METHOD AND APPARATUS FOR CREATING A PREFERENTIAL BREAKAGE PLANE WITHIN CURED COLUMNS

Abstract

A frangibility device for creating a preferred breakage plane or weakness within cured columns such as rigid inclusions (RIs) and/or vibratory concrete columns (VCCs) comprises a cutting disc, an elongate strut attached to the center of the disc, and a detachable handle for turning. The disc comprises a thin geometric plate slit from center to periphery, so that a slicing wing can be bent downward at a shallow angle from the slit. The slicing wing advances the cutting disc through the cementious material of the uncured column. When the disc reaches the desired depth, the handle is removed and both disc and strut are left in place during curing.

Claims

1. A tool for cutting a cured column, comprising: a cutting member symmetric about a center of rotation and having a cement slicing wing extending radially from said center of rotation and presenting an edge canted downward at an angle; an elongate strut attached to the center of rotation of the cutting member; and a handle attached transversely to the strut for turning the cutting member; whereby turning said handle rotates said cutting member for slicing and advancement through uncured cementious material.

2. The cutting tool according to claim 1, wherein said cutting member comprises a geometric plate having any of a circular, square or polygonal geometry.

3. The cutting tool according to claim 1, wherein said cement slicing wing is formed along a slit in said cutting member extending from a periphery thereof toward said center of rotation.

4. The cutting tool according to claim 3, wherein said slit terminates at a point offset from said center of rotation.

5. The cutting tool according to claim 1, wherein said cement slicing wing is canted downward from said cutting member at an angle within a range of 5-25 degrees.

6. The cutting tool according to claim 1, wherein said cement slicing wing is canted downward from said cutting member at an angle of approximately 10 degrees.

7. A frangibility device for creating a preferred breakage plane within cured ground improvement elements, comprising: a cutting member comprising a thin geometric plate having a slit extending inward and bent at an angle along said slit to define a cement slicing wing for advancing the cutting member through uncured cementious material of said ground improvement element; an elongate strut attached to the center of the cutting member; and a handle removably attachable to the strut for turning the cutting member.

8. The frangibility device according to claim 7, wherein said cutting member comprises a geometric plate having any of a circular, square or polygonal geometry.

9. The frangibility device according to claim 7, wherein said cutting member comprises a geometric plate having a center of rotation.

10. The frangibility device according to claim 9, wherein said cement slicing wing is formed along a slit in said cutting member extending from a periphery thereof toward said center of rotation.

11. The frangibility device according to claim 10, wherein said slit terminates at a point offset from said center of rotation.

12. The frangibility device according to claim 10, wherein said cement slicing wing is canted downward from said member at an angle within a range of from 5-25 degrees.

13. The frangibility device according to claim 10, wherein said cement slicing wing is canted downward from said member at an angle of approximately 10 degrees.

14. A method of creating a preferred breakage plane within a cured column, comprising the steps of: rotating a cutting member to advance it through an uncured column, said cutting member having a cement slicing wing extending radially canted downward from said member at an angle, and thereby advancing said cutting member to a predetermined depth; curing said column; and excavating to break said cured column at said predetermined depth.

15. The method of creating a preferred breakage plane or weakness within a cured column according to claim 14, wherein said step of rotating comprises manual rotation of a removable handle attached to said cutting member.

16. The method of creating a preferred breakage plane or weakness within a cured column according to claim 15, further comprising a step of removal of said handle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:

[0015] FIG. 1 is a side perspective view of a frangibility device 2 according to the present invention.

[0016] FIG. 2 is a side profile view of the frangibility device 2 of FIG. 1 with enlarged inset of the disc 10.

[0017] FIG. 3 is a bottom view of the disc 10 of FIGS. 1-2 with exemplary dimensions.

[0018] FIGS. 4-6 are sequential views of the frangibility device 2 of FIGS. 1-3 collectively illustrating its method of use.

[0019] FIG. 4 is a perspective view prior to insertion of the frangibility device 2.

[0020] FIG. 5 is a perspective view illustrating downward insertion of the frangibility device 2.

[0021] FIG. 6 is a perspective view illustrating excavation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention is a frangibility device, simple in construction, with easy to use methods for creating weakness or a preferred breakage plane within cured columns such as rigid inclusions (RIs) and/or vibratory concrete columns (VCCs). As seen in FIGS. 1-3 the frangibility device 2 generally comprises a disc 10 having a mass center point P on an axis of rotation, and a diameter substantially equal to the design diameter of the RIs/VCCs to be precut. An elongate strut 20 extends along the axis of rotation, and a detachable handle comprising a socket 30 for insertion onto the strut 20 and an orthogonal hand grip 40 for turning. As seen in FIG. 2 the disc 10 comprises a thin geometric plate symmetric in a plane about an axis of rotation through mass center point P. The disc 10 may comprise a circular, square or polygonal geometric plate, the illustrated embodiment comprising an octagon. The disc 10 is slit at 12 along a first radius R1 running from a point offset slightly from the mass center point P to its periphery, and a section is bent along a second radius R2 downward to form a depressed wing 14 that inclines progressively downward at an angle from mass center point P along slit 12 toward the periphery. The wing 14 is preferably bent downward at an angle within a range of from 5-25 degrees, and most preferably (as seen in FIG. 2) at approximately a 10 degree angle.

[0023] The disc 10 may be formed by cutting a symmetric geometric figure from a sheet of steel, cutting a slit 12 along radius R1 and bending wing 14 downward along radius R2 at the desired angle. The slicing wing 14 presents a leading slicing edge 16, which may optionally be sharpened to slice through the uncured cement. Forming the slit 12 along radius R1 offset slightly (e.g., 16% as shown) from the mass center point P to its periphery makes it possible to complete the bend with distal pressure in a vice or the like. However, one skilled in the art should understand that other embodiments of the disc 10 are possible by other conventional molding or machining methods. For example, disc 10 may comprise a shallow helical plate in the nature of an auger, a circular plate having a radial slot and a downwardly-canted blade in arrears of the slot in the nature of a spiral slicing blade, or any other rotary member capable of advancing itself through and displacing the wet cement/grout upon rotation.

[0024] The elongate strut 20 may comprise any elongate member fixedly attached at mass center point P such as by welding to the disc 10 and extending coaxially along the axis of rotation of the disc 10. The elongate strut 20 preferably extends within a range of 30-50 inches, and optimally extends approximately 36 inches as seen in FIG. 2. The elongate strut 20 is keyed to the socket 30, and as illustrated the entire strut 20 may be formed from a square-tubular length of steel, the socket 30 being similarly formed with an interior hollow generally conforming to the exterior of strut 20 so as to slidably receive it. In an embodiment the elongate strut 20 may be demarcated lengthwise with length indicia to visually indicate insertion depth. The hand grip 40 is fixedly attached across an end of socket 30 and preferably extends equilaterally and orthogonally on both sides for turning by hand.

[0025] In use, the handle is inserted onto the strut 20 and hand-turned by hand grip 40, manually turning the disc 10 counterclockwise to screw it downward about mass center point P through an uncured concrete or cementious grout column such as an RI and/or VCC. The wing 14 serves to advance the disc 10 through the concrete or grout essentially shaving a volume, expelling it sideward, and advancing helically downward at R1 from mass center point P within a range of from 5-25 degrees, and most preferably (as seen in FIG. 2) at approximately a 10 degree angle.

[0026] The method of cutting begins with the concrete or cementious grout column still in uncured form. As seen at FIG. 4 the frangibility device 2 is assembled and disc 10 is brought to bear atop the column. As seen at FIG. 5 an operator manually turns the frangibility device 2 counterclockwise so that the disc 10 advances vertically downward into the column. The device 2 is advanced to the desired position at a given depth of the column. The depth may be indicated by the measurement indicia on strut 20 until it corresponds to a desired flat top level. Once the desired depth has been reached and checked. The handle including socket 30 and hand grip 40 are removed, as the disk 10 and strut 20 remain in place while the cement solidifies. As shown in FIG. 6, after curing, an operator manipulates an excavator to excavate the ground to the bottom of LTP elevation and in so doing snaps a sacrificial section of the column off. As a result of the strut 20 being embedded, the column breaks along a plane immediately below the disc 10 and an upper section of the column (with strut 20 embedded therein and disc 10 exposed) can be easily removed. The remainder of the column is now flat-top flush with the excavated surface and perfectly in line with the execution tolerances required. If desired, the cement or cementious grout surrounding the strut 20 and disc 10 can be removed

[0027] One skilled in the art will understand that components of embodiments of this disclosure can be formed from any materials suitable for the purposes of this disclosure and attached or otherwise joined according to any attachment mechanisms suitable for the purposes of this disclosure. In addition, disc 10 (or other-shaped cutting member) can be scaled in size to conform to any design diameter of RIs/VCCs.

[0028] Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.