Machine tools abstract
A releasable coupling for motorized machine tools including first
and second coupling elements which are uncoupled when a predetermined
triggering torque occurs. The first coupling element includes first
locking elements, such as balls, while the second coupling element
includes corresponding second locking elements, such as recesses.
The first coupling element includes a concentric holding element.
The holding element is rotatable with respect to the first and second
coupling element between an inactive position and an active position.
In the inactive position, the holding element allows the first and
second locking elements to engage one another to maintain the first
and second coupling elements in a coupled arrangement. After the
predetermined triggering torque has occurred and the holding element
is rotated into the active position, the holding element prevents
the first and second locking elements from engaging one another
to maintain the first and second coupling elements in a uncoupled
arrangement. When the first and second locking elements are disengaged
and the holding element is in the active position, the first and
second locking elements are rotatable with respect to one another
into, and away from, a coupling rotary position. When the holding
element is in the active position, the holding element prevents
an elastic force from acting on the first and second locking elements
when they are in the coupling rotary position, thereby preventing
the first and second locking elements from engaging one another.
Machine tools claims
What is claimed is:
1. A coupling for motorized machine tools, comprising:
a driven side and a drive side which are releasable from one another;
a first coupling element which is non-rotatably connected to one
of said driven side and said drive side, said first coupling element
being rotatable about an axis of rotation, and having at least one
first locking element associated therewith;
a second coupling element which is non-rotatably is connected to
another one of said driven side and said drive side, said second
coupling element being rotatable about said axis of rotation and
having at least one second locking element associated therewith;
said first and second locking elements being moveable relative
to each other from a coupled position to an uncoupled position when
a predetermined triggering torque occurs;
a holding element coaxial with said first coupling element, said
first coupling element and said holding element cooperating via
a protrusion arranged on one of said first coupling element and
said holding element, and two movement limiting surfaces, having
a spacing in an azimuthal direction, being arranged on another one
of said first coupling element and said holding element, said spacing
of said movement limiting surfaces allowing rotational movement
of said holding element with respect to said first coupling element
to only a limited extent, said rotational movement enabling said
holding element to transition between an inactive position and an
active position;
an elastic force storing means; wherein:
in said coupled position, said elastic force storing means acts
on at least one of said first and second locking elements to maintain
said first and second locking elements in said coupled position,
thereby causing said first and second coupling elements to rotate
in concert;
when said predetermined triggering torque occurs, said first and
second locking elements are moved relative to each other into said
uncoupled position and said holding element is moved with respect
to said first and second coupling elements from said inactive position
to said active position;
in said uncoupled position, said first and second locking elements
are rotatable relative to each other into a coupling rotary position
and away from said coupling rotary position, and when said first
and second locking elements are in said coupling rotary position:
(a) said first and second locking elements enter into said coupled
position when said holding element is in said inactive position
because said holding element allows said elastic force storing means
to act on said at least one of said first and second locking elements;
and
(b) said first and second locking elements maintain said uncoupled
position when said holding element is in said active position because
said holding element prevents said elastic force storing means from
acting on said at least one of said first and second locking elements.
2. A coupling as defined in claim 1 wherein, once said predetermined
triggering torque has occurred and said holding element is in said
active position, the holding element prevents a transition of the
first and second locking elements from the uncoupled position into
the coupled position when the coupling rotary position has been
reached for as long as the coupling is being driven on the drive
side.
3. A coupling as defined in claim 1 wherein:
the holding element is adapted to be brought from the inactive
position into the active position by relative rotational movement
between the first and second coupling elements.
4. A coupling as defined in claim 1 wherein:
the holding element is adapted to be brought from the inactive
position into the active position by rotational movement of the
holding element relative to at least one of the first and second
coupling elements.
5. A coupling as defined in claim 4 wherein:
the holding element is adapted to be brought from the inactive
position into the active position by rotational movement of the
holding element relative to both of the first and second coupling
elements.
6. A coupling as defined in claim 1 wherein:
the holding element, in the active position, prevents the elastic
force storing means from acting on said at least one of said first
and second locking elements to allow said first and second locking
elements to maintain the uncoupled position when the first and second
locking elements are in said coupling rotary position.
7. A coupling as defined in claim 1 wherein:
the holding element is supported, in the active position, on said
second coupling element.
8. A coupling as defined in claim 7 wherein:
the holding element is unlimitedly rotatable about the axis of
rotation relative to the second coupling element while said holding
element is in the active position.
9. A coupling as defined in claim 8 wherein:
when the holding element is in the active position, the holding
element and the first coupling element are unlimitedly rotatable
relative to the second coupling element.
10. A coupling as defined in claim 9 wherein:
the holding element is limitedly rotatable in relation to the first
coupling element from the inactive position to the active position.
11. A coupling as defined in claim 7 wherein:
when the holding element is in the active position, the holding
element and the first coupling element are positionable with respect
to one another between an active rotary position and an inactive
rotary position; and
when the holding element is in the inactive rotary position and
the holding element and the second coupling element are positioned
with respect to one another in an initial rotary position, the holding
element is adapted to be transferred from the active position to
the inactive position.
12. A coupling as defined in claim 11 wherein:
when the first and second locking elements are in the coupled position,
the holding element is located in the initial rotary position, and,
at the same time, the first and second locking elements are located
in the coupled position such that the elastic force storing means
holds the first and second locking elements in the coupled position.
13. A coupling as defined in claim 11 wherein
when the holding element and said first coupling element are positioned
in said active rotary position with respect to each other:
(a) either the first and second locking elements are positioned
away from the coupling rotary position and remain in the uncoupled
position when the holding element is located in the initial rotary
position; or
(b) the first and second locking elements are located in the coupling
rotary position when the holding element is located away from the
initial rotary position.
14. A coupling as defined in claim 11 wherein:
the first and second coupling elements are designed such that the
first and second locking elements, when rotated away from the coupling
rotary position, maintain said first and second coupling elements
uncoupled from one another.
15. A coupling as defined in claim 11 wherein:
the holding element and the second coupling element are designed
such that when the holding element is in the active position, the
holding element is held in the active position in all rotary positions
of the holding element relative to the second coupling element which
are away from the initial rotary position, thereby preventing any
transition of the first and second locking elements from the uncoupled
position to the coupled position.
16. A coupling as defined in claim 11 wherein:
interacting adjusting elements are provided for moving the holding
element from the inactive position to the active position.
17. A coupling as defined in claim 16 wherein:
at least one of the adjusting elements has an inclined surface,
and at least one other of the adjusting elements is movable relative
to said inclined surface in an adjusting direction.
18. A coupling as defined in claim 16 wherein:
the adjusting elements displace the holding element in an adjusting
direction during rotational movement of said holding element relative
to said second coupling element.
19. A coupling as defined in claim 16 wherein:
said interacting adjusting elements are arranged in pairs with
each pair being operative between the holding element and the second
coupling element.
20. A coupling as defined in claim 19 wherein:
each one of said interacting adjusting elements has an identical
design and is arranged in an axially symmetrical pattern in relation
to the axis of rotation.
21. A coupling as defined in claim 11 wherein:
at least one interacting pair of adjusting elements is provided
for moving the holding element from the inactive position to the
active position;
at least one pair of said first and second locking elements is
provided said second locking element of said at least one pair of
said first and second locking elements is arranged on the second
coupling element according to a first pattern;
one of said adjusting elements of said at least one pair of adjusting
elements is arranged on the second coupling element according to
a second pattern, said first and second patterns on said second
coupling element being arranged with a defined relative position
with respect to each other;
said first locking element of said at least one pair of said first
and second locking elements is arranged on the first coupling element
according to said first pattern;
another one of said adjusting elements of said at least one pair
of adjusting elements is arranged on said holding element in said
second pattern;
when the holding element is in the inactive position, said another
one of said at least one pair of adjusting elements is arranged
in said defined relative position with respect to said first locking
element; and
when the holding element is in the active position, one of said
at least one pair of adjusting elements said another is rotated
with respect to said first locking element.
22. A coupling as defined in claim 1 wherein:
said first and second locking elements comprise a plurality of
locking elements operative between the first and second coupling
elements.
23. A coupling as defined in claim 22 wherein:
each one of said plurality of locking elements being identically
designed and arranged in axial symmetry in relation to said axis
of rotation.
24. A coupling as defined in claim 23 wherein:
a plurality of adjusting elements are operative between the holding
element and the second coupling element; wherein
the plurality of adjusting elements are arranged in said axial
symmetry in relation to said axis of rotation.
25. A coupling as defined in claim 11 wherein:
when the holding element is in an initial rotary position, the
at least one of said first and second locking elements is adapted
to be transferred from the uncoupled position to the coupled position
by the elastic force storing means acting on said at least one of
said first and second locking elements.
26. A coupling as defined in claim 11 wherein:
the holding element is adapted to be transferred from the inactive
position to the active position only when the first and second locking
elements are in the uncoupled position.
27. A coupling as defined in claim 26 wherein:
the holding element is movable from the inactive position into
the active position when the first and second locking elements are
in the uncoupled position.
28. A coupling as defined in claim 27 wherein:
the first and second locking elements, in the uncoupled position,
prevent the elastic force storing means from acting on the holding
element during movement of the holding element from the inactive
position into the active position.
Machine tools description
BACKGROUND OF THE INVENTION
The invention relates to a coupling, in particular for machine
tools driven by a motor, which is releasable when a predetermined
triggering torque occurs, comprising a coupling element rotatable
about an axis of rotation and having at least one first locking
element, and an additional coupling element rotatable about the
axis of rotation and having at least one second locking element,
wherein in a coupled position the locking elements are aligned in
a defined coupling rotary position relative to one another and in
relation to the axis of rotation and are in an operative position
engaging in one another and wherein in an uncoupled position the
locking elements are disengaged in an inoperative position, and
an elastic force storing means which acts on the locking elements
in the coupled position in the sense of maintaining the coupled
position.
Couplings of this type are known for machine tools driven by a
motor. These serve primarily as safety couplings in order to prevent
any further operation when the tool is blocked and thus any breaking
of the tool or any release of the machine tool from its attachment.
Couplings of this type are preferably used in machine tools for
driving drilling tools, in particular drill bits.
The known couplings are predominantly claw couplings, with which
the locking elements designed as claws disengage at the occurrence
of the countertorque in their momentary coupling rotary position
but always engage again in additional, possible coupling rotary
positions and must then be caused to disengage again by means of
the triggering torque so that such known couplings "chatter".
As a result, not only does a torque corresponding to the triggering
torque occur at the first disconnection of the coupling but always
subsequent to this additional torques of the order of magnitude
of the triggering torque which act on the drive side of the coupling
and, therefore, result in an increased wear and tear and/or increased
attachment requirements not only with regard to the coupling but
also on the drive side.
The object underlying the invention is therefore to improve a coupling
of the generic type such that this no longer "chatters".
SUMMARY OF THE INVENTION
This object is accomplished in accordance with the invention, in
a coupling of the type described at the outset, in that the coupling
has a holding element, that the holding element is movable from
an inactive position into an active position once the triggering
torque has occurred, that the holding element in the active position
prevents any transition of the locking elements from the inoperative
position into the operative position in every coupling rotary position,
this transition being triggered by the action of the elastic force
storing means, and that the holding element in the inactive position
allows a transition of the locking elements from the inoperative
position into the operative position in every coupling rotary position,
this transition being triggered by the elastic force storing means.
A coupling rotary position within the meaning of the inventive
solution is to be understood, in particular, as all the rotary positions
of the coupling elements relative to one another, in which the locking
elements have the possibility of engaging in one another and of
passing automatically into the coupled position as a result of their
shape, e.g. with the action of the elastic force storing means.
The advantage of the inventive solution is to be seen in the fact
that once the triggering torque has been reached once the holding
element in its active position prevents any transition of the locking
elements from the inoperative position into the operative position
and therefore the "chattering" of the coupling no longer
occurs and, consequently, the triggering torque also occurs only
once and then need no longer be used up so that not only the coupling
but also the machine tool and the tool are subject to less wear
and tear.
With the inventive solution, the locking elements, in particular,
are to be arranged on the respective associated coupling elements
such that these follow the rotational movement of the respective
coupling element in all positions thereof. This means that the locking
elements are, for example, either rigidly connected to the respective
coupling element or the respective coupling element forms a receiving
means or a cage so that the locking element is taken along by the
coupling element during a rotation about the axis of rotation.
So that the inventive coupling acts as a safety coupling, it is
particularly advantageous that once the triggering torque has occurred
the holding element prevents a transition of the locking elements
from the inoperative position into the operative position when the
respective coupling rotary position is reached for as long as the
coupling is being driven on the drive side. This ensures that the
coupling remains in the uncoupled position until the drive is switched
off and the undesired high triggering torques cannot occur a number
of times.
With respect to the manner, in which the holding element is transferred
from the inactive into the active position, the most varied of possibilities
are conceivable. A particularly advantageous possibility provides
for the holding element to be brought from the inactive into the
active position by means of a relative rotational movement between
the coupling elements in the uncoupled position. The advantage of
this solution is to be seen in the fact that this utilizes the relative
movement between the coupling elements which occurs in any case
in order to transfer the holding element from the inactive into
the active position.
It would, for example, be possible in this respect to merely convey
a linear movement to the holding element. A solution is, however,
particularly expedient, in which the holding element can be brought
from the inactive into the active position by means of a rotational
movement relative to at least one of the coupling elements.
The transfer of the holding element from the inactive position
into the active position can be realized, however, in a particularly
simple and reliable manner when the holding element can be brought
from the inactive position into the active position by means of
a relative rotational movement in relation to both coupling elements.
With respect to the action of the holding element for preventing
the transition of locking member and locking member receiving means
from the inoperative into the operative position in the coupling
rotary position, the most varied possibilities are conceivable.
One advantageous solution, for example, provides for the holding
element to block any movement of the locking elements from the inoperative
position into the operative position, i.e., either acts on the respective
locking element or the coupling element comprising this locking
element. This solution has the advantage that it ensures that the
locking elements remain in their inoperative position.
Another alternative provides for the holding element to prohibit
any action of the elastic force storing means on the locking elements
in the sense of any movement thereof from the inoperative position
into the operative position so that the locking elements do have
the possibility of engaging but not under the influence of the elastic
force storing means, and thus--should this be the case--can be disengaged
again immediately without any large torque. The advantage of this
solution is to be seen in the fact that no direct action on the
locking elements is required but only an action on the elastic force
storing means or the transfer elements arranged between this and
the coupling or locking elements is required and this is simple
to accomplish from a constructional point of view.
The holding element could, in principle, be operative in the most
varied of ways. It would, for example, be conceivable for the holding
element to be supported on a housing of the coupling. It is, however,
particularly advantageous for the holding element to be supported
in the active position on one of the coupling elements, for example
a second coupling element. This solution has the great advantage
that the holding element can be designed such that it interacts
directly with the second coupling element in its active position
and so the inventive coupling can be built particularly small from
a constructional point of view.
The holding element is preferably supported on a side of the second
coupling element directly facing it.
In this respect, it is particularly expedient when the holding
element is unlimitedly rotatable about the axis of rotation relative
to the second coupling element supporting it in the active position.
This offers the possibility of having the holding element rotate
in relation to the second coupling element when the coupling is
in a released position.
Particularly expedient is an embodiment, in which the holding element
in the active position is unlimitedly rotatable relative to the
second coupling element together with a first coupling element so
that the holding element can be rotated unlimitedly together with
the first coupling element in the uncoupled position.
In this respect, it is particularly expedient when the holding
element is limitedly rotatable in relation to the first of the coupling
elements from a defined inactive rotary position into a defined
active rotary position so that both rotary positions can easily
be determined in a defined manner.
In order to preferably ensure that the holding element in its inactive
rotary position relative to the first coupling element has the possibility
of passing into its inactive position, the holding element and the
second coupling element are designed such that in at least one defined
initial rotary position of the two relative to one another the holding
element can be transferred into the inactive position.
The initial rotary position of the holding element is to be understood
as all the rotary positions of the holding element relative to the
second coupling element, in which the holding element has the possibility,
e.g. under the influence of the elastic force storing means, of
passing into the inactive position.
Such an inventive coupling is preferably designed such that in
the coupled position the holding element is located in the initial
rotary position relative to the second coupling element and at the
same time the locking elements are located in the coupling rotary
position relative to one another and in this position the force
storing means holds the locking elements in the operative position.
This embodiment is expediently designed, in addition, such that
when the holding element is located in an active rotary position
relative to the first coupling element either the locking elements
are located outside their coupling rotary position and remain in
their inoperative position when the holding element is located in
an initial rotary position relative to the second coupling element
or when the locking elements are located in a coupling rotary position
the holding element is located outside the initial position and
in its active position in relation to the second coupling element.
With this embodiment, the first coupling element and the second
coupling element rotate relative to one another about the axis of
rotation in the uncoupled position and the holding element rotates
with the first coupling element, whereby, one time, the holding
element reaches the initial rotary position during this rotational
movement and another time the locking elements reach the coupling
rotary positions but the initial rotary position and the coupling
rotary position are never reached at the same time and so the uncoupled
position is maintained.
In order to constantly maintain the inoperative position of the
locking elements in the uncoupled position in an embodiment of the
inventive coupling designed in this manner, a preferred alternative
provides for the coupling elements to be designed such that these
are held in their inoperative position outside the coupling rotary
position of the locking elements. This means that it is merely necessary
for the holding element to reach its active position when the coupling
rotary position is reached and in this position prevent the locking
elements from passing into their operative position.
In a second solution alternative to the preceding solution or supplementing
it, it is provided for the holding element and the second coupling
element to be designed such that these hold the holding element
in its active position in all the positions outside the initial
rotary position and thus prevent any transition of the locking elements
from the inoperative into the operative position. This means that
it is necessary only when the initial rotary position of the holding
element relative to the second coupling element is reached for the
coupling elements to be designed such that in this initial rotary
position the locking elements do not pass from their inoperative
into their operative position.
It is, however, also possible to amalgamate both alternatives to
form a combined solution.
No details have been given in conjunction with the preceding description
of the individual embodiments concerning the movement of the holding
element from the inactive into the active position. For example,
one advantageous embodiment provides for interacting adjusting elements
to be provided for moving the holding element from the inactive
into the active position.
The adjusting elements can be designed in the most varied of ways.
It is preferably provided for at least one of the adjusting elements
to have an inclined surface, the other adjusting element being movable
in relation to this surface, wherein the inclined surface extends
transversely to an adjusting direction of the adjusting device.
An adjusting cam and an adjusting cam outer support are preferably
provided as adjusting elements, with one of the two expediently
being arranged on the holding element and the other on the second
coupling element.
In order to utilize the adjusting elements, in particular, in the
embodiment, in which a transition from the active position into
the inactive position takes place due to a rotational movement of
the holding element, it is preferably provided for the adjusting
elements to displace the holding element in the adjusting direction
during a rotational movement of the holding element.
In a particularly advantageous embodiment, one of the locking elements
is arranged on the second coupling element in a first pattern and
one of the adjusting elements in a second pattern which is aligned
in a defined relative position in relation to the first pattern,
the other locking element is arranged on the first coupling element
in the first pattern and the other one of the adjusting elements
on the holding element in the second pattern, in the inactive rotary
position of the holding element the second pattern of the holding
element is located in the defined relative rotary position in relation
to the first pattern of the first coupling element, as in the case
of the second coupling element, and in the active rotary position
of the holding element the second pattern of the holding element
is rotated out of the defined relative rotary position in relation
to the first pattern of the first coupling element.
Particularly favorable solutions, in particular in order to achieve
symmetrical loads on the coupling elements, provide for several
pairs of locking elements to be operative between the coupling elements.
These pairs are preferably of an identical design and arranged in
axial symmetry in relation to an axis of rotation of the coupling
elements so that the possibility is thereby provided, in addition,
of reaching a coupling rotary position during less than one revolution
of the coupling elements relative to one another.
Furthermore, an additional, advantageous embodiment provides for
several pairs of adjusting elements to be operative between the
holding element and the second coupling element in order to likewise
achieve a load thereon which is as even as possible.
The pairs of adjusting elements are also preferably of an identical
design and arranged in an axially symmetrical pattern in relation
to the axis of rotation, the axial symmetry expediently being the
same as in the case of the locking elements so that the possibility
is given of attaining a coupled position of the coupling with the
holding element in an inactive rotary position and less than one
revolution of the holding element relative to the second coupling
element.
A particularly compact construction of the inventive coupling is
possible when the coupling elements are arranged opposite one another.
This solution can be made even more compact when the second coupling
element and the holding element are likewise located opposite one
another.
With respect to the possibilities of transferring the holding element
from the inactive into the active position, no details have been
given in conjunction with the preceding explanations of the individual
embodiments. It would, in principle, be conceivable to have the
holding element constantly acted upon by an elastic force storing
means which--when possible--transfers this from the active position
into the inactive position.
It is, however, particularly advantageous from a constructional
point of view when, in the initial rotary position, the holding
element can be transferred into the inactive position by the elastic
force storing means acting on the locking elements.
This solution may be advantageously developed further from a constructional
point of view in that the holding element can be transferred from
its inactive position into the active position only when the locking
elements are in their inoperative position so that the holding element
need make no contribution to the locking elements reaching the inoperative
position.
In addition, this solution can be advantageously developed further
in that the holding element is freely movable from the inactive
position into the active position when the locking elements are
in the inoperative position so that no appreciable torque is required
to attain the active position of the holding element.
This can be accomplished particularly favorably when the locking
elements in the inoperative position prevent the elastic force storing
means from acting on the holding element during the transition of
the holding element from the inactive into the active position.
With respect to the design of the locking elements themselves,
no details have been given in conjunction with the preceding description
of the individual embodiments of the inventive coupling.
In an embodiment with a particularly simple design, for example,
one of the locking elements is designed as a locking cam, this cam
being rigidly connected with the corresponding coupling element.
Such a cam can be integrally formed on a coupling element particularly
easily, with the cam in the simplest case being formed on the coupling
element in one piece.
In a solution, which is even more advantageous but more complicated,
one of the locking elements is designed as a rolling body so that
in the position, in which the locking element has to counteract
the force of the elastic force storing means, the rolling body can
roll along a corresponding countersurface and--in contrast to a
rigid locking cam--no sliding friction occurs between the coupling
elements but rolling friction and, thus, essentially no countertorque
acts in the uncoupled position.
Such a rolling body could be designed in the simplest case such
that it is mounted in the coupling element associated with it, for
example in a corresponding recess partially surrounding the rolling
body.
In the embodiment specified above, the elastic force storing means
would preferably act on the coupling element mounting the rolling
body, for example a corresponding contact surface thereof.
It is, however, even more advantageous when the rolling bodies
penetrate the respective coupling element and on their side located
opposite the other coupling element are acted upon directly by the
elastic force storing means so that the elastic force storing means
does not act on the coupling element itself but merely directly
on the rolling bodies.
In order, in addition, to create the possibility of the rolling
bodies being able to roll along the respectively other coupling
element, it is preferably provided for the elastic force storing
means to act on the rolling bodies by means of a pressure disk rotatable
about the axis of rotation, this pressure disk preferably being
mounted for rotation by an axial bearing. This solution has the
great advantage that the rolling bodies can roll, on the one hand,
along the respectively other coupling element and, on the other
hand, along the pressure disk and thus a type of roller bearing
results between the other coupling element and the pressure disk.
The elastic force storing means preferably comprises a stack of
elastic force storing means, the pressure disk and an axial bearing
operative between the two.
No details have so far been given with respect to the design of
the other adjusting elements respectively interacting with the locking
cams or rolling bodies as one of the adjusting elements. In one
advantageous embodiment, for example, the other adjusting element
has two wall surfaces, which extend transversely to the direction
of rotation and between which the locking cam or the rolling body
engages in its operative position.
These wall surfaces are, for example, the wall surfaces of recesses
or also, for example, grooves, the grooves preferably being arranged
to extend in radial direction in relation to the axis of rotation.
It is particularly expedient, in particular in order to be able
to determine a defined triggering torque which is easily reproducible,
when the wall surfaces of the other locking element form together
with the locking cam or the rolling body at least one inclined surface
which extends at an angle to the direction of rotation and due to
the inclination of which the triggering torque can be defined.
No more detailed explanations have so far been given concerning
the type of design of the adjusting elements. It is particularly
advantageous when the adjusting elements are designed in the same
manner as the locking elements so that a simple and inexpensive
manufacture of the inventive coupling is already possible for reasons
of functional efficiency.
In principle, the adjusting elements and the locking elements can
be arranged in different patterns relative to the axis of rotation.
It is, however, particularly expedient when the adjusting elements
and the locking elements are arranged on the same circular path
and are of an identical design so that the inventive coupling is
particularly simple to produce due to the identity of adjusting
and locking elements and, moreover, the one locking elements can
also be brought into engagement with the respectively other adjusting
elements and vice versa. This allows the coupling to be returned
from the uncoupled position to the coupled position in a particularly
simple manner since the one adjusting elements can engage with the
other adjusting elements or locking elements which are closest in
return direction and also the one locking elements can engage with
the locking elements or adjusting elements closest in return direction.
Additional features and advantages of the invention are the subject
matter of the following description as well as the drawings of several
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a longitudinal section through a first embodiment
of an inventive coupling;
FIG. 2 shows a section along line 2--2 in FIG. 1 with locking
elements located in a coupling rotary position and an operative
position and a holding element located in an initial rotary position
relative to a second one of the coupling elements and in an inactive
rotary position relative to a first one of the coupling elements;
FIG. 3 shows a section in linear development along line 3--3 in
FIG. 2 with locking elements located in a coupling rotary position
and an operative position and the holding element located in an
initial rotary position relative to the second one of the coupling
elements and in an inactive rotary position relative to the first
one of the coupling elements;
FIG. 4 shows a section along line 4--4 in FIG. 1;
FIG. 5 shows a section similar to FIG. 3 immediately after transition
of the locking elements from an operative into an inoperative position
and thus transition into the uncoupled position as well as a holding
element still in an initial rotary position relative to the second
coupling element;
FIG. 6 shows a section similar to FIG. 2 with a holding element
in an active rotary position;
FIG. 7 shows a section similar to FIG. 3 with a holding element
in an active rotary position relative to the first coupling element
and a holding element in an initial rotary position relative to
the second coupling element;
FIG. 8 shows a section similar to FIG. 3 with a holding element
in an active rotary position and locking elements in a coupling
rotary position;
FIG. 9 shows a longitudinal section through a second embodiment
of an inventive coupling in a machine tool;
FIG. 10 shows a longitudinal section similar to FIG. 9 through
a third embodiment of an inventive coupling in a machine tool;
FIG. 11 shows a section corresponding to FIG. 3 through the third
embodiment;
FIG. 12 shows a section along line 12--12 in FIG. 10 with a holding
element in an inactive rotary position relative to the first coupling
element corresponding to FIG. 2;
FIG. 13 shows a section similar to FIG. 11 immediately after a
transition of the coupling into the uncoupled position and a holding
element still in an initial rotary position corresponding to FIG.
5;
FIG. 14 shows a section similar to FIG. 12 with a holding element
in an active rotary position corresponding to FIG. 6;
FIG. 15 shows a section similar to FIG. 11 with a holding element
in an active rotary position relative to the first coupling element
and a holding element in an initial rotary position relative to
the second coupling element corresponding to FIG. 7 and
FIG. 16 shows a section similar to FIG. 11 with a holding element
in an active rotary position relative to the first coupling element
and locking elements located in a coupling rotary position relative
to one another, corresponding to FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of an inventive coupling, designated as a whole
as 10 and illustrated in FIG. 1 comprises a stub shaft 16 which
is driven at a first end 12 for example, by means of a toothed
wheel 14 and which has at a region located opposite the first end
a guide attachment 18 with an outer cylindrical surface 22 cylindrical
to an axis of rotation 20 of the stub shaft 16.
The outer cylindrical surface 22 is provided in a section 24 12
with a flat surface 26 which faces a first end 12 and with which
a first coupling element designated as a whole as 30 can be driven.
The first coupling element 30 comprises, as illustrated in FIGS.
1 and 2 a first ring 32 which is arranged coaxially to the axis
of rotation 20 abuts with an inner ring surface 34 on the section
24 of the outer cylindrical surface 22 and with a projection 36
on the flat surfaces 26 so that the ring 32 is non-rotatably connected
to the stub shaft 16. The ring 32 is, for its part, provided with
a plurality of locking body mountings 40 which are arranged on a
circular line 38 at equal angular distances W1 in relation to the
axis of rotation 20 which are designed as passages through the
ring 32 and in which locking bodies 42 are located, these locking
bodies being designed as spheres and representing a first locking
element and, as illustrated in FIG. 3 having a diameter which is
greater than a thickness of the ring 32 measured in the direction
parallel to the axis of rotation 20.
The locking body mountings 40 are thereby designed such that the
locking bodies 42 are fixed in the ring 32 not only in radial direction
in relation to the axis of rotation 20 but also in azimuthal direction
and merely have the possibility of moving relative to the ring 32
in a locking direction 44 which extends parallel to the axis of
rotation 20.
An additional section 48 of the outer cylindrical surface 22 is
located on a side of the section 24 of the outer cylindrical surface
22 facing away from the first end 12. This additional section 48
guides a second coupling element which is designated as a whole
as 50 and which, as illustrated in FIG. 4 is likewise formed from
a second ring 52 which abuts on the cylindrical outer circumferential
surface 22 in the section 48 with a cylindrical inner ring surface
54 and thus is rotatable relative to the guide attachment 18 about
the axis of rotation 20 namely coaxially thereto.
The second ring 52 is thereby provided with a plurality of locking
body receiving means 58 which are arranged at the angular distance
W1 are designed as recesses in a plane surface 56 extending at
right angles to the axis of rotation 20 and facing the first coupling
element 30 and form a second locking element, the locking body receiving
means being arranged on a circular line 60 around the axis of rotation
20 which has the same radius as the circular line 38. The locking
body receiving means 58 are preferably operative over an angular
region in relation to the axis of rotation 20 and designed, for
example, in the shape of calottes or as conical depressions. It
is, however, also conceivable to design the locking body receiving
means as notches extending in a radial direction in relation to
the axis of rotation and having, for example, a V-shaped cross section.
The second ring 52 is supported with a plane surface 62 located
opposite the plane surface 56 on an axial bearing which is designated
as 64 and is again supported, for its part, on a supporting disk
66 which forms a second end 68 of the stub shaft 16.
A pressure ring, which is designated as 70 and is likewise mounted
with an inner ring surface 72 on the first section 24 of the outer
circumferential surface 22 namely for rotation relative to the
guide attachment 18 is arranged on the side of the first coupling
element 30 located opposite the second coupling element 50.
The pressure ring 70 has an annular pressure surface 74 facing
the first coupling element 30 while a contact surface 76 of the
pressure ring 70 located opposite the pressure surface is supported
on an axial bearing 80 which, for its part, is again acted upon
by a pressure disk 82 on which a stack of cup springs designated
as a whole as 84 acts, this stack of cup springs being arranged
around a bearing section 86 of the stub shaft 16 and acted upon
by an adjusting nut 88 which, for its part, is screwed onto a threaded
section 90 of the stub shaft 16. With the adjusting nut 88 it is
possible to adjust a pretension of the stack of cup springs 84 and
thus a force which extends parallel to the axis of rotation 20 and
with which the pressure ring 70 acts on the first coupling element
30 (FIG. 1).
A holding element designated as a whole as 100 (FIG. 2) is arranged
around the first coupling element 30 and this holding element has
a guide ring 102 which is guided with an inner ring surface 104
on an outer ring surface 106 of the first ring 32 coaxially to the
axis of rotation 20 and has entraining fingers 108 each of which
engages in a cutaway portion 110 set back in relation to the outer
ring surface 106 of the ring 32. Each entraining finger is rotatable
over a limited angular area WB in each of the cutaway portions 110
between side walls 111a, b of the respective cutaway portion 110
located opposite one another and preferably extending in radial
direction.
The entraining fingers 108 are, for their part, arranged at an
angular distance W2 on the guide ring 102 and engage in the respective
cutaway portions 110 of the ring 32 arranged at corresponding angular
distances so that the guide ring 102 is altogether rotatable through
the angular area WB in relation to the ring 32 of the first coupling
element 30 (FIG. 2).
Each of the entraining fingers 108 integrally formed on the guide
ring 102 is, for its part, provided with an adjusting cam mounting
112 in which an adjusting cam designated as a whole as 114 and
designed as a sphere is respectively arranged. The adjusting cam
mounting 112 is designed in the same manner as the locking body
mounting 40 as a passage through the entraining finger 108 thereby
guides the respective adjusting cam 114 such that this is movable
relative to the entraining finger 108 in an adjusting direction
116 parallel to the axis of rotation 20 but is otherwise fixed against
radial movement in relation to the axis of rotation 20 and azimuthal
movement thereto relative to the entraining finger 108.
The adjusting cam mountings 112 are preferably arranged on the
same circular line 38 as the locking body mountings 40 in the ring
32 of the first coupling element 30.
The thickness of the guide ring 102 and the entraining fingers
108 measured in the direction of the axis of rotation 20 thereby
corresponds approximately to the thickness of the ring 32 or is
slightly smaller.
Furthermore, the adjusting cams 114 designed as spheres are essentially
the same size as the spheres serving as locking bodies 42.
In addition to the locking body receiving means 58 the second
coupling element 50 likewise has adjusting cam outer supports 118
which are designed as recesses proceeding from the plane surface
56 and are at an angular distance W2 from one another and located
on the circular line 60 extending around the axis of rotation 20.
The recesses are preferably operative over an angular region in
relation to the axis of rotation 20 and can, for example, be calotte-like
or spherical depressions. It is, however, also possible to design
the recesses as notches extending in a radial direction in relation
to the axis of rotation 20 and having, for example, a V-shaped cross
section.
The adjusting cam outer supports 118 are preferably each arranged
centrally between the locking body receiving means 58 and the angular
distance W2 between the adjusting cam outer supports 118 is identical
to the angular distance W1 between the locking body receiving means
58 so that each locking body receiving means 58 follows an adjusting
cam outer support 118 at the angular distance W1/2 or W2/2 as illustrated
in FIG. 4.
In the coupled position illustrated in FIG. 3 the coupling elements
30 50 are turned relative to one another such that the locking
bodies 42 and the locking body receiving means 58 are located opposite
one another in pairs in a coupling rotary position and, consequently,
the locking bodies 42 are movable along the locking direction 44
into an operative position, in which the locking bodies 42 engage
in the locking body receiving means 58 with a lower calotte surface
120 and thus form a non-rotatable connection between the first coupling
element 30 and the second coupling element 50 which thereby interact
directly with one another. In order to maintain the operative position,
and to keep the locking bodies 42 with their calotte surfaces 120
in engagement with the locking body receiving means 58 these are
acted upon in their coupling rotary position by the pressure surface
74 of the pressure ring 70 in the region of their upper calotte
surface 122 located opposite the calotte surface 120. The locking
bodies 42 designed as spheres are therefore seated firmly in the
locking body receiving means 58 with their calotte surfaces 120
are taken along via the locking body mountings of the ring 32 and
thus follow a rotational movement of the ring 32 with the stub shaft
16 then also take along the second coupling element 50 which is
connected, for example, with a driven element 130 which engages
over the supporting disk 66 and is in non-rotatable, preferably
positive rotary connection with the second coupling element 50.
So that the force of the pressure ring 70 can act on the locking
bodies 42 in the coupling position of the locking bodies 42 relative
to the locking body receiving means 58 the holding element 100
is in its inactive position. In this inactive position, the adjusting
cams 114 serving as adjusting elements are located with their lower
calotte surfaces 124 in the adjusting cam outer supports 118 which
are likewise designed as recesses and likewise serve as adjusting
elements, the adjusting cams 114 designed as spheres likewise being
acted upon by the pressure surface 74 of the pressure ring 70 with
their calotte surfaces 126 located opposite the calotte surfaces
124. A precondition for the fact that the holding element 100 can
be located in the inactive position is that the adjusting elements
114 118 are located relative to one another and in pairs in an
initial rotary position (FIGS. 2 3) and can be brought into engagement
due to the action of the pressure ring in an adjusting direction
116. If the adjusting cams 114 are spheres having an identical diameter
to that of the locking bodies 42 and the adjusting cam outer supports
118 are of the same shape as the locking body receiving means 58
both the adjusting cams 114 and the locking bodies 42 each experience
the same action of the force via the pressure surface 74 in the
direction of the second coupling element 50.
In order to be located in the inactive position, the holding element
100 is to be turned relative to the first coupling element 30 into
the initial rotary position such that, as illustrated in FIG. 2
the adjusting cam mountings 112 are arranged at the angular distance
from the locking body mountings 40 which corresponds to the angular
distance of the adjusting cam outer supports 118 from the respectively
next adjacent locking body receiving means 58 so that in the illustrated
embodiment the adjusting cam mountings 112 are at the angular distance
W1/2 or W2/2 from the respectively next adjacent locking body mounting
40. In this position of the holding elements 100 the entraining
fingers 108 preferably abut on the side walls 111a of the cutaway
portions 110 while an angular distance corresponding to WB remains
between the entraining fingers 108 and the side wall 111b.
The inventive coupling is functionally operative when the stub
shaft 16 turns in a direction of rotation 132 the side wall 111a
being the leading side wall in the direction of rotation 132 and
the side wall 111b the trailing side wall in the direction of rotation
132.
If the driven element 130 is now, for example, blocked in its rotational
movement or this experiences at least a sufficiently large countertorque,
a so-called unlocking torque of the coupling 10 is exceeded, the
conditions immediately following a blocking of the driven element
130 being illustrated in FIG. 5.
If the first coupling element 30 continues to turn in the direction
of rotation 132 relative to the second coupling element 50 proceeding
from the coupling rotary position when the driven element 130 is
blocked and thus the second coupling element 50 is also blocked
with respect to its rotational movement, this leads to the locking
bodies 42 leaving the locking body receiving means 58 due to their
calotte surface 120 which acts as an inclined surface. This does,
however, cause the locking bodies 42 to act on the pressure surface
74 of the pressure ring 70 with their calotte surfaces 122 contrary
to the force of the stack of cup springs 84 and to move the pressure
ring 70 away from the second coupling element 50 while leaving the
locking body receiving means 58 namely as far as a distance between
plane surface 56 and pressure surface 74 which corresponds to the
diameter of the locking bodies 42 designed as spheres (FIG. 5).
This means that there is now no non-rotational connection between
the first coupling element 30 and the second coupling element 50.
In this respect, the first coupling element 30 moves further in
the direction of rotation 132 and the locking bodies 42 thereby
roll along the plane surface 56 so that the pressure ring 70 likewise
turns in the direction 132 but with double the speed of the first
coupling element 30 since the locking bodies 42 designed as spheres
roll along the stationary plane surface 56 of the second coupling
element 50. This rotational movement of the first coupling element
30 relative to the second coupling element 50 has no influence on
the holding element 100 for as long as the clearance of WB between
the entraining finger 108 and a respectively trailing side wall
111b, in the direction of rotation, of the respective cutaway portion
110 receiving the entraining finger 108 exists due to the size of
the cutaway portions 110 and, consequently, the holding element
100 remains in the initial rotary position relative to the second
coupling element 50. If this clearance no longer exists due to the
further rotation of the ring 32 in relation to the stationary guide
ring 102 and the trailing side wall 111b, in the direction of rotation,
abuts on the respective entraining finger 108 (FIG. 6), the holding
element 100 is taken along in the direction of rotation 132 by the
rotational movement of the first coupling element 30 and leaves
the initial rotary position relative to the second coupling element
50. In this respect, the adjusting cams 114--as illustrated in FIG.
7--can run out of the adjusting cam outer supports 118 without any
problem since the upper calotte surface 126 of the adjusting cams
114 designed as spheres is no longer acted upon by the pressure
surface 74 of the pressure ring 70 and so the adjusting cams 114
designed as spheres likewise roll along the plane surface 56 after
leaving the adjusting cam outer supports 118.
Due to the removal of the clearance between the side wall 111b
of the respective cutaway portion 110 and the respective entraining
finger 108 a limited relative rotation of the holding element 100
has taken place relative to the first coupling element 30 (FIG.
6) and so the adjusting cam mountings 112 are no longer at an angular
distance W1/2 or W2/2 in relation to the respectively following
locking body mounting 40. This means that a distance between the
pressure surface 74 of the pressure ring 70 and the plane surface
56 of the second coupling element 50 is maintained either by the
locking bodies 42 or the adjusting cams 114 and so, on the one hand,
when the locking bodies 42 are in the coupling rotary position over
the locking body receiving means 58 the pressure ring 70 cannot
move these in the locking direction 44 into the locking body receiving
means 58 (FIG. 8) and, on the other hand, the pressure ring 70 cannot
move the adjusting cams 114 designed as spheres in the adjusting
direction 116 into the adjusting cam outer supports 118 even when
the initial rotary position between holding element 100 and second
coupling element 50 is reached (FIG. 7).
As a result of the locking body receiving means 58 and adjusting
cam outer supports 118 preferably being operative over an angular
region, the locking bodies 42 and the adjusting cams 114 are in
a supporting condition together (e.g., wherein the locking bodies
42 support rotational movement of the first coupling element 30
relative to the second coupling element 50 and the adjusting cams
114 support rotational movement of the holding element 100 relative
to the second coupling element 50) only over a narrow angular region
of less than 5.degree., preferably 2.degree., during a rotation
of the first coupling element 30 in relation to the second coupling
element 50; in all the other rotary positions either the locking
bodies 42 are in a coupling rotary position or the adjusting cams
114 are in an initial rotary position relative to the second coupling
element.
This means that when the stub shaft 16 continues to be driven the
coupling remains released and due to the rolling movement of the
locking bodies 42 and adjusting cams 114 the first coupling element
30 and the holding element 100 taken along by it are rotatable without
any appreciable countertorque in an unlimited manner in relation
to the second coupling element 50.
The coupling 10 is thus released for such a time until a drive
of the stub shaft 16 is interrupted and a rotation of the stub shaft
16 in a direction of rotation 142 contrary to the direction of
rotation 132 takes place. The first coupling element 30 is thereby
rotated in relation to the holding element 100 contrary to the direction
of rotation 132 to such an extent that the entraining fingers 108
move away from the trailing side wall 111b, in the direction of
rotation 132 and namely for such a time until these again abut
on the leading side wall 111a, in the direction of rotation 132
(FIG. 2). In this position of the entraining fingers 108 the locking
bodies 42 and the adjusting cams 114 are again at an angular distance
W1/2 or W2/2 and so when the coupling rotary position is reached,
i.e. congruent position of the locking bodies 42 with the locking
body receiving means 58 in pairs, and at the same time the initial
rotary position is possibly reached, i.e. congruent position of
the adjusting cams 114 with the adjusting cam outer supports 118
in pairs, these are brought into engagement again with one another
under the influence of the force of the stack of cup springs 84
and the coupling position according to FIG. 3 is reached.
The transition from the uncoupled position into the coupled position
is facilitated by the fact that the locking bodies 42 and the adjusting
cams 114 are in supporting condition together only over a narrow
angular region and therefore during rotation contrary to the direction
of rotation 132 a slight relative rotation between first coupling
element 30 and holding element 100 is adequate to bring both into
the coupling rotary position and initial rotary position at the
same time.
If the coupling 10 is intended to be designed such that a transition
from the coupled position into the uncoupled position takes place
independently of the drive direction of rotation, the cutaway portions
110 are to be designed such that the entraining fingers 108 engaging
in them can move in both directions of rotation with clearance WB
proceeding from the initial rotary position of the holding element
100. This means that the inactive rotary position relative to the
first coupling element 30 is no longer defined by the side wall
111a but only by the adjusting cam outer supports 118 whereby the
inactive rotary position can be reached reliably due to the, for
example, V-shaped or conical design of the adjusting cam outer supports
118 extending over an angular region, in particular with a, for
example, V-shaped or conical design of the locking body receiving
means 58 likewise extending over an angular region.
To summarize, the inventive coupling 10 can thus be transferred
from the coupled (FIG. 3) into the uncoupled position (FIGS. 7
8) when the unlocking torque is exceeded without any appreciable
countertorque occurring in this uncoupled position between the first
coupling element 30 and the second coupling element 50 due to the
locking elements 42 58 touching.
The embodiment of an inventive coupling 10 illustrated in FIG.
1 represents an assembly for machine tools which can be used separately,
with, for example, the machine tool which is not illustrated in
the drawings driving the stub shaft 16 at the first end with its
driven shaft and a rotating tool, preferably a rotating cutting
tool, for example a drill bit, being driven via the driven element
130 directly or indirectly.
The inventive coupling 10 designed as a separate assembly can,
however, also be used in the reverse manner, i.e. a drive can take
place via the driven element 130 and a tool can be driven via the
stub shaft 16.
In this case, the inventive coupling likewise functions in the
manner described in the above, with the difference that the drive
element has to be driven with a direction of rotation 142 which
extends exactly opposite to the direction of rotation 132. In this
case, the first coupling element 30 remains stationary when the
rotational movement of the stub shaft 16 is blocked whereas the
second coupling element 50 continues to move, whereby the locking
bodies 42 likewise move the pressure ring 70 away from the second
coupling element 50. In addition, the holding element 100 first
of all moves with the second coupling element 50 in the direction
of rotation 142 for such a time until the entraining fingers 108
abut on the side walls 111b. In this position, the holding element
100 and the first coupling element 30 are, in the same manner as
described in detail in the above, turned in relation to one another
to such an extent that the inventive coupling 10 remains in its
uncoupled position for such a time until a drive of the driven element
130 is interrupted and the driven element 130 is rotated contrary
to the direction of rotation 142.
In a second embodiment 210 of an inventive coupling, this is integrated
into a machine tool designated as a whole as 160 and illustrated
schematically.
The machine tool comprises a drive motor 162 which is accommodated
in a housing 164 of the machine tool and has a driven shaft 166
which, for its part, is again mounted in the housing 164 via a bearing
168 and on which a gear wheel 170 is seated which meshes with an
outer toothing 172 of the second coupling element 250. In this second
embodiment 210 of the inventive coupling, the stub shaft 216 is
mounted in the housing 164 at its first end 212 and with a cylindrical
section 267 following the supporting disk 266 and following the
cylindrical section 267 is rigidly connected with a drilling tool
174 preferably a drill bit.
In contrast to the first embodiment, a drive is thus carried out
in the second embodiment 210 of the inventive coupling by means
of the drive motor 162 via the second coupling element 250 whereas
the first coupling element 30 which is non-rotatably connected to
the stub shaft 216 then drives the tool 174 via the stub shaft 216.
The second embodiment 210 of the inventive coupling operates in
the same manner as that described in conjunction with the drive
of the first embodiment 10 of the inventive coupling via the driven
element 130 in the direction of rotation 142.
In the second embodiment of the inventive coupling 210 illustrated
in FIG. 9 the second coupling element is, in contrast to the first
embodiment 10 of the inventive coupling, provided with a recess
which is designated as a whole as 176 and the bottom surface 178
of which forms the plane surface 56 described in conjunction with
the first embodiment 10 the locking body receiving means and the
adjusting cam outer supports likewise being integrally formed as
additional recesses.
The first coupling element 30 the pressure ring 70 the axial
bearing 80 and the pressure disk 82 are then inserted into the recess
176 so that these are arranged in a space-saving manner and additionally
enclosed in the second coupling element 250. The stack of cup springs
84 which is arranged to follow the second coupling element 250
and is seated on the stub shaft 216 and which, for its part, is
again supported on the adjusting nut 88 acts on the pressure disk
82.
In addition, rollers are used as rolling bodies in the second embodiment
210 of the inventive coupling instead of the locking bodies 42 and
the adjusting cams 114 designed as spheres and these rollers are
rotatable about an axis extending radially to the axis of rotation
20 of the stub shaft 16.
With respect to the remaining features and functions of the second
embodiment, reference is made in full to the explanations concerning
the first embodiment.
In a third embodiment of an inventive coupling 310 illustrated
in FIG. 10 this is driven and the tool is driven by means of this
coupling 310 in the same manner as that described in conjunction
with the second embodiment and so the same reference numerals are
used for the same parts and reference is made in full to the description
of these parts in conjunction with the second embodiment.
In the third embodiment 310 of the inventive coupling, as illustrated
in FIG. 11 an elevation 342 is, for example and in contrast to
the first and second embodiments, integrally formed in one piece
on the first ring 32 instead of a sphere as locking body and so
the locking body mountings 40 can also be omitted. In addition,
an elevation 414 is likewise integrally formed, for example, in
one piece on the respective entraining finger 108 instead of an
adjusting cam 114 designed as a sphere and so the adjusting cam
mountings 112 can also be omitted. The locking bodies 342 and the
adjusting cams 414 are, however, still located, as illustrated in
FIG. 12 on the circular line 348 around the axis of rotation 20.
In addition, the locking bodies 342 are arranged at angular distances
W1 on the first ring 32 and the adjusting cams 414 at angular distances
W2 on the entraining fingers 108 of the guide ring 102.
The locking body receiving means 358 and the adjusting cam outer
supports 418 are arranged at the same angular distances W1 and W2
respectively, in the plane surface 56 of the second coupling element
350 of the inventive coupling, in the same manner as in the first
embodiment, the locking body receiving means 358 and the adjusting
cam outer supports 418 thereby being adapted in their shape to the
locking bodies 342 and the adjusting cams 414 respectively. The
locking bodies 342 and the adjusting cams 414 preferably have the
same, essentially triangular cross section when considered in a
radial direction in relation to the axis of rotation 20.
In contrast to the first and second embodiments, it is provided
in the third embodiment for the pressure ring 70 to act with its
pressure surface 74 directly on the first ring 32 or the guide ring
102 with the entraining fingers 108 namely on their respective
surfaces located opposite the locking bodies 342 and adjusting cams
414.
The third embodiment of the inventive coupling operates as described
in conjunction with the first embodiment 10 of the inventive coupling
in the case of a drive via the driven element 130.
As illustrated in FIG. 13 the second coupling element 350 continues
to rotate when the stub shaft 316 is blocked and thus the first
coupling element 30 is likewise blocked, whereby the locking bodies
342 slide out of the locking body receiving means 358 and move the
pressure ring 70 away from the plane surface 56 of the second coupling
element 350 contrary to the force of the stack of cup springs 84.
This means that the second coupling element 350 continues to rotate
in the direction of rotation 142. During this rotation, the second
coupling element takes along the holding element 100 which first
of all engages with the adjusting cams 414 in the adjusting cam
outer supports 418 for such a time until the entraining fingers
108 come to rest on the side walls 111b of the cutaway portions
110 (FIG. 14).
This means that the holding element 100 is rotated relative to
the first coupling element 30 to such an extent that the entrainment
of the holding element 100 by the second coupling element 350 is
blocked and thus the adjusting cams 414 also disengage from the
adjusting cam outer supports 418 and the holding element 100 is
likewise moved as a whole away from the second coupling element
350 and abuts with its surface located opposite the adjusting cams
414 on the pressure surface 74 of the pressure ring 70 as illustrated
in FIGS. 14 to 16. In this active rotary position of holding element
100 and first coupling element 30 the coupling remains in its uncoupled
position.
In contrast to the first two embodiments, a sliding friction occurs
between the locking bodies 342 acted upon by the force of the stack
of cup springs 84 or the adjusting cams 414 and the plane surface
56 of the second coupling element 350 in the released position of
the coupling and so the countertorque is greater than during the
rolling friction due to the rolling bodies of the first or second
embodiment.
The coupling moves into the coupled position in the same way as
that described in conjunction with the first embodiment during the
drive via the driven element 130. As for the rest, reference is
made in full to the description of the first and second embodiments
with respect to the construction and functioning of the individual
components. |