A suction cup known as a sucker, is a device or object that uses the negative fluid pressure of air or water to adhere to nonporous surfaces, creating a partial vacuum. Suction cups are peripherial traits of some animals such as octopuses and squids, have been reproduced artificially for numerous purposes; the working face of the suction cup has a curved surface. When the center of the suction cup is pressed against a flat, non-porous surface, the volume of the space between the suction cup and the flat surface is reduced, which causes the air or water between the cup and the surface to be expelled past the rim of the circular cup; the cavity which develops between the cup and the flat surface has little to no air or water in it because most of the fluid has been forced out of the inside of the cup, causing a lack of pressure. The pressure difference between the atmosphere on the outside of the cup and the low-pressure cavity on the inside of the cup keeps the cup adhered to the surface; when the user ceases to apply physical pressure to the outside of the cup, the elastic substance of which the cup is made tends to resume its original, curved shape.
The length of time for which the suction effect can be maintained depends on how long it takes for air or water to leak back into the cavity between the cup and the surface, equalizing the pressure with the surrounding atmosphere. This depends on the properties of the cup's rim; the force required to detach an ideal suction cup by pulling it directly away from the surface is given by the formula: F = A P where: F is the force, A is the area of the surface covered by the cup, P is the pressure outside the cup This is derived from the definition of pressure, which is: P = F / A For example, a suction cup of radius 2.0 cm has an area of π 2 = 0.0013 square meters. Using the force formula, the result is F = = about 130 newtons; the above formula relies on several assumptions: The outer diameter of the cup does not change when the cup is pulled. No air leaks into the gap between the cup and the surface; the pulling force is applied perpendicular to the surface so that the cup does not slide sideways or peel off.
Artificial suction cups are believed to have first been used in the third century, B. C. and were made out of gourds. They were used to suction "bad blood" from internal organs to the surface. Hippocrates is believed to have invented this procedure; the first modern suction cup patents were issued by the United States Patent and Trademark Office during the 1860s. TC Roche was awarded U. S. Patent No. 52,748 in 1866 for a "Photographic Developer Dipping Stick". In 1868, Orwell Needham patented a more refined suction cup design, U. S. Patent No. 82,629, calling his invention an "Atmospheric Knob" purposed for general use as a handle and drawer opening means. Suction cups have a number of commercial and industrial applications: To affix objects to nonporous vertical surfaces such as refrigerator doors and tiled walls, mooring ships To move large smooth objects such as panes of glass, automobile windscreens and raised floor tiles In toys such as Nerf darts In toilet plungers By urban climbers, to scale buildings with smooth exterior surfacesOn May 25, 1981, Dan Goodwin, a.k.a.
SpiderDan, scaled Sears Tower, the former world's tallest building, with a pair of suction cups. He went on to scale the Renaissance Center in Dallas, the Bonaventure Hotel in Los Angeles, the World Trade Center in New York City, Parque Central Tower in Caracas, the Nippon TV station in Tokyo, the Millennium Tower in San Francisco. Horror vacui Magdeburg hemispheres Self-sealing suction cup
Crimping is joining two or more pieces of metal or other ductile material by deforming one or both of them to hold the other. The bend or deformity is called the crimp; the metals are joined together via a special connector. Stripped wire is inserted through the sized opening of the connector, a crimper is used to squeeze the opening against the wire. Depending on the type of connector used, it may be attached to a metal plate by a separate screw or bolt or it could be screwed on using the connector itself to make the attachment like an F connector. Crimping is most extensively used in metalworking. Crimping is used to fix bullets in their cartridge cases, for rapid but lasting electrical connections, securing lids on metal food cans, many other applications; because it can be a cold-working technique, crimping can be used to form a strong bond between the workpiece and a non-metallic component. When joining segments of tubular sheet metal pipe, such as for smoke pipes for wood stoves, downspouts for rain gutters, or for installation of ventilation ducting, one end of a tube is treated with a crimping tool to make a slip joint into the next section of duct.
The joint will be adequate for conveying low pressure fluids. Crimp joints may be arranged to prevent accumulation of dirt. In jewelry manufacture, crimp beads, or crimp tubes, are used to make secure joints in fine wire, such as used in clasps or tie loops. A crimped lead seal is attached to secure wires used to secure fasteners in aircraft, or to provide visual evidence of tampering when securing a utility meter or as a seal on cargo containers. Pliers
Adhesive tape refers to any one of a variety of combinations of backing materials coated with an adhesive. Different backing materials and adhesives can be used depending on the intended use. Pressure-sensitive adhesive, a key component of some adhesive tapes, was first developed in 1845 by Dr. Horace Day, a surgeon. In 1901, the German Oscar Troplowitz invented an adhesive patch called Leukoplast for the German company Beiersdorf AG. In 1936, German company Beiersdorf AG invented. Pressure-sensitive tape, PSA tape, self-stick tape or sticky tape consists of a pressure-sensitive adhesive coated onto a backing material such as paper, plastic film, cloth, or metal foil, it is solvent for activation and adheres with light pressure. These tapes require a release agent on their backing or a release liner to cover the adhesive. Sometimes, the term "adhesive tape" is used for these tapes. Many pressure-sensitive adhesive tapes exhibit triboluminescence, observable in a dark room, when peeled off a dispenser roll or other surface.
The adhesiveness of the tape does depend not only on the type of the tape but on its macroscopic shape. Tapes with sharp corners start to detach at pointed corners; the adhesive strength can be sufficiently improved by cutting the edges as shown in the film Water activated tape, gummed paper tape or gummed tape is starch- or sometimes animal glue-based adhesive on a kraft paper backing which becomes sticky when moistened. A specific type of gummed tape is called reinforced gummed tape; the backing of this reinforced tape consists of two layers of paper with a cross-pattern of fiberglass filaments laminated between. The laminating adhesive had been asphalt but now is more a hot-melt atactic polypropylene. Gummed tapes are described in ASTM D5749-01 Standard Specification for Reinforced and Plain gummed Tape for Sealing and Securing. Water-activated tape is used for sealing boxes. Before closing corrugated fiberboard boxes, the tape is activated by water; the tape is 3 inches wide. Heat activated tape is tack-free until it is activated by a heat source.
It is sometimes used for example, a tear strip tape for cigarette packs. Conversely, thermal release tape, such as REVALPHA by Nitto Denko, loses its tack and releases when heated to a certain temperature; this type of tape is used in the semiconductor industry. Drywall tape is cloth, or mesh, sometimes with a gummed or pressure-sensitive adhesive, it is used to make the joints between sheets of drywall materials. Chemistry of adhesive tapes Tape dispenser Masking tape Sellotape Duct tape Electrical tape Sticky mat Nature – Tape X-rays FIPAGO – International Federation of Manufacturers of Gummed Paper
In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass i.e. to accelerate. Force can be described intuitively as a push or a pull. A force has both direction, making it a vector quantity, it is measured in the SI unit of newtons and represented by the symbol F. The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, is inversely proportional to the mass of the object. Concepts related to force include: thrust. In an extended body, each part applies forces on the adjacent parts; such internal mechanical stresses cause no acceleration of that body as the forces balance one another. Pressure, the distribution of many small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate.
Stress causes deformation of solid materials, or flow in fluids. Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, a inadequate view of the nature of natural motion. A fundamental error was the belief that a force is required to maintain motion at a constant velocity. Most of the previous misunderstandings about motion and force were corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved for nearly three hundred years. By the early 20th century, Einstein developed a theory of relativity that predicted the action of forces on objects with increasing momenta near the speed of light, provided insight into the forces produced by gravitation and inertia.
With modern insights into quantum mechanics and technology that can accelerate particles close to the speed of light, particle physics has devised a Standard Model to describe forces between particles smaller than atoms. The Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic and gravitational. High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction. Since antiquity the concept of force has been recognized as integral to the functioning of each of the simple machines; the mechanical advantage given by a simple machine allowed for less force to be used in exchange for that force acting over a greater distance for the same amount of work. Analysis of the characteristics of forces culminated in the work of Archimedes, famous for formulating a treatment of buoyant forces inherent in fluids.
Aristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology. In Aristotle's view, the terrestrial sphere contained four elements that come to rest at different "natural places" therein. Aristotle believed that motionless objects on Earth, those composed of the elements earth and water, to be in their natural place on the ground and that they will stay that way if left alone, he distinguished between the innate tendency of objects to find their "natural place", which led to "natural motion", unnatural or forced motion, which required continued application of a force. This theory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows; the place where the archer moves the projectile was at the start of the flight, while the projectile sailed through the air, no discernible efficient cause acts on it.
Aristotle was aware of this problem and proposed that the air displaced through the projectile's path carries the projectile to its target. This explanation demands a continuum like air for change of place in general. Aristotelian physics began facing criticism in medieval science, first by John Philoponus in the 6th century; the shortcomings of Aristotelian physics would not be corrected until the 17th century work of Galileo Galilei, influenced by the late medieval idea that objects in forced motion carried an innate force of impetus. Galileo constructed an experiment in which stones and cannonballs were both rolled down an incline to disprove the Aristotelian theory of motion, he showed that the bodies were accelerated by gravity to an extent, independent of their mass and argued that objects retain their velocity unless acted on by a force, for example friction. Sir Isaac Newton described the motion of all objects using the concepts of inertia and force, in doing so he found they obey certain conservation laws.
In 1687, Newton published his thesis Philosophiæ Naturalis Principia Mathematica. In this work Newton set out three laws of motion that to this day are t
Anchor bolts are used to connect structural and non-structural elements to the concrete. The connection is made by an assembling of different components such as: anchor bolts, steel plates, stiffeners. Anchor bolts transfer different types of load: shear forces. A connection between structural elements can be represented by steel column attached to reinforced concrete foundation. Whereas, a common case of non-structural element attached to a structural one is represented by the connection between a facade system and a reinforced concrete wall; the simplest – and strongest – form of anchor bolt is cast-in-place, with its embedded end consisting of a standard hexagonal head bolt and washer, 90-bend, or some sort of forged or welded flange. The last are used in concrete-steel composite structures as shear connectors. Other uses include anchoring machines to poured concrete floors and buildings to their concrete foundations. Various disposable aids of plastic, are produced to secure and align cast-in-place anchors prior to concrete placement.
Moreover their position must be coordinated with the reinforcement layout. Different types of cast-in-place anchors might be distinguished: Lifting inserts: used for lifting operations of plain or prestressed RC beams; the insert can be a threaded rod. See Bolt. Anchor channels: used in precast concrete connections; the channel can be a hot-rolled or a cold-formed steel shape in which a T-shape screw is placed in order to transfer the load to the base material. Headed Stud: consist of a steel plate with headed studs welded on. Threaded sleeves: consist of a tube with an internal thread, anchored back into the concrete. For all the type of the cast-in-place anchors, the load-transfer mechanisms is the mechanical interlock, i.e. the embedded part of the anchors in concrete transfers an the applied load via bearing pressure at the contact zone. At failure conditions, the level of bearing pressure can be higher than 10 times the concrete compressive strength, if a pure tension force is transferred.
Cast-in-place type anchors are utilized in masonry applications, placed in wet mortar joints during the laying of brick and cast blocks. Post-installed anchors can be installed in any position of hardened concrete after a drilling operation. A distinction is made according to their principle of operation; the force-transfer mechanism is based on friction mechanical interlock guaranteed by expansion forces. They can be furtherly divided into two categories: torque controlled: the anchor is inserted into the hole and secured by applying a specified torque to the bolt head or nut with a torque wrench. A particular sub-category of this anchor is called wedge type; as shown in the figure, tightening the bolt results in a wedge being driven up against a sleeve, which expands it and causes it to compress against the material it is being fastened to.displacement controlled: consist of an expansion sleeve and a conical expansion plug, whereby the sleeve is internally threaded to accept a threaded element.
The force-transfer mechanism is based on mechanical interlock. A special drilling operation allows to create a contact surface between the anchor head and the hole's wall where bearing stresses are exchanged; the force-transfer mechanism is based on bond stresses provided by binding organic materials. Both Ribbed bars and threaded rods can be used and a change of the local bond mechanism can be appreciated experimentally. In ribbed bars the resistance is prevalently due to shear behavior of concrete between the ribs whereas for threaded rods friction prevails.. Bonded anchors are referred as adhesive anchors; the anchoring material is an adhesive consisting of epoxy, polyester, or vinylester resins. The performance of this anchor's types in terms of'load-bearing capacity' under tension loads, is related to the cleaning condition of the hole. Experimental results showed that the reduction of the capacity is up to 60%; the same applies for moisture condition of concrete, for wet concrete the reduction is of 20% using polyester resin.
Other issues are represented by high temperature creep response. The force-transfer mechanism of the screw anchor is based on concentrated pressure exchange between the screw and concrete through the pitches. Tapcon screws are a popular anchor. Larger diameter screws are referred to as LDT's; this type of fastener requires a pre-drilled hole—using a Tapcon drillbit—and are screwed into the hole using a standard hex or phillips bit. These screws are blue, white, or stainless, they are available in versions for marine or high stress applications. Their force-transfer mechanism is similar to mechanical expansion anchors. A torque moment is applied to a screw, inserted in a plastic sleeve; as the torque is applied the plastic expands the sleeve against the sides of the hole acting as expansion force. They act transferring the forces via mechanical interlock; this fastening technology is used in steel-to-steel connection, for instance to connect cold-formed profiles. A screw is inserted into the base material via a gas actuated gas gun.
The driving energy is provided by firing a combustible propellant in powder form. The fastener's insertion provokes the plastic deformation of the base material which accommodates the fastener's head where the force transfer takes place. Anchors can fail in different way when loaded in tension: Steel failure: the weak part of the connection is represented by the rod; the failure corresponds to the tensile break-out of steel as in
A hinge is a mechanical bearing that connects two solid objects allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation: all other translations or rotations being prevented, thus a hinge has one degree of freedom. Hinges may be made of moving components. In biology, many joints function as hinges like the elbow joint. There are many types of door hinges; the main types include: Spring hinge a spring-loaded hinge made to provide assistance in the closing or the opening of the hinge leaves. A spring is a component of a hinge, that applies force to secure a hinge closed or keep a hinge opened. Barrel hinge a sectional barrel secured by a pivot. A barrel is a component of a hinge, that has a hollow cylinder shaped section where the rotational bearing force is applied to the pivot, may have a screw shaped section for fastening and/or driving the pivot. Pivot hinges which pivot in the top of the door frame.
Referred to as a double-acting floor hinge. This type is found in ancient dry stone buildings and in old wooden buildings; these are called haar-hung doors. They are a low cost alternative for use with light weight doors. Butt/Mortise hinges in threes or fours, which are inset into the door and frame. Most residential hinges found in the U. S. are made of steel, although mortise hinges for exterior doors are made of brass or stainless steel to prevent corrosion. Case hinges Case hinges are similar to a butt hinge however more of a decorative nature most used in suitcases and the like. Continuous hinges, or piano hinges This type of hinge is known as a piano hinge, it runs the entire length of panel, or box. Continuous hinges are manufactured without holes; these hinges come in various thicknesses, pin diameters, knuckle lengths. Concealed hinges Used for furniture doors, they are made of two parts: One part is the hinge cup and the arm, the other part is the mounting plate. Called "cup hinge", or "Euro hinge", as they were developed in Europe and use metric installation standards.
Most such concealed hinges offer the advantage of full in situ adjustability for standoff distance from the cabinet face as well as pitch and roll by means of two screws on each hinge. Butterfly hinges, or Parliament Hinges These were known as dovetail hinges from the 17th century onwards and can be found on old desks and cabinets from about 1670 until the 18th century; the form of these hinges varied between manufacturers, their size ranged from the large for heavy doors to the tiniest decorative hinge for use on jewellery boxes. Many hinges of this type were exported to America to support the home trade's limited supply, they are still found to be both cheap and decorative on small items. Flag hinges A flag hinge can be taken apart with a fixed pin on one leaf. Flag hinges can swivel a full 360 degrees around the pin. Flag hinges are manufactured as a left hand configuration. Strap used on many kinds of interior and exterior doors and cabinets. H used on flush-mounted doors. Small H hinges tend to be used for cabinets hinges, while larger hinges are for passage doors or closet doors.
HL hinges Large HL hinges were common for passage doors, room doors and closet doors in the 17th, 18th and 19th centuries. On taller doors H hinges were used in the middle along with the HL hinges. Other types include: Counterflap hinge Flush hinge Coach hinge Rising Butt hinge Double action spring hinge Double action non-spring Tee hinge Friction hinge Security hinge Cranked hinge or stormproof hinge Lift-off hinge Self closing hinge Since at least medieval times there have been hinges to draw bridges for defensive purposes for fortified buildings. Hinges are used in contemporary architecture where building settlement can be expected over the life of the building. For example, the Dakin Building in Brisbane, was designed with its entrance ramp on a large hinge to allow settlement of the building built on piles over bay mud; this device was effective until October 2006, when it was replaced due to damage and excessive ramp slope. Hinges appear in large structures such as elevated railroad viaducts.
These are included to reduce or eliminate the transfer of bending stresses between structural components in an effort to reduce sensitivity to earthquakes. The primary reason for using a hinge, rather than a simpler device such as a slide, is to prevent the separation of adjacent components; when no bending stresses are transmitted across the hinge it is called a zero moment hinge. People have developed a variety of self-actuating, self-locking hinge designs for spacecraft deployable structures such as solar array panels, synthetic aperture radar antennas, radiators, etc. Pin The rod that holds the leaves together, inside the knuckle. Knuckle The hollow—typically circular—portion creating the joint of the hinge through which the pin is set; the knuckles of either leaf alternate and interlock with the pin passing through all of them. Leaf The portions that extend laterally from the knuckle and revolve around the pin. End play Axial movement between the leaves along the axis of the pin; this motion allows the leaves to rotate without binding and is determined by the typical distance between knuckles when both edges of the leaves are aligned.
Gauge Thickness of the leaves. Hinge width Len
A latch or catch is a type of mechanical fastener that joins two objects or surfaces while allowing for their regular separation. A latch engages another piece of hardware on the other mounting surface. Depending upon the type and design of the latch, this engaged bit of hardware may be known as a keeper or strike. A latch is not the same as the locking mechanism of a door or window, although they are found together in the same product. Latches range in complexity from flexible one-piece flat springs of metal or plastic, such as are used to keep blow molded plastic power tool cases closed, to multi-point cammed latches used to keep large doors closed. A single-throw bolt; the bolt can be engaged in its strike plate. The locking mechanism prevents the bolt from being retracted by force. Latchbolt or Latch bolt An common latch type part of a lockset, it is a spring-loaded bolt with an angled edge; when the door is pushed closed, the angled edge of the latchbolt engages with the lip of the strike plate.
Once the door is closed, the bolt automatically extends into the strike plate, holding the door closed. The latchbolt is disengaged when the user turns the door handle, which via the lockset's mechanism, manually retracts the latchbolt, allowing the door to open. Deadlocking latchbolt is an elaboration on the latchbolt which includes a guardbolt to prevent “shimming” or “jimmying” of the latch bolt; when the door is closed, the latchbolt and guardbolt are retracted together, the door closes with the latchbolt entering the strike plate. The strike plate, holds the guardbolt in its depressed position: a mechanism within the lockset holds the latchbolt in the projected position; this arrangement prevents the latchbolt from being depressed through the use of a credit card or some other tool, which would lead to unauthorized entry. Draw Latch is a two part latch where one side has an arm that can clasp to the other half, as it closes the clasp pulls the two parts together. Used on tool boxes, chests and windows.
Doesn't need to be closed to secure both halves. Spring bolt lock: A locking mechanism used with a latchbolt A slam latch uses a spring and is activated by the shutting or slamming of a door. Like all latches, a slam latch; the slam latch derives its name from its ability to slam doors and drawers shut without damaging the latch. A slam latch is rugged and ideal for industrial and construction applications. A cam lock is a type of latch consisting of a cam; the base is where the key or tool is used to rotate the cam, what does the latching. Cams can offset. Found on garage cabinets, file cabinets, tool chests, other locations where privacy and security is needed. A Norfolk latch is a type of latch incorporating a simple thumb-actuated lever and used to hold wooden gates and doors closed. In a Norfolk latch, the handle is fitted to a backplate independently of the thumb piece. Introduced around 1800–1820, Norfolk latches, originating in the English county of the same name, differ from the older Suffolk latch, which lacked a back plate to which the thumbpiece is attached.
A Suffolk latch is a type of latch incorporating a simple thumb-actuated lever and used to hold wooden gates and doors closed. The Suffolk latch originated in the English county of Suffolk in the 16th century and stayed in common use until the 19th century, they have come back into favour on garden gates and sheds. They were common from the 17th century to around 1825, their lack of a back plate made them different from the and neighbouring Norfolk latch. Both the Suffolk latch and Norfolk latch are thought to have been named by architectural draughtsman William Twopenny. Many of these plates found their way into other parts of the world. A crossbar, sometimes called a bolt, is a primitive fastener consisting of a post barring a door. Crossbars were common, simple fasteners consisting of a plank or beam mounted to one side of a door by a set of cleats; the board could be slid past the frame to block the door. Alternatively, the bar can be a separate piece, placed into open cleats or hooks, extending across the frame on both sides.
The effect of this device is the opposite of the crash bar in that its operation is to permit the door to be opened inward rather than outward. On a set of double doors, the same principle needn't extend past the frame; the bar extends into another set of cleats on the other door such as to interfere with the door opening. A cabin hook is a hooked bar; the bar is attached permanently to a ring or staple, fixed with screws or nails to woodwork or a wall at the same level as the eye screw. The eye screw is screwed into the adjacent wall or onto the door itself. Used to hold a cupboard, door or gate open or shut. A cabin hook is used in many situations to hold a door open, like on ships to prevent doors from swinging and banging against other woodwork as the ship moves due to wave action; this usage spread to other domains, where a door was required to be held open or a self-closing device is used to close the door. Many buildings are built with fire-resistant doors to separate different parts of buildings and to allow people to be protected from fire and smoke.
When using a cabin hook in such a situation, one should keep in mind that a fire-resistant door is an expensive and h