Blocks

Crown Blocks

WCI designs and manufactures a complete line of standard and custom crown blocks for masts and derricks in accordance with API Specification 8C.

Mast-type crown blocks are designed in either a standard or skewed-type configuration. Either type can accommodate air hoist sheaves, core line sheaves and other attachments as specified by the customer.

Skewed-Type Crown Blocks

The skewed-type crown block was developed and patented by Lee C. Moore Corporation. With this type of crown block, the flat side of the traveling block is presented to the racking platform, allowing the derrick man to reach the elevators with greater ease.

In the design of the skewed-type crown block, the fast line sheave is positioned independent of the sheave cluster which optimizes the drum fleet angle, ensures proper spooling of the line on the drawworks drum and minimizes line wear.

Derrick crown blocks are also designed and built with additional sheaves to position the deadline or fastline inside or outside the derrick to avoid drill line interference with special derrick accessories, such as automatic pipe handling systems, power swivels and motion compensators.

Typical Derrick Crown Block Sizes and Specifications

Capacity (tons)	Rated Static Hook Load Capacity (tons)	Number of Sheaves	Sheave Diameter	Groove Diameter
420	350	6	42"	1-1/4", 1-3/8"
483	500	7	50"	1-3/8", 1-1/2"
583	500	7	60"	1-3/8", 1-1/2"
743	650	8	60"	1-1/2", 1-5/8"
857	750	8	60"	1-1/2", 1-5/8"
1,125	1,000	9	72"	1-7/8", 2"

WCI Crown Block and Traveling Block Construction Features

WCI designs and manufactures a full line of standard and custom traveling blocks in accordance with API Specification 8C.

As a pioneer in the petroleum equipment industry, WCI has consistently been a leader in the development of high capacity and special application traveling blocks to meet the demanding needs of its customers.

Traveling blocks designed and built by WCI have a minimum height and width dimension to allow maximum travel and working space for handling any load requirement.

Standard traveling blocks are available with capacities up to 1,000 tons. Custom built traveling blocks can also be designed to meet customer needs.

Sheaves incorporated into crown and traveling blocks are fabricated from rolled steel plate and forged steel hubs. This method of manufacturing eliminates the imperfections often found in steel casting. Sheave grooves are formed for each specific wire line size and flame hardened to resist wear. Sheaves are mounted on tapered roller bearings. Bearings are individually lubricated through grease fitting conveniently located on the end of the shaft. Shafts are also heat treated to develop required strength.

Typical Traveling Block Sizes and Specifications

Capacity (tons)	Numbers of Sheaves	Sheave O.D.	Groove O.D.	Weight lbs. (est.)
350	5	42"	1-1/4", 1-1/3"	8,800
500	6	50"	1-3/8", 1-1/2"	13,500
500	6	60"	1-3/8", 1-1/2"	17,500
650	6	60"	1-1/2", 1-5/8"	22,000
750	7	60"	1-1/2", 1-5/8"	25,500
1,000	8	72"	1-7/8", 2"	30,600