FR2527948A1 - SUPPORT DEVICE FOR THE TIP-HOLDER BAR OF A HOT AXIAL DRILLING MACHINE FOR BILLETTES, LINGOTS AND THE LIKE - Google Patents

Abstract

THIS DEVICE INCLUDES A PLURALITY OF BEARING STRUCTURES, SENSITIVELY IN THE SHAPE OF A CRADLE, DIPOSED IN ALIGNMENT ALONG THE DRILLING AXIS AND EACH OF WHICH CARRIES THREE ROLLERS 18, 19, 25 WHICH CAN APPROACH AND MOVE AWAY FROM THE AXIS OF THE DRILLING DRILLING BY ANGULAR MOVEMENTS OF THE SENSITIVELY SELF-CENTERING TYPE. EACH SET OF THREE ROLLERS THEREFORE FORM A RIGID STRAPPING FOR THE TIP BAR 2, SO AS TO STRIKE THIS BAR AND KEEP IT IN A CENTERED POSITION. AS THE PROGRESSION OF THE DRILLING 2A ON THE TIP BAR, THE ROLLERS 18, 19, 25 MOVE A GOOD DISTANCE FROM THE DRILLING AXIS TO FORM A GLASS SUPPORT FOR THE ROUGHING .

Description

The present invention relates to a device

  support for the tip bar of a per-

  hot axial drilling for billets, ingots and the like.

  This invention relates more particularly to a device

  tif intended to stiffen the point-holder bar and to support it in a position centered on the drilling axis of a rolling mill

pressure piercer.

  A pressure piercing rolling mill is a machine

  able to transform a square billet into a axially drilled round blank This machine comprises a rolling stand provided with two controlled cylinders, with round grooves, a drilling point mounted at one end of a

  corresponding bar, which extends along the axis of the lami-

  swimming and drilling, on the exit side of this cage, and a pusher intended to push a square billet between

  the rolling cylinders and against the drilling tip.

  To perform axial hot drilling of a bil-

  lette, ingot or bar or equivalent with a de-

  as little eccentricity as possible, it is necessary

  as the tip bar of the piercing rolling mill

  be securely held on the drilling axis, ma-

  niere to present a great rigidity This necessity is felt in particular at the beginning of the drilling and especially when the ratio between the length and the diameter of the

  hole to be executed is around 25 or more.

  Up to now, the tip bar is hold-

  bare and held on the drilling axis by a plurality of pairs of jaws, supported by a suitable base and

  arranged in two alignments parallel to the drilling axis

  ge and symmetrical with respect to this axis Each jaw is substantially constituted by a roller with a vertical axis mounted at the end of an arm, the other end of which is

  rotatably mounted on a vertical axis carried by a trolley.

  A hydraulic cylinder, or other similar actuation device, controls the angular movements of said arm

  around said vertical axis, to bring the roller into contact

  tact with the tip bar or move it away from this bar-

  re The aforementioned carriage can move on guides

  horizontals, perpendicular to the drilling axis and is posi-

  adjustable on these guides In this way, the vertical rollers of each pair of jaws can

  be positioned differently from the drilling axis

  ge, to adapt to tip holder bars with

  different transverse dimensions.

  Although widely used, this tech-

  support bar tip tip presents the incon-

  comes from not giving the bar sufficient rigidity

  so that you can always withstand the important demands

  tations (end load) which are exerted on it during

  the operation of the pressure piercing rolling mill In ef-

  fet, according to the above technique, the tip bar

  is supported and held along two diameter generators

  trally opposed by pairs of vertical rollers while it is completely free at the top and bottom. The known technique therefore gives the tip bar a

fixing substantially in pincers.

  In addition, as the drilling progresses, the situation

  The load on the tip bar is deteriorating more and more. Indeed, while, on the one hand, the number

  links that keep the tip bar lower

  naked, since the pairs of jaws open one after the other to give passage to the drilled blank, on the other

  part, there is added to the load at the end a load la-

  gradually growing, due to the weight of the pre-drilled blank itself The tip bar thus

  can be flexed, giving rise to a situation

  very dangerous strain-deformation since it can

  bring the degree of eccentricity of the hole produced to levels

unacceptable calves.

  Furthermore, the fact that in each jaw there

  there are inevitably games in the couplings

  be the carriage and its guides, in the joints of the

  roller arm on its respective carriage and on the

  positive hydraulic actuation, leads to inaccuracies

  studies of positioning of the jaw relative to the drilling axis and, consequently, to a more or less significant accentuation of the eccentricity of the punch-bar

te with respect to said axis.

  The problem on which the invention is based

  is to make a support device for a bar

  tip in position centered on the drilling and rolling axis of a pressure piercing rolling mill, which has

  structural and functional characteristics

  to provide the bar with appropriate and effective stiffening

  effective, as well as support in the exact alignment of the drilling axis, even during progressive advancement

  of the blank drilled on this bar.

  This problem is solved according to the invention by a stiffening device for a tip-holder bar and for supporting this bar in the position centered on the drilling axis of a pressure piercing rolling mill, characterized in that it comprises a plurality of supporting structures, substantially in the form of a cradle, arranged in alignment to define a horizontal axis (A) which coincides with said

  drilling axis, each of said load-bearing structures

  taking: three levers articulated on corresponding horizontal axes, parallel to said axis A and whose traces

  on a vertical plane perpendicular to this axis A, are

  posed at the vertices of an equilateral triangle whose center

  tre of gravity is the trace of axis A on said green plane

  tical; three identical rollers, each of which is mounted idly at the end of a corresponding lever, each at the same distance from the corresponding axis, the axes of rotation of said rollers being in a common vertical plane perpendicular to axis A and intersecting in this plane the geometric axes of the corresponding axes; motor members intended to angularly move said levers and their

  respective idler rollers around said axes for the reports

  near or away from said axis A.

  Other features and advantages of the invention

  tion will be better understood on reading the description

  which will follow from an exemplary embodiment and in r 4 fé-

  rant to the accompanying drawings in which, Figure 1 schematically shows a side view and in elevation a stiffening and support device according to the invention for the tip bar of a pressure piercing mill; Figure 2 shows schematically in a plan view the device of Figure 1;

  Figure 3 shows schematically and to scale

  enlarge a section taken along line 111-III of Figure 2; Figures 4 to 6 schematically show on an enlarged scale the same detail as in Figure 3, in

  different operating conditions.

  As can be seen with reference to FIG. 1, a device according to the invention has been designated as a whole by reference 1, intended for stiffening and

  support of a tip holder bar 2 used in a laminate

  black pressure piercer 3 which was indicated schematically-

  in 4 the rolling mill stand and in 5, 6 the rolling mill rolls.

  Said device comprises a plurality of structures

  load-bearing structures 7, cradle-shaped, identical and dis-

  laid in alignment along a horizontal axis A which

  coincides with the rolling and drilling axis of said laminate

black 3.

  In the example shown, the device 1 comprises

  takes six barrel structures of the type described, which are arranged in three successive groups, spaced from each other

  others of predetermined intervals.

  Since the cradle structures 7 are

  all identical, both in terms of structure

  ture only of the function, we will describe below opposite

  of Figures 3 to 6 only one of these structures.

  In each of the barrel structures 7, are

  mounted three axes 8, 9 and 10, horizontal and parallel to-

  said axis A In particular, the arrangement of these axes 8, 9 and 10 in space is such that the traces of their geometric axes on a vertical plane perpendicular to the axis A, for example on the plane of Figure 3 constitute the

  vertices of an equilateral triangle whose center of gravity

  tee coincides with the trace of axis A on the vertical plane considered On each of axes 8, 9 and 10, is articulated a

  corresponding lever of the first kind 11, 12 and 13 Le le-

  sink 11, which has substantially the shape of a square,

  has a fork-shaped end lla which supports

  te an axis 14 horizontal and parallel to axis 8 On this

  axis 14 is articulated the end 15 of the rod 16 of a

  hydraulic rinse 17 which is mounted oscillating in a way

  classic on the supporting structure 7.

  On the other end of the square lever 11 is mounted an idler roller 18 A second idler roller 19 is

  mounted by conventional means not shown in the former

  end 12 a of the lever 12 This lever is mechanically controlled

  ment to the lever 11, by means of a rod 20 whose opposite ends 21, 22 are rotatably mounted on

  axes 23, 24 horizontal, parallel to axis 8 and res-

  pectively carried by lever 11 and by lever 12.

  The lever 13 also carries an idler roller 25, at its end directed towards the inside of the barrel structure 7 It should be noted that the

  axes of rotation of the idler rollers 18, 19 and 25 are

  wind in the same vertical plane perpendicular to the axis A and that, in this plane, they intersect the geometric axes

  corresponding axes 8, 9 and 10 It is furthermore

  mark that the rollers 18, 19 and 25 are identical and arranged at equal distances from the geometric axes of

  axes 8, 9 and 10 around which they can move an-

  regularly to approach and move away from said axis,

  by a movement of the self-centering type, as it comes out

  became clearer from the rest of the description.

  A tie rod 26 has an end 27 mounted ro-

  tative on a horizontal axis 28, parallel to the axis A, and conventionally supported by the lever 12 At the level of

  its other end 29, said tie rod 26 is engaged in

  smooth through a cylindrical body 30 rotatably mounted in a cylindrical housing 31 which has a horizontal axis parallel to the axis A This housing 31 is formed near the end of the lever 13 which is opposite the roller An adjustable stop in position, for example a nut 32, is mounted on the end segment 29 of the tie rod 26 to prevent this tie rod from being released from the cylindrical body 30. A hydraulic cylinder 33 is mounted oscillating on the cradle structure 7 and has a rod 34 which is articulated on a horizontal axis 36 parallel to the axis A and carried by a pair of ears 35, 35 fixed on the lever 13.

  The lever 13 and its roller 25 can move

  angularly in the opposite direction to that of the-needle

  those of a watch (in Figures 3 to 6) while the

  levers 11 and 12 remain stationary On the contrary, these

  sinks 11 and 12, with their respective rollers 18, 19 may

  wind move angularly clockwise, while the lever 13 remains fixed or even undergoes angular movements in the opposite direction

that of the hands of a watch.

  The preferred arrangement for fixed axes 8, 9

  and 10, as well as the preferred arrangement for the-

  viers 11, 12 and 13 with respect to said axes is such that the idler rollers 18, 19 move towards the axis A along

  ascending trajectories and that the roller 25 approaches

  che of axis A following a descending trajectory.

  Referring to Figure 2, we can still re-

  mark that the cradle bearing structures which constitute

  kill the second and the third groups are connected and

  stiffened with respect to each other in a direction pa-

  parallel to axis A by tie rods and spacers

  pectively schematized in 37, 38 and 39, 40.

  In the available spaces of the corresponding arms 41, 42, known per se and used in a known manner

  to bring a tip bar 2 into the working position

  vail on the axis A or to move away from this position a point bar with a blank 2 fitted on this bar The arms 41, 42 are mounted on shafts 43, 44 horizontal, mounted on both sides of the device according to the invention , preferably in positions symmetrical with respect to the axis A The shafts 43, 44 are actuated by motorized members, not shown in that they

  are conventional, to determine the angular displacements

res of the arms 41, 42.

  At the free ends of these arms, 41, 42, are

  articulated corresponding heads 45, presenting essen-

  partly in the form of a cradle, known per se, while at their other end, these arms are suitably

  balanced by counterweights 46, 47.

  The operation of the device described below

is the next.

  In the initial operating state (Figure 3),

  the set of three rollers 18, 19, 25 of each of the

  your barrel structures 7 is kept in close contact

  with the tip bar 2, by actuating the

  hydraulic rins 17 correspondents Under these conditions,

  the rollers 18, 19 and 25 hold the punch bar

  te 2 firmly centered on the drilling axis A and, opposite

  screw of this bar, they substantially realize a strapping

  rigid, that is to say a connection, which, by stiffening effi-

  the bar, improves the resistance of the latter

re to charge at the end.

  in addition to reducing the degree of eccentricity of the axial hole of the blanks produced, the invention provides the advantage of making it possible to use bars of more

  great length to produce axial drilled blanks-

  -ment of greater length, which corresponds to the

  most current technical trend.

  When the end 2 a of the blank reaches a dull or set of 3 rollers 18, 19, 25, for example, that of the first barrel structure 7, an order is sent to the

  hydraulic cylinder 17 of this structure by means of

  tifs detectors which we have omitted to represent because they are conventional The actuation of this jack 17 determines an angular displacement (in the opposite direction to that of the needles of a watch, seen in FIG. 3> of the lever

  11 around the geometric axis of axis 8, with away

  consecutive of the corresponding roller 18 with respect to

the tip bar 2.

  Under the effect of the link established between the-

  11 and the lever 12 by the tie rod 20 and the connection established between the lever 12 and the lever 13 by the tie rod 26, the levers 12 and 13 undergo simultaneously with the lever 11 identical angular displacements in the opposite direction to that of clockwise around

  geometric axes of their respective axes of articulation

  tifs 9, 10 At the end of these angular displacements identi-

  ques, in the same direction and simultaneous, the rollers 18, 19 and 25 take a position shown in Figure 4, which is calculated, not only, to allow passage and

  the advance of the blank 2 has on the bar but still and on-

  everything, to constitute a support centered on the axis A (sup-

  bezel type) for roughing in motion.

  The weight of the blank, which is gradually increasing, is fully supported by the dull rollers 18, 19 and 25 and during the entire rolling and drilling phase,

  bar 2 only undergoes end load without

  simultaneously bir no lateral load like those which it undergoes in the known technique The bar is therefore not subjected to bending deformations, which contributes significantly to keeping it in alignment

on the drilling axis.

  All the operations described above are

  subsequently executed on the dull rollers which follow the first dull, as these dull rolls

  They are affected by the blank drilled during production.

  tion. At the end of drilling, the drilled blank obtained and the bar inserted in this blank must be removed from the set of barrel structures 7 and one must bring

  a new tip bar in the position thus li-

berée.

  To do this, we first activate simultaneous-

  ment (or not) the set of cylinders 33, in the ap-

  suitable for printing on the corresponding levers 13 a new

  calf angular movement counterclockwise around the geometric axes

  axes 10 In this way, all the rollers 25 (the

  upper) are brought to the inactive position shown

  felt in FIG. 5 As already described, during

  during the angular displacement of the levers 13, the levers

  11 and 12 and the corresponding rollers 18, 19 remain im-

  mobile The tie rods 29 do not constitute an obstacle to

  displacement of the levers 13 since they can slide li-

  in the cylindrical bodies 20 and that the latter can rotate freely in their housings 31 formed

in the levers 13.

  When all the rollers 25 have been brought with

  safety in position away from axis A, position re-

  * 30 presented in FIG. 5, in which the blank and its point bar are supported by the rollers 18, 19 while they are free upwards, the shaft 44 is put into action, causing an angular displacement of the

  corresponding rocker arms 42 and an evacuation movement

  tion of the blank 2 a and the tip bar 2 inserted

in this draft (Figure 6).

  Then, by actuating the hydraulic cylinders

  17, the rollers 18 and 19 are brought back to the initial position

  tial shown in Figure 3, to form the sup-

  wearing a new tip holder bar 2 This new bar is positioned by actuation of the other shaft 43

  and corresponding rocker arms 41 Under these conditions

  the tip bar 2 is already securely aligned

  rity on the drilling axis A. Then, by actuating the jacks 33, all the

  rollers brought back into contact with the new bar

  tip 2, thereby achieving the plurality of straps ri-

  gides that block the tip bar in the central position

  trée on the drilling axis, giving it the desired rigidity

  rée. Of course, various modifications can be made by those skilled in the art to the device which has just been described by way of non-limiting example.

  without departing from the scope of the invention.

Claims (3)

R E V E N D I C A T ION S   1 stiffening device for a bar   tip and support this bar in centered position   on the drilling axis of a pressure piercing rolling mill,   characterized in that it comprises a plurality of support structures (7) substantially in the form of a cradle, arranged in alignment, along a common horizontal axis (A) which coincides with the drilling axis of said rolling mill (3), each support structure (7) comprising: three levers (11, 12, 13) articulated on corresponding horizontal axes (8, 9, 10) parallel to said axis (A) and whose traces on a vertical plane perpendicular to said axis (A) are arranged at the vertices of an equilateral triangle whose center of   gravity is the trace of the axis (A) in said vertical plane   cal; three rollers (18, 19, 25) each of which is mounted idly at the end of a corresponding lever (11, 12, 13),   each at the same distance from the axis (8, 9, 10) corresponding   dant, the axes of rotation of said rollers (18, 19, 25) lying in a common vertical plane perpendicular   said axis (A) and intersecting in this plane the geometric axes   ques corresponding axes (8, 9, 10); modern organs   clamps (17, 20, 26, 33) intended to angularly move said levers (11, 12, 13) and their respective rollers   (18, 19, 25) around said axes (8, 9, 10) for the reports   approach or move them away from said axis (A) with a movement substantially of the self-centering type.   2 Device according to claim 1, character-   laughed in that said levers (11, 12, 13) are connected   kinematically through them with tie rods   corresponding (20, 26), one (11) of said levers being activated actuated by a drive member (17).   3 Device according to claim 2, character-   laughed in that one (13) of said levers can move   angularly around said axis (10), under the action of an or-   corresponding motor shaft (33) independently of the two au- 12) very levers <11, 12).