Bumpers
Bumpers are made of heavy sheet metal or plastic and are mounted on the front and rear of the car. Bumpers are bent and formed into specific shapes in order to absorb and deliver momentum during a collision. In the event of a collision, the bumper absorbs some of the impact, which decreases damage to the car and its occupants. It also protects the front of the car by diverting all of the car's momentum to the object with which it has collided.
The bumper's job is to minimize damage, primarily to the occupants of the vehicle and to the vehicle itself. Sometimes bumpers are constructed with built-in "crumple zones." Crumple zones are designed to absorb impact; they will flex on impact. As the metal flexes, the action of the bending metal converts the kinetic energy of the car into heat. Kinetic energy is the energy an object possesses while it is in motion.
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Doors/ Door Locks
A door consists of an inner and an outer panel. The inner panel provides strength. The outer panel is just a metal cover, or "skin." The inner panel has a variety of holes and stems for the attachment to the window mechanisms and locks. The upper part of the door is the window glass that rides in grooves on two sides of the door frame.
Door locks must keep the door from opening in a crash situation and resist break-ins, but it should also be possible to open them if you lose the key. The door handle acts as a lever that pulls on a rod. The rod rotates the door latch. The various types of lock mechanisms interrupt the action of the door latch. The "striker" is a mechanism attached to the door post, or part of the car body. It holds the door shut or allows it to be opened when the door handle rotates the latch. The striker's job is to keep the door closed under normal conditions, or to hold the door closed if the door post starts to bend away from the door in a crash.
Power door lock mechanisms are operated by electric solenoids. Anti-burst door locks are a relatively cheap development, that have proven to be one of the most successful but unrecognized benefits of crash protective design. Studies have shown that it is much better to remain in a car than to be thrown out, because if a person is thrown out, serious injury may result from contact with the road surface, and there is a great risk of being run over by one's own or another vehicle. It is, therefore, important that the doors should stay shut during a collision, and the design of a latch to do this has been perfected and introduced into almost all cars in the world.
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Firewall
The firewall separates the passenger and engine sections of the car. It's a flat piece of steel stamped with curves and punched with holes and openings for wires, tubes, and levers that extend into the passenger compartment. It goes up both sides of the dashboard and stops where it meets the roof panel. These pillars formed by the firewall provide the frame for the windshield and are called "A" pillars.
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Frame (Chassis)
The frame provides a firm structure for the body, as well a good anchor point for the suspension system. There are two types of frames; integral frames and conventional frames.
A conventional frame is basically a "one-piece" frame, or two "one-piece" frames fastened together. The frame is extremely rigid in order to keep all the other parts of the car in perfect alignment. The manufacturer takes this type of frame and attaches all the other parts of the car to it, like the way a sculptor starts with a wire frame to build his sculpture on and give it shape. To keep things smooth, rubber insulator blocks, or "pads" are placed between the frame and the other car parts. Because the conventional frame is so important to the structure of your car, (without it, your car would be a pile of doors, hoses, seats, wires and metal) it is usually constructed of heavy steel and welded or cold riveted together.
The integral, or unibody, frame is just the opposite. With this type of frame, the body parts are used to structurally strengthen the entire car, and all of the sections are welded into one piece. Sometimes the parts of the body and the suspension system are attached and reinforced. Also, some unibody frames have partial front and rear frames for attaching the engine and suspension members.
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Hood
The car's hood is another type of door. It also consists of an inner and an outer panel. The inner panel provides strength. The outer panel is just a metal cover, or "skin". The underside of the hood is often covered with a sound-absorbing material. Some high performance cars have openings in the hood to allow the engine to "breathe" easier. "Hood scoops" are used to channel outside air directly to the air filter, which gives improved performance and efficiency.
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Mirrors
The driver's side mirror is connected to the driver's side of the car's body. This mirror is a very important device, not for adjusting your make-up. It enables you, with a slight glance of the eye, to see places that you can't otherwise see without taking your eyes off the road. The mirror is adjusted by the driver to suit the necessary visibility position (position of the head). Sometimes the mirror must be manually adjusted outside the car.
The mirror is also often controlled from the inside of car by a series of cables. The cables are connected to a "joystick or toggle" that allows you to tilt the mirror manually, or to an electrical motor that allows you to tilt the mirror by pushing a button.
The rear view mirror is a wide rectangular mirror that you (the driver) use to view anything behind the car. You don't have to take your eyes off the road to turn your head around. On most cars, the rear view mirror has a "day/night" selection switch that tilts the mirror inside its glass housing without tilting the exterior glass housing itself. The switch tilts the mirror upward, about five degrees, to divert the majority of the light striking the mirror up on to the headliner of the car. The light that you see when the mirror is on the "night" setting is actually bouncing off the glass housing (a good reason to keep it clean). The percentage of light reflected into your eyes in the night position, is very small compared to the amount that would normally be reflected into your eyes in its normal position.
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Radiator Grille
The radiator grille is the part of the body shell on the front of your car that covers the area where the air enters. The radiator grille can also be part of the bumper on some cars. The radiator is connected to the shroud for the radiator. The shroud directs the air that comes in through the radiator grille to the radiator only. This prevents the air from escaping around the radiator and failing to cool the engine. On newer cars, the radiator grille has been lowered to take advantage of lower hood lines, brought about by an effort to increase fuel efficiency. Older cars had massive grilles, whereas the cars now produced have smaller more aerodynamic grilles.
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Rust Prevention
Rust is very bad for your car. It will also depreciate the value of your car more than any other problem. It is the most difficult and expensive problem to fix. The best way to protect your car against rust is to keep the body clean and check it regularly. If you see a light brown stain, don't ignore it, have it fixed before it gets worse. Although most rust problems can be repaired, if it involves chrome parts, you will need to replace them.
The major cause of rust is salt on the roads. The salt carries moisture into every nook and cranny of your car. Rising temperatures bring on salt-caused oxidation. This makes the salt already in your car worse in the spring. Heat in your garage will also bring out the worst in the salt. Acid rain is also bad for your car's body; it ruins the paint that protects the metal of the body.
Undercoating is not rustproofing. Its job is to deaden sound. If any salt or moisture gets into the undercoating, it aids in the rusting process. Therefore, in order to prevent rust you should:
Keep your car clean and well waxed.
Rinse the underside with water if you live in a salty area.
Keep your wheel wells clean and free from material that holds moisture, such as dirt or leaves.
Make sure that all drain holes in the frame, floor and bottoms of doors are clear.
After you wash your car, open the doors to let the water drain out.
Rust proofing is a treatment of waxy paste sprayed inside the body panels by an "after market" specialist. The specialist drills holes in hidden areas, sprays in the paste, and plugs the holes. Another type of rustproofing is a clear silicon-based spray that is applied to your paint to protect it from chemicals and pollution. Modern cars come with good built-in corrosion protection and warranties against corrosion. You might wind up sealing in the corrosives you are trying to protect against. Also, many car manufacturers void your corrosion warranty if you have your car rustproofed. The best course is to take the rust preventative measures listed above.
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Seats
There are basically two types of seats; bench seats or bucket seats.
A bucket seat is a low, separate seat for one person. Although we think of them as relatively new, it is interesting to note that in 1905 Henry Ford's first model A had bucket seats. Bench seats are a continuous cushion and backrest across the width of the car (although some vans might have them running along the length of the van). Bucket seats are single units with a separation between the left and right seats.
Usually vinyl leather and fabric are used for upholstery. "Flatsprings" are used for comfort. A flatspring is a piece of wire that is bent into a zigzag pattern. Both ends of the wire are attached to the seat frame, with additional lengths added every six inches. Foam padding is used to cover the flatsprings.
The front seats ride on rails that are bolted to the floor. This arrangement allows the seats to move backwards and forwards to suit the driver or passenger. The seat adjustment lever is attached to a latch that fits into teeth along the rail. Moving the lever releases the seat, and allows the seat to move. At any point of the seat's movement, releasing the lever engages the latch with one of the teeth. Usually there is also a pull-spring; this draws the seat forward when the latch is released.
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Seat Belts and Air Bags
The first federal study of automobile air bags in actual traffic accidents has found that air bags used in conjunction with seat belts are far more effective than seat belts alone. Air bags reduce the risk of death in head-on collisions by 26% and in all serious accidents by 13%.
Contrasting earlier findings that did not involve actual road conditions, the study showed that air bags protected occupants in ways that seat belts alone, did not. The air bag spread out the violent impact of a crash and kept occupants from smashing against the steering wheel, dashboard or windshield. Therefore, having an air bag and wearing an effective seat belt offers the best protection of all. Not only are you protected from frontal crashes by the air bag -- you are also protected by the seat belt in all other types of crashes.
Studies show that 60% of the people killed or injured in automobile accidents would have been saved from serious injury by wearing seat belts. With an "effective" safety belt (one that is worn and operating correctly), your body will stop, in a crash, before you have a chance to hit or go through the windshield and parts of your car. Seat belts are especially important in small cars, because your chances of being killed or badly hurt in a collision with a big car is eight times greater. Wearing your belt will greatly improve your chances of survival.
Air bags are only useful in frontal crashes, so it is not a good idea to skip your seat belt because you have an air bag. Air bags provide very effective protection in frontal crashes, inflating instantly to protect the driver or passenger that has a air bag. They spread the impact of the crash over the individual's head and chest and protect fragile body parts from the car's hard surfaces.
The main concern of car safety research in the last few years has been the development of passive safety design features, where the aim is to improve the "crash-worthiness" of vehicles. The fundamental aim of good passive safety design is to ensure that only tolerable loads are applied to a car occupant's body during a crash. This is done first by restraining the occupant within the passenger compartment by means of a seat belt or other device, so that chances of making contact with the interior parts of the car are reduced. Secondly, when contacts cannot be avoided, the structures which are likely to be hit by the occupants must be designed to collapse and cushion them.
It is important for the designers to have some knowledge of the forces that the human body can withstand, but as yet this branch of biomechanics has not been fully researched. Work is done at low impact energy levels using volunteers, but for high speed crashes it is necessary to use dummies. However, the relationship between dummy performance and that of a real person in a crash is complex, and it may be that these differences are very considerable. To reduce this problem, some work is currently being done using human cadavers.
In spite of the difficulties in this area, many basic improvements have been introduced into cars in recent years. These include anti-burst door latches, safety glass, energy-absorbing steering wheels and columns, head restraints, and various seat belt and air bag systems. Furthermore, the benefits of the three-point seat belts have been firmly established: Over 50% of fatal and serious injuries to car occupants would be avoided if all occupants wore their seat belts. All states now have a law that both passengers and driver must have seat belts buckled while in motion.
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Springs
Springs all have one thing in common; they are made of specially formulated steel which is tempered to prevent it from loosing the shape it is bent into when "sprung." For this reason, a spring will compress or extend and then return almost entirely to it original shape. There are two kinds of springs, leaf springs and coil springs.
Springs have life spans that are determined by the number of cycles they can withstand over a certain period of time. Occasionally a spring will break on a car while it is being driven. This doesn't usually lead to a collision, but if a spring breaks while you are driving , the car will suddenly lurch downward. The bottom of the car might be damaged, or you might lose your muffler!
Leaf springs are made of individual springs, or plates. If you break one plate of your leaf-spring, it won't be noticeable, but your car might begin to lean to one side or the other. Coil springs, if they break, will suddenly drop the front or rear end of your car and impair driving under the normal conditions of full suspension travel.
Usually the springs surround the shock absorbers, because space can be saved by putting the shock absorber inside the spring. The spring on a MacPherson strut suspension rotates along with the strut body itself; it pivots on a bearing mounted to the wheel well. Some springs have adjustment dials mounted between them and their mounting points. This allows the mechanic to increase the spring tension and the ride height, you desire. This type of spring allows the raising and lowering of suspension system's heigt.
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Window Winding Mechanisms
There are two types of window winding mechanisms; hand cranked (manual) and power.
Hand cranks work two ways. With "window winders," the crank turns a "sector gear" that pivots a pair of arms. The arms raise the "window carrier" and the glass. Some cars have fixed glazing in the rear doors so that the window cannot go up or down. The other type of window crank is a tape mechanism. It winds up a ladder-like tape made of plastic links. The plastic links are wound on to or off a spool to raise or lower the glass. The tape mechanism was introduced in 1980 GM cars. It saves weight and space. Its parts will not corrode when rainwater gets into the door, and it needs no lubrication.
Power windows use a small electric motor inside the door. The motor turns the crank that raises the window. Power windows are usually operated by pressing a "rocker switch" that activates a motor, moving the window up or down.
Door and vent windows are made of laminated "safety" plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic even when shattered.
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Windshield
Up until 1935 many cars had hinged windshields that could be folded on the hood of the car or opened up. Today, most windshields are stationary. They are fixed in place with a weather-strip made of rubber. The strip has a groove on the inside and a groove on the outside. The inside groove holds the glass; the outside groove holds the metal rim of the windshield opening in place. The glass "floats" in a plastic sealant that is spread out between the edge of the glass and the frame of the windshield.
Windshields are made of laminated safety plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic to eliminate glass from flying around the interior and injuring someone.
Safety glass for windscreens was one of the first passive safety devices introduced into cars in the 1930s, but its use remains a controversial question. North America and Scandinavia favor a laminated glass, which consists of two sheets of annealed glass, separated by a layer of transparent plastic. The rest of Europe and Japan favor toughened glass because it is cheaper. This type is a single sheet of glass which is heat strengthened, and which on impact fractures into small cubic fragments without very sharp edges. In recent years, laminated glass has been improved by changes in the properties of the plastic interlayer. Research has demonstrated that this new laminated glass is about 4 times safer than toughened glass, but because it is more expensive, controversy continues as to whether or not toughened glass windscreens should be banned by legislative action and replaced by laminated glass.
Recent developments have combined the benefits of both laminated and toughened material in that a laminated construction is used, but the sheet next to the inside of the car is made of toughened glass.
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