Wire Ratchet Member for Recoil Starter Torque Transmission
Solution Overview
Problem
The existing ratchet mechanisms in recoil starters require complex processing steps, including bending and forming inclined surfaces, which increase manufacturing costs without significantly improving performance.
Innovation Solution
A recoil starter design featuring a wire-like ratchet member with a circular section, a rotary shaft portion, an arm portion bent at a right angle, and a distal end portion that protrudes to engage with a drive pulley, eliminating the need for inclined surfaces and reducing manufacturing costs through a simpler bending process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ratchet member with an inclined surface is used, then the ratchet member can engage with the drive pulley to transmit torque, but the manufacturing cost increases due to additional processing steps for bending and forming the inclined surface
Solution Approach 1:
The ratchet member is designed with a curved engagement surface that engages with the drive pulley through rotational movement. The wire-like ratchet member rotates to allow its engagement surface to contact the drive pulley's inner peripheral surface, eliminating the need for inclined surface processing while maintaining torque transmission capability.
Solution Approach 2:
The ratchet member transitions from a rigid inclined surface design to a rotatable wire-like structure. By changing the geometric parameters and allowing rotational movement, the design achieves torque transmission without requiring complex inclined surface formation, thereby reducing manufacturing steps and cost.
2Reliability
If the ratchet member is designed with complex bending and inclined surface formation, then the engagement with the drive pulley is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The wire-like ratchet member utilizes its circular cross-section and rotational capability to engage with the drive pulley. The curved geometry of the rotating wire provides reliable engagement through continuous contact with the drive pulley's inner peripheral surface, simplifying the manufacturing process while maintaining engagement reliability.
Solution Approach 2:
Instead of forming an inclined surface on the ratchet member to achieve engagement, the invention inverts the approach by using a rotatable wire-like structure that engages through rotation. This reversal of the conventional design approach simplifies manufacturing while achieving the same engagement function.
3Ease of manufacture
If a wire-like ratchet member with circular section is used, then the manufacturing cost is reduced and processing is simplified, but the ability to transmit torque effectively may be compromised
Solution Approach 1:
The wire-like ratchet member is designed to rotate dynamically during engagement with the drive pulley. This rotational movement allows the circular cross-section to maintain continuous contact with the drive pulley's inner peripheral surface, ensuring effective torque transmission despite the simple wire-like structure.
Solution Approach 2:
The circular cross-section of the wire-like ratchet member, when rotated, creates a curved engagement path with the drive pulley. This curvature enables the simple wire structure to effectively transmit torque through continuous rotational contact, maintaining transmission efficiency while simplifying manufacturing.
4Reliability
If the distal end portion of the ratchet member protrudes to engage with the drive pulley, then torque transmission is achieved, but the risk of locking in the opening edge increases
Solution Approach 1:
The ratchet member is designed to rotate dynamically during engagement, allowing the distal end portion to maintain contact with the drive pulley's inner peripheral surface through rotational movement. This dynamic rotation prevents the distal end from locking in the opening edge while ensuring continuous torque transmission.
Solution Approach 2:
The wire-like ratchet member's circular cross-section, when rotated, creates a curved engagement path that naturally prevents locking. The rotational movement allows the distal end to glide along the drive pulley's surface rather than catching on the opening edge, eliminating the locking risk while maintaining torque transmission.
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 design reduces manufacturing costs, minimizes sliding resistance, prevents locking issues, and ensures efficient torque transmission while maintaining performance by using a wire-like ratchet member with a circular section that can be easily manufactured and supports loads effectively.
Implementation Method 1
the rotated distal end portion engages with the drive pulley so as to transmit torque of the rope reel to the drive pulley
Implementation Method 2
a control member which is attached coaxially with the rope reel so that the control member can rotate with friction resistance given thereto
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
[Problem] To provide a recoil starter which is provided with a ratchet member smoothly sliding on an inner peripheral surface of a drive pulley and capable of being manufactured at a low cost. [Solution] A recoil starter is provided with a circular cross section ratchet member (16) rotatably mounted on a shaft hole (14b) . The ratchet member (16) is configured by: a rotary shaft portion (16a) inserted into the shaft hole (14b); an arm portion (16b) bent at a substantially right angle and extending from the rotary shaft portion (16a) ; and a distal end portion (16c) bent parallel to the rotary shaft portion (16a) and extending from the arm portion (16b). The ratchet member (16) rotates upon rotation of a rope reel (14) in an engine start direction, engages with a drive pulley (15) by the rotation, and transmits torque of the rope reel (14) to the drive pulley (15).