Note: Descriptions are shown in the official language in which they were submitted.
2197fi~3
TABLE SAW FENCE
FIELD OF THE INVENTION
The present invention relates to table saw
~ences and, more specifically, to table saw fences
adapted to maintain one surface of a workpiece
parallel to a cutting line defined by the table
saw blade.
BACKGROUND OF THE INVENTION
Table saws are often provided with fences
against which the workpiece being cut is held
while certain cuts are being made. Such fences
normally have a planar abutment surface against
which the wood is held as it is cut and are
adapted to move towards and away from the cutting
blade. They are often made to be removable so
that the table saw can be used without the fence.
Table saw fences comprise two basic
subsystems to perform their intended function.
The first is a suspension system for mounting the
fence on to the table saw in a manner that allows
the fence to be moved away from and towards the
saw blade. The second is a locking system that
allows the table saw fence to be locked into place
at a desired location so that the fence will not
shift while the cut is being made and a number of
successive identical cuts may be made.
The most typical table saw fence employs a
suspension system comprising parallel tubes
mounted on either side of the fence perpendicular
'- 219763~
--2--
to the cutting line of the saw blade. The fence
has slide members arranged to engage the tubes
such that the fence is supported at either end by
the tubes in a manner that allows the fence to
slide towards and away from the saw blade. The
clamping system comprises a lever mounted on one
end of the fence, where downward rotation of the
lever causes the tube adjacent to that lever to be
gripped to fix one end of the fence at a desired
location. U.S. Pat. No. 4,206,910 to Biesemeyer
describes a table saw fence of this basic type.
This most typical type of table saw fence is
simple to manufacture and operate because it has
very few moving parts, is easily removable, and
does not require significant adjustment upon set
up. But because it locks only one end of the
fence relative to the table, this type of fence
does not guarantee that its abutment surface will
stay parallel to the table saw blade while a cut
is being made or between successive cuts.
Additionally, the clamping action tends to shift
the abutment surface slightly, and it is difficult
to predict exactly how much shift this will cause.
Accordingly, while simple in design, construction,
and operation, this type of table saw fence using
tubes and locking at one end does not always
result in precise, reliable cuts.
Another type of table saw fence is shown in
U.S. Pat. No. 4,521,006 to Waters. The Waters
patent describes a table saw fence having a cable
based suspension system and a locking system that
locks both ends of the table saw fence relative to
the table saw. More specifically, both ends of
21976~
the table saw fit into blocks connected to an
endless cable such that movement of one end is
translate to the other end through the cable and
blocks. The locking system comprises a lever
member which, when downwardly rotated, acts
through a linkage on the blocks connected to the
cable to force these blocks against the rail
members on which the fence member is mounted.
The Waters system relies entirely on the
cables to maintain the abutment surface of the
fence parallel to the cutting line defined by the
saw blade. If these cables are stretched or are
out of alignment when assembled, the abutment
surface will not be parallel to the cutting line.
Not only is this system difficult to keep in
alignment, but it is relatively expensive and
complicated to implement.
Another type of fence system is available on
the market from Excalibur Machine & Tool Co. The
Excalibur fence employs parallel rail members
mounted on either side of the saw blade orthogonal
to the cutting line. Three horizontal roller
members are employed as a suspension system. In
particular, two roller members are mounted on one
end of the table saw fence and one other member is
mounted on the other end of the table saw fence.
These members have annular notches that receive
edges of the rail members to support the fence
above the table. The locking system of the
Excalibur fence comprises a lever mounted on one
end of the fence and a connecting rod extending
through the fence, which is in turn connected to
the roller at the other end. Downward rotation of
219763~
the lever causes the roller member at the other
end to move towards the table, thereby pinching
the table between the two ends of the fence. The
entire pinching load is born by the rollers.
While some advantage is obtained by the
three-point roller arrangement used as a
suspension system, the smoothness of operation and
adjustability of this fence are limited by the
fact that the rollers are used as part of the
locking system. This locking system also tends to
shift the abutment surface as the lock is engaged,
making precise alignment of cuts difficult.
Accordingly, the need exists for a table saw
fence that maintains a planar abutment surface
thereon in a desired relationship to the saw blade
while unlocked, may be easily locked in a desired
location, is simple to use but adjustable, and
moves along the fence in a smooth manner.
SUMMARY OF THE INVENTION
The present invention is a table saw fence
system adapted to be mounted on a table saw. The
fence system includes a fence member having an
abutment surface formed thereon and is designed to
maintain this abutment surface orthogonal to a
cutting surface defined by the table saw and
parallel to a cutting line defined by the blade of
the saw.
The fence system constructed in accordance
with the present invention is an assembly
comprising a fence member, a suspension or support
system, and a locking system. The support system
2197633
-
supports the fence member above a work surface of
the table saw. The locking system locks the fence
member in a desired location on the saw and is
entirely separate from the support system,
allowing the support system to be designed for
smooth operation and adjustability.
In one embodiment, the locking system
comprises two sets of jaw members located on
opposite ends of the fence assembly. Each of the
jaw members receives an outwardly extending flange
portion of a rail member securely attached to the
saw. Each of the jaw members independently
pinches its respective rail flange such that the
locations of both ends of the fence assembly are
independently locked relative to the table saw.
The locking system thus does not require the
support assembly to bear the loads required to
lock the fence assembly in a desired location on
the table saw. The support system thus may use
rather delicate bearings such as ball bearings and
may be made adjustable to allow the abutment
surface on the fence to be kept parallel to the
cutting line and orthogonal to the work surface.
The support system itself comprises three
rollers and a bearing assembly for each of the
rollers. One of the bearing assemblies allows its
associated roller to be moved up and down relative
to the carriage on which the roller is mounted.
Another of the bearing assemblies allows the
roller associated therewith to be moved laterally
relative to the carriage. A third roller is
mounted on a carriage on the opposite end of the
fence assembly and is spring-biased to keep a
21g7633
predetermined load on the various rollers. The
third bearing assembly is designed so that the
load applied thereby can be varied to ensure that
the rollers are always in contact with their
associated rail flanges, but the load applied
thereby is not too large that the bearings
employed are damaged or prematurely worn.
The result is a fence assembly that is highly
adjustable, operates very smoothly, and which may
be securely locked in a desired location relative
to the saw blade. These and other advantages of
the present invention will become apparent from
the following detailed discussion of the
invention.
- 219763~
OBJECTS OF THE INVENTION
From the foregoing, it should be clear that
one object of the present invention is to provide
an improved table saw fence for use on table saws.
Another more specific object of the present
invention is to provide a table saw fence system
having one or more of the following
characteristics:
allows adjustment of an orientation of
an abutment surface on a fence member to be
adjusted relative to a cutting line defined by the
table saw;
allows both ends of the table saw to be
moved at the same time without separately
interconnecting these ends by cables or the like;
allows the fence member to be locked in
a desired location without exerting a lateral
force on the table saw;
is easily adapted for use as a retrofit
kit as well as to be installed on the table saw at
the factory; and
may be easily and inexpensively
constructed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a table
saw incorporating a table saw fence constructed in
accordance with, and embodying, the principles of
the present invention;
FIG. 2 is a top plan view of the table saw
shown in FIG. 1;
-- 21976~3
--8--
FIG. 3 is a top plan view showing details of
construction of the fence used by the table saw
shown in FIGS. 1 and 2;
FIGS. 4 and 5 are side cutaway view taken
along lines 4-4 and 5-5, respectively, showing
details of the roller mounts employed by the fence
shown in FIG. 3;
FIG. 6 is a bottom cutaway view taken along
lines 6-6 in FIG. 5 showing details of
construction and operation of the roller mount
bearing assembly depicted in FIG. 5;
FIG. 7 is a cutaway view taken along
lines 7-7 in FIG. 3 showing details of
construction of a spring-loaded bearing assembly
employed by the fence shown in FIG. 3;
FIGS. 8A and 8B show details of construction
and operation of a locking system employed by the
table saw fence taken along lines 8-8 in FIG. 2,
the locking system being shown in its open
position;
FIGS. 9A and 9B show details of construction
and operation of a locking system employed by the
table saw fence taken along lines 8-8 in FIG. 2,
the locking system being shown in its closed
position;
FIG. 10 is a perspective view of a linkage
assembly employed by the locking system depicted
in FIGS. 8A, 8B, 9A, and 9B; and
FIG. 11 is a section view taken along
lines 11-11 in FIG. 2; and
FIGS. 12-13 are side cut-away views showing a
second embodiment of a locking system embodying
the principles of the present invention.
21976~
DETAILED DESCRIPTION
Referring to FIG. 1 of the drawing, depicted
at 20 therein is a table saw on which is mounted a
table saw fence system 22 that is constructed in
accordance with, and embodies, the principles of
the present invention.
The table saw 20 is conventional and will be
described herein only to the extent necessary for
a complete understanding of the construction and
operation of the fence system 22.
Table saw 20 comprises a saw blade 24 and a
work surface 26. The saw blade 24 lies partially
above and partially below the work surface 26.
During a cutting operation, the saw blade 24
is rotated and a workpiece is placed on the work
surface 26 and displaced until it contacts the saw
blade 24. As the workpiece is moved past the saw
blade 24, the blade cuts the workpiece.
The work surface 26 defines a work plane 28
that is substantially parallel to the surface of
the paper in FIGS. 2 and 3. A cutting plane 30 is
defined as the plane in which the saw blade 24
resides. Often, but not always, the cutting
plane 30 is orthogonal to the support plane 28.
The intersection between the support plane 28 and
cutting plane 30 is defined as a cutting line 32.
The fence system 22 defines an abutment
surface 34 that resides in a bracing plane 36. In
a perfectly adjusted fence, the bracing plane 36
will be orthogonal to the support plane 28 and
parallel to the cutting line 32. When referring
to a fence as being ~skewed" relative to the saw
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- 10 -
blade, what is meant is that the bracing plane is
not parallel to the cutting line.
Referring now to the fence system 22, FIG. 2
shows that the fence system 22 basically comprises
a first rail 38, a second rail 40, and a fence
assembly 42.
The rails 38 and 40 are mounted on either
side of the table saw 20. Ideally, the rail
members 38 and 40 are parallel to the support
surface 28 and orthogonal to the cutting line 32.
The fence assembly 42 basically comprises a
support assembly 44 (FIGS. 3, 4, 5, 6, and 7) for
allowing the assembly 42 to be mounted onto the
rails 38 and 40, a fence member 46 (FIGS. 1, 2,
and 11) on which the abutment surface 34 is
formed, and a locking system 48 (FIGS. 8A, 8B, 9A,
9B, and 10) for fixing the rail member 46 in a
desired location relative to the blade 24.
Referring initially to the support
assembly 44, this assembly has a first carriage 50
and second carriage 52 mounted on first and second
ends 54 and 56, respectively, of the fence
assembly 42. As perhaps best shown in FIG. 3,
mounted within the first carriage 50 are first and
second rollers 58 and 60, and mounted within the
second carriage 52 is a third roller 62. The
rollers 58, 60, and 62 are mounted on their
respective carriages 50 and 52 in a generally
triangular configuration.
The rollers 58 and 60 are identical and only
the roller 58 will be described herein in detail
with the understanding that this description
applies to the roller 60 as well. Roller 62 is
-- 2197633
similar to the roller 58 and will be described
separately below.
As shown in FIG. 4, the roller 58 is
generally disk-shaped in overall configuration and
has an upper surface 64, lower surface 66, and an
outer surface 68. The upper and lower surfaces 64
and 66 are substantially planar, while the outer
surface 68 is substantially cylindrical. An
annular groove 70 is formed in the outer
surface 68. This groove 70 is defined by a lower
groove surface 72, upper groove surface 74, and
inner groove surface 76.
The annular groove 70 on the first roller 58
is sized and dimensioned to receive, with generous
tolerances, an outwardly extending first flange 78
that forms a part of the first rail member 38.
The flange 78 has an upper surface 80, lower
surface 82, and edge surface 84.
The annular groove 70 receives the edge
surface 84 and portions of the upper and lower
surfaces 80 and 82. The second roller 60
similarly engages the first flange 78, while the
third roller 62 engages a similar outwardly
extending second flange 86 of the second rail
member 40.
The weight of the fence assembly 42 and any
loads on fence assembly 42 are thus borne by the
engagement of the rollers 58, 60, and 62 with the
rail flanges 78 and 86.
Each of the rollers 58, 60, and 62 has a
roller bearing assembly associated therewith that
mounts the roller onto its respective carriage.
FIG. 4 shows a first bearing assembly 88 that
-- 21976~3
mounts the first roller 58 on to the first
carriage 50. The bearing assembly 88 allows the
distance between the roller 58 and the carriage 50
to be changed.
A second bearing assembly 90 ( FIGS. 5 and 6)
connects the second roller 60 on to the
carriage 50 such that the roller 60 may be moved
laterally relative to the carriage 50.
A third bearing assembly 92 (FIG. 7) mounts
the third roller 62 on to the second carriage 52.
The third bearing assembly 92 applies constant
pressure on the roller 62 to force this roller
against its associated rail flange 86.
Referring now in detail to the bearing
15 assembly 88, FIG. 4 shows that this assembly 88
comprises a bolt member 94, a threaded sleeve
member 96, a set screw 98, a plug 100, and a ball
bearing 102. The bolt 94 has a threaded
portion 104, while the sleeve 96 has an externally
threaded surface 106 and an internally threaded
surface 108 adapted to receive the threaded
portion 104 of the bolt 94.
The carriage 50, or a member securely
fastened thereto, is tapped to form a cavity 110
defined by a threaded surface 112 adapted to
receive the externally threaded surface 106 of the
sleeve 96. The carriage 50 or member affixed
thereto also includes a set screw cavity 114
defined by a surface 116 having a threaded
30 portion 118, an outer surface 120 of the set
screw 98 is adapted to mate with the threaded
portion 118. The set screw cavity 114 iS in
communication with the bearing cavity 110.
2l976~3
In use, the bolt 94 is threaded into the
sleeve 96 and secured with Loctite or other
adhesive such that subsequent movement of the
bolt 94 relative to the sleeve 96 is prevented.
In the bearing assembly 88, a longitudinal axis A
of the sleeve 96 is aligned with a longitudinal
axis B of the bolt 94.
The ball bearing 102 is securely attached
between the bolt 94 and the sleeve 96. The
roller 58 is borne by the ball bearing 102 such
that the roller 58 smoothly rotates about a
central axis B of the bolt 94.
Additionally, by rotating the set screw 98
such that it is displaced towards the bearing
cavity 110, a force is applied through the
plug 100 that prevents movement of the sleeve 96
relative to the carriage 50. On the other hand,
rotating the set screw 98 such that it moves away
from the bearing cavity 110 disengages the
plug 100 from the sleeve 96 such that the
sleeve 96 may rotate relative to the carriage 50.
The plug 100 is made out of a relatively soft
material such as plastic to prevent damage to the
sleeve 96.
Because the bolt 94 is rigidly connected to
the sleeve 96, rotation of the bolt 94 about its
central axis A causes rotation of the sleeve 96
that displaces the roller 58, ball bearing 102,
bolt 94, and sleeve 96 along the central axis A.
The first bearing assembly 88 thus allows the
roller 58 to be moved towards and away from the
carriage 50 along the central axis A.
~1976~3
-14-
The second bearing assembly 90 is similar to
the first bearing assembly 88 in all respects
except one: the longitudinal axis A of the bolt
is offset from the longitudinal axis B of the
sleeve. Accordingly, as shown in FIG. 6, rotation
of the bolt and sleeve causes a lateral
displacement of the roller 60 in the direction as
shown by arrows C in FIGS. 5 and 6.
The bearing assemblies 88 and 90 thus allow
the orientation of the reference plane 36 relative
to the cutting line 32 to be altered such that the
plane 36 is parallel to the line 32. More
specifically, the first bearing assembly 88 allows
the reference plane 36 to be rotated in an arc as
shown by line D in FIG. 1, while the second
bearing assembly 90 allows the reference plane 36
to be pivoted in the direction shown by arrow E in
FIG. 2. Using these adjustments, the reference
plane 36 may be made substantially parallel to the
cutting line 30 and orthogonal to the support
plane 28.
The third bearing assembly 92 is provided to
apply a predetermined biasing force to the third
roller member 62 such that all of the rollers 58,
60, and 62 are held against their respective rail
flanges 78 and 86.
Referring to FIGS. 3 and 7, it can be seen
that the third roller bearing assembly 92
comprises a pivot member 122 attached to the
second carriage 52 by a bolt 124. A spring 126
provides the biasing force, and an adjustment
assembly 128 to allow the amount of the biasing
force to be adjusted.
2197fi3~
More specifically, one end of the spring 26
is attached to a pin 130 connected to the
carriage 52, and a second end of the spring 126 is
attached to a threaded adjustment rod 132. An
adjusting wheel is rotatably mounted on to the
rod 132 such that rotation of the wheel 134
relative to the rod 132 displaces the wheel 134
along a longitudinal axis of the rod 132. The
wheel 134 is securely connected to the pivot
member 122 such that rotation of the wheel
member 134 causes the pivot member 122 to rotate
about the bolt 124. Rotation of the wheel 134
thus allows the biasing force applied by the third
roller 62 on to the rail flange 86 to be increased
and/or decreased.
The third roller 62 is mounted on a ball
bearing 136 that is in turn mounted on a shaft 138
formed on a post 140. A retaining 142 is employed
to attach the ball bearing 136 on to the post 140.
The third roller 62 is similar to the first
and second rollers 58 and 60 in that it has an
annular groove 144 formed therein for receiving
the second rail flange 86, but is slightly smaller
in diameter and somewhat thinner.
As described above, the support assembly 42
mounts the fence assembly 54 on to the rails 38
and 40 at three bearing locations and in a manner
that allows the orientation of the reference
plane 36 to be adjusted.
Additionally, each of the rollers 58, 60,
and 62 is mounted on its respective carriage 50
or 52 through a ball bearing assembly. This
results in very smooth movement as the fence
2197633
.
-16-
assembly is moved towards and away from the saw
blade 24.
The biasing force applied by the third
bearing assembly 92 allows an amount of horizontal
load borne by the bearing assemblies 88, 90,
and 92 to be small enough to prevent premature
wear by the ball bearing assemblies employed but
large enough so that the flanges 78 and 86 are
securely received within the grooves 70 and 144.
Referring now to FIGS. 8, 9 and 10, the
locking system 48 will be described in further
detail. The locking system as shown in its open
position in FIGS. 8A and 8B and in its closed
position in FIGS. 9A and 9B. The locking
system 48 grips the outwardly extending flanges 78
and 86 of the rail members 38 and 40 to lock the
fence in a desired location. The locking
system 48 thus does not rely on a large horizontal
locking force that is borne by the support
system 42 to fix the fence assembly 22 in its
desired location. The locking system 48 thus
allows the use of the ball bearings and the
tensioning bearing assembly 92 as described above.
A first section 150 of the locking system 48
2 5 is shown in FIGS. 8A and 9A, while a second
section 152 iS shown in FIGS. 8B and 9B. AS will
be described in further detail below, these first
and second sections 150 and 152 are interconnected
by a tie rod 154. A first section 150 iS mounted
in the first carriage 50, while the second
section 152 iS mounted in the second carriage 52.
The tie rod 154 extends through the center of the
219~633
-17-
fence member 46 from the first end 54 to the
second end 56 of the fence assembly 22.
Referring initially to the first section 150,
it can be seen that this section 150 comprises
first (upper) and second (lower) jaw members 156
and 158, a linkage assembly 160, and an actuator
shaft 162. By comparing FIGS. 8A and 9A, it can
be seen that movement of the actuator shaft 162
acts on the jaw members 156 and 158 through the
linkage assembly 160 such that the jaw members 156
and 158 grip the first rail flange 78.
More specifically, the linkage assembly 160
comprises: (a) a rocker plate 164 operatively
connected to the carriage 50 by a pivot pin 166;
(b) a first yoke assembly 168 attached to the
pivot plate 164 by a pin 170 and the first jaw
member 156 by a pin 172; and (c) a second yoke
assembly 174 attached to the pivot plate 164 by a
pin 176 and the second jaw member 158 by a
pin 178.
Additionally, the first and second jaw
members 156 and 158 are pivotally connected to
rotate relative to each other around a gripping
axis F extending through a pin 180. More
specifically, a pair of gripping plates 182
(FIG. 10) is securely attached to either side of
the first jaw member 156 and overlaps the second
jaw member 158 such that the pin 180 rotatably
connects the gripping plates 182 to the second jaw
member 158.
Comparing FIGS. 8A and 8B, it can be seen
that the actuator shaft 162 moves laterally
between first and second positions. The rocker
21976~
-18-
plate 164 rotates between first and second
orientations corresponding to the first and second
position of the actuator shaft 162 because it is
connected to the actuator shaft 162 by a pin 181.
In the first orientation, the pins 170
and 176 extending through the rocker plate 164 are
at approximately the same horizontal level. In
the second orientation shown in FIG. 9A, the
pin 170 is slightly higher than the pin 176.
When the rocker plate 164 is in the first
orientation, a gap 184 exists between first and
second engaging surfaces 186 and 188 formed on the
first and second jaw members 156 and 158,
respectively. The rail flange 78 extends into
this gap 184 between the surfaces 186 and 188.
Under normal conditions, gravity causes the
engaging surface 186 to be in contact with the
upper surface 80 of the flange 78. The lower
engaging surface 188 does not come into contact
with the lower surface 82 of the flange 78 when
the jaw members are in the open position as shown
in FIG. 8A but does engage the lower surface 82
when the jaw members are in the closed position
shown in FIG. 9A.
More specifically, gravity causes the upper
engaging surface 186 to stay in contact with the
flange upper surface 80 as long as the flange 78
is within the gap 184. As the rocker plate pivots
about the pin 166 from the first to the second
orientation, the yoke assembly 168 causes the
pin 172 to move upward. As the pin 172 is
connected to the upper jaw member 156, this jaw
member 156 pivots upwardly about the point where
.- 2197623
- 1 9 -
the upper engaging surface 186 contacts the flange
upper surface 180. As the pivot plate 182 is
securely connected to the upper jaw member 156,
the pivot pin 180 raises slightly along with the
upper jaw member 156.
At the same time, rotation of the rocker
plate 164 from the first into the second
orientation causes the pin 176 to rotate
downwardly around the pin 166. This downward
movement of the pin 176 displaces the yoke 174
such that the pin 178 is also moved downwardly.
The combination of the upward movement of the
pin 180 and downward movement of the pin 178
causes the surface 188 to be moved up while at the
same time being rotated about the gripping axis F.
With appropriate adjustment of the length of
the yoke assemblies 168 and 174, movement of the
rocker plate from the first into the second
orientation results in the lower gripping
surface 188 engaging the lower surface 82 of the
flange 78 as shown in FIG. 9A. At this point, the
flange 78 is securely gripped between the engaging
surfaces 186 and 188 on the jaw members 156
and 158. Movement between these jaw members 156
and 158 and the flange 78 is prevented when the
jaw members are in this closed position.
To prevent movement between the jaw
members 156 and 158 and the carriage 50, a jaw
housing 190 is integrally formed on the underside
of the fence carriage 50. The jaw housing 190
defines an interior chamber 196 in which the upper
jaw 156 and portions of the yoke assemblies 168
and 174 reside. A lower portion 198 of the
- 219763~
-20-
chamber 196 is in the form of a slot sized and
dimensioned to snugly receive the upper jaw 156 in
a manner that prevents movement of the carriage 50
towards and away from the saw blade 24 relative to
the upper jaw member 156.
Accordingly, when the jaw members 156 and 158
are clamped on to the flange 78, movement of the
carriage 50 along the rail 38 is substantially
eliminated.
As described above, the actuator shaft 162 is
displaced in the directions shown by arrow G in
FIGS. 8A and 9A to displace the rocker plate 164
between the first and second configurations. To
facilitate movement of the actuator shaft 162 as
required, a handle assembly 200 is provided. The
handle assembly 200 comprises a handle member 202,
a handle cover 204, a handle link 206, a first
pin 208, and second pin 210, and a third pin 212.
The handle member 202 is configured for easy
gripping and in the exemplary handle assembly 200
is rectangular in cross section. The handle
cover 204 provides an enhanced grip to the handle
member 202. The handle member 202 is rotatably
connected to the actuator shaft 162 by the first
pin 208. The second pin 210 operatively fixes one
end of the handle link 206 relative to the
carriage 50, while the third pin 212 connects the
other end of the handle link 206 to the handle
member 202.
The handle link 206 is connected between an
end cap 213 and the handle member 202 and the
actuator shaft 162 is connected to the handle
member 202 such that downward movement of the
219~633
-21-
handle member 202 displaces the actuator
member 162 slightly out through the end cap 213.
This movement of the actuator shaft 162 causes the
rocker plate 164 to move from the first into the
second orientation.
By arranging the pins 208, 210, and 212 such
that the pin 212 is substantially lower than the
pin 210 when the handle member 202 is up and
substantially at the same horizontal level as the
pins 208 and 210 when the handle member 202 is
down, an over-center locking action is obtained
that holds the handle member 202 in the down
position. This locking action can be overcome
simply by raising the handle member 202 into the
position shown in FIG. 8A. Raising the handle
member 202 also displaces the actuator shaft 162
in through the end cap 213 and moves the rocker
plate 164 from the second into the first
orientation.
As described above, the locking system 48
comprises first and second sections 150 and 152.
The second section 152 is shown in FIGS. 8B
and 9B. As shown, the second section 152
comprises a first (upper) jaw member 214, a second
(lower) jaw member 216, and a linkage assembly 218
connected between the tie rod 154 and the jaw
members 214 and 216. The linkage assembly 218
comprises a rocker plate 220, operatively
connected by a pin 222 to the carriage 52, a first
yoke assembly 224 connected between the rocker
plate 220 and the upper jaw member 214 by pins 226
and 228 and a second yoke assembly 230 connected
21g7633
between the rocker plate 220 and lower jaw
member 216 by pins 232 and 234.
Also shown in FIG. 8B is a return spring 236
connected between the rocker plate 220 and an end
cap 237.
The linkage assembly 218 operates in the same
basic manner as the assembly 160 described above
and will be described herein only to the extent
that the linkage assemblies differ.
The rocker plate 220 of the linkage
assembly 218 is not connected directly to the
actuator shaft 162 but is instead indirectly
connected thereto via the rocker plate 164 and the
tie rod 154.
More particularly, the tie rod 154 is
pivotally attached to the rocker plate 164 by a
pin 164a and to the rocker plate 220 by a
pin 220a. Movement of the actuator shaft 162 in
the direction shown by arrow G in FIG. 8A is thus
translated to the rocker plate 220 through the
rocker plate 164 and tie rod 154. Movement of the
actuator shaft 162 thus causes the rocker
plate 220 to move between first and second
orientations as shown on FIGS. 8B and 9B,
respectively.
The return spring 236 exerts a return biasing
force on the rocker plate 220 that biases this
plate 220 into the first orientation. This force
is transmitted through the rocker plate 220, tie
rod 154, rocker plate 164, and actuator shaft 162
to the handle member 202. The spring 236 thus
biases the handle member 202 into the upper
position shown in FIG. 8A.
219763~
.,
The linkage assembly 218 differs slightly
from the linkage assembly 160 in that the yoke
assemblies 224 and 230 face different directions
relative to the yoke assemblies 168 and 174. This
is because the rocker plates 164 and 220 both
rotate in the same direction, but the jaw
members 214 and 216 are extending in the opposite
direction towards the rail flange 86 relative to
the jaw members 156 and 158. The length of these
yoke assemblies 224 and 230 are shorter than the
lengths of the assemblies 168 and 174 as the rail
member 40 is located at a higher elevation than
the rail member 38.
Rotation of the rocker plate 220 about the
pin 222 displaces the yoke jaw members 214 and 216
through the yoke members 224 and 230 to reduce a
gap 238 between an upper engaging surface 240 on
the jaw member 214 and a lower engaging
surface 242 on the jaw member 216, thereby
gripping the rail flange 86 between the
surfaces 240 and 242.
Again, a jaw housing 244 is integrally formed
with the carriage 52 to prevent relative movement
between the jaw member 214 and the carriage 52.
Thus, when these jaw members 214 and 216 are
locked onto the flange 86, the carriage 52 does
not move towards or away from the saw blade 24.
Moving the handle member 202 from the upper
position shown in FIG. 8A to the lower position
shown in FIG. 9A thus causes the jaw members 156,
158, 214, and 216 to grip the rail flanges 78
and 86 and thereby fix the carriages 50 and 52
relative to the saw blade 24. As the carriages 50
2197~3
-24-
and 52 are rigidly connected to the fence
member 46, the fence member 46 and the bracing
surface 34 formed thereon are also locked relative
to the saw blade 24.
It also important to note what the locking
system 48 does not do when fixing the fence
member 46 at the desired location. The locking
system 48 does not exert any lateral forces on the
rollers 58, 60, or 62. The bearing assemblies 88,
90, and 92 that support these rollers 58, 60,
and 62 may thus be designed to support the fence
assembly 22 on to the saw 20 in a manner that
allows this fence assembly 22 to be smoothly moved
towards and away from the saw blade 24 and
adjusted so that the abutment plane 36 is both
orthogonal to the surface plane 28 and parallel to
the cutting line 32.
The fence assembly 22 may be installed on the
saw 20 at the factory or may be retrofitted on to
a previously manufactured saw by the end user.
Especially in the case of a retrofit, the
significant adjustability of the various
components of the fence assembly 22 is important.
For example, the fact that the rail members 78
and 86 are received within gaps defined by their
respective jaw members means that the distance
between these rail members 38 and 40 is not
critical. Further, if the rail members 38 and 40
are not parallel to each other, this can be
accommodated to some extent by adjusting the
bearing assembly 90.
'~- 2197633
-25-
Referring now to FIGS. 3, 10, and 11, certain
other features of the fence assembly 22 will be
described.
Shown at 246 in FIG. 3 is an indicator
assembly comprising a hairline indicator
member 248 and indicator holder 250 that is bolted
on to the carriage 50 by bolt assemblies 252. The
indicator 248 is held underneath the indicator
holder 250 in a fixed location on the carriage 50.
By loosening the screw assemblies 252, the
indicator 248 may be removed from the holder 250
and its position on the carriage 50 adjusted. By
discerning a location of a hairline 254 relative
to the ruler 256, a distance between the abutment
surface 34 and the cutting line 32 may be
determined. The movement of the indicator
member 248 relative to the carriage 50 allows this
distance to be accurately calibrated.
Additionally, the hairline 254 is offset such that
a larger amount of adjustment can be obtained by
rotating the indicator 248 by 180~, if necessary.
Referring now to FIG. 10, shown therein is
the linkage assembly 160 and the jaw members 156
and 158. FIG. 10 shows that the linkage assembly
is connected by the pin 166 to flanges 256
extending upwardly from a mounting plate 258. The
mounting plate 258 is securely attached to the
carriage 50, preferably by the bolt assemblies 192
and 194 described above. Accordingly, FIG. 10
shows that the only direct connection between the
jaw members 156 and 158 and the carriage 50 is via
the pin 166 (but the jaw housings 190 and 244 will
2197633
-26-
engage the jaw members to prevent movement of the
carriages 50 and 52 relative to the jaw members).
Referring now to FIG. 11, the fence member 46
is shown to be basically rectangular in cross
section with a T-slot 260 formed on an upper side
thereof. FIG. 11 also shows that the tie rod 154
extends through the center of the fence member 46
as described above.
Referring now to FIGS. 12 and 13, depicted
therein at 320 is a locking system that may be
used in place of the locking system 48 described
above. The locking assembly 320 may be
substituted for the locking system 48 with only
one minor modification to the remaining components
of the fence assembly 22. Accordingly, the
discussion of the other components of the fence
assembly 42 will not be repeated herein, except to
the extent that certain of these components have
to be modified to incorporate the locking
system 320.
The locking system 320 comprises first and
second sections. These sections are essentially
identical in operation, and only one will be
described herein in detail.
Accordingly, shown in FIGS. 12 and 13 is the
first section 322 of the locking system 320. The
locking system 320 is shown in its open position
in FIG. 12 and in its closed position in FIG. 13.
As with the locking system 48 described above, the
locking system 320 grips the outwardly extending
flanges 78 and 86 by the rail members 38 and 40 to
lock the fence in a desired location. The locking
system 320 thus also does not rely on a large
- 2197633
horizontal locking force that is borne by the
support system 42 to fix the fence assembly 22 in
its desired location.
The first section 322 is interconnected with
the second section by a tie rod 324. The first
section 322 is mounted in the first carriage 50,
and the second section is mounted in the second
carriage 52. The tie rod 324 extends through the
center of the fence member 46 from the first
end 54 to the second end 56 of the fence
assembly 22.
The first section 322 comprises a jaw
member 326 and a linkage assembly 328 connected to
the actuator shaft 162. Movement of the actuator
shaft 162 acts on the jaw member 326 through the
linkage assembly 328 such that the jaw member 326
pinches the first rail flange 78 against a jaw
housing 330. This pinching action will lock the
first carriage 50 relative to the first rail 38.
More particularly, the linkage assembly 328
comprises: (a) a rocker plate 332 operatively
connected to the carriage 50 by a pivot pin 334;
and (b) a yoke assembly 336 attached to the pivot
plate 332 by a pin 338 and the jaw member 326 by a
pin 340.
Additionally, the jaw member 326 is pivotally
attached to the jaw housing 330 by a pin 342 such
that the jaw member 326 rotates in a vertical
plane that is substantially parallel to the fence
member 34.
Comparing FIGS. 12-13, it can be seen that
the actuator shaft 162 moves laterally between
first and second positions as described above.
2197633
-28-
The rocker plate 332 rotates between first and
second orientations corresponding to the first and
second positions of the actuator shaft 162 because
it is connected to the actuator shaft 162 by a
pin 344.
The rocker plate 332 is operatively connected
to the jaw member 326 by the yoke assembly 336 and
pins 338 and 340 such that the jaw member 326
rotates about the pin 342 between an unlocked
position as shown in FIG. 12 and a locked position
as shown in FIG. 13. In the unlocked position,
the gap 346 between an engaging surface 348 on the
jaw member 326 and an opposing surface 350 on the
jaw housing 330 is wider than the vertical
~;men~ion of the rail flange 78. Accordingly, the
carriage 350 is free to move when the jaw
member 326 is in the open position as shown in
FIG. 12.
In the closed position, the engaging
surface 348 rotates upwardly to pinch the
flange 78 against the opposing surface 350. This
locks the carriage 50 onto the first rail 38.
Shown at 352 in FIG. 12 in a somewhat exaggerated
manner is a space between the opposing surface 350
and the rail member 78 that exists when the jaw
member 326 is in the open position. This
space 352 should be large enough to prevent the
jaw housing 330 from interfering with the movement
of the carriage 350 when the locking system 320 is
in the unlocked position, but small enough such
that the jaw housing 330 does not travel
substantially when the locking system 320 is in
the locked position.
-- 2197633
-29-
In particular, this distance should be less
than approximately 20 thousandths of an inch to
provide sufficient clearance yet not place
excessive loads on the wheel members of the
suspension system when the locking system 320 is
locked.
From the foregoing, it should be clear that
the invention may be embodied in other specific
forms without departing from the spirit or
essential characteristics thereof. The present
embodiments are therefore to be considered in all
respects as illustrative and not restrictive.
