Fastener for fastening circuit card

Abstract

The invention relates to a fastener for fastening a circuit card. A fastener includes: a head; a first pin extending from the head along the longitudinal axis, the first pin including a surface feature configured to engage a first circuit card assembly; and a second pin extending from the head in an opposite direction to the first pin, the second pin including a stopper wall and a plurality of deflectable arms configured to deflect toward the longitudinal axis when inserted into a second circuit card assembly to couple the second pin to the second circuit card assembly. A stopper wall extends from at least one of the plurality of deflectable arms away from the longitudinal axis and is configured to contact a second circuit card assembly when the plurality of deflectable arms are coupled to the second circuit card assembly.

Description

Technical Field

[0001] This specification generally relates to fasteners, and more particularly to fasteners for securing a circuit card assembly to a metal casting. Background Art

[0002] Screws are used to attach one component to another in various manufacturing processes. When fastening components together, manufacturing using screws requires controlling the torque value. Controlling torque can be difficult to replicate and increases the time required for manufacturing. Additionally, over-tightening the screws can damage the components being attached together. Thus, alternative fasteners for attaching two components together are needed. Summary of the Invention

[0003] In one embodiment, a fastener for securing a circuit card assembly includes: a head having a first radius; a first pin having a second radius less than the first radius, the first pin extending from the head along a longitudinal axis, the first pin including an outer surface circumferentially surrounding the longitudinal axis and a surface feature extending on the outer surface between the head and the end of the first pin, the surface feature being configured to engage a first circuit card assembly; and a second pin extending from the head along the longitudinal axis in a direction opposite to the first pin, the second pin including a stop wall and a plurality of deflectable arms configured to deflect toward the longitudinal axis when inserted into a second circuit card assembly to couple the second pin to the second circuit card assembly, and the stop wall extending away from the longitudinal axis from at least one of the plurality of deflectable arms, the stop wall being configured to contact the second circuit card assembly when the plurality of deflectable arms are coupled to the second circuit card assembly.

[0004] In another embodiment, a fastener for securing a circuit card assembly includes: a head having a first radius; a first pin having a second radius less than the first radius, the first pin extending from the head along a longitudinal axis, the first pin including an outer surface circumferentially surrounding the longitudinal axis and a surface feature extending on the outer surface from the head toward the end of the first pin, the surface feature including at least one of: a plurality of barbs, helical knurling, and a plurality of threads, and the surface feature being configured to engage a first circuit card assembly; and a second pin extending from the head along the longitudinal axis in a direction opposite to the first pin, the second pin including a plurality of deflectable arms configured to deflect toward the longitudinal axis when inserted into a second circuit card assembly to couple the second pin to the second circuit card assembly.

[0005] These features and additional features provided by the embodiments described herein will be more fully understood in conjunction with the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The embodiments illustrated in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of illustrative embodiments can be understood when read in conjunction with the following drawings, in which like structures are indicated by like reference numerals, and in which:

[0007] Figure 1 A perspective view of a fastener for coupling a pair of circuit card assemblies and a circuit card housing, in accordance with one or more embodiments shown and described herein;

[0008] Figure 2A A perspective view of an example fastener, in accordance with one or more embodiments shown and described herein;

[0009] Figure 2B A cross-sectional side view of an example fastener being inserted into a circuit card housing, in accordance with one or more embodiments shown and described herein;

[0010] Figure 3 A perspective view of another example fastener, in accordance with one or more embodiments shown and described herein; and

[0011] Figure 4 A perspective view of yet another example fastener, in accordance with one or more embodiments shown and described herein. DETAILED DESCRIPTION

[0012] First, refer to Figure 1, depicts a pair of circuit card assemblies fastened together. The first circuit card assembly 24 is fastened to the second circuit card assembly 26 by a fastener 10 through press-fit engagement. The first circuit card assembly 24 includes a first attachment opening 25, and the second circuit card assembly 26 includes a second attachment opening 27, each attachment opening for receiving a portion of the fastener 10. The first attachment opening 25 may have an opening radius that is less than the radius of at least a portion of the pin 14 of the fastener 10. Alternatively, the first attachment opening 25 may have an opening radius that is greater than the radius of the pin 14, and the first circuit card assembly 24 is attached to the circuit card housing 11 by being positioned between the head 12 of the fastener 10 and the circuit card housing 11. Each circuit card assembly may include a printed circuit board (PCB) and electronic components such as capacitors, transistors, inductors, etc. on the PCB. The pair of circuit card assemblies may be attached to the circuit card housing 11 by inserting the pin of the fastener 10 into an opening in the circuit card housing 11. The pair of circuit card assemblies may be a power card for metering the power supplied to the device and a control card for controlling the operation of the device. The circuit card housing 11 may be formed of any operable material (such as plastic or metal), where the circuit card housing 11 may be a metal casting. In some embodiments, the circuit card housing 11 may be a housing for an electric motor (such as an electric vehicle motor). In additional embodiments, the circuit card housing 11 may be a plastic housing, such as for a steering column, for a circuit card assembly that is smaller than the circuit card assembly for a metal casting. The foregoing examples are merely examples and do not limit the use of the component materials or applications.

[0013] The fastener 10 extends into the first attachment opening 25 of the first circuit card assembly 24, the second attachment opening 27 of the second circuit card assembly 26, and the opening of the circuit card housing 11 to couple the circuit card assemblies to the circuit card housing 11, where the fastener 10 completes the ground path between the pair of circuit card assemblies and the circuit card housing 11, thereby grounding the circuit card assemblies. As shown by the dashed line, the fastener 10 may be inserted into the circuit card assemblies and the circuit card housing 11 along an insertion axis I that extends through the centers of the first attachment opening 25, the second attachment opening 27, and the opening in the circuit card housing 11.

[0014] Now refer to Figure 2A , depicts Figure 1A first embodiment of a fastener 10. The fastener 10 includes a head 12, a first pin 14 extending from the head 12 along a longitudinal axis 30, and a second pin 16 extending from the head 12 along the longitudinal axis 30 in a direction opposite to the first pin 14. The head 12 has a first radius, the first pin 14 has a second radius smaller than the first radius, and the second pin 16 has a third radius smaller than the first radius. The first pin 14 includes an outer surface 18 circumferentially surrounding the longitudinal axis 30 and surface features 20 on the outer surface 18 extending from the head 12 towards the end 22 of the pin 14. The surface features 20 can be at least one of a plurality of barbs, knurling, and a plurality of threads, and are configured to engage a first circuit card assembly 24 and a circuit card housing 11. Figure 2A The depicted fastener 10 includes knurling 60. The knurling 60 includes a plurality of knurls extending from the head 12 to the end 22 of the first pin 12, where the plurality of knurls form a helix and each of the plurality of knurls circumferentially surrounds the longitudinal axis 30 at least partially. When the fastener 10 is inserted into an attachment opening, as the fastener 10 moves into the attachment opening, the knurling 60 can cause the fastener 10 to rotate. When the fastener 10 is removed from the attachment opening, the knurling 60 similarly causes the fastener 10 to rotate. However, during removal, a tool (such as a claw head hammer) provides a normal force to the head 12 of the fastener 10, thereby resisting the rotation of the fastener 10 and increasing the force required to remove the fastener 10 compared to insertion. The knurling 60 can include any operable number of knurls, such as 1, 20, between 1 and 20, or more than 20 knurls. When viewed in a side view, each knurl can be angled relative to the longitudinal axis 30. In some embodiments, the angle can be between 10° and 80°, more specifically, the angle is between 25° and 40° (including the endpoints).

[0015] The fastener 10 can include a chamfer 42 at the end 22 of the first pin 14, the chamfer having an angle between 25° and 40° relative to the longitudinal axis 30. The fastener 10 can also include a length of the first pin 14 that is located between the surface features 20 and the end 22 of the pin 14 and does not include the surface features 20, where the length of the first pin 14 without the surface features 20 extends from the surface features 20 to the chamfer 42. The fastener 10 can include a zinc coating (or other coating that allows grounding) to prevent corrosion.

[0016] The second pin 16 of the fastener 10 may include a stop wall 32, a plurality of deflectable arms 36, and a base 44 from which the deflectable arms 36 extend. The plurality of deflectable arms 36 may be configured to deflect toward the longitudinal axis 30 when inserted into the second circuit card assembly 26 to couple the second pin 16 to the second circuit card assembly 26 by press - fit engagement. The stop wall 32 may extend from at least one of the plurality of deflectable arms 36 and may extend away from the longitudinal axis 30 from each of the deflectable arms 36 to radially surround the longitudinal axis 30. The stop wall 32 is configured to contact the second circuit card assembly 26 when the plurality of deflectable arms 36 are coupled to the second circuit card assembly 26 to space the second circuit card assembly 26 from the first circuit card assembly 24 by a predetermined distance.

[0017] Each of the plurality of deflectable arms 36 may include an outer surface 37 having an outwardly tapered section 38 and an inwardly tapered section 40, the distance of the outwardly tapered section from the longitudinal axis 30 increasing as the outer surface 37 moves from the stop wall 32 toward the end 22, and the distance of the inwardly tapered section from the longitudinal axis 30 decreasing as the outer surface 37 moves from the outwardly tapered section 38 toward the end 22. The inwardly tapered section 40 may engage a second attachment opening 27 in the second circuit card assembly 26 to couple the fastener 10 to the second circuit card assembly 26. Each of the plurality of deflectable arms 36 may include a bevel 42 at the end 22 on the inner edge of the deflectable arm 36 closest to the longitudinal axis 30. The plurality of deflectable arms 36 may include any operable number of deflectable arms 36, such as, for example, four deflectable arms 36.

[0018] Reference Figure 2B , an insertion tool 50 may be used to insert the fastener 10 into the circuit card housing 11. The insertion tool 50 may include a body 52 that defines a cavity 54 having a first inner section 56 and a second inner section 58, the first inner section having a first radius and the second inner section having a second radius greater than the first radius, wherein the second inner section 58 is positioned between the first inner section 56 and the open end 57 of the cavity 54. The cavity 54 of the insertion tool 50 may also include a tapered section 59 between the first inner section 56 and the second inner section 58 for contacting and engaging the insertion section 46 of the second pin 16. The second pin 16 may include an insertion section 46 at the end of the base 44 from which the plurality of deflectable arms 36 extend, wherein the insertion section 46 includes a tapered surface 48.

[0019] Now reference Figure 3 , another embodiment of a fastener 10' is depicted. In addition to the surface features 20', the fastener 10' may include the above - referenced Figure 2AEach of the features described. Thus, for the sake of brevity, similar features will not be described again. The surface feature 20' of the fastener 10' can be a plurality of barbs 62, where each barb of the plurality of barbs 62 circumferentially surrounds the longitudinal axis 30, and the plurality of barbs 62 are spaced apart along the longitudinal axis 30. The plurality of barbs 62 are arranged sequentially along the longitudinal axis 30. The plurality of barbs 62 can include any operable number of barbs, including 1, 20, or any number in between, and more specifically includes 12 barbs. The barbs can each have a uniform thickness (e.g., the distance along the longitudinal axis 30) and have a uniform spacing between the barbs along the longitudinal axis 30.

[0020] Now referring to Figure 4 , another embodiment of the fastener 10'' is depicted. In addition to the surface feature 20'', the fastener 10'' can include each of the features described above with reference to Figure 2A and Figure 3 Each of the features described. Thus, for the sake of brevity, similar features will not be described again. The surface feature 20'' of the fastener 10'' can be a threaded surface 64 similar to a screw or bolt such that the fastener 10'' can be screwed into the circuit card housing 11 to couple to the circuit card housing 11. In such embodiments, the head 12 of the fastener 10'' can be a hexagonal shape or another shape that allows a tool to clamp the head 12 and rotate the fastener 10''.

[0021] It should be noted that the terms "substantially" and "about" can be used herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also used herein to represent the degree to which a quantitative representation can vary from the stated reference without causing a fundamental change in the basic function of the subject matter being discussed.

[0022] Although specific embodiments have been shown and described herein, it should be understood that various other changes and modifications can be made without departing from the spirit and scope of the claimed subject matter. Additionally, although various aspects of the claimed subject matter have been described herein, these aspects need not be used in combination. Thus, the appended claims are intended to cover all such changes and modifications within the scope of the claimed subject matter.

Claims

1. A fastener for fastening a circuit card assembly, the fastener comprising: A head having a first radius; A first pin having a second radius smaller than the first radius, the first pin extending from the head along a longitudinal axis, the first pin including an outer surface circumferentially surrounding the longitudinal axis and a surface feature extending on the outer surface between the head and the end of the first pin, the surface feature being configured to engage a first circuit card assembly; And A second pin extending from the head along the longitudinal axis in a direction opposite to the first pin, the second pin including a stop wall and a plurality of deflectable arms configured to deflect toward the longitudinal axis when inserted into a second circuit card assembly to couple the second pin to the second circuit card assembly, and the stop wall extending from at least one of the plurality of deflectable arms away from the longitudinal axis, the stop wall being configured to contact the second circuit card assembly when the plurality of deflectable arms are coupled to the second circuit card assembly.

2. The fastener according to claim 1, wherein, Each of the plurality of deflectable arms includes an outer surface having an outwardly tapered section and an inwardly tapered section, the distance from the outwardly tapered section to the longitudinal axis increasing as the outer surface moves from the stop wall toward the end, and the distance from the inwardly tapered section to the longitudinal axis decreasing as the outer surface moves from the outwardly tapered section toward the end.

3. The fastener according to claim 1, wherein, Each of the plurality of deflectable arms includes a bevel at the end on the inner edge of the deflectable arm closest to the longitudinal axis.

4. The fastener according to claim 1, wherein, The plurality of deflectable arms includes four deflectable arms.

5. The fastener according to claim 1, wherein, The stop wall extends from each of the plurality of deflectable arms to radially surround the longitudinal axis.

6. The fastener according to claim 1, wherein, The second pin further includes a base from which the plurality of deflectable arms extend.

7. The fastener according to claim 6, wherein, The base includes an insertion section at the end of the base from which the plurality of deflectable arms extend, the insertion section including a tapered surface.

8. An insertion tool for inserting the fastener according to claim 1, the insertion tool including a body defining a cavity having a first inner section and a second inner section, the first inner section having a first radius, the second inner section having a second radius greater than the first radius, and the second inner section being positioned between the first inner section and the open end of the cavity.

9. The fastener according to claim 8, wherein, The cavity of the insertion tool further includes a tapered section between the first inner section and the second inner section for contacting and engaging the insertion section of the second pin, and the second pin includes a base from which the plurality of deflectable arms extend and an insertion section at the end of the base from which the plurality of deflectable arms extend, the insertion section including a tapered surface.

10. A fastener for fastening a circuit card assembly, the fastener comprising: A head having a first radius; A first pin having a second radius less than the first radius, the first pin extending from the head along a longitudinal axis, the first pin including an outer surface circumferentially surrounding the longitudinal axis and surface features extending on the outer surface from the head toward the end of the first pin, the surface features including at least one of: a plurality of barbs, helical knurling, and a plurality of threads, and the surface features being configured to engage a first circuit card assembly; and A second pin extending from the head along the longitudinal axis in a direction opposite to the first pin, the second pin including a plurality of deflectable arms configured to deflect toward the longitudinal axis when inserted into a second circuit card assembly to couple the second pin to the second circuit card assembly.

11. The fastener according to claim 10, wherein, Each of the plurality of deflectable arms includes an outer surface having an outwardly tapered section and an inwardly tapered section, the distance of the outwardly tapered section from the longitudinal axis increasing as the outer surface moves from a stop wall toward the end, and the distance of the inwardly tapered section from the longitudinal axis decreasing as the outer surface moves from the outwardly tapered section toward the end.

12. The fastener according to claim 10, wherein, The plurality of deflectable arms includes four deflectable arms.

13. The fastener according to claim 10, wherein, A stop wall extends from each of the plurality of deflectable arms to radially surround the longitudinal axis.

14. The fastener according to claim 10, wherein, The second pin further includes a base, and the plurality of deflectable arms extend from the base.

15. The fastener according to claim 14, wherein, The base includes an insertion section at an end of the base from which the plurality of deflectable arms extend, the insertion section including a tapered surface.

16. The fastener according to claim 10, wherein, The plurality of barbs are arranged sequentially along the longitudinal axis.

17. The fastener according to claim 10, further comprising a bevel at an end of the pin, the bevel having an angle between 25° and 40° relative to the longitudinal axis.

18. The fastener according to claim 10, further comprising a length of the pin, excluding the surface features, positioned between the surface features and the end of the pin.

19. The fastener according to claim 10, wherein, The surface features are the plurality of barbs, and each of the plurality of barbs circumferentially surrounds the longitudinal axis, and the plurality of barbs are spaced apart along the longitudinal axis.

20. The fastener according to claim 10, wherein, The surface features are the helical knurling, the helical knurling having a plurality of knurls extending from the head to the end of the pin, the plurality of knurls forming a helix, wherein each of the plurality of knurls at least partially circumferentially surrounds the longitudinal axis.

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