GB2395456A - Hand held machine tool - Google Patents

Hand held machine tool Download PDF

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Publication number
GB2395456A
GB2395456A GB0326839A GB0326839A GB2395456A GB 2395456 A GB2395456 A GB 2395456A GB 0326839 A GB0326839 A GB 0326839A GB 0326839 A GB0326839 A GB 0326839A GB 2395456 A GB2395456 A GB 2395456A
Authority
GB
Grant status
Application
Patent type
Prior art keywords
tool
ring
part
striker
held
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.)
Granted
Application number
GB0326839A
Other versions
GB2395456B (en )
GB0326839D0 (en )
Inventor
Otto Baumann
Dietmar Saur
Andre Ullrich
Michael Weiss
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

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25DPERCUSSIVE TOOLS
    • B25D11/00Portable percussive tools with electromotor or other motor drive
    • B25D11/005Arrangements for adjusting the stroke of the impulse member or for stopping the impact action when the tool is lifted from the working surface
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25DPERCUSSIVE TOOLS
    • B25D2250/00General details of portable percussive tools; Components used in portable percussive tools
    • B25D2250/191Ram catchers for stopping the ram when entering idling mode

Abstract

A hand-held machine tool in the form, in particular, of a rotary or percussion hammer has a motor-driven percussion mechanism (12), in which a striker (14) is connected preferably via an air cushion to a reciprocating drive member and delivers its energy via a striking element (18), guided axially movably in a guide part (19), to a tool (17) guided in a tool holder (16). The striker (14) is assigned a striker-catching device (32) which catches the striker in the idle position and has a ring (37) contained in a receptacle (36), through the inside of which ring a shoulder (28) of the striker (14) can extend. The receptacle (36) is realised by means of at least one deep-drawn part, in particular by means of at least one deepdrawn sleeve (38, 39).

Description

Hand-held machine tool, in particular rotary or percussion hammer Prior

art

The invention takes as its starting point a hand-held machine tool, in particular a rotary or percussion hammer, of the generic type defined in the precharacterising clause of Claim 1.

In a known hand-held machine tool of this type (DE 33 29 005 Al), the guide part for the axially movably guided striking element comprises a special guide element.

Normally, the striker is assigned a striker-catching device 15 which catches the striker in the idle position. The striker-catching device has a holder with a receptacle, in which a ring, in particular an elastic ring, e.g. O-ring, is contained, through the inside of which a shoulder of the striker can extend in the idle position. To realise the 20 receptacle which accommodates the ring, a groove is made in an appropriate holder by machining, e.g. by turning. It is also known to form the holder from machined sleeves or suchlike parts, in order to realise an appropriate mounting for the ring, in particular O-ring. This is costly.

In contrast, the hand-held machine tool according to the invention with the features in Claim 1 has the advantage that by realising the receptacle by means of at least one deep-drawn part a great cost saving is obtained coupled 30 with a very high dimensional and geometrical accuracy.

Through the measures set out in the further claims, advantageous developments and improvements of the hand-held

machine tool specified in Claim 1 are possible. If, in accordance with Claim 7, the holder has two deep-drawn sleeves, these two sleeves can be realised at low cost and with a saving of time as a preassembly. Furthermore, owing 5 to the fact that the components can be produced with thin walls, a reduction in weight can be achieved coupled with a high geometrical and dimensional accuracy.

Drawing An exemplary embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. The drawing shows a schematic longitudinal

section of part of a hand-held machine tool in the form of 15 a rotary hammer with the tool merely indicated in dashed lines, the percussive drilling position being illustrated above the longitudinal centre axis and the idle position below it.

20 Description of the exemplary embodiments

The drawing shows part of a hand-held machine tool 10 which is in the form of a rotary or percussion hammer and has a housing 11 with an electric drive motor (not shown in 25 further detail), gearing and a percussion mechanism 12 which is arranged at least partly inside a guide tube 13.

The percussion mechanism 12 has a striker 14 which is guided in a sealed and sliding manner in the guide tube 13 and furthermore a drive member (not shown) which is 30 likewise guided in a sealed and sliding manner in the guide tube 13 and is in the form of a piston for example.

Arranged in the wall of the guide tube 13 are bores 15 which serve as air ducts and can be opened and closed in

front of the striker 14 in a known manner. In the region, not visible, between the striker 14 and the drive member, an air cushion is generated under the influence of the reciprocating drive member and sets the striker 14 in an 5 oscillating motion, the striker 14 delivering its energy in the axial direction to a tool 17 guided in a tool holder 16. This takes place in a known manner via an approximately bolt-shaped striking element 18 which is arranged between the striker 14 and the tool 17 and is guided in an axially 10 movable manner in a guide part 19. Each impingement of the striker 14 on the striking element 18 results in the impact energy being transmitted to the tool 17 inserted in the tool holder 16.

15 The drawing shows, above the longitudinal centre axis 20 of the handheld machine tool 10, the percussive drilling position, in which the tool 17 presses axially against the striking element 18 by way of its end which is on the right in the drawing. The position illustrated below the 20 longitudinal centre axis 20 is the idle position, in which the tool 17 is not pressed on.

The guide tube 13 runs inside a cylindrical sleeve 30 which continues in the drawing, by way of a shoulder 31 with a 25 radial step, in one piece as far as the tool holder 16.

Held inside the sleeve 30 is a striker-catching device 32 which is fixed in one axial direction by means of a ring 33, e.g. a snap ring, and is supported in the other axial direction, axially with respect to the tool holder 16, via 30 a damping ring 34. The striker-catching device 32 has a holder 35 with a receptacle 36 which is open towards the longitudinal centre axis 20 and is in the form of an annular groove, in which a ring 37, in particular an O

ring, is accommodated. This striker-catching device 32 - serves to obtain better idle behaviour. In the idle position of the striker 14 shown below the longitudinal centre axis 20, the ring 37 ensures that there is a radial 5 catching force acting on the striker 14, which causes the striker 14 to remain in the idle position when the tool 17 is not moved in. The has the advantage of a more pleasant noise, less vibration and in addition results in an increase in the durability and service life.

The guide part 19 accommodating and guiding the bolt-shaped striking element 18 is centred in the sleeve 30 and held in an axially immovable manner. The striking element 18 is able to move slightly axially inside the guide part 19, in 15 order that as far as possible the entire impact energy is utilised. It is advantageous for the striking element 18 to have a circumferential sealing action together with the associated 20 inner circumferential surface 22 of the guide part 19, so that the striking element 18 can perform a sealing function too. On its circumference, the striking element 18 has a sealing ring 23, e.g. an O- ring. The inner circumferential surface 22 of the guide part 19 is designed as a sealing 25 surface, so that the guide part 19 serves not only for guiding the striking element 18 but at the same time also as a sealing diameter.

At an end situated on the right in the drawing, the guide 30 part 19 has a radially inwardly directed annular edge 24 which acts as an axial limit stop for the striking element 18 when moving towards the right in the drawing. The other end of the guide part 19 is axially supported on the

shoulder 31. The sleeve 30 forms a one-piece component with the shoulder 31 and the tool holder 16. The guide part 19 is accommodated and centred in the sleeve 30. Arranged between the guide part 19 and the holder 35 of the striker-

5 catching device 32 is the damping ring 34. The guide part 19 is thus axially fixed in the sleeve 30 by way of the axial fixing of the holder 35 by means of the ring 33.

The striker 14 has a shoulder 28, projecting axially 10 towards the left in the drawing, which is of smaller diameter than the other part guided in the guide tube 13 by means of a sealing ring 9 and at the free end has a head part 29 which is at least slightly larger in diameter and merges into a frustoconical surface directed towards the 15 tool holder 16. The inside diameter of the ring 37, in particular O-ring, is dimensioned in relation to the head part 29 and adjoining shoulder 28 such that the head part 29 of the striker 14 can extend through the inside of the ring 37 while deforming it, until the shoulder 28 which is 20 at least slightly smaller in diameter is in the region of the inside of the ring 37. In this way, the striker 14 in the idle position shown below the longitudinal centre axis 20 is caught by the ring 37 by means of a radial catching force. This causes the striker 14 to remain in the idle 25 position when the tool 17 is not moved in. The hand-held machine tool thus has a more pleasant noise and less vibration. In addition, the durability is increased.

In known hand-held machine tools 10, the receptacle 36 for 30 the ring 37 is formed by machining appropriate components or by previously machined components. This kind of operation or use of components produced by machining is costly. Instead of this, in the hand-held machine tool 10

shown, the receptacle 36 is realised by means of a deep-

drawn part, in the exemplary embodiment shown by means of two deep-drawn sleeves 38, 39. Here, the receptacle 36 is constructed as a substantially radially inwardly open 5 annular groove realised between the two deepdrawn sleeves 38, 39. In this form, the holder 35 of the striker-catching device 32 thus has a plurality of parts. In another exemplary embodiment (not shown), instead of this there is provided a one-part holder 35 which is likewise constructed 10 as a deep-drawn part and thus has integral sections forming at least part of the receptacle 36. Each deep-drawn sleeve 38, 39 has at one end a radially inwardly directed flange 40 and 41, respectively, each of which forms an annular flank of the receptacle 36, in particular annular groove.

15 At the other opposite end, each deep-drawn sleeve 38, 39 has a radially outwardly directed flange 42 and 43, respectively, which serves for axial support and/or radial holding inside the sleeve 30. The two deep-drawn sleeves 38, 39 are pushed axially into each other in such a way 20 that their respective cylindrical sleeve sections fit together in a substantially precise-fitting manner, so that the outer sleeve 38 accommodates the inner sleeve 39 in a substantially precise-fitting and clearance-free manner.

The radially inwardly directed flanges 40, 41 are axially 25 spaced from each other, forming the annular flanks of the receptacle 36, in particular annular groove, on both sides.

The spacing of the flanges 40, 41 is dimensioned such that the ring 37, in particular O-ring, is securely accommodated therebetween. The other two flanges 42, 43 of both sleeves 30 38, 39 lie against each other and are axially supported on the guide part 19 in the direction facing towards the tool holder 16 via the damping ring 34. In opposite axial direction to this, the holder 35 thus formed is axially

fixed on the sleeve 30 by means of the ring 33, e.g. snap ring. Such a construction of the holder 35 from two deep-drawn 5 sleeves 38, 39 results in a considerable reduction of the production costs, since at least one deep-drawn sleeve or two deep-drawn sleeves 38, 39 can be produced at considerably lower cost than is possible when producing the receptacle 36 by machining. When using two deep-drawn 10 sleeves 38, 39, these can each be realised at low cost and with a saving of time as a preassembly. In addition, owing to the fact that these sleeve components can be produced with thin walls, a weight reduction can be achieved coupled with a high geometrical and dimensional accuracy.

In percussive drilling operation, corresponding to the position above the longitudinal centre axis 20, as a result of being pressed onto the workpiece the tool 17 presses the striking element 18 onto the annular edge 24 of the guide 20 part 19, which forms an axial stop, the guide part 19 being supported by means of the ring 33, via the damping ring 34 and the two sleeves 38, 39, on the sleeve 30 and thus on the tool holder 16. Here, the striker 14 is situated in the percussive drilling position, with its head part not coming 25 into engagement with the ring 37.

If the tool 17 is no longer pressed onto the workpiece, the tool 17 no longer presses the striking element 18 against the annular edge 24. On this transition to idle running, 30 the striker 14 moves into the idle position shown below the longitudinal centre axis 20, in which its head part 29 and shoulder 28 extend through the inside of the ring 37. As a

result, the striker 14 is caught in this idle position, in which it remains when the tool 17 is no longer pressed on.

Claims (17)

  1. Claims 1. Hand-held machine tool, in particular rotary or 5 percussion
    hammer, with a motor-driven percussion mechanism (12), in which a striker (14) is connected preferably via an air cushion to a reciprocating drive member and delivers its energy via a striking element (18), guided axially movably in a guide part (19), to 10 a tool (17) guided in a tool holder (16), the striker (14) being assigned a striker-catching device (32) which catches the striker in the idle position and has a ring (37) contained in a receptacle (36), through the inside of which ring a shoulder (28) of the 15 striker (14) can extend, characterized in that the receptacle (36) is realised by means of at least one deep-drawn part.
  2. 2. Hand-held machine tool according to Claim 1, 20 characterized in that the receptacle (36) is constructed as an approximately radially inwardly open annular groove which is realised by at least one deep drawn part.
    25
  3. 3. Hand-held machine tool according to Claim 1 or 2, characterized in that the striker-catching device (32) has a holder (35) with one or more parts which is constructed as a deep-drawn part and thus has integral sections which form at least part of the receptacle 30 (36).
  4. 4. Hand-held machine tool according to Claim 3, characterized in that the holder (35) with one or more parts has at least one deep-drawn sleeve (38, 39).
  5. 5 5. Hand-held machine tool according to Claim 4, characterized in that the at least one deep-drawn sleeve (38,39) has at one end at least one radially inwardly directed flange (40,41) which forms an annular flank of the receptacle (36), in particular 10 annular groove.
  6. 6. Hand-held machine tool according to Claim 4 or 5, characterized in that the at least one deep-drawn sleeve (38,39) has at the other end a radially 15 outwardly directed flange (42,43) for axial support and/or radial holding.
  7. 7. Hand-held machine tool according to one of Claims 4 to 6, characterized in that the holder (35) has two deep 20 drawn sleeves (38, 39) which are pushed axially into each other and their radially inwardly directed flanges (40,41) are axially spaced from each other, forming the annular flanks of the receptacle (36), in particular annular groove, on both sides.
  8. 8. Hand-held machine tool according to Claim 7, characterized in that the two sleeves (38,39) lie against each other by way of their radially outwardly directed flanges (42,43) and are axially supported on 30 the guide part (19) in the direction facing towards the tool holder (16) via a damping ring (34).
  9. 9. Hand-held machine tool according to Claim 7 or 8, characterized in that the two sleeves (38,39) are supported by way of their radially outwardly directed flanges (42,43) axially with respect to the tool 5 holder (16) in the direction facing away from the tool holder (16) by means of a ring (33), e.g. snap ring.
  10. 10. Hand-held machine tool according to any one of Claims 1 to 9, characterized in that the striking element 10 (18) has a circumferential sealing action together with the associated inner circumferential surface (22) of the guide part (19).
  11. 11. Hand-held machine tool according to any one of Claims 15 1 to 10, characterized in that the striking element (18) has a sealing ring (23), e.g. an O-ring, on its circumference.
  12. 12. Hand-held machine tool according to any one of Claims 20 1 to 11, characterized in that the inner circumferential surface (22) of the guide part (19) is designed as a sealing surface.
  13. 13. Hand-held machine tool according to any one of Claims 25 1 to 12, characterized in that the guide part (19) has at one end a radially inwardly directed annular edge (24) as an axial limit stop for the striking element (18) and is axially supported by the other end on a shoulder (31) in the direction facing towards the tool 30 holder (16).
    l
  14. 14. Hand-held machine tool according to any one of Claims 1 to 13, characterized in that the guide part (19) is accommodated and centred in a sleeve (30).
    5
  15. 15. Hand-held machine tool according to Claim 14, characterized in that the shoulder (31) and/or the sleeve (30) are in one piece with the tool holder (16). 10
  16. 16. Hand-held machine tool according to any one of Claims 7 to 9, characterized in that the shoulder (31) and the sleeve (30) are in one piece with each other.
  17. 17. A hand-held machine tool substantially as herein 15 described with reference to the accompanying drawings.
GB0326839A 2002-11-20 2003-11-18 Hand-held machine tool, in particular rotary or percussion hammer Active GB2395456B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE2002153972 DE10253972A1 (en) 2002-11-20 2002-11-20 Hand tool, in particular drilling or hammer

Publications (3)

Publication Number Publication Date
GB0326839D0 GB0326839D0 (en) 2003-12-24
GB2395456A true true GB2395456A (en) 2004-05-26
GB2395456B GB2395456B (en) 2005-07-20

Family

ID=29762170

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0326839A Active GB2395456B (en) 2002-11-20 2003-11-18 Hand-held machine tool, in particular rotary or percussion hammer

Country Status (3)

Country Link
CN (1) CN100341671C (en)
DE (1) DE10253972A1 (en)
GB (1) GB2395456B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2429425A (en) * 2005-08-04 2007-02-28 Bosch Gmbh Robert Hand tool machine with bearing bracket

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011075860A1 (en) * 2011-05-16 2012-11-22 Robert Bosch Gmbh Tool holder for machining tool e.g. drilling and/or chiseling tool, has front release actuation unit that limits range of motion of positive locking element via bearing unit along bearing axis movable with movement axis
DE102012212231A1 (en) * 2012-07-12 2014-01-16 Hilti Aktiengesellschaft Hand tool
CN106078622A (en) * 2016-08-17 2016-11-09 张家港市创基机械设备制造有限公司 Impact mechanism in electric impact drill

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2109739A (en) * 1981-11-13 1983-06-08 Black & Decker Inc A power tool having a plastics material housing
GB2136725A (en) * 1983-03-15 1984-09-26 Bosch Gmbh Robert Hammer, in particular drill hammer
US5373905A (en) * 1991-07-08 1994-12-20 Robert Bosch Gmbh Hammer drill

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2109739A (en) * 1981-11-13 1983-06-08 Black & Decker Inc A power tool having a plastics material housing
GB2136725A (en) * 1983-03-15 1984-09-26 Bosch Gmbh Robert Hammer, in particular drill hammer
US5373905A (en) * 1991-07-08 1994-12-20 Robert Bosch Gmbh Hammer drill

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2429425A (en) * 2005-08-04 2007-02-28 Bosch Gmbh Robert Hand tool machine with bearing bracket

Also Published As

Publication number Publication date Type
GB2395456B (en) 2005-07-20 grant
CN100341671C (en) 2007-10-10 grant
CN1502449A (en) 2004-06-09 application
GB0326839D0 (en) 2003-12-24 grant
DE10253972A1 (en) 2004-06-03 application

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