GB2073274A - Ground anchor - Google Patents

Abstract

A stay anchor comprising an elongated arcuate resisting plate 10 with a stiffening plate 20, a guide member 50 connected thereto and connected itself to a guy rod 60, a connecting member 100 one end of which is connected by means of a bracket 80 to the rear end of the outside surface of the resisting plate, the one end being so shaped that it forms an angle with the resisting plate such that in the fully driven position the connecting member 100 is substantially horizontal in the ground, and a guide member 180 which is pivotally connected at one end to the other end of the connecting member and which is adapted to be maintained in the substantially upright position when set in the ground, and a stabilising plate 140 which is driven into a predetermined depth along the uprightly held guide member and connected thereto. A method of driving using a specialised driving rod is described. <IMAGE>

Description

SPECIFICATION Stay anchor and method for driving the same The present invention relates to a stay anchor for retaining one end of a guy for bracing a structure such as poles and a method for driving the same.

It is the primary requirement for any ground and stay anchors or the like that they develop high holding power or resistance against the pull.

So far various types of stay and ground anchors have been devised and demonstrated, but all of them are straightly driven into the ground so that a sufficient holding power cannot be developed.

There has been and is an increasing demand for stay anchors which can develop higher holding power.

The primary object of the present invention is to provide a stay anchor which can develop heretofore unattainable holding power when set in the ground.

Another object of the present invention is to provide a method for driving a stay anchor in accordance with the present invention into the ground to a desired depth.

Briefly stated, the present invention provides a stay anchor comprising an elongated arcuate resisting plate with a stiffening plate, a guy plate and a guy rod as with the prior art stay anchors, a connecting plate which has its one end pivoted to the rear end of the outside surface of the resisting plate, said one end being so shaped that when it bears against the resisting plate, the connecting plate is maintained in the substantially horizontal position, a guide plate which has its one end pivoted to the other end of the connecting plate and which is maintained in the substantially upright position when set in the ground, and a stabilizing plate whose bearing surface is substantially equal in area to that of the resisting plate and which is driven into a predetermined depth along the uprightly held guide plate and physically connected thereto.

the above and other objects, effects and features of the present invention will become apparent from the description of a preferred embodiment thereof taken in conjunction with the accompanying drawings.

Fig. 1 is a side view of a stay anchor in accordance with the present invention with a stabilizing plate removed; Fig. 2 is a view used for the explanation of the relative angular movement between a connecting plate 100 and a guide plate 1 1 1; Fig. 3 is a front view of the stay anchor shown in Fig. 1; Fig. 4 is a rear view thereof; Figs. 5 and 6 are side and top view, respectively, of a stabilizing plate assembly; Figs. 7 and 8 side and front views, respectively, a driving rod used for driving the stay anchor shown; Figs. 9 through 13 are views used to the explanation of the steps for setting the stay anchor; and Fig. 14 is a view used for the explanation of the dependence of the tendency of the resisting plate to rotate upon the point thereon.

Referring to Figs. 1 through 4, a stay anchor in accordance with the present invention comprises, in general, an elongated arcuate resisting or first bearing plate 10 (to be referred to as "the resisting plate" hereinafter) with an elongated, arcuate stiffening plate 20, a guy plate 50, a guy rod 60, a connecting plate 100 and a guide plate 110. The resisting plate 10 is made of steel and provided with the stiffening plate 20 securely joined to the inside surface of the resisting plate 10 perpendicular thereto and extended along the center-line thereof over the whole length thereof.

As best shown in Figs. 1 and 3, the lower ends of the resisting plate 10 and the stiffening plate 20 are pointed so as to cut earth or soil, and the upper end of the resisting plate 10 is formed with an arcuate recess 30 for engagement with a driving rod to be described below. A bracket 40 for connection to the guy plate 50 is securely joined the upper edge of the stiffening plate 20 at such a position that, as will be described in detail below, the component of the pull P (See Fig. 13) which causes the rotation of the resisting plate 10 becomes maximum.

The lowe end of the guy plate 50 is pivoted to the bracket 40, and in order to maintain the desired relative angular position between the stiffening plate 20 and the guy plate 50, a stopper 70 is attached to the upper edge of the stiffening plate 20 for engagement with the guy plate 50 as best shown in Fig. 1. The upper end of the guy plate 50 is connected to the lower eye of the guy rod 60 with the upper eye for connection to a suitable guy (not shown).

A bracket 80 is securely joined to the outer surface of the resisting plate 10 adjacent to the upper end thereof, and the lower end of the connecting plate 100 is pivoted to the bracket 80 while the upper end thereof is pivoted to the bifurcated lower end 120 of the guide plate 110 having a connection hole 1 30 adjacent to the upper end thereof. in order to prevent the rotation of the connecting plate 100 in the counterclockwise direction through a predetermined angular position and securely maintaining the connecting plate in this position (See Fig. 13) for the purposes to be described in detail below, the lower end 90 of the connecting plate 100 is cut slantly as best shown in Fig. 1.

Referring next to Figs. 5 and 6, the stay anchor of the present invention further includes a flat and rectangular stabilizing or second bearing plate 140 (to be referred to as "the stabilizing plate" hereinafter) which has a bearing surface with an area substantially equal to that of the bearing surface of the resisting plate 10.The stabilizing plate 140 which is made of steel is provided with a rib 1 50 which, as best shown in Fig. 6, is substantially semicircular in cross section and is extended along the center-line (from the upper to lower edge) of the stabilizing plate 1 40. An elongated stiffening plate 1 60 is securely joined to the top of the rib 150 and serves not only for stiffening or reinforcing the stabilizing plate 140 but also for controlling the movement thereof when driven into the soil as will be described in detail below.A guide 170 which is elongated-Ushaped in cross section as best shown in Fig. 6 is securely joined to the surface of the stabilizing plate 140 opposite to the surface having the rib 1 50 and substantially at the center of the stabilizing plate 140 in such a way that the guide recess of the rib 150 and the recess of the guide 170 may define a guide passageway as best shown in Fig. 6. A setting-depth indicating rod 1 80 with a predetermined length is securely attached at its lower end to the guide 1 70 and is extended in parallel with the stabilizing plate 140.

In order to drive the stay anchor of the present invention and more specifically the resisting plate 10, the driving rod 190 of the type shown in Figs.

7 and 8 is used. The driving rod 190 has a length sufficient to drive the resisting plate 10 to a desired depth and the strength sufficient to withstand the driving impact that is applied to the top of the driving rod 190. A bracket 200 with connection holes 210 for connection with the upper end of the guide plate 110 is securely joined to the driving rod 1 90 at such a position that, as will be described in detail below, the guide and connecting plates 110 and 100 may be maintained in the desired angular position (See Fig. 10) when the stay anchor is driven into the soil. The lower end of the driving rod 190 is formed with a slot 220 for engagement with the arcuate recess 30 at the upper end of the resisting plate 10 (See Fig. 1).

Next the mode of operation for driving and setting the stay anchor with the above-described construction with the driving rod 190 will be described. As shown in Fig. 9, the stay anchor is erected upright with the pointed ends of the resisting and stiffening plate 10 and 20 resting on the bottom of a small-diameter hole dug to a desired depth and the upper ends of the guide plate 110 and the guy rod 60 resting on the ground.

As the impacts are applied to the upper end 30 of the resisting plate 10, the latter is gradually driven into the soil and the guy plate 50 is rotated in the clockwise direction while the connecting plate 100 in the counterclockwise direction.

However, by virtue of the provision of the stopper 70, the rotation of the guy plate 50 in the counterclockwise direction is limited so that the desired relative angular position (See Fig. 10) between the resisting plate 10 and the guy plate 50 may be maintained during the driving of the stay anchor and after the stay anchor has been set (See also Fig. 13).

After the upper end 30 of the resisting plate 10 has been driven closer to the bottom of the hole, the slot 220 of the driving rod 190 is engaged with the arcuateiy recessed upper end 30 of the resisting plate 10 while the upper end of the guide plate 110 is connected to the bracket 200 of the driving rod 190 with a bolt and a nut (See Fig. 10).

As the impacts are applied to the driving rod 190, therefore, the resisting plate 10 is further driven into the soil together with the guy plate 50, the guy rod 60, the connecting plate 100 and the guide plate 110 as shown in Fig. 1 0.

If the upper end of the guide plate 110 were not connected to the bracket 200 of the driving rod 190, the connecting plate 100 and the guide plate 110 would be extended straightly and in parallel with the driving rod 1 90 as they are pulled downward by the resisting plate 10 and encounter the resistance from the surrounding ground.

However, according to the present invention, the upper end of the guide plate 110 is connected to the bracket 200 of the driving rod 1 90. As a result, the connecting plate 100, the guide plate 110 and the driving rod 190 can be maintained in the desired relative angular positions as shown in Fig.

10 during the driving of the resisting plate 10.

After the guide plate 110 has been driven into the ground to a predetermined depth, the upper end thereof is released from the bracket 200 of the driving rod 1 90. Thereafter the driving force is applied to the upper end of the guide plate 110 so as to further drive the same into the ground. In this case, as the guide plate 110 is driven, the connecting plate 100 is caused to rotate in the counterclockwise direction about the pivot pin at the lower end, but when it is brought to a substantially horizontal position, the slantly-cut lower end 90 of the connecting plate 100 engages with the bottom of the bracket 80 of the resisting plate 10 so that no further rotation is permitted.

Thus, the connecting plate 100 and the guide plate 110 are set as shown in Fig. 11 and the driving rod 190 is of course withdrawn.

Thereafter the stabilizing plate 140 is erected upright at the bottom of the hole in such a way that the guide groove, that is the recess of the rib 150, is partly fitted over the left-side edge of the guide plate 110 which is partly extended beyond the bottom of the hole by a predetermined distance and held upright as best shown in Fig.

1 Thereafter the driving force is applied to the stabilizing plate 1 40 to drive it into the ground along the guide plate 110. When the lower end of the guide 170 of the stabilizing plate 140 engages with the upper end of the guide plate 1 0, the latter is inserted into the guide passageway (See Fig. 6), whereby the stabilizing plate 140 may be more positively guided by the guide plate 110.

When the upper end of the stabilizing plate 140 is almost driven into the ground, the driving rod 190 is also used to drive the stabilizing plate 140 further into the ground in a manner substantially similar to that described above in conjunction with the driving of the resisting plate 10. Therefore the upper end of the stiffening plate 160 may be arcuately recessed as indicated by 30 in Fig. 12.

The stabilizing plate 140 is driven until the lower end of the guide 1 70 engages with the upper edge of the connecting plate 100. Then the upper end of the setting-depth indicating rod 1 80 becomes almost in line with the upper end of the guide plate 110 as shown in Fig. 12, whereby an operator may visually confirm that the stabilizing plate 140 has been driven to a predetermined depth. Thereafter the hole is refilled as shown in Fig. 13, whereby the setting of the stay anchor is completed.

If the connecting plate 100 and the guide plate 110 were forcibly maintained in the angular positions shown in Fig. 11 during the driving of the stay anchor, the connecting plate 100 would have to cut the ground along its whole length so that it would encounter tremendous resistances from the ground. As a result, the driving and setting of the resistance plate 10 to a desired position would be aversely affected. However, according to the present invention, the connecting plate 100 and the guide plate 110 are maintained in the angular positions as shown in Fig. 10 and as described elsewhere so that they may encounter a minimum degree of resistance from the surrounding ground when driven.

The stay anchor thus set can produce the resistance against the pull P to a degree hitherto unattainable by any prior art ground and stay anchors because of its very rational design as will be described in detail below.

Referring to Fig. 13, the pull P is applied through the guy rod 60 and the guy plate 50 to the point A; that is, the pin pivotably connecting the guy plate 50 and the bracket 40 in the direction indicated by the arrow. If the stay anchor consisted of only the resisting plate 10, the stiffening plate 20, the guy plate 50 and the guy rod 60, it would be readily pulled out of the ground.The reasons are that (a) the main holding power or resistance against the pull is developed only by the inside surface of the resisting plate 10 bearing against the undisturbed earth and that (b) there remains the open path as indicated by the one-dot chain line through which is driven the resisting plate 10 and (c) that the angle between the resisting plate 10 and the direction of the application of the pull P; that is, the angle of the wedge-shaped stopper 70, is very small so that the component acting perpendicularly on the bearing surface of the resisting plate 10 is small.

However, according to the present invention, the upper end of the resisting plate 10 is connected through the connecting plate 100, the guide plate 110 and the guide 1 70 to the stabilizing plate 140 which has the bearing surface area substantially equal to that of the resisting plate 10 and is driven vertically. As a result, the component of the pull P which tends to pull the resisting plate 10 out of the ground is overcome by the strong resisting forces mainly developed by the stabilizing plate 140. As a result, the stay anchor can develop the holding power to an extremely high degree hithertofore unattainable by any of the prior art ground and stay anchors.

In addition, the pull P is not directly applied to the resisting plate 10 but to the point A which is spaced apart from therefrom and the angle between the resisting plate 10 and the guy plate 50; that is, the direction of the pull P is maintained at a predetermined degree by the stopper 70 so that the pull P would inevitably cause the rotation of the resisting plate 10 about the point B; that is, the pin pivotably connecting the connecting plate 100 and the guide plate 110 against virtually unlimited resistance encountered from the undisturbed ground or earth. In other words, one of the most important features of the present invention resides in the fact that the stay anchor is so designed and constructed and the point A of the application of the pull P is so selected that all the pull P would cause this rotation of the resisting plate 10.Therefore the extremely high holding power is developed not only by the resistance encountered from the undisturbed ground when the bearing surface of the resisting plate 10 is forced to bear against it but also by the resistance encountered when the pull P causes the rotation of the resisting plate 10 about the point B. In this case the point B must be held stationary against the force acting on it. According to the present invention this force is resisted by the resistance R developed by the stabilizing plate 140, the line of action of the resistance R being coincident with the extension of the line interconnecting between the points A and B. The resistance R is developed when the stabilizing plate which has the same bearing surface area as the resisting plate 10 is forced to bear against the undisturbed ground.

When the resistance of the undisturbed ground against which bears the bearing surface of the resisting plate 10 is lowered, the resisting plate 10 is caused to rotate about the point C; that is the pin pivotably connecting the resisting plate 10 and the connecting plate 100.

The tendency to rotation of the resisting plate 10 is dependent upon the point A of the application of the pull P. This will be described in more detail with particular reference to Fig. 14. In general, as indicated by I, II and Ill, the closer the point A to the lower pointed end of the resisting plate 10 and the greater the perpendicular distance from the arcuate bearing surface thereof, the more rotation tendency is enhanced. On the other hand, the further the point A from the lower end and the shorter the perpendicular distance as shown at IV and V, the less the rotation tendency becomes. In the extreme case wherein the point A coincides with the upper end of the resisting plate 10, no rotation will occur at all.

This rotation tendency is also highly dependent upon the angle between the resisting plate 10 and the guy plate 50 and on the length of the connecting plate 100; that is, the distance between the resisting plate 10 and the stabilizing plate 1 40. Thus the point A must be so selected based upon the above-described factors that the stay anchor when set develops a maximum holding power.

Claims (9)

1. A stay anchor comprising an elongated arcuate resisting plate with a stiffening plate, a guide plate connected thereto and connected itself to a guy rod, a connecting plate one end of which is connected by means of a bracket to the rear end of the outside surface of the resisting plate, the one end being so shaped that it forms an angle with the resisting plate such that in the fully driven position the connecting plate is substantially horizontal in the ground, and a guide plate which is pivotally connected at one end to the other end of the connecting plate and which is adapted to be maintained in the substantially upright position when set in the ground, and a stabilizing plate which is driven into a predetermined depth along the uprightly held guide plate and connected thereto.

2. A stay anchor comprising an elongated arcuate resisting plate with a stiffening plate, a guide plate connected thereto and connected itself to a guide rod, a connecting plate one end of which is connected by means of a bracket to the rear end of the outside surface of the resisting plate, the one end being so shaped that it forms an angle with the resisting plate such that in the fully driven position the connecting plate is substantially horizontal in the ground, and a guide plate which is pivotally connected at one end to the other end of the connecting plate and which is adapted to be maintained in the substantially upright position when set in the ground, the point of application of force being selected on the stiffening plate along the centre line of the inside arcuate surface of the arcuate resisting plate in such a way that the said point tends to cause rotary movement of the resisting plate with respect to a first fulcrum point spaced from the resisting plate and that the magnitude of the upwardly directed pulling load required for rotation becomes maximum and the bracket and connecting plate being pivoted in such a way that the connecting plate is limited and stopped after a predetermined pivotal movement on the outside arcuate surface of the resisting plate.

3. A stay anchor as claimed in claim 2 in which a stabilizing plate having a resisting surface substantially equal or comparable in area to that of the resisting plate is engaged with the guide plate.

4. A stay anchor as claimed in claim 3 in which the first fulcrum point is coincident with the connection of the connecting plate and to the guide plate.

5. A stay anchor as claimed in claim 4 in which the centre line in the direction of the width of the stabilizing plate is formed as a rib of small size, a stiffening member is securely joined to the outer surface of the rib in the longitudinal direction thereof, a control ring is securely joined to the opposite flat surface in such a way that the lower end of the control ring is positioned substantially at the centre of the flat surface area of the stabilizing plate bridging across the rib and a depth measuring rod is securely joined to the side surface of the control ring.

6. a method of driving a stay anchor into the ground comprising the steps of connecting one end of a guide plate, the other end of which is pivoted to one end of a connecting plate whose other end is pivoted to the upper end of an arcuate resisting plate to a bracket rigidly connected to a driving rod for driving said resisting plate, driving the resisting plate with the connecting plate, the guide plate and the driving rod being maintained in predetermined angularly positioned relationship, pulling out the driving rod after the resisting plate has been set to a desired depth, releasing the guide plate from the driving rod, driving the guide plate, which is freed, on the longitudinal line thereof in the longitudinal direction thereof, and pivotally rotating the connecting plate in such a way that a stabilizing plate directly faces and drives the horizontal ground pressure against a component produced by the pull applied to said resisting plate.

7. A method as claimed in claim 6 in which the driving rod has a length corresponding to a setting depth a guide-plate retaining member having engaging holes is securely joined to the longitudinal side face of said driving rod, and an engaging slot is machined at the leading end of said driving rod.

8. A stay anchor substantially as described herein with reference to and as shown in the accompanying drawings.

9. A method of driving a stay anchor substantially as described herein with reference to and as shown in the accompanying drawings.