Patent Publication Number: US-6991011-B2

Title: Opening rotor type debarking machine

Description:
FIELD OF THE INVENTION 
   The invention relates to a hole-rotor-type barking machine for barking a log to be put axially through the hole-rotor, in which barking machine the barking blades barking the log are so arranged that they can be adjusted during the barking. 
   PRIOR ART 
   The principle of a hole-rotor-type barking machine is to use a rotating rotor which comprises three to six abrasive blades. The log is fed into the rotor by means of a wood-feeding machine attached to the barking machine that has been so arranged as to center the log in the middle of the hole-rotor. While the log approaches the hole-rotor the blades open up. In prior-art barking machines the compression force of the barking blades against the log is achieved by springs and/or hydraulic pressure. 
   The barking happens in the following manner. The log is fed by a log conveying roll to face the rotating blades, in which case the rotating blades open up and start barking the log with a pre-set barking force. At present, the blade force being applied to the barking blades can only be set when the hole-rotor is standing. The blade force can be adjusted by a separate external pneumatic or hydraulic unit. The bigger the pressure applied to the blades by means of the separate unit, the bigger the blade force applied to the log. The adjustment of the blade force considerably influences the capacity of the barking machine because during the adjustment the barking machine is standing. 
   In barking it is important that all the bark is removed from the log, but just the bark and nothing else. Therefore it is important that the log can be centered well, that the shape and condition of the blades are appropriate and that the blade pressure is suitable. In addition, in barking, the butt of the log may be shaped by removing the corresponding butt expansion. Usually, for shaping the butt, a separate hole-rotor-type machine is used. Also here the adjustment of the blade pressure during the machining would considerably improve the capacity and the machining work. 
   With the log properties, such as the thickness of the bark, the moisture, diameter and crooked growth of the log, and the number of the branch stubs, changing it is very important that the blade pressure is adjusted correspondingly. However, at present, the adjustment depends on the activity of the operator of the barking machine and on the other hand on the required capacity of the barking machine. Therefore, the barking machine is usually operated with the wrong blade pressure, in which case the log may get stuck in the barking rotor, or the log may get lathe-turned at the initial step of barking, or there is too little or too much bark removed from the log. 
   OBJECTIVE OF THE INVENTION 
   The objective of the invention is to eliminate the above-mentioned disadvantages connected with the capacity and barking result of prior-art barking machines. 
   One specific objective of the invention is to disclose a new type of barking machine in which the blade pressure can be adjusted during the operation according to the properties of the log being barked, as well as other conditions. 
   One further objective of the invention is to disclose a barking machine which operates with the optimal barking blade pressure of the log, thereby minimizing the bark left in the log being barked without decreasing the capacity of the machine. 
   SUMMARY OF THE INVENTION 
   In the invention there is implemented a barking machine which allows one to bark each log independently based on measurements made of the log by adjusting the blade pressure during the barking. This has been implemented by arranging in the barking rotor a control and adjustment arrangement which allows one to control and adjust the blade pressure of the barking blades while they are rotating and barking the log. The main idea in the invention is to transmit the control and barking force to the rotating barking rotor by adjustment equipment suitable for the purpose. 
   The invention relates to a barking machine which comprises a frame and a barking rotor rotably mounted on the frame. The frame of the barking machine may be a part of bigger log working equipment which in addition to the barking machine may comprise also other log working devices. The barking rotor comprises a rotor frame and barking blades mounted on it. In addition, the barking rotor comprises a first power unit which is attached to the barking blades and the rotor frame for transmitting the barking force to the barking blades. 
   According to the invention, the barking rotor comprises an adjustment device that is so arranged that it is movable with respect to the rotor frame, and a second power unit attached to it that has been mounted on the frame of the barking machine for transmitting the barking force from the adjustment device to the first power unit and further on to the barking blades. Due to this, the rotating rotor need not be stopped when adjusting the blade pressure of the barking blades. The adjustment device is advantageously mounted with bearings on the rotor frame and so arranged that it is movable in the direction of the longitudinal axis of the barking rotor. 
   In one embodiment of the invention, the barking machine comprises a hydraulic system which is connected to the adjustment device, the first power unit and second power unit. The hydraulic system further comprises a hydraulic pump and at least one hydraulic accumulator with a pre-pressure arranged in it. The hydraulic pump is connected to pressure transmission cylinders functioning as the first and second power unit that are used to adjust the blade pressure. In the hydraulic system, pressures are adjusted by means of a pressure regulating valve that has been arranged in the hydraulic system in a manner known in itself. 
   In one embodiment of the invention, the barking machine comprises a measuring device or equipment for measuring the properties of the log to be fed into the barking rotor. The measuring devices may be used to measure the thickness, moisture, temperature, etc. of the log and the bark. In addition, with the measuring devices it is possible to measure the properties of the butt of the log for trimming the butt of the log. In addition, the barking machine comprises a control device for controlling the barking work of the barking machine. Connected to the control device are a measuring device and hydraulic system, in which case the control device can control the operation of the barking machine based on the measuring information received from the measuring device as well as predetermined control parameters and algorithms. 
   Thanks to the present invention, each log being barked can be machined and barked independently based on measurements made of the log just before the barking. The invention brings with it considerable savings, since the barking is done with proper blade pressures on the one hand without leaving bark on the wood due to too delicate a barking and on the other hand without wasting the wood being sawn due to too powerful a barking. Furthermore, thanks to the invention, the real-time blade pressure adjustment of the barking machine becomes robust, and as the costs are concerned, easy and advantageous to implement in the existing barking machines. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following section, the invention will be described with reference to the accompanying drawing, in which 
       FIG. 1  is a schematic diagram illustrating one control and adjustment system of the barking machine in accordance with the invention, 
       FIG. 2  represents one barking rotor in accordance with the invention as seen from the front, 
       FIG. 3  represents a partly sectioned side view illustrating the barking rotor in accordance with the invention, and 
       FIG. 4  represents the hydraulic diagram of one hydraulic system in accordance with the invention 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a diagram illustrating the control and adjustment system of one barking machine in accordance with the invention. This figure shows the part of the barking machine that is used to control and measure the barking process and the properties of the log being barked. A measuring device  12   1  is used to measure, e.g. the diameter of the log, the thickness of the bark, the moisture, freezing degree, and crooked growth of the log. Also other parameters may be measured. The position of the log is measured either by a three-dimensional measuring device or by a separate indicator of log position  12   2 . This information allows one to change the blade pressures so that the log goes into the barking rotor with suitable blade pressures, so that there is no turning occurring. The barking is controlled by means of a controller of barking device  13 , from which there is a connection to the three-dimensional measuring device  12   1 , the measuring of the log position  12   2 , pressure measuring of the hydraulics  14  and pressure regulating valve  10 . Besides, to the controller of the barking device  13  it is possible to connect a PC which enables one to easily change the control parameters. On a PC it is also possible to save the measuring information, for each log independently, the blade pressures used, as well as other possible data originating and used in the barking. 
     FIG. 2  represents one barking machine in accordance with the invention as seen from the front. The barking rotor  2  has been rotably mounted on the frame  1  of the barking machine. The barking rotor comprises a rotor frame  3  and barking blades  4  mounted on it. There are altogether six barking blades in this example. In addition, mounted on the rotor frame is a first power unit  5 , which here consists of six pressure transmission cylinders altogether. The barking rotor comprises also an adjustment device  6  that is so arranged that it is movable with respect to the rotor frame  3 . The adjustment device is a flange-like disc which is pressed by means of a second power unit  7  attached to the barking rotor that here consists of four pressure transmitting cylinders altogether. The flange has been rotably mounted on the barking rotor  2 , and the force of the second power unit  7  is transmitted by means of lever arms  7   a ,  7   b ,  7   c  and  7   d  to the adjustment flange  6 . In addition, the barking rotor comprises a hydraulic accumulator system  11 , in which there is reserved the pre-pressure for the first pressure transmission cylinders  5 . 
     FIG. 3  is a cross-sectional illustration of one barking rotor in accordance with the invention as seen from the side. The barking rotor  2  has been rotably mounted on the frame  1  of the barking machine. In  FIG. 3 , the bearing mounting is illustrated by means of needle bearings N between the frame of the barking machine  1  and the rotor frame  3 . The adjustment of the blade pressure of the barking rotor as described in  FIG. 3  functions as follows. When increasing the pressure of the pressure transmission cylinders  7  the lever  7   a  and  7   c  gets pressed against the adjustment device  6  by means of bearing mounted push-buttons  15 . The adjustment device gets pressed, bearing mounted, further against the hydraulic accumulator system  11  shown in  FIG. 2 , pressing and thereby increasing the hydraulic pressure in the first pressure transmission cylinders  5 . When the pressure of these increases, also the pressure applied to the barking blades increases, and thus the gap between the blades gets smaller, thereby adding to the cutting of the barking blade into the log being barked. When one wishes to decrease the barking force, pressure is released from the pressure transmission cylinders, in which case the adjustment device  6  moves to the left in the direction of the horizontal plane described in  FIG. 3 , thus releasing the pressure of the hydraulic cylinders  5  and thereby the pressure of the pressure transmission cylinders  5 . This adjustment arrangement in accordance with the invention is simple and reliable in operation. It functions reliably also in barking machines in which there are huge twisting and turning forces applied in barking. 
     FIG. 4  further represents the hydraulic arrangement of the adjustment example described in  FIG. 3 , which illustrates the idea of barking of the invention. The figure shows, in diagrammatic representation, the hydraulic system of one barking rotor in accordance with the invention as well as the use of the adjustment device as a part of the hydraulic system in adjusting the blade pressure. The hydraulic system comprises a hydraulic pump  9  which is used to achieve the basic pressure of the hydraulic system. In addition, the system comprises a first set of pressure transmitting cylinders  5 , which are attached to the barking blades  4  for adjusting and maintaining the blade pressure. The second set of pressure transmitting cylinders are practically outside the barking rotor in connection with the adjustment device  6  and via it with the barking rotor  2 . The hydraulic pressure is adjusted by means of a pressure regulating valve  10  and measured by means of a hydraulic pressure meter  14 . The notification informing of the position of the adjustment valve and pressure measurement is transmitted to the control device  13  (not shown in  FIG. 4 ), which further controls the position of the pressure regulating valve based on the data received by it. The adjustment of the pressure regulating valve  10  changes the hydraulic pressure of the second set of pressure transmission cylinders and thus influences the position of the adjustment device  6 , thereby adjusting the pressure of the hydraulic accumulator system  11 . As the pressure of the hydraulic accumulator system  11  changes, also the pressures of the first set of pressure transmission cylinders change, which directly influences the blade pressures of the barking blades  4 . This kind of hydraulic arrangement may, as concerns its mechanical part, be implemented also in some other manner than by using the adjustment device  6  presented in these examples. In the same way, the basic idea of the hydraulic system presented functions also in a pneumatic system, when the pneumatic components have been fitted appropriately. Furthermore, in the adjustment system one has to fit the interoperation of the work cylinders, adjustment device, and other parts appropriately so that the needed hydraulic pressures at the upper and lower limit are achieved. The adjustment is, however, case-specific, depending on the barking rotor being used, number of blades, etc. 
   The invention is not restricted merely to the examples of its embodiments referred to above, instead many variations are possible within the scope of the inventive idea defined by the claims.