FR2471244A1 - METHOD AND DEVICE FOR CUTTING TUBULAR PIECES - Google Patents

Abstract

TWO TOOLS 17 WHOSE SHARP EDGES ARE CONTAINED IN A SAME DIAMETRAL PLANE OF PIPE 3 AND PRESENT, IN THIS PLANE, THE DESIRED PROFILE FOR THE CUT END, ARE ACTUATED IN SYNCHRONISM BY AN ARTICULATED SYSTEM CONSISTING OF LEVERS 20 AND 21 HAS TWO ARMS AND OF 24-ECCENTRIC CONNECTING ROD SYSTEMS 25 DRIVEN BY A SAME SHAFT 26 IN TWO DIRECTIONS OF ROTATION AND AT TWO SPEEDS. APPLICATION TO CUTTING-PROFILING OF CAST IRON PIPES.

Description

The present invention relates to the cutting of tubular pieces into

rigid materials such as

  metals, plastics, asbestos cement, and

  particularly, but not exclusively, in cutting cast iron pipes. Cutting machines are known using

  less a record-wheel. These machines have the disadvantage

  deny being noisy and polluting. Moreover, they do not make it possible to obtain a given profile, chamfer and / or

  IO rounded, on the edge of the cut-off pipes.

  Cutting machines are also known from at least one shearing blade. These machines that

  work by shear are not suitable for

  smelting of cast iron pipes if a clean cut is required.

  I5 They do not allow either to obtain a profile to

  chamfered and / or rounded on the cut slice.

  The Applicant has therefore posed the problem of making a method and a device for cutting tubular parts, especially cast iron, which are fast, relatively quiet, non-polluting, which are able to make a clean cut without causing deformation, breaking or chipping of the tubular parts and which make it possible to obtain directly a rounded and / or a

end chamfer.

  For this purpose, the subject of the invention is a method for cutting a tubular part driven in rotation.

  around its axis and held fixed in translation,

  achieved by simultaneously attacking the section at.

  cut by means of several symmetrical cutting tools

  distributed around this section and each having a cutting edge which is contained in an axial plane of

  the tubular piece and whose profile corresponds to the

  guration desired for the cut end of this piece. In a particularly advantageous embodiment of this method, the tools of the axis are approached at a fast speed up to. their contact with the workpiece then at a slow speed during the penetration of the cutting edges into the wall of this workpiece, and when the cutting is finished, the tools are brought back to. starting position at a fast speed. During the cutting, the angle of attack of the tools is varied and the slow speed is gradually reduced, which improves

  IO surprisingly holding the tools and the quality of the cut.

  The invention also relates to a device for implementing this method. This device, intended to be used with a machine comprising means for clamping and driving in rotation of a tubular cutoff end I5 and means for axially holding the workpiece, is characterized in that it comprises a plurality of cutting tools. symmetrically distributed around the axis of rotation and each having a sharp edge that is

  contained in a plan passing through that axis and the pro-

  wire corresponds to the desired configuration for the cut end of the workpiece, and a single motor shaft to two

  direction of rotation connected to each tool by a

  abutment turning the circular motion into a movement

alternative almost rectilinear.

  In a preferred embodiment, each tool is mounted at the end of an arm of a two-armed oscillating lever, the other arm of this lever being connected to a connecting rod-crank system driven by the motor shaft. Such an articulated system makes it possible very simply to obtain both a modulation of the speed of movement of the

  cutting tools from a constant speed of training

  rotation of the tree, especially during cutting, and a

  slight variation in the angle of cut during penetration

  each tool in the wall of the workpiece.

cutting.

  In addition, each cutting tool preferably includes

  a cutting edge profile corresponding to. the one to be obtained on the cut end edge, which

  allows a single machining and a single pass of section-

  and shape the end of a tubular piece. In

  In particular, the sharp edge of each tool can

  carry a portion of bloodletting connected to a part of

braking by a rounded part.

  Thus, the device of the invention, while being

  1O of a simple design, allows cutting and profiling

  the pipes in the best times, in a relatively

  quietly and by eliminating the phenomena of

  the usual cuts, while ensuring an excellent

  slow appearance of the cut-off piece and a long life of

I5 life tools.

  Other features and advantages appear

  will be in the following description.

  -On the attached drawings, given only for

for example-:

  FIG. 1 is a schematic elevational view of

  side of a cutting machine provided with a device

  the invention; FIG. 2 is an end view of this machine taken looking at line 2-2 of FIG. 1; FIG. 3 is a schematic side view, partly in section, of a portion of the machine of FIG. 1, on a larger scale, illustrating the means for rotating and cutting a tubular piece;

  FIG. 4 is a partial schematic view of

  corresponding to FIG. 2, on a larger scale than this, illustrating the cutting device;

  FIG. 5 is a schematic diagram of the operation of the

  operating mechanism of the cutting device; FIG. 6 illustrates the variation curves of

  strokes and speeds of the cutting tools according to the

  rotation angle traversed by the rotary drive shaft;

  FIG. 7 represents a detail of the mechanism of

  operation of the contrac- tor; FIG. 8 is a partial plan view of a cutting tool and the wall of the tubular part, illustrating different positions of the profiled cutting edge of the tool and the sectioning profile obtained on the tubular part.

  Following the example of execution shown in

  The invention relates to a device I-cutting IO and profiling or finite-ion (making a chamfer and a rounded) of the plain end end 2 of a

  cast-iron pipe 3, interlocking 4. It would also apply

  the cutting of tubes made of any material: steel, aluminum, plastic, asbestos-cement, etc.

  Whatever the diameter of these tubes.

  The device 1 is part of a cutting machine which comprises at least one support post 5 and a hollow embroidery body 6 crossed by the pipe 3 along an axis X-X of horizontal rotation which is coincidental.

with the axis of the pipe 3.

  - Means of support and training in rotation of the pipe3.

  On the support pole 5 are mounted two idle rollers 7 opposite, symmetrical with respect to the axis X-X and axes parallel to this axis X-X. The rollers 7 are intended to-support the barrel of the pipe 3 in the vicinity of the socket 4. It is also provided means, known per se and not shown, for feeding a pipe 3 on the rollers 7 and introduction this pipe through the body 6 of the spindle to a position suitable for being cut,

  and also to evacuate the pipe after bucking and

its end 2.

  The hollow spindle 8 itself is mounted inside the body 6 via bearings 9 (Fig. 3). Pin 8, of axis X-X, carries at one end a coaxial tooth gear 10 for the purpose of driving

247124 4

  rotation of the spindle. by the output gear 11 of a motor

  12, and internally it carries means of

the pipe 3.

  These clamping means essentially comprise a reaction ring 13 axially fixed and secured in

  rotation of the spindle 8, a compression ring 14 movable

  axially under the effect of an annular hydraulic cylinder

  re 15 single-acting, and an annular jaw elastomer 16 disposed between the rings 13 and 14. When the cylinder 15 IO is fed, the jaw 16, compressed axially, inflates radially towards the axis XX and makes the pipe 3 integral pin 8. When the cylinder 15 is discharged, the jaw 16 resiliently returns to its rest configuration,

  in which its inside diameter is greater than the diameter

I5 outside meter of pipe 3.

  This clamping and training device

  pipe 3 is interchangeable depending on the

  different diameters of pipes to be driven and cut-off.

  To cut a pipe of a different diameter but still located within the dimensional limits of pin 8, simply change the rings 13 and 14 and

the elastic jaw 16.

- Cutting device 1.

  The cutting device 1 is carried by the spindle body 6. It comprises a pair of cutting tools 17 and

  two articulated drive mechanisms 18.

  a) Cutting tools 17 (Figs 1 to 4 and 8): There are, in this example, two,

  diametrically opposite to. the X-X axis and sym-

  placed in a direction of approach and recoil located in the horizontal plane P containing the axis of rotation X-X and normal to it. Each tool 17 forms a block having a flat cutting edge 19 (FIG 8) with ABCD profile, the oblique AB portion forming a chamfer, the curved portion, B, forming rounded and the straight portion CD, parallel to the axis XX, bleeding, that is, to. dig a gorge up. that the tubular wall is crossed

from one side to the other and cut off.

  The cutting edges 19 of the two tools 17 are contained in the same diametral plane passing through the axis

  X-X and exactly opposite each other, that is,

  re that every point A, B, C or D of a tool 17 finds

  his counterpart the other tool 17 on a line per-

  IO pendicular to the X-X axis. In this example, this diametral plane is the horizontal plane P. The active side of one of the tools 17 (on the left in Figs 2 and 4) is cleared

  upward, that of the other tool 17 down.

  b) Mechanism for actuating tools 17 (Figs 1 to 4 and 7): Each tool 17 is attached to the upper end of a tool arm on one side of the axis X-X and 21 on the other side of that axis. The arms 20 and 21 are

  contained in two perpendicular vertical planes

  X-X axis (Fig. 1 and 3). In end view (Fig.2 and 4), these arms are vertical or approximately; they are each articulated on an axis 22 carried by the spindle body 6, at an intermediate point of their length,

  and, to. their lower end, each of them is

  on one end 23 of a connecting rod 24. Each biel-

  is articulated, at its other end, on an excen-

  25. There are thus two eccentrics 25, likewise

  eccentricity R, keyed on a single tree 26 of

  rotational drag whose Y-Y axis is parallel to the X-X axis. The shaft 26 is carried by the spindle body 6, which it passes through, and is rotated on a

  fraction of a turn only (Fig. 5) by a motor group

  reducer 27 provided with means for reversing the direction of rota-

  shifting and shifting (not shown). More specifically, the geared motor unit 27 has two constant speeds, one fast V1 and the other slow

  V2, and ways to move from one. at. the other.

  The two eccentrics 25 are circular and arranged symmetrically with respect to. Y-Y axis and have respectively E and F points located on a cross section of the shaft 26 at a distance R

  center O of this section. The R value of their eccentric

  quoted is less (or possibly at most equal) to the radius of the shaft 26. The points E and F are respectively associated atx arms 20 and 21 and are diametrically opposed IO on a theoretical "eccentricity circle" G, center O and

  of radius R, shown in phantom in FIG. 7.

  The joints of the ends of the connecting rods 24 are made with interposition of needle crowns a

or beads 24a.

  I5 The articulated system 24--25 is from the point of view

  kinematics the perfect equivalent of a connecting rod system.

  crank arm crank OE or OF shown with strong exaggeration of the radius R in Figs. 4 and 5, while

  eccentrics have a very low eccentricity

  corn. c) Adjusting the position of the tools B 17 (Figs. 2 and 3) Each tool 17 has a lateral positioning pin 28 which, in the working position of the tool, is parallel to the axis X-X. The tool 17 takes place in a groove 29 of the tool arm 20 or 21 which is oriented parallel to the working plane of each tool 17, thus horizontally and orthogonally to the X-X axis of rotation.

  3. The groove 29 is provided with regular notches 30

  spaced apart and dimensioned to receive the lug 28 of the tool 17. Thus, it is, according to the selected notch 30, more or less close to the axis of rotation X-X. The notch 30 is chosen as a function of the diameter of the tubular part to be cut. In the position thus determined

  by the. notch 30, the tool 17 is tightened in the groove

  re 29 by a conventional device 31 wedge or clame and screw. d) Device for positioning the pipe 3 to the length

of desired cut: -

  Of known type, this device, not shown in

  purpose of simplification and clarity of the presentation,

  a photocell for locating the position of the end wafer of the cut-off part 3, a programmable electronic counter or preselection of the desired cutting length, a connection between the photocell and the counter and a connection between the meter and a drive device in translation IO diabolos of the pipe 3 parallel to its axis of rotation XX. When the end edge of the part 3 has reached the position corresponding to the desired cutting length,

  the meter stops the training device in transla-

  tion. The pipe 3 is then immobilized and tightened in the

  I5 pin 8 by means of the clamping device 13 to 16.

OPERATION:

  Or to cut the end of a pipe 3. This pipe 3 is put in place on the machine at

  through pin 8 as indicated above, its

  The tools 17 are located in their position farthest from axis XX, which corresponds to the position E1, F1 of the points E and F in FIGS. 5 and 6, the point E1 being slightly to the right of the high point of the circle G. l1) Driving in rotation of the pipe and fast approach of the cutting tools 17: The geared motor unit 12 is turned on, and the pipe 3 starts to turn about the axis XX, driven by the pin 8 and the jaw 16, in the direction f of Figs. 2 and 4. The geared motor unit 27 is started at the speed V in the direction corresponding to the rotation of

  the shaft 26 in the direction of FIGS. 2, 4, 5 and 7.

  The rotation of the shaft 26 in the direction g is effected

  It kills only a fraction of a turn and causes the eccentric arcs E1 E2 F1 F2 to traverse eccentric arcs E1 E2 F1 F2 on the eccentricity circle G of radius R (Figs 4 and 5). The heads of the rods 24 oscillate around their centers EF, which move; this results in a sinusoidal movement of the joints 23 of the connecting rods 24 along an arc of a circle centered on the axes 22, which is transmitted with reduction to the tools 17. Due to its large radius, the circular movement of the joints 23 is almost rectilinear, and the same is true of the one

tools 17.

) Slow cut

  The geared motor unit is controlled by a

  positive counting of the arcuate trajectory on the circle G of the centers E and F of the eccentric 25 and the heads of the rods 24. This counting device triggers the passage from the fast speed Vi (approach of the tools 17) to the slow speed V2 ( cutting) and vice versa (recoil

  fast tools 17 after cutting), as well as stopping

  of the geared motor unit 27 and the reversal of the rotation direction

  tion. When the centers E and F have reached the positions E2 and F2 corresponding to the arrival of the tools 17 in contact with the pipe 3, the counting device controls the passage

  of the geared motor unit 27 in low speed V2 without invert-

direction of rotation. -

  As a result, tools 17 go ahead

  slow or advance of work and remain there during the

  E2 E3 F2 F3 of the centers E and F of the connecting rod heads

(Fig. 5).

  The tools 17 (Fig. 8) start with a CD-length groove in the wall of the pipe, and then, as the wall is bled, the CBA profile with B-rounding also penetrates into the current wall. cutting, so that when the cutting edge 19 has passed through. apart from the wall. to achieve. the

  final position represented in solid lines after being

  Due to the intermediate positions shown in broken lines, the cut end of the pipe 3 matches the CBA profile of the cutting edge 19. Consequently, the pipe is simultaneously cut and profiled at its end.

  next, in this example, a-rounded and a chamfer.

  4) Quick return of the tools 17: 10 When each tool 17 has traveled a predetermined distance greater than the wall thickness of the pipe 3, and therefore after the fall of the cut-off piece 3 of the pipe, the counting device , reset to zero, stops the geared motor unit 27, reverses the direction of rotation, and I5 "again triggers the gear change from V2 to V1

  (fast speed). The. points E and F respectively travel

  trajectories E3E1 and F3F1 (Fig. 5). The ends 23, and therefore also the tools 17 as shown in FIG. 4, go backward

fast speed.

  The counting device stops the motor unit

  reducer 27 when each tool 17 is returned to. its posi-

  departure, that is, away from the wall. pipe a preset distance. ' This immobilizes the tree

26 and the tools 17.

   ) Loosening and evacuation of the cut 3 pipe: After cutting, the cylinder 15 of the spindle 8 is discharged, which causes the jaw to be loosened.

  16, which expands axially. The pipe 3 cut to length

  The desired width is then removed axially from the. pin 8 and evacuated by the known means not shown evoked

upper.

  6). Variation of the angle of cut during the advance

  Tools 17 (Figs 4- and 7): The arms 20 and 21 being articulated about the axes 22, as each tool 17 penetrates, they tilt by an angle x (Fig. The tools 17, linked to these arms, tilt at the same angle x. The initial angle of cut, at the start of the working advance ", has therefore decreased by x at the end of cutting. This angle decrease during the penetration of each tool 17 was found

  favorable for a better holding tools 17et for the.

  quality of the cut .; 7) Motion Cinematics Analysis: Reference is made to FIGS. 5 and 6. FIG. 5 IO illustrates the trajectories of points E and F and feet

  connecting rod 23, and FIG. 6 represents in the form of graphs

  both the trajectory e and the speed v of the connecting rods 23 as a function of the angle of rotation <traveled, for example by the point F. This trajectory I5 and this speed have a sinusoidal shape obtained from the two values constant V1 and V2 speed

  of rotation of the drive shaft 26. Due to the trans-

  mission of the movement by the levers 20 and 21, it can be considered that the curves of FIG. 6 represent the speed of movement (space and speed) of tools

17. -

  Reinforced lines have been shown in

  useful parts of the curve of trajectories and courses

  besides speeds corresponding to the speeds V1 and V2 of rotation of the drive shaft 26, in this area, the curve corresponding to V1 is situated above the curve

corresponding to V2.

  We see in this diagram of FIG. 6 that, on the F1 F2 course, the fast approach speed, which is modulated by the kinematic 24excentric connecting rod 25, decreases

  slightly after going through a maximum. At the end of

  near fast, when the counting device triggers the change of speed to pass the shaft 26 in slow speed V2, the curve of. velocities marks a corresponding fall ab by passing the curve

-2471244

  corresponding to. V to that corresponding to V2.

  During the advance, "work" of. each tool 17, which is done at low speed V2 of the geared motor unit 27, the velocity curve expresses the progressive slowdown obtained by modulating the speed of the shaft 26 between the points F2 and F3. This modulation is performed solely by the kinematics of the connecting rods 24 and the eccentrics 25 without using an expensive and complex device for electronically varying the speed of the

IO geared motor unit 27.

  At the end of the cut, the inversion of the direction of rotation and the speed change of the shaft 26 are translated on the velocity diagram by a jump c d of the curve

  lower than V2 at the upper curve cor-

  I5 corresponding to V1. The kinematics of eccentrics 25 and connecting rods-24 first increase this speed of recoil

  then slow down the increase in this speed, which

  dyes its maximum at the end of recoil tools 17 when

  are almost back to starting point E1., F1.

  8) - Interchangeability of tools according to the di-

  meters of the tubular piTèdes cut-off: Within certain limits, the same device of

  parting (ie the same spindle 8, the same system

  24-eccentric rod 25, the same tools 17 and the same articulated system 20-21) can receive parts of different diameters. For this purpose, the pin 8 remains the same, the only parts to change when changing diameter are the rings 13 and 14 and the annular elastic jaw 16. For cutting tools i7, just change their position by loosening the device 31, placing the lug 28 in-another notch 30 of the arm 20 or 21, which is closer to the axis XX if the diameter of the cut-off piece is smaller and further away if

  diameter is larger, and tighten the device 31.

- ADVANTAGES -

  Thanks to the profiling-cutting device of

2471244-

  invention, that is to say, thanks to the combination of the

  rod-crank (eccentric 25 and rods 24) and the articulated arm transmission system 20-21, and through the use of cutting tools 17, we obtain excellent cutting results (speed, absence of grazing, silence, very little wear of tools 17). These advantages

  are linked on the one hand to the removal of any

  tiline, cutting tools and, on the other hand,

  the progressive speed of the feed rate of each tool IO 17 and the slight change in the cutting angle as the tools penetrate into the material, this angle variation facilitating the removal of chips. This result is obtained while respecting a

  principle of simplicity of design.

  I5 - Another advantage results from the use of two diametrically opposed tools 17 which make it possible to cancel any radial reaction on the cut-off pipe 3: the two radial forces are balanced, and there is no reaction.

  on the device for driving the pipe in rotation.

-VARIANTES:

  We could only use one tool 17, one

  single arm 20 or 21, a single rod 24 and a single excen-

  25 But the cut-off time would be twice as long as in the case of the two cutting tools, and

  the advantage, the balancing of efforts

  cutting dials on the pipe. In addition, a rigid jaw clamping system should be used instead of the bit

  elastic ring 16 because of the risk of eccentricity.

  However, there may be around the pipe section. cutting more cutting tools 17, for example three tools 120 from each other or

  four tools arranged in two pairs diametrically oppo-

  This allows you to cut even more quickly.For this, we place on the motor shaft 26 one or two eccentric

  additional ones such as 25 and one o two connecting rods 24-.

  additional re.Iúées to one or two arms-additional such as' arms 20 and 21 each carrying one. tool 17 and

  articulated on a fixed shaft as judiciously

placed on the body of. pin 6.

  We can still remillo each tool 17 by a double tool with two cutting edges suitably

  offset in the circumferential direction, which makes

  come in total four cutting edges for the mode of

  realization at. two cutting tools.

  Of course, what has been described for the cutting of a cast iron pipe is applicable to that of a tube or other tubular part made of another rigid material such as steel, a rigid plastic material, asbestos- cement, etc.

Claims (9)

- CLAIMS -   1.- Method for cutting a tubular part driven in rotation about its axis and held stationary   in translation, characterized in that simultaneous attack   the cutting section by means of several cutting tools symmetrically distributed around this section and each having a cutting edge which is contained in an axial plane of the tubular piece and whose profile corresponds to the desired configuration for the end sectioned of this piece.   2. A process according to claim 1, characterized   rised in approaching the tools of the axis at a speed   gets fast until they come in contact with the piece then at a   slow speed during the penetration of the transverse ridges   sing in the wall of this piece, and when the cut I5 is finished, the tools are brought back to their position of start at fast speed.   3. A process according to claim 2, characterized   rised by gradually reducing the slow speed during the cut.   4. A process according to any of the claims   cations 1 to 3, characterized in that the angie is varied   attacking tools during the cut.   5.- Cut-off device for the implementation   process according to any of the claims   cations i to 4, for use with a machine   comprising means for clamping and driving rotationally   a tubular end to be cut and axial holding means of the piece, characterized in that it comprises a plurality of cutting tools (17) symmetrically distributed around the axis of rotation (XX) and each having a sharp edge (19) which is contained in a plane passing through this axis and whose profile corresponds to the desired configuration for the cut end of the workpiece (3), and a single drive shaft (26) two-way   rotation connected to. each tool (17) by an artificial system   abutment (25-24-20) transforming the circular motion into a   reciprocating motion at. almost rectilinear.   6. Device according to claim 5, characterized   in that the reciprocating motion is sinusoidal.   7. Device according to claim 6, characterized   characterized in that each tool (17) is mounted at the end of an arm of a two-armed oscillating lever (20, 21),   the other arm of this lever being connected to a connecting rod   IO crank (24-25) driven by the motor shaft (26).   8. Device according to claim 7, characterized   in that the crank-rod system (24-25) com-   carries an eccentric (25) wedged on the motor shaft (26) and   a connecting rod (24) articulated at one end on this excen-   15 and at the other end on the second arm of the swinging lever (20,21).   9.- Device according to any one of the   5 to 8, characterized in that the drive shaft (26) has two rotational axes and can be driven in one direction at high speed and then at low speed.   and in the other direction at fast speed.   10.- Device according to any one of the   5 to 9, characterized in that the cutting edge (19) of each tool (17) has a groove portion (CD) connected to a chamfering portion (AB) by a - rounded part (B).