The History Of Jaw Crusher
The first jaw crusher was invented by Eli Whitney Blake. It was named and patented the Blake crusher in 1858. In crusher, Blake employed a toggle which was the principal mechanism of the crusher. Today jaw crushers are used in carrying out heavy duty material crushing services. Every other jaw crusher built till this moment have borrowed knowledge on that which Blake originally built. Jaws of the crusher that he built are rectangular in shape integrated with a crushing chamber and fixed jaws. On top of these components is the pitman and the eccentric shaft.
A jaw crusher is one of different types of crushers often used in crushing rocks, mining s well as in a plant where ore is being processed. In order to break and crush particles, the jaw crusher makes use of what is known to be a compressive force. A jaw crusher is powered either by a diesel or electric motor meaning that operations can be executed within remote regions devoid of adequate electricity supply. Crushing takes place when a material is passed in the feed and then is being crushed all the way down through the discharge room of the crusher , stored and can be taken for a secondary crushing phase. The presence of a pitman is highly necessary for a jaw crusher to execute its tasks.
A pitman is a firm shaft connecting a piston and a crank in an engine with a reciprocating motion. It is also known as a connecting rod. A piston on the other hand is fitted by firm rings into a cylinder with a purpose of transferring force from the expansion in the cylinder to the shaft. Certain engines sometimes substitute the valve for a piston. What the pitman specifically does is to convert from one motion to another by a pushing force.
It is the most used and popular crusher in the world today. A jaw crusher usually comes with a set of vertical jaws with two plates namely:
the stationary or fixed jaw plate: as the name implies, the plate is static and does not move
the moving or swing jaw plate: it is placed right on the pitman with a powerful motion that reciprocates
Jaw crushers are ruggedly, robustly and strongly built owing to the fact that they are heavy duty. Both the jaws of the crusher and the body of the crusher itself are built with steel. Because of these components, it is preferable to build them in segments especially in situations where they will have to be carried to execute underground operations.
There exists two types of jaw crushers
single toggle crusher: otherwise known as the overhead eccentric due to the fact that it has an above placement of its shaft. It makes use of a compressing swing to keep toggle in place. This type of crusher can be fed only from a single side. The swing jaw reaches its highest movement right the top of the crushing room while the lowest movement is attained at the dissipating point.
It is considered to be a complex motion because once the swing jaw rises, it creates an opening right on the top placement during the first stroke and collapses during the second whereas the jaw that sits at the bottom closes during this rising stroke. Although this type of crusher has lesser shafts with a single toggle that moves away from the bottom of the swinging jaw to a static point behind the jaw crusher. Most of its operation are done in an up and down movement.
The pitman in this type of crusher is mounted on top and shielded by the toggle plate. Unlike the double toggle crushers, they are capable of accepting a better range of feeds. Besides this capability, it is has a more compact build due to the suspension of its swing jaw; a swing jaw that takes two motions- a flip motion that comes in contact with the fixed or stationary jaw due to its toggle plate action and a vertical motion as a result of the eccentric rotation. However, when these two motions are coalesced, they lead to what we call the Elliptical jaw motion. This motion specifically helps to move crushed particles through to the discharge area. Single toggle jaw crushers are mostly preferred for crushing soft particles.
double toggle crusher: it is more powerful, larger and heavier with more parts than the single toggle crusher. In this type of crusher, more emphasis is placed on the location of the eccentric which in most cases is found right at the back of the swinging jaw. This type of crusher protects the eccentric from harm of rock or other particles that are crushed.
The fluctuating motion in the toggle crusher is provoked by a vertical movement of the pitman. In this operation, the pitman goes all the way up and then comes back down. The swing jaw of the double toggle crusher closes up by contacting the fixed jaw during the pitman's upward movement and opens up during its(the pitman)downward movement. This crusher is extensively used by miners due to its prowess to pulverize tough particles and materials like ferroalloys and glass, lime stone, granite, black rock, iron ore, rive gravel, emery, bauxite, quartzite, cupriferous slag, calcium carbide and so on.
There is an absence of a rotary movement in this crusher since crushing is carried out by compressing materials being fed between the firm jaw plates. The swing plate undertakes a compression towards the static jaw. The jaw plates of the double toggle crusher can either be plane smooth or jagged.
It usually comes with in different sizes and horse power drive with the lowest hose power drive at 20hp and minimum size of 12 X 7 inches respectively. The crusher speed can have as high as 500rpm(rotation per minute) and can deliver a breath taking 3000 tons of particles per minute.
The type of crusher to use depends on the kind of operation that is to be carried out from soft operations to medium and hard. Jaw crushers can be purchased from the electric tool shop or from our website for as little as $1,000-8,000. At the same time, we also provide complete production line construction and EPC services.