U.S. patent number 3,826,024 [Application Number 05/330,050] was granted by the patent office on 1974-07-30 for excavator tooth, holder and retainer.
Invention is credited to Gerald Alger Petersen.
United States Patent |
3,826,024 |
Petersen |
July 30, 1974 |
EXCAVATOR TOOTH, HOLDER AND RETAINER
Abstract
An excavating tooth holder has a recess receiving the proximal,
non-circular end of a tooth formed wth a groove to provide a
circular spindle forward of a shoulder. A staple-shaped retainer in
the holder has an inwardly disposed stretch which fits into the
groove and locks the tooth in place when the retainer is operative.
When the retainer is retracted, the inward stretch is lifted from
the groove, permitting the tooth to be removed. The shape of the
retainer and the opening in the holder in which it fits permit
lifting of retainer with removal of the retainer from the
holder.
Inventors: |
Petersen; Gerald Alger (06
Vence, FR) |
Family
ID: |
26910339 |
Appl.
No.: |
05/330,050 |
Filed: |
February 6, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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215739 |
Jan 6, 1972 |
3751834 |
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Current U.S.
Class: |
37/458; 279/79;
24/573.09; 411/516 |
Current CPC
Class: |
E02F
9/2841 (20130101); Y10T 279/17786 (20150115); Y10T
24/45005 (20150115) |
Current International
Class: |
E02F
9/28 (20060101); E02f 009/28 () |
Field of
Search: |
;37/142 ;279/79
;287/2.5SL ;24/211K |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Crowder; Clifford D.
Attorney, Agent or Firm: Caplan; Julian
Parent Case Text
This invention is a continuation-in-part of U.S. Patent application
Ser. No. 215,739 filed Jan. 6, 1972, now U.S. Pat. No. 3,751,834.
Claims
What is claimed is:
1. A holder for a tooth comprising a member formed with a recess
shaped to receive the proximal end of a tooth opening inward from
one end of said member in a first direction, said holder formed
with an opening spaced back from said one end, said opening
extending inward from a first surface of said holder generally
perpendicular to said first direction to a second surface of said
holder opposite said first surface, at least one wall of said
opening comprising a continuation of a wall of said recess, said
one wall of said opening having a straight first portion parallel
to said first direction, a second portion adjacent said first
surface laterally offset with respect and approximately parallel to
said first portion, a shoulder interconnecting said first and
second portions, said first surface formed with a depression
intersecting said opening and extending transverse to said first
direction having a bottom spaced outwardly of said shoulder, said
second surface formed with an outward flared extremity comprising a
continuation of said first portion.
2. In combination, an excavating tooth having a proximal portion of
non-circular cross-section and a distal portion formed with a
cutting edge, a tooth holder formed with at least one recess
complementary to said proximal portion and opening inward from the
forward end of said holder and extending inward from said forward
end in a first direction, said recess having first side walls
extending approximately parallel to said first direction, and a
retainer, said retainer having a pair of legs and a connecting
portion connecting one end of each said leg, said retainer being
formed of a resilient material to resist movement of said legs
toward and away from each other, said retainer being slideable in
said holder between operative and retracted positions, said holder
formed with an opening extending from a first side of said holder
to the second side of said holder opposite said first side, said
opening having opposed second side walls extending approximately
parallel to said first direction, said opening being spaced back
from said forward end, said opening extending parallel to a plane
generally perpendicular to said first direction, at least one said
second side wall having a first portion, a second portion laterally
offset with respect and approximately parallel to said first
portion and a first shoulder interconnecting said first and second
portions, said proximal portion of said tooth formed with a notch
and having a second shoulder rearward of said notch, at least one
leg of said retainer extending along one said second wall adjacent
said first and said second sides and into said notch when said
retainer is in operative position and abutting said second shoulder
to restrain said tooth against dislodgement from said holder, said
one leg being movable out of said notch without total removal of
said one leg from said holder when said retainer is in retracted
position, said legs biased to diverge from each other so that said
legs engage said second walls to resist unintentional movement of
said retainer, said one retainer leg being entirely inside said
holder when said retainer is in operative position, said retainer
being assembled with said holder when either in retracted or in
operative position, at least one leg of said retainer having an
upper portion, a lower portion offset laterally relative to said
upper portion and a short interconnection joining said upper and
lower portions, said interconnection being located approximately
midway of the length of said one leg and being at all times within
said opening when said retainer is either in operative or in
retracted positions, said first shoulder engaging said
interconnection to limit outward movement of said retainer when
said retainer is in retracted position.
3. The combination of claim 2 in which said proximal portion of
said tooth forwardly of said notch has a first surface extending in
said first direction, a second surface parallel to said first
surface, and two third surfaces intersecting said first and second
surfaces, at least one said third surface having an outwardly
protruding ear extending in said first direction, said ear being
intermediate said first and second surfaces and having both its
width and its breadth substantially less than one-half the distance
between said first and second surfaces, said third surface to
either side of said ear comprising a flat plane.
4. The combination of claim 2 in which the walls of said opening
diverge proceeding outwardly from said recess to permit dirt to
escape from said opening.
5. The combination of claim 4 in which at least one leg of said
retainer is bent outward into the diverging portion of said opening
to restrain unintentional withdrawal of said retainer.
6. The combination of claim 2 in which the ends of the legs of said
retainer are curled inward to facilitate movement of said retainer
within said holder.
Description
This invention relates to a new and improved chain-mounted trencher
tooth system and to a retainer for such teeth. For simplicity and
brevity, this system is referred to in this Specification and in
the claims as a "chain," but the term "chain" is intended to cover
other trencher systems, such as ladders, wheels and the like.
The present invention provides teeth mounted on a trencher machine
chain which dig a trench having vertical sides extending downward
from the surface, a horizontal shelf and a V-shaped bottom. The
V-shaped bottom is satisfactory for installation of drainage pipe.
The vertical sides and horizontal shelf are located at such depths
as required in the drainage system for the field in which the
trench is formed.
A further feature of the invention is the fact that the shape of
the trench accommodates continuous plastic pipes or short sections
of clay pipes or similar drainage pipes which are usually fed into
the trench automatically by the machine as it makes the trench.
Square pipes turned 45.degree. fit very satisfactorily into the
bottom of the trench.
A further feature of the invention is the fact that the teeth are
replaceably mounted in holders which are supported at their inner
ends by pins attaching the holders to links of the trencher chain.
The teeth are located rearwardly of the point of attachment of the
holder-supporting arm to the chain, as contrasted with conventional
trencher chain construction, so that the chain tends to pull the
tooth rather than push it. Each holder is attached to an arm, the
length of the arm and the disposition of the holders for the teeth
on the arms being varied at different positions along the section
of the chain. In one section of chain are a first tooth on each
side which digs the vertical side, the second tooth the horizontal
shelf, the third tooth the upper portion of the V-shaped bottom and
the fourth tooth the bottom of the V-shaped bottom. The sequence of
the teeth need not be in the order named, although this sequence is
convenient. The holders on the two sides are alternated so that the
first tooth on the right side digs first and then the first tooth
on the left side until the bottom of the trench is reached
whereupon the series is repeated. The holders are substantially
uniform in shape and only the arms connecting the holders to the
links of the chain are different. Further, the teeth themselves are
identical in all of the holders and the retainers likewise are
identical. Economy in manufacture is achieved by this
construction.
Another feature of the invention is the fact that the retainers are
so positioned relative to the holders that, as the chain revolves,
even at high speeds, the retainers do not tend to fall out of the
holders by centrifugal force. The angles at which the retainers fit
into the holders are such that centrifugal force tends to assist in
holding the retainers in place, yet the retainers are so located
that when it is necessary to replace a tooth the retainers can
easily be raised to free the tooth.
Still another feature of the invention is the fact that simple,
readily available tools such as screwdrivers may be used to retract
retainers. The teeth may be removed from their holders and replaced
by hand unless the teeth have rusted into the holders or some other
unusual conditions occur. The operation requires little time and
comparatively little skill of the workman. The fact that the tooth
may ordinarily be inserted and pulled out by hand is a distinctive
feature of this invention.
The retainer of the present invention is staple-shaped and the
tooth holder slidably receives the retainer. The tooth holder has a
recess which receives the shank or proximal part of the tooth in a
non-rotative mode and a portion of the proximal end of the tooth
adjacent to the rear is formed in a cylindrical spindle with a
shoulder rearward of the spindle. When the retainer is fully
inserted in an opening in the holder, the upper portion of the
retainer fits closely against the spindle portion and forwardly of
the shoulder, thereby retaining the tooth in place. On the other
hand, when the retainer is pulled partially outward to retracted
position, the upper portion of the retainer slides away from the
spindle portion and there is no engagement of the retainer in the
shoulder of the shank, thereby permitting the tooth to be lifted
out of the holder by hand and replaced.
It is, thus, a principal feature of the invention to provide a
retainer which is formed with offset legs so that the upper end of
each leg comprises a shoulder-engaging portion, which, when the
retainer is fully inserted in the holder, is operative and the
lower portion of the legs are offset outwardly relative to the
upper portions so that when the retainer is partially withdrawn the
lower portions of the legs do not fit ahead of the shoulder and the
retainer is inoperative. Further, the legs of the retainer are
formed so that they initially diverge, thereby requiring that the
legs be compressed toward each other for insertion into the opening
in the holder. The end of one leg of the retainer slants outward
and engages the diverging wall of the opening to prevent the
retainer from slipping to retracted position unintentionally.
Still another feature of the invention is the provision of an
internal shoulder in the opening of the holder into which the
retainer is inserted and which is engaged by the retainer and
limits outward movement of the retainer relative to the holder when
the retainer has been withdrawn to inoperative position.
A feature of the retaining means for the tooth is, therefore, rapid
installation and removal and secure holding of the tooth in place
against unintentional dislodgment. The retainer is inexpensive and
readily replaced if the original retainer is lost or damaged.
Other objects of the present invention will become apparent upon
reading the following specification and referring to the
accompanying drawings in which similar characters of reference
represent corresponding parts in each of the several views.
In the drawings:
FIG. 1 is a perspective view of a portion of a chain of a trencher
having a plurality of holders installed thereon in accordance with
the present invention.
FIG. 2 is a schematic sectional view of a trench formed in
accordance with the invention showing schematically the locus of
the teeth which form the various portions of the walls of the
trench.
FIG. 3A is a side elevational view of the first tooth of the
series.
FIG. 3B is an end elevation thereof.
FIG. 3C is a top plan thereof.
FIG. 3D is a view similar to FIG. 3B showing a modified holder for
a wider trench.
FIGS. 4A-D, inclusive, are views similar to FIGS. 3A-D
respectively, of the second tooth on the same side of the chain as
the first tooth.
FIGS. 5A-C are views similar to FIGS. 3A-C of the third tooth of
the series.
FIG. 6 is a view similar to FIG. 5B of the fourth tooth of the
series.
FIG. 7 is a view similar to FIG. 3C broken away to reveal internal
construction.
FIG. 8 is a sectional view taken substantially along the line 8--8
of FIG. 7.
FIG. 9 is a sectional view taken substantially along the line 9--9
of FIG. 7.
FIG. 10 is a perspective view of a retainer used in the present
invention.
Directing attention to FIG. 2, a trench 21 formed in accordance
with the present invention is illustrated more or less
schematically. Said trench, immediately below the surface has
vertical side walls 22L and 22R, the depth of penetration of these
walls depending upon the control of the trencher machine on which
the system of the present invention is installed. The teeth are
mounted on chain 27 in a sequence, which is subject to variation in
the order the teeth are positioned. One sequence is illustrated and
described, it being understood that the terms "first", "second,"
etc. may be changed. As set forth in the claims hereof the series
of chain links may be altered in the order of their sequence. The
walls 22L and 22R are cut by the first teeth of the series of teeth
making up the system of the present invention designated as 32aL
and 32aR, respectively. Below walls 22L and 22R are horizontal
shelves 23L and 23R which are cut by teeth 32bL and 32bR,
respectively. Sloping downward on either side and meeting at an
apex in the middle of the trench are, on the left side, sections
24L, 26L and on the right side 24R and 26R disposed at a 90.degree.
angle and cut by teeth 32cL, 32dL, 32cR and 32dR, respectively. The
V-shaped bottom of the trench accommodates a pipe for drainage or
irrigation and the depth of the side walls 22 is subject to
considerable variation.
Directing attention to FIG. 1, the chain 27 which cuts the trench
21 is partially illustrated. In the section illustrated in FIG. 1
there are eight tooth holders 31 in a sequence, four on each side,
each holding a tooth 32. Tooth 32aR is the leading tooth and cuts
one of the side walls of the trench 21 and the other teeth are
located rearwardly thereof. It will be understood that the series
of teeth is repeated several times, the chain being made up of a
plurality of such series, the number of series depending upon the
length of the chain. The chain 27 passes around sprockets (not
shown) at either end of the machine, one of the sprockets being a
drive sprocket for the chain. The angle which the chain 27 assumes
relative to the horizontal controls the depth of the trench dug or
in other words the depth of the side walls 22R, 22L.
Each holder 31 is connected by means of arm 33 to a link portion 34
having two apertured disks 35 through which pins 29 fit to
pivotally connect the link portions 34 to the adjacent links 28 of
the chain. The lengths of arms 33 and the disposition of holders 31
determine the cutting positions of the teeth 32 mounted
therein.
Each tooth 32 has a distal portion 36 formed with a cutting edge
37. The top 39 of the tooth has a flat central rib 41 and the top
39 diverges outwardly rearwardly relative to bottom 38. Bottom 38
has a central depression 40 which increases in depth proceeding
rearwardly. Rib 41 merges with a transverse protuberance 42 across
the width of the tooth located immediately forwardly of holder 31
and limiting inward movement of the tooth relative to the holder.
There is a corresponding protuberance 44 on bottom 38. The side
edges 43 of the tooth are substantially vertical and transverse to
cutting edge 37.
The proximal end 46 of tooth 32 in its forward area is formed with
a trapezoidal portion 47 preferably formed with outward protruding
ears 48. It is important that the ears 48 prevent rotation of
proximal end 46 and assist in locating the tooth in its holder. The
back end 49 of proximal end 46 may be circular in cross-section and
immediately forwardly thereof is a cylindrical spool 51 of lesser
diameter than back end 49 there being a shoulder 52 at the forward
end of back end 49 which cooperates with the retainer 66
hereinafter described to limit withdrawal of the tooth 32 when the
retainer 66 is in place. As best shown in FIG. 7, distal end 36 is
disposed at an angle relative to proximal end 46, or in other words
the bottom surface 38 diverges outwardly relative to the chain on
which the holder 31 is mounted. Thus the cutting edge 37 provides
clearance for the holder 31. It should also be noted that the
holder 31 is located rearwardly of the forward disk 35 of link
portion 34 and that the cutting edge 37 of the tooth 32 held
therein is disposed somewhat rearwardly of the forward end of link
portion 34. Thus the chain tends to pull the tooth 32 forwardly
behind it rather than pushing the tooth 32 ahead of the link to
which it is attached as in other trencher chain constructions.
Holder 31 is formed with a recess 56 extending from the forward end
of the holder rearwardly, said recess 56 being substantially
complementary to the proximal end 46 of tooth 32. At about the
middle of holder 31, and in alignment with spool portion 51 of
tooth 32 when the tooth is fully seated, is an opening 57 extending
transversely through holder 31. Shown in the bottom of FIG. 9 but
frequently in the top of the holder 31 is a depression 58, there
being a bottom 60 which limits inward movement of the retainer 66
as hereinafter appears. Below bottom 60 are inwardly offset walls
61 and beyond walls 61 are outwardly offset walls 62, there being
shoulders 63 at the merger of the inward and outward walls, said
shoulders 63 limiting withdrawal of retainer 66 as hereinafter
appears. On the side opposite depression 58 the opening 57 has
outwardly flared extremities 64 which assist in expelling dirt and
also function to assist in holding the retainer 66 in place.
Retainer 66 is staple-shaped and is preferably formed of a
non-corroding spring stock having a width substantially greater
than its thickness. Stainless steel or rust proof steel is suitable
material for the retainer 66. There is a bowed connecting portion
67 which has a width greater than the space between walls 61 having
in-turned return portions 73 which seat on bottom 60 when the
retainer is in operative position (solid lines in FIG. 9).
Initially, the legs 74a, b of retainer 66 diverge outwardly and one
leg 74b is preferably longer than leg 74a. The longest leg 74b is
first inserted between the wall portions 61 and the shorter leg is
then forced toward the longer leg until the legs fit between the
walls 61. The upper portions 68 of each leg are elongated and, in
the assembled position of the retainer 66 in the holder 31, these
upper leg portions 68 fit around the spool 51 and forwardly of
shoulder 52 and thus prevent withdrawal of the tooth from the
holder. Beyond the upper leg portions 68 are outwardly offset leg
portions 69 which engage the outward offset walls 62 of the opening
57. To facilitate sliding of retainer 66 in and out relative to
opening 57 the ends 76 are turned inward in short 45.degree. bends.
In inward position the upper leg portions prevent withdrawal of the
tooth 32 but in retracted position with the interconnection 71
between each leg portion 68 and leg portion 69 engaging shoulders
63 (dot and dash position of FIG. 9) the shoulder 52 is free to
move forwardly so that the tooth may be removed.
To facilitate removal of the tooth, an opening 54 is formed in
holder 31 behind the back end 49 of the tooth 32 so that an
instrument may be inserted to drive the tooth out of its holder.
However, ordinarily the tooth may be manually withdrawn. Further,
the opening 54 permits egress of dirt.
In use, the retainer 66 is installed as heretofore explained and is
pulled up to retracted or dot-and-dash position as shown in FIG. 9
with the interconnection 71 abutting the shoulder 63. In this
position, the proximal end 46 of the tooth 32 may be inserted in
the recess 56. If necessary, a hammer may be used to drive the
tooth into place. When the tooth is in place, the connecting
portion 67 of retainer 66 is forced down until the return portions
67 seat against the bottom 60. In this position, the upper leg
portions 68 straddle the spool 51 and fit ahead of the shoulder 52
and prevent the tooth from being withdrawn from the holder. To
secure retainer 66 in operative position, the end 72 of the longer
leg 74b is bent outward as shown in FIG. 9 against the flared
portion 64. When it is necessary to remove the tooth, a prying tool
may be inserted under the connection portion 67, pulling the
retainer 66 from solid line to dot-and-dash line position as shown
in FIG. 9. Thereupon the tooth may be removed by hand and a new
tooth installed by hand. If needed, an instrument may be inserted
through the opening 54 to drive the tooth out if it tends to stick
in its holder. Occasionally a retainer 66 will be fractured. The
retainer is easily replaced when this occurs but in normal usage
the retainer may be used repeatedly and the tooth 32 removed for
replacement or sharpening as frequently as necessary.
Directing attention now to the structures of FIGS. 3A-C, it will be
seen that the arm 33 is relatively short and is substantially in
alignment with the link portion 34. The holder 31 has its recess 56
(best shown in FIG. 7) diverging slightly outwardly-forwardly and
the distal 36 of the tooth 32 also diverges outwardly. Hence, the
cutting edge 37 of the tooth 32 cuts a substantially vertical
sidewall 22 as shown in FIG. 2. The holder on the opposite side of
the chain is a mirror image of that shown in FIGS. 3A-C.
Directing attention now to FIGS. 4A-C, again the arm 33b is
comparatively short but longer than arm 33. The holder 31b is
offset outwardly relative to the link portion 35. Again the recess
in the holder 31b faces forwardly in the direction of movement of
the chain and is so disposed that in normal operative position the
cutting edge 37 of the tooth 32b is horizontal.
In FIGS. 5A-C, again arms 33c are relatively short and the holders
31c are offset inwardly relative to the link portions 34c. The
holders 31c are disposed at angles so that the cutting edges 37 are
at about 45.degree. angles with respect to the vertical.
The holder 31d shown in FIG. 6 is supported by an arm 33d which is
substantially longer than the arms of the previous modification. As
is shown by a comparison of FIG. 5B and FIG. 6, the cutting edge 37
of the tooth 32d is elevated above the cutting edge 37 of the tooth
32c of FIG. 5B. In other respects the structures of FIGS. 5B and 6
are the same except that there is an off-set of the holder 31d to
the right of that of 31c which results in the wall portion 26 being
set in relative to the wall portion 24.
The holder 31a shown in FIGS. 3A-C is for a relatively narrow
trench. Holder 31a of FIG. 3D is for a wider trench. Link portion
34c is the same as the corresponding portion of FIG. 3B but arm 33c
slants outward away from the center line of the chain and may be
reinforced by gusset 81. Thus holder 31c and tooth 32c are similar
but outwardly disposed relative to the corresponding elements of
FIG. 3B.
For the wider trench, holder 31f, as shown in FIG. 4D, is outwardly
disposed relative to holder 31b of FIG. 4B. Arm 33f bends outward
and is reinforced by gusset 82. The holders 31c and 31d accommodate
either the wider or narrower trench. Note in FIG. 2 that the outer
corner of tooth 32cR intersects the center line of tooth 32bR for
the narrower trench. The trench may be wider by twice the overlap
(i.e. one tooth width) by off-setting teeth 32aR and L and 32bR and
L outward. Thus, assuming teeth 32 are 2 inches in width, either a
7 or 9 inch trench may be dug merely by changing the angles of arms
33c and f relative to arms 32a and b.
It will be understood that the chain 27 moves at a relatively high
speed. There is a tendency for centrifugal force to dislodge the
retainer 66. This is overcome in accordance with the present
invention by locating the opening 57 so that the retainer 66 tends
to be forced inward relative to the opening 57 rather than being
forced outwardly. Thus, in FIG. 3A the opening 57 is transverse to
the direction of movement of the chain and centrifugal force
neither drives the retainer out nor forces it in. Similarly in FIG.
4C the retainer 66 is inserted from the underneath upwardly and the
opening 57 shown in FIG. 4C is for the leg portion 69 rather than
for the connecting portion 67. Hence, centrifugal force drives the
retainer 66 inward relative to holder 31b. Again in FIG. 5A the
opening 57 is slanted so that the retainer is driven in. Although
not shown, the members illustrated in FIG. 6 have their opening 57
located in a same manner.
In all of the locations of the openings 57 which have been
illustrated, it is clear that access to pull the connecting portion
67 of the retainers 66 to inoperative position is convenient so
that changing teeth 32 is relatively simple. Very few tools are
required to remove and replace teeth and such tools are
screwdrivers and hammers, all of which are conveniently on hand at
construction sites.
* * * * *