EP0199883B1 - Motor-driven hand tool - Google Patents

Motor-driven hand tool Download PDF

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Publication number
EP0199883B1
EP0199883B1 EP85810591A EP85810591A EP0199883B1 EP 0199883 B1 EP0199883 B1 EP 0199883B1 EP 85810591 A EP85810591 A EP 85810591A EP 85810591 A EP85810591 A EP 85810591A EP 0199883 B1 EP0199883 B1 EP 0199883B1
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EP
European Patent Office
Prior art keywords
motor
bearing block
crankshaft
gear shaft
housing
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.)
Expired - Lifetime
Application number
EP85810591A
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German (de)
French (fr)
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EP0199883A3 (en
EP0199883A2 (en
Inventor
Werner Klingenbeck
Anton Neumaier
Hans-Jürgen Hoereth
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Hilti AG
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Hilti AG
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Publication date
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Publication of EP0199883A2 publication Critical patent/EP0199883A2/en
Publication of EP0199883A3 publication Critical patent/EP0199883A3/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
    • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
    • B25B23/147—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
    • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for

Definitions

  • the invention relates to a motor-operated hand tool with a housing, a motor arranged therein, a drive shaft set in rotation by the motor and a transmission with a torque measuring device arranged between the motor and the drive shaft.
  • Motor-operated hand tools are used for various purposes, such as drilling, grinding, sawing, milling and the like.
  • the reaction moment that occurs must be applied by the operator. Under normal circumstances this is easily possible. In special situations, such as when the tool suddenly jams or jams, this reaction moment can increase very quickly and very strongly. If the operator is not prepared for this, this can lead to accidents with more or less serious consequences.
  • DE-A-2 442 260 Another solution known from DE-A-2 442 260 consists in providing weakening points on the housing or on the handle of the hand tool, the deformation of which is measured, for example, by means of a strain gauge. It is therefore not the torque that is measured, but rather the resulting deformation of the housing or the handle. The results of such measurements can be falsified, for example, by the operator holding and guiding the hand tool not only by the handles, but by the housing. This method also does not enable the forces and moments that occur to be precisely determined.
  • the motor is movably mounted in the housing and is supported in the housing via at least one support bearing that receives the reaction torque of the electric motor.
  • the support bearing contains a pressure sensor made of electrically conductive plastic material, the electrical resistance of which changes depending on the pressure exerted.
  • the reaction torque occurring at the motor is measured with this solution. Since the required power is mainly achieved in hand tools for weight reasons due to a very high motor speed, the torque that occurs on the motor shaft is usually very small. This means that the reaction forces that occur on the motor are also relatively low. As a result of friction, inertia of the masses to be accelerated and the like, such disturbing influences occur that the reaction torque that actually occurs on the tool cannot be determined exactly at this point.
  • a pressure sensor reacts to the axial force generated by a helical toothing of the motor shaft, which is directly proportional to the transmitted torque.
  • An electrically conductive plastic material is used as the pressure sensor, the resistance of which changes depending on the pressure exerted. Since the axial force on the motor is relatively low, the measuring element must be very sensitive, which has a disadvantageous effect in rough construction site operation.
  • DE-A-2 149 017 shows a transmission with a rotatably mounted rocker arm for receiving an idler gear shaft.
  • the swing arm is supported on the gear unit by spring elements. If the swing arm deflects as a result of the reaction moments that occur, limit switches are actuated, which lead to the drive motor being switched off, provided the complex adjustment work has been carried out correctly and correctly with regard to the forces that occur.
  • the invention has for its object to detect the reaction torque occurring on the tool accurately and without a time delay in a hand tool.
  • this object is achieved in that the torque measuring device engages at least one gear shaft, a gear wheel which is in engagement with the gear shaft with a crankshaft, and a motor pinion which engages around the gear shaft which runs parallel to the gear shaft and is coaxial with the axis of rotation of the gear wheel crankshaft rotatably mounted bearing block, the gear shaft and crankshaft are mounted in the bearing block and the bearing block is supported on the housing via electrical force measuring elements made of piezoceramic.
  • this transmission shaft is located in the "drive chain" of the transmission to the work spindle, the more precisely and quickly the torque occurring on the work spindle can be detected. In principle, it is sufficient to provide a single force measuring element. However, if the hand tool has a possibility of reversing the direction of rotation, two force measuring elements are preferably to be provided, which can be arranged, for example, in pairs opposite one another.
  • the gear shaft mounted in the bearing block is at least in engagement with another shaft via toothings.
  • the Pivot axis of the bearing block coaxial with the axis of rotation of a gear wheel which is in engagement with the gear shaft.
  • the movement of the bearing block thus corresponds in principle to that of the web of a planetary gear.
  • the effective displacement or swivel path in the area of the force measuring elements can be very small and usually only be a few tenths of a millimeter.
  • the force measuring elements are expediently made of piezoceramic for an accurate detection of the forces occurring.
  • an electrical charge is created when deformed by external force. This charge is proportional to the deformation or the force that occurs and can be converted into a voltage by suitable amplifiers.
  • the deformation path of such elements is a few pm.
  • the signal of the force measuring elements can be evaluated differently depending on the demands placed on the ease of use of the hand tool. For example, it is sufficient for certain applications to emit an optical or acoustic signal when a certain value is exceeded.
  • the signal from the force measuring elements is preferably used to generate control functions of the hand tool. In this case, for example, a clutch interrupting the torque transmission or a brake converting the still existing rotational energy of the transmission shafts into heat can be actuated.
  • the hand tool shown in FIGS. 1 and 2 has a housing, generally designated 1, to which a handle 2 is detachably connected.
  • the handle 2 has a push button 3 for switching the hand tool on and off and a feed line 4 for the electrical power supply of the hand tool.
  • a motor generally designated 5
  • a motor pinion 5a meshes with a gear 6.
  • the gearwheel 6 is firmly connected to a crankshaft, denoted overall by 7.
  • the crankshaft 7 is mounted on the one hand in a radial bearing 8 and on the other hand in a bearing plate 5b of the engine 5.
  • the radial bearing 8 is arranged in a bearing block, designated overall by 9, which is pivotably mounted in a bore 1a of the housing by means of an extension 9a.
  • the crankshaft 7 is provided with a toothing 7a which is in engagement with a spur gear 10.
  • the spur gear 10 is fixedly connected to a pinion shaft, designated overall by 11.
  • the pinion shaft 11 is also supported in the bearing block 9 via an angular contact ball bearing 12. Since the bearing block 9 is pivotally mounted about the axis of the crankshaft 7, the spur gear 10 and the toothing 7a remain unchanged in the event of a pivoting movement of the bearing block 9.
  • the pinion shaft 11 carries a bevel pinion 11 a, which is in engagement with a bevel gear 13.
  • the bevel gear 13 is non-rotatably connected to a cylinder 14 and secured against axial displacement by means of a locking ring 15.
  • the cylinder 14 is mounted above the bevel gear 13 in the housing 1 by means of a needle bearing 16.
  • an excitation piston 17 is axially displaceably guided.
  • the excitation piston 17 is connected by means of a connecting rod 18 to a crank pin 7b of the crankshaft 7 and is set in a reciprocating movement when the crankshaft 7 is rotated.
  • a percussion piston 19 is also axially displaceably guided in the cylinder 14.
  • a drill 22 is inserted into a tool holder 21 and is actuated by the percussion piston 19. The rotary movement is transmitted to the drill 22 via the cylinder 14.
  • FIG. 2 shows the projection 9a of the bearing block, which is pivotably mounted in the bore 1a of the housing 1. Since the crankshaft 7 is mounted coaxially in the bearing block 9, the position of the radial bearing 8 is not changed by the pivoting of the bearing block 9.
  • the part of the bearing block 9 which receives the angular contact ball bearing 12 is provided with two opposing support surfaces 9b.
  • Force measuring elements 23 arranged in recesses 1b of the housing 1 are stressed by the reaction forces arising during the torque transmission from the crankshaft 7 to the pinion shaft 11.
  • the signal of the force measuring elements 23 is used to generate control functions of the hand tool and can be used, for example, to switch off the energy supply, to actuate a clutch or brake and the like.
  • the force measuring elements 23 are preferably made of piezoceramic. Such elements generate an electrical charge when subjected to pressure, which can be converted into a voltage. By arranging two opposing force measuring elements 23, the forces occurring in both directions of rotation can be detected if the direction of rotation of the motor 5 is reversed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Drilling And Boring (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)

Description

Die Erfindung betrifft ein motorisch betriebenes Handwerkzeug mit einem Gehäuse, einem darin angeordneten Motor, einer vom Motor in Drehung versetzten Antriebswelle und einem zwischen dem Motor und der Antriebswelle angeordneten Getriebe mit Drehmomentmesseinrichtung.The invention relates to a motor-operated hand tool with a housing, a motor arranged therein, a drive shaft set in rotation by the motor and a transmission with a torque measuring device arranged between the motor and the drive shaft.

Motorisch betriebene Handwerkzeuge werden für unterschiedliche Zwecke, wie Bohren, Schleifen, Sägen, Fräsen und dgl eingesetzt. Beim Arbeiten mit solchen Geräten von Hand muss das auftretende Reaktionsmoment von der Bedienungsperson aufgebracht werden. Unter normalen Umständen ist dies ohne weiteres möglich. In besonderen Situationen, wie beispielsweise bei einem plötzlich auftretenden Klemmen oder Blokkieren des Werkzeuges, kann dieses Reaktionsmoment sehr rasch und sehr stark ansteigen. Ist die Bedienungsperson darauf nicht vorbereitet, so kann dies zu Unfällen mit mehr oder weniger schweren Folgen führen.Motor-operated hand tools are used for various purposes, such as drilling, grinding, sawing, milling and the like. When working with such devices by hand, the reaction moment that occurs must be applied by the operator. Under normal circumstances this is easily possible. In special situations, such as when the tool suddenly jams or jams, this reaction moment can increase very quickly and very strongly. If the operator is not prepared for this, this can lead to accidents with more or less serious consequences.

Um dies zu vermeiden, ist es bekannt, die Handwerkzeuge mit Sicherheitskupplungen zu versehen, welche bei einem vorbestimmten Wert die Drehmomentübertragung vom Motor auf das Werkzeug unterbrechen. Diese bei Ueberlast schaltenden Kupplungen sind meist relativ träge und können Unfälle somit sehr oft nicht wirksam verhüten. Ausserdem sind die meisten Kupplungen auf ein bestimmtes Auslösemoment ausgelegt, das den unterschiedlichen Arbeitsverhältnissen der Werkzeuge nicht angepasst werden kann.In order to avoid this, it is known to provide the hand tools with safety clutches which interrupt the torque transmission from the motor to the tool at a predetermined value. These clutches that switch when overloaded are usually relatively slow and therefore very often cannot effectively prevent accidents. In addition, most couplings are designed for a specific triggering torque that cannot be adapted to the different working conditions of the tools.

Eine weitere aus der DE-A-2 442 260 bekannte Lösung besteht darin, am Gehäuse bzw am Handgriff des Handwerkzeuges Schwächungsstellen vorzusehen, deren Verformung beispielsweise mittels Dehnmessstreifens gemessen wird. Es wird somit nicht das Drehmoment, sondern die sich daraus ergebende Verformung des Gehäuses bzw des Handgriffes gemessen. Die Resultate solcher Messungen können beispielsweise dadurch verfälscht werden, dass die Bedienungsperson das Handwerkzeug nicht nur an den Handgriffen, sondern am Gehäuse hält und führt. Damit ermöglicht auch diese Methode keine genaue Bestimmung der auftretenden Kräfte und Momente.Another solution known from DE-A-2 442 260 consists in providing weakening points on the housing or on the handle of the hand tool, the deformation of which is measured, for example, by means of a strain gauge. It is therefore not the torque that is measured, but rather the resulting deformation of the housing or the handle. The results of such measurements can be falsified, for example, by the operator holding and guiding the hand tool not only by the handles, but by the housing. This method also does not enable the forces and moments that occur to be precisely determined.

Bei einem weiteren aus der GB-A-2 108 272 bekannten Elektrowerkzeug ist der Motor im Gehäuse beweglich gelagert und über wenigstens ein das Reaktionsdrehmoment des Elektromotors aufnehmendes Stützlager im Gehäuse abgestützt. Das Stützlager enthält dabei einen Drucksensor aus elektrisch leitendem Kunststoffmaterial, dessen elektrischer Widerstand sich abhängig vom ausgeübten Druck ändert. Bei dieser Lösung wird somit im Prinzip das am Motor auftretende Reaktionsmoment gemessen. Da bei Handwerkzeugen die erforderliche Leistung hauptsächlich aus Gewichtsgründen aufgrund einer sehr hohen Motordrehzahl erzielt wird, ist das an der Motorwelle auftretende Drehmoment meist sehr klein. Somit sind auch die am Motor auftretenden Reaktionskrafte relativ gering. Infolge Reibung, Massenträgheit der zu beschleunigenden Massen und dgl treten derartige Störeinflüsse auf, dass an dieser Stelle das effektiv am Werkzeug auftretende Reaktionsmoment nicht genau bestimmt werden kann.In a further power tool known from GB-A-2 108 272, the motor is movably mounted in the housing and is supported in the housing via at least one support bearing that receives the reaction torque of the electric motor. The support bearing contains a pressure sensor made of electrically conductive plastic material, the electrical resistance of which changes depending on the pressure exerted. In principle, the reaction torque occurring at the motor is measured with this solution. Since the required power is mainly achieved in hand tools for weight reasons due to a very high motor speed, the torque that occurs on the motor shaft is usually very small. This means that the reaction forces that occur on the motor are also relatively low. As a result of friction, inertia of the masses to be accelerated and the like, such disturbing influences occur that the reaction torque that actually occurs on the tool cannot be determined exactly at this point.

Aus der FR-A-2 517 134 ist ein Elektrowerkzeug mit einer Drehmomentmesseinrichtung bekannt. Dabei reagiert ein Drucksensor auf die durch eine Schrägverzahnung der Motorwelle erzeugte, mit dem übertragenen Drehmoment direkt proportionnale Axialkraft. Als Drucksensor wird ein elektrisch leitendes Kunststoffmaterial verwendet, dessen Widerstand sich abhängig vom ausgeübten Druck ändert. Da die Axialkraft am Motor relativ gering ist, muss das Messglied sehr empfindlich sein, was sich im rauhen Baustellenbetrieb nachteilig auswirkt.From FR-A-2 517 134 an electric tool with a torque measuring device is known. A pressure sensor reacts to the axial force generated by a helical toothing of the motor shaft, which is directly proportional to the transmitted torque. An electrically conductive plastic material is used as the pressure sensor, the resistance of which changes depending on the pressure exerted. Since the axial force on the motor is relatively low, the measuring element must be very sensitive, which has a disadvantageous effect in rough construction site operation.

Die DE-A-2 149 017 zeigt ein Getriebe mit einer drehbar gelagerten Schwinge zur Aufnahme einer Zwischenradwelle. Die Schwinge ist über Federelemente am Getriebegerüst abgestützt. Bei einem Ausschlag der Schwinge infolge der auftretenden Reaktionsmomente werden Endschalter betätigt, die zu einem Abschalten des Antriebsmotors führen, sofern die aufwendigen Einstellarbeiten exakt und hinsichtlich auftretender Kräfte richtig durchgeführt wurden.DE-A-2 149 017 shows a transmission with a rotatably mounted rocker arm for receiving an idler gear shaft. The swing arm is supported on the gear unit by spring elements. If the swing arm deflects as a result of the reaction moments that occur, limit switches are actuated, which lead to the drive motor being switched off, provided the complex adjustment work has been carried out correctly and correctly with regard to the forces that occur.

Der Erfindung liegt die Aufgabe zugrunde, bei einem Handwerkzeug das am Werkzeug auftretende Reaktionsmoment genau und ohne zeitliche Verzögerung zu erfassen.The invention has for its object to detect the reaction torque occurring on the tool accurately and without a time delay in a hand tool.

Gemäss der Erfindung wird diese Aufgabe dadurch gelöst, dass die Drehmomentmesseinrichtung wenigstens eine Getriebewelle, ein mit der Getriebewelle im Eingriff stehendes mit einer kurbelwelle fest verbundenes Zahnrad und einen um die parallel zur Getriebewelle verlaufende sowie koaxial zur Drehachse des Zahnrades stehende mit einem Motorritzel in Eingriff stehende kurbelwelle drehbar gelagerten Lagerbock umfasst, wobei Getriebewelle und kurbelwelle im Lagerbock gelagert sind und der Lagerbock über elektrische Kraftmesselemente aus Piezokeremik am Gehäuse abgestützt ist.According to the invention, this object is achieved in that the torque measuring device engages at least one gear shaft, a gear wheel which is in engagement with the gear shaft with a crankshaft, and a motor pinion which engages around the gear shaft which runs parallel to the gear shaft and is coaxial with the axis of rotation of the gear wheel crankshaft rotatably mounted bearing block, the gear shaft and crankshaft are mounted in the bearing block and the bearing block is supported on the housing via electrical force measuring elements made of piezoceramic.

Je näher sich diese Getriebewelle in der "Antriebskette" des Getriebes an der Arbeitsspindel befindet, desto genauer und rascher kann das an der Arbeitsspindel auftretende Drehmoment erfasst werden. Im Prinzip genügt es, ein einziges Kraftmesselement vorzusehen. Falls das Handwerkzeug jedoch eine Möglichkeit zur Drehrichtungsumkehr aufweist, sind vorzugsweise zwei Kraftmesselemente vorzusehen, die beispielsweise paarweise einander gegenüberliegend angeordnet sein können.The closer this transmission shaft is located in the "drive chain" of the transmission to the work spindle, the more precisely and quickly the torque occurring on the work spindle can be detected. In principle, it is sufficient to provide a single force measuring element. However, if the hand tool has a possibility of reversing the direction of rotation, two force measuring elements are preferably to be provided, which can be arranged, for example, in pairs opposite one another.

Durch die parallel zur Getriebewelle verlaufende Schwenkachse des Lagerbockes wird ein Schiefstellen der Getriebewelle beim Schwenken des Lagerbockes praktisch vermieden.Due to the pivot axis of the pedestal running parallel to the gear shaft, skewing of the gear shaft when pivoting the pedestal is practically avoided.

Die im Lagerbock gelagerte Getriebewelle steht zumindest mit einer weiteren Welle über Verzahnungen im Eingriff. Um durch das Schwenken des Lagerbockes die Eingriffsverhältnisse an den Zahnflanken nicht zu verändern, verläuft die Schwenkachse des Lagerbockes koaxial zur Drehachse eines mit der Getriebewelle im Eingriff stehenden Zahnrades. Die Bewegung des Lagerbockes entspricht somit im Prinzip derjenigen des Steges eines Planetengetriebes. Der effektive Verschiebeweg bzw Schwenkweg im Bereich der Kraftmesselemente kann sehr gering sein und meistens nur einige Zehntelsmillimeter betragen.The gear shaft mounted in the bearing block is at least in engagement with another shaft via toothings. In order not to change the engagement conditions on the tooth flanks by swiveling the pedestal, the Pivot axis of the bearing block coaxial with the axis of rotation of a gear wheel which is in engagement with the gear shaft. The movement of the bearing block thus corresponds in principle to that of the web of a planetary gear. The effective displacement or swivel path in the area of the force measuring elements can be very small and usually only be a few tenths of a millimeter.

Für eine genaue Erfassung der auftretenden Kräfte bestehen die Kraftmesselemente zweckmässigerweise aus Piezokeramik. In solchen aus Piezokeramik bestehenden Kraftmesselementen entsteht bei Verformung durch äussere Krafteinwirkung eine elektrische Ladung. Diese Ladung ist proportional zur Verformung bzw zur auftretenden Kraft und kann durch geeignete Verstärker in eine Spannung umgesetzt werden. Der Verformungsweg solcher Elemente beträgt einige pm.The force measuring elements are expediently made of piezoceramic for an accurate detection of the forces occurring. In such force measuring elements made of piezoceramic, an electrical charge is created when deformed by external force. This charge is proportional to the deformation or the force that occurs and can be converted into a voltage by suitable amplifiers. The deformation path of such elements is a few pm.

Je nach den an den Bedienungskomfort des Handwerkzeuges gestellten Ansprüchen kann das Signal der Kraftmesselemente unterschiedlich ausgewertet werden. So genügt es beispielsweise für gewisse Anwendungen, bei Ueberschreiten eines bestimmten Wertes ein optisches oder akustisches Signal abzugeben. Vorzugsweise dient das Signal der Kraftmesselemente der Erzeugung von Steuerfunktionen des Handwerkzeuges. Dabei kann beispielsweise eine die Drehmomentübertragung unterbrechende Kupplung oder eine die noch vorhandene Rotationsenergie der Getriebswellen in Wärme umwandelnde Bremse betätigt werden.The signal of the force measuring elements can be evaluated differently depending on the demands placed on the ease of use of the hand tool. For example, it is sufficient for certain applications to emit an optical or acoustic signal when a certain value is exceeded. The signal from the force measuring elements is preferably used to generate control functions of the hand tool. In this case, for example, a clutch interrupting the torque transmission or a brake converting the still existing rotational energy of the transmission shafts into heat can be actuated.

Die Erfindung soll nachstehend anhand einer sie beispielsweise wiedergebenden Zeichnung näher erläutert werden. Es zeigen:

  • Fig. 1 ein erfindungsgemässes Handwirkzeug, teilweise aufgeschnitten dargestellt;
  • Fig. 2 einen Querschnitt durch das in Fig. 1 dargestellte Handwerkzeug entlang der Linie 11-11, in vergrössertem Masstab.
The invention will be explained in more detail below with the aid of a drawing, for example. Show it:
  • 1 shows a hand-knitted tool according to the invention, partially cut away;
  • Fig. 2 shows a cross section through the hand tool shown in Fig. 1 along the line 11-11, on an enlarged scale.

Das aus den Fig. 1 und 2 ersichtliche Handwerkzeug weist ein insgesamt mit 1 bezeichnetes Gehäuse auf, mit dem ein Handgriff 2 lösbar verbunden ist. Der Handgriff 2 weist einen Drükker 3 zum Ein- und Ausschalten des Handwerkzeuges sowie eine Zuleitung 4 zur elektrischen Stromversorgung des Handwerkzeuges auf. Im unteren Teil des Gehäuses 1 ist ein insgesamt mit 5 bezeichneter Motor angeordnet. Ein Motorritzel 5a steht mit einem Zahnrad 6 im Eingriff. Das Zahnrad 6 ist mit einer insgesamt mit 7 bezeichneten Kurbelwelle fest verbunden. Die Kurbelwelle 7 ist einerseits in einem Radiallager 8 und andererseits in einem Lagerschild 5b des Motors 5 gelagert. Das Radiallager 8 ist in einem insgesamt mit 9 bezeichneten Lagerbock angeordnet, der mittels eines Ansatzes 9a in einer Bohrung 1a des Gehäuses schwenkbar gelagert ist. Die Kurbelwelle 7 ist mit einer Verzahnung 7a versehen, die mit einem Stirnrad 10 in Eingriff steht. Das Stirnrad 10 ist mit einer insgesamt mit 11 bezeichneten Ritzelwelle fest verbunden. Die Ritzelwelle 11 ist über ein Schrägkugellager 12 ebenfalls im Lagerbock 9 abgestützt. Da der Lagerbock 9 um die Achse der Kurbelwelle 7 schwenkbar gelagert ist, bleiben des Stirnrad 10 und die Verzahnung 7a bei einer allfälligen Schwenkbewegung des Lagerbockes 9 unverändert in Eingriff. Die Ritzelwelle 11 trägt ein Kegelritzel 11a, das mit einem Kegelrad 13 in Eingriff steht. Das Kegelrad 13 ist mit einem Zylinder 14 drehfest verbunden und mittels eines Sicherungsringes 15 gegen axiales Verschieben gesichert. Der Zylinder 14 ist über der Kegelrad 13 mittels eines Nadellagers 16 im Gehäuse 1 gelagert. Im Zylinder 14 ist ein Erregerkolben 17 axial verschiebbar geführt. Der Erregerkolben 17 ist mittels eines Pleuels 18 mit einem Kurbelzapfen 7b der Kurbelwelle 7 verbunden und wird beim Drehen der Kurbelwelle 7 in eine hin- und hergehende Bewegung versetzt. Im Zylinder 14 ist ebenfalls ein Schlagkolben 19 axial verschiebbar geführt. Zwischen dem Erregerkolben 17 und dem Schlagkolben 19 befindet sich ein Luftpolster 20, das zur Uebertragung der Schlagenergie vom Erregerkolben 17 auf den Schlagkolben 19 dient. In einen Werkzeughalter 21 ist ein Bohrer 22 eingesetzt, der vom Schlagkolben 19 beaufschalgt wird. Die Uebertragung der Drehbewegung auf den Bohrer 22 erfolgt über den Zylinder 14.The hand tool shown in FIGS. 1 and 2 has a housing, generally designated 1, to which a handle 2 is detachably connected. The handle 2 has a push button 3 for switching the hand tool on and off and a feed line 4 for the electrical power supply of the hand tool. In the lower part of the housing 1, a motor, generally designated 5, is arranged. A motor pinion 5a meshes with a gear 6. The gearwheel 6 is firmly connected to a crankshaft, denoted overall by 7. The crankshaft 7 is mounted on the one hand in a radial bearing 8 and on the other hand in a bearing plate 5b of the engine 5. The radial bearing 8 is arranged in a bearing block, designated overall by 9, which is pivotably mounted in a bore 1a of the housing by means of an extension 9a. The crankshaft 7 is provided with a toothing 7a which is in engagement with a spur gear 10. The spur gear 10 is fixedly connected to a pinion shaft, designated overall by 11. The pinion shaft 11 is also supported in the bearing block 9 via an angular contact ball bearing 12. Since the bearing block 9 is pivotally mounted about the axis of the crankshaft 7, the spur gear 10 and the toothing 7a remain unchanged in the event of a pivoting movement of the bearing block 9. The pinion shaft 11 carries a bevel pinion 11 a, which is in engagement with a bevel gear 13. The bevel gear 13 is non-rotatably connected to a cylinder 14 and secured against axial displacement by means of a locking ring 15. The cylinder 14 is mounted above the bevel gear 13 in the housing 1 by means of a needle bearing 16. In the cylinder 14, an excitation piston 17 is axially displaceably guided. The excitation piston 17 is connected by means of a connecting rod 18 to a crank pin 7b of the crankshaft 7 and is set in a reciprocating movement when the crankshaft 7 is rotated. A percussion piston 19 is also axially displaceably guided in the cylinder 14. There is an air cushion 20 between the exciter piston 17 and the percussion piston 19, which serves to transmit the impact energy from the exciter piston 17 to the percussion piston 19. A drill 22 is inserted into a tool holder 21 and is actuated by the percussion piston 19. The rotary movement is transmitted to the drill 22 via the cylinder 14.

Der in Fig. 2 dargestellte, vergrösserte Querschnitt zeigt den Ansatz 9a des Lagerbockes, der in der Bohrung 1a des Gehäuses 1 schwenkbar gelagert ist. Da die Kurbelwelle 7 koaxial im Lagerbock 9 gelagert ist, wird durch das Schwenken des Lagerbockes 9 die Lage des Radiallagers 8 nicht verändert. Der das Schrägkugellager 12 aufnehmende Teil des Lagerbockes 9 ist mit zwei einander gegenüberliegenden Stützflächen 9b versehen. In Ausnehmungen 1b des Gehäuses 1 angeordnete Kraftmesselemente 23 werden durch die bei der Drehmomentübertragung von der Kurbelwelle 7 auf die Ritzelwelle 11 entstehenden Reaktionskräfte beansprucht. Das Signal der Kraftmesselemente 23 dient der Erzeugung von Steuerfunktionen des Handwerkzeuges und kann beispielsweise zum Abschalten der Energiezufuhr, zum Betätigen einer Kupplung oder Bremse und dgl verwendet werden. Die Kraftmesselemente 23 bestehen vorzugsweise aus Piezokeramik. Solche Elemente erzeugen bei Druckbeanspruchung eine elektrische Ladung, die in eine Spannung umgesetzt werden kann. Durch das Anordnen von zwei einander gegenüberliegenden Kraftmesselementen 23 können bei einer allfälligen Drehrichtungsumkehr des Motors 5 die auftretenden Kräfte in beiden Drehrichtungen erfasst werden.The enlarged cross section shown in FIG. 2 shows the projection 9a of the bearing block, which is pivotably mounted in the bore 1a of the housing 1. Since the crankshaft 7 is mounted coaxially in the bearing block 9, the position of the radial bearing 8 is not changed by the pivoting of the bearing block 9. The part of the bearing block 9 which receives the angular contact ball bearing 12 is provided with two opposing support surfaces 9b. Force measuring elements 23 arranged in recesses 1b of the housing 1 are stressed by the reaction forces arising during the torque transmission from the crankshaft 7 to the pinion shaft 11. The signal of the force measuring elements 23 is used to generate control functions of the hand tool and can be used, for example, to switch off the energy supply, to actuate a clutch or brake and the like. The force measuring elements 23 are preferably made of piezoceramic. Such elements generate an electrical charge when subjected to pressure, which can be converted into a voltage. By arranging two opposing force measuring elements 23, the forces occurring in both directions of rotation can be detected if the direction of rotation of the motor 5 is reversed.

Claims (2)

1. A motor-operated hand tool with a housing (1), a motor (5) arranged therein, a driving shaft (14) which is set rotating by the motor (5) and a gearing with torque measuring device arranged between the motor (5) and the driving shaft (14), characterised in that the torque measuring device comprises a gear shaft (11), a toothed wheel (6, 7a) which meshes with the gear shaft (11) and which is connected securely to a crankshaft (7) and a bearing block (9) which is mounted rotatably about the crankshaft which extends parallel to the gear shaft (11) as well as stands coaxially with the axis of rotation of the toothed wheel (6, 7a) and meshes with a motor pinion (5a), the gear shaft (11) and the crankshaft (7) being mounted in the bearing block (9) and the bearing block (9) being supported on the housing (1) by way of electrical force-measuring elements (23) made of piezoceramics.
2. A setting tool according to claim 1, characterised in that the signal of the force-measuring elements (23) serves for the generation of control functions of the band tool.
EP85810591A 1985-03-29 1985-12-12 Motor-driven hand tool Expired - Lifetime EP0199883B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3511437 1985-03-29
DE19853511437 DE3511437A1 (en) 1985-03-29 1985-03-29 MOTORIZED HAND TOOL

Publications (3)

Publication Number Publication Date
EP0199883A2 EP0199883A2 (en) 1986-11-05
EP0199883A3 EP0199883A3 (en) 1988-04-20
EP0199883B1 true EP0199883B1 (en) 1990-08-08

Family

ID=6266683

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85810591A Expired - Lifetime EP0199883B1 (en) 1985-03-29 1985-12-12 Motor-driven hand tool

Country Status (3)

Country Link
EP (1) EP0199883B1 (en)
JP (1) JPS61226278A (en)
DE (2) DE3511437A1 (en)

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US8418778B2 (en) 2010-01-07 2013-04-16 Black & Decker Inc. Power screwdriver having rotary input control
USRE44311E1 (en) 2004-10-20 2013-06-25 Black & Decker Inc. Power tool anti-kickback system with rotational rate sensor
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USRE44311E1 (en) 2004-10-20 2013-06-25 Black & Decker Inc. Power tool anti-kickback system with rotational rate sensor
USRE44993E1 (en) 2004-10-20 2014-07-08 Black & Decker Inc. Power tool anti-kickback system with rotational rate sensor
USRE45112E1 (en) 2004-10-20 2014-09-09 Black & Decker Inc. Power tool anti-kickback system with rotational rate sensor
US8727941B2 (en) 2009-11-10 2014-05-20 Makita Corporation Electric tool
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US8418778B2 (en) 2010-01-07 2013-04-16 Black & Decker Inc. Power screwdriver having rotary input control

Also Published As

Publication number Publication date
DE3511437A1 (en) 1986-10-02
DE3579160D1 (en) 1990-09-13
JPS61226278A (en) 1986-10-08
EP0199883A3 (en) 1988-04-20
EP0199883A2 (en) 1986-11-05

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