FLAT CIRCUIT CONNECTOR WITH PIVOTED ACTUATOR
Field of the Invention: This invention generally relates to the art of electrical connectors and, particularly, to a connector for terminating a flat circuit, such as a flat flexible circuit, a flexible printed circuit or other flat electrical cable.
Background of the Invention: A wide variety of electrical connectors have been designed for terminating flat cables or circuits. A typical connector for flat circuits includes a dielectric housing molded of plastic material, for instance. The housing has an elongated opening or slot for receiving an end of the flat circuit which has generally parallel, laterally spaced conductors exposed across the end. A plurality of terminals are mounted in the housing and are spaced laterally along the slot, with contact portions of the terminals engageable with the laterally spaced conductors of the flat circuit. An actuator often is movably mounted on the housing for movement between a first position whereat the flat circuit is freely insertable into the slot and a second position whereat the actuator clamps the circuit in the housing and biases the circuit against the contact portions of the terminals. FIGS. 16 and 17 herein show a prior art flat circuit connector of the character described above. The connector includes a housing, generally designated 20, having a plurality of terminals, generally designated 22, mounted in the housing from the rear thereof. The housing is mounted on a printed circuit board (not shown) and is fabricated of dielectric plastic material. The housing has a slot 20a at the front thereof for receiving an end of a flat circuit in a circuit insertion direction as indicated by arrow "B". The housing includes a rear portion 24b having a plurality of pairs of terminal-receiving passages 20c into which terminals 22 are mounted. Finally, the housing is elongated and includes a pair of walls or fixing arms 20d having fixing grooves 20e formed on the insides thereof. An elongated actuator, generally designated 24, is pivotally mounted on housing 20 by means of a pair of fixing protrusions 24a having pivot bosses 24b at opposite ends of the housing. The fixing protrusions are rotatably mounted in
fixing grooves 20e formed inside arms 20d. A pair of locking protrusions 24c are formed at opposite ends of the elongated actuator at the front thereof. The locking protrusions are hooked against the front of the housing when the actuator is in a closed position as shown in FIG. 16. A pair of substantially enclosed fitting nails are mounted over generally inverted T- shaped mounting portions 20f of the housing in the direction of arrows "B". The fitting nails are fabricated of metal material and are soldered to mounting pads on the printed circuit board to secure the connector to the board. Actuator 24 is rotated 90° from its closed position shown in FIGS. 16 and 17, to stand upright, and its rear end is inserted between fixing arms 20d of the housing. Fixing protrusions 24a are respectfully inserted into fixing grooves 20e inside arms 20d to fixed the actuator to the housing. This defines the open position of the actuator. While the actuator is in this open position, the end of the flat circuit is inserted into slot 20a in the direction of arrow "A". The actuator then is rotated about pivot bosses 24b to the closed position shown in FIGS. 16 and 17 to bias appropriate contacts on the bottom of the flat circuit against terminals 22. The prior art connector described above has problems in that the actuator is not solidly locked in its closed position. Locking protrusions 24b are locked by a weak friction force and is apt to be released upon impacts or even slight upward forces. The pivot connections between the actuator and the housing also are weak because there is no means to hold the respective pivoting portions in engagement. The present invention is directed to solving these various problems.
Summary of the Invention: An object, therefore, of the invention is to provide a new and improved electrical connector for connecting a flat electrical circuit to a printed circuit board. In the exemplary embodiment of the invention, the connector includes a dielectric housing having a slot at a front portion thereof for receiving an end of the flat circuit in a circuit insertion direction. A plurality of terminals are mounted on the housing in a side-by-side array and spaced along the slot. An actuator is movably mounted on the housing for movement between an open position allowing the flat circuit to be inserted into the slot and a closed position biasing the flat circuit against the terminals. At least some of the terminals comprise pivot terminals having pivot means for engaging a pivot portion of the actuator to provide for pivotal movement of the actuator between its open and closed positions. At least one fitting nail
is mounted on the housing for fixing the housing to the printed circuit board. The fitting nail has biasing means for biasing the pivot portion of the actuator into engagement with the pivot means of the pivot terminals. According to one aspect of the invention, the fitting nail is stamped and formed of sheet metal material. The fitting nail includes a mounting portion for mounting the fitting nail on the housing, a fixing portion for fixing the connector to the printed circuit board, and a biasing portion for engaging the actuator and biasing the pivot portion thereof generally transversely of said circuit insertion direction into engagement with the pivot means of the pivot terminals. According to another aspect of the invention, the pivot terminals include pivot arms with said pivot means thereon, contact arms extending into the slot for engaging appropriate contacts on the flat circuit, and feet portions for connection to appropriate circuit traces on the printed circuit board. As disclosed herein, the pivot means comprise downwardly opening pivot grooves in the pivot arms. The pivot portion of the actuator comprises a pivot shaft, and the biasing means on the fitting nail comprises an elevating cam for engaging the actuator and elevating the pivot shaft into the pivot grooves. According to a further aspect of the invention, the housing and the slot therein, as well as the actuator, are elongated. A pair of the fitting nails are mounted at opposite ends of the elongated housing adjacent opposite ends of the elongated actuator. The actuator has a pair of rotating cams at opposite ends thereof engageable in the rotating grooves in a pair of end walls at opposite ends of the elongated housing. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.
Brief Description of the Drawings: The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: FIG. 1 is a perspective view of a flat circuit connector according to the invention, with the actuator in its closed position;
FIG. 2 is an exploded perspective view of the connector; FIG. 3 is an enlarged front-to-rear section through the connector, with the actuator in its open position; FIG. 4 is a view similar to that of FIG. 3, with the actuator in its closed position; FIGS. 5A-5D are fragmented perspective views, partially in section, of one end of the connector, showing sequential movement of the actuator from its open to its closed positions; FIGS. 6-13 are views similar to that of FIGS. 3 and 4, but showing the sequential steps of assembling the actuator, the terminals and the fitting nails to the housing of the connector; FIG. 14 is a view similar to FIG. 3, but showing a flat circuit about to be inserted into the connector; FIG. 15 is a view similar to that of FIG. 4, with the flat circuit fully inserted and terminated in the connector; and FIGS. 16 and 17 are views of the prior art connector described in the Background, above.
Detailed Description of the Preferred Embodiment: Referring to the drawings in greater detail, and first to FIGS. 1 and 2, the invention is embodied in an electrical connector, generally designated 30, for connecting a flat electrical circuit 32 (Figs. 14 and 15) to a printed circuit board (not shown). The flat electrical circuit may include flat cables or circuits, flat flexible cables, flexible printed circuits or the like. Connector 10 includes a dielectric housing, generally designated 34, which is elongated and may be molded of plastic material. The housing defines a slot, generally designated 36, at the front end of the housing for receiving an end of the flat circuit in a circuit insertion direction as indicated by arrow DCD in FIG. 2. A plurality of conductive terminals, generally designated 38, are mounted in housing 34 in a side-by-side array and spaced along slot 36. Only the two end-most terminals are shown in FIG. 2. An actuator, generally designated 40, is pivotally mounted on housing 34 for movement between an open position (Fig. 3) allowing the flat circuit to be inserted into slot 36 and a closed position (Fig. 4) biasing the flat circuit against the terminals, as will be seen hereinafter. The terminals are inserted into the rear of the housing in the direction of arrows "D" and a pair of fitting nails, generally designated 42, are inserted into the front of the housing in the direction of arrows "E".
Referring to FIGS. 3 and 4 in conjunction with FIG. 2, terminals 38 are inserted into terminal-receiving passages 43 in housing 34. Each terminal includes a generally horizontally oriented, U-shaped configuration defined by a base, 38a, an upper pivot arm 38b and a lower contact arm 38c. The upper pivot arm has a pivot groove 38d formed in the underside thereof near the distal end thereof. The contact arm has a contact portion 38e at the distal end thereof projecting into the circuit-receiving slot 36. A foot 38f projects downwardly from base 38a and is disposed generally flush with the bottom of housing 34 for connection to an appropriate circuit trace on the printed circuit board. The terminals are stamped and formed of conductive sheet metal material. Housing 34 is elongated and includes an upstanding rear portion 34a and a bottom, forwardly projecting platform portion 34b whereby the circuit-receiving slot 36 is open in an upward and forward direction. A plurality of generally parallel guide grooves 44 are spaced along platform portion 34b between a plurality of partitions 44a. When terminals 38 are inserted into the housing, contact arms 38c are guided into grooves 44, with the contact portions 38e projecting upwardly into the circuit-receiving slot 36. A pair of end walls 34c are formed integrally with housing 34. Fitting nails 42 are inserted in the direction of arrows "E" into a pair of inverted L-shaped nail-receiving passages 46 formed in the pair of end walls and opening at the front of the housing. An upwardly opening actuator-receiving slot 48 is formed in each end wall 34c at the rear thereof behind and in communication with the respective nail-receiving passage 46. A rotating cam groove or recess 50 is formed inside each end wall 34c within slot 48. The cam-receiving groove 50 includes a first cam groove or recess 50a and a second cam groove or recess 50b above the first groove, for purposes described hereinafter. A locking groove 52 is formed on the inside of each end wall 34c above the respective nail-receiving passage 46. Actuator 40 is elongated and includes an elongated pressure plate 40a along the front thereof and an elongated pivot shaft 40b along the rear thereof spaced from the pressure plate. The actuator is a one-piece structure, and pivot shaft 40b is connected to pressure plate 40a by a plurality of supports 54 at spaced intervals along the length of the actuator, and defining spaces 56 between the supports. A rounded pressing portion 40c is formed at the bottom rear corner of the actuator.
Actuator 40 further includes a block-like support boss 58 at each opposite end thereof. A rotating cam 60 projects outwardly from the outer surface of boss 58. Boss 58 has a support 58a and a movement prevention portion 58b, for purposes described hereinafter. Pressure plate 40a of actuator 40 includes a cut-out 62 at each corner thereof. Finally, a locking protrusion 64 projects outwardly from each opposite end of pressure plate 40a. Each fitting nail 42 includes an L-shaped mounting portion 42a defined by a vertical or upright support plate 42b and a horizontal support plate 42c. The L-shaped mounting portion is insertable into the respective L-shaped passage 46 at the front of the respective end wall 34c of the housing. The fitting nail has a horizontal fixing plate or foot 42d at the bottom thereof and which will be generally flush with housing 34 for connection, as by soldering, to a mounting pad on the printed circuit board to fix the connector to the board. An open-sided hole 42e is formed in the outer edge of fixing plate 42d for receiving a fixing member (not shown) to further fix the connector to the board. According to the invention, each fitting nail 42 includes a biasing portion or elevating arm 42f in the form of a vertical plate for biasing actuator 40 upwardly and securely seat pivot shaft 40b of the actuator into pivot grooves 38d of terminals 38. In essence, plate 42f vertically supports the actuator, particularly in its closed position. FIG. 3 shows actuator 40 in an upright or open position so that an end of a flat circuit can be inserted freely into slot 36 in the direction of arrow DCD. It can be seen that pivot shaft 40b is seated in pivot grooves 38d in the underside of pivot arms 38b of terminals 38. After the flat circuit is inserted into space 36, actuator 40 is pivoted downwardly in the direction of arrow DFD to its closed position shown in FIG. 4. In this position, pressure plate 40a of the actuator will press the flat circuit against contact portions 38e of contact arms 38c of the terminals. FIGS. 5A-5D also show sequential depictions of actuator 40 being pivoted from its open position (Figs. 5A and 5B) in the direction of arrow "F" (Fig. 5C) to its closed position (Fig. 5D). It can be seen that support boss 58 of the actuator is positioned within the actuator- receiving slot 48 in end wall 34c of the housing. Cam projection 60 is located in cam groove 50b. When the actuator is rotated to its closed position, locking projection 64 snaps into locking groove 52 (see Fig. 2) in the inside of end wall 34c. FIGS. 6-15 show the assembly and operation of flat circuit connector 30. As seen in FIGS. 6 and 7, actuator 40 is assembled to housing 34 by orienting the actuator in an upright position and moving the actuator downwardly in the direction of arrow "G". During assembly,
cam projections 60 snap into cam grooves 50a in the inside surfaces of end walls 34c. To that end, the outer surfaces of cam projections 60 are tapered, and the longitudinal distance between the outer extremities of cam projections 60 is slightly larger than the distance between the inside surfaces of end walls 34c so that the end walls spread outwardly due to their own elasticity, and the end walls move back inwardly to their normal condition once cam projections 60 "snap" into first cam grooves 50a. Referring to FIGS. 8-10, terminals 38 are assembled into passages 43 in housing 34 by first pivoting actuator 40 to its closed position as shown in FIG. 8. The terminals are inserted into the passages in the direction of arrow "D" until the terminals are firmly seated as shown in FIG. 10. It can be seen that pivot shaft 40b of actuator 40 is not seated in pivot grooves 38d of the terminals, because cam projections 60 are in first cam grooves 50a as described above in relation to FIG. 2. Pivot arms 38b of the terminals are located in spaces 56 between supports 54 of the actuator. Contact arms 38c of the terminals extend into guide grooves 44 between partitions 44a on top of platform portion 34b of housing 34. FIGS. 11-13 show the affect of fitting nails 42 being inserted in the direction of arrow
"E" (Fig. 11) into the nail-receiving passages 46 (Fig. 2) of housing 34. When the fitting nails are fully inserted into the housing, biasing portions or plates 42f of the fitting nails form elevating cams which engage the bottom of actuator 40, as at 70 (Fig. 3), to bias the actuator upwardly. The effect of this upwardly biasing motion of the actuator moves pivot shaft 40b of the actuator into pivot grooves 38d of terminals 38 to rigidly secure the actuator in the connector and to allow for positive pivoting of the actuator relative to the housing. In addition, cam projections 60 (Fig. 2) will move from first cam grooves 50a to second cam grooves 50b. FIG. 14 shows the entire connector 30 in assembled condition and actuator 40 pivoted upwardly to its open position to allow flat circuit 32 to be inserted into slot 36 in the direction of arrow "C". It can be seen that pivot shaft 40b of the actuator is securely seated within cam grooves 38d of terminals 38 because of the fitting nails. FIG. 15 shows actuator 40 having been pivoted downwardly to its closed position whereat pressure plate 40a biases flat circuit 32 into engagement with contact portions 38e of . contact arms 38c of terminals 38. In addition, it can be seen how pressing portion 40c at the bottom of the actuator presses onto the top of the flat circuit and actually deforms the flat circuit into engagement with the top edge of contact arm 38c of the terminal. This deformation is
effective along the entire length of the actuator to prevent the flat circuit from being pulled out of the connector. In the closed position of actuator 40, locking protrusions 64 (Fig. 2) snap into secure locking positions within locking grooves 52 of the housing. Referring specifically to FIG. 15, it can be understood that pivot shaft 40b defines a pivot point about which actuator 40 is rotated. It can be seen that pressure plate 40a is in front of a vertical plane passing through the pivot point or shaft, and pressing portion 40c is rearwardly of the pivot point. Therefore, the pressing portion performs a dual function of (1) pressing the flat circuit against the terminals, and (2) providing an over-center means to resist rotation of the actuator away from its closed position. It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.