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Browse Prior Art Database

Printed Circuit Board And Component Keying And Retention Design

IP.com Disclosure Number: IPCOM000101867D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 134K

Publishing Venue

IBM

Related People

Davidge, RV: AUTHOR [+2]

Abstract

A printed circuit board (PCB) and component keying design is described whereby specific geometries are used on PCBs and components to facilitate the keying of components for proper alignment. The design also provides automatic retention of components onto the PCB before and during soldering operations.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Printed Circuit Board And Component Keying And Retention Design

       A printed circuit board (PCB) and component keying design
is described whereby specific geometries are used on PCBs and
components to facilitate the keying of components for proper
alignment.  The design also provides automatic retention of
components onto the PCB before and during soldering operations.

      Typically, PCBs are designed to accept various kinds and sizes
of components.  Some components are placed by hand in specific
position and orientations.  A soldering process is applied after
placement so as to secure both electrical and mechanical connections
between various surfaces of the components and the circuit lines on
the PCB.  The concept disclosed herein is an improvement over prior
methods in that it eliminates the need for alignment and position
fixture tools.

      The placement of the components in relation to the circuit
lines is particularly critical.  In prior art, fixtures were often
used to position and retain the components to the PCB prior to and
during soldering.  Often rectangular tabs are used on the components
and inserted into round holes so as to retain the component.  Tabs
are often split in such a manner that when inserted into a hole, the
contraction and subsequent expansion of the tab will produce forces
to retain the components in place.  Other means of retention, such as
screws, are employed.

      When various components, which are similar in appearance but
different in structure or function, are placed on a single PCB,
mislocation of components becomes a major source of difficulty.  The
parts can be similar in appearance and virtually identical when
viewed from the rear, as is required during assembly operations.
This is particularly evident with components, where many different
types of PCBs are assembled on the same manufacturing line and
different types of components and retention devices operate through
identical holes in the PCB.  This can cause components to be
mislocated.

      The concept described herein provides a means of aligning and
positioning components and of retaining them in place before and
during soldering operations.  The concept is compatible with both
circular alignment holes, currently in use, and with rectangular hole
patterns used to permit insertion of only specific types of
components, generally identified by specific patterns of retention
tabs.

      Fig. 1 illustrates how a pair of components are installed on a
PCB in locations prescribed by the hardware. Receptacle-type
component 10 includes a pair of location tabs 11 which are
rectangular in shape.  The tabs are oriented parallel to each other
and perpendicular to mounting surface 12.  Each tab is oriented
perpendicular to a line between the centers of the tabs.  PCB 13
includes a pair of slots 14, which are similar in size, relative
location and orientation to tabs 11.  Pin-type component 15 i...