable with corresponding contact sections of the circuit paths of the electrical article, the second contact portions (24) extending into the filter receiving aperture means (48) and being exposed therein, for electrical engagement with corresponding signal paths of respective filter means (54);
third contact portions (30) are paired with the second contact portions (24) and are spaced therefrom, the third contact portions (30) extending into the filter receiving aperture means (48) and being exposed therein for electrical engagement with corresponding ground paths of respective filter means (54), the filter means (54) being disposed in the filtering aperture means (48) such that the signal and ground paths are electrically joined to selected pairs of associated second and third contact portions (24,30);
bus means (34) is secured in the housing means (40) and extends from the third contact portions (30), the bus means (34) being adapted to be engaged by and secured to said grounding means; and in that
connecting means (20) on first contact portions (14) electrically connect and mechanically secure said first contact portions (14) to contact sections of the electrical article; whereby
when said first contact portions (14) are engaged with respective circuit paths of said electrical article and said bus means (34) is engaged to said grounding means, said filter means (54) provide filtering protection for said electrical article.
An electrical component as claimed in claim 1, characterized in that the filter receiving aperture means (48) includes a plurality of discrete apertures (50), each one configured to receive a filter means (54) therein, the second contact portions (30) being exposed along a bottom of the filter receiving aperture means (48).
An electrical component (10) as claimed in any one of the preceding claims, characterized in that said filter means (54) is surface mounted to said selected pairs of said second and third contact portions (24,30).
An electrical component (10) as claimed in claim 2, characterized in that said discrete filter receiving apertures (50), each have one pair of associated second and third contact sections (24,30) therein.
An electrical component (10) as claimed in any one of the preceding claims, characterized in that said bus means (34) is secured to and extends outwardly from said housing means (40) along a second side thereof, said second side being opposed to said first side.
An electrical component as claimed in any one of the preceding claims, characterized in that each of said first contact portions (14) of said electrical component includes an aperture (20) therein for receiving contact members of said electrical article.
The electrical component as claimed in claim 1, 2 or 3, characterized in that said first contact portions (14) of said electrical component are adapted to receive conductor means (294) electrically engaging circuit paths of an electrical connector (180); and in that selected circuit paths of said electrical connector can be interconnected to selected circuit paths of another electrical connector (280) to provide filtering for such interconnected paths while maintaining the mating configuration of the two electrical connectors (180,280).
An electrical component (110) as claimed in claim 1, characterized in that it is arranged in combination with first and second electrical connectors (180,280) so as to interconnect and selectively filter selected circuit paths of said electrical connectors (180,280), while maintaining the mating configuration of both connectors (180,280), the first and second connectors having first and second terminal members therein, said first contact portions (114) of the electrical component (110) being electrically engaged with corresponding terminal members (88) of the first electrical connector (180), the bus means (34) of said component (110) being connected to grounding means of said first electrical connector (180), means electrically connecting selected ones of said first portions (114) of the electrical component (110) to terminal members of the second electrical connector (280), the electrical component (110) being mounted on an exterior surface of the first connector (180).
A method of making electrical components (10) as claimed in claim 1, said method comprising the steps of:
providing first and second elongate, essentially parallel carrier strip members (62,66) having a plurality of essentially parallel cross bar members (70) extending transversely therebetween, defining a plurality of lead frames (60), each lead frame (60) comprising a group of said cross bar members (70) to be processed into the first and second contact portions (14,24) of said components (10), and the carrier strip members (62,66) extending between those cross bar members (70), said cross bar members (70) each having a first, an intermediate and a second section;
moulding dielectric housing means (40) over the intermediate section of each of said cross bar members (70) of said lead frames (60), each said housing means (40) being so molded that the intermediate sections of the cross bar members extend between, and the first and second sections of said cross bar members extend outwardly from the major sides of said housing means (40), the first sections of said cross bar members extending substantially outwardly from said housing means (40), said second sections of said cross bar members (70) extending but a slight distance to said second carrier strip (66) so that said second carrier strip (66) lies proximately adjacent to said second major side of said housing means (40), filter receiving aperture means (48) being formed in each of said housing means (40) such that said intermediate sections of cross bar members extend across said aperture means (48); severing said intermediate sections so that they define pairs of said second and third contact portions (24,30) and severing said first sections of said cross-bar members (70) from said first carrier strip member (62), so that they define said first contact portions (14);
disposing filter means (54) in said filter receiving aperture means (48) in electrical engagement with selected pairs of said second and third contact portions (24,30), said third contact portions (30) extending to said second sections of said cross bar members (70) and thereby to said second carrier strip (66); and severing the electrical component (10) so provided and the section of the second carrier strip member (66) associated with such component (10) from the remainder of the second carrier strip member (66) so that said severed second carrier strip member section forms the common bus means (34) of said component (10), outside the housing means (40) of said component (10).