System Efficiency Effect of pulley friction. Most rescue pulleys have an efficiency rating of .75 to .90 (only 75% to 90% of tension is transferred from one side of the pulley to another due to friction). A carabiner used as a pulley has an efficiency of only about 50% or less (more for a steel …
System Efficiency of Mechanical Advantage Systems Read More »
Excerpt from Rigging Lab Academy’s Force Multipliers Video is at the bottom I want to look at how we add vectors together. Previously, we discussed that if someone describes a displacement where they had two miles north and one mile east, we can add those together to get that endpoint. I want to look at …
Full Video is at the bottom A force multiplier is any factor or condition that contributes to the overall stress of a rope system during a dynamic state. Rating this dynamic state or rope movement/stress is best represented as the Dynamic System Safety Factor (DSSF). In other words, what’s our weakest link during the operation …
Thanks to Peak Rescue Institute Full Video at the bottom! In general, the Ideal Mechanical Advantage (IMA) is the ratio between the distance the load moves and distances the haul team moves. In a 2:1 system the load will move 1′ to every 2′ of haul. However, this does not mean that lifting the load is twice …
Technical Articles | Anchors Part 1 This will be the first of a two-part series on anchors. This section, purposely, will not include situations that necessitate vehicles, pickets or other such portable anchors. Nor is the series meant to be an exhaustive source of information… there are numerous books on this subject. If you have …
A mechanical advantage haul system reduces the effort required to raise a load. The mechanical advantage obtained is based on the pulley effect. 1. The pulley effect If we consider a load suspended on a rope, the rope passing through a pulley above the user, with the user’s hand holding the rope on …
How to calculate mechanical advantage within a progression! Read More »
©Petzl Technical Information ©Petzl How to calculate mechanical advantage A mechanical advantage haul system reduces the effort required to raise a load. The mechanical advantage obtained is based on the pulley effect. 1. The pulley effect If we consider a load suspended on a rope, the rope passing through a pulley above the user, with …
Ascenders and Clamps Technical Tips: How to calculate mechanical advantage Read More »
A mechanical advantage haul system reduces the effort required to raise a load. The mechanical advantage obtained is based on the pulley effect. 1. The Pulley Effect If we consider a load suspended on a rope, the rope passing through a pulley above the user, with the user’s hand holding the rope on the …
How To Calculate Mechanical Advantage with Petzl Gear Read More »
What if trees had ratings? What an amazing concept. John Morton, an engineer-scientist-visionary-technician, has been doing canopy studies for years and knows how they are affected by wind. Trees, whether alone or in community, are all influenced by wind and all have a certain “wind rating” to them. When SAR members show up on scene, and …
From John Morton for ITRS: Tree Anchor “Ratings” Based on Wind Loading Read More »
The ante has been raised in our industry. The need for running teams and systems in a more streamlined manner has become less a wish and more a practical goal. Some have met this challenge and surpassed it, while others are still pursuing the vision. There are real-life obstacles we face (every day) that stand …
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