DE29609891U1 - Device for manual lifting / lowering and positioning of loads - Google Patents

Description

Applicant:

Dr. Suhr + Partner GmbH
Pforzheimer Strasse 377

70499 Stuttgart

4145 001 W/sch 05.06.1996

Title: Device for manual lifting/lowering and positioning of loads

DESCRIPTION

The invention relates to a device for manually lifting/lowering and positioning loads, in particular for loading and unloading workpieces on machines, with a horizontally movable swivel arm, at one end of which a holder for the load provided with an operating element is provided, and the other end of which is attached to a lifting device.

When loading machine tools and production machines with devices and workpieces, weights of more than 20 kg often have to be handled. This is especially true when fitting clamping systems, for example in machine tools. The clamping systems include, for example, cast pallets with a hole pattern and a holding device

on the underside. They can have a load capacity of 100 kg and more and have a not inconsiderable weight. The fitting into the machine must be very precise; the tolerances are in the range of less than 1 millimeter. In individual and small series production, however, there is usually no special device for this work for reasons of flexibility and costs. For larger weights, loading is therefore usually done from above using slewing cranes, overhead cranes or from the side using forklifts. This type of loading has significant disadvantages. When loading with crane systems, the loads swing, which can lead to collisions between the workpiece and the machine. Increasingly, loading from above is no longer possible with modern machine tools because the work area is not freely accessible due to the full enclosure. Loading from the side is relatively difficult with the usual weight of these loads because they are too heavy to handle without mechanical support. When loading with a forklift or pallet truck, a minimum aisle width is required in front of the machine in order to have enough maneuvering space for moving the workpieces into the correct position. In addition, with this type of loading it is almost impossible to set down the workpieces in the correct position. Moving to a specific position with millimeter precision and simultaneously specifying a fixed rotational alignment of the workpiece cannot be achieved with the usual rigid gripper fork systems on lifting vehicles.

In particular, changing workpieces and fixtures into fixed holders requires pre-positioning within a tolerance range of fractions of a millimeter in order to guarantee safe entry into the change position and to avoid the risk of damage to the workpiece and centering device or clamping systems.

In a device of the above type, a fork is attached to a horizontally movable swivel arm. The other end of the swivel arm is attached to an electric lifting device. This device has the same disadvantage as the forklift trucks already mentioned, namely that it is difficult to maintain the specified tolerance range when loading the machine. In addition, certain safety precautions must be observed when using electrical devices, so that their use is not possible everywhere.

The object of the invention is therefore to provide a device of the above-mentioned type with which millimetre-precise loading in a specific position and rotational orientation is made possible easily and safely.

The solution is that the lifting device is a pneumatically operated lifting cylinder, the holder has a weight sensor to determine the weight of the load placed on it and also a control device for automatic compensation of the weight placed on the

A lifting cylinder is provided which can be controlled via the signal from the weight sensor.

The device according to the invention allows weights to be moved without any effort. The manual guidance of the holder at a certain height, i.e. horizontally, is carried out by the operating elements. The sensor measures the weight on the holder and sends out a signal that controls the loading of the lifting cylinder via control valves. The weight of the load placed on it is thus determined and compensation is automatically triggered on the lifting cylinder. The influences of different load weights are automatically balanced out. Since only the friction forces of the joints of the swivel arm have to be overcome, easy manual movement of even heavy workpieces is possible without any problems. The device according to the invention also holds the preset position of the swivel arm regardless of the weight. This makes it much easier to load a machine precisely. This device also ensures that lifting and lowering movements can be sensitively controlled by the operating elements using the smallest additional forces or additional signals. In addition, the swivel arm can be lowered or raised, for example, by pressing down or raising the swivel arm, i.e. by applying force behind the weight sensor. The sensor does not register this load; therefore, no weight compensation takes place.

The lifting cylinder is guided in a frame that can either be anchored to the floor or is mobile. A column frame is preferred. For normal use, an adjustable lifting distance of around 500 mm is usually sufficient. With a range of around 600 to 1100 mm, for example, the usual work and machine table heights can be covered. For larger lifting ranges, especially for considerably lower working heights, it is advisable to arrange the column and lifting device next to each other when using a column frame. The swivel range of the swivel arm is then somewhat restricted, however.

The anchoring to the floor ensures that the entire device cannot tip over in any position, even when the swivel arm is extended. If several machines or workstations are to be served, the range of the swivel arm is often not sufficient. Instead of a fixed anchoring to the floor, a mobile frame is advantageous.

In order to achieve sufficient tipping safety for this variant during operation, one or more docking stations are preferably provided, which are anchored to the floor or wall. Before each use, a corresponding docking station is approached. It is particularly advantageous to provide the docking station with devices for supplying energy and/or air to the device according to the invention. A pure air supply for the actuation of the lifting cylinder is preferred.

and manual movement of the swivel arm horizontally, so that no supply of electrical energy, for example, is necessary. In this way, no cables need to be "dragged along", which always represent a certain source of danger for accidents. For safety reasons, it is advantageous to provide a locking mechanism for the swivel arm and/or the holder and/or the lifting device. For example, a basic position for the swivel arm can be defined, in which the holder is firmly fixed above the lifting cylinder and thus assumes the position with the least tendency to tip. For safety reasons, the mobile device can only be detached from the docking station in this basic position. Conversely, the locking mechanism is only released when docking at a new docking station, so that the swivel arm can be extended again. This release or blocking can be done either via the energy or air supply or mechanically, e.g. with a rod.

A particularly advantageous feature of the mobile version is a mount for counterweights on the frame. If the device is to be moved with a load on it, the counterweights ensure that the center of gravity of the device remains above the frame and is also low enough to ensure sufficient stability against tipping. Such weights can be provided on the back of the frame, i.e. on the side opposite the mounting position in the resting position, above the chassis.

The swivel arm is preferably an articulated arm, with which a nearly heart-shaped area around the anchoring point of the lifting column can be covered. The maximum possible radius is usually limited in practice for reasons of weight and stability. If the maneuvering space is limited, the articulated arm can be designed so that its arm segments can be placed on top of one another.

The design of the holder is arbitrary and depends on the workpiece or the geometry of the clamping system and the weight. In most cases, tenons or U- or L-shaped rail profiles are sufficient. If the workpiece has to be rotated from the horizontal position, for example when feeding lathes and cylindrical grinding machines or when assembling mold halves or when inserting pressure and injection molds into the corresponding machines, rotations from the horizontal to the vertical are necessary. Applications with a 180" rotation of the holder are also conceivable, for example to empty liquids from cavities or to be able to join the lower and upper parts of molds on the workbench when assembling molds. In this case, it is advisable for the holder to be mounted vertically and/or horizontally via at least one joint. Preferably, another rotation axis is inserted between the holder and the front joint of the swivel arm, which can be operated manually via a worm gear, for example. This has the advantage that it can be rotated in any position.

is self-locking. In the case of a central mass center or for other applications, other designs are of course possible.

The operating elements for controlling the recording are preferably handles attached to the joint head of the joint for the recording, which are advantageously designed as rotary handles. They allow the lifting cylinder to be supplied with more or less air via a corresponding valve control. By changing the rotary position of the handle, it is possible to raise or lower the lifting piston and thus adjust the height of the swivel arm and the workpiece. The handles advantageously have a reset device, for example via a spring tension, so that when the handles are released, the zero position is automatically assumed, i.e. no further movement takes place. Advantageously, a safety mechanism in the rotary handles means that the device can only be raised or lowered with both hands, namely by simultaneously operating both rotary handles. A locking mechanism is advantageously provided for this purpose. This two-hand operation ensures excellent accident protection, as the workpiece or the device itself cannot be touched during the positioning process. In contrast to loading via crane systems, where pendulum movements of the workpiece have to be manually compensated,

significant risks of collision, damage and injury are prevented.

In the following, embodiments of the present invention are described in more detail with reference to the accompanying drawings. They show:

Figure 1 is a schematic side view of a first embodiment of the present invention;

Figure 2 is a schematic plan view of the embodiment according to Figure 1 with a representation of the pivoting range;

Figure 3 is a schematic side view of a second embodiment of the device according to the invention with a foldable swivel arm;

Figure 4 is a schematic plan view of the embodiment according to Figure 3 showing the swivel range of the swivel arm, with machines/workstations also indicated;

Figure 5 is a schematic side view of a third embodiment of the device according to the invention with an enlarged stroke range;

·

10

Figure 6 is a schematic plan view of the device according to the invention according to Figure 5 with a representation of the pivoting range of the pivoting arm?

Figure 7 is a schematic side view of a fourth embodiment of the device according to the invention with an extended lifting range and foldable swivel arm;

Figure 8 is a schematic plan view of the embodiment according to Figure 7 showing the swivel range of the swivel arm;

Figure 9 is a schematic side view of a fifth embodiment with chassis and docking station; and

Figure 10 is a front view of the docking station from Figure

Figures 1 and 2 show, so to speak, the "basic model" of the device 10 according to the invention. In this embodiment, a column frame 12 is attached to the floor 11, for example by doweling. The column frame 12 contains a guide column 13 and a lifting cylinder 14. The air supply of the lifting cylinder 14 is the only energy supply in the embodiment. There are no electrical connections, for example. This saves, for example, further

Safety measures. The pneumatics of the lifting cylinder 14 and the air supply of the entire device 10 are not shown here. An articulated arm rod 15 is attached to the end of the guide column 13 or above the lifting cylinder 14. The articulated arm rod 15 consists of two arm segments 16 and 17, which are connected to one another via a joint 18. The rear arm segment 16 is bent, as can be seen in Figure 2. This makes it possible to arrange both arm segments 16, 17 parallel to one another. At its straight end, it is connected to the guide column 13 via a joint 19. The free end of the front segment 17 has an interface 20, which is attached to the front arm segment 17 via a joint 21. The joint 21 ensures the rotational alignment of the interface 20 and thus of the holder 22 in the horizontal. The interface 20 is used to attach various mounts 22, in the embodiment of a fork, and also carries handles 23, 24, which in the embodiment are designed as rotary handles and have a locking mechanism, which ensures that only both rotary handles 23, 24 can be operated at the same time. By rotating the rotary handles 23, 24, the lifting cylinder 14 is supplied with more or less air via cylinders and/or control valves (not shown). The rotary handles 23, 24 also serve to guide the articulated arm rod 15 or the mount 22 in the horizontal, which in the embodiment is purely mechanical. Since only the friction of the joints 18, 19, 21 has to be overcome due to the weight compensation, this also represents a safety factor with heavy loads.

no problem. Between the fork 22 and the joint 21, a weight sensor 25 is also provided as part of the interface 20. Not shown is another manually adjustable axis of rotation, for example in the form of a worm gear, which makes it possible to rotate the loads resting on the fork 22 into the vertical or even further.

The pneumatic height adjustment via the lifting cylinder 14 makes it possible to maintain the set height position in the event of a power disconnection or power failure. By applying force to the articulated arm 15 or to the joint 19, the device 10 can be gently pushed down or raised with relatively little effort. The weight sensor 25 does not register this effect, so that no weight compensation takes place. This also makes it easier to position the load on the holder 22. The weight sensor in front of the front joint 21 ensures weight compensation on the lifting cylinder 14, so that the device 10 independently holds every height point reached, regardless of the load. Operation via two handle elements 23, 24, which are designed as rotary handles, allows a lifting or lowering command to be triggered in addition to positioning the load in the horizontal plane by turning. These are the most important design elements of the embodiment shown. Also not shown are return spring elements in the handles 23, 24, which return to the

Return to zero position so that initiated
Movements come to a standstill. It is advantageous
Furthermore, in the joints 18, 19, 21 a certain
Minimum friction must be provided so that even when the device according to the invention is slightly inclined, the articulated arm 15 maintains its once set position.

Figures 1 and 2 also show the range of the
device 10 according to the invention. The
inventive device 10 according to this

For example, the design example has a fork 22 that is height adjustable from 780 to 1280 mm. The articulated boom itself is approximately 1400 mm long, measured from joint 19 to
including the weight sensor 25. This results in the range indicated in Figure 2, whereby the
Arrow Al symbolized radius just the 1400 mm length of the
Articulated boom linkage 15.

In Figure 1, the rest position of the
articulated arm linkage 15, as can be achieved by folding the front arm segment 17 in the direction of arrow B shown in Figure 2.

The anchoring to the floor 11 ensures that the device according to the invention is stable against tipping.

Figures 3 and 4 show in a comparable representation a further embodiment of the inventive
Device, wherein like parts are provided with like reference numbers. The device 110 has a pallet 122 instead of the fork. The middle joint 118 is designed in such a way
modified so that the arm segments 16 and 17
This creates a 360" swivel range
also possible in this joint 118. This embodiment is, as indicated in Figure 4, particularly advantageous,
when space is limited. The arrow A2 in Figure 4 indicates a radius of about 1800 mm, as indicated by
can be achieved with correspondingly longer arm segments 16, 17. The lifting range is between 800 and 1300 mm. The joint 19 can also be designed like the joint 18; then a 360" swivel range is available in both joints 18, 19.

A further embodiment 210 is shown in Figures 5 and 6. In this embodiment 210, the
Articulated arm linkage 15 is not attached to the upper end of the lifting cylinder 214 or the guide column 213, but to the side
offset from it. This increases the lifting range, in the example from an indicated minimum height of approx. 300 mm to the indicated maximum height of approx.
1300 mm. The swivel range of the rear arm segment 16 is
however, as can be seen from Figure 6, somewhat limited. The arrow A3 in Figure 6 again symbolizes the radius, which corresponds to the length of the articulated arm rod 15.

Figure 7 shows a further embodiment 310 of the present invention, in which the variants shown in Figures 5 and 6 or 3 and 4 are combined with one another, namely the offset arrangement of the articulated arm linkage 15 and the lifting cylinder 314 or guide column 313 as well as the joint 318, which enables the arm segments 16 and 17 to be placed one above the other. Figure 7 shows all the different variants of use, with the overlapping of the arm segments 16 and 17 being indicated by solid lines and the "unfolded ^" state and the various lifting heights being indicated by dashed lines. Figure 8 again shows the ranges for the various arrangements, with the arrow A3 symbolizing a range of approximately 1600 mm and the arrow A4 a range of approximately 900 mm in the folded state, ie with the arm segments 16, 17 lying one above the other. The arm segment 17 can be shortened as in the exemplary embodiment in order to avoid a collision with the column frame 312.

It can be seen that with all these variations, due to the articulated arm construction, an almost heart-shaped area can be covered around the anchoring point of the lifting cylinder 14, 214, 314. A common value in practice, as also indicated in the example, is a radius range of approx. 1500 mm, related to the center of the holder 22, with maximum loads of up to 150 kg. Other designs are of course just as possible.

Figure 9 shows an embodiment of a device 410 according to the invention with a chassis 440. In its structure, the embodiment 410 corresponds to the embodiment 10 shown in Figure 1. Of course, all other variants shown so far can also be provided with a chassis. The chassis 440 essentially consists of two beams, of which only the beam 441 is shown, and between which the column frame 12 is fastened. The beams can be connected to one another at one end by a cross beam 43. The chassis is provided with wheels 42. At least one end 444 of the beams 441 is free and has a part 445 of a safety lock with which the beams 441 can be fixed in a docking station 446. The docking station 446 essentially has two receptacles 447 _f 448 for the beams 441. The receptacle also has parts 449, 450 of a safety lock, which are complementary to the parts 445 of the spars 441. The docking station 446 is firmly anchored to the floor 11. The safety locks also have connecting elements (not shown here) for the energy supply, which in the exemplary embodiment is a pure air supply.

For safety reasons, the mobile device 410 can only be detached in the basic position of the device 410, as indicated on the left in Figure 9. For this purpose, a fork lock 426 is provided between the weight sensor 25 and the front joint 21, to which the articulated arm linkage 15

in the rest position, it is locked to the column frame 412. This fork lock 426 is only released when docking. The moment the articulated arm rod 15 is extended, the chassis 440 of the device 410 is automatically connected to the docking station 446 via the safety locks 445, 449, 450, so that the device 410 can no longer be removed. The connection to the docking station 446 is only released again when the fork lock 426 is actuated in the basic position. This blocking and release mechanism can be actuated either via the energy supply, i.e. pneumatically in the example, or mechanically, e.g. via rods or the like. In order to be able to undock and move the device 410 in the basic position without tipping over with the load placed in the fork 22, counterweights are provided. The spar sides 451 form a support surface for counterweights. The counterweights are attached to the side frame 412.

LIST OF REFERENCE SYMBOLS

10 448 contraption 11 450 Floor 12 Column frame 13 Guide column 14 Lifting cylinder 15 Folding arm linkage 16 rear arm segment 17 anterior arra segment 18 middle joint 19 rear joint 20 interface 21 front joint 22 mount, fork 23 Handle 24 Handle 25 Weight sensor 110 contraption 118 middle joint 122 Recording 210 contraption 213 Guide column 214 Lifting cylinder 310 contraption 313 Guide column 314 Lifting cylinder 318 middle joint 410 contraption 426 Fork lock 440 chassis 441 Holm 442 Wheels 443 Crossbar 444 End of 441 445 Safety lock on the handlebar 446 docking station 447, Recordings 449, Safety lock on the docking station 451 Holm side

Claims (18)

PROTECTION CLAIMS 1. Device for manually lifting/lowering and positioning loads, in particular for loading and unloading workpieces on machines, with a horizontally movable swivel arm (15), at one end of which a holder (22) for the load provided with an operating element (23, 24) is provided and the other end of which is attached to a lifting device, characterized in that the lifting device is a pneumatically operated lifting cylinder (14, 214, 314), that the holder (22) has a weight sensor (25) for determining the weight of the load placed on it at any one time, that a control device for automatically compensating the weight placed on the lifting cylinder (14, 214, 314) is also provided, which can be controlled via the signal from the weight sensor (25). 2. Device according to claim 1, characterized in that the lifting cylinder (14, 214, 314) is guided in a frame (12) that can be anchored to the ground. 3. Device according to claim 1, characterized in that the lifting cylinder (14, 214, 314) is guided in a mobile frame (412, 440). 4. Device according to one of claims 2 or 3, characterized in that the frame (12, 412) is a column frame with at least one guide column (13, 213, 313). 5. Device according to claim 4, characterized in that the guide column (213, 313) and the lifting cylinder (214, 314) are arranged next to one another. 6. Device according to one of claims 3 to 5, characterized in that the mobile frame (440) can be connected to a firmly anchored docking station (446). 7. Device according to claim 6, characterized in that the docking station (446) has devices for energy and/or air supply. 8. Device according to one of claims 6 or 7, characterized in that the docking station (446) has devices (426, 447, 449, 450) for locking the swivel arm (15) and/or the holder (22) and/or the lifting cylinder (14). 9. Device according to one of the preceding claims, characterized in that the horizontally movable swivel arm is an articulated arm linkage (15). 10. Device according to one of the preceding claims, characterized in that the swivel arm has arm segments (16, 17) which can be placed one above the other at different heights. 11. Device according to one of the preceding claims, characterized in that the receptacle (22) is mounted so as to be vertically and/or horizontally rotatable via at least one joint (21). 12. Device according to claim 11, characterized in that a joint operable via a worm gear is provided for the vertical rotation. 13. Device according to one of the preceding claims, characterized in that two handles (23, 24) are provided as operating elements, with which the holder (22) can be moved in the horizontal direction and the supply of more or less air to the lifting cylinder can be controlled. 14. Device according to claim 13, characterized in that the handles (23, 24) are designed as rotary handles, wherein the control of the lifting cylinder (14, 214, 314) takes place via the rotation. 15. Device according to one of claims 13 or 14, characterized in that the handles (23, 24) are provided with a return device. 16. Device according to one of claims 13 to 15, characterized in that the handles (23, 24) have a locking mechanism which triggers lifting movements only when both handles (23, 24) are actuated simultaneously. 17. Device according to one of the preceding claims, characterized in that the frame (12, 412) has a receptacle for at least one counterweight. 18. Device according to one of the preceding claims, characterized in that the joints (18, 19, 21) of the articulated arm linkage (15) are provided with a minimum friction.