Sawmill Method

Abstract

Sawmill methods are provided including automatic log turning methods in combination with improved non-defacing gripping techniques. A pair of gripping arms engage a log on a headblock at oppositely located points adjacent the vertical portion of the headblock so as to be offset with respect to the center of a log. After a first saw cut, the upper gripping arm is removed and the lower gripping arm is raised to rotate the saw log. In a further aspect of the method, a projecting bumper is provided in the vertical portion of the headblock between the log and the upper released gripping arm to assist in turning the log.

Parent Case Text

This application is a division of my copending application, Ser. No. 729,050, filed May 14, 1968, for "Improved Sawmill Apparatus", and now U.S. Pat. No. 3566933.

Description

BACKGROUND OF INVENTION

This invention relates to improved sawmill methods for handling saw logs, and more particularly relates to improved methods for gripping and turning saw logs during the production of lumber.

It is well known that trees are cut down and stripped of their branches to form saw logs, and that the saw logs are thereafter subdivided longitudinally into rectangular portions commonly referred to as boards or planks. In a sawmill the basic equipment includes the saw and the sawmill carriage. The saw may be any suitable cutting mechanism, except that it is usually stationary. However, the sawmill carriage is usually composed of a reciprocally movable device for carrying a log longitudinally to and from the saw, and usually includes a plurality of spaced-apart stops or headblocks each having a pair of pincers for gripping the log.

The saw log is usually rolled down an inclined plane to come to rest on the carriage. The headblocks keep the log from rolling completely over and past the carriage, and also function to grip the log to keep it in a fixed or rigid posture as the carriage is moved toward and past the saw. After the saw has passed longitudinally through the log to cut off an initial slice, the carriage is returned to its original location, the pincers are disengaged, and the log or "cant", as it is then called, is rotated either manually or by separate log-turning devices until it rests on its flat side and against the headblocks. Thereafter, the cant is gripped by the pincers in each headblock assembly, and the carriage is again moved past the saw to cut off another slice. After the carriage is again retracted, the pincers are again disengaged, and the cant is again rotated until it rests on one flat side with the other flat side closely abutting the face of each headblock. Thereafter, the cant is again gripped by the pincers, and the carriage may then be moved repeatedly towards and away from the saw, with the headblocks each being stepped forward in unison a preselected distance after each carriage return, until the cant has been completely sliced into boards.

Although the sawmill carriages and log turners now in use have enjoyed wide acceptance by the industry, it is nevertheless a fact that the equipment now in use incorporates a number of disadvantages. For example, it is usually necessary that the saw logs be delivered in random to the carriage, and thus the logs may vary over a relatively wide range of diameters. Accordingly, many headblocks are provided with a lower or upwardly-engaging pincer and two or more spaced-apart upper or downwardly-engaging pincers, whereby logs of different diameters may be effectively gripped. The upper pincers or teeth are usually spring-loaded to be pushed into the headblock by the abutting surface of the log, but this necessitates that the cant be rotated 270.degree., after each of the two initial cuts, to avoid engaging one of the upper pincers during rotation of the cant.

Another adverse feature of the headblocks of the prior art is that the pincers or teeth are substantially movable only in a vertical direction. Thus, the teeth tend to bite into the "backing board," (the portion of the log or plank remaining in the pincers after the sawing operation has been completed) rather than to grip the board at its edges, and this defaces or damages a board which might otherwise be saleable.

It has long been desired to combine the log turning function with the headblock equipment. Due to the necessity for rotating the cant 270.degree. during each rotation, however, it has been necessary to locate the log turner on the opposite side of the cant from the headblocks. Accordingly, the log turners of the prior art must be separate from the headblocks, and some must be operated separately by different personnel.

Another disadvantage of the headblocks in the prior art is that it is desirable, if not essential, that the square corner of the cant be closely positioned in the corner of the headblock, after the second of the two initial cuts is made. Since the pincers or teeth of these headblocks are selectively movable in generally only a vertical direction, this necessitates that the cant be manually urged into position prior to being sawed into boards. The operator of the conventional log turning equipment is generally assigned to this task, and thus this specific operation does not usually require additional personnel. However, the necessity for manually performing this step has tended to suppress a demand by the industry that the log turning equipment be incorporated into the the headblocks.

These disadvantages of the prior art are overcome by the present invention, and improved sawmill methods are provided for performing both the gripping the log turning operations hereinbefore described.

SUMMARY OF INVENTION

As will hereinafter be explained in detail, a preferred embodiment of the present invention includes an improved sawmill carriage having a conventional carrying frame supporting a plurality of headblocks each having a plurality of arcuately movable dogging pincers or teeth and a bumper arm. More particularly, each of the two teeth is mounted on an arm which is pivotally mounted at a location which is selectively shiftable within limits, whereby the teeth may be selectively extended and retracted as well as urged together and apart.

The pivot points of the tooth arms are preferably spaced apart a preselected distance functionally related to the length of the arms, and are preferably at opposite ends of an equalizer bar or strap which is pivotally connected to a suitable actuator for horizontal movement. Locking means is preferably included for fixing the upper tooth in a raised and retracted position, whereby the lower arm may be raised independently to rotate the cant only 90.degree. to position it on a flat surface. When the upper arm is in this locked position, a bumper arm is preferably extended to aid or facilitate rotation of the log.

Accordingly, it is a feature of the present invention to provide improved saw log gripping and rotating methods.

It is another feature of the present invention to provide improved methods for handling and supporting a saw log during sawing operations.

It is also a feature of the present invention to provide improved log turning methods for rotating a cant through an angle not substantially greater than 90.degree. to rest the cant on its flat side, or 180.degree. to rest cants flat side on front face of knee.

DRAWINGS

These and other features and advantages of the present invention will be apparent from the following detail description, wherein reference is made to the figures in the accompanying drawings.

In the drawings:

FIG. 1 is a pictorial representation, partly in cross section, of an exemplary form of sawmill carriage which can be used in the method of the present invention.

FIG. 2 is a pictorial representation, partly in cross section, of a portion of the apparatus depicted in FIG. 1, and more particularly includes an illustration of suitable vertical guide means for the upper and lower dogging or gripping teeth.

FIG. 3 is a simplified functional representation of the apparatus illustrated in FIG. 1, wherein the teeth are depicted in their expanded and partially retracted position for receiving a saw log.

FIG. 4 is another representation of the apparatus depicted in FIG. 3, wherein a saw log has been deposited on the carriage, and wherein the teeth are spread and extended preparatory to gripping the saw log.

FIG. 5 is a further representation of the apparatus depicted in FIGS. 3--4, wherein the extended teeth have been urged into gripping engagement with the saw log.

FIG. 6 is another representation of the apparatus depicted generally in FIGS. 3-5, wherein one side of the saw log has been cut off to produce a cant, and wherein the upper tooth arm has been raised and locked in a fully retracted and raised position and a bumper arm has been extended.

FIG. 7 is another further representation of the apparatus depicted in FIGS. 3--6, wherein the lower arm has been lifted to raise the engaged side of the cant, and wherein the cant is illustrated as having been pushed upward against the extended bumper arm and thereafter been rotated approximately 90.degree. to rest on its aforementioned flat side.

FIG. 8 is another representation of the apparatus depicted in FIG. 3-7, wherein the cant has been fully sawed into planks or boards, and illustrating the backing board being gripped by the teeth in a non-defacing manner.

FIG. 9 is a pictorial representation, partly in cross section, of the locking mechanism depicted in FIG. 1 during locking engagement with the upper arm.

FIG. 10 is a different pictorial representation, partly in cross section, of the apparatus illustrated in FIG. 9.

FIG. 11 is a schematic representation of a suitable actuating system for operating the apparatus illustrated in FIG. 1.

DETAILED DESCRIPTION

Referring now to FIG. 1, there may be seen an exemplary embodiment of apparatus incorporating various features and concepts for performing the method of the present invention, and being more particularly an improved sawmill carriage assembly 6 including a plurality (usually three knees or headblock assemblies 6A (only one depicted) slidably mounted in spaced-apart relationship on a conventional base to receive and support a saw log as will hereinafter be explained in detail. The base illustrated in FIG. 1, may be composed of a plurality of spaced-apart base members 7 only one being depicted) which, in turn, may be supported on a pair of longitudinal frame members 8 having wheels 9 conventionally adapted to engage and ride on suitable rails (not depicted), whereby the carriage assembly 6 may be reciprocally moved to and from a rotating or moving saw blade (not depicted). As further illustrated in FIG. 1, the headblock assembly 6A may be provided with one or more guides 56 for slidably engaging a skid bar 53 or other suitable means located on the upper side of the base member 7, whereby the headblock assembly 6A may be shifted preselected distances or steps along the skid bar 53 by suitable driving means such as a pinion drive gear 25 rotatably actuated by any suitable source of power and disposed traversely in the base member 7 to engage a suitable rack 26 connected fixedly to the frame of the headblock assembly 6A. In addition, movement of the headblock assembly 6A may be limited in one direction along the skid bar 53 by a suitable stop or bracket 61, as will hereinafter be explained in detail. Alternatively, movement toward the saw blade may be limited by suitable means such as a stop rod 23 located to engage a rattail 22 or other suitable portion of the headblock assembly 6A.

Each headblock assembly 6A may, as illustrated in FIG. 1, be provided with a suitable structural framework composed, for example, of frame braces 48 and 49, a support brace 55, and other suitable members such as the channel member 88 and a pair of vertical channel members (only one depicted) which will hereinafter be referred to as roller guides 12. A suitable dust cover 28 and facing plate 27 may also be included as illustrated in FIG. 1.

As will hereinafter be explained in detail, the illustrated apparatus is preferably arranged to receive a saw log 80 which may be rolled on to and against the skid bar 53 and into abutting relationship with the facing plate 27 as illustrated in FIG. 4. Upper and lower tooth arm assemblies 2 and 4 may then be extended outwardly through a vertical slot in the facing plate 27, and then moved together in the manner of pincers to grip the saw log 80 during reciprocal movement of the carriage assembly 6 to and from the saw blade.

Referring more particularly to FIG. 1, the lower tooth arm assembly 4 may be provided with a suitable lower tooth 5 at one end adjacent a lower roller 11, and may be pivotally connected at the other end to the rattail 22 and one end of an equalizer bar 14 by pivot pin 21. In addition, the lower tooth arm assembly 4 may be supported at a selected point along its length by a dogging actuator 29, which may be composed of a pneumatic cylinder 30 and piston arm 31 pivotally linked to the lower tooth arm assembly 4 by a suitable clevis 32 and clevis pin 33.

The upper tooth arm assembly 2 may be seen to be provided with a suitable upper tooth 3 mounted adjacent an upper roller 10 for downwardly engaging the saw log 80, and pivotally connected at the other end to the other end of the equalizer bar 14 by pivot pin 20. In addition, a connection arm 35 is pivotally attached at one end to the upper tooth arm assembly 2 b pivot pin 36, and at its other end to the upper end of the pneumatic cylinder 30 and one end of a hinge bar 50 by pivot pin 37. The hinge bar 50, in turn, is pivotally secured at its other end to the frame of the headblock assembly 6A, by pivot pin 79 which is fixedly secured to the junction of frame braces 48 and 49, as illustrated in FIG. 1.

The upper and lower tooth arm assemblies 2 and 4 may be moved horizontally to and from the facing plate 27 by a suitable tooth positioning actuator 15 composed of a pneumatic cylinder 17 pivotally secured at one end to a convenient portion of the aforementioned frame by means of a pivot pin 78 mounted in the bracket 77 illustrated. A suitable piston shaft 16 and eye link 54 may be pivotally attached to the middle portion of the equalizer bar 14 by a pivot pin 19. An additional hinge bar 51, which is preferably of substantially the same length as hinge bar 50, may be pivotally interconnected at one end to pivot pin 79 and at the other end to pivot pin 19.

As will be apparent, pivot pins 79 and 78 function as the axes of movement of the upper and lower tooth arm assemblies 2 and 4 by the dogging actuator 29 and the tooth positioning actuator 15. More particularly, the upper and lower tooth arm assemblies 2 and 4 are caused to be moved selectively horizontally, for the purpose of extending and retracting the upper and lower teeth 3 and 5 through a vertical slot in the facing plate 27, by means of air pressure supplied selectively through pneumatic hoses 18 and 52 to the cylinder 17. In other words, when air pressure is received by the pneumatic cylinder 17 through hose 52 (hose 18 then functioning as an exhaust or return line), the upper and lower teeth 3 and 5 may be thrust outwardly through the slot in the facing plate 27 by the driving force supplied by the piston arm 16 through the equalizer bar 14 to the upper and lower tooth arm assemblies 2 and 4. Alternatively, when pneumatic pressure is routed through pneumatic hose 18 to the pneumatic cylinder 17 (hose 52 then providing pneumatic return or exhaust), the piston shaft 16 will retract the upper and lower teeth 3 and 5 by pulling the equalizer bar 14 toward the pneumatic cylinder 17.

On the other hand, it will be seen that when pneumatic pressure is supplied through pneumatic hose 34 to the pneumatic cylinder 30 (the hose 38 functioning as a return or exhaust line, the piston arm 31 and cylinder 30 will be driven together to correspondingly close the upper and lower teeth 3 and 5. Alternatively, when pneumatic pressure is routed to the cylinder 30 through pneumatic hose 38, (hose 34 then acting as the exhaust or return line) the piston arm 31 and cylinder 30 will be driven apart to correspondingly separate the upper and lower teeth 3 and 5.

Although the teeth 3 and 5 are thrust in and out of the slot in the facing plate 27 by the tooth positioning actuator 15, as hereinbefore explained, it should be noted that horizontal movement or travel of the upper and lower tooth arm assemblies 2 and 4 is limited by roller guide 12 located in a vertical position immediately behind the facing plate 27 and adapted to engage the upper and lower rollers 10 and 11. Referring now to FIG. 2, the roller guide 12 may be seen to desirably be composed of a pair of channel members arranged to confront each other for the purpose of enclosing the upper and lower rollers 10 and 11, and preferably spaced apart to provide a gap aligned with the aforementioned vertical slot in the facing plate 27 to permit vertical and horizontal movement of the upper and lower tooth arm assemblies 2 and 4 as hereinbefore explained.

Referring more particularly to FIG. 2, it may be seen that the upper roller 10 may be composed of a pair of coaxially supported roller wheels mounted on each side of the upper tooth arm assembly 2, whereby each of the roller wheels engages the adjacent one of the channels forming the roller guide 12. Similarly, the lower roller 11, which is not visible in FIG. 2, may be also composed of a similar pair of roller wheels also coaxially mounted on the lower tooth arm assembly 4.

As indicated in FIG. 1, the lower tooth arm assembly 4 may be composed of a single strap member. However, it is desirable that the dogging actuator 29 be located directly between the upper and lower tooth arm assemblies 2 and 4. Accordingly, it may be seen in FIG. 2 that it is desirable for the upper tooth arm assembly 2 to be composed of a pair of spaced-apart upper tooth arms 74 and 75 which join together in the manner of a fork adjacent the upper tooth 3 and upper roller 10, and which are fixedly connected at their rearward ends (see FIG. 1) to a spacing bar 104, whereby the pneumatic cylinder 30 may be located between the tooth arms 74 and 75 so as not to interfere with either vertical or horizontal movement of the upper tooth arm assembly 2. A link strap 76, which is preferably pivotally connected at one end to the pivot pin 20, is preferably fixedly secured at its other end to the middle of the aforementioned spacing bar 104 whereby movement of the equalizer bar 14 may be transmitted to the upper tooth arms 74 and 75.

As will hereinafter be apparent, the pivot pin 78 in bracket 77 constitutes one of the main supporting or axis locations in the assembly illustrated in FIG. 1. More particularly, hinge bar 51 may be seen to be pivotally attached at its opposite end to pivot pin 79 which is attached to the ends of conjoining frame braces 48 and 49, and is further pivotally attached by pivot pin 79 to one end of another similar hinge bar 50. The other end of the second hinge bar 50 may be seen to be pivotally connected by pivot pin 37 to the upper end of the dogging actuator 29 (pneumatic cylinder 30) and also to the upper end of a connecting arm 35 which, in turn, is pivotally attached at its lower end to the upper tooth arm assembly 2 by means of pivot pin 36. Accordingly, pivot pin 79 may be seen to provide another supporting axis in the assembly illustrated in FIG. 1.

As hereinbefore stated, the pinion gear drive 25 and rack 26 provides means for shifting the headblock assembly 6A along the skid bar 53 in the direction of the upper and lower teeth 3 and 5 a distance determined or limited by the position of the stop rod 23. It is desirable, however, that means be provided for fairly prompt retraction of the headblock assembly 6A after the log has been completely divided, and thus a suitable retractor 57 may be provided, which may include a pair of pneumatic cylinders 58 (only one being illustrated) each having a single input port connected to a pneumatic hose 59, and each having a suitable piston arm 60 (only one being illustrated) which may be connected to bracket 61 by means of retaining nuts 62 and 63.

As may be seen, pneumatic pressure may be supplied through a pneumatic hose 59 to the pneumatic cylinder 58, and applied to a piston head therein (not depicted) to shift or drive the pneumatic cylinder 58 (and the headblock assembly 6A) towards the bracket 61. Accordingly, as the headblock assembly 6A may be shifted in discrete steps away from bracket 61 by suitable power means (not depicted) connected to the pinion gear drive 25, the headblock assembly 6A will also pull the pneumatic cylinder 58 along the piston arm 60 against the regulated pneumatic pressure trapped between the piston head (not depicted and the end of the pneumatic cylinder 58 to which the pneumatic hose 59 is attached, until the rattail 22 catches the stop rod 23. When it is desired to return the headblock assembly 6A to its original location adjacent the bracket 61, power may be disengaged from the pinion gear drive 25 (and suitable rachet means, not depicted, may be disengaged, whereupon the pneumatic pressure inside the pneumatic cylinder 58 will act as a released spring driving the pneumatic cylinder 58 and headblock assembly 6A rearwardly on the base member 7 to the bracket 61.

Referring again to the structural details of the headblock assembly 6A, there may be seen a suitable bumper arm 13 rotatably mounted on a suitable pin 39, and secured thereto by any convenient means such as a cotter pin 73, whereby one end of the bumper arm 13 may be extended rotatably outward of the headblock assembly 6A when its other end is raised by means of a suitable bumper actuator 42. As illustrated, the bumper actuator 42 may be composed of a suitable pneumatic cylinder 43 having its upper end secured to the frame brace 48 or some other suitable portion of the frame of the headblock assembly 6A, by means of a pivot pin 47, and may further include a suitable piston arm 44 slidably mounted in the cylinder 43 with a clevis 41 attached to the opposite end of the bumper arm 13 by means of clevis pin 40. As depicted, the bumper arm 13 is retracted within the headblock assembly 6A, when pneumatic pressure is applied through pneumatic hose 46 to the pneumatic cylinder 43 to extend the piston arm 44. Alternately, bumper arm 13 is extended when pneumatic pressure is applied to the cylinder 43 through pneumatic hose 45, (pneumatic hose 46 then functioning as the return line) to retract the piston arm 44 within the pneumatic cylinder 43.

As hereinbefore stated, the roller guide 12 may be composed of a pair of confronting but spaced-apart channel members arranged to substantially enclose the upper and lower rollers 10 and 11, as illustrated in FIG. 2, to restrict horizontal movement of the upper and lower tooth arm assemblies 2 and 4. It may be seen in FIG. 1 that flange portions of the channels are convergingly deformed at the upper end of the roller guide 12, and that is upper portion slopes backward away from the facing plate 27, whereby the upper tooth arm assembly 2 is fully retracted when fully elevated for rotation of the saw log 80 or cant 80A, as will hereinafter be explained in detail. In addition, the rearward flange portion of each of the channel members composing the roller guide 12 may, at the lower end of each channel member, be formed in a rearward sloping or step manner. This provides for retardation of upward movement of the lower tooth 5, during downward travel of the upper tooth 3, when the upper and lower tooth arm assemblies 2 and 4 are pulled together to grip the saw log 80.

The purpose of this is to make certain that the saw log 80 is actually seized by the teeth 3 and 5, and is not merely knocked away by the movement of the tooth arm assemblies 2 and 4. If the lower tooth 5 is permitted to engage the saw log 80 prior to engagement by the upper tooth 3, the engaging lower tooth 5 will tend to kick the saw log 80 up and out of range of the downwardly moving upper tooth 3. On the other hand, if the upper tooth 3 drives into the surface of the saw log 80 ahead of the lower tooth 5, the saw log 80 will merely be driven more firmly downward against the skid bar 53 upon which it rests.

In the apparatus illustrated in FIG. 1, the upper tooth arm assembly 2 may be capable of being retained in a retracted and raised configuration within the headblock assembly 6A. Accordingly, a suitable locking means 72 may be provided which is composed of a locking actuator 64 and locking means 72. Referring now to FIG. 9 and 10, there may be seen more detailed illustrations of these components, wherein the locking actuator 64 may include a suitable pneumatic cylinder 65 having pneumatic hoses 67 and 68 for alternately providing pneumatic power and return, and also having a suitable piston arm 69 having a clevis 70 rotatably connected by a clevis pin 71 to the locking means 72. The pneumatic cylinder 65 may be further seen to be attached to a suitable bracket 66 by means of a pivot pin 84 or other convenient connecting means, for the purpose of permitting arcuate movement of the cylinder 65. The locking means 72 may, as illustrated in FIGS. 1, 9 and 10, be composed of a pair of stop arms 83 fixedly attached in a spaced-apart manner to a rocker bar 86. A suitable lever 85, which is pivotally attached at one end to the clevis 70 by the clevis pin 71, may be fixedly secured at its other end to the central portion of the rocker bar 86. The rocker bar 86 may be rotatably supported by a suitable bearing 87 mounted on a convenient portion of the frame work of the headblock assembly 6A, such as on the channel member 88, whereby longitudinal movement of the piston arm 69 may be translated by the lever 85 into arcuate movement of the stop arms 83.

As illustrated in FIGS. 1, 9 and 10, the free traveling ends of the stop arms 83 are preferably inwardly rounded to provide for convenient engagement with the pivot pin 37. Accordingly, when pneumatic power is applied through hose 67 to the cylinder 65 (hose 68 then functioning as a return or exhaust line), the piston arm 69 will be extended to rotate the stop arms 83 arcuately toward and into locking engagement with the surface of the pivot pin 37, when the upper tooth arm assembly 2 is raised to its maximum elevation by the dogging actuator 29. In this configuration, the stop arms 83 prevent the upper tooth arm assembly 2 from being lowered until the piston arm 69 is retracted into the pneumatic cylinder 65, by the application of pneumatic power through the hose 68 (hose 67 then acting as the return or exhaust line).

Referring now to FIG. 11, there may be seen a schematic representation of a suitable pneumatic system for controlling apparatus of the character illustrated in FIG. 1. More particularly, pneumatic pressure may be received form any suitable supply such as a conventional air compressor (not depicted), through line 89 and a conventional lubricator 90, and thence through line 94 to a pressure regulator 91A, whereby pneumatic pressure is continually provided at a suitable pressure such as 45 psig. The dogging actuator 29, which includes a pneumatic cylinder 30 and piston arm 31, as hereinbefore explained, may include a suitable cock or valve 92 electrically actuable by a conventional solenoid 93 for routing pneumatic pressure from the regulator 91A to the cylinder 30 by either hose 34 or 38. The valve 92 may be either normally open or normally closed, for purposes of the apparatus illustrated herein.

It should be noted that the apparatus must be capable of receiving and handling saw logs having a variety of different diameters and weights. It will be apparent that a greater pneumatic pressure will be required to enable the lower tooth arm assembly 4 to kick a large diameter saw log up against the bumper arm 13, than will be required to rotate a smaller diameter saw log. On the other hand, it is desirable to limit the amount of pneumatic pressure being applied to the dogging cylinder 30 when the teeth 3 and 5 are gripping the saw log 80, and especially when the saw log 80 or cant 80A has been cut down to a backing board 82. This is to prevent the teeth 3 and 5 from excessively cutting or gouging the edges of the backing board 82 or the surface of the saw log 80.

Referring now to FIG. 11, it may be seen that provision has been made for the application of limited pneumatic pressure to the dogging cylinder 30 during gripping operations, and for the selective application of high pressure to the dogging cylinder 30 when the log is to be rotated. In particular, high pressure from line 94 may be seen to be applied to the input side of a low pressure regulator 91A, and through line 94A to a supplementary solenoid actuated valve 92A. This supplementary valve 92A is also provided with a separate input port connected to receive this low pressure from the outlet of dogging valve 92 by way of line 34, and to normally conduct this low pneumatic pressure to the dogging cylinder 30 by way of line 34A. Thus, when the dogging valve 92 is open, the piston arm 31 will be retracted into the dogging cylinder 30 to cause the teeth 3 and 5 to grip the log with only moderate or limited force, and cylinder 30 will be exhausted through the dogging valve 92 by way of line 38. Alternately, when the dogging valve 92 is shifted to its alternate condition, low pressure from regulator 91A will be applied to the opposite end of the dogging cylinder 30 by way of line 38 to extend the piston arm 31, and the cylinder 30 will be exhausted through the supplementary valve 92A, and through lines 34 and 34A, to and through the outlet port of the dogging valve 92.

When the log is to be rotated, however, the dogging valve 92 will be shifted to open line 38 to the atmosphere, and the supplementary valve 92A will be simultaneously opened or shifted to close off line 34 from line 34A, and to conduct high pressure from line 94A into the retract side of the dogging cylinder 30 by way of line 34A. This sudden application of high pressure into the dogging cylinder 30 in this manner, will jerk the piston arm 31 into the cylinder 30, thereby jerking the lower tooth arm assembly 4 upward to cause the lower tooth 5 to kick or toss the saw log 80 up against the bumper arm 13 as hereinbefore explained.

As may be seen in FIG. 11 the tooth positioning actuator 15 is operated by high pressure from lines 94, 96 and 97, directly to a suitable valve 105 which may also be actuated by a conventional solenoid actuator 106. More particularly, the high pneumatic pressure from lines 94, 96 and 97, is applied to the pneumatic cylinder 17 by way of either hose 18 or hose 52, and the valve 105 may be either normally open or normally closed for purposes of the present invention. When pressure is received through hose 52, the piston arm 16 will be extended and hose 18 will function as either a return or exhaust line. Alternatively, when pressure is applied to the cylinder 17 by way of hose 18, hose 52 will function as the return or exhaust line, and the piston arm 16 will be returned or retracted into the cylinder 17.

Referring now to the bumper actuator 42 and locking actuator 64, it will be seen that these components do not necessarily carry loads comparable to the loads expected to be borne by the aforementioned dogging actuator 29 and tooth positioning actuator 15. Moreover, the bumper actuator 42 may be expected to be operated only in conjunction with operation of the locking actuator 64. Accordingly, a secondary variable regulator 91 may be interconnected as desired to receive pneumatic pressure from line 96 and to reduce and transmit such pressure through line 98 to a suitable valve 107, which may be either normally open or normally closed for purposes of the present invention, and which may be selectively positioned by a conventional solenoid actuator 108.

As may further be seen in FIG. 11, when the valve 107 is positioned in one of its two alternate conditions, pneumatic pressure from line 98 will be routed to the pneumatic cylinder 65 by way of line 68 (line 67 functioning as a return or exhaust line) to retract piston arm 69. Alternatively, when the valve 107 is shifted to its alternative position or configuration, line 68 will be changed to a return or exhaust line and pneumatic pressure will be routed to the cylinder 65 by way of line 67 to extend the piston arm 69.

It will be seen in FIGS. 6 and 7 that the bumper arm 13 will be extended when the stop arms 72 are rotated for locking engagement with the pivot pin 37. Accordingly, piston arm 44 will be extended when piston arm 69 is retracted, and vice versa, and thus the pneumatic hose 46 is preferably connected between hose 68 and the cylinder 43, and hose 45 is preferably connected between hose 67 and the cylinder 43.

Referring now to the headblock retractor 57, it may be seen in FIG. 11 to preferably include pneumatic cylinders 58 and 100, although only cylinder 58 is depicted in FIG. 1. More particularly, piston arms 60 and 101, which are respectively disposed in cylinders 58 and 100, respectively, may be seen to be fixedly connected to brackets 61 and 102, respectively, to maintain them in stationary relationship to the base member 7, and that the cylinders 58 and 100 are fixedly attached to the headblock assembly 6A and therefore are movably related to the base member 7.

As hereinbefore stated, the headblock assembly 6A including the cylinders 58 and 100 are arranged to be moved in discrete steps away from the brackets 61 and 102, by suitable driving means such as the rack 26 and pinion gears 25 depicted in FIG. 1. As may be seen in FIG. 11, cylinders 58 and 100 are driven toward the saw blade (not depicted) by the rack 26 and pinion 25, and this effectively pulls the rear ends of the cylinders 58 and 100 toward the piston heads contained therein. As suggested in FIG. 11, an appropriate exhaust vent may be provided in each of the cylinders 58 and 100, whereby a corresponding low pressure region is not concurrently created on the opposite side of each piston head. Pressure is maintained on the piston heads, however, from hoses 59 and 59A, and thus when the driving force is removed from the pinion 25, this pressure drives the cylinders 58 and 100 (and thus the headblock assembly 6A) back on the glide bar 53 toward the brackets 61 and 102 respectively. Referring again to FIG. 11, there may be seen a preferred arrangement wherein the regulator 91 also includes pressure relief means for maintaining the pressure in lines 95, 59 and 59A at a constant level notwithstanding travel of the cylinders 58 and 100. In this configuration, the regulator 91 may be adjusted to maintain the pressure in cylinders 58 and 100 at a level adequate to retract the headblock assembly 6A, as hereinbefore described.

Referring now to FIG. 3, there may be seen a representation of the apparatus with the main components arranged in one of several alternate postures. In this posture, the tooth positioning actuator 15 retracts the equalizer bar 14, thereby drawing the upper and lower tooth arm assemblies 2 and 4 into the headblock assembly 6A until the upper and lower rollers 10 and 11 engage or ride against the rear flange of the roller guide 12. In addition, the dogging actuator 29 is raised so as to separate the teeth 3 and 5.

It will be noted in FIG. 3 that, in this position, the upper and lower teeth 3 and 5 are illustrated as extending slightly outwardly through the slot in the facing plate 27. This representation is made only for the purpose of providing a clearer illustration of the configuration of the teeth 3 and 5, however, since the upper tooth 3 is preferably fully retracted behind the facing plate 27, when the upper roller 10 engages the rear flange of the roller guide 12, as will hereinafter be apparent.

Referring now to FIG. 4, it may be seen that a typical saw log 80 has been deposited on the skid bar 53 and adjacent the facing plate 27, by personnel or other means not depicted herein. Accordingly, the tooth positioning actuator 15 may now be operated to extend the separated upper and lower teeth 3 and 5 toward the saw log 80. In this posture, the piston arm 16 is extended outwardly from the cylinder 17 to drive the equalizer bar 14 and the upper and lower tooth arm assemblies 2 and 4 forward until the upper and lower rollers 10 and 11 engage the forward flange of the roller guide 12. Thereafter, the piston arm 31 is drawn into the cylinder 30 to cause the dogging actuator 29 to close the upper and lower tooth arm assemblies 2 and 4 together. Thus, the upper and lower teeth 3 and 5 will grip the surface of the saw log 80 while it is carried toward and past the saw blade (not depicted).

Referring now to FIG. 5, there may be seen a representation of the apparatus wherein the teeth 3 and 5 have engaged the surface of the saw log 80 as hereinbefore described. In addition, a first cut has been made along the outward opposite side of the saw log 80 to provide a first flat surface 81, and the saw log 80 has accordingly been converted or transformed into a cant 80A as hereinbefore explained.

Referring now to FIG. 6, there may be seen a representation of the position of the components of the headblock assembly 6A preparatory to rotation of the cant 80A. In particular, the lower tooth arm assembly 4 remains extended, as hereinbefore described, with the lower tooth 5 engaging the surface of the cant 80A. However, the dogging cylinder 30 may be seen to be raised to its maximum elevation, whereby the upper tooth arm assembly 2 is also raised and urged inwardly by the upper roller 10 riding against the inwardly sloping upper portion of the roller guide 12, and whereby the upper tooth 3 is disengaged from the cant 80A and retracted behind the facing plate 27.

As may be seen in FIGS. 6, 9 and 10, when the dogging cylinder 30 is raised to this position, the locking actuator 64 may not be utilized to lock the dogging cylinder 30 in this raised position during manipulation of the lower tooth arm assembly 4, as will hereinafter be explained. In particular, the locking cylinder 65 is pressured as explained in FIG. 11, and the piston 69 is extended to rotate the lock bars 83 into engagement with the pivot pin 37 from which the dogging cylinder 30 is suspended.

In addition, the bumper actuator 42 (depicted more particularly in FIG. 1) is preferably energized at the same time as the locking actuator 64 as previously explained with respect to FIG. 11. In particular, the piston arm 44 is drawn into the bumper cylinder 43 to rotate the bumper arm 13 outwardly through an appropriate aperture and downward toward the cant 80A, until the piston arm 44 is fully retracted. The dogging actuator 29 is then energized to abruptly raise the lower tooth arm assembly 4 to cause the lower tooth 5 to raise or kick the adjacent lower surface of the cant 80A. The cant 80A is thus raised and thrust against the angularly extending edge of the bumper arm 13, thereby causing it to rotate in a counterclockwise manner and to fall back onto its flat side 81 and to rest on the glide bar 53.

The actuating force applied to the bumper actuator is regulated so that if a log is in contact with the bumper arm 13, the force is insufficient to move the log away from spacing plate 27 before lower tooth 5 has raised the lower surface of cant 80A. Notwithstanding the fact that the cant 80A rotates counterclockwise and away from the facing plate 27, it will usually fall close to the facing plate 27. If necessary, however, the upper and lower tooth arm assemblies 2 and 4 may be seen to be sufficiently maneuverable whereby they may be used to reach out, grip, and pull the cant 80A into abutment with the facing plate 27.

After the cant 80A has been rotated as illustrated in FIG. 7, it is usually preferably to cut another flat surface, as hereinbefore described, before slicing the cant 80A into planks or board. Accordingly, after the second cut has been made, and after a second flat surface has been provided to create a square corner, the cant 80A may then be rotated another 90 degrees to position the original flat surface 81 adjacent to and abutting the facing plate 27. Thereafter, the teeth 3 and 5 may then be engaged, and planks may progressively be cut from the cant 80A until only a single plank or backing board 82 remains gripped between the teeth 3 and 5, as may be seen in FIG. 8. As hereinbefore explained, it is essential that the teeth 3 and 5 be kept out of range of the saw. This is achieved by means of the stop rod 23 which is prepositioned to be caught by the dangling rattail 22, whereby the forward movement of the headblock assembly 6A may be restricted.

Various modifications and alterations may be made in the methods hereinbefore described, and in the structures illustrated in the accompanying drawings. Accordingly, the methods specifically described and depicted herein are intended to be exemplary only, and are not intended as limitations on the essential concept of the present invention.

Claims

What Is Claimed Is:

1. A method of converting a saw log or the like into a four-sided generally rectangular cant, comprising

rolling said saw log onto a horizontal supporting surface and into abutting engagement with a vertically arranged stop,

gripping said saw log at a first pair of upper and lower points on the curved surface of said log adjacent said stop,

slicing a first longitudinal portion from the curved side of said saw log opposite said stop to provide said saw log with a first flat surface parallel with and opposite to said stop,

disengaging said saw log at said first upper point thereon,

applying an upwardly thrusting force to said saw log at said first lower point thereon tending to lift said saw log into sliding engagement at a first diversion point on its upper surface to rotate said saw log approximately 90.degree. in a direction to turn said first flat surface under said saw log and onto said supporting surface, and

regripping said saw log at a second pair of different upper and lower points on the curved surface of said saw log adjacent said stop.

2. The method described in claim 1, including the step of

slicing a second longitudinal portion from the curved side of said saw log opposite said stop to provide said saw log with a second flat surface parallel with and opposite said stop and at substantially a 90.degree. angle relative to said first flat surface,

thereafter disengaging said saw log at said second upper point thereon,

applying an upward thrusting force to said saw log at said second lower point thereon tending to lift said saw log into sliding engagement at a second diversion point on its upper surface to rotate said saw log approximately 90.degree. in a direction to turn said first flat surface into confrontation with said stop and said second flat surface under said saw log and onto said supporting surface, and

regripping said saw log at a third pair of upper and lower points on said saw log adjacent the opposite edges of said first flat surface thereof.

3. The method described in claim 2, including the step of

slicing a third longitudinal portion from the curved side of said saw log opposite said stop to provide said saw log with a third flat surface parallel with and opposite said stop and at substantially a 90.degree. angle relative to said second flat surface,

thereafter disengaging said saw log at said third upper point thereon,

applying an upward thrusting force to said saw log at said third lower point thereon tending to lift said saw log into sliding engagement at a third diversion point on its upper surface to rotate said saw log approximately 90.degree. in a direction to turn said second flat surface into confrontation with said stop and said third flat surface under said saw log and onto said supporting surface, and

regripping said saw log at a fourth pair of upper and lower points on said saw log adjacent the opposite edges of said second flat surface thereof.