DESCRIPTION
Technical field
[0001] The present invention relates to a cutter for an endless cutter device movable along
a path for cutting a kerf in a work piece, said cutter in an upright position comprising:
a body portion disposed in a substantially upright plane and having forward and rearward
regions,
a cutter portion on the rearward region of the body portion having a forwardly facing
cutting edge at a selected elevation above the body portion, and
a depth gauge portion on the forward region of the body portion, said depth gauge
portion comprising a plate portion bent over at a substantial angle relative to the
plane of the body portion and inclined downwardly from a rearwardly facing rear edge
having an elevation adjacent but below the elevation of the cutting edge to a forwardly
facing front edge at a lower elevation, and in particular it relates to an improved
depth gauge.
Background and Summary of the Invention
[0002] A cutter of the above preamble is known from US-A-4,911,050, which discloses a bent-over
depth gauge, whereby there is a face of the depth gauge sliding of a kerf produced.
The present invention relates to an improved cutter, and more particularly to a cutter
which has an improved depth gauge.
[0003] Cutters for endless cutter devices movable along a path for cutting a kerf in a work
piece, such as may be found in a saw chain for cutting wood, generally have a cutter
portion with a leading cutting edge and a depth gauge portion spaced forwardly of
the cutting edge to control the depth of cut taken by the cutter. The depth gauge
is instrumental in reducing the possibility of kickback during operation of the saw
on which the chain runs.
[0004] Depth gauges in the past generally have included a single thickness of cutter material
which extends upwardly in a region spaced forwardly from the cutter edge as disclosed
in Silvon U.S. Patent No. 4,353,277. others have included bent-over depth gauge portions
such as disclosed in U.S. Patents Nos. 5,085,113 and 4,989,489 to Pinney, U.S. Patent
No. 4,911,050 to Nitschmann and U.S. Patent No. 4,841,825 to Martin.
[0005] The single thickness upright depth gauge as illustrated in 4,353,277 may have a tendency
to dig into the work piece and not provide consistent cutting depth control. Further
it is less stable than a bent-over depth gauge. The bent-over depth gauges illustrated
in 4,911,050; 4,989,489; and 5,085,113 generally have substantially rectangular configurations
as viewed in plan. The depth gauge of 4,841,825 wraps over the majority of the chain
width and substantially encloses the space leading the cutter edge. Although these
prior devices produce depth of cut control, they can produce excessive friction and
drag and also inhibit the free flow of chips produced by the cutters. Explaining further
if chips produced by the cutter are not allowed to flow easily under the top plate
of the cutter they will continue to build up in the kerf, and the depth gauge and
cutter will tend to ride thereover producing inefficient cutting.
[0006] An object of the present invention is to provide a cutter having a novel depth gauge
leading a cutter edge which overcomes the disadvantages of prior devices.
[0007] More specifically, an object of the present invention is to provide a cutter having
a bent-over depth gauge leading a cutting edge, which depth gauge has a rear edge
with a central portion nearest the cutting edge of the cutter and at least one side
portion which extends forwardly and downwardly from the central portion at an angle
relative to the center line of the cutter. This provides good stability, depth of
cut control, and kickback control while permitting free flow of chips to clear the
kerf cut in the work piece.
[0008] Another object is to provide such a novel cutter with a bent-over depth gauge in
which the rear edge has a central portion nearest the cutting edge and side portions
which extend forwardly and downwardly from the central portion, diverging from each
other as they progress forwardly.
[0009] More specifically an object of the present invention is to provide such a novel cutter
having a depth gauge with a narrow central portion at its rear edge which is at the
greatest elevation for the depth gauge, with remainder portions of the depth gauge
sloping downwardly therefrom on progressing forwardly in the cutter.
[0010] Still another object of the present invention is to provide a cutter with a novel
bent-over depth gauge which has a minimum width at its greatest elevation, and on
progressing forwardly and downwardly from such minimum width portion has a central
region of maximum depth gauge width intermediate its rear and front edges, thus to
provide good depth gauge control, cutter stability, free chip flow, and reduction
of friction and drag on the cutter as it moves through the kerf in the work piece.
[0011] Yet another object is to provide a novel cutter for use in an articulated cutter
chain having a clipped heel on the underside of the cutter and a bent-over depth gauge
which will cooperate to assist in stabilizing the chain and minimize vibration during
use of the chain.
[0012] In prior cutting devices, as with the present device, as the cutting portion is sharpened,
such usually occurs from the front of the cutter which increases the size of the gullet
space between the cutter edge and the depth gauge. In past cutters, it has been found
that increasing the distance between the depth gauge and the cutting edge often has
increased kickback potential of the cutters. It has been found that the present invention
and configuration of the depth gauge therefor maintains a greater degree of kickback
control as sharpening occurs, thus resisting the tendency of prior devices to increase
kickback through cutter life.
[0013] Yet another object of the present invention is to provide a cutter having such a
novel depth gauge which has a maximum width that is at least as great or greater than
the width of the cutter top plate and cutting edge to lend additional stability to
the cutter during operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
Fig. 1 is a side elevation view of a section of a saw chain incorporating cutters
according to an embodiment of the invention;
Fig. 2 is an enlarged side elevation view of a cutter link removed from the chain
of Fig. 1;
Fig. 3 is a top plan view of the cutter of Fig.2;
Fig. 4 is an enlarged front elevation view of the cutter taken along the line 4-4
in Fig. 1 as it would be attached to other links in the chain;
Fig. 5 is an enlarged side elevation view of a second embodiment of a cutter link
removed from a chain as shown in Fig. 1;
Fig. 6 is a top plan view of the cutter of Fig. 5; and
Fig. 7 is an enlarged front elevation view of the cutter of Fig. 5 taken along a line
similar to the line 4-4 shown in Fig. 1 illustrating the cutter as it would be attached
to other links in the chain.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0015] Referring to the drawings, and first more particularly to Fig. 1, at 10 is indicated
generally a section of a cutter chain for use with a chain saw. The chain includes
left and right hand cutter links 12, 14, center drive links 16 and connector links
18, 20. All of these links have bores extending therethrough adjacent opposite ends.
Rivets 22, acting as pivot pins, extend through aligned bores in the links to pivotally
interconnect the cutter, drive, and connector links together.
[0016] The chain is supported for travel on a guide bar, a portion of which is indicated
at 26 having a groove 28 in which depending tang portions of drive links 16 slidably
move. The undersides of the cutter links and connector links ride slidably along supporting
guide rails 26a, 26b at opposite sides of groove 28.
[0017] Referring to Figs. 2, 3 and 4, a left-hand cutter link 12 is illustrated in enlarged
form to illustrate an embodiment of the present invention. The cutter, or cutter link,
12 includes a substantially planar upright body portion 32 having a center plane noted
generally at 33. A pair of spaced apart rivet receiving bores 34, 36 extend through
the rear, or heel, region 32a and the front, or toe, region 32b, respectively, of
body 32. The centers of bores 34, 36 are aligned on a center line 39 which is generally
parallel to the guide rails 26a, 26b on which the chain runs.
[0018] As is best seen in Fig. 2 the underside 41 of the cutter body under bore 36 in the
toe region adjacent the front of the cutter is spaced a selected distance 41a beneath
the center of bore 36. The underside 43 of the cutter body under the center of bore
34 is clipped so that it angles upwardly on progressing to the rear at an angle of
1-1/20 to 50 relative to centerline 39. The distance 43a to the underside of portion
43 from the center of bore 34 is less than distance 41a, preferably in a range of
0.01 to 0.08inch. This distance will vary in relation to the size and style of cutter.
[0019] The rear end region 32a of the body has a cutter portion 40 thereon. The cutter portion
includes a cutter top plate portion 42 and a forwardly facing cutting edge 44. The
cutter top plate portion is bent over at substantially a right angle relative to and
overlies body portion 32 of the cutter. The cutting edge 44 extends transversely of
the plane of the body portion and overlies the body portion.
[0020] The cutting edge 44 is spaced a selected elevation above the body portion for cutting
purposes. The free outer end of the cutting edge 44 is spaced a distance 45 from the
center plane 33 of the body portion.
[0021] A depth gauge portion 46 is mounted on the front end region 32b of the body portion.
The depth gauge portion includes a plate portion 48 which is bent over at a substantial
angle relative to the plane of the body portion and has a substantially planar upper
surface 48a which is inclined continuously downwardly on progressing forwardly in
the cutter. The depth gauge portion in the illustrated cutter is bent over at substantially
a right angle relative to the plane of the body portion and overlies the body portion.
As is best seen in Fig. 4 a juncture section 52 disposed at a slight angle relative
to the plane of body portion 32 interconnects the body portion and depth gauge portion
and the depth gauge is cantilevered outwardly therefrom with a free outer edge.
[0022] Referring to Fig. 3, it will be seen that the depth gauge plate portion 48 is multi-angular,
and in this embodiment is substantially pentagonal. The rearwardly facing rear edge
of he plate portion 48 has a central portion 56 nearest cutting edge 44. The rear
edge has opposed side portions 58, 60 which in the illustrated embodiment extend forwardly
from central portion 56 and diverge from each other on progressing forwardly from
the central portion. As is seen in Fig. 3, the central portion 56 is formed by the
juncture of side portions 58, 60, is substantially a convex curve, and has a width
which is a minor portion of the overall width of the depth gauge. The side portion
58 could extend perpendicular to center plane 33 from central portion 56, if desired,
with side portion 60 alone extending forwardly and downwardly from the central portion.
However, it is believed that operational benefits occur by having both sides 58, 60
angled forwardly from the central portion.
[0023] Referring to Figs. 3 and 4, cutting edge 44 has a defined width 47 extending laterally,
or transversely, of the cutter, and central portion 56 of the rear edge of the depth
gauge is disposed intermediate, and here substantially centrally of, opposite ends
of the cutting edge.
[0024] As side portions 58, 60 extend forwardly from central portion 56, not only do they
diverge from each other but they also slope downwardly from central portion 56. Thus,
central portion 56 is disposed at the greatest elevation relative to the body portion
and nearest the elevation of cutter edge 44. The central portion 56 of the rear edge
of the depth gauge is aligned forwardly of an intermediate region of the cutting edge
44.
[0025] Extending forwardly from rear edge side portions 58, 60 are opposed side edges 64,
66. These side edges converge toward each other as they progress forwardly from their
junctures with side portions 58, 60. They join with opposite ends of front edge 68
which extends substantially laterally of the plane of the body portion.
[0026] The juncture between rear edge side portion 60 and side edge 66 is formed in a convexly
curved outer edge 70 which is at the region of maximum width for the depth gauge.
Since the depth gauge plate portion 48 is joined only along side edge 64 to juncture
portion 52, it has a free side region extending away from the body portion which includes
rear edge side portion 60 and side edge 66 which converge in the convex curve at central
region 70. As is best seen in Figs. 3 and 4, the maximum width portion 70 of the depth
gauge is disposed at an elevation intermediate the highest and lowest portions of
the depth gauge, between the front and rear edges of the depth gauge. As seen in Figs.
3 and 4 in the embodiment illustrated the maximum width 71 of the depth gauge portion
is at least as great or greater than the width 47 of the cutter portion 40 following
it. Further, the outer edge 70 of the depth gauge projects a distance 73 laterally
of central plane 33 which is greater than the distance 45 for cutter edge 44.
[0027] Referring to Fig. 4, a right-hand cutter 14 is illustrated which follows cutter 12
in the chain as shown in Fig. 1. A major portion of the top plate of the cutter 14
and its depth gauge are broken away so that they do not interfere with illustration
of the major portions of cutter 12. However, it will be seen that central region 70
of depth gauge 46 in the embodiment of cutter 12 illustrated extends outwardly beyond
the width of top plate 44 toward the side of the kerf which would be cut by the side
cutting edge of cutter 14. Such extension of the depth gauge toward the opposite side
of the chain has been found to improve chain stability during cutting.
[0028] In Fig. 2 distance 74 denotes the elevational distance that the uppermost portion
of depth gauge 46 is spaced below the uppermost edge of cutting edge 44. This is known
generally as the depth gauge setting for the cutter.
[0029] Referring still to Fig. 2, depth gauge 46 is spaced a distance forwardly of cutter
portion 40 to provide an open gullet space 78 therebetween.
[0030] Various angular relationships between the sides, or edges, of the depth gauge are
illustrated in Fig. 3. A line 82 is drawn extending normal to the central plane of
the cutter body. Angles 84 and 86 denote the orientations of rear edge side portions
58, 60, respectively, relative to line 82. An included angle 88 is defined between
rear edge side portions 58, 60. Another line 90 is drawn extending normal to the central
plane of the cutter adjacent the forward end of the depth gauge. Angles 94, 96 denote
the orientations of side edge 66 and front edge 68, relative to line 90.
[0031] An exemplary cutter will now be described having a pitch distance between the center
of bores 34, 36 of approximately 0.390 inch, and an overall height of approximately
0.520 inch, depth gauge setting distance 74 may be in a range of 0.015 to 0.030 inch.
The following sizes, angles and distances are measured along a horizontal plane, indicated
generally at 91 in Fig. 2, and as viewed in plan in Fig. 3. Depth gauge portion 46
may have an overall length of approximately 0.175-0.30 inch. Outer edge 70 of the
depth gauge would be in a range of 0.050 to 0.150 inch forwardly of rear edge central
portion 56. Angle 84 may be in a range of 00 to 300 (preferably 100 to 300), angle
86 in a range of 100 to 400, and included angle 88 in a range of 1100-1700, and preferably
1100 to 1600. Angle 94 is in a range of 100-550 and angle 96 in a range of 00 to 150.
The downward slope 98 of the upper planar surface 48a as shown in Fig. 2 is in a range
of 250 to 350.
[0032] Referring to Fig. 4, a dashed line 100 illustrates generally the outline of substantially
rectangular depth gauges of prior art devices. Such have not permitted free flow of
cut chips to pass easily into the gullet region and under the top plate 42 of the
cutter. This inability to free the kerf of debris has resulted in vibration, excessive
friction, and other impediments to efficient cutting.
[0033] The configuration of the present invention with a depth gauge portion which has angularly
disposed sides 58, 60 and a central region 56 at its greatest elevation intermediate
the width of the cutter edge permits free flow of chips past the depth gauge rear
edge side portions so that debris flows freely into the gullet region and under the
cutter top plate toward the chassis of the chain. This free flow of chips is further
enhanced by the positioning of the side edges and front edge. Further, friction is
minimized by minimizing the amount of the depth gauge which engages the kerf and debris
within the kerf.
[0034] It will be seen that central portion 56 is the highest and rearwardmost portion of
the depth gauge and that remainder portions of the depth gauge incline downwardly
and forwardly therefrom.
[0035] Although the bent-over depth gauge is described here on a cutter with a clipped heel,
it should be recognized that the depth gauge configuration can be used in cutters
without a clipped heel. The depth gauge of the present invention provides many operational
benefits independently of, as well as in conjunction with, a clipped heel configuration.
[0036] Figs. 5-7 illustrate another embodiment of the invention. A cutter 12a is illustrated
having a cutter portion 40a with a forwardly facing cutting edge 44a.
[0037] A depth gauge portion 46a is mounted on the front end of the body portion of the
cutter and is bent over at a substantial angle relative to the plane of the body portion.
It has a substantially planar upper surface 48b which is inclined downwardly on progressing
forwardly in the cutter.
[0038] The depth gauge portion 46a illustrated in Figs. 5-7 is multi-angular, and in this
embodiment is substantially hexagonal.
[0039] The configuration of the depth gauge 46a is somewhat similar to that previously described
for depth gauge 46, except that in this configuration, rather than having a convexly
curved outer edge region 70 between edges 60 and 66, there is a substantially flat
side 70a provided between side edges 60a, 66a.
[0040] In operation of a saw chain having a cutter constructed as illustrated, as the saw
chain is driven forwardly the depth of cut is controlled by depth gauge portion 46
leading cutting edge 44. The depth gauge portion having the configuration illustrated
provides effective depth gauge control, chain stability and kickback minimization
while permitting chips produced in the kerf of the work piece to flow freely past
the depth gauge and into the chassis region of the chain underlying the bent-over
cutter portion 42 of the cutter.
[0041] Further, with the clipped heel portion of the cutter, and a connector link on the
opposite side with a clipped heel portion paralleling the clipped heel of the cutter
as illustrated for link 18 in Fig. 1, such is able to rock rearwardly in the articulated
chain to reduce vibration. When this occurs the effective depth gauge setting 74 is
reduced to reduce vibration in the chain. The configuration of the bent-over depth
gauge acts in conjunction with the clipped heel portion to provide lateral stability
in the chain should such rocking occur. Explaining further, previous cutting chains
which may have had clipped heel portions have included a generally planar upright
depth gauge which produced very narrow contact with the work piece. This could allow
rotation of chain parts about the central axis extending longitudinally of the chain.
With the present depth gauge configuration, having a width which is major portion
of or greater than the width of the cutter, the depth gauge will engage the kerf to
provide greater stability, and reduce the tendency of the chain parts to rotate about
the central axis of the chain.
[0042] The bent-over depth gauge design of the present invention provides sufficient width
to produce kickback control for safety, while still producing improved chip flow.
[0043] It shall be noted that the two diverging sides 58 and 60 of the rear edge extend
forwardly and downwardly with respect to the cutting edge, whereby thus none of these
sides extends perpendicular to the plane 33 of the body portion.
[0044] While a preferred embodiment of the invention has been disclosed herein, it will
be apparent to those skilled in the art that changes and modifications may be made
without departing from the spirit of the invention.
1. Cutter (12, 14) for an endless cutter device (10) movable along a path for cutting
a kerf in a work piece, said cutter in an upright position comprising:
a body portion (32) disposed in a substantially upright plane (33) and having forward
(32b) and rearward (32a) regions,
a cutter portion (40) on the rearward region of the body portion having a forwardly
facing cutting edge (44) extending transversely of said plane having a selected width
(47) as measured normal to the plane of the body portion and disposed at a selected
elevation above the body portion, and
a depth gauge portion (46) on the forward region of the body portion, said depth gauge
portion comprising a plate portion (48) bent over at substantially right angle relative
to the plane of the body portion and having an upper surface (48a) inclined downwardly
from a rearwardly facing rear edge (56) of the plate portion which is disposed at
an elevation adjacent but below the elevation of the cutting edge to a forwardly facing
front edge (68) of the plate portion which is disposed at a lower elevation, said
depth gauge portion having a maximum width region which has a width (71) as measured
normal to the plane of the body portion which is at least as great as the width of
the cutting edge.
2. Cutter according to claim 1, wherein the cutter portion and the depth gauge portion
have free side regions that extend transversely beyond the plane of the body portion
and the free side region (70) of said depth gauge portion extends a distance (73)
equal to or greater than the distance (45) of said cutter portion beyond the plane
of the body portion.
3. Cutter according to claim 1, wherein said cutter portion comprises a cutter plate
portion (42) bent over at a substantial angle relative to and extending a first distance
(45) transversely of and beyond the plane of the body portion, and said depth gauge
portion extends transversely of and beyond the plane of the body portion a second
distance (73) equal to or greater than said first distance.
4. Cutter according to claim 1, wherein the maximum width region of the depth gauge portion
is disposed intermediate the front and rear edges, and said depth gauge portion has
opposed side edges (64, 66) which extend forwardly from said maximum width region
and converge toward each other as they extend forwardly therefrom.
5. Cutter according claim 4, wherein both of the side edges (64, 66) converge toward
the centre plane of the body on extending forwardly from the maximum width region.
6. Cutter according to claim 4, wherein one of said edges (66) converges toward the centre
plane of the body portion at an angle in a range of 35 degrees to 80 degrees.
7. Cutter according to claim 4, wherein the front edge (68) of the depth gauge extends
between said opposed side edges and has a width as measured normal to the plane of
the body portion which is narrower than said cutting edge.
8. Cutter according to claim 7, wherein the width of said front edge (68) is a minor
portion of the width of the cutting edge.
9. Cutter according to claim 1, wherein the maximum width region of the depth gauge portion
is disposed intermediate the front and rear edges, and said rear edge has a central
portion (56) nearest said cutting edge and a side portion (60) which extends forwardly
and downwardly from said central portion toward said maximum width region at an angle
relative to the plane of the body portion
10. Cutting chain (10) comprising a plurality of pivotally interconnected links including
cutter links (12, 14)with a cutter link in said chain in an upright position comprising:
a body portion (32) disposed in a substantially upright plane and having forward (32b)
and rearward (32a) regions,
a cutter portion (40) on the rearward region of the body portion having a forwardly
facing cutting edge (44) extending transversely of said plane having a selected width
(47) as measured normal to the plane of the body portion and disposed at a selected
elevation above the body portion, and
a depth gauge portion (46) on the forward region of the body portion, said depth gauge
portion comprising a plate portion (48) bent over at substantially right angle relative
to the plane of the body portion and having an upper surface (48a) inclined downwardly
from a rearwardly facing rear edge (56) of the plate portion which is disposed at
an elevation adjacent but below the elevation of the cutting edge to a forwardly facing
front edge (68) of the plate portion which is disposed at a lower elevation, said
depth gauge portion having a maximum width region (71) which has a width as measured
normal to the plane of the body portion which is at least as great as the width of
the cutting edge.