Tapered Spindle Socket Interface Reduces Lost Motion
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Solution Overview
Problem
The interface between the spindle and socket in discontinuous drive power tools experiences inefficiencies due to tolerance and wear, leading to increased lost motion and reduced energy transfer efficiency.
Innovation Solution
The implementation of tapered surfaces on both the spindle and socket, which concentrically locate each other, reduces lost motion and wear, enhancing torque transmission and alignment, and includes a locking mechanism using a biased pin and spring to secure the socket to the spindle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a male-to-female square socket interface is used to connect the spindle and socket, then the connection is simple and easy to manufacture, but tolerance and wear increase lost motion and reduce energy transfer efficiency
Solution Approach 1:
The patent changes the geometric parameters of the interface from a square cross-section to a tapered cross-section. This parameter change allows the interface to maintain ease of manufacture while significantly reducing lost motion and improving energy transfer efficiency through the tapered geometry that eliminates radial clearance.
Solution Approach 2:
The patent applies a tapered (curved) geometry to the spindle and socket interface instead of a straight square cross-section. This curvature in the form of a taper angle creates a wedge effect that eliminates clearance and improves energy transfer while maintaining manufacturability through standard tapering processes.
2Device complexity
If a male-to-female square socket interface is used, then the connection structure is simple, but wear increases lost motion between the spindle and socket
Solution Approach 1:
The tapered geometry introduces a curved surface configuration that provides self-aligning properties. The taper angle creates a natural guidance mechanism that maintains precise alignment between spindle and socket during operation, reducing wear and lost motion while adding minimal complexity to the connection structure.
3Reliability
If tapered surfaces are implemented on the spindle and socket, then alignment and torque transmission are improved, but the device complexity increases
Solution Approach 1:
The patent modifies the interface geometry by applying a taper angle to the spindle and socket surfaces. This parameter change improves torque transmission reliability by eliminating radial clearance and enhancing alignment, while the complexity increase is minimal as tapering is a standard manufacturing process that can be applied to existing square interface designs.
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 configuration improves the accuracy and efficiency of energy transfer by minimizing lost motion and wear, ensuring precise alignment and maintaining torque transmission effectively.
Implementation Method 1
a locking mechanism using a biased pin and spring to secure the socket to the spindle
Implementation Method 2
a locking mechanism using a biased pin and spring to secure the socket to the spindle
Implementation Method 3
The implementation of tapered surfaces on both the spindle and socket, which concentrically locate each other, reduces lost motion and wear
Data Source
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AI summary
A discontinuous drive power tool assembly for generating rotational torque. The tool assembly includes a spindle having a first end portion configured to receive a socket. The first end portion has a primary engaging surface and a tapered surface spaced from a distal end of the first end portion. The primary engaging surface and the tapered surface are configured to engage corresponding surfaces on the socket. The tool assembly also includes a pulse hammer engagable with a second end portion of the spindle that is opposite the first end portion, and a motor including a motor shaft engagable with the pulse hammer, the motor being configured to rotate the pulse hammer.