LOADING DEVICE

Abstract: A device controlled by automatics for handling material, for example scrapped goods, waste paper and paper bales, comprises an elongated arm (1, 2, 3) with one or several parts mutually connected, for example pivotably. A gripping apparatus (8) is arranged on the arm and at least one sensor (12) is arranged to sense whether any material exists on a ground portion or not. Furthermore, a control unit (15) is arranged to control the movement of the arm to the material on the basis of information received from said sensor (12). In this device the sensors (12) are arranged on the arm of the device and the control unit is adapted to control the arm to sweep over the ground, preferable at a substantial height over the material, so as to position the material. The sensors (12) have transmitter as well as receiver of signals of intermittent or continuous nature, the latter being intended to be reflected by the material or the ground, so as to measure the distance to the ground and by doing so position the material.

Description: Loading device FIELD OF THE INVENTION AND PRIOR ART This invention relates to a device controlled by auto¬ matics for handling material, for example scrapped goods, waste paper and paper bales, according to the preamble of claim 1. Such a device is generally used for picking up material from a place and unload it on another place not far away. It can be a question of transporting material lying in a heap of metal scrap formed by unloading of lorries, to a container leading to a scrap press. The gripping apparatus can in such a case comprise a strong magnet as an alternative to gripping prongs. Besides moving waste products, which also comprise paper and other thing and material existing in disorded heaps, a device of this kind may also be adapted to handle material stored up more arranged, as for example paper bales, tube bundle and the like. In fact, a device of this type can be adap¬ ted to lift all kind of load imaginable from one place and let it down on a place not far away. These devices were earlier commanded by an operator which was close to the device and could ' recognize where mate¬ rial intended to be moved was located by means of his eye and then could control the arm of the device having the gripping apparatus to the material. In the meanwhile said operator has become unnecessary as a consequence of rationalization and he has been replaced by an elect¬ ronic control unit, which controls the complete loading process by delivering signals to the means taking care of the movement of the device. When the operator with his eyes is removed from the place of work of the loading device, the problem arise to locat the load lying on the ground and waiting for transport. One type of devices has solved this problem by programmin the control unit to divide the ground on which the mate¬ rial could be located in a number of small squares and then control the armhaving the gripping apparatus so that the gripping apparatus is lowered and grasps for load in one square after the other - irrespectively of whether load is lying on the ground square in question or not. This procedure is continued until the whole load area has been scanned and is repeated if there possibly is more material within one single square than the gripping apparatus on the same time can grip. It is obvious that although the costs for the operator are saved great losse of time are caused by a device operating in such an uneff cient manner. Of course efforts have been made in order to improve a device of this type. These efforts have lead to that type of devices which corresponds to the preamble of claim 1 and constitutes the prior art on the field of the invention, namely the kind of devices which have one or more sensors for sensing load on the ground. These sensors deliver signals to the control unit which on the basis of these controls the movement of the arm to the load. In these devices photocells are used to locate the load. The transmitter and the receiver of these photo cells are arranged on two opposite walls arranged on each side of the loading area. Thanks to that a photo¬ cell which beam is interrupted by load is able to inform the control unit about this fact, which thereupon in its turn controls the gripping apparatus to the load. This type of device operates somewhat quicker than the one previously mentioned, but has nevertheless a func¬ tion unsatisfying on several points. In the first place at least two walls have always to be set-up and brought into alignment with each other before the.loading can start, or if the sensors are installed in stationary walls the device is tied up to one and the same work place. In the case that the loading device is mobile and has to move over a great area while searching for load, it will hardly be possible to set-up such walls around the whole area, probably leading to the necessity of an operator in such a case. However, the main drawback of this device is the unsufficient speed thereof. Since a photocell, the beam of which is interrupted, solely is able to inform the control unit of the existence of material somewhere between the transmitter and the receiv of the photocell, a control unit is forced to first of all control the arm and the gripping apparatus to move for instance to said transmitter and after that control the same to move generally parallel to said beam and in the direction of the wall on which the receiver is arranged, until the gripping apparatus hits some load. This will require a considerable time and it can further cause tipping of material stored up in a certain direc¬ tion and by that to subsequently more complicate handling. SUMMARY OF THE INVENTION The object of the present invention is to reduce the drawbacks mentioned above of the device according to above to a large extent. According to the invention this object is obtained by providing a loading device of the type discussed above with the characteristics defined in the characterizing part of claim 1. By locating the sensors on the arm of the loading device and providing them with transmitter as well as a receiver of signals of intermittent or conti nuous nature, it is possible to make it without the afore said walls. Since the sensors locate the load by mea¬ suring the distance to the object by which the signals are reflected, t * he arm will be able to sweep over the ground at a substantial height without any risk of tip¬ ping load possibly arranged. Furthermore, the device according to the invention operates more rationally and considerably faster than the devices previously known. In the operation of the device the arm sweeps from a boarder of the loading area and into and over it. As soon as a sensor "finds" load on the ground portion which it is sensing in that very moment a signal is sent to the control unit, which controls the gripping apparatus to first of all go to a location directly above the indicated load, be lowered, grip and then transport the load to an unloading place arranged therefor. After that the sweeping movement is started again from the border of the load area or possibly from the border where the load recently has been sensed, and in this way the loadin device is working towards the opposite load border while picking up the entire load located on the ground. By this the arm does not have to move unnecessary long ways while searching for load, which accordingly leads to a considerable saving of time. In a preferred embodiment the sensors are constituted by transmitter and receiver of ultrasound, thus getting a totally new field of application. Other characteristics and advantages of the device according to the invention will appear from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a specific description of an example of a preferred embo¬ diment according to the invention. In the drawings: Fig 1 is a schematic, perspective view of a preferred embodiment of the loading device according to the inven¬ tion, in which details has been omitted, fig 2 is a schematic, perspective view of the loading device according to fig 1 in a state where it is searchin for load,. fig 3 is a view corresponding to fig 2 of the loading device in a state where it is gripping the load found, and fig 4 is a block diagram illustrating the way of function of the device according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION In the following the word crane is used instead of loadin device for the sake of simplicity, but this should not be understood as any limitation of the invention. In fig 1 a crane having three elongated arm parts 1 , 2 and 3 is illustrated. The arm parts are pivotably con¬ nected to each other by hinges 4 and 5 about axes, which are generally parallel to each other and generally per¬ pendicular to the extension directions of the arm parts. The arm part 1 is at point 6 arranged upon a cube 7 in order to raise the operating height of the crane. The attachment of the arm part 1 on the cube is through a turning motor turnable about an axis directed generally perpendicularly to the ground. This rotational movement is illustrated by the dashed line representations of the crane according to the invention. The extrimity of the outermost arm part 3 is provided with a gripping apparatus 8 having prongs 9 for gripping material. Furthermore, the crane has piston cylinders 10, 11 controlled by pressure fluid and taking care of the pivoting movement of the arm parts relative to each other. A piston cylinder mechanism 13 (fig 3) affect the location of the prongs of the gripping apparatus. On- and along the arm part 3 sensors 12 consisting of ultrasound detectors are arranged. These sensors are so orientated that they are sending out ultrasound toward a surface portion (see fig 2) of the ground of their own, when the arm part extends aproximately parallel to a ground plane. These surface portions are located essentially on a line along the projections of the arm parts on the ground while overlapping each other slightly The ultrasound transmitted by the sensors is reflected by the ground or material thereon and detected by recei¬ vers of the sensors. A control unit 15, not shown, constituted by a suitable computer, is placed in connection to the crane and is connected to a power supply of the movement device, to a piston cylinder 13 of the gripping apparatus and the sensors 12 by means of electric cables, said movement device being constituted by the turning motor and the piston cylinders 10, 11 previously mentioned. For the sake of simplicity these cables as well as the pressure fluid ducts to the cylinders have been omitted in the figures. Close to the piston cylinder 10 a detector 16 (not shown) is arranged, this detector detects the pressure necessary in the fluid duct to this cylinder to compensate the lever forces with respect to the hinge 4 generated by the weight of the arm. This detector delivers informa¬ tion about said pressure to the control unit over an electrical cable. Now the function of the crane according to the inven¬ tion is to be explained with reference made to the figure 2 and 3, at the same time as figures 4 should be reachabl in order to follow the way of the different signals for the control of the crane. When the crane starts to search for material it will perhaps arrive from an unloading place. The control unit does first of all control the turning motor, so that the crane arrives to the outer edge of the area where material can be expected to lie on the ground, and after that it controls the different piston cylinders so that the crane, in the case of "folded together"-arm parts 1, 2, 3, assumes the location according to fig 2, in which the arm part 3 extends substantially parallel to the ground. Now the sensors 12 are turned on by a signal from the control unit, whereupon they start to transmit and receive reflected ultrasound. In an embodiment five sensors are arranged on the arm part^-3 and adjacent senso have an orientation differing by about 11°. If the arm part 3 in the location according to fig 2 is located about 5- eters above the ground and each sensor senses a surface having a diameter of about 1 meter, a continous sensed area is formed, in which the surfaces sensed by two adjacent sensors overlap each other slightly. These surfaces are shown through dashed lines in fig 2. The control unit does now deliver a signal to the turning motor causing it to continue the turning of the crane arm into the space above the ground to be searched. Durin this turning the sensors 12 are continously measuring the distance to the ground and the measurement results are lead to the control unit. When suddenly one of the sensed surfaces through its outermost border enters into the space above a ground portion covered by material 14, the sensor in question indicates a shorter distance to the ground than before. This distance is reported to the control unit which after a period of time, the length of which is depending on the turning speed of the arm and the distance between the turning center of the crane and the material detected, for instance 0,3 seconds, sends the signals to the turning motor which stops. The extension of the arm should now be generally directly above the material indicated. In fig 2 the centrally situated sensor 12' will first indicate materia 14 on the ground. The control unit does now send signals to the power supply for the piston cylinders effecting the movement of the arm parts. These move so that the gripping apparatus 8 arrives directly above the surface on which material have been found, whereupon the control unit continues to control said power supply through signals, so that the gripping apparatus is lowered toward the material in an opened state. The control unit is arranged to, in the case that two adjacent sensors are sensing material within said period of time, control the arm so that gripping apparatus is lowered half-way between the two surfaces sensed by these sensors. When the gripping apparatus hits material and the weight of the arm begins to rest upon this material, the pressure in the piston cylinder 10 is reduced. The detector detec¬ ting the pressure in the fluid duct to this cylinder sends a signal to the control unit when the pressure falls below a certain value which corresponds to the fact that the gripping apparatus is resting on the mate¬ rial. This information causes the control unit to control the gripping apparatus over its power supply, so that it grips the material by the prongs 9 (see fig 3). After that the control unit controls the moving device of the crane so that the gripping apparatus with the gripped material is transported to the place for unloading the material, for example a scrap press. After that the cycle described is repeated until the entire material has been carried to the unloading place. The control unit stops the sinking of the gripping appa¬ ratus at a predetermined height over the ground, provi¬ ding that comparatively little material is lying there, so that the ground is not damaged by the gripping appara¬ tus. In an embodiment of the invention detectors 17, which by detecting the pressure in the fluid duct to the piston cylinder mechanism 13 causing the gripping about and the holding of the material by the prongs 9, are arranged in the gripping apparatus to deliver signals depending on the weight of the gripped material to the control unit, which on the basis of the nature of said signals controls the gripping apparatus, either to move to the unloading place or to rise to the lcoation accor¬ ding to fig 2 so as to continue searching for load. Of course the letting down of the gripping apparatus follo¬ wing thereupon has to take place with the latter closed and it has to be controlled to open for the first time when it hits material. Thus, the last mentioned detectors makes the crane according to the invention even more efficient, because it does never arrive to the unloading place with the gripping apparatus half-empty. It is possible to arrange additional sensors, which are turned on by the control unit during the lowering of the gripping apparatus towards the material, so as to achieve a fine location of the material and cause the control unit to carry out a fine correction of the moveme of the gripping apparatus through signals to the control unit. Such additional sensors could for, instance be arranged on the gripping apparatus itself. The invention is not limited to the above mentioned, but several possibilities to modify the loading device according to the invention would probably be obvious to a man skilled in the art without diverging from the idea of the invention. For instance the arm parts can principally be as many as desired or only one single, which is displacable in a beam, and/or maybe telescopically variable in length. The arm part having the sensors may during the searching for material be considerably inclined with respect to the ground, and the sensors may be orientated in accor¬ dance therewith. The loading device can be arranged on a freely movable carriage or one running on a track, in which the translation movement of the carriage may replace the rotational movement obtained by the turning motor. The gripping apparatus can have an arbitrary form. If load has been stored on the ground in a certain direc¬ tion, the control unit can be arranged to control the orientation of the gripping apparatus according thereto, in which the gripping apparatus may have gripping means which grip the load solely from two opposite directions or from an arbitrary number of directions. All kinds of tubes and cylinders are examples of load to be gripped from two directions. The number of sensors on the arm parts can be very great in order to achieve a high accura of the locating of the load, or even less sensors than described above may be arranged. Furthermore, they may be located on different arm parts. If three sensors are indicating load within the period of time mentioned above the control unit may be adapted to control the gripping apparatus to a surface sensed by the intermediate sensor and so on. Preferably, a. control unit is programmed so that it stops the turning motor during the searching for material providing that one sensor detect a reduction of the distance to the ground corresponding to a very small quantity of material. Although, the sensors in the embodiment here described transmit and receive signals in form of ultrasound, it will be possible to employ sensors which operate (trans¬ mit as well as receive) with other types of signals. The loading device according to the invention is not restricted to the application field mentioned above, but it may through suitable modifications be used under all circumstances where objects occur on a surface on different places, and these objects have to be moved to a place not far away.

Claims: Claims 1. A device controlled by automatics for colleting dis¬ arranged material, for example scrapped goods, waste paper and paper bales, occurring within a certain area and moving it to one or more predetermined points or places, comprising an elongated arm (1, 2, 3) with one or several parts mutually connected, for example pivotabl a gripping apparatus (8) being arranged on said arm, at least one sensor (12) being arranged to sense if any material exists on a ground portion, and a control unit (15) being arranged to control the movement of the arm to the material on the basis of information received from said sensors (12), said sensors (12) being arranged on the arm (1, 2, 3) of the device, the control unit (15) being adapted to control the arm to move over the ground, preferably at a substantial height over the mate¬ rial, so as to locate the material, said sensors (12) having transmitter as well as receiver of signals of intermittent or continous nature, the latter being inten¬ ded to be reflected by the material or the ground, so as to measure the distance to the material or the ground, respectively, and by doing so locate the material, c h a r a c t e r i z e d in that the control unit (15) is adapted to control the movement of the arm during the searching for material in such a way, that the arm parts (1, 2, 3) are having a fixed mutual position and a sweeping movement over the area to be scanned is carrie out by the whole arm, and that the location of the sensor (12) on the arm is so as to permit them to jointly sense a generally continous portion of said ground, said portio extending in the extension direction of the arm and pre¬ ferably corresponding to at least the entire reach of the arm. 2. A device according to claim 1, c h a r a c t e r i¬ z e d in that the sensors (12) are arranged on the same arm part (3), that the control unit (15) is adapted to control the sweeping movements of the arm so that this arm part (3) is held generally parallel to the ground, and that the sensors (12) are so directed that the surfac to be sensed by a sensor is slightly overlapped by the surfaces to be sensed by the adjacent sensors on each side in the extension direction of the arm. 3. A device according to claim 2, c h a r a c t e r i- z e d in that the control unit (15) is adapted to contro the arm parts (3) having the sensors (12) to move compa¬ ratively far above the ground while searching for materia and that the sensors (12) are arranged comparatively close to each other on the arm part (3). 4. A device according to any of claim 1 to 3, in which the control unit (15) is adapted to, upon receiving infor mation from a sensor (12, 12') about the existence of material on the ground, affect the arm to lead its grippi apparatus (8) over the ground portion sensed by the senso in question and lower the gripping apparatus until it is resting on the material, c h a r a c t e r i z e d in that a sensor (16) is arranged to indicate that the gripping apparatus (8) is resting on the material by sensing the power to be supplied to a power unit (10) holding the arm, so as to transmit a signal to the contro unit, which is adapted to by means thereof control the gripping apparatus to grip the material. 5. A device according to any of the preceeding claims, c h a r a c t e r i z e d in that the gripping apparatus (8) is provided with load weight sensors (17) arranged to transmit signals to the control unit, the nature of said signals depending on the weight of the load gripped by the gripping apparatus, and that the control unit is arranged to, on the basis of the nature of the signals control the arm having the gripping apparatus either to a movement to a place for unloading or to an elevation of the apparatus (8) to a position for conti¬ nued searching for material by sweeping. 6. A device according to any of the preceeding claims, c h a r a c t e r i z e d in that the control unit is arranged to control the arm to continue its sweeping movement during a certain period of time after a sensor (12, 12') has discovered material on the ground, the length of said period of time depending on the sweeping speed and the distance of the indicated material from the fixed point (6) of the arm, so as to affect the ex¬ tension of the arm to arrive directly above the material indicated. 7. A device according to claim 6, c h a r a c t e r i¬ z e d in that the control unit is arranged to, when a further, adjacent sensor senses material within said period of time, control the arm so that the gripping apparatus (8) is lowered half-way between the two surfaces sensed by these sensors.

Inventors: FROEDERBERG PER-ARNE, FROEDERBERG, PER-ARNE
Applicants: FROEDERBERG PER ARNE, FROEDERBERG, PER-ARNE
Application year: 1986
Main classification: B25J19
IPC codes: B25J9, B25J15, B25J19, B66C13