Патент USA US2261899код для вставки
Nov. 4; 19.41. F, J, BECHERPr 2,261,899 COLLET Filed Api‘il 6, 19:59 INVEN‘ILOR FRED d. BECHERT ATTORNEY-5 . Patented Nov. 4, 1941 I 2,261,899 ' UNITED STATES PATENTI OFFICE-‘l ~ ' COLLETV Fred J. Bech'ert,’ Stamford, Conn.,'a'ssignor to The ' New Britain Machine Company, New Britain, Conn, a corporation of Connecticut ' " Application April 6, 1939, Serial No. 266,259 2 Claims. (01. 279-46) 7’ My invention relates to a chucking means and more particularly to an improved form of collet and, pad. ‘ jaws or pads 9-9. In the form shown each jaw has a cylindrical seating surface I0 extending from front to rear, and each pad _9 has a‘ corre . It is now common practice to insert false jaws or pads in a collet and the commonest method sponding cylindrical seating surface II, extending for holding the pads in place is by means of radial movement of the pads in the jaws. ‘Each Jaw has a generally radially outwardly extending abutment surface‘or shoulder I2 and each pad screws extending radially through the collet jaws and into the pads. In order to change pads when from front to rear, so as to limit the outward so held in place it is necessary to move the collet at the rear has a corresponding surface or outlof its seat in order to render the screws ac 10 shoulder I3 to abut the surface; I2. , These sur cessible. Other means for holding pads which have been proposed involve the use of screws or other holding means, accessible from the front of the collet to avoid the necessity of backing the collet out of its seat for pad changing. Devices of that sort are subject to the objection that the holding screws may be accidentally backed out and lost or in some cases interfere with the tools faces I2-—,I3 are preferably slightly inclined so that when the pad, 9 is drawn toward, the right the inclined surfaces ;I2-I3 tend to urge or cam the pads radially outwardly into engagement with the jaws» ' , , ‘ . - ‘ The pads are secured in place by improved means interposed between the jaws and pads ac cessible from the front and held by the jaws and pads themselves against loss or dislodgment when It is an object of ,my invention to overcome the 20 the parts are assembled. In the form illustrated above di?iculties and, in general, to provide an each jaw has a generally radially outwardly ex improved form of collet and pad. , tending ?ange or- part I4,v which may?t into a working adjacent to the collet. ' A more speci?c object is to provide a collet counterbore I5 in the front of the jaws. There and pad with means for holding the latter in is a space I6 between the rear of the part I4 and place and positively preventing the same from 25 the bottom of the counterbore I 5, so that the pad working loose when the pads are assembled with may be moved toward the left to disengage sur the collet jaws. faces I2—I3 so the pads may be dropped radially Another object is' to provide an improved form inwardly for removal. In the preferred form, one » of collet and pads, relatively simple and cheap to of the jaw and pad members carries means en manufacture and effective in use. ' 30 gageable with the other and prevented from dis Other objects and various features of inven lodgment by engagement with one of the parts. tion will be hereinafter pointed out or will be As illustrated, each jaw is provided with one or come apparent to those skilled in the art. more threaded bores I'I, preferably extending In the drawings which show, for illustrative generally longitudinally inwardly. A threaded purposes only, a preferred form of the inven 35 member I8, preferably in theform of a so called tion headless set screw, is threaded into the bore I‘! Fig. 1 is a side view of a collet, parts being and extends outwardly into engagement with the shown in central vertical section to illustrate fea rear portion of the ?ange part I4. The latter tures of the invention; and preferably has a generally countersunk recess I9 Fig. 2 is a fragmentary front View of the collet 40 in the rear face thereof and the screw I8 is pref and other parts shown in Fig. 1. erably chamfered off for engagement with the The invention will be described as embodied in upper portion of the countersink I9, so that when a draw-back type of collet, though in its broader the screw I8 is backed out, that is, moved toward ‘ aspects the invention is not so limited. The collet the right, the entire pad will be urged toward 45 may be carried by means such as a rotating the right and the chamfered end of the set screw spindle 5, having a spindle nose 6 with a rear will also urge the pad radially outward at the wardly inclined or conical collet seat 1.‘ The col front end. The member not carrying the set let includes a plurality of jaws 8-8, three being screw, in this case the pad, is provided with an shown, which jaws have outer surfaces to ?t the opening, say in the form of a hole 20, in general seat ‘I, so that when the collet is drawn axially 50 alignment with the set screw I8, and the latter rearwardly or to the left as viewed in Fig. 1 the is provided with a depressed wrench socket 2I jaws will move in radially, to grip the bar stock for receiving a wrench inserted through the hole or other work, all as is now common practice and 20, whereby the screw may be actuated. will be understood. When it is desired to remove the pad a wrench The collet jaws 8-8 are provided with false is inserted and the screw I8 turned into the 2,261,899 bore l1, after which the pad may be moved it is to be understood that various changes may toward the left to disengage the surfaces l2-l3 be made within the scope of the invention as and permit the pad to drop radially inwardly de?ned in the appended claims. I claim: for removal. A new pad may then be applied by ?rst engaging the surfaces [2-43 and then by means of a wrench backing the set screw [8 outwardly in its bore ll, so as to cause engage ment of the forward end of the screw with the rear portion of the ?ange part Hi. It will be .1. A collet having a plurality of spring jaws including tapered jaw members and spring legs rearwardly of said jaws, removable pads for said jaw members, said jaw members each having a generally radially extending undercut abutment seen that so long as the pads are in place on 10 surface toward the rear thereof, the inner diame the jaws the screws l8 cannot become dislodged. 4 ter of each of said jaw members from said abut ' ment surface to the rear end of said jaw mem and lost nor can they project axially outwardly beyond the face of the jaws. Therefore, there’ lbers and the inner diameter of said spring legs being at least as great as the inner diameter of is no possibility of losing the screws nor pos sibility of their interference with. tools-acting 15 the jawfmember at the base of said abutment, said pads having abutments to fit said abutment adjacent to the front of the collet. Instead of surfaces on said jaws, and means for holding employing the countersink IS the rear, part of said pads in place on said jaws. the flange may be inclined radially outwardly 2. A collet having a plurality of spring J'aws and rearwardly and the screw [8 may be screwed into a bore inclined to the axis of the collet, so 20 including tapered jaw members and spring legs rearwardly? of~said jaws, removable pads'for-said as to urge the pad toward ‘the right andiradially jaw‘ members, said jaw members each having a outwardly, as will be understood. ' ‘By reason of my invention the manufacture of generally radially extending undercut abutment‘ the'jaws and pads is somewhat simpli?ed. The only surfaces, with the possible exception of the surfaces .|2—l3 and the stock gripping surfaces, which‘ need grinding 'or other accurate ?nishing are‘ the surfaces l0—-| l, and those'surfacesare surface toward the-'rear‘thereof, the inner diame ter of each of said jaw members from said abut-' ment surface to the rear end of said jaw mem-‘ hers and the inner diameter of said ‘spring legs being at least as great as the inner diameter of the jaw ‘member at the, base of said abutment, of a uniformdiameter and continuous from end tofend, that is to say, ‘the ?nishing of the sur 25 30 each said'jaw member having a longitudinally face III ‘is a simple bore grinding operation‘ and the. ?nishing of the surface H is an equally extending surface thereon forwardly of said un: of each ‘jaw from' the surface l2 to the rear face yon-said jaw member, each said pad having, of the? jaw " member and the inside diameter an outwardly directed‘ ?ange thereon at the front,’ and a screw threaded in each jaw member and engaging the rear of said ?ange to hold'the dercut abutment surface,- each said pad having an'abutment to engage said abutment‘surface simple“ operation; The grinding or ?nishing of one-said jaw member and‘ having a longitudinally the surface 12 on each jaw is greatly facilitated by reason of the fact that the inside diameter 35 extending surface to ?t the corresponding sur-' of- the spring leg carrying the jaw are at least as great as the inside diameter of the jaw mem ber at the base of the abutment surface I2._ ' While the invention has been described in con siderable detail and a preferred form'illustrated, 40 pad in place on the said jaw‘ member. ' FRED J. BECHERT.