US141978A - Isvlproveiviemt in chucks - Google Patents

Description

T.' n. ALMo N D.

\ chucks. N0,` 141,978, PatentedAuvgust19J873.

w lll .si n-nmu fifi' PHO PR s THOMAS R. `ALMOND, OF FITOHBURG, MASSACHUSETTS.

IMPROVEMENT IN CHUCKS.

Specification forming part of Letters Patent No. 141,978, dated August 19, 1873 application filed July 2, 1873.

To att whom it may concern:

Be it known that I, THOMAS R. ALMOND, oi"

Fitchburg, in the county'of Worcester and State of Massachusetts, have invented an Improved Drill-Chuck, of which the following is a speciiioation:

Figure l is a side view of my improved drillchuck. Fig. 2 is a longitudinal central section of the same. Fig. 3 is a transverse section thereof on the line cla, Fig. l. Figs. 4 and 5 are side views of the chuck-jaws.

Similar letters of reference indicate corre spending parts in all the figures.

This invention relates to a new construction of a drill-chuck, having for its object to simplify, as much as possible, the arrangementof the parts and their operation, and thereby to increase the durability of the chuck. The invention principally consists in the use of a series of jaws, which are partly cylindrical i along their outer faces and concave on their gripin g or biting faces, and which are, on their outer faces, provided with spiral or bent grooves for the reception of pins that project into such grooves from the embracing-shell of the chuck. The lower ends of the jaws connect by a swivel-joint with a screw that enters the back of the shell, so that when said screw is turned the jaws will be longitudinally displaced within the shell,and during such displacement, by virtue of their spiral or bent grooves, they vwill be turned to bring their griping-faccs nearer to or farther away from the axis of the shell, and be thereby adjusted to the exact size of the rod or drill to be held. I prefer to use two pins in the shell for each jaw, and to have two spiral or bent grooves in each jaw, the two pins projecting at an angle toward each other of ninety degrees, more or less, so that such pins may also be used for exactly centering the jaws, by being screwed up more or less from one side or the other. I also prefer to so shape the spiral or bent grooves of such jaws that there is less curvature in them where the pins enter them for holding the jaws of a larger drill than where g the pins enter them for holding them in position for a smaller drill, so as to obtain a greater proportion of force for holding larger than for holding smaller drills. It will be observed that, by using these cylindrical jaws in con nection with a simple embracing-shell and adjusting-screw, all the complex devices hereto- -fore used for supporting and contracting the jaws with springs, wedges, Sie., are dispensed with, and the construction ofthe apparatus is materially simplified, while, at the same time, the most absolute degree of strength will be obtained.

ln the accompanying drawing, the letter A represents the shell of my improved chuck, having, at its lower or back end, a female screw-thread for the reception of a screw,\]3. On the upper part, the shell has on its inner side three or more partlyecylindrical recesses, which are parallel to its axis, and all equal in diameter to each other. These recesses are arranged for the reception of three or more jaws, (l G, which jaws are also cylindrical in outline, at least sufficiently so as to fully Jrit the said recesses, as shown in Fig. 3. Those parts of the jaws which face the axis of the shell are made concave, so that when the j aws are ,in the position shown in Fig. 3, with their concave parts all in continuous line, the space between them will be cylindrical, and will be the largest space that can bc formed betweenv them. The several jaws are grooved transversely at their lower ends, as shown at a in Figs. et and 5, to receive an inwardly-projecting iiange, b, that enters such grooves a from the recessed upper end of the screw B. Thus a connection is established between the screw and the jaws, as shown in Fig. 2, so that when said screw is turned it will cause the jaws to travel up and down with it. The outer sides of the jaws C C are provided each with one or more spiral or bent grooves, d, which are more clearly shown in Figs. et and 5. Into these grooves enter pins e c, which are screwed through the shell to enter said grooves, as shown in Fig. 3. When the jaws are lengthwise displacedby the motion of the screw B they will, owing to the spiral grooves and their connection with the pins c of the shell, also be turned all equally, because the grooves d are all alike, and when so turned will bring one of their edges nearer to, and the other farther away, from the axis of the shell A. Those edges of the jaws that are brought nearer toward the center of the shell, as indicated by dotted lines in Fig. 3, constitute the gripmgsurfaces of the chuck, and bear against the drill or vspindle introduced between them. The more, by turning the screws, the jaws are raisedTthat is to say, made to project out of the shell-the more will they be turned to iit and hold a smaller drill or spindle. The grooves d are, by preference, made straighter toward their upper ends, and inore spiral or bent at their lower parts, as is shown in Fig. 4, for the purpose of giving more power or purchase to the holding devices e c when the jaws are held for larger drills than when the lsaine are held in position for smaller drills, it being evident that a greater proportion of power is required for holding larger than for holding smaller pieces, and especially, also, in using them 5 and it being also evident that the more power is obtained the straighter the groove d. The pins e are screwed into the shell, as indicated. rlhe two pins pertaining to each jaw stand at an angle to each other or' about ninety degrees, more or less, as indicated in Fig. 3. Then the jaws are in the position shown by full lines in Fig. S-that is to say, for holding the largest-sized drill to which they are fitted-they can be exactly centered, if found not to be so, by turning one of the pins c more inward and relieving the other proportionately, and thereby slightly turning each For this reason, being able jaw in its socket.

to adjust the jaws and centering the saine, l prefer to use two pins, e, for each jaw, although I may produce a substantial and reliable chuck by having but one pin, e, for each jaw. It is also clear that, instead of grooving the jaws and having the pins c in the shell, substantially the saine results will be reached by grooving the inner faces of the shell-sockets, and providing projecting pins or feathers on the jaws; and I do not confine myself to either construction.

What I claim as my invention isl. The improved drill-chuck, consisting of a shell, A,partlycylindrical jaws C C, adjusting-screw B, and or' the pins c to tit the spiral grooves d, substantially as herein shown and described.

2. A spiral groove, d, for the jaw of a drillchuck, when made straighter toward the outer and more spira-l toward the inner end, sub- Witnesses:

A. V. BRrEsEN, F. V. BRIESEN.

Images