U.S. patent number RE32,076 [Application Number 06/619,835] was granted by the patent office on 1986-02-04 for modular screw anchor having lead point non-integral with helix plate.
This patent grant is currently assigned to A. B. Chance Company. Invention is credited to Edward Dziedzic.
United States Patent |
RE32,076 |
Dziedzic |
February 4, 1986 |
Modular screw anchor having lead point non-integral with helix
plate
Abstract
A high strength, modular screw anchor is disclosed which
exhibits enhanced failure resistance notwithstanding use of
essentially the same amount of material as conventional anchors,
and which can be installed using existing installation equipment.
The preferred screw anchors of the invention include an elongated
rod having one or more separate, specialized anchor members
supported thereon, and an improved, obliquely oriented, beveled
earth-penetrating lead to facilitate installation, particularly in
rocky soils. The anchor member includes a tubular, central,
rod-receiving hub presenting a polygonal in cross-section bore
therethrough, and an outwardly extending helical blade affixed to
and coaxial with the hub. In installation procedures the anchor rod
is passed through the hub bore and the anchor member is operably
coupled to the rod (as by resting it atop an outwardly extending
shoulder provided on the rod); the tubular shank of a standard
anchor wrench is next telescoped over the anchor rod and inserted
into the hub bore such that a driving connection is established
between the rod, shank and anchor member. Axial rotation of the
wrench thus effects corresponding rotation of the screw anchor for
installation purposes. The earth-penetrating lead of the screw
anchor may be formed integrally with the major portion of the rod,
or threaded thereon; in the latter case the overall length of the
rod can be adjusted as desired. The modular nature of the screw
anchors hereof permits stocking of only a relatively few standard
components which can be used as needed in the field to achieve a
desired anchor configuration.
Inventors: |
Dziedzic; Edward (Centralia,
MO) |
Assignee: |
A. B. Chance Company
(Centralia, MO)
|
Family
ID: |
26834714 |
Appl.
No.: |
06/619,835 |
Filed: |
June 12, 1984 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
136881 |
Apr 3, 1980 |
04334392 |
Jun 15, 1982 |
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Current U.S.
Class: |
405/303; 175/400;
405/258.1; 405/259.1; 52/157 |
Current CPC
Class: |
E02D
5/801 (20130101); E02D 2200/1671 (20130101) |
Current International
Class: |
E02D
5/80 (20060101); E02D 005/74 () |
Field of
Search: |
;405/258,259,260,261,262,232,268,269,244 ;52/157,156,155,158-162
;175/320,322,399,400 ;299/79 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
A B. Chance Co., Printed Publication..
|
Primary Examiner: Taylor; Dennis L.
Attorney, Agent or Firm: Schmidt, Johnson, Hovey &
Williams
Claims
Having thus described the invention, what is claimed as new and
desired to be secured by Letters Patent is:
1. In combination:
an elongated rod .Iadd.having earth penetrating lead means adjacent
one end thereof.Iaddend.;
and anchor member .Iadd.initially separate from said rod and
.Iaddend.including a hub presenting a bore.[.therein.].
.Iadd.extending completely through said hub.Iaddend., and an
outwardly extending, load-bearing element affixed to the exterior
of said hub,
.Iadd.said hub being slidably received on said rod such that
.Iaddend.said rod l .[.extending into.]. .Iadd.extends completely
through .Iaddend.said hub bore;
means for operably coupling said anchor member to said rod;
a wrench including an elongated, tubular shank telescoped over said
rod and extending into said hub bore such that the portion of said
shank .[.extended.]. .Iadd.which extends .Iaddend.into the hub bore
is .[.disposed between said rod and .Iadd.said
.Iaddend.hub;.]..Iadd., .Iaddend.
.[.structure for drivingly connecting said shank to both of said
rod and said anchor member such that axial rotation of said shank
effects corresponding rotation of said rod and anchor member and
distribution of driving forces from said shank to said rod and
anchor member, .[.whereby.]. .Iadd.said wrench shank having outer
wall surfaces for cooperative, driving engagement with an internal
portion of said hub defining at least a part of said bore,
said wrench shank having inner wall surfaces,
said rod having structure for complemental, mating fit with said
inner wall surfaces of said wrench shank such that said wrench, in
disposition over said rod and within the hub bore of said anchor
member, is operable to prohibit free lateral play of said rod
relative to said anchor member and establish a connection of
sufficient strength to enable driving rotation of said anchor
member as well as independent, driving rotation of said rod lead
means under forces such that .Iaddend.installation of the rod and
anchor member into the earth is facilitated without .Iadd.collapse
of said wrench shank or .Iaddend.breakage .[.thereof; and means
defining an earth-penetrating lead adjacent one end of said rod.].
.Iadd.of said rod or anchor member.Iaddend..
2. The combination as set forth in claim 1, said hub being defined
by an elongated, tubular member.
3. The combination as set forth in claim 1 said hub being defined
by a pair of elongated, opposed, metallic angles cooperatively
defining said bore therebetween.
4. The combination as set forth in claim 1, said hub having one end
thereof of lesser diameter than the remainder of the hub.
5. The combination as set forth in claim 1, said load-bearing
element comprising a helical blade.
6. The combination as set forth in claim 1 wherein said coupling
means comprises engagement structure on one of said hub or rod for
supporting said anchor member.
7. The combination as set forth in claim 6 wherein said engagement
structure comprises outwardly extending shoulder means on said rod.
.[.8. The combination as set forth in claim 1 wherein said
connecting structure comprises cooperative mating fit wall surfaces
on said wrench shank, rod,
and hub respectively..]. 9. The combination as set forth in claim
1, wherein said internal portion of said hub defining said bore
includes walls at least in part defining said hub bore and
presenting a section thereof of polygonal cross-section, said
wrench shank being of
non-circular cross-section for operatively engaging said walls. 10.
The combination as set forth in claim 1 wherein said
.[.lead-defining.].
.Iadd.lead .Iaddend.means comprises an elongated terminal section.
11. The combination as set forth in claim 10, said terminal section
being oriented
at an angle relative to the major portion of said rod. 12. The
combination as set forth in claim 10 wherein said terminal section
is threadably
coupled to said major portion of said rod. 13. The combination as
set forth in claim 10, said terminal rod section being provided
with an elongated, threaded bore therethrough, said rod being
threaded for reception in said bore for adjustment of the overall
length of the entire rod, including said terminal section. .[.14.
The combination as set forth in claim 1 wherein said lead-defining
means comprises at least one earth penetrating portion connected to
said hub..]. .[.15. The combination as set forth in claim 1, said
anchor member being free of permanent connection to said rod,
whereby said combination is modular in nature..].
6. In a method of driving an anchor into the earth wherein the
anchor includes an elongated rod .Iadd.having lead means
.Iaddend.and an outwardly extending load-bearing element operably
coupled to the rod, and wherein the method includes the steps of
telescoping an elongated, tubular wrench shank over said rod,
drivingly connecting said wrench shank and rod, and axially
rotating said shank to effect corresponding rotation of the rod and
element to install said anchor into the earth, the improved method
which comprises:
providing an anchor member having an open-ended hub presenting a
bore therethrough, with said element affixed to the exterior of the
hub;
passing said rod .Iadd.completely .Iaddend.through said hub and
operably coupling said anchor member to the rod;
telescoping said wrench shank over said rod, .Iadd.and
.Iaddend.inserting the end of said shank into said hub bore such
that said shank end is disposed between said rod and hub.[., and
drivingly engaging said connecting said shank, rod and anchor
member.]. .Iadd.and to prohibit free lateral play of said rod
relative to said anchor member and for establishment of a
connection of sufficient strength to enable driving rotation of
said anchor member as well as independent, driving rotation of said
rod lead means.Iaddend.; and
axially rotating said wrench shank to effect distribution of
rotative driving forces from the shank .Iadd.directly and
independently .Iaddend.to said rod and .Iadd.also directly and
independently to said .Iaddend.anchor member.Iadd., .Iaddend.and
.[.corresponding rotation of.]. .Iadd.to correspondingly rotate
.Iaddend.said rod and anchor member .Iadd.such that installation of
said rod and anchor member into the earth is facilitated without
collapse of said wrench shank or breakage of said rod or anchor
member. .Iaddend. 17. An earth anchor, comprising:
an elongated rod having an earth-penetrating lead .Iadd.means
.Iaddend.adjacent one end thereof, and outwardly extending,
polygonal shoulder-defining structure proximal to said lead;
an anchor member including an open-ended hub having interior walls
defining a bore therethrough extending between said open ends, and
an outwardly extending load-bearing member secured to said hub,
.Iadd.said hub being slidably received on said rod .[.passing.].
.Iadd.extends completely .Iaddend.through said hub bore, with
portions of said bore-defining walls surrounding said
shoulder-defining structure being in spaced relationship from said
structure and cooperatively defining a polygonal
structure-receiving opening; and
means operably coupling said anchor member to said rod,
the cross-sectional dimensions of said bore, and the spacing
between said shoulder-defining structure and said wall portions,
being sufficient for passage of a complemental wrench tube between
said interior walls and said rod, and between said wall portions
and said shoulder-defining structure.[., for establishing a driving
engagement and connection between said tube, shoulder-defining
structure and opening-defining wall portions, whereby axial
rotation of the tube distributes rotative driving forces from the
tube to the rod and anchor member and effects corresponding
rotation in unison to said rod and anchor member, in order to
facilitate installation of the anchor into the earth without anchor
breakage.]. .Iadd.to prohibit lateral free play of said rod
relative to said anchor member and to establish a connection of
sufficient strength to enable driving rotation of said anchor
member as well as driving rotation of said rod lead means under
forces such that installation of the rod and anchor member into the
earth is facilitated without collapse of said wrench shank
or breakage of said rod or anchor member.Iaddend.. 18. The earth
anchor as set forth in claim 17, said hub bore being polygonal and
of substantially constant cross-sectional dimensions throughout the
length thereof between
said open ends. 19. An anchor rod, comprising:
an elongated rod presenting an upper end and an opposed lower
end;
a radially outwardly extending flange adjacent the lower end of
said rod.Iadd., said flange being engageable with an anchor member
having an outwardly extending load bearing member.Iaddend.;
an elongated earth-penetrating lead below said flange, the
longitudinal axis of said lead being disposed at an angle relative
to the longitudinal axis of said rod; and
radially outwardly extending, polygonal shoulder-defining structure
above said flange and proximal thereto, said flange extending
radially outwardly from said rod farther than said
shoulder-defining structure,
said lead serving to cut through the earth during rotative
installation of the rod to facilitate installation thereof,
particularly in densse or rocky soils.Iadd.,
said shoulder-defining structure being engageable with internal
walls of a tubular wrench shank for a cooperative, mating fit
connection such that as said shank is rotated, the rotative forces
are evenly distributed to said rod without breakage
thereof.Iaddend.. .Iadd.20. The combination as set forth in claim
1, said rod being of integral construction. .Iaddend. .Iadd.21. The
combination as set forth in claim 1, said rod being formed of
separable components threadably coupled together. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is concerned with an improved, modular screw
anchor (and a method of installing the same) which is characterized
by extremely high resistance to breakage, particularly during
installation when the anchor is subjected to high torsional
loadings. More particularly, it is concerned with such modular
screw anchors having separate rod and anchor members and which are
designed to be installed using conventional, existing screw anchor
wrenches and the like. A prime feature of the anchors in accordance
with the invention is that greatly improved resistance to breakage
is obtained despite the fact that the quantity of metal used in
fabrication of the anchors is essentially the same as that of prior
units having significantly lower resistance to breakage.
2. Description of the Prior Art
Present day earth screw anchors used by utilities and others for
guying purposes generally comprise an elongated, solid, square in
cross-section shaft having one or more helical, outwardly
extending, load-bearing blades welded thereto, and an elongated,
upwardly extending anchor rod threadably coupled to the anchor
shaft. In installation procedures, an elongated anchor wrench
including a tubular shank is telescoped over the anchor rod and
drivingly engages the anchor shaft at the region of the helical
blade or blades. Such engagement is established by virtue of a
mating fit between the square cross-section of the shaft, and the
corresponding square tubular configuration of the wrench shank.
Installation of the anchor is accomplished by powered rotation of
the wrench which in turn effects corresponding rotation of the
anchor shaft and blade, so that the anchor is screwed into the
earth. This is continued until the blade reaches sub-soil having a
density sufficient for holding purposes.
Although conventional anchors and installation methods are well
established, a number of problems remain. One of the most serious
difficulties of relatively recent origin stems from the fact that
the torque capacity of modernday installation equipment
significantly exceeds the maximum torsional strengths of standard
anchors. That is to say, newer installation equipment will commonly
have a torque capacity in the range of ten thousand foot-pounds or
more, whereas standard anchors have rated strengths in the range of
four to seven thousand foot-pounds. As a result, utilities have
experienced anchor breakage during installation, particularly in
hard, dense, rocky soils. The principal breakage mode is that of
anchor shaft breakage under torsional load when the helix strikes
an obstruction. In other cases the helix may be stripped from the
shaft, or the anchor wrench may split and simply rotate relative to
the earth anchor.
One possible solution to these problems is to simply use thicker
and stronger metal components in the anchor shaft and helix.
However, this alternative is not a practical solution because of
the cost involved and more importantly because it would necessitate
the purchase of new anchor wrenches and related equipment.
Obviously, utilities are loathe to simply scrap their expensive
installation equipment if another solution is available.
Accordingly, attempts have been made to strengthen conventionally
sized earth anchors by improving material quality (e.g., by using
special steel alloys having enhanced torque strength) and/or heat
treating the central anchor shafts. However, these efforts have
achieved only limited success, and are also relatively (twice or
more) expensive.
Another fact of present anchors is the loss in strength which is
inherent in the factory welding of the helix to the central shaft.
This weld loss typically ranges from a few percent to as high as 10
to 15% and is directly subtractive from the strength of the central
shaft. This can lead to field breakage during installation attempts
by utilities and is a source of increased costs and constant
concern on the part of the user. For the reliability required in
utility electric distribution lines, the user must be confident
that the anchor as installed will be undamaged after it has been
subjected to installation torques. With present systems the user is
forced to select the product torques just adequate for installation
because of product costs and the wrench system in use, and this
increases the risk of undetected damage to the anchor during
installation.
Another limitation of present screw anchors is that when a strong
anchor installation is desired in a particular soil, the maximum
rod size, which must always be smaller in cross-section than the
anchor shaft, limits the load holding capacity. This is true
because the only practical way to attach the anchor rod to the
anchor shaft is by drilling and tapping the shaft. The threaded
connection zone thus becomes the holding power limit. Present
maximums are about 36,000 lbs., obtained with a 1" rod.
Yet another problem associated with conventional anchors stems from
the integral welded construction of the shaft-helix combination.
Because of this, users are required to stock a wide variety of
anchor sizes and types ( e.g., single or multiplex helix units) to
meet the varying demands encountered in the field. As such,
problems or ordering, warehousing and cost are multiplied.
SUMMARY OF THE INVENTION
The problems described above are in large measure solved by the
present invention. Broadly, the earth anchors of the invention
include an elongated rod along with an anchor member operatively
coupled thereto in the form of a central, open-ended, rod-receiving
hub having a bore therethrough and an outwardly extending
load-bearing element (such as a helical blade) thereon. Means such
as an upset shoulder on the rod is provided for supporting the
anchor member. The hub bore is advantageously polygonal in
cross-section and is sized for receiving a standard wrench shank
therewithin such that the shank is drivingly connected to the
central rod and anchor member. Disposition of the wrench within the
hub decreases the possibility of wrench breakage, inasmuch as any
such breakage would necessitate a severe external compression of
the tubular shank.
Further, because of the fact that the anchor helix is secured to a
hub spaced a significant distance from the central rod, the torque
lever arm is much longer and weld length is substantially
increased; this permits a smaller fillet weld to reduce the
strength loss effect, and increases the shear resistance of the
welded helix as compared with conventional units. This hub design
thus overcomes for the most part the weld strength loss problem of
the usual anchors.
The anchor members of the present invention are constructed using
essentially the same quantity of metal (or less) as prior units of
the same general class, even though tubular hubs are employed as
opposed to solid shafts. The significance of this fact becomes
plain when it is considered that mill prices for large quantities
of steel either in solid bars or square structural tubes are
essentially the same on a per pound basis; thus material costs are
not increased with the anchors of the invention over standard solid
shaft designs.
Use of tubular hubs for the anchor members hereof also greatly
enhances the torsional strength of the unit, as opposed to solid
bars. This stems from the demonstrable fact that the maximum shear
resistance of a hollow tubular member is greater than that of a
solid cylindrical shaft, where the net cross-sectional area of
material is the same in both cases.
The modular nature of the anchors of the invention allows a user to
custom design a given anchor in the field to meet various
conditions. For example, if a multiple helix is required, a pair of
anchor members can be placed on a central rod, using a tubular
spacer between the respective hubs. Thus, only a relatively few
standard components need be purchased and stored as compared with
present practices.
In short, the anchors of the present invention give a number of
significant advantages from the standpoint of strength and
flexibility of use, without increases in material costs and while
permitting use of standard installation equipment.
A wide number of specific anchor configurations are possible. For
example, the anchor member hubs may be generally square in
cross-section, or have a circular body with a swaged wrench
shank-engaging portion. The hubs may further be unitary, formed of
separate pieces (such as opposed metallic angles), or fabricated
from plate.
An improved anchor lead is also provided to facilitate installation
into dense or rock-like soils. The lead includes an elongated
section oriented at an angle relative to the longitudinal axis of
the remainder of the rod. The lower end of the section is
preferably beveled and presents an earth-cutting lower edge. The
offset section effectively cuts through the earth during
installation to assist in proper anchor placement.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view illustrating the installation of a screw anchor in
accordance with the invention, using a powered digger for this
purpose;
FIG. 2 is a fragmentary, somewhat exploded view illustrating the
components of a screw anchor in accordance with the invention, a
conventional screw anchor wrench, and the end of a kelly bar used
in installation procedures;
FIG. 3 is an enlarged, fragmentary vertical sectional view
illustrating a modular screw anchor in accordance with the
invention, with the tubular shank of a standard screw anchor wrench
drivingly connected to the screw anchor;
FIG. 4 is a fragmentary view depicting the shouldered,
earth-penetrating end of a screw anchor rod in accordance with the
invention;
FIG. 5 is a sectional view taken along line 5--5 of FIG. 4;
FIG. 6 is a bottom view of the earth-penetrating end of the rod
illustrated in FIGS. 4 and 5;
FIG. 7 is a fragmentary elevational view of an overall earth anchor
rod;
FIG. 8 is an elevational view similar to that of FIG. 7 and
depicting, with parts broken away for clarity, a shouldered earth
anchor rod having a pair of anchor members disposed thereon and
with a tubular spacer between the respective anchor members;
FIG. 9 is a view similar to that of FIG. 7 but illustrates another
embodiment of the invention wherein an earth-penetrating lead
section is threaded onto the end of a correspondingly threaded rod
so as to cooperatively present a complete earth anchor rod;
FIG. 10 is a vertical sectional view of the threadably mounted,
earth-penetrating lead illustrated in FIG. 9;
FIG. 11 is a plan view of the anchor member in accordance with the
invention, wherein the central hub thereof is cooperatively defined
by a pair of elongated, metallic angles;
FIG. 12 is an elevational view of the anchor member depicted in
FIG. 11;
FIG. 13 is a plan view of another type of anchor member in
accordance with the invention;
FIG. 14 is an elevational view of the structure illustrated in FIG.
13;
FIG. 15 is a plan view of another type of anchor member in
accordance with the invention;
FIG. 16 is an elevational view of the anchor member of FIG. 15;
FIG. 17 is a plan view of yet another type of anchor member within
the ambit of the invention;
FIG. 18 is a side elevational view of the anchor member of FIG.
17;
FIG. 19 is a fragmentary elevational view of another earth anchor
of the invention, wherein depending portions of the anchor member
hub cooperatively define the earth-penetrating lead for the
anchor;
FIG. 20 is a vertical sectional view taken along line 20--20 of
FIG. 19; and
FIG. 21 is a view similar to that of FIG. 19, but illustrates the
use of a second anchor member disposed atop the lowermost member
and presenting a second load-bearing blade.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, and particularly FIGS. 2-7, one type
of screw anchor 10 in accordance with the invention is illustrated.
Broadly speaking, the anchor 10 includes an elongated rod 12 made
up of a major portion 14 and an earth-penetrating lead 16, and a
modular one-piece anchor member 18 disposed on and operatively
coupled to the rod 12.
In more detail, the rod 12 in the embodiment illustrated is an
integral member having an elongated, rectilinear, major portion 14
of cylindrical cross-section (see FIG. 5), along with a
wrench-engaging portion 20 of generally square cross-section at the
lowermost end of the portion 14, and an upper threaded end 15 (see
FIG. 7). An outwardly extending, circular shoulder 22 is provided
adjacent the lower end of the portion 20 for purposes to be
explained. On the other hand, lead 16 is in the form of an
elongated, generally square section 24 which is obliquely oriented
relative to the longitudinal axis of major portion 14. As can be
seen, this section 24 extends and depends from the shoulder 22, is
beveled as at 25 at its lower end, and presents a lowermost
earth-cutting edge 25a.
Anchor member 18 includes an elongated, open-ended hub 26 of
generally square cross-section and presenting a similarly
configured bore 28 therethrough. An outwardly extending,
load-bearing helical blade 30 is affixed (as by welding) to the
exterior of the hub 26. As best seen in FIGS. 2 and 3, the hub 26
receives the rod 12, as well as the wrench-engaging portion 20.
Moreover, the cross-sectional dimensions of the rod are
substantially smaller than the dimensions of the surrounding hub
bore 28, and the purpose of this will be explained hereinafter.
The installation of screw anchor 10 into the earth is illustrated
in FIGS. 1-3. More specifically, the anchor 10 is designed for
installation using standard. existing equipment such as digger 32
and anchor wrench 34. The powered digger 32 includes the usual boom
36 equipped with a hydraulic motor 38. A drive shaft in the form of
a kelly bar 40 is coupled to the output of motor 38, and is
received within an adaptor 42. The adaptor 42 is in turn coupled to
the upper end of wrench 34. The installation wrench 34 is of the
type described in U.S. Pat. No. 3,377,077 (the latter patent being
incorporated by reference herein) and includes a pair of elongated,
shiftable dogs 44 and a tubular, depending, square in cross-section
shank 46.
In installation procedures, the anchor member 18 is first slipped
over rod 12 and passed down the length thereof until the underside
of hub 26 engages shoulder 22 (see FIG. 3). At this point the shank
46 of wrench 34 is telescoped over rod 12 and into the bore 28 of
hub 26. Finally, the lowermost end of the shank 46 is lodged
between the surfaces presented by wrench-engaging portion 20 of rod
12, and the surrounding surfaces defining the bore 28. This
establishes a mating fit driving connection between the shank 46,
rod 12 and anchor member 18. Means such as a simple set screw
installed in the wrench tube wall above the upper margin of hub 26,
prevents the anchor from sliding up the wrench during installation
(see FIG. 3). Installation of the anchor is accomplished by axial
rotation of shank 46 through the medium of motor 38 and associated
drive described above, which effects corresponding axial rotation
of rod 12 and anchor member 30. When the anchor has been installed
to a desired depth (using extensions of anchor rod and wrench tube
if necessary), the wrench is withdrawn by pulling the same upwardly
and thereby leaving the anchor 10 installed in place. This
installed anchor is then ready for installation of a guy or the
like thereto.
The concepts of the present invention permit a wide variety of
variations in specific anchor configurations. For example, (see
FIG. 8 ) a pair of anchor members 18 can be installed upon a rod 12
and spaced a desired distance through use of simple tubular spacer
48. In practice, a first anchor member is slipped onto rod 12 as
explained above, and passed down the length thereof until shoulder
22 is encountered. Tubular spacer 48 is next telescoped over the
rod 12, followed by the second anchor member. Installation of this
modified form of the invention proceeds exactly as described
above.
FIGS. 9-10 illustrate an alternate anchor rod 50. In this instance
the rod 50 includes an elongated, cylindrical major portion 52
having a threaded lower end 54, a threaded upper end 56, and a nut
58 applied to the latter. In this case however a bored
earth-penetrating lead 60 is provided which includes an upper,
generally square in cross-section wrench-engaging portion 62, an
outwardly extending, circular shoulder 64, and a depending,
elongated lead section 66. As best shown in FIG. 10, an elongated,
threaded bore 68 extends vertically through the entirety of the
lead 60; moreover, the longitudinal axis of section 66 is obliquely
oriented relative to the longitudinal axis of major portion 52, and
relative to the axis of bore 68. The lowermost end of the section
66 is beveled as at 70, and presents an earth cutting edge 72. Rod
50 is assembled simply by threading the lead 60 onto the lower end
54 of major portion 52. As depicted in FIG. 9, such threading can
be such that the extreme lower end of the threaded section extends
below the obliquely oriented lead section 66. In this way the
overall effective length of the anchor rod 50 can be adjusted.
Therefore, the problems heretofore encountered in providing precise
lengths for anchor rods can be easily overcome.
Three additional embodiments are shown in FIGS. 11-18, inclusive.
In each of these three embodiments an anchor member in accordance
with the invention is illustrated, and in each case a single
helical blade attached to a central hub is depicted. In the three
embodiments however, various types of central hubs are illustrated.
Installation of anchors using the anchor members of the three
embodiments proceeds exactly as outlined above.
FIGS. 11-12 depict an anchor member 74 having a helical,
load-bearing blade 76 and a central hub 78. In this instance the
hub is formed from a pair of elongated, opposed, metallic channels
80, 82 which cooperatively present an elongated, open-ended central
bore 84 therebetween of generally square cross-section. In this
instance the welding of the blade 76 to the opposed channels 80, 82
serves to integrate the overall anchor member 74 as a one-piece
unit.
FIGS. 13-14 illustrate an anchor member 84 having a blade 86 and a
central hub 88. In this case the hub includes a circular in
cross-section upper tubular portion 90, along with a swaged,
restricted lower portion 92 presenting a square in cross-section
lower bore 94. In the use of the anchor member 84, the wrench tube
46 is passed downwardly through upper portion 90 and into
engagement with the inner walls defining the lower bore 94.
FIGS. 15-16 show another anchor member 96 having a blade 98 and hub
100. Here again, the hub includes a circular in cross-section upper
portion 102, and a swaged lower portion 104 presenting an octagonal
in cross-section lower bore 106. Referring to FIG. 15, insertion of
a standard square in cross-section wrench tube 46 into lower bore
106 is illustrated. As can be seen, a mating fit between the walls
of the wrench shank, and the walls defining lower bore 106,
establishes a driving connection.
Finally, FIGS. 17-18 depict an anchor member 108 having a helical
blade 110 and a central hub 112. In this instance the hub is formed
from a unitary blade 114 of material which is bent in a spiral-like
form to define a generally square in cross-section, open-ended bore
116 therethrough.
FIGS. 19-21 illustrate another type of anchor in accordance with
the invention. Specifically, this anchor 118 includes an elongated,
threaded rod 120 provided with an adjustable nut 122 adjacent the
lower end thereof. An anchor member 124 is also provided which
includes an open-ended, square tubular section 126 having a helical
blade 128 welded to the exterior thereof. The section defines an
elongated bore 130 along the length thereof, and is provided with
annular, inwardly extending, nut-engaging element 132 which is
rigidly affixed to tubular section 126, and which engages nut 122
for supporting the anchor member 124 on rod 120. The hub 126
further includes a pair of laterally spaced, side-by-side,
depending pointed projections 134 which extend below the element
132 and in effect define an earth-penetrating lead for the anchor
member 118.
In FIG. 21 a double helix form is depicted which includes, in
addition to rod 120 and anchor member 124, a second anchor member
136. The member 136 includes a square tubular hub 138 of length
greater than that of section 126 with a helix 140 welded to the
exterior thereof.
In the use of the FIGS. 19-21 embodiment a standard wrench tube is
passed through the section 126 until element 132 is reached. This
drivingly couples the wrench tube and the section 126 (in the case
of FIG. 21, the anchor member 136 would be similarly coupled). The
projections 134 define the earth-penetrating lead for the
anchor.
Actual field testing of anchors in accordance with the invention
has confirmed that anchors are very resistant to load-induced
breakage. As pointed out above, this increase in strength is
obtained without use of additional material as compared with
conventional anchors, and further the anchors hereof can be
installed using existing wrenches and the like. Moreover, the
modular nature of the present anchors reduces storage requirements
and allows purchase of fewer components to meet various anchoring
needs.
The modular construction of the anchors of the invention also
allows substantial strengthening of the rod-lead connection. In
prior anchors the outer diameter of the anchor shaft was limited
because of the need to fit within a wrench tube, and accordingly
the outer diameter of the tension rod connected thereto was
correspondingly limited. In the present invention however, sizing
constraints on these components are much less, so that a larger and
stronger tension rod can be employed (particularly at the region of
the lead connection), and this increases the holding capability of
the overall anchor. Further, the relative lack of size constraints
on the anchor members hereof makes it possible to use synthetic
resin materials in the fabrication thereof as opposed to metal.
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