Flex Shaft Crimped Lock Sleeve for Rotary Knife
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Solution Overview
Problem
Prior flexible shaft drive transmissions experience significant lubricant leakage at the handle assembly coupling end due to gravity, leading to increased friction, heat, and reduced operating life, and the drive transmitting shaft is not securely positioned within the casing, causing inconvenience and contamination.
Innovation Solution
The flexible shaft drive transmission includes a tapered motor end coupling and a coupler fitting with an enlarged head to prevent lubricant leakage and secure the drive transmitting shaft within the outer casing, featuring a bushing with a longitudinal central opening and a coupler fitting that provides a seal and constrains axial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional flexible shaft drive transmission is used without additional sealing components, then the structure remains simple, but lubricant leakage occurs at the handle assembly coupling end due to gravity
Solution Approach 1:
A seal ring is introduced as an intermediary component between the drive transmitting shaft and the outer casing to prevent lubricant leakage. The seal ring acts as a mediator that blocks the leakage path without complicating the overall structure, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The outer casing is divided into separate sections with the handle assembly coupling end equipped with specific sealing features. This segmentation allows targeted lubrication retention at the problematic area without requiring complete structural redesign, balancing reliability improvement with minimal complexity increase.
2Ease of operation
If the drive transmitting shaft is left unsecured within the casing, then the assembly process is simplified, but the shaft becomes insecurely positioned causing inconvenience and contamination
Solution Approach 1:
The outer casing is pre-formed with a recessed portion that automatically positions and secures the drive transmitting shaft during assembly. This preliminary structural preparation ensures secure shaft positioning without requiring additional complex assembly steps or components, resolving the contradiction between operational security and assembly simplicity.
3Duration of action of moving object
If lubricant is allowed to leak at the handle assembly coupling end, then the structure remains simple without additional sealing, but friction and heat increase reducing operating life
Solution Approach 1:
A simple, inexpensive seal ring is used to prevent lubricant leakage and protect the drive transmitting shaft. This low-cost component extends the operating life by maintaining proper lubrication without introducing complex sealing systems, effectively resolving the contradiction between durability and structural simplicity.
Data Source
AI summary
A method of assembling a flexible shaft drive transmission (4701) coupled between a drive motor and a power operated tool including the steps of: providing a drive transmitting shaft assembly (4800) including a flexible, elongated flex shaft (4702); providing an outer casing assembly (4702) including an outer casing (4704) defining a longitudinally extending throughbore and having a motor end (4710) and a tool end (4780); sliding a lock sleeve (4750) onto the motor end of the outer casing to a recessed position with respect to the motor end of the casing; inserting the motor end of the flex shaft through the tool end of the outer casing; affixing a driven fitting (4814) to the motor end of the flex shaft; advancing the lock sleeve to overlie the motor end of casing; and affixing a casing portion (4762) of the lock sleeve to the outer casing.