Note: Descriptions are shown in the official language in which they were submitted.
697
This invention relates to pre -cut and pre-assem-
bled knocked down door frames made of wood which can be used
in the construction industry for door framing openings in par-
titions, using miter end wood components, normally soft wood
components.
In an attempt to reduce construction costs in
domestic housing building projects, various attempts have
been made in order to facilitate the door framing opera-
tions when customary soft wood components are used.
One approach consists of using a completely as-
sembled door frame with a pre-hung door panel in position,
which assembly comprised doorjambs and doorstops with
mouldings already secured along one of the two edges of
the doorjamb member; and once the pre-hung assembly is
secured in place to the vertical and horizontal studs in
the partition, the carpenter secures a moulding to the
other edge of the jamb members to complete the installa-
tion. This first approach presents a major storage and
transportation inconvenient in that such pre-hung assem-
blies are quite bulky and fragile.
An other approach consists of making knock-
ed down door frames for standard size doors, and an
example of this system is found in United States Patent
No. 3,440,783 issued on April 29, 1969 to M.L. Hughes.
In such cases, the knocked down door frames consist of
three assemblies namely two side post assemblies having
a squared lower end and an upper miter end, and a lintel
assembly mitered at both ends. In some cases the hinge
plates are already secured to the corresponding side post
-- 1 --
-" ` 1177697
and the strike plate may be mounted to the opposite side
post, which greatly facilitates the door hanging operations.
However, the main inconvenient of this system is that the
miters are nearly always imperfect on account of the fact that
some of the components of these assemblies abut each other
at the miters. For example, in the above noted Hughes patent,
the jamb members are cut at 90 degrees so as to cause abutting
engagement with the lintel member of the horizontal assembly.
The doorstops also normally meet at 90 degrees in an abutment
relationship. In view of the fact that these assemblies are
made of soft wood and that consequently it is not possible to
maintain accurate dimensions, even when great care is exercised
at the point of manufacture, such prior knocked down door
frames do not normally produce tight fits at all four miters
of the frame unless considerable adjustment is undertaken and
carefully effected on the construction site by a skilled
carpenter. An other good example of this type of knocked down
door frames is found in United States Patent No. 3,040,390
issued on June 26, 1962 to W.H. Carlton, where a rabbet joint
is resorted to; but it has been found that with this approach
it is equally difficult to obtain acceptable miters at the
meeting ends of the mouldings and at those of the doorstop.
Attempts to solve such difficulties are
disclosed in the following United States patents:
2,781,559, February 19, 1957, Savoie
3,060,522, October 30, 1962, Parker
3,239,978, March 15, 1966, Parker
3,338,008, August 29, 1967, Sklar
However, hitherto the construction industry did
not have a completely satisfactory system of knocked down
/J
1177697
door frame made of wood and affording perfect miter joints
with the strict minimum labour skill and time as low cost.
For example, in the case of the Parker system (3,239,978) a
relatively complex system of corner clips and adjustment
threaded devices is used which requires time consuming and
careful positioning and adjustment. In the case of Sklar,
the mouldings are slidably mounted in order to allow for
final adjustments at the time of installation on the cons-
truction site, which of course partly defeats the purpose
of using knocked down door frames which is to save time and
costs and permit the construction of acceptable door frames
by unskilled labor.
The principal object of this invention is to
provide a knocked down door frame which comes as three pre-
assembled assemblies having miter ends and a method of
erecting same without shims or any similar means of adjust-
ment within the minimum amount of time by unskilled hands
so as to obtain properly fitted miters.
I have found that these objects can be met by
using a lintel assembly mitered at both ends at the point of
manufacture after permanent assembly of the various wooden
components of such lintel assembly, and by using side post
assemblies whose upper ends are likewise mitered once the
various components thereof had been permanently pre-assembled.
In accordance with this invention, I provide a downwardly
projecting rigid tongue at each miter end of the lintel
assembly and a closely conforming deep slot at the upper end
of each side post assembly.
The method of building a door frame according
to my invention involves affixing the lintel assembly to the
.~
. ` ~
77697
horizontal stud of the door opening, at a predetermined height
and strictly horizontal; positioning a first side post assem-
bly on the adjacent vertical stud by first inserting the
projecting tongue of the adjacent miter end of the lintel
assembly into the corresponding deep slot followed by moving
this side post assembly to its vertical position while complet-
ing the tongue insertion process; nailing this first side post
assembly to its adjacent stud while said assembly is held
strictly vertical; positioning and nailing the other side post
assembly in the same manner; and completing nailing as
required.
Cross-pieces are secured to the inner surface of
the main plank of each assembly near the miter ends so as to
prevent warping, and these cross-pieces which are secured to
the side post assemblies define, at least partially, the deep
slots for the tongues of the lintel assembly.
In the accompanying drawings which illustrate a
preferred embodiment of this invention,
Figure 1 is a front elevational view of a door
frame with the lower part thereof broken away,
Figure 2 is a cross-sectional view at enlarged
scale taken along line II-II of Figure 1,
Figure 3 is a cross-sectional view along line III-
III of Figure 1 but at a scale which is the same as that of
Figure 2,
Figure 4 is a longitudinal partial cross-
sectional view taken along line IV-IV of Figure 3,
Figure 5 is a perspective view of an L-shaped
clip to be used at each miter joint in accordance with this
invention,and
Figure 6 is a perspective view of a cross-piece
designed to prevent jamb warping.
-- 4 --
.
~77697
Referring now more specifically to Figure 1, the
door frame is shown generally at reference numeral lO as
comprising lintel assembly 12, and two side post assem-
blies 1~ and 15 which generally conform with sufficient --
play to the rough opening in partition 20 as defined by -
.. ...
vertical studs 21 and 22 and horizontal stud 23, shown in --
.. ...
dotted lines in Figure 1. -:::
In accordance with this invention, and as will
be described below in greater detail, each assembly 12, ~=:
- .
14 and 15 comprises a central frame member with two oppo-
.:..:::..:.
site mouldings permanently secured to opposite edges of
:..........
the central member and forming a channel-shaped assembly
adapted to extend over the marginal edges of the plaster
- . .
board 25 already mounted to studs 21, 22 and 23 of the -
....=...
partition. These pre-assembled side post assemblies 14
and 15 and lintel assembly 12 are secured in place by
means of a plurality of finishing nails driven into the
...........
outer marginal edges of the mouldings into the underlying
vertical studs 21, 22 and horizontal stud 23 respective-
...... -.-
ly. This avoids the need to use shims or any other type
...... -.. .
of adjusting means; the close fitting nature of these mi-
e~
tor end subs-assemblies elimina.es the fitting procedure
and assures tight miters.
This structure is ~-)etter illustrated in Figure 2 -- -
. .
which is taken along line II-II of Figure 1. The illus- -^-
trated structure of the partition comprises a vertical ~-
;~:
stud 22 and plaster boards 25 already secured in place to
.. .
the studding of the partition by suitable means such as
.
.- ..- . . .
. . . - .
1177697 1
nails or screws (not shown) in accordance with convention~
. ......
al building techniques. Side post assembly 14 comprises - --
doorjamb member 30 of essentially constant, rectangular .... :.
cross-section having a main planar outer surface 32, an .
:.. :......................................................................... :
inner surface 34, an outer side edge 36 and an inner side -- .
edge 38. The casing of this structure consists of an in- ~
ner jamb moulding 40 and an outer jamb moulding 42 whose
respective inner marginal edges 44 and 46 are secured to , -
~ "':'"-:"'"'''
and cover the inner and outer side edges 36 and 38 of
doorjamb member 30. Mouldings 40 and 42 extend parallel ---
to their associated side edges 36 and 38 in the same di- ..
rection away from outer surface 32 so as to define, with
.... ..
doorjamb member 30, a channel-shaped assembly 14.
The structure of mouldings 40, 42 is convention~
al. The moulding illustrated in Figure 2 is relativey ~-
thin and wide having a thicker region 48 where the mould-
ing is nailed to the plaster board 25 and vertical stud 22
as at 50. The other portion of the moulding which is ad- .. -.. -
jacent doorjamb 30 is thinner and rounded as at 52 and it
presents an inner flat marginal edge 44 or 46 which is .
.
adapted to abut the corresponding side edge 36 or 38 of -
the doorjamb member 30. The connection of mouldings 40, -
42 to the doorjamb member 30 may be effected by means of .. --
small nails but the preferred mounting consists of a layer
of glue disposed between side edges 36 and 38 on the one
hand and inner edges 44 and 46 on the other and staples as .... -.
at 60 which are used primarily for maintaining the pieces .~ .
together until the glue has set.
.. ~
1177697
Where a door panel, such as at 62, is intended
to be hung to the door frame 10, a doorstop 64 is secured
longitudinally of doorjamb member 30 about centrally thereof
and it should be sufficient to use staples 66 without any glue
for this purpose. Of course where no door panels are to be
hung to frame 10, or where folding doors or other forms of
closure are to be installed to the frame 10, doorstop 64 may
be omitted.
The inner surface 34 of jamb member 30 prefer-
ably comprises a relatively wide and shallow groove 70
extending longitudinally of jamb member 30, normally the full
length thereof, for assisting in the proper alignment of side
post assembly 14 relative to the lintel assembly 12 at the
time of installation of the door frame 10, with the assistance
of L-shaped clips at each miter as will be described in greater
detail below. This groove 70, along the main inner surface 34
of doorjamb member 30, was also found to limit warping of
doorjamb member 30 when such is made of relatively green wood
as is often the case.
The components used for making the above descri-
bed side post assembly 14 are normally soft wood, for example
pine or cedar, and doorjamb member 30 may come in different
sizes in order to accomodate partitions of different thick-
nesses. Side post assembly 15 is identical to assembly 14.
A main feature of the present invention resides
in the fact that side post assemblies 14 and 15 , as de-
scribed above are entirely constructed at the point of
li776g7
manu~acture and their miter ends are cut only once every --
component has been permanently secured together. Thus,
the ends of every component of these assemblies lie in
common planes and therefore are even with one another.
..... ::.
The lower end (not shown) of side post assembly 14 is cut
at 90 degrees (preferably also at the point of manufac-
ture) in order to properly fit adjacent the floor around - -
the base of partition 20, and the upper end 72 of each
side post assembly is cut at a 45 degree angle relative
to the main outer surface 32 of doorjamb member 30 so that - -
the ends of the various components making up each side ,---
post assembly lie in exactly the same plane. The miter r~,::::::,,=,
~- ' "'''" '
end is necessarily cut at the point of manufacture.
Lintel assembly 12, one end of which is seen in ---
Figure 3, is constructed in exactly the same fashion as t-
side post assemblies 14 and 15 and it comprises a lintel
member 74 which also has a groove 76 on the center of its ~ `
inner surface 78. Each of its side edges 82 and 84 sup- -
port mouldings 86 and 88 in the exact same position as -
applicable in the case of mouldings 40 and 42 in side post
assembly 14 illustrated in Figure 2. Inner lintel mould-
ing 86 does not have to be exactly the same as outer -
lintel moulding 88 but it should be of the same shape and -
dimensions as inner doorjamb moulding 40 otherwise their -
miter joints will not fit closely. Likewise outer lintel -~-
.
moulding 88 must be of the same configuration and dimen-
sions as outer doorjamb moulding 42. -~
.... .. .
. . .
11~
..:
Figure 3 is a corner cross-sectional view taken
along line III-III of Figure 1 and it illustrates the nor~
:~ ......
mally hidden side of a Siter joint where lintel assembly
12 meets the upper end 72 of side post assembly 14.
.....
Figure 3 also shows L-shaped clip 90 in position bridging
the meeting ends of lintel assembly 12 and of side post
...........
assembly 14. This clip 90 is preferably made of a flat ~ --
strip of spring steel bent to form a right angle or an ---
- - -
angle which is slightly less than 90 degrees as shown in ~ -
Figure 5. Clip 90 comprises a first arm 92 which has a `
hole 93 in the middle for receiving a small wood screw 94 -- -
.. ::..
for retaining clip 90 to lintel member 74. The right -
. ,.
angle arm 96 of clip 90 is designed to be received into -
, ......
groove 70 of door jamb member 30 when side post assembly ---
14 is properly mounted. The function of clip 90 is to
guide side post assembly 14 relative to the position of
the adjacent miter end of lintel assembly 12 and conse- -
. . ..
quently the width of arms 92 and 96 of clip 90 should '
,.......
correspond to that of grooves 76 and 70 respectively. In -
order to obtain a sliding engagement of arm 96 into groove -
70, the width of arm 96 should be slightly less than that
........
of groove 70. For ease of manufacture these grooves are --
.. ....
of identical dimension and consequently clip 90 is made
. :.::-..-:::
of a flat strip of even width. The exact positioning of ---
.-
L-shaped 90 is perhaps better shown in Figure 4, which is
. . .
a partial longitudinal cross-sectional view taken along ~-
. . ~
line IV-IV of Figure 3. This figure of drawings there- :.::3.-.`.
::: ......
.. ..
....... ~
' :''.'.'
::::: .:
..........
.. - ...
~ .
1177697
. . ` .
fore shows one of the two normally hidden sides of lintel
assembly 12, namely the inner s~rface of lintel moulding
88, the longitudinal cross-section of lintel member 74
with its groove 76, and finally the lintel doorstop 99,
..........
which components terminate precisely in the same 45 degree
plane 100. Plane 100 and the corresponding 45 degree --
- - . .
plane at the opposite end (not shown) of lintel assembly
i....
12 are perpendicular to each other. L-shaped clip 90 has ---
. -.-.-.-..-....
its horizontal arm 92 properly seated and secured into
groove 76 by wood screw 94 while its downwardly extending
vertical arm 96 extends essentially perpendicularly to the
.. ....
outer main surface 102 of lintel member 74 but as close as
. ..
possible to the terminal end of groove 76. - -
A slit 104 or 106 is precut in the pointed ends -
. .-..
of the mouldings in order to facilitate insertion of a ~-
corner key 108 in order to maintain the outer edges of
r.. -
mouldings 40 and 86 or 42 and 88 in the same common plane. -
.:::. .:: .
On the construction site, the framing of a par- -
. ...
tition opening is easily accomplished using assemblies as
described above made in accordance with this invention. -
- - - ..
The first step consists of temporarily nailing lintel as-
..",.,.,:.,,
sembly 12 horizontally to stud 239 centrally of the open-
ing, by three or four small finishing nails. A level must -
be used in order to insure proper positioning of lintel -``
..... -.-
12. Then, side post assemblies 14 and 15 are inserted and
rotated to the vertical position. Starting with the hinge -
..... :~,.: ::
plate side post, for example side post assembly 15, this `~
assembly is guided in position by pushing its upper end
,.. ......
. .....
1~
~r
1177~69~
upwardly until proper engagemellt at the ~iter joint on ac-
count of the presence of L-shaped clip 90 already secured
in place to the corresponding end of lintel assembly 12. ......
A small wooden wedge acting between the floor and the .
.. .. ......
lower end (not sllown) of side post assembly 15 facilitates .-
temporary holding of side post assembly 15 in the exact -:.. -.-.. ~
vertical position (as verified with a level) while the
:::::::::::::
carpenter drives five or six small finishing nails through ....
''-:-:-'.-:'..-:::-''-'
the inner and outer mouldings into the underlying vertical .--
- .....
stud 21. The next operation consists of hanging the door ~
.. ......
to hinge side post assembly 15, to which the hinge plates
had been previously screwed, and then closing the door. .-~
,... .
Now, the strike plate side post assembly 14 is secured in -
........
place with a few nails through its mouldings 40, 42 once
. . :-..
it has been positioned as high as necessary to close the
miter end, and with its lower end equally spaced from the ~.-.
door panel 62 to leave a gap of even width between its --
..-.:...-. .-.-
main outer surface 32 and the adjacent edge of door panel -... -
--. . . :.
62. Finally, once it has been ascertained that this pre~
.. -.
liminary positioning of assemblies 12, 14 and 15 allows ...
free movement of door panel 62, the carpenter completes
the job by driving more nails through the inner and outer .-..... -.
.. ...
mouldings 40, 42, 86 and 88 and finally by inserting cor- ..
ner keys 108 in slots 104 and 106 at the top of both miter .......
.......
joints on each side of the door frame. --.--
-- -
It will be appreciated that this method of door .. -.`.
.-.........
framing does not require any shims between the vertical
and horizontal studs and the adjacent assemblies 12, 14, -.:.. :.--:.:-:
.. -
. -.- . ..--.-
.-.::.::.:
.-....-.
. . :- .
..:. :.. .
. .- - .
,, ~ .
117~69~
..... ..
. .- . .
and 15, and it should also be apparent that since the - -
miter ends of these assemblies have been precut at the -
point of manufacture to the exact dimension of the desired
door opening, the job of the carpenter on the construction
site is considerably simplified and only takes a few min- -
..........
utes. Moreover, the miter joints are necessarily very
accurate because every component of each assembly 12, 14 ---
:.. -.. :
and 15 was permanently secured prior to cutting at 45 de-
gree which can be accurately controlled when this opera-
tion is carried out with the use of standard industrial
tooling at the point of manufacture. ~-----
... .-.
It has been found that jamb members 30 and ---
lintel member 74, when made of green soft wood, tend to - -
warp sufficiently at their free ends (in spite of the --
presence of groove 70 and 76) that the ends of mouldings ~--
40, 42, 86 and 88 tend to gradually separate from the F-:-,,,,=,,
surface of plater board 25 as the wood of the door frame -
dries. Thus, in accordance with this invention, I provide
one cross-piece 120 at each miter end of every sub-assem-
bly 12, 14 and 15. It was soon realized that these cross-
.-.:.:-:-..-:::- .
pieces 120, one of which is shown in perspective view in
. . -
Figure 6, also serve to better retain L-shaped clips 90
....... : .
in place, and that they facilitate closing of the miters -`
during the framing operation. I use U-shaped steel cross-
pieces that are about as long as the width of the jambs
members, with two small holes 121, 122 for wood screws
(not shown). They are secured in place over the shallow --
groove 70 or 76 as close as possible to the adjacent
.
~3
1177~697
m~itered free end of the jamb ~ember, preferably at the
~oint of manufacture. Considering the force exerted by
the warping wood, which must be counteracted by these
cross-pieces 120, I prefer to use ~-shaped cross-pieces
.:.: ....
with slightly diverging flanges 124, 125 made of spring
steel but other shapes are obviously contemplated. The
_... ..
thickness of cross-pieces must be limited in view of the
restricted gap between hidden surface 34 of the jambs or --
lintel members and the outer wide surface of the adjacent
stùd 21, 22 or 23. There is no real need to put cross- -
pieces 120 elsewhere than at the miters. - -
-. . ..
Thus, the invention provides pre-cut, pre-
assembled channel-shaped framing assemblies which are
delivered in discrete form ready to be installed to the --
partition to be framed. The present kit of parts may of
course comprise a door panel with hinge plates and latch ~--
.
hardware in place or ready to be screwed in place if holes
and grooves had been made at the point of manufacture. --
The side part assemblies may also comprise grooves or - -
indentations and holes to facilitate mounting of the hinge
.-
plates and strike plates, although these accessories could -`
be installed at the point of manufacture. The door panel -
.
is not necessarily supplied with the knocked down frame -
assembly; in some cases no door panel is to be filled to
the framed doorway; in other cases, standard sized door
panels of accurately predetermined dimensions and charac- ~--
teristic may be selected which would be compatible with Y
such a combination of two side post assemblies and one
lintel assembly. - -
., -~
