Whatever particular character these weft-replenishing devices assume, they may be broadly classified under one or other of two distinct types, namely, (1) that in which the same common shuttle is replenished with cops or bobbins of weft; and (2) that in which a fresh shuttle replaces the previous one. Each of these two broad divisions comprises numerous modifications in both their construction and also in the manner in which they operate.
Of the cop-or bobbin-changing type of loom, the “Northrop” loom, invented in Hopedale, Mass., U.S.A., by James H. Northrop (a native of Keighley, Yorks.), has gained a greater measure of success than that of any other automatic loom; and of the shuttle-changing type, the “Hattersley” loom, invented by Simeon Jackson, of Geo. Hattersley and Sons, Limited, Keighley, Yorks., has probably found greater favour than others of that type. Looms of the Northrop type require essentially the use of shuttles of special construction that are capable of self-threading the weft; whereas looms of the Hattersley type may weave with the same kind of shuttles as those employed in ordinary power-looms. Looms of both types are constructed so that the change of weft is effected instantaneously whilst they are running at full speed, without any loss of time; but when a change of weft takes place in the Hattersley modification of the shuttle-changing type, the looms stop running automatically for a few picks to allow more time for the changing of shuttles, after which the looms re-start automatically and continue running at full speed.
In addition to the essential elements constituting a successful weft-replenishing device, this requires to be supplemented by numerous appliances of a special character to ensure the general efficiency of the loom. For example, at that side of the loom on which the replenishment of weft is made, there is fixed a weft-cutting device to sever the superfluous trail of weft close to the selvedge of cloth after the insertion of each fresh supply of weft. In some looms the weft is replenished only when the previous supply fails either by breaking or becoming exhausted; and some are furnished with “weft-feeler” motions to put the weft-changing mechanism into operation and thus replenish the weft just before the previous supply is entirely depleted, thereby preventing broken or missing picks of weft which would produce faulty cloth. A warp-stop motion, which is sometimes applied to ordinary looms, is an almost indispensable accessory to an automatic loom. Its function is to detect the breakage of warp-ends, and to stop the loom automatically whenever that occurs. These remarks apply also to the controlling of the tension and delivery of the warp, which are sometimes effected automatically in looms of any description.
Up to the present time weft-replenishing devices are almost exclusively restricted to single-box looms employed in the production of standard varieties of fabrics of comparatively simple construction, and containing but one kind of weft requiring the use of only one shuttle. These devices have, however, been employed on check-looms weaving with more than one kind of weft, and therefore requiring the use of a corresponding number of shuttles at the same time; but automatic check-looms have not yet passed the experimental stage and become established on a commercial basis, although there are prospects of this taking effect in the near future.
Having thus far introduced the reader to what constitutes the chief elements of an automatic or self-acting loom, it will, at this stage, and before examining the details of their special mechanism, be both instructive and profitable to briefly survey the work of pioneers in this sphere of invention, as revealed in the records of the numerous Letters Patent that have from time to time been granted for inventions of devices for the automatic replenishing of weft in looms, and to trace the origin and development of such devices from the earliest authentically recorded date of their inception down to the present time.
From a research of the earliest published records of patents relating to weaving, which records date from 15th July, 1620, it would appear that the credit for the first patent for an automatic weft-replenishing device for looms is due to Messrs. John Paterson Reid and Thomas Johnson, both of Glasgow, who are the joint patentees of an invention of such a device described in the Patent Specification, dated 20th March, 1834, No. 6579. This is a large document of 69 pages of text comprising over 35,000 words and 12 sheets of diagrams. It describes in a very lucid manner several improvements in power-looms, of which that relating to the automatic replenishing of weft is treated almost as if it were regarded, by the inventors, as of only secondary importance to the other improvements which they describe.
In view of the great progress which has been made within recent years in the development of these looms, and also in consideration of the fact that a patent, which was granted to Charles Parker nearly seven years subsequently, and is described in the Specification dated 22nd October, 1840, No. 8664, has been frequently cited as the first patent relating to the automatic supply of weft in looms, the first-named document acquires a special interest, not only as a record of what is probably the first attempt in that direction, but also because it establishes, beyond refutation, the date and rightful title to the first patent granted for such an invention.
In the former specification, the patentees state that their improvements are applicable to what were then known as Johnson’s vertical power-looms, in which the warps were extended vertically from the warp-beam at the bottom to the cloth-roller at the top of the loom; and the reed, which served as the shuttle-race during the flight of the shuttle through the warp-shed, moved in a vertical plane when beating up the weft. These vertical looms were made double, to permit of two pieces of cloth being woven in them at the same time; but they had evidently been discarded, and were not then in use amongst manufacturers. The looms made according to Reid and Johnson’s specification were so very different from Johnson’s looms as to have very little in common with them excepting that they also were vertical power-looms in which the warps extended vertically. The specification states that the “great object” of their improvements is to enable four webs or pieces of cloth to be woven simultaneously and at one operation in the same loom, with only one slay which has a vertical motion, and also that the warps for the four webs are to be wound on two separate warp-beams. After describing in minute detail the construction of the improved loom, the patentees proceed to describe their invention of a device for the automatic supply of weft to their looms whilst these continue running. This part of their invention is introduced as if it were quite incidental and of little consequence, and is described as the “accessories and new improvements” which they apply to their vertical power-looms, as follows:—