Electrical terminal for insulating base
US 2892177 A
Description (OCR text may contain errors)
J 2 V., w 2, 2 e z G. A. SCHERRY ELECTRIC TERMINAL FOR INSULATING BASE I Filed May 5, 1954 June 23, 1959 United States Patent 2,892,177 ELECTRICAL TERMINAL t on INSULATING BASE George A. Scherry,'Berkeley, IlL, assign'or to Grayhill, Chicago, 111., a partnership Application May 3, 1954, Serial No. 426,997 3 Claims. or. 339-2 20 This invention relates to electrical terminals and more particularly to' an elongated electrical terminal which is r Fig. 2 taken along the line 33 of Fig. 2,
supported on and extends through a base of insulating material to make electrical connection, for example, between a component on one side of the base and an interconnecting wire on the other side.
It is usual in the electronic art to mount various electrical components such as inductance coils or the like on individual bases of insulating material composed, for example, of a thermosetting resin and, when the requirement arises, also to mount an enclosing'shield for such a component on the insulating base. It has been the practice to insert small metallic terminal pins through the base to form electrical connections between the components on one side of the base, and for example, interconnecting wires on the otherside. Each such terminal pin usually has a knurled portion and is inserted in an aperture in the base ina heated condition so that the knurled portion softens the resinous material. adjacent the aperture to some extent enabling the pin to be firmly held within the aperture by the knurled portion upon cooling; Difficulties have been encountered in the use of the aforementioned terminal pins in that the insulating bases have a tendency to fracture when the pins are inserted. This condition is aggravated in units intended for ultra-high frequency applications since insulating bases suitable for such purposes are often extremely fragile and easily broken. An alternative is to mold the pins into the insulating base, but this is an expensive operation particularly when the pins are small in size. 1 It is an object of the present invention to provide an improved electrical terminal suitable for the purposes described above and which may be inserted in an insulating base and rigidly supported thereby without subjecting the base to the possibility of fracture.
A further object of the invention is to provide such an improved electrical terminalthat may beinsertedin an insulating base in an extremely simple. fashion and securely supported against. motion in such base.
A feature of the invention is the provision of an-elon'f gated tubular electrical terminal slotted to have a 0-) shaped cross section and which maybe inserted through an aperture in an insulating base,'-the terminal having "a' diameter slightly greater than the internal diameter of the aperture and composed of resilient material which may be compressed to allow the pin to be inserted in the aperture so as to-be firmly held therein when the compression is released. To prevent rotational motion, the edges of the tubular terminal adjacent the slot are shaped to project outwardly and engage the internal surface ofthe aperture, and to prevent longitudinal motion the terminal is e'quippedwith two sets of radial projections that engage respectively the two surfaces arebelieved to. benew are setiorth with particularity of the insulating base adjacent the aperture.
The above and other features of the invention which longitudinal and rotational ice" in the appended claims. The invention itself, however, together with further objects and advantages thereof may best be understood by reference to the following description when taken in conjunction with the accompanying drawing in which:
Fig. 1 shows, partly in section, an assembly incorporating the electrical terminal of this invention,
Fig. 2 represents one embodiment of the electrical terminal of the invention,
Fig. 3 showsa sectional view of the embodiment of.
Fig. 4 shows another embodiment of the invention,
Fig. 5 shows a sectional view of the embodiment of? Fig. 4 taken along the lines 5-5 of Fig. 4,
Fig. 6 is a sectional view similar to that of Fig. 5,. of yet another embodiment of the invention,
Fig. 7 is a view similar to that of Fig. 3 of a further embodiment of the invention, and
Fig. 8 is a view similar to that of Fig. 3 of a still furtheir embodiment of the invention.
The electrical terminal of this invention is intended to project through an aperture in a base of insulating materialand comprises a tubular body of resilient electrioally conductive material with a generally 'C-shaped cross section having an external diameter slightly greater than the internal diameter of the aperture. The tubular body also has a portion thereof adjacent at least one the aperture.
of its longitudinal edges with a flattened configuration to cause such an edge to project tangentially outwardly and engage the internal surface of the aforementioned aperture to prevent rotation of the tubular body in Finally, a pair of longitudinally spaced projecting means are provided on the outer surface of the body portion which are adapted to engage the re spective sides of the aforementioned insulating base adjacent the aperture and prevent longitudinal movement of the body portion within the aperture, the terminal being sufliciently resilient to allow one of the projecting means to pass through the aperture in the base during the insertion of the terminal.
The assembly of Fig. 1 comprises an insulating base 10 of a high dielectric material such as a thermosetting of base 10 may be of the order of A" x x and terminals 13 and 14 may resin upon which is mounted an inductance coil 11 and an enclosing shield 12. The two extremities of coil 11 are respectively soldered to electrical terminals 13 and 14 which are constructed in accordance with the invention and which extend through and are supported by base 10. It is to be understood that the sizes of the various components have been greatly exaggerated for purposes of clarity. For example, the actual dimensions,
be about one'inch long and .044 inches in diameter.
Terminals 13 and 14 may be constructed, for exam ple, in the manner shown in Figs. 2 and 3 and each may comprise a hollow generally tubular shaped body 15 of a resilient electrically conductive material. The tu entire length so that the body has an essentially O-shaped, cross section (as shown in Fig. 3). to enable the body. to be compressed for insertion into the aperture in the insulating base to be firmly held therein when released. Moreover, body 15 has portions 16 and 17' adjacentthe edges of the longitudinal slot of a .flattened configuration to cause such edges to project tangentially outwardly and bite intothe internal surfaceof the aforeprevent rotation of the body Body 15 has a series ofprojections 18 and a further-.Iseriesof projections 19 on its 'outer'su'r-" mentioned aperture and in the aperture.
face longitudinally spaced one from the other, the two series being adapted to engage the respective sides of base 10 adjacent the aperture in which the body is supported to prevent longitudinal movement of the body within the aperture.
The improved terminal of this invention may be inserted in base 10 in a simple and expedient manner merely by compressing the terminal and inserting it through the aperture in the base until projections 18 and 19 engage respectively the upper and lower sides of the base, the terminal being sufliciently resilient to allow projections 19 to pass through the aperture in base 10 during the insertion process. When the compression is released, the aforementioned flattened longitudinal edges bite into the surface of the aperture and prevent rotational motion of the tubular body. In addition, the projections 18 and 19, which are illustrated in this embodiment to have tapered or rounded sides, are spaced apart a distance corresponding to the thickness of the insulating base 10 and bear against the sides of the insulating base firmly to support the terminal against longitudinal motion. When the terminal is so in place, the appropriate leads may be soldered thereto. The tubular construction of the terminals facilitates the soldering of connections thereto. Moreover, due to the resilient nature of the terminal, any tendency for the base material to soften during the soldering operation does not loosen the terminal but merely causes it to expand radially further into the bore of the aperture and retain its rigid relation with the base.
Body 15 may conveniently be shaped by a series of dies, and the projections 18 and 19 may be formed therein during such shaping operation by a simple stamping operation. The cost of constructing the terminals is therefore very small.
In Figs. 4 and 5 there is illustrated a second embodiment of the terminal or insert. In this embodiment, the projections are shown to be in the form of continuous shoulders or ribs 20 and 21 which also may be formed integrally in body portion 15 during the shaping of that body. The continuous shoulders 20 and .21 are generally equivalent to the projections 18 and 19 and may be preferable for certain applications.
As illustrated in Figs. 4 and 5, when so desired, dimples may be impressed in the external surface of tubular body 15 during its shaping operation to form corresponding internal projections 22. These internal projections are positioned to form, in effect, a screw thread for receiving a screw 23 which may be conveniently threaded into the end of the tubular portion. This construction may be used to provide a solderless connector for the interconnecting leads, and/or to form mounting means for the insulating base. The screw 23 tends to expand the tubular body 15 to render the mounting thereof still more rigid. The dimples 22 are preferably placed in the illustrated angular positions so that the resilience of the pin is best used to provide a tight fitting screw thread with a locking effect.
In each instance the apertures in base that receive the terminals may be round, or they may have an'ovallike shape with substantially straight sides and roundedends, or they may have any other desired configuration.
The embodiment of Fig. 6 is generally similar to that of Figs. 4 and 5, except that each of the shoulders or ribs 20, 21 does not extend completely around the body but is formed in a pair of sections 21a, 21b adjacent the slot in the body. This permits the terminal to be rolled into shape during its fabrication process without any tendency to fracture at the ribs that could occur when some materials are used.
To increase the rigidity with which terminals 13 and 14 are supported within insulating base 10, the base may be formed with concave grooves 30 and 31 as shown, in Fig. 7 on each side surrounding the apertures, and
the projections 18 and 19 may have sides generally P511.
pendicular to the surface of body portion 15 and be spaced longitudinally on the body a distance slightly less than the thickness of the base to engage securely the concave portions so that the terminal is rigidly held against longitudinal movement. Alternatively, this rigidity may be achieved by forming the projections with rounded or slanting sides with respect to the surface of body 15 as illustrated by the tapered projections 18a and 19b shown in Fig. 8.
While the terminal of this invention finds great utility in its illustrated application of forming a connector for an inductance coilor other electrical component, it is evident that it may be used for other purposes. For example, it may be mounted on a base to form a common connector to which a plurality of common leads can be connected on one or both sides of the base; or it may be used in any other application in which a rigid connector is required.
The invention provides, therefore, an improved electrical terminal that may be constructed in a relatively simple and economical manner, and which may be inserted quickly and conveniently in an insulating base to be securely held therein against longitudinal and rotational motion without subjecting the base to fracture during the inserting operation.
While particular embodiments of the invention have been shown and described, modifications may be made, and it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.
1. An electrical terminal to be supported in a round aperture extending through a base of insulating material for making electrical connections on both sides of said base, said terminal comprising an elongated tubular body of a resilient electrically conductive material and having a length greater than the thickness of said base so that said body is adapted to extend through the aperture and on both sides thereof, said tubular body having a generally 'C-shaped cross section with a semi-circular portion and a pair of flattened portions extending tangentially outward therefrom, said flattened portions having spaced substantially parallel longitudinal edges located outside the circular projection of said semi-circular portion, said tubular body having an external transverse dimension slightly greater than the internal diameter of the aperture so that said body is compressed by the aperture upon insertion therein and said longitudinal edges bite against the internal surface of the aperture and prevent rotary,
movement of said tubular body therein, first and second series of outward projections spaced longitudinally along the outer surface of said tubular body to engage the respective sides of the insulating base adjacent the aperture and prevent longitudinal movement of said tubular body within the aperture.
2. An electrical terminal as defined in claim 1 wherein said first and second series of outward projections each includes a pair of projecting ribs extending partially around said body adjacent respective ones of said longitudinal edges.
3. An electrical terminal to be supported in a round aperture in a base of insulating material and which comprises an elongated tubular body of resilient elecextending along the entire length of said tubular body and also extending outside the circular projection of said Cgshapedcross' section so that said edgesprovide-biting en- References Cited in the file of this patent UNITED STATES PATENTS Von Scheven Feb. 19, Draving Jan. 25, Winning Mar. 18, Beggs Apr. 1, Hansman et a1. June 10, Bergman Mar. 7, Sampson Mar. 10, Hobson Feb. 8,