US20050180832A1 - Spindle with axially acting collet-opening device - Google Patents
Spindle with axially acting collet-opening device Download PDFInfo
- Publication number
- US20050180832A1 US20050180832A1 US10/480,050 US48005003A US2005180832A1 US 20050180832 A1 US20050180832 A1 US 20050180832A1 US 48005003 A US48005003 A US 48005003A US 2005180832 A1 US2005180832 A1 US 2005180832A1
- Authority
- US
- United States
- Prior art keywords
- spindle
- tool
- collet
- holding
- sleeve
- 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
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
- B23B31/02—Chucks
- B23B31/24—Chucks characterised by features relating primarily to remote control of the gripping means
- B23B31/26—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle
- B23B31/261—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle clamping the end of the toolholder shank
- B23B31/265—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle clamping the end of the toolholder shank by means of collets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2226/00—Materials of tools or workpieces not comprising a metal
- B23B2226/33—Elastomers, e.g. rubber
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2226/00—Materials of tools or workpieces not comprising a metal
- B23B2226/36—Epoxy
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2250/00—Compensating adverse effects during turning, boring or drilling
- B23B2250/12—Cooling and lubrication
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0011—Working of insulating substrates or insulating layers
- H05K3/0044—Mechanical working of the substrate, e.g. drilling or punching
- H05K3/0047—Drilling of holes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T408/00—Cutting by use of rotating axially moving tool
- Y10T408/94—Tool-support
- Y10T408/95—Tool-support with tool-retaining means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T409/00—Gear cutting, milling, or planing
- Y10T409/30—Milling
- Y10T409/309352—Cutter spindle or spindle support
- Y10T409/309408—Cutter spindle or spindle support with cutter holder
- Y10T409/309464—Cutter spindle or spindle support with cutter holder and draw bar
Definitions
- the present invention relates to machine tools that use spindles that rotate at high speeds, such as those of drilling assemblies for printed circuit boards.
- the invention relates to a spindle of the abovementioned type fitted with a tool-holding taper collet that can flex elastically to clamp the tool owing to the existence of a number of radial slits which give it the necessary elasticity.
- closure of the tool-holding collet is achieved by drawing it into a complementary tapering cavity, causing the various sectors of the end part of the clamp which are separated by the abovementioned radial slits to flex, squeezing and clamping the tool between themselves.
- the collet is inserted into the said complementary cavity by the reaction of precompressed elastic means interposed between the body of the tool-holding collet and the body of the spindle. If an axial force is then applied to the said collet, further compressing the abovementioned elastic means by a suitable amount, the contrary effect is obtained, that is the collet is opened allowing the tool to be extracted from it.
- the elastic means described above take the form of a series of Belleville washers arranged coaxially around the tool-holding collet, which are in contact with a special part of the collet, on which they exert a predetermined pressure due to the abovementioned precompression, keeping it closed during machining. If an axial force is applied to the tool-holding collet, via a rod passing through the interior of the spindle cavity containing the Belleville washers, the latter are further compressed to bring about this opening action of the collet.
- the inventor of the present innovation has devised a spindle of the type defined above, in which the said elastic means are not Belleville washers but instead a sleeve of elastic material (rubber or another elastomer) which also, under conditions of precompression, keeps the tool-holding collet in the closed position as described.
- This sleeve is fitted onto the free end of an extension of the said tool-holding collet, which ends near the corresponding end of the spindle, and can be reached without having to insert, as discussed, a long rod down into the body of the spindle.
- an epoxy resin bush which can be formed inside the spindle itself during the assembly operation and has a low coefficient of friction and permits movements in the axial direction of the tool-holding collet with virtually zero play.
- the subject of the present invention is therefore a spindle for machining at high rotational speeds as described in the appended claim 1 .
- FIG. 1 a longitudinal section, reduced in length, through a spindle of the type described above produced in accordance with the prior art
- FIG. 2 a longitudinal section, reduced in length, through a spindle of the same type as in FIG. 1 , but produced in accordance with the invention.
- a spindle 101 in accordance with the prior art consists of a body 101 s provided with a cavity 101 e in which a tool-holding collet 2 is inserted coaxially, with a drilling tool 3 inserted in turn into the latter.
- a flange 110 On the free end of the said tool-holding collet 2 is a flange 110 that is in contact with the series 15 of superposed Belleville washers arranged coaxially around the said tool-holding collet 2 .
- the Belleville washers are precompressed by a suitable amount when the spindle 101 and the tool-holding collet are assembled, so that their elastic reaction exerts a force F on the abovementioned flange 110 such as to push the tapered part of the tool-holding collet 2 into a cavity 4 of complementary shape formed in the body 101 s of the spindle. This causes it to contract elastically and clamps the tool 3 inside it. As already mentioned, this contraction is made possible by the existence of a number of radial slits (not shown in the drawings but obvious to those skilled in the art) formed in that part of the tool-holding collet which is intended to accommodate the shank of the tool.
- a force S is applied in the opposite direction to the said reaction force F of the series of Belleville washers 15 . This further compresses the washers and causes the collet 2 to move axially far enough to disengage its tapered part from the seat 4 , so that it opens due to the elastic return of the sectors of its part that contains the tool 3 shank, these sectors being separated from each other by the abovementioned radial slits.
- This force S is applied through a rod 13 aligned coaxially with the collet 2 , which is cyclically pressed against the aforesaid end part of the collet 2 to which the flange 110 is attached.
- FIG. 2 by contrast shows that a spindle 1 according to the invention likewise has a body 1 s provided with a coaxial cavity 1 e that contains the tool-holding collet 2 to which a tool 3 is fixed.
- the collet 2 is provided with an extension 8 , on the free end 8 m of which is fitted a flange 10 , the longitudinal section which is in the shape of an inverted U, with the two sides of the U pressing via their ends against the surface 7 s of a sleeve 6 of precompressed elastic material, for example rubber, which is housed coaxially between the inner wall of the said cavity 1 e of the body is of the spindle 1 and a shaped steel collar 7 applied coaxially to the outer surface of the said end 8 m of the extension 8 of the collet 2 .
- precompressed elastic material for example rubber
- this shaped collar is to prevent interference between the sleeve 6 , when it deforms radially, and the collet 2 , which could otherwise undesirably increase the force S necessary to move the collet 2 axially to open it.
- a bush 9 of epoxy resin with a low coefficient of friction which as mentioned earlier can be injected during the actual assembly stage, producing a fit with virtually zero play that permits relative movements between the collet 2 and the spindle 1 in precise alignment with their longitudinal axes, which coincide precisely with each other.
- the spindle 1 according to the invention achieves the desired object, making the cavity 1 e of the spindle 1 of a much smaller diameter compared with spindles of conventional type: a comparison of FIGS. 1 and 2 , which basically show the spindles at the same scale, will show that the outside diameter ⁇ 1 of the spindle 1 of the invention is about 25% less than the outside diameter ⁇ 101 of a spindle 101 of conventional type.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Gripping On Spindles (AREA)
- Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
- Earth Drilling (AREA)
Abstract
Description
- The present invention relates to machine tools that use spindles that rotate at high speeds, such as those of drilling assemblies for printed circuit boards.
- More particularly, the invention relates to a spindle of the abovementioned type fitted with a tool-holding taper collet that can flex elastically to clamp the tool owing to the existence of a number of radial slits which give it the necessary elasticity. In these spindles, as is known to those skilled in the art, closure of the tool-holding collet is achieved by drawing it into a complementary tapering cavity, causing the various sectors of the end part of the clamp which are separated by the abovementioned radial slits to flex, squeezing and clamping the tool between themselves.
- The collet is inserted into the said complementary cavity by the reaction of precompressed elastic means interposed between the body of the tool-holding collet and the body of the spindle. If an axial force is then applied to the said collet, further compressing the abovementioned elastic means by a suitable amount, the contrary effect is obtained, that is the collet is opened allowing the tool to be extracted from it.
- In the prior art, the elastic means described above take the form of a series of Belleville washers arranged coaxially around the tool-holding collet, which are in contact with a special part of the collet, on which they exert a predetermined pressure due to the abovementioned precompression, keeping it closed during machining. If an axial force is applied to the tool-holding collet, via a rod passing through the interior of the spindle cavity containing the Belleville washers, the latter are further compressed to bring about this opening action of the collet.
- However, the system described above has certain troublesome drawbacks: firstly, at the extremely high rotational speeds of the spindle that are currently achievable (over 100,000 rpm), the said Belleville washers are drawn round by the rotation, creating effects of unbalance which cause vibrations harmful to machining accuracy. Also, to accommodate Belleville washers with specifications suitable for the job, a large-diameter cavity must be formed in the spindle, which means that the spindle itself must have a large diameter and consequently a large mass.
- Moreover, with the system currently in use, it is necessary, as already discussed, to operate from the outside with a rod which must move cyclically into contact with the end of the tool-holding collet and exert upon it a force (of the order of some 2,000 N) which, over time, owing in part to the situation of point loading that occurs, can deform the tip and/or alignment of the rod, causing problems of accuracy and service life.
- In order to solve all the problems listed briefly above, the inventor of the present innovation has devised a spindle of the type defined above, in which the said elastic means are not Belleville washers but instead a sleeve of elastic material (rubber or another elastomer) which also, under conditions of precompression, keeps the tool-holding collet in the closed position as described. This sleeve is fitted onto the free end of an extension of the said tool-holding collet, which ends near the corresponding end of the spindle, and can be reached without having to insert, as discussed, a long rod down into the body of the spindle.
- In order for the radial expansion of the said sleeve not to create braking forces on the tool-holding collet, there is installed between the collet and the sleeve a shaped steel collar which, having a low coefficient of friction, does not significantly oppose the axial movement of the tool-holding collet.
- For similar reasons there is interposed, between the body of the spindle and the tool-holding collet, in that part of its extension which is not surrounded by the abovementioned sleeve, an epoxy resin bush, which can be formed inside the spindle itself during the assembly operation and has a low coefficient of friction and permits movements in the axial direction of the tool-holding collet with virtually zero play.
- The subject of the present invention is therefore a spindle for machining at high rotational speeds as described in the appended
claim 1. - A more detailed description will now be given of a preferred illustrative embodiment of a spindle according to the invention, selected from among the many that could be produced by a person skilled in the art in keeping with the teachings contained in the
abovementioned claim 1. - In the course of this description reference will also be made to the appended drawings, which show:
- in
FIG. 1 , a longitudinal section, reduced in length, through a spindle of the type described above produced in accordance with the prior art; - in
FIG. 2 , a longitudinal section, reduced in length, through a spindle of the same type as inFIG. 1 , but produced in accordance with the invention. - To begin with
FIG. 1 , this shows that aspindle 101 in accordance with the prior art consists of abody 101 s provided with acavity 101 e in which a tool-holding collet 2 is inserted coaxially, with adrilling tool 3 inserted in turn into the latter. - On the free end of the said tool-holding
collet 2 is aflange 110 that is in contact with theseries 15 of superposed Belleville washers arranged coaxially around the said tool-holdingcollet 2. The Belleville washers are precompressed by a suitable amount when thespindle 101 and the tool-holding collet are assembled, so that their elastic reaction exerts a force F on theabovementioned flange 110 such as to push the tapered part of the tool-holdingcollet 2 into acavity 4 of complementary shape formed in thebody 101 s of the spindle. This causes it to contract elastically and clamps thetool 3 inside it. As already mentioned, this contraction is made possible by the existence of a number of radial slits (not shown in the drawings but obvious to those skilled in the art) formed in that part of the tool-holding collet which is intended to accommodate the shank of the tool. - To open the tool-holding
collet 2, which will be abbreviated to “collet” below, a force S is applied in the opposite direction to the said reaction force F of the series of Bellevillewashers 15. This further compresses the washers and causes thecollet 2 to move axially far enough to disengage its tapered part from theseat 4, so that it opens due to the elastic return of the sectors of its part that contains thetool 3 shank, these sectors being separated from each other by the abovementioned radial slits. - This force S is applied through a
rod 13 aligned coaxially with thecollet 2, which is cyclically pressed against the aforesaid end part of thecollet 2 to which theflange 110 is attached. -
FIG. 2 by contrast shows that aspindle 1 according to the invention likewise has abody 1 s provided with acoaxial cavity 1 e that contains the tool-holdingcollet 2 to which atool 3 is fixed. In this case thecollet 2 is provided with anextension 8, on thefree end 8 m of which is fitted aflange 10, the longitudinal section which is in the shape of an inverted U, with the two sides of the U pressing via their ends against thesurface 7 s of asleeve 6 of precompressed elastic material, for example rubber, which is housed coaxially between the inner wall of the saidcavity 1 e of the body is of thespindle 1 and ashaped steel collar 7 applied coaxially to the outer surface of the saidend 8 m of theextension 8 of thecollet 2. As already stated, the function of this shaped collar is to prevent interference between thesleeve 6, when it deforms radially, and thecollet 2, which could otherwise undesirably increase the force S necessary to move thecollet 2 axially to open it. - The operations of closing and opening the
collet 2 are similar to those already described with reference to the case discussed earlier: the elastic reaction F of theprecompressed sleeve 6 on the said inverted-U flange 10 of thecollet 2 holds the latter in the closed, tool-clamping position, and to open thecollet 2, the said force S is applied to theend 8 m of itsextension 8, further compressing theelastic sleeve 6 and moving the saidcollet 2 axially the necessary distance. To facilitate the axial movement of the collet the inventor has interposed, between the part 8 n of the saidextension 8 of thecollet 2 which is not surrounded by the saidelastic sleeve 6 and the body Is of thespindle 1, abush 9 of epoxy resin with a low coefficient of friction, which as mentioned earlier can be injected during the actual assembly stage, producing a fit with virtually zero play that permits relative movements between thecollet 2 and thespindle 1 in precise alignment with their longitudinal axes, which coincide precisely with each other. - As already noted, owing to the characteristics of the component parts of the
spindle 1 of the invention, and in particular those of theelastic sleeve 6, thespindle 1 according to the invention achieves the desired object, making thecavity 1 e of thespindle 1 of a much smaller diameter compared with spindles of conventional type: a comparison ofFIGS. 1 and 2 , which basically show the spindles at the same scale, will show that the outside diameter Ø1 of thespindle 1 of the invention is about 25% less than the outside diameter Ø101 of aspindle 101 of conventional type. - Though this is well known to those skilled in the art, it is relevant to add a final detail on how both spindles 1 and 101 described above work: when the said force S is being applied to the
collet 2 to open it by moving it axially relative to the body of the spindle, the body is prevented from moving by supporting it against afixed contact surface 5.
Claims (4)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH3172002 | 2002-02-22 | ||
CH0317/02 | 2002-02-22 | ||
PCT/IB2003/000365 WO2003070424A1 (en) | 2002-02-22 | 2003-02-04 | Spindle with axially acting collet-opening device |
Publications (2)
Publication Number | Publication Date |
---|---|
US6929437B1 US6929437B1 (en) | 2005-08-16 |
US20050180832A1 true US20050180832A1 (en) | 2005-08-18 |
Family
ID=27740057
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/480,050 Expired - Fee Related US6929437B1 (en) | 2002-02-22 | 2003-02-04 | Spindle with axially acting collet-opening device |
Country Status (6)
Country | Link |
---|---|
US (1) | US6929437B1 (en) |
EP (1) | EP1476274B1 (en) |
AT (1) | ATE297287T1 (en) |
AU (1) | AU2003246853A1 (en) |
DE (1) | DE60300819T2 (en) |
WO (1) | WO2003070424A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI661885B (en) * | 2018-10-19 | 2019-06-11 | 鼎朋企業股份有限公司 | Chuck with detachable components |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB0311852D0 (en) * | 2003-05-22 | 2003-06-25 | Westwind Air Bearings Ltd | Rotary tool holder assemblies |
DE102014117571B3 (en) * | 2014-12-01 | 2016-02-18 | Ott-Jakob Spanntechnik Gmbh | jig |
CN111113113A (en) * | 2020-02-18 | 2020-05-08 | 东莞市百方建航机械配件有限公司 | Eight-claw clamp mechanism for inner support or outer clamp of numerical control lathe |
CN114269067B (en) * | 2021-11-25 | 2024-02-20 | 成都金大立科技有限公司 | Conveying switching device for PCB processing |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4605349A (en) * | 1985-01-07 | 1986-08-12 | Cincinnati Milacron Inc. | Spring centering device for tool spindles |
US4790700A (en) * | 1984-07-30 | 1988-12-13 | Schwartzman Everett H | Integral spring flexure for use with high speed rotating shafts |
US4986704A (en) * | 1987-11-24 | 1991-01-22 | Okuma Mahinery Works Ltd. | Tool mounting apparatus |
US6287059B1 (en) * | 1997-04-03 | 2001-09-11 | Sodick Co., Ltd. | Machine tool clamping device |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3824581A1 (en) * | 1988-07-19 | 1990-01-25 | Ott Gmbh A | Clamping device on a machine-tool spindle |
-
2003
- 2003-02-04 AT AT03742623T patent/ATE297287T1/en not_active IP Right Cessation
- 2003-02-04 US US10/480,050 patent/US6929437B1/en not_active Expired - Fee Related
- 2003-02-04 DE DE60300819T patent/DE60300819T2/en not_active Expired - Fee Related
- 2003-02-04 WO PCT/IB2003/000365 patent/WO2003070424A1/en not_active Application Discontinuation
- 2003-02-04 EP EP03742623A patent/EP1476274B1/en not_active Expired - Lifetime
- 2003-02-04 AU AU2003246853A patent/AU2003246853A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4790700A (en) * | 1984-07-30 | 1988-12-13 | Schwartzman Everett H | Integral spring flexure for use with high speed rotating shafts |
US4605349A (en) * | 1985-01-07 | 1986-08-12 | Cincinnati Milacron Inc. | Spring centering device for tool spindles |
US4986704A (en) * | 1987-11-24 | 1991-01-22 | Okuma Mahinery Works Ltd. | Tool mounting apparatus |
US6287059B1 (en) * | 1997-04-03 | 2001-09-11 | Sodick Co., Ltd. | Machine tool clamping device |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI661885B (en) * | 2018-10-19 | 2019-06-11 | 鼎朋企業股份有限公司 | Chuck with detachable components |
Also Published As
Publication number | Publication date |
---|---|
ATE297287T1 (en) | 2005-06-15 |
EP1476274B1 (en) | 2005-06-08 |
AU2003246853A1 (en) | 2003-09-09 |
EP1476274A1 (en) | 2004-11-17 |
DE60300819D1 (en) | 2005-07-14 |
DE60300819T2 (en) | 2005-11-10 |
US6929437B1 (en) | 2005-08-16 |
WO2003070424A1 (en) | 2003-08-28 |
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Owner name: BALLADO INVESTMENTS, INC., PANAMA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AMMANN, BEAT;REEL/FRAME:015253/0312 Effective date: 20031129 |
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