Elevator Screw-Nut Thread Geometry for Smoother Section Joints
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Solution Overview
Problem
Elevators with elongated threaded screws divided into sections often experience irregularities at joints, leading to unpleasant sounds and bumps due to angular misalignment, which are transferred to the elevator platform and occupants.
Innovation Solution
The design modifies the load-supporting flanks of the nut's threads with angled sections that create a tapered space between the screw and nut threads, allowing irregularities to enter without contact, thereby reducing sound and bump transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the threaded screw is divided into multiple screw sections to facilitate transportation and installation, then the ease of manufacture and installation is improved, but thread irregularities and angular misalignment occur at the joints between sections
Solution Approach 1:
The screw is divided into multiple screw sections that can be separately manufactured and then joined together. This segmentation allows for easier transportation and installation while maintaining the functionality of the elongated screw structure.
Solution Approach 2:
The nut is designed with a differentiated thread flank structure where a first flank engages with the screw thread and a second flank is angled relative to the first flank. This local structural differentiation creates a gap between the threaded screw and the nut at the engagement point, which absorbs misalignment and reduces the impact of joint irregularities.
2Manufacturing precision
If high precision is used in producing screw sections, then the manufacturing precision is improved, but the cost and complexity of manufacture increases
Solution Approach 1:
The nut's thread flank is designed with an angled second flank that creates a gap between the screw and nut at the engagement point. This parameter change in the geometric configuration allows the system to tolerate thread irregularities without requiring extremely high manufacturing precision, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The angled second flank of the nut acts as an intermediary element that mediates between the screw thread and the load-bearing first flank. This intermediary structure absorbs the irregularities and misalignments, allowing the system to function smoothly without requiring perfect thread matching.
3Strength
If the nut directly engages the screw threads with full contact, then the load bearing capacity is improved, but the impact from thread irregularities is transmitted to the elevator platform
Solution Approach 1:
The nut is designed with differentiated thread flanks where the first flank bears the load and the second flank is angled to create a gap. This local structural differentiation allows the load-bearing function to be separated from the engagement function, enabling full load contact while preventing impact transmission.
Solution Approach 2:
The angled second flank creates a gap between the screw and nut that acts as a cushioning element before the load is fully transmitted. This pre-designed gap absorbs irregularities and prevents direct impact transmission to the elevator platform, cushioning the effect before it reaches the harmful level.
Data Source
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AI summary
The present invention relates to an arrangement for moving an elevator platform (14) between different levels within an elevator shaft. The arrangement comprises: an elongated screw (20), said screw comprising at least two screw sections (21) joined together and threads (22) arranged around the peripheral surface along the at least two screw sections (21); a nut (30) turnably arranged on the elongated screw (20), said nut is arranged to support the elevator platform, said nut comprises an upper end (31) and a lower end (32) and internal threads (33) corresponding to the threads on the screw extending between the upper and lower end of the nut; and an electrical motor (40) arranged to rotate the nut to move the nut, and the elevator platform, between the different levels along the screw. The load from the elevator platform is supported by a flank (34) of the thread (33) in the nut (30) that is facing downwards and a flank (23) of the thread of the screw (20) that is facing upwards, and a section (S) of the flank (34) of the thread (33) in the nut that is facing downwards in the upper and / or lower end of the nut is angled such that a space between the flank (23) of the thread of the screw (20) that is facing upwards and the flank (34) of the thread (33) in the nut facing downwards is formed.