EP3281747A1 - Machine-outil portative - Google Patents

Machine-outil portative Download PDF

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Publication number
EP3281747A1
EP3281747A1 EP16183369.4A EP16183369A EP3281747A1 EP 3281747 A1 EP3281747 A1 EP 3281747A1 EP 16183369 A EP16183369 A EP 16183369A EP 3281747 A1 EP3281747 A1 EP 3281747A1
Authority
EP
European Patent Office
Prior art keywords
guide tube
cap
hand tool
tool according
compensation opening
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.)
Withdrawn
Application number
EP16183369.4A
Other languages
German (de)
English (en)
Inventor
Stefan Hammerstingl
Eduard Pfeiffer
Matthias Doberenz
Pierre Pallmer
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
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hilti AG filed Critical Hilti AG
Priority to EP16183369.4A priority Critical patent/EP3281747A1/fr
Priority to US16/324,233 priority patent/US11123853B2/en
Priority to EP17745354.5A priority patent/EP3496901B1/fr
Priority to PCT/EP2017/069309 priority patent/WO2018029025A1/fr
Publication of EP3281747A1 publication Critical patent/EP3281747A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • 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
    • B25D16/00—Portable percussive machines with superimposed rotation, the rotational movement of the output shaft of a motor being modified to generate axial impacts on the tool bit
    • 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
    • B25D2217/0019—Guide-sleeves
    • 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
    • B25D2250/035—Bleeding holes, e.g. in piston guide-sleeves

Definitions

  • the present invention relates to a hand tool with an electro-pneumatic impact mechanism.
  • a hammer drill with a pneumatic impact mechanism is off EP 0 759 341 A2 known.
  • the striking mechanism has a guide tube in which a motor-driven exciter piston and a racket complete a pneumatic chamber.
  • the racket follows coupled by the pneumatic chamber of movement of the pathogen.
  • the guide tube is provided with several openings for venting the pneumatic chamber. One opening is used to compensate for losses of the pneumatic chamber, other openings are used for automatic shutdown of the percussion in case of empty space.
  • the portable power tool has a tool holder for holding a tool and a pneumatic percussion mechanism for periodically generating impacts on the tool holder held in the tool holder.
  • the percussion mechanism includes a guide tube, an exciter piston, a racket, a pneumatic chamber enclosed by the exciter piston and the racket in the guide tube, and a compensation opening in the guide tube for ventilating the pneumatic chamber.
  • a cap roofs the compensation opening on an outside of the guide tube roofed. The cap is open in a direction of the guide tube mainly tangential opening direction.
  • the cap directs an airflow from the pneumatic chamber in a defined manner in a direction substantially parallel to the guide tube.
  • the guide tube is surrounded by other components of the power tool, which influence the air flow.
  • a stream of air flowing out of the guide tube in the radial direction strikes one of the assemblies at a short distance from the guide tube.
  • the air flow and entrained by this particle can affect the other assembly, as well as vice versa, the assembly can affect the flow behavior adversely.
  • the air flow along the guide tube can move freely over relatively long distances. A mutual influence is therefore less.
  • the cap is formed by a protuberance of the guide tube.
  • the integrally formed with the guide tube cap has no seams, which lead to an undefined turbulence of the air flow.
  • An underside of the cap facing the pneumatic chamber preferably merges seamlessly into an inner surface of the guide tube.
  • the cap is opened by a puncture, which is predominantly tangential to the guide tube.
  • the predominantly tangential puncture has a maximum inclination of 45 degrees with respect to the guide tube, i. the tangential component of its direction is greater than the radial component.
  • the groove defines the opening direction.
  • the cap has exactly one puncture.
  • a branching of the air flow can lead to turbulence and undefined flow characteristics.
  • One embodiment provides a carrier tube in which the guide tube is arranged.
  • the cap is disposed in a channel formed between the support tube and the guide tube.
  • Fig. 1 shows as an example of a hand-held chiseling machine tool schematically an electric hammer 1.
  • the electric hammer 1 has a tool holder 2, in which a chisel 3 or other tool along a working axis 4 can be used and locked.
  • the electric hammer 1 has a handle 5, which is typically attached to a tool holder 2 remote from the end of a machine housing 6 of the electric hammer 1 .
  • An additional handle can be fastened, for example, near the tool holder 2 .
  • the user can lead and hold the electric hammer 1 with the handles 5 during the chiseling.
  • a power supply can be done via a battery or a power line 7 .
  • the electric hammer 1 has a pneumatic percussion 8 with a racket 9, which exerts periodic blows in the direction of impact 10 on the chisel 3 during operation.
  • the racket 9 is movably guided on the working axis 4 .
  • the racket 9 can strike directly on the chisel 3 in one embodiment.
  • the racket 9 strikes a striker 11, which transfers the impact to the chisel 3 mounted in the tool holder 2 .
  • the striker 11 is arranged in the direction of impact 10 of the racket 9 between the racket 9 and the tool holder 2 .
  • the pneumatic impact mechanism 8 is driven by an electric motor 12 .
  • the electric motor 12 moves a field piston 13 periodically on the working axis 4 back and forth.
  • the excitation piston 13 and the racket 9 close along the working axis 4 from a pneumatic chamber 14 .
  • the pneumatic chamber 14 forms an air spring, which couples the movement of the racket 9 to the movement of the exciter piston 13 .
  • the action of the air spring is based on the compression of the air in the pneumatic chamber 14 and the resulting pressure differential with the environment outside the pneumatic chamber 14.
  • the impact mechanism 8 has a guide tube 15, in which the excitation piston 13 is guided along the working axis 4 .
  • the guide tube 15 has a, preferably cylindrical, inner surface 16, which runs parallel to the working axis 4 .
  • the exciter piston 13 abuts flush against the inner surface 16 .
  • the cross-sectional profile of the exciter piston 13 corresponds to the hollow profile of the guide tube 15.
  • the exciter piston 13 closes the guide tube 15 airtight against the direction of impact 10.
  • the racket 9 is also flush with the inner surface 16 at.
  • the guide tube 15 closes the between the racket 9 and the exciter piston 13 along the working axis 4 completed pneumatic chamber 14 in the radial direction.
  • the stiffness of the air spring is designed for optimal operation of the striking mechanism 8 .
  • the stiffness is due to the amount of air in the pneumatic chamber 14.
  • the pneumatic chamber 14 continuously loses an amount of air due to leakage, especially in the compression of the pneumatic chamber 14 during the tool-facing reversal point of the racket 9 (upper half Fig. 2 ).
  • the loss is compensated by a small radial compensation opening 17 in the guide tube 15 .
  • a diameter of the compensation opening 17 is dimensioned such that, although the losses of the amount of air are balanced, at the same time the effect of the air spring is not affected during a cycle.
  • the flow area is typically less than 5 mm 2 .
  • the compensation opening 17 is covered by a cap 18 on the outer side 19 of the guide tube 15 .
  • the cap 18 abuts directly and preferably seamlessly against the outer side 19 of the guide tube 15 .
  • the cap 18 may have a spherical hollow shape.
  • the illustrated cap 18 is a quarter of a hollow sphere. A radius of curvature of the cap 18 largely corresponds to the radius of the compensation opening 17th
  • the cap 18 is opened by a puncture 20 .
  • An airflow may exit the pneumatic chamber 14 through the equalization port 17 .
  • the air flow is passed through a bottom 21 of the cap 18 until the air flow at the groove 20 can escape into the environment.
  • the underside 21, ie the side of the cap 18 facing the pneumatic chamber 14 preferably changes its inclination relative to the outside 19 from perpendicular in the vicinity of the compensation opening 17 to parallel to the outside 19 at the recess 20. The air flow thus changes 90 degrees diverted.
  • the illustrated recess 20 is exemplary.
  • the recess 20 may pierce the tool-facing surface of the cap 18 as shown, or pierce the tool-facing surface or the circumferentially facing surfaces. Common to these directions is their tangential orientation with respect to the outside 19.
  • the direction of the puncture 20 is shown in the orientation of the underside 21 at the groove 20.
  • the groove 20 is preferably tangential to the outside 19, whereby the air flow is deflected by about 90 degrees. The deflection is at least 45 degrees in other embodiments.
  • the groove 20 is predominantly tangential, a vectorial portion of the radial direction is less than the vectorial portion of the tangential component.
  • the cap 18 is formed by a protuberance of the guide tube 15 .
  • the cylindrical inner surface 16 of the guide tube 15 merges seamlessly into the underside 21 of the cap 18 ; analogously, the outer side 19 merges into an upper side 22 of the cap 18 .
  • the underside 21 of the cap 18 projects radially beyond the cylindrical outer side 19 of the guide tube 15 .
  • the cap 18 preferably covers at least half of the compensation opening 17, preferably the entire compensation opening 17.
  • the guide tube 15 may be arranged coaxially in a carrier tube 23 . Between the guide tube 15 and the support tube 23 , a channel 24 is formed, in which the cap 18 is arranged. The groove 20 faces the channel 24 .
  • the racket 9 closes with its body the compensation opening 17 during its cyclical movement between the compression point (upper half of the image Fig. 2 ) and the impact point (lower half of the picture) Fig. 2 ) Compared with the pneumatic chamber 14.
  • the compensation opening 17 is closed when the pneumatic chamber 14 is highly compressed, in particular at the compression point, and the pneumatic chamber 14 exerts on the racket 9 in the direction of impact 10 accelerating force.
  • the compensation opening 17 is opened when the pressure in the pneumatic chamber 14 is low, in particular when the pressure is below the ambient pressure.
  • the racket 9 does not close the compensation opening 17 when the racket 9 has covered more than one third of the distance from the point of compression to the point of impact.
  • the position of the compensation opening 17 can be optimized with respect to the movement of the exciter piston 13 .
  • the compensation opening 17 is close to the tool-side reversing point of the exciter piston 13 (lower half of the figure Fig. 2 ) arranged.
  • a distance of the compensation opening 17 from the reversal point is typically less than 10% of the stroke of the excitation piston 13.
  • the excitation piston 13 with its body reaches the compensation opening 17 just not to close it.
  • the guide tube 15 preferably has further radial openings 25, which are arranged with respect to the compensation opening 17 in the direction of impact 10 . These further (shut-off) openings 25 serve for a strike shutdown in the case of empty laps.
  • the pneumatic chamber 14 is vented via the shut-off openings 25 when the racket 9 is displaced in the direction of impact 10 beyond the impact position.
  • the shut-off openings 25 are dimensioned such that the periodically moved by the exciter piston 13 amount of air flow through the shut-off openings 25 substantially without resistance or can flow out. Despite the moving exciter piston 13 , the pressure in the pneumatic chamber 14 does not change or does not sufficiently change to move the racket 9 .
  • shut-off openings 25 are many times greater than, usually only, equalization opening 17. Conveniently, several shut-off 25 are arranged at the same height along the working axis 4 to obtain a desired large flow area, which is much larger as the flow cross section of the compensation opening 17 is.
  • the shut-off openings 25 are possible in various designs.
  • the pneumatic chamber 14 overlaps only with the shut-off openings 25 when the racket 9 is displaced in the direction of impact 10 beyond the impact point.
  • the shut-off openings 25 are arranged near the impact point, whereby the racket 9 with its body closes the shut-off openings 25 with respect to the pneumatic chamber 14 until the racket 9 is moved beyond the impact point.
  • the club 9 or the striker 11 actuate a sleeve which release or close the shut-off openings 25 .
  • the position of the shut-off openings 25 can be chosen freely in this case.
  • the excitation piston 13 is connected via a drive train 26 to the electric motor 12 .
  • the powertrain 26 includes a converter 27 which converts the rotational motion of the electric motor 12 into a translational motion.
  • the exemplary illustrated converter 27 is based on an eccentric wheel driven by the electric motor 12 and the connecting rod anchored in the exciter piston 13 .
  • An alternative embodiment uses instead of an eccentric a swash plate to which the connecting rod attacks.
  • the powertrain 26 may further include a reduction gear 29 and protective mechanisms, such as a slip clutch 30 .
  • the mechanical and rigid connection of the excitation piston 13 to the electric motor 12 ensures a synchronous movement of the electric motor 12 and excitation piston 13.
  • the electric motor 12 and the drive train 26 are arranged in the machine housing 6 of the electric hammer 1 .
  • the electric motor 12 is powered by the power supply.
  • the electric motor 12 may be a universal motor, a mechanically commutating electric motor 12, or an electrically commutating electric motor 12 .
  • the user can switch the electric motor 12 on and off with an operating button 31 .
  • the operation button 31 is arranged on or near the handle 5 and can preferably be operated by the hand holding the handle 5 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
EP16183369.4A 2016-08-09 2016-08-09 Machine-outil portative Withdrawn EP3281747A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP16183369.4A EP3281747A1 (fr) 2016-08-09 2016-08-09 Machine-outil portative
US16/324,233 US11123853B2 (en) 2016-08-09 2017-07-31 Hand-held power tool
EP17745354.5A EP3496901B1 (fr) 2016-08-09 2017-07-31 Machine-outil portative
PCT/EP2017/069309 WO2018029025A1 (fr) 2016-08-09 2017-07-31 Machine-outil portative

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP16183369.4A EP3281747A1 (fr) 2016-08-09 2016-08-09 Machine-outil portative

Publications (1)

Publication Number Publication Date
EP3281747A1 true EP3281747A1 (fr) 2018-02-14

Family

ID=56681988

Family Applications (2)

Application Number Title Priority Date Filing Date
EP16183369.4A Withdrawn EP3281747A1 (fr) 2016-08-09 2016-08-09 Machine-outil portative
EP17745354.5A Active EP3496901B1 (fr) 2016-08-09 2017-07-31 Machine-outil portative

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP17745354.5A Active EP3496901B1 (fr) 2016-08-09 2017-07-31 Machine-outil portative

Country Status (3)

Country Link
US (1) US11123853B2 (fr)
EP (2) EP3281747A1 (fr)
WO (1) WO2018029025A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0759341A2 (fr) 1995-08-18 1997-02-26 Makita Corporation Marteau perforateur avec mécanisme de prévention des frappes à vide
EP2514569A1 (fr) * 2011-04-19 2012-10-24 HILTI Aktiengesellschaft Machine-outil manuelle et procédé de fabrication
EP2669060A1 (fr) * 2012-05-29 2013-12-04 HILTI Aktiengesellschaft Machine-outil de burinage

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE637015A (fr) * 1962-09-11
ZA803409B (en) * 1979-06-18 1981-05-27 Kango Electric Hammers Ltd Hammer drill
SE467450B (sv) * 1989-10-28 1992-07-20 Berema Atlas Copco Ab Begraensningsanordning vid handhaallet slagverktyg
DE4239294A1 (de) * 1992-11-23 1994-05-26 Black & Decker Inc Bohrhammer mit pneumatischem Schlagwerk
DE19843642B4 (de) * 1998-09-23 2004-03-25 Wacker Construction Equipment Ag Luftfederschlagwerk mit Rückholluftfeder
DE10121088A1 (de) * 2001-04-28 2002-11-07 Bosch Gmbh Robert Bohr- und/oder Meißelhammer
DE10145464C2 (de) * 2001-09-14 2003-08-28 Wacker Construction Equipment Bohr- und/oder Schlaghammer mit anpressdruckabhängiger Leerlaufsteuerung
US6932166B1 (en) * 2002-12-03 2005-08-23 Paul Kirsch Pneumatic tool
EP1607187B1 (fr) * 2004-06-18 2010-04-28 HILTI Aktiengesellschaft Appareil pour l'amélioration de la réponse en coupure d'un outil électropneumatique à percussion
DE102005028918A1 (de) * 2005-06-22 2006-12-28 Wacker Construction Equipment Ag Bohr- und/oder Schlaghammer mit Leerlaufsteuerung
JP2009539628A (ja) * 2006-06-06 2009-11-19 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング 打撃ピン及び対応配置された拘束装置を備えた打撃機構
DE102009026542A1 (de) * 2009-05-28 2010-12-09 Hilti Aktiengesellschaft Werkzeugmaschine
DE102010029915A1 (de) * 2010-06-10 2011-12-15 Hilti Aktiengesellschaft Werkzeugmaschine und Steuerungsverfahren
DE102012206452A1 (de) * 2012-04-19 2013-10-24 Hilti Aktiengesellschaft Handwerkzeugmaschine und Steuerungsverfahren

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0759341A2 (fr) 1995-08-18 1997-02-26 Makita Corporation Marteau perforateur avec mécanisme de prévention des frappes à vide
EP2514569A1 (fr) * 2011-04-19 2012-10-24 HILTI Aktiengesellschaft Machine-outil manuelle et procédé de fabrication
EP2669060A1 (fr) * 2012-05-29 2013-12-04 HILTI Aktiengesellschaft Machine-outil de burinage

Also Published As

Publication number Publication date
WO2018029025A1 (fr) 2018-02-15
US11123853B2 (en) 2021-09-21
EP3496901A1 (fr) 2019-06-19
EP3496901B1 (fr) 2024-07-10
US20190168369A1 (en) 2019-06-06

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