Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
PORTABLE SAWING DEVICE UTILIZING A CIRCULAR POWER SAW
This invention rela-tes to a portable sawing device adapted
to be detachably fastened to a workpiece support bench and to
utilize a portable circular power saw which is supported at
the forward part of a horizontal arm and is mutually recip~
rocated with the arm to traverse a workpiece positioned on
the bench and effect a cut.
BACKGROUND OF T~E INVENTION
~lthough a variety of devices are available for executing
la-teral and longitudinal cuts on workpieces (some of which
utilize portable power saws) generally such devices have a
frame or base attached to a support stand having a plurality
of supporting legs. A small, essentially rectangular platform
is afixed to the frame or base defining a workpiece support
surface. An arm or saw guide is usually secured by a support
means to the frame and is disposed over the workpiece support
surface. While the saw is usually slidable along the arm or
saw guide, it is, generally, in some way permanently attached
- to it and forms an integral part of the device. This combina-
tion of components makes such devices bulky, heavy, difficult
to move and awkward to transport. Furthermore, the relatively
small workpiece support platforms of such devices do not con-
veniently lend themselves to extension. It is desirable,
however, when cutting an elongated workpiece, to have an ex-
tended surface supporting such a workpiece over its entirelength to prevent it from jackknifing and to keep the ends
from fallina when cut. Such an extended workpiece support
surface, by means of markings on it, may also serve as a guage
to ~uickly measure the desired lengths to be cut. Moreover,
once the workpiece support platform of such a prior art device
is extended, the device is then more or less attached to the
extension and is inconvenient to move.
In addition, it is a known characteristic of such a com-
monly used sawing device as the s-tandard fixed arm radial arm
saw, that a cut is executed with it by drawing the saw for-
wardly across the workpiece. Because of -the direc-tion of
S the saw blade rotation, the saw has the objectionable ten-
dency to feed itself, climb the workpiece and jamb, thus
stalling the motor, so that considerable care and effort mus-t
be exercised when executing a cut. Additional care must be
taken, upon completion of a cut, to return the saw along the
kerf to its rearward position to permit the safe removal,
replacement and positioning of the workpiece. I'he fixed arm,
however, remains over the workpiece silpport surface more or
less in the way of the operator.
The objects of the present invention are, therefore, to
provide a sawing device which is of light weight and easily
portable and which is convenient to se-t up and use in con-
junction with a simply constructed, extended workpiece suppor-t
bench; a device which utilizes a conventional portable circular
~ power saw which may be easily mounted on, and removed from it,
thus reducing the weight of the device for portability and
also eliminating duplication by permi-tting the use of the
same saw for other purposes; a sawing device in which the saw
may be mutually reciprocated with the support arm and also be
pivotably attached to it so that the saw may be drawn for-
wardly above the workpiece, then plunged down and pushedrearwardly into the cut, thereby eliminating self-feeding. It
may then be tilted upwardly out of the way to clear the work
area for removal, placement and positioning of the workpiece.
It is, of course, desirable to provide on such a sawing
device means for automatically retracting the saw blade guard
as the saw is lowered into a cut and for permitting the guard
to return around the saw blade as the saw is til-ted upwardly.
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It is also an object oE the present invention to provide a
sawing device, with the aforementioned features, which is
sufficiently versatile to perform all desirable cuts, uncom-
plicated to manufacture and use, sturdily construc-ted, dura-
ble, yet sufficiently compac-t to be convenient to transport.
SVMMARY OF THE INVENTION
The apparatus of a preferred embodiment of the present
invention is adapted to func-tion in conjunction with an ex-
-tended workpiece support bench, construc-ted of wood, defin-
ing a workpiece support surface. Such a bench may be of anydesirable length necessary to accommodate the workpiece and
may be supported by any suitable means, as by a plurality of
legs or as by sawhorses at each end. It should have a reason-
ably broad horizontal surface to provide an adequate work area
and a flange, extending along the rearward edge and projecting
above the top surface, defining a workpiece abutting fence.
The apparatus includes a frame comprising an extended flange
member L-shaped in section and secured across the broader
~ part of the face of an oblong tapered plate member at a right
angle to its longitudinal axis -forming a T-shape. Clamping
means are provided at the extremities of the frame for detach-
ably fastening it against the underside of the workpiece
support bench. The extended flange member aligns with the
lower rearward edge of the bench, with the L-shape conforming
to the surfaces, and the tapered part of the plate member
extends forwardly and flatly against the underside of the
bench. The clamping means at the ends of the extended flange
member extend upwardly and forwardly so that the tightening
screws bear on the top edge of the fence. The forwardly ex-
tending part of the tapered frame plate member has an extend-
able section attached to it with an upwardly turned part
threadably receiving a horizontal tightening screw bearing
against -the forward edge of the bench. By these means -the
apparatus of this invention may be easily and quickly attached
to, and removed from, the support bench.
The apparatus is adapted to utilize a conventional portable
circular power saw which is mounted on and engaged by an
adapter pla-te designed to conform to the saw base or planar
shoe and hold it securely in place. The saw is locked in
position by its own weight and may be removed only by tilting
it upwardly about the toe of the planar shoe and lifting i-t
off. Holes in the adapter plate are provided for securing
the saw by means of screws when desirable.
The adapter plate is hinged to a rotatable bearing plate
which is lockably attached by a pivot bolt beneath a fixed
bearing plate which is secured to the underside of the for-
ward part of a horizontal support arm forwardly disposed above
the workpiece support bench. The saw with the adapter plate
is thus pivotably movable about the horizontal hinge axis
between a lowered, horizontal, cutting position generally
~ spaced from and parallel to the workpiece support surface
and a raised, non-cutting, tilted-up position. By means of
a tension spring acting on a lever attached to the adapter
plate, the plate and saw are yieldingly urged upwardly and
maintained in the tilted-up position unless forced down for
the execu-tion of a cut.
In order to leave the workpiece support surface unobstruc-
ted the saw and support arm of this invention reciprocate as
a unit. This necessitates a comparatively frictionless sup-
porting of the arm and the need to eliminate the tendency of
the arm -to sag and bind under the overhanging weight of the
saw. In addition, the mounting means must be such as to pre-
vent twisting, sidesway, and chattering of the arm as it is
reciprocated. This is accomplished in this invention by a
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novel carriage arrangement wherein the sliding components
are located beneath the frame and workpiece support bench.
These components comprise two horizontal, parallel, spaced
apart, extended rods slidably mounted in sleeves secured to
a horizontal mounting pla-te, rotatably and lockably attached
by a vertical pivot bolt and lock nut, to the frame underside.
Front and rear cross members are rigidly secured to the ends
of the rods and the saw supporting arm is cantilevered for
wardly from the top of a vertical support column which
extends upwardly from the rear cross member. By this ar-
rangement -the weight of the saw is more or less balanced over
the sliding rods -thus eliminating the binding and chattering
normally caused by the torgue of a laterally disposed weight.
The support arm carriage may be rotated about the vertical
axis of the pivot bolt and locked in place to align -the arm
and saw along desired cutting angles to the longi-tudinal axis
of the workpiece support bench.
The saw supporting arm comprises two concentric, telescoped
cylinders. I'he inner cylinder is rotatable within the outer
cylinder, extends forwardly beyond it and has the saw sup-
porting means attached to it. The rearward end of the outer
cylinder is secured to the support column and the forward
end terminates in a split collar bearing with a tightening
screw for releasably securing the inner cylinder from rota-
tion. By this means, the hinge axis, adapter plate, and sawmay be rotated about the horizontal central axis of the sup-
port arm and locked at desired bevel cutting angles.
The adapter plate and saw may be turned in conjunction with
the rotatable bearing plate to a rip cutting position perpen-
dicular to the supporting arm and restrained in the loweredcutting position by a flange on an ear projecting horizon-
tally from the fixed bearing plate.
The foregoing features and other advantages will readily
become apparent as the preferred embodiment of this inven-
tion is, hereinafter, more fully described in detail, illus-
trated in the accompanying drawings and finally poin-ted out
in the appended claims.
In the claims, ~e well as in the descrip-tion, parts are,
at times, identified by specific names for claxity and con-
venience, but such nomenclature is -to be understood as having
the broadest meaning consistent with the context and concept
of this invention. Yor ease of description and understanding,
the apparatus of this invention will be referred to in the
normal operating position in such terms as upper, lower,
horizontal, vertical, forward and rearward. It is to be
understood, however, that these are relative -terms and that
the apparatus of this invention may be manufactured, trans-
ported, stored, sold, and used in an orientation o-ther than
the normal operating position. The precise shapes and sizes
of the components herein described are not essential to this
invention unless otherwise stated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, illustrating the preferred
embodiment of -this invention, like characters designa-te
corresponding like parts in all views.
FIG. 1 is a perspective front-side view of -the apparatus
of the present invention, attached to a suitable workpiece
support bench, with a portable circular power saw mounted
thereon in a non-cutting position.
FIG. 2 is a side elevation, partly in section, of the appa-
ratus illustrated in FIG. 1, but showing the saw in a forward
and fully lowered position cutting a workpiece on the bench.
FIG. 3 is a -top plan view of the apparatus shown in FIG. 2,
but with the apparatus set in an angle cutting position.
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FIG. 4 is a view similar to FIG. 3, but with the apparatus
set for rip cut-ting with the saw turned -through 90 degrees
and locked in a horizontal position.
FIG. 5 is a bottom view of the apparatus shown in FIG. 2.
FIG. 6 shows the apparatus of this invention removed from
the workpiece support bench, with the saw removed, and the
apparatus folded for carrying or storage.
FIG. 7 is an enlarged perspective view of the saw adapter
plate of -the embodiment of lhis invention, and of a typical
portable circular saw assembly utilized by this invention,
illustrating the engagement of the saw planar shoe and the
alignment of the mounting screw holea.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As illustrated in the drawings, FIGS. 1 to 5, the apparatus
of this invention, designated generally by the numeral 10, is
designed to be attached to, and function in conjunction with,
a suitable workpiece support bench constructed of wood, desig-
nated generally by the numeral 11, providing a workpiece sup-
port surface 12 upon which a workpiece 13 may be positioned.
Such a bench should have a reasonably broad horizontal sec-
tion 14, with a narrower section forming a workpiece abutting
or rip fence 15 secured to it, as by nails, along the rearward
edge flush with the bottom surface and projecting slightly
above the top surface 12. The bench 11 may be of any desir-
able length necessary to accommodate the workpiece and may
be supported by any suitable means as by a plurality of legs
or sawhorses at each end (not shown).
The apparatus of this invention is adapted to accommodate
and utilize most types of conventional portable circular
power saws that are commercially available in the United
States and Canada. One such type of saw is designated generally
by the numeral 16 in FIGS. 1,2, 3,4 & 7. Typically such saws
are an assembly comprised of, in part, a handle 17, a trigger
switch 18, a power supply cord 19, a circular saw blade 20,
a fixed upper saw blade guard 21, a spring biased, movable,
lower saw blade guard 22, a lower saw blade guard operating
lever 23, a bevel cut-ting angle adjustment knob 24, a bevel
angle guage 25, a cutting depth adjustment knob 26, a base
plate or planar shoe 27, a planar shoe mounting bracket 28
(FIG. 7), and planar shoe mounting screws 30 (FIG. 7). The
planar shoe 27, as shown in FIG. 7, generally has a slightly
0 tUrrled Up toe 31, a saw blade slot 32, and a cutting guide
notch 33.
As best illustrated in FIG. 6, the apparatus 10 includes
an essentially T-shaped frame, designated generally by the
numeral 36, horizontally disposed and comprised of an extended
flange 37, corresponding to the top of the T-shape and se-
cured, as by welding, across the broad face of an oblong
tapered frame plate 38~ The forwardly extending tapered part
of plate 38 corresponds to the stem of the T-shape, so that
the longitudinal axis of plate 38 is perpendicular to the
longitudinal axis of the flange 37. The horizontal flange
37 is L-shaped in section and one edge is upwardly disposed~
and the other, which is forwardly disposed, is cut out to con-
form to the shape of plate 38 so as to form a flush joi.nt of
the two surfaces. An arcuately shaped portion of the broad
face of plate 38, which extends rearwardly beyond the flange 37
and has angle indicia 39 along the arcuate edge, forms the
protractor plate 40. The narrow forward end of frame plate 38
has a plurality of symmetrically spaced, threaded, screw
holes 41, corresponding to equally symmetrically spaced holes
in an extension plate 42 secured to it by screws 43 (FIGS. 2
5). The forward end of extension plate 42 has a thickened
upwardly turned part 44, in which ls threadably received
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a horizontal tightening screw and knob 45 with a swivel base
46, knurled on the rearward face, for securing this part of
the frame 36 to the forward edge of the bench section 14,
as will be hereinafter descxibed. The ends of the flange 37
have secured thereto, as by welding, upwardly disposed
brackets with the upper ends thickened and turned forward-
ly forming C-clamps 47 (FIG. 1). Vertical tightening screws
and knobs 48, with swivel bases 49, are threadably received
in the forwardly turned sections of clamps 47.
sy the novel design of frame 36 thus far described, the
frame 36 may be attached to the workpiece support bench
11 by passing the frame plate 38 forwardly beneath bench
11 and hooking clamps 47 on -the fence 15 so that the swiv-
el bases 49 bear on the top edge of the fence 15, and the
flange 37 aligns longitudinally with the bot-tom rearward
edge of the fence 15 and conforms thereto. The forward end
of extension plate 42 i6 then brought upwardly so tha-t the
swivel base 46 bears against the forward edge of bench section
14 as the screw and knob 45 is tightened and the frame plate
38 is held flatly against the bottom of the bench 11. Screws
48 on clamps 47 may then be tightened and screw 45 may be
further tightened to set the frame 36 in close contact and
conformity with the underside and the rearward edge of the
bench 11. Extension plate 42 may be adjusted for various
widths of bench section 14 by selecting the appropriate screw
holes 41 provided for attaching it to the frame plate 38.
The frame 36 may be detached from the bench 11 by reversing
-the above proceduxe.
The description henceforth will be based on the under-
standing that the frame 36 is secured to the bench 11 and
that the work support surface 12 is horizontally disposed.
Projecting downwardly from, and secured by welding to, the
52~
underside of frame plate 38 is a vertical pivot bolt 50, at
a location such that its vertical axis coincides wi-th the
intersec-tion point of the longitudinal axis of plate 38 and
the join-t ]ine of bench sections 14 and 15. (FIG. 6)
Rotatably mounted on pivot bolt 50, flatly disposed against
the underside of plate 38 and extending slightly beyond the
rearward edge of plate 40, is a rectangular plate 51, lock-
able in fixed relation to plate 3% be means of a washer 52
and lock nut 53 threaded on pivot bolt 50 (FIG. 5).
Two parallel tubular sleeves 54 are secured by welding to
mounting bases 55 which are, in turn, secured as by we].ding
to the underside of rectangu].ar pla-te 51, along its opposite
parallel edges (FIGS. 1 and 5). The open ends of tubular
sleeves 54 are fi.tted with friction reducing bushings 56,
and slidably mounted therethrough are two extended, equal
length, round, parallel rods 58. The ends of the rods 58
have a reduced diameter and are spanned by two equal length,
parallel, transversely extending cross members, a forward
cross member 59 and a rear cross member 60. The ends of.
rods 58 are snugly fitted into holes provided at the ends
of the cross members 59 and 60 and are rigidly secured
thereto by lock nuts 61 threaded on the rod ends, thus main-
taining the parallelism of the rods and cross members. The
rods 58 being considerably longer than the mounting sleeves
54 are thus slidable within the bushings 56, forwardly and
rearwardly, within the limi.ts of the cross members.
It is desirable -to be able to.releasably lock the rods 58
against slidability, for reasons to be pointed out further
on in this descrip-tion. To this end, a rectangular aperture
is provided in the side wall of sleeve 54 within which is
fitted a rectangular semi-circular braking block 62 (FIG. 2
The inner face of block 62 is curved to conform to the rod
-- 10 --
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58 and the outer face to conform -to the outer curvature of
the sleeve 54. A rectangular seml-circular cover plate 63
is welded over the aperture. A set screw 64, with a finger
knob, is threadably received in cover plate 63, perpendicu-
larly to the longi-tudinal axis of the rod 58 and bears on
braking block 62, which in turn, upon -the tightening of the
screw 64, bears against the rod 58, thus securing it from
reciprocatory movement relative to the sleeve 54 (FIG. 2).
The rods 58, in conjunction wi-th plate 51, may be rotated
in a horizontal plane about the vertical axis of pivot bolt
50 and locked by means of lock nut 53 at selected angles
to the longitudinal axis of the bench 11. It is, of course,
desirable that this angular adjustment be known, and for this
purpose the rearward edge of arcuate plate 40 is the arc
of a circle having its center at the ver-tical axis of pivot
bolt 50. The 90 degree mark of the angle indicia 39 is lo-
cated on the longitudinal axis of frame plate 38. An indented
l.ine, provided on plate 51, serves as an angle indicator 65.
When the longitudinal axes of the rods 58 are parallel to the
longitudinal axis of frame plate 38 and thus at a 90 degree
angle to the longitudinal axes of the fence 15 and the work-
piece 13 thereagainst, the indented line indicator 65 aligns
with the 90 degree mark of the indicia 39 on plate 40 (FIG. 1).
For quickly locating this position, a tapered aperture
(not visible) is provided through plates 40 and 51 receiving
a tapered locating pin 66, biased downwardly by spring 71
and slidably journalled in, and held vertical by, bracket 67.
as shown in FIG. 1. Tapered apertures (not visible) are
also provided in plate 51 for engaging locating pin 66 at
45 degree positions both sides of center.
For ease of further description, the rods 58 will be
considered as being temporarily locked in a position such
~ ~:15~9~
that their longitudinal axes form a 90 degree angle with
the longitudinal. axes of the bench 11 and workpiece 13.
The rear cross member 60 has a vertical channel 68, at
proximately the mid-point of the rearward face, slidably
and snugly receiving the flattened lower end of a vertical
support column 69. A carriage bolt 70 passes -through an
elongated vertical slot (not visible) in the middle of channel
68 and through a corresponding bore in the flat-tened part of
column 69. The column 69 may thus be adjusted upwardly or
downwardl.y within the limits of the elongated slot and locked
rigidly to cross member 60 by a lock nut 72 threaded on
carriaye bolt 70 (FIG. 2).
Secured, as by welding, to the upper end of support col-
umn 69 and cantilevered forwardly over bench 11, is a cy-
lindrical arm 73, having its rearward end closed by column 69and its forward terminating in a collar bearing 74, longi-
tudinally split at the top and provided wi-th a horizontal
clamping screw and knob 75 (FIGS. 1 and 2). A second con-
centric inner cylinder 76 is snugly telescoped into the
full length of arm 73, extends forwardly beyond it, and is
rotatable therein, a predetermined amount, about -their com-
mon central longitudinal axis which is, by design, parallel to
the longitudinal axes of the rods 58.
The inner cylinder 76 is limited in amount of rotation
by means of a collar 77, secured to it as by welding, abutting
the coll.ar bearing 74 and having a square projection 78 in
its rim extending rearwardly i.nto a Cllt-OUt section 79 in
the collar bearing 74. The cut-out section 79 extends
clockwise (viewed rearwardly) an amount necessary to limit the
maximum rotation of inner cylinder 76 to A5 degrees.
The inner cyllnder 76 may be locked in fixed relation to the
cylindrical arm 73 by means of tightening screw 75 on split
- 12 -
~lZ:~2~
collar bearing 74. Angle graduations 80 are provided on the
rearward edge of cut-out 79 on collar 74. The line 81 on
projection 78 serves as an angle indicator (FIG. 1 & 2).
For further description, the inner cylinder 76 will be
considered as being turned fully in the Gounter-c]ockwise
direction so that the projection 78 abu-ts on the upper encl
of the cut-out 79.
The forward end of the inner cylinder 76 is closed by a
diagonal cover plate 82 welded thereto. A fixed bearing
plate 83, having a rounded corner and a projecting ear 84,
is secured, as by welding, in a horizontally disposecl posi-
tion, to the urlderside of the forward end of inner cylinder
76. The projecting ear 84 has its forward edge perpendicular
to the longitudinal axis of arm 73 and a flange 85 welded
to its upper surface along the forward edge, at the distal
end, and projecting slightly forwardly over the edge (FIGS. 3,
4 and 6).
A rectangular companion bearing plate 86 is rotatably
attached against the underface of plate 83 by means of a
carriage bolt pivot 87 (FIG. 2) and may be locked in fixed
relation -to plate 83 by a lock knob 88 threaded on pivot
bolt 87 (FIGS. 3 and ~).
For ease of further description, plate 86 will be con-
sidered as being locked in a position such that a side edge
is parallel to the longitudinal axis of the cylindrical
arm 73 and thus the forward edge is parallel to -the lon-
gitudinal axes of the bench 11 and workpiece 13 thereon.
A saw adapter pla-te 89 is pivotably attached to, and
abuts on, the forward edge of plate 86 by means of a hori-
zontal hinge 90, having a removable hinge pivot pin 91 (FIGS.2, 3 & 7). Adapter plate 89 is thus movable, about the piv-
o-tal axis of hinge pin 91, toward and away from the workpiece
93
support surface 12. The hinge 90, being secured, as by weld-
ing, on the top surfaces of pla-tes 86 and 89, over the joint,
limits the angular movement downward of adapter plate 89
to a horizontal position where, at this point, the rear-
ward edge of plate 89 abuts the forward edge of plate 86 and
restricts further downward movement (FIG. 2).
The adapter plate 89 is designed to accommodate a con-
ventional portable circular power saw 16 mounted thereon.
A flange 92 is welded on the adapter plate 89 along the
hinge 90 (FIGS. 6 and 7) and extends the full length of the
hinge. In cross-section, flange 92 is curved upwardly and
forwardly so as to engage the turned up toe 31 of the planar
shoe 27 (FIG. 7). As best illustrated in FIG. 7, the adapter
plate 89 extends to approximately half of the length of planar
shoe 27 and has an elevated ridge 93 along the edge which
aligns along the edge 34 of the planar shoe 27, and another
elevated ridge 94, part way along the opposite edge, which
aligns along the inside edge 35 of the planar shoe saw blade
slo-t 32 thus preventing lateral and rotational movement of
the planar shoe 27 relative to adapter 89. Ridge 94 extends
from the forward edge of the adapter plate 89 rearwardly to
the extent of the saw blade slot 32, abutting against the
end 29 of slot 32 and thus preventing the planar shoe 27 from
sliding off the adapter plate 89 (FIG. 7).
An upwardly extending tilting lever 95 is welded to -the
adapter plate 89, in close proximity to hinge 90, in a pos-
ition such that its fla-t face aligns with the inside edge
of the guide notch 33 of the planar shoe 27 engaged by
adapter plate 89 (FIGS. 2 and 7). One end of a tension
spring 96 is attached to the upper end of the lever 95 and
the other end is attached to aneye 97 welded to the top
surface of arm 73 at rearward end. The -tension spring 96
- 14 -
thus acting on lever 95 biases the adapter plate 89, and the
saw 16 mounted thereon, angularly upward about the pivotal
axis of hinge 90. To limit the degree of this angular upward
tilting~ a bracket 98 is welded to lever 95, rearwardly
disposed, so that i-ts distal end abuts on the diagonal plate
82 at the end of cylinder 76, thus limiting the angular
tilting to a suitable degree determined by the length of
bracke-t 98, as best ill.ustrated in FIG. 1.
I-t is, of course, desirable that the plane of the saw
blade 20 should be parallel to the longitudinal axes of
the arm 73 and rods 58 which determine the direction that
the saw 16 traverses the bench 11 and workpiece 13. Be-
cause of the location of the til.t lever 95 with respect
to -the pivot bolt 87, which is the rotational axis of the
plate 86, the tension spring 96 has the tendency to turn
plate 86 cooperatively with adapter plate 89, and saw 16
thereon, in a counter-ciockwise direction, as viewed from
the top (FIG. 3). This rotation is limited to the posi-
tion where the plane of the saw blade 20 is parallel to
the longitudinal axis of arm 73 by a boss 99, provided on
plate 86 rearward of the end of hinge 90, which abuts on
the forward edge of plate 83 (FIG. 1 ~ 2).
The location of the pivotal bore in plate 51, is such that
the kerf of t.he saw blade 20 intersects the junction line of
bench sections 14 and 15 at the same point as the vertical
axis of pivot bolt 50, regardless of the angle at which the
arm 73 i.s set, and the saw blade 20 always passes through
the same notch in fence 15.
In lateral cutting operations the saw 16, the arm 73 and
the rods 58 are reciprocated back and forth as a unit.
Prior to a cut-ting operation, the height of the saw blade
20 with respect to the workpiece support surface 12 should
~2~5~
be adjusted, iE necessary, by loosening lock nut 72 and
moving the support colllmn 69, upwardly or downwardly in
the channel 68, to a position such that the saw blade 20
just barely contacts the surface :L2 when the saw 16 is
fully lowered with the adapter plate 89 in a horizontal
position. The lock nut 72 is then tightened, rigidly se-
curing column 69. Properly adjusted and opera-ted in this
position, the saw blade should cut a fine, shallow kerf in
the surface 12 of bench 11 and a blade notch in fence 15,
passing partly into the fence at the limlt of the rearward
movement of the saw 16.
It should be pointed out, however, that frequent depth
adjustments by means of suppor-t column 69 are unnecessary
with this cutting apparatus since the saw 16 is tiltable
upwardly and may be brought forwardly above the workpiece.
Once the correct blade depth setting has been established,
as described above, column 69 may remain locked in that
position for the duration of all subsequent cu-tting oper-
ation with that particular saw blade and make and model of
saw. If a shallow cut is desired, i.e., a cut not through
the full thickness of the workpiece, the saw blade 20 may
be raised, temporarily, on the saw 16 itself by means of
the cutting depth adjusting knob 26 (FIG. 1 and 7).
It is necessary for the lower saw blade guard 22 to be
moved upwardly, thus exposing the saw blade 20, when the
saw 16 is moved downwardly into a cut. It is also desirable,
for safety purposes, to have the guard 22 move back around
the saw blade when the saw is tilted upwardly. For this pur-
pose, a chain linkage 100, of a suitable length, is provided
between the guard operating lever 23, where it is detachably
secured by means of a hook, and the eye 97 on arm 73. When
the saw 16 is moved downwardly in an arc about hinge pin 91,
- 16 -
its distance from the eye 97 increases, and the chain
linkage 100, acting on lever 23, causes the guard 22 to
move upwardly. When the saw 16 is tilted upwardly again,
the biasing spring, incorporated in the saw assembly,
urges the guard 22 back around the saw blade 20 as the
distance to the eye 97 decreases.
To set the apparatus 10 at a desired lateral cu-tting angle
with respect to the longitudinal axis of a workpiece 13, the
lock knob 53 (FIG. 5) is loosened, the loca-ting pin 66 is
pulled upwardly against the spring bias and the arm 73 is
rotated about the pivot bolt 50 to the desired angle indi-
cated on the scale 39 by indicator 65. The lock knob 53 is
then tightened to loc~ the arm 73 in that position. If the
cutting angle is 90 degrees, or 45 degrees right or left,
the spring biased locating pin 66 will snap into apertures
provided a-t these positions in plate 51.
To execute a lateral,vertical cut on a workpiece 13, the
saw 16, with the arm 73 set at the desired cut-ting angle as
described above, is moved to the full extent rearwardly in
a tilted-up positlon, as hest illustrated in FI~. 1. This
leaves the surface 12 unobstructed and clearly visible for
placing and positioning of the workpiece 13 abutting against
the fence 15. The saw 16 is then drawn, with one hand, by
the handle 17, in the tilted-up position, forwardly over the
workpiece 13 while the other hand is used to hold the work-
piece in place. When the saw blade 20 is directly above
the forward edge of the workpiece 13, the trigger switch
18 is pulled on and the saw 16 is then plunged downwardly to
the full extent and pushed rearwardly to complete the cut,
as best illustrated in FI~S. 2 and 3. When the saw blade
20 has passed clearly through the workpiece 13, the trigger
switch 18 is released, the downward force on the handle 17
~f ~
~ ~ ~t~ 3
is eased and the tension spring 96 then returns -the saw 16
-to the tilted-up position leaving the work area unobstruc-
ted for the removal or repositioning of the workpiece.
secause of the novel design of the adapter plate 89, the
weight of the saw 16 and any downward force applied to the
handle 17, against the upwardly biasing force of the spring
96, lock the saw securely on the adapter plate 89 by the
engagement of the planar shoe 27 as previously described.
The saw 16 may be removed from the adapter plate 89 only
by tilting it forwardly, about the toe 31 of the planar
shoe 27, a sufficient amount for the end 29 of the saw blade
slot 32 to rise above the ridge 94. The toe 31 may then be
eased out from under the flange 92 and the saw lifted off.
For reasons to be pointed out further on in this descrip-
tion, it is, at times, necessary to secure the saw 16 tothe adapter plate 89 by means of screws. For this purpose,
screw holes 57, having beveled edges on the underside, are
provided in the adapter plate 89 which correspond to, and
- align with, the mounting screw holes in the planar shoe 27
and the internally threaded screw holes in the planar shoe
mounting bracket 28, as best illustrated in FIG. 7. Thus
the planar shoe 27 may be removed from the saw 16 and the
attaching screws 30 may then be used to secure tile adapter
plate 89 directly to the mounting bracket 28 on the saw 16
through the holes 57. It is also possible, if desired, to
secure the saw 16 to the adapter plate 89 with the planar
shoe 27 in place by the use of Ionger screws of the same
type as the screws 30.
To execute a bevel cut, i.e., a cut diagonal to the sur-
face 12, it is desirable to first remove the planar shoe27 from the saw 16, as described above, since it inter-
feres with the top surface of the workpiece and with the
- 18 -
3~
fence 15 when the saw is set at a bevel cutting angle.
With the saw 16 -thus secured by screws 30 direc-tly to the
adapter plate 89, the collar bearing tightening screw 75
is loosened and the inner cylinder 76, with the a~tached
saw, is ro-tated within the concen-tric cylindrical arm 73
to the desired bevel angle, as indicated on the angle gradu-
ations 80 by the indicator 81, and then the screw 75 is
tightened again. This rotation moves the pivotal axis of
the hinge 90 angularly clockwise (viewed rearwardly) from
the horizontal position and hence the plane of the saw
blade 20 is til-ted accordingly from the vextical position.
A bevel cut and a compound cut (a bevel and a miter cut)
may then be executed by the same procedure as previously
outlined for a lateral vertical cut.
I-t should be noted that the maximum bevel cutting angle
of 45 degrees is predetermined by the projection 78 abut-
ting agains-t the end of.the cutout 79, and that during a
bevel angle adjustment, as described above, the tension
spring 96 pulling on the lever 95 holds the collar 77
against collar bearing 74~
The apparatus 10 of this invention incorporates a novel
feature for the execution of rip cuts, i.e., c~ts parallel
to the longitudinal axis of an elongated workpiece. For
this type of cutting it is necessary to secure the saw 16
to -the adapter plate 89, by means of screws as previously
described, either with or without the planar shoe 27 in
place. With the arm 73 locked in the 90 degree position
and with the saw 16 moved partly forwardly to the middle
of the surface 12, the set screw 64 is tightened securing
the rods 58 and arm 73 from movement. The lock knob 88
is loosened and the adapter plate 89 and saw 16, in con-
junction with plate 86, are rotated, about pivot bolt 87,
-- 19 --
5'~3
through almost 90 degrees. The saw and adapter plate are
then eased fully downward to a horizontal position and
ro-tated further to the full extent of go degrees. In
this position the ridge 93 is aligned along the forward
edge of the projecting ear 84 and the top of the ridge 93
snaps underneath the flange 85 and is held against it in
this horizontal position by the -tension of spring 96 act-
ing on lever 95, now on the other side of pivot bolt 87,
as illustrated in ~IG. 4. Lock knob 8~ is then tigh-tened
to secure plate 86. In this position the plane of the
saw blade 20 is perpendicular to the longitudinal axis of
the arm 73 and parallel to -the fence 15 which may now
serve as a rip fence for sliding the workpiece there-
along. The saw blade 20 may now be adjusted -to the de-
sired distance from the rip fence 15 by loosening the setscrew 64 and moving the saw 16 toward or away from the
fence 15 as necessary. It may be desirable during this
adjustment to raise the saw blade 20 slightly above the
bench surface 12 to prevent snagging. This may be accom-
plished either by means of the blade depth adjusting knob26 on the saw itself or by loosening the screw 75 and rais-
ing the saw slightly thus rotating the inner cylinder 76
in the collar bearing 74. Once the desired distance from
the rip fence 15 has been located, as by a measuring tape,
the saw is locked in that location by tightening set screw
64. The saw 16 may then be lowered with the power on so
- , that the blade 20 cuts a shallow kerf in the surface 12 of
the bench 11 and then the screw 75 is tightened firmly to
secure the saw in the horizontal position. A workpiece 13
is then ripped by feeding it to the saw 16 along fence 15.
For bevel rip cuts the saw 16 may be set at a desired bevel
angle by the bevel angle adjusting knob 24 on the saw itself.
- 20 -
2~;~
Although all conventional portable clrcular power saws
have basically the same typical features, the planar shoes
of saws produced by different manufacturers may vary in
size and shape while retaining the basic typical features
of a turned up toe 31, saw blade slot 32, and guide notch
33. It is therefore necessary to have a separate, specific,
adapter plate 89 for each different make and model of saw
to be utilized by the apparatus lO. However, other than
minor changes in the dimensions and shape, such basic
features as the flange 92 and the ridges 93 and 94 are
common to all such adapter plates. Furthermore, the hinge
90, the tilting lever 95 and all the basic functions are
identical for each such plate so that any adapter plate 89
may be detached from the apparatus 10 by removing hinge
pin 91 and replaced by one that accommodates the type of
saw to be utilized.
The adapter plate 89 may, of course, be modified to act as
a saw support ~ember for accommodating a circular power saw
other than the conventional portable type herein described.
Thus, if desired, a suitable motor powered circular saw may,
with the addition of a handle, a switch, a saw blade guard,
and if necessary, a mounting bracket, be utilized by the
apparatus embodying this invention.
As has been pointed out in the foregoing description, the
aparatus lO, the preferred embodiment of this invention,
offers substantial improvements over the prior art devices.
It will be observed, however, that numerous variations and
modifications may be effected without departing from the
true spirit and scope of the novel concept of this invention.
It is to be understood that no limitation with respect to
the specific apparatus illustrated herein is intended or
should be inferred.
