U.S. patent application number 13/593198 was filed with the patent office on 2014-02-27 for implementing press-lock emc gasket with absorber.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. The applicant listed for this patent is Don A. Gilliland, Rebeccah J. Vossberg. Invention is credited to Don A. Gilliland, Rebeccah J. Vossberg.
Application Number | 20140054082 13/593198 |
Document ID | / |
Family ID | 50147012 |
Filed Date | 2014-02-27 |
United States Patent
Application |
20140054082 |
Kind Code |
A1 |
Gilliland; Don A. ; et
al. |
February 27, 2014 |
IMPLEMENTING PRESS-LOCK EMC GASKET WITH ABSORBER
Abstract
A method and structures are provided for implementing press-lock
electromagnetic compatibility (EMC) gaskets. A gasket includes a
plurality of fasteners received through a plurality of
corresponding mounting apertures in a perforated support surface
for precise placement, and retention without adhesives. The
corresponding mounting apertures have a diameter smaller than
1/20th of a wavelength of the highest frequency to be suppressed to
remain independent of the shielding required. The gasket defines a
cavity receiving compliant foam, and includes an absorber.
Inventors: |
Gilliland; Don A.;
(Rochester, MN) ; Vossberg; Rebeccah J.;
(Rochester, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gilliland; Don A.
Vossberg; Rebeccah J. |
Rochester
Rochester |
MN
MN |
US
US |
|
|
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
50147012 |
Appl. No.: |
13/593198 |
Filed: |
August 23, 2012 |
Current U.S.
Class: |
174/351 ;
277/312 |
Current CPC
Class: |
H05K 9/0015
20130101 |
Class at
Publication: |
174/351 ;
277/312 |
International
Class: |
H05K 9/00 20060101
H05K009/00; H05K 13/04 20060101 H05K013/04 |
Claims
1. A structure for implementing for implementing a press-lock
electromagnetic compatibility (EMC) gasket comprising: a perforated
support member including a plurality of corresponding mounting
apertures; a gasket including a plurality of fasteners received
through said plurality of said corresponding mounting apertures in
said perforated support member for precise placement, and retention
without adhesives; said corresponding mounting apertures having a
diameter smaller than 1/20th of a wavelength of the highest
frequency to be suppressed; a gasket enclosure defining a cavity
receiving compliant foam; and an absorber received in said gasket
enclosure.
2. The structure as recited in claim 1 wherein said perforated
support member includes a perforated surface formed of an
electrically conductive material.
3. The structure as recited in claim 1 wherein said perforated
support member includes a perforated surface formed of an
electrically nonconductive material.
4. The structure as recited in claim 1 wherein each of said
plurality of fasteners includes a shaft and an enlarged resilient
head received through the corresponding mounting aperture.
5. The structure as recited in claim 4 wherein said enlarged
resilient head has a predefined profile for preventing easy
removal.
6. The structure as recited in claim 1 wherein said plurality of
fasteners include a fabric wrapping.
7. The structure as recited in claim 1 wherein said plurality of
fasteners are formed of an electrically nonconductive material.
8. The structure as recited in claim 1 wherein said plurality of
fasteners are formed of an electrically conductive material.
9. The structure as recited in claim 1 wherein said plurality of
fasteners includes a shaft and an enlarged resilient head received
through the corresponding mounting aperture, and said shaft being
electrically conductive and having a set diameter substantially
filling the corresponding mounting aperture for providing lower
impedance.
10. The structure as recited in claim 1 includes an absorber base
with an absorber positioned above the absorber base.
11. The structure as recited in claim 10 wherein said absorber base
is formed of RF absorber material.
12. The structure as recited in claim 10 wherein said absorber base
includes a conductive fill.
13. The structure as recited in claim 1 wherein said absorber is
formed of an RF absorber material including a selected one of an
electrically conductive elastomer material, and an electrically
nonconductive elastomer material.
14. The structure as recited in claim 1 wherein said enclosure s
formed of a selected one of beryllium copper and stainless
steel.
15. The structure as recited in claim 1 wherein said compliant foam
includes polyurethane foam.
16. A method for implementing a press-lock electromagnetic
compatibility (EMC) gasket comprising: providing a perforated
support member including a plurality of corresponding mounting
apertures; said corresponding mounting apertures having a diameter
smaller than 1/20th of a wavelength of the highest frequency to be
suppressed providing a gasket with a plurality of fasteners for
press-fit engagement into said corresponding mounting apertures;
providing a gasket enclosure defining a cavity receiving compliant
foam; and providing an absorber in said gasket enclosure; mounting
said gasket with said plurality of fasteners received through
corresponding mounting apertures for precise placement, and
retention without adhesive.
17. The method as recited in claim 16 wherein providing a gasket
including a plurality of fasteners includes providing said
plurality of fasteners with a shaft and an enlarged resilient head
received through the corresponding mounting aperture.
18. The method as recited in claim 17 wherein said plurality of
fasteners are formed of an electrically nonconductive material.
19. The method as recited in claim 17 wherein said plurality of
fasteners are formed of an electrically conductive material, and
said shaft having a set diameter substantially filling the
corresponding mounting aperture for providing lower impedance.
20. The method as recited in claim 16 wherein mounting said gasket
with said plurality of fasteners received through corresponding
mounting apertures includes compressing said compliant foam in said
cavity.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
electromagnetic compatibility (EMC) shielding, and more
particularly, to a method, and structures for implementing
press-lock electromagnetic compatibility (EMC) gaskets with an
absorber.
DESCRIPTION OF THE RELATED ART
[0002] As silicon technologies move toward smaller transistor sizes
with smaller feature sizes, packaging densities increase, and
operating frequencies increase, the need to contain or minimize
electromagnetic interference (EMI) increases.
[0003] Electromagnetic compatibility (EMC) requires shielding to
contain or minimize electromagnetic interference emissions from an
electronic circuit packaging design. Gaskets often are used to fill
and electronically bond and seal leaky apertures, for example, in
chassis or panel members in order to maintain a minimum shielding
effectiveness over a defined frequency spectrum.
[0004] In critical applications where varying temperature or normal
or shear forces prevent the use of adhesive, a mechanical method of
attaching a gasket is needed. Adhesives are sensitive to storage
conditions, shelf life, and application temperature, and the like,
controlling the variables and specifically storage conditions,
globally are difficult.
[0005] A need exists for effective structures for implementing
press-lock EMC gaskets with an absorber. It is desirable to provide
such structures for implementing press-lock EMC gaskets with an
absorber that have a generally simple configuration and are
generally easy to assemble and that are inexpensive to produce.
[0006] The term electromagnetic compatibility (EMC) should be
understood to include, and to be used interchangeably with,
electromagnetic interference (EMI), electrical conduction and/or
grounding, corona shielding, radio frequency interference (RFI),
and electro-static discharge (ESD) protection.
SUMMARY OF THE INVENTION
[0007] Principal aspects of the present invention are to provide a
method, and structures for implementing press-lock electromagnetic
compatibility (EMC) gaskets with an absorber. Other important
aspects of the present invention are to provide such method and
structures substantially without negative effects and to overcome
many of the disadvantages of prior art arrangements.
[0008] In brief, a method, and structures are provided for
implementing press-lock electromagnetic compatibility (EMC)
gaskets. A gasket includes a plurality of fasteners received
through a plurality of corresponding mounting apertures in a
perforated surface for precise placement, and retention without
adhesives. The corresponding mounting apertures have a diameter
smaller than 1/20th of a wavelength of the highest frequency to be
suppressed to remain independent of the shielding required. The
gasket defines a cavity receiving compliant foam, and includes an
absorber.
[0009] In accordance with features of the invention, the fasteners
include a shaft and an enlarged resilient head received through the
corresponding aperture for retaining the gasket with the perforated
surface. The enlarged resilient head optionally has a profile for
preventing easy removal. The fasteners optionally include a fabric
wrapping.
[0010] In accordance with features of the invention, the fasteners
are formed of either an electrically nonconductive or electrically
conductive material, for example, a plastic material or a metal
material. An electrically conductive shank of the fasteners
optionally includes a diameter filling the corresponding mounting
apertures for providing lower impedance.
[0011] In accordance with features of the invention, the gasket
includes an absorber base disposed above the cavity receiving
compliant foam carrying a second absorber positioned above the
absorber base. The absorber base optionally is formed of an RF
absorber material, such as a selected one of electrically
conductive elastomer materials, or electrically nonconductive
elastomer materials including for example, a flexible metal fill in
a polymer resin or a flexible magnetic fill in a polymer resin.
[0012] In accordance with features of the invention, the cavity
receiving compliant foam optionally includes a conductive fabric
coating with an absorber positioned on the outside of the
conductive fabric coating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention together with the above and other
objects and advantages may best be understood from the following
detailed description of the preferred embodiments of the invention
illustrated in the drawings, wherein:
[0014] FIG. 1 is an exploded perspective view not to scale of an
example press-lock electromagnetic compatibility (EMC) gasket with
an absorber in accordance with a preferred embodiment;
[0015] FIG. 2 is a perspective view not to scale illustrating an
intermediate assembly of the press-lock electromagnetic
compatibility (EMC) gasket with an absorber of FIG. 1 in accordance
with a preferred embodiment;
[0016] FIG. 3 is a perspective view not to scale illustrating a
complete assembly of the press-lock electromagnetic compatibility
(EMC) gasket with an absorber of FIG. 1 in accordance with a
preferred embodiment;
[0017] FIG. 4 is a perspective view not to scale illustrating
another example press-lock electromagnetic compatibility (EMC)
gasket with an absorber in accordance with a preferred
embodiment;
[0018] FIG. 5 is a perspective view not to scale illustrating the
press-lock electromagnetic compatibility (EMC) gasket with an
absorber of FIG. 4 mounted with a perforated surface in accordance
with a preferred embodiment; and
[0019] FIG. 6 is a perspective view not to scale illustrating
another example shank panel fastener for use in the press-lock
electromagnetic compatibility (EMC) gaskets with an absorber in
accordance with a preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] In the following detailed description of embodiments of the
invention, reference is made to the accompanying drawings, which
illustrate example embodiments by which the invention may be
practiced. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from
the scope of the invention.
[0021] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0022] In accordance with features of the invention, a method, and
structures are provided for implementing press-lock electromagnetic
compatibility (EMC) gaskets with an absorber. A gasket includes a
plurality of fasteners received through a plurality of
corresponding mounting apertures in a perforated support member for
precise placement, and retention without adhesives. The
corresponding mounting apertures have a diameter smaller than
1/20th of a wavelength of the highest frequency to be suppressed to
remain independent of the shielding required.
[0023] Having reference now to the drawings, in FIGS. 1-3, there is
shown not to scale an example press-lock electromagnetic
compatibility (EMC) gasket with an absorber generally designated by
the reference character 100 in accordance with a preferred
embodiment.
[0024] As shown in exploded view in FIG. 1, the press-lock
electromagnetic compatibility (EMC) gasket 100 includes a gasket
perforated member generally designated by the reference character
102, a plurality of fasteners generally designated by the reference
character 104 fitted in a base member generally designated by the
reference character 106, a gasket cavity enclosure generally
designated by the reference character 108, and an enclosure member
generally designated by the reference character 110.
[0025] The gasket perforated member 102 includes an upper
perforated surface 120. The gasket perforated member 102 includes a
plurality of generally centrally located apertures 122 and a
plurality of notches 124 spaced apart along each side of the
member. As shown in FIGS. 2 and 3, the plurality of fasteners 104
are received through the apertures 122 and notches 124 in the
electromagnetic compatibility (EMC) gasket 100.
[0026] Each of the fasteners 104 includes an enlarged resilient
head 130 and a shaft 132 fitted in the base member 106. The
enlarged resilient head 130 is received through the apertures 122
and notches 124 in the gasket perforated member 102.
[0027] In use the press-lock EMC gasket 100 is mounted to a chassis
or panel perforated supporting member by the plurality of fasteners
104 in press-fit or press-lock engagement with the enlarged
resilient head 130 passing through a perforated surface and
essentially locks in place preventing easy removal. The fasteners
104 optionally have a profile, for example, including the enlarged
resilient head 130 for preventing easy removal.
[0028] The gasket cavity enclosure 108 is filled with compliant
foam 136, such as polyurethane foam and optionally includes an
absorber, such as an absorber 504 shown in FIG. 5, or supports an
absorber 302 as shown in FIG. 3.
[0029] The gasket enclosure member 110 includes a base or bottom
140 and a pair of side walls 142 extending from the bottom wall 140
defining an opening, as shown in FIGS. 1-3, for receiving the
gasket cavity enclosure 108. The side walls 142 include spaced
apart slots 144 corresponding to the notches 124 in the perforated
member 102 for receiving the fasteners 104 positioned along the
sides of the base member 106. The slots 144 are defined in the side
walls 142 by a first pair of end sections 146, a plurality of
interior sections 148, and a second pair of end sections 150.
[0030] The gasket enclosure member 110 is formed of a selected
material having sufficient strength and electromagnetic
compatibility properties, such as a selected one of beryllium
copper and stainless steel. For example, the gasket enclosure
member 110 is formed of a thin sheet of beryllium copper or
stainless steel. It should be understood that other rigid or
compliant material having sufficient strength and electromagnetic
compatibility properties can be used to form the gasket enclosure
member 110.
[0031] Referring to FIG. 2, there is shown an intermediate assembly
generally designated by the reference character 200 of the
press-lock electromagnetic compatibility (EMC) gasket 100 in
accordance with a preferred embodiment. In the illustrated
intermediate assembly 200 of the press-lock EMC gasket 100, gasket
enclosure member 110 contains the gasket cavity enclosure 108 with
compliant foam 136, the base member 106 fitted with the plurality
of fasteners 104 received through the apertures 122, and notches
124 of the perforated member 102 and the slots 144 of the gasket
enclosure member 110.
[0032] Referring to FIG. 3, there is shown a complete assembly
generally designated by the reference character 300 of the
press-lock electromagnetic compatibility (EMC) gasket 100 with an
absorber 302 in accordance with a preferred embodiment. The
absorber 302 is formed of an RF absorber material, such as a
selected one of electrically conductive elastomer materials, or
electrically nonconductive elastomer materials including for
example, a flexible metal fill in a polymer resin or a flexible
magnetic fill in a polymer resin.
[0033] In the illustrated complete assembly 300 of the press-lock
EMC gasket 100, the side wall sections 146, 148, 150 of the gasket
enclosure member 110 are folded over, containing the interior
gasket cavity enclosure 108 with compliant foam 136, the base
member 106 fitted with the plurality of fasteners 104 received
through the apertures 122, and notches 124 of the perforated member
102.
[0034] As shown the illustrated complete assembly 300 in FIG. 3 of
the press-lock EMC gasket 100 is mounted to a chassis or panel
perforated supporting member by the plurality of fasteners 104 in
press-fit or press-lock engagement. The enlarged resilient head 130
of the fasteners is received through the corresponding aperture for
retaining the gasket with the associated perforated support member,
such as a supporting member 510 shown in FIG. 5.
[0035] Referring to FIGS. 4 and 5, there is shown another example
press-lock electromagnetic compatibility (EMC) gasket with an
absorber generally designated by the reference character 400 in
accordance with a preferred embodiment. The press-lock EMC gasket
400 includes a perforated member 402, a first gasket cavity
enclosure 404, an absorber base 406, a second gasket cavity
enclosure 408, and a plurality of fasteners 410.
[0036] Each of the plurality of fasteners 410 includes an upper
enlarged resilient tapered head 112, an intermediate enlarged
portion 114, and a shank 116 fitted in or through the perforated
member 402. The fasteners 410 have a profile including for example,
the enlarged resilient tapered head 112 together with the
intermediate enlarged portion 114 for preventing easy removal when
mounted with an associated supporting member 510, as shown in FIG.
5.
[0037] Compliant foam is provided in each of the first gasket
cavity enclosure 404 and the second gasket cavity enclosure 408.
The press-lock EMC gasket 400 includes a respective absorber 502,
504 received within the cavity 404, 408 with the compliant foam
420, 422, as shown in FIG. 5.
[0038] Referring to FIG. 5, there is shown an assembly generally
designated by the reference character 500 of the press-lock
electromagnetic compatibility (EMC) gasket 400 with associated
perforated supporting member 510 in accordance with a preferred
embodiment.
[0039] As shown in FIG. 5, in the assembly 500, the press-lock EMC
gasket 400 is mounted with the plurality of fasteners 410 received
through corresponding mounting apertures for precise placement, and
retention without adhesives in a supporting member 510 in
accordance with a preferred embodiment.
[0040] The absorber 302 of the press-lock EMC gasket 100 and the
absorber 502, 504 of the press-lock EMC gasket 400 are formed of RF
absorber material including a selected one of an electrically
conductive elastomer material, and an electrically nonconductive
elastomer material. The absorbers 302, 502, 504 optionally a
flexible metal or magnetic fill, for example, contained in a
polymer resin, and can include an aluminum foil shielding
layer.
[0041] In the assembly 500, the press-lock EMC gasket 400 is
mounted within the supporting member 510 by the fasteners 410 and
the compliant foam 420 under the fasteners 410 is compressed to the
proper force and held into place with the back side of the
fasteners 410.
[0042] Referring to FIG. 6, there is shown not to scale another
example fastener generally designated by the reference character
600 in accordance with a preferred embodiment. The fastener 600
advantageously is used in the press-lock electromagnetic
compatibility (EMC) gaskets 100, 400 in accordance with a preferred
embodiment.
[0043] The fastener 600 includes a generally tapered profile
generally designated by the reference character 602 extending
between an upper surface 604 and a lower surface 606. The fastener
600 includes a lower shank 608 and an enlarged section 610 received
through the corresponding aperture for retaining the gasket 100,
400 with the associated perforated support member, such as a
supporting member 510 shown in FIG. 5. The fastener 600 includes
spaced apart elongated recesses or groves 612, 614 extending
between the upper surface 604 and lower surface 606.
[0044] The fasteners 104, 410, and 600 are formed of either an
electrically nonconductive or electrically conductive material, for
example, a plastic material or a metal material. The fasteners 104,
410, and 600 optionally include a fabric wrapping, and are spaced
apart in rows allowing enough room for spacing between the rows to
facilitate fabric wrapping.
[0045] The absorber base 406 of the press-lock EMC gasket 400 and
members 102, 106 of the press-lock EMC gasket 400 is formed of RF
absorber material. The absorber base 406 and members 102, 106 could
be provided with a conductive fill, such as a Faradex compound to
further increase EMC effectiveness.
[0046] While the present invention has been described with
reference to the details of the embodiments of the invention shown
in the drawing, these details are not intended to limit the scope
of the invention as claimed in the appended claims.
* * * * *