Reversible Push Plate Assembly for Emergency Exit Doors
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Solution Overview
Problem
Existing push pad and panic bar mechanisms for emergency exit doors require different handed configurations and additional components to operate on both left and right hand opening doors, and they often require significant force to operate, which can be a barrier for the elderly, disabled, and young children.
Innovation Solution
A push plate assembly that includes a housing with a rotatably coupled push plate, a slide plate, and a drive cam that rotates to drive the bolt mechanism, allowing for reversible operation on either left or right hand doors with reduced operational force through the use of bearings and a crank pin, and enabling greater rotation of the bolt mechanism with less push plate rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single push plate assembly is used for both left and right hand doors, then the quantity of components is reduced and adaptability is improved, but the mechanism complexity increases due to the reversible drive requirement
Solution Approach 1:
The push plate assembly is designed with a reversible drive cam mechanism that can operate on both left-hand and right-hand opening doors using the same single unit. The drive cam can rotate in either direction to drive the bolt mechanism, eliminating the need for separate left-handed and right-handed configurations.
Solution Approach 2:
The drive cam is designed to rotate dynamically in either direction depending on the door opening direction. The cam's rotation direction changes based on which side the door opens, allowing the same assembly to adapt to different configurations without mechanical reconfiguration.
2Ease of operation
If bearings and crank pin are used to reduce operational force, then ease of operation is improved, but device complexity increases
Solution Approach 1:
A crank pin is introduced as an intermediary element between the sliding motion of the push plate and the rotational motion of the drive cam. This crank pin converts the linear sliding force into rotational torque, mechanically advantageously reducing the force required to operate the mechanism.
Solution Approach 2:
Bearings are incorporated at critical rotation points to change the friction parameter, reducing the force required to rotate the drive cam and operate the bolt mechanism. This parameter change directly reduces operational force while maintaining reliability.
3Productivity
If the drive cam rotates more than the push plate, then productivity is improved with greater bolt mechanism rotation, but the mechanism complexity increases
Solution Approach 1:
The crank pin mechanism transforms the single-dimensional linear sliding motion of the push plate into multi-dimensional rotational motion of the drive cam. This dimensional transformation allows the cam to rotate through a greater angle than the push plate's rotation angle, increasing productivity.
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
The solution allows for a single unit to operate on both left and right hand doors without additional components and reduces the force required to actuate the push pad, enhancing usability for all individuals while increasing the assembly's lifespan and meeting European standards for release pressure.
Implementation Method 1
The push plate may be hinged by a pin passing through one or more holes in each of the housing and the push plate
Implementation Method 2
a drive cam arranged to rotate within the housing when driven by the slide plate so as to drive the bolt mechanism
Data Source
AI summary
A push plate assembly (10) that may be used for driving a bolting mechanism is disclosed. The push plate assembly (10) may be included as part of a push pad assembly or panic bar assembly, such as may be fitted to single or multipoint bolt mechanisms, for example, those fitted to emergency exit doors. The push plate assembly comprises a housing (32), a push plate (36), a slide plate (45) and a drive cam (55). The drive cam (55) is arranged to rotate within the housing so as to rotationally drive a bolt mechanism.