CHIP SIZE CONTROL SYSTEM FOR LOG CHIPPING MACHINE

Abstract

A log chipping machine includes a frame having a long axis and a rotating chipping mechanism having an axis of rotation that is oblique to the long axis of the frame of the machine. The machine also includes a log advance system that is adapted to advance a log to the chipping mechanism, in a processing direction that is generally parallel to the long axis of the frame. The log advance system includes an upper feed assembly. A control system includes a lifting assembly and a controller assembly. The lifting assembly is adapted to move the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log. The controller assembly is operatively connected to the lifting assembly and adapted to cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position intermittently in order to orient the log axis in a generally parallel relationship with the long axis of the frame as the log is being reduced.

Claims

1. A log chipping machine for reducing a log having a log axis, said log chipping machine comprising: (a) a frame having a long axis; (b) a rotating chipping mechanism having an axis of rotation that is oblique to the long axis of the frame; (c) a log advance system that is adapted to advance a log to the chipping mechanism, in a processing direction that is generally parallel to the long axis of the frame, said log advance system including an upper feed assembly; (d) a control system comprising: a lifting assembly that is adapted to move the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log; (ii) a controller assembly that is operatively connected to the lifting assembly and adapted to cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position intermittently in order to orient the log axis in a generally parallel relationship with the long axis of the frame as the log is being reduced.

2. The log chipping machine of claim 1 wherein the controller assembly is operatively connected to the log advance system and adapted to cause the log advance system to stop advancing the log to the chipping mechanism while the upper feed assembly is in the raised position.

3. The log chipping machine of claim 1 wherein: (a) the upper feed assembly comprises: (i) an upper feed roller; (ii) a housing that partially encloses the upper feed roller; (iii) a top bar that extends across the top of the housing from one side to the opposite side of the upper feed assembly; (b) the lifting assembly comprises a pair of linear actuators that are located on opposite sides of the upper feed assembly, each of which is attached between the frame of the log chipping machine and the top bar.

4. The log chipping machine of claim 1 wherein the controller assembly is adapted to cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position for a first predetermined time interval and to maintain the upper feed assembly at the raised position for a second predetermined time interval, at the end of which second predetermined time interval the controller will cause the lifting assembly to move the upper feed assembly from the raised position to the engagement position.

5. The log chipping machine of claim 4 wherein after the lifting assembly has moved the upper feed assembly from the raised position to the engagement position and thereafter a predetermined engagement period of time has elapsed, the controller assembly will cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position.

6. The log chipping machine of claim 4 wherein the controller assembly comprises a programmable controller that an operator may use to set a first interval within a first predetermined range of intervals to define the time period between each actuation of the lifting assembly to move the upper feed assembly to the raised position and a second interval within a second predetermined range of intervals to define the time period that the upper feed assembly will be maintained in the raised position, and a timer for measuring the first interval and the second interval.

7. The log chipping machine of claim 6 wherein: (a) the first predetermined range of intervals is 1.0-10.0 seconds, and the first interval may be selected in increments of 0.1 second within this first range; (b) the second predetermined range of intervals is 1.0-3.0 seconds, and the second interval may be selected in increments of 0.1 second within this second range.

8. A log chipping machine for reducing a log having a log axis, said log chipping machine comprising: (a) a frame having a long axis; (b) a rotating chipping mechanism having an axis of rotation that is oblique to the long axis of the frame; (c) a log advance system that is adapted to advance a log to the chipping mechanism, in a processing direction that is generally parallel to the long axis of the frame, said log advance system including an upper feed assembly; (d) a control system comprising: a lifting assembly that is adapted to move the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log; (ii) a controller that is operatively connected to the lifting assembly and to the log advance system, said controller being adapted to cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position intermittently and to hold the upper feed assembly at the raised position for a predetermined period of time while also causing the log advance system to stop advancing the log to the chipping mechanism while the upper feed assembly is in the raised position, after which the controller will move the upper feed assembly from the raised position to the engagement position.

9. The log chipping machine of claim 8 wherein the controller will cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position every 3.0 seconds and will hold the upper feed assembly at the raised position for 1.0 seconds, after which the controller will move the upper feed assembly from the raised position to the engagement position.

10. A method for operating a log chipping machine to reduce a log having a log axis, said log chipping machine comprising: (a) a frame having a long axis; (b) a rotating chipping mechanism having an axis of rotation that is oblique to the long axis of the frame; (c) a log advance system that is adapted to advance a log to the chipping mechanism, in a processing direction that is generally parallel to the long axis of the frame, said log advance system including an upper feed assembly; (d) a lifting assembly that is adapted to move the upper feed assembly with respect to the frame between an engagement position in which the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above and out of contact with the log; wherein the method comprises: (e) operating the rotating chipping mechanism; (f) advancing the log to the chipping mechanism; (g) causing the lifting assembly to move the upper feed assembly from the engagement position to the raised position intermittently.

11. The method of claim 10 which includes causing the log advance system to stop advancing the log to the chipping mechanism while the upper feed assembly is in the raised position.

12. The method of claim 10 which includes moving the upper feed assembly from the engagement position to the raised position every 3.0 seconds and holding the upper feed assembly at the raised position for 1.0 seconds, after which the upper feed assembly is moved from the raised position to the engagement position.

13. The method of claim 10 which includes causing the lifting assembly to move the upper feed assembly from the engagement position to the raised position for a first predetermined time interval and maintaining the upper feed assembly at the raised position for a second predetermined time interval, at the end of which second predetermined time interval the upper feed assembly is moved from the raised position to the engagement position.

14. The method of claim 13 which includes moving the upper feed assembly from the engagement position to the raised position after the upper feed assembly has been moved from the raised position to the engagement position and a predetermined engagement period of time has elapsed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The presently preferred embodiments of the invention are illustrated in the accompanying drawings, in which like reference numerals represent like parts throughout, and wherein:

[0031] FIG. 1 is a side view, partially in section, of a combination debarking and chipping machine that may be equipped with the control system of the invention.

[0032] FIG. 2 is a partial perspective view of an upper feed assembly of a log chipping machine, showing certain portions of the control system of the invention.

[0033] FIG. 3 is a side view of a portion of the upper feed assembly shown in FIG. 2.

[0034] FIG. 4 is a top view of a portion of a log chipping machine showing an upper feed assembly and a chipping mechanism with a log being fed into the chipping mechanism at the desired orientation.

[0035] FIG. 5 is a top view of the portion of the log chipping machine shown in FIG. 4, with the log in a misaligned position.

[0036] FIG. 6 is a top view of the portion of the log chipping machine shown in FIGS. 4 and 5, after the log has been properly aligned according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0037] This description of preferred embodiments of the invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale, and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness.

[0038] As shown in FIG. 1, machine 10 is a combination debarker and log chipping machine that is adapted to process a log such as log 12. Machine 10 includes frame 13 on which the operating components of the machine are mounted. Frame 13 has a long axis F that is shown in FIG. 1. The log is carried through the machine in processing direction D which is generally parallel to frame axis F by a log advance system comprising a plurality of rotating feed rollers. Upper debarker feed assembly 14 is pivotally mounted on the frame 13 of the machine above the log and is adapted to rotate feed roller 15 in a clockwise direction (as shown in FIG. 1). Similarly, upper chipping feed assembly 16 is pivotally mounted on the frame 13 of the machine above the log and is adapted to rotate feed roller 17 in a clockwise direction (as shown in FIG. 1). Lower feed assemblies are mounted below the log and includes rollers 18 and 20 that are adapted to rotate in a counterclockwise direction (as shown in FIG. 1). Upper feed roller 15 and lower feed roller 18 cooperate to move log 12 into contact with debarking assemblies 21, 22 and 23. Each of the debarking assemblies includes a rotating shaft 24 to which are attached a plurality of flail chains 25. Each rotating shaft 24 rotates about an axis of rotation that is perpendicular to the plane of the page of FIG. 1. Each flail chain has a fixed end 26 that is attached to a shaft and a free end 27. Each flail chain is of a length that defines an arc of rotation A.sub.R of the free end 27 of the flail chain 25. Rotation of the shafts causes the chains to flail the bark from the log. As shown in FIG. 1, the shaft of first upper debarking assembly 21 rotates in a clockwise direction, while the shafts of lower debarking assembly 22 and second upper debarking assembly 23 rotate in a counterclockwise direction. Upper debarking assemblies 21 and 23 include housings 28 and 29 respectively that are pivotally mounted to the frame of machine 10. Much of the bark that is removed by the flail assembly falls into bark removal conveyor 30 for removal from the machine. A flailed log advance system comprising upper feed roller 17 and lower feed rollers 20 cooperate to advance the flailed log into a chipping mechanism comprising chipper disc 32, which rotates in a clockwise direction (as shown in FIG. 1) to reduce the log to chips that pass out of the machine through chute 34.

[0039] FIGS. 2 and 3 illustrate a portion of an upper feed assembly 36 which is similar to upper chipping feed assembly 16 of machine 10, as well as certain portions of the control system of the invention. These drawings show upper feed assembly 36 in some detail, including housing 38 that partially encloses an upper feed roller (not shown, but substantially similar to upper feed roller 17 of machine 10). Housing 38 includes top portion 40 and a pair of sidewalls, only one of which, sidewall 42, is shown in the drawings. Top bar 44 extends across the top of the housing from one side to the opposite side of the upper feed assembly, as best shown in FIG. 2.

[0040] The lifting assembly comprises a pair of linear actuators, only one of which, linear actuator 46, is shown in the drawings. These linear actuators are attached between frame components of the log chipping machine, only one of which, frame component 48, is shown in the drawings, and top bar 44 of upper feed assembly 36 on opposite sides of assembly 36. The second actuator is located on the opposite side of upper feed assembly 36 from actuator 46 and is also disposed between a frame component of the log chipping machine and top bar 48 in the same angular configuration as that of actuator 46.

[0041] A controller assembly, such as controller assembly 50 shown in FIG. 1, which is located in operator's station 52, is operatively connected to the lifting assembly and adapted to cause the lifting assembly to move the upper feed assembly from an engagement position in which the upper feed roller of the upper feed assembly contacts the log to advance it towards the chipping mechanism and a raised position in which the upper feed assembly is above the log and the upper feed roller is out of contact with the log. Preferably, control assembly 50 includes a programmable controller and a timer. The inventors have found that moving the upper feed assembly from the engagement position to the raised position intermittently will orient the log axis in a generally parallel relationship with the long axis of the frame of the log chipping machine as the log is being reduced into chips. Preferably, the controller assembly is also operatively connected to the log advance system and is adapted to cause the log advance system to stop advancing the log to the chipping mechanism while the upper feed assembly is in the raised position.

[0042] Preferably, the controller assembly is adapted to cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position for a first predetermined time interval and to maintain the upper feed assembly at the raised position for a second predetermined time interval, at the end of which second predetermined time interval the controller will cause the lifting assembly to move the upper feed assembly from the raised position to the engagement position. After the lifting assembly has moved the upper feed assembly from the raised position to the engagement position and thereafter a predetermined engagement period of time has elapsed, the controller assembly will preferably cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position.

[0043] It is also preferred that the controller assembly comprise a programmable controller which is operatively connected to a controller interface that an operator may use to set a first interval within a first predetermined range of intervals to define the time period between each actuation of the lifting assembly to move the upper feed assembly to the raised position and a second interval within a second predetermined range of intervals to define the time period that the upper feed assembly will be maintained in the raised position, and a timer for measuring the first interval and the second interval. Furthermore, it is preferred that the first predetermined range of intervals is 1.0-10.0 seconds, and that the first interval may be selected in increments of 0.1 second within this first range. It is also preferred that the second predetermined range of intervals is 1.0-3.0 seconds, and that the second interval may be selected in increments of 0.1 second within this second range. The inventors have found that very good results can be obtained when the controller will cause the lifting assembly to move the upper feed assembly from the engagement position to the raised position every 3.0 seconds and will hold the upper feed assembly at the raised position for 1.0 seconds, after which the controller will move the upper feed assembly from the raised position to the engagement position.

[0044] FIGS. 4-6 illustrate a portion of a log chipping machine showing upper feed assembly 54 and chipping mechanism 56 with a log being fed into the chipping mechanism. As shown therein, chipping mechanism 56 has an axis of rotation A that is oblique to the long axis F of the frame. In other words, chipping mechanism 56 is oriented with respect to the frame of the log chipping machine so that its axis of rotation A forms an angle with respect to long axis F of the machine frame. As shown in FIG. 4, log 58 having log axis L is being fed into the chipping mechanism at the desired orientation. In the orientation shown in FIG. 4, log axis L is generally parallel to the long axis F of the frame. Frequently when the log is shortened, it will misalign, as shown in FIG. 5, so that long axis L is not parallel to frame axis F. However, the inventors have found that moving the upper feed assembly from the engagement position to the raised position intermittently will orient the log axis L in a generally parallel relationship with the long axis of the frame F of the log chipping machine as the log is being reduced into chips, as shown in FIG. 6.

[0045] The invention also includes a method for operating a log chipping machine having a lifting assembly and a rotating chipping mechanism as described herein, to reduce a log having a log axis. The method comprises operating the rotating chipping mechanism, advancing the log to the chipping mechanism and causing the lifting assembly to move the upper feed assembly from the engagement position to the raised position intermittently. Preferably, the method includes causing the log advance system to stop advancing the log to the chipping mechanism while the upper feed assembly is in the raised position. It is also preferred that the upper feed assembly be moved from the engagement position to the raised position every 3.0 seconds and that the upper feed assembly be held at the raised position for 1.0 seconds, after which time, the upper feed assembly is moved from the raised position to the engagement position.

[0046] The inventors have found that lifting the upper feed assembly at an appropriate time and for an appropriate period of time will permit the restrained end of a pivoted shortened log to realign to the desired spout angle and will not adversely affect the chipping operation when the log is properly aligned. The automatic control system of a preferred embodiment of the invention will lift the upper feed assembly periodically to allow for re-alignment of a misaligned log, and will hold the upper feed assembly in a raised position for a short period of time. Then, the system will automatically lower the upper feed assembly so that its feed roller will engage the log, thus allowing a shortened log to shift over to the correct alignment. It has been found that this brief period during which the upper feed assembly is lifted out of engagement with the log does not significantly reduce the log feed speed toward the chipping mechanism.

[0047] Although this description contains many specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of the presently preferred embodiments thereof, as well as the best mode contemplated by the inventors of carrying out the invention. The invention, as described and claimed herein, is susceptible to various modifications and adaptations, as would be understood by those having ordinary skill in the art to which the invention relates.