Tubular Lock Key Gravity Ejection for Child Safety
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Solution Overview
Problem
Food freezer locks often retain operating keys in their keyways, posing a risk of child entrapment as children may misuse the keys, and existing solutions are either complex, costly, or unreliable.
Innovation Solution
Modifying tubular locks and keys to utilize the force of gravity by loosening the fit, eliminating interengaging formations, and making keys heavier and longer, ensuring keys self-eject from keyways unless held, with enhanced key design requiring proper orientation for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If keys are snugly received and retained in keyways, then ease of operation is improved, but safety deteriorates due to risk of child entrapment
Solution Approach 1:
The patent inverts the traditional key retention approach by designing keys and keyways that actively promote key ejection rather than retention. The keyway is configured with a stop that prevents the key from being fully inserted, and the key is designed with a bow that engages this stop to cause the key to drop out when released, thereby preventing children from accessing the lock mechanism.
Solution Approach 2:
The patent changes the dimensional parameters of the key and keyway interface. Specifically, the keyway stop is positioned at a distance from the rear face of the lock body that is less than the length of the key, creating a gap that allows the key to be partially inserted but not retained. This parameter change ensures the key can be inserted for operation but will eject when released.
2Object-affected harmful factors
If keys are made heavier and longer, then safety is improved by ensuring key ejection, but weight and complexity increase
Solution Approach 1:
The patent employs self-service by utilizing the force of gravity and the mechanical interaction between the key and keyway stop to automatically eject the key without requiring additional mechanisms or user action. The key's own weight and the geometric configuration of the keyway stop work together to cause the key to drop out when released, eliminating the need for springs, magnets, or other active ejection mechanisms.
3Object-affected harmful factors
If interengaging formations are eliminated, then key ejection is improved, but reliability of key operation may deteriorate
Solution Approach 1:
The patent segments the key and keyway into distinct functional zones: the key blade for insertion and operation, the keyway passage for guiding the key, and the keyway stop for preventing full insertion and promoting ejection. This segmentation allows each component to perform its specific function independently, ensuring reliable key operation while maintaining safety through controlled ejection.
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 solution effectively prevents keys from being inadvertently or deliberately left in locks, enhancing safety by ensuring keys cannot be easily accessed or used improperly, while maintaining low production costs.
Implementation Method 1
the approach utilized by the present invention calls for the operating keys and the keyways of tubular locks to be cooperatively configured so optimal use can be made of the force of gravity to cause the operating keys to drop from the keyways of the tubular locks unless the keys are being held in the keyways of the locks
Data Source
AI summary
A tubular lock and its operating key have safety features that render the lock and key well suited for use with food freezer appliances and the like where the keyway of the lock extends horizontally. The tubular portion of the operating key, and the keyway of the tubular lock are cooperatively configured so a key inserted into the keyway of the lock fits quite loosely and is minimally supported even when fully inserted. The graspable bow of the operating key is made unusually long causing the center of gravity of an inserted operating key to be spaced far from the front face of the lock—so the weight of the loosely fitting and minimally supported operating key levers the graspable bow downwardly, causing the key to drop from the keyway unless being held in the keyway. Gravity is optimally used to effect key ejection.