Bypass blocks (pulley blocks)
A bypass crane block (pulley block) is an element of a system of movable and fixed blocks, bent around by one flexible body (in crane technology, this is usually a rope or cable). If the bypass block fails in the lifting equipment, then such a part cannot be repaired - according to safety requirements, it must be replaced with a new one.
When the pulley block needs replacement?
- in the presence of through cracks;
- when the groove of the block is worn over 40% of its original radius.
Bypass block D=400 mm
Bypass block D=300 мм
Bypass block D=500 mm
How to buy bypass blocks (pulley blocks) in the «El-Kran» company?
The pulley block (crane bypass block) produced by our company is stamped with a factory stamp indicating its permissible carrying capacity. Delivery times do not exceed 10 working days. Each bypass block is issued in strict accordance with GOST and has all the relevant certificates and guarantees. Our experts will competently help you to choose the most optimal combination of pulley blocks for your equipment.
Basic standardization standard: OST 24.191.05.
Drawing 22. Bypass block
- D1 - block diameter along the rope stream,
- D2 - axis diameter,
- d - rope diameter,
- R* - radius of the rope stream,
- B* - width of the rope stream,
- H* - the depth of the rope stream.
Table 22. Main overall dimensions of bypass blocks
| D1, mm | D2, mm | d, mm | R, mm | B, mm | H, mm |
|---|---|---|---|---|---|
| 200...1000 | 40...110 | 11...14 | 8 | 28 | 22 |
| 200...1000 | 40...110 | 14...18 | 10 | 34 | 28 |
| 200...1000 | 40...110 | 18...23 | 15,5 | 45 | 36 |
| 200...1000 | 40...110 | 23..28,5 | 15,5 | 55 | 45 |
| 200...1000 | 40...110 | 28,5...35 | 19,5 | 67 | 55 |
| 200...1000 | 40...110 | 35...43,5 | 24,5 | 85 | 70 |
Cargo blocks are usually an auxiliary device when lifting operations to move loads in the horizontal and inclined plane are performed. Their main purpose is to be used as a retracted device and for creating a pulley block.
The direct-acting pulley block is used for lifting mechanisms and jibs of cranes - it allows to gain more strength and reduce the tension of the flexible body. Reverse-acting pulley block is used if you need to gain speed. For example, in lift trucks in hydraulic drives of load lifting mechanisms.
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