GB2063141A - A hand machine tool provided with an air-spring percussion mechanism - Google Patents
A hand machine tool provided with an air-spring percussion mechanism Download PDFInfo
- Publication number
- GB2063141A GB2063141A GB8035391A GB8035391A GB2063141A GB 2063141 A GB2063141 A GB 2063141A GB 8035391 A GB8035391 A GB 8035391A GB 8035391 A GB8035391 A GB 8035391A GB 2063141 A GB2063141 A GB 2063141A
- Authority
- GB
- United Kingdom
- Prior art keywords
- machine tool
- hand machine
- piston
- tool according
- plastics material
- 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
Links
- 238000009527 percussion Methods 0.000 title claims abstract description 5
- 239000000463 material Substances 0.000 claims abstract description 20
- 239000004033 plastic Substances 0.000 claims abstract description 19
- 229920003023 plastic Polymers 0.000 claims abstract description 19
- 239000003365 glass fiber Substances 0.000 claims abstract description 12
- 239000004952 Polyamide Substances 0.000 claims abstract 3
- 229920002647 polyamide Polymers 0.000 claims abstract 3
- 241001125879 Gobio Species 0.000 claims description 9
- 238000007789 sealing Methods 0.000 claims description 4
- 239000013013 elastic material Substances 0.000 claims 1
- 239000007769 metal material Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 241001125877 Gobio gobio Species 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D17/00—Details of, or accessories for, portable power-driven percussive tools
- B25D17/11—Arrangements of noise-damping means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D11/00—Portable percussive tools with electromotor or other motor drive
- B25D11/06—Means for driving the impulse member
- B25D11/12—Means for driving the impulse member comprising a crank mechanism
- B25D11/125—Means for driving the impulse member comprising a crank mechanism with a fluid cushion between the crank drive and the striking body
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D17/00—Details of, or accessories for, portable power-driven percussive tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D17/00—Details of, or accessories for, portable power-driven percussive tools
- B25D17/06—Hammer pistons; Anvils ; Guide-sleeves for pistons
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
- B25D2217/0011—Details of anvils, guide-sleeves or pistons
- B25D2217/0015—Anvils
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
- B25D2217/0011—Details of anvils, guide-sleeves or pistons
- B25D2217/0019—Guide-sleeves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D2217/00—Details of, or accessories for, portable power-driven percussive tools
- B25D2217/0011—Details of anvils, guide-sleeves or pistons
- B25D2217/0023—Pistons
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D2222/00—Materials of the tool or the workpiece
- B25D2222/06—Composite materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D2222/00—Materials of the tool or the workpiece
- B25D2222/54—Plastics
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Percussive Tools And Related Accessories (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
Abstract
A hand machine tool provided with an air-spring percussion mechanism is proposed in which the guide cylinder (2), the piston (23) and the gudgeon pin (26) are made of elastic plastics material similar in kind at least as regards their heat expansion, especially a polyamide. Due to the use of the said material, which is preferably reinforced with glass fibres, and due to the particular formation of the components referred to matching the properties of the material, a better efficiency, a quieter vibration free running and a more comfortable handling is achieved due to lower heating of the external housing portions and a better protection for the components of the hand machine tool is also achieved. <IMAGE>
Description
SPECIFICATION
A hand machine tool provided with an air-spring percussion mechanism
The invention originates from a hand machine tool according to the preamble to the main claim. Such a
hand machine tool is already known from German
OS 22 60 365. With hand machine tools of this kind, the pistons are made of steel or like metal, the guide tube is made of steel and the gudgeon pins are also
made of steel. During operation, they vibrate very strongly and are very loud. The heat developed by the compression causes a considerable heating of the metal parts and of the hand machine tool including its housing. That is extremely uncomfortable for the operator especially during a long operation. The heat losses occurring reduce the efficiency of the hand machine tool considerably.
Also the working life of the driving motor for the hand machine tool and its other machine parts are shortened by the severe heating.
Advantages of the invention
As opposed to this, the hand machine tool in accordance with the invention comprising the characterising features of the main claim has the advantage of quiet running which is produced by the fit of the piston in the guide cylinder as relatively tightly as possible which in its turn is facilitated by the uniform heat expansion of the said parts. Furthermore, the vibrations of the hand machine tool housing are greatly reduced by the reduced masses of the piston and of the gudgeon pin. The shocks occurring due to the impact of the striker are damped by the guide cylinder in accordance with the invention. Thus, the hand machine tool is generally quieter. Finally, the thermal efficiency of the airspring percussion mechanism is also improved as a result of the low heat conductivity of the guide cylinder, of the piston and of the gudgeon pin.The substantially adiabatic change of state arises from the previous polytropic change of state during the compression and subsequent expansion of the airspring. The housing of the hand machine tool becomes less hot which is advantageous for the operator and the working life of the hand machine tool is increased due to the lower heating of its machine parts.
Advantageous further developments and improvements of the hand machine tools set forth in the main claim are made possible by the measures set forth in the sub-ciaims. The filling of the plastics material of the said constructional parts with glass fibre rovings orientated according to claims 9 and 10, is especially advantageous.
Drawing
An embodiment of the subject matter of the invention is illustrated in the drawing and is described ip detail in the following specification. The figure shows a longitudinal section through a portion of a hand machine tool produced in accordance with the invention.
Description ofthe embodiment
A guide cylinder 2 made of plastics material is fixed in a housing 1. At its front end, the housing 1
receives a tool holder 3. The latter is bolted by its end onto the housing 1 by means of bolts 4. The tool holder 3 has a cylindrical bore 5 and a shaped guide 6 for the shank of a tool (not shown). The cylindrical bore 5 accommodates the piston head of a dolly 7 provided with sealing rings 8. A cylindrical extension 9 on the tool holder 3 engages in a corresponding cylindrical bore 10 in the housing 1. The cylindrical bore 10 is stepped and changes into a bore 11 by which the reduced neck 12 of the dolly 7 engages in the interior of the guide cylinder 2. A washer 15 and an elastic ring 16 are inserted in the housing 1 between the bores 10 and 11 and between a rear end surface 13 of the cylindrical extension 9 and the end surface 14 of the shoulder.Moreover, the washer 15 is arranged to rest against the step between the neck 12 and the piston portion of the dolly 7 wherein the neck 12 passes through the bores in the washer 15 and in the elastic ring 16. The interior of the guide cylinder 2 is in communication with the atmosphere through the air inlets 17 to 20. A striker 21 is arranged in the guide cylinder 2 and is guided in the cylinder bore by elastic guide rings 22. A gap of about 1 mm is provided between the periphery of the striker 21 and the inner wall of the guide cylinder 2. A piston 23 is also fitted in the bore of the guide cylinder 2. This piston 23 is likewise made of plastics material which has the same coefficient of expansion as the plastics material from which the guide cylinder 2 is made. In these circumstances, the fitting between the guide cylinder 2 and the piston 23 can be made comparatively tight.This produces a good guiding. A sealing ring 24 for the piston 23 closes the inner space of the guide cylinder 2 at the piston end in an airtight manner. The same air-tight ciosure is achieved on the side of the striker 21 at least by the guide ring 22 nearer to the piston 23. The connection between the piston 23 and a connecting rod 25, likewise preferably made of plastics material, is provided by a gudgeon pin 26 which is also made of plastics material. A longitudinal bore 27 makes the gudgeon pin 26 lighter and more resilient. A housing cover 28 likewise made of plastics material in known manner covers and protects the housing 1. The remaining parts, not shown, together with those which are shown, form a hand machine tool comprising a motor, a gearbox, switches, connections and at least one handle. The plastics material used for the guide cylinder 2 and the piston 23 is reinforced by a glass fibre filling which consists at least partially of annular glass fibre rovings orientated about the longitudinal axis of the guide cylinder 2. The plastics material of the gudgeon pin 26 is reinforced by glass fibres which are orientated at least substantially in its longitudinal direction. It has proved to be especially advantageous when the portion of the glass fibre rovings orientated in the stated manner amounts to more than 60% of the glass fibre filling of the plastics material.
Claims (13)
1. A hand machine tool provided with an airspring percussion mechanism, in which a piston and a striker are both axially guided for movement in a guide cylinder, characterised in that, the piston and its guide cylinder consist of a heat resistant elastic plastics material.
2. A hand machine tool according to claim 1 characterised in that the piston and its guide cylinder consist of a plastics material, especially a polyamide, of a similar kind in respect of its heat expansion.
3. A hand machine tool according to one of claims 1 and 2 characterised in that the striker made of metallic material, is fitted in the bore in the guide cylinder with a large clearance amounting to approximately 1 mm and is guided in the said bore by
O-rings of elastic material inserted in annular grooves in the said striker.
4. A hand machine tool according to one of claims 1 to 3 characterised in that the gudgeon pin connecting the piston to its piston rod (connecting
rod) likewise consists of an elastic plastics material, especially a polyamide.
5. A hand machine tool according to claim 4 characterised in that the gudgeon pin is formed by a
plastics tube.
6. A hand machine tool according to one of claims 1 to 5 characterised in that the piston is
provided with a sealing ring and the nearer to the
piston of the two guide rings on the striker is likewise formed as a sealing ring.
7. A hand machine tool according to one of claims 1 to 6 characterised in that the piston and the
guide cylinder are fitted in one another with a close tolerance.
8. A hand machine tool according to one of
claims 1 to 7 characterised in that a plastics material with a bad heat conductivity is used.
9. A hand machine tool according to one of
claims 1 to 8 characterised in that the plastics
material is filled with cut lengths of glass fibre.
10. A hand machine tool according to one of
claims 1 to 9 characterised in that the plastics
material of the piston and of the guide cylinder is
reinforced by annular glass fibre rovings orientated
about their longitudinal axes.
11. A hand machine tool according to one of
claims 1 to 8 characterised in that the plastics
material of the gudgeon pin is reinforced by glass fibre rovings orientated in its longitudinal direction.
12. A hand machine tool according to one of
claims 10 and 11 characterised in that the portion of
the glass fibre rovings orientated in the stated
manner amounts to more than 60% of the glass fibre
filling.
13. A hand machine tool substantially as herein
described with reference to the accompanying
drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792945935 DE2945935A1 (en) | 1979-11-14 | 1979-11-14 | HAND MACHINE TOOL WITH AN AIR SPRING PERFORMANCE |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2063141A true GB2063141A (en) | 1981-06-03 |
| GB2063141B GB2063141B (en) | 1984-01-11 |
Family
ID=6085951
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8035391A Expired GB2063141B (en) | 1979-11-14 | 1980-11-04 | Hand machine tool provided with an airspring percussion mechanism |
Country Status (3)
| Country | Link |
|---|---|
| CH (1) | CH647188A5 (en) |
| DE (1) | DE2945935A1 (en) |
| GB (1) | GB2063141B (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1027963A3 (en) * | 1999-02-09 | 2003-03-26 | Black & Decker Inc. | Rotary hammer |
| EP1027964A3 (en) * | 1999-02-09 | 2003-04-09 | Black & Decker Inc. | Rotary hammer |
| EP2163355A1 (en) * | 2008-09-12 | 2010-03-17 | AEG Electric Tools GmbH | Electric tool comprising an oscillating drive or crank drive with reduced mass |
| EP2243580A3 (en) * | 2009-04-20 | 2011-05-25 | HILTI Aktiengesellschaft | Pneumatic striking mechanism and handheld machine tool with such a mechanism |
| DE102012211941A1 (en) | 2012-07-09 | 2014-01-09 | Hilti Aktiengesellschaft | Hand machine tool e.g. drilling hammer, has guide tube whose inner surface is formed with layer containing amorphous or fine-grained metallic matrix, and pressure chamber which is provided for accelerating percussion piston |
| EP2910336A1 (en) | 2014-02-21 | 2015-08-26 | HILTI Aktiengesellschaft | Power tool |
| EP2275232B1 (en) | 2009-07-15 | 2015-09-09 | Black & Decker Inc. | Motor driven hammer having means for controlling the power of impact |
| EP2448721A4 (en) * | 2009-07-01 | 2016-05-11 | Atlas Copco Rock Drills Ab | DEVICE AND METHOD FOR PROTECTING CORROSION ROCK DRILLING MACHINE |
| US10344861B2 (en) | 2015-04-24 | 2019-07-09 | Caterpillar Inc. | Hammer having composite piston sleeve |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4179159B2 (en) * | 2003-12-18 | 2008-11-12 | 日立工機株式会社 | Impact tool |
| EP1872913B1 (en) | 2006-07-01 | 2015-08-19 | Black & Decker, Inc. | A tool holder for a hammer apparatus |
| AU2007202971A1 (en) | 2006-07-01 | 2008-01-17 | Black & Decker, Inc. | A lubricant pump for a hammer drill |
| US7413026B2 (en) | 2006-07-01 | 2008-08-19 | Black & Decker Inc. | Lubricant system for powered hammer |
| EP1872914B1 (en) | 2006-07-01 | 2010-09-22 | Black & Decker, Inc. | A Pavement Breaker |
| EP1872910B1 (en) | 2006-07-01 | 2012-11-21 | Black & Decker, Inc. | Method for mesuring the amount of wear of a nose of beat piece in a hammer drill |
| DE102015220256A1 (en) * | 2015-10-19 | 2017-04-20 | Mahle International Gmbh | Method for producing a piston |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3040712A (en) * | 1959-04-17 | 1962-06-26 | Firco Inc | Cylinder, piston and rod assembly |
| US3239589A (en) * | 1961-10-18 | 1966-03-08 | Charles S White | Method of forming a low friction piston in a cylinder |
| FR1375013A (en) * | 1963-04-18 | 1964-10-16 | Process for using plastic matrix by coating pistons and cylinders as well as for the production of segments | |
| NL135632C (en) * | 1965-10-20 | |||
| DE2260365A1 (en) * | 1972-12-09 | 1974-06-12 | Bosch Gmbh Robert | AIR CUSHION STRIKING |
-
1979
- 1979-11-14 DE DE19792945935 patent/DE2945935A1/en not_active Ceased
-
1980
- 1980-10-23 CH CH790680A patent/CH647188A5/en not_active IP Right Cessation
- 1980-11-04 GB GB8035391A patent/GB2063141B/en not_active Expired
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1027964A3 (en) * | 1999-02-09 | 2003-04-09 | Black & Decker Inc. | Rotary hammer |
| EP1027963A3 (en) * | 1999-02-09 | 2003-03-26 | Black & Decker Inc. | Rotary hammer |
| EP2163355A1 (en) * | 2008-09-12 | 2010-03-17 | AEG Electric Tools GmbH | Electric tool comprising an oscillating drive or crank drive with reduced mass |
| US9199369B2 (en) | 2009-04-20 | 2015-12-01 | Hilti Aktiengesellschaft | Pneumatic striking mechanism and hand-held power tool |
| EP2243580A3 (en) * | 2009-04-20 | 2011-05-25 | HILTI Aktiengesellschaft | Pneumatic striking mechanism and handheld machine tool with such a mechanism |
| EP2448721A4 (en) * | 2009-07-01 | 2016-05-11 | Atlas Copco Rock Drills Ab | DEVICE AND METHOD FOR PROTECTING CORROSION ROCK DRILLING MACHINE |
| EP2275232B1 (en) | 2009-07-15 | 2015-09-09 | Black & Decker Inc. | Motor driven hammer having means for controlling the power of impact |
| EP2275232B2 (en) † | 2009-07-15 | 2018-07-25 | Black & Decker Inc. | Motor driven hammer having means for controlling the power of impact |
| DE102012211941A1 (en) | 2012-07-09 | 2014-01-09 | Hilti Aktiengesellschaft | Hand machine tool e.g. drilling hammer, has guide tube whose inner surface is formed with layer containing amorphous or fine-grained metallic matrix, and pressure chamber which is provided for accelerating percussion piston |
| DE102012211941B4 (en) * | 2012-07-09 | 2021-04-22 | Hilti Aktiengesellschaft | Machine tool and manufacturing process |
| WO2015124470A1 (en) * | 2014-02-21 | 2015-08-27 | Hilti Aktiengesellschaft | Hand-held power tool |
| EP2910336A1 (en) | 2014-02-21 | 2015-08-26 | HILTI Aktiengesellschaft | Power tool |
| US10344861B2 (en) | 2015-04-24 | 2019-07-09 | Caterpillar Inc. | Hammer having composite piston sleeve |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2945935A1 (en) | 1981-05-27 |
| GB2063141B (en) | 1984-01-11 |
| CH647188A5 (en) | 1985-01-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |