Motorized miter chop saw with work-piece clamp

A motor operated circular miter chop saw is pivotally mounted on a generally horizontal axle pivot bolt about which it rotates in a vertical plane with the axle pivot bolt being carried by a cast support base structure. Angular orientation of the work-piece is provided by an angularly adjustable fence rotatably carried by the cast base support structure. Clamping means are also provided selectively mountable with the cast support base to provide hold-in clamping action for holding a work-piece against the fence or mountable with the fence to provide hold-down clamping action for holding a work-piece against the cast support base.

DESCRIPTION 
1. Field of the Invention 
This invention relates to powered miter circular chop saws and a novel 
workpiece clamp selectively mountable on the fence thereof or mountable on 
the table thereof and finding particular utility with such a saw having a 
rotatably positionable fence for cutting elongated stock material such as 
wood to length at various reproducable angles while enabling the cutting 
plane of the saw to remain fixed. 
2. BACKGROUND OF THE INVENTION 
In various crafts projects it is useful to be able to accurately cut 
elongated stock material, such as strips of wood, or the like, to length 
and at accurately reproducable angles. For example, in many construction 
projects it is desired to cut strips of wood so that the end cut is 
square, that is, perpendicular to the longitudinal axis of the wood strip. 
At other times it is desirable to cut at angles other than 90.degree. such 
as at a 45.degree. angle to enable two such strips to be mitered to 
provide a square or right angle half miter corner joint. Motorized miter 
saws in which a power driven circular saw is pivotally supported on a 
support member for vertical swinging movement downwardly from a normal 
inoperative rest position towards a work support base structure while also 
pivotally supporting the saw support member on a vertical axis for angular 
swinging movememt to preselected angular positions to effect a desired 
angle cutting of the work-piece have been previously shown and saws of 
this type are disclosed, for example, in Niehaus et al U.S. Pat. No. 
3,821,918 and are commonly referred to as chop saws. A disadvantage of 
such saws is the necessity for pivoting the saw assembly for angular 
setting and the weight and vibration of the saw necessitates that the saw 
support member be rather heavy and closely machined to provide for long 
life and continued accuracy. Among other disadvantages, this necessity 
makes such construction more expensive than might be otherwise desirable. 
Moreover, since the saw blade must descend to a position beneath the work 
supporting surface in order to completely sever the work-piece, means must 
be provided to enable the saw to pass through the work supporting surface 
at a number of angular positions which further increases the complexity 
and, accordingly, the cost of such saws. In some saws this is achieved by 
providing a rotating platform which rotates with the saw, further adding 
to the complexity and expense of the machine. If such means are not 
provided, then a disposable work supporting surface, such as a piece of 
scrap wood, must be used beneath the work-piece or a movable fence, or the 
like may be provided to enable relative lateral movement of the work piece 
and the saw path, therefore necessitating both the chopping movement of 
the saw and lateral movement of the work-piece or saw which results in a 
loss of convenience and a possible lessening of accuracy as well as an 
increase in complexity and expense. In the present saw the difficulties 
are reduced by providing a pivotal fence for positioning the work-piece 
and a fixed chordal clearance in the saw base for the saw blade together 
with means for mounting the fence in position while guiding it for pivotal 
movement of the saw base enabling a simple chop action of the saw to sever 
the work-piece at any desired angle while the saw blade always enters the 
chordal clearance slot. 
While such construction has certain advantages over saws having a laterally 
swingable cutting plane, such saws may, in certain circumstances, prove 
slightly more awkward and inconvenient to the operator. For example, when 
long and heavy work-pieces are to be cut at an angle, the necessity to 
also position the work piece itself at an angle may make the weight of the 
work piece difficult to balance or support. I have found it desirable, 
therefore, to provide such saws with an adjustable work-piece clamp 
selectively usable as a hold-down or as a hold-in. 
OBJECTS OF THE INVENTION 
Accordingly, it is a primary object of the present invention to provide 
novel and improved miter saws designed, constructed and arranged to 
maximize economy of production while simultaneously maintaining good 
operating convenience, safety and accuracy. 
Another primary object of the present invention, in addition to the 
foregoing object, is the provision of novel and improved miter saws 
utilizing a cast base structure to which a motor powered circular chop saw 
is pivotally mounted for rotation about a horizontal axis and a work-piece 
fence is pivotally mounted for rotation about a vertical axis intersecting 
the saw axis, together with a work-piece clamp selectively and adjustably 
carried on the fence. 
Yet another primary object of the present invention, in addition to each of 
the foregoing objects, is the provision of such a miter saw wherein novel 
and improved mounting means are utilized for selectively mounting the 
clamp to the fence or to the base support structure so as to enable 
accurate orientation of the work-piece relative to base support structure 
and support of the work-piece conveniently even while the fence is rotated 
or positioned at any desired angular orientation. 
Still another primary object of the present invention, in addition to each 
of the foregoing objects, is the provision of novel and improved motor 
powered circular miter chop saw of the class described with an angularly 
adjustable and lockable fence against which a work-piece may be positioned 
to define the angle of cut thereof, together with a quickly adjustable 
work-piece clamp selectively carried on either the fence to be effective 
as a work piece hold down to clamp the work-piece against the saw table or 
on the table as a work-piece hold-in to clamp the work-piece against the 
fence. 
Yet another and still further primary object of the present invention, in 
addition to each of the foregoing objects, is the provision in a motor 
driven circular miter chop saw of the class defined wherein the work-piece 
clamp is effective and convenient for clamping work-pieces of diverse 
sizes and shapes, including square, rectangular, circular and complex 
cross-sectional configurations. 
The invention resides in the combination, construction, arrangement and 
disposition of various component paths and elements incorporated in 
improved motor driven circular miter chop saws and work-piece clamping 
means therefore constructed in accordance with the principles of this 
invention. The present invention will be better understood and objects and 
important features other than those specifically enumerated above will 
become apparent when consideration is given to the following details and 
description which, when taken in conjunction with the annexed drawing 
describes, discloses, illustrates and shows a preferred embodiment or 
modification of the present invention and what is presently considered and 
believed to be the best mode of practicing the principles thereof. Other 
embodiments or modifications may be suggested to those having the benefit 
of the teachings herein, and such other embodiment or modifications are 
intended to be reserved, especially as they fall within the scope and 
spirit of the subjoined claims. 
SUMMARY OF THE INVENTION 
In accordance with the present invention a motor operated circular miter 
chop saw is pivotally mounted on a generally horizontal axle pin or bolt 
about which it rotates in a vertical plane with the axle bolt being 
carried by a cast support base structure. Angular orientation of the work 
piece is provided by an angularly movable fence rotatably carried by the 
cast base support structure. Detent means are provided for locating the 
rotatable fence structure for work-piece cut-off at a right angle or 
90.degree. (sometimes referred to as 0.degree. of miter) as well as at 
45.degree. right and left orientation. Lock means are also provided for 
firmly locking the fence in a desired orientation, whether in the detent 
positions or any position therebetween. A work-piece clamp is also 
provided which is quickly and easily adjustable and selectively carried on 
the fence or the table to function as a work-piece hold-down or work-piece 
hold-in, respectively. 
While the saw described is primarily intended for the cutting of soft 
material such as wood, utilizing a wood cutting blade, it is intended that 
this application also cover similar devices provided with metal cutting 
blades, abrasive discs, and the like, for cutting and facing diverse 
materials.

DETAILED DESCRIPTION OF THE INVENTION 
With reference now to the drawing, wherein like reference characters are 
utilized for like parts throughout the various views, there is shown and 
illustrated a motor operated circular miter chop saw constructed in 
accordance with the principles of the present invention and designated 
generally by the reference character 10. The miter saw 10 comprises a cast 
base structure designated generally by the reference character 12, a motor 
driven circular saw structure designated generally by the reference 
character 14 rotatably carried on a pivot assembly generally designated by 
the reference character 16 mounted with the cast base structure 12 and a 
rotatable fence structure designated generally by the reference character 
18 rotatably carried by the cast base structure 12 for limited rotational 
movement about a vertical pivot located on or adjacent the plane of the 
circular saw blade 20 of the motor driven circular saw 14. In addition, 
biasing means (not shown) and more particularly described in detail in my 
copending application Ser. No. 61,163 filed July 26, 1979, executed by me 
July 9, 1979, and incorporated herein in its entirety by reference, may be 
provided for biasing the circular saw 14 in an upward direction towards an 
open position whereat the circular saw 14 is generally spaced above the 
cast base portion structure 12 for the insertion of an elongated 
work-piece 24 therebetween to rest on a work supporting surface 26 defined 
by the top surface of the cast base portion 12 and against the work 
supporting face 28 on the fence structure 18 generally perpendicular the 
work supporting surface 26. A generally arcuate depression or clearance 
slot 30 is provided in the cast base structure 12 in general alignment 
with the circular saw blade 20 to enable the circular saw blade 20 to pass 
through the plane of the work supporting surface 26 as the saw is lowered 
against the force of the biasing means to cut the work-piece. The fence 
structure 18 is also provided with a generally central slot 32 to provide 
clearance for the saw blade 20 for the same purpose, the slot being wide 
enough to accommodate the saw blade 20 even at the extremes of the fence 
rotation. Stop means (not shown) such as that also more fully described in 
my aforesaid copending application may also be provided for limiting the 
downward pivoting chop motion of the motorized circular saw 14 to prevent 
the circular saw blade 20 from contacting the bottom of the saw clearance 
groove 30 or the fence structure 18 rearward of the saw clearance slot 30. 
Detent means (not shown) may also be provided to quickly and easily locate 
the fence structure 18 rotatably in any of several preferred positions 
such as, for example, perpendicular the plane of the saw blade 20 and at 
45.degree. angles right and left thereof, and locking means designated 
generally by the reference character 34 are also provided for positively 
locking the fence structure 18 in a desired angular orientation. 
In addition to the upper work supporting surface 26, the cast base 
structure 12 further comprises a pair of side walls 38, a curved front 
wall 40 and a rear wall 42, each depending therefrom with laterally 
outwardly extending feet 44 being integral with the lower edges of the 
walls 38, 40 and 42 at the four corners for supporting the miter chop saw 
10 on a table, or the like. Mounting apertures 46 are provided in each 
foot 44 to enable the miter chop saw 10 to be fastened rigidly in 
position. Projecting generally rearwardly of the rear wall 42 of the cast 
base structure 12 and forming an integral part thereof, there is provided 
a generally U-shaped channel portion 48 extending upwardly above the plane 
of the work supporting surface 26 to define a pair of mounting ears 
forming a part of the circular saw mounting means 16. 
As heretofore pointed out, the circular saw structure 14 is pivotally 
mounted, and the support means 16 therefore comprises a pin or pivot bolt 
50 extending through the side wall 48 and adjustably mounted therein as is 
described in more detail in my aforesaid copending application 
incorporated herein by reference. The bolt 50, as set forth therein 
extends through a boss 52 integrally formed with a blade guard and motor 
supporting casting 54 forming the main supporting structure of the 
circular saw structure 14. The blade guard casting 54 has an electric 
motor (not shown) mounted to one side thereof for driving the circular saw 
blade 20 and crries a handle portion 56 for enabling the circular saw 
assembly 14 to be controlled, i.e., lowered for cutting action and raised. 
As heretofore pointed out, the motorized miter chop saw of the present 
invention utilizes a rotatably mounted fence 18 with a work-piece 24 being 
positioned against the front face 28 of the fence 18 and supported on the 
work supporting surface 26. Especially in the case of a very long work 
piece, imbalance of the work piece may make it difficult to support the 
work piece as desired for safe and accurate cutting. Accordingly, and in 
accordance with the present invention, the miter saw 10 is further 
provided with a work clamp, designated generally by the reference 
character 58 which may be quickly and easily associated with and adjusted 
relative to either the fence 18 or the work supporting surface 26 so as to 
clamp the work-piece 24 into the table 26 or the front face 28 of the 
fence 18. Accordingly, and with particular now to FIG. 1, the clamp 58 is 
shown and illustrated associated with the fence 18 so as to operate as a 
hold-downn clamp, clamping the work-piece 24 against the work supporting 
surface 26. 
The work clamp 58, in accordance with the present invention comprises an 
elongated tubular clamp sleeve 60 having a longitudinal bore 62 
therewithin and a clamping spindle 64 extending through the hollow bore 
62. The upper end of the elongated clamp sleeve or tube 60 is of a reduced 
internal diameter and internally threaded, as indicated by the reference 
character 66 while the upper end portion of the spindle 64 is likewise 
screw threaded, as indicated by the reference character 68 for jack screw 
cooperation therewith. The upper end portion of the spindle 64 is provided 
with a knurled thumb piece 70. 
The lower end portion of the spindle 64 has a reduced diameter portion 72, 
terminating in a shoulder 74. A generally cup-shaped clamping member or 
pad 76 having a generally central aperture 78 is fit over the reduced 
diameter portion 72 and rotatably held in position thereon against the 
shoulder 74, as by means of a split washer 80. The lower end portion of 
the cup-shaped clamp member 76 is generally hollow and open, as shown, 
having a generally annular flat rim 81 provided with a V-shaped notch 82. 
Hence, the cup-shaped clamp member may be securely engaged against a flat 
work piece, as shown, or the notch 82 thereof may be utilized to engage a 
curved surface work piece without slippage. As will be readily apparent, 
rotational movement of the knurled thumb piece 70 is effective to advance 
and retract the spindle 64 and associated clamp member 76 relative the 
hollow clamp sleeve or tube 60. 
The clamp sleeve or tube 60, which is preferably of generally circular 
cylindrical configuration, is received in a bore 84 provided with an 
adjustment or clamp block 86 and a first cross bore 88 communicates with 
the bore 84, the first cross bore 88 being internally screw threaded, as 
shown, for receipt of a knurled threaded thumb screw 90. Accordingly, if 
the knurled threaded thumb screw 90 is unscrewed slightly, the sleeve 60 
may be rapidly moved within the bore 84 to quickly position the clamp 
member 76 against a work piece 24 or remove the clamp member 76 from 
engagement therewith. Once positioned in engagement against the work piece 
24, the clamp member 76 may be quickly tightened thereagainst by means of 
a slight rotation of the knurled thumb piece 70. 
The clamp block 86 is further provided with a second bore 92 which also 
extends generally perpendicular the spindle bore 84 and a support bar or 
stub shaft 94 preferably of generally circular cylindrical configuration 
is inserted within the bore 92 and clamped in position therewithin, as by 
means of a set screw 96. The bar 94, in turn, is carried within a bore 98 
of a clamp mounting block 100 so as to be slidable and rotatable 
therewithin for quick and rapid positioning of the clamp 58. To lock the 
support bar or stub shaft 94 in a desired position within the bore 98, the 
clamp mounting block 100 is further provided with a first threaded cross 
bore 102 and a locking knurled threaded thumb screw 104 similar to the 
thumb screw 90 carried in the first threaded cross bore 102. 
The clamp mount block 100 is in turn structurally associated with the fence 
18, as by means of a generally vertical fixed support shaft 106, which may 
be of generally circular cylindrical configuration having its upper end 
portion mounted within a bore 108 in the clamp mount block 100 and locked 
in position therein, as by means of a set screw 110. The lower end portion 
of the shaft 106 is mounted within a bore 112 provided on the fence 18 and 
held in position therewithin, as by means of a set screw 114. 
As heretofore pointed out, the work-piece clamp 58 has utility not only as 
a hold-down while mounted on the fence 18 but is also adapted to be 
structurally associated with the table 12 and selectively positioned 
relative thereto so as to be effective to operate as an adjustable 
work-piece hold-in, for clamping a work piece 24 against the face 28 of 
the fence 18, regardless of the angular orientation of the fence 18 on the 
table or cast support structure 12. 
Accordingly, and with reference more particularly to FIGS. 2 through 4, the 
table or cast support structure 12 is specifically constructed and 
arranged so as to enable the clamp 58, and particularly the clamp block 
86, stud shaft 94, spindle tube or sleeve 60 and spindle 64 to be 
selectively mounted and oriented relative thereto. Accordingly, the table 
or cast base structure 12, generally adjacent the curved forward wall 40, 
is provided with one or more generally vertically extending bores 116 (see 
FIG. 3) into which the stud shaft 94 may be inserted, and locked in 
position, as by means of a knurled threaded thumb screw 118 engaged within 
a threaded bore 120 provided in the front wall 40 generally adjacent the 
work supporting surface 26 and in axial alignment with the bore 116. As 
seen, positioning the stud shaft 94 in a vertical direction, as indicated 
in FIGS. 2-4, positions the clamp tube or sleeve 60 generally horizontal 
and parallel the work surface 26 so that it may be angularly oriented so 
as to be perpendicular the fence front surface 28 of the fence 18 or, for 
tapered pieces, or the like, at any desired angle relative thereto whether 
the fence is positioned for right angle cut off, as shown and illustrated 
in FIG. 2, for 45.degree. miter cut off as shown and illustrated in FIG. 
4, or at any angle intermediate thereto. The knurled threaded thumb screws 
90 and 118 enable the clamp 58 to be quickly positioned as desired, after 
which it may be quickly tightened, by turning the thumb piece 70. 
It is to be understood that the invention is by no means limited to the 
forms of embodiment described and illustrated, which have been given by 
way of example only. In particulate, it comprises all the means 
constituting technical equivalents to the means described as well as their 
combinations, should the latter be carried out according to the spirit of 
the invention.