FR2514676A1 - DISCHARGE DRILLING TOOL FOR FORMING FLANGES ON METAL PLATES - Google Patents

Abstract

THE INVENTION RELATES TO PUNCHING TOOLS. IT RELATES TO A DRILLING TOOL IN WHICH A FLAT BODY 3 IS MOUNTED ON A CYLINDRICAL ROD 2. THE UPPER PART OF THE BODY 3 FORM A SHOULDER AND THE SHOULDER, THE SIDES AND BOTTOM EDGE OF THE BODY CARRY BANDS OF SINKED CARBIDE 7, 8. THE DRILLING AND FORMATION OF A COLLAR IS PROVIDED SIMPLY BY SUPPORT AND FRICTION FORCES. APPLICATION TO THE DRILLING OF HOLES SURROUNDED BY FLANGES IN METAL PLATES AND TUBES.

Description

The present invention relates to a chuck

  designed to be rotated around its axis

  dinal, at high speeds, so that it forms a hole surrounded by a flange in a metal sheet or tube wall exclusively under the action of pressure and heat due to friction, the mandrel comprising a cylindrical rod for to be mounted in a rotating drive mandrel, a shoulder and a working portion contiguous to the shoulder and having a width which determines the diameter of the hole, this working portion having a portion which has a width which decreases on the side of

  the opposite end to the cylindrical rod.

  Tools of this type, forming push-back drilling tools, are already known, as described in German Patent No. 2,359,794. In the known tool for push-back drilling, in addition to the push rod

  to be clamped by a chuck of a training tool

  tation, the shoulder also has a cylindrical shape while the working part adjacent to the collar has a

  substantially triangular section with rounded corners.

  German Patent No. 2,552,665 discloses a similar push-back drilling tool. In this tool, the triangular general configuration has been abandoned and the circumference of the working part is determined.

  in section, by arcs having different radii of curvature

  fers, these arches connecting to each other.

  Drilling tools are made by

  of the aforementioned type of sintered carbide, whose machining is extremely difficult, and the relatively elaborate configuration can be obtained only by rectification, starting from

  of a cylindrical rod The manufacture of the tools of

  by repression having practically the same ne-

  a great deal of experience and the rectification

It is also expensive.

  The invention relates to a push-back drilling tool of the aforementioned type which is very simple and

  much less expensive than the corresponding tools.

251467 f

  known for this purpose, the recess drilling tool

  according to the invention is characterized in that

  the shoulder and the working part of the mandrel are de-

  limited by two parallel flat surfaces, the thickness of the working part being at most equal to half of the greatest width of the working part, the other surfaces delimiting the working part being rounded, their radius of curvature being less than the

  half the width of the working part.

  The thickness of the working part is

  less than or equal to one-third of its greater width. It has been assumed until now that the discharge piercing tool should have a shape ensuring an automatic centering, that is to say must have at least three edges in contact with the wall of the hole to be drilled so that the general shape of the mandrel, in section, had to be triangular It is surprisingly found that the supposed difficulties of centering do not appear in the case of a flat-shaped mandrel Thus, during the manufacture of tools for drilling by pushing, a plate of sintered carbide material can be used, only the sides and the lower edge of the mandrel

  must be rectified because these parts must be

  rounded to the desired form The reduction in the costs of

  and machining is very important The resulting savings

  Cost aunt is at least 30% A flat mandrel can then be suitably fastened in a rod

  cylindrical so that the tool can be tightened by the man-

  tightening of a rotating drive.

  Pressure piercing tools having

  flat side surfaces are already known as

  written in French Patent No. 1,189,384, but these drilling tools do not form a collar The working part of this known mandrel has a square configuration section, the diagonal being equal to the diameter of the hole to be drilled, the four edges of the tool being in contact with the wall of the hole 251467 g drill so that it is not a flat mandrel of

type according to the invention.

  The advantages obtained with the flat tool

  can be considerably increased.

  by producing the mandrel in two different materials.

  The lower edge of the shoulder and the sides of the

  In this case, the working mandrel is preferably formed of sintered carbide strips attached to a T-shaped body of a different material. The sintered carbide marginal strips may be connected to the flat faces of the T-mandrel body for example by welding with arpert, and they can also be connected to the sides and the lower edge of the mandrel body formed of a material

different, by an adhesive.

  The carbide tapes on the sides of the mandrel body can also be formed by vapor deposition In this case, not only the sides of the body of the

  chuck but still the entire surface of this one

  they receive a carbide coating.

  When the holes must have a large diameter, for example greater than 15 mm, it may be necessary for the shoulder and the working part of the mandrel to be formed of three connected members arranged

  radially and each having the shape of a body of man-

  T-piece separated along the central axis so that the rigidity

  increased, marginal bands of sintered carbide

  being attached to the sides and bottom edge.

  The flat discharge drilling tool may comprise, in place of a shoulder, grooves of

  same width as the mandrel part which has

  Such a mandrel allows the drilling of the hole and the drilling

  tapping in one operation.

  Other features and advantages of the

  will be better understood when reading the description of

  following examples of implementation and referring to

  rant in the accompanying drawing in which: Figure 1 shows a flat tool for drilling by pushing according to the invention;

  Figure 2 is a section along the line II-

  II of Figure 1; FIGS. 3 and 4 are sections similar to FIG. 2 of variants in which the mtar-

  are fixed to the mandrel body in a di -

  ferent; Figure 5 is a section similar to Figure 2 of a mandrel body having a carbide coating formed by vapor deposition; Figure 6 is a perspective view of a star-shaped mandrel according to the invention;

  FIG. 7 is a section along line VII-

  VII of Figure 6; and FIG. 8 shows a drilling tool by

  repression which is also appropriate for the formation of a

  dage. FIG. 1 shows a mandrel or tool 1 for the discharge bore which comprises a cylindrical rod 2 to which a T-mandrel body 3 has been fastened. This body 3 has a wide shoulder 4 and a working portion contiguous to the shoulder and whose lower end 6 has a pointed configuration The body 3, apart from the rod 2, may be formed of a metal carbide FIG. 1 represents an advantageous embodiment in

  which the body 3 is formed of a material which must only

  It should be sufficiently rigid while the lower edge of the shoulder 4 has carbide strips 8 and the sides of the body 3 also have carbide strips 7. These strips 7 must be folded approximately in their center so that they follow Inclined edge of the body 3 The strips 7 may be made so that they correspond to a body 3 of the shape shown. When the strips 7 and 8 have been applied to the sides and to the lower edge of the body of the mandrel, they may be rounded to the

desired form by rectification.

  The strips 7 and 8 of carbide can be fixed

  at the sides and at the bottom edge of the body 3 by an adhesive.

  In FIG. 2, an adhesive layer placed between the carbide strip and the working portion of the body is located

by the reference 12.

  The carbide strips 7 can also be connected with

  strung to the working part 5 of the body of another

  as shown in Figure 3 In this embodiment

  The flat strips 7 'of carbide are soldered onto the side faces of the body, the welding method used being of a type such as the formed weld.

  withstands high temperatures

  Figure 4 represents another embodiment of

  The sides of this portion 5 'have forked ends in which are fixed

strips 7 '.

  The above-mentioned push-back tools are all suitable for forming holes up to about mm (in materials whose resistance to

  tensile strength can reach 1.2 Pa (10 Pa). In the case of di-

  large meters or a very hard material, the drilling tool must have a higher rigidity This increased rigidity can be obtained by connecting parts 10 of the body in the form of half T <see Figure 6) along an edge lateral so that the mandrel body has a star shape, carbide strips that can be applied

  on the sides as previously described.

  It should be noted that the carbide strip placed at the lower edge of the shoulder 4 may be formed so that the collar to be made around the bore hole has a cavity as described in the German patent.

No. 2,802,229.

  The strips 7, 8 of carbide, carried out previously

  and secured to a chuck body formed of a

  different shape as shown in FIGS. 1 to 4 may be replaced by deposition of vapor-phase carbide on a support 5 "(see FIG. 5) by a method

  Chemical vapor deposition 511 is

  covered on all its surface with a layer of carbides 11,

  only the active sides to be rectified so that the

he has the proper form.

  push-through tools having a shoulder for leveling the upper face of the collar formed around the drilled hole are used, so that the upper face can be used as

  sealing surface In a second operation, a

  is formed in the drilled hole The flat tools of

  pressure drilling are very suitable for

  Hole and tapping in one operation In this case, the shoulder of the tool must be removed because the leveling of the

  the collar formed around the hole can not be

  at the same time as the formation of the thread.

  FIG. 8 shows a discharge piercing tool of this type. A flat body 3 is attached to a rod 2 and has a pointed lower end.

  7 of carbide are attached to this body in the manner

  Naturally, it is also possible to use the embodiment shown in FIG. The carbide strips 7 are then ground so that, at the upper part, they comprise grooves 13 allowing the formation of Tapping Part 14 which is contiguous to the flutes 13 has a shape of width which decreases slightly downward, following

  an angle of about 30 preferably. The formation of the

  raking, after the formation of the hole, is then facilitated.

  Even when the tool does not have splines 13, the working part of the mandrel preferably has such a

  width varying at an angle of 3 D so that the removal

  the chuck of the drilled hole is facilitated.

  Of course, various modifications can be made by those skilled in the art to the devices which have just been described as examples only.

  limiting without departing from the scope of the invention.

Claims (5)

  1 Discharge drill chuck designed to be rotated about its longitudinal axis, at high speed, so that it forms a hole surrounded by a flange in a metal sheet or the wall of a pipe only under the action of the pressure and heat due to friction, said mandrel being of the type which has a cylindrical rod to be clamped by a rotating drive mandrel, an enlarged shoulder and a working portion contiguous to the shoulder and having a width which determines the diameter of the hole, the working part having a decreasing width ready from its lower end, said mandrel being characterized in that the shoulder (4) and the working part (5, 6) are delimited by two surfaces parallel planes, the thickness of the working part (5) being at most equal to half the largest width of the working part (5), the other surfaces defining the part   are rounded with an inferior radius of curvature   half the width of the working part (5). Mandrel according to Claim 1, characterized   in that the thickness of the working part is at the maximum   mum equal to one third of the greatest width of this part.   3 Discharge drill chuck, comprising a cylindrical rod to be clamped by a chuck of a rotating drive tool, an enlarged shoulder, and a working portion contiguous to the shoulder and having a width which determines the diameter of the hole, the part   whose width decreases near its end.   lower, the shoulder and the working portion being delimited by two parallel flat surfaces, the thickness of the working portion being at most equal to one-third of the greatest width of this portion, said mandrel   characterized in that the lower edge of the shoulder   and the sides of the working part of the mandrel are formed by sintered carbide strips fixed to a   T-shaped body made of a different material.   Mandrel according to Claim 3, characterized   in that the strips (7, 8) of sintered carbide are   roped to the flat sides of the body (3) T by soldering. Chuck according to Claim 3, characterized in that the strips (7, 8) of sintered carbide on the sides are connected to the sides and the lower edge of the body T-mandrel with adhesive -   6 Discharge drill chuck comprising a cylindrical rod to be clamped by a rotating drive mandrel, an extended shoulder and a   work area contiguous to the shoulder and whose   geur determines the diameter of the hole, the working part   having a width that decreases near its lower end   the shoulder and the working part being   two parallel flat surfaces, the thickness of the working part being at most equal to one third of the greatest width of this part, said mandrel being characterized in that it comprises a body (5 ") T coated on all its surface with a carbide coating (11).   Mandrel according to Claim 3, characterized in that the shoulder (4) and the working part (5) of the mandrel are formed by three connected members (10) arranged in a star-shaped configuration, each member having the shape of a body ( 3) of T-mandrel, separated along its central axis, marginal bands (7, 8) of sintered carbide being fixed   at the sides and at the lower edge of the body.