US2636406A - Rolling mill for rings - Google Patents

Description

April 28, 1953 F. s. SALTER 2,636,406

ROLLING MILL FOR RINGS INVENTQR. FRANK S/ZM/E Y JALTfR April 28, 1953 F. s. SALTER ROLLING MILL FOR RINGS 2 SHEETS-SHEET 2 Filed Feb. 28, 1951 INVENTOR. TRIM/If SAD/7E) 5/1 LTfR Patented Apr. 28, 1953 ROLLING MILL FOR RINGS Frank Sidney Salter, Parkstone, Poole, England, assignor to The Loewy Engineering Company Limited, London, England, a corporation of Great Britain Application February 28, 1951, Serial No. 213,211

- i In Great Britain March 30, 1950 Claims.

- The invention relates to ring rolling mills in which thewall thickness of annular blanks is reduced and their diameter thereby increased by the combined action of an outer and an inner working roll. Mills of this type are frequently provided with means for guiding the blank during the rolling operation. These means usually comprise rolls which are caused to engage a blank under hydraulic or other pressure, and which have to be gradually retracted as the blank expands during the rolling operation.

' Control of the receding movement of these guide rolls has so far been efiected by hand and requires the constant and close attention of an operator.

It is one of the primary objects of the present invention to provide a ring rolling mill of the type described, in which the receding movement of the blank-guiding means during the rolling operation is automatically controlled so as to relieve the operator of his task of supervising the movement of the guiding means.

, The invention relates in particular to ring rolling mills in which the guiding means are held in engagement with a blank by hydraulic pressur means, and it is characterised in the first place by the provision of means for automatically controlling the hydraulic pressure means in response to the expansion of a blank, in such a way that the guide means are caused to recede at the same rate as the expansion of the blank progresses.

According to'a further feature'of the invention, the aforesaid automatic control means comprise a relief valve for the pressure fluid in said hydraulic pressure means, said relief valve being opened in response to the expansion of a blank, whereby the recession of the guide means is efiected and closed in response to the recession of the guide means upon release of the pressure fluid by the relief valve.

The relief valve and its automatic control means may be incorporated in a hydraulic pressure system having additional and selectively operable circuits for advancing or withdrawing the guide means without the relief valve becoming operative.

Further features of the invention will become apparent from the following specification, in which two embodiments of the invention are described by way, of example, with reference to the accompanying drawings Fig. 1 is a diagrammatic plan view, partly in section, of a ring rolling mill according to the invention, showing only those parts of themill which are essential to the understanding of the invention.

Fig. 2 is a similar view of another embodiment of the mill according to the invention.

Fig. 3 is a section through a valve forming part of the embodiment according to Fig. 2.

. In Fig. 1, i0 is an outer and Il an inner working roll of string rolling mill, both of which are adapted to act simultaneously on the outside and insiderespectively of a blank B, so as to reduce its wall thickness and thereby increase its diameter. One or both of the rolls Ill and H are power-driven, and both rolls are constantly urged towards each other by separate pressure means, whereby the required rolling pressure i produced. The mean for driving the roll or rolls and the pressure means are not shown or described here, as they are not part of the present invention.

Means are provided, comprising rolls l3 and M, to guide a blank B during the rolling operation through the pass formed by the rolls in and H. The rolls [3 and I4 are mounted on short axles [5 which are not driven and are connected by means presently to be described to a pin It on a ram 11.

Ram I! is movable in a hydraulic cylinder l 8 in a direction which causes both rolls I3 and I4 to approach the blank B and to make contact with its circumference. For movement of the rolls l3 and M in the opposite direction, ram I1 is hollow at one end, so as to form there a hydraulic return cylinder l9, which co-operates with a stationar ram 20.

The connection between the rolls I3 and M respectively and the pin It comprises pairs of oppositely arranged links 2| and bell-cranks 22, joined together by pins 2|. The bell-cranks 22 have pivot pins 22, and carry at their free ends the axles l5 on which the rolls [3 and It are mounted. The free arm of the bell-crank for roll I3 consists of two separate sections 22! and 222, hinged together at 23, while the free arm of the bell-crank for roll it is in one piece. Section 22I is formed with a boss 24 on to which a relief valve 25 for the release of pressure fluid from cylinder I8 is mounted. The valve has a closure member 26 which is normally held against a seat 21 by a spring 28, but can be lifted from the seat 21 by an actuating rod 29. The latter is normally held apart from member 26 by a spring 30 which is stronger than spring 28. Rod 29 has, further, a collar 3i which is normally held by spring 30 in engagement with a flange on bell-crank section 22 I. Bellrcrank section-222 has also a flange which causes rod 219; tobe displaced against the action of spring 39, and thereby to lift closure member 2'6 from its seat 27, thus opening relief valve as soon as section 222 is swung away from the blank B following the expansion of the latter during the rolling operation.

Closing of valve 2'5 can be effected without moving rod 29 back into its former'position by the action of bell-crank section 225, which, when moved away from blank B, will cause valve seat 2! to approach closure member 26. This move-- ment of section 22! takes place when the ram IT is displaced to the right in Fig. l by the outward. movement of roll [4, upon the release of pres-- sure fluid from cylinder 18.

Valve 25 has two ports 32 and 33 which, by means of flexible pipes 34 and 35 respectively are, connected to the cylinder l8 and to an exhaust line 38. In the position of Fig. 1, valve 25 is closed and the ports 32 and 33 have, therefore, no communication with each other. Ram H is thus hydraulically locked against movement to the right in Fig. 1, but will be caused to travel in that direction upon. the expansion of the blank B, whereby rolls it and H! are moved' aside and the" relief valve 25 operated as describedbefore.

Relief valve 25 forms part of a hydraulic pressure system which includes circuits for supplying and discharging pressure fluid to and from the cylinders It and i9 respectively. These circults are controlled froma valve blocs as connected to a pressure fluid supply line 37, an. ex haust line 35, a line 39 leading to cylinder 38, and a line 49 leading to cylinder P3. The block 36 has a number of valves ii to it which are operated by means of a levers? and rock shaft 4i in anonventional manner, the" different positions of lever 45, and thus of the valves controlled thereby, being apparent from the diagrammatic illustration of Fig. l. The block 36 comprises, furthermore, a pressure limiting valve 48 and a suction valve 49, both in circuit with cylinder 1! 9.

Before starting operations, the rolls l3 and hi are moved aside, so that a blank B can be placed over the working roll H. The valve actuating lever 46 is now moved into the close position, pressure water is thereby supplied to cylinder l8 and discharged from cylinder I9, so that ram I'I travels to the left in Fig. 1 and causes rolls f3 and It to move towards the blank B. It will be noted here that the two rolls l3 and 14 are not entirely symmetrically positioned relative tothe centre line through the axes: of the rolls f6 and H inasmuch as the roll I3 is slightly further away from that line than the roll i4, so that there will be a small clearance between roll [3 and blank B when the roll 14 touches the blank. After the roll 14 has made contact with the blank B, the lever to is moved into the automatic position, whereby all valves in block 36 are closed, excepting valve is. Cylinder 18 is thus placed in communication with exhaust line 33 whenever the ports 32 and 33 are placed in communication with each other by the opening of the relief valve 25 in the afore-described manner.

The rolling operation proper is now carried out and the wall thickness of the blank B gradually reduced by the combined action of the rolls l0 and H, the diameter of the blank B increasing at the same rate as its wall thickness decreases. The clearance between roll l3 and blank B permits the latter to expand freely first and to shift towards that roll while being in pressure contact with roll l4 due to the action of the pressure fluid in cylinder [8. On further expansion, blank B contacts roll l3 and moves it aside, whereby valve 25 is opened as described before, and pressure fluid is released from cylinder Hi. This enables roll [4 to give way to the expanding blank, and at the same time displaces ram 11 to the right in Fig. 1 through the connection between roll [4 and ram H' by parts 2 1V and 22. Displacement, of ram ll causes valve 25 to be closed again, as described before. Roll H! is thus locked temporarily in position again, and the spreading of the blank takes placetowards roll l3 which is moved aside, opens valve 25 and releases pressure fluid from cylinder 18, thereby permitting roll 14 to give way to the spreading blank, closing valve 25 again, and so on until the blank has been rolled to its desired thickness.

The movements. of .the rolls [3 and M which cffectthe opening and closing of valve 25 are very small, and follow each other continuously and in quick succession. It will also be observed that the chief function of roll I3 during the rolling process proper is to. control the operation of valve 25, without transmitting any appreciable pressure to the blank B, the. guiding action being; applied mainly by'roll. l 4..

The suction valve 49 serves to establish come municaticn between cylinder [9. and exhaustline I lever lt has been moved to stop, whereby all valves in control block 36 are closed, and relief valve 2%: is put out of action. The rolls l3- and M are thereby locked in their respective positions and are both firmly held in contact with the blank during the rounding-off passes.

After rolling has been terminated, the lever 48 is moved into the open position. Valves 4!, 43 and Q5 are thereby opened and valves 42 and 44 closed. Pressure fluid is thereby admitted to cylinder l9 and discharged from cylinder Ill. The rolls [3 and Hi are thereby caused to swing opento make room for the removalv of the finished blank and for the insertion of a fresh one.

Fig. 2 shows another embodiment. of a rin rolling mill acccording to the invention, in which the same principle as in. the embodiment of Fig. l is used for automatically controlling the blankguiding means. The mill. according. to Fig. 2-

has outer and inner working. rolls 60 and BI respectively, corresponding to the rolls Ill and H of the embodiment of Fig. l, and, further, rolls E3 and G l corresponding to the rolls [-3 and. M.

site to that carrying roll 64 is a casing 74 of a.

relief valve 15 which has two ports 16 and 71 connected to cylinder H by a flexible pipe 18,

and to an exhaust line, not shown, by a flexible pipe "is respectively. Cylinder [3 is constantly connectedto. .a line 89, and always suppliedwith; hydraulic pressure fluid. In view of the-greater;

area of cylinder 'H,'however, the ram 18' is normally urged towards the left in Fig; 2.

Movement of the ram in the opposite direction is effected by placing the ports 16 and 11 in communication with each other through opening relief'valve l5 and thereby releasing pressure fluid fromrcylinder' H. The relief valve has the same function to fulfil as the relief valve of Fig; 1,-and is therefore similar to the latter in its essential features. It has a closure member 81 normally held against a seat 82 by a spring 83, but adapted to be lifted from the seat by an actuating rod 84 (see Fig. 3). Rod 84 is connected by a link 85 to an S-shaped lever 86 pivoted at its centre about a fixed pin 8'! situated in the centre line of the axes of the rolls 60 and 61, the S-shaped lever being in turn connected by a link 88 to lever 66. Inserted'between a nut 89 on rod 84 and a cover plate 98 of valve casing 14 is aspring 91' which normally keeps rod 84 out of engagement with closure member 8!.

It will be apparent from the foregoing, and from an inspection of Fig. 2, that anyoutward movement of roll 64 will cause valve casing 74 to be displaced towards the left in Fig. 2 relative to rod 84, which remains stationary at this stage, with closure member 8| following the movement of the casing 14 due to the action of spring 83. In this way, closure member 8! is caused to abut against rod 84 and to be liftedfromits seat 82, placing ports 16 and T1 in communication with each other, whereby pressure fluid is released from cylinder 1 1.

Without moving casing 14 back into it former position, relief valve 15 can be closed by displacing rod 84 to the left in Fig. 2 and thus allowing closure member 81 to return to its seat 82 under the action of spring 83. This is effected by the aforedescribed connection between rod 84 and lever 66, whereby displacement of rod 84 to the left of Fig.2 takes place when the lever 66 is rocked about its pivot pin 68 in a clockwise direction upon the release of pressure fluid from cylinder 1 I.

Relief valve 15 forms part of a hydraulic pressure system which includes circuits forsupplying and discharging pressure flu d to and from the cylinder H. These circuits are controlled from .a valve block 92 connected to a pressure fluid. supply line 93, and exhaust line 64 and a line 95'leading to cylinder II. The block 92 has valves 98 and 91 which are operated by means of a lever98 and a rock-shaft 99 in a conventional manner, the different positions-of lever 98, and thus of the valves controlled there by, being apparent from the diagrammatic illustration of Fig. 2.

The operation of the blank-guiding means of Fig. 2 is substantially similar to that of the means shown in Fig. 1 which have been described before.

Before starting operation, the rolls 63 and 64 are moved aside so that a blank B can be placed over the inner working roll 61. The actuating lever 88 is then moved into the close position, whereby valve 96 is opened and valve 91 closed. Cylinder H is filled with pressure fluid from line 93, so that ram 16 can overcome the constant pressure in cylinder 13 and is displaced to the left in Fig. 2, swinging lever 66 about its pivot pin 68 in a counter-clockwise direction. At the same time, lever 61 is rocked in a clockwise direction through the afore-described link and lever connection comprising the parts 85 to 88 and through the action of spring 91 which moves casing 14 to the right when rod 84 is moved to of the relief valve by an electrical control.

the right. Thus, both rolls 63 and 64 are caused to move towards the blank B.

In the same way as in Fig. 1, the two rolls 63 and 64 are not entirely symmetrically positioned relative to the centre line of the axes of the rolls 68 and 6 l, inasmuch as the roll 84 is slightly further away from that line than the roll 63, so that there will be a small clearance between roll 64 and blank B when the roll 63touches the blank. After the rolls 63 and 64 have been so' far approached to the blank B that the roll 63 makes contact therewith, thelever 98 is moved into the stop position whereby both valves 98 and 91 are closed and the supply of pressure fluid t cylinder ll cut off.

. The rolling operation proper is now carried out, and the wall thickness of blank B gradually reduced by the combined action of the rolls 60 and 6|, the diameter of the blank increasing at the same rate as its wall thickness decreases. The clearance between the roll 6-4 and blank B permits the latter to expand freely first and to shift towards that roll while being in pressure contact with roll 63, due to the hydraulic force exerted on ram 18. On further expansion, blank B contacts roll 64 and moves it aside, whereby lever 6! is moved in a counter-clockwise direction in Fig. 2. Valve 15 is then opened as described before and pressure fluid released from cylinder 1|. This enables roll 6 3 to give way to the expanding blank, thereby swinging lever 66 in a clockwise direction and closing valve 15 through the'link connection B8. Roll 63 is thus locked temporarily in position again and the spreading of the blank takes place towards roll 64 which is moved aside, opens valve 15 and releases pressure fluid from cylinder ll, thereby permitting roll 83 to give way further to the spreading blank, closing valve 15 again and so on, until the blank has bee rolled to its desired thickness.

Similar to the case of Fig. 1, the movements of the rolls 63 and 64 which effect the opening and closing of the valve 14 are very small and follow each other continuously and in quick succession. The chief function of roll 64 during the rolling process proper is to control the operation of valve 15 without transmitting any appreciable pressure to the blank B, the guiding action being applied mainlyby roll 63. y

After rolling has been terminated, the lever 98 is moved into the open position. Valve 96 is thereby closed, and valve 9! opened,- whereby pressure fluid is discharged from cylinder ll into line 94. This causes theram 78 to travel to the right in Fig. 2, whereby .both rolls and 64 .are swung open to make room for the removal of the finished blank, and for the insertion of a fresh one.

It is to be understood that the invention is capable of other embodiments than those shown and described here. It is, for instance, within the scope of the invention to substitute the mechanical control of the opening and closing movements In this case, the relief Valve 25 or 15 could be arranged at a point distant from the mechanical connection between the hydraulic ram I! or 10 and the roll l3 and I4 or 6-3 and 64 respectively and remain stationary, so that flexible pipes for the supply and discharge of pressure fluid would no longer be required. The mechanical connection between the hydraulic ram 11 or 10 and the rolls l3 and Hi or 63 and 64 respectively would be provided with electrical contact means which would be opened and closed for energising or denereis ns a solen id cont ollin the relief valve! the opening and closing of the contact means being effected by means similar to those effecting the opening and closing of the relief valve 25 and r spectiv ly n he em odiments olescribed before.

What I claim is; 1. A, ri ro mill hav n an inner d an. outerworking roll adapted to reduce. the-wall thickness of annular blanks while allowing the blanks to increase. in diameter at, the sa e time, guide rolls adapted to engage the outer periphery of a. blank during a, rolling operation, a hydraulic cylinder and ram unit for moving said guide rolls into engagement with a blank, automatically op-.

crated control means for alternatively reducing and re-establishing in quick succession the fluid pressure in said hydraulic cylinder while said guide rolls are in contact with a blank, and means connected to said control means movable by change in diameter of said blank to operate said control means.

' 2. A ring rolling mill having an inner and an outer Working roll adapted to reduce the wall thickness of annular blanks while allowing the blanks to increase in diameter at the same time, guide rolls adapted to engage the outer periphery of a blank during a rolling operation, a hydraulic cylinder and ram unit for moving, said guide rolls into engagement with a blank, an automatically operated relief valve for alternately reducing and rte-establishing in quick succession the fluid pressure in said hydraulic cylinder while said guide rolls are in contact with a blank, and means operating said relief valve in response to blank diameter change.

3. A ring rolling mill having an inner and an outer working roll adapted to reduce th wall thickness of annular blanks while allowing the blanks to increase in diameter at the same time, guide rolls adapted to engage the outer periphery of a blank during a rolling operation, a hydraulic cylinder and ram unit for moving said guide rolls into engagement with a blank, a resilient mechanical connection between said ram and one of said guide rolls permitting a short displacement of one guide roll away from the centre of a blank independently of the other guide roll, an automatically operated relief valve for alternately reducing and re-establishing in quick succession the fluid pressure in said hydraulic cylinder while said guide rolls are in contact with a blank, and actuating means for opening said relief valve in response to a displacement of said guide roll away from the. centre of a blank.

4.. A rin rollin mi l ha in n ne nd an outer working roll adapted to reduce the wall thickness of annular blanks while allowing the blanks to increase in diameter at the same time, guide rails adapted to e age the out r er ph r of a. blan durin a ollin one a c a hydr c. cylinder and ram unit for moving saidrguide rolls into engagement with a blank, a resilient me-.-' chanical connection between said ram and one of said guide rolls permitting a short displacement of a guide roll away from the centre of a blank independently of the other guide roll, said con nection comprising two elements pivoted to each other, and spring means normally urging one of said elements away from the other, an automatically operated relief valve for alternately reducing and re-establishing in quick succession the fluid pressure in said hydraulic cylinder while said guide rolls are in contact with a blank, and aotu ating means for opening said relief valve in re-. sponse to a displacement of said guide roll away from the centre of a blank.

5. A ring rolling mill having an inner and an outer working roll adapted to reduce the wall thickness of annular blanks while allowing the blanks to increase in diameter at the same time, a pair of guide rolls adapted to engage the outer periphery of a blank during a rolling operation, a hydraulic cylinder and ram unit for moving said guide rolls into engagement with a blank, a resilient mechanical connection between said ram and one of said guide rolls permitting a short displacement of a guide roll away from the centre of a blank independently of the other guide roll, a rigid mechanical connection between the other of said guide rolls and said ram, an automatically;

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 416,797 Munton Dec. 10, 1889 416,798 Munton v Dec. 10, 18,89

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