US2457030A

US2457030A - Chuck

Info

Publication number: US2457030A
Application number: US615634A
Authority: US
Inventors: Bugatti Ettore
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-05-16
Filing date: 1945-09-11
Publication date: 1948-12-21
Anticipated expiration: 1965-12-21
Also published as: FR992146A; GB593503A

Description

De.21,194s. Y E. BUGATTI 2,457,030..

cHucKI Filed sept. 11. 1945"Y Patented Dec. 21, 1948 UNITED .STATES PATENT `OFFICE.

Application-September 11, 1945, Serial No. 615,634. In France May 16, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires May 16, 1964 `8 Claims.

The chucks utilized for holding 'the work to be .turned on a lathe must have their jaws rigorously centered .on the axis lof the headstock, and keep this property even after a prolonged use.

The influence ci the vvarious "plays resulting either from construction or from wear `and capable of alterating centering is too knownfor it being necessary to set forth the effects thereof.

.In particular, the rim` which is fa member com mon to `all Vtypes of chucks `(said rim having, on cneace, Aa bevel zgea-r vmeshing with the conical control pinions and, on the uother face., a spiral groove -or scroll the rotation yof which causes aXial shifting of the jaws) turns within a hollow cylinder constituting the casing oit the chuck,'with clearance either on its outer'periphery or on its inner periphery.

Now, it is known .that concentricity ci vjaws is strictly dependent -on the holding of said rim, the offsetting ci which causes a corresponding shifting of the jaws. Itis then indispensable to provide for the rim a centering with a minimum play either inside the casing or 'on the central male lpart, or hub, of said casing.

In usual practice, .one -is limited in this way by the fact that the rim must turn very freely in its housing or on the hub and by other oonsiderations inherent in the method oi construc tion of chucks (risk yof jamming of jaws, etc).

This invention has for an object to provide means whereby toothed .rim of chucks `are centered without play while ythey may rotate freely. -A further object is to provide means which compensate automatically for play resulting from wear, and contribute to keep concentricity of chucks lafter a .long use.

According to my invention, a chuck rim is mounted with an amount of play `in its outer casing, and `between the inner bore of the rim Aand the hub which carries said rim, an automatic or manually adjustable device fior taking up play is provided. Said device, constituted essentially by an expansible circular bearing automatically centers the rim on the .hub and consequently on the axis Aof the chuck. .f

4in a nrst advantageous embodiment .of-this invention, the expansible bearing is constituted by a pair of concentrical conical rings' at Aleast one of which, is .split yand ladapted to expand when the other is axially moved by a spring orotfher similar member.

In another embodiment, the hub of the chuck or else the bore of the vrim is conical. In this case, there is provided one conical ringmade of independent segments.

Finally, Athe .same result may ybe obtained `by using la row vof balls or possibly conical rollers resting on Va conical ballwace on the ria-n, and on a cylindrical balia-ace cont-ered on the hub; the latter `balL-race may .be -axially shifted either through .a thread on the hub, or by a spring. Conversely, 'a conical lball-.race integral with the hub may .be combined with a cylindrical 'ball-race provided in the rim. The latter ball-.race is stationary when that on the hub is movable, or movable when the latter is stationary.

The following description with reference to the appended drawings given solely by way of eX ample will show `how this invention may be carried out.

Fig. l is a partial Vcross section of a chuck according to this invention.

Fig. 2'show-s a detail according to another em- .bod-intent of 'this invention.

1li-g3 shows ya modication of the device shown on Fig. 2.

Fig.. 4, correlated with Fig. 3,'sl1cws a detail common to Figs. Zand 3.

Fig. 5 shows, as a modification, another embodiment of this invention.

Fig. 6 shows a device derived from that shown on Fig. 5.

The -body l of the chuck represented on Fig. l. by Way of illustration constitutes the casing for said chuck .and confines .all the usual component members, the rim 2 alone being represented. Control pinions meshing with the bevel gearing -face 3 of -r-im 2, 4and the jaws sliding in suitable grooves provided v.in the bottom 4.- lof casing l are not represented. It will be assumed that the cross .section .shown on Fig. 1 vhas been made by a plane containing `neither the `pinion axis nor that of the jaws.

.A Acover .5, the threaded portion libia ci which is screwed on the shaft oi the headstock is centered in. the bore 6 oi casing i, and both members are `united by means of screws not shown on the figure. An amount of play is provided between the outer surface l of rim i? and the inner surface'f oi easing i; said surfaces must not, in any case, cc'me'nto contact with one another.

Rim :v2 bears on the face lll of bottom 4 through its .tace 9 which has a spiral or scroll gearing corresponding to that ofthe jaws, so as to leave a normal clearance between the teeth of face 3 and those oi the conical control pinions.

A ring H, which is outwardly conical, is borne on hub l2 of casing l. Said. ring il comprises, for the best, aseries of seg-ments in order to .preclude clearance between its bore andthe outer surface of hub I2; said clearance would be unavoidable if ring II was made oi one part.

An inwardly conical ring I3 is fitted on ring II and tends to be expanded by the thrust of a spring Ill.

Spring ill is backed by the bottom 4 of casing I, ring I3 reacting against the spring thrust by abutting :against the hub I5 of cover 5. Splits |30 which partly out the ring I3, give the latter sufficient resiliency to cause the male and female cones, when eng-aged, slightly to squeeze ring I3 in the bore IE5 of rim 2. Rim 2 thus turns without play on ring I3, the close fit being determined by the strength oi spring ld and th-e apex angle of conical rings II and I3.

Rim il wears where there is a friction, that is to say in bore I6 and on the outside of ring I3, rand wear is automatically compensated for by a corresponding axial shifting of ring I I.

In the example shown on Fig. 2, a single ring I'I, which is inwardly conical, is used; said ring, resting on a conical surface I8 on the hub I2 of casing I, tends to expand and to lill the bore I6 of rim 2. rIhis r-esult is obtained owing to the fact 'that ring I'I is comprised of a series of segments, and is continuously urged by la spring I9 backed by hub I5 of -cover 5. Said spring I9 may be shaped as a thin steel ring having undulatons (Fig. 4). The various segments such as IIa and Ilb which constitute ring I I have a straight or an oblique cut; in the latter case, the sli-ding conditions in bore I6 of rim 2 when the latter turns, are improved.

In order to prevent ring I'I from being driven round by rim 2 pins 2l set in hub I2 are inserted in each gap such as 28 which separate the segments of ring I'I.

In the modification shown on Fig. 3, ring 22 is conical outwardly and tends to fill the inner cone 23 of rim 2. Like ring I'i, ring 22 is constituted by a series of segments, this lallowing of removing clearance both along hub I2 and rim 2. The device acts exactly like that of Fig. 2.

In the embo-diment shown on Fig, 5, the ring 2li made of special steel is forced into a housing 25 provided in the centre of rim 2. The diameter of the bore 26 of rim 2 is appreciably greater than the diameter of part 21 of hub I2 which faces said bore.

Rim 2 is centered through a row of balls 28 rolling both in the inner cone 290i ring 24 and on the inner ring Si), itself screwed on hub I2. When mounting the chuck, it is only necessary to screw ring 3c by m-eans of castellations 3| until there is no more play between balls 28 and the two ballraces 29 and 3U; however care should be taken in order that rim 2 may still turn freely.

The play resulting from wear is periodically removed; to this end, the chuck cover 5 is disassembled and ring 33 is screwed by the required` amount.

The same result is automatically obtained with the device shown on Fig. 6, in which a spring 32', similar to above'mentioned springs I 4 or I9, allows of compensating for Wear by constantly pushing race 33 in which roll balls 26.

The embodiment shown on Figs. 5 and 6 is based on the use ci balls. The latter may advantageously be replaced by conical rollers rolling on rings similar to rings 2li and 30 or 33. In this order of idea, it is advisable to use commercial bearings of the Timken kind, the outer ring of which would be forced into rim 2 while the inner ring would slide on hub I2, being urged by a threaded washer or a spring. y

r ment member.

It will be obvious that minor alterations may be brought about in the foregoing embodiments, especially by using equivalent technical means, without departing from the spirit of the appended claims.

What I claim is:

1. In a chuck of the type described, the combination of a chuck body having a hub; a jaw control ring loosely mounted on said hub for rotation thereon; and radially 'expansible means interposed between said hub and the inner periphery of said ring for bearing said ring from said hub and taking up clearance therebetween.

2. In a chuck of the type described, the combination vof a chuck body having a hub; a jaw control ring losely mounted on said hub for rotation thereon; a radially expansible means, adapted to be operated by axial thrust thereon, interposed between said hub and the inner periphery of said ring, for bearing said ring from said hub and taking up clearance therebetween; and resilient means backed from said chuck body, for axially pushing the expansible means. f

3. In a chuck of the type described, thecombination of a chuck body having a hub; a ring on said hub, having a close fit therewith, the outer periphery thereof being conical; a split ring with a cylindrical outer periphery and an inner conical periphery on the first ring; a jaw control ring'revolubly borne with a close fit on said split ring; and resilient means for urging the rst two rings towards one another in axial direction.

4. In. a chuck of the type described, the combination of a chuck body having a hub; a ring on said hub, having a close it therewith, the outer periphery thereof being conical; a split ring with a cylindrical outer periphery and an inner conical periphery on the first ring; a jaw control ring revolubly borne wth a close t on said split ring; means on said hub providing abutments for each one of the rst two rings, on either side of said rings, one of said abutments being resilient and one of said abutments being adjustable.

5. In a chuck of the type described, the combination of a chuck body having a hub Witha stationary abutment thereon; a ring on said hub, on one side of said abutment, having a close nt with said hub; a split ring with a cylindrical outer periphery and an inner conical periphery. on the first ring; a jaw control ring revolubly borne on the split ring; resilient means operatively interposed between one of the first two rings and the stationary abutment, for urging said ring in one axial direction; and means adjustably secured on said hub, providing an adjustable abutment for the other of said first two rings.

6. In a chuck of the type described, the combination of a pair of members, to wit va chuck body having a hub, and a jaw control ring loosely tted on said hub for rotation thereon, one of said members having a conical bearing surface facing the other member; means indiscontinuous ring formation, between said members, having a conical surface for contact with'said conical bearing surface of one of said members, providing a bearing for the jaw control ring on the chuck hub; an abutment .member secured Yon said hub in an axially adjustable position; and a sinuous resilient steel strip in ring formation, interposed between said means and said abut- 7. In a chuck of the type described, the combination of a pair of members, to wit a chuck body having a hub, and a jaw control ring loosely fitted on said hub for rotation thereon, one of said members having a conical bearing surface facing the other member; means in discontinuous ring formation, between said members, having a conical surface for contact with said conical bearing surface of one of said members, providing a bearing for the jaw control ring on the chuck hub; at least one stop member in outwardly protruding position on said hub, projection into a gap of said discontinuous ring means, for holding the latter against rotation; and means adjustably secured on said hub, in operative contact Wtih the first-named means for urging the same in wedging direction.

8. In a chuck of the type described, the combination of a chuck body having a hub; a jaw control ring loosely fitted on said hub for rota;- tion thereon; and means providing a bearing for said ring on said hub, including a set 0f rollers between. non parallel, co-axial roller races one of which is adjustable in axial position.

ETTORE BUGATTI.

REFERENCES CITED The following references are of record in the ie of this patent:

UNITED STATES PATENTS