Driving Tool Wire Twist Prevention Mechanism
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Solution Overview
Problem
Existing driving tools experience twisting of string-like members, such as wires, due to mismatched speeds of extension and contraction of coil springs, leading to potential wire breakage and deviation of the plunger position.
Innovation Solution
Incorporation of a rotation prevention portion, including a guide portion, slider portion, and low friction member to prevent the moving member from rotating relative to the urging member, thereby maintaining alignment and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire connects the moving member and plunger to transmit driving force, then the driving force transmission is achieved, but the wire twists and may break due to speed mismatch between coil spring and moving member
Solution Approach 1:
A rotation prevention portion is introduced as an intermediary component between the moving member and the wire. This rotation prevention portion includes a guide portion formed on the cylinder and a slider portion on the moving member that moves along the guide portion, preventing the moving member from rotating relative to the coil spring and thus preventing wire twisting
Solution Approach 2:
The rotation prevention portion is configured to prevent rotation of the moving member before the wire can twist. By constraining the moving member's rotational movement in advance through the guide portion and slider portion mechanism, the system prevents the harmful twisting effect from occurring
2Productivity
If the moving member is allowed to move freely with the coil spring, then the driving force transmission is efficient, but the moving member rotates relative to the coil spring causing wire twisting
Solution Approach 1:
The rotation prevention portion applies a localized constraint only in the rotational direction while allowing free movement in the launch direction. The guide portion and slider portion configuration restricts rotation around the central axis but does not impede the linear motion needed for driving force transmission
Solution Approach 2:
The movement constraints are segmented into specific degrees of freedom: the guide portion and slider portion separate the rotational constraint from the linear motion, allowing the system to maintain productivity while improving stability
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
Prevents twisting of the string-like member, ensuring consistent operation and reducing wear, thus enhancing the reliability and longevity of the driving tool.
Implementation Method 1
a low friction member disposed between the moving member and the urging member, and a friction coefficient of the low friction member relative to the urging member may be smaller than that of at least the moving member
Implementation Method 2
an urging member that is extendable and contractible and is configured to serve as a drive source of the plunger
Implementation Method 3
a coil spring or the like capable of urging the plunger
Data Source
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AI summary
A driving tool includes: a plunger movable in a launch direction of a fastener; an urging member that is extendable and contractible and is configured to serve as a drive source of the plunger; a moving member that is disposed at an end portion in an extension-contraction direction of the urging member and is movable in the extension-contraction direction of the urging member; a string-like member configured to connect the moving member and the plunger and transmit a driving force of the urging member to the plunger via the moving member; and a rotation prevention portion configured to prevent rotation of the moving member around a central axis in the extension-contraction direction of the urging member.