Note: Descriptions are shown in the official language in which they were submitted.
0;364;~4
DOOR 5TIFFENER
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¦ a~ "round
Z51 It has become popular in home, apartment, and mobile
home constxuc~ion to use lightweight closet dooxs that slide
or ~old. These doors have a thin panel, typically 3/16 or l/4
inch ~hi~1c, providing the pxlncipal ~urface area o~ the door.
A uertically extendin~ steel ~tile i8 clipped onto the panel
3 nlong each side edg~ ~nd a steel rail ~8 ~irnilarly mounted at
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11 10364Z4
the top and bottom o the panel. Specla~ corner connec~or~
that en8~ge the s~Lile and rsll are provided nt each oorner
~or securing the door components together lnto an ~ntegral
~tructure. These corner connectors also have door mountlng
hardware, such as wheels or guides for sliding doors.
. Some installations have a pair of fold~ng doors
intereonnec~2d by hinges between ad,~acen~ corner connectors.
The corner connectors on the door nearest the ~amb have pivots
~hut support ~heJcwo doors and permit fold~ng. The ¢orner
:~ 10 conneetors fur~chest ~rom the jamb on ~he ~econd door have
guide~ thac run in tracks wl~hin the door rame to main~ain
the doors in Qlignment.
U. S. Patent NoO 3,750,337 entitled "Sliding Door Corner
: Connector'l describes a typ~cal door with ~teel rails and ~iles
15 and a typical corner connector. The door stif~ener described
hexeln i8 particularly adapted to such a panel door having
ra~ls as descr~bed in that patent. P~ncip~l utility is with
folding rathex than sliding doors. It will become apparent
that it ¢an easlly be adapted to other panel doors,
When a pair of folding doors are mounted in a door frame,
. ~he welgh~ o both doors is supported a~ the p~vots on the
On2 door nearest the jamb. This xaises no problem when ~he
doors are closed, that i5, when the door panels are
substantially coplanar. When the doo~s are open however the
weight dlstribu~on o the supported door remo~e from the jamb
: tends to tWi9~ the support~ng or "plvot" door nearer the jamb.
The p~nel, stlles and rail~ in uch a lightweight door may
not have suf~icient torsional stiffness ~o adequ~tely resist
the loa~ing imposed and the fiupportlng door may rack ou~ of a
30 plane. Thè e~fec~c ~s a8 i~ ~he top edge of the pivot door
were twisted clockwise ~ ~ o~ Zp~ ane and the bottom of the
door counterclockwise (~or vice versa~. A relatively small twist,
which can easily occur ïn a lightweight door, can cause the
outer door to jam in the tracks and make opening and closing
difficult.
It is therefore desirable to provide a means for enhan-
cing the torsional rigidity of the supporting door to resist the
twisting tendency.
Brief S~nary of the Invention
In accordance with the present invention there is
provided door stiffener components for installation in a door
comprising:
a torsion bar having a hollow polygonal transverse cross-
section; and
a pair of clamps slidably movable along the length of
the torsion bar for connecting the torsion bar to a door,
each of said clamps comprising:
a generally L-shaped member having one sheet for
engaging the face of a door and a second sheet for engaging the
torsion bar;
a window through a center portion of the second sheet
having a shape substantially complementary to the cross section
of the torsion bar and sufficient clearance therefrom to permit
longitudinal sliding of the clamp along the torsion bar sub-
dividing the second sheet into two parts; and
web means connecting the two parts of the second sheeton opposite sides of the window for pulling the two parts closer
together and against the side of a torsion bar in a window.
There is, therefore, provided in practice of this
invention according to a presently preferred embodiment door
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stiffener components for stiffening a door comprising a torsion
~` bar extending substantially the length of the door~ The torsion
bar is connected to the door by clamps at the top and bottom,
respectively. Each of the clamps has a flat face sheet
connected tightly against the face of the door adjacent an end
~, and a connector sheet noxmal to the face sheet and integral
therewith. The connector sheet has a window defining a web
of connector sheet between the window and the free edge of the
sheet remote from the face of the door. The window has a shape
complementary to the cross section of the torsion bar and
sufficient clearance to permit sliding along the length of the
bar. The web adjacent the window is twistable out of the
place of the connector sheet for pulling the sides of the
window tightly against the torsion bar.
Dra~ings
These and other features and advantages of the present
invention will be appreciated as the same becomes better
understood by reference to the following detailed description
of a presently preferred embodiment when considered in
connection with the accompanying drawings wherein:
FIGURE 1 is a rear view of a pair of folding doors with
the door stiffener in place;
FIGURE 2 is a perspective detail of one end of the door
stiffener during an intermediate state of installation;
FIGURE 3 is a face view of one of the door stiffener
clamps;
FIGURE 4 is a transverse cross section through the
stiffener torsion bar, and
FIGURE 5 is a perspective view similar to Figure 2
with the stiffener fixed in place.
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1~)369~Z~
Description
Figure 1 is a rear view of a pair of typical folding
doors with which the door stiffener provided herein is useful.
Such a view would be from inside a closet, for example. This
assembly has a pivot door 10 which in use is mounted adjacent
the door jamb (not shown). A second supported door 11 is
connected to the pivot door by hinges 12 at the top and bottom
respectively. Such hinges may, for example, be like those
described in U.S. patent Serial No. 3,846,868 entitled "Corner
Connector and Hinge ~or Door with Hollow Stile" and assigned
to Acme General Corporation, assignee of this application. If
desired an optional center hinge 13 may be included between
the top and bottom of the two doors.
Each of the doors 10 and 11 has a stile 14 extending
along each side edge. Rails 16 are provided along the top
and bottom edges of each of the two doors. A corner connector
17 including a pivot is provided in each corner of the pivot
door adjacent the jamb. These pivots fit into conventional
pivot brackets (not shown) for supporting the two doors. The
supported door 11 has a corner connector 18 in each corner
remote from the hinges, including guides that ride along
conventional tracks (not shown) in the top and bottom of the
door frame to maintain alignment of the doors during folding.
The structure described to this point is all conventional and
is similar to that described in the above-identified patents.
As mentioned above the pivot door in the pair can be
; subject to racking that makes opening and closing difficult.
Stiffening of the pivot door is therefore provided by a door
stiffener comprising a torsion bar 19 extending substantially
the full height of the door and a pair of identical end clamps
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~036~Z4
21 at the top and bottom of the door, respectively.
An end of the torsion bar l9 and one of the end clamps
21 is illustrated in perspective in the fragmentary view of
Figure 2. The clamp is a generally L-shaped piece stamped
and bent from sheet steel. One leg of the L is a face sheet
22 which lies flat against the back face of the door panel 23.
An edge portion of the face sheet slips between the door panel
and the rail 16. The rail in this embodiment has a generally
U-shaped cross section and includes a doubled-back flange 24
that engages the back face of the door panel and extends
towards its edge. The face sheet 22 includes a pair of
stamped barbs 26 that readily slide under the flange 24 but,
in reverse, catch against it and prevent the clamp from being
withdrawn. In a typical embodiment the rail 16 is sufficiently
springy that the clamp can be readily pressed in place by hand
preasure alone.
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I ~3642~
1 ¦ The clamp also ha3 a connector ~heet 27 norm~l to the
¦ face shee~ 22 so tha~ when lnstalled on the door the connector
¦ ~heet extends ~earwardly. A~ may be better ~een in FXG. 3
¦ the connector sheet has a hat-shaped window 28 havlng its
S ¦ base adjacent the face sheet 22 and ex~endlng a~ay from it.
¦ A pair of ~mall bosses 29 are stamped in the connector ~heet
¦ ~o provide some s~iffeni~g adjacent the corners 41 extending
into ~he window. The outer portion o the windo~ 28
nearer the free edge of the connector sheetj that is remote
10¦ from thc door panel~when installed, defines a web 31 of the
: connector sheet, the`importance of which will appear
hereinafter. Small notches 32 opposite the outer corners 42
o~ the w~ndow 28 narrow and somewhat weaken the web. A
circular hole 33 i~ also provided through the center portion
o~ the web.
The torsion bar 19, which ~ seen ln transverse cross
: section ~n FIG. 4, is preferably roll ormed from steel.
The tor~ion bar is generally square ~n cross sec~io~ and one
leg has a longi~udinally extendlng flange 34. The adjacent
leg has ~n inwardly directed channel 36 and an extending edge
37 that curls around the flange 34. The ~lange 34 and curled
edge 37 collectively form a side ~lange running the length of
the torsion bar. The curled edge 37 kaeps the flange 34
from sh~fting outwardly and the channel 36 keeps ~t from
~5 sh~fting inwardly, thereby firmly locking ~he ad~acent legs
o~ the torsion bar ~ogether.
; The longitudinally extendîng flange is periodically
stamped through the 1ange 34 and bo~h layers of the curled
edge 37 1:o produce rai~ed half-moon bump~ 38 on one ~ace end
30 corre~polldin~ dimples on ~hc opposi~e ~ce, These in'cermittent
1~ l
1 I stamped regions sheAring through all ~hree layers irmly lock
¦ the longitudlnal flange ~ogether. I~ wil~ be apparent to one
¦ skilled in the art that this cross sec~ion o~ torsion bar can
¦ be readily m~de by pro~ressive roll orming. It will also be
5 ¦ apparent ~hat, i~ desired, a bar o~ generally similar
. ¦ rectangular cross section, with o~ withou~ a lateral 1~nge,
¦ can be m~de by ex~rus~on or welding.
¦ ~te window 28 in ~he connector sheet has a shape
I complemen~ary to that of the torsion bar 19 80 that ~che
.10¦ clamp readily slides along the leng~h of ~he bar, The base
I openlngs 39 of th~ ha~-shaped window simply provide clearance
¦ for the flange along one edge of the tsrsion bar, and i ~
completely ~quare cross section i8 used, these base portion
¦ openings can be elimin~ted and a substantially square window
15¦ provided through the connec~or 6heet. Two base portions 39
¦ ~re provided even t:hough there ~8 but a single flange on the
~. I torsion bar 50 that similar clamps c~n be usecl at the top and
I ¦ bottom of the door.
¦ The window 28 i~ not quite square for a s~uare toxsion
~, 20¦ bax. The window i9 actually slightly trapezoidal with the
protruding corners 41 closer together than the window corners
42 adjacent the web. The taper is slight, amount~ng to only
abou~ 0.012 inch greater wid~h ~n a window nominally 3/4 inch
~quare. The resul~ is that ~here i.9 about 0.006 lnch grea~er
~5 clearance on e~ch side o the torsion bar ad~acent the web than
there is adjacent the protruding corners 41.
To in~tall the door stifener the torsion bar iæ placed
against the back o~ the door with the two clamps mounted
thereon 80 that ~heir ~ace sheets point in opposite directi.ons
30 and can lie ~l~t agains~ the door p~nel, The torsion bar 1~
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I ~036~4
l ¦ positloncd with it~ ends elose to bu~ not overlapping the end
¦ rails 16 at ~he top and bo~om o~ the door respec~ively, and
¦ prt~erably it is centered between the gtiles and p~rallel
l ~hereto. The two end clamps are then each pushed under ~heir
5~ respective rail ~o ~has the barbs 26 pass beyond the 1anges 24,
¦ One then lnserts a pin 43 through ~he hole 33 from ~he
¦ ~ide towards the end of the door as illus~ra~ed in phan~om in
FIG. 20 A nail ~et, punch, or other s~rong pin can be used,
The outer end o the pin ~s then ti~ted or swung ~round as
lndicated by the arrows to brlng the pin down ~o a position
adjacent the ~orsion bar as illustrated in FIG. 59 The pin
i~ removed after this single operation.
Tiq~ing the pin while in the hole 33 twists ~he web 31
ou~ of the plane of the connector sheet ~7. The center
p~r~ o the web between the hole 33 and ~orsion bar i8
twisted out o the plane in one direction and thè por~ion
on the oppos~te side of the hole is twisted out o~ the plane
ln the opposite direc~ion, The resul~ant twist blends
relatively gradually into the balance of the connector sheet,
although it i8 more pronounced between the window corners
41 and the notches 32, The twisting shortens the effective
length o the web and pu118 the side~ of the window tightly
agains~ the s~des of the torsion bar, B~cause o~ the lever
like action very t~ght engagemen~ o the clamp on the ~orsion
~5 bar is obtained. This tight engagement prevents s liding of
the bar and clamps relat~ve to each other, but most impor~antly
~t enables transm~ssion o torsion loads therebetween.
Torsional forces a~ the door ~tt~mp~s to rack are conveyed
from the panel to the connector ~hee~, one edge o which is
30 against the panel. These orce~ ~re in turn transmi~ted to
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1 1~36424
1 ¦ the torslon bar at it~ enga~ement with the slde~ of the window,
¦ The torsional rigidity of this inexpens~ve and easily installed
¦ tors~on bar effectively eliminates racking o the pivot door ln
¦ a folding door set.
When twisting o~ the web close~ the sides of the window
~gainst ~he sides of the torsion bar there i8 a greater de~ree
- of closure nearer the web than ne2rer the face æheat, It will
be recalled that the window ii8 not quite square bu~c i8 slightly
tr~pezoidal and relatiYely wider adjacent the web. As the
window closes on the ~orsion bar the sides become more nearly
parallel and engagement of the sides of the window with the
torsion bar extends over an appreciable length o the window
. ~ide instead o merely being at the corners 42 a6 would be
the case i~ the window were originally æquare. The same
15 efect is obta~ned from a square window and ~ligh~cly
trapezoldal torsion member, I'c will also be no~ced thas ~he
bosses 29 limit twisting o~ the connec~or sheet ~n the
region adjacent the sldes of the windows and prevent the
protruding corners 41 from twisting out of the plane of
20 the connector ~heet.
Since the door panel i8 relatively lightweight and the
torsion bar extends the full length thereo there is a
: pos~ibili~y of some flu~ter or rattling of the door as it
:~ is used~ This possibility can be readily avoided by
ZS placing a thin rubber bumper between torsion bar and door
panel near the middle, or some flexible mastic or adhesive
can be put in the same loca~ion.
Although a hollow square torsion bar is preferred because
of its lnherent torsional rigidity and the large area of
contact between the connector sheet and torsion bar, other
.
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1 ¦ cross~sec~ion~l sh~pcs may ~lso be sui~able, Pre~rably ~he
¦ bar ~s poly~on~l rather than circular in C~05~ section since
¦ there is d~fficulty in tr~nsmi~ing the torsion l~ads to a
¦ circular ~orsion bar by clamping action and welding or
51 mechanical fasteners are ~xpensive or relatively unsuitable
. for field application. When the torsion bar has more sides
than ~our, it tends ~o approach circularity and transfer of
loads there~o by clamping action is more difficul~ ~han w~th
a square bar, A ~riangular torsion bar fitted th~ough a
triangular window can be employed with the apex o the
~criangle relat:ively nearer the door 80 tha~ its base lies
par~llel to ~he face sheet and deines a connector sheet web
for twisting. The area of engagement between the clamp and a
. ~rl~ngular ~orsion bar is generally less than available when
lS the torsion bar ~s square.
Many other modifications and var~ations in the presen~
i~ven~on will be apparent to one s~illed in the axt. Thus,
: . ox example, the end clamps on the torsion bar can be connected
to ~he face o the door panel by other means such as strong
~0 adhesive or mechanical astene~s~ Modifications o the
face sheet for engagemen~ with other rails fur hdlding the
face sheet in engagement with the door panel can alsc be
provided, Various pat~erns of stiffening ribs or weakening
no~ches can also be provided in the cl~mps 80 that they can be
Z5 fabricated of lighter gauge steel.
It will also be noted that in lieu o twisting ~he web
ln a direction in line with the torsion bar that the same
xesult o~ clos~ng the window can be obtalned by a transver~e
twist. ~ spanner type tool straddling ~he web ~an be used
for applyin~ 8uch a twi9~ or one can ~imply use ~trong plier~.
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1 ¦ Twistin~ ~s de~cribed hcreinabove is prcerrcd, howevcr, since
¦ one 19 rcacting one portion of tile we~ a~ainst ~nother portlon
¦ and there is no resul~ant twis~ on the clamL) as a whole w~ich
¦ mi~ht tcnd to dl3engnge it ~rom the rail. A similar ef~ect
¦ could be obtained with a ~hreaded member in~ OEconnec~ng
¦ ~eparated portlons o the connector sheet on opposite sldes
¦ of the window, but this would be more costly to m~ke and install.
¦ Many other modiflcatiorls and varlations will be apparent to
one skilled in the ar~ and it i8 thereox~ to be under~tood
that within the scope o~ the appendéd cla~m3 the invention m~y
be practiced o~cherwise ~chan as specifically descsibed.
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