Title:
APPARATUS FOR GROOVING LOGS
United States Patent 3802474
Abstract:
Apparatus for grooving logs transversely to make saddle cuts for use at corners of log cabin. Apparatus has frame having upper longitudinal rail and spaced parallel transverse rails, a cut-off saw mounted on arm of cut-off saw carriage, the carriage being moveable along the upper rail, the arm being journalled to swing about the upper rail. A hole saw, carried in a hole saw carriage mounted on the transverse rails can be moved axially and has a stroke dependent on carriage travel. Log to be grooved is carried in log support disposed so as to be intersected by arc described by cut-off saw as arm swings, and to be within stroke of the hole saw.
US Patent References:
Cutting attachment for tube-forming machines
Roland - April 1922 - 1413191
Grooving machine
Crouse - July 1925 - 1547096
Log-and carriage-locking swingingsaw sawmill
Lambert - March 1948 - 2438610
Log gaining machine
Fowler - March 1955 - 2705031
Cutting attachment for tube-forming machines
Roland - April 1922 - 1413191
Grooving machine
Crouse - July 1925 - 1547096
Log-and carriage-locking swingingsaw sawmill
Lambert - March 1948 - 2438610
Log gaining machine
Fowler - March 1955 - 2705031
Application Number:
05/313943
Publication Date:
04/09/1974
Filing Date:
12/11/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
83/318, 144/2.100, 144/242.100, 144/4.100, 83/490
International Classes:
B27B5/00; B27B5/12; B27C5/00
Field of Search:
144/133,2R,242R,246R 83/563,591,613,824,825,411.7,745,403.1,435.1,706,318,319 30/390
Primary Examiner:
Juhasz, Andrew R.
Assistant Examiner:
Bray W. D.
Attorney, Agent or Firm:
Wood, Brian Jones Owen J. J.
Claims:
I claim
1. Apparatus for grooving logs transversely, the apparatus having:
2. Apparatus as claimed in claim 1 wherein the rolling means of the cut-off saw carriage includes:
3. Apparatus as claimed in claim 2 in which the rolling means of the cut-off saw carriage includes:
4. Apparatus as claimed in claim 3 in which:
5. Apparatus as claimed in claim 3 in which:
6. Apparatus as claimed in claim 3 in which:
7. Apparatus as claimed in claim 1 further including:
8. Apparatus as claimed in claim 1 in which the hole saw carriage includes:
9. Apparatus as claimed in claim 8 in which:
10. Apparatus as claimed in claim 7 in which the apparatus is adapted to cut a groove in a log having a radial slot extending inwards from an outer surface of the log, the log being carried on an upper surface of the log support so that the slot is normal to the surface of the log support, the guide means including:
1. Apparatus for grooving logs transversely, the apparatus having:
2. Apparatus as claimed in claim 1 wherein the rolling means of the cut-off saw carriage includes:
3. Apparatus as claimed in claim 2 in which the rolling means of the cut-off saw carriage includes:
4. Apparatus as claimed in claim 3 in which:
5. Apparatus as claimed in claim 3 in which:
6. Apparatus as claimed in claim 3 in which:
7. Apparatus as claimed in claim 1 further including:
8. Apparatus as claimed in claim 1 in which the hole saw carriage includes:
9. Apparatus as claimed in claim 8 in which:
10. Apparatus as claimed in claim 7 in which the apparatus is adapted to cut a groove in a log having a radial slot extending inwards from an outer surface of the log, the log being carried on an upper surface of the log support so that the slot is normal to the surface of the log support, the guide means including:
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus for cutting a transverse groove to form a saddle cut in a log for use in log cabin construction.
2. Prior Art
Traditionally log cabins were made of logs cut to length, the logs having a saddle cut near each end. At a cabin corner, logs in one wall are staggered between logs in adjacent walls, a saddle cut in one log engaging a respective lower log. The logs used were rough logs, or sometimes debarked, and the saddle cuts were often made with an axe, and such method of construction produced gaps between adjacent logs and ill fitting corners.
It is well known to turn a rough log in a lathe to produce a turned log having a cylindrical outer surface, such turned logs permitting a more accurate cabin construction with reduction of gaps between adjacent logs. Construction with such logs would benefit by providing logs with saddle cuts complementary to an engaging log.
SUMMARY OF THE INVENTION
The invention reduces difficulties of the prior art by providing an apparatus to produce the saddle cuts at ends of logs. This machine can be used with rough logs, but best results are obtained with cylindrically turned logs. A hole saw having a diameter equal approximately to diameter of the logs cuts the saddle cut, and thus essentially uniform complementary contact is obtained between a saddle face of the saddle cut and an adjacent lower log engaged by the saddle cut.
One embodiment of the apparatus has a frame having an upper longitudinal rail and a pair of spaced parallel transverse rails extending transversely across the frame. A cut-off saw carriage mounted with rolling means for movement on the upper rail has an arm journalled to swing about the upper rail. A cut-off saw is mounted on the arm so that swinging of the arm causes the cut-off saw to describe an arc. A hole saw carriage carries the hole saw powered for rotation about a hole saw axis, the carriage mounted on the spaced rails for axial movement of the hole saw, which has a stroke dependent on carriage travel. A log to be grooved is supported and disposed so as to be intersected by the arc described by the cut-off saw as the arm swings, and to be within stroke of the hole saw. Thus movement of the hole saw through the log cuts a transverse groove across the log and swinging of the arm severs the log to cut the log to length.
A detailed description following, related to drawings, describes one embodiment of the invention which however is capable of expression in structure other than that particularly described and illustrated.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified side elevation of an apparatus for grooving logs according to the invention,
FIG. 2 is a simplified front elevation of the apparatus of FIG. 1,
FIG. 3 is a simplified fragmented detail of a portion of a cut-off saw carriage,
FIG. 4 is a simplified fragmented section on 4--4 of FIG. 3.
DETAILED DISCLOSURE
FIGS. 1 and 2
An apparatus 10 according to the invention has a frame 11 having two spaced vertical triangular side frames 13 and 14 joined at upper ends by a longitudinal upper rail 15, and at lower ends by spaced horizontal members 16 and 17. Spaced parallel transverse rails 18 and 19 are secured to the members 16 and 17 and extend transversely from front to back of the frame. A log support means 20, such as a roller conveyor as shown, carries a log 21 which is to be cut to length and provided with saddle cuts.
A hole saw carriage 22 is mounted on wheels severally 23, which wheels run on the rails 18 and 19 so that the hole saw carriage can traverse forwardly in a direction shown by an arrow 24 to produce a saddle cut in the log 21 as will be explained. The carriage has a stroke dependent on the rails 18 and 19, and is traversed by an operator (not shown) pulling a handle 26 secured to the carriage. The hole saw carriage has a hole saw 28 mounted on a shaft 30, the shaft being powered from a motor 31 through undesignated belts and pulleys. The hole saw rotates about a hole saw axis (not shown) and has a stroke dependent on carriage travel, which stroke passes the saw axially through the log, cutting a saddle cut in the log. The stroke of the hole saw is within a plane normal to the upper rail of the framework.
A forward projecting finger 33 extends from the carriage 22 and projects beyond the hole saw to engage an upper surface 35 of the log 21 before the hole saw starts cutting, the finger restricting upwards movement of the log whilst it is being cut. A contact surface on an underside of the finger is spaced from an outer upper portion of the saw 28 by a distance 37, which distance is approximately equal to radius of the log 21, for a hole saw having an outer diameter approximately equal to diameter of the log being cut. With such a saw the axis of the hole saw is aligned with a lower surface of the log diametrically opposite to the upper surface 35 of the log engaged by the finger. Thus the transverse groove cut in the log extends approximately half way through the log. For a particular saw and finger setting the apparatus 10 cuts one diameter of log only, a change in log diameter requires a change in hole saw diameter and a change in position of the finger relative to the saw. The log 21 is preferably a cylindrical log having been turned on a lathe so as to have zero taper. If such turned logs are used, or if rough logs as cut are used, as previously stated the distance 37 closely approximates the radius of the log. The apparatus 10 has particular application to cut saddles in logs having a radial slot 39 (FIG. 1 only), such a slot providing a means of steadying the log whilst being cut. Further, turned logs that have been axially grooved on an apparatus as described in a patent application of the same inventor entitled "Apparatus for Machining Logs" filed concurrently can also be transversely grooved on the apparatus 10, a small change in the distance 37 being required.
As stated, the log support means 20 is a common roller conveyor, and has a guide blade 40 extending vertically upwards, the guide having a width less than width of the radial slot 39. The radial slot 39 extends inwards from outer surface of the log, the log being carried on an upper surface of the log support with the slot normal to the surface of the log support so that the guide enters the slot. The guide 40 is a sliding fit in the slot and is secured to a shaft 42, which shaft is journalled so that the guide can be swung through an arc 43 so as to engage the slot and be locked in position to prevent rotation or sideways movement of the log as it is cut by the hole saw 28. The log support means is positioned so that the log is within the stroke of the hole saw, so that when the saw is rotating, movement of the hole saw carriage towards the log cuts a transverse groove across the log. The guide 40 is a guide means adjacent the log support to cooperate with the log to restrict the log against horizontal lateral movement and rotation whilst being sawn.
The hole saw has forward projecting teeth mounted on a ring or an end of a cylinder and is adapted to cut a groove and produce only small amounts of saw dust. Other cutters can be used, and hereinafter and in the claims, the term "hole saw" refers to any suitable cutter to produce a groove as above. A hole saw has a tendency to lift a light log off the support means and move it sideways whilst cutting. The finger 33 and guide 40 are provided to restrict such movement, but alternative means can be used, such as clamping the log onto the support means, or using a line bar and crowder roll arrangement, not shown.
The apparatus 10 also has a cut-off saw 47 journalled on an arm 49, the arm extending from a cut-off saw carriage 51 mounted on the upper rail 15. The arm 49 journals the saw 47 at one end for rotation about a cut-off saw axis, and carries a motor 52 at an opposite end remote from the saw, a belt 53 powering the saw. The carriage is positioned between the saw and the motor so that the motor counterbalances essentially the weight of the saw. The arm 49 is journalled to swing about the upper rail so that an outermost portion of the saw 47 swings through an arc 55 in a plane normal to the upper rail, the arc appearing as a broken straight line in FIG. 2. The support means has clearance for the saw 47 as it swings and is positioned so that, for a log of maximum diameter to be handled by the apparatus, an outermost portion of the log is within the arc 55, so as to sever the log in two.
The carriage 51 has rolling means 56 engaging the upper rail 15 and mounting the carriage to be moveable along the upper rail 15 and also to permit rotation of the carriage about the rail, the rolling means to be described with reference to FIGS. 3 and 4. As seen in FIG. 2, the arm 49 extending from the cut-off saw carriage 51 has two spaced longitudinal members 58 and 59. The cut-off saw is adapted to cut a log to length on either side of the saddle cut in the log. Suitable stops (not shown) to limit movement of the cut-off carriage are provided on either side of the hole saw carriage to ensure that, as the saw swings through the arc 55, it does not contact the carriage 22. The stops maintain the cut-off saw at a selected distance from the hole saw, to produce a constant length of log extending from the saddle cut to an outer end face of the log on whichever side of the hole saw the length of log is required. The arc 55 appears as a broken line 61 on the left-hand side of the hole saw as seen in FIG. 2, and as a broken line 62 on the right-hand side.
FIGS. 3 and 4
The rolling means 56 of the carriage 51 has a pair of spaced coplanar grooved rollers 68 and 69 journalled for rotation in brackets 71 and 72. The brackets are secured transversely to the spaced longitudinal members 58 and 59 of the arm 49, the brackets being shown in broken outline in FIG. 3. A third grooved roller 74 is journalled for rotation on a hinged arm 76, the arm 76 being shown in broken outline in FIG. 3. The spaced rollers 68 and 69 are journalled for rotation on one side of the upper rail 15, and the third roller 74 is journalled for rotation on an opposite side of the rail, the rollers being mutually coplanar and clamping the upper rail. The arm 76 is hinged at an end 78 so that swinging of the arm 76 varies spacing between the roller 74 and the spaced rollers 68 and 69. A screw means 80 cooperating with the arm 76 swings the roller 74 and thus permits nice adjustment of clamping pressure between the rollers 68, 69 and 74 and the rail 15 by providing fine adjustment of spacing of the arm 76 from the brackets 71 and 72.
The rolling means 56 permits easy rolling of the cut-off saw carriage 51, along the rail 15 as shown by an arrow 82, FIG. 3, to position the saw 47 relative to a saddle cut. The rolling means also permits rotation of the saw carriage about the rail 15 as shown by an arrow 84, FIG. 4, so as to sever the log in two. The grooved rollers 68, 69, and 74 have a periphery having a cross-section complementary to the upper rail 15. The upper rail 15 has a circular cross-section and the grooved rollers have a periphery having a cross-section that engages the rail, essentially preventing the rollers from moving sideways relative to the rail thus essentially eliminating derailment. The V-section rollers as shown, suitably conventional V-belt pulleys, have been found convenient when used with a rail of suitable diameter. If the rail 15 is fixed, grooves of the rollers journal the rail and form a simple bearing, permitting relatively free rotation of the carriage 51 about the rail 15. To reduce wear of the grooved rollers 68, 69, and 74 when the carriage 51 rotates about the rail 15, ends of the rail can be journalled for rotation in the side frames 13 and 14 of FIG. 1. For a rail 15 of non-circular cross-section, ends of the rail 15 must be journalled in the frames to permit rotation of the rail when the arm 49 swings.
OPERATION
A log 21 is carried on the support means 20 and is positioned so that the hole saw axis is aligned with a selected part of the log, usually adjacent an end, to receive a saddle cut. The shaft 42 is rotated bringing the blade 40 into the slot 39 the slot being normal to the upper surface of the conveyor. The motor 31 is started and the hole saw is moved towards the operator by pulling the handle 26, the finger 33 sliding over the upper surface 35 of the log preventing upward movement of the log whilst the saw 28 cuts the saddle. When the cut is completed the hole saw carriage is returned to a rearward position and, without moving the log 21, the cut-off saw carriage is positioned at a particular side of the saddle cut. The motor 52 is started and the arm 49 is swung so that the saw 47 describes an arc 55 and severs an end off the log thus producing an end face of the log at a particular distance from the saddle cut. For a common wall element, the log 21 is then moved axially so that an opposite end of the log is adjacent the hole saw. The hole saw cuts the saddle cut, and the cut-off saw carriage is then moved along the rail 15 so that the arc described by the saw is now on an opposite side of the saddle cut, thus producing a log cut to length, with the saddle cuts spaced equally from each end.
ALTERNATIVES AND EQUIVALENTS
FIGS. 1 and 2 show an apparatus in which the log support means 20 carries a log in a plane parallel to the upper rail 15, and normal to a plane containing the cut-off saw. This is convenient for most types of log buildings in which adjacent walls at a corner are disposed to each other at a right angle. For other types of corners, where adjacent walls are inclined at other angles, for instance 120 degrees as in a hexagonal building, the log support can be arranged so that the log is fed at an appropriate angle to the hole saw axis and cut-off saw, thus producing oblique cuts in the log.
1. Field of the Invention
The invention relates to an apparatus for cutting a transverse groove to form a saddle cut in a log for use in log cabin construction.
2. Prior Art
Traditionally log cabins were made of logs cut to length, the logs having a saddle cut near each end. At a cabin corner, logs in one wall are staggered between logs in adjacent walls, a saddle cut in one log engaging a respective lower log. The logs used were rough logs, or sometimes debarked, and the saddle cuts were often made with an axe, and such method of construction produced gaps between adjacent logs and ill fitting corners.
It is well known to turn a rough log in a lathe to produce a turned log having a cylindrical outer surface, such turned logs permitting a more accurate cabin construction with reduction of gaps between adjacent logs. Construction with such logs would benefit by providing logs with saddle cuts complementary to an engaging log.
SUMMARY OF THE INVENTION
The invention reduces difficulties of the prior art by providing an apparatus to produce the saddle cuts at ends of logs. This machine can be used with rough logs, but best results are obtained with cylindrically turned logs. A hole saw having a diameter equal approximately to diameter of the logs cuts the saddle cut, and thus essentially uniform complementary contact is obtained between a saddle face of the saddle cut and an adjacent lower log engaged by the saddle cut.
One embodiment of the apparatus has a frame having an upper longitudinal rail and a pair of spaced parallel transverse rails extending transversely across the frame. A cut-off saw carriage mounted with rolling means for movement on the upper rail has an arm journalled to swing about the upper rail. A cut-off saw is mounted on the arm so that swinging of the arm causes the cut-off saw to describe an arc. A hole saw carriage carries the hole saw powered for rotation about a hole saw axis, the carriage mounted on the spaced rails for axial movement of the hole saw, which has a stroke dependent on carriage travel. A log to be grooved is supported and disposed so as to be intersected by the arc described by the cut-off saw as the arm swings, and to be within stroke of the hole saw. Thus movement of the hole saw through the log cuts a transverse groove across the log and swinging of the arm severs the log to cut the log to length.
A detailed description following, related to drawings, describes one embodiment of the invention which however is capable of expression in structure other than that particularly described and illustrated.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified side elevation of an apparatus for grooving logs according to the invention,
FIG. 2 is a simplified front elevation of the apparatus of FIG. 1,
FIG. 3 is a simplified fragmented detail of a portion of a cut-off saw carriage,
FIG. 4 is a simplified fragmented section on 4--4 of FIG. 3.
DETAILED DISCLOSURE
FIGS. 1 and 2
An apparatus 10 according to the invention has a frame 11 having two spaced vertical triangular side frames 13 and 14 joined at upper ends by a longitudinal upper rail 15, and at lower ends by spaced horizontal members 16 and 17. Spaced parallel transverse rails 18 and 19 are secured to the members 16 and 17 and extend transversely from front to back of the frame. A log support means 20, such as a roller conveyor as shown, carries a log 21 which is to be cut to length and provided with saddle cuts.
A hole saw carriage 22 is mounted on wheels severally 23, which wheels run on the rails 18 and 19 so that the hole saw carriage can traverse forwardly in a direction shown by an arrow 24 to produce a saddle cut in the log 21 as will be explained. The carriage has a stroke dependent on the rails 18 and 19, and is traversed by an operator (not shown) pulling a handle 26 secured to the carriage. The hole saw carriage has a hole saw 28 mounted on a shaft 30, the shaft being powered from a motor 31 through undesignated belts and pulleys. The hole saw rotates about a hole saw axis (not shown) and has a stroke dependent on carriage travel, which stroke passes the saw axially through the log, cutting a saddle cut in the log. The stroke of the hole saw is within a plane normal to the upper rail of the framework.
A forward projecting finger 33 extends from the carriage 22 and projects beyond the hole saw to engage an upper surface 35 of the log 21 before the hole saw starts cutting, the finger restricting upwards movement of the log whilst it is being cut. A contact surface on an underside of the finger is spaced from an outer upper portion of the saw 28 by a distance 37, which distance is approximately equal to radius of the log 21, for a hole saw having an outer diameter approximately equal to diameter of the log being cut. With such a saw the axis of the hole saw is aligned with a lower surface of the log diametrically opposite to the upper surface 35 of the log engaged by the finger. Thus the transverse groove cut in the log extends approximately half way through the log. For a particular saw and finger setting the apparatus 10 cuts one diameter of log only, a change in log diameter requires a change in hole saw diameter and a change in position of the finger relative to the saw. The log 21 is preferably a cylindrical log having been turned on a lathe so as to have zero taper. If such turned logs are used, or if rough logs as cut are used, as previously stated the distance 37 closely approximates the radius of the log. The apparatus 10 has particular application to cut saddles in logs having a radial slot 39 (FIG. 1 only), such a slot providing a means of steadying the log whilst being cut. Further, turned logs that have been axially grooved on an apparatus as described in a patent application of the same inventor entitled "Apparatus for Machining Logs" filed concurrently can also be transversely grooved on the apparatus 10, a small change in the distance 37 being required.
As stated, the log support means 20 is a common roller conveyor, and has a guide blade 40 extending vertically upwards, the guide having a width less than width of the radial slot 39. The radial slot 39 extends inwards from outer surface of the log, the log being carried on an upper surface of the log support with the slot normal to the surface of the log support so that the guide enters the slot. The guide 40 is a sliding fit in the slot and is secured to a shaft 42, which shaft is journalled so that the guide can be swung through an arc 43 so as to engage the slot and be locked in position to prevent rotation or sideways movement of the log as it is cut by the hole saw 28. The log support means is positioned so that the log is within the stroke of the hole saw, so that when the saw is rotating, movement of the hole saw carriage towards the log cuts a transverse groove across the log. The guide 40 is a guide means adjacent the log support to cooperate with the log to restrict the log against horizontal lateral movement and rotation whilst being sawn.
The hole saw has forward projecting teeth mounted on a ring or an end of a cylinder and is adapted to cut a groove and produce only small amounts of saw dust. Other cutters can be used, and hereinafter and in the claims, the term "hole saw" refers to any suitable cutter to produce a groove as above. A hole saw has a tendency to lift a light log off the support means and move it sideways whilst cutting. The finger 33 and guide 40 are provided to restrict such movement, but alternative means can be used, such as clamping the log onto the support means, or using a line bar and crowder roll arrangement, not shown.
The apparatus 10 also has a cut-off saw 47 journalled on an arm 49, the arm extending from a cut-off saw carriage 51 mounted on the upper rail 15. The arm 49 journals the saw 47 at one end for rotation about a cut-off saw axis, and carries a motor 52 at an opposite end remote from the saw, a belt 53 powering the saw. The carriage is positioned between the saw and the motor so that the motor counterbalances essentially the weight of the saw. The arm 49 is journalled to swing about the upper rail so that an outermost portion of the saw 47 swings through an arc 55 in a plane normal to the upper rail, the arc appearing as a broken straight line in FIG. 2. The support means has clearance for the saw 47 as it swings and is positioned so that, for a log of maximum diameter to be handled by the apparatus, an outermost portion of the log is within the arc 55, so as to sever the log in two.
The carriage 51 has rolling means 56 engaging the upper rail 15 and mounting the carriage to be moveable along the upper rail 15 and also to permit rotation of the carriage about the rail, the rolling means to be described with reference to FIGS. 3 and 4. As seen in FIG. 2, the arm 49 extending from the cut-off saw carriage 51 has two spaced longitudinal members 58 and 59. The cut-off saw is adapted to cut a log to length on either side of the saddle cut in the log. Suitable stops (not shown) to limit movement of the cut-off carriage are provided on either side of the hole saw carriage to ensure that, as the saw swings through the arc 55, it does not contact the carriage 22. The stops maintain the cut-off saw at a selected distance from the hole saw, to produce a constant length of log extending from the saddle cut to an outer end face of the log on whichever side of the hole saw the length of log is required. The arc 55 appears as a broken line 61 on the left-hand side of the hole saw as seen in FIG. 2, and as a broken line 62 on the right-hand side.
FIGS. 3 and 4
The rolling means 56 of the carriage 51 has a pair of spaced coplanar grooved rollers 68 and 69 journalled for rotation in brackets 71 and 72. The brackets are secured transversely to the spaced longitudinal members 58 and 59 of the arm 49, the brackets being shown in broken outline in FIG. 3. A third grooved roller 74 is journalled for rotation on a hinged arm 76, the arm 76 being shown in broken outline in FIG. 3. The spaced rollers 68 and 69 are journalled for rotation on one side of the upper rail 15, and the third roller 74 is journalled for rotation on an opposite side of the rail, the rollers being mutually coplanar and clamping the upper rail. The arm 76 is hinged at an end 78 so that swinging of the arm 76 varies spacing between the roller 74 and the spaced rollers 68 and 69. A screw means 80 cooperating with the arm 76 swings the roller 74 and thus permits nice adjustment of clamping pressure between the rollers 68, 69 and 74 and the rail 15 by providing fine adjustment of spacing of the arm 76 from the brackets 71 and 72.
The rolling means 56 permits easy rolling of the cut-off saw carriage 51, along the rail 15 as shown by an arrow 82, FIG. 3, to position the saw 47 relative to a saddle cut. The rolling means also permits rotation of the saw carriage about the rail 15 as shown by an arrow 84, FIG. 4, so as to sever the log in two. The grooved rollers 68, 69, and 74 have a periphery having a cross-section complementary to the upper rail 15. The upper rail 15 has a circular cross-section and the grooved rollers have a periphery having a cross-section that engages the rail, essentially preventing the rollers from moving sideways relative to the rail thus essentially eliminating derailment. The V-section rollers as shown, suitably conventional V-belt pulleys, have been found convenient when used with a rail of suitable diameter. If the rail 15 is fixed, grooves of the rollers journal the rail and form a simple bearing, permitting relatively free rotation of the carriage 51 about the rail 15. To reduce wear of the grooved rollers 68, 69, and 74 when the carriage 51 rotates about the rail 15, ends of the rail can be journalled for rotation in the side frames 13 and 14 of FIG. 1. For a rail 15 of non-circular cross-section, ends of the rail 15 must be journalled in the frames to permit rotation of the rail when the arm 49 swings.
OPERATION
A log 21 is carried on the support means 20 and is positioned so that the hole saw axis is aligned with a selected part of the log, usually adjacent an end, to receive a saddle cut. The shaft 42 is rotated bringing the blade 40 into the slot 39 the slot being normal to the upper surface of the conveyor. The motor 31 is started and the hole saw is moved towards the operator by pulling the handle 26, the finger 33 sliding over the upper surface 35 of the log preventing upward movement of the log whilst the saw 28 cuts the saddle. When the cut is completed the hole saw carriage is returned to a rearward position and, without moving the log 21, the cut-off saw carriage is positioned at a particular side of the saddle cut. The motor 52 is started and the arm 49 is swung so that the saw 47 describes an arc 55 and severs an end off the log thus producing an end face of the log at a particular distance from the saddle cut. For a common wall element, the log 21 is then moved axially so that an opposite end of the log is adjacent the hole saw. The hole saw cuts the saddle cut, and the cut-off saw carriage is then moved along the rail 15 so that the arc described by the saw is now on an opposite side of the saddle cut, thus producing a log cut to length, with the saddle cuts spaced equally from each end.
ALTERNATIVES AND EQUIVALENTS
FIGS. 1 and 2 show an apparatus in which the log support means 20 carries a log in a plane parallel to the upper rail 15, and normal to a plane containing the cut-off saw. This is convenient for most types of log buildings in which adjacent walls at a corner are disposed to each other at a right angle. For other types of corners, where adjacent walls are inclined at other angles, for instance 120 degrees as in a hexagonal building, the log support can be arranged so that the log is fed at an appropriate angle to the hole saw axis and cut-off saw, thus producing oblique cuts in the log.