Hammer Drill Housing Tapered Interface Vibration Damping
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Solution Overview
Problem
Existing hammer drills suffer from vibration transmission issues, making it difficult for users to accurately direct the tool bit due to inadequate guidance and damping mechanisms.
Innovation Solution
A power tool design featuring a housing with engaging portions that taper towards the working member, allowing the transmission mechanism to align with the tool bit and increase damping effect as pressure is applied, utilizing biasing means like coil springs to reduce vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the transmission mechanism is allowed to move freely relative to the housing to dampen vibrations, then vibration transmission to the user is reduced, but the user loses accurate control over the tool bit alignment
Solution Approach 1:
The tapered engaging portions act as an intermediary mechanism between the transmission mechanism and housing. They provide guided movement that allows vibration damping while maintaining alignment control, mediating between the conflicting requirements of freedom of movement and precise positioning.
Solution Approach 2:
The engaging portions allow the transmission mechanism to dynamically adjust its position relative to the housing during operation. The tapered surface enables controlled movement that adapts to vibration conditions while maintaining proper alignment, transitioning from a static to a dynamic connection.
2Ease of operation
If the transmission mechanism is constrained to maintain alignment with the housing, then the user can accurately direct the tool bit, but vibration transmission to the user increases
Solution Approach 1:
The tapered engaging portions serve as a mediator that allows controlled relative movement between the transmission mechanism and housing. This intermediary structure enables the system to maintain alignment while accommodating vibration-induced movements that would otherwise be transmitted directly to the user.
Solution Approach 2:
The tapered surface geometry changes the interaction parameters between the engaging portions. As the transmission mechanism moves relative to the housing, the contact point moves along the tapered surface, changing the effective engagement parameters to allow vibration damping while maintaining alignment.
3Stability of the object's composition
If rigid connection between transmission mechanism and housing is used, then alignment is maintained, but vibration damping effect is lost
Solution Approach 1:
The tapered engaging portions transform the rigid static connection into a dynamic semi-rigid connection. This allows the system to maintain stability when needed while permitting controlled movements for vibration damping, adapting its rigidity based on operational conditions.
Solution Approach 2:
The connection between the transmission mechanism and housing is segmented into discrete engaging portions with tapered surfaces. This segmentation allows independent movement of the transmission mechanism relative to the housing while maintaining overall alignment, breaking the rigid monolithic connection into flexible modular elements.
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
Enhances user control over the tool bit alignment and reduces vibration transmission to the user, improving operational accuracy and comfort by guiding the transmission mechanism and increasing damping effect.
Implementation Method 1
damping means for damping transmission of vibrations from the working member to the housing
Implementation Method 2
biasing means disposed between said transmission mechanism and the housing for permitting displacement of the transmission mechanism out of engagement with the housing
Data Source
AI summary
A hammer drill has a transmission housing 280 is formed from two clamshell halves of durable plastics or cast metal material. The transmission housing 280 is mounted on first and second damping springs 284 and 286 at its rearward end. The transmission housing 280 is also mounted on parallel rails (not shown) disposed within the tool housing 222 such that the transmission housing 280 can slide a small distance relative to the tool housing 222. The forward end of the transmission housing 280 has a generally part conical portion 290, which abuts a corresponding part conical portion 292 formed on the tool housing 222. The interface defined by conical portions 290 and 292 defines a stop against which the transmission housing 280 rests against the tool housing 222 in the inoperative condition of the hammer drill 220. When the hammer drill 220 is being used, a gap opens up between the conical surfaces 290 and 292 which helps to damp axial and lateral vibrations that would otherwise be transmitted from the tool bit (not shown) to the user. However, the gap is sufficiently small that the hammer drill 220 and the transmission housing 280 can still be adequately controlled by the user, and the part conical shape of the interface also assists in aligning the transmission housing 280 with the tool housing 222 in order to give a user greater control over the direction of the tool bit.