Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to the butt jointing of structural
members in the nature of wooden logs used in the construction of
a log cabin.
In the building of log cabins, logs having a thickness
of six to ten inches are laid one over the other to form the walls
of the cabin. It is seldom that a single log will be long enough
to form a full length of the wall of which it is a part, and there
is a necessity in log cabin construction to provide a means for
joining the ends of the logs. The traditional method is to have
the ends of all logs in a wall terminate at the same location in
the wall and to overlap the ends of joined logs that constitute
the length of the wall. The overlapping logs are bolted together.
This practice is wasteful because all logs do not start out by
being the same length, but must be cut to a common length. Methods
for avoiding this waste wherein the logs are joined at their ends
wherever the ends should occur having regard to the original
length of the log, have been proposed. Joining logs in this way
involves a butt joint and the sealing of the joint. Various
sealing methods have been devised for sealing the ends of logs
so butted in the side of a building. They are an improvement over
the traditional method because they save lumber. However, those
methods of which I am aware leave considerable to be desired from
the point of view of providing an air tight strong butted joint
that can be easily and quickly assembled.
This invention achieves an air tight strong butted joint
for two abutting logs that can be easily and quickly assembled and
that can be economically manufactured. It is an object of this
invention to provide a butted joint having these characteristics
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and also to provide an accurate and efficient method for preform-
ing the surfaces of the logs to be butt jointed.
According to this invention butt jointable structural
members each have a butting surface disposable in abutting relation
with the butting surface of the other; a channel with an opening
and with Gpposed side walls that diverge and extend across the
butting surface of each structural member, the openings of the
channels of the butting surfaces facing each other with the longi-
tudinal axes of the channels in parallel relation when the members
are in abutting relation; a pair of cooperating locking members
each having a longitudinally extending locking surface that is
complementary to a portion of the side wall of the channel of each
structural member adjacent the openings of the channels when the
structural members are in abutting relation; and wedge members
wedgeable between the locking members to force the locking surfaces
thereof apart and into close locking relation with the sides of
the channels of the structural members to maintain the structural
members in abutting relation.
The joint involves the formation of an open channel in
the butting surface of a log and the method for forming structural
members to be joined in locked butting relation according to this
invention comprises the steps of projecting the member along a
predetermined path having a direction at right angles to the dir-
ection of the open channel to be formed therein; stopping the
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member at a predetermined location on the path and clamping it at
the location where it is stopped to dispose the butting surface
of the member in predetermined location on the path of travel of
the member; moving a drill along a drill path that is predetermined
in relation to the predetermined location where said member was
stopped as aforesaid, and that is at right angles to the butting
surface of the member stopped as aforesaid, and that will carry
the drill to bore an open channel in the butting surface of said
stopped member; unclamping the member and continuing the member
along and beyond said predetermined path. The invention will be
clearly understood after reference to the following detailed
specification read in conjunction with the drawings.
In the drawings:
Figure 1 is a partial illustration of apparatus used to
form logs with a channel for incorporation into a butted joint
according to the invention;
Figure 2 is an illustration along the line 2-2 of
Figure l;
Figure 3 is an illustration of two logs end butted to-
gether with locking members and wedge pins for insertion into thechannels;
Figure 4 is a top view of two logs joined together at
their butting surfaces;
Figure 5 is an illustration along the line 5-5 of Figure
4;
Figure 6 is an illustration of logs butted at right angles
to each other; and
Figure 7 is an illustration of a log building where the
butted joint of this invention is useful.
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Referring to the drawings and at first to Figure 7 which
illustrates a log building the sides of which are made from milled
logs similar to the milled logs illustrated in the drawings of
this application. These logs are joined at their corners by a
corner joint. The logs which go into the building are of various
lengths and are butt jointed where they meet in the side of the
building as indicated by the vertical lines 10 in Figure 7. The
joining of logs at the ends where they meet in the side of a build-
ing as illustrated in Figure 7 is an important contemplated use of
this invention but it is not intended that the invention be restrict-
ed to that particular use. It has application wherever logs or
the like are butt jointed and among other applications includes
the butt jointing of the end of a log to the side of a log as
illustrated in Figure 6 of the drawings of this application.
The logs illustrated in this application are formed from
wood and have their upper edges 12 and lower edges 14 formed with
a tongue-and-groove configuration for convenient interlock as
they are built into the wall of a building or the like. They are
commonly 6 to 8 inches in thickness and as previously indicated
in this application are butt jointed at their ends in the side
wall of a building.
Reference will be made to Figure 3 wherein the ends of
two logs 16 and 18 are illustrated with their end butting surfaces
disposed in abutting relation. Each of the butting surfaces is
formed with an open channel 20 and 22 respectively. These channels
are formed by a drilling operation as will be explained later.
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It will be noted that the side walls of each of the channels div-
erge from each other from the channel opening that extends across
the hutting end surface of the logs. It is the divergence of the
side walls that, in use, achieves the locking relation between
the joined logs as will be explained later.
The openings in the channels 20 and 22 align with each
other as is apparent from Figures 3 and 4 and, in use, a pair of
locking members 24 and 26 are inserted into the channels. These
locking members have curved surfaces 54 and 56 that are complemen-
tary to a side wall of each of the channels 20 and 22. They areof a dimension that they can be losely inserted into the aligned
channels with a reasonable amount of clearance between their sur-
faces 54 and 56 and the side walls of the channels. Once inserted
wedging spikes 32 are driven into the aligned channels in the op-
posed surfaces of the locking members to spread them apart and
force the complementary formed walls 54 and 56 of the locking
members into tight relationship with the side walls of the channel.
The butting surfaces of the locking members are spaced apart so
that as they are tightened into the channels of the members 16
and 18 they draw the butting surfaces of the logs tightly together
as illustrated in Figures 4 and 5.
It will be apparent that logs joined as described here-
in are locked securely together and that the securement is easily
and quickly achieved without the requirement of fitting skill on
behalf of the assembling mechanic.
The locking members 24 and 26 are preferably milled from
wood and it will be noted that they are formed at their lower ends
to conform to the shape of the tongue and groove formation at the
edge of the log below and that their upper ends are flush with the groove
of the log they enter.
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The open channels of the logs are preferably formed with
machinery that is capable of transporting the log to a predetermined
position where it is clamped and drilled. The conveying, clamping
and drilling operation are inter related for the handling of logs
that are used in a log type building of the nature illustrated in
Figure 7.
Figure 2 shows a portion of a conveyor 34 for a log
which has a back guide 37 to positively locate the log and deter-
mine the path upon which it is projected towards the drill 38.
It will be appreciated that only a portion of the conveyor is shown
and that in practice the conveyor will be of a length well able :
to support the largest log that is used in a building such as the
building illustrated in Figure 7.
The logs 16 are projected along the conveyor and are
arrested in the path by means of a stop member 36 which is located
on the bench by an operator as required. Stop member 36 is locat-
ed to stop the log so that its end butting surface will be engaged
by the drill bit of the drill 38 as the drill bit is moved in its
path of movement which is at right angles to the path of movement
of the log along the conveyor 34.
When the log has reached the stop member 36 it is clamped
into position by means of the hydraulicly operated clamp 39. Clamp
39, it will be noted, is mounted on shaft 40 which is caused to
rotate to move the clamping members from the position illustrated
in Figure l to the position illustrated in Figure 2 through the
operation of the hydraulic cylinder 42 and the crank arm 44.
Once clamped the drill 38 is reciprocated in its path to
cause the drill to drill the channel in the end of the clamped log.
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Figure 2 illustrates a drill in its most extended position.
After the drill has been operated to form a channel 20
in log 16 the drill is stopped from rotation and withdrawn. The
log is unclamped, the stop member 36 is removed and the log is
moved forward for removal from the conveyor.
The mating log is then drilled in a similar fashion, but
in this case the log is stopped as it is moved from the opposite
direction so that the opposite abutting face can be drilled. It
will require a differently located stop.
The logs so drilled, one after the other, are joined
in use. Preferably they are marked at the time of drilling so that
when it comes time for assembly and joining logs that are drilled
sequentially are joined together. A two inch diameter drill is
a satisfactory size for a six inch thick log.
Figure 6 illustrates logs joined together wherein the
butting surfaces are an end surface of one log and a side surface
of another log. In this case it is necessary to form the channel
in the side surface of the log 46. This is achieved by appropriately
stopping the log as explained above and cperating a drill similar
to the drill 38, but disposed to drill a hole in the top surface
of the log to form the channel 48 which in function is similar to
the channels drilled in the ends of the logs previously described.
Drill 50 is adjustable as to height to drill logs of
different depth and to drill the side surfaces of logs as for the
joint of Figure 6. Detailed reference to the mounting of the drill
is not made. It is a matter of mechanical skill to mount a drill
with vertical adjustment to drill a log stopped in a predetermined
location as described.
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It is preferable that the locking members 26 and 28
should flex about the common central axis of the channels 20 and
22 when they are in abutting relation. This permits flexing to
achieve ready and close cooperation of the complementary surfaces
of the locking members and channels as the wedges 32 are driven
into place. With a wooden locking member the flexing and strength
is achieved by having the grain of the wood generally at right
angles to the longitudinal axis of the locking members. The grain
in this general direction is indicated by the numeral 52 on Figure
4. It also adds strength to the locking members against splitting.
If the grain were to run longitudinally of the locking members and
be in general alignment with the direction of the spike wedging
members the wedging force of the spikes would tend to split the
locking members.
The portion of the locking members which achieve the lock-
ing action which, in use, pulls the two structural members 16 and
18 together as the wedges are driven into place are the locking
surface portions 28 and 30 which are complementary to the portions
of the side wall of the channels of the structural members adjacent
the openings of the channels when the structural members are in
abutting relation as indicated in Figure 4. It will be apparent
that as the wedge members are driven between the locking members
they spread and these portions 54 and 56 engage with their corres-
ponding complementary portions of the channels in the structural
members to exert a force that will draw the members together due
to the shape of the channels at their openings, i.e. the opposed
side walls that diverge in cross section. It will be noted that
the portions of the locking members that are at the bottom of the
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channels have been cut off to avoid any possible spreading action
of the logs by the locking members.
It will be apparent that when the locking members are in
place and extend for substantially the full length of the channel
they form a block to the free passage of air across the butting
surfaces. Preferably the locking members are formed with a longi-
tudinally extending groove as indicated at the numeral 28 between
the portions thereof that lock with the channels which is designed
to receive a sealant. Numeral 30 also refers to a similar sealant
channel.
Embodiments of the invention other than the one illustrat-
ed will be apparent to those skilled in the art. The joint can
be used anywhere where there is a requirement to butt to wooden
or similar surfaces. The invention has been described in relation
to wood but it will be appreciated that it could be applied to
materials such as substitutes for wood or any other materials where
the joint configuration is useful.
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