rectly on the bottom of the tunnel, or otherwise adapted to move thereon. On the frame is mounted a hollow shaft d, which is adapted to turn in appropriate boxes e, e, in the standards a, a, of the frame, so that it can turn freely and accurately. To the forward end of this hollow shaft is properly secured a cog-wheel f, the cogs of which are engaged by a pinion g, on a shaft h, provided at the other end with a cog-wheel i, which engages a worm j, on the transverse shaft k. Motion is communicated to this shaft k, from the driving power, in any convenient manner, for the purpose of giving a slow rotary motion to the wheel f, and hollow shaft d. The front face of the wheel f, is provided with flanches or arms 1, in which are hung two rocking-shafts m, m, which carry two sectors n, n; and as both are similar in construction and operation, the description of one of them will be sufficient. The sector n, is provided, at or near the ends, with two rotating discs o, o, mounted on appropriate arbors or spindles p, p, the axes of which are at an angle of 45° (more or less) with the axis of the rocking-shaft m. The arbor of each disc is fitted to turn freely, but accurately, in a tube q, the bore of which is eccentric to its outer periphery. This tube is in turn fitted to a box r, on the sector n, so that it can be turned and moved endwise therein, for the purpose of setting the disc as may be desired, and there secured in its place by a set-screw or other appropriate means.

The object of this mode of adjustment is to set the cutting edges of the two discs, so that one shall, in the vibrations of the sector, describe a different track from the other, in order that one may cut what the other does not; and it will be obvious, from the foregoing, that this adjustment can be readily effected by turning and sliding the excentric tubes in which the arbors of the discs turn. The inner ends of the two sectors are jointed to two connecting-rods 8, 8, (see fig. 3,) which extend into the hollow shaft d, and which are jointed at the other end to a cross-head t, on a sliding-rod u, which is appropriately guided in the hollow shaft as it receives a reciprocating motion by a connecting-rod v, from the arm w, of a rocking-shaft x. This shaft x, receives motion from the piston-rod y, of a steam-engine.

The arm of the rock-shaft x, which receives motion from the piston-rod of the engine, is in turn connected by a rod z, with a crank a1, on the shaft of a fly-wheel b1, to ease off the shocks which would otherwise be produced by the strokes of the engine. The feeding motion, for turning the wheel f which carries the cutting apparatus, can be derived in any

appropriate manner from the shaft of the fly-wheel, or from the rocking-shaft x.

From the foregoing it will be seen that, as the entire machine is advanced, the rotating cutters are brought in contact with the face of the rock or other hard substance to be cut; whilst the vibratory or reciprocating motion given to the sectors, in opposite directions, causes the cutting-edges of the discs to describe each a track from the centre of the wheel f, to the periphery and back again; each one describing an arc of a circle in the plane of the radii: and, as the wheel ƒ, is rotated with a slow motion, a series of cuts will be made by the peripheries of the cutters, which will be nearly in the direction of the radii, gradually shifting around the entire circle; and so on in succession,-the entire machine being moved forward, by any desired means, to keep the cutters against the face of the stone.

The patentee remarks, that he has described the machine. with two sectors and two rotating discs on each sector; but it will be obvious that it can be made with only one, or with more than two; and each sector with one or more discs. He does not wish to confine himself to the use of vibrating sectors for operating the discs, as it will be obvious that the discs can be connected with the periphery of a wheel or wheels having a continuous rotary motion imparted by cog-wheels, or their equivalents, by means of a shaft passing through the hollow shaft d, or by any other suitable mechanical means. And, as to the mode of rotating the cutting apparatus about the centre of the tunnel or other aperture, to make the series of cuts, it will be obvious that this can be done by a continuous or intermittent motion in one and the same direction, or by a reciprocating motion. And, finally, as to the progressive motion of the entire cutting apparatus in the direction of the axis of the tunnel or excavation, to keep the cutters against the face to be cut,-it can be continuous or intermittent; and may be communicated in various ways, such, for instance, as is shewn in fig. 1, where screws d1, d1, are made to work in standards e1, el, secured to the bottom of the tunnel, and acting against the end of the frame; or, by means of levers. acting against the frame and abutting against some solid part of the tunnel, the whole machine may be pushed bodily forward.

The patentee claims the method herein shewn and described, or any mere modification thereof, for applying rotating discs or cutting-edges for boring or excavating tunnels and other apertures in rock or other hard substances, by

causing the said cutters or rotating discs, or sets of rotating discs, to describe circles from the centre, or near the centre, to the periphery of the tunnel or other excavation, in combination with a motion or motions around the centre of the said tunnel, to cause the said cutter or cutters to act in succession on the entire surface to be cut away.

To JOSEPH HENRY TUCK, of Pall Mall, engineer, for improvements in stuffing-boxes, and in packing to be used in stuffing-boxes, bearings, pistons, and valves.-[Sealed 14th October, 1852.]

THE object of this invention is to make an enduring packing for piston-rods, pistons, valves, stuffing-boxes, bearings, and other rubbing surfaces. Instead of using hemp or metal packing, as heretofore, the patentee constructs a packing, composed partly of yielding and partly of rigid substances. The elastic part of the packing is, by preference, composed of rolls or folds of canvas, coated with India-rubber; and in the tubes or ribs of this stuffing, strands or blocks of India-rubber may be inserted. The hard substances, used in conjunction therewith are segmental or other suitably-shaped pieces of wood or metal, which are intended to lie or work in contact with the metallic surface, whether moving or stationary (as the case may be) against which the packing is intended to bear; the segmental or other shaped pieces being kept up to the rubbing surface by the elastic pressure of the yielding substance. In order to ensure the proper action of this substance in glands or stuffing-boxes, the interior of the gland is made conical, or in the stuffing-box a conical filling piece is inserted, which will answer the same purpose. By this means the pressure downwards of the gland or cover of the box, will ensure the proper binding of the packing around the pistonrod. In some cases a half-round annular groove is turned in the gland or stuffing-box, to act as a second oil cup, and thereby prevent the waste of the oil. The segmental pieces may be put together, so as to present a continuous hard surface to the piston-rod, in the form of a tube (the pieces being put together as rings, forming break-joints, and locking the one ring into the other, to prevent the independent movement of any one piece); or, between the rings, the elastic material may be interposed, so as to present a varied packing surface of alternate rings of flexible or elastic, combined with rigid or unyielding, materials.

VOL. XLIII.

B

In Plate II., fig. 1, represents a vertical section of a stuffing-box, with its packing, constructed and arranged uponthe improved plan. a, is the stuffing-box; b, the gland; c, the bottom bush of the ordinary stuffing-box; d, is a lining, constructed in the form of the frustrum of a cone, and formed, by preference, of wood or other rigid material, which is a bad conductor of heat. This lining is composed of any given number of parts, which, when assembled together, form the frustrum of a cone, as shewn in the figure. e, is the improved elastic packing, or other ordinary packing may be used, if preferred; f, is the piston-rod or rubbing surface, against which the packing is forced by screwing down the gland b. It will be readily seen that a slight pressure on the gland b, will force the soft or elastic packing down, and compress it inside the cone d, which, being of an inclined or wedge form, thereby forces the packing e, directly against the rod f, and keeps it steam-tight. Fig. 2, is a vertical section, shewing a modification of the above: the parts a, b, c, d, e, and ƒ, are the same as in fig. 1. g, g, are rings of metal, or other suitable material, cut into two or more parts, and placed between the rings or layers of soft packing; thus presenting a compound surface to the rod f, or other sliding part. Fig. 3, represents a modification of fig. 2: in this instance, however, the cone or lining d, is dispensed with. In fig. 3, the hard rings consist of four parts or two rings of triangular section, placed together base to base; thereby forming one ring. In fig. 4, a series of rings, each consisting of two or more parts, are shewn as placed one upon the other, so that a solid surface is presented to the rod or portion liable to friction. Behind these rings, which form a cylinder or cone, as the case may be, according to the shape of the backs of the rings, soft packing is applied, which, when pressed down, forces the hard rings g, g, against the piston-rod or other moveable rubbing surfaces. In fig. 5, a double series of rings, each of two or more parts, which are of a triangular section, are placed upon each other: the rings h, h, are forced back against the inside of the stuffing, and the rings g, g, are forced against the rod or moving surface, by being pressed from above. j,j, are rings of soft packing, to fill up the space at the back of the rings 9, 9.

Fig. 6, is a vertical section, and fig. 7, a plan view, of another improvement in stuffing-boxes, the object of which is to admit of the lining or stuffing being removed from the box with greater facility, and in a more convenient manner than is usually the case. The stuffing-box is lined with a metallic

cup or box k, k, which is so made and adapted to the stuffingbox that it may be drawn out of the box, and bring with it the whole of the packing which is placed in the cup, box, or lining k, k. This cup or lining is made of two or more parts, and the upper flange thereof rests upon the flange of the stuffing-box a. The packing is shewn in the drawing as being made upon the principle already described, and consists of a cone d, composed of wood or other bad conductor of heat, combined with soft elastic packing e, which is, or may be, compressed against the rod f, by screwing down the gland b. The cup or lining k, and packing contained therein, may be drawn up out of the stuffing-box by means of the screws 1, 1,-the shoulders of which bear upon the plate m, which lies on the flange of the stuffing-box a. A jam-nut n, is provided for securing the screws at any point where the cup or lining k, has been raised high enough. As the cup or lining k, is constructed in two or more sections, it will be evident that, when it has been raised out of the stuffing-box, its parts may be separated and removed; thus leaving the packing exposed and entire upon the rod or trunnion, so that it be adjusted, repaired, or removed, as may be required. It is stated, that any of the plans above shewn and described, for making a packing or lining for stuffing-boxes, may be adapted to, and employed in connection with, the improvement just described, with relation to figs. 6, and 7; or any ordinary packing may be used,-the object of this improvement merely being to enable the packing to be lifted or drawn out of the stuffing-box with facility when it is required to be repaired, adjusted, examined, or removed.

may

In figs. 8, 9, 10, 11, and 12, several methods of adapting the improved system of compound packing to D-slide valves is shewn. Fig. 8, represents a plan view of the packing suitable for a D-slide valve, with the improvements adapted thereto. Fig. 9, is a view of the packing as seen from the inside; and fig. 9a, is a cross section of the same, taken in the line 1, 2, of fig. 9.

The slide or moving surface, is shewn at o. The hard packing p, is kept against the slide, or moving surface, by the soft or elastic packing 4, at back, which is pressed forward by the metal jacket r. The hard packing consists of an entire metal surface presented to the slide, and formed of a series of flat-linked or mortice-jointed chains, lying close against each other, and rivetted throughout, and kept up to its proper position against the slide by the soft packing and jacket r, at the back and ends.