Soil displacing screw auger and method for making a concrete pile with this auger

• US 6,283,231 B1
• Filed: 12/03/1997
• Issued: 09/04/2001
• Est. Priority Date: 12/03/1996
• Status: Expired due to Term

• Current Assignee: Morris-Shea Bridge Company Incorporated
• Original Assignee: Morris-Shea Bridge Company Incorporated
• Inventors: Coelus, Gaspar Jozef
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): KRECK, JOHN J
• Application Number:
  US08/984,471
• Time in Patent Office: 1,371 Days
• Field of Search: 405/242, 405/240, 405/241, 405/233, 175/323, 175/325.1, 175/325.5, 175/388, 175/391, 175/394, 175/22
• US Class Current: 175/323
• CPC Class Codes: E02D 5/36 making without use of mouldpipes or other moulds
• CPC Class Codes: E02D 5/56 Screw piles placing piles by screwing down E02D7/22
• CPC Class Codes: E02D 7/22 Placing by screwing down screw piles per se E02D5/56
• CPC Class Codes: E21B 10/44 Bits with helical conveying portion, e.g. screw type bits; Augers with leading portion or with detachable parts E21B10/42 takes precedence

Abstract

Soil-displacing screw auger which contains an auger tube (1); a double displacement body (2) equipped with a hollow shaft (8) fixed to the auger tube (1) and containing an upper part (6) which constitutes a closed screw the radius of which increases towards its lower extremity and a lower part (7) which constitutes a closed screw the radius of which decreases towards its lower extremity, preferably with the same pitch as the upper part (6); a lower tube the diameter of which is smaller than twice the largest radius (R2) of the displacement body and which is situated between the lower part (7) of the displacement body (2) and the lower extremity of the auger; a screw blade (4) welded onto the outer casing of the lower tube, which rotates in the same sense as the lower part (7) of the displacement body (2) and an auger tip (5) connected to the lower extremity of the lower tube, with the special characteristic that the lower tube of the auger is an intermediate tube (3) with an outer diameter (D3) which is smaller than twice the largest radius (R2) of the displacement body (2) but larger than the outer diameter (D1) of the auger tube (1), whereas the auger tip (5) contains a displacement part (16) with a closed screw rotating in the same sense as the screw blade (4) on the intermediate tube (3) and a maximal radius equalling half the diameter (D3) of the intermediate tube (3).

Claims

1. In a Soil-displacing screw auger which contains an auger tube (1);

a double displacement body (2) equipped with a hollow shaft (8) fixed to the auger tube (1) and containing an upper part (6) which constitutes a closed screw the radius of which increases spirally towards the lower extremity and a lower part (7) which constitutes a closed screw the radius of which decreases spirally towards its lower extremity, with substantially the same pitch as the upper part (6);

a lower tube, the diameter of which is smaller than twice the largest radius (R2) of the displacement body (2) and which is situated between the lower part (7) of the displacement body (2) and the lower extremity of the auger;

a screw blade (4) welded onto the outer casing of the lower tube, which rotates in the same sense as the lower part (7) of the displacement body (2) and an auger tip (5) connected to the lower extremity of the lower tube, the improvement comprising;

the lower tube of the auger is an intermediate tube (3) with an outer diameter (D3) which is smaller than twice the largest radius (R2) of the displacement body (2) but larger than the outer diameter (D1) of the auger tube (1), whereas the auger tip (5) contains a displacement part (16) with a closed screw rotating in the same sense as the screw blade (4) on the intermediate tube (3) and a maximal radius equalling half the diameter (D3) of the intermediate tube (3).

2. Screw auger in accordance with claim 1, with the special characteristic that the screw blade (4) has an outer diameter (D2) which substantially equals twice the above-mentioned largest radius (R2) of the displacement body (2).

3. Screw auger in accordance with claim 2, with the special characteristic that the closed spiral of the displacement part (16) of the auger tip (5) has a smaller pitch (S5) than pitch (S4) of the screw blade (4) on the intermediate tube (3).

4. Screw auger in accordance with claim 3,

with the special characteristic that the pitch (S4) of screw blade (4) on intermediate tube (3) equals the pitch (S2) of the screws of the two parts (6 and 7) of the displacement body (2).

5. Screw auger in accordance with claim 4, with the special characteristic that the pitch (S2) of the displacement body (2) and the pitch (S4) of screw blade (4) on the intermediate tube (3) are equal and to S5×

D4²/(D4²−

D3²), in which S5 is the pitch of the displacement part (16) of auger tip (5), D4 is the outer diameter of the above-mentioned screw blade (4) and D3 is the outer diameter of intermediate tube (3).

6. Screw auger in accordance with claim 5,

with the special characteristic that one extremity of the auger tip (5) is a detachable close-off tip (17) which will be left behind in the ground (20) as a lost tip.

7. Screw auger in accordance with claim 6, with the special characteristic that this close-off tip (17) is a displacement body itself and has a closed screw on the outside with the same pitch as the displacement part (16) of the auger tip (5) and with a radius which increases towards this displacement part (16).

8. Screw auger in accordance with claim 7,

with the special characteristic that the auger tip (5) can be exchanged and is connected to the intermediate tube (3) by means of a coupling.

9. Screw auger in accordance with claim 8,

with the special characteristics that the auger tip (5) has a cylindrical part at the top, above the displacement part (16), the diameter (D14) of which corresponds to the diameter (D3) of the intermediate tube (3) and a screw blade (15) on this cylindrical part (14) with the same diameter and sense of rotation as screw blade (4) on intermediate tube (3) and preferably with the same pitch.

10. Screw auger in accordance with claim 9,

with the special characteristic that the intermediate tube (3) has a hollow shaft (8) for the concrete, formed by part of the auger tube (1) extending through the intermediate tube (3) until or into the displacement part (16) of auger tip (5).

11. Screw auger in accordance with claim 10,

with the special characteristic that the pitch (S5) of the displacement part (16) of the auger tip (5) has a value between 5 and 7.5 cm.

12. Screw auger in accordance with claim 11,

with the special characteristic that the outer diameter (D3) of the auger tube (3) has a value between D2/1.3 and D2/1.17, in which D2 is twice the maximum radius R2 of the displacement body (2).