Spiral Pipe Forming Without Inner Restriction Bodies
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Solution Overview
Problem
Existing pipe-forming apparatuses for spiral pipes have structural enlargement and weight increase due to inner periphery restriction bodies, which can inhibit water flow in rehabilitated pipes, especially in non-circular cross-section pipes, and face challenges in diameter expansion and contraction control.
Innovation Solution
A pipe-forming apparatus that omits the inner periphery restriction body, using a driving part to press the strip member obliquely and a pipe end guide to engage the preceding spiral pipe portion, allowing for propelling and fitting without inner periphery restriction, enabling the formation of spiral pipes on both inner and outer peripheries and accommodating non-circular cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an inner periphery restriction body is provided inside the preceding spiral pipe portion, then the cross section of the spiral pipe is restricted and maintained, but the device structure becomes enlarged and weight increases
Solution Approach 1:
The invention removes the inner periphery restriction body from the pipe-forming apparatus. Instead of using an internal restriction mechanism, the apparatus allows the strip member to be spirally wound and fitted directly against the outer periphery of the preceding spiral pipe portion, eliminating the complex internal structure while maintaining cross-sectional control through the fitting mechanism itself.
2Manufacturing precision
If an inner periphery restriction body is provided inside the rehabilitation pipe, then the cross section is restricted from the inner periphery side, but water flow inhibition occurs
Solution Approach 1:
By removing the inner periphery restriction body, the invention eliminates the obstacle that blocked water flow during construction. The strip member is fitted against the outer periphery of the preceding pipe portion, allowing water to flow freely through the rehabilitation pipe without obstruction from internal restriction structures.
3Manufacturing precision
If an inner periphery restriction body is provided, then the spiral pipe can be formed with controlled cross section, but the apparatus cannot accommodate non-circular cross-sections effectively
Solution Approach 1:
The invention employs a dynamic fitting mechanism where the strip member is elastically deformed and fitted against the outer periphery of the preceding spiral pipe portion. This dynamic fitting process allows the apparatus to adapt to various cross-sectional shapes (circular, oval, irregular) of the existing pipe, maintaining manufacturing precision while achieving high versatility for different pipe geometries.
4Device complexity
If the apparatus configuration is simplified by omitting the inner periphery restriction body, then device complexity is reduced, but control over diameter expansion and contraction becomes challenging
Solution Approach 1:
The invention performs preliminary actions by pre-forming the strip member with fitting portions that will engage with the preceding pipe portion, and pre-positioning the pipe-forming apparatus at the correct location. The strip member is fed and fitted in a controlled manner before final spiral winding, allowing diameter control to be achieved through the fitting mechanism and material properties rather than complex internal restriction structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus simplifies the configuration, mitigates water flow inhibition, and allows for stable pipe formation on non-circular cross-sections without structural enlargement, ensuring effective diameter control and reduced friction during the rehabilitation process.
Implementation Method 1
a driving part pressing the following strip portion following the preceding spiral pipe portion obliquely with respect to a machine-height direction toward a partial part in a circumferential direction of a pipe end portion
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4~5
AI summary
Provided is a pipe-forming apparatus with which a spiral pipe can be formed using a simple configuration without an inner periphery restriction body. A driving part 10 of a pipe-forming apparatus 3 presses a following strip portion 92 toward a pipe end portion 91e of a preceding spiral pipe portion 91 obliquely with respect to a machine-height direction HD. A pipe end guide 20 is constrained in a machine-width direction WD with respect to the pipe end portion 91e, and slidably engaged in a propelling longitudinal direction LD. A pressing force for the following strip portion 92 provides a fitting force between the following strip portion 92 and the pipe end portion 91e, and a propelling force for forward propulsion. A pipe is formed in a state where a part other than a partial part at which the pipe-forming apparatus 3 is provided in a circumferential direction of the pipe end portion 91e is released from the pipe-forming apparatus 3.