Sliding Door Catch Mechanism with Cylinder-Piston Deceleration
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Solution Overview
Problem
Existing sliding door systems require significant opening force from operators due to the feeding force of springs, and they lack uniform closing speed control.
Innovation Solution
A sliding door system with a catch mechanism coupled to a feed device featuring a spring energy store and a cylinder-piston unit, which includes a piston disk that adjusts passage cross-sections to control deceleration and acceleration, allowing for uniform closing speed and reduced opening force by utilizing a speed-dependent throttle and tension spring to overcome frictional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a spring feed device is used to close the sliding door, then the closing speed can be controlled, but the opening force required by the operator increases significantly
Solution Approach 1:
The feed device is activated only in a partial stroke range adjacent to the end positions, not throughout the entire door travel. The catch couples to the drive element only when the door is near the closed or open position, allowing the spring to assist closing only during the final approach rather than throughout the entire motion, thereby reducing overall opening force while maintaining controlled closing speed.
Solution Approach 2:
The system transitions from a static spring preload to a dynamic engagement mechanism where the catch selectively couples to the drive element based on door position. This dynamic activation ensures the spring force is applied only when needed for controlled closing, rather than continuously opposing the operator during opening.
2Device complexity
If the passage cross-section in the cylinder-piston unit is kept constant, then the structure is simple, but the closing speed cannot be uniformly controlled throughout the stroke
Solution Approach 1:
The piston disk is designed to dynamically adjust the passage cross-section between the displacement and compensation chambers based on the door's velocity and position. As the door approaches the end position and velocity decreases, the piston disk shifts to increase the passage area, allowing faster fluid equalization and maintaining uniform closing speed throughout the stroke.
Solution Approach 2:
The system changes the flow parameter (passage cross-section area) as a function of door position and velocity. The piston disk's position relative to the cylinder wall varies dynamically, creating a variable orifice that adapts the fluid flow rate to match the required closing speed profile, transitioning from small passage area at high velocity to larger passage area at low velocity.
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 system achieves uniform closing speed and low opening force by effectively managing the tension spring's force to counteract static and rolling friction, ensuring smooth operation and reduced operator effort.
Implementation Method 1
The feed device has a spring energy store forming an acceleration device
Implementation Method 2
The tension force of the tension spring of a minimum effective length that is extended by a quarter of its effective stroke amounts to between 1.5 and 3.5 times the amount of the sum of the static frictional force of the sliding door leaf and the resistance of the cylinder-piston unit
Implementation Method 3
the pressure in the displacement chamber decreases with decreasing velocity. In a threshold range of pressure, the deceleration effect is reduced to a minimum
Implementation Method 4
The minimum passage cross-section is between 0.5 percent and 4 percent of the internal cross-sectional area of the cylinder
Data Source
AI summary
A sliding door system includes a door frame and a sliding door leaf that can move relative thereto. A catch is arranged either on the door frame or on the sliding door leaf, which can be coupled to a drive element of a feed device arranged on the respective other component. The feed device has a spring energy store and a cylinder-piston unit. The cylinder-piston unit has a piston that separates a displacement chamber from a compensation chamber. A passage cross-section between the displacement chamber and the compensation chamber can be changed in a load-dependent manner by a piston disk that can be applied at a piston end side. The tension force of the tension spring of a minimal effective length is between 1.5 and 3.5 times the total static friction force of the sliding door leaf and the resistance of the cylinder-piston unit at the maximum passage cross-section.