WO1999050029A1 - Tournevis a frapper a commande hydraulique et son procede de commande - Google Patents

Tournevis a frapper a commande hydraulique et son procede de commande Download PDF

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Publication number
WO1999050029A1
WO1999050029A1 PCT/EP1999/002026 EP9902026W WO9950029A1 WO 1999050029 A1 WO1999050029 A1 WO 1999050029A1 EP 9902026 W EP9902026 W EP 9902026W WO 9950029 A1 WO9950029 A1 WO 9950029A1
Authority
WO
WIPO (PCT)
Prior art keywords
screw
piston
actual
pressure
angle
Prior art date
Application number
PCT/EP1999/002026
Other languages
German (de)
English (en)
Inventor
Jörg Hohmann
Frank Hohmann
Original Assignee
Hohmann Joerg
Frank Hohmann
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 Hohmann Joerg, Frank Hohmann filed Critical Hohmann Joerg
Publication of WO1999050029A1 publication Critical patent/WO1999050029A1/fr

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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
    • B25B23/145—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for fluid operated wrenches or screwdrivers
    • 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
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/004—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose of the ratchet type
    • B25B21/005—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose of the ratchet type driven by a radially acting hydraulic or pneumatic piston

Definitions

  • the invention relates to a hydraulically operated power wrench and a method for its control with a lever pivotable by a piston-cylinder unit with a ratchet arrangement for gradually rotating a ratchet bushing and a drive unit with a motor-driven, volumetric pump
  • Such a power wrench is described, for example, in DE 34 16 879 C2.
  • this power wrench there is a predetermined ratio between the piston path of the piston-cylinder unit and thus the swivel angle of the ratchet bushing and the volume flow of the volumetric pump, which is derived from the formula
  • H is the stroke of the piston-cylinder unit
  • ND is the volume of the oil introduced into the cylinder
  • AKD is the piston area of the piston of the piston-cylinder unit
  • the volume flow of the pump results from the rotational speed of the drive motor of the pump and the pump volume delivered per revolution corresponds to a specific stroke distance H of the piston-cylinder unit
  • the joint point is detected by forming the gradient of the tightening torque rd, which has a significant jump at the joint point.
  • An indication of how the actual screw clamping angle is determined in comparison to a predetermined target screw clamping angle is not found in DE 43 38 846 AI
  • the invention is based on the problem of creating a hydraulically operated power wrench and a method for controlling a hydraulically operated power wrench of the type mentioned at the beginning, by means of which the operation is simplified and operating errors are eliminated as far as possible without special requirements being placed on the specialist knowledge of the operator further damage to the screws to be tightened and to the power wrench are to be avoided, the accuracy with which the screws are tightened is increased and reliable transmission of the measurement and control signals are ensured
  • Evaluation electronics for determining a target screw clamping angle from the entered values, a scanning device for the actual screw clamping angle from the stroke of the piston-cylinder unit starting from the joint point and a control and switch-off device for switching off the movement of the piston-cylinder unit when the Target screw clamping angle are provided
  • the invention is based on the consideration that there is a geometric, unchangeable relationship between the volume flow of the pump and the stroke of the piston-cylinder unit, so that one revolution of the motor-driven, volumetric pump has a very specific stroke of the piston-cylinder unit Since this stroke distance in turn corresponds to a certain angle of rotation of the ratchet bushing, the actual screw clamping angle results directly from the revolutions of the pump by simple conversion. Accordingly, the actual screw clamping angle can be determined from the volume flow of the drive unit through the scanning device
  • the scanning device for determining the actual screw angle can have an actual pressure sensor and, when the screw is tightened, the break points of the actual pressure when the joint point is reached, when the screw rotation is inserted in the intermediate steps and when the piston of the piston-cylinder unit stops Use the interval limits for the volume flow of the drive unit at the end of the stroke, determine the actual screw angle from the volume flow within these interval limits and switch off the movement of the piston-cylinder unit when the set screw angle is reached.
  • This design of the scanning device takes advantage of the fact that when the ratchet bushing is gradually turned at the pump outlet, a steep rise in pressure begins, which changes with a bend in the pressure curve, which occurs when the screw connection is tightened up to the joint point several steps take place, at the end of each step again a kink in the pressure curve occurs when the piston-cylinder unit hits a stop at the end of the stroke path Another kink point occurs before the end of the stroke path when the joint point is reached because of At this point, the pressure rise is proportional to the bolt preload
  • the piston-cylinder unit covers the full stroke distance to the stop during each step, so that the interval between the kink point of the pressure curve at the beginning and at The end of the stroke is a measure for the respective screw clamping angle - 4 - a certain volume flow of the pump is assigned, which in turn results from its speed, there is a clear relationship between the screw clamping angle and the volume flow of the drive unit
  • the movement of the piston-cylinder unit is switched off, for example by switching off the drive unit or by opening a pressure valve in the line connection between the drive unit and the piston-cylinder unit
  • an adjustable pressure valve is arranged between the piston-cylinder unit and the pump, which can be set to a set pressure corresponding to the set preload force, and the scanning device determines the actual screw clamping angle when the set pressure is reached from the volume flow of the drive unit , it is possible to have an increase in the pressure at the pressure valve set by the scanning device if the desired screw clamping angle is not reached and to cause the screw to continue to rotate by the piston-cylinder unit until the desired screw clamping angle is reached Before reaching the target screw clamping angle, simply connect it to the interval of the pressure curve, the break point of which results from opening the pressure valve when the set target pressure is reached. Of course, this target pressure must not be set so high that when it is reached Target pressure the target - preload is exceeded
  • the input electronics, the evaluation electronics and the scanning device can preferably consist of a uniform electronic module, it is advantageous to provide an electronic pressure gauge in the line connection between the piston-cylinder unit and the drive unit as the actual pressure transducer, the measurement data of which as electrical measurement variables directly Can be used by the electronic component
  • An electronic pressure meter of this type is required if the drive motor for the volumetric pump is not an electric motor but, for example, an air motor - 5 -
  • the actual pressure sensor can be designed as a current consumption measuring device, since the current consumption of an electric motor that drives a volumetric pump is directly proportional to the pump pressure
  • the actual pressure sensor can also be designed as a phase angle measuring device
  • the scanning device for the actual pressure can preferably have a differentiating device, since the break points of the pressure curve to be recorded result from the differentiation of the actual pressure as an abrupt change in the slope and enable the break points to be determined precisely
  • the relevant volume flow of the drive unit can be calculated from the number of revolutions of the volumetric pump in the interval limits in the scanning device, preferably by the speed of revolution of the volumetric pump and the duration of the intervals of the pressure curve between the break points for calculating the Volume flow can be used
  • the method according to the invention for controlling a hydraulically operated power wrench of the type mentioned at the outset has the steps of entering a nominal preload force, the screw size, the thread pitch and the clamping length or the screw material, the material quality, the screw size, the thread pitch and the clamping length into an input electronics, Determination of a desired screw clamping angle from the entered values in an electronic evaluation unit, determination of the reaching of the joint point in a scanning device, determination of the actual screw clamping angle from the stroke of the piston-cylinder unit starting from the joint point in the scanning device and switching off the movement of the piston cylinder -Unit when the desired screw clamping angle is reached by means of a control and shutdown device
  • the scanning device can easily determine the actual screw clamping angle from the volume flow of the drive unit, the scanning device preferably having an actual pressure sensor for determining the actual screw angle and when the screw is tightened the kink points of the actual pressure when the joint point is reached Insert the screw rotation in the intermediate steps and when the piston of the piston-cylinder unit stops at the stroke end as interval limits for the volume flow - 6 -
  • the Drive unit determines the actual screw clamping angle from the volume flow within these interval limits and switches off the movement of the piston-cylinder unit when the set screw angle is reached.
  • the approach to the set screw clamping angle can advantageously be checked in such a way that between the piston
  • An adjustable pressure valve is arranged in the cylinder unit, which is set to a somewhat lower target pressure than that corresponding to the target pretensioning force.
  • the scanning device determines the actual screw tension angle from the volume flow of the drive unit when the set target pressure is reached, the If the target pressure can be exactly determined by differentiating the pressure curve at the break point, the scanning device can calculate a required further rotation angle, increase the pressure setting on the pressure valve accordingly and continue to turn the screws by the piston-cylinder unit until the target Effect the screw clamping angle and then switch off the movement of the piston-cylinder unit
  • Fig. 1 is a schematic representation of an inventive
  • Fig. 2 is a schematic representation of the pressure curve when
  • a hydraulically operated power wrench 1 comprises a piston-cylinder unit 2, a pivotable lever 3, which can be acted upon by the piston-cylinder unit 2, with a ratchet arrangement 5 for gradually turning a ratchet bushing 4
  • a swivel angle ⁇ of the lever 3 This corresponds to the full stroke of the piston-cylinder unit. Accordingly, there is a fixed geometric relationship between the stroke H and the swivel angle
  • the pivoting of the pivot lever 3 for tightening a screw, not shown, is carried out by applying pressure oil to the piston-cylinder unit 2 from a drive unit 6, while the return stroke of the lever 3 is effected by a return spring, not shown.
  • the return stroke takes place as an idle stroke, since the ratchet arrangement 5 releases the rotary connection between the lever 3 and the ratchet bush 4 on the return stroke
  • the drive unit 6 has two pumps 7, 8 connected in parallel, which act as piston pumps - 7 - are designed with different delivery volumes
  • the pumps 7, 8 are driven by a common drive motor 9, which in the exemplary embodiment shown is designed as an electric motor.
  • a combined switchover and pressure control valve 11 is connected to the pressure side of the pumps 7, 8, the latter Operation will be explained furthermore.
  • a pressure sensor 12 is also arranged in the pressure line to the power wrench 1. Instead of a pressure sensor 12 arranged in the pressure line, the pressure in the pressure line can also be measured by a current consumption measuring device 13 connected to the drive motor 9 or by a drive motor 9 connected phase angle measuring device 14 take place
  • a tachometer generator 15 can also be connected to the drive motor 9
  • An electronic control unit 16 controlling the drive unit 6 is connected to an input electronics 17, preferably an input keyboard, and has inputs for the pressure sensor 12 and / or the current consumption measuring device 13 and / or the phase angle measuring device 14 and / or the tachometer generator 15.
  • An output of the electronic ones Control unit 16 is connected to the changeover and pressure control valve 11.
  • the electronic control unit 16 comprises evaluation electronics 18 for determining a desired screw tension angle from the screw values entered into the input electronics 17, namely a desired preload force, the screw size, the thread pitch and the clamping length
  • the electronic control unit 16 comprises a scanning device 19 for the actual screw clamping angle and a control and switch-off device 20 for switching off the movement of the piston-cylinder unit 2 when the desired screw clamping angle is reached.
  • a differentiating device 21 in the elect Ronic control unit 16 serves to represent the break points Ai to As, B] to B3 and C] to C from the pressure curve shown in FIG. 2 when tightening a screw connection as a sudden change in the pressure rise and for evaluation in the scanning device 19 and the control and To provide shutdown device 20
  • the nominal preload force, the screw size, the thread pitch and the clamping length are entered into the input electronics 17 and from there to the evaluation electronics 18 in the electronic control unit 16.
  • the evaluation electronics 18 determines a nominal bolt preload angle from these screwing data, since the SoH preload force corresponds to a certain screw elongation, which in turn is directly related to the thread pitch - 8 - there is a proportional relationship to the nominal screw clamping angle
  • the target preload is determined by the modulus of elasticity of the screw material, the permissible tensile stress, i.e. the material quality, the shaft cross-section and the screw length and can be specified, for example, on the screw itself or in a table.
  • the evaluation electronics can also determine the target preload, however the screw material and the screw quality are entered in addition to the screw size, the thread pitch and the clamping length
  • This desired screw tension angle is only measured from the joint point B3, that is to say from the point at which the various components of the screw connection lie snugly.
  • This joint point is designated B3 in FIG.
  • the pressure curve can be determined either by means of an electronic pressure sensor 12 arranged in the pressure line or by a current consumption measuring device 13 connected to the drive motor 9 or by a phase angle measuring device 14 connected to the drive motor 9 by differentiating the pressure curve using the differentiating device 21 in
  • the break points A] to A ⁇ Bl to B3 and C] to Cß can be determined very precisely, so that the actual screw clamping angle can be compared at any time with the target screw clamping angle
  • the switching off of the movement of the piston-cylinder unit 2 when the desired screw clamping angle is reached can be controlled in different ways.
  • the changeover and pressure control valve 11 is set to a maximum pressure pmax, which is always higher than the pressure which is reached when it is reached of the desired screw clamping angle in the pressure line, it is necessary to send a signal from the control and shutdown device 20 in the electronic control unit 16 to the drive motor 9 or to the changeover and pressure control valve 11, which drives the drive motor 9 when the setpoint is reached -
  • pmax a maximum pressure pmax
  • the pressure relief valve for the pump 8 can also be set so that a part of the intervals 11 to I5 is still detected by both pumps 7, 8 when one - 1 1 - particularly fast screwing is desired
  • the invention has the particular advantage that a highly precise tightening of a screw connection to a predeterminable target preload force can be achieved via a target bolt tension angle that can be calculated therefrom, without the actual bolt tension angle having to be measured directly by means of a special angle measuring device, since the The actual screw clamping angle can be determined from the volume flow of the hydraulic drive unit 6 for the power wrench 1 and this volume flow is geometrically predetermined from the dimensions of the pumps 7, 8 and their speed

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)

Abstract

L'invention concerne un tournevis à frapper à commande hydraulique et un procédé permettant d'assurer sa commande. Ce tournevis à frapper comprend un levier pouvant pivoter à l'aie d'une unité piston-cylindre avec un système de cliquet pour permettre une rotation pas-à-pas d'un manchon de cliquet, une unité d'entraînement avec une pompe volumétrique motorisée, une unité électronique de saisie pour introduire une force de précontrainte théorique, la dimension des vis, le pas de vis et la longueur de serrage, ainsi qu'une unité électronique d'évaluation pour déterminer un angle de serrage de vis réel sur la base de la course de l'unité piston-cylindre, à partir du point d'assemblage. Le tournevis à frapper comprend en outre un dispositif de déconnexion pour arrêter le mouvement de l'unité piston-cylindre lorsque l'angle de serrage de vis est atteint.
PCT/EP1999/002026 1998-03-28 1999-03-25 Tournevis a frapper a commande hydraulique et son procede de commande WO1999050029A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1998113900 DE19813900A1 (de) 1998-03-28 1998-03-28 Hydraulisch betriebener Kraftschrauber und Verfahren zu seiner Herstellung
DE19813900.4 1998-03-28

Publications (1)

Publication Number Publication Date
WO1999050029A1 true WO1999050029A1 (fr) 1999-10-07

Family

ID=7862768

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1999/002026 WO1999050029A1 (fr) 1998-03-28 1999-03-25 Tournevis a frapper a commande hydraulique et son procede de commande

Country Status (2)

Country Link
DE (1) DE19813900A1 (fr)
WO (1) WO1999050029A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007532331A (ja) * 2004-04-14 2007-11-15 ワグナー ポール−ハインツ 部品の角度制御された回転方法
EP3653888B1 (fr) 2018-11-13 2023-01-25 Enerpac Tool Group Corp. Système d'alimentation hydraulique et son procédé de commande

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE300396T1 (de) * 2002-09-19 2005-08-15 Alexander Kipfelsberger Hydraulik-ratschenschrauber mit einem doppeltwirkenden hydraulik-zylinder-kolben- antrieb
DE102004057402B4 (de) * 2004-11-26 2007-03-29 Schraubtechnik Neef Gmbh Verfahren zur Steuerung der Druckversorgung einer an eine Druckquelle angeschlossenen hydraulischen Kolben-Zylindereinheit und hydraulische Antriebseinrichtung
DE102004058338A1 (de) * 2004-12-02 2006-06-08 Werner, Karl-Heinz, Dipl.-Ing. Steuerung eines Schraubvorgangs
DE102005019258B4 (de) * 2005-04-26 2009-02-12 Junkers, Holger, Dipl.-Ing.(FH) Verfahren zur Schraubstellenanalyse und zum streckgrenzengesteuerten Anziehen von Schraubverbindungen unter Einsatz intermittierend arbeitendender Schraubwerkzeuge
DE102008019765A1 (de) * 2008-04-18 2009-10-22 Hohmann, Jörg Verfahren und Vorrichtung zum Steuern eines hydraulisch betriebenen Kraftschraubers
DE102010009712A1 (de) * 2010-01-08 2011-07-14 Liebherr-Werk Nenzing GmbH, Vorarlberg Verfahren zum Anziehen einer Schraubverbindung unter Längung der Schraube
DE102010020258A1 (de) * 2010-05-11 2011-11-17 Lösomat Schraubtechnik Neef Gmbh Schaltungsanordnung zum Betreiben eines Drehmomentschraubers oder dergleichen

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3318910A1 (de) * 1983-05-25 1984-11-29 Oskar Ing.(grad.) 7073 Lorch Mohilo Verfahren und einrichtung zum programmieren eines elektronischen schraubenschluessels
DE3327964A1 (de) * 1983-08-03 1985-02-28 Oskar Ing.(grad.) 7073 Lorch Mohilo Verfahren zum identifizieren von verbindungsschrauben nach typ und/oder anziehvorschrift
DE3416879A1 (de) 1984-05-08 1985-11-14 Hohmann, Hans, 5778 Meschede Hydraulisch betriebener kraftschrauber
EP0297515A1 (fr) * 1987-06-29 1989-01-04 SPS TECHNOLOGIES, Inc. Tournevis qui, tout en conservant une valeur limite apparente d'élasticité, est capable d'enregistrer une modification du moment de force et un déplacement angulaire
DE4331846A1 (de) 1992-09-30 1994-03-31 Volkswagen Ag Verfahren zum Anziehen einer Schraubverbindung
US5668328A (en) * 1996-07-17 1997-09-16 Applied Power Inc. Method and apparatus for hydraulically tightening threaded fasteners

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007153A (en) * 1989-06-29 1991-04-16 Junkers John K Method for tightening threaded connectors

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3318910A1 (de) * 1983-05-25 1984-11-29 Oskar Ing.(grad.) 7073 Lorch Mohilo Verfahren und einrichtung zum programmieren eines elektronischen schraubenschluessels
DE3327964A1 (de) * 1983-08-03 1985-02-28 Oskar Ing.(grad.) 7073 Lorch Mohilo Verfahren zum identifizieren von verbindungsschrauben nach typ und/oder anziehvorschrift
DE3416879A1 (de) 1984-05-08 1985-11-14 Hohmann, Hans, 5778 Meschede Hydraulisch betriebener kraftschrauber
EP0297515A1 (fr) * 1987-06-29 1989-01-04 SPS TECHNOLOGIES, Inc. Tournevis qui, tout en conservant une valeur limite apparente d'élasticité, est capable d'enregistrer une modification du moment de force et un déplacement angulaire
DE4331846A1 (de) 1992-09-30 1994-03-31 Volkswagen Ag Verfahren zum Anziehen einer Schraubverbindung
US5668328A (en) * 1996-07-17 1997-09-16 Applied Power Inc. Method and apparatus for hydraulically tightening threaded fasteners

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007532331A (ja) * 2004-04-14 2007-11-15 ワグナー ポール−ハインツ 部品の角度制御された回転方法
EP3653888B1 (fr) 2018-11-13 2023-01-25 Enerpac Tool Group Corp. Système d'alimentation hydraulique et son procédé de commande

Also Published As

Publication number Publication date
DE19813900A1 (de) 1999-09-30

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