The principal part of the whole, and that to the accu racy and regularity of whose motions it will be necessary to pay the most sedulous attention, is that represented at BB and FF, or what may, without impropriety, be term ed the meshing frame of the machine. In order to con vey as ample and clear an idea of the nature and action of this part, it will be proper to refer to Plate CXXXIX. Figures I, 2, 3, 4. where it is represented in various points of view, and upon a much more enlarged scale.
Construction and Use of the Meshing Frame In Plate CXXXIX. Figs. 1 and 2, are two vertical re presentations of this part of the machine, shelving the different forms which it assumes in various stages of the operation. Fig. 1 it in its close state ; that is to say, in the way in which it appears after the formation of the mesh and the knotting to secure it are completed. Fig. 2 represents it in its open state, as it appears pre vious to, and during the formation of, the mesh and knotting. In Fig. 3 is given a horizontal plan of the same apparatus, necessary to elucidate sonic of the prin ciples of its construction, and mode of its operation ; and in Fig. 4 is given a section of the bobbins upon which the twine is wound, to explain also their particular construc tion and operation. This last, like Fig. 1 and 2, is a ver tical representation or elevation.
In order to form the ring knot, it is well known that two twines or cords are to be laid parallel to, and in con tact with, each other ; that they are then turned round in a circular form, similar to that of a ring, (whence proba bly the name is derived,) and one end of both twines be ing passed through the ring, the knot is completed. This mode of knotting seems to afford a particular ad vantage over all others not liable to slip in this respect, that the two twines to be knotted being parallel and con tiguous to each other, the requisite motions and crossings of both are precisely the same, and consequently when knotted by the aid of machinery, the process becomes more simple than where the motions of the two twines and their flexures and crossings are different. The twine of the net being wound upon bobbins, and these disposed in pairs, so that two threads may be contiguous, and the further extremities attached to the receiving beam, we arc ready to commence the operation, the mesh frames being in the open state as represented by Fig. 2. It is proper to keep in mind, however, that there are four up right arms in each frame similar to those at CC, although only two are represented, the other two being at right an gles to those which appear at B, which will be very plain by inspecting the horizontal plan, Fig. 3. The whole four diverging equally, form a diamond, and by passing two twines round at the points CC, a ring is formed for the knot. When the twines are thus passed round so as to form somewhat more than a circle, that part which crosses must be done below the other. If the bobbins are then raised, brought over the ring, again sunk in its centre, and pulled tight, the ring knot will be complete, and the tension of the ends will close the frame until the points meet in the centre, as in Fig. 1. The knot may be then slipped off, and the upright arms at CC will revert to the open state by their own gravity. This may be very well seen by inspecting Fig. 3. It is thus that the ring knot may be formed with the greatest accuracy and dis patch ; and were the same twines always contiguous and knotted together,'the operation would be simple indeed. But it is evidently necessary to complete the diagonal or diamond shape of the mesh, that the contiguity of the twines should be changed at every alternate knotting. Thus at one knotting, the twines I 2, 3 4, 5 6, &c. (see Fig. 5.) should be contiguous, and, at the next, that 2 3, 4 5, &c. should come into contact. For this purpose some addition is necessary to the apparatus, and an idea of its construction and use will be gathered from Figs. 3 and 4, Plate CXXXIX.
In addition to the exterior apparatus or folding arms of the frame, another part is necessary, which is partially represented at L, Fig. I, but which will be better under stood by referring to Figs. 3 and 4. Fig. 3 exhibits a horizontal plan of the meshing frame and contiguous apparatus. The standards upon which the upright arms of the frame are jointed, appear plainly as quadrants of a circle at DDDD. That part of the apparatus which directs the operation of the bobbins at L, will also be distinctly seen in this figure. When the operation com mences, the apparatus L, which moves horizontally on a centre, is in the situation of L 2, that is to say, just without the circumference of the meshing frame. Now
let the whole apparatus of this frame revolve upon the common centre of motion, or spindle which supports it, (A, Fig. 1.) and the two contiguous twines at NIT, &c. Avill form the ring of the knot, the arms of the meshing frame serving to keep the ring distended. The two bobbins being at the lower part of the spindle on which they revolve, will cross under the twines which are round the frame at the point near M. The bobbins are then to be raised upon the upper spindle. The cross rail, with projecting pins at 0, being next shifted in a direction towards the upper part of the figure, the apparatus at L will change its position until it is right over the centre of motion, when the bobbins being let down into the centre of the ring, the knot will be formed, and the dis tended arms brought into contact as in Fig. 1. An invert ed shift of the shaft 0 will then bring the bobbins again without the ring, and one series of meshes will be com pleted. The next operation, then, will be to change the contiguity of the bobbins for the next mesh. In order to effect this, reference may be made to the vertical section, Fig. 4. In this figure the vertical spindles are placed at a little distance, the one being perpendicularly over the other. This interval or chasm is to allow them to change freely from the outside to the inside of the ring after it has been formed, the twines passing through the inter val. The lower part of the bobbin spindle A 1, moves upon the centre at I), as already described. All the up per parts at A 2 arc fixed in a shaft of wood F, extending the machine. This shaft, by means of grooves or slit holes, slides freely from side to side 111)01) another shaft F, and this latter shaft, by means of a crank at each end, is susceptible of the same motion as that at A below, so that one may be always perpendicularly ()vet -the other. In order to guard as much as possible against those trivial inaccuracies to which machinery of every kind is in some degree liable, it may be proper to giu e each spindle a sharpened point, so that they may approach each other like inverted cones. lf the bobbins be also countersunk at each end, there will be little danger of their missing the proper direction while shilling ups ands or downwards, or presenting any obstruction to the ope ration. The section of B and C will serve to render this obvious. In bringing the spindles to a point, it trill not be necessary that it should be very acute, for, if the bobbins are of wood, this would rather be prejudicial than of any service. A row of meshes being finished, the receiving beam is to be moved one notch off the regulat ing wheel, in order to wind up a portion of finished Oct equal to one mesh. A second row of meshes being then formed, are to be wound up as before, and so on until the whole operation is completed. From the above de scription a general idea of the operation may lie gathered, and this is perhaps as much as can be expucted without an actual model. In the next place. it may be proper to pay some attention to the general operation, and of this perhaps the most accurate idea may be formed by a re gular analyses of the respective motions of the projected reticulator. Let us suppose that a mesh has just been completed, and wound up on the receiving beam, and that we are then proceeding to form a second row, the motions then will occur in the following succession: 1st, The shifting motion of the upper bobbin. At this stage of the operation, both bobbins are upon the lower spindle ; but as the upper bobbin is to be shifted, those must first be lifted upon the upper one. This may very easily be accomplished, by hanging a shaft above, with a vertical motion, and furnished with wire hooks corres ponding to each bobbin. If a small groove is turned in both bobbins, either one or both may be lifted at pleasure. For if the hooks lay hold of the lower bobbin, both must rise ; and if, as in this case, the upper only is laid hold 4, the under will not be at all affected. When the up per bobbin has been lifted, the shaft may be moved from right to left, or vice versa, as the case may be, and the shift completed. This operation may be effected easily by one or both of the operator's hands. This part of the apparatus is so simple, that it has not been deemed ne cessary to give any drawing ; although this deficiency, if the experiment were to be tried, might very easily and speedily be supplied. The shift being completed, both bobbins are to he let down upon the lower spindle, arid each should be furnished with a small eye to guide the twines properly round the meshing-frame. The appara tus is now ready for the second motion.