US2604018A - High-speed milling machine - Google Patents

Description

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HIGH-SPEED MILLING MACHINE Filed May 11. 1949 I 6 Sheets-Sheet s Patented July 22, i952 HIGH-SPEED MILLING MACHINE Theodore 8., See; Hammond, Ind., assignor to La SalleSteel Company, Chicago, 111.,. a. corporation -cf-bela'ware f ApplicationMay 11, 1949, Serial No. 92,725,

This invention relates to machines for theremoval of material from round; metal bar stock and more particularlyto a millingmachinefor round bars adapted for efficient operation with cutter speeds Substantially higher than those commercially employed today.

' In my co-pendingapplication Serial No. 7,372 filed February 10, 1948, there is discloseda new and improved methodof milling metal-surfaces and a cutter adapted for use 'in'the-'- practice of the method. According'to my new method accel erated operations," inc'1 udingcutter speeds and work feed rates, are obtained which "are'substantially faster than those nowemployed'or now available. Present 'day machinesare' not built to operate at such vastly increased-speeds; Accordingly the successful practice of -the new method at such speeds involves -the design and construc tion of machines having greatlyincreased spindle speeds for-cutters, greatly increased feeding rates for the work pieces and; equally important, new and improved structural or machine arrange-' ments adapted to accommodate such accelerated speeds and rates of feed. y j 1 a 3 In designing and'constructing new machines of, this character, the naturalitendency is towards heavier, more: complicated sand therefore more expensive structures. Y However, an. important object of thepresent'invention resides in the provision of a novel machineof this character which, while comparatively simplein design,and construction, is sufficiently rugged for successful operation at these muchly elevated speeds and is comparatively inexpensive to manufacture. Not only are commercial milling machines of today slow in operation and performance but current research teaches that the successful milling of metal surfaces shouldbeperformed at, slow speeds and argues away from the; employment ofhigher rates. Furthermore, when" the literature does speak of high or higher millingspeeds, it refers to rates of operation'tliat are only reasonably increased beyond those'employed today. and does not contemplate the vastly. increased speedsobtained and employed by the present novel tech nique. i

v Thus where spindle speedshave heretofore been experimentally stepped up increment by increment the presentin'vention contemplatesemploying feed rates and surface. foot ratesfthat at the lowest are substantially above those being femployed'toda'y. The machine which forms" the sub} 4 Glailns. (CI. 90-46) 'p-anying drawing, in which,

v ,2 high speeds and occasionally disclosesan isolated attempt toperformsomespecial cutting'oper'ation at an elevated swiftness, nothingin theprior art discloses the performance of standard or commercial milling operations at the speeds obtained or in the manner described in this and the copending application referred to above.

In accordance with the foregoing desideratum a feature of the. present invention resides in the provision of a new and improved bar milling machine designed to operate at what may be termed super speeds without undue vibration. This feature is accomplished-to a-favorable extent by, mounting the driving mechanism and the housings for the cutters upon a common axis.

Another feature of the invention resideslin-the provision ina machine of this character of a cutter assembly and supporting parts which permits convenient replacement, of cutters and adapts the machine to. operate successfully on work pieces and with cutters of difierent-size's:

Other objects and features or the invention will become apparent from :a' reading-of the following specification in thellig-htvof. the accom- Figure -1- is a-top plan view of'a milling machine constructed in accordance with the present inven- Figure 2 is a view inlfront machine shown in Figural,

s Figure 3 isan --en1arged;view ofthe machine, also in front elevation, with-certain parts broken away,

Figure 4is aview' in side'elevation;:-partlyin section, of the machine of'the earlierfigures;

I Figure 5' is a side elevational view, similar-to Figure 4, showing. the driving-apparatus; and

Figures 6,7, 81 and-9* are detail vi'ewsof the main frame, the housing for the driving iii-rechanism, and a section of thework support. 7.

As, shown in Figure 1 o'f-t-hei drawing'sythe assembly comprises, in general, a plurality. of cutters It and I2, mounted on oppositelyeittehding shafts I4 andlfiwhich aredriven at-a cce'lerelevation of the vated splee'ds by means of gear trains 'mou-nted in housing l8 and 20,- Adjusting' mechanisms 22* V positioned at the opposite side of the machine are provided to feed the work away from the machine after it passes from the cutters I8 and Turning now to Figure 2, it will be seen that the machine may be conveniently mounted on a concrete floor B provided with pits Cand D within which 'are. positioned electrie motors 34 and 36. These motors diive the cutters I8 and I2 at elevated speeds through acceleration gears mounted in the housings I8 and 28. A main frame 48 is secured to the floor or deck 13 in any, suitable manner and supports the milling assembly.

As shown in Figure 3, the main frame 48 is provided with bearings 42, '44 and 46 which provide rotatable support for a plurality of stub or rocker shafts 48 and 58. The inner extremities of these shafts terminate near one another within the bearing 44 as illustrated. Cutter housings 52 and 54, as shown in Figures 3 and 4 are mounted 'on'the stub shafts '48 and 58 respectively. These housings are yokeshaped at their upper extremities, thehousing '52 being divided into a plurality of arms 56, 58 and the housing 54 into a plurality of arms68, 62 (Figure 1). Each of these arms is bifurcated to provide slots for the reception of wedge-shaped members 64 depending from and supporting bearings 66 (Figure 4). Pins or keys 68 lock the bearings to the housing arms.

The oppositely extending cutter drive shafts I4 and I6 are mounted in the bearings 66 and at each smaller than its; predecessor, are mounted in shafts, formed integrally with the housings I8 and 28 and are provided for the purpose of driving. gears '88-'s'plined to the cutter shafts. These geartrains, driven initially by high speed motors cause the cutters to rotate at the high speeds contemplated by the invention as hereafter more fully explained.

The cutter housings ment ormovement towards or away from the axis X of the work piece in order that the milling operation may be performed on work pieces-or with cutters of different diameters. To this'end, each of the cutter housings 52 and 54 is provided with a yoke shaped member 82, 84 (Figures 1 and 4) pivoted thereto. Links 86, 88 connect the yokes with bolts 98 and 92- as clearly shown in Figure 4. These bolts have screw threaded connection with the hubs of hand- wheel members 94 and 96 journaled in the machine frame. Thus, rotation of the hand wheels causes the cutters to-move inwardly or outwardly. v

Referring'to Figures 5, '7 and 8 it will'be seen that the gear housings I8 and 28 are divided along the line I88 in-such a manner that the upper portions of the housings are free to swing or pivot are mounted for adjustbetween the cutters and this apparatus is adjustable in order to accommodate work pieces of different sizes. Figures 1 and 2 show this apparatus generally while Figures 3, 4 and 5 show it in greater detail. A plurality of cross frame members I86 and I88 span the cutter assembly and are secured to the main frame 48. Centrally formed atop these cross frames are web portions I I8, I'I2 each having a smooth, rectangular bore II4 formed therein.

A housing I I6 is inserted within each rectangular bore I I4 and is vertically adjustable by means illustrated in Figure 3. As there shown, bolt members II8 are formed integrally with and adapted to extend upwardly from the cross frames I86 and I88. Each housing II6 is provided with an integrally formed laterally projecting arm I28 having a cylindrical bore therein to receive a bolt member II8. Nuts I22, I24 are threaded on each of the arms II8 on either side of the arm I28 and by adjusting the bolts the height of the projecting arms I28 may be varied and controlled as desired. Set screwsoperated by hand wheels I28, I38 are provided to lock the arms in adjusted position. Y

Mounted within the lower, closed ends of the housings I I6, as shown in Figure 4, are work supporting rolls I32. These rolls are journaled on pins carried by the housings and are freely rotatable. The position of these rolls with respect to the axis X of the work can be adjusted by raising or lowering the housings II6 to accommodate work pieces of different diameters.

Cooperating rolls I34 (also Figure 4) arerotatably mounted in a sleeve I36 pivotallyattached, by means of a pin I48, to a rod or bar I42. The sleeve I36 and the rolls I34 are normally urged toward the bar axis by means of a compression spring I44 but are free to move momentarily away from this axis if such movement is called for in the feed of the bar through the machine. To this latter end, the bar I42 is slidably mounted within a sleeve I58, expanded as shown at I52 to provide an abutment for the spring I44, and having its upper end threaded for engagement with cooperating threads formed Within the hub I54 of a rotary hand wheel I56. Rotation of the latter causes the sleeve --'I58 to rise or descend carrying with it, under compression of the spring I44, the rod I42, the sleeve I36 and the work rolls I34. In 'order to adjust the compression of the spring I44, a second hand Wheel I68 having screw threaded engagement with the upper extremity'of the rod I42 is provided. f 1

Each of the assemblies made up of the housing II6, the sleeve I36 and the two sets of rolls I32 and I34, together with the attendant supporting and adjusting means, comprises a steady rest for the rotating bar stockas it passes lengthwise through the machine; As shown in Figures 1, 2 and 3 these steady rests are positioned on opposite sides of the cutters I8, I2, immediately adjacent thereto, in'such a manner as to support the bar firmly'as it enters and emerges from the bite of the cutter.

Figure 6shows the frame of the machine and the manner in which the cutter housings 52, 54 are mounted on the rock shafts 48 and 58.

' To facilitate removalof chips during amilling' operation the'machine iseduipped .witha .suc tion chute I64. If the cutters are driven to rotate in the direction indicated bythe arrows in Fi ure 41 the chips will. have a tendency to] fall into the chute and be disposed of without difflculty.

In operation, round bar stock is fed to the machine in any suitable manner. The rolls of the so-called Medart machine can be regulated to control the speed of rotation of the round bars as they are milled.

In the Medart machine one roll is cylindrical and the other concave and by adjusting the angularity and the speed of rotation of the rolls, the linear rate of feed of the bars can be controlled and likewise the speed of rotation of the bars about their own axes may be regulated. As

stated, a machine'of this character is disclosed in Patent No. 2,132,976 granted to Siegerist on October 11, 1938.

Ordinarily a depth of cut of about & of an inch will be taken and the diameter of the cutters will ordinarily vary from 4 to 12 inches. The cutter itself is preferably constructed in accordance with my co-pending application first above mentioned.

As already stated, it is intended that this machine should be capable of operation at speeds substantially above those now employed. Also it is contemplated that its use, in so far as matrials are concerned, should be universal. Thus the machine may be employed to machine the surface of both ferrous and non-ferrous bar stock. Today special machines are generally constructed for each of these materials. Of them, steel and cast iron are the most difiicult to machine and previously they have been handled at comparatively low speeds and feeds. For instance the top feed rate on steel has generally been about 90 I. P. M. (inches per minute) and the top surface foot rate of the cutter 1000 S. F. M. (surface feet per minute). In accordance with my invention the I. P. M. will preferably commence at 120 and go as high as 3,000 or even higher.

Similarly, the surface foot rate will be increased from a range of 250 (to an occasional 1,000) to a range of 1,500 to 20,000 or higher. The upper limits of my invention as set forth herein and in co-pending applications will generally depend on physical limitations of machine and cutter design only and the lower limits will lie substantially above those previously deemed feasible or possible. Particularly is this true of the ferrous field where I have discovered, contrary to popular belief, that the higher speeds and feeds the more facile the operation when my cutters and machine construction are employed.

Although in the machine illustrated in the accompanying drawings the work pieces (round metal bars) are fed past the cutters in a horizontal direction, it will be appreciated that a person skilled in the art could readily provide a vertically downward or upward feed for Work pieces such as flats, squares, hexagons or the like or could, in the vertical mill, substitute form cutters for the cylindrical cutters for operation on special shapes and sections without departing from the scope of the invention as set forth in the appended claims. axes shown in the illustrated embodiment could be disposed vertically for a similar purpose al though this would perhaps be less satisfactory from the standpoint of machine balance.

Other changes and modifications in construction and arrangement of parts will occur to those skilled in the art and may also be employed within the meaning of the following claims.

.Similarly the cutter Having thus described the invention, what is claimed as new and for which protection is desired, is:

1. A machine for milling round metal bar stock, constructed and arranged for operation at a work piece feed rate of above I. P. M. and a cutting speed of above 1500 is. F. M., said machine comprising, in combination, a pair of opposed rotary cutters, a rock shaft, cutter housings pivoted to said rock shaft and carrying said cutters, and independent means for varying and controlling the position of each of said cutters with respect to the other. Y

2. A machine for milling round metal bar stock at high speeds comprising a pair of substantially parallel cutter shafts, a pair of opposed rotary cutters respectively disposed on said cutter shafts, a rock shaft, cutter housings pivoted on said rock shaft and having bifurcated upper ends for supporting said cutter shafts at opposite ends of said cutters, and independent means for varying and controlling the position of each of said cutters with respect to the other.

3. A machine for milling round metal bar stock at high speeds comprising a frame, rock shaft means extending across said frame and projecting from opposite ends thereof, a pair of cutter shafts respectively projecting beyond the opposite ends of said frame, a pair of opposed rotary cutters respectively carried by said cutter shafts, cutter housings pivoted on said rock shaft and having bifurcated upper ends for respectively supporting said cutter shafts at opposite ends of said cutters, and driving means at each end of said frame each including gears mounted on the projecting ends of said rock shaft means and said cutter shafts for rotating said cutters, and means for independently adjusting said cutters and the associated driving means therefor arcuately about said rock shaft to vary the position of said cutters relative to each other.

4. A machine for milling round metal bar stock at high speeds comprising a cutter shaft, a cutter on said shaft intermediate the ends thereof, a rock shaft, a cutter support pivoted on said rock shaft and having a bifurcated upper end, bearing means on said upper end for supporting said cutter shaft at opposite ends of said cutter, means including gears respectively mounted on said cutter shaft and on said rock shaft for rotating said cutter, a stationary gear housing enclosing said gear on said rock shaft, and an adjustable gear housing enclosing said gear on said cutter shaft, said gear housings having arcuate meeting edges formed on a radius about said rock shaft, to permit arcuate adjustment of the cutter about the rock shaft.

THEODORE S. SEE.

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

UNITED STATES PATENTS Number Name Date 31,007 Rockwood Aug. 11, 1868 118,200 Cogswell Aug. 22, 1871 1,411,474 Brightman 1 Apr. 4, 1922 1,809,880 Wise June 16, 1931 2,231,589 Olivetti Feb. 11, 1941 FOREIGN PATENTS Number Country Date 49,109 Germany Oct. 17, 1889

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