These bobbins are so arranged, between the two rollers above mentioned, that the threads proceeding from them accompany the longitudinal threads to the upper roller, and are attached thereto. Each of the longitudinal threads, in its way to the upper roller, passes through a conical tube, or spindle, at the lower cnd of which is a small pinion ; and the spindle is so supported as to be capable of turning round. On the upper end of the spindle is a taper tube, composed of two parts, which, when put together, form a tube ; but the two parts will separate in the direc tion of the length of the tube. One of the parts of the tube, so divided, remains attached to the spindle, and is thereby sustained, so that it will partake of the revolving motion of the Spindle.
The longitudinal thread which passes through the spin dle, is conducted through the hollow part of this half tube, and through a small eye at the extreme point of it.
The other section, or portion of the tube, can be se parated from the spindle, and contains within its hollow part the small bobbin on which the diagonal thread is wound.
When the latter section, with the bobbin, is applied upon the other portion which is attached to the. spindle, the two form a long taper tube, or spindle, containing a pair of threads, viz. a longitudinal thread, which comes up from the lower roller, and passes through the hollow spin dle and the half tube attached to it ; also a diagonal thread, which comes from the bobbin contained in the hollow be tween the two sections.
These spindles are mounted in collars, so as to be cape )le of turning round by means of the pinion at the lower extremities, and when so turned will twist the bobbin and longitudinal threads together.
The number of these tubes or spindles is just equal to the number of pairs of each kind of threads ; and their ar rangement is such, that all the pinions lie in the circum ference of a circle, and the spindles and tubes converge to the centre of the same circle in the manner of radii. All the pinions can be moved round at the same time by rack work, the teeth of which correspond with the pinions. This motion is to cause the pairs of threads contained in each tube to twist together ; tr.id this twisting•takes place in all the tubes at the same time.
The crossing of the diagonal threads over each other is performed in the whole breadth at once, as follows : That moveable part of each divided tube, which contains the bobbin of diagonal thread, can be removed from the other portion, and the bobbin will come away with it ; also any of the separated portions, with the bobbins, will fit and attach to any of the parts attached to the spindles. By a
very ingenious piece of mechanism, the whole number of these moveable parts can be detached from the spindles, and brought forward altogether until they are clear of the spindles.
During the time they are so detached from the spindles, one half of them are caused to move one space to the right, and the other half one space to the left.
The lifted parts are then put back again, and attached to the spindle; but, by this operation, each spindle will have changed its diagonal thread, without having changed its longitudinal thread. This effects the crossing of the threads throughout the whole breadth of the machine at the same time.
The pins by which the uniformity of the meshes is pre served, arc all placed upon a moveable bar, and are all inserted at once into the meshes formed by the two opera tions of twisting and crossing. The working of the ma chine is a regular succession of the three operations of twisting, crossing, and taking up the meshes.
Thus the twisting is performed by the revolution of the spindles and tubes containing the two threads to be twisted.
The crossings are then made by one motion, which in terchanges the bobbins containing the diagonal threads.
The pins are then all introduced at once, to regulate the new meshes formed by the crossing and twisting.
This machine can be worked with great rapidity, by means of handles and treadles disposed in nearly the same manner as in a stocking-frame. It is calculated to make lace of such breadths as are usually made by the cushion, which seldom exceeds three inches ; but it is not capable of any great width, from the circumstance of the conver gence of the spindles and tubes to a centre.
The object of this convergence is to obtain a sufficient space between the spindles for the pinions and bobbins; whilst the extreme points of the tubes, where the pairs of threads issue, are necessarily very close together : and at these points the lace is formed.
Mr. Heathcoat, in 1809, invented another machine, which is adapted to make lace of any required breadth ; and as the mechanism is much less complicated, it has superseded the use of the former machine.