Surface-Mounted Electric Strike for No-Cut Door Frame Installation

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Solution Overview

Problem

Existing door locking devices, particularly overhead mounted strikes, require extensive modifications to the door frame during installation, leading to increased installation time, cost, and weakened structural integrity, and can result in dangerous situations due to improper latch positioning.

Innovation Solution

A surface-mounted electric strike with a keeper assembly that rotates between latched and unlatched positions, utilizing an actuator assembly to allow for compact installation without cutting the door frame, and accommodating various latch spacings through modular design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard overhead surface mounted strike is used, then the door can be secured in a closed position, but the strike thickness exceeds the latch vertical travel distance causing the latch to fail to clear the upper lip of the cavity

Engineering Contradiction:
Improvedoor securityVSAvoidmanual door opening
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the strike body movable rather than fixed. The strike body can translate vertically along the door frame within a defined range, allowing adjustment of the cavity position relative to the latch. This dynamic positioning ensures the latch can properly engage and disengage from the cavity while maintaining secure door locking.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a prior art electric strike with rotating keepers is used, then the latch can be released without depressing the tubular door handle, but extensive cuts must be made to the door header to provide clearance for keeper rotation

Engineering Contradiction:
Improvelatch release operationVSAvoidinstallation complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent segments the electric strike into separate modular components: a strike body, a keeper assembly, and an actuator assembly. The keeper is rotatably mounted to the strike body rather than requiring header cuts. This segmentation allows the components to be independently positioned and installed, eliminating the need for extensive door frame modifications while maintaining the ability to release the latch electronically.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements nesting by placing the keeper assembly inside the strike body cavity. The keeper rotates within the confined space of the strike body, eliminating the need for external clearance space in the door header. The actuator assembly is also positioned within the strike body, creating a compact integrated unit that mounts to the door frame without requiring extensive cuts.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If extensive cuts are made to the door header to accommodate prior art electric strikes, then adequate clearance is provided for keeper rotation, but the door header structural integrity is weakened and installation time increases

Engineering Contradiction:
Improvekeeper rotation clearanceVSAvoiddoor header structural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

By segmenting the electric strike into separate components that mount within the existing door frame structure, the patent eliminates the need for extensive header cuts. The strike body mounts to the door frame surface, and the keeper rotates within the strike body rather than requiring external clearance, preserving the structural integrity of the door header.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-dimensional mounting approach (requiring header cuts for keeper rotation arc) to a three-dimensional solution where the keeper rotates within the depth of the strike body cavity. This dimensional change allows adequate rotation clearance without compromising the door header structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of manufacture

If a fixed position strike is used, then the installation is straightforward, but the strike cannot accommodate various latch spacings in different door configurations

Engineering Contradiction:
Improveinstallation simplicityVSAvoidlatch spacing accommodation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the strike body position adjustable rather than fixed. The strike body can be positioned at different vertical locations along the door frame within a defined range, allowing adaptation to various latch spacings in double doors, frameless glass doors, and other door configurations while maintaining a relatively simple installation process.

Inventive Principle:
Principle #15Dynamics

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

Enables efficient, cost-effective installation of an electric strike that maintains door security and free egress without damaging the door frame, while adapting to different door latch spacings and ensuring proper latch positioning.

Implementation Method 1

The actuator assembly includes a solenoid and a plunger movably disposed within the solenoid

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

A spring is positioned within the spring housing and is configured for urging the plunger toward the blocking position

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP4293182B1Surface mounted electric strike
Publication Date: 2025.10.22 HANCHETT ENTRY SYSTEMS INC
  • EP4293182B1 patent drawingFigure 1A
  • EP4293182B1 patent drawingFigure 1b~2
  • EP4293182B1 patent drawingFigure 3

AI summary

A surface mounted electric strike for selectively retaining a door latch of a door is provided. The electric strike comprises a housing mounted to a surface of the door frame, wherein the housing defines a cavity configured for receiving the door latch. A keeper is mounted within the housing and movable between a latched position and an unlatched position. The keeper includes a keeper body portion and an extended lobe portion having a terminal end. An actuating assembly is configured for moving between a first mode and a second mode, wherein when the actuating assembly is in the first mode the keeper is prevented from moving toward the unlatched position, and wherein when the actuating assembly is in the second mode the keeper is permitted to move toward the unlatched position.