HK1126831B - Improved earth anchor - Google Patents

Description

Improved ground anchor

RELATED APPLICATIONS

The invention requires application number No. submitted in 2006, 12, 19 and: 29/270,187 priority of co-pending appearance design.

Technical Field

The present invention relates to earth anchors and more particularly to rotary earth anchors.

Background

Rotating or tilting earth anchors or root canals (earth anchors) are well known and generally comprise: a main body portion having a leading edge adapted to be pressed into the ground, a trailing edge including an outturned lip and a cable or cable connection point located between the leading edge and the trailing edge, the cable or cable connection point being located generally at a point intermediate or toward the trailing edge of the overall length of the anchor, such that when a force is applied to the cable or connected cable after the anchor is inserted into the ground, the outturned lip of the trailing edge will bite into the ground, causing the anchor to rotate or pivot to a locked position at substantially right angles to the pull-out force. Such anchors include disc anchors (planeanchorages) as disclosed in us patent 3,969,854, which are often difficult to drive into the ground. More recently such anchors have been replaced by cylindrical or tubular anchors having a bore in the body into which the drive rod can be inserted from the trailing edge to a rod attachment point at or adjacent the bottom or end of the bore. Such anchors, as shown in U.S. patent 4,044,513, use an everted lip at the trailing edge which substantially defines an opening to the interior. Such anchors are also disclosed in U.S. patent 4,096,673, which is assigned to the assignee of the present invention. Anchors of this type have been sold by the assignee Foresight industries inc. under the trademark Duckbill, and generally consist of a cast cylinder having a cruciform leading edge, a trailing edge with an everting lip, a blind hole, a raised rib at the top remote from the everting lip, the raised rib also having an opening therethrough for receiving a hook, cable or other loading device to initiate rotation or "load lock" of the anchor, i.e., securing, after driving the anchor into the ground by a drive rod using a hammer, jackhammer, hydraulic device or other similar device. A variation of the basic shape of such an anchor is shown in US5,775,037, in which the body may be provided with sides which extend outwardly to the central aperture, beyond the side edges of the raised ribs. Another variation is shown in U.S. patent 4,802,317, assigned to the present assignee, which uses a widely used shoulder extending laterally from a cylindrical central body portion that includes a blind bore. These wings may have a sharp leading edge and allow the wings to increase the contact area of the anchor with the ground when the anchor is rotated to the locked position, thereby providing a wider surface to resist the pull-back force of the anchor. Such ground anchors are sometimes referred to as wing anchors. However, the presence of such wings has drawbacks in certain situations: (a) during insertion of the anchors, they provide a much larger area to be driven into the ground, and therefore require a greater driving force; and (b) the force required to pivot and lock the anchors also increases significantly due to their considerable lateral extension relative to the central body. In addition, (c) the wing causes the anchor to deflect during driving. Engagement of the outer extension of the wing with another drive resisting mechanism, such as with a hard earth structure such as hard clay or with stone or rock, can affect the effect of the anchor on pivoting the anchor as it is driven into the ground, which can change the orientation of the anchor as it is driven into the ground. This can lead not only to incorrect positioning of the anchor, but also to bending of the drive rod, which in extreme cases can prevent or hinder withdrawal of the drive rod when the anchor is placed.

One method of increasing the straight line driving capability and reducing the driving force required of a wing anchor is shown in U.S. patent 6,237,289 in which the wing leading edge is provided with a set of spaced chiseled leading edges which are stepped rearwardly axially one by one and extend radially a short distance to provide the leading edge of the wing, with the leading edges of the set being longitudinally offset from each other and radially offset apart relative to the main body. Although these serrated or stepped leading edges of large wing anchors are an improvement over existing large wing anchors, the need for higher driving forces and difficulty in rotating to the locking point remain problems. Such anchors are therefore used primarily only where high load resistance is required, and more cylindrical anchors are used where low load resistance levels are expected.

However, the use of a cylindrical anchor with a cruciform drive edge risks the anchor being displaced or deviated from a straight path when driven. Because such anchors are typically driven into the ground at an angle to the vertical, which represents the angle of loading after the anchor is set, and because loading is typically not 90 degrees, particularly when the anchor is used for anchoring cables, fences, tree supports, etc., it is sometimes difficult for the anchor to be driven straight. Substantially cylindrical anchors generally have a poorer ability to grip or bear loads than similarly sized wing anchors, but are easier to drive and rotate into a locked position.

It would therefore be an advance in the art if a substantially cylindrical ground anchor could be provided with reduced driving resistance, better straight path driving tendencies, and improved load bearing capabilities.

Disclosure of Invention

The present invention achieves the above advantages by using a substantially cylindrical anchor having: a main body portion provided with raised ribs extending from the upper surface area of the cylinder, a first flat plate-like extension projecting from the front of the main body terminating in a stepped leading edge, a second substantially flat extension extending from the front of the main body and projecting generally to a leading edge plate providing a guide surface, the second plate terminating at the leading end of a set of stepped leading edges. The outermost stepped leading edge on each side of the main body extends beyond the diameter of the main body and forms the leading edge of a tapered rib which extends along the length of the main body from the leading edge of the rib to the trailing edge of the main body and which extends from the outer diameter of the main body by a width generally no greater than the width of the leading edge which is substantially the same as the leading edge of each step of the leading edge of the guide surface.

In an embodiment of the invention, the anchor comprises: a tubular or cylindrical body having a substantially conical leading or front end and a trailing edge forming an obtuse angle with the body axis and having an everting lip at the bottom of the trailing edge; a raised rib projecting above the body portion and having a connector for connecting a tension member; a blind bore extending into the body from the trailing edge; a flat leading edge member projecting forwardly from the body and carried and terminating in a chisel point; a guide plate projecting from the front of the body and laterally from the leading edge, the guide plate having a serrated or stepped leading edge on either side of the leading edge member.

In an embodiment of the invention, the anchor comprises: a substantially tubular body having a substantially sharp or inclined leading or forward end and a trailing edge at an obtuse angle to the body axis and having an everting lip at the bottom of the trailing edge; a raised rib projecting above the body portion and having a connector for connecting a traction member; a blind bore extending into the body from the trailing edge; a leading edge member projecting forwardly from the body and terminating in a chisel point; a guide plate protruding from the front of the body and laterally on each side of the leading edge, and having a serrated or stepped leading edge; the projecting leading edge is formed as a substantially flat plate extending in vertical alignment along the axis of the main body and terminating in the front of the stepped chisel edge, the guide plates terminating in their outermost edges in ribs extending along the exterior of the main body to the trailing edge, the ribs projecting from the main body approximately the width of one of the stepped leading edges of the guide surface.

It is therefore an object of the present invention to provide an earth anchor having improved driving performance, requiring minimal driving force, and having an improved straight path driving tendency.

It is another object of the present invention to provide a rotary type earth anchor of substantially cylindrical or tubular shape which provides improved driving performance by projecting surfaces extending at an angle to each other in front of the body of the anchor, as measured from the front end of the body, the protruding surface protrudes forward of the body of the anchor by a distance of 20-40% of the overall length of the anchor, or the distance of the protrusion, as measured from the transition region between the distal end of the body portion and the protrusion surface, is 10-20% of the total length of the anchor, the transition zone consists of an axially gradual diameter reduction from the outer diameter of the main body to the protruding surface, and the projecting surface terminates at a leading edge that is sharp or chiseled and includes a plurality of leading edge segments that are axially and radially offset from one another in a step-wise fashion, the projecting surface has substantially flat opposite side surfaces which resist rotation of the anchor about its axis as it is driven.

It is a further object of the present invention to provide a substantially cylindrical, elliptical or rectangular body ground anchor having a leading edge defined by chiseled surfaces formed at the leading edge of substantially flat plates spaced axially and radially from each other and projecting forwardly of the body, the plates being disposed at an angle to each other, and the body having ribs extending substantially the length of the body on opposite sides thereof, the ribs having non-blunt leading edges and generally having a width measured outwardly from the surface of the body of 20% or less of the transverse width of the body, whereby the ribs function to facilitate straight driving of the anchor without providing significant resistance or resistance to rotation.

It is a further and important object of the present invention to provide a generally cylindrical anchor having a flat plate-like extension extending forwardly of the main body portion terminating in a leading edge having a stepped rearwardly chiseled edge, the outermost chiseled edges on each side of the main body forming the leading edge of a side rib extending along the main body to the rear edge of the main body.

These and other objects that will be apparent to those skilled in the art from the description of the preferred embodiment are to be understood as being merely one embodiment of the invention, and that numerous variations in shape and size are possible within the scope of the invention.

Drawings

Figure 1 is a side view of the anchor of the present invention.

Fig. 2 is a top view of the anchor of fig. 1.

Fig. 3 is a front elevational view of the anchor of the present invention.

Fig. 4 is a side view of the other side of the anchor of fig. 1.

Fig. 5 is a bottom view of the anchor.

FIG. 6 is an elevation view of the trailing edge.

Detailed Description

As shown in fig. 1 and 2, the anchor 10 of the present invention is comprised of a substantially cylindrical body portion 11, which body portion 11 may have a generally conical forward end 12 and a rearward end 13 that forms an oblique angle with the longitudinal axis of the body. The rear end 13 incorporates an outwardly turned lip 16 at the bottom 15 of the body 11 which will bite into the soil surrounding the anchor when driven to a predetermined depth and a pull-out load is applied. The rib 17 is formed on the top 18 of the body 11 and, in the embodiment shown, comprises a protruding central section 20 protruding further from the top 18 of any part of the body, which section 20 is provided with an opening 21 extending transversely therethrough.

The opening may allow the cable to be threaded through and secured back on itself (clamp back on itself) or may provide a hook securing point so that a cable or rod may be attached to the hook. Many other examples of fastening for attaching anchor lines or rods to the raised ribs are known and can be substituted for the holes 21. These include a T-shaped slot that can receive a T-shaped head on the anchor rod, or an opening that extends entirely along the anchor from the top surface 18 to the bottom surface 15, the opening being smaller in the region of the rib than the opening at the bottom so that a rod with a head can be moved through the anchor from the bottom, the rod extending outwardly from the rib, the head pivoting at the opening and being secured therein by a smaller opening at the top of the rib. These are all conventional design means and are well known in the art.

Similarly, the tapered body portion forward end may be formed as a flat bevel, a steep end face, or other shape. The inclined or sloping wall, whether formed as part of a cone or part of a flat triangular segment having a surface at an angle to the longitudinal axis, is beneficial when the anchor is driven into the ground, as compared to a blunt radial surface, because such a surface pushes the soil behind the body away from the body 11.

Similarly, the leading top surface 30 of the raised rib 17 is preferably formed at an angle to the longitudinal axis and extends at its leading end 32 from the outer diameter surface of the main body portion to the central section 20 at an angle of attack (angle) to facilitate soil movement. As shown, the present embodiment provides a flat top surface 31 that increases in width from the intersection with the top front end 32 of the surface 18 of the main body portion at the beginning of the conical section 12, the increase in width extending rearwardly to a point forward of the section 20. The width of the segment 20 transverse to the longitudinal centre line of the main body portion is small so as to produce a sharp reduction in width at 34 between the leading portion of the rib and the connecting portion 20. The side walls 35 of the ribs extending from the flat top 31 may extend linearly outward or, as shown in the embodiment, in a more circular manner, the shape of these surfaces being a conventional design means.

Although an anchor having a flat surface 31 on the leading face of the rib has been described, it will be appreciated that an angled face (edge surface) rising to the central tip and extending all the way back from the leading point 50 of the anchor to the segment 20 is desirable to facilitate penetration of the anchor into the soil.

However, because resistance is caused by cables, hooks, rods, etc. that may extend out the sides of the rib section 20, it is desirable that the leading edge of the raised rib be positioned to guide the soil away from the section 20 to facilitate entry of the anchor into the ground.

Because the rib projects from the body portion and it provides an anchor point for the cable, rod or the like which will be under tension as the anchor pivots and as it provides the anchoring function, the rib must be strong enough to withstand such loading forces without separating from the rest of the anchor. Finally, such ribs are relatively large and are a factor in the tendency of the anchor to deviate from a straight path when driven into the ground. A blind bore 60 extends into the body from the trailing edge and terminates at a drive face 61 at or adjacent the end of the blind bore. The end may be square as shown or rounded to prevent the drive steel from quickly pointing. An elongated drive steel is inserted into the blind bore 60 and is used to drive the anchor into the ground by a force application tool, which may range from a hand held hammer to heavy equipment like a pile driver, depending on the size of the anchor. Since the depth to which the anchor is inserted into the ground depends on the size of the anchor, the load to be maintained, the soil quality, etc., the drive steel may be constructed in long, multi-part threaded connections and may not be structurally sufficient to ensure straight-line driving of the anchor itself.

While it is known to provide a cross-projection extending from the forward end of the body to facilitate penetration of the substantially cylindrical rotating anchor through the soil, such extension has not proven entirely satisfactory at preventing drift or non-linear movement of the anchor during driving. Wing anchors having relatively large wings, cross chisel shaped protruding edges and sharp wing edges projecting from the central body have been used as shown in us patent 5,031,370. Furthermore, such anchors have been provided with a serrated or stepped leading edge both in the top to bottom vertical direction and in the left to right, wing to wing horizontal direction. While these leading edges have advantages in wing anchors, they have not been used on substantially cylindrical or ellipsoidal wingless anchors.

The present invention provides front panels 70, 71, 72 and 73, or raised face members, that extend forward of the body, are disposed at an angle to each other, generally at a right angle to each other, and provide leading edges 50, 51-55. The plate 70 extends forward from the junction 32 of the raised ribs to the stepped leading edges 50, 52 and 51, with the stepped leading edge 51 being centrally located. Each edge is a chisel shaped penetrating tip. Plates 70 and 71 may be considered one plate and plates 72 and 73 may be considered a second plate, the two plates being interdigitated, and for purposes of this description these plates may be considered four separate plates extending radially from a common junction. More or fewer plates may be provided, and although the leading edges 53 of plates 72 and 73 are shown spaced axially behind the leading edges 51 of plates 70-71, it should be understood that the two plates may extend forwardly from the body an equal amount, as shown in FIG. 4. Preferably, the plate provides an anti-rotation surface to resist rotation of the anchor during driving. To this end, the plate extends 1/3 about the total length of the anchor as the starting point of the plate is measured from point 32, representing the forward end of the body 11 in front of the conical or transition region 12. The plate will extend approximately 20% of the total anchor length as measured from the end of the transition region 12. Although these percentages may vary, it is preferred that the plate extend 20-40% of the total length as measured from point 32 and that the plate project forward 15-25% of the length as measured from point 33 at the end of the transition zone. This provides sufficient anti-rotation surface to assist in the straight driving of the anchor. Although the top and bottom surfaces of the plates 70-73 may be formed parallel to each other, they may be distributed at an angle. Plate 71 is in mirror image relationship to plate 70 on the other or bottom side of the anchor, plates 70 and 71 being separated by horizontal plates 72, 73, horizontal plates 72, 73 similarly projecting from the junction of the main body and conical section 12 and being mirror images to the left and right. The plates 72, 73 may terminate in stepped (setback) chisel edges 53, 54, and there may be another central edge extending to the apex 51 if desired, although i prefer to use a single chisel leading edge 51. Although an X-shaped or cross-shaped leading edge is shown consisting of four equally spaced plates at right angles to each other, it will be appreciated that other combinations may be used. For example, the bottom plate 71 may be removed so that the front protrusion is substantially T-shaped. It will be appreciated that the plate 70 cannot be easily deleted because it merges rearwardly into the raised rib. While the front projection is alternatively described as a plate, or plate-like member, this is for descriptive purposes only, and it is understood that the entire anchor may be formed as a single casting, the projection may have a cross-sectional curvature or may project upwardly or downwardly near its outermost edge. It should also be understood that the top surface of plate 70 or the bottom surface of plate 71 or the sides of plates 72 or 73 may be chisel shaped. The term chisel edge as used herein includes all forms of sharp edges, including those having a radius at the outermost point. This does not mean a chiseling surface as sharp as a knife edge that is dangerous to handle, but rather the surface should not be blunt as the full thickness of the plate.

In addition, ribs 80 and 81 are located on each side of the body at locations on the outer edges of the plates 72 and 73 and spaced from the last stepped leading edge 54, and may have a substantially triangular chisel shaped leading edge 55 terminating in an outer edge of the rib which is chisel shaped or pointed as shown at 90, 91 in fig. 3. The leading edge 55 and ribs 80, 81 have a width from the outer diameter of the body that is relatively small, preferably about 20% of the diameter of the body 11. These ribs are not designed to act as wings as in winged anchors, but rather counteract the tendency of the raised ribs to deflect the anchor from a straight path upon driving. By having the ribs 80, 81 extend the full length from the front of the forward end of the transition section 12 to the rear edge 13 of the main body, by keeping the ribs relatively narrow and making them V-shaped in cross-section, they do not significantly increase the resistance of the anchor as it is driven into the soil, but serve to facilitate the straight driving of the anchor. It will be appreciated that as the anchor is driven into the ground, the force of the soil against the leading face 30 of the raised rib will have a tendency to cause the anchor to pivot upwardly in front of it, or to push the entire anchor downwardly. The ribs 80, 81 serve to help resist this tendency without significantly increasing the resistance of the anchor to driving into the ground.

Although a preferred embodiment has been described with only two ribs aligned with the centre line of the longitudinal axis of the anchor and starting from the edges of the plates 72, 73, the invention can alternatively be used by providing, for example, two ribs per side or by providing the ribs higher or lower along the sides of the body so as not to be coplanar with the plates 72, 73.

I have chosen to use relatively flat plates 70-73 to define the extended projection in front of the body of the anchor, since those flat surfaces also act to resist drift of the anchor. Others may choose different shapes or sizes for the protrusion, e.g. the plate is not provided with the same uniform thickness, but may be thinner at the front and increase in thickness towards the main body.

Furthermore, I have shown that the leading edges 50-54 and 55 are arranged substantially at right angles to the longitudinal axis of the anchor, and these edges may be inclined rearwardly if desired.

These and other variations of the invention will be apparent to those skilled in the art. For example, although I have illustrated and described a substantially cylindrical or elliptical anchor, the anchor body may be rectangular, octagonal, or other shape. In summary, when i use the term "substantially cylindrical", i intend to include all such minor shape variations.

Claims (11)

1. An earth anchor comprising a substantially cylindrical body having front and rear ends and top and bottom portions; a longitudinal axis; an everted lip at the posterior end; a raised rib extending radially outward from the top of the body portion, the raised rib having a leading surface and defining a connection point for connecting a tension member; at least one first substantially plate-like member extending from the front end of the body, terminating in a leading edge spaced from the body and having top and bottom corner faces, the leading edge including a plurality of individual chiseled edge sections stepped rearwardly from adjacent axially outwardly disposed edge sections toward the body and outwardly from adjacent edge sections substantially perpendicular to the longitudinal axis, the stepped rearwardly-directed edge sections being disposed on either side of a plane parallel to a longitudinal plane intermediate the top of the body from which the rib projects and a body bottom of the body opposite the rib, the first substantially plate-like member having a top corner face extending rearwardly from a radially outermost chiseled leading edge toward the body and aligned with the leading face of the raised rib, the ground anchor further including a top corner face disposed on either side of the body intermediate the top and the bottom and at least from the body At least one rib extending from said front end of said body to said rear end of said body, said side ribs being substantially V-shaped in cross-section perpendicular to said longitudinal axis and each side rib having a single chisel leading edge, wherein the single chisel leading edge of the V-shaped side rib is spaced from the leading edge of said ground anchor and said side rib projects from said anchor body a distance of 20% or less of the width of said anchor body.

2. The anchor of claim 1 including a second substantially plate-like member extending from said front end of said body and terminating in a set of chisel shaped leading edges on each side of said first substantially plate-like member, the chisel shaped edges on each side of said second substantially plate-like member being axially and radially spaced from each other as said edges increase in distance from said first plate-like member.

3. The anchor of claim 2, wherein an innermost leading edge of the second substantially plate-like member extends radially outward from the first plate-like member and is disposed axially rearward of the leading edge of the plate-like member.

4. The anchor of claim 2, wherein an innermost leading edge of the second substantially plate-like member extends from the first plate-like member and projects from the body portion a distance approximately equal to a distance that a furthest leading edge of the first substantially plate-like member projects from the body portion.

5. The anchor of claim 2, wherein the side ribs are coplanar with the second substantially plate-like member.

6. Anchor according to claim 5, in which the leading edge of the lateral rib is situated in front of the body.

7. The anchor of claim 2, wherein an angled transition region is provided between the leading end of the body and the first and second substantially plate-like members, the transition region terminating at a location spaced rearwardly of the leading edges of the first and second substantially plate-like members and forming an angled surface for deflecting matter from the leading end of the body as the anchor is pressed into the ground.

8. The anchor of claim 7, wherein the transition region is partially tapered.

9. A substantially cylindrical inclined ground anchor comprising an anchor body having a front end and a rear end, a blind bore extending into the anchor body from the rear end, a portion of the rear end defining an out-turned lip arranged to bite into soil adjacent the rear end after the anchor is driven into the ground, the anchor body having a projecting rib projecting from the anchor body on the opposite side of the anchor body to the out-turned lip when a pulling force is applied to the anchor to draw the anchor out of the ground, the projecting rib defining a connection point for connection to a tension member, the anchor body having a pair of projecting plates extending forwardly from a leading edge of the anchor body, the plates being arranged at an angle to one another and interconnected at an intersection point, each of the plates having a leading edge, and each of the leading edges being defined by a set of stepped rearwardly facing chisel edges from a central chisel edge to each side of the central chisel edge, the anchor body also has an inclined surface transition region between the front end of the anchor body and the leading edge of the plate, the inclined surface transition region deflecting material from the plate away from the anchor body during insertion of the anchor into the ground, the anchor body also having ribs extending substantially the length of the anchor body on opposite sides of the anchor body, the ribs each having a height from the top to the bottom, a chisel shaped leading edge terminating intermediate the top and bottom and a substantially V-shaped outer edge spaced from the anchor body, the ribs projecting from the anchor body a distance of 20% or less of the width of the anchor body.

10. Anchor according to claim 9, in which the rib has a leading edge in the form of a chisel located in front of the anchor body.

11. Anchor according to claim 9, in which at least one of the plates extends from the front end of the anchor body over 30-35% of the total length of the anchor.