Depth gauge for a cutter

A depth gauge leading the cutting edge in a cutter device has a body portion disposed in a substantially upright plane. The depth gauge includes a top plate portion cantilevered laterally over the body. A juncture section joins the depth gauge plate portion to the body of the cutter and is deformed intermediate its front and rear ends to strengthen the depth gauge against breakage.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to an improved depth gauge for a cutter 
device. 
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 producing 
efficient cutting and reducing the possibility of kickback during 
operation of the saw on which the chain runs. 
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. Pat. No. 4,353,277. Others 
have included bent over depth gauge portions such as disclosed in U.S. 
Pat. Nos. 5,085,113 and 4,989,489 to Pinney, U.S. Pat. No. 4,911,050 to 
Nitschmann and U.S. Pat. No. 4,841,825 to Martin. 
The single thickness upright depth gauge as illustrated in U.S. Pat. No. 
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 U.S. Pat. Nos. 
4,911,050; 4,989,489; and 5,085,113 generally have substantially 
rectangular configurations as viewed in plan, and are susceptible to 
breakage. 
An object of the present invention is to provide a novel depth gauge 
leading a cutter edge which overcomes the disadvantages of prior devices. 
It has been found that prior cantilevered bent over depth gauges may be 
subject to failure in the region of the bend line, or juncture section, 
joining the cantilevered depth gauge plate to the body portion of the 
cutter. Failure often will begin as cracks on the inner side of the bend 
at the opposed front and rear free ends of the bend. These cracks then 
migrate inwardly toward the central region of the bend in the depth gauge, 
producing failure. 
It has been discovered that two design modifications may be made to 
minimize, or eliminate, this problem. First is by producing a larger 
radius juncture section joining the body portion and depth gauge plate 
portion. Second, it has been found that benefits arise by deforming the 
depth gauge material in the bend, or juncture region, inwardly toward the 
center of bending in a region intermediate the forward and rearward ends 
of the depth gauge. 
The deformation may be in the form of an indentation in the laterally 
outwardly facing side surface of the juncture section which deforms 
material inwardly on the underside of the cantilevered depth gauge plate 
portion. This shifts the neutral axis of the juncture section inwardly 
toward the center of bonding, such that the stresses will be significantly 
reduced at the inner sides of the bend at opposed free ends of the bend to 
eliminate or minimize previously-experienced failure. 
An added benefit and advantage occurs from providing an indented 
deformation on the laterally outwardly facing side of the juncture 
section. Added side plate relief is provided on the depth gauge forwardly 
of its rearwardmost edge to reduce drag and friction in the kerf cut, thus 
to provide more effective and efficient action for the depth gauge.

DESCRIPTION OF A PREFERRED EMBODIMENT 
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. 
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. 
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. 
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 11/2.degree. to 5.degree. 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 0.08 inch. This distance will vary in relation to the size and style of 
cutter. 
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. 
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. 
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. 
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 the 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. 
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. 
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. 
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. 
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 (as measured along a line 
normal to plane 33) 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. 
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. 
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. 
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. 
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. 
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 0.degree. to 
30.degree. (preferably 10.degree. to 30.degree.), angle 86 in a range of 
10.degree. to 60.degree., and included angle 88 in a range of 
100.degree.-170.degree., and preferably 110.degree. to 160.degree.. Angle 
94 is in a range of 10.degree.-55.degree. and angle 96 in a range of 
0.degree. to 15.degree.. The downward slope 98 of the upper planar surface 
48a as shown in FIG. 2 is in a range of 15.degree. to 35.degree.. 
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. 
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. 
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. 
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. 
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. 
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. 
The depth gauge portion 46a illustrated in FIGS. 5-7 is multi-angular, and 
in this embodiment is substantially hexagonal. 
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. 
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. 
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. 
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. 
Another embodiment of the invention is illustrated in FIGS. 8-14. Here a 
cutter device, or cutter link, 110 is shown having a main body section, or 
body portion, 112. The body portion 112 is substantially planar having 
opposed face surfaces 112a, 112b and is shown with a substantially upright 
central plane 114. The cutter is formed as a monolithic, or integral, 
whole from plate metal stock having selected thickness as indicated 
generally at 116 between its opposed face surfaces. It has a cutter 
portion 118 extending upwardly from the rear portion of body portion 112 
and a depth gauge portion, or depth gauge, 120 projecting upwardly from a 
forward region of the body. 
The cutter portion has an upright side plate portion 122 with an upright 
leading sharpened cutting edge 122a. Cantilevered from side plate portion 
122 and extending transversely of plane 114 is cutter top plate 124 having 
a leading top plate cutting edge 124a which extends transversely of plane 
114. 
The depth gauge has a bent over depth gauge plate portion 126 which is 
cantilevered above the body portion and extends at a substantial angle 
relative to and transversely of plane 114. The depth gauge plate portion 
illustrated is disposed substantially at a right angle relative to plane 
114. 
As is best seen in FIG. 8 depth gauge portion 126 has opposed, 
substantially parallel upper and lower surfaces 126a, 126b. The top 
surface 126a is substantially planar and inclines substantially 
continuously downwardly from the rearward edge 126c toward the forward 
edge 126d of the depth plate portion. 
The depth gauge plate portion is interconnected to the body portion by a 
juncture section 132. The juncture section 132 has an outer face surface 
at 132a and an inner face surface 132b. These outer and inner face 
surfaces 132a, 132b, respectively merge with top surface 126a and bottom 
surface 126b of the depth gauge portion. 
The juncture section may be formed in a larger radius bend, or curve, then 
previous bent over depth gauges to strengthen the part and minimize 
breakage. Inner radius R1 (FIG. 11) may be in a range of 0.5 to 2.0 times 
thickness 116. 
Referring to FIGS. 9 and 13, the juncture section has rear and front ends 
denoted generally at 132c, 132d. The length of the juncture section 
between its opposite ends 132c, 132d is denoted by dimension line 136. 
This generally will be several times the thickness 116 of the part. 
As viewed from above in FIGS. 9 and 13, a portion of the juncture section 
intermediate its ends is deformed, or indented, laterally inwardly toward 
the center of bending and toward plane 114 from remainder portions of the 
juncture section. This deformed region, or section, intermediate ends 
132c, 132d is indicated generally at 140. Section 140 produces a concave 
outer curvature section whereby the portion of outer surface 132a adjacent 
rear edge 132c is the region of the depth gauge portion farthest to one 
side of plane 114, with remainder portions of the juncture section 
forwardly thereof spaced inwardly toward central plane 114 therefrom to 
provide added side plate relief for the depth gauge to minimize frictional 
engagement with the side edge of the kerf cut by the cutter. 
The deformed region or section has, at its approximate fore-to-aft central 
region, an inner radius of curvature R3 (see FIG. 12) which is greater 
than R1. 
Referring to FIGS. 10-13, the deformed region 140 of the juncture section 
projects laterally from the inner face of body portion 112 and connects 
to, or joins integrally with, the underside 126b of the depth gauge. This 
inwardly projecting portion of the deformed region of the juncture section 
140 produces a supporting portion 142 which underlies and provides support 
for the cantilevered depth gauge portion. 
As is seen in FIG. 13, the deformed portion 140 has a length denoted 144 
and projects inwardly from remainder portions of the inner surface of 
juncture section a distance indicated generally at 146. This is generally 
the same distance by which the juncture section is indented from the other 
side as indicated at 147. As is seen in FIG. 13, the outwardly facing 
surface of the juncture section is generally concavely curved, whereas its 
inner side is convexly curved. Although a variety of different deformed 
cross sections may be used (i.e. angular, multi-angular, various curve 
forms, etc.) it has been found preferable to place the deformation 
substantially centrally between the front and rear edges of the juncture 
section and to make the deformation substantially curvilinear throughout 
to minimize regions of stress concentration. 
The manufacture of the cutter with the depth gauge as shown in FIGS. 8-13 
is somewhat similar to that previously described. For example, metal plate 
stock is cut to a defined outer configuration and then deformed to produce 
the bent over hooded cutter portion. Also the depth gauge of the form 
illustrated is bent over in the forming process. During this forming 
process, an indentation 140 is impressed on the outside of the juncture 
section to a depth indicated generally at 147 to form the underlying 
deformation 142 projecting inwardly and supporting the depth gauge top 
plate. 
In the forming process, the general curvature of the bent over juncture 
section adjacent its front and rear ends is as indicated at R1 in FIG. 11 
(inner radius of juncture section) and may be approximately equal to the 
thickness 116 of the plate material. R1 preferably may be in a range of 
from 0.5 to 2.0 times thickness 116. 
Referring to FIG. 13, as seen from above indentation 140 is formed at its 
maximum indentation adjacent the depth gauge plate portion 126 with a 
radius R2 generally equal to or greater than the thickness 116 of the 
part. The indentation distance 147 preferably may be in a range of about 
0.1 to 1.0 times thickness 116, and more preferably about 0.30-0.40. This 
may vary in relation to the form of deformation chosen for a specific 
part. The length of juncture section 132 has been previously denoted by 
dimension line 136. The general length of the deformed portion on the 
inner side of the depth plate gauge is noted at 144. This is deformed 
inwardly from remainder portions of the juncture section in a convex curve 
a distance denoted generally at 146. This is similar to the depth of the 
concave curve on the other side denoted by 147. Thus, the deformed portion 
may extend laterally of remainder portions of the juncture section in a 
range of from 0.1 to 1.0 times thickness 116. 
The length of the deformation as measured by dimension line 144 may be of 
variable length, but has been found to work well in a range of 0.25 to 
0.67 times length 136. Dependent on length 136, length 144 may be in a 
range of from 1 to 5 times thickness 116. As seen in FIG. 13 the deformed 
section preferably is spaced longitudinally of the part from the front and 
rear ends 132c, 132d, by distances noted 144a, and 144b. Distances 144a, 
144b each preferably are at least 0.1 times thickness 116. 
As seen in FIG. 12 an inner radius R3 is denoted for the inner side of 
deformed portion 140. R3 is greater than R1 and preferably may be in a 
range of from 1 to 4 times thickness 116. 
An exemplary depth gauge juncture section which has been tested and shown 
to work well, has a material thickness of 0.050 inch, an inner radius R1 
for the bent over juncture section of approximately 0.050 inch, 
deformation dimensions 146 and 147 of approximately 0.015 inch, a length 
136 of approximately 0.230 inch and a length 144 of approximately 0.080 
inch. 
As is seen in the illustrations, attempts are made to maintain 
substantially curvilinear configuration for the deformation throughout to 
minimize stress regions. 
The depth gauge just described in regard to the embodiment illustrated in 
FIGS. 8-13 operates substantially as those in embodiments previously 
described herein. However, it has been found that the embodiment 
illustrated in FIGS. 8-13 has greater resistance to breakage. 
During operation a variety of loads are imposed on the depth gauge portion. 
Due to such loading it has been found in prior bent over depth gauges 
(without a deformed support section as provided here) that failure occurs 
with cracks initiating at the front and rear corners of the inside surface 
of the bent over portion where the depth gauge top plate joins with the 
body portion or juncture section. The present design, with a larger radius 
juncture section and engineered, or deformed, cross section is designed to 
displace the region of highest stress inwardly from the free front and 
rear end corners to reduce failure due to breakage. 
First, by increasing the radius of curvature of the juncture section, 
stress points are reduced during operation from those found in prior 
devices. 
Secondly, the engineered or deformed juncture section is designed to 
provide added support for the depth gauge and to move the regions of 
highest stress away from the free edges, or ends, of the bend section. 
This minimizes, or dramatically reduces, the stresses that previously 
produced cracking and failure at the free ends, or edges, of the bend 
section in prior devices. 
One reason for the success of this structure possibly can be described by 
comparing the cross sections illustrated in FIGS. 14 and 15. FIG. 14 is an 
example of the cross section of a deformed juncture section according to 
an embodiment of the present invention. FIG. 15, on the other hand, is a 
cross section taken at a similar point for a bent over depth gauge 
construction 148 without the deformed, or engineered, cross section. 
FIGS. 16 and 17 are simplified illustrations at the regions at which 
sections 14 and 15 respectively are taken in structures as described. Each 
is in the form of a curved beam having a base plate portion 112, a 
cantilevered top plate 126 and a juncture section 132. The sections 
illustrated in FIGS. 14 and 15 are highlighted in cross section in FIGS. 
16 and 17, respectively. 
It is important to note that these are what are referred to as "curved 
beams" in engineering terms and they have somewhat different 
characteristics when placed under load than do straight beams. 
In operation of a saw chain using a cutter with a bent over depth gauge as 
illustrated, it is believed that loads directed as illustrated at L1 and 
L2 in FIGS. 16 and 17 are imposed on the depth gauge top plate. Load L 
produces a compressive, or downwardly, directed force. Load, or force, L2 
occurs in the opposite direction. Force L2 imposed on the cantilevered 
depth gauge top plate is the force which induced failure by cracking which 
began at the front and rear ends of the underside of the bent over 
juncture section in previous bent over depth gauges and then migrated from 
the front and rear ends toward the middle of the juncture section. 
The centroid, or centroidal axis, of the structure of FIG. 14 is indicated 
at 115. The centroid, or centroidal axis, for the part in FIG. 15 is 
indicated generally at 150. 
The two sections will be discussed as being cross sections of curved beams, 
with the distribution of stresses over their cross sections under bending 
loads produced by forces applied to the depth gauge attached thereto such 
as L1 and L2. 
If the sections illustrated in FIGS. 14 and 15 were portions of straight 
beams their neutral axes would be considered generally to coincide with 
their centroid, or centroidal axis. However, in computation of 
characteristics of curved beams the neutral axis shifts inwardly toward 
the center of curvature by a distance which relates to the severity, or 
degree, of curvature of the beam. 
In FIG. 15, the neutral axis of the section is indicated generally at 152 
offset toward the center of curvature from centroid 150. With a load 
applied to top plate 126 as indicated at L1 or L2 in FIG. 17, the stress 
concentration in the section will be distributed generally as indicated at 
151 at the left-hand region of FIG. 15. As seen, the region of zero stress 
is at neutral axis 152. The material on one side of the neutral axis 
generally will be under tension and the other side is under compression 
due to forces imposed on the cantilevered depth gauge. On either side the 
stress will be highest at the face of the part and declines to zero at the 
neutral axis, but the greatest stress will be at the surface of the 
inside, concave bend radius. In practice, especially in die cut parts 
where micro-cracks at sheared edges present stress concentrations, corners 
may be the source of initiation of fatigue cracks which then may migrate 
inwardly. 
Referring to FIG. 14, the deformation of the central portion of the 
juncture section causes the neutral axis 154 to shift in the direction of 
the center of curvature and may be so shifted that the neutral axis 154 
lies generally along the face of the non-deformed regions of the juncture 
section at opposite ends of sections 140, 142. 
With this structure, the stress induced in the part by loading of the bent 
over depth gauge is indicated at 153 at the left side of FIG. 14. As with 
the stress diagram in FIG. 15 the maximum stress is seen to occur at the 
extreme outer faces of the part. However, here the neutral axis 154 has 
been shifted generally to the inner faces of the forward and rearward ends 
of the juncture section directed toward the center of curvature for the 
juncture section, and thus there is virtually no stress in either a 
compressive or tensile mode at the inner faces of the front and rear end, 
or edge, regions. Since the maximum stress is shifted to the central 
deformed region, where no micro-cracks or sheared edge conditions exist, 
more loading, or work, is necessary to cause cracks to initiate in this 
central region than at the corners. Thus the reliability and resistance to 
breakage for the part is notably improved. 
Certain texts on curved beam calculations note that it is important to 
distinguish between whether the element involved is a thick member or a 
thin member. Certain texts have noted that when the mean radius of 
curvature is about ten times the thickness, or depth, of the cross section 
the member is considered thin and it is generally not critical to factor 
in curved beam theories. Some even have gone down to six times the depth 
or thickness without finding undue error in calculations. However, if the 
radius of curvature is less than six times the depth or thickness of the 
material, curved beam theories of calculations must be factored into 
account and such produce movement of the neutral axis as described above. 
The radius of curvature as noted for applicants' invention as set out 
herein establishes that it is in what might be considered a tight radius 
curve when dealing with curved beam calculations. Since it is a tight 
radius curve the stresses on the inside of the curve normally might be 
increased to two to three times higher than normal due to curved beam 
calculations. However, by providing the engineered, or deformed, section 
for the part in the manner described to move the neutral axis toward, or 
to, the inside edges of the front and rear ends of the juncture section, 
the effect of the stress multiplier feature is reduced, or eliminated, at 
these points. 
FIG. 18 illustrates another embodiment of the subject invention. At 210 is 
noted a cutter link somewhat similar to that previously described in 
regard to FIG. 9, having a main body section, or portion, 212. The body 
portion 212 is substantially planar and is shown with a substantially 
upright central plane 214. The cutter is formed as a monolithic, or 
integral, whole from plate metal stock having selected thickness 
throughout. It has a cutter portion 218 extending upwardly from the rear 
portion of the body portion 212 and a depth gauge portion, or depth gauge, 
220 projecting upwardly from a forward region of the body. 
The depth gauge has a depth gauge plate portion 226 bent over in a 
cantilevered position above the body portion and extending at a 
substantial angle relative to and transversely of plane 214. The 
orientation of depth gauge plate portion 226 is substantially similar to 
that illustrated in FIGS. 8-12 for a prior embodiment. It has a deformed 
side portion 240 performing the same function as that set out above in 
regard to the embodiment described in regard to 110. 
In this embodiment shown in FIG. 18 the rearwardmost portion 226c of the 
depth gauge portion is on the same side of central axis 214 as cutting 
corner 218a of the rearwardly-mounted cutter portion 218. Its rearwardmost 
edge 226d slopes forwardly and downwardly from rearwardmost region 226c to 
a side portion 226e. A forward region of the depth gauge 226f is more 
scalloped in configuration than previously-described embodiments and 
reduces the amount of material existing in the depth gauge plate. 
It has been found that the configuration of the depth gauge plate as 
illustrated in FIG. 18 maintains adequate kick-back protection while 
improving cutting capabilities of the cutter. In essence, it merely omits 
some of the material found in other links described herein. 
Referring to FIGS. 19-21, another embodiment of the invention is 
illustrated. Here, a cutting chain 250 has alternate left- and right-hand 
cutter links, with a left-hand cutter link 252 being illustrated here. The 
cutter link 252, has a planar upright body portion 254 with a pair of 
bores extending therethrough to receive rivets 256. The rear-end region of 
the body has a cutter portion 260 thereon including a top plate 262 with a 
forwardly-facing top plate cutting edge 262a. A side plate portion 266 
joins body portion 254 and top plate 262. The side plate has a 
forwardly-facing side plate cutting edge 266a, which joins with top plate 
cutting edge 262a. 
The forward portion of cutter 252 does not have an upwardly-projecting 
depth gauge portion thereon. 
Connected to cutter link 252 through rivets 256, and disposed on the 
longitudinal centerline 268 of the chain are leading and trailing center 
drive links 270, 272, respectively. 
Secured to the sides of center drive links 270, 272 opposite cutter 252 and 
also pivotally mounted on rivets 256 is a side tie strap 276. The tie 
strap 276 opposite cutter 252 has a substantially planar body portion 278, 
with an upright central plane 279. A depth gauge portion 280 extends 
upwardly from body portion 278 to lead the top plate and side plate 
cutting edges 262a, 266a. 
Depth gauge portion 280 is structured somewhat similarly to depth gauge 
portion, or depth gauge, 120 previously described in relation to the 
embodiment illustrated in FIGS. 8-13. However here, rather than extending 
initially upwardly and outwardly from the body portion 278 in the 
direction of side plate cutting edge 266a, as in the prior embodiment, it 
projects outwardly oppositely therefrom as illustrated in FIGS. 20 and 21. 
It then progresses to a bent over depth gauge plate portion 282 which is 
cantilevered above the body portion and extends at a substantial angle 
relative to and transversely of the plane of the body portion and across 
centerline 268. Generally it will extend substantially normal to the plane 
of the body portion. Again, the juncture section 284, between the body 
portion and the depth gauge plate portion has an outer surface 284a and an 
inner surface 284b which respectively merge with the top and bottom 
surfaces of the depth gauge portion, respectively. 
As viewed in FIGS. 20, 21 a portion of the juncture section intermediate 
its ends is deformed, or indented, laterally inwardly toward the center of 
bending and toward the plane of body 278 from remainder portions of the 
juncture section, as was previously described for the embodiment 
illustrated in FIGS. 8-12. The top plate portion of the depth gauge may be 
extended sufficiently to the side of the plane of the body toward side 
plate cutting edge 266a, that it provides not only depth of cut control 
for the top plate cutting edge 262a, but also for the side plate cutting 
edge. 
The general structure and function of the depth gauge portion mounted on 
side link 276 is similar to that previously described in conjunction with 
the embodiment illustrated in FIGS. 8-12. It has been found that this 
structure, of placing the leading depth gauge on a side tie strap opposite 
a cutter link which does not have its own depth gauge, can provide very 
efficient cutting. 
Referring to FIGS. 22 and 23, yet another embodiment of the invention is 
illustrated wherein a segment of chain 300, again has a cutter link as 
previously described at 252 lacking a monolithically, or integrally, 
formed leading depth gauge portion. A plain tie strap 304 is disposed 
opposite the cutter link. Here, a leading center drive link 310 has a 
substantially planar upright body portion 312 with a depth gauge portion 
314 extending upwardly from the rear end portion thereof. As seen in FIGS. 
22 and 23, the structure and general positioning of depth gauge 314 on the 
center drive link is similar to that described above in relation to depth 
gauge 280 in the embodiments of FIGS. 19-21. The cantilevered depth gauge 
plate portion and its associated juncture portion have a deformation as 
previously described to provide additional strength and resistance to 
breakage. 
Optionally, the depth gauge portions of the embodiments of FIGS. 19-24 
could be bent-over in the direction opposite that illustrated, as could 
the earlier-described and illustrated embodiments. Further, although 
various depth gauge top plate configurations have been illustrated and 
described, the features of the present invention may be advantageously 
incorporated in cutters with different configurations, including, but not 
limited to square or rectangular. 
Additional uses of cutters and depth gauges according to various 
embodiments of the invention are illustrated in FIGS. 24 and 25. Here, the 
cutters and depth gauges are not mounted on a cutter chain for a chain 
saw. Instead, in FIG. 24, a circular saw disk 320, has left-and right-hand 
cutters 322, 324 secured thereto by rivets 326. These cutters may have any 
of the configurations illustrated and described herein or as covered by a 
following claim. 
FIG. 25 illustrates that a saw disk 330 may have formed on the periphery 
thereof (rather than merely being attached thereto) a plurality of cutters 
332, which are led by depth gauge portions 334. Again, these may be formed 
as described in any of the previously discussed embodiments, or any that 
are covered by the appended claims. 
Although the depth gauges, or depth gauge portions, shown herein have a 
variety of shapes, it should be understood that the deformed side plate, 
or juncture, portion providing the benefits set out above, may be used 
with depth gauges having a variety of other shapes. For example, but in no 
way to limit the scope of the invention, a bent over depth gauge using the 
improved deformed, or engineered section as described herein may have 
straight, curved, or multiangular leading and/or trailing edges or a 
variety of other configurations. 
While preferred embodiments of the invention have 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.