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 viii
... effect of the wheel - work , so far as it governs the relative velocity of the hands , is the same , by whatever cause the motion may be produced , as , for example , when the minute- hand is turned by the finger . " After these general ...
... effect of the wheel - work , so far as it governs the relative velocity of the hands , is the same , by whatever cause the motion may be produced , as , for example , when the minute- hand is turned by the finger . " After these general ...
Página xiii
... effects . I have taken a different course from the one hitherto followed , in respect that instead of considering a machine to be an instrument by means of which we may change the direction and velocity of a given motion , I have ...
... effects . I have taken a different course from the one hitherto followed , in respect that instead of considering a machine to be an instrument by means of which we may change the direction and velocity of a given motion , I have ...
Página xiv
... effect of the combination upon the Velocity Ratio of the pieces , and upon the relation of their directions of motion , or Directional Relation ; from which considerations I have divided all the Elementary Combinations into three ...
... effect of the combination upon the Velocity Ratio of the pieces , and upon the relation of their directions of motion , or Directional Relation ; from which considerations I have divided all the Elementary Combinations into three ...
Página xix
... effects of force and resistance ; which may be con- sidered as carrying out a portion of the plan above alluded to , as necessary to complete this arrangement of the science of Machinery . I am not without hopes , that in addition to ...
... effects of force and resistance ; which may be con- sidered as carrying out a portion of the plan above alluded to , as necessary to complete this arrangement of the science of Machinery . I am not without hopes , that in addition to ...
Página 103
... hitherto made to compare these two kinds of friction . 112. To examine the effect of a constant addendum upon the ratio of the arcs of approach and recess , put E = e in ( 2 ) ; F2 f2 N 2+ 2n + N n = 2N CLASS A. TEETH OF WHEELS . 103.
... hitherto made to compare these two kinds of friction . 112. To examine the effect of a constant addendum upon the ratio of the arcs of approach and recess , put E = e in ( 2 ) ; F2 f2 N 2+ 2n + N n = 2N CLASS A. TEETH OF WHEELS . 103.
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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.