Extendible Working Machine Rod Section with Helical Drive Shaft
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Solution Overview
Problem
Extendible working machines used at high elevations face challenges in achieving a balance between longer extension, lighter weight, and safety, often resulting in a thick and heavy rod section that complicates weight reduction and workability.
Innovation Solution
The design incorporates a rotation/drive section, a working section, and an extendible rod section with a drive shaft featuring helical grooves, allowing for a smaller diameter and reduced weight, along with a tube body structure that includes an outer and inner tube with bearings and springs to facilitate extension and retraction, enabling efficient transmission of rotational force while minimizing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rod section is made thick and heavy to ensure safety during extension, then reliability is improved, but weight increases and workability deteriorates
Solution Approach 1:
The patent applies nesting by placing the inner tube inside the outer tube, and the drive shaft inside the tube body. This nested structure allows multiple components to occupy the same spatial envelope, enabling the rod section to achieve extended length without proportionally increasing outer dimensions and weight. The inner tube can slide within the outer tube to provide extension while maintaining a compact overall structure.
Solution Approach 2:
The rod section is segmented into multiple components: outer tube, inner tube, drive shaft, and tube body. This segmentation allows each component to be optimized independently for its specific function while contributing to the overall lightweight design. The segmented structure enables extension through relative movement of segments rather than requiring a single heavy extended structure.
2Length of moving object
If the rod section is extended longer to reach high elevations, then working height is improved, but weight increases and handling becomes more difficult
Solution Approach 1:
The nested configuration of inner tube within outer tube allows the rod section to achieve extended length while maintaining a compact retracted profile. When retracted, the inner tube fits inside the outer tube, minimizing the overall length and weight that must be handled. When extended, the inner tube slides outward to provide the necessary working length without requiring a completely separate extension mechanism.
Solution Approach 2:
The rod section employs dynamic extension capability where the inner tube can slide relative to the outer tube during operation. This dynamic structure allows the length to be adjusted based on working requirements rather than being fixed at maximum length, enabling the user to carry a lighter, more manageable configuration when full extension is not needed.
3Ease of manufacture
If conventional drive shaft structures are used, then manufacturing is simpler, but diameter and weight are larger
Solution Approach 1:
The drive shaft features helical grooves formed by twisting, giving it a curved/helical geometry rather than a straight cylindrical form. This helical structure allows the drive shaft to transmit rotational force more efficiently while potentially reducing the required diameter compared to conventional straight shafts with equivalent torque capacity. The curved geometry optimizes the mechanical advantage for power transmission.
Solution Approach 2:
The drive shaft utilizes helical grooves with specific geometric parameters (pitch, depth, angle) that are optimized to transmit rotational force efficiently. By changing the geometric parameters from a conventional straight shaft to a helical configuration, the shaft can achieve the same or better torque transmission with reduced diameter and weight, while still being manufacturable using standard machining processes.
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 configuration results in a lighter, easier-to-handle extendible working machine with enhanced workability and reduced fatigue, capable of stable operation at high elevations, even for users with smaller hands or weaker individuals.
Implementation Method 1
the outer tube containing springs disposed between the bearings, the inner tube moving in the outer tube so as to extend or compress the springs
Implementation Method 2
the drive shaft having a plurality of helical grooves on the surface of the drive shaft, the pipe shaft having a connecting pipe on the proximal end of the pipe shaft with the drive shaft inserted into the connecting pipe, the connecting pipe having a plurality of helical convex portions on the inner surface of the connecting pipe
Implementation Method 3
the bearing including a bush holder that is movable relative to the outer tube in the axial direction and is incapable of rotating in the outer tube, a drive bush that has helical convex portions on the inner surface of the drive bush, the convex portions being movable in the grooves on the surface of the drive shaft, and a bearing disposed between the inner surface of the bush holder and the outer surface of the drive bush
Data Source
AI summary
An extendible working machine has a rotation/drive section, a working section, and a rod section which connects the rotation/drive section and the working section, transmits rotational force to the working section, and can be extended and retracted. The rod section has a tube body which can be extended and retracted, and also has a shaft body which extends in the axial direction within the tube body and which can be extended and retracted together with the tube body. The shaft body has a pipe shaft which is supported within the inner tube in a rotatable manner. Helical grooves are formed in the surface of the drive shaft. The drive shaft is connected to the pipe shaft so the pipe shaft can move in the axial direction along the outer surface of the drive shaft and so the rotation of the drive shaft is transmitted to the pipe shaft.