DE10005153C2 - Gripper device for a lift truck - Google Patents

Description

The invention relates to a gripper device for a lift truck with two in it Opening width adjustable flat clamp arms, their length in Essential for grasping several in a row and / or several payloads arranged next to one another are dimensioned and which a control circuit for setting and / or displaying the Bracket force are assigned. The gripper device can in particular as Stapler to be designed.

With such attachments or gripping devices it is possible to be agreed to take payloads between the clamp arms or jaws men, by exerting a force to hold it in place and without bottom Un support by moving the loader to a desired location bring.

It has already been recognized in DE-PS 908 471 that in the handha Exercise of different heights with boxes of citrus fruits or the like it makes sense that the force exerted on the stack of boxes is proportional or in any case depending on the total mass or the total weight the stack of crates or other payload. Will be too low Exerted pressing force, the clamp arms can not hold the stack of boxes; is a contact force that is too great for the current stack of boxes exercised, this affects an area of the payload that is too small, which leads to damage damage or destruction. The increase in contact pressure depends of the payload is also in EP 0 529 488 A1 by appropriate mechani constructions have been guaranteed.

However, such constructions have the disadvantage that they are due to current, for example from the driving situation of the loader Forces when driving over bumps or slopes react undesirably, because these forces also with the constructions be implemented.  

DE 38 01 133 C2 and DE deal with another problem EP 0 244 984 A2. Here, using photo sensors, for example a light barrier ken, measured the depth of the lift truck to ensure that the ent speaking payloads are also correctly and completely recorded. example wise only one or more of several boxes in a row also several, but of course completely handled. This concept however, they are quite complicated and prone to errors. Light barriers and Photodetectors can easily become dirty, especially in harsh environments then cause malfunction.

In contrast, the object of the invention is a gripper device for a Propose a loader with which in a technically simple and as little as possible error-prone form a reliable transport of several in particular cuboid payloads is possible.

This problem is solved by a gripper device for a lift truck two flat clamp arms adjustable in their opening width, their length essentially for gripping several in a row and / or several payloads arranged next to one another are dimensioned and which a control circuit for setting and / or displaying the bracket force is assigned, in which a pendulum axis on at least one of the surfaces gene brackets is provided in which this pendulum axis in the middle Be is arranged richly of the clamp arm and extends essentially vertically, so that the area of this clamp arm facing the payloads around the Pendulum axis can swing, in which a limiter is provided, the maximum pendulum angle of the surface facing the payloads from the Parallels to the opposite surface of the other bracket arm limited, and in which a switch is provided depending on the Errei Chen this maximum pendulum angle emits a signal that the control scarf device for setting and / or displaying the clamp force is supplied.

Such a design surprisingly solves the problem, both extraordinarily reliable as well as technically quite simple and inexpensive.  

In a different context, such pens are used for clamp arms for forklifts delaxes are already known, for example from US Pat. No. 2,674,387 or EP 0 244 984 A2. If only boxes with similar products exist, there are nevertheless certain dimensions Fluctuation. The size of the boxes, for example  for washing machines or refrigerators is usually the case not particularly critical and can therefore take a few millimes ter differ from each other.

Now try using several of these with bracket arms Taking boxes at the same time may be egg ner of these boxes a little wider than the other, so one The pair of clamp arms grasp the larger of these boxes well could, the slightly smaller box but by the small gig clamped arms fall through or could slip out. This can be avoided by one of the two bracket arms on one essentially vertical pendulum axis is suspended and at Moving the two clamp arms swinging suspended bracket arm so it has the ability to move freely the possibly slightly graded shape of the given to adapt to cardboard areas. The bracket arm stands therefore, if necessary, slightly oblique. It's just about angles from a few minutes of angle or maybe a few win kelgraden. If this bracket arm is slightly inclined, so it holds both the larger and the slightly small carton. The other bracket arm can be conventional stay educated.

This for a completely different purpose ning and useful pendulum suspension of one bracket poor can now be exploited according to the invention to help solve the problem of interest. This pendulum hanging bracket arm behaves namely in the complete absence of one box so that it is this goes to a maximum position. Because he will with no payload and no carton in its pendulum limited movement and travels to the maximum stop inside, since the clamp arm is not protected by a "small" Carton is braked. This maximum stop is also na Of course, only a few degrees from the parallels to the bracket arm offset. The other, peered outside delte side of the bracket arm so grips the existing Carton still tight.

The switch provided according to the invention now adds for example when this maximum pendulum angle is reached a signal from that of the control circuit for adjustment and / or display of the clamp force is supplied. The Reaching this maximum pendulum angle at the limiter implicitly indicates the absence of a box, so the Control circuit now in the inference from this signal Set clamp force correctly or at least one can submit the corresponding advertisement.

The clamping force can be optimal on the number of boxes be matched between the two bracket arms.

The control circuit therefore has exact information about whether there are one or two payloads in a row the and can accordingly the required clamping force request of the two clamp arms.

Instead of giving a signal when the maximum is reached vice versa, of course, a signal can always be emitted ben, which is switched off when it is reached or it can depend on the angular position of the signal different signals are given.

Typically, you can use two bracket arms  not just one after the other, but also side by side or several boxes are included. Whether this is the However, the attachment can also be used without any additional Measure how far the two clams arms have moved apart. So this requires no additional switches.

It is also significantly easier than in the prior art determine whether there may be several on top of each other Payloads are located between the bracket arms. It is namely also possible another, essentially hori provide a pendulum axis running zontally. This can ent not be provided on the other bracket arm or but on the same bracket arm with the first pendulum cross axis so that a point suspension for the force transmission is provided on the bracket arm, so a kind of universal joint arises.

Such a horizontal pendulum axis is now also provided in such a way that they are approximately equal to the Top edge of a cardboard box below, so can immediately detected by a similar limitation function whether one or two boxes are on top of each other.

A combination of the different signals can Then evaluate the control circuit directly to determine whether just one box, two boxes side by side, one behind the other or on top of each other, four boxes in one area from two boxes twice or in two layers to two Boxes on top of each other or possibly eight boxes are between the two bracket arms. For each In these cases, it can determine the optimal clamping force and use or at least indicate that a sol che clamping force should be applied.

Are, for example, between two brackets a total of eight payloads, two on top of each other lying layers of four arranged in a square Cardboard boxes, this is done without any great effort the attachment is found. The two switches on one Brackets determine that they are not at their maximum po sition, that is, they are each loaded with two boxes and the attachment also automatically detects that the two clamp arms when moving together exactly that Have a distance equal to the width of two boxes speaks. The corresponding message to the signal processing tion and control unit shows that the clamping force the bracket arms must be large enough to hold a total of eight Hold boxes. At the same time, there is also a guarantee making sure that the side surface of four boxes each to absorb this corresponding clamping force and there with to distribute the resulting pressure stands so that damage can be avoided.

In contrast, there is only a single box between exactly the same bracket arms, so both scarf react accordingly, since the bracket arm around both Pivots pendulum axles to its maximum position; UNMIT telbar in front of the lift loader, since there is no box stands, and inward about the horizontal axis because only there is a box below. The switches report to the Si Signal processing and control unit, therefore, the not appropriate boxes.

The distance between the clamp arms corresponds to the width ei Cardboard boxes so that the control unit has enough clamping Kraft for a box that also provides accordingly from the side wall of this one box he easily can be worn.

The same applies to all transportable intermediate items solutions, for example for a single layer of four boxes arranged in a square or for four in two rows hen stacked payloads. Every constellation tion can he from the signal processing and control unit known and considered accordingly.

The driver of the lift loader does not have to do any switching operations, Take observations or take other measures, to influence the force of the clamp arms. Thereby possible incorrect operations are of course also made out closed.

The actual design of the switches can be found in ver different form. The requirements for this Switch is relatively simple. You just have to be able determine that the maximum value has been reached and for this purpose can either be a switch that responds to a stop, a Pressure switch, but of course also one in the pendulum axis self-located suitable electronic switch ver be applied, which determines that a certain rotation has taken place or has just not taken place.

All of these switches are insensitive and inexpensive and remain with possible soiling that in the harsh climate can occur in the lift loader work without any influence on the radio tion.

Theoretically, a conception is also conceivable that more as two one above the other and / or one behind the other and / or ne can detect boxes arranged next to each other. For this would have to be two in the case of three cardboard boxes that can be taken up in succession Pendulum axes are provided, which are then each through Reaching the maximum positions in one way or another on the other side to determine which relative occupations by the Cardboard boxes can be seen between the clamp arms.

Of course, the existence of one, two or three boxes arranged one above the other with several horizontal pendulum axes. Derar Conceptions would only be in clear ones Special cases of interest.

The gripping device can be an integral part of the Lift loader, but their separate execution is preferred tion as an attachment.

In the following, an execution is based on the drawings Example of the invention explained in more detail. Show it:

Figure 1 is a plan view of a schematic representation of an attachment according to the invention.

FIG. 2 shows a top view of the attachment from FIG. 1 with another load; FIG.

Fig. 3 is a plan view of the implement of Figure 1 at a third loading.

FIG. 4 shows a plan view of the attachment from FIG. 1 with a fourth loading; FIG. and

Fig. 5 is a schematic representation of a circuit diagram for the overall concept.

A preferred embodiment of the invention can be seen from above in FIG. 1. On the left in the picture you have to imagine the lift loader or forklift. On this, the only schematically shown attachment advises, which can be moved up and down as usual, for example to remove boxes with washing machines from a high rack.

The attachment consists of various components that coordinate this movement and which are not shown in the figures, but also in particular from two clamp arms 1 and 2 . These clamp arms are clamping jaws that have vertically oriented clamping surfaces for contacting the payload to be transported, for example the boxes K. These bracket arms 1 and 2 can be moved against each other and away from each other. This is indicated in FIG. 1 by the fact that a position is shown in which the clamp arms 1 and 2 are arranged relatively close to one another.

In a second position it is shown in FIG. 2 that the clamp arms are spaced sufficiently far apart to accommodate two cardboard boxes K with payloads placed next to one another. In the first position in FIG. 1, exactly one carton K fits between those in the clamp arms 1 and 2 .

Two switching elements 7 and 8 are provided which tap the current position of the clamp arms. Since a certain attachment is usually hen only for transporting a very specific type of box of predetermined size, from which only a very specific number of either one or two pieces should be added next to one another between the clamp arms 1 and 2 , the switching elements 7 and 8 also simply by stating a "yes" and a "no" statement to clarify whether there may be one or two boxes between the clamp arms 1 and 2 . It is of course also possible to tap this data directly from the motion control of the clamp arms 1 and 2 .

The clamp arms 1 and 2 , that is to say the clamping jaws with their clamping surfaces running in a vertical plane, protrude from the base approximately into the space by a depth of two cartons. In this way, the clamping surfaces can also be pressed precisely against the side walls of the cartons K if one or two of these are oriented one behind the other. This applies to both bracket arms 1 and 2 .

Only on one of these clamp arms, namely the clamp arm 2 arranged on the right side in FIG. 1 by the driver of the forklift truck, is a pendulum axis 9 seen before. The clamp arm 2 with its inner surface facing the cartons K with the payload can oscillate around this pin delachse 9 . The pendulum axis 9 itself is mounted on a support frame 10 , which in turn carries out the aforementioned displacement movements.

As can be seen in FIGS. 1 and 2, there are cardboard boxes K only in the front areas facing away from the lift truck, namely in FIG. 1 a box and in FIG. 2 two boxes. In contrast, there is no payload in the areas adjacent to the lift truck. This results in that the lift truck is of from facing region of the clamping arm 2 at Zusammenfah of the clamping arms 1 and 2 ren by the cartons K beauf beat that does not Dage the lift truck adjacent region gene. As a result, the clamp arm 2 rotates clockwise about the pendulum axis 9 in FIG. 2 until it reaches a maximum value. Further rotation in this direction is prevented by a limiter, not shown. This limiter can be a mechanical lock of the simplest type.

In the figure shown, the outermost end of the clamp arm 2 facing the lift loader is equipped with a switching flag 11 . This switching flag 11 , which can also be seen in FIG. 1, is in both figures at its most inward-facing position. As a result, it is separated and not in contact with a Schaltele element 12 , which is located in the base region of the support structure 10 , that is, where the support structure 10 connects the bracket arm 2 to the base. The switching flag 11 forms a switch together with the switching element 12 .

Fig. 3 now shows a situation in which the clamp arms 1 and 2 enclose two boxes K with payload arranged one behind the other. Similar to FIG. 1, the switches 7 and 8 for determining the opening width are consequently in position in relation to one another in such a way that they determine that only one carton K can be located next to one another in the two clamp arms 1 and 2 .

On the other hand, the surface of the clamp arm 2 , which faces the cartons K with the payload, is now applied in its entire area. This uniform application of the surface of the clamp arm 2 now leads to the fact that the clamp arm 2 is acted upon both in front of and behind the pendulum axis 9 with forces, so that the clamp arm 2 itself is not in its maximum position but in a balanced position deviates from an average value only by slight dimensional fluctuations or tolerances of the cartons K.

Compared to the situation in FIG. 1, this leads to the switching flag 11 moving outwards counterclockwise (compared with FIG. 1) and thereby coming into contact with the switching element 12 . The switch 11 , 12 determines this contact and emits a corresponding signal.

Fig. 4 shows a representation similar to Fig. 2. Here, the switches 7 and 8 determine that there are two side by side on ordered boxes K with payload between the clamp arms 1 and 2 . Similarly as in Fig. 3, however, the clamp arm 2 is acted on the supporting stand 10, in turn, both before load and behind the swing axle 9 by boxes K with payload, so that here also the switching flag 11 in case of contact comes with the switching element 12.

From a representation now the corresponding pen del movements about an approximately horizontal pendulum axis apart from here. This can alternatively or additionally pre will see.

The total of four switches or switching elements 7 , 8 , 11 , 12 are able to specify exactly how many boxes K with payload are in which configuration between the clamp arms 1 and 2 . If, for example, no switches are actuated, it can easily be concluded 1 that there are obviously no boxes K in the rear area adjacent to the loader, that is to say only canons are located in the front area between the clamp arms 1 and 2 .

In addition, from the non-actuation of the switches 7 and 8, it can also be concluded that the clamp arms 1 and 2 have not moved together, that is to say they have two boxes ne next to one another. So there are exactly two boxes between the bracket arms 1 and 2 , in the front area. This corresponds to the situation from FIG. 2.

In another example, the switching elements 11 and 12 are actuated, so it can be concluded with similar considerations that there are a total of four canons in a quadratic arrangement in the lower level between the bracket arms 1 and 2 .

In practice, the drivers of lift loaders always pick up individual boxes K only at the front between the clamp arms 1 and 2 , that is to say in the area which is remote from the forklift truck and is furthest away from it. This has practical reasons, so that the clamp arm does not have to be inserted into the area that is difficult for the driver to see behind the box. This behavior allows only one extreme position to be provided, namely the absence of a payload adjacent to the lift truck. But it would also be easily possible to provide a further scarf arrangement for reaching another extreme value in the absence of a payload on exactly the other, namely the side facing away from the forklift, because the clamp arm with its pendulum axis would then behave accordingly. The signal processing and control unit 18 would then of course still be fed appropriate additional signals for consideration.

Fig. 5 shows schematically the control of such an order. In the lower half of FIG. 5 is a representation similar to FIG. 4 rotated 90 ° and mirrored to recognize NEN. The switching elements 7 , 8 , 11 and 12 are to be recognized here. From both switch groups, two lines each go to a signal processing and control unit 18 , to which the total of two pieces of information are supplied. A power supply 13 makes it possible to determine this simply by applying voltage to the corresponding switch, but it is of course also conceivable to use another design.

In the image below are also two hy draulic cylinders 23 and 24 , with which the clamp arms 1 and 2 can be moved apart and moved together, these two hydraulic cylinders also exerting the clamping force with which the jaws or clamp arms 1 and 2 with their clamping surfaces the boxes K arranged between them act with the payload.

In the upper half, the control area is indicated purely schematically. At the top left is the forklift hydraulic 15 which performs the basic functions. This actuates the hydraulic valve 15 for the clamp and sideshift function. The hydraulic valve 16 be, as already discussed, the hydraulic cylinders 23 and 24 in a conventional form.

From the signal processing and control unit 18 who supplied the processed data of the switching elements 7 , 8 , 11 and 12 to a multi-stage pressure valve 17 , which then calculates the required pressures from these data or ascertained and with these data additionally the hydraulic valve 16 for the clamp - and sideshift function is applied. As a result, in addition to the movements of the clamp arms 1 and 2 desired by the driver, the necessary clamping forces are now also taken into account by the hydraulic cylinders 23 and 24 , which are dependent on the number and arrangement of the boxes K with the payloads.

LIST OF REFERENCE NUMBERS

1

clamp arm

2

clamp arm

7

Switching element for determining the opening width

8th

Switching element for determining the opening width

9

swing axle

10

shoring

11

Schaltfahne

12

switching element

13

power supply

15

forklift hydraulic

16

Hydraulic valve for clamp and sideshift function

17

Multi-stage pressure valve

18

Signal processing and control unit

23

hydraulic cylinders

24

hydraulic cylinders
K carton with payload

Claims (8)

1. Gripper device for a lift truck with two adjustable clamp arms adjustable in their opening width ( 1 , 2 ), the length of which is essentially dimensioned for gripping a plurality of payloads arranged one behind the other and / or several adjacent one another and for which a control circuit for the adjustment and / or display of the bracket are assigned by force,
in which a pendulum axis ( 9 ) is provided on at least one of the flat clamp arms ( 2 ),
in which this pendulum axis ( 9 ) is arranged in the central region of the clamp arm ( 2 ) and extends essentially perpendicularly, so that the surface of this clamp arm ( 2 ) facing the payloads (K) can oscillate around the pendulum axis ( 9 ),
in which a limiter is provided which limits the maximum pendulum angle of the surface facing the payloads (K) from the parallel to the opposite surface of the other bracket arm ( 1 ), and
in which a switch ( 11 , 12 ) is provided which, depending on the extent of this maximum pendulum angle, emits a signal which is fed to the control circuit ( 18 ) for setting and / or displaying the clamp force. 2. Gripper device according to claim 1, characterized in that a second pendulum axis is provided, which is arranged in the central region of the same bracket arm ( 2 ) or the other bracket arm ( 1 ) and extends essentially horizontally, so that the payloads (K) facing surface of this clamp arm can swing around the pen delachse. 3. Gripper device according to claim 1 or 2, characterized in that the clamp arms ( 1 , 2 ) are designed such that two useful loads (K) could be gripped one behind the other, side by side and one above the other. 4. Gripper device according to one of the preceding claims, characterized in that a switch element ( 11 ) is arranged on the side of the clamp arm adjacent to the lifting arm ( 2 ) with the pendulum axis ( 9 ) and cooperates with a further switch element ( 12 ) which cooperates with one Support frame ( 10 ) for the pendulum axis ( 9 ) is also arranged. 5. Gripper device according to one of the preceding claims, characterized in that the switch element (11) has a switching lug and that the other switch element (12) to contact by the switch lug (11) responding. 6. Gripper device according to one of the preceding claims, characterized in that the device for detecting the lateral adjustment of the clamp arms ( 1 , 2 ) one or both clamp arms ( 1 , 2 ) associated switch elements ( 7 , 8 ), the position of which is selected is that they detect a distance between the clamp arms ( 1 , 2 ) required for gripping two payloads (K) arranged next to one another. 7. Gripper device according to one of the preceding claims, characterized in that the measurement data of the switches ( 7 , 8 , 11 , 12 ) are fed to a signal processing and control unit ( 18 ) and are converted into corresponding clamping forces by the latter. 8. Gripper device according to one of the preceding claims, characterized in that the data of the signal processing and control unit ( 18 ) are fed to a multi-stage pressure valve, the output data of which are fed to the hydraulic valve ( 16 ) for the clamp function.