Block and Tackle Suspension System
in Devault, PA
Block & Tackle “101″
(Skip this if You Know Your Block & Tackle Basics.)
The concept was first thought to have been devised by Archimedes on the Island of Syracuse sometime around 237 B.C.E. This is basic physics: you pass a rope through pulleys and gain a percentage mechanical advantage for lifting or pulling horizontally with each drop of rope. The higher you go up with your mechanical advantage the more rope you must move to attain your goal. To ascend yourself 25 feet up without using any mechanical advantage just requires you to pull 25 feet of rope but it would be very difficult to pull. Using a four-to-one mechanical advantage, you would need to pull 100 feet of hope but it would be very easy to pull. This is the physics principle behind why our system is so easy to use.
The System *99* is such a success because it utilizes this physics principle to ascend and descend personnel in a safe and user-friendly way. Surrounding the basic block & tackle suspension system from Devault, PA, International Safety Equipment has patented this use of this principle within the System *99* that allows simple, intuitive and multiple usages.
Definitions of block & tackle components
BLOCK = Top Head or Pulley
TACKLE = Pulleys that are Mounted under the Top Head Block or Pulley & the Lower / Traveler Pulleys & Normally the Rope or Line is also referred to asa Part of the Tackle
BIGHT = The Termination / End Point / at the Load Side of the System
LOAD SIDE ROPES = the Ropes that Suspend the Load
FREE SIDE ROPE = The Rope you Pull on to Move your Load, and Allow to Slip through Your Handle & Fingers to Control Descent
HANDY BILLY = Another Name, (In Nautical Speak), for a Small Portable Block~n~Tackle
PURCHASE = Another Name for the Tackle
FALL = The Free-Side Rope
BECKET = Either the *Bight* Tie-off Point Under the Top Head Assembly (or) the Lower Karabiner Mounting Hole in the bottom the bottom traveler pulley or any pulley attachment point
OFFSET BECKET = Opposite Side of Pulley Mounting Point from Above Captioned Becket
Facts about the System *99*
- The System *99* is the most versatile rescue and utility work system available today. It utilizes the lifting system of mechanical advantage combined with its patented “constant high percentage friction lowering brake”. This is the latest evolution of the block and tackle suspension system.
- This lightweight, compact, universal system can be set up in a few seconds and can perform a wide variety of functions.
- One person can operate this system, raise and lower him/herself without the Help of a co-worker. Should an emergency situation occur, a top-side observer can utilize the System *99* to rescue an incapacitated co-worker. Additionally, the System *99* can be used to raise and lower tools and equipment.
- The core of the System *99* personnel raising and lowering system is called the “Head Unit” (pictured below). It utilizes a stationary block in which the main pulley is mounted on a 4.75″ by 8.5″ by 3/8″ thick aircraft aluminum backing plate. The head unit weighs 3.5 pounds and provides 360-degree portability. It is so flexible it allows the user to move at any angle and in any direction.
- The large pulley on the head unit on the System *99* is a friction brake head block assembly that consists of a 3.5″ diameter by 2″ deep aircraft aluminum capstan roller drum. It is mounted on a 4.75″ by 8.5″ by 3/8″ thick aircraft aluminum backing plate with an offset bend so it hangs straight under load. Mounted inside the drum is an anti-reverse spinlock, also known as a Sprague Clutch. The rope containment area of the drum is 3/8″ thick. In this bolt together pulleys lifting system, the rope, capstan, and drum all ride on a 3/4” steel carrying bolt, which is supported on sealed ball bearings.
- The System *99* utilizes our special ‘ISE’ Series 3000 rope. It is 3/8” (9.5mm) diameter Kernmantle, (core sheathed) rope, which is wrapped 2.5 times around the roller drum. This creates 900 degrees of the surface contact area. This special rope has a breaking strength of 6,000 Pounds! It is decay and rot resistant and can withstand temperatures in excess of 400 degrees.
- The Three ‘Teflon’ ® coated rope guides located around the drum keep the rope from tangling or overlapping and tracking properly.
- All the aircraft aluminum components are coated with a “MIL-SPEC” coating to resist corrosion.
- When using the International Safety lifting-lowering system to lower a person or object, the roller drum automatically locks (courtesy of our “Constant High Percentage Friction Lowering Brake”). The 2.5 turns of rope around it provide a 90% to **95% Friction Braking Action. 10 to 20 Pounds of force on the free side of the rope is all that is required to hold a 200-pound load stationary. This essentially means the user is in total control of the rate of decent at all times.
- Another optional configuration for the System *99* personnel raising and lowering system is to wrap the rope only 1.5 times around the Drum, (540 Degrees of Surface Contact Area versus 900 with 2.5 times of rope wrap). This provides a 55% to 60% friction braking action. This option is intended for expert users who want the option of a faster descent. Keep in mind that these braking percentages are estimates and are based on new, clean, and dry ropes.
- For the “tackle” portion of a system, we add roller pulleys to the load side under the backing plate. This completes the suspension system and provides an adjustable mechanical lifting advantage system.
- Although normally used vertically, this System can be used horizontally or in a compound (horizontal to vertical) application. Our “Custom Edge Roller” (stock #2299) is particularly useful for this. Give us a call anytime and we will help you customize the System *99* to fit your needs perfectly.
Where can the System *99* be used?
Job-Site Lifting-Lowering Equipment
Refineries, grain elevators, silo product recovery, silo construction, building construction and maintenance, subways, hi-rise settings, electrical work, painting work, plastering work, pest control tasks, steep-angle roofers, window washers, chairlift operators, ski areas, railroads, breweries, naval ship operations, communication towers, offshore drilling platforms, bridge-building or inspecting, dam-building or inspecting, theatrical rigging, home and hospital movement of patients.
Fire and Rescue Lifting-Lowering System
Fire departments, high-angle or low-angle rescue squads, helicopter rescue.
Treehouse Lifting-Lowering System
Treehouse owners (yes, we’ve sold these units to treehouse aficionados so they can safely and easily access their secluded getaways).
Marine Lifting-Lowering System
Yacht or sailboat mast ascent and descent, “man overboard” rescue from a boat, installing or maintaining heavy yachting equipment (such as outboard motors).
…and countless other applications.