US1684206A - Means for rolling thin sections - Google Patents

Description

Sept. 11, 1928. 1,684,206

J. w. SMITH MEANS FOR ROLLING THIN SECTIONS Filed March 14, 1927 2 Sheets-Sheet 1 g l II:III; R

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FIG- I.

Sept. 11, 1928.

J. W. SMITH MEANS FOR ROLLING THIN SECTIONS Filed March 14, 1927 2 Sheets-Sheet IIIIIIIIIE INVENTOR:

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BY W

ATTORNEYS.

Patented Sept. 11, 1928.

UNITED STATES 1,684,206 PATENT OFFICE.

JOHN W. SMITH, OF PHILADELPHIA, PENNSYLVANIA.

MEANS FOR ROLLING THIN SECTIONS.

Application filed March 14, 1927. Serial No. 175,335.

tember, 1926; I have set forth a two-stage process of fabricating thin sections involving a high-speed rolling mill for the second stage. Under such process I am enabled to roll die forged blanks to thin sections by utilizing the heat retained in the blankafter a first stage forging. Cycloidal rolling, by multiple passes, has been found highly advantageous in producing comparatively thin sections from relatively thick material when carried out at high speeds inasmuch as, such sections expand more readily when cycloidally rolled than when rolled with" a straight'line motion.

Cyclodial rolling and multiple drive eliminates the buckling or plaiting of the metal when rolling near the outer edge and facilitates reducing a comparatively thick material to the required thin section in one pass, making use of the second pass as a finish, or eliminating it entirely on certain classes of work.

Arcograph rolling is often an advantage in producing the final shape. My integral hub and brake drum is a. typical example to illustrate my multiple drive arcograph rolling and forms a part of my process for making integral hubs and brake drums and similar articles.

Maximum reduction in reducing metal by the rolling process is to be ha when power is applied to all of the rolling means 3).) this particular case, one revolving forming die is employed, and two reducmg rollers, each of the three means being supplied with power.

Having briefly outlined the mechanical organization involved I will now set forth the novel features more particularly. Primarily, it is well to here remark, that during the rolling period I aim to maintaln co-operative synchronized torque between the motors driving the rolling and forming means. Such synchronized or balanced torque might be attained by mechanical means, but I prefer to control the momentum of the forming die so that it attains the proper 0 synchronized speed when the milling rollers are initially moved into rolling location, inasmuch as a surface speed change of four-- to-one between the outer and inner peripl cry may be necessary in some cases. In other 5 words, I aim to maintain a co-operative speed and torque for the forming die with a balanced torque as between the motors driving the rolling means, by automatically synchronizing the surface speeds of the 7 forming die with the milling rollers.

The primary object of the instant'invention, accordingly, is to roll thin sectionswith a combined radialor cycloidal'and synchronized surface speed as between the forming and rolling means at all the varying cooperative positions assumed incidental to the rolling operation.

Another object is to efiiciently fabricate such sections with greater rapidity than is at present ossible by known means.

Other ob ects and advantages will be apparentfrom the following description of a typical means effective to carry out this invention; while the appended claims serve to define those features alleged as novel and patentable.

In the drawings Fig. I is a sectional view of the upper portion of a rolling mill adapted to my present improvements.

Fig. II is'an axial section through a preformed or forged blank ready for rolling in accordance with this invention.

Fig. III is a similar view illustrative of the section after radial rolling in accordance with one phase of the present invention; and,

Fig. IV is a corresponding section of a typical product of the present invention subsequent to a final stamping and machining operation.

Before entering upon a detailed explanation of the mechanism typified as suitable for carrying out my presentwimprovements in the art of rolling thin sections, I would here remark that this invention is mainly-- In view of the fact that the mill illustrated chronized multiple-drive instrumentalities.

in Fig. I generally conforms to that described in my co-pending application Serial Number 713,425, supra: the following deplace by a cap-piece 9 seating over an annular ledge of the housing 6, and a thrust bearing 10 thereunder, so as to ensure perfect freedom of rotation. As a means for driving the revolving die head 8 I-preferably-make use of a co-operatetorque variablespeed motor 11,. designed to furnish the required torque or moment of force required by the revolving die 5."

This motor 11 is supported upon the top of the mill 6 by means of a suitable mounting 13 secured to the ring 12, while the shaft 14 of said motor is coupled direct to the revolving die head cap-piece 9 by a coupling 15.

A suitable blank 16such as shown in Fig. II for exampleis sustained in the mill resting against the extraction pin 17 and securely held in place by a stud 18 mounted on the turret-head 19, which has capacity for rotary-and vertically slidable-movement; all as described in the hereinbefore referred to co-pending application.

The rollers 20 functional to radially expand the blank 16 relative to the forming and rolling die 5 are provided with shafts 21 journaled in ball and roller bearings 22, 23respectivelyin turn appropriately secured in trunnion housin s; 24, 25 sustained by a trunnion support mounted on the mill main columns 26. Each housing 24, 25 is fitted with a cap piece 27 serving to support the electric motors 28, 29, respectively; which are directly connected to the aforesaid shafts 21 through the medium of con lings 30.

aving briefly outlined the mechanical organization involved I will nowset forth the novel features more particularly. Primaril it is well to here remark, that during t e rolling period I aim to maintain co-operative synchronized torque between the motor 11 and motors 28, 29. Such synchronized or balanced torque might be attained b mechanical means, but I prefer to contro the momentum of the forming die 5 so that it attains the proper synchronized speed when the millin rollers 20, 20 are initially moved into r'o ling location adja cent the blank boss 31, inasmuch as a surface change of four-to-one between the periphery and said boss may be necessary in some cases. In other words, I aim to maintain a co-operative torque for the die 5 with a co-operative balanced torque as between the motors 28, 29 by automatically synchronizing the surface speeds of the die 5 with that of the rollers 20.

In conjunction with the means just explained I employ a rheostat 34 for automatically regulating the strength of a shunt field 35 of the motor 11, with a co-ordinating connection 36, pivoted at 37 to one25 for example-of the trunnion housings, and sim ilarly connected at 38 to the switch arm 39 of said rheostat. Thus it will be readily appreciated that, as themilling rollers 20,

20 swing radially relative to the forming die 5, the resistance in the shunt field circuit 35 r of the motor is automatically controlled.

The requirements for driving rollers 20, 20 are constant revolutions per minute and constant torque. V

The requirements for driving the die ,5 are entirely dilierent. Near the center the revolutions per minute are high with a correspondingly light torque, and on the outer edge the revolutions per minute are low with a heavy torque. The above requirements are in accord with shunt wound motor s ccifications requiring a light torque wit a gvqalk field, and a heavy torque with a strong Rolling at constant periphery speed as set forth is an important factor 1n my process. Applying the automatic rheostat to motor 11, the re uirements are more easily met than if app ied to motors 28 and 29..

The three motor or multiple drive herein shown represents a drive of the simplest form. The die head 8 is driven by a variable speed shunt wound motor with an automatically operated rheostat 34. The milling rollers 20 are driven by motors 28 and 29 which are com ound wound motors with a suitable preme itated speed factor between no load and full load.

In this particular case the series field cir-.

cuits 32 of. motors 28 and 29 are connected in parallel. Some motor manufacturers would prefer to connect the series fields in series formotors 28 and 29. The shunt field for motors 28 and 29 are herein shown in parallel' but they may also be connected in series. Motor 11 may also be supplied with a series field winding connected in series with motors 28 and 29 as a means of augmenting co-operative performance.

The power lines for the motors 11 and 28, 29 are, respectively, designated by the .numerals 40, 41, although it will be readily understood that all of said motors may be served from one such line; whilegisuch indicationsin this, ;case--are solely' by way of illustrating diagrammatically one convenient arrangement.

Referring onceagain to I it W111 be loo remarked that I have shown the face of the die 5 is of a curvature not struck from a common center but rather of gradual deviation outwardly therefrom, with the result that the milling rollers 20, 20 roll the blank 16 cycloidally to tapering cross section. On the other hand m present invention is par; ticularly well a apted for the rolling of thin sections having the dished contour depicted at 42 in Fig. III, that is to say with a definite radial curvature and of even seetional gage. Such profiled sections are particularly well adapted for subsequent die stamping to the sectional formshown at 43 in Fig. IV-and useful as integral hub and brake drum units for thin section spokeless wheels.

From the foregoing it is thought my present invention will be well understood, and while I have outlined one typical embodiment thereof, it is to be understood that I hereby reserve the right to vary the means adaptable for ensuring the generic aspects of said invention so far as is compatible with reasonable interpretation accorded the subjoined claims.

Having thus described my invention, I claim:

1. In a rolling mill embodying a rotary forming die and co-operativc rolling means movable radially of the forming die, the combination of means with automatic control to positively drive the forming die and the rolling means at synchronized surface speed in different co-operative positions assumed incidental to the rolling operation.

2. In a rolling mill embodyin a rotary forming die and co-operative rol ing means movable radially of the forming die, the combination of means to positively drive the rolling means at synchronous speed, separate means to drive the rotary forming die, and automatic means to control the drive means aforesaid for maintenance of synchronized surface speeds between the rota forming die and the rolling means in di erent co-operative positions incidental to the rolling operation.

3. In a rolling mill embodyin a rotary forming die and co-operative rolfing means movable radially of the forming die, the combination of means to positively drive the rolling means at synchronous speed, separate means to drive the rotary forming die, and automatic means controlling coordination of the respective drive means for maintenance of co-operative balanced torque between the several drive means.

4. In a rolling mill embodying a rotary forming die and co-operative rolling means movable radially of the forming die, the combination of means to positively drive the rolling means at synchronous speed, sepa rate means to drive the rotary forming die, and a control functional to co-operatively balance the torque between the respective drive means.

5. In a rolling mill embodying a rotary forming die and co-operative rolling means movable radially of the forming die, the combination of an electric motor to positively drive the rolling means at synchronous speed, a separate electric motor to drive the rotary forming die, a rheostat in circuit with said latter motor, and means adapted to automatically vary the strength of a shunt fieldthrou h said rheostatsynchronously controlled by the varying location of the rolling means.

6. In a rolling mill embodying a rotary forming die and co-operative multiple-rolling means movable radially of the forming die, the combination of an electric motor with means to varyingly balance the speed of each rolling unit, a separate electric motor to drive the rotary forming die, and a rheostat--operatively co-ordinated with one of the rolling units-functional to vary the electro-motive force through a shunt field of the forming die motor, whereby the torque of the latter is co-operatively balanced relative to that of the rolling unit motors incidental to the peripheral speeds of said rolling units.

7. In a rolling mill embodyin a rotary forming die and co-operative mu ti le-rolling means movable radially of the orming die, the combination of an electric motor with a series and shunt fields adapted to each rolling unit, a separate similar motor to drive the rotary forming die, .and a rheostat co-ordinated with one of the rolling units functional to vary the strength of the shunt field of the rotary forming die motor whereby the torque of the several motors is co-operatively balanced.

8. In a rolling mill embodying a rotary forming die and co-operative multiple-rolling means movable radially of the forming die, the combination of an electric motor for each operative unit with a parallel circuit for series and shunt fields, means functional to co-operatively balance the torque between the respective motors, and the aforesaid series field and shunt field circuits being connected in parallel.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this 10th day of March, 1927.

JOHN W. SMITH.

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