Arborist Block With Lockable Sheave for Adjustable Friction
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Solution Overview
Problem
Conventional arborist blocks require multiple devices to manage varying loads, with groundsman safety compromised when handling heavy tree sections due to insufficient friction, necessitating an improved device that can selectively provide both free rotation and additional friction.
Innovation Solution
An arborist block with a rotatable sheave that can be locked or unlocked to provide adjustable friction, featuring a sheave lock mechanism with radially extendable locks to prevent rotation and enhance friction when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sheave is free to rotate to allow easy handling of loads, then the ease of operation is improved, but the friction is insufficient to safely handle heavy loads
Solution Approach 1:
The sheave is designed to be dynamically adjustable between free rotation and locked positions. The locking mechanism allows the sheave to transition from a freely rotating state (for easy operation with lighter loads) to a locked state (for safe handling of heavy loads), making the system adaptable to different operational requirements.
Solution Approach 2:
The friction parameter of the sheave is made variable through the locking mechanism. When the locking mechanism engages, it changes the friction parameter from low (free rotation) to high (locked position), allowing the same device to handle both light and heavy loads safely.
2Reliability
If a rigging ring is used to provide friction for heavy loads, then the safety is improved, but the device complexity increases due to requiring multiple devices
Solution Approach 1:
The patent combines the functions of a free-rotating sheave (for easy operation) and a friction device/rigging ring (for safe heavy load handling) into a single integrated arborist block. The locking mechanism enables one device to perform both functions that previously required separate devices.
Solution Approach 2:
The arborist block is designed as a universal device that can handle both light loads (with free rotation) and heavy loads (with locking engaged). This multi-functionality eliminates the need for groundsman to carry and switch between multiple specialized devices.
3Reliability
If the sheave is locked to provide friction, then the safety for heavy loads is improved, but the ease of operation deteriorates due to inability to rotate
Solution Approach 1:
The locking mechanism is designed to be dynamically controllable, allowing the operator to engage or disengage the lock as needed. This dynamic control enables the system to switch between safe locked mode and easy operation mode based on the immediate operational requirements.
Solution Approach 2:
The locking mechanism is designed to be easily operable by the groundsman themselves, allowing them to self-adjust the friction level based on the load conditions without requiring additional tools or complex procedures.
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
Enables safe handling of heavy tree sections by providing adjustable friction, allowing the arborist block to manage loads effectively without requiring multiple devices.
Implementation Method 1
a large rigging ring can be substituted for the arborist block. Because the surface that the rope moves along inside the rigging ring is fixed and does not move, friction must be overcome for the rope to move along the rigging ring
Data Source
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AI summary
An arborist block is provided that includes a front plate (16) having a front plate inner surface (18), a back plate (12) having a back plate inner surface (14), a sheave (20) rotatably coupled to a sheave axle (28) secured between the front plate (16) and back plate and radially centered along a sheave rotational axis (29), and a plurality of sheave locks situated in sheave lock tracks (56) and radially extendable into a plurality of lock receiving recesses (52) in the sheave (20) to prevent rotation of the sheave (20) relative to the sheave axle (28).