Security Shootbolt Latch Decoupling Mechanism
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Solution Overview
Problem
Existing multipoint locks with shootbolts are vulnerable to forced entry attempts, as the retraction of one latch can lead to the simultaneous retraction of both latches, compromising security.
Innovation Solution
A security shootbolt design featuring an external box-like body with two rotating hook-shaped latches and an actuation slide, where the latches are decoupled to prevent simultaneous retraction, ensuring that one latch remains extended even if the other is forced to retract, utilizing an abutment tooth and recess mechanism to maintain the second latch in the extraction configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two hook-shaped latches are used to prevent forced entry, then security against forcing is improved, but vulnerability to simultaneous retraction attacks increases
Solution Approach 1:
The shootbolt mechanism is segmented into two independent latch systems (first latch and second latch) that are mechanically decoupled. Each latch can be extracted or retracted independently without necessarily affecting the other, so that if one latch is forced to retract, the other remains engaged to maintain security
Solution Approach 2:
An intermediate mechanism (the slide with selective coupling elements) is introduced between the two latches. This intermediary selectively couples or decouples the latches based on their operational state, allowing independent operation while maintaining coordinated control through the actuation rod
2Ease of operation
If latches are mechanically coupled to a common actuation rod, then coordinated operation is improved, but forced retraction of one latch causes simultaneous retraction of both latches
Solution Approach 1:
The mechanical coupling between latches and the actuation rod is made dynamic rather than fixed. The coupling elements can selectively engage or disengage based on the operational requirements, allowing the system to switch between coupled operation (for normal actuation) and decoupled operation (for security against forced retraction)
Solution Approach 2:
Different portions of the actuation rod have different coupling characteristics. The first latch is coupled to a first portion of the rod while the second latch is coupled to a second portion, allowing localized control and independent operation of each latch while maintaining overall coordination when needed
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A security shootbolt (1) for multipoint locks, comprising an external box-like body (2) and two hook-shaped latches (3, 4) that can rotate about a respective pin (5, 6) for fixing to the box-like body (2); the latches (3, 4) are functionally associated with an actuation slide (7) which in turn is integral with an actuation rod (8) of a main lock; the pivoting pin (5) of a first latch (3) is arranged proximate to the external face (9) of the box-like body (2) and to the region ( 10) of entry of the actuation rod (8) of the main lock; the pin (6) of the second latch (4) is arranged proximate to the external face (9) of the box-like body (2) and to the portion (1 1 ) opposite the region (10) of entry of the rod (8); the slide (7) comprises a first end (12) for coupling to the actuation rod (8), an abutment tooth (15) for a shoulder (16) of the first latch (3), a straight section (17) and elements ( 18) for coupling to the second latch (4); the first latch (3) comprises a recess (19) proximate to the shoulder (16) for the entry of the tooth (15) of the slide (7) in the event the first latch (3) is forced to retract in order to break and enter, with consequent temporary decoupling of the first latch (3) from the slide (7) and maintenance of the second latch (4) in the extraction configuration, and vice versa.