System and device for controlling a load lifting device

Translation of description of equivalent WO 0047512 A2

System and method for controlling a load lifting device

The present invention relates to a system for controlling a load lifting device, connected to a controllable drive, with the drive, - at least in a rest position by gravity - vertically aligned carrying element, with a connected to the support element for lifting gear and a control loop for load balancing. The invention further relates to a feasible in particular by means of such a system control method.

Systems of the type mentioned are known with an electric motor and fluidly driven load lifting devices. They are used to avoid a higher physical effort in hand-guided movements held on the lifting accessory loads of all kinds. As a result of load balancing while hovering the load in a selected height and can be performed with minimal force in their determination position. Such a system, which nenkonstruktion one on a running track comprises at least one horizontal direction guided crane trolley, is known for example from German utility model DE 297 19 865 Ul. The support element of the known lifting devices can be flexibly and on a drum wound (rope, chain) or can also be rigid.

A lifting device with a rigid supporting element is known for example from DE 4342715 AI. In this publication, a hand-operated manipulator is described which has a vertical bearing pin, about which a horizontal cantilevered support arm is pivotable. At its end remote from the bearing pin of the carrier arm carries a lifting device, having at its lower end, a load receiving means. The supporting arm consists of two series-connected partial arms which are joined together by a joint with a vertical pivot axis and thus form a so-called articulated. The arm has a further formed of two partial arms articulated, which complements the first one to lie in a horizontal plane changeable parallelogram.

In some prior art control systems for lifting devices, the size of the tare and the load to be absorbed must be set on a controller. To avoid this disadvantage, as disclosed in EP 0733579 Al is known, also be provided means for determining the weight on the load lifting device.

The present invention has for its object to provide a control system of the type mentioned and a corresponding method, with no weight setting the load balancing can be implemented in tax technically simple manner, with a comfortable operation is to be ensured with high security.

According to the invention this is achieved in that the control circuit for load balancing comprises means for generating a path-dependent signal corresponding to a substantially vertical movement of the supporting element and serves as input signal for the control of the drive.

After receiving the load in the load receiving means can so advantageously an applied force from the drive or a corresponding torque can be automatically increased rapidly until it (s) corresponding to the weight of the load. The increase in the driving force can at elektromorischem drive by a motor current control or fluidic drive by controlling the fluid pressure, for example by means of a servo valve, occur. The timing of the achieved weight compensation can be determined by using the device for generating the path-dependent signal. The balance condition has been set when under the action of the drive uses the substantially vertical movement of the supporting element. The size of the path-dependent signal can be compared advantageously with a desired value and, if this is achieved, the applied by the driving force or the torque at the value reached can be kept constant. The weight balancing is thus completely automatically. The detection of the desired value takes place here in the millisecond range, making it so quickly that the vertical movement of the support element is not perceived by the operator and therefore in the operation also can not interfere.

The drive can principally be an electric motor, said means for generating the path-dependent signal, as is the case in particular in an electric servo motor, wherein the path-dependent signal a Rotation angle corresponds to and can be picked up directly by the engine. For other electric motors may be provided for example with an advantage that the device for generating the path-dependent signal a coaxially to the drive shaft of the motor arranged, incremental Drehwinkelmeßscheibe is.

The invention can advantageously also come with lifting devices for use in which the drive has a fluidically acting drive device, such as a pneumatic piston-cylinder arrangement or a pneumatically acted ballscrew is.

In sense of a further user-friendly design of the system, a controller for the vertical movement of the support element may be provided which comprise a control member, a handling device for the load receiving means, and means for generating a force-dependent signal, wherein the force-dependent signal of a handling device vertically acting manipulation force corresponds and the control member is designed such that it from a target value emits in dependence on the deviation of the kraftabhangigen signal a control signal for driving to induce a movement of the support member, which corresponds to the direction and preferably also the magnitude of the manipulation force.

In a further embodiment of the invention, thereby both the setpoint and the transmission behavior of the control member by an adjusting member in dependence on one of the load can be changed corresponding signal. Such implementing regulation allows advantageously a compensation of the system according to the invention up passing load-dependent friction Strengthens s.

Another advantage of the invention is that all members of the inventive system having a control or regulating function, such as be the control member of the controller for the vertical movement of the support member, the setting member for the nominal value of this control, etc. components of a single programmable logic controller can.

Further advantageous features of the invention are contained in the dependent claims and the following description.

Using preferred, illustrated in the drawing embodiments, the invention will now be described in more detail. They show:

Fig. 1 shows a schematic representation of the application of a system for controlling a load lifting device,

Fig. 2 shows a section through a lifting assembly of a system according to the invention with an electric motor acting actuator,

Fig. 3 is a schematic representation of the control of a system according to the invention,

Fig. 4 is a front view of a handling device of it, indungsgemäßen system in a first embodiment

Fig. 5 is a partially sectioned side view of a handling purification facility of an inventive system in a second embodiment,

Fig. 6 shows a section through a lifting unit with an inventive system fluidly acting actuator, in a simplified representation

Fig. 7 is a longitudinal section through a safety device for an inventive system with particular fluidically acting actuator,

Fig. 8 shows a further embodiment of a system according to the invention, with a rigid support member.

In the various figures of the drawing, the same parts are always provided with the same reference numerals, so that they will each usually described only once.

Referring to FIG. 1, a system for controlling a load-lifting device 1 to a controllable drive 2, which is arranged at a lifting unit the third The lifting unit 3 is designed as a guided on a running rail structure 4 in at least one horizontal direction XX crane trolley. is associated with the drive 2 a - at least by gravity in a rest position - vertical ZZ aligned carrying element 5. The supporting element 5 is rope that is wound flexible (limp) and, which is integrated inside the Hubaggregates 3 drum. 6

As the lifting unit 3 can be designed in detail, shows in a first variant, shown in FIG. 2 Sectional view. The lifting unit 3 has a housing 3a, in which the electric motor acting actuator 2, a servo motor and the drum 6 for winding the rope are.

connected to the support element 5 is a Lastaufnähme- means 7. With this, it is in the illustrated case to a device having a manually operable by an operator 8 load suspension mechanism, in particular with a chuck for receiving a load 9 with a cylindrical receiving opening, such as a Kitchen sink.

At the free end of the support member 5, a handling device 10 is attached to the load pickup means 7, which also serves for guiding the movement.

As the schematic representation shown in Fig. 3 of the control of a system according to the invention, this comprises a control circuit for load-balancing. In this control circuit means 11 for generating a path-dependent signal S is provided, which corresponds to a substantially vertical movement of the supporting element 5 and serves as input signal for controlling driving of the second The control circuit further includes a control element 12, which is designed so that it can output depending on a deviation .DELTA.S of stroke depended signal S from a target value W to an actuator 13 for driving 2 a control signal R for the movement of the support element. 5 The actuator 13 may, for example, means for changing the engine torque (manipulated variable I) of an electric motor, such as the servo controller shown in FIG. 2, or the pressure Q in a fluidic device such as the servo valve shown in FIG. 6 may be. After receiving a load 9 by means of the load lifting device 7 an applied by the drive torque is automatically 2 rapidly increases until it corresponds to the weight of the suspended load. 9 Here 9 the path-dependent signal S is determined to determine the setting of an accomplished balance state for the load. This signal S includes an information about the start and the start of an incipient extending to counterbalance load movement. The path-dependent signal S is compared with the setpoint W compared (formation of deviation .DELTA.S). If conformity of signal S and setpoint W is present (.DELTA.S = 0), the force applied by the drive 2 torque is kept constant at the value reached. For constant circuit while the control signal is R. The movement of the support element 5 and the load 9 is characterized to a halt. The set point can be preset extremely small with advantage. The constant engine torque or the pressure Q constitutes a measure for the weight of the load located on the load pickup means 7 and 9 may be used as a corresponding signal is processed.

The use of a servomotor as a drive 2 offers the advantage that it already has the means 11 for generating the path-dependent signal itself or forms, as it provides a path-dependent signal S (for an angle of rotation α of the drive shaft).

The inventive system can advantageously, as also apparent from Fig. 3, have a controller for the vertical movement of the supporting element 5 ZZ. The control system illustrated comprises a control member 14, the handling device 10 for the load receiving device 7, and a device 15 for generating a kraftabhängi- gen signal P, the one corresponding to the handling device 10 is substantially vertical ZZ acting manipulation force F. The control member 14 can be designed such that it from a target value V outputs a control signal T for the drive 2 to trigger a movement of the support element 5 in response to a deviation of the force-dependent signal P .DELTA.P. This movement can then preferably conform to the direction and preferably also the size of the manipulation force F.

Fig. Figure 3 illustrates further that the system according to the invention may comprise an adjustment member 16 that changes the target value V for the power signal P in response to a load 9 corresponding signal (for example, current I, pressure Q) of the handling device vertically acting manipulation force F corresponds. In addition, the adjustment member 16 may be also designed so that it changes the response of the control element 14, which, depending on the deviation .DELTA.P of force - write signal P from the target value V, the control signal T for the drive. As already mentioned, such a servo control is advantageously adapted, occurring in the system according to the invention load-dependent frictional forces to compensate, for example, to the drum 6 for the support element 5 or in a transmission. The manipulation force F can be minimized in this way.

The control for the vertical ZZ movement of the support element 5 - including the power to the load movement - can (with and without guidance control) regardless of the existence or the nature of the regulation of the load balancing used. For example, the drive 2 of a system without un- level circuit for load balancing be speed-controlled indirectly through the manipulation force F. Such a control is for example particularly suitable for the palletizing of loads 9, wherein the 5 takes place a vertical Z-Z movement of the support element as HauptZustellbewegung from top to bottom. It can be slowed down depending on the size of the path-dependent signal S with advantage the vertical ZZ movement of the support element 5 (downward movement). For example, as a very "gentle" load depositing 9 take place, because the target value V and the response of the actuator 16 can be made to the last part of the vertical ZZ transport path that a - compared with the situation in the rest of transport - greater manipulation force F corresponds to a shorter path of the supporting element 5 and the thereon lifting accessory. Such a possibility illustrates the 3 registered in Fig. As a dashed line drawn Signalflußbahn for the path-dependent signal S.

The inventive system can to increase the occupational safety of the operator be 8 equipped with several safety features. Thus, - this appears from Fig. 3 - a safety control for a manually operable load lifting mechanism of the load pickup means 7, in particular for a clamping or grasping mechanism, such as the collet chuck illustrated in Figure 1, may be provided.. Such safety control may include an affiliate of the device 11 for generating the path-dependent signal S and the device 15 for generating the path-dependent signal P Safety control member 17, which disables the manual operation of the Lastaufnähmemecha- mechanism and only releases (signal B) if at present kraf dependent signal P no path-dependent Signal S is present. The latter is the case when the load 9 is built on a support. Despite a particularly vertically directed ZZ downward manipulation force F, the load is no longer moved 9 and consequently also no path-dependent signal S is longer detected.

The path-dependent signal S can be further also be used to bring about braking when exceeding a maximum travel speed of the support element. 5

For the drive 2 and / or for blocking the movement of the support element 5 is another safety controller can be integrated in the system according to the invention. Also these, Fig. 3. This safety system may include a sensor 18, in particular a light barrier, for registering the use of the handling device 10 and a switching member 19, which switches off the drive 2 and blocks the movement of the supporting element 5 and only then turns or release (U signal) when the sensor 18 the use of the handling device 10 signals (signal A).

The regulating member 12 of the control circuit for load-balancing and / or the control member 14 of the control system for the vertical movement of the supporting element 5 and / or the adjusting member 16 for the desired value V of this control and / or the switching - element 19 of the safety controller for the drive 2 and for blocking the support element 5 and / or the safety and beauty-control member 17 of the safety controller for the load receiving means 10 can advantageously be individually or together components of a programmable logic controller PLC. This is angedeu- in Fig. 3 by comprising the components mentioned polyline tet. In particular, a very convenient and flexible influence on the dynamic behavior of the control system is in addition to the individual adaptability to the most varied handling tasks by the programmable logic controller PLC due to a digitized signal processing possible.

The programmable logic controller PLC can be used advantageously in the vicinity of the drive 2, in particular, be in the drive 2 receiving lifting unit 3 is arranged, as already Fig. 2 shows.

Fig. 4 shows an example of how one in Fig. 1 denoted by reference numeral 10 handling device of a system according to the invention can be formed. The handling device 10 is designed for a Beidhandbedienung by the operator 9, and has a frame-like shape. It is essential for the illustrated embodiment is that the handling device 10 is composed at least of two main parts 101, 102, of which the first part 101 on the one hand at an upper cross member 103 fixed to the support element 5 (fixing point 5a) and on the other hand fixed to a lower cross-strut 104 with the lifting gear 7 (chuck) is connected. The two transverse struts 103, 104 of the first portion 101 are secured via laterally arranged pipe-like connector 105 to each other so that said frame-like basic shape.

The second, the attack of the manipulation force F serving part 102 is arranged movable relative to the first part 101 and has a smaller overall length than the first part 101. It also includes a cross member 106 extending between the two transverse struts 103, 104, in particular is in the vicinity of the upper cross bar 103, the first part of the one hundred and first On the transverse strut 106 of the second portion 102 is also laterally arranged pipe-like connector 107 are attached, each form handles for the manual operation, comprising tubular connectors 105 of the first part 101 concentrically and are mounted on the underside resiliently on the first part of the one hundred and first At each handle about half the manipulation force F / 2 is effective in operation.

As the means 15 for providing the force-dependent signal P, as has been explained with reference to Fig. 4, is connected to the handling device 10 at least one, in particular inductive, sensor records the occurring under the effect of the manipulation force F relative change in position of the two parts 101, 102 arranged. The transducer signals in particular a change .DELTA.H (see. Also FIG. 4) of a distance H between the upper cross member 103 of the first part 101 and the cross member 106 of the second portion 102 of the handling device 10.

Fig. Figure 4 shows the other terminals 108, 109 to the compressed air supply to the load pickup means 7 and to the voltage supply, which are located on the upper cross member 103 of the first part 101. In addition to the cross-member 106 of the second part, a power switch 110 and a switch 111 for controlling the vertical ZZ movement of the support element 5 are arranged. Further switches 112, 113 for manual operation (Beidhandbedienung) are located on the two formed as handles tubular connectors 107 of the second part 102. These serve to activate the pan or the release function Collet. As already mentioned, the manual operation, in particular the release function of the load receiving mechanism can be locked and only then released by the safety control by means of a safety control member 17, when present in force-dependent signal P not a path-dependent signal S is present.

Fig. 5 shows a further embodiment of a handling device 10 of a system of the invention. This handling device 10 is designed for one-handed operation by the operator 8 and has an elongated shape. Also for this embodiment, it is essential that the handling device 10 is composed at least of two main parts 101, 102, of which the first part 101 is the upper side one hand connected fixedly to the supporting element 5 and on the other hand, the lower side fixed to the load-receiving means 7th The second portion 102 is formed in this embodiment as a hand lever with the means 15 for providing the force-dependent signal P - connected - also a particular inductive, transducers. The transducer is located inside of the first part 101 and provides a signal P for a in Fig. 5 unspecified, modifiable by the force applied to the hand lever manipulation force F distance between the two main parts 101, 102. For the motion control of the handling device 10 a fixed on the first part 101 mounted handle 114 is provided.

This sensor arrangement and selection of the handling device 10 is for both versions (5 Fig. 4,) a high-precision detection of the manipulation force F possible. Both versions of the handling device 10, both in combination mi an electric motor as well be used with a fluid drive. 2

An inventive system with an aforementioned second drive variant - a fluidically acting actuator 2 - is shown in analogy to Figure 2 in Fig. 6.. Again, the lifting unit 3 has a casing 3a, in which the drum 6 for winding up the rope (support member 5) and as a fluidically acting drive 2 in the simplest case, a pneumatic cylinder may be located. In the drawing, however, another, known per se pneumatic drive 2 is indicated. Such a drive 2 may for example consist of a laterally closed cylinder jacket and therebetween built ballscrew. By the ball screw, a - resulting in exposing a located inside the barrel piston with compressed air - translational motion are converted into a rotational movement for driving the drum. 6 The device 11 for generating the path-dependent signal S is an incremental Drehwinkelmeßscheibe (encoder), which is preferably coaxial with the drum 6 or in this embodiment - may be on a pulley 6a arranged for the support element 5 - as illustrated. The path-dependent signal S thus corresponds to a rotation angle α of the drum 6. For an inventive system with a fluidically acting drive 2 may - as the graphic representation shows - another safety device can be provided. This is a fluidic, in particular pneumatic, acting brake 20 for the flexible support element 5, in particular for a rope.

The brake 20 is shown in Fig. 9 as an individual part. It has a cylinder-shaped housing 21 with a housing 21 on the upper side cover closing 22 and a housing 21 under mutually occluding footplate 23. In the housing 21, a piston 24 longitudinally movable out of the 21 divides the housing into a sealed pressure chamber 25 for a pressure-generating fluid and in a spring chamber 26th Lid 22, base plate 23 and piston 24 each have a unspecified through opening for the support element. 5 In the spring chamber 26 are around the supporting element 5 at least two locking elements 27, in particular balls, are arranged in the illustrated embodiment. The locking elements 27 are acted upon on one side by springs 28 and on the other hand, by the pressure under the action of the fluid piston 24th The spring chamber 26 has a such in the direction of the piston 24 tapering section 29 that the locking elements 27 when they are looking at existing pressure action of the fluid in a spring-side of this area 29, releasing the supporting element 5, and when in the absence of pressure effect the fluid under the action of the springs 28 are moved in a piston-side part of the area 29, the supporting element 5 jamming in the housing 21st This safety device a crash load can be prevented in case of failure 9 of the working pressure of the fluid.

A serious disadvantage of fluidic actuators 2 consists in the risks that assume when a load 9 suddenly triggers undesired operation of the load handling device. 7 Due to the sudden absence of the load 9 there is an explosive reaction in the drive 2, wherein the support member 5 is pulled upward. The brake 20 described can be also advantageously used to prevent such situations safety. The brake 20 can thereto in an installed position in the lifting unit 3 can be fitted, which is rotated with respect to the installed position in Figs. 6 and 7 by 180 °. The distance-dependent signal S a substantially vertical ZZ movement - in this case, upward movement - corresponds to the support element 5, can then additionally be used as input signal for control of the brake 20, namely for opening a pressure relief valve for the pressure chamber 25th A sudden upward movement of the support element 5 can be prevented, wherein in the brake 20, a counter force is produced to force the fluidic drive 2, which prevents a destruction of the drive 2 and the occurrence of impending danger situations. A brake 20 may be advantageously combined in the rotated position of 180 ° with a brake 20 in the installed position shown in FIGS. 6 and 7.

In particular, the presence of a fluidically acting drive device for can advantageously be provided to power the control loop for load balancing, the control for the vertical ZZ movement of the support element 5, the safety control system (s) and / or the programmable logic controller PLC one in particular replaceable battery. A mains power supply is then not necessary. Such a battery can for example be arranged on or in the handling device 10, so that it can be easily removed from the system and reconnected to a recharging.

The supporting element 5 can - in contrast to the embodiments described - be rigid, for example, a rack or the like, is formed. If such a rack is to be used, for triggering the movement of a corresponding sprocket can drive the 2 for tooth be provided intervened in the bar. The device 11 for generating the path-dependent signal S can then be designed so that can be detected a substantially vertical ZZ movement of such rod. This can include sensors are used to provide the path-dependent signal S, is directly detected by a linear path of the supporting element. 5

In another way a rigid training of the support element has been initially pointed. Such, the known from DE 4342715 AI manipulator similar arrangement may - compare Fig. 8 - also be formed such that the supporting element 5 comprises a Tragparallelogramm, are connected in the portion of arms 30 in joints 31 having a horizontal pivot axis together, the angular position and the lengths of the arms 30 of Tragparallelogramms within a vertical plane are lying changeable (shown in dashed lines). In such an arrangement, the path-dependent signal S may also correspond to an angle of rotation, namely an angle in order to move two via a joint 31 interconnected partial arms 30 of Tragparallelogramms to today. The device 11 for generating the path-dependent signal S can then be an incremental Drehwinkelmeßscheibe, arranged coaxially to the pivot axis of the joints with advantage again. In the shown in FIG. 8 system is again a system with fluidic drive 2 (pneumatic or hydraulic cylinders). For such a system, the means 11 for generating the path-dependent signal S can also be arranged on the piston rod sensors for linear position detection. The load receiving means 10 is simple example here formed by a lifting hook. From the foregoing it can already be seen that the present invention is not limited to the embodiments shown, but all have the same effect for the purposes of the invention means and measures shall include, not described herein embodiments of drive 2. For example, as a drive 2, a combination a linear-acting fluid piston-cylinder assembly with a built after the manner of a pulley roller assembly for moving deflection possible with an incremental Drehwinkelmeßscheibe may be arranged as a device 11 for generating the path-dependent signal S coaxially to the rollers.

As sensors for detecting the manipulation force F or for the provision of the travel-dependent signal S other than the sensors described herein can be used.

Furthermore, the skilled worker are given multiple opportunities to further embodiment of the invention. So the load lifting device 1 for its movement in the horizontal direction XX and / or YY can also be associated with at least one drive means in response to a - from which gravity at rest selbstätig adjusting vertical orientation ZZ - forced displacement of the support element 5 is controlled and this has a special control system. In this regard, 297 19 865 Ul reference in its entirety to the aforementioned German utility model DE.

Furthermore, the invention is not limited to the combination of features defined in claim 1, but may also be any other combination of specific Features of all the individual features disclosed be defined. This means that in principle virtually any individual feature of claim 1 is omitted or can be replaced with at least one disclosed elsewhere in the application single feature. Extent, claim 1 is to be understood merely as a first attempt at formulating an invention.