Abstract:
A large manipulator, especially for self-propelled concrete pumps includes a rotary head that rotates about a vertical axis on a mast stand, and a jointed or articulated mast composed of at least three mast arms. The mast arms of the jointed mast can be swivelled to a limited extent about horizontal, mutually parallel axes relative to the adjoining rotary head or mast arm using a corresponding drive unit in each case. The jointed mast is operated by a remote control device which has a signal transmitter situated at the mast top and a control unit. The signal transmitter drives a computerized coordinate field device actuating the drive units according to a displacement path relative to the momentary position of the mast top as directly indicated by means of the control unit.

Description:
FIELD OF THE INVENTION 
     The invention relates to a large manipulator, especially for self-propelled concrete pumps, having a rotary head rotatable about an essentially vertical axis of rotation by means of a driving system and arranged on a frame, especially a chassis; a jointed mast composed of at least three mast arms and preferably designed as a concrete-distributing mast, which mast arms are pivotally limited about horizontal, mutually parallel joint axes relative to the respectively adjacent rotary head or mast arm by means of a further driving system. The further driving system has a remote-control device. The remote-control device has a control member for controlling the driving system and for adjusting the mast top, which preferably carries an end hose, along a displacement path. The invention relates further to a method for operating the large manipulator. 
     BACKGROUND OF THE INVENTION 
     Self-propelled concrete pumps of this type are mobile tools, which with a full 360° swivelling range of the rotary head can also be utilized when the jointed mast is in an extended horizontal position. The operator is responsible for the control of the self-propelled concrete pump and the positioning of the concrete end hose on the last arm of the jointed mast. He must operate more than three rotatoric degrees of freedom of the jointed mast through the associated driving systems while moving the jointed mast in a non-structured three-dimensional work space, while closely monitoring the building-site border conditions. By using proportional-radio telecontrols this operation was made easier since the operator is no longer encumbered with a cable attached to the self-propelled concrete pump. However, the risk that during a single-axis operation uncontrolled movement at the end hose continues, thusly endangering the building-site personnel. Furthermore, a quick correctional movement of the end hose requires a simultaneous control of several axes. In the past, a single control was required for each of the rotatoric degrees of freedom of the jointed mast. It has already been suggested in order to ease the handling of the large manipulator, to move the end hose through a suitable calculator support in a cartesian x-, y-, z-coordinate system with the help of switch levers, whereby a frame-fixed or building-site-fixed coordinate system can be selected. (&#34;Computer controlled concrete distribution&#34;, Dr.-Ing. Hartmut Benckert, Putzmeister-Werk, Seiten 111-119, 8th Int. Symposium on automation and robotics, IPA (FHG) Stuttgart 1991). However, this type of operation has not proven to be rationally sufficient for many uses since the operation of the switch levers needed for this cannot always be precisely synchronized with the optically recognizable sequences of movement of the jointed mast. 
     Starting out from this the basic purpose of the invention is to improve the conventional large manipulator of the above-disclosed type in such a manner that it is possible for the operator to control any desired points within the area of the reach of the jointed mast by simple manipulations directly from the concrete-feeding point. 
     SUMMARY OF THE INVENTION 
     The basic thinking for the solution of the invention is that the operator easily directs the end hose manually toward the concrete-feeding point and that the mast top automatically follows it. A suitable signal-transmitting path is needed for this, with which the mast top can be moved by the operator with a computer assistance over a displacement path preferably specified by the end hose. In order to achieve this, the invention provides that the remote-control device has a signal transmitter, which is arranged at the mast top and can be mechanically, optically, electromagnetically or electrically released through the control member, for controlling a computer-assisted coordinate transmitter, which operates the driving systems of the jointed axes and axes of rotation in accordance with a displacement path directly indicated by means of the control member relative to the instantaneous position of the mast top. 
     According to a preferred development of the invention, the control member is designed as a control lever, which is mechanically connected to the signal transmitter and is adjustable relative to the mast top in various directions indicating the displacement path, and which control lever can be operated, for example, through a sensor ring, a rope or a rod, and can also be mechanically connected to the movable end hose and grips around same with a certain play. 
     As an alternative to this it is possible that the control member and the signal transmitter are connected with one another by a direction-sensitive wireless transceiver path, for example by a light, infrared or radio path, whereby a transmitter provided in the hand or on the helmet of the operator can be used as the control member. A signal emitted by this transmitter in an upward direction, preferably in the form of a narrow directional cone, can be received by the direction-sensitive receiver arranged in the area of the mast top and can be converted through a suitable evaluating electronics and the coordinate transmitter into the desired movement of the jointed mast. For this purpose, the transmitter can also contain a Laser diode and the receiver a direction-sensitive light receiver. 
     A preferred development of the invention provides that the control member is designed as a direction-sensitive inclination indicator, which is preferably releasably and/or elevationally adjustably arranged on the movable end hose. The direction sensitivity can become reality, for example, through the use of a biaxial inclination indicator. The inclination indicator has evaluating electronics with an integrated or following signal transmitter for emitting a displacement-path signal depending on the measured direction of the inclination and/or a speed signal depending on the measured angle of inclination for the movement of the mast top. The inclination indicator preferably together with the signal transmitter can be arranged in a housing, which can be fixedly fastened against rotation relative to the mast top on the end hose. Based on this measure, it is possible to move the mast top during the deflection of the end hose into a direction corresponding with the direction of deflection with a speed dependent on the deflection or inclination angle. 
     The large manipulator can be particularly easily handled with the inclination indicator of the invention when a handle is provided on the end hose. The handle is arranged pivotally about the hose axis and/or about an axis extending transversely with respect to the hose axis. The handle has for handling by both hands, advantageously, two handle parts projecting toward diametrically opposite sides of the end hose. The handle is suited additionally for mounting of switch or control elements, for example, for switching the concrete pump on or off and/or adjusting the amount to be transported and/or for lifting and lowering the mast top. In order to avoid an unintended movement of the mast top, it is possible to design in addition one of the switch elements as a dead-man switch. 
     The driving systems of the jointed mast and of the mast base are, for reasons of safety of operation, combined and controlled through the coordinate transmitter, while advantageously maintaining the height of the mast top in a specified horizontal plane. The improvement here is that the mast top follows the signal transmitter in such a manner that it always remains approximately vertical at a certain elevational distance above the operator and follows at a specified minimum deflection of the end hose of, for example, ±50 cm. To adjust the height of the mast top, it is possible to additionally provide a manually operated elevation-adjusting element. The elevation-adjusting element can have, for example, a speed-controlled double-throw switch with a defined zero position, which switch reacts to a lifting and lowering force engaging the control member. 
     It is particularly advantageous when the speed of movement of the mast top can be controlled in accordance with the deflection range of the control member in a displacement direction relative to a zero position. 
     To optimize the sequence of movement during the horizontal and/or vertical adjustment, it is important that the driving systems of the redundant joint axes of the jointed mast can be operated in accordance with a selected predetermined path-swivel characteristic. Since the mast arms depending on their alignment relative to the gravitation axis, on the one hand, and on the load engaging said arms (for example concrete in the feed pipe), on the other hand, are subjected to more or less great bending and torsion loads, which loads adulterate the position of the mast top at specified swivel positions in the individual joints, it is suggested according to a preferred development of the invention, that the path-swivel characteristic in the coordinate transmitter be modified in accordance with the load-dependent bending and torsion moments engaging the individual mast arms. The same applies when, in order to avoid collisions in the moving space of the jointed mast, obstacles must be overcome. It is here advantageous to modify the swivel path characteristic of the joint axes in the coordinate transmitter in accordance with collision zones spatially limiting the mast-arm movements, in particular by indicating a highest and/or lowest bending point. A further security in this respect is achieved when the swivel path characteristic of the joint axes in the coordinate transmitter can be modified in accordance with measuring signals emitted by a distance sensor, preferably arranged on the last mast arm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be discussed in greater detail hereinafter in connection with exemplary embodiments schematically illustrated in the drawings, in which: 
     FIG. 1 is a side view of a self-propelled concrete pump with a five-arm jointed mast in a collapsed state; 
     FIGS. 2a and b are a side view and a top view of a self-propelled concrete pump with an extended jointed mast; 
     FIG. 3 shows a section of the jointed mast according to FIG. 2a with a mechanically operated remote-control device arranged at the top of the mast; 
     FIG. 4 shows a section corresponding to FIG. 3 with a wirelessly operated remote-control device; 
     FIG. 5 shows a section corresponding to FIG. 3 with a rope-operated remote-control device; 
     FIG. 6 shows a section of the jointed mast according to FIG. 2a with an inclination indicator arranged at the end hose and a handle; 
     FIGS. 7a to c are three side views of the mast top with an end-hose section without deflection, with deflection to the left or right and with deflection forward and backward and; 
     FIGS. 8a to c are three side views of the lower end of the end hose with a handle. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The self-propelled concrete pump illustrated in the drawings has a chassis 10, a mast base 16 arranged near the front axle 12 and the cab 14 of the chassis 10, a rotary head 17, which is rotatable at 360° on the mast base 16 about a vertical axis 18 by means of a hydraulic rotating system and carries a jointed mast 20, a hydraulically driven concrete pump 24, which can be loaded with concrete through a material-feeding container 22, and a conveyor pipeline 28 connected to the concrete pump 24 through a pipe switch 26. The jointed mast 20 has five mast arms 1, 2, 3, 4 and 5, which are pivotally connected with one another at the joint A to the rotary head 17 and at the joints B, C, D and E about each horizontal jointed axes. The collapsing and extending of the mast arms 1 to 5 about the joints A to E is done hydraulically by means of double-acting hydrocylinders 30, which are hinged with their free cylinder-side and rod-side ends to booms or holding bars of the mast arms 1 to 5 and of the rotary head 17. The mast arms are in the travelling position shown in FIG. 1 collapsed against one another in an essentially parallel alignment, whereas they are extended in the illustration according to FIGS. 2a and b. 
     A remote-control device is provided for operating the driving systems 30 of the jointed mast 20, which device includes a signal transmitter 53 and a vehicle-fixed central control 31, which communicates galvanically or wirelessly with the signal transmitter 53. A control member 52, 54 is provided to adjust the top of the mast 55 and the end hose 50. The control member 52, 54 is mechanically connected to or communicates wirelessly with the signal transmitter 53, and is moved by the operator 51 directly over the desired displacement path of the mast top 55. 
     The control member 52 is, in the exemplary embodiment illustrated in FIG. 3, designed as a sensor ring mechanically connected through a plastic rod 60 to the signal transmitter 53 arranged at the mast top 55 and surrounding the end hose 50 with clearance. The signal transmitter 53 is thereby designed advantageously as an analogue-proportionally operating cardanic angle indicator, which is connected to the central control device 31 through a control cable 62. A vertically movable, analogue-proportionally operating tumble switch 63 is arranged in the lower area of the plastic rod 60 in the illustrated exemplary embodiment. The switch 63 can trigger a vertical adjustment of the mast top 55. The elevation-adjusting switch 63 can also be arranged at the upper end of the plastic rod 60 and can be operated by lifting and lowering of the plastic rod. This arrangement is subjected to little danger of damage during rough building-site operations. 
     In addition, it is possible to arrange a switch 64 on the sensor ring 52 for turning the concrete pump on and off and for controlling the amount to be transported. 
     The exemplary embodiment illustrated in FIG. 4 provides a wireless, direction-sensitive signal-transmitting path, for example, a Laser-light or infrared path, between the control member 54 and the signal transmitter 53. For this path, the control member 54 is designed as a transmitter for use in the hand or on the helmet of the operator 51. The transmitter emits a narrow, upwardly pointing directional cone 55 with a varying intensity distribution, which can be evaluated through the receiver 53 and the control device 31 for adjusting the mast top 55. Also the jointed mast 20 follows, with its mast top 55, a movement of the operator 51 parallel to the horizontal plane 40. 
     The exemplary embodiment according to FIG. 5 shows the operator 51 mechanically connected through a rope 65, which is fastened to his helmet 52 or to his body, to the signal transmitter 53 designed as a cardanic angle indicator. The force applied by the movement of the operator 51 through the rope 65 is evaluated according to direction and pull through the signal transmitter 53 and the central control device 31, such that the jointed mast 20 follows with its mast top 55 a movement of the operator parallel to the plane 40. 
     The additional introduction of a vertical movement is possible both at a mechanical or a wireless signal transmission from the concrete-pouring point through a hand-operated elevation-adjusting element 63. Accordingly, it is also possible to turn the concrete pump on and off from the pouring point with a switch intended therefor. 
     Corresponding control signals are transmitted to the control device 31 through the signal transmitter 53, when the control member 52 is deflected in the desired direction of movement. The control signals are converted in a data-processing step and by a computer-assisted coordinate transmitter into coordinate signals for the driving systems 30 of the six axes 18, A, B, C, D, E. In addition, it is possible to convert the magnitude of the deflection of the control member 52, 54 through a suitable sensoric or electronic conversion into speed-determining signals. All six axes are controlled with software within the coordinate transmitter in such a manner that the respective joints move harmonically with one another in dependency of the path and time. The control of the redundant degrees of freedom of the joints is done according to a preprogrammed strategy, into which can also be fed collision zones in the form of obstacles, ceilings, built-ins and the like, through the operation software and can be considered in the sequence of movement. 
     The control member 52 is in the exemplary embodiment illustrated in FIGS. 6 to 8 designed as an inclination indicator. It exists together with the signal transmitter 53 in a small housing, which can be fastened with a bracket 70 fixed against rotation to the end hose 50. The control signals emitted by the inclination indicator 52, 53 are fed through the control cable 62 to the central control 31. The inclination indicator 52, which is designed with two axes, is direction-sensitive. It responds to both lateral deflections of the end hose corresponding to FIG. 7b and also to deflections perpendicular thereto corresponding to FIG. 7c, and is therefore suited together with the signal transmitter to emit a displacement-path signal dependent on the measured inclination direction. Furthermore, a speed signal dependent on the measured angle of inclination can be produced for moving the mast top 55. 
     A handle 72 is releasably fastened in the lower part of the end hose 50 by means of a snap bracket 74. The handle 72 consists of two handle parts 72&#39;, 72&#34; projecting over the end hose towards diametrically opposed sides. The handle is arranged rotatably at approximately 340° about the end-hose axis so that it can be accessed easily from all sides. If need be, it is also possible to pivot the handle 72 about the axis 76, which extends transversely with respect to the end-hose axis. The handle can additionally be equipped with some switch and control members, for example, a switch 78 to turn the concrete pump on and off, two key elements 80 to adjust the amount to be transported in a positive or negative direction, an elevation-adjusting member 82 designed as an adjusting lever for the end hose 50, and a dead-man switch 84 as a safety measure. 
     The described process is good for concrete work on precisely structured building sites, in particular, when apparati with a great reach is used. 
     In conclusion the following is to be stated: The invention relates to a large manipulator, in particular for self-propelled concrete pumps. A rotary head 17 rotatable about a vertical axis of rotation on a mast base 16 and a jointed mast 20 composed of at least three mast arms 1-5 are arranged on a chassis 10. The mast arms 1-5 of the jointed mast 20 are pivotally limited about horizontal, mutually parallel joint axes A to E relative to the respectively adjacent rotary head 17 or mast arm 1-5 by means of the driving systems 30. The jointed mast 20 is operated by a remote-control device which has a signal transmitter 53 arranged at the mast top 55 and can be mechanically released through a control member 52, for controlling a computer-assisted coordinate transmitter, which operates the driving systems 30 of the joint axes and axes of rotation in accordance with a displacement path directly indicated by means of the control member 52 relative to the instantaneous position of the mast top 55. 
     Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.