US3673840A

US3673840A - Cold rolling pipe roller type rolling stand

Info

Publication number: US3673840A
Application number: US720A
Authority: US
Inventors: Alexandr Ivanovich Tselikov; Vsevolod Vladimisovich Nosal; Vadim Anatolievich Verderevsky
Original assignee: VNI AND PK I METALL MASH
Current assignee: VNI AND PK I METALL MASH; VSESOJUZNY NAUCHNO ISSLEDOVATELSKY AND PROEKTNOKONSTRUKTORSKY INST METALLURGICHESKOGO MASHINOSTROENIYA
Priority date: 1970-01-05
Filing date: 1970-01-05
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: CA952744A; CA953953A; US3680345A

Abstract

A rolling stand with a reciprocating rigid frame carriage coupled to a vertical rocking beam lever for drive reciprocation. The carriage has eight rollers, cooperating with rigid tracks, disposed to maintain the carriage against pitch. A thick walled rolling reduction head is removably and securely mounted in the carriage. The head contains working rollers maintained in a resiliently biased balanced disposition in a slide race or separator so the rollers bear against former tracks rigidly secured against axial shift in the reduction head. The separator is reciprocable and its movement is synchronized, via a connection to the rocking lever, with the reciprocation of the head so the separator follows the movement of the rollers relative to the head. A wedge mechanism under the former tracks enables radial adjustment of the tracks.

Description

United States Patent Tselikov et al. 1 July 4, 197 2 54] COLD ROLLING PIPE ROLLER TYPE 3,411,336 11/1968 Wadleck ..72/2o9 ROLLING STAND 1,890,803 12/1932 Coe ..72/208 [72] Inventors: Alexandr lvanovich Tsel ikov; Vsevolod primary Examine, Mi|ton Mehr Vladrmrsovrch Nosal; Vadlm Anatollevich s h N l N l Ni g K Verderevsky, all of Moscow, USSR.

[73] Assignee: Vsesojuzny Nauchno lssledovatelsky and [57] ABSTRACT proqkmokmstmkmfsky [minute Metal A rolling stand with a reciprocating rigid frame carriage coulurglcheskogo Mashmostmemya, Moscow, pled to a vertical rocking beam lever for drive reciprocation. The carriage has eight rollers, cooperating with rigid tracks,

[22] Filed: Jam 5, 1970 disposed to maintain the carriage against pitch. A thick walled rolling reduction head is removably and securely mounted in [21] Appl. No.: 720 the carriage. The head contains working rollers maintained in a resiliently biased balanced disposition in a slide race or 52 U.S.Cl separator so the rollers bear against former tracks rigidly E d Int CI secured against axial shift in the reduction head. The separa- [58] Field of Search 'b 214 210 tor is reciprocable and its movement is synchronized, via a connection to the rocking lever, with the reciprocation of the 56 head so the separator follows the movement of the rollers rela- 1 References Cited tive to the head. A wedge mechanism under the former tracks UNITED STATES PATENTS enables radial adjustment of the tracks.

2,161,065 6/ l 939 Krause ..72/209 36 Claims, 19 Drawing Figures PATEN'E'EDJUL 41972 3,673,840

SHEEI 10$ 7 INVENTORS ALEXANDR IVANOVICH TSELIKOV VSEVOLD VLADIMISOVICH NOSAL VADIM ANATOLIEVIGH VERDEREVSKY ATTORN PATENTEDJULM 1912 3, 673.840

SHEET 2 or 7 INVENTORS ALEXANDR IVA ICH TSELIKOV OLD VLA OVICH AL M ANATOLIEVICH VE EVSKY ATTO PATENTEDJUL' 41972 3,673,840

FIG 3 INVENTORS ALEXAN DR IVANOVICH 'ISELIKOV VSEVOLD VLADIMISOVICH NOSAL VADIM ANATOUEVICH VERDEREVSKY ATTORNE S PATEiHiZDJULM 1572 SHEET 8 0F 7 IN VEN TORS ALEXANDR IVANOVICH TSELlKOV VSEVOLD VLADIMISOVICH NOSAL FIG. I0 VADIM ANATOLlEVlCH VERDEREVSKY fl%am %%4%MQ ATTORN YS PLKTENTEDJULd m2 sum 7 or 7 3,673,840

ANGLE IN DEGREES INVENTORS ALEXANDR IVANOVICH TSELIKOV FIG [7 VSEVOLD VLADIMISOVICH NOSAL VADIM ANATOLIEVICH VERDEREVSKY wwwww y/ ATTORNEYS COLD ROLLING PIPE ROLLER TYPE ROLLING STAND CROSS-REFERENCE TO RELATED APPLICATION The inventive subject matter herein is disclosed but not claimed in a related US. application Ser. No. 529, filed Jan. 5, 1970, directed to an overall mill structure and method of cold rolling thin walled pipe.

BACKGROUND OF THE INVENTION Most pipe mill rolling stands are of the Pilger roll type although mill rolling stands with rollers rolling along former tracks or gibs to provide the reductionof thickness of pipe walls were known prior to the present invention. Pilger type roll stands are massive, expensive and require substantial amounts of time for installation, removal and replacement because of the critical correlations between varying roller former grooves. The rolls are large and require heavy load resisting bearings and complex synchronizing mechanism.

On the other hand, roller type roll stands are not as massive and do not require bearings for the simple rollers which use straps or bars as tracks which provide the roll reduction movement.

Roller type roll stands for cold rolling thin wall pipes have been previously known and constructed and some initial constructions were disclosed in the text "Cold Rolling Pipe Mills" by Shebakin, Yu. A. et al., Metalurgizdat 1966 published in the Soviet Union. Since that publication, the roller type roll stands as well as the drive linkage for cold rolling thin walled pipes have undergone considerable development with resultant important improvements in the drive linkage as well as the roll stand and its components.

SUMMARY The present invention pertains to improvements in the carriage of a'roller type of roll stand to provide a simple yet rigid carriage structure with load and pitch rollers on a lengthened wheelbase over the prior art roll stands as well as an improved drive connection. The roller head has been made in a simplified manner with roller, strap track, separator and track adjustment components assembled in a thick-walled steel cylinder which has enabled a very simple means of removably rigidly locking the head in the carriage. An improved rocking lever assembly has enabled a better balanced drive force to the roll stand from the power equipmentas well as reducing the lateral and vertical dimensions of the pipe mill at the roll stand end. An improved, and more reliable, parallel roll stand end. An improved, and more reliable, parallel roll stand and roller separator linkage has been developed in connection with the new carriage and new rocking lever structure. Also a novel spring balancing arrangement has been provided for mounting the rollers in their separator.

The above reiterated new developments and improvements in roll stand structure and operating linkage constitute the principal inventive aspects of the roll stand invention.

Further novel features and other objects of this invention will become apparent from the following detailed description, discussion and the appended claims taken in conjunction with the accompanying drawings:

BRIEF DESCRIPTION OF DRAWINGS A preferred structural embodiment of this invention is disclosed in the accompanying drawings, in which:

FIGS. 1a and 1b, viewed together will be referred to as FIG. 1 which illustrates in side elevation a pipe mill incorporating a roll stand and operating linkage made in accord with this invention;

FIGS. 2a and 21;, also viewed together will be referred to as FIG. 2, illustrating in plan view the pipe mill seen in FIGS. la and 117;

FIG. 3 is a diagrammatic representation .of the power and driven transmission mechanism in the mill shown in FIGS. 1 and 2;

FIG. 4 (on sheet 2) is an illustrative drawing of the Geneva feed used in the feeding and turning mechanism;

FIG. 5 is a sub-assembly side elevation of the roller carriage and attached rocking lever, the lever being partially broken away;

FIG. 6 is a vertical section view taken on line 6-6 of FIG. 7, showing internal details of the rolling stand as well as added details of the operating rocking lever and connecting links;

FIG. 7 is an enlarged, partially sectioned, rear end view of the roller carriage, the rocking lever and operating links;

FIG. 8, drawn to a smaller scale than FIG. 7, is a front end view of the roller carriage with one ofthe carriage support rollers shown in section;

FIG. 9, a vertical section view taken on line 9-9 of FIG. 6, illustrates interior details of the roller carriage;

FIG. 10 is an enlarged detail section of the separator cage, shown in smaller scale in FIG. 6, illustrating the spring balanced roller mounting;

FIGS. 11 and 12 are somewhat diagrammatic views, respectively showing an arrangement using three rollers and an arrangement using five rollers;

FIG. 13 is a pictorial perspective view showing just the three rollers and their strap tracks;

FIG. 14 is an exaggerated contour view of the roller track profile on a strap;

FIG. 15 is pictorial side view illustrating the the rolling operation;

FIG. 16 is a front view of a roller drawn to scale and used to illustrate the degree of rolling out of the edge of the roller when a 2 mm reduction in diameter from a stainless steel pipe blank to finished pipe is being accomplished; and

FIG. 17 is a graph used in determining rolling out angles for rollers used in cold rolling of stainless steel pipe.

SPECIFIC DESCRIPTION With reference to FIGS. 1 and 2, a pipe mill will be generally described in terms of its main mechanisms and details of the roll stand and its operating linkage will be described hereinafter with reference to FIGS. 5-17, most of which are reproduced from working drawings and can be scaled for relative dimensions. As the general description proceeds, by referring to the diagrammatic illustration of FIG. 3, the functional interrelationship of the mechanisms can be kinematics of better understood.

The pipe mill 50 disclosed in the drawings has been used in producing thin-walled pipe with CD. of from '8-15 mm. The mill is assembled from a number of sub-assemblies supported by the mill floor or foundation 52. Main power is furnished by an electric drive motor 54 which can be located in a well 56 under the other pipe mill components which are supported on several heavy steel I-beams 58 resting on and secured to the mill floor. A rolling stand 62 is located at the front end (right hand end of the drawings) of the mill and, with the rocking lever assembly 64, is mounted in a front mill housing 66 in a manner enabling the rolling stand to be reciprocated back and forth by the rocking lever, as will be hereinafter described in more detail. The front housing contains heavy structural steel framework secured to the I-beam bed.

At the left-hand end of the mill, a rear housing 68, also secured to the l-beam bed, contains feeding and turning gear mechanism 70, a part of the drive'path from motor 54 to the mandrel clamp assembly and the floating blank chuck 80. The front and

rear housings

66 and 68 are rigidly secured to and provide end support for the intermediate frame or mill table 72 which includes a heavy cast rear end brace 74 and parallel longitudinal beams 76 to which are fastened parallel channel track slideways 78 forming guide tracks for a floating" blank feed chuck 80 which travels from a position adjacent the rear housing to a location adjacent the front housing in feeding a pipe blank to the rolling stand.

Seen between the main motor 54 and front housing .66 is a third housing 82, offset to one side but rigidly secured to the I- beam bed. Housing 82 contains reduction and drive transfer gearing from the motor drive to the rocking lever and the blank feed mechanism.

At the extreme rear end of the mill, the input end, is the mandrel rod clamping mechanism 84 which is rigidly fastened to the rear wall of housing 68 by a heavy welded steel cantilever support 86.

Looking again at the front end of the mill as shown in FIG. 2, an intermediate blank clamp assembly 88 can be seen near the rear end of the rolling stand housing 66. The operating solenoid for the intermediate clamp is located in the box-like housing 90.

Near the left hand side of FIG. 1, a second drive motor 92 is secured under the table on a support frame 94. Auxiliary motor 92 is used for speeded up feed-in and return movement of the blank feed chuck 80.

Suitablylocated along the length of table 72, one or more welded steel stands 96 provide rigid support for the table, as necessary. Appropriate sheet metal cowling 98 can enclose the sides of the intermediate frame or table area. Blank pipe supports 100, which can be shifted and removed, are used along the table to help support the mandrel spindle and blank, in a manner well-known in the pipe mill art.

Main and auxiliary

mill control panels

102 and 104 are located on the side of the table near the rear and front ends and include various electrical control switches and indicator lights to operate and indicate mill condition.

The drive mechanism is bestunderstood with reference to- FIG. 3 with supplemental reference to FIGS. 1 and 2. Drive power is derived from the two

electric motors

54 and 92. The main motor 54 is a three-speed asynchronous electric motor which, with an electromagnetic brake 106, is installed on an adjustable base plate 108 (FIG. lb) for purposes of adjusting the drive belt tension. A multiple sheave V-belt drive pulley 110 and a brake drum 112 are installed on opposite ends of theelectric motor shaft 114. Switching between desired ones of the three speeds of the electric motor speed is carried out, as required, by conventional control circuitry via one of the

control panels

102 or 104. By providing variable motor speed, greater versatility is enabled in cold rolling operations, per mitting the: pipe mill to roll thin-wall pipes made from a number of different metals and alloys. 1

Drive power istransmitted from main motor 54 through driving pulley 110 and multiple V-belts 116 to a large diameter multiple sheave driven pulley 118 on an input shaft 120 to the reduction transmission 82. Once the mill is in normal operation, drive power for the rolling is through the input shaft 120 and within the reduction transmission is transferred via gear 122 to a shifting gear cluster 124 (which is splined to a transfer shaft 126) thence via meshed speed reduction gears 128 and 130 to a crankshaft 132. Secured on the end of crankshaft 132 is a crank wheel 134 carrying a crank pin 136 and connected between the crank pin and the rocking lever assembly 64 is a massive connecting rod 138 with its line of thrust being disposed under and in alignment with the pipe feed-in axis.

A second power output shaft 140 is connected to the crankshaft 132 via a set of

bevel gears

141, 143 and projects rearwardly from the reduction transmission 82 to provide primary drive power to the blank feeding and turning mechanism 70.

The

crank mechanism

134, 136 furnishes the drive power to cause the reciprocal (see-saw) displacement of the rolling stand 62 by means of the. swinging lever assembly 64. Inside the reduction gear housing, a pneumatic motor 142 connected to a shift lever 144 is used to shift the gear cluster 124 to mesh with driving gear 146 to furnish a special high speed feed-in drive for moving an initial pipe blank up to the rolling stand.

Drive power for the blank feeding and rotating mechanism 70 is accomplished by means of the main electric motor through its V-belt transmission, reduction gearing 82, and the transmission output shaft 140 which is drive coupled to a long drive shaft 150 coupled at its rear end to an input shaft 152 for the blank feeding and turning mechanism 70.

The mill rolling operation requires intermittent feeding and turning of the pipe blank, accurately correlated with a specific increment of the rocking cycle of the rolling stand 62 (its extreme rear position). This accurate correlation is enabled by means of a single geneva (Maltese Cross") drive transfer assembly 154. Geneva drive derives from the continuously rotating input shaft 152 through gear 156, an idler gear 158 and a gear 160 drive connected to the geneva drive input shaft 162. Shaft 162 carries and rotates the geneva crank 164. A six slot Maltese Cross wheel 166, such as used in the present invention, is shown in FIG. 4 and is subjected to periodic stepped rotation by the crank 164 through its roller earn 168. When not being step driven by the crank the Maltese Cross" is locked by a conventional locator or blocking plate 170. Crank 164 and locator plate are continuously rotated at a number of revolutions per unit time equal to the number of double passes or cycles of the rolling stand 62. When the rolling stand is approaching its extreme rear position, the geneva crank roller cam 168 enters a slot of the cross 166 and rotates it one step, which with the six slot cross is 60'? The rotation of the cross is terminated at the beginning of the straight rolling pass of ther stand.

The geneva output. cross 166 is drive connected to a shaft 172, to which is splined an axially fixed gear cluster 174 which provides a selected one of two angular amounts of incremental rotation of the blank rotating drive shaft 176 (58l0' or 72) and also causes difi'erent numbers of rotations of the feeding screw drive shaft 178. The gear cluster 174 includes three

gears

180, 182 and 184 which rotate as a unit and two of the gears, and 182, are used in conjunction with the shifting gear cluster 186 splined to turning shaft 176 to provide the two different increments of rotation (58l0' or 72), for reasons which will become apparent as the description proceeds. Gear cluster 186 is shifted by a gear shift lever 188 (FIGS. 1a and 2a) on the top of the rear housing 68.

The blank feed chuck drive is via a step up gearing from gear 184 of the gear cluster 174. Gear 184 meshes with a two gear idler cluster 190 joumalled on the feed shaft 178, and

drive is transmitted through a shiftable gear cluster 192 splined to transfer shaft 194, thence through a second shiftable three gear cluster 196, also splined to transfer shaft 194, to a selected one ofa three gear cluster 198, rotatably mounted on and operable to drive the feed screw shaft 178 as will be' described hereinafter. The shiftable two gear cluster 192 is selectively meshed with one of the gears on cluster 190 and the shiftable three gear cluster 196 is selectively meshed with an associated one of the gears on the cluster 198 by meansof the two gear shift levers 200 and 202 (FIGS. 1a and 2a) located on the side of rear housing 68, providing six step-up gear ratios in the drive to the feed screw drive shaft 178 during each cycle of rolling stand reciprocation.

HIGH SPEED FEED SCREW OPERATION Under certain conditions, high speed continuous rotation of feed screw drive shaft 178 is desired, e.g., feed-in of a pipe blank when the first blank is introduced at the start of mill operation and return of the floating chuck assembly 80 to its rear start position when a succeeding pipe blank is fed into the mill. The auxiliary electric motor 92 with conventional reversing controls (not shown) furnishes the drive power for high speed feed shaft rotation. The auxiliary high speed power drive train is via the auxiliary motor shaft 204 which is drive connected through a brake 206 (FIG. 1a) to an input shaft 208 joumalled in the rear mill housing 68. From input shaft 208 the auxiliary power is transmitted through a gear 210 on the shaft 208 thence through an idler gear 212 to a friction clutch input gear 214 rotatably joumalled on the feed screw drive shaft 178 adjacent the feed shaft gear cluster 198. Located on and slidably splined to feed screw shaft 178 is a shiftable coupling member 216. One face 218 of coupling 216 has jaw clutch teeth which, when the coupling is shifted to one position (normal speed), will positively mesh with the jaw clutch teeth on a clutch face member rigidly secured to the gear cluster 198. This condition enables feed screw drive derived from the main motor through the incremental geneva drive 154. The other face 222 of coupling member 216 is a conical friction surface which can mate with an internal conical surface of a coupling face 224 on the clutch input gear 214.

Coupling member 216 is selectively shifted from one to the other of the two positions by a shifting lever assembly 226 actuated by a pneumatic motor 228 controlled by solenoid operated valves 230, in turn controlled through suitable control circuitry.

The ends of the blank turning shaft 176 project from the front and rear of the rear mill housing 68, being offset to one side from the axis of the pipe blank path, as seen in FIG. 2a, and it is aligned with and its front end is drive coupled with a long, blank turning shaft 240 extending substantially the length of the mill. Shaft 240 is journalled near its rear end in a bearing block bracket 242 and at its front end in a bearing assembly on the intermediate blank clamp assembly 88. The long, blank turning shaft projects through the floating chuck assembly 80 and is slidably drive coupled thereto.

The projected rear end of turning drive shaft 176 is coupled with an aligned mandrel clamp turning shaft 244 enabling an incremental turning of the mandrel clamp (as well as the mandrel spindle) conjointly with turning of the blank.

The feed screw drive shaft 178 projects from the front side of the rear mill housing and is aligned and drive coupled with a long, feed screw 246 extending substantially the length of the mill and disposed directly under the axis of the pipe blank feed path. The feed screw 246 is joumalled against axial movement in tapered roller thrust bearings located in the rear bearing block bracket 242 and, at its front end, in the intermediate blank clamp assembly 88. The feed screw 246, intermediate its front and rear journal portions, is threaded and is turned through a feed nut in the base of the floating chuck assembly 80, so that rotation of the feed screw 246 will feed the floating blank chuck assembly forward or backward.

In the cold rolling pipe mill operation being described, a mandrel head 252 (FIG. made from steel and shaped to conform with the desired inner diameter of the finished pipe is axially maintained in a predetermined axial position disposed within the rolling stand 62. A long mandrel spindle or rod 250 extends from the mandrel clamp assembly, which securely clamps the rear end of the rod, along the feed path axis, through the floating blank chuck 80, along the length of the table 72, through the intermediate clamp 88 and into the rolling stand 62 where it carries the mandrel head 252.

ROLLING STAND The rolling stand of the present invention, details of which are shown in FIGS. 5-17, is an improvement over a prior art roller type of rolling stand which has been used in the Soviet Union to roll thin-walled pipes. Most thin-walled pipes or tubes are produced by cold rolling on special Pilger mills which use rolls having complex working pass grooves of changing profile or by multi-draft drawing over a short or long mandrel. Tubes of 17 to 20 mm minimum diameter can be produced by a cold rolling process providing up to 75-80 percent reduction per pass. In West European countries it has been regarded inexpedient to roll tubes with wall thicknesses less than 1 mm.

The improvement of the working tool calibration pattern enabled the Soviet Union to efi'ectively roll tubes having walls down to 0.6 mm thick on the Pilger roll-type (called so as to be distinguished from the roller-type mills). Any further reduction in the wall thickness of tubes rolled on the roll-type mills involves great difficulties resulting from excessive elastic contact compression of the working tool with roll diameters specified. As a result, specific roll forces are increased which lead to a much greater degree of sticking of metal particles to the working tool and resultant deterioration of the quality of the finished tubes surface. The reduction of roll diameters in such prior art mills has been limited by the load-carrying capacity of the roll bearings. The complexity involved in accurately machine working the passes of changing profile also makes it difiicult if not impossible, to obtain thinner walled tubes on the Pilger roll-type mill due to increased likelihood of transverse non-uniformity of the wall thickness.

In the development of new mills (of which the present is an improved version) for rolling super thin-walled tubes (tubes with wall thicknesses less than 0.02 of the outside diameter), instead of using two complex changing profile former surfaces in large diameter work rolls of the Pilger roll-type tube mill, three or more small diameter rollers are employed, these rollers having grooves of constant profile not changing around the circumference, and either use no axle or use short integral rolling shanks whose diameter approaches that of the bottom of the working groove.

Instead of using back-up rolls as used in some cluster mills, special-type contoured tracks on straps or gibs support the cylindrical stub shank journals of the work rollers. The profile of the strap track provide the amount of reduction movement by the rollers and therefore, function both as bearings and formers for the work rollers. The straps or gibs are mounted in a thick-walled tube of the mill rolling stand carriage, which is reciprocated by the crank-and-link drive of the mill.

The work rollers, held against the straps, are mounted in a separator. With the mill running idle, the separator is moved by a kinematic lever system inside the working carriage at a speed corresponding to the velocity of the rollers as they roll along the tube axis during the rolling process to synchronize the location of the rollers in the rolling head.

Referring initially to FIGS. 5-8, the rolling stand 62, followed by details of the rocking lever assembly 64, will now be described. The rolling stand is of primary importance to successful mill operation and includes a heavy, rigid roller head 680 secured in a carriage 682, the carriage serving as a crosshead and including a yoke post 684 to which a connecting rod 686 from the rocking lever assembly 64 is connected.

The rolling stand carriage 682 is fabricated from rigid steel plate and its frame consists of two

flat side beams

688 and 690, a rear wall 692 and a front wall 694 welded as at 696 and 698 (as shown in FIGS. 7 and 8) to respective areas of the side walls. The rear wall is located approximately at the mid point of the side walls. Both the rear wall 692 and the front wall 694 have circular openings 700 and 702, respectively, which are aligned and releasably receive and mount the rolling head 680. Immediately adjacent the upper front side of rear wall 692 an arcuate saddle 704, made from steel plate, is welded to the rear wall and upper edges of the two

side plates

688 and 690. The inner surface of saddle 704 is coextensive and coaxial with the upper periphery of the circular openings 700 and 702. Tire hereinbefore described joke post 684 is welded to the top center of saddle 704 and to the top edge of rear wall 692 and, with the saddle, constitutes the drive yoke by which the carriage is reciprocated through its double passes.

The rolling stand carriage 682 is installed in the mill on eight rollers 706-713, roller bearing mounted on stub axles (see FIG. 8) fixed in each corner of the outer side of the two

side plates

688 and 690. The rollers roll along the top and bottom surfaces of two horizontal steel bar tracks 718 and 720 (FIGS. 7 and 8) which are fastened to the rigid support framework of the front mill housing 66, preferably by machine screws.

Tracks

718 and 720 are parallel to the mill feed path axis and accurately guide the reciprocation of the rolling stand 62. The four upper rollers support the weight of the rolling stand and the four lower rollers prevent pitching of the stand during operation. Horizontal fore and

aft grooves

722 and 724 in the outer surfaces of

respective side plates

688 and 690 carry six anti-friction gibs 726, made from bearing bronze, which provide a close sliding fit against the opposing faces of the two

horizontal tracks

718 and 720 and prevent yaw, or cocking of the rolling stand sideways, during operation.

The rolling head assembly 680 includes a thick walled cylinder 730, which carries the rollers, a roller separator,

roller strap tracks or gibs and track adjustment mechanism, and is removably inserted into the carriage through its front wall opening 702. The cylindrical outer surface of the head 680 has a close fit through the front and rear walls of the carriage and is maintained against rotation relative to the carriage by a key 732 and cooperating key ways in the head and at the bottom of the rear wall 692. A peripheral outer flange 734 at the front end (right hand side of FIG. 6) of the head cylinder 730 abuts against the front carriage wall 694 to limit insertion of the head and axially locates the head in the carriage. An arcuate cross bar 736 placed in an arcuate groove 738 across the top of cylinder 730, and fastened by screws 740 to the rear of carriage front wall 694, rigidly locks the head to the carriage.

Fixed by screws at equi-angular locations on the inside surface of cylinder 730 are three slideways 742, seen in FIGS. 6 and 9, each of which has an inwardly facing, axially disposed channel track 744. A slide or carrier 746, made from a steel block, having a somewhat triangular cross-section, has three outwardly facing slide bosses 748. F astened by screws to each slide boss 748 is a channel shaped, bearing bronze, gib 750, which enable the slide to slidably fit the channel tracks 744 of the slideways 742, and maintain the slide 746 non-rotatable relative to the head yet permit an axially slidable relationship. An axial through bore 752 in slide 746 is dimensioned to provide passage with a free fit for a pipe blank. Extending back from the rear end of slide 746 at the sides ofthe bore are two integral, laterally spaced apart arms, 754 and 756, with aligned lateral cross bores in their ends. Connected to each of the

arms

754 and 756 by individual axle pins 758 is the forked

end

760, 762, of an individual slide operating connecting rod, 764 and 766, respectively. The other ends of the two

rods

764 and 766 are connected to the rocking lever assembly, as will be described, hereinafter.

Coextensive with the slide 746 and secured by nuts and studs 768 to its front end is the body 770 of a unit termed a separator, which keeps the working rollers in proper position in the head when they are not actually performing a rolling operation. The separator body 770, shown indetail in FIG. 10, is essentially triangularly shaped in cross section (see FIG. 8), has a large concentric, axially disposed through bore 772 and axially disposed stud bores 774, in each of the arms through which the fastening studs 768 project. Intermediate its two ends and between its three arms the body 770 has three recesses or windows 776 disposed 1 20" apart. The ends and sides of each window are accurately shaped to radially receive a working roller 778 and front and rear roller shank bearing inserts 780 and 782. The inserts are channelled to freely bridge the center'working groove portion 783 of rollers 778 with their flanges shaped with arcuate surfaces to rotatably fit the two shanks 784 of the associated roller.

Two hard steel cylindrical inserts 786 and 788 are inserted I in respective front and rear ends of the coaxial through bore 772 and then are welded to the separator body 770. The inner ends of body cylindrical inserts project slightly into the roller working space formed by the intersection of the three windows 776 and are cut away as at 790 and 792, under the ends of each window, as an extension of the bearing insert walls. The bottom of each

bearing insert

780 and 782 has a recessed

spring pocket

794 and 796, respectively, which seats a small, coiled compression spring, 798 and 800, respectively. Each working roller 778 with a set of two bearing

inserts

780 and 782 and their respective balancing springs 798 and 800 are radially inserted into each of the separator windows 776.

The inserts slidably fit the walls of their windows and in turn hold the working roller by their cylindrical shanks. The inserts with the rollers are prevented from moving radially out from within the window by a special locking plate 802 secured by a screw to the separator body 770. The two balancing

springs

798 and 800 seat on the cutout flats 790 and resiliently bias their inserts and retained roller 778 outwardly to the limit position dictated by the lock plate 802.

During the rolling operation the working rollers 778 are supported (by means of their shanks 784) and roll on the contour surfaces of the support planks or straps 810, as will be hereinafter described. The spring balancing of each working roller 778 considerably softens their working conditions during the moment of pipe blank feeding and rotating which occurs at the beginning of the rolling process. The spring balancing also provides gradual speed increase after reversal of the stand into its forward pass and prevents slippage of the roller shanks 784 along the support planks 810, as well as eliminating lashing of the pipe by the rollers during the clamping moment (grabbing).

Balancing of the working rollers is also necessary during the rolling of the forward end of the pipe onto the mandrel.

The two cylindrical front and

rear inserts

786 and 788 have inside diameters permitting free passage of a pipe blank. A threaded end 804 of the front insert 786 projects beyond the front face of the separator 770 and receives spacing washers and gaskets 806 secured by a nut 808. The studs 768 project through the washers and gaskets 806 and the nuts screwed on the studs transfer clamping force through the washers to the face of the separator body 770 to fasten it securely on the slide 746. Thus the separator with the working rollers will reciprocate as a unit with the slide.

The perspective view of FIG. 13 clearly illustrates how three working rollers and their track strap groupings are arranged. The straps 810 are hard steel channels, with

upper edges

812 and 814 of the flanges carefully contoured to provide inclined roller track formers. The bottom 816 of each strap as shown in FIG. 14, is flat but inclined up in a direction toward the front end of the strap. FIG. 14 is a distorted view showing the track edge contour 812 substantially exaggerated for illustration. The actual contour change is quite small. The groove working surface 783 of the roller rides with a sliding fit between the strap flanges while the large diameter stub shanks 784 take the rolling load, bearing on and rolling along the contoured

edges

812 and 814 of the strap flanges during the fore and aft passes of the roll stand. I I

Returning to FIGS. 6 and 9, the side faces 818, of fixed slideways 742 are spaced from and are parallel with adjacent slideway side faces 818 to constitute three guideways for the three roller track straps 810, each of which is disposed in a guideway between adjacent faces 818 of the slideway 742 fitting with a snug sliding fit against an abutment part 820 of a rear cover plate 822 fastened on the thick-walled cylinder body 730 by screws. An inner front housing cover plate 824 is held on the front of the cylindrical body 730 by screws and provides a front retaining abutment for axially holding the straps against the rear abutments with a snug but sliding fit.

Under each strap 810 is a flat wedge shaped adjusting gib 826 extending the length of the strap and having an inclined face which matches and engages the bottom inclined surface 816 of the associated strip 810. The front end of each wedge gib 826 is fastened to a common ring 828 which in turn is fastened by screws to a bushing ring 830 which has screw threads 832 on its outer periphery. A ring gear 834 with screw threads 836 on its inner periphery is threaded on the screw threads 832 of the bushing ring 830 and journalled adjacent the front end of cylindrical body 730 by two

ring bushings

838 and 840 held in place by a gear cover 842. At the top of the housing and meshed with the ring gear 834 is a small pinion gear 834 keyed on an operating shaft 846 joumalled in bushings mounted in the top walls of the gear cover 842. The pinion shaft 846 projects through to the front of gear cover 842 and secured thereto is a hand wheel 848. Rotation of wheel 848 will rotate the ring gear 834 and, via its threaded connection with ring bushing 830, will shift the wedge gibs forward or backward to adjust the strap tracks 810 radially inward or outward. The screw thread connection between ring gear 834 and ring bushing 830 constitutes an irreversible connection so that once a wedge adjustment is made by the hand wheel, it is self-maintaining, although a locking pin 849 can be provided to engage the pinion teeth. The purpose of adjusting the radial disposition of track straps 810 is described in a following section of this description.

Track straps 810 are held outwardly against the wedge gibs 826 by spring loaded studs 850 projecting through free fitting apertures in the cylinder body 730, slotted apertures 852 in the wedge gibs 826 and screwed into a threaded hole 854 (FIG. 13) in the bottom of a track strap 810. A cupped washer 856 and a coil spring 858 are held over the outer end of each stud by a nut with the washer and spring recessed into the wall of the cylinder body 730 and provide the bias force on the track straps 810.

ROCKING LEVER ASSEMBLY The rocking lever assembly 64 is actually two spaced apart heavy levers 870 and 872 (FIG. 7) assembled on a rock shaft 874 intermediate the lever ends. Each lever has a collar 876 welded to its side face at the rocking axis and with a spacer sleeve 878 between the collars are fixed on shaft 874 by suitable set screws. The ends of rocking shaft 874 project beyond the outer sides of each lever and are journalled in roller bearing sets 880 secured in pillow blocks 882 bolted to

heavy angle brackets

884 and 886 fixed to the rigid internal frame of the roller stand housing 66.

The lower ends of the spaced

levers

870 and 872 constitute a fork coupling into which fits the front end of the aforedescribed connecting rod 138 (FIG. 1b). A connecting pin 888, placed through apertures in the lower ends of the levers and the front end of connecting rod 138 couple the rod and lever. Lock plates 890, fastened by screws hold the pin 888 in position and a grease fitting 892 is included in the connecting pin 888. The lower ends of

levers

870 and 872 are reinforced by a brace rod 894 and spacer sleeve 896.

The spaced apart

upper arms

898 and 900 extend up on either side of the pipe blank feed path axis with their ends located above the top of the front mill housing 66. The upper lever ends are apertured and receive

collared bushings

902 and 904 which journal the

stub axles

906 and 908 of a trunnion 910. The rear threaded end 912 of the roll stand connecting rod 686 passes through the trunnion body and is clamped by two

lock nuts

914 and 916 enabling adjustments to the operating length of the rod 686.

A fork fitting 918 on the front end of roll stand connecting rod 686 connects to an adjustable axle 920 held in a shiftable dummy block 922 slidable up and down in a canted guideway 924 in the roller carriage yoke post 684. An upstanding stud 926 connects to and is pinned to the dummy block 922 and projects through a screw sleeve 928 threaded down through the top of yoke post 684 and abutting the dummy block 922. The upper end of stud 926 is threaded and receives a lock nut 930. A second lock nut 932 on the sleeve nut enables locking its adjustment. The dummy block 922 can be shifted by loosening the two lock nuts and adjusting the sleeve nut 928 for purposes to be hereinafter explained.

Between the rocking shaft 874 and the ends of both of the

upper lever arms

898 and 900, the arms are slotted at 934 and 936 and receive slide block bushings on the ends of axle pins 938 and 940 which project inwardly and journal the respective ends of the two separator

slide connecting rods

764 and 766, via suitable bushings. The facing ends of the two

axle pins

938 and 940 pass through apertures in the arms of an adjusting yoke 942 (which bridges the pipe blanks feeding into the rolling stand) and are secured to the arms by nuts 944. The threaded stem 946 of yoke 942 projects up through a hole 948 in a rigid cross brace 950 secured between the two upper lever arms. By manipulating the two

lock nuts

952 and 954 on the threaded yoke stem 946 the yoke 942 can be adjusted up or down in the

lever slots

934 and 936, in conjunction with adjustment of the roll stand dummy block 922, for purposes as will be explained.

Shown in FIG. 5, an indicator pointer 956 is secured on the end of yoke axle 940 to enable predetermined adjustments of the yoke 942. A similar adjustment indicator 958 is included on the outside of the rolling stand dummy block 922.

FIG. 1 1 is a representation of the manner in which three rollers 778 with stub axle shanks 784 are disposed to roll along three channel type track straps 810 in a heavy cylindrical head 730, with the roller peripheries rolling against the outer surface of a pipe blank 966 fitted over the mandrel head 252. FIG. 12 is a similar representation showing a five roller embodiment wherein the track formers are bars 970 contoured to fit the groove peripheries of the working rollers 972. in the five roller embodiment the rollers are too close together to enable use of the large diameter axle shanks. The five roller head 730' contains all components such as slideways, separator, and wedge gibs as have been described for the roller head 730, the components difiering somewhat in structural shape to accommodate the bar tracks 970 and rollers 972 without shanks.

Although the aforeidentified article from Metalurgizdat 1966 describes the precise technique of making the roller track contours, a diagrammatic strap track 810 is shown in FIG. 15. If the roll stand pass is 450 mm, the straps 810 are shifted 450 mm and the rollers roll that distance along the tracks and essentially half that distance along the pipe blank, thus the track contours must be long enough to accommodate the 450 mm roller travel and the mandrel head is disposed at least the length of the roller travel along the pipe blank.

The work surface of the support track 812 (FIG. 14) consists of the following segments: A-the roller opening at the pipe feeding and rotating position; B--reduction segment (compression); C--reduction segment; and Dcalibrating segment.

The purpose of each of these segments is analogous to the purpose of corresponding segments of a pass groove of cold rolling pipe mills of the roll type.

The decrease of the pipe blank diameter to a finished pipe diameter during the cold rolling on the thin-wall mills is quite small, due to the fact that the radius of the pass groove which is constant along the perimeter of the roller is equal to the radius of the finished pipe. In the case of considerable difference between the diameter of the blank and the finished pipes the rollers will cut into the blank. This leads to the intensive flow of metal into the spaces between the rollers and to the spoiling of the pipe surface. During the comparatively small reduction of the pipe during the rolling process the clearance between the inner surface of the blank and the mandrel usually does not exceed 1.0-1.5 mm. Therefore, the length of the reduction segment B can be selected within the 10-12 mm limit.

The contour of the track segment A, corresponding to the blank feeding and pipe rotation jaw opening, must guarantee impossibility of contact of the rollers with the pipe blank during the feeding and rotation operations.

ROLLING STAND OPERATION The cold rolling mill rolling stand 62 works on reciprocating motion principle. The rolling of the pipes is carried out on a stationary cylindrical mandrel head 252 with the help of three or more (depending on the adopted scheme) working rollers 778. At the end of a straight forward pass of the stand 62 the rollers 778 have been moved together to form a closed round groove in cross section, essentially as seen in FIG. 11.

The working rollers are supported by large diameter shanks 784 or, alternatively their work surface (groove surface), by means of contoured tracks such as 810 which provide the regulation of the ring space between the roller groove and mandrel 252 along the work pass of the stand. The ring groove formed by the three rollers at the beginning of the work pass of the stand is larger than it is at the end of the pass.

The roll stand 62 consists of the thick walled sleeve 730 inside which are installed three or more support tracks 810 along which the working rollers 778 roll. Synchronism of the longitudinal displacement of the rollers is provided by a separator 770 fastened to the slide block 746. The position of the slide block 746 in relation to the sleeve 730 is fixed by the yoke 942. The rolls with the separator, support tracks, and thick-walled sleeve are installed in the welded carriage 682 of the roll stand, and can be quickly and simply removed and replaced with minimum efiort. The roll stand is connected with the crank and reduction mechanism 82 by rocking lever assembly 64 which imparts the reciprocal motion to the stand.

During the movement of the rocking lever assembly which, as has been hereinbefore described, is connected to both the thick-walled roll stand head 730 and to the separator by a parallel connecting rod arrangement, the operating force is transmitted to the thick-walled head 730 by the heavy connecting-rod 686, the slide 746 being merely reciprocated in synchronization to maintain the rollers in proper axial disposition at the beginning of the pass. The length of the separator travel is the actual working pass of the rollers and is determined by the position of the connecting rods 764 in connections to the rocking lever in relation to the rocking axis of the rocking lever. This position can be changed by means of the adjustable yoke 942.

Taking into account the operation conditions, the slide connecting rods 764 must be parallel to the head connecting rod 686 during carriage reciprocation. If the lock position of the slide connecting rods 764 is changed, the parallelism is disturbed. The parallelism is re-established by regulation of the length or connection point of the head connecting rod 686. The two points of attachment of the separator slide connecting rod and that of the carriage to the rocking lever are situated in such a way that the linear speed of the roller separator and the magnitude of its displacement along the rolling axis is approximately twice as small as that of the carrlage.

In order to compensate for the elastic deformation of the working instruments (tools) and the cylindrical head, the possible inaccuracies in the manufacture of the instruments, and the adjustment of the mill, the special wedge gibs 826, provided with adjustment via the hand wheel 848, enable regulation of the strap track height.

During the development of the separator (retainer) and the strap tracks the possibility of insignificant displacement of the rolls along the working surfaces of the support tracks in the transverse direction was incorporated. This allows the self-adjustment of the rollers along the rolled pipe and decreases considerably the unevenness of the deformation along the perimeter of the pipe, thus improving its quality.

The spring balancing of the roll stand rollers considerably softens their operation conditions during the moment of feeding and rotation of the blank and at the beginning of the rolling. The balancing provides a gradual increase in roller rotation speed after the carriage has been reversed, precludes the slippage of the shanks along the support tracks, and at point of impact of the rollers on the pipe during the seizure moment.

The components of the mill are quite simple in form and are simple to manufacture. The work profile of the strap support tracks are a combination of sloping planes. The groove of the roll corresponds to the size of the finished pipe and is maintained along the entire perimeter of the roller. When switching from the rolling of pipes of one diameter to the rolling of pipes of another diameter the rollers and mandrel are changed and the lever system of the carriage is readjusted.

In the exemplary machine the following conditions exist keeping in mind that the main motor is a three speed electric motor.

1. Transmission ratio number from motor to the crank gear l 2. Transmission ratio from the motor to 7. Number of revolutions 715, 960, 1430 rpm 8. Number of double passes of the Rolling 140/95/70 pass/min.

Stand 9. Length of the Rolling Stand pass 450 mm.

ROLLING MILL OPERATION In the exemplary mill, loading of the pipe blanks is carried out manually. During the work process the mill can be operated by one operator and allows the rolling of measured blanks 4 meters in length as well as unmeasured ones less than 4 meters in length.

A rod 250 with a required diameter and length of mandrel head 252 is placed into the mill. The blank feeding chuck is placed into extreme rear position.

The feed chuck is opened and the coupling of the feeding and rotating mechanism is placed into working position. The mandrel rod clamp 84 is just closed manually on the mandrel rod end grooves to locate the mandrel and then the electromagnetic blank clamp 88 is closed on the front part of the mandrel through a terminal switch and electric solenoid 642. The mandrel clamp is then opened.

The pipe blank, coated internally with a lubricant emulsion, is pushed over the mandrel through the mandrel end clamp and into the sector between the mandrel end clamp and intermediate blank clamp, after which the mandrel rod end clamp is closed manually. When that is done, via its terminal switch 410, which is actuated by closing the mandrel rod end clamp, the electromagnetic intermediate blank clamp 88 opens automatically.

The pipe blank is next manually clamped in the lathe type feeding chuck head. When rolling pipes with a rigid chuck the angle regulating handle on the feeding and turning mechanism is placed into position corresponding to the blank rotation angle of 5810 andwhen rolling is done with floating chuck the handle is placed into position corresponding to the angle of rotation of 72. The necessary blank feeding value is chosen by shifting of the feeding speed shift handles.

Due to technological reasons, the start of rolling of the forward end of the first blank is carried out at a fast feed-in speed.

The feeding and turning operations are actually a combined operation performed when the working carriage is in its extreme rear position and the work rollers are set apart at a maximum distance from the axis of the tube rolled.

Viewing FIG. 15, upon start of the forward travel of the carriage and contoured track 810, a part of the tubular pipe blank stock 966 which has already been fed is gripped by the work rollers 778. Being brought together radially, the rollers float" in the'direction of the carriage movement, and periodically reducing this part of the stock, they roll it over a cylindrical mandrel 252 to the desired diameter and wall thickness. During the return stroke of the carriage, some reduction of the part of the tube still on the mandrel head also takes place owing to elastic compression of the working tool-working carriage system.

For purposes of visual demonstration, the kinematics of the process of tube rolling by rollers may be compared to rolling a pencil held down by a palm over a table, the palm moving in the longitudinal direction. In this case the palm will correspond to the thick-walled tube of the working carriage accommodating the shaped track straps; the pencil, to the work rollers; and the table surface, to a tube being rolled on a stationary mandrel.

The advantage of the process of tube rolling by rollers are as follows:

a. Small diameter of work rollers and corresponding reduc-. tion in the specific roll force and in the contact surface between the metal, the roller and the mandrel.

b. Some decrease in elastic compression of the rollers and the mandrel and the possibility for producing tubes with much thinner walls.

c. It is possible to roll tubes of much smaller diameters as compared to the Pilger roll-type mills.

d. The working tool may be manufactured with an accuracy of 10.01 mm.

e. There are no expensive roll bearings having low service life.

f. Sliding of the roller pass surfaces over the tube rolled is sharply reduced owing to a greater number of rollers and the constant crossdsection of their grooves.

g. Metal sticking to the working tool is minimized due to some reduction in the specific roll force and sliding.

h. Self-aligning of the rollers over the tube which minimizes the possibility of rolling marks formation on the tube.

i. It is possible to roll the so-called non-scratched" tubes, having outside and inside surfaces of high quality finish, which, apart from all other factors involved, is aided by the use of a cylindrical mandrel rotated synchronously with the tube being rolled.

As shown in FIG. 16, the peripheries of a roller for a three roller stand are beveled at their edges on angles of 120 so that the three rollers will meet and mate with a true ring cross section when they reach the finishing segment of the tracks. The bevel angle limits the permissible shank width and diameter. in rolling out of the rollers, the sharp bevel R is rolled ofi' until the angle of the tangent to the peripheral edge zone of the profile groove rolling zone of the roller is smaller than the normal 60 angle normally formed by a sharp bevel edge. The amount of necessary rolling out of such roller edges depends upon the amount of diametral reduction between the pipe blank and that of the finished pipe. The chart shown in FIG. 17 provides the correct rolling out angle for the diametral reduction.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent 1. A pipe mill reducing roll stand adapted to reciprocate along opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis, said roll stand comprising: a carriage with hearing means adapted to engage the tracks and reciprocally mount said stand on the tracks; a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis; a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head; working rollers in said separator spaced at equi-angular locations around said axis; means resiliently mounting each of said working rollers for limited radial shift in said separator comprising bearing inserts with surfaces embracing cylindrical surfaces on said working roller, first guide means in said separator, second guide means on said bearing inserts cooperating with said first guide means to confine said bearing inserts and associated roller as a unit and permit radial reciprocation of said unit between limit positions, coil springs disposed between said bearing inserts and said separator biasing said unit radially outward, and abutment means on said separator defining the limit positions of said unit; and means on said carriage enabling attachment of reciprocable drive means.

2. A pipe mill roll stand, as defined in claim 1, wherein said inserts have spring seat recesses facing the center of said separator, said springs are small compression coil springs seated in associated ones of said recesses, and said abutment means include abutment portions on the interior of said separator, spaced radially from its axis, to provide the other seating surfaces for said springs.

3. A pipe mill roll stand, as defined in claim 2, wherein said rollers have a groove working profile which is constant along the roller perimeter and cylindrical journals on each side of said working groove; each bearing insert in a block with two legs, contoured to bear on the two shanks, bridging the working profile; two of said blocks and an embraced roller slide radially in a window provided in said separator; and a removable lock plate on the outer side of said separator overlays the window and retains said inserts and associated roller within said separator.

4. A pipe mill roll stand, as defined in claim 1, wherein said carriage has a frame construction with two apertured end walls; said roll head is a thick-walled cylinder which is inserted through the apertures in both of said end walls; removable means, secured to at least one of said end walls, cooperate with said cylinder to rigidly maintain said cylinder in accurate angular and axial disposition in said carriage and permit rapid removal and replacement.

5. A pipe mill roll stand, as defined in claim 4, wherein said carriage frame has side members; and said means enabling attachment of the power means comprises a saddle rigidly fastened to said side members and said one wall, and an upstanding post rigidly secured to said saddle and said one wall; and means in said post enable an adjustable connection to an end of a connecting rod, permitting shifting of said connection toward and away from said saddle.

6. A pipe mill roll stand, as defined in claim 5, wherein said drive means has parallel linkage means, including said connecting rod and link means connected to said separator, whereby reciprocable shifting of said drive means provides synchronized shifting of the thick-walled cylindrical head and of the roll separator at different rates.

7. A pipe mill roll stand, as defined in claim 6, wherein said head includes contoured working roller track gibs secured in said head against axial and angular shift and along which said floating working rollers roll during reciprocation of said head.

8. A pipe mill roll stand, as defined in claim 7 wherein means resiliently secure and bias said track gibs to the inside of the wall of said head, wedge means are disposed between each track gib and the head cylinder wall so that fore and aft shifting of said wedge means can change the radial disposition of said track gibs relative to the axis of said head cylinder; adjustment means on the front end of said head are attached to said wedge means to enable simultaneous adjustment shifting of all said wedge means.

9. A pipe mill roll stand, as defined in claim 8, wherein said wedge adjustment means includes: an axially shiftable ring bushing in the front end of said head connected to each said wedge means, said bushing having screw threads on its outer periphery; a ring gear with internal screw threads engaged with the screw threads on said bushing and journalled in the front end of said head against axial shift; and a ring gear operator including a spur gear joumalled in said end of said head and meshed with said ring gear.

10. A pipe mill support means and reducing roll stand reciprocably carried on said support means which includes opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis; said roll stand comprising a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks, a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis, a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head, working rollers in said separator spaced at equi-angular locations around said axis, and means on said carriage enabling attachment of reciprocable connecting rod means; a vertical rocking lever disposed in said support means adjacent the rear end of said roll stand with its rocking axis below the feed path axis and an upper arm projecting to an end connec tor located above the feed path axis; connecting rod means connected between said upper lever arm and said roll stand.

11. A pipe mill support and roll stand, as defined in claim 10, wherein said carriage has a frame construction with two apertured end walls; said roller head is a thick-walled cylinder which is inserted through the apertures in both of said end walls; removable means, secured to at least one of said end walls, cooperate with said cylinder to rigidly maintain said cylinder in accurate angular and axial disposition in said carriage and permit rapid removal and replacement.

12. A pipe mill support and roll stand, as defined in claim 11, wherein said carriage frame has side members; and said means enabling attachment of the connecting rod means comprises: a saddle rigidly fastened to said side members and said one wall, and an upstanding post rigidly secured to said saddle and said one wall; and means in said post enable an adjustable connection to an end of a connecting rod, permitting shifting of said connection toward and away from said saddle.

13. A pipe mill support and roll stand, as defined in claim 12, wherein said connecting rod means has parallel linkage means, including said connecting rod and link means connected to said separator, whereby rocking of said lever provides synchronized shifting of the head and of the separator at different rates.

14. A pipe mill support means and roll stand as defined in claim 10, wherein said connecting rod means includes link means connected between said end connector and said carriage, and adjustable link means connected between said upper arm means and said separator.

15. A pipe mill support and roll stand as defined in claim 14, wherein said link means between said end connector and said carriage has an adjustment device at the connection to the upper lever arm and a second adjustment device at the connection to the carriage.

16. A pipe mill support means and roll stand as defined in claim 10, wherein said rocking lever means has upper and lower lever arms and its rocking axis is located intermediate the ends of said upper and lower lever arms and the end of said lower lever arm provides means for connection to a reciprocating power drive means.

17. A pipe mill support means and roll stand as defined in claim 16, wherein said lever means includes at least two laterally spaced apart elongate members extended upwardly in balanced disposition on each side of the feed path axis and the lower portions of said elongate members constitutes a forked lower lever arm and include said means providing for a connection to a reciprocating power drive means.

18. A pipe mill support and roll stand as defined in claim 10, wherein the top portion of said roll stand includes attachment means providing drive transfer connection between said carriage and at least a portion of said connecting rod means.

19. A pipe mill support and roll stand as defined in claim 18, wherein said carriage comprises frame structure and said attachment means is an upstanding connector link rigidly secured on top of said frame structure.

20. A pipe mill support means and reducing roll stand as defined in claim 10, wherein said roll stand includes means mounting each of said working rollers for limited radial shift in said separator comprising bearing inserts with surfaces embracing cylindrical surfaces on said associated working roller, first guide means in said separator, second guide means on said bearing inserts cooperating with said first guide means to confine said bearing inserts and associated roller as a unit and permit radial reciprocation of said unit between limit positions.

21. A pipe mill support means and reducing roll stand reciprocably carried on said support means which includes opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis; said roll stand comprising a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks, a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis, a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head, working rollers in said separator spaced at equi-angular locations around said axis, and means on said carriage enabling attachment of reciprocable connecting rod means; a vertical rocking lever means disposed in said support means adjacent the rear end of said roll stand with its rocking axis below the feed path axis and an upper lever arm means with connection means located between the feed path axis; and connecting rod means-connected between said upper lever arm connection means and said roll stand, including adjustable link means connected to said carriage.

22. A pipe mill support and roll stand as defined in claim 21, wherein said adjustable link means has a first adjustment device at the connection to the upper lever arm and a second adjustment device at the connection to the carriage.

23. A pipe mill support means and roll stand as defined in claim 21, wherein said connecting rod means includes a second adjustable link means connected between said upper lever arm means and said separator.

24. A pipe mill support and roll stand, as defined in claim 21, wherein said carriage has a frame construction with two apertured end walls; said thick-walled roller mounting head is inserted through the apertures in both of said end walls; means, secured to at least one of said end walls, cooperate with said roller mounting head to rigidly maintain said head in accurate angular and axial disposition in said carriage and permit rapid removal and replacement.

25. A pipe mill support and roll stand, as defined in claim 24, wherein said carriage frame has side members; and said means enabling attachment of the connecting rod means comprises: a saddle rigidly fastened to said carriage frame and an upstanding post rigidly secured to said saddle and a said end wall; and said adjustable link means includes connecting means in said post enabling an adjustable connection permitting shifting of said connection toward and away from said saddle.

26. A pipe mill support and roll stand, as defined in claim 21, wherein said connecting rod means has parallel linkage means, including said adjustable link means and link means connected to said separator, whereby rocking of said lever provides synchronized shifting of the head and of the separator at different rates.

27. A pipe mill support and roll stand as defined in claim 21, wherein the top portion of said roll stand includes attachment means providing drive'transfer connection between said carriage and said adjustable link means.

28. A pipe mill support and roll stand as defined in claim 27, wherein said carriage includes frame structure and said attachment means includes an upstanding connector link rigidly secured on top of said frame structure, said attachment means further including a pivot'connection portion adjustably shiftable toward and away from said carriage in said upstanding link.

29. A pipe mill reducing roll stand adapted to reciprocate along opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis, said roll stand comprising: a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks; a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis; a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to' said head; working rollers in said separator spaced at equi-angular locations around said axis; means mounting each of said working rollers for limited radial shift in said separator comprising bearing inserts with surfaces embracing cylindrical surfaces on said working roller, first guide means in said separator, second guide means on said bearing inserts cooperating with said first guide means to confine said bearing inserts and associated roller as a unit and permit radial reciprocation of said unit between limit positions; and means on the top portion of said roll stand carriage enabling attachment of drive means for reciprocation of said carriage.

30. A pipe mill reducing roll stand as defined in claim 29, wherein said means on the top portion of said carriage includes an upstanding connector link rigidly secured on top of said carriage and a pivot connection portion adjustably shiftable toward and away from said carriage in said upstanding link.

31. A pipe mill reducing roll stand, as defined in claim 29, wherein said carriage has a frame construction with two apertured end walls; said roller mounting head is a thick-walled cylinder which is inserted through the apertures in both of said end walls; removable means, secured to at least one of said end walls, cooperate with said cylinder to rigidly maintain said cylinder in accurate angular and axial disposition in said carriage and permit rapid removal and replacement.

32, A pipe mill roll stand, as defined in claim 31, wherein said carriage frame has side members; and said means enabling attachment of the power means comprises a saddle rigidly fastened to said side members and said one wall, and an upstanding post rigidly secured to said saddle and said one wall; and means in said post enable an adjustable connection to an end of a connecting rod, permitting shifting of said connection toward and away from said saddle 33 A pipe will reducing roll stand, as defined in claim 10, wherein said rocking lever means comprises two parallel laterally spaced apart lever members vertically disposed in balanced disposition on each side of said feed path axis and the upper lever arm connection to said connecting rod means disposed said connecting means in vertical planar alignment with and above the feed path axis to provide a lateral force balance drive connection to the roll stand.

34. A pipe mill reducing roll stand as defined in claim 20, wherein said separator includes a set of at least three contoured roller pressure tracks along each of which one of said rollers is rolled during a pipe reducing reciprocation of said roll stand and wherein each of said rollers has a constant profile pass groove throughout the 360 circumference of the roller, the cross section radius of said pass groove being substantially equal to the radius of the finished outside diameter surface of a pipe being reduced, and both circumferential edges of each roller pass groove being rolled out to provide a relief from the radius of the pass groove, the roll out angle resulting in a reducfion within the range of from 2 to 15 in the angle of intersection between a tangent to a constant radius pass groove at a circumferential edge and a line parallel to the roller axis at the circumferential edge.

35. A pipe mill reducing roll stand as defined in claim 34, wherein the roller pass groove bears against and rolls along the associated contoured roller pressure track.

36. A pipe mill reducing roll stand as defined in claim 34, wherein each roller has large diameter cylindrical stub shaft shanks approximating the diameter of the base of the roller roll pass groove and said roller shanks of each roller bear against and roll along spaced apart track flanges on an associated one of said set of contoured roller pressure tracks.

, v NI E STATES ,PIATENT OFFICE CERTIFICATE OF CORRECTION vi 3,673,840 Dated, Ju1 4, 1972 Patent No.

lnvntofls) A'. I"; Tselikov" et a1 Itis certified that-error app ea ra in the ahci re identified patent and that said Letters Patent are he ehy corrected asshown below:

' On Title page, in title, after "Pipe" insert --Mill-.

- in Inventors, "Vladimisovich" should be -Vladimirovich--. v

I in Assignee, change "Nau chno Issledovat k ---Nauchno-'I'ssledcvatelsky m I 7 Col. 1, line 50, delete "end. An improved, and more reliable, parallel roll stand".

, line 75, change "driven" to --drive--. I

Col. 6, line 51, change "jdke" to --yoke--.

Col. 13, line 3, change "crossdse'ction" to--cross-- section-.

Claim 21, line 16, change "between" t'o --above--.

Signed and sealed this 2nd day of January 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Pater FORM PO-1050 (10-69) USCOMWDC 376m, 1 U.S GOVERNMENT PRINTING OFFICE [9B9 0J65-Z

Claims

1. A pipe mill reducing roll stand adapted to reciprocate along opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis, said roll stand comprising: a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks; a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis; a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head; working rollers in said separator spaced at equi-angular locations around said axis; means resiliently mounting each of said working rollers for limited radial shift in said separator comprising bearing inserts with surfaces embracing cylindrical surfaces on said working roller, first guide means in said separator, second guide means on said bearing inserts cooperating with said first guide means to confine said bearing inserts and associated roller as a unit and permit radial reciprocation of said unit between limit positions, coil springs disposed between said bearing inserts and said separator biasing said unit radially outward, and abutment means on said separator defining the limit positions of said unit; and means on said carriage enabling attachment of reciprocable drive means.

9. A pipe mill roll stand, as defined in claim 8, wherein said wedge adjustment means includes: an axially shiftable ring bushing in the front end of said head connected to each said wedge means, said bushing having screw threads on its outer periphery; a ring gear with internal screw threads engaged with the screw threads on said bushing and journalled in the front end of said head against axial shift; and a ring gear operator including a spur gear journalled in said end of said head and meshed with said ring gear.

10. A pipe mill support means and reducing roll stand reciprocably carried on said support means which includes opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis; said roll stand comprising a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks, a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis, a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head, working rollers in said separator spaced at equi-angular locations around said axis, and means on said carriage enabling attachment of reciprocable connecting rod means; a vertical rocking lever disposed in said support means adjacent the rear end of said roll stand with its rocking axis below the feed path axis and an upper arm projecting to an end connector located above the feed path axis; connecting rod means connected between said upper lever arm and said roll stand.

21. A pipe mill support means and reducing roll stand reciprocably carried on said support means which includes opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis; said roll stand comprising a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks, a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis, a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head, working rollers in said separator spaced at equi-angular locations around said axis, and means on said carriage enabling attachment of reciprocable connecting rod means; a vertical rocking lever means disposed in said support means adjacent the rear end of said roll stand with its rocking axis below the feed path axis and an upper lever arm means with connection means located between the feed path axis; and connecting rod means connectEd between said upper lever arm connection means and said roll stand, including adjustable link means connected to said carriage.

27. A pipe mill support and roll stand as defined in claim 21, wherein the top portion of said roll stand includes attachment means providing drive transfer connection between said carriage and said adjustable link means.

28. A pipe mill support and roll stand as defined in claim 27, wherein said carriage includes frame structure and said attachment means includes an upstanding connector link rigidly secured on top of said frame structure, said attachment means further including a pivot connection portion adjustably shiftable toward and away from said carriage in said upstanding link.

29. A pipe mill reducing roll stand adapted to reciprocate along opposed, spaced apart tracks, disposed parallel to a pipe blank feed path axis, said roll stand comprising: a carriage with bearing means adapted to engage the tracks and reciprocally mount said stand on the tracks; a thick walled roller mounting head rigidly fastened in said carriage coaxial with the feed path axis; a roller separator slidably mounted within said head for reciprocation along said feed path axis relative to said head; working rollers in said separator spaced at equi-angular locations around said axis; means mounting each of said working rollers for limited radial shift in said separator comprising bearing inserts with surfaces embracing cylindrical surfaces on said working roller, first guide means in said separator, second guide means on said bearing inserts cooperating with said first guide means to confine said bearing inserts and associated roller as a unit and permit radial reciprocation of said unit between limit positions; and means on the top portion of said roll stand carriage enabling attachment of drive means for reciprocation of said carriage.

32. A pipe mill roll stand, as defined in claim 31, wherein said carriage frame has side members; and said means enabling attachment of the power means comprises a saddle rigidly fastened to said side members and said one wall, and an upstanding post rigidly secured to said saddle and said one wall; and means in said post enable an adjustable connection to an end of a connecting rod, permitting shifting of said connection toward and away from said saddle.

33. A pipe will reducing roll stand, as defined in claim 10, wherein said rocking lever means comprises two parallel laterally spaced apart lever members vertically disposed in balanced disposition on each side of said feed path axis and the upper lever arm connection to said connecting rod means disposed said connecting means in vertical planar alignment with and above the feed path axis to provide a lateral force balance drive connection to the roll stand.

34. A pipe mill reducing roll stand as defined in claim 20, wherein said separator includes a set of at least three contoured roller pressure tracks along each of which one of said rollers is rolled during a pipe reducing reciprocation of said roll stand and wherein each of said rollers has a constant profile pass groove throughout the 360* circumference of the roller, the cross section radius of said pass groove being substantially equal to the radius of the finished outside diameter surface of a pipe being reduced, and both circumferential edges of each roller pass groove being rolled out to provide a relief from the radius of the pass groove, the roll out angle resulting in a reduction within the range of from 2* to 15* in the angle of intersection between a tangent to a constant radius pass groove at a circumferential edge and a line parallel to the roller axis at the circumferential edge.