Pre-hung Door Retention Device Tool-Free Installation

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Solution Overview

Problem

Existing temporary door latch devices for pre-hung door and casing units require tools for installation and removal, can damage the door or casing, and are not self-aligning, necessitating removal before installation.

Innovation Solution

A temporary door latch device with a tubular body receivable in the door lock cylinder and latch openings, featuring a male portion with teeth and an elongated engagement portion that locks and unlocks without tools, allowing for tool-free installation and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fasteners (straps, nails) are used to hold the door and casing together during shipping, then the door and casing are securely retained, but the door or casing may be damaged and the fasteners must be removed before installation

Engineering Contradiction:

Improveretention securityVSAvoiddoor damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The retention device is nested within the door structure, with the tubular body received in the door lock cylinder opening and the male portion received in the latch bolt opening. The door itself becomes part of the retention device structure, eliminating the need for external fasteners that could damage the door or casing.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The door and casing serve themselves by using their own structural features (lock cylinder opening and latch bolt opening) to accommodate the retention device. The retention device utilizes the existing openings in the door and casing, making the door and casing integral to the retention system rather than requiring separate fastening elements.

Inventive Principle:

Principle #25Self-service

2Reliability

If traditional fasteners are used to secure the door during shipping, then the door is held in position, but the fasteners must be removed before hardware installation

Engineering Contradiction:

Improvetransportation securityVSAvoidinstallation convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The retention device is extracted from the door and casing after serving its purpose during shipping. The device is specifically designed to be removed after the door and casing are installed in the door opening, leaving no remnants on the door or casing and requiring no additional removal steps before hardware installation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The retention device is designed as a temporary, disposable component that serves its function during shipping and then is removed and discarded. It is not intended for permanent installation, making it ideal for temporary retention applications where the device itself can be discarded after use.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If existing temporary latch devices are used, then the door can be secured during shipping, but tools are required for installation and removal

Engineering Contradiction:

Improvedoor retentionVSAvoidtool-free installation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The retention device replaces complex mechanical fastening systems with a simple insertion and removal mechanism. The tubular body and male portion can be inserted and removed by hand without requiring tools, while still providing secure retention during shipping through the interlocking geometry of the components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If existing temporary latch devices are used, then the door can be held together, but the devices are not self-aligning and require precise positioning

Engineering Contradiction:

Improvealignment accuracyVSAvoidself-aligning capability

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The retention device uses asymmetric geometry to achieve self-alignment. The tubular body is configured to be received in the door lock cylinder opening with specific dimensional relationships, and the male portion has a base larger in diameter than the latch bolt opening. This asymmetric design guides the components into proper alignment during insertion without requiring precise pre-positioning.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The retention device creates an equipotential alignment system where the tubular body, male portion, and engagement portion work together with specific dimensional relationships. The base of the male portion acts as a stop that naturally positions the component correctly within the latch bolt opening, eliminating the need for complex alignment mechanisms.

Inventive Principle:

Principle #12Equipotentiality

Data Source

PatentUS11686135B1Pre-hung door and casing retention device

Publication Date: 2023.06.27 SMITH B JACK

AI summary

A pre-hung door and casing retention device and a method of latching and unlatching a pre-hung door and casing. The door includes a tubular body configured to be receivable in a door lock cylinder opening and a door latch opening. A male portion has an extending post with a plurality of teeth extending from at least one side of said post, the male portion receivable in a latch bolt opening and the door latch opening. An elongated engagement portion has a first end fastened in the tubular body, an opposed second end extending from the tubular portion and a protrusion engaging teeth on the male portion when inserted into the tubular portion and wherein the protrusion is disengaged from the teeth when a withdrawal force is exerted on the engagement portion.