Latch Holdback Mechanism for Power-Saving Electronic Release

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Solution Overview

Problem

Existing locksets requiring actuators to actively retract and hold the latchbolt in a retracted position are bulky, expensive, and consume significant electrical power.

Innovation Solution

A lockset mechanism that uses a mechanical holdback mechanism or an electronic holdback mechanism to retain the latchbolt in a retracted position without requiring electrical power for maintenance, utilizing a pawl or solenoid-driven lever to hold the latchbolt, respectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an actuator (motor or solenoid) is used to actively retract and hold the latchbolt, then the latchbolt can be retained in a retracted position, but the device becomes larger, more expensive, and consumes more electrical power

Engineering Contradiction:

Improvelatchbolt retention in retracted positionVSAvoidelectrical power consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The latchbolt is designed to automatically retract and remain held in the retracted position through its own mechanical spring force, without requiring external actuator power. The spring-loaded mechanism self-maintains the retracted state, eliminating continuous electrical energy consumption while preserving the desired operational function.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the electronic actuator system (motor/solenoid) with a purely mechanical spring-based holdback mechanism. This substitution eliminates the need for electrical power to maintain latchbolt retraction, resolving the contradiction between operational capability and energy consumption by using passive mechanical energy storage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If an actuator (motor or solenoid) is used to actively retract and hold the latchbolt, then the latchbolt can be retained in a retracted position, but the device becomes larger and more expensive

Engineering Contradiction:

Improvelatchbolt retention in retracted positionVSAvoidactuator size and cost

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The latchbolt mechanism is designed to be self-sustaining through its spring-loaded construction, eliminating the need for complex external actuators. The spring mechanism automatically maintains the retracted position without requiring motors, solenoids, or associated electronic control systems, thereby reducing device complexity and cost.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex electronic actuator systems with a simple mechanical spring-based holdback mechanism. This substitution dramatically reduces device complexity and component count while achieving the same functional outcome of retaining the latchbolt in a retracted position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If a mechanical holdback mechanism is used to retain the latchbolt, then power consumption is reduced, but the mechanism requires manual actuation to retract the latchbolt

Engineering Contradiction:

Improveelectrical power consumptionVSAvoidmanual actuation requirement

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The spring-loaded holdback mechanism serves multiple functions: it automatically holds the latchbolt in the retracted position to enable door opening, and it simultaneously provides the force necessary to retract the latchbolt when the handle is actuated. This multi-functionality eliminates the need for separate actuators and maintains ease of operation while reducing power consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The spring mechanism is pre-loaded to automatically perform the latchbolt retraction action when the handle is actuated, eliminating the need for manual intervention. The preliminary spring compression stores energy that is automatically released to retract the latchbolt, maintaining ease of operation without requiring additional manual actuation steps.

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

Reduces power consumption and costs by eliminating the need for large actuators, while maintaining the latchbolt in a retracted position for easy door opening without manual actuation.

Implementation Method 1

A spring may be engaged to the holdback and the case such that the spring biases the holdback to the release position

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

In response to receiving the unlock command, the electronic actuator performs a first operation, including moving a holdback from a release position to a hold position

Methodology Applied

Scientific EffectSolenoid: Solenoid

Data Source

PatentUS20250230687A1Latch holdback with electronic release

Publication Date: 2025.07.17 SCHLAGE LOCK CO LLC

AI summary

A method for operating a lockset generally includes transmitting an unlock command to an electronic actuator in response to receiving an unlock signal. In response to receiving the unlock command, the electronic actuator performs a first operation, including moving a holdback from a release position to a hold position. In response to actuation of a manual actuator, a latchbolt is moved from an extended position to a retracted position. The holdback in the hold position retains the latchbolt in the retracted position.