Petzl Tandem Pulley
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Availability: NZ stock Dispatch: 5-7 working days
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Petzl Tandem Pulley - Red is backordered and will ship as soon as it is back in stock.
Description
Description
The Petzl Tandem Pulley is a double pulley specifically designed for Tyrolean traverses on ropes. Its high-quality aluminium sheaves are mounted on self-lubricating bushings, ensuring maximum efficiency. With the ability to accommodate up to three carabiners, it allows for smooth and easy manoeuvres.
Features
- The aluminium sheaves are mounted on self-lubricating bushings, enhancing overall efficiency.
- The device accommodates up to three carabiners, making it easier to use.
Specifications
| Rope compatibility: diameter | 13 mm or less |
| Sheave diameter | 21 mm |
| Ball bearings | No |
| Efficiency | 71 % |
| Maximum working load | 10 kN |
| Maximum allowable speed | 10 m/s |
| Weight | 195 g |
| Certification(s) | CE EN 12278, UKCA |
| Inner Pack Count | 1 |
Technology
Technical Notice
Declaration Of Conformity
- Download the PDF : UE-Declaration-P21-Tandem - 0.20 MB
- Download the PDF : UKCA-Declaration-P21-P21 SPE-TANDEM-TANDEM SPEED - 0.63 MB
Tips for maintaining your equipment
Inspection
PPE inspection procedure
PPE checklist
Technical Content
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.
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WARNINGS
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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 other side of the pulley; any force applied to one end of the rope is transmitted to the other end of the rope, or, in this case, to the end of the rope on the other side of the pulley.
If the load weighs 100 kg, it is clear that the user must hold 100 kg on their side to hold the load. The two rope strands each exert a pull of 100 kg, so the pulley supports 200 kg.
Note: This theory is valid for an ideal pulley of 100% efficiency, which does not exist in the real world.In reality, pulley efficiencies range from about 50 % to 98 %.To simplify calculations, this discussion is limited to ideal pulleys.
2. Calculating Mechanical Advantage in Practice
The efficiency (E) of a haul system indicates the force multiplier factor that you can exert on the rope.For example, if you are able to pull 20 kg maximum on a rope with your bare hands, a 3:1 haul system will enable you to raise a 60 kg mass.This reduction is obtained by increasing the amount of rope to be pulled: to raise a mass 1 meter with a 3:1 system, 3 m of rope must be pulled.
The efficiency (E) of a haul system may be calculated by adding the effects of each pulley.
Start by drawing a simple diagram of the system, then show the pulling force F that the hand applies to the rope.
Transmit the force F along the rope by adding the effects of each pulley.
When multiple rope strands are attached to the load (double pulley, rope clamp...), add the forces exerted by each strand.
1:1 Haul System
2:1 Haul System
3:1 Haul System
Note: The advantage of a 3:1 system is its ease of setup and that it can easily be converted to a complex system (7:1) with one additional pulley and some cord.
4:1 Haul System
5:1 Haul System
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