Receptacle for grinder tools

The invention is based on a tool receiver for a grinder, in particular for a handheld angle grinder (10), having a carrier device (12, 14, 16, 182, 184, 300), via which an application tool (18, 32, 186, 188) can be actively connected to a drive shaft (54).It is proposed that the application tool (18, 32, 186, 188) be actively connectable to the carrier device (14, 16, 182, 184) via at least one detent element (24, 26, 190, 192, 194, 196, 198, 200, 302) movable against a spring force that snaps into place in an operating position of the application tool (18, 32, 186, 188) and immobilizes the application tool (18, 32, 186, 188) with positive engagement.

BACKGROUND OF THE INVENTION

The invention is based on a tool for a grinder.

A tool receiver for a grinder for a handheld angle grinder is made known in EP 0 904 896 A2. The angle grinder comprises a drive shaft that carries a thread on the tool side.

The tool receiver for a grinder comprises a carrier and a tensioning nut. To install a sanding disk, the carrier with an installation opening is pushed onto a collar of the drive shaft and tightened with positive engagement against a bearing surface via the tensioning nut. The carrier has a collar extending in the axial direction on the tool side that comprises radially-situated recesses on two opposite sides on its outer circumference that extend in the axial direction to a base of the collar. Starting at the recesses, one groove each extends around the outer circumference of the collar against the driving direction of the drive shaft. The grooves are closed against the driving direction of the drive shaft and taper axially starting at the recesses against the driving direction of the drive shaft.

The sanding disk comprises a hub having an installation opening in which two tongues point radially inward on opposite sides. The tongues can be inserted in the recesses in the axial direction and then in the grooves in the circumferential direction, against the driving direction. The sanding disk is immobilized in the grooves in the axial direction via the tongues with positive engagement and in the tapering contour of the grooves via non-positive engagement. During operation, the adhesion increases as a result of reaction forces acting on the sanding disk, which counteract the driving direction.

In order to prevent the sanding disk from spinning off of the carrier when the brake is applied to the drive shaft, a stopper is located in the vicinity of a recess on the circumference of the collar that is supported in an opening in a fashion that allows it to move in the axial direction. In a working position with the sanding disk pointing downward, the stopper is displaced axially in the direction of the sanding disk by means of the force of gravity, closes the groove in the direction of the recess, and blocks movement of the tongue located in the groove in the driving direction of the drive shaft.

SUMMARY OF THE INVENTION

The invention is based on a tool receiver for a grinder, in particular for a handheld angle grinder, having a carrier device via which an application tool can be actively connected to a drive shaft.

It is proposed that the application tool be actively connectable to the carrier device via at least one detent element movable against a spring force, which detent element snaps into an operating position of the application tool and immobilizes the application tool with positive engagement. Due to the positive engagement, a high degree of reliability can be achieved, and a simple and cost-effective, tool-free, rapid mounting system can be achieved. The application tool can be reliably prevented from spinning off, even when the brake is applied to the drive shaft, which can result in high brake torques.

The detent element can immobilize the application tool with positive engagement directly or indirectly via an additional component, for example, via a locking lever or plunger, etc. that is supported in a fashion that allows it to rotate and/or be displaced axially and is coupled to the detent element. The detent element can immobilize the application tool directly and/or indirectly with positive engagement in various directions, such as in the radial direction, in the axial direction, and/or, particularly advantageously, in the circumferential direction. It is also possible that, due to the positive fixation of the application tool with the detent element in a first direction, e.g, in the radial direction, the application tool is immobilized in a second direction with positive engagement by means of a component separated from the detent element.

The movable detent element can be designed in various forms appearing practical to one skilled in the art, e.g., as an opening, projection, peg, bolt, etc., and it can be located on the application tool or on the carrier device.

Moreover, an advantageous encoding can be achieved by means of the positive engagement, so that only specified application tools can be secured in the tool receiver for a grinder. The carrier device can be designed at least partially as a removable adapter part, or it can be connected with the drive shaft in non-detachable fashion due to a non-positive, positive, and/or bonded connection.

Various application tools appearing practical to one skilled in the art can be secured with the tool receiver for a grinder, such as application tools for separating, grinding, roughing, brushing, etc. A tool receiver according to the invention can also be used to secure a grinding plate of an eccentric grinding machine.

The spring force can be designed to act in various directions, such as in the circumferential direction or, particularly advantageously, in the axial direction, whereby a solution can be achieved that is simple in design. The spring force can further be used to immobilize the application tool in the circumferential direction as well as in the axial direction.

In a further embodiment of the invention it is proposed that a drive torque be transferrable via a positive connection between the application tool and the carrier device. A high drive torque can be transferred reliably, and a drive torque can be prevented from acting on a frictional connection.

As an advantage, the application tool can be connected to the carrier device via a carrier element located on the application tool and/or the carrier device and extending in the axial direction, that can be guided through at least one area of a slot of the corresponding counter-element, displaced along the slot, and immobilized in an end position by the detent element. Using the carrier element extending in the axial direction, a securing in the circumferential direction and the axial direction can be achieved, wherein the application tool is advantageously immobilized with positive engagement in the axial direction via a transfer surface of the carrier element. A high degree of reliability can be achieved and additional components, weight, mounting effort, and costs can be achieved.

In one embodiment it is proposed that the detent element be formed by an elastically deformable component, wherein additional spring elements are spared, and simple, cost-effective designs can be achieved.

Advantageously, at least one detent element producing the spring force is designed as an integral part of the tool hub of the application tool. The tool hub is usually produced out of a relatively thin material that can be designed with a simple construction that is elastically deformable. It is also feasible, however, that at least one spring element is designed as an integral part of a component of the carrier device, or it is formed by an additional component, wherein the tool hub can be designed independent of a spring function.

In order to make a large spring deflection of the tool hub possible, at least one recess is advantageously provided in a component of the carrier device forming a bearing surface for the application tool, into which a part of the tool hub is elastically pressed in an operating position of the application tool.

In a further embodiment of the invention it is proposed that the slot be provided in the tool hub of the application tool, and that at least one detent element be formed by a part of the tool hub in the vicinity of the slot; in fact, particularly advantageously, the slot comprises a wide area and at least one narrow area forming the detent element in front of an end position of the carrier element. Simple, cost-effective and, in particular, essentially flat tool hubs can be achieved that can be handled easily and in space-saving fashion during manufacture and subsequent storage without the tool hubs interlocking on top of each other or with other objects. In addition to a narrowed area, however, an axial raised part in the tool hub forming the detent element would also be feasible in principle.

It is further proposed that at least one detent element is supported in a fashion that allows it to move against a spring element. A large displacement of the detent element during mounting of the application tool can be achieved by means of the detent element supported in movable fashion, by way of which a large overlap between two corresponding detent elements and a particularly reliable positive connection can be achieved on the one hand and, on the other, a very audible snap-in noise can be achieved that signals to the user in advantageous fashion that the snap-in procedure was completed as desired.

The detent element can be designed to be movable in various directions against a spring element, such as in the circumferential direction or, particularly advantageously, in the axial direction, by way of which a simple design can be achieved.

The detent element can even be supported in movable fashion in a component in a bearing, e.g., in a flange of the carrier device or in a tool hub of the application tool. Advantageously, the detent element can also be firmly connected to a component supported in movable fashion in a bearing in non-positive, positive, and/or bonded fashion, or it can be designed integrally connected with this, e.g., with a component supported on the drive shaft or a tool hub of the application tool.

If the detent element can be released from its locked position using a release button and, in particular, if it is movable against the spring element, the snap-in connection can be reliably prevented from coming loose, e.g., by means of brake torque, and safety can be increased. Operation of the application tool in two circumferential directions can be made possible in principle, and comfort during installation and removal of the application tool can be increased.

If the application tool is connected to the carrier device in the circumferential direction via at least a first element and, in the axial direction via at least a second element, simple and cost-effective tool hubs can be achieved that can advantageously be designed flat in shape. An interlocking of the tool hubs during manufacture and storage can be prevented, and good handling of the application tool with its tool hubs can be achieved. Moreover, the components can be advantageously designed for their function, i.e., either for immobilization in the circumferential direction or immobilization in the axial direction. The elements can be formed by a component or, advantageously, by separate components. The tool hubs can be designed simply and advantageously with a closed centering hole, and a low-vibration movement of the application tool can be achieved. Moreover, by selecting a suitable diameter for the centering hole, it can be ensured that application tools provided for the tool receiver for a grinder according to the invention can be secured to traditional grinders via heretofore known fastening devices, and, in fact, via fastening devices in particular with which the application tool can be immobilized on the drive shaft with a tensioning nut and a tensioning flange against a bearing surface in the axial direction with positive engagement and, in the circumferential direction, via non-positive connection.

Moreover, at least one detent element extending in the axial direction can advantageously be snapped into place in a recess of a tool hub of the application tool corresponding to the detent element in an operating position of the application tool in the axial direction, and the application tool can be immobilized with positive engagement in the circumferential direction. Using a means of attaining the object of the invention having a simple design, an advantageous positive connection can be achieved in a circumferential direction and, preferably, in both circumferential directions. The detent element extending in the axial direction can be formed by a separate bolt or an integrally-moulded peg that is produced by means of a deep-drawing procedure, etc.

If at least one detent element is integrally-moulded to a discoid component and/or if at least two elements for immobilizing the application tool in the axial direction are integrally-moulded to a discoid component, additional components, mounting effort, and costs can be spared. Moreover, compression connections between individual components and weak points resulting therefrom can be avoided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows an angle grinder10from above having an electric motor—not shown in greater detail—located in a housing96. The angle grinder10can be guided via a first handle98extending in the longitudinal direction and integrated in the housing96opposite to a cutoff wheel18and via a second handle102extending at an angle to the longitudinal direction secured to a drive housing100in the vicinity of the cutoff wheel186.

Using the electric motor, a drive shaft54can be driven via a gear mechanism, not shown in greater detail, on its end pointing toward the cutoff wheel186of which a carrier device182is located (FIGS.2and3).

The carrier device182comprises a driving flange256. The driving flange256is screwed into place on the drive shaft54via a thread258and, with a face260pointing in the direction44opposite to the cutoff wheel186, extends to a collar262on the drive shaft54. It would also be possible to connect a driving flange with a drive shaft in non-detachable fashion, or to design it integrated with a drive shaft. Three driving pins202,204,206are pressed into the driving flange256that extend in the axial direction38over an axial bearing surface264of the driving flange256for the cutoff wheel186, and that are evenly spaced in the circumferential direction. Heads are integrally-moulded on the driving pins202,204,206on the ends pointing toward the cutoff wheel186. The head has a larger diameter than the remaining part of the driving pin202,204,206and forms a support surface278in the direction of the driving flange256. A centering hole266for the cutoff wheel186extending in the axial direction38is integrally-moulded in the bearing surface264.

The cutoff wheel186comprises a sheet-metal hub228(FIG.4). The sheet-metal hub228comprises a centering hole268, via which the cutoff wheel186can be centered on the centering collar266of the driving flange256. The sheet-metal hub228is connected and pressed to a grinding means114via a riveted joint, which is not shown in greater detail. The sheet-metal hub228comprises three slots214,216,218evenly spaced in the circumferential direction34,36, each of which comprises a wide area244,246,248produced by means of a bore hole, and a narrow area270,272,274extending in the circumferential direction36.

A part of the sheet-metal hub228is designed as a spring shackle on one end of the slot214,216,218opposite to the wide area244,246,248, which spring shackle forms a detent element190,192,194. Instead of spring shackles integrally-moulded to the sheet-metal hub228, spring-mounted driving pins could also be attached to the driving flange.

When the cutoff wheel186with its sheet-metal hub228is placed on the driving flange256, the heads of the driving pins202,204,206are inserted through the wide areas244,246,248of the slots214,216,218. The sheet-metal hub228is oriented with its centering hole268over the centering flange266. By rotating the sheet-metal hub228relative to the driving flange256against the driving direction34, the spring shackles or the detent elements190,192,194move under the heads of the driving pins202,204,206. The direction of rotation36for securing the cutoff wheel186is opposite to the driving direction34of the drive shaft54. This ensures that the cutoff wheel186does not unintentionally come loose during operation. The heads of the driving pins202,204,206glide over the lugs276of the spring shackles or the detent elements190,192,194when rotated, and displace them in the axial direction44toward the driving flange256. When the heads have passed the lugs276or an operating position of the cutoff wheel186has been reached, the spring shackles spring back partially in the axial direction38and grip behind the heads with positive engagement. A snap-in noise produced thereby can serve to ensure the operator that the sheet-metal hub228is locked in place as desired. A remaining tension or spring force of the spring shackles presses the cutoff wheel186against the bearing surface264without play in the axial direction44.

The drive torque of the electric motor is transferred from the driving flange256with positive engagement via the driving pins202,204,206and via the spring shackles or via the detent elements190,192,194to the sheet-metal hub228. A brake torque that is produced and opposes the drive torque is transferred with positive engagement from the heads of the driving pins202,204,206via the lugs276of the detent elements190,192,194to the sheet-metal hub228, and with frictional engagement from the bearing surface264to a corresponding bearing surface of the sheet-metal hub228. The magnitude of the friction force thereby depends on the surface condition of the two bearing surfaces264and a clamping force of the spring shackles, and can be adjusted accordingly via these parameters. The cutoff wheel186is reliably prevented from spinning off. So as to transfer particular high brake torques, a Velcro connection or another type of positive-engagement connection can be created between the bearing surfaces, for example.

To remove the cutoff wheel186, the cutoff wheel186is rotated in the driving direction34relative to the driving flange256so that the heads of the driving pins202,204,206glide over the lugs276of the detent elements190,192,194. When the driving pins202,204,206come to rest in the wide areas244,246,248of the slots214,216,218, the cutoff wheel186can be removed from the driving flange256in the axial direction38.

An alternative carrier device184having a corresponding cutoff wheel188is shown inFIGS. 6 and 7. Components that essentially remain the same are basically labelled with the same reference numerals in the exemplary embodiments shown. Moreover, the description of the exemplary embodiment inFIGS. 1 through 5can be referred to for the exemplary embodiment inFIGS. 6 and 7.

The carrier device184comprises a driving flange234. Three driving pins208,210,212are pressed into the driving flange234, which extend in the axial direction38over an axial bearing surface232of the driving flange234for the cutoff wheel188, and are spaced evenly in the circumferential direction34,36. Heads are integrally-moulded with the driving pins208,210,212on their ends pointing toward the cutoff wheel188. The head has a larger diameter than the remaining part of the driving pin208,210,212and forms a conical, tapering transfer surface226in the axial direction44toward the driving flange234. Recesses236are provided in the bearing surface232in the vicinity of the driving pins208,210,212.

The cutoff wheel188comprises a sheet-metal hub230(FIG.7). The sheet-metal hub230comprises a centering hole268, via which the cutoff wheel188can be centered on a centering collar266of the driving flange234. The sheet-metal hub230is connected and pressed to a grinding means144via a riveted joint, which is not shown in greater detail. The sheet-metal hub230contains three slots220,222,224evenly spaced in the circumferential direction34,36, each of which comprises a wide area238,240,242produced by means of a bore hole, and a narrow area, each of which forms a detent element196,198,200, in front of an end position250,252,254of the driving pins208,210,212.

When the cutoff wheel188with its sheet-metal hub230is placed on the driving flange234, the heads of the driving pins208,210,212are inserted through the wide areas238,240,242of the slots220,222,224. The sheet-metal hub230is oriented with its centering hole268over the centering collar266. When the sheet-metal hub230is rotated against the driving direction24relative to the driving flange234, the driving pins208,210,212move in the curved slots220,222,224. The direction of rotation36for securing the cutoff wheel188is opposite to the driving direction34of the drive shaft54. This ensures that the cutoff wheel188does not unintentionally come loose during operation.

When the sheet-metal hub230is rotated, the heads of the driving pins208,210,212glide with their conical transfer surfaces226over the narrowed areas or over the detent elements196,198,200of the slots220,222,225, each of them thereby pressing part of the sheet-metal hub230axially in the recesses236of the bearing surface232of the driving flange234provided for this in the vicinity of the slots220,222,224in the direction44of the driving flange234. When the cutoff wheel188has reached an operating position, or when the driving pins208,210,212have reached their end position250,252,254having a width slightly larger than the middle area of the slots220,222,224, the detent elements196,198,200snap into place behind the heads of the driving pins208,210,212with positive engagement. In the end positions250,252,254, the sheet-metal hub230is displaced elastically by a defined amount by the conical transfer surfaces226of the driving pins208,210,212. A remaining elastic clamping force of the sheet-metal hub230presses this against the bearing surface232. The sheet-metal hub230is secured without play in the axial direction38,44with positive engagement.

The drive torque of the electric motor is transferred from the driving flange234with positive engagement via the driving pins208,210,212at the end of the slots220,222,224to the sheet-metal hub230. A brake torque that is produced and opposes the drive torque is transferred with positive engagement from the heads of the driving pins208,210,212via the detent elements196,198,200to the sheet-metal hub230, and with frictional engagement from the bearing surface232to a corresponding bearing surface of the sheet-metal hub230. The magnitude of the friction force thereby depends on the surface condition of the two bearing surfaces232and a clamping force of the detent elements196,198,200, and can be adjusted accordingly via these parameters. The cutoff wheel186is reliably prevented from spinning off.

To remove the cutoff wheel188, the cutoff wheel188is rotated in the driving direction34relative to the driving flange234so that the heads of the driving pins208,210,212glide over the detent elements196,198,200. When the driving pins208,210,212come to rest in the wide areas238,240,242of the slots220,222,224, the cutoff wheel188can be removed from the driving flange234in the axial direction38.

FIG. 8shows a sectional view along the line VIII—VIII inFIG. 1 through acarrier device12that is an alternative to FIG.2. The carrier device12comprises a driving flange82pressed solidly to a side of a drive shaft54facing a cutoff wheel18and a driving disk56supported on the drive shaft54in such a fashion that it can be displaced axially against a coil spring20located in the center.

Three pins40are pressed into the driving flange82that extend in the axial direction38toward the cutoff wheel18over the driving flange82and that are evenly spaced in the circumferential direction34,36. Each of the pins comprises a head on its end pointing toward the cutoff wheel18that has a larger diameter compared to a remaining part of the pin40, and, on a side facing the driving flange82, a conical support surface76tapering in the axial direction44. The driving flange82forms an axial bearing surface80for the cutoff wheel18that establishes an axial position of the cutoff wheel18and in which recesses84are provided in the vicinity of the pins40. Moreover, three axial through holes104are provided in the driving flange82that are evenly spaced in the circumferential directin34,36; in fact, one through hole104each is located between two pins40in the circumferential direction.

Three bolts24are pressed in the driving disk56supported on the drive shaft54in axially displaceable fashion, which extend in the axial direction38toward the cutoff wheel18over the driving disk56and are evenly spaced in the circumferential direction34,36. The driving disk56is pressed against the driving flange82by the coil spring20in the direction38toward the cutoff wheel18. The bolts24extend through the through holes104and extend in the axial direction38over the driving flange82.

Moreover, the carrier device12comprises a release button28designed in the shape of a pot, located in the middle, on the side facing the cutoff wheel18. The release button28comprises three segments106evenly spaced in the circumferential direction34,36and extending in the axial direction44toward the axially movable driving disk56that grip through corresponding recesses108of the driving flange82and are connected to the driving disk56in the axial direction38via a circlip110secure the release button28from falling out. The release button28is inserted in displaceable fashion into a ring-shaped recess112in the driving flange82in the axial direction38,44.

The cutoff wheel18comprises a sheet-metal hub52that is solidly connected and pressed to a grinding means114via a riveted joint which is not shown in greater detail (FIG.9). The tool hub could also be produced out of another material appearing practical to one skilled in the art, such as plastic, etc. The sheet-metal hub52comprises three sequential holes46,48,50in the circumferential direction34,36, the diameter of which is slightly greater than the diameter of the bolts24. Moreover, the sheet-metal hub52comprises three slots64,66,68located in sequence in the circumferential direction34,36and extending in the circumferential direction34,36, each of which comprises a narrow area70,72,74and a wide area58,60,62produced by means of a bore hole, the diameter of which is slightly larger than the diameter of the heads of the pins40.

The sheet-metal hub52comprises a centering hole116, the diameter of which is advantageously selected so that the cutoff wheel18can also be mounted on a traditional angle grinder using a traditional mounting system with a mounting flange. A “downward compatibility” is ensured.

When mounting the cutoff wheel18, the cutoff wheel18is slid with its centering hole116onto the release button28and centered radially. The cutoff wheel18is then rotated until the pins40grip in the wide areas58,60,62of the slots64,66,68of the sheet-metal hub52provided for this. By pressing the sheet-metal hub52against the bearing surface80of the driving flange82, the bolts24in the through holes104and the driving disk56are displaced against a spring force of the coil spring20on the drive shaft54axially in the direction44opposite to the cutoff wheel18.

Rotating the sheet-metal hub52further against the driving direction34displaces the pins40in the curved narrow areas70,72,74of the slots64,66,68. The pins40thereby press with their conical support surfaces76on the edges of the slots64,66,68, and press them elastically into the recesses84of the driving flange82. The sheet-metal hub52is thereby pressed against the bearing surface80and immobilized in the axial direction38,44.

In a final operating position of the cutoff wheel18, the holes46,48,50come to rest in the sheet-metal hub52via the through holes104of the driving flange82.

The bolts24are displaced axially in the direction38of the cutoff wheel18by means of the spring force of the coil spring20, snap into place in the holes46,48,50of the sheet-metal hub52, and immobilize them with positive engagement in both circumferential directions34,36. When they snap into place, a snap-in noise audible to the operator is produced which signals to the operator that the tool is ready to use.

A drive torque of the electric motor of the angle grinder10can be transferred to the cutoff wheel18from the drive shaft54to the driving flange82with non-positive engagement, and from the driving flange82via the bolts24with positive engagement. The drive torque is transferred exclusively via the bolts24, because the slots64,66,68are designed so that the pins40do not come to rest at the narrow end70,72,74of the slots when the bolts24are snapped into place. Moreover, a brake torque occurring during and after the electric motor is switched off and that is opposed to the drive torque can be transferred with positive engagement by the driving flange82to the cutoff wheel18via the bolts24. The cutoff wheel18is reliably prevented from unintentionally coming loose. An advantageous, even distribution of forces and mass is achieved by means of the three bolts24evenly spaced in the circumferential direction34,36.

The release button28is pressed to release the cutoff wheel18from the angle grinder10. The driving disk56is thereby displaced with the bolts24via the release button28against the coil spring20in the axial direction44opposite to the cutoff wheel18, whereby the bolts24move in the axial direction44out of their locked position or out of the holes46,48,50of the sheet-metal hub52. The cutoff wheel18is then rotated in the driving direction34until the pins40come to rest in the wide areas58,60,62of the slots64,66,68and the cutoff disk18can be removed from the driving flange82in the axial direction38. After the release button28is released, the driving disk56, the bolts24, and the release button28are pushed back to their initial positions by means of the coil spring20.

An exemplary embodiment with a carrier device14that is an alternative to the exemplary embodiment inFIG. 8is shown in FIG.10.FIGS. 8 and 9can be referred to with regard for features and functions that remain the same.

The carrier device14comprises a driving flange90pressed onto the drive shaft54. A collar92is integrally-moulded to a driving flange90forming a bearing surface88for the cutoff wheel18, via which collar92the cutoff wheel18is centered radially in its state with the centering hole116mounted. Radial forces can be advantageously absorbed by the driving flange90without stressing the release button28.

In order to immobilize the cutoff wheel18, moreover, three pins42spaced evenly in sequence in the circumferential direction34,36and extending in the axial direction38over the bearing surface88are supported in the driving flange90in a fashion that allows them to be displaced in the axial direction38against one disk spring86in each case. Each of the pins42comprises a head on its end pointing toward the cutoff wheel18that has a larger diameter than a remaining portion of the pin42and has a conical transfer surface78tapering in the axial direction44on a side facing the driving flange90, and a support surface78aextending in parallel to the bearing surface88. When the heads of the pins42are inserted through the wide areas58,60,62of the slots64,66,68, rotating the sheet-metal hub52against the driving direction34causes the pins42to be displaced into the curved narrow areas70,72,74of the slots64,66,68. The pins42are therefore displaced axially over the conical transfer surfaces78against the pressure of the disk spring86in direction38until the support surfaces78aof the pins42overlap the edges of the slots64,66,68in the curved narrow areas70,72,74.

In the installed state, the disk springs86press the cutoff wheel18against the bearing surface88via the support surfaces78aof the pins42. Instead of a plurality of disk springs86, the pins can also be loaded via a common spring element, e.g., via a disk spring extending over the entire circumference and not shown in greater detail. The exemplary embodiment shown inFIG. 10having the pins42supported in axially displaceable fashion is suited in particular for thick and/or only slightly elastically deformable tool hubs.

FIGS. 11 through 18show a further exemplary embodiment having a carrier device16. The carrier device16comprises a driving flange118secured to a drive shaft—not shown in greater detail—via a thread120(FIG. 11,FIGS. 16,17, and18). The driving flange could also be designed connected to the drive shaft via a non-detachable connection, or it could be designed as an integral part with this.

The driving flange118comprises three segments122,124,126and intermediate spaces128,130,132between them located in sequence in the circumferential direction34,36and extending in the axial direction38to a cutoff wheel32(FIG.16). Each of these segments122,124,126comprises a groove134,136,138on its circumference that is closed against the driving direction34in each case via a rotary stop140,142,144and is open in the driving direction34. Moreover, the driving flange118comprises a bearing surface180that establishes an axial position of the cutoff wheel32. Moreover, the segments122,124,126form a centering collar for the cutoff wheel32, via which the cutoff wheel32can be centered.

In the installed state, a detent element26is connected to the driving flange118via three snap-in pegs146,148,150spaced around the circumference, that grip through corresponding recesses158,160,162of the driving flange118and grip radially outward behind the driving flange118(FIGS. 11,14, and15). Three locking segments152,154,156located in sequence in the circumferential direction34,36and extending radially outward are integrally-moulded to the detent element26, which also forms a release button30. A coil compression spring22is located between the driving flange118and the detent element26, against which the detent element26can be displaced relative to the driving flange118in the axial direction44opposite to the cutoff wheel32. The detent element26is thereby guided over radially outwardly-pointing bearing surfaces164,166,168between the locking segments152,154,156in radially inwardly-pointing surfaces of the segments122,124,126of the driving flange118. To prevent the detent element26from tilting and to achieve small bearing surfaces164,166,168, the bearing surfaces164,166,168are formed by projections170extending radially outward (FIG.14).

In the installed state, the locking segments152,154,156are located in the intermediate spaces128,130,132of the driving flange118and extend radially over a groove bottom of the grooves134,136,138. In an initial position before installation of the cutoff wheel12, the locking segments152,154,156of the detent element26lie in front of the grooves134,136,138, loaded by the preloaded coil compression spring22, in fact.

The cutoff wheel32comprises a ring-shaped sheet-metal hub94that is press-moulded with a grinding means114on its outer diameter and comprises tongues or spring elements172,174,176pointing radially outward on its internal diameter (FIGS. 11,12, and13). The spring elements172,174,176, in combination with the driving flange118and the release button30, serve to transfer the drive torque, to axially position the cutoff wheel32, and to secure the cutoff wheel32from spinning off when the electric motor is switched on or when the brake is applied to the drive shaft. Moreover, the spring elements, in addition to the segments122,124,126, can be used to center the cutoff wheel32to the drive shaft.

When the cutoff wheel32is installed, it is oriented on the driving flange118in such a fashion that the spring elements172,174,176on the internal diameter of the sheet-metal hub94point into the intermediate spaces128,130,132between the segments122,124,126on the driving flange118. The spring elements172,174,176of the cutoff wheel32lie on the locking segments152,154,156of the release button30. The cutoff wheel32is then pressed in the axial direction until it reaches the bearing surface180of the driving flange118. The spring elements172,174,176displace the release button30with their locking segments152,154,156against the spring force of the coil compression spring22in the direction44axially opposite to the cutoff wheel32. The locking segments152,154,156are pressed into recesses178of the driving flange118(FIG. 18) so that the spring elements172,174,176come to rest in front of the grooves134,136,138.

The cutoff wheel32is thereby centered radially via the centering collar formed by the segments122,124,126. When the cutoff wheel32is turned against the driving direction34, the spring elements172,174,176grip into the grooves134,136,138of the driving flange118. A spring-groove connection is established. The spring elements172,174,176comprise the length of the grooves134,136,138in the circumferential direction36. If the spring elements172,174,176are pushed into the grooves134,136,138completely, or if an operating position of the cutoff disk32is reached, the detent element26snaps into place with its locking segments152,154,156, wherein the coil compression spring22presses the detent element26with its locking segments152,154,156into its initial position, so that the locking segments152,154,156come to rest in front of the grooves134,136,138once more. The detent element26, with its locking segments152,154,156, immobilizes the cutoff wheel32against the driving direction34with positive engagement.

A snap-in noise that is audible to the operator is produced during the snap-in procedure that signals to the user that the snap-in procedure was completed as desired and the tool is ready to use.

The drive torque is transferred with positive engagement via the rotary stops140,142,144of the driving flange118to the spring elements172,174,176of the sheet-metal hub94or the cutoff wheel32. The cutoff wheel32is centered via the centering collar formed by the segments122,124,126of the driving flange118and is held in its axial position by means of the bearing surface180and the grooves134,136,138. Moreover, a brake torque occurring during and after the the electric motor is switched off that opposes the drive torque is transferred with positive engagement from the locking segments152,154,156and the driving flange118to the spring elements172,174,176of the cutoff wheel32.

A compensation for play is achieved in the axial direction by means of a spring element—not shown in greater detail—formed by a metal strip in the grooves134,136,138. Moreover, a compensation for play could be achieved via other spring elements appearing practical to one skilled in the art, such as via spring-loaded balls that are located in suitable locations of the driving flange and that immobilize the tool hub of the cutoff wheel without play, and/or via a slight oversizing of the spring elements of the tool hub, by means of a slightly wedge-shaped form of the grooves and the spring element of the tool hub, etc.

To release the cutoff wheel32, the release button30is pressed in the axial direction44opposite to the cutoff wheel32. The locking segments152,154,156of the release button30or the detent element26are pushed into the recesses178of the driving flange118. The cutoff wheel32can then be rotated in the driving direction34with its spring elements172,174,176out of the grooves134,136,138of the driving flange118and removed in the axial direction38. When the cutoff wheel32is removed, the release button30is pressed back into its initial position by the coil compression spring22.

An exemplary embodiment having a carrier device300that is an alternative to the exemplary embodiment inFIG. 10is shown in FIG.19. The carrier device300comprises a driving flange90that forms a bearing surface88for a cutoff wheel that is not shown in greater detail. A collar92is integrally moulded to the carrier flange90on the side facing the cutoff disk, via which the cutoff disk is centered radially with its centering hole in the installed state. Radial forces can be advantageously absorbed by the driving flange90without stressing the release button28.

A sheet-metal plate308having three integrally-moulded fastening elements306extending in the axial direction38and spaced evenly in the circumferential direction are located on a side of the driving flange90opposite to the cutoff wheel to lock the cutoff wheel in place axially. The fastening elements306are integrally-moulded to the sheet-metal plate308in a bending procedure.

During installation, the driving flange90, an undulate washer312, and the sheet-metal plate308are preassembled. The undulate washer312is thereby slid onto a collar322of the driving flange90pointing in the direction opposite to the cutoff wheel. The fastening elements306of the sheet-metal plate308, which comprise a hook-shaped extension on its exposed end with an angled surface310pointing in the circumferential direction (FIGS.19and21), are guided in the axial direction38through recesses314in the driving flange90, in fact, each of them through widened areas316of the recesses314(FIGS.19and21). By compressing and rotating the sheet-metal plate308and the driving flange90against each other, the undulate washer312is preloaded, and the sheet-metal plate308and the driving flange90are connected with positive engagement in the axial direction38,44, in fact, by the hook-shaped extensions rotating in narrow areas318of the recesses314(FIGS. 19,21, and22). The sheet-metal plate308is then supported, loaded by the undulate washer312, on the bearing surface88of the driving flange90via edges310aof the hook-shaped extensions that point axially in the direction opposite to the cutoff wheel.

After the sheet-metal plate308with the integrally-moulded fastening elements306, the undulate washer312, and the driving flange90are preassembled, a compression spring20and a driving disk304having three integrally-moulded bolts302extending in the axial direction38and spaced evenly around the circumference are slid onto a drive shaft54. The bolts302are integrally-moulded to a sheet-metal plate forming the driving disk304in a deep-drawing process (FIG.20).

The preassembled assembly consisting of the sheet-metal plate308, the undulate washer312and the driving flange90are then mounted on the drive shaft54. During installation, the bolts302are guided through recesses320integrally-moulded on the circumference of the sheet-metal plate308and through through holes104in the driving flange90and grip through the through holes104in the installed state. The sheet-metal plate308and the driving flange90are secured via the bolts302against rotating in relation to each other.

The driving flange90is pressed onto the drive shaft54and then secured with a retaininer ring not shown in further detail. In addition to a compression connection, other connections appearing practical to one skilled in the art are also feasible, such as a threaded connection, etc.

When, during mounting of a cutoff wheel18(refer to FIGS.8and10), the hook-shaped extensions of the fastening elements306are guided through the wide areas58,60,62of the slots64,66,68of the sheet-metal hub52(FIG.19), rotating the sheet-metal hub52against the driving direction34causes the hook-shaped extensions to be pushed into the curved, narrow areas70,72,74of the slots64,66,68of the sheet-metal hub52. In doing so, the sheet-metal plate308with the fastening elements306is displaced axially via the angled surfaces310against the pressure of the undulate washer312in direction38until the edges310a of the hook-shaped extensions come to rest in curved, narrow areas70,72,74laterally next to the slots64,66,68of the sheet-metal hub53. In the installed state, the undulate washer312presses the cutoff wheel18against the bearing surface88via the edges310aof the hook-shaped extensions.

As an alternative, the fastening elements and the slots can be designed rotated by 180° in the sheet-metal hub, so that the mounting direction reverses, and the sheet-metal hub is rotated in the driving direction during mounting. If the fastening elements are designed rotated by 180°, an angled surface of a lower front edge of the fastening element leads during operation, so that injuries by a front edge can be prevented.