Skip to main content

Mechanical Flexing Couplings

The mechanical flexing couplings accept misalignment from rocking, rolling or sliding of metal surfaces. All metal mechanical flexing couplings require lubrication.

Mechanical flexing couplings are:
  • Gear coupling.
  • Grid coupling.
  • Roller chain coupling.


Gear Couplings

Gear couplings transmit the highest amount of torque and the highest amount of torque in the smallest diameter of any flexible coupling.
Each coupling consists of two hubs with crowned external gear teeth. The hubs mesh with two internally splined flanged sleeves that are bolted together. Gear couplings accommodate angular and axial misalignment by the rocking and sliding of the crowned gear teeth against the mating sleeve teeth. Parallel misalignment is accommodated by having two adjacent hub/sleeve flex points. Gear couplings require periodic lubrication depending on the application. They are sensitive to lubrication failures but if properly installed and maintained, these couplings have a service life of 3 to 5 years and in some cases, they can last for decades.

Grid Couplings

Grid couplings consist of 2 radially slotted hubs that mesh with a serpentine strip of spring steel the grid provides torsional damping and flexibility of an elastomer but the strength of steel. Grid couplings transmit torque and accommodate angular, parallel and axial misalignment from one hub to the other through the rocking and sliding of a tapered grid in the mating hub slots. The grid cross-section is generally tapered for better hub contact and easier assembly. As there is movement between contacting hub and grid metal parts, lubrication is required.


Roller Chain Coupling

Roller Chain type couplings consist of two radially sprocketed hubs that engage a strand of double pitch roller chain. Chain couplings are used for low to moderate torque and speed applications. The meshing of the sprocket teeth and chain transmits torque and the associated clearances accommodate angular, parallel and axial misalignment.

Chain couplings require periodic lubrication depending on the application. The lubrication is typically brushed onto the chain and a cover is used to help keep the lubrication on the coupling.

Comments

Post a Comment

Popular posts from this blog

Difference Between A, B & C-Class Divisions?

IMO Symbol A Class Division  IMO Symbol B Class Division  SOLAS has tables for structural fire protection requirement of bulkheads and decks. The requirements depend on the spaces in question and are different for passenger ships and cargo ships. The Administration has required a test of a prototype bulkhead or deck in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise. Types of Divisions: "A" Class "B" Class "C" Class "A" Class: "A" class divisions are those divisions formed by bulkheads and decks which comply with the following criteria: They are constructed of steel or equivalent material They are suitably stiffened They are constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test. they are insulated with approved non-combustible materials such that the average tempera

Why do we blow through engine before starting ?

The engine is blown through on air before starting it : a) To Blow out through indicator cock any residual exhaust gas or     other products of combustion trapped inside the cylinder after     shutting the engine. b) To check if any jacket cooling water from cylinder head or     turbocharger or any other source, has leaked while the engine          was shut and collected on top of piston. If while blowing                  through, water comes out of indicator cock or relief valve, we          need to investigate and rectify the fault before starting the                engine. It is imperative that the engine is blown through before        starting. There have been cases where the generator engine has        been started from control room without bothering to blow     through first, and water collected on top of piston has resulted in      a bent connecting rod and broken piston.( Reason – water can          not be compressed )

Load Line & Why it is Important

Merchant ships have a marking on their hull know as the Plimsoll line or the Plimsoll mark, which indicates the limit until which ships can be loaded with enough cargo, internationally, the Plimsoll line on a ship is officially referred to as the international load line. Every type of ship has a different level of floating and the Plimsoll line on a ship generally varies from one vessel to another.  All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line. There are two types of Load line markings:- Standard Load Line marking – This is applicable to all types of vessels. Timber Load Line Markings – This is applicable to vessels carrying timber cargo. These marks shall be punched on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background/black on a light background.  The comp