July 06 2014 0Comment
eot single girder crane

What is a Bridge in EOT Crane

A Bridge EOT Crane also called Overhead Crane, Industrial Crane, or Overhead Travelling Crane is a load handling machine that lowers, lifts and transports a loading material vertically and horizontally. Typically, this kind of Crane includes a hook-and-line mechanism that moves along a horizontal beam which further moves on a runaway beam, the supporting structure. The Crane is mounted on two overhead tracks or rails with the major structural component of the Crane forming a bridge helping it move with the length of the rails.

Overhead Bridge Crane is operated by an operator, either with a wired pendant station or wireless controls. If you see its typical side, the Crane is utilized for the multi-directional movement of loading materials to help storing, fabricating, and loading or unloading works outside in a yard, inside a facility, or at a shipping port or a railway station depo, and other application environments.

To understand this type of crane, you should know about is components first-

Bridge Crane components

In general, the Bridge Crane consists of three major parts, the crane bridge, the hoist or trolley, and the runway.

  1. Bridge – The Bridge is made as a single or double, box or beam girder that traverses down the runway. The advantages of each configuration are mentioned below.
  2. Hoist and Trolley– The hoist is the component in the Crane that lifts your loading material up and down while it traverses crossways across the bridge.
  3. Runway– Constructed either tied to the building structure or freestanding, the runway maps out the area your Crane can put service to. This is an imperative component with engineering considerations.

Bridge Crane Configuration

Bridge EOT Crane has two configurations- Top running Bridge Cranes and Under running Bridge Cranes.

  1. Top running cranes: Top Running crane refers to the Crane that consists of the bridge travel on the top of rails placed on a runway beam supported by either column specially made for the Crane or the building columns. Also called bridge crane is the commonest crane configuration with the property that the machine loads are transmitted to the freestanding structure or supporting columns and with the benefit of minimal headroom and maximal height of lift.
    • Classification of top running bridge cranes

Top running bridge cranes can be again classified into Single, Double, and Box Girder Bridge Crane in terms of girder types.

      1. Single Girder Crane: This consists of a trolley hoist unit, two end trucks, and a single bridge girder, on the bottom flange of which the trolley runs on. These cranes are manufactured for your work can be cost-effective or cost-friendly. The machine has lower wheel loads, and as such, it saves new support structures and then you can add more lifting capabilities to your runway structure without doing any up-gradation.
      2. Double Girder Crane: This consists of a trolley hoist unit, two end trucks, two bridge girders, on the top of which placed the rails on which the trolley runs. Double Girder Crane gives better hook height for the hoist of the Crane placed or fixed on top of the bridge rather than at the bottom.
      3. Box Girder Crane: Box girder crane is designed with a girder formed by several two walls, top and bottom plates with stiffeners which are in the shape of an enclosed rectangular tube instead of an I-beam or H-beam. The Crane is employed for handling heavy-duty material with the feature of enormously stringency and durability.
  1. Under running cranes: Under-running crane also called, or under-hung crane or Underslung Crane includes the end trucks ride on the bottom flange of the runway, and it is generally suspended from the roof as there is no requirement for extra columns for the support of the runway. An under-running crane has the benefit of taking no floor space and thus helps save cost for supporting system. Additionally, an under-running can be used at the sloped ceilings or many crane systems.
    • Classification of under-running or under-hang crane

As per crane girder terminology, under-hang or underslung or the under-running can also be put into the group of a single girder, double girder and box girder cranes.

      1. Single girder under running Bridge crane provides you with a cost-effective material handling solution for it can save new support structure because of its reduced wheel loads, which also makes it possible to add more lifting capabilities without up-gradation. Single girder under running crane gives you a reasonable load handling solution as it can save new support structure due to its abridged wheel loads, making it possible to include more lifting capabilities without upgrading it.
      2. Double girder under running Bridge crane generally lifts loads over 25 tons, which is generally given with a complete material handling solution. It offers a higher lifting height for the crane hook that travels between the beams when compared with a Single Girder Crane.

Key factors in EOT Bridge Crane.

  1. Design of Bridge– The Bridge included in an EOT Crane can be the underslung or top running. A top riding bridge can take heavier loads, but an underslung bridge is handier when it comes to transfer loads and interface with monorail systems.
  2. Load Capacity- The Bridge has to be labelled on both sides with the maximal load capacity and, if an overload device is installed, a load test is a must.
  3. Bumpers and Stops– Based on the general operating speed of a bridge crane, stops or bumpers may be required to prevent over travel. These bumpers sop up energy and mitigate the shock of a travelling bridge. Stops make the crane stop completely without causing jerks.

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