The several heckles a a a are formed by a series of needles or heckle points set into a metal bar, as represented on an enlarged scale in [figs. 446.] and [447.] These bars are each of them suspended in a frame or carriage b b b (shown in two views at [figs. 448.] and [449.]), by means of double jointed levers c c, seen in two positions, at [figs. 450.] and [451.]; the heckle bar, its levers and carriage or frame, being shown put together in [figs. 452.] and [453.]
When the heckles are in operation, the points are raised, as in [fig. 452.]; but when they are withdrawn from the fibres, then the points are sunk down into the carrying frames, as [fig. 453.]
These two positions of the heckles are produced by the knobs or parts d, that project from the jointed levers c, acting against the edges of guide bars, which will be explained in describing the operations of the machine.
The several heckles are adapted and made to work in the machine by attaching the ends of the respective frames or carriages b, to travelling endless chains e e, seen in [figs. 443.], [444.], and [445.] These endless chains pass over fluted guide rollers f f, seen best in [figs. 444.] and [445.], and over horizontal bars g g, seen best in [figs. 443.] and [444.] The chains with the heckles are driven through the machine by rotatory spur wheels h h; see [figs. 443.] and [444.], the teeth of which take into the spaces between the cylindrical parts of the several heckle carriages b b, and consequently drive the heckles forward; and these spur wheels are actuated by a train of toothed geer from the first driving shaft i, which gives motion to all the operative parts of the machine.
If flax, hemp, long wool, or other fibrous material, be passed into the machine at the back part by a feeding cloth or creeper through a guide k, best seen in [figs. 443.] and [444.], and be conducted under and over the feeding rollers l, m, and n, and over the heckles a a a to the drawing rollers o and p, and thence to the flyer and bobbin, or to a receiving can, the fibres will be opened in their progress, and combed by the points of the heckles entering into and separating the fibres, the material being drawn by a different speed to that with which the heckles travel.
This operation of preparing, drawing, and roving flax and hemp, and the general construction of a machine of this kind being well understood, it is not necessary to explain its details, excepting as respects those parts which constitute the present improvements.
It will be perceived, by reference to [figs. 443.] and [444.], that the knobs d, which project from the jointed levers c, as they travel along the machine, bear against the outer edges of the two fixed guide bars q q that extend along the top of the machine above the heckles, which keep the heckle points raised, as in [fig. 451.] This will also be very evidently seen in the front view of the machine, [fig. 445.], where the upper heckle bar a is raised in its carriage b, by the knobs d d bearing against the outer edges of these guide bars q q. But when the endless chains e e, which support and conduct the frames or carriages of the heckles, have advanced the heckle points to within a very little distance of the drawing rollers (see [fig. 444.]) then the knob d of the jointed levers at each end of the heckle bar passes the ends of the guide bars q q, and they immediately come in contact with two inclined planes r r, seen in [figs. 443.] and [444.], which instantly depress the levers c, and consequently cause the heckle bar a, with its points to descend in the frame or carriage b, withdrawing the points from the fibres of the material almost in a perpendicular direction.
The heckles that have become thus depressed pass with their carriages by the traversing of the endless chains along the under part of the machine, and when they arrive at the back, and begin to rise, the guide bars q q, being at their commencement slightly bent, conduct the knobs b of the levers c until they are forced back into the positions first described, whereby the heckle points are raised, as they come to the upper part of the machine, into effective operation. The fibres of material operated upon, after passing through the drawing process between the rollers, may be roved, twisted, or spun, by the employment of a bobbin and flyer, as shown in [fig. 444.], or may be delivered into a can, to be roved, twisted, or spun, by other machinery, by substituting a pair of conducting rollers instead of the bobbin and flyer, which shall conduct the sliver of material into a tin can below.
The descent of the heckles a, into their frames b, by the falling of the levers c, c, precludes the possibility of the fibres of the material operated upon being carried down under the machine by the points, as frequently happens in gill machines of the ordinary construction; and this mode of mounting the heckles and traversing them with the assistance of the guide bars q, q, and inclined planes r, r, allows the heckle points to be brought much nearer to the drawing rollers o, p, by means of the metal bars in which the heckle points or needles are set, falling below the centre of the endless chain e, e, as shown in [figs. 443.] and [444.], and thereby affords the means of preparing, drawing, and roving various qualities of flax, hemp, wool and other fibrous materials, particularly such as have a much shorter staple than any fibrous materials hitherto operated upon in gill machinery.