US1656847A

US1656847A - Method and apparatus for die rolling

Info

Publication number: US1656847A
Application number: US725554A
Authority: US
Inventors: William P Witherow
Original assignee: COLONIAL TRUST CO
Current assignee: COLONIAL TRUST CO
Priority date: 1924-07-12
Filing date: 1924-07-12
Publication date: 1928-01-17
Anticipated expiration: 1945-01-17

Description

Patented Jan.. l?, 1928.

WILLAM P. EVITHEIROW, OF PTTSBURGH, PENNSYLVANIA, ASSIGNOR, BY MESNE AS- SGNll/IENTS, TO COLONIAL TRUST COMPANY, TRUSTEE, 0F

PITTSBURGH, PENNSYL VANIA, A CORPGRATION OF FENNSYLV'ANIA.

METHOD AND APPARATUS FOR DIE ROLLING.

Application filed July 12,

This invention relates broadly to die rolling', and certain features thereoi are applicable to die rolling in general, while other features thereof iind particular application in the die rolling of articles having a relatively short portion ot' `greater cross section than adjacent portions, as, for example, a die rolled article having a collared portion.

ln metal rolling, it is general practice to drive one roll of the mill from the power source, and to connect the other roll to the driven roll by means of gearing, the gears being connected to the rolls through suitable means, such as spindles, to permit adjustment of the rolls relative to one another.

l have found that in setting up a pair ot die rolls preparatory to rolling, particularly where it is desired to form an article which is bilaterally symmetrical with respect to the longitudinal axis, it is highlypdesirable to set the driven roll in advance of the driving roll. The amount of setting; depends on a number of features, particularly the draft, and the result of such setting' ahead is that the portions of the article which are formed in the two rolls coincide with one another exactly when the driven roll has been set ahead in the proper amount. `When such compensation is not made, the e'ect on the roll is as though the portion formed in the driven roll had been slipped a short distance along the length ci the article relative to the portion formed in the driving roll. Obviously, far more satisfactory results can be attained When such adjustment is made.

l believe that the necessity tor such adjustment arises because oi the twist in the length oit the spindles and the deection of the pinion teeth when the mill is under load. All et these deflections are very slight but would probably be sucient to give rise to the situation which my adjustment is inn tended to overcome, and such deilections would not show up when operating the mill without passing any steel therethrough, or

it, for example, some very soit substance, such as plasticine, were rolled therein.

Another Jfeature et my invention which is particularly applicable to the rolling ot articles havingI a relatively short portion et diderent cross sectional area than the adjacent portions, is the dimensioning1 ot a matrix portion in the driven roll for form 1 ing such portion et' the article as compared 1924. Serial No. 725,554.

with the corresponding matrix portion oi the driving roll, I have found that in rolling an article such as a collared shaft, it is desirable to malte the matrix portion in the driven roll a little longer than the correspending matrix portion in the driving roll.

lt is a general theory in ordinary rolling that the force between the rolls is entirely a force tending to separate the rolls and has no component alongrl the line of the article being rolled. rlhis theory is advanced because of the fact that in general rolling practice the bar being fed to the rolls moves at a uniform speed. As the productI leaving` the rolls also moves at uniform speed, there can be no accelerating torce.

Observation, however, shows that this is not true in die rolling, for in such rolling a delivery speed of the article is dependent upon the varyingpercentan'e ot reduction. Under these conditions` there must at varying times exist between the die rolls a force in addition to the spreadingr torce, and one which is exerted along the axis ot 'the bar being rolled. This force will either be in the direction of the article being rolled or in opposition thereto dependingr on whether there is an enlargement or a reduction in the size ot the productat a particular instance. This orce is the force required to accelerate the entire bar on the delivery side ot the mill from its then velocity to a dita ferent velocity imposed by the variation in cross section.

,lf believe that with variations in this Jforce alone the bar, the pressure between the pinion teeth will also vary. Stated in another way, the force required to rotate the driven roll and accomplish the wor-lr of rolling* will vary with changes in cross section, and there will therefore be changes in the relative setting ot the driven roll as compared with the driving roll. vllhis would require a continuous variation in the amount the driven roll is set ahead of the driving; roll. but such variation cannot readily be effected when 'the mill is in operation, and in any event, could not be accomplished without affecting all portions of the bar. l", therefore, provide a compensation for a particular portion ot the article by varying the length of the con responding portion ot the roll matrix from theoretical dimensions. The above theory, which ll believe to be a true explanation,

titl

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ltlli affords an understanding of the difficulties which are overcome by my invention and will be found of value in determining which way compensation is to be made and in what amount. However, I do not limit myself to such theory, or to the correctness thereof.

In the accompanying drawings which show, for purposes of illustration only, a particular application of my invention,

' Figure l is a side elevation of a die rolled automobile drive shaft;

Figure 2 is a developed view of the driven roll for rolling the article shown in Figure 1;

Figure 3 is a similar view showing the driving roll, and

Figure 4 is a cross sectional view through a pair of rolls constructed in accordance with the la out of Figures 2 and 3, and showing their relative setting.

The article shown in Figure l is an automobile propeller shaft S having a collared portion C. Figure 4 shows a pair of rolls as set up in the mill for rollin such articles, the direction of rotation glacing indicated by arrows. The lower roll 2 is the driving roll and the upper roll 3 is the driven roll. Figure 4 shows the relative set ting of the two rolls prior to starting up the mill and it will be observed from this figure that the various matrix portions of the roll 3 are slightly angularly advanced with respect to the corresponding matrix portions of the driving roll 2. As above set out, this is a general setting ahead to compensate for a twist in the spindles, deflecilgn of the pinion teeth under load and the In Figure 1, Z indicates the linear dimension of the collared portion. Figure 2 shows that the corresponding matrix d in the driven roll is longer than the corresponding matrix d for the driving roll shown in Figure 3, or, to state it in another way, the leading edge e of the collar portion of the -matrix in the driven roll is in advance of the corresponding leading edge e in the driving roll, as clearly indicated in Figure 4. This advance of the leading edge is greater than the general setting ahead of the driven roll, the amount of compensation or additional settin ahead for this particular the difference in dra between one portion of the article andk another, the cross sectional area of the sections on each side of the collar, the temperature and composition of the metal, etc.

A pair of rolls formed as illustrated in Figures 2 and 3 and set as disclosed in Figure 4 in accordance with the present invention will result in the rolling of an article such as shown invFigure 1, wherein the por tions formed in the upper and lower rolls iptortion depen ing on correspond with one another throughout the length of the bar, regardless of variations in cross section of the rolled work.

I thus overcome a great dii'iculty which has been experienced in die rolling by providing a mill having a driving and a driven roll, and setting the driven roll ahead of the driving roll. I further provide for a supplemental setting ahead of various portions of the rolls in amounts greater than the general setting ahead.

It will be understood that my broad invention contemplates the setting ahead of the varying portions in accordance with the reduction at such points, since apparently the amount of such setting ahead varies with the reduction. This variation in the setting ahead effect a corresponding variation in the load between the pinion teeth. Actual application of the invention, however, shows that it is only when a relatively abrupt change in section is encountered that t e load varies in such an amount as to require a special compensation for a )articular roll portion, and that for general practice, the above disclosure of setting ahead all portions of the driven roll as compared with the driving roll and only making a special compensation when an abrupt change of section is encountered, will give perfectly satisfactory results.

It will be apparent that I have shown and described only an illustrative example of my invention, and that it may be otherwise embodied and carried out within the scope of the following claims.

I claim:

l. In the method of die rolling in a mill having a driving roll and a driven roll, the steps consist-ing'in vproviding co-operating matrix portions in the two rolls, placing the matrix portions of the driven roll in advance ot the corresponding matrix portions of the driving roll in amounts corresponding to the amount of reduction in the mill by such matrix portions, passing a leader between such rolls and impressing substantially like configurations. by each roll on the leader, substantially as described.

2. In the method of die rolling an article having a relatively short portion of different crosssectional area than the adjacent ortions of the article in a mill having a dliiving and a driven roll, the steps consisting in forming a matrix ortion of relatively greater length in the riven roll than in the driving rc1 for rolling said ortion and passing a leader between suc rolls, the matrix portions being so related as to impress su stantially like configurations on the leader, substantially as described.

3. In the method of die rolling with a pair of rolls having corresponding matrix portions, the steps consisting in varying the setting of a. roll matrix portion in one roll ttl relative to the corresponding roll matrix ortion in the other roll to compensate for vinertia forces set up in the article being produce an article wherein the matrix portions form corresponding (article portions in proper relation to one another, substantially as described. v

4., A pair of die rolls adapted to produce an article having substantially equal por-v tions lying adjacent one another on opposite sides of the median line of the blank, said die rolls having matrix portions therein adapted to produce such article portions, the matrix portion in one roll didering Jfrom the matrix portion in the other roll, such portions being so dimensioned as to impress substantially like oppositely disposed configurations on the material being rolled, substantially as described.

5. pair of die rolls having generally similar matrices adapted to cooperate with one another and to form an article which is substantially symmetrical about the median* line of the article, said die rolls having at least some matrix portions which correspond to one another but which are of different length around the roll, substantially as descri-ned.,

d In the method of die rolling in a mill having a driving roll and a driven roll, the steps consisting in providing cooperating matrix portions in the two rolls, placing the matrix ortions of the driven roll in advance o the corresponding matrix portions ot the driving roll in amounts correspond- 'ing to the amount of reduction -in the mill by such matrix portions, corresponding matrix portions in the two rolls being relatively of such size and shape as to produce substantially like article portions, a matrix portion in the driven roll being placed in advance of the corresponding portion Ain the driving roll in such amounts that when a leader is passed between the rolls, the artions ticle ortions produced by such matrix por- Ilie substantially side by side, and passing a leader between the rolls, substantially as described.

7. In the method of die rolling an article having a. relatively short portion of different lthe rolls theyI substantially i cross-sectional area than the adjacent portions of the article in a mill having a driving and a driven roll, the steps consisting in setting the driven roll ahead of the drivin@ roll, and also providing a matrix portion o? relatively greater length in the driven roll than in the driving roll for rollin said portion, the matrix ortion in the riven roll being set ahead o the corresponding matrix portion in the driving roll in such amount, and being of such relative length that the matrix portions of the two rolls impress substantially like congurations on the material being rolled, substantially as described.

8. In the method of die rolling to produce blanks which are bilaterally symmetrical relative to the longitudinal `axes of the blanks, the steps consisting in providing a pair of rolls having matrix portions which correspond to one another, but which are dissimilar one from the other in at least certain portions thereof, a matrix portion in one roll didering in dimensions from a corresponding matrix portion in the other roll in such amount that when a leader is passed between the rolls they are e'ect-ive :tor impressing substantially like congurations on the material being rolled, and passing a leader between the rolls, substantially as described.

9. In the method of die rolling to produce blanks which are bilaterally symmetrical relative to the longitudinal axes of the blanks, the steps consisting in providing a pair 01E rolls having matrix portions which .correspond to onevanother, but which are dissimilar one from the other in at least certain portions thereof, a matrix portion in one roll diiering -in dimensionsffrom a corresponding matrix port-ion in the other roll in such amount that when a leader is passed between are effective for impressing ke congurations on the material being rolled, setting one of the rolls ahead of the other in an amount suilicient to cause the article portions produced by cor- (lll responding matrix portions inthe two rolls v to lie side by side, and passing a leader between the rolls, substantially as described. l In testimony whereof I have hereunto set wnlLIAM P. WITHEROW.

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