Machine tools abstract
A chuck system for machine tools with a rotating jaw chuck has
clamping jaws of the jaw chuck which can be radially adjusted relative
to an axis of rotation. The clamping jaws are displaceably mounted
in a bearer connected with a drive shaft, and in which engagement
openings for the introduction of an adjustment tool for the positioning
of the clamping jaws are arranged in the region of the bearer. The
bearer is surrounded by a protective sheath that is guided so as
to be displaceable in the direction of the axis of rotation. The
protective sheath comprises through openings, which are arranged
so as to be congruent to the engagement openings in a handling position
of the protective sheath, and are arranged so as to be offset to
the engagement openings in an operating position of the protective
sheath. In the operating position, the clamping jaws are radially
surrounded, at least in regions, by the protective sheath. In the
handling position, the protective sheath brings an operating switch
into a switched-off position.
Machine tools claims
We claim as our invention:
1. A chuck system for an engraving cylinder in an electronic engraver,
comprising:
a rotating jaw chuck for engagement with an electronic engraver
engraving cylinder, clamping jaws of the jaw chuck being radially
adjustable relative to an axis of rotation;
the clamping jaws being displaceably mounted in a bearer that is
connected with an engraving cylinder drive shaft;
engagement openings arranged in a region of the bearer for introduction
of an adjustment tool for positioning of the clamping jaws;
the bearer being surrounded by a protective sheath that is displaceably
guided in a direction of the axis of rotation;
the protective sheath comprising through openings which in a handling
position of the protective sheath are arranged congruent to the
engagement openings and in an operating position of the protective
sheath are arranged so as to be offset to the engagement openings;
the protective sheath at least partially radially surrounding a
leading end of the clamping jaws when the sheath is in the operating
position and being withdrawn from the leading end of the clamping
jaws in the handling position; and
in said handling position, the protective sheath actuating an operating
switch into a switched-off position.
2. A chuck system according to claim 1 wherein the operating switch
comprises an actuating element that is pressed into a base member
of the operating switch in the switched-off position of the operating
switch.
3. A chuck system according to claim 1 wherein three engagement
openings are arranged along a circumference of the protective sheath
and which are offset by 120.degree. to one another.
4. A chuck system according to claim 1 wherein the operating switch
is actuated by a rearward edge of the protective sheath.
5. A chuck system according to claim 1 wherein for determination
of the operating position of the protective sheath, a stop that
limits mobility of the protective sheath relative to the bearer
is provided.
6. A chuck system according to claim 1 wherein for determination
of the handling position of the protective sheath, a stop that limits
mobility of the protective sheath relative to the bearer is provided.
7. A chuck system according to claim 1 wherein a stop element for
predetermination of a least adjustment force of the sheath is arranged
in a region of contact of the bearer and the protective sheath.
8. A chuck system according to claim 1 wherein a guide element
for prevention of rotational movements of the protective sheath
relative to the bearer is arranged in a region of boundary surfaces
facing one another of the bearer and the protective sheath.
9. A chuck system for machine tools, comprising:
a rotating jaw chuck, clamping jaws of the jaw chuck being radially
adjustable relative to an axis of rotation;
the clamping jaws being displaceably mounted in a bearer that is
connected with a drive shaft;
engagement openings arranged in a region of the bearer for introduction
of an adjustment tool for positioning of the clamping jaws;
the bearer being surrounded by a protective sheath that is displaceably
guided in a direction of the axis of rotation;
the protective sheath comprising through openings which in a handling
position of the protective sheath are arranged congruent to the
engagement openings and in an operating position of the protective
sheath are arranged so as to be offset to the engagement opening;
the protective sheath at least partially radially surrounding the
clamping jaws;
two pairs of through openings are respectively arranged along a
circumference of the protective sheath so as to be offset by 120.degree.;
and
in each pair of through openings, one of the through openings corresponds
respectively with an engagement opening for radial positioning of
the clamping jaws, and an additional through opening corresponds
with an engagement opening for rotationally symmetrical arrangement
of the jaw chuck relative to the axis of rotation.
10. A chuck system for an engraving cylinder in an electronic engraver,
comprising:
an electronic engraver having an engraving cylinder;
a rotating jaw chuck for engagement with said engraving cylinder,
clamping jaws of the jaw chuck being radially adjustable relative
to an axis of rotation;
the clamping jaws being displaceably mounted in a bearer;
at least one engagement opening arranged in a region of the bearer
for introduction of an adjustment tool for positioning of the clamping
jaws;
the bearer being surrounded by a protective sheath that is displaceably
guided in a direction of the axis of rotation;
the protective sheath comprising at least one through opening which
in a handling position of the protective sheath is arranged congruent
to the engagement opening with the sheath withdrawn from a region
of a leading end of the clamping jaws, and in an operating position
of the protective sheath is arranged so as to be offset to the engagement
opening with the sheath radially surrounding a region of a leading
end of the clamping jaws; and
the protective sheath activating a cut-off switch in said handling
position which prevents operating rotation of the jaw chuck.
Machine tools description
BACKGROUND OF THE INVENTION
The invention concerns a chuck element for machine tools with a
rotating jaw chuck, in which clamping jaws of the jaw chuck are
radially adjustable relative to an axis of rotation, and in which
the clamping jaws are mounted displaceably in a bearer connected
with a drive shaft, and in which engagement openings are arranged
in the region of the bearer for the introduction of an adjusting
element for the positioning of the clamping jaws.
Machine tools of this sort are used in a plurality of embodiments.
For example, different embodiments are lathes or milling machines.
Another embodiment is that of an engraving machine for printing
cylinders for rotogravure. Before the beginning of the engraving,
the print cylinder is clamped into the engraving machine. The clamping
in of the print cylinder occurs in such a way that axis pieces of
the print cylinder are held in adjustable jaw chucks. Normally,
three clamping jaws are thereby used. This clamping ensures a secure
seating of the print cylinder during engraving. Chuck devices of
this sort are also used for fastening scanning cylinders.
However, the known machine tools comprise certain operating characteristics
that do not guarantee all requirements for an optimal working safety.
For the adjustment of the clamping jaws, it is necessary to introduce
a suitable tool into the rotatably mounted part of the machine tool.
If the machine tool is unintentionally switched on during the introduction
of the tool or of the print cylinder, operator injury can result.
Another problem is that with clamping jaws that protrude externally,
sharp edges are exposed, which can cause injury if immediate contact
with the hand of an operator takes place. This is likewise critical
above all for rotating machine parts.
SUMMARY OF THE INVENTION
It is an object of the present invention to construct a machine
tool of the type named above in such a way that operating safety
is increased.
According to the invention, a chuck system is provided for machine
tools. The chuck system has a rotating jaw chuck and clamping jaws
of the jaw chuck which are radially adjustable relative to an axis
of rotation. The clamping jaws are displaceably mounted in a bearer
that is connected with a drive shaft. Engagement openings are arranged
in a region of the bearer for introduction of an adjustment tool
for positioning of the clamping jaws. The bearer is surrounded by
a protective sheath that is displaceably guided in a direction of
rotation. The protective sheath has two openings which in a handling
position of the protective sheath are arranged congruent to the
engagement openings and in an operating position of the protective
sheath are arranged so as to be offset to the engagement openings.
The protective sheath at least partially radially surrounds the
clamping jaws
The invention is explained in more detail on the basis of FIGS.
1 to 4.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-section through a bearer provided with a jaw
chuck, the bearer being surrounded by a protective sheath;
FIG. 2 is a highly schematized top view of a bearer with jaw chuck,
with a positioning of the clamping jaws that is altered in relation
to FIG. 1;
FIG. 3 shows a cross-section according to the sectional line III--III
in FIG. 2; and
FIG. 4 is a partial representation of a region of the circumference
of the protective sheath.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a cross-section through a bearer 1 that can be coupled
with a drive shaft (not shown) of a drive motor via a connecting
element 2. The bearer 1 thereby extends along an axis of rotation
3. In general, the drive shaft of the drive motor is oriented in
the direction of the axis of rotation. However, it is also possible
in principle to implement a different arrangement of the drive motor
via a corresponding deflection gearing.
The bearer 1 comprises a jaw chuck 4 on its side facing away from
the connecting element 2 which jaw chuck is formed of clamping
jaws 5 arranged displaceably along jaw guides 6. A displacement
of the clamping jaws 5 can occur only by means of an adjustment
tool 7 which can be introduced into engagement openings 8 of the
bearer 1. A positioning of the clamping jaws 5 relative to the bearer
1 can occur via a suitable coupling, e.g. via interlocked elements
or spindle-shaped elements with riders. Upon removal of the adjustment
tool 7 an unintentional adjustment of the clamping jaws 5 is avoided
by means of suitable catches.
The bearer 1 is surrounded by a protective sheath 9 that can be
displaced relative to the bearer 1 in the direction of the axis
of rotation 3. In an operating position 10 of the protective sheath
9 shown in the upper part of FIG. 1 a front edge 11 of the protective
sheath 9 is arranged so that an upper edge 12 of the clamping jaws
5 is somewhat covered. This ensures that in the operating position
10 the clamping jaws 5 do not protrude from the protective sheath
9 in a direction facing away from the connecting element 2 or at
least do so only insignificantly. The protective sheath 9 likewise
covers the jaw chuck 4 transverse to the axis of rotation 3.
In the operating position 10 region of the protective sheath 9
are arranged so as to be offset relative to the entry openings 8
of the bearer 1. In this way, it is not possible to introduce the
adjustment tool 7 into the engagement openings.
An operating switch 14 assumes its switched-on setting in the operating
position 10 of the protective sheath 9. The switched-on setting
is preferably constructively designed in such a way that an actuating
element 15 of the operating switch 14 protrudes from a base member
16 of the operating switch 14. This prevents malfunctioning of the
operating switch 14 for example given a wedging of the actuating
element 15. A wedging is possible with the selected design construction
only in the switched-off setting of the operating switch 14; in
this way, risks to the operating personnel are avoided.
For the positioning of the actuating element 15 the protective
sheath 9 comprises a leading edge 17 arranged along its circumference.
The leading edge 17 is formed as a beveling which presses in when
the protective sheath 9 is retracted from the operating position
10 into a handling position 18 shown in the lower half of FIG. 1
and thus guides the operating switch 14 over into its switched-off
setting.
In the handling position 18 of the protective sheath 9 the engagement
opening 8 and the through opening 13 are arranged congruently with
one another, so that the adjustment tool 7 can be introduced into
the engagement opening 8 by which means the clamping jaws 5 are
positioned. It is for example possible, using the clamping jaws
5 to brace a workpiece to be processed with the bearer 1.
To avoid unintentional displacements of the protective sheath 9
relative to the bearer 1 a stop element 19 is arranged in the region
of the boundaries of the bearer 1 facing one another and the protective
sheath 9. The stop element 19 can be designed as a threaded bolt
that engages in a corresponding recess 20. For example, according
to FIG. 1 the stop element 19 can be arranged in the region of the
bearer 1 and the recess 20 can be provided in the region of the
protective sheath 9. However, it is likewise possible to select
a complementary embodiment. In a displacement of the protective
sheath 9 a force must first be overcome that retracts the stop
element. A displacement of the protective sheath 9 is possible only
after overcoming this force.
It is likewise useful to provide a limiting of the positioning
path of the protective sheath 9 relative to the bearer 1. A possible
realization of such a limiting of the positioning path is shown
in FIG. 1. Here a pin 21 is set in a boring of the protective sheath
9 which pin protrudes inwardly from the protective sheath 9 in
the direction towards the axis of rotation 3. The pin 21 thereby
engages in a longitudinal groove 22 of the bearer 1 that extends
essentially parallel to the axis of rotation 3. The longitudinal
groove 22 direction towards the engagement opening 8 by a shoulder
23. When the pin 21 comes into contact with the shoulder 23 the
protective sheath 9 is located in the operating position 10. A limiting
element 24 is provided for the determination of the handling position
18. The limiting element 24 can be arranged on the bearer 1 and
can extend, in regions, into the longitudinal groove 22. When the
limiting element 24 contacts the pin 21 the protective sheath 9
assumes the handling position 18. In the embodiment shown in FIG.
1 the limiting element 24 is designed as a screw that is screwed
into a boring of the bearer 1 and protrudes into the longitudinal
groove 22 with a screw head.
The use of the protective sheath of the invention in connection
with the operating switch comprises the following advantages. By
means of the arrangement of the protective sheath in the region
of the bearer, it is ensured that in the operating position the
clamping jaws are laterally covered, and thus a risk of injury is
avoided. In addition, in the operating position of the protective
sheath it is not possible to introduce a tool for adjusting the
jaw chuck into the bearer. Due to the arrangement of the through
openings and of the engagement openings, an introduction of the
tool is possible only given a retracted positioning of the protective
sheath. However, in this retracted positioning the operating switch
is switched off, so that an unintentional switching on of the machine
tool is prevented. It is thus securely excluded that the machine
tool can switch on when a tool is in use, and that the unprotected
ends of the clamping jaws can rotate.
FIG. 2 schematically illustrates that the clamping jaws 5 can be
positioned inside the jaw guides 6 and that their ends protrude
from the bearer 1 in the radial direction. The protective sheath
9 surrounds the jaw chuck 4 in the radial direction, and thus avoids
contact of operating personnel with the clamping jaws 5 in the operating
position 10 of the protective sheath 9.
FIG. 3 again illustrates schematically that an external contact
with the clamping jaws 5 is not possible transversely to the axis
of rotation 3.
FIG. 4 shows that, for a circumferential region of the protective
sheath 9 through openings 13 can be respectively arranged pair
by pair in the region of the protective sheath 9. This corresponds
with a corresponding pair-by-pair arrangement of engagement openings
8. One of the engagement openings 8 is provided for the positioning
of the clamping jaws 5 and the other engagement opening 8 is provided
for the radial displacement of the entire jaw chuck 4 in order
to implement a rotationally symmetrical arrangement in relation
to the axis of rotation 3. In order to support a simple handling,
three pairs of through openings 13 are respectively arranged along
the circumference of the protective sheath 9 offset by 120.degree.
to one another. In the region of the bearer 1 three pairs of entry
openings 8 are correspondingly provided.
By means of the radial surrounding of the clamping jaws 5 by the
protective sheath 9 in the operating position 10 it is also ensured
that an impermissibly wide arrangement of the clamping jaws 5 cannot
be implemented. It is compulsory that the clamping jaws 5 here always
be arranged so far inside the jaw guides 6 that a sufficient fastening
of the clamping jaws 5 and thereby a safe operation, is ensured.
It is thus not possible to exceed a maximal chuck region, which
is to be maintained in a manner conditioned by the construction.
A standard chuck key can be used as an adjustment tool 7 for the
positioning of the clamping jaws 5 relative to the jaw guide 6.
To ensure the true running of the jaw chuck 4 wedge rod adjustments
can be used.
Although various minor changes and modifications might be proposed
by those skilled in the art, it will be understood that my wish
is to include within the claims of the patent warranted hereon all
such changes and modifications as reasonably come within my contribution
to the art.
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