Principles of Mechanism: Designed for the Use of Students in the Universities and for Engineering Students GenerallyJ.E. Parker, 1841 - 446 páginas |
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Página iv
... move they all receive a motion , the relation of which to that of the first is governed by the nature of the connexion . The work which the machine has to do will require that the pieces appropriated to this work shall move with respect ...
... move they all receive a motion , the relation of which to that of the first is governed by the nature of the connexion . The work which the machine has to do will require that the pieces appropriated to this work shall move with respect ...
Página v
... move according to the law required by the economy of the power , the last shall necessarily receive the motion which will enable them to do the work . There are , of course , many essential considerations of force and arrangement which ...
... move according to the law required by the economy of the power , the last shall necessarily receive the motion which will enable them to do the work . There are , of course , many essential considerations of force and arrangement which ...
Página 1
... moving power , and an object subjected to the operation , which may be termed the work to be done . Machines , in fact , are interposed between the power and the work , for the purpose of adapting the one to the other . 2. As an example ...
... moving power , and an object subjected to the operation , which may be termed the work to be done . Machines , in fact , are interposed between the power and the work , for the purpose of adapting the one to the other . 2. As an example ...
Página 2
... moving power , and ending with the grindstone , which in like manner is peculiar and adapted to the work . But this is , in fact , the description of every machine . There is always one or more ... move according to the 2 INTRODUCTION .
... moving power , and ending with the grindstone , which in like manner is peculiar and adapted to the work . But this is , in fact , the description of every machine . There is always one or more ... move according to the 2 INTRODUCTION .
Página 3
... moves ac- cording to a given law , the others must move according to certain other given laws , this branch of the subject may be reduced to geometrical principles alone : whereas by considering mechanism as usual , as a modifier of ...
... moves ac- cording to a given law , the others must move according to certain other given laws , this branch of the subject may be reduced to geometrical principles alone : whereas by considering mechanism as usual , as a modifier of ...
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Principles of Mechanism: Designed for the Use of Students in the ... Robert Willis Visualização integral - 1841 |
Palavras e frases frequentes
addendum angle angular velocity ratio arc of action arrangement axes axis center of motion circumference clock cogs combination cone conical surface connexion constant contrivance corresponding crank cylinder describing circle detent diameter distance edge ellipse employed epicyclic train epicycloid equal equation example excentric extremity fixed fraction frustum geer given groove hyperboloid hypocycloid involute jointed L₁ last wheel line of centers link-work logarithmic spiral machine manner mechanism move number of teeth obtained opposite direction oscillation pair parallel pass path perpendicular piece pinion pitch circle pitch line plane point of contact position produce pully rack radial radii radius ratchet-wheel reciprocating respectively revolution revolve right line rods roller rotation round shew shewn side sliding slit space spur-wheel supposed surface synchronal rotations tangent termed tion toothed wheel values versin wheel-work
Passagens conhecidas
Página iv - At present, questions of this kind can only be solved by that species of intuition which long familiarity with a subject usually confers upon experienced persons, but which they are totally unable to communicate to others. When the mind of a mechanician is occupied with the contrivance of a machine, he must wait until, in the midst of his meditations, some happy combination presents itself to his mind which may answer his purpose.
Página 269 - ... point c of the curve will be moved to in, and thus the pin will be placed in its required position, and so for every other pair of positions.
Página 134 - ... of an inch in 3 inch pitch by always taking the nearest number in the manner directed, and a proportionably smaller error in smaller pitches. But to ensure this, the selected numbers should be so taken, that their respective forms shall lie between the extremes at equal distances. Now it appears that the variation of form is much greater among the teeth of small numbers than among the larger ones, and that in fact COUPLING OF HORIZONTAL AXLES.
Página 212 - 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 vii - Kinematics,) ought to include all that can be said with respect to motion in its different kinds, independently of the forces by which it is produced. It should treat in the first place of spaces passed over, and of times employed in different motions, and of the determination of velocities according to the different relations which may exist between those spaces and times.
Página 132 - Fig. 112 represents the Odontograph exactly half the size of the original ; but as it is merely formed out of a sheet of card-paper, this figure will enable any one to make it for use. The side N TM which corresponds to the line QT q in fig.
Página 133 - The number 21 obtained from the lower table, will indicate the position f of the required center upon the lower scale. In using the instrument, it is only necessary to recollect, that the scale employed and the point m always lie on the two opposite sides of the radial line to which the instrument is applied. The curve...
Página 134 - ... the numbers in the two following series are so arranged that the curves corresponding to them possess this required property. For the outer side of the tooth, 12, 14, 17, 21, 26, 34, 47, 73, 148, Rack. For the inner side, 12, 13, 14, 15, 16, 17, 19, 22, 26, 33, 46, 87, Rack. Now these numbers, although strictly correct, would be very inconvenient and uncouth in practice if employed for a table like that in question, where convenience manifestly requires that the numbers, if not consecutive, should...
Página i - PRINCIPLES of MECHANISM, designed for the Use of Students in the Universities, and for Engineering Students generally.
Página 107 - Willis deduces the corollary, that if for a set of wheels of the same pitch a constant describing circle be taken and employed to trace those portions of the teeth which project beyond each pitch line by rolling on the exterior circumference, and those which lie within it by rolling on its interior circumference, then any two wheels of the set will work correctly together.