Patent Application
20210107069
The invention relates to chucks or turning and particularly to chucks with simultaneously acting jaws and longitudinally split sleeves, e.g. collet chucks, with a tool or workpiece positioning stop. The invention also relates to chucks, an accessory or component thereof, and a tool or work stop or locator.
including information disclosed under 37 CFR 1.97 and 1.98—Collet chucks provide a mechanical connection on machine tools to carry a tool or a workpiece in proper position for cutting or forming. A basic collet is an axially extending tube with a flared front end where the tube wall is split into several axial fingers or jaws. The interior of the tube extending rearward from the flared front can be referred to as a capacity bore, since within the capacity of the collet this area receives a portion of a workpiece. The workpiece can be placed in the capacity bore of the tube on the central axis of the tube. At the rear of the capacity bore, the tube is precision threaded to receive a stop body with matching precision threads. The stop body is threaded into the rear of the capacity bore and grounded against the rear face of the collet, creating a fixed spatial relationship between the collet and the stop body. The stop body itself has a threaded axial bore that fits a threaded collet stop, which is advanced from the rear of the stop body, through the stop body, and into the capacity bore of the collet to a desired spacing behind the front of the collet. Once the collet stop is properly placed at the desired distance, a lock nut is threaded over the collet stop from the rear end and secured against the rear end of the stop body, thus locking the position of the collet stop with its front end in the desired placement behind the front of the collet.
In the operation of the machine tool, a compressing collar can then be drawn over the flare of the collet to compress the jaws against the workpiece, thus locking the workpiece concentrically in the collet. The collet is an interface between the workpiece and the machine tool. It not only holds the workpiece in a concentric position, but it holds the workpiece in a fixed axial extension from the front of the collet. In a typical example, the collet also engages the machine tool, such as on a rotary spindle, so that the machine tool can spin the workpiece with great precision about the central axis. A cutting or shaping element of the machine tool can then be applied to the portion of the workpiece extending axially forward from the collet. When the work is complete, the jaws are opened by withdrawing the compressing collar, and the workpiece is removed from the front end of the collet. Such collets are commonly used on lathes, milling machines, and the like.
Collets are available in a limited selection of different capacities and can be exchanged on a machine tool to fit the task at hand. Establishing a proper position between the collet and the carried tool or workpiece desirably is done with speed and accuracy. Particularly, when a single collet is in sequential use to make a series of identical workpieces, each workpiece must be positioned identically in the capacity bore of the collet to ensure that the completed workpieces are identical in length. To achieve this result, a collet is provided with a collet stop at a selected depth in the capacity bore so that each workpiece can be inserted identically, until it strikes the collet stop. Commensurately, whether a series of workpieces or a single workpiece require a particular depth to the collet stop, the process of accurately setting the stop must be accomplished with reasonable efficiency and precision. Thus, the most desirable characteristics of a collet stop are speed of precise initial setting and durability of a setting to remain accurate through repetitive uses.
Adjusting or transferring a collet stop even in the previously described basic collet is time consuming, which is a form of inefficiency and economic loss. An array of tools is needed to remove and reinsert a collet stop. Because the typical collet stop is threaded into place and locked by a lock nut, both the lock nut and the collet stop, itself, must be both loosened and withdrawn from the stop body to change size or axial position of the stop. These steps not only consume time but also wear on the threaded components. For example, grounding and ungrounding the stop body against the rear of the collet might wear both the threads and the grounded surfaces. Locking a locknut and then backing it off also has the capacity to wear on threads and wear on abutting surfaces.
A recent variation of the basic collet stop is shown in U.S. Pat. No. 5,772,219 to Vossen, which shows an outer clamping collet that contains an interior stop-adjusting mechanism. This mechanism employs a small, single ended, coaxial collet that fits in the capacity bore of the clamping collet. The small collet closely fits over a wide diameter center length of a complex stop-rod. A wide center length of the stop-rod is a mounting portion that can be moved axially in the small collet and gripped where necessary by the jaws of the small collet. The complex stop-rod also has a forward extension that is narrower in diameter than the wide center length. The narrow portion serves as the collet stop portion and is held at a selected axial position in the capacity bore. The available positions of the narrow extension are limited by the requirement that the wide center length is the only part of the stop-rod that the small collet can grip, which prohibits the stop-rod from forward placement beyond where the wide portion can be clamped in the jaws of the small collet. Accordingly, the narrow stop-rod must be placed primarily toward the front of the capacity bore. The small collet is fastened in the clamping collet near the rear of the capacity bore. It is held by a stop body that is threaded into the rear of the clamping collet and grounded against the rear of the clamping collet. A lock nut screws onto the rear of the small collet and pulls back the small collet within the stop body, causing the stop body to compress the jaws of the small collet to grip the wide center section of the stop-rod. Notably, the stop body can neither remain in one place nor move forward to compress the jaws of the small collet. Instead, the small collet must move backwards for the jaws to clamp on the stop-rod. This backwards movement of the small collect will introduce error into the resulting position of the stop-rod as it is clamped. The complex stop-rod also is a disadvantage because replacement rods must be custom fabricated, which adds undesirable expense and loss of time to jobs.
It would be desirable to have a collet stop assembly that can accommodate an extended range of stop elements.
It would be desirable to have a collet stop assembly that can be adjusted to different stop positions and sizes by substitution with standard size, widely available components.
It would be desirable to have a collet stop that can be changed quickly, such as, for example, a matter of seconds rather than a period of minutes that might be a substantial portion of an hour.
It would be desirable to have a collet chuck that enables changeover of a collet stop with ability to quickly and precisely establish a desired stop depth.
It would be desirable to employ a fastening system for a collet stop or stop-rod that retains the accuracy of a selected position while securing the collet stop in fixed position.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.
Against the described background, it is therefore a general object of the invention to provide a rapidly exchanged and accurate work stop member for a work-holding-collet.
According to the invention, a work-holding-collet is formed of: a body with flared front end defining a ring of compressible jaws around a central work-receiving collect mouth. A capacity bore is within the collet body, rearward of the flared front end. A work-stop body is releasably attached to the rear of the body of the work-holding-collet and defines a through passageway longitudinally aligned with the mouth of the work-holding-collet.
In a first embodiment, an internal stop-collet is carried for longitudinal movement with respect to the work-stop body, and the stop-collet also is carried in longitudinal alignment with the mouth. In use, the stop-collet can carry a work stop at a variably selected distance behind the mouth. The purpose of a work stop is to lie in the rear path of a workpiece being inserted into a work-holding-collet and to block such insertion at a predetermined depth of insertion. Thus, a work stop also accurately can be called as a depth stop. This component most commonly is embodied as a rod or pin. A work stop-rod or depth stop-rod has a front end that is contacted by the rear of a workpiece as it is inserted through the mouth and blocks further insertion of a workpiece. The stop-collet is mounted to an intermediate shank that is slidable in the axial passageway of the work-stop body, allowing the shank and stop-collet to move axially, placing the front end of the work stop-rod within the capacity bore at a selected spacing behind the collet mouth for, in use, blocking rearward extension of a workpiece inserted in the collet mouth. The work-stop body has an associated lock operable between the intermediate shank and the through passageway to secure the intermediate shank in a fixed position with respect to the passageway;
In a second embodiment, a work-holding-collet is adapted to handle the special problems of using a tee-square stop. This type of stop is characterized by a broad head on a considerably narrower shaft, thus resembling the letter “T” in side view. The narrower shaft can be accommodated in the internal stop-holding collet, while the broad head is of too large a diameter to fit the internal stop-holding collet. The problem that arises is that a small offset from perfect centering of the shank in the passageway of the work-stop body is translated into a wobble of the broad head of the tee-square stop. The solution is to proportion the passageway to have one or more centrally located setscrews centrally located from end to end. Preferably there are two spaced-apart setscrew locations in a central segment of the passageway with equal end segments of the passageway extending forward and rearward from the central segment. Thus, the equal forward and rearward segments of the passageway stabilize the shaft to turn on the centerline of the work-holding-collet and in good alignment with the spindle of the machine tool that eventually carries the work-holding-collet.
In a third embodiment, instead of carrying the shank, the passageway slidably carries a tube stop, which is a hollow tube structure with an open front end and a workpiece-blocking rear closure. The tube stop slides axially in the passageway for longitudinal displacement with respect to the mouth of the work-holding-collet, placing the rear end of the tube stop rearward of the work-stop body at a variably selected spacing behind the mouth of the work-holding-collet for, in use, blocking further rearward extension of a workpiece that has been inserted in the mouth of the work-holding-collet. The tube stop has an associated lock operable between the tube stop and the through passageway, securing the tube stop in a fixed longitudinal position with respect to the passageway.
According to a further aspect of the invention, where the stop-collet is present, the associated lock on the work-stop body is a setscrew applied through the work-stop body, into the passageway, and into contact with the intermediate shank. The intermediate shank defines a flat longitudinal edge that is positionable in the passageway to be the contact surface for the set screw.
Still further, the intermediate shank is adapted to cooperate with work stop-rods of different diameters. The shank contains a cavity that is suitable to receive stop-collets of a range of capacities, thereby adapting the work-holding-collet to operate with work stop-rods sized over a range of sizes.
According to another aspect of the invention, where a tube stop is used with the passageway, the associated lock applied to the tube stop is a setscrew applied through the work-stop body, into the passageway, and into contact with the tube stop. Because the wall of the tube stop may be less strong than the wall of a shank, the setscrews may engage the tube stop in a novel way. The wall of the tube stop is configured with multiple rows of reception holes in the tube wall, with reception holes of some rows being axially offset from others. The tube stop can be positioned for different reception holes to align with and receive the set screws.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with the description, serve to explain the principles of the invention. In the drawings:
The invention is an adaptive work-stop assembly that typically will be mounted at the rear of and partially inside a work-holding-collet during use. Another, smaller, internal collet will be referred to as the stop-collet. The latter is part of an embodiment of the work-stop assembly and fits within the work-holding-collet to hold a work stop-rod. Typically the work-holding-collet will be mountable on a rotary spindle of a machine tool. In the setup of a rotary machine tool, collets often are used to hold a tool that will he applied to a workpiece. In addition, collets often are used to hold a workpiece that a tool will be applied to in order to position the tool to shape the workpiece.
For convenience of description, the invention will be referred to as operating with a carried workpiece, with the defined meaning that a workpiece refers not only in one sense to an object being modified but also in a second sense to an object performing the modification commonly referred to as a tool. Precision placement of both is needed to setup a machine for automated operation. Opposed work-holding-collets can be selectively used to position both the conventional workpiece and the tool. In either or both usages, the work-holding-collet allows positional adjustment between a tool and the conventional workpiece so dial the tool and the conventional workpiece come together at a desired working relationship. Particularly, the work-holding-collet holding the workpiece or tool serves the additional function of being able to receive subsequent identical workpieces or tools at the same respective position as the initial workpiece or tool, so that the tool is applied at exactly the same position to a subsequently inserted conventional workpiece and produces an identical product from each subsequent conventional workpiece.
To achieve such a consistent result, the work-holding-collet and a selected work stop of the work-holding-collet should have an adaptable relationship such that when the selected work stop has positioned the workpiece, such as by axially locating the workpiece at a selected depth in line with the collet mouth, the work stop is not interfering with operation of the work-holding-collet. As a matter of efficient choice, each work stop should be adjustable within the work-holding-collet over the full useful range of available work stop positions so that there can be no accidental interference with the work-holding-collet.
A work stop-rod sometimes is a dual diameter rod, with a non-uniform lengthwise profile such as one end having relatively wider diameter and the other end a relatively narrower diameter. Where a non-uniform lengthwise profile is in use, an efficient choice may employ the narrower end to mount and carry the work stop-rod and the wider end to be the depth stopping end of the rod, rather than the opposite with a narrower work-stopping end and a wider end for mounting and carrying the rod.
In the first embodiment best shown in
The work-stop assembly has either a single angle or double angle stop-collet for clamping selected sizes of work stop-rods. To fasten and unfasten such work stop-rod, the work-stop assembly can be broken down into a rearward shank that slides in the passageway and defines the flat side, and a forward nut that threads onto the front end of the shank. A compression chamber is formed at the junction of the shank and nut to receive the stop-collet and to tighten the stop-collet jaws by increasing threaded engagement of the nut on the shank. The nut and shank have an axial bore allowing depth passage of any work-stop-rod that can he secured within the fastening range of a chosen stop-collet. The size range of the stop-collet determines acceptable rod diameters. Stop-collets of different size ranges might fit the compression chamber and can be substituted in the compression chamber. The axial bore of the nut and shank should be large enough to not limit the use of otherwise fitting stop-collets.
A second embodiment is best shown in
A third embodiment of the stop assembly best shown in
In this third embodiment, the work-stop assembly includes a tube stop in the form of a hollow tube with an array of setscrew reception holes in the sidewall of the tube. The setscrews can secure the tube stop in a rough workpiece blocking position by being inserted through reception holes matching the spacing pattern of the setscrew positions. The tube stop has an open front to receive in the tube a tail or stem of a long workpiece or other as may be desired. A further portion of the work-stop assembly is an adjustable work stop fastened in the rear end of the tube stop to establish a limit of insertion depth by workpiece tails inserted in the front of the tube stop. The work stop may be a threaded rod that is selectively engaged in the rear of the tube stop. A jam nut of the work-stop assembly is threaded onto the threaded rod to lock the threaded engagement with the tube stop.
It is readily understood that all three embodiments employ the work-stop body to be a selective attachment element to the work-holding-collet. The passageway in the work-stop body provides aligned mounting of the work-stop assembly with the central axis of the work-holding-collet, ultimately aligning a stop-rod with the workpiece-receiving mouth of the work-holding-collet. Two position adjusters set the depth of the forward end of the stop-rod. The two position adjusters cooperate, with the first carrying the second, and the second carrying the work stop. One of the two adjusters is conveniently set while the work-stop assembly is removed from the work-holding-collet. This first adjustment is an approximate or rough adjustment to approximately place the work stop at a suitable depth where it will block an incoming workpiece. The second adjuster is axially moved while the work-stop body is installed in the work-holding-collet, which allows exact measurement of the depth of the work stop. The second position adjuster sets the final position of the work stop.
With reference to the drawings, the numbering may employ the same identification number in different drawing figures and in connection with varied embodiments. In instances where the same number is used, the identified component will be the same or closely similar to other components identified by that number. The invention is shown with a forward end positioned generally to the left and as though components are arranged along a longitudinal axis between front and rear ends.
According to
A work-holding-collet 10 is sized, in part, according to the capacity of the machine tool it will work with. For example, a machine tool that employs a work-holding-collet 10 is equipped with a clamping ring 18 that fits around tubular body 14 and is variably engaged over flared end 12 according to a desired degree of clamping to close or open the jaws 16. The jaws close or are more tightly clamped as the clamping ring 18 is applied against a larger diameter of taper 12, and the jaws open or are more loosely clamped as the clamping right is applied against a smaller diameter of taper 12. A work-holding-collet 10 is sized to receive a suitably dimensioned workpiece or tool in its jaws 16. For example, the workpiece or tool must have a rear portion small enough to fit in the workpiece-receiving mouth 17 at the center between the jaws 16 before the jaws are tightened against the workpiece, and the workpiece must be large enough that the jaws will be clamped against it when closed. The work-holding-collet 10 also must be selected to have internal capacity sufficient to handle the workpiece. For example, a portion of the workpiece is inserted into the work-holding-collet 10 behind the jaws 16, and the work-holding-collet 10 must accommodate the inserted portion. Such accommodation involves depth and diameter or cross dimension of the workpiece and may involve initial setting and subsequent resetting of the position of the workpiece in the work-holding-collet 10.
Interior precision threading 20 likewise may be formed on the rear internal surface of the work-holding-collet 10, shown at a rear breakaway at a right hand lower corner of the tube wall 14 in
The work-stop body 22 has a rear end with side flats 26 for engagement by a tool for rotationally twisting the main work-stop body 22, such as to insert or remove the main work-stop body 22 with respect to the work-holding-collet 10. Full or maximum available threaded engagement between the field of threads 24 and field of threads 20 is defined as the degree of engagement when the flange 25 at the rear of threads 24 is grounded against the rear edge of the work-holding-collet 10 to establish a repeatable position of engagement. Flange 25 and the rear edge of the work-holding-collet 10 are precisely perpendicular to a longitudinal central axis of the main work-stop body 22. The main work-stop body 22 has a centerline passageway 28 which may be cylindrical and collinear with the longitudinal central axis of the work-holding-collet 10 and aligned with workpiece-receiving collet mouth 17. The centerline passage 28 establishes at least a portion of the internal capacity of the work-holding-collet 10 for receiving a workpiece.
When a workpiece is fitted into the jaws 16 and workpiece-receiving mouth 17 of the work-holding-collet 10, it is centered on the longitudinal axis of the work-holding-collet 10 as well as on the central longitudinal axis of passage 28. This centering establishes two dimensions of uniform and repeatable positioning. In the first embodiment, the third dimension of uniform and repeatable positioning is established by a distance of penetration of the workpiece into the front end of work-holding-collet 10. With appropriate dimensions, the workpiece can advance along the longitudinal central axis of the work-holding-collet 10 it is blocked or until no further room for penetration is available. However, the end of such room for advancement, by itself, typically will not be the desired limit of penetration for the workpiece. Typically it is necessary to locate a selected limit of penetration by use of an interposed mechanism or object creating a work stop within the work-holding-collet. A practical problem with an internal work stop is difficulty in rapidly and accurately setting the position of the work stop and resetting the axial position of the work stop as necessary.
Third dimensional adjustment of the workpiece is handled by a work-stop assembly 54,
In greater detail, the work-stop body 22 is attached to the rear of the work-holding-collet 10 in threaded engagement that, when fully threaded together, produces a single, fixed, reproducible position between the work-holding-collet 10 and work-stop body 22. The threading is positioned at a radius greater than the radius of passage 28 so that the threaded connection is outside the path of the work-stop assembly 54 and does not limit the available axial position of the work-stop assembly 54.
The work-stop assembly 54 is a compound axial slider operating in passageway 28. Axial adjustment is made by linear movement of the slider within passage 28. The slider is formed in part by a shank 30, which is a longitudinal tube that is sized to accurately fit passage 28. The tube is generally cylindrical and of diameter to fit passage 28, but with a longitudinally extending external flat edge 31 that engages with the setscrews 32. Rotationally positioning the flat edge 31 to face setscrew counterbores 33, enables shank 30 to be secured in a selected axial position in passageway 28. Setscrews 33 establish a lock when secured against flat edge 31. A preferred location for the counterbores 33 is near the rear end of the passage 28. The shank 30 can be rotated on the axis of passage 28 to orient the flat edge 31 to face the counterbores 33. The setscrews 32 are nonmarring, flat point, socket setscrews. The use of this type of setscrew preserves the flatness of edge 31 against marring, thereby ensuring that the shank continues to be precisely lockable in any selected axial position with respect to the work-stop body 22.
The stop-collet 34 is smaller than work-holding-collet 10, is a further component of the work-stop assembly, and readily fits inside the tubular body 14 for allowed longitudinal movement. The stop-collet 34 has a front compressible head 35 with a mouth operated by jaws. Stop-collet 34 also has a trailing tail 36 with a through passage that fits in line with core 43. The front end of the shank 30 forms a tail cavity 37 that receives the tail 36 of the stop-collet 34 and leaves the head 35 with its rear edge grounded against the rear end of a rear edge 49 of the head cavity 39.
Stop nut 38 of the work-stop assembly fits by threaded engagement over the front end of the shank 30, and forms a front portion of interior head cavity 39. The front of cavity 39 fits over the front of head 35 of the stop-collet 34. Increasing engagement of the threaded connection between stop nut 38 and shank 30 compresses the collet head 35, closing the jaws and mouth of stop-collet 34 on an inserted work stop-rod 40, if present. Contacting surfaces of the stop-collet head 35 and head cavity 39 are angularly configured with flares and tapers to further help compress the jaws of the collet head 35 when the nut 38 is tightened on the shank 30. A work stop-rod 40 can be secured at a selected forward extension from the stop-collet 34 by tightening the stop nut on the shank, thereby compressing head 35. Thereafter, the shank 30 is inserted into passage 28, and the work-stop body 22 is fastened by its predetermined engagement with work-holding-collet 10. Then, it becomes possible to insert a workpiece into work-holding-collet 10 and determine a desired length of insertion into work-holding-collet 10. When the insertion is so determined, the shank 30 is pushed forward placing the work stop-rod against the workpiece and secured in position by tightening setscrews 32 on the shank.
A benefit of the described dimensional adjustment through axial movement of the work-stop assembly is that the work stop-rod 40 can be selected with great variation. A low-cost, conventional gage pin is suitable. The length of the gage pin need not be custom machined for each job, because a rough, preliminary setting in stop-collet 34 is sufficient to eliminate this common need. The further length adjustment by setting the shank 30 in the passageway 28 of the work-stop body 22 provides additional precision of depth setting without modification of the gage pin.
Additional features support the flexible choice of a work stop-rod 40. The shank 30 has a hollow longitudinal center bore 42 and an externally threaded front end 44. As shown in
As best shown in
Various types of stop-collets 34 are suitable for use, including a single angle collet or a double angle collet. The illustrated collet 34 is a double angle collet, also known as a DA collet, and is a preferred choice. Such a double angle collet is split to form jaws at both front and rear ends. At the forward end, a DA stop-collet has an enlarged head with clamping jaw, as shown at the front of collet 34 in
A work stop-rod 40 preferably is a uniform diameter rod. One suitable type of rod is a conventional gage pin. This choice is desirable because a gage pin is a convenient and inexpensive option. Gage pins are handy because they are available in very minute increments—usually 0.001 inch steps—and affordable. In some applications where it may be preferred to not use a gage pin, other types of work stop-rod blanks also are suitable. As an example and not a limitation, suitable rod blanks may be drill rod, dowel pins, precision shafting, cylindrical rod, gage pins or the like. A chosen work stop-rod is axially aligned to enter the capacity bore of the work-holding-collet 10 and to enter the stop-holding hollow center 52 of an appropriately sized stop-collet 34. As shown in
In the first embodiment, the sliding assembly of
An internal stop-collet 34 can handle gage pins or other work stop-rods 40 over a range of diameters. For example, a ⅛ inch DA collet might accommodate gage pins over a size range of 0.5 mm. Different capacity stop-collets 34 can be accommodated in the head cavity 39 and tail cavity 37, further expanding the range of sizes for work stop-rods 40 that can be handled within the same shank 30.
An improvement of the invention is that uniform work stop-rods 40 such as gage pins or others are readily available in a variety of standard sizes, and a selection of such standard sized work stop-rods are directly useable as collet stops with a single internal stop-collet 34. The component parts of an assembly 54 offer changeability of sizes to fit a suitable gage pin or other work stop-rod for the needs of the work-holding-collet 10 to handle a particular workpiece. Changeover entails exchanging work stop-rod 40 of the desired size into the collet 34, tightening the stop nut 38, sliding the shank 30 to a final position in passage 28 for the job, and tightening the two setscrews 32 into counterbores 33 and against the shank. By this system, notable time consuming and often costly steps are eliminated. In particular, where in the prior art the work stop-rod 40 may need custom machining at each step in a fabrication, the present system is adaptable to use a set of different sized, standard gage pins or other mentioned examples as work stop-rods. Where in prior art the work stop-rod often used multiple diameter segments due to the need to clamp the work stop-rod at a fat middle section, the present system uses single diameter, standard work stop-rods, which can be received in a small, internal stop-collet 34 that accommodates a variety of rod diameters. Where in the prior art a work stop-rod carrier was screwed into the work-holding-collet 10 and adjusted by manipulation of the entire work-holding-collet, the present system offers simple rough adjustment of the work-stop assembly 54 while it is removed from the work-holding-collet 10, with final adjustment by simple sliding action of the shank 30 in bore 28 and clamping the shank with setscrews. Thus, changeovers are done rapidly and inexpensively, without requiring further machining of the work stop-rod 40.
The work-holding-collets 10, 64 provide improved simplicity in making both rough and final position settings of a work stop-rod. The rear end of the workpiece likely is located inside the work-holding-collet 10, 64. The stop-collet 34, 68 likewise is internal to the work-holding-collet 10, 64. In each embodiment, a preliminary or rough setting of a work stop is made outside the work-holding-collet. Fine or final adjustment of the work stop with respect to the work-holding-collet 10, 64 is made from outside the work-holding-collet.
In the embodiment of
The work-holding-collet 64 of
An axially elongated tube stop 78, also referred to as a bucket stop, fits closely within passage 28, where it is secured in at selected depth within work-stop body 22 by setscrews 32. Tube stop 78 has an elongated hollow core that is axially aligned with the centerline of the work-holding-collet 64 and work—stop body 22, which enables an elongated workpiece 98 to be inserted through workpiece-receiving mouth 67, through passage 28, and into the core 79 of tube stop 78 by a selected distance. Tube stop 78 is configured with an array of transverse receptor holes 80 arranged at a longitudinal periodic spacing along the length of the tube stop 78. The illustrated two setscrews 32 can be placed into any pair of successive reception holes 80 to establish a positive stop for an inserted workpiece 98. The periodic distance spacing of reception holes 80 is coordinated with the axial separation of the counterbores 33 so that a longitudinally successive pair of reception holes 80 is secured to the pair of setscrews 32. The collet jaws 66 continue to function as the work holder during machining operations.
The adjustable tube stop body 78 is a tubular or cylindrical metal adaptor for elongated workpieces and is held in place with non-marring setscrews 32. The tube stop body 78 has the series of reception holes 80 that will not allow the tube stop body to move either axially or rotationally when the non-marring setscrews 32 are tightened into selected reception holes 80 of the tube stop body. The reception holes 80 in the tube stop body 78 are arranged in a plurality of “R” axial rows, such as where R=4. Such four axial rows would be positioned on the tube stop body at rotationally separated positions. Starting at a twelve o′clock position 82 in
The rear end 92 of the tube stop 78 is internally threaded. As evident, adjustment using the reception holes 80 is rough. A threaded work stop-rod 90 is engaged in threaded rear end 92 of tube 78 to make finer adjustment, which is achieved by rotating the work stop-rod 90. A threaded lock nut 94 secures the position of the work stop-rod when turned against the rear end of the tube 78. The work stop-rod 90 and lock nut 94 extend behind the rear of the work-holding-collet 64, such that they are external and exposed to enable fine adjustment from outside the work-holding-collet 64. Remaining adjustment such as screwing the work-stop body 22 into the rear end threads 20 of work-holding-collet 64 or setting the position of the tube stop 78 into the work-stop body 22 are fixed or repeatable even before the work-holding-collet 64 is mounted on a machine spindle, so that high precision can be achieved by external adjustment after the work-holding-collet 64 is fully mounted and carrying the workpiece 98.
The embodiment of
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be regarded as falling within the scope of the invention as defined by the claims that follow.
| Number | Date | Country | |
|---|---|---|---|
| 62914482 | Oct 2019 | US |
