Catch Plate Bolt Restraint for Smooth Door Closure

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Solution Overview

Problem

Existing bolting mechanisms fail to effectively restrain bolts in the retracted position when a door is open, leading to issues such as the bottom bolt dragging on the floor and other bolts interfering with the door frame during closure.

Innovation Solution

A bolt restraint mechanism featuring a catch plate that pivots to pinch or grip the bolt, with a release trigger that allows the catch plate to pivot away from the bolt when depressed, enabling secure restraint without modifying the bolt's shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prior art restraint mechanism with blades and notches is used, then the bolt can be restrained in reverse motion, but the bolt requires modification with notches or arrests which increases manufacturing complexity

Engineering Contradiction:

Improvebolt restraint reliabilityVSAvoidbolt manufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of modifying the bolt with notches and having blades engage those notches, the invention inverts the approach by providing a smooth, unmodified bolt and using a catch plate with an aperture that actively engages the smooth bolt surface. The restraint mechanism becomes the active element rather than the passive bolt modification.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The bolt surface remains uniform and homogeneous without notches, arrests, or other discontinuities. The catch plate aperture provides the necessary engagement feature while the bolt itself maintains its simple, homogeneous cylindrical form, improving ease of manufacture.

Inventive Principle:

Principle #33Homogeneity

2Reliability

If the catch plate is biased to pivot towards the bolt, then the restraint surface pushes against the bolt to restrain movement, but the mechanism requires a spring or biasing element which increases device complexity

Engineering Contradiction:

Improvebolt restraint reliabilityVSAvoidrestraint mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A spring element provides a biasing force that pushes the catch plate towards the bolt, creating a reliable restraint. The spring acts as a counterbalancing force that ensures the catch plate maintains contact with the bolt throughout operation, compensating for wear and positional variations.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The spring-biased catch plate system is self-regulating, automatically maintaining the restraint force through the spring's inherent elasticity. The mechanism self-adjusts to bolt position variations and wear without requiring external control systems.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If the catch plate aperture is slightly larger than the bolt cross-section, then the bolt can pass through freely when released, but the restraint grip is reduced compared to a tighter fit

Engineering Contradiction:

Improvebolt release smoothnessVSAvoidrestraint grip force

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The aperture is sized to provide optimal local engagement characteristics - slightly larger than the bolt cross-section to allow smooth passage during release, while the biased catch plate maintains local contact pressure at the engagement points to preserve restraint grip force.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The spring bias预先 positions the catch plate to engage the bolt before the bolt reaches any potential obstruction points, ensuring continuous restraint. The preliminary engagement allows smooth operation while maintaining force through the pre-loaded spring.

Inventive Principle:

Principle #10Preliminary action

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 ensures the bolt remains securely restrained in the retracted position until the door is closed, preventing interference and ensuring smooth operation.

Implementation Method 1

the catch plate biased to pivot or rotate such that a restraint surface of the aperture pushes against the bolt to restrain movement of the bolt

Methodology Applied

Scientific EffectMechanical bias (spring force): Spring

Implementation Method 2

a release trigger arranged such that when depressed the release trigger pushes against the catch plate to pivot releasing the restraint surface from pushing against the bolt

Methodology Applied

Scientific EffectMechanical force application: Mechanical Force

Data Source

PatentUS12559984B2Bolt restraint

Publication Date: 2026.02.24 SURELOCK MCGILL

AI summary

A bolt restraint mechanism for restraining a bolt of a bolting mechanism. The bolt restraint mechanism includes a bolt moveable between thrown and retracted positions and a catch plate having an aperture through which the bolt extends. The catch plate is biased to pivot such that a restraint surface of the aperture pushes against the bolt to restrain movement of the bolt. A release trigger is arranged such that when depressed the release trigger pushes against the catch plate to pivot thereby releasing the restraint surface from pushing against the bolt to release the bolt. The catch plate may be biased such that when the restraint surface pushes against the bolt to restrain movement of the bolt, the catch plate is non-orthogonal to the bolt.