Fastener assembly for circuit board

Abstract

The fastener system of the present invention has interconnecting parts for fastening electronic components that can be joined by a snap fit when the fastener parts are pressed into a retainer. The fastener system has a fastener stud having a planar base at its bottom and an upwardly extending shank with a reduced diameter neck adjacent the base. The fastener stud has a spherical ball portion with a flat, planar upper surface at its distal upper end. The fastener stud engages a retainer having the planar base and fixed, opposing, resilient arms extending perpendicularly from the base centered about the axis of rotation. The arms preferably have compound-shaped inner surfaces symmetrical about the axis of rotation. The inner surfaces have a cylindrical portion adjacent the base and a spherical portion adjacent the distal ends of the arms.

Description

[Technical Field]

[0001] This application is a PCT patent application filed on December 11, 2020, related to U.S. Provisional Patent Application No. 63 / 124,433, entitled "Fastening Device and Assembly for Circuit Boards," and claims priority to that patent application.

[0002] The present invention relates to a two-part fastener system having separable components that releasably join together. Specifically, the present invention relates to a surface mount metal fastener of the type that joins circuit boards in spaced apart relation to one another. [Background technology]

[0003] In the field of circuit board fasteners, it is known to join two circuit boards in spaced apart relationship using fasteners that are soldered or otherwise secured to the circuit boards. For a variety of reasons, these fasteners have various deficiencies and do not meet the requirements of modern high-speed robotic assembly technology, including compatibility with pick-and-place robotics, tape-and-reel delivery to the mounting location, and circuit board surface-mount solder technology. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION Therefore, a primary object of the present invention is to solve the above problems in the field of circuit board packaging. [Means for solving the problem]

[0005] As will be explained below with reference to the drawings and description of one preferred embodiment of the invention, the system comprises a fastener pair consisting of two separate mating components, one of which is a fastener stud with a ball end, and the other of which is a retainer that receives the ball end by a snap fit. These components utilize surface mount technology in an effective manner that provides the following benefits: 1. The two components of the fastener assembly pair are mounted separately but can be set on a central axis. 2. The fastener pair can be assembled and disassembled manually in several cycles without the need for tools. 3. The fastener pair can be assembled at an angle (perpendicular or non-perpendicular approach angle). 4. The fastener pair is available in tape and reel delivery and can be mounted by SMT (solderable surface mount technology). 5. The component can act as a spacer to strictly maintain the height tolerance during assembly. 6. The fastener pair can be oriented at a predetermined angle relative to the assembly axis when installed.

[0006] More specifically, Applicant's invention relates to two interconnecting members for fastening electronic components that can be joined by a snap fit when the fastener components are compressed into a retainer. The fastener system includes a fastener stud with a planar base at its bottom and an upwardly extending shank with a reduced-diameter neck portion adjacent the base. The stud has a spherical ball portion with a planar upper surface at its distal upper end. The fastener stud engages a retainer having a planar base, which has fixed, opposing, resilient arms extending perpendicularly from the base centered about an axis of rotation. The arms preferably have inner surfaces of a compound shape symmetrical about the axis of rotation. The compound surfaces include a cylindrical portion adjacent the base and base and spherical portions adjacent the distal ends of the arms. The retainer and fastener are constructed and arranged so that the fastener is received between the retainer arms by a releasable snap fit. The spherical portion of the inner surface of the retainer arm preferably matches the contour of the fastener ball portion adjacent the fastener neck.

[0007] In some embodiments, the top of the fastener stud abuts the retainer base, so there are only two retainer arms. The retainer base has an outer surface that is planar and perpendicular to the axis, and the outer surface of the fastener base is also planar and perpendicular to the axis. The outer surfaces of the retainer base and fastener base are preferably compatible with surface-mount soldering and pick-and-place handling during the manufacture of electronic components, such as circuit boards, where the fastener and / or retainer are soldered to the electronic component. [Effects of the Invention]

[0008] The inner surface of the retainer base is flat and abuts the top of the fastener, while the ends of the retainer arms are adjacent to the neck portion, and the configuration of each member (or component) located between the spherical portion and the fastener base greatly improves the stability of the joined fastener and retainer.

[0009] Those skilled in the art of electronic fasteners will appreciate other objects and advantages of the present invention from the accompanying drawings and the following description illustrating embodiments of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front elevational view showing the fastener / retainer in an assembled state. [Figure 2] FIG. 2 is a cross-sectional view of FIG. [Figure 3] FIG. 3 is a front elevational view showing the retainer. [Figure 4] FIG. 4 is a front elevational view showing the fastener stud. [Figure 5-7] 5, 6 and 7 are top front perspective views of the retainer elements shown in isolation and in various rotational positions. [Figure 8] FIG. 8 is a side elevational view showing the fastener element and retainer element in the orthogonal (or right-angle) assembly position. [Figure 9] FIG. 9 is a side elevational view showing the non-orthogonal assembly position of the fastener element and the retainer element prior to assembly. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 and 2, the two main elements of the present invention, a retainer 11 and a fastener stud 13, are shown in an assembled state. The retainer has flexible, resilient arms 15 that capture the spherical ball end 17 of the fastener shank with a non-destructive, releasable snap fit. When the arms 15 interact with the fastener's spherical surface, they bend and receive the fastener shank when compressed. The arms are sufficiently resilient to return to their resting assembled position, shown in cross section in FIG. 2. The ends of the arms are located adjacent the neck of the fastener stud and between the spherical portion of the fastener stud and its base.

[0012] Referring to Figure 3, the retainer 11 is shown in isolation. The retainer 11 has a planar base 25 and fixed, opposing, resilient arms 15 extending perpendicularly from the base 25 centered about the axis of rotation 14. The arms have compound shaped inner surfaces symmetrical about the axis, consisting of a cylindrical portion 27 adjacent the base 25 and a spherical portion 29 adjacent the circular distal end 31 of the arm. The base 25 has a flat bottom surface 26, which laterally captures the stud over a range of axial spacing.

[0013] As shown in FIG. 4, the fastener stud has a shank portion extending upward from a base 19, further comprising a neck portion 21 and a partially spherical ball end 17. The fastener stud has a flat top 33 and a flat bottom 20. When assembled, each portion aligns with the flat top 33 of the fastener's spherical portion 17, which abuts flush with the planar inner surface 35 of the retainer's base 25, as shown in FIG. 1. This configuration allows the bases 25 and 19 of the individual elements at their outer surfaces 26 and 20, respectively, to fix the height of the spacer relative to the mating structure, such as a separately mounted circuit board. The abutting mating flat surfaces improves the stability of the components mating with the outer surface of the interconnected fastener / retainer assembly by providing resistance to off-axis tipping. The retainer 11 can rotate about an axis of rotation defined by the axis 14, as can be seen in FIG. 3.

[0014] The flat surfaces shown in Figures 3 and 4 allow for the SMT (surface mount technology) compatible aspect of the present invention. Surfaces 35, 26, 33, and 20 shown in these figures are the primary pick-and-place surfaces where parts are translated by applying a vacuum. If the vacuum nozzle does not fit between the arms of the retainer, a patch can be applied to the top of the arms and that surface can be used for manipulation. SMT compatibility allows for soldering to the exterior surfaces 26 and 20 of bases 25 and 19, respectively.

[0015] Different orientations of the retainer are shown in Figures 5, 6, and 7. With the present invention, the assembly can be oriented with the retainer at any orientation around the assembly axis, as long as the ball-end fasteners are axially aligned. This eliminates the need for precise alignment when placing parts on the PCB.

[0016] Referring to Figures 8 and 9, Figure 8 illustrates one embodiment of an orthogonal assembly that results when assembly is accomplished by press-fitting the retainer 11 and fastener stud 13 along the assembly axis, as indicated by the directional arrows. Figure 9 illustrates a non-orthogonal assembly that results when the components are assembled by press-fitting at an oblique angle relative to the vertical axis of rotation of the retainer. This non-orthogonal assembly is achieved by axially circular contact points between the retainer and the circular surfaces of the fastener balls.

[0017] From the above description, it should be clear to those skilled in the art that the effects and objects of the present invention have been achieved. It should be noted that the embodiment described above is merely one possible embodiment of the present invention. Various other embodiments utilizing the basic operating principles of the fastener system described above are also possible, and all of them do not depart from the scope and spirit of the invention as defined in the claims and their equivalents. [Explanation of symbols]

[0018] 11 Retainer 13 zipper studs 14 Rotation axis, axis line 15 Opposing elastic arms, elastic arms 17 Spherical part of fastener, ball end 19 Base 20 External surface, bottom surface, surface 21 Neck 25 Base, planar base 26 External surface, bottom surface, surface 27 Cylindrical section 29 Spherical part 31 Circular Distal End 33 Upper, surface, flat upper part 35. Surface, planar inner surface

Claims

1. 1. A fastener assembly for joining electronic components, comprising two interconnection elements, a fastener stud having a flat base at its bottom, with a neck portion of reduced diameter adjacent to the flat base, and a shank portion extending upwardly and having a flat upper, spherical ball portion; a retainer having only two fixed, opposing, resilient arms extending perpendicularly from a flat base centered about an axis of rotation, the arms comprising a cylindrical portion adjacent the base and a spherical portion adjacent a distal end of the arms and surrounding the fastener stud, the arms having compound shaped inner surfaces symmetrical about the axis; The retainer arms and fastener studs are joined by a non-destructive, releasable snap fit, and the upper flat surface of the fastener stud abuts the base of the retainer flush with the inner surface of the flat base.

2. 2. The fastener assembly of claim 1, wherein the number of said arms is only two.

3. 2. The fastener assembly of claim 1, wherein the outer surface of the base of said retainer is planar and perpendicular to said axis.

4. 4. The fastener assembly of claim 3, wherein the outer surface of the base of said fastener stud is planar and perpendicular to said axis.

5. 5. The fastener assembly of claim 4, wherein the outer surfaces of the retainer and the base of the fastener stud are compatible with surface mount soldering and pick and place transport.

6. The fastener assembly of claim 5 , wherein the fastener stud and / or the retainer are soldered to an electronic component.

7. 7. The fastener assembly of claim 6, wherein said electronic component is a circuit board.

8. 2. The fastener assembly of claim 1, wherein the ends of the arms are adjacent the neck of the fastener stud and are located between the spherical ball portion of the fastener stud and the base of the fastener stud.

9. 9. The fastener assembly of claim 8, wherein the inner end surface of said arm matches the contour of the ball portion of said fastener stud.

10. 9. The fastener assembly of claim 8, wherein the distal ends of said retainer arms are axially rounded and match the contour of said neck.

11. 10. The fastener assembly of claim 9, wherein the fastener stud and the retainer are configured to mate when the fastener stud is pressed against the arm of the retainer at an angle relative to the axis of rotation.

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