CA2143122A1 - Clamping device for tool holders - Google Patents
Clamping device for tool holdersInfo
- Publication number
- CA2143122A1 CA2143122A1 CA002143122A CA2143122A CA2143122A1 CA 2143122 A1 CA2143122 A1 CA 2143122A1 CA 002143122 A CA002143122 A CA 002143122A CA 2143122 A CA2143122 A CA 2143122A CA 2143122 A1 CA2143122 A1 CA 2143122A1
- Authority
- CA
- Canada
- Prior art keywords
- clamping
- tool holder
- clamping device
- journal
- ejecting
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B29/00—Holders for non-rotary cutting tools; Boring bars or boring heads; Accessories for tool holders
- B23B29/04—Tool holders for a single cutting tool
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
- B23B31/02—Chucks
- B23B31/10—Chucks characterised by the retaining or gripping devices or their immediate operating means
- B23B31/107—Retention by laterally-acting detents, e.g. pins, screws, wedges; Retention by loose elements, e.g. balls
- B23B31/1075—Retention by screws
- B23B31/1077—Retention by screws acting on a floating pin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2250/00—Compensating adverse effects during turning, boring or drilling
- B23B2250/12—Cooling and lubrication
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Gripping On Spindles (AREA)
- Auxiliary Devices For Machine Tools (AREA)
Abstract
A clamping device for connecting basic holders or machine spindles with tools ortool holders for machining comprises two partable clamping elements (22,24) which, with radially outwardly projecting clamping jaws (32,40) engage behind clamping shoulders (20,22) inside the machine spindle and the tool holder (12).
There are 2 clamping elements (22,24), which are connected over their central portion to a clamping block with the aid of a parting element (26). In the closed state, the outer diameter of the clamping block is smaller than the smallest inner diameter of both the machine spindle and the tool holder.
There are 2 clamping elements (22,24), which are connected over their central portion to a clamping block with the aid of a parting element (26). In the closed state, the outer diameter of the clamping block is smaller than the smallest inner diameter of both the machine spindle and the tool holder.
Description
2~ 13122 CLAMPING DEVICE FOR TOOL ~IOLDERS
The invention relates to a clarnping device for connecting basic holders or machine spindles with tool holders or tools for m~chining, with partable staple-shaped 5 clamping elements which, with radially outwardly projecting clamping jaws, engage behind clamping shoulders inside the machine spindle and the tool holder.
A clamping device of this type is disclosed in DE-C 39 04 259. The prior art device has three clamping elements distributed at 120 over the periphery, which, with the 0 jaws located at one end, are permanently engaged with an inwardly projecting shoulder of a basic holder. Positioned in the jaws on the tool holder side are radial adjusting screws which can be operated through a corresponding radial bore from outside the tool holder. The adjusting screws have a tapered tip which, when theadjusting screws are operated, comes into contact with the tapered tips of the two other adjusting screws. The tips pressed against each other when the adjusting screws are operated are intended to pivot the staple-shaped clamping elements outwardly around the end Iying on the basic holder side and to engage the jaws on the tool holder side with the latter's inwardly projecting shoulder.
20 There are various reasons for reservations about the suitability of this solution in practice. The tapered tips are surely exposed to a high degree of abrasion. There is a further disadvantage in that the tool holder has to be provided with a bore in the vicinity of its taper, so that it is not possible to use just any tool holders. As a glance at the drawing shows, a very large number of parts is required and hence 25 production, assembly and maintenance are costly. There is only a restricted axial passage for coolant pipes.
The tool holder, whose mainly flatly tapered shank is self-lockingly clamped in the machine spindle or in the basic holder, cannot be ejected when the tool holder is 30 loosened.
~3i~
-Particularly where the tool holders or tools with hollow shanks specified under DIN 69893 are concerned, it is also necessary, in addition to prior art mech~ni~m.c for automatic clamping with machine spindles, to create clamping devices which can also be operated m~ml~lly. In doing so, various requirements have to be met to ensure reliable operation and to limit the cost of construction:
- The clamping force should be spread as uniformly as possible over several clamping points distributed over the periphery of the inwardly projecting shoulder or clarnping surface of the hollow shank of the tool holder. This is lo the only way to ensure achieving the effect which can be attained via the hollow shank of an inwards to outwards elastic distortion in the relatively thin-walled taper to achieve a high degree of contact pressure on the inner taper of the machine spindle or the basic holder. Furtherrnore, a uniform axial pulling force results in a rigid clamp between the front face of the m~chine spindle or the basic holder and the flange of the tool holder. Since it is practically impossible to achieve the ideal case where the entire surface of the clamping device rests against the entire encircling shoulder, a uniform distribution overseveral defined clamping surfaces should at least be achieved.
20 - The res ]lt~n~ force lines should be as short as possible, and the lateral forces exerted on the machine spindle or the basic holder on the one hand, and on the tool holder on the other hand, should be as low as possible.
- It ought to be possible to convey coolants at the centre of the machine spindle through the clamping system to the tool holder and tool.
- In view of the flatly tapered hollow shank of the tool holder and the self-locking which occurs on clamping, it ought to be possible to apply a high ejection force.
As stated, these requirements are only partially met by the aforementioned prior art clamping device, and only at a high construction cost.
~ 2143122 Even costlier is the clamping device described in EP-A-0 451 360. This also provides for staple-shaped clamping elements which engage behind clamping shoulders or clamping surfaces inside the basic holder or the machine spindle on-- the one hand, and the tool holder on the other hand, with the aid of jaws. Here, too, the jaws on the basic holder side are captive whilst on the tool holder side, they are engaged by pivoting the clamping elements. To effect this pivoting, there is a tapered quill which has to be displaced in the axial direction. This displacement is effected with the aid of a clamping nut screwed onto the quill, which has to be rotated from the outside via a worm gear. This must be even costlier than the o aforementioned embodiment according to DE-C 39 04 259.
The invention is based on the task of creating a clamping device of this generictype, which is simple, robust and does not require much m~inten~nce, thus allowing economic use, and which, furthermore, does not entail eh~n~in~ or modifying the standard toolholders as defined by DIN 69893.
According to the invention, in a device of the aforementioned type this task is solved by connecting 2 clamping elements with the aid of a parting element to a clamping block whose outer diameter in the closed position is smaller than the 20 smallest inner diameter of both the machine spindle and the tool holder, and in that the clamping elements each have two clamping surfaces on both sides which are disposed such that the four clamping surfaces of the two clamping elements are each distributed over the periphery of the clamping shoulders at angular distances of approx. 90.
On both sides, the clamping elements each have two clamping surfaces which are disposed such that the four clamping surfaces of the two clamping elements are each distributed over the periphery at an angular distance of approx. 90. This results in a very uniform and syrnmetrical distribution of the clamping force on the 30 clamping shoulders of the basic holder and the tool holder and, ~imlllt~neously~ a symmetrical contact force distributed over the periphery between the inner taperand the outer taper and between the relevant front faces. This is particularly important because this absorbs the radial stress on the clamping point caused byencircling bending forces.
21~31~2 The unit desi~n~ted in this context as the clamping block, consisting of two clamping elements and a parting element, can be mounted in its assembled state as a unit into its intended position. Equally, it can easily be completely removed for checking and m~inten~nce purposes. It is not necessary to assemble a large number 5 of relatively complicated parts with difficulty inside the basic holder or the machine spindle. The flow of power takes place via the shortest path and almost without any occurrence of lateral forces between the basic holder and the tool holder.
Modifications to the standard tool holder are not necessary.
o To simplify the following embodiments, reference will for the most part only be made to the connection between a basic holder and a tool holder, although a machine spindle can be provided in place of the basic holder, and a tool in place of the tool holder.
15 In one pr~relled embodiment, the parting element is a di~ele,lLial screw which lies inside the two sl~mping elements in oppositely coiled tapped holes. The advantage of this solution is that the clamping elements are inevitably guided when they are parted and drawn together. However, the parting element could also be a parting screw which is screwed into one of the clamping elements and rests against the 20 other, or even a shank taper which is drawn between the clamping elements.
The parting element can be reached with a suitable tool through a radial bore in the basic holder. The parting element is preferably connected via a detachable, non-rotating plug connection with a clamping journal which allows a plug-in tool to be 2s connected and which lies in the radial bore of the basic holder. Furthermore, a second, oppositely positioned bore is preferably provided in the basic holder, in which lies an ejecting journal from which proceeds a centering pin which engageswith play in a front face blind bore in the parting element. The clamping journal and the ejecting journal lie in front face recesses on opposite sides of the standard 30 tool holder. Simultaneously, they serve as drivers for the tool holder.
215~122 The parting element can also take the form of an eccentric cam. This results in the significant advantage that the clamping elements can be fully parted by a rotation of maximum 90, whilst with a di~e. en~ial screw or other parting screw several full rotations may be necess~ry under certain circllm~t~nces. The use of an eccentric5 cam as the parting element is therefore particularly advantageous in those cases where the tool has to be clamped in position in a restricted space or in positions where access is difficult.
However, whilst a dirrerenLial screw can both part and draw together the clamping o elements, if an eccentric carn is used the clamping elements can only be parted. The clamping elements can, for example, be retracted with the aid of jaws which are non-rotabably connected with the eccentric cam, which engage in pockets on the inside of the clamping elements and which pull the clamping elements inwards.
Additionally, or alternatively, the use of a return spring could be considered.
The ejecting journal preferably has a non-circular or cam-shaped section and is disposed in relation to the base of the associated recess in the tool holder in such a way that the tool holder can be ejected from the basic holder with the aid of the radial-outer portion of the flattened part by rotating the ejecting journal.
The clamping journal and the ejecting journal also have the additional function of floatingly guiding the clamping block in the unclamped position in the vicinity of the interface of the basic holder and the tool holder.
25 According to another prerelled embodiment, in one ofthe clamping elements there is at least one ejecting pin which runs through the second clamping element to the opposite side, which, when the clamping block is screwed together, comes into contact via one front face sloping surface with an opposite surface of the tool holder and displaces the tool holder in the direction of ejection Said sloping 30 surface can be a conical tip of the ejecting pin, and the ejecting pin can engage via the thread in the first clamping element and in this way be longit~l-lin~lly adjustable.
21~312~
As the opposite surface in this context, the base of one of the front face recesses in the tool holder could be considered.
According to another p-efe-led embodiment, the front faces of the clamping elements closest to the tool holder can be provided with sloping surfaces which, on being drawn together, run up against the sloping surfaces of a connecting element, possibly a coolant adapter, which displaces the tool holder in the direction of ejection.
If an eccentric cam is used as the parting element, one of the cam surfaces of the eccentric cam can run up against a sloping surface which is rigidly connected with the machine spindle when the clamping jaws are loosened by rotating the eccentric cam, so that the tool holder is ejected in this way.
S The interacting surfaces of at least one clamping shoulder and one pair of clamping jaws are preferably at least partially sloped so that when the clamping elements are radially parted, an axial pull is .cimlllt~neously exerted on the tool holder.
On the sides facing each other, the clamping elements can have at least one recess which allows the passage of at least one coolant pipe through the interface between the basic holder and the tool holder.
Entering in their radial direction into the radial bores of the basic holder which accommodate the clamping journal and the eiecting iournal, there are stud bolts which can be screwed into encircling grooves in the clamping journal and the ejecting journal. In this way, the clamping journal and the ejecting journal can be fixed in the axial direction, without being hindered in their rotation.
With respect to the state of the art, reference is also made to EP-B 0 172 850 and WO 88/05358, which, in a comparable context, disclose the use of di~ele,lLial screws for parting clamping elements. However, said publications relate to solutions which overall are not comparable with the problem posed in this instance, 21~3122 and which overall do not meet the stated requirements.
Other features and advantages of the invention result from the sub-claims.
5 Preferred examples of embo~ nentc of the invention will be described in more detail below with reference to the enclosed drawings, in which Fig. 1 shows a partial cross-section of a basic holder with tool holder and clamping device in the clamped state;
Fig. 2 is a partial cross-section from the left in Fig. 1 and shows the clamping device in the clamped position;
Fig. 3 is equivalent to Fig. 2, but shows the closed position of the clamping block;
Fig. 4 is a part section along the line 4-4 in Fig. 1;
Fig. 5 is equivalent to Fig. 1, but shows a different embodiment of the ejecting device;
Fig. 6 is equivalent to Fig. 2, but shows a front elevation of the embodiment of Fig. 5;
Fig. 7 is a part section along the line 7-7 in Fig. 5;
Fig. 8 shows another embodiment of an ejecting device;
Figs. 9a, b and c depict various cross-sections of the clamping shoulders;
Fig. 10 shows another embodiment of the invention with an 2 1 ~ 2 eccentric cam as the parting element;
Fig. 11 is a section along the line 11 - 11 in Fig. 10;
Fig. 12 is an enlarged top plan view of an eccentric cam;
Fig. 13 shows the clamping device of Fig. 10 in the parted position;
o Fig. 14 is a section along the line 14-14 in Fig. 13;
Fig. 15 is a top plan view of the eccentric cam in the parted position.
Figs. 1 to 3 will be considered first. Fig. 1 shows to the left a basic holder 10, in place of which, as mentioned, there could be a machine spindle, and to the right a tool holder 12. The basic holder 10 has an inner taper 14, which corresponds with an outer taper 16 in the tool holder 12. The outer taper of the tool holder borders on a hollow shank, inside which a clamping shoulder 18, which is inclined at less than 30G, projects according to the aforementioned DIN 69893 standard.
Inside the basic holder 10 there is also a hollow space not design~ted in further detail, in which an inwardly projecting clamping shoulder 20 is located. In the example shown, the clamping shoulder 20 is sloped at less than 30 in the opposite direction to the clamping shoulder 18 of the tool holder.
Inside the hollow space formed by the basic holder 10 and the tool holder 12 there are, at the top and the bottom in Figs. 1 to 3, two clamping elements 22, 24, which are connected via a di~le,lLial screw 26 to a partable clamping block. The thread of the di~elt;ll~ial screw 26 engages via oppositely coiled thread portions 28,30 with corresponding tapped holes (not deei~n~ted) in the clamping elements 22, 24.
Rotating the difrelellLial screw 26 therefore allows the clamping elements 22,24 to be parted or brought together. The clamping elements 22,24 are prevented from 2~3122 g - rotating and mi~ligning themselves by the fact that they abut to the left against an encircling shoulder (not design~ted) inside the basic holder, or are located in the - immediate vicinity thereo In the front elevation of Figs. 2 and 3, the clamping elements 22,24 have an ess~nti~lly rect~n~ r profile and with their two outer corners form four jaws 32,34,36,38, which are shown more precisely in Fig. 1. As Fig. 1 shows, the clamping elements 22,24 are staple-shaped, so that they not only have the jaws 32,34,36,38 to be seen in Fig. 2, but also four corresponding jaws at the axially 0 opposed end, of which jaws 40 and 42 can be seen in Fig. 1. The jaws 32 to 42 form four clamping surfaces on each axial side, which, corresponding with the inclination of the clamping shoulders 18,20, are also inclined at less than 30. It can be seen that by radially parting the clamping elements 22,24, the tool holder 12 is axially drawn into the basic holder 10 and is subsequently also radially parted.
To rotate the di~rellLial screw 26 and thus to part or draw together the clamping elements 22,24, a clamping journal 44 is provided, which lies in a radial bore 46 in the basic holder 10. The clamping journal 44 also runs through a front face recess in the left edge of the tool holder 12, which is prescribed by the aforementioned standard. In this way the clamping journal siml.lt~neously exercises a driver function for the tool holder 12 when the basic holder 10 is rotated. At the radial-inner end of the overall cylindrical clamping journal 44, a hexagon spigot 50 projects inwardly into a corresponding recess (not dçsign~ted) in the bottom front face of the di~erell~ial screw 26. A di~e~ , non-circular cross-section can naturally also be used instead of the hexagonal cross-section. On its radial-outer front face the clamping journal also has a hexagon socket 52 which allows an appropriate tool for rotating the clamping journal 44 to be connected. As shown in Fig. 2, the section of the clamping journal 44 which lies in the basic holder 10 is provided with an encircling groove 54, in which engages a stud bolt 56 which is screwed into the wall of the basic holder 10 perpendicular to the axis of the clamping journal 44. Interacting with the groove 54, the stud bolt 56 fixes the clamping journal 44 in the axial direction, but allows it to rotate.
21~3122 ~o On the side diametrically opposed to the clamping journal 44 there is another radial bore 58 in the wall of the basic holder, in which lies an eiecting journal 60 which is the equivalent of the clamping journal 44. Projecting radially inwards from the inner end of the ejecting journal 60 there is a centering pin 62, which engages with 5 play in a front face bore 64 in the dirreren~ial screw 26 at the upper end thereof in Fig. 1. With the aid of the hexagon spigot 50 of the clamping journal 44 and thecentering pin 62 of the ejecting journal 60, the clamping block consisting of the two clamping elements 22,24 and the di~lenLial screw 26 is held floatingly in the unclamped state (Fig. 3) inside the hollow space ofthe basic holder 10 and the tool o holder 12. As Fig. 2 shows, the ejecting journal 60 is also fixed in the axialdirection by a stud bolt 66. Furthermore, the eiecting journal 60 also lies in a front face recess 68 in the tool holder 12 and thus also serves as a driver for the latter when the basic holder is rotated.
5 A further function of the ejecting journal 60 lies in that its section 70 which lies in said recess 68, shown in Fig. 4 in cross-section, is non-circular and has a flattened side 72 which lies opposite the base of the recess 68. When the ejecting journal 60 is rotated, pressure towards the right in Fig. 1, i.e. in the direction of ejection, is thus exerted on the tool holder 12. For the purpose of effecting this rotation, the 20 ejecting journal 60 is also fitted on its outer front face with a hexagon socket 74.
Finally, Figs. 2 and 3 show that on the facing sides on both sides of the diLre~e~lLial screw 26, the two clamping elements 22,24 have corresponding, semi-circular recesses 76,78,80,82 which complement each other to form a circular hollow space25 when the clamping elements 22,24 are drawn together. These hollow spaces with a circular cross-section serve to accommodate coolant pipes 84,86 which connect a coolant adapter 88 and a coolant distributor 90 which are part of a coolant system, not shown separately, for cooling the tools.
Figs. 5 to 7 are ess~n~i~lly equivalent to Figs. 1, 2 and 4 and will therefore only be explained with regard to the differences.
21431~
These differences relate to the ejecting system for ejecting the tool holder 12 out of - the basic holder 10.
According to Figs. S and 6, screwed adjustably into the upper clamping element 22 - 5 there are two ejecting pins 92,94 which run through the lower clamping element 24 as shown in Figs. 5 and 6 in corresponding bores (not deci~n~ted~. The threaded engagement with the upper clamping elements 22 permits longi~ltlin~l adjustm~nt The bottom ends of the ejecting pins 92,94 are truncatedly sloped, as can be seen in Fig. 6.
It is obvious that when the clamping elements 22,24 are screwed together with the aid of the differential screw 26, the clamping pins 92,94 protrude downwards outof the bottom clamping element 24. In doing so, as Fig. 7 shows, they come into contact, directly bordering on the periphery of the lower clamping journal 44 in the two corners ofthe front face recess 48 ofthe tool holder 12, with the edges ofthe recess. As a result of the sloping surfaces of the trllnc~ted ends of the ejecting pins 92,94, an axial pressure is exerted on the tool holder, which leads to it being ejected. When this ejection procedure takes place, the entire clamping block cannot yield upwardly as in Figs. 1 and 2 since the top portion of the upper clamping element rests against the clamping shoulders.
Fig. 8 is a partial representation relating to Fig. 1, and is limited to showing the two closed clamping elements 22,24 and the coolant distributor 90. The coolant distributor 90 has, in the longitu~in~l central axis of the basic holder and the tool holder, on the side closest to the clamping elements, a tnlnc~ted connecting element 91 which is associated with corresponding recesses (not decign~ted) on the opposite surfaces of the clamping elements 22,24, which, when the clamping elements are drawn together, complement themselves to form a truncated recess.
When the clamping elements 22,24 are drawn together, the corresponding sloping surfaces cause pressure to be exerted on the coolant distributor 90, which as shown in Fig. 1, borders closely against the inner surface of the tool holder, in the direction in which the tool holder is ejected.
Figs. 9a,b and c show vanous cross-sections of the clamping shoulder 20 of the basic holder. The representation shown in Fig. 9c corresponds with that in Figs. 1 21~122 and 4. In Fig. 1, a completely radial clamping shoulder is shown in connection with a correspondingly shaped clamping surface on the clamping elements. Fig. 9b is acombination of the two possibilities and shows a partially sloped, partially radially - shaped clamping shoulder.
s When assembling a tool holder the two clamping surfaces 22,24 are first screwed shut on the block with the aid of the di~~ ial screw. In this state they can be introduced inside the basic holder or the machine spindle. With the aid of the clamping journal 44 and the ejecting journal 60, they are then floatingly f~xed in 0 position. The clamping device can now be operated. In this direction they allow a tool holder to be inserted into the basic holder. The tool holder merely has to be rotated until the clamping journal 44 and the ejecting journal 60 engage in the corresponding front face recesses 48 and 68 of the tool holder. If the clamping journal 44 is now rotated, the two clamping elements move apart in step in the 1S radial direction until the jaws come into contact with the clamping shoulders 18,20 of the tool holder and the basic holder or the machine spindle. By contimling the clamping operation the tool holder is drawn axially inwards into the basic holder.
When this happens clamping pressure builds up on the front face of the basic holder and the tool holder, and sim~llt~neously~ increasing radial pressure which 20 builds up over the clamping surfaces and clamping shoulders, causes the relatively thin-walled taper of the tool holder to widen and press against the inner taper of the basic holder. Once a given torque is att~ined the clamping process ends and a tight connection is formed between the basic holder or machine spindle and the tool holder.
2s The reverse procedure results in loosening. However, since the inner taper of the basic holder and the outer taper of the tool holder are relatively flat, self-locking occurs so that a separation does not automatically take place. Various alternative ejecting devices for the purpose of ejecting have therefore been described above, 30 and the manner in which they operate can be inferred from the pre~ious description.
Figs. 10 to 15 relate to another embodiment of the clamping device of the invention, which differs from the embodiment of Figs. 1 to 6 above all in that the ~1~31~2 -parting element is not a differential screw, but an eccentric cam. The eccentric cam - can be rotated in the manner already described, yet only requires an angle of rotation of maximum 90. Otherwise, the main difference in the construction withrespect to the embodiment described above lies onIy in the fact that the axis of the eccentric cam runs between the two clamping elements, whilst with the differential screw, it runs vertically through the two clamping elements.
Because of the numerous conformities with the first embodiment the individual parts in Figs. 10 to 15 bear reference numerals which correspond with those of the 0 first embodiment but have merely been increased by 100. A further description is therefore largely unnecessary. Parts not present in the first embodiment and which relate to the eccentric cam are desi,en~ted by reference numerals starting from 200.
Figs. 10 and 11 show clamping elements 122,124 in the closed position. An eccentric cam 200 which is shown in Fig. 12 on its own and slightly enlarged, but in the position of Fig. 10, has an elongated shape with two parallel edges 202,204 and two cam surfaces 206,208. The gap between the straight edges 202,204 is much smaller than the gap between the cam surfaces 206,208. As shown in Figs.
10 to 12, the eccentric cam 202 lies flatly, ie. with the top and bottom edges 202,204 between the clamping elements 122,124 so that the latter can be displaced inwards, thereby releasing the tool holder. The clamping elements will not of course move inwards, ie. towards the axis of rotation of the arrangement, of their own accord since they can be held self-lockingly against the clamping shoulders 118,120 and the bottom clamping element at least will remain in the bottom 2s position due to gravity. Therefore, to draw them together, there may be springs, rubber bands or suchlike, whose pulling force may not under certain circumct~nces be sufficient to overcome the self-locking forces on the clamping shoulders.
Therefore, according to the invention, jaw discs 210,212 are non-rotatably secured to the axis of rotation of the eccentric carn on both the front faces thereof. The jaw discs have two oppositely positioned radially projecting jaws 214,216 which, when the eccentric cam is rotated in the unclamping direction, ie. approximately anti-clockwise in Fig. 10, engage in pockets 218,220 on the `~ 214~1~2 radial-inner side of the clamping elements 122,124. A portion of the pockets - 218,220 is undercut and in this manner they forrn shoulders 222,224 against which the jaws 214,216 abut on anti-clockwise rotation in Fig. 10, so that the clamping - elements are driven inwards.
From Fig. 12 it can be seen that the two carn surfaces 206,208 slope very flatly so that when the cam surfaces interact with the insides of the clamping elem~nt~ 122, 124, self-locking occurs.
o Figs. 13 and 15 are equivalent to Figs. 10 to 12, but show the clamping device in the clamped position. In this case the eccentric cam 200 is positioned vertically in Figs. 13 and 15. The jaws 214,216 point upwards and downwards. The clamping elements 122,124 engage in the manner already described behind the clamping shoulders 118,120 of the basic holder and the tool holder.
To eject the tool holder 112 where an eccentric cam 200 is used as the parting element, there can be a sloping surface 226 (Fig. lS) which is rigidly connectedwith the tool holder 112, which the carn surface runs up against when the eccentric cam is loosened, so that the tool holder is ejected. As shown in Fig. 15, the sloping surface is contrived at the end of a pin 228 which is screwed into the coolant distributor 190.
The invention relates to a clarnping device for connecting basic holders or machine spindles with tool holders or tools for m~chining, with partable staple-shaped 5 clamping elements which, with radially outwardly projecting clamping jaws, engage behind clamping shoulders inside the machine spindle and the tool holder.
A clamping device of this type is disclosed in DE-C 39 04 259. The prior art device has three clamping elements distributed at 120 over the periphery, which, with the 0 jaws located at one end, are permanently engaged with an inwardly projecting shoulder of a basic holder. Positioned in the jaws on the tool holder side are radial adjusting screws which can be operated through a corresponding radial bore from outside the tool holder. The adjusting screws have a tapered tip which, when theadjusting screws are operated, comes into contact with the tapered tips of the two other adjusting screws. The tips pressed against each other when the adjusting screws are operated are intended to pivot the staple-shaped clamping elements outwardly around the end Iying on the basic holder side and to engage the jaws on the tool holder side with the latter's inwardly projecting shoulder.
20 There are various reasons for reservations about the suitability of this solution in practice. The tapered tips are surely exposed to a high degree of abrasion. There is a further disadvantage in that the tool holder has to be provided with a bore in the vicinity of its taper, so that it is not possible to use just any tool holders. As a glance at the drawing shows, a very large number of parts is required and hence 25 production, assembly and maintenance are costly. There is only a restricted axial passage for coolant pipes.
The tool holder, whose mainly flatly tapered shank is self-lockingly clamped in the machine spindle or in the basic holder, cannot be ejected when the tool holder is 30 loosened.
~3i~
-Particularly where the tool holders or tools with hollow shanks specified under DIN 69893 are concerned, it is also necessary, in addition to prior art mech~ni~m.c for automatic clamping with machine spindles, to create clamping devices which can also be operated m~ml~lly. In doing so, various requirements have to be met to ensure reliable operation and to limit the cost of construction:
- The clamping force should be spread as uniformly as possible over several clamping points distributed over the periphery of the inwardly projecting shoulder or clarnping surface of the hollow shank of the tool holder. This is lo the only way to ensure achieving the effect which can be attained via the hollow shank of an inwards to outwards elastic distortion in the relatively thin-walled taper to achieve a high degree of contact pressure on the inner taper of the machine spindle or the basic holder. Furtherrnore, a uniform axial pulling force results in a rigid clamp between the front face of the m~chine spindle or the basic holder and the flange of the tool holder. Since it is practically impossible to achieve the ideal case where the entire surface of the clamping device rests against the entire encircling shoulder, a uniform distribution overseveral defined clamping surfaces should at least be achieved.
20 - The res ]lt~n~ force lines should be as short as possible, and the lateral forces exerted on the machine spindle or the basic holder on the one hand, and on the tool holder on the other hand, should be as low as possible.
- It ought to be possible to convey coolants at the centre of the machine spindle through the clamping system to the tool holder and tool.
- In view of the flatly tapered hollow shank of the tool holder and the self-locking which occurs on clamping, it ought to be possible to apply a high ejection force.
As stated, these requirements are only partially met by the aforementioned prior art clamping device, and only at a high construction cost.
~ 2143122 Even costlier is the clamping device described in EP-A-0 451 360. This also provides for staple-shaped clamping elements which engage behind clamping shoulders or clamping surfaces inside the basic holder or the machine spindle on-- the one hand, and the tool holder on the other hand, with the aid of jaws. Here, too, the jaws on the basic holder side are captive whilst on the tool holder side, they are engaged by pivoting the clamping elements. To effect this pivoting, there is a tapered quill which has to be displaced in the axial direction. This displacement is effected with the aid of a clamping nut screwed onto the quill, which has to be rotated from the outside via a worm gear. This must be even costlier than the o aforementioned embodiment according to DE-C 39 04 259.
The invention is based on the task of creating a clamping device of this generictype, which is simple, robust and does not require much m~inten~nce, thus allowing economic use, and which, furthermore, does not entail eh~n~in~ or modifying the standard toolholders as defined by DIN 69893.
According to the invention, in a device of the aforementioned type this task is solved by connecting 2 clamping elements with the aid of a parting element to a clamping block whose outer diameter in the closed position is smaller than the 20 smallest inner diameter of both the machine spindle and the tool holder, and in that the clamping elements each have two clamping surfaces on both sides which are disposed such that the four clamping surfaces of the two clamping elements are each distributed over the periphery of the clamping shoulders at angular distances of approx. 90.
On both sides, the clamping elements each have two clamping surfaces which are disposed such that the four clamping surfaces of the two clamping elements are each distributed over the periphery at an angular distance of approx. 90. This results in a very uniform and syrnmetrical distribution of the clamping force on the 30 clamping shoulders of the basic holder and the tool holder and, ~imlllt~neously~ a symmetrical contact force distributed over the periphery between the inner taperand the outer taper and between the relevant front faces. This is particularly important because this absorbs the radial stress on the clamping point caused byencircling bending forces.
21~31~2 The unit desi~n~ted in this context as the clamping block, consisting of two clamping elements and a parting element, can be mounted in its assembled state as a unit into its intended position. Equally, it can easily be completely removed for checking and m~inten~nce purposes. It is not necessary to assemble a large number 5 of relatively complicated parts with difficulty inside the basic holder or the machine spindle. The flow of power takes place via the shortest path and almost without any occurrence of lateral forces between the basic holder and the tool holder.
Modifications to the standard tool holder are not necessary.
o To simplify the following embodiments, reference will for the most part only be made to the connection between a basic holder and a tool holder, although a machine spindle can be provided in place of the basic holder, and a tool in place of the tool holder.
15 In one pr~relled embodiment, the parting element is a di~ele,lLial screw which lies inside the two sl~mping elements in oppositely coiled tapped holes. The advantage of this solution is that the clamping elements are inevitably guided when they are parted and drawn together. However, the parting element could also be a parting screw which is screwed into one of the clamping elements and rests against the 20 other, or even a shank taper which is drawn between the clamping elements.
The parting element can be reached with a suitable tool through a radial bore in the basic holder. The parting element is preferably connected via a detachable, non-rotating plug connection with a clamping journal which allows a plug-in tool to be 2s connected and which lies in the radial bore of the basic holder. Furthermore, a second, oppositely positioned bore is preferably provided in the basic holder, in which lies an ejecting journal from which proceeds a centering pin which engageswith play in a front face blind bore in the parting element. The clamping journal and the ejecting journal lie in front face recesses on opposite sides of the standard 30 tool holder. Simultaneously, they serve as drivers for the tool holder.
215~122 The parting element can also take the form of an eccentric cam. This results in the significant advantage that the clamping elements can be fully parted by a rotation of maximum 90, whilst with a di~e. en~ial screw or other parting screw several full rotations may be necess~ry under certain circllm~t~nces. The use of an eccentric5 cam as the parting element is therefore particularly advantageous in those cases where the tool has to be clamped in position in a restricted space or in positions where access is difficult.
However, whilst a dirrerenLial screw can both part and draw together the clamping o elements, if an eccentric carn is used the clamping elements can only be parted. The clamping elements can, for example, be retracted with the aid of jaws which are non-rotabably connected with the eccentric cam, which engage in pockets on the inside of the clamping elements and which pull the clamping elements inwards.
Additionally, or alternatively, the use of a return spring could be considered.
The ejecting journal preferably has a non-circular or cam-shaped section and is disposed in relation to the base of the associated recess in the tool holder in such a way that the tool holder can be ejected from the basic holder with the aid of the radial-outer portion of the flattened part by rotating the ejecting journal.
The clamping journal and the ejecting journal also have the additional function of floatingly guiding the clamping block in the unclamped position in the vicinity of the interface of the basic holder and the tool holder.
25 According to another prerelled embodiment, in one ofthe clamping elements there is at least one ejecting pin which runs through the second clamping element to the opposite side, which, when the clamping block is screwed together, comes into contact via one front face sloping surface with an opposite surface of the tool holder and displaces the tool holder in the direction of ejection Said sloping 30 surface can be a conical tip of the ejecting pin, and the ejecting pin can engage via the thread in the first clamping element and in this way be longit~l-lin~lly adjustable.
21~312~
As the opposite surface in this context, the base of one of the front face recesses in the tool holder could be considered.
According to another p-efe-led embodiment, the front faces of the clamping elements closest to the tool holder can be provided with sloping surfaces which, on being drawn together, run up against the sloping surfaces of a connecting element, possibly a coolant adapter, which displaces the tool holder in the direction of ejection.
If an eccentric cam is used as the parting element, one of the cam surfaces of the eccentric cam can run up against a sloping surface which is rigidly connected with the machine spindle when the clamping jaws are loosened by rotating the eccentric cam, so that the tool holder is ejected in this way.
S The interacting surfaces of at least one clamping shoulder and one pair of clamping jaws are preferably at least partially sloped so that when the clamping elements are radially parted, an axial pull is .cimlllt~neously exerted on the tool holder.
On the sides facing each other, the clamping elements can have at least one recess which allows the passage of at least one coolant pipe through the interface between the basic holder and the tool holder.
Entering in their radial direction into the radial bores of the basic holder which accommodate the clamping journal and the eiecting iournal, there are stud bolts which can be screwed into encircling grooves in the clamping journal and the ejecting journal. In this way, the clamping journal and the ejecting journal can be fixed in the axial direction, without being hindered in their rotation.
With respect to the state of the art, reference is also made to EP-B 0 172 850 and WO 88/05358, which, in a comparable context, disclose the use of di~ele,lLial screws for parting clamping elements. However, said publications relate to solutions which overall are not comparable with the problem posed in this instance, 21~3122 and which overall do not meet the stated requirements.
Other features and advantages of the invention result from the sub-claims.
5 Preferred examples of embo~ nentc of the invention will be described in more detail below with reference to the enclosed drawings, in which Fig. 1 shows a partial cross-section of a basic holder with tool holder and clamping device in the clamped state;
Fig. 2 is a partial cross-section from the left in Fig. 1 and shows the clamping device in the clamped position;
Fig. 3 is equivalent to Fig. 2, but shows the closed position of the clamping block;
Fig. 4 is a part section along the line 4-4 in Fig. 1;
Fig. 5 is equivalent to Fig. 1, but shows a different embodiment of the ejecting device;
Fig. 6 is equivalent to Fig. 2, but shows a front elevation of the embodiment of Fig. 5;
Fig. 7 is a part section along the line 7-7 in Fig. 5;
Fig. 8 shows another embodiment of an ejecting device;
Figs. 9a, b and c depict various cross-sections of the clamping shoulders;
Fig. 10 shows another embodiment of the invention with an 2 1 ~ 2 eccentric cam as the parting element;
Fig. 11 is a section along the line 11 - 11 in Fig. 10;
Fig. 12 is an enlarged top plan view of an eccentric cam;
Fig. 13 shows the clamping device of Fig. 10 in the parted position;
o Fig. 14 is a section along the line 14-14 in Fig. 13;
Fig. 15 is a top plan view of the eccentric cam in the parted position.
Figs. 1 to 3 will be considered first. Fig. 1 shows to the left a basic holder 10, in place of which, as mentioned, there could be a machine spindle, and to the right a tool holder 12. The basic holder 10 has an inner taper 14, which corresponds with an outer taper 16 in the tool holder 12. The outer taper of the tool holder borders on a hollow shank, inside which a clamping shoulder 18, which is inclined at less than 30G, projects according to the aforementioned DIN 69893 standard.
Inside the basic holder 10 there is also a hollow space not design~ted in further detail, in which an inwardly projecting clamping shoulder 20 is located. In the example shown, the clamping shoulder 20 is sloped at less than 30 in the opposite direction to the clamping shoulder 18 of the tool holder.
Inside the hollow space formed by the basic holder 10 and the tool holder 12 there are, at the top and the bottom in Figs. 1 to 3, two clamping elements 22, 24, which are connected via a di~le,lLial screw 26 to a partable clamping block. The thread of the di~elt;ll~ial screw 26 engages via oppositely coiled thread portions 28,30 with corresponding tapped holes (not deei~n~ted) in the clamping elements 22, 24.
Rotating the difrelellLial screw 26 therefore allows the clamping elements 22,24 to be parted or brought together. The clamping elements 22,24 are prevented from 2~3122 g - rotating and mi~ligning themselves by the fact that they abut to the left against an encircling shoulder (not design~ted) inside the basic holder, or are located in the - immediate vicinity thereo In the front elevation of Figs. 2 and 3, the clamping elements 22,24 have an ess~nti~lly rect~n~ r profile and with their two outer corners form four jaws 32,34,36,38, which are shown more precisely in Fig. 1. As Fig. 1 shows, the clamping elements 22,24 are staple-shaped, so that they not only have the jaws 32,34,36,38 to be seen in Fig. 2, but also four corresponding jaws at the axially 0 opposed end, of which jaws 40 and 42 can be seen in Fig. 1. The jaws 32 to 42 form four clamping surfaces on each axial side, which, corresponding with the inclination of the clamping shoulders 18,20, are also inclined at less than 30. It can be seen that by radially parting the clamping elements 22,24, the tool holder 12 is axially drawn into the basic holder 10 and is subsequently also radially parted.
To rotate the di~rellLial screw 26 and thus to part or draw together the clamping elements 22,24, a clamping journal 44 is provided, which lies in a radial bore 46 in the basic holder 10. The clamping journal 44 also runs through a front face recess in the left edge of the tool holder 12, which is prescribed by the aforementioned standard. In this way the clamping journal siml.lt~neously exercises a driver function for the tool holder 12 when the basic holder 10 is rotated. At the radial-inner end of the overall cylindrical clamping journal 44, a hexagon spigot 50 projects inwardly into a corresponding recess (not dçsign~ted) in the bottom front face of the di~erell~ial screw 26. A di~e~ , non-circular cross-section can naturally also be used instead of the hexagonal cross-section. On its radial-outer front face the clamping journal also has a hexagon socket 52 which allows an appropriate tool for rotating the clamping journal 44 to be connected. As shown in Fig. 2, the section of the clamping journal 44 which lies in the basic holder 10 is provided with an encircling groove 54, in which engages a stud bolt 56 which is screwed into the wall of the basic holder 10 perpendicular to the axis of the clamping journal 44. Interacting with the groove 54, the stud bolt 56 fixes the clamping journal 44 in the axial direction, but allows it to rotate.
21~3122 ~o On the side diametrically opposed to the clamping journal 44 there is another radial bore 58 in the wall of the basic holder, in which lies an eiecting journal 60 which is the equivalent of the clamping journal 44. Projecting radially inwards from the inner end of the ejecting journal 60 there is a centering pin 62, which engages with 5 play in a front face bore 64 in the dirreren~ial screw 26 at the upper end thereof in Fig. 1. With the aid of the hexagon spigot 50 of the clamping journal 44 and thecentering pin 62 of the ejecting journal 60, the clamping block consisting of the two clamping elements 22,24 and the di~lenLial screw 26 is held floatingly in the unclamped state (Fig. 3) inside the hollow space ofthe basic holder 10 and the tool o holder 12. As Fig. 2 shows, the ejecting journal 60 is also fixed in the axialdirection by a stud bolt 66. Furthermore, the eiecting journal 60 also lies in a front face recess 68 in the tool holder 12 and thus also serves as a driver for the latter when the basic holder is rotated.
5 A further function of the ejecting journal 60 lies in that its section 70 which lies in said recess 68, shown in Fig. 4 in cross-section, is non-circular and has a flattened side 72 which lies opposite the base of the recess 68. When the ejecting journal 60 is rotated, pressure towards the right in Fig. 1, i.e. in the direction of ejection, is thus exerted on the tool holder 12. For the purpose of effecting this rotation, the 20 ejecting journal 60 is also fitted on its outer front face with a hexagon socket 74.
Finally, Figs. 2 and 3 show that on the facing sides on both sides of the diLre~e~lLial screw 26, the two clamping elements 22,24 have corresponding, semi-circular recesses 76,78,80,82 which complement each other to form a circular hollow space25 when the clamping elements 22,24 are drawn together. These hollow spaces with a circular cross-section serve to accommodate coolant pipes 84,86 which connect a coolant adapter 88 and a coolant distributor 90 which are part of a coolant system, not shown separately, for cooling the tools.
Figs. 5 to 7 are ess~n~i~lly equivalent to Figs. 1, 2 and 4 and will therefore only be explained with regard to the differences.
21431~
These differences relate to the ejecting system for ejecting the tool holder 12 out of - the basic holder 10.
According to Figs. S and 6, screwed adjustably into the upper clamping element 22 - 5 there are two ejecting pins 92,94 which run through the lower clamping element 24 as shown in Figs. 5 and 6 in corresponding bores (not deci~n~ted~. The threaded engagement with the upper clamping elements 22 permits longi~ltlin~l adjustm~nt The bottom ends of the ejecting pins 92,94 are truncatedly sloped, as can be seen in Fig. 6.
It is obvious that when the clamping elements 22,24 are screwed together with the aid of the differential screw 26, the clamping pins 92,94 protrude downwards outof the bottom clamping element 24. In doing so, as Fig. 7 shows, they come into contact, directly bordering on the periphery of the lower clamping journal 44 in the two corners ofthe front face recess 48 ofthe tool holder 12, with the edges ofthe recess. As a result of the sloping surfaces of the trllnc~ted ends of the ejecting pins 92,94, an axial pressure is exerted on the tool holder, which leads to it being ejected. When this ejection procedure takes place, the entire clamping block cannot yield upwardly as in Figs. 1 and 2 since the top portion of the upper clamping element rests against the clamping shoulders.
Fig. 8 is a partial representation relating to Fig. 1, and is limited to showing the two closed clamping elements 22,24 and the coolant distributor 90. The coolant distributor 90 has, in the longitu~in~l central axis of the basic holder and the tool holder, on the side closest to the clamping elements, a tnlnc~ted connecting element 91 which is associated with corresponding recesses (not decign~ted) on the opposite surfaces of the clamping elements 22,24, which, when the clamping elements are drawn together, complement themselves to form a truncated recess.
When the clamping elements 22,24 are drawn together, the corresponding sloping surfaces cause pressure to be exerted on the coolant distributor 90, which as shown in Fig. 1, borders closely against the inner surface of the tool holder, in the direction in which the tool holder is ejected.
Figs. 9a,b and c show vanous cross-sections of the clamping shoulder 20 of the basic holder. The representation shown in Fig. 9c corresponds with that in Figs. 1 21~122 and 4. In Fig. 1, a completely radial clamping shoulder is shown in connection with a correspondingly shaped clamping surface on the clamping elements. Fig. 9b is acombination of the two possibilities and shows a partially sloped, partially radially - shaped clamping shoulder.
s When assembling a tool holder the two clamping surfaces 22,24 are first screwed shut on the block with the aid of the di~~ ial screw. In this state they can be introduced inside the basic holder or the machine spindle. With the aid of the clamping journal 44 and the ejecting journal 60, they are then floatingly f~xed in 0 position. The clamping device can now be operated. In this direction they allow a tool holder to be inserted into the basic holder. The tool holder merely has to be rotated until the clamping journal 44 and the ejecting journal 60 engage in the corresponding front face recesses 48 and 68 of the tool holder. If the clamping journal 44 is now rotated, the two clamping elements move apart in step in the 1S radial direction until the jaws come into contact with the clamping shoulders 18,20 of the tool holder and the basic holder or the machine spindle. By contimling the clamping operation the tool holder is drawn axially inwards into the basic holder.
When this happens clamping pressure builds up on the front face of the basic holder and the tool holder, and sim~llt~neously~ increasing radial pressure which 20 builds up over the clamping surfaces and clamping shoulders, causes the relatively thin-walled taper of the tool holder to widen and press against the inner taper of the basic holder. Once a given torque is att~ined the clamping process ends and a tight connection is formed between the basic holder or machine spindle and the tool holder.
2s The reverse procedure results in loosening. However, since the inner taper of the basic holder and the outer taper of the tool holder are relatively flat, self-locking occurs so that a separation does not automatically take place. Various alternative ejecting devices for the purpose of ejecting have therefore been described above, 30 and the manner in which they operate can be inferred from the pre~ious description.
Figs. 10 to 15 relate to another embodiment of the clamping device of the invention, which differs from the embodiment of Figs. 1 to 6 above all in that the ~1~31~2 -parting element is not a differential screw, but an eccentric cam. The eccentric cam - can be rotated in the manner already described, yet only requires an angle of rotation of maximum 90. Otherwise, the main difference in the construction withrespect to the embodiment described above lies onIy in the fact that the axis of the eccentric cam runs between the two clamping elements, whilst with the differential screw, it runs vertically through the two clamping elements.
Because of the numerous conformities with the first embodiment the individual parts in Figs. 10 to 15 bear reference numerals which correspond with those of the 0 first embodiment but have merely been increased by 100. A further description is therefore largely unnecessary. Parts not present in the first embodiment and which relate to the eccentric cam are desi,en~ted by reference numerals starting from 200.
Figs. 10 and 11 show clamping elements 122,124 in the closed position. An eccentric cam 200 which is shown in Fig. 12 on its own and slightly enlarged, but in the position of Fig. 10, has an elongated shape with two parallel edges 202,204 and two cam surfaces 206,208. The gap between the straight edges 202,204 is much smaller than the gap between the cam surfaces 206,208. As shown in Figs.
10 to 12, the eccentric cam 202 lies flatly, ie. with the top and bottom edges 202,204 between the clamping elements 122,124 so that the latter can be displaced inwards, thereby releasing the tool holder. The clamping elements will not of course move inwards, ie. towards the axis of rotation of the arrangement, of their own accord since they can be held self-lockingly against the clamping shoulders 118,120 and the bottom clamping element at least will remain in the bottom 2s position due to gravity. Therefore, to draw them together, there may be springs, rubber bands or suchlike, whose pulling force may not under certain circumct~nces be sufficient to overcome the self-locking forces on the clamping shoulders.
Therefore, according to the invention, jaw discs 210,212 are non-rotatably secured to the axis of rotation of the eccentric carn on both the front faces thereof. The jaw discs have two oppositely positioned radially projecting jaws 214,216 which, when the eccentric cam is rotated in the unclamping direction, ie. approximately anti-clockwise in Fig. 10, engage in pockets 218,220 on the `~ 214~1~2 radial-inner side of the clamping elements 122,124. A portion of the pockets - 218,220 is undercut and in this manner they forrn shoulders 222,224 against which the jaws 214,216 abut on anti-clockwise rotation in Fig. 10, so that the clamping - elements are driven inwards.
From Fig. 12 it can be seen that the two carn surfaces 206,208 slope very flatly so that when the cam surfaces interact with the insides of the clamping elem~nt~ 122, 124, self-locking occurs.
o Figs. 13 and 15 are equivalent to Figs. 10 to 12, but show the clamping device in the clamped position. In this case the eccentric cam 200 is positioned vertically in Figs. 13 and 15. The jaws 214,216 point upwards and downwards. The clamping elements 122,124 engage in the manner already described behind the clamping shoulders 118,120 of the basic holder and the tool holder.
To eject the tool holder 112 where an eccentric cam 200 is used as the parting element, there can be a sloping surface 226 (Fig. lS) which is rigidly connectedwith the tool holder 112, which the carn surface runs up against when the eccentric cam is loosened, so that the tool holder is ejected. As shown in Fig. 15, the sloping surface is contrived at the end of a pin 228 which is screwed into the coolant distributor 190.
Claims (19)
1. Clamping device for connecting basic holders or machine spindles with tool holders or tools for machining, with partable staple-shaped clamping elements (22,24;122,124) which, with radially outwardly projecting clamping jaws (32,34,36,38,40,42; 132,134,136,138,140,142) engage behind clamping shoulders (18,20; 118,120) inside the machine spindle (10;110) and the tool holder (12;112), characterized in that 2 clamping elements (22,24; 122,124) are connected with the aid of a parting element (26,200) to a clamping block whose outer diameter in the closed position is smaller than the smallest inner diameter of both the machine spindle (10; 110) and the tool holder (12; 112), and in that the clamping elements (22,24; 122,124) each have two clamping surfaces on both sides which are disposed such that the four clamping surfaces of the two clamping elements are each distributed over the periphery of the clamping shoulders (18,20; 118,120) at angular distances of approx. 90°.
2. The clamping device of claim 1, characterized in that the parting element (26,200) can be rotated through a radial bore (46;146) in the machine spindle (10;110).
3. The clamping device of claim 2, characterized in that the parting element (26,200) is connected via a datachable, non-rotating plug connection with a clamping journal (44;144) which allows a plug-in tool to be connected and which lies in the radial bore (46; 146) of the machine spindle (10; 110).
4. The clamping device of claim 3, characterized in that a second radial bore (58; 158) is provided in the machine spindle (10;110) on the opposite side to the first bore (46;146), in which lies an ejecting journal (60;160) from which proceeds an aligning pin (62;162) which engages with play in a front face blind bore (64,164) in the parting element (26,200).
5. The clamping device of claim 4, characterized in that the clamping journal (44;144) and the ejecting journal (60;160) lie in front face recesses (48,68) onopposite sides of the tool holder (12,112).
6. The clamping device of claim 5, characterized in that in the unclamped position, the clamping block (22,24,26,200) is held floatingly by the clamping journal (44;144) and the ejecting journal (60;160) within the interface of the machine spindle (10;110) and the tool holder (12;112).
7. The clamping device of claims 5 or 6, characterized in that the ejecting journal (60) has a non-circular section (70), which is disposed in relation to the base of the associated recess (68) in the tool holder (12) in such a way that the tool holder (12) can be ejected out of the machine spindle (110) by rotating the ejecting journal.
8. The clamping device of one of claims 1 to 7, characterized in that the clamping elements (22,24) on the side closest to the tool holder (12) have at least one sloped surface which, when the clamping elements are drawn together, interacts with a corresponding sloped surface (91) in the tool holder or a connecting element (90) connected to the latter and exerts pressure on the tool holder in the direction of ejection.
9. The clamping device of one of the preceding claims, characterized in that the interacting surfaces of at least one of the clamping shoulders (18,20; 118,120) and of one pair of clamping jaws (32,34,36,38,40,42; 132,134,136,138,140,142) are at least partially sloped.
10. The clamping device of one of claims 4 to 9, characterized in that contrived in the radial bores (46,58; 146,158) in the wall of the machine spindle there is a tapped hole for a stud bolt (56,66; 156,166) which engages in an encircling groove (54;154) in the clamping journal (44;144) and the ejecting journal (60;160).
11. The clamping device of one of the preceding claims, characterized in that the parting element is a differential screw (26) with two oppositely coiled thread portions (28,30) which each engage in corresponding inner threads in the clamping elements (22,24).
12. The clamping device of claim 11, characterized in that the clamping elements (22,24) on the facing surfaces have at least one recess (76,78,80,82) which permits the passage of at least one coolant pipe (84,86) through the interface between the machine spindle (10) and the tool holder (12).
13. The clamping device according to one of claims 10 to 12, characterized in that in one of the clamping elements (22) there is at least one ejecting pin (92,94) running through the second clamping element (24) to the opposite side, which, when the clamping block (22,24,26) is drawn together, runs up with one front face sloped surface against an opposite surface in the tool holder (12) and displaces the tool holder in the direction of ejection.
14. The clamping device of claim 13, characterized in that the ejecting pin (92,94) has a conical tip and is held by the thread engaging in the first clamping element (22) such that it can be longitudinally adjusted.
15. The clamping device of claims 13 or 14, characterized in that the opposite surface is the edge of the base of one of the front face recesses (48) in the tool holder.
16. The clamping device of one of claims 1 to 10, characterized in that the parting element is an eccentric cam (200) positioned between the clamping elements (122,124).
17. The clamping device of claim 16, characterized in that connected with the eccentric cam (200) there are at least two radially projecting jaws (214,216) which engage in such a way in undercut pockets (218,220) on the inside of the clampingelements (122,124) that when the eccentric cam (200) is loosened, they exert a radially inwardly directed pulling effect on the clamping elements (122,124).
18. The clamping device of claims 16 or 17, characterized in that in the trajectory of one of the cam surfaces (206,208) of the eccentric cam (200) there is a sloped surface (226) connecting with the tool holder, against which the cam surface (206,208) of the eccentric cam (200) runs up when it is rotated further to eject the tool holder (112).
19. The clamping device of claim 18, characterized in that the sloped surface is contrived on a pin (228) which proceeds from a coolant distributor (190) inside the tool holder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4228558.5 | 1992-08-27 | ||
| DE4228558A DE4228558C1 (en) | 1992-08-27 | 1992-08-27 | Clamping device for tool holders |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2143122A1 true CA2143122A1 (en) | 1994-03-17 |
Family
ID=6466592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002143122A Abandoned CA2143122A1 (en) | 1992-08-27 | 1993-08-26 | Clamping device for tool holders |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0656820A1 (en) |
| JP (1) | JPH08500779A (en) |
| KR (1) | KR950702886A (en) |
| CA (1) | CA2143122A1 (en) |
| DE (1) | DE4228558C1 (en) |
| WO (1) | WO1994005450A1 (en) |
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| DE19907026A1 (en) * | 1999-02-19 | 2000-08-24 | Komet Stahlhalter Werkzeug | Device for detachably connecting tool to machine spindle includes tensioning mechanism with operating nut screwed onto externally threaded connecting sleeve and converting axial movement to radial movement of tension element |
| DE102004009217A1 (en) | 2004-02-12 | 2005-09-01 | Gühring, Jörg, Dr. | Clamping element for tool clamps |
| CN100457387C (en) * | 2007-02-06 | 2009-02-04 | 南通纵横国际股份有限公司 | Rotating floor braking device for rotor of four-axle linkage machine tool |
| US8033766B2 (en) | 2008-05-09 | 2011-10-11 | Kennametal Inc. | Tool holder with ball clamping mechanism |
| DE102010013156A1 (en) * | 2010-03-27 | 2011-09-29 | Volkswagen Ag | Tensioning arrangement for fastening tool holder at receiving device in machine tool, has supporting element whose radial displacement is allowed due to radial displacement of clamping element, and retaining portions inserted into retainers |
| CN113927322B (en) * | 2021-10-12 | 2023-03-14 | 山东信通电子股份有限公司 | Pipe fitting positioning device and equipment for processing pipe fitting |
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| US3022084A (en) * | 1960-08-04 | 1962-02-20 | Beaver Tool & Engineering Corp | Tool holder and tool shank construction |
| EP0101917B1 (en) * | 1982-07-30 | 1986-05-28 | Gerhard Rall | Cutting tool |
| US4573824A (en) * | 1984-02-10 | 1986-03-04 | Gte Products Corporation | Apparatus for coupling a first member to a second member |
| DE3433878A1 (en) * | 1984-09-14 | 1986-03-27 | August Beck GmbH & Co, 7472 Winterlingen | AXIAL CLAMP CONNECTION |
| EP0193020B1 (en) * | 1985-03-01 | 1990-11-28 | Fried. Krupp Gesellschaft mit beschränkter Haftung | Tooling device with an exchangeable tool head |
| US4726268A (en) * | 1987-01-27 | 1988-02-23 | Kennametal Inc. | Clamping apparatus for holding a toolholder shank |
| DE3837007A1 (en) * | 1988-10-31 | 1990-05-03 | Krupp Widia Gmbh | CLAMPING DEVICE FOR CONNECTING THE TOOL HEAD AND TOOL HOLDER TO MACHINE TOOLS |
| DE3904259A1 (en) * | 1989-02-13 | 1990-08-16 | Guehring Gottlieb Fa | COUPLING FOR DETACHABLE FIXING OF COMPONENTS ON CORRESPONDING CARRIER PARTS |
| DE4028775C1 (en) * | 1990-03-28 | 1991-07-25 | Ott Maschinentechnik Gmbh, 8960 Kempten, De | |
| DE4221735C2 (en) * | 1992-07-02 | 1997-05-22 | Grob Gmbh & Co Kg | Hollow shaft attachment for a tool holder |
-
1992
- 1992-08-27 DE DE4228558A patent/DE4228558C1/en not_active Expired - Fee Related
-
1993
- 1993-08-26 EP EP93919194A patent/EP0656820A1/en not_active Withdrawn
- 1993-08-26 WO PCT/EP1993/002313 patent/WO1994005450A1/en not_active Application Discontinuation
- 1993-08-26 CA CA002143122A patent/CA2143122A1/en not_active Abandoned
- 1993-08-26 KR KR1019950700757A patent/KR950702886A/en not_active Application Discontinuation
- 1993-08-26 JP JP6506843A patent/JPH08500779A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| WO1994005450A1 (en) | 1994-03-17 |
| KR950702886A (en) | 1995-08-23 |
| DE4228558C1 (en) | 1994-02-10 |
| JPH08500779A (en) | 1996-01-30 |
| EP0656820A1 (en) | 1995-06-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |