US3785100A

US3785100A - Ground anchor

Info

Publication number: US3785100A
Application number: US00242036A
Authority: US
Inventors: H Watanabe
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-05-10
Filing date: 1972-04-07
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15
Also published as: DE2222734B2; DE2222734A1; GB1383824A; JPS5610415B1

Abstract

A three- or four-point support type ground anchor is provided which may be easily driven into and positively set in the ground and may provide the maximum effective earth bearing surface area. The ground anchor comprises an inverted U-shaped resisting or earth bearing plate whose leg portions or resisting members may be bent outwardly in the opposite directions from each other successively along several horizontal lines. Until the ground anchor is driven to a predetermined depth, the bending of the resisting plate, that is the resisting members are prevented by a pair of driving-control rods so that they may be straightly driven into the ground. After the ground anchor has been driven to a predetermined depth, the driving control rods are released so that the resisting members may come off the control rods and follow the curved paths in the opposite directions. The load from the structure through a guy strand may be positively supported by the resisting plate, a pair of lift plates, and a pair of lift rods joined to the lower ends of the resisting members and an auxiliary rod or rods joined to the upper end of the resisting plate.

Description

Waite Watanabe aent H 1 Jan. 15, 11974 GROUND ANCHOR [22] Filed: Apr. 7, 1972 [2]] Appl. No.: 242,036

Related US. Application Data [63] Continuation-impart of Ser. No. 86,814, Nov. 4,

1970, Pat. NO. 3,662,505.

[30] Foreign Application Priority Data May 10, 1971 Japan 46/30425 [52] US. Cl. 52/162, 52/164 [51] lint. Cl E02d 5/80 [58] Field of Search 52/155, 158, 160, 52/162, 163, 164,165

[56] References Cited UNITED STATES PATENTS 3,662,505 5/1972 Watanabe et a1 52/164 X 853,331 5/1907 Alyea r 52/164 2,029,740 2/1936 Rosner 52/162 3,276,173 10/1966 Bowman et al. 52/164 3,601,941 8/1971 Watanabe et a1 52/162 X 7 Primary Examiner-Frank L. Abbott Assistant Examiner-John R. Masterman Att0rneySaul Jecies [57] ABSTRACT A threeor four-point support type ground anchor is provided which may be easily driven into and positively set in the ground and may provide the maximum effective earth bearing surface area. The ground anchor comprises an inverted U-shaped resisting or earth bearing plate whose leg portions or resisting members may be bent outwardly in the opposite directions from each other successively along several horizontal lines. Until the ground anchor is driven to a predetermined depth, the bending of the resisting plate, that is the resisting members are prevented by a pair of drivingcontrolrods so that they may be straightly driven into the ground. After the ground anchor has been driven to a predetermined depth, the driving control rods are released so that the resisting members may come off the control rods and follow the curved paths in the opposite directions. The load from the structure through a guy strand may be positively supported by the resisting plate, a pair of lift plates, and a pair of lift rods joined to the lower ends of the resisting members and an auxiliary rod or rods joined to the upper end of the resisting plate.

4 Claims, 12 Drawing Figures PATENYEDJM 15 1914 I sum it? 7 L51 7 J IE. 5.

GROUND ANCHOR This is a continuation-in-part of my prior patent application, Ser. No. 86,814, filed on Nov. 4, 1970, now U.S. Pat. No. 3,662,505.

BACKGROUND OF THE INVENTION The present invention relates to a stationary ground anchor to be driven into and set in the ground for guying a wood pole or steel tower for power transmission or an antenna structure.

The conventional ground anchors which have been widely used are of one-point support type generally comprising a relatively small steel resisting plate, which is driven into the ground, and a guy wire connection rod attached to the center of the upper surface of the resisting plate. In order to support a greater load or structure, the improved ground anchors of two-point support type have come to be used in which a guy connection rod is attached to the lower end of a resisting plate whereas an auxiliary rod to the upper or base end of the resisting plate so that the latter may hold a load at two points. Therefore the resisting plate may develop excellent holding power by bearing against undisturbed earth in a stable manner. However, even these twopoint support type ground anchors are unable to develop sufficiently high holding power for guying large structures which have recently become greater and greater. Furthermore when a resisting plate having a large earth bearing surface area is used, it becomes extremely difficult to drive it into the ground in one direction over a long distance to a predetermined depth cutting through the earth against the increasing soil resistance.

In order to overcome this problem, there has been proposed a ground anchor of the type in which two separate resisting plates are driven into the ground in such a manner that they may be integrally joined together in the ground. However, the ground anchors generally develop holding power by bearing against undisturbed earth by the resisting plate in the direction in which the uplift is applied to the ground anchor, so that the latter must be driven into the ground with the least soil resistance to a predetermined depth and then must be so positioned as to bear against undisturbed soil in the direction in which the lifting force is applied. In this respect, the conventional ground anchors of the aforementioned type have the defect that they are not set in the ground as desired because the ground anchor which is being driven into the ground cannot be seen from the ground surface and cannot be controlled in position. This defect is very serious especially when the ground anchor is driven by the conventional method into and set in ground in which the soil has been compacted very hard.

SUMMARY OF THE INVENTION It is therefore the primary object of the present invention to provide an improved ground anchor which may overcome the problems and defects encountered in the conventional ground anchors.

Briefly stated, the present invention is characterized in that an inverted U-shaped resisting or earth bearing plate is made by bending a steel plate having a ridge portion which is outwardly bulged along the longitudinal center line of the steel plate, each of two leg portions (which will be referred in this specification as resisting members) having a series of reinforcing members which are formed by dividing the ridge portion by grooves, when driven into the ground the leg portions or resisting members being bent outwardly away from each other successively along the grooves between the reinforcing members under the blows given to the ground anchor in combination with the soil resistance so that the resisting members may be set in the ground with desired curvature.

The present invention is further characterized in that a driving-control rod is inserted into each of the series of reinforcing members of the resisting members so that they may be prevented from being bent and may be driven straight to a desired depth, and when the ground anchor has reached the desired depth the control rods may be released and left in the ground upwardly relative to the resisting members due to the inertia of the driving-control rods when the ground anchor is further driven into the ground to permit the resisting members to come off the driving-control rods and to follow the curved paths in opposite directions, whereby the resisting members may be set in correct position in the ground to provide sufficient soil bearing surface areas.

The present invention is further characterized in that the lower ends of lift plates, which in turn are joined to lift rods, are attached to the lower or leading ends of the resisting members and the lower end or ends of auxiliary rod or rods are attached to the upper end of the resisting plate whereas the upper ends of these lift rods and auxiliary rod or rods are coupled to a guy wire connection rod so that the ground anchor may support a load at three or four points.

The ground anchor in accordance with the present invention is simple in construction, and may be easily driven into and set in ground so that the excellent holding power may be developed.

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a first embodiment of a ground anchor in accordance with the present invention;

FIGS. 2 and 3 are side and perspective views thereof;

FIG. 4 is a front view of a driving pipe with driving control rods used for driving the ground anchor of the present invention shown in FIGS. 1 3;

FIG. 5 is a top view thereof;

FIG. 6 is a front view of a driving rod used in conjunction with the driving pipe shown in FIG. 4;

FIGS. 7 11 are views used for explanation of the method and process of driving the ground anchor of the present invention; and

FIG. 12 is side view of a second embodiment of the present invention which is shown as being set in the ground.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings and particularly to FIGS. 1, 2 and 3, the first embodiment of a ground anchor in accordance with the present invention will be now described in detail. A ground anchor generally designated by 20 comprises a resisting plate 21, the most important part of the ground anchor, which is made of a rectangular plate whose four corners are cut off at an appropriate angle as best shown in FIG. 1 and which is formed with a ridge extending along the longitudinal axis of the plate. The rectangular plate is bent symmetrically back upon itself along the horizontal center line into the inverted-U-shape best shown in FIG. 3. Thus the resisting plate 21 comprises two resisting members 21a and 21b and a plurality of reinforcing members 24a1 24a6 and 24bl and 24b6 (in the instant embodiment each resisting member being shown as having six reinforcing members) which are formed by cutting the longitudinal ridge at 23a] 23a5 and 23b1 and 23b5 so that the reinforcing elements 2401 24a6 and 24b1 24b6 may be spaced apart from each other by an appropriate distance. As best shown in FIG. 3, a portion of the ridge at the top of the resisting plate 21 is cut off to provide an opening 22. It is seen that the longitudinal ridge may be formed by an appropriate metal forming method.

To the lower ends of the resisting members 21a and 21b of the resisting plate 21 are securely fixed, for example by welding, control or guide plates 25a and 25b which have sharp edges and extend downwardly beyond the leading lower edges of the resisting members 21a and 21b. These control or guide plates 25a and 25b serve to cut through the earth and guide the resisting plate 21 when it is driven into the ground. When forces in excess of a predetermined magnitude are exerted upon the resisting members 21a and 21b so as to move them away from each other outwardly, they are bent outwardly along the grooves 23a1 23:15 and 23b1 23b5 between the reinforcing elements 24111 24aand 24b1 24b6 until the adjacent reinforcing members abut against each other as will be described in more detail hereinafter. Thus, when the space between the reinforcing members 24al 24a6 and 24b1 24b6 is appropriately determined, a desired curvature of the bent resisting members 210 and 21b will be obtained. According to the present invention, and in order to facilitate the bending of the resisting members 21a and 21b, elongated grooves 26a1 26a5 and 26b1 26b5 having an appropriate length are formed in the resisting members 21a and 21b in line with the grooves 23al 23:15 and 23b1 23b5 on both sides of the ridge or reinforcing members. It is seen that in place of the elongated grooves, recesses may be formed.

The lower ends of the lowermost reinforcing members 24:11 and 24bl are closed by sealing and impactreceiving end members 27a and 27b, respectively, which are fixed to the reinforcing members by welding or the like so that the ground soil may be prevented from entering into the lowermost reinforcing members 2401 and 24bl and the blows for driving the ground anchor into the ground may be transmitted to the resisting members 21a and 21b as will be described in more detail hereinafter.

Impact-receiving members 280 and 28b are firmly attached at right angles relative to the control or guide members 25a and 25b, for example by welding, to the control or guide members 25a and 25b and to the lowermost reinforcing members 24a and 24b1 along the longitudinal axes thereof. As best shown in FIG. 2, the pointed edges of the impact-receiving members 28a and 28b extend downwardly beyond those of the control members 250 and 25b. These impact-receiving members 28a and 28b serve to cut through the soil when the anchor is driven into the ground so that the driving of the resisting members 21a and 21b may be facilitated.

Auxiliary members 30a and 30b are securely attached to the lower portions of lift plates 29a and 29b respectively in such a manner as to form a space therebetween. The lower ends of lift plates 29a and 29b are pivoted with pivot pins 310 and 31b, respectively, to the impact-receiving members 280 and 28b which are inserted between the lift plates 29a and 29b and the auxiliary members 30a and 30b.

A pincetteor pincers-like lift rod 33 comprises two leg members 33a and 33b and a ring or eye portion 32, and the lower ends of the leg members 33a and 33b are split axially and fitted over the upper edges of the lift plates 29a and 29b so that they may be firmly fixed thereto, for example by welding. A guy-wire-retaining rod 36 has two

eyes

34 and 35 of which the lower eye 34 is loosely coupled with the eye 32 of the lift rod 33, as best shown in FIG. 1.

The lower end of an auxiliary rod 37a which is used to transmit the bearing force of the resisting plate 21, is fitted into a bulged portion 38a of the uppermost reinforcing member 24a6 and securely fixed thereto, for example welding. The auxiliary rod 37a extends through a coupling ring 39 firmly fixed to the lift rod 33 immediately below the eye 32, and the upper end of the auxiliary rod 37a is bent over so that it may engage with the coupling eye 39 as will be described in more detail hereinafter. The length of the auxiliary rod 37a extending upwardly beyond the coupling eye 39 is made equal to the distance between the pivot pin 31a of the lift rod 29a and the bulged portion 38a of the reinforcing member 24a6 for a reason to be described in more detail hereinafter.

Next referring to FIGS. 4, 5, and 6, a driving tool for driving the ground anchor described above into the ground, will be described. The driving tool generally comprises a driving pipe 50, two driving-control rods 55a and 55b extending downwardly from the lower end of the driving pipe 50, and a driving rod 60. The lower end of the driving pipe 50 is closed with an end member 52 which is firmly attached thereto by welding or the like and is provided with an elliptical hole 53 which is smaller than the cross section of the driving pipe 50. Along the minor diameter of this elliptical hole 53 is fixed a partition 54 so as to divide the hole 53 further into two smaller holes. The driving-control rods 55a and 55b whose diameter is smaller than that of the divided parallel holes extend in parallel to each other through these divided smaller holes to a predetermined length.

As best shown in FIG. 6, the driving rod generally indicated by comprises a rod member 61 which is longer than the driving pipe 50 and a hammer head 62 fixed to the lower end of the rod member 61. When the driving rod 60 is inserted into the driving pipe 50, and then raised and dropped, the driving impact is transmitted to the head 56 of the driving-control rods 55a and 55b.

Next the mode of driving the ground anchor will be described hereinafter. The driving control rods 55a and 55b are inserted into the reinforcing members 2401 24a6 and 24b1 24b6 of the resisting members 210 and 21b respectively until the lower ends of the control rods 55a and 55b abut the impact receiving end members 27a and 27b. The ground anchor 20 is vertically placed in a hole dug in the ground, with the impact-receiving members 280 and 28b directed downwardly as best shown in FIG. 7. The driving rod 60 is inserted into the driving pipe 50, and repeatedly raised and dropped so that the driving impact may be transmitted to the head 56 of the driving-control rods 55a and 55b and hence to the resisting members 21a and 21b through the impact-receiving ends 28a and 28b. As a consequence the ground anchor 20 is gradually driven into the ground. In this case, since the driving-control rods 55a and 55b are inserted into the reinforcing members 2401 24a6 and 24bl 24b6, the resisting members 21a and 21b are prevented from bending outwardly when the ground anchor is driven to a predetermined depth.

When the ground anchor 20 is set to a predetermined depth, the ground anchor driving operation is temporarily suspended so that the driving rod 60 may be pulled away from the driving pipe 50. Thereafter the ground anchor driving operation is resumed by directly giving heavy blows to the driving pipe with a large hammer or the like as shown in FIG. 8, so that the driving impacts are directly imparted to the upper edge of the resisting plate 21 and not to the lower end of the resisting plate 21. When the driving impacts are driven by the driving rod 60, the impacts are transmitted to the lower edges of the resisting members 21a and 21b through the control rods 55a and 55b and the impact receiving ends 27a and 27b. Since the driving impacts are not imparted to the driving-control rods 55a and 55b which are inserted into the reinforcing members 24al 24a6 and 24b1 24b6 of the resisting members 21a and 21b, these rods are left behind the resisting members 21a and 21b when the latter are driven into the ground under the blows directly given from the driving pipe 50. As a result the lowermost reinforcing members 24411 and 24b1 and hence the control or guide members 25a and 25b attached thereto are released from the driving-control rods 55a and 55b. That is, the resisting members 21a and 21b are gradually released from the control of the driving-control rods 55a and 55b which have so far served to drive the resisting members 21a and 21b straight into the ground. Thus, under the driving impacts imparted to the upper edge of the resisting plate 21 and under the influence of the soil pressures imparted to the lift plates 29a and 29b, the lift rod 33 and the end members 27a and 27b at the ends of the lowermost reinforcing members 24a1 and 24b1, the resisting members 21a and 21b are gradually bent toward the lift plates 29a and 29b, respectively, as shown in FIG. 9. That is, the resisting members 21a and 21b are bent along the grooves 23a1 and 23bl between the reinforcing members 24al and 24a2 and between the reinforcing members 24bl and 24b2 toward the lift plates 29a and 29b, respectively. Thus the resisting members 21a and 21b start to be driven along curved paths in the ground.

However, when bending of the resisting members 21a and 21b is permitted without limitation, the curvature of the driving paths is increased to such an extent that the driving of the resisting members 21a and 21b along the curved paths becomes impossible. Therefore the spacing between the reinforcing members 2401 and 24:12 and 24bl and 24b2 is so determined that the driving along the curved path of the resisting members 21a and 22b may be possible. That is, the curvature of the curved driving path is limited.

When the driving blows are successively applied to the driving pipe 50, the resisting plate members 21a and 21b are successively bent along the grooves be tween the reinforcing members 24al and 24a2; 24b] and 24b2; 24a2 and 24a3; 24b2 and 24b3; 24a3 and 24a4; 24123 and MM; and so on, and are driven into the ground following along the curved paths initially made by the control or guide members 25a and 25b. Therefore as shown in FIG. 10, the resisting members 21a and 21b are greatly moved away from each other and driven into the ground along respective curved paths, so that they may be set in the ground. Thereafter the driving pipe 50 is pulled out together with the driving-control rods a and 55b. Thus the driving of the ground anchor is completed.

When the ground anchor 20 is driven into the ground, the auxiliary rod 37a is pulled by the resisting member 21a and the top end 40a of the auxiliary rod 37a is engaged with the hook 40a when the ground anchor is finally set into the ground. Therefore the uplifting force exerting to the guy-wire retaining rod 36 is sustained by three parts, that is the two leg members 33a and 33b of the lift rod 33 and the auxiliary rod 37a so that the resisting plate 21 may support the load at three points, that is the right and left ends and the upper end. Thus, the desired strong and stable holding force may be produced.

When the resisting members 210 and 21b are driven into the ground along the curved paths in the manner described above, the lift plates 29a and 29b and the lift rod 33 are forced to displace themselves slantingly under the soil pressure. Therefore, when the soil is soft there arises no problem, but when the soil is hard, the leg members 33a and 33b of the lift rod 33 are bent as shown in FIG. 10. However, when the uplift load is 'once applied to the guy-wire-retaining rod 36, these leg members 33a and 33b are extended straight as shown in FIG. 11.

When the mechanical strength of the ground anchor is desired to be increased, there may be provided an additional auxiliary rod 37b similar in both construction and function to the first-mentioned auxiliary rod 37a. The lower end of the auxiliary rod 37b is inserted into a bulged'portion formed at the uppermost reinforcing member 24b6 and is securely fixed thereto by welding or the like, whereas the upper end portion is bent over as shown at 40b so that it may engage with the eye 39 when the auxiliary rod 37b is driven into the ground as in the case of the auxiliary rod 37a. Therefore, when the ground anchor is driven into the ground, the resisting plate 21 may in this case support the load at four points, that is at the right and left ends of the right and left resisting members, and also at the upper ends thereof. In other words, the resisting plate 21 is connected at these four points to the lift rod 33 through the lift plates 29a and 29b and to the auxiliary rods 37a and 37b, so that the sufficiently strong bearing force may be produced.

Only the essential features of the present invention has been described, and it will be understood that various modifications and variations can be effected without departing from the true spirit of the present invention.

What is claimed is:

l. A ground anchor, comprising a resisting plate of inverted U-shape;

a pair of lift rods having lower ends hinged to the lower ends of said resisting plate;

a guy-wire-retaining rod having a lower end coupled to respective upper ends of said pair of lift rods which are joined to each other; and

an auxiliary rod having a lower end joined to an upper end of said resisting plate,

said resisting plate being provided with a ridge portion which bulges outwardly along a longitudinal axis of said resisting plate and said ridge portion being divided into a plurality of reinforcing members which are spaced apart from each other by respective grooves so that said resisting plate may be easily bent outwardly along the grooves between said plurality of reinforcing members,

said auxiliary rod being loosely fitted into a coupling annulus formed at said upper ends of said pair of lift rods in such a manner that an upper end of said auxiliary rod engages with said coupling annulus when said ground anchor has been driven into and set in the ground.

2. A ground anchor as set forth in claim 1, wherein said plurality of reinforcing members are semi-elliptical in cross section and are spaced apart from each other by a predetermined distance so that said resisting plate may be bent with a predetermined curvature when said ground anchor has been driven into the ground.

3. A ground anchor as set forth in claim 2, wherein the lower ends of the lowermost reinforcing members of said resisting plate are closed with end members, wherein control or guide members are securely joined to rear surfaces of the lower end portions of said resisting plate in such a manner as to extend downwardly beyond said lowermost reinforcing members, and wherein driving-control rods are inserted through said plurality of reinforcing members until they engage with said end members so that when said ground anchor is driven into the ground said resisting plate may be maintained straight but when the driving impacts are directly applied to said upper end of said resisting plate said driving-control rods are left upwardly behind said resisting plate because of the inertia of said driving-control rods, so that the leg portions of said resisting plate are outwardly moved away from each other and follow curved paths in opposite directions.

4. A ground anchor as set forth in claim 3, wherein said resisting plate has an additional auxiliary rod whose lower end is also firmly fitted to said upper end of said resisting plate and which is loosely fitted into said coupling annulus together with the first-mentioned auxiliary rod, the upper end of said additional auxiliary rod also engaging with said coupling annulus when said ground anchor has been driven and set into the ground.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,785,100 Dated January 15, 197 O Inventor(s) Hikoitsu Watanable It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: .1

On the Cover Sheet, in item add the following:

-- and Sanji Genma, 4-8, l-ohome, Ebar'a-Cho, Nakano-ku,

Tokyo, Japan Signed and Scaled this fourteenth D a y of October 1 9 75 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (ummissiuner uj'Patents and Trademarks 'ORM PO-1050 (10-69) USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTING OFFICE: 3 I a l

Claims

1. A ground anchor, comprising a resisting plate of inverted U-shape; a pair of lift rods having lower ends hinged to the lower ends of said resisting plate; a guy-wire-retaining rod having a lower end coupled to respective upper ends of said pair of lift rods which are joined to each other; and an auxiliary rod having a lower end joined to an upper end of said resisting plate, said resisting plate being provided with a ridge portion which bulges outwardly along a longitudinal axis of said resisting plate and said ridge portion being divided into a plurality of reinforcing members which are spaced apart from each other by respective grooves so that said resisting plate may be easily bent outwardly aLong the grooves between said plurality of reinforcing members, said auxiliary rod being loosely fitted into a coupling annulus formed at said upper ends of said pair of lift rods in such a manner that an upper end of said auxiliary rod engages with said coupling annulus when said ground anchor has been driven into and set in the ground.