Biasing Device Eliminates Slop in Strength Training Press Arm Locking
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Solution Overview
Problem
Existing strength training apparatuses experience 'slop' due to gravity, leading to a clunking noise and uneven resistance during initial movement, as the locking device's selector pin engages with the wrong side of the selector holes, disrupting smooth interaction between the operator and the resistance device.
Innovation Solution
A biasing device, such as a gas spring, is integrated to bias the press arm with respect to the resistance arm, ensuring the selector pin engages correctly with the selector holes, eliminating slop and providing consistent resistance from the outset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device with selector pin and selector holes is used to retain the press arm in fixed angular positions, then the press arm can be held securely at predetermined positions, but gravity causes the selector pin to engage with the wrong side of the selector holes creating slop and clunking noise during initial movement
Solution Approach 1:
A biasing device (spring or gas spring) is introduced to counteract the effect of gravity on the selector pin. The biasing device applies a force that keeps the selector pin engaged with the correct side of the selector holes, preventing the slop and clunking noise that would otherwise occur when gravity causes misengagement during initial movement.
Solution Approach 2:
The biasing device pre-applies a force to the selector pin to prevent the harmful effect of gravity-induced misengagement before it occurs. By maintaining constant biasing pressure, the system proactively prevents the selector pin from dropping into the wrong side of the selector holes, eliminating the clunking noise and slop before they can occur during operation.
2Ease of operation
If the selector pin engages with the wrong side of selector holes due to gravity, then the locking device fails to provide consistent resistance, but adding a biasing device to prevent this engagement increases the device complexity
Solution Approach 1:
The biasing device serves as a counterbalancing mechanism that offsets gravitational effects on the selector pin. This simple mechanical addition provides consistent resistance by ensuring proper engagement without requiring complex control systems or multiple locking mechanisms.
Solution Approach 2:
The biasing device acts as an intermediary element between the selector pin and the selector holes. It mediates the interaction by maintaining proper engagement forces, ensuring that the selector pin consistently engages with the correct side of the selector holes and providing smooth, consistent resistance during operation.
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
The biasing device ensures a smooth and consistent resistance experience by maintaining the selector pin's engagement with the correct side of the selector holes, eliminating the clunking noise and providing a seamless interaction between the operator and the resistance device.
Implementation Method 1
A biasing device, such as a gas spring, is integrated to bias the press arm with respect to the resistance arm
Data Source
AI summary
A strength training apparatus comprises a frame and press arm that is connected to a resistance arm at a pivot point so that the press arm is pivotable with respect to the resistance arm and so that the press arm and resistance arm are pivotable together with respect to the frame. A locking device is configured to retain the press arm in first and second fixed angular pivot positions with respect to the resistance arm. A resistance device is configured to resist pivoting movement of the press arm together with the resistance arm with respect to the frame. A biasing device is configured to bias the press arm with respect to the resistance arm so as to remove any slop in the locking device that otherwise would be caused by gravity, and so that an initial movement of the press arm is resisted by the resistance device.