Bus bar for a circuit board

• US 5,166,867 A
• Filed: 03/17/1987
• Issued: 11/24/1992
• Est. Priority Date: 12/31/1985
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hayashi, Toshinari, Saito, Seiichi, Seyama, Kiyotaka, Kumagai, Chikayuki
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): SPARKS, DONALD ALAN
• Application Number:
  US07/027,062
• Time in Patent Office: 2,079 Days
• Field of Search: 174/68 B, 174/70 B, 174/71 B, 174/72 B, 174/88 B, 174/99 B, 174/129 B, 361/407
• US Class Current: 361/775
• CPC Class Codes: H01R 12/7088 Arrangements for power supply
• CPC Class Codes: H05K 1/0263 High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board H05K1/0293 takes precedence
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 2201/10272 Busbars, i.e. thick metal bars mounted on the PCB as high-current conductors metal strips H05K2201/1028
• CPC Class Codes: H05K 3/341 Surface mounted components

Abstract

A massive bus bar for supplying a determined power voltage to a circuit component mounted on a rigid circuit board having a conductor layer connecting the component to a bus bar connecting pad formed on the surface of the board. Plurality of first notches extend through a main surface of the bus bar from a common longitudinal edge, perpendicularly to the longitudinal axis of the bus bar and throughout the full longitudinal extent of the bus bar, and define a plurality of posts which are secured at their bottom surfaces to the conductive pads on the circuit board surface. The first notches facilitate flexing of the bus bar and reduce stresses otherwise produced due to the rigid connection of the bus bar to the circuit board, while not significantly diminishing the current handling capability of the bus bar. Second and third pluralities of orthogonally extending notches, respectively parallel and perpendicular to the longitudinal axis of the bus bar, are formed in the bottom surfaces of each post, further reducing stresses.

Claims

1. A bus bar comprising:

an elongated bar of metallic, conductive material defining a longitudinal axis and having a generally rectangular cross-section in a plane perpendicular to the longitudinal axis and parallel, major rectangular surfaces of common, predetermined length and height dimensions respectively parallel to and transverse to the longitudinal axis and parallel minor surfaces extending between the major surfaces and corresponding to the thickness dimension of the bar, one of said minor surfaces comprising a longitudinal mounting edge of the elongated bar; and

said longitudinal mounting edge and adjacent portions of said parallel major rectangular surfaces of said bar comprising a plurality of posts defined by a corresponding plurality of first notches extending through the full thickness of the bar, transversely from the longitudinal mounting edge thereof to no greater than one-third the height dimension of the bar, said posts and first notches having respective, relative width dimensions in a direction parallel to the longitudinal axis of no greater than 10 to 1, and

a plurality of second notches in the mounting edge surfaces of said posts, extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts.

3. A bus bar as recited in claim 1, wherein said plurality of said first notches extend to one-third the height dimension of the bar.

4. A bus bar as recited in claim 3 wherein

said plurality of second notches extend to a height one-half the height of said posts.

5. A bus bar as recited in claim 3, further comprising:

a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height one-half the height of said posts.

6. A bus bar as recited in claim 3, further comprising:

a plurality of second notches in the mounting edge surface of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts; and

a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and thus transverse to the direction of said plurality of second notches and intersecting same, and of a height no greater than one-half the height of said posts.

7. A bus bar as recited in claim 6, wherein:

said first-notches extend to one-third the height dimension of the bar; and

each of said second and third pluralities of notches is of a height approximately one-half the height of said posts.

2. A bus bar comprising:

an elongated bar of metallic, conductive material defining a longitudinal axis and having a generally rectangular cross-section in a plane perpendicular to the longitudinal axis and parallel, major rectangular surfaces of common, predetermined length and height dimensions respectively parallel to and transverse to the longitudinal axis and parallel minor surfaces extending between the major surfaces and corresponding to the thickness dimension of the bar, one of said minor surfaces comprising a longitudinal mounting edge of the elongated bar; and

said longitudinal mounting edge and adjacent portions of said parallel major rectangular surfaces of said bar comprising a plurality of posts defined by a corresponding plurality of first notches extending through the full thickness of the bar, transversely from the longitudinal mounting edge thereof to no greater than one-third the height dimension of the bar, said posts and first notches having respective, relative width dimensions in a direction parallel to the longitudinal axis of no greater than 10 to 1; and

a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height no greater than one-half the height of said posts.

8. In combination:

a circuit board having a planar mounting surface;

an elongated terminal pad on the planar mounting surface of said circuit board; and

an elongated bus bar of metallic, conductive material defining a longitudinal axis having a generally rectangular cross-section in a plane perpendicular to the longitudinal axis and parallel, major rectangular surfaces of common, predetermined length and height dimensions respectively parallel to and transverse to the longitudinal axis and parallel minor surfaces extending between the major surfaces and corresponding to the thickness dimension of the bar, one of said minor surfaces comprising a longitudinal mounting edge of the elongated bar;

said longitudinal mounting edge and adjacent portions of said parallel major rectangular surfaces of said bar comprising a plurality of posts defined by a corresponding plurality of first notches extending through the full thickness of the bar, transversely from the longitudinal mounting edge thereof to no greater than one-third the height dimension of the bar, said posts and first notches having respective, relative width dimensions in a direction parallel to the longitudinal axis of no greater than 10 to 1;

means for securing the longitudinal mounting edge surfaces of said posts to the elongated terminal pad of the circuit board,

said securing means comprising soldered connections between the longitudinal mounting edge surfaces of said posts and said elongated terminal pads;

a plurality of second notches in said longitudinal mounting edge surfaces of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts; and

a plurality of third notches in said longitudinal edge mounting surfaces of said posts, extending in a direction parallel to the longitudinal axis and thus transverse to the direction of said plurality of second notches and intersecting same, and of a height no greater than one-half the height of said posts.

9. The combination of claim 8, wherein:

said securing means comprises soldered connections received partially within said second and third pluralities of notches and between the longitudinally mounting edge surfaces of said posts and said elongated terminal pad.

10. A method of forming a bus bar comprising:

providing an elongated bar of metallic, conductive material defining a longitudinal axis having a generally rectangular cross-section in a plane perpendicular to the longitudinal axis and parallel, major rectangular surfaces of common, predetermined length and height dimensions respectively parallel to and transverse to the longitudinal axis and parallel minor surfaces extending between the major surfaces and corresponding to the thickness dimension of the bar;

defining a longitudinal edge surface of the elongated bar as the longitudinal mounting edge of the bar; and

forming a plurality of first notches extending through the thickness dimension of the bar transversely to the longitudinal axis and from the longitudinal mounting edge surface thereof to no greater than one-third the height dimension of the bar at longitudinally spaced positions so as to define corresponding posts, said posts and first notches having respective relative width dimensions in a direction parallel to the longitudinal axis of 10 to 1.

11. The method of claim 10, further comprising:

forming a plurality of second notches in the longitudinal mounting edge surfaces of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts.

12. A method as recited in claim 10, further comprising:

forming a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height no greater than one-half the height of said posts.

13. A method as recited in claim 10, further comprising:

forming a plurality of second notches in the longitudinal mounting edge surfaces of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts; and

forming a plurality of third notches in said longitudinal mounting surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height no greater than one-half the height of said posts.

14. A method of forming an improved bus bar of a given metallic conductive material and having a longitudinal axis and a generally rectangular cross-section, defined by the height and thickness dimensions of the bus bar, in a plane perpendicular to the longitudinal axis, the improved bus bar having, selectively, an increased value of maximum current carrying capacity and/or a reduced value of rigidity in a plane including the longitudinal axis and parallel to the height dimension of the bus bar, relative to a bus bar of the given, metallic conductive material having nominal said height and thickness dimensions and a correspondingly defined, nominal cross-sectional area determining maximum current carrying capacity and rigidity values thereof, one of the longitudinally extending edges corresponding to the thickness dimension of each of said improved bus bar and the bus bar of said nominal dimensions comprising a longitudinal mounting edge surface of the corresponding bus bar, comprising:

selecting an elongated bar of the given, metallic conductive material, having an increased cross-sectional area relative to the nominal cross-sectional area; and

forming a plurality of first notches extending through the full thickness dimension of the elongated bar, transversely from the longitudinal mounting edge surfaces thereof at longitudinally spaced positions so as to define corresponding posts, said posts and first notches having respective, relative width dimensions in a direction parallel to the longitudinal axis of no greater than 10 to 1 and the first notches extending in the direction of the height dimension of the bar by an amount sufficient to reduce the rigidity value of the elongated bar to a value no greater than the rigidity value of a bus bar of the nominal cross-sectional area.

15. The method of claim 14, further comprising:

forming a plurality of second notches in the longitudinal mounting edge surfaces of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts.

16. A method as recited in claim 14, further comprising:

forming a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height no greater than one-half the height of said posts.

17. A method as recited in claim 14, further comprising:

forming a plurality of second notches in the longitudinal mounting edge surfaces of said posts extending transversely to the longitudinal axis and of a height no greater than one-half the height of said posts; and

forming a plurality of third notches in said longitudinal mounting edge surfaces of said posts, extending in a direction parallel to the longitudinal axis and of a height no greater than one-half the height of said posts.

18. A method of forming an improved bus bar of a given, metallic conductive material and having a longitudinal axis and a generally rectangular cross-section, defined by the height and thickness dimensions of the bus bar, in a plane perpendicular to the longitudinal axis, the improved bus bar having, selectively, an increased value of maximum current carrying capacity and/or a reduced value of rigidity in a plane including the longitudinal axis and parallel to the height dimension of the bus bar, relative to a bus bar of the given, metallic conductive material having nominal said height and thickness dimensions and a correspondingly defined, nominal cross-sectional area determining a maximum current carrying capacity and rigidity values thereof, one of the longitudinally extending edges corresponding to the thickness dimension of each of said improved bus bar and the bus bar of said nominal dimensions comprising a longitudinal mounting edge surface of the corresponding bus bar, comprising:

selecting an elongated bar of the given, metallic conductive material and having an increased cross-sectional area relative to the nominal cross-sectional area; and

forming a plurality of notches extending through the full thickness dimension of the elongated bar, transversely from the longitudinal mounting edge surface thereof to a height (h₁) relative to the height dimension (H) of the bar, wherein (h₁) is not greater than one-third (H) and, for a given thickness dimension (D) of the elongated bar, is selected in accordance with reducing the rigidity of the bar in a plane parallel to the major surfaces of the bar in proportion to the factor (H-h₁)³ while maintaining a required maximum value of current carrying capacity determined in accordance with the proportional relationship (H-h₁)×

D.