Tensioner Gear Transmission With Friction Locking Against Reverse Operation
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Solution Overview
Problem
Existing tensioning devices, such as load binders and turnbuckles, pose safety hazards due to unexpected reaction forces and mechanical reversals, leading to injuries, and lack efficient torque conversion and friction retention mechanisms.
Innovation Solution
A power transmission system with a driving gear and a driven gear mounted on a shaft, featuring a lubricant reservoir and thrust rings to constrain the support boss, providing mechanical advantage and maintaining tension without reverse operation, and accepting torque inputs from various tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a lever is used to gain mechanical advantage in tensioning devices, then the tensioning force is increased, but reaction forces accumulate in the lever causing safety hazards and unexpected flailing
Solution Approach 1:
The patent introduces a gear mechanism as an intermediary between the input force and the tensioning element. The gear system (including a pinion gear and a rack gear) mediates the force transmission, converting rotational motion into linear tensioning force while distributing reaction forces through the gear teeth engagement, thereby preventing force accumulation in a single lever component.
2Force
If the pitch of a threaded member is selected with a steep helix angle to provide mechanical advantage, then the tension force is increased, but the mechanism can overhaul in reverse causing the threaded member to pull out
Solution Approach 1:
The patent utilizes friction as a beneficial force to prevent reverse overhauling. The gear mechanism is designed with intentional friction between meshing teeth and between the rack gear and the threaded member. This friction, which would normally be considered a loss, is harnessed to maintain the tensioning force and prevent the mechanism from reversing under load, thereby converting a harmful effect into a useful locking mechanism.
3Force
If multiple threads are used in the tensioning mechanism, then the mechanical advantage is increased, but the mechanism becomes more susceptible to unwanted reverse operation
Solution Approach 1:
The gear mechanism serves as an intermediary that decouples the multiple threaded members from direct rotational input. Each threaded member engages with the rack gear independently, but the rack gear translates their combined effect into unified linear motion. This intermediary arrangement allows multiple threads to provide increased mechanical advantage while the gear friction prevents coordinated reverse operation of all threads simultaneously.
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 system ensures safer operation by maintaining proportional force feedback, reducing the risk of accidents, and effectively converting torque into high tensile forces for secure load binding and positioning, while preventing unwanted mechanical reversals and maintaining tension until released.
Implementation Method 1
the driving gear includes a lubricant reservoir and a lubricant passage communicating to the end face of the support boss in contact with the floor of the groove
Implementation Method 2
large rotations at low torque may be exchanged through helical interfaces to produce high tensile forces in related shaft components
Implementation Method 3
It is therefore another objective of the invention to afford sufficient friction so that once its components are tightened under load, the tension developed is preserved until the user loosens the device
Data Source
AI summary
A power transmission for tensioners such as load binders and turnbuckles includes a driving gear and a driven gear mounted on or part of a driven shaft. The driving gear includes an axially protruding support boss which is received within a groove in the driven shaft. In a preferred embodiment the driving gear includes a lubricant reservoir and a lubricant passage communicating to the end face of the support boss in contact with the floor of the groove. The sidewalls of the groove constrain the support boss against longitudinal movement with respect to the axis of the driven shaft.