Hammer Drill Tool Holder Ball Retraction With Inclined Guide Washer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing striking tools, such as electric hammers and hammer drills, face issues with the smooth retraction of balls into the tool holder when inserting a tip tool, leading to potential obstruction and difficulty in attaching the tool due to uneven force distribution.
Innovation Solution
The striking tool design incorporates a guide washer with a conical receiver and a projection that allows the balls to move backward, enabling the tool holder to receive the tip tool smoothly by maintaining an inclined posture, facilitating the retraction of both balls and ensuring secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the retracted portion protrudes more rearward to allow the ball to move greatly, then the ball can retract more, but the tip tool pressed further may apply a greater force in the radial direction of the guide washer than the force in the pressing direction, preventing the tip tool from being pressed further
Solution Approach 1:
The guide washer is designed with different surface qualities in different regions: a smooth pressing surface on the front side for axial pressing, and a retracted portion with inclined surfaces on the rear side for ball retraction. This local differentiation allows the pressing surface to resist radial forces while the retracted portion facilitates ball movement.
Solution Approach 2:
The retracted portion is designed with asymmetric inclined surfaces that are angled relative to the axial direction. This asymmetric geometry allows the ball to be guided rearward and radially outward during retraction, converting axial pressing motion into radial ball displacement without generating excessive radial forces on the guide washer body.
2Reliability
If the two balls are made to retract reliably, then the tip tool can be smoothly received, but the structure becomes more complex with the projection and inclined posture mechanism
Solution Approach 1:
The guide washer combines multiple functions into a single component: it provides the pressing surface for axial force transmission, forms the retracted portion for ball retraction guidance, and creates the inclined posture through its asymmetric geometry. This merging eliminates the need for separate retraction mechanisms while ensuring reliable ball retraction.
Solution Approach 2:
The guide washer's own geometry, particularly the retracted portion with inclined surfaces, automatically guides the ball retraction process. When the tip tool is pressed axially, the ball naturally follows the inclined surfaces of the retracted portion, causing self-guided rearward and radial movement without requiring additional actuating mechanisms.
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 design ensures reliable retraction of the balls, allowing for easy and secure insertion of the tip tool, enhancing the tool's usability and preventing the tool from slipping off during operation.
Implementation Method 1
an urging member between the tool holder and the abutting member, the urging member urging the two balls forward in the reception holes with the abutting member
Implementation Method 2
a projection between the abutting member and the pressure ring, the projection being configured to cause, with the pressure ring at the locked position, the abutting member to be in an inclined posture with respect to the axis of the tool holder to allow a first ball of the two balls to move more backward than a second ball of the two balls
Data Source
AI summary
Two balls can reliably retract for smooth insertion of a tip tool into a tool holder. A hammer drill includes a tool holder, two balls in reception holes in the tool holder, a guide washer urging the balls forward in the reception holes with a coil spring, a pressure ring adjacent to a front of the guide washer, and an operation sleeve allowing the pressure ring to move backward and forward between locked and unlocked positions of the two balls. The guide washer includes, on its front surface, a projection toward the pressure ring to cause, with the pressure ring at the locked position, the guide washer to be inclined with respect to an axis of the tool holder for a first ball to move more backward than a second ball.