Offset Saw Blade Holder Shim Reinforcement
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Solution Overview
Problem
Reciprocating saws with slotted drive shafts are prone to stress risers and potential failure under impact loading, leading to deflection or breaking of the drive shaft halves during foam trimming operations.
Innovation Solution
An offset saw blade mounting assembly with a cylindrical, slotted drive shaft is reinforced using a shim member that fills the drive shaft slot, paired with a guide channel assembly and retaining screws to secure the mounting block, preventing deflection and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a slotted drive shaft is used to allow mounting block attachment, then the saw blade can be mounted to the drive shaft, but the slot creates stress risers that lead to drive shaft deflection or breaking under impact loading
Solution Approach 1:
A reinforcement member is introduced as an intermediary element between the mounting block and the drive shaft. This reinforcement member fits into the slot and provides additional support, distributing the mounting stresses away from the stress riser locations in the slot and preventing drive shaft deflection or breaking under impact loading.
2Adaptability or versatility
If the drive shaft slot is kept for mounting block attachment, then the saw can operate with the offset mounting assembly, but impact forces cause stress concentration and potential drive shaft failure
Solution Approach 1:
The reinforcement member is installed in advance in the drive shaft slot to cushion and absorb the impact forces before they can cause stress concentration and damage. This preemptive reinforcement ensures the drive shaft can withstand impact loading during foam trimming operations while maintaining compatibility with the offset mounting assembly.
Data Source
AI summary
An improved offset saw blade mounting assembly for use on a reciprocating power saw tool includes a shim member that is used to fill a central slot of the tool drive shaft. The shim member fills the slot and serves to reinforce the drive shaft and thereby reduce the likelihood of the drive shaft failing. The shim member may be a separate piece, or formed as part of a separate tubular insert, or integrally formed with the mounting block of the offset mounting assembly. A finger guard is also provided that substantially closes off any opening which may occur between the mounting assembly and the power tool.