Two-Piece Pawl Assembly for Positive Ratchet Engagement
Solution Overview
Problem
Conventional pawl and ratchet assemblies often experience partial engagement, leading to unwanted motion and potential safety concerns in amusement park rides and other applications, as the pawl tooth may only partially engage with the ratchet tooth, causing the restraint to loosen or jerk during operation.
Innovation Solution
A two-piece pawl assembly with a pivotally mounted upper portion and a pawl arm that includes a tooth for engaging the ratchet teeth, where a spring applies force to ensure full engagement, and non-planar contact surfaces facilitate independent pivoting to avoid partial engagement by changing the direction of contact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-piece pawl assembly is used, then the device complexity is reduced, but the engagement reliability deteriorates due to partial engagement and unwanted motion
Solution Approach 1:
The pawl assembly is divided into two separate pieces: an upper portion that pivots independently and a lower portion (pawl arm) that engages the ratchet. This segmentation allows each component to perform its specific function optimally - the upper portion controls engagement timing while the lower portion provides secure locking, thereby improving engagement reliability without excessive complexity
Solution Approach 2:
The upper portion of the pawl assembly acts as an intermediary between the actuating force and the ratchet engagement. It mediates the engagement process by pivoting to control when and how the pawl tooth contacts the ratchet tooth, ensuring full engagement rather than partial contact, thus improving reliability
2Stability of the object's composition
If the pawl tooth only partially engages with the ratchet tooth, then the ease of operation is improved, but the stability deteriorates due to unwanted motion and restraint loosening
Solution Approach 1:
The pawl assembly incorporates dynamic movement through the pivoting upper portion that allows the pawl to actively engage and disengage from the ratchet teeth. This dynamic mechanism ensures full engagement during locking while allowing controlled operation during unlocking, maintaining both stability and ease of operation
Solution Approach 2:
The spring mechanism applies preliminary force to the pawl assembly, pre-positioning it for full engagement with the ratchet tooth before the locking action occurs. This preliminary positioning ensures that when engagement happens, it is complete and stable rather than partial, preventing restraint loosening
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 achieves full or positive engagement between the pawl and ratchet, enhancing safety by preventing unwanted motion and ensuring the restraint remains securely locked in place during ride operations.
Implementation Method 1
a spring applies force to ensure full engagement
Implementation Method 2
non-planar contact surfaces facilitate independent pivoting to avoid partial engagement by changing the direction of contact forces
Data Source
AI summary
A passenger restraint system is provided for use in vehicles such as ride vehicles used in theme and amusement park rides. The restraint system includes a passenger restraint such as a lap bar, a belt, or an over-the-shoulder restraint includes a locking mechanism for selectively latching the restraint in a desired position. The locking mechanism includes a ratchet connected to the passenger restraint and mounted so as to rotate with movement of the passenger restraint. The locking mechanism also includes a pawl, which is a two piece assembly that includes: (1) a pivotally mounted upper portion; and (2) a pawl arm extending outward from the upper portion. In some embodiments, a first end of the pawl arm is pivotally coupled with the upper portion, and a second end of the pawl arm, distal to the second end, includes a tooth for engaging teeth on a surface of the ratchet.