Note: Descriptions are shown in the official language in which they were submitted.
109ZSZfi
Background of the Inventlon
With the advent of forced air heating and cooling
in homes, commercial buildings, manufacturing plants and the
- like, the use of air filters has become widespread. Initially
; 5 the air filter assemblies were difficult and costly to
manufacture and requently were awkward to handle. The
; frames utilized to accommodate the filter panels or pads
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were of costly construction because of the need for numerous
components requiring an inordinate amount of manual labor to
assemble. Frame constructions were subsequently improved by
significantly reducing the number of components and the -
amount of manual labor required. Such improved frame ~-
constructions, however, were not without shortcomings, e.g.,
they did not provide adequate support for the pliable filter
panel normally employed in such an assembly. Where in-
adequate support was provided for the filter panel, the - `~
latter became severely distorted when subjected to the flow
of air therethrough whereby in certain instances peripheral
- portions of the filter panel became disengaged from the
frame and thus, provided gaps through which the air could
flow unfiltered.
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~ In other instances, the prior frame constructions
- were susceptible to being torn or permanently deformed when
the latter was subjected to normal handling during shipping,
storage, or when being installed in a heating and/or air
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conditioning unit.
-~ Summary of the Invention
` Thus, it is an obiect of the invention to provide
an air filter assembly which is of simple, inexpensive, yet
sturdy construction, and is highly efficient in operation. -
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The invention provides an air filter assembly comprising a com-
pressible air pervious multisided filter panel, and a frame $n supporting
engagement therewith; said frame being formed from a single blank of fold-
able sheet material and including a foraminous center section having one
surface thereof in supporting face-to-face engagement with a surface of
said filter panel, a marginal section delimiting said center section and
having portions thereof corresponding to the multisides of said filter
. panel, and a plurality of elongated peripheral sections arranged in alternate
.~ sets and being foldably connected to the periphery of the marginal section,
each peripheral section having a segment coacting with a portion of said
marginal section to fixedly sandwich and compress therebetween an edge
, portion of said filter panel, said peripheral sections being foldably ad~ust-
able relative to one another from an inoperative position to an operative
position, said peripheral sections, when in said inoperative position, having
one alternate set of peripheral sections overlapping a second alternate set
:. of peripheral sections and said sets assuming a collapsed substantially ~:~
overlapping relation with respect to the filter panel compressed edge por-
tions and, when said peripheral sections are adjusted to said operative
position, said second alternate sets of peripheral sections havlng tab-like
.end portions automatically aligned with and inserted into ad~acent openings
formed in the ends of the ad~acent said one alternate set of peripheral
sections and effecting interlocking of said peripheral sections in corner- ~.
forming relation whereby a substantially continuous flange is formed pro- : :~
~ecting angularly away from a plane including said marginal section; the
peripheral sections of each alternate set, when in operative position,
projecting angularly from the marginal section towards said foraminous
center section to form an acute included angle whereby an elongated edge of
.~ . each perlpheral section overlies in spaced relation an ad~acent portion of
: the marginal section. :
: 30 The frame thereof is of unitary construction, is formed from a
blank of inexpensive sheet material and may be readily formed by conventional
automatic high-speed cutting, slotting and scoring equipment. The filter
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panel and the unitary frame may be assembled by automatic or semi-automatic
equipment. The periphery of the air filter assembly is reinforced thereby
facilitating handling of the assembly. A portion of the supporting frame
thereof may be collapsed so as to facilitate packaging of the assembly with
other like assemblies so as to occupy a minimal amount of space. The
collapsed portions of the supporting frame may be readily manipulated so as
to assume an operative position.
The invention also provides a blank of foldable sheet material for
use in an air filter assembly to form a supporting frame capable of being
collapsed for a multisided filter panel, said blank comprising a multisided
section having a foraminous central portion deliminted by a marginal por-
tion, said multisided section being adapted to supportingly engage one sur-
face of the filter panel, the multisides of the filter panel corresponding
substantially to the multisides of said section; and a plurality of elongated
peripheral sections foldably connected to the multisides of said section,
said peripheral sections being in adjoining relation and adapted to be folded
relative to one another to form a substantially continuous flange projecting
away from and delimiting the multisided section, the distal edge of the
flange defining an area less than the area of said multisided section, each
peripheral section including an elongated first flange segment connected by
a first foldline to a corresponding edge of the marginal portion, an elongated
second flange segment connected to said first flange segment by a second
foldline, the latter being shorter in length than said first foldline, each
first flange segment having end edges extending convergently from said first -~
foldline to said second foldline, and an elongated third segment connected
to said second flange segment by a third foldline, the distance between said
first and second foldlines being greater than the distance between said second
and third foldlines, said third segment being adapted to coact with said
marginal portion to sandwich therebetween an edge portion of the filter
panel, said first, second and third foldlines being in spaced substantially
parallel relatlon; corresponding flange segments of predetermined peripheral
sections having end tabs, each tab being foldable about a diagonally disposed
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1092526
fourth foldline and being adapted, when said blank is set up to form the
frame, to lockingly engage flange segments of an adjoining perlpheral section
and form a corner of the substantially continuous flange.
In one embodiment of the invention, the filter panel is of conven-
tional construction and is preferably formed of glass fibers held in a very
porous mass by a thermoset binder, e.g., phenol formaldehyde solution extended
twenty percent with an emulsion of VINSOL, a rosin derivative. The filter
panel is normally sprayed with a non-drying, non-volatile mineral oil. The
dimensions of the filter panel are normally of standard sizes and will
depend upon the size of the unit in which the assembly will be eventually
installed.
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Description
For a more complete understanding of the invention
reference should be made to the drawings wherein:
Fig. 1 is a plan view of one form of a frame blank.
used in the improved air filter assembly.
Fig. lA is an enlarged fragmentary plan view of
one corner of the blank shown in Fig. 1.
; Fig. 2 is a plan view of the upstream side of one
form of the improved air filter assembly.
Fig. 3 is a plan view of the downstream side of
the filter assembly of Fig. 2.
Fig. 4 is an enlarged fragmentary sectional view
taken along line 4-4 of Fig. 3.
Fig. 5 is an enlarged fragmentary perspective view
of one corner of the assembly of Fig. 2 and showing the
interconnecting tab of one peripheral section disengaged
from the end limit of an adjacent peripheral section forming ?
the corner in question.
Fig. 6 is an enlarged fragmentary side elevational
view taken along line 6-6 of Fig. 2 and with a portion of -
the first flange segment removed so as to show the dis- `~
position of the interc~nnecting tab in operative position. - ~
Fig. 7 is an enlarged fragmentary perspective view -
similar to Fig. 5 but showing portions of the peripheral
sections in a collapsed condition. - ~ `
Referring now to the drawings and more particular
to Figs. 2 and 3, one form of the improved air filter
assembly 10 is shown which is particularly suitable for use
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1092526
in a forced air heating and/or air conditioning unit, not
shown. The size and shape of the assembly will depend upon
the size and shape of the unit in which the assembly is to
be placed when in use. Basically, the assembly 10 comprises
a multisided filter panel or pad 11 and a supporting frame
12 associated therewith. The assembly 10 normally has a
rectangular or square peripheral configuration. The filter
; panel 11 is preferably formed of glass fibers, as disclosed
in detail in U.S. Patent 3,023,839. The normal thickness of
the panel 11 is approximately one inch, but may vary as
desired. The panel is very porous and the fibers thereof
are normally sprayed with non-drying, non-volatile mineral
oil thereby causing dust, or other foreign particles,
entrained in the flowing air to become deposited on the
treated glass fibers in a manner well understood in the art.
Because of the inherent flimsy pliable character of the
panel 11, it is necessary that it be supported by a frame
12.
The frame 12 is of unitary construction and is
preferably formed from a blank 13 of fiberboard or like
material. Such material is inexpensive, light weight and
yet is possessed of inherent stiffness to provide the
necessary support for the filter panel 11.
Blank 13, in one form, is shown in Figs. 1 and lA
and includes a foraminous or perforated center section 14
which is delimited by a marginal section 15 which is pre-
ferably imperforate. The center and marginal sections 14 -
and 15 combine to have a shape corresponding substantially
to the peripheral configuration of filter panel 11. The
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1092526
sections 14 and 15 are coplanar and engage in face-to-face
relation the downstream surface of the panel 11. That is to
say the surface from which the flowing air leaves the panel
11. Center section 14, as seen in Fig. 1, is provided with
rows of apertures 14a arranged in staggered relation.
Notwithstanding the large number of apertures 14a formed in
section 14, the latter will substantially resist bowing or
distortion of the panel surface due to the air flowing -
through the panel. Section 14 provides a minimal amount of
resistance to the air flow. Marginal section 15, as afore-
mentioned, is preferably imperforate so as to provide a
more effective surface to which the peripheral, or edge,
portion lla of the panel 11 is attached in a manner to be
described more fully hereinafter.
'! 15 In addition to the center and marginal sections 14
- and 15, the frame 12 includes a plurality of peripheral
sections 16 and 17 which are foldably connected to the side
edges of marginal section 15. Sections 16 and 17 are
generally of the same configuration except as will here-
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inafter be discussed. Sections 16 are arranged in one
alternate set with respect to sections 17 arranged in a
second alternate set, as seen in Fig. 2.
; Each section 16, 17, see Fig. 1, includes a first
flange segment 16aj 17a which is connected by foldline 18 to
the adjacent portion of the marginal section 15. Connected
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by foldline 20 to the opposite elongated distal edge of
; segment 16a, 17a is a second flange segment 16_, 17b. As
seen in Fig. 4, the first and second flange segments 16a,
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16b are disposed in substantially face-to-face fold back
relation when the blank is set up to form frame 12. Connected
by foldline 21 to the elongated edge of the second flange
segment 16_, 17_ is a third segment 16c, 17c. When the
frame and filter panel are assembled together, the third
segment 16c, 17c cooperates with the corresponding portion
of marginai section 15 and compresses a peripheral portion
lla of the filter panel 11 therebetween. The thermoset
binder of the panel coupled with a suitable adhesive applied
to the adjacent surfaces of the third segment and corres-
ponding portion of the marginal section 15 provide an
effective bond between the frame and filter panel.
. The width dimension W of the first flange segment
16a, 17a, which is measured bewteen foldlines 18 and 20, is
greater than the corresponding width dimension W' of the
second flange segment 16_, 17b, and as a result thereof the
flange segments, when folded relative to one another into an
operative position, form an inwardly protruding flange F,
- see Fig. 4. Furthermore, it will be noted in Fig. 4 that
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' 20 fold back segments 16a, 16b are not in contact with one
another, but instead are slightly spaced from one another so
as to form an elongated narrow pocket P, the function of
which will be discussed more fully hereinafter.
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In the blank embodiment illustrated in Fig. 1, the
second flange segment 16_ of each peripheral section 16 has
~ a longitudinally extending tab 22 connected by a foldline 23
- to each end thereof. When the blank 13 is set up in assembled
relation with the filter panel 11 and the peripheral sections
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~O9~S26
16, 17 are moved into an operative position, each tab 22 of
peripheral section 16 is folded about foldline 23 and
automatically aligns itself with and is inserted into a
corresponding opening of pocket P formed by the first and
second segments 17a, 17b of the adjacent peripheral section
17, see Fig. 6. Thus, the tabs 22 effect interconnection at
the corners of the frame and span the corner joints J
formed between the adjacent peripheral sections 16 and 17.
To facilitate insertion of the tab into the end of pocket P,
the narrow edge 17d is cut back as seen more clearly in Fig.
6. The tabs serve multi functions; for example, they
reinforce the corners, retain the adjacent peripheral
sections in proper angular alignment with respect to one
another, and reduce substantially air flow leakage at the
corners.
When the assembly 10 is to be shipped to the
customer in bulk, that is to say with a plurality of like
assemblies, and said assemblies are packaged or bundled
together, the peripheral sections 16, 17 of each assembly i
assume an inoperative collapsed state, as seen more clearly
in Fig. 7, thereby reducing significantly the thickness of
the assembly. Thus, the plurality of assemblies can be
arranged in a stacked relation and then compressed so as to
form a compact bundle or package, which is convenient for
shipping and/or storage. When the assembly is removed from
the bundle or package, the peripheral sections 16 and 17 are
manually folded upwardly to an operative position causing
each tab 22 to automatically align itself with the adjacent
opening to the pocket of section 17, whereupon, as the
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sections 16, 17 are released, they will automatically
assume their appropriate angular positions and the tabs will
be inserted into the adjacent pockets.
It will be noted in Fig. 7 that when the peripheral
segments 16, 17 are in a collapsed state, the tabs 22 and
associated end of the peripheral section 16_ to which it is
attached are overlapped by the adjacent end of section 17.
Because of the double thickness of the frame
flange F, the angular disposition of the flange sections 16,
17, and the interconnection between the sections 16, 17
` caused by the tabs 22, the frame 12 is possessed of an
inherent stiffness which greatly facilitates handling of the
assembly when it is being positioned in place within a
heating and/or air conditioning unit or being removed
lS therefrom. Furthermore, the frame prevents undesirable
distortion or bowing of the filter panel when it is sub-
jected to normal air flow. The frame blank can be readily
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foxmed by conventional, automatic high speed equipment and
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' assembled with the filter panel in an expeditious manner and
with a minimal amount of manual labor.
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I claim:
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