U.S. patent application number 11/238494 was filed with the patent office on 2006-03-30 for cover device for a power tool.
This patent application is currently assigned to Hilti Aktiengesellschaft. Invention is credited to Alexander Funk, Christian Koschel.
Application Number | 20060068690 11/238494 |
Document ID | / |
Family ID | 35241005 |
Filed Date | 2006-03-30 |
United States Patent
Application |
20060068690 |
Kind Code |
A1 |
Koschel; Christian ; et
al. |
March 30, 2006 |
Cover device for a power tool
Abstract
A cover device for partially covering a front, in an axial
direction, side of a disc-shaped working tool (10) of a power tool
includes a bearing element (22) securable on the shielding member
(12), which partially radially covers the working tool (10), and
having a bearing surface (28) abutting, at least regionwise, an
outer surface (14) of the shielding member (12), a protective disc
(30) extending substantially transverse to the bearing surface (28)
of the bearing means (22), and engaging-from-behind elements (24)
provided at opposite tangential ends of the bearing surface (28),
respectively, with at least one of the engaging-from-behind
elements (24) being elastically pivotal in a radial direction.
Inventors: |
Koschel; Christian;
(Augsburg, DE) ; Funk; Alexander; (Schwabmuenchen,
DE) |
Correspondence
Address: |
ABELMAN, FRAYNE & SCHWAB
666 THIRD AVENUE, 10TH FLOOR
NEW YORK
NY
10017
US
|
Assignee: |
Hilti Aktiengesellschaft
|
Family ID: |
35241005 |
Appl. No.: |
11/238494 |
Filed: |
September 28, 2005 |
Current U.S.
Class: |
451/451 |
Current CPC
Class: |
B24B 55/052
20130101 |
Class at
Publication: |
451/451 |
International
Class: |
B24B 55/04 20060101
B24B055/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2004 |
DE |
10 2004 047 278.5 |
Claims
1. A cover device for partially covering a front, in an axial
direction, side of a disc-shaped working tool (10) of a power tool
having a shielding member (12) that partially radially covers the
working tool (10), the cover device comprising: bearing means (22)
securable on the shielding member (12) and having a bearing surface
(28) abutting, at least regionwise, an outer surface (14) of the
shielding member (12); a protective disc (30) extending
substantially transverse to the bearing surface (28) of the bearing
means (22); and engaging-from-behind elements (24) provided at
opposite tangential ends of the bearing surface (28), respectively,
at least one of the engaging-from-behind elements (24) being
elastically pivotal in a radial direction for changing a distance
(a) between the engaging-from-behind elements (24).
2. A cover device according to claim 1, wherein the
engaging-from-behind elements (24) extend radially inward for
engaging from behind tangential limiting edges (26) of the bearing
surface (28) of the bearing means (22).
3. A cover device according to claim 1, wherein at least one of the
engaging-from-behind elements (24) is formed as a form-stable
hook-shaped element (32) connected with the bearing means (22), and
wherein the protective disc (30) is provided with a slot (34).
4. A cover device according to claim 1, further comprising an
elastically resilient locking element (40), and wherein at least
one of the engaging-from-behind elements (24) is provided on the
locking element (40).
5. A cover device according to claim 4, wherein the locking element
(40) has a spring arm (42) and a locking nose (38) provided on a
free end of the spring arm (42) and extending radially inward.
6. A cover device according to claim 5, wherein the spring arm (42)
is formed by two, extending parallel to each other, cut-ins (44)
provided on a tangential end of the bearing surface (28).
7. A cover device according to claim 1, wherein the cover device
(20), together with the engaging-from-behind elements (24), is
formed as a one-piece part.
8. A cover device according to claim 1, wherein the protective disc
(30) extends at least over a half-circle defined by the bearing
means (22).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a cover device for
partially covering a front, in an axial direction, side of a
disc-shaped grinding or separating tool of a power tool, in
particular, of an angle grinder. The cover device is designed in
particular to be retrofitted on the power tool. The cover device is
provided with a bearing member having a bearing surface securable,
when required, over a shielding member that partially covers the
working tool. The bearing surface at least regionwise abuts the
outer surface of the strip-shaped shielding member. The cover
device also includes a protective disc which extends substantially
transverse to the bearing surface and which partially covers the
front, in the axial direction, side of the working tool.
[0003] 2. Description of the Prior Art
[0004] Most of angle grinders are equipped, standardwise, with a
shielding member which is formed as a protective plate having an
acruate cross-section in the longitudinal direction and which is
secured to a truncated cone section provided on the power tool head
of the power tool. The shielding member partially covers the
working tool in the radial direction. With the power tool having
such shielding member, the power tool can be retrofitted, if
needed, in such a way that the working tool front side would be
partially covered in the axial direction. With the tool being
partially covered in the axial direction, the user becomes
effectively protected from accelerating material particles, in
particular sparks, also in the axial direction. On the other hand,
with the protective disc extending substantially transverse to the
bearing section, the cover means forms a space around the working
tool a major part of which is closed. The closed space insures an
effective suction of removable material particles.
[0005] The language "substantially transverse," which is used
above, means that the protective disc is arranged somewhat
transverse to the overall direction of the bearing surface
independent from the shape of the bearing surface of the bearing
means.
[0006] German document 94 03 777 discloses a cover device for an
angle grinder and which has a protective disc on which an
additional cover is pivotally supported. The disc has a jacket
element that partially extends over its circumference and that
surrounds the shielding member. The cover device is forcelockingly
secured on the angle grinder.
[0007] The known cover device covers the working tool well during
operation. However, the manufacturing costs of the device of DE 94
03 777 are relatively high. In addition, the means that provides
for the forcelocking connection of the cover device on the power
tool, such as, e.g., clamp screws, are either tedious to operate or
are not capable to absorb forces acting on the cover device during
the power tool operation, such as, e.g., tangentially acting
impacts, without the cover device being displaced.
[0008] An object of the present invention is to provide a cover
device in which the drawbacks of the known tool are eliminated.
[0009] Another object of the present invention is to provide a
cover device that can be produced with reduced manufacturing
costs.
[0010] A further object of the present invention is to provide a
cover device that can be rapidly mounted on or dismounted from the
power tool.
[0011] Yet a further object of the present invention is to provide
a cover device that would be reliably held on the power tool during
operation.
SUMMARY OF THE INVENTION
[0012] These and other objects of the present invention, which will
become apparent hereinafter, are achieved by providing
engaging-from-behind elements at opposite tangential ends of the
bearing surface, respectively, with at least one of the
engaging-from-behind elements being elastically pivotal, i.e.,
being pivotal with a recoverable deformation in a radial direction
for changing a distance a between the engaging-from-behind
elements.
[0013] The engaging-from-behind elements provide for a particularly
easy locking of the cover device with matching locking means, with
the distance between the engaging-from-behind elements being
increased by application of corresponding external forces. When the
cover device is mounted on the power tool, it can easily be pinned
on the shielding member, with the distance between the
engaging-from-behind elements assuming its initial value upon
removal of external forces as a result of action of restoring
forces which return the at least one engaging-from-behind element
to its initial position. Upon the distance between the
engaging-from-behind element returning to its initial value, they
become locked with the matching locking means of the power tool.
Upon release of the cover device, the engaging-from-behind elements
are displaced away from each other against the restoring force in
order to break the locking between the engaging-from-behind
elements and the matching locking means.
[0014] According to a particular advantageous embodiment of the
present invention, the engaging-from-behind elements extend
radially inward from tangential limiting edges of the bearing
surface of the bearing means. Thereby, formation of specific
matching means, e.g., in form of grooves or bores, on the shielding
member can be avoided, which minimizes manufacturing costs. In
addition, the cover device can be easily and rapidly pinned on the
power tool, with the engaging-from-behind elements engaging from
behind the limiting edges of the shielding member, securing the
cover device in both tangentional directions.
[0015] Advantageously, the at least on of the engaging-from-behind
elements is formed as a hook-shaped element securely connected with
the bearing means. In addition, the protective disc is provided
with a substantially radially extending slot. The slot gives the
cover device a certain elasticity, providing for displacement of
the engaging-from-behind elements away from each other under action
of external forces, with the elements being returned to their
initial position under the action of restoring forces. This makes
possible an easy mounting of the cover device on the power tool and
dismounting it therefrom without use of any assembly or other
tools.
[0016] Alternatively, the at least one engaging-from-behind element
can be formed on a spring-biased locking element. With the locking
element, the cover device can be particularly reliably secured on
the power tool.
[0017] Advantageously, the locking element has a spring arm, with a
locking nose being formed on a free end of the arm and extending
radially inwardly. The spring arm insures that the locking element
automatically engages from behind a respective limiting edge upon
mounting of the cover device on the power tool. Thereby, a
particularly easy connection of the cover device with the power
tool is insured.
[0018] Advantageously, the spring arm is formed by two, extending
parallel to each other, cut-ins provided at a tangential end of the
bearing surface. This insures a particularly cost-effective
manufacturing of the locking element.
[0019] Advantageously, the engaging-from-behind elements are formed
integrally with the remaining part of the cover device as a
one-piece part, i.e., by deformation or partial removal of the
material that forms the cover device. Thereby, manufacturing costs
are reduced, and a stable locking element is produced.
[0020] Advantageously, the protective disc extends at least over a
half-circle defined by the bearing means. Thereby, the working tool
can be covered particularly well in order to protect the user from
flying sparks and similar released and accelerated particles. Easy
mounting and dismounting of the cover device also insure a rapid
replacement of the working tool.
[0021] The novel features of the present invention, which are
considered as characteristic for the invention, are set forth in
the appended claims. The invention itself, however, both as to its
construction and its mode of operation, together with additional
advantages and objects thereof, will be best understood from the
following detailed description of preferred embodiments, when read
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings show:
[0023] FIG. 1 a perspective exploded view of a power tool with a
cover device according to the present invention;
[0024] FIG. 2 a perspective view of a cover device shown in FIG.
1;
[0025] FIG. 3a a side view of the cover device shown in FIG. 2;
[0026] FIG. 3b a cross-sectional view along line IIIb-IIIb in FIG.
3a;
[0027] FIG. 3c a detail IIIc in FIG. 3b at an increased, in
comparison with FIG. 3b, scale;
[0028] FIG. 4a a side view of another embodiment of a cover
device;
[0029] FIG. 4b a cross-sectional view along line IVb-IVb in FIG.
4a; and
[0030] FIG. 3c a detail IVc in FIG. 4b at an increased, in
comparison with FIG. 4b, scale.
DETAILED DESCRIPTION OF THE INVENTION
[0031] FIG. 1 shows a power tool 2 which is formed as an angle
grinder and has a housing 4 with a tool head 6. The tool head 6 has
a tool spindle 8 rotatable about an axis A and on which a
disc-shaped working tool 10 is secured. Further, there is provided
on the tool head 6 a shielding member 12 in form of a protective
plate that partially surrounds the working tool 10 in a radial
direction. The shielding member 12 has an outer surface 14 having
an arcuate cross-section in its longitudinal direction and a
straight section in its transverse direction and the edges of which
are rounded.
[0032] The working tool 10 is secured on the tool spindle 8 with a
tool retaining member 16. For mounting or dismounting the working
tool 10 on or from the tool spindle 8, the tool retaining member 16
is tightened or released, respectively, using an assembly tool 18
in form of, e.g., a wrench or, as shown in FIG. 1, in form of a
special tool.
[0033] FIG. 1 further shows a cover device 20 according to the
present invention in a position in which it is taken off the power
tool 2. The cover device 20 can be mounted on the shielding member
12 or dismounted therefrom without using any assembly tools. To
this end, the cover device 20 is provided with a strip-shaped
bearing means 22 the shape of which substantially corresponds to
the profile of the outer surface 14 of the shielding member 12.
[0034] The cover device 20 further includes inwardly projecting,
engaging-from-behind elements 24 which are provided, respectively,
at opposite tangential ends of the bearing means 22 and which are
spaced from each other by a distance a. Upon mounting of the cover
device 20 on the power tool 2, the bearing means 22 abuts the outer
surface 14 of the shielding member 12, and the engaging-from-behind
elements 24 contact the outer surface 14 that pushes the elements
24 away from each other. With the elements 24 being pushed away
from each other, the distance a therebetween increases. The outer
surface 14 is limited in the tangential direction at its opposite
ends by limiting edges 26 which are snapped behind by the
engaging-from-behind elements 24 due to the recovery forces
generated upon displacement of the elements 24 away from each
other.
[0035] As it is particularly shown in FIG. 2, the cover device 20
has, in a direction perpendicular to a section of a bearing surface
28 of the bearing means 22 which has a straight cross-section, a
protective disc 30. The protective disc 30 extends over a
semicircle defined by the bearing means 20 and covers, in the
mounted condition of the cover device 20 on the shielding member
12, in the axial direction, the frontal side of the working tool 10
toward outside, with the protective disc 30 projecting in the axial
direction partially beyond the tool spindle 8.
[0036] FIGS. 3a-3c shows a first embodiment of the
engaging-from-behind elements 24. The elements 24 have, at their
respective free ends, two hook-shaped elements 32 which are formed
at the tangential ends of the bearing means 22. The hook-shaped
elements 32, together with the engaging-from-behind elements 24,
are formed, together with the bearing means 22, as a substantially
formstable single piece. In order to be able to displace the
engaging-from-behind elements 24 away from each other to increase
the distance a therebetween for hooking the cover device 20 on the
limiting edges 26 of the shielding member 12 and for removing the
cover device 20 off the shielding member 12, there is formed, in
the protective disc 30, a radial slot 34. The slot 34 permits to
deform, the bearing means 22 during mounting of the cover device 20
on the shielding member 12 and dismounting of the cover device 20
from the shielding member 12. The slot 34 provides for a radial
pivotal movement of the engaging-from-behind elements 24, which
increases the distance a therebetween. By radially pivoting the
engaging-from-behind elements 24, it is possible to move them past
the limiting edges 26 in order to hook the elements on the limiting
edges 26 or to release the elements 24 from the limiting edges
26.
[0037] On the inner side of the hook-shaped elements 32, there is
formed a trough 36, as particularly shown in FIG. 3c, which
provides for a better holding of the hook-shaped elements 32 on
respective limiting edges 26 of the shielding member 12.
[0038] FIGS. 4a-4c show an alternative, second embodiment of the
engaging-from-behind elements 24. According to this embodiment, the
engaging-from-behind elements 24 are formed on a locking nose 38 of
an elastically resilient locking element 40. The locking element 40
has a spring arm 42 that is formed by two tangentional, extending
parallel to each other, cut-ins 44 provided at respective
tangential ends of the bearing means 22. The cut-ins 44 provide for
elastic pivotal movement of the engaging-from-behind elements 24 in
the radial direction relative to the bearing means 22 in order to
change the distance a therebetween.
[0039] With both embodiments of the engaging-from-behind elements
24, the cover device 20 can be rapidly pinned on the shielding
member 12, without using any additional tools.
[0040] In both embodiments, the engaging-from-behind elements 24
engage the limiting edges 26 in order to secure the cover device 20
on the shielding member 12 in the tangential and radial
direction.
[0041] Simultaneously, the cover device 20 is secured in the axial
direction with the partially arched bearing surface 28 the profile
of which corresponds to that of the outer surface 14 and which
substantially abuts the outer surface 14.
[0042] According to a further embodiment of the cover device 20,
only one engaging-from-behind element 24 is provided on the locking
element, whereas the other engaging-from-behind element is
connected with the bearing member 22 in a formstable manner. In
this case, upon mounting of the cover device 20, the
engaging-from-behind, form-stable element 24 should be hooked about
a respective limiting edge 26, and the cover device 20 should be
pivoted about this edge in order to have the other, elastic
engaging-from-behind element 24 snap from behind the other limiting
edge 26.
[0043] In the mounted condition of the cover device 20, the
protective disc 30 would cover the frontal side of the working tool
10 in the axial direction in order to protect the user better from
sparks which are generated during the operation of the power tool
and similar accelerating material particles.
[0044] In case the working tool 10 need be replaced, the cover
device can be rapidly removed, without using any tools, by lightly
disengaging the engaging-from-behind elements 24 from the shielding
member 12 in order to be able to engage the tool-retaining element
with the assembly tool 18.
[0045] Though the present invention was shown and described with
references to the preferred embodiments, such are merely
illustrative of the present invention and are not to be construed
as a limitation thereof and various modifications of the present
invention will be apparent to those skilled in the art. It is
therefore not intended that the present invention be limited to the
disclosed embodiments or details thereof, and the present invention
includes all variations and/or alternative embodiments within the
spirit and scope of the present invention as defined by the
appended claims.
* * * * *