Geotechnical Apparatus Roller Straightening
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Solution Overview
Problem
Existing geotechnical apparatuses for investigating soil penetration resistance are hindered by complex drive systems with many moving parts, leading to insufficient rod straightness and coil diameter consistency, high contact forces causing deformation, and increased complexity, particularly when operating on the sea floor.
Innovation Solution
A geotechnical apparatus with a bending/straightening device using sets of rollers to convert coiled rods to straight and then back to constant diameter coils, and a drive unit with grippers for linear movement, reducing the need for high tensile forces and minimizing contact pressure, utilizing hydraulic movements and adjustable rollers for versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex drive system with many moving parts is used, then the rod can be pushed and pulled, but the system becomes unreliable due to sealing requirements and high contact forces causing deformation
Solution Approach 1:
The patent removes the complex injector heads with multiple moving parts and sealing requirements from the system. Instead, it uses a simple reel for uncoiling and a bending/straightening device with rollers for straightening, eliminating the need for complex sealing mechanisms while maintaining the core functionality of pushing and pulling the rod
Solution Approach 2:
Instead of using a complex injector head to push the rod, the patent uses a simple reel to uncoil the rod and a bending/straightening device to straighten it. The pushing function is achieved by the weight of the rod itself and the friction from the rollers, inverting the traditional approach where a complex mechanism provides the pushing force
2Ease of manufacture
If the rod is pulled along a goose neck to uncoil it, then the uncoiling operation is simple, but the rod does not achieve sufficient straightness for geotechnical investigations
Solution Approach 1:
The patent introduces a bending/straightening device with rollers as an intermediary between the reel and the ground. This device receives the coiled rod from the reel and progressively straightens it using multiple rollers that apply controlled bending forces, achieving the required straightness without complicating the uncoiling process
Solution Approach 2:
The straightening process is divided into multiple stages using several rollers arranged in sequence. Each roller or pair of rollers applies a small bending correction, and the cumulative effect of these segmented corrections achieves the required straightness without requiring a single complex straightening mechanism
3Force
If a high point contact force is applied during pushing and pulling, then sufficient friction is obtained to drive the rod, but the rod undergoes cold deformation to a smaller diameter
Solution Approach 1:
The patent transitions from point contact (injector head) to line contact (rollers). The rollers contact the rod along a line rather than at a single point, distributing the driving force over a larger area. This reduces the contact pressure and prevents cold deformation while maintaining sufficient friction for driving the rod
Solution Approach 2:
The patent changes the contact geometry parameter from point contact to line contact by using rollers. This parameter change increases the contact area and reduces the contact pressure, allowing sufficient friction force to be obtained without applying high point contact forces that would cause cold deformation
4Stability of the object's composition
If additional holding elements are added to the reel to maintain coil diameter, then the coil stability is improved, but the reel complexity increases
Solution Approach 1:
The bending/straightening device with rollers is positioned before the rod is paid out from the reel. This preliminary straightening action ensures that the rod is straightened as it uncoils, preventing the need for additional holding elements on the reel to maintain coil diameter stability
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 solution achieves improved rod straightness and coil diameter consistency with reduced risk of deformation, simplifies the drive unit, and maintains effectiveness in frequent coiling/uncoiling operations, such as those in sea floor geotechnical investigations.
Implementation Method 1
The bending/straightening device is equipped with a first set of rollers of which at least two are positioned at one side of the rod and the remaining rollers form a second set of rollers positioned at an opposing side of the rod, so as to arrange that the rollers are arranged to convert the coiled rod to an essentially straight rod when uncoiling
Implementation Method 2
the rollers are arranged to convert the straight rod to a coiled rod of essentially constant coil diameter when coiling
Implementation Method 3
the drive unit with grippers for linear movement, reducing the need for high tensile forces and minimizing contact pressure
Data Source
Figure 1
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AI summary
Geotechnical apparatus (1) equipped for geotechnical investigation comprising a holder with a coiled rod (3) wherein the rod (3) is provided with a probe (24), such as a pene-trometer, and the apparatus comprises a rod bending/straightening device (4) and a drive unit (14) for both uncoiling the coiled (3) continuous rod (3) and pushing the uncoiled rod (3) with the probe (24) into the ground and for pulling such a rod (3) with the probe (24) out of the ground and recoiling (3) the continuous rod, the apparatus (1) be-ing arranged for operation on land as well as on a sea floor, wherein the drive unit (14) comprises two grippers (15, 17) arranged to alternatingly grip the rod (3) and move it along its longitudinal axis over a predefined length, wherein the bending/straightening device (4) is equipped with a first set of rollers of which at least two (8, 9, 10) are positioned at one side of the rod (3) and the remaining rollers (11, 12) form a second set of rollers positioned at an opposing side of the rod (3), so as to arrange that the rollers (8, 9, 10, 11, 12) are arranged to convert the coiled rod (3) to an essentially straight rod (3) when uncoiling and are arranged to convert the straight rod to a coiled rod (3) of essentially constant coil diameter when coiling.