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Publication numberUS3456700 A
Publication typeGrant
Publication dateJul 22, 1969
Filing dateJul 10, 1967
Priority dateJul 28, 1964
Publication numberUS 3456700 A, US 3456700A, US-A-3456700, US3456700 A, US3456700A
InventorsAhlstedt Gunnar Lennart
Original AssigneeAhlstedt Gunnar L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of timber sorting
US 3456700 A
Images(5)
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Description  (OCR text may contain errors)

.fiuly 22, 1969 G. L. AHLSTEDT METHOD OF TIMBER SORTING 5 Sheets-Sheet 1 Filed July 10, 1967 Nxxkm wgwifi i y 22,1959 s. L. AHLsTEb-r 3,456,700

METHOD OF TIMBER SOR'IING Filed July 10, 1967 5 Sheets-Sheet 2 llllllllllllllll l' y 1969 5. 1.. AHLSTEDT 3,456,700

METHOD OF TIMBER SORTING I Filed July 10, 1967 s Sheets-Sheet s July 22, 1969 ca. L. AHLSTEDT METHOD OF TIMBER SORTING 5 Sheets-Sheet 4 Filed July 10. 1967 3,456,700 METHOD OF TIMBER SORTING Gunnar Lennart Ahlstedt, Hornett, Alfredshem, Sweden Continuation-impart of application Ser. No. 483,551, Aug. 30, 1965. This application July 10, 1967, Ser. No. 661,487 Claims priority, application Sweden, Aug. 28, 1964, 10,383/ 64 Int. Cl. B27b 1 U.S. Cl. 144312 14 Claims ABSTRACT OF THE DISCLOSURE The invention provides a method and apparatus for the sorting and working of logs, boards and other elongated objects with respect to their end dimension, species, and quality which allows optimum production in a sawmill using the available machines and personnel at a minimum of initial capital expenditure, operation and maintenance costs.

The process sorts logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the available cutting lines, and comprises (1) establishing a range of minimum and maximum end dimensions for cutting in each cutting line, (2) establishing a plurality of different categories of end dimensions within the range of end dimensional limits for each cutting line, said categories being at least equal in number to the number of cutting lines, (3) measuring the end dimensions of the objects to be cut, (4) distributing them to the sorting frames according to their end dimensions, (5) distributing a plurality of the categories within each sorting frame to the respective cutting line for which they are dimensionally suited, and (6) cutting simultaneously the said plurality of categories of each sorting frame, one frame at a time, in the said cutting lines, thus cutting the objects of each sorting frame, in the cutting line.

In this process, the objects preferably are sorted according to their top end dimensions, and the measuring is carried out automatically.

The invention also provides apparatus for sorting logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the avail able cutting lines, which comprises, in combination (1) a plurality of cutting lines, (2) a plurality of sorting frames arranged for reception of a plurality of different categories of end dimensions at least equal in number to the number of cutting lines, (3) means for measuring end dimensions of the objects being sorted, (4) means for conveying the objects from the measuring means to the sorting frames, (5) means for categorizing the end dimensions of the measured objects and automatically selecting and distributing the respective objects to the respective sorting frames for the category to which they belong, and (6) means for distributing a plurality of the respective categories of each sorting frame, one frame at a time, to the respective cutting lines for which they are suitably dimensioned, for cutting simultaneously.

This application is a continuation-in-part of Ser. No. 483,551, filed Aug. 30, 1965, and now abandoned.

This invention relates to a method and apparatus for the sorting of logs, boards, and other elongated objects, which prior to cutting require sorting and storing, according to size and/ or shape, and/ or quality, and/ or material of which they are made, and more particularly to a method and apparatus adapted for use in obtaining maximum utilization of sawmills, pulp mills, and the cutting saw nite States Patent 0 3,456,700 Patented July 22, 1969 frames or lines in other woodworking industries, by a special preliminary sorting of the objects carried out during the transport of the timber to the sorting frames, from which they are conveyed to the cutting frames or lines.

In order to obtain a high utilization of the available equipment for sawing logs to boards and planks, particularly in sawmills, the cutting saws must be supplied continuously with logs, and because of limitations upon the range of top end dimensions a given cutting line can accommodate, the lines are supplied with a plurality of logs of the same top end dimensions at a given time. This means that the logs must be sorted according to their top end dimension, logs having the same top end dimension being stored together in the same bay. To do so, the logs must first be measured, and then sorted accordingly.

Each sorting bay usually holds a quantity of logs, which in the case of a water storage bay corresponds to two to three hours sawing time, or in the case of a land storage bay to from 0.5 to one hour sawing time. Since the logs come in a great variety of top end dimensions, a very large number of sorting bays, and long conveying arrangements from the sorting bays, to the cutting saw line, have to be provided for. A sawmill operating, for example, with four cutting saw lines normally requires from forty to fifty sorting bays, merely for achieving a satisfactory sorting of the logs with respect to the top end dimension. Despite this, during one working day, in the case of water storage, there has to be sawed, in each cutting saw line, logs of at least three different top end dimensions, and this number can be greatly exceeded. This results in a great variety of dimensions and qualities of the lumber, which complicates the subsequent treating and working of the lumber, and particularly its packaging, drying and finishing. The fluctuations in volume, number of pieces, and quality of the finished goods also interferes with a smooth operation.

Moreover, in a given sawmill, different varieties, such as spruce logs and pine logs, have to be sawed at different periods of the year. If, as would be desirable, spruce and pine timber were to be transported together, and sorted at the sawmill at the same time with respect to top end dimension, wood species and quality, about two hundred sorting frames would be required. When it is considered that each sorting bay or frame has a length of twenty feet, it can be appreciated that this not only requires a substantial amount of land space or water space, solely for storage, but also greatly lengthens the conveyors necessary to carry the logs to the frame saw lines. In fact, in such a case the conveyors must be nearly one mile long, which necessitates unrealistically high initial capital expenditure in plants and land, and high repair costs, as well as high cost of operation.

The present invention provides a method and apparatus for the sorting and working of logs, boards and other elongated objects with respect to their top end dimension, species, and quality which allows optimum production in a sawmill using the available machines and personnel at a minimum of initial capital expenditure, operation and maintenance costs.

The process sorts logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the available cutting lines, and comprises (1) establishing a range of minimum and maximum end dimensions for cutting in each cutting line, (2) establishing a plurality of different categories of end dimensions within the range of end dimensional limits for each cutting line, said categories being at least equal in number to the number of cutting lines, (3) measuring the end dimensions of the objects to be cut, (4) distributing them to the sorting frames according to their end dimensions, (5) distributing a plurality of the categories within each sorting frame to the respective cutting line for which they are dimensionally suited, and (6) cutting simultaneously the said plurality of categories of each sorting frame, one frame at a time, in the said cutting lines, thus cutting the objects of each sorting frame in the cutting lines.

In this process, the objects preferably are sorted according to their top end dimensions, and the measuring is carried out automatically.

The invention also provides apparatus for sorting logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the available cutting lines, which comprises, in combination, (1) a plurality of cutting lines, (2) a plurality of sorting frames arranged for reception of a plurality of different categories of end dimensions equal in number to the number of cutting lines, (3) means for measuring end dimensions of the objects being sorted, (4) means for conveying the objects from the measuring means to the sorting frames, (5) means for categorizing the end dimensions of the measured objects and automatically selecting and distributing the respective objects to the respective sorting frames for the category to which they belong, and (6) means for distributing a plurality of the respective categories of each sorting frome, one frame at a time, to the respective cutting lines for which they are suitably dimensioned, for cutting simultaneously.

If the sawmill is provided with two or more cutting saw frames or lines, and each cutting frame or saw line, respectively, is adapted for logs or other objects with top end dimensions varying within a narrow range especially selected for each respective cutting line, if the lines are supplied only with logs of top end dimensions within the range for which they are adapted, and if the sum of the top end dimensions which are simultaneously sawed in all of the lines always is substantially constant (for example, if logs are continuously sawed in three frame saw lines in such a way that the frame saw line I is sawing logs of top end dimension: 2 inches, frame saw line II, a top end dimension of 3 inches, and frame saw line III a top end dimension of 4 inches, the said sum is 9 inches), the consequence is that there is always a substantially constant working load of a constant staff of workmen.

If the sum of the top end dimensions of the logs collected in each respective sorting bay is equal to the abovementioned sum, and if to all of the cutting saw frames or lines are simultaneously fed logs from only one sorting frame, the consequence is that the number of top end dimensions in each respective sorting bay is equal to thenumber of cutting lines, and that the number of sorting bays practically do not have to be greater than the number of the top 'end dimensions fed to the sawmill, divided by the number of cutting lines.

The invention is illustrated in the accompanying drawings, in which:

FIGURE 1 represents a schematic outline of a log sorting and cutting apparatus in accordance with the invention;

FIGURE 2 represents a schematic layout of a typical sawmill in which such apparatus can be utilized;

FIGURE 3 represents a detail view of a cutting saw frame sequence of such apparatus;

FIGURE 4 represents a detail view of a single cutting saw line of such apparatus;

FIGURE 5 represents a log sorting system of such apparatus;

FIGURE 6 represents a detail view of a device for measuring the minimum diameter of a log, to determine top end dimension, in the log sorting system of FIG- URE 5;

FIGURE 7 represents a detail view of a device for measuring the mid-point of a log in the log sorting system of FIGURE 5;

FIGURE 8a is a schematic diagram Showing how four cutting saw lines are utilized in accordance with the invention, in the apparatus of the preceding figures;

FIGURE 8b is a graph of the production of lumber obtainable by use of the four cutting saw lines in this way.

The normal log processing procedure in a sawmill plant is illustrated in FIGURE 2. Logs arriving at the sawmill from the forest normally have to undergo three main operations, debarking, sawing and drying. The initial stages of this sequence are to a considerable extent conditioned by the availability of a large water storage area, since the logs are more easily maneuvered in water. In many sawmills, a large part of the logs to be sawed actually arrive at the mill in enormous floats, which are shown as F in FIGURE 2. The logs arriving by truck T1 are also usually unloaded into the harbor basin. When the logs have been taken from the water, they are put on a conveyor belt carrying them to the debarking machine DB. The logs must enter the debarking machine narrow or top end first, and so if they are fac'mg the wrong way, they must be turned around, (this is detailed in FIGURE 1). Either before or after the de'barking, the logs can be processed in accordance with the invention to determine their important characteristics, according to which they are to be sorted into bays preliminary to cutting.

The sorting is done by way of the conveyor CV which distributes the logs into groups or bays, after which they are stored. After the logs are sorted into bays, they are withdrawn, by groups or bays, for sawing. Prior to the sawing, they are passed across metal detectors M to detect and permit removal of metal objects, stones, and other material that could injure the cutting saws. They are then cut by the saws in the cutting lines, into heart planks h and boards b, and the lumber is sorted at B, placed in stacks St, dried in the drying plant Dr, inspected at I, and then stored at T2.

Ba-rk from the debarker DB is pressed, and can be burned at O for the lumber drying. Sawdust d from the sawmill can be used in the same way. Scrap wood p can be used for pulp.

The determination of the root end dimension, top end dimension, and length, is preferably carried out automatically by automatic measuring equipment. The judgment of the wood species and the quality of the species, together with any projecting portions of the logs, can be carried out advantageously by observation, but although the evaluation is made as an exercise of judgment, it can nonetheless be recorded, and the record then used later in the sorting. To some extent, even this judging can be arranged to be carried out automatically. X-ray analysis of the logs, carried out over a wide range of logs and calibrated, can be used as a measure of quality. A bark testing instrument is capable of detecting differences in the bark on the surface of the logs, and from the numerical measurements obtained, calibrations can be set up distinguishing the various species of timber being processed. Projecting parts on a log can be detected by seeingeye cells or by ultrasonic measurements, and the results of these measurements can be recorded.

The quality determination is primarily carried out for calculating the equivalent to be paid to the deliverer of the raw timber, but it can also be utilized for sorting the logs with respect to quality, and the timber then can be sold according to quality at diiierent prices.

It is particularly advantageous to carry out the determination of root end dimension, top end dimension, and length in a measuring center as shown in FIGURE 5, equipped with electronic measuring instruments, such as a timber measurer, a linear measurer, frame switches, and programming units for the same, as well as with conveyor storage, which latter may also be of the paper type, either magnetic or entirely mechanical. The measuring can also be carried out with mechanical or pneumatic instruments, without the use of electronics. In such a case, the maximum, minimum, and also the mid-dimension of the logs can be determined by photo-electric cells or other suitable measuring devices, for example, of the pneumatic type. The measuring equipment is combined with a counter which at any moment can deliver information on the number of logs contained in every sorting bay, and on the specifications of said logs.

In the measuring center, the logs are passed before a sorting platform, where the logs are measured with the operator placed so that he can observe the logs. The operator is provided with a recording apparatus carrying an indicating system such as, for example, a number of buttons, corresponding to the number of classes or cate gories into which the logs are to be sorted. A tape or strip is used to record the operators observations. The movement of the paper strip is geared directly to that of the conveyor belt running along the platform. The category or class to which the log is assigned by the operator, according to the measurements, is marked on the tape or strip, such as by a punch hole, and as soon as the class has been determined, the log is pushed oft the platform onto the conveyor. A detector such as a photocell is placed at each bay so as to be actuated by the mark on the tape or strip corresponding to each category or class, when the log on the conveyor will have reached the bay corresponding to that category. The detector then energizes a relay, causing a pneumatically or electrically driven lever at the bay to push the log off the conveyor belt into the bay. The strip thus acts as a delay mechanism for bridging the time interval required for the log to be carried from the platform to the right bay. This mechanical delay system is a simple one, and does not involve any real time relationship, but only place relationship. If the conveyor belt is stopped for some reason, so also is the tape stopped, and the logs resting on the conveyor will still be delivered to the right bay when the tape and the conveyor are started up again.

It is apparent that the exact moment when the hole or other mark in the strip corresponding to a given log has to be placed on the strip must be governed not by the operators action in pressing the button, but by the actual arrival of the log at a certain point of the conveyor. Moreover, the length of the log, which may vary from 9 feet to a maximum of 21 feet, must also be taken into account. The levers which push the logs into the bay must not be more than about 9 feet long, as otherwise there would be risk of one lever pushing two logs at the same time. If, on the other hand, a lever of length 9 feet should push a 21 foot log at one end, this log would fall into the bay at an angle, thus seriously hampering further processing. The electronic sorting equipment therefore should contain a device which ensures that the mark for each log is made on the strip at the moment when the mid-point of the log passes over a certain fixed point, so that the selected lever corresponding to the selected sorting bay will be actuated at the moment when the midpoint of the log will pass by it. A system for doing this is shown in FIGURE 7, and will be described later.

It is possible to provide a special button for cancelling the decision of the operator, so that an error can be corrected. Another button can be arranged to take care of the logs in the categories being sawed on that day. This button can actuate a means for throwing the log onto a subsidiary conveyor belt as soon as it comes off the platform. It can then be carried not to the sorting bay but in the opposite direction to the sawing lines.

All the logs sent in either direction are automatically counted. The tape or strip of the delay system can be stored on a large spool, sufficient for three eight hour shifts, for example; a sensing lever pressing against the paper can be arranged to sound an alarm when the paper must be replaced.

The measuring of the diameter of the logs can also be done by means of calipers, or by visual estimation after the operator has gained suflicient experience. All electronic gauge can also be used for this purpose. Such a gauge is shown in FIGURE 6.

The typical log sorting installation as shown in FIG- URE 5 will now be described. OD represents the operators desk, with a panel of punch buttons indicating the categories into which the objects, such as logs, are to be sorted. EC represents the cabinet with the electronic circuit, and the strip or tape of paper on which the category is marked. G represents the gearing by which the movement of the strip is coupled to that of the conveyor belt B1. The various sorting frames or bays R1, R2, R23 are equipped with pneumatically driven levers L1, L2, L23, for ejecting the logs from the conveyor B1 into the respective bays, as actuated by the paper strip. PC represents a lamp and PC a photocell of the midpoint seeking device, shown in detail in FIGURE 7.

The beam of light falling onto the photocell is directed across the path of the logs at point D, situated a distance equal to half the maximum length of a log before C (see FIGURE 7). The beam and hence the photocell current will be interrupted by a passing log, and will reappear when the tail end of the log arrives at D. At this moment, the head of a log of the maximum length would be at E, and its mid-point at C, but the head of a shorter log would only have gotten to E, say, and at mid-point to C. The reappearance of the current cannot thus be used for controlling the actual punching, after the operator has pressed the button. Instead, a switching disk is incorporated in the delay system cabinet, which is started rotating by at angular velocity 00 by the disappearance of the photocell current, i.e., the arrival of the head of the log at D, and which switches on the punch after rotating through a certain angle 0. At the speed to, the rotation through 6 would be completed with a 21 foot log had the correct position D-E, but the shorter log considered above would then have traveled too far, and reached the position D"D. The speed of the disk is, however, doubled by the reappearance of the photocell current (at the tail of the shorter log at D and at E). The remaining part of the rotation through 6 is therefore completed in a shorter time, namely, such that the shorter log would have arrived at the position D"E"', exactly half way between the positions D-E' and DE, and its mid-point will now be at C, where it should be at the moment of punching.

When two relatively short logs are put on the conveyor in quick succession, it may happen that the head of the second log will arrive at D before the switching disk has completed its full rotation for the first log. Another switching disk is therefore provided, the two disks being used alternately by means of an interlocking circuit.

The minimum diameter gauge for the logs is shown in FIGURE 6. This gauge automatically measures the diameter of logs passing through the gauge, and determines for each log the minimum of the number of measurements. The diameters are measured about twenty times per second, and in two perpendicular directions, thus making due allowance for irregularities of the logs. The gauge is provided with twenty-two relays, giving classification signals used for the automatic sorting of the logs, with a resolution of A inch.

The measuring part of the gauge can also be employed for the cumulative determination of the volume of the logs passing on a conveyor into a saw or pulp mill. In that case, certain data processing units used for the determination of the minimum diameter of these logs are replaced by digital units. There are also instances where a combined equipment is preferred, being used for sorting and for volume computing.

The diameter measuring gauge installation as shown in FIGURE 6 comprises a photoelectric measuring device consisting of a V-shaped scanner V, and two separate photo detectors P1 and P2. The scanner has two arms A1 and A2, arranged at angles to each other. Each arm-contains soft lamps S1 arranged in a long row, with a pitch of A inch. The lamps are fed with a reduced voltage permitting a long life. A belt B2 with a slit moves around the rows of lamps on the two arms. The slit allows the light to pass from the lamps, one at a time. The detector P1 receives the pulses thus transmitted from the arm A1, and the detector P2 receives those from A2. Twenty pulse trains are produced per second, and are seen alternately by the two photodetectors, feeding corresponding electrical pulse trains to a primary register in a data processing cabinet. This register counts the pulses received.

The log L passing through the gap between the arms of the scanner, as shown, will screen a number of lamps from the photodetectors, thus reducing the number of pulses transferred from the photodetectors to the primary register. The number of pulses missing is a measure of the thickness of the log.

In addition to the primary register, the cabinet contains another register, used to store the maximum counts for a log being scanned. Two consecutive pulse trains received by the cabinet are compared, and the largest of them is stored in the maximum register. This procedure is repeated for each scan, and when the log is passed, the largest detected pulse frame has thus been selected. This maximum corresponds to the minimum diameter of the log, which is displayed in a binary code in a supplementary register. In addition, two lamp units directed towards a pair of photodetectors are mounted at the opposite sides of the scanner frame. These are used to start and stop the measuring operation for each separate log.

According to sawmill practice, the ends of the logs are usually excluded when the diameters are measured. About 4 inches at both ends must not be scanned. For this purpose, two pairs of lamps of photodetectors are mounted at opposite sides of the scanner frame, and the distance between the units and the travel direction of the logs determines how far from the ends scanning will be started and finished, respectively. By applying this method of measurement, the minimum diameter is correctly determined, whether the top end or the root end of the log is leading, when passing through the scanner.

Logs are classified in accordance with the categories required by the invention. For this purpose, a programming panel is provided, by means of which the classification can be arranged as required. For example, the groups may be chosen in the following way, where sixteen groups are selected. It is possible to distinguish the limits between groups with a resolution of A inch:

Groups: Dimensions (inches) 1 2 Std-5% The gauge of FIGURE 6 thus is provided with twentytwo relays, the output signals corresponding to the classification groups mentioned in the table. These signals are mainly used for the automatic sorting of the logs.

In a log sorting plant, logs are moved by conveyors running along a number of bays for the collection of the different classes of logs, as shown in FIGURE 5. At each bay, the electrically or hydraulically driven levers L1, L2 L23, push the logs off the conveyor belt into the selected bay. These levers are operated by electric signals from the memory device, simulating the logs moving along the bays and remembering their destinations, that is, the categories into which they are being sorted. The signals from the classification relays of the minimum diameter gauge provide information regarding the class destination. When the end of a log is passing the center of the scanner V, that classification relay is energized, which according to the program corresponds to the minimum diameter of the log. This relay is maintained in its operating position until the end of the next log is passing the scanner center, provided the maintaining circuit is not opened earlier.

The data processing cabinet contains the electronic devices needed for counting, comparing and evaluating the pulse trains. The essential electronic devices are de signed in the form of racks, with printed Wiring boards. The basic electronic circuitry is to a large extent made of circuit blocks, small encapsulated standard units painted in a number of color codes corresponding to their functions. All electronic circuits can be transistorized.

The distance between two logs passing the gauge must not fall below 8 inches. As it frequently occurs that logs come closer to each other than that, a device must be installed at the conveyor close to the gauge in order to ensure a correction of the spacing where needed. Such a space-correcting device consists of two pairs of lamps and photodetectors and a relay unit. If two logs are too close, the conveyor is halted for a short time, allowing the necessary gap to be produced, then the delayed log is permitted to continue towards the scanner.

After sorting into bays, the logs are sawed, taking a plurality of the categories from one bay at a time. The usual method for sawing logs in most sawmills is block sawing, shown in FIGURE 3. The cutting saw may, for example, be a circular saw or a bandsaw, but the saw type most widely used is a frame saw, comprising a stand, in which is mounted a displaceable square or rectangular frame equipped with the saw blades. The frame is actuated to carry out vertical movements by a connecting rod mounted between the frame and the rotary fly wheel. In most of the cases, the frame sawing is carried out in such a manner that a first frame sawing machine performs an equal number of cuttings on both sides of the central longitudinal line of the timber, resulting in side boards and a center block. Then the center block is turned to and in a second frame sawing machine, is cut into planks (the central portion) and side boards (the outer portions).

The combination of these frame sawing machines and associated conveying means is called a frame saw line, or cutting line.

A log of length varying between 9 and 21 feet is put on a carriage, and is passed through a reciprocating frame saw (i) containing a number of parallel saw blades SB, which simultaneously cut a number of boards from two opposite sides of the log. These boards, originating from the rounded parts, must be severely cut down in subsequent edging machines, and they usually finish up shorter than the log, because of the taper of the tree. The remaining main part of the log is turned to 90, and passed through another frame saw (ii). Again, only thin and relatively short and narrow boards can be obtained from the rounded sides cut off by the outermost saw blades SE. The spacing of the saw blades in both frame saws should be chosen such that the heavy heart planks, which do not need subsequent edging, and represent the most valuable part of the log, will be as wide and thick as possible, while at the same time the sides of the log should also be used to the greatest advantage, with the least possible amount of scrap wood.

As seen in FIGURE 4, a log is first passed through a frame saw F5 which simultaneously cuts a number of thin boards from both sides; then it is turned to 90 and passed through a second frame saw PS The heart planks H pass out directly, while the thinner boards b must be edged and adjusted in edging saws EG and adjusting saws AD. By-products are scrap wood p for pulp, and sawdust d.

It is evident from the above that the spacing of the saw blades SB, SB in each frame saw must be carefully adjusted in accordance with the thickness of the log. Since the sawmill must deal with logs of widely varying diameter, ranging, for example, from 5 inches to 18 inches, the cutting saw frames must be arranged to deal with logs of a range of diameters, with each cutting saw frame being given a narrow range of diameters, and the total ranges being distributed among the saw frames, so as to accommodate the minimum and maximum diameters to be encountered.

Thus, for example, in accordance with the invention, taking as an illustration a saw mill having four cutting saw lines, arranged to process logs ranging in diameter at the top end dimension from 5 to 12.5 inches, the saw lines can be arranged as follows:

Range of top end Frame saw line: dimensions (inches) Top end dimension (inches) Sorting Sorting Sorting Sorting Frame saw line bay 1 bay 2 bay 3 bay 4 1 And higher.

It will be evident that the total numerical value for each sorting bay is the same, 35.

In accordance with the invention, the contents of each sorting bay is then processed in sequence, the various categories of each bay being cut in the respective frame saw lines noted in the table, or a plurality of categories from a given bay being cut simultaneously, and all of the available saw lines being utilized in this process. In this way, a uniform working load of personnel is obtained, and a maximum utilization of the cutting frame saW lines available.

FIGURE 8a shows how this can be done using the above-described layout of saw lines, sorting bays, and top end dimensions. One bay is sawed at a time, and the dimension categories sent to the saw lines as shown by the arrows.

The production obtainable in this arrangement is graphed in a schematic manner in FIGURE 8b, showing the empirically determined sawing effect, in terms of the number of logs cut per hour, the number of finished products, in pieces per hour, and the volume of finished products from the sawmill, in standard per hour, for the ranges of different top end dimensions of the logs processed in each of the above four cutting saw lines. From information of this type, it will be evident that it can be determined which top end dimensions are best combined to be sawed simultaneously at the available cutting As appears in FIGURE 8b, logs of larger dimensions render a higher total production of finished product volume than raw material of smaller dimensions. For this reason, it is desirable to combine suitable larger and smaller dimensions in every category of dimensions in the sorting frames.

If now it be desired to set up frames for processing both spruce and pine timber, all that is necessary is to double the number of sorting bays fromfour to eight, maintaining the categories of top end dimensions shown in the preceding table. In this way, using only eight sorting bays, the process of the invention makes possible the sorting of two different wood species having sixteen different top end dimensions, i.e., a total of thirty-two different types of material in only eight sorting bays, with only four cutting saw lines.

The number of raw material types can be increased further by introducing into each bay more dimensions than correspond to the number of cutting saw lines. In this case, all of the categories in the bay are not cut simultaneously; the additional categories that are placed in each bay are removed with the others at the time the contents of the bay are being processed, but instead of being distributed to cutting saw lines, these additional categories are distributed into reserve bays, one for each category, for further processing later. This modification is illustrated in FIGURE 1, where it is assumed that the group of sorting bays 22 drawn by full lines is replaced by the second group of bays 22 drawn by dashed lines, to which three further bays are added.

When the number of minimum dimensions introduced into each sorting bay is increased, to exceed the number of cutting sa'w lines by one, each bay will contain five minimum dimensions, i.e., the eight bays 11 will together contain eight additional types of logs, or a total of forty types.

When the four log types normally found in frame 11 are designated by Q, W, X and Y, and the additionally introduced raw material type is designated by Z, and when furthermore each of the log types is to be sorted into three qualities, designated by Q1, Q2, Q3, W1, W2, W3, etc., the sorting and sawing can be performed as follows:

The four conveyors 17 are supplied, for example, with the qualities Q3, W1, X2, and Y3 (corresponding qualities are at this occasion also stored in the reserve storage bay 23). The remaining qualities Q1, Q2, W2, W3, X1, X3, Y1, Y2, are as shown deflected from the conveyors 20, each to its bay 22. The additionally introduced eight raw material types designated by Z are sorted into the qualities Z1, Z2, Z3, and deflected from the conveyor 2*!) to the three additional bays 22, for being stored at a later occasion.

When into each bay 11, two or three additional log types are introduced instead of one, the number of bays 22 must be increased by three and six bays, respectively, for allowing the sorting into three qualities, or, in other words, for a total of fifty-six log types, to be sorted in three qualities, only eight bays 11 and seventeen bays 22 are required.

It is of course also possible to direct logs of different wood species to the same sorting 'bay. In this case, it is to be observed that the top end dimensions of the dif ferent wood species must not be the same in any given bay. So long as the differences in top end dimensions within each category are observed, the contents of the bays can be continued to be maintained separate, according to wood species as well as according to top end dimensions. However, of course, one need not concern oneself with differences in top end dimensions, if the wood species are not to be kept separate in further processing.

FIGURE 1 illustrates an arrangement for carrying out the method according to the invention, and adapted to receive unbarked raw logs, delivered by water as well as overland transport, as shown in FIGURE 2.

The arrangement comprises a sawmill as shown in FIGURES 2 to 4, with four frame saw lines 18, with a receiving station 1 for logs arriving by water transport, and a receiving station 2 for logs transported by land, as in FIGURE 2. The conveyor 3 transports the logs from the receiving stations to the measuring center 9, of the type shown in FIGURES S, where the measurements necessary to sort the logs according to the invention are determined. The conveyor 3 can be a belt, or chain conveyor, or can be composed of transport cars. At the end of the conveyor 3 a combination of metal detectors 4 is mounted, for detecting possible metal objects or stones in the logs. A device 5 mounted at the end of the conveyor 3 moves the log to a conicity sensing member 6, which detects which way the top end and root end of the logs are facing. The conicity sensing member 6 consists of a sloping support, along which the log slips or rolls towards the turning device 7. Above the support, and in sliding contact with the raw material, are arranged two slightly curved arms, at a distance from each other, roughly corresponding to the length of the log, the arms being mounted on a common axis. One of the arms is on a fixed position, whereas the other is pivoted. When the log is transferred from the device 5 to the turning arrangement 7, it passes the conicity sensing member in parallel with the axis of rotation of the pivoted arm, and the arm is lifted to a different height by the log, depending on whether the arm is in contact with the top end or the root end of the log. The relative movement of the arm indicates in which direction the top end is facing on the support, and is used to give an electric impulse, which in turn is passed onto the turning arrangement 7, operating in such a manner that the top end of the log when leaving the turning device always is facing in the same direction.

The turning device may advantageously be constructed in accordance with US. application Ser. No. 435,007, filed Feb. 24, 1965, and consists of a closed track with cars, in which the sensing members give impulses to the platform of returning cars when the raw material points in the wrong direction.

From the turning arrangement, the logs are unloaded onto the conveyor 8, which can be a belt or chain conveyor, or can be comprised of transport cars. The logs are thus transported to the measuring center 9 which is as shown in FIGURES 5 to 7, and as described therein, where the wood species and quality are determined by observation and where the top end, root end and linear dimensions are measured automatically.

The information is reported to the strip 10, which, as described above in connection with FIGURE 5, is kept in synchronization with the conveyor 8, and gives an electric impulse to the deflector means 12, comprising a hydraulically operated deflector arm mounted in front of every sorting bay 11, when a log on a conveyor is to be deflected into a particular sorting bay according to its dimensions. There are in addition, three reserve sorting bays 13, for use when some of the bays 11 are full. There is, accordingly, a total of twenty-three sorting bays in this group.

The logs in the sorting bays 11, which are emptied one at a time for cutting, are transported therefirom to the cutting saw lines 18 by the conveying mechanism 14, which, for example, can be an overhead crane. The conveying mechanism can also be used to transport the contents of each bay to certain storage as described below, and to the dcbarker 15, if debarking of the logs is desired, prior to the cutting.

The debarker 15 is of the conventional type, and comprises a number of knives arranged in a rotor surrounding the log,.and which on rotation of the rotor peel oi? the bark from the leg as it moves through the rotor. The

12 log is introduced into the rotor, small end, i.e. top end, first.

The conveying arrangement 14 transports the logs from each bay, one bay at a time, to the side conveyor 16, where the different top end dimensions of the logs in each bay are sorted visually, and fed onto the conveyors 17, which lead the logs of the predetermined range of top end dimensions appropriate to each of the four cutting saw lines 18. The conveyor 16 has means to separate the different pieces of logs, which often arrive in heaps as they are transported on the conveyor, at an angle to the direction of a conveyor 20 so that they proceed at a velocity low enough to enable visual determination of their top end dimensions. Preferably, the side conveyor 16 is of the conventional chain belt conveyor type with lugs for retaining the logs, operated by a man who directs the raw material to the conveyors 17.

If the raw material is to be debarked, it is transported by the conveying arrangement 14 to the debarker 15, or else directly from the measuring center 9 via the side conveyor 19 (of type similar to conveyor 16) to the conveyor 20, which directs the logs to the debarker 15, where the raw material is sorted visually or automatically with respect to its quality, and debarked. The debarking station is equipped with a storage 21, which is synchronized with the conveyor 20 in like manner to conveyor 8, so that the material after debarking is fed automatically down into eight quality storage bays 22, and four storage bays 23 for a second quality, the third quality continuing directly to the side conveyor 16 to be transported to the cutting saw lines. After the sawing of the third quality, the sawing of the two remaining qualities, first and second, is commenced in the bays 22, or else these qualities are directed to the reserve storage bays 23, for sawing at a later occasion.

The reserve storage 23 can be used for completing the feed, when there is not a suflicient supply of debarked logs in categories for sawing.

24 designates a storage bay for sorted unbarked raw material to be debarked, 25 is a storage bay for logs which include metal objects or stones or show other defects, rendering them unsuitable for direct sawing. 26 is a storage bay for pine timber, and 27 a storage bay for spruce timber, of inferior quality intended to be used as pulp wood, and thus not to be cut in frame saws, but only to be cut in lengths.

Having regard to the foregoing disclosure, the following is claimed as the inventive and patentable embodiments thereof:

1. A process for sorting logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the available cutting lines, which comprises (1) establishing a range of minimum and maximum end dimensions for cutting in each cutting line, (2) establishing a plurality of different categories of end dimensions within the range of end dimensional limits for each cutting line, said categories being at least equal in number to the number of cutting lines, (3) measuring the end dimensions of the objects to be cut, (4) distributing them to the sorting frames according to their end dimensions, (5) distributing a plurality of categories within each sorting frame to the respective cutting line for which they are dimensionally suited, and (6) cutting simultaneously the said plurality of categories of each sorting frame, one frame at a time, in the said cutting lines, thus cutting the objects of each sorting frame in the cutting lines.

2. A process in accordance with claim 1, in which the objects are sorted according to their top end dimensions.

A process in accordance with claim 1 in which the measuring is carried out automatically.

4. A process in accordance with claim 1 in which the objects are logs.

5. A process in accordance with claim 4, which includes debarking the logs prior to the cutting.

6. A process in accordance with claim 1 in which each dimensional category of each sorting frame ditfers from every other by at least one-half inch.

7. A process in accordance with claim 1, in which more categories of end dimensions are established for each cutting line then there are cutting lines, and the additional categories are sorted into reserve sorting frames when the other dimensional categories are distributed to their respective cutting lines for cutting.

8. Apparatus for sorting logs, boards and other elongated objects into a plurality of sorting frames preliminary to cutting in a plurality of cutting lines, in order to obtain optimum utilization of the available cutting lines, which comprises, in combination, 1) a plurality of cutting lines, (2) a plurality of sorting frames arranged for reception of a plurality of different categories of end dimensions, equal in number to the number of cutting lines, (3) means for measuring end dimensions of the objects being sorted, (4) means for conveying the objects from the measuring means to the sorting frames, (5) means for categorizing the end dimensions of the measured objects and automatically selecting and distributing the respective objects to the respective sorting frames for the category to which they belong, and (6) means for distributing a plurality of the respective categories of each sorting frame, one frame at a time, to the respective cutting lines for which they are suitably dimensioned, for cutting simultaneously.

9. Apparatus in accordance with claim 8, in which the measuring means comprises a minimum diameter gauge.

10. Apparatus in accordance with claim 9 in which the gauge comprises a photoelectric measuring device including a V-shaped scanner and two photo detectors disposed across the top of the V.

11. Apparatus according to claim 8 in which the categorizing means includes a tape moving in synchronization with the conveying means, carrying a signal corresponding with the selected category of the object, and actuating distributing means associated with the selected sorting frame for directing the objects from the conveying means into such frame.

12. Apparatus according to claim 11, in which the categorizing means also includes an electronic memory device.

13. Apparatus according to claim 11 in which the categorizing means includes a programming panel for categorizing the objects, and relays giving output signals corresponding to the categories.

'14. Apparatus according to claim 13 including a midpoint determining device to assist in timing the actuation of distributing means for the selected sorting frame.

References Cited UNITED STATES PATENTS GERALD A. DOST, Primary Examiner US. Cl. X.R.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3516539 *May 13, 1968Jun 23, 1970Potlatch Forests IncApparatus for separating and handling a cant and sideboards
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US3554249 *Apr 17, 1968Jan 12, 1971Essem Metotest AbMethod for grading and classifying debranched tree-trunks and similar roundwood according to the usefulness of the wood contained therein, and an apparatus for putting the method into effect
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US7676953 *Dec 29, 2006Mar 16, 2010Signature Control Systems, Inc.Calibration and metering methods for wood kiln moisture measurement
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Classifications
U.S. Classification144/357, 209/518, 144/398, 144/1.1
International ClassificationB07C5/14, B27B1/00, B07C5/04, B65G47/50
Cooperative ClassificationB27B1/007, B07C5/14
European ClassificationB07C5/14, B27B1/00D