Universal Dogging Mechanism with Electronic Latch Retraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dogging mechanisms are limited to specific latching arrangements, lack remote actuation capabilities, and are inefficient in power usage, making them costly and complex to implement across various exit devices with different latch arrangements.
Innovation Solution
A universal dogging mechanism with a progressive blocking element and ratchet-pawl system, combined with an electronic latch retraction device using an electromechanical actuator and linkage mechanism, allowing for remote operation and reduced power consumption by employing mechanical advantage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional dogging mechanisms are used for specific latching arrangements, then the mechanism can effectively prevent latch engagement, but the mechanism lacks versatility and must be customized for each latch type, increasing device complexity and cost
Solution Approach 1:
The patent applies universality by designing a dogging mechanism with a progressive blocking element that can accommodate multiple latch arrangements through a standardized interface. The blocking element can be positioned at various locations along its length to engage with different latch types, allowing a single mechanism design to serve multiple functions across different exit device configurations without requiring customization for each latch type
2Ease of operation
If conventional dogging mechanisms are used without remote actuation, then the mechanism is simple in design, but it lacks the capability for electronic control and remote operation, reducing ease of operation in automated environments
Solution Approach 1:
The patent replaces manual mechanical actuation with an electromechanical actuator that can be controlled remotely or centrally. The actuator converts electrical signals into mechanical motion to position the blocking element, enabling electronic control and remote operation while maintaining the core mechanical dogging function. This substitution allows integration with building access control systems and automated door management
3Extent of automation
If electromechanical actuators are used for latch retraction, then remote control is enabled, but power consumption increases, worsening energy efficiency
Solution Approach 1:
The patent employs periodic action by using the electromechanical actuator only when needed for latch retraction or dogging operations, rather than continuous operation. The actuator is activated intermittently to adjust the blocking element position or retract the latch, then remains inactive, allowing the mechanical system to maintain its state passively. This periodic activation significantly reduces overall power consumption compared to continuous electronic control
4Ease of operation
If conventional latch retention methods are used, then the latch remains engaged, but the latch cannot be remotely retracted, reducing ease of operation for automated exit control
Solution Approach 1:
The patent introduces an intermediary electromechanical actuator that mediates between the control system and the latch mechanism. The actuator serves as a translator, converting electrical control signals into the mechanical force needed to retract the latch against spring pressure. This intermediary component enables remote retraction capability while isolating the complexity of the actuation mechanism from both the latch design and the control system
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 secure, versatile, and energy-efficient operation of exit devices across various latch arrangements, allowing for both manual and remote control of dogging and undogging, with reduced power usage and increased reliability.
Implementation Method 1
a ratchet and pawl configured to prevent movement of the blocking element towards the second unblocking position, where the ratchet includes a plurality of locking regions configured to prevent movement of the blocking element in a plurality of locking positions
Implementation Method 2
an electromechanical actuator, a force input portion configured to receive force from the electromechanical actuator
Implementation Method 3
The force transmitted to the push bar to the move the push bar to the retracted position is between 1.2 and 2 times greater than the force received by the force input portion
Data Source
AI summary
A dogging mechanism for an exit device may include a progressive latching arrangement to allow for dogging at a plurality of positions of a push bar. An electronic latch retraction device may include a camming arrangement configured to provide mechanical advantage when retracting a push bar of an exit device.