Encoder Assembly for Pile Depth Measurement
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Solution Overview
Problem
Existing pile installation monitoring systems, such as those described in Likins U.S. Pat. No. 5,978,749, face issues with accuracy due to deformation of support rods, wire deflection, changing wire tension, and angle variations, leading to errors in depth measurement, especially as pile length increases, and are hindered by the need for rig modifications and susceptibility to tangling and harsh environmental conditions.
Innovation Solution
A measurement device is directly mounted to the load box or hammer cage of a pile installation machine, using an encoder assembly with a roller wheel that engages the rig's structural components, eliminating the need for supporting wires and accounting for movement through rotational data, with optional dual encoder assemblies for redundancy and wireless communication for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-roller system with linear bearing is used to support the wire during unwinding, then lateral movement of the wire is handled effectively, but the support rod deforms or fails under changing load conditions, adversely affecting measurement accuracy
Solution Approach 1:
The invention extracts the measurement function from the wire support system. Instead of measuring wire displacement (which is affected by lateral movement and load changes), the patent uses a separate encoder wheel that directly measures the rotation of the drum or reel, eliminating the need for a complex three-roller support system with linear bearings.
Solution Approach 2:
The encoder wheel acts as an intermediary between the drum rotation and the measurement system. It converts rotational motion directly into measurable data without requiring the wire to pass through a complex mechanical support system, thereby eliminating the deformation and failure issues of the support rod.
2Ease of operation
If the wire is pinched between three rollers with the encoder wheel centered, then the wire can pass through the system, but the wire arcs around the encoder wheel creating measurement errors that change with wire tension
Solution Approach 1:
The invention extracts the measurement function from the wire itself and places it on the drum or reel. The encoder wheel measures drum rotation directly, eliminating the need for the wire to arc around the encoder and the associated measurement errors caused by changing wire tension.
3Reliability
If the measurement system is mounted on the rig boom structure, then depth monitoring can be implemented, but welding modifications to the boom structure is difficult or impossible to obtain approval for
Solution Approach 1:
The invention segments the measurement system into a self-contained unit that can be attached to existing rig components without permanent modifications. The encoder wheel and support bracket form a modular assembly that can be installed and removed without welding to the boom structure.
Solution Approach 2:
A support bracket acts as an intermediary between the encoder assembly and the rig structure. This bracket can be temporarily attached to existing rig components (such as the boom or support structure) without requiring permanent welding modifications, thereby obtaining approval more easily.
4Adaptability or versatility
If the support rod is used to support the linear bearing, then the system can handle lateral wire movement, but the rod deforms or fails under changing load conditions causing system downtime
Solution Approach 1:
The invention extracts the measurement function from the wire support mechanism entirely. By measuring drum rotation directly with an encoder wheel, the system eliminates the need for linear bearings and support rods that must handle lateral wire movement, thereby eliminating their deformation and failure modes.
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
This solution provides accurate depth measurement by eliminating variables related to wire deflection and tension, reduces the need for rig modifications, and enhances system reliability and accuracy across varying pile lengths, while withstanding harsh installation conditions.
Implementation Method 1
an encoder assembly having a support bracket fixably attachable to a first associated structural component of an associated pile installation machine... a load arm rotatable about the load arm axis and has a base end near the load arm axis and a distal end spaced from the load arm axis. The load arm can further include a wheel near the distal end that is rotatable about a wheel axis and the at least one encoder assembly further including an encoder joined to the wheel such that the wheel drives the encoder as it rotates.
Implementation Method 2
a wheel force biasing assembly loaded between the support bracket and the load arm configured to urge the load arm and wheel about the load arm axis into an engaged condition relative to the associate pile installation machine such that the wheel frictionally engages a surface of a second associated structural component
Data Source
AI summary
A measurement device system and method of using the same for determining the depth of a pile being installed and/or the equipment used to install the pile. The device including an encoder assembly having a support attachable to a structural component of a rig wherein the support has a pivot joint coaxial with a load arm axis. The encoder assembly has a load arm rotatable about the arm axis and with a wheel near its distal end that is rotatable about a wheel axis with an encoder joined to the wheel that moves with the wheel. The encoder assembly further including a biasing assembly to urge the load arm and wheel into an engaged condition relative to the associated pile installation machine such that the wheel frictionally engages a surface of another structural component of the rig. Thus, the displacement of the first structural component relative to the second component rotates the wheel about the wheel axis and the encoder. This information can then be used to determine pile depth.