Limited Rotation Slewing Ring Crane Sensor
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Solution Overview
Problem
Limited rotation slewing ring cranes lack a cost-effective and structurally simple solution for measuring the rotation of the column with respect to the pedestal, as existing solutions for unlimited rotation cranes are complex and expensive.
Innovation Solution
A rotative sensor system comprising a tubular body integral with the column, a stationary body, and a wheel with a deformable auxiliary crown, where the wheel's rotation is sensed to measure the column's rotation angle, offset from the column's rotation axis, allowing for mechanical stop elements to limit rotation and provide angular position feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotative encoder sensor is used to measure column rotation in unlimited rotation slewing ring cranes, then the rotation measurement function is achieved, but the structural complexity and cost increase significantly
Solution Approach 1:
The patent extracts the rotation measurement function from the complex electric joint system and implements it through a simpler alternative: a wheel rotatable with respect to the stationary body, where the wheel's rotation is sensed to determine the column's rotation angle. This separates the measurement function from the hydraulic/electric connection system, achieving the same measurement purpose with reduced structural complexity
Solution Approach 2:
The patent uses a wheel that rotates in correspondence with the column's rotation, creating a mechanical copy of the rotational motion. The sensing means detects the wheel's angular position rather than directly measuring the column's rotation, providing an indirect but accurate measurement method that simplifies the overall system structure
2Adaptability or versatility
If electric and hydraulic joints are installed at the rotative coupling to enable unlimited rotation, then the column can rotate without limit, but the structural complexity increases due to the need to prevent twisting of hydraulic pipes and electric cables
Solution Approach 1:
The patent removes the electric and hydraulic joints from the rotative coupling system by accepting limited rotation. This extraction eliminates the complex components needed to prevent twisting of pipes and cables, significantly simplifying the structure while maintaining adequate operational capability through mechanical stop elements
Solution Approach 2:
Instead of enabling unlimited rotation through complex joints and accepting the resulting complexity, the patent inverts the approach by deliberately limiting rotation to simplify the system. The mechanical stop elements define the rotation arc, turning the limitation into a design feature rather than a constraint
3Measurement precision
If unlimited rotation slewing ring cranes use rotative encoders associated with electric joints, then accurate rotation measurement is achieved, but the cost increases due to the complexity of the electric and hydraulic joints
Solution Approach 1:
The patent replaces the expensive rotative encoder associated with complex electric joints with a simpler wheel and sensing means combination. The wheel is a basic mechanical component that can be manufactured at lower cost, and the sensing means detects its position without requiring the expensive electric joint infrastructure
Solution Approach 2:
The patent creates a mechanical copy of the column's rotation through the wheel, which rotates in correspondence with the column's angular position. This copying mechanism allows for accurate measurement without the need for expensive direct measurement devices like rotative encoders integrated into electric joints
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 a structurally simplified and cost-effective means to measure the rotation angle of the column, enabling effective operation while avoiding the complexity and expense of unlimited rotation crane sensors.
Implementation Method 1
a wheel, rotatable with respect to the stationary body about a second rotation axis, which is meshed by the tubular body, wherein the second rotation axis of the wheel with respect to the stationary body is offset with respect to the first rotation axis
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A limited rotation slewing ring crane (1) comprises: a pedestal (3), a column (2) rotatively coupled, about a first rotation axis, to the pedestal (3) by a slewing ring rotative coupling (6), and means for limiting the relative rotation of the column (2) with respect to the pedestal (3). The crane (1) further comprises a rotative sensor (10) adapted to measure a rotation angle of the column (2) with respect to the pedestal (3), wherein said rotation sensor (10) comprises: - a tubular body (11) axially extending from the base of the column (2) and rotatively integral with the same; - a stationary body (13) connected to the pedestal (3) and a wheel (14), rotatable with respect to the stationary body (13) about a second rotation axis, which is meshed by the tubular body (11), wherein the second rotation axis of the wheel (14) with respect to the stationary body (13) is offset with respect to the first rotation axis of the column (2) with respect to the pedestal (3); - means for sensing the angular position of the wheel (14) with respect to the stationary body (13).