| assembly drawing | (n) Adrawing showing how each part of a design is put together. An assembly drawing normally consists of all the parts drawn in their operating positions and a parts list or bill of materials.
(See 561)
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| bearing | (n) A mechanical device designed to transfer radial or axial loads from a shaft while minimizing energy loss due to friction from the rotating shaft. Bearings are usually divided into two general categories: plain and rolling contact.
(See 586)
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| bill of materials | (n) Alisting of parts or materials used in an assembled object. The listing is usually included as part of the working drawing of the full assembly.
(See 561)
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| bolt | (n) A mechanical fastening device with a head on one end of an externally threaded shaft. Anut is placed on the threaded shaft and rotated to clamp the material between the head and nut.
(See 580)
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| CAM | (n) Acronym for computer-aided manufacturing, which is the use of computers to control the production process. Examples are robots for assembly and numerically controlled machine tools. CAM is often combined with CAD to describe the integration of design and manufacturing through the use of a common computer database.
(See 584)
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| cap screw | (n) A mechanical threaded fastener with a head on one end, used to screw into a mating part. Differing from a bolt, a cap screw has a longer thread length and does not use a nut.
(See 580)
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| detail drawing | (n) A dimensioned multiview drawing of a single part, using ANSI standard conventions to describe the part’s shape, size, material, and finish. Detail drawings are suffi-ciently descriptive that the part can be manu-factured using the drawing as the only communications device. Detail drawings are produced from design sketches or extracted from a 3-D computer model.
(See 561)
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| displacement | (n) The linear or angular distance moved by a part or mechanism. In cam design, a displacement diagram is used to chart the linear location of the follower relative to the angular position of the cam.
(See 585)
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| document sketches | (n) A more formal type of freehand sketch used during the refinement stage of the design process. These sketches often contain many of the conventions found in
more formal drawings.
(See 559)
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| double-line drawing | (n) See piping drawing.
(See 591)
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| fastener | (n) A mechanical device that constrains two or more parts. Fasteners can rigidly join parts or can allow certain degrees of freedom. Some fasteners are meant to be disassembled for maintenance (e.g., screws and bolts), while others are considered permanent (e.g., rivets).
(See 573)
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| gear | (n) A toothed wheel device that acts as a mechanical linkage to transmit power and motion between machine parts. Most gears transfer rotary motion from one shaft to another. They change the location and can change both the orientation and speed of the rotary motion. Certain gear types transform rotary motion into linear (reciprocating) motion.
(See 584)
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| key | (n) A fastening device used to attach shafts to transmit power to gears, pulleys, and other mechanical devices. Common keys are plain, gib head, Woodruff, and Pratt & Whitney. The key is placed into a groove cut into the shaft (the keyseat) and one cut into the hub (the key-way), aligning and locking the parts together. Standard keys are specified using the size of the shaft as the determining factor.
(See 581)
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| linkages | (n) Rigid bodies (parts) that transmit linear or rotational force. Linkages are multiple links that are combined through joints. Constraints applied to the joints define the movement of the individual links. Common types of linkages include rocker arm, crank, lever, and four-bar.
(See 585)
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| links | (n) In a kinematic model, the geometric form representing a unique part of a mechanism. Links are related to each other through joints, which define how they can orient relative to each other.
(See 585)
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| machine | (n) Acombination of interrelated parts used for applying, storing, or transforming energy to do work. Machines consist of one or more assemblies, which are analyzed using techniques such as kinematics and dynamics.
(See 583)
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| machine screw | (n) A mechanical fastening device with a slotted head on one end and threads on the other. The threaded end can screw into either a mating part or a nut. A machine screw is similar to a slotted head cap screw but is normally smaller.
(See 580)
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| mechanism | (n) A mechanical system made of rigid structures, such as shafts, housings, and pillow blocks, and connected by various linkages, such as gears, cams, and cranks. Amechanism is activated by applying a load or force at one or more points in the mechanism.
(See 583)
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| outline assembly | (n) A general graphic description of the exterior shape of an assembly. Outline assemblies are used for parts catalogs and installation manuals or for production when the assembly is simple enough to be visualized without the use of other drawing techniques, such as sectioning. Hidden lines are omitted except for clarity.
(See 561)
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| pin | (n) A mechanical fastener, typically cylindrical in shape, used to keep parts in position or to prevent slippage after assembly. Some of the more common types of pins are dowel, straight, tapered, groove, spring, and cotter.
(See 581)
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| pinion | (n) The smaller of two gears in a meshed pair of gears. The larger of the two gears is simply called the gear. Agear and pinion pair is used to change the speed of shaft rotation, with the pinion shaft rotating at a higher rate than the gear shaft.
(See 584)
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| piping drawing | (n) Aspecialized drawing used in the design and maintenance of piping systems. The piping systems are shown in an orthographic plan view or in a pictorial view such as isometric. The drawing can be done as a single-line drawing in which the components are represented as a single line or as a doubleline drawing for a more realistic spatial layout of the components. Specialized graphic symbols are used to represent the pipes, fittings, and valves used in the system.
(See 588)
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| reprographics | (n) The process of storing, retrieving, and copying engineering drawings. Often, specialized service bureaus are used to provide these services to small firms.
(See 594)
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| revision block | (n) An area located next to the title block, listing the version, or revision, of the drawing depicted.
(See 570)
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| rivet | (n) Apermanent mechanical fastener, consisting of a smooth metal shaft with a head. Rivets are placed in the part and held in place by spreading the tip protruding through the material.
(See 581)
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| scanner | (n) A computer input device used to capture information on paper and translate the information into a raster (bitmapped) computer image. Scanners can be used to convert a drawing created with traditional tools to a CAD drawing, to convert and enhance photographs in desktop publishing, or to input text information into the computer.
(See 596)
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| section assembly | (n) An assembly drawing that provides a general graphic description of the interior shape of an assembly by passing a cutting plane through the assembly. The section assembly is usually a multiview drawing of all the assembled parts, with one view in full section. Other types of sections can also be used, such as broken-out and half sections.
(See 563)
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| set screw | (n) A mechanical threaded fastener, with or without a head, used to prevent rotation or movement between parts, such as a shaft and a collar. Set screws have special types of points for different applications.
(See 581)
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| spring | (n) A mechanical device, often in the form of a helix, that expands or contracts due to pressure or force. Springs are classified as compression, tension, extension, flat, and constant force. A spring is further classified by the material, gage, spring index, direction of the helix, and type of ends.
(See 583)
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| stud | (n) A mechanical fastening device that consists of a cylindrical rod threaded on one or both ends and that screws into a mating part. A nut may be used on one end.
(See 580)
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| subassembly | (n) A logical grouping of parts that are only part of the total assembly. Often, a subassembly is a working mechanism in and of itself, but it works in concert with other parts to form the complete assembly.
(See 561)
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| virtual models | (n) A computer-based model analogous to a real or proposed object. Virtual models are endowed with the qualities of a real object, allowing the models to be used in evaluating a proposed design. Virtual models are useful for quickly performing multiple tests that could be destructive to physical models.
(See 589)
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| washer | (n) A round piece of material with a hole in the center, used with mechanical fasteners to improve the assembling surface, distribute load, and assist in locking nuts. Washers are specified by giving the inside diameter, outside diameter, thickness, type, and name.
(See 581)
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| working assembly drawing | (n) A drawing that combines the detail drawing with the assembly drawing. For relatively simple assemblies using some standard parts, it is possible to combine the detail drawing with the assembly drawing by using a section view.
(See 572)
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| working drawings | (n) The complete set of standardized drawings that specify the manufacture and assembly of a design. Depending on the complexity of the design, working drawings may be on more than one sheet and may contain written instructions, called specifications. Working drawings are often synonymous with the “blueprints” of a design.
(See 559)
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2002 McGraw-Hill Higher Education