Hand tools abstract
Guards for covering rotating discs of power hand tools wherein
said guard includes a movable guard for covering a normally exposed
portion of a disc and which is pivotably mounted relative to a body
of the power tool such that the it is movable from a first covering
position in a plane substantially parallel to a rotational plane
of the disc to a second withdrawn position in which the movable
guard extends generally transversely to the rotational plane of
the disc thereby allowing maximum disc coverage yet permitting disc
use in restricted spaces.
Hand tools claims
1. A method of providing protection by way of a guard covering
a portion of a rotary disc of a hand held power tool wherein the
power tool includes a body from which extends a rotating disc, the
method comprising: a) providing a movable guard, b) providing a
mounting member for securing the movable guard relative to the body
of the power tool; c) pivotally mounting the movable guard relative
to the mounting member so as to be movable from a first position
extending generally parallel to a rotational plane of the rotating
disc and intermediate the rotating disc and the body of the power
tool to a second position wherein the movable guard extends transverse
to the rotational plane of the rotating disc; and d) resiliently
urging the movable guard toward the first position.
2. The method of claim 1 including the additional step of frictionally
retaining the movable guard in the first position.
3. A guard apparatus for use with a hand held rotary power tool
having a body from which extends a rotating disc, the apparatus
including, a movable guard, mounting means for mounting the movable
guard to the body of the tool, pivot means for pivotally mounting
the movable guard relative to said mounting means so as to be movable
from a first covering position adjacent the rotating disc and extending
generally parallel to a rotational plane of the rotating disc to
a second retracted position extending transversely with respect
to the rotational plane of the rotating disc, and resilient means
for resiliently urging said movable guard toward said first position.
4. The apparatus of claim 3 including a fixed guard, and second
mounting means for mounting said fixed guard in covering relationship
intermediate the rotating disc of the power tool and the body thereof
such that said fixed guard extends between a first portion of the
rotating disc and the body of the tool and the movable guard extends
between a second portion of the rotating disc and the body of the
5. The apparatus of claim 4 in which said pivot means includes
pivot assemblies for securing said movable guard to said mounting
means, each of said pivot assemblies including a resilient means
including a spring mounted for pivotally urging said movable guard
toward said first position.
6. The apparatus of claim 4 including a friction lock for normally
retaining said movable guard in said first position.
7. The apparatus of claim 3 wherein said movable guard is formed
of a transparent material.
8. The apparatus of claim 3 including a fixed guard, extending
intermediate a portion of the rotating disc of the power tool and
the body thereof such that said fixed guard and said movable guard
extend between separate portions of the rotating disc and the body
of the power tool.
9. The apparatus of claim 8 in which said fixed guard is mounted
to said mounting means.
10. The apparatus of claim 9 including means for urging said movable
guard toward said first position.
11. The apparatus of claim 10 in which each of said fixed guard
and said movable guard have outer extending flanges for covering
an outer peripheral edge of the rotating disc of the power tool.
12. The apparatus of claim 8 in which said fixed guard is mounted
to said mounting means and said movable guard is pivotally mounted
to said fixed guard.
13. The apparatus of claim 12 in which said movable guard has an
inner edge cut out to provide a clearance for said movable guard
relative to said mounting means.
14. The apparatus of claim 3 in which said movable guard has an
inner edge cut out to provide a clearance for said movable guard
relative to said mounting means.
15. The apparatus of claim 3 including means for continuously urging
said movable guard to said first position.
16. An apparatus for providing a guard for a hand held power tool
having a body and a rotating disc, the apparatus comprising, a guard
including a movable guard section and a fixed guard section, mounting
means for mounting said fixed guard section to the body of the tool
such that said movable guard section and fixed guard section extend
outwardly between the rotating disc and the body of the power tool,
pivot means for pivotally connecting said movable guard section
to said fixed guard section whereby said movable guard section is
movable from a first position extending generally parallel to a
rotational plane of the rotating disc of the power tool to a second
position extending transversely thereto, and urging means for resiliently
urging the movable guard section toward said first position.
17. The apparatus of claim 16 in which said movable guard section
has an inner edge having a cut out to provide a clearance for said
movable guard section relative to said mounting means.
18. The apparatus of claim 17 in which said pivot means for pivotally
mounting includes at least one hinge member mounted on said fixed
guard section and said movable guard section.
19. The apparatus of claim 18 in which said movable guard section
20. The apparatus of claim 19 in which said fixed guard section
Hand tools description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is generally directed to safety guards for use with
power hand tools and especially those such as rotary grinders and
sanders incorporating a rotating disc. More particularly, the present
invention is directed to movable guards which are pivotable relative
to a rotating disc of a power hand tool for purposes of providing
a safety barrier to prevent injury, both by accidental contact with
the rotating disc and also due to debris being thrown beyond the
2. Brief Description of the Related Art
Heretofore there have been many innovations made with respect to
providing safety guards for use with hand held power tools which
incorporate rotating mechanisms such as sanders, edgers, planars,
grinders and the like. Generally, such guards fall into one of two
categories. The first type of guard is designed to protectively
cover at least a portion of either side of a rotating tool, such
as a sander or grinder, such that the guard has opposite sidewalls
which extend in parallel relationship with respect to one another
on either side of a segment of the disc. The guards are mounted
to enclose a portion of the tool disc but must leave a portion of
the disc exposed for allowing an edge of the disc to engage a work
surface. With some such guards, the guard housing is fixed, however,
in others, the guard housing may include a segment which can be
pivotable about an axis which is generally parallel to a rotational
axis of the disc thereby allowing the guard to move by engagement
with a surface, so as to pivot away from the surface and expose
an edge portion of the disc.
Some examples of the first type of guard are disclosed in U.S.
Pat. Nos. 2384243 to Flohr et al., 3969856 to Zerrer, 3585980
to Mellor, 4711055 to Mickos, 5033192 to Franz and 5140754
Of the foregoing safety devices, each is designed to be mounted
so as to at least partially enclose a rotating disc such that a
section of an edge of the disc may be used to engage a work surface.
In each of these patents, it is generally the radial edge of the
disc which is the working portion of the tool.
In U.S. Pat. Nos. 3585980 and 5033192 the protective guards
or hoods are generally designed to be fixed relative to the rotating
tool and provide exit or exhaust openings for guiding material to
an appropriate collection device. The guards with respect to these
mechanisms are not designed to completely cover the working surface
of the tool, and thus, a portion of the tool surface can be accidentally
In U.S. Pat. No. 5140754 the guard is designed to be pivoted
about the rotational axis of the tool. Again, it is generally the
radial edge of the tool which is the working component of the tool,
and even though the guard may be pivoted to allow different portions
of the tool surface to be covered, the surface of the tool remains
partially unprotected during tool use. A similar operating characteristic
is found in U.S. Pat. No. 3969856.
In U.S. Pat. Nos. 2384243 and 4711055 the guards provide a
complete enclosure for the rotating disc. Portions of the enclosure
are movable or pivotable about a central pivot axis in the event
the guard engages a work surface. With these structures, the rotating
disc remains within the confines of the guard until the guard engages
a surface at which time the guard pivots to allow exposure of a
radial edge of the disc. Unfortunately, such guards only find use
in specific type of tools wherein the radial edge of the tool is
the only working surface of the tool.
A second type of protective guard for rotating tools of the hand
held type includes a guard shield which extends in a plane which
is generally perpendicular to an elongated axis of a tool body so
as to be interposed in a plane parallel to the operating plane of
the working tool and the operator or a hand grip of the tool. Such
shielding guards normally are somewhat fixed structures which cover
only a segment or portion of the rotating disc, leaving a separate
section of the disc uncovered. These types of guards or shields
are more appropriately used for grinders and sanders wherein a planar
face of the grinder or sander, as well as a radial edge of the tool,
may be used on a work surface. Examples of these types of guards
are disclosed in U.S. Pat. No. 4330967 to Richardson and German
Patent DE 3940584A1.
Unfortunately, there remains a need to provide better protective
guards or shields for use with hand held rotary tools of the type
which have a working surface which may be a planar surface or a
radial edge of the tool, such as the case with many grinders and
rotary sanders. Further, there remains a need to provide such guards
which will, in many working positions of the tool, provide an effectively
complete cover or shield between the tool and an operator and yet
which will pivot to enable the tool to be used in hard to reach
areas which might otherwise be prohibited, if the guard or shield
remain fixed relative to the tool during its operation.
SUMMARY OF THE INVENTION
The present invention is directed to a pivotable guard assembly
which may be used in conjunction with conventional fixed guards
or may be incorporated with a fixed guard segment in order to provide
as much shielding protection to a tool operator as is possible when
using a powered rotating tool, such as a power sander or power grinder.
The invention incorporates a collar or mounting sleeve which can
be mounted along a front portion of a body of a hand held power
tool and secured thereto and to which is pivotably mounted a guard
or shield member. In preferred embodiments, the guard or shield
member is designed to extend, when in a first position, generally
parallel to a rotating disc of the tool so as to provide a barrier
over at least substantially half of the disc. The pivotable guard
or shield has an outer portion extending beyond the radial edge
of the disc and an inner portion which is contoured so as to allow
pivotable movement of the guard or the shield relative to the front
portion of the body of the power tool without interference therewith.
In this respect, the inner edge of the guard or shield will generally
be somewhat concavely configured to permit adequate clearance so
that the guard can be pivoted from its first position, in covering
relationship with respect to the tool disc, to a second fully withdrawn
position, wherein the guard or shield extends generally perpendicular
to a plane of rotation of the disc.
In a preferred embodiment, the pivotal guard is made of a transparent
material to allow the operator to view the working tool therethrough
to better control the use of the tool when working on a surface.
Also, in preferred embodiments, the manner in which the pivotal
guard or shield is mounted to the mounting collar is such as to
provide a resilient return of the pivotal guard or shield to its
first fully covering position. In this manner, the pivotal guard
will be automatically pivoted away from the working disc when the
pivotal guard engages a surface which would otherwise block the
disc from reaching a work surface to thereof allow contact of the
disc with the work surface. This is particularly the case when the
disc must be used in corner areas. As the disc approaches a corner,
the guard or shield will be pivoted toward the second position but
will resiliently return to its first covering position in the event
the tool is moved away from the closely confining space or area
in which the tool is being used, thus providing maximum safety and
coverage for the working disc which allows access to restricted
In another embodiment of the invention, a second generally fixed
guard or shield may be mounted directly to the tool body or to the
mounting collar by way of which the pivotal guard or shield is connected
to the work tool.
In yet another embodiment of the invention, the guard of the present
invention may include a first generally fixed section and a second
pivotal section which is pivotally mounted relative to the first
section such that the fixed and pivotal sections fully cover a rotating
disc when in a first position generally parallel relative to a rotary
place of the working disc. A pivot attachment between the pivotal
guard section and the fixed may be such that the pivotal guard section
is directly connected to the fixed guard section such as by resilient
hinges which permit the pivotal section to move from the first parallel
covering position toward and to a fully withdrawn position generally
perpendicular to the working or rotary plane of a disc. The hinges
automatically return the pivotal guard section to the fully covering
or first position as soon as the tool is removed from a restricted
work space. In some embodiments, both the fixed and the pivotal
guard sections may be transparent and in some embodiments, one or
more of the guard sections may include outwardly extending flanges
for providing further protection along the rachet edge portion of
Also, in some embodiments, a friction locking mechanism may be
provided so as to normally retain the pivotal section of the guard
or shield in its first position until sufficient pressure is applied
to pivot the guard away from its fully covering position. Such friction
retention devices will provide added safety by ensuring that the
mere movement of the tool by the operator will not cause a pivotal
movement of the shield until the shield engages a surface which
is obstructing the use of the tool and which surface contact will
in effect provide the necessary force to overcome the friction lock
and cause the pivotal movement of the pivotal section of the guard
It is a primary object of the present invention to provide a safety
guard or shield for use with hand held rotary power tools, such
as power grinders and power sanders, wherein the guard includes
at least one pivotable component which is generally resiliently
loaded to maintain the guard section in a fully covering position
in a plane extending generally parallel to a tool disc and between
a plane of the disc and the handle of the tool but which is pivotal
away to allow the tool disc to engage hard to reach areas so that
the guard shield does not provide an obstruction prohibiting the
normal use of the disc of the power tool.
It is yet a further object of the present invention to provide
a safety guard or shield for use with power grinders and power sanders,
as well as other power tools having rotary discs wherein at least
a portion of the guard or shield is transparent so as to allow an
operator to view the working tool and a work surface therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the invention will be had with respect
to the attached drawings wherein:
FIG. 1 is a perspective illustrational view of the invention showing
the guard attached to a hand held power grinder with a pivotal section
of the guard shown in a fully withdrawn or retracted position permitting
the use of the power tool in hard to reach areas;
FIG. 2 is an elevational view of the embodiment as shown in FIG.
FIG. 3 is an elevational view similar to FIG. 2 but showing the
pivotal guard section pivoted to a first fully covering relationship
with respect to the rotating disc of the power tool;
FIG. 4 is a top perspective view of a second embodiment of guard
in accordance with the teachings of the present invention;
FIG. 5 is a view similar to FIG. 4 except showing a pivotal section
of the guard raised or pivoted to a second non-obstructing position;
FIG. 6 is a bottom perspective view of the embodiment shown in
FIG. 7 is an enlarged cross-sectional view taken along line 7--7
of FIG. 4; and
FIG. 8 is a perspective view of a further embodiment of the present
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With continued reference to the drawing figures, a power tool 20
of the hand held type is shown having a pistol grip handle 21 an
operating on/off trigger 22 a main body 23 and a rotating tool
disc 24. The tool disc rotates about an axis "A--A" as
shown in FIG. 1. The power tool may be any type, such as a rotary
grinder or sander. The tool disc generally has a planar working
front face 25 and a radial working annular edge 26.
As shown in FIGS. 1-3 in some conventional tools, a partial fixed
guard 30 is provided which extends over approximately half of the
rotating disc. Such conventional guards are generally mounted to
the body of the power tool utilizing a collar or clamp 31 having
opposing flanges 32 and 33 which are secured by appropriate fasteners
such as a screw 34. The clamp is mounted directly to a forward portion
of the body of the tool such that the guard 30 is disposed generally
parallel between the disc and the pistol grip or operating portion
of the power tool. In this position, the conventional fixed guard
30 covers a portion of the disc to prevent contact over approximately
half of the working portion of the disc and to prevent debris from
being thrown back toward the operator. However, with such conventional
guards, a substantial portion of the disc remains unprotected. The
conventional guards are generally formed of a metallic material
and may include a lip portion 37 for extending along a peripheral
edge of the disc.
In accordance with a first embodiment of the present invention,
a second pivotal or movable guard or shield 40 is shown as being
pivotally mounted to a collar or sleeve 41. The collar generally
surrounds the forward portion of the power tool just rearwardly
of the position at which the clamp for the fixed guard is mounted.
The collar may include separate sections or may include a single
piece which is cast, hollowed or bored to provide an appropriate
seat. The collar or sleeve is secured in place using a plurality
of set screws 43 or other securing devices, such that the collar
or sleeve will not move relative to the tool body when in use.
In the embodiment of FIGS. 1-3 a pair of pivot blocks 46 and 47
are mounted to opposite sides of an extension portion 48 of the
mounting collar or sleeve. Mounting is accomplished by pivot pins
50 which are threadingly engaged, such as shown at 51 to the collar
but which permit the pivot blocks to be freely rotatable with respect
thereto, as shown in FIG. 7. Coil springs 52 are provided about
the shaft of the pivot pins, also as shown in FIG. 7 normally urging
the pivot blocks to the position shown in FIG. 3 of the drawings.
The pivotal guard or shield is secured by adhesive or by suitable
mechanical fasteners such as screws 54 to the two pivot blocks
such that the shield is securely retained to the blocks and moves
therewith about the pivot pins.
As shown in FIG. 7 in order to retain the pivotal guard or shield
in a first covering relationship with respect to a portion of the
disc which is not covered by the conventional guard 30 a friction
locking mechanism 60 is provided. Although various types of locking
mechanisms can be utilized, one example is shown in FIG. 7 wherein
a detent 65 is provided in at least one outer surface of the extension
portion 48 of the sleeve in which a detent ball 62 is normally seated
when the pivotal guard is in a position as shown in FIG. 3. A spring
63 is mounted within a passageway 64 formed in the pivot block 46
and the sleeve is retained in position by a set screw 66. In this
manner, the detent ball will normally be seated within the detent
and retain the pivots blocks in the position shown in FIG. 3 under
normal operating conditions. A similar lock may be used with pivot
block 47. The amount of locking force can be adjusted by adjusting
the set screw associated therewith.
In the event the pivotal or movable guard 40 engages a surface,
the pivotal guard can pivot about the pivot pins 50 when the force
supplied to the guard is sufficient to urge the locking balls from
the detents, thus permitting the movable guard to freely rotate
with the pivot blocks such that the guard moves to a fully retracted
or second position, as is shown in FIGS. 1 and 3 transverse to
the rotational plane "R" of the disc. As shown, the movable
guard is generally perpendicular to the plane "R" in FIG.
3. In this position, the disc of the tool may be free to work in
areas which would be hard to reach and could not be reached with
the movable guard in its first or covered position, as shown in
FIG. 3 wherein the movable guard is generally parallel to the rotational
plane "R" of the disc.
Due to the spring mounting of the pivot blocks relative to the
collar, as soon as the obstruction is removed relative to the pivotal
guard or shield, the guard will automatically return to the first
position shown in FIG. 2 under the force of the springs 52 thus
ensuring optimum coverage of the tool disc during operating conditions.
To permit the relative rotation of the pivotal guard relative to
the tool disc and to the collar, an inner edge 70 of the pivotal
guard is cut out as shown at 72 and may include a series of angular
cuts as shown at 73 and 74. These somewhat concave cuts provide
clearance for the guard adjacent to the extension portion of the
collar when in the first covering position as shown in FIG. 3. The
clearance provided by the cut out portion is further exemplified
or detailed in FIG. 5 which shows the pivotal guard in its fully
retracted or second position.
With respect to FIGS. 4-6 a second embodiment of the invention
is disclosed wherein the invention includes both a fixed guard component
80 which is similar in structure to the conventional guard segment
30 and a pivotal guard section 40 which is similar to the pivotal
guard section of the previous embodiment. The manner in which the
pivotal guard section 40 is pivotally mounted to the collar 41 is
identical to that as disclosed with respect to the previous embodiment.
However, in this embodiment, the fixed guard 80 can be attached
directly to the collar or sleeve 82 similar to sleeve 41 and thus
does not require a separate mounting clamp, as is disclosed with
respect to the conventional fixed guards 30 as shown in the embodiment
of FIGS. 1-3.
In both of the embodiments of FIGS. 1-3 and 4-6 the pivotal or
movable guard component is preferably constructed of a transparent
material such as a heavy duty plastic so that an operator may view
a work surface and the power tool disc through the guard or shield.
This is important not only to allow the operator to know the relative
position of the pivotal guard and the working tool but also to allow
the operator to view the effect of the working disc on a work surface.
In some embodiments, the stationary or fixed guard segment 80 may
also be transparent.
In both of the embodiments previously described, it should be noted
that the pivotal guard component is shown as a generally flat or
planar component. It should be noted that the outer edge of this
member may include a flange or lip similar to that formed on the
outer edge of the conventional guard 30 shown at 37. Further, the
pivotal guard or shield extends outwardly a distance beyond the
radial annular work edge of the rotary disc of the power tool.
With respect to FIG. 8 a further embodiment of the invention is
shown in greater detail. In this embodiment, the guard 100 includes
a pivotal section 101 which is connected to a fixed or stationary
section 102 by way of a pair of spring hinges 103 and 104. A central
mounting collar 105 is connected to the fixed guard or shield section
and includes a locking member, such as a screw, for clamping the
collar to a portion of a power tool in a manner similar to the manner
in which conventional fixed guards are mounted and as shown in FIGS.
1-3. In this embodiment, the hinges are shown incorporating springs
106 which are designed to force or urge the pivotal guard section
101 to the position shown in FIG. 8 which is the first covering
position of the pivotal guard. When the pivotal guard engages an
obstruction, it can be pivoted against the action of the springs
and pivot outwardly to a second position generally perpendicular
with respect to a rotational plane "R" of the tool disc,
in a manner similar to that described and shown with respect to
the embodiment of FIGS. 1 and 3. As soon as any obstructed force
is removed, the pivotal guard section will be allowed to return
the position shown in FIG. 8 by action of the springs associated
with the hinges.
In this embodiment, both the fixed and the pivotal guard segments
are made of transparent plastic material. Further, a cut out 110
of generally concave shape is provided in the pivotal guard segment
for purposes of providing clearance for the guard segment relative
to the mounting collar 105. Further, in this embodiment, each of
the fixed and the pivotal guard sections is provided with an outer
flange or lip 108 and 109 which extends outwardly beyond the annular
edge of the working disc, thus providing further safety for the
operator of the power tool.
In the use of the various embodiments of the present invention,
the mounting collar or sleeve is first positioned on the body of
the power tool and mechanically secured in position. In those embodiments
where a conventional fixed guard is used, the fixed guard must be
removed before placing the collar or sleeve into position unless
a split collar or sleeve is used. In some embodiments, although
not shown in the drawings, the collars or sleeves may be used as
split sleeves which may be secured in half sections to one another
and clamped to the body of the tool.
With the collars in place, the fixed guard and the pivotal guard
will ensure a complete barrier or shield between the working disc
and the operator, as is shown in FIG. 2. In the event an obstruction
is encountered, the pivotal guard section will be forced from its
first covering position, as shown in FIG. 2 to a fully retracted
position, as shown in FIGS. 1 and 3 thereby permitting the working
disc to function in restricted areas. Due to the resilient mounting
of the pivotal guard or shield, once the power tool is removed from
the obstructed area, the pivotal guard or shield will be automatically
returned to its fully covering position to provide maximum safety
for the operator.
In addition to the foregoing, as previously discussed, in some
embodiments, a separate locking means, such as a friction detent
lock, or other lock, can be utilized to secure the pivotal shield
in its first covering position such that the shield can not be accidentally
moved away from the disc of the power tool by operator movement
of the tool but can only be moved when an obstruction is encountered.
The foregoing description of the preferred embodiment of the invention
has been presented to illustrate the principles of the invention
and not to limit the invention to the particular embodiment illustrated.
It is intended that the scope of the invention be defined by all
of the embodiments encompassed within the following claims and their