SI9300225A - Fastening device for rapid tool fastening, especially for disc-like tools - Google Patents

Abstract

Fast axial clamping device is suggested fixing tools, especially flat-shaped tools, e.g. grinding wheels (10) for portable angle grinders screwed to the threaded end (4) of the drive spindles (1), on the outside by facing opposite a standing flange (6) that is invariably connected to drive spindle (1), compress the grinding wheel (10). It consists of two opposite flanges (14, 12) having their teeth facing each other (19,20), with the left screw faces through which it is passed frictional force. In the radial direction, the flanges (14, 12) the projecting thumbs (24, 23) which with their opposite standing planes (39, 38) form as 2 alpha and honey which are the discharge portions (27) which extend in the longitudinal direction touch grooves (32), wedge shaped, with beta angle. The grooves (32) are on the ring (28) which closes in the longitudinal direction space between flanges (14, 12). The ring (28) has positioning thumbs (35) resting on positional ones nuts (37) rigidly connected to the flange (14) and catching thumbs (33). Between the catching thumbs (33) and the spouts the thumbs (24) are pressure springs (34).

Description

TECHNICAL FIELD

According to the International Patent Classification, the invention is classified in class B24B45 / 00 and B24B23 / 02.

TECHNICAL PROBLEM

The proposed solution of the clamping device solves the problem of fast clamping and clamping of tools, in particular flat shapes (eg grinding wheels, circular saw blade) manually, without the use of additional tools and with minimal force.

BACKGROUND OF THE INVENTION

The solution described in DE-OS3644440 is known. In this solution, the tool (grinding wheel) is sandwiched between an outer flange that is screwed to the end of the drive spindle of the angle grinder and an internal flange that transmits torque, but is axially movable and is loaded through the annular part by the axial force of the grinding wheel clamp. The annular part is unrelated to the drive spindle. Both sections have left-leaning sloping surfaces facing each other, whose rising angle lies in the area of self-restraint. The mutual rotation of the inner flange against the annular part is prevented by a special lever mounted in the radial direction, which with one side face rests on the annular part and the other with the locking nose on the inner flange. Moving the lever out of the area of the locking nose releases the mutual rotation of the two parts, and since the friction force between the parts is reduced to a minimum due to the slope, the grinding wheel can be manually rotated together with the inner and outer flange, thus releasing the fixing force, which enables manually unscrewing the outer flange to replace the grinding wheel without the use of additional tools.

The solution described has several disadvantages:

1. The lever that can be used to release the clamping force of the grinding wheel lies on the inside of the tool, where it is difficult to reach.

2. The lever extends radially above the cylindrical surface, which rotates during operation of the machine and, in a particular case, can hit the workpiece, causing a blow to the machine. This can be dangerous for the user.

3. With oblique surfaces, however, friction between the inner flange and the annular part is minimized, but the force of friction between the threads still needs to be overcome for unscrewing the outer flange, which cannot be achieved with heavily tightened outer flange and perhaps even rusty threads. without using additional tools.

DESCRIPTION OF THE NEW SOLUTION

The tools, especially the flat-shaped ones, are fixed to the drive spindles of the machines by the force of friction, which is obtained by squeezing the tool between two flanges located at the end of the drive spindle. The inner flange is inextricably connected to the drive spindle, and the outer flange is screwed to the drive end of the drive spindle so that the axial force of the threaded joint is pressed on the tool and the force is transferred to the inner flange via the tool. The friction force generated between the joint surfaces, flanges and tools, in turn, transmits torque and rotation from the drive shaft to the tool. Influential parameters respectively. the dimensions of the flanges and the drive spindle are chosen so that in no case can the tool slip between the flanges. If the torque on the tool is greatly increased (eg due to a violent locking of the tool), the outer flange is further tightened so that the axial force and thus the friction force between the flange and the tool are increased so that the tool does not slip. . Since such blockages can be very violent in some cases, it is clear that the torque of self-tightening of the outer flange is very large in this case, and given that the threaded surfaces can be corroded, which further complicates the unscrewing of the flange. , in such a case, it is very difficult to unscrew the flange despite the use of additional tools. The proposed clamping device allows the tool to be changed manually, using minimal force and without additional tools. A derivative example of the proposed clamping device will be explained by means of figures supplementing the description of the device.

Pictures show:

Figure 1: Simplified longitudinal section through the clamp device mounted on the drive spindle portable angle grinder. Figure 2: Simplified partial section along line D-D from Figure 1. Figure 3: A simplified partial cross-section along line A-A of Figure 2 developed into a plane. Figure 4: Simplified partial section along line B-B s pictures 2. Figure 5: Simplified partial section along line C-C s pictures 2. Figure 6: Simplified longitudinal section through another example of a clamping device installed on the drive shaft of the transmission angular grinder. Figure 7: Simplified partial section along E-E line from Figure 6.

Figure 1 shows a simplified longitudinal section through the drive spindle (1) of a portable angle grinder, which ends with a screw nozzle (2) whose diameter is smaller than the diameter of the drive spindle (1). The screw nozzle (2) consists of a cylindrical part (3) and a threaded end (4) terminating the drive spindle (1). On the annular surface (5) between the drive spindle (1) and the screw nozzle (2) rests a flange (6), which is non-rotatably coupled to the drive spindle (1). The center hole in the flange (6) contacts the cylindrical part (3) of the screw nozzle (2), thereby centering, in the radial direction, the drive spindle (1). The concentrically centered hole (7) has a flange (6) with an outer centering surface (8) on which a grinding plate (10) is centered over the center of the hole (9). On the opposite side of the flange (6), the proposed clamping device (11) is screwed onto the screw nozzle (2) so that the sanding plate (10) is sandwiched between the flange (6) and the clamping device (11). The clamping device (11) has two flanges (12) and (14), which stand in the axial direction opposite each other. The inner flange (12) which presses against the abrasive plate (10) is relatively flat in shape with a central hole (13) whose diameter is gradually increased to a diameter slightly larger than the diameter of the centering hole (9) on the side of the abrasive disc. grinding wheels (10). The outer flange (14) consists of a relatively flat portion and a central tubular portion (15) extending through a hole (13) of the inner flange (12). At the point where the hole (13) changes diameter, there is a groove (16) in the annular portion (15), into which a clip (17) is inserted, which prevents the flanges from being separated and thus integrates them together.

The outer flange (14) has a central hole in the center with a female thread (18) which engages the outer thread of the screw adapter (2). Both flanges (14) and (12) have teeth (19) and (20) in the axial direction, facing one another or against the inside of the clamping device (11). Teeth (19) or. (20) have a longitudinal cross-section about the shape of a right triangle whose longest side is inclined by the angle y towards the plane perpendicular to the axis of the spindle (1) and since the teeth have a width in the radial direction, the left helical surfaces are formed (21) and (22) forming one surface of the teeth (19) and. (20). A clamping force is transmitted through the screw surfaces (21) and (22) from the outer flange (14), which is screwed on the drive spindle (1), to the inner flange (12), which presses on the grinding plate (10). The abrasive plate (10) rests on a flange (6) which rests on the drive spindle (1) through the annular surface (5), where the clamping force is intercepted.

Both flanges (12) and (14) have projecting extending thumbs (23) and (24) in the radial direction. The projecting thumbs (23) are connected in the longitudinal direction to the inner flange (12) and extend radially from the outer circumference (25) and the teeth (20) outwards. The projecting thumbs (24) are connected in the longitudinal direction to the outer flange (14) and extend radially from the outer circumference (26) and the teeth (19) outwards. Between the pivoting thumbs (23) and (24), there are dislodged sections (27) having a roller shape or a wedge-shaped shape with a semicircular end on the thicker side. The bending parts (27) touch the bending thumbs (23) and (24) on the surfaces (38) and (39), which are facing one another in a rotational direction.

Between the two flanges (12) and (14) extends in the longitudinal direction a ring-shaped portion (28), with reduced wall thickness at both ends. Through the resulting annular surfaces (29) or. (30) reach the circumference (43) or. (42) flanges (12) respectively. (14) and preventing the ring (28) from falling in the longitudinal direction. The outer circumference (41) of the ring (28) is ribbed, thereby facilitating manual tightening and unscrewing of the clamping device (11). The inner surface (31) of the ring (28) has longitudinal grooves (32) extending approximately tangentially to the inner surface (31). The longitudinal grooves (32) are supported by the projection portions (27) which cannot be displaced radially outwards. In the radial direction, the ring (28) has relatively narrow catching thumbs (33) extending in the radial direction approximately to the outer circumference (25) or. (26), tooth (19) or. (20). There are pressure springs (34) between the catching thumbs (33) and the challenge thumbs (24). Slightly forward clockwise (arrow 44), the ring (28) has radially positioned thumbs (35) that are slightly shorter than the catching thumbs (33) in the radial direction. The thumbs (33) and (35) extend in a longitudinal direction to the unscrewing nozzles (36) which are fixedly connected to the outer flange (14). The positioning thumbs (35) rest in a rotational direction on the positioning pins (37), which are also fixedly connected to the outer flange (14). The relative position of the grooves (32) against the positioning thumbs (35) and the positioning of the positional mountings (37) against the challenge thumbs (24) are determined so that between the common tangents passing through the touch points on the challenging parts (27) and. The grooves (32) and the perpendiculars to the symmeters, which run radially through the center of the challenging rollers (27), establish an angle β that is slightly smaller than the slip angle (as a slip angle). The relative position and the shape of the contact surfaces (38) and (39) on the challenge, thumbs (23) and (24) and the position of the grooves (32) are determined such that tangents to the circumference of the challenge parts (27) passing through the common contact points for the challenging parts (27) and surfaces (38) and (39) on the challenging thumbs (23) and. (24) form the angle 2a

The angle a is a little larger than the angle of self-slip. The contact surfaces (38) and (39) are designed in such a way that the angle 2a is maintained even with a smaller rotation of the flanges (12) and (14). However, the relative position of the projecting thumbs (24) against the position of the teeth (19) and the projecting thumbs (23) against the position of the teeth (20) are determined such that the teeth (19) and (20) are spaced slightly in the rotational direction.

It goes without saying that seals have been installed on all the slots where moisture and dust could penetrate the inside of the clamping device (11).

The outer position of the outer ring (28) against the flanges (12) and (14) is maintained by springs (24) that move the ring (28) in a rotational direction until the positioning thumbs (35) are in contact with the positioning lugs (37).

When the clamping device (11) is screwed clockwise (arrow 44) onto the drive spindle (1), the torque is transmitted to the outer flange (14) via the teeth (19) via the teeth (19). ) and (20), the torque is also transferred to the inner flange (12). When the inner flange (12) with its outer surface (40) is applied to the abrasive plate (10), an axial force appears on it, which is transmitted to the outer flange (14) through the screw surfaces (22) and (21). through the internal threads (18) to the threaded plug (2) or. drive spindle (1). Also, the axial force appears on the flange (6), which is also transmitted through the surface (5) to the drive spindle (1). The axial force transmitted through the screw surfaces (21) and (22) causes, because the angle of rise y of these surfaces in the self-slip region, the teeth (19) try to slide along the screw surfaces (21) and (22) and thereby rotate outer flange (14) anticlockwise (arrow 45). This rotation is prevented by the bending parts (27), which are supported by the bending thumbs (24) and (23). Since the projection fingers (24) and (23) with their contact surfaces (39) and (38) form wedge spaces with an angle of 2 a and because the angle a is larger than the angle of self-slip, the projection parts (27) tend to move radially outwards. This displacement prevents the ring (28) with its grooves (32) supported by the projecting parts (27). Between the perpendiculars to the radial symmeters of the offset parts (27) and the common tangents, at the touch points of the offset parts (27) and the grooves (32), otherwise β is smaller than the self-slip angle, which does not lead to self-slip of the offset parts (27 ) along the grooves (32) and thereby slip the teeth (19) along the screw surfaces (21) and (22).

To replace the grinding wheel (10) it is necessary to rotate the ring (28) slightly anti-clockwise (arrow 45). The sliding parts (27) thus slide along the grooves (32). As the grooves (32) are wedge-shaped, the projecting parts (27), while sliding along the grooves (32), also move radially outwards. This releases the movement of the flanges (14) and (12) in the direction of rotation. The teeth (19) slide along the screw surfaces (21) or. (22), thus turning the flange (14) slightly anticlockwise (arrow 45). This releases the axial force between the inner threads (18), the flange (14), and the outer threads of the threaded part (4), thus also eliminating the friction force between them, as well as the friction force between the inner flange (12) and the abrasion. the plate (10), and the fixing device (11) can be easily unscrewed, manually unscrewed and replaced by the sanding plate (10).

Figure 6 shows another embodiment of a clamping device (111). For the parts corresponding to the first embodiment, they are used for 100 larger indications, in order to reduce the repetition of the description of the first embodiment.

The second example of the clamping device (111) shown in Figures 6 and 7 differs from the first in that the axial pressure release is achieved by moving the ring (128) in the longitudinal direction outward (arrow 151). For better grip of the ring (128) by hand, it has an annular nozzle (157) approximately at the height of the outer flange (114). Moving the ring (128) outwards is more favorable, e.g. for fastening grinding discs (110) having a clamping surface deep and making the circumference (141) of the ring (128) difficult. Such a direction of release of axial pressure is achieved by the fact that the inner circumference (132) of the ring (128) is shaped approximately like a sheath of a truncated cone, with a wider part on the side of the abrasive plate (110) and with an angle β toward the axis of the cone. The inner circumference (132) of the ring (128) is also adapted to the shape of the projecting parts (127), which are in this case made in the form of beads or wedge-shaped with a semicircular end on the wider side. The ring (128) has in its longitudinal direction the catch nozzles (152) extending between the flanges (114) and (112). The catch nozzles (152) have grooves (153) in the longitudinal direction, terminating on the side of the inner flange (112) with partition walls (154). In the grooves (153) extend in the longitudinal direction the catching thumbs (155), tubular shaped with a closed hole on the side of the flange (114), whose diameter is approximately equal to the width of the grooves (153), and which are rigidly connected to the outer flange (114). Thus, the ring (128) and the outer flange (114) are fixed in a rotational direction. The thumb catcher (155) has compression springs (156) that press one end to the outer flange (114) and the other side to the partition walls (154) that rest on the inner flange (112). The spring force is intercepted at the clamp (117).

To replace the grinding wheel (110), it is necessary to move the ring (128) slightly outwards (arrow 151). This releases the movement of the bending parts (127) in the radial direction outwards, thereby rotating the flange (114) against the flange (112) and thereby releasing the axial or. fixing forces.

The advantages of the clamping device described (11,111) lie in the reliable operation and the very small force required to replace the grinding wheel (10,110). It is known that when using angle grinders outdoors or in damp areas, threaded surfaces (18) may become rusty, thereby greatly increasing the friction force between the threads. Thus, despite the relaxation of the movement of the flanges (14,114) and (12,112) in the direction of rotation, at a relatively small angle γ, the screw surfaces (21) and. (22), there is no slip along these surfaces and the clamping device (11,111) cannot be unscrewed without the use of additional tools. In contrast, increasing the angle y increases the force required to rotate or. displacement of the ring (28,128) and thus release of movement of the flanges (14,114) or. (12,112). The described solution of the clamping device (11,111) allows, despite the relatively large angle y, to rotate or to rotate. displacement of the ring (28,128) with minimum force. This is achieved by the fact that the angle a is only slightly larger than the self-slip angle, while β is only slightly smaller than the self-slip angle. Since the angle a is relatively small, the force that pushes the bending parts (27,127) radially outwards is relatively small, and because, in the case of rotation and / or rotation, the displacement of the ring (28,128) actually slides along the slope with an angle β downwards, and since the angle β is only slightly smaller than the angle of self-slip, it is clear that the force required to rotate or rotate it is. the displacement of the ring (28,128), despite its relatively large angle y, is very small and can be achieved manually. If for certain reasons, such as severe damage or even breakage of threads (18) or. threads on the threaded part (4), despite the relaxation, there is no twist of the flange (14), due to the relatively large angle y, the teeth (20) slide along the screw surfaces (21) or. (22), thus slightly rotating the flange (12,112) clockwise (arrow 44), thus also releasing axial pressure between the threads (18) and the threads on the threaded part (4). If the damage to the threads (18) or the clamping device (11,111) is so large that it does not rotate the flanges (14,114) or (12,112) despite the release, the ring (28) must be rotated counterclockwise (arrow 45 ) until the positioning fingers (35) engage the unscrewing nozzles (36) and forcibly unscrew the ring (28), outer flange (14) or clamping device (11). Since the clamping device (111) has a ring (128) in a rotational direction, rigidly connected to the flange (114), by rotating the ring (128) it is also forced to unscrew the clamping device (111).

A further advantage of the clamping device described (11,111) is that it is very low and thus does not disturb the users of the angle grinder at work. Also, the clamping device (11,111) has very few components and is therefore inexpensive.

Claims (22)

PATENT APPLICATIONS 1. A clamping device (11,111) for fast axial fastening of a tool, especially a flat shape, e.g. grinding discs (10,110) and circular saw blades screwed to the threaded end (4) of the drive spindle (1) by squeezing the grinding disc (6), which is pivotally connected to the drive spindle (1) (10,110), characterized in that it is longitudinally opposite the inner flange (12,112), which, with its outer surface (40), presses against the abrasive plate (10,110) and which is of relatively flat shape with a central hole (13) whose diameter is slightly enlarged on the side of the grinding wheel (10,110), the outer flange (14,114), which is also relatively flat in shape with a central attachment (15), a tubular shape extending through the hole (13) of the inner flange (12,112) where the diameter of the hole (13) increases, a groove (16) in which there is a hinge (17,117) and on the inner circumference there is a thread (18) by which the outer flange (14,114) is screwed to the threaded end (4) of the drive spindles (1). Clamping device (11,111) according to claim (1), characterized in that the inner flange (12,112) is pivotally connected to the central attachment (15) and, partly relative to the outer flange (14,114), partly movable in the longitudinal direction . Clamping device (11,111), according to claims 1 and 2, characterized in that the inner flange (12,112) and the outer flange (14,114) have a rotary part of the surface facing the inside of the clamping device (11,111). teeth facing one another (19) or. (20), approximately saw-shaped. Clamping device (11,111), according to claims 1 to 3, characterized in that the surfaces (21) or. (22) tooth (19) respectively. (20), which in the axial direction lie opposite to each other, portions of left helical surfaces, with angle of inclination? Clamping device (11,111), according to claim 4, characterized in that it lies in an inclination angle γ deep in the self-sliding region. Clamping device (11,111), according to claims 1 to 5, characterized in that the teeth (19) or. (20), in the radial direction, are bounded by the circumference (26) or. (25), which are about the same diameter, and from these circumferences, in the radial outward direction, extend relatively narrow projecting thumbs (24) or. (23), distributed in a rotational direction, terminating in the radial direction slightly in front of the outer circumference (42) or. (43), flanges (14,114) respectively. (12,112), and in the longitudinal direction they reach approximately the height of the teeth (19) or. (20). Clamping device (11,111), according to claims 1 to 6, characterized in that the relative position of the inner flange (12,112) against the outer flange (14,114) is in a rotational direction such that the projecting thumbs (23 ) and (24) pairs, in a rotational direction relatively close, and between them are the protruding parts (27,127), which touch the surfaces (39) or. (38), which are on the projecting thumbs (24) or. (23) and, in a rotational direction, lie one opposite to the other, Clamping device (11), according to claim Ί, characterized in that the projecting parts (27) have a roller shape or a wedge-shaped shape with a semicircular end on a wider part. Clamping device (111) according to claim 7, characterized in that the projecting parts (127) have a ball-shaped or wedge-shaped shape with approximately a semicircular end on a wider part. Clamping device (11,111), according to claims 1 to 9, characterized in that the common tangents to the perimeter of the projecting parts (27, 127) and the surface (39) or. (38), at common touch points, form an angle of 2 a and that the surfaces (39) and (38) adjacent to these touch points are designed so that the angle 2 a does not change, despite the smaller inter-turn of the flanges (14,114) and (12,112) and the associated displacement of the displacement inches (23) and (24) in the rotational direction. Clamping device (11,111) according to claim 10, characterized in that the angle a is slightly larger than the self-slip angle. Clamping device (11,111), according to claims 1 to 11, characterized in that the reciprocal position of the projecting thumbs (24) is against the teeth (19) in a rotational direction and the projecting thumbs (23) against the teeth (20). ), in the same direction such that the teeth (19) and (20) are slightly spaced in the rotational direction. Clamping device (11) according to Claims 1 to 12, characterized in that, through both circumference (42) and (43), flanges (14) or. (12) extends the ring (28), with the ribbed outer circumference (41), which is pivotally connected to the flanges (12) and (14) and partially displaced in the longitudinal direction, with its inner circumference (31) extending at both ends. increases stepwise, over the resulting annular surfaces (29) or. (30) and the flanges (12) and. (14). Clamping device (11) according to claim 13, characterized in that the ring (28) has rotationally arranged longitudinal grooves (32) having a wedge-shaped cross-section in the inner circumference (31). , extending clockwise (arrow 44), at a certain distance from them, in the same direction, but relatively narrow, radially inwards, running, the catching thumbs (33) terminating in a radial direction slightly before the circumference ( 25) respectively. (26) tooth (19) or. (20), and a little further, in the same direction, in the shape of a similar, slightly shorter, positional thumb (35). Clamping device (11), according to claims 1 to 14, characterized in that there are pressure springs (34) between the spout fingers (24) and the catch sticks (33). Clamping device (11) according to Claims 1 to 15, characterized in that the outer flange (14), in the longitudinal direction of the circumference (42), has positional lugs (37) which are provided with they are fixedly connected and supported by the positioning thumbs (35), and between the catching thumbs (33) and the positioning thumbs (35) extend, in the longitudinal direction, to the unscrewing nozzles (36), which are also fixedly connected to the outer flange (14). ). Clamping device (11), according to Claims 1 to 16, characterized in that the bending parts (27) touch the grooves (32), the ring (28) in the longitudinal direction, and that between the rectangles there are bending parts (27) and tangents to the periphery of the bending parts (27), at tangent points at the grooves (32), such as β Clamping device (111) according to Claims 1 to 12, characterized in that, through both the circumference (142) and (143) of the flanges (114) or. (112) extends a ring (128), with a stepped step extending about the height of the outer flange (114) into the annular nozzle (157), which is partly moved in a longitudinal direction, the inner circumference thereof (132) is approximately the shape of a truncated cone, with a larger diameter on the side of the inner flange (112), inclined by an angle β toward the cone axis, and whose diameter increases stepped over both ends via the annular surfaces thus formed (129) or . (130) and the flanges (112) and. (114). 19. The clamping device (11,111) according to claims 17 and 18, characterized in that the angle β is slightly smaller than the self-slip angle. 20. The clamping device (111) according to claim 18, characterized in that the ring (128) has, in the longitudinal direction, trailing nozzles (152) extending between the flanges (112) at the inner circumference (132). and (114), with longitudinal grooves (153) terminating at the inner flange side (112) with partition walls (154). Clamping device (111), according to claims 1 to 12 and 18 to 20, characterized in that the outer flange (114), adjacent to the circumference (142), extends longitudinally, the catching thumbs (155), tubular in shape, with a closed hole on the side of the outer flange (114), the width of which is approximately equal to the width of the grooves (153), in the catch nozzles (152), and extending into the grooves (153). Clamping device (111), according to claims 1 to 12 and 18 to 21, characterized in that there are pressure springs (155) in the catching thumbs (155), which press one end onto the outer flange (114) and the other end to the partition walls (154) of the catching nozzles (152), on the ring (128).