US3158418A - Pin contact for printed circuit boards - Google Patents

Description

Nov. 24, 1964 T. L. RUSH 3,158,418

PIN CONTACT FORPRINTED CIRCUIT BOARDS Filed Feb. 2, 1962 i liit i Hi hi l. "i I l H l INVENTOR. THOMAS L. RUSH ATTORNEY United States Patent i 3,158,418 PIN (IONTACT FOR PRINTED ClRCUlT BOARDS Thomas E... Rush, li lanhattan illeach, Califi, assignor, by mesne assignments, to the United States oi America as represented by the Secretary of the Navy Filed Feb. 2., 1962, Ser. No. 176,847 1 Claim. (Cl. 339-1") The present invention relates to contacts for unitary assemblies of the type known in the electrical art as printed circuits. This term as used herein is intended to designate any set of planar conductors and/or components which is bonded to, or otherwise supported by, an insulating board or sheet, such conductors and/ or components being adapted to replace conventional wire conductors, resistors, capacitors, etc. in an electrical circuit. These conductors and/or components may be applied to the insulating board, for example, by spraying, printing, silk screening, photo-etching or electrode position.

A majority of the printed circuits now in use are of the modular type. Tln's permits the individual subassemblies in a complex electrical network to be readily interchanged when a difierent operating function is desired, and also renders each unit easily removable in the event that replacement or repair becomes necessary. In recognition of this fact, substantially all printed circuit boards are built around the principle of plugability. This usually required that all of the conductors leading to other sub-assemblies of the network in which any particular printed circuit board is utilized be arranged to terminate along one edge of the circuit board. There are then several possible ways by means of which the components of the circuit board in question may be electrically integrated into the remainder of the system.

One common procedure is to provide a connector assembly in the form of a rectangular plug of insulating material having a plurality of spring contacts formed therein, each such Spring contact being designed for asso ciation with a particular one of the printed circuit board conductors. When such a plug is utilized, electrical engagement between the spring contacts and the respective planar conductors of the board is frictional-in nature, and all such contacting engagements are established simultaneously when the plug is brought into operating position.

However, there are occasions where it is desirable to provide a separate individual contact for each one of the terminal conductors of the printed circuit board. In these circumstances, the alignment of such contacts and the spacing therebetween is quite critical, since each contact includes an outwardly-projecting portion, or prong, which is receivable in one of the sockets of a connector block. Hence any misalignment of even a single one of these contacts may preclude a proper insertion of the prongs as a unit into the female portion of the connector. When individual contacts of the above type are utilized, rather complex apparatus is usually required to properly mount and position the contacts on the printed circuit board. Since such a manufacturing operation is performed automatically, misaligned assemblies frequently remain undetected until an actual engagement of the unit with a socket is attempted.

The present invention is directed to a printed circuit connector in the form of an individual pin contact which may be readily associated with one of the planar conductors of a printed circuit board. The design of this 3,1 58,4 l 8 Patented Nov. 24, 1964 pin contact is such as to facilitate the assembly operation by which the unit is manufactured by almost completely eliminating any necessity for extensive tooling. Hence, a substantial reduction in the cost of manufacturing the connector is achieved.

Briefly stated, this result is achieved through the provision of a pin contact designed with a pair of extending portions, one of which is intended to pass through an aperture in the printed circuit board and to become aligned with that particular planar conductor which the contact pin in question is intended to electrically engage. The other of these extending portions is intended to be associated with one of a series of evenly spaced notches formed along that edge of the printed circuit board at which the series of planar conductors terminate. Following an insertion of the pin contact through these cut-out portions of the board, the contact is displaced laterally (parallel to the board surface) so that one portion thereof looks into the notch. This locking engagement between the pin contact and board defines the position of the contact with respect to its particular planar conductor. Also, a spatial relationship is established between adjacent contacts, since the position of each contact is necessarily dictated by the location of its particular notch, and all of the notches have been pro-formed to be equidistant from one another. Following insertion and subsequent movement of the contact in the manner set forth, further means are provided for locking each contact in its desired position by means of an insertable plug which is receivable within the cut-out portion of the printed circuit board. Insertion of such plug precludes subsequent movement of the pin contact during use and maintains the alignment of the prongs. The assembly operation by which the device of the present invention is fabricated can be performed at high speed and with a minimum number of steps. A plug-in unit incorporating contacts of the nature described is especially applicable to modular electrical equipment, and possesses complete interchangeability with respect to other sub-assemblies with which it may be associated.

One object of the present invention, therefore, is to provide an improved form of connector for printed circuits.

Another object of the invention is to provide a connector for printed circuits in the form of an individual pin contact for each printed conductor, such pin contact being receivable in, and indexed by, a notch formed along one edge of the printed circuit board.

A further object of the invention is to provide an individual pin contact for printed circuits which is inexpensive in cost and readily adapted to that particular circuit design into which it is to be incorporated.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a plan view of a printed circuit board which has been modified in accordance with the principles of the present invention;

FIG. 2 illustrates a preferred form of contact pin designed in accordance with the present concept, and sets forth the steps by which such contact pin and circuit board are assembled to form a unitary structure;

HO. 3 IS an enlarged View of a portion of the printed circuit of FIG. 1 showing in greater detail the manner in S which the contact pin is associated therewith; and

FIG. 4 is a plan view of the contact plug of FIGS. 1 thru 3.

Referring now to that embodiment of the present invention illustrated in the drawings, there is shown in P16. 1 a more or less conventional printed circuit board to which has been modified in a manner to be described. The board ill carries thereon a plurality of planar conductors 12 which serve to interconnect various components (not shown) making up a circuit the design and function of which forms no part of the present invention. These conductors 12 are disposed in spaced-apart fashion so as to be essentially parallel to one another and perpendicular to that particular edge 14 of board it) at which electrical connections are to be made to other portions of the overall system or network of which the circuit in question forms a part.

As best shown in the left-hand portion of FIG. 1, each of the conductors l2 terminates at the periphery of a circular aperture 1-5 which has been torme i in board adjacent the edge 14. These apertures lie equidistant from the edge 14 of the board, and are of a diameter which is preferably somewhat greater than the width of the planar conductors.

Associated with each aperture 36 is a notch 18 formed in the edge ll l of board lil. Each of the notches lb is so located that one of conductors 12 would terminate at such notch were it to be continued to the edge of the board. The width of each notch lb is slightly less than that of each planar conductor 12, as will be noted in the drawing.

In FIG. 2 is illustrated a preferred form of contact pin designed in accordance with the principles of this invention. Such pin is generally identified by the reference numeral 29, and is made up of a body portion 22 from which extends a cylindrical prong 2d. Extending in a direction generally opposite to that of prong 24 is an elongated side member 26, and at a point near the furthest extremity of side member 26, is formed an L-shaped extension 28. As will be seen in FlG. 2(a), the L-shaped extension 28, together with the terminal portion of the side member 26, defines a U-shaped recess fill.

The body portion 2.2 of pin 2% has extending therefrom a projection 32., which, together with the side member 26, establishes a further U-shaped recess 34. referring to FIG. 2(a), it will be seen that the two recesses 3b and 34 are aligned vertically (in the drawing) and lie essentially on an axis established by the prong It will be noted that this contact pin as shown in the drawing may be integrally formed, as by stamping, or the pin otherwise fabricated from a single piece of electrically-conductive material.

In FIG. 2(a) the Contact pin 2% is shown adjacent the printed circuit card 14 and ready for assembly therewith. FIG. 2(a) also shows the circular aperture 16 in card it), as well as the notch 18 aligned therewith. This relationship of the elements as set forth in FIG. 2(a) is accordingly that which exists prior to the operation by means of which these two members are brought together. If now the contact pin 2% is moved in a direction indicated by the arrow, the relationship of FIG. 2(1)) is established. As will be noted, the L-shaped extension 28 has entered the circular aperture 16 in card it), and, in similar fashion, the contact pin projection 32 has passed through the notch 18 and emerged on the opposite side of the circuit board. It will be appreciated that the vertical dimension of the L-shaped contact pin extension 28 is such as to enable it to pass through the circular aperture 16 in the circuit board.

After the elements have assumed their position as shown in FIG. 2(b), the contact pin 2t is again moved in a direction shown by the arrow, which latter movement is transverse to that which first occurred. Expressed differently, this last-mentioned movement is in a vertical (upward) direction as viewed in the drawings. Following this latter movement, that portion of the printed circuit board it) which is associated with the terminal portion of conductor 12 enters into the U-shaped recess 36 in pin 29, while that portion of printed circuit board 1% adjacent the notch 13 enters into the U-shaped recess 34. The elements now have the relative position shown in FF. 2(0). It will be recognized that the notch 13 indexes, or precisely determines, the position of the contact pin 24) laterally along the edge 14-, and the contact pin is prevented from any transverse displacement by its contact with the sides of this notch into which the body portion 22 of the pin is receivable. It will be further noted that when the pin it) has moved upwardly as shown in FIG. 2(a), the interior surface of the U-snapcd recess fa l forms a good electrical contact with the outer surface of the planar conductor 12 with which the pin 20 is associated. Any relative movement between these two memhers is prevented by means which will now be described.

Also shown in FIG. 2 is a metallic contact plug, identified by the reference numeral 36. This plug 36 is generally cylindrical in outline, and has a dimension corresponding to that or" the circular aperture 15 in the printed circuit board 159. The plug 35 (a face view of which is also shown in FIG. 2) has formed therein a notch 38 shaped so as to fit over the L-shaped extension 28 of contact pin In other words, contact plug 3 6 is designed to slide into the circular aperture 16 of the board it? after the 2% has been inserted therein and the ele ments have assumed their position as shown in FIG. 2(0). Movement of plug 36 is as shown by the arrow in this latter figure. W'hen plug 36 has entered the aperture 16, the extending portion 23 of pin 2 is held in place by the sides of the notch 38 formed in plug 36 to prevent movement of pin 2%) in any direction whatsoever from its assembled position. When the elements are completely brought together, as shown in FIG. 2(d), a small bead of solder is placed at the point illustrated between the pin and plug to prevent the latter from leaving the aperture 16.

FIG. 3 is an enlarged view of one of the contact pins of FIG. 1, showing the appearance of the complete assembly following the soldering operation mentioned in connection with FIG. 2(d). It is of course understood that the prongs 2d of the pins are intended to be receivable in the socket portion of an adaptor (not shown) from which electrical connections are made to other portions of the overall system.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

The combination with a printed circuit board of the type carrying thereon at least one planar conductor terminating adjacent the periphery of said board, said board being formed with a circular aperture therein at the edge of which said conductor terminates, said board also having along the periphery thereof a notch aligned with both said conductor and said circular aperture, of a contact pin formed of electrically conductive material and comprising a body portion, a cylindrical prong extending from said body portion, an elongated side member extending from the body portion of said contact pin in a direction generally opposite to the general direction in which said prong extends, an L-shaped extension formed on said elongated side member near the furthest extremity thereof, said L-shaped extension, together with the terminal portion of said side member, defining a first U-shaped recess, and a prog'ection extending from the body portion of said contact pin in the region of the said side member, said projection, together with that portion of said side member lying in the region thereof, defining a second U-shaped recess, whereby, when said contact pin is positioned adjacent said board so that the longitudinal axis of said pin as defined by the axis of said cylindrical prong is parallel to the plane of said board, a transverse movement of said contact pin will cause the L-shaped extension thereof to enter said circular aperture and the pin projection to pass through said notch, whereupon a further movement of said pin parallel to the plane of said board Will cause the terminal portion of said planar conductor to enter said first U- shaped recess in said pin to establish electrical engagement therebetween, while at the same time a portion of said circuit board adjacent said notch enters the said second U-shaped recess in said contact pin, and a generally cylindrical locking plug receivable in the circular aperture of said circuit board, said locking plug having a cut-out portion arranged to pass by the L-shaped extension on said contact pin following the relative movements between said pin and said board by means of which said electrical engagement has been established.

References Cited by the Examiner UNITED STATES PATENTS 2,724,811 11/55 Poupitch. 2,962,692 11/60 White. 3,027,538 3/62 Deakin.

JOSEPH D. SEERS, Primary Examiner.

ALBERT H. KAMPE, Examiner.

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