The invention relates to a drill of the kind that is hand-held and
comprises a casing, a driving spindle rotatably journaled in the casing for, during
operation, rotating a driven spindle which is in an operatable position in which
it is coaxially flush with the driving spindle, a driving motor for directly or
indirectly rotating the driving spindle, a coupling for connecting and disconnecting
the engagement of the driven spindle with the driving spindle, a turret head revolvably
mounted on the casing and provided with at least two driven spindles and arranged
in such a way that the spindles one by one can be rotated into operatable position,
a first coupling part of the coupling made on the end of the driven spindle that
faces the driving spindle, an opposite second coupling part connected to the driving
spindle in a nonrotatable manner and axially movable between a connected and disconnected
position in relation to this driving spindle, and means for manually moving the
second coupling part between its connected and disconnected position.
Generally, hand-held drills have chucks for clamping a rotary tool.
In many cases, such a drill is employed for jobs that require consecutive use of
various tools which therefore one by one are clamped in the chuck.
An example of such a job is a job that simply consists in screwing
a wood screw into a piece of wood. When a conventional drill with one spindle is
employed for this purpose, the following operations are required.
A drill bit is clamped in the chuck while the drill is inoperative.
A hole is predrilled in the wood by actuating the drill. The drill is dwelled. The
chuck is opened. The drill bit is removed. A screw bit is clamped in the chuck instead
and the screw is screwed into the predrilled hole by reactuating the drill.
If the job only comprises a single or a small number of screws, it
is still manageable to employ a drill with only one operatable spindle despite the
many operations. However, this is not the case if the job comprises many screws.
Then, the many tool changes will really be an inconvenience to the operator just
as they will take up a considerable part of the total time spent on doing the job.
The problem has been tried solved by providing a hand-held drill with
several driven spindles which one at the time are coupled into operative engagement
with the driving spindle of the drill. Each of the driven spindles then has a chuck
with a tool that is not changed as long as the same kind of work is done repeatedly.
Thereby, the many tool changes are saved.
Such a drill is known from US 5,573,358. In this case, there are two
driven spindles both journaled in a revolvable arrangement of bearings which can
bring either one of the driven spindles into operative engagement with the drive
shaft of the drill upon turning. During such a turning manoeuvre, the driven spindles
will travel in a large curve. Thereby, the structure with the projecting spindles
and their chucks will become unstable in itself. The revolvable arrangement of bearings
is therefore supported by a guideway. But as the spindle with the tool which is
not in use at the moment is hanging out to the side, the drill becomes lopsided
and unhandy and also difficult to operate in narrow spaces, e.g. in a corner. On
changes between the two driven spindles, the revolvable arrangement of bearings
is turned back and forth in relation to the rest of the drill. This known structure
is relatively complex and unwieldy, and it is difficult to employ and has a limited
The object of the invention is to provide a drill of the kind mentioned
in the opening paragraph, that has a simple, stably functioning design and that
is easy and safe to operate.
The novel and unique features according to the invention, whereby
this is achieved, is the fact that the drill furthermore comprises a guideway extending
parallel to the axis of the driving spindle, a slide movably received in the guideway
and having a through channel extending coaxially to the driving spindle, whereby
the second coupling part is extending rotatably through the channel of the slide
and is retained in this channel against axial movement.
Having this design, a driven spindle can now be coupled into and out
of engagement with the driving spindle easily and quickly quite simply by operating
the coupling instead of conventionally having to move the turret head with its chucks
and tools in relation to the rest of the drill.
The driven spindle, which currently is in the operatable position
on the drill, is coupled into and out of the engagement with the driving spindle
by axially moving the second coupling part back and forth during which the second
coupling part is effectively supported and guided.
In a constructively simple variant of this embodiment, the second
coupling part can merely consist of a coupling bar which is extending into an axially
extending end hole in the driving spindle in an axially movable but nonrotatable
manner and is extending through the channel of the slide in a rotatable manner but
secured against axial displacement.
Alternatively, the second coupling part can consist of a bushing journaled
in the channel of the slide in a rotatable manner but secured against axial displacement,
and a coupling bar extending into or through the bushing in a nonrotatable manner
secured against axial displacement and into an axially extending end hole in the
driving spindle in a nonrotatable and movable manner.
In the casing, a coupling spring or a similar means for affecting
the slide with a force acting in direction towards the driven spindle can be located
to automatic couple the second coupling part to the first coupling part so that
the respective driven spindle can be employed to perform an operation with a rotary
tool clamped in e.g. a chuck on the spindle.
When a second driven spindle subsequently is to be turned into operatable
position on the drill, the second coupling part first has to be disconnected from
its engagement with the first coupling part. Advantageously, this disconnection
can take place by means of finger knobs mounted on the slide or the second coupling
part and extending out through the casing.
A driven spindle with a rotary tool used for a specific operation
is disconnected in a simple manner by pushing the finger knobs. Then, the spindle
with the next rotary tool to be used is turned into operatable position on the drill
after which the finger knobs are released. Thereby, the second coupling part is
forced into engagement with the first coupling part of the new spindle by means
of the spring power of the coupling spring whereby the new spindle is automatically
coupled together with the driving spindle. Now, the associated rotary tool is immediately
ready for being operatively used.
However, it is important that the turret head is locked securely in
the new angular position in relation to the casing of the drill when the new rotary
tool is used.
For this purpose, the drill can be provided with a lock which advantageously
can consist of at least one on the slide and a corresponding recess in the turret
head for each driven spindle or a catch in the turret head for each driven spindle
and a corresponding recess in the slide.
When the coupling spring automatically couples the second coupling
part to the first part, the above lock will now simultaneously lock the turret head
and the drill together. Then, the wanted rotary operation can be performed safely
and effectively and without any risk of the operator getting hurt because of the
turret head unintentionally beginning to rotate.
In many cases a hand-held drill has a base for placing the drill on
when it is not in use. However, the weight of the turret head and its associate
components will move the centre of gravity of the entire drill forward so that the
drill is likely to overturn when it is placed on a supporting face.
In an advantageous embodiment the base or a lower part of this base
can be disposed movably in relation to the rest of the drill. When the base or base
part is moved forward, the centre of gravity of the drill will be within the surface
of support of the base. When the drill is to be used, the base or base part is pulled
back to a position which is convenient to the operator.
The invention will be explained in greater detail below, describing
only exemplary embodiments with reference to the drawing, in which
- Fig. 1 is a side elevational view of a drill according to the invention with
a turret head and a disconnected driven spindle with a screw bit, partly in axial
- Fig. 2 is a view of the drill in fig. 1 but with an connected second driven
spindle with a drill bit,
- Fig. 3 is on a larger scale a fractional view of a coupling for the drill in
figs. 1 and 2 in disconnected state,
- Fig. 4 is a view of the coupling in fig. 3 but in connected state,
- Fig. 5 is a fractional, perspective view of the turret head in figs. 1 and 2
in locked state,
- Fig. 6 is a view of the turret head in fig. 5 but in unlocked state and during
turning of the turret head,
- Fig. 7 is a second embodiment of the drill according to the invention provided
with a movable base in a position of use, and
- Fig. 8 is the embodiment in fig. 7 but with the base in a position of rest.
Figs. 1 and 2 show a drill 1 according to the invention with a turret
head 2. The drill has a casing 3 with a handle 4. A trigger 5 is found in the handle
for actuating the drill. A driving motor 6 is also found in the casing for via a
gearing 7 rotating a driving spindle 8 which is rotatably journaled in the casing.
By means of a bearing 9, the turret head 2 is revolvably mounted on
an oblique face 10 made on the front end of the casing and forming and angle of
preferably 45° - 65° with the axis of the driving spindle.
In the case shown, the turret head is provided with two driven spindles
11 and 12 mutually forming an angle which is twice as large, that is an angle of
between 90° and 130°. Thereby, the tool which at a given moment is inactive will
advantageously be extending in approximately the same direction as the handle so
that it will not be in the way for operating the drill or happen to hit the handle
when the turret heat is attempted turned.
A chuck 13 with a clamped screw bit 14 is mounted on the spindle 11,
and a chuck 15 with a clamped drill bit 16 is mounted on the spindle 12.
The drill comprises a coupling 17 for connecting and disconnecting
the driven spindle which at a given moment is in operatable position in which its
axis is extending in continuation of the axis of the drive shaft.
The coupling 17, which is seen best in fig. 3 and fig. 4, has a first
coupling part 18;19 on the end of the driven spindle 11 and 12 respectively, and
an opposite second coupling part 20 which is connected to the driving spindle 8
in a nonrotatable but axially movable manner.
The coupling can be designed in any expedient manner, for example
as a claw coupling (not shown).
In this case, the second coupling part 20 consists of a coupling bar
21 extending in an axially movable but nonrotatable manner into an axially extending
end hole 22 in the driving spindle 8, and a bushing 23. The coupling bar is furthermore
extending in a nonrotatable manner and secured against axial movement into or through
the centre aperture of the bushing. In the case shown, the coupling bar and the
end hole of the driving spindle and the centre aperture of the bushing respectively
are hexagonal, but said securing against rotation can be established in any other
expedient manner within the scope of the invention, for example as a key and slot
coupling (not shown).
Connection takes place by pushing the second coupling part 20 forward
and disconnection takes place by pulling the second coupling part 20 back. The coupling
17 is in a connected state in figs. 2 and 4 and a disconnected state in figs. 1
A guideway 24 is furthermore mounted in the casing and is extending
parallel to the axis of the drive shaft. A slide 25 is movably mounted in the guideway.
The slide has a through channel 26 and the bushing 24 is extending through this
channel in a rotatable but axially immovable manner. A coupling spring 27 serves
for automatically moving the slide 25 and thereby the second coupling part 20 axially
and coupling the coupling part 20 together with the first coupling part 18.
A check pawl 28 is made on the slide and is received in a longitudinal
slit 29 in the guideway 24 in a slidably movable manner. A corresponding locking
notch 30 is made in the turret head. These details are seen best in fractions in
figs. 5 and 6 which also show that the slide is provided with finger knobs 31 extending
out through the casing.
When the operator has to change from e.g. the screw bit 14 in figs.
1 and 3 to the drill bit 16 in figs. 2 and 4, he manually pulls the finger knobs
31 and thereby the slide 25 back in the direction indicated by the arrow. As the
second coupling part 20 of the coupling 17 is axially secured by the bushing 23
which again is axially secured by the slide 25, the second coupling part is disconnected
from its engagement with the first coupling part 18. At the same time the pawl 28
is pulled out of its locking engagement with the locking notch 30 in the turret
In fig. 6, both the coupling and the lock have been disconnected.
Thereby, the turret head is allowed to be turned in the direction indicated by the
arrow so that the drill bit 16 (not shown in figs. 5 and 6) now can be brought into
operatable position in which the corresponding driven spindle 12 is coaxially flushing
with the driving spindle.
When the operator then releases the finger knobs 31, the coupling
spring 27 will push the slide 25 forward in direction towards the first coupling
part 18. Thereby, the driving spindle 8 and the driven spindle 12 are coupled together,
and the turret head 2 is simultaneously locked in the casing 3 of the drill.
As can be seen, the drill according to the invention has a simple,
safe and stably functioning structure which is easy to operate. As the turret head
is automatically locked to the casing of the drill when the driven spindle is coupled
to the driving spindle, the operator can operate the drill without any risk during
this of getting hurt because of the turret head beginning to rotate during an operation.
Figs. 7 and 8 show a second embodiment of the drill 32 according to
the invention. This embodiment corresponds to the one described above and shown
in figs. 1-6, and will therefore not be described in detail once more.
In this case however, the drill 32 has a base 33 for placing the drill
on when the operator puts the drill down on a supporting face.
The base is constructed of a guideway 34 on the handle 4 and a slide
34 movably received in the guideway.
In fig. 7, the slide is in a retracted position of use in which the
slide does not inconvenience the operator.
In fig. 8, the slide is in an advanced position in which its surface
of support 36, at least partly, is vertically beneath the total centre of gravity
of the drill and the turret head. In this position the drill can safely be placed
on a supporting face 37.
In a preferred embodiment said movable base comprises a rechargeable
battery (not shown) for supplying the necessary power to the driving motor. Contacts
(not shown) can be arranged in the base for connecting the battery to the motor
when the drill is being used and disconnecting this connection when the base is
pushed forward and the drill is placed on a supporting face.
The invention is described above and shown in the drawing on the assumption
that the turret head is provided with two driven spindles having chucks with a screw
bit and a drill bit respectively.
Naturally, this is only to be taken as an example as the turret head
within the scope of the invention can have several driven spindles each operating
with any kind of rotary tool, of which screw bits, drill bits, cutters, broaches,
circular saws, and grinders can be mentioned.