CA2258540A1 - Sub-rack for plug-in printed circuit modules with a means of damped discharge of electrostatic potential - Google Patents
Sub-rack for plug-in printed circuit modules with a means of damped discharge of electrostatic potential Download PDFInfo
- Publication number
- CA2258540A1 CA2258540A1 CA002258540A CA2258540A CA2258540A1 CA 2258540 A1 CA2258540 A1 CA 2258540A1 CA 002258540 A CA002258540 A CA 002258540A CA 2258540 A CA2258540 A CA 2258540A CA 2258540 A1 CA2258540 A1 CA 2258540A1
- Authority
- CA
- Canada
- Prior art keywords
- mounting rack
- bgt
- printed circuit
- contact
- circuit board
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
- H05F3/00—Carrying-off electrostatic charges
- H05F3/02—Carrying-off electrostatic charges by means of earthing connections
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/648—Protective earth or shield arrangements on coupling devices, e.g. anti-static shielding
- H01R13/6485—Electrostatic discharge protection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02B—BOARDS, SUBSTATIONS OR SWITCHING ARRANGEMENTS FOR THE SUPPLY OR DISTRIBUTION OF ELECTRIC POWER
- H02B1/00—Frameworks, boards, panels, desks, casings; Details of substations or switching arrangements
- H02B1/16—Earthing arrangements
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
- H05F3/00—Carrying-off electrostatic charges
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
- H05K7/1417—Mounting supporting structure in casing or on frame or rack having securing means for mounting boards, plates or wiring boards
- H05K7/1418—Card guides, e.g. grooves
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0067—Devices for protecting against damage from electrostatic discharge
Abstract
The invention is a sub-rack (BGT) for a plug-in printed circuit modules (BG) with a resistor (R) located between the front panel (FP) and a sliding contact (K). Damped discharge of electrostatic charges on the front plate (FP) to the sub-rack (BGT) is accomplished through the resistor (R). The advantage of the sub-rack (BGT) as per the invention is that printed circuit modules (BG) may be plugged in or detached during operation of the other printed circuit modules in the sub-rack (BGT) without the emission of interfering signals which could impair the correct function of the remaining printed circuit modules.
Description
~ s ~
CA 022~8~40 l998-l2-l6 .; -.
~L~ E13SAM~NDE~
Description ~ i,'A~LATE~N
Mounting rack for plug-in electrical printed circuit board assemblies having means for damped dissipation of electrostatic potentials.
A problem which can occur when inserting an electrical printed circuit board assembly into a mounting rack is that external electrostatic voltages and static voltage potentials can cause interference in the interior of the mounting rack and, in this case, in particular in the case of other printed circuit board assemblies which have already been inserted. In this case, during the insertion process, an electrostatic voltage is transferred, in particular from a person, first of all to an electrically conductive, in particular metallic front panel of the printed circuit board assembly to be inserted. As a rule, the electrostatic voltages are very high and, as a result of discharge processes, for example as a result of radio-frequency signals produced by a spark gap or as a result of a rise in potential, can cause interference with electrical components on the printed circuit board assembly itself, or on adjacent printed circuit board assemblies. This is particularly undesirable if it is intended to be possible to insert and withdraw printed circuit board assemblies during operation of other printed circuit board assemblies in the mounting rack.
The insertion and withdrawal of a printed circuit board assembly during operation of the other printed circuit board assemblies is called "live insertionn.
Figure la shows a detail of a side section through the lower region of one known configuration of a mounting rack BGT. In this case, a detail is once again illustrated, by way of example, of an electrical printed circuit board assembly BG. This has at least one printed circuit board LP, to the front face of which an electrically conductive, in particular metallic, front panel FP is fitted, and to the rear face of which a plug connector V2 is fitted.
- wo 97/49271 - la - PCT/DE97/01234 Furthermore, there is a strip sliding contact K which extends along the lower edge region of the printed CA 022~8~40 1998-12-16 ., .
CA 022~8~40 l998-l2-l6 .; -.
~L~ E13SAM~NDE~
Description ~ i,'A~LATE~N
Mounting rack for plug-in electrical printed circuit board assemblies having means for damped dissipation of electrostatic potentials.
A problem which can occur when inserting an electrical printed circuit board assembly into a mounting rack is that external electrostatic voltages and static voltage potentials can cause interference in the interior of the mounting rack and, in this case, in particular in the case of other printed circuit board assemblies which have already been inserted. In this case, during the insertion process, an electrostatic voltage is transferred, in particular from a person, first of all to an electrically conductive, in particular metallic front panel of the printed circuit board assembly to be inserted. As a rule, the electrostatic voltages are very high and, as a result of discharge processes, for example as a result of radio-frequency signals produced by a spark gap or as a result of a rise in potential, can cause interference with electrical components on the printed circuit board assembly itself, or on adjacent printed circuit board assemblies. This is particularly undesirable if it is intended to be possible to insert and withdraw printed circuit board assemblies during operation of other printed circuit board assemblies in the mounting rack.
The insertion and withdrawal of a printed circuit board assembly during operation of the other printed circuit board assemblies is called "live insertionn.
Figure la shows a detail of a side section through the lower region of one known configuration of a mounting rack BGT. In this case, a detail is once again illustrated, by way of example, of an electrical printed circuit board assembly BG. This has at least one printed circuit board LP, to the front face of which an electrically conductive, in particular metallic, front panel FP is fitted, and to the rear face of which a plug connector V2 is fitted.
- wo 97/49271 - la - PCT/DE97/01234 Furthermore, there is a strip sliding contact K which extends along the lower edge region of the printed CA 022~8~40 1998-12-16 ., .
circuit board LP. This sliding contact K is electrically conductively connected to the front panel FP of the printed circuit board assembly BG. At least one lower guide rail LS is provided on the mounting rack BGT for insertion of the printed circuit board assembly BG in the insertion direction ER, and is fitted between a front and a rear transverse rail QV, QH. At least one contact spring element F1 is arranged in the front region in the interior of the mounting rack BGT and is electrically conductively connected to it, preferably via the front transverse rail QV located underneath. The contact spring element is advantageously integrated in the guide rail. One possible embodiment for such integration can be found in German Patent Specification DE 3 24 883 C2. When the printed circuit board assembly BG is being inserted, the contact spring element F1 makes contact with the sliding contact K at the start of the insertion process, so that an electrically conductive connection is produced between the front panel FP and the mounting rack BGT, which is normally at zero voltage potential.
It is disadvantageous that possible external electrostatic voltages stored on the front panel FP can produce a spark gap in the interior of the mounting rack BGT when contact is made between the sliding contact K and the contact spring element F1 during insertion of the printed circuit board assembly BG into the mounting rack BGT. Such a spark gap produces radio-frequency interference signals which, for example, can interfere with the operation o~ adjacent printed circuit board assemblies which have already been inserted into the mounting rack BGT.
Figure lb shows the mounting rack BGT, which has already been illustrated in Figure la, with the printed circuit board assembly BG in the inserted state. The plug connector V2 on the rear face of the printed circuit board assembly BG is now inserted into a corresponding plug connector V1 such that contact is made, which plug connector V1 is preferably fitted on a CA 02258540 l998-l2-l6 ., ~
- WO 97/49271 - 2a - PCT/DE97/01234 so-called mother board CA 022~8~40 1998-12-16 , . .
in the interior of the mounting rack. Potentials which are applied to the front panel FP from the outside, for example an electrostatic voltage applied by touching, flow via the sliding contact K, the contact spring element F1 and the transverse rail QV to the mounting rack BGT, which is normally grounded. A problem is caused by interference which in this case can possibly be "emitted" via the "antenna-liken strip sliding contact K deeply into the interior of the mounting rack lO BGT, and can thus likewise interfere with the operation of printed circuit board assemblies in the mounting rack BGT.
Finally, as a rule, at least one contact screw SR is fitted at the lower end of the front panel FP.
Once the printed circuit board assembly BG has been completely inserted, this contact screw SR is screwed, for example, to the lower transverse rail QV and then acts as a protective contact, which has an adequate current carrying capacity.
The object of the invention is to dissipate electrostatic charges on printed circuit board assemblies to the mounting rack in such a manner that interference-free operation is ensured of other printed circuit board assemblies which have already been inserted into the mounting rack and are in operation.
The object is achieved by the mounting rack specified in claim 1. Other, advantageous embodiments are contained in the dependent claims.
An advantage of the mounting rack according to the invention is that electrostatic charges which are applied to the front panel can be dissipated to the mounting rack, damped by an electrical resistor, not in the manner of a short circuit and with a definable time constant. As in the case of a resistor/capacitor circuit, electrical charges are dissipated from the front panel of the printed circuit board assembly, which acts as a capacitor, damped via the resistor. The CA 022~8~40 l998-l2-l6 invention thus prevents sparks from being formed between the sliding contact and the contact spring element while the printed circuit board assembly is - being inserted into the mounting rack. In consequence, there is advantageously no need to be concerned about interference signals caused by flashovers in the mounting rack.
Further spring elements which may also be present in the interior of the mounting rack represent a further advantage in one embodiment. As a result of this, according to the invention, a sliding contact on the printed circuit board assembly can also make contact with the mounting rack in the rear region of the latter. The possible "antenna effect" of the sliding contact is thus also prevented if interference is applied from the outside to the front panel when the printed circuit board assembly is in the inserted state.
Further advantageous embodiments of the invention are specified in the corresponding dependent claims.
The invention will be described in more detail below with reference to an exemplary embodiment that is illustrated in the figures, which are described briefly below and in which:
FIG la shows, by way of example, a side view of the already explained embodiment of a known mounting rack, FIG lb shows, by way of example, the side view of the already explained, known mounting rack illustrated in Figure la, with a printed circuit board assembly completely inserted, FIG 2a shows the side view of an exemplary embodiment of a mounting rack according to the invention, having a resistor between the sliding contact and the front panel of a printed circuit board assembly, CA 022~8~40 1998-12-16 . . .
~ WO 97/49271 - 5 - PCT/DE97/01234 FIG 2b shows the side view of the mounting rack shown in Figure 2a, with a printed circuit board assembly completely inserted, FIB 3a shows the side view of a further embodiment of the mounting rack according to the invention, with an additional contact pin on the inside of the front panel, and FIG 3b shows the side view of the mounting rack shown in Figure 3a, with a printed circuit board assembly completely inserted.
By way of example, Figure 2a shows a side view of a mounting rack BGT according to the invention, with an electrical printed circuit board assembly BG which can be pushed into it. This printed circuit board assembly BG has an electrically conductive, preferably metallic, front panel FP and a printed circuit board LP. At least one lower guide rail LS is advantageously fitted in the mounting rack BGT in order to allow the printed circuit board assembly BG to be inserted into it, and is used to hold and guide the printed circuit board LP over its edge. An electromagnetically shielding front face of the mounting rack BGT is formed in particular by means of the respective front panels FP of a plurality of printed circuit board assemblies BG which can be inserted into the mounting rack BGT
alongside one another. On the edge regions, the printed circuit board LP has at least one strip sliding contact K with which an electrically conductive contact is made, during insertion of the printed circuit board assembly BG, by a means Fl for making electrical contact between the sliding contact K and the mounting rack BGT.
According to the invention, the sliding contact K of the printed circuit board assembly BG is not directly electrically connected to the front panel FP.
Instead of this, there is an isolation gap G between the front panel FP and the sliding contact K, which gap CA 022~8~40 1998-12-16 .. ..
is bridged by an electrical resistor R which can be selected. For example, electrostatic charges applied by a person making touching contact with the front panel FP are thus dissipated, during insertion of the printed circuit board assembly BG, virtually without causing any interference signals at all, by means of a discharge (which is damped via the resistor) to the mounting rack BGT, which is normally at ground potential. The resistor is advantageously connected to an electrically conductive end piece ES, which is used to attach the front panel FP to the printed circuit board LP.
The discharge process in the mounting rack BGT
during insertion of the printed circuit board assembly BG takes place via the resistor R, the contact strip K
and the means F1 for making electrical contact with the sliding contact K. This has, in particular, a contact spring element F1 for making electrical contact with the sliding contact K and can, for example, be fitted in the region of the guide rail LS, and/or can be integrated in it. As soon as the process of inserting the printed circuit board assembly BG into the mounting rack BGT starts, the sliding contact K, which is in general mounted on the printed circuit board LP in the form of a conductor track, is gripped in a sprung manner, and made contact with, by the contact spring element F1.
According to a further embodiment of the mounting rack BGT according to the invention, this mounting rack BGT has at least one ~urther means F2 for making electrical contact between the sliding contact K
and the mounting rack BGT. The means F2 preferably has a contact spring element F2 for making electrical contact with the slidlng contact K, which is electrically conductively connected to the mounting rack BGT, preferably in the region of the guide rail LS
in the rear region in the interior of the mounting rack BGT, and corresponds to the contact spring element F1.
Thus, according to the invention, when the printed CA 02258540 l998-l2-l6 - WO 97/49271 - 6a - PCT/DE97/01234 circuit board assembly BG is being inserted into the mounting rack BGT, there is also an electrically CA 022~8~40 1998-12-16 . . .
conductive connection for the strip sliding contact K
in the rear region of the interior of the mounting rack BGT. The term rear region in this context means that region of the mounting rack BGT which faces away from the front panel FP when the printed circuit board assembly BG is inserted.
The additional contact, according to the invention, of the sliding contact K in the rear region of the mounting rack BGT has, in particular, the advantage that, when the printed circuit board assembly BG is in the inserted state as is illustrated in Figure lb, electrostatic charges applied from the outside to the front panel, in particular, cannot penetrate deeply into the mounting rack BGT via the strip sliding contact K. Since the sliding contact K makes contact with the mounting rack BGT at least on both sides by means of the contact spring elements F1 and F2, there are advantageously no long exposed "antenna-liken regions of the strip sliding contact K. Thus, according to the invention, possible radio-frequency "emissions"
of interference signals via the sliding contact K are prevented. The contact spring elements Fl and F2 can be electrically conductively connected to the mounting rack BGT in particular by means of a connection to a ~ront and a rear transverse rail QV and QH, respectively, of the mounting rack BGT.
In a further embodiment of the mounting rack BGT according to the invention, means are additionally provided for making electrically conductive contact between the front panel FP and the mounting rack BGT.
These means are represented by the reference symbol SR
in the figures, and are preferably in the form of a screw. These means come into play when the front panel FP is in the inserted state.
Figure 2b shows the mounting rack BGT already illustrated in Figure 2a, with an inserted printed circuit board assembly BG and with at least one screw SR passing through the front panel FP as the means ~or producing the electrically conductive contact between - WO 97/49271 - 7a - PCT/DE97/01234 the ~ront panel FP and the mounting rack BGT. At least CA 022~8~40 1998-12-16 - WO 97/49271 - 8a - PCT/DE97/01234 one screw SR in each case preferably passes through the front panel FP at opposite ends (not illustrated), by means of which the printed circuit board assembly BG is screwed to the mounting rack BGT, in particular to a front transverse rail QV, in the inserted state, such that electrical contact is made. Thus, according to the invention, a further contact is made between the metallic front panel FP and the mounting rack BGT. In the completely inserted state, this advantageously results in the capability to discharge electrostatic charges applied from the outside to the front panel FP, via the screw SR, directly to the mounting rack BGT, so that such charges do not reach the interior of the mounting rack BGT via the contact strip K. Such a contact means SR, which is preferably like a screw, bridges the series circuits formed by the resistor R, the sliding contact K and the electrical contact means Fl, F2 to the mounting rack BGT.
Figure 3a shows a further embodiment of the mounting rack BGT according to the invention, in which case the front panel FP has at least one additional contact pin KS. This is preferably fitted at the lower end of the front panel and points into the interior of the mounting rack, in the insertion direction ER of the printed circuit board assembly. During the process of inserting the printed circuit board assembly BG, the contact pin KS on the front panel FP makes direct electrically conductive contact with the mounting rack BGT, via a further contact spring element F4. The contact spring element F4 is preferably conductively connected to the lower transverse rail QV.
Such an embodiment according to the invention is particularly advantageous in the case of printed circuit board assemblies BG which cannot be screwed to the mounting rack BGT but, for example, can be latched to the mounting rack BGT by means of a so-called lever pulling handle H. In such a case, both the contact pin KS and the contact spring element F4 are designed to be suf~iciently mechanically robust that a plurality of CA 022~8~40 1998-12-16 ~ , , .
~unctions can be carried out at the same time. On the one hand, the contact pin and contact spring can act as a mechanical guide ~or the printed circuit board assembly during the insertion process, so that it is possible to prevent the printed circuit board assembly ~rom being displaced laterally. Furthermore, when the printed circuit board assembly is in the completely inserted state, the two elements can be used as a so-called protective contact. This facilitates a ground connection ~or the ~ront panel, in accordance with the VDE requirements. It is then possible to dispense with an additional screw SR, as is illustrated according to the prior art in Figures la and lb. Finally, the two elements can also produce a mechanical joint between the printed circuit board assembly and the mounting rack such that there is no longer any need ~or an additional screw ~or ~urther ~ixing.
The contact spring element F4 is in this case preferably ~itted in the ~ront region o~ the mounting rack BGT, in the region o~ the guide rail LS, and is electrically conductively connected to the mounting rack BGT. The contact spring element F4 may be electrically conductively connected to, for example, a front transverse rail QV o~ the mounting rack BGT.
When the printed circuit board assembly BG is being inserted, the contact pin KS makes electrically conductive contact with the contact spring element F4 be~ore the connection is made between the plug connector V1 of the mounting rack BGT and the plug connector V2 o~ the printed circuit board LP of the printed circuit board assembly BG. Thus, in addition to the sliding contact, there is a ~urther option ~or advantageously discharging electrostatic charges located on the ~ront panel FP via the contact pin KS
and the contact spring element F4 to the mounting rack BGT be~ore the assembly BG is brought into use by the mating o~ the plug connectors V1 and V2.
Figure 3b shows the mounting rack BGT already illustrated in Figure 3a, with an inserted printed ~, .
- WO 97/49271 - 9a - PCT/DE97/01234 circuit board assembly BG. According to the invention, when the printed CA 022~8~40 l998-l2-l6 WO 97/49271 - lO - PCT/DE97/01234 circuit board assembly BG is in the inserted state, electrostatic charges applied in particular from the outside to the front panel FP can advantageously be discharged via the contact pin KS and the contact spring element F4 directly to the mounting rack BGT, and do not pass via the contact strip K into the interior of said mounting rack BGT.
An advantage of a mounting rack according to the invention is, in particular, the capability to insert and withdraw a printed circuit board assembly BG
even during operation of the other, further printed circuit board assemblies in the mounting rack without this causing any emission of interference signals which could adversely affect the correct operation of the other printed circuit board assemblies in the mounting rack BGT.
It is disadvantageous that possible external electrostatic voltages stored on the front panel FP can produce a spark gap in the interior of the mounting rack BGT when contact is made between the sliding contact K and the contact spring element F1 during insertion of the printed circuit board assembly BG into the mounting rack BGT. Such a spark gap produces radio-frequency interference signals which, for example, can interfere with the operation o~ adjacent printed circuit board assemblies which have already been inserted into the mounting rack BGT.
Figure lb shows the mounting rack BGT, which has already been illustrated in Figure la, with the printed circuit board assembly BG in the inserted state. The plug connector V2 on the rear face of the printed circuit board assembly BG is now inserted into a corresponding plug connector V1 such that contact is made, which plug connector V1 is preferably fitted on a CA 02258540 l998-l2-l6 ., ~
- WO 97/49271 - 2a - PCT/DE97/01234 so-called mother board CA 022~8~40 1998-12-16 , . .
in the interior of the mounting rack. Potentials which are applied to the front panel FP from the outside, for example an electrostatic voltage applied by touching, flow via the sliding contact K, the contact spring element F1 and the transverse rail QV to the mounting rack BGT, which is normally grounded. A problem is caused by interference which in this case can possibly be "emitted" via the "antenna-liken strip sliding contact K deeply into the interior of the mounting rack lO BGT, and can thus likewise interfere with the operation of printed circuit board assemblies in the mounting rack BGT.
Finally, as a rule, at least one contact screw SR is fitted at the lower end of the front panel FP.
Once the printed circuit board assembly BG has been completely inserted, this contact screw SR is screwed, for example, to the lower transverse rail QV and then acts as a protective contact, which has an adequate current carrying capacity.
The object of the invention is to dissipate electrostatic charges on printed circuit board assemblies to the mounting rack in such a manner that interference-free operation is ensured of other printed circuit board assemblies which have already been inserted into the mounting rack and are in operation.
The object is achieved by the mounting rack specified in claim 1. Other, advantageous embodiments are contained in the dependent claims.
An advantage of the mounting rack according to the invention is that electrostatic charges which are applied to the front panel can be dissipated to the mounting rack, damped by an electrical resistor, not in the manner of a short circuit and with a definable time constant. As in the case of a resistor/capacitor circuit, electrical charges are dissipated from the front panel of the printed circuit board assembly, which acts as a capacitor, damped via the resistor. The CA 022~8~40 l998-l2-l6 invention thus prevents sparks from being formed between the sliding contact and the contact spring element while the printed circuit board assembly is - being inserted into the mounting rack. In consequence, there is advantageously no need to be concerned about interference signals caused by flashovers in the mounting rack.
Further spring elements which may also be present in the interior of the mounting rack represent a further advantage in one embodiment. As a result of this, according to the invention, a sliding contact on the printed circuit board assembly can also make contact with the mounting rack in the rear region of the latter. The possible "antenna effect" of the sliding contact is thus also prevented if interference is applied from the outside to the front panel when the printed circuit board assembly is in the inserted state.
Further advantageous embodiments of the invention are specified in the corresponding dependent claims.
The invention will be described in more detail below with reference to an exemplary embodiment that is illustrated in the figures, which are described briefly below and in which:
FIG la shows, by way of example, a side view of the already explained embodiment of a known mounting rack, FIG lb shows, by way of example, the side view of the already explained, known mounting rack illustrated in Figure la, with a printed circuit board assembly completely inserted, FIG 2a shows the side view of an exemplary embodiment of a mounting rack according to the invention, having a resistor between the sliding contact and the front panel of a printed circuit board assembly, CA 022~8~40 1998-12-16 . . .
~ WO 97/49271 - 5 - PCT/DE97/01234 FIG 2b shows the side view of the mounting rack shown in Figure 2a, with a printed circuit board assembly completely inserted, FIB 3a shows the side view of a further embodiment of the mounting rack according to the invention, with an additional contact pin on the inside of the front panel, and FIG 3b shows the side view of the mounting rack shown in Figure 3a, with a printed circuit board assembly completely inserted.
By way of example, Figure 2a shows a side view of a mounting rack BGT according to the invention, with an electrical printed circuit board assembly BG which can be pushed into it. This printed circuit board assembly BG has an electrically conductive, preferably metallic, front panel FP and a printed circuit board LP. At least one lower guide rail LS is advantageously fitted in the mounting rack BGT in order to allow the printed circuit board assembly BG to be inserted into it, and is used to hold and guide the printed circuit board LP over its edge. An electromagnetically shielding front face of the mounting rack BGT is formed in particular by means of the respective front panels FP of a plurality of printed circuit board assemblies BG which can be inserted into the mounting rack BGT
alongside one another. On the edge regions, the printed circuit board LP has at least one strip sliding contact K with which an electrically conductive contact is made, during insertion of the printed circuit board assembly BG, by a means Fl for making electrical contact between the sliding contact K and the mounting rack BGT.
According to the invention, the sliding contact K of the printed circuit board assembly BG is not directly electrically connected to the front panel FP.
Instead of this, there is an isolation gap G between the front panel FP and the sliding contact K, which gap CA 022~8~40 1998-12-16 .. ..
is bridged by an electrical resistor R which can be selected. For example, electrostatic charges applied by a person making touching contact with the front panel FP are thus dissipated, during insertion of the printed circuit board assembly BG, virtually without causing any interference signals at all, by means of a discharge (which is damped via the resistor) to the mounting rack BGT, which is normally at ground potential. The resistor is advantageously connected to an electrically conductive end piece ES, which is used to attach the front panel FP to the printed circuit board LP.
The discharge process in the mounting rack BGT
during insertion of the printed circuit board assembly BG takes place via the resistor R, the contact strip K
and the means F1 for making electrical contact with the sliding contact K. This has, in particular, a contact spring element F1 for making electrical contact with the sliding contact K and can, for example, be fitted in the region of the guide rail LS, and/or can be integrated in it. As soon as the process of inserting the printed circuit board assembly BG into the mounting rack BGT starts, the sliding contact K, which is in general mounted on the printed circuit board LP in the form of a conductor track, is gripped in a sprung manner, and made contact with, by the contact spring element F1.
According to a further embodiment of the mounting rack BGT according to the invention, this mounting rack BGT has at least one ~urther means F2 for making electrical contact between the sliding contact K
and the mounting rack BGT. The means F2 preferably has a contact spring element F2 for making electrical contact with the slidlng contact K, which is electrically conductively connected to the mounting rack BGT, preferably in the region of the guide rail LS
in the rear region in the interior of the mounting rack BGT, and corresponds to the contact spring element F1.
Thus, according to the invention, when the printed CA 02258540 l998-l2-l6 - WO 97/49271 - 6a - PCT/DE97/01234 circuit board assembly BG is being inserted into the mounting rack BGT, there is also an electrically CA 022~8~40 1998-12-16 . . .
conductive connection for the strip sliding contact K
in the rear region of the interior of the mounting rack BGT. The term rear region in this context means that region of the mounting rack BGT which faces away from the front panel FP when the printed circuit board assembly BG is inserted.
The additional contact, according to the invention, of the sliding contact K in the rear region of the mounting rack BGT has, in particular, the advantage that, when the printed circuit board assembly BG is in the inserted state as is illustrated in Figure lb, electrostatic charges applied from the outside to the front panel, in particular, cannot penetrate deeply into the mounting rack BGT via the strip sliding contact K. Since the sliding contact K makes contact with the mounting rack BGT at least on both sides by means of the contact spring elements F1 and F2, there are advantageously no long exposed "antenna-liken regions of the strip sliding contact K. Thus, according to the invention, possible radio-frequency "emissions"
of interference signals via the sliding contact K are prevented. The contact spring elements Fl and F2 can be electrically conductively connected to the mounting rack BGT in particular by means of a connection to a ~ront and a rear transverse rail QV and QH, respectively, of the mounting rack BGT.
In a further embodiment of the mounting rack BGT according to the invention, means are additionally provided for making electrically conductive contact between the front panel FP and the mounting rack BGT.
These means are represented by the reference symbol SR
in the figures, and are preferably in the form of a screw. These means come into play when the front panel FP is in the inserted state.
Figure 2b shows the mounting rack BGT already illustrated in Figure 2a, with an inserted printed circuit board assembly BG and with at least one screw SR passing through the front panel FP as the means ~or producing the electrically conductive contact between - WO 97/49271 - 7a - PCT/DE97/01234 the ~ront panel FP and the mounting rack BGT. At least CA 022~8~40 1998-12-16 - WO 97/49271 - 8a - PCT/DE97/01234 one screw SR in each case preferably passes through the front panel FP at opposite ends (not illustrated), by means of which the printed circuit board assembly BG is screwed to the mounting rack BGT, in particular to a front transverse rail QV, in the inserted state, such that electrical contact is made. Thus, according to the invention, a further contact is made between the metallic front panel FP and the mounting rack BGT. In the completely inserted state, this advantageously results in the capability to discharge electrostatic charges applied from the outside to the front panel FP, via the screw SR, directly to the mounting rack BGT, so that such charges do not reach the interior of the mounting rack BGT via the contact strip K. Such a contact means SR, which is preferably like a screw, bridges the series circuits formed by the resistor R, the sliding contact K and the electrical contact means Fl, F2 to the mounting rack BGT.
Figure 3a shows a further embodiment of the mounting rack BGT according to the invention, in which case the front panel FP has at least one additional contact pin KS. This is preferably fitted at the lower end of the front panel and points into the interior of the mounting rack, in the insertion direction ER of the printed circuit board assembly. During the process of inserting the printed circuit board assembly BG, the contact pin KS on the front panel FP makes direct electrically conductive contact with the mounting rack BGT, via a further contact spring element F4. The contact spring element F4 is preferably conductively connected to the lower transverse rail QV.
Such an embodiment according to the invention is particularly advantageous in the case of printed circuit board assemblies BG which cannot be screwed to the mounting rack BGT but, for example, can be latched to the mounting rack BGT by means of a so-called lever pulling handle H. In such a case, both the contact pin KS and the contact spring element F4 are designed to be suf~iciently mechanically robust that a plurality of CA 022~8~40 1998-12-16 ~ , , .
~unctions can be carried out at the same time. On the one hand, the contact pin and contact spring can act as a mechanical guide ~or the printed circuit board assembly during the insertion process, so that it is possible to prevent the printed circuit board assembly ~rom being displaced laterally. Furthermore, when the printed circuit board assembly is in the completely inserted state, the two elements can be used as a so-called protective contact. This facilitates a ground connection ~or the ~ront panel, in accordance with the VDE requirements. It is then possible to dispense with an additional screw SR, as is illustrated according to the prior art in Figures la and lb. Finally, the two elements can also produce a mechanical joint between the printed circuit board assembly and the mounting rack such that there is no longer any need ~or an additional screw ~or ~urther ~ixing.
The contact spring element F4 is in this case preferably ~itted in the ~ront region o~ the mounting rack BGT, in the region o~ the guide rail LS, and is electrically conductively connected to the mounting rack BGT. The contact spring element F4 may be electrically conductively connected to, for example, a front transverse rail QV o~ the mounting rack BGT.
When the printed circuit board assembly BG is being inserted, the contact pin KS makes electrically conductive contact with the contact spring element F4 be~ore the connection is made between the plug connector V1 of the mounting rack BGT and the plug connector V2 o~ the printed circuit board LP of the printed circuit board assembly BG. Thus, in addition to the sliding contact, there is a ~urther option ~or advantageously discharging electrostatic charges located on the ~ront panel FP via the contact pin KS
and the contact spring element F4 to the mounting rack BGT be~ore the assembly BG is brought into use by the mating o~ the plug connectors V1 and V2.
Figure 3b shows the mounting rack BGT already illustrated in Figure 3a, with an inserted printed ~, .
- WO 97/49271 - 9a - PCT/DE97/01234 circuit board assembly BG. According to the invention, when the printed CA 022~8~40 l998-l2-l6 WO 97/49271 - lO - PCT/DE97/01234 circuit board assembly BG is in the inserted state, electrostatic charges applied in particular from the outside to the front panel FP can advantageously be discharged via the contact pin KS and the contact spring element F4 directly to the mounting rack BGT, and do not pass via the contact strip K into the interior of said mounting rack BGT.
An advantage of a mounting rack according to the invention is, in particular, the capability to insert and withdraw a printed circuit board assembly BG
even during operation of the other, further printed circuit board assemblies in the mounting rack without this causing any emission of interference signals which could adversely affect the correct operation of the other printed circuit board assemblies in the mounting rack BGT.
Claims (6)
1. A mounting rack (BGT), having a) at least one electrical printed circuit board assembly (BG) which can be plugged into this mounting rack (BGT), and has a metallic front panel (FP) and a printed circuit board (LP) having at least one strip sliding contact (K) in the edge regions, and having b) contact means (F1, F2) for making electrical contact between the strip sliding contact (K) of the printed circuit board assembly (BG) and the mounting rack (BGT), at least one such contact means (F1) being arranged in the front region in the interior of the mounting rack (BGT), distinguished by c) an electrical resistor (R) which electrically conductively connects the front panel (FP) of the electrical printed circuit board assembly (BG) to the sliding contact (K).
2. The mounting rack (BGT) as claimed in claim 1, characterized in that the contact means (F1, F2) have at least one contact spring element (F1) in order to make electrical contact with the sliding contact (K).
3. The mounting rack (BGT) as claimed in claim 2, characterized in that the mounting rack (BGT) has at least one guide rail (LS) in order to hold the electrical printed circuit board assemblies (BG), and the at least one contact spring element (F1) is integrated in a guide rail (LS).
4. The mounting rack (BGT) as claimed in one of the preceding claims, characterized in that at least one further contact means (F2) for making electrical contact with the sliding contact (K) is arranged in the rear region in the interior of the mounting rack (BGT).
5. The mounting rack (BGT) as claimed in one of the preceding claims, having at least one screw (SR) for electrically conductive screw connection of the front panel (FP) to the mounting rack (BGT) in the completely inserted state.
6. The mounting rack (BGT) as claimed in claim 1, distinguished by at least one contact pin (KS) which is electrically conductively fitted on the front panel (FP) and makes electrically conductive contact with a contact spring element (F4) during insertion of the printed circuit board assembly (BG) into the mounting rack (BGT).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE29610694U DE29610694U1 (en) | 1996-06-18 | 1996-06-18 | Subrack with means for discharging electrostatic voltages in pluggable modules |
| DE29610694.1 | 1996-06-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2258540A1 true CA2258540A1 (en) | 1997-12-24 |
Family
ID=8025360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002258540A Abandoned CA2258540A1 (en) | 1996-06-18 | 1997-06-17 | Sub-rack for plug-in printed circuit modules with a means of damped discharge of electrostatic potential |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0906718B1 (en) |
| JP (1) | JP3630240B2 (en) |
| KR (1) | KR20000016737A (en) |
| CN (1) | CN1111342C (en) |
| AT (1) | ATE196969T1 (en) |
| CA (1) | CA2258540A1 (en) |
| CZ (1) | CZ288037B6 (en) |
| DE (3) | DE29610694U1 (en) |
| ES (1) | ES2151735T3 (en) |
| HU (1) | HUP9903790A3 (en) |
| SK (1) | SK174398A3 (en) |
| WO (1) | WO1997049271A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4263851B2 (en) | 1998-11-09 | 2009-05-13 | リッタル エレクトロニク システムズ ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニ コマンディート ゲゼルシャフト | Modular system for printed circuit boards with front element centering contact parts and independent receiving contact parts, in particular contact pieces, in the rack assembly |
| DE10052628C2 (en) * | 2000-10-24 | 2002-09-12 | Abb Patent Gmbh | Electrostatic charge dissipation system |
| CN103857247A (en) * | 2012-12-05 | 2014-06-11 | 深圳市共进电子股份有限公司 | Anti-electrostatic interference cabinet veneer |
| JP6177647B2 (en) * | 2013-10-02 | 2017-08-09 | ＡＰＲＥＳＩＡ Ｓｙｓｔｅｍｓ株式会社 | Electronic equipment and shield structure thereof |
| JP6565176B2 (en) * | 2014-11-27 | 2019-08-28 | 富士通株式会社 | Electronic device and mounting method |
| CN108163121A (en) * | 2017-11-14 | 2018-06-15 | 天津市爱轮德自行车有限公司 | A kind of built-in lithium ion battery power-assisted electric vehicle with wireless blue tooth communication system |
| CN108418122A (en) * | 2018-05-05 | 2018-08-17 | 中科天工电气控股有限公司 | One kind destaticing distribution box |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1268238B (en) * | 1964-09-30 | 1968-05-16 | Siemens Ag | Arrangement with four-pole adjustable in steps |
| US3488628A (en) * | 1967-09-27 | 1970-01-06 | Amp Inc | Electrical interconnecting system and parts |
| US3479634A (en) * | 1967-10-25 | 1969-11-18 | Amp Inc | Printed circuit board connectors |
| DE2743194C2 (en) * | 1977-09-26 | 1985-04-25 | Hartmann & Braun Ag, 6000 Frankfurt | Arrangement for connecting circuit boards in subracks to a potential equalization line |
| FR2498380A1 (en) * | 1981-01-16 | 1982-07-23 | Alsthom Cgee | CONNECTOR FOR DRAWER ELECTRICAL EQUIPMENT |
| DE3624883A1 (en) * | 1986-07-23 | 1988-01-28 | Siemens Ag | Contact spring |
| GB2222726A (en) * | 1988-09-08 | 1990-03-14 | Racal Milgo Ltd | Printed circuit boards |
| US4864458A (en) * | 1988-12-08 | 1989-09-05 | Ibm Corporation | Electrostatic discharge grounding switch and method of operating same |
| JPH0617356Y2 (en) * | 1989-05-16 | 1994-05-02 | ホシデン株式会社 | Antistatic connector |
| DE4110800C1 (en) * | 1991-04-04 | 1992-07-23 | Schroff Gmbh, 7541 Straubenhardt, De | |
| DE9114287U1 (en) * | 1991-11-16 | 1993-03-18 | Robert Bosch Gmbh, 7000 Stuttgart, De | |
| DE9301528U1 (en) * | 1993-02-04 | 1993-04-08 | Philips Patentverwaltung Gmbh, 2000 Hamburg, De | |
| SE502734C2 (en) * | 1993-10-12 | 1995-12-18 | Ellemtel Utvecklings Ab | Device at a magazine |
| DE29503735U1 (en) * | 1995-03-06 | 1995-06-22 | Sihn Jr Kg Wilhelm | Shielded housing for high-frequency circuits |
| DE29602426U1 (en) * | 1996-02-12 | 1996-04-04 | Knuerr Mechanik Ag | Housings for electrical and electronic components, assemblies and / or subracks |
-
1996
- 1996-06-18 DE DE29610694U patent/DE29610694U1/en not_active Expired - Lifetime
-
1997
- 1997-06-17 EP EP97930332A patent/EP0906718B1/en not_active Expired - Lifetime
- 1997-06-17 AT AT97930332T patent/ATE196969T1/en not_active IP Right Cessation
- 1997-06-17 WO PCT/DE1997/001234 patent/WO1997049271A1/en not_active Application Discontinuation
- 1997-06-17 JP JP50208198A patent/JP3630240B2/en not_active Expired - Fee Related
- 1997-06-17 CZ CZ19984145A patent/CZ288037B6/en not_active IP Right Cessation
- 1997-06-17 SK SK1743-98A patent/SK174398A3/en unknown
- 1997-06-17 DE DE29710574U patent/DE29710574U1/en not_active Expired - Lifetime
- 1997-06-17 KR KR1019980710344A patent/KR20000016737A/en not_active Application Discontinuation
- 1997-06-17 CN CN97196361A patent/CN1111342C/en not_active Expired - Lifetime
- 1997-06-17 ES ES97930332T patent/ES2151735T3/en not_active Expired - Lifetime
- 1997-06-17 HU HU9903790A patent/HUP9903790A3/en unknown
- 1997-06-17 CA CA002258540A patent/CA2258540A1/en not_active Abandoned
- 1997-06-17 DE DE59702461T patent/DE59702461D1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CN1225231A (en) | 1999-08-04 |
| EP0906718B1 (en) | 2000-10-11 |
| DE59702461D1 (en) | 2000-11-16 |
| ATE196969T1 (en) | 2000-10-15 |
| HUP9903790A2 (en) | 2000-03-28 |
| EP0906718A1 (en) | 1999-04-07 |
| JP2000515316A (en) | 2000-11-14 |
| CN1111342C (en) | 2003-06-11 |
| SK174398A3 (en) | 1999-07-12 |
| CZ414598A3 (en) | 1999-07-14 |
| KR20000016737A (en) | 2000-03-25 |
| JP3630240B2 (en) | 2005-03-16 |
| WO1997049271A1 (en) | 1997-12-24 |
| CZ288037B6 (en) | 2001-04-11 |
| DE29610694U1 (en) | 1997-07-17 |
| ES2151735T3 (en) | 2001-01-01 |
| DE29710574U1 (en) | 1997-08-14 |
| HUP9903790A3 (en) | 2000-05-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |