Bicycles & Tricycles

A Classic Treatise on Their Design and Construction

Archibald Sharp

• Éditeur: Dover Publications
• Année: 2013
• ISBN:
  9780486142784

Up until the publication of this book in 1896, no comparable work existed on the science, design, and mechanics of the bicycle — an invention that revolutionized transportation for the average person and had far-reaching social and economic consequences. While other books on the bicycle have been written since, this late-19th-century classic remains unsurpassed in the thorough, accurate, and highly accessible coverage of every aspect of bicycle design and construction. Over 560 illustrations, diagrams, figures, and tables complement an exhaustive examination of such topics as the development of cycles, kinematics, stability, steering, the frame, gears, stresses, mechanical components, and much more. A marvel of scientific exposition for its time, this fascinating treatise will attract a wide audience of readers interested in technology and invention as well as serious and competitive cyclists, bicycle designers, and collectors.

PART I

PRINCIPLES OF MECHANICS

CHAPTER I

FUNDAMENTAL CONCEPTIONS OF MECHANICS

1. Division of the Subject.—Geometry is the science which treats of relations in space. Kinematics treats of space and time, and may be called the geometry of motion. Dynamics is the science which deals with force, and is usually divided into two parts—statics, dealing with the forces acting on bodies which are at rest ; kinetics, dealing with forces acting on bodies in motion. Mechanics includes kinematics, statics, kinetics, and the application of these sciences to actual structures and machines.

2. Space.—The fundamental ideas of time and space form part of the foundation of the science of mechanics, and their accurate measurement is of great importance. The British unit of length is the imperial yard, defined by Act of Parliament to be the length between two marks on a certain metal bar kept in the office of the Exchequer, when the whole bar is at a temperature of 60° Fahrenheit. Several authorised copies of this standard of length are deposited in various places. The original standard is only disturbed at very distant intervals, the authorised copies serving for actual comparison for purposes of trade and commerce. The yard is divided into three feet, and the foot again into twelve inches. Feet and inches are the working units in most general use by engineers. The inch is further subdivided by engineers, by a process of repeated division by two, so that

&c., are the fractions generally used by them. A more convenient subdivision is the decimal system into

&C. ; this is the subdivision generally used for scientific purposes.

The unit of length generally used in dynamics is the foot.

Metric System.—The metric system of measurement in general use on the Continent is founded on the metre, originally defined as the

part of a quadrant of the earth from the pole to the equator. This length was estimated, and a standard constructed and kept in France. The metre is subdivided into ten parts called decimetres, a decimetre into ten centimetres, and a centimetre into ten millimetres. For great lengths a kilometre, equal to a thousand metres, is the unit employed.

1 metre	=	39·371 inches	=	3 2809 feet.
1 kilometre	=	0 62138 miles.
1 inch	=	25 3995 millimetres.
1 mile	=	1 60931 kilometres.

3. Time.—The measurement of time is more difficult theoretically than that of space. Two different rods may be placed alongside each other, and a comparison made as to their lengths, but two different portions of time cannot be compared in this way. ‘Time passed cannot be recalled.’

The measurement of time is effected by taking a series of events which occur at certain intervals. If the time between any two consecutive events leaves the same impression as to duration on the mind as that between any other two consecutive events, we may consider, tentatively at least, that the two times are equal. The standard of time is the sidereal day, which is the time the earth takes to make one complete revolution about its own axis, and which is determined by observing the time from the apparent motion of a fixed star across the meridian of any place to the same apparent motion on the following day. The intervals of time so measured are as nearly equal as our means of measurement can determine.

The solar day is the interval of time between two consecutive apparent movements of the sun across the meridian of any place. This interval of time varies slightly from day to day, so that for purposes of everyday life an average is taken, called the mean solar day. The mean solar day is about four minutes longer than the sidereal day, owing to the nature of the earth’s motion round the sun.

The mean solar day is subdivided into twenty-four hours, one hour into sixty minutes, and one minute into sixty seconds. The second is the unit of time generally used in dynamics.

4. Matter.—Another of our fundamental ideas is that relating to the existence of matter. The question of the measurement of quantity of matter is inextricably mixed up with the measurement of force. The mass, or quantity of matter, in one body is said to be greater or less than that in another body, according as the force required to produce the same effect is greater or less. The mass of a body is practically estimated by its weight,...