EP3898117B1 - Handheld chiselling machine tool - Google Patents

Handheld chiselling machine tool Download PDF

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Publication number
EP3898117B1
EP3898117B1 EP19812801.9A EP19812801A EP3898117B1 EP 3898117 B1 EP3898117 B1 EP 3898117B1 EP 19812801 A EP19812801 A EP 19812801A EP 3898117 B1 EP3898117 B1 EP 3898117B1
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EP
European Patent Office
Prior art keywords
segment
die
tool
axis
working axis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP19812801.9A
Other languages
German (de)
French (fr)
Other versions
EP3898117A1 (en
Inventor
Rory Britz
Rainer Ontl
Markus Hartmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hilti AG
Original Assignee
Hilti AG
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Publication date
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Publication of EP3898117A1 publication Critical patent/EP3898117A1/en
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Publication of EP3898117B1 publication Critical patent/EP3898117B1/en
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Anticipated expiration legal-status Critical

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D17/06—Hammer pistons; Anvils ; Guide-sleeves for pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D11/00—Portable percussive tools with electromotor or other motor drive
    • B25D11/005—Arrangements for adjusting the stroke of the impulse member or for stopping the impact action when the tool is lifted from the working surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2211/00—Details of portable percussive tools with electromotor or other motor drive
    • B25D2211/003—Crossed drill and motor spindles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2211/00—Details of portable percussive tools with electromotor or other motor drive
    • B25D2211/06—Means for driving the impulse member
    • B25D2211/068—Crank-actuated impulse-driving mechanisms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D2217/0011—Details of anvils, guide-sleeves or pistons
    • B25D2217/0015—Anvils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D2217/0011—Details of anvils, guide-sleeves or pistons
    • B25D2217/0023—Pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2250/00—General details of portable percussive tools; Components used in portable percussive tools
    • B25D2250/131—Idling mode of tools

Definitions

  • the present invention relates to a chiseling hand tool such as a hammer drill or an electric chisel.
  • a hammer drill according to the preamble of claim 1 is made, for example US 9,339,924 B2 known.
  • the hammer drill has an electro-pneumatic impact mechanism.
  • a user turns on an electric motor of the rotary hammer by pressing a button.
  • the percussion mechanism should only be activated when the user presses the hammer drill, more precisely a tool, against a substrate.
  • the electric motor continuously moves an exciter piston of the percussion mechanism.
  • a hammer of the hammer mechanism is coupled to the movement of the exciter piston via a pneumatic chamber when ventilation openings in the pneumatic chamber are closed.
  • the ventilation openings are controlled by a gun.
  • the die is placed on the working axis between the hammer and the tool.
  • the die When the percussion mechanism is pressed, the die is moved into a working position in the direction of the hammer. In the working position, the ventilation openings are closed and the impact mechanism is active. If there is no pressure, a hit of the club, a so-called empty shot, ensures that the deadbolt leaves the working position. The ventilation openings are released and the striking mechanism switches off.
  • the deadbolt moves in the direction of impact due to the empty shot.
  • a catcher catches the dopper.
  • the snapper comes to a standstill preferably through the catcher.
  • the striker may bounce off the catcher, slide back into the working position, and undesirably activate the hammer mechanism, closing the vents.
  • the next beat is a blank again.
  • the blank impacts represent a considerable burden for the hand-held power tool and the user, since the entire impact energy is absorbed within the hand-held power tool and is not directed into the ground as desired.
  • US 9,339,924 B2 describes a deadbolt with a front face that is eccentric relative to the catcher.
  • the eccentric face is intended to cause the die to rotate, thereby extracting kinetic energy from the die.
  • the Döpper then no longer reaches the working position.
  • the solution described depends on tolerance-free guidance of the die in order to ensure the eccentric arrangement.
  • the die and its guide are subject to a high level of wear due to the entry of dust and drill cuttings via the tool, which affects the accuracy of the guide.
  • the eccentric arrangement influences the efficiency of the transmission of the shock wave from the die to the axially arranged tool.
  • the chiseling hand tool has the features of claim 1, it has a tool holder, a striking mechanism and a blank impact catcher.
  • the tool holder can hold a tool and hold it movably on a working axis.
  • the hammer mechanism includes an exciter piston, a hammer, a beater and a guide for the beater.
  • the beater couples to the movement of the exciter piston via a pneumatic chamber.
  • the striker is arranged on the working axis in the direction of impact from the bat.
  • the guide guides the die on the working axis.
  • the deadbeat catcher for the deadlock has a conical inner surface facing the deadlock.
  • the die has an associated end face that is inclined relative to the working axis and points in the direction of impact.
  • the face abuts the conical inner surface when the striker is in its most advanced position in the direction of strike.
  • the face of the die has a first segment and a second segment in the circumferential direction. The second segment is offset in the direction of flap compared to the first segment. The offset in the two segments of the face causes the deadbolt to tilt when it comes into contact with the empty-blow catcher. The tilting leads to the die jamming in the guide tube. Simulations show additional deflection of the beater due to the axial offset between the opposing contact points of the beater and catcher. This increases the stopping effect of the catcher on the snap.
  • the hammer drill has a tool holder 2, in which a tool 3 can be used and locked.
  • the tools 3 can, for example, be drill bits for turning and chiseling processing of mineral building materials, such as concrete or rock, or chisels for purely chiseling processing of the same building materials.
  • the rotary hammer 1 contains a pneumatic percussion mechanism 4 which periodically exerts impacts on the tool 3 in the impact direction 5 during operation.
  • the hammer drill 1 contains an output shaft 6 which rotates the tool holder 2 and thus the tool 3 about a working axis 7 during operation.
  • the percussion mechanism 4 and the output shaft 6 are driven by a motor 8, for example an electric motor.
  • the output shaft 6 can be switched off in chiseling handheld power tools 1 or in purely chiseling handheld power tools 1 are without an output shaft.
  • the hand-held power tool 1 has a handle 9, by means of which the user can hold and guide the hand-held power tool 1 during operation.
  • the handle 9 is attached to a machine housing 10 .
  • the handle 9 is preferably arranged at an end of the hand-held power tool 1 or of the machine housing 10 which is remote from the tool holder 2 .
  • a working axis 7 parallel to the direction of impact 5 and running centrally through the tool holder 2 preferably runs through the handle 9 if it is to be gripped with one hand.
  • the handle 9 can be partially decoupled from the machine housing 10 by damping elements in order to dampen vibrations of the percussion mechanism 4 .
  • the user can start up the hand-held power tool 1 using a button 12 . Pressing the button 12 activates the motor 8.
  • the button 12 is preferably arranged on the handle 9 , as a result of which it can be actuated by the hand gripping the handle 9 .
  • the percussion mechanism 4 has an exciter piston 13, a hammer 14 and a striker 15.
  • the exciter piston 13, the hammer 14 and the striker 15 are arranged one after the other on the working axis 7 in the direction of impact 5 .
  • the exciter piston 13 is coupled to the motor 8 via a gear train.
  • the gear train converts the rotational movement of the motor 8 into a periodic forward and backward movement of the exciter piston 13 on the working axis 7 .
  • An exemplary gear train is based on an eccentric wheel 16 and a connecting rod 17. Another embodiment is based on a wobble drive.
  • the beater 14 is coupled to the movement of the exciter piston 13 by a pneumatic chamber 18, also referred to as an air spring.
  • the pneumatic chamber 18 is closed along the working axis 7 on the drive side by the exciter piston 13 and on the tool side by the hammer 14 .
  • the beater 14 is designed as a piston.
  • the pneumatic chamber 18 is closed off in the radial direction by a guide tube 19 .
  • the exciter piston 13 and the beater 14 slide airtightly against the inner surface of the guide tube 19.
  • the exciter piston can be cup-shaped.
  • the beater slides inside the exciter piston.
  • the racquet can be cup-shaped, with the exciter piston sliding within the racquet.
  • the beater 14 moves, coupled via the pneumatic chamber 18 , periodically parallel to the impact direction 5 between a drive-side reversal point and a tool-side reversal point.
  • the reversal point on the tool side is specified by the snap die 15 , on which the beater 14 strikes at the reversal point on the tool side.
  • the die 15 is movably guided parallel to the impact direction 5 between a stop 20 and the tool 3 .
  • the user presses the tool 3 against the die 15 and indirectly the die 15 against the stop 20.
  • the position of the die 15 resting against the stop 20 is referred to as the working position.
  • the impact of the beater 14 on the die 15 preferably takes place when the die 15 is in the working position.
  • the striker 15 serves as an intermediary for the impact of the hammer 14 on the tool 3. A damping of the impact by the striker 15 is not desirable.
  • the die 15 slides in a tubular guide 21 on the working axis 7.
  • the working axis 7 is defined by the cylindrical inner surface 22 of the guide 21 .
  • the inner surface 22 is arranged coaxially to the working axis 7 .
  • the die 15 has a cylindrical lateral surface 23 which bears against the inner surface 22 .
  • the lateral surface 23 typically defines the largest diameter of the die 15.
  • the lateral surface 23 defines a longitudinal axis or die axis 24 of the die 15.
  • the die axis 24 corresponds to the axis of symmetry of the die Lateral surface 23. Due to the guidance 21 of the die 15 via the leading lateral surface 23 , the die axis 24 lies on the working axis 7.
  • the striker 15 has a striking surface 25 which points in the direction of the racquet 14 .
  • the racquet 14 hits the striking surface 25 .
  • the surface area of the striking surface 25 is typically less than the surface area of a cross section in the area of the leading lateral surface 23.
  • the striking surface 25 is preferably rotationally symmetrical to the die axis 24.
  • the hammer 14 thus strikes the striking surface 25 in the middle , which ensures more efficient energy transfer.
  • the striking surface 25 can be of planar design; a crowned design is preferred. In the illustrated embodiment, the striking surface 25 is followed by a cylindrical section whose diameter corresponds to the diameter of the striking surface 25 .
  • the die 15 has an impact surface 26 which points in the direction of the tool 3 , ie in the direction of impact 5 and is averted from the hammer 14 .
  • the striker 15 bears against the tool 3 with the abutting surface 26 or hits the tool 3 with the abutting surface 26 .
  • the surface area of impact surface 26 is typically less than the surface area of a cross-section in the area of leading lateral surface 23.
  • Impact surface 25 is rotationally symmetrical to die axis 24. Impact transmission from die 15 to tool 3 takes place centrally from impact surface 26.
  • Impact surface 26 can be flat or crowned.
  • the abutment surface 26 is adjoined by a cylindrical section 27 whose diameter corresponds to the diameter of the abutment surface 26 .
  • the snap die 15 rests against the stop 20 in the working position.
  • the stop 20 can be designed as a ring, for example.
  • the ring has an inside diameter that is slightly larger than the diameter of the face 25 .
  • the snap die 15 has a (rebound impact) surface 28 .
  • the impact surface 28 preferably has a conical shape.
  • the diameter of the die 15 increases uniformly along the die axis 24 from the smaller diameter of the striking face 25 to the diameter of the leading lateral surface 23.
  • the bounce face 28 is rotationally symmetrical to the die axis 24.
  • An inclination of the bounce face 28 relative to the die axis 24 and thus also in relation to the working axis 7 is preferably constant along the die axis 24 .
  • the stop 20 can also have a conical surface facing the rebound impact surface 28 .
  • the stop 20 can be supported in the machine housing 10 via a damping element 29, for example an elastic O-ring.
  • the snap die 15 moves only slightly out of its working position. After the beater 14 hits the die 15, the die 15 moves as far as the tool 3 moves out of the tool holder 2 at most. Due to the contact pressure exerted by the user, the tool 3 is pushed back into the tool holder until the snap die 15 rests against the stop 20 .
  • a (blank strike) catcher 30 stops the striker 15 in the direction of impact 5.
  • the striker 15 strikes the catcher 30 with an end face 31 .
  • the snap die 15 is then in its most advanced position in the direction of impact 5 .
  • the die 15 is tilted somewhat in relation to the guide 21 when the die 15 hits the blank strike catcher 30 , ie the die axis 24 is tilted in relation to the working axis 7 .
  • the tilting causes the die 15 to jam in the guide 21, as a result of which kinetic energy of the die 15 is reduced and the die 15 preferably comes to a standstill.
  • the tilting is achieved by a special asymmetry of the end face 31 of the snap die 15 .
  • the end face 31 points in the direction of impact 5 and is inclined relative to the die axis 24 .
  • the impact surface 25 connects the lateral surface 23 with the impact surface 26.
  • the diameter of the die 15 reduces from the maximum diameter of the leading lateral surface 23 to the diameter of the impact surface 26.
  • the special feature of the end face 31 is its subdivision in the circumferential direction 32 into a first segment 33 and a second segment 34.
  • both segments 33, 34 can be conical.
  • the first segment 33 is offset in the direction of impact 5 in relation to the second segment 34 .
  • the two segments 33, 34 are inclined relative to the die axis 24 and the working axis 7 .
  • the offset is reflected in the fact that for a section of the end face 31 at a constant radial distance from the working axis 7, the portion of the section associated with the first segment 33 is closer to the abutment surface 26 than the portion of the section associated with the second segment 34
  • the first segment 33 thus strikes first in the direction of impact 5 .
  • a portion of the first segment 33 ranges from 200 degrees to 270 degrees.
  • the second segment 34 is preferably cone-shaped.
  • An axis of the full cone forming the second segment 34 preferably coincides with the die axis 24 .
  • the first segment 33 can also be cone-shaped. One corresponding axis does not coincide with the die axis 24 .
  • the axis can be offset parallel to the die axis 24 or canted.
  • a radius of curvature r1 of the first segment 33 is larger than the radius of curvature r2 of the second segment.
  • the flatter first segment 33 can take up a larger proportion of the circumference than the steeper second segment 34.
  • the blank firing catcher 30 is formed, for example, by a conical narrowing of the guide 21 .
  • the constriction has an inner diameter which is larger than the diameter of the impact surface 26 of the die 15 but less than the diameter of the lateral surface 23 of the die 15 .
  • the constriction has a conical inner surface 37 which faces towards the die 15 .
  • the conical inner surface 37 is preferably rotationally symmetrical to the working axis 7.
  • the front, first segment 34 causes a larger radial force component compared to the flat segment 33.
  • die 15 is tilted or bent. Both effects lead to efficient braking of the die 15. This also occurs when the guide 21 of the die 15 parallel to the working axis 7 already has greater play due to wear.
  • the guide 21 can be rigidly anchored in the machine housing 10 .
  • the exemplary guide 21 is suspended in a damped manner in the impact direction 5 .
  • the guide 21 can be located in a slide bearing 38 .
  • a damping element 39 for example an elastomer, is clamped between a stop 40 fixed to the housing and a nose 41 .
  • the stop 40 is arranged by the nose 41 in the impact direction 5 .
  • the first segment 33 can be formed by a flat or almost flat bevel.
  • a radius of curvature r1 of the first segment 33 is correspondingly very large.
  • the first segment 33 has a smaller proportion of the circumference, for example between 30 degrees and 45 degrees.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)

Description

GEBIET DER ERFINDUNGFIELD OF THE INVENTION

Die vorliegende Erfindung betrifft eine meißelnde Handwerkzeugmaschine, z.B. einen Bohrhammer oder einen Elektromeißel.The present invention relates to a chiseling hand tool such as a hammer drill or an electric chisel.

Ein Bohrhammer nach dem Oberbegriff des Anspruchs 1 ist beispielsweise aus US 9,339,924 B2 bekannt. Der Bohrhammer hat ein elektro-pneumatisches Schlagwerk. Ein Anwender schaltet einen Elektromotor des Bohrhammers durch Betätigen eines Tasters ein. Das Schlagwerk soll nur jedoch nur aktiviert sein, wenn der Anwender den Bohrhammer, genauer ein Werkzeug, an einen Untergrund presst. Der Elektromotor bewegt kontinuierlich einen Erregerkolben des Schlagwerks. Ein Schläger des Schlagwerks wird an die Bewegung des Erregerkolbens über eine pneumatische Kammer angekoppelt, wenn Belüftungsöffnungen der pneumatischen Kammer geschlossen sind. Die Belüftungsöffnungen werden durch einen Döpper kontrolliert. Der Döpper ist auf der Arbeitsachse zwischen dem Schläger und dem Werkzeug angeordnet. Beim Anpressen des Schlagwerks wird der Döpper in eine Arbeitsstellung, in Richtung zu dem Schläger verschoben. In der Arbeitsstellung sind die Belüftungsöffnungen geschlossen und das Schlagwerk aktiv. Bei fehlendem Anpressen sorgt ein Schlag des Schlägers, ein sogenannter Leerschlag, dafür, dass der Döpper die Arbeitsstellung verlässt. Die Belüftungsöffnungen sind freigegeben und das Schlagwerk schaltet ab.A hammer drill according to the preamble of claim 1 is made, for example US 9,339,924 B2 known. The hammer drill has an electro-pneumatic impact mechanism. A user turns on an electric motor of the rotary hammer by pressing a button. However, the percussion mechanism should only be activated when the user presses the hammer drill, more precisely a tool, against a substrate. The electric motor continuously moves an exciter piston of the percussion mechanism. A hammer of the hammer mechanism is coupled to the movement of the exciter piston via a pneumatic chamber when ventilation openings in the pneumatic chamber are closed. The ventilation openings are controlled by a gun. The die is placed on the working axis between the hammer and the tool. When the percussion mechanism is pressed, the die is moved into a working position in the direction of the hammer. In the working position, the ventilation openings are closed and the impact mechanism is active. If there is no pressure, a hit of the club, a so-called empty shot, ensures that the deadbolt leaves the working position. The ventilation openings are released and the striking mechanism switches off.

Der Döpper bewegt sich aufgrund des Leerschlags in Schlagrichtung. Ein Fänger fängt den Döpper auf. Der Döpper kommt vorzugsweise durch den Fänger zum Stehen. Allerdings kann der Döpper von dem Fänger abprallen, zurück in die Arbeitsstellung gleiten und unerwünschter Weise die Belüftungsöffnungen schließend das Schlagwerk aktivieren. Typischerweise ist gleich der nächste Schlag wieder ein Leerschlag. Die Leerschläge stellen eine erhebliche Belastung für die Handwerkzeugmaschine und den Anwender dar, da die gesamte Schlagenergie innerhalb der Handwerkzeugmaschine aufgenommen wird und nicht wie gewünscht in den Untergrund eingeleitet wird.The deadbolt moves in the direction of impact due to the empty shot. A catcher catches the dopper. The snapper comes to a standstill preferably through the catcher. However, the striker may bounce off the catcher, slide back into the working position, and undesirably activate the hammer mechanism, closing the vents. Typically, the next beat is a blank again. The blank impacts represent a considerable burden for the hand-held power tool and the user, since the entire impact energy is absorbed within the hand-held power tool and is not directed into the ground as desired.

US 9,339,924 B2 beschreibt einen Döpper mit einer gegenüber dem Fänger exzentrischen Stirnfläche. Die exzentrische Stirnfläche soll ein Drehen des Döppers bewirken, wodurch dem Döpper kinetische Energie entzogen wird. Der Döpper erreicht daraufhin nicht mehr die Arbeitsstellung. Die beschriebene Lösung ist abhängig von einer toleranzfreien Führung des Döppers, um die exzentrische Anordnung zu gewährleisten. Allerdings unterliegt der Döpper und dessen Führung durch den Eintrag von Staub und Bohrgut über das Werkzeug einem hohen Verschleiß, worunter die Genauigkeit der Führung leidet. Ferner beeinflusst die exzentrische Anordnung die Effizienz der Übertragung der Stoßwelle von dem Döpper auf das axial angeordnete Werkzeug. US 9,339,924 B2 describes a deadbolt with a front face that is eccentric relative to the catcher. The eccentric face is intended to cause the die to rotate, thereby extracting kinetic energy from the die. The Döpper then no longer reaches the working position. The solution described depends on tolerance-free guidance of the die in order to ensure the eccentric arrangement. However, the die and its guide are subject to a high level of wear due to the entry of dust and drill cuttings via the tool, which affects the accuracy of the guide. Furthermore, the eccentric arrangement influences the efficiency of the transmission of the shock wave from the die to the axially arranged tool.

OFFENBARUNG DER ERFINDUNGDISCLOSURE OF THE INVENTION

Die meißelnde Handwerkzeugmaschine gemäß der Erfindung hat die Merkmale des Anspruchs 1, sie hat einen Werkzeughalter, ein Schlagwerk und einen Leerschlag-Fänger. Der Werkzeughalter kann ein Werkzeug aufnehmen und auf einer Arbeitsachse beweglich haltern. Das Schlagwerk beinhaltet einen Erregerkolben, einen Schläger, einen Döpper und eine Führung für den Döpper. Der Schläger koppelt über eine pneumatische Kammer an die Bewegung des Erregerkolbens an. Der Döpper ist in Schlagrichtung von dem Schläger auf der Arbeitsachse angeordnet. Die Führung führt den Döpper auf der Arbeitsachse. Der Leerschlag-Fänger für den Döpper hat eine dem Döpper zugewandte, konische Innenfläche. Der Döpper hat eine zugehörige, gegenüber der Arbeitsachse geneigte und in die Schlagrichtung weisende Stirnfläche. Die Stirnfläche liegt an der konischen Innenfläche an, wenn der Döpper in seiner in Schlagrichtung am weitesten vorgerückten Stellung liegt. Die Stirnfläche des Döppers hat in Umfangsrichtung ein erstes Segment und ein zweites Segment. Das zweite Segment ist gegenüber dem ersten Segment in Schlagrichtung versetzt. Der Versatz in den beiden Segmente der Stirnfläche führt dazu, dass der Döpper beim Anliegen an dem Leerschlag-Fänger verkippt. Das Verkippen führt zu einem Verklemmen des Döppers in dem Führungsrohr. Simulationen zeigen ein zusätzliches Verbiegen des Döppers aufgrund des axialen Versatzes zwischen den gegenüberliegenden Kontaktpunkten von Döpper und Fänger. Hierdurch erhöht sich die Stoppwirkung des Fängers auf den Döpper.The chiseling hand tool according to the invention has the features of claim 1, it has a tool holder, a striking mechanism and a blank impact catcher. The tool holder can hold a tool and hold it movably on a working axis. The hammer mechanism includes an exciter piston, a hammer, a beater and a guide for the beater. The beater couples to the movement of the exciter piston via a pneumatic chamber. The striker is arranged on the working axis in the direction of impact from the bat. The guide guides the die on the working axis. The deadbeat catcher for the deadlock has a conical inner surface facing the deadlock. The die has an associated end face that is inclined relative to the working axis and points in the direction of impact. The face abuts the conical inner surface when the striker is in its most advanced position in the direction of strike. The face of the die has a first segment and a second segment in the circumferential direction. The second segment is offset in the direction of flap compared to the first segment. The offset in the two segments of the face causes the deadbolt to tilt when it comes into contact with the empty-blow catcher. The tilting leads to the die jamming in the guide tube. Simulations show additional deflection of the beater due to the axial offset between the opposing contact points of the beater and catcher. This increases the stopping effect of the catcher on the snap.

KURZE BESCHREIBUNG DER FIGURENBRIEF DESCRIPTION OF THE FIGURES

Die nachfolgende Beschreibung erläutert die Erfindung anhand von exemplarischen Ausführungsformen und Figuren. In den Figuren zeigen:

Fig. 1
einen Bohrhammer
Fig. 2
einen Döpper des Bohrhammers
Fig. 3
ein Schnitt in Ebene III-III durch den Döpper
Gleiche oder funktionsgleiche Elemente werden durch gleiche Bezugszeichen in den Figuren indiziert, soweit nicht anders angegeben.The following description explains the invention using exemplary embodiments and figures. In the figures show:
1
a hammer drill
2
a hammer drill
3
a cut in plane III-III through the die
Elements that are the same or have the same function are indicated by the same reference symbols in the figures, unless otherwise stated.

AUSFÜHRUNGSFORMEN DER ERFINDUNGEMBODIMENTS OF THE INVENTION

Fig. 1 zeigt als Beispiel einer meißelnden Handwerkzeugmaschine 1 schematisch einen Bohrhammer. Der Bohrhammer hat einen Werkzeughalter 2, in welchen ein Werkzeug 3 eingesetzt und verriegelt werden kann. Die Werkzeuge 3 können beispielsweise Bohrer für die drehmeißelnde Bearbeitung von mineralischen Bauwerkstoffen, wie Beton oder Gestein, oder Meißel für die rein meißelnde Bearbeitung der selben Bauwerkstoffe sein. Der Bohrhammer 1 enthält ein pneumatisches Schlagwerk 4, welches im Betrieb periodisch Schläge in Schlagrichtung 5 auf das Werkzeug 3 ausübt. Zudem enthält der Bohrhammer 1 eine Abtriebswelle 6, welche im Betrieb den Werkzeughalter 2 und damit das Werkzeug 3 um eine Arbeitsachse 7 dreht. Das Schlagwerk 4 und die Abtriebswelle 6 werden von einem Motor 8, z.B. einem Elektromotor, angetrieben. Die Abtriebswelle 6 kann in meißelnden Handwerkzeugmaschinen 1 abschaltbar sein oder in rein meißelnden Handwerkzeugmaschinen 1 sind ohne Abtriebswelle. 1 1 schematically shows a hammer drill as an example of a chiseling hand-held power tool 1 . The hammer drill has a tool holder 2, in which a tool 3 can be used and locked. The tools 3 can, for example, be drill bits for turning and chiseling processing of mineral building materials, such as concrete or rock, or chisels for purely chiseling processing of the same building materials. The rotary hammer 1 contains a pneumatic percussion mechanism 4 which periodically exerts impacts on the tool 3 in the impact direction 5 during operation. In addition, the hammer drill 1 contains an output shaft 6 which rotates the tool holder 2 and thus the tool 3 about a working axis 7 during operation. The percussion mechanism 4 and the output shaft 6 are driven by a motor 8, for example an electric motor. The output shaft 6 can be switched off in chiseling handheld power tools 1 or in purely chiseling handheld power tools 1 are without an output shaft.

Die Handwerkzeugmaschine 1 hat einen Handgriff 9, mittels welchem der Anwender die Handwerkzeugmaschine 1 im Betrieb halten und führen kann. Der Handgriff 9 ist an einem Maschinengehäuse 10 befestigt. Vorzugsweise ist der Handgriff 9 an einem von der Werkzeughalter 2 entfernten Ende der Handwerkzeugmaschine 1 bzw. des Maschinengehäuses 10 angeordnet. Eine zu der Schlagrichtung 5 parallele und mittig durch den Werkzeughalter 2 verlaufende Arbeitsachse 7 verläuft vorzugsweise durch den Handgriff 9, wenn dieser einhändig zu greifen ist. Der Handgriff 9 kann durch Dämpfelemente von dem Maschinengehäuse 10 teilweise entkoppelt sein, um Vibrationen des Schlagwerks 4 zu dämpfen.The hand-held power tool 1 has a handle 9, by means of which the user can hold and guide the hand-held power tool 1 during operation. The handle 9 is attached to a machine housing 10 . The handle 9 is preferably arranged at an end of the hand-held power tool 1 or of the machine housing 10 which is remote from the tool holder 2 . A working axis 7 parallel to the direction of impact 5 and running centrally through the tool holder 2 preferably runs through the handle 9 if it is to be gripped with one hand. The handle 9 can be partially decoupled from the machine housing 10 by damping elements in order to dampen vibrations of the percussion mechanism 4 .

Der Anwender kann die Handwerkzeugmaschine 1 mittels eines Tasters 12 in Betrieb nehmen. Das Betätigen des Tasters 12 aktiviert den Motor 8. Der Taster 12 ist vorzugsweise an dem Handgriff 9 angeordnet, wodurch dieser von der den Handgriff 9 umgreifenden Hand betätigt werden kann.The user can start up the hand-held power tool 1 using a button 12 . Pressing the button 12 activates the motor 8. The button 12 is preferably arranged on the handle 9 , as a result of which it can be actuated by the hand gripping the handle 9 .

Das Schlagwerk 4 hat einen Erregerkolben 13, einen Schläger 14 und einen Döpper 15. Der Erregerkolben 13, der Schläger 14 und der Döpper 15 sind in Schlagrichtung 5 aufeinanderfolgend auf der Arbeitsachse 7 liegend angeordnet. Der Erregerkolben 13 ist über einen Getriebestrang an den Motor 8 angekoppelt. Der Getriebestrang setzt die Drehbewegung des Motors 8 in eine periodische Vor- und Rückbewegung des Erregerkolbens 13 auf der Arbeitsachse 7 um. Ein beispielhafter Getriebestrang basiert auf einem Exzenterrad 16 und einem Pleuel 17. Eine andere Ausführung basiert auf einem Taumelantrieb.The percussion mechanism 4 has an exciter piston 13, a hammer 14 and a striker 15. The exciter piston 13, the hammer 14 and the striker 15 are arranged one after the other on the working axis 7 in the direction of impact 5 . The exciter piston 13 is coupled to the motor 8 via a gear train. The gear train converts the rotational movement of the motor 8 into a periodic forward and backward movement of the exciter piston 13 on the working axis 7 . An exemplary gear train is based on an eccentric wheel 16 and a connecting rod 17. Another embodiment is based on a wobble drive.

Der Schläger 14 wird an die Bewegung des Erregerkolbens 13 durch eine pneumatische Kammer 18, auch als Luftfeder bezeichnet, angekoppelt. Die pneumatische Kammer 18 ist längs der Arbeitsachse 7 antriebsseitig durch den Erregerkolben 13 und werkzeugseitig durch den Schläger 14 abgeschlossen. Der Schläger 14 ist dazu als Kolben ausgebildet. In der dargestellten Variante ist die pneumatische Kammer 18 in radialer Richtung durch ein Führungsrohr 19 abgeschlossen. Der Erregerkolben 13 und der Schläger 14 gleiten luftdicht anliegend an der Innenfläche des Führungsrohrs 19. In anderen Ausgestaltung kann der Erregerkolben topfförmig ausgebildet sein. Der Schläger gleitet innerhalb des Erregerkolbens. Analog kann der Schläger topfförmig ausgebildet sein, wobei der Erregerkolben innerhalb des Schlägers gleitet. Der Schläger 14 bewegt sich angekoppelt über die pneumatische Kammer 18 periodisch parallel zu der Schlagrichtung 5 zwischen einem antriebsseitigen Umkehrpunkt und einem werkzeugseitigen Umkehrpunkt. Der werkzeugseitige Umkehrpunkt ist durch den Döpper 15 vorgegeben, auf welchen der Schläger 14 im werkzeugseitigen Umkehrpunkt aufschlägt.The beater 14 is coupled to the movement of the exciter piston 13 by a pneumatic chamber 18, also referred to as an air spring. The pneumatic chamber 18 is closed along the working axis 7 on the drive side by the exciter piston 13 and on the tool side by the hammer 14 . For this purpose, the beater 14 is designed as a piston. In the variant shown, the pneumatic chamber 18 is closed off in the radial direction by a guide tube 19 . The exciter piston 13 and the beater 14 slide airtightly against the inner surface of the guide tube 19. In another embodiment, the exciter piston can be cup-shaped. The beater slides inside the exciter piston. Similarly, the racquet can be cup-shaped, with the exciter piston sliding within the racquet. The beater 14 moves, coupled via the pneumatic chamber 18 , periodically parallel to the impact direction 5 between a drive-side reversal point and a tool-side reversal point. The reversal point on the tool side is specified by the snap die 15 , on which the beater 14 strikes at the reversal point on the tool side.

Der Döpper 15 ist parallel zu der Schlagrichtung 5 zwischen einem Anschlag 20 und dem Werkzeug 3 beweglich geführt. Im Betrieb drückt der Anwender beim Anpressen des Werkzeugs 3 an einen Untergrund das Werkzeug 3 gegen den Döpper 15 und mittelbar den Döpper 15 gegen den Anschlag 20. Die Stellung des Döppers 15 anliegend an dem Anschlag 20 wird als Arbeitsstellung bezeichnet. Der Schlag des Schlägers 14 auf den Döpper 15 erfolgt vorzugsweise, wenn der Döpper 15 in der Arbeitsstellung ist. Der Döpper 15 dient als Mittler des Schlags des Schlägers 14 auf das Werkzeug 3. Eine Dämpfung des Stoßes durch den Döpper 15 ist nicht erwünscht.The die 15 is movably guided parallel to the impact direction 5 between a stop 20 and the tool 3 . During operation, when the tool 3 is pressed against a substrate, the user presses the tool 3 against the die 15 and indirectly the die 15 against the stop 20. The position of the die 15 resting against the stop 20 is referred to as the working position. The impact of the beater 14 on the die 15 preferably takes place when the die 15 is in the working position. The striker 15 serves as an intermediary for the impact of the hammer 14 on the tool 3. A damping of the impact by the striker 15 is not desirable.

Fig. 2 zeigt eine beispielhafte Ausgestaltung des Döppers 15. Der Döpper 15 gleitet in einer rohrförmigen Führung 21 auf der Arbeitsachse 7. Die Arbeitsachse 7 wird durch die zylindrische Innenfläche 22 der Führung 21 vorgegeben. Die Innenfläche 22 ist koaxial zu der Arbeitsachse 7 angeordnet. Der Döpper 15 hat eine zylindrische Mantelfläche 23, welche an der Innenfläche 22 anliegt. Die Mantelfläche 23 definiert typischerweise den größten Durchmesser des Döppers 15. Zudem definiert die Mantelfläche 23 eine Längsachse oder Döpperachse 24 des Döppers 15. Die Döpperachse 24 entspricht der Symmetrieachse der Mantelfläche 23. Aufgrund der Führung 21 des Döppers 15 über die führende Mantelfläche 23 liegt die Döpperachse 24 auf der Arbeitsachse 7. 2 shows an exemplary embodiment of the die 15. The die 15 slides in a tubular guide 21 on the working axis 7. The working axis 7 is defined by the cylindrical inner surface 22 of the guide 21 . The inner surface 22 is arranged coaxially to the working axis 7 . The die 15 has a cylindrical lateral surface 23 which bears against the inner surface 22 . The lateral surface 23 typically defines the largest diameter of the die 15. In addition, the lateral surface 23 defines a longitudinal axis or die axis 24 of the die 15. The die axis 24 corresponds to the axis of symmetry of the die Lateral surface 23. Due to the guidance 21 of the die 15 via the leading lateral surface 23 , the die axis 24 lies on the working axis 7.

Der Döpper 15 hat eine Schlagfläche 25, welche in Richtung zu dem Schläger 14 weist. Der Schläger 14 schlägt auf die Schlagfläche 25 auf. Der Flächeninhalt der Schlagfläche 25 ist typischerweise geringer als der Flächeninhalt eines Querschnitts im Bereich der führenden Mantelfläche 23. Die Schlagfläche 25 ist vorzugsweise rotationssymmetrisch zu der Döpperachse 24. Der Schläger 14 schlägt somit mittig auf die Schlagfläche 25, wodurch eine effizientere Energieübertragung gewährleistet ist. Die Schlagfläche 25 kann eben ausgebildet sein, bevorzugt ist eine ballige Ausgestaltung. An die Schlagfläche 25 schließt sich in der dargestellten Ausführungsform ein zylindrischer Abschnitt an, dessen Durchmesser dem Durchmesser der Schlagfläche 25 entspricht.The striker 15 has a striking surface 25 which points in the direction of the racquet 14 . The racquet 14 hits the striking surface 25 . The surface area of the striking surface 25 is typically less than the surface area of a cross section in the area of the leading lateral surface 23. The striking surface 25 is preferably rotationally symmetrical to the die axis 24. The hammer 14 thus strikes the striking surface 25 in the middle , which ensures more efficient energy transfer. The striking surface 25 can be of planar design; a crowned design is preferred. In the illustrated embodiment, the striking surface 25 is followed by a cylindrical section whose diameter corresponds to the diameter of the striking surface 25 .

Der Döpper 15 hat eine Stoßfläche 26, welche in Richtung zu dem Werkzeug 3 zeigt, d.h. in Schlagrichtung 5 und abgewandt von dem Schläger 14 ist. Der Döpper 15 liegt mit der Stoßfläche 26 an dem Werkzeug 3 an oder schlägt mit der Stoßfläche 26 auf das Werkzeug 3 auf. Der Flächeninhalt der Stoßfläche 26 ist typischerweise geringer als der Flächeninhalt eines Querschnitts im Bereich der führenden Mantelfläche 23. Die Schlagfläche 25 ist rotationssymmetrisch zu der Döpperachse 24. Eine Stoßübertragung von dem Döpper 15 auf das Werkzeug 3 erfolgt mittig von der Stoßfläche 26. Die Stoßfläche 26 kann eben oder ballig ausgebildet sein. An die Stoßfläche 26 schließt sich in der dargestellten Ausführungsform ein zylindrischer Abschnitt 27 an, dessen Durchmesser dem Durchmesser der Stoßfläche 26 entspricht.The die 15 has an impact surface 26 which points in the direction of the tool 3 , ie in the direction of impact 5 and is averted from the hammer 14 . The striker 15 bears against the tool 3 with the abutting surface 26 or hits the tool 3 with the abutting surface 26 . The surface area of impact surface 26 is typically less than the surface area of a cross-section in the area of leading lateral surface 23. Impact surface 25 is rotationally symmetrical to die axis 24. Impact transmission from die 15 to tool 3 takes place centrally from impact surface 26. Impact surface 26 can be flat or crowned. In the illustrated embodiment, the abutment surface 26 is adjoined by a cylindrical section 27 whose diameter corresponds to the diameter of the abutment surface 26 .

Der Döpper 15 liegt in der Arbeitsstellung an dem Anschlag 20 an. Der Anschlag 20 kann beispielsweise als Ring ausgebildet sein. Der Ring hat einen Innendurchmesser, der etwas größer als der Durchmesser der Schlagfläche 25 ist. Der Döpper 15 weist eine (Prellschlag-) Fläche 28 auf. Die Prellschlagfläche 28 hat vorzugsweise eine konische Gestalt. Im Bereich der Prellschlagfläche 28 erhöht sich der Durchmesser des Döppers 15 gleichmäßig entlang der Döpperachse 24 von dem geringeren Durchmesser der Schlagfläche 25 auf den Durchmesser der führenden Mantelfläche 23. Die Prellschlagfläche 28 ist rotationssymmetrisch zu der Döpperachse 24. Eine Neigung der Prellschlagfläche 28 gegenüber der Döpperachse 24 und damit auch gegenüber der Arbeitsachse 7 ist vorzugsweise längs der Döpperachse 24 konstant. Der Anschlag 20 kann eine der Prellschlagfläche 28 zugewandte ebenfalls konische Fläche aufweisen. Der Anschlag 20 kann in dem Maschinengehäuse 10 über ein Dämpfelement 29, z.B. einen elastischen O-Ring, abgestützt sein.The snap die 15 rests against the stop 20 in the working position. The stop 20 can be designed as a ring, for example. The ring has an inside diameter that is slightly larger than the diameter of the face 25 . The snap die 15 has a (rebound impact) surface 28 . The impact surface 28 preferably has a conical shape. In the area of the bounce face 28 , the diameter of the die 15 increases uniformly along the die axis 24 from the smaller diameter of the striking face 25 to the diameter of the leading lateral surface 23. The bounce face 28 is rotationally symmetrical to the die axis 24. An inclination of the bounce face 28 relative to the die axis 24 and thus also in relation to the working axis 7 is preferably constant along the die axis 24 . The stop 20 can also have a conical surface facing the rebound impact surface 28 . The stop 20 can be supported in the machine housing 10 via a damping element 29, for example an elastic O-ring.

Der Döpper 15 bewegt sich im meißelnden Betrieb nur geringfügig aus seiner Arbeitsstellung. Nach einem Schlag des Schlägers 14 auf den Döpper 15, bewegt sich der Döpper 15 maximal soweit wie sich das Werkzeug 3 aus dem Werkzeughalter 2 herausbewegt. Aufgrund des Anpressdrucks des Anwenders wird das Werkzeug 3 wieder in die Werkzeugaufnahme hineingeschoben soweit, bis der Döpper 15 an dem Anschlag 20 anliegt.During chiseling operation, the snap die 15 moves only slightly out of its working position. After the beater 14 hits the die 15, the die 15 moves as far as the tool 3 moves out of the tool holder 2 at most. Due to the contact pressure exerted by the user, the tool 3 is pushed back into the tool holder until the snap die 15 rests against the stop 20 .

Fehlt ein Werkzeug 3 oder falls das Werkzeug 3 nicht angedrückt ist, bewegt sich der Döpper 15 deutlich aus der Arbeitsstellung. Ein (Leerschlag-) Fänger 30 stoppt den Döpper 15 in Schlagrichtung 5. Der Döpper 15 schlägt mit einer Stirnfläche 31 auf den Fänger 30 auf. Der Döpper 15 befindet sich dann in seiner in Schlagrichtung 5 am weitest vorgerückten Position. Der Döpper 15 wird etwas gegenüber der Führung 21 verkippt, wenn der Döpper 15 an den Leerschlag-Fänger 30 anschlägt, d.h. die Döpperachse 24 wird gegenüber der Arbeitsachse 7 verkippt. Das Verkippen bewirkt ein Verklemmen des Döppers 15 in der Führung 21, wodurch Bewegungsenergie des Döppers 15 abgebaut wird und der Döpper 15 vorzugsweise zum Stehen kommt. Das Verkippen wird durch eine spezielle Asymmetrie der Stirnfläche 31 des Döppers 15 erreicht.If a tool 3 is missing or if the tool 3 is not pressed, the die 15 moves clearly out of the working position. A (blank strike) catcher 30 stops the striker 15 in the direction of impact 5. The striker 15 strikes the catcher 30 with an end face 31 . The snap die 15 is then in its most advanced position in the direction of impact 5 . The die 15 is tilted somewhat in relation to the guide 21 when the die 15 hits the blank strike catcher 30 , ie the die axis 24 is tilted in relation to the working axis 7 . The tilting causes the die 15 to jam in the guide 21, as a result of which kinetic energy of the die 15 is reduced and the die 15 preferably comes to a standstill. The tilting is achieved by a special asymmetry of the end face 31 of the snap die 15 .

Die Stirnfläche 31 ist in Schlagrichtung 5 weisend und gegenüber der Döpperachse 24 geneigt. Die Schlagfläche 25 verbindet die Mantelfläche 23 mit der Stoßfläche 26. Im Bereich der Stirnfläche 31 reduziert sich der Durchmesser des Döppers 15 von dem maximalen Durchmesser der führenden Mantelfläche 23 auf den Durchmesser der Stoßfläche 26. Die Besonderheit der Stirnfläche 31 ist ihre Unterteilung in Umfangsrichtung 32 in ein erstes Segment 33 und ein zweites Segment 34. In der beispielhaften Ausführung können beide Segmente 33, 34 konusförmig sein. Das erste Segment 33 ist gegenüber dem zweiten Segment 34 in Schlagrichtung 5 versetzt. Die beiden Segmente 33, 34 sind gegenüber der Döpperachse 24 und Arbeitsachse 7 geneigt. Der Versatz zeigt sich darin, dass für einen Ausschnitt der Stirnfläche 31 mit konstanten radialen Abstand zu der Arbeitsachse 7, der Anteil des Ausschnitts zugehörig zu dem ersten Segment 33 näher an der Stoßfläche 26 ist, als der Anteil des Ausschnitts zugehörig zu dem zweiten Segment 34. Das erste Segment 33 stößt somit in Schlagrichtung 5 zuerst an. In einer beispielhaften Ausführung liegt ein Anteil des ersten Segments 33 im Bereich von 200 Grad bis 270 Grad.The end face 31 points in the direction of impact 5 and is inclined relative to the die axis 24 . The impact surface 25 connects the lateral surface 23 with the impact surface 26. In the area of the end face 31 , the diameter of the die 15 reduces from the maximum diameter of the leading lateral surface 23 to the diameter of the impact surface 26. The special feature of the end face 31 is its subdivision in the circumferential direction 32 into a first segment 33 and a second segment 34. In the exemplary embodiment, both segments 33, 34 can be conical. The first segment 33 is offset in the direction of impact 5 in relation to the second segment 34 . The two segments 33, 34 are inclined relative to the die axis 24 and the working axis 7 . The offset is reflected in the fact that for a section of the end face 31 at a constant radial distance from the working axis 7, the portion of the section associated with the first segment 33 is closer to the abutment surface 26 than the portion of the section associated with the second segment 34 The first segment 33 thus strikes first in the direction of impact 5 . In an example implementation, a portion of the first segment 33 ranges from 200 degrees to 270 degrees.

Das zweite Segment 34 ist vorzugsweise konusförmig. Eine Achse des vollständigen Konus, welcher das zweite Segment 34 ausbildet, fällt vorzugsweise mit der Döpperachse 24 zusammen. Das erste Segment 33 kann ebenfalls konusförmig ausgebildet sein. Eine entsprechende Achse fällt nicht mit der Döpperachse 24 zusammen. Die Achse kann zu der Döpperachse 24 parallel versetzt oder gekippt sein. In jedem Querschnitt senkrecht zu der Arbeitsachse 7 ist ein Krümmungsradius r1 des ersten Segments 33 größer als der Krümmungsradius r2 des zweiten Segments. Das flachere erste Segment 33 kann einen größeren Anteil an dem Umfang einnehmen als das steilere zweite Segment 34. The second segment 34 is preferably cone-shaped. An axis of the full cone forming the second segment 34 preferably coincides with the die axis 24 . The first segment 33 can also be cone-shaped. One corresponding axis does not coincide with the die axis 24 . The axis can be offset parallel to the die axis 24 or canted. In each cross section perpendicular to the working axis 7 , a radius of curvature r1 of the first segment 33 is larger than the radius of curvature r2 of the second segment. The flatter first segment 33 can take up a larger proportion of the circumference than the steeper second segment 34.

Der Leerschlag-Fänger 30 ist beispielsweise durch eine konische Verengung der Führung 21 ausgebildet. Die Verengung hat einen Innendurchmesser, welcher größer als der Durchmesser der Stoßfläche 26 des Döppers 15 aber geringer als der Durchmesser der Mantelfläche 23 des Döppers 15 ist. Die Verengung hat eine konische Innenfläche 37, welche in Richtung zu dem Döpper 15 weist. Die konische Innenfläche 37 ist vorzugsweise rotationssymmetrisch zu der Arbeitsachse 7. The blank firing catcher 30 is formed, for example, by a conical narrowing of the guide 21 . The constriction has an inner diameter which is larger than the diameter of the impact surface 26 of the die 15 but less than the diameter of the lateral surface 23 of the die 15 . The constriction has a conical inner surface 37 which faces towards the die 15 . The conical inner surface 37 is preferably rotationally symmetrical to the working axis 7.

Das vordere, erste Segment 34 bewirkt eine größere radiale Kraftkomponente verglichen zu dem flachen Segment 33. Hierdurch wird Döpper 15 verkippt oder wird verbogen. Beide Effekte führen zu einem effizienten Abbremsen des Döppers 15. Dies tritt auch ein, wenn die Führung 21 des Döppers 15 parallel zu der Arbeitsachse 7 aufgrund von Verschleiß bereits ein größeres Spiel aufweist.The front, first segment 34 causes a larger radial force component compared to the flat segment 33. As a result, die 15 is tilted or bent. Both effects lead to efficient braking of the die 15. This also occurs when the guide 21 of the die 15 parallel to the working axis 7 already has greater play due to wear.

Die Führung 21 kann in dem Maschinengehäuse 10 starr verankert sein. Die beispielhafte Führung 21 ist in Schlagrichtung 5 gedämpft aufgehängt. Beispielsweise kann die Führung 21 in einem Gleitlager 38 liegen. Ein Dämpfelement 39, z.B. ein Elastomer, ist zwischen einem gehäusefesten Anschlag 40 und einer Nase 41 eingespannt. Der Anschlag 40 ist in Schlagrichtung 5 von der Nase 41 angeordnet.The guide 21 can be rigidly anchored in the machine housing 10 . The exemplary guide 21 is suspended in a damped manner in the impact direction 5 . For example, the guide 21 can be located in a slide bearing 38 . A damping element 39 , for example an elastomer, is clamped between a stop 40 fixed to the housing and a nose 41 . The stop 40 is arranged by the nose 41 in the impact direction 5 .

In einer Ausgestaltung kann das erste Segment 33 durch eine ebene oder nahezu ebene Abschrägung gebildet sein. Ein Krümmungsradius r1 des ersten Segments 33 ist entsprechend sehr groß. Das erste Segment 33 hat in dieser Ausführung einen geringeren Anteil an dem Umfang, beispielsweise zwischen 30 Grad und 45 Grad.In one configuration, the first segment 33 can be formed by a flat or almost flat bevel. A radius of curvature r1 of the first segment 33 is correspondingly very large. In this embodiment, the first segment 33 has a smaller proportion of the circumference, for example between 30 degrees and 45 degrees.

Claims (6)

  1. Portable power chiseling tool (1), comprising
    a tool holder (2) for holding a tool (3) on a working axis (7),
    a striking mechanism (4) which has an exciter piston (13), a striker (14), a pneumatic chamber (18) which is closed by the exciter piston (13) and the striker (14) and is provided for coupling a movement of the striker (14) to the exciter piston (13), and an anvil (15) which is arranged in the striking direction (5) downstream of the striker (14) and is provided for transmitting a blow of the striker (14) to the tool (3),
    a guide (21) for the anvil (15) for guiding the anvil (15) on the working axis (7),
    an idle strike catcher (30) for the anvil (15), wherein the catcher (30) has a conical inner surface (37) facing the anvil (15), and wherein the anvil (15) has an end face (31) which faces in the striking direction (5), slopes relative to the working axis (7) and rests against the conical inner surface (37) when the anvil (15) is in its forwardmost position in the striking direction (5),
    characterized in that
    the end face (31) of the anvil (15) has a first segment (33) and a second segment (34) in the circumferential direction (32), wherein the second segment (34) is offset in the striking direction (5) relative to the first segment (33).
  2. Portable power chiseling tool (1) according to Claim 1, characterized in that, in a section perpendicular to the working axis (7), the first segment (33) has a first radius of curvature (r1) and the second segment (34) has a second radius of curvature (r2), and the first radius of curvature (r1) is greater than the second radius of curvature (r2).
  3. Portable power chiseling tool (1) according to Claim 1 or 2, characterized in that the first segment (33) is described by a cone, the axis of which is offset relative to the working axis (7).
  4. Portable power chiseling tool (1) according to Claim 3, characterized in that the second segment (34) is described by a cone, the axis of which is coaxial with the working axis (7).
  5. Portable power chiseling tool (1) according to Claim 5, characterized in that the cone of the first segment (33) is offset relative to the cone of the second segment (34) along the working axis (7).
  6. Portable power chiseling tool (1) according to any one of the preceding claims, characterized in that a slope of the first segment (33) relative to the working axis (7) is the same as a slope of the second segment (34) relative to the working axis (7).
EP19812801.9A 2018-12-21 2019-12-04 Handheld chiselling machine tool Active EP3898117B1 (en)

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JP2014166667A (en) * 2013-02-28 2014-09-11 Hitachi Koki Co Ltd Impact tool
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EP3149395A1 (en) 2014-05-30 2017-04-05 Osram Sylvania Inc. Light control films and lighting devices including same

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US20220063078A1 (en) 2022-03-03
CN113165153B (en) 2024-05-24
CN113165153A (en) 2021-07-23
EP3898117A1 (en) 2021-10-27
US11858104B2 (en) 2024-01-02
EP3670096A1 (en) 2020-06-24
WO2020126499A1 (en) 2020-06-25

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