Jaw crushers are used as primary crushers, or the first step in the process of reducing rock. They crush primarily by using compression. The rock is dropped between two rigid pieces of metal, one of which then moves inwards towards the rock, and the rock is crushed because it has a lower breaking point than the opposing metal piece.
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A jaw or toggle crusher consists of a set of vertical jaws, one jaw being fixed and the other being moved back and forth relative to it by a cam or pitman mechanism. The jaws are farther apart at the top than at the bottom, forming a tapered chute so that the material is crushed progressively smaller and smaller as it travels downward until it is small enough to escape from the bottom opening. The movement of the jaw can be quite small, since complete crushing is not performed in one stroke. The inertia required to crush the material is provided by a weighted flywheel that moves a shaft creating an eccentric motion that causes the closing of the gap.
Single and double toggle jaw crushers are constructed of heavy duty fabricated plate frames with reinforcing ribs throughout. Manganese steel is used for both fixed and movable jaw faces. Heavy flywheels allow crushing peaks on tough materials. Double Toggle jaw crushers may feature hydraulic toggle adjusting mechanisms.
A sectional view of the single-toggle type of jaw crusher is shown below.In one respect, the working principle and application of this machine are similar to all types of rock crushers, the movable jaw has its maximum movement at the top of the crushing chamber, and minimum movement at the discharge point. The motion is, however, a more complex one than the Dodge motion, being the resultant of the circular motion of the eccentric shaft at the top of the swing jaw. combined with the rocking action of the inclined toggle plate at the bottom of this jaw. The motion at the receiving opening is elliptical; at the discharge opening, it is a thin crescent, whose chord is inclined upwardly toward the stationary jaw. Thus, at all points in the crushing chamber, the motion has both, vertical and horizontal, components.
It will be noted that the motion is a rocking one. When the swing jaw is rising, it is opening, at the top, during the first half of the stroke, and closing during the second half, whereas the bottom of the jaw is closing during the entire up-stroke. A reversal of this motion occurs during the downstroke of the eccentric.
The horizontal component of motion (throw) at the discharge point of the single-toggle jaw crusher is greater than the throw of the Dodge crusher at that point; in fact, it is about three-fourths that of Blake machines of similar short-side receiving-opening dimensions. The combination of favorable crushing angle, and nonchoking jaw plates, used in this machine, promotes a much freer action through the choke zone than that in the Dodge crusher. Capacities compare very favorably with comparable sizes of the Blake machine with non-choking plates, and permissible discharge settings are finer. A table of ratings is given.
The single-toggle type jaw crusher has been developed extensively. Because of its simplicity, lightweight, moderate cost, and good capacity, it has found quite a wide field of application in portable crushing rigs. It also fits into the small, single-stage mining operation much better than the slower Dodge type. Some years since this type was developed with very wide openings for reduction crushing applications, but it was not able to seriously challenge the gyratory in this field, especially when the high-speed modern versions of the latter type were introduced.
Due to the pronounced vertical components of motion in the single-toggle machine, it is obvious that a wiping action takes place during the closing strokes; either, the swing jaw must slip on the material, or the material must slip along the stationary jaw. It is inevitable that such action should result in accelerated wear of the jaw plates; consequently, the single-toggle crusher is not an economical machine for reducing highly abrasive, or very hard, tough rock. Moreover, the large motion at the receiving opening greatly accentuates shocks incidental to handling the latter class of material, and the full impact of these shocks must be absorbed by the bearings in the top of the swing jaw.
The single-toggle machine, like the Dodge type, is capable of making a high ratio-of-reduction, a faculty which enables it to perform a single-stage reduction of hand-loaded, mine run ore to a suitable ball mill, or rod mill, feed.
Within the limits of its capacity, and size of receiving openings, it is admirably suited for such operations. Small gravel plant operations are also suited to this type of crusher, although it should not be used where the gravel deposit contains extremely hard boulders. The crusher is easy to adjust, and, in common with most machines of the jaw type, is a simple crusher to maintain.
As rock particles are compressed between the inclined faces of the mantle and concaves there is a tendency for them to slip upward. Slippage occurs in all crushers, even in ideal conditions. Only the particles weight and the friction between it and the crusher surfaces counteract this tendency. In particular, very hard rock tends to slip upward rather than break. Choke feeding this kind of material can overload the motor, leaving no option but to regulate the feed. Smaller particles, which weigh less, and harder particles, which are more resistant to breakage, will tend to slip more. Anything that reduces friction, such as spray water or feed moisture, will promote slippage.
Leading is a technique for measuring the gap between fixed and moveable jaws. The procedure is performed while the crusher is running empty. A lead plug is lowered on a lanyard to the choke point, then removed and measured to find out how much thickness remains after the crusher has compressed it. This measures the closed side setting. The open side setting is equal to this measurement plus the throw of the mantle. The minimum safe closed side setting depends on:
Blake (Double Toggle) Originally the standard jaw crusher used for primary and secondary crushing of hard, tough abrasive rocks. Also for sticky feeds. Relatively coarse slabby product, with minimum fines.
Overhead Pivot (Double Toggle) Similar applications to Blake. Overhead pivot; reduces rubbing on crusher faces, reduces choking, allows higher speeds and therefore higher capacities. Energy efficiency higher because jaw and charge not lifted during cycle.
Overhead Eccentric (Single Toggle) Originally restricted to sampler sizes by structural limitations. Now in the same size of Blake which it has tended to supersede, because overhead eccentric encourages feed and discharge, allowing higher speeds and capacity, but with higher wear and more attrition breakage and slightly lower energy efficiency. In addition as compared to an equivalent double toggle, they are cheaper and take up less floor space.
Since the jaw crusher was pioneered by Eli Whitney Blake in the 2nd quarter of the 1800s, many have twisted the Patent and come up with other types of jaw crushers in hopes of crushing rocks and stones more effectively. Those other types of jaw crusher inventors having given birth to 3 groups:
Heavy-duty crushing applications of hard-to-break, high Work Index rocks do prefer double-toggle jaw crushers as they are heavier in fabrication. A double-toggle jaw crusher outweighs the single-toggle by a factor of 2X and well as costs more in capital for the same duty. To perform its trade-off evaluation, the engineering and design firm will analyze technical factors such as:
1. Proper selection of the jaws. 2. Proper feed gradation. 3. Controlled feed rate. 4. Sufficient feeder capacity and width. 5. Adequate crusher discharge area. 6. Discharge conveyor sized to convey maximum crusher capacity.
Although the image below is of a single-toggle, it illustrates the shims used to make minor setting changes are made to the crusher by adding or removing them in the small space between the crushers mainframe and the rea toggle block.
The jaw crusher discharge opening is the distance from the valley between corrugations on one jaw to the top of the mating corrugation on the other jaw. The crusher discharge opening governs the size of finished material produced by the crusher.
Crusher must be adjusted when empty and stopped. Never close crusher discharge opening to less than minimum opening. Closing crusher opening to less than recommended will reduce the capacity of crusher and cause premature failure of shaft and bearing assembly.
To compensate for wear on toggle plate, toggle seat, pitman toggle seat, and jaws additional shims must be inserted to maintain the same crusher opening. The setting adjustment system is designed to compensate for jaw plate wear and to change the CSS (closed side setting) of the jaw crusher. The setting adjustment system is built into the back frame end.
Here also the toggle is kept in place by a compression spring. Large CSS adjustments are made to the jaw crusher by modifying the length of the toggle. Again, shims allow for minor gap adjustments as they are inserted between the mainframe and the toggle block.
is done considering the maximum rock-lump or large stone expected to be crushed and also includes the TPH tonnage rate needing to be crushed. In sizing, we not that jaw crushers will only have around 75% availability and extra sizing should permit this downtime.
As a rule, the maximum stone-lump dimension need not exceed 80% of the jaw crushers gape. For intense, a 59 x 79 machine should not see rocks larger than 80 x 59/100 = 47 or 1.2 meters across. Miners being miners, it is a certainty during day-to-day operation, the crusher will see oversized ore but is should be fine and pass-thru if no bridging takes place.
It will be seen that the pitman (226) is suspended from an eccentric on the flywheel shaft and consequently moves up and down as the latter revolves, forcing the toggle plates outwards at each revolution. The seating (234) of the rear toggle plate (239) is fixed to the crusher frame; the bottom of the swing jaw (214) is therefore pushed forward each time the pitman rises, a tension rod (245) fitted with a spring (247) being used to bring it back as the pitman falls. Thus at each revolution of the flywheel the movable jaw crushes any lump of ore once against the stationary jaw (212) allowing it to fall as it swings back on the return half-stroke until eventually the pieces have been broken small enough to drop out. It follows that the size to which the ore is crushed.
The jaw crusher is not so efficient a machine as the gyratory crusher described in the next paragraph, the chief reason for this being that its crushing action is confined to the forward stroke of the jaw only, whereas the gyratory crusher does useful work during the whole of its revolution. In addition, the jaw crusher cannot be choke-fed, as can the other machine, with the result that it is difficult to keep it working at its full capacity that is, at maximum efficiency.
Tables 5 and 6 give particulars of different sizes of jaw crushers. The capacity figures are based on ore weighing 100 lb. per cubic foot; for a heavier ore, the figures should be increased in direct proportion to its weight in pounds per cubic foot.
The JAW crusher and the GYRATORY crusher have similarities that put them into the same class of crusher. They both have the same crushing speed, 100 to 200 R.P.M. They both break the ore by compression force. And lastly, they both are able to crush the same size of ore.
In spite of their similarities, each crusher design has its own limitations and advantages that differ from the other one. A Gyratory crusher can be fed from two sides and is able to handle ore that tends to slab. Its design allows a higher-speed motor with a higher reduction ratio between the motor and the crushing surface. This means a dollar saving in energy costs.
A Jaw crusher on the other hand requires an Ely wheel to store energy. The box frame construction of this type of crusher also allows it to handle tougher ore. This design restricts the feeding of the crusher to one side only.
The ore enters from the top and the swing jaw squeezes it against the stationary jaw until it breaks. The broken ore then falls through the crusher to be taken away by a conveyor that is under the crusher.Although the jaws do the work, the real heart of this crusher is the TOGGLE PLATES, the PITMAN, and the PLY WHEEL.
These jaw crushers are ideal forsmall properties and they are of the high capacity forced feed design.On this first Forced Feed Jaw Crusher, the mainframe and bumper are cast of special alloy iron and the initial cost is low. The frame is ribbed both vertically and horizontally to give maximum strength with minimum weight. The bumper is ruggedly constructed to withstand tremendous shock loads. Steel bumper can be furnished if desired. The side bearings are bronze; the bumper bearings are of the antifriction type.
This bearing arrangement adds both strength and ease of movement. The jaw plates and cheek plates are reversible and are of the best-grade manganese steel. The jaw opening is controlled by the position of an adjustable wedge block. The crusher is usually driven by a V-to-V belt drive, but it can be arranged for either V-to-flat or fiat belt drive. The 8x10 size utilizes a split frame and maybe packed for muleback transportation. Cast steel frames can be furnished to obtain maximum durability.
This second type of forced feed rock crusher is similar in design to the Type H listed above except for having a frame and bumper made of cast steel. This steel construction makes the unit lighter per unit of size and adds considerable strength. The bearings are all of the special design; they are bronze and will stand continuous service without any danger of failure. The jaw and cheek plates are manganese steel; and are completely reversible, thus adding to their wearing life. The jaw opening is controlled by the position of an adjustable wedge block. The crushers are usually driven by V-to-V but can be arranged for V-to-flat and belt drive. The 5x6 size and the 8x10 size can be made with sectionalized frame for muleback transportation. This crusher is ideal for strenuous conditions. Consider a multi jaw crusher.
Some jaw crushers are on-floor, some aboveground, and others underground. This in many countries, and crushing many kinds of ore. The Traylor Bulldog Jaw crusher has enjoyed world wide esteem as a hard-working, profit-producing, full-proof, and trouble-free breaker since the day of its introduction, nearly twenty years ago. To be modern and get the most out of your crushing dollars, youll need the Building breaker. Wed value the privilege of telling you why by letter, through our bulletins, or in person. Write us now today -for a Blake crusher with curved jaw plates that crush finer and step up production.
When a machine has such a reputation for excellence that buyers have confidence in its ability to justify its purchase, IT MUST BE GOOD! Take the Type G Traylor Jaw Crusher, for instance. The engineers and operators of many great mining companies know from satisfying experience that this machine delivers a full measure of service and yields extra profits. So they specify it in full confidence and the purchase is made without the usual reluctance to lay out good money for a new machine.
The success of the Type G Traylor Jaw Crusheris due to several characteristics. It is (1) STRONG almost to superfluity, being built of steel throughout; it is (2) FOOL-PROOF, being provided with our patented Safety Device which prevents breakage due to tramp iron or other causes of jamming; it is (3) ECONOMICAL to operate and maintain, being fitted with our well-known patented Bulldog Pitman and Toggle System, which saves power and wear by minimizing frictionpower that is employed to deliver increased production; it is (4) CONVENIENT to transport and erect in crowded or not easily accessible locations because it is sectionalized to meet highly restrictive conditions.
Whenever mining men need a crusher that is thoroughly reliable and big producer (which is of all time) they almost invariably think first of a Traylor Type G Jaw Crusher. By experience, they know that this machine has built into it the four essentials to satisfaction and profit- strength, foolproofness, economy, and convenience.
Maximum STRENGTH lies in the liberal design and the steel of which crushers parts are made-cast steel frame, Swing Jaw, Pitman Cap and Toggles, steel Shafts and Pitman rods and manganese steel Jaw Plates and Cheek Plates. FOOLPROOFNESS is provided by our patented and time-tested safety Device which prevents breakage due to packing or tramp iron. ECONOMY is assured by our well-known Bulldog Pitman and Toggle System, which saves power and wear by minimizing friction, the power that is used to deliver greater productivity. CONVENIENCE in transportation and erection in crowded or not easily accessible locations is planned for in advance by sectionalisation to meet any restrictive conditions.
Many of the worlds greatest mining companies have standardized upon the Traylor Type G Jaw Crusher. Most of them have reordered, some of them several times. What this crusher is doing for them in the way of earning extra dollars through increased production and lowered costs, it will do for you! Investigate it closely. The more closely you do, the better youll like it.
Have you ever wondered how contractors reduce large chunks of rock or concrete to size? Whether its creating aggregates or mining, jaw crushers are your go-to. Jaw crushers were created in 1858 by Eli Whitney Blake. And since then, theyve only become more widespread. This article will focus on what jaw crushers are and how theyre used in the professional setting.
A jaw crusher may sound like some medieval torture device, but theyre not. While they could be used to that effect, theyre more widely used in the areas of demolition and mining. A jaw crusher essentially crushes large rocks to a more usable size. Theyre typically the first-line machinery used in the material reduction for several applications. This includes rock quarries, sand and gravel, construction aggregates, metallurgy, and chemical industries. Jaw crushers are specifically designed to handle large feed and withstand abrasive material. Theyre at the forefront of sand, gravel, and mineral processing because of their effectiveness in breaking down large chunks.
Jaw crushers typically use the principles of compression and friction to break materials down. Theyre extremely powerful equipment that should be used with the utmost care. Jaw crushers are so powerful that theyve earned the moniker rock breakers because of their brute force.
All jaw crushers will have one fixed jaw and a moving one. These two form a V-shaped chamber, where the materials are fed. The movable jaw will move back and forth against the fixed one, compressing all materials in the space between. The mobile jaws movement will not be fixed from side-to-side. Instead, it moves in an elliptical motion with help from massively weighted flywheels.
As the moving jaw moves away from the fixed one, this creates a gap between the jaws. The discharge will fall through this gap, the size of which determines the size of the discharge. The gap size is often readily adjustable to suit whatever purpose for rock breaking.
Double toggle jaw crushers are the classic style of jaw crushers. Theyre also popularly known as the Blake type because of their similar mechanism to the original jaw crusher by Eli Whitney Blake. For a long time, this has been the standard for breaking abrasive and hard materials, having been used for over a century. This variation has a higher energy-efficiency as well as a longer useful life. Double toggle jaw crushers use only pressure (less friction) to break large and hard materials.
Single toggle jaw crushers have grown quite popular over the past few years. Compared to the double toggle ones, the primary downside of single toggle jaw crushers is that their feed capacity was quite small before. This is because single toggle machines are much more compact, thus accepting smaller feed sizes. But its good to know that this problem has mostly been solved due to technological advancements. These days, single toggle jaw crushers are highly valued because of how quickly they process materials. This comes at a cost, though, as this variation tends to wear much quicker than the other. This is in part due to the fact that single toggle jaw crushers also heavily utilize friction to break materials down. So, it should come as good news that the parts that wear easily are readily available and not too expensive.
For nearly 40 years Cutting Technologies (CTI) has been the go-to demolition contractor for technically demanding, one-off jobs. Our wealth of experience enables CTI to bring outside-of-the-block approaches to achieve the impossible. Contractors trust CTI to get the job done right. Take a look at our demolition services on our website.
Terrence Tan Tingis an industrial engineer by profession but a full time writer by passion. He loves to write about a wide range of topics from many different industries thanks to his undying curiosity.
If you are a rock, sand, gravel, or mineral processing industry veteran or an avid reader of our blog, you know that there are several different types and styles of crushing equipment. The exact crushers you needjaw, cone, impact, or gyratorywill depend on your site, the product youre making, and how much you need to produce.
An individual crushers construction and capabilities also dictate where in your processing operations it will fit. That is, you may have multiple types of crushers situated in primary, secondary, and tertiary stations in a circuit format to perform the necessary material reduction work. Each type of crusher brings unique strengths and benefits to the process.
Todays post focuses on compression-style jaw crushers, which are most often employed in the primary stage of a crushing circuit. Its important to know that cone crushers are sometimes used in their place, and well also talk a little bit about when cone crushers may be preferred over jaw crushers.
As we introduced in a recent blog post about all the different types of crushing equipment available, jaw crushers are sometimes also referred to as rock breakers, which speaks to their brute force. They are almost exclusively used as primary crushers because they excel at breaking up some of the largest and hardest materials into more manageable pieces for further reduction by different crushing equipment. Jaw crushers have a multitude of advantages, including:
Due to their smaller physical size, jaw crushers are also ideal for tight spaces, such as underground mining and mobile crushing applications, where some other primary crushing solutions simply do not fit.
Jaw crushers have been around for nearly 200 years at this point and are one of the most historic crusher types. Because of this, jaw crushers have advanced technologically through the years to make them more durable and to improve their movement to reduce choking and increase operational speed. These design tweaks over time have perfected a machine thats simple enough in its working principle that it may never truly become obsolete.
Double toggle movement jaw crushers like the Blake style (named for the inventor of the first successful mechanical jaw crusher, Eli Whitney Blake), have long been the standard used for crushing hard and abrasive rocks, as well as sticky feeds. These jaw crushers have high energy efficiency. The overhead pivot design further reduces wear and tear on crusher faces versus the Blake style.
More compact than double toggle designs, the single toggle movement jaw crusher was at one time unable to accept such large feed sizes, though it can typically run faster. Technological innovations solved the feed size issue, and now these machines are quite popular for how quickly they work. They do experience a bit more wear and tear than the double toggle style crushers, however. Of course, wear parts are widely available and economical, so this fact has not prevented the single toggle design from catching on.
As we touched on above, different jaw crusher designs will operate slightly differently, but how they work is similar across the board. All jaw crushers reduce large sized rocks, ore, or other material by a compression action. A fixed jaw, mounted in a V-shaped alignment, is the stationary breaking surface, while a movable, swing jaw exerts force on the feed material by pushing it against the stationary plate.
The space at the bottom of the V-aligned jaw plates is the output gap that dictates the size of the crushed product from the jaw crusher. The rock remains in the jaws until it is small enough to pass through the gap.
While jaw crushers may always be a smart primary crusher stage choice for many operations, its true that newer cone crushers are increasingly taking their place due to versatility. Cone crushers and jaw crushers both work by compression, reducing materials by squeezing them until they break apart.
The benefit that cone crushers offer over jaw crushers is their ability to output a more cubical product similar to impact crushers. Cone crushers have traditionally been used as secondary and sometimes tertiary crushing stations.
Its true that crushers are customizable to help you extract material, break it down into usable product, and get it to market most economically and efficiently. The best way to find the right crushers for your unique operation is to work with a knowledgeable material handling solutions partner like Kemper Equipment. Get in touch with us today to learn how a custom-designed crushing circuit or a few new crushers can boost your productivity and transform your operations.
One of the most commonly used crushing machine is the jaw crusher. It is a heavy-duty machine that is generally used for crushing different kinds of raw materials into smaller pieces. The jaw crushers can be seen in the mining and disposal industry where large rocks need to be crushed into smaller pieces for further use.
The working principle of the jaw crushers is very simple. Powered by a diesel or gas motor, the jaw crusher brakes materials in a crushing chamber. The materials are pushed inside the chamber from the top opening and when crushed they are released through the bottom opening. The crushing power of the jaw crushers depends on the size of the chamber. The bigger the chamber, the more powerful the jaw crusher. The crushing process can be basically explained as a process where the materials are sandwiched between two jaw plates. The movable jaw plates squeeze and crush the materials into several small pieces.
There are two main types of jaw crushers: double toggle and overhead eccentric jaw crusher. The only difference between these two crushers is the location of the pivot joint. In the overhead eccentric jaw crushers, the pivot joint is located at the bottom of the chamber, while at the double toggle crushers, the pivot joint is on the top. The double toggle jaw crushers are more preferred, simply because these crushers are described as fuel-efficient and easy to operate machines.
The jaw crushers can be used for crushing all kinds of hard materials quickly and efficiently. Powerful and highly efficient, the jaw crushers are essential pieces of equipment in the construction and mining industry. They can be used in combination with other crushing machines for more efficient performance. In most cases, the jaw crushers are used as primary crushing machines in projects where high quality materials are not needed.
Known as a bon vivant, Edward doesn't just amaze people with his passion for life's luxuries but also with his vast interests and talent as a writer; not surprisingly his motto is: "If you want to have limitless inspiration for writing, you have to live life first!". Whether it's all-things car related or travel adventures, he tackles with each and every topic, including those that have to do with arts, industries, tech gadgets, business and, believe it or not, love and romance!