The fly-wheel is loose upon the shaft, which is attached to, or detached from, the fly-wheel, by a friction-clutch p, which enters the conical interior of the drum n, and which is moved by the levers q q; r is a double-threaded screw, by which the sliding carnage is advanced; it works in a nut s, which turns in a bearing t; to this nut are attached the rachet-wheel v and the cogwheel w; x a pinion acting upon w, and turned by the handle y, and only used to bring the blocks under the cutters for the first cut, after which the carriage is advanced by the machine in the following manner: - Upon the shaft m is an eccentric l, which acts upon a roller 2 in a vertical lever 3, to the lower end of which is jointed a horizontal bar 4, which has a tooth acting upon the teeth of the ratchet-wheel, so that at each revolution of the axis the eccentric thrusting out the upper end of the lever 3, moves in an opposite direction the ratchet-wheel v, which, by means of the nut s, turns the screw, and advances the sliding carriage, so as to bring a fresh portion of the block under the cutters.
When the whole length of the mortise is cut, the advance of the carriage further is prevented as follows:- The extremity of the bar 4 is prolonged beyond the ratchet-wheel, and rests upon the lever 5, which turns upon a pin in one of the upright columns of the frame. The lever 5 is supported by the curved end of the lever 6, the other end of which rests upon an adjustable slide 7, which is screwed to the sliding carriage, and which is so fixed, that when the mortise is completed, the long arm of the lever 6 is no longer supported by the slide; the long arm of the lever consequently descends, and, by its descent, raises the lever 5, which lifts the bar 4 clear of the teeth of the ratchet-wheel. Fig. 2 is a side elevation of the shaping machine; a is a large circular rim, or chuck, firmly keyed upon the shaft; b a similar chuck; c (which cannot be shown in the drawing) is placed upon the shaft behind a. This chuck is not made fast, but may be set upon the shaft at any required distance from a to suit the different sizes of the blocks; d d are stay bolts passing through the chucks a and c, and having nuts at the back of c to retain it at the requisite distance from a; e e are the blocks which are to be shaped; they are retained between the two chucks a and c, as follows: f f are a number of short maundrils, set in the chuck a, and each carrying on the farther end a small cross, the extremities of which have two sharp steel rings; in the chuck c is a screw, opposite to, and concentric with, the maundrils f f; the inner end of these screws having a sharp steel ring loosely fitted upon them.
Each block, in the operation of boring the holes previous to passing to the mortising machine, has had the line of its axis determined, by the marks of two steel rings impressed on one end, and of a single ring upon the other. The marks of the two rings are applied to the steel ring on the cross, and the ring on the screw is advanced by the screw to the single mark on the other end of the block; g is a slide rest, supported upon the bed A, and attached to the radial bar j, which turns upon a centre directly beneath the line of the axis of the shaft b; k is the bar carrying the cutter l, and sliding in a mortise; m a steel spindle, passing through a socket in k, and having a small horizontal roller n fitted upon its lower end; o one of two pillars supporting two curved bars p q, called shapes; the curve on one bar determining the shape of the faces of the blocks, and that of the other bar the shapes of the sides of the blocks, r is a lever by which the cutter bar is moved along its mortise, so as to cause the roller n to press against one of the shapes p or q; t is a bar attached to the slide rest, by which the rest is made to traverse the bed h, describing a portion of a circle of which the pivot of the radial bar is the centre.
The operation of the machine is as follows: the chucks being filled with a number of blocks corresponding to the number of maundrils, the chucks are set in motion by a strap from the engine passing round the drum t keyed upon the shaft b. The cutter l being previously adjusted to the proper distance, the attendant holding the bar s in his right hand, causes the slide rest slowly to traverse the bed h, whilst, by the lever r, held in his left hand, he keeps the roller n in contact with the shape p or q, and consequently causes the cutter f to describe a curve similar to that of the shape; and that face of the blocks which is exposed to the cutter revolving with extreme rapidity against the cutter, is cut to a corresponding shape. When the first side is completed, the blocks and the chucks are stopped, and the blocks are turned one-fourth round, so as to present the next side to the cutter. This is effected by the following means: on the outer end of each maundril is fixed a worm wheel v, upon which an endless screw upon the outer end of the spindle w acts; upon the other end of each spindle is fixed a bevilled pinion y, gearing with a bevilled wheel x, fitted loose upon the axis.
When it is required to turn the block, the wheel x is locked to the frame by a catch pull (not shown) and the attendant turns round the chucks a and c four times, and the bevilled pinions revolving round the wheel x cause the spindles on which the endless screw is cut to turn the worm wheels one-quarter round. The roller n is then by a simple movement pushed down, so as to act against the lower shape; the chucks are again set in motion, and the slide rest being made to traverse back over the bed, the second face is shaped, and the operation is repeated for the other two sides.