Ball Joint Door Fixing for Stress Fracture Prevention
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Solution Overview
Problem
Existing door furniture fixing methods are vulnerable to stress fractures when an intruder attempts to lever the exterior plate, leading to potential removal of the locking mechanism.
Innovation Solution
A door furniture assembly using a ball joint fixing system, where fixings on the non-service side door plate are secured with a ball joint that accommodates relative movement, reducing stress on the plate and associated fixings during levering attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fixed rigid fixing system is used to secure door plates, then the structural strength is improved, but the vulnerability to stress fractures during levering attempts increases
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed rigid fixing system with a ball joint mechanism that allows relative movement between the door plates and fixings. The ball joint enables the fixing to rotate and adjust its position dynamically, transforming the static rigid connection into a dynamic articulated connection that can absorb levering forces through controlled movement rather than rigid resistance.
Solution Approach 2:
The patent applies the parameter changes principle by modifying the degree of freedom parameter of the fixing system. The ball joint introduces rotational degrees of freedom that were absent in the rigid fixed system, allowing the fixing to change its orientation and position in response to external forces. This parameter change enables the system to transition from a rigid state vulnerable to stress fractures to a flexible state that accommodates deformation.
2Ease of manufacture
If a rigid fixing system is used, then the ease of manufacture is improved, but the likelihood of stress fracture under stress increases
Solution Approach 1:
The ball joint mechanism transforms the static rigid fixing into a dynamic articulated connection. The fixing remains relatively simple in construction but gains the ability to move and rotate, reducing stress concentration points that would lead to fractures in rigid systems. The movement capability is built into the joint design without significantly complicating the manufacturing process.
3Device complexity
If a fixed fixing system is used, then the device complexity is reduced, but the ability to absorb levering forces is compromised
Solution Approach 1:
The ball joint adds minimal complexity to the fixing system while dramatically improving force absorption capability. The joint consists of a ball element within a socket, allowing rotational movement that absorbs levering forces. This simple mechanical element provides the necessary degrees of freedom to accommodate stress without requiring complex mechanisms or multiple components.
Solution Approach 2:
The fixing system is segmented into distinct components: the fixing body, the ball joint element, and the mounting structure. This segmentation allows each component to perform its specific function - the ball joint specifically handles the absorption of levering forces through controlled movement, while the fixing body maintains the secure connection. The segmentation enables specialized optimization of each part for its intended purpose.
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 ball joint system significantly reduces the likelihood of stress fractures in the exterior door plate, enhancing security by absorbing the force of levering attempts without compromising the locking mechanism.
Implementation Method 1
The at least one fixing seat is a ball joint. The relative movement of the at least a part of the fixing seat and the remainder of the non-service side plate involves a relative movement of two parts of the at least one fixing seat. Preferably a first part of the at least one fixing seat is securable to the non-service-side door plate and a second part is preferably securable to the at least one fixing.
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
A door furniture assembly comprises an internal, service-side, door plate (114), an external, non-service-side, door plate (118) and at least one fixing (120a/b) to secure the two door plates (114,118) on service and non-service faces of a door (110) respectively, wherein the at least one fixing (120a/b) is securable at the non-service side door plate (118) by at least one fixing seat (that is adapted to accommodate relative movement of at least a part of the fixing seat and the remainder of the non-service side plate (118).