Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD OF THE INVENTION
This invention relates to a guide for facilitating the adjustment of a piece
of stock on a
work bench and more particularly to a guide for adjusting the position of a
piece of stock on a
work bench in order to control the angle of cut into the stock by a power
tool. The power tool
may be a router, a power saw and the like.
BACKGROUND OF THE INVENTION
A piece of stock which is cut on a work bench usually contacts a fence along
one of its
sides. Along its oppositely facing side, the stock contacts a guide which
serves to control the
movement of the stock across the working surface. The guide is usually fitted
with a tongue
which slides in a groove. The groove conventionally extends laterally across
the working surface.
By means of the tongue, the stock can travel on a path which is parallel to
the groove.
Many problems are encountered in controlling the stock in this manner. For the
tongue to
move smoothly in the groove, it cannot be too tight-fitting. The looser it is,
however, the more
subject the tongue is to vibration or oscillation. Such movement causes a like
movement of the
guide with a resulting loss in precision of the cut made by the power tool.
Such movement also
causes fatigue since the operator will feel the movement when his hands are on
the guide.
Another problem which is frequently encountered is that the stock tends to
bind in the
cutter of the power tool as the stock is being moved across the working
surface. The reason is
that the groove in which the tongue of the guide travels is spaced apart from
the cutter a signif
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icant distance to prevent it from interfering with the cutting operation. The
guide, being attached
to the tongue, is spaced apart an equal distance. The further the guide is
from the point at which
the stock is cut, the less effective it is in preventing unintended movement
of the stock at that
point. Such movement is usually the cause of binding.
A further problem is that as the cutter rotates, it urges the stock away from
the fence and
toward the guide. Because of the significant spacing between the cutter and
the guide, the stock is
diWcult to control and unintended movement of the stock may occur.
SUNI1VIARY OF THE INVENTION
I have invented a guide for controlling a piece of stock in a way that
substantially
overcomes these problems. The guide does not move in a groove but moves along
a guide rod.
Very little if any vibration or oscillation occurs as the guide moves.
Moreover, the guide can be
moved until it is very close to the cutter. In fact it can be moved over the
cutter. Being so close,
very little if any unintended movement of the stock occurs as it is being cut.
A further advantage of my guide is that as the stock is being cut, the cutter
urges the stock
into the fence and not into the guide. Since a fence is stationary during
cutting, very little
unintended movement of the stock is caused by the cutter.
The guide of my invention controls the angle of stock on a work bench equipped
with a
fence. Briefly, the guide includes: a base and a slider connected to the base
and movable along
the fence. A rotary element is mounted for rotation to the base and a backing
block is mounted to
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the rotary element for supporting the stock while it is on the working
surface. There is means for
releasably clamping the rotary element to the base to prevent the rotary
element from rotating
relative to the base.
DESCRIPTION OF THE DRAWINGS
The guide is described with reference to the accompanying drawings in which:
Figure 1 is a perspective view of the guide in conjunction with a work bench
and a fence;
Figure 2 is an exploded perspective view of the components of the guide;
Figure 3 is a plan view of the guide, work bench and fence;
Figure 4 is another plan view of the same components as is Figure 3;
Figure 5 is a perspective view of a second embodiment of the base and rotary
plate;
Figure 6 is an exploded perspective view of the base and rotary plate;
Figure 7 is an exploded perspective view of the lower wall of the rotary plate
together
with an insert attached to the lower wall;
Figure 8 is an elevation, partly in section, of the insert;
Figure 9 is a section, in enlarged scale, of a portion of the insert;
Figure 10 is a perspective view of the base;
Figure 11 is a section of the insert and base in which a detent is engaged;
and
Figure 12 is another section of the insert and base in which the detent is
disengaged.
Like reference characters refer to like parts throughout the description of
the drawings.
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DESCRIPTION OF PREFERRED EMBODIMENTS
With reference to Figures 1 and 3, the guide of the invention, generally 10,
is mounted to
a fence 11 which is mounted in grooves l2a,b at opposite sides of the working
surface 14 of a
work bench. Knobs 16 are each end of the fence are provided for locking the
fence in grooves
l2a,b so that the fence is stationary. The structure of the fence and the way
in which it operates
are conventional
A circular opening 18 is formed in the working surface through which the
cutter (not
illustrated) of a conventional power tool extends. The cutter may be a bit of
a router or the blade
of a power saw. The power tool, whether a router or a power saw, is mounted
beneath the
working surface.
A guide rod 20 is supported above the fence by brackets 22a,b which are
attached to the
rear wall of the fence. The guide rod extends horizontally along the length of
the fence and
supports a slider, generally 24. The slider has a sliding tube 26 having an
internal passageway in
which the guide rod is received. The sliding tube is freely slidable along the
guide rod.
A stop 27 for the slider is mounted for sliding along the guide rod. With
reference to
Figure 3, the stop is composed of a ring 28 which encircles the guide rod and
an adjusting screw
29 which passes through a threaded opening in the ring and into contact with
the guide rod.
Tightening of the screw into contact with the rod immobilizes the stop in the
conventional
manner. The stop serves to limit the length of travel of the slider.
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As illustrated in Figure 2, the slider has a pair of spaced blocks 30a,b
ai~xed to tube 26.
The blocks rest on the upper edge of the fence as the tube slides along the
guide rod. The blocks
are connected to a side wall 32 which extends vertically downwardly and
terminate at a base 34.
The base extends horizontally outward from the side wall.
The base supports a rotary plate or element 36. The plate has an outer edge
which is
curved in part and otherwise is straight. The plate has an opening 38 for
receipt of a fastener
composed of threadably interconnected stud 40 and pin 42. The fastener serves
to interconnect
the plate and base so that the plate is rotatable relative to the base.
An upstanding rail 44 is attached to the plate adjacent to to the straight
part of the plate.
The rail is connected to a backing block 48 by means of twoor more pairs of
threadably inter-
connected studs 50 and nuts 52. The nuts are received in a groove 56 in the
backing block.
The groove has an interior large enough to allow the nuts to slide freely but
the front
opening of the groove is constricted so that the nuts cannot pass through the
opening. The nuts
thus hold the block to the rail but allow the block to slide relative to it.
If, however, the studs are
tightened to the nuts, the nuts will frictionally engage the walls of the
groove which define the
opening. The nuts will then prevent the block from sliding.
When the rail is attached to the backing block, the downwardly facing lower
wall of plate
34 is preferably spaced above the working surface 14 of the work bench. As
such, the operation
of the plate will not be impeded by dust, sawdust and chips which collect on
the working surface.
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More preferably, the lower plate wall is spaced above the cutter of the power
tool so that the
cutter will not damage the plate when the plate moves over the cutter
A scale 60 is etched or painted onto the upper surface of the plate adjacent
to its curved
edge. The scale acts as a gauge to measure the angle of the plate relative to
some line of
reference. In Figure l, the line of reference is on the plane of the front
wall 11 a of the fence.
Since the plate is connected to the backing block, the gauge serves to measure
the angle between
the front wall 48a of the block against which the stock is placed, and the
front wall 11 a of the
fence.
An arcuate groove 64 is formed in the plate. A handle 66 has at its lower end
a threaded
shank 68 which passes through the groove and into a threaded aperture 70 in
the base. The
handle serves as means for releasably clamping the plate to the base so that
the position of the
plate on the block is adjustable. Thus, by means of the handle, the piece of
stock may be clamped
in a fixed angular position relative to the fence.
The operation of the adjusting guide of the invention is as follows: With
reference first to
Figure 3, a piece of stock 72 is shown resting against backing block 48. The
angle of the stock is
adjusted by loosening handle 66 so that plate 36 can be rotated. Once the
stock is in the desired
position, the handle is tightened so that the plate is immovable relative to
the base. The stock can
then be moved laterally in the direction of arrow 76 by applying pressure to
the adjusting guide to
cause sliding tube 26 to slide along the guide rod in that direction. As the
stock moves over open-
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ing 18, it is cut by the cutter.
The stock can be moved longitudinally forward in the direction of arrow 78 by
loosening
knobs 16 to allow the fence to carry the guide forward.
When the cutting operation is complete, the guide can be moved out of the way
by lifting
handle 66. By so doing, the base and plate will rise and tube 26 will rotate
about guide rod 20.
Further lifting of the handle will cause the guide to swing over the fence and
away from the
working surface where it will not hinder any operation being carried out on
the surface.
With reference to Figure 4, the angle of the fence can be adjusted by knobs 16
to allow
for greater flexibility in the path of the guide.
With reference to Figures 5 and 6, blocks 80a,b attached to slider 82 are
connected to side
wall 84 by means of four socket head cap screws 86. The side wall is connected
to base 88 as is
rotary plate 90 by means of bolt 91 which allows the plate to swivel on the
base. Handle 92
travels in arcuate groove 93 in the rotary plate and serves to releasably
tighten the rotary plate to
the base to prevent the plate from swivelling. Handle 66 and groove 64 in the
previous drawings
serve the same purpose.
Fixed to the upper wall of the rotary plate is a clamp 94. The clamp serves to
attach rail
96 to the rotary plate and to prevent it from sliding relative to the plate.
It does so by the
following means. The rail has a T-slot 98 for sliding receipt of an elongated
flat bar (not
illustrated). The bar has threaded openings for receipt of threaded stems
attached to knobs 100.
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Rotation of the knobs in one direction causes the bar to rise into frictional
contact with the upper
wall of the T-slot and thereby immobilize the rail relative to the rotary
plate. Rotation of the
knobs in the opposite direction causes the bar to descend thereby allowing the
bar to slide in the
T-slot.
The rail is bolted to backing block 102. The block is movable in three ways.
It is movable
forward and back, it swivels clockwise and counterclockwise, and it slides to
the right and to the
left. The first movement occurs when slider 82 moves on the guide rod as
previously described.
The second movement occurs when handle 92 is loosened to allow the rotary
plate to swivel
about bolt 91. The third movement occurs when clamp 94 is loosened.
With reference to Figures 6 and 7, base 88 has a generally U-shaped opening
104 in its
outer edge for receipt of the raised central area 106a of an insert 106. The
two outer areas 106b,c
of the insert are inset into the lower wall of the base and each has a slot
for receipt of bolts 108
for attachment of the insert to the base. Outer area 106c has a scale 110
which projects beyond
the outer edge of the base to permit fine adjustment of the rotary plate.
The central area of the insert has inner and outer holes I 12, 114 formed in
it. The outer
hole has a cylindrical wall defined. at the top by a raised annular lip 116.
The lower portion of
the hole receives a metallic ball or ball bearing118, and immediately below
it, a coil spring 120.
The ball rests on the spring and is urged upwardly by the bias of the spring.
The inner hole 122 in the insert has a threaded inner wall for threadable
receipt of a pin
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124 for pivotally attaching a detent-disengaging plate 126 to the insert. A
threaded locking key
128 holds the pin in position.
With reference to Figures 8 and 9, plate 126 has a slot 130 which when above
the ball as
illustrated in Figure 8, allows the upper wall of the ball to extend above the
plate. The edges of
the slot are spaced apart less than the diameter of the ball to prevent the
spring from pushing the
ball upwardly out of the slot.
With reference to Figure 9, when the detent-engaging plate pivots in the
direction of the
arrow, the slot is no longer above the ball and the plate forces the ball
downward into the opening
in the plate. The ball, accordingly, no longer projects above the plate.
A cavity 140 is formed in the lower wall of the plate. The side walls of the
cavity engage
annular lip 116 when the slot is over the ball as illustrated in Figure 8 and
entirely over the ball
as illustrated in Figure 9. The lip as such acts as stop points for the detent-
engaging plate and
ensures that the plate, while free to pivot, never pivots beyond the central
area of the insert.
Being always over the central area, the plate serves to confine the ball in
hole 114.
The ball cooperates with the rotary plate and together they act as a detent to
cause the
rotary plate to swivel in predetermined increments on the base. Figures 10 -
12 illustrate the way
in which the ball and plate cooperate in this way. With reference first to
Figure 10, the detent-
engaging plate 126 is marked with the words "on" and "ofd'. Those words
indicate when the
detent is engaged and when it is disengaged. When engaged, slot 130 is over
the ball and the ball
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projects above the plate 126. When disengaged, the ball is confined below the
plate.
With reference to Figures 7 and 11, arranged along an arc-shaped line 142-142
on the
lower wall of the rotary plate 90 and spaced radially outwardly from arcuate
groove 64 is a
number of dome-shaped openings 146. The openings are spaced an equal distance
apart from one
other.
When the detent is engaged as illustrated in Figure 11, the ball is received
in one of the
openings 146. As the rotary plate swivels, the ball rolls out of that opening
and rolls into the next
on the arc. The ball therefore causes the rotary plate to move in fixed
increments since when the
ball is between each opening, the plate rolls on the ball and is unstable. The
plate will eventually
swivel to a point at which the ball finds its way into an opening
When the detent is disengaged as illustrated in Figure 12, the ball is below
openings 146
and does not interfere with the movement of the rotary plate. At this time,
the position of the
rotary plate can be accurately set by means of scale 110. Handle 92 can then
be tightened into
engagement with the rotary plate in order to hold the plate in the desired
position.
It will be understood, of course, that modifications can be made in the
structure of the
guide which is described herein without departing from the scope of the
invention.
