US2703999A - Pilgrim rolling mills - Google Patents

Description

March 15, 1955 I N. J. GILLE 2,703,999

PILGRIM ROLLING MILLS Filed Nov. 24, 1953 2 Sheets-Sheet l Fig.v l

March l5, 1955 Filed Nov. 24, 1953 N. J. GILLE PILGRIM ROLLING MILLS 2 Sheets-Sheet 2 Fig. 5

A lll W, iv ffl/HHS United States Patent C) PILGRIM ROLLING MILLS Nils Jacob Gille, Sandviken, Sweden, assignor to See Fabriks Aktiebolag, Sandviken, Sweden, a corporation of Sweden Application November 24, 1953, Serial No. 394,151

1 Claim. (Cl. 80-14) The present invention relates to improvements in pilgrim rolling mills of the type having a reciprocating roll carriage as used to reduce tubular stock in a cold state.

This application is a continuation in part of my prior led application Serial No. 761,496, filed July 17, 1947, and now abandoned.

The main object of the invention is to provide in a rolling mill of the type stated novel means whereby such a mill may be utilised to produce tubes or tube sections that are externally cylindrical and internally conical, that is the finished tubes or tube sections will have a lengthwise decreasing or increasing wall thickness or internal diameter. According to the invention this object is accomplished by supporting the mandrel for axial movement independently of the tube blank in which it is positioned and by operatively connecting the mandrel support with the blank feeding mechanism to axially move the former synchronously with the latter at a reduced rate relative to the feeding movement.

The invention will be more closely described with reference to the accompanying drawings which by way of example show one embodiment of the invention and a modification thereof.

Fig. 1 is a side elevational general view of a rolling mill for the manufacture of internally conical tubes according to the invention.

Fig. 2 is a left hand end view of Fig. 1 on an enlarged scale.

Fig. 3 is a longitudinal central section, partly in elevation, of the forward portion of the mill of Fig. 1 on an enlarged scale, showing the reciprocntory roll carriage together with its operating means and with its rolls engaging a tube blank supported by a mandrel and a feeding chuck.

Fig. 4 is a transverse section taken substantially on line 4-4 of Fig. 3 and seen in the direction of the arrows, the tube blank being omitted and the rolls being rotated from the position of Fig. 3 to define their smallest working bore.

Fig. 5 is a longitudinal section, partly in elevation, of the rear portion of the mill taken substantially on the lines 5-5 and 5-5' of Figs. 2 and 6 respectively and showing the blank feed mechanism and the mandrel moving mechanism.

Fig. 6 is a cross-sectional view taken along lines 6.-6 of Fig. 5.

Fig. 7 is a side elevational view of the rear portion of a rolling mill and illustrating an alternate form of mandrel moving mechanism.

Fig. 8 is an enlarged cross-sectional view illustrating a detail of the form shown in Fig. 2.

Fig. 9 is an end elevational view of the arrangement of Fig. 7, as viewed from the left. l

Fig. l0 shows, partly in elevation and partly in section, a portion of a tube produced by the mill of the invention.

As shown in Fig. 1, the rolling mill embodying the invention comprises the following main parts, a stand 20 for a reciprocatory roll carriage 21, a b lank chuck 22 slidably supported on a bed 23, a housing 24 for'the blank feed gearing, and a mandrel moving mechanism, generally designated by 25.

Referring to Figs. 3 and 4, the stand 20 supports a roll carriage 21 which is adapted to be moved to and fro therein on rollers 26. Reciprocating movement is imparted to the carriage 21 by a crank disk 27 driven from 2,703,999 Patented Mar. 15, 1955 a suitable power source (not shown) and connecting rods 28. In the carriage two horizontal roll journals 29 are mounted, one above the other, which are provided with detachable roll segments or dies 30 in which tapering (conical) and eccentric working grooves 31 are formed.

The ends of the two journals 29 extend on either side of the carriage and are provided with gears 32 meshing in pairs to secure coordination of the action of the journals 29 and associated dies 30. On the ends of the lower journal 29 there are also mounted gears 33 which mesh with horizontal gear racks 34 supported in the stand 20. By this means the journals 29 with their Working dies 30 are caused to rock in time with the reciprocation of the carriage 21 by the crank mechanism 27, 28.

In the grip of the working grooves there is shown (Fig. 3) a portion of a tubular work piece or tube blank 35 under reduction. Internally of the blank there is provided a mandrel 36 comprising a tapered head portion 36a extending through the working region of the rolls and a shaft portion 36h extending rearwardly from said head portion out of the rear end of the blank. The surface of the mandrel head 36a and those of the working grooves 31 cooperate in the usual manner to form between them an annular space which decreases in cross section as well as in radial thickness forwardly through the working range of the rolls so that the tube section actually worked upon is reduced or squeezed out by these surfaces to the form shown, i. e. conical externally as well' as internally and with a forwardly decreasing wall thickness.

At its rear end the tube blank 35 is clamped in the chuck 22 which, as lalready mentioned, is slidably supported ori the bed 23. For moving the chuck 22 along its guide ways in the bed 23 and in particular for imparting to it and the blank held therein an intermittent feeding movement towards the rolls 29, 30 under a reducing operation the chuck has attached to it a feed screw 37 which extends rearwardly therefrom, through the gear housing 24, and therebeyond (see Figs. 5 and 7). Within the housing 24 the feed screw carries a nut 38 which is held against axial movement so that rotation of said nut will cause axial displacement of the screw 37 and the means 22, 35 attached thereto. For its rotation the nut 38 is provided with an integral gear rim 39.

As is well known in the art, the feeding of the blank to the rolls in a pilgrim mill must be intermittent and timed with the rocking motion of the dies. More particularly, as applied to the present embodiment these requirements mean that the feeding shall take place when the roll carriage 21 moves close to its rear or left hand end position (Fig. 3), that is to say, when the blank 35 is released by the dies 30 because of the fact that relieving recesses 40 formed for that purpose at the wide ends of the working grooves 31 and in adjacent peripheral portions of the journals 29 are opposed to the blank. These conditions are satisfied by the feed drive mechanism presently to be described with reference to Figs. 5 and 6.

An inputshaft 41 driven by the crank disk shaft 42 through a bevel gearing 43, 44 at the same speed as the latter extends into the gear housing 24. Fast on its inner end the input shaft 41 carries a cam disk 45 which cooperates with a cam follower 46 supported at the lower end of a lever 47. At its upper end this lever is mounted for free rotation about an axis and supports coaxially with this axis one element of a one-way clutch. In the present instance this clutch is shown in the form of a friction roller clutch and said one or driving element of said clutch comprises a generally cylindrical member 48 fixed to said lever and extending laterally thereof 4into the bore of the other element or housing 49 of said clutch which housing is fixed to a shaft 50 rotatably supported in a bearing formed in one wall of the gear housing 24. Within the clutch housing 49 the member 48 has peripheral notches 51 adapted to receive a corresponding number of friction rollers 52 and provided with wedging surfaces to firmly press the rollers 52 into engagement with the inner wall of the housing when the lever 47 is swung clockwise as occasioned when the raised portion of the cam disk 45 cooperates with the cam follower 46. Each actuation of the lever 47 by the cam disk 45 will thus cause engagement of the one- way clutch 48, 49 `and rotation of the clutch housing 49 and shaft 50 through a fraction of one revolution n a clockwise direction as seen in Fig. 6. The clutch housing 49 has a gear 53 formed thereon which is in mesh with the gear 39 on the nut 38 that engages feed screw 37. Thus, rotation of the clutch housing will cause a corresponding counterclockwise rotation of the nut 38, with a consequential axial displacement of the feed screw 37. Assuming the feed screw to be of right-hand thread such displacement will constitute an intermittent feeding movement of the tube blank 35 in the direction towards the rolls. For returning the lever 47 when the raised portion of the cam disk 45 recedes from the cam follower 46 and for keeping the latter in permanent contact with said cam disk a tension spring 54 is provided, said spring having one end attached to the lever 47 and the other end anchored to a stationary part, such as the Wall of housing 24. When the lever 47 moves counterclockwise under the action of said spring the one- way clutch 48, 49 will immediately become disengaged and the clutch housing 49 and the parts operatively connected thereto will remain stationary. It will thus be seen that the means just described constitute a mechanism effective to convert the continuous rotation of the main drive shaft 42 into an intermittent incremental feeding movement of the tube blank 45, the relative angular positions of the cam disk 45 and the crank mechanism 27, 28 as best seen from Figs. 5 and 6 being such that feeding takes places as the latter passes through a region adjacent its left hand dead center where the blank is freed from the rolls. The length of each increment of feed which is determined by the gear ratio of the gears 39 and 53 and the pitch of the feed screw 37 may by way of example be of the order of magnitude of 4 mm.

At the discharge end of the mill the finished tube is received in suitable guide apertures to hold it straight and prevent whipping. One such aperture is indicated at 55. Further, in addition to the feeding mechanism described the gear housing 24 may contain the usual means for rapid return of the feed screw and for turning the blank together with the mandrel through a selected angle, say 90, between the strokes of the roll carriage. For the sake of simplicity these means have been excluded from the present specification and drawings since they have no direct relation to the invention and may be of conventional form.

The structure so far described comprises the principal elements of a conventional pilgrim rolling mill of the type referred to which in operation will produce from a tubular stock a reduced finished tube which is cylindrical both externally and internally. Such operation is well known in the art and it is believed therefore that the indications already given will sui-lice for a complete understanding without going further into detail.

To obtain the object of the present invention, a pilgrim rolling mill of the type stated capable of producing internally conical tubes or tube sections, the following mandrel actuating mechanism is provided according to one embodiment of the invention shown in the drawings (Figs. 2 and 5). The mandrel shaft 36b extends rearwardly of the chuck 22, passes through the gear housing 24 and the rear end thereof is axially held in a tail stock 56 which is mounted for axial movement in guide ways 57 formed on a bed 58 disposed behind the housing 24. Under the tail stock 56 there is disposed a spindle 59 which is threaded at one end and which threaded end is received in a correspondingly internally threaded aperture formed in a projection 63 extending upwardly from the bed 58. At its other end, the spindle S9 supports a gear 60 which in turn is rotatably supported but held against axial movement by a bearing bracket 61 projecting upwardly from the bed. The gear 60 is connected to the spindle 59 by means of an elongated key 62 xed to the latter which permits axial movement of the spindle 59 relative to gear 60. Intermediate its ends the spindle 59 carries two spaced, iixed collars 64 receiving therebetween a depending forked lug 65 formed on the tail stock 56 and straddling the spindle. It will be seen that with the described arrangement rotation of the gear 60 and spindle 59 will cause axial movement of the latter and, hence, because of the axial connection provided by collars 64, and lug 65 similar movement is imparted to the tail stock 56 and mandrel 36. The operating power for the gear 60 is derived from the shaft 50 of the blank feed mechanism through a chain gearing comprising chain wheel 66 fixed to the shaft 50, chain wheel 68 fixed to tra one end of a longitudinal shaft 69 and chain 67, a second chain gearing comprising chain wheel 70 fixed to said longitudinal shaft adjacent its other or rear end, chain wheel 72 and chain 71, a gear 73 connected and coaxial with the last-mentioned chain wheel, and a gear 74 meshing with gear 73 as well as gear 60. The gear 74 is rotatably mounted on a stud shaft 75 and the gear 73 together with the associated chain Wheel 72 is similarly mounted on a second stud shaft 76 and these two stud shafts are carried by supporting member 77 rockably supported on the rear end of the longitudinal shaft 69. By this arrangement it is possible when desired to discontinue the drive to the gear 60 and mandrel tail stock 56 by moving the supporting member 77 counterclockwise so that the gear 74 becomes disengaged from the gear 60. For selectively holding the supporting member 77 in the engaged position as shown as well as in its disengaged position the member or arm 77 is provided with an arched lateral extension 78 which is slidably received in a sleeve member 79 formed on a bracket 90 projecting from the rear end of the bed 58. The arched extension 78 has two holes 80 each corresponding to one position of the member 77 and by aligning one of said holes with opposed holes formed in the sleeve 79 and passing a locking pin 81 therethrough the member 77 may be locked in the desired position. In the present embodiment the longitudinal shaft 69 is divided and its two parts connected by means of a differential gearing 82 (Fig. 8) to make possible to move the mandrel 36 in one direction or the other, as desired. When the housing 83 of said gearing is kept stationary as indicated by the pin 84 received in recesses formed in a stationary part and in the housing 83 the gear on the input shaft 69a rotates the gear on output shaft 69b in the opposite direction through the idle gears. On the other hand, when the housing 83 is free and input shaft 69a is connected to the housing as also indicated the gearing 82 functions as a direct coupling.

The modification shown in Figs. 7 and 9 diiers from the embodiment described above only in the means for reversing the drive to the mandrel and similar parts in the two cases have therefore the same reference numerals. In the modification the rockable gear supporting member 77 has two arms, one which carries the gears 73 and 74 and another which carries an idle gear 85 meshing with the gear 73 and a further gear 86 engageable with the gear 60. It is easily seen that rocking of the supporting member 77 so as to engage the gear 74 instead of the gear 86 with the gear 60 will cause reverse rotation of the latter. To keep the supporting member 77 in one or the other of its engaged positions or in an intermediate disengaged position the arched extension 78 has three holes for receiving the locking pin 81.

It will be seen that the described mandrel moving mechanism provides means for intermittently moving the mandrel 36 in either direction in time with the feeding of the blank 35 but in increments that are smaller than the increments of feed. To obtain the object of the invention said mechanism should produce a considerable speed reduction the greater part of which is taken care of by the spindle 62 whose threaded portion has a much smaller pitch than the feed screw 37. The magnitude of the required speed reduction depends on the length and degree of taper of the tube being produced and it may be varied within workable limits by using exchangeable chain wheels and gears with different gear ratios.

While one embodiment of the invention and a modication thereof have been described in detail it is to be understood that various modifications and changes may be made within the spirit of the invention as set forth in the appended claim.

What I claim is:

A rolling mill including a reciprocable roll carriage, cyclically operable means for reciprocating the carriage, reducing rolls supported in said carriage and adapted to periodically engage and disengage a tubular workpiece, a tapered mandrel for supporting the inner surface of the workpiece between said rolls, means for feeding the workpiece in increments to the rolls while the workpiece is free of the rolls including a shaft, means for intermittently driving the shaft when the workpiece is free of the rolls, and means operatively coupled to said shaft for moving the workpiece axially to effect feeding in response to the drive from said shaft, mandrel supporting means comprising an axially movable supporting rod extending rearwardly of the mandrel and including a rear end, a slidably mounted tail stock receiving the rear end of the rod, and means operatively coupling the feeding means with said rod to intermittently move the rod and thus the mandrel axially responsive to, in time with, and at a reduced rate of movement relative to the axial movement of feeding, said last mentioned means including a second shaft operatively coupled to said intermittently driven shaft, a fixed nut, a threaded spindle engaged in and axially movable relative to the nut, means connecting the spindle to the tail stock to move the same axially responsive to axial 10 movement of the spindle, and means operatively coupling said second shaft with said spindle for rotating the same, whereby rotation of said second shaft during the intermittent driving of the first shaft simultaneously imparts inter mittent drive to said spindle to move the same, and thus the workpiece and mandrel are simultaneously moved axially.

References Cited in the tile of this patent UNITED STATES PATENTS 1,952,841 Coe Mar. 27, 1934 2,192,808 Van Den Bunglaar May 5, 1940 FOREIGN PATENTS 3,371 Great Britain Feb. 24, 1891 367,966 France Y Nov. 16, 1906

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