Nov. 25, 1958 M, KRONENBERG 2,861,471 BALANCING DEVICE Filed Aug. 27, 1956

IN VEN T0R. MAX KEONE/VBEEG United States» Patent 0 C€ 2,861,471 I . Bittérltedé ‘Now-L253} 195,8 VI; ing radialv insertion and; withdrawal7 oflth'ei- weights? at diametrically‘ opposite positions from‘: thei'ringsr . 2,361,474 Another object is‘ to Provide in: combination-with a chuckQ or: face-1 plate; an integral5 or‘ attached graduated BALANCING. nnvrcn. ring r to‘ permit? presettingmhdirep‘etitive ‘setting-‘of *bala'nc'e Max Kronenberg, Cincinnati, Ohio, assignor to The K. weights to any‘ desired-l angular‘ positioni for.‘ tlielpurpose Le‘ Blond ‘Machine Tool‘Coi," Cincinnati, Ohio,- , a cor porationof Delaware‘ ' - ~ ' ' of reducing or- eliminating:v disturbing‘ vibration: in~lathes, ' milling machines: and; otlier" machines for." chuck?“ work. Andfazfurther object is3to1provider=a:balancingmingi'on Application' ' 2'Claims:August (61:74-573)1956,_SerialsNo. 10 a: chuckf orvfa'ce- platehaving radially- dispose‘dl slots‘: ar range'd5 on‘1 the‘ periphery: of‘ the: ring- ' so.‘ that the balance Weights may be introduced into a continuous clamping groove to permit positioning of said weight in any cir This invention is directed to improvements in balanc cumferential position on the ring. ing devices for machine tool spindles especially adapted 15 Further features and advantages of this invention will to balancing chucks, face plates,'and ?xtures on such appear from a detailed description of the drawings in spindles. which: In machine tools such as lathes utilizing present day Fig. 1 is a side elevation of a chuck mounted on a high spindle speeds unbalance in the chucks and face 20 lathe spindle and having the balancing ring incorporating plates becomes a problem due to the position of the the features of this invention. scroll and jaws when adjustments are made therein for Fig. 2'is a view indicated by the line 2-2 in Fig. 1. di?erent sized work pieces. The moment of inertial of Fig. 3 is an enlarged fragmentary sectional view on the a chuck or face plate increases and the unbalance changes line 3+3 of Fig. 2. as the jaws are moved toward the outside of the chuck 25 Fig. 4 is an enlarged fragmentary view indicated by body to receive work pieces with large diameters. Such the line 4—4 in Fig. 2. change in moment of inertial and/or unbalance can be As an example of one embodiment of this invention duplicated each time when the same position of scroll there is shown a regular three-jaw chuck 10 mounted and jaws is obtained. It is therefore found possible to on the spindle 11 of a lathe headstock 12. Fixed to the compensate such unbalance in advance or whenever de 30 rear face 13 of the chuck 10 by suitable screws 14 and sired for each position of the jaws or speed of rotation pins 15 is the balancing ring 16. In the rear face 17 of the chuck or face plate by shifting balance masses of the ring 16 is formed an annular T-slot 18 having a to a predetermined position which can readily be located bottom 19 and radially disposed clamping surfaces 20 by the operator when the chuck or face plate is equipped and the annular groove de?ned by the sides 21. Diamet with a grooved and graduated ring to receive and locate 35 rically oppositely disposed cutter clearance openings 22 the balance masses. are provided to insure proper initial balance of the As an example, tests have shown that the headstock ring 10. ‘ vibration of a lathe rotating at a spindle speed of 1000 At diametrically opposite points on the periphery 31 R. P. M. can be minimized by shifting a balance weight of the ring 10 are radially inwardly extending loading of 39.1 grams to an angular position of 255 “ when the 40 slots 24 which extend into the portion of the T-slot 18 _ jaws comprise a circle of about 4'' diameter. When the between the bottom 19 and the clamping surfaces 20 so jaw positions are reduced to 3" diameter, the minimum that balance weights 25 of desired size may be inserted amplitude of vibration at 1000 R. P. M. spindle speed therein. A threaded stud 26 is then screwed into the was obtained by shifting the balance weight to a position threaded bore 27 in the balance weight 25. A washer of 305 °. . _ 28 and nut 29 is then tightened against the rear face 17 No provisions for balancing are made in chucks and of the ring 10 to lock the weight 25 in any desired cir face plates available on the market today and hence none cumferential position. Preferably the stud 26 projects permits of balancing or presetting to the most favorable outwardly from the nut 29 to facilitate manipulation of conditions. The unbalance in present day chucks and the weights to desired location and the stud may be held face plates which cannot be controlled by the operator between the ?ngers of one hand while tightening or generates oscillating forces and corresponding vibrations loosening the nut 29 with the other. A series of graduations 30 extending 360° around the not only at the chuck or face plate or headstock itself periphery 31 of the ring 10 provides accurate reference but also at points remote from the chuck or face plate means for precisely positioning the weight for correcting such as the carriage or tailstock. Vibrations generated 55 particular conditions of unbalance. The weights may in this way prevent the production of good surface ?nish be easily repositioned to diiferent angular locations on on the workpiece when machined on a lathe or machine the ring 10 to take care of various chuck openings, work tool, and also affect the tool life adversely causing rapid pieces or jaw positions and can be easily repeated for the wear and breakdown of the cutting tools and even the machine structure. same conditions by having the graduations readily avail able for easy positioning of the weights. Thus, the chuck One of the objects of this invention is to provide a is always kept in proper balance for a large variety of balancing device which prevents or minimizes the afore working conditions with minimum of skill and effort mentioned vibrations and makes the setting of balance being required to maintain desired balanced conditions. weights a simple repetitive matter of routine due to a It is understood that the balancing ring may be made as novel graduated ring mounted on the chuck or face 65 an integral part of the chuck body as well as an attach plate. able ring as described. It is a further object to provide heavier or lighter While the apparatus herein disclosed and described require.weights in the same. graduated ring as the circumstances constitutes a preferred form of the invention, it is also Still another object is to arrange the clamping means 70 chamcal alteration without departing from the spirit of for the weights on the ring in such agmanner that they the invention and that such mechanical arrangement and may be positioned in any peripheral location while allow commercial adaptation as fall within the scope of the appendant claims are intended to be included herein, 2,861,471 , . _ 4 axially against the ‘radially disposed surfaces of said T-slot Having'thus fully set forth and described this inven in any circumferential position in said T-slot. tion what isclaimed and desired to be obtained by 2. In a chuck balancing device as set forth in claim 1 United States Letters Patent is: wherein there is provided graduatious around said annular 1. A chuck balancing device comprising a continuous groove for indicatively showing the annular positioning annular ring having avcontinu'ous rear face,'means‘.to of said weight about the axis of rotation of the chuck. ?x said rear face‘of said ring to the rear face of a chuck, a continuous annular ET-slot in saidvring having an an References Cited in the iile of this patent nular groove facingrearwardly of the chuck, radially dis posed loading slots opening in the‘ periphery of said ring UNITED STATES PATENTS 10 at diametrically opposite positions thereon, balance . 79,984 Jonesv ______July 14, 1868 weights finsertable-radially into said T-slot through either 430,270 'Cook ______-._ June 17, 1890 of said loading slots-whileisaid ring is ?xed to said chuck, 1,218,689 Nichols ______Mar. 13, 1917 stud means insertable through said annular groove to 2,097,894 > Roche _; ______.._ Nov. 2, 1937 engage said weight, and clampingsnut means on the out- 1 wardly projecting end of said vstud to clamp said weight 15 - 2,543,447 Elrod ______Feb. 21, 1951