EP1535704B1 - Tool holder for a rotary percussion tool - Google Patents

Abstract

The chuck (1) includes a receiving sleeve (3) having a guide surface (12) extending along a longitudinal axis with a radial dimension (R), and at least three, axially extending, up to a free end surface of the chuck, entraining grooves (5) located in front of the guide surface. The entraining grooves are arranged radially outside of the radial dimension at angles of 0, 120, and 240 degrees and each having a central angle defined with respect to the radial dimension and amounting to at least 40 degrees. At least one locking member (5) is radially displaceable over the radial dimension and arranged between two circumferentially adjacent entraining grooves and diametrically opposite a third entraining groove.

Description

The invention refers to a tool holder for an at least partially rotating and / or hammering tool, such as a drill bit, chisel or cutting bit for machining stone, concrete or masonry, according to the preamble of claim 1 and as from EP 1508 391 A2 known.

Usually, a tool holder for a spigot end of a machine driven by a machine and driven by a hammer, for example, accordingly DE3941646A1 an insertion sleeve extending along an axis and having inner cylinder jacket-shaped guide surfaces and radially inwardly projecting rotary driving webs and radially inwardly displaceable locking bodies, which engage in locking grooves of the associated insertion end of the tool and limit the axial mobility of the tool. Due to the necessary for the transmission of a given torque to the tool high surface pressure with respect to the guide surfaces radially inwardly disposed rotary support webs are subjected to high wear, which limits the life of the tool holder. Especially when tool holders for hand tools used in construction, which process brittle materials such as concrete and masonry and produce abrasive overburden, a low wear of the tool holders for the reliability of the power tool is important.

After DE3843465A1 has such a tool holder two with respect to the guide surfaces radially inner Drehmitnahmestege and axially offset four with respect to the guide surfaces radially outwardly rotary drive grooves with a central Drehnutwinkel of 45 °. In particular, the heavily wearing, radially inward rotary driving webs limit the life of the tool holder. In addition, the remaining at the four symmetrically distributed rotational drive grooves central residual groove angle of 45 ° does not provide sufficient guide space for the radially displaceable locking body, which is arranged axially offset for this reason, which extends the tool holder unfavorably.

After DE19604283A1 has a further such tool holder in addition to the two with respect to the guide surfaces radially inner rotary driving webs in addition to three radially external rotary driving grooves, which are circumferentially distributed symmetrically. The partially with a central Drehnutwinkel smaller 30 ° narrow rotary driving grooves is necessarily associated with a Einsteckende with a narrow Drehitnahmeflügel smaller 30 ° fitting. Due to the disproportionate dependence of the circumferential bending stiffness of rotary driving blades whose elastic / plastic deformation would lead from a surface contact on a high-wear line contact, the surface pressure and thus the transferable per unit area torque of the tool holder is limited in such a narrow rotational drive wing.

The object of the present invention consists in the realization of a short tool holder, which can transmit high torques wear.

The object is essentially achieved by the features of claim 1. Advantageous developments emerge from the subclaims.

Thus, a tool holder for a longitudinal axis along an axis at least partially rotating and / or beating tool at a coaxial Radialbezugsmass, which corresponds to the inner radius, fully open receiving sleeve with a, at least partially with the Radialbezugsmass along the axis constantly extending, inner guide surface, at least three formed axially in the receiving sleeve, up to an axially free end face open, axially extending rotary driving grooves are axially extending at least at 0 °, 120 ° and 240 ° radially outside the Radialbezugsmasses, and at least one on the Radialbezugsmass radially displaceable Locking body, which is arranged circumferentially between two adjacent rotary driving grooves and diametrically opposite the third rotary driving groove, wherein a Radialbezugsmass certain central Drehnutwinkel the rotary driving grooves is at least 40 ° each.

By each at least 40 ° large central Drehnutwinkel the rotary driving grooves for a given torque to be transmitted and given contact surface of the rotary driving grooves always a sufficiently rigid rotary drive wing of a spigot end can be inserted, which does not deform significantly elastic / plastic.

This is particularly due to the addition of the essential wear-determining parameter, the circumferentially oriented contact surface available for torque transmission, about the central Drehnutwinkel the Drehmitnahmenuten or the associated rotary drive wing conditionally. This statement is subsequently justified by scale laws.

When machining rock, the highest torque peaks M occur at tool locks on the radial outer edge of the tool, which are thus proportional to the radius of the tool or the radial reference mass R of the associated insertion end, given a strength of the rock, whereby M / R is constant. On the other hand, behave at a length and angle true scaling of the cross section of the inventive tool holder for an associated insertion both the Radialbezugsmass R and the contact surface of the associated Drehmitnahmeflügels given length proportionally to the scale factor and thus the transmitted at a line load q torque M square to Radialbezugsmass R, where: M ~ q R ^ 2. The maximum line load of the contact surface pressure depends only on the material pairing. If one considers such an approximately rectangular, radially projecting, mass-loaded bending beam of a blade thickness d - R and a blade height h - R under the condition required for low-wear contact pairings of a HERTZ-type pressing of the rotary drive groove of the tool holder for the associated rotary drive wing, the line load q applies and the bending moment of inertia 1 - d ^ 3 - R ^ 3 for a maximum permissible elastic-plastic deflection in order to avoid line contact: y - qh ^ 4 / I ~ q R, which is constant. From this, M - q R ^ 2 - R follows with the above result, which therefore also satisfies M / R = constant. This free scalability of the both required and low-wearable transferable torque M with respect to the radial reference mass R is given only in the length- and angle-faithful scaling of the cross-section and in particular also on the incoming with the third power proportionality d-R, which a constant central Drehnutwinkel Are defined.

According to the invention, each rotational drive groove has a radial rotational force depth depth which is proportional to the radial reference mass R by a constant minimum gap dimension, optimally 0.8 mm in the value range from R / 6 to R / 3, more preferably exactly R / 4.5, whereby an associated insertion end of a blade height h which is linearly correlated with the circumferentially oriented contact surface available for torque transmission as substantially wear-determining parameter, is set to a tribologically suitable value range with respect to the material pairing for tool holders and axially impact-stressed tools in an abrasive environment.

Advantageously, each Drehitnahmenut above Drehmitnahmeuttiefe an axial Drehitnahmenutlänge of at least 30 mm, whereby the under HERTZ'scher pressing wear-transmissible torque is practically sufficient dimensioned.

Advantageously, the central Drehnutwinkel the rotary driving grooves in each case a maximum of 70 °, whereby between two circumferentially adjacent rotary driving grooves a sufficiently large central sleeve segment angle for guiding the radially displaceable locking body remains, which is symmetrical uniform distribution of exactly three rotational drive grooves at least 50 °.

Advantageously, the central sleeve segment angle between two circumferentially adjacent rotary drive grooves between 50 ° and 80 °, whereby the Radialbezugsmass R a stop web to the radial stop of a circular cross-section in axial cross-section with a, between two rotary driving wings of the insertion end associated locking groove substantially filling circular section of a diameter in the value range from 1.2 R to 1.8 R, further advantageously a diameter of 1.4 R, remains in the radially inner locking position.

Advantageously, the locking body is formed roller-shaped and oriented parallel to the axis, whereby axially a higher shear strength is given.

Advantageously, a plurality of locking bodies are present, optimally exactly three, whereby higher axial forces can be transmitted to the locked tool from the tool holder, in particular when pulling out of a borehole.

Advantageously, the rotary driving grooves on the machine side a circumferentially closed, innenzylindermantelförmiger Führungsendbereich the guide inner surface of the Radialführungsmasses R downstream, which are transferable to an associated, machine side end-side outer guide surface of the insertion high bending moments.

Advantageously, the leading end region has a guide length in the value range 1 R to 3 R, more preferably exactly 2 R, which can be done within this guide length a seal against the ingress of abrasive dust in the tool holder, further advantageous with a sealant such as a rubber lip seal.

• Fig. 1 als Werkzeugaufnahme im Längsschnitt
• Fig. 2 als Werkzeugaufnahme im Querschnitt
• Fig. 3 als Variante

The invention will be described in more detail with respect to several advantageous embodiments with:

• Fig. 1 as a tool holder in longitudinal section
• Fig. 2 as a tool holder in cross section
• Fig. 3 as a variant

To Fig. 1 has a tool holder 1 for a longitudinal axis A rotating and beating tool 2 on a coaxial Radialbezugsmass R fully open receiving sleeve 3 with a guide inner surface 12 which extends with the Radialbezugsmass R constant along the axis A. A machine-side leading end portion 13 of the guide inner surface 12 is axially upstream of a formed in the receiving sleeve 3, axially extending rotary driving groove 5, which is open to an axially free end face 4 out. The rotational drive groove 5 has an axial rotational drive groove length L of 40 mm, within which a roller-shaped and parallel to the axis A oriented, radially displaceable locking body 6 is arranged, which is arranged diametrically to the rotary driving groove 5 and in the illustrated locking position both inside and outside of the radial reference mass R extends. Downstream of the rotary driving groove 5 is the circumferentially closed, inner cylinder jacket-shaped machine-side leading end region 13 of the guide inner surface 12 with a guide length F of 2.0 R, which is assigned a sealant 10 in the form of a rubber lip seal for sealing against the ingress of abrasive dust into the tool holder 1.

To Fig. 2 has the tool holder 1 exactly three inside rotary driving grooves 5, which are rotationally symmetric at 0 °, 120 ° and 240 ° radially outside the radial reference mass R extend, and on the Radialbezugsmass R radially displaceable locking body 6, the circumference between two adjacent rotary driving grooves 5 and diametrically is disposed opposite to the third rotary driving groove 5. A Radialbezugsmass R specific central Drehnutwinkel α of the rotary driving grooves 5 is in each case 45 °. The respective remaining central sleeve segment angle β for guiding the radially displaceable locking body 6 is 75 °. Each rotational drive groove 5 has a radial rotational force depth H which is extended by a constant minimum gap dimension S of 0.8 mm and substantially proportional to 1 / 4.5 to the radial reference mass R. The roller-shaped locking body 6 of diameter D of 1.4 R strikes in its radially inner locking position on a to the Radialbezugsmass R extending stop web 11, wherein its cross-sectionally locking circular section an associated locking groove 7 between two rotary drive wings 8 of the insertion end 9 of the tool 2 substantially fills.

To Fig. 3 are in the tool holder 1 three spherical locking body 6 circumferentially symmetrically distributed, each disposed diametrically opposite a respective rotary driving groove 5. The spherical locking body 6 fill in cross section with their locking circular sections depending on an associated locking groove 7 of the insertion end 9 substantially. Since the insertion end 9 with a Radialbezugsmass R corresponding external diameter does not penetrate further into the thus free rotary driving grooves 5, in this variant, the rotational drive takes place exclusively via the locking grooves 7 of the insertion end. 9

Claims (9)

1. Tool holder for a tool (2) rotating and/or pulsating percussively at least partially along an axis (A), comprising a receiving socket (3) open over its full circumference with a coaxial radial reference dimension (R) and with an internal guide surface (12) extending constantly along the axis (A) at least partially with the radial reference dimension (R), axially ahead of which internal guide face (12) are positioned three axially disposed rotary entrainment grooves (5) which are formed in the internal face of the receiving socket (3) and are open up to an axially free end face (4), which rotary entrainment grooves (5) extend radially outside the radial reference dimension (R) at least at 0°, 120° and 240°, and with at least one locking body (6) which is displaceable radially over the radial reference dimension (R) and is arranged circumferentially between two adjacent rotary entrainment grooves (5), diametrically opposite the third rotary entrainment groove (5), the receiving socket (3) being open over its full circumference with respect to the coaxial radial reference dimension (R) and a central rotary groove angle (α) of the rotary entrainment grooves (5) defined at the radial reference dimension (R) being at least 40° in each case, characterised in that each rotary entrainment groove (5) has a radial rotary entrainment groove depth (H) which is increased by a constant minimum gap dimension (S) and is substantially proportional to the radial reference dimension (R) within the range of values from R/6 to R/3.
2. Tool holder according to Claim 1, characterised in that each rotary entrainment groove (5) has an axial rotary entrainment groove length of at least 30 mm, which optionally is 40 mm.
3. Tool holder according to any one of the preceding claims, characterised in that the central rotary groove angle (α) of the rotary entrainment grooves (5) is not more than 70° in each case.
4. Tool holder according to any one of the preceding claims, characterised in that a central socket segment angle (β) between two circumferentially adjacent rotary entrainment grooves (5) is from 50° to 80°.
5. Tool holder according to any one of the preceding claims, characterised in that the locking body (6) is circular in axial cross section and optionally has a diameter (D) within the range of values from 1.2 R to 1.8 R.
6. Tool holder according to Claim 5, characterised in that the locking body (6) is in the form of a roller and is oriented parallel to the axis (A).
7. Tool holder according to any one of the preceding claims, characterised in that a plurality of locking bodies (6) are present, optimally exactly three.
8. Tool holder according to any one of the preceding claims, characterised in that a circumferentially closed guide end region in the form of an internal cylindrical surface is positioned after the rotary entrainment grooves (5) on the machine side.
9. Tool holder according to Claim 5, characterised in that the guide end region (13) has a guide length (F) within the range of values from 1 R to 3 R, optionally 2 R.

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