Metal working – Plural diverse manufacturing apparatus
Reexamination Certificate
2001-02-09
2003-04-15
Martin, David (Department: 2841)
Metal working
Plural diverse manufacturing apparatus
C029S432000, C029S432100, C029SDIG003, C361S752000, C361S796000, C361S736000, C361S737000, C361S748000
Reexamination Certificate
active
06546615
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
Reference to a “Microfiche-Appendix”
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
In general the invention relates to fastening circuit boards to an electronic device. In particular the invention relates to a rack with board holders, which is used for fastening circuit boards by sliding them on place between board holders in a direction which is parallel with two edges of the circuit board. In addition, the invention relates to a device and a method for manufacturing board holders to a rack.
2. Description of the Related Art
Many modern electronic devices are mounted in a rack, whereby a typical prior art construction follows the principle shown in
FIG. 1. A
rack includes board holders fastened to horizontal shelves or vertical walls, between which the edges of the circuit board
100
are placed. In
FIG. 1
, the board holders are fastened to horizontal shelves, whereby there is a lower holder
101
a
for the lower edge of a board on the lower shelf, and an upper holder
101
b
for the upper edge on the upper shelf. There are connectors
102
on the board on the edge which goes in first when the board is pushed in place. The back wall of the rack is formed by the mother board
103
, on which there are counterparts
104
for the connectors. When the card is pushed in place, the connectors
102
meet the counterparts
104
, whereby the card is electrically connected to the mother board and through it to other boards of the same device. The number of boards in a certain device can be selected when the device is designed. Often the devices form families in which mother boards which are similar or nearly similar can be provided with a smaller number of boards for implementing a simple version, or with a larger number of boards for implementing a more versatile version.
Some prior art board holders will be briefly described in the following.
FIG. 1
shows separate board holders
101
a
and
101
b
made of metal or plastic, which are fastened to a shelf (or wall) generally by means of bungs or screws. They have the drawback that they are separate parts, and their number, dimensioning and other properties must be compatible with both the boards and the shelves, which causes a logistic problem in the assembly of the devices.
FIG. 2
shows board holders used in connection with shelves made of metal sheet, which are bent of the shelf metal. The board holder
201
comprises two tongues
201
a
and
201
b
reaching outward from the level of the shelf surface, which are formed by making a die cut shaped like a wide H, from which the rectangular areas that remain between the lines of the H are bent about 90 degrees around an imaginary axis which combines the ends of the vertical lines of the H. Many consecutive board holders like this can be formed to support the edge of one card. These board holders have the drawback of sharp edges, which can damage the card or injure the fingers of the person who assembles or services the device. The other type of board holder shown in
FIG. 2
consists of two elongated, raised pieces of metal sheet
202
a
and
202
b
, which are formed by making four parallel, straight cuts on the shelf metal. The area between two adjacent cuts is forced to an upraised position. These upraised strips are arranged in consecutive pairs, whereby the edge of the card is always placed between two adjacent strips. In this type of board holder the edges can also remain dangerously sharp. In addition, the board holders shown in
FIG. 2
have the drawback that both the upper and lower edge of the board do not always settle easily between the holders, but a part of the board may remain outside the holder, whereby the assembly of the device does not succeed.
An American registered design document number Des. 380,455 discloses a board holder according to
FIG. 3
, design protected by Metro Industries Inc., which is intended for use as the wall of a transport and storage shelf on which circuit boards are stored and/or transported during manufacture. The whole wall surface is covered by embossments
301
formed at regular distances, the shape and mutual placement of which is such that the board can be pushed on place either horizontally (arrow
302
), diagonally downwards (arrow
303
) or diagonally upwards (arrow
304
). A solution of the same type is known from the U.S. Pat. No. 4.382,517. This solution is shown in FIG.
4
. The surface of the wall panel comprises a number of diamond-shaped embossments
401
, which form diagonal grooving on the whole wall surface for the edged of the boards. In the board holders shown in
FIGS. 3 and 4
, both the problem of separate parts and sharp edges have been solved, but the solutions are not suitable as board holders of racks, because they would require either a diagonally placed mother board or counterparts for the board connectors fastened diagonally on the mother board, and these are not known in the prior art. If it were assumed by way of example that the solutions were suitable for racks, there would also be the problem that when the grooves are near each other, it is possible to push the card into the wrong groove by accident, and that would damage the connection between the board and the mother board. There will also be the problem of insufficient bending stiffness of a shelf with board holders, if the solution shown in
FIG. 3
or
4
were used on a shelf surface instead of a wall surface. Many boards with their components can be rather heavy, and if there are, for example, over 20 boards on a shelf which is 60 cm wide, their weight easily bends the lower shelf to an arched shape, whereby the upper edges of the boards in the middle may be detached from the upper holders. It would also be difficult to add ventilation holes to the board holders shown in the
FIGS. 3 and 4
to ensure sufficient circulation of cooling air.
It is an objective of the present invention to provide a rack with board holders which can be manufactured by simple methods, which is safe in use and in which it is difficult to install the boards incorrectly. It is also an objective of the invention that the board holder would contribute to making the rack more rigid. In addition, it is an objective of the invention that a rack made according to it can easily be scaled to provide different distances between boards. Furthermore, it is an objective of the invention that the rack can have both board holders and ventilation holes.
BRIEF SUMMARY OF THE INVENTION
The objectives of the invention are achieved by forming bubble-like embossments on the shelf or wall material, between which there are depressions for the edges of the board and which have two parallel edges in a direction which differs substantially from the direction intended as the direction of the edge of the board.
The rack according to the invention is characterized in that in order to support the first edge of the circuit boards, the first level surface of the rack comprises protruding embossments of the same material as the level surface, whereby the first embossment is between the point intended to support the first edge of the first circuit board and the point intended to support the first edge of the second circuit board, and that the extent of the embossment, perpendicular to the surface of the circuit boards, is the same as the distance between the circuit boards, and that the embossment has two parallel edges the direction of which differs substantially from the direction which is the intended direction of the first edge of the circuit boards.
The invention also relates to a device for manufacturing a board holder. The device according to the invention is characterized in that its working surface comprises a formation shaped like the letter H for forming two halves of an embossment delimited by the lines of the H on a level surface at one strike.
In addition, the invention relates to a method for manufacturing a board holder. The method accor
Hogan & Hartson LLP
Martin David
Tellabs Oy
Tran Thanh Y.
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