[0001] This invention relates to drilling and or hammering tools, and especially to hammers
and rotary hammers, and to tool holders for use with such tools.
[0002] Such tools typically include a spindle that may be rotatably driven by means of a
motor, and a hammer mechanism, for example an air-cushion hammer mechanism, for repeatedly
striking a tool that is held by the hammer. The shank of a tool such as a drill bit
or chisel bit is held in the tool by means of a tool holder so that the tool can slide
axially in the tool holder by a few centimetres under the action of the hammer mechanism.
In one well known design, sold under the designation SDS Plus, the tool shank has
a pair of open-ended grooves for receiving splines in the tool holder for rotating
the tool, and a pair of closed-ended recesses for receiving locking elements in the
tool holder that limit the extent of axial movement of the tool in the tool holder.
The tool holder can be manually manipulated by the operator, for example by means
of axially slidable parts, in order to hold the tool therein and to release the tool
therefrom.
[0003] In addition, the tool holder itself often will need to be capable of being released
from the spindle in order to allow it to be changed, for example when a different
type of tool is to be held in the hammer. In this case the tool holder body or the
spindle is provided with one or more locking elements, for example locking balls,
that are movable in a radial direction (with respect to the axis of the spindle) to
retain the tool holder body on the spindle, or to allow release of the tool holder
body therefrom.
[0004] While the tool holder body is normally located around the external surface of the
spindle of the hammer, it has been proposed, for example in GB-A-2,313,566 (corresponding
to DE-A-196 21 610) and in US-A-5,437,465, for the tool holder body to be inserted
into the end of the spindle. Such designs have the advantage that the length of the
tool can be significantly reduced since the bore of the tool holder that receives
the tool shank, and the bore of the spindle may be allowed to overlap axially. In
the previous designs in which the tool holder was located around the exterior of the
spindle, the bore of the tool holder could only start at a position beyond the front
end of the spindle.
[0005] These designs of tool holder suffer from a number of disadvantages, however. For
example, with the tool holder described in GB-A-2,313,566, it can be difficult for
the user to find the correct axial orientation of the tool holder on the spindle in
order to lock the tool holder thereon, that is to say, it can be difficult to ensure
that the locking elements located on the spindle are in circumferential alignment
with corresponding elements on the tool holder for receiving them. In other cases,
axial movement of parts of the tool holder in order to release it from the spindle
can cause difficulties where axial movement of parts of the tool holder is required
to release or retain the tool shank in the tool holder. For example, where a ring
or skirt on the tool holder must be moved axially forwards to release it from the
spindle, the user will often grasp the tool holder along its axis with their hand,
and squeeze their hand to release the tool holder (thereby applying a Newtonian reaction
force on the front end of the tool holder with the palm of his hand). This may cause
the tool holder to unlock the tool shank held therein during removal of the tool holder,
so that, when the tool holder is replaced on the spindle, the tool is ejected out
of the tool holder as soon as the hammer is actuated. Alternatively, it is possible
for the tool holder to be inserted incorrectly so that the tool holder is ejected
when the hammer is actuated. In the case of the arrangement described in US-A-5,437,465
on the other hand, in which a ring must be moved axially rearwardly in order to remove
the tool holder from the spindle, removal of the tool holder necessitates the operator
using both his hands for the purpose.
[0006] According to a first aspect of the present invention there is provided a hammering
and/or drilling tool which includes a hollow spindle and a tool holder that can be
attached to an end of the spindle and removed therefrom, the tool holder comprising:
a tool holder body which can be fitted within the end of the spindle and releaseably
locked therein by means of at least one locking element; and
a locking ring for releasably holding the or each locking element in a locked position
in which the locking element(s) lock(s) the tool holder to the spindle,
characterised in that the tool holder comprises a manually actuable sleeve for rotating the locking ring
in a first direction and for rotating the tool holder body in a second opposite direction,
and resilient means for urging the tool holder body to follow the movement of the
locking ring in the first direction and the locking ring to follow the movement of
the tool holder body in the second direction, said resilient means urging the locking
ring and the tool holder body into relative rotational positions in which the locking
ring holds the or each locking element in the locked position.
[0007] This tool holder locking and release arrangement reliably fixes the tool holder to
the spindle and enables quick and easy removal of the tool holder from the spindle
and quick and easy replacement of the or an alternative tool holder to the spindle.
Also, it is relatively easy to find the correct starting rotational positioning of
the tool holder on the spindle in the same manual operation as rotating the manually
actuable sleeve to fix the tool holder onto the spindle.
[0008] In one embodiment the locking ring may be rotated by the sleeve in a first, preferably
clockwise, direction to release the tool holder from the spindle and the tool holder
body may be rotated by the sleeve in the second opposite, preferably anti-clockwise,
direction to lock the tool holder to the spindle. The locking elements may be mounted
at the end of the spindle so as to be radially shiftable. The manually actuable sleeve
may rotate the tool holder body via a member non-rotatably mounted on the tool holder
body.
[0009] The manually actuable sleeve may be mounted for limited rotation with respect to
the locking ring and the tool holder body. In particular the manually actuable sleeve
may be mounted for limited rotation in the first direction with respect to the tool
holder body and/or may be mounted for limited rotation in the second direction with
respect to the locking ring.
[0010] The resilient means may be a coil spring with a first end fixed to the locking ring
and a second end fixed to the member.
[0011] In one embodiment of the first aspect of the present invention the tool holder portion
may have a recess for each locking element and the locking ring may have a recess
for receiving each locking element, which locking ring recess has a deep portion and
a shallow portion, arranged such that when the deep portion is in register with a
locking element the locking element can move out of the tool holder recess and the
tool holder can be removed from or fitted to the spindle and when a shallow portion
is in register with a locking element the locking element is locked in the corresponding
tool holder recess and the tool holder is fixed to the spindle. Each tool holder recesses
may be formed in a radially outwardly facing surface of the tool holder and each locking
ring recess may be formed in a radially inwardly facing surface of the locking ring.
[0012] The first aspect of the present invention also provides a tool holder that can be
attached to an end of a spindle of a drilling and/or hammering tool and removed therefrom,
the tool holder comprising:
a tool holder body which can be fitted to the end of the spindle and releaseably locked
thereto by means of at least one locking element; and
a locking ring for releasably holding the or each locking element in a locked position
in which the locking element(s) lock(s) the tool holder to the spindle,
characterised in that the tool holder comprises a manually actuable sleeve for rotating the locking ring
in a first direction and rotating the tool holder body in a second opposite direction,
and resilient means for urging the tool holder body to follow the movement of the
locking ring in the first direction and the locking ring to follow the movement of
the tool holder body in the second direction, said resilient means urging the locking
ring and the tool holder body into relative rotational positions in which the locking
ring holds the or each locking element in the locked position.
[0013] The tool holder according to the first aspect of the present invention may have the
subsidiary features discussed above in relation to the hammering and/or drilling tool
according to the first aspect of the present invention.
[0014] A second aspect of the drilling and/or hammering tool according to the present invention
is characterised in that the locking ring has an internal radius that varies along
its circumference so that rotation of the locking ring about the axis of the tool
holder body will move it between a locking position in which it causes the or each
locking element to retain the tool holder body in the spindle, and a release position
in which it will allow the or each locking element to move radially to release the
tool holder body.
[0015] Thus, since locking of the tool holder involves rotation of the locking ring, it
is relatively easy to find the correct angular orientation of the tool holder about
the spindle in the same manual operation. In addition, it is relatively easy to arrange
for movement of the various parts of the tool holder for unlocking the tool from the
tool holder and for releasing the tool holder from the spindle to occur in orthogonal
directions so that the two operations will not interfere with each other.
[0016] The or each locking element will normally be located in an aperture in one of the
spindle or the tool holder body, and will engage a depression in the other of the
spindle or the tool holder body to retain the tool holder body in the spindle, so
that the tool holder body can be retained in the spindle only when the tool holder
body is in a defined orientation with respect to the axis of the spindle. In most
cases, the or each locking element will be located in an aperture in the spindle,
and will engage a depression in the tool holder body (inserted therein) when it is
in its radially innermost position to retain the tool holder on the spindle.
[0017] The tool holder may include a manually operable sleeve that is associated with the
locking ring in order to enable a user to rotate the locking ring between the locking
position and the release position. The locking ring may have, in this case, a region
of relatively large internal radius forming a pocket that can receive a locking element
when the element is in its radially outermost position (to allow release of the tool
holder body), and a region of relatively small internal radius that can receive the
locking element only when the locking element is in a radially inner position in which
it engages its depression. In this arrangement, the locking ring may be biased (usually
spring biased) with respect to the tool holder body into its locking position. Thus,
for instance, whether or not the tool holder is located on the spindle, the locking
ring may be biased so that the region(s) of the locking ring of relatively small radius
is in circumferential register with the depression(s) in the tool holder body that
receive the locking element(s).
[0018] The second aspect of the present invention also provides a tool holder that can be
attached to an end of a spindle of a drilling and/or hammering tool and removed therefrom,
the tool holder having a tool holder body that can be inserted into the end of the
spindle and retained therein by means of at least one locking element that is movable
in a radial direction to retain, or to allow release of, the tool holder body, and
a locking ring for holding the or each locking element in a position that retains
the tool holder body in the spindle, characterised in that the locking ring has an
internal radius that varies along its circumference so that rotation of the locking
ring about the axis of the tool holder body will move it between a locking position
in which it causes the or each locking element to retain the tool holder body in the
spindle, and a release position in which it will allow the or each locking element
to move radially to release the tool holder body.
[0019] The tool holder according to the second aspect of the present invention may have
the subsidiary features discussed above in relation to the hammering and/or drilling
tool according to the second aspect of the present invention.
[0020] As discussed above, in relation to both aspects of the present invention the manually
operable sleeve may be rotatable with respect to the locking ring to a limited extent,
and also with respect to the tool holder body to a limited extent. Thus, the locking
ring can be held in its locking position in this case (or more accurately, the locking
ring and the tool holder body are held with respect to one another so that the locking
ring is in its locking position) against the spring bias by means of the manually
operable sleeve, which can be provided with some form of detent to limit further rotation.
Rotation of the manually operable sleeve in one sense (either clockwise or anticlockwise)
may be arranged to cause corresponding rotation of the tool holder body but can allow
the locking ring to remain stationary (with respect to the spindle), while rotation
of the manually operable sleeve in the opposite sense may be arranged to require corresponding
rotation of the locking ring but can allow the tool holder body to remain stationary.
In this arrangement, the tool holder body can be inserted in the end of the spindle
so that the or each locking element is in its radially outermost position and is received
in a pocket of the locking ring, and manual rotation of the sleeve in one sense will
cause the tool holder body to rotate with respect to the spindle but the locking ring
will be prevented from rotating with respect to the spindle by means of the or each
locking element until the or each depression is in circumferential register with a
locking element, whereupon the or each locking element will move radially inwardly
into its depression and allow the locking ring to rotate under the bias into its locking
position. This rotation of the locking ring will normally be accompanied by a clear
audible click that will signal to the operator that the tool holder is correctly engaged
with the spindle in its locked state. In order to remove the tool holder from the
spindle, the sleeve may be manually rotated about the spindle in the opposite sense
which will cause the locking ring to rotate together with the sleeve against the spring
bias until the or each locking element is in register with a pocket of the locking
ring, whereupon the or each locking element will move radially outwardly into its
pocket to allow removal of the tool holder.
[0021] Although the tool holder may, in principle, be arranged so that it can be released
from the spindle by rotation of the locking ring and/or the sleeve in either the clockwise
or anti-clockwise direction, it is preferred for the tool holder to be released from
the spindle if the locking ring and/or the sleeve is rotated in the clockwise direction
(viewed forwardly along the axis of the tool holder body) only. This is because rotary
hammers are designed for the tool, and therefore the tool holder, to rotate in a clockwise
direction. Therefore, if the sleeve accidentally brushes against a wall or other stationary
object during operation, the wall or other object will exert a torque on the sleeve
in the anti-clockwise direction (with respect to the rest of the tool holder) and
so maintain the tool holder locked in the hammer spindle.
[0022] One form of hammer and tool holder in accordance with the present invention will
now be described by way of example, with reference to the accompanying drawings, in
which:
Figure 1 is a sectional elevation along the common axis of the spindle and tool holder
of a hammer and tool holder according to the invention;
Figure 2 is an exploded perspective view of the tool holder and part of the spindle
shown in Figure 1;
Figure 3 is a sectional elevation along the common axis of the spindle and modified
tool holder according to the invention; and
Figure 4 is a perspective view of the manually operated sleeve of the modified tool
holder of figure 4.
[0023] Referring to the accompanying drawings, a hammer that may be employed in a combination
rotary hammer mode, includes a spindle 1 that is provided with an air-cushion hammer
mechanism comprising a piston 2, that is caused to reciprocate within the spindle
by a swash or wobble mechanism 4 driven by a motor (not shown). Reciprocating motion
of the piston causes a ram 6 to reciprocate, which strikes a beatpiece 8. The beatpiece
8 strikes the shank of a drill or chisel bit (not shown) that is held in the bore
of a tool holder 10 in known manner.
[0024] The hammer includes a removable tool holder 10 for holding the shank of a bit, for
example a hammer drill bit or a chipping bit. The tool holder 10 as shown is designed
to hold a bit that has a pair of closed-end elongate recesses for receiving a locking
element for retaining the bit in the tool holder while allowing some degree of axial
movement, and a pair of open-ended grooves for receiving rotary driving splines 12,
such bits being of a design referred to as "SDS Plus", but tool holders for other
designs such as SDS Max, hex shank etc. may also be employed. The tool holder includes
a hollow, generally cylindrical tool holder body 14 that has a rearward end 16 that
can be inserted into the forward end 18 of the hammer spindle 1. A locking ball 20
for retaining the bit in the tool holder 10 is located in an elongate aperture 22
in the tool holder body 14, and is held in a position in which it extends into the
bore of the tool holder body 14 (and into the recess of any bit held therein) by means
of locking ring 24. The locking ring 24 is located in an axially slidable release
sleeve 26 which can be moved rearwardly against the bias of a spring 28 to allow the
locking ball 20 to move radially outwardly into recess 30 in order to allow removal
of the bit.
[0025] The tool holder body 14 is held in the spindle 1 by means of four locking balls 32
located in apertures 34 in the spindle wall. The apertures 34 are slightly tapered
in order to prevent the balls falling into the bore of the spindle 1, and the balls
are held in the apertures by means of a snap ring 36. The locking balls 32 can move
to a limited extent in the radial direction between a radially outermost position
which allows attachment and removal of the tool holder 10, and a radially innermost
position in which the tool holder is retained on the spindle. The tool holder body
14 has four depressions 38 in its outer surface for receiving the locking balls 32
when the tool holder 10 is retained on the spindle.
[0026] The tool holder 10 is provided with a manually operable sleeve 40 that can be rotated
about the tool holder body 14 to a limited extent, and which houses a locking ring
42 that is positioned about the locking balls 32, and is held in the sleeve 40 by
a radially compressed snap ring 43. The sleeve 40 also houses an annular plate 44
(shown partially cut-away in figure 2 to show its flanged periphery 45). The locking
ring 42 has four peripheral projections 46 that can abut internal shoulders 48 in
the sleeve 40 formed by portions 50 of greater wall thickness in order to limit the
extent to which the locking ring can rotate with respect to the sleeve. In a similar
fashion, the annular plate 44 has a pair of projections 52 in its periphery that can
abut further internal shoulders 54 in the sleeve 40 to limit the extent to which the
annular plate can rotate with respect to the sleeve. The annular plate 44 has a central
aperture 56 to enable it to be located about the tool holder body 14, the aperture
56 having a flat 58 that cooperates with a flattened region 60 of the tool holder
body 14 in order to prevent rotation of the annular plate 44 about the tool holder
body. The annular plate 44 and the locking ring 42 are connected to each other by
means of a helical spring 62, one end of which is located in a hole 64 in the annular
plate, and the other end of which rests against one of the projections 46 on the locking
ring. The spring 62 biases the annular plate 44 and the locking ring 42 to the limit
of their rotation within the sleeve 40, that is to say, so that the projections 46
and 52 thereon abut the internal shoulders 48 and 54 in the sleeve, and so that the
locking ring 42 and the tool holder body 14 can only be rotated with respect to the
sleeve against the bias of the spring 62.
[0027] The locking ring 42 has an irregular inner surface having four relatively thick (i.e.
of relatively small internal radius) regions 66 separated by four recesses 68. The
recesses 68 themselves each have one portion 70 that is relatively deep and an adjacent
portion 72 that is relatively shallow. The portions 70 of the recesses that are relatively
deep provide pockets that can receive the locking balls 32 even when they are in their
radially outermost position for allowing attachment and removal of the tool holder
10, but the relatively shallow portions 72 of the recesses 68 can receive the locking
balls 32 only when they are in their radially innermost position. The relatively thick
regions 66 cannot receive the locking balls 32 whatever position they are in.
[0028] The sleeve 40, annular plate 44, locking ring 42 and tool holder body 14 are arranged
so that the spring 62 biases the locking ring to a position in which the relatively
shallow portions 72 of the recesses 68 are in circumferential register with the depressions
38 in the tool holder body, and so that the locking ring can be rotated by a maximum
of about 45° until the pockets 70 are in register with the depressions 38.
[0029] In order to install the tool holder 10 on the spindle 1 of the hammer, it is simply
pushed onto the end 18 of the spindle so that the end 16 of the tool holder body 14
is located within the bore of the spindle. The end of the tool holder body will force
the locking balls 32 radially outwardly to their outermost position. Further pushing
of the tool holder 10 onto the spindle will result in the locking ring 42 abutting
the locking balls 32. The tool holder 10 can then be rotated until the locking balls
32 are in register with the pockets 70 in the locking ring, whereupon the tool holder
may be pushed further into the spindle until the rearwardly disposed face of the annular
plate 44 abuts the end of the spindle, and the locking balls 32 are received in the
pockets 70. This is the intermediate position which is referred to below. The sleeve
40 is then rotated in an anticlockwise direction by about 45° which causes rotation
of the tool holder body 14 via the annular plate 44. Because the locking balls 32
are in their radially outermost position, they cannot be received in the relatively
shallow portions 72 of the recesses 68, and the locking ring remains stationary with
respect to the spindle, and so rotates, with respect to the sleeve 40 in a clockwise
direction against the bias of the spring 62. The rotation of the sleeve (40) causes
rotation of the tool holder body (14) via the annular plate (44). As soon as the tool
holder 10 has been rotated about the spindle by about 45°, the depressions 38 in the
tool holder body 14 will become in register with the locking balls 32 and the locking
balls will move radially inwardly into their locking position in which they are received
in the depressions 38. This radial movement of the locking balls 32 enables them to
be received by the relatively shallow portions 72 of the recesses 68 in the locking
ring 42, whereupon the locking ring will rotate in the anticlockwise direction under
the bias of the spring 62 into its locking position with a clearly audible snap. The
tool holder 10 is then firmly fixed on the end of the spindle.
[0030] In this operation, it is not necessary for the operator to align the tool holder
with any parts of the spindle. The tool holder is simply pushed into the spindle,
rotated until the locking balls 32 are received within the pockets 70 (observed a
further axial movement of the tool holder 10) and the ring 40 rotated further until
the locking ring 42 snaps into its locking position.
[0031] In order to remove the tool holder 10 from the spindle 1, the sleeve 40 is simply
rotated by about 45° in the clockwise direction. This movement forces the locking
ring 42 to rotate with the sleeve 40, but tool holder body 14 and the annular plate
44 remain stationary, due to the locking balls 32 engaging the depressions 38. Thus,
with respect to the sleeve 40 and locking ring 42, the tool holder body and annular
plate rotate in an anticlockwise direction against the bias of the spring 62. When
the locking ring 42 has rotated so that the locking balls 32 are in register with
the pockets 70, the locking balls 32 will immediately move radially outwardly into
the pockets. The tool holder body 14 is now free to move and will rotate in the clockwise
direction under the bias of the spring 62 until the protuberances 52 once again abut
the internal shoulders 54 in the sleeve 40, and the depressions 38 are out of register
with the locking bodies 32 and the recesses (38) in the tool holder body are out of
register with the locking balls (32). This rotation also occurs with a clearly audible
snap. The tool holder may then simply be pulled axially off the spindle 1.
[0032] A modified form of tool holder is shown in figures 3 and 4. This form of tool holder
is essentially the same as that shown in figures 1 and 2, but instead of a snap ring
43, the locking ring 42 is held within the interior of the sleeve 40 by means of a
retention ring 100 having a generally "L" shaped circumferential cross-section. The
retention ring 100 is provided with four flap portions 102 which fit inside the interior
of the sleeve 40, and are each provided with a small protuberance 104, as shown in
the shape of a double-headed arrow, that will fit inside a corresponding hole 106
in the wall of the sleeve to provide a positive engagement of the retention ring 100
in the sleeve 40.
1. A drilling and/or hammering tool which includes a hollow spindle (1) and a tool holder
(10) that can be attached to an end (18) of the spindle and removed therefrom, the
tool holder having a tool holder body (14) that can be inserted into the end of the
spindle and retained therein by means of at least one locking element (32) that is
movable in a radial direction to retain, or to allow release of, the tool holder body,
and a locking ring (42) for holding the or each locking element in a position that
retains the tool holder body in the spindle, characterised in that the locking ring has an internal radius that varies along its circumference so that
rotation of the locking ring about the axis of the tool holder body will move it between
a locking position in which it causes the or each locking element to retain the tool
holder body in the spindle, and a release position in which it will allow the or each
locking element to move radially to release the tool holder body.
2. A tool as claimed in claim 1, wherein the or each locking element (32) is located
in an aperture (34) in one of the spindle or the tool holder body, and will engage
a depression (38) in the other of the spindle or the tool holder body to retain the
tool holder body (14) in the spindle, so that the tool holder body can be retained
in the spindle only when the tool holder body is in a defined orientation with respect
to the axis of the spindle.
3. A tool as claimed in claim 2, wherein the or each locking element (32) is located
in an aperture (34) in the spindle, and will engage a depression (38) in the tool
holder body when it is in its radially innermost position to retain the tool holder
on the spindle.
4. A tool as claimed in claim 2 or 3, wherein the tool holder includes a manually operable
sleeve (40) that is associated with the locking ring (42) to enable a user to rotate
the locking ring between the locking position and the release position, the locking
ring having a region of relatively large internal radius forming a pocket (70) that
can receive a locking element when the element is in its radially outermost position
(to allow release of the tool holder body), and a region (72) of relatively small
internal radius that can receive the locking element only when the locking element
is in a radially inner position in which it engages its depression (38).
5. A tool as claimed in any one of claims 1 to 4, wherein the locking ring (42) is biased
with respect to the tool holder body into its locking position.
6. A tool as claimed in any one of claims 4 or 5, wherein the manually operable sleeve
(40) is rotatable with respect to the locking ring to a limited extent.
7. A tool as claimed in claim 6, wherein the manually operable sleeve (40) is rotatable
with respect to the tool holder body to a limited extent, and the locking ring is
held in its locking position against the bias by means of the manually operable sleeve.
8. A tool as claimed in claim 7, wherein the tool holder body (14) can be inserted in
the end of the spindle so that the or each locking element (32) is in its radially
outermost position and is received in a pocket (70) of the locking ring, and manual
rotation of the sleeve (40) in one sense will cause the tool holder body (14) to rotate
with respect to the spindle but the locking ring (42) will be prevented from rotating
with respect to the spindle by means of the or each locking element until the or each
depression (38) is in circumferential register with a locking element, whereupon the
or each locking element will move radially inwardly into its depression and allow
the locking ring to rotate under the bias into its locking position.
9. A tool as claimed in claim 8, wherein, when the tool holder (10) is inserted in the
end of the spindle and the locking ring (42) is in its locking position, manual rotation
of the sleeve (40) about the spindle in the opposite sense will cause the locking
ring to rotate together with the sleeve against the bias until the or each locking
element is in register with a pocket (70) of the locking ring, whereupon the or each
locking element will move radially outwardly into its pocket to allow removal of the
tool holder.
10. A tool as claimed in any one of claims 1 to 9, wherein the tool holder includes an
arrangement for holding a tool therein, the tool holder including a part (26) that
is moved manually in an axial direction to release the tool.
11. A tool holder (10) that can be attached to an end of a spindle (1) of a drilling and/or
hammering tool and removed therefrom, the tool holder having a tool holder body (14)
that can be inserted into the end of the spindle and retained therein by means of
at least one locking element (32) that is movable in a radial direction to retain,
or to allow release of, the tool holder body, and a locking ring (42) for holding
the or each locking element in a position that retains the tool holder body in the
spindle, characterised in that the locking ring (42) has an internal radius that varies along its circumference
so that rotation of the locking ring about the axis of the tool holder body will move
it between a locking position in which it causes the or each locking element to retain
the tool holder body in the spindle, and a release position in which it will allow
the or each locking element to move radially to release the tool holder body.
12. A tool holder for a drilling and/or hammering tool comprising a manually actuable
sleeve (40) wherein components of the tool holder are held within the sleeve by a
snap ring (100) which snap ring is fitted within the sleeve, characterised in that the snap ring has at least one resilient arm (102) and the sleeve has a corresponding
number of through holes (105) which extend to a radially outwardly facing surface
of the sleeve, arranged such that the or each arm is engageable with a corresponding
through hole in a snap fit, and each arm and through hole cooperate so that the portion
(104) of the or each arm which can be viewed from the radially outwardly facing surface
of the sleeve appears in the shape of a symbol.
13. A tool holder according to claim 12 wherein at least the radially outermost part of
the or each through hole (105) is formed in the shape of the symbol.
14. A tool holder according to claim 13 wherein the radially outermost portion of the
or each arm (104) is formed in the shape if the symbol to fit the corresponding through
hole.
15. A tool holder according to claim 12 wherein the radially outermost portion (104) of
the or each arm extending through the corresponding through hole is in the shape of
the symbol.
16. A tool holder according to any one of claims 12 to 15 wherein the or each resilient
arm (102) is formed with a latch element (104) in the shape of the symbol and the
latch element is received in a snap fit within a correspondingly shaped through hole
(105).
17. A tool holder according to any one of claims 12 to 16 wherein the symbol is an arrow
designating the direction in which the manually actuable sleeve can be moved.
18. A tool holder according to any one of claims 12 to 17 wherein the manually actuable
sleeve is actuable to fit and/or remove a tool or bit from the tool holder.
19. A tool holder according to any one of claims 12 to 17 wherein the manually actuable
sleeve is actuable to fit and/or remove the tool holder form the drilling and/or hammering
tool.