QUICK CHANGEABLE COLLET CLAMPING ASSEMBLY

TECHNICAL FIELD

The present invention relates to a manual and/or automatic quick-change clamping assembly for releasably securing a collet to a turning machine or any other type of machine tool, and is more particularly related to a clamping assembly having a collet adapter with an expansion sleeve removably disposed therein and having a clamping portion thereon and with a draw pin extending through a bore in the expansion sleeve so that a portion of the draw pin engages the expansion sleeve causing radially outward movement of the clamping portion in response to axial displacement of the draw pin relative to the expansion sleeve, to releasably secure a collet in the collet adapter.

The present invention is further directed to an extraction tool for removing the collet from the clamping assembly.

BACKGROUND OF THE INVENTION

A collet is a device having two or more “jaws” between which an object such as a tool or a workpiece can be positioned. The jaws form a collar around the object. The jaws of the collet are configured to constrict around the object by deflecting radially inward. The jaws may be deflected radially inward by pushing a suitable mechanism (e.g., a collet adapter) around the circumference of the collet. In another type of collet called a draw-in collet, the collet is tapered and drawn into a sleeve (e.g., a collet adapter) by a draw bar to cause the jaws to constrict around the tool or workpiece. Collets are typically fabricated from steel, which allows the jaws to be sufficiently flexible relative to each other to allow the jaws to flex and hold the tool or workpiece.

The collet is held in a clamping device (e.g., a collet adapter and draw bar), which is connected to a shaft that can be rotated, which in turn causes the tool or the workpiece to rotate. In instances in which a tool is clamped in the collet and rotated, the tool is made to engage or be engaged by a workpiece. In instances in which the workpiece is clamped in the collet and rotated, the workpiece engages or is engaged by a tool.

Set-up and changing the collet usually are made manually and the set-up time often is considered being too long. Also, the set-up of the collet always requires a manual intervention of the operator and this stops production in the unmanned shift. Typically, the collet is screwed on a drawbar and angularly oriented with a pin. Often, this pin has to be taken away for screwing the collet on the drawbar, and then put back at its place in the collet adapter. This procedure isn't user-friendly and the collet may get damaged when putting the pin back in the keyway.

Thus, there is a need for an improved connection allowing a quicker and easier manual set-up time and/or an automatic set-up of the collet.

The rotational accuracy of the tool or the workpiece affects the process of removing swarf (e.g., metal chips) from the workpiece. In particular, the rotational accuracy of the tool or the workpiece is typically a function of concentricity along the axis of rotation. The concentricity achieved with mechanical clamping is often inadequate or compromised during rotation, thereby resulting in run-out. Such run-out can detrimentally affect the finished workpiece. Multiple cycles of operation of the pulling device can cause the concentricity to change for each cycle, thereby causing an inconsistent and unacceptable run-out accuracy.

The collet is removably attached to the draw bar by a suitable fastener. However, there is typically a gap on the guiding diameter between the collet and the collet adapter. This gap causes variation of concentricity between the collet and the rotation axis due to different reasons, such as variation of friction in the clamping system of the machine tool, variation of clamping force, such as pressure, direction, pulsation, vibrations, machining forces or other external influences on the tool or the workpiece, different angular orientation of the spindle between different clamping cycles, influence of dust, chips, wear and temperature.

Thus, there is a need for an improved connection between the collet and draw bar and an enhanced holding and guiding of the collet in the collet adapter. Also there is a need for an automatic procedure to load and extract the collet.

SUMMARY OF THE INVENTION

According to aspects illustrated herein, there is disclosed a clamping assembly for releasably clamping a collet. The clamping assembly includes a collet adapter and an expansion sleeve movably disposed in collet adapter. The clamping assembly includes a draw pin movably disposed in the expansion sleeve. The expansion sleeve cooperates with the draw pin to define a containment system configured maintain the expansion sleeve within an axial envelope and a radial envelope within the collet adapter. Axial movement of the draw pin in the expansion sleeve within the axial envelope causes a portion of the expansion sleeve to expand radially outward to a predetermined maximum diameter to releasably clamp the collet in the collet adapter.

According to aspects illustrated herein, there is provided a clamping assembly (100) for releasably clamping a collet (500), the clamping assembly (100) including a collet adapter (600) having a first interior surface (601, 602, 603, 604, 606, 607, 609, 610) defining a first bore (600B) concentric about a longitudinal axis (A), the first bore (600B) extending from a collet loading end (600C) to a draw bar receiving end (600A) of the collet adapter (600); an expansion sleeve (400) removably disposed in the first bore (600B) and in sliding engagement with a portion of the first interior surface (601, 602, 603, 604, 606, 607, 609, 610), the expansion sleeve (400) having a second interior surface (402, 409) defining a second bore (400B) extending between a first end (401) and a second end (408) thereof, the expansion sleeve (400) having a first exterior surface (403, 404, 405, 406, 407, 410) extending therearound and the expansion sleeve (400) having a portion of the first exterior surface defining a tapered clamping portion (403) proximate the first end (401) thereof; and a draw pin (300) removably disposed at least partially in the second bore (400B), the draw pin (300) having a second exterior surface (301, 302, 303, 305, 306307, 308, 311), wherein a portion (305) of the second exterior surface engages a portion of the second interior surface (402) of the expansion sleeve (400) causing radially outward movement of the clamping portion (403) in response to axial displacement of the draw pin (300) relative to the expansion sleeve (400).

In one embodiment, the expansion sleeve (400) includes two or more slots each of which extend along an axial length of the expansion sleeve and extend axially inward from the first end (401) and/or the second end (408).

In one embodiment, the clamping portion (403) includes a first axial leg (413A, 413B) and a second axial leg (413C, 413D). The first axial leg and the second axial leg are separated circumferentially by a first axial slot (412) and a second axial slot (412). Each of the first axial slot and the second axial slot extend axially inward from the first end (401). The first axial slot and the second axial slot impart flexibility to the clamping portion (403) so that the first axial leg and the second axial leg flex radially in response to the axial displacement of the draw pin (300) relative to the expansion sleeve (400).

In one embodiment, the clamping portion (403) includes a tapered surface.

In one embodiment, the expansion sleeve (400) includes a third axial leg (414A, 414B) and a fourth axial leg (414C, 414D). The third axial leg and the fourth axial leg are separated circumferentially by a third axial slot (411) and a fourth axial slot (411). Each of the third axial slot and the fourth axial slot extend axially inward from the second end (408). The third axial slot and the fourth axial slot impart flexibility to the expansion sleeve (400) so that the third axial leg and the fourth axial leg flex radially in response to the axial displacement of the draw pin (300) relative to the expansion sleeve (400).

In one embodiment, the collet adapter includes a first containment feature and the expansion sleeve includes a second containment feature. The first containment feature engages the second containment feature to releasably contain the expansion sleeve in the first bore and to limit axial movement of the expansion sleeve in the first bore to a predetermined distance (603L).

In one embodiment, the first containment feature includes a circumferential groove (603) extending radially outward from the interior surface (601) to a depth (603D) and the second containment feature comprises a circumferential tab (406) that extends radially outward from the expansion sleeve a height (406H) to limit radial expansion of a portion of the expansion sleeve to a predetermine magnitude established to prevent plastic deformation of the expansion sleeve.

In one embodiment, the circumferential groove (603) includes a first taper (604) on a side thereof to facilitate installation and removal of the expansion sleeve in the collet adapter.

In one embodiment, the circumferential tab (406) includes a second taper (405) to facilitate installation and removal of the expansion sleeve in the collet adapter.

In one embodiment, the draw pin (300) includes a taper (305) on the second exterior surface. The taper is configured to urge the clamping portion (403) radially outward to secure the collet in the collet adapter.

In one embodiment, the draw pin (300) includes a circumferential shoulder (306) on the second exterior surface to retain the clamping portion (403) radially outward to secure the collet in the collet adapter.

In one embodiment, one of the first axial slot (412) and the second axial slot (412) extend into one of the third axial leg (414A, 414B) and the fourth axial leg (414C, 414D). In one embodiment, one of the third axial slot (411) and the fourth axial slot (411) extend into one of the first axial leg (413A, 413B) and the second axial leg (413C, 413D).

According to aspects illustrated herein, there is provided a collet extraction tool (700) for extracting a collet from a collet adapter, the extraction tool including one or more latches (701) for releasably grasping the collet.

In one embodiment, the collet extraction tool is a castellated tube having two or more legs (703L) that extend from a ring (703R) portion of the tube. Adjacent pairs of the legs are spaced apart by a respective slot (703). The latch includes a circumferential groove (701G) that extends around an inner surface of the tube. The circumferential groove is configured to receive a lip (509L) extending around an exterior surface of the collet.

In one embodiment, the groove (701) has one or more axial lands (702) configured to engage a portion of the collet. Any of the foregoing embodiments may be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the Figures, which are exemplary embodiments, and wherein the like elements are numbered alike:

FIG. 1 is a perspective view of the clamping assembly of the present invention shown in the clamped position with the collet, the collet adapter and the draw bar;

FIG. 2 is a perspective view of the clamping assembly of FIG. 1 an extracting position with a collet clamped therein, a draw bar connected thereto and a collet extraction tool arranged to extract the collet from the collet adapter;

FIG. 3 is a cross sectional view of the clamping assembly of FIG. 1 shown in the extracting position with a collet, a collet adapter, a draw bar, a draw pin, an expansion sleeve and the collet extraction tool;

FIG. 4A is a cross sectional view of the clamping assembly of FIG. 1 shown in the clamping position with the collet, the collet adapter, the draw bar, the draw pin and the expansion;

FIG. 4B is a cross sectional view of the clamping assembly of FIG. 1 shown in the clamping position with the collet, the collet adapter, the draw bar, the draw pin and the expansion;

FIG. 5 is a cross sectional view of the clamping assembly of FIG. 1 shown in the unclamped position with the collet, the collet adapter, the draw bar, the draw pin and the expansion sleeve;

FIG. 6 is a cross sectional view of the clamping assembly of FIG. 1 shown in an empty clamped position with the collet adapter, the draw bar, the draw pin and the expansion sleeve, but with the collet removed;

FIG. 7A is a perspective view of the draw pin;

FIG. 7B is a cross sectional view of the draw pin;

FIG. 8 is a perspective view of the expansion sleeve;

FIG. 9 is a perspective view of the collet;

FIG. 10 is a perspective view of the collet extraction tool;

FIG. 11A is an enlarged view of FIG. 5 illustrating the unclamped position; and

FIG. 11B is an enlarged view of FIG. 4A illustrating the clamped position.

DETAILED DESCRIPTION

As shown in FIGS. 1-3, some embodiments of the present disclosure are directed to a clamping assembly 100 including a draw bar 200, an expansion sleeve 400, a collet 500, and a collet adapter 600. FIG. 1 shows collet assembly 100 in a clamped position in which a clamping force is exerted on the collet 500 to hold the collet within the collet adapter 600. FIGS. 2 and 3 show the collet assembly 100 in an extracting position, where a collet extractor 700 is used to remove the collet 500 from the collet adapter 600, as is discussed in greater detail herein. The clamping assembly 100 does not employ any coil springs.

Referring to FIGS. 4A and 4B, the draw bar 200 includes a draw bar mounting portion 201 for connection to a translation device (not shown). The translation device is configured and positioned to provide an axial movement force, rotational movement force, or combinations thereof to the draw bar 200. The axial movement forces can be pushing forces or pulling forces. Axial pulling forces result in clamping of the collet 500 in place within clamping assembly 100. Similarly, axial pushing forces result in unclamping of the collet 500, enabling easier removal than when in the clamped position.

The draw bar 200 includes a draw bar coupling portion 202 for connection with a draw pin 300. A draw bar end face 203 is disposed axially opposite the draw bar mounting portion 201. The draw bar end face 203 is positioned to provide axial movement during unclamping. In one embodiment, the draw bar 200 includes a draw bar hex 204 positioned to enable easier application of rotation forces upon the draw bar 200, e.g., to tighten the draw bar 200 into or remove the draw bar 200 from the translation device.

Referring to FIGS. 4A-4B and 7A-7B, the draw pin 300 includes an exterior surface (301, 302, 303, 304, 305, 306, 307, 308, and 311). Specifically, the draw pin 300 includes a draw pin coupling portion 301. The draw pin coupling portion 301 is configured to interface with the draw bar mounting portion 202 and fixedly hold the draw bar 200 and draw pin 300 together. In one embodiment, the draw pin coupling portion 301 and the draw bar mounting portion 202 have complementary threaded areas. The draw pin includes a first draw pin face 302, which interfaces with the draw bar end face 203. Thus, axial pushing movement of the draw bar 200 is transmitted via the draw bar face 203 to the first draw pin face 302, resulting in axial pushing movement of the draw pin 300. Along the length of the draw pin 300, there is a first guiding diameter 303, a draw pin groove 304, a draw pin taper 305, a circumferential shoulder 306, and a third guiding diameter 308. A second draw pin face 307 is positioned between the circumferential shoulder 306 and the third guiding diameter 308. The third guiding diameter 308 helps maintain concentricity between the draw pin 300 and the collet 500. In one embodiment, the draw pin 300 includes a draw pin hexagonal shaped bore 309 extending into the draw pin 300 and positioned to receive a hexagonal shaped male driver to enable application of rotation forces upon the draw pin 300, e.g., to tighten the draw pin 300 into or remove the draw pin 300 from the draw bar 200. In one embodiment, the draw pin 300 includes a draw pin thread 310 that allows fixation of an end stop for a workpiece. A draw pin end face 311 is disposed axially opposite the draw pin coupling portion 301. The draw pin end face 311 is positioned to eject a workpiece, as is discussed in greater detail herein.

Referring now to FIGS. 4A-6, the collet adapter 600 includes a hollow body having a draw bar receiving end 600A, a collet loading end 600C, and a first bore 600B disposed therebetween, each concentric about the longitudinal axis A. The collet adapter 600 joins the collet 500 to a machine spindle, as well as keeps an expansion sleeve 400 in a predetermined position.

The collet adapter 600 includes a first inner surface defined by first adapter guiding diameter 601, groove stop face 602, circumferential groove 603, first taper 604, adapter guiding diameter 606, adapter lead-in taper 607, clamping taper 609, and adapter lead-in diameter 610. The first adapter guiding diameter 601, adapter guiding diameter 606, clamping taper 609, and adapter lead-in diameter 610 are positioned and configured to center other components of clamping assembly 100, e.g., the expansion sleeve 400, the collet 500, etc. The adapter lead-in taper 607 prevents frontal collision between the collet 500 and the collet adapter 600 while loading the collet 500. As is discussed in greater detail herein, the adapter guiding diameter 606 is sized and configured to receive collet 500 as is deflected by a clamping force. The adapter guiding diameter 606 also helps maintain concentricity of the collet 500 and the draw bar 200.

The circumferential groove 603 has a depth 603D and a length 603L, and is sized and configured to receive the expansion sleeve 400 as is discussed in greater detail herein. The collet adapter 600 includes a mounting portion 605 for joining the clamping assembly 100 to the machine spindle. In one embodiment, the collet adapter 600 includes an orientation pin (608), sized and configured to consistently orient the collet 500 and prevent rotational movement thereof, as is discussed in greater detail herein.

As shown in FIGS. 4A-6 and 8, a portion of the draw pin 300 is positioned within an expansion sleeve 400. The expansion sleeve includes a first end 401 which is located axially opposite a second end 408 with a second bore 400B therebetween. In one embodiment, the first end includes a lead-in taper 410, which enables easier loading of the collet 500 by limiting frontal collision (e.g., contact or engagement) between the collet 500 and the expansion sleeve 400, as is discussed in greater detail herein. The first end 401 is positioned to interface with second draw pin face 307. Thus, axial pulling movement of the draw pin 300 is transmitted via the second draw pin face 307 to the first end 401, resulting in axial pulling movement of the expansion sleeve 400. The second end 408 is positioned to interface with the draw bar end face 203. Thus, axial pushing movement of the draw bar 200 is transmitted via the draw bar face 203 to the second end 408, resulting in axial pushing movement of the expansion sleeve 400.

The expansion sleeve 400 is a flexible member that includes an interior surface including interior surfaces 402 and 409 and an exterior surface including a clamping portion 403, flange extraction face 404, second taper 405, circumferential tab 406, flange stop face 407, and sleeve lead-in taper 410. The interior surfaces 402 and 409 are configured to interface with the draw pin 300 and maintain concentricity therewith. The first guiding diameter 303 prevents the interior surface 409 from collapsing at the second end 408. The circumferential shoulder 306 prevents the interior surface 402 from collapsing at the first end 401. When the draw pin 300 is pushed further into clamping assembly 100, the circumferential shoulder 306 is moved beyond the first end 401, which is instead aligned with the draw pin groove 304. The reduced diameter of the draw pin groove 304 allows the expansion sleeve to collapse at the first end 401, enabling easier application or removal of a collet 500 from the first end 401. When the draw pin is subsequently pulled, the draw pin taper 305 guides the expansion of the first end 401 back to the circumferential shoulder 306.

The circumferential tab 406 is positioned within the circumferential groove 603 in the collet adapter 600. The interaction between the circumferential tab 406 and the circumferential groove 603 maintains the expansion sleeve 400 within the same general axial position within the first bore 600B, and further prevents the expansion sleeve 400 from radial over-expansion. The first guiding diameter 303 acts to maintain the circumferential tab 406 within the circumferential groove 603. The circumferential tab 406 has a length 406L and a height 406H, and includes the flange stop face 407, the second taper 405, and the flange extraction face 404. The flange stop face 407 is positioned to interface with the groove stop face 602. Thus, the flange stop face 407 limits axial pulling movement of the expansion sleeve 400 and also prevents damage to collet 500 via this limited movement. The second taper 405 is positioned to interface with the first taper 604. Thus, the second taper 405 limits axial pushing movement of the expansion sleeve 400. Thus, the expansion sleeve 400 cooperates with the draw pin 300 to define a containment system configured maintain the expansion sleeve 400 within an axial envelope and a radial envelope within the collet adapter 600. The axial envelope is defined by the length 406L of the circumferential tab 406 and axial length 603L of the circumferential groove 603. The radial envelope is defined by the height 406H of the circumferential tab 406 the radial expansion thereof being limited by the depth 603D of the circumferential groove 603. Axial movement of the draw pin 300 in the expansion sleeve within the axial envelope causes a portion of the expansion sleeve 400 (e.g., axial legs 413A, 413B, 413C and 413D) to expand radially outward to a predetermined maximum diameter to releasably clamp the collet 500 in the collet adapter 600.

However, when the draw pin 300 is taken out, the expansion sleeve 400 can collapse radially and the second taper 405 helps guide the now reduced diameter circumferential tab 406 around the first taper 604 for easier removal from the collet adapter 600. The flange extraction face 404 acts to detach the collet 500 during unclamping via axial pushing movement as is discussed in greater detail herein.

The expansion sleeve 400 includes a clamping portion 403. The clamping portion 403 is positioned to translate the axial movements into a clamping force by deflecting the collet 500 into the collet adapter 600, as is discussed in greater detail herein. The expansion sleeve 400 is disposed partially inside the collet 500 to impart forces from a position inside the collet 500. The expansion sleeve 400 includes one or more back slots 411 and one or more front slots 412 so that the diameter of the expansion sleeve is flexible. The slots 411 and 412 define axial legs 413 (413A, 413B, 413C, and 413D in FIG. 8) and 414 (414A, 414B, 414C, and 414D in FIG. 8). The expansion sleeve 400 includes a plurality of front axial legs 413 (413A, 413B, 413C, and 413D in FIG. 8). In one embodiment, the expansion sleeve 400 includes two front axial legs 413. In one embodiment, the expansion sleeve 400 includes five axial front legs 413. In one embodiment, the expansion sleeve 400 includes at least three front axial legs 413. The expansion sleeve 400 also includes a plurality of back axial legs 414 (414A, 414B, 414C, and 414D in FIG. 8). In one embodiment, the expansion sleeve 400 includes two back axial legs 414. In one embodiment, the expansion sleeve 400 includes five axial back legs 414. In one embodiment, the expansion sleeve 400 includes at least three back axial legs 414.

Referring to FIGS. 4A-4B, 5, and 9, the collet 500 is sized and configured to hold and position a workpiece in clamping assembly 100 via collet clamping diameter 510. Collet 500 includes collet slots 518 so that the collet is flexible enough to collapse radially when applying the clamping force to the workpiece.

The collet 500 includes a first end face 501 positioned to interface with the flange extraction face 404. As discussed above, the flange extraction face 404 acts to detach the collet 500 by abutting the first end face 501. This force and movement result in detachment of the first collet clamping taper 507 from the adapter clamping taper 609, enabling easier removal of the collet 500. The collet 500 includes an exterior surface including first collet lead-in taper 502, a first collet lead-in diameter 503, a collet lead-in groove 504, and a second collet lead-in diameter 505, which are sized and configured to make it easier to load the collet 500 into the collet adapter 600 and over the expansion sleeve 400. The second collet lead-in diameter 505 also provides alignment of the collet rotation axis with the rotation axis of the collet adapter if there is an angular deviation in between both, and helps keep the collet 500 concentric with the collet adapter 600 during installation of the collet.

The exterior surface of collet 500 also includes a collet guiding diameter 506 and a first collet clamping taper 507. The first collet clamping taper 507 further acts to center the collet 500 within the collet adapter 600. Deflection of the collet guiding diameter 506 is the result of axial movement the clamping portion 403 along the interior surface of the collet 500. The interior surface of the collet 500 includes first collet internal diameter 512, a second collet clamping taper 513, a second collet internal diameter 514, a second collet lead-in taper 515, and a third collet lead-in diameter 516. The first collet internal diameter 512, second collet internal diameter 514, and third collet lead-in diameter 516 help maintain concentricity between the collet 500. The second collet lead-in taper 515 eases installation of the collet 500 over the expansion sleeve 400 via interaction with sleeve lead-in taper 410.

As the clamping portion 403 is brought into contact with the second collet clamping taper 513, a radial force is exerted on the collet 500 which radially deflects the exterior surface of the collet 500. This radial force pushes the exterior surface of the collet 500, such as the collet guiding diameter 506, into the interior surface of the collet adapter 600, and clamps the collet 500 in place.

The collet 500 includes an orientation keyway 511 configured to align with the orientation pin 608 from the collet adapter 600. In one embodiment, the orientation keyway 511 includes a lead-in angle 519 (see FIG. 9) making it easier to align the orientation keyway 511 with the orientation pin 608.

Referring now to FIGS. 3, 4B, and 10, some embodiments of the present disclosure are directed to a collet extraction tool 700 allowing extraction of the collet 500 from the collet adaptor 600. The collet extraction tool 700 includes at least one latch 701 for gripping the collet 500. The latch 701 includes a circumferential groove 701G extending at least partially around an inner surface of the collet extraction tool 700. The circumferential groove is positioned and sized to interact with a collet extraction groove 509 and receive a lip 509L on the collet extraction groove 509. At least one axial land 702 is included to engage a portion of collet 500. In one embodiment, the axial land 702 interfaces with a collet stop face 517 on the collet 500, thus limiting axial movement of the collet extraction tool 700 when applied to the collet 500. Axially applied forces can then insert or remove the collet 500 from the first bore 600B. In one embodiment, the collet 500 includes an orientation keyway 508 to orient the collet extraction tool 700 on the collet 500 in similar fashion to orientation keyway 511 for orienting the collet 500 and the collet adapter 600.

The body of the collet extraction tool 700 is a castellated tube having a bore 705 and including at least two legs 703L extending from a ring 703R. The legs 703L are separated by slot 703, which makes the collet extraction tool 700 flexible enough to expand and contract radially, such when engaging and disengaging from the collet 500. In one embodiment, the collet extraction tool 700 includes one or more handles 704 making it easier to hold and manipulate the collet extraction tool 700.

As shown in FIG. 11A, the clamping assembly 100 is in an unclamped position. In the unclamped position the draw bar 200 displaces the draw pin 300 in the direction of the arrow Q1. In the unclamped position the axial legs 413A, 413B, 413C and 413D of the expansion sleeve 400 are in a relaxed state and can be collapsed radially inward by the collet 500 in the direction of the arrows F1 into the draw pin groove 304. In the unclamped position the draw bar end face 203 abuts the second axial end 408 of the expansion sleeve 400 and there is an axial gap D11 between first end 401 of the expansion sleeve 400 and the draw pin stop axial face 307. In the unclamped position the clamping portion 403 of the expansion sleeve 400 is not engaged with the clamping taper 513 of the collet 500 and the collet 500 can be removed from the collet adapter 600. In the unclamped position the circumferential shoulder 306 of the draw pin 300 is not engaged with the guiding diameter 402 of the expansion sleeve 400.

As shown in FIG. 11B, the clamping assembly 100 is in a clamped position. In the clamped position the draw bar 200 displaces the draw pin 300 in the direction of the arrow Q2. In the clamped position the axial legs 413A, 413B, 413C and 413D of the expansion sleeve 400 are in an expanded state and are extended radially outward in the direction of the arrows F2 away from the groove 304. In the clamped position the draw bar end face 203 is spaced apart from the second axial end 408 of the expansion sleeve 400 by an axial gap D10 and the first end 401 of the expansion sleeve 400 and the draw pin stop axial face 307 are abutted against each other. In the clamped position the clamping portion 403 of the expansion sleeve 400 is engaged with the clamping taper 513 of the collet 500 and the collet 500 is itself expanded. Expansion of the collet 500 by the clamping force eliminates the small gap between the collet guiding diameter 506 and adapter guiding diameter 606, securing the collet 500 in the collet adapter 600. This reduces dispersion of run-out and also centers more precisely the collet 500 in the clamped position. In the clamped position the circumferential shoulder 306 of the draw pin 300 is seated on the guiding diameter 402 of the expansion sleeve 400 to retain the axial legs 413A, 413B, 413C and 413D in the expanded state.

Removing the collet 500 from clamping assembly 100 includes pushing draw bar 200 forward through the collet adapter 600 and towards the collet loading end 600C. The draw bar 200 moves the draw pin 300 with it. The draw bar end face 203 is once again brought into abutting contact with second axial end 408, thus displacing the expansion sleeve 400. As the expansion sleeve 400 is displaced, the circumferential tab 406 is displaced in the circumferential groove 603. As the circumferential tab 406 is displaced towards the collet end face 501, it is ultimately abutted against the collet end 501 at flange extraction face 404 and provides a removing force to the collet 500 in the direction of the arrow Q1. The contact between the clamping portion 403 and the second collet clamping taper 513 is also removed by this axial movement, reducing the radial force exerted by the collet 500 on the collet adapter 600. The collet 500 is thus easier to remove from the first bore 600B.

The clamping assembly 100 allows for quick manual and/or automatic change-out or attachment out of collets 500.

While the present disclosure has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention will not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Table 1 provides a listing and description of element numbers including function and contact configuration. In particular, column 1 identifies the element number that is employed on one or more of FIGS. 1-11B; column 2 provides a description of the element number; column 3 identifies the functionality or purpose for the particular element; column 4 describes the clamping situation during which the element is employed, including extracting the collet 500, the clamped position (e.g., FIG. 11B), the unclamped position (e.g., FIG. 11A), and the empty configuration with the collet 500 removed from the collet adapter 600 (e.g., FIG. 6); column 5 identifies the contact type the element has with a mating component, including, bearing contact, fixed contact, guiding contact and a free arrangement with no contact; and column 6 identifies other element number which the element identified in column 1 contacts or interfaces with.

TABLE 1

1

4

6

Element
2
3
Clamping
5
Other element

No.
Description
Functionality
situation
Contact type
number

A
Longitudinal axis
Reference line

100
Manual and/or
Provides for quick change out of a collet
—
—
—

automatic quick-

change attachment

200
Draw bar
Transmit clamping force and axial movement
—
—
—

from the pulling device (not shown) to the draw

pin

201
Draw bar
Joining the draw bar to the pulling device
all
fixed
Pulling device

mounting portion

(not shown)

202
Draw bar coupling
Joining the draw bar to the draw pin 300
all
fixed
301

portion

203
Draw bar end face
Gives the axial position to the draw pin
Extracting
Bearing
302/408

according to the drawbar.
Clamped
Bearing
302

Pushes against the expansion sleeve 400 to
Unclamped
Bearing
302/408

liberate the collet when unclamping
Empty cl.
Bearing
302

204
Draw bar hex
Hex for tightening the draw bar 200 on the
all
free
—

pulling device

300
Draw pin
Transmit clamping force and a part of the axial
—
—
—

movement to the expansion sleeve

301
Draw pin coupling
Joining the draw bar 200 to the draw pin 300
all
fixed
202

portion

302
First draw pin stop
Gives the axial position to the draw pin 300
all
bearing
203

face
according to the draw bar 200

303
First draw pin
Guidance and centering of the expansion sleeve
all
guiding
409

guiding diameter
400 on the draw pin. This diameter prevents the

expansion sleeve 400 from collapsing at the first

end and prevents it from leaving the groove in

the collet adapter. When the draw pin 300 is

taken out of the dmw bar 200, the expansion

sleeve can collapse radially inward at the second

end and glide forwards. In this way, the

expansion sleeve 400 can be taken out of the

collet adapter 600.

304
Draw pin groove
Allows the expansion sleeve to collapse at the
all
free
—

first end while extracting or loading a collet 500.

305
Draw pin taper
Opens up the expansion sleeve 400 at the first
all
free
—

end while making the clamping or empty

clamping movement.

306
Second draw pin
Guiding and centering the draw pin 300 while
Extracting
free
—

guiding diameter
clamping the collet 500. Prevent the expansion
Clamped
guiding
402

sleeve 400 from collapsing at the first end in
Unclamped
free
—

clamped and empty clamped position
Empty
guiding
402

307
Second draw pin
Transmit clamping force and a part of the axial
Extracting
free
—

stop face
movement to the expansion sleeve 400.
Clamped
bearing
401

Unclamped
free
—

Empty
bearing
401

308
Third draw pin
Pre-centering (with gap) the draw pin 300 in the
all
free
—

guiding diameter
collet 500 in unclamped position

309
Draw pin
Hexagonal bore for tightening the draw pin 300
all
free
—

hexagonal bore
on the draw bar 200

310
Draw pin thread
Allows optionally to fix an end stop for the work
all
free
—

piece if needed.

311
Draw pin end face
Allows optionally to eject the work piece if
all
free
—

needed.

400
Expansion sleeve
Transmit clamping force and a part of the axial
—
—
—

movements to the collet 500. This flexible

element collapses on the first end when entering

or extracting the collet. When putting in the

expansion sleeve 400 in the adapter 600, the

expansion sleeve 400 collapses radially inward

before gliding in the groove. Because the

clamping force is transmitted over a taper, the

clamping force will expand the collet 500 to

eliminate the small gap between the guiding

diameter of the collet 500 and the collet adapter

600. This reduces dispersion of run-out and

centers more precisely the collet 500 in clamped

position.

401
First sleeve end
Transmit clamping force and a part of the axial
Extracting
free
—

face
movement from the draw pin 200.
Clamped
bearing
307

Unclamped
free
—

Empty
bearing
307

402
First sleeve
Guiding and centering the draw pin 200 while
Extracting
free
—

guiding diameter
clamping the collet 500. On the sulface defined
Clamped
guiding
306

by the first sleeve guiding diameter 402, the draw
Unclamped
free
—

pin 300 prevents the expansion sleeve 500 from
Empty
guiding
306

collapsing at the first end in clamped and empty

clamped position.

403
Sleeve clamping
Transmit clamping force and a part of the axial
Extracting
free
—

taper
movements to the collet 500. Because the
Clamped
bearing
513

clamping force is transmitted over a taper, the
Unclamped
free
—

clamping force will expand the collet 500 to
Empty
free
—

eliminate the small gap between the guiding

diameter of the collet 500 and the collet adapter

600. This reduces dispersion of run-out and

centers more precisely the collet 500 in clamped

position.

404
Flange extraction
Transmit unclamping force and movement to the
Extracting
free
—

face
collet 500. The Flange extraction face 404
Clamped
free
—

detaches the first collet clamping taper from the
Unclamped
bearing
501

adapter clamping taper when unclamping the
Empty
free
—

collet.

405
Flange stop taper
Stops the axial movement of the expansion
Extracting
bearing
604

sleeve 400 when unclamping and extracting the
Clamped
free
—

collet. When the draw pin 300 is taken out of the
Unclamped
bearing
604

draw bar 200, the expansion sleeve 400 can glide
Empty
free
—

forward and collapse radially inward at the

second end by following the groove stop taper. In

this way, the expansion sleeve 400 can be taken

out of the collet adapter 600.

406
Flange guiding
Pre-centering (with gap) the expansion sleeve
all
guiding
603

diameter or tab
400 in the collet adapter 600. Prevents the

expansion sleeve 400 from expanding in over its

nominal radial dimension.

406H
Height of tab 406
Prevents the expansion sleeve 400 from

expanding over its nominal radial dimension.

406L
Length of tab 406
Limits and establishes axial movement of the

expansion sleeve 400 in the collet adapter 600.

407
Flange stop face
Stops axial movement in empty clamping
Extracting
free
—

position and protects the collet 500 from damage.
Clamped
free
—

Unclamped
free
—

Empty
bearing
602

408
Second sleeve end
Transmit the unclamping force and a part of the
Extracting
Bearing
203

face
axial movement from the draw bar 200.
Clamped
free
—

The second sleeve end face 408 is used to detach
Unclamped
Bearing
203

the first collet clamping taper from the adapter
Empty
free
—

clamping taper when unclamping the collet.

409
Second sleeve
Guidance and centering of the expansion sleeve
all
guiding
303

guiding diameter
400 on the draw pin 300. This diameter prevents

the expansion sleeve 400 from collapsing at the

first end and prevents it from leaving the groove

in the collet adapter. When the draw pin 300 is

taken out of the dmw bar 200, the expansion

sleeve 400 can collapse radially inward at the

second end and glide forward. In this way, the

expansion sleeve 400 can be taken out of the

collet adapter.

410
Sleeve lead-in
Makes it easier to load the collet, prevents frontal
all
free
—

taper
collision between the collet and the expansion

sleeve 400 while loading the collet

Closes the expansion sleeve 400 on the first end

in contact with the second collet lead-in taper

(515) when loading the collet

411
Sleeve back slots
Makes the expansion sleeve 400 flexible enough
all
free
—

to collapse radially at the second end when put in

or take out the expansion sleeve 400 (assembly

without draw pin)

412
Sleeve front slots
Makes the expansion sleeve 400 flexible enough
all
free
—

to collapse radially at the first end, when loading

or extracting the collet

413A
Legs front sleeve
Extend outwardly to clamp collet 500.

413B

413C

413D

414A
Legs back sleeve
Extend outwardly to allow draw pin 300 to enter

414B

and the contracted assembly to releasably contain

414C

the expansion sleeve 400.

414D

500
collet
Transform the axial clamping force and
—
—
—

movement from the pulling device in a radial

clamping force and movement, clamping a work-

piece. Center the work piece according to the

rotation axis of the machine spindle.

501
Collet end face
Transmit unclamping force and movement from
Extracting
free
—

the expansion sleeve 400 to the collet. This force
Clamped
free
—

and this movement detach the first collet
Unclamped
bearing
404

clamping taper from the adapter clamping taper
Empty
free
—

when unclamping the collet.

502
First collet lead-in
Makes it easier to load the collet 500, prevents
all
free
—

taper
frontal collision between the collet 500 and the

collet adapter 600 while loading the collet 500 in

the collet adapter 600.

503
First collet lead-in
Makes it easier to load the collet 500. Pre-
all
free
—

diameter
centering (with gap) the collet 500 first in the

adapter lead-in diameter and second in the

adapter guiding diameter while loading the collet

500 in the collet adapter 600.

504
Collet lead-in
Makes it easier to load the collet 500 in the collet
all
free
—

groove
adapter 600. Prevents the collet 500 from

sticking in the collet adapter lead-in diameter if

there is an angular deviation between the rotation

axis of the collet adapter 600 and the collet 500.

505
Second collet
Makes it easier to load the collet 500 in the collet
all
free
—

lead-in diameter
adapter 600. Alignment of the collet rotation axis

with the rotation axis of the collet adapter 600 if

there is an angular deviation in between both.

Pre-centering (with gap) the collet first in the

adapter lead-in diameter and second in the

adapter guiding diameter while loading the

collet.

506
Collet guiding
Centers the collet 500 precisely in the collet
Extracting
free
—

diameter
adapter guiding diameter in clamped and
Clamped
guiding
606

unclamped position. There is still a very small
Unclamped
guiding
606

gap in between these two diameters,
Empty
free
—

characteristic for all draw-in collets with

cylindrical shank. If the collet is drawn back at

its back end, this gap gets bigger because the

collet guiding diameter constricts as a result of

the axial pulling force. In this invention, the gap

is eliminated through the clamping force in

clamped position, because the axial clamping

force is decomposed over the second collet

clamping taper (513) in an axial and a radial

force component. The radial force component

expands the collet guiding diameter radially

while clamping the collet. This increases

centering precision and makes run out dispersion

smaller.

507
First collet
Centers the collet 500 according to the collet
Extracting
free
—

clamping taper
adapter 600.
Clamped
bearing
609

Unclamped
free
—

Empty
free
—

508
First collet
Allows optionally to orientate the collet 500 in
Extracting
Free
—

orientation
the extractor 700.
Clamped
free
—

keyway

Unclamped
free
—

Empty
free
—

509
Collet extraction
Transmits the extracting movement from the
Extracting
bearing
701

groove
extractor 700 to the collet 500.
Clamped
free
—

Unclamped
free
—

Empty
free
—

509L
Circumferential
Seats in the groove 701G of the extraction tool

lip of the groove
700.

510
Collet clamping
Centers and holds the workpiece
Extracting
free
—

diameter

Clamped
bearing
Workpiece

Unclamped
free
—

Empty
free
—

511
Second collet
Orientation of the collet 500 in the collet adapter
Extracting
free
—

orientation
600, prevents the collet from rotating between
Clamped
guiding
608

keyway
different clamping/unclamping cycles.
Unclamped
guiding
608

Empty
free
—

512
First collet internal
Pre-centering (with gap) the draw pin 300 in the
all
free
—

diameter
collet 500 in unclamped position.

513
Second collet
Transmit clamping force and a part of the axial
Extracting
free
—

clamping taper
movements from the expansion sleeve 400.
Clamped
bearing
403

Because the clamping force is transmitted over a
Unclamped
free
—

taper, the clamping force will expand the collet
Empty
free
—

what eliminates the small gap between the

guiding diameter of the collet and the collet

adapter. This reduces dispersion of run-out and

centers more precisely the collet in clamped

position.

514
Second collet
Pre-centering (with gap) the draw pin in the
all
free
—

internal diameter
collet when loading the collet

515
Second collet
Closes the expansion sleeve 400 on the first end
all
free
—

lead-in taper
in contact with the sleeve lead-in taper (410)

when loading the collet

516
Third collet lead-
Pre-centering (with gap) the expansion sleeve
all
free
—

in diameter
400 in the collet when loading the collet

517
Collet stop face
Makes it easier to push the extractor 700 on the
all
free
—

collet 500. Stops the axial movement when

pushing the extractor 700 on the collet.

518
Collet slot
Makes the collet 500 flexible enough to collapse
all
free
—

radially when applying the clamping force.

519
Key way lead-in
Makes it easier to load the collet 500. This angle
all
free
—

angle
turns the collet when there is a misalignment

between the second collet orientation keyway

(511) and the orientation pin (608).

600
Collet adapter
Main body, joining the collet 500 to the machine
all
free
—

spindle. This part also keeps the expansion

sleeve 400 at its predetermined position.

600A
draw bar receiving
Portion of collet adapter to receive draw bar 200.

end of collet

adapter

600B
Through bore of
Cylindrical bore extending through collet adapter

collet adapter
600.

600C
collet loading end
Portion of collet adapter 600 for receiving and

of collet adapter
loading the collet 500.

601
First adapter
Pre-centering (with great gap) the draw bar 200
all
free
—

guiding diameter
in the collet adapter 600.

602
Groove stop face
Stops axial movement in empty clamping
Extracting
free
—

position and prevents the collet 500 from being
Clamped
free
—

damaged.
Unclamped
free
—

Empty
bearing
407

603
Groove diameter
Pre-centering (with gap) the expansion sleeve
all
guiding
406

400 in the collet adapter. Prevents the expansion

sleeve 400 to expand over its nominal radial

dimension,

603D
Depth of groove
Prevents the expansion sleeve 400 to expand

603
over its nominal radial dimension.

603L
Axial length of
Limits and establishes axial movement of the

groove 603
expansion sleeve in the collet adapter 600.

604
Groove stop taper
Stops the axial movement of the expansion
Extracting
bearing
405

sleeve when unclamping and extracting the
Clamped
free
—

collet. When the draw pin is taken out of the
Unclamped
bearing
405

draw bar, the expansion sleeve 400 can glide
Empty
free
—

forwards and collapse radially at the second end

by following the groove stop taper. In this way,

the expansion sleeve 400 can be taken out of the

collet adapter.

605
Adapter mounting
Joining the collet adapter 600 to the machine
all
fixed
Machine

portion
spindle.

spindle

606
Adapter guiding
Centers the collet 600 precisely on the collet
Extracting
free
—

diameter
guiding diameter in clamped and unclamped
Clamped
guiding
506

position. There is still a very small gap in
Unclamped
guiding
506

between this two diameters characteristic for all
Empty
free
—

draw-in collets with cylindrical shank. If the

collet is drawn back at its back end, this gap gets

bigger because the collet guiding diameter

constricts as a result of the axial pulling force. In

this invention, the gap is eliminated through the

clamping force in clamped position, because the

axial clamping force is decomposed over the

second collet clamping taper (513) in an axial

and a radial force component. The radial force

component expands the collet guiding diameter

radially while clamping the collet 500. This

increases centering precision and makes run out

dispersion smaller.

607
Adapter lead-in
Makes it easier to load the collet 500, prevents
all
free
—

taper
frontal collision between the collet 500 and the

collet adapter 600 while loading the collet 500.

608
Orientation pin
Orientation of the collet 500 in the collet adapter
Extracting
free
—

600, prevents the collet 500 from rotating
Clamped
guiding
511

between different clamping/unclamping cycles.
Unclamped
guiding
511

Empty
free
—

609
Adapter clamping
Centers the collet 500 according to the collet
Extracting
free
—

taper
adapter 600. Transforms the axial clamping force
Clamped
bearing
507

from the pulling device in a radial clamping
Unclamped
free
—

force to hold the work piece.
Empty
free
—

610
Adapter lead-in
Makes it easier to load the collet 500. Pre-
all
free
—

diameter
centering (with gap) the collet 500 first on the

first collet lead-in diameter, then on the second

collet lead-in diameter and finally, with a smaller

gap, on the collet guiding diameter.

700
Collet extractor or
This part allows to extract the collet form the
—
—
—

collet extraction
collet adapter.

tool.

701
Extractor nose
Transmits the extracting movement from the
Extracting
bearing
509

extractor to the collet 500.
Clamped
free
—

Unclamped
free
—

Empty
free
—

701G
Circumferential
Formed in an inner surface of the extraction tool

groove
tube for receiving the lip 509L of the collet 500.

702
Extractor end stop
Makes it easier to push the extractor on the
all
free
—

collet. Stops the axial movement when pushing

the extractor on the collet 500.

703
Extractor slot
Makes the extractor flexible enough to expand
all
free
—

radially when pushing the extractor on the collet

500.

703L
Extraction tool
Flexible legs separated by the slots 703 for

legs
releasably grasping the collet 500.

703R
Ring portion of
Continuous ring holds the legs 703L together as

extraction tool
one unitary piece.

704
handle
Place to hold manually the extractor 700.
all
free
—

705
Extractor through
Makes the extractor flexible enough to expand
all
free
—

bore
radially when pushing the extractor 700 on the

collet 500.

Allows to push the extractor 700 over the collet

nose.

QUICK CHANGEABLE COLLET CLAMPING ASSEMBLY

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims

CROSS REFERENCE TO RELATED APPLICATIONS

Provisional Applications (1)