WO1994025221A1

WO1994025221A1 - Clamping device for fast axial mounting of tools, especially the disk-shaped ones

Info

Publication number: WO1994025221A1
Application number: PCT/SI1994/000005
Authority: WO
Inventors: Filip Kozelj
Original assignee: Filip Kozelj
Priority date: 1993-04-29
Filing date: 1994-04-26
Publication date: 1994-11-10
Also published as: AU6764494A; EP0702614A1

Abstract

The proposed invention is a clamping device for fast axial clamping of tools, especially disk-shaped ones, for example grinding wheels (10) for portable angle grinders, which is screwed onto the the threaded end (4) of the driving shaft (1), at the outer side, in such a way that together with the opposite lying flange (6), which is non-rotationally linked with the driving shaft (1), it presses against the grinding wheel (10). It consists of two flanges (14) and (12), lying opposite each other, having teeth (19) and (20) turned one against the other, with left screw planes (21) and (22) over which the clamping force is transmitted. In the radial direction, the flanges (14) and (12) are fitted with extruding thumbs (24) and (23), which with their opposite lying planes (39) and (38) form a 2 ≡ angle and between which there are extruded parts (27) which, in the longitudinal direction, touch wedge-shaped recesses (32) at a β angle. The recesses (32) are on a ring (28) which, in the longitudinal direction, closes up the space between the flanges (14) and (12). The ring (28) is fitted with positioning thumbs (35) which rest upon positioning projections (37), these being rigidly linked with the flange (14), and catching thumbs (33). Between the catching thumbs (33) and the extruding thumbs (24) there are pressure springs (34).

Description

CLAMPING DEVICE FOR FAST AXIAL MOUNTING OF TOOLS, ESSPECIALLYTHE DISK-SHAPED ONES

The present invention of clamping device for fast axial mounting of tools, esspecialy the disk-shaped ones complies to classes B24B 45/00 and B 24B 23/02 of the International Patent Classification.

The proposed solution of clamping device solves the problem of fast clamping and releasing tools, especially disk-shaped tools (e.g. grinding wheels, circular saw blades) manually, without using an additional tool, and by applying minimum force.

A known solution is described in DE-OS3644440. In this solution the tool (grinding wheel) is pressed between the outer flange, which is screwed onto the end of the driving shaft of an angle grinder, and the inner flange, which transmits the torque and which is axially shiftable and loaded over a ring-shaped part with the axial force of the grinding wheel. The ring-shaped part has a non-rotational link with the driving shaft. Both parts have the left screw surfaces facing each other, with the gradient angle lying in the self-sliding area. The mutual slide of both parts and thereby the rotation of the inner flange towards the ring-shaped part is blocked by a special lever which is installed in the radial direction and which with one side surface rests on the ring-shaped part while the other rests on a catch on the inner flange. By moving the lever away from the catch area, the inner flange and the ring-like part slide across the slanted surfaces, thereby rotating one against the other and causing the release of a force between the outer and the inner flange, which makes it possible to manually unwind the outer flange and exchange the grinding wheel without using additional tools.

The above described solution has several drawbacks:

- The lever which when moved releases the clamping force of the grinding wheel, is located in the inner side of the tool and it is therefore hard to access.

- The lever reaches in the radial direction above the cylindrical surface which, while the machine is in operation, rotates and can in a certain moment hit the workpiece, which would cause a shock to the machine. This can be dangerous for the operator.

- Due to a relatively small gradient angle of the slanted surfaces it may occur, in case that the threads on the driving shaft and the outer flange are rusty and therefore the frictional force is increased, that the sliding force on these surfaces may be too small to overcome the frictional force between the threads, an exchange of the grinding wheel may no longer be possible without an additional tool.

In the case of a relatively high gradient angle, however, the force applied on the deblocking lever is too strong to allow it to be moved by hand, and tool exchange is again impossible without the use of an additional tool.

Tools, especially the disk-shaped ones, are held onto the driving shafts of machines the frictional force which is attained by pressing the tool between two flanges placed at the end of the driving shaft. The inner flange is in a non-rotating form-to- form link with the driving shaft, the outer flange being screwed onto the threaded end of the driving shaft in such a way that the axial force of the screw joint presses against the tool, and over the tool the force is transmitted to the inner flange. The frictional force occurring between the contact surfaces of the flanges and the tool transmits the torque and the rotation from the driving shaft to the tool. The influential parameters and the dimensions of the flanges and the driving shaft, respectively, are made such that in no case a slide of the tool between the flanges may occur. Should the torque on the tool increase considerably (e.g. due to a forced blocking of the tool), an additional self-tightening of the outer flange occurs whereby the axial force and thereby the frictional force between the flanges and the tool increase and block the tool from sliding. As such blockings can sometimes be very violent, it is clear that the self-tightening torque of the outer flange in such a case is very strong, in particular when taking into account that the screw surfaces may be rusty, which additionally hinders the unscrewing of the flange, and that in such a case it is very difficult to unscrew the flange, despite the use of an additional tool. The clamping device under the invention allows manual exchange of tools by applying a minimum force and without the use of an additional tool. The clamping device under the invention will be further explained with drawings accompanying the description of the device.

The drawings represent:

Fig. 1 Reduced longitudinal cross-section through a clamping device mounted on the driving shaft of a portable angle grinder.

Fig. 2 Reduced partial cross-section along the D-D line of

Fig. 1.

Fig. 3 Reduced partial cross-section along the A-A line of

Fig. 2 developed into the plane.

Fig. 4 Reduced partial cross-section along the B-B line of

Fig. 2.

Fig. 5 Reduced partial cross-section along the C-C line of

Fig. 2.

Fig. 6 Reduced longitudinal cross-section through the

second variant of a clamping device mounted on the driving shaft of a portable angle grinder

Fig. 7 Reduced partial cross-section along the E-E line of Fig. 6

Fig. 8 Reduced longitudinal cross-section of the third variant of a clamping device mounted on the driving shaft of a portable angle grinder

Fig. 9 Reduced partial cross-section along the F-F line of the variant shown in Fig. 8

Fig. 10 Reduced partial cross-section along the H-H line of the variant shown in Fig. 9

Fig.11 Demonstration of constructional solution I of blocking the ring 28 in the first variant

Fig. 12 Demonstration of constructional solution II of blocking the ring 28 in the first variant

Figure 1 shows a reduced longitudinal cross-section through the driving shaft 1 of a portable angle grinder, the shaft ending up in a threaded piece 2 whose diameter is smaller than the diameter of the driving shaft 1. The threaded piece 2 consists of a cylindrical part 3 and a threaded end 4 of the driving shaft 1. A flange 6 rests on the ring-shaped surface 5 between the driving shaft 1 and the threaded piece 2, the flange 6 being linked with the driving shaft 1 in a non-rotating form-to-form way. The centering hole on the flange 6 touches the cylindrical part 3 of the threaded piece 2, whereby it is centred, in radial direction, to the driving shaft 1. Concentrically to the centring hole 7 lies the outer centring surface 8 of the flange 6 on which a grinding wheel 10 is centred over the centring hole 9. On the opposite side of the flange 6, the clamping device 11 under present invention is screwed onto the threaded piece 2 in such a way that that the grinding wheel 10 is pressed between the flange 6 and the clamping device 11. The clamping device 11 has two flanges 12 and 14 which face each other in the axial direction. The inner flange 12 which presses against the grinding wheel 10 is relatively flat and fitted with a centring hole 13 whose diameter increases gradually on the side of the grinding wheel to a diameter slightly bigger than the diameter of the centring hole 9 on the grinding wheel 10. The outer flange 14 consists of a relatively flat part and a central tubular part 15 which reaches through the hole 13 of the_. inner flange 12. At the place where the hole 13 changes its diameter there is a recess 16 on the ring-shaped part 15 into which a circlip 17 is inserted in order to stop both flanges from moving apart, joining them in this way into a whole. The outer flange 14 has a nut hole in its centre with an inner thread 18 which engages the outer thread of the threaded piece 2. In the axial direction both flanges 14 and 12 are fitted with teeth 19 and 20 turned towards each other or towards the interior of the clamping device 11. The teeth 19 and 20, when shown in a longitudinal cross-section have the approximate shape of a right-angled triangle whose longest side is slanted by a ϊ angle towards the plane lying rectangularly to the^' driving shaft's 1 axis, and since the teeth are wider in the radial direction, left screw planes 21 and 22 are formed making up one plane of the teeth 19 and 20. Over the screw planes 21 and 22 the clamping force of the outer flange 14 screwed onto the driving shaft 1 is transmitted to the inner flange 12, which presses against the grinding wheel 10. The grinding wheel 10 rests against the flange 6 which rests, via the ring-shaped surface 5, against the driving shaft 1 , where the clamping force is intercepted.

Both flanges 12 and 14 have extruding thumbs 23 and 24 running in the radial direction. The extruding thumbs 23 are linked in the longitudinal direction with the inner flange 12, while in the radial direction they reach from the outer surface 25 of the teeth 20 outwards. The extruding thumbs 24 are linked in the longitudinal direction with the outer flange 14, while in the radial direction they reach from the outer surface 26 of the teeth 19 outwards. Between the extruding thumbs 23 and 24 extruded parts 27 are placed which have the shape of small cylinders or wedges with a semi-circular ending on the thicker side. The extruded parts 27 touch the extruding thumbs 23 and 24 on the surfaces 38 and 39 facing each other in the direction of rotation.

Between both flanges 12 and 14 a ring 28 reaches in the longitudinal direction with the thickness of its wall decreasing at both ends. Over the ring-shaped surfaces 29 and 30 thus formed reach the surfaces 43 and 42 of the flanges 12 and 14 which stop the ring 28 from falling out in the longitudinal direction. The outer surface 41 of the ring 28 is ribbed, which facilitates the screwing and unscrewing of the clamping device 11. On the inner surface 31 of the ring 28 there are longitudinal recesses 32 running approximately tangentially to the inner surface 31. On the longitudinal recesses 32 rest the extruded parts 27, which can therefore not be moved outwards in the radial direction. In the radial direction, the ring 28 is fitted with relatively narrow catching thumbs 33 which reach in the radial direction approximately to the outer surface 25 and 26 of the teeth 19 and 20. Between the catching thumbs 33 and the extruding thumbs 24 there are pressure springs 34. A little further clockwise (arrow 4) the ring 28 is in radial direction fitted with positioning thumbs (35) which are a little shorter than the catching thumbs 33. Between the thumbs 33 and 35 reach in longitudinal direction unscrewing projections 36 which are fixedly linked with the outer flange 14. The positioning thumbs 35 rest in the direction of rotation on positioning projections 37 which are also fixedly linked with the outer flange 14. The mutual position of the recesses 32 towards the positioning thumbs 35 and the mutual position of the positioning projections 37 towards the extruding thumbs 24 is defined so that a angle is formed between the common tangents running through the contact points on the extruded parts 27 and recesses 32 and the perpendiculars to the symmetrals running radially through the centre of the extruded part 27. This angle being a little smaller than the self-sliding angle. The mutual position and shape of contact surfaces 38 and 39 on the extruding thumbs 23 and 24 and the position of the recesses 32 are defined by the tangents to the surface of the extruded parts 27 running through the common contact points on the extruded parts and the surfaces 38 and 39 on the extruding thumbs 23 and 24 forming a 2_<£ angle. The angle c is a little bigger than the self-sliding angle. The contact surfaces 38 and 39 are shaped in such a way that the 2 cC angle is preserved even at a slight mutual turn of the flanges 12 and 14. Mutual position of the extruding thumbs 24 towards the position of the teeth 19 and of the extruding thumbs 23 towards the position of the teeth 20 is defined with the teeth 19 and 20 being slightly separated in the direction of rotation.

There are washers on all openings through which humidity and dust could penetrate into the interior of the clamping device 11.

The mutual position of the outer ring 28 towards the flanges 12 and 14 is maintained by the springs 24 which push the ring 28 in the direction of rotation until the positioning thumbs 35 fit into the positioning thumbs 37. When the clamping device 11 is screwed clockwise (arrow 44) onto the driving shaft 1 , the torque is transmitted over the positioning thumbs 35 and the positioning projections 37 to the outer flange 14, while via the teeth 19 and 20 it is also transmitted to the inner flange 12. When the inner flange 12 sits with its outer surface 40 onto the grinding wheel 10, an axial force appears on it which is transmitted over the screw surfaces 22 and 21 to the outer flange 14, and from there over the inner threads 18 to the threaded piece 2 or the driving shaft 1. Likewise, the axial force appears on the flange 6, and this too is transmitted over the surface 5 to the driving shaft 1. Being transmitted over the screw surfaces 21 and 22, the axial force causes, owing to the gradient angle tf of these surfaces in the self-sliding area, that the teeth 19 try to slide alongside the screw surfaces 21 and 22 and thereby to turn the outer flange 14 anti-clockwise (arrow 45). This turn is prevented by the extruded parts 27 against which rest the extruding thumbs

24 and 23. Since the extruding thumbs 24 and 23 with their contact surfaces 39 and 38 form wedge-shaped spaces with a 2cC angle, and since the ϋ angle is bigger than the self-sliding angle, the extruded parts 27 try to move radially outwards. This shift is prevented by the ring 28 with its recesses 32 against which rest the extruded parts 27. There is, between the perpendiculars to the radial symmetral of the extruded parts 27 and the common tangents in the contact points of the extruded parts 27 and the recesses 32 a β angle which is, however, smaller than the self-sliding angle, therefore there is no self-sliding of the extruded parts 27 alongside the recesses 32, and thereby no sliding of the teeth 19 along the screw surfaces 21 and 22.

In order to change the grinding wheel 10, it is necessary to turn the ring 28 slightly anti-clockwise (arrow 45). Jn this way the extruded parts 27 slide alongside the recesses 32. As the recesses 32 are wedge-shaped, the extruded parts 27, in the same time as they slide alongside the recesses 32, also move radially outwards. With this the motion of the flanges 14 and 12 is released in the direction of the turn. The teeth 19 slide alongside the screw surfaces 21 or 22, whereby the flange 14 moves slightly anti-clockwise (arrow 45). With this the axial force between the inner threads 18 of the flange 14 and the outer threads of the threaded piece 4 is released, whereby the frictional force between them disappears along with the frictional force between the inner flange 12 and the grinding wheel 10, and the clamping device 11 can be unscrewed manually, without special effort, and the grinding wheel 10 can be changed.

Figure 6 shows the second variant of the clamping device (111). All parts corresponding to the first variant are marked with the same numbers plus 100, and in order to avoid repetition, the descriptions of the first variant should be taken into account.

The second variant of clamping device 111, which is illustrated in figures 6 and 7, differs from the first variant in that the release of axial pressure is achieved through a shift of the ring 128 in the longitudinal outward direction (arrow 151). In order to facilitate the grip of the ring 128 by the hand the latter is fitted approximately at the level of the outer flange 114 with a ring-shaped projection. The shift of the ring 128 outwards is more favourable for e.g. clamping the grinding wheels 110 whose clamping surface is recessed and access to to the surface 141 of the ring 128 is difficult.

Such direction of releasing the axial pressure is achieved with the inner surface 132 of the ring 128 being shaped approximately as the curved surface of a truncated cone having its wider part on the side of the grinding wheel 110 and the lh angle against the cone axis. To the inner surface 132 of the ring 128 also the shape of the extruded parts 127 is adapted, the extruded parts having with this variant the shape of balls or of wedges with a semi-global ending on the wider side. The ring 128 is fitted in the longitudinal direction with the catching projections 152 which reach between the flanges 114 and 112. The catching projections 152 are fitted in the longitudinal direction with recesses 153 which end up on the inner flange's side with partition walls 154. Into the recesses 153 reach, in the longitudinal direction, catching thumbs 155 of tubular shape with a closed hole at the flange's 114 side. In this way the ring 128 and the outer flange 114 are fixedly linked in the direction of rotation. In the catching thumbs 155 there are pressure springs 156 which, with the one end, press against the outer flange 114, and with the other side, to the partition walls 154 which rest on the inner flange 112. The springs force is intercepted at the circlip 117.

To change the grinding wheel 110 it is necessary to move the ring 128 a little in the longitudinal direction and outwards (arrow 151). In this way the motion of the extruded parts 127 in the radial direction outwards is released, and thereby the turn of the flange 114 towards the flange 112, and thereby the release of the axial or fixing force.

Figure 12 shows the constructional solution II of blocking the ring 28. During the rotation of e.g. a grinding wheel, and even more so during its stopping, various vibrations occur, also in the direction of rotation. Such vibrations may cause, in a certain case, especially at a smaller spring force, a gradual shift of the ring 28 in the anti-clockwise direction, and thereby an automatic release of the clamping device, which, however is not permissible, as it may cause automatic unscrewing of the clamping device and possible breaking of the grinding wheel. To prevent this from happening, the ring 28 may be linked with the inner flange 12 or the outer flange 14 for example with a flat spring 46. On the other side the flat spring 46 is fixed with e.g. the outer flange 14 and reaches into the recess 47 on the ring 28. With this the automatic turn of the ring 28 is prevented, which means an enhanced automatic release of the clamping device itself. Prior to turning the ring 28, the spring 47 should be lifted, which makes it possible to turn the ring 28. As the ring 28 is, through this additional solution in the form of the spring 47, blocked against turning, the angle may be greater than the self-sliding angle, which upon the release of the ring 28 facilitates or even causes a self-turn.

Figure 11 shows the constructional solution I of blocking the ring 28. The blocking of the ring 28 may be also carried out with an additional ring 48, which reaches over the ring 28. A pressure spring 49 is placed inside the ring 48, which rests with the one side against the ring 28 and with the other against the ring 48. The ring 48, which is linked , in the direction of rotation, with the ring 28 and has a projection 50 in the form of a nose reaching into the recesses 51 and 52 of the ring 28, or of the outer flange 14. Through moving the ring 50 upwards (arrow 53) the turn of the ring 28 is released and thereby the deblocking of the clamping device and of the grinding wheel can be achieved.

The flanges 212 or 214 may be fitted with teeth 219, 220 having right screw surfaces. Because of this also the linking of the extruding thumbs changes in such a way that the extruding thumbs 223 are linked with the outer flange 214, whereas the extruding thumbs 224 are linked with the inner flange 212. In this way, when a slide occurs, the extruding thumbs 223 and 224 move closer to each other and thus push out the extruded part 227.

The axial force transmitted in this case over the right screw surfaces 221 and 222 makes the teeth slide alongside these screw surfaces, and thereby press against the outer flange 214, thus trying to turn the outer flange 214 clockwise. The teeth 219 slide alongside the screw surfaces 221 or 222, while the flange 214 turns clockwise.

The operation of the clamping device itself is similar to the operation of a device whose teeth are equipped with left screw surfaces, except that the in the case of the right screw surfaces the flange 214 rotates clockwise, and the difference between the gradient (slope) of the winding surfaces 221 or 222 and the gradient of the threads 218 releases the flange 214.

The recesses 232 can also be shaped in such a way that the initial angle at the turn of the ring 228 anti-clockwise (arrow 45) can increase, stay unchanged, or decrease, it can also be 0° or a combination of the above values. The increase of the β angle decreases the necessary force for the turn, whereas the decrease of the angle causes a lesser movement of the extruded parts 227 at the same angular turn of the ring 228 and thereby a bigger turn of the ring 228 until the clamping device is released.

This solution is useful especially with the clamping devices which are screwed at a very small torque, while with a fast increase of the /2» angle in the combined shape of the recess 332, the release of the clamping device 211 is achieved at always the same turn of the ring 228.

The inner surface 232 in the second variant has the shape of the curved surface of a truncated cone with the wider part on the side of the grinding wheel with its angle towards the axis of the cone. The inner surface 232 can also be shaped in such a way that the angle increases upon the move of the ring upwards. With this a greater move of the extruded parts 227 is achieved while the move of the ring 228 remains the same, which decreases the necessary move of the ring 228 and thereby indirectly also decreases the height of the clamping device 211.

The constructional solution of the third variant, which is shown in Figures 8 and 9, represents an improved combination of the first and the second variant.

The release of the clamping device 211 in the proposed constructional solution is achieved by moving the ring 228 upwards in the direction of the arrow 281. To this purpose, the ring 228 is fitted, approximately at the level of the outer flange 214, with a ring-shaped projection 282. Upon the releasing of axial pressure the ring 228 turns also slightly anti-clockwise in the direction of the arrow 245. Through such constructional solution it is possible to achieve the release of the clamping device 211 with the move of the ring 228 upwards, even at a very low height of the clamping device 211. This is made possible through specially shaped recesses 232 on the ring 228, where in a cross-section between the perpendiculars to the symmetral of the extruded parts 227 and the recesses 232, in the contact points, there is a 6 angle, and in a longitudinal cross-section between the recesses 232 and the straight lines running through the contact points and perpendicularly to the cross-sectional plane, there is a c angle. The catching thumbs 233 are fitted, in the longitudinal direction, with blind holes 283 with the opening at the side of the outer flange 214, in which there are pressure springs 284, the other side of which rests against the outer flange 214 in such a way that the ring 228 presses against the inner flange 212. At the side of the inner flange 212 the catching thumbs 233 are fitted with cone- shaped projections 285 with a £ angle reaching into the blind holes 286 on the inner flange 212, whose walls are cut off at a € angle. The extruded parts 227 are shaped so as to fit, as well as possible, onto the contact surfaces 238 and 239 on the extruding thumbs 223 and 224, and into the recesses 232 on the ring 228. The extruded parts 227 may have the shape of a globe, a ball- or cylindrical-ended wedge, a cylinder, or they can also have a combination of the above shapes.

The angles J, < , £ are functionally interconnected and can assume various values. The S angle can be bigger than the automatic sliding angle, or it can be smaller. In the first case, a circumferential force appears on the ring 228 due to the radial force applied by the extruded parts 227 to the recesses 232, this circumferential force acting in the anti-clockwise direction (arrow 45), trying to turn the ring 228 in this direction. This turn is partly prevented by the springs 234 and the projections 285 which link the ring 228 with the inner flange 212 and prevent the al turn of the mentioned parts. To change for example grinding wheel 210 the ring 228 should be moved slightly outwards in the longitudinal direction in the direction of the arrow 281, so that the projections 285 reach out of the holes 286. Such a shift is strongly facilitated by making the S angle slightly smaller than the self-sliding angle. Due to the circumferential force applied on the ring 228, a frictional force appears between the projections 285 and the holes 286, where the circumferential force is intercepted. The projections 285 and the holes 286 are formed with the € angle, which is defined with the ring 228 in the self-holding area in upwards movement in the direction of the arrow 281. As the 6 angle is greater than the self-sliding angle, the ring 228 turns anti-clockwise in the direction of the arrow 245. With this the axial force is also released.

When the angle S is smaller than the self-sliding angle the ring 228 should upon changing the grinding wheel 210 be both moved upwards in the direction of the arrow 281 and slightly turned anti-clockwise. In the case where the β angle equals 0°, the 3 and £ angles are relatively big, which causes the appearance of a relatively strong longitudinal force upwards in the direction of the arrow 281 , which helps to overcome the frictional force between the extruded parts 227 and the recesses 232 and facilitates the moving of the ring 228 upwards in the direction of the arrow 281. In order to achieve efficient operation of the improved clamping device for fast axial clamping of the tool according to the invention, the Λ , S , € angles must be chosen so that it is as light as possible to move the ring upwards, and the exchange of the grinding wheel 210 is easy and simple.

The advantages of the clamping devices 11, 111, 211 described above are in their reliable operation and very small force necessary to change the grinding wheels 10, 110, 210. It is a well-known fact that when using angle grinders in the open air or in humid places, the screw surfaces 18 may get rusty, which considerably increases the frictional force between the threads. Thus it may occur that, despite the release of motion of the flanges 14, 114, 214 and 12, 112, 212 in the direction of the turn, at a relatively small ϊ angle of the screw surfaces 21 or 22, there is no slide alongside these surfaces and the clamping device 11, 111, 211 cannot be unscrewed without the use of an additional tool. The increase of the V angle, on the contrary, increases the force necessary to turn or move the ring 28, 128, 228, and thereby a release of movement of the flanges 14, 114, 214 or 12, 112, 212. The described solution of the clamping device 11, 111, 211 makes it possible, despite a relatively big tf angle, the turn or move of the ring 28, 128, 228 by applying a minimum force. This is achieved with the -AL angle being only slightly bigger than the self-sliding angle, and the angle being only slightly smaller than the self-sliding angle. With the oC angle being relatively small, the force pressing on the extruding thumbs 27, 127, 227 is relatively small in the radially outward direction, and as the ring 28, 128, 228 while being turned or moved actually slides alongside the slope with the 6 angle downwards, and with the β angle being only slightly smaller than the self-sliding angle, it is clear that the force necessary to turn or move the ring 28, 128, 228 is, despite a relatively big angle, relatively small and it can be applied manually. Should there, for certain reasons such as a bad damage or even a break of the threads 18 or the threads on the threaded part 4, not come to a turn of the flange 14 despite the release, because of a relatively big % angle, the teeth 20 slide alongside the screw surfaces 21 and 22, whereby the flange 12, 112, 212 turns slightly clockwise and, likewise, the axial pressure between the threads 18 and the threads on the threaded part is released. Should the damage of the threads 18 or of the clamping device 11 , 111 , 211 be so serious that no turn of the flanges 14, 114, 214 or 12, 112, 212 occurs despite the release, it is necessary to turn the ring 28 anti-clockwise (arrow 45) until the positioning thumbs 35 sit onto the unscrewing projections 36, and by further rotation of the ring 28 unscrew by force the outer flange 14 and the clamping device 11. As in the clamping device 111 , the ring 128 is fixedly linked with the flange 114 in the direction of rotation , by rotating the ring 1 8, we also unscrew by force the clamping device 111.

A further advantage of the described clamping device 11, 111, 211 is in that it is very low and in this way it is not in the way of the user when working with an angle grinder. In addition, the clamping device 11, 111, 211 is very cost-effective, since it has very few component parts.

Claims

WHAT WE CLAIM IS:

1. Clamping Device for fast axial mounting of tools, especially the disk-shaped ones, e.g. grinding wheels 10, 110 and circular saw blades, screwed onto the threaded end 4 of the driving shaft 1 in such a way that it presses in conjunction with the opposite lying flange 6 being non- rotationally form-to-form linked with the driving shaft 1 against the grinding wheel 10, 110, characterized by,

in the longitudinal direction, opposite the inner flange (12, 112), which with its outer surface (40) presses against the grinding wheel (10, 110) and which has a relatively flat shape with a hole (13) in the centre whose diameter gradually slightly increases at the side of the grinding wheel (10, 110), the inner flange (14, 114) which is relatively flat, too, with a central projection (12, 112) of tubular shape reaching through the hole (13) of the inner flange (12, 112), having at the place where the diameter of the hole (13) increases a recession (16) in which there is a circlip (17, 117), and on the inner surface a thread (18) by means of which the outer flange (14, 114) is wound onto the threaded end (4) of the driving shaft (1).

2. Clamping Device as per claim 1 ,

characterized by,

the inner flange (12, 112) is rotationally linked with a central projection (15) and is, relatively towards the outer flange (14, 114), partially movable in the longitudinal direction.

3. Clamping Device as per claims 1 and 2,

characterized by the inner flange (12, 112) and the outer flange (14, 114) are fitted, at that part of the surface which is turned towards the interior of the clamping device (11, 111), in the direction of rotation, with teeth (19) and (20), of approximately saw-like shape, facing one another.

4. Clamping Device as per claims 1 through 3, characterized by the surfaces (21 and 22) of the teeth (19) and (20), which in the axial direction face one another, are parts of left screw planes with the gradient angle being ^ .

5. Clamping Device as per claim 4, characterized by the gradient angle lies deep in the self-sliding area.

6. Clamping Device as per claims 1 through 5, characterized by the teeth (19) and (20) are in the radial direction limited by the surfaces (26) and (25) of approximately equal diameter, and from these two surfaces relatively narrow extruding thumbs (24) and (23) reach outwards in the radial direction, said thumbs being distributed in the direction of rotation and ending in the radial direction at a short distance from the outer surface (42) and (43) of flanges (14, 114) and (12, 112), respectively, and reaching in the longitudinal direction approximately to the level of the teeth (19 and 20).

7. Clamping Device as per claims 1 through 6,

characterized by

the mutual position of the inner flange (12, 112) against the outer flange (14, 114) in the direction of rotation is such that the extruding thumbs (23) and (24) are in pairs, in the direction of rotation, relatively close to one another, while between them there lie extruded parts (27, 127), which touch with their surface the surfaces (39) and (38) lying on the extruding thumbs (24) and (23), and facing each other in the direction of rotation.

8. Clamping Device as per claim 7, characterized by the extruded parts (27) have cylindrical or wedged shape with an approximately semi-circular end at the wider part.

9. Clamping Device as per claim 7, characterized by the extruded parts (127) have the shape of balls or wedges with approximately semi-circular end at the wider part.

10. Clamping Device as per claim 7, characterized by the extruded parts (227) have the shape of balls, cylinders, wedges with ball-shaped or cylindrical ends, or a combination of the above proposed shapes.

11. Clamping Device as per claims 1 through 10,

characterized by the common tangents on the surface of the extruded parts (27, 127) and on the surfaces (39) and (38) in their common points of contact form a 2o£ angle and that the surfaces (39) and (38) are in the vicinity of these points of contact, shaped in such a way that the 2 C angle does not change despite a slight mutual turn of the flanges (14, 114) and (12, 112) and thereby a shift of the extruding thumbs (23) and (24) in the direction of rotation.

12. Clamping Device as per claim 11, characterized by the o angle is slightly bigger than the self-sliding angle.

13. Clamping Device as per claims 1 through 12, characterized by the mutual position of the extruding thumbs (24) towards the teeth (19) in the direction of rotation, and that of the extruding thumbs (23) towards the teeth (20) in the same direction is such that the teeth (19) and (20) are slightly parted in the direction of rotation.

14. Clamping Device as per claims 1 through 13,

characterized by over both surfaces (42) and (43) of the flanges (14) and (12), a ring

(28) reaches having a ribbed outer surface (41), the ring being rotationally linked with the flanges (12) and (14) and slightly shiftable towards them in the longitudinal direction, and the inner surface (31) of which increases in steps on both ends, and over the ring surfaces

(29) and (30) thus formed, reach the flanges (12) and (14).

15. Clamping Device as per claim 14, characterized by the ring (28) is fitted, on the inner surface (31) in the direction of rotation, with longitudinal recesses (32) having in cross- section a wedged shape with a widening in the clockwise direction (arrow 44), and in a certain distance from these, in the same direction, with relatively narrow, radially inwards running catching thumbs (33) which in radial direction end at a short distance from the surface (25) and (26) of the teeth (19) and (20), and a little further on, in the same direction with slightly shorter positioning thumbs (35) of similar shape.

16. Clamping Device as per claims 1 through 15, characterized by between the extruding thumbs (24) and the catching thumbs (33) there are pressure springs (34).

17. Clamping Device as per claims 1 through 16,

characterized by the outer flange (14) has, near the surface (42), longitudinally running positioning projections (37) which are fixedly linked with it and against which rest the positioning thumbs (35), while between the catching thumbs (33) and the positioning thumbs (35), running longitudinally, reach unwinding projections (36), these being fixedly linked with the flange (14), too.

18. Clamping Device as per claims 1 through 17, characterized by the extruded parts (27) touch, in the longitudinal direction, the recesses (32) on the ring (28) and that between the perpendiculars to the symmetrals of the extruded parts (27) and the tangents to the surface of the extruded parts (27), in the contact point's on the recesses (32), there is a angle.

19. Clamping Device as per claims 1 through 13, characterized by a ring (128) reaches over both surfaces (142) and (143) of the flanges (114) and (112), whose outer surface (141) extends, approximately at the level of the outer flange (114), in steps into a ring-shaped projection (157), which is partly shiftable towards them in the longitudinal direction, the inner surface (132) of which has an approximate shape of the curved surface of a truncated cone with the bigger diameter on the side of the inner flange (112), slanted by a & angle towards the axis of the cone whose diameter at both ends increases in steps, and over the ring-shaped surfaces (129) and (130) thus formed, reach the flanges (112) and (114) .

20. Clamping Device as per claims 18 and 19,

characterized by

the β angle is slightly smaller than the self-sliding angle.

21. Clamping Device as per claim 19, characterized by the ring (128) has in its inner surface (132) longitudinally running catching projections (152) reaching between the flanges (112) and (114), with longitudinal recesses (153) which, at the side of the inner flange, end up with partition walls (154).

22. Clamping Device as per claims 1 through 13 and 19 through 20, characterized by the outer flange (114) is fitted in the vicinity of the surface (142) with longitudinally running catching thumbs (155) of tubular shape with a closed hole at the side of the outer flange (114), the width of which is approximately equal to the width of the recesses (153) in the catching projections (152), and which reach into the recesses (153).

23. Clamping Device as per claims 1 through 13 and 19 through 21 , characterized by there are pressure springs (156) in the catching thumbs 155, which press with the one end against the outer flange (114) and with the other against the partition walls (154) of the catching projections (152) on the ring (128).

24. Clamping Device as per claims 1 through 23, characterized by

the extruded parts (227) touch the recesses (232), whereby an cf angle forms between the two perpendiculars to the symmetrals of the extruded parts (227) and the tangents to the surface of the extruded parts (227) in the contact points on the recesses (232), while a j angle forms between the straight lines running through the contact points and perpendicularly to the cross-sectional plane between the recesses (232).

25. Clamping Device as per claims 1 through 24, characterized by the inner surface (242) of the ring (228) increases in steps, at approximately the level of the outer flange (214), into a ring-shaped projection (282), while the catching thumbs (233) on the ring (288) are fitted in the longitudinal direction with blind holes 283, with a hole on the side of the outer flange (214), in which there are pressure springs (284) also resting against the outer flange (214).

26. Clamping Device as per claims 1 through 25, characterized by the catching thumbs (233) are fitted, at the side of the inner flange (212), with projections (285) of conical shape under a <f angle, reaching into the blind holes (286) on the inner flange (212) with an equal < angle.

27. Clamping Device as per claims 1 through 26,

characterized by the angles S , £ , co are in such interrelation that the ring (228) lies in the direction of upward motion in the area of self-holding, whereby a turn of the ring (228) anti-clockwise is made very easily or automatically.