US20100224382A1 - Noise elimination brake for automatic spindle locking mechanism - Google Patents

Noise elimination brake for automatic spindle locking mechanism Download PDF

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Publication number
US20100224382A1
US20100224382A1 US12/667,143 US66714308A US2010224382A1 US 20100224382 A1 US20100224382 A1 US 20100224382A1 US 66714308 A US66714308 A US 66714308A US 2010224382 A1 US2010224382 A1 US 2010224382A1
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US
United States
Prior art keywords
braking member
power tool
rotary power
tool according
output shaft
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.)
Abandoned
Application number
US12/667,143
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English (en)
Inventor
Chi Hoe Leong
Yeo Joanne
Eng Hock Tan
Thomas Mathys
Olivier Zeiter
Daniel Brogli
Andreas Schwieger
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.)
Robert Bosch GmbH
Original Assignee
Individual
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 Individual filed Critical Individual
Assigned to ROBERT BOSCH GMBH reassignment ROBERT BOSCH GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: Schwieger, Andreas, Joanne, Yeo, LEONG, CHI HOE, Tan, Eng Hock, BROGLI, DANIEL, ZEITER, OLIVIER, Mathys, Thomas
Publication of US20100224382A1 publication Critical patent/US20100224382A1/en
Abandoned legal-status Critical Current

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Classifications

    • 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
    • B25F5/001—Gearings, speed selectors, clutches or the like specially adapted for rotary tools

Definitions

  • the present invention relates to rotary power tools and in particular those tools which are configured with an automatic spindle locking mechanism (ASLM).
  • ASLM automatic spindle locking mechanism
  • an ASLM blocks a rotary tool output shaft from rotating in response to an external applied torque, for example resulting from rotation of a tool-holding chuck coupled to the output shaft.
  • the motor shaft and output shaft of a power tool with an ASLM are typically coupled but with some rotational play remaining between the coupling parts.
  • An undesirable consequence of this ASLM configuration arises when the motor shaft slows after the motor has been shut off. Due to its inertia, the output shaft tends to overtake the slowing motor shaft. Relatively speaking, an output shaft that is rotating faster than the motor shaft is in effect attempting to drive the motor shaft, and this leads to engagement of the ASLM.
  • the locking action triggers a reactive force which slows the output shaft and disengages the ASLM.
  • the motor shaft continues to slow down more rapidly until its speed is once again less than the output shaft, and the process repeats. Repeated engagements, disengagements, and reengagements generate an undesirable chattering noise.
  • U.S. Pat. No. 6,311,787 describes several means for counteracting this phenomenon, including an automatic brake and an automatic drag system. These are mediated by output shaft-coupled members which make frictional contact either with housing-coupled members or with motor shaft-coupled members, respectively. In both cases, this serves to slow the rotation of the output shaft relative to the motor shaft so that the frequency of chattering noise is reduced or eliminated altogether.
  • a disadvantage of the prior art solution is that the described structures comprise integral aspects of the design, and they cannot be readily incorporated into an existing rotary power tool without requiring an extensive redesign. What is needed is a simpler and less expensive means of achieving a similar outcome, and particularly a solution that can be implemented on an existing rotary power tool design, thereby requiring no redesign of the power train. It is also advantageous if the invention provides for an intuitive and predictable adjustment, so that the process of optimizing the solution for a particular rotary power tool is simplified.
  • a rotary power tool comprising a motor, a motor shaft driven by the motor, an output shaft coupled to the motor shaft via an ASLM, a housing portion surrounding the output shaft, and a braking member that is non-rotatable relative to the housing portion, wherein the braking member exercises a braking torque on the output shaft whenever it rotates.
  • a preferred and advantageous place for incorporating the braking member is in a position between the two bearing members, since this provides greater consistency to the amount of braking torque exercised by the braking member on the output shaft.
  • the braking member is ring-shaped, thereby allowing the output shaft to position it radially.
  • This shape is also preferable for ensuring consistent and uniform contact with the output shaft and the housing portion via its inner ring surface and outer ring surface, respectively.
  • the braking member is in direct contact with the housing portion to provide means for immobilizing the braking member relative to the rotating output shaft.
  • This contact is advantageously accomplished via an interference it (i.e., a friction fit), since this requires no additional coupling parts, provides some flexibility and tolerance during assembly and minimizes assembly and material costs.
  • the braking torque exercised by the braking member is of sufficient magnitude so that in the absence of an external torque urging the output shaft to rotate, the rotating velocity of the output shaft is always less than or equal to the rotating velocity of the motor shaft.
  • the rotating velocity of the output shaft is always less than or equal to the rotating velocity of the motor shaft.
  • a predictable way of optimizing the forces of friction and adhesion is by adjusting the width of the inner surface of the braking member independently of the overall width by providing this inner surface with a chamfer-shape.
  • An additional way that the braking member can be kept in non-rotational contact with the housing portion is by providing the outer surface of the braking member with a structure that is complimentary with an inner surface of the housing portion.
  • the braking member can be easily fitted to the housing by an interference fit and not require additional members to stabilize the braking member against rotation
  • the braking member is advantageously composed of a flexible, non-metal material, such as felt, plastic, rubber or foam. In comparison with metals, these materials may have lesser material and manufacturing costs.
  • FIG. 1 is a schematic section view of a portion of a rotary tool according to the present invention.
  • FIG. 2 is a partial schematic section view taken along section line A-A of FIG. 1 .
  • FIG. 3 is a perspective view of a braking member according to a first embodiment of the invention.
  • FIG. 4 is a perspective view of a braking member according to a second embodiment of the invention.
  • FIG. 1 A portion of a rotary power tool and particularly a drill/driver according to the present invention is illustrated in schematic form in FIG. 1 .
  • the power source for such tools is typically either AC current or a DC battery.
  • a motor 12 Positioned within the housing 10 of the rotary power tool are a motor 12 driven by this power source and its associated motor shaft 14 .
  • a transmission 16 modulates the speed and torque conveyed by the motor shaft 14 to downstream elements in the power train.
  • ASLM automatic shaft locking mechanism
  • ASLM's are well known in the art, and the details of how they operate will not be described in detail in the present description.
  • readers are referred instead to U.S. Pat. No. 6,311,787 and U.S. Patent Publication No. 2006/0131043 A1 which are hereby incorporated by reference.
  • the transmission 16 may not necessarily be discrete from the ASLM 18 . That is, there may be components that function as both part of the transmission 16 and the ASLM 18 .
  • the output shaft 20 Downstream from the ASLM 18 is an output shaft 20 .
  • the output shaft 20 may interact directly with the ASLM 18 or it may be coupled to one or more other elements in between.
  • a housing portion 28 comprises the portion of housing 10 that is coaxial with and surrounds the output shaft 20 .
  • the output shaft 20 is coupled with this housing portion 28 via two ring-shaped ball bearings 22 and 24 which serve to stabilize the shaft.
  • an output interface 26 At the end of the output shaft 20 is an output interface 26 for attaching a tool holder such as a drill chuck or the like. Alternatively tools can be attached directly to the output shaft 20 itself.
  • a braking member comprising a felt ring 30 is positioned between the two ball bearings 22 and 24 . It surrounds the output shaft 20 and preferably is secured by an interference (friction) fit with housing portion 28 . The resulting friction between the felt ring 30 and the housing portion 28 is much greater than the friction between it and the output shaft 20 . As a result, the braking member will not rotate relative to the housing portion 28 when the output shaft 20 is rotating at typical operating speeds in the range of 400-1400 RPM. The friction can be of sufficient magnitude so that no means for maintaining the position of the braking member in the axial direction are necessary.
  • the bearings 22 and 24 would serve to confine the braking member to the generally appropriate axial location around the output shaft 20 , which is preferably at any axial point that is between the two bearings. Any friction resulting from contact of the braking member with the side of the ring-shaped ball bearing 22 is negligible in comparison to the frictional force exerted on the output shaft 20 .
  • the braking member is positioned in the space between the bearings 22 and 24 , but it may alternatively be positioned outside of them provided there is sufficient axial space to accommodate the braking member and there is no interference with other structures.
  • the felt ring 30 is seen in isolation in FIG. 3 and is characterized by an inner diameter 32 , an outer diameter 34 , and a thickness 36 .
  • the inner diameter 32 and the outer diameter 34 are chosen so as to satisfy the preferred frictional conditions discussed above. However, particular care has been taken to adjust the inner diameter 34 so as to control the frictional force between the inner surface 38 of the felt ring 30 and the output shaft 20 . In a preferred scenario, this braking torque is just exactly enough so that the down-coasting velocity of the output shaft 20 is slowed to a rate exactly equal to that of the motor shaft 14 . When this condition is satisfied, there is no engagement of the ASLM 18 when the power is cut to the motor.
  • this preferred scenario does not define the preferred embodiment, since with repeated use of the tool, there is wear on the felt ring 30 , and this may alter the amount of friction between the braking member and the output shaft 20 .
  • a bearing that is designed to minimize friction will exert some frictional force on a shaft that it is supporting, thereby exerting a theoretical braking torque on the shaft.
  • the braking member described here is not intended to provide support for the output shaft 20 . It is intended to be of inexpensive construction, and is designed not for minimizing friction, but for introducing friction.
  • the amount of braking torque it exerts is preferably adjustable and the alternative embodiment described below provides one manner of achieving precision in controlling this parameter during design of the tool.
  • a second embodiment for a braking member, comprising an elastic ring 40 made of soft resilient material is shown in isolation in FIG. 4 .
  • the elastic material may be a rubber, such as nitrile butadiene rubber (NBR), a plastic, such as acetal polyoxymethelene (POM), or a cellular urethane foam, such as Poron® (a registered U.S. trademark of Rogers Corporation), each of which could have the appropriate combination of elasticity and strength to serve as the braking member.
  • NBR nitrile butadiene rubber
  • POM acetal polyoxymethelene
  • Poron® a registered U.S. trademark of Rogers Corporation
  • the outer surface 41 of the elastic ring 40 is configured to have what can be generally characterized as protrusions 42 and recesses 44 .
  • these features are intended to cooperate with complementary recesses 46 and protrusions 48 respectively that may be present on the inner surface 49 of the housing portion 28 (see FIG. 2 ). Such cooperation would potentially lessen the extent to which a friction fit between the elastic ring 40 and the housing portion 28 is necessary.
  • Alternative means for securing the braking member against rotation include configuring the housing portion 28 with pin-like structures (not shown) that would puncture and deeply penetrate the braking member during the housing assembly process.
  • a braking member without cooperating features can be used (see FIG. 3 ) since the braking member is composed of compliant material.
  • Protrusions and recesses could also be provided on the felt ring 30 . However this may be more complicated or costly from a manufacturing standpoint versus an elastic ring 40 which can be made from a variety of materials that lend themselves well to injection molding. Hence when more complicated surface contours are desired, the braking member is preferably manufactured from moldable materials.
  • Changing the contact area with the output shaft 20 by varying the inner surface 50 of elastic ring 40 is one way to optimize the amount of braking provided by the brake member.
  • the inner surface 50 of the elastic member 40 can be chamfered to create a chamfered surface 52 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)
US12/667,143 2007-06-29 2008-05-30 Noise elimination brake for automatic spindle locking mechanism Abandoned US20100224382A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP07111436.7 2007-06-29
EP07111436A EP2008773B1 (fr) 2007-06-29 2007-06-29 Frein éliminant le bruit pour mécanisme de blocage automatique de broche
PCT/EP2008/056658 WO2009003774A1 (fr) 2007-06-29 2008-05-30 Frein à élimination de bruit pour mécanisme de blocage de broche automatique

Publications (1)

Publication Number Publication Date
US20100224382A1 true US20100224382A1 (en) 2010-09-09

Family

ID=38740301

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/667,143 Abandoned US20100224382A1 (en) 2007-06-29 2008-05-30 Noise elimination brake for automatic spindle locking mechanism

Country Status (5)

Country Link
US (1) US20100224382A1 (fr)
EP (1) EP2008773B1 (fr)
CN (1) CN101730612B (fr)
DE (1) DE602007012222D1 (fr)
WO (1) WO2009003774A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100084930A1 (en) * 2008-10-07 2010-04-08 Yong Joo Kim Spindle motor
US10464201B2 (en) 2011-07-29 2019-11-05 Black & Decker Inc. Multispeed power tool
USD989508S1 (en) * 2019-03-28 2023-06-20 San Jamar, Inc. Roll towel dispenser lockout

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009054929B4 (de) 2009-12-18 2022-08-11 Robert Bosch Gmbh Handwerkzeugmaschinenvorrichtung
DE102011005553A1 (de) * 2010-10-15 2012-04-19 Robert Bosch Gmbh Handgeführtes Elektrowerkzeug mit einer Spindellockvorrichtung
DE102013212193A1 (de) * 2013-06-26 2014-12-31 Robert Bosch Gmbh Handwerkzeugmaschine mit einer Spindellockvorrichtung
WO2022192201A1 (fr) * 2021-03-08 2022-09-15 Milwakuee Electric Tool Corporation Verrouillage de broche pour outil électrique

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904322A (en) * 1932-03-26 1933-04-18 Independent Pneumatic Tool Co Stud setting tool
US3419087A (en) * 1967-03-30 1968-12-31 Chicago Pneumatic Tool Co Torque controlled electric nut-runner with solenoid brake
US4063625A (en) * 1975-02-11 1977-12-20 Atlas Copco Aktiebolag Improved screw or nut runner
US4947939A (en) * 1989-11-20 1990-08-14 Wonder Hung Structure of motorized screw bolt driving tool
US5732805A (en) * 1995-08-03 1998-03-31 Nakamura; Daijiro Lock device of output shaft
US6128984A (en) * 1995-09-25 2000-10-10 Haupt; Chett D. Micro-torque limiting, shock limiting tool and subassembly
US6311787B1 (en) * 2000-04-18 2001-11-06 Black & Decker Inc. Power driven rotary device
US6454020B1 (en) * 2002-01-29 2002-09-24 Jenn Feng Industrial Co., Ltd. Locking device for output shaft of electric tools
US6497316B1 (en) * 2000-01-18 2002-12-24 Mobiletron Electronics Co., Ltd. Powered, unidirectional output controlling apparatus
US20060024141A1 (en) * 2004-07-30 2006-02-02 Hilti Aktiengesellschaft Power tool with an intermittent angular torque pulse
US7063201B2 (en) * 2001-11-27 2006-06-20 Milwaukee Electric Tool Corporation Power tool and spindle lock system
US20060131043A1 (en) * 2004-11-16 2006-06-22 Olivier Zeiter Slaving and blocking device
US20060243469A1 (en) * 2003-06-11 2006-11-02 Webster Craig D Handwheel-operated device

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904322A (en) * 1932-03-26 1933-04-18 Independent Pneumatic Tool Co Stud setting tool
US3419087A (en) * 1967-03-30 1968-12-31 Chicago Pneumatic Tool Co Torque controlled electric nut-runner with solenoid brake
US4063625A (en) * 1975-02-11 1977-12-20 Atlas Copco Aktiebolag Improved screw or nut runner
US4947939A (en) * 1989-11-20 1990-08-14 Wonder Hung Structure of motorized screw bolt driving tool
US5732805A (en) * 1995-08-03 1998-03-31 Nakamura; Daijiro Lock device of output shaft
US6128984A (en) * 1995-09-25 2000-10-10 Haupt; Chett D. Micro-torque limiting, shock limiting tool and subassembly
US6497316B1 (en) * 2000-01-18 2002-12-24 Mobiletron Electronics Co., Ltd. Powered, unidirectional output controlling apparatus
US6311787B1 (en) * 2000-04-18 2001-11-06 Black & Decker Inc. Power driven rotary device
US7063201B2 (en) * 2001-11-27 2006-06-20 Milwaukee Electric Tool Corporation Power tool and spindle lock system
US6454020B1 (en) * 2002-01-29 2002-09-24 Jenn Feng Industrial Co., Ltd. Locking device for output shaft of electric tools
US20060243469A1 (en) * 2003-06-11 2006-11-02 Webster Craig D Handwheel-operated device
US20060024141A1 (en) * 2004-07-30 2006-02-02 Hilti Aktiengesellschaft Power tool with an intermittent angular torque pulse
US20060131043A1 (en) * 2004-11-16 2006-06-22 Olivier Zeiter Slaving and blocking device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100084930A1 (en) * 2008-10-07 2010-04-08 Yong Joo Kim Spindle motor
US10464201B2 (en) 2011-07-29 2019-11-05 Black & Decker Inc. Multispeed power tool
US11491632B2 (en) 2011-07-29 2022-11-08 Black & Decker Inc. Multispeed power tool
USD989508S1 (en) * 2019-03-28 2023-06-20 San Jamar, Inc. Roll towel dispenser lockout

Also Published As

Publication number Publication date
EP2008773A1 (fr) 2008-12-31
CN101730612B (zh) 2013-01-23
EP2008773B1 (fr) 2011-01-26
WO2009003774A1 (fr) 2009-01-08
DE602007012222D1 (de) 2011-03-10
CN101730612A (zh) 2010-06-09

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AS Assignment

Owner name: ROBERT BOSCH GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LEONG, CHI HOE;JOANNE, YEO;TAN, ENG HOCK;AND OTHERS;SIGNING DATES FROM 20100212 TO 20100414;REEL/FRAME:024497/0990

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION