ARRANGEMENT AND METHOD FOR CONTROLLING BOOM ACTUATING CYLINDERS IN ROCK DRILLING EQUIPMENT

Abstract: The invention relates to an arrangement and a method for controlling a boom in a rock drilling equipment, the boom (1) comprising several actuating devices (18a to 18d) connected in parallel to supply and return lines (16, 17) for hydraulic fluid in such a way that a selector valve (19a to 19d) is provided for each actuating device (18a to 18d) between the actuating device and the lines (16, 17); and a proportional valve (13) connected to the hydraulic lines (16, 17) for regulating the flow of hydraulic fluid. The invention further comprises a control unit (12) where separate set values are preset for each actuating device (18a to 18d) so that the speed of movement of each actuating device is proportional to the range of movement of the respective control member (11a to 11d).

Description: Arrangement and method for controlling boom actuating cylinders in rock drilling equipment The invention relates to an arrangement for controlling a boom in a rock drilling equipment, the boom comprising several actuating devices for its different operations; a selector valve for each actuating device; two lines for hydraulic fluid, to which the selector valves are connected in parallel, the selector valve of each actuating device connecting said lines for hydraulic fluid in communication with the respective actuating device when this actuating device is operated; an electrically controllable proportional valve connected to said lines for hydraulic fluid, the proportional valve regulating the flow of hydraulic fluid in said lines for hydraulic fluid; an electric control unit for controlling the proportional valve; and control members for operating each one of the actuating devices. The invention also relates to a method for controlling a boom in a rock drilling equipment, the boom comprising several actuating devices for its different operations; a selector valve for each actuating device; two lines for hydraulic fluid, to which the selector valves are connected in parallel, the selector valve of each actuating device connecting said lines for hydraulic fluid in communication with the respective actuating device when this actuating device is operated; an electrically controllable proportional valve connected to said lines for hydraulic fluid, the proportional valve regulating the flow of hydraulic fluid in said lines for hydraulic fluid; an electric control unit for controlling the proportional valve; and control members for operating each one of the actuating devices. At present, rock drilling equipment typically utilizes in the control of boom actuating cylinders or actuating devices a solution which comprises a single pair of supply and return hoses for hydraulic fluid and in which the different actuating devices are connected by means of their own selector valve in parallel with these hydraulic hoses. Known solutions further comprise a single proportional valve, which regulates the flow of hydraulic fluid in these hydraulic hoses common to the actuating devices. One actuating device at a time is thus used while the others are inoperative, and selector valves are used to select which one of the actuating devices is to be controlled. The proportional valve regulates the amount of hydraulic fluid flowing into and out of the actuating device. A problem with known solutions is that the range of adjustment of the proportional valve always has to be designed according to the actuating device or cylinder having the greatest requirement of volume flow. Accordingly, when small cylinders are con¬ trolled, their speed of movement would be all too high within the entire range of movement of the control member, i.e. a joystick or the like, and they can be adjusted only within very narrow operating ranges of the joystick. This makes the control operation more difficult, as the control easily becomes excessive, which slows down the operation and the use of the device significantly. Similarly, it may damage the device particularly when there is little space and accuracy is required. The object of the present invention is to provide an arrangement and a method, which avoid the drawbacks of known solutions and which allow the entire control range of the control member, such as a joystick, to be utilized. The arrangement according to the invention is characterized in that the arrangement comprises set values preset in the control unit for the different operations, the set values controlling the proportional valve in such a way that when a group consisting of one or more of the actuating devices is operated, the control unit switches the respective selector valves to operating position and starts to control the proportional valve in accordance with operating parameters determined by the set values preset for this particular actuating device group. The method according to the invention is characterized in that set values are preset in the control unit for the different operations, the set values controlling the proportional valve in such a way that when a group consisting of one or more of the actuating devices is operated, the control unit switches the respective selector valves to operating position and starts to control the proportional valve in accordance with operating parameters determined by the set values preset for this particular actuating device group. An essential feature of the invention is that the operating parameters of the proportional valve are preset separately for each actuating device group of one or more actuating devices that the valve regulates so that the parameters vary according to the actuating devices belonging to the actuating device group. The selector valve is thus opened to each actuating device at the same time as the proportional valve starts to use the control parameters or operating parameters corresponding to this particular actuating device or group of simultaneously operated actuating devices. When one actuating device is operated, the operation of the proportional valve can thus be controlled in such a way that it is differently proportional to the adjustment value of the control member when a small hydraulic cylinder is controlled and in the case of a large hydraulic cylinder, for instance. With a small cylinder, the maximum/minimum value of the control member opens the proportional valve only a little, whereas with a large cylinder it opens the propor¬ tional valve wide open. In this way, different adjustment ranges can be provided for each actuating device, if desired. Also, the operation and opening of the proportional valve can be set non-linearly so that they will follow the movement of the control member, whereby operating values appropriate for the operation can be achieved. Correspondingly, when several actuat- ing devices associated with the turning of the boom, for instance, are used simultaneously, the adjustment of the proportional valve can be designed so that when the different actuating devices are operated simul¬ taneously, the movements of the control member are as appropriate as possible for controlling the concerned operation. According to one preferred embodiment of the invention, the control can be realized in such a way that the maximum speed value of a specific actuating device can be arranged to dynamically follow the speeds of movement of the control member so that the greater the speed at which the control member, such as a control lever, is moved, the greater the maximum speed value that can be achieved within predetermined speed limits. Correspondingly, when the control lever is moved slowly, the maximum speed value decreases in a certain proportion to this speed of movement. With large displacements, the speed of movement can thus be increased by moving the control lever rapidly. When precise control is required, the control lever is moved slowly, thus achieving a low maximum speed value and precise positioning. The invention will be described more fully with reference to the attached drawings, in which Figure 1 schematically illustrates a boom with its actuating devices in a rock drilling equipment; and Figure 2 schematically illustrates a hydraulic and electric switching diagram for the arrangement according to the invention. Figure 1 shows a boom 1, which is articulated in a manner known per se to a carrier 2 shown in outline only. A horizontal shaft 3 is shown between the boom 1 and the carrier 2. The boom 1 is able to turn relative to the shaft 3 in the vertical direction. The figure also shows a boom lifting cylinder 4, which is articulated at one end to the carrier 2 and at the other end to the boom 1. As a result, when the cyl¬ inder is extended from the position shown in the figure, the boom 1 will turn upward about the shaft 3. Correspondingly, when the lifting cylinder 4 is shortened, the boom 1 will turn about the shaft 3 downward. The figure further shows partially a feed beam 5, which is connected to the end of the boom 1 turnably about a turning axis 6 shown by a broken line. For this purpose, the equipment comprises a swing cylinder 7, which is so connected that when it is extended, the feed beam will turn in one direction and when it is retracted, the feed beam will turn in the opposite direction. The figure further shows a rotation motor 8, which is connected to rotate the feed beam and components associated with it about an axis of rotation 9 shown in the figure with another broken line. The cylinders 4 and 7 and the rotation motor 8 are typical boom actuating devices of a rock drilling equipment. The hydraulic connections for their operation will be explained more fully with reference to Figure 2. Figure 2 schematically illustrates an arrange- ment according to the invention, where control members 11a to lid are connected to control the proportional valve 13 via a control unit 12. Hoses 16 and 17 for hydraulic fluid pass from a hydraulic pump 14 and a tank 15 to the proportional valve 13. Hydraulic fluid is passed by means of the proportional valve 13 through the hoses 16 and 17 into and away from actuat¬ ing devices 18a to 18d. Each actuating device 18a to 18d has a selector valve 19a to 19d, respectively, the valves being connected to each one of the hoses for hydraulic fluid and to the respective actuating device. The selector valves are used to select the actuating device to be controlled in each particular case. In the control unit 12, control parameters for controlling the proportional valve 13 are preset for each actuating device. When one of the actuating devices, such as 18a, is selected by the control member e.g. by turning it in a certain direction, the control unit 12 switches the selector valve 19a of this actuating device to a desired position either in such a way that the lines for hydraulic fluid will be connected directly to the cylinders of the actuating device or in a crosswise manner with respect to each other so that the actuating device moves in the opposite direction. At the same time, the control unit 12 applies the control parameters to the proportional valve so that the movement of the control lever of the control member in a predetermined direction corre¬ sponds to a predetermined control movement in the actuating device. Correspondingly, the position of the movement of the control member regulates the speed of movement of the actuating device by means of the pro¬ portional valve. For instance, when the control member 11a is turned, it applies a control signal to the control unit 12, which in turn switches the selector valve 19a to a desired position and admits hydraulic fluid into the actuating device 18a. The movement of the proportional valve 13 and the control of the hydraulic fluid have been preset in the control unit 12 as required by the properties of the actuating device 18a and the desired speed. In the same way, specific control parameters have been stored for all the other actuating devices 18b to 18d in the control unit 12. In this way the control can be set so that, for instance, when the control member 11a is used to control the actuating device 18a, the proportional valve 13 allows hydraulic fluid to flow in an amount proportional to the position of the lever of the control member 11a in such a way that the entire range of movement of the lever can be utilized irrespective of the volume of the flow of hydraulic fluid required by the actuating device 18a. For instance, the move¬ ment of cylinders of different diameters can thus be regulated so that the position of the lever of the control member determines the speed, and the control parameters regulate the maximum volume of the flow of hydraulic fluid through the proportional valve 13 in such a way that the largest angle of the lever of the control member corresponds to the maximum flow of hydraulic fluid required by this particular actuating device. When several actuating devices have to be oper¬ ated simultaneously to appropriately effect a certain operation or several simultaneous operations or when the use of several actuating devices effecting move- ment in different directions is natural, such as when turning the boom or feed beam in some direction, it is possible to form different kind of actuating device groups consisting of actuating devices naturally oper¬ ated simultaneously. One such typical actuating device group consists of the cylinders turning the boom in the sideward and vertical direction and the cylinders turning the feed beam in the sideward and vertical direction. There are several other actuating devices naturally forming such an actuating device group. In these cases the set values of the control unit are programmed so that when a single actuating device is used, it has its own set values for regulating the amount of hydraulic fluid flowing through the pro¬ portional valve. When another actuating device is switched on at the same time, the control unit starts to apply the set values corresponding to the actuating device group consisting of these two actuating devices, and so the flow of hydraulic fluid is propor¬ tional to the simultaneous control of the actuating devices. In such a situation it is also possible to define a maximum speed value for a certain actuating device, e.g. the fastest actuating device in the group, the flow of hydraulic fluid being regulated according to this maximum value. In principle, the number of different actuating device groups that can be selected is unlimited, whereby one actuating device group may consist of a single actuating device or all of the actuating devices of the equipment, for instance. In practice, it is simpler to select actuat- ing device groups consisting of actuating devices naturally operated simultaneously, whereby the number of set values to be preset will not be too high. The invention has been described above and shown in the drawings only by way of example, and it is not in any way limited to the examples. The control members can be connected to the control unit and the set values of the operating parameters can be stored in the control unit in different ways by using technical solutions known per se. The operating para¬ meters may also be set to be linear or logarithmic in different ways or in some other way so that a certain flow of hydraulic fluid corresponds to a certain turn¬ ing angle of the lever of the control member.

Claims: Claims : 1. Arrangement for controlling a boom in a rock drilling equipment, the boom (1) comprising several actuating devices (18a to 18d) for its different oper¬ ations; a selector valve (19a to 19d) for each actuat¬ ing device (18a to 18d); two lines (16, 17) for hydraulic fluid, to which the selector valves (19a to 19d) are connected in parallel, the selector valve (19a to 19d) of each actuating device (18a to 18d) connecting said lines (16, 17) for hydraulic fluid in communication with the respective actuating device (18a to 18d) when this actuating device is operated; an electrically controllable proportional valve (13) connected to said lines (16, 17) for hydraulic fluid, the proportional valve regulating the flow of hydraulic fluid in said lines (16, 17) for hydraulic fluid; an electric control unit (12) for controlling the proportional valve (13); and control members (11a to lid) for operating each one of the actuating devices (18a to 18d), c h a r a c t e r i z e d in that the arrangement comprises set values preset in the control unit (12) for the different operations, the set values controlling the proportional valve (13) in such a way that when a group consisting of one or more of the actuating devices (18a to 18d) is oper¬ ated, the control unit (12) switches the respective selector valves (19a to 19d) to operating position and starts to control the proportional valve (13) in accordance with operating parameters determined by the set values preset for this particular actuating device group. 2. Arrangement according to claim 1, c h a r¬ a c t e r i z e d in that the set values preset for the operating parameters of each actuating device group (18a to 18d) are such that the flow of hydraulic fluid through the proportional valve (13) is propor¬ tional to the turning angle of a control lever for the respective control member (11a to lid). 3. Arrangement according to claim 2, c h a r¬ a c t e r i z e d in that at least some of the actuating device groups consist of only one of the actuating devices (18a to 18d), and that the maximum amount of flow of hydraulic fluid through the pro- portional valve (13) , determined by the operating parameters of this kind of actuating device group, has been designed according to the desired maximum operat¬ ing speed of each actuating device (18a to 18d) in such a way that when the control lever of the control member (11a to lid) is in its extreme turning posi¬ tion, said maximum amount of hydraulic fluid flows into the actuating device (18a to 18d). 4. Arrangement according to claim 2, c h a r¬ a c t e r i z e d in that the maximum amount of flow of hydraulic fluid through the proportional valve (13), determined by the operating parameters of each actuating device group, has been designed according to the desired maximum operating speed of the fastest actuating device (18a to 18d) of the concerned actuat- ing device group in such a way that when the control lever of the control member (11a to lid) is in its extreme turning position, said maximum amount of hydraulic fluid flows into said fastest actuating device (18a to 18d). 5. Arrangement according to any of claims 1 to 4, c h a r a c t e r i z e d in that the maximum speed value of each actuating device group (18a to 18d) has been set dynamically so as to correspond to the speed of the control lever of the control member (11a to lid) in such a way that the maximum value will be the higher, the greater the speed at which the control lever moves. 6. Method for controlling a boom in a rock drilling equipment, the boom (1) comprising several actuating devices (18a to 18d) for its different oper¬ ations; a selector valve (19a to 19d) for each actuat¬ ing device (18a to 18d); two lines (16, 17) for hydraulic fluid, to which the selector valves (19a to 19d) are connected in parallel, the selector valve (19a to 19d) of each actuating device (18a to 18d) connecting said lines (16, 17) for hydraulic fluid in communication with the respective actuating device (18a to 18d) when this actuating device is operated; an electrically controllable proportional valve (13) connected to said lines (16, 17) for hydraulic fluid, the proportional valve regulating the flow of hydraulic fluid in said lines (16, 17) for hydraulic fluid; an electric control unit (12) for controlling the proportional valve (13); and control members (11a to lid) for operating each one of the actuating devices (18a to 18d), c h a r a c t e r i z e d in that set values are preset in the control unit (12) for the different operations, the set values con¬ trolling the proportional valve ( 13) in such a way that when a group consisting of one or more of the actuating devices (18a to 18d) is operated, the control unit ( 12) switches the respective selector valves (19a to 19d) to operating position and starts to control the proportional valve ( 13) in accordance with operating parameters determined by the set values preset for this particular actuating device group. 7. Method according to claim 6, c h a r a c¬ t e r i z e d in that set values are preset for the operating parameters of each actuating device group (18a to 18d) in such a way that the flow of hydraulic fluid through the proportional valve (13) is pro¬ portional to the turning angle of a control lever for the respective control member (11a to lid). 8. Method according to claim 7, c h a r a c- t e r i z e d in that at least some of the actuating device groups consist of only one of the actuating devices (18a to 18d), the maximum amount of flow of hydraulic fluid through the proportional valve (13), determined by the operating parameters of this kind of actuating device group, being designed according to the desired maximum operating speed of each actuating device (18a to 18d) in such a way that when the con¬ trol lever of the control member (11a to lid) is in its extreme turning position, said maximum amount of hydraulic fluid flows into the actuating device (18a to 18d). 9. Method according to claim 7, c h a r a c¬ t e r i z e d in that the maximum amount of flow of hydraulic fluid through the proportional valve (13) , determined by the operating parameters of each actuat¬ ing device group, is designed according to the desired maximum operating speed of the fastest actuating device (18a to 18d) of the concerned actuating device group in such a way that when the control lever of the control member (11a to lid) is in its extreme turning position, said maximum amount of hydraulic fluid flows into said fastest actuating device (18a to 18d). 10. Method according to any of claims 6 to 9, c h a r a c t e r i z e d in that the maximum speed value of each actuating device group (18a to 18d) is set dynamically so as to correspond to the speed of the control lever of the control member (11a to lid) in such a way that the maximum value will be the higher, the greater the speed at which the control lever moves.

Inventors: MUONA JOUKO, MUONA, JOUKO
Applicants: MUONA JOUKO, TAMROCK OY, MUONA, JOUKO
Application year: 1995
Main classification: E21C11
IPC codes: E21B7, E21B15, E21B19