Rotating Hook Bolt Lock for Non-Handed Door Installation
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Solution Overview
Problem
Existing mortise locks for hinged security screen doors face complexity in mode conversion, high manufacturing costs, and are often 'handed,' meaning they can only be used on either right-handed or left-handed doors, with linearly reciprocating lock tongues providing inadequate resistance to unauthorized entry attempts.
Innovation Solution
A lock design featuring a rotating hook bolt that can engage with a strike, allowing for non-handed installation and enhanced resistance to unauthorized access, combined with a snib mechanism and cylinder cam system for mode control, and bolt retention means to prevent damage during door closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If linearly reciprocating lock tongues are used, then the lock can be simple in structure, but the lock provides inadequate resistance to unauthorized entry attempts
Solution Approach 1:
The patent employs a rotating hook bolt instead of a linearly reciprocating lock tongue. The hook bolt rotates between an engaged position (extending from the lock body to engage the strike plate) and a retracted position (withdrawn into the lock body). This dynamic rotation provides superior resistance to jimmying and forced entry attempts compared to linear movement, while maintaining reasonable mechanical simplicity through the use of a single rotational degree of freedom.
Solution Approach 2:
The hook bolt features a curved, hook-shaped engagement end that rotates into a cavity in the strike plate. This curved geometry provides mechanical advantage by creating a camming action that resists lateral forcing attempts. The spherical/curved rotation path of the hook bolt allows it to engage and disengage smoothly while providing inherent resistance to unauthorized entry through its geometric configuration.
2Adaptability or versatility
If the lock is designed to be handed (right-handed or left-handed only), then the lock mechanism can be simpler, but the lock cannot be used on both right-handed and left-handed doors
Solution Approach 1:
The lock is designed as a universal, non-handed mechanism that can be installed on both right-handed and left-handed doors without reconfiguration. The rotating hook bolt and strike plate cavity are configured to work together in either orientation. The symmetry of the rotational mechanism allows the same lock body to function correctly regardless of which side of the door the hinges are located on, eliminating the need for separate right-handed and left-handed lock variants.
3Adaptability or versatility
If complex mechanisms are used for mode conversion, then the lock can provide multiple security modes, but the manufacturing cost and assembly difficulty increase
Solution Approach 1:
The patent combines multiple locking modes (passage mode, safety mode, and deadlocked mode) into a single integrated lock mechanism. The rotating hook bolt serves all three modes: in passage mode it can be retracted by the handle; in safety mode it is held engaged by a snib mechanism; in deadlocked mode it is secured by both the snib and a deadlock mechanism. This merging of functions into a unified rotational system reduces the number of separate mechanisms needed compared to traditional multi-mode locks, thereby simplifying manufacturing and assembly.
Data Source
AI summary
A lock includes a bolt having latching and unlatching positions, and a locking component having a locking position in which the bolt is prevented from moving from the latching position to the unlatching position, and an unlocking position in which the locking component does not prevent the bolt from moving. A lock cylinder includes a cam having unlocking and deadlocking positions. A deadlocking component has a disengaging position in which the deadlocking component does not prevent the locking component from moving from its locking position to its unlocking position; and when the locking component is in its locking position, an engaging position in which the deadlocking component prevents the locking component from moving. When the cam is in its unlocking position, the locking component is in its unlocking position and a deadlocking component is in its disengaging position, and conversely when the cylinder cam is in its deadlocking position.