U.S. patent application number 17/251966 was filed with the patent office on 2021-08-19 for a protection arrangement for a power tool.
The applicant listed for this patent is HUSQVARNA AB. Invention is credited to Mats Lawenius, Anders Reuterberg, Niklas Sundberg.
Application Number | 20210252656 17/251966 |
Document ID | / |
Family ID | 1000005609760 |
Filed Date | 2021-08-19 |
United States Patent
Application |
20210252656 |
Kind Code |
A1 |
Lawenius; Mats ; et
al. |
August 19, 2021 |
A Protection Arrangement for a Power Tool
Abstract
The present disclosure relates to a hand-held power tool (1)
comprising a rotatable work tool (2) with a center (16) and a
circumference (17) and having a direction of rotation (19). The
power tool (1) further comprises a blade guard arrangement (8) that
is arranged to shield a variable part of the rotatable work tool
(2) and comprises a blade guard (12) and a swiveling cover part
(11, 11', 11'') attached to the blade guard (12). In a first
position, the swiveling cover part (11, 11', 11'') is positioned
such that a first arc (A) of a circle is covered, following the
blade guard (12), and running an angular distance along the
circumference (17) after the blade guard (12), in the direction of
rotation (19). The cover part (11) is moveable between the first
position and a second position where a cutting operation of the
rotatable work tool (2) along the first arc (A) of a circle is
allowed. The cover part (11, 11', 11'') is biased towards the first
position. The present disclosure also relates to blade guard
arrangements.
Inventors: |
Lawenius; Mats; (Goteborg,
SE) ; Reuterberg; Anders; (Lerum, SE) ;
Sundberg; Niklas; (Alingsas, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HUSQVARNA AB |
HUSKVARNA |
|
SE |
|
|
Family ID: |
1000005609760 |
Appl. No.: |
17/251966 |
Filed: |
July 2, 2018 |
PCT Filed: |
July 2, 2018 |
PCT NO: |
PCT/SE2018/050721 |
371 Date: |
December 14, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B28D 1/045 20130101;
B23D 45/16 20130101; B23Q 11/06 20130101 |
International
Class: |
B23Q 11/06 20060101
B23Q011/06; B23D 45/16 20060101 B23D045/16 |
Claims
1. A hand-held power tool comprising a rotatable work tool with a
center and a circumference and being adapted to rotate in a certain
direction of rotation, wherein the power tool further comprises a
blade guard arrangement that is arranged to shield a variable part
of the rotatable work tool, wherein the blade guard arrangement
comprises a blade guard and a swiveling cover part that is attached
to the blade guard by means of at least one holding means comprised
in the blade guard arrangement, and, in a first position, the
swiveling cover part is positioned such that a first arc of a
circle is covered, wherein the first arc of a circle follows the
blade guard, and runs an angular distance along the circumference
after the blade guard, in the direction of rotation, wherein the
cover part is moveable between the first position and a second
position where a cutting operation of the rotatable work tool along
the first arc of a circle is allowed, wherein the cover part is
biased in the direction of rotation, towards the first position by
means of a biasing member, wherein the direction of rotation is a
down-cut direction of rotation.
2. The hand-held power tool according to claim 1, wherein a second
arc of a circle is adjacent to the first arc of a circle and runs
an angular distance along the circumference after the first arc of
a circle in the direction of rotation, wherein the second arc of a
circle is uncovered in the first position such that initial cutting
is allowed along the second arc of a circle.
3. The hand-held power tool according to claim 1, wherein the blade
guard arrangement comprises a continuously running delimiting
contact part against which a work object at least partly can rest
during cutting of the work object, such that during cutting, the
cover part can move between the first position and the second
position by means of pressure from the work object against said
contact part, the pressure working against the biasing, where the
contact part either is comprised in the cover part or comprised in
a part connecting the cover part to the blade guard.
4. The hand-held power tool according to claim 1, wherein
respective ends of each holding means are pivotably attached to the
swiveling cover part and the blade guard, and adapted to move
relative the blade guard when the cover part is moved between the
first position and the second position.
5. The hand-held power tool according to claim 4, wherein there are
two holding means at the same side of the blade guard arrangement,
wherein the holding means lie in a common plane parallel to a
planar extension of the rotatable work tool.
6. The hand-held power tool according to claim 4, wherein there are
two holding means at the same side of the blade guard arrangement,
wherein the holding means lie in different planes parallel to a
planar extension of the rotatable work tool.
7. The hand-held power tool according to claim 1, wherein the cover
part is attached to the blade guard by means of at least one
holding means comprised in the blade guard arrangement each holding
means being in the form of a guide attached to the blade guard and
being adapted to run in a corresponding arcuate slot in the cover
part.
8. The hand-held power tool according to claim 1, wherein the cover
part is attached to the blade guard by means of at least one
holding means comprised in the blade guard arrangement, each
holding means being in the form of a pivot pin attached to the
blade guard wherein the cover part is adapted to pivot around the
pivot pin.
9. The hand-held power tool according to claim 1, wherein the cover
part is connected to the blade guard such that it is moveable along
a path between the first position and the second position, wherein
the path mainly follows the circumference such that a part of the
blade guard is radially positioned between the circumference and
the cover part in the second position.
10. The hand-held power tool according to claim 9, wherein the
swiveling cover part 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 that
constitutes said biasing means.
11. The hand-held power tool according to claim 10, wherein each
spring element is attached to the blade guard and a corresponding
holding means end and wherein the holding means end is attached to
the blade guard by means of a pivot pin, the spring element being
biased such that the cover part strives towards the first position
along at least a part of the path.
12. The hand-held power tool according to claim 11, wherein the
spring element has a winding part and two arm parts which are
attached to the blade guard and the corresponding holding means end
at corresponding arm attachments, wherein a first line passing the
arm attachments never passes a second line where the second line is
parallel to the first line and runs via the pivot pin, such that
the cover part is spring-biased towards the first position along
the path.
13. The hand-held power tool according to claim 11, wherein the
spring element has a winding part and two arm parts which are
attached to the blade guard and the corresponding holding means end
at corresponding arm attachments, wherein a first line passing the
arm attachments passes a second line when brought to the second
position, wherein the second line is parallel to the first line and
runs via the pivot pin, such that the cover part is spring-biased
towards the second position along a part of the path.
14. The hand-held power tool according to claim 12, wherein the
winding part is adapted to move when the cover part is moved
between the first position and the second position such that the
force needed to move the cover part is reduced from the first
position to the second position.
15. The hand-held power tool according to claim 11, wherein the
spring element comprises a spiral spring that is attached to the
blade guard and the corresponding holding means end at
corresponding spring attachments, wherein a first line passing the
spring attachments passes a second line when brought to the second
position, wherein the second line is parallel to the first line and
runs via the pivot pin, such that the cover part is spring-biased
towards the second position along a part of the path.
16. The hand-held power tool according to claim 1, wherein the
cover part comprises a handle that admits a user to move the cover
part between the first position and the second position.
17. The hand-held power tool according to claim 1, wherein the
blade guard comprises a lock part that is adapted for releasably
locking the cover part in the second position.
18. The hand-held power tool according to claim 1, wherein the
blade guard is adapted to rotate in the direction of rotation,
wherein the rotation is caused by the mass of the blade guard in
combination with an acceleration.
19. The hand-held power tool according to claim 18, wherein the
blade guard comprises a weight, or wherein the cover part at least
partly is made as a see-through structure.
20. The hand-held power tool according to claim 1, wherein the
cover part comprises a wheel that is adapted to be in rotatable
contact with a work object during cutting.
21-40. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a hand-held power tool
comprising a rotatable work tool with a center and a circumference,
and being adapted to rotate in a direction of rotation. The power
tool further comprises a blade guard arrangement that is arranged
to shield a variable part of the rotatable work tool.
BACKGROUND
[0002] Many power tools such as power cutters have saw blades in
the form of cutting discs which may be circular or ring-shaped.
Such a cutting machine may be used for cutting hard materials such
as concrete or rock, where the cutting disc is partially covered by
a blade guard.
[0003] On rare occasions, a so-called kick-back can occur, where
the cutting disc moves both upwards and backwards, towards the
user, where the force that causes this movement originates from a
locking contact between the cutting disc and a working object in
combination with the energy that is stored in the cutting disc's
inertia. Such a kick-back can cause injury to a user since the thin
and probably rotating cutting disc can hit the user.
[0004] U.S. Pat. No. 8,413,340 discloses a safety guard assembly
for a handheld power saw with a saw blade where, in a kick-back
situation, a weight at the safety guard enhances a moment of
inertia such that the safety guard is released from a spring-biased
locking mechanism. The safety guard consists of two parts that move
on opposite sides of the saw blade, away from a central part of the
saw blade towards the periphery of the saw blade, by pivoting
around a pivot pin. However, the cutting edge of the saw blade will
not be covered by the safety guard due to its construction of two
parts that move on opposite sides of the saw blade.
[0005] There is thus a desire for a more reliable protection
arrangement for an engine-driven cutting machine that allows a more
flexible use of the engine-driven cutting machine.
SUMMARY
[0006] An object of the present disclosure is to provide a
hand-held power cutter comprising a rotatable work tool, where the
power tool is adapted for a more flexible use by means of an
enhanced protection arrangement. Another object is to provide an
improved blade guard arrangement.
[0007] This object is achieved by means of a hand-held power tool
comprising a rotatable work tool with a center and a circumference
and being adapted to rotate in a certain direction of rotation. The
power tool further comprises a blade guard arrangement that is
arranged to shield a variable part of the rotatable work tool and
comprises a blade guard and a swiveling cover part that is attached
to the blade guard by means of at least one holding means comprised
in the blade guard arrangement. In a first position, the swiveling
cover part is positioned such that a first arc of a circle is
covered, where the first arc of a circle follows the blade guard
and runs an angular distance along the circumference after the
blade guard, in the direction of rotation. The cover part is
moveable between the first position and a second position where a
cutting operation of the rotatable work tool along the first arc of
a circle is allowed. The cover part is biased in the direction of
rotation, towards the first position by means of a biasing
member.
[0008] This provides user protection along that part first arc of a
circle that is not comprised I a work object in, 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.
[0009] According to some aspects, a second arc of a circle is
adjacent to the first arc of a circle and runs an angular distance
along the circumference after the first arc of a circle in the
direction of rotation. The second arc of a circle is uncovered in
the first position such that initial cutting is allowed along the
second arc of a circle.
[0010] This stimulates a user to start cutting along the second arc
of a circle, which provides a safe and preferred initial cutting,
which is an advantage.
[0011] According to some aspects, the blade guard arrangement
comprises a continuously running delimiting contact part against
which a work object at least partly can rest during cutting of the
work object. During cutting, the cover part can move between the
first position and the second position by means of pressure from
the work object against said contact part, the pressure working
against the biasing. The contact part is either comprised in the
cover part or comprised in a part connecting the cover part to the
blade guard.
[0012] This provides a safe support for the work object that can
move the cover part during cutting in a reliable manner.
[0013] According to some aspects, each holding means is pivotably
attached to the swiveling cover part and the blade guard at its
respective ends, and adapted to move relative the blade guard when
the cover part is moved between the first position and the second
position.
[0014] According to some aspects, there are two holding means at
the same side of the blade guard arrangement, where the holding
means lie in a common plane parallel to a planar extension of the
rotatable work tool.
[0015] According to some aspects, there are two holding means at
the same side of the blade guard arrangement, where the holding
means lie in different planes parallel to a planar extension of the
rotatable work tool.
[0016] This enables the cover part move along the blade guard
without any holding means having to be attached at the center.
Furthermore, the holding means move during work, preventing them
from becoming stiff or stuck, for example due to accumulated dust
and dirt.
[0017] According to some aspects, the cover part is attached to the
blade guard by means of at least one holding means comprised in the
blade guard arrangement. Each holding means is in the form of a
guide attached to the blade guard and is adapted to run in a
corresponding arcuate slot in the cover part.
[0018] This provides an uncomplicated connection between the cover
part and the blade guard.
[0019] According to some aspects, the cover part is attached to the
blade guard by means of at least one holding means comprised in the
blade guard arrangement. Each holding means is in the form of a
pivot pin attached to the blade guard where the cover part is
adapted to pivot around the pivot pin.
[0020] This provides an uncomplicated connection between the cover
part and the blade guard.
[0021] According to some aspects, the cover part is connected to
the blade guard such that it is moveable along a path between the
first position and the second position, where the path mainly
follows the circumference such that a part of the blade guard is
radially positioned between the circumference and the cover part in
the second position.
[0022] In this manner, the cover part adjusts to the present work
procedure in a discrete manner, enabling versatile work.
[0023] According to some aspects, the swiveling cover part 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 that constitutes said biasing means.
[0024] According to some aspects, each spring element is attached
to the blade guard and a corresponding holding means end, and the
holding means end is attached to the blade guard by means of a
pivot pin. The spring element is biased such that the cover part
strives towards the first position along at least a part of the
path.
[0025] In the manner, the bias is accomplished in a reliable and
uncomplicated manner.
[0026] According to some aspects, the spring element has a winding
part and two arm parts which are attached to the blade guard and
the corresponding holding means end at corresponding arm
attachments. A first line passing the arm attachments never passes
a second line, where the second line is parallel to the first line
and runs via the pivot pin, such that the cover part is
spring-biased towards the first position along the path.
[0027] In this manner, a reliable and unidirectional spring bias is
obtained.
[0028] According to some aspects, the spring element has a winding
part and two arm parts which are attached to the blade guard and
the corresponding holding means end at corresponding arm
attachments. A first line passing the arm attachments passes a
second line when brought to the second position, where the second
line is parallel to the first line and runs via the pivot pin, such
that the cover part is spring-biased towards the second position
along a part of the path.
[0029] In this manner, a reliable and bidirectional spring bias is
obtained, enabling the cover part to be positioned at both the
first positon and the second position.
[0030] According to some aspects, the winding part is adapted to
move when the cover part is moved between the first position and
the second position such that the force needed to move the cover
part is reduced from the first position to the second position.
[0031] This provides a smooth movement from the first position to
the second position.
[0032] According to some aspects, the spring element comprises a
spiral spring that is attached to the blade guard and the
corresponding holding means end at corresponding spring
attachments. A first line passing the spring attachments passes a
second line when brought to the second position. The second line is
parallel to the first line and runs via the pivot pin, such that
the cover part is spring-biased towards the second position along a
part of the path.
[0033] In this manner, a reliable and bidirectional spring bias is
obtained, enabling the cover part to be positioned at both the
first positon and the second position.
[0034] According to some aspects, the cover part comprises a handle
that admits a user to move the cover part between the first
position and the second position.
[0035] This enables a user to easily access the part of the
rotatable work tool where it otherwise is covered by the cover
part.
[0036] According to some aspects, the blade guard comprises a lock
part that is adapted for releasably locking the cover part in the
second position.
[0037] This enables a user to easily have access the part of the
rotatable work tool where it otherwise is covered by the cover
part.
[0038] According to some aspects, the blade guard is adapted to
rotate in the direction of rotation, where the rotation is caused
by the mass of the blade guard in combination with an
acceleration.
[0039] This provides further protection for a user.
[0040] According to some aspects, the blade guard comprises a
weight.
[0041] This provides a stable and quick movement.
[0042] According to some aspects, the cover part comprises a wheel
that is adapted to be in rotatable contact with a work object
during cutting.
[0043] This provides easy cutting, when the cover part is moved by
means of the work object.
[0044] According to some aspects, the cover part at least partly is
made as a see-through structure.
[0045] This enables a user to always have less impaired visual
control of the cutting irrespective of the cover part's
position.
[0046] This object is also achieved by means of a hand-held power
tool comprising a rotatable work tool having a center and a
circumference and that is adapted to rotate in a certain direction
of rotation. The power tool further comprises a blade guard
arrangement that at least partly is arranged to shield a part of
the rotatable work tool and comprises a blade guard and a
protective arrangement that is adapted to be displaced from a
working position, where the protective arrangement admits normal
cutting of a work object, to a displaced position. In the displaced
position, the protective arrangement at least partly becomes
positioned such that a first arc of a circle is covered, where the
first arc of a circle follows the blade guard, and runs an angular
distance along the circumference after the blade guard, in the
direction of rotation.
[0047] 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.
[0048] According to some aspects, the displacement is caused by the
mass of the protective arrangement in combination with an
acceleration.
[0049] This can be advantageous in the case of a kick-back
condition.
[0050] According to some aspects, the blade guard comprises a
protective part that constitutes the protective arrangement, where
the blade guard is adapted to rotate around the center in the
direction of rotation.
[0051] This provides an uncomplicated and reliable blade guard
arrangement.
[0052] According to some aspects, the protective part comprises a
weight.
[0053] This provides a stable and quick movement.
[0054] According to some aspects, the protective arrangement mostly
covers a part of the blade guard in the working position and is
adapted to be displaced to the displaced position along a path
mostly following the direction of rotation.
[0055] This provides an uncomplicated and reliable blade guard
arrangement.
[0056] According to some aspects, the protective arrangement a
swiveling cover part that is attached to the blade guard by means
of at least one holding means comprised in the blade guard
arrangement. At its respective ends, each holding means is
pivotably attached to the swiveling cover part and the blade guard,
and is adapted to move relative the blade guard when the cover part
is moved between the first position and the second position.
[0057] According to some aspects, there are two holding means at
the same side of the blade guard arrangement, where the holding
means lie in a common plane parallel to a planar extension of the
rotatable work tool.
[0058] According to some aspects, there are two holding means at
the same side of the blade guard arrangement, where the holding
means lie in different planes parallel to a planar extension of the
rotatable work tool.
[0059] This enables the holding means move during work, preventing
them from becoming stiff or stuck, for example due to accumulated
dust and dirt. This also enables the cover part move along the
blade guard without any holding means having to be attached at the
center.
[0060] According to some aspects, the cover part is attached to the
blade guard by means of at least one holding means comprised in the
blade guard arrangement. Each holding means is in the form of a
guide attached to the blade guard and is adapted to run in a
corresponding arcuate slot in the cover part.
[0061] This provides an uncomplicated connection between the cover
part and the blade guard.
[0062] According to some aspects, the cover part is attached to the
blade guard by means of at least one holding means comprised in the
blade guard arrangement. Each holding means is in the form of a
pivot pin attached to the blade guard where the cover part is
adapted to pivot around the pivot pin.
[0063] This provides an uncomplicated connection between the cover
part and the blade guard.
[0064] According to some aspects, the cover part is connected to
the blade guard such that it is moveable along a path between the
first position and the second position, where the path mainly
follows the circumference such that a part of the blade guard is
radially positioned between the circumference and the cover part in
the second position.
[0065] In this manner, the cover part adjusts to the present work
procedure in a discrete manner, enabling versatile work.
[0066] According to some aspects, the swiveling cover part is
spring-biased by means of at least one spring element, where each
spring element is attached to the blade guard and a corresponding
holding means end. The holding means end is attached to the blade
guard by means of a pivot pin and the spring element is biased such
that the cover part strives towards the working position along a
part of the path and towards the displaced position along the rest
of the path.
[0067] According to some aspects, the spring element has a winding
part and two arm parts which are attached to the blade guard and
the corresponding holding means end at corresponding arm
attachments. A first line passing the arm attachments passes a
second line when brought to the working position, where the second
line is parallel to the first line and runs via the pivot pin.
[0068] In this manner, a reliable and bidirectional spring bias is
obtained, enabling the cover part to be positioned at both the
first positon and the second position.
[0069] According to some aspects, the winding part is adapted to
move when the cover part is moved between the working position and
the displaced position such that the force needed to move the cover
part is reduced from the working position to the displaced
position.
[0070] This provides a smooth movement from the first position to
the second position.
[0071] According to some aspects, the spring element comprises a
spiral spring that is attached to the blade guard and the
corresponding holding means end at corresponding spring
attachments. A first line passing the spring attachments passes a
second line when brought to the displaced position, where the
second line is parallel to the first line and runs via the pivot
pin.
[0072] In this manner, a reliable and bidirectional spring bias is
obtained, enabling the cover part to be positioned at both the
first positon and the second position.
[0073] According to some aspects, the protective arrangement
comprises an airbag that is adapted to be inflated and expand to
the displaced position.
[0074] According to some aspects, the airbag is adapted expand from
the blade guard and to partly be positioned between the
circumference and the blade guard after inflation, such that the
movement of the rotatable work tool is reduced.
[0075] This enables a reduction of the rotational speed of the
rotatable work tool.
[0076] This object is also achieved by means of blade guard
arrangements that are associated with the above advantages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0077] The present disclosure will now be described more in detail
with reference to the appended drawings, where:
[0078] FIG. 1 shows a side view of a hand-held power cutter with a
protective arrangement according to a first example in a first
position;
[0079] FIG. 2 shows a side view of a hand-held power cutter with a
protective arrangement according to the first example in a second
position;
[0080] FIG. 3 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to the first
example in the first position;
[0081] FIG. 4 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to the first
example in the second position;
[0082] FIG. 5 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to the first
example in the first position;
[0083] FIG. 6 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to a second
example in the first position;
[0084] FIG. 7 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to the second
example in the second position;
[0085] FIG. 8 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to a third
example in the first position;
[0086] FIG. 9 shows a side view of a cutting disc and a blade guard
arrangement with a protective arrangement according to the third
example in the second position;
[0087] FIG. 10 shows a side view of a cutting disc and a blade
guard arrangement with a protective arrangement according to a
fourth example in the first position;
[0088] FIG. 11 shows a side view of a cutting disc and a blade
guard arrangement with a protective arrangement according to the
fourth example in the second position;
[0089] FIG. 12A shows a side view of a first type of spring element
in one position;
[0090] FIG. 12B shows a side view of the spring element in another
position;
[0091] FIG. 13 shows a side view of the spring element in two
positions;
[0092] FIG. 14 shows a side view of a hand-held power cutter with a
protective arrangement according to a fifth example in a normal
position;
[0093] FIG. 15 shows a side view of a hand-held power cutter with a
protective arrangement according to the fifth example in a
displaced position;
[0094] FIG. 16 shows a side view of a first type of spring
element;
[0095] FIG. 17A shows a side view of a second type of spring
element in one position;
[0096] FIG. 17B shows a side view of the spring element in another
position;
[0097] FIG. 18 shows a side view of a cutting disc and a blade
guard arrangement with a protective arrangement being biased
towards one position by means of the second type of spring
element;
[0098] FIG. 19 shows a side view of a cutting disc and a blade
guard arrangement with a protective arrangement being biased
towards another position by means of the second type of spring
element;
[0099] FIG. 20 shows a side view of a hand-held power cutter with a
protective arrangement according to a sixth example in a displaced
position; and
[0100] FIG. 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
[0101] FIG. 1 and FIG. 2 shows respective side views of a hand-held
power cutter 1 according to a first example with a circularly
shaped saw blade, constituting a cutting disc 2, for example
suitable to cut through concrete. The cutting disc 2 has a center
16 and a circumference 17 (only schematically indicated). The power
cutter 1 comprises a casing 3 at least partly enclosing a
combustion engine 4, where the casing 3 in turn comprises a first
handle part 5. The power cutter 1 further comprises a second handle
part 7 that runs in an arcuate shape over the casing 3, the second
handle part 7 being attached to the casing 3.
[0102] The power cutter 1 comprises a blade guard 8 that is
arranged to shield a part of the cutting disc 2. The cutting disc 2
is adapted to rotate in a direction of rotation 19 and is connected
to the engine 4 via a power transferring unit 27 that comprises a
power transferring means (not shown) that is covered by a power
transfer cover 10. The power transferring means is according to
some aspects either in the form of an endless drive 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 view where the cutting disc 2 is positioned at
the right of the engine 4.
[0103] The power cutter 1 further comprises a blade guard
arrangement 8 that is arranged to shield a variable part of the
cutting disc 2, where the blade guard arrangement 8 comprises a
blade guard 12.
[0104] According to the present disclosure, the blade guard
arrangement 8 further comprises a swiveling cover part 11 that is
attached to the blade guard 12. In a first position, as illustrated
in FIG. 1, the cover part 11 is positioned such that a first arc A
of a circle is covered, where the first arc A of a circle is
adjacent to 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 cover part 11 is arranged moveable between the
first position and a second position, as illustrated in FIG. 2,
where a cutting operation of the cutting disc 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 is covering 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 covered
by the cover part 11.
[0105] The first arc A of a circle at least 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, allowing a gap
to be present between the cover part 11 and the blade guard 12, at
which gap a part of the cutting disc 2 can be visible. According to
some aspects, there is no such gap.
[0106] In 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.
[0107] Furthermore, there is a second arc B of a circle that is
adjacent to the first arc A of a circle and runs an angular
distance along the circumference 17 after the first arc A of a
circle in the direction of rotation 19. The second arc B of a
circle is uncovered in the first position such that initial cutting
is allowed along the second arc B of a circle. In this manner, a
user U is stimulated to start cutting along the second arc B of a
circle, which provides a safe and preferred initial cutting.
[0108] The arcs A, B of a circle, according to some aspects, have
the same or similar radial extension as the circumference 17.
[0109] In the following, reference is also made to FIG. 3, showing
a side view of the cutting disc 2 and the cover part 11 in the
first position, and FIG. 4, showing a side view of the cutting disc
2 and the cover part 11 in the second position. The cover part 11
is attached to the blade guard 12 by means of holding rods
comprised in the blade guard arrangement 8; a first holding rod 21
and a second holding rod 22. Each holding rod 21, 22 is pivotably
attached to the swiveling cover part 11 and the blade guard 12 at
its respective ends, and is adapted to move relative the blade
guard 12 when the cover part 11 is moved between the first position
and the second position. In this manner, the pivoting functionality
is maintained by being used every time the power cutter 1 is used,
preventing dirt from obscuring the pivoting functionality.
[0110] According to some aspects, there are two holding rods 21, 22
at the same side of the blade guard arrangement 8, where the
holding rods 21, 22 lie in a common plane parallel to a planar
extension of the cutting disc 2. Preferably, and not shown, there
are two additional corresponding holding rods on the other side of
the blade guard arrangement 8, not shown in FIG. 1-FIG. 4.
[0111] The cover part 11 is connected to the blade guard 12 such
that it is moveable along a path between the first position and the
second position, where the path mainly follows the circumference 17
such that a part of the blade guard 12 is radially positioned
between the circumference 17 and the cover part 11, 11', 11'' in
the second position.
[0112] The holding rods 21, 22 are arranged such that the cover
part 11 moves along said path, and in this example without any
parts being attached at the center 16.
[0113] According to some aspects, with reference to FIG. 3 and FIG.
4, the swiveling cover part 11 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. The spring
element 33 is attached to the blade guard 12 and a corresponding
holding rod end 22a associated with the second holding rod 22. The
holding rod end 22a is attached to the blade guard 12 by means of a
pivot pin 13.
[0114] The spring element is biased such that the cover part 11
strives towards the first position along at least a part of the
path; two different examples will be described in the
following.
[0115] With reference to FIG. 12A and FIG. 12B, according to some
aspects, the spring element 33 has a winding part 34 and two arm
parts 35, constituting a first type of spring element, which arm
parts 35 are attached to the blade guard 12 and the corresponding
holding means end 22a at corresponding arm attachments 42a, 42b. A
first imaginary line 43 passing the arm attachments 42a, 42b never
passes a second imaginary line 44, where the second line 44 is
parallel to the first line 43 and runs via the pivot pin 13, such
that the cover part 11 is spring-biased towards the first position
along the path. In other words, as illustrated in FIG. 12A and FIG.
12B, a distance A, B between the lines 43, 44 always exceeds zero.
This means that the cover part 11 always is spring-biased towards
the first position.
[0116] With reference to FIG. 16, according to some aspects, the
spring element 33 has a winding part 34 and two arm parts 35, being
the first type of spring element, which arm parts 35 are attached
to the blade guard 12 and the corresponding holding means end 22a
at corresponding arm attachments 42a', 42b'. A first imaginary line
43' passing the arm attachments 42a', 42b' passes a second
imaginary line 44' when brought to the second position, where the
second line 44' is parallel to the first line 43' and runs via the
pivot pin 13, such that the cover part 11 is spring-biased towards
the second position along a part of the path. In other words, as
illustrated in FIG. 16, a distance C between the lines 43', 44'
changes sign. This means that the cover part 11 mainly is
spring-biased towards the first position, but also is spring-biased
towards the second position in the vicinity of the second position.
This means that the cover part 11 can be set in the second
position, but easily be brought back to the first position by
moving it slightly away from the second position and then letting
the spring force act.
[0117] With reference to FIG. 13, according to some aspects, the
winding part 34 is adapted to move when the cover part 11 is moved
between the first position and the second position such that the
force of the spring bias is reduced the first position to the
second position. An example of how the spring element 33 functions
is also illustrated in FIG. 1-FIG. 4.
[0118] The spring element can of course have many other shapes and
forms. With reference to FIG. 17A and FIG. 17B, according to some
aspects, the spring element 41 comprises a spiral spring,
constituting a second type of spring element, that is attached to
the blade guard 12 and the corresponding holding means end 22a at
corresponding spring attachments 45a, 45b. A first imaginary line
46 passing the spring attachments 45a, 45b passes a second
imaginary line 47 when brought to the second position. The second
line 47 is parallel to the first line 46 and runs via the pivot pin
13, such that the cover part 11 is spring-biased towards the second
position along a part of the path. In other words, as illustrated
in FIG. 17A and FIG. 17B, a distance D, E between the lines 46, 47
changes sign. This means that the cover part 11 mainly is
spring-biased towards the first position, but also is spring-biased
towards the second position in the vicinity of the second position.
This means that the cover part 11 can be fixedly set in the second
position, but easily be brought back to the first position by
moving it slightly away from the second position and then letting
the spring force act. This is illustrated in FIG. 18 and FIG. 19
which mainly correspond to FIG. 4 and FIG. 3. FIG. 18 and FIG. 19
are also used for illustrating a further example of the present
disclosure as will be discussed later.
[0119] According to some aspects, for all the examples described
above, there is arranged an additional corresponding spring element
attached to an additional corresponding holding rod end on the
other side of the blade guard arrangement 8, not shown in FIG.
1-FIG. 4, FIG. 12A, FIG. 12B, FIG. 13, FIG. 16, FIG. 17A, FIG. 17B,
FIG. 18 and FIG. 19.
[0120] In FIG. 5 that corresponds to FIG. 3, another example is
shown. Here, the spring element 33, 41 is covered by a covering
plate 31. The covering plate is according to some aspects adapted
to receive an incoming water supply hose 49, and thus also adapted
to cover or comprise water dispensing means (not shown) adapted to
dispense 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 other side of the blade guard
arrangement as well, possibly adapted to cover or comprise water
dispensing means, not shown in FIG. 5.
[0121] With renewed reference to FIG. 1 and FIG. 2, the second
holding rod 22 also constitutes a continuously running delimiting
contact part against which a work object 18 at least partly can
rest during cutting of the work object 18. During cutting, the
cover part 11 can move between the first position and the second
position by means of pressure from the work object 18 against the
contact part of the second holding rod 22, where this pressure
works against the biasing. In this manner, the work object 18 will
not be caught or stuck anywhere while pressing against the contact
part and moving the cover part 11 between the first position and
the second position. In order to further facilitate this, according
to some aspects, the cover part 11 comprises a wheel 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 the wheel 25 that is adapted to be in
rotatable contact with a work object 18 during cutting.
[0122] In the following, a number of examples for alternative
attachments of the cover part 11 to the blade guard 12 will be
described with reference to FIG. 6-FIG. 11.
[0123] FIG. 6 shows a side view of a cutting disc 2 and a blade
guard arrangement 8' with a protective arrangement according to a
second example in the first position, and FIG. 7 shows a
corresponding side view in the second position.
[0124] Here, there are two holding arms 21', 22' attaching the
cover part 11' to the blade guard 12, where the holding arms 21',
22' are positioned at the same side of the blade guard arrangement
8. The holding means 21', 22' lie in different planes parallel to a
planar extension of the cutting disc 2. This means that straight
first holding arm 21' is sandwiched 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 part according
to the above, i.e. a continuously running delimiting contact part
against which a work object 18 at least partly can rest during
cutting of the work object 18.
[0125] According to some aspects, there are arranged additional
holding arms corresponding to the holding arms 21', 22' on the
other side of the blade guard arrangement 8', which holding arms
are not showed in FIG. 6 and FIG. 7.
[0126] FIG. 8 shows a side view of a cutting disc 2 and a blade
guard arrangement 8'' with a protective arrangement according to a
third example in the first position, and FIG. 9 shows a
corresponding side view in the second position.
[0127] Here, the cover part 11'' is attached to the blade guard
12'' by means of a holding pin 37 comprised in the blade guard
arrangement 8''. The holding pin 37 is in the form of a guide
attached to the blade guard 12'' and is adapted to run in a
corresponding arcuate slot 38 in the cover part 11''. According to
some aspects, there is an additional corresponding holding pin and
slot on the other side of the blade guard arrangement 8'', not
shown in FIG. 8 and FIG. 9.
[0128] The cover part 11'' has a somewhat pie-shaped structure in
this example and comprises a front edge 36 that constitutes a
contact part according to the above, i.e. a continuously running
delimiting contact part against which a work object 18 at least
partly can rest during cutting of the work object 18. The front
edge 36 runs on both sides of the cutting disc 2.
[0129] FIG. 10 shows a side view of a cutting disc 2 and a blade
guard arrangement 8''' with a protective arrangement according to a
fourth example in the first position, and FIG. 11 shows a
corresponding side view in the second position.
[0130] Here, the cover part 11''' is attached to the blade guard
12''' by means of at least one pivot 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 pivot pin is slightly offset from the center 16.
According to some aspects, there is an additional corresponding
pivot pin on the other side of the blade guard arrangement 8''',
not shown in FIG. 10 and FIG. 11.
[0131] According to some aspects, the examples described with
reference to FIG. 8-11 can be combined such that the cover part
11'' is attached to the blade guard 12'' by means of a holding pin
37 comprised in the blade guard arrangement 8'' and is adapted to
run in 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 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.
[0132] The cover part 11''' that has a somewhat pie-shaped
structure in this example and comprises a front edge 40 that
constitutes a contact part according to the above, i.e. a
continuously running delimiting contact part against which a work
object 18 at least partly can rest during cutting of the work
object 18. The front edge 40 runs on both sides of the cutting disc
2.
[0133] According to some aspects, for the examples discussed with
reference to FIG. 6-FIG. 11, the cover part is spring biased by one
or more spring elements; where applicable by means of spring
elements similar to the ones as discussed previously.
[0134] 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 the first position and the
second position. Optionally, as only shown in FIG. 1, the blade
guard 12 comprises a lock part 48 that is adapted for releasably
locking the cover part 11 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.
[0135] 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 for example 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 or holes.
[0136] In the following, an alternative protective arrangement will
be described for the hand-held power cutter 1 with reference to
FIG. 14 and FIG. 15, constituting a fifth example. The previously
described second position is here a working position, as shown in
FIG. 14, and the previously described first position is here a
displaced position, as shown in FIG. 15.
[0137] The blade guard arrangement 8a comprises a blade guard 12
and a protective arrangement 23 that is adapted to be displaced
from a working position, where the protective arrangement 23 admits
normal cutting of a work object 18, to a displaced position such
that the protective arrangement 23 in the displaced position at
least partly becomes 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 the blade
guard 12 in the direction of rotation 19.
[0138] According to some aspects, the displacement is caused by the
mass of the protective arrangement in combination with an
acceleration, and can for example be initiated by means of a
kick-back condition.
[0139] In this example, the blade guard 12 comprises a protective
part 23 that constitutes the protective arrangement, where the
blade guard 12 is adapted to rotate around the center 16 in the
direction of rotation 19 should an acceleration according to the
above occur. According to some aspects, the protective part 23
comprises a weight 24, and thus the blade guard 12 also comprises
the weight 24.
[0140] The moveable blade guard can suitably be rotated in any
direction around the center 16 by hand as well, and in that case by
means of a handle 50.
[0141] For this alternative, the protective part can instead, or as
a complement, comprise the cover part 11, 11', 11'', 11''' as
discussed previously, as illustrated for a blade guard arrangement
8b in FIG. 18 and FIG. 19. FIG. 18 shows side view of a cutting
disc and a blade guard arrangement with a protective arrangement
being biased towards the working position by means of the second
type of spring element and FIG. 19 shows a corresponding side view
with a protective arrangement being biased towards the displaced
position by means of the second type of spring element.
[0142] This means that the swiveling cover part 11 is spring-biased
by means of a spring element 41 that is attached to the blade guard
12 and a corresponding holding means end 22a, and where the holding
means end 22a is attached 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 working position along a part of the path and
towards the displaced position along the rest of the path, where
said part of the path is shorter than the rest of the path. This
allows the cover part 11 to be held in the working position while
working, and to be quickly displaced to the displaced position
should an acceleration according to the above occur.
[0143] A biasing means as previously described with reference to
FIG. 16 is also conceivable since it achieves this desired
functionality.
[0144] Furthermore, with reference to FIG. 20 and FIG. 21,
according to some aspects, the blade guard arrangement 8c, 8d
comprises a protective arrangement that in turn comprises an airbag
29, 32 that is adapted to be inflated and expand to the displaced
position.
[0145] In FIG. 20 there is a blade guard arrangement 8c that
comprises an airbag generator 51 from which an airbag 28 has been
deployed, covering a certain arc A2 of a circle. Here, the airbag
28 is intended as a protection as well as a brake, the airbag 28
being adapted to expand from the blade guard 12 and to partly be
positioned between the circumference 17 and the blade guard 12
after inflation, such that the movement of the rotatable work tool
2 is reduced.
[0146] In FIG. 21, there is a blade guard arrangement 8d that
comprises an airbag generator 52 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.
[0147] In these alternative cases, the protective arrangement 11,
23, 28, 29 mostly covers a part of the blade guard 12 in the
working position and is adapted to be displaced to the displaced
position along a path mostly following the direction of rotation
19.
[0148] The present disclosure is not limited to the above examples,
but may vary freely within the scope of the appended claims. For
example, there can be any type of power cutter with a rotatable
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 power cutter 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.
[0149] For all the examples discussed, according to some aspects,
the blade guard 12 is adapted 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 an
acceleration. For this purpose, according to some aspects, the
blade guard 12 comprises a weight 24.
[0150] The rod parts, arm parts, holding pins and pivot pins
described are all generally referred to as holding means. As
described, there can be one or more holding means.
[0151] According to some aspects, the circumference 17 can be
regarded as an imaginary circumference that follows an outer edge
of the rotatable work tool 2. The blade guard arrangement 8
comprises a blade guard 12 that is adapted to partly cover said
circumference 17.
[0152] The power cutter is generally constituted by a power tool
comprising a rotatable work tool.
[0153] According to some aspects, the protective arrangement
comprises a brake that is adapted to reduce the movement of the
rotatable work tool 2 during certain conditions.
[0154] Generally, the present disclosure relates to a hand-held
power tool 1 comprising a rotatable work tool 2 with a center 16
and a circumference 17 and being adapted to rotate in a certain
direction of rotation 19, where the power tool 1 further comprises
a blade guard arrangement 8 that is arranged to shield a variable
part of the rotatable work tool 2. The blade guard arrangement 8
comprises a blade guard 12 and 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, and, in a first position, the swiveling cover part
11, 11', 11'' is positioned such that a first arc A of a circle is
covered, where the first arc A 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, where the
cover part 11 is moveable between the first position and a second
position where a cutting operation of the rotatable work tool 2
along the first arc A of a circle is allowed, where the cover part
11, 11', 11'' is biased in the direction of rotation 19, towards
the first position by means of a biasing member.
[0155] Generally, the present disclosure also relates to a blade
guard arrangement 8 that is arranged to shield a variable part of a
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 adapted to partly cover said circumference
17. The blade guard arrangement 8 comprises 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, and, in a first position, is positioned such
that a first arc A of a circle is covered, where the first arc A of
a circle follows the blade guard 12, and runs an angular distance
along the circumference 17 after the blade guard 12, in an intended
direction of rotation 19 for the rotatable work tool 2, where the
cover part 11 is moveable between the first position and a second
position where a cutting operation of the rotatable work tool 2
along the first arc A of a circle is allowed, where the cover part
11, 11', 11'' is biased in the direction of rotation 19, towards
the first position by means of a biasing member.
[0156] According to some aspects, a second arc B of a circle is
adjacent to the first arc A of a circle and runs an angular
distance along the circumference 17 after the first arc A of a
circle in the direction of rotation 19, where the second arc B of a
circle is uncovered in the first position such that initial cutting
is allowed along the second arc B of a circle.
[0157] According to some aspects, the blade guard arrangement 8,
8', 8'', 8''' comprises a continuously running delimiting contact
part 22, 36, 40 against which a work object 18 at least partly can
rest during cutting of the work object 18, such that during
cutting, the cover part 11, 11', 11'', 11''' can move between the
first position and the second position by means of pressure from
the work object against said contact part 22, 36, 40, the pressure
working against the biasing, where the contact part either is
comprised in the cover part 11'', 11''' or comprised in a part 22,
22' connecting the cover part 11, 11' to the blade guard 12.
[0158] According to some aspects, each holding means 21, 22; 21',
22' at its respective ends being pivotably attached to the
swiveling cover part 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 second position.
[0159] According to some aspects, there are two holding means 21,
22 at the same side of the blade guard arrangement 8, where the
holding means lie 21, 22 in a common plane parallel to a planar
extension of the rotatable work tool 2.
[0160] According to some aspects, there are two holding means 21',
22' at the same side of the blade guard arrangement 8, where the
holding means 21', 22' lie in different planes parallel to a planar
extension of the rotatable work tool 2.
[0161] According to some aspects, the cover part 11'' is attached
to the blade guard 12'' by means of at least one holding means 37
comprised in the blade guard arrangement 8'', each holding means 37
being in the form of a guide attached to the blade guard 12'' and
being adapted to run in a corresponding arcuate slot 38 in the
cover part 11''.
[0162] According to some aspects, the cover part 11''' is attached
to the blade guard 12''' by means 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 guard
12''' where the cover part 11''' is adapted to pivot around the
pivot pin 39.
[0163] According to some aspects, the cover part 11, 11', 11'',
11''' is connected to the blade guard 12 such that it is moveable
along a path between the first position and the second position,
where the path mainly follows the circumference 17 such that a part
of the blade guard 12 is radially positioned between the
circumference 17 and the cover part 11, 11', 11'', 11''' in the
second position.
[0164] According to some aspects, the swiveling cover part 11, 11',
11'' 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, 41 that constitutes said biasing
means.
[0165] According to some aspects, each spring element 33, 41 is
attached to the blade guard 12 and a corresponding holding means
end 22a and where the holding means end 22a is attached to the
blade guard 12 by means of a pivot pin 13, the spring element being
biased such that the cover part 11 strives towards the first
position along at least a part of the path.
[0166] According to some aspects, the spring element 33 has a
winding part 34 and two arm parts 35 which are attached to the
blade guard 12 and the corresponding holding means end 22a at
corresponding arm attachments 42a, 42b, where a first line 43
passing the arm attachments 42a, 42b never passes a second line 44,
where the second line 44 is parallel to the first line 43 and runs
via the pivot pin 13, such that the cover part 11 is spring-biased
towards the first position along the path.
[0167] According to some aspects, the spring element 33 has a
winding part 34 and two arm parts 35 which are attached to the
blade guard 12 and the corresponding holding means 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 the second position, where the second line 44' is
parallel to the first line 43' and runs via the pivot pin 13, such
that the cover part 11 is spring-biased towards the second position
along a part of the path.
[0168] According to some aspects, the winding part 34 is adapted to
move when the cover part 11 is moved between the first position and
the second position such that the force needed to move the cover
part 11, 11', 11'' is reduced from the first position to the second
position.
[0169] According to some aspects, the spring element 41 comprises a
spiral spring that is attached to the blade guard 12 and the
corresponding holding means end 22a at corresponding spring
attachments 45a, 45b, where a first line 46 passing the spring
attachments 45a, 45b passes a second line 47 when brought to the
second position, where the second line 47 is parallel to the first
line 46 and runs via the pivot pin 13, such that the cover part 11
is spring-biased towards the second position along a part of the
path.
[0170] According to some aspects, the cover part 11 comprises a
handle 30 that admits a user to move the cover part 11 between the
first position and the second position.
[0171] According to some aspects, the blade guard 12 comprises a
lock part 48 that is adapted for releasably locking the cover part
11 in the second position.
[0172] According to some aspects, the blade guard 12 is adapted to
rotate in the direction of rotation 19, where the rotation is
caused by the mass of the blade guard 12 in combination with an
acceleration.
[0173] According to some aspects, the blade guard 12 comprises a
weight 24.
[0174] According to some aspects, the cover part 11 comprises a
wheel 25 that is adapted to be in rotatable contact with a work
object 18 during cutting.
[0175] According to some aspects, the cover part 11 at least partly
is made as a see-through structure.
[0176] Generally, the present disclosure also relates to a
hand-held power tool 1 comprising a rotatable work tool 2 having a
center 16 and a circumference 17 and being adapted to rotate in a
certain direction of 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 work tool 2.
The blade guard arrangement 8 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 such that the protective arrangement 11, 23, 28,
29 in the displaced position 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.
[0177] Generally, the present disclosure also relates to a blade
guard arrangement 8 that is arranged to shield a variable part of a
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 adapted to partly cover said circumference
17. The blade guard arrangement 8 comprises 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
is adapted to admit normal cutting of a work object 18, to a
displaced position such that the protective arrangement 11, 23, 28,
29 in the displaced position 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 an intended direction of rotation 19 for the rotatable
work tool 2,
[0178] According to some aspects, the displacement is caused by the
mass of the protective arrangement in combination with an
acceleration.
[0179] According to some aspects, the blade guard 12 comprises a
protective part 23 that constitutes the protective arrangement,
where the blade guard 12 is adapted to rotate around the center 16
in the direction of rotation 19.
[0180] According to some aspects, the protective part 23 comprises
a weight 24.
[0181] According to some aspects, the protective arrangement 11,
23, 28, 29 mostly covers a part of the blade guard 12 in the
working position and is adapted to be displaced to the displaced
position along a path mostly following the direction of rotation
19.
[0182] 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
holding means 21, 22; 21', 22' at its respective ends being
pivotably attached to the swiveling cover part 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
second position.
[0183] According to some aspects, there are two holding means 21,
22 at the same side of the blade guard arrangement 8, where the
holding means lie 21, 22 in a common plane parallel to a planar
extension of the rotatable work tool 2.
[0184] According to some aspects, there are two holding means 21',
22' at the same side of the blade guard arrangement 8, where the
holding means 21', 22' lie in different planes parallel to a planar
extension of the rotatable work tool 2.
[0185] According to some aspects, the cover part 11'' is attached
to the blade guard 12'' by means of at least one holding means 37
comprised in the blade guard arrangement 8'', each holding means 37
being in the form of a guide attached to the blade guard 12'' and
being adapted to run in a corresponding arcuate slot 38 in the
cover part 11''.
[0186] According to some aspects, the cover part 11''' is attached
to the blade guard 12''' by means 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 guard
12''' where the cover part 11''' is adapted to pivot around the
pivot pin 39.
[0187] According to some aspects, the cover part 11, 11', 11'',
11''' is connected to the blade guard 12 such that it is moveable
along a path between the first position and the second position,
where the path mainly follows the circumference 17 such that a part
of the blade guard 12 is radially positioned between the
circumference 17 and the cover part 11, 11', 11'' in the second
position.
[0188] According to some aspects, the swiveling cover part 11 is
spring-biased by means of at least one spring element 33, 41, where
each spring element 33, 41 is attached to the blade guard 12 and a
corresponding holding means end 22a and where the holding means end
22a is attached to the blade guard 12 by means of a pivot pin 13,
the spring element 33, 41 being biased such that the cover part 11
strives towards the working position along a part of the path and
towards the displaced position along the rest of the path.
[0189] According to some aspects, the spring element 33 has a
winding part 34 and two arm parts 35 which are attached to the
blade guard 12 and the corresponding holding means 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 the working position, where the second line 44' is
parallel to the first line 43' and runs via the pivot pin 13.
[0190] According to some aspects, the winding part 34 is adapted to
move when the cover part 11 is moved between the working position
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.
[0191] According to some aspects, the spring element 41 comprises a
spiral spring that is attached to the blade guard 12 and the
corresponding holding means end 22a at corresponding spring
attachments 45a, 45b, where a first line 46 passing the spring
attachments 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.
[0192] According to some aspects, the protective arrangement
comprises an airbag 28, 29 that is adapted to be inflated and
expand to the displaced position.
[0193] According to some aspects, the airbag 28 is adapted expand
from the blade guard 12 and to partly be positioned between the
circumference 17 and the blade guard 12 after inflation, such that
the movement of the rotatable work tool 2 is reduced.
* * * * *