The crane is a device that is used for the lifting and moving of a load, this seems similar to that of a hoist, however it must be noted that a hoist can only lift a load vertically, where as a crane can lift a load and move it. The hoist only moves the load in one axis, while the crane can move it in two or three axises.
One of the simplest incarnations of this device is the “jib crane”. In its simplest form the jib has a cantilevered jib or boom that extends perpendicularly from a vertical mast. Depending on the design the boom has the ability to rotate, this can be achieved by the mast rotating at its base or the boom rotating at the point it contacts the mast.
This type of crane is very common in many machine shops, a large part of it comes down to the cost, overall ease of operation and general use case, in that it serves the needs of the shop quite well and is still quite cost effective without affecting or compromising its abilities. The list of components of the crane is small, the majority are static components with a few dynamic components, this makes it easy to service and maintain and reduces the likelihood of catastrophic failure as at any point in time very few components are working.
The static components are load bearing and are made up of the job/cantilever and the mast. These are singular pieces which make them easy to manufacture, install and service. This is particularly important for its cost, this simplicity makes it wasy to service in house which is good for its use case in small shops. The dynamic components are typically the pulleys, hoists and cabling and the bearings that facilitate the cantilever movement.
Now for the most these cranes are good but they are not without their dis-advantages, chief among them their mobility or specifically the lack of it. These cranes are usually floor or wall mounted, floor mounted cranes have a small foot print but they have limited reach, limited to the extent of the cantilever and the amount of rotation they have, their are some exceptions with wall monted jib cranes that can be mounted to rails on the wall which can allow for some greater amount of motion however they are limited by the reach of the cantilever. They also require special foundations to effectively anchor them which means special preparation of the shop floor. They are typically limited to smaller loads when compared to other cranes.
A common use case is within the machine shop environment, for the purpose of moving loads between, on and off stations, also helping to position loads while in use and getting loads on and off vehicles.
For such an application typical loads range from 0.25ton to 15tons, up to 20tons. The may be either freestanding or mast type. On viewing they both seem identical, however they are not entirely so, free standing cranes are just that with a singular point of contact with the floor at the base. Whereas the mast type is secured at the base and the top, with one or both points ultimately secured to the greater structure ofthe building, the other being secured to the foundation, typically bolted.
