Casement Window Operator Lockout Mechanism
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Solution Overview
Problem
Casement window operators tend to pivot back to the closed position during operation, especially under heavy loads, due to the misalignment of the knob's axis and the handle's axis of rotation, causing instability and difficulty in maintaining the open position.
Innovation Solution
Incorporating a lockout feature with a biased actuator that engages with a hub to prevent folding from the open to the closed position, allowing the handle to be locked in the open position until manually overridden, and similarly preventing movement from the closed to the open position, ensuring stability during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a folding handle is used for the casement window operator, then the handle can be folded to lie along the base for a compact appearance, but the handle tends to pivot back to the closed position during operation due to misalignment between the knob axis and handle rotation axis
Solution Approach 1:
A lockout feature is introduced as an intermediary mechanism between the handle and hub. This lockout feature includes a protrusion that engages with a recess in the hub when the handle is in the open position, preventing the handle from pivoting back to the closed position during operation. The lockout feature acts as a mediator that maintains the handle's intended position without requiring the user to constantly counteract the destabilizing forces.
2Length of moving object
If the handle is designed to pivot about 135° between closed and open positions, then the handle achieves sufficient range of motion for operation, but the misalignment of axes causes the handle to rotate back to closed position under heavy input loads
Solution Approach 1:
The lockout feature applies preliminary anti-action by engaging the protrusion with the recess in the hub before the handle can pivot back to the closed position. This preventive mechanism counteracts the destabilizing forces created by heavy input loads and wrist action on the knob, maintaining the handle in the open position throughout the window operation.
3Ease of operation
If the knob is disposed at the distal end of the handle with its axis not in the same plane as the handle rotation axis, then the handle can be operated with wrist action, but this creates forces that pull the handle back to the closed position
Solution Approach 1:
The lockout feature serves as an intermediary that blocks the force transmission path from the knob to the handle pivot point. When the user applies wrist action to the knob, the lockout feature's engaged protrusion prevents this force from causing the handle to pivot back to the closed position, allowing convenient operation without the harmful side effect.
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 lockout feature effectively maintains the handle in the desired position, preventing unintended pivoting and allowing for smooth operation of the window sash, enhancing user control and reducing the risk of accidental closure.
Implementation Method 1
The biasing element may be disposed between the back wall of the cavity and the distal end of the actuator for biasing the actuator towards engagement with the hub
Data Source
AI summary
An operator for a casement window is disclosed which includes a hub that frictionally receives a spindle. The hub is pivotally connected to a proximal end of a pivoting handle. The hub is disposed within a cavity that extends through the proximal end of the handle and terminates at a back wall. The cavity partially accommodates a biasing element, an actuator and the hub. The biasing element is disposed between the actuator and the back wall and biases the actuator towards the hub. The hub includes at least one open position recess and open position protrusion and the actuator includes a complementary protrusion and a recess wherein the protrusion is received in the at least one open position recess of the hub and the recess of the actuator receives the at least one open position protrusion of the hub when the handle is pivoted to the open position.