Lifting lugs are small projections attached to, or built into, heavy components. A lifting lug or a padeye, is essentially a plate with a hole in it where the hole is sized to fit a clevis pin. Industry codes of practice caution against attempts to lift or move mechanical equipments by wrapping chains or cables around the equipment. Instead, the proper procedure is to thread cables or hooks into the lifting lugs, and to use a crane or similar power source to provide the upward thrust. Loads are transferred to one mechanical component to another using lifting lugs combined with the clevis pins.
Applications where lugs are used include:
strongbacks with padeyes, lifted with shackles and other rigging
connections between actuators and other structure (i.e. trunnion joint, clevis joint)
door hinges
Lifting lugs must be designed in a such a way that, it can able to carry complete weight of the mechanical equipment while lifting and to withstand various kinds of forces acting on it while transportation and installation.
Typical Lifting Arrangements for Vessel:
Different types of Lifting Arrangements:
Typical Lifting Arrangements for Horizontal Vessels:
Typical Lifting Arrangements for Leg Supported Vessels:
Horizontal to vertical lifting Forces:
Horizontal to vertical lifting Forces Calculations:
Horizontal to vertical lifting Forces Calculations:
Sample Problem:
Lifting Lug Design
Thickness calculations:
PV Elite Forces and sign Conventions:
For vertical lift:
For Horizontal Lift:
PV Elite Forces and sign Conventions
PV Elite Lifting Lug Sample Example:
Reference: whatispiping.com
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