Safety device for rocking arm saw

A safety device for a rocking arm saw includes a blade guard assembly which may be selectively mounted on a handle which rocks the saw blade for crosscutting operations or on a workpiece supporting surface for ripping operations. The blade guard assembly includes a guard housing substantially covering the portion of the blade which extends above the workpiece support surface and is pivotally mounted to the handle for displacing the blade by means of a first mounting arm. The blade guard is mounted on the workpiece support surface by a mounting arm having the opposite ends thereof respectively pivotally connected to the blade guard and a planar, upright support mounted on the supporting surface. The upright support is coplanar with the blade and possess a thickness no greater than that of the blade so as to pass through a cut produced by the blade when a workpiece is moved across the support surface and through the blade.

TECHNICAL FIELD 
The present invention broadly relates to safety devices for saws, 
particularly of the rocking arm type, and deals more particularly with a 
guard for protectively covering an exposed portion of the rocking 
arm-circular saw blade during both cross-cut and ripping operations. 
BACKGROUND ART 
Rocking arm circular saws are known in the art, as evidenced by U.S. Pat. 
No. 4,336,733 issued June 29, 1982, to Macksoud. The saw shown in this 
prior patent is of a bench or tabletop type construction which allows both 
cross cutting and ripping operations to be performed. The circular saw 
blade and associated driving motor therefor are both mounted on a rocking 
arm which is pivotally supported on the base of the saw, beneath a 
tabletop-like, horizontal surface which supports the workpiece to be cut. 
A generally U-shaped handle connected to the rocking arm assembly extends 
above the tabletop and provides the saw operator with a handle for rocking 
the saw blade from a lowered, retracted position beneath the tabletop to a 
raised cutting position in which at least a portion of the blade extends 
through a slot in the tabletop, above the tabletop surface. 
Crosscutting operations are performed by maintaining the workpiece 
stationary on the tabletop and rocking the saw blade from its lowered 
retracted position to its raised cutting position, thereby pulling the 
blade through the workpiece to effect the cut. In order to perform ripping 
operations, the blade is rocked upwardly to a raised position at a desired 
cutting blade height and is locked in place, following which the handle is 
removed in order to eliminate it as an obstruction above the tabletop. The 
workpiece is then pushed across the tabletop and through the exposed 
portion of the saw blade in order to effect the cut. 
Although the rocking arm saw described above is highly effective in 
operation and simple to use, the exposed portion of the saw blade above 
the tabletop presents some risk to the saw operator, even when caution is 
exercised. Heretofore, however, a safety device for guarding the saw blade 
has not been provided. 
A number of problems must be dealt with in providing a saw blade guard for 
the type of rocking arm saw described above. For example, the blade guard 
must be effective in covering the blade during both crosscutting and 
ripping operations. During the crosscutting operation, however, the blade 
moves longitudinally along the path of the cut due to its rocking motion, 
thus it is necessary to provide a guard which tracks with the blade 
throughout its longitudinal displacement. Moreover, the guard should 
preferably allow retraction of the blade, even though the guard encounters 
an obstruction during the course of its return travel. 
On the other hand, the guard must be mounted in a manner so as to cover the 
blade at all times during ripping operations but yet not present an 
obstruction to the path of travel of the workpiece and also not interfere 
when the saw is being employed in crosscutting operations. Additionally, 
for purposes of ripping operations, the guard must be positioned over the 
blade regardless of the longitudinal position of the blade which, as 
previously indicated, depends upon the blade cutting height that has been 
selected. 
Each of the foregoing design problems must be dealt with while at the same 
time, consideration must be given to the ease and portability of the saw. 
The saw described in U.S. Pat. No. 4,336,733 mentioned above is 
lightweight, compact and may be quickly converted into a readily portable 
package, consequently it is necessary that the safety device for the blade 
be compatible with the portability of the saw and the ease with which it 
may be set up and taken down. 
It is thus a primary object of the present invention to provide a safety 
device for a rocking arm saw which satisfies each of the requirements 
mentioned above. 
Another object of the invention is to provide a safety device as mentioned 
above which is relatively simple, lightweight and easy to install. 
Other objects will be made clear or will become apparent during the course 
of the following description of a preferred embodiment of the present 
invention. 
SUMMARY OF THE INVENTION 
According to the present invention, blade guard apparatus is provided for 
use with a saw of the type including a circular disc saw blade, a tabletop 
for supporting a workpiece to be sawn and including a slot therein through 
which a portion of the blade may extend above the tabletop, and means for 
mounting the blade for selective rocking movement between a retracted 
position below the tabletop and a cutting position above the table top. 
The mounting means includes a swingable handle extending above the 
tabletop for imparting rocking motion to the blade. 
The blade guard apparatus includes a blade guard which substantially covers 
or overlies the portion of the blade which extends above the tabletop, 
first means for releasably mounting the blade guard on the handle during 
crosscutting of the workpiece, and, second means for releasably mounting 
the blade guard on the tabletop during ripping operations. The first 
mounting means includes an arm, means for securing one end of the arm on 
the handle and means for pivotally connecting the other end of the arm 
with the blade guard in order to allow swinging movement of the blade 
guard relative to the handle. A releasable connection between the other 
end of the arm and the blade guard permits the guard to be disconnected 
from the handle and reconnected with the second means for mounting the 
blade guard on the table. 
The second mounting means comprises a support extending upwardly above the 
tabletop. The support includes a planar portion extending coplanar with 
the blade and has a thickness not greater than that of the blade so as to 
pass through the cut made in the workpiece as the workpiece is pushed 
through the blade during ripping operations. An elongate connecting arm 
pivotally connecting the blade guard with the upper end of the planar, 
upright support extends forwardly of the upright support and mounts the 
blade guard for pivotal movement about two axes so as to cover the blade 
at all times. An elongate slot in the connecting arm allows adjustment of 
the length of the arm to alter the position of the blade guard so as to 
cover the blade regardless of the longitudinal position of the blade. The 
second mounting means consisting of the upright, planar support and the 
connecting arm may remain on the tabletop without interfering with 
crosscutting operations, but may be easily removed to permit breakdown and 
transport of the saw.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIGS. 1 and 5 of the drawings, the present invention 
involves a safety device for use with a rocking arm saw having a base 10 
upon which there is mounted a horizontal support surface or tabletop 12 
for supporting a workpiece 13 to be sawn. The tabletop 12 includes an 
elongate slot 16 therein through which a portion of a circular disc saw 
blade 14 may extend for cutting the workpiece 13. 
The saw blade 14 along with a driving motor 20 which rotates the blade 14 
are mounted on a plate 22 which is in turn supported on a swingable rocker 
arm 18. The lower end of rocker arm 18 is pivotally mounted on the base 10 
by means of a bearing 34. A handle plate 24 secured to the rocker arm 18 
provides a means of mounting the lower extremities 28 of a saw blade 
control handle 26 on the rocker arm 18. Handle 26 is generally U-shaped 
and includes an upper portion 27 which extends upwardly through a second 
slot 19 in the tabletop 12 which is tranversely spaced from the saw blade 
slot 16 such that the handle 26 and saw blade 14 are transversely offset 
from each other. The upper portion 27 of the handle 26 extends forwardly 
and terminates in a grip 30 provided with a trigger 32 for selectively 
energizing the saw blade motor 20. The entire assembly of the saw blade 
14, motor 20, mounting plate 22, handle plate 24, rocker arm 18 and handle 
26 are swingable about a pivot point defined by the bearing 34. 
As best seen in FIG. 1, the blade 14 is swingable from a retracted, standby 
position (indicated in the phantom in FIG. 1) beneath the tabletop 12 to a 
raised cutting position in which at least a portion of the blade 14 
extends above the upper surface of the tabletop 12. As described in U.S. 
Pat. No. 4,336,733, the handle plate 24 is removably secured to the rocker 
arm 18 so as to permit removal of the handle 26 to allow rip sawing of a 
workpiece 13. Similarly, conventional means (not shown) are provided for 
selectively locking the rocker arm 18 in a fixed position with the blade 
14 at a desired cutting height during ripping operations. 
The safety device of the present invention comprises a saw blade guard 
assembly 36 (FIG. 6) for protectively covering the exposed upper portion 
of the saw blade 14 in order to reduce the risk of injury to the saw 
operator. The blade guard assembly 36 broadly comprises a blade guard 
shroud or housing 38, first means 48 for releasably mounting the housing 
38 on the handle 26 and second means broadly indicated at 50 for 
releasably mounting the guard 38 on the tabletop 12. The guard 38 may be 
mounted on the handle 26 to perform crosscutting operations or may be 
mounted on the tabletop 12 in order to perform ripping operations. As best 
seen in FIG. 6, the guard 38 includes a main pie-shaped body 39 formed of 
metal or the like. Body 39 is defined by a pair of side walls 39a having 
arcuate edges 41 connected by an end wall 39b. The lower extremities of 
the side walls 39a terminate in straight, leading and trailing edges 43 
and 45 respectively. Guard 38 further includes a pivotal segment 40 which 
is pivotally mounted on the main body 39 by means of a pivot pin 46 and 
normally covers the trailing edge 45 of the body 39. The pivotal segment 
40 possess a diameter slightly greater than that of the main body 39 and 
includes a stop 44 which is engagable with a tab 42 on the main body 39 to 
limit downward pivotal movement of section 40. A bifurcated mounting 
bracket 57 provided with a pivot pin 59 allows mounting of the guard 38 on 
the tabletop 12 using the second mounting means 50. A bearing 56 secured 
to one side wall of the main section 39 allows the guard 38 to be mounted 
on the handle 26 by the first mounting means 48. 
Attention is now particularly directed to FIGS. 5, 6 and 8 wherein the 
details of the first mounting means are depicted. The first mounting means 
48 includes an elongate, angled connecting arm 52 having a lower portion 
54 which includes an aperture 62 adapted to receive the bearing 56 
therethrough. The lower portion 54 of arm 52 has pivotally mounted thereon 
by means of a nut and screw assembly 69, a latching lever 64. Latching 
lever 64 includes a flat, arcuate edge 66 which is receivable within a 
circumferential groove 58 in the bearing 56. A finger tab 65 allows the 
latch 64 to be gripped and pivoted into and out of the groove 58. The 
arcuate edge 66 of latch 64 slidably engages the bearing 56 within the 
groove 58 to allow pivoting of the guard 38 on the lower portion 54 of arm 
52. The bottom edge of the lower portion 54 of arm 52 is provided with a 
cutout 67 therein defining a pair of stop surfaces at the opposite ends of 
the cutout 67 which are engagable by a pin 60 secured to the side wall of 
the guard 38 in order to limit the extent of pivotal movement of the guard 
38 relative to the arm 52. 
The upper end of the arm 52 angles transversely away from the guard 38 
toward the handle 26. The upper end of arm 52 is pivotally mounted to the 
handle 26 by means of a sleeve-like mounting bracket 68 secured as by 
welding to the handle 26, a screw 70 which extends transversely through 
the bracket 68 and an apertured mounting plate 72 which is secured as by 
welding to the bracket 68. Plate 72 includes a central aperture through 
which the screw 70 extends. The upper end of arm 52 includes an aperture 
through which the machine screw 70 extends and is retained on the mounting 
plate 72 by means of a nut 78. Mounting plate 72 provides a substantially 
flat mounting face for engaging and stabilizing arm 52. A pin 74 extending 
through the mounting plate 72 is received within a cutout 76 at the upper 
end of the arm 52. The surfaces at opposite ends of the cutout 76 define 
stops which are engagable with the pin 74 in order to limit the pivotal 
movement of the upper end of arm 52 relative to the handle 26. 
It may thus be appreciated that the arm 52 is pivotable about its upper end 
relative to the handle 26 within the limits defined by the stop surfaces 
of the cutout 76 to allow folding of the arm 52, and the guard 38 is 
likewise pivotable relative to the lower portion 54 of the arm 52 within 
the limits dictated by the stop surfaces defined by the cutout 67 for 
reasons discussed hereinbelow. For reasons which will also become later 
apparent, the length of the arm 52 is preferably choosen such that the 
guard 38 remains spaced above the blade 14 at all times during 
crosscutting operations, although it is recognized that a longer arm may 
be employed in order that a portion of the blade 14 is received within the 
guard 38. 
In order to mount the guard 38 on the handle 26, the latch 64 is pivoted 
into clearing relationship to the aperture 62 and the bearing 56 is 
inserted through the aperture 62. Latch 64 is then pivoted into a locking 
position with the arcuate locking edge 66 being received within the groove 
58, thus locking the guard 38 on the arm 52. At this point, the blade 
guard assembly 36 is configured to allow crosscutting of the workpiece 13. 
As shown in FIG. 5, with the handle 26 in position "A" and the blade 14 in 
its retracted position, the pivotable section 40 of the guard 38 is 
collapsed; the trailing edge 45 rests flushly on the tabletop 12 and the 
leading edge 43 of the guard 38 is elevated above the tabletop 12 a 
sufficient distance to clear the workpiece 13. As the handle 26 is pulled 
forwardly causing the blade 14 to move forwardly and up through the 
tabletop 12 into cutting relationship with the workpiece 13, the guard 38 
moves upwardly and pivots forwardly (counterclockwise as viewed in FIG. 5) 
about bearing 56 to overlie and thereby cover the leading edge of the 
blade 14, and the pivotal section 40 moves downwardly to cover the rear 
edge of the blade 14. The connecting arm 52 normally remains stationary 
relative to the handle 26 during displacement of the handle 26 by virtue 
of the pin 74 being in engagement with one extremity of the cutout 76. As 
the handle 26 is moved forwardly from position "A" to "B", the leading 
edge 43 of the guard 38 pivots forwardly and downwardly in order to 
continue covering blade 14, and the pivotal section 40 moves forwardly and 
downwardly to cover the rear portion of the blade 14. Continued 
displacement of handle 26 from position "B" to position "C" results in the 
guard 38 further pivoted forwardly, thereby assuring that the blade 14 
remains substantially covered. Return of the handle 26 from position from 
"C" to position "A" results in movement of the blade guard 38 in the 
reverse order of that described above. 
In the event that the guard 38 encounters an obstacle during the retraction 
stroke of the blade 14, the handle 26 and blade may continue to retract 
while the obstructed guard pivots about either or both the upper and lower 
end of the arm 52. 
Although the guard 38 remains spaced above the blade 14, it may be 
appreciated that the guard 38 overlies the blade 14 at all times and 
prevents objects, including the operator's hands, from falling on the 
blade 14. The spacing of the guard 38 above the blade 14 and tabletop 12 
serves the following important safety function. The edge of an elongate 
workpiece adjacent the blade 14 may swing upwardly after the sawing 
operation is completed in those cases where the other end of the workpiece 
extends outwardly beyond the tabletop 12. The vertical clearance between 
the tabletop 12 and the bottom edge of the guard 38 allows the workpiece 
edge to clear the guard as the workpiece swings upwardly, thus avoiding 
possible damage to the guard 38 and associated mounting means 48. 
As will be later described, the blade guard 38 is disconnected from the arm 
52 for ripping operations simply by releasing the latch 64 and removing 
the guard 38 from the arm 52. For storage purposes, the arm 52 may then be 
pivoted about mounting plate 72 to the storage position shown in FIG. 8. 
Attention is now particularly directed to FIGS. 1, 2, 3, 4, 6, 7 and 9, 
wherein the details of the second mounting means 50 are best depicted. The 
second mounting means 50 includes a planar, upright support 80 which 
extends upwardly above the surface of tabletop 12 and is coplanar with and 
spaced rearward from the blade 14. The upright support 80 possess a 
thickness no greater than that of the blade 14 so as to pass through a cut 
19 (FIG. 4) in the workpiece 13 produced by the blade 14. The upright 
support 80 is mounted along the rear edge of the table 12 by means of a 
base 104 secured as by welding to a U-shaped mounting bracket 106 which 
engages three contiguous edges of the tabletop 12. As shown in FIG. 9, the 
upper face of the bracket 106 includes a pair of opposing slots 108, 112 
which are of unequal length for respectively receiving therein mounting 
pins 110, 114 secured to and extending upwardly from the upper surface of 
the tabletop 12. In the normal operating position of the bracket 106, pin 
110 is positioned at the inner end of slot 108 and pin 114 is positioned 
intermediate the ends of slot 112. 
The blade guard 38 is pivotally mounted on the upper end of the upright 
support 80 by means of an elongate connecting arm 82. The forward end of 
arm 82 is provided with a slot 88 for receiving the pivot pin 59 therein. 
A latch member 84 includes a cutout 86 which cooperates with slot 88 to 
capture the pivot pin 59, thereby pivotally mounting the blade guard 38 on 
the forward end of the arm 82. The latch 84 is pivotally mounted on the 
arm 82 by means of a pivot pin 96, and a machine screw assembly 90 
extending through the arm 82 and a slot 92 in the latch 84 adjusts the 
tension required to pivot the latch member 84. A finger tab 94 provides a 
convenient means of applying pivotal pressure to latch member 84. 
The rear end of arm 82 is pivotally mounted on the upper end of support 80 
by means of a bearing assembly 100 which includes a hub 100b having an 
outer face formed preferably of rubber 100a. The hub 100b includes a 
threaded shaft 100d which extends through an aperture in the support 80. A 
circular retainer plate 100c is secured to the hub 100b so as to retain 
and freely pivotally mount the hub 100 on the support 80. The arm 82 
includes longitudinally extending, elongate slot 98 therein. The threaded 
shaft 100d extends transversely through the slot 98 such that the arm 82 
is captured between the retainer plate 100c and a threaded locking knob 
102 received on the shaft 100d. Tightening of locking knob 102 draws the 
arm 82 tightly against the retaining plate 100c thus preventing 
longitudinal movement of the arm 82 relative to the support 80. However, 
arm 82 remains freely pivotable about the upper end of the support 80 by 
virtue of the free pivotal mounting of the hub 100 on the upright support 
80. 
In order to perform ripping operations, the blade guard 38 is positioned 
beneath the arm 82 and the pivot pin 59 is inserted through the aligned 
opening presented by the cutout 86 and the slot 88. The latch 84 is then 
pivoted from an open position to a locking position thereby pivotally 
mounting the guard 38 on the forward end of the arm 82. The rocking arm 18 
having been locked in position such that the blade 14 is at a desired 
cutting height, it is then necessary to longitudinally position the blade 
guard 38 above the blade 14. This is accomplished by loosening the locking 
knob 102 and sliding the assembly of the arm 82 and guard 38 until the 
guard 38 is substantially positioned above the fixed position of the blade 
14. The locking knob 102 is then tightened to fix the longitudinal 
position of the blade guard 38. 
As best seen in FIG. 1, the workpiece 13 is guided toward the blade 14 with 
the aid of a conventional ripping fence 17. The trailing edge 45 of the 
blade guard 38 rests on the tabletop 12, with the leading edge 43 thereof 
slightly elevated to received the workpiece 13 therebeneath. As the 
forward edge of the workpiece 13 engages the leading edge 43 of the guard 
38, the blade guard 38 and the arm 82 move upwardly, causing the guard 38 
to pivot relative to the arm 82 while the rear end of the arm 82 likewise 
pivots about the upper end of the support 80. Forward pivoting of the 
guard 38 causes the leading edge 43 of the guard 38 to cover the leading 
edge of the blade 14. The guard 38 continues to pivot counterclockwise as 
shown in FIG. 1 until the leading edge 43 flushly engages the workpiece 
13, as shown in FIG. 3; at this point, the pivotal section 40 of the guard 
38 has moved downwardly to cover the rear edge of the blade 14. As 
previously mentioned, the thickness of the support 80 is no greater than 
that of the blade 14, consequently the support 80 passes through the cut 
19 in the workpiece 13, thus permitting passage of the workpiece. After 
the workpiece 13 clears the blade 14, gravity draws the guard 38 and arm 
82 downwardly, so as to continue protectively covering the blade 14. 
When it is desired to change over from ripping to crosscutting, the blade 
guard 38 is released from arm 82 by unlatching the pivot pin 59 and the 
guard 38 is then reattached to arm 52 associated with the handle 26 as 
previously described. Locking knob 102 is then loosened and the arm 82 is 
slid to its rearmost position and is locked in place with locking knob 
102. It is to be understood, however, that it is not necessary to remove 
the upright support 80 from the tabletop 12 since, with the arm 82 fully 
retracted, neither the arm 82 nor the upright support 80 present any 
obstruction which would impede cross-cut operations. 
From the foregoing, it may be appreciated that the blade guard 38 may be 
easily and rapidly connected to either the handle 26 for crosscutting or 
to the upright support 80 for ripping using a minimum of mounting 
structure. The blade guard assembly 36 is also well suited for portable 
rocking arm saws, such as that disclosed in U.S. Pat. No. 4,336,733, the 
components of which readily breakdown for storage and transport. For 
example, in order to breakdown the saw for storage or transport, the blade 
guard 38 is removed from either the mounting means 48, 50. The mounting 
arm 52 is then swung to a folded, storage position, and the entire second 
mounting means 50 is removed from the tabletop 12 by sliding the bracket 
106 transversely toward the right as viewed in FIG. 9, until clearance 
with pin 110 is acheived following which the bracket 106 may be removed by 
pivoting the bracket 106 in the direction of arrow 113 about pin 114 and 
withdrawing it from the edge of the tabletop 12. 
In view of the above, it is apparent that the safety device for the rocking 
arm saw described above not only provides for the reliable accomplishment 
of the objects of the invention, but does so in a particularly safe, 
effective and economical manner. It is recognized, of course, that those 
skilled in the art may make various modifications or additions to the 
preferred embodiment chosen to illustrate the invention without departing 
from the spirit and scope of the present contribution to the art. 
Accordingly, it is to be understood that the protection sought and to be 
afforded hereby should be deemed to extend to the subject manner claimed 
and all equivalents thereof fairly within the scope of the invention.