Lovejoy DD4B Double Universal Joint 3/8 in Square and 3/8 in Round

68514476407, DD Type – Special Bores

Dimensional Data

Performance Data

Lovejoy DD4B Double Universal Joint 3/8 in Square and 3/8 in Round

This Lovejoy DD4B carbon steel double pin-and-block universal joint with a 3/8″ square bore and a 3/8″ round bore and keyway is designed to connect two rotating shafts at angles up to 25 degrees. This universal joint compensates for both parallel and angular misalignments, and its double joint configuration provides two points of flexion to help minimize speed fluctuations and torsional vibration during operation.

The hubs, center block, and pins are made of American Iron and Steel Institute (AISI) 1144 carbon steel for strength and durability, and the bored hubs fit onto shafts without the need for machining. A set screw on one end secures the joint into position on the shaft. Operating temperatures range from -20 to 212 degrees F. For optimal wear and extended life, boots (sold separately) are recommended, and boot retaining grooves are standard on this design.

It has a .75″ outside diameter and is 5.38″ in length. This universal joint provides a uniform speed ratio between driving and driven shafts, and is suitable for applications requiring moderate torque transmission, such as compressors, fans, machine tools, printing presses, and textile machinery. Universal joints (also called U-joints, universal couplings, Cardan joints, Hooke’s joints, or Hardy-Spicer joints) are used to transmit motion and rotational power, or torque, between two shafts that are offset at an angle.

Most universal joints consist of two yokes and a middle assembly; the hub end of each yoke attaches to a shaft while the yoke ears attach to and pivot around the middle assembly to accommodate shaft misalignment. The type of middle assembly determines its usage—pin and block joints are suitable for transmitting high torque, needle bearing joints are used to handle high rotational speeds, and ball and socket joints are used in applications requiring low backlash (play between moving parts).

The body of the universal joint may include a single joint to accommodate only angular misalignments between shafts, or two joints to accommodate both angular and parallel misalignments. Available in a variety of materials and configurations, universal joints are used in applications including motor vehicles, conveyors, medical and optical devices, forestry and mining equipment, robotics and space exploration, and aeronautics, among others.

Lovejoy manufactures flexible couplings, universal joints, variable speed drives, and other transmission and mechanical power products. The company, founded in 1900, is headquartered in Downers Grove, IL.