Description
International Textbook Company, Published 1940. Hardcover, v, 44, 56, 57 pp.; 20 cm; illustrated with black-and-white line engravings and dimensioned working drawings throughout, including double-page plates.
Rare, out-of-print & unusual books · Since 1997
112
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Catalog notes
Condition & notes
In Very Good condition, no dust jacket. Black pebble-grained cloth, blind-stamped title panel with ornamental device below on front cover, blind-stamped publisher's panel at foot, gilt lettering on spine bright, reading from the foot upward as in all volumes of the series. Mild surface and edge wear, with tiny nicks to the cloth at the tips of the top corners, front and back. Binding tight. Green and cream marbled endpapers, blue-stained page edges. Pages clean and unmarked. Volume 504C in the bound series issued by International Textbook Company, the publishing arm of the International Correspondence Schools of Scranton, Pennsylvania. ICS grew out of a mine-safety question-and-answer column run by Thomas J. Foster in the Colliery Engineer and Metal Miner and enrolled its first class of 500 miners in 1891; cumulative enrollment reached four million by 1930, making it the most successful correspondence school in American history. The bound volumes gathered the loose serial-numbered Instruction Papers into permanent form, this one comprising Walschaert Valve Gear Part 1 (Serial 4003A-2, Edition 2), Part 2 (Serial 4003B, Edition 3), and Baker Locomotive Valve Gear (Serial 5370, Edition 1), by J. W. Harding, credited on the title page as Director of the Steam Railroad Schools of the International Correspondence Schools. The text opens with the history, that the gear was invented by Egide Walschaerts in 1844 and that American practice dropped the final letter of his name, that it was little used on American locomotives until about 1900 when engines had grown too large to carry a Stephenson gear between the wheels, and that by the date of this printing the Walschaert had entirely superseded the Stephenson on new construction. Part 1 works through the principles, why the gear is not reversible, the action of the cranks, the movement imparted by the reverse lever, oiling points, then the hardware, types of gear frames, radius-rod hangers and reverse-shaft cranks, the eccentric crank and its position for direct and indirect motion, link arc and link radius, constant lead and the curvature of the link compared with the Stephenson, crossed lead and unequal valve travel, and closes with the dimensions of the gear. Part 2 is the parts in detail: gear frame, cross-ties and guide yokes, eccentric crank and rod, the three-piece case-hardened link and its bracket pieces, radius rod, combination lever, radius-rod hanger, reverse-shaft crank and arm with the several arrangements of valve-stem crosshead and guide, then reversing, change in cut-off, and the back-set of the link foot. The third section takes up the Baker gear, the American linkless design, comparing it directly with the Walschaert, then its arrangement and details down to the reverse yoke, radius bars, bell-crank and gear connecting-rod, the proportioning of the combination lever and the changing of lead, followed by the movement of the parts through one turn of the driving wheel, admission, cut-off and release at both ports, and the effect of angularity of the rods. Both the Walschaert and the Baker sections end with a chapter on breakdowns, the road repairs an engineer had to make with a broken eccentric crank, eccentric rod, radius rod, combination lever, union link or gear reach rod, and how to block or tie the gear to bring the train in on one side. Copyrights run 1935, 1930 and 1924 for Part 1, 1934, 1930 and 1924 for Part 2, and 1940 for the Baker section, with no periodic-review notice or later edition date. Printed at the International Textbook Press, Scranton, printer's key 83509 at foot of the copyright page; the plates are signed BB 504B 4003A, struck for the earlier 504B compilation and carried over into this one. Contents: Walschaert Valve Gear, Part 1: Arrangement and Operation; Introduction; Principles Underlying Gear; General Description; General Operation; Types of Gear Frames; Types of Radius-Rod Hangers; Types of Reverse-Shaft Cranks; Eccentric Crank; Position of Eccentric Crank; Link Arc and Link Radius; Crossed Lead; Radius-Rod Movement and Valve Travel; Dimensions of Walschaert Valve Gear. Walschaert Valve Gear, Part 2: Arrangement and Operation (Continued); Gear Frame; Cross-Ties and Guide Yokes; Eccentric Crank; Eccentric Rod; Purpose and Construction of Link; Radius Rod; Combination Lever; Radius-Rod Hanger; Reverse-Shaft Crank and Reverse-Shaft Arm; Reversing; Change in Cut-Off; Back-Set of Link Foot; Breakdowns. Baker Locomotive Valve Gear: Arrangement and Operation; Introduction; Underlying Principles; Comparison of Gears; Arrangement of Parts; Details of Parts; Operation of Gear; Movement of the Parts; Gear Movement During One Turn of Driving Wheel; Effect of Angularity of Rods or Cut-Off; Breakdowns.