Note: Descriptions are shown in the official language in which they were submitted.
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FI131.D OF TIIB INVENTION
The present invention relates to an attachment
assembly for mounting to a conventional bench saw.
BACKGROUND OF TlI13 IN~NTION
Conventional bench saws comprise a base, a
work-supporting table resting over the base and
displaying a longitudinal opening therethrough, a movable
structure mounted in the base and carrying a power-
operated main shaft, a cutting tool operatively connected
to the shaft and protruding through the opening, and
means for causing vertical and angular displacements of
the shaft-carrying structure relative to the table.
The basic assembly of these bench saws is
accomplished at the manufacturing plant and their end use
i8 strictly limited to circular sawing.
United States patent No. 4,706,535 issued
November 17, 1987 to Ducharme proposes a scoring saw
assembly which can be installed on existing bench saws
which are not equipped with a scoring saw. Such
conventional bench saws are equipped with means for
causing vertical and angular displacements of the power-
operated shaft relative to the work-supporting table.
However, the scoring saw kit described in the above U.S.
patent comprises an elongated casing which is adapted for
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vertical displacement of the main saw blade relative to
the work table but which cannot be moved angularly with
the movable structure of the bench saw as the kit is
fixedly secured to the work-supporting table with means
allowing only the said vertical displacement. Hence, the
cutting operation on the work piece is limited only to a
vertical cut and to one type of cutting, namely scoring.
In applicant's co-pending Canadian application
serial no. 2,036,447 filed February 15, 1991, there is
described an attachment assembly for mounting to a
conventional bench saw which comprises an elongated tool-
holding member mounted to the power-driven main shaft of
the bench saw, the member having, at one end, a pair of
projecting rods adapted to engage a pair of guide pins
mounted on a movable part of the bench saw. The
positioning of the rods on the pins is accomplished
initially through a sliding engagement for the
installation stage until their engagement is finally
secured so that, during the cutting operation, rods and
pins cooperate to prevent lateral and angular movements
of the elongated member. In the embodiment illustrated
in the said patent application, the mounting and
dismounting of the elongated member are somewhat rendered
difficult and cumbersome by the particular engagement and
disengagement of the rods with their respective guide
pins.
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OBJECT8 AND ~TATEMENT OF T~E INVI!:~JTION
It is an object of the present invention to
provide an attachment assembly for mounting to a
conventional bench saw which overcomes the above mounting
and dismounting problems of the tool-holding member to
the bench saw.
It is thus an object of the present invention
to provide an attachment assembly for bench saws which
allows quick and easy installation and removal of the
attachment.
These objects are achieved by providing an
attachment assembly which comprises:
a rigid member associated with the tool and
mounted rotatively relative to the main shaft of the
bench saw, the member extending longitudinally of the
opening in the table and having projection means at one
end thereof; and
securing means mounted on the movable structure
of the bench saw to engage and disengage the projection
means; the securing means being movable between a first
position whereby the projection means are free from
engagement with the securing means, and a second position
whereby the member is fixedly connected to the movable
structure when the cutting tool is set for a cutting
operation to thereby prevent vertical, lateral and
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angular movements of the member caused by forces exerted
during the cutting operation.
In one form of the invention, the securing
means are spring biased from the first position to the
second position.
In another form of the invention, the
projection means consist of a pair of spring rods
longitudinally extending from one end of the member while
the securing means consist of a pair of guide pins on
which the rods are slidably received.
One advantage of the present invention is that
a scoring saw assembly may be mounted to the power-
operated main shaft of the bench saw, the scoring saw
assembly consisting of a main saw blade and a scoring saw
blade, both of which being vertically as well as
angularly adjustable relative to the work table while
permitting any movement (vertical, lateral and angular)
of the member during cutting operation. Vertical and
angular positioning is at all time possible with the
table handwheels; this is due to the positive action of
the rods between the pins.
Other objects and further scope of
applicability of the present invention will become
apparent from the detailed description given hereinafter.
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It should be understood, however, that this detailed
description, while indicating preferred embodiments of
the invention, is given by way of illustration only,
since various changes and modifications within the spirit
and scope of the invention will become apparent to those
skilled in the art.
BRIEF DF8CRIPTION OF THF DRAWING8
Figure 1 is a perspective view of a
conventional bench saw;
Figure 2 is an elevational view of one
embodiment of an attachment assembly made in accordance
with the present invention, adapted to be mounted to a
conventional bench saw and illustrating a scoring saw
assembly as an example of a cutting tool;
Figure 3 is an enlarged cross-sectional view
showing various positions of the spring biased plate;
Figure 4 is an elevational view showing the
projecting rods engaged in the pins of the attachment
a6sembly; and
Figure 5 is a side view of the components shown
in figure 4.
D~8CRIPTION OF PRFFgRRFD FMBODIMFNT8
Referring to figure 1, there is shown a
conventional bench saw, generally denoted 10, having a
base 12, a work-supporting table 14 mounted over the base
and displaying a longitudinal opening 16 through which
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protrudes a cutting tool, such as a blade saw 18. A
work-piece splitter 20 is pivotally mounted over the work
table. A pair of handwheels 22 and 24 are displayed
adjacent two side walls of the base 12: they serve to
vertically and tiltably displace and adjust the cutting
tool 18 relative to the work-supporting table 14. The
movable structure disposed within the bench saw to tilt
the tool as well as the mechanism which provides the
vertical adjustment of the tool are well known and a
detailed description thereof will not be given, although
parts thereof will be shown in figures 2 and 3 for an
understanding of the operation of the present invention.
Referring to figure 2, elements 26, 28 and 30
are parts of the movable structure conventionally found
in existing bench saws, with the exception that element
28 has a projecting wall 72, the function of which will
be described hereinbelow. Also standard in conventional
bench saws is a power-operated shaft 32 which is so
mounted on the movable structure as to allow vertical and
angular adjustments of the tool relative to the plane of
the work table 14.
Basically, the attachment assembly consists of
an elongated rigid member 36 which is mounted on the
power operated shaft 32. A detailed description of the
mounting of member 36 to shaft 32 may be found in
applicant's above mentioned Canadian application.
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Member 36 displays, at one end thereof, a pair
of spring rods 38 and 40 extending lengthwise of the
body. These rods are mounted to an end plate 42 of the
rigid member 36 by means of fastening nuts 44, 46 and 48.
Nut 44 together with bolt 49 secure plate 42 to member
36.
The attachment assembly also consists of a pair
of pins 50 and 52 which are fixedly mounted to a plate 51
pivotally mounted, through axis 57, to element 28 forming
part of the movable structure of the bench saw. This
element 28, which is also used for the mounting of the
splitter 20, is thus the only part of the conventional
bench saw which requires to be modified to embody the
present invention; indeed, a hole is pierced in this
plate to receive the axis 57.
Referring to figures 4 and 5, pin 52 is mounted
on a sleeve 70 contained between the lower part of plate
51 and an end wall 72 and over which is helically wound
a coil spring 74 having its opposite ends 76 and 78
respectively engaged in plate 51 and wall 72. This
spring 74 is tensioned so as to force plate 51 in the
inclined position shown in figure 4 wherein rods 38 and
40 are confined in the grooves of the respective pins 50
and 52.
2056147
In the embodiment illustrated in figure 2, the
attachment assembly is structured for a scoring saw
assembly which includes a main saw blade 53 mounted on
shaft 32, a scoring saw blade 54 mounted for rotation
about a fixed axis 56 and an idler-belt tensioning pulley
58 mounted for rotation about a fixed axis 60. The axes
56 and 60 are parallel to one another as well as to the
main shaft 32; these axes are defined by shafts mounted
at an end of the rigid member 36 which is opposite to the
end plate 42. An endless belt 62 transmits rotation from
a pulley 64 mounted on the main shaft 32 to the pulley 58
and engages an element 66 mounted on axis 56 for rotating
the scoring saw blade 54 in a direction opposite to that
of blade 53. The position of the axis of pulley 58 is
adjustable relative to the fixed axis 60 by appropriate
means, such an eccentric; to allow for elongation
variations in the belt 62.
To mount the attachment, the rigid member 36 is
placed on shaft 32 as well as nut 33; then, referring to
figure 3, member 36 is rotated in the direction of arrow
79. Plate 51 i8 then forced (or rotated
counterclockwise) manually against the action of spring
74 in the direction of arrow 80 until rod 40 rests on pin
52. Then, plate 51 is released whereas, under the action
of spring 74, plate 51 rotates cloc~wise to reach the
inclined position of figure 4 wherein pin 50 applies
downward contact pressure on rod 38. The tension in the
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g
spring must be sufficient to securely maintain the rigid
member in fixed condition during a cutting operation.
The rigid member 36 is therefore fixed at three
points of contact: on shaft 32, on pin 50 and on pin 52.
However, the configuration of the rods and that of the
grooved pins is such as to enable a sliding cooperation
therebetween.
To dismount the attachment, the reverse
operation is carried out.
Although the invention has been described above
in relation to a specific form, it will be evident to a
person skilled in the art that it may be modified and
refined in various ways. For example, the attachment
assembly may also be used with other types of cutting
tools, such as a milled cutter, a jig saw, a press drill,
etc. as illustrated in applicant's above mentioned
Canadian patent application. It is therefore wished to
have it understood that the present invention should not
be limited in scope, except by the terms of the following
claims.
