Yoke Blocks
A rigging block redirects wire rope or chain in a block-and-tackle or crane rigging system, and in a snatch block application, allows rope to be reeved through the block without threading from the rope end. Yoke manufactures rigging blocks in forged alloy steel, snatch blocks, hook blocks, and sheave blocks, for wire rope and chain rigging applications.
About Yoke Blocks
Holloway Houston stocks the Yoke block line for rigging, offshore, and marine applications. WLL ratings and rope or chain size compatibility are marked on each block per manufacturer documentation.
A rigging block is a pulley assembly, a sheave in a housing with an attachment point above. In a block-and-tackle system, multiple blocks multiply the pulling force of the rigging line. In crane rigging, a snatch block redirects the pull of a wire rope winch line to reach a load that isn't in line with the winch.
Yoke blocks are forged alloy steel with machined sheaves sized to match the wire rope or chain diameter they are designed to work with. The sheave profile matters, a sheave too small for the rope diameter concentrates the bending stress at the sheave, reducing rope fatigue life. Yoke block and sheave specifications are matched per their product documentation.
ASME B30.26 (Rigging Hardware) addresses blocks as rigging hardware components in load-handling service, covering design requirements and inspection criteria.
Types of Yoke Blocks
Snatch Blocks
Snatch blocks have a side-opening housing that allows wire rope to be loaded into the sheave groove without threading from the rope end. This makes them the practical choice for change-of-direction applications in rigging setups where threading from the end isn't an option. A snatch block opens on the side, the rope is dropped in, and the housing closes with a pin or latch. WLL ratings apply to the combined load on the block, the anchor load, not just the line tension.
Hook Blocks
Hook blocks mount a crane hook below the sheave housing, making them the standard connection at the end of a crane hoist line. The hook block hangs from the crane's wire rope reeve, and the load attaches to the hook below. Yoke hook blocks are sized to match the crane hoist rope diameter and carry WLL ratings for the hook below.
Swivel Eye Blocks
Swivel eye blocks have a rotating eye attachment at the top instead of a fixed bail or shackle. The swivel allows the block to orient with the rope pull direction without putting a twist on the attachment above. Used in block-and-tackle systems and rigging setups where the block angle changes during the pull.
Pulley Blocks (Multi-Sheave)
Multi-sheave pulley blocks are used in mechanical advantage rigging systems, block-and-tackle setups where multiple reeved lines multiply the pull force. Yoke multi-sheave blocks are available in single, double, and triple sheave configurations for wire rope rigging systems.
Yoke Block Sizes and Rope Compatibility
Block types:
- Snatch.
- Hook.
- Swivel eye.
- Multi-sheave.
Wire rope diameters:
- Per Yoke product data for each block model.
WLL range:
- Marked on each block body per manufacturer documentation.
Material:
- Forged alloy steel housing.
- Machined sheaves.
Marking:
- WLL.
- Rope/chain diameter.
- Manufacturer ID per ASME B30.26.
Yoke snatch blocks cover capacity ranges from 2 tons through 20 tons across three product lines: Light (2-8T), Forged (12-15T), and Super (20T). Specific WLL depends on block size, sheave diameter, and wire rope size call Holloway Houston at 1-888-496-4700 for stock availability and exact ratings per model.
Why Yoke for Blocks
Yoke's forged alloy body means the block housing maintains its geometry under the combined loads of block-and-tackle rigging, the anchor load on a change-of-direction snatch block can be substantially higher than the line tension alone. ISO 9001 certification and proof testing give maintenance managers and rigging supervisors the documentation to back up the WLL rating.
The snatch block line covers the most common application need, rope diameters from light rigging through heavy crane line, without specialty ordering lead times.
Holloway Houston provides rigging inspection services covering blocks and hardware per applicable ASME standards.
Shop by Product Type
Yoke Block Applications by Industry
- Jobsite rigging : Snatch blocks on jobsite cranes and winch rigging to redirect pull angles for difficult-access loads.
- Marine and Offshore : Block-and-tackle rigging on vessels and platforms where snatch blocks redirect wire rope winch pulls.
- Oil and Gas : Rigging blocks on turnaround work where winch rigging and chain hoists pull equipment through confined or angled access.
- Mining : Change-of-direction blocks in shaft sinking and underground rigging setups.
- Forestry and Logging : Snatch blocks on cable yarding and log-hauling rigging systems.
Why Holloway Houston for Yoke Blocks
Holloway Houston stocks Yoke blocks alongside wire rope, shackles, and rigging hardware from Houston. Over 65 years in the rigging business means our team can help match a block to the rope diameter, rigging setup, and WLL requirement without a catalog guessing game.
Related Rigging Hardware
- Yoke Shackles : Anchor shackles connect snatch blocks to structural attachment points and rigging pickup points.
- Yoke Swivels : Add swivel capability above block attachments to prevent rope twist in block-and-tackle systems.
- Yoke Hooks : Crane hook and shank hook hardware for connecting block assemblies to loads and crane hoists.
Block Safety and Awareness
Rigging blocks fall under ASME B30.26 (Rigging Hardware) for design, marking, and inspection in load-handling service. OSHA 1926.251 applies to rigging equipment used in construction. Crane blocks and hoist equipment are also covered by OSHA 1910.179.
- The WLL on a snatch block is the anchor load, the load on the block's attachment point, not the tension in the line through the sheave. In a change-of-direction reeving, the anchor load can approach twice the line tension depending on the fleet angle.
- Sheave-to-rope diameter ratio affects wire rope fatigue life. Yoke block documentation specifies the rope diameters each block's sheave is designed for.
- Pre-use inspection of blocks covers the sheave for wear, the housing for cracks or deformation, and the attachment bail or pin for wear and free movement.
- Blocks with seized sheaves, sheaves that don't rotate freely under the rope, generate additional friction loads and rope wear.
- Side-loading on block attachment bails is not covered by the standard WLL. Block bails are rated for in-line loading unless the manufacturer documentation specifies a side-load rating.
Frequently Asked Questions
A snatch block redirects the pull of a wire rope or cable to a different angle. The side-opening design allows the rope to be dropped into the sheave groove without threading from the rope end. Common uses include changing the direction of a winch line, increasing mechanical advantage in a rigging system, and reaching loads that aren't in direct line with the winch or hoist. The WLL on a snatch block is the anchor load on the block, not the tension in the rope.
Yoke snatch blocks use a side-opening hinged housing that swings open to accept the rope. A pin or latch closes and secures the housing once the rope is loaded into the sheave groove. The closure is checked before loading to confirm the housing is fully secured.
Rope compatibility for Yoke blocks is listed per model in the Yoke product data. The sheave diameter and groove profile are matched to specific rope diameter ranges. Using a block with a sheave too small for the rope diameter concentrates bending stress and accelerates rope fatigue.
A snatch block is a rope-redirecting pulley with a side-opening housing and an attachment point above for mounting to a structure or shackle. A hook block hangs from the crane hoist line and has a hook below for load attachment, it is the bottom block of the crane's reeving system. Hook blocks are a hoist component; snatch blocks are a rigging component.
ASME B30.26 (Rigging Hardware) covers rigging blocks in load-handling service. OSHA 1926.251 applies to rigging equipment used in construction. Crane hoist blocks and overhead crane equipment are covered by OSHA 1910.179.
DISCLAIMER
Rigging blocks are load-bearing components. Selection, rigging, and inspection call for training consistent with ASME B30.26, applicable crane and rigging standards, and manufacturer documentation. The information on this page is provided for general product awareness and does not replace qualified engineering judgment or site-specific rigging procedures.