A strut is a structural component commonly found in engineering , aeronautics , architecture and anatomy . Struts generally work by resisting longitudinal compression , but they may also serve in tension.
53-415: Part of the functionality of the clavicle is to serve as a strut between the scapula and sternum , resisting forces that would otherwise bring the upper limb close to the thorax . Keeping the upper limb away from the thorax is vital for its range of motion . Complete lack of clavicles may be seen in cleidocranial dysostosis , and the abnormal proximity of the shoulders to the median plane exemplifies
106-488: A coilover design in an automotive suspension . The coilover combines a shock absorber and a spring in a single unit. A common form of automotive suspension strut in an automobile is the MacPherson strut . MacPherson struts are often purchased by the automakers in sets of four completed sub-assemblies: These can be mounted on the car bodies as part of the manufacturers' own assembly operations. A MacPherson strut combines
159-557: A "double wishbone," suspension system which exclusively uses shock absorbers. Sports cars seem to favor this suspension style; however, the Porsche 911 favors traditional struts. Struts keeps your suspension aligned, along with numerous other functions. To check if a set of struts is failing; simply walk to each side of the wheel and begin to bounce the car up and down. As the car is pushed down, let it bounce back into position. If it continues to bounce up and down, consider taking your vehicle to
212-405: A bearing, but only for the cases, when the strut mounts operate as steering pivots. For such struts, the bearing is the wear item, as it is subject to constant impact of vibration and its condition reflects both wheel alignment and steering response. In vehicle suspension systems, struts are most commonly an assembly of coil-over spring and shock absorber. Other variants to using a coil-over spring as
265-410: A high shoulder position similar to that in modern humans . In dinosaurs , the main bones of the pectoral girdle were the scapula (shoulder blade) and the coracoid , both of which directly articulated with the clavicle. The clavicle was present in saurischian dinosaurs but largely absent in ornithischian dinosaurs. The place on the scapula where it articulated with the humerus (upper bone of
318-445: A high wing monoplane and act in tension during flight. Struts have also been widely used for purely structural reasons to attach engines, landing gear and other loads. The oil-sprung legs of retractable landing gear are still called Oleo struts . As components of an automobile chassis , struts can be passive braces to reinforce the chassis and/or body, or active components of the suspension. An example of an active unit would be
371-427: A mechanic for replacement. You can also check your strut car to see if it's leaking oil. Bad struts could possibly lead to many issues including the breaking of a wheel, flattening of a tire, damaged power steering, broken springs, broken joints, and many more issues in your suspension system. Keep all of these in mind as you drive your vehicle with bad struts. Clavicle The clavicle , collarbone , or keybone
424-436: A sense of a lighter duty piece: a king post carries a ridge beam but a king strut does not, a queen post carries a plate but a queen strut does not, a crown post carries a crown plate but a crown strut does not. Strutting or blocking between floor joists adds strength to the floor system. Struts provide outwards-facing support in their lengthwise direction, which can be used to keep two other components separate, performing
477-546: A significant structure in the front crash structure of the car, it is easier to engineer cars that pass more stringent small overlap crashes with struts, as opposed to those with a double wishbone suspension. Notable examples include the Honda Accord and Civic , as well as the Mercedes E-Class , all of which adopted struts to improve crash performance . The overall simplicity of the design also means there are fewer joints in
530-433: Is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavicle is the only long bone in the body that lies horizontally . Together with the shoulder blade, it makes up the shoulder girdle . It is a palpable bone and, in people who have less fat in this region,
583-408: Is also known as the acromial region, it is both the widest clavicular region and thinnest clavicular region. The lateral region of the shaft has two borders and two surfaces. The collarbone is the first bone to begin the process of ossification (laying down of minerals onto a preformed matrix) during development of the embryo , during the fifth and sixth weeks of gestation . However, it is one of
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#1732851389644636-419: Is also known as the sternal end. It is quadrangular and articulates with the clavicular notch of the manubrium of the sternum to form the sternoclavicular joint . The articular surface extends to the inferior aspect for articulation with the first costal cartilage . The lateral end is also known as the acromial end. It is flat from above downward. It bears a facet that articulates with the shoulder to form
689-473: Is an air strut which combines the shock absorber with an air spring and can be designed in the same fashion as a coilover device. These come available in most types of suspension setups including beam axle and MacPherson strut style design. Transportation-related struts are used in "load bearing" applications ranging from both highway and off-road suspensions to automobile hood and hatch window supports to aircraft wing supports. The majority of struts feature
742-416: Is associated with the pectoral fin ; they also have a bone called the cleithrum . In such fish, the paired clavicles run behind and below the gills on each side, and are joined by a solid symphysis on the fish's underside. They are, however, absent in cartilaginous fish and in the vast majority of living bony fish, including all of the teleosts . The earliest tetrapods retained this arrangement, with
795-420: Is both the widest clavicular region and thinnest clavicular region. The lateral end has a rough inferior surface that bears a ridge, the trapezoid line , and a slight rounded projection, the conoid tubercle (above the coracoid process ). These surface features are attachment sites for muscles and ligaments of the shoulder. It can be divided into three parts: medial end, lateral end, and shaft. The medial end
848-546: Is normally used for the front suspension only, where it provides a steering pivot as well as a suspension mounting for the wheel. The first production car to use MacPherson struts is often cited incorrectly as the French 1949 Ford Vedette , but it was developed before MacPherson, with an independent front suspension based on wishbones and an upper coil spring. Only in 1954, after the Vedette factory had been purchased by Simca , did
901-581: Is occasionally pierced by a branch of the supraclavicular nerve . In males the clavicle is usually longer and larger than in females. A study measuring 748 males and 252 females saw a difference in collarbone length between age groups 18–20 and 21–25 of about 6 and 5 mm (0.24 and 0.20 in) for males and females respectively. The left clavicle is usually longer and weaker than the right clavicle. The collarbones are sometimes partly or completely absent in cleidocranial dysostosis . The levator claviculae muscle , present in 2–3% of people, originates on
954-540: The Porsche 911 and Boxster . Geometric analysis shows the assembly cannot allow vertical movement of the wheel without some degree of either camber angle change, sideways movement, or both. It is not generally considered to give as good handling as a double wishbone or multi-link suspension, because it allows the engineers less freedom to choose camber change and roll center . Cars that have cockpit adjustable ride height generally cannot have MacPherson struts because of
1007-428: The acromioclavicular joint . The rounded medial region (sternal region) of the shaft has a long curve laterally and anteriorly along two-thirds of the entire shaft. The flattened lateral region (acromial region) of the shaft has an even larger posterior curve to articulate with the acromion of the scapula. The medial region is the longest clavicular region as it takes up two-thirds of the entire shaft. The lateral region
1060-434: The acromioclavicular joint . The area surrounding the joint gives an attachment to the joint capsule. The anterior border is concave forward and the posterior border is convex backward. The shaft is divided into two main regions, the medial region, and the lateral region. The medial region is also known as the sternal region, it is the longest clavicular region as it takes up two-thirds of the entire shaft. The lateral region
1113-428: The arm to the trunk of the body. Located directly above the first rib , it acts as a strut to keep the scapula in place so that the arm can hang freely. At its rounded medial end (sternal end), it articulates with the manubrium of the sternum (breastbone) at the sternoclavicular joint . At its flattened lateral end (acromial end), it articulates with the acromion , a process of the scapula (shoulder blade), at
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#17328513896441166-401: The gallbladder which is between the mid-clavicular line and the transpyloric plane . Clavicle fractures (colloquially, a broken collarbone) occur as a result of injury or trauma. The most common type of fractures occur when a person falls horizontally on the shoulder or with an outstretched hand. A direct hit to the collarbone will also cause a break. In most cases, the direct hit occurs from
1219-446: The radius arm . For those reasons, it has become almost ubiquitous with low cost manufacturers. Furthermore, it offers an easy method to set suspension geometry. Many modern versions replace the lower control arm with a wishbone. An anti-roll bar is optional and, if present, is attached by a ball-jointed rod to the spring-damper, or by a ball or elastomerically jointed rod to the wishbone. Because MacPherson struts are packaged with
1272-412: The 992-based 911 GT3, which uses a double wishbone. In recent years, General Motors and Ford have introduced a modified strut set-up, "Hi-Per Strut" and "Revoknuckle" respectively, that split the strut into two components that handle the up-and-down flexibility and steering dynamics separately. The benefits of this design are greater surface contact and reduction in torque steer. The drawbacks are
1325-507: The Chevrolet Cadet. The Cadet was poised to be a groundbreaking vehicle, and the three prototypes that had been built by 1946 displayed a wide range of innovations. One of these was a revolutionary new independent suspension system that featured what is now known as a MacPherson strut. The Cadet was slated to be the first production vehicle with MacPherson struts, but the project was cancelled in 1947 and never saw commercial production. This
1378-517: The addition of a diamond-shaped interclavicle between the base of the clavicles, although this is not found in living amphibians . The cleithrum disappeared early in the evolution of reptiles , and is not found in any living amniotes , but the interclavicle is present in most modern reptiles, and also in monotremes . In modern forms, however, there are a number of variations from the primitive pattern. For example, crocodilians and salamanders lack clavicles altogether (although crocodilians do retain
1431-515: The additional weight and cost, but it is less expensive than either a double wishbone or multi-link setup. Honda introduced another variation strut set-up, called "dual-axis" , which is used in the suspension design of the Civic Type-R . Another variant of the MacPherson strut is the double pivot front suspension, which splits the lower wishbone into two while retaining the standard upright design of
1484-623: The body is suspended, and the shock absorber , which is usually in the form of a cartridge mounted within the strut (see coilover ). The strut can also have the steering arm built into the lower outer portion. The whole assembly is very simple and can be pre-assembled into a unit. As well, the elimination of the upper control arm allows for more width in the engine compartment, which is useful for smaller cars, particularly with transverse -mounted engines, such as most front wheel drive vehicles have. The assembly can be further simplified, if needed, by substituting an anti-roll bar ( torsion bar ) for
1537-426: The bone stimulate the ossification of adjacent tissue. The resulting compact bone is known as a periosteal collar. The collarbone has a medullary cavity ( marrow cavity ) in its medial two-thirds. It is made up of spongy cancellous bone with a shell of compact bone . It is a dermal bone derived from elements originally attached to the skull. The shape of the clavicle varies more than most other long bones. It
1590-429: The camber changes that are an unavoidable part of the design. Ride suffers because the shock absorber has almost the same vertical motion as the wheel, so there is relatively little leverage to break the stiction in the seals. A standard single pivot MacPherson strut also tends to have positive scrub where the center of the steering axis is offset from the center of the front tires, which results in torque steer. Despite
1643-400: The clavicle's importance as a strut. Strut is a common name in timber framing for a support or brace of scantlings lighter than a post. Frequently struts are found in roof framing from either a tie beam or a king post to a principal rafter. Struts may be vertically plumb or leaning (then called canted, raking, or angled) and may be straight or curved. In the U.K., strut is generally used in
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1696-419: The compressible load bearer include support via pressurized nitrogen gas acting as the spring, and rigid (hard tail) support which provides neither longitudinal compression/extension nor damping. Struts were created in the 1970s in which automakers transitioned from large rear-wheeled drive vehicles to more fuel-efficient front-wheeled drive vehicles. The entire suspension system was changed in accordance to meet
1749-417: The drawbacks, the MacPherson strut set-up is still used on some high performance cars, because they tend to have relatively small suspension travel, and so do not have the same kinematic problems. Up until the 1989 model year (964), Porsche 911 used a similar strut design that did not have coil springs, using torsion bar suspension instead. Since then, all Porsche 911s have had front MacPherson struts, except
1802-441: The forelimb) is the called the glenoid . The clavicles fused in some theropod dinosaurs to form a furcula , which is the equivalent to a wishbone. In birds, the clavicles and interclavicle have fused to form a single Y-shaped bone, the furcula or "wishbone" which evolved from the clavicles found in coelurosaurian theropods. MacPherson strut The MacPherson strut is a type of automotive suspension system that uses
1855-414: The form and function of the pectoral girdle. One exception is the clavicle of AL 333x6/9 attributed to Australopithecus afarensis which has a well-preserved sternal end. One interpretation of this specimen, based on the orientation of its lateral end and the position of the deltoid attachment area, suggests that this clavicle is distinct from those found in extant apes (including humans), and thus that
1908-467: The interclavicle), while in turtles , they form part of the armoured plastron . The interclavicle is absent in marsupials and placental mammals . In many mammals, the clavicles are also reduced, or even absent, to allow the scapula greater freedom of motion, which may be useful in fast-running animals. Though a number of fossil hominin (humans and chimpanzees) clavicles have been found, most of these are mere segments offering limited information on
1961-426: The last bones to finish ossification at about 21–25 years of age. Its lateral end is formed by intramembranous ossification while medially it is formed by endochondral ossification . It consists of a mass of cancellous bone surrounded by a compact bone shell. The cancellous bone forms via two ossification centres , one medial and one lateral, which fuse later on. The compact forms as the layer of fascia covering
2014-399: The lateral side towards the medial side of the bone. The most common site of fracture is the junction between the two curvatures of the bone, which is the weakest point. This results in the sternocleidomastoid muscle lifting the medial aspect superiorly, which can result in perforation of the overlying skin. The clavicle first appears as part of the skeleton in primitive bony fish , where it
2067-426: The location of the bone is clearly visible. It receives its name from Latin clavicula 'little key' because the bone rotates along its axis like a key when the shoulder is abducted . The clavicle is the most commonly fractured bone. It can easily be fractured by impacts to the shoulder from the force of falling on outstretched arms or by a direct hit. The collarbone is a thin doubly curved long bone that connects
2120-424: The main functional airframe. Throughout the 1920s and 1930s they fell out of use in favour of the low drag cantilever construction. Most aircraft bracing struts are principally loaded in compression, with wires taking the tension loads. Lift struts came into increasing use during the changeover period and remain in use on smaller aircraft today where ultimate performance is not an issue. Typically, they are applied to
2173-489: The new style of vehicles. The new styles of vehicles left less room for the traditional system, which was called the short-arm/ long-arm suspension systems. This caused the MacPherson strut system to become the new standard for all automobiles including front-wheeled and rear-wheeled vehicles. The MacPherson strut system does not require an upper control arm, bushings, or a pivot shaft like previous models. Struts are not necessarily needed components on vehicles which separate
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2226-541: The opposite function of a tie . In piping, struts restrain movement of a component in one direction while allowing movement or contraction in another direction. Strut channel made from steel , aluminium , or fibre-reinforced plastic is used heavily in the building industry and is often used in the support of cable trays and other forms of cable management , and pipes support systems. Bracing struts and wires of many kinds were extensively used in early aircraft to stiffen and strengthen, and sometimes even to form,
2279-488: The pre-war Stout Scarab could have been an influence, and long-travel struts in aircraft landing gear were well known by that time. The French Cottin-Desgouttes utilized a similar design, albeit with less sophisticated leaf springs , but the Cottin-Desgouttes front suspension was in turn inspired by a 1904 design by American engineer J. Walter Christie . MacPherson designed the strut for all four wheels, but it
2332-424: The primary function of a shock absorber (as a damper ), with the ability to support sideways loads not along its axis of compression, somewhat similar to a sliding pillar suspension, thus eliminating the need for an upper suspension arm . This means that a strut must have a more rugged design, with mounting points near its middle for attachment of such loads. Another common type of strut used in air suspension
2385-527: The revised Simca Vedette switch to using front struts. Following MacPherson's arrival at Ford, the first production car to feature MacPherson struts was the British-built 1950 Ford Consul and the later Zephyr . A MacPherson strut uses a wishbone, or a substantial compression link stabilized by a secondary link, which provides a mounting point for the hub carrier or axle of the wheel. The lower arm system provides both lateral and longitudinal location of
2438-408: The shape of the human shoulder dates back to less than 3 to 4 million years ago . However, analyses of the clavicle in extant primates suggest that the low position of the scapula in humans is reflected mostly in the curvature of the medial portion of the clavicle rather than the lateral portion. This part of the bone is similar in A. afarensis and it is thus possible that this species had
2491-440: The springs and shock absorbers, while the shocks support no weight. There are also some vehicles with the option of only having one pair of struts on one set of wheels while the other pair uses a separate selection of shocks and springs. This singular pair of struts are almost always a MacPherson strut . These choices are made for various reasons including the balance of initial cost, performance, and other elements. Some vehicles use
2544-423: The steering axis at the bottom, to clear the tyre, which makes the bottom follow an arc when steering. The MacPherson strut benefited from introduction of unibody construction, because its design requires substantial vertical space and a strong top mount, which unibody construction can provide. Unibody construction also distributes suspension stresses. The strut will usually carry both the coil spring , on which
2597-492: The suspension to wear, so there is less decline in handling and steering feel over time . Inverted monotube struts can also provide extra rigidity in the front suspension, as seen in the Porsche 911 GT3 and Cayman GT4 , as well as the Subaru Impreza WRX STI . Finally, struts can package more efficiently than other types of front suspension, which allows for significant front cargo space in rear/mid-engined cars, such as
2650-437: The top of a telescopic damper as the upper steering pivot. It is widely used in the front suspension of modern vehicles. The name comes from American automotive engineer Earle S. MacPherson , who invented and developed the design. Earle S. MacPherson was appointed the chief engineer of Chevrolet's Light Car project in 1945. He was tasked with developing a new, smaller car for the immediate post-war market, an effort that led to
2703-447: The transverse processes of the upper cervical vertebrae and is inserted in the lateral half of the clavicle. The collarbone serves several functions: Muscles and ligaments that attach to the collarbone include: A vertical line drawn from the mid-clavicle called the mid-clavicular line is used as a reference in describing cardiac apex beat during medical examination. It is also useful for evaluating an enlarged liver, and for locating
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#17328513896442756-412: The wheel. The upper part of the hub carrier is rigidly fixed to the bottom of the outer part of the strut proper. That slides up and down the inner part of it, which extends upwards directly to a mounting in the body shell of the vehicle. The line from the top mount of the strut to the bottom ball joint on the control arm gives the steering axis inclination . The axis of the strut may be angled inwards from
2809-594: Was in large part due to GM's concerns about the Cadet's forecasted profit margins. After the Cadet project was shelved, a disgruntled MacPherson left GM to join Ford . Patents were filed in 1947 ( U.S. patent 2,624,592 for GM) and in 1949 ( U.S. patent 2,660,449 for Ford), with the latter patent citing designs by Guido Fornaca of FIAT in the mid-1920s. MacPherson's new strut design may have taken inspirations from other earlier designs as well. The strut suspension of
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