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EP-3890462-B1 - WEDGE LOCK SUPPORT COLUMNS IN ELECTRONIC CHASSIS

EP3890462B1EP 3890462 B1EP3890462 B1EP 3890462B1EP-3890462-B1

Inventors

  • Nayak, Hebri Vijayendra

Dates

Publication Date
20260506
Application Date
20210310

Claims (11)

  1. An electronic chassis (100) for supporting printed wiring boards assemblies, PWB assemblies, each having a PWB (310) and several electronic components (320) and a stiffener (330) that provides structural support to the PWB assembly (300) and acts as a heat sink, the electronic chassis comprising: a first side (105a); a second side (105b) opposite the first side; a first set of wedge lock support columns (110) machined on the first side; and a second set of wedge lock support columns (110) machined on the second side, wherein each wedge lock support column of the first set of wedge lock support columns and the second set of wedge lock support columns is machined as a solid square wave shape; wherein: opposite sides of each PWB assembly (300) comprise a ledge on which a wedge lock (340) made up of wedges (510) is formed to support each PWB assembly between two wedge lock support columns (110) that are on opposite sides of the PWB assembly; each wedge lock support column of the first set of wedge lock support columns has a corresponding mirror image among the second set of wedge lock support columns; and a distance between adjacent wedge lock support columns (110) accommodates a depth, d, of the corresponding wedge lock (340) and a thickness of the ledge supporting the wedge lock (340), and the distance between adjacent wedge lock support columns (110) does not exceed the full deployed depth of the wedge lock (340), which is the depth after normal forces are applied to the wedges (510); the normal forces on adjacent wedges (510) of the wedge lock (340) are in opposite directions towards adjacent wedge lock support columns, the wedge lock support columns (110) are shaped and sized to support the wedges (510) that are pushed away from the ledge on which the wedge lock (340) is disposed, as well as to support the ledge and the wedges (510) that are pushed toward the ledge; the wedge lock support columns (110) have the square wave shape along a longitudinal direction of the sides of the electronic chassis (100); wherein the square wave shape provides unsupported sections of the wedge lock support columns, minimizes the effect of the normal forces on a fillet region (120) from which the wedge lock support columns protrude on the first and second sides into a volume of the electronic chassis, and enhances heat transfer that occurs from a PWB assembly (110) to the wedges (510) and the wedge lock support columns (110).
  2. The electronic chassis according to claim 1, wherein each wedge lock support column of the first set of wedge lock support columns is a same distance from a third side of the electronic chassis as the corresponding mirror image on the second side, and wherein the third side is between the first side and the second side and is perpendicular to the first side and to the second side.
  3. The electronic chassis according to claim 1, wherein each wedge lock support column of the first set of wedge lock support columns protrudes from a fillet region on the first side into the volume of the electronic chassis.
  4. The electronic chassis according to claim 1, wherein each wedge lock support column of the second set of wedge lock support columns protrudes from a fillet region on the second side into the volume of the electronic chassis.
  5. The electronic chassis according to any preceding claim, wherein a minimum and maximum distance between adjacent wedge lock support columns is defined by a thickness of a wedge lock to be inserted between the adjacent wedge lock support columns in the electronic chassis, and wherein a number of the first set of wedge lock support columns and a number of the second set of wedge lock support columns define a number of printed wiring boards to be inserted in the electronic chassis.
  6. The electronic chassis according to any preceding claim, wherein a thickness of each wedge lock support structure is based on structural requirements.
  7. A method of fabricating an electronic chassis (100) for supporting printed wiring boards assemblies, PWB assemblies, each having a PWB (310) and several electronic components (320) and a stiffener (330) that provides structural support to the PWB assembly (300) and acts as a heat sink, the method comprising: forming a first set of wedge lock support columns (110) machined on a first side (105a) of the electronic chassis; and forming a second set of wedge lock support columns (110) machined on a second side (105b) of the electronic chassis, wherein each wedge lock support column of the first set of wedge lock support columns and the second set of wedge lock support columns is machined as a solid square wave shape; wherein: opposite sides of each PWB assembly (300) comprise a ledge on which a wedge lock (340) made up of wedges (510) is formed to support each PWB assembly between two wedge lock support columns (110) that are on opposite sides of the PWB assembly; each wedge lock support column of the first set of wedge lock support columns has a corresponding mirror image among the second set of wedge lock support columns; and a distance between adjacent wedge lock support columns (110) accommodates a depth, d, of the corresponding wedge lock (340) and a thickness of the ledge supporting the wedge lock (340) and the distance between adjacent wedge lock support columns (110) does not exceed the full deployed depth of the wedge lock (340), which is the depth after normal forces are applied to the wedges (510); the normal forces on adjacent wedges (510) of the wedge lock (340) are in opposite directions towards adjacent wedge lock support columns, the wedge lock support columns (110) are shaped and sized to support the wedges (510) that are pushed away from the ledge on which the wedge lock (340) is disposed, as well as to support the ledge and the wedges (510) that are pushed toward the ledge; the wedge lock support columns (110) have the square wave shape along a longitudinal direction of the sides of the electronic chassis (100); wherein the square wave shape provides unsupported sections of the wedge lock support columns, minimizes the effect of the normal forces on a fillet region (120) from which the wedge lock support columns protrude on the first and second sides into a volume of the electronic chassis, and enhances heat transfer that occurs from a PWB assembly (110) to the wedges (510) and the wedge lock support columns (110).
  8. The method according to claim 7, wherein the forming the first set of wedge lock support columns and the forming the second set of wedge lock support columns includes forming each wedge lock support column of the first set of wedge lock support columns at a same distance from a third side of the electronic chassis as the corresponding mirror image on the second side, and preferably wherein the third side is between the first side and the second side and is perpendicular to the first side and to the second side.
  9. The method according to claim 7, wherein the forming the first set of wedge lock support columns includes each wedge lock support column of the first set of wedge lock support columns protruding from a fillet region on the first side into the volume of the electronic chassis.
  10. The method according to claim 7, wherein the forming the second set of wedge lock support columns includes each wedge lock support column of the second set of wedge lock support columns protruding from a fillet region on the first side into the volume of the electronic chassis.
  11. The method according to claim 7, wherein the forming the first set of wedge lock support columns and the second set of wedge lock support columns includes a minimum and maximum distance between adjacent wedge lock support columns being defined by a thickness of a wedge lock to be inserted between the adjacent wedge lock support columns in the electronic chassis, and wherein the forming the first set of wedge lock support columns and the second set of wedge lock support columns includes a number of the wedge lock support columns on the first side and the second side defining a number of printed wiring boards to be inserted in the electronic chassis, and wherein the forming the first set of wedge lock support columns and the second set of wedge lock support columns includes a thickness of each wedge lock support structure being based on structural requirements.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63/003,458 filed April 1, 2020. BACKGROUND Exemplary embodiments pertain to the art of electronics packaging and, in particular, to wedge lock support columns in an electronic chassis. In many applications, a number of electronic components are arranged and interconnected on a printed wiring board (PWB) assembly. A number of such PWB assemblies can then be mounted in an electronic chassis. Wedge locks are used to lock the PWB assemblies in place in the electronic chassis. US 2011/058335 relates to a conduction-cooled enclosure. CN 209 949 677 U relates to joint design of circuits. BRIEF DESCRIPTION In one embodiment, an electronic chassis is provided in claim 1 and includes a first side, and a second side opposite the first side. The electronic chassis also includes a first set of wedge lock support columns machined on the first side, and a second set of wedge lock support columns machined on the second side. Each wedge lock support column of the first set of wedge lock support columns and the second set of wedge lock support columns is machined as a solid shape. Each wedge lock support column of the first set of wedge lock support columns has a corresponding mirror image among the second set of wedge lock support columns. Additionally or alternatively, in this or other embodiments, each wedge lock support column of the first set of wedge lock support columns is a same distance from a third side of the electronic chassis as the corresponding mirror image on the second side. Additionally or alternatively, in this or other embodiments, the third side is between the first side and the second side and is perpendicular to the first side and to the second side. The continuous shape of each wedge lock support column is a shape of a square wave. Additionally or alternatively, in this or other embodiments, each wedge lock support column of the first set of wedge lock support columns protrudes from a fillet region on the first side into a volume of the electronic chassis. Additionally or alternatively, in this or other embodiments, each wedge lock support column of the second set of wedge lock support columns protrudes from a fillet region on the second side into a volume of the electronic chassis. Additionally or alternatively, in this or other embodiments, a minimum and maximum distance between adjacent wedge lock support columns is defined by a wedge lock to be inserted in the electronic chassis. Additionally or alternatively, in this or other embodiments, a number of the first set of wedge lock support columns and a number of the second set of wedge lock support columns define a number of printed wiring boards to be inserted in the electronic chassis. Additionally or alternatively, in this or other embodiments, a thickness of each wedge lock support structure is based on structural requirements. In another embodiment, a method is provided in claim 7 and includes forming a first set of wedge lock support columns machined on a first side of the electronic chassis. The method also includes forming a second set of wedge lock support columns machined on a second side of the electronic chassis. Each wedge lock support column of the first set of wedge lock support columns and the second set of wedge lock support columns is machined as a solid shape. The forming the first set of wedge lock support columns and the forming the second set of wedge lock support columns includes forming a mirror image among the second set of wedge lock support columns for each wedge lock support column of the first set of wedge lock support columns. Additionally or alternatively, in this or other embodiments, the forming the first set of wedge lock support columns and the forming the second set of wedge lock support columns includes forming each wedge lock support column of the first set of wedge lock support columns at a same distance from a third side of the electronic chassis as the corresponding mirror image on the second side. Additionally or alternatively, in this or other embodiments, the third side is between the first side and the second side and is perpendicular to the first side and to the second side. The forming each wedge lock support column includes forming each continuous shape of each wedge lock support column as a shape of a square wave. Additionally or alternatively, in this or other embodiments, the forming the first set of wedge lock support columns includes each wedge lock support column of the first set of wedge lock support columns protruding from a fillet region on the first side into a volume of the electronic chassis. Additionally or alternatively, in this or other embodiments, the forming the second set of wedge lock support columns includes each wedge lock support column of the second set of wedge lock support columns protruding from a fillet region on the first side into a volume of the electronic chass