DD236487A5 - TOOL AND METHOD FOR DRILLING A REAR STOVE HOLE - Google Patents

Abstract

The invention relates to a tool and a method for drilling a recessed hole, especially in walls of different materials, for attachment of fasteners. It is the object and the object of the invention to develop a tool of the simplest construction and operability, with which undercut holes can be produced, which are variable in their shape and their dimensions. The tool according to the invention essentially comprises a longitudinal tool body, at one end of which a pivotable blade is provided, which on the one hand has a cutting edge and on the other hand has a cam profile which is non-cutting and which can cooperate with a profiled body which is at the base of a conventional technique arranged first hole is to arrange. By exerting a slight axial pressure on the tool body and its abutment on a provided at the bottom of the wellbore profiled body pivoting of the blade is effected in accordance with the pressure used. Fig. 3

Description

Field of application of the invention

The present invention relates to a tool and method for drilling undercut holes.

Characteristic of the known technical solutions

The problem of drilling undercut holes or shoulder holes in concrete walls, cement or plaster walls or walls made of other materials, for example, to attach dowels and similar fasteners, could until today only be solved using extremely complicated tools. However, with such tools, the shapes and dimensions of the chambers inside the normal bores could not be practically varied. In addition, the operation of these tools can be extremely difficult.

Object of the invention

The aim of the present invention is to provide a tool and a method for drilling undercut holes, with which a tool of simplest construction is used, which is very versatile and very easy to use.

Explanation of the essence of the invention

The object of the invention is to provide a tool and a method by which undercut holes can be made by means of conventional drills and simple additional means allowing a variation of the shape and dimensions of the chambers located inside the normal bores.

The tool according to the present invention is characterized by at least one blade which is pivotally mounted about a transverse axis at the end of an elongated body, the blade having in addition to the necessary cutting edge a cam profile which can cooperate with a profiled body, which in turn at the bottom of usual borehole is arranged to pivot the blade arbitrarily different, in response to the force exerted on the elongated tool body axial force.

In a first embodiment of the profiled body is formed in the simplest way by a ball which is arranged at the bottom of the hole. The inventive method in this case is that first with a conventional, d. H. a hole is drilled in that hole, and that thereafter the blade of the tool of the present invention is brought into contact with the ball, of course by the tool being driven by means known per se, i. H. is rotated, and that on the tool an axial pressure is applied. The ball in this case fulfills three functions, namely:;

It prevents the tool from continuing to drill in the direction of the borehole axis,

It interacts with the cam-shaped portion of the blade and causes it to swing out,

- By having any degree of freedom to rotate, it can follow all the stresses of the blade during the operation, wherein the blade rotates about the longitudinal axis of the elongated body and pivots about said transverse axis.

In a second embodiment, the profiled body presents itself in the form of a tool-mounted element having a portion which serves as a cam and is retained in a recess provided at the end of the elongated body of the tool and in which the cam profile of the blade penetrates supporting itself against the portion formed as a cam and by an extension which extends beyond the end of the elongated body, along the axis of the latter, said extension in turn having at its free end a spherical portion which is intended to be against the Reason for the hole.

The method according to the invention in this case is to first drill a hole by means of a classical drill, then to insert the tool into this hole until said spherical section arrives at the bottom of the hole and during normal rotation of the tool axial pressure is applied.

If such a shoulder bore is completed or if the undercut hole or the chamber is executed, the tool can be withdrawn and removed by a simple axial train. In this approach, the blade, which protrudes approximately radially outward at the beginning, abut against the rear edge of the shoulder of the behind hole pierced and pivot by itself inward.

As already mentioned above, the tool according to the invention comprises a blade which is pivotally mounted about a transverse axis provided at the end of an elongated body, and means for giving the blade a variable inclination as soon as an axial pressure is exerted on the tool body. to move it beyond the point where the tool rests against the bottom of the hole. According to the invention, said blade has a profiled surface portion which performs the function of a cam, which in turn cooperates with a profiled surface portion of a body which abuts the bottom of the hole, the two said surface portions being formed such that the cutting portion of the blade is less axial displacement of the elongated body from its position in which it is substantially aligned axially, is pivoted to a position substantially transverse to it.

Because of this construction, the blade will perform a drilling operation in the reverse sense of axial pressure, allowing to obtain a relatively large chamber having a shoulder on the side opposite the bottom of the bore, i. a chamber which is particularly well suited to retain a Spreizdübel or ähliche fasteners.

In the case of the particularly advantageous embodiment, in which the body to be arranged at the bottom of the hole consists of a simple ball, it is possible according to the invention to form the end face of the elongated body, which has a slot for passing the blade, in such a way that it has a spherical recess, for example, has a shot-shaped recess for centering the ball.

This shallow recess facilitates, in particular, the re-centering of the ball, which cooperates with the blade, which is particularly of particular interest when a particularly preferred method is used, in which in a first operation a plurality of balls in a previously made in the classical manner wellbore are introduced until they are on top of each other at the bottom of the hole, then. The blade of the tool is brought into contact with the top or last introduced ball to drill in this position a first chamber section, then in a second step after the last Ball was removed, another chamber section is drilled, etc., until finally only the last ball remains at the bottom of the hole.

In this case, the axis of said recess and elongated body is preferably displaced with respect to the axis of rotation of the blade so that the lever action which causes the blade to pivot increases, particularly near the position in which the blade is transverse to the axis projects.

It is also possible to advance, for example, said slot with respect to the center of the end face of the elongate body to thereby reinforce the end portion of the elongated body on which the reaction force of the blade is supported during the operation.

Other embodiments of the tool according to the invention provide that the blade is provided on its two sides, namely at its pivotally hinged end, with two ball sections. As a result, a spherical body is formed, which engages in a recess arranged at the end of the tool. The active portion of the blade is passed through a slot. The tool may also include two blades which are pivotally mounted about a transverse axis at the end of the elongated body. Both blades interact with the same profiled body.

In all embodiments, the elongated body may be at least partially surrounded by a free-rotating ring. It may also be desirable to displace the axis of the spherical recess of the end face of the elongated body and the elongated body with respect to the axis of rotation of the blade to increase the leverage created for pivoting the blade, especially when the blade is near the blade transversely pivoted position is located. The slot in the end face of the elongated body may conveniently be offset with respect to the center of the end face to reinforce the end portion of the elongated body, as this affects the reaction force of the blade during its rotation about its axis.

A further advantageous embodiment of the tool may be that the two are separated by the slot portions of the end face of the elongated body on the side are connected to each other, which is opposite to the point at which swings the blade. The connection is realized by a metallic piece, which forms a kind of bridge, and enables

- The blade is blocked against pivoting in one direction of rotation, to prevent them from tilting and swinging to the wrong side,

- The two sections are reinforced to increase the resistance to undesirable spreading.

The piece is expediently integrally formed with the elongated body and / or is produced when working out of the slot. It can also consist of an attached piece of material. According to the invention, the piece may have an outer side surface which extends or forms the extension of the outer lateral shapes of the end face portions and forms a substantially spherical end face which forms a continuity in the shape transition with the spherical recess.

embodiment

Embodiments of the invention will be explained below with reference to exemplary embodiments illustrated in the drawings. In the accompanying drawing show:

Fig. 1 to 3: the schematic sequence of the method according to the invention according to a first embodiment;

Fig. 4: a particular embodiment of the blade of the tool, which with spherical sections, which

Form pivot axis, is provided;

Figures 5 and 6: the end of the tool in which the blade is installed; 7 is a longitudinal section through the tool, which is provided with channels to the worked out,

remove dusty material; 8 shows a further embodiment;

9 and 10: two further axial sections through another embodiment of the tool, which with two blades

is equipped;

 Fig. 11: a view of the active end of a tool according to another Äusführungsform, partially in section

along a median plane through the blade and the slot; Fig. 12 is an end view of the end portion of the tool of Fig. 11;

FIG. 13 shows the schematic method sequence when using a plurality of balls; FIG.

14 is a perspective, perspective view of the end portion of a tool according to FIGS. 11 and 12.

Fig. 1 of the drawing illustrates the first phase of the process in which a hole is drilled with a classical drill and then a ball B is brought to the bottom of the hole. In this first embodiment, the tool according to the invention has an elongated body C which has at its active end a blade L which is pivotally mounted about an axis X'X and which has a cam profile outside its cutting edge, which is supported on the ball B. , The tool is rotated about the longitudinal axis of the body C and a running parallel to the axis pressure exerted on the tool. The ball B first stops the blade L and prevents it from further drilling; On the other hand, it causes the blade L to pivot, and more so as the pressure increases. Fig. 3 of the drawing shows that the relatively strongly swung out blade L drills out a chamber whose shape forms a body of revolution about the longitudinal axis, and whose diameter depends on the axial force exerted on the tool and on the profile of the cut surface of the blade L. It is, of course, possible to carry out several subsequent drilling operations in the same hole to increase the depth of the recessed, recessed chamber.

The ball B may for example consist of steel and be brought out of the hole again at the end of the drilling process, for example by means of a flexible magnetic rod.

Of course, several technical possibilities are conceivable to attach the blade L at the end of the elongated body C.

One of these solutions is, for example, to provide a slot at the end of the elongate body C so that it allows the blade L to be accommodated. In this case, the pivot axis will pass through the two side walls of the cylindrical chamber and be fixedly disposed therein, for example by welding, pressing or other means known to those skilled in the art to prevent the two forked side members from bending during operation of the apparatus. Thanks to this arrangement thus the tool is much more stable.

In order to facilitate the insertion of the tool into the hole, the tool may comprise blocking means which rotate in a direction of rotation of the blade L, the latter preferably being in the axially aligned position, i. over the elongated body C projecting forward, is located. In the example described above, these blocking means can simply be that on the one hand on the blade L and on the other hand on the body C matching stop surfaces are present.

Fig. 4 shows a particularly advantageous embodiment of the blade L, which in the example shown on both sides, at the hinged end, with two spherical sections Li; L _{2 is} provided, which frame the end L ₃ , to form together with this a spherical body which extends into a corresponding recess at the end of the tool body

- Ο- / 9D OO

can be introduced and there, for example, purely mechanically, is held by a beading C ₂ , as shown in FIG.

From Fig. 5 it is apparent that the recess Ci before crimping its end C _{2 has} a cylindrical portion which is open at the extended end and is extended by a hemispherical portion. Fig. 6 shows that after the

Inserting the spherical body of the blade L into the recess Ci, the edge of the latter being crimped at its end,

to hold the body. A slot F (Figure 5), which runs along a generatrix of the elongate body C to the end of the latter, allows the passage of the blade L.

From Figure 4, the sectional area L _{t of} the blade L and the profiled section L ₀ , which forms a cam, visible.

Fig. 7 shows the tool body in longitudinal section. It can be seen that an axial channel C _a, the open recess Ci, in which the drilling dust can penetrate with evacuation channels C ₂ ; C3 is connected for discharging the material. These channels C ₂ ; C ₃ may be connected to flexible hoses (not shown) which extend them axially and in which the centrifugal force creates a negative pressure through which the drilling dust is sucked out of the hole. As a variant, it is also possible, as FIG. 7 shows schematically, to let a turbine wheel T rotate about the body C, specifically at the level of the channels C ₂ ; C ₃ , to enhance the suction effect.

Fig. 8 of the drawing shows a second embodiment in which the ball B is replaced by a fixedly connected to the body C of the tool element. This element has a portion which forms a cam E ₀ , and which is held in a recess at the end of the body C and an extension which protrudes from the recess at the end of the body C and carries at its end a ball E _b . It is clear that this ball E _{b will} be supported at the bottom of the hole, while the portion forming the cam E _{c will} bear on the cam profile of the blade L to the inclination of the blade L as a function of the applied axial pressure on the tool to change. In this embodiment, it is not necessary to arrange a lost ball at the bottom of the hole, which after each operation again

must be brought out. _

The invention is not limited to the use of a single blade L at the end of the elongate body C.

It is provided, for example, two blades ί _Ί ; Insert L ₂ , which are applied to the end of the elongated body C, insert, as shown in Figures 9 and 10. These two blades L ₁ ; L ₂ work together with a single, common profiled body (ball B).

The advantage of this solution is that the two blades Li; L ₂ work simultaneously and this on each side, so that the transverse stresses acting on the elongated body C, come virtually disappear. This gives a reduction of the friction forces acting on the body C.

Of course, other embodiments of the tool described are possible, in particular changes in the blade L with respect to their shape are conceivable. Such changes in the invention are purely of a professional nature.

For example, the elongate tool body C may be at least partially surrounded by a freewheel ring to eliminate the influence of frictional forces and consequently to reduce the wear of the tool body when touching the hole wall.

11 and 14, the active end portion of the tool body C is shown, with the blade L, which is arranged pivotably about an axis A. The cutting edge L _{T of} the blade L is extended, beyond the tip with a cam-like profile L _c , which cooperates with a ball B, which in turn must be placed at the bottom of the hole. When the method according to the invention is used, the blade L will increasingly incline in the direction of the arrow (Fig. 11) as soon as an axial force is exerted on the body C, and the cut surface Lt thus passes, already at one small axial displacement of the elongate body C, from an initial position in which it is substantially axially aligned, in an end position which is transverse to this axis, as shown in FIG. 11 shows.

In this way, around the axis of symmetry YY 'of the tool a rotary body-shaped chamber is drilled or broken out, by means of the cutting surface L ₁ , which is aligned in the opposite sense to the axial force. It should be noted that this boring is obtained by, on the one hand, rotating the tool about the axis YY 'and, at the same time, applying an axial pressure, without any impact, which distinguishes this method, in particular, from the drilling operation with the classical drill. As is apparent from Fig. 12, the blade louse out a slot Fin of the end surface of the tool body. In the described embodiment, this slot F is laterally displaced with respect to the center of the end face. As a result, the end portion of the body C receives a reinforced side to which the reaction force of the blade L during rotation of the tool about the axis YY 'affects. As a result, the risk of breakage of the blade L due to deformation of the tool surface on which it is supported, virtually eliminated.

Fig. 11 of the drawing shows the end face of the body C, in which a spherical recess C ₅ or recess is provided whose diameter is slightly larger than that of the ball B. This configuration of the end portion of the body C not only causes the centering of the ball B, but also ensures a stiff support of the blade L on the portions of the walls of the slot F, which project beyond the transverse plane, which runs tangentially to the bottom of said recess when the blade L relatively little inclined with respect to the axis YY 'runs.

Fig. 11 shows, moreover, that the axis A is displaced with respect to the axis of symmetry YY 'of the body C of the recess. It follows that even near the transverse position of the blade L, the reaction force exerted by the ball B at its point of contact with the blade L and the reaction force exerted by the axis A on the blade L still constitute a tilting moment for the blade L. ,

Fig. 13 of the drawing shows how a larger chamber is formed of a plurality of adjoining smaller chambers in the following way: a first portion CHi is obtained by cooperation of the tool with four balls B ₁ to B ₄ ', for example; the second section CH ₂ is obtained by means of a second step, in which the tool cooperates only with the balls B ₂ to B ₄ after the ball Bi has been removed beforehand, etc.

It is clear that in this procedure, the ball, which cooperates directly with the cam profile of the blade L, is centered by the spherical recess C _{3 of} the tool, while the other balls can be arranged more or less decentered without any adverse consequences.

Again, of course, mechanical changes of the tool are readily conceivable. This requires nothing more than the use of the specialist.

According to a particular embodiment of the invention, the two sections BR ₁ and BR _{2 of} the body C, which are separated from each other by the slot F, may be united with each other on the side opposite the location at which the blade L is to swing by means of a small metallic piece P (Fig. 11; 14), which forms a kind of bridge and which allows

- the unidirectionally rotating blade L is blocked in such a way that it can not swing over and extend in the wrong direction, and

- The two sections BR ₁ and BR _{2 are} reinforced by their expansion due to acting forces is prevented and thus the slot F can not open unduly.

The said metallic piece P can in principle form part of the body C itself and be obtained, for example, when working out the slot F. Of course, it can also be formed by an insert.

Preferably, it is formed and shaped to remain in the general line of the body C, and for this purpose preferably has, as shown, an outer side surface which defines the outer surfaces of the portions BR ₁ ; BR ₂ extended as well as an approximately spherical end surface, which also fits into the spherical recess Cs and extends its surface.

Claims (15)

Invention claim .: A tool for drilling undercut holes, characterized in that at least one drill blade (L) is pivotally mounted about a transverse axis (X'X) at the end of an elongate body (C), said blade (L) being external to its cutting edge (C). L,) has a cam profile (L _c ) which is intended to cooperate with a profiled body (B; E ₀ ; E _b ) which bears against the bottom of a hole, thereby swinging out the blade (L) to a different extent depending on the axial force exerted on the elongate body (C). 2. Tool according to item!, Characterized in that the blade (L) on its two sides, namely at its pivotally applied end (L ₃ ), with two ball sections (L ₁ , L ₂ ) is provided, which said end (L ₃ ) frame and together with the same form a spherical body (Li; L ₂ ; L ₃ ), which is intended to engage in a provided at the end of the tool recess (C ₁ ), while the active portion of the blade (L) through a slot (F) which extends along a generatrix of the tool body, to the end of the latter. 3. Tool according to item 1, characterized in that the profiled body (B; E _c ; Eb) is an element integrated in the tool, and has a portion (E _c ), which in a recess at the end of the elongated body ( C) of the tool to retained cam, wherein the cam profile of the blade (L) penetrates into said recess and against the one | Cam protruding portion, and further having an extension which projects beyond the end of said elongate body (C), in the direction of the axis of the latter, wherein the extension at its free end has a spherical portion (E _b ), which intended to abut the bottom of the hole. 4. Tool according to item 1, characterized in that it comprises two blades (L ₁ , L ₂ ) which are pivotally mounted about a transverse axis (X'X) at the end of the elongated body (C), wherein the two blades (L ₁ , L ₂ ) interact with the same profiled body (B). -2- / 30.50 5. Tool according to one or more of the items 1 to 4, characterized in that the elongated body (C) is at least partially surrounded by a free-rotating ring. 6. Tool according to item 1, characterized in that the one blade (L) has a profiled surface portion (L _c ), which takes over the function of a cam, which cooperates with a ball (B), which rests against the bottom of the hole said surface portion (L _c ) of the blade (L) is profiled such that the cutting portion (L _t ) already at a small axial displacement of the elongated body (C) from a substantially axial position in a substantially transverse to the axis Position is pivoted and that the end face of the elongated body (C) having a slot (F) for the passage of the blade (L) is shaped so that it has a spherical recess (Cs) for centering the ball (B) , 7. Tool according to item 6, characterized in that the axis (YY ') of the spherical recess (C ₅ ) and the elongated body (C) with respect to the axis of rotation (A) of the blade (L) is displaced, which for pivoting the Blade (L) leading leverage increases, especially when the blade (L) is in the vicinity of the transversely pivoted position. A tool according to item 6 or 7, characterized in that the slot (F) is offset with respect to the center (O) of the end face of the elongate body (C) to thereby soften the end portion of the elongate body (C), the reaction force the blade (L) during the rotation of the tool around its axis to reinforce. Tool according to at least one of the items 1 to 8, characterized in that the two sections (BR ₁ , BR ₂ ) of the body (C) which are separated from each other by the slot (F) are connected to one another on the side opposite the point on which the blade (L) swings out, by a metallic piece (P), which forms a kind of bridge and allows - The blade (L) is blocked against swinging in one direction to prevent them from tilting and swinging to the wrong side and - The two sections (BR ₁ , BR ₂ ) are strengthened to increase the resistance to undesirable spreading. 10. Tool according to item 9, characterized in that the piece (P) with the body (C) integrally formed and / or when working out of the slot (F) is obtained. 11. Tool according to item 9, characterized in that the piece (P) consists of an attached piece of material. 12. Tool according to one or more of the items 9 to 11, characterized in that the piece (P) has an outer side surface which extends the outer lateral shapes of the sections (BR ₁ ; BR ₂ ) or forms its extension and an in essential spherical end surface, which forms a continuity in the shape transition with the spherical depression (C _s ). 13. A method for drilling a hollowed-out hole using the tool according to item 1, characterized in that first a hole is drilled with a conventional drill, that then a said profiled body (B; E ₀ , E _b ) forming ball in the Hole is introduced and that thereafter the blade (L) of the tool is brought into contact with the ball, wherein the tool is rotated in a known manner and in that an axial pressure is exerted on the tool. · _% 14. A method for drilling a pierced hole using the tool according to item 3, characterized in that a hole is drilled with a conventional drill, then the tool is inserted into this hole until its spherical portion (E _b ) at the bottom of the hole arrives at that the tool body is rotated in a known manner and thereby an axial pressure is exerted on the tool. 15. A method for drilling a recessed hole according to item 13 and using the tool points, characterized in that a plurality of balls (B ₁ to B ₄ ) are introduced in a previously drilled in a known manner hole in a first method step, that thereafter the Tool is brought into contact with the last of these balls (B ₁ ) to form a first portion (CH ₁ ) of the hinterstochenen chamber, that thereafter in a second step and after removal of the last ball (B ₁ ), the procedure is repeated to form a second chamber section (CH ₂ ) directly following the former (CHi) and that the rest of the balls (B ₂ to B ₄ ) continue to move until only the last ball (B ₄ ) at the bottom of the hole located. For this 3 pages drawings