U.S. patent application number 10/560875 was filed with the patent office on 2006-08-17 for manipulator-guided gripping device having a deflection safety device that can prevent collisions.
Invention is credited to Botho Kikut, Elmar Nuchter.
Application Number | 20060181092 10/560875 |
Document ID | / |
Family ID | 33553661 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060181092 |
Kind Code |
A1 |
Kikut; Botho ; et
al. |
August 17, 2006 |
Manipulator-guided gripping device having a deflection safety
device that can prevent collisions
Abstract
A manipulator-guided gripping device (1) for motor vehicle body
parts includes a number of device parts (6, 7) and a safety device
(9), which serves to determine geometrical changes of the device
parts (6, 7, 8). At least one deflection safety device (10), which
prevents collisions, is provided on the device parts (6, 7, 8). The
deflection safety device (10) is mounted on a junction point (23)
between the device parts (6, 7, 8).
Inventors: |
Kikut; Botho; (Augsburg,
DE) ; Nuchter; Elmar; (Augsburg, DE) |
Correspondence
Address: |
MCGLEW & TUTTLE, PC
P.O. BOX 9227
SCARBOROUGH STATION
SCARBOROUGH
NY
10510-9227
US
|
Family ID: |
33553661 |
Appl. No.: |
10/560875 |
Filed: |
June 7, 2004 |
PCT Filed: |
June 7, 2004 |
PCT NO: |
PCT/EP04/06113 |
371 Date: |
December 13, 2005 |
Current U.S.
Class: |
294/2 |
Current CPC
Class: |
B25J 15/0061 20130101;
B25J 19/063 20130101; B25J 15/0052 20130101 |
Class at
Publication: |
294/002 |
International
Class: |
A47G 21/10 20060101
A47G021/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2003 |
DE |
203 09 435.2 |
Sep 24, 2003 |
DE |
203 14 896.7 |
Claims
1. A manipulator-guided gripping device for workpieces and body
parts in a body shell, the gripping device comprising: a plurality
of device parts; a safety means for detecting changes in geometry,
including at least one deflectable safety device at the device
parts.
2. A gripping device in accordance with claim 1, wherein the
deflectable safety device is arranged at a junction point between
the device parts.
3. A gripping device in accordance with claim 1, wherein the
deflectable safety device has at least two said safety device parts
that are mounted such that they can deflect along one or more axes
in case of overload.
4. A gripping device in accordance with claim 3, wherein the safety
device parts are connected to one another by clamping connection
and frictional connection.
5. A gripping device in accordance with claim 3, wherein the safety
device parts are connected to one another in a positive-locking
manner by at least one said deflectable locking element.
6. A gripping device in accordance with claim 3, wherein the safety
device parts are connected to a device part each.
7. A gripping device in accordance with claim 5, wherein the
locking element is arranged between the safety device parts.
8. A gripping device in accordance with claim 5, wherein the
locking element is held with an elastic clamping element.
9. A gripping device in accordance with claim 8, wherein the
locking element and the clamping element are set to a force that
holds the safety device parts during normal operation.
10. A gripping device in accordance with claim 1, wherein the
safety device parts are designed as a sphere and as a socket
surrounding same.
11. A gripping device in accordance with claim 10, wherein the
sphere is designed as a joint ball and the socket is designed as a
straight tube section.
12. A gripping device in accordance with claim 10, wherein the
sphere is designed as a ring-shaped collar with a spherical outer
side and the socket is designed as a calotte surrounding same with
an inner side rounded in a complementary manner.
13. A gripping device in accordance with claim 12, wherein the
collar and the calotte surrounding same have essentially the same
width.
14. A gripping device in accordance with claim 3, wherein the
safety device parts are designed as disk mounts with parallel
working surfaces.
15. A gripping device in accordance with claim 3, wherein the
safety device parts have an adjusting means for reproducible mutual
positioning.
16. A gripping device in accordance with claim 3, wherein the
safety device parts have one or more detectors, which detect and
signal deflections of the safety device parts.
17. A gripping device in accordance with claim 16, wherein the
detector is arranged eccentrically in relation to the central axis
of the safety device parts.
18. A gripping device in accordance with claim 16, wherein the
detector is arranged centrally in the central axis of the safety
device parts the safety device parts have an adjusting means for
reproducible mutual positioning and the detector is designed as a
part of the adjusting means.
19. A gripping device in accordance with claim 18, wherein the
detector has a pressure piece, which is mounted in an elastically
movable manner in an end-side tube section of the shaft and whose
projecting head part engages a mount at a projection of the other
safety device part in a positive-locking manner, wherein a
microswitch is arranged at the contact point.
20. A gripping device in accordance with claim 16, wherein the
detectors are connected to a process control.
21. A gripping device in accordance with claim 1, further
comprising: a frame with one or more said gripping or clamping
elements and with a docking point for connection to a mechanical
manipulator in the form of a multiaxial industrial robot.
22. A gripping device in accordance with claim 1, wherein the frame
has a plurality of said frame tubes.
23. A gripping device in accordance with claim 15, wherein the
frame tubes are divided and wherein a deflectable safety device is
arranged between the tube sections.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a United States National Phase
application of International Application PCT/EP2004/006113 filed
Jun. 7, 2004 and claims the benefit of priority under 35 U.S.C.
.sctn. 119 of German Application DE 203 09 435.2 filed Jun. 17,
2003 and DE 203 14 896.7 filed Sep. 24, 2003, the entire contents
of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention pertains to a manipulator-guided
gripping device for workpieces, especially body parts in the body
shell, wherein the gripping device has a plurality of device parts
and a safety means for detecting changes in geometry.
BACKGROUND OF THE INVENTION
[0003] Such a gripping device for vehicle body parts in body
framing and paneling is known from DE 200 04 369 U1. The gripping
device is guided by a multiaxial industrial robot. Such devices are
used in partially or fully automatic plants or cells for body
framing and paneling or in other technical areas. Collisions and
crashes may occur here, in which the gripping device may be
damaged. Such damage leads mostly to a change in geometry. For
example, gripping parts that are relevant for function or the
component, for example, tensioners, grippers, alignment pins or
shearing pins, centering pins or the like may now be bent, twisted
or brought out of their desired position in another way. This may
also happen due to deformation of the gripper frame. Crashes are
recognized and reported in practice by monitoring the motor current
of the robot axis drives. However, this operates reliably only in
case of violent collisions, which propagate to the robot drive.
Minor collisions with weaker forces, which are mostly absorbed
extensively by the yielding of the gripping device or parts
thereof, cannot be recognized by monitoring the motor current.
However, such minor collisions nevertheless lead to damage to and
malfunction of the gripping device, which in turn entails errors in
the machining process and on the body shell. In case of the
above-mentioned major collisions, which are detected and signaled
by monitoring the motor current, the gripping device is replaced
and repaired. The gripping device must be removed to identify and
repair the unknown damage, set up completely and remeasured. This
is a very complicated operation and can be carried out only outside
the gripper operation.
SUMMARY OF THE INVENTION
[0004] An object of the present invention is to provide a gripping
device that exhibits better behavior in case of crashes and
collisions.
[0005] According to the invention, a manipulator-guided gripping
device is provided for workpieces such as body parts in a body
shell. The gripping device has a plurality of device parts and a
safety means for detecting changes in geometry with at least one
deflectable safety device at the device parts. The deflectable
safety device is provided at the various components or parts of the
gripping device. The safety device is preferably present as
multiple devices to provide the advantage that it makes possible
the deflection of the colliding parts of the gripping device in
case of a crash or collision, as a result of which plastic
deformations and other damage are avoided on the gripping device.
Due to the deflected position, it is, moreover, optically signaled
to an operator that a collision has taken place. In addition,
suitable detectors or sensors may be present at the deflectable
safety device, which detect a deflecting movement and report it in
a suitable manner, for example, signal it to a process control,
automatically trigger an alarm or the like.
[0006] The deflectable safety device is preferably arranged at a
connection point between the different device parts of the gripping
device. The device parts, for example, frame tubes, may also be
divided, in which case a deflectable safety device is arranged
between the tube sections. The deflectable safety device may be
located as a result at the points of the gripping device that have
been shown by experience to be loaded most heavily and are also
critical. Depending on the geometry of the gripping device, the
positions of the different deflectable safety devices are selected
to be such that the colliding device part can be deflected
immediately in case of a collision, and deformations and damage are
avoided in this part as well as on the other components of the
gripping device.
[0007] The deflectable safety device may connect the device parts
with clamping and frictional connection or with deflectable
positive-locking connection. An adjusting means makes possible the
reproducible positioning of the device parts in the initial device
and also during the repositioning after a crash. The detector may
be a part of the adjusting means. The moving device part can again
be returned into its desired position after the deflection. As a
result, the gripping device can continue to be used without
complicated measurement and resetting.
[0008] If the deflectable safety device is provided with a locking
element for positive-locking guiding, it is thus also possible to
exactly define the desired position and to position the device
parts. The locking element is preferably spring-loaded, and the
overload or load threshold generated by collision, beginning from
which deflection is to take place, can be set by means of the
spring mounting. The deflectable safety device is rigid and
dimensionally stable below this threshold, so that it does not
compromise the function and the geometry of the gripping device.
The holding frictional force can be set by a controlled clamping
connection in case of a frictionally engaged connection.
[0009] From a design viewpoint, the deflectable safety device may
have various designs. It preferably comprises at least two safety
device parts, which may be designed, for example, as a sphere each
with a socket surrounding it or as disk mounts with parallel
working surfaces. A plurality of locking elements, which may be
designed, for example, as spring-loaded balls or the like, are
preferably located between the safety device parts. By selecting
the geometry of the safety device parts and of the locking elements
correspondingly, the deflectable safety device can make possible
deflection along one or more defined axes in case of a
collision.
[0010] The present invention is schematically shown in the drawings
as an example. The various features of novelty which characterize
the invention are pointed out with particularity in the claims
annexed to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the drawings:
[0012] FIG. 1 is a side view of a robot with a gripping device with
a plurality of deflectable safety devices;
[0013] FIG. 2 is a top view of the gripping device according to
arrow II in FIG. 1;
[0014] FIG. 3 is a longitudinal sectional view of a variant of the
deflectable safety device;
[0015] FIG. 4 is a longitudinal sectional view of another variant
of the deflectable safety device;
[0016] FIG. 5 is a longitudinal sectional view of another design
variant of the deflectable safety device;
[0017] FIG. 6 is a cross sectional view of the design variant of
the deflectable safety device of FIG. 5;
[0018] FIG. 7 is a longitudinal sectional view of another design
variant of the deflectable safety device;
[0019] FIG. 8 is a cross sectional view of the design variant of
the deflectable safety device of FIG. 7;
[0020] FIG. 9 is a longitudinal sectional view of another design
variant of the deflectable safety device;
[0021] FIG. 10 is a cross sectional view of the design variant of
the deflectable safety device of FIG. 9; and
[0022] FIG. 11 is a cut-away side view of the adjusting means and
of the detector of the third variant according to FIGS. 9 and
10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Referring to the drawings in particular, FIG. 1 shows a
schematic side view of a machining station for workpieces, which
are held and guided by a mechanical manipulator (2) by means of a
gripping device (1). The workpiece, which is not shown for
clarity's sake, may be of any desired type whatsoever. It is
preferably a body part of a body shell, for example, a side panel
part or the like. The manipulator (2) is preferably designed as a
multiaxial industrial robot, especially as a six-axis articulated
arm robot. The workpieces can be picked up, transported, brought
into defined positions and locations and aligned as well as again
deposited with the gripping device (1). These manipulation
processes can take place fully automatically by means of a control
(26). This is, e.g., a process control, which is integrated in the
robot control. As an alternative, it may also be arranged
externally. It may also be located at the gripping device (1)
according to FIG. 2.
[0024] FIG. 2 shows a bottom view of an exemplary embodiment of a
gripping device. The gripping device (1) may be designed
corresponding to DE 200 04 369 U1 and has a frame (4), which can be
detachably connected to the robot hand (3) by means of a usually
central docking part (5). The frame (4) comprises, for example, a
plurality of frame tubes (7, 8) or other support elements, which
may be arranged in parallel as a lightweight supporting frame and
cross-connected to one another at a plurality of points. The tubes
(7, 8) are connected to the docking point (5) designed as a support
plate by means of clamps or the like. Clamping elements, gripping
elements, component centering means or the like, which assume a
gripping or guiding function, are arranged at the frame (4) and the
tubes (7, 8) thereof at a plurality of points. These may be, for
example, tensioners with contour support elements, vacuum grippers
or other similar elements. The frame tubes and the tensioners,
grippers and the like will hereinafter be called uniformly device
parts (6, 7, 8).
[0025] The gripping device (1) is designed, for example, as a
so-called geogripper, in which all device parts (6, 7, 8) have an
exactly defined position and orientation. The geogripper is exactly
adapted to the geometry of the workpiece to be manipulated.
[0026] The gripping device (1) has a safety means (9), which
responds in case of a crash and collisions with the external
environment. The safety means (9) has at least one, preferably a
plurality of deflectable safety devices (10), which are arranged at
the device parts (6, 7, 8) and permit the deflection thereof in
case of a collision. The deflectable safety devices (10) are
arranged at a junction point (23) between the device parts (6, 7,
8).
[0027] Such junction points (23) are, for example, the connection
points at which the device parts (6), i.e., the tensioners,
grippers, component centering means or the like are connected to
the frame (4). The deflectable safety device (10) is arranged here
between the device part (6) and the frame (4). Other junction
points (23) with a deflectable safety device (10) are located at
the points of intersection of the frame tubes (7, 8), where these
are connected to one another. On the other hand, one or more frame
tubes (7, 8) may also be divided, in which case two, preferably
aligned tube sections (7', 7'') are arranged at the junction or
junction point (23) at the deflectable safety device (10). Such
divisions of the tube may be present at the points of the gripping
device (1) that experience has shown to be subject to higher loads
and are located, for example, at the tube sections projecting away
from the docking plate (5). It is possible in another variant to
provide the connection points between the frame (4) or the frame
tubes (7, 8) with the docking point (5) with deflectable safety
devices (10).
[0028] The deflectable safety devices (10) are rigid and
dimensionally stable during normal operation. They withstand all
the static and dynamic loads occurring during normal operation. The
deflectable safety device responds only when a collision of the
gripping device (1) with an obstacle occurs and collision forces or
overload develops, and the deflectable safety device now permits
the deflection of the colliding device part (6, 7, 7', 7'', 8).
[0029] The deflectable safety device (10) comprises at least two
safety device parts (11, 12), which are mounted at each other such
that they can be deflected in case of overload. The safety device
parts (11, 12) may be connected by positive-locking connection as
in the variants according to FIGS. 3 through 6 or by frictional
connection according to the embodiment shown in FIGS. 7 and 8. An
adjusting means (33) makes possible the reproducible mutual
positioning of the safety device parts (11, 12) and consequently
also of the corresponding device parts (6, 7, 7', 7'', 8).
[0030] The positive-locking deflectable safety devices (10)
according to FIGS. 3 through 6 are provided with a locking element
(13), which makes possible the controlled deflection function and
also acts as an adjusting means (33). The locking element (13) is
preferably acted on by an elastic clamping element (20), which is
adjustable.
[0031] The locking element (13) is located between the safety
device parts (11, 12). The safety device parts (11, 12) are in turn
connected to a device parts [sic--Tr.Ed.] (6, 7, 8). This
connection is exactly defined geometrically and can be set exactly,
for example, by means of positioning pins (29), shearing pins or
the like. The safety device parts (11, 12) can likewise be
positioned exactly in relation to one other by means of the locking
elements (13) and are secured and held in their positions by the
locking element (13) and/or the clamping element (20). The force of
the clamping element (20) can be set and is adjusted in the
above-mentioned manner to the static and dynamic forces acting
during normal operation. The safety device parts (11, 12) yield in
relation to one another only when a force threshold, which may
optionally be set with a safety margin, is exceeded. The deflecting
movement may take place along one or more axes depending on the
embodiment of the safety device parts (11, 12) and of the locking
element (13).
[0032] FIGS. 3 and 4 show two examples of design embodiments for a
deflectable, positive-locking deflectable safety device (10), in
which there are possibilities of deflection along four separate
axes, which are illustrated in the drawings on the side by arrows.
FIGS. 3 and 4 show the example of use at a junction point (23)
between two tube sections (7', 7''). A corresponding design
embodiment may also be present at other junction points (23), for
example, between the device parts (6), i.e., the tensioners,
grippers or the like, and the frame (4) or at points of
intersection of the frame tubes (7, 8).
[0033] In the variant according to FIG. 3, a safety device part
(12) associated with the tube section (7'') is designed as a
sphere, namely, as a joint ball (15), which is attached to the tube
end. A ring (15') with spherical circumference according to the
variants of FIGS. 5 through 8 described below or another spherical
part may also be used instead of a joint ball (15). The second
safety device part (11) connected to the other tube section (7') by
means of a metal fitting is designed as a socket (14), which
surrounds and holds the joint ball (15) on the circumference. The
socket (14) may have a straight tubular shape with a cylindrical or
prismatic cross section, so that a linear contact with the
circumference of the ball is possible with the joint ball (15).
[0034] The socket (14) and the joint ball (15) are held in contact
with one another by the locking element (13), which comprises in
this case a plurality of locking balls (18), which are distributed
on the circumference in the contact area and are acted on by a
pressing spring (22) each as a clamp, tensioner or clamping element
(20). The locking balls (18) engage correspondingly shaped, exactly
defined mounts (19) at the socket (14) and the joint ball (15) and
thus secure the connection. Such ball/spring units may be screwed
as ready-made machine parts into the socket (14). At least three,
preferably four locking balls (18) are arranged in a uniformly
distributed manner over the circumference of the ball on a line at
right angles to the longitudinal axis of the tube section.
[0035] When, for example, an upsetting or tensile force develops
along the central axis of the two, preferably aligned tube sections
(7', 7''), the tube section (7'') with the joint ball (15) can be
pulled out of or pushed into the socket (14) when the force acting
is greater than the resultant, acting in the same direction, from
the holding force of the radially acting springs (22). The socket
(14) has a sufficient clearance at the bottom against the joint
ball (15) to absorb upsetting forces and upsetting movements. If,
on the other hand, lateral forces act on one of the tube sections
(7', 7''), the joint ball (15) can rotate correspondingly in the
socket (14) about the vertical and/or horizontal axis for
deflection. Torsional forces can also be absorbed by a deflecting
movement and rotation about the longitudinal axis of the tube.
[0036] The mounts (19) may be designed with precision such that
they permit the ball (18) to snap in only when it is in the exact
position. As a result, a deflecting movement in case of collision
is not abolished and returned by itself. The device parts (6, 7, 8)
stop in the deflected position in relation to one another. The
desired position and the locked position can, however, be restored
by an operator by manual engaging. As soon as all locking balls
(18) engage their respective mounts (19), the desired position is
exactly restored.
[0037] As an alternative, the mounts (19) may have an expanded
shape at one of the safety device parts, for example, the joint
ball (15), and form, for example, recesses or pans (28) with an
enlarged radius of curvature. In case of such a shape or another
suitable shape, the deflecting device part (6, 7, 7', 7'', 8) can
snap back by itself into the desired position after the
collision.
[0038] As is also illustrated in FIG. 3, the deflectable safety
device (10) may have one or more detectors (24), which detect a
possible deflecting movement and signal it in a suitable manner.
They can report it to the control (26), for example, via the lines
(25) shown in FIG. 1. The detectors (25) may be designed, for
example, as pressure sensors, which are associated with one or more
locking balls (18) and record the movement behavior of these balls.
The detectors (24) may otherwise be designed in any desired and
suitable manner as force, motion or distance sensors or the
like.
[0039] According to FIG. 2, the control (26) may have a plurality
of displays (41), whose number corresponds to the number of
detectors, e.g., optical displays, for signaling the detector
function and a possible deflection. As an alternative, the displays
may be located at another point, e.g., at the deflectable safety
devices (10). As a result, the operator can immediately locate the
deflection point.
[0040] In the variant according to FIG. 4, the two safety device
parts (11, 12) comprise two disk mounts (16, 17), between the
parallel working surfaces of which, which face each other, the
locking element (13) is arranged in the form of a plurality of
locking balls (18) distributed in a circle. The locking balls (18)
are preferably located in a common plane, in which the central axis
of the two, preferably aligned tube sections (7', 7'') is also
located. At least three, preferably four or more locking balls (18)
are arranged, distributed in a ring, in this case as well. The disk
mounts (16, 17) have corresponding conical mounts (19) or mounts of
another shape on their working surfaces for the centered mounting
and guiding of the locking balls (18).
[0041] The clamping element (20) is designed in this variant as a
tightening screw (21) with a spring (22), which extends centrally
and at right angles through the ball ring. It extends in two
aligned mounting holes of the disk mounts (16, 17). The mounting
holes have a larger diameter than the shaft of the screw, which is
guided at the ends of the hole by half shell-shaped insert
elements, which are in contact with the screw head, on the one
hand, and with the spring (22), on the other hand. The two disk
mounts (16, 17) are connected to the tube sections (7', 7'') by
corresponding metal fittings (27) in a geometrically defined
position.
[0042] Possibilities of deflection along the four axes explained in
the exemplary embodiment according to FIG. 3 are present in the
variant according to FIG. 4 as well. To absorb upsetting forces,
the tube sections (7', 7'') have a sufficient distance from the
respective other disk mount (16, 17) at their ends. Moreover, a
possibility of deflection along the other two translatory axes in
the vertical and horizontal directions (out of the drawing plane)
is also given in the embodiment according to FIG. 4.
[0043] Detectors (24) of the above-described type may likewise be
present in the deflectable safety device (10) according to FIG. 4.
They are not shown in the drawing for clarity's sake only.
[0044] FIGS. 5 through 11 show three variants of the deflectable
safety device (10), which is especially suitable for the crossed
connection of device parts (6, 8), especially of tensioners or
grippers or component centering means, etc., with frame tubes. The
shaft or post (37) of the tensioners or grippers (6) is shown in
the drawings.
[0045] The two safety device parts (11, 12) of the deflectable
safety device (10) are of a similar design in the three variants,
there being a positive-locking guiding with a spring-loaded locking
element (13) in the exemplary embodiment according to FIGS. 5 and 6
and a frictionally engaged guiding in the variants according to
FIGS. 7, 8 and FIGS. 9 through 11. A frictionally engaged guiding
may also be present and act primarily in the variant according to
FIGS. 5 and 6 as well, especially in case of locking springs set to
a weak force.
[0046] One safety device part (12) is provided with the sphere as a
ring-shaped collar (15') with an outer edge rounded in a spherical
form in the three variants. The collar (15') is connected to the
shaft (37) and is preferably made in one piece with it. The
spherical rounding has the shape of a spherical segment, whose
center (40) is the intersection of the central shaft axis (38) with
the central plane of the ring collar (15'), which said central
plane is located at right angles.
[0047] The second safety device part (11) is connected to the frame
tube (8) or another device part in a suitable manner, e.g., by a
clamp-like metal fitting (27) with exact positioning and optionally
a positioning pin (29). The safety device part (11) has a socket,
which is designed as a ring-shaped calotte (14') and has an inner
side rounded in a complementary and spherical manner. The rounding
is designed as a spherical segment surface with the center (40) in
this case as well. Due to this design, the safety device parts (11,
12) can rotate with their device parts (6, 8) about the center (40)
in the manner indicated by arrows in FIG. 5 when the deflectable
safety device (10) responds. Axial displacement in the direction of
the shaft axis (38) is not possible due to the connection between
the safety device parts (11, 12), which is a positive-locking
connection due to the spherical section shape.
[0048] To make it possible to mount the safety device parts (11,
12), the calotte (14') has a multipart design and comprises, e.g.,
two shell parts (30, 31), which meet at a transverse plane
extending through the center (40) and can be connected and
tightened by means of screws (32). Ground fitting plates are
inserted at the contact point for an exact fit. This embodiment is
again the same in the three embodiments according to FIGS. 5
through 11.
[0049] A locking element (13) is present in the variant according
to FIGS. 5 and 6 for the positive-locking connection of the safety
device parts (11, 12). It comprises, e.g., three locking balls
(18), which are distributed uniformly over the circumference of the
calotte, are acted on by a pressing spring (22) each as a
tensioning element and engage correspondingly shaped and exactly
defined mounts (19) on the outer circumference of the ring collar
(15'). The spring force can be set by means of tightening screws
(21). The locking element (13) also forms the adjusting means (33)
at the same time for exactly positioning the safety device parts
(11, 12) during the first assembly and each time after the
deflection in case of a crash.
[0050] There is no locking element (13) in the two variants
according to FIGS. 7 and 8 as well as according to FIGS. 9 through
11. There is a frictionally engaged guiding here between the
calotte (14') and the spherical collar (15'). The frictional force
is generated by means of the clamping connection of the shell parts
(30, 31), which can be set correspondingly. In case of a
corresponding setting and tightening of the shell parts (30, 31),
such a frictionally engaged connection can also be obtained in the
first variant according to FIGS. 5 and 6.
[0051] Another adjusting means (33) is present in the embodiments
according to FIGS. 7 through 11. It comprises a plurality of
adjusting elements (34), especially adjusting screws, which
cooperate with corresponding mounts (35). One adjusting screw (34)
is arranged lying at the safety device part (11) in the area of the
calotte (14') and cooperates with a corresponding mounting opening
(35) at the ring-shaped collar (15') of the other safety device
part (12). The mounting opening (35) may be a blind hole according
to FIGS. 7 and 8. The rotated and pivoted position about the shaft
axis (38) and about the transverse axis through the center (40) can
be set by means of this.
[0052] In the variant according to FIGS. 9 through 11, the mounting
opening (35) is a slot (42), which extends along the axis (38) and
is open upwardly and downwardly toward the adjusting element (34).
Thanks to the slot (42), the safety device part (12) can rotate
with its ring-shaped collar (15') about the two axes indicated by
arrows in FIG. 11 in relation to the above adjusting element (34)
and deflect.
[0053] A second adjusting screw (34) is arranged in a projection
(39) of the safety device part (11) having a C-shaped cross section
in the design according to FIGS. 7 and 8. The projection (39)
extends over the shaft (37) at an axially spaced location. The
second adjusting screw (34) is preferably aligned flush with the
shaft axis (38) and engages a front-side mounting hole (35) at the
upper end of the shaft. The rotated position of the safety device
part (12) and of the shaft (37) about the longitudinal axis of the
first shaft screw (34) can be set by means of this second adjusting
screw (34). After the position has been found, the adjusting screws
(34) can again be screwed back in their threads at the safety
device part (11) and removed from the mounts (35).
[0054] The width of the spherical ring collar (15') and of the
calotte (14') can be set differently as needed and according to the
desired deflection behavior. The widths are preferably essentially
equal in the exemplary embodiments being shown, the calotte (14)
being able to be somewhat wider on both sides than the collar
(15'). The resistance during deflection is determined by the ratio
of the widths. The calotte (14') and the ring collar (15') may
become disengaged in some areas during deflection in case of a
small width, as a result of which the section modulus counteracting
the deflection is reduced. The consequence of this is a faster and
easier deflection, as a result of which deformations or other
damage to the device parts (6, 7, 8) due to overload can be
prevented from occurring.
[0055] A detector (24) is likewise present in the deflectable
safety device (10) according to FIGS. 5 through 11. It comprises a
contact switch or button, which is arranged in the projection (39)
of the safety device part (11) and is positioned eccentrically and
preferably in a direction obliquely to the shaft axis (38) in the
variant according to FIGS. 5 through 8. The switch cooperates with
a feeler (36) at the upper end of the shaft (37). Due to this
eccentric arrangement, the detector (24) responds in case of all
deflections about the center (40) and above all also during
rotation about the shaft axis (38). The feeler (36) loses contact
with the detector (24) during these deflections, and the detector
will then send a corresponding signal.
[0056] FIGS. 9 through 11 and especially the enlarged view in FIG.
11 illustrate a design variant of the detector (24). The feeler
(36) is designed in this case as a pressure piece (44), which is
guided longitudinally movably in an upper tube section (43) of the
shaft (37). The pressure piece (44) is acted on now on the rear
side by a spring (46) in the tube section (43), and the spring
force of this spring can be changed and set by an adjusting element
(not shown). The pressure piece (44) projects upward from the tube
section (43) with a rounded or conically shaped head part (45). The
head part (45) comes into positive-locking contact with a
complementarily shaped, conical or rounded mount (47). The mount
(47) may be designed, e.g., as a ring-shaped socket.
[0057] The detector (24) has a microswitch or sensor (48), which is
arranged in the projection (39) in the central axis (38) and comes
into switching contact with the tip of the head part (45). In case
of collision and deflection, the pressure piece (44) can yield
elastically and become separated from the socket (47), while the
microswitch (48) is actuated. The microswitch (48) may be of any
desired technical type and design and is also not limited to the
typical mechanical microswitches.
[0058] The microswitch (48) is guided movably along the axis (38)
in a housing opening (51) and is acted on from the underside with a
spring device (49), e.g., a compression spring, especially a plate
spring assembly. The spring device (49) is supported at a laterally
projecting collar of the microswitch (48). The microswitch (48) is
acted on from the top by a clamping cover (50) in an adjustable
manner against the force of the spring device (49). By actuating
the tightening screws, the clamping cover (50) can be moved up and
down along the axis (38). The detector (24) and the elastic
pressure piece (44) can thus be set exactly in relation to one
another. The microswitch (48) can then be closed in the determined
position and secured against undesired adjustment.
[0059] In this design, the detector (24) with its elastic pressure
piece (44) is part of the adjusting means (33) operating in a
positive-locking manner. This design has advantages in terms of
manufacturing technology and signal engineering. The sensitivity
with which the adjusting means (33) is triggered and also the
sensitivity of switching of the detector (24) can be set and
optimized by selecting the pretension of the spring. In addition,
the design effort is reduced compared with the other exemplary
embodiments.
[0060] The deflectable safety device (10) according to FIGS. 5
through 11 can also be used in conjunction with aligned device
parts (6, 7, 8) similar to the variants according to FIGS. 3 and 4
in case of a corresponding conversion. The safety device part (11)
has a correspondingly different shape in this case.
[0061] Various variants of the embodiments shown are possible. This
applies, on the one hand, to the arrangement and the positioning of
the deflectable safety devices (10) at the gripping device (1). The
gripping device (1) may have, besides, a different geometric design
and comprise other device parts (6, 7, 8). The frame (4) may be, in
particular, plate-shaped or have another solid design.
[0062] Furthermore, the design embodiments of the deflectable
safety device (10) and the parts (11, 12, 13) thereof may be
modified as well. For example, more than two safety device parts
(11, 12) may be present in intersections. The locking element (13)
may comprise, as an alternative, one or more geometrically defined,
stationary stops at the safety device parts (11, 12), against which
the respective other safety device part is pressed with a
predetermined force. The triggering force may be able to be set in
this case as well. In another variant, the locking element (13) may
have shearing pins, which engage corresponding mounts (19), instead
of one or more locking balls (18). The shearing pins consist of a
suitable material, which breaks at a defined overload and thus
makes possible a mutual deflection of the safety device parts (21,
22) while the positive-locking connection is abolished.
[0063] The design embodiment of the deflectable safety devices (10)
may, moreover, be selected to be completely different by using, for
example, electric buttons or sensors, which detect and report
overload forces when collisions occur, but deflection of a device
part (6, 7, 8) does not occur. Furthermore, it is possible to
operate with electric, pneumatic and hydraulic switch-off safety
devices, which function with or without deflecting movement.
* * * * *