MULTIPLE SHAKE BOARD SPLITTER
United States Patent 3802473
A plurality of parallel froes form the bottom of a chamber in a frame for receiving a block to be split into shake boards. The frame guides a head reciprocable by a hydraulic ram downward against the upper end of the block to force its lower end against the froes for splitting. The froes supported on the upper ends of swingable legs can spread as the froes penetrate the block to compensate for the kerfs formed by the froes between the shake boards into which the block is split.
US Patent References:
Apparatus for splitting logs and the like
Gorrie - February 1922 - 1406552
Splitting machine
Hilke - July 1937 - 2087321
Apparatus for splitting wood blocks
Von Der Werth - July 1950 - 2514915
Apparatus for splitting logs and the like
Gorrie - February 1922 - 1406552
Splitting machine
Hilke - July 1937 - 2087321
Apparatus for splitting wood blocks
Von Der Werth - July 1950 - 2514915
Application Number:
05/248235
Publication Date:
04/09/1974
Filing Date:
04/27/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
144/13
International Classes:
B27L7/00; B27M3/02; B27M3/02; B27L7/00
Field of Search:
144/192,193,194,13
Primary Examiner:
Schran, Donald R.
Attorney, Agent or Firm:
Beach, Robert W.
Claims:
I claim
1. A multiple shake board splitter comprising a frame having a block-receiving chamber, a group of substantially parallel elevationally stationary froes beneath and forming the bottom of said chamber, having upper splitting edges engageable by the lower end of an upright block to be split, and means for moving such block downward against said froes, for splitting the block into shake boards and for moving such shake boards downward completely past the splitting edges of said froes.
2. The splitter defined in claim 1, the means for moving the block against the froes including a presser head engageable with the upper end of the block and movable downward a distance greater than half the length of said block to insure splitting of the block throughout its length by the froes.
3. The splitter defined in claim 1, and means supporting the froes to leave a board-receiving space below the central portions of the froes unobstructed for a distance at least equal to the length of the block being split for passage of split shake boards into such space.
4. The splitter defined in claim 3, the means supporting the froes being movable for spreading transversely of their lengths as the block is moved lengthwise into splitting relationship with the froes.
5. The splitter defined in claim 4, the means supporting the froes including legs supporting the respective froes on their upper portions for swinging of said legs outward from an upwardly convergent relationship to spread the froes.
6. The splitter defined in claim 4, resilient means urging adjacent froes away from each other, and confining means pressing the froes toward each other in opposition to said resilient means and releasable to enable said resilient means to move the froes apart so that split shake boards can fall freely between the froes into the board-receiving space.
7. The splitter defined in claim 4, and stop means for limiting approach movement of the froes in any of various selected positions.
8. The splitter defined in claim 7, and gauge means for altering the limit of the spacing to which the froes can contract.
9. The splitter defined in claim 8, in which the gauge means includes a block engageable by the stop means.
10. The splitter defined in claim 9, in which the gauge means includes a double-stepped block carrying means engageable by the stop means.
11. The splitter defined in claim 1, leg means supporting a froe for movement transversely of its length, pivot means mounting said leg means for swinging between inclined positions at opposite sides of a vertical plane, and means initially positioning adjacent leg means in upwardly convergent relationship.
12. The splitter defined in claim 1, a pair of parallel upright legs supporting each froe at their upper ends, pivot means supporting said pairs of legs for swinging of adjacent leg pairs from an upwardly convergent relationship to an upwardly divergent relationship, and means initially positioning adjacent leg means in upwardly convergent relationship.
13. The splitter defined in claim 3, in which the means supporting the froes includes two legs supporting each froe which legs are spaced apart lengthwise of the froe for supporting opposite end portions of such froe on the upper end portions of said legs, respectively, while leaving the space between said legs unobstructed for reception of pieces split by the froe and moving past and beyond the froe.
14. The splitter defined in claim 13, in which the upper ends of the legs are slotted for reception of the opposite end portions, respectively, of the froe.
15. The splitter defined in claim 3, and discharge conveyor means extending through the board-receiving space for receiving and removing shake boards split from a block and falling between froes above said conveyor means.
1. A multiple shake board splitter comprising a frame having a block-receiving chamber, a group of substantially parallel elevationally stationary froes beneath and forming the bottom of said chamber, having upper splitting edges engageable by the lower end of an upright block to be split, and means for moving such block downward against said froes, for splitting the block into shake boards and for moving such shake boards downward completely past the splitting edges of said froes.
2. The splitter defined in claim 1, the means for moving the block against the froes including a presser head engageable with the upper end of the block and movable downward a distance greater than half the length of said block to insure splitting of the block throughout its length by the froes.
3. The splitter defined in claim 1, and means supporting the froes to leave a board-receiving space below the central portions of the froes unobstructed for a distance at least equal to the length of the block being split for passage of split shake boards into such space.
4. The splitter defined in claim 3, the means supporting the froes being movable for spreading transversely of their lengths as the block is moved lengthwise into splitting relationship with the froes.
5. The splitter defined in claim 4, the means supporting the froes including legs supporting the respective froes on their upper portions for swinging of said legs outward from an upwardly convergent relationship to spread the froes.
6. The splitter defined in claim 4, resilient means urging adjacent froes away from each other, and confining means pressing the froes toward each other in opposition to said resilient means and releasable to enable said resilient means to move the froes apart so that split shake boards can fall freely between the froes into the board-receiving space.
7. The splitter defined in claim 4, and stop means for limiting approach movement of the froes in any of various selected positions.
8. The splitter defined in claim 7, and gauge means for altering the limit of the spacing to which the froes can contract.
9. The splitter defined in claim 8, in which the gauge means includes a block engageable by the stop means.
10. The splitter defined in claim 9, in which the gauge means includes a double-stepped block carrying means engageable by the stop means.
11. The splitter defined in claim 1, leg means supporting a froe for movement transversely of its length, pivot means mounting said leg means for swinging between inclined positions at opposite sides of a vertical plane, and means initially positioning adjacent leg means in upwardly convergent relationship.
12. The splitter defined in claim 1, a pair of parallel upright legs supporting each froe at their upper ends, pivot means supporting said pairs of legs for swinging of adjacent leg pairs from an upwardly convergent relationship to an upwardly divergent relationship, and means initially positioning adjacent leg means in upwardly convergent relationship.
13. The splitter defined in claim 3, in which the means supporting the froes includes two legs supporting each froe which legs are spaced apart lengthwise of the froe for supporting opposite end portions of such froe on the upper end portions of said legs, respectively, while leaving the space between said legs unobstructed for reception of pieces split by the froe and moving past and beyond the froe.
14. The splitter defined in claim 13, in which the upper ends of the legs are slotted for reception of the opposite end portions, respectively, of the froe.
15. The splitter defined in claim 3, and discharge conveyor means extending through the board-receiving space for receiving and removing shake boards split from a block and falling between froes above said conveyor means.
Description:
The machine of the present invention facilitates the splitting of a block into shake boards which can be resawn to form resawn shakes or resplit to form split shakes.
For many years shakes for roofing and siding have been split one at a time by hand. More recently shake-splitting machines have been used by which shake boards for resawing or finished shakes have been split one at a time. Sawn shingles are sawn one at a time from a shingle block.
The principal object of the present invention is to split a block into a plurality of shake boards in a single pass of the block and splitting froes and to accomplish such operation mechanically.
A further object is to provide such a shake-splitting machine in which a block can be set easily in relationship to splitting froes to produce the best shake boards.
Another object is to provide for automatic removal of split shake boards from the splitting machine.
By provision of a one-pass mechanical shake-splitting machine it is an object to expedite the splitting of shake boards from a block to reduce the labor required to effect such splitting and to produce shake boards which are more uniform and of better quality.
It is also an object to provide a one-pass shake-splitting machine which is of rugged construction yet which is compact and the parts of which are readily accessible for repair or replacement.
FIG. 1 is a plan of a representative arrangement of two single-pass shake-splitting machines according to the present invention which can be operated by a single splitterman.
FIG. 2 is an end elevation of the shake-splitting machine, parts being broken away, and FIG. 3 is a side elevation of such machine.
FIG. 4 is a vertical section through the machine taken on line 4--4 of FIG. 3.
FIG. 5 is a detail top perspective of a portion of a froe and its support showing the parts in exploded relationship.
FIGS. 6, 7, 8 and 9 are enlarged side elevations of the lower portion of the shake-splitting machine showing parts in different positional relationships and having parts broken away.
Two shake-splitting machines of the present invention can, for example, be arranged at opposite sides of a feed table 2 in front of which a splitterman S stands, as shown in FIG. 1. Blocks B to be split into shake boards are supplied to the feed table 2 by a conveyor 3. The splitterman will grasp each block, examine it to determine the position in which it should be placed to be split into the best shake boards SB and slide it into one or the other of the shake board splitting machines 1 in such position. Shake boards SB split from such blocks will fall onto a discharge conveyor belt 4 which will carry the shake boards away from the machine automatically to be stored or to be resawn into shakes.
As shown best in FIG. 4, a block B is slid by the splitterman from the feed table 2 across an apron 5 into the block-receiving chamber of the frame 6. In that position the lower end of the block B is resting on the splitting edges of a plurality of froes 7. The presser head 8 is located above the block in the upper end of the block-receiving cavity. Such presser head is mounted on the lower end of piston rod 9 of a hydraulic ram 10. Such ram is mounted on the upper portion 11 of the machine frame.
Vertical reciprocation of the presser head 8 by the hydraulic ram 10 is effected by controlling the supply of hydraulic liquid to the ram by the valve 12 shown in FIG. 2. Such valve is operated to reciprocate the valve stem 13. The bell crank 14 has an upright arm connected by a link to the valve stem 13. The generally horizontal arm of such bell crank is connected to the actuating rod 15 guided for vertical reciprocation relative to the frame 6. Such rod is reciprocated by a projection 16 carried by the presser head 8 for engagement with upper and lower nuts or set collars 17 and 18 adjustable along the rod 15.
The upper end of the reciprocating rod 15 is received in a friction or holding device 19 which will normally hold the actuating rod 15 in the position to which it has been adjusted. To split the block in the actuating rod is voluntarily reciprocated by swinging lever 20 connected by pivot 21 to the lower end of the rod. Such lever is swung by the splitterman stepping on the end 22 of the lever.
When a block B has been placed in the splitter by the splitterman in the position shown in FIG. 4, the splitterman will step on the end 22 of lever 20 to reciprocate actuating rod 15 upward from the position shown in FIG. 2. Such upward movement of the actuating rod will swing bell crank 14 to reciprocate the stem 13 of valve 12 to the right. Such movement of the valve stem will effect a supply of liquid under pressure to the upper end of ram 10 so that the presser head 8 will be forced downward, first into engagement with the upper end of the block B and then for driving the block through the group of froes 7 until it has reached the broken-line position of FIG. 2.
As the presser head 8 approaches the broken-line position of FIG. 2 or the solid line position of FIG. 7, arm 16 projecting from it will engage the nut or collar 18 on the actuating rod 15 and shift this actuating rod downward for swinging bell crank 14 to move the valve stem 13 to the left. Movement in this direction will be sufficient, not only to cut off the supply of liquid under pressure to the upper end of the ram 10, but also to connect the supply of liquid under pressure to the lower end of the ram and provide for discharge of liquid from the upper end of the ram. The ram will then raise the presser head back to the solid-line position of FIG. 2, at which time the arm 16 carried by it will engage the nut or collar 17 to raise the actuating rod 15 sufficiently to swing bell crank 14 for shifting the valve stem 13 to the right a sufficient distance to center such stem and thereby to cut off the supply of liquid under pressure, both to the lower end and to the upper end of ram 10 for bringing the presser head to a stop in preparation for commencement of the next splitting operation initiated by depressing the end 22 of lever 20 as described above.
As shown best in FIG. 5, each end of each of the froes 7 has an end projection 24 of a size to slide edgewise into an upwardly opening slot 25 in the upper end of a swinging leg 26. The lower end of each such leg is mounted by a pivot pin 27, shown in FIG. 3, extending through a bore 28 in the lower end of the leg. The legs supporting opposite ends of each froe are spaced apart sufficiently to accommodate between them the conveyor belt 4 for removing the shake boards.
As shown in FIG. 6 the splitting edges of the froes 7 engage the end of block B along parallel lines. As the block is pushed endwise against the froes, the tapered cutting edges penetrate the block. Since such cutting edges effect a splitting action on the block rather than a sawing action, no wood is removed from the block. Consequently it is necessary for the split surfaces of the block on each side of a froe to separate a thickness equal to the distance of the froe in order for the froe to continue to enter the block.
Because such spreading action is cumulative across the width of the block, the outer elements of the block transversely of the froes must separate a distance equal to the combined thickness of all the froes. In order for each froe at opposite sides of the center froe or froes to remain in registration with their respective locations of split, therefore, the froes must be spread from the relationship shown in FIG. 6 to that shown in FIG. 7 between the time of initial penetration of the splitting edges of the froes into the block end and penetration of the froes into the block to their locations of maximum thickness. Mounting of the froes on the swinging upper ends of the legs 26, as mentioned previously, enables such spreading action of the froes to occur.
In order to position the froes 7 in the proper contracted relationship for initial engagement by the end of a block B to split it into shake boards of the desired thickness, mechanism is provided to locate the froes in such contracted relationship. Such mechanism includes gauging stop blocks 29 mounted on the several legs in staggered relationship as shown in FIG. 6. In order to enable the position of each froe to be adjusted individually relative to the adjacent froes, a spacer screw 30 is threaded in each gauge stop block and projects from its stop block transversely of the lengths of the legs 26 for abutment with an adjacent stop block. Each spacer screw has a lock nut that can be tightened against the stop block in which the spacer screw is threaded to hold such screw in any desired adjusted relationship.
As is evident from FIG. 6 the spacer screws 30 will only limit approach movement of the froes 7. In order to assure that the froes are held in their contracted relationship when a block B is placed on them, therefore, resilient contracting means are provided to press the froe-supporting legs 26 together. Such contracting means includes presser rods 31 connected by pivots 32 to brackets carried by the outer legs 26 at opposite sides of the froe assembly. These rods are urged yieldingly toward each other by penumatic jacks 33.
In order to be able to effect spreading of the froes 7 without pressing a block B against their splitting edges, mechanical spreading means for the legs 26 are provided. Such spreading means include blocks 34 mounted in staggered relationship on the legs in addition to blocks 29. Each of such blocks is apertured to receive slidably through it a bolt 35 having its length extending transversely of the length of the legs 26. The threaded end of such bolt is anchored by being screwed into a block adjacent to the block through which it extends slidably, and such threaded end is secured in place by a lock nut. A compression spring 36 encircles each bolt 35 and its opposite ends react between the block through which the bolt extends slidably and the anchored end of such bolt. The springs 36 will urge all adjacent froe-supporting legs resiliently away from each other.
In the operation of splitting a block B into shake boards, the froes 7 will be held initially in the inwardly and upwardly convergent contracted relationship shown in FIG. 6 by the action of the pneumatic jacks 33 on the rods 31. As the ram head 8 bears against the upper end of the block and forces it downward so that the froes penetrate the block, the shake boards SB being split and consequently the froes 7 will be wedged apart, decreasing their degree of convergent, into the spread relationship shown in FIG. 7. The travel of the ram head is sufficient, as shown in FIG. 7, to push the major portion of the length of the split shake boards endwise down through the spaces between the froes.
When the presser head 8 has been moved downward to its limiting position shown in broken lines in FIG. 2 and in solid lines in FIG. 7, the force exerted by the pneumatic jacks 33 may be reversed to pull rods 31 away from each other if the shake boards have not passed completely down through the froe assembly. The outer legs 26 will thus be spread farther and the springs 36 will spread the adjacent froes away from each other. Such relative spreading will increase the spacing between all adjacent froes to a distance greater than the thickness of the shake boards SB being split, so that such shake boards will fall freely between the froes and be deposited on the discharge conveyor 4.
The reversal of the pneumatic jacks 33 for spreading the froes can be coordinated with the upward retraction of the presser head 8 by ram 10. When the presser head has reached its upper limiting position, the pneumatic jacks 33 may be actuated simultaneously to press rods 31 toward each other again for movement of the froes 7 into the contracted relationship shown in FIG. 6 for placing on them the next block B to be split. The splitting machine will then remain in such condition until the splitterman again presses the foot pedal 22 to initiate a succeeding block-splitting operation of the machine.
The spacer screws 30 of gauge stop blocks 29 will normally be set for splitting of shake boards of minimum thickness such as seven-eighths of an inch. It may be desirable to utilize the shake board splitting machine to split shake boards from which relatively thick shakes can be resawn. Such thick shake boards may, for example, be 11/4 inches in thickness. It is desirable to be able to adjust the shake board splitting machine quickly for splitting such thicker shake boards at will. Such adjustment of the machine can be accomplished by use of the mechanism shown in operative condition in FIGS. 8 and 9. The adjusting mechanism cooperates with the gauge stop blocks 29 to interrupt their contracting movement prior to engagement of the spacer screws 30 with adjacent stop blocks.
The control mechanism for effecting splitting of a block B into relatively thick shake boards includes the double-stepped gauge plate 37 having stop bolts 38 projecting from its steps in positions for engagement by the stop blocks 29 when the stepped gauge plate is in the operative position of FIGS. 8 and 9. Such gauge plate has an aperture through its central portion through which a guide rod 40 extends on which the gauge plate is slidable.
Sliding of the gauge plate between the position shown in FIGS. 6 and 7 and the position shown in FIGS. 8 and 9 is effected by a reciprocable rod 41 having a clevis and embracing a lug 42 projecting laterally from the gauge plate 37. The bifurcations of the clevis and lug 42 are connected together by a pivot pin 43. Reciprocation of the rod 41 is effected by a fluid pressure cylinder 44 the upper end of which has a clevis 45 secured to the machine frame by a pivot pin 46.
When the stepped gauge plate is raised by contraction of the jack 44 to the position shown in FIGS. 6 and 7, the abutment bolts 38 have been moved out of registry with the respective gauge stop blocks 29. When the jack 44 is extended, however, the gauge plate is slid downward so that its abutment bolts 38 are disposed in the path of swing of the stop plates 29 as the jacks 33 push the rods 31 inwardly to move the froes 7 into contracted position. Consequently, contracting movement of the froes will be terminated in the positions shown in FIG. 8 by abutment of the blocks 29 against the bolts 38 instead of the froes moving into the more contracted position shown in FIG. 6.
when a block B is placed on the froes 7 and forced downward by the presser head 8, the froes will be forced apart from the position shown in FIG. 8 to the position of FIG. 9. When the presser head has reached its lower limiting position as shown in this figure, the force of jacks 33 can then be reversed to swing the outer legs 26 still farther outward. The springs 36 again will move the intermediate froes apart as explained in connection with FIG. 7, so that the shake boards will be freed to drop readily between the froes onto the discharge conveyor 4.
While the fluid pressure jacks 33 for contracting the group of froes are shown in FIG. 3 as being supported in substantially horizontal positions by outriggers carried by frame members 47 the block-splitting machine can be made more compact by connecting shorter rods 31 to long upright arms of bell cranks mounted on the frame 6 which are swung by upright fluid pressure jacks engaging relatively short, generally horizontal arms of such bell crank.
In operating the presser head 8 to press the block B for splitting by the froes 7 from the position of FIG. 6 to the position of FIG. 7 or from the position of FIG. 8 to the position of FIG. 9, it may be found that the spreading of the upper ends of the split shake boards as the froes approach such upper ends will be deterred by engagement of such shake board upper ends with the presser head. In such event the resistance of the presser head to spreading of the upper ends of the shake boards can be removed by relieving the downward pressure of the presser head on the upper end of the shake boards one or more times during the full downward stroke of the presser head and then resuming the downward pressure. Alternatively, the lower surface of the presser head 8 could be made of antifriction character, such as by being provided with antifriction roller or ball means.
For many years shakes for roofing and siding have been split one at a time by hand. More recently shake-splitting machines have been used by which shake boards for resawing or finished shakes have been split one at a time. Sawn shingles are sawn one at a time from a shingle block.
The principal object of the present invention is to split a block into a plurality of shake boards in a single pass of the block and splitting froes and to accomplish such operation mechanically.
A further object is to provide such a shake-splitting machine in which a block can be set easily in relationship to splitting froes to produce the best shake boards.
Another object is to provide for automatic removal of split shake boards from the splitting machine.
By provision of a one-pass mechanical shake-splitting machine it is an object to expedite the splitting of shake boards from a block to reduce the labor required to effect such splitting and to produce shake boards which are more uniform and of better quality.
It is also an object to provide a one-pass shake-splitting machine which is of rugged construction yet which is compact and the parts of which are readily accessible for repair or replacement.
FIG. 1 is a plan of a representative arrangement of two single-pass shake-splitting machines according to the present invention which can be operated by a single splitterman.
FIG. 2 is an end elevation of the shake-splitting machine, parts being broken away, and FIG. 3 is a side elevation of such machine.
FIG. 4 is a vertical section through the machine taken on line 4--4 of FIG. 3.
FIG. 5 is a detail top perspective of a portion of a froe and its support showing the parts in exploded relationship.
FIGS. 6, 7, 8 and 9 are enlarged side elevations of the lower portion of the shake-splitting machine showing parts in different positional relationships and having parts broken away.
Two shake-splitting machines of the present invention can, for example, be arranged at opposite sides of a feed table 2 in front of which a splitterman S stands, as shown in FIG. 1. Blocks B to be split into shake boards are supplied to the feed table 2 by a conveyor 3. The splitterman will grasp each block, examine it to determine the position in which it should be placed to be split into the best shake boards SB and slide it into one or the other of the shake board splitting machines 1 in such position. Shake boards SB split from such blocks will fall onto a discharge conveyor belt 4 which will carry the shake boards away from the machine automatically to be stored or to be resawn into shakes.
As shown best in FIG. 4, a block B is slid by the splitterman from the feed table 2 across an apron 5 into the block-receiving chamber of the frame 6. In that position the lower end of the block B is resting on the splitting edges of a plurality of froes 7. The presser head 8 is located above the block in the upper end of the block-receiving cavity. Such presser head is mounted on the lower end of piston rod 9 of a hydraulic ram 10. Such ram is mounted on the upper portion 11 of the machine frame.
Vertical reciprocation of the presser head 8 by the hydraulic ram 10 is effected by controlling the supply of hydraulic liquid to the ram by the valve 12 shown in FIG. 2. Such valve is operated to reciprocate the valve stem 13. The bell crank 14 has an upright arm connected by a link to the valve stem 13. The generally horizontal arm of such bell crank is connected to the actuating rod 15 guided for vertical reciprocation relative to the frame 6. Such rod is reciprocated by a projection 16 carried by the presser head 8 for engagement with upper and lower nuts or set collars 17 and 18 adjustable along the rod 15.
The upper end of the reciprocating rod 15 is received in a friction or holding device 19 which will normally hold the actuating rod 15 in the position to which it has been adjusted. To split the block in the actuating rod is voluntarily reciprocated by swinging lever 20 connected by pivot 21 to the lower end of the rod. Such lever is swung by the splitterman stepping on the end 22 of the lever.
When a block B has been placed in the splitter by the splitterman in the position shown in FIG. 4, the splitterman will step on the end 22 of lever 20 to reciprocate actuating rod 15 upward from the position shown in FIG. 2. Such upward movement of the actuating rod will swing bell crank 14 to reciprocate the stem 13 of valve 12 to the right. Such movement of the valve stem will effect a supply of liquid under pressure to the upper end of ram 10 so that the presser head 8 will be forced downward, first into engagement with the upper end of the block B and then for driving the block through the group of froes 7 until it has reached the broken-line position of FIG. 2.
As the presser head 8 approaches the broken-line position of FIG. 2 or the solid line position of FIG. 7, arm 16 projecting from it will engage the nut or collar 18 on the actuating rod 15 and shift this actuating rod downward for swinging bell crank 14 to move the valve stem 13 to the left. Movement in this direction will be sufficient, not only to cut off the supply of liquid under pressure to the upper end of the ram 10, but also to connect the supply of liquid under pressure to the lower end of the ram and provide for discharge of liquid from the upper end of the ram. The ram will then raise the presser head back to the solid-line position of FIG. 2, at which time the arm 16 carried by it will engage the nut or collar 17 to raise the actuating rod 15 sufficiently to swing bell crank 14 for shifting the valve stem 13 to the right a sufficient distance to center such stem and thereby to cut off the supply of liquid under pressure, both to the lower end and to the upper end of ram 10 for bringing the presser head to a stop in preparation for commencement of the next splitting operation initiated by depressing the end 22 of lever 20 as described above.
As shown best in FIG. 5, each end of each of the froes 7 has an end projection 24 of a size to slide edgewise into an upwardly opening slot 25 in the upper end of a swinging leg 26. The lower end of each such leg is mounted by a pivot pin 27, shown in FIG. 3, extending through a bore 28 in the lower end of the leg. The legs supporting opposite ends of each froe are spaced apart sufficiently to accommodate between them the conveyor belt 4 for removing the shake boards.
As shown in FIG. 6 the splitting edges of the froes 7 engage the end of block B along parallel lines. As the block is pushed endwise against the froes, the tapered cutting edges penetrate the block. Since such cutting edges effect a splitting action on the block rather than a sawing action, no wood is removed from the block. Consequently it is necessary for the split surfaces of the block on each side of a froe to separate a thickness equal to the distance of the froe in order for the froe to continue to enter the block.
Because such spreading action is cumulative across the width of the block, the outer elements of the block transversely of the froes must separate a distance equal to the combined thickness of all the froes. In order for each froe at opposite sides of the center froe or froes to remain in registration with their respective locations of split, therefore, the froes must be spread from the relationship shown in FIG. 6 to that shown in FIG. 7 between the time of initial penetration of the splitting edges of the froes into the block end and penetration of the froes into the block to their locations of maximum thickness. Mounting of the froes on the swinging upper ends of the legs 26, as mentioned previously, enables such spreading action of the froes to occur.
In order to position the froes 7 in the proper contracted relationship for initial engagement by the end of a block B to split it into shake boards of the desired thickness, mechanism is provided to locate the froes in such contracted relationship. Such mechanism includes gauging stop blocks 29 mounted on the several legs in staggered relationship as shown in FIG. 6. In order to enable the position of each froe to be adjusted individually relative to the adjacent froes, a spacer screw 30 is threaded in each gauge stop block and projects from its stop block transversely of the lengths of the legs 26 for abutment with an adjacent stop block. Each spacer screw has a lock nut that can be tightened against the stop block in which the spacer screw is threaded to hold such screw in any desired adjusted relationship.
As is evident from FIG. 6 the spacer screws 30 will only limit approach movement of the froes 7. In order to assure that the froes are held in their contracted relationship when a block B is placed on them, therefore, resilient contracting means are provided to press the froe-supporting legs 26 together. Such contracting means includes presser rods 31 connected by pivots 32 to brackets carried by the outer legs 26 at opposite sides of the froe assembly. These rods are urged yieldingly toward each other by penumatic jacks 33.
In order to be able to effect spreading of the froes 7 without pressing a block B against their splitting edges, mechanical spreading means for the legs 26 are provided. Such spreading means include blocks 34 mounted in staggered relationship on the legs in addition to blocks 29. Each of such blocks is apertured to receive slidably through it a bolt 35 having its length extending transversely of the length of the legs 26. The threaded end of such bolt is anchored by being screwed into a block adjacent to the block through which it extends slidably, and such threaded end is secured in place by a lock nut. A compression spring 36 encircles each bolt 35 and its opposite ends react between the block through which the bolt extends slidably and the anchored end of such bolt. The springs 36 will urge all adjacent froe-supporting legs resiliently away from each other.
In the operation of splitting a block B into shake boards, the froes 7 will be held initially in the inwardly and upwardly convergent contracted relationship shown in FIG. 6 by the action of the pneumatic jacks 33 on the rods 31. As the ram head 8 bears against the upper end of the block and forces it downward so that the froes penetrate the block, the shake boards SB being split and consequently the froes 7 will be wedged apart, decreasing their degree of convergent, into the spread relationship shown in FIG. 7. The travel of the ram head is sufficient, as shown in FIG. 7, to push the major portion of the length of the split shake boards endwise down through the spaces between the froes.
When the presser head 8 has been moved downward to its limiting position shown in broken lines in FIG. 2 and in solid lines in FIG. 7, the force exerted by the pneumatic jacks 33 may be reversed to pull rods 31 away from each other if the shake boards have not passed completely down through the froe assembly. The outer legs 26 will thus be spread farther and the springs 36 will spread the adjacent froes away from each other. Such relative spreading will increase the spacing between all adjacent froes to a distance greater than the thickness of the shake boards SB being split, so that such shake boards will fall freely between the froes and be deposited on the discharge conveyor 4.
The reversal of the pneumatic jacks 33 for spreading the froes can be coordinated with the upward retraction of the presser head 8 by ram 10. When the presser head has reached its upper limiting position, the pneumatic jacks 33 may be actuated simultaneously to press rods 31 toward each other again for movement of the froes 7 into the contracted relationship shown in FIG. 6 for placing on them the next block B to be split. The splitting machine will then remain in such condition until the splitterman again presses the foot pedal 22 to initiate a succeeding block-splitting operation of the machine.
The spacer screws 30 of gauge stop blocks 29 will normally be set for splitting of shake boards of minimum thickness such as seven-eighths of an inch. It may be desirable to utilize the shake board splitting machine to split shake boards from which relatively thick shakes can be resawn. Such thick shake boards may, for example, be 11/4 inches in thickness. It is desirable to be able to adjust the shake board splitting machine quickly for splitting such thicker shake boards at will. Such adjustment of the machine can be accomplished by use of the mechanism shown in operative condition in FIGS. 8 and 9. The adjusting mechanism cooperates with the gauge stop blocks 29 to interrupt their contracting movement prior to engagement of the spacer screws 30 with adjacent stop blocks.
The control mechanism for effecting splitting of a block B into relatively thick shake boards includes the double-stepped gauge plate 37 having stop bolts 38 projecting from its steps in positions for engagement by the stop blocks 29 when the stepped gauge plate is in the operative position of FIGS. 8 and 9. Such gauge plate has an aperture through its central portion through which a guide rod 40 extends on which the gauge plate is slidable.
Sliding of the gauge plate between the position shown in FIGS. 6 and 7 and the position shown in FIGS. 8 and 9 is effected by a reciprocable rod 41 having a clevis and embracing a lug 42 projecting laterally from the gauge plate 37. The bifurcations of the clevis and lug 42 are connected together by a pivot pin 43. Reciprocation of the rod 41 is effected by a fluid pressure cylinder 44 the upper end of which has a clevis 45 secured to the machine frame by a pivot pin 46.
When the stepped gauge plate is raised by contraction of the jack 44 to the position shown in FIGS. 6 and 7, the abutment bolts 38 have been moved out of registry with the respective gauge stop blocks 29. When the jack 44 is extended, however, the gauge plate is slid downward so that its abutment bolts 38 are disposed in the path of swing of the stop plates 29 as the jacks 33 push the rods 31 inwardly to move the froes 7 into contracted position. Consequently, contracting movement of the froes will be terminated in the positions shown in FIG. 8 by abutment of the blocks 29 against the bolts 38 instead of the froes moving into the more contracted position shown in FIG. 6.
when a block B is placed on the froes 7 and forced downward by the presser head 8, the froes will be forced apart from the position shown in FIG. 8 to the position of FIG. 9. When the presser head has reached its lower limiting position as shown in this figure, the force of jacks 33 can then be reversed to swing the outer legs 26 still farther outward. The springs 36 again will move the intermediate froes apart as explained in connection with FIG. 7, so that the shake boards will be freed to drop readily between the froes onto the discharge conveyor 4.
While the fluid pressure jacks 33 for contracting the group of froes are shown in FIG. 3 as being supported in substantially horizontal positions by outriggers carried by frame members 47 the block-splitting machine can be made more compact by connecting shorter rods 31 to long upright arms of bell cranks mounted on the frame 6 which are swung by upright fluid pressure jacks engaging relatively short, generally horizontal arms of such bell crank.
In operating the presser head 8 to press the block B for splitting by the froes 7 from the position of FIG. 6 to the position of FIG. 7 or from the position of FIG. 8 to the position of FIG. 9, it may be found that the spreading of the upper ends of the split shake boards as the froes approach such upper ends will be deterred by engagement of such shake board upper ends with the presser head. In such event the resistance of the presser head to spreading of the upper ends of the shake boards can be removed by relieving the downward pressure of the presser head on the upper end of the shake boards one or more times during the full downward stroke of the presser head and then resuming the downward pressure. Alternatively, the lower surface of the presser head 8 could be made of antifriction character, such as by being provided with antifriction roller or ball means.