CA1073651A - Draw-in-collet chuck - Google Patents
Draw-in-collet chuckInfo
- Publication number
- CA1073651A CA1073651A CA285,382A CA285382A CA1073651A CA 1073651 A CA1073651 A CA 1073651A CA 285382 A CA285382 A CA 285382A CA 1073651 A CA1073651 A CA 1073651A
- Authority
- CA
- Canada
- Prior art keywords
- collet
- work
- chuck
- stationary rod
- draw
- 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.)
- Expired
Links
Landscapes
- Gripping On Spindles (AREA)
Abstract
Abstract of the Disclosure:
A draw-in-collet chuck which comprises a flange body adapted to be mounted on a lathe and having a hub extending from the flange body, a stationary rod fixedlly supported by the flange body and having a tapered nose, and a collet axially movable in concentric relation with the stationary rod. The collet has a taper-hole with which the tapered nose of the stationary rod engages when the collet is moved toward the stationary rod, and a chuck portion of the collet spreads outward, firmly holding a work.
A draw-in-collet chuck which comprises a flange body adapted to be mounted on a lathe and having a hub extending from the flange body, a stationary rod fixedlly supported by the flange body and having a tapered nose, and a collet axially movable in concentric relation with the stationary rod. The collet has a taper-hole with which the tapered nose of the stationary rod engages when the collet is moved toward the stationary rod, and a chuck portion of the collet spreads outward, firmly holding a work.
Description
1C1736S~
. . , This invention relates ~o collet chucks for lathes and, more particularly, to a draw-in-co,llet chuck adapted to oe used for high precision work in the lathe.
In prior art, it has been a common practice to use a ~
collet chuck to hold a ring-shaped work for machining. This type of chuck is usually composed of a collet screwed into a flange secured to a lathe, and an axially movable spindl~ wibh its ena formed with a tapered nose adapted bo be brought into engagement with a conical wall of the colleb whereby a holding portion of the collet is diametrically spread out, thareby firmly holding work. With this expedient, since the holding portion of the collet is frequently spread out by the action of the axially movable spindle and subjected to alternating load during machining operation, the colleb is caused to deflect so that the workpiece is held in an oI'f-centered posi-tion. In this case, it is difficult to perform high precision work. In the collet chuck of the type noted above, further, since the workpiece is caused to abut against the stop or annular shoulder . .
of the collet by the worker;~s hand and, under this condition, the collet .
is spread out, the worker bends to release his hand-away ~om the workpiece ~ before it is completely chucked by the collet with a resultant inaccurate ; 20 holding o~ the workpiece.
It is, therefore, an object of the present in~en-tion to provide a new and use~ul collet chuck which can overcomes the shortcomings encountered in the prior art.
It i9 another object of the present invention to provide a draw-in-collet chuck adapted to hold a workpiece in a highly reliable ,. . .
. ~.
,.
.
107365~
manner.
It is another o~ject of the present invention to provide a draw-in-collet chuck adapted to hold a workpiece in an on-center position during machining operation for thereby allowing high precision work.
i~ It is still another oBject of ~he present invention to prov~de a draw-in-collet chuck which is rigid in construction, easy to manipulate, and ready to be installed in anylkind of existing lathes.
It is a further object of the present invention to proYide a draw-in-collet chuck which is simple in construction and low in manufacturing cost.
In accordance with one broad aspect, the invention relates to a draw-in-collet chuck comprising: a flange body adapted to be mounted on a machine and including a hub extending axially from the flange body; a stationary rod fixedly supported by said flange body in concentric relation therewith, said stationary rod including a taperad nose provided at one end of the rod; a collet axially movable in concentric relation with said stationary rod and including a chuck portion circumferentially divided into several pieces to allow an outer diameter of the chuck portion to vary, and a taper hole formed inside of said collet at a position opposite to said tapered nose; and a s~opper mounted on said hub of said flange body to limit an axial movement of a work held by said chuck portion; said taper hole being engageable with said tapered nose of said stationary rod when said collet is moved toward said stationary rod, whereby the outer diameter of the chuck portion is increased so that the chuck portion of the collet is brought into pressured contact with an inner periphery of the work and the face of the work is pressured contact with said stopper; and wherein said stopper is mounted ,~, 1;
~ 3 _ )736Sl on said hub ~y means of an axially movable adjustment guide whereby the position of the stopper can be adjusted.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a partially cut-away view of a draw-in-collet chuck according to the present invention ~ ig. 2 is a cross-sectional view taken on line II~
; 10 of Fig. l;
Fig. 3 is an exploded view of the collet chuck shown in F~g. l;
Fig. 4 is a cross-sectional view showing a modified form of the collet chuck shown in Fig. 1;
Fig. S is a cross-sectional view showing another modifica~ion of the collet chuck shown in Fig. l; and Fig. 6 ~s a view illustrating the size of each paxt of a work.
Referring now to Figs. 1 to 3 of the drawings, there is , 2Q shown a preferred embodiment of a draw-in-collet chuck embodying the present invention. The collet chuck, generally designated as 10, comprises a flange 1 - 3a -, .. . .
~07365~
, body 12 adapted to be mounted on a lathe 14, a draw-in member 16, a s-tationary rod or sha~t 18 ~ixedly supported by the flange body 12 wi~h the end being formed with a tapered nose 18a, an axially movable collet - 20 adapted to hold a work A, and a stopper 22 serving as a means for engaging with and limiting the face of the work A.
The flange body 12 has a hub 12a axially extending ~rom -the flange bodyO The hub 12a is formed at its inner p0riphery with a threaded portion 24 and a tapered bore 26, -to which tapèred portions 18b radially extending ~rom the stationary rod 18 are ~itted. Threaded portions 18c o~
the stationary rod 18 screws into the -threaded portion 24 o~ the hub 12a and, thus, the stationary rod 18 is held stationary by the hub 12a. As best shown in Figs. 2 and 3, the circum~erentially divided tapered portions 18b of the stationary rod 18 de~ine sector spaces 18d, through which a circumferentially divided sleeve portion 16a o~ the draw-in member 16 extends toward the collet 20. The le~tward end of the draw-in ; member 16 is threaded as at 16c, to threadably accommodate therein a connecting rod (not shown) which i~terconnects the draw-in member 16 .
to a piston rod (not shown) o~ a hydraulic cylinder. Thus, the draw-in member 16 is movable in an axial direction togebher with the piston rod o~ the hydraulic cylinder. The sleeve portion 16a o~ the Araw-in member 16 is threaded at its end, which screws into one end of the collet 20.
In this manner, the draw-in member 16 is interconnected with the collet 20 and axially movable therewith,relative to the stationary rod 18. The collet 20 has a cylindrical section 20a slidably received in an inner bore 27 o~
the hub 12a. As shown in Pig. 3, the cylindrical section 20a has on its .
.... . .. . . .. . .. . . . . . .. . ... . ..
~a~736S~L
outer periphery an axially extending slot 28, with which an end of guide screws 30 screwed into the hu~ 12a engages to prevent rotation of the collet 20 relative to the hub 12a.
As shown in Fig. 3, the collet 20 also has a tapered section 20b and a chuck portion 20c which is circumferentially d~vided by slits 29 to provide three sectors adapted to engage with an inner wall of the work A as shown in Fig. 1. The chuck portion 20c has a taper hole 32 with which the tapered nose 18a o the stationary rod 18 engages, spreading the chuck portion 20c outward when the collet 20 is moved leftward as viewed in Fig. 1 by the action of the draw-in ~em~er 16. Indicated as 34 is an axial projection which is provided for machining the outer periphery of the chuck portion 20c in conormity with the inner periphery of the work A. To this end, a ring tnot shown) i~ placed onto the axial projection 34 to prevent the chuck portion 20c from being spread outward and, thereafter, the chuck portion 20c is applied with spreading force by the action of the draw-in member 16. Under this condition, the outer periphery of the chuck portion or section 20c is machined. During this machining, since the stationary rod 18 is held stationary by the flange body 12 and the taper hole 32 of the chuck section 20c is caused to engage with the tapered nose 18a of the rod 18 by the action of the draw-in member 16, the outer periphery of the chuck section 20c is accurately centered after it has been worked. It should be noted that while the tapered nose 18a has been shown and described with reference to an example in which it engages with the taper hole 32 the taper hole 34 may be replaced with a straight hole with which the nose 18a may engage.
The collet chuck constructed as mentioned above will operate in _ 5 _ 1~7365~ .
: .
the following manner:
The work A with its inner diameter machined in a given size is placed over the chuck portion 20a of the collet 20 as shown in Fig. 1.
Next, the hydraulic cylinder is actuated to cause the piston rod to draw the draw-in member 16 leftward as viewed in Fig. 1, moving the collet 20 in the same direction. In this instance, the nose 18a of the stationary rod 18 engages with the taper hole 32 o~ the chuck portion 20c, which is consequently spread outward with the increase ln its outer diameter.
Therefore, tha outer periphery of -the chuck portion 20c engages with the inner periphery o~ the work A. During le~tward movement o~ the colle-k 20, the work A is pulled in the same direction as the collet 20 a~ter it has engaged with the work A, 90 the work 1 is moved leftward and abuts against the s-topper 22 by which the work A is axially positioned. The work is held or maintained in a fixed position under the above-noted condition and, hence, , 15, axial movement of the work is prevented in a reliable manner during machining opratio~. Thus, the outer perlphery and face of the work A can - be easily machined in a high precision. After machining operation has ceased, the work A is removed from the chuck 10 by moving the dra~-in member 16 and ~ .
accordingly the collet 20 rightward in ~ig. 1. It will be seen in Fig. 1 that tho stopper 22 is conneoted to an adjustment guide 36 which is threaded over the hub 12 and axially movable to effect positioning o~ the stopper with respect to the work A. Indicated at 38 is a lock nut which, when the adjustment guide 36 is positioned bo a given location, is turned to lock the adjustment guide 36.
It will now be appreciated from tha foregoing description that ' ~G~7365~ `
in accordance with the present invention since the work A is supported by both o~ the stationary rod 18 and the collet 20 coi~cting with each other, the work A is satis~actorily preventea ~rom being o~ centered during heavy work or load. This is ensured by the hub 12a ~f the flange body 12 which is highly ~igid in constructio?n. Since~ further~ the work A is positioned by moving the collet 20 rela-tive to the stationi~ry rod 18 ~ixedly suppo~ted by the hub 12a in coaxial relationship with one another, the work A iisi highl~ reliably fix~??d in ~n-center position. Since the prior art collet chuck has a collet i~e`d to a flange body and adapted to spread by the action of a movable spindle whereby the work is supported, the collet i5 caused to deflect from its center line duriug machining operation of a lathe. During mounting of the work onto the collet, the movable spindle fits the collet to spread the same under a condition in which the collet is off-centered. It is thus difficult to adjust the collet to an on-center position and high precision work can not be obtained in a reliable manner. In the present invention, on the contrary, since the collet is brought to an on-center position by the tapered nose o the .
stationary rod and the work i9 adapted to be supported by both of the collet and the stationary support during machining operation, no o~f-centering of the collet is caused and high precision work can be attained for a long period of time.~
Fig. 4 shows a modified form of the collet chuck shown in Figs.
1 to 3, with like parts bearing the same reference numerals as those used in ~i~ .
Figs. 1 to 3 except that a single prime ~') has been added to~the~numeral indi~ative of a modified element. In Fig. 4, the stopper 22' is directly ., , . .
screwed into the hub 12a o~ the flange body (no$ sh~wn) and the collet 20' is held by a holder (not shown) at a position in front of the flange body.
The collet 20' has a plurali~y of slits 29' to permit radial deflec~ion of the chuck portion 20'c. The holder is arranged to be movable along a S path ~para~lel~ to:l~ the axls of the stationary rod 18 fixedly supportedby the flange body so that the collet 20' is movable in concentric with the stationary rod 18.
With~the above arrangement, the work A is placed in front of the stopper 22' and, subsequently, the collet 20' is moved leftward as ~iewed in Fig. 4 so that the collet portion 20'c goes through the work A.
/further When the collet 20' is moved leftward, ~he taper hole 32' engages with the tapered nose 18a of the stationary rod 18 by which the chuck portion 20'C 18 spread outward and the outer periphery;of~the;chuck portion 20'c is brought into pressured contact with the inner periphery of the work A.
In these instances, since the collet 20' is mo~ed leftward, the work A is caused to abuts against the stopper 22' and the axial movement of .
the work A is prevented during Dachining operation. It will be appreciated~
that in the above noted modification the work A is held in a fixed position by the collet and the stationary rod whereby the occurrence of 20 off-centering o~ the work A i5 gatisfactorlly preventedO In addition, since the collet 20' is moved relative to the stationary rod fixedly supported by the flange body during mounting of the work A onto ~he chuck, the work A i9 fixed in a correct position at all times in an easy manner.
This illustrated modification can be utilized for automation of the machining 25 operatlon in which the work is fed to the position in front of the stopper "; ~; ,, " ,, ~ ";
. . . . . . . ... . . . . .
22' from an upper side of the collet chuck 10' before machining and the work is discharged downward after completion of the machining operation.
Fig. 5 shows another modification of a collet 20". In this modification, the collet 20" has an axial extension 40 contiguous with the chuck portion 20"c. As shown in Fig. 5~b~, each of the slits 29"
jpartially is formed in the collet 20" and an end of the extension 40 is not split.
This type of collet is specifically advantageous in that it is suited for extremely high precision work such as grinding.
Tests have been conducted with the use of the prior art collet chuck and the collet chuck of the present lnvention and the test results for the machining precision in case of turning operation of a ring for a bearing with an outer diameter of 60 mm are compared in the following Table I:and Table II:
Table I:
,~
Degree o$ Precision (Tolerance) . . _ __ Prior Art (mm) Present Invention ~mm) Thickness deviation (A-s) 0.07 o.a3 .
Diametrical deviation (C-D) 0.05 0.02 Gradient (E-F) 0.04 0.02 Slant ~G) 0.06 0.03 Axial deviation (I-~ 0.06 0.03 Diametri~al diff. range 0.06 0.03 Axial diff. range 0.10 0.05 ~L~7365~ :
.
., .
.~ , Table II:
. . . ......... .
. _ .. _ . . , _ _ Process . ~dvantages and degrees attained by the present invention . in comparison with prior art Material Reduction o cutted area , per one work - ~ 0.1 mm . . . Reducea wearing rate of chuck 50 %
.~v . _ ' . . ~educed checking time period for 72 ~
watching to maintain preci~ion .
~urning - :
~10 ~ ~ Reduction in in~erlority rate~ 48 ~ . . . , .: : . ; i, ., , ~ , ~ . ! ;, . Reduction in working time bécaùsè of ;` ~
_ po.~sible heavy cutting ~ ; ~ 30 % ;I .
. . . ~ Reduction in grinding time :"30 % : ~
. .. , . ~ , . ~ ~ .
Grinding ~ : :
. after. Reduced consumption of grinding : `~ ;~
1 turning ~ wheel and power, etc. ~ ~ 20 ~ .
; . ~ ~ . .~ , ~ , ~: ~;.; : .
' ~
', ', . ~ ' '' ~ '. ' .
~: :
' , ," ,, ' ~073~S~
:
It should be noted in Table I that the test results have been obtained by testing on 10,000 workpieces with a neglect,o dust adherence and wear of cutting tools, etc. It should also be noted that the characters ~, B, C... indicate the size of respective parts shown in Pig. 6.
It will be appreciated from the Table I ~hat`la~collet chuck in accvrdance with the present invention makes it possible to increase the working accuracy to a higher ex~ent since the degree of error in size of the machined workpiece held by the present collet chuck is about half that attained by the prior art collet chuck. As noted in Table II, further, since the area o~ the work to be cut i9 reduced in an actual machining operation, the cost for materials is reduced, and the inferiority rate , :
is reduced while attaining the reduction in working time.
It will thus be understood from the foregoing description that in accordance with the present invention the collet chuck is highly lS reliable in operation whereby a work can be accurately held in a correct ~;~ position in an ea=y fashion to perform high precision work and reduction .
in working costs.
While the present invention has been shown and described with reerence to particular embodiments by way o~ example, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention. For example, although the flange body of the collet chuck has been described as being applied to the lathe, the collet chuck of the present invention may be applied to any other =achi~ee such as gringlng mschines.
.
.
. . , This invention relates ~o collet chucks for lathes and, more particularly, to a draw-in-co,llet chuck adapted to oe used for high precision work in the lathe.
In prior art, it has been a common practice to use a ~
collet chuck to hold a ring-shaped work for machining. This type of chuck is usually composed of a collet screwed into a flange secured to a lathe, and an axially movable spindl~ wibh its ena formed with a tapered nose adapted bo be brought into engagement with a conical wall of the colleb whereby a holding portion of the collet is diametrically spread out, thareby firmly holding work. With this expedient, since the holding portion of the collet is frequently spread out by the action of the axially movable spindle and subjected to alternating load during machining operation, the colleb is caused to deflect so that the workpiece is held in an oI'f-centered posi-tion. In this case, it is difficult to perform high precision work. In the collet chuck of the type noted above, further, since the workpiece is caused to abut against the stop or annular shoulder . .
of the collet by the worker;~s hand and, under this condition, the collet .
is spread out, the worker bends to release his hand-away ~om the workpiece ~ before it is completely chucked by the collet with a resultant inaccurate ; 20 holding o~ the workpiece.
It is, therefore, an object of the present in~en-tion to provide a new and use~ul collet chuck which can overcomes the shortcomings encountered in the prior art.
It i9 another object of the present invention to provide a draw-in-collet chuck adapted to hold a workpiece in a highly reliable ,. . .
. ~.
,.
.
107365~
manner.
It is another o~ject of the present invention to provide a draw-in-collet chuck adapted to hold a workpiece in an on-center position during machining operation for thereby allowing high precision work.
i~ It is still another oBject of ~he present invention to prov~de a draw-in-collet chuck which is rigid in construction, easy to manipulate, and ready to be installed in anylkind of existing lathes.
It is a further object of the present invention to proYide a draw-in-collet chuck which is simple in construction and low in manufacturing cost.
In accordance with one broad aspect, the invention relates to a draw-in-collet chuck comprising: a flange body adapted to be mounted on a machine and including a hub extending axially from the flange body; a stationary rod fixedly supported by said flange body in concentric relation therewith, said stationary rod including a taperad nose provided at one end of the rod; a collet axially movable in concentric relation with said stationary rod and including a chuck portion circumferentially divided into several pieces to allow an outer diameter of the chuck portion to vary, and a taper hole formed inside of said collet at a position opposite to said tapered nose; and a s~opper mounted on said hub of said flange body to limit an axial movement of a work held by said chuck portion; said taper hole being engageable with said tapered nose of said stationary rod when said collet is moved toward said stationary rod, whereby the outer diameter of the chuck portion is increased so that the chuck portion of the collet is brought into pressured contact with an inner periphery of the work and the face of the work is pressured contact with said stopper; and wherein said stopper is mounted ,~, 1;
~ 3 _ )736Sl on said hub ~y means of an axially movable adjustment guide whereby the position of the stopper can be adjusted.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a partially cut-away view of a draw-in-collet chuck according to the present invention ~ ig. 2 is a cross-sectional view taken on line II~
; 10 of Fig. l;
Fig. 3 is an exploded view of the collet chuck shown in F~g. l;
Fig. 4 is a cross-sectional view showing a modified form of the collet chuck shown in Fig. 1;
Fig. S is a cross-sectional view showing another modifica~ion of the collet chuck shown in Fig. l; and Fig. 6 ~s a view illustrating the size of each paxt of a work.
Referring now to Figs. 1 to 3 of the drawings, there is , 2Q shown a preferred embodiment of a draw-in-collet chuck embodying the present invention. The collet chuck, generally designated as 10, comprises a flange 1 - 3a -, .. . .
~07365~
, body 12 adapted to be mounted on a lathe 14, a draw-in member 16, a s-tationary rod or sha~t 18 ~ixedly supported by the flange body 12 wi~h the end being formed with a tapered nose 18a, an axially movable collet - 20 adapted to hold a work A, and a stopper 22 serving as a means for engaging with and limiting the face of the work A.
The flange body 12 has a hub 12a axially extending ~rom -the flange bodyO The hub 12a is formed at its inner p0riphery with a threaded portion 24 and a tapered bore 26, -to which tapèred portions 18b radially extending ~rom the stationary rod 18 are ~itted. Threaded portions 18c o~
the stationary rod 18 screws into the -threaded portion 24 o~ the hub 12a and, thus, the stationary rod 18 is held stationary by the hub 12a. As best shown in Figs. 2 and 3, the circum~erentially divided tapered portions 18b of the stationary rod 18 de~ine sector spaces 18d, through which a circumferentially divided sleeve portion 16a o~ the draw-in member 16 extends toward the collet 20. The le~tward end of the draw-in ; member 16 is threaded as at 16c, to threadably accommodate therein a connecting rod (not shown) which i~terconnects the draw-in member 16 .
to a piston rod (not shown) o~ a hydraulic cylinder. Thus, the draw-in member 16 is movable in an axial direction togebher with the piston rod o~ the hydraulic cylinder. The sleeve portion 16a o~ the Araw-in member 16 is threaded at its end, which screws into one end of the collet 20.
In this manner, the draw-in member 16 is interconnected with the collet 20 and axially movable therewith,relative to the stationary rod 18. The collet 20 has a cylindrical section 20a slidably received in an inner bore 27 o~
the hub 12a. As shown in Pig. 3, the cylindrical section 20a has on its .
.... . .. . . .. . .. . . . . . .. . ... . ..
~a~736S~L
outer periphery an axially extending slot 28, with which an end of guide screws 30 screwed into the hu~ 12a engages to prevent rotation of the collet 20 relative to the hub 12a.
As shown in Fig. 3, the collet 20 also has a tapered section 20b and a chuck portion 20c which is circumferentially d~vided by slits 29 to provide three sectors adapted to engage with an inner wall of the work A as shown in Fig. 1. The chuck portion 20c has a taper hole 32 with which the tapered nose 18a o the stationary rod 18 engages, spreading the chuck portion 20c outward when the collet 20 is moved leftward as viewed in Fig. 1 by the action of the draw-in ~em~er 16. Indicated as 34 is an axial projection which is provided for machining the outer periphery of the chuck portion 20c in conormity with the inner periphery of the work A. To this end, a ring tnot shown) i~ placed onto the axial projection 34 to prevent the chuck portion 20c from being spread outward and, thereafter, the chuck portion 20c is applied with spreading force by the action of the draw-in member 16. Under this condition, the outer periphery of the chuck portion or section 20c is machined. During this machining, since the stationary rod 18 is held stationary by the flange body 12 and the taper hole 32 of the chuck section 20c is caused to engage with the tapered nose 18a of the rod 18 by the action of the draw-in member 16, the outer periphery of the chuck section 20c is accurately centered after it has been worked. It should be noted that while the tapered nose 18a has been shown and described with reference to an example in which it engages with the taper hole 32 the taper hole 34 may be replaced with a straight hole with which the nose 18a may engage.
The collet chuck constructed as mentioned above will operate in _ 5 _ 1~7365~ .
: .
the following manner:
The work A with its inner diameter machined in a given size is placed over the chuck portion 20a of the collet 20 as shown in Fig. 1.
Next, the hydraulic cylinder is actuated to cause the piston rod to draw the draw-in member 16 leftward as viewed in Fig. 1, moving the collet 20 in the same direction. In this instance, the nose 18a of the stationary rod 18 engages with the taper hole 32 o~ the chuck portion 20c, which is consequently spread outward with the increase ln its outer diameter.
Therefore, tha outer periphery of -the chuck portion 20c engages with the inner periphery o~ the work A. During le~tward movement o~ the colle-k 20, the work A is pulled in the same direction as the collet 20 a~ter it has engaged with the work A, 90 the work 1 is moved leftward and abuts against the s-topper 22 by which the work A is axially positioned. The work is held or maintained in a fixed position under the above-noted condition and, hence, , 15, axial movement of the work is prevented in a reliable manner during machining opratio~. Thus, the outer perlphery and face of the work A can - be easily machined in a high precision. After machining operation has ceased, the work A is removed from the chuck 10 by moving the dra~-in member 16 and ~ .
accordingly the collet 20 rightward in ~ig. 1. It will be seen in Fig. 1 that tho stopper 22 is conneoted to an adjustment guide 36 which is threaded over the hub 12 and axially movable to effect positioning o~ the stopper with respect to the work A. Indicated at 38 is a lock nut which, when the adjustment guide 36 is positioned bo a given location, is turned to lock the adjustment guide 36.
It will now be appreciated from tha foregoing description that ' ~G~7365~ `
in accordance with the present invention since the work A is supported by both o~ the stationary rod 18 and the collet 20 coi~cting with each other, the work A is satis~actorily preventea ~rom being o~ centered during heavy work or load. This is ensured by the hub 12a ~f the flange body 12 which is highly ~igid in constructio?n. Since~ further~ the work A is positioned by moving the collet 20 rela-tive to the stationi~ry rod 18 ~ixedly suppo~ted by the hub 12a in coaxial relationship with one another, the work A iisi highl~ reliably fix~??d in ~n-center position. Since the prior art collet chuck has a collet i~e`d to a flange body and adapted to spread by the action of a movable spindle whereby the work is supported, the collet i5 caused to deflect from its center line duriug machining operation of a lathe. During mounting of the work onto the collet, the movable spindle fits the collet to spread the same under a condition in which the collet is off-centered. It is thus difficult to adjust the collet to an on-center position and high precision work can not be obtained in a reliable manner. In the present invention, on the contrary, since the collet is brought to an on-center position by the tapered nose o the .
stationary rod and the work i9 adapted to be supported by both of the collet and the stationary support during machining operation, no o~f-centering of the collet is caused and high precision work can be attained for a long period of time.~
Fig. 4 shows a modified form of the collet chuck shown in Figs.
1 to 3, with like parts bearing the same reference numerals as those used in ~i~ .
Figs. 1 to 3 except that a single prime ~') has been added to~the~numeral indi~ative of a modified element. In Fig. 4, the stopper 22' is directly ., , . .
screwed into the hub 12a o~ the flange body (no$ sh~wn) and the collet 20' is held by a holder (not shown) at a position in front of the flange body.
The collet 20' has a plurali~y of slits 29' to permit radial deflec~ion of the chuck portion 20'c. The holder is arranged to be movable along a S path ~para~lel~ to:l~ the axls of the stationary rod 18 fixedly supportedby the flange body so that the collet 20' is movable in concentric with the stationary rod 18.
With~the above arrangement, the work A is placed in front of the stopper 22' and, subsequently, the collet 20' is moved leftward as ~iewed in Fig. 4 so that the collet portion 20'c goes through the work A.
/further When the collet 20' is moved leftward, ~he taper hole 32' engages with the tapered nose 18a of the stationary rod 18 by which the chuck portion 20'C 18 spread outward and the outer periphery;of~the;chuck portion 20'c is brought into pressured contact with the inner periphery of the work A.
In these instances, since the collet 20' is mo~ed leftward, the work A is caused to abuts against the stopper 22' and the axial movement of .
the work A is prevented during Dachining operation. It will be appreciated~
that in the above noted modification the work A is held in a fixed position by the collet and the stationary rod whereby the occurrence of 20 off-centering o~ the work A i5 gatisfactorlly preventedO In addition, since the collet 20' is moved relative to the stationary rod fixedly supported by the flange body during mounting of the work A onto ~he chuck, the work A i9 fixed in a correct position at all times in an easy manner.
This illustrated modification can be utilized for automation of the machining 25 operatlon in which the work is fed to the position in front of the stopper "; ~; ,, " ,, ~ ";
. . . . . . . ... . . . . .
22' from an upper side of the collet chuck 10' before machining and the work is discharged downward after completion of the machining operation.
Fig. 5 shows another modification of a collet 20". In this modification, the collet 20" has an axial extension 40 contiguous with the chuck portion 20"c. As shown in Fig. 5~b~, each of the slits 29"
jpartially is formed in the collet 20" and an end of the extension 40 is not split.
This type of collet is specifically advantageous in that it is suited for extremely high precision work such as grinding.
Tests have been conducted with the use of the prior art collet chuck and the collet chuck of the present lnvention and the test results for the machining precision in case of turning operation of a ring for a bearing with an outer diameter of 60 mm are compared in the following Table I:and Table II:
Table I:
,~
Degree o$ Precision (Tolerance) . . _ __ Prior Art (mm) Present Invention ~mm) Thickness deviation (A-s) 0.07 o.a3 .
Diametrical deviation (C-D) 0.05 0.02 Gradient (E-F) 0.04 0.02 Slant ~G) 0.06 0.03 Axial deviation (I-~ 0.06 0.03 Diametri~al diff. range 0.06 0.03 Axial diff. range 0.10 0.05 ~L~7365~ :
.
., .
.~ , Table II:
. . . ......... .
. _ .. _ . . , _ _ Process . ~dvantages and degrees attained by the present invention . in comparison with prior art Material Reduction o cutted area , per one work - ~ 0.1 mm . . . Reducea wearing rate of chuck 50 %
.~v . _ ' . . ~educed checking time period for 72 ~
watching to maintain preci~ion .
~urning - :
~10 ~ ~ Reduction in in~erlority rate~ 48 ~ . . . , .: : . ; i, ., , ~ , ~ . ! ;, . Reduction in working time bécaùsè of ;` ~
_ po.~sible heavy cutting ~ ; ~ 30 % ;I .
. . . ~ Reduction in grinding time :"30 % : ~
. .. , . ~ , . ~ ~ .
Grinding ~ : :
. after. Reduced consumption of grinding : `~ ;~
1 turning ~ wheel and power, etc. ~ ~ 20 ~ .
; . ~ ~ . .~ , ~ , ~: ~;.; : .
' ~
', ', . ~ ' '' ~ '. ' .
~: :
' , ," ,, ' ~073~S~
:
It should be noted in Table I that the test results have been obtained by testing on 10,000 workpieces with a neglect,o dust adherence and wear of cutting tools, etc. It should also be noted that the characters ~, B, C... indicate the size of respective parts shown in Pig. 6.
It will be appreciated from the Table I ~hat`la~collet chuck in accvrdance with the present invention makes it possible to increase the working accuracy to a higher ex~ent since the degree of error in size of the machined workpiece held by the present collet chuck is about half that attained by the prior art collet chuck. As noted in Table II, further, since the area o~ the work to be cut i9 reduced in an actual machining operation, the cost for materials is reduced, and the inferiority rate , :
is reduced while attaining the reduction in working time.
It will thus be understood from the foregoing description that in accordance with the present invention the collet chuck is highly lS reliable in operation whereby a work can be accurately held in a correct ~;~ position in an ea=y fashion to perform high precision work and reduction .
in working costs.
While the present invention has been shown and described with reerence to particular embodiments by way o~ example, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention. For example, although the flange body of the collet chuck has been described as being applied to the lathe, the collet chuck of the present invention may be applied to any other =achi~ee such as gringlng mschines.
.
.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A draw-in-collet chuck comprising:
a flange body adapted to be mounted on a machine and including a hub extending axially from the flange body;
a stationary rod fixedly supported by said flange body in concentric relation therewith, said stationary rod including a tapered nose provided at one end of the rod;
a collet axially movable in concentric relation with said stationary rod and including a chuck portion circumferentially divided into several pieces to allow an outer diameter of the chuck portion to vary, and a taper hole formed inside of said collet at a position opposite to said tapered nose; and a stopper mounted on said hub of said flange body to limit an axial movement of a work held by said chuck portion;
said taper hole being engageable with said tapered nose of said stationary rod when said collet is moved toward said stationary rod, whereby the outer diameter of the chuck portion is increased so that the chuck portion of the collet is brought into pressured contact with an inner periphery of the work and the face of the work is pressured contact with said stopper; and wherein said stopper is mounted on said hub by means of an axially movable adjustment guide whereby the position of the stopper can be adjusted.
a flange body adapted to be mounted on a machine and including a hub extending axially from the flange body;
a stationary rod fixedly supported by said flange body in concentric relation therewith, said stationary rod including a tapered nose provided at one end of the rod;
a collet axially movable in concentric relation with said stationary rod and including a chuck portion circumferentially divided into several pieces to allow an outer diameter of the chuck portion to vary, and a taper hole formed inside of said collet at a position opposite to said tapered nose; and a stopper mounted on said hub of said flange body to limit an axial movement of a work held by said chuck portion;
said taper hole being engageable with said tapered nose of said stationary rod when said collet is moved toward said stationary rod, whereby the outer diameter of the chuck portion is increased so that the chuck portion of the collet is brought into pressured contact with an inner periphery of the work and the face of the work is pressured contact with said stopper; and wherein said stopper is mounted on said hub by means of an axially movable adjustment guide whereby the position of the stopper can be adjusted.
2. A draw-in-collet chuck according to claim 1, further comprising a draw-in member connected to said collet and axially movable therewith.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA285,382A CA1073651A (en) | 1977-08-24 | 1977-08-24 | Draw-in-collet chuck |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA285,382A CA1073651A (en) | 1977-08-24 | 1977-08-24 | Draw-in-collet chuck |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073651A true CA1073651A (en) | 1980-03-18 |
Family
ID=4109398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA285,382A Expired CA1073651A (en) | 1977-08-24 | 1977-08-24 | Draw-in-collet chuck |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1073651A (en) |
-
1977
- 1977-08-24 CA CA285,382A patent/CA1073651A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |