Cake or Plug.—The manufacture of "cake" or "plug" is little carried on in this country, as the Excise laws exclude the use of sweetening matters, except when carried on in bond. The process is sufficiently simple. Virginian leaf, with or without the addition of flavourings, is sweated for a day or two, to deepen the colour, worked into a soft mass, and next placed in moulds, and subjected to sufficient pressure to ensure the cohesion of the mass. Each cake is then separately wrapped in perfect leaf, and passes through a series of moulds, each smaller than the last, and under increasing pressure in steam-jacketed cupboard-presses, of which there are many forms. The combined effect of the heat and pressure is to thoroughly impregnate the whole mass with the natural juices of the leaf and the flavouring (if any has been used), and to produce a rich dark colour.
A machine for turning out plug-tobacco in ribbons, made by the McGowan Pump Co., New York, is shown in Fig. 1005. The tobacco is first weighed out in the proper quantities, and spread in a box placed in spaces in a heavy iron table a. When the latter is filled, it is passed to and fro under the heavy iron wheels b, which are loose on the shaft, and which can be adjusted to exert any desired pressure. Twice passing through suffices. The ribbon is made in lengths of 10 ft., and either 5.1 in. or 2,-} in. wide, as desired.
Roll or Twist.—Roll- or twist-tobacco is made by spinning the leaf into a rope, and then subjecting it to hot pressure. Until recently, the spinning was performed by hand, much after the manner of ordinary rope-making by hand. But this slow process is now superseded by a machine made by Robinson and Andrew, of. Stockport ; it is spoken of in very favourable terms by English manufacturers, and received a diploma of merit at the Philadelphia Exhibition. The machine consists of a combination of 3 rollers, whose surfaces are made of segments, to which lateral to-and fro motions are given by cams attached to the stands on which the axles of the rollers rotate. The tobacco occupies the central space between the 3 rollers, and it is carried through the machine by the lateral to-and-fro motions given to the segments. The fillers and wrappers are laid on a table joined to the machine. The filler is placed in the cover, and they pass together between the rollers, whose action twists and compresses the tobacco into a roll ; this is carried forward and wound on a bobbin, revolving in an open frame, and provided with a guide for equalizing the distribution of the tobacco.
The machine is shown in Figs. 1006 (elevation), 1007 (plan), and 1008 (end view). The tobacco is laid on the table a, provided with a rib n, on which the sliding rest b is free to move to and fro ; c d are the two lower segmental rollers, the axles of which revolve in stationary bearings ; e is the top roller, the axle of which revolves in sliding bearings, fitting in the swing-frame f, and each acted upon by a spring o, pressing on a piu communicating with the bearing, and putting an elastic pressure on the tobacco.
Each segment-roller consists of an axle with four segments, best shown in Figs. 1009 and 1010. The outer shell of the 'segments is made of bard wood, fitting an inner shell of malleable cast-iron, the projections on which suit moves on the cast iron axle. The segments of the rollers c d are moved laterally to and fro by the wedge-shaped cams p q r s, fixed to the bearings of the roller-axles ; and the segments of the roller e are moved in the same manner by cams t u, fixed to the swing-frame f. The
tobacco occupies the central space between the 3 rollers, and the cams p r t move the segments in the direction of the arrow where they touch the tobacco, while the cams q s u move them back. After the tobacco has passed beyond the segment-rollers, it goes through the hollow trunnion of the open frame g, in which the bobbin h revolves ; the other trun nion of the frame g is provided with fast and loose pulleys, by which the whole machine is driven. To this trunnion, are also fixed an ordinary friction-break pulley, and a grooved pulley, around which latter passes a band for driving the pulley on the axle of the bobbin h. To the other end of the axle of the bobbin, is fixed a pinion, which, by means of a toothed chain, gives motion to another pinion fixed to the double sorew i ; this double screw gives a traversing to-and-fro motion to the guide j, for distributing the tobacco evenly on the bobbin, by means of a swivel T-headed stud, connected with the guide, and taking into the thread of the double screw. The guide is provided with two horizontal grooved rollers, between which the tobacco passes, and with two other rollers to guide the tobacco on to the bobbin.
Rotary motion is communicated to the segment-rollers c d e as follows :—To the hollow trunnion of the open frame g, is affixed a pinion, which drives the wheel k, on the same shaft as the cbange-pinion that drives the wheel gearing into the pinions on the axles of the rollers c and d, and one of which pinions gears into the intermediate pinion i, which drives the pinions on the axle of the roller e. The-driving strap is held upon the fast pulley by a drop-catch acting on a weighted lever, one arm of which is connected by a link to the lower end of a strap fork-lever. When it is requisite to stop the machine, the attendant kicks the point of a catch off the end of the lever, which is then raised by the weight, and so moves the driving-strap from the fast to the loose pulley, the stop page being virtually instantaneous. The mode of working is as follows :—The spinner and assistants stand at opposite Bides of the table ; the fillers and wrappers being placed on the table, one assistant spreads out the wrapper and pushes the end towards the filler, which the spinner supplies and bolds against the sliding rest b; the rotary motion of the segment-rollers c d e twists the tobacco, and causes the wrapper to be wound over the filler, and the rest b, being movable, enables the spinner to regulate its position according to the quantity and quality of the filler and wrapper. The lateral motion of the segment-rollers passes the roll towards the bobbin, on which it is wound, as described. The combined rotary and traversing motions of the rollers consolidate the tobacco, and put the desired face upon the twist. The roller e is supported in a swing frame, which is lifted off the tobacco when starting the machine. When the machine is at work, the swing-frame is held down by the stud m (Fig. 1006). The figures represent a machine suitable for mauufac turing Limerick roll; for pigtail and other small descriptions, it is necessary to reduce the diameter of one or more of the seg. m ent-rol lers.