Thread Pairing Energy Absorption for Window Sash Safety
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Solution Overview
Problem
Existing security devices for window or door sashes, which rely on a rope for energy absorption during extreme conditions, may fail to effectively manage high kinetic energy generated by heavy sashes, potentially causing damage due to incomplete energy dissipation.
Innovation Solution
A safety device featuring a thread pairing with a threaded bolt and sleeve, where the threads are designed to fail continuously during the fall, allowing for efficient energy absorption through helical interaction and material differences to prioritize deformation and energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rope is used to secure the sash outside the target movement space, then the sash is prevented from falling to the impact area, but the rope may fail to absorb sufficient kinetic energy generated by very heavy sashes in extreme weather or break-in situations
Solution Approach 1:
The energy absorption function is segmented from the rope and implemented through a dedicated thread pairing mechanism. The thread pairing consists of a threaded bolt and threaded sleeve that can fail in a controlled manner to absorb kinetic energy, while the rope maintains its function of preventing the sash from falling to the impact area. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The invention uses a composite approach by combining the rope (flexible, high-tensile-strength material) with a thread pairing mechanism (metallic components with controlled failure characteristics). The rope provides reliable security and fall prevention, while the thread pairing provides controlled energy absorption through thread deformation and failure. This composite system addresses both the reliability and energy absorption requirements.
2Loss of energy
If the thread pairing is designed to be weak for energy absorption, then kinetic energy is effectively dissipated during the fall, but the thread may fail before the sash comes to a complete stop
Solution Approach 1:
The thread pairing is designed to provide continuous energy absorption throughout the entire fall path of the sash. The helical thread geometry ensures continuous interaction between the threaded bolt and sleeve during the fall, dissipating kinetic energy continuously rather than in discrete stages. This continuous action maintains securement of the sash until it comes to a complete stop, preventing any sudden releases or bounces.
Solution Approach 2:
The invention intentionally designs the thread pairing to fail in a controlled manner, converting the potentially harmful uncontrolled failure into a beneficial energy absorption mechanism. The thread failure is not a defect but a designed feature that dissipates kinetic energy safely. The helical thread geometry ensures that this failure process occurs continuously and controllably throughout the fall, transforming the harmful kinetic energy into beneficial thread deformation and heat.
3Loss of energy
If the thread pairing interacts over the entire circumference during the fall path, then energy is dissipated continuously over many threads, but the device complexity increases
Solution Approach 1:
The invention achieves continuous energy dissipation by optimizing the geometric parameters of the thread pairing, specifically the helical angle and pitch of the threads. By carefully selecting these parameters, the thread interaction occurs continuously over the entire fall path without requiring complex additional components. The parameter optimization allows simple cylindrical threaded components to provide the desired continuous energy absorption behavior.
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 provides a highly effective and simple security device that ensures complete kinetic energy dissipation during a sash's fall, preventing damage by ensuring the thread pairing fails in a controlled manner, maintaining the sash's securement until it comes to a stop.
Implementation Method 1
The courses of the external thread and the internal thread extend in a helical/screw-shaped manner around a central thread axis. This results in the radially inward-facing flanks of the external thread and the radially outward-facing flanks of the internal thread interacting with one another over their entire circumference, specifically during the entire fall path of the wing and during the relative movement of the thread partners along the central thread axis.
Implementation Method 2
at least one of the threads fails and absorbs energy in a continuously effective thread deformation range
Data Source
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AI summary
The invention relates to a locking device (20) for a sash (14) of a window or door assembly (10), in which the sash is mounted on the frame so as to be movable about at least one axis (16) within a defined movement range, wherein the locking device comprises: a first fitting (22) for connection to the frame, a second fitting (24) for connection to the sash, a cable (26) which is connected to the first fitting and to the second fitting and is only effective for transferring the weight of the sash to the frame and securing the sash to the frame when the sash is positioned outside the defined movement range, and an energy absorption device (28) for absorbing kinetic energy of the sash, wherein the energy absorption device comprises: first and second threaded partners with a threaded bolt and with a threaded sleeve,wherein a first thread partner is assigned to one of the fittings and a second thread partner to the cable, wherein an external thread of the threaded bolt and an internal thread of the threaded sleeve are designed such that - if the wing is arranged outside the intended movement range - at least one of the threads fails and absorbs energy in a continuously effective thread deformation range.