US3785759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Machine for forming a continuous seamless concrete pipe
Assignee: Individual
•
Filing: 1972-01-24
•
Granted: 1974-01-15
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Expires: 1992-01-24
Abstract
Abstract A continuous seamless pipe is formed in a trench from a cementitious mix by advancing through the trench a carriage mounting a trailing cylindrical drum with its axis parallel to the direction line of carriage movement and a diameter equal to the internal pipe diameter, and a cylindrical skirt having a diameter approximating the outer pipe diameter concentrically surrounding the drum to define an intervening rearwardly opening annular cylindrical containing an annular piston. The cementitious mix is fed into the front end of the cylinder and the piston is driven rearwardly through the cylinder to extrude the mix through the open rear end of the cylinder to form the pipe wall and exert a forward reaction force on the carriage for propelling the latter through the trench. The plunger may be segmented to obtain more uniform extrusion about the full cylinder circumference. The drum may be driven in rotary or other motion, and the drum, plunger and/or skirt may be vibrated to compact the extruding mix. A rotary trowel on the rear end of the drum smooths the inner surface of the extruded pipe. The preferred cementitious mix is a low slump concrete which may be extruded to form a seamless concrete pipe without the need to internally support the pipe.
Inventors
- 👤 R Midthun
- 👤 B Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:11
CPC Classifications
F; F16; F16L; F16L1/00; F16L1/024; F16L1/028; F16L1/038; F16L1/032
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
236 words
A machine for forming a continuous seamless cementitious pipe within a trench, comprising: a carriage movable forwardly through said trench, a cylindrical drum at the rear of said carriage having its axis parallel to the direction line of carriage movement, said drum having a diameter approximating the internal diameter of said pipe and a cylindrical length which is a major portion of the overall length of the drum means for driving said drum in a motion which does not alter the position of the drum axis relative to said carriage, a cylindrical skirt about and concentric with said drum and having a diameter approximating the outer diameter of said pipe, said drum and skirt defining an intervening rearwardly opening annular cylinder about the drum having a radial dimension approximating the wall thickness of said pipe, means for feeding a cementitious mix into the forward end of said cylinder, and means for feeding said mix rearwardly through and extruding the mix through the rear end of said cylinder during said motion of said drum to form the pipe wall between the drum and the trench walls as the machine moves forwardly through said trench, said feeding means comprising annular plunger means movable axially through and having a radial dimension approximating that of said cylinder, and fluid power actuator means connected between said carriage and plunger meaNs for driving said plunger means back and forth through said cylinder.
Claim 2
Dependent Claim
236 words
A machine for forming a continuous seamless cementitious pipe within a trench, comprising: a carriage movable forwardly through said trench, a cylindrical drum at the rear of said carriage having its axis parallel to the direction line of carriage movement, said drum having a diameter approximating the internal diameter of said pipe and a cylindrical length which is a major portion of the overall length of the drum means for driving said drum in a motion which does not alter the position of the drum axis relative to said carriage, a cylindrical skirt about and concentric with said drum and having a diameter approximating the outer diameter of said pipe, said drum and skirt defining an intervening rearwardly opening annular cylinder about the drum having a radial dimension approximating the wall thickness of said pipe, means for feeding a cementitious mix into the forward end of said cylinder, and means for feeding said mix rearwardly through and extruding the mix through the rear end of said cylinder during said motion of said drum to form the pipe wall between the drum and the trench walls as the machine moves forwardly through said trench, said feeding means comprising annular plunger means movable axially through and having a radial dimension approximating that of said cylinder, and fluid power actuator means connected between said carriage and plunger meaNs for driving said plunger means back and forth through said cylinder.
Claim 3
Dependent Claim
15 words
A pipe forming machine according to claim 1 including: vibrator means for vibrating said skirt.
Claim 4
Dependent Claim
33 words
A pipe forming machine according to claim 1 wherein: said skirt has openings at the forward end of said drum through which said cementitious mix may flow to the exterior of the skirt.
Claim 5
Dependent Claim
35 words
A pipe forming machine according to claim 1 wherein: said plunger means comprises a number of independently movable segments, and said actuator means comprises independent actuators for driving said plunger segments independently through said cylinder.
Claim 6
Dependent Claim
41 words
A pipe forming machine according to claim 1 including: paddles on the front end of said drum which rotates with said drum to agitate said mix entering the forward end of said cylinder and distribute the mix uniformly about said cylinder.
Claim 7
Dependent Claim
55 words
A pipe forming machine according to claim 1 wherein: said carriage includes a rear section mounting said drum, skirt, plunger means and actuator means, and a front section, means on said front section for driving said carriage through said trench, and pivotal coupling means joining said carriage sections for relative lateral pivoting of said sections.
Claim 8
Dependent Claim
21 words
A pipe forming machine according to claim 6 wherein: said coupling means are disengageable to permit separation of said carriage sections.
Claim 9
Dependent Claim
48 words
A pipe forming machine according to claim 1 including: means for driving said drum in rotation, a rotary trowel concentrically mounted at the rear end of and having the same outer diameter as said drum, and means for driving said trowel in rotation independently of said drum motion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |