Rope-Climbing Fall-Arrest Device With Rack-and-Pinion Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fall-arrest devices for rope-climbing activities are bulky and complex due to the use of a swing arm arrangement, leading to increased manufacturing costs and weight, and potential snagging issues.
Innovation Solution
A compact fall-arrest device with a brake wheel mechanism that includes a housing, anchor means, and a spring-biased locking system, allowing the brake wheel to rotate at a nominal speed until a fall occurs, whereupon it locks to arrest the fall, utilizing fewer parts and a two-part frame design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a swing arm arrangement is used in the fall-arrest device, then the device can effectively arrest falls, but the device becomes bulky and heavy
Solution Approach 1:
The patent removes the swing arm component from the device structure. Instead of using a swing arm to connect the brake wheel to the housing, the brake wheel is directly mounted on an axle within the housing, eliminating the unnecessary swing arm and reducing overall device weight and complexity.
Solution Approach 2:
The device is divided into distinct functional modules: a housing containing the brake mechanism, a separately mounted brake wheel on an axle, and a gate assembly. This segmentation allows each component to be optimized independently and reduces the need for connecting structures like swing arms.
2Reliability
If a swing arm arrangement is used in the fall-arrest device, then the device can effectively arrest falls, but the device complexity increases
Solution Approach 1:
The swing arm is completely removed from the device. The brake wheel is directly mounted on an axle that is hinged to the housing, eliminating the swing arm and all its associated connection points, hinges, and mounting structures, thereby reducing component count.
Solution Approach 2:
The functions of the swing arm connection and the brake wheel mounting are merged into a single direct mounting arrangement where the brake wheel is fixed to the axle which is hinged to the housing, reducing the number of separate components needed.
3Reliability
If a swing arm arrangement is used in the fall-arrest device, then the device can effectively arrest falls, but the manufacturing cost increases
Solution Approach 1:
By removing the swing arm component, the patent reduces the number of parts that need to be manufactured, inventoried, and assembled. This simplification directly reduces manufacturing costs while maintaining the fall arrest function through the direct-mounted brake wheel mechanism.
4Ease of operation
If the brake wheel is allowed to rotate freely, then the device can move smoothly along the rope, but the device cannot arrest falls
Solution Approach 1:
The brake wheel is designed with a dynamic locking mechanism that allows free rotation during normal movement but automatically locks when excessive rotation speed is detected during a fall. The spring-loaded pawl engages with the toothed rack only when the brake wheel rotates beyond the nominal rate, providing adaptive behavior.
Solution Approach 2:
The spring-loaded pawl and toothed rack mechanism provides mechanical feedback that monitors the rotation speed of the brake wheel. When the rotation exceeds the nominal rate indicative of a fall, the centrifugal force causes the pawl to engage with the rack, automatically arresting the rotation and preventing fall.
5Ease of operation
If the brake wheel locking means is spring-biased to a stored position, then the device operates smoothly at nominal speeds, but the locking mechanism adds complexity
Solution Approach 1:
The spring-loaded pawl automatically engages with the toothed rack when needed without requiring external activation. The spring bias keeps the pawl disengaged during normal operation, and the centrifugal force during a fall automatically overcomes the spring bias to engage the locking mechanism, making the system self-regulating.
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 device is more compact, easier to manufacture, and reduces the risk of snagging, providing effective fall arrest with a smoother operation and reduced impact on the user during deployment.
Implementation Method 1
the brake wheel locking means being spring-biased to a stored position when the brake wheel is stationary or rotates below the nominal rate during use
Implementation Method 2
the teeth of the brake wheel to progressively bite into the rope and arrest downward movement of the device along the rope
Implementation Method 3
the brake wheel to assume a path of movement further towards the thrust bearing surface such that when rotation of the brake wheel exceeds the nominal rate
Implementation Method 4
the brake wheel axle being drivingly secured at at least one end thereof to a respective pinion having teeth extending radially therefrom, the teeth of the or each pinion being engageable with a respective toothed rack fixed to the inside of the housing
Data Source
AI summary
A fall-arrest device (1,26) for use during rope-climbing activities, the device comprising or including a housing (5) for rotatably receiving therewithin a brake wheel (11,30) supported on an axle (20), the housing including anchor means (3,4) permitting connection of the device to a user thereof, the brake wheel having peripheral teeth (17,29) adapted to, in use, engage with a mid-portion of an anchored safety rope (2), the housing being openable by a gate (5a) through which to receive part of the anchored safety rope and thereafter being closable to trap the safety rope between the teeth of the brake wheel and a rope bearing thrust surface (18,28) on or in the housing, the brake wheel having associated automatic locking means (23,24), preventing rotation of the brake wheel about the axle above a nominal rate of rotation, the brake wheel locking means being spring-biased (14) to a stored position when the brake wheel is stationary or rotates below the nominal rate during use, the brake wheel locking means (24) being movable from the stored position to an operable position in which it engages with one or more locking formations (23) preventing further rotation of the brake wheel about the axle, the brake wheel axle being drivingly secured at at least one end thereof to a respective pinion (13a, 13b) having teeth extending radially therefrom, the teeth of the or each pinion being engageable with a respective toothed rack (12a, 12b,27) fixed to the inside of the housing whereby to permit the brake wheel to assume a path of movement further towards the thrust bearing surface such that when rotation of the brake wheel exceeds the nominal rate and has been arrested, such that when the rate of rotation of the brake wheel relative to the anchored rope exceeds the nominal rate, the axle and brake wheel are progressively driven further towards the thrust bearing surface to thereby cause the teeth of the brake wheel to progressively bite into the rope and arrest downward movement of the device along the rope.