Like all successful inventors, Heathcoat had numerous imitators, some of whom, by a re arrangement of the parts of his machine, sought to deprive him of the merits and reward of his invention ; others again, stimulated by his success, sought to improve his machine in many respects, or supersede it by entirely new inventions. One of the most successful of the former was Brown's traverse warp-machine. This and several others were successfully worked for some years, owing to the discovery of a serious flaw in Heathcoat's specification, during the progress of a trial iu an action brought by the latter to' defend his rights. Soon after this, Moore invented a traverse warp-machine embodying considerable mechanical skill, which caused an actiou to be brought against him by Brown. The case was tried, and the principal result, though not the one sought, was to establish the validity of Heathcoat's invention, and to compel both parties to acknowledge his priority, and each as a consequence submitted to pay a royalty to him tor the use of their machines. The inventor and others continued to work at the improvement of this machine for many years, each alteration increasing its capacity or perfecting its work. It has suggested many other changes in lace machinery, and in that respect has contributed greatly to the wonderful development of the lace manufacturing industry of this country.
In 1812, a lace-frame was constructed, called the pusher-frame, which with subsequent im provements has been worked with advantage to a considerable extent. It was the invention of Clark and Mart of Nottingham. It possessed some special advantages, and is stated to have been a clever modification of Heathcoat's machine.
But the most important outcome of the inventive faculty, which was being so extensively uti lized in the Midland districts was the bobbin-net machine of John Levers, another modification of the Old Loughborough machine. This appeared in 1813, and from that date to the present time has continued in use, and has gained ground over all competing machines to such an extent as to have become the leading machine employed in the trade. Levers was originally a and, like many others, encouraged by Heathcoat's success, devoted himself to the improvement of the methods in vogue for the production of lace. His success was remarkable, but he did not possess the high qualities of personal character that distinguished Heathcoat, and so failed to secure corresponding advantages. His machine was subsequently improved by numerous persons, but to detail these would be somewhat tedious. A better course will he to describe the machine in its present perfected form, as the best representative that could be selected of the mechanical lace frame.
The inventor of the Levers' lace-frame held the opinion that as it passed out of his hands it was only in its infancy. This was an accurate observation, for what with subsequent improvements, and the successful application of the jacquard attachment, its capacity has been extended so greatly, that hardly any limit can be put to its power. It is the most delicate of all the lace-making machines, its interior parts occupying the smallest space, and requiring the nicest adjustment.
When arranged to make fancy work, it is also the moat costly. A 10-point machine is about 152 iu. in width, has 80 top bare, 400 bottom bars, 54 threading-beams, and a jacquard to enable it to produce ornamented laces. The framework is heavy and solid ; its parts are highly finished, and its movements accurately adjusted : conditions essential to the satisfactory working of a lace machine.
In Fig. 888, a general view of the machine with the jacquard attachment is given ; the latter con stitutes the right-hand part of the figure, whilst the left is the lace-frame proper. The frameworks of both the machines A A' are massive, strong, and firmly attached to the flooring, in order to prevent vibration. The two parte are connected, and both actuated by the shaft B, which is driven by a strap on the pulleys c, near which is also fixed a balance- or fly-wheel, designed to secure steadiness in working. A shaft D arranged near the top of the back part of the frame carries several cams, and hence is called the cam-shaft ; it is driven by means of a connecting shaft and wheels at the driving end of the frame. A shaft E extends the length of the frame, and by means of the connecting-rod E', is rocked by cranks on the shaft B. Move ment is imparted to the jacquard from the shaft B, through the wheels F. The sectional view, Fig. 889, will help to show the move ments. The warp-beams w extend across the length of the frame, and contain the traversing threads of the fabric, each of which passes through eyelet-holes on the bare at x, and thence are conducted up ward through the plate N and the slide-bars y y, and attached to the lace-beam 0, which receives and winds up the lace as it is made. The bobbin in its carriage is shown at b, the thread from which passes up to the point a, the centre of the aro or osoillatory traverse in which the shuttles move. The car riages slide between the comb or guide-plates c, and as they pass from one comb-bar to the other, they necessarily go between the vertical warp threads. There is an angle-bar at M, and a corresponding one on the oppoaito part of the frame ; these receive the carriages, which protrude through the comb-bar, as they pass through the warp threads, and are called landing-bars. The office of these bars is to receive the carriages, and diminish the friction that would otherwise arise from their large number, amounting to nearly 3000 in a frame of this de scription and width. Each land ing bar has affixed to it at L a catch bar, having a strip or blade which falls into slots f of the carriage Fig. 890, by which means the whole of the carriages are drawn across. On being returned to the oppo site aide, the catch-bar pushes them forward until within reach of the bar on the other aide, the blade of which drops into the groove ; the bar being withdrawn, brings with it the carriages. By these means, the carriages are trans ferred from one side to the other. The advance and recession of the landing- and catch-bars are accomplished by means of the rocking-shaft E, Fig. 888. These constitute the movements of the bobbins carrying the longitudinal threads of the fabric.