Morrison's Spring Tables Design Reference

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Morrison's Spring Tables Design Reference

Engineering Applications and Design
Spring Design and Engineering

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Morrison's Spring Tables Design Reference

Preface

In offering this book to the public, the author desires to call attention to the general scheme which has been followed.

Springs fall naturally into two classes, light and heavy: in the case of helical springs called wire and bar; in elliptical springs called sheet and plate. In the following pages the writer has considered a helical spring whose bar is less than one-sixteenth of an inch in diameter, or an elliptical spring whose plate is less than one-sixteenth of an inch in thickness, to be a light spring.

In helical springs the ratio between the diameter of the bar (or similar dimension in other than circular sections) and the mean diameter of the spring forms the basis of calculation in estimating the various properties of the spring. In elliptical springs the basis of calculation is the ratio between the thickness of the plate and the span or net length of the spring. The span or net length of a spring is the distance between centers less the width of the band.

The properties of heavy springs may be arranged easily under each size of bar or thickness of plate, inasmuch as the number of fundamental ratios for each bar is practically definite. On the other hand the numerous gauges of wire and sheet and the extremely small differences which are made in the dimensions of light springs render the number of fundamental ratios for light springs prohibitive to a table of spring properties for each gauge.

In the present tables, therefore, the writer has arranged the properties of light springs under graduated values of the funda- mental ratio, so that the properties of any light spring may be quickly determined from its peculiar ratio. The properties of heavy springs are tabulated under each size bar or plate.

The table on rectangular and elliptical sections is designed for use in connection with the other tables on helical springs, the properties of springs made of such sections being easily determined by proportion. The sections considered are sections of the bar after coiling. A rectangular bar will not produce a rectangular section spring.

The mathematical tables are included to facilitate the use of formulae.

One inch of solid height has been taken as a working basis in the case of helical springs; while for elliptical springs the basis has been taken as one plate one inch wide.

All calculations presented in this book are based on a fiber strain of 80,000 pounds per square inch. The modulus of elas- ticity is taken at 12,600,000 for helical springs, at 25,400,000 for elliptical springs. These figures are good practice for ordinary heavy steel springs. Calculations of springs made of material having other physical properties are simple proportions employ- ing such properties find the tabulated values of steel springs.

Throughout the book the loads are given in pounds while all dimensions are in inches.

TOC

PART I. FORMULA.
NOTATION 8
HELICAL ROUND BAR SINGLE COIL GENERAL 9
HELICAL RECTANGULAR BAR SINGLE COIL GENERAL 10
HELICAL ROUND BAR SINGLE COIL STEEL 11
HELICAL RECTANGULAR BAR SINGLE COIL STEEL 12
HELICAL CONCENTRIC COILS 13
ELLIPTICAL GENERAL 14
ELLIPTICAL STEEL 15
PART II.
MATHEMATICAL TABLES. FRACTIONAL PARTS OF K 18
CUBES 18
FIFTH POWERS 19
SPRING TABLES. HELICAL WIRE LIGHT STEEL SPRING TABLE 22
HELICAL BAR MACHINERY AND RAILROAD HEAVY STEEL SPRING TABLE 25
HELICAL RECTANGULAR AND ELLIPTICAL SECTIONS 75
ELLIPTICAL SHEET LIGHT STEEL SPRING TABLE 77
ELLIPTICAL BAR CARRIAGE MEDIUM WEIGHT STEEL SPRING TABLE 78
ELLIPTICAL PLATE MACHINERY AND RAILROAD HEAVY STEEL SPRING TABLE 79
ELLIPTICAL TAKE-UP 84