Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-05-09
2003-05-06
Martin, David (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S740000, C361S741000, C361S797000, C439S152000, C439S064000
Reexamination Certificate
active
06560120
ABSTRACT:
FIELD OF AND BACKGROUND OF THE INVENTION
The invention relates to modular systems that include a rack assembly for inserting electrical printed circuit boards. Such rack assemblies include at least opposite cross-connecting bars made of electrically conductive material, which are covered with guide bars situated opposite each other in pairs. Such rack assemblies thus provide volume elements suited for the insertion of electrical printed circuit boards. Such volume elements are also called mounting sites and are normally arranged parallel side by side. Electrical printed circuit boards can be inserted into such volume elements, which are then also arranged parallel side by side.
FIG. 1
shows one possible basic standard construction of a rack assembly
1
. The area for receiving printed circuit boards is bordered by cross-connecting bars made of electrically conductive material situated opposite each other. In the example shown in
FIG. 1
, there are two lower cross-connecting bars
5
,
7
and two opposite, upper cross-connecting bars
4
,
6
. The cross-connecting bars
4
,
5
form the boundaries of the front side of the rack assembly
1
, i.e., the insertion side
2
provided for positioning electrical printed circuit boards. The two cross-connecting bars
6
,
7
form the boundaries of the rear wall side
3
of the rack assembly
1
, which can be separated by a rear wall conductor plate. The cross-connecting bars
4
,
5
,
6
,
7
can be mounted by their ends, e.g., inside a control cabinet. In
FIG. 1
there are vertical side wall metal plates
8
,
9
, to which the cross-connecting bars are screwed at their ends. Lastly, the upper and lower sides of the rack assembly
1
are closed by an upper and a lower cover plate
10
,
11
.
So-called front elements are provided for closing the insertion side
2
of the rack assembly
1
. Such front elements are assigned to the individual mounting sites on the interior of the rack assembly, to whose width they are adjusted and to which they can be connected or disconnected. This possibility of closure can be independent of whether or not the mounting site located behind a front element contains an electrical printed circuit board. Thus, empty mounting sites can be covered with a front element placed on the insertion side
2
of the rack assembly
1
, in the manner of an empty site cover. Alternatively, electrical printed circuit boards can be provided with a front element on the front side, so that, after the printed circuit board has been inserted into the rack assembly
1
, the front element covers the corresponding mounting site on the insertion side
2
in the same manner.
In
FIG. 1
, front elements
12
,
13
are provided for the two mounting sites
56
,
57
on the left side of the rack assembly
1
. These front elements are multisectional in design. Thus, the front element
13
contains a vertical face plate
19
made of an electrically conductive material. The lower and upper front faces of the face plate
19
are provided with an end piece
20
,
21
, which usually also consists of an electrically conductive material. As an example, these end pieces can be provided with so-called rotary lever pulling handles
22
,
23
. Such handles can be operated by a person through a pivot action so that a front element
12
,
13
can be easily attached or taken off, or an electrical printed circuit board connected to a front element can be easily inserted or removed.
In the example shown in
FIG. 1
, the front element
12
has already been pushed on and completely covers the mounting site
56
located behind it, and lies in the plane of the insertion side
2
of the rack assembly
1
. In this example, the front element
13
of the mounting site
57
situated behind it is affixed to the printed circuit board
59
. This connection is advantageously achieved with the help of the two end pieces
20
,
21
. The printed circuit board has for the most part already been inserted into the mounting site
57
. After complete insertion into the mounting site
57
, the front element
13
will come to lie flush against the front element
12
in the plane of the insertion side
2
.
Guide bars for guiding the printed circuit boards are advantageously arranged in opposite pairs for each mounting site in the mounting zone between the cross-connecting bars. In the example shown in
FIG. 1
, the entire mounting zone between the upper and lower cross-connecting bars
4
,
6
and
5
,
7
, i.e., the sum of all mounting sites, is already provided with such pairs of guide bars. Thus, the printed circuit board
59
is guided on the upper and lower front side by the guide bars
14
,
15
situated opposite one another.
When inserting front elements or units made of front elements and electrical printed circuit boards, such elements should be centered in the insertion direction, particularly immediately before the final inserted position is achieved. This prevents an accidental lateral shift of, in particular, the front elements, which could at least hinder complete insertion thereof. This centering is especially necessary if adjoining mounting sites are already covered with front elements.
Finally, it is preferable to form a secure electrically conductive contact between the front elements and the rack assembly, particularly if the front elements and their components largely consist of electrically conductive materials. Electrically conductive contacts may be classified into the following different types.
One first type of contact can be described as a protective contact or ground contact. Through such a contact, high stray currents can be diverted from front elements to the rack assembly and then interrupted by downstream network protection devices, e.g., load separating switches or stray current line protection switches, at a speed ensuring the protection of persons. A protective contact should be especially effective if all the printed circuit boards in a rack assembly are electrically activated.
Another type of contact is used for diverting electrostatic voltage and can be described as an ESD (electro static discharge) contact. In this way, static potentials can be diverted from front elements to the rack assembly and its ground connection. An ESD contact should be especially effective when printed circuit boards are inserted into or removed from a rack assembly.
European patent 0 579 859 B1 describes a printed circuit board with guide pins for exact positioning during insertion into a rack assembly. In that patent, two guide pins are provided for centering a printed circuit board on the outsides of the corner assembly bodies. These guide pins support a longitudinal guide bar on the side flanks of the opposite head during insertion. In addition, a ground contact pin is arranged between the guide pins. This ground contact pin drops into an encoding chamber containing a ground contact spring on the front side of the opposite head of the longitudinal guide bar when the printed circuit board is inserted.
The reference WO 96/42187 describes a front system for a printed circuit board with an active/passive switch. For centering, the end piece of the printed circuit board is provided with a guide pin designed to enter into a corresponding guide bore. In that reference, no elements are provided for producing a protective electrical contact between the front element and the cross-connecting bars.
The reference WO 97/49271 describes a rack assembly for electrical printed circuit boards. The printed circuit boards are provided on one longitudinal side with a contact strip designed as a conductor track, which is interconnected to a metallic face plate of the printed circuit board via an electric resistor.
When the printed circuit board is inserted into the rack assembly, the contact strip comes into an electrically conductive contact loop with a contact spring, which is integrated in a guide bar, particularly at the head area, and is connected to the corresponding cross-connecting bars in an electrically conductive manner. The face plate of the printed circuit board is also provided wit
Kurrer Siegfried
Schaffer Kurt-Michael
Bui Hung
Martin David
Pauley Petersen Kinne & Erickson
Rittal Electronics Systems GmbH & Co. KG
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