Pipe Wrench Extendable Handle Locking for Continuous Length Adjustment
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Solution Overview
Problem
Existing pipe wrenches lack the ability to adjust the handle length continuously and securely within a defined range, limiting their versatility and torque application in confined spaces.
Innovation Solution
An extendable handle mechanism with a channel-lock and friction block system allows the handle to be locked at any point along its length, preventing overextension and ensuring secure grip, using a lever with varying cam surfaces to distribute frictional force for adjustable length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the handle length is fixed, then the wrench structure is simple, but the versatility and torque application in confined spaces is limited
Solution Approach 1:
The handle length is made dynamically adjustable through a telescopic mechanism with a lever-based locking system. The lever can rotate between locked and unlocked positions, allowing the handle to be extended or retracted as needed, transforming a static handle into a dynamic one that adapts to different working conditions.
Solution Approach 2:
The handle length parameter is made variable through the telescopic mechanism. By changing the effective length of the handle, the wrench can be adapted to different torque requirements and confined space constraints, allowing optimization of mechanical advantage based on the specific application.
2Force
If the handle can be extended, then the torque application capability is improved, but the risk of accidental extension or removal increases
Solution Approach 1:
The friction block is positioned between the lever and extendable handle to provide continuous frictional resistance. This frictional force acts as a cushioning mechanism that prevents accidental movement of the handle, securing it firmly in the desired extended position while allowing intentional adjustment when the lever is actuated.
Solution Approach 2:
The friction force, which could potentially cause sticking or difficulty in adjustment, is converted into a beneficial locking mechanism. The friction block creates sufficient frictional resistance to prevent accidental extension or removal, while the lever mechanism provides enough mechanical advantage to overcome this friction when intentional adjustment is needed.
3Reliability
If the lever applies high normal force on the friction block, then the handle is securely locked, but the friction block may wear or deform
Solution Approach 1:
The lever is designed with varying cam surfaces that change the normal force applied to the friction block based on the lever's rotational position. When the lever is in the locked position, the cam surface geometry maximizes the normal force for secure locking. When unlocked, the normal force is reduced, minimizing wear on the friction block during adjustment operations.
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 the user to select the desired handle length within a continuous range, maximizing torque application in confined spaces while preventing accidental extension or removal, enhancing the wrench's versatility and effectiveness.
Implementation Method 1
The lever applies a normal force on the friction block and the friction block distributes the force to the extendable handle such that the extendable handle is secured at a desired length
Implementation Method 2
The lever applies a normal force on the friction block and the friction block distributes the force to the extendable handle
Data Source
AI summary
A pipe wrench is provided with an extendable handle that fits within a cavity of the head. A lever locks the extended length of the extendable handle along a continuous spectrum between a maximum and a minimum extension of the handle. The lever includes cam surfaces. In an unlocked position, the thickness of the lever between the pivot and a friction plate is less than the thickness between the pivot and the friction plate in the locked position. The friction plate is a composite comprising a top lever plate, a midsection, and a concave surface. The lever plate and concave surface include hard, durable materials, and the midsection is a soft elastic material that redistributes frictional forces across the frictional block. The channel-lock prevents inadvertent overextension and/or accidental removal of the extendable handle.