Note: Descriptions are shown in the official language in which they were submitted.
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1
~ LOG CONSTRLICTIbN ~
',~'ECI~iNICAL FTELD '
~'rie present invention relates to lag construet.icn.
respite the advances in modern building construct~.on
techniques, the traditional log construction nonetheless
7Cel~~lnS papul~r,..~W tn itc ~RSthEat-ir flr~~iti01~,~1Ji~l~~ar8ll~e~____
________.
modern log buildings are commonly made in a prefabricated
fashibn at a factory site, end . thef: ~ .'.rl~.r~z=sw :.,~. t::o
destination.
The most dominant disadvantage to ldg construction is
that tile log tvt~lls tend to be drafty, paxticularly~due to long
term shrinkage and settling, which exposes gaps between the
log joints. As the shrinkage occurs, ttie log construction
2o tends to lose some structural integrity due to loosening
joints. Advances in packing Materials have made significant
advances, in reducing.. air . infilt-pat-io::. trrough. the. lcg-~~~all,
but problems still remain_
.... _ ~~ ~t is ~:: ,~",b~w"- oW *hw-pres4~~!:.. .~~=18r~.t~~w_v-
.w:~=:~~t~~:;=~ .:s~' _.__ ... ..._ ....
improved log construction techniques.
30 , Hriefly stated, the invention involves a ldg construction
cvmpzising:
a pair of Iogs, each having an end region with a surface
CA 02350851 2001-07-05
n~.f.3.5Gni mull ie..~.7..FaY Tne osnnn.,a L...,.... n n.,.,m., ~",..... inns
_ .. ..y rv1 aaW.r'as':VI asaaa Wiv"3~da:vvl--Y ........... yy,ru a~. -
.~,pGi<. " vvy ...
2 '
pOLtiou 4~r~i~4Tt; _-Wa"a2~~3n -'~.~s'_y~~f~.~ ~114~t~.~~..3ri?
.c'~rraFiC~Rfl_t_LL __
engage one anpther at a boundary therebetween, the boundary
havi::g a.l.$~~_gt5~y_....
at least one baxxier extending across the boundary .an~? . _.
along the length thereof to couple the end regions togethez~,
the barrier hav~.ng a pair of projections,
each Qf the logs further comprising a passage open to and
ad~aGet'1~. the boundary for receiving a Corresponding one of the
prO~ect10n5, ,
each of the projections having a pair of outer surfaces
and the passage having a pair of .'inner surfaces, the outer and
inner surfaces being fuY'thAr arranged to generate- rBSidual
compressive - fcirces- tofaard - the 't~oundary as a ~~ result Qf
shrinkage betsrseen the b.:::,°.;,.z~. s:.d t::.~_.-cad rog:ona-. -....
. -.. .. ... -
In another aspect of the present invention, there is - . ... . _ ..
provided a method cf ~cr:~i::g_.a .1~ _canstr~~ct,~.on .compri.six~g..t~e.
..._ _.....
steps of:
providing a pair of lags, each with an end region having
a surface portion thereon,
arranging the surface portions are arranged to engage one
another at a hout~~d t"a ~T~~h-°-rohof-~uoon ~ j-?ag. hrnlnd~lr~
_.halt'~nl~__a __ ______ . _
length,
prQ~i$ing at least one barrier to extending across the
boundary and along the length thereof to couple the end
regions together, the barrier having a pair of projections,
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forming in g8,ch of tk~e logs a passage opel'7 to and
ad~acent'the boundary for receiving a corresponding one of th8
projections,
forming on each of the projections a pair..of muter
surfaces and in thA passage a--pair-rf-inner_aurfaces;
arranging the out°r- an ~ i.~.:7eX surfa~':Pa tn nAnPrr~tc3
residual compre3sive ~CQxces toward the boundary as ~, r e-sult-of- ---
shrinkage between the Y~arria7~' a»ti trie en~t regxot~s.
BRIEF DESCRIPTION OF TI3E DRAB rW NG5
,:
Several preferred embodiments of the present invention
will now be described, by way of example only, with reference
to tt~e appended drawing's in which:
figure ~, is a perspective assembly view of a log
construction;
Figure 2 is a fragmentary plan view of the lag
construction of figure 1;
Figure 3 1.S a TA8'I'ii~;e~ ~~~r~Te'~f~Taa~y p~~Sp=~'~'~:ai a~~x~wif _..._ .
..._.
view 4f one portion of the lag construction Qf figure i;
Figure ~ is a magnified fragmentary plan view of a
portion of the log construction of figure l;
,Figure 4a and 4b are magnified fragmentary plan views of
other l~C~ C6nStrzlotibns
Figure 5 is a magnified fragmentary schematic plan view
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4
of the log construction of figure 4;
Figure & is a magnified fragmentary schematic plan view
of another log- ,
k'j~gure 7 is a fragmentary assembly view Qf still another
log constYUCt1011: .. _ __. ..
_ _ . _ .__.Fsgurp .8 is-a_.fr .agmpntar~r._x~c~r~;pective view of yet another
1~ 1CCJ CC~Stiiiv:vivW i
Figure 9 is a fragmentary plan view of yet anotheY log
Construction; ,
15 F~.gure l0 i,$ a sectional view taken on line 10-10 of
figure
zo
Figure 11 is a fragmentary $ssembly side view of yet
another log construction: and '
Figure z2 is a fragmentary sectional view taken on line
12-12 of figur~ 11.
,BEST MOLE FOR CARRYI13 QUT TH,~",_ItIVF.I!lTION ____
deferring to the figures, there is provi a a og
construction 10 comQrising a pair a= Wogs -zi, -i3, each -iog ~ w ~ -- ~-
having an end region 12a, 14a formed to engage one another,
for example by a rectangular joint. uhe iog~ have
first surface portions 12b, 14b an3 adjacent .~ocond suxfa~ -... .... .
portions 12c, l,øa, each with a length 'W' betwee;, a;, S,u~$i w
surface 12d, 14d anc3 an a.~.~~r~:Yd:.ate °~;rfac° 22e, '19e. hs
seen in figure 2, the surface portions are, when assembled,
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separated by 8 boundary 7.5, and az~e preferably upright and
planar_ Iri this case, the boundary is shown to involve a large
gap for illustrative purposes only.
5 The end regions further comprise first barrier receiving
passages lzf, 14f adjacent the first surface portions and
____ _ ____ __~eCS~Ild 17~~r~p?'' .ro~pivi nn na~saoes 120. 14u whiOh arB Open
t0
and adjacent the second ss~rface portions and the boundary in
their
A rigid ba~;wzer~ i~ the fax". ol' s kcy ls., ...~ pr o~:ided to
engage each pair of aligned passages 1 2f , 14f and ~ gig, ~ ag, tn
interrupt the boundary between the adjacent surface portions
along substantially the entire length thereof, thereby to
couple thg er~d rggiotts together.
Preferably, the key has a tensile strength, shear
~.:~~.. 4r,,H~h~t ~~::~i~sn anA ~t~°t~~:i,~n
. ..... .... _ -rQ3~~,y~,T~ ~,y th~ -.~,~?.~~;y~. ,3"ie.~-~~'~r~'~ ~t rn~_'
nnrc accnmt,~nr~
,. ... .. ..... .... ,.... .. _...._. ._.........._.._.__...,
zo the key also has the capacity to inhibit displacement of one
surface portion relative to its aGl,jacent surface portion,
thereby inhibiting relative movement of the logs, that is to
inhibit displacement of one surface portion relative to
another transverse -to the baun~ary. ~iW a ~deg~.ee ~ to ~ which the
~ 5 key wi 11 inhibit such relative mover~ar~ ~ ~ ~ d~Fer~ds~ ~ ~o~ w~t5w ~ -f
i
between the key and the aligned passages.
each of the key receiving passages incluaes a bear~ihg
surface 12h, 14h, to establish a loaded r._n.~,~.i.t,'_nn w;tr,_ the
3o barrier. zn this manner, each of the bearing surfaces of one
passage, has a corresponding opposed bearing surface in the
other barrier receiving passage. Thxs can be seen in figure
9 wherein the, bear] ng fiua~.t'a.~.4a. , ~h .~'. n.. ~ ~.. _,_~_:~.re_ >a.,
_i ~r.~.rl::~i ~-~,..__ , . _..____ __ . _...
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6
the opposed passages 14h in lag 14.
~rho outer surf~rps Of the prQiectfons and the
correspotiaing inner surraces-o~'-tneages -dre ~c.ompiaraantary
and are further arranged to generate residual compressive
forces toward the boundary as a result of' shrinkage between
the barrier and the end regions, thereby to establish this
compressive loading_ Further, the keys and their
corresponding passages rnay be configured to establish tensile
loading on the key and consequently compressive loading on th~a
bearing suxfaees in ordef to have the effect of drawing the
logs together, that is to minimize the spacing between the
surface portions at the boundary 15. Therefore,'~~t is-ta:.stla
strength and stiffness should be sufficient to withstand these
35 forces.
The ltey 16 has a pair of aligned webs 16a, 16b, each
shaped to fit snugly with~.n a corresponding one of the barrier
receiving passages (though a loos$ fitting is shown for
2~ illustrative purposes). Tk~e webs 18a, 16b are also joined by
a central. portion ~.6e to extend across the boundary 15. Each
of the projccti.oxls j,r~cludes a pair of bearing surface portions
16d, l6e.for engaging a corresponding bearing surface in the
b$rrier receiving passage.
Preferably, the projections arc symmetrically arranged
along the comm~7zz cpntra~ axiS_.'_A~_,,. ,The outer surfaces of each
of the prnecaic~nx rliv~erge from the boundary relative to the _
axis. More prefers y, i m
34 Grv~:~-- ccctic~r, ---fir - ~ha- -r~d'g~=-shaYs,-d'. _. .:.1-;: a-r-~zst-
ia~r. ... .__..
embodiment, as shown in figure 4a, the Central portion has
parallel opposing side f$nes 17a and the outer cor5ters are
rounded as shown at 17b, 17c. In still another embodiment,
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7
the projection has circular divergent outer surfaces ~.9a, 19b
as shown in figure 4b. The log construction can also utzli2e
a number of known log joinexy _tpchnigues,.suck~ as a dove tail
joint as shown iri figure 7, which also makes use of a central
portion with parallel Opposing side faces as shown at zl.
A particular feature of the log construction is that the
barrier and the logs may be formed from materials with
different "coefficients of shrinkage", a terra which is
1o intended to refer td the degree to which a part~,cular material
shrinks over a predetermined period of time and may be
expressed by some ratio of the 'pre-shrink~ length and the
'post-shrunk' length of a unzt sample of the material. For
example, green softws~od _suGh as pine--caw sp-rwe~ -sh~uid- shr~.~sk
to a greater extent (and ther4fGre have a correspondingly
higher coefficient of shrinkage) than a green hardwood, and to
a much greater. extent than a substantially cu~esl. h~.rdwood-. as
one might obtain after an appropria'~e period of kiln or air
drying, fcxr -exa~ap~e.
. . . Preferably, the barrier find Liie icicj5 isi~ i~tii Furm~sClwTt'C~h~-__
. ___ ____
wood materials, while the barrier is formed from material with
a lower .shrinkage coefficient than the material_.of. ttae lotrs..
Still more preferably, the baxrier is farmed fxom hardwadd
z5 materials arid the logs are formed from saftwood materials.
More particularly, the barrier is formed from a single piece
of substantially cured haz~dwdod and the softwood material is
green.
. Conveniently, the barrier and the passages are
dimensioned so that the barrier c811 17e i11st811ed i11 place by
slidable engaging the barrier with - 4 :e y .ra~sSag~S -dtti'ing- ~ ----
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8
assembly.
5uxprisingly, the compressive farces arising between the
barrier and its associated end region from the natural effects
of ehr~.nkago rnay ba r~i rected to draw the end regions , so ,-
c~aun7ed into tighter engagement without the need for .
additional locking or wedging - iiat~i3wara . -' :,s-- ear. ba' seen in ----.
. . -
figure 5, the green softzaood of the end region tends to shrinfc
aver time, thereby making the passage smellGr ~in 4Lo3~
to secti.Qna1 area shown by the chain d4tted lines, that is it has
a relatively high coefficient of shrinkage. aecause the
barrier itself, in this particular examp7.e, is made from a
substantial~y 4tzrs~? i~ar, i.t shssu3.s3 net s~irin~ ~.~a t~nu
measurable degrcc and ~_1'iex-~fwr'a.whas -a-.sign.ificantl.y_ ~na_ll.ax'- __-
.___ __
coefficient of shrinkage. The barrier, as a result, will
become more tightly engaged within the passage as it reduces
in size, thereby causing, in eftecG, a sgueezing action an the
barrier.
~. particular aspect here is the arrangeiaent of the inner
and outer surfaces which, though sxmmetrical re7.~3~i..e _ta the
common cent7cal axis ~A~, the surfaces are not symmetrical.
about a central transverse axis shown ~H~, as miyiiL utuerwise
occur if the cross section of the pro jection were, for example _
symmeJtrically oiroular or ellipsoid i-n cross section, as shown
d. LL... ..l G-~-.-._~_ ._ xvwl. A
in ~~gure n. iYl a~'lTl~.3~ iaic~~u5, v.~,tra v.W;yi:~maiv.~ ~.~~._.~a
~::~~w~.--- .-_.._ - ._..
Qn a circular_ .pr~~~.rf-..inn by .itS corresponding passage on one
side of the tr~n~yPrrr~ apr_i_s; ~rnulrl.nal~ance_themsel~e~s~~_With,
. .. v is " i'visay~ -..~~ __ 4 hg._ ~p~~~~- ~i~aLr-~~. .. ~f;~.--
.~~g~~r.o_~~a .- ~av.~c.~.. _
3o resulting in substantially no residual forces emerging
therefrom.
In thQ case of the embodiment of figure 5, tk~e
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9
~~r~.QSSi~re_ fnrl~.,P~. F~. on cane side of the transverse axis -do w
rat balance those on the other side and infect they reinforce--
. one another and - tYii~ resultir,t~ residual iarc:e i.y uitacta.:
toward the boundaz~y and has the effect of drawing both etW
regions inwardly to~tard one anc~iier at '~ is b~uu~'~.W.~X
residual force is generated between ~11G 5U11G~rv.7 w aiGi u~~-
arrar~ged in a divergent manner away from thg opening t4 the
hc~nndary, and in the .Cash ,df the ~rian~ular., crass section,
..larve -i-ruw~-~rrespo :ding ~eaevorg~rs~..~s:~;face~. Lbw--~ecsfu'~d-
wthc~r~:.~i-se -.. ... .._. _.. __
1o balance to creat8 a substantially zero residual force relative
to the commc_,1r't rpntral. axis. Thus, the outer surfaces are
asymmetrically arranged relative to the transverse axis_ The
residual forces therefore are caused by the compressive ~L"_"n°_~.....
F~ generated at the intersect~.on of ttte inner and outer
~,5 surfaces and more particularly to the component thereof in the
direction of the common central axis, as shown at Fp,, and FRK-
In qther words, the force FR,, ~ten~~s-tn fnrr~.c~ the 8nd YAtJ10Y1
toward the boundary while the force F.,~ t.ends to force the key
away from the boundary, the net effect being biasing of the
2o end regions together to minimize the spacing therebetween at
the boundary and to form a s1~~ug o3:~nco~i-on-~t:~.or;.b.ot:~.:.~:;-:._._ -Tn
_- _ ..... .
order to provide these compressive forces, the angle of the
inner surface of the passages may be at an angle a ranging
from 45 to 85 degrees aT!d mcar-~ _.~lxa~'e~ak~.x about 8a decrees..
It will be understood, finer the wurfaces may come im avy
_ - number-.._4r...-d~.Ff ~ ~ _ ~a_a ~,...~ A~..;
e7."~i'fW ..CO~tiil~L4:,-~rL,.SrJS~a-, -~JS~~-YT's'.
arranged in a similar manner as alcove.
. The joining technique shc~~az,. ?ere-in_~.ho-v~_ ~s_iaar~irulax:i,;w.-
useful because it is simple to in~all- a..~.d requires . no _ -
additional tightening manoeuvres With additional wedging
dBVic:eS. R:vths~Y _~ ,__ ,, :.f t: c
the preaerrt t~~ ~..~y4G lItUJlO.-i ~G
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..._....... ..__ ~nm
natural compressive forces caused by the natural shrinkage of
the materials. The same technique can be used to form butt
joints and corner joints in the same log construction thereby
reducing the number of parts necessary for a p~~e~lar
5 Constructibn. __
The length of the keys depends an the length ~W', which
of course will depend on the thickness of the logs and the
prO~l.le bf tiJC kJ$t1'~i~i.iia~ ~VI~~t pwttcr:: read, the i ntPntion
1D boring that the key Pxtends, t$e grltire length 'W'. Ay ..
extending the entire length, the key can provide an effective
t+ +1, i .,~i'1 tra~i nn ref A 1 Y thrnllf~h. 'thfa 1 nor wall
barrier again.. .~..c _.. . -
as would otherwise occur through the boundary as~shown by the
arrows in figure 3.
. .. Hi~i~Y~Vc3f , i.~rie iii tii.'c lGugth . u3jt : 1°~ ~'° ~-
r~r,-~ad r,;~ :nnr n
than one single barrier. The single barrier maybe replaced
wa.th, for example, three keys, all with a ocllective length ..
equalling that of the single hey as..shown at ale, b, c in
2o figure 7.
The_ log construction may ba torrned in the following
mantte~-. First, the lags 12, 14 are cut to length and their
end regions are shaped so as to engage in a complementary
fashion as shown above. The barri$r receiving passages ii=,
14~, 1~C1, leg are rClrmeQ 60 LFIdL t17~'~y fC7CL'4'ilU J.L~VIII I.iJC
V~U4kt~~ ' '---- -"
surface 12d, 14d tQ the intermediate surface 122, 14e. The
keys are then formed with a cross section which is
complementary t4 that of the aligned passages.
The- keys Andy -b
the axis 'A' in order to immediately establish ~a loaded
condition w~.th the bearing surfaces. With the lags in their
CA 02350851 2001-07-05
9i~-n?.ini T_r_n_r og;gn Fax_ ~n, n~2nn-~ _ . _ . ,rA,~~~ F..,. ra:st2r .....
...._..... . ..._....... ... ....f~t.nl~
11
position with the passages aligned, the keys may then be
pressed--~:~ -Nl~ce- :ait::...apprrpra.at..e-~u,7_ki ng compounds placed
therein as necessary. The joint may then be~ 3eft Lo rise
forces cf- ~at:~=w y:: b~i~xl ~~~~ ~'"=nk~~..of_t-_,hp. ma.teri,als..._.._.
_.. __._ .
s to establish the residual farces as described.
The cross sections used herein have the additional
benefit of increasing the engaged surface area of the =nnpr
and outer surfaces, both to increase the area which is
.1.... 1.5.~.~.....s nw
available far caulking materials, if desire..., c. ~,. c~........~....
increase the distance. that infiltrating air would need to
travel to cirouyrrvent the barrier so formed.
,.
the key may, if desired, by dimensioned to extend beyond
a s~.ngi~ .~Qi:~t. For cx::.~,pl s, the key s may extend t,Ryr~nc3 two
or mere joint$ as shown in the log construetiQn 30 shown in
f;.g~r~ e. ~ I~ tYris ~ca~c, -there -$=s pr~v~.decL rwo_ ~t.s ~.f_~ng.~ __.._
.. 1?,...3.~ ,...r,~.itV~._ easch .spt_n2~~!?g a n~smhsr .,f alihnp~l end
rPrri nns
32a, 34a, with each log element from set 3z formed to engage
$ pair of adjacent logs in set 34. There is provided a series
of first surface portions as shown at 32b, and a series of
second sctrfaGe portions as shown at 32c. _ _, _. _
In this case, each log is also provided with barrier
__. .... . . _ ..3G ....=aasit>.i.y~...pp~s3gos._33s. ~-33L~r_E~!~..~ .of. whi
ch extends the full
thickness of the log so that, when assembled as Shown in
figure ~, the passages 33a, 33b align togettr~~- i=c,s l~rrm- a
substantially continuous e~.ongate passage extending the full
length of the so-formed log 'wa7.1' . This is shown in the case
of the passag~2s 33a by the dashed lines at "33A".
A pair of keys 36, 38 engage the elongate passage 33a,
33b, thereby to interrupt the boundaxy between the adjacent
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12
surface portions and to inhibit relative movement between the
~.og elements of each set of logs in the cc~nstruction,~ __. . __ .
The keys used herein may be formed from a number of
materials- Hardwood materials such as maple and vak are
readily available and provide a natural cauntex~pax~t to the
softwoods normally used for the logs themselves.
lIowevor, other raatoxiala ouch as plastics are also _
to envisioned. in this ease, the materials may be prefarmed into
the keys as shown above or alternatively be arranged to be
forced in a liquid or athEF de~rmabls consistency, into the
aligned passages. 'this technique has the advantage that__rh~.
key farming material can fill the voids in the aligned
passage, while accammadating minor misalignments between the
logs. Furthermore, the passages can be finished in such a
manner to allow the key forming material to partially ai" fully
extend beyond the passages themselves and fill the spacing the
between the adjacent surface portions. mhe key forming
material, in this case, may be a thex-moset material syGh as
those defined as epoxies or thermoplastics such as
~n1 ~r~a~~vlpna nr nnl vnrnnyl Rna _ ~rhc~ rhararrtwr i ut W -c c~T W hp_ - w
formed key may also he modified by adjusting the make up of
the material., for example by adding a reinforcing fibre and
the like.
.._.. ... _ .. ..__ .... .. ....~7'~ ferri-ii(y w fi~jurar.. ~, +~'~'~'~ 3.~.
Yes.".': i~°~ .,°."'°*~'.~..~ 1 r"~r
..a.a .. ~. ...w. ..... ~..
construction
complement-asry. Pnd _rggin>tsv_57a; _54a. _ __.In thls case;__.the
complementary end regions are simply a fla'r.~2nd face to farm
a t~uLL juinL having a lc~ansverse boundary a6. ,A barrier in
the form of a key 58 is arranged in a like fashion to that
shown above.to interrupt the haundary along substantially the
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13
entire transverse dimension thereof, in this case, the height
as ahcwn' in figurE 10. _- . _ ._
Referring to figures 11 and 12, there is ~7rovided still
another log constructio~ ?~. with a p?~ir of_ i ngs ~2 ; ?4 having
complementary end regio::..._;~~a~ ?4a....- IrL_th;~ r:asp,__~he___. ____
E:c.~tupltamtsmtaty end ~egiolr» Ax's Simply a flat end face to f4rm _
a butt joint having a transverse boundary 76. one end face has
a projection lab and tk~e othex end face has a complementary
recess ?2b. A Pair ~h rest-an4rrg._esse~tk~li~aa--:,°.- ire ~rovi-dcci--
to -_
engage each of the end regions on opposite sides thereof.
each of the fastening assemblies includes a pa),r of
cylindrical plugs 80 mounted on a .base plate ~2, eaah plug
adapted to receive a fastener such as a spike 94, by wax of a
sma~.~. e7.ongate passage or the like. A pair of passages ex~.end
through each of the end regions ?2a, 74a and are dimensioned
so as to receive a corresponding pair of plugs as shown.
The spikes are dimensioned to that 'they can be driven
through the upper' plug a?ld.-n~r~Pnt i f,LO Tw - i'ow .r i ~ r~ ' ~Prely~r
°'
to hold the fastening arse~nblies in place. The plugs are
firmly mounted on the plate sv that the plate can absorb the
loading 'exerted thereon should the butt end joint:-' If '
desired, the plugs may be dimensioned to ext~and fully into the
_ . ... 1~ ~~~~g~~ .~.~y.~~p~ ~~.~ '~o~~.. a~ siic~wn in un5ii~u iii»b iii
figure 12.
