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130-444: The force is applied on a flat, broad surface. This energy is transported to the pointy, sharp end of the wedge, hence the force is transported. The wedge simply transports energy in the form of friction and collects it to the pointy end, consequently breaking the item. Wedges have existed for thousands of years. They were first made of simple stone. Perhaps the first example of a wedge is the hand axe (see also Olorgesailie ), which

260-520: A conchoidal fracture . With early hand axes, it is easy to improvise their manufacture, correct mistakes without requiring detailed planning, and no long or demanding apprenticeship is necessary to learn the necessary techniques. These factors combine to allow these objects to remain in use throughout pre-history. Their adaptability makes them effective in a variety of tasks, from heavy duty such as digging in soil, felling trees or breaking bones to delicate such as cutting ligaments, slicing meat or perforating

390-524: A lithic reduction sequence may be used as tools. (Other biface typologies make five divisions rather than four. ) French antiquarian André Vayson de Pradenne introduced the word biface in 1920. This term co-exists with the more popular hand axe ( coup de poing ), that was coined by Gabriel de Mortillet much earlier. The continued use of the word biface by François Bordes and Lionel Balout supported its use in France and Spain, where it replaced

520-530: A bifacial item and many bifacial items are not hand axes. Nor were hand axes and bifacial items exclusive to the Lower Palaeolithic period in the Old World. They appear throughout the world and in many different pre-historical epochs, without necessarily implying an ancient origin. Lithic typology is not a reliable chronological reference and was abandoned as a dating system. Examples of this include

650-431: A concave surface and a conical head; both surfaces are typically lined with manganese steel surfaces. The inner cone has a slight circular movement, but does not rotate; the movement is generated by an eccentric arrangement. As with the jaw crusher, material travels downward between the two surfaces being progressively crushed until it is small enough to fall out through the gap between the two surfaces. A gyratory crusher

780-436: A criterion of mate choice." Miller followed their example and said that hand axes have characteristics that make them subject to sexual selection, such as that they were made for over a million years throughout Africa, Europe and Asia, they were made in large numbers, and most were impractical for utilitarian use. He claimed that a single design persisting across time and space cannot be explained by cultural imitation and draws

910-454: A crusher to reduce oversize material too large for a crusher. Crushers are used to reduce particle size enough so that the material can be processed into finer particles in a grinder. A typical processing line at a mine might consist of a crusher followed by a SAG mill followed by a ball mill . In this context, the SAG mill and ball mill are considered grinders rather than crushers. In operation,

1040-684: A cultural or ritual use. Miller thinks that the most important clue is that under electron microscopy hand axes show no signs of use or evidence of edge wear. Others argue that little evidence for use-wear simply relates to the particular sedimentological conditions, rather than being evidence of discarding without use. It has been noted that hand axes can be good handicaps in Zahavi 's handicap principle theory: learning costs are high, risks of injury, they require physical strength, hand-eye coordination, planning, patience, pain tolerance and resistance to infection from cuts and bruises when making or using such

1170-430: A hand axe. The use-wear analysis of Palaeolithic hand axes is carried out on findings from emblematic sites across nearly all of Western Europe. Keeley and Semenov were the pioneers of this specialized investigation. Keeley stated, " The morphology of typical hand axes suggests a greater range of potential activities than those of flakes " . Many problems need to be overcome in carrying out this type of analysis. One

1300-399: A jagged and uneven surface. Applying surface force ( pressure ) results in unpredictable and typically non-cubical resulting particles. Utilizing velocity rather than surface force allows the breaking force to be applied evenly both across the surface of the rock as well as through the mass of the rock. Rock, regardless of size, has natural fissures (faults) throughout its structure. As rock

1430-452: A metal surface to break or compress materials into small fractional chunks or denser masses. Throughout most of industrial history, the greater part of crushing and mining part of the process occurred under muscle power as the application of force concentrated in the tip of the miners pick or sledge hammer driven drill bit. Before explosives came into widespread use in bulk mining in the mid-nineteenth century, most initial ore crushing and sizing

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1560-629: A parallel between bowerbirds ' bowers (built to attract potential mates and used only during courtship) and Pleistocene hominids ' hand axes. He called hand axe building a "genetically inherited propensity to construct a certain type of object." He discards the idea that they were used as missile weapons because more efficient weapons were available, such as javelins . Although he accepted that some hand axes may have been used for practical purposes, he agreed with Kohn and Mithen who showed that many hand axes show considerable skill, design and symmetry beyond that needed for utility. Some were too big, such as

1690-418: A pick. Economies of scale gradually infused industrial enterprises, while transport became a key bottleneck as the volume of moved materials continued to increase following demand. This spurred numerous canal projects, inspired laying first wooden, then iron protected rails using draft animals to pull loads in the emerging bulk goods transportation dependent economy. In the coal industry, which grew as coal became

1820-631: A road surface. This removes the need for hauling oversized material to a stationary crusher and then back to the road surface. Additionally, Small/Mini Crushers (approx 6,000 to 60,000 pound range) are portable crushers typically used by travelling from jobsite-to-jobsite. These small crusher may be track or wheel mounted, gas, diesel, or electrically powered, but are primarily of the Jaw Crusher variety. The following table describes typical uses of commonly used crushers: A jaw crusher uses compressive force for breaking of particle. This mechanical pressure

1950-481: A sharp border all around. Other uses seem to show that hand axes were a multi-functional tool, leading some to describe them as the "Acheulean Swiss Army knife ". Other academics have suggested that the hand axe was simply a byproduct of being used as a core to make other tools, a weapon, or was perhaps used ritually. Wells proposed in 1899 that hand axes were used as missile weapons to hunt prey – an interpretation supported by Calvin , who suggested that some of

2080-551: A site in Baise , China shows that hand axes were made in eastern Asia. Hand axe technology is almost unknown in Australian prehistory, although a few have been found. Experiments in knapping have demonstrated the relative ease with which a hand axe can be made, which could help explain their success. In addition, they demand relatively little maintenance and allow a choice of raw materials–any rock will suffice that supports

2210-440: A straight border. An experienced flintknapper needs less than 15 minutes to produce a good quality hand axe. A simple hand axe can be made from a beach pebble in less than 3 minutes. The manufacturing process employs lithic reduction . This phase is commonly thought of as the most important in hand axe fabrication, although it is not always used, such as for hand axes made from flakes or a suitable tool stone. An important concern

2340-503: A suitable tool stone, but they rarely show evidence of retouching . Later hand axes were improved by the use of the Levallois technique to make the more sophisticated and lighter Levallois core. In summary, hand axes are recognized by many typological schools under different archaeological paradigms and are quite recognisable (at least the most typical examples). However, they have not been definitively categorized. Stated more formally,

2470-403: A technical analysis of their manufacture and a morphological analysis. The technical analysis of a hand axe tries to discover each of the phases in its chaîne opératoire (operational sequence). The chain is highly flexible, as a toolmaker may focus narrowly on just one of the sequence's links or equally on each link. The links examined in this type of study start with the extraction methods of

2600-432: A variety of materials. Later examples of hand axes are more sophisticated with their use of two layers of knapping (one made with stone knapping and one made with bone knapping). Lastly, a hand axe represents a prototype that can be refined giving rise to more developed, specialised and sophisticated tools such as the tips of various projectiles, knives, adzes and hatchets. Given the typological difficulties in defining

2730-402: A variety of shapes, including circular, triangular and elliptical—calling in to question the contention that they had a constant and only symbolic significance. They are typically between 8 and 15 cm (3 and 6 in) long, although they can be bigger or smaller. They were typically made from a rounded stone , a block or lithic flake , using a hammer to remove flakes from both sides of

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2860-530: Is 'thrown' by a VSI rotor against a solid anvil, it fractures and breaks along these fissures. Final particle size can be controlled by 1) the velocity at which the rock is thrown against the anvil and 2) the distance between the end of the rotor and the impact point on the anvil. The product resulting from VSI crushing is generally of a consistent cubical shape such as that required by modern Superpave highway asphalt applications. Using this method also allows materials with much higher abrasiveness to be crushed than

2990-510: Is a compact geometry and size which is valuable in mining industry, .e.g. in underground hard-rock mining . A crusher bucket is an attachment for hydraulic excavators. Its way of working consists on a bucket with two crushing jaws inside, one of them is fixed and the other one moves back and forth relative to it, as in a jaw crusher . They are manufactured with a high inertia power train, circular jaw movement and an anti-stagnation plate, which prevents large shredding pieces from getting stuck in

3120-406: Is a pointed area at one end, cutting edges along its side and a rounded base (this includes hand axes with a lanceolate and amygdaloidal shape as well as others from the family). The axes are almost always symmetrical, despite studies showing that symmetry doesn't help in tasks such as using a hand axe for skinning animals. While there is a "typical" shape to most hand axes, there are some displaying

3250-410: Is achieved by the two jaws of the crusher of which one is fixed while the other reciprocates. A jaw or toggle crusher consists of a set of vertical jaws, one jaw is kept stationary and is called a fixed jaw while the other jaw called a swing jaw, moves back and forth relative to it, by a cam or pitman mechanism, acting like a class II lever or a nutcracker . The volume or cavity between the two jaws

3380-588: Is added to its variety of forms [...] we realise that the hand axe is one of the most problematical and complex objects in Prehistory In 1969 in the 2nd edition of World Prehistory, Grahame Clark proposed an evolutionary progression of flint-knapping industries (also known as complexes or technocomplexes ) in which the "dominant lithic technologies" occurred in a fixed sequence where simple Oldowan one-edged tools were replaced by these more complex Acheulean hand axes, which were then eventually replaced by

3510-444: Is applied to cement mill, mining, building construction, road &bridge construction, railway construction and metallurgy and some other industries. Multi-cylinder hydraulic cone crusher is mainly composed of main frame, eccentric shaft, crushing cone, mantle, bowl liner, adjusting device, dust ring, transmission device, bowl-shaped bearing, adjusting sleeve, hydraulic control system, hydraulic safety system, etc. The electric motor of

3640-519: Is applied to medium crushing. The medium type is applied to fine crushing. The short head type is applied to coarse fine crushing. As casting steel technique is adopted, the machine has good rigidity and large high strength. Single cylinder hydraulic cone crusher is mainly composed of main frame, transmission device, eccentric shaft, bowl-shaped bearing, crushing cone, mantle, bowl liner, adjusting device, adjusting sleeve, hydraulic control system, hydraulic safety system, dust-proof ring, feed plate, etc. It

3770-757: Is basically mechanical, and apart from the colour and the wear it has the same characteristics as the interior in terms of hardness , toughness etc. However, flint is surrounded by a limestone cortex that is soft and unsuitable for stone tools. As hand axes are made from a tool stone's core, it is normal to indicate the thickness and position of the cortex in order to better understand the techniques that are required in their manufacture. The variation in cortex between utensils should not be taken as an indication of their age. Many partially-worked hand axes do not require further work in order to be effective tools. They can be considered to be simple hand axes. Less suitable tool stone requires more thorough working. In some specimens

3900-664: Is called the crushing chamber. The movement of the swing 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 flywheel that moves a shaft creating an eccentric motion that causes the closing of the gap. Jaw crushers are heavy duty machines and hence need to be robustly constructed. The outer frame is generally made of cast iron or steel. The jaws themselves are usually constructed from cast steel. They are fitted with replaceable liners which are made of manganese steel, or Ni-hard (a Ni-Cr alloyed cast iron). Jaw crushers are usually constructed in sections to ease

4030-428: Is capable with an HSI and most other crushing methods. VSI crushers generally utilize a high speed spinning rotor at the center of the crushing chamber and an outer impact surface of either abrasive resistant metal anvils or crushed rock. Utilizing cast metal surfaces 'anvils' is traditionally referred to as a "shoe and anvil VSI". Utilizing crushed rock on the outer walls of the crusher for new rock to be crushed against

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4160-419: Is combined in one tool. Given the right circumstances, it is possible to make use of loose flakes . In the same book, Keeley states that a number of the hand axes studied were used as knives to cut meat (such as hand axes from Hoxne and Caddington ). He identified that the point of another hand axe had been used as a clockwise drill . This hand axe came from Clacton-on-Sea (all of these sites are located in

4290-464: Is easily identifiable and was carried out using techniques such as the coup de tranchet (French, meaning " tranchet blow"), or simply with scale or scalariform retouches that alter an edge's symmetry and line. With its flattened-teardrop symmetry, the Achulean handaxe has long invited cognitive explanations. It is the earliest hominid tool that seems "designed" in some modern sense. Yet, for most of

4420-429: Is generally an indication of the age when a tool was made and with other archaeological data can provide a context that allows its age to be estimated. Crusher A crusher is a machine designed to reduce large rocks into smaller rocks, gravel , sand or rock dust. Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled , or to reduce

4550-510: Is important to study the rock's grain, texture, the presence of joints, veins, impurities or shatter cones etc. In order to study the use of individual items it is necessary to look for traces of wear such as pseudo-retouches, breakage or wear, including areas that are polished. If the item is in a good condition it is possible to submit it to use-wear analysis , which is discussed in more detail below. Apart from these generalities, which are common to all carved archaeological pieces, hand axes need

4680-814: Is known as the Acheulean . The use of hand axes survived the Middle Palaeolithic in a much smaller area and were especially important during the Mousterian , up to the middle of the Last glacial period . [In Europe s]mall bifaces are found from the late Acheulean until the Aurignacian Hand axes dating from the lower Palaeolithic were found on the Asian continent, on the Indian subcontinent and in

4810-401: Is made by chipping stone, generally flint , to form a bifacial edge, or wedge. A wedge is a simple machine that transforms lateral force and movement of the tool into a transverse splitting force and movement of the workpiece. The available power is limited by the effort of the person using the tool, but because power is the product of force and movement, the wedge amplifies the force by reducing

4940-497: Is mainly used in mining, chemical industry, road and bridge construction, building, etc. As for VSC series cone crusher, there are four crushing cavities (coarse, medium, fine and superfine) to choose. Compared with the same type, VSC series cone crusher, whose combination of crushing frequency and eccentricity is the best, can make materials have higher comminution degree and higher yield. In addition, VSC series cone crusher's enhanced laminating crushing effect on material particles makes

5070-415: Is necessary to detach a 'starting flake', often much larger than the rest of the flakes (due to the oblique angle of a rounded pebble requiring greater force to detach it), thus creating an asymmetry. Correcting the asymmetry by removing material from the other faces, encouraged a more pointed (oval) form factor. (Knapping a completely circular hand axe requires considerable correction of the shape.) Studies in

5200-399: Is one of the main types of primary crushers in a mine or ore processing plant. Gyratory crushers are designated in size either by the gape and mantle diameter or by the size of the receiving opening. Gyratory crushers can be used for primary or secondary crushing. The crushing action is caused by the closing of the gap between the mantle line (movable) mounted on the central vertical spindle and

5330-444: Is similar in operation to a gyratory crusher, with less steepness in the crushing chamber and more of a parallel zone between crushing zones. A cone crusher breaks rock by squeezing the rock between an eccentrically gyrating spindle, which is covered by a wear-resistant mantle, and the enclosing concave hopper, covered by a manganese concave or a bowl liner. As rock enters the top of the cone crusher, it becomes wedged and squeezed between

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5460-444: Is the application of the same force over a wider area of the material to be separated. Other examples of wedges are found in drill bits , which produce circular holes in solids. The two edges of a drill bit are sharpened, at opposing angles, into a point and that edge is wound around the shaft of the drill bit. When the drill bit spins on its axis of rotation, the wedges are forced into the material to be separated. The resulting cut in

5590-399: Is the difficulty in observing larger pieces with a microscope. Of the millions of known pieces and despite their long role in human history, few have been thoroughly studied. Another arises from the clear evidence that the same tasks were performed more effectively using utensils made from flakes: This raises the question: why make hand axes, whose production is more complicated and costly, if

5720-513: Is the implement that has been used to form the biface. If multiple implements were used, it is essential to discover in what order they were used and the result obtained by each one. The most common implements are: Hand axes can be made without subsequent reworking of the edges. A hammerstone was the most common percussive tool used during the Acheulean. The resulting artefact is usually easily recognizable given its size and irregular edges, as

5850-489: Is the longest-used tool in human history . It is made from stone, usually flint or chert that has been "reduced" and shaped from a larger piece by knapping , or hitting against another stone. They are characteristic of the lower Acheulean and middle Palaeolithic ( Mousterian ) periods, roughly 1.6 million years ago to about 100,000 years ago, and used by Homo erectus and other early humans, but rarely by Homo sapiens . Their technical name ( biface ) comes from

5980-496: Is the same in Dutch where the expression used is vuistbijl which literally means "fist axe". The same locution occurs in other languages. However, the general impression of these tools was based on ideal (or classic) pieces that were of such perfect shape that they caught the attention of non-experts. Their typology broadened the term's meaning. Biface hand axes and bifacial lithic items are distinguished. A hand axe need not be

6110-449: Is traditionally referred to as "rock on rock VSI". VSI crushers can be used in static plant set-up or in mobile tracked equipment. Mineral sizers are a variety of roll crushers which use two rotors with large teeth, on small diameter shafts, driven at a low speed by a direct high torque drive system. This design produced three-stage breaking action which all interact when breaking materials using sizer technology. Their primary advantage

6240-402: Is useful as it assists in pushing the particles through the crushing chamber. This phenomenon leads to higher capacity of the single toggle jaw crushers but it also results in higher wear of the crushing jaws. These type of jaw crushers are preferred for the crushing of softer particles. In the double toggle jaw crushers, the oscillating motion of the swing jaw is caused by the vertical motion of

6370-683: The Hoabinhian . However, Movius' hypothesis was proved incorrect when many hand axes made in Palaeolithic era were found in 1978 at Hantan River, Jeongok, Yeoncheon County , South Korea for the first time in East Asia. Some of them are exhibited at the Jeongok Prehistory Museum, South Korea. The Padjitanian culture from Java was traditionally thought to be the only oriental culture to manufacture hand axes. However,

6500-724: The Neolithic and Chalcolithic periods. These tools are similar to more modern adzes and were a cheaper alternative to polished axes. The modern day villages along the Sepik river in New Guinea continue to use tools that are virtually identical to hand axes to clear forest. "The term biface should be reserved for items from before the Würm II-III interstadial ", although certain later objects could exceptionally be called bifaces. Hand axe does not relate to axe , which

6630-401: The fluvial terraces of Western Europe . This means that different strategies were required for the procurement and use of available resources. The supply of materials was the most important factor in the manufacturing process as Palaeolithic artisans were able to adapt their methods to available materials, obtaining adequate results from even the most difficult raw materials. Despite this it

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6760-404: The idealised model combines a series of well-defined properties , but no set of these properties are necessary or sufficient to identify a hand axe. The study of hand axes is made complicated because its shape is the result of a complicated chain of technical actions that are only occasionally revealed in their later stages. If this complexity of intentions during the manufacture of a hand axe

6890-417: The "Swiss Army knife" multipurpose suite of proposed uses (deflesh- ing, scraping, pounding roots, and flake source), an easy-to-make shape would suffice – and indeed the simpler tools continued to be made. None of these uses adequately addresses the "design aspects." Why is the handaxe mostly symmetric, why mostly flattened, why the seldom-sharp point, why sharpened all around (when that interferes with gripping

7020-854: The "quasi-bifaces" that sometimes appear in strata from the Gravettian , Solutrean and Magdalenian periods in France and Spain, the crude bifacial pieces of the Lupemban culture ( 9000 B.C. ) or the pyriform tools found near Sagua La Grande in Cuba . The word biface refers to something different in English than biface in French or bifaz in Spanish, which could lead to many misunderstandings. Bifacially carved cutting tools, similar to hand axes, were used to clear scrub vegetation throughout

7150-416: The 1990s at Boxgrove , in which a butcher attempted to cut up a carcass with a hand axe, revealed that the hand axe was able to expose bone marrow . Kohn and Mithen independently arrived at the explanation that symmetric hand axes were favoured by sexual selection as fitness indicators . Kohn in his book As We Know It wrote that the hand axe is "a highly visible indicator of fitness, and so becomes

7280-494: The Americas used antler wedges for splitting and working wood to make canoes , dwellings and other objects. Wedges are used to lift heavy objects, separating them from the surface upon which they rest. Consider a block that is to be lifted by a wedge. As the wedge slides under the block, the block slides up the sloped side of a wedge. This lifts the weight F B of the block. The horizontal force F A needed to lift

7410-545: The El Basalito site in Salamanca , where excavation uncovered fragments of a hand axe with marks at the tip that appeared to be the result of the action of a wedge, which would have subjected the object to high levels of torsion that broke the tip. A break or extreme wear can affect a tool's point or any other part. Such wear was reworked by means of a secondary working as discussed above. In some cases this reconstruction

7540-571: The Maritime Academy handaxe or the "Great Hand Axe" found in Furze Platt, England that is 30.6 cm long (other scholars measure it as 39.5 cm long). Some were too small - less than two inches. Some were "overdetermined", featuring symmetry beyond practical requirements and showing evidence of unnecessary attention to form and finish. Some were actually made out bone instead of stone and thus were not very practical, suggesting

7670-640: The Middle East (to the south of parallel 40° N), but they were absent from the area to the east of the 90° E meridian . Movius designated a border (the so-called Movius Line ) between the cultures that used hand axes to the west and those that made chopping tools and small retouched lithic flakes , such as were made by Peking Man and the Ordos culture in China, or their equivalents in Indochina such as

7800-412: The advantage of reliable construction, high productivity, better granularity and shape of finished products, easy adjustment and lower operational costs. The spring release system of a cone crusher acts an overload protection that allows tramp to pass through the crushing chamber without damage to the crusher. Compound cone crusher (VSC series cone crusher) can crush materials of over medium hardness . It

7930-506: The application of these machines. Mobile crushers are versatile and efficient machines designed for on-site crushing in mining and construction, offering flexibility and mobility to process materials directly at the job site. Mobile crushers are available in various types and configurations: Mobile Jaw Crushers: These crushers feature a stationary jaw and a movable jaw, enabling primary crushing of materials with varying hardness and abrasiveness. Mobile Impact Crushers: Impact crushers utilize

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8060-403: The basic methods of material size reduction; impact, compression, attrition, and cutting. Depending on the material properties and desired outcome some methods of crushing and thus machines designs may be more appropriate for the use case. Typically, crushing stages are followed by milling stages if the materials need to be further reduced. Additionally rock breakers are typically located next to

8190-695: The best specimens come from 1.2 mya deposits in Olduvai Gorge . By 1.8 mya early man was present in Europe. Remains of their activities were excavated in Spain at sites in the Guadix-Baza basin and near Atapuerca. Most early European sites yield "mode 1" or Oldowan assemblages. The earliest Acheulean sites in Europe appear around 0.5 mya. In addition, the Acheulean tradition did not spread to Eastern Asia. In Europe and particularly in France and England,

8320-426: The block is obtained by considering the velocity of the wedge v A and the velocity of the block v B . If we assume the wedge does not dissipate or store energy, then the power into the wedge equals the power out. Or The velocity of the block is related to the velocity of the wedge by the slope of the side of the wedge. If the angle of the wedge is α then which means that the mechanical advantage Thus,

8450-590: The blocks in the crushing chamber when the machine is suddenly stuffy. Thus the maintenance rate is greatly reduced and production efficiency is greatly improved as it can remove blocks without disassembling the machine. Impact crushers involve the use of impact rather than pressure to crush material. The material is contained within a cage, with openings on the bottom, end, or side of the desired size to allow pulverized material to escape. There are two types of impact crushers: horizontal shaft impactor and vertical shaft impactor. The HSI crushers break rock by impacting

8580-400: The bottom of the door and the wedge, and the wedge and the floor (or other surface). The mechanical advantage or MA of a wedge can be calculated by dividing the height of the wedge by the wedge's width: The more acute , or narrow, the angle of a wedge, the greater the ratio of the length of its slope to its width, and thus the more mechanical advantage it will yield. A wedge will bind when

8710-540: The bucket's mouth, not allowing them to enter the crushing jaws. They have also the crushing jaws placed in a cross position. This position together with its circular motion gives these crusher buckets the faculty of grinding wet material. For the most part advances in crusher design have moved slowly. Jaw crushers have remained virtually unchanged for sixty years. More reliability and higher production have been added to basic cone crusher designs that have also remained largely unchanged. Increases in rotating speed have provided

8840-402: The chimney— 'all the rage'  among the growing middle-class and affluence of the sixteenth-and-seventeenth centuries;and as always, the charcoal needed to smelt metals, especially to produce ever larger amounts of brass and bronze , pig iron , cast iron and wrought iron demanded by the new consumer classes. Other metallurgical developments such as silver and gold mining mirrored

8970-411: The concave liners (fixed) mounted on the main frame of the crusher. The gap is opened and closed by an eccentric on the bottom of the spindle that causes the central vertical spindle to gyrate. The vertical spindle is free to rotate around its own axis. The crusher illustrated is a short-shaft suspended spindle type, meaning that the main shaft is suspended at the top and that the eccentric is mounted above

9100-435: The cone crusher drives the eccentric shaft to make periodic swing movement under the shaft axis, and consequently surface of mantle approaches and leaves the surface of bowl liner now and then, so that the material is crushed due to squeezing and grinding inside the crushing chamber. The safety cylinder of the machine can ensure safety as well as lift supporting sleeve and static cone by a hydraulic system and automatically remove

9230-493: The core as the irregularities formed during knapping are not removed. The notches obtained were exploited in the production sequence. It is common that this type of manufacture yields " partial bifaces " (an incomplete working that leaves many areas covered with cortex), "unifaces" (tools that have only been worked on one face), " bifaces in the Abbevillian style " and " nucleiform bifaces " . This type of manufacturing style

9360-463: The cortex is unrecognisable due to the complete working that it has undergone, which has eliminated any vestige of the original cortex. It is possible to distinguish multiple types of hand axe: Older hand axes were produced by direct percussion with a stone hammer and can be distinguished by their thickness and a sinuous border. Mousterian hand axes were produced with a soft billet of antler or wood and are much thinner, more symmetrical and have

9490-424: The crushing chamber. Foreign objects, such as steel , can cause extensive damage to a cone crusher, and additional costs in lost production. The advance of hydraulic relief systems has greatly reduced downtime and improved the life of these machines. Due to safety requirements and the weight of the jaws, many companies and OEM providers have produced a suite of lifting tools to safely install and fit these tools into

9620-419: The cubic shape of crushed materials better, which increases the selling point. Symons cone crusher (spring cone crusher) can crush materials of above medium hardness. And it is widely used in metallurgy, building, hydropower, transportation, chemical industry, etc. When used with jaw crusher, it can be used as secondary, tertiary or quaternary crushing. Generally speaking, the standard type of Symons cone crusher

9750-474: The degree to which they fragment the starting material, with primary and secondary crushers handling coarse materials, and tertiary and quaternary crushers reducing ore particles to finer gradations. Each crusher is designed to work with a certain maximum size of raw material, and often delivers its output to a screening machine which sorts and directs the product for further processing. As well as size, machines designed for each of these stages must take into account

9880-634: The development of knives for those kinds of tasks. The blade of the knife allowed humans to cut meat, fibers, and other plant and animal materials with much less force than it would take to tear them apart by simply pulling with their hands. Other examples are plows , which separate soil particles, scissors which separate fabric, axes which separate wood fibers, and chisels and planes which separate wood. Wedges, saws and chisels can separate thick and hard materials, such as wood, solid stone and hard metals and they do so with much less force, waste of material, and with more precision, than crushing , which

10010-667: The east of England). Toth reached similar conclusions for pieces from the Spanish site in Ambrona ( Soria ). Analysis carried out by Domínguez-Rodrigo and co-workers on the primitive Acheulean site in Peninj ( Tanzania ) on a series of tools dated 1.5 mya shows clear microwear produced by plant phytoliths , suggesting that the hand axes were used to work wood. Among other uses, use-wear evidence for fire making has been identified on dozens of later Middle Palaeolithic hand axes from France , suggesting Neanderthals struck these tools with

10140-490: The essence of a hand axe, it is important when analysing them to take account of their archaeological context ( geographical location , stratigraphy , the presence of other elements associated with the same level , chronology etc.). It is necessary to study their physical state to establish any natural alterations that may have occurred: patina, shine, wear and tear, mechanical, thermal and / or physical-chemical changes such as cracking, in order to distinguish these factors from

10270-562: The even more complex Mousterian tools made with the Levallois technique . The oldest known Oldowan tools were found in Gona, Ethiopia . These are dated to about 2.6 mya. Early examples of hand axes date back to 1.6 mya in the later Oldowan (Mode I), called the "developed Oldowan " by Mary Leakey . These hand axes became more abundant in mode II Acheulean industries that appeared in Southern Ethiopia around 1.4 mya. Some of

10400-407: The fact that the archetypical model is a generally bifacial (with two wide sides or faces) and almond -shaped (amygdaloidal) lithic flake . Hand axes tend to be symmetrical along their longitudinal axis and formed by pressure or percussion. The most common hand axes have a pointed end and rounded base, which gives them their characteristic almond shape, and both faces have been knapped to remove

10530-421: The features of jaw and cone crushers, offering versatility and efficiency for processing diverse materials in various applications. VSI crushers use a different approach involving a high speed rotor with wear resistant tips and a crushing chamber designed to 'throw' the rock against. The VSI crushers utilize velocity rather than surface force as the predominant force to break rock. In its natural state, rock has

10660-528: The flakes can do the same work with the same efficiency? The answer could be that, in general, hand axes were not conceived for a particular function (excluding certain specialized types) [...], they were not made for one main task but covered a much more general purpose. Keeley based his observations on archaeological sites in England. He proposed that in base settlements where it was possible to predict future actions and where greater control on routine activities

10790-589: The fledgling furnace company and wrested control of it, and by 1615 managed to have James I issue a proclamation forbidding the use of wood to produce glass, giving his family's extensive coal holdings a monopoly on both source and means of production for nearly half-a-century. Abraham Darby a century later relocated to Bristol where he had established a building brass and bronze industry by importing Dutch workers and using them to raid Dutch techniques. Both materials were considered superior to iron for cannon, and machines as they were better understood. But Darby would change

10920-481: The further cutting of trees for charcoal in larger and larger regions in the United Kingdom. In 1611, a consortium led by courtier Edward Zouch was granted a patent for the reverberatory furnace , a furnace using coal, not precious national timber reserves, which was immediately employed in glass making. An early politically connected and wealthy Robber Baron figure Sir Robert Mansell bought his way into

11050-600: The gear. The short-shaft design has superseded the long-shaft design in which the eccentric is mounted below the gear. With the rapid development of mining technology, the cone crusher can be divided into four types: compound cone crusher, spring cone crusher, hydraulic cone crusher and gyratory crusher. According to different models, the cone crusher is divided into vertical shaft cone (VSC) series cone crusher (compound cone crusher), Symons cone crusher, PY cone crusher, single cylinder hydraulic cone crusher, multi-cylinder hydraulic cone crusher, gyratory crusher, etc. A cone crusher

11180-444: The grain. A narrow wedge with a relatively long taper , used to finely adjust the distance between objects is called a gib, and is commonly used in machine tool adjustment. The tips of forks and nails are also wedges, as they split and separate the material into which they are pushed or driven; the shafts may then hold fast due to friction. The blade is a compound inclined plane, consisting of two inclined planes placed so that

11310-460: The hand axe was not itself a tool, but a large lithic core from which flakes had been removed and used as tools (flake core theory). On the other hand, there are many hand axes found with retouching such as sharpening or shaping, which casts doubt on this idea. Other theories suggest the shape is part tradition and part by-product of its manufacture. Many early hand axes appear to be made from simple rounded pebbles (from river or beach deposits). It

11440-470: The item. This hammer can be made of hard stone, or of wood or antler . The latter two, softer hammers can produce more delicate results. However, a hand axe's technological aspect can reflect more differences. For example, uniface tools have only been worked on one side and partial bifaces retain a high proportion of the natural cortex of the tool stone , often making them easy to confuse with chopping tools . Further, simple bifaces may have been created from

11570-438: The large pieces to a size which can be handled by the downstream machinery. Some crushers are mobile and can crush rocks as large as 1.5 meter (60 inches). Primarily used in-pit at the mine face these units are able to move with the large infeed machines (mainly shovels) to increase the tonnage produced. In a mobile road operation, these crushed rocks are directly combined with concrete, and asphalt which are then deposited on to

11700-470: The largest variation. For instance, a 48-inch (120 cm) cone crusher manufactured in 1960 may be able to produce 170 tons/h of crushed rock, whereas the same size crusher manufactured today may produce 300 tons/h. These production improvements come from speed increases and better crushing chamber designs. The largest advance in cone crusher reliability has been seen in the use of hydraulics to protect crushers from being damaged when uncrushable objects enter

11830-400: The mantle and the bowl liner or concave. Large pieces of ore are broken once, and then fall to a lower position (because they are now smaller) where they are broken again. This process continues until the pieces are small enough to fall through the narrow opening at the bottom of the crusher. A cone crusher is suitable for crushing a variety of mid-hard and above mid-hard ores and rocks. It has

11960-415: The material is crushed progressively smaller and smaller as it travels downward until it is small enough to escape from the bottom opening. The Dodge jaw crusher has a variable feed area and a fixed discharge area which leads to choking of the crusher and hence is used only for laboratory purposes and not for heavy duty operations. A gyratory crusher is similar in basic concept to a jaw crusher, consisting of

12090-401: The material is in the direction of rotation of the drill bit, while the helical shape of a bit allows the removal of the cut material. Wedges can also be used to hold objects in place, such as engine parts ( poppet valves ), bicycle parts ( stems and eccentric bottom brackets ), and doors . A wedge-type door stop (door wedge) functions largely because of the friction generated between

12220-417: The mineral pyrite to produce sparks at least 50,000 years ago. Some hand axes were used with force that left clearly visible marks. Other visible marks can be left as the scars from retouching, on occasion it is possible to distinguish them from marks left by the initial manufacture. One of the most common cases is when a point breaks. This was seen at sites in Europe, Africa and Asia. One example comes from

12350-523: The mines went, the larger the demand became for better pumps, the greater the demand for iron, the greater the need for coal, the greater the demand for each. Seeing ahead clearly, Darby, sold off his brass business interests and relocated to Coalbrookdale with its plentiful coal mines, water power and nearby ore supplies. Over that decade his foundries developed iron casting technologies and began to supplant other metals in many applications. He adapted Coking of his fuel by copying Brewers practices. In 1822,

12480-522: The movement. This amplification, or mechanical advantage is the ratio of the input speed to output speed. For a wedge, this is given by 1/tanα, where α is the tip angle. The faces of a wedge are modeled as straight lines to form a sliding or prismatic joint . The origin of the wedge is not known. In ancient Egyptian quarries , bronze wedges were used to break away blocks of stone used in construction. Wooden wedges that swelled after being saturated with water were also used. Some indigenous peoples of

12610-490: The natural cortex , at least partially. Hand axes are a type of the somewhat wider biface group of two-faced tools or weapons. Hand axes were the first prehistoric tools to be recognized as such: the first published representation of a hand axe was drawn by John Frere and appeared in a British publication in 1800. Until that time, their origins were thought to be natural or supernatural. They were called thunderstones , because popular tradition held that they had fallen from

12740-668: The oldest hand axes appear after the Beestonian Glaciation – Mindel Glaciation , approximately 750,000 years ago, during the so-called Cromerian complex . They became more widely produced during the Abbevillian tradition. The apogee of hand axe manufacture took place in a wide area of the Old World , especially during the Riss glaciation , in a cultural complex that can be described as cosmopolitan and which

12870-451: The pitman. The pitman moves up and down. The swing jaw closes, i.e., it moves towards the fixed jaw when the pitman moves upward and opens during the downward motion of the pitman. This type is commonly used in mines due to its ability to crush tough and abrasive materials. In the Dodge type jaw crushers, the jaws are farther apart at the top than at the bottom, forming a tapered chute so that

13000-462: The planes meet at one edge. When the edge where the two planes meet is pushed into a solid or fluid substance, it overcomes the resistance of materials to separate by transferring the force exerted against the material into two opposing forces normal to the faces of the blade. The blade's first known use by humans was the sharp edge of a flint stone that was used to cleave or split animal tissue, e.g. cutting meat. The use of iron or other metals led to

13130-603: The practices and developments of the bulk material handling methods and technologies feeding the burgeoning appetite for more and more iron and glass, both of which were rare in personal possessions until the 1700s. Things only became worse when the English figured out how to cast the more economical iron cannons (1547), following on their feat of becoming the armorers of the European continent's powers by having been leading producers of brass and bronze guns, and eventually by various acts of Parliament, gradually banned or restricted

13260-424: The preferred fuel for smelting ores, crushing and preparation (cleaning) was performed for over a hundred years in coal breakers , massive noisy buildings full of conveyors, belt-powered trip-hammer crushing stages and giant metal grading/sorting grates. Like mine pumps, the internal conveyors and trip-hammers were housed within these 7—11 storey buildings. Mining operations use crushers, commonly classified by

13390-412: The present day. The gradual coming of that era and displacement of the cottage industry based economies was itself accelerated first by the utility of wrought and cast iron as a desired materials giving impetus to larger operations, then in the late-sixteenth century by the increasing scarcity of wood lands for charcoal production to make the newfangled window glass material that had become—along with

13520-617: The principle of rapid impact to crush materials, making them suitable for secondary and tertiary crushing of various rocks and minerals. Mobile Cone Crushers: Cone crushers employ a cone-shaped crushing chamber, ideal for producing finely crushed aggregates and sands for construction and mining applications. Mobile Vertical Shaft Impact (VSI) Crushers: VSI crushers utilize a high-speed rotor with wear-resistant tips to crush materials, offering superior shaping capabilities for producing high-quality aggregates with excellent particle shape. Mobile Jaw and Cone Combination Crushers: These crushers combine

13650-416: The process transportation if they are to be taken underground for carrying out the operations. Jaw crushers are classified on the basis of the position of the pivoting of the swing jaw The Blake crusher was patented by Eli Whitney Blake in 1858. The Blake type jaw crusher has a fixed feed area and a variable discharge area. Blake crushers are of two types- single toggle and double toggle jaw crushers. In

13780-464: The pumping industries needs for larger cylinders met up with Darby's ability to melt sufficient quantities of pig iron to cast large inexpensive iron cylinders instead of costly brass ones, reducing the cost of cylinders by nine-tenths. With gunpowder being increasingly applied to mining, rock chunks from a mining face became much larger, and the blast dependent mining itself had become dependent upon an organized group, not just an individual swinging

13910-446: The raw material (of various sizes) is usually delivered to the primary crusher's hopper by dump trucks , excavators or wheeled front-end loaders . A feeder device such as an apron feeder, conveyor or vibrating grid controls the rate at which this material enters the crusher, and often contains a preliminary screening device which allows smaller material to bypass the crusher itself, thus improving efficiency. Primary crushing reduces

14040-401: The raw material, then include the actual manufacture of the item, its use, maintenance throughout its working life, and finally its disposal. A toolmaker may put a lot of effort into finding the highest quality raw material or the most suitable tool stone. In this way more effort is invested in obtaining a good foundation, but time is saved on shaping the stone: that is, the effort is focused on

14170-408: The removed flakes leave pronounced percussion bulbs and compression rings. A hammerstone produces a small number of flakes that are wide and deep leaving long edges on the tool as their highly concave form yields curving edges. The cross-section is irregular, often sub-rhombic, while the intersection between the faces forms an acute angle of between 60° and 90° degrees. The shape is similar to that of

14300-445: The rock with hammers that are fixed upon the outer edge of a spinning rotor. HSI machines are sold in stationary, trailer mounted and crawler mounted configurations. HSI's are used in recycling, hard rock and soft materials. In earlier years the practical use of HSI crushers is limited to soft materials and non abrasive materials, such as limestone , phosphate , gypsum , weathered shales , however improvements in metallurgy have changed

14430-576: The rounder specimens of Acheulean hand axes were used as hunting projectiles or as "killer frisbees" meant to be thrown at a herd of animals at a water hole so as to stun one of them. This assertion was inspired by findings from the Olorgesailie archaeological site in Kenya . Few specimens indicate hand axe hafting , and some are too large for that use. However, few hand axes show signs of heavy damage indicative of throwing, modern experiments have shown

14560-401: The scars left during the tool's manufacture or use. The raw material is an important factor, because of the result that can be obtained by working it and in order to reveal the economy and movement of prehistoric humans. In the Olduvai Gorge the raw materials were most readily available some ten kilometres from the nearest settlements. However, flint or silicate is readily available on

14690-421: The signs of use. Hand axes are mainly made of flint , but rhyolites , phonolites , quartzites and other coarse rocks were used as well. Obsidian , natural volcanic glass, shatters easily and was rarely used. Most researchers think that handaxes were primarily used as cutting tools. The pioneers of Palaeolithic tool studies first suggested that bifaces were used as axes despite the fact that they have

14820-450: The single toggle jaw crushers, the swing jaw is suspended on the eccentric shaft which leads to a much more compact design than that of the double toggle jaw crusher. The swing jaw, suspended on the eccentric, undergoes two types of motion- swing motion towards the fixed jaw due to the action of toggle plate and vertical movement due to the rotation of the eccentric. These two motions, when combined, lead to an elliptical jaw motion. This motion

14950-469: The size of a solid mix of raw materials (as in rock ore ), so that pieces of different composition can be differentiated. Crushing is the process of transferring a force amplified by mechanical advantage through a material made of molecules that bond together more strongly, and resist deformation more, than those in the material being crushed do. Crushing devices hold material between two parallel or tangent solid surfaces, and apply sufficient force to bring

15080-583: The sky during storms or were formed inside the earth by a lightning strike and then appeared at the surface. They are used in some rural areas as an amulet to protect against storms. Handaxes are generally thought to have been primarily used as cutting tools, with the wide base serving as an ergonomic area for the hand to grip the tool, though other uses, such as throwing weapons and use as social and sexual signaling have been proposed. The four classes of hand axe are: While Class 4 hand axes are referred to as "formalized tools", bifaces from any stage of

15210-406: The smaller the angle α the greater the ratio of the lifting force to the applied force on the wedge. This is the mechanical advantage of the wedge. This formula for mechanical advantage applies to cutting edges and splitting operations, as well as to lifting. They can also be used to separate objects, such as blocks of cut stone. Splitting mauls and splitting wedges are used to split wood along

15340-436: The start of the Acheulean period and became more common with time. Manufacturing a hand axe from a flake is actually easier than from a pebble. It is also quicker, as flakes are more likely to be closer to the desired shape. This allows easier manipulation and fewer knaps are required to finish the tool; it is also easier to obtain straight edges. When analysing a hand axe made from a flake, it should be remembered that its shape

15470-448: The start of the operational chain. Equally the artisan may concentrate the most effort in the manufacture so that the quality or suitability of the raw material is less important. This will minimize the initial effort, but will result in a greater effort at the end of the operational chain. Hand axes are most commonly made from rounded pebbles or nodules, but many are also made from a large flake. Hand axes made from flakes first appeared at

15600-416: The surface, chunks that were eventually also to lead to rails and mine railways transporting bulk aggregations that post-mine face crushing became widely necessary. The earliest of these were in the foundries, but as coal took hold the larger operations became the coal breakers that fueled industrial growth from the first decade of the 1600s to the replacement of breakers in the 1970s through the fuel needs of

15730-437: The surfaces together to generate enough energy within the material being crushed so that its molecules separate from (fracturing), or change alignment in relation to (deformation), each other. The earliest crushers were hand-held stones, where the weight of the stone provided a boost to muscle power, used against a stone anvil. Querns and mortars are types of these crushing devices. In industry, crushers are machines which use

15860-701: The technique to often result in flat-faced landings, and many modern scholars consider the "hurling" theory to be poorly conceived but so attractive that it has taken a life of its own. As hand axes can be recycled, resharpened and remade, they could have been used for varied tasks. For this reason it may be misleading to think of them as axes , they could have been used for tasks such as digging, cutting, scraping, chopping, piercing and hammering. However, other tools, such as small knives, are better suited for some of these tasks, and many hand axes have been found with no traces of use. Baker suggested that since so many hand axes have been found that have no retouching, perhaps

15990-532: The term hand axe . Use of the expression hand axe has continued in English as the equivalent of the French biface ( bifaz in Spanish), while biface applies more generally for any piece that has been carved on both sides by the removal of shallow or deep flakes. The expression Faustkeil is used in German ; it can be literally translated as hand axe, although in a stricter sense it means "fist wedge". It

16120-486: The tool for pounding uses)? Neither does a suite of uses suggest why this form could remain the same from southern Africa to northern Europe to eastern Asia – and resist cultural drift for so long. The handaxe technique and its rationale were surely lost many times, just as Tasmanians lost fishing and fire-starting practices. So how did Homo erectus keep rediscovering the enigmatic handaxe shape, over and over for nearly 1.5 million years? The most characteristic and common shape

16250-442: The wedge included angle is less than the arctangent of the coefficient of friction between the wedge and the material. Therefore, in an elastic material such as wood, friction may bind a narrow wedge more easily than a wide one. This is why the head of a splitting maul has a much wider angle than that of an axe. Hand axe A hand axe (or handaxe or Acheulean hand axe ) is a prehistoric stone tool with two faces that

16380-805: The world in several key ways. Where the Dutch had failed in casting iron, one of Darby's apprentices, John Thomas succeeded in 1707 and as Burke put it: "had given England the key to the Industrial Revolution" . At the time, mines and foundries were virtually all small enterprises except for the tin mines (driven by the price and utility of brass) and materials came out of the mines already hammered small by legions of miners who had to stuff their work into carry sacks for pack animal slinging. Concurrently, mines needed drainage resulting in Savery and Newcomen's early steam driven pumping systems. The deeper

16510-466: Was by hand and hammers at the mine or by water powered trip hammers in the small charcoal fired smithies and iron works typical of the Renaissance through the early-to-middle Industrial Revolution . It was only after explosives, and later early powerful steam shovels produced large chunks of materials, chunks originally reduced by hammering in the mine before being loaded into sacks for a trip to

16640-502: Was common, the preferred tools were made from specialized flakes, such as racloirs , backed knives, scrapers and punches. However, hand axes were more suitable on expeditions and in seasonal camps, where unforeseen tasks were more common. Their main advantage in these situations was the lack of specialization and adaptability to multiple eventualities. A hand axe has a long blade with different curves and angles, some sharper and others more resistant, including points and notches. All of this

16770-414: Was overused in lithic typology to describe a wide variety of stone tools. At the time the use of such items was not understood. In the particular case of Palaeolithic hand axes the term axe is an inadequate description. Lionel Balout stated, "the term should be rejected as an erroneous interpretation of these objects that are not 'axes ' ". Subsequent studies supported this idea, particularly those examining

16900-441: Was predetermined (by use of the Levallois technique or Kombewa technique or similar). Notwithstanding this, it is necessary to note a tool's characteristics: type of flake, heel, knap direction. The natural external cortex or rind of the tool stone, which is due to erosion and the physical-chemical alterations of weathering , is different from the stone's interior. In the case of chert , quartz or quartzite , this alteration

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