EP1175967A2 - Drehmoment Schraubendreher - Google Patents

Drehmoment Schraubendreher Download PDF

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Publication number
EP1175967A2
EP1175967A2 EP01306028A EP01306028A EP1175967A2 EP 1175967 A2 EP1175967 A2 EP 1175967A2 EP 01306028 A EP01306028 A EP 01306028A EP 01306028 A EP01306028 A EP 01306028A EP 1175967 A2 EP1175967 A2 EP 1175967A2
Authority
EP
European Patent Office
Prior art keywords
torque
pawl
ratchet
coupling
handle
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Withdrawn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
EP01306028A
Other languages
English (en)
French (fr)
Other versions
EP1175967A3 (de
Inventor
Terrence Clifford Bullen
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.)
MHH ENGINEERING CO Ltd
Original Assignee
MHH ENGINEERING CO 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 MHH ENGINEERING CO Ltd filed Critical MHH ENGINEERING CO Ltd
Publication of EP1175967A2 publication Critical patent/EP1175967A2/de
Publication of EP1175967A3 publication Critical patent/EP1175967A3/de
Withdrawn legal-status Critical Current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
    • B25B13/00—Spanners; Wrenches
    • B25B13/46—Spanners; Wrenches of the ratchet type, for providing a free return stroke of the handle
    • B25B13/461—Spanners; Wrenches of the ratchet type, for providing a free return stroke of the handle with concentric driving and driven member
    • B25B13/462—Spanners; Wrenches of the ratchet type, for providing a free return stroke of the handle with concentric driving and driven member the ratchet parts engaging in a direction radial to the tool operating axis
    • B25B13/465—Spanners; Wrenches of the ratchet type, for providing a free return stroke of the handle with concentric driving and driven member the ratchet parts engaging in a direction radial to the tool operating axis a pawl engaging an internally toothed ring
    • 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
    • B25B15/00—Screwdrivers
    • B25B15/02—Screwdrivers operated by rotating the handle
    • 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
    • B25B15/00—Screwdrivers
    • B25B15/02—Screwdrivers operated by rotating the handle
    • B25B15/04—Screwdrivers operated by rotating the handle with ratchet action

Definitions

  • This invention relates to improvements relating to torque screwdrivers.
  • Torque screwdrivers are well known in the art. Such screwdrivers generally have a shaft, a handle at one end of the shaft, and a fastener-engaging bit possibly being substituted by a plug or a socket (or other coupling) for the temporary attachment of a detachable fastener-engaging bit of a selected size and/or shape.
  • the fastener to be operated by the screwdriver may be a screw, a bolt, a nut or some other form of fastener, such fasteners having the common characteristic that they are all operated by rotation (either for tightening or loosening), the requisite torque being delivered to the fastener through the shaft of the screwdriver.
  • the coupling mechanism between the handle and the shaft is generally a ball-and-clutch mechanism, which is complex to form and fit, and therefore has a relatively high level of manufacturing cost.
  • a torque screwdriver comprising a handle, a fastener coupling, and an intermediate shaft assembly, wherein the screwdriver includes a torque coupling for rotationally coupling the handle to the fastener coupling, the torque coupling being provided by a ratchet and pawl mechanism.
  • ratchet and pawl mechanisms are considerably easier to make and/or apply to the shaft assembly of a screwdriver, thereby making such screwdrivers considerably easier and cheaper to make.
  • the parts of the ratchet and pawl mechanism may be of any suitable size, shape or design.
  • the "ratchet” is provided by a ratchet wheel having a plurality of teeth, notches, etc.
  • the pawl is a moveable catch engaging with the wheel.
  • the present invention includes any arrangement of the ratchet and pawl able to provide the torque coupling.
  • the pawl is such as to be biased to engage one or more positions on the ratchet.
  • the biasing is provided by a spring, which could be any suitable form of spring including coil springs, leaf springs, etc. More preferably, the biasing force acting on the ratchet and/or pawl is adjustable so as to provide the ability to more accurately calibrate the level of torque provided by the screwdriver.
  • the parts of the ratchet and pawl mechanism could be formed separately or integrally with the other features of the screwdriver.
  • the ratchet is formed by and/or with the handle.
  • the ratchet is formed by grooving or notching an internal part of the handle.
  • the pawl is wholly or substantially within the shaft of the shaft assembly, and is rotatable therewith.
  • the formable parts of the present invention are wholly or substantially formable by moulding, such as injection moulding, and/or machining. This significantly reduces the time and effort required to form the screwdriver.
  • a method of rotatably coupling a handle and a fastening coupling of a torque screwdriver wherein the torque coupling is provided by a ratchet and pawl mechanism.
  • Fig. 1 shows a torque screwdriver 10 having a handle 12 and a fastener coupling 14.
  • the fastener coupling 14 has a hexagon shank, and includes at one end a drive bit 16 designed to engage a suitable fastener-engaging bit.
  • a shaft assembly Between the handle 12 and the fastener coupling 14, there is a shaft assembly. One part of the assembly is a shaft 18. At the end of the shaft 18 distal from the fastener coupling 14 is a steel ball 20 for end thrust. Within and around the shaft 18 is a ratchet and pawl mechanism described in greater detail with respect to Fig. 2.
  • Fig. 2 shows, in an enlarged cross-sectional view of the handle 12, a series of longitudinal triangular notches 22 on the inner circumference thereof.
  • a pawl 24 Within the shaft 18, there is located a pawl 24.
  • One end of the pawl 24 is biased by one end of a flat leaf spring 26, which spring 26 is conjoined with the shaft 18 as further discussed below.
  • the other end of the pawl 24 is a notched head section 28 having a top projected shape designed to complement the notches 22 in the handle 12.
  • the pawl 24 is designed to be moveable 'up and down' within the shaft 18.
  • the leaf spring 26 is conjoined with the shaft 18.
  • a longitudinally sliding collar 30 having a set screw 32, such as a grub screw, therethrough to lock the position of the collar 30 on the shaft 18 where desired.
  • the screwdriver 10 also includes a retaining cover 34.
  • the shaft 18 and handle 12 can easily be machine-formed, or formed by injection moulding.
  • the fastener coupling 14 is a well-known and available part in the art.
  • the shaft 18 Once the shaft 18 has been formed, it is a simple operation to attach the flat leaf spring 26 thereto, locate the collar 30 therearound, and add the pawl 24. Because a torque screwdriver must be able to provide a predetermined degree of torque, the position of the collar 30 along the shaft 18 can be adjusted to increase or decrease the 'free' length of the leaf spring 26, and thereby to increase or decrease the force required to deflect the 'free end' of the spring 26. The force required to deflect the spring is directly related to the torsional resistance provided by the screwdriver. Once the calibration of the torque effect has been achieved, use of the set screw 32 locks the collar 30 in place around the shaft 18.
  • the shaft assembly can now be immediately located in the handle 12, and the retaining cover 34 added.
  • the retaining cover 34 provides securement, possibly irreversibly, of the shaft 18 and related parts within the handle 12.
  • the retaining cover 34 may have a 'snap fit' for ease of assembly and fitting.
  • rotation of the handle 12 by a user in an anti-clockwise fashion provides rotational coupling of the fastener coupling 14 against any suitable fastener (not shown) under the level of the pre-determined torque setting.
  • the head section 28 of the pawl 24 will travel down the angled faces of the notches 22 in the handle 12 and thereby slip into the next notch 22 when the resistance of the flat spring 26 is overcome.
  • the vertical radial faces of the head section 28 of the pawl 24 and the notches 22 also provide a solid reverse torque transmission, without the ability of the pawl 24 slipping. This thus enables tightened fasteners to be unscrewed by the screwdriver 10.
  • the number of notches 22 in the handle 12 may be any suitable number depending upon the size, shape and design of the screwdriver. In one embodiment of the present invention, there are provided an odd number of notches 22 in the handle 12.
  • the present invention provides a torque screwdriver of relatively simple construction and assembly, thereby reducing the cost of manufacture. Calibration of the torque of the screwdriver is provided by an internal moveable collar.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
EP01306028A 2000-07-17 2001-07-12 Drehmoment Schraubendreher Withdrawn EP1175967A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0017439A GB0017439D0 (en) 2000-07-17 2000-07-17 Improvements relating to torque screwdrivers
GB0017439 2000-07-17

Publications (2)

Publication Number Publication Date
EP1175967A2 true EP1175967A2 (de) 2002-01-30
EP1175967A3 EP1175967A3 (de) 2002-07-03

Family

ID=9895747

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01306028A Withdrawn EP1175967A3 (de) 2000-07-17 2001-07-12 Drehmoment Schraubendreher

Country Status (2)

Country Link
EP (1) EP1175967A3 (de)
GB (1) GB0017439D0 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2395154A (en) * 2002-11-18 2004-05-19 Chih-Ching Hsieh Screwdriver with holes to receive rod
DE10255682A1 (de) * 2002-11-28 2004-06-17 Sfs Intec Holding Ag Vorrichtung zum handbetätigten Eindrehen, Festziehen und Lösen von Befestigungsmitteln mit einem Aussen- und/oder einem Innenangriff
DE10324376B4 (de) * 2002-06-03 2007-06-21 Bobby Hu Schraubenschlüssel mit fest eingestelltem Maximal-Betriebsdrehmoment
TWI405644B (de) * 2008-12-31 2013-08-21

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2558158A (en) * 1945-09-08 1951-06-26 Vaco Products Co Safety tool handle
US2797564A (en) * 1954-08-11 1957-07-02 Joseph C Bonneau Adjustable torque tool
FR1361645A (fr) * 1963-06-18 1964-05-22 Tournevis dynamométrique
US4517865A (en) * 1984-01-06 1985-05-21 Huang Yung Lung Torque-adjustable screwdriver
DE4022763A1 (de) * 1989-07-13 1991-01-17 Biotronik Mess & Therapieg Schraubwerkzeug
US5746298A (en) * 1996-07-19 1998-05-05 Snap-On Technologies, Inc. Adjustable torque-limiting mini screwdriver

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2558158A (en) * 1945-09-08 1951-06-26 Vaco Products Co Safety tool handle
US2797564A (en) * 1954-08-11 1957-07-02 Joseph C Bonneau Adjustable torque tool
FR1361645A (fr) * 1963-06-18 1964-05-22 Tournevis dynamométrique
US4517865A (en) * 1984-01-06 1985-05-21 Huang Yung Lung Torque-adjustable screwdriver
DE4022763A1 (de) * 1989-07-13 1991-01-17 Biotronik Mess & Therapieg Schraubwerkzeug
US5746298A (en) * 1996-07-19 1998-05-05 Snap-On Technologies, Inc. Adjustable torque-limiting mini screwdriver

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10324376B4 (de) * 2002-06-03 2007-06-21 Bobby Hu Schraubenschlüssel mit fest eingestelltem Maximal-Betriebsdrehmoment
GB2395154A (en) * 2002-11-18 2004-05-19 Chih-Ching Hsieh Screwdriver with holes to receive rod
GB2395154B (en) * 2002-11-18 2006-02-01 Chih-Ching Hsieh Screwdriver structure
DE10255682A1 (de) * 2002-11-28 2004-06-17 Sfs Intec Holding Ag Vorrichtung zum handbetätigten Eindrehen, Festziehen und Lösen von Befestigungsmitteln mit einem Aussen- und/oder einem Innenangriff
TWI405644B (de) * 2008-12-31 2013-08-21

Also Published As

Publication number Publication date
EP1175967A3 (de) 2002-07-03
GB0017439D0 (en) 2000-08-30

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