The Project Gutenberg EBook of Tappet and Dobby Looms, by Thomas Roberts This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: Tappet and Dobby Looms Their Mechanism and Management Author: Thomas Roberts Release Date: July 15, 2010 [EBook #33176] Language: English Character set encoding: ISO-8859-1 *** START OF THIS PROJECT GUTENBERG EBOOK TAPPET AND DOBBY LOOMS *** Produced by Susan Skinner, Andrew D. Hwang, and the Online Distributed Proofreading Team at http://www.pgdp.net transcriber's note Minor typographical corrections and presentational changes have been made without comment. Figures may have been moved with respect to the surrounding text. This PDF file is optimized for printing, but may easily be recompiled for screen viewing. Please see the preamble of the LATEX source file for instructions. UNIFORM WITH THIS VOLUME THEORY OF SIZING By H. Nisbet. Crown 8vo. Illustrated. 3s. 6d. net. PRODUCTIVE COSTS IN COTTON SPINNING MILLS By Arthur H. Hardman. Crown 8vo. 110 pages. With numerous Tables and Diagrams. 3s. 6d. net. FINE COTTON SPINNING: A Practical Manual By J. W. Lomax. Crown 8vo. Illustrated. 3s. 6d. net. THE MANUFACTURE OF WOOLLEN AND WORSTED YARNS By J. W. Radcliffe. Crown 8vo. 341 pages, with 113 Illustra- tions. 6s. net. PRELIMINARY OPERATIONS OF WEAVING By H. Nisbet. Vol. I.|Preparation of Grey or Plain Warps. Demy 8vo. 388 pages, with 200 Illustrations drawn to scale. 10s. 6d. net. THE FINISHING OF JUTE AND LINEN FABRICS By Thomas Woodhouse. Demy 8vo. 326 pages, with 253 Illus- trations. 8s. 6d. net. HEALD AND REEDS FOR WEAVING By Thomas Woodhouse. Crown 8vo. Illustrated. 4s. 6d. net. IN THE PRESS JUTE AND JUTE SPINNING (Woodhouse & Kilgour.) WOOL CARDING (J. Bradley.) PRELIMINARY OPERATIONS OF WEAVING, Vol. II. (Ball or Sliver Warping). (H. Nisbet.) Manchester: EMMOTT & CO., LTD., 65 King Street London: 20 Bedford Street, W.C. 2 Tappet and Dobby Looms: THEIR MECHANISM AND MANAGEMENT BY THOMAS ROBERTS Head of the Weaving and Designing Departments of the Holmfirth and Dewsbury Technical Institutes, and formerly Lecturer in the Textile Department of the Huddersfield Technical College MANCHESTER EMMOTT & CO., LIMITED KING STREET LONDON: BEDFORD STREET, W.C. [All Rights Reserved] Published April 1912 Reprinted June 1920 PREFACE The object of this work|the greater portion of which originally ap- peared as a series of articles in The Textile Manufacturer|is to help those who are engaged in the weaving industry to obtain a fuller knowl- edge of the mechanism and management of the loom. At the same time it is hoped that the book will supply a much-needed addition to the scanty literature at present available on this particular branch of the manufacturing processes. A special feature of the subject-matter is the references to defects produced in fabrics during weaving, these being drawn from observa- tions made by the author during his many years' practical experience of the subject. The illustrations employed to elucidate the construction of the vari- ous motions are chiefly line drawings|drawn to scale|from well-known types of looms. The detailed descriptions of the motions have been expressly included for the sake of students following out a course of technical instruction|the author, as a teacher of textile technology, having experienced a long-felt want in this particular direction. Thomas Roberts. Huddersfield, April . v DUNEDIN PRESS LTD., EDINBURGH. CONTENTS CHAPTER I CLASSIFICATION OF POWER LOOMS PAGE Installation and Arrangement of Looms|Right and Left Hand Looms| Driving of Looms|Brake Motions|Balance Wheel|Friction Driving|Features and Advantages of the Indirect Driving Motion| Speed and Production|Speed Calculations|Transmitting Motion throughout the Loom . 1 CHAPTER II MOTIONS OF THE LOOM Beating-up Motion|Construction of the Going Part|Wood and Iron Shut- tle Races|Movement of the Going Part and Flying Shuttle|Stroke of the Going Part|Its Effect on Speed of the Loom and Weaving Qualities of the Warp|Nature of the Motion Imparted to the Go- ing Part|Motion of the Going Part during the time the Crank is turning about the four Centres|Factors which Influence the Eccen- tric Motion of the Going Part|Position of the Reed when Beating- up|Resistance of the Warp to the Beat-up in different Weaves| Relation and Timing of the Various Motions|Picking Motion| Shedding Motion|Box Motion—Letting-off and Setting-up Motions 27 CHAPTER III SHEDDING MECHANISM Sectional Tappet|Barrel Tappet|Bradford Tappet|Driving the Tap- pets and Change Wheel Calculation|Variety of Weave Effect— Tappet Construction|Method of Drawing the Outline of a Tappet| Nature of the Motion desirable for the Healds|Reversing Motions for Tappet Mechanism|Weights|Springs|Heald Pulleys|Stocks and Bowls|Kenyon's and similar Under-motions|Positive Tappet Mechanism . 45 vii viii TAPPET AND DOBBY LOOMS CHAPTER IV DOBBY MECHANISM PAGE Timing and Setting|Harmonic Motion of the Heald|Jack-missings| Lever Dobby|Hattersley Double-action Open-shed Dobby|Centre Closed-shed Dobby|Cross Border Dobby|Defective Shedding| Reediness in Cloth|Uneven Shedding|Badly-formed Selvages| Weft Staplings|Depth of Shed and its Effect on the Warp|Perfect Slope of Shed|Easing the Strain on Dobby Mechanism . 75 CHAPTER V PICKING MECHANISM Shuttles|Shuttle-box and its Influence on the Shuttle|The Pick|Picking Motions|Timing and Setting|Defective Picking|Over-pick|Pick- at-will Motion|Shuttle-easing Motions|Shuttle-checking Motion| Defective Checking|Under-pick Motion|Timing of the Pick| Setting the Pick|Early and Late Picking|Defects in Picking Motions|Tight and Slack Shuttle-boxes|Waste of Weft|Pickers and Picking Straps . 101 CHAPTER VI SHUTTLE-BOX MECHANISM Setting the Boxes|Chain-making for Box Motions|Features in Chain- making|Building up Box Chains|Complicated Weft Plans| Circular Box Motion|Indicating to the Boxes|Circular Skip-box Motion|Working of Circular Box Motions|Pattern Chains . 121 CHAPTER VII LET-OFF MECHANISM Negative Let-off Motions|Varying the Tension of the Warp|Causes of Defective Working|Advantages and Disadvantages of this Class of Motion|Positive Let-off Motions|Regulating this Class of Motion 153 CONTENTS ix CHAPTER VIII TAKE-UP MECHANISM PAGE Negative Motions|Automatic Regulating Motion|Features of Negative Motions|Positive Take-up Motions|Features of Positive Motions| Calculations for Take-up Motions . 169 CHAPTER IX AUXILIARY MECHANISM Weft Stop-motion|Centre Weft-fork|Defects due to Weft Stop-motions| Warp Protector Motion|Fast Reed Motion|Warp Stop-motion| Electrical Warp Stop-motion|Temples|Types of Temples|Roller Temples|Summary of Defects Caused by Temples|Selvages| Selvage Motions|Centre Selvages|Doup Heald . 181 Index..................................................................... 207 x TAPPET AND DOBBY LOOMS TAPPET AND DOBBY LOOMS THEIR MECHANISM AND MANAGEMENT CHAPTER I CLASSIFICATION OF POWER-LOOMS Looms may be divided into three classes|namely, (a) tappet, (b) dobby, and (c) jacquard looms. Other methods of classifica- tion are sometimes adopted|e.g., according to the class of fabric for which the looms are specially adapted, as light goods tappet loom, heavy woollen loom, fancy coating box loom, and fancy cotton dobby loom; whilst they are also referred to by the name of the maker or place of manufacture. It will be evident, from the many terms of clas- sification, that no definite line of demarcation can be drawn, although in some districts one style or class of loom preponderates. The most general method in vogue is that which differentiates according to the style of the shedding motion employed. Tappet looms are so named by reason of the mechanism employed to control the healds. This class includes the plain loom fitted with inside tappets to take from two to eight heald shafts, or with outside tappets to accommodate up to twelve shafts. The latter type of loom is often styled the Bradford tappet loom, as it is largely used in that district. The plain loom fitted with the Woodcroft and other styles of tappets is also included in this class. Many tappet looms are mounted with boxes, usually circular boxes, at one or both sides. Generally speaking, such looms are employed to weave calico, plain dress goods, linings, plain coatings, serges, meltons, beavers|in short, any class of fabric which does not require a large number of healds, and in which the weave is complete on not more than 12 picks. Dobby looms are so named on account of the healds being operated by dobby mechanism, which is 1 2 TAPPET AND DOBBY LOOMS entirely different in its construction from tappet mechanism. Dobbies are made to accommodate 48 shafts, but 16, 24, and 36-shaft dobbies are most common. This class of loom admits of variety in weave effect, and may yield more extensive patterns than the tappet loom. It is usually mounted with a series of boxes at both sides, generally four, though for weaving certain goods six boxes are requisite; the loom may also be fitted with two warp beams. The range of fabrics produced in this loom is very wide, and includes fancy coatings, trouserings, fancy dress goods, mantle cloths, cap tweeds, mauds, and rugs. The term \jacquard looms" has reference to those looms which are mounted with a jacquard machine. The advantage of such looms, when compared with the dobby and tappet looms, is the increased figuring capacity, as the number of threads which a design may occupy is practically unlimited. Fabrics of an ornamental and elaborate character are produced in this loom, of which fancy vestings, figured dress goods, tapestries, plushes, and carpets are examples. Installation and Arrangement of Looms.|The operation of weaving, as well as the preparatory processes, are such that the room in which they are carried on should be well lighted.