Another chuck of self centering design, has likewise appeared in the periodical above named, into which it appears to have been copied from an American paper.
The accompanying engravings illustrate some improvements in the arrangement of chucks which have been recently patented in this country, the inventors being Messrs. Smith and Haight, both of New York, U.S. The first part of the invention refers to an arrangement of adjustable chuck, by means of which tools and other articles of different diameters may be held firmly in the jaws of the chuck. [Fig. 31B] is a longitudinal view of the chuck, partly in section. The spindle, a, is fitted so that it may be inserted tightly in the mandrel of the lathe. On the front end of the spindle is a conical screw on which is fitted the cap, b; this part is formed with an opening at the front end, having three longitudinal slots in it. In each of these slots an adjustable jaw, c, is fitted, the inner part of which is threaded with a female screw, to fit the conical screw on the spindle, a. An outer casing d, encloses the front part of the chuck, and behind this is fitted a loose collar, which is screwed into the casing d, so as to connect the parts firmly together. By turning the cap, b, with the casing, d, and collar, in one direction, the jaws, c, are moved forward and project out through the openings, and they may thus be adjusted to grip a tool or other article of small diameter. The opposite motion of the cap causes the jaws to recede, and in this way they may be adjusted to grasp articles of different diameters.
Fig. 31B.
Another arrangement of the adjustable chuck is shown in [Fig. 31C], which is a front view, and [Fig. 31D], a longitudinal section of the same. A, is the body of the chuck, the front part of which is formed with a rim or flange, in which are three radial recesses having fitted therein the sliding jaws, B. In the rear of each jaw is a bearing, in which is fitted a pin carrying a small lever, C, the front end of which is rounded, as shown in the section, and enters a slot made in the jaw, B; so that when the levers are moved outwards they cause the jaws to contract or move towards the centre. The back part of the body, A, of the chuck is threaded, and on this part is fitted a collar, D, and in front of this is a sliding collar, E, which is connected to the collar, D, by means of a pin which enters a groove formed in the latter. The sliding collar is prevented from turning round on the body, A, by means of a feather, which works in a longitudinal groove formed in the inner circumference of the collar. Three inclined planes, F, are formed on the periphery of the collar, E, which extend to the backward ends of the levers, C, so that by moving the collar to and fro, the jaws, B, are caused to contract or expand, according to the size of the article to be grasped. A short cylindrical block, G, made of a conical figure internally is fitted loosely within the chuck, A, and serves to centre the end of a drill or other short article, but may be removed when it is desired to pass a rod or other article through the body of the chuck. To provide for the easy turning of the collar, D, it is shown as fitted with a hand wheel, H. With this arrangement of the several parts, the jaws of the chuck readily adapt themselves to drill or bit shanks as well as to articles of parallel form, or of a tapered or irregular figure.
Fig. 31C.
Fig. 31D.