Elementary Mechanism: A Textbook for Students of Mechanical EngineeringD. Van Nostrand Company, 1893 - 310 páginas |
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Elementary Mechanism: A Textbook for Students of Mechanical Engineering Arthur Tannatt Woods,Albert W Stahl Sin vista previa disponible - 2016 |
Términos y frases comunes
addendum circle angle angular velocity annular wheel arc of action arc of recess arcs of approach axis base circle belt centre of motion circular arcs clock common normal connected constant velocity ratio construction cycloid cylinder dead points describing circle directional relation distance draw driver driver's teeth ellipse epicycloid equal escape wheel evidently face flanks follower follower's gear generatrix given groove hence hyperboloids hypocycloid inches instant intersection involute system latter least number length line of centres linkwork logarithmic spiral minute move number of axes number of teeth obliquity pair parallel pendulum perpendicular piece pinion pitch diameter pitch line plane point of contact position pulleys rack radial radii radius ratchet-wheel revolution revolutions per minute rolling contact rotation screw shaft shown in Fig sliding contact spiral spur wheel straight line stroke swing-wheel synchronal rotations tangent tion tooth outlines transmit motion turn
Pasajes populares
Página 247 - This train of wheel-work is solely destined to the purpose of communicating the action of the weight to the pendulum in such a manner as to supply the loss of motion from friction and the resistance of the air. But besides this, the clock is required to indicate the hours and minutes by the rotation of two separate hands, and accordingly two other trains of wheel- work are employed for this purpose.
Página 78 - It is the curve described by a point in the circumference of a circle, while the circle itself rolls in a straight line along a plane.
Página 247 - The train just described is generally contained in a frame, consisting of two plates, shown edgewise at fcZ, mn, which are kept parallel and at the proper distance by means of three or four pillars not shown in the diagram. Opposite holes are drilled in these plates, which receive the pivots of the axes or arbors already described. But the axis which carries A and B projects through the plate, and other wheels E and F are fixed to it. Below this axis, and parallel to it, a stout pin or stud is fixed...
Página 119 - T c of the instrument to the radial line AD, placing its extremity D on the pitch circle, as in the figure. In the table headed, Centers for the Flanks of Teeth, look down the column of 3 inch pitch, and opposite to 30 teeth, which is the nearest number to that required, will be found the number 49. The point g indicated on the drawing-board by the position of this number on the scale of equal parts, marked Scale of Centers for the Flanks of Teeth, is the center required, from which the arc mp must...
Página 80 - Thus in wheels gearing together, since the pitch of the teeth of both wheels is necessarily the same, the numbers of teeth are proportional to the diameters of the pitch circles; and the angularvelocity ratio, which is inversely proportional to the diameters of the pitch circles, is inversely proportional to the numbers of teeth in the wheels. In bevel wheels precisely the same formulae apply, but the pitch circles are conventionally taken as the large circles of the frusta.
Página 259 - ... contact as the wheels run upon each other. We will take the case of a wheel of A teeth driving one of B teeth where A is greater than B, and let - = — when reduced to its lowest terms. B b It is evident that the same points of the two pitch circles would be in contact after a revolutions of B or b revolutions of A. Hence the smaller the numbers which express the velocity ratio of the two axes, the more frequently will the contact of the same pair of teeth recur.
Página 1 - Machine is an assemblage of moving parts, interposed between the power and the work, for the purpose of adapting the one to the other. It is not, however, always necessary to trace back the source of power to its origin. For example, a line of shafting, whether itself driven by wind, water, or steam, may properly be considered as the "source of power" in reference to the various drills, lathes, planers, etc., driven by it.
Página 18 - DI ~Ul' 1. The angular velocities of the arms are to each other inversely as the .perpendiculars from their centres of motion upon the line of the link. 2. The angular velocities of the arms are to each other inversely as the segments into which the line of the link cuts the line of centres. 82. Directional Relation.
Página 121 - The curve n mp is also true for an annular wheel of the same radius and number of teeth, n becoming the root and p the point of the teeth. For a rack, the pitch line DE becomes a right line, and DA, EA, perpendiculars to it, at a distance equal to the pitch.
Página 86 - ... the other wheel until the point of contact has reached the line of centers is the angle of approach ; the angle through which it turns from the instant the point of contact leaves the line of centers until the teeth are no longer in contact is the angle of recess. The sum of these two angles forms the angle of action. The arcs of the pitch circles which measure these angles are called the arcs of approach, recess, and action, respectively. In order that one pair of teeth shall be in contact until...