EP0063460B1 - Motorgetriebenes Gerät - Google Patents

Motorgetriebenes Gerät Download PDF

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Publication number
EP0063460B1
EP0063460B1 EP82301895A EP82301895A EP0063460B1 EP 0063460 B1 EP0063460 B1 EP 0063460B1 EP 82301895 A EP82301895 A EP 82301895A EP 82301895 A EP82301895 A EP 82301895A EP 0063460 B1 EP0063460 B1 EP 0063460B1
Authority
EP
European Patent Office
Prior art keywords
motor
torque
hall effect
sensitive device
power tool
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
Application number
EP82301895A
Other languages
English (en)
French (fr)
Other versions
EP0063460A3 (en
EP0063460A2 (de
Inventor
Simon Patrick Brown
Joshua Nee Adjah Okunor
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.)
Air Compressors and Tools Ltd
Original Assignee
Desoutter Ltd
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 Desoutter Ltd filed Critical Desoutter Ltd
Priority to AT82301895T priority Critical patent/ATE24140T1/de
Publication of EP0063460A2 publication Critical patent/EP0063460A2/de
Publication of EP0063460A3 publication Critical patent/EP0063460A3/en
Application granted granted Critical
Publication of EP0063460B1 publication Critical patent/EP0063460B1/de
Expired legal-status Critical Current

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Classifications

    • 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

Definitions

  • This invention relates to a motor driven power tool, e.g. a screwdriver and more particularly but not exclusively to an electric motor driven power tool.
  • a power tool comprising a casing having a tool holder and a motor mounted therein, a torque sensitive device between the motor and the tool holder and switch means operable to cut off the motor when a torque above a predetermined value is transmitted across the device.
  • the present invention is characterised in that the switch means includes a Hall effect device, comprising a stationary Hall effect element and a magnet movable relative to the Hall effect element when the torque transmitted across the torque sensitive device exceeds said predetermined value.
  • a Hall effect device comprising a stationary Hall effect element and a magnet movable relative to the Hall effect element when the torque transmitted across the torque sensitive device exceeds said predetermined value.
  • the Hall effect device can provide a low inertia non-contact arrangement for cutting off the motor when the torque exceeds said predetermined value.
  • the torque sensitive device comprises torque sensitive device parts movable axially relative to each other when the torque exceeds said predetermined value to move the magnet relative to the Hall effect element.
  • the Hall effect device is interposed between the motor and the torque sensitive device.
  • the motor and the torque sensitive device may be axially spaced apart with the Hall effect device adjacent to the motor and in this case, an elongate actuating member, e.g. a push rod, couples the torque sensitive device to the magnet of the Hall effect device.
  • a gear-box may be interposed between the motor and torque sensitive device, in which case the elongate actuating member will extend through the gear-box.
  • the motor is an electric motor.
  • a switch may be provided for reversing the direction of the motor.
  • the switch means including the Hall effect device, may be operable to energise the motor in response to axial movement of the torque sensitive device towards the motor.
  • the motor may be energised by a switch mounted on the body of the . tool.
  • a power tool 10 in the form of a screwdriver, which is driven by an electric motor 11.
  • the tool 10 has a tubular casing 12 which contains the motor drivingly connected to a shaft 13 via a gear box 14.
  • a clutch has a driving member 15, which is integral with the shaft 13 so as to be rotated therewith, and a driven member 16, integral with a tool holder 17 which is mounted in a bearing sleeve 18 fixed in one end of the casing 12 and is adapted to releasably locate a screwdriver bit (not shown).
  • One clutch member is constituted by a boss 20 at the rear end of the driven member 16 and the other clutch member by balls 21 carried in radial passages formed in the forward end of the driving member 15.
  • the balls are biassed by means of a spring-loaded sleeve 22 mounted on the surface member 15 and having a frusto- conical end surface 23 which engages the balls.
  • Compression spring 24 pushes the sleeve 22 over the balls and the end surface 23 pushes them in towards the axis of the clutch.
  • a latch sleeve 27 is also mounted on the shaft 13 so as to be axially slidable therealong and is biassed towards the rear end of the collar 26 by a compression spring 28.
  • a thrust bearing 29 is interposed between the collar 26 and the sleeve 22 so that the sleeve 22 can rotate freely relative to the spring 24 which is under compression and which engages the block 25 keyed as aforesaid to the shaft 13.
  • the sleeve 22 is free to rotate about the driving member 15 so that as the balls 21 are cammed outwards as hereinafter more fully explained, they will rotate about axes parallel with the tool axis so that there is no sliding between the ball surface and either of the surfaces with which the balls are in contact.
  • the shaft 13 is splined to the output member of the gearbox 14 so as to be axially slidable relative thereto.
  • a compression spring 30 urges the shaft 13 and hence driving and driven members 15 and 16 respectively forwards until a shoulder 31 on the driven member 16 engages the bearing sleeve 18.
  • a push rod 32 which operates the motor as explained hereinafter extends through the gear- box 14, and into the shaft 13 where it engages a latch bolt 33.
  • the shaft 13 has radial passages which accommodate balls 34.
  • the balls 34 normally project into an annular recess in the latch bolt 33 where they are retained by the latch sleeve 27, but the sleeve 27 and collar 26 define an annular groove 35 which when aligned with the passages accommodating the balls 34 as hereinafter described allows the balls 34 to move radially away from the axis of the shaft.
  • the boss 20 is of generally square cross-section but each face has a detent recess adjacent to the trailing edge of the face when viewed in the direction of forward rotation of the boss 20.
  • detent recesses will be explained hereinafter.
  • the rear end of the push rod 32 has a piston 36 attached thereto.
  • the rear face of the piston 36 bears against a permanent magnet 37 which together with the piston 36 is axially slidably mounted in a hollow non-magnetic transmission shaft 38 which drivably connects the electric motor 11 to a pinion 39 at the input end of the gearbox 14.
  • a non-magnetic permanent magnet return spring 40 is disposed within the transmission shaft 38 between the magnet 37 and a spacer 41.
  • Surrounding the transmission shaft and fixed against angular movement relative to the casing 12 is an axially adjustable non-magnetic carrier 42 for a Hall effect element 43.
  • the Hall effect element 43 connected to a Hall effect enable switch 44 which is in turn connected to a power switching circuit 45 operable to supply power to the motor 11.
  • the tool is provided with a touch switch pad 46 which is activated by the pressure of a conductive mass of significant size in contact with the pad.
  • An output signal of the touch switch is conditioned by a conditioning circuit 47 to provide a digital signal fed to a phase splitter 48 which in turn sets the power switching circuit into a forward or reverse state.
  • the screwdriver bit In operation, the screwdriver bit is located in the head of the screw and sufficient thrust is applied to compress the springs 30 & 40.
  • the push rod 32 and the permanent magnet move rearwardly and this operates the Hall effect device so that power is supplied to the motor 11.
  • the torque is transmitted from the shaft 13 through the driving member 15 and the balls 21 to the driven member 16 and the screwdriver bit.
  • the balls 21 grip the boss 20, and the driving and driven members 15 and 16 respectively rotate in unison with the balls.
  • the balls 34 are allowed to move radially away from the axis of the shaft 13 and such movement releases the latch bolt 33 which will move axially forward under the influence of return spring 40. Hence, the magnet moves forwardly and the Hall effect element operates to denergize the motor. Due to the influence of any stored energy in the motor and gearbox, the driving member 15 will continue to rotate and the balls 21 will pass over the edge of the cam surfaces on the boss 20.
  • the position of the block 25 can be adjusted along the axis of the driving member 13 in order to vary the compression in the spring 24.
  • the torque at which the sleeve 22 will move to release the push rod 32 can be varied.
  • each detent recess may be replaced with an ear which presents a more steeply inclined camming. surface (i.e. a surface with a greater approach angle) to the balls than the remainder of the camming surface. Therefore, once again the balls 21 will need to have a greater force applied to them to overcome this steeper slope when the tool is operated in a reverse direction.
  • Hall effect device comprising Hall effect element 43 and magnet 37, allows the push rod 32, push rod piston 36, magnet 37, ' and return spring 40 to slide freely within rotating parts whilst providing a compact arrangement. Moreover, the system has low inertia as only the push rod piston 36, magnet 37 and return spring 40 affect the response time of the system.
  • the torque sensitive clutch could be moved rearwardly towards the motor 11 by a lever mechanism (not shown) to energize the motor.
  • the tool holder could be fixed against axial movement.
  • the reverse mode of switching could be employed where the magnet 37 moves out of line with the Hall effect element to energise the motor.
  • the sleeve 22 could act on the forward end of the push rod such as through the intermediary of a pin connected to the sleeve 22 and extending through slots in the shaft diametrically across the bores of the shaft 13.
  • the motor may be energised by a touch sensitive switch mounted on the body of the tool.
  • the push rod 32 moves the magnet 37 momentarily away from (or into line with) the Hall- effect element.
  • the motor is switched off and an electric latching circuit holds the motor off until the pressure on the touch sensitive switch is released and, when required, re-applied.
  • This arrangement is particularly applicable to a tool with an angle head i.e.withtheaxisofthetool holder at an angle, e.g. 90°, to the axis of the motor (and clutch).
  • the torque sensitive clutch could be replaced by any other appropriate torque sensitive device.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
  • Portable Nailing Machines And Staplers (AREA)
  • Power Steering Mechanism (AREA)
  • Control Of Electric Motors In General (AREA)
  • Control Of Direct Current Motors (AREA)

Claims (8)

1. Motorgetriebenes Gerät mit einem Gehäuse (12), in dem ein Werkzeughalter (17) und ein Motor (11) angeordnet sind, mit einer drehmomentempfindlichen Vorrichtung (15, 16, 21, 22) zwischen dem Motor und dem Werkzeughalter, und mit Schaltmitteln zum Abschalten des Motors, wenn ein Drehmoment oberhalb eines vorbestimmten Wertes über die Vorrichtung übertragen wird, dadurch gekennzeichnet, daß die Schaltmittel eine Hall-Effekt-Einrichtung einschließen mit einem stationären Hall-Effekt-Element (43) und einem Magneten (37), der relativzum Hall-Effekt-Element beweglich ist, wenn das über die drehmomentempfindliche Vorrichtung übertragene Drehmoment den vorbestimmten Wert übersteigt.
2. Motorgetriebenes Gerät nach Anspruch 1, dadurch gekennzeichnet, daß die drehmomentempfindliche Vorrichtung drehmomentempfindliche Vorrichtungsteile (15, 16, 22) umfaßt, die relativ zueinander axial beweglich sind, wenn das Drehmoment den vorgegebenen Wert übersteigt, umd den Magneten relativ zum Hall-Effekt-Element zu bewegen.
3. Motorgetriebenes Gerät nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Motor und die drehmomentempfindliche Vorrichtung axial räumlich voneinander getrennt sind, daß die Hall-Effekt-Einrichtung neben dem Motor liegt, und daß ein längliches Betätigungsglied (32) die drehmomentempfindliche Vorrichtung an den Magneten der Hall-Effekt-Einrichtung kuppelt.
4. Motorgetriebenes Gerät nach Anspruch 3, dadurch gekennzeichnet, daß zwischen den Motor und die drehmomentempfindliche Vorrichtung ein Getriebe (14) eingeschaltet ist, und daß sich das längliche Betätigungsglied durch das Getriebe hindurch erstreckt.
5. Motorgetriebenes Gerät nach einem der voranstehenden Ansprüche, dadurch gekennzeichnet, daß die Hall-Effekt-Einrichtung zwischen dem Motor und der drehmomentempfindlichen Vorrichtung angeordnet ist.
6. Motorgetriebenes Gerät nach einem der voranstehenden Ansprüche, dadurch gekennzeichnet, daß der Motor ein Elektromotor ist.
7. Motorgetriebenes Gerät nach Anspruch 7, gekennzeichnet durch einen Schalterzur Umkehr der Laufrichtung des Motors.
8. Motorgetriebenes Gerät nach einem der voranstehenden Ansprüche, dadurch gekennzeichnet, daß die Schaltmittel so betätigbar sind, daß der Motor in Abhängigkeit von einer Axialverschiebung der drehmomentempfindlichen Vorrichtung zum Motor eingeschaltet wird.
EP82301895A 1981-04-13 1982-04-08 Motorgetriebenes Gerät Expired EP0063460B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82301895T ATE24140T1 (de) 1981-04-13 1982-04-08 Motorgetriebenes geraet.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8111620 1981-04-13
GB8111620 1981-04-13

Publications (3)

Publication Number Publication Date
EP0063460A2 EP0063460A2 (de) 1982-10-27
EP0063460A3 EP0063460A3 (en) 1984-01-04
EP0063460B1 true EP0063460B1 (de) 1986-12-10

Family

ID=10521122

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82301895A Expired EP0063460B1 (de) 1981-04-13 1982-04-08 Motorgetriebenes Gerät

Country Status (4)

Country Link
EP (1) EP0063460B1 (de)
AT (1) ATE24140T1 (de)
DE (1) DE3274631D1 (de)
GB (1) GB2096510B (de)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61121877A (ja) * 1984-11-16 1986-06-09 松下電器産業株式会社 電動ドライバ−
DE3443670A1 (de) * 1984-11-30 1986-06-05 C. & E. Fein Gmbh & Co, 7000 Stuttgart Kraftgetriebene schraubvorrichtung mit variabler drehmomenteinstellung
GB2195569B (en) * 1986-10-01 1990-04-04 Desoutter Ltd Power tools
SE461510B (sv) * 1986-11-27 1990-02-26 Atlas Copco Ab Aktiveringsarrangemang vid elektrisk skruvdragare
DE3786266T2 (de) * 1987-09-30 1993-12-02 Ibm Vorrichtung zum Anschluss einer Datenverarbeitungseinrichtung an ein Telefonnetz.
DE4019895C2 (de) * 1990-06-22 1999-04-08 Ceka Elektrowerkzeuge Ag & Co Verfahren und Vorrichtung zur Steuerung des Betriebs von Elektrohandgeräten
JP2721768B2 (ja) * 1992-03-12 1998-03-04 リョービ株式会社 バッテリー式スクリュードライバー
GB2271522B (en) * 1992-10-08 1995-03-29 Desoutter Ltd Power tool with control means responsive to reaction torque
US5310010A (en) * 1993-08-05 1994-05-10 Lo Juey Y Automatic overload release and power stoppage device
US5738177A (en) * 1995-07-28 1998-04-14 Black & Decker Inc. Production assembly tool
DE19737234B4 (de) * 1997-08-27 2004-03-11 Scintilla Ag Werkzeug, insbesondere Akkuschrauber
DE19738094C1 (de) * 1997-09-01 1999-03-04 Bosch Gmbh Robert Schlagschrauber
JP2012135845A (ja) * 2010-12-27 2012-07-19 Makita Corp 作業工具

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1457496A (en) * 1975-04-30 1976-12-01 Desoutter Brothers Ltd Power operated torque applying tool

Also Published As

Publication number Publication date
ATE24140T1 (de) 1986-12-15
EP0063460A3 (en) 1984-01-04
GB2096510A (en) 1982-10-20
GB2096510B (en) 1985-01-23
DE3274631D1 (en) 1987-01-22
EP0063460A2 (de) 1982-10-27

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