Compact Electric Strike with Dual Spring Segmentation

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Solution Overview

Problem

There is a need for electric strikes that are compact, reliable, and offer programmable operation with enhanced efficiency, long life, and improved construction and operation, addressing the limitations of existing electric strikes in size reduction and functionality.

Innovation Solution

The electric strike design incorporates a longitudinally elongated carrier with a solenoid, slider link, trip lever, actuating arm, blocking arms, and spring elements, allowing for both fail secure and fail safe configurations, enabling secure locking and unlocking mechanisms with compact element placement and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the electric strike uses a single spring element, then the structure is simpler, but it cannot provide both fail secure and fail safe configurations

Engineering Contradiction:
Improveprogrammable operation capabilityVSAvoidspring element configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single spring element is segmented into two separate spring elements (first spring element and second spring element) that can be independently positioned and configured. This segmentation allows the system to provide both fail secure and fail safe configurations by selectively engaging different spring elements, thereby achieving programmable operation capability while maintaining manageable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic reconfigurability by allowing the spring elements to be positioned at different locations along the plunger axis. The system can dynamically switch between fail secure and fail safe modes by adjusting the positioning and engagement of the spring elements, enabling adaptability without requiring a completely different mechanical structure for each mode

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the spring elements are positioned close together, then the device is more compact, but the plunger cannot effectively compress both springs sequentially

Engineering Contradiction:
Improveoverall device sizeVSAvoidplunger compression sequence
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent resolves the spatial conflict by utilizing the longitudinal dimension along the plunger axis. The first and second spring elements are positioned at different locations along this axis, allowing sequential compression by the plunger. This dimensional arrangement enables both springs to be compressed in sequence while maintaining a compact overall device footprint, as the springs are arranged linearly rather than requiring lateral space

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

3Speed

If the second spring element has a higher spring rate, then the plunger returns faster in fail safe mode, but the force required to compress it is greater

Engineering Contradiction:
Improveplunger return speedVSAvoidcompression force
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The first spring element with the lower spring rate performs a preliminary compression action during plunger movement, absorbing initial force and enabling the plunger to reach the second spring element. This preliminary action reduces the peak force requirement for compressing the second, higher-rate spring element, while still achieving fast plunger return when needed in fail safe mode

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

This design enables a single mechanism to provide both fail secure and fail safe door operation, ensuring secure locking with power on and safe unlocking with power off, enhancing reliability and compactness while maintaining efficient door operation.

Implementation Method 1

a mechanism including a longitudinally elongated solenoid supported by the carrier, the solenoid having a longitudinally movable plunger

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

there are first and second spring elements having positions for sequentially resisting plunger axial movement

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3514303B1Compact electric strike with preload release capability
Publication Date: 2021.04.21 HANCHETT ENTRY SYSTEMS INC
  • EP3514303B1 patent drawingFigure 1
  • EP3514303B1 patent drawingFigure 2~3
  • EP3514303B1 patent drawingFigure 4

AI summary

In a door strike for captivating and releasing a door bolt, the combination comprising a longitudinally elongated carrier, a longitudinally elongated solenoid supported by the carrier, the solenoid having a longitudinally movable plunger, a trip lever pivo tally supported in or on the carrier, a laterally extending actuating arm pivotally supported in or on the carrier to be pivoted as the plunger moves longitudinally in response to solenoid energization, thereby to pivot the trip lever, a generally longitudinally extending blocking arm or arms pivotally supported in or on the carrier to be released for pivoting when the trip lever is pivoted, and a door bolt retainer or retainers pivotally supported in the carrier to be released for pivoting when the blocking arm or arms are released for pivoting, thereby to release the door bolt from captivation, for movement with the door. Dual springs are compressed by the plunger in response to solenoid energization. A strut on the plunger engages solenoid structure upon plunger retraction to prevent wear or peening of the plunger.