EP3856476A1 - Système d'actionnement pour un élément de freinage - Google Patents

Système d'actionnement pour un élément de freinage

Info

Publication number
EP3856476A1
EP3856476A1 EP19773413.0A EP19773413A EP3856476A1 EP 3856476 A1 EP3856476 A1 EP 3856476A1 EP 19773413 A EP19773413 A EP 19773413A EP 3856476 A1 EP3856476 A1 EP 3856476A1
Authority
EP
European Patent Office
Prior art keywords
brake device
claw coupling
safety brake
claw
actuator element
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.)
Pending
Application number
EP19773413.0A
Other languages
German (de)
English (en)
Inventor
Daniel Dennis
Florian Esenwein
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
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP3856476A1 publication Critical patent/EP3856476A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B5/00—Sawing machines working with circular or cylindrical saw blades; Components or equipment therefor
    • B27B5/29—Details; Component parts; Accessories
    • B27B5/38—Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
    • B27G19/00—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws
    • B27G19/02—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws for circular saws
    • B27G19/04—Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws for circular saws for manually-operated power-driven circular saws

Definitions

  • the invention relates to an actuator system for a braking element.
  • a handheld power tool in particular a hand-held circular saw with a machining tool designed as a saw blade, with a safety brake device for braking the
  • Actuator element triggers the safety brake device as soon as an approach to human skin or a contact of the saw blade with human skin is detected.
  • the safety brake device is designed as a dog clutch with a first dog clutch part and a second dog clutch part.
  • a positive connection is advantageously established, as a result of which braking takes place quickly and safely.
  • a particularly fast-reacting actuator element is to be made available for triggering the claw coupling in order to avoid injuries during an intervention in the circular saw blade or to keep them as small as possible. This is achieved in that the actuator element actuates the safety brake device directly.
  • the actuator element is designed as a lifting unit which actively moves at least one claw coupling part of the claw coupling.
  • a lifting unit is understood to mean one or more elements which, when an activation energy, preferably an electrical current, is applied, are able to expand axially suddenly and at least one
  • the actuator element is designed as a “shape memory alloy” (SMA) element which actively moves at least one claw coupling part of the claw coupling.
  • SMA shape memory alloy
  • Figure 1 a hand tool according to the invention in
  • Figure 2 an embodiment of an actuator element in a schematic
  • Figure 3 another embodiment of an actuator element in
  • FIG. 4 a further embodiment of an actuator element in a schematic representation
  • Figure 5 another embodiment of an actuator element in
  • Figure 6 another embodiment of an actuator element in
  • Figure 7 another embodiment of an actuator element in
  • Figure 8 another embodiment of an actuator element in
  • Figure 9 another embodiment of an actuator element in
  • Figure 1 shows a handheld power tool 10, which is designed as a hand-held circular saw, and the hand-held circular saw 10 in a sectional view.
  • the circular saw 10 comprises a first housing 12, which as
  • the circular saw 10 has a handle 11 and a base plate 13 for guiding the
  • the motor housing 12 receives an electric motor drive 16.
  • the electric motor drive 16 drives via a motor shaft 18 and one Machining shaft 20 rotates a machining tool 22 during an operation.
  • the machining tool 22 is designed as a saw blade, in particular as a circular saw blade.
  • a saw blade cover 24 protects against contact with the saw blade 22 and against workpiece chips of a workpiece ejected by the saw blade 22.
  • a first gearwheel 25 is arranged on the motor shaft 18 and meshes with a second gearwheel 26 seated on the machining shaft 20.
  • the second gear 26 has the function of a safety clutch.
  • the first gear 25 and the safety clutch 26 form a first gear stage.
  • the safety clutch 26 protects the electric motor drive 16 from damage which can be caused by the machining tool being blocked.
  • the safety clutch has the function of keeping the masses to be braked as low as possible during sudden braking by decoupling the drive train after the safety clutch. that from
  • the safety clutch 26 disconnects in the event of an overload, i.e. when a limit of the transmitted torque is exceeded, the motor shaft 18 of the
  • the limit of the torque to be transmitted is at least 5 Nm, maximum 12 Nm, but preferably 10 Nm.
  • a safety brake device 30 is provided for braking the saw blade 18 as soon as a contact or approach to a human body part, such as a finger, is detected with the saw blade 22.
  • An actuator unit 60 is provided to actuate the safety brake device 30.
  • the actuator unit 60 actuates a component of the
  • a brake system 30 is designed as a dog clutch, as shown in FIG. 2.
  • a first part 32 of the dog clutch 30 is arranged on the machining shaft 20.
  • the first coupling part 32 is connected to the machining shaft 20 in a rotationally fixed manner.
  • a second part 34 of the dog clutch 30 is designed as a dog clutch, as shown in FIG. 2.
  • Claw coupling 30 is arranged in the motor housing of the hand-held circular saw 10.
  • the second part 34 of the dog clutch 30 is designed to be non-rotatable with respect to the motor housing 12, but is axially displaceable. During a braking operation, the second part 34 of the dog clutch 30 is moved axially in the direction R into the first part 32 of the dog clutch 30. However, it is also possible to move both coupling parts 32, 34 axially towards the other, whereby the coupling can be closed. The claws interlock and create a positive connection. Thus, the movement of the machining shaft 20 is stopped.
  • the actuator unit 60 is designed as a lifting unit. If a braking operation is to be initiated, the lifting unit 60 is energized as soon as a human touches or approaches
  • the lifting unit 60 expands spatially in the direction R and moves the second part 34 of the dog clutch 30 axially in the direction R into the first part 32 of the dog clutch 30 connected to the machining shaft 20.
  • the claws interlock and create a positive connection.
  • the spatial expansion of the lifting unit 60 takes place in a time of less than 5 ms, in particular less than 1.5 ms.
  • the machining shaft 20 is blocked in a time of less than 10 ms, in particular less than 5 ms. This is the time that passes from the energization of the actuator 60 until the machining shaft 20 comes to a standstill.
  • the two claw coupling parts 32, 34 are pressed apart by a spring 62.
  • the spring 62 is between the first part 32 and the second part 34 of the
  • Claw clutch 30 arranged.
  • two or more springs can also be used are used. If the lifting unit 60 is no longer energized, it moves back to its original length. So that the second part 34 of the
  • the actuator element 60 is designed as a shape memory alloy (SMA) cable.
  • SMA shape memory alloy
  • the SMA cable 60 is fixed to the via two connection points 61a, 61b
  • the SMA cable 60 is electrically insulated from the second part 34 of the claw coupling 30.
  • the SMA cable 60 can also be designed as an multi-strand actuator element 60.
  • Several SMA cables as actuators can be distributed symmetrically over a circumference of the second part 34 of the claw coupling 30.
  • the second part 34 of the claw coupling 30 is rigidly connected to the housing of the circular saw 10.
  • the first part 32 of the dog clutch 30 is arranged axially displaceably on the machining shaft 20.
  • Behind the first claw coupling part 32 there is a disk 64 which is in contact with the first part 32 of the claw coupling 30 via a slide bearing 66.
  • the disc 64 is rotatably stable, axially displaceable with the housing of the circular saw 10 connected.
  • the disk 64 is moved in the direction R of the safety brake device 30 via an actuator element 60 designed as a lifting unit.
  • the disk 64 takes the first part 32 of the claw coupling 30 in the direction R and presses the first part 32 of the claw coupling 30 into the second part 34 of the claw coupling 30 which is fixedly connected to the housing.
  • the claws interlock and the movement of the machining shaft 20 becomes stopped suddenly.
  • a spring 62 is arranged between the first part 32 and the second part 34 of the dog clutch 30. In order to release the safety brake system 30 again, the two claw coupling parts 32, 34 are pressed apart by the spring 62.
  • the actuator element 60 in FIG. 5 is designed as an SMA wire, which pulls the first part 32 of the claw coupling 30 into the second part of the claw coupling 30 via a disk 64.
  • FIG. 6 shows an actuator element 60 which is designed as an SMA cable.
  • the actuator element 60 is connected to a disk 64, which is rotatably connected to the machining shaft 20 via a ball bearing.
  • the disk 64 is either provided with a lubricious coating or there is a slide bearing between the disk 64 and the first part 32 of the dog clutch 30, which allows low-friction sliding between the disk 64 and the first part 32 of the dog clutch 30.
  • the second claw coupling part 34 has no mechanical connection to the machining shaft 34 and is axially displaceable via grooves in the housing and is secured against rotation.
  • the first part 34 of the dog clutch 30 is thus moved into the second part of the dog clutch 32, which is non-rotatably connected to the shaft 20.
  • the claws interlock and the movement of the machining shaft 20 is stopped suddenly.
  • the first coupling element 32 is pressed into the second coupling element 34 via a preloaded spring 62. If the spring is pretensioned, the first coupling element 32 is held in the starting position against the spring force by means of two grinding pins 63. On the first part 32 of the coupling 30 there is a groove 70 in which the grinding pin 62 engages.
  • the actuator element 60 is designed as a piezo stack that extends axially.
  • the stroke of the actuator element 60 is increased via a rotatably mounted lever arm 72.
  • the lever arm 72 is designed such that the ratio between A and B corresponds to at least 1: 5, preferably 1:10.
  • Claw coupling part 34 moves. This blocks the machining shaft 20.
  • the first coupling element 32 is moved into the second coupling element 34 via a prestressed spring 62. If the spring is preloaded, the first coupling element 32 is held in the starting position against the spring force by means of two grinding pins 60. On the first part 32 of the
  • Coupling 30 is a groove 70 in which the grinding pin 63 engages.
  • the actuator element 60 is designed here as one or more SMA cables.
  • the actuator element 60 is arranged as a lifting element on the machining shaft 22.
  • One or more actuator elements are located on the machining shaft 22 between the first claw element 32 and a disk 64.
  • the current to the actuator element 60 is transmitted via a slip ring 74.
  • slip rings are worked directly into the disk 64.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Braking Arrangements (AREA)

Abstract

L'invention concerne un dispositif de freinage de sécurité (30) pour freiner une lame (22) d'une scie circulaire portative (10), comprenant un premier élément de freinage (32), le premier élément de freinage (32) étant monté solidaire en rotation sur un arbre d'usinage (20) de la scie circulaire portative (10), et un deuxième élément de freinage (34), le deuxième élément de freinage (34) étant bloqué en rotation sur un boîtier (12) de la scie circulaire portative (10). Selon l'invention, un élément actionneur (60) déclenche le dispositif de freinage de sécurité (30) dès la détection du fait que la peau humaine s'approche de la lame de scie (22) ou que cette dernière entre en contact avec la peau humaine.
EP19773413.0A 2018-09-27 2019-09-20 Système d'actionnement pour un élément de freinage Pending EP3856476A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102018216552.1A DE102018216552A1 (de) 2018-09-27 2018-09-27 Aktorik für ein Bremselement
PCT/EP2019/075287 WO2020064528A1 (fr) 2018-09-27 2019-09-20 Système d'actionnement pour un élément de freinage

Publications (1)

Publication Number Publication Date
EP3856476A1 true EP3856476A1 (fr) 2021-08-04

Family

ID=68051792

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19773413.0A Pending EP3856476A1 (fr) 2018-09-27 2019-09-20 Système d'actionnement pour un élément de freinage

Country Status (4)

Country Link
EP (1) EP3856476A1 (fr)
CN (1) CN112789145B (fr)
DE (1) DE102018216552A1 (fr)
WO (1) WO2020064528A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019208438A1 (de) * 2019-06-11 2020-12-17 Festool Gmbh Werkzeugvorrichtung und Verfahren

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1327118A (fr) * 1962-03-30 1963-05-17 Constr Telephoniques Mécanisme de verrouillage d'un arbre rotatif
US3785230A (en) * 1972-11-08 1974-01-15 Lokey Tool Inc Automatic safety brake for rotary blade equipment
JPS60213275A (ja) * 1984-04-07 1985-10-25 Shoketsu Kinzoku Kogyo Co Ltd ブレ−キ装置
JPH03117380A (ja) * 1989-09-28 1991-05-20 Okuma Mach Works Ltd 回転機
JP3117380B2 (ja) * 1995-02-13 2000-12-11 三菱重工業株式会社 泥水式トンネル掘削機
US7905786B2 (en) * 2007-02-20 2011-03-15 Robert Bosch Gmbh Decoupling mechanism for power tools
RU2517619C2 (ru) * 2008-11-17 2014-05-27 Литенс Аутомотив Партнершип Механизм сцепления со спиральной пружиной, содержащий исполнительный механизм, приводящий спиральную пружину в зацепление с поверхностью сцепления
WO2010059786A1 (fr) * 2008-11-19 2010-05-27 Power Tool Institute Mécanismes de sécurité pour machines-outils
DE102008054694A1 (de) * 2008-12-16 2010-06-17 Robert Bosch Gmbh Werkzeugnotbremsvorrichtung
DE102017201493A1 (de) * 2017-01-31 2018-08-02 Robert Bosch Gmbh Kreissäge, insbesondere Handkreissäge

Also Published As

Publication number Publication date
CN112789145B (zh) 2024-04-26
CN112789145A (zh) 2021-05-11
WO2020064528A1 (fr) 2020-04-02
DE102018216552A1 (de) 2020-04-02

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