Elevator Car Door Sliding Shoe Guide Mechanism
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Solution Overview
Problem
Alternative elevator systems without counterweights require reducing the weight of car components, including the door leaf, to balance the car's weight, as conventional guide mechanisms are not applicable in these systems.
Innovation Solution
A guide mechanism for the car door featuring a sliding shoe with an extended receptacle that surrounds it on at least three sides, where the sliding shoe has an extension of at least 30% of the door leaf's length, and includes a roller above the door leaf's center of gravity to absorb weight, reducing frictional forces and allowing for a lightweight design with fewer components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional guide mechanisms with guide rollers are used, then stable guidance is achieved, but the weight of the car door increases
Solution Approach 1:
The patent replaces the conventional guide roller mechanism with a sliding shoe mechanism that slides within a receptacle. This substitution eliminates the need for heavy guide rollers while maintaining stable guidance through the sliding action of the shoe against the receptacle walls, thereby reducing the overall weight of the car door.
Solution Approach 2:
The patent extracts and removes the heavy guide roller component from the conventional guide mechanism, retaining only the essential guidance function through the sliding shoe and receptacle arrangement. This extraction of the unnecessary heavy component directly reduces the car door weight while preserving guidance stability.
2Device complexity
If the sliding shoe has a small extension, then the structure is compact, but the door leaf can twist and guidance stability is reduced
Solution Approach 1:
The sliding shoe is designed with an extended structure that spans a significant portion of the door leaf width, creating multiple contact points with the receptacle. This segmentation of the guidance function across multiple points prevents twisting while maintaining compact overall structure.
Solution Approach 2:
The sliding shoe extends in the horizontal dimension (across the door leaf width) to provide multiple suspension points, preventing twisting. This dimensional extension does not increase vertical complexity but provides rotational stability by distributing the door leaf across multiple contact points in the horizontal plane.
3Reliability
If conventional guide mechanisms are used, then guidance is provided, but frictional forces are high requiring larger drives
Solution Approach 1:
The patent replaces the rolling contact mechanism with a sliding contact mechanism that incorporates friction-reducing inserts. These inserts, made of low-friction materials, reduce the coefficient of friction between the sliding shoe and receptacle, thereby reducing the drive force required while maintaining reliable guidance.
Solution Approach 2:
The patent changes the friction parameter by introducing friction-reducing inserts made of specialized low-friction materials. This material parameter change reduces the frictional forces between the sliding shoe and receptacle, allowing for smaller drive motors while maintaining guidance functionality.
4Reliability
If conventional guide mechanisms are used, then the door is supported, but maintenance intervals are short due to wear
Solution Approach 1:
The patent replaces the conventional sliding contact mechanism with one that incorporates friction-reducing inserts. This substitution reduces wear on both the sliding shoe and receptacle surfaces, thereby extending maintenance intervals while maintaining reliable door support functionality.
Solution Approach 2:
The patent uses composite materials or specialized low-friction materials for the friction-reducing inserts. These composite materials provide both low friction for reduced wear and high durability, extending the operational life of the guide mechanism and increasing maintenance intervals while maintaining reliable door support.
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 results in a weight-reduced car door with reduced frictional forces, lower maintenance needs, and a compact design, enabling smoother operation and increased maintenance intervals while maintaining stable guidance and preventing tilting.
Implementation Method 1
The roller serves to absorb at least part of the weight of the door leaf and introduce it into the firmly anchored receptacle. This means that less force is transmitted via the upper sliding shoe, so that the frictional forces between the sliding shoe and the holder are reduced.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a car door (3) for a lift car having a guide mechanism (1) and a door leaf (15). The guide mechanism (1) comprises a sliding shoe (5, 5a) which is connected to the door leaf of the lift car door (3). Furthermore the guide mechanism comprises a receiving part which surrounds the sliding shoe (5, 5a) on at least three sides. The sliding shoe (5, 5a) has, in a sliding direction (11), an extent which corresponds to at least 30% of the extension of the door leaf (15) in this direction.