U.S. patent application number 12/263155 was filed with the patent office on 2010-05-06 for system and method for clamping a chassis cover.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Brooks S. Mann, Terence G. Ward, George R. Woody, Edward P. Yankoski.
Application Number | 20100109351 12/263155 |
Document ID | / |
Family ID | 42130476 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100109351 |
Kind Code |
A1 |
Woody; George R. ; et
al. |
May 6, 2010 |
SYSTEM AND METHOD FOR CLAMPING A CHASSIS COVER
Abstract
A system is provided for securing a cover having a first surface
onto a chassis having a rim, the rim having a second surface. The
system comprises a clamping rail and a fastener coupled to the
rail. The clamping rail is configured to form a loop that
circumferentially engages the first surface and the second surface
and, when constricted, produces a first force substantially
coplanar with the loop. The fastener is configured to constrict the
rail, the rail and the first and second surfaces configured to
produce a second force having a component substantially orthogonal
to the loop when the rail is constricted.
Inventors: |
Woody; George R.; (Redondo
Beach, CA) ; Yankoski; Edward P.; (Corona, CA)
; Ward; Terence G.; (Redondo Beach, CA) ; Mann;
Brooks S.; (Redondo Beach, CA) |
Correspondence
Address: |
INGRASSIA FISHER & LORENZ, P.C. (GM)
7010 E. COCHISE ROAD
SCOTTSDALE
AZ
85253
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
42130476 |
Appl. No.: |
12/263155 |
Filed: |
October 31, 2008 |
Current U.S.
Class: |
292/256.69 ;
292/256.67; 292/256.73 |
Current CPC
Class: |
F16B 5/0635 20130101;
Y10T 292/216 20150401; Y10T 292/214 20150401; Y10T 292/221
20150401 |
Class at
Publication: |
292/256.69 ;
292/256.67; 292/256.73 |
International
Class: |
B65D 45/34 20060101
B65D045/34; B65D 45/32 20060101 B65D045/32 |
Claims
1. A system for securing a cover having a first surface onto a
chassis having a rim, the rim having a second surface, the system
comprising: a clamping rail configured to form a loop that
circumferentially engages the first surface and the second surface
and, when constricted, produces a first force substantially
coplanar with the loop; and a fastener coupled to the rail
configured to constrict the rail, the rail and the first and second
surfaces configured to produce a second force having a component
substantially orthogonal to the loop when the rail is
constricted.
2. A system according to claim 1, wherein the fastener further
comprises a threaded rod coupled to the rail, the threaded rod
configured to adjustably constrict the rail.
3. A system according to claim 1, wherein the fastener further
comprises a lever rotatably coupled to the rail and having a closed
position, the lever configured to constrict the rail when the lever
is actuated into the closed position.
4. A system according to claim 1, wherein the fastener is rotatably
coupled to the clamping rail.
5. A system according to claim 1, wherein the clamping rail is
coupled to a backing strap.
6. A system according to claim 1, wherein the fastener is coupled
to a backing strap.
7. A system according to claim 1, wherein the clamping rail further
comprises an upper arm that engages the first surface and a lower
arm that engages the second surface.
8. A system according to claim 7, wherein the upper and lower arms
have different lengths.
9. A system according to claim 7, wherein the rim further comprises
a corner and the upper and lower arms of the rail are notched
proximate to the corner.
10. A system according to claim 1, wherein the rail further
comprises corner braces, and wherein the fastener is coupled to the
corner braces and is configured to constrict the rail by adjusting
the corner braces.
11. A system according to claim 1, wherein at least one of the rim
and the cover further comprises a groove, and further comprising a
seal that engages the groove and seals the chassis when the cover
is clamped onto the rim.
12. A system according to claim 1, wherein the rim further
comprises a corner and the fastener is configured to conform to the
corner.
13. A system according to claim 1, wherein the clamping rail is
further configured to reduce electromagnetic interference passing
between the cover and the rim.
14. A method for clamping a cover having a first surface onto a
vehicular chassis body having a rim, the rim having a second
surface, the method comprising the steps of: circumferentially
aligning a clamping loop to the first and second surfaces;
constricting the circumference of the clamping loop to engage the
first and second surfaces with a first force substantially coplanar
with the loop, the clamping loop and the first and second surfaces
being configured to convert at least a portion of the first force
to a second force substantially orthogonal to the loop that clamps
the cover onto the rim; and fixing the clamping loop in its
circumferentially restricted position.
15. The method of claim 14, further comprising the step of
inserting a seal between the cover and the rim.
16. The method of claim 14, wherein the clamping loop further
comprises a first end and a second end and the step of fixing the
clamping loop further comprises fixing the clamping loop by welding
the first and second ends together.
17. A system for clamping a cover onto a rim of a vehicular
chassis, the cover having a first surface residing in a first
plane, and the rim having a second surface residing in a second
plane, the system comprising: a clamping rail circumscribing the
first and second surfaces, the clamping rail comprising: a first
arm configured to engage the first surface and residing in a third
plane; and a second arm configured to engage the second surface and
residing in a fourth plane, the rail generating a clamping force
that clamps the cover to the rim when the rail is constricted and
at least one of the first plane and the second plane is different
than the third plane and the fourth plane, respectively; and a
fastener coupled to the rail configured to constrict the rail.
18. A system according to claim 17, wherein the chassis further
comprises a corner, and the first and second arms are notched
proximate to the corner.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to clamps, and more
particularly relates to a system for clamping a cover to a power
electronic bay chassis.
BACKGROUND OF THE INVENTION
[0002] In recent years, advances in technology have led to
substantial changes in the design of automobiles. One of the
principal changes involves the complexity, as well as the power
usage, of various electrical systems within automobiles,
particularly alternative fuel vehicles. During this time, the
requirement for electrical power generation in automotive
applications has risen dramatically. This trend had been in place
for decades but has accelerated in the last few years largely due
to the advent of hybrid, electric, and fuel cell based vehicles.
Such vehicles often use electrochemical power sources, such as
batteries, ultracapacitors, and fuel cells, to power the electric
motors that drive the wheels, sometimes in addition to another
power source, such as an internal combustion engine.
[0003] In hybrid and fuel cell vehicles, a Power Electronics Bay
(PEB) performs many necessary functions related to power conversion
and distribution. PEB enclosures or chassis are typically designed
to provide housed components with both environmental protection and
shielding from incoming and outgoing electromagnetic interference
(EMI). A PEB chassis generally comprises a body and cover
constructed of either stainless steel or aluminum, each member
having a machined sealing flange along an outer edge, pre-drilled
to accommodate fastening bolts. One or both of the flanges
typically has a groove to support a metal-impregnated, conductive,
silicone o-ring to form an environmental seal when the cover of the
enclosure is bolted closed. EMI shielding is provided by the
continuous conductive shrouding formed by the metallic structure of
the body and cover in conjunction with the conductivity of the
o-ring in the seam. Because strong and evenly distributed clamping
pressure is needed to provide a reliable seal, reinforcement of
sealing flanges is typically required to provide adequate rigidity
and prevent warping from the substantial compressive forces
generated by a plurality of bolts spaced 1'' to 2'' apart. As a
result, part count and overall vehicle weight are increased along
with the complexity of associated assembly processes. Further,
conductive, EMI shielding o-rings are often nickel-filled and add
additional expense while contributing no additional environmental
protection compared to conventional, non-conducting silicone rubber
o-rings.
[0004] Accordingly, it is desirable to provide a system for
clamping a cover to a PEB chassis that is easily installable and
eliminates the need for multiple fasteners. Further, it is
desirable that such a system provides EMI shielding along the seams
and corners of a PEB chassis without the use of a conductive
o-ring. Furthermore, other desirable features and characteristics
of the present invention will become apparent from the subsequent
detailed description and the appended claims, taken in conjunction
with the accompanying drawings and the foregoing technical field
and background.
SUMMARY OF THE INVENTION
[0005] A system is provided for securing a cover having a first
surface onto a chassis having a rim, the rim having a second
surface. The system comprises a clamping rail and a fastener
coupled to the rail. The clamping rail is configured to form a loop
that circumferentially engages the first surface and the second
surface and, when constricted, produces a first force substantially
coplanar with the loop. The fastener is configured to constrict the
rail, the rail and the first and second surfaces configured to
produce a second force having a component substantially orthogonal
to the loop when the rail is constricted.
[0006] A method is provided for clamping a cover having a first
surface onto a chassis body having a rim, the rim having a second
surface. The method comprises the steps of circumferentially
aligning a clamping rail to the first and second surfaces,
constricting the circumference of the clamping loop to engage the
first and second surfaces with a first force substantially coplanar
with the loop, the clamping loop and the first and second surfaces
being configured to convert at least a portion of the first force
to a second force substantially orthogonal to the loop that clamps
the cover onto the rim, and fixing the clamping loop in its
circumferentially restricted position.
DESCRIPTION OF THE DRAWINGS
[0007] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and
[0008] FIG. 1 is a schematic view of an exemplary automobile
illustrating the manner in which an embodiment is integrated with
various sub-components of an automobile;
[0009] FIG. 2 is an isometric view of a power electronics bay
enclosure in accordance with a first embodiment of the present
invention;
[0010] FIGS. 3-5 are cross-sectional schematic drawings
illustrating clamping rails in accordance with further embodiments
of the present invention;
[0011] FIGS. 6-7 are isometric views of a clamping rail in
accordance with a further embodiment of the present invention;
[0012] FIG. 8 is an isometric view of a clamping rail and corner
brace in accordance with yet a further embodiment of the present
invention;
[0013] FIGS. 9-10 are isometric views of a clamping rail and
fastener in accordance with yet a further embodiment of the present
invention;
[0014] FIG. 11 is an isometric view of a clamping rail integrated
with a lever-actuated fastener in accordance with yet a further
embodiment of the present invention;
[0015] FIG. 12 is an isometric view of a clamping rail corner
structure in accordance with yet a further embodiment of the
present invention; and
[0016] FIG. 13 is an isometric view of a clamping rail welded in
accordance with yet a further embodiment of the present
invention.
DESCRIPTION OF AN EXEMPLARY EMBODIMENT
[0017] FIG. 1 illustrates a vehicle 10, (e.g. an automobile),
according to one embodiment of the present invention. The
automobile 10 includes a chassis 12, a body 14, four wheels 16, and
an electronic control system (or electronic control unit (ECU)) 18.
The body 14 is arranged on the chassis 12 and substantially
encloses the other components of the automobile 10. The body 14 and
the chassis 12 may jointly form a frame. The wheels 16 are each
rotationally coupled to the chassis 12 near a respective corner of
the body 14.
[0018] The automobile 10 may be any one of a number of different
types of automobiles, such as, for example, a sedan, a wagon, a
truck, or a sport utility vehicle (SUV), and may be two-wheel drive
(2WD) (i.e., rear-wheel drive or front-wheel drive), four-wheel
drive (4WD), or all-wheel drive (AWD). The automobile 10 may also
incorporate any one of, or combination of, a number of different
types of engines (or actuators), such as, for example, a gasoline
or diesel fueled combustion engine, a "flex fuel vehicle" (FFV)
engine (i.e., using a mixture of gasoline and alcohol), a gaseous
compound (e.g., hydrogen and/or natural gas) fueled engine, or a
fuel cell, a combustion/electric motor hybrid engine, and an
electric motor.
[0019] In the exemplary embodiment illustrated in FIG. 1, the
automobile 10 is a fuel cell vehicle, and further includes an
actuator assembly (or powertrain) 20, a battery 22, a battery state
of charge (SOC) system 24, a power electronics bay (PEB) 26, and a
radiator 28. The actuator assembly 20 includes an internal
combustion engine 30 and an electric motor/generator (or motor)
system (or assembly) 32. The battery 22 is electrically coupled to
the PEB 26 and, in one embodiment, comprises a lithium ion (Li-ion)
battery including a plurality of cells, as is commonly understood.
PEB 26 is typically comprised of a plurality of electronic
components, including those operating with high voltage, enclosed
in a housing or chassis that provides protection from both
environmental damage and shielding for incoming and outgoing
EMI.
[0020] FIG. 2 illustrates an exemplary PEB chassis 120 that houses
electronic components in accordance with a first exemplary
embodiment. These components may include a DC/DC converter 122 to
boost fuel cell DC voltage to a higher voltage, a DC/AC inverter
124 for delivering AC power to a primary electric drive motor, an
additional DC/AC inverter 126 to deliver power to a compressor, a
set of boost inductors 130 to boost fuel cell output voltage as
part of the boost converter, and one or more circuit boards 132
containing support electronics for a myriad of functions. PEB
chassis 120 has a body 144 comprised of a rectangular bottom panel
146, four side panels 148 interconnected together, and a removable
top or cover panel 152. Body 144 is typically constructed from a
conductive and corrosion resistant material such as rolled
stainless steel sheets welded at side and bottom seams, or from a
die-cast and anodized aluminum alloy. Likewise, cover 152 is also
constructed of stamped sheet metal or a cast aluminum alloy, and is
fabricated to fit over the top of body 144. Any of the
side/top/bottom panels of chassis 120 may be specifically
configured to include contours and/or openings such as port 153 to
accommodate internal components housed therein, and/or provide a
means of interconnection to other components of vehicle 10. While
FIG. 2 illustrates PEB chassis 120 as a rectangular prism, it
should be understood that other shapes may be used depending on the
space and size constraints of the application and the type and size
of components to be housed. Further, while FIG. 2 illustrates only
clamping for a cover panel, it should be understood that any
non-integrally connected side and/or bottom panel may also be
clamped.
[0021] Referring to FIG. 2, a clamp 160 comprises a continuous rail
164 having first and second ends 172 and 173 respectively, coupled
together by an adjustable fastener 156 to form a clamping loop 150.
Fastener 156 may be used to precisely contract or expand the
circumference of clamp 160 to a desired circumference by providing
a means to controllably adjust the distance between first and
second ends 172 and 173. Prior to clamping, fastener 156 may be
loosened to expand the circumference of clamp 160 and facilitate
alignment to clamping surfaces of cover 152 and sidewalls 148. When
clamped, rail 164 conformably circumscribes these surfaces and
applies constrictive forces about cover 152 and sidewalls 148 that
are substantially coplanar with clamping loop 150. As will be
described in greater detail below, rail 164 is configured to engage
with cover 152 and sidewalls 148 and apply clamping pressure
thereto by converting the coplanar forces to clamping forces having
a component substantially orthogonal to loop 150.
[0022] FIG. 3 illustrates a cross sectional schematic drawing of
cover 152 aligned over sidewall 148 and proximate to clamping rail
164 prior to clamping in accordance with an exemplary embodiment.
The upper edge of sidewall 148 comprises an integrally formed rim
168 having a surface 198 machined to engage a flat machined
undersurface 200 of cover 152. A groove 192 is formed in rim 168
and runs along its length, and a seal 188 sized somewhat larger
than the width and depth of groove 192, is disposed therein. Types
of seals that may be used include but are not limited to o-rings,
gaskets, or curable liquids/gels. Alternatively, undersurface 200
may be configured to receive a seal, or both rim surface 198 and
undersurface 200 may each be grooved to accommodate a seal.
[0023] Prior to clamping, cover 152 rests on the top of seal 188
forming a gap 218 between undersurface 200 and rim surface 198. The
underside of rim 168 comprises a rim bevel 216 that extends outward
from sidewall 148 terminating with a vertical rim lip 176. The top
peripheral surface of cover 152 has an edge bevel 214 terminated by
a short vertical cover lip 190. Rail 164 is configured to fit over
edge bevel 214 and rim bevel 216 when clamped and comprises a
center section 208 that couples together upper and lower arms 202
and 204 respectively. Each arm may terminate with an outwardly
curving upper and lower leading edge 206 and 226 respectively, to
facilitate aligning rail 164 with rim 168 and cover 152 prior to
clamping. While rail 164 has been illustrated as having angled,
symmetric upper and lower arms 202 and 204, it should be understood
that arms may be asymmetric with respect to angle and/or length.
For example, as illustrated in FIG. 4, cover edge bevel 214 and rim
bevel 216 differ with each other with respect to both length and
bevel angle. Similarly, upper arm 202 and lower arm 204 of rail 164
differ in length and in angle from center section 208. In general,
rail 164 imparts a clamping force that clamps cover 152 to rim 168
when the plane of upper arm 202 is different than the plane of
cover edge bevel 214, and/or the plane of lower arm 204 is
different than the plane of rim bevel 216.
[0024] FIG. 5 illustrates a cross sectional schematic drawing of
cover 152, rim 168, and rail 164 in a closed and clamped position
in accordance with the exemplary embodiment. Rail 164 has been
moved into a clamping position by a force (depicted by arrow F1)
substantially coplanar with loop 150 and generated by, for example,
tightening fastener 158 (FIG. 2) to decrease the circumference of
clamp 160. As the circumference is decreased, F1 increases and
upper and lower arms 202 and 204 are pulled (inward toward the
center of loop 150) onto edge and rim bevels 214 and 216 causing
rail 164 to deform conformably to these bevels. When deformed, rail
164 responds in a springlike manner and generates forces comprising
opposing (clamping) components, F1 and F2, substantially orthogonal
to the plane of loop 150 that are applied to edge and rim bevels
214 and 216, and press cover 152 onto rim 168. Clamping forces F2
and F3 may be increased by further tightening of fastener 158 until
either the spring force decreases due, for example, to rail 164
yielding in plastic deformation or until center section 208 abuts
against rim lip 176 and/or cover lip 190. As clamping pressure
increases, seal 188 is compressed in conformity with cover 152 and
groove 192 to create a tight environmental seal. Clamping forces F2
and F3 may be controlled by a proper adjustment of fastener 158 to
retain a narrow gap 218, and avoid permanent deformation or
scarring of undersurface 200 and/or top surface 198 thereby. As is
well known by those with skill in the art, available clamping
forces can be adjusted by design factors that include but are not
limited to the angle and/or lengths of edge and rim bevels 214 and
216, the angle and/or length of the upper and lower rail arms 202
and 204, the spring constant of rail 164, and the applied force
F1.
[0025] Rail 164 provides EMI shielding over gap 218 all along its
length including around chassis corners as will be described in
further detail below. Such shielding results from factors that
include the metallic construction and shape of rail 164, and
reduces the amount of EMI passing between rim 168 and cover 152
from sources either internal or external to a chassis. Center
section 208 of rail 164 may be configured to be substantially
perpendicular to gap 218 to provide improved coverage and greater
attenuation of such EMI signals.
[0026] FIG. 6 illustrates an isometric view of a clamp 240 in
accordance with another exemplary embodiment. Clamp 240 is
configured for a rectangular chassis and comprises a first and
second L-shaped section of clamping rail 236 and 238 respectively,
each rail having a cross-sectional geometry suitable for clamping
in accordance with this invention such as that depicted for rail
164 in FIG. 3. A first backing strap 230 is mounted to first rail
236 in a parallel fashion, and traverses conformably along its
entire length. A second backing strap 232 is likewise conformably
mounted parallel to second rail 238. Each strap 230 and 232 is
comprised of a rolled carbon steel or stainless steel alloy sheet
attached to its respective rail using rivets, spot-welds, or the
like. First and second rails 236 and 238 are coupled together to
form a rectangular loop using first and second fasteners 246 and
248 respectively. Fasteners 246 and 248 are each configured to be
tightened or loosened to adjust the peripheral distance spanned by
clamp 240. Prior to clamping, fasteners 246 and 248 may be loosened
to expand the peripheral distance and facilitate mounting and
alignment of clamp 240 to the rim and cover of a chassis. Following
alignment, clamp 240 may be constricted by tightening fasteners 246
and/or 248 to generate a clamping force. While clamp 240 has been
shown having two opposing corner fasteners, those having skill in
the art will appreciate that clamp 240 may be configured with a
single corner fastener or with more than two corner fasteners
depending upon space and/or other overall design
considerations.
[0027] FIG. 7 illustrates the interaction of first and second
backing straps 230 and 232 with fastener 246 disposed at a corner
of clamp 240 in accord with an exemplary embodiment. Fastener 246
is comprised of a t-bolt 262 having a fixed head 250, and slidably
coupled to a crosstie 260. In one embodiment, t-bolt 262 is bent to
more conformably accommodate a corner. Crosstie 260 may slide in
either direction along t-bolt 262 and is bounded between a nut
assembly 254 and head 250. Nut assembly 254 is threadably coupled
to t-bolt 262 and, when tightened, forces second crosstie 260
controllably toward head 250. First backing strap 230 is divided at
its end and forms a pair of loops 265 each rotatably coupled to an
end of head 250 forming a first hinge 269. Second backing strap 232
is similarly split to form a second hinge 271 rotatably coupled to
the ends of second crosstie 260. The hinged coupling of fastener
246 to backing straps 230 and 232 allows clamp 240 to adjust more
conformably and apply pressure more evenly in chassis corners.
Prior to clamping, nut assembly 254 may be loosened to allow
separation of head 250 and crosstie 260, and expansion of clamp 240
thereby. To apply clamping pressure, nut assembly 254 may be
tightened to force head 250 and crosstie 260 toward each other,
constricting clamp 240 thereby.
[0028] FIG. 8 is an isometric view of a fastening assembly 298
configured for clamping a chassis corner in accordance with an
exemplary embodiment. First and second clamping rails 300 and 302
may represent end segments of longer rail sections of a clamp 296
fabricated for a rectangular chassis. First rail segment 300 and
second rail segment 302 have first and second bent ends 304 and 306
respectively, contoured to conformably engage with a first and
second corner brace 308 and 3 10. An adjustable fastener 320 is
comprised of first and second crossties 322 and 324, respectively,
that slidably engage first and second corner braces 308 and 310
along a threaded rod 312. A nut 318 threadably coupled to a first
end 321 of rod 312 may be rotated to adjust the distance between
the crossties and braces, and by their engagement, to adjust the
distance between first and second bent ends 304 and 306
respectively. Prior to clamping, clamp 296 may be expanded to
facilitate alignment to a chassis cover/rim by loosening nut 318.
Clamp 296 may be constricted to apply clamping pressure using nut
318 to adjust the distance between first and second braces 308 and
310 and thus also first and second bent ends 304 and 306.
[0029] FIG. 9 is an isometric view of a clamp assembly 270 in
accordance with another exemplary embodiment. Clamp assembly 270 is
configured for a rectangular chassis and comprises first and second
rails 276 and 278, respectively, each rail formed in the shape of
an asymmetric U having two right angle bends. Rails 276 and 278 are
coupled together along straight rail sections by a first and second
adjustable fastener 272 and 274. As in previous embodiments, one or
both of fasteners 272 and 274 may adjust the circumference of clamp
270 by loosening for alignment or removal, or by tightening to
apply clamping as required. An isometric side view of an exemplary
fastener 272 in accordance with this embodiment is illustrated in
FIG. 10. Fastener 272 is configured in a similar manner to fastener
246 shown in FIG. 7, and comprises a threaded rod 280 coupled to a
first crosstie 282 at a first end 293, and slidably coupled to a
second crosstie 288 and a hollow sleeve 284. First crosstie 282 is
rotatably coupled to a first backing loop 290 to form a first hinge
294, and second crosstie 288 is likewise rotatably coupled with a
second backing loop 292 to form a second hinge 295. Backing loops
290 and 292 are each attached to ends of rails 276 and 278
respectively in a well-known manner using a rivet or weld. A nut
286 may be rotated to move sleeve 284 along rod 280 and adjust the
distance between first and second crossties 282 and 288. Fastener
272 may thus be loosened to expand clamp 270 to facilitate
alignment to or removal from a chassis, or tightened to contract
the circumference of clamp 270 to apply clamping pressure.
[0030] FIG. 11 is an isometric side view of a lever-actuated
fastener 360 used to couple together first and second clamping
rails 362 and 364, respectively, forming a clamp 361 in accordance
with a further embodiment. Fastener 360 comprises a lever 368
having a first end 380 configured with an angled leading edge 384
to facilitate actuation by a user. Lever 368 has a second end 382
rotatably hinged to a first base 378 by a pin 366. First base 378
is attached to first rail 362 using rivets, spot-welds, or the
like. A second base 374, having an upwardly curved catch 372, is
mounted to second rail 364 similarly using rivets, spot-welds, or
the like. A U-shaped latch 370 straddles lever 368 and has first
and second (not shown) hooked ends 376 and 377, respectively, that
are rotatably coupled either side of lever 368 via openings
therein. Latch 370 comprises a loop 373 configured to engage catch
372 when in a locked position and is free to swing about lever 368
when not engaged. Prior to clamping, lever 368 is rotated about pin
366 clockwise (as shown) to an unlocking position by applying an
upward force to the underside of leading edge 384. In the unlocking
position, latch 370 moves toward and disengages from catch 372,
enabling adjustment of first and second rails 362 and 364 to allow
clamp 361 to be aligned to or removed from a chassis. Fastener 360
is brought into a locking position by first engaging loop 373 with
catch 372, followed by rotating lever 368 into a locked position
over first base 378 (as shown). When fastener 360 is in the locked
position, the resulting circumference of clamp 361 is fixed and
depends on the lengths of first and second rails 362 and 364 as
well as on the placement and dimensions of fastener 360. Achieving
a desired circumference that will result in a desired clamping
pressure therefore requires precise placement and sizing of these
components.
[0031] FIG. 12 illustrates an isometric side view of a clamping
rail 350 configured to conform to a chassis corner in accordance
with an exemplary embodiment. Rail 350 has a cross section similar
to that of rail 164 shown in FIG. 3 and comprises an upper and
lower arm 340 and 342 respectively, coupled to a center section
338. Portions of upper arm 340 and lower arm 342 are removed in the
region of rail 350 adjacent to a chassis corner to form upper and
lower notches 332 and 334, respectively, and a center bridge 336
thereby. Those having skill in the art will appreciate that the
depth, width, and/or shape of notches 332 and 334 may be varied
provided that bending rail 350 to accommodate a corner does not
result in deformation and/or structural damage to arms 340 and 342
or bridge 336. Notching of rail 350 may reduce clamping pressure
somewhat in corners. This condition may be mitigated by minimizing
the width of notches 332 and 334 and/or by designing the cover and
rim to have greater rigidity in corner regions. EMI shielding
remains continuous in chassis corners due to the continuity of
bridge section 336 overlying the cover/rim seam around such
corners.
[0032] FIG. 13 illustrates an isometric view of a clamp 390 having
a circumference fixed by a weld in accordance with an exemplary
embodiment. Clamp 390 is configured for a rectangular chassis and
comprises a single clamping rail 394 having four right angle bends,
each bend configured with corner notches 396 as depicted in FIG. 12
and previously described. Rail 394 is fabricated from a weldable
material such as a carbon or stainless steel and has first and
second ends 398 and 400, respectively, pre-cut to a circumference
compatible with a chassis to be clamped. Prior to clamping, first
and second ends 398 and 400 may be freely adjusted to align rail
394 to the chassis cover/rim. After alignment, first and second
ends 398 and 400 are forced together using an appropriate means to
constrict the circumference of clamp 390, and joined with a weld
392. In further embodiments, first and second ends 398 and 400 may
be riveted, clasped, or crimped together. When joined using any of
these methods, the circumference of clamp 390 is fixed and applies
a corresponding clamping pressure to the chassis cover/rim. Fixing
rail 394 in this manner may be used when access to the interior of
the chassis for periodic maintenance of its contents is deemed
unnecessary.
[0033] While at least one exemplary embodiment has been presented
in the foregoing detailed description, it should be appreciated
that a vast number of variations exist. It should also be
appreciated that the exemplary embodiment or exemplary embodiments
are only examples, and are not intended to limit the scope,
applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing the
exemplary embodiment or exemplary embodiments. It should be
understood that various changes can be made in the function and
arrangement of elements without departing from the scope of the
invention as set forth in the appended claims and the legal
equivalents thereof.
* * * * *