Platform Elevator Drive Nut Thread for Quiet Screw Transitions
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Solution Overview
Problem
Platform elevators experience noise and discomfort due to play and wear issues between threaded screw sections, particularly when the upper screw section is overturned, causing uneven interfaces that lead to unpleasant noise and chocks during the movement of the elevator platform.
Innovation Solution
A drive nut with a decreasing width nut thread lower flank, designed to smoothly engage with the screw thread interface, featuring a conical portion that adapts to the irregularities between screw sections, and manufactured with a lower hardness than the screw to facilitate controlled wear, ensuring smooth operation and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional drive nut with uniform thread width is used, then manufacturing is simple, but noise and discomfort occur due to impact at screw section interfaces
Solution Approach 1:
The drive nut features a thread lower flank with varying width: a first portion with nominal width and a second portion with reduced width. This local variation in geometry allows the reduced width portion to better conform to the interface between screw sections, reducing impact and noise when transitioning between sections, while maintaining the simplicity of conventional threads in the majority of the engagement length.
2Reliability
If drive nut hardness is increased to reduce wear, then durability improves, but adaptation to interface irregularities becomes difficult
Solution Approach 1:
The drive nut is designed with controlled wear characteristics that allow the thread lower flank to gradually adapt to interface irregularities between screw sections. The varying width geometry of the thread lower flank facilitates this adaptation process, enabling the nut to conform to minor misalignments while maintaining sufficient hardness for long-term durability and wear resistance.
3Ease of operation
If threaded screw sections are joined with male/female joints, then assembly is enabled, but play occurs between thread ends causing impact
Solution Approach 1:
The drive nut's thread lower flank is pre-configured with a varying width profile that anticipates and compensates for potential play or misalignment at screw section interfaces. This preliminary geometric adaptation allows the nut to smoothly engage with the interface between joined screw sections, preventing impact and noise that would otherwise result from the male/female joint configuration.
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 drive nut that effectively reduces noise and wear by adapting to the irregularities between screw sections, ensuring smooth operation and prolonged lifespan of the elevator platform, while maintaining high vertical speed at low rotational speeds.
Implementation Method 1
The width (wl) of the nut thread lower flank 56 decreases within the upper conical portion 58... This facilitates smooth cutting of the underside of lower thread flank against the edge-formed interface and adapts the shape of the thread lower flank to the interface between the screw segments
Implementation Method 2
This facilitates smooth cutting of the underside of lower thread flank against the edge-formed interface... The drive nut 50 is manufactured from a metal material which has a hardness lower than the hardness of the threaded screw
Data Source
Figure 1a~2b
Figure 3~4b
Figure 5a~5c
AI summary
The present disclosure relates to a drive nut (50) for moving a platform (14) of a platform elevator (10), wherein the width (wl) of a nut thread lower flank (56) decreases in the vicinity of an upper nut end (51) in direction from a lower nut end (52) towards the upper nut end (51). Thereby, wear of the underside of the nut thread lower flank (56) against an irregularity between adjacent platform elevator screw sections (20a, 20b; 61a, 61b) is facilitated. The present disclosure further relates to a platform elevator, to a method of adapting a platform elevator drive nut (50), to the use of a drive nut (50), and to an arrangement of a drive nut (50) and a threaded screw (60).