Mechanical Advantage Progression

Written By: Lance Piatt

Thank you to Peak Rescue Institute for the graphics

In this section, students will learn five different MA systems: 1:1, 2:1, 3:1, 4:1, and 5:1. This range of MA systems is sufficient to address the majority of rescue hauls encountered in normal field operations. As with most other aspects of rope rescue, consistent practice building and operating MA systems will ensure that the rescuer is prepared to apply these concepts and skills in an emergency.

Figure 9-1 illustrates the 1:1 and 2:1 MA systems. A 1:1 haul system is included here primarily to help demonstrate the theory and progression of MA systems. A 1:1 haul system provides essentially no mechanical advantage. Since the change of direction pulley is attached to the anchor it generates force on the anchor rather than the load. Removing the pulley and applying the same force to haul the rope directly uphill will result in roughly the same force to the load.

There are practical applications for the 1:1 system pictured. Adding a progress capture device will render the system self-tending, meaning the rope can be released and the load will maintain its position.

The 2:1 is the simplest of the MA systems presented here. The haul pulley may be attached directly to the load or it may be attached with a prusik at any point on a separate rope supporting the load. Notice the haul pulley in the 2:1 system splits the load between the anchor and the haul team.

To illustrate, if the load weighs 100 pounds, the anchor will support 50 pounds and the haul team will support the other 50 pounds. Slightly more than 50 pounds of input from the haul team will raise the load.

The next illustration (Fig. 9-2) shows 3:1 and 5:1 MA systems. This 3:1 MA system, commonly known as a Z-rig, is one of the most frequently used haul systems in rope rescue. The 3:1 is a progression of the 1:1 discussed previously; the increased MA results from routing the haul end of the rope from the change of direction pulley through an additional haul pulley attached with a prusik back to the load side of the rope.

The 5:1 MA in the same illustration is a progression of the 3:1 and is built with one additional haul pulley attached with a prusik. This system incorporates haul pulleys moving toward one another, which is one of the reasons it is considered a complex MA system.

Resetting the complex 5:1 will require moving the haul pulleys away from one another, one toward the anchor and one toward the load. Also, this system requires that haulers pull away from the anchor and toward the load, which may or may not be an advantage depending on the application.

Figure 9-3 shows an alternate 5:1 MA system. The simple 5:1 requires an additional change of direction pulley, and both haul pulleys move in the same direction at the same speed, which simplifies resetting the system. In addition, the haulers will pull away from the load and toward the anchor with this system, which again may or may not be an advantage depending on the application.

The final haul system taught in the Technician Course is a 4:1 simple MA, commonly known as a block and tackle or a set of fours. This system is generally built and left pre-rigged using purpose-made tandem pulleys at both ends. At least one of the tandem pulleys will have a Becket attachment used to fasten the bitter end of the rope.

Depending on its orientation, the simple 4:1 can actually be either 4:1 or 5:1.

If the block and tackle pictured below were flipped end for the end it would be a 5:1 MA (Fig. 9-4).

Peace your Days

Lance

Categories
Facebook
Twitter
LinkedIn
Email

About The Author:

Related Posts

295 thoughts on “Mechanical Advantage Progression”

  1. Nice post. I learn something totally new and challenging on sites I stumbleupon everyday. It will always be helpful to read articles from other writers and use something from other sites.

  2. י עמית הר-שלג, במאי ומפיק מוזיקלי בעל ניסיון רב בתחום
    הבידור. י אלירן נונה, אמן בעל ניסיון רב
    בתחום הקעקועים והפירסינג. החל את קריירת הקעקועים והפירסינג בשנת 2006 במרכז שם למד, התמחה
    והתמקצע. אילן כנר, הממציא והיזם, שם
    לעצמו מטרה ליצור סביבה אסתטית
    ובמחיר שווה לכל נפש. בשנת 2010 עבר לארצות
    הברית שם התארח ועבד בשניים מהמכונים המתקדמים והמובילים בטקסס.
    אנו עובדים אך ורק עם החומרים המתקדמים ביותר
    בענף. אנו מציעים לכם ניסיון וותק של למעלה מ- 30 שנה בשילוב עם מכשור טכנולוגי מתקדם המאפשר בחינה יסודית יותר של מיקום
    הנזילה מבלי לגרום לנזק לקירות
    הבית! כדי לא ללכת לאיבוד, לפני הכול בררו על סוגי העיסוי הנפוצים
    והחליטו איזה עיסוי מתאים לכם במיוחד:
    עיסוי רפואי, עיסוי שבדי, עיסוי עם אבנים חמות או בכלל עיסוי עד הבית?
    עיסוי נדיר ומיוחד בתל אביב.
    כל הפינוקים לנופש מושלם- בריכת שחייה, ספא פרטי, אבזור הסוויטה מושלם והעיצוב ייחודי, חדשני ומיוחד מאוד לזוגות
    רומנטיים בלבד. אני מאמינה כי כל חוויה שאנו חווים,
    נחקקת בגוף בשתי רמות – הפיזית והנפשית וכל
    חוויה משפיעה על תפקודנו. כאשר אתם
    באים לבחור חשפניות, זכרו כי אסור לכם להתפשר.
    העיסויים מפנקים בנתניה/השרון הפכו
    לאטרקציה המרכזית בימי הפינוק השונים, אך כדאי
    לזכור כי מטרת העל של העיסוי מפנק היא לייצר שלווה ורוגע.

  3. you’re in reality a just right webmaster. The web site loading velocity is incredible. It sort of feels that you’re doing any distinctive trick. In addition, The contents are masterpiece. you’ve performed a great process on this topic!

  4. I cannot thank you more than enough for the blogposts on your website. I know you set a lot of time and energy into these and truly hope you know how deeply I appreciate it. I hope I’ll do a similar thing person sooner or later.

  5. Spot on with this write-up, I truly believe this website requirements a lot much more consideration. I’ll probably be once more to read much much more, thanks for that info.

  6. fantastic post, very informative. I wonder why more of the ther experts in the field do not break it down like this. You should continue your writing. I am confident, you have a great readers’ base already!

  7. I think it is a nice point of view. I most often meet people who rather say what they suppose others want to hear. Good and well written! I will come back to your site for sure!

  8. I like the helpful information you provide in your articles. I’ll bookmark your blog and check again here frequently. I am quite certain I’ll learn many new stuff right here! Best of luck for the next!

  9. Hello there I am so delighted I found your weblog, I really found you by mistake, while I was searching on Google for something else, Anyhow I am here now and would just like to say cheers for a remarkable post and a all round exciting blog (I also love the theme/design), I don’t have time to browse it all at the moment but I have book-marked it and also included your RSS feeds, so when I have time I will be back to read a lot more, Please do keep up the superb work.

  10. of course like your web-site however you have to check the spelling on several of your posts. Many of them are rife with spelling problems and I find it very troublesome to tell the reality then again I will surely come back again.

  11. Its like you read my mind! You seem to know a lot about this, like you wrote the book in it or something. I think that you can do with some pics to drive the message home a bit, but other than that, this is wonderful blog. A great read. I’ll certainly be back.

  12. Mo Qingfeng thought about does cialis cure erectile dysfunction Shop Vitamins And Supplements the ordinary people in those stories who need to spend money to buy things, and now trimix cure my erectile dysfunction they I does cialis cure erectile dysfunction became a great practitioner, but I also need to spend money to buy does cialis cure erectile dysfunction things, so does cialis cure erectile dysfunction I nodded priligy where to buy If you take medications for seizures

  13. I have been curious about these trends, and you have really helped me. I have just told a few of my friends about this on FaceBook and they love your content just as much as I do.

  14. I’m so happy to read this. This is the type of manual that needs to be given and not the random misinformation that’s at the other blogs. Appreciate your sharing this best doc.

  15. I have to say this post was certainly informative and contains useful content for enthusiastic visitors. I will definitely bookmark this website for future reference and further viewing. cheers a bunch for sharing this with us!

  16. Hello, I think your blog might be having browser compatibility issues. When I look at your website in Chrome, it looks fine but when opening in Internet Explorer, it has some overlapping. I just wanted to give you a quick heads up! Other than that, awesome blog!

  17. I don’t know if it’s just me or if everybody else experiencing issues with your site. It appears as though some of the written text on your content are running off the screen. Can someone else please provide feedback and let me know if this is happening to them as well? This could be a problem with my web browser because I’ve had this happen before. Appreciate it

  18. It’s the best time to make some plans for the future and it is time to be happy. I’ve read this post and if I could I wish to suggest you some interesting things or tips. Maybe you can write next articles referring to this article. I wish to read even more things about it!

  19. clomid bodybuilding Outcomes Mean number of oocytes retrieved, cycle cancellation rate, total administered gonadotropins dose; length of ovarian stimulation, clinical ultrasound confirmed pregnancy rate per started cycle, miscarriage rate, ongoing pregnancy rate at 12 weeks gestational age Other outcomes reported in study but not entered into review fertilisation rate, implantation rate, pregnancy rate per oocyte pick up and per embryo transfer Notes Risk of bias Bias Authors judgement Support for judgement Random sequence generation selection bias Low risk Randomization was performed using a computerized algorithm without any restriction.

  20. I’m partial to blogs and i actually respect your content. The article has actually peaks my interest. I am going to bookmark your site and preserve checking for new information.

  21. We absolutely love your blog and find the majority of your post’s to be exactly what I’m looking for. Do you offer guest writers to write content to suit your needs? I wouldn’t mind composing a post or elaborating on a number of the subjects you write about here. Again, awesome weblog!

  22. However, it is virtually all done with tongues rooted solidly in cheeks, and everyone has absolutely nothing but absolutely love for his or her friendly neighborhood scapegoat. The truth is, he is not just a pushover. He is basically that special variety of person strong enough to take all of that good natured ribbing for exactly what it is.

  23. of course like your web-site however you have to check the spelling on several of your posts. Many of them are rife with spelling problems and I find it very troublesome to tell the reality then again I will surely come back again.

  24. Hey very cool site!! Man .. Beautiful .. Amazing .. I will bookmark your website and take the feeds also…I’m happy to find so many useful information here in the post, we need develop more strategies in this regard, thanks for sharing. . . . . .

  25. I just couldn’t leave your web site prior to suggesting that I really enjoyed the standard info an individual supply to your guests? Is going to be again continuously in order to inspect new posts

  26. I dont think Ive caught all the angles of this subject the way youve pointed them out. Youre a true star, a rock star man. Youve got so much to say and know so much about the subject that I think you should just teach a class about it

  27. Great post. I was checking constantly this blog and I’m impressed! Very useful info specifically the last part 🙂 I care for such info much. I was looking for this certain information for a very long time. Thank you and good luck.

  28. This blog post is excellent, probably because of how well the subject was developed. I like some of the comments too though I could prefer we all stay on the subject in order add value to the subject!

  29. Simply want to say your article is as amazing. The clarity in your post is just great and i can assume you’re an expert on this subject. Fine with your permission allow me to grab your feed to keep up to date with forthcoming post. Thanks a million and please keep up the gratifying work.

  30. Good day! This is my first comment here so I just wanted to give a quick shout out and say I really enjoy reading through your articles. Can you recommend any other blogs/websites/forums that cover the same subjects? Thanks a lot!

  31. Great blog here! Additionally your website rather a lot up very fast! What host are you the usage of? Can I get your associate link for your host? I desire my website loaded up as fast as yours lol

  32. Easily, the post is really the greatest on this laudable topic. I concur with your conclusions and will thirstily look forward to your future updates. Saying thank will not just be sufficient, for the wonderful c lucidity in your writing. I will instantly grab your rss feed to stay privy of any updates. Solid work and much success in your business enterprise!

  33. I’m impressed, I need to say. Really rarely do I encounter a blog that’s both educational and entertaining, and let me tell you, you have hit the nail on the head.

  34. Great site you’ve got here.. It’s hard to find high-quality writing like yours nowadays. I really appreciate people like you! Take care!!

  35. Hi my family member! I want to say that this article is amazing, great written and include approximately all important infos. I’d like to see more posts like this .

  36. Spot on with this write-up, I actually believe that this amazing site needs a great deal more attention. I’ll probably be returning to see more, thanks for the information!

  37. Greetings! Very useful advice in this particular post! It’s the little changes that will make the largest changes. Many thanks for sharing!

Comments are closed.