Electrical tool

Abstract

The invention relates to an electric tool (1), in particular an angle grinder (2), with a drive motor (4) housed in a housing (3) which drives a rotor shaft (5), with a tool spindle (7) having a tool holder (8) which is connected to the rotor shaft (5) by an angle gear (6) which is housed in a gear head (9), with a bearing plate (10) having a spindle passage (11) in which the tool spindle (7) is rotatably mounted, wherein the bearing plate (10) has a mounting flange (12) on which a protective hood (13) can be rotatably mounted, the removal of which from the mounting flange (12) is at least made more difficult by a locking device (21).The locking device (21) is selected from a group comprising at least one locking pin (20) received in the receiving flange (12), a locking ring (27) preferably secured to the receiving flange (12) by a snap-fit ​​connection or by a press-fit connection, a locking plate (33) screwed to the bearing plate (10) by several locking screws (34), a locking clip (44) attached to the bearing plate (10) and a locking tab (50) formed on the protective hood (13).

Description

[0001] The invention relates to an electric tool, in particular an angle grinder, with a drive motor housed in a casing which drives a rotor shaft, with a tool spindle having a tool holder which is connected to the rotor shaft by an angle gear which is housed in a gear head, with a bearing plate having a spindle passage in which the tool spindle is rotatably mounted, wherein the bearing plate has a mounting flange on which a protective hood can be rotatably mounted, the removal of which from the mounting flange is at least made more difficult by a locking device.

[0002] For mounting the protective cover to the bearing plate, a keying mechanism is typically provided between the mounting flange of the bearing plate and the protective cover – and preferably also in the present power tool. This keying mechanism allows the protective cover to be placed on and removed from the mounting flange only in a specific mounting position. For this purpose, axial grooves are formed on the mounting flange, more precisely on its outer cylindrical surface. In the mounting position, radial projections engage in these axial grooves. These projections are formed on the inside of a hollow cylindrical mounting flange of the protective cover. The mounting position generally corresponds to a position that is not typically used as a working position. After mounting, the protective cover can then be rotated and locked in various working positions by means of a pawl.

[0003] These protective guards are designed to protect the user of the power tool from injuries caused by sparks or similar particles generated during its use. Furthermore, the guard must ensure that, in the event of a tool breakage, it can withstand the fragments of the tool impacting it at very high speeds.

[0004] However, if the power tool is used without this protective guard, there is a high risk of injury, making its use absolutely essential. Despite these risks, these power tools are frequently used without the guard, contrary to the operating instructions, as users sometimes find it cumbersome. Therefore, various approaches exist in the art to at least make it more difficult for the user to remove the guard from the power tool.

[0005] For example, DE 10 2019 104 139 A1 shows an angle grinder in which the view of the guard's markings is partially obstructed to make its removal more difficult. Furthermore, a stop component screwed to the bearing plate is intended to prevent the user from easily removing the guard from the angle grinder. While the stop component can be screwed into the bearing plate via a threaded connection, it cannot be removed without first disassembling the bearing plate.

[0006] DE 20 2019 100921 U1 describes an electric tool comprising a motor with a reduction mechanism housed in a casing. A front tool-holding section is connected to the reduction mechanism. A cover at least partially covers the front tool-holding section and is provided with a stop element. The cover and the casing have corresponding detents for attaching the cover to the casing. The stop element has a section that engages in the detents of the casing.

[0007] WO 2020 / 031866 A1 discloses an electric tool with the features of the preambles of claims 1, 5 and 9. This tool may comprise a motor, a power transmission mechanism connected to the motor, a housing for receiving the motor and the power transmission mechanism, a distal tool holding section, a cover for covering at least part of the distal tool holding section, a first locking mechanism and a second locking mechanism. The first locking mechanism is brought into an unlocked state by a user actuation, while the second locking mechanism is brought into an unlocked state by a separate user actuation.

[0008] DE 10 2006 027576 A1 relates to a protective hood fastening device for power tools. It comprises a fastening element for attaching a protective hood to the body of the tool. The fastening element includes at least one locking element to secure the protective hood against rotation on the body of the power tool.

[0009] DE 10 2006 053305 A1 describes a hand-held power tool for rotating tools, such as disc tools, equipped with a machine housing that has a flange or machine neck. A protective hood, typically made of sheet metal, is attached to this to cover the tool. An anti-rotation device between the machine neck and the protective hood ensures operational safety. The protective hood is positively connected to the machine neck by a clamping band or clamping device and can be released for adjustment.

[0010] DE 10 2007 052683 A1 relates to a hand-held power tool, in particular an angle grinder, with a housing and a flanged neck on which a guard is mounted, forming an area for the tool. It is proposed that at least one device for damping and / or compensating for play between the housing and the guard be provided.

[0011] DE 10 2009 024427 A1 relates to a protective guard for electric hand tools, in particular angle grinders, with a guard plate that covers the disc tool and runs perpendicular to a guard collar. The protective guard can be fixed to the machine neck, with at least one positive locking element provided between the guard collar and the machine neck, which interacts with a corresponding element of the machine neck. An electric hand tool with such a protective guard is also described.

[0012] DE 101 58 334 C1 relates to a power tool, in particular an angle grinder, with a protective guard that can be detachably attached to the spindle neck. The protective guard has a cylindrical collar that is arranged around the spindle neck and interacts with a counter-acting element on the spindle neck to prevent rotation via a cam element. The cam element is connected to a support element outside the collar and is guided radially inwards through an opening in the collar to interact with the counter-acting element. This ensures that the support element is held securely on the collar even when the protective guard is detached.

[0013] DE 10 2008 000732 A1 describes a hand-held power tool comprising a protective hood which is detachably connected to a support part of the power tool. A radially projecting clamping projection is formed on the wall of the opening that defines a receiving opening for the protective hood, wherein a support part, to which the protective hood is attached, has a support stud that can be inserted into the receiving opening and into which a clamping recess for the clamping projection is provided.

[0014] EP 2 119 534 A1 describes a protective hood that can be attached to a power tool, in particular an angle grinder, and that can be pivoted into various operating positions within a limited angular range around the drive spindle. It consists of a body with a sector-shaped wall and several retaining elements arranged coaxially along a partial circular arc. These retaining elements engage with a counterpart on the power tool to fix the protective hood in the selected position.

[0015] However, this solution, known from the prior art, has proven to be very complex, so the present invention aims to reduce the aforementioned disadvantages and to provide a power tool that has a simpler securing device for the protective cover.

[0016] This problem is solved by the subject matter of the independent claims. Further details can be found in the dependent claims.

[0017] According to the invention, this problem is solved in a power tool of the type mentioned at the outset by selecting the locking device from a group comprising at least one locking pin received in the receiving flange, a locking ring preferably secured to the receiving flange by a snap-fit ​​connection or by a press-fit connection, a locking plate screwed to the bearing plate by several locking screws, a locking clip attached to the bearing plate and a locking tab formed on the protective hood.

[0018] This provides simple ways to attach the protective cover to the mounting flange and at least makes it more difficult for the user to remove the cover improperly. Furthermore, these safety devices make any tampering by the user easily detectable. This allows, for example, a safety officer to identify and penalize such tampering. Since this makes the power tool significantly safer, it can also potentially lead to reduced insurance or occupational health and safety premiums.

[0019] It has proven particularly advantageous if, after the protective cover is mounted on the mounting flange, the at least one locking pin can be inserted into a pin receptacle formed on the mounting flange. This allows the at least one locking pin to be inserted into the pin receptacle after the protective cover is mounted on the bearing plate. The locking pin can be inserted into the pin receptacle in such a way that it still protrudes into the axial groove, thereby blocking the corresponding axial groove on the mounting flange and preventing disassembly of the protective cover, as the respective radial projection is blocked by the locking pin. The locking pin is then driven into the pin receptacle.Before the protective cover can be removed, it must be driven further into the pin recess to release the axial groove. This allows the radial projection to pass the locking pin and exit the axial groove during removal. While this makes it possible for the user to remove the protective cover, it requires increased effort and is only possible in a way that makes the tampering easily detectable, for example, during servicing or an internal security check.

[0020] It has also proven advantageous if the protective cover has at least one opening for inserting the at least one locking pin into the pin receptacle. This allows the locking pin to be easily inserted from the outside through the opening, which is preferably formed on a mounting flange of the protective cover, into the pin receptacle. However, the invention also provides for the locking pin to be inserted into the pin receptacle from the inner circumference of the mounting flange, where the receptacle opens into the axial groove. With this type of installation as well, the locking pin naturally projects through the pin receptacle into the axial groove to block the axial groove and thus prevent the protective cover from being removed.

[0021] Removing the locking pin can be further complicated if the pin recess is designed as a blind hole. This prevents the user from driving the locking pin through the recess to remove the protective cover from the bearing plate. Instead, the user would have to drill out the locking pin. Therefore, if the protective cover needs to be replaced, the bearing plate must be replaced along with the protective cover.

[0022] It has also proven particularly effective if the locking device includes a locking cap secured by at least one locking pin on the bearing plate. Especially when the locking cap is installed on the inside of the mounting flange, this ensures that the at least one locking pin can only be removed from the axial groove if the locking cap has been destroyed beforehand, which would be noticeable during an inspection of the power tool.

[0023] In this context, it has also proven advantageous if the locking cap has at least ring-segment-like projections on the side facing away from the tool holder. These projections can, on the one hand, be at least partially penetrated by the locking pin and, on the other hand, provide a stop for the locking pin, thus limiting its insertion depth into the pin receptacle and simultaneously ensuring that the protective cover can only be removed from the bearing plate if the locking cap is first mechanically destroyed or if the locking pins have been drilled out.

[0024] If the locking device is designed as a retaining ring, it has proven advantageous to have a radial collar with locking projections. The axial collar provides a stop surface that limits the locking ring's movement on the mounting flange during installation. The locking projections can engage at least partially in the axial grooves formed in the mounting flange. Preferably, the retaining ring is at least partially located on the inside of the mounting flange, thus facilitating its installation. The retaining ring also ensures that the axial grooves are at least partially blocked, preventing the protective cover from being removed from the mounting flange.

[0025] The protective cover can also be easily prevented from being removed by a retaining ring secured to the mounting flange by a snap-fit ​​or press-fit connection. To attach the retaining ring to the mounting flange, it has proven advantageous to incorporate locking lugs to form a snap-fit ​​connection. In particularly preferred embodiments, these lugs are formed on the retaining projections that engage in the axial grooves. The locking lugs engage in detent seats, which, in a preferred embodiment, are formed on the mounting flange in the area of ​​the axial grooves. This allows the retaining element to be simply placed onto the mounting flange during assembly and locked into place by the snap-fit ​​connection.

[0026] A very simple way to secure the protective cover to the power tool is also achieved using a locking plate, which is screwed to the bearing plate by several locking screws. It has proven particularly effective to tighten the screws from the side facing the tool holder, as this reduces assembly effort. However, the invention also provides for the locking plate to be screwed to the bearing plate from the side away from the tool holder. This further increases protection against unauthorized removal of the protective cover, as the bearing plate must now be removed first to detach the cover. In addition to locking screws, the invention also provides for the locking plate to be fastened by forming. Riveting, self-piercing riveting, clinching, crimping, and crimping have proven particularly advantageous in this regard.Other ways to attach the locking plate include gluing, welding (especially laser welding), vulcanizing, or overmolding to further complicate the removal of the locking plate.

[0027] In this context, it has also proven advantageous if the locking screws used for the fastening have a locking mechanism to prevent unauthorized loosening. This can be achieved, for example, by a special shape of the screw head that allows the locking screw to be screwed into the screw receptacle but prevents it from being loosened, by an insert that is placed in the tool recess of the screw head, or by a special screw head that shears off the locking screw when a limit torque is exceeded.

[0028] To facilitate the mounting of the locking device on the power tool, it has proven advantageous to have a centering feature and / or a centering collar on the bearing plate and / or the locking plate. In this context, it has proven particularly beneficial if the centering feature includes an axial collar formed on the bearing plate. The locking device can then be placed onto this axial collar.

[0029] It has also proven advantageous to have locking wings assigned to the locking plate that at least partially cover the protective cover. This overlap is particularly advantageous in an area where no axial groove of the coding terminates, thus enabling the user to easily check the alignment of the protective cover relative to the mounting flange. To achieve improved stability of the locking device, it has also proven beneficial to connect the locking wings to each other with a retaining ring. This design can be used, in particular, with a bearing plate whose mounting flange is formed without coding on its outer circumference. This eliminates the need for coding, which has a positive impact on manufacturing costs.The protective cover can therefore be easily placed on the mounting flange in any orientation. The locking wings or the end ring of the end plate then fix the axial position of the protective cover on the bearing plate.

[0030] If the locking device is designed as a locking clip, it has proven advantageous to have a radially adjustable locking lug associated with the locking clip. This lug engages in a recess formed on the protective cover, preferably on the mounting flange of the protective cover. The recess points radially outwards. This allows the locking clip to easily engage in the recess when the protective cover is mounted on the receiving flange and is in its installed position. When the axial groove and the radial projections of the coding are aligned, the locking clip and the recess are also opposite each other. With the locking clip's locking lug engaged in the recess in this position, the protective cover cannot be removed from the receiving flange.The locking lug is preferably attached to the locking clip on only one side, preferably on a long side. Alternatively, the locking lug can also be attached to one or two opposite short sides of the locking clip. Multiple locking clips can be used. The locking clip is attached to the mounting flange in a way that prevents axial movement but allows it to rotate.

[0031] To facilitate mounting the protective cover onto the mounting flange, it has proven particularly advantageous to have a chamfer on the locking lug. This chamfer simplifies the mounting of the protective cover onto the mounting flange, as it ensures that the locking lug can deflect radially inwards when the cover is mounted. Furthermore, it has proven beneficial if the chamfer is designed in such a way that the locking clip of the locking device is radially adjusted perpendicular to the mounting direction during installation. This ensures that the protective cover can be easily mounted.The insertion ramp is only formed on one side, which ensures that when the protective cover is removed from the receiving flange, the limit of the projection formed on the protective cover prevents the radial adjustment of the locking clip, whose locking lug engages in the projection.

[0032] It has also proven advantageous if the retaining clip is movably mounted circumferentially in an annular groove formed on the mounting flange of the bearing plate. To secure the retaining clip in the annular groove of the mounting flange during assembly, special retaining structures, such as knobs, on the retaining clip have proven beneficial; in a particularly preferred embodiment, these structures are triangular in shape. After the protective cover is mounted, the retaining clip, whose locking lug engages in the recess, is rotationally fixed to the protective cover. This makes it possible to secure the axial position of the protective cover in the assembled position. At the same time, however, it remains possible to rotate the protective cover and the rotationally fixed retaining clip relative to the bearing plate.When the protective cover is rotated from the mounting position, the locking tab of the locking clip always remains radially offset outwards and engaged in the recess, allowing the protective cover to be rotated together with the locking clip.

[0033] If the locking device is designed as a locking tab, it has proven advantageous for the locking tab formed on the protective cover to provide a spring action. This causes the locking tab to deform elastically when the protective cover is mounted on the receiving flange. Once the protective cover is mounted on the receiving flange, the pre-tensioned locking tab is returned to its position in the annular groove formed on the receiving flange, thus securing the protective cover to the receiving flange.

[0034] Within the scope of the invention, it has also proven advantageous if the locking tab can be mechanically moved into a locking position. For this purpose, an auxiliary tool, such as an embossing die, can be used, with which the locking tab can be pressed into the annular groove after the protective cover has been mounted on the receiving flange. Except for one annular groove, the receiving flange can be designed without any markings.

[0035] The invention will now be explained in more detail using several exemplary embodiments shown in the drawings; these show: Fig. 1 a perspective view of the gearbox head of a power tool with a protective cover in an assembly position, Fig. 2 a cross-section through a gearbox head with a first embodiment of a locking device with a protective cover in an assembly position, Fig. 3 a longitudinal section through the gearbox head with the first embodiment of the locking device, Fig. 4 a perspective view of a locking cap that is part of a second embodiment of the locking device, Fig. 5 a detail through a longitudinal section of a gearbox head with the locking cap secured to the gearbox head, Fig. 6 a cross-section through a gearbox head with the second embodiment of the locking device, Fig. 7 a perspective view of a retaining ring with locking lugs that is part of a third embodiment of the locking device, Fig.8a section through a longitudinal section of a gear head with the retaining ring secured to the gear head from the . Figure 7 Fig. 9 a longitudinal section through the gearbox head with the third embodiment of the locking device designed as a retaining ring with locking lugs, Fig. 10 a perspective view of a fourth embodiment of the locking device, Fig. 11 a detail through a longitudinal section of a gearbox head with the fourth embodiment of the locking device secured to the gearbox head, Fig. 12 a perspective detail of a power tool with the fourth embodiment of the locking device, Fig. 13 a perspective view of a power tool with a fifth embodiment of the locking device designed as a locking plate, which is screwed to the gearbox head, Fig. 14 a perspective view of a bearing plate of the gearbox head made of the Figure 13Fig. 15 shows a perspective view of a power tool with a further embodiment of the safety device designed as a safety plate, Fig. 16 shows a longitudinal section through a gearbox head according to the Figure 15 with the locking plate serving as a locking device, Fig. 17 a perspective view of a bearing plate of the gearbox head from the Figure 16 Fig. 18 shows another embodiment of a locking device designed as a locking plate with locking wings; Fig. 19 shows another embodiment of the locking plate with a retaining ring; Fig. 20 shows a longitudinal section through a gear head with a locking plate that is screwed to the bearing plate from the side facing away from the tool holder; Fig. 21 shows a perspective detail view of a bearing plate on which a locking clip is mounted, serving as a locking device; Fig. 22 shows a perspective view of the locking clip from the Figure 21, Fig. 23 a sectional view along a longitudinal section through the gear head from the Figure 21 Fig. 24 a cutaway detail view of the protective cover attached to the mounting flange by the locking clip, Fig. 25 a cross-section through a gear head with a protective cover attached by the locking clip, Fig. 26 a perspective view of a protective cover on which the locking device is formed in the form of a locking tab, Fig. 27 a perspective view of the protective cover that can be secured to the mounting flange of the bearing plate by the locking tab, Fig. 28 a perspective view of a protective cover on which the locking device is formed in a further embodiment of a locking tab, Fig. 29 a perspective view of the protective cover that can be secured to the mounting flange of the bearing plate by the further embodiment of the locking tab from the Figure 28, Fig. 30 a perspective view of a protective hood on which a third embodiment of a locking tab is formed, and Fig. 31 a perspective view of the protective hood secured to the receiving flange of the bearing plate by the third embodiment of the locking tab.

[0036] Figure 1Figure 1 shows a perspective view of a section of a power tool 1, namely an angle grinder 2. This tool has a housing 3 in which a drive motor 4 is mounted. This drive motor 4 rotates a rotor shaft 5, which is connected via a bevel gear 6 to a tool spindle 7, which in turn rotates the spindle. At the end of the tool spindle 7 is a tool holder 8 to which an insert tool, such as a grinding or cutting disc, can be attached. The bevel gear 6 is mounted in a gearbox 9, which is connected to a bearing plate 10 that is screwed to the gearbox 9. The bearing plate 10 has a spindle bore 11 for the tool spindle 7, in which the tool spindle 7 is rotatably mounted.A mounting flange 12 is formed on the bearing plate 10, to which a protective hood 13 can be rotatably mounted to protect the user when processing workpieces. For mounting the protective hood 13, a keying 14 is formed between the protective hood 13 and the mounting flange 12, which allows the user to attach the protective hood 13 to the mounting flange 12 in only one mounting position. In the illustrated embodiment, this keying 14 consists of several axial grooves 15 formed on the outer surface of the mounting flange 12, into which inwardly projecting radial projections 16 engage, which are formed on a mounting flange 17 of the protective hood 13. In the assembled state, i.e., when the protective cover 13 is attached to the receiving flange 12, the inwardly pointing radial projections 16 of the protective cover 13 engage in an annular groove 18 which is formed on the receiving flange 12.Guided within this annular groove 18, the user is able to rotate the protective hood 13 to adapt it to different working positions. However, axial adjustment of the protective hood 13 is only possible in the assembly position due to the coding 14.

[0037] In the Figure 1 In the illustrated embodiment, several openings 19 are visible in the protective cover 13. After the protective cover 13 has been mounted on the receiving flange 12, locking pins 20 can be inserted through these openings. These locking pins form a locking device 21, which at least makes it more difficult to remove the protective cover 13 from the receiving flange 12. The function of these locking pins 20 is explained below with reference to the Figures 2 and 3 explained in more detail.

[0038] Figure 2The diagram shows a cross-section of the cut bearing plate 10 of the gearbox head 9. This clearly shows that in the assembly position shown in the Figure 2 As shown, the passages 19 with pin receptacles 22 are aligned with the mounting flange 17. In this, in the Figure 2In the illustrated orientation, the locking pins 20 can now be inserted through the openings 19 of the protective cover 13 into the pin receptacles 22 formed in the bearing plate 10. In the assembled state, the locking pins 20 protrude beyond the pin receptacles 22 and into the axial groove 15, thereby blocking the radial projections 16 in such a way that the protective cover 13 cannot be removed from the mounting flange 12, even in the assembled position. The locking pins 20 thus block a portion of the axial grooves 15 of the coding 14, making disassembly of the protective cover 13 impossible. However, rotating the protective cover 13, guided in the annular groove 18, from the assembled position to the working position remains possible.

[0039] The locking of the protective hood 13, secured to the receiving flange 12 of the bearing plate 10, by the locking pins 20 is also clearly shown in the longitudinal section, which is shown in the Figure 3 is depicted. In the Figures 1 to 3 In the illustrated embodiment, 3 locking pins 20 are used. However, it is also possible to use any other number of locking pins 20.

[0040] In a second embodiment of the locking device 21, which is located in the Figures 4 to 6 As shown, the locking device 21 comprises, in addition to the locking pin 20, a locking cap 23. A perspective view of the locking cap 23, which is preferably made of plastic, is shown in the Figure 4shown. In particular, projections 24 become visible, which on the one hand serve to mount the locking cap 23 on the receiving flange 12 and on the other hand provide a stop 26 for the locking pin 20, as can be seen in particular from the detailed view shown in the Figure 5 is shown.

[0041] From this Figure 5 It becomes particularly clear that, in this embodiment, the locking pin 20 passes radially through an opening 25 formed in the locking cap 23 and then comes to rest against the projection 24. The projection 24 limits the insertion depth of the locking pin 20, thus facilitating its installation.

[0042] As well as the one in the Figure 6As can be seen from the cross-section shown, in this embodiment the locking pin 20 is also received in the pin receptacle 22 formed on the bearing plate 10. However, the locking pin 20 projects into the locking cap 23, which is arranged on the inner circumferential side of the receiving flange 12 of the bearing plate 10. The locking pin 20 thus comes into contact with one of the projections 24, which in the illustrated embodiment are formed on the side facing away from the tool holder 8. The locking pin 20 secures the locking cap 23 to the bearing plate 10. Although only one locking pin 20 is used in the embodiment shown here, the invention also provides for multiple locking pins 20.The locking cap 23 prevents the user from pushing the locking pin 20 out of the annular groove 18 through the pin receptacle 22, as the locking cap 23 – specifically the projection 24 – acts as a stop 26, effectively preventing manipulation by the user and thus preventing the user from removing the protective cover 13. The locking cap 23 is held in the space defined by the receiving flange 12 and the spindle passage 11.

[0043] Figure 7 Figure 1 shows a third embodiment of the locking device 21, which comprises a locking ring 27 that is attached to the receiving flange 12 by a snap-fit ​​connection. For this purpose, locking lugs 28 are formed on the locking ring 27, specifically on locking projections 29 that are associated with a radial collar 30.

[0044] As in particular the Figure 8As can be seen in the figure, which shows a detail of the locking device 21 secured to the bearing plate 10 according to the third embodiment, the locking projections 29 engage in the axial grooves 15 formed on the receiving flange 12. The locking lugs 28 engage in detent seats 31 formed on the receiving flange 12 of the bearing plate 10. The locking projections 29 block the path for the radial projections 16. Due to the locking connection between the retaining ring 27 and the receiving flange 12, the protective cover 13 cannot be removed without destroying the retaining ring 27.

[0045] The one in the Figure 9 The longitudinal section through the power tool 1 shown clearly demonstrates once again that the locking projections 29 of the retaining ring 27 prevent the protective cover 13 from being removed. Figure 9The figure also shows that the radial collar 30 comes into contact with the front face of the receiving flange 12, while a hollow cylindrical section 32 of the retaining ring 27 is supported on the inner circumferential side of the receiving flange 12.

[0046] Another embodiment of the locking device 21, which includes a retaining ring 27, is described in the Figure 10 shown. In this embodiment, the retaining ring 27 is secured to the receiving flange 12 by a press fit. Similar to the retaining ring 27 according to the Figures 7 to 9 The one in Figure 10 The retaining ring 27 shown has a radial collar 30 on which retaining projections 29 are formed. These retaining projections 29 engage in the axial grooves 15 and also form the press fit by which the retaining ring 27 is attached to the receiving flange 12.

[0047] The detailed view, which is in the Figure 11The figure shows once again the retaining ring 27 secured to the mounting flange 12 of the bearing plate 10 by the press fit. It is clearly visible here that the retaining projections 29 engage in the axial grooves 15 and thereby prevent the protective cover 13 from detaching from the mounting flange 17 of the bearing plate 10 by blocking the radial projections 16. Figure 11 It also becomes clear that the radial collar 30 of the retaining ring 27 comes into contact with the end face of the receiving flange 12, while a hollow cylindrical section 32 of the retaining ring 27 is supported on the inner circumference of the receiving flange 12, similar to the embodiment according to the Figures 7 to 9 was the case.

[0048] The Figure 12Figure 1 shows a perspective view of the retaining ring 27, which is attached to the receiving flange 12 by a press fit. It is clearly visible that its retaining projections 29 engage in the axial grooves 15 formed on the receiving flange 12 of the bearing plate 10. The protective cover 13, which is shown in the Figure 12 For the sake of clarity, the part shown in the annular groove 18 of the mounting flange 12 can be rotated. However, disassembly is impossible because the axial grooves 15 are blocked by the locking projections 29.

[0049] Figure 13Figure 1 shows a further embodiment of the locking device 21, in which the locking device 21 is designed as a locking plate 33, which is screwed to the bearing plate 10 by several locking screws 34. The screwing is carried out from the side facing the tool holder 8. Each locking screw 34 is associated with a screw locking device 35 to prevent unauthorized loosening of the locking screws 34. In the illustrated embodiment, this screw locking device 35 has a specially shaped screw head 36 which allows the locking screws 34 to be screwed into the screw receptacles 37 formed on the bearing plate 10, but prevents the locking screws 34 from being loosened. In the embodiment shown in the Figure 13In the illustrated embodiment of the locking plate 33, radial locking wings 38 are formed on it, which partially cover the axial grooves 15. These also facilitate assembly, as they promote alignment and centering of the locking plate 33. The locking plate 33 can be manufactured in one piece, as shown in Figure 13 shown, or multi-part, as a sheet metal stamping and bending part, light metal casting and / or plastic part, in particular glass fiber reinforced.

[0050] Figure 14 Figure 1 also shows a perspective view of a bearing plate 10 of the gearbox head 9. In this embodiment, a centering feature 39 is formed on the end face of the receiving flange 12, which enables the locking plate 33 to be aligned relative to the bearing plate 10.

[0051] During the Figure 15In the illustrated embodiment of the locking plate 33, the locking plate 33 covers the openings of the axial grooves 15 formed on the bearing plate 10, thus eliminating the need for a keying 14 between the receiving flange 12 and the protective cover 13. In particular, the receiving flange 12 can therefore be formed without keying. The protective cover 13 can now be placed on the receiving flange 12 in any position and is then axially secured by the locking plate 33, which is screwed to the bearing plate 10 by the locking screws 34.

[0052] Figure 16 Figure 1 shows a longitudinal section of the protective hood 13 secured to the bearing plate 10 by the locking plate 33. This also clearly shows that the locking plate 33 covers the radial projections 16 of the protective hood 13, which formed part of the coding 14 in the previously described embodiments.

[0053] The Figure 16 The design of the bearing plate 10 can also be seen. It becomes clear that the receiving flange 12 terminates in a shoulder 40 against which the protective cover 13 rests. Furthermore, a recess 41 is visible in the area of ​​the shoulder 40, which serves to accommodate a ring seal 42. Additionally, a centering collar 51 is visible on the receiving flange 12, which serves as a centering element 39 and facilitates the centering of the locking plate 33.

[0054] Figure 17 Figure 1 shows, once again in an isolated perspective view, the design of the corresponding bearing plate 10. In particular, the shoulder 40, against which the protective cover 13 rests in the assembled state, is clearly visible. Furthermore, the Figure 17 also to remove the screw receptacles 37, to which the locking plate 33 is screwed, and the centering collar 51, on which the locking plate 33 is centered or aligned.

[0055] Figure 18Figure 1 shows another embodiment of the locking plate 33. Here, the diameter of the locking plate 33 is dimensioned such that the axial grooves 15 formed on the receiving flange 12 are not covered. To secure the protective cover 13, locking wings 38 are formed on the locking plate 33, which locally overlap the protective cover 13 to secure its axial position on the receiving flange 12.

[0056] Another embodiment of the locking plate 33 is described in the Figure 19 shown. In this embodiment, which is a further development of the embodiment from the Figure 18 As shown, the locking wings 38 are connected to each other by a termination ring 43, which increases the contact area of ​​the locking plate 33 with the protective cover 13. In this embodiment as well, the locking plate 33 is dimensioned so that the axial grooves 15 are not covered.

[0057] During the Figure 20In the illustrated embodiment, the locking plate 33 is screwed to the bearing plate 10 from the side facing away from the tool holder 8. This means that the bearing plate 10 must first be removed to dismantle the protective hood 13, thus providing increased protection against unauthorized removal of the bearing plate 10.

[0058] Another embodiment according to the invention is described in the Figures 21 to 25 As shown. In this embodiment, the locking device 21 comprises at least one locking clip 44 with a radially adjustable locking lug 45. As shown in the Figure 21 The retaining clip 44 is inserted into the annular groove 18 of the bearing plate 10 and secured there by studs 46, which facilitates the mounting of the protective cover.

[0059] These 46 studs are particularly the ones in the Figure 22 The perspective view of the safety clip 44 is recognizable. Figure 22It can also be seen that the locking lug 45 is attached to the locking clip 44 only on one short side. A guide chamfer 47 is formed on the locking lug 45 of the locking clip 44.

[0060] This chamfer 47 ensures that when the protective cover 13 is slid onto the receiving flange 12, the locking lug 45 can retract radially – i.e., perpendicular to the mounting direction 48 of the protective cover 13 – as shown in the Figure 23 as indicated. Only when the radial projections 16 of the protective hood 13 are received in the annular groove 18 is the locking lug 45 again moved radially outwards into a recess 49, which is formed on the mounting flange 17 of the protective hood 13, as shown in the Figure 24can be removed. Since the insertion ramp 47 is only formed on the side of the locking lug 45 facing the tool holder 8, this ensures that the locking lug 45 cannot move out of the recess 49 when attempting to remove the protective cover 13 from the mounting flange 12.

[0061] The one in Figure 25 The sectional view shown depicts the protective hood 13 secured to the mounting flange 12 in a working position. As these Figure 25 As shown, the locking lug 45 is also engaged in the recess 49 in the working position, which is formed on the mounting flange 17 of the protective hood 13. This ensures that the protective hood 13 is rotationally fixed to the locking clip 44, so that the locking clip 44 can rotate in the annular groove 18.

[0062] In the Figure 26A protective cover 13 is shown, which has a locking tab 50 that is plastically deformed by an embossing tool after the protective cover 13 has been mounted on the receiving flange 12 (in Figure 26 and 27 (not shown). The deformed locking tab 50 engages in the annular groove 18, which is formed on the receiving flange 12 of the bearing plate 10, as shown in the Figure 27 can be removed. This prevents the protective cover 13 from being removed from the mounting flange 12.

[0063] A similar design is found in the Figures 28 and 29 The protective covers shown are visualized. Here, the locking tab 50 can be more easily plastically deformed, for example bent, since the locking tab 50 is only connected at one end to the mounting flange 17 of the protective cover 13. Therefore, when the protective cover 13 is now mounted on the receiving flange 12 – as shown in the Figure 29As shown, the locking tab 50 can be mechanically adjusted into the annular groove 18 which is formed in the bearing plate 10.

[0064] Figure 30 and Figure 31 Figure 1 shows a further embodiment of the locking device 21, in which the locking tab 50, formed on the protective cover 13, provides a spring action. When the protective cover 13 is slid onto the receiving flange 12, the locking tab 50 is elastically displaced radially outwards. When the protective cover 13 is slid onto the receiving flange 12, the locking tab 50 snaps into the annular groove 18 formed on the receiving flange 12. This secures the protective cover 13 to the receiving flange 12.

[0065] Depending on the material used and / or its thickness, the desired spring effect can be achieved in the Figures 30 and 31The locking tab 50 shown cannot be reached. In this case, the protective cover 13 is initially pushed onto the mounting flange 12 with the locking tab 50 undeformed. After assembly, the locking tab 50 is then plastically deformed using an embossing die and engages in the annular groove 18, thus preventing the user from removing the protective cover 13 from the mounting flange 12 of the bearing plate 10. List of reference symbols

[0066] 1 Power tool 2 Angle grinder 3 Housing 4 Drive motor 5 Rotor shaft 6 Angle gearbox 7 Tool spindle 8 Tool holder 9 Gear head 10 Bearing plate 11 Spindle bore 12 Mounting flange 13 Protective hood 14 Coding 15 Axial groove 16 Radial projection 17 Mounting flange 18 Ring groove 19 Bore 20 Locking pin 21 Locking device 22 Pin receptacle 23 Locking cap 24 Projection 25 Opening 26 Stop 27 Retaining ring 28 Detent lug 29 Locking extension 30 Radial collar 31 Detent seat 32 Hollow cylindrical section 33 Locking plate 34 Locking screw 35 Screw locking device 36 Screw head 37 Screw receptacle 38 Locking wing 39 Centering 40 Shoulder 41 Groove 42 Ring seal 43 End ring 44 Locking clip 45 Locking lug 46 Stud 47 Leading chamfer 48 Mounting direction 49 Protrusion 50 Locking tab 51 Centering collar

Claims

1. Power tool (1), in particular angle grinder (2), having a drive motor (4) which is accommodated in a housing (3) and drives a rotor shaft (5), having a tool spindle (7) which comprises a tool holder (8) and is connected to the rotor shaft (5) by an angular gear (6) which is accommodated in a gear head (9), having a bearing plate (10) which comprises a spindle passage (11), in which the tool spindle (7) is rotatably received, wherein the bearing plate (10) comprises a receiving flange (12) on which a protective cover (13) can be rotatably mounted, the removal of which from the receiving flange (12) is at least made more difficult by a securing device (21), wherein the securing device (21) comprises at least one securing pin (20) received in the receiving flange (12), characterized in that the at least one securing pin (20) is inserted into a pin receptacle (22) formed on the receiving flange (12) after the protective cover (13) has been mounted on the receiving flange (12) and projects into an axial groove (15) of the receiving flange (12), whereby a corresponding axial projection (15) of the protective cover (13) on the receiving flange (12) is blocked and disassembly of the protective cover (13) is thereby prevented .

2. Power tool (1) according to claim 1, characterized in that at least one passage (19) is formed on the protective cover (13) for inserting the at least one securing pin (20) in the pin receptacle (22).

3. Power tool (1) according to one of claims 1 or 2, characterized in that the securing device (21) comprises a securing cap (23) which is secured to the bearing plate (10) by the at least one securing pin (20), and in particular characterized in that the securing cap (23) is inserted on the inside of the receiving flange (12).

4. Power tool (1) according to claim 3, characterized in that the securing cap (23) comprises at least annular segment-like projections (24) on the side facing away from the tool holder (8).

5. Power tool (1), in particular angle grinder (2), having a drive motor (4) which is accommodated in a housing (3) and drives a rotor shaft (5), having a tool spindle (7) which comprises a tool holder (8) and is connected to the rotor shaft (5) by an angular gear (6) which is accommodated in a gear head (9), comprising a bearing plate (10) which has a spindle passage (11) and in which the tool spindle (7) is rotatably accommodated, wherein the bearing plate (10) comprises a receiving flange (12) on which a protective cover (13) can be rotatably mounted, the removal of which from the receiving flange (12) is at least made more difficult by a securing device (21), wherein the securing device (21) comprises a securing plate (33) which is screwed to the bearing plate (10) by a plurality of securing screws (34) and which is arranged centrally to the tool spindle (7), characterized in that the securing plate (33) is screwed to the bearing plate (10) from the side facing the tool holder (8) and the securing screws (34) used for the screw connection comprise a screw lock to prevent unauthorized loosening.

6. Power tool (1) according to claim 5, characterized in that a centring (39) and / or a centring collar (51) is formed on the bearing plate (10) and / or on the securing plate (33).

7. Power tool (1) according to claim 6, characterized in that the centring (39) comprises an axial collar which is formed on the bearing plate (10).

8. Power tool (1) according to one of claims 5 to 7, characterized in that securing wings (38) are assigned to the securing plate (33), which at least partially cover the protective cover (13), and in particular characterized in that the securing wings (38) are connected to one another by an end ring (43).

9. Power tool (1), in particular angle grinder (2), having a drive motor (4) which is accommodated in a housing (3) and drives a rotor shaft (5), having a tool spindle (7) which comprises a tool holder (8) and is connected to the rotor shaft (5) by an angular gear (6), which is received in a gear head (9), with a bearing plate (10) which comprises a spindle passage (11) and in which the tool spindle (7) is rotatably received, the bearing plate (10) having a receiving flange (12) on which a protective cover (13) can be rotatably mounted, the removal of which from the receiving flange (12) is at least made more difficult by a securing device (21), characterized in that the securing device (21) is selected from a group which comprises a securing ring (27) preferably secured to the receiving flange (12) by a latching connection or by a press connection, a securing clip (44) fastened to the bearing plate (10) with a radially adjustable securing lug (45) and a plastically deformable securing lug (50) formed on the protective cover (13), wherein the latching connection (27) provides latching lugs (28) which are formed on securing projections (29) of a radial collar (30) of the securing ring (27), and wherein axial grooves (15) are formed on the outer cylindrical surface of the receiving flange (12), and wherein the latching lugs (28) are formed on the securing projections (29), which engage in the axial grooves (15).

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