Belt Sander Arm Retaining Unit Prevents Vibration Loosening
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Solution Overview
Problem
Conventional hand-held belt sanders experience safety concerns due to loose screw bolts caused by vibration, leading to potential separation of the sanding belt segment from the body segment during operation.
Innovation Solution
The hand-held belt sander incorporates a retaining unit with an annular groove and protrusions to secure the arm to the head, and a positioning unit with engaging grooves and an engaging member to maintain the arm's position, preventing separation and allowing for easy adjustment and secure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw bolt is used to secure the sanding belt segment to the body segment, then the sanding belt can be firmly positioned, but the screw bolt may loosen due to vibration during operation
Solution Approach 1:
The positioning device is segmented into multiple functional components: a positioning member with positioning protrusions that engage with positioning grooves, a retaining member with retaining protrusions that engage with retaining grooves, and a fastening member. This segmentation allows the positioning function and retaining function to be separated, with each component optimized for its specific function while working together to prevent loosening under vibration.
Solution Approach 2:
The positioning protrusions and retaining protrusions are pre-configured in specific positions and orientations before assembly. The positioning protrusions are preliminarily positioned to engage with positioning grooves at predetermined angles, and the retaining protrusions are preliminarily positioned to engage with retaining grooves, ensuring that when the fastening member is tightened, the components are already in their correct positions and will not loosen during operation.
2Stability of the object's composition
If the sanding belt segment is tightly secured to prevent separation, then operational stability is improved, but adjustment and repositioning become difficult
Solution Approach 1:
The positioning device employs a dynamic fastening mechanism where the fastening member can be easily tightened to secure the sanding belt segment in position during operation, and just as easily loosened when adjustment is needed. The positioning protrusions and retaining protrusions are designed to engage with their respective grooves firmly when tightened, providing stability, but can be quickly disengaged when the fastening member is loosened, enabling easy repositioning.
3Adaptability or versatility
If the arm is made rotatable about the axis for flexible positioning, then adaptability to different working spaces is improved, but the risk of accidental rotation or separation increases
Solution Approach 1:
The arm assembly is segmented into a rotatable arm portion and a fixed body portion, with the rotatable arm containing the positioning member and retaining member. This segmentation allows the arm to rotate freely about the axis for positioning flexibility, while the positioning and retaining mechanisms are integrated into the arm itself, ensuring that when the fastening member is tightened, the arm is securely locked at the desired position without risk of accidental rotation or separation.
4Device complexity
If a simple screw bolt positioning device is used, then device complexity is reduced, but safety concerns arise from loosening and separation
Solution Approach 1:
The positioning device merges multiple functions into a single integrated assembly: the positioning member with positioning protrusions for angular positioning, the retaining member with retaining protrusions for preventing separation, and the fastening member for securing both functions. This merging provides enhanced safety and reliability compared to a simple screw bolt, while maintaining relatively simple device complexity through the use of straightforward mechanical components that work together in a coordinated manner.
Data Source
AI summary
A hand-held belt sander includes a head, an arm, a retaining unit, and a positioning unit. The head includes a mounting seat surrounding an axis. The arm has a sleeve segment mounted to the mounting seat. The retaining unit has an annular groove formed in the mounting seat, and multiple protrusions disposed on the sleeve segment and engaging the annular groove. The positioning unit includes multiple engaging grooves formed in the mounting seat, and an engaging member disposed on the sleeve segment. When the engaging member engages one of the engaging grooves, the arm is positioned relative to the head at an operating position. When the engaging member is disengaged from the one of the engaging grooves, the arm is rotatable about the axis relative to the head.