EP3808506A1 - Machine-outil manuelle - Google Patents

Machine-outil manuelle Download PDF

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Publication number
EP3808506A1
EP3808506A1 EP19203810.7A EP19203810A EP3808506A1 EP 3808506 A1 EP3808506 A1 EP 3808506A1 EP 19203810 A EP19203810 A EP 19203810A EP 3808506 A1 EP3808506 A1 EP 3808506A1
Authority
EP
European Patent Office
Prior art keywords
piston
impact
tool
electric motor
acceleration
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Withdrawn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
EP19203810.7A
Other languages
German (de)
English (en)
Inventor
Dario BRALLA
Albert Binder
Donato Clausi
Michael Wierer
Serhey Khandozhko
Nikolaus Hannoschoeck
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 EP19203810.7A priority Critical patent/EP3808506A1/fr
Priority to PCT/EP2020/078041 priority patent/WO2021073960A1/fr
Priority to US17/760,675 priority patent/US11904448B2/en
Priority to EP20781588.7A priority patent/EP4045231A1/fr
Publication of EP3808506A1 publication Critical patent/EP3808506A1/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Withdrawn legal-status Critical Current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
    • B25D11/06—Means for driving the impulse member
    • B25D11/12—Means for driving the impulse member comprising a crank mechanism
    • B25D11/125—Means for driving the impulse member comprising a crank mechanism with a fluid cushion between the crank drive and the striking body
    • 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
    • B25D2250/00—General details of portable percussive tools; Components used in portable percussive tools
    • B25D2250/091—Electrically-powered tool components
    • B25D2250/095—Electric motors
    • 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
    • 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
    • B25D2250/195—Regulation means
    • B25D2250/201—Regulation means for speed, e.g. drilling or percussion speed
    • 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
    • B25D2250/221—Sensors

Definitions

  • the present invention relates to a chiseling hand machine tool with a pneumatic hammer mechanism.
  • a user activates an electric motor by pressing an electrical system button.
  • the hammer mechanism is activated when the user presses a tool inserted into the handheld power tool against a surface.
  • the pressing force on the tool is therefore necessary to keep the hammer mechanism in action. If the contact pressure is not sufficient at the moment, the hammer mechanism switches itself off. Since a slight contact pressure reactivates the striking mechanism after it has been switched off, this can result in an unfavorable, repetitive switching on and off.
  • the control method according to the invention for a handheld power tool includes the steps of: driving an impact mechanism with an electric motor, an exciter piston of the pneumatic impact mechanism being periodically driven by the electric motor and an impact piston of the impact mechanism being coupled to the exciter piston via a pneumatic chamber.
  • the acceleration of a machine housing is recorded along an impact direction of the impact piston at different phases of the movement of the exciter piston.
  • a speed of an electric motor is regulated as a function of the detected acceleration for the different phases.
  • the handheld power tool recognizes, based on the detected accelerations, whether the user controls the handheld power tool in a stable manner or is overwhelmed.
  • the power output of the handheld power tool is controlled accordingly by means of the speed of the electric motor.
  • One embodiment provides that a measure for a pressing force on a tool of the handheld power tool is estimated based on the acceleration and the phase and the rotational speed is regulated based on the estimated pressing force.
  • the handheld power tool has a handle, a machine housing, a tool holder in which a tool is guided along a working axis, and an electric motor for driving an impact mechanism.
  • the pneumatic hammer mechanism has an exciter piston coupled to the electric motor, a percussion piston and a pneumatic chamber coupling the exciter piston to the percussion piston.
  • An acceleration sensor is used to detect an acceleration along a working axis of the machine housing.
  • a sensor is used to detect a phase of the exciter piston.
  • An evaluation unit is used to determine a contact pressure on the tool based on the recorded phase and the recorded acceleration a.
  • a control unit is used to set a speed of the electric motor, the control unit setting a speed in response to a specific contact force.
  • Fig. 1 shows schematically a rotary hammer 1 as an example of a hand-held hand-held power tool.
  • the exemplary rotary hammer 1 has a tool holder 2 in which a tool 3 can be inserted and locked.
  • the tool 3 is, for example, a drill, a chisel, etc.
  • the embodiment shown by way of example rotates the tool holder 2 about a working axis 4 and at the same time exerts periodic blows on the tool along the working axis 4 .
  • the handheld power tool 1 can have a mode selector switch 5 which enables the user to selectively activate and deactivate the rotary movement and selectively the beating operation.
  • the handheld power tool 1 has a handle 6.
  • the user can hold and guide the handheld power tool 1 with the handle 6 during operation.
  • the operating button 7 is preferably attached to the handle 6 in such a way that the user can actuate the operating button 7 with the hand gripping the handle 6.
  • the handle 6 can be decoupled from a machine housing 8 via damping elements.
  • the handheld power tool 1 is switched on and off by the operating button 7.
  • the operating button 7 is arranged in the handle 6 . The user can actuate the operating button 7 preferably with the hand holding the handle 6.
  • the handheld power tool 1 has a rotary drive 9 which is coupled to the tool holder 2.
  • the rotary drive 9 can have, among other things, a step-down gear 10, a slip clutch 11 .
  • An output shaft 12 of the rotary drive 9 is connected to the tool holder 2 .
  • the rotary drive 9 is coupled to an electric motor 13.
  • the user can switch the electric motor 13 on and off by pressing the operating button 7 , the operating button 7 correspondingly controlling a power supply to the electric motor 13.
  • a speed of the electric motor 13 can be set via the operating button 7 .
  • the hand-held power tool 1 has a pneumatic hammer mechanism 14.
  • the pneumatic hammer mechanism 14 has an exciter piston 15 and an impact piston 16.
  • the exciter piston 15 is permanently coupled to the electric motor 13. Since the exciter piston 15 is permanently coupled to the electric motor 13 , the exciter piston 15 moves as soon as the electric motor 13 rotates, ie when the user presses the operating button 7 .
  • the ratio of the speed of the electric motor 13 to the periodicity of the movement of the exciter piston 15 is predetermined by the gear components in the drive train between the electric motor 13 and the exciter piston 15.
  • Exemplary transmission components are an eccentric wheel 17 and a connecting rod 18, which transform the rotational movement of the electric motor 13 into a translational movement on the working axis 4 .
  • the exciter piston 15 and the percussion piston 16 close a pneumatic chamber 19 between one another.
  • a radial closure of the pneumatic chamber 19 is provided by a guide tube 20 which at the same time guides the exciter piston 15 and the percussion piston.
  • the percussion piston can be made hollow and the exciter piston 15 is guided in the percussion piston or vice versa.
  • the air enclosed in the pneumatic chamber 19 is compressed and decompressed by the exciter piston 15.
  • the pressure changes couple the hammer piston to the movement of the exciter piston 15 , the pneumatic chamber 19 behaves like a spring, hence the name air spring.
  • the exciter piston 15 and the percussion piston 16 can be fully cylindrical.
  • the exciter piston 15 can be cup-shaped and the percussion piston 16 is guided in the exciter piston 15.
  • the exciter piston 15 can analogously be guided in the percussion piston 16.
  • the percussion piston 16 can strike the tool 3 directly or indirectly via a striker 21 on the tool.
  • the user exerts a force on the handle 6 in the striking direction 22 in order to press the tool 3 against the wall.
  • the tool 3 can be moved in the tool holder 2 along the striking direction 22 .
  • the tool 3 is shifted against the striking direction 22 into the tool holder 2 and in the process shifts the anvil 21 until it comes to rest against a stop.
  • This position of the striker 21 is referred to below as the working position.
  • the percussion piston 16 strikes the anvil 21 in its working position.
  • the striker 21 in the working position defines the running distance and running time which the percussion piston 16 covers between two strokes.
  • the position in which the striker strikes the striker 21 in the working position is referred to below as the striking point.
  • the pressing force of the user must be sufficient so that the anvil 21 returns to the working position before each next stroke. If the user does not exert any or too little pressing force on the tool 3 , the anvil 21 is not pushed back into the working position after an impact. The striker 21 is now in a blank position. In this case, the pneumatic hammer mechanism 14 deactivates itself automatically in order to avoid damage to the hand-held power tool 1 and injuries to the user. It is switched off by venting the pneumatic chamber 19. The percussion piston 16 is no longer coupled to the exciter piston 15, which continues to move, and comes to a standstill.
  • the pneumatic chamber 19 can be ventilated through ventilation openings in the guide tube 20 .
  • the ventilation openings can be opened or closed, for example, by a path-controlled valve.
  • a path-controlled valve is based on a lateral surface of the percussion piston 16, which, depending on the position, overlaps or does not overlap with the ventilation openings.
  • the ventilation openings are closed when the percussion piston 16 is in front of the percussion point in the direction of impact.
  • the pneumatic chamber 19 is active and the percussion piston 16 is coupled to the exciter piston 15. If the percussion piston 16 exceeds the percussion point in the direction of impact, the ventilation openings are open.
  • the pneumatic chamber 19 is ventilated and thus deactivated.
  • the air moved by the exciter piston 15 can pass through the ventilation openings flow in and out.
  • the pneumatic chamber 19 can also be ventilated using other controlled valves.
  • the ventilation can also take place directly or indirectly through the anvil 21 .
  • the striking mechanism 14 is activated again when the user presses the tool 3 against the substrate.
  • the ventilation openings 23 are closed and the percussion piston 16 is coupled to the exciter piston 15 again.
  • the percussion piston 16 strikes the weakly pressed striker 21 , the percussion piston 16 can slide beyond the point of impact.
  • the striking mechanism 14 deactivates itself again. The user experiences difficulties in gaining control of the handheld power tool 1 .
  • the handheld power tool 1 has a sensor system 24 for detecting the contact pressure of the user.
  • the sensor system 24 is based on an acceleration sensor 25 for detecting an acceleration of the machine housing 8.
  • the acceleration sensor 25 is arranged in the machine housing 8 .
  • the arrangement is such that the acceleration sensor 25 can detect accelerations occurring in the hammer mechanism 14, preferably in an undamped manner.
  • the acceleration sensor 25 is arranged, for example, on the hammer mechanism housing 20, for example the guide tube 20 or a component rigidly connected to the guide tube 20.
  • the impact mechanism housing 20 is accelerated as a function of the movement of impact piston 16, anvil 21 and tool 3, the type of tool 3, the substrate to be processed and on the behavior of the user, including the contact pressure exerted by the user.
  • FIGS. 2, 3 and 4 show the course of the acceleration a as a function of time.
  • the amplitude varies from beat to beat.
  • this is to be expected due to the increasingly degraded subsoil and its inhomogeneities, and a slightly changed behavior of the user also contributes to this.
  • the short-term and very high accelerations can only be recorded with a large tolerance, the accelerations are in the range of 10 times the acceleration due to gravity (dashed line). The amplitude is therefore not suitable for reliably determining the contact pressure.
  • the behavior of the acceleration at the time of the bounce 26 of the striker 21 proves to be a good indication of the contact pressure.
  • the point in time and the duration until the bouncing blow subsides, ie the striker 21 remains in its working position depends on the contact pressure.
  • the influence of the ground and the tool on the time and duration of the bounce shows a different behavior than their influence on the amplitude. This enables the different influences to be differentiated and the contact pressure to be estimated.
  • the acceleration curves specific to the handheld power tool 1 and parameters are stored in a table in a parameterized manner.
  • the table can be stored in a memory 27 in the sensor system 24.
  • the contact pressure is based on the table and a currently recorded acceleration curve can be determined.
  • the acceleration curve is parameterized. The greatest correspondence to the parameters obtained is determined in the table and the associated contact pressure is output.
  • the sensor system 24 can also contain a sensor 28 for detecting a phase of the exciter piston 15.
  • the strictly periodic movement of the exciter piston 15 dominates the timing of the movement of the percussion piston 16 and the anvil 21.
  • the percussion mechanism 14 has a compression phase 29 when the exciter piston 15 and percussion piston 16 compress the pneumatic chamber 19 at the smallest distance from one another. At this point in time, the percussion piston 16 has the greatest reaction on the exciter piston 15 and thus the percussion mechanism housing 20 . Outside of this compression phase, the percussion piston 16 should exert almost no force on the percussion mechanism housing 20 under optimal operating conditions.
  • the other peaks of the acceleration are essentially caused by the kickback of the striker 21 or the impact of the percussion piston 16 in damping elements.
  • the evaluation of the acceleration a is preferably based on the peaks outside the compression phase.
  • the tips can advantageously be assigned to the different phases by separately determining the phase of the exciter piston 15 or the tips outside the compression phase can be selected for the evaluation of the contact pressure.
  • the knowledge of the current phase is important for the exact determination of the point in time when a peak, flank or other characteristic of the acceleration a occurs.
  • a zero point of the time may for example be based on a certain phase 15 of the hammer piston, for example, the phase of the position of the hammer piston remote from the tool 15 from the tool 3.
  • a 3 Evaluation unit 30 for determining the contact pressure can contain a microprocessor or some other data processing device.
  • the phase of the exciter piston 15 can take place by evaluating the acceleration over time. However, several cycles and computing power are required for this.
  • a sensor 28 can determine the phase of the exciter piston 15.
  • the sensor 28 can be integrated, for example, on the exciter piston 15, on the transmission 10 or in the electric motor 13 .
  • the sensor 28 is, for example, an angle sensor, optical sensor, electrical sensor, etc.
  • the motor controller or similar control unit 31 of the handheld power tool 1 reduces the speed of the electric motor 13 if the estimated contact force is less than a setpoint value.
  • the speed can be determined depending on the contact pressure. For example, a table is stored in the motor controller 31 which assigns a speed to a contact force. The assignment can also be stored in the sensor system 24. A reduction in the speed results in a lower impact force of the striking mechanism 14 and can be kept in operation with a lower contact pressure.
EP19203810.7A 2019-10-17 2019-10-17 Machine-outil manuelle Withdrawn EP3808506A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19203810.7A EP3808506A1 (fr) 2019-10-17 2019-10-17 Machine-outil manuelle
PCT/EP2020/078041 WO2021073960A1 (fr) 2019-10-17 2020-10-07 Outil électrique portatif
US17/760,675 US11904448B2 (en) 2019-10-17 2020-10-07 Hand-held power tool
EP20781588.7A EP4045231A1 (fr) 2019-10-17 2020-10-07 Outil électrique portatif

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19203810.7A EP3808506A1 (fr) 2019-10-17 2019-10-17 Machine-outil manuelle

Publications (1)

Publication Number Publication Date
EP3808506A1 true EP3808506A1 (fr) 2021-04-21

Family

ID=68281306

Family Applications (2)

Application Number Title Priority Date Filing Date
EP19203810.7A Withdrawn EP3808506A1 (fr) 2019-10-17 2019-10-17 Machine-outil manuelle
EP20781588.7A Pending EP4045231A1 (fr) 2019-10-17 2020-10-07 Outil électrique portatif

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP20781588.7A Pending EP4045231A1 (fr) 2019-10-17 2020-10-07 Outil électrique portatif

Country Status (3)

Country Link
US (1) US11904448B2 (fr)
EP (2) EP3808506A1 (fr)
WO (1) WO2021073960A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1502710A2 (fr) * 2003-07-31 2005-02-02 Makita Corporation Outil électrique
US20100193205A1 (en) * 2009-01-30 2010-08-05 Hilti Aktiengesellschaft Control method and hand-held power tool
DE102009045758A1 (de) * 2009-10-16 2011-04-21 Robert Bosch Gmbh Handwerkzeug mit einer Werkstofferfassungsvorrichtung

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE527083T1 (de) * 2009-01-30 2011-10-15 Hilti Ag Pneumatisches schlagwerk
DE202011110069U1 (de) 2011-12-21 2013-02-08 Robert Bosch Gmbh Handwerkzeugmaschine
DE102012005803A1 (de) 2012-03-21 2013-09-26 Wacker Neuson Produktion GmbH & Co. KG Bohr-und/oder Schlaghammer mit belastungsabhängiger Anpassung der Schlagzahl
DE102012208902A1 (de) 2012-05-25 2013-11-28 Robert Bosch Gmbh Schlagwerkeinheit
DE102012208855A1 (de) 2012-05-25 2013-11-28 Robert Bosch Gmbh Handwerkzeugmaschine
EP3028820A1 (fr) * 2014-12-03 2016-06-08 HILTI Aktiengesellschaft Machine-outils portative et procédé de commande associé

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1502710A2 (fr) * 2003-07-31 2005-02-02 Makita Corporation Outil électrique
US20100193205A1 (en) * 2009-01-30 2010-08-05 Hilti Aktiengesellschaft Control method and hand-held power tool
DE102009045758A1 (de) * 2009-10-16 2011-04-21 Robert Bosch Gmbh Handwerkzeug mit einer Werkstofferfassungsvorrichtung

Also Published As

Publication number Publication date
WO2021073960A1 (fr) 2021-04-22
US20230021949A1 (en) 2023-01-26
US11904448B2 (en) 2024-02-20
EP4045231A1 (fr) 2022-08-24

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