WO2014146894A1 - Safety coupling in a power wrench with a flywheel reaction torque absorber - Google Patents

Safety coupling in a power wrench with a flywheel reaction torque absorber Download PDF

Info

Publication number
WO2014146894A1
WO2014146894A1 PCT/EP2014/054135 EP2014054135W WO2014146894A1 WO 2014146894 A1 WO2014146894 A1 WO 2014146894A1 EP 2014054135 W EP2014054135 W EP 2014054135W WO 2014146894 A1 WO2014146894 A1 WO 2014146894A1
Authority
WO
WIPO (PCT)
Prior art keywords
flywheel
housing
bearings
power wrench
power
Prior art date
Application number
PCT/EP2014/054135
Other languages
French (fr)
Inventor
Robin McGOUGAN
Karl Johan Lars Elsmark
Original Assignee
Atlas Copco Industrial Technique Ab
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 Atlas Copco Industrial Technique Ab filed Critical Atlas Copco Industrial Technique Ab
Publication of WO2014146894A1 publication Critical patent/WO2014146894A1/en

Links

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
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2322/00—Apparatus used in shaping articles
    • F16C2322/50—Hand tools, workshop equipment or manipulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D7/00—Slip couplings, e.g. slipping on overload, for absorbing shock
    • F16D7/02—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type
    • F16D7/021—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type with radially applied torque-limiting friction surfaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D7/00—Slip couplings, e.g. slipping on overload, for absorbing shock
    • F16D7/02—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type
    • F16D7/024—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type with axially applied torque limiting friction surfaces
    • F16D7/025—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type with axially applied torque limiting friction surfaces with flat clutching surfaces, e.g. discs

Definitions

  • the invention relates to a manually supported power wrench comprising a housing with a rotation motor, a power transmission and an output shaft, wherein the power transmission includes a flywheel reaction torque absorber.
  • the invention concerns a power wrench of the above type wherein the housing is provided with a handle for operator control of the wrench.
  • the basic idea behind a power wrench of the above type is to protect the operator from uncomfortable reaction forces by having the flywheel absorb part of the reaction torque transferred to the housing during tightening of screw joints and/or having kinetic energy of the flywheel boost the output torque at the end of the tightening process.
  • the flywheel may also be arranged to boost the output speed during an initial phase of a tightening process. In order to achieve any of these objects the flywheel may be accelerated to relatively high speed levels. This means that if the flywheel bearings or anything else would break down or accidentally cause mechanical contact between the flywheel and the housing during operation of the wrench the relatively high kinetic energy of the flywheel would be transferred to the housing, which would result in the operator being exposed to a rather violent and hazardous reaction force.
  • Fig. 1 shows a side view partly in section of a power wrench according to one embodiment of the invention.
  • Fig. 2 shows a similar view of an alternative embodiment of the invention .
  • Fig. 3 shows on a larger scale fraction III of the power wrench in Fig. 2 illustrating the cylindrical wall of the housing provided with a friction lining.
  • the power wrench shown in Fig. 1 comprises a housing with a handle 11 for operator control of the wrench.
  • the housing is divided into two parts, namely a rear part 10a and a forward part 10b.
  • the wrench includes a rotation motor with an output spindle 12, a power
  • the power transmission comprises a drive spindle 16 connected to the output spindle 12 of the motor, a planetary gearing and a flywheel 20.
  • the planetary gearing comprises a sun gear 18 that is connected to a drive spindle 16 that in turn is connected to the output spindled 12.
  • the sun gear 18 is arranged to drive a couple of planet wheels 19 that are interconnected by means of a planet carrier 21, which is formed as one piece member with the output shaft 15.
  • a surrounding gear rim 22 of the planetary gearing is connected to the flywheel 20 via a disc shaped connection portion 23.
  • the flywheel 20 is rotatively supported relative to the forward housing part 10b by means of two bearings 24.
  • the housing comprises a rear half 10a which is formed with the handle 11 and which supports the motor, and a forward part 10b containing the power transmission 14.
  • the rear half 10a and the forward part 10b are interconnected via a release coupling 30.
  • the release coupling 30 is arranged to prevent the operator from being exposed to hazardous forces.
  • the release coupling 30 is arranged to prevent rotation between the two housing parts 10a, 10b during normal operation of the wrench, but to allow relative rotation between the two housing parts 10a, 10b in an emergency case, i.e. in case of a dead stop of the flywheel 20 relative to the forward housing part 10b.
  • the release point of the coupling 30 may be adjusted and set by means of the clamp nut 28.
  • the forward housing part 10b has a rear axially extending ring shaped flange 25 which is rotatively supported on a radial flange 26 on the rear housing part 10a and axially locked relative thereto by a clamp nut 28 threaded onto the axial flange 25.
  • a clamp nut 28 threaded onto the axial flange 25.
  • On both sides of the radial flange 26 there are provided two friction rings 29 which are clamped into frictional contact with the radial flange 26 by the clamp nut 28.
  • This arrangement forms a friction type release coupling 30 between the two housing parts 10a and 10b and has the purpose of preventing accidental hazardous forces emanating from the kinetic energy of the flywheel 20 to reach the rear housing part 10a and thereby the operator via the handle 11.
  • Such accidental sudden mechanical interconnection between the flywheel 20 and the forward housing part 10b may be caused by a brake down of the bearing with an abrupt stop of the flywheel 20 as a result.
  • the operation order of the power transmission 14 including the flywheel 20 as well as the control of the motor during a screw joint tightening process may be arranged in different ways and is not the object of the invention it is not described in further detail in this specification.
  • the basic idea of the flywheel arrangement is to obtain a reaction torgue absorption during a tightening processes to thereby protect the operator from uncomfortable and tiresome reaction forces. This means that the flywheel 20 may attain rather high speed at some instances which means that it contains a high kinetic energy.
  • Fig. 2 there is illustrated an alternative embodiment of the invention wherein the forward and rear housing parts 10a and 10b are rigidly interconnected, but instead a release coupling 44 is provided between the flywheel supporting bearings 24 and the flywheel 20 itself.
  • a release coupling 44 is instead provided between the flywheel supporting bearings 24 and the housings 10a, 10b.
  • a low friction lining 40 may be provided the on inner wall of the forward housing part 10b. See Fig. 3.
  • a low friction lining may be provided on the outer surface of the flywheel 20.
  • the friction type release couplings may have alternative designs and may even be replaced by other types of couplings with the same protective characteristics to protect the operator from dangerous forces in case of malfunction of the power wrench.
  • the friction ring arrangement could be replaced by any kind of cam mechanism or even a breakpin dimensioned to withstand reaction forces developed during normal wrench operation but to be sheared off and break the connection between the housing halves in case of a sudden flywheel stop.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)

Abstract

A manually supported power wrench comprising a housing (10a, 10b) with a handle (11), a rotation motor, a power transmission (14) containing a reaction torque absorbing flywheel (20) rotatively supported on bearings (24) in the housing (10a, 10b), wherein a release coupling (30;44) is provided to prevent transfer hazardous kinetic energy from the flywheel (20) to the housing (10a, 10b) in case of a dead stop of the flywheel (20) at mechanical breakdown of the power transmission (14).

Description

Safety coupling in a power wrench with a flywheel reaction torque absorber .
The invention relates to a manually supported power wrench comprising a housing with a rotation motor, a power transmission and an output shaft, wherein the power transmission includes a flywheel reaction torque absorber. In particular, the invention concerns a power wrench of the above type wherein the housing is provided with a handle for operator control of the wrench.
The basic idea behind a power wrench of the above type is to protect the operator from uncomfortable reaction forces by having the flywheel absorb part of the reaction torque transferred to the housing during tightening of screw joints and/or having kinetic energy of the flywheel boost the output torque at the end of the tightening process. The flywheel may also be arranged to boost the output speed during an initial phase of a tightening process. In order to achieve any of these objects the flywheel may be accelerated to relatively high speed levels. This means that if the flywheel bearings or anything else would break down or accidentally cause mechanical contact between the flywheel and the housing during operation of the wrench the relatively high kinetic energy of the flywheel would be transferred to the housing, which would result in the operator being exposed to a rather violent and hazardous reaction force.
It is an object of the invention to provide a power wrench of the above described type that includes a means for protecting the operator from any hazardous forces in case of a breakdown of any part of the wrench that would cause a sudden interconnection between the flywheel and the housing, whereby the kinetic energy of the flywheel is prevented from reaching and harming the operator.
Further objects and advances of the invention will appear from the following specification and claims. Preferred embodiments of the invention are described below with reference to the accompanying drawings.
In the drawings
Fig. 1 shows a side view partly in section of a power wrench according to one embodiment of the invention.
Fig. 2 shows a similar view of an alternative embodiment of the invention .
Fig. 3 shows on a larger scale fraction III of the power wrench in Fig. 2 illustrating the cylindrical wall of the housing provided with a friction lining.
The power wrench shown in Fig. 1 comprises a housing with a handle 11 for operator control of the wrench. The housing is divided into two parts, namely a rear part 10a and a forward part 10b. The wrench includes a rotation motor with an output spindle 12, a power
transmission, and an output shaft 15 for connection to a screw joint to be tightened. The power transmission comprises a drive spindle 16 connected to the output spindle 12 of the motor, a planetary gearing and a flywheel 20. The planetary gearing comprises a sun gear 18 that is connected to a drive spindle 16 that in turn is connected to the output spindled 12. The sun gear 18 is arranged to drive a couple of planet wheels 19 that are interconnected by means of a planet carrier 21, which is formed as one piece member with the output shaft 15. A surrounding gear rim 22 of the planetary gearing is connected to the flywheel 20 via a disc shaped connection portion 23. The flywheel 20 is rotatively supported relative to the forward housing part 10b by means of two bearings 24.
As mentioned above, the housing comprises a rear half 10a which is formed with the handle 11 and which supports the motor, and a forward part 10b containing the power transmission 14. In a first embodiment of the invention the rear half 10a and the forward part 10b are interconnected via a release coupling 30. The release coupling 30 is arranged to prevent the operator from being exposed to hazardous forces. The release coupling 30 is arranged to prevent rotation between the two housing parts 10a, 10b during normal operation of the wrench, but to allow relative rotation between the two housing parts 10a, 10b in an emergency case, i.e. in case of a dead stop of the flywheel 20 relative to the forward housing part 10b. The release point of the coupling 30 may be adjusted and set by means of the clamp nut 28. The forward housing part 10b has a rear axially extending ring shaped flange 25 which is rotatively supported on a radial flange 26 on the rear housing part 10a and axially locked relative thereto by a clamp nut 28 threaded onto the axial flange 25. On both sides of the radial flange 26 there are provided two friction rings 29 which are clamped into frictional contact with the radial flange 26 by the clamp nut 28. This arrangement forms a friction type release coupling 30 between the two housing parts 10a and 10b and has the purpose of preventing accidental hazardous forces emanating from the kinetic energy of the flywheel 20 to reach the rear housing part 10a and thereby the operator via the handle 11.
Such accidental sudden mechanical interconnection between the flywheel 20 and the forward housing part 10b may be caused by a brake down of the bearing with an abrupt stop of the flywheel 20 as a result. Since the operation order of the power transmission 14 including the flywheel 20 as well as the control of the motor during a screw joint tightening process may be arranged in different ways and is not the object of the invention it is not described in further detail in this specification. However, the basic idea of the flywheel arrangement is to obtain a reaction torgue absorption during a tightening processes to thereby protect the operator from uncomfortable and tiresome reaction forces. This means that the flywheel 20 may attain rather high speed at some instances which means that it contains a high kinetic energy. If, during a high speed seguence of the flywheel 20 something occurs such that the latter is suddenly mechanically interconnected to the housing, for instance a breakdown of the bearings 24, the high kinetic energy of the flywheel 20 would be abruptly transferred to the housing and to the operator via the handle 11.
In Fig. 2 there is illustrated an alternative embodiment of the invention wherein the forward and rear housing parts 10a and 10b are rigidly interconnected, but instead a release coupling 44 is provided between the flywheel supporting bearings 24 and the flywheel 20 itself. This means that if a breakdown should occur in the bearings 24 resulting in a dead stop of the flywheel 20 the friction coupling forming the release coupling 44 would prevent a sudden transfer of kinetic energy from the flywheel 20 to the housing 10a, 10b. Instead, the flywheel 20 would still be allowed to rotate with respect to the housing in the release coupling, although at a higher friction than provided by the supporting bearings 24. In an alternative embodiment a release coupling is instead provided between the flywheel supporting bearings 24 and the housings 10a, 10b. Further, in this embodiment a low friction lining 40 may be provided the on inner wall of the forward housing part 10b. See Fig. 3. As an alternative a low friction lining may be provided on the outer surface of the flywheel 20. Together the low friction lining 40 at the periphery of the flywheel 20 and the release coupling 44 between the bearings 24 and the flywheel 20 will prevent the operator from being exposed to any violent and hazardous forces.
It is to be noted that the invention is not limited to the above described examples but could be freely varied within the scope of the claims. For instance, the friction type release couplings may have alternative designs and may even be replaced by other types of couplings with the same protective characteristics to protect the operator from dangerous forces in case of malfunction of the power wrench. Between the two housing halves 10a and 10b the friction ring arrangement could be replaced by any kind of cam mechanism or even a breakpin dimensioned to withstand reaction forces developed during normal wrench operation but to be sheared off and break the connection between the housing halves in case of a sudden flywheel stop.

Claims

Claims
1. A manually supported power wrench comprising a housing (10a, 10b) with a handle (11) for operator control of the wrench, a rotation motor, a power transmission (14), and an output shaft (15), wherein the power transmission (14) includes a flywheel (20) for reaction torgue absorption, and said flywheel (20) being rotatively supported relative to the housing via one or more bearings (24), c h a r a c t e r i z e d in that a release coupling (30; 44) is provided to prevent any sudden hazardous energy to be transferred to the housing (10a, 10b) and the operator via the handle (11) in case of an occurring
accidental dead stop of the flywheel relative to the housing
(10a, 10b) .
2. Power wrench according to claim 1, wherein the housing (10a, 10b) is divided into two halves, whereof a rear half (10a) supports the handle (11), and a forward half (10b) containing the power
transmission including the flywheel (20) and the bearings (24), wherein said rear housing part (10a) and said forward housing part (10b) are rotatively supported relative each other, and said release coupling (30) is provided between the two housing parts (10a, 10b) .
3. Power wrench according to claim 1, wherein said release coupling (44) is provided between the bearings (24) and the flywheel (20) .
4. Power wrench according to claim 1, wherein said release coupling (44) is provided between the bearings (24) and the housing (10a, 10b).
5. Power wrench according to either of claims 3 or 4, wherein a low friction lining (40) is provided between the flywheel (20) and the housing (10a, 10b) .
PCT/EP2014/054135 2013-03-18 2014-03-04 Safety coupling in a power wrench with a flywheel reaction torque absorber WO2014146894A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1350325-5 2013-03-18
SE1350325 2013-03-18

Publications (1)

Publication Number Publication Date
WO2014146894A1 true WO2014146894A1 (en) 2014-09-25

Family

ID=50231155

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2014/054135 WO2014146894A1 (en) 2013-03-18 2014-03-04 Safety coupling in a power wrench with a flywheel reaction torque absorber

Country Status (1)

Country Link
WO (1) WO2014146894A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110842840A (en) * 2019-12-30 2020-02-28 贵州永昌福科技有限公司 Labor-saving quick wrench

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1286344B (en) * 1963-10-01 1969-01-02 Nittoku Kinzokukogyo Kabushiki Radial roller bearings
DE3735007A1 (en) * 1986-04-18 1989-05-03 Kverneland As Nut-screwing device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1286344B (en) * 1963-10-01 1969-01-02 Nittoku Kinzokukogyo Kabushiki Radial roller bearings
DE3735007A1 (en) * 1986-04-18 1989-05-03 Kverneland As Nut-screwing device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110842840A (en) * 2019-12-30 2020-02-28 贵州永昌福科技有限公司 Labor-saving quick wrench

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