Disengageable Electrical Connector

Abstract

Disengageable connector assembly comprises one connector part having channel shaped female pins therein and second connector part having male spring contacts which are adapted to move between the sidewalls of the channels. Channel contacts extend beyond the mating face of the one connector part and spring contacts are recessed in cavities in the second connector part.

Description

BACKGROUND OF THE INVENTION

The increasing use of extremely small electronic devices is producing an increasing demand for multi-contact connecting devices of very small size. For example, it is common practice to design printed circuit daughter boards having conductors extending to one edge of the board which are spaced apart by a distance of 0.050 inch. There are only a few commercially available multi-contact electrical connectors which can be used on circuit boards having this extremely close conductor spacing and the available connectors suffer from several comparative shortcomings. For example, some types of available connectors cannot be made in lengths of more than about two inches so that the number of terminals which can be mounted in a connector is thereby limited. This limitation on the connector length is usually a result of the fact that extremely close dimensional tolerances must be maintained in these micro-miniature connectors and the length of the connector must be limited to avoid a tolerance accumulation which might prevent mating of the connector parts with each other. Other available connecting devices which can be used or designed with 0.050 inch spacing between adjacent terminals are satisfactory in most respects except for their relatively high cost which precludes their use in mass produced electronic goods which must be sold at a moderate cost.

It is accordingly an object of the invention to provide an improved multi-contact electrical connector assembly. A further object is to provide a connector assembly having contact terminals therein on closely spaced centers and which can be produced with a relatively large number of individual contact terminals. It is a further object to provide contact terminals which can be made in an extremely small size from relatively thin metal stock without sacrifice of electrical performance or mechanical robustness.

These and other objects of the invention are achieved in preferred embodiments thereof which are briefly described in the foregoing abstract, which are described in detail below, and which are shown in the accompanying drawing in which:

FIG. 1 is a perspective view of a channel-shaped female contact terminal in accordance with the invention.

FIG. 2 is a perspective view of a male contact member in accordance with the invention.

FIG. 3 is a perspective view of a connector assembly in accordance with the invention illustrating the manner in which the conductors on a printed circuit mother board are disengageably connected to the conductors on a printed circuit daughter board.

FIG. 4 is a sectional side view of a connector assembly in accordance with the invention taken along the lines 4--4 of FIG. 3, this view showing the connector parts in engagement with each other.

FIG. 4A is a view similar to FIG. 4 but showing the parts disengaged from each other.

FIG. 5 is a sectional view taken along the lines 5--5 of FIG. 4.

FIG. 5A is a view similar to FIG. 5 but showing the two parts of the connector disengaged from each other.

FIGS. 6 and 7 are views taken along the lines 6--6 and 7--7 of FIGS. 5 and 5A respectively.

FIG. 8 is a perspective view of an alternative embodiment of the male contact member in accordance with the invention.

Referring first to FIGS. 1 and 2, a pair of electrical contact terminals in accordance with the invention comprises a male or spring contact terminal 2 and a female socket contact generally indicated at 4. The spring contact member 2 comprises front and rear U-shaped sections 6, 8 which are connected to each other by semi-elliptic springs 16, 18. The front U-shaped section has a web 12, sidewalls 10, and inwardly directed flanges 14 extending towards each other from the forward ends of the sidewalls to provide a stop means as will be described below. The semi-elliptic spring 16 is integral with the web 12 of the front U-shaped section and the web 20 of the rear U-shaped section, the remaining springs 18 being integral with, and extend between, the sidewalls 10 of the front section and the sidewalls 22 of the rear section. The three springs are outwardly bowed to the same degree and extend beyond the planes defined by the webs and sidewalls of the two channel sections.

A generally channel-shaped mounting section 23 extends from the rear channel section 8 of the contact portion and is connected to the sidewalls 22 by inwardly directed transition sidewalls 25. This mounting section comprises a web 24 and sidewalls 26 and is substantially wider than the front or forward channel sections 8, 6. A lance 28 is struck from the web 24 and is directed obliquely forwardly with respect to the axis of the terminal. An embossment 30 may be provided on the web to assist in stabilizing the terminal in a housing cavity as will be described below. A post 32 which has an L-shaped cross section extends from one of the sidewalls 26 and is electrically connected as by soldering to external conductors as will also be described below.

The socket contact 4 in accordance with the invention is in the form of a simple channel comprising a web 34 and sidewalls 36, the dimensions of this channel being uniform throughout its length. A forwardly directed lance 38 is struck from the web adjacent to the rearward end thereof and forwardly of this lance, inwardly directed flanges 40 are provided on the sidewalls 36. The forward ends of the sidewalls 36 are rounded and swaged as indicated at 42 and the forward end of the web 34 is swaged on its underside as shown at 44 to facilitate engagement of the terminal 4 with the terminal 2. As best shown in FIGS. 4A and 5A, the rounded ends of the sidewalls 36 extend beyond the end 44 of the web, a condition which further facilitates engagement of the terminals with each other.

Contact terminals as shown in FIGS. 1 and 2 are intended to be mounted in connector housings of the type shown at 46 and 48 in FIGS. 3, 4, 4A, 5, and 5A. Each of these housings has a plurality of cavities extending therethrough which receive a terminal so that when the two housing parts are engaged with each other, the individual terminals will be engaged. The housing 46 in which the spring contacts 2 are mounted has cavities 52 extending from its mating face or upper face 54, to its rearward side or face 56. Each cavity has a generally rectangular cross section defined by a top wall 62, sidewalls 64, and a bottom wall 66. A rib 68 extends from the bottom wall 66 intermediate the ends of the cavity and defines forwardly and rearwardly facing shoulders 70, 72. The entrance to each cavity is flared or beveled as shown at 58, 60 to guide the mating channel contacts into the cavities when the connector parts are engaged with each other. As best shown in FIGS. 4 and 5, the cavities are dimensioned such that the semi-elliptic springs 16 are disposed against the top walls 62 so that the terminal is urged against the bottom wall 66. The rib 68 of each cavity has a width which is only slightly smaller than the spacing between the sidewalls of the front and rear channel portions of the contact section of the terminal so that the terminal is centered in the cavity as viewed in FIG. 4A. The semi-elliptic springs 18 will ordinarily be spaced from the sidewalls 64 as is apparent from FIG. 4A and the length of the rib 68, and the fact that it extends between the sidewalls of both of the U-shaped or channel sections 6, 8, prevents any substantial lateral movement of the terminal. It should also be noted that the terminal is recessed from the mating side 54 of the housing so that the channel contacts in housing 48 will be substantially aligned with the spring contacts by the cavity sidewalls in housing 46 before there is any physical engagement between the terminals of the two parts.

As shown in FIG. 4A, the post portions 32 of the spring contacts extend through openings in the printed circuit mother board 50 and are soldered to the conductors on the underside of this board.

Each cavity 76 in the housing 48 extends from the mating face 91 of this housing to the rearward or upper face 92 and receives one of the channel-shaped contacts 4. The cavities are accordingly of rectangular cross section having dimensions conforming to the width and height of the terminals. Beveled entrance portions 86, 88 are provided for each cavity to permit limited lateral movement or "float" of the terminal so that the channel contacts will be permitted to align themselves with the spring contacts when the parts of the connector assembly are mated. Each channel contact is oriented in its cavity such that the web portion 34 of the contact is against the cavity top wall 78 and the sidewalls 36 of the channel are against the cavity sidewalls 80. A relatively short rib 84 extends centrally from the bottom wall 82 of each cavity and is located between the forward end of lance 38 and the inwardly turned flanges 40. This rib thus prevents axial movement of the contact after insertion. The post portions 42 of the channel-shaped contacts extend upwardly as viewed in FIG. 4 and are soldered to the conductors 96 on the printed circuit daughter board 94.

The contacts, both the channel contacts and the spring contacts, are assembled to the housings 46, 48 by insertion into the cavities from the mating sides of the housings. The lances of the contacts are deflected during such insertion until they pass the ribs 68, 84 at which time they return to their normal positions and the contacts are locked in the cavities.

As shown in FIG. 3, the housing 48 has downwardly extending ears 98 at each end which interfit with recesses 100 on the housing part 46. The printed circuit daughter board is recessed in a central axially extending groove 90 on the rearward side 92 of the housing part 48, ears 102 being provided on the ends of this housing part and suitable fasteners as indicated being mounted in these ears to secure the daughter board to the housing.

As noted above, connecting devices in accordance with the invention can be produced in extremely small sizes, without sacrifice of the electrical or mechanical requirements of a serviceable and practical connector. Such close spacing is permitted by virtue of several features of both the spring and channel contacts. For example, the exposed terminal is in the channel contact rather than the spring contact and a channel shape is a structurally durable and strong design. Contact terminals in accordance with the invention must be manufactured from extremely thin stock, for example, 0.004 inch in thickness and while this is extremely thin metal strip, a channel shape formed from such stock possesses the durability and strength needed in an exposed electrical contact terminal. The spring contact, which is more subject to damage, is entirely recessed within a cavity and is thereby protected.

It will be apparent from FIGS. 5 and 5A that very little lateral movement of the contacts is permitted in the horizontal directions as viewed in this Figure. In fact, it is in this plane that extremely close spacing is required and the thickness of the walls between adjacent cavities is therefore very limited. The terminals shown do not require any substantial float in the horizontal direction as viewed in FIG. 5 by reason of the fact that each of the spring contacts is biased against the bottom wall 66 of its cavity and when the channel contact enters the cavity, the spring 16 is flexed as the swaged end 44 of the web of the channel moves past the spring. Furthermore, the springs 18 may be spaced from the sidewalls 64 and the sidewalls of the channel contact are thereby permitted to move past these springs when the parts are engaged.

Substantial float of the contacts in the horizontal direction as viewed in FIG. 4 is permitted so that the channel contacts can align themselves with the spring contacts when the two connector parts are mated. It should be noted that the spacing between adjacent contacts as viewed in FIG. 4 can be somewhat greater than the spacing between adjacent contacts in FIG. 5. This difference results from the fact that the thickness of the printed circuit daughter board defines the minimum spacing in FIG. 4 while the spacing between conductors on the printed circuit daughter board defines the spacing between contacts in the other direction (FIG. 5).

FIG. 8 shows an alternative embodiment of a spring contact in accordance with the invention which is similar to the embodiment of FIG. 2 excepting that the spring 16 has been severed from the web portion 20 of the rearward U-shaped or channel section of the contact portion, although the springs 18 are integral with the sidewalls of both U-shaped contact portions. This embodiment may prove desirable over some circumstances in that its use would permit a reduction of the insertion force required to mate the connector part 48 with the connector part 46. As will be apparent from FIGS. 4 and 5, the spring 16 will be flexed to a greater extent than the springs 18 when the channel contact is engaged with the spring contact because of the fact that the spring 16 is normally against the cavity wall 62 while the springs 18 are not supported by a cavity wall. This unequal stressing of the springs 16 as compared with the springs 18 may, under some circumstances, result in the development of torsional stresses in the forward channel section 10 of the contact with resulting misalignment and an increase in the force required to engage the contacts with each other. To eliminate such torsional stressing and to equalize the behavior of the springs, the spring 16 can be severed at its rearward end from the web 20 so that it is free to move over the web portion 20 as it is flexed by the channel contact. The desirability of using this embodiment will depend on several factors such as the contact force which is desired, the material from which the terminals are manufactured, and the hardness of these materials.

Claims

WE CLAIM:

1. A disengageable electrical connection comprising,

first and second insulating housings, said housings having mating faces in abutting relationship,

first and second contact cavities extending through said first and second housings respectively, said cavities having rectangular transverse cross-sections,

first and second contact terminals in said first and second cavities, said first contact terminal comprising an elongated channel-shaped member having a leading end portion extending beyond said mating face of said first housing and into said second contact cavity in said second housing,

said second contact terminal having a resilient contact portion adjacent to said mating face, said resilient contact portion comprising a pair of spaced apart channel sections and three leaf springs connecting the sidewalls and webs of said channel sections, said leaf springs being normally outwardly bowed relative to the planes defined by said webs and sidewalls of said channel sections,

said leading end portion of said first contact terminal being in surrounding relationship with said contact portion of said second contact terminal with said channel sections of said second contact terminal in the same orientation as said projecting channel portion of said first terminal, said springs being inwardly flexed, relative to the axis of said second terminal and bearing against internal surface portions of said first terminal.

2. An electrical contact terminal having resilient contact means extending from a location intermediate the ends thereof to one end of said terminal, said resilient contact means comprising:

first and second channel sections each comprising a web and sidewalls, said channel sections being spaced apart and aligned with each other,

first, second, and third leaf spring means, said first leaf spring means being integral at its ends with the opposed edges of said webs of said channel sections, said second and third spring means being integral with opposed edges of said sidewalls of said channel sections,

said first, second and third leaf spring means being outwardly bowed relative to the planes defined by said webs and sidewalls, said terminal being engageable with a complementary channel shaped terminal having opposed sidewalls.

3. A multi-contact electrical connector of the type comprising an insulating block having a plurality of contact receiving cavities extending therethrough from the rearward face thereof to the mating face and having electrical contact terminals in each of said cavities,

said cavities having a rectangular cross-section,

each of said contact terminals having a contact portion at its forward end proximate to said mating face, each said contact portion comprising forward and rearward U-shaped sections and three semi-elliptic spring members extending between said U-shaped sections, the center one of semi-elliptic spring members being substantially against one wall of said cavity thereby to locate said contact terminal against the wall of said cavity which is opposite to said one wall,

rib means integral with, and extending centrally from, said opposite wall of said cavity and into said contact terminal, said rib means functioning to center said contact terminal between the two remaining walls of said cavity, said semi-elliptic spring members which are proximate to said remaining walls being spaced from said remaining walls,

a channel section extending from said rearward U-shaped section, said channel section having a web disposed proximate to said one cavity wall and having sidewalls disposed proximate to said remaining cavity walls,

lance means struck from said web and having a free end in engagement with the rearward end of said rib means thereby to retain said terminal against forward movement in said cavity, and

stop means extending from said forward U-shaped section, said stop means being engageable with the forward end of said rib means thereby to retain said terminal against rearward movement in said cavity,

each of said terminals being engageable with a channel-shaped terminal extending from a complementary multi-contact connector oriented such that the web of said channel-shaped contact terminal moves between said center spring and said one wall of said cavity and said remaining springs are received between the sidewalls of said channel shaped terminal.

4. A stamped and formed electrical contact terminal which is adapted to be mounted in a cavity in an insulating housing, said terminal comprising:

a contact portion having first and second U-shaped sections, said sections being in axial alignment and spaced from each other.

contact springs extending between the corresponding sidewalls of, and the webs of, said U-shaped sections, said contact springs being outwardly bowed relative to the axis of said terminal, said springs being integral with the web and sidewalls of one of said U-shaped sections and being integral with at least the sidewalls of the other one of said U-shaped sections,

a mounting section integral with, and extending from said second U-shaped contact section, said mounting section having a channel-shaped cross section comprising a web and sidewalls, the width of said mounting section being greater than the width of said U-shaped sections of said contact portions, and

stop means comprising inwardly directed ears extending towards each other from said sidewalls of said first U-shaped section and a lance struck from said web of said channel-shaped mounting section, said lance being directed obliquely inwardly and towards said contact portion whereby,

said terminal can be mounted in a rectangular cavity having centrally located forwardly and rearwardly facing shoulders, said ears being cooperable with said forwardly facing shoulder and said lance being cooperable with said rearwardly facing shoulder to retain said terminal in said cavity, said terminal being engageable with a channel-shaped complementary terminal upon insertion thereof into said cavity.