SE1850836A1 - A protection arrangement for a power tool - Google Patents

Abstract

The present disclosure relates to a hand-held power tool (1) comprising a rotatable work tool (2) having a center (16) and a circumference (17) and having a certain direction of rotation (19). The power tool (1) further comprises a blade guard arrangement (8, 8a, 8b, 8c, 8d) that at least partly is arranged to shield a part of the rotatable work tool (2) and comprises a blade guard (12) and a protective arrangement (11, 23, 28, 29) that is adapted to be displaced from a working position, where the protective arrangement (11, 23, 28, 29) admits normal cutting of a work object (18), to a displaced position. In the displaced position the protective arrangement (11, 23, 28, 29) at least partly becomes positioned such that a first arc (A1 , A2, A3) of a circle is covered, where the first arc (A1, A2, A3) of a circle follows the blade guard (12), and runs an angular distance along the circumference (17) after the blade guard (12), in the direction of rotation (19).The present disclosure also relates to a blade guard arrangements.

Description

TECHNICAL FIELD The present disclosure relates to a hand-held power tool comprising a rotatable worktool with a center and a circumference, and being adapted to rotate in a direction ofrotation. The power tool further comprises a blade guard arrangement that is arrangedto shield a variable part of the rotatable work tool.

BACKG ROUND Many power tools such as power cutters have saw blades in the form of cutting discswhich may be circular or ring-shaped. Such a cutting machine may be used for cuttinghard materials such as concrete or rock, where the cutting disc is partially covered bya blade guard.

On rare occasions, a so-called kick-back can occur, where the cutting disc moves bothupwards and backwards, towards the user, where the force that causes this movementoriginates from a locking contact between the cutting disc and a working object incombination with the energy that is stored in the cutting disc's inertia. Such a kick-backcan cause injury to a user since the thin and probably rotating cutting disc can hit the USSR US 8413340 discloses a safety guard assembly for a handheld power saw with a sawblade where, in a kick-back situation, a weight at the safety guard enhances a momentof inertia such that the safety guard is released from a spring-biased lockingmechanism. The safety guard consists of two parts that move on opposite sides of thesaw blade, away from a central part of the saw blade towards the periphery of the sawblade, by pivoting around a pivot pin. However, the cutting edge of the saw blade willnot be covered by the safety guard due to its construction of two parts that move onopposite sides of the saw blade.

There is thus a desire for a more reliable protection arrangement for an engine-drivencutting machine that allows a more flexible use of the engine-driven cutting machine.

SUMMARY An object of the present disclosure is to provide a hand-held power cutter comprisinga rotatable work tool, where the power tool is adapted for a more flexible use by meansof an enhanced protection arrangement. Another object is to provide an improvedblade guard arrangement.

This object is achieved by means of a hand-held power tool comprising a rotatablework tool having a center and a circumference and that is adapted to rotate in a certaindirection of rotation. The power tool further comprises a blade guard arrangement thatat least partly is arranged to shield a part of the rotatable work tool and comprises ablade guard and a protective arrangement that is adapted to be displaced from aworking position, where the protective arrangement admits normal cutting of a workobject, to a displaced position. ln the displaced position, the protective arrangement atleast partly becomes positioned such that a first arc of a circle is covered, where thefirst arc of a circle follows the blade guard, and runs an angular distance along thecircumference after the blade guard, in the direction of rotation.

This enables user protection along that part first arc of a circle, which is an advantage.This is advantageous in the case of a kick-back condition. This also enables a more flexible use by means of an enhanced protection arrangement.

According to some aspects, the displacement is caused by the mass of the protectivearrangement in combination with an acceleration.

This can be advantageous in the case of a kick-back condition.

According to some aspects, the blade guard comprises a protective part thatconstitutes the protective arrangement, where the blade guard is adapted to rotatearound the center in the direction of rotation.

This provides an uncomplicated and reliable blade guard arrangement.

According to some aspects, the protective part comprises a weight.

This provides a stable and quick movement.

According to some aspects, the protective arrangement mostly covers a part of theblade guard in the working position and is adapted to be displaced to the displacedposition along a path mostly following the direction of rotation.

This provides an uncomplicated and reliable blade guard arrangement.

According to some aspects, the protective arrangement a swiveling cover part that isattached to the blade guard by means of at least one holding means comprised in theblade guard arrangement. At its respective ends, each holding means is pivotablyattached to the swiveling cover part and the blade guard, and is adapted to moverelative the blade guard when the cover part is moved between the first position andthe second position.

According to some aspects, there are two holding means at the same side of the bladeguard arrangement, where the holding means lie in a common plane parallel to a planarextension of the rotatable work tool.

According to some aspects, there are two holding means at the same side of the bladeguard arrangement, where the holding means lie in different planes parallel to a planarextension of the rotatable work tool.

This enables the holding means move during work, preventing them from becomingstiff or stuck, for example due to accumulated dust and dirt. This also enables the coverpart move along the blade guard without any holding means having to be attached atthe center.

According to some aspects, the cover part is attached to the blade guard by means ofat least one holding means comprised in the blade guard arrangement. Each holdingmeans is in the form of a guide attached to the blade guard and is adapted to run in acorresponding arcuate slot in the cover part.

This provides an uncomplicated connection between the cover part and the bladeguard.

According to some aspects, the cover part is attached to the blade guard by means ofat least one holding means comprised in the blade guard arrangement. Each holdingmeans is in the form of a pivot pin attached to the blade guard where the cover part isadapted to pivot around the pivot pin.

This provides an uncomplicated connection between the cover part and the bladeguard.

According to some aspects, the cover part is connected to the blade guard such that itis moveable along a path between the first position and the second position, where thepath mainly follows the circumference such that a part of the blade guard is radiallypositioned between the circumference and the cover part in the second position. ln this manner, the cover part adjusts to the present work procedure in a discretemanner, enabling versatile work.

According to some aspects, the swiveling cover part is spring-biased by means of atleast one spring element, where each spring element is attached to the blade guardand a corresponding holding means end. The holding means end is attached to theblade guard by means of a pivot pin and the spring element is biased such that thecover part strives towards the working position along a part of the path and towardsthe displaced position along the rest of the path.

According to some aspects, the spring element has a winding part and two arm partswhich are attached to the blade guard and the corresponding holding means end atcorresponding arm attachments. A first line passing the arm attachments passes asecond line when brought to the working position, where the second line is parallel tothe first line and runs via the pivot pin. ln this manner, a reliable and bidirectional spring bias is obtained, enabling the coverpart to be positioned at both the first positon and the second position.

According to some aspects, the winding part is adapted to move when the cover partis moved between the working position and the displaced position such that the forceneeded to move the cover part is reduced from the working position to the displacedposition.

This provides a smooth movement from the first position to the second position.

According to some aspects, the spring element comprises a spiral spring that isattached to the blade guard and the corresponding holding means end atcorresponding spring attachments. A first line passing the spring attachments passesa second line when brought to the displaced position, where the second line is parallelto the first line and runs via the pivot pin. ln this manner, a reliable and bidirectional spring bias is obtained, enabling the coverpart to be positioned at both the first positon and the second position.

According to some aspects, the protective arrangement comprises an airbag that isadapted to be inflated and expand to the displaced position.

According to some aspects, the airbag is adapted expand from the blade guard and topartly be positioned between the circumference and the blade guard after inflation,such that the movement of the rotatable work tool is reduced.

This enables a reduction of the rotational speed of the rotatable work tool.

This object is also achieved by means of blade guard arrangements that are associatedwith the above advantages.

BRIEF DESCRIPTION OF THE DRAWINGSThe present disclosure will now be described more in detail with reference to theappended drawings, where: Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 shows a side view of a hand-held power cutter with a protectivearrangement according to a first example in a first position; shows a side view of a hand-held power cutter with a protectivearrangement according to the first example in a second position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the first example in the first position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the first example in the secondposition; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the first example in the first position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to a second example in the first position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the second example in the secondposition; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to a third example in the first position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the third example in the secondposition; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to a fourth example in the first position; Figure 11 Figure 12A Figure 12B Figure 13 Figure 14 Figure 15 Figure 16 Figure 17A Figure 17B Figure 18 Figure 19 Figure 20 shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement according to the fourth example in the secondposition; shows a side view of a first type of spring element in one position; shows a side view of the spring element in another position; shows a side view of the spring element in two positions; shows a side view of a hand-held power cutter with a protectivearrangement according to a fifth example in a normal position; shows a side view of a hand-held power cutter with a protectivearrangement according to the fifth example in a displaced position; shows a side view of a first type of spring element; shows a side view of a second type of spring element in one position;shows a side view of the spring element in another position; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement being biased towards one position by means ofthe second type of spring element; shows a side view of a cutting disc and a blade guard arrangement with aprotective arrangement being biased towards another position by means of the second type of spring element; shows a side view of a hand-held power cutter with a protectivearrangement according to a sixth example in a displaced position; and Figure 21 shows a side view of a hand-held power cutter with a protective arrangement according to a seventh example in a displaced position.

DETAILED DESCRIPTION Figure 1 and Figure 2 shows respective side views of a hand-held power cutter 1according to a first example with a circularly shaped saw blade, constituting a cuttingdisc 2, for example suitable to cut through concrete. The cutting disc 2 has a center 16and a circumference 17 (only schematically indicated). The power cutter 1 comprisesa casing 3 at least partly enclosing a combustion engine 4, where the casing 3 in turncomprises a first handle part 5. The power cutter 1 further comprises a second handlepart 7 that runs in an arcuate shape over the casing 3, the second handle part 7 beingattached to the casing 3.

The power cutter 1 comprises a blade guard 8 that is arranged to shield a part of thecutting disc 2. The cutting disc 2 is adapted to rotate in a direction of rotation 19 and isconnected to the engine 4 via a power transferring unit 27 that comprises a powertransferring means (not shown) that is covered by a power transfer cover 10. Thepower transferring means is according to some aspects either in the form of an endlessdrive belt or a geared transmission that in turn is arranged to propel the cutting disc 2.As shown in the Figures, the direction of rotation 19 runs clockwise in a side viewwhere the cutting disc 2 is positioned at the right of the engine 4.

The power cutter 1 further comprises a blade guard arrangement 8 that is arranged toshield a variable part of the cutting disc 2, where the blade guard arrangement 8comprises a blade guard 12.

According to the present disclosure, the blade guard arrangement 8 further comprisesa swiveling cover part 11 that is attached to the blade guard 12. ln a first position, asillustrated in Figure 1, the cover part 11 is positioned such that a first arc A of a circleis covered, where the first arc A of a circle is adjacent to the blade guard 12 and runsan angular distance along the circumference 17 after the blade guard 12 in the directionof rotation 19. The cover part 11 is arranged moveable between the first position anda second position, as illustrated in Figure 2, where a cutting operation of the cuttingdisc 2 along the first arc A of a circle is allowed, where the cover part 11 is biased in the direction of rotation 19, towards the first position. When the cover part 11 iscovering the first arc A of a circle in the first position, the circumference 17 is covered,and a user U is protected from the edge of the circumference 17 where it is coveredby the cover part 11.

The first arc A of a circle at least follows the blade guard 12 and runs an angulardistance along the circumference 17 after the blade guard 12 in the direction of rotation19, allowing a gap to be present between the cover part 11 and the blade guard 12, atwhich gap a part of the cutting disc 2 can be visible. According to some aspects, thereis no such gap. ln the first position, the circumference 17 along the first arc A of a circle is covered,which is advantageous in the case of a kick-back condition.

Furthermore, there is a second arc B of a circle that is adjacent to the first arc A of acircle and runs an angular distance along the circumference 17 after the first arc A ofa circle in the direction of rotation 19. The second arc B of a circle is uncovered in thefirst position such that initial cutting is allowed along the second arc B of a circle. ln thismanner, a user U is stimulated to start cutting along the second arc B of a circle, whichprovides a safe and preferred initial cutting.

The arcs A, B of a circle, according to some aspects, have the same or similar radialextension as the circumference 17. ln the following, reference is also made to Figure 3, showing a side view of the cuttingdisc 2 and the cover part 11 in the first position, and Figure 4, showing a side view ofthe cutting disc 2 and the cover part 11 in the second position. The cover part 11 isattached to the blade guard 12 by means of holding rods comprised in the blade guardarrangement 8; a first holding rod 21 and a second holding rod 22. Each holding rod21, 22 is pivotably attached to the swiveling cover part 11 and the blade guard 12 atits respective ends, and is adapted to move relative the blade guard 12 when the coverpart 11 is moved between the first position and the second position. ln this manner,the pivoting functionality is maintained by being used every time the power cutter 1 isused, preventing dirt from obscuring the pivoting functionality.

According to some aspects, there are two holding rods 21, 22 at the same side of theblade guard arrangement 8, where the holding rods 21, 22 lie in a common planeparallel to a planar extension of the cutting disc 2. Preferably, and not shown, thereare two additional corresponding holding rods on the other side of the blade guardarrangement 8, not shown in Figure 1 - Figure 4.

The cover part 11 is connected to the blade guard 12 such that it is moveable along apath between the first position and the second position, where the path mainly followsthe circumference 17 such that a part of the blade guard 12 is radially positionedbetween the circumference 17 and the cover part 11, 11', 11” in the second position.

The holding rods 21, 22 are arranged such that the cover part 11 moves along saidpath, and in this example without any parts being attached at the center 16.

According to some aspects, with reference to Figure 3 and Figure 4, the swivelingcover part 1 1 is spring-biased towards the first position along at least a part of the path,the spring bias being accomplished by means of at least one spring element 33. Thespring element 33 is attached to the blade guard 12 and a corresponding holding rodend 22a associated with the second holding rod 22. The holding rod end 22a isattached to the blade guard 12 by means of a pivot pin 13.

The spring element is biased such that the cover part 11 strives towards the firstposition along at least a part of the path; two different examples will be described inthe following.

With reference to Figure 12A and Figure 12B, according to some aspects, the springelement 33 has a winding part 34 and two arm parts 35, constituting a first type ofspring element, which arm parts 35 are attached to the blade guard 12 and thecorresponding holding means end 22a at corresponding arm attachments 42a, 42b. Afirst imaginary line 43 passing the arm attachments 42a, 42b never passes a secondimaginary line 44, where the second line 44 is parallel to the first line 43 and runs viathe pivot pin 13, such that the cover part 11 is spring-biased towards the first positionalong the path. ln other words, as illustrated in Figure 12A and Figure 12B, a distance 11 A, B between the lines 43, 44 always exceeds zero. This means that the cover part 11always is spring-biased towards the first position.

With reference to Figure 16, according to some aspects, the spring element 33 has awinding part 34 and two arm parts 35, being the first type of spring element, which armparts 35 are attached to the blade guard 12 and the corresponding holding means end22a at corresponding arm attachments 42a', 42b'. A first imaginary line 43' passing thearm attachments 42a', 42b' passes a second imaginary line 44' when brought to thesecond position, where the second line 44” is parallel to the first line 43' and runs viathe pivot pin 13, such that the cover part 11 is spring-biased towards the secondposition along a part of the path. ln other words, as illustrated in Figure 16, a distanceC between the lines 43', 44' changes sign. This means that the cover part 11 mainly isspring-biased towards the first position, but also is spring-biased towards the secondposition in the vicinity of the second position. This means that the cover part 11 can beset in the second position, but easily be brought back to the first position by moving itslightly away from the second position and then letting the spring force act.

With reference to Figure 13, according to some aspects, the winding part 34 is adaptedto move when the cover part 11 is moved between the first position and the secondposition such that the force of the spring bias is reduced the first position to the secondposition. An example of how the spring element 33 functions is also illustrated in Figure1 - Figure 4.

The spring element can of course have many other shapes and forms. With referenceto Figure 17A and Figure 17B, according to some aspects, the spring element 41comprises a spiral spring, constituting a second type of spring element, that is attachedto the blade guard 12 and the corresponding holding means end 22a at correspondingspring attachments 45a, 45b. A first imaginary line 46 passing the spring attachments45a, 45b passes a second imaginary line 47 when brought to the second position. Thesecond line 47 is parallel to the first line 46 and runs via the pivot pin 13, such that thecover part 11 is spring-biased towards the second position along a part of the path. lnother words, as illustrated in Figure 17A and Figure 17B, a distance D, E between thelines 46, 47 changes sign. This means that the cover part 11 mainly is spring-biasedtowards the first position, but also is spring-biased towards the second position in the 12 vicinity of the second position. This means that the cover part 11 can be fixedly set inthe second position, but easily be brought back to the first position by moving it slightlyaway from the second position and then letting the spring force act. This is illustratedin Figure 18 and Figure 19 which mainly correspond to Figure 4 and Figure 3. Figure18 and Figure 19 are also used for illustrating a further example of the presentdisclosure as will be discussed later.

According to some aspects, for all the examples described above, there is arrangedan additional corresponding spring element attached to an additional correspondingholding rod end on the other side of the blade guard arrangement 8, not shown inFigure 1- Figure 4, Figure 12A, Figure 12B, Figure 13, Figure 16, Figure 17A, Figure17B, Figure 18 and Figure 19. ln Figure 5 that corresponds to Figure 3, another example is shown. Here, the springelement 33, 41 is covered by a covering plate 31. The covering plate is according tosome aspects adapted to receive an incoming water supply hose 49, and thus alsoadapted to cover or comprise water dispensing means (not shown) adapted todispense water that is intended to connect to dust that is released during cutting,preventing the dust to spread. There can be an additional covering plate on the otherside of the blade guard arrangement as well, possibly adapted to cover or comprise water dispensing means, not shown in Figure 5.

With renewed reference to Figure 1 and Figure 2, the second holding rod 22 alsoconstitutes a continuously running delimiting contact part against which a work object18 at least partly can rest during cutting of the work object 18. During cutting, the coverpart 11 can move between the first position and the second position by means ofpressure from the work object 18 against the contact part of the second holding rod22, where this pressure works against the biasing. ln this manner, the work object 18will not be caught or stuck anywhere while pressing against the contact part andmoving the cover part 11 between the first position and the second position. ln orderto further facilitate this, according to some aspects, the cover part 11 comprises awheel 25 that is adapted to be in rotatable contact with a work object 18 during cutting.According to some aspects, an end portion of the second holding rod 22 comprises thewheel 25 that is adapted to be in rotatable contact with a work object 18 during cutting. 13 ln the following, a number of examples for alternative attachments of the cover part 11to the blade guard 12 will be described with reference to Figure 6 - Figure 11.

Figure 6 shows a side view of a cutting disc 2 and a blade guard arrangement 8' witha protective arrangement according to a second example in the first position, andFigure 7 shows a corresponding side view in the second position.

Here, there are two holding arms 21 ', 22' attaching the cover part 1 1' to the blade guard12, where the holding arms 21 ', 22' are positioned at the same side of the blade guardarrangement 8. The holding means 21', 22' lie in different planes parallel to a planarextension of the cutting disc 2. This means that straight first holding arm 21' issandwiched between an arcuate second holding arm 22' and the blade guard 12,where the second holding arm 22' in this example also constitutes a contact partaccording to the above, i.e. a continuously running delimiting contact part againstwhich a work object 18 at least partly can rest during cutting of the work object 18..

According to some aspects, there are arranged additional holding arms correspondingto the holding arms 21 ', 22' on the other side of the blade guard arrangement 8', whichholding arms are not showed in Figure 6 and Figure 7.

Figure 8 shows aside view of a cutting disc 2 and a blade guard arrangement 8" witha protective arrangement according to a third example in the first position, and Figure9 shows a corresponding side view in the second position.

Here, the cover part 11" is attached to the blade guard 12" by means of a holding pin37 comprised in the blade guard arrangement 8”. The holding pin 37 is in the form ofa guide attached to the blade guard 12" and is adapted to run in a correspondingarcuate slot 38 in the cover part 11 According to some aspects, there is an additionalcorresponding holding pin and slot on the other side of the blade guard arrangement8", not shown in Figure 8 and Figure 9.

The cover part 11" has a somewhat pie-shaped structure in this example andcomprises a front edge 36 that constitutes a contact part according to the above, i.e. a 14 continuously running delimiting contact part against which a work object 18 at leastpartly can rest during cutting of the work object 18. The front edge 36 runs on bothsides of the cutting disc 2.

Figure 10 shows a side view of a cutting disc 2 and a blade guard arrangement 8"' witha protective arrangement according to a fourth example in the first position, and Figure11 shows a corresponding side view in the second position.

Here, the cover part 11"' is attached to the blade guard 12"' by means of at least one ll! pivot pin 39 that is comprised in the blade guard arrangement 8 and is attached tothe blade guard 12"', where cover part 11"' is adapted to pivot around the pivot pin 39.The pivot pin is slightly offset from the center 16. According to some aspects, there isan additional corresponding pivot pin on the other side of the blade guard arrangement 8"', not shown in Figure 10 and Figure 11.

According to some aspects, the examples described with reference to Figure 8-11 canbe combined such that the cover part 11" is attached to the blade guard 12" by meansof a holding pin 37 comprised in the blade guard arrangement 8" and is adapted to runin a corresponding arcuate slot 38 in the cover part 11" on one side. On the other side,the cover part 11"' is attached to the blade guard 12"' by means of at least one pivot u!! pin 39 that is comprised in the blade guard arrangement 8 and is attached to the blade guard 12"', where cover part 11 is adapted to pivot around the pivot pin 39.The cover part 11"' that has a somewhat pie-shaped structure in this example andcomprises a front edge 40 that constitutes a contact part according to the above, i.e. acontinuously running delimiting contact part against which a work object 18 at leastpartly can rest during cutting of the work object 18. The front edge 40 runs on bothsides of the cutting disc 2.

According to some aspects, for the examples discussed with reference to Figure 6 -Figure 11, the cover part is spring biased by one or more spring elements; whereapplicable by means of spring elements similar to the ones as discussed previously.

According to some aspects, for the examples described, the cover part 11, 11', 11”,11"' comprises a handle 30 that admits a user to move the cover part 11 between thefirst position and the second position. Optionally, as only shown in Figure 1, the bladeguard 12 comprises a lock part 48 that is adapted for releasably locking the cover part11 in the second position, the lock part 48 for example comprising a magnet.Alternatively, a spring-loaded member can be adapted to engage a locking member.

According to some aspects, for the examples described, the cover part 11, 11', 11",11"' at least partly is made as a see-through structure. Such a structure can forexample be a certain material such as clear plastics. Other alternatives for such a see-through structure are nets/grid structures or a material with see-through apertures orholes. ln the following, an alternative protective arrangement will be described for the hand-held power cutter 1 with reference to Figure 14 and Figure 15, constituting a fifthexample. The previously described second position is here a working position, asshown in Figure 14, and the previously described first position is here a displacedposition, as shown in Figure 15.

The blade guard arrangement 8a comprises a blade guard 12 and a protectivearrangement 23 that is adapted to be displaced from a working position, where theprotective arrangement 23 admits normal cutting of a work object 18, to a displacedposition such that the protective arrangement 23 in the displaced position at least partlybecomes positioned such that a first arc A1 of a circle is adjacent to, or at least follows,the blade guard 12 and runs an angular distance along the circumference 17 after theblade guard 12 in the direction of rotation 19.

According to some aspects, the displacement is caused by the mass of the protectivearrangement in combination with an acceleration, and can for example be initiated bymeans of a kick-back condition. ln this example, the blade guard 12 comprises a protective part 23 that constitutes theprotective arrangement, where the blade guard 12 is adapted to rotate around thecenter 16 in the direction of rotation 19 should an acceleration according to the above 16 occur. According to some aspects, the protective part 23 comprises a weight 24, andthus the blade guard 12 also comprises the weight 24.

The moveable blade guard can suitably be rotated in any direction around the center16 by hand as well, and in that case by means of a handle 50.

For this alternative, the protective part can instead, or as a compiement, comprise thecover part 11, 11', 11”, 11” as discussed previously, as illustrated for a blade guardarrangement 8b in Figure 18 and Figure 19. Figure 18 shows side view of a cuttingdisc and a blade guard arrangement with a protective arrangement being biasedtowards the working position by means of the second type of spring element and Figure19 shows a corresponding side view with a protective arrangement being biasedtowards the displaced position by means of the second type of spring element.

This means that the swiveling cover part 11 is spring-biased by means of a springelement 41 that is attached to the blade guard 12 and a corresponding holding meansend 22a, and where the holding means end 22a is attached to the blade guard 12 bymeans of a pivot pin 13. The spring element is biased such that the cover part 11strives towards the working position along a part of the path and towards the displacedposition along the rest of the path, where said part of the path is shorter than the restof the path. This allows the cover part 11 to be held in the working position whileworking, and to be quickly displaced to the displaced position should an accelerationaccording to the above occur.

A biasing means as previously described with reference to Figure 16 is alsoconceivable since it achieves this desired functionality.

Furthermore, with reference to Figure 20 and Figure 21, according to some aspects,the blade guard arrangement 8c, 8d comprises a protective arrangement that in turncomprises an airbag 29, 32 that is adapted to be inflated and expand to the displacedposition. ln Figure 20 there is a blade guard arrangement 8c that comprises an airbag generator51 from which an airbag 28 has been deployed, covering a certain arc A2 of a circle. 17 Here, the airbag 28 is intended as a protection as well as a brake, the airbag 28 beingadapted to expand from the blade guard 12 and to partly be positioned between thecircumference 17 and the blade guard 12 after inflation, such that the movement of therotatabie work tool 2 is reduced. ln Figure 21 , there is a blade guard arrangement 8d that comprises an airbag generator52 from which an airbag 29 has been deployed, covering a certain arc A3 of a circle.Here, the airbag 29 is mainly intended as a protection. ln these alternative cases, the protective arrangement 11, 23, 28, 29 mostly covers apart of the blade guard 12 in the working position and is adapted to be displaced to thedisplaced position along a path mostly following the direction of rotation 19.

The present disclosure is not limited to the above examples, but may vary freely withinthe scope of the appended claims. For example, there can be any type of power cutterwith a rotatabie work tool such as a circular cutting disc, or a ring-shaped saw blade.Only some items of the power cutter in the example have been described, the powercutter in itself being of a well-known kind. The engine 4 can either be a combustion engine or an electric motor, as well as a hydraulic or pneumatic engine/motor.

For all the examples discussed, according to some aspects, the blade guard 12 isadapted to rotate around the center 16, and in particular in the direction of rotation 19,where the rotation is caused by the mass of the blade guard 12 in combination with anacceleration. For this purpose, according to some aspects, the blade guard 12comprises a weight 24.

The rod parts, arm parts, holding pins and pivot pins described are all generallyreferred to as holding means. As described, there can be one or more holding means.

According to some aspects, the circumference 17 can be regarded as an imaginarycircumference that follows an outer edge of the rotatabie work tool 2. The blade guardarrangement 8 comprises a blade guard 12 that is adapted to partly cover saidcircumference 17. 18 The power cutter is generally constituted by a power tool comprising a rotatable worktool.

According to some aspects, the protective arrangement comprises a brake that isadapted to reduce the movement of the rotatable work tool 2 during certain conditions.

Generally, the present disclosure relates to a hand-held power tool 1 comprising arotatable work tool 2 having a center 16 and a circumference 17 and being adapted torotate in a certain direction of rotation 19, where the power tool 1 further comprises ablade guard arrangement 8, 8a, 8b, 8c, 8d that at least partly is arranged to shield apart of the rotatable work tool 2. The blade guard arrangement 8 comprises a bladeguard 12 and a protective arrangement 11, 23, 28, 29 that is adapted to be displacedfrom a working position, where the protective arrangement 11, 23, 28, 29 admitsnormal cutting of a work object 18, to a displaced position such that the protectivearrangement 11, 23, 28, 29 in the displaced position at least partly becomes positionedsuch that a first arc A1 , A2, A3 of a circle is covered, where the first arc A1 , A2, A3 ofa circle follows the blade guard 12, and runs an angular distance along thecircumference 17 after the blade guard 12, in the direction of rotation 19.

Generally, the present disclosure also relates to a blade guard arrangement 8 that isarranged to shield a variable part of a rotatable work tool 2 for a hand-held power tool1 along a circumference 17, where the blade guard arrangement 8 comprises a bladeguard 12 that is adapted to partly cover said circumference 17. The blade guardarrangement 8 comprises a protective arrangement 11, 23, 28, 29 that is adapted tobe displaced from a working position, where the protective arrangement 1 1, 23, 28, 29is adapted to admit normal cutting of a work object 18, to a displaced position such thatthe protective arrangement 11, 23, 28, 29 in the displaced position at least partlybecomes positioned such that a first arc A1, A2, A3 of a circle is covered, where thefirst arc A1, A2, A3 of a circle follows the blade guard 12, and runs an angular distancealong the circumference 17 after the blade guard 12, in an intended direction of rotation19 for the rotatable work tool 2, According to some aspects, the displacement is caused by the mass of the protective arrangement in combination with an acceleration. 19 According to some aspects, the blade guard 12 comprises a protective part 23 thatconstitutes the protective arrangement, where the blade guard 12 is adapted to rotatearound the center 16 in the direction of rotation 19.

According to some aspects, the protective part 23 comprises a weight 24.

According to some aspects, the protective arrangement 11, 23, 28, 29 mostly coversa part of the blade guard 12 in the working position and is adapted to be displaced tothe displaced position along a path mostly following the direction of rotation 19.

According to some aspects, the protective arrangement a swiveling cover part 11, 11',11” that is attached to the blade guard 12 by means of at least one holding means 21,22; 21”, 22' comprised in the blade guard arrangement 8, 8b, wherein each holdingmeans 21, 22; 21 ”, 22' at its respective ends being pivotably attached to the swivelingcover part 11, 11” and the blade guard 12, and adapted to move relative the bladeguard 12 when the cover part 11 is moved between the first position and the secondposition.

According to some aspects, there are two holding means 21, 22 at the same side ofthe blade guard arrangement 8, where the holding means lie 21 , 22 in a common planeparallel to a planar extension of the rotatable work tool 2.

According to some aspects, there are two holding means 21 ', 22” at the same side ofthe blade guard arrangement 8, where the holding means 21 ', 22' lie in different planesparallel to a planar extension of the rotatable work tool 2.

According to some aspects, the cover part 11” is attached to the blade guard 12” bymeans of at least one holding means 37 comprised in the blade guard arrangement8", each holding means 37 being in the form of a guide attached to the blade guard12” and being adapted to run in a corresponding arcuate slot 38 in the cover part 11”.

According to some aspects, the cover part 11”” is attached to the blade guard 12"” bymeans of at least one holding means 39 comprised in the blade guard arrangement 8"', each holding means 39 being in the form of a pivot pin attached to the blade guard12"' where the cover part 11"' is adapted to pivot around the pivot pin 39.

According to some aspects, the cover part 11, 11', 11", 11"' is connected to the bladeguard 12 such that it is moveable along a path between the first position and thesecond position, where the path mainly follows the circumference 17 such that a partof the blade guard 12 is radially positioned between the circumference 17 and thecover part 11, 11', 11" in the second position.

According to some aspects, the swiveling cover part 11 is spring-biased by means ofat least one spring element 33, 41, where each spring element 33, 41 is attached tothe blade guard 12 and a corresponding holding means end 22a and where the holdingmeans end 22a is attached to the blade guard 12 by means of a pivot pin 13, the springelement 33, 41 being biased such that the cover part 11 strives towards the workingposition along a part of the path and towards the displaced position along the rest ofthe path.

According to some aspects, the spring element 33 has a winding part 34 and two armparts 35 which are attached to the blade guard 12 and the corresponding holdingmeans end 22a at corresponding arm attachments 42a', 42b', where a first line 43'passing the arm attachments 42a', 42b' passes a second line 44' when brought to theworking position, where the second line 44' is parallel to the first line 43' and runs viathe pivot pin 13.

According to some aspects, the winding part 34 is adapted to move when the coverpart 11 is moved between the working position and the displaced position such thatthe force needed to move the cover part 11 is reduced from the working position to thedisplaced position.

According to some aspects, the spring element 41 comprises a spiral spring that isattached to the blade guard 12 and the corresponding holding means end 22a atcorresponding spring attachments 45a, 45b, where a first line 46 passing the springattachments 45a, 45b passes a second line 47 when brought to the displaced position,where the second line 47 is parallel to the first line 46 and runs via the pivot pin 13. 21 According to some aspects, the protective arrangement comprises an airbag 28, 29that is adapted to be inflated and expand to the displaced position.

According to some aspects, the airbag 28 is adapted expand from the blade guard 12and to partly be positioned between the circumference 17 and the blade guard 12 afterinflation, such that the movement of the rotatable work tool 2 is reduced.

Claims (18)

1. A hand-held power tool (1) comprising a rotatable work tool (2) having acenter (16) and a circumference (17) and being adapted to rotate in a certain directionof rotation (19), where the power tool (1) further comprises a blade guard arrangement(8, 8a, 8b, 8c, 8d) that at least partly is arranged to shield a part of the rotatable worktool (2), characterized in that the blade guard arrangement (8) comprises a bladeguard (12) and a protective arrangement (11, 23, 28, 29) that is adapted to bedisplaced from a working position, where the protective arrangement (11, 23, 28, 29)admits normal cutting of a work object (18), to a displaced position such that theprotective arrangement (11, 23, 28, 29) in the displaced position at least partlybecomes positioned such that a first arc (A1, A2, A3) of a circle is covered, where thefirst arc (A1, A2, A3) of a circle follows the blade guard (12), and runs an angulardistance along the circumference (17) after the blade guard (12), in the direction ofrotation (19).

2. The hand-held power tool (1) according to claim 1, wherein thedisplacement is caused by the mass of the protective arrangement in combination with an acceleration.

3. The hand-held power tool (1) according to any one of the previous claims,wherein the blade guard (12) comprises a protective part (23) that constitutes theprotective arrangement, where the blade guard (12) is adapted to rotate around thecenter (16) in the direction of rotation (19).

4. The hand-held power tool (1) according to claim 3, wherein the protectivepart (23) comprises a weight (24).

5. The hand-held power tool (1) according to any one of the previous claims,wherein the protective arrangement (11, 23, 28, 29) mostly covers a part of the bladeguard (12) in the working position and is adapted to be displaced to the displacedposition along a path mostly following the direction of rotation (19). 23

6. The hand-held power tool (1) according to any one of the claims 1 or 2,wherein the protective arrangement a swiveling cover part (11, 11', 11”) that isattached to the blade guard (12) by means of at least one holding means (21, 22; 21 ',22”) comprised in the blade guard arrangement (8, 8b), wherein each holding means(21, 22; 21 ', 22') at its respective ends being pivotably attached to the swiveling coverpart (11, 11') and the blade guard (12), and adapted to move relative the blade guard(12) when the cover part (11) is moved between the first position and the secondposition.

7. The hand-held power tool (1) according to claim 6, wherein there are twoholding means (21, 22) at the same side of the blade guard arrangement (8), wherethe holding means lie (21, 22) in a common plane parallel to a planar extension of therotatable work tool (2).

8. The hand-held power tool (1) according to claim 6, wherein there are twoholding means (21 ', 22') at the same side of the blade guard arrangement (8), wherethe holding means (21', 22') lie in different planes parallel to a planar extension of therotatable work tool (2).

9. The hand-held power tool (1) according to any one of the claims 1 or 2,wherein the cover part (11”) is attached to the blade guard (12”) by means of at leastone holding means (37) comprised in the blade guard arrangement (8”), each holdingmeans (37) being in the form of a guide attached to the blade guard (12”) and beingadapted to run in a corresponding arcuate slot (38) in the cover part (11”).

10. The hand-held power tool (1) according to any one of the claims 1 or 2,wherein the cover part (11"') is attached to the blade guard (12'”) by means of at leastone holding means (39) comprised in the blade guard arrangement (8'”), each holdingmeans (39) being in the form of a pivot pin attached to the blade guard (12'”) wherethe cover part (1 1'”) is adapted to pivot around the pivot pin (39).

11. The hand-held power tool (1) according to any one of the claims 6-10,wherein the cover part (11, 11”, 11", 11'”) is connected to the blade guard (12) suchthat it is moveable along a path between the first position and the second position, 24 where the path mainly follows the circumference (17) such that a part of the bladeguard (12) is radially positioned between the circumference (17) and the cover part(11, 11', 11") in the second position.

12. The hand-held power tool (1) according to claim 11, wherein the swivelingcover part (1 1) is spring-biased by means of at least one spring element (33, 41 ), whereeach spring element (33, 41) is attached to the blade guard (12) and a correspondingholding means end (22a) and where the holding means end (22a) is attached to theblade guard (12) by means of a pivot pin (13), the spring element (33, 41) being biasedsuch that the cover part (11) strives towards the working position along a part of thepath and towards the displaced position along the rest of the path.

13. The hand-held power tool (1) according to claim 12, wherein the springelement (33) has a winding part (34) and two arm parts (35) which are attached to theblade guard (12) and the corresponding holding means end (22a) at correspondingarm attachments (42a', 42b”), where a first line (43') passing the arm attachments(42a', 42b') passes a second line (44') when brought to the working position, wherethe second line (44') is parallel to the first line (43') and runs via the pivot pin (13).

14. The hand-held power tool (1) according to claim 13, wherein the windingpart (34) is adapted to move when the cover part (11) is moved between the workingposition and the displaced position such that the force needed to move the cover part(11) is reduced from the working position to the displaced position.

15. The hand-held power tool (1) according to claim 12, wherein the springelement (41) comprises a spiral spring that is attached to the blade guard (12) and thecorresponding holding means end (22a) at corresponding spring attachments (45a,45b), where a first line (46) passing the spring attachments (45a, 45b) passes a secondline (47) when brought to the displaced position, where the second line (47) is parallelto the first line (46) and runs via the pivot pin (13).

16. The hand-held power tool (1) according to claim 1, wherein the protectivearrangement comprises an airbag (28, 29) that is adapted to be inflated and expand tothe displaced position.

17. The hand-held power tool (1) according to claim 16, wherein the airbag(28) is adapted expand from the blade guard (12) and to partly be positioned betweenthe circumference (17) and the blade guard (12) after inflation, such that the movementof the rotatable work tool (2) is reduced.

18. A blade guard arrangement (8) that is arranged to shield a variable part ofa rotatable work tool (2) for a hand-held power tool (1) along a circumference (17),where the blade guard arrangement (8) comprises a blade guard (12) that is adaptedto partly cover said circumference (17), characterized in that the blade guardarrangement (8) comprises a protective arrangement (11, 23, 28, 29) that is adaptedto be displaced from a working position, where the protective arrangement(11, 23, 28,29) is adapted to admit normal cutting of a work object (18), to a displaced positionsuch that the protective arrangement(11, 23, 28, 29) in the displaced position at leastpartly becomes positioned such that a first arc (A1, A2, A3) of a circle is covered, wherethe first arc (A1, A2, A3) of a circle follows the blade guard (12), and runs an angulardistance along the circumference (17) after the blade guard (12), in an intendeddirection of rotation (19) for the rotatable work tool (2).