Self-Braking Gear Planetary Locking Mechanism
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Solution Overview
Problem
People conveyors like escalators or moving walkways risk uncontrolled movement of conveyance elements when the drive unit or transmission elements fail, leading to safety concerns.
Innovation Solution
A self-braking gear system with a planetary gear mechanism that locks when no torque is provided, activating a braking mechanism to prevent uncontrolled movement by using a movable disk and conical eccentric shafts to engage the braking mechanism, ensuring the chain of conveyance elements is locked in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a braking mechanism is added to prevent uncontrolled movement, then safety is improved, but device complexity increases
Solution Approach 1:
The planetary gear mechanism automatically activates the braking mechanism when no torque is provided via the input shaft. The system self-diagnoses the failure condition and triggers braking without external control signals, eliminating the need for complex sensors and control systems while maintaining high safety.
Solution Approach 2:
The braking mechanism is integrated with the planetary gear mechanism into a single compact unit. The movable disk and brake pads share common structural elements with the planetary gear, reducing overall device complexity while providing both torque transmission and braking functions.
2Volume of stationary object
If a compact braking system is integrated, then space requirements are reduced, but manufacturing complexity increases
Solution Approach 1:
The brake pads and movable disk are nested within the planetary gear structure. The brake pads are positioned between the movable disk and the planetary gear components, allowing the braking system to occupy the same spatial envelope as the torque transmission system without requiring additional external space.
Solution Approach 2:
The planetary gear components serve dual functions: torque transmission during normal operation and activation of the braking mechanism during failure. The movable disk both transmits torque and acts as the actuating element for the brakes, reducing the number of separate manufactured parts.
3Reliability
If the planetary gear locks when no torque is provided, then safety is improved, but torque transmission capability may be affected
Solution Approach 1:
The planetary gear mechanism dynamically transitions between two states: engaged for torque transmission when torque is applied to the input shaft, and locked when no torque is provided. This dynamic behavior ensures that the locking only occurs under failure conditions, not during normal operation, maintaining full torque transmission capability when needed.
Solution Approach 2:
The system uses torque presence as a feedback signal to control the locking state. When torque is detected on the input shaft, the planetary gear remains unlocked for power transmission. When torque is absent, the feedback triggers the locking mechanism, ensuring safety without compromising power transmission during normal use.
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 self-braking gear effectively prevents uncontrolled movement of conveyance elements by integrating a compact braking system that can be easily added to existing people conveyor designs, enhancing safety and reliability without increasing space requirements.
Implementation Method 1
at least one eccentric shaft having a conical surface being formed on at least one of the planets and is configured to lock when no torque is provided via the input shaft
Implementation Method 2
a braking mechanism, which is configured for braking the output shaft
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A self-braking gear (2) comprises: an input shaft (4), an output shaft (6), a braking mechanism (8), which is configured for braking the output shaft (6), and a planetary gear (10). The planetary gear (10), which is connected between the input shaft (4) and the output shaft (6), is configured to activate the braking mechanism (8) in order to brake the output shaft (6), when no torque is provided via the input shaft (4). The self-braking gear (2) may be employed in a people conveyor (50) such as an escalator.