Rope-Pull Starting Device Torsion Damper Spring Reducing Operator Effort
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing manual starting mechanisms for internal combustion engines, such as those in chainsaws, require significant operator effort due to high forces encountered during the starting process, particularly during the compression stroke, leading to user fatigue and difficulty in initiating engine rotation.
Innovation Solution
A rope-pull starting device incorporating a torsion damper spring that interconnects the rope pulley with a hub, allowing for efficient transfer of starting force to the engine crankshaft, with a one-way rotational mechanism and a recoil spring to assist in engine starting by storing and releasing energy, reducing the effort required from the operator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a manual rope starting mechanism is used, then the device complexity is reduced, but the operator effort and difficulty in initiating engine rotation increase due to high forces during compression stroke
Solution Approach 1:
The recoil spring performs preliminary action by pre-storing energy in a wound state before the starting operation. When the operator pulls the rope, the spring unwinds and releases stored energy to assist rotation, reducing the effort needed during the critical compression stroke phase.
Solution Approach 2:
The recoil spring acts as an intermediary between the operator's pulling force and the engine crankshaft. It transfers and amplifies the operator's input force through elastic energy storage and release, providing mechanical assistance during the starting process without requiring complex automated systems.
2Ease of operation
If a recoil spring is added to store and release energy, then the ease of operation improves by reducing operator effort, but the device complexity increases
Solution Approach 1:
The recoil spring changes the energy parameter of the system by storing elastic potential energy during rope winding and releasing it during engine starting. This parameter change provides mechanical assistance without requiring complex control systems or multiple components.
Solution Approach 2:
The recoil spring operates through periodic action - being wound up during rope retraction and unwinding during engine starting. This cyclic energy storage and release pattern provides continuous assistance throughout the starting process while maintaining simple mechanical operation.
3Reliability
If a one-way rotational mechanism is implemented, then the reliability of force transfer improves, but the device complexity increases
Solution Approach 1:
The one-way rotational mechanism extracts and isolates the specific function of unidirectional force transfer from the overall starting system. By separating this function into a dedicated component, the system achieves reliable one-way power transmission while keeping the rest of the mechanism simple and maintainable.
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 enhances the starting performance by reducing the operator's effort during peak resistance periods, providing a smoother and easier engine start by storing energy during the initial stages of the compression stroke and releasing it when needed, thus reducing the overall felt resistance.
Implementation Method 1
A rope-pull starting device incorporating a torsion damper spring that interconnects the rope pulley with a hub, allowing for efficient transfer of starting force to the engine crankshaft, with a one-way rotational mechanism and a recoil spring to assist in engine starting by storing and releasing energy
Data Source
AI summary
A rope-pull starting device for an internal combustion engine including a hub, rope pulley, rope and torsion damper spring. The hub configured to drivingly engage an engine when the hub is rotated in a first direction. The rope pulley interconnects with the hub by a torsion damper spring. The torsion damper spring coupled at a first end to the hub and at a second end to the rope pulley, wherein the torsion damper spring is coiled from the first end connected to the hub, toward the rope pulley, in a second direction opposite to the first direction, and whereby the rope pulley is rotated in the first direction when the rope is unwound therefrom and the torsion damper spring responsively urges the hub to rotate in the first direction.