GB2262847A

GB2262847A - Flat flexible cable connector with cable retaining keyway

Info

Publication number: GB2262847A
Application number: GB9226297A
Authority: GB
Inventors: Akira Imai
Original assignee: Whitaker LLC
Current assignee: Whitaker LLC
Priority date: 1991-12-27
Filing date: 1992-12-17
Publication date: 1993-06-30
Also published as: JP3088169B2; JPH05182723A; GB9226297D0

Abstract

An electrical connection includes a connector (10) and a flat flexible cable (50). The connector has a housing (20) including an array of cavities (23) intersected by a slot (22) of a length and width to receive the cable (50) inserted therein. The conductors (52) of the cable are disposed in spaced array on an insulating sheet (51) and contacts (30) in the housing cavities (23) engage and terminate the conductors with posts (36) of the contacts being adapted to connect to other circuits. The cable includes a keyway relief formed in the insulating sheet of the cable and the connector includes at least one key (40) positioned in a contact cavity (23) to fit into the cable relief and with the key having means (44) to engage a surface in the keyway to latch the cable to the keyway and thus to the connector housing. <IMAGE>

Description

FLAT FLEXIBLE CABLE CONNECTOR WITH CABLE RETAINING KEYWAY This invention relates to an electrical connector for flat flexible cable having a polarizing and retaining key.

Flat flexible cable (FFC) is widely used to connect circuitry between printed circuit boards and electronic devices or equipment. FFC is a relatively flat cable made by arranging a number of flat conductors, parallel to each other, on an insulating sheet or film. Each end of the cable is connected to the conductive pads of circuit boards or to other connectors that go to electronic devices. Connectors of various designs have been developed to terminate FFC cable, including of a type disclosed in Utility Model 3 - 22869, Utility Model Hei 3967, and Japanese Patent 59 - 23482. In Japanese Utility Model 3 - 26988, a technique is taught to reduce the force required to insert the FFC into a connector and in another type of connector, 2 - 35428, the contacts are staggered to reduce the force required to terminate the cable to the connector.With respect to the foregoing patents, and to the present application, a constant need is one of being able to manufacture FFC and make sure that a given harness made of such cable fits within an appropriate connector.

Another requirement is that the cable be retained in some manner relative to the connector. At the same time, the solution to these problems needs to be inexpensive and simple and to allow cable and connectors to be on relatively small centers as is required by the increasing use of harnesses made of FFC in small, portable electronic equipment.

Accordingly, it is an object of the present invention to provide a FFC connector having cable retention and polarizing features of an improved nature. It is a further object to provide a simple and inexpensive FFC connector that allows the cable and connector to be matched together by physical features in the connector and cable. It is yet a further object to provide a high density electrical connection for FFC that facilitates orientation and cable retention to the connector.

The present invention achieves the foregoing objectives through the combination of a connector housing having a row of terminal cavities extending therethrough from a forward face to a rear face with a slot transsecting such cavities in the rear face of the connector housing. Contacts are shaped to fit within such cavities and be held therewithin to engage the conductors of an FFC and be terminated thereto by the simple insertion of the cable into the slot of the housing and in engagement with the -contacts. Such contacts have, on the cable receiving end, a resilient finger that includes a contact point driven to bite into the cable conductor, and on the other end, one or more posts that can be inserted in a printed circuit board and soldered thereto, or can be plugged into a further connector.The cable is made in a preferred embodiment of a thin plastic sheet, typically a film such as polyester having conductors bonded thereto in a spaced array matching the center-to-center spacing of contacts in the connector. In between cable conductors, a portion of the insulating material of the cable is removed and given a particular configuration, either in the form of a slit with an offset surface or a slot or aperture. A key is provided of a configuration to fit within a contact cavity in an appropriate position in the housing of the connector so as to receive the cable with the removed portion fitting into the key in a manner to be retained by the key and thus be retained relative to the connector housing.In this way, the FFC is oriented or polarized relative to the connector, depending upon the positioning of the key in a given cavity in the connector housing and the particular location of the removal of material of the cable. The contacts and key of the invention are preferably made of flat plastic stock to be essentially plantar so as to be placed on close centers in a connector. In one nbmiiemt, the key is ooçde- tely planar with the retaining structure residing in the plane of the key, and in another emmeet, a finger is oriented obliquely fran the plane of the key to engage the cable at a surface formed by removal of material.

In the accompanying dahings:- Figure 1 is a plan view of the rear face of the connector of the invention with contacts and key shown mounted in the housing thereof, Figure 2 is a sidle, partially sectioned view taken through lines 2-2 of Figure 1, Figure 3 is a side, partially sectioned view taken through lines 3-3 of Figure 1, Figure 4 is a perspective showing the end of a cable and the connector key positioned apart, Figure 5 is a plan view showing the cable engaged by tble embodiment of the key of the invention shown in Figure 4, and Figures 6 and 7 are perspective views showing an alternative embodiment of cable end and connector key in accordance with the invention.

Referring now to Figures 1-3, a connector 10 is shown to include a dielectric plastic housing 20 having a front rear or entry face 21 with a slot 22 extending along the length of the housing. Extending transversely to the slot and down through the housing are a series of cavities 23 that have a configuration as shown in Figures 1 and 2, noting the through portion of the cavity 23a and a closed off portion 23b. In the front face are a series of reliefs shown as 25 in Figures 1-3 that extend part way through the housing 20. As can be seen in Figure 2, most of the cavities 23 are made to contain contacts 30 that are comprised of a flat, metal stamping of spring grade material to include a base 31, a projection 32 that fits within the cavity 23b and holds the contact in place within the housing 20.Extending from base 31 is a post portion 36 that is utilized to terminate the connector to a printed circuit board or the like by being soldered to conductive traces on such board. It is to be understood that configurations other than post 36 are contemplated, including configurations intended for surface mounting of the connector. Between the front or insertion face 21 and a bottom surface 26, the contact 30 includes a spring arm 33 that leads to a beveled portion 34 and a contact point 35 held in a position to engage the conductive portion 52 of the cable 50. As can be seen in Figure 4, the cable 50 includes a plastic sheet material 51, typically a film with conductors 52 bonded thereon in an ordered array extending across the width of the cable.When cable 50 is inserted into connector 20, the contact point 35 rides up over the conductor and bites into such conductor, the beveled portion 34 guiding the cable into the relationship with contact 30, point 35, with a minimum of insertion force.

In accordance with the keying feature of the invention and as shown in Figures 1 and 3, a key shown as 40, typically made of a plastic material, or stamped and formed of thin metal stock, is given a configuration to fit within a contact cavity and be held therein in the manner shown in Figure 3 oriented between the insertion face 21 and the bottom face 26. As can be seen in Figures 3 and 4, key 40 includes a base portion 41, a portion 42 that fits within the cavity portion 23b and locks the key in position, an upstanding portion 43 with a finger 44 made to extend out of the plane of the key. The cable 50, as can be seen in Figures 3 and 4, is made to include a relief 53 that, in the embodiment of Figure 4, includes a slot portion 53a and an enlarged portion 53b with a tapered portion forming a surface 54.As can be seen in Figure 5, the key 40 fits within this relief in the cable with the finger 44 resting against surface 54 of the cable to lock the cable to the key and, as shown in Figure 3, lock the cable to the housing and therefore to the connector 10. The invention contemplates that one or more reliefs 53 may be provided in the cable with the cable being designed to accommodate such relief, and the need for more than one key determined by the width of the cable 50 for a given application. As can be appreciated, a cable end having no relief such as 53 could not be inserted into a connector containing a key 40 and thus would preclude an erroneous mating of cable to a connector in such circumstance.

Figure 6 shows an alternative version of the invention with a cable 50' having conductors 52' and an aperture or hole 53' punched through the plastic material of the cable 50'. In such application, as shown in Fig.

7, a key 40' is made to include a base 41', an upstanding portion 42' that locks the key to the housing, and a portion 43' that includes an aperture 46 and a projecting portion 45 that includes surface 45a, beveled to assist in insertion of the cable, and a surface 45b intended to latch the cable to the key and thus to the connector. The aperture 46 is intended to provide resilience and potential deformation of the key to facilitate insertion of the cable.

Claims

1. A multi-path interconnection including an electrical connector, a flat flexible cable having an insulating sheet with conductors affixed thereto in spaced array across the width thereof, said connector having a housing with an array of cavities in a row corresponding to the conductors of the cable, and each cavity having a contact therein with a portion of the contact engaging a cable conductor and a portion adapted to interconnect said contact to a further circuit, a slot extending across the housing and intersecting the cavities and adapted to receive the cable end inserted therein to position the conductors in engagement with the contacts, said cable having at least one keyway in the end thereof formed in the insulating sheet including a surface extending at an angle to the length axis of the cable, and a key fitted in at least one of said cavities and extending within the keyway of the cable and including means to latch the cable to the key and thereby to the connector.

2. The interconnection of claim 1, wherein the keyway is a slit extending along the length of the cable from the end and said surface extends toward the side of the cable with the key including a projection engaging said surface to latch the cable to the key and to the housing.

3. The interconnection of claim 1, wherein the keyway is an opening formed in the cable and the key includes a projection disposed in the plane of the key and engaging said opening.

4. The interconnection of claim 1, 2 or 3, wherein the contacts and the key(s) have common portions of exterior surfaces adapted to fit within the contact cavities.

5. The interconnection of claim 1, 2, 3 or 4, wherein the contacts and key(s) include projections adapted to lock them within the cavities.

6. The interconnection of any preceding claim, wherein the contacts are formed of a flat configuration from spring grade conductive material and the or each key is formed of a plastic material.

7. An electrical connector adapted to receive a flat flexible cable formed of an insulating sheet material with conductors in spaced array extending across the width of the cable and along the length of the cable and at least one keyway in the cable, comprising a housing including a row of cavities, a slot transsecting said cavities and of a dimension to receive an end of the cable inserted therein with the cable conductors being engageable by contacts in the cavities to provide a low resistance, stable electrical interconnection, and at least one key fitted in a cavity and retained therein by surface engagement, said key including a portion for engaging the keyway in the cable to latch the cable to the housing.

8. A connector of claim 7, wherein the keyway includes slot means for accommodating the key.

9. The connector of claim 7, wherein the keyway includes aperture means for accommodating the key.

10. An electrical connection or connector constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.