US 2362556 A
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Patented Nov. 14, 1944 EARTH ANCHOR David C. Hubbard, Centralia, Mo., assignor to A. B. Chance Company, Centralia, Mo., a corporation of Missouri Application November 7, 1942, Serial No. 464,916
The present invention relates to earth anchors, and is particularly concerned with that type of earth anchor adapted to be inserted in a bored hole by means of a guy rod and adapted to have its movable wings expanded into engagement with the undisturbed earth surrounding the bore.
One of the objects of the invention is the provision of an improved earth anchor adapted to utilize a minimum amount of metal and having the major portion of its structure made of nonmetallic materials, such as hardwood, which are readily available in spite of the present scarcity of metal.
Another objectI of the invention is the provision of an improved earth anchor of the class described, which is provided with an improved form of expanding wings, which are adapted to be guided more certainly into the proper Vexpanded position.
Another object of the invention is the provision of an improved anchor structure of the class described, in which the expanding wings are suitably pivoted together and centered on the guy rod in such 'manner that they cannot get out of proper alignment and so that they are adapted to be expanded equally toward both sides.
Another object of the invention is the provision of an improved expanding anchor of the class described provided ,with suitable means for spreading the thrust force on the anchor over a predetermined area for increasing the strength of the assembly and increasing the resistance toward movement of the expanded anchor.
Another object of the invention is the provision of an improved expanding anchor adapted to be constructed of wood, and which is adapted to be manufactured at a low cost, and which is sturdy, and capable of being used for a long period of time.
Another object of the invention is the provision of an improved expanding anchor adapted to be constructed of wood, which is adapted to utilize to the fullest extent the ultimate holding power of the soil in which it is to be used.`
Another object of the invention is the provision of an expanding anchor adapted to be constructed of wood, which is so constructed as to permit the salvage of the guy rod by abandoning the anchor and screwing the guy rod out of the threaded member which is located below the anchor.
Other objects and advantages of the invention will be. apparent from the following description and the accompanying drawing, in which similar characters of reference indicate similar parts throughoutthe separate views.
Fig. `l is a side elevational View of an anchor embodying my invention in which the anchor wings are secured together at the top by a pair oi bendable strips;
Fig. 2 is a side elevational view of the anchor of Fig. l, taken from the right side of Fig. 1, also showing a feature which permits the salvage of the guy rod;
Fig. 3 is a View showing the preferred form of anchor in expanded position;
Fig. 4 is a, top plan View of the anchor in the position of Fig. 2; and
Fig. 5 is a top plan view of the anchor in the position of Fig. 3. I
Referring to the drawing, Figs. 1 to 5, l0 indicates an anchor assembly which preferably includes a guy rod Il, an expanding or wedging member I2, and a pair of anchor wings I3, I4. The guy rod Il is preferably of the type having a suitable eye at its upper end for engagement with a cable, and having a lower threaded end portion I5 provided with a nut I6.
The nut preferably engages a metal pressure plate il for distributing the thrust caused by a pull on the guy rod over a larger area of the expanding member I2.
The expanding member I2 and wings I3, I4 are preferably made of hard wood, such as oak.
The expanding member may comprise a sub-V stantiallyA cylindrical Wooden body, having a plane lower surface I8 for engagement with the thrust plate I'I.
This expanding member is provided with a cylindrical through bore I9-for passing the guy rod II.` Atits upper end its diametrically opposite sides are provided with beveled, sloping, camming surfaces 20, 2|, which take the form of plane surfaces, having a curved lower boundary, as shown in Fig. 1. I The anchor wings I3, I4 are preferably similar in shape and structure, but are oppositely located. Each of these'wings may comprise a flat wooden member having the plane upper and lower surfaces 22, 23.`
The upper corner is preferablybeveled off at 24, and the end corner may be beveled off at 25 (Fig. 5)'. I3, I4 there is a. beveled camming surface 26 or 2l, and these beveled camming surfaces preferably have the same angle with respect to the major axis of each wing as the `angularity of the camming surfaces 20, 2| on the Wedge I2.
Thus these end portions 26, 21 preferably t At the lower inner side of each wing l against the camming surfaces 20, 2| when the anchor is not expanded as shown in Fig. 2.
The two wings each have a partially cylindrical groove ,28 or 29, forming lan oval bore slightly larger than the diameter of the guy rod, as shown in Fig. 5, so that there will be room for the guy rod, even when the wings pivot out to the position of Figi-l.
'The two wings are preferably secured together by a hinge means, which may consist of a pair of flexible straps of bendable material, preferably metal. These straps are indicated by the numerals 50 and 5I. Each strap is of substantially U shape, and it is provided `with apertures in its legs for receiving thewood screws52, ,53, which secure the straps to the blades I3, I4.
The straps are preferably symmetrically 1ocated on the opposite sides of the guy rod '-II, and banding may take place in the strap at any point in the top part or yoke 54 when the wings are expanded as shownin-Fig. 3.
Another feature of this Vanchor is that the nut I6 may-be welded asat-55to the pressure plate I\'I, and the pressure plate I I may be securedby means of the screw bolts -56 and'SI to the bottom of the body I2. Thus, the nut cannot turn without turning uthe-body when the guy rod H is rotated, and after'the anchor-hasbeen expanded as shown in-Fig. 3 lthe guy-rod may be removed by rotating it in a counter-clockwise direction, while the'nut,plate, and anchor are held in fixed position by the-earth. This per- 4 mitsAthe-salvage ofthe guy-rod when the anchor is no longer to be used.
- The operation of the earth anchor -is as follows:
A bore is made in the earth, usually extending diagonally into -the ground Ain the direction in which the guy rod is to extend. This bore is preferably only slightly larger than the external diameter of the contracted anchor assembly shownin Fig. 4.
Theanchor is placed on the guy rod; and using the guy rod as a handle, the anchor assembly is moved to the bottom of the bore in the earth. A tamping member, -which preferably engages both wings at once, and `has a slot for the guy rod II, is then used to tamp on fthe ends'of the wings, forcing them downward. The camming surfaces 26, 21 slidably engage the camming surfaces 20, 42fI and cause the wings to expand, and the relatively sharp `points '42 on the wings cause them to penetrate the earth as the wings expand.
In Fig. 3 the anchor is lshown in `fully expanded position; yand it is `found that by means of this specific structure the holding power of the anchor is increased approximately -three hundred percent, over a similar expanded anchor the blades of which are not joined or hinged at the top.
The increased .holding -power of an anchor constructed .according to the invention, over an unexpanded anchor of the 4same size but not adapted `to engage the undisturbed earth, would be on the -order of one thousand percent.
The value of the expanding blades vin the anchor constructed according to the invention, lies in the fact that they penetrate into undisturbed earth, having a much higher retaining strength than the disturbed earth that is retamped into the hole.
One ofthe important features of the invention is that lthe blades shall be secured together at the top ,by some means for preventing spreading.
onally across the opposite corners of a square b ose. This structure has the advantage of being -more economical and of giving good holding power results.4
Suchan anchor, however, was not capable of utilizing the-.ultimate strength of the soil as the anchors of square shape reached their` ultimate strength and were completely destroyed, whereas the anchors with the round base as shown herein attain the ultimate strength of the soil without serious damage-to' the anchor.
lIt-will"thus be observed thatIhave invented an -improvedrform ofearth anchor, most ofthe parts of ywhich may-be made out of-wood, so that metal may be conserved and suitable anchors provided at a minimum cost.
The present anchorsarefsturdy and serviceable when'made out of v'hardwood orzwood which has a minimum tendencyto-rot, yand-they provide a firm-anchorage for fguy rods which will enable them to replace the metal anchors of the-prior art.
While I have illustrated a preferred yembodimentof vmy'invention, many modifications may be made without'departing from-the spirit of the invention, and Ido-'not wish to be limitedfto the precise details o'fconstruction set forth, but desire to avail myself of all changes within the scope of the appended claims.
Having thus described vmy invention, what I claim as new and desireI to -secure by -Letters Patent ofthe United Statesfls:
-L In an earth Vanchor lthe -combination of Aa substantially cylindrical lvbody Lhaving an axially extending'bore with Laguyrod'having a threaded lower end, extending through and projecting from said bore, said cylindrical member having a pair of diametrcally oppositely disposed acutely '-beveled surfaces on its upperend and having means on its lower -end for supportingand preventing rotation of a nut carried by :the-threaded end of saidguy rod, a pair Cif-expanding members comprising thick members,-one disposedoneach side of said guy rod and extending longitudinally of said guy rod, said expanding members being provided on their linner lowersides with'acutely beveled surfaces 4substantially parallel to the 'beveled surfaces on said cylindrical `memben'therebyl forming sharp edges at the outer lower portions 'of said expanding members, and said expanding members being formed at their upper edges with flat surfaces for engagement witha tamping bar, and a ypair of 'bendable metal straps 'located on each side of said vguy rod, said straps being secured to said expandable members with the expandable members in the folded .position which is substantially parallel to said ,guy rod whereby `,an axial thrust applied to the expandable members at Itheir upper 4ends causes Vthe expandable members to `be .spread `'due to the camming action of the said beveled surfaces until the expandable members have :their -sharp edges driven into the adjacent'earth in an `anchorholel .12. -In an earth anchor l.the combination 'of la substantially cylindrical body having an axially extending bore with a guy rod having a threaded lower end, extending through and projecting from said bore, said cylindrical member having a pair of diametrically oppositely disposed acutely beveled surfaces on its upper end and having means on its lower end for supporting and preventing rotation of a nut carried by the threaded end of said guy rod, a pair of expanding members comprising thick members, one disposed on each side of said guy rod and extending longitudinally of said guy rod, said expanding members being provided on their inner lower sides withacutely beveled surfaces substantially parallel to the beveled surfaces on' said cylindrical member, thereby forming sharp edges at the outer lower portions of said expanding members, and said expanding members being formed at their upper edges with flat surfaces forengagement with a tamping bar, and a pair of bendable metal straps, one located on each side of said guy rod, said straps being secured to said expandable members with the expandable members in the folded position which is substantially parallel to'said guy rod, whereby an axial thrust applied to the expandable members at their upper ends causes (the expandable members to be spread due to the camming action of the said beveled surfaces until the expandable members have their sharp edges driven into the adjacent earth in an anchor hole, said straps being of substantially U-shape and the downwardly extending legs of each strap engaging outside of said expanding members.
DAVID C. HUBBARD.