US3808821A

US3808821A - Self-powered casing for forming cast-in-place piles

Info

Publication number: US3808821A
Application number: US00289705A
Authority: US
Inventors: K Philo
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-15
Filing date: 1972-09-15
Publication date: 1974-05-07
Anticipated expiration: 1991-05-07
Also published as: CA979676A

Abstract

A self-powered casing for forming cast-in-place piles in the earth surface. A casing formed of a central cylindric tube and an outer segment casing. The outer segmented casing is tangential of the tube so that the casing can be placed by drilling. Actuators for longitudinally driving the individual segments of the outer casing with respect to the central tube. A casing capable of forming piles of virtually any cross-sectional shape.

Description

United States Patent [191 Philo' SELF-POWERED CASING FOR FORMING CAST-IN-PLACE PlLES [76] Inventor: Kenneth W. Philo, 7 Palm Ave., San

' Rafael, Calif. 94118 [22] Filed: Sept. 15, 1972 21 Appl. No.: 289,705

[52] US. Cl 6l/53.64, 6l/53.7, 61/63 [51] Int. Cl E02d 5/38 [58] Field of Search 6l/53.64, 53.66, 53.7,

[5 6] References Cited UNITED STATES PATENTS 3,344,611 l0/l967 Philo 6l/53.64

[ 11 3,808,821 [451 May 7,1974

Primary Examiner--Jacob Shapiro Attorney, Agent, or Firm-Townsend and Townsend [5 7] ABSTRACT A self-powered casing for forming cast-in-place piles in the earth surface. A casing formed of a central cylindric tube and an outer segment casing. The outer segmented casing is tangential of the tube so that the casing can be placed by drilling. Actuators for longitudinally driving the individual segments of the outer casing with respect to the central tube. A casing capable of forming piles of virtually any cross-sectional shape.

ll Claims, 11 Drawing Figures minimum 1 m4 18081821 saw 1 0F 2 FIG 2 FIG 4 SELF-POWERED CASING FOR FORMING CAST-IN-PLACE PILES This invention relates to a casing for forming concrete piles in the earth and more particularly to such casing that can be placed in the ground by drilling and can be raised and lowered with respect to the ground surface by power units contained within the structure itself. Accordingly high-powered hoisting and/or piledriving equipment is not required in forming concrete piles according to the present invention.

In my U.S. Pat. No. 3,344,61 l I disclose a pileforming mandrel or casing that has significant advantages over any known prior art structures. The mandrel described and claimed in such patent is placed at a suitable depth in the earth surface by conventional piledriving equipment,- and on construction sites where the noise and vibration of pile-driving procedures is acceptable such mandrel is most satisfactory.

In certain construction sites, e.g., those in residential districts where excessive noises are not acceptable or in sites adjacent to existing structures, it is preferable to introduce the casing mandrel by drilling or augering techniques which are quieter and produce less vibration than pile-driving techniques. The present invention provides a casing that is introduced into the earth s surface in conjunction with a soil auger. Such mode of operation is afforded because the present invention includes a centrally positioned cylindric tube the interior opening of which is totally unrestricted so as to receive a conventional soil auger therethrough. Without the tube'is a segmented casing and means for longitudinally driving the segments of the casing with respect to the central cylindrical tube. Such driving means are located without the tube so as not to interefere with the auger.

Another advantage of a casing according to the present invention is that it can be adapted to form piles of virtually any cross-section configuration. Achievement of this object is possible because the outer segments can be individually powered as the auger drills into the earth s surface so that earth residing outside a perfectly circular hole can be shaved or dislodged as the casing follows the auger into the earth. Because the casing is self-powered, the outer casing portions thereof can be forced to move down so as to cut out the comers between the circular hole drilled by the auger and the exterior shape of the segmented outer casing covering which dictates the shape of the hole.

Other objects, features, and advantages of the present invention will become more apparent after referring to the following specification and accompanying drawings in which:

FIG. 1 is a plan view of a casing according to the present invention as it appears during placement in the earths surface;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is an elevation view of a casing according to this invention in place preparatory to the introduction of concrete thereinto;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a detailed view at enlarged scale of a portion of the casing of FIG. 4;

FIG. 6 is an elevation view of the casing during placement of concrete at one position of operation;

FIG. 7 is an elevation view of the casing according to this invention at another position during placement of concrete;

FIG. 8 is an elevation view of an alternate embodiment of the present invention;

FIG. 9 is a fragmentary view of a portion of FIG. 8 at an enlarged scale;

FIG. 10 is a c cross-sectional taken along line l0l0 of FIG. 8; and

FIG. 11 is a cross-sectional view taken along line lll1 of FIG. 8.

Referring more particularly to the drawings and specifically to FIGS. 1-7, reference numeral 12 indicates one embodiment of the casing according to the present invention. Casing 12 includes a central cylindric rigid tube 14 which defines a cylindric opening to admit an anger l6 therethrough. Carried exterior of tubular member 14 is an outer casing composed of four segments identified by

reference numerals

16a, 16b, 16c, and 16d. The segments are longitudinally slidable with respect to one another and with respect to central tube 14. For so mounting the segments, reference is made to FIG. 5 wherein a threaded stud l8 protrudes from the outer surface of central tube 14 between the edges of adjacent segments. A joint cover plate 20 is provided with appropriately spaced apart holes to fit over the respective studs 18. A nut 22 is threaded on the outer end of threaded stud 18 to retain joint plate 20 in place. As can be seen in FIGS. 2 and 4, the circumferential extent of each of the segments l6a-16d is such that their edges are spaced apart by an amount sufficient to accommodate stud 18 but are sufficiently close that they slide under joint plate 20.

For driving each individual segment l6a-l6d longitudinally with respect to central tube 14 there are provided at one top of the apparatus a plurality of hydraulic cylinders, one of which is associated with each of the segments. Associated with segment'l6a is a double-acting hydraulic cylinder 24a, associated with segment 16b is a hydraulic cylinder 24b, associated with segment is a hydraulic cylinder 24c and associated with segment 16d is a hydraulic cylinder 24d.

Hydraulic actuators 24a-24d each include a cylinder and a piston and rod. For example, as seen in FIG. 1, actuator 240 includes a cylinder 26c which is attached to casing segment 16c at 280. The actuator also includes a piston and rod assembly 300 which is attached to central tube 14 at 32c. Opposite ends the cylinder 260 are supplied with pressurized hydraulic fluid through conventional fittings (not shown) so that the actuators are double acting. Moreover, each actuator is separately controllable by conventional valving mechanism (not shown).

The operation of this embodiment of the invention can be appreciated by reference to FIGS. 1, 3, 6, and 7. The casing 12 is placed in an upright position on the earth surface and auger 16 is introduced centrally of central tube 14. Hydraulic actuators 24a-24d are maintained in a retracted position as shown in FIG. 1 so that the lower extremity of easing segments 16a16d will coincide with the lower extremity of central tube 14. The diameter of the flights on auger 16 are approximately the same as the inner diameter of central tube 14 so that as the auger is rotatively driven in a conventional manner the loose earth is drawn upward within the central tube.

Because of the mass of the entire casing structure, the periphery of the hole formed by the auger is shaved off so that in many locations the casing follows the auger downward by force of gravity. In certain locations in which the soil is extremely wet or dense and particularly when a substantial portion of the casing is below the surface of the earth and therefore in contact with the walls of the hole, the force of gravity may be insufficient to cause the casing to follow the auger downward. In such a situation the casing can be caused to move downward by sequentially actuating hydraulic actuators 24a-24d so as to move one segment of the casing down at a time. For example and in reference to FIG. 1, hydraulic actuator 24c can be activated by supplying hydraulic fluid under pressure to the lower end of cylinder 260 which will drive segment 16c downward with respect to central tube 14 and with respect to the other three segments. Such is the case because the force of the skin friction on the other three segments plus the force of gravity on the entire casing exceeds the skin friction that tends to resist the downward movement of segment 160. The other hydraulic actua tors can then be actuated in sequence to move the entire casing downward so that it follows the auger even in adverse circumstances where the skin friction between the wall of the hole and the outer segments is great. When the casing reaches the desired depth, FIG. 3, the auger is removed and reinforcing steel 34 can be placed down into central tube 14 if desired. Thereafter, concrete is deposited into the top of central tube 14. Because of the large diameter the inner opening of tube 14, vibrating apparatus, if desired, can be lowered into the hole so that the concrete is uniformly distributed throughout the reinforcing steel 34. As the level of the concrete raises, FIG. 6, actuators 24a-24d are actuated in unison to the extended position shown in FIG. 6. In consequence of such action central tube 14 is raised. It is preferable that this step be performed when the level of the concrete is at about the same level as the lower extremity of the inner tube 14. Thereafter the segments can be raised either in pairs or singly, depending upon the frictional resistance between the outer surface of the segments and the soil bearing against such outer segments, e.g., 16b, can be raised, and. the reactive force to permit such raising arises from the force of the friction of the soil on the other stationary casing segments. After all actuators have been retracted additional concrete is introduced and the central tube is then raised. After the inner tube is raised to a position equivalent to that of FIG. 6, the segments are raised individually or in pairs-and such procedure is repeated until the casing is free of the ground surface at which time the pile iscomplete and the casing can be removed to another construction site.

An alternate embodiment of the presentinvention is shown in FIGS. 9-11. Such alternate embodiment is adapted to form square piles which are particularly useful as solder beams in forming retaining walls and the like. Such alternate embodiment includes a central cylindric tube 40 on the exterior surface of which are four

outer casing segments

42a, 42b, 42c, and 42d. As seen a to the travel of the actuator. Thereafter, subsequent in FIG. 11 such segments are formed of mutually perpendicular plates which approach the outer circumferential surface of the central cylindric tube in a tangential manner.

For supporting the outer casing segments for longitudinal movement with respect to the central tube, a cylindric rod 44 is fastened to the exterior surface of the tube and on the concave side of each outer casing segment 42a42d are secured a plurality of spaced-apart guide members 46. As seen in FIG. 11, guide members 46 are of circular form complementary to the outer surface of cylindric rod 44 and have a circumferential extent in excess of 180 so that the casing members are constrained for verticle movement with respect to central cylindric tube 40. As seen in FIG. I l, the four outer casing members"42a42d are in quadrature or are spaced from one another by around the central cylindric tube.

Each outer casing segment 42a-42d is provided with means for driving it longitudinally with respect to the central tube. For this purpose four hydraulic cylinders are provided: cylinder 48a being fastened to outer casing segment 42a, hydraulic cylinder 48b being fastened at 50 to outer casing segment 42b, hydraulic cylinder 480 being fastened at 51 ,to outer casing segment 42c, and hydraulic 48d being fastened to outer casing segment 42d. Each actuator is provided with a piston and rod assembly 52, the outer end of which is fastened to central cylindric tube 40 at 54 (see FIG. 9). Cylinders 48a-48d are double acting and conventional hydraulic fittings (not shown) are connected to opposite ends of the cylinder so that the piston and rod 52 can be driven in either direction with respect to cylinders 48a-48d.

The operation of this embodiment of the invention is substantially the same as that directed hereinabove with respect to FIGS. 1-7. As the auger within the central opening of central cylindric tube 40 drills the earth, the casing moves downward by the force of gravity during which time the corners of the opening are shaved off by the lower ends of the outer casing segments 42a-42d. Should the force of gravity be insufficient to overcome the skin friction on the outer surface of the casing, the outer casing segments can be moved down either individually or in pairs. For example, hydraulic cylinder 48a can be extended to move outer casing segment 42a downward while the remaining casing segments 42b-42d remain stationary. The amount of the area of the outer surface of central cylindric tube 40 that is exposed to the earth is, as can be seen in FIG. 11 minimal since the plates of the outer casing segments approach the surface tangentially and virtually cover the entire outer surface of the central tube. Thus the embodiment of the invention of FIGS. 9-11 is capable of being self-powered downward as the auger removes the central core of dirt, and the comers of the lower edges of the outer casing segments 42a42d shave off the corners of the hole. When the casing is in place, the auger is removed and concrete is introduced centrally of central cylindric tube as disclosed in the above described embodiment. Reinforcing steel, of course, can be first placed within the opening of central cylindric tube 40. As the concrete is poured the casing is lifted by sequential activation of hydraulic cylinders 48a-48d in a manner identical to that disclosed hereinabove. v

The square configuration of the apparatus of FIGS. 9-11 is but exemplary of many possible shapes. For example, three casing segments, the plates of which detine an included angle of 60 can be employed to form- Moreover, the plates that form the segments preferably approach the outer surface of the central cylindric tube in a tangential manner so that the amount of earth that is shaved off by the segments is reduced to a minimum.

Thus it will be seen that the present invention provides a mandrel or casing that can be positioned into the earth by drilling and without necessity for pile driving equipment. The casing can be inserted in virtually any type soil irrespective of the amount of skin friction imposed by the soil on the walls of the casing since the casing can be moved one segment at a time. The advantage of this, of course, is that the stationary segments a are maintained stationary by skin friction and provide a sufficient reactive force to enable one or more outer casing segments to be moved.

Although two embodiments of the invention have been shown and described, it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is;

l. A self powered casing for forming cast-in-place concrete piles comprising a cylindric rigid tube defining a central opening for admitting a soil auger, a segmented outer casing covering a major portion of the exterior of said tube, said outer casing being formed of a plurality of segments arranged to slide longitudinally of the tube and of one another, and an equal plurality of means for longitudinally moving each segment with respect to said tube, said segment moving means being at least in part disposed exterior of said casing to afford unrestricted introduction of a soil auger in said opening.

2. A casing according to claim 1 wherein said outer casing segments define a cylinder having an inner surface substantially coextensive with the exterior surface of said cylindric rigid tube so as to minimize the amount of soil shaved by movement of said outer casing during downward movement thereof.

3. A casing according to claim 2 wherein said segments are of equal arcuate extent and wherein the longitudinally extending edges of adjacent segments are spaced apart from one another, said casing including a joint cover plate spanning the space between said segments and means for attaching said joint cover plate to said rigid tube.

4. A casing according to claim 1 wherein said segmented outer casing comprises a plurality of segments formed from pairs of rigidly joined angularly oriented 6 plates, said plates being disposed tangentially to the outer surface of said tube, the totality of said plates covering a major portion of the exterior surface of said tube. I

5. A casing according to claim 4 wherein the plates of each said segment define a right angle and wherein there are four such segments uniformly spaced around said tube so that a square pile can be formed by said casing.

6. A casing according to claim 4 including means for constraining said segments for movement longitudinal of said tube, said constraining means being disposed on the concave side of said segments intermediate said segments on the outer surface of said tube.

7. A casing according to claim 6 wherein said constraining means includes' a continuous elongate member fastened to said tube and a plurality of guide members mounted on the concave side of said segments and slidably embracing said elongate member.

8. A casing according to claim 1 wherein said segment moving means comprises a hydraulic actuator having a cylinder member and a piston member moveable in said cylinder member, means for attaching one of said members to the upper end of said tube and means for attaching the other said member to the upper end of said segment so that the balance of the exterior surface of said casing is unobstructed to afford entry thereof into a drilled hole.

9. A casing for constructing underground piles comprising a rigid inner tube defining a central passage communicating a lower end of the tube with an upper end thereof; a segmented outer casing covering at least a portion of the exterior of the tube, the outer casing having a plurality of segments arranged to slide longitudinally of the tube and of one another;vand an equal plurality of means for longitudinally moving each segment with respect to the tube, the segment moving means being at least in part disposed exterior of the outer casing so as to not restrict a cross-section of the passage way.

10. A casing for constructing underground piles comprising a rigid tubular member defining an unobstructed passage over the length of the member, the member including a continuous convex exterior side; a segmented outer casing covering a major portion of the exterior side of the member and being formed of a plurality of segments arranged to move longitudinally with respect to each other; and means for independently longitudinally moving each of the segments with respect to the member, the segment moving means being wholly disposed on the convex side of the member so as to not restrict the central passage.

11. A casing according to claim 10 wherein the tubular member has a cylindrical configuration.

Claims

1. A self powered casing for forming cast-in-place concrete piles comprising a cylindric rigid tube defining a central opening for admitting a soil auger, a segmented outer casing covering a major portion of the exterior of said tube, said outer casing being formed of a plurality of segments arranged to slide longitudinally of the tube and of one another, and an equal plurality of means for longitudinally moving each segment with respect to said tube, said segment moving means being at least in part disposed exterior of said casing to afford unrestricted introduction of a soil auger in said opening.

4. A casing according to claim 1 wherein said segmented outer casing comprises a plurality of segments formed from pairs of rigidly joined angularly oriented plates, said plates being disposed tangentially to the outer surface of said tube, the totality of said plates covering a major portion of the exterior surface of said tube.

7. A casing according to claim 6 wherein said constraining means includes a continuous elongate member fastened to said tube and a plurality of guide members mounted on the concave side of said segments and slidably embracing said elongate member.

9. A casing for constructing underground piles comprising a rigid inner tube defining a central passage communicating a lower end of the tube with an upper end thereof; a segmented outer casing covering at least a portion of the exterior of the tube, the outer casing having a plurality of segments arranged to slide longitudinally of the tube and of one another; and an equal plurality of means for longitudinally moving each segment with respect to the tube, the segment moving means being at least in part disposed exterior of the outer casing so as to not restrict a cross-section of the passage way.