Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
This invention relates to an apparatus for selectively raising and lowering a
power tool
located beneath the working surface of a work bench and more particularly to a
gauge for
measuring the extent of upward and downward movement of a power tool beneath
the working
surface. The invention also relates to a dust collector for removing debris
such as saw dust,
wood chips and shavings and other debris which accumulates on the working
surface of a work
bench.
In U.S. patent no. 6,550,154 in which I am named as inventor, I describe an
apparatus for
selectively raising and lowering a power tool such as a muter and a rotary saw
mounted beneath
the working surface of a work bench. The apparatus has a carriage which is
located beneath the
working surface and on which the power tool is mounted. The cutting implement
of the power
tool projects above the surface and into a work piece. The implement may be a
bit, where the
power tool is a muter, or a blade where the power tool is a saw. The carriage
is raised and
lowered by means of a handle above the working surface. The handle is
removable so that once
the power tool is in a desired position, the handle is removed sc~ that it
does not interfere with the
routing or sawing operation. The subject matter of that patent is incorporated
into this application
by reference.
I have made improvements to the apparatus described in the patent referred to
above and
the subject matter of this application is directed to those improvements. One
improvement is the
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addition of a gauge for measuring the extent of upward and downward movement
or travel of the
power tool beneath the working surface. The gauge indicates how far the
carriage has travelled
up or down and serves as means for measuring any change in the level of the
carriage caused by
the handle.
Another improvement to which the subject application is directed is a dust
collector
mounted beneath the working surface and surrounding the bit o~r saw blade. The
dust collector
serves to remove debris such as sav~dust, wood chips, and shavings which is
generated during
routing or sawing and the dust collector so that the debris does not interfere
with such operations.
The dust collector is suitable for a<;e not only in conjunction with the
apparatus described in the
patent referred to above but in conjunction with any power tool mounted
beneath a working
surface.
SUIuIMARY ~F TIC 1NVENTI~N
The gauge of my invention is operatively connected to the apparatus for
raising and
lowering the carriage and measures the extent of alteration in th.e level of
the carriage. There is a
clutch for selectively connecting and disconnecting the gauge and the
apparatus such that when
the gauge is manually rotated, it is disconnected from the apparatus but when
the apparatus is
activated, the gauge is connected to it.
The dust collector includes a hollow chamber mounted beneath the working
surface of a
work bench and through which a cutting implement such as a bit or a rotary saw
extends. The
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dust collector includes vacuum means for withdrawing air from the chamber with
resulting
withdrawal of debris resulting from the cutting of a work piece on the working
surface.
DESCRIPTION OF THE DRAWINGS
The improvements of the subject application are described in detail with
reference to the
accompanying drawings in which:
Figure 1 is a perspective view of the working surface of a work bench in
conjunction with
a dial of the gauge of the invention;
Figure 2 is a perspective view of apparatus for adjusting the level of a power
tool attached
to the lower wall of the working surface together with a belt and block of the
gauge;
Figure 3 is a perspective view of the mechanism for adjusting the level of a
power tool as
described in the patent referred to above.
Figure 4 is an elevation of the working surface, carriage and dust collector
of the present
invention;
Figure 5 is an exploded perspective view of the gauge of the invention;
Figure 6 is a section of the gauge;
Figure 7 is a view of the lov~rer wall of the working surface in conjunction
with belts
which operatively interconnect the gauge, the apparatus for adjusting the
level of the power toal
and the carriage;
Figure S an elevation of the working surface, dust collector and carriage; and
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Figure 9 is a view of the lover wall of the dust collector, carriage, and
belts.
Like reference characters refer to like parts throughout the description of
the drawings.
DESCRIPTION OF THE PREFERRED EI~BOD1MENTS
With reference to Figure l, the gauge of the invention, indicated generally
10, includes a
circular dial 12 having a knurled outer edge 14. A scale is etched or painted
onto the upper
surface 16 of the dial and the dial is mounted in a recess 18 of a. plate 20
having an upper
working surface on which a piece of work or stock (not illustrated) is placed.
The plate has a first aperture, 22 through which an implement (not
illustrated) for cutting
the work piece extends. The cuttin4; implement may be a bit if the tool is a
router or a blade if the
tool is a saw.
With reference to Figures 1 and 3, the plate has a second aperture 24 through
which the
hexagonal stem 26 of a handle 28 extends. The stern extends into a block 30
which is attached to
the lower wall of the plate. A tube 32 is rotatably mounted in the block and
has a central
hexagonal opening which receives the stem. The outer wall of the hexagonal
stem frictionally
mates with the tube opening so that rotation of the handle causc;s a like
rotation of the tube.
The tube forms the hub of a gear wheel 36. As illustrated in Figures 2, 3 and
4, a belt 38
having teeth on its inner wall is trained around the gear wheel and around a
second gear wheel
40. The latter gear wheel is keyed to a spindle 42 which is threa.dably
received in an opening in
carriage 44.
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The carriage is part of a level adjusting apparatus and is described in the
patent referred to
above. A cutting tool such as a rouf:er or saw is clamped to the level
adjusting apparatus and, as
described in that patent the level adjusting apparatus is raised toward the
plate or is lowered away
from it by rotation of handle 28. As the handle rotates, so too do gear wheels
36, 40 with result-
ing rotation of spindle 42 and corresponding upward or downward movement of
the carriage.
With reference to Figures 5 and 6, the gauge includes a cover 50 which is
attached to the
working surface of plate 20 by means of screws 52. The cover i,s not shown in
Figure 1 since it
obscures most of the dial. When the cover is attached, its upper surface is
flush with the working
surface of the plate. The dial is thu~~ beneath the working surface.
A portion of the outer wall of the cover is curved to conform to the shape of
the outer
wall of recess 18. The remainder of the outer wall of the plate ins straight
and that portion is flush
with the side edge 20a of the plate when the cover is attached to the plate. A
mark or pointer 54
is painted or etched on the plate adjacent to the straight portion. and that
mark cooperates with the
scale on the dial in the manner described below.
As previously indicated, dial 12 is disposed in the recess beneath cover 50.
The dial is
attached to a cylinder 56 by means of a screw 58 which passes through a
circular opening in the
dial and into engagement with a threaded bore in the cylinder. A polymeric
gasket in the form of
an O-ring 60 is disposed between the dial and a gear wheel 70.
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The cylinder is received in a bearing 64 in a block 66 . The block is bolted
to the lower
wall of the plate by means of screws 68. Gear wheel 70 is attacihed to t:he
upper portion of
cylinder 56 by a threaded stud 72. An annular collar74 is attached to the
cylinder beneath the
block by the same means and serves to maintain the cylinder in the bearing. A
belt 76 having
teeth on its inner wall is trained around gear wheel 70.
With reference to Figures 6 and 7, gear wheel 70 is accommodated in a groove
78 in the
lower wall of the plate. Belt 76 likewise is accommodated in the groove. The
belt extends from
gear wheel 70 to a second gear wheel (not illustrated) which is keyed to an
axle mounted in bear-
ings in block 79. A third gear wheel 80 is also keyed to the axle. Belt 38
which is driven by the
handle is trained around the third gear wheel 80.
With reference to Figures 4 and 7, the level of cutting implement 82 is
adjusted by means
of handle 28. Rotation of the handle will cause belt 3 8 to turn spindle 42
with resulting raising or
lowering of carriage 44. The router or rotary saw on the carriage will
similarly ascend or descend
with corresponding raising or lowering of the bit or saw blade. Rotation of
the handle will also
cause a corresponding rotation of dial 12 since belt 38 causes belt 76 to
turn. The dial will indic-
ate how far the carriage has moved up or down.
The O-ring functions to produce a so-called "slip fit" or clutch between the
dial and gear
wheel 70. The pressure exerted on the O-ring by the dial and the gear wheel
ensures that the O-
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ring causes the two to move together when the handle is being rotated. If
however, the dial is
rotated manually, the O-ring will allow the dial to slip so that such movement
does not cause any
movement in the level of the carria~,re. Pressure on the O-ring by the dial
can be varied by
tightening and loosening screw 58 as illustrated in Figure 5 to ensure that
the O-ring operates in
this manner.
The O-ring acts as a clutch lbecause it operates to activate and deactivate
the connection
between the dial and the gear wheel. Rotation of the handle by :hand causes a
fike rotation of the
dial but rotation of the dial by hand does not cause the handle to rotate.
Rather, the handle
remains stationary when the dial is rotated manually and so too does the
carriage. This is because
the O-ring allows the dial to slip relative to the gear wheel.
In operation the gauge serves to measure the amount oi-.'travel of the
carriage, upward or
downward. To this end before the handle is moved, the dial is rotated by hand
until the pointer
indicates zero. Such rotation will cause no movement of the carriage or the
handle because of the
O-ring. The handle is then rotated manually to cause the carriage to move up
or down. Such
movement will cause a corresponding movement of the dial and the extent of the
movement will
be indicated by the pointer.
With reference to Figures l, 8 and 9, a dust collector , generally 84, is
attached to the
lower wall of plate 20. The cleaner includes a hollow chamber 86 which is
fastened to the lower
wall of the plate above the level adjusting apparatus. There is an opening 88
in the chamber
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through which the cutting implement &2 and tool extend. The dust collector has
a mouth 90
which surrounds the cutting impleiTient and into which saw dust:, wood chips
and shavings and
other debris 92 fall. The chamber has an exhaust port 93 to which a flexible
hose 94 is attached.
A fan (not illustrated) causes air to flow through the chamber in the
direction of the
arrows from the mouth to the exhaust port. Debris generated during routing or
sawing of a work
piece is carried outwardly of the chamber in the stream of air.
It will be understood, of course, that modifications can 1~e made in the gauge
and the dust
collector of the invention without departing from the scope and purview of the
invention as
defined in the claims which follow.
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