EP1174225B1 - Percussion tool - Google Patents

Description

The invention refers to a tool, such as a drill bit or chisel, which is associated with an impact tool, such as a drill bit or chisel, which is at least partially hammering, such as a drill or chisel, preferably for working stone such as concrete and masonry.

A used as a tool drill bit is claimed by an at least partially hammering hammer, for example. With the striker and / or the flying piston of an electro-pneumatic striking mechanism, axially to the tool axis with mechanical shocks on the end face of the insertion, wherein the impact energy substantially via longitudinal pulses in shape propagates from shock pulses to the opposite end face and allows the output of the material to be machined energy editing. This opposite end face is usually designed as a carbide-tipped tool head.

From the physics of momentum transfer, it is known how an impulse splits with respect to the transition of two abutting bodies with respect to it, ie is transmitted or reflected. The proportion of energy coupled via the tool into the material to be processed depends on the acoustic properties of the bodies located in the pulse transmission chain, according to the bar theory describing the impulse response of rod-shaped solids. In the tool, the injected energy thus causes on the one hand a translational center of gravity movement and on the other hand a vibration about the center of gravity, wherein essentially only the translatory center of gravity movement is usable for processing.

After US4165790 is a tool in a plurality of non-rotatable and limited axially movable parts, eg. In a short tool head, a much longer tool shank and a spigot, divided, each one secured with a cross pin hexagon connection forms the form-fitting rotationally fixed and limited axially movable connection. After US4605079 has a very short such tool head on a hexagon socket for a form-locking rotationally fixed and limited axially movable connection. Such tool heads are not optimized with respect to the momentum transfer.

After WO97 / 08421 there is a drill bit at the end of a drill pipe or a drill rod, wherein the form-locking rotationally fixed and limited axially movable tool head itself forms a head part and a shaft part with respect to an arranged within its axial length face. The non-rotatable fixation via polygonal shaped cross-sectional areas or via engaging in recesses noses. About a light metal pin or a ring of the tool head is limited axially movable axially fixed to the drill pipe or the drill rod. The transmission of the impact pulse from the drill pipe or the drill rod to the tool head via perpendicular to the tool axis oriented, substantially flat formed impulse transmission surfaces, both between a drill pipe and radially outside and axially disposed within end faces of the tool head and between a drill rod and radially inside and axially disposed within disposed regions of a sleeve-shaped tool head.

According to the teaching of the above document, the ratio of the lengths of the shank part with respect to the head part is as large as possible, in particular greater than five, so that the maximum pulse energy can be transferred to the tool head for machining the material. In general, a certain impedance ratio of the shaft part to that of the head part is to be observed, wherein constructive, slight axial variations of the absolute values are permitted. An on the headboard part arranged in the headboard side end face of the drill pipe or the drill rod transmitted shock pulse with respect to the tool head double length is transmitted to a part of the short head directly into the material to be processed and the other part as a train pulse in the transmitted axially movable shaft part, which stores this pulse energy. Thus, in this solution, a tensile impact is transmitted to the tool head. After reflection at the side facing away from the headboard free end face of this is transformed as a shock pulse transmitted through the head in the material to be processed. As a result of the teaching of the transmission of the pulse energy of a shock pulse with respect to the tool head double pulse length in the tool head essentially no return pulse in the drill pipe or in the drill rod excited and thus the pulse energy almost completely in the tool head and thus in the material to be processed transfer. In such a solution, the momentum transfer of a pushrod is optimized in a tool head necessarily equipped with a shaft part, which works as a proper self-contained tool with firmly connected shaft part and head part of the material

The US1744141 discloses a tool adapted for processing rock by an associated percussion impact tool, wherein the shank of the tool abuts with a convex and the percussion means with a concave crowned face.

The object of the invention is to optimize the transmission of the pulse energy applied by the impact tool in the tool head of a structurally simple to manufacture tool. Another aspect is a suitable attachment of the tool head of such a tool.

The object is essentially achieved by the features of the independent claims. Advantageous developments emerge from the subclaims.

Essentially, in a, associated with a percussion tool, a tool with an acoustically long tool shaft rotatably connected and axially limited movable tool head with respect to its impedance acoustically matched to the flying piston and / or the striker of the striking tool device, each abutting faces respectively at least partially flat in contact with each other.

By such an acoustic adaptation is at a, with respect to the excited by the flying piston and / or striker shock pulse, acoustically adapted tool head, wherein the pulse length is equal to twice the acoustic length of the tool head, this shock pulse almost completely from the flying envelope and / or striker in the tool head transferred, without there being a significant back reflection and thus to a pulse energy loss.

By an at least partial, substantially planar contact between the respective Stosspartnern a piston applied, substantially rectangular, shock pulse during transport to the tool head is not significantly widened, causing this shock pulse while largely retaining its shape through the tool shaft wanders and the acoustic adjustment is transferred almost completely into the tool head.

This almost complete energy transfer of the pulse energy of the flying piston and / or anvil onto the tool head, which at least partially consumes this pulse energy for processing the material, leads to an increase in the processing power by 25 to, compared to a rigid standard system in relation to large-scale heavy tools 80%.

It must be emphasized that a limited axially movable tool head, even one with acoustically adapted geometry, for the knowledge and realization of the teaching of this invention just is not sufficient, since this doctrine only by the addition, only at a sufficient surface contact possible, substantially undeformed transmitted rectangular shock pulse of defined length achieved the essential effect of complete impulse transmission. As a result of this teaching rammed the tool head with the maximum transferable energy in the material to be processed.

The perpendicular to the axis of impact respectively abutting faces of flying pistons and / or striker, tool shank and tool head are to ensure a nearly central shock at a low allowable angular displacement of the Stosspartner advantageous with an effective crown of such a large effective contact radius provided that at the bumps not one Point contact according to the Hertzian pressure but a surface contact predominates, wherein the effective contact radius r _eff from the signed curves r ₁ , r _{2 of} the abutting faces determined by: $$\frac{1}{r_{\mathit{eff}}}=\left|\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="imgf0001.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}+\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="imgf0002.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\right|$$

Further advantageously, the signed curvatures r ₁ , r _{2 of} the abutting end faces are the same orientation, whereby even with a slight angular misalignment of the Stosspartner an almost central shock is present with surface contact. For this purpose, an end face is advantageously crowned concave and the associated end face convexly convex.

For the teaching of this invention, an infinitely large effective contact radius would be ideal, with approximately 25% of the increase in processing power being lost in the case of a practically realizable effective contact radius of more than 1 m, compared to an ideal areal contact.

wobei $$\frac{1}{r_{\mathit{eff}}}=\left|\frac{1}{r_1}+\frac{1}{r_2}\right|$$

wobei (L₁, L₂) die Längen-, (A₁, A₂) die Querschnittsflächenverhältnisse, E der jeweilige Elastizitätsmodul und p die jeweilige Dichte bezeichnen, wobei der Index 2 den angestossenen Körper kennzeichnet.Advantageously, the acoustic adaptation of the tool head to the flying piston and / or striker takes place with respect to the impedance according to: $$\frac{A_2}{{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="imgf0001.png"\; state="\{\{state\}\}">A</figure-callout>}}_1}=\sqrt{\frac{e_1}{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="imgf0002.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}*\frac{{\mathrm{<figure-callout\; id="1"\; label="\rho "\; filenames="imgf0001.png"\; state="\{\{state\}\}">\rho </figure-callout>}}_1}{{\mathrm{<figure-callout\; id="2"\; label="\rho "\; filenames="imgf0002.png"\; state="\{\{state\}\}">\rho </figure-callout>}}_2}}$$

in which $$\frac{1}{r_{\mathit{eff}}}=\left|\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="imgf0001.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}+\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="imgf0002.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\right|$$

where (L ₁ , L ₂ ) denote the length, (A ₁ , A ₂ ) the cross-sectional area ratios, E the respective modulus of elasticity and p denote the respective density, wherein the index 2 denotes the impacted body.

When using the same materials thus essentially the same cross section of the flying piston and / or striker, tool shank and tool head must be complied with. If other dimensions are necessary for constructive constraints, in addition to the body geometry, for example, the material of the flying mass of usually steel, for example, can be advantageously substituted into a light ceramic or carbon fiber composite material.

Necessary constructive embodiments of tool head, flying piston and / or striker must be based at least substantially on such a geometry without being strictly prismatic. In the case of real deviations of approx. 10% each, approx. 25% of the increase in processing capacity is lost.

The tool itself consists of a tool shank and a rotatably limited axially movable tool head with cutting edges of hard material, the tool shank acoustically long and the tool head is acoustically tuned to the flying piston and / or striker. In the advantageous case of the same material of striker, tool shank and tool head whose cross sections are the same.

The coupling region of the tool shank adjacent to the tool head is advantageously of prismatic design, the cross section advantageously having the shape of a regular polygon, for example a hexagon. The edges are advantageously broken over a chamfer. The tool head, which forms the matching prismatic counterpart, is fastened in a rotationally form-fitting manner via the connection that forms as a result. A guided transversely to the tool axis both through the tool head and through the tool shaft pin provides a fixation means in conjunction with an axial slot in at least one of the parts a smooth, limited axial mobility safely.

Advantageously, the tool shank is made hollow, wherein a fluid medium such as rinsing liquid can be passed through the channel formed. The channel has inlet and outlet openings at the insertion end and in the tool head, wherein a limited axially movable, advantageously annular, sealing element is advantageously arranged between the tool shank and the axially movable tool head limited.

In a first advantageous embodiment variant, the tool head, which is acoustically matched with respect to its length and its cross section, is provided with a sleeve-like region assigned to the tool shank, in which the tool shank engages in a rotationally fixed and limited axially movable manner. The necessary, at least in part essentially planar design of the end face between the tool shank and the tool head is realized via an inner annulus area with a very large effective radius of curvature. An optional sealing element is advantageously designed as a radially smaller, centrally offset part of the tool shank, which ends in a central bore in the cutting edge region of the tool head, of which at least one opening leads to the end face of the tool head, which advantageously offset eccentrically to the tool axis outside the head groove arranged to clear the abraded material adjacent to the cutting edge. As a fixing means is a transversely through an axial slot of the sleeve-like portion of the tool head and through a hole in the tool shaft guided pin.

In a second advantageous embodiment variant, the tool head, which is acoustically matched with respect to its length and cross section, is provided with a radially smaller, centrally offset region associated with the tool shank with a driving nose arranged in the radially outer, which engages in the tool shank in a rotationally fixed and limited axially movable manner. The necessary, at least partially substantially planar design of the end face between the tool shank and the tool head is realized via an outer annulus area with a very large effective radius of curvature. An optional sealing element is advantageously arranged on this centrally offset region, which has a central bore which terminates in an area of the tool head assigned to the cutting edge, from which at least one opening leads to the end face of the tool head, which is advantageously offset eccentrically from the tool axis outside the head groove Spacing the removed material is arranged adjacent to the cutting edge. As a fixing means is either a transversely through a chord-like running hole in the tool shaft and a arranged in the driving lug of the tool head axial slot guided pin or in a third advantageous variant in a circumferential groove in the tool shank fixed spring ring, which in a radially outer recess arranged Engaging nose of the tool head engages.

The fixing means also advantageously allow a modular replacement of the tool head, which easily replaces this wear part as well as a machining task optimally adapted tool head can be mounted from a selection set out.

• Fig. 1 als Prinzip eines stossimpulsoptimierten Werkzeugs für ein zugeordnetes Schlagwerkzeuggerät
• Fig. 2 als Werkzeug in Schnittdarstellung
• Fig. 3 als eine erste Ausführungsvariante des Werkzeugs in Explosionsdarstellung
• Fig. 4 als zweite Ausführungsvariante des Werkzeugs in Explosionsdarstellung
• Fig. 5 als eine dritte Ausführungsvariante des Werkzeugs in Explosionsdarstellung

The invention will be explained in more detail with respect to an advantageous embodiment with:

• Fig. 1 as a principle of a shock pulse-optimized tool for an associated impact tool device
• Fig. 2 as a tool in a sectional view
• Fig. 3 as a first embodiment of the tool in an exploded view
• Fig. 4 as a second embodiment of the tool in exploded view
• Fig. 5 as a third embodiment of the tool in an exploded view

According to FIG. 1, in an illustration with an acoustic length and width dimension, a percussion tool device 1, which is shown only partially schematically, is associated with a tool 2 which has an acoustically long tool shank 3 and an axially limited movable tool head 4. The tool head 4 is acoustically adjusted with respect to its impedance to a reciprocating flying piston 5 and an anvil 6 of the impact tool device 1. The tool head 4 is adjusted with respect to a shock pulse 7 whose pulse length is equal to twice the acoustic length of the tool head 4, whereby this shock pulse 7 is almost completely transmitted from the flying piston 5 on the striker 6 and the tool shaft 3 in the tool head 4, which in a later time essentially rammed with the full pulse energy in a rock to be machined 8, without causing a significant back reflection 9 and thus to a pulse energy loss during the transfer to the tool head 4. In the transmission of the shock pulse 7, the abutting each end faces 10 are each in planar contact with each other, whereby the shock pulse 7 is transmitted substantially as a rectangular pulse.

According to Fig. 2, the cut along the tool axis not fully illustrated tool 2 itself consists of a tool shank 3 and a rotatably limited axially movable tool head 4 with cutting edges 11 made of hard material, in the illustrated case the same material of the tool shank 3 and 4 tool head whose cross-sectional areas substantially are the same. The tool head 4 adjacent coupling portion 12 of the tool shank 3 is formed prismatic. The tool head 4 forms for this purpose the appropriate prismatic counterpart. A guided transversely to the tool axis both by the tool head 4 and by the tool shank 3 pin provides as a fixing means 13 in conjunction with an axial slot as Fixierungsaufnahme 14 in the tool head 4 a smooth, limited axial mobility .DELTA.x safe. The mutually associated in the transmission of the shock pulse at least partially in surface contact associated end faces (10) are arranged perpendicular to the tool axis (not shown) executed with an effective crowning greater 1 m. The tool shank is hollow. A channel 15 forming inside, which opens into a central bore in the cutting edge 11 associated region of the tool head 4 ends, has (partially not shown) inlet and outlet ports 16 at the insertion or in the tool head 4, wherein in an axial sealing region 17 between the tool shaft 3 and the limited axially movable tool head 4 a limited axially movable annular sealing element 18 is arranged.

According to Fig. 3 the acoustically tuned with respect to its length and its cross-section tool head 4 is designed sleeve-like, the hexagonal prismatic coupling portion 12 of the tool shank 3 rotatably and limited axially movable engages in a matching counterpart forming tool head 4. The at least partially substantially planar design of the end face 10 between the tool shank 3 and the tool head 4 is realized via an inner annulus area with a very large effective radius of curvature. An annular sealing element 18 is arranged circumferentially around a radially small, centrally offset sealing region 17 of the tool shank 3, which engages in a central bore of the tool head 4, from which two outlet openings 16 each lead to an end face of the tool head 4, which offset eccentrically to the tool axis outside a head groove 19 for clearing the removed material and adjacent to the cutting edge 11 is arranged. As fixing means 13 is a pin which is guided transversely to the tool axis by a designed as an axial slot fixation receptacle 14 of the coupling portion 12 of the sleeve-like tool head 4 and through a hole in the tool shank 3.

According to FIG. 4, the tool head 4 which is acoustically matched with respect to its length and cross section is provided with a radially smaller, centrally offset coupling region 12 associated with the tool shank 3 with a driving lug 20 arranged in the radial outer, which rotates and limits in the tool shank 3 designed as a counterpart axially movable engages. The at least partially substantially planar design of the end face 10 between the tool shank 3 and the tool head 4 is realized via an outer annular region with a very large effective radius of curvature. An annular sealing element 18 is arranged on the centrally offset sealing region 17 which adjoins the coupling region 12 and which has a central bore which ends in a bore of the tool head assigned to the cutting edge 11, from which two outlet openings 16 lead to one end face of the tool head 4 which is advantageously arranged eccentrically offset from the tool axis outside the head groove 19 for clearing the removed material and adjacent to the cutting edge 11. As a fixing means 13 is a pin which transversely through a chord-like running hole in the tool shank 3 and by a in the driving lug 20 of the tool head 4 arranged axial slot is performed as fixing receptacle 14.

5 serves as a fixing means 13 in a circumferential groove 21 in the tool shank 3 fixed spring ring, which engages in a radially outwardly arranged recess of the driving lug 20 of the tool head 4 as a fixing receptacle 14.

Claims (9)

1. Tool with an acoustically long tooling (3), formed for the processing of stone (8), masonry and the like by an assigned impact tool appliance (1) exhibiting an impact tool (5, 6), where the frontal surfaces (10) of the impact tool (5, 6) and of the tooling (3) impacting in each case on each other exhibit an effective amount of crown, characterised by a tool head (4) torsionally linked with the tooling (3) and with axially limited movement, which in regard to its impedance is acoustically suited to the impact tool (5, 6) of the impact tool appliance (1), with the acoustic length of the tool head (4) amounting to half the length of the knock impulse (7) reached by the impact tool.
2. Tool according to claim 1, characterised by the fact that the tool head (4) is mutually linked with the tooling (3) via a prismatically shaped rotational form closing coupling range (12).
3. Tool according to claim 2, characterised by the fact that inside the coupling range (12) a fixing device (13) extending transversely to the tool axis both through the tool head (4) and also through the tooling (3) is fitted within an axially longitudinal fixing holder (14) of the tool head (4) and/or of the tooling (3).
4. Tool according to claim 3, characterised by the fact that the fixing device is shaped as a pin or a ring.
5. Tool according to one of the foregoing claims, characterised by the fact that the tooling (3) is made hollow and exhibits in- or outlet openings at a plug-in end and in the tool head (4) and that between the tooling (3) and the tool head (4) with limited axial movability a sealing element (18) with limited axial movability is fitted.
6. Impact tool appliance for at least partial striking stressing of a tool (2) according to one of the foregoing claims, characterised by the fact that the free piston (5) is made of a lighter and/or less stiff material in respect of steel.
7. Tool and/or impact tool appliance according to one of the foregoing claims, characterised by the fact that the acoustic adaptation of the free piston (5) and/or of the anvil (6) and/or of the tool head (4) in respect of the acoustic impedance occurs in each case through a suitable dimensioning of the essential length and of the essential cross sectional area.
8. Tool and/or impact tool appliance according to one of the foregoing claims, characterised by the fact that the frontal surfaces (10) in each case at least partly knocking against each other are made perpendicular to the axis of impact and are also provided with an effective amount of crown with an effective radius of contact of at least 1 m.
9. Tool and/or impact tool appliance according to claim 8, characterised by the fact that with two frontal surfaces (10) assigned to each other in each case one is formed spherically concave and the other spherically convex.

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