EP1404490B1 - Attachment for grinder - Google Patents

Description

State of the art

The invention relates to an insert tool according to the preamble of claim 1 such as in the US-A-2789402 disclosed.

Application tools are known for grinding machines, which have an abrasive sheet and a rubber backing pad as a support for the abrasive sheet. The support plate and the abrasive sheet are fitted with their hubs, each having a central, substantially circular recess on a drive shaft, at the free end of a thread is formed. With a nut screwed onto the thread, the sanding sheet can be tensioned against the backing pad and the backing pad against a flange connected to the drive shaft. In the assembled state results in the axial direction a positive engagement and in the circumferential direction a frictional connection between the abrasive sheet, the backing pad and the flange.

From the US 2,789,402A an insert tool with an abrasive sheet, a backing pad and a hub is known, wherein the hub formed by a separate from the backing pad component is. An element movably mounted against a spring can be operatively connected to a driving device of the grinding machine.

Advantages of the invention

The invention relates to an insert tool with an abrasive sheet and a support plate and with a hub having at least one recess, via which the hub can be tensioned on a driving flange of a grinding machine connected to a drive shaft.

It is proposed that the hub is formed by a separate component from the support plate. It can be achieved a particularly inexpensive and well stackable insert tool whose hub can be easily designed for a conventional entrainment device of a grinding machine with a nut and / or for a quick-release system.

In an advantageous embodiment of the invention, the insert tool via at least one movable against a spring element latching element with a driving device of the grinding machine is operatively connected, which engages in an operating position of the insert tool and fixes the insert tool positively. By the positive locking a high security can be achieved, and it can be created a simple and inexpensive tool-free quick-release system. Unintended running of the insert tool can be safely avoided, even with braked drive shafts in which large braking torques can occur.

By the movably mounted locking element, a large deflection of the locking element can be made possible during assembly of the insert tool, whereby on the one hand, a large overlap between two corresponding locking elements and a particularly secure positive engagement can be realized and on the other good audible Einrastgeräusch can be achieved, which advantageously signals an operator a desired snap action performed.

The locking element can fix the insert tool directly or indirectly via an additional component form-fitting manner, for example via a locking element coupled to the rotatable and / or axially displaceable locking lever or plunger, etc. The locking element, the insert tool in different directions directly and / or indirectly positively fix, such as in the radial direction, in the axial direction and / or particularly advantageous in the circumferential direction. It is also possible that the insert tool is fixed positively in a second direction by the positive locking of the insert tool with the locking element in a first direction, for example in the radial direction, the insert by a separate component from the locking element in a second direction, for example in the circumferential direction.

Is in the hub at least a first recess for a positive connection with the driving device in at least one circumferential direction and at least one second recess separated from the first recess for a positive connection in the axial direction introduced, simple and inexpensive hubs can be achieved, which substantially advantageous can be executed just and without hooks. Hooking of the hubs during manufacture and storage can be avoided and good handling of the insert tool with its hubs can be made possible. Further, the components for securing the hub can be advantageously designed for their function, ie either on the fixation in the circumferential direction or on the fixation in the axial direction.

The hubs can easily be carried out advantageously with a closed center hole and it can be a low-vibration running of the insert tool allows. Furthermore, it can be achieved with a suitable choice of the diameter of the center hole, that the insert tools according to the invention can be attached via previously known fastening devices on conventional grinding machines, in particular via fastening devices, in which the insert tool with a clamping nut and a clamping flange on the drive shaft against a support surface positively in the axial direction and non-positively fixed in the circumferential direction.

In a further embodiment of the invention it is proposed that at least one elongated hole is introduced into the hub, which has a wide area and at least a narrow area. The hub can be easily stretched over the slot in the axial direction. The hub can be used as a spring element, for example, by the hub is elastically deformed when moving the component in the slot. In addition, the hub can be used to deflect a component against a spring element in the axial direction. Additional components, assembly costs and costs can be saved.

It is also proposed that the hub has a deviating from the rotational symmetry contour, in particular outer contour, which is positively connected in the circumferential direction with a corresponding contour, in particular the inner contour of the support plate. A torque can be transmitted from the hub advantageous by a positive connection to the support plate. Additional fasteners, for example to achieve a frictional connection, can be avoided or at least supported in their function and costs can be saved. The hub can be mounted directly on the driving flange, whereby a particularly accurate positioning of the hub, the sanding sheet and the support plate to each other can be achieved. Furthermore, the hub can be accessed and fastened with short locking elements. The hub may have various contours appearing reasonable to those skilled in the art for transmitting the torque by positive engagement, such as an oval or polygonal contour, etc., which may be formed in various areas of the hub.

In a further embodiment of the invention it is proposed that the deviating from the rotational symmetry contour is formed on a pointing in the axial direction shaping of the hub, whereby a large transfer surface between the hub and the support plate and thus at a torque transmission over the transfer surface an advantageously small surface pressure can be achieved.

If the molding has inclined side walls, the hub can be stacked particularly advantageously and centering of the hub in the support plate can be achieved.

The hub may be formed of various materials that appear appropriate to those skilled in the art, for example, a high-strength plastic, etc. Advantageously, however, the hub is formed by a deep-drawn sheet metal part, which is particularly inexpensive and easy to produce.

Lie in the assembled state in the axial direction of the grinding machine, a bearing surface of the hub and a support surface the support plate in a common plane, a corresponding bearing surface of a flange can be shared and a common reference plane can be achieved for the support plate and the hub. Additional components can be saved and it can be advantageously achieved an exact assignment of the support plate and the hub to each other.

In a further embodiment of the invention, it is proposed that the hub is formed by a separate component from the abrasive sheet, whereby the sheet metal hub can be stored to save space, inexpensive to produce and in particular easy to reuse.

If the hub has a contour deviating from the rotational symmetry in the region of its abutment on the abrasive sheet, which can be positively connected in the peripheral direction with a corresponding contour of the abrasive sheet, a torque can advantageously be transmitted in a form-fitting manner via the contours. Additional fasteners for transmitting torque from the hub to the abrasive sheet may be functionally supported or possibly completely replaced. In principle, however, the hub can be connected to the sanding sheet via all frictional, positive and / or material-locking connections that appear appropriate to the person skilled in the art, for example via an adhesive connection, rivet connection, clamping connection, etc.

If the hub has claws that can be inserted into the sanding sheet, the hub can be simply, safely and without tools connected to the sanding sheet. With a small axial force between the hub and the abrasive sheet large holding forces in the circumferential direction can be achieved. The axial force can advantageously be generated by the assembly process of the insert tool on the grinding machine.

The claws may be formed by additional components attached to the hub. Advantageously, however, the claws are integrally formed on the hub, for example in a punching operation. The production of the claws can thereby be advantageously incorporated into the manufacturing process of the hub and additional components can be avoided.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown.

Fig. 1

einen Winkelschleifer von oben,

Fig. 2

einen schematischen Querschnitt entlang der Linie II-II in Fig. 1,

Fig. 3

ein Einsatzwerkzeug aus Fig. 1 und 2 von unten,

Fig. 4

ein zu dem Einsatzwerkzeug aus Fig. 2 alternatives Einsatzwerkzeug,

Fig. 5

einen vergrößerten Ausschnitt V aus Fig. 4 und

Fig. 6

das Einsatzwerkzeug aus Fig. 4 von unten.

Show it:

Fig. 1

an angle grinder from above,

Fig. 2

a schematic cross section along the line II-II in Fig. 1,

Fig. 3

an insert tool from FIGS. 1 and 2 from below,

Fig. 4

a deployment tool alternative to the deployment tool of FIG. 2,

Fig. 5

an enlarged section V of Fig. 4 and

Fig. 6

the insert tool of FIG. 4 from below.

Fig. 1 shows an angle grinder 30 from above with a mounted in a housing 54, not shown electric motor. The angle grinding machine 30 can be guided via a first, in the housing 54 on the side facing away from an insert tool, extending in the longitudinal direction of the handle 56 and a second, attached to a gear housing 58 in the region of the insert tool, extending transversely to the longitudinal direction handle 60.

With the electric motor, a drive shaft 62 can be driven via a transmission not shown in detail, at whose end facing the insert tool a driving device 36 is arranged (FIG. 2). The entrainment device 36 has on a side facing the insertion tool on the drive shaft 62 firmly pressed driving flange 28 and on a side facing away from the application tool on the drive shaft 62 axially against a centrally disposed helical spring 32 slidably mounted drive plate 64. On a support surface 68 for the Insert tool forming driving flange 28 is a collar 70 formed over which the insert tool is centered radially with its center hole 26 in the mounted state. Radial forces can be advantageously absorbed by the driving flange 28.

In the driving flange 28 are arranged in the circumferential direction 38, 40 in a row uniformly arranged in the axial direction 42 to the insert tool on the driving flange 28 and over the support surface 68 extending pins 66 for axial fixing of the insert tool in the axial direction 42 against each plate spring 74 are slidably mounted.

The pins 66 have at their end facing the insert tool each having a head which has a larger diameter than a remaining part of the pin 66 and on a driving flange 28 side facing a conical, in the axial direction 72 tapered contact surface 76 and a parallel to the support surface 68 extending contact surface 78 has.

In the driving flange 28 three axial through-holes 80 are in the circumferential direction 38, 40 inserted one behind the other, namely, in each case a through hole 80 in the circumferential direction 38, 40 between two pins 66 is arranged.

In the axially displaceably mounted on the drive shaft 62 drive plate 64 three bolts 34 are pressed one behind the other in the circumferential direction 38, 40, which extend in the axial direction 42 to the insert tool on the drive plate 64. The drive plate 64 is pressed by the coil spring 32 in the direction 42 to the insert tool against the driving flange 28. The bolts 34 project through the through holes 80 and extend in the axial direction 42 via the driving flange 28th

The unlocking button 82 has three in the circumferential direction 38, 40 evenly distributed, in the axial direction 72 to the axially movable drive plate 64 extending segments 84 which pass through corresponding recesses 86 of the driving flange 28 engage and a snap ring 88 with the drive plate 64 in the axial direction 42, 72 are firmly connected. The unlocking button 82 is in an annular recess 90 in the driving flange 28 in the axial direction 42, 72 slidably guided.

The insert tool has an abrasive sheet 10, a backing pad 14 made of rubber and a deep-drawn sheet metal hub 18 which is formed by a separate from the backing pad 14 component. The sheet metal hub 18 is pressed at its outer periphery with the abrasive sheet 10 and fixedly connected by rivets 92 (FIGS. 2 and 3).

The sheet metal hub 18 has a recess 94 pointing in the axial direction to the angle grinder 30 with inclined side walls 104 (FIG. 2). The formation 94 has an outer contour deviating from the rotational symmetry in the form of a triangle with rounded sides (FIG. 3). The outer contour of the formation 94 corresponds to an inner contour of the annular support plate 14, so that the sheet metal hub 18 with its outer contour in the circumferential direction 38, 40 positively in the support plate 14 can be inserted and a torque from the sheet metal hub 18 form-fitting transferable to the support plate 14 during operation.

When mounting the insert tool, the support plate 14 is placed on the support surface 68 of the driving flange 28, wherein the support plate 14 comes in three evenly distributed over the circumference edge regions 96, 98, 100 of the support surface 68 of the driving flange 28 comes to rest. The round support surface 68 of the driving flange 28 covers the inner contour of the support plate 14 on the side facing the driving device 36, which is designed according to the outer contour of the molding 94 in the form of a triangle with rounded sides, respectively in the central region of the pages. Subsequently, the sheet metal hub 18 is inserted with its shape 94 in the support plate 14 and centered. The sheet metal hub 18 and the support plate 14 are then connected to the driving device 36.

The sheet metal hub 18 has to circumferentially 38, 40 consecutively three evenly spaced holes 22, the diameter of which is slightly larger than the diameter of the bolt 34. Further, the sheet metal hub has three evenly distributed in the circumferential direction 38, 40, extending in the circumferential direction 38, 40 Long holes 24, each having a narrow portion 46 and a wide, made by a bore portion 44 whose diameter is slightly larger than the diameter of the heads of the pins 66th

In the sheet metal hub 18, the centering hole 26 is further introduced, the diameter is advantageously chosen so that the insert tool can be clamped with a conventional clamping system with a clamping flange and a spindle nut on a conventional angle grinder. It ensures a so-called backward compatibility.

When mounting the insert tool, the sheet metal hub 18 is pushed with its center hole 26 on the release button 82 and radially centered. Subsequently, the abrasive sheet 10, the sheet metal hub 18 and the form fit to the support plate 14 and the latter, ie the entire insert tool is rotated until the pins 66 engage in the designated wide areas 44 of the slots 24 of the sheet metal hub 18. Pressing the sheet metal hub 18 against the bearing surface 68 of the driving flange 28 causes the bolts 34 in the through holes 80 and the driving plate 64 against a spring force of the coil spring 32 the drive shaft 62 are axially displaced in the direction away from the insert tool 72 direction.

Further rotation of the sheet metal hub 18 against the drive direction 40 causes the pins 66 are moved into the arcuate narrow portions 46 of the slots 24. The pins 66 are displaced axially over the conical bearing surfaces 76 against the pressure of the disc springs 74 in the direction 42 until the contact surfaces 78 of the pins 66 cover the edges of the elongated holes 24 in the arcuate narrow regions 46. The plate springs 74 press on the contact surfaces 78 of the pins 66, the insert tool or the sheet metal hub 18 with its support surface 48 and the sheet metal hub 18 which engages over the support plate 14, the support plate 14 with its support surface 50 to the support surface 68 of the driving flange 28. Die Support surface 48 of the sheet metal hub 18 and the support surface 50 of the support plate 14 come to rest in the axial direction 72 to the angle grinder 30 in a common plane, in a plane determined by the support surface 68 of the driving flange 28 level.

Instead of having a plurality of disc springs 74, the pins 66 may also be loaded via a common spring element, for example via a plate spring which extends over the entire circumference and which is not shown in detail.

In an end position or in an reached operating position of the insert tool, the bores 22 come to rest in the sheet metal hub 18 via the through holes 80 of the driving flange 28. The bolts 34 are moved by the spring force of the coil spring 32 axially in the direction 42 of the insert tool, engage in the holes 22 of the sheet metal hub 18 and fix them in both circumferential directions 38, 40 positively. When snapping into place, an audible click sound is heard by an operator, signaling that the device is ready for operation.

A drive torque of the electric motor of the angle grinder 30 can positively or positively from the drive shaft 62 on the driving flange 28 and the driving flange 28 via the bolts 34 on the sheet metal hub 18 and the sheet metal hub 18 positively over the deviating from the rotational symmetry contours on the support plate 14 and be transferred to the abrasive sheet 10 via the rivets 92.

An occurring during and after switching off the electric motor, the drive torque opposing braking torque can be positively transmitted from driving flange 28 via the bolt 34 on the insert tool. An unwanted release of the insert tool is safely avoided. By uniformly distributed in the circumferential direction 38, 40 three bolts 34 an advantageous uniform forces and mass distribution is achieved.

To release the insert tool from the angle grinder 30, the release button 82 is pressed. The drive plate 64 is thereby displaced with the bolts 34 via the unlocking button 82 against the coil spring 32 in the axial direction 72 facing away from the insert tool, whereby the bolts 34 move in the axial direction 72 from its locking position or from the holes 22 of the sheet metal hub 18 , Subsequently, the insert tool is rotated in the drive direction 40, namely until the pins 66 come to rest in the wide areas 44 of the slots 24 and the insert tool in the axial direction 42 can be removed from the driving flange 28. After releasing the release button 82, the drive plate 64, the bolt 34 and the release button 82 are moved by the coil spring 32 back to their original positions.

In Fig. 4, 5 and 6, an alternative insert tool is shown. Substantially identical components are basically numbered with the same reference numerals. Furthermore, reference can be made to the description of the embodiment in FIGS. 1 to 4 with respect to the same features and functions. The following description is essentially limited to the differences from the exemplary embodiment in FIGS. 1 to 4.

The insert tool has a sheet metal hub 20, an abrasive sheet 12 and a backing pad 16 made of rubber, wherein the sheet metal hub 20 is formed by a separate from the backing pad 16 and the abrasive sheet 12 component.

The sheet metal hub 20 has a formation 94 pointing in the axial direction to the angle grinding machine 30. The formation 94 forms an abutment with the abrasive sheet 12 and with the backing plate 16 and has an outer contour deviating from the rotational symmetry in the form of a triangle with rounded sides (FIG. 6). The outer contour of the molding 94 corresponds to an inner contour of the annular support plate 16 and an inner contour of the sanding sheet 12, so that the sheet metal hub 20 with its outer contour in the circumferential direction 38, 40 positively in the sanding sheet 12 and in the support plate 16 can be inserted and in operation a torque of the Sheet metal hub 20 positively on the sanding sheet 12 and the support plate 16 is transferable.

An additional torque transmission between the sheet metal hub 20 and the abrasive sheet 12 via formed on the sheet metal hub 20 claws 52, which dig when attaching the insert tool on the angle grinder 30 in the sanding sheet 12. The claws 52 are formed by breakthrough edges 102 which are bent on the side facing the sanding sheet 12 (FIG. 5).

reference numeral

10

sanding sheet

12

sanding sheet

14

backing pad

16

backing pad

18

hub

20

hub

22

recess

24

recess

26

recess

28

driving flange

30

grinding machine

32

spring element

34

locking element

36

driving device

38

circumferentially

40

circumferentially

42

direction

44

Area

46

Area

48

bearing surface

50

bearing surface

52

claw

54

casing

56

handle

58

gearbox

60

handle

62

drive shaft

64

driver disc

66

pen

68

bearing surface

70

Federation

72

direction

74

Belleville spring

76

contact surface

78

contact surface

80

Through Hole

82

release

84

segment

86

recess

88

snap ring

90

recess

92

rivet

94

formation

96

border area

98

border area

100

border area

102

Breakthrough edge

104

Side wall

Claims (11)

1. Application tool having an abrasive disc (10, 12) and a backing pad (14, 16) and having a hub (18, 20) which has at least one aperture (22, 24, 26), via which the hub (18, 20) can be clamped onto a driving flange (28), connected to a drive shaft (62), of a grinder (30), the hub (18, 20) being formed by a component separate from the backing pad (14, 16), characterized in that the hub (18, 20) can be operatively connected to a driving device (36) of the grinder (30) via at least one latching element (34) which is mounted so as to be movable against a spring element (32) and which latches in place in an operating position of the hub (18, 20) and fixes the hub (18, 20) in a positive-locking manner in the circumferential direction.
2. Application tool according to Claim 1, characterized in that at least one first aperture (22) for a positive-locking connection to the driving device (36) in at least one circumferential direction (38, 40) and at least one second aperture (24) separate from the first aperture (22) and intended for a positive-locking connection in the axial direction (42) are incorporated in the hub (18, 20).
3. Application tool according to Claim 2, characterized in that at least one elongated hole (24) is incorporated in the hub (18, 20), said elongated hole (24) having a wide region (44) and at least one narrow region (46).
4. Application tool according to one of the preceding claims, characterized in that the hub (18, 20) has a contour which deviates from the rotational symmetry and can be connected to a corresponding contour of the backing pad (14, 16) in a positive-locking manner in the circumferential direction (38, 40).
5. Application tool according to Claim 4, characterized in that the contour deviating from the rotational symmetry is integrally formed on a shaped portion (94), pointing in the axial direction, of the hub (18, 20).
6. Application tool according to Claim 5, characterized in that the shaped portion (94) has inclined side walls (104).
7. Application tool according to one of the preceding claims, characterized in that the hub (18, 20) is a deep-drawn sheet-metal part.
8. Application tool according to one of the preceding claims, characterized in that, in the fitted state, in the axial direction (72) relative to the grinder (30), a bearing surface (48) of the hub (18, 20) and a bearing surface (50) of the backing pad (14, 16) lie in a common plane.
9. Application tool according to one of the preceding claims, characterized in that the hub (20) is formed by a component separate from the abrasive disc (12).
10. Application tool according to one of the preceding claims, characterized in that the hub (20), in the region in which it bears against the abrasive disc (12), has a contour which deviates from the rotational symmetry and can be connected to a corresponding contour of the abrasive disc (12) in a positive-locking manner in the circumferential direction (38, 40).
11. Application tool according to one of the preceding claims, characterized in that the hub (20) has claws (52) that can dig into the abrasive disc (12).

Images