Eccentric Arm Mechanism for Sash Opening Force
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Solution Overview
Problem
Existing devices for opening and closing sashes require powerful motors due to low closing or opening forces, especially when modern seals need to be pressed tightly against the frame, and they often have space-consuming designs.
Innovation Solution
A device with an eccentrically and pivotably attached arm that executes a pivoting movement relative to the output element, featuring a Y-shaped arm with two fingers for frame-side engagement and locking, allowing for a direct force introduction and reducing motor torque requirements by repelling the wing from the frame early in the movement phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional spindle drives with X- or Y-scissors are used, then the drives can be installed parallel to the sash frame, but the transmittable forces are low when the scissors are close to the extended position (dead center position)
Solution Approach 1:
The opening/closing movement is divided into two distinct phases: a first partial stroke for repelling the wing from the frame, and a second partial stroke for the remaining movement. This segmentation allows each phase to be optimized independently, with the arm mechanism providing high force during the critical repelling phase without requiring the complex X- or Y-scissors throughout the entire range of motion.
Solution Approach 2:
The arm is designed to perform the repelling action (pushing the wing away from the frame) during the first partial stroke before the sash reaches the dead center position. This preliminary action ensures that the wing is already separated from the frame seals before the scissors approach the extended position, eliminating the need for high forces at the dead center and allowing simpler mechanism design.
2Reliability
If additional locking motors or mechanisms are added to ensure secure locking at dead center position, then reliable locking is achieved, but the device complexity increases
Solution Approach 1:
The arm mechanism automatically performs the repelling function during the first partial stroke, and the locking occurs naturally when the sash reaches the closed position. The system uses its own movement to achieve both the repelling and locking functions without requiring separate dedicated locking motors or complex additional mechanisms.
Solution Approach 2:
The opening/closing drive and the locking function are merged into a single integrated mechanism. The arm and scissors work together to simultaneously achieve the repelling action and the secure locking at the closed position, eliminating the need for separate locking systems while maintaining reliability.
3Force
If powerful motors are used to ensure sufficient opening and closing forces for modern seals, then the sealing force is adequate, but the motor power requirements and device dimensions increase
Solution Approach 1:
The arm performs the repelling action during the first partial stroke before the sash reaches the dead center position. This timing ensures that the wing is pushed away from the frame seals early in the movement, maximizing the sealing force when needed without requiring the motor to overcome high resistance throughout the entire range of motion, thereby reducing overall power requirements.
Solution Approach 2:
The mechanism transitions from a static force application to a dynamic two-phase movement. The arm provides high force during the first partial stroke when repelling the wing, then the scissors handle the remaining movement with lower force requirements. This dynamic approach matches the force application to the specific needs of each movement phase, optimizing motor power usage.
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 simplifies the mechanism, reduces motor power demands, and ensures reliable repulsion of the wing from the frame with minimal dimensions, enhancing the force application position for efficient sash operation.
Implementation Method 1
an arm (8) which is effective between the drive element (6) and the output element (7) and is eccentrically and pivotably attached to the drive element (6) with respect to the output element (7), in particular as a Y-shaped arm with two fingers
Implementation Method 2
The arm (8) executes a pivoting movement relative to the output element (7)... direct force introduction
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The invention relates to a device (4) for opening and/or closing a sash (3) relative to a frame (1), in particular for casement sashes, comprising: a movable drive element (6) for generating a drive movement, an output element (7) connected to the drive element (6) in such a way as to move the sash (3), wherein the drive element (6) performs a partial stroke moving relative to the output element (7) and a working stroke moving together with the drive element (6), wherein the connection between the drive element (6) and the output element (7) comprises a locking mechanism (14) to detachably secure the drive element (6) to the output element (7) at one end of its partial stroke.In order to achieve a simple design with reliable repulsion of the wing (3) from the frame (1) with the smallest possible dimensions and power of the motor (5), an arm (8) is provided which pivots outwards during the partial stroke, which as a result of its pivoting movement supports the output element (7) and the wing (3) against the frame (1) and at the end of its pivoting movement locks it in a rotationally fixed manner relative to the output element (7).