Dual Elevator Car Traction System with Independent Counterweight Braking
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Solution Overview
Problem
Elevator systems with multiple cars in a common shaft face challenges in accommodating drive elements, support, and traction due to the vertically aligned arrangement, particularly in achieving safe and efficient operation at high speeds, as existing solutions do not adequately address the attachment, deflection, and guidance of lower cable assemblies.
Innovation Solution
The system features a first elevator car suspended 1:2 with a deflection pulley arrangement and a counterweight, while the second car is centrally suspended with its own counterweight and lower cable ends guided diagonally, with tensioning devices ensuring symmetric force introduction and preventing counterweight jumping through braking devices when exceeding maximum speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two elevator cars are arranged vertically in a common shaft to improve transport capacity, then productivity increases, but device complexity increases due to difficulty in accommodating drive elements, support and traction elements, and roller arrangements
Solution Approach 1:
The patent combines the support and traction functions into a single integrated means (seilzugmittel) that serves both elevator cars. The first support and traction means is used by both the first and second elevator cars, eliminating the need for separate support systems and reducing overall device complexity while maintaining the ability to operate both cars independently
Solution Approach 2:
The common track serves multiple functions: it provides guidance for both elevator cars, supports the braking devices, and acts as a structural element for the entire system. The braking devices also serve dual purposes by providing both deceleration and positioning functions for the elevator cars
2Speed
If tensioning devices with lower ropes are provided to enable high-speed operation above 2.5 m/s, then speed increases, but device complexity increases due to additional flexible elements and pulleys required for deflection and guidance
Solution Approach 1:
The patent extracts the lower rope arrangement from the traditional pulley-based deflection system and replaces it with a simplified tensioning device that directly tensions the first support and traction means. This eliminates the need for additional flexible elements and pulleys while maintaining the ability to operate at speeds above 2.5 m/s
Solution Approach 2:
The tensioning device acts as an intermediary element that provides the necessary tensioning force to the support and traction means without requiring complex lower rope arrangements. It mediates between the counterweight and the elevator cars, providing the required tensioning function in a simplified manner
3Reliability
If braking devices are introduced to decelerate counterweight and prevent jumping, then safety improves, but device complexity increases due to additional force introduction mechanisms
Solution Approach 1:
The braking devices are integrated with the common track structure, combining the guidance function of the track with the braking function. This eliminates the need for separate braking mechanisms and reduces device complexity while maintaining safety against counterweight jumping at high speeds
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
This configuration allows for independent and efficient operation of multiple elevator cars within a common shaft, ensuring safety and high-speed performance by symmetrically distributing forces and preventing counterweight movement at high speeds.
Implementation Method 1
The lower rope is tensioned by means of a first lower rope tensioning device
Implementation Method 2
The deflection pulley arrangement comprises two deflection pulleys which are attached to the lower area of the first elevator car
Implementation Method 3
An associated counterweight is coupled to the lower elevator car
Implementation Method 4
Both elevator cars are suspended on their own support and traction means and have their own counterweights
Implementation Method 5
The tensioning device for the underropes preferably has a locking effect to prevent the counterweight from jumping when the car safety brakes are applied, to which end the counterweight is decelerated by a reaction force introduced into the hoistway
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The invention relates to an elevator system (10) comprising two elevator cars (K1; K2) arranged one over the other, but that can travel independently of each other. Both elevator cars (K1; K2) are suspended on suspension and traction mechanisms (102; 202) and each coupled to a counterweight (G1; G2). Both elevator cars (K1; K2) have a lower cable (110; 210), wherein the two lower cables (110; 210) are tensioned by separate tension devices. The lower cable (110) of the first, lower elevator car (K1) is fastened to the first elevator car (K1) and the first counterweight (G1). The lower cable (210) of the second elevator car (K2) is guided at the second elevator car and at least one of the two lower cable ends thereof (210.1, 210.2) is secured by a weighted body (214, 224) secured in place with play and/or free-floating.