Backpack Blower Flexible Shaft Drive for Wider Operating Range
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Solution Overview
Problem
Conventional blowers either carry heavy engines on the back, limiting operational range due to weight distribution, or are hand-held with restricted power and range due to weight and power transmission inefficiencies, and attachment types face reduced ability and size limitations.
Innovation Solution
A blower design featuring an engine on the back, a hand-held blower portion with a flexible shaft connecting the engine to a fan, and a power transmitting direction varying device using bevel gears to optimize power transmission without bending the shaft, allowing for a larger engine and reduced weight on the blower portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine and blower portion are carried on the back as a unit, then a large engine can be used, but heavy weight is applied on the back and operational range is limited
Solution Approach 1:
The blower system is divided into separate components: the engine is carried on the back while the blower portion is held by hand, connected through a flexible shaft. This segmentation allows the heavy engine to be positioned for optimal power while the lighter blower portion maintains operational flexibility and range.
Solution Approach 2:
A flexible shaft with outer tube is used to connect the engine to the blower portion, replacing rigid connections. This flexible coupling enables the operator to move the blower portion freely within a reasonable range without being constrained by the position of the engine on the back.
2Device complexity
If the engine and blower portion are held by hand as a unit, then the structure is simple, but total weight becomes large and engine power is limited
Solution Approach 1:
The system is segmented into a handheld blower portion and a separate engine unit carried on the back. This allows the blower portion to remain relatively light and simple while the engine can be a larger, more powerful unit that would be too heavy for handheld operation.
Solution Approach 2:
The flexible shaft acts as an intermediary power transmission element between the engine and blower portion, enabling power transfer while allowing spatial separation and reducing the weight that must be held by hand.
3Adaptability or versatility
If a flexible tube is used to connect the air ejection pipe to the blower portion, then the connection is flexible, but power of ejection air is reduced and length is limited
Solution Approach 1:
A flexible shaft with outer tube is used to transmit rotational power from the engine to the fan, providing flexibility in positioning while maintaining efficient power transmission. This is more effective than using a flexible tube for air flow, as it transmits mechanical power rather than fluid flow.
Solution Approach 2:
The patent replaces the flexible tube air flow system with a mechanical power transmission system using a flexible shaft and fan, achieving better power transmission efficiency while maintaining operational flexibility.
4Length of moving object
If the blower portion is attached to the tip end of a bush cutter, then the length is extended, but weight concentrates at the tip end causing the tip to lower and ability is reduced
Solution Approach 1:
The blower system is separated from the bush cutter, with the engine carried on the back and the blower portion held independently by hand. This eliminates the problematic weight concentration at the tip end that occurs when the blower is attached to the bush cutter.
Solution Approach 2:
By carrying the engine on the back rather than attaching it to the tip end, the weight distribution is balanced. The engine weight is supported by the operator's back rather than concentrating at the blower tip, preventing the tip from lowering and maintaining operational ability.
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
Enables efficient power transmission and reduced weight distribution, allowing for a larger engine to be used while maintaining a compact and effective blower design, enhancing operational range and usability.
Implementation Method 1
a flexible shaft (12), one end of which is connected to an output shaft (14) of the engine (7) and the other end of which is connected to a rotary shaft (16) of the fan (19)
Data Source
AI summary
In a blower, an engine is carried on the back, and a blower portion having a fan is held through a holding member by hand. One end of a flexible shaft, is connected to an output shaft of the engine and the other end of which is connected to a rotary shaft of the fan. The flexible shaft has a flexible outer tube for connecting a casing of the engine with a housing of the fan, and a rotary shaft formed of a helical coil rounded helically around the axial line of the outer tube and extending axially in the outer tube, one end of the rotary shaft being connected to the output shaft of the engine and the other end of the rotary shaft of the flexible shaft being connected to the rotary shaft of the fan. The rotary shaft of the flexible shaft is connected to the rotary shaft of the fan through a power transmitting direction varying device.