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Hinge
A hinge is a mechanical bearing that connects two solid objects, typically 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, with all other translations or rotations prevented; thus a hinge has one degree of freedom. Hinges may be made of flexible material or moving components. In biology, many joints function as hinges, such as the elbow joint. History Ancient remains of stone, marble, wood, and bronze hinges have been found. Some date back to at least Ancient Egypt, although it is nearly impossible to pinpoint exactly where and when the first hinges were used. In Ancient Rome, hinges were called cardō and gave name to the goddess Cardea and the main street Cardo. This name cardō lives on figuratively today as "the chief thing (on which something turns or depends)" in words such as ''cardinal''. According to the Oxford English Dictionary, the English word ''h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concealed Hinge Jig
A concealed hinge drilling jig is a type of support jig, designed for drilling 3 cm holes to fit concealed hinges into modern wardrobe doors. As many of the complementary tools used in woodworking, it uses an electric hand-drill for its operation, making a Forstner bit to turn. For most ''concealed hinge''s to work properly, a pit hole must be created on the door at the point where it faces the static part of the hinge which is screwed to the inside wall of the wardrobe. To create the pit hole, the jig must be fixed in place by means of the provided clamp, spin the Forstner bit by applying an electric hand-drill to its axle. The hole is drilled by pressing the hand-drill until a satisfactory pit hole is created. The purpose of the grinding (abrasive cutting), drilling jig is to hold a Forstner bit in place, at a 90º angle while drilling 3 cm pit hole. The angle of the tool is critical for the performance of concealed hinges, the jig allows maintaining the 90º angle ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Door Closer
A door closer is a mechanical device that regulates the speed and action of a door’s swing. Manual closers store the force used to open the door in some type of spring and reuse it to close the door. Automatic types use electricity to regulate door swing behavior. Door closers can be linked to a building's fire and security alarm systems. History Early days One of the first references concerning a device to close a door can be found in the writings of Hero of Alexandria who describes his "automata" which controlled the doors of temples, both opening and closing them automatically. Weights and levers have also been used to close doors. Another device for smaller domestic doors used a loop of rope or skein fixed to the door frame, that was twisted, with a piece of wood placed in between the twists to push the door. The opening of the door twists the skein further, when the door is released the rope's torsional force pushes the arm back against the door, thereby closing it. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardea
Cardea or Carda was the ancient Roman goddess of the hinge (Latin ''cardo, cardinis''), Roman doors being hung on pivot hinges. The Augustan poet Ovid conflates her with another archaic goddess named Carna, whose festival was celebrated on the first day of June and for whom he gives the alternative name Cranê or Cranea, a nymph. Ovid's conflation of the goddesses is likely to have been his poetic invention, but it has also been conjectured that ''Carna'' was a contracted form of ''Cardina'', and at minimum Ovid was observing that their traditions were congruent. Cardea and doorways In the Christian polemic of the Church Fathers, Cardea is associated with two otherwise unknown deities who preside over doorways: Forculus, from ''fores'', "door", plural in form because double doors were common on public buildings and elite homes ('' domūs''); and Limentinus, from ''limen, liminis'', "threshold" (compare English " liminal"). St. Augustine mocks the apparent triviality of thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flexure Bearing
A flexure bearing is a category of flexure which is engineered to be compliant in one or more angular degrees of freedom. Flexure bearings are often part of compliant mechanisms. Flexure bearings serve much of the same function as conventional bearings or hinges in applications which require angular compliance. However, flexures require no lubrication and exhibit very low or no friction. Many flexure bearings are made of a single part: two rigid structures joined by a thin "hinge" area. A hinged door can be created by implementing a flexible element between a door and the door frame, such that the flexible element bends allowing the door to pivot open. Flexure bearings have the advantage over most other bearings that they are simple and thus inexpensive. They are also often compact, lightweight, have very low friction, and are easier to repair without specialized equipment. Flexure bearings have the disadvantages that the range of motion is limited, and often very limited for b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mortise And Tenon
A mortise and tenon (occasionally mortice and tenon) is a Woodworking joints, joint that connects two pieces of wood or other material. Woodworking, Woodworkers around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at right angles, though it can be used to connect two work pieces at any angle. Mortise-and tenon-joints are simple, strong, and stable, and can be used in many projects and which give an attractive look. They are either glued or friction-fitted into place. This joint is difficult to make, because of the precise measuring and tight cutting required; as such, modern woodworkers often use machinery specifically designed to cut mortises and matching tenons quickly and easily. Still, many woodworkers cut them by hand in a traditional manner. There are many variations of this type of joint, but its basic structure has two components, the ''mortise'' hole and the ''tenon'' tongue. The tenon, formed on the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardo
A ''cardo'' (: ''cardines'') was a north–south street in Ancient Rome, ancient Roman cities and military castra, camps as an integral component of Urban planning, city planning. The ''cardo maximus'', or most often the ''cardo'', was the main or central north–south-oriented street. Etymology “Cardo” is the Latin word for "hinge". Being the hinge the turning point of the doors, the word ''cardo'' would also be used to designate other “turning points”, like the North Pole of the sky, or the four ''cardinal'' directions (quattuor ''cardines'' orbis terrarum). Also the “the principal line laid down in surveying land was called ''cardo''", which is also applied to the first street of a city: the street around which the city would be structured. Most Roman cities also had a ''Decumanus, decumanus maximus'', an east–west street that served as a secondary main street. Due to varying geography, in some cities the ''decumanus'' is the main street and the ''cardo'' is secon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell (biology), cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple biological organisation, levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including scientific method, observation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draw Bridge
A drawbridge or draw-bridge is a type of moveable bridge typically at the entrance to a castle or tower surrounded by a moat. In some forms of English, including American English, the word ''drawbridge'' commonly refers to all types of moveable bridges, such as bascule bridges, vertical-lift bridges and swing bridges, but this article concerns the narrower historical definition where the bridge is used in a defensive structure. As used in castles or defensive structures, drawbridges provide access across defensive structures when lowered, but can quickly be raised from within to deny entry to an enemy force. Castle drawbridges Middle Ages, Medieval castles were usually defended by a ditch or moat, crossed by a wooden bridge. In early castles, the bridge might be designed to be destroyed or removed in the event of an attack, but drawbridges became very common. A typical arrangement would have the drawbridge immediately outside a gatehouse, consisting of a wooden Deck (bridge), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw-Hill Connect. Webp.274/ref> They are constructed to allow for different degrees and types of movement. Some joints, such as the knee, elbow, and shoulder, are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as suture (joint), sutures between the bones of the skull permit very little movement (only during birth) in order to protect the brain and the sense organs. The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis. Joints are classified both structurally and functionally. Joints play a vital role in the human body, contributing to movement, sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (device)
A spring is a device consisting of an Elasticity (physics), elastic but largely rigid material (typically metal) bent or molded into a form (especially a coil) that can return into shape after being compressed or extended. Springs can Energy storage, store energy when compressed. In everyday use, the term most often refers to coil springs, but there are many different spring designs. Modern springs are typically manufactured from spring steel. An example of a non-metallic spring is the Bow (weapon), bow, made traditionally of flexible Taxus baccata, yew wood, which when Bow draw, drawn stores energy to propel an arrow. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The ''rate'' or ''spring constant'' of a spring is the change in the force it exerts, divided by the cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakin Building
The Dakin Building is an architectural award-winning class A office building on the San Francisco Bay in Brisbane, California. Serving as a corporate headquarters building for several companies of national prominence, it was built from the profits of the Garfield character whose licensed products of the R. Dakin & Company division of Applause Toys soared in sales in the late 1980s. Located on Sierra Point, it became a landmark in the San Francisco Bay Area for its distinctive design and was nicknamed the Luke Skywalker building for its dramatic posture overlooking the bay, in contrast to a neighboring office building with a dark, ominous appearance that was nicknamed the Darth Vader building. Ownership and history The Dakin Building was constructed in 1986 under commission of the R. Dakin & Co., one of the largest manufacturers of plush products (mainly teddy bears) in the United States at that time. Dakin was in a large upswing of sales and profits in the late 1980s fueled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
