Helical Screw Pile and Soil Displacement Device with Curved Blades

• US 20150117960A1
• Filed: 10/25/2013
• Published: 04/30/2015
• Est. Priority Date: 10/25/2013
• Status: Active Grant

• Current Assignee: Hubbell, Inc.
• Original Assignee: Hubbell, Inc.
• Inventors: KEMP, Timothy Michael, DOWNEY, Shawn David, HAWKINS, Kelly Suzanne
• Granted Patent: US 9,416,513 B2
• Time in Patent Office: Days
• US Class Current: 405/252.1
• CPC Class Codes: E02D 5/56 Screw piles placing piles by screwing down E02D7/22
• CPC Class Codes: E02D 5/72 Pile shoes
• CPC Class Codes: E02D 5/801 driven by screwing
• CPC Class Codes: E21B 7/26 Drilling without earth removal, e.g. with self-propelled burrowing devices E21B7/30 takes precedence

Abstract

A helical screw pile having a soil displacement device (lead displacement plate) on its shaft above at least one helical plate, which pulls the pile into the ground when the shaft is rotated. The lead displacement plate has a disk that carries at least two curved, axially extending bottom blades, which preferably extend beyond the disk periphery. The axial height of the blades preferably is greater than the axial pitch of the helical plate(s) divided by the number of blades. The top of the disk has an axially extending adapter ring that defines an annular seat for centering a tubular casing. Extension displacement plates can be used between extension shafts for centering additional tubular casings.

Claims

1. A soil displacement device for penetrating and forming a void in the ground when rotated about a central longitudinal axis by a helix-bearing shaft, the device comprising:

a disk having a periphery, a top, a bottom and a central through-opening for receiving a shaft; and

at least two blades disposed substantially completely below the top of the disk, each blade projecting substantially axially from said bottom to a free distal edge and curving outward from near said opening to at least said periphery.

2. The soil displacement device of claim 1, wherein the radius of curvature of each blade is non-uniform.

3. The soil displacement device of claim 2, wherein the radius of curvature of each blade is larger near the opening and near the disk periphery than its radius of curvature in an intermediate portion therebetween.

4. The soil displacement device of claim 3, wherein the blades extend beyond the disk periphery.

5. The soil displacement device of claim 4, wherein a portion of each blade beyond the disk periphery is substantially normal to a radius of the disk.

6. The soil displacement device of claim 5, wherein each blade tapers toward its distal edge.

7. The soil displacement device of claim 6, wherein each blade has a convex face and a concave face, and wherein the taper of each blade is formed by a slope of said concave face.

8. The soil displacement device of claim 6, wherein the bottom of the disk tapers toward its periphery.

9. The soil displacement device of claim 1, wherein the blades extend beyond the disk periphery.

10. The soil displacement device of claim 1, wherein each blade tapers toward its distal edge.

11. The soil displacement device of claim 10, wherein each blade has a convex face and a concave face, and wherein the taper of each blade is formed by a slope of said concave face.

12. The soil displacement device of claim 1, wherein the bottom of the disk tapers toward its periphery.

13. The soil displacement device of claim 1, wherein the distal edges of the blades are substantially coplanar and substantially normal to said axis.

14. The soil displacement device of claim 1, further comprising an adapter ring extending axially from the top of the disk inboard of the disk periphery and defining an annular seat on the disk for centering a tubular casing.

15. The soil displacement device of claim 14, wherein the adapter ring has an outer face that tapers toward a distal end thereof.

16. A helical screw pile for penetrating the ground and forming a support, the screw pile comprising:

a shaft having a longitudinal axis and a bottom end;

at least one helical plate on said shaft near said bottom end; and

a soil displacement device on said shaft above said at least one helical plate, the soil displacement device including;

a disk having a periphery, a top, a bottom and a central opening through which the shaft extends; and

at least two blades disposed substantially completely below the top of the disk, each blade projecting substantially axially from said bottom to a free distal edge and curving outward from near said opening to at least said periphery.

17. The helical screw pile of claim 16, wherein each blade has an axial height that is greater than the axial pitch of said at least one helical plate divided by the number of blades.

18. The helical screw pile of claim 16, wherein the blades extend beyond the disk periphery.

19. The soil displacement device of claim 16, wherein the distal edges of the blades are substantially coplanar and substantially normal to said axis.

20. The helical screw pile of claim 16, wherein the soil displacement device has an adapter ring extending axially from the top of the disk inboard of the disk periphery and defining an annular seat on the disk for supporting and centering a tubular casing surrounding the shaft.

21. The helical screw pile of claim 20, wherein the shaft includes a plurality of sequentially connected shaft segments including a lead shaft at the bottom and extension shafts thereabove, wherein the at least one helical plate is carried by the lead shaft and the soil displacement device is carried by either the lead shaft or one of the extension shafts, further comprising at least one extension displacement plate carried by the shaft above the soil displacement device, the extension displacement plate having oppositely facing annular seats for centering tubular casings surrounding the shaft.

22. The helical screw pile of claim 16, wherein the central opening and the shaft are substantially square, further comprising a substantially square insert in the central opening having a substantially square aperture sized to closely receive the shaft.