Bidirectional Ball Locking Mechanism for Shaft Grip Without Damage
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Solution Overview
Problem
Existing hand-operated locking mechanisms for bars or poles are not versatile enough to securely lock in either direction and can cause damage due to excessive friction, leading to issues with installation and durability.
Innovation Solution
A compact locking mechanism featuring a hollow inner cylinder with two rows of apertures and biased ball bearings that can be installed in either direction, utilizing wavy springs and inclined surfaces to ensure a secure frictional fit without damaging the shaft, allowing for easy sliding and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-sided locking mechanism is used, then the structure is simple, but it cannot lock securely in either direction
Solution Approach 1:
The locking mechanism is divided into two identical side members (first side member and second side member) that can function interchangeably. Each side member has its own ball bearing, aperture, and inclined surface, allowing the mechanism to lock securely regardless of installation direction. This segmentation creates symmetry that enables bidirectional locking capability.
Solution Approach 2:
The inclined surfaces on the side members are positioned at specific angles (e.g., 45 degrees) relative to the longitudinal axis, creating an asymmetric geometry that converts axial compression forces into radial clamping forces on the ball bearings. This asymmetric angle design ensures that the balls are forced into the apertures to engage the shaft effectively.
2Force
If steel balls are used for locking, then the gripping force is strong, but they can cause damage to the shaft by creating dents
Solution Approach 1:
The ball bearings are made from softer materials (brass, copper, or toughened plastics) specifically at the contact point with the shaft, while the rest of the locking mechanism structure remains strong and rigid. This local quality change allows the balls to deform slightly under load, distributing the contact pressure over a larger area and preventing dents on the shaft surface while still providing sufficient gripping force.
Solution Approach 2:
The locking mechanism uses composite material selection where the side members are made of strong structural material (metal) for overall strength, while the ball bearings are made of softer material (brass, copper, or plastic) for shaft protection. This material combination achieves both strong gripping force and shaft surface protection.
3Ease of operation
If the locking mechanism uses a spring bias system, then the balls can be easily retracted for sliding, but the structure becomes more complex
Solution Approach 1:
The locking mechanism transitions between two dynamic states: locked and unlocked. In the locked state, spring bias keeps the balls pressed against the shaft. In the unlocked state, axial movement of the side members away from each other allows the balls to retract from the apertures. This dynamic state transition enables easy sliding and removal while maintaining a relatively simple structure.
Solution Approach 2:
The inclined surfaces act as intermediaries that convert the axial separation movement of the side members into radial retraction movement of the ball bearings. When the side members move apart axially, the balls ride down the inclined surfaces and retract from the apertures, allowing the cylinder to slide freely on the shaft without requiring complex release mechanisms.
4Reliability
If the balls are tightly biased against the shaft, then the locking is secure, but the inner cylinder cannot slide freely on the shaft
Solution Approach 1:
The mechanism dynamically adjusts the ball bearing position based on the operational state. During normal operation, spring bias maintains tight contact between the balls and shaft for secure locking. When sliding or removal is needed, the side members are moved axially apart, allowing the balls to retract from the apertures and eliminating friction, enabling free sliding motion of the inner cylinder on the shaft.
Solution Approach 2:
The inclined surfaces are pre-configured to automatically redirect the ball bearing movement. When axial force is applied to separate the side members, the inclined surfaces immediately guide the balls to retract from the apertures, preventing the balls from interfering with the sliding motion before it begins. This preliminary geometric arrangement ensures smooth transition between locked and sliding states.
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 mechanism provides a secure and durable locking solution that can withstand significant force, maintaining grip regardless of installation direction and preventing damage to the shaft, with the ability to slide freely when needed.
Implementation Method 1
Biasing members, preferably in the form wavy springs which encircle the inner hollow cylinder, and which sometimes may referred to as tension retainers, cause side 1 and side 2 of the locking mechanism to move back together when the clamping action ceases.
Implementation Method 2
Two sets of oppositely angled inclines on the inner surfaces of side 1 and side 2 of the locking mechanism, are aligned with the two rows of apertures in the hollow cylinder. In operation, the balls ride up the inclined surfaces and are caused to project out the apertures due to the bias imparted by the wavy springs.
Implementation Method 3
The balls are biased by a spring and tensioning ring combination to project into the cylinder and to frictionally engage the shaft when the locking mechanisms are in the locked position.
Data Source
AI summary
A lock mechanism which can be placed on a shaft, such as a bar or pole, in either a first direction or second direction, is secured to the shaft using two sets of balls which project out of apertures in an inner cylinder to frictionally engage the shaft. The balls are selectively retractable from their projecting position to allow the inner cylinder to slide on and/or be removed from the shaft. Biasing members, such as wavy springs, bias the two sides of the lock mechanism towards one another. In the locked configuration, the balls are forced by inclined surfaces within the two sides to project outwardly from the inner hollow cylinder. The inclined surfaces are aligned with two rows of apertures in the inner hollow cylinder, and they are inclined in opposite directions. Thus, either way the lock mechanism is installed or placed on the shaft, the balls will project out of the apertures in the inner hollow cylinder and will securely engage the shaft.