Apparatus for gripping and weight-different clamping of workpieces, bar guides and the like to be held or moved relative to a location

An apparatus for gripping and weight-dependent clamping of workpieces, bar guides and the like that are to be held or moved relative to a location, particularly in connection with a hand-guided handling device that has a control switch. The apparatus includes a carrying frame to which are linked upper hinge-bolt pairs for respective superimposed pairs of parallel rods, which are detachably attached by pairs of lower hinge-bolts to a connection piece for gripping elements. A pair of struts, each of which is linked to one lower hinge-bolt, is jointly attached in articulated fashion to a control bolt centrally adjustable between the rods in a guide slot on the carrying frame.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an apparatus for gripping and weight-dependent 
clamping of workpieces, bar guides and the like that are to be held or 
moved relative to a location, in connection with a hand-guided handling 
device. 
2. Description of the Related Art 
The device mentioned above is known from German Gebrauchsmuster G 91 03 
520.1. The gripping elements mentioned in that document consist of 
semicircularly-curved gripping arms with a toggle lever system as well as 
circuit boards arranged centrally between the rods for controlling the 
movement of the gripping arms. However, the known device is designed as an 
incremental switch device, which allows intermediate off-loading as a 
switching stick is moved on a control cam and, in this way, the gripping 
arms are opened, closed, kept open or kept closed. The gripping arms can 
be kept open only in a certain position and according to a pre-established 
cycle. 
In order to grip disks, it is known to slip the required lifting hooks 
under a vertically-standing workpiece, e.g., a circular disk, from one 
side. When the lifting hook is raised, the workpiece rests upon two studs 
on the hook. However, lifting hooks of this type are ill-suited for use 
when disks of various sizes must be gripped or when disks must be 
processed in machine tools in two settings. After a disk has been removed 
by such a lifting hook following a first setting, it must then be set down 
and picked up again from the other side, because the lifting hook will 
always cover one side of the disk. Only after being turned in the machine 
tool can the workpiece be set up anew. 
During the use of conventional grippers that close automatically because of 
the load, problems arise in that the structural height of loaded 
grippers--and even that of unloaded grippers--is very great. This great 
structural height makes it difficult to operate a control switch located 
above the grippers while travelling over obstacles. It also reduces the 
possible stack height, compared to that possible with flatly-designed 
grippers. Furthermore, when subjected to a load, the gripping elements of 
conventional grippers always tend to close further, until they reach a 
maximum position. If it is impossible for them to reach this position, due 
to workpiece geometry, then those workpieces without form-stability 
undergo additional extensive secondary bending. In the case of plastic 
containers, this secondary bending quickly leads to damage at the grip 
points. It is also disadvantageous that loads arranged movably in 
containers may tend to tilt and may thus fall out. Furthermore, many 
inner-gripping grippers extend over the container edge, so that these 
containers cannot be stacked close together. Finally, it is 
disadvantageous that the known gripper elements lack suitable centering 
elements that would permit quick placement of the grippers on the 
containers or, when grippers are lifted off containers at a slant, would 
prevent gripper parts from getting caught on the container. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a device 
for gripping and weight dependent clamping so that, while eliminating the 
described disadvantages, it is unnecessary for workpieces of various sizes 
to be set down and picked up again between two settings when there is only 
limited lateral free space. It is a further object to create a compact 
device which permits the gripper elements to be adjusted to workpieces of 
various shapes and types. In addition, it is to be possible to fix the 
gripping arms in place over the entire lifting area in order to avoid 
injuries while manipulating the gripping arms by hand. 
Pursuant to these objects, and others which will become apparent hereafter, 
one aspect of the present invention resides in a device as described above 
having a carrying frame, to which upper hinge-bolt pairs for respective 
superimposed pairs of parallel rods are linked. The rods are detachably 
linked by pairs of lower hinge-bolts to a connection piece for gripping 
elements. A pair of struts, each respective strut of which is linked to 
one lower hinge-bolt, is jointly attached in articulated fashion to a 
control bolt, which is centrally adjustable between the rods in a guide 
slot on the carrying frame. Such a basic module permits the use of 
internal-gripping and external-gripping parts for a wide variety of 
workpiece shapes and types. The device can thus be adjusted to the 
particular material to be conveyed. 
In addition, special advantages of the basic module include very high 
levels of work safety and operating convenience as well as a compact 
design with relatively great lift. It is always possible to open the 
device by placing it on material to be conveyed and to keep the device 
open in any desired position, after removal of a set-down workpiece, by 
operating an operating element. This eliminates a significant risk of 
injury that exists when known shear grippers are used. The standard shear 
grippers lock into place only in the completely open position and must 
sometimes be manipulated by hand, even for the purpose of opening closed 
grippers or keeping the grippers open in an intermediate position. The 
small structural height of the device according to the invention, compared 
to known shear grippers, as well as its compact lateral dimensions, reduce 
the "dead measure" of the handling device, make it easier to operate the 
control switch while travelling over obstacles, and permit handling under 
cramped conditions in the machine free space, in containers and with 
densely stacked material to be conveyed. 
According to a further embodiment of the invention, outside of the carrying 
frame there is a quick-change mechanism with a coupling neck, which can be 
coupled into a receptacle of a control switch. A quick-change mechanism of 
this type has the advantage of creating a connection to a hand-held 
handling device that has a control switch, so that the gripping device can 
be guided and operated in a controlled manner. 
In another embodiment of the invention, a handle with an operating lever is 
attached to the carrying frame. As a result, the device can be handled and 
controlled with one hand. 
In still another embodiment of the invention, the distance between the 
gripping elements in their end positions can be established by means of 
the length and position of the guide slot. The difference between the 
maximum and the minimum distance of the gripping elements to one another 
constitutes the lift of the gripping device. The half-lift is the lift per 
gripping element. When travelling through the lift, the gripping elements 
always remain parallel to one another. 
In a further embodiment of the invention, the control means arranged 
centrally between the rods is a locking mechanism. In contrast to the 
prior art, the invention therefore does not use an incremental switch 
device, but rather a locking mechanism. Furthermore, an advantage of the 
invention is that the control bolt can be set by means of the locking 
mechanism into a plurality of positions. For this purpose, a suitable 
clamping mechanism can be blocked or locked in a positive-locking manner 
in a very fine grid. 
In detail, the invention calls for the following measures: The control bolt 
is connected to the block so as to permit a slight crosswise movement of 
the block. The block is provided on the outside with fine toothing in the 
direction of the guide slot, and similar toothing, running parallel to the 
toothing on the block, is provided on a rod attached to the carrying 
frame. The plurality of positions of the locking mechanism can thus be 
influenced by the number of teeth in the toothing. 
According to other features of the invention, the block to hold the control 
bolt itself forms a guide slot, which is vertical or crosswise relative to 
the course of the guide slot. The distance travelled by the block on the 
control bolt is then slightly greater than the meshing area of the teeth, 
in order to permit clicking-in and clicking-out. 
Furthermore, spring-mounted clamping bolts are arranged in pairs in the 
block at a right angle to the course of the guide slot, in order to 
decouple the block from the toothing. 
In an advantageous embodiment, a level glide surface is arranged on the rod 
parallel to the toothing so that the glide surface constitutes a guide. 
In a further embodiment of the invention, a saddle-type part is arranged on 
the carrying frame in a longitudinally movable fashion and is connected to 
a leg. The leg has slots which run obliquely upward, and through which 
guide bolts that are attached to the carrying frame run. When the 
saddle-type part is lifted up from the carrying frame, the slanted 
position of these slots causes the leg to move the block with 
toothing--against the force of the spring-mounted clamping bolts and 
independent of the position of the control bolt--into engagement with the 
toothed rod. 
Other features of the invention provide that when no load is present, the 
saddle-like part and the legs unlock the control bolt by means of tension 
springs arranged in pairs. The tension springs ensure that when the device 
is not subjected to any load, the saddle-like part is always drawn into 
the position in which the control bolt is unlocked. 
According to another feature of the invention, the path of the saddle-like 
part is limited by means of carrying screws. These turn-proof carrying 
screws constitute the displacement path and the power transmission from 
the carrying frame via the saddle-like part onto the coupling neck to the 
handling device. 
In another embodiment, the locking mechanism can be manually activated by 
means of a handle and an operating lever. This occurs as follows: The 
operating lever is swingably mounted around a rotational axis on the 
carrying frame and has a take-along pin, which runs via a slot in a 
slider, which is also movably mounted on the carrying frame, via slots 
running obliquely upward. This permits the device to be operated and 
controlled with one hand and, as needed, the locking mechanism to be 
activated not only by means of a load, but also by hand. 
The required functions are achieved by virtue of the fact that the slider 
is run in a movable fashion relative to the carrying frame, by means of 
the bolts. 
In order to prevent the device from opening during inadvertent impact with 
the load or if the device is set down during transport, a leaf spring is 
attached to the saddle-type part, which rests by a heel on the operating 
lever. 
The set position is secured as follows by an external lever arm of the 
operating lever that can be arrested by means of a spring-mounted sphere 
on the rod. 
Advantageously, the workpieces are gripped, according to the type of 
workpiece, by gripping elements that are provided either with a rigid 
gripping prism or with a self-adjusting gripping prism. 
A related embodiment has proved outstanding in this respect, because the 
self-adjusting gripping prism has an external part with a load support 
attached at the end and a hold-down appliance, located approximately 
opposite to the load support, with a holding means, whereby the holding 
means is run movably on the bars and accommodates the hold-down appliance 
by means of studs arranged in bores. The contact surface can be formed so 
that the hold-down device is adjusted over the entire lift of the 
particular gripped workpiece. 
Furthermore, an external part has a glide foot, which is equipped with a 
anti-slip cover and a separate shoulder for quick opening upon lowering. 
This provides the glide foot with a great advantage, namely, that even 
workpieces stacked relatively close together can be gripped without first 
being separated manually. 
The lifting capacity of the device can be increased by equipping an 
external part with an auxiliary load support, which has a holding 
protrusion directed toward the workpiece. 
Heavier workpieces often have asymmetrical load distribution. In addition, 
in some cases, there are sharp diameter discontinuities on the workpieces. 
For disk-shaped workpieces it is especially advantageous that a gripper 
element consists of a gripper arm, on which a clamping prism is mounted in 
a spring-mounted and back-swingable fashion around a bolt at the end of 
the gripping arm. 
Picking up special workpieces that are stacked or located next to one 
another often entails specific considerations. For workpieces arranged in 
this manner, each gripping element has an external spline boring located 
opposite to the hinge-bolt. An external spline runs in each external 
spline boring, and a support jaw and/or at least one lifting hook are 
arranged on the external spline. Support jaws and lifting hooks are thus 
easily exchangeable and can be shaped or designed accordingly. 
In this respect, it is also advantageous that the gripping elements for 
closely stacked workpieces consist of a lifting hook with an angled arm 
and are mounted pivotally on the external spline, while means to limit the 
swinging movement and means to prevent an axial movement are provided. For 
example, the angled arm can be placed on the perimeter of a support jaw, 
and the means for limiting the swinging movement can consist of pins and 
the like. 
It is also possible to utilize the lift of the "basic module" in a limited 
fashion. To this end, the gripping elements consist of gripping strips 
adjustable relative to one another on a plane, both of which are connected 
to the connection pieces via hinge-bolts and accommodate a centering 
frame. The device in this form is especially suitable for containers with 
gripping areas into which the device engages. 
In order to ensure that workpieces of the container type are gripped 
evenly, centering levers are pivotally mounted on the respective end areas 
of the centering frame and are secured against axial movement. 
In order to allow universal use of the device and also to permit the device 
to be used in the form of a folding undercarriage, a roller holder with 
rotatably mounted running rollers is attached to the connection pieces. 
The device can then be used in reverse of its normal position, in the area 
of bar guides and the like. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of the disclosure. For a better understanding of the invention, its 
operating advantages, and specific objects attained by its use, reference 
should be had to the drawing and descriptive matter in which there are 
illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, the apparatus for the gripping and weight-dependent clamping of 
workpieces is shown in connection with a hand-guided handling device, 
which has a control switch 1, which is connected via a quick-change 
mechanism 2 to a coupling neck 2a in a receptacle 1a. The control switch 1 
of the handling device can be connected to the handling device via a rigid 
guide, a chain, a cable or the like, and signal lines. However, the device 
can also be connected directly to a carrying system (traction means) of 
the handling device, and the control switch 1. can be arranged separately. 
The arrangement shown in FIG. 1 is advantageous because it is possible to 
operate the handling device and the inventive apparatus and to guide a 
load quickly and safely with one hand. The other hand of the operator is 
free to carry out other activities. 
The inventive apparatus includes a handle 3 as an operating element with an 
operating lever 3a, which can be swung around a rotational axis 3b (FIG. 
3). 
The apparatus (FIGS. 1 to 5) is basically comprised of a basic module, 
which consists of the aforementioned handle 3 as the operating element, a 
locking mechanism 12, and a lever system for any desired mountable and 
quickly exchangeable gripping elements 7a. 
This so-called basic module has adjacent pairs of parallel rods 4, which 
are attached by means of upper hinge-bolt pairs 5a, 5b to a carrying frame 
8. The parallel rods 4 are detachably attached by pairs of lower 
hinge-bolts 6a, 6b to a connection piece 7 for the aforementioned gripping 
elements 7a, and a pair of struts 10. Each strut is attached to one lower 
hinge-bolt 6a or 6b and is jointly connected in articulated fashion to a 
control bolt 9 that is centrally adjustable between the rods 4 in a guide 
slot 8a of the carrying frame 8. In a sense, the lower hinge-bolts 6a, 6b 
represent an interface between the so-called basic module and the gripping 
elements 7a. The path travelled by the control bolt 9 also determines the 
particular distance between the gripping elements 7a, so it is possible to 
determine the spacing of the gripping elements 7a relative to one another 
in their end positions by means of the length and position of guide slot 
8a. 
According to FIG. 1, the control bolt 9 is located at its lower end stop. 
Thus, the gripping elements 7a also assume t heir lowest position and are 
therefore located at their minimum distance from one another. In contrast, 
the upper end of the guide slot 8a limits the maximum distance of the 
gripping elements 7a. As this happens, the distance between the gripping 
elements 7a and the carrying fra me 8 is also reduced. The difference 
between the maximum and the minimum distance of the gripping elements 7a 
(or of the lower hinge-bolts 6a and 6b) relative to one another 
constitutes the lift of the device. The half-lift of the device is thus 
created per gripping element 7a. 
When travelling through this lift, the position of the gripping elements 7a 
relative to one another always remains parallel. In the event that the 
control bolt 9 becomes blocked in an intermediate position in the guide 
slot 8a, the two gripping elements 7a are also fixed in place in a certain 
position. However, universal applicability of the device is achieved when 
the gripping elements 7a can be fixed in placed not only in one particular 
position, but in a plurality of positions, whereby the control bolt 9 can 
be arrested by means of t h e locking mechanism 12 in this plurality of 
positions. 
In FIG. 2, the locking mechanism 12 is shown in greater detail. The control 
bolt 9 extends into a block 11 with a crosswise guide slot 11a. A pin 12a 
of the locking mechanism 12 connects the block 11 in this direction with 
the control bolt 9 so that the block 11 cannot move axially relative to 
the control bolt 9, but can move relative to the control bolt 9 at a right 
angle to the guide slot 8a of the carrying frame 8. Parallel to the guide 
slot 8a, and extending over the entire path travelled by the control bolt 
9 in the guide slot 8a of the carrying frame 8, there is a bar 13, which 
ha s teeth 13b corresponding to teeth 11b on the block 11. The ba r 13 is 
positioned so that when the block 11 moves toward the toothed bar 13 with 
the mating-teeth 13b, the teeth 11b on block 11 engage with the toothed 
bar 13. The distance travelled by the block 11 on the control bolt 9 is 
slightly greater than the meshing area of the teeth. In the toothed block 
11, there are also spring-mounted clamping bolts 14, which press the block 
11 away from the toothed bar 13. For this purpose, a level glide surface 
13a is provided on the bar 13 in front of the teeth 13b. The engagement of 
the teeth 11b and 13b is carried out via a saddle-like part 15, which is 
arranged movably on the carrying frame 8. 
The saddle-like part 15 has a leg 15a with obliquely arranged slots 15b. 
The slots 15b guide the saddle-like part 15 via bolts 16, which are firmly 
attached to the carrying frame 8. When the saddle-like part 15 is lifted 
up from the carrying frame 8, the slanted position of the slots 15b causes 
the leg 15a to bring the toothed block 11 into engagement with the toothed 
bar 13, against the force of the spring-mounted clamping bolt 14, 
regardless of the position of the control bolt 9. Furthermore, when the 
apparatus is not subjected to any load, tension springs 17 cause the 
saddle-like part 15 to always be drawn into the position in which the 
control bolt 9 is unlocked. 
The coupling neck 2a, as shown in FIG. 1, is attached securely to the top 
side of the saddle-like part 15. In the event that the saddle-like part 15 
is lifted up from the carrying frame 8, against the force of the tension 
springs 17, turn-proof carrying screws 18 (FIG. 1) limit the distance 
travelled and establish a transmission of power from the carrying frame 8 
via the saddle-like part 15 onto the coupling neck 2a to the handling 
device or its control switch 1. The power relationships of the rods 4 
arranged in the form of a parallelogram are designed so that the apparatus 
is self-closing, even without a locking mechanism 12, when prismatic-type 
gripping elements 7a are used. The weight of the goods to be conveyed, 
which acts centrally on the gripping elements 7a, causes the apparatus to 
close. Loads gripped outside of their center of gravity, e.g., shafts, act 
(beginning with a certain asymmetry) on the apparatus in a levering 
manner. To ensure that the apparatus then does not open unintentionally, 
the locking mechanism 12 is activated. However, the locking mechanism 12 
is also used in order to prevent the opened apparatus from closing again 
when a load is set down. In this situation, the lock is activated via the 
handle 3 and the operating lever 3a. In FIG. 3, the operating lever 3a is 
swingably attached to the carrying frame 8 by the rotational axis 3b and 
has a take-along pin 3c on an outer lever arm 3d. The take-along pin 3c 
extends into a slot 19a of a slider 19. The slider 19 is comparable to the 
saddle-like part 15 that runs movably on the bolts 16. The slider 19 has 
slots 19b arranged at a slant, similar to those of the leg 15a. In the 
position shown in FIG. 3, the slider 19 brings the toothed block 11 into 
engagement with the toothed bar 13 and prevents the empty apparatus from 
closing. To release this lock, the handle 3 is swung in the direction of 
the control switch 1, so that the slider 19 is brought into a congruent 
position with the leg 15a. As a result, the block 11 again reaches the 
position shown in FIG. 2, the apparatus finds itself in the unlocked 
position, and the gripping elements 7a close. 
A further function of the locking mechanism 12 is to prevent the apparatus 
from opening during transport if there is an unintentional impact on the 
load or if the load is set down. This function is shown in FIGS. 4, 3a, 5 
and 5a. A leaf spring 20 with a heel 20a is attached to the saddle-like 
part 15 so that the heel 20a extends under the outer lever arm 3d. If, 
when the load is picked up by the apparatus (as shown in FIGS. 4 and 4a), 
the saddle-like part 15 is lifted up from the carrying frame 8, then the 
operating lever 3a is also swung up above the heel 20a. In this position, 
a sphere 21 is pressed by a spring (not shown) arranged in the back into a 
bore 3e of the outer lever arm 3d and, as a result, arrests the outer 
lever arm 3d. In this position, the block 11 is pressed by both the leg 
15a and the slider 19 toward the toothed bar 13. In the event that while 
the apparatus is being handled, the gripped workpiece or the gripping 
elements 7a are unintentionally placed on an obstacle, the saddle-like 
part 15 again moves into the position shown in FIG. 2. The leaf spring 20 
is thereby pushed downward, while the operating lever 3a, remains in its 
arrested position over the sphere 21. As a result, the apparatus is not 
able to open and the workpiece cannot be lost. In the event that the 
workpiece, in another case, is intentionally set down, the operator is 
able, using slight manual force, to swing the handle 3 in the direction of 
the control switch 1 against the resistance of the sphere 21, in order to 
open the apparatus. It is also possible, however, to release the arrest of 
the operating lever 3a when the load is still suspended in the apparatus 
and the grippers have not yet been put down. This case is shown in FIG. 5. 
The apparatus then does not open until it is next put down. The operating 
lever 3a is hereby swung downward against the resistance of the leaf 
springs 20 from the heel 20a. Releasing the arrest in this fashion while a 
load is still suspended permits the operator to put down and open the 
apparatus without an intermediate stop. However, the release of the 
apparatus while the load is still suspended can also be rescinded at any 
time by activating the operating lever 3a. The apparatus then remains 
locked until the operator deliberately activates the handle 3, with a 
suspended load or a set-down load. Each function of the apparatus is 
immediately available, without a fixed cycle having to be followed. 
In some applications, however, it may not be possible to release the lock 
while the load is still suspended. In these cases, the leaf springs 20 are 
replaced by a rigid take-along means which, like the heel 20a, grip under 
the operating lever 3a. However, the operating lever 3a can then no longer 
be used when the saddle-like part 15 is lifted up. 
The gripping elements 7a are exchangeable at the interface (lower 
hinge-bolts 6a, 6b) on the so-called basic module. In contrast to the 
gripping element 7a with a rigid gripping prism 22 shown in FIG. 6, the 
embodiments in FIG. 7 and 7a show a gripping element with a self-adjusting 
adjustment prism. For the sake of better comparison, the depths "t" of the 
gripping prism 22 are identical. However, the effective areas of 
congruence between the gripping prism 22 and the indicated workpieces 27 
and 28, "h1" and "h2", are smaller than "t". But the subject-matter shown 
in FIGS. 7 and 7a presupposes the amount "t" as the effective congruence. 
For this reason, the angular deviations .beta.1 and .beta.2 between the 
active lines of the weights of the workpieces 27 and 28 and the support 
forces on the gripping prism 22 are always smaller than the angular 
deviations .alpha.1 and .alpha.2 as in FIG. 6. As a result, using an 
adjustable gripping prism 22 with the same workpiece weight, lesser 
support forces are required; or, when the load capacity of the gripping 
prisms 22 is equal, higher workpiece weights are permissible than with the 
rigid gripping prism 22. A further advantage of the self-adjusting 
gripping prism 22 is that the gripping elements 7a for small workpieces do 
not extend out so far under the workpiece. The workpieces 27, 28 can thus 
also be handled even when there is less ground clearance. 
The adjustable gripping prism 22 consists of an outer part 23 of a load 
support 24, a hold-down appliance 25, and holders 26. The holders 26 are 
run movably on the rods 4 and accommodate the hold-down appliance 25 on 
studs 25a in bores 26a in swingable fashion. In addition, the hold-down 
appliance 25 is run on the load support 24 so that the hold-down appliance 
25 is always in contact with a contact area 23a and is adjusted over the 
entire lift to the diameter of a workpiece 27, 28, which lies on the 
contact area 23a. Because the basic module automatically locks the 
apparatus when a load is picked up, the hold-down appliance 25 is able to 
support itself directly via the studs 25a under the rods 4 when the 
workpieces 27, 28 tilt, without the apparatus opening. 
To safely manipulate the workpieces 27, 28, it is sufficient for the 
apparatus to be equipped with only one adjustable gripping prism 22. On 
the second side, the outer part 23 is combined with a glide foot 29. The 
glide foot 29 has an anti-slip cover 29a to prevent axial movement of the 
workpieces 27, 28 as well as a shoulder 29b for quicker opening of the 
apparatus when it is lowered onto the workpiece 27, 28. However, in the 
case of heavy workpieces, it is also possible to replace the glide foot 29 
with an auxiliary load support 30, as shown in FIG. 8. In this way, the 
permissible carrying load of the apparatus is doubled, compared to the 
embodiment with a glide foot 29. In addition, heavier workpieces 27, 28 
also frequently have an asymmetrical load distribution. Considerable 
diameter discontinuities are experienced, as shown in FIG. 9. With 
conventional grippers, it is often possible to grip such workpieces 27, 28 
only in a very disadvantageous manner. This occurs particularly when a 
shaft-workpiece must be placed in a tooling machine or when, in order to 
avoid axial slippage, suspension in the apparatus must be as horizontal as 
possible. For this reason, a load support 31 and the auxiliary load 
support 30 have external spline bores 31a, 30b with external splines. 
These external spline bores 31a, 30b serve to accommodate corresponding 
external splines 32. At the free end of the external splines 32, as 
needed, additional supporting jaws 33 can be positioned in such a manner 
that the asymmetrical workpiece 27, 28 rests at the desired positions. 
Because the points needed for support of a workpiece 27, 28 can also have 
different diameters, the supporting jaws 33 are staggered in keeping with 
the tooth spacing as in FIG. 8a, or are slipped onto the external spline 
32 in mirrored and staggered fashion in FIG. 8b. Because of the fixed 
tooth spacing, it is possible to adjust to certain diameter steps. When 
the mirrored arrangement is used, particular intermediate steps can be 
adjusted to. In this way, the total step discontinuities are halved. The 
external splines 32, however, can also be exchanged as needed for any 
desired workpiece-specific supporting levers. Fixing the splines 32 in 
place against axial slippage in the spline bores 31a, 30b, as well as 
fixing the supporting jaws 33 in place on the splines 32, is carried out 
by means of clamping screws 34, as shown in FIG. 8b. 
A further alternative for handling shaft-type workpieces 27, 28 is shown in 
FIG. 8c. Workpieces of this type 27, 28 are frequently stacked very close 
together on workpiece carriers. In such cases, it is difficult to slip a 
gripper between two adjacent shafts. Especially in the case of long heavy 
workpieces 27, 28, separating the workpieces prior to gripping and putting 
them close together again after they have been set down is very difficult 
and time-consuming. For this reason, the embodiment shown in FIG. 8c 
contains a lifting hook 53, which is mounted rotatably by a receptacle 
bore 53a on the external spline 32. An angled arm 53b of the lifting hook 
53 rests on the supporting jaw 33. The lifting hook 53 grips under the 
workpiece 27 or 28. When the apparatus is closed, the two external splines 
32 move toward one another. The smaller the distance between them, the 
more the lifting hook 53 is swung up via the angled arm 53b. In the 
position shown of the supporting jaw 33, the workpiece 27, 28, i.e., a 
shaft 54, is clamped between the lifting hook 53 and the supporting jaw 
33. As the size of distance "a" increases, the swinging distance of the 
lifting hook 53 increases as well, and the lifting hook 53 swings up when 
the apparatus is closed. When the device is in the completely open 
position (not shown), the distance relative to "a" is even greater, in 
relationship to the radius "R" in the opposite direction. Thus the lifting 
hook 53 swings away from the workpiece 27, 28. For safe handling, the 
lifting hooks 53 are used in pairs. The distance of the two lifting hooks 
53 to the external spline 32 is freely selectable. 
According to FIG. 8d, an adjustment ring 55 is provided, which secures the 
lifting hook 53 against axial slippage on the external spline 32 and at 
the same time limits the swinging range of the lifting hook 53. For this 
purpose, the adjustment ring 55 has the same receptacle bore 55a with an 
external spline profile as the supporting jaw 33. Fixing the adjustment 
ring 55 in place on the external spline 32 is also carried out by means of 
a clamping screw 34. In addition, the adjustment ring 55 has two 
arc-shaped slots 55b. Pins 56 are run through the slots 55b, the heads of 
which lie in front of the adjustment ring 55, which are securely placed in 
bores 53c of the lifting hook 53. By moving the adjustment ring 55 on the 
external spline 32, it is now possible to enlarge or reduce the size of 
the swinging range of the lifting hook 53. In the event that the angled 
arm 53b of the lifting hook 53 is on the same plane as the lower, curved 
part, then the swinging range is limited, as shown in FIG. 8d, so that 
when the apparatus is opened the lifting hook 53 does not get tangled up 
with the supporting jaw 33. However, the lifting hook 53 can also be 
designed so that the angled arm 53b is set back toward the rear, relative 
to the lower part of the lifting hook 53. In this case, the lifting hook 
53, with a somewhat shortened external spline 32, can be positioned on the 
left-hand side in such a way that the lower part of the lifting hook 53, 
when swung up, is able to swing past in front of the external spline 32 
(left-hand side) and the supporting jaw 33. 
This situation is shown in FIG. 8e. The swinging range changes accordingly. 
The adjustment ring 55 prevents the lifting hook 53 from tilting to the 
rear. A folding-up of the lifting hook 53 occurs in this manner when a 
workpiece 27, 28, i.e., a shaft 54, is picked up quite normally with the 
first load surface 31 and the other load surface 30. Such a procedure is 
conceivable when a workpiece 27, 28 is gripped by the lifting hook 53 as a 
rough piece and lifted, for example, into a tooling machine, but later, as 
a finished part, forms a sharply shouldered shaft 54. In this case, 
additional supporting jaws 33 are positioned as desired on the external 
splines 32. After the sharply shouldered shaft 54 is set down, the lifting 
hooks 53 are used to push the parts together on the workpiece carrier. 
Instead of an external spline bore 31 a with an external spline 32, other 
profiles securing against turning or, for stepless setting, round rods 
with suitable clamping mechanisms can be used. With the described gripping 
elements 7a, all parts that come into contact with the gripped workpiece 
27, 28 or 54 are quickly exchangeable as parts subject to wear. The 
materials used in these parts are selected so that even workpieces 27, 28 
or shafts 54 with a high surface quality are not damaged during handling. 
The described gripping elements 7a can also be used in a modified form, 
e.g., when extremely short workpieces 27, 28 or shafts 54, disks, rolls or 
wheels are to be handled. 
As further alternatives for disk-shaped workpieces, gripping elements 35 as 
shown in FIGS. 10 and 11 are provided. The clamping prism 37 is mounted on 
the gripping element 35 so as to be swingable around bolt 36. The clamping 
prism 37 encompasses the gripping element 35 in a U-shaped fashion. A 
tension spring 38 is attached to the gripping element 35 and to the 
clamping prism 37 in such a manner that the clamping prism 37 is always 
swung into a position of congruence with the gripping element 35. In this 
swung position, spring-mounted balls 39 in the clamping prism 37 click 
into corresponding bores 35a in the gripping element 35. This catching 
mechanism and the tension spring 38 ensure that the clamping prism 37 
swings in the direction of the glide foot 29 only after there is a certain 
load on the tip 37a of the clamping prism 37. The load threshold is 
designed so that the clamping prism 37 swings only after the locking 
mechanism in the basic module as per FIG. 3 has fixed the gripping 
elements 35 in place. During swinging, a workpiece 27, 28 or a disk-shaped 
workpiece 27; 28 located between the gripping elements moves, at a 
maximum, by the amount "s" toward the glide foot 29 and therefore sinks 
downward by the amount "I". Because the load always lies outside of the 
rotational axis on the tip 37a of the clamping prism 37, the contact 
surface 37b is also pressed at the same time toward the workpiece 27, 28 
or the shaft 54. As a result, the gripping elements 35 always lie securely 
at three points on the workpiece 27, 28 or the shaft 54 and prevent 
tilting in the case of disk-shaped workpieces. When the workpiece 27, 28, 
54 is set down, the tension spring 38 always brings the clamping prism 37 
back to the arrested initial position. The large lift of the rods 4 in the 
so-called basic module here results only in the setting of the gripping 
elements to many different workpiece sizes, and the clamping of the 
workpieces 27, 28 and 54 is achieved by means of the swingable clamping 
prism 37. 
As shown in FIG. 11, the gripping elements 35 are very narrow when seen 
from the side, so that even the workpieces 27, 28, which consist of narrow 
disks, remain accessible from both sides. The gripping principle is 
similarly applicable to shafts 54. The shafts 54 are thereby secured 
against axial slippage. 
In the case of shafts 54 or disk-shaped workpieces 27, 28, the gripping 
elements 7a, 35 are always pushed from the outside over the workpiece in 
question. However, there are also many applications where workpieces 27, 
28 must be gripped from the inside, in an interior bore or any desired 
opening. These cases occur, for example, in the handling of plastic 
containers. 
An example for such a case is described in FIGS. 12 to 14. The rods 4 
accommodate at their lower hinge-bolts 6a, 6b, gripping strips 41, 42 in 
receptacle bores 41a, 42a. The gripping strips 41, 42 are arranged in 
mirrored and overlapping fashion. In addition, for guidance, the gripping 
strips 41, 42 have slots 41b, 42b in which the lower hinge-bolts 6a, 6b 
located respectively across from the receptacle bores are arranged. The 
distance of these slots 41b, 42b to the bores 41a, 42a determines which of 
the lift ranges of the basic module will be used. The length of these 
slots 41b, 42b can be used to limit the lift of the gripping strips 41, 
42. When the apparatus is adjusted to a certain workpiece 27, 28, e.g., a 
certain container, it is not advantageous to utilize the entire large lift 
of the basic module. The greater this lift is, the greater also is the 
structural height of the device with the gripped workpiece 27, 28. The 
gripping strips 41, 42 are also provided with slots 41c, 42c. These slots 
are arranged in such a manner and are of such a size that when the two 
slots 41c, 42c overlap in the final positions of the gripping strips, a 
bolt 43 inserted through both slots is always positioned centrally between 
the hinge-bolts 6a, 6b. The bolt 43 extends further through a bore 43a of 
a centering frame 44. In the final positions of the gripping strips, the 
centering frame 44 is thus always centrally aligned. The centering frame 
44 also has an elevation 43b on its respective ends. The elevation 44b 
becomes thicker toward the rear, lies on the gripping strips and extends 
past the latter to the rear. The elevations 44b are provided with bores to 
accommodate screws 45. Centering levers 46 are mounted swingably and 
secured against axial movement on these screws 45, in the rear, at the 
free end. 
The swinging range of the centering levers 46 is limited upwardly by a 
bracket 47 attached to each gripping element 7a and by a ball thrust screw 
48, and is limited downwardly by a stud 49a attached to the gripping strip 
by a screw 49. The stud 49a extends thereby below the centering levers 46. 
As shown in FIGS. 13 and 14, the centering levers 46 have angular contact 
elements 46a on the free ends. The gripping strips 41, 42 are also 
provided at the free ends with singular grip pieces 41d, 42d. 
When the apparatus is open, as in FIG. 14, the gripping strips 41, 42 are 
always pushed toward the center of the apparatus, relative to the 
centering levers 46. When the apparatus is lowered onto a container edge, 
it is centered relative to the container in the longitudinal direction. As 
this is done, the grip pieces 41d, 42d are passed over the container edge 
without hitting it, via the angular contact elements 46a of the swingable 
centering levers 46. The apparatus is lowered until the contact elements 
46a lie on top of the container edge and the centering levers 46 rest 
under the ball thrust screws 48. In this state, the gripping elements 7a 
also dip into the container. In the case of stacked containers, the smooth 
lower edge of the gripping strips 41, 42 also serves here to control the 
loading height. In the event that the operating lever 3a on the basic 
module is swung in the direction of the apparatus center, the gripping 
strips 41, 42 initially move, when the apparatus is subsequently lifted 
up, only horizontally to the outside. Advantageously, on the back side of 
the apparatus, another, second pair of gripping strips can be arranged as 
described. In this case, the angular grip pieces 41d, 42d, which are thus 
also present in pairs, form a broad support surface, which extends under 
suitable gripping or holding means of the container. These support 
surfaces can be narrowed toward the outside. If this is done, then the 
apparatus also laterally centers itself when the gripping strips 41, 42 
are moved apart via the narrowing of the support surfaces in the holding 
or gripping elements of the container. The gripping elements 7a or the 
gripping strips 41, 42 are not lifted up until they have been moved so far 
that the vertical legs of the angular grip pieces 41d, 42d lie on the 
container handle from the inside. In this phase, the horizontal legs of 
the grip pieces 41d, 42 lie under the container handles and lift these up. 
When the load is picked up, the gripping strips 41, 42 are fixed in place 
by the basic module; the container handles cannot be pushed apart then, 
even in the case of heavy loads. In this state, the container handles are 
surrounded on three sides by the angular grip pieces 41d, 42d and the 
angular contact elements. The distance of the grip pieces 41d, 42d, which 
are arranged in pairs, is adjusted to the width of the container handle. 
As a result, it is not possible for the container to shift or fall, even 
when there are movable contents. The grip pieces 41d, 42d and the 
centering levers 46 do not extend over the container edge. The centering 
levers 46 prevent the grip pieces 41d, 42d from remaining caught below the 
container handles when the opened apparatus is lifted up. 
A further alternative of the device is shown in FIG. 15. In this example, 
the gripping elements 7a are represented by roller holders 50 and running 
rollers 51. This example indicates that the device can be used as a 
folding undercarriage. The great lift of the device permits combination 
with different profiles, i.e., bar cross-sections. It is especially 
advantageous that the running rollers 51, located opposite one another, 
adjust to the bar width. This effect permits the use of running rollers 51 
with a guideway band 51a. In this design, additional rollers for lateral 
guidance are not necessary. The middle web of the bar profile thus remains 
free and can also be equipped with additional ribbing, or installation 
conduits can be laid in the interior space. As required, the running 
rollers 51 can also be arranged in pairs, for example, one behind the 
other. Height-adjustable stops 52 prevent disproportionate tilting in the 
case of skewed traction. 
Instead of the coupling neck 2a (cf. FIG. 1), a lifting hook 53 is provided 
here. In the event that the undercarriage is combined, for example, with a 
pulley block, it is possible during assembly work to quickly establish a 
transport segment with the functions of lifting or lowering and moving on 
the horizontal. 
The invention is not limited by the embodiments described above which are 
presented as examples only but can be modified in various ways within the 
scope of protection defined by the appended patent claims.