# Patent

## Title
Hand-held power tool system

## Abstract

A hand-held power tool system has a hand-held power tool, a guard unit, and a guard anti-rotation lock unit preventing rotation between the guard unit and the hand-held power tool during breakdown of a tool of the hand-held power tool and configured to prevent rotation between the guard unit and the hand-held power tool at a same time as the guard unit is being attached to the hand-held power unit when the guard unit is in a working position, the guard anti-rotation lock unit is at least partially located on a closing unit which includes a clamping band and a pivotable lever, and the anti-rotation lock unit includes at least one anti-rotation lock element provided on the lever.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2006 053 305.4 filed on Nov. 13, 2006. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).
This application is also a continuation of U.S. patent application Ser. No. 12/293,850 filed on Sep. 22, 2008, which is also incorporated herein by reference and which also constitutes a basis for claiming the priority of this application under 35 U.S.C. 119(a)-(d).


BACKGROUND OF THE INVENTION
The present invention relates to a hand-held power tool system.
Publication EP 812 657 A1 makes known an angle grinder with an adjustable guard. In that case, the guard is adjustable in a rotating manner on a connection piece of a flange of the angle grinder, and is supported such that it may be detachably attached using a single form-fit locking means. The spindle of the angle grinder passes through the center of the flange. A cutting disk and/or grinding disk are/is installed on the free end of the spindle in a clampable, rotationally drivable manner for cutting and machining work pieces, which are partially enclosed by the guard. The guard must be positioned in a rotationally adjustable manner on the hand-held power tool such that the region of the grinding disk that faces the user is enclosed by the guard. At the same time, a region of the grinding disk that points away from the user extends past the flange, radially relative to the work piece engagement.
SUMMARY OF THE INVENTION
The present invention is directed to a hand-held power tool system with a hand-held power tool, in particular an angle grinder, a guard unit, and a guard anti-rotation lock unit, which is provided to prevent rotation between the guard unit and the hand-held power tool during breakdown of a tool.
It is provided that the guard anti-rotation lock unit is provided to prevent rotation between the guard unit and the hand-held power tool at the same time as the guard unit is being attached to the hand-held power tool when the guard unit is in a working position. In this context, “provided” is intended to mean, in particular, specially equipped and/or designed. In addition, the expression “working position of the guard unit” refers, in particular, to a position of the guard unit in which the guard unit is non-rotatably located on the hand-held power tool during regular working operation of the hand-held power tool, and a guard of the guard unit ensures advantageous protection for an operator against contact with a tool, in particular a disk-shaped, rotatably drivable tool, and/or from machining residue that is slung in the direction of the operator. In addition, a “breakdown of the tool” is intended to mean, in particular, a tool that bursts during operation of the hand-held power tool, in which case individual tool parts may be slung outwardly due to rotation of the tool.
Due to the inventive design of the hand-held power tool system, it is possible to protect an operator of the hand-held power tool—in an effective and, in particular, reliable manner—from a tool that rotates during operation of the hand-held power tool, and, in particular, from pieces of the tool that are slung in the direction of the operator if the tool becomes damaged, e.g., if the tool should burst. Advantageously, a sizing of the guard anti-rotation lock unit is designed to absorb forces that occur when the tool becomes damaged, these forces being transferred from pieces of the burst tool that strike the guard unit to the guard unit itself, when the guard unit is in an anti-rotation lock position with the hand-held power tool.
Advantageously, a position of the guard unit during breakdown of the tool is preferably maintained via the guard anti-rotation lock unit and an operation of the guard unit. In addition, in particular, a protective position and/or an anti-rotation lock position of the guard unit is designed as the working position of the guard unit, thereby making it possible for the anti-rotation lock position to be attained by an operator of the hand-held power tool system using a simple design. Particularly advantageously, the guard anti-rotation lock element is located, at least partially, on guard and/or a closing unit of the guard unit. A “closing unit” refers, in particular, to a unit that is preferably provided to attach the guard unit to the hand-held power tool, and that includes at least one closing element, e.g., a clamping band, a screw, a closing lever, etc., it being possible to attach the guard unit to the hand-held power tool using the closing unit in a form-fit and/or non-positive manner. In addition, “located” is intended to mean, in particular, that the guard anti-rotation lock unit and the guard and/or the closing unit include a common installation unit and that they may be installed in an operating position on the hand-held power tool in the same installation procedure.
A particularly stable anti-rotation lock between the guard unit and the hand-held power tool may be attained using a simple design when the guard anti-rotation lock includes a non-positive connection unit and/or form-fit connection unit, which are/is provided to establish a non-positive and/or form-fit connection between the guard unit and the hand-held power tool.
It is also provided that the guard anti-rotation lock unit includes at least one anti-rotation lock element located on the guard unit, and an anti-rotation lock element located on the hand-held power tool, which are located at least partially in an anti-rotation lock position when the guard unit is in the working position, thereby making it advantageously possible to realize an effective anti-rotation lock when the guard unit is in a working position, thereby providing a high standard of safety for an operator.
If, in addition, the anti-rotation lock element is formed at least partially by a detent element that is provided to block a motion of the guard unit in at least one direction, it is advantageously possible to prevent rotation of the guard unit—in particular if a tool should burst—and to make it easier, at least partially, for an operator of the hand-held power tool system to change the position of the guard unit. Preferably, a blocking direction of the detent element corresponds to a rotational direction of a tool, thereby making it possible for an advantageous anti-rotation lock to be attained if the tool should break down.
Furthermore, additional components, installation space, assembly effort and costs may be advantageously saved when the anti-rotation lock element is designed as a single piece with a closing unit and/or a guard of the guard unit. The term “single piece” is intended to mean, in particular, one piece, cast, and/or designed as one component.
When the closing unit includes at least one closing element on which the anti-rotation lock element is located, it is possible to provide an operator with an anti-rotation lock of the guard unit that is easy to install.
It is further provided that the guard anti-rotation lock unit include at least one anti-rotation lock element which is provided on a pivotable lever of the closing unit.
A particularly easy means for attaching and removing the guard unit to/from the hand-held power tool may be advantageously attained when the anti-rotation lock element is movably supported on a closing unit and/or a guard of the guard unit. The anti-rotation lock element is preferably located such that it may be moved manually by an operator to release the anti-rotation lock position into an unlocked position. This may be attained in a particularly advantageous manner when the anti-rotation lock element is supported on the closing unit and/or on the guard such that it may move at least partially around a swivel axis.
In an alternative embodiment of the present invention, it is provided that the guard anti-rotation lock unit includes at least one lever element on which the anti-rotation lock element is at least partially located, by way of which the anti-rotation lock element may be advantageously moved into an anti-rotation lock position and/or into an inactive position using the lever element. Particularly advantageously, the lever element is rotatably supported on the hand-held power tool and/or the guard unit.
It is further provided that the guard anti-rotation lock unit includes at least one moving element that moves the anti-rotation lock element into an anti-rotation lock position when the guard unit reaches its working position, thereby resulting in an at least partially automatic fixing mechanism or moving mechanism that is independent of an operator in order to attain an anti-rotation lock position of the anti-rotation lock element and result in in a high safety standard for the operator independently of a manual actuation by the operator of the guard anti-rotation lock unit. The moving element is advantageously designed as a spring element and/or further moving elements that appear reasonable to one skilled in the technical art, e.g., a moving element designed as a magnet.
In an advantageous refinement of the present invention, it is provided that the guard anti-rotation lock unit includes at least one release element, which is provided to move the anti-rotation lock element out of the anti-rotation lock position. As a result, a means for advantageously removing the guard unit after a working process or after operation of the hand-held machine system may be attained. The release element is advantageously supported on the guard unit such that it is at least partially movable—the release element being preloaded in particular with spring loading in the anti-rotation lock position—thereby making it possible to install the release element in a compact manner and to advantageously secure the anti-rotation lock element in the anti-rotation lock position.
Furthermore, additional components, installation space, assembly effort and costs may be advantageously saved when the release element is designed at least partially as a single piece with the locking unit.
Advantageously, the hand-held power tool includes a receiving unit for accommodating a tool, on which the anti-rotation lock element is located, thereby making it possible, in particular, to provide a space-saving, compact guard anti-rotation lock unit by the fact that the anti-rotation lock element of the hand-held power tool is located on a component that is preferably located such that it has direct contact with the guard unit when the guard unit is in a working position.
It is also provided that the anti-rotation lock element is movably located on the receiving unit, by way of which a particularly easy means for attaching and removing the guard unit to the hand-held power tool may be advantageously attained.
Preferably, additional components, installation space, assembly effort and costs may also be saved when the anti-rotation lock element located on the receiving unit is designed at least partially as a single piece with the receiving unit.
When the guard anti-rotation lock unit includes at least two anti-rotation lock elements, which are located one after the other in the circumferential direction on the guard unit, and/or at least two anti-rotation lock elements, which are located one after the other in a circumferential direction on the hand-held power tool, in particular on its receiving unit, it is possible to attain a reusable form-fit and/or non-positive connection between the guard unit and the hand-held power tool, and/or the guard unit may be installed on the hand-held power tool in different positions along the circumferential direction in a non-rotating manner, in particular if a tool should burst. The term “circumferential direction” is intended to mean, in particular, a circumferential direction of the guard unit, which is oriented essentially parallel to a direction of rotation of the tool when the guard unit is in an installed state.
Particularly advantageously, the present invention includes a hand-held power tool for a rotating, preferably disk-shaped tool, with a machine housing that includes a flange and/or a machine neck, on which a guard—that is composed of sheet metal in particular—is detachably clampable in order to cover the tool. The guard includes a guard body, which is composed of a circular, disk-shaped piece, in particular with an outer edge located at a right angle thereto, and with a central, circular recess, on the edge of which a guard connection piece and/or collar is formed and that includes an annular clamping band that may be tightened using a clamping means. An anti-rotation lock that acts between the machine neck and the guard is located between the guard and the machine neck and is designed as a profiled structure. The guard may be repeatedly coupled via the clamping band and/or the clamping means in its clamping position in a form-fit and/or non-positive manner with the machine neck, and is therefore capable of being fixed in a non-rotatable position and, to attain a release position, may be disengaged from the form-fit and/or non-positive connection, so that the guard may then be adjusted in a rotational manner.
Further advantages result from the description of the drawing, below. Exemplary embodiments of the present invention are shown in the drawing. The drawing, the description, and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exploded view of an inventive hand-held power tool system,
FIGS. 2a, 2b show the guard anti-rotation lock unit in FIG. 1 with an anti-rotation lock element that is movably supported on the clamping band, in a schematic partial view from above, in a first variant (FIG. 2a) and in a second variant (FIG. 2b),
FIG. 3 shows the guard anti-rotation lock unit with an alternative anti-rotation lock element that is movably supported on the clamping band, in a schematic cross-sectional view,
FIGS. 4a and 4b show a guard anti-rotation lock unit with an anti-rotation lock element designed as a single piece with a clamping band, and with a positioning unit, in a schematic partial view from above (FIG. 4a) and in a schematic side view (FIG. 4b),
FIG. 5 shows a guard anti-rotation lock unit with an anti-rotation lock element designed as a single piece with a clamping band, in the region of a closing element, in a schematic partial view,
FIG. 6 shows the guard anti-rotation lock unit of an anti-rotation lock element designed as a single piece with a closing element, in a schematic partial view,
FIGS. 7a, 7b, 7c show the hand-held power tool system with a positioning unit and the guard anti-rotation lock unit, and a closing unit designed as an alternative to that shown in FIG. 6, and in a schematic partial view (FIG. 7a), in a side view (FIG. 7b), and in a further alternative embodiment, in a side view (FIG. 7c),
FIGS. 8a, 8b show a guard anti-rotation lock unit with an anti-rotation lock element that is movably supported on a closing element, in a schematic side view (FIG. 8a), and in a perspective view (FIG. 8b),
FIG. 9 shows a guard anti-rotation lock unit with an anti-rotation lock element that is movably supported on a receiving unit, in an exploded view,
FIG. 10 shows a guard anti-rotation lock unit, which is located as a single piece on a guard of a guard unit, in a perspective view,
FIG. 11 shows a guard anti-rotation lock unit with anti-rotation lock elements designed as a single piece with a guard, which is held in an anti-rotation lock position using a spring element, in a schematic partial view,
FIG. 12 shows a guard anti-rotation lock unit with an anti-rotation lock that is based on a non-positive connection, in an exploded view,
FIGS. 13a and 13b show a guard anti-rotation lock unit with a release element located on the guard, in a schematic cross-sectional view (FIG. 13a), and in a perspective partial view (FIG. 13b),
FIG. 14 shows a guard anti-rotation lock unit with an anti-rotation lock element and a release element located on the guard, in a schematic top view, and
FIG. 15 shows a guard anti-rotation lock unit—that is an alternative to that shown in FIG. 14—with an anti-rotation lock element and a release element located on the guard, in a schematic top view.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a hand-held power tool system 10a with a hand-held power tool 12a designed as an angle grinder, and with a guard unit 14a and a guard anti-rotation lock unit 16a. To accommodate guard unit 14a and/or a tool 18a, which is designed as a cutting disk, hand-held power tool 12a includes a receiving unit 60a, which is screwed together with hand-held power tool housing 66a of hand-held power tool 12a. A drive shaft 70a extends out of receiving unit 60a on a side 68a facing away from hand-held power tool housing 66a. Drive shaft 70a is connectable at its free end 72a with disk-shaped tool 18a and is rotationally drivable around an axis 74a. Guard unit 14a includes a guard 22a and a closing unit 20a, on which guard anti-rotation lock unit 16a is located.
Guard 22a extends around an angular range of tool 18a of approximately 180° and, to this end, includes a semi-disk shaped guard body 76a and a guard edge 78a, which is initially oriented perpendicularly to semi-disk shaped body 76a and is finally oriented parallel to semi-disk shaped guard body 76a, inwardly in a radial direction 80a. Guard anti-rotation lock unit 16a is provided to prevent rotation between guard unit 14a and hand-held power tool 12a or receiving unit 60a during breakdown of tool 18a, e.g., if tool 18a should burst. The anti-rotation lock between guard unit 14a and hand-held power tool 12a takes place at the same time as guard unit 14a is attached to hand-held power tool 12a, when guard unit 14a is in a working position.
Guard unit 22a also includes a guard collar 82a, which is oriented essentially perpendicularly to semi-disk shaped guard body 76a (FIGS. 1, 2a, and 2b). Guard collar 82a is enclosed outwardly in radial direction 80a by a clamping band 84a of closing unit 20a. Guard collar 82a and clamping band 84a are interconnected via a welded connection. Guard collar 82a—together with clamping band 84a—is provided to attach guard unit 14a to hand-held power tool 12a and/or to receiving unit 60a, which includes a cylindrical receiving flange 86a for this purpose. Along a circumferential direction 62a, 64a of clamping band 84a, clamping band 84a includes two end regions 88a, 90a in a region that faces away from guard 22a and extends outwardly in radial direction 80a. End regions 88a, 90a each include a recess 92a, through which a clamping element 46a—designed as a clamping screw—of closing unit 20a extends. The clamping screw may be fastened in recesses 92a of clamping band 84a using a nut 94a. Guard 22a is attached in a working position to receiving unit 60a and/or on receiving flange 86a via closing unit 20a using a frictional connection between guard collar 82a and clamping band 84a and receiving flange 86a, so that guard unit 14a is positioned in a non-rotatable manner during regular operation of hand-held power tool 10a. In an alternative design of the closing unit, it is basically feasible to use—instead of the clamping screw—further closing elements 46a, e.g., a clamping lever and/or form-fit elements, etc.
Guard anti-rotation lock unit 16a prevents guard unit 14a from accidentally rotating if tool 18a should become damaged, in particular if tool 18a should burst. To this end, guard anti-rotation lock unit 16a includes a form-fit unit 26a, which is provided to establish a form-fit connection between guard unit 14a and receiving flange 86a of hand-held power tool 12a, a form-fit connection being established at the same time that guard unit 14a is attached to receiving flange 86a in a working position. To establish the form-fit connection, form-fit unit 26a and/or guard anti-rotation lock unit 16a include three anti-rotation lock elements 28a, 30a, 32a—each of which is designed as a form-fit element, and which are located on clamping band 84a of closing unit 20a—and several anti-rotation lock elements 34a, 36a formed by form-fit elements, and which are designed as a single piece with receiving unit 60a. Anti-rotation lock elements 34a, 36a located on receiving unit 60a are designed as detent recesses, and they are located one after the other in circumferential direction 62a, 64a around receiving flange 60a. Anti-rotation lock elements 34a, 36a are designed open in a direction 96a that extends away from receiving unit 60a in the direction of tool 18a and parallel to axis 74a, and which are located on a main element 98a of receiving unit 60a, which is oriented essentially perpendicularly to axis 74a. The location of anti-rotation lock elements 34a, 36a makes it possible to attach guard unit 14a to hand-held power tool 12a in different working positions in circumferential direction 62a, 64a. 
The three anti-rotation lock elements 28a, 30a, 32a of guard unit 14a are located one after the other in circumferential direction 62a, 64a, and are designed as detent elements 38a, 40a, 42a, which block a motion of guard unit 14a in one direction, when guard unit 14a is in an installed state (FIG. 2a). A blocking direction is a rotational direction of tool 18a that ensures that, if tool 18a should burst, guard unit 14a remains attached in its protective position. To this end, detent elements 38a, 40a, 42a are cut at an angle and have an essentially triangular cross-sectional area, so that, when a fastening means and/or the clamping screw are/is loosened, guard 22a may be rotated in a direction that is opposite to the rotational direction of tool 18a during operation of hand-held power tool 12a (FIG. 2a). As an alternative, anti-rotation lock elements 28a, 30a, 32a in FIG. 2b are provided with an essentially rectangular cross-sectional area that serves to prevent guard 22a from rotating in either direction of circumferential direction 62a, 64a. 
Anti-rotation lock elements 28a, 30a, 32a are movably supported on clamping band 84a. To this end, guard anti-rotation lock unit 16a includes a lever element 52a that is located on clamping band 84a such that it may swivel around swivel axis 50a. When guard unit 14a is installed on hand-held power tool 12a, swivel axis 50a of lever element 52a is oriented essentially perpendicular to axis 74a and extends away from axis 74a in a radial direction 80a. Anti-rotation lock elements 28a, 30a, 32a are located on an end 100a of lever element 52a facing away from swivel axis 50a and extend in the manner of projections along a swivel direction 102a around swivel axis 50a on lever element 52a. When guard unit 14a is in a working position, anti-rotation lock elements 28a, 30a, 32a are located on a side of lever element 52a facing anti-rotation lock elements 34a, 36a. 
Guard anti-rotation lock unit 16a also includes a moving element 54a, which is designed as a spring element 56a and moves lever element 52a and/or anti-rotation lock elements 28a, 30a, 32a into an anti-rotation lock position when guard unit 14a reaches a working position, during installation on hand-held power tool 12a. As a result, anti-rotation lock elements 28a, 30a, 32a are always in the anti-rotation lock position as soon as guard unit 14a is installed in the working position. Spring element 56a bears against a support element 104a of clamping band 84a. Support element 104a is located along axis 74a on a region 106a facing away from anti-rotation lock elements 28a, 30a, 32a, and a spring force of lever element 52a presses along axis 74a in a direction 108a facing away from tool 18a. To release the anti-rotation lock position of anti-rotation lock elements 28a, 30a, 32a, lever element 52a includes a release element 58a, which is designed as a tab, and which is located on end 100a of lever element 52a facing away from swivel axis 50a and extends outwardly on lever element 52a along radial direction 80a, so that an operator may move lever element 52a—using the tab—along with anti-rotation lock elements 28a, 30a, 32a, out of the anti-rotation lock position along swivel direction 102a. It is also feasible, in principle, for closing unit 20a to be closable only when anti-rotation lock elements 28a, 30a, 32a are located in an anti-rotation lock position. To remove and/or change the position of guard unit 14a in circumferential direction 62a, 64a, closing unit 20a must be released and, if rotation is locked in both directions, guard anti-rotation lock unit 16a must also be moved out of its anti-rotation lock position, so that anti-rotation lock elements 28a, 30a, 32a are disengaged from recesses in receiving unit 60a and guard unit 14a may rotate and/or be removed relative to hand-held power tool 12a. 
Hand-held power tool system 10a also includes a coding device 110a, which is provided to prevent tools 18a and/or tools 18a together with guard unit 14a from being installed on unsuitable hand-held power tools 12a. To this end, clamping band 84a includes a coding element 112a of coding device 110a, which is designed as a single piece with clamping band 84a. Coding device 112a is designed as a pressed-out region that extends inwardly in radial direction 80a and has a rectangular shape. Correspondingly, receiving flange 86a includes a coding element 114a of coding device 110a, which is designed as a recess into which coding means 112a of clamping band 84a may be inserted when guard unit 14a is installed on hand-held power tool 12a. After guard unit 14a has been inserted onto receiving unit 60a, guard unit 14a may be rotated into a working position. To this end, receiving flange 86a includes a groove 116a that extends in circumferential direction 62a, 64a, in which coding element 112a is guided when guard unit 14a is rotated into the working position.
Alternative exemplary embodiments are shown in FIGS. 3 through 15. Components, features, and functions that are essentially the same are labelled with the same reference numerals. To distinguish the exemplary embodiments from each other, the reference numerals of the exemplary embodiments are appended with the letters a through n. The description below is essentially limited to the differences from the exemplary embodiment in FIGS. 1 and 2. With regard for the components, features, and functions that remain the same, reference is made to the description of the exemplary embodiment in FIGS. 1 and 2.
FIG. 3 shows a hand-held power tool system 10b in a partial cross section with a receiving unit 60b of a hand-held power tool 12b, and with a clamping band 84b of a guard unit 14b, and a guard anti-rotation lock unit 16b. Guard anti-rotation lock unit 16b is provided to prevent rotation between guard unit 14b and hand-held power tool 12b at the same as guard unit 14b reaches a working position during installation. To this end, guard anti-rotation lock unit 16b includes an anti-rotation lock element 28b located on clamping band 84b of a closing unit 20b, and several anti-rotation lock elements 34b, 36b located on receiving unit 60b. Anti-rotation lock elements 34b, 36b located on receiving unit 60b are designed as recesses, which are located one after the other in a circumferential direction 62b, 64b on a receiving flange 86b of receiving unit 60b. The recesses extend radially inwardly from a radially outwardly oriented surface 118b of receiving flange 86b. Anti-rotation lock element 28b located on closing unit 20b is located on a lever element 52b of guard anti-rotation lock unit 16b. Lever element 52b is swivelably supported on clamping band 84b. Swivel axis 50b of lever element 52b is oriented essentially perpendicularly to a circumferential direction 62b, 64b of clamping band 84b. To fix lever element 52b together with anti-rotation lock element 28b in an anti-rotation lock position, lever element 52b bears against clamping band 84b via a moving element 54b designed as a spring element 56b. Spring element 56b is designed as a tension spring that is located in radial direction 80b between clamping band 84b and an inward—in radial direction 80b—surface of lever element 52b. Lever element 52b, together with anti-rotation lock element 28b, is moved and/or pulled inwardly by spring element 56b around swivel axis 50b, and it is brought into an anti-rotation lock position, i.e., in engagement with anti-rotation lock elements 34b, 36b of receiving flange. Clamping band 84b also includes a recess 122b, through which anti-rotation lock element 28b engages with receiving flange 86b in an anti-rotation lock position. On an end 120b facing away from anti-rotation lock element 28b, lever element 52b includes a release element 58b designed as a tab, via which lever element 52b may be moved by an operator from its anti-rotation lock position against a spring force of spring element 56b. An operator may release a clamping closing element 46b, which is designed as a clamping screw, only after lever element 52b has been moved out of its anti-rotation lock position.
FIG. 4a shows a hand-held power tool system 10c with a guard anti-rotation lock unit 16c, as a partial cross-section, with an anti-rotation lock element 28c of a guard unit 14c whose design is an alternative to that shown in FIG. 3. Guard anti-rotation lock unit 16c is provided to prevent rotation between guard unit 14c and a not-shown hand-held power tool at the same as guard unit 14c reaches a working position during installation. Anti-rotation lock element 28c is designed as a hook-shaped detent element 38c. In addition, detent element 38c is designed as a single piece with a clamping band 84c of a closing unit 20c. Detent element 38c of clamping band 84c is located such that it is bent inwardly. Detent element 38c therefore prevents rotation in a manner analogous to that described with reference to FIG. 2a and enables rotation in a direction opposite to a rotational direction of the tool when closing element 46c—which is designed as a clamping screw—of closing unit 20c is loosened.
To make it easier for an operator to attach guard unit 14c and/or to change the position of installed guard unit 14c on a receiving flange, hand-held power tool system 10c includes a positioning device 124c. Guard unit 14c includes a positioning element 126c of positioning device 124c, which is designed as a single piece with clamping band 84c (FIGS. 4a and 4b). Positioning element 126c is located in an edge region 128c of clamping band 84a. When guard unit 14c is installed, edge region 128c faces away from the tool. Positioning element 126c is designed as a segment in circumferential direction 62c, 64c. Positioning element 126c is punched out of clamping band 84c along two sides 130c, 132c that face clamping band 84a, and it is located in an end region 134c in circumferential direction 62c, 64c on clamping band 84c (FIG. 4b). On a free end 136c in circumferential direction 62c, 64c, positioning element 126c includes a pressed-out region that extends inwardly in radial direction 80c and has a contour that is essentially identical in shape to a contour of a not-shown positioning element of a receiving flange.
FIG. 5 shows a hand-held power tool system 10d with a guard anti-rotation lock unit 16d in a partial cross-sectional view. Guard anti-rotation lock unit 16d is provided to prevent rotation between a guard unit 14d and a hand-held power tool 12d—which is not shown in detail—at the same time as guard unit 14d reaches a working position during installation. Guard anti-rotation lock unit 16d differs from the exemplary embodiment shown in FIGS. 4a and 4b in that an anti-rotation lock element 28d of guard anti-rotation lock unit 16d is located in an end region 90d—located in circumferential direction 62d, 64d—of a clamping band 84d of a closing unit 20d. Anti-rotation lock element 28d is designed as a single piece with clamping band 84d and is bent inwardly relative to clamping band 84d. Guard anti-rotation lock unit 16d also includes several anti-rotation lock elements 34d, 36d designed as a detent recess in a receiving unit 60d of hand-held power tool 12d. Guard anti-rotation lock unit 16d functions in a manner analogous to that described with reference to FIGS. 2a, 4a, and 4b. Closing unit 20d also includes a closing element 46d, 48d on each of the end regions 88d, 90d of clamping band 84d, along circumferential direction 62d, 64d. Closing elements 46d, 48d are designed as a screw and a closing lever. The screw connects one of the end regions 88d of clamping band 84d with the clamping lever located on further end region 90d. The screw is rotatably supported at end region 88d, and it extends in circumferential direction 64d away from end region 88d in the direction toward the closing lever to a bearing point and/or a rotation axis 138d of the closing lever with end region 90d. A guard is attached in a working position via closing unit 20d on receiving unit 60d and/or on receiving flange 86d of receiving unit 60d via a frictional connection between a guard collar and/or clamping band 84d and receiving flange 86d. In addition, an operator may adjust an effective fastening force using the screw when fastening between guard unit 14d and receiving flange 86f. 
FIG. 6 shows a partial cross-sectional view of a hand-held power tool system 10e with a guard anti-rotation lock unit 16e. Guard anti-rotation lock unit 16d is provided to prevent rotation between a guard unit 14d and a hand-held power tool 12e not shown in detail at the same time as guard unit 14e reaches a working position during installation, and, to this end, includes an anti-rotation lock element 28e designed as a detent cam, which is designed as a single piece with a closing element 46e of a closing unit 20e. Closing unit 20e is designed as described with reference to FIG. 5, with anti-rotation lock element 28e being located on a clamping lever and extending—when closing unit 20e is in a closed state—inwardly in a radial direction 80e. When anti-rotation lock element 28e is located in an anti-rotation lock position and/or when guard unit 14e is installed in a working position on hand-held power tool 12e, anti-rotation lock element 28e extends into one of several anti-rotation lock elements 34e, 36e designed as recesses, which are located in a receiving flange 86e of a receiving unit 60e as described with reference to FIG. 3. Clamping band 84e also includes a recess 122e, through which anti-rotation lock element 28e extends to attain an anti-rotation lock position.
FIG. 7a shows a partial cross-sectional view of a hand-held power tool system 10f with a guard anti-rotation lock unit 16f. Guard anti-rotation lock unit 16f is provided to prevent rotation between a guard unit 14f and a hand-held power tool 12f not shown in detail at the same time as guard unit 14f reaches a working position during installation, and, to this end, includes an anti-rotation lock element 28f designed as a detent cam, which is designed as a single piece with a closing element 46f of a closing unit 20f. Closing element 46f is designed as a clamping lever, which is rotatably supported at an end region 88f—designed as an eyelet—of a clamping band 84f. The clamping lever includes a recess 140f, through which a further end region 90f of clamping band 84f extends. End region 90f has a contour that increases continually and outwardly, as viewed from clamping band 84f, so that, when closing unit 20f is closed, a clamping band diameter is reduced and an effective non-positive connection may be established between guard unit 14f and a receiving unit 60f. A design of clamping band 84f and receiving unit 60f to attain an anti-rotation lock position is similar to that described with reference to FIG. 6. Hand-held power tool system 10f shown in FIGS. 7a and 7b also includes a positioning device 124f, which is designed as described with reference to FIGS. 4a and 4b. 
FIG. 7c shows an embodiment of a positioning device 124f that is an alternative to the design shown in FIGS. 7a and 7b. A positioning element 126f extends on clamping band 84f perpendicularly to a circumferential direction 62f, 64f of clamping band 84f and faces away from a tool when guard unit 14f is in an installed state. For locking into position, positioning elements 142f of positioning device 124f that are designed as grooves are located on receiving unit 60f. Positioning elements 142f are located one after the other in a circumferential direction 62f, 64f around a receiving flange 86f on a main element 98f of receiving unit 60f. 
FIGS. 8a and 8b show a partial cross-sectional view of a hand-held power tool system 10g with a guard anti-rotation lock unit 16g. Guard anti-rotation lock unit 16g is provided to prevent rotation between a guard unit 14g and a hand-held power tool 12g not shown in detail at the same time as guard unit 14g reaches a working position during installation, and, to this end, includes an anti-rotation lock element 28g designed as a detent cam, which is movably supported on a closing element 46g of a closing unit 20g. To this end, anti-rotation lock element 28g includes a recess 144g, through which closing element 46g extends. Closing element 46g is designed as a clamping screw, similar to that shown in FIG. 1. Motion in an anti-rotation lock position takes place when a guard unit 14g is attached in a working position in that anti-rotation lock element 28g is moved into the anti-rotation lock position via a frictional connection with the clamping screw (FIG. 8b). As an alternative, a form-fit connection between the clamping screw and anti-rotation lock element 28g is also feasible. In addition, a receiving flange 86g includes several anti-rotation lock elements 34g designed as recesses, only one of which is shown in FIG. 8a. The recesses are located in a receiving flange 86g along a circumferential direction 62g, 64g, on after the other, in an edge region 146g located outwardly in radial direction 80g. 
FIG. 9 shows a hand-held power tool system 10h with a guard anti-rotation lock unit 16h, a receiving unit 60h, and a guard unit 14h. Guard anti-rotation lock unit 16h is provided to prevent rotation between a guard unit 14h and a hand-held power tool 12h at the same time as guard unit 14h reaches a working position during installation, and, to this end, includes an anti-rotation lock element 34h, which is movably supported on receiving unit 60h. Anti-rotation lock element 34h is located on a main element 98h of receiving unit 60h and extends outwardly away from a receiving flange 86h in a radial direction 80h. To ensure that guard unit 14h remains in an anti-rotation lock position on receiving flange 86h when in a working position, anti-rotation lock element 34h is held in an anti-rotation lock position by a not-shown spring element. Moreover, anti-rotation lock element 34h is designed as a single piece with a lever element 52h, with which an operator may manually release anti-rotation lock element 34h from the anti-rotation lock position. A clamping band 84h of a closing unit 20h also includes several anti-rotation lock elements 28h, 30h designed as recesses, which are located one after the other in a circumferential direction 62h, 64h on clamping band 84h. When guard unit 14h is in an installed state, the recesses are located in an edge region 128h of clamping band 84h that faces main element 98h. 
FIG. 10 shows a hand-held power tool system 10i with a guard anti-rotation lock unit 16i, a receiving unit 60i—which is shown only partially—and a guard unit 14i. Guard anti-rotation lock unit 16i is provided to prevent rotation between a guard unit 14i and a hand-held power tool at the same time as guard unit 14i reaches a working position during installation, and, to this end, includes three anti-rotation lock elements 28i, 30i, 32i, which are designed as one piece with a guard 22i of guard unit 14i. The three anti-rotation lock elements 28i, 30i, 32i of guard unit 14i are designed as toothing, and they are located one after the other in circumferential direction 62i, 64i. The toothing is located on an edge region 148i of a guard body 76i of guard 22i that faces guard collar 82i, and extend away from guard 22i inwardly in radial direction 80i within a plane of guard body 76i, thereby being oriented essentially perpendicularly to a circumferential direction 62i, 64i of guard collar 82i. The toothing is formed as a single piece with guard 22i using a stamping-bending process. In addition, a receiving flange 86i of the hand-held power tool includes several anti-rotation lock elements 34i, 36i, which are designed as form-fit elements and are designed as a single piece with receiving flange 86i. Anti-rotation lock elements 34i, 36i located on receiving flange 86i form a toothing that extends in the circumferential direction. Anti-rotation lock elements 34i, 36i are located on a side 68i of receiving flange 86i in an outer—in radial direction 80i—edge region 152i. Side 68i faces a tool during operation of the hand-held power tool. As soon as guard unit 14i is located in a working position during installation on the hand-held power tool, anti-rotation lock elements 28i, 30i, 32i, 34i, 36i also engage with each other and/or are located in an anti-rotation lock position, and guard 22i is secured against accidentally rotating if a tool should burst during operation. Anti-rotation lock elements 28i, 30i, 32i of guard 22i engage in anti-rotation lock elements 34i, 36i during a procedure of inserting guard unit 14i on receiving unit 60i in a direction 108i of a hand-held power tool housing.
FIG. 11 shows a hand-held power tool system 10j with a guard anti-rotation lock unit 16j, a receiving unit 60j, and a guard unit 14j. Guard anti-rotation lock unit 16j includes a form-fit unit 26j, which is provided to prevent guard 22j from rotating on a hand-held power tool at the same time as guard unit 14j is being attached to the hand-held power tool. Several anti-rotation lock elements 28j are located on a guard collar 82j of guard 22j of guard unit 14j, which extend away from guard collar 82j in a direction 150j facing away from guard 22j. Only one of the anti-rotation lock elements 28j is shown. In an alternative embodiment of the present invention, anti-rotation lock elements 28j may basically also be located on clamping band 84j, instead of on guard collar 82j. Anti-rotation lock elements 28j are designed as single pieces with guard collar 82j and are located one after the other in a circumferential direction on guard collar 82j. Receiving unit 60j also includes several anti-rotation lock elements 34j, which are designed as single pieces with receiving unit 60j. Anti-rotation lock elements 34j are designed as recesses and are located one after the other in the circumferential direction around a receiving flange 86j on a main element 98j of receiving unit 60j. To prevent the anti-rotation lock position of guard 22j from accidentally coming loose from the hand-held power tool, receiving unit 60j includes an edge element 154j in the region of anti-rotation lock elements 34j. Edge element 154j is oriented essentially parallel to a surface 118j of receiving flange 86j that points in radial direction 80j, and is designed as a single piece with receiving unit 60j. In addition, edge element 154j is located at a distance from surface 118j on receiving unit 60j. Anti-rotation lock elements 34j are located between edge element 154j and surface 118j. On an end 156j of edge element 154j facing anti-rotation lock elements 34j, edge element 154j includes a support element 158j, which extends inwardly in a radial direction 80j. A moving element 54j, which is designed as a spring element 56j and is located on guard unit 14j, bears against support element 158j during installation and when guard unit 14j is in a working position. To this end, guard unit 14j also includes an edge element 160j, which extends outwardly from guard collar 82j in radial direction 80j and is located on an edge region of guard collar 82j facing anti-rotation lock elements 34j. Spring element 56j is located on edge element 160j. To remove guard unit 14j, it must be lifted, in order to disengage anti-rotation lock elements 28j, 34j, and so that it may be subsequently rotated, thereby separating the two edge elements 154j, 160j in the circumferential direction, so that guard unit 14j may be removed by an operator.
FIG. 12 shows a hand-held power tool system 10k with a guard anti-rotation lock unit 16k, a receiving unit 60k, and a guard unit 14k. Guard anti-rotation lock unit 16k includes a non-positive connection unit 24k, which is provided to prevent guard 22k from rotating on a hand-held power tool at the same time as guard unit 14k is being attached to the hand-held power tool. To this end, a receiving unit 60k and a guard collar 82k each include an anti-rotation lock element 28k, 34k, each of which is designed as a coated surface with a high friction coefficient. It is also basically feasible for the surfaces of guard collar 82k and receiving flange 86k to have a desired friction coefficient due to the material selected and/or a surface treatment. When guard unit 14k is in an installed state and/or a working position, guard unit 14k is attached to receiving unit 60k in a non-positive manner via a closing unit 20k. When guard unit 14k is in an installed state, the coated surfaces bear against each other, so that, if a tool should burst, an anti-rotation lock results due to a frictional connection between the two coated surfaces and/or between guard unit 14k and the hand-held power tool.
FIGS. 13a and 13b show a partial cross-sectional view of a hand-held power tool system 10l with a guard anti-rotation lock unit 16l, a receiving unit 60l, and a guard unit 14l. Guard anti-rotation lock unit 16l includes a form-fit unit 26l, which is provided to prevent guard 11l from rotating on a hand-held power tool at the same time as guard unit 14l is being attached to the hand-held power tool. To this end, receiving unit 60l includes several anti-rotation lock elements 34l, 36l of guard anti-rotation lock unit 16l, which are located one after the other in circumferential direction 62l, 64l, and which form a toothing and extend away from side 68l in an outer—in radial direction 80l—edge region 146l. When hand-held power tool 10l is in an installed state, side 68l faces a tool. A further anti-rotation lock element 28l, which is designed as a toothing that corresponds to anti-rotation lock elements 34l, 36l of receiving unit 60l, is located on guard unit 14l. Anti-rotation lock element 28l is designed as a single piece with a release element 58l, which is supported on guard 22l such that it is movable in radial direction 80l. Release element 58l is integrally formed with an outer contour of guard 22l. Release element 58l is located such that it is separated from a guard edge 78l of guard 22l in radial direction 80l, thereby making it possible for release element 58l to move into an anti-rotation lock position and/or out of the anti-rotation lock position. For engagement in anti-rotation lock elements 34l, 36l of receiving unit 60l, a guard collar 82l includes a recess 162l, through which release element 58l extends, together with anti-rotation lock element 28l. To move release element 58l together with anti-rotation lock element 28l into an anti-rotation lock position at the same time as guard 14l reaches a working position, and/or to hold it in the anti-rotation lock position, guard anti-rotation lock unit 16l includes a moving element 54l designed as a spring element 56l, which presses release element 58l inwardly in radial direction 80l against a guard collar 82l. An anti-rotation lock position of anti-rotation lock element 28l with anti-rotation lock elements 34l, 36l of receiving unit 60l is reached when release element 58l is located in an outer—in radial direction 80l—end position. To release the anti-rotation lock, an operator presses release element 58l inwardly against a spring force of spring element 56l, and anti-rotation lock element 28l of guard unit 14l is slid out of engagement with anti-rotation lock elements 34l, 36l of receiving unit 60l. The position of guard unit 14l on the hand-held power tool may therefore be changed.
FIG. 14 shows a hand-held power tool system 10m with a guard anti-rotation lock unit 16m, a receiving unit 60m, and a guard unit 14m, in a partial cross-section. Guard anti-rotation lock unit 16m includes a form-fit unit 26m, which is provided to prevent guard 22m from rotating on a hand-held power tool at the same time as guard unit 14m is being attached to the hand-held power tool. To this end, a receiving unit 60m includes several anti-rotation lock elements 34m, 36m of guard anti-rotation lock unit 16m, which are located one after the other in circumferential direction 62m, 64m, and which are formed by recesses and are located in an outer—in radial direction 80m—edge region 146m. Guard anti-rotation lock unit 16m also includes further anti-rotation lock elements 28m, 30m, 32m, which are designed as single pieces with a release element 58m, which is located on a side 164m of a guard body 76m of a guard 22m that faces away from a tool. When guard unit 14m is in a working position, release element 58m is located tangentially to receiving unit 60m on guard 22m. Anti-rotation lock elements 28m, 30m, 32m extend—on a side 166m of release element 58m facing receiving unit 60m—inwardly in radial direction 80m. Release element 58m includes two recesses 168m, which are designed as slots, by way of which release element 58m is supported on guard 22m such that it may move inwardly or outwardly. To this end, screws 170m—which are screwed together with guard 22m—are supported in recesses 168m. To move or hold release element 58m in an anti-rotation lock position, guard anti-rotation lock unit 16m includes a moving element 54m, which is designed as a spring element 56m and bears against guard 22m. Release element 58m extends with both end regions 172m beyond guard body 76m, thereby making it possible for an operator to easily move release element 58m out of its anti-rotation lock position. The operator may actuate it on either end region 172m. A design of anti-rotation lock elements 28m, 30m, 32m of guard unit 14m and the recesses of receiving unit 60m also makes it possible for guard unit 14m to be easily inserted onto the hand-held power tool in that, when one of the anti-rotation lock elements 28m, 30m, 32m of guard unit 14m engages, guard 22m is centered in the working position with the aid of spring element 56m. 
FIG. 15 shows a hand-held power tool system 10n that is an alternative to that shown in FIG. 14. Hand-held power tool system 10n differs from that shown in FIG. 14 in that a release element 58n of a guard anti-rotation lock unit 16n is designed as a single piece with an anti-rotation lock element 28n and is rotatably supported via a pivot bearing 174n on a guard body 76n of a guard 22n. A rotation axis of release element 58n is oriented essentially perpendicularly to a guard body 76m. Release element 58n is held—together with anti-rotation lock element 28m—in an anti-rotation lock position with release unit 60m via a moving element 54m, which is designed as a spring element 56m. 
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in a hand-held power tool system, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

## Claims

1. A hand-held power tool system, comprising
a hand-held power tool;
a guard unit including a closing unit formed to include a clamping band and a pivotable lever; and
a guard anti-rotation lock unit preventing rotation between said guard unit and said hand-held power tool during breakdown of a tool of the hand-held power tool, said guard anti-rotation lock unit configured to prevent rotation between said guard unit and said hand-held power tool at a same time as said guard unit is attached to said hand-held power unit when said guard unit is in a working position,
wherein said guard anti-rotation lock unit is at least partially located on said closing unit and
includes at least one anti-rotation lock element provided on said lever and at least one further anti-rotation lock element provided in a receiving unit for accommodating a tool of said hand-held power tool, the further anti-rotation lock element formed as a detent recess and lockingly engagable by said at least one anti-rotation lock element provided on said clamping lever.

2. A hand-held power tool as defined in claim 1, wherein said anti-rotation lock unit is configured to block a motion of said guard unit in at least one direction.

3. A hand-held power tool as defined in claim 2, wherein said anti-rotation lock element is a single piece with said lever.

4. A hand-held power tool as defined in claim 1, wherein said anti-rotation lock unit also includes a plurality of further anti-rotation lock elements provided in a receiving unit for accommodating a tool of said hand-held power unit and each lockingly engagable by said first-mentioned anti-rotation lock element provided on said clamping lever.

5. A hand-held power tool as defined in claim 4, wherein said further anti-rotation lock elements are formed as detent recesses provided in said receiving unit.

6. A hand-held power tool as defined in claim 1, wherein said clamping band has a recess through which said anti-rotation lock element extends to attain an anti-lock position.

7. A hand-held power tool as defined in claim 1, wherein said anti-rotation lock element in a locked state extends inwardly in a radial direction of said receiving unit.