US3489188A - Log-turning device - Google Patents

Description

Jan. 13, 1970 M. J. HANSON 3,

LOG NNNNNNNNNNNN CE Filed April 50, 1968 s Sheets-Sheet 1 INVENTOR MARSHALL J. HANSON ATTORNEYS Jan; 13, 1970 M. J. HANSON LOG-TURNING DEVICE 5 Sheets-Sheet 2 Filed April 30, 1968 INVENTOR MARS HALL J. HANSON 351M 00, J m en a morz tgiyv zagow ATTORNEYS Jan. 13, 1970 M. J. HANSON 3,489,188

LOG-TURNING DEVICE Filed April 30, 1968 3 Sheets-Sheet 5 INVENTOR MARSHALL J. HANS ON ATTORNEYS United States Patent O U.S. Cl. 143102 7 Claims ABSTRACT OF THE DISCLOSURE A log-turning device is provided for turning logs on a sawmill carriage. The device includes a toothed endless chain slidably mounted around the periphery of a first lever arm that is pivotally Connected to the sawmill carriage. A second lever arm is pivotally connected tothe carriage at one end and to the chain at the other end, so that pivotal movement of the second arm pushes the first arm about its axis into engagement with a log on the carriage and simultaneously slides the toothed chain around the first arm to turn thelog on the carriage.

This invention relates to a log-turning device for sawmills, and more particularly to a device for turning logs on a sawmill carriage while the carriage is in motion.

In a sawmill, logs to be cut are generally supported on a reciprocating carriage that feeds the logs along the saw line to the saw and then returns to its starting position After a section has been cut longitudinally from one face of the log, the log is turned about its axis to present an other face to the saw so that a further section can be cut from the log.

In the past, the logs have been turned by first returning the carriage 'to its initial position, pushing the log off the carriage onto a log. deck, where a nigger turns the log three-fourths of a turn to place the cut side down, and then returning the log to the carriage. Valuable operating time is thus lost in this method of operation because the mill necessarily remains idle for substantial periods of time while the operators are performing the required turning operation. I It is therefore a primary object of this invention-to provide a new and improved log-turning device that turns the logs on the carriage While it is in motion, whereby the log-turning operation is greatly simplified and expedited, resulting in a more efiicient operation of the sawmill.

Another object of this invention'is to provide a logturning device that is simple and rugged in construction, highly efficient in operation, and that can be readily installed on existing sawmill carriages.

Additional objects and advantages of this invention will be set forth in the description which follows, and in part will. be obvious from the description or may be learned by practice of the invention, the objects and advantages being realized and attained by means ofthe machines, instrumentalities, devices, and combinations particularly pointed out in the appended claims.

To achieve the foregoing objects and in accordance with its purpose, this invention, as embodied and broadly described, comprises a device for turning logs on a sawmill carriage, in which the carriage reciprocates in a direction parallel to the saw line of a saw between a log-charging position and a log-cutting position.

The device includes a first arm to be pivotally connected to the carriage on an axis parallel to the saw line. A chain having log-engaging means spaced at intervals along the chain is slidably mounted around the periphery of the 3,489,188 Patented Jan. 13, 1970 ice first arm. Advancing means pivotally connected to the chain are further provided for rotating the first arm about its axis into engagement with the log and simultaneously for advancing the chain around the first arm to bring the log-engaging means into contact with the log and turn it on the carriage.

In accordance with the invention, the device turns the log one-fourth A) turn on the carriage after each cut to place the cut side down and present a new log face to the saw. Preferably the device turns the log while the carriage is in motion and returning to the log-charging position; so that the carriage can be immediately reversed and returned to the log-cutting position.

In accordance with a preferred embodiment of this invention, the advancing means comprises a second arm to be pivotally connected at one end to the carriage on an axis parallel to and spaced from the first arm axis and at the other end to the chain, and actuating means for pivoting the second arm about its axis in a direction towatdthe first arm to push the first arm into engagement with the log and simultaneously to advance the chain around the first arm.

The accompanying drawings which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention, and together with the descriptioh, serve to explain the principles of this invention.

Of the drawings:

FIG. 1 is a perspective view of a sawmill carriage having the log-turning device of this invention applied thereto;

FIG. 2 is a side elevation showing, in solid lines, the log-turning device of this invention in an at-rest position; and in phantom lines, the device in an extended and operating position;

FIGS. 3 and 4 are schematic views showing the turning of a log with the log-turning device of this invention;

FIG. 5 is a sectional view taken along the line' 55 of FIG. 2; and

FIG. 6 is a left-side view of the device shown in FIG. 2, with the chain removed for clarity.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and'e'xplanatory, but are not restrictive of the invention.

Reference will now be made in detail to the present preferred embodiment of the invention,'an example of which is illustrated in the accompanying drawings.

Logs are conventionally stockpiled on an inclined deck '(not shown) and then fed in sequence onto a reciprocating sawmill carriage 10 that holds and supports the logs while they are being cut. As shown in FIG. 1, a log to be cut is supported on carriage 10 by slides 14, positioned by a plurality of knees '16, and securely held in place by clamps 18. The knees and clamps are adjustable across the'carriage by suitable means 19 so that the log can be advanced towards orwithdrawn from the saw line ofa saw blade (-not shown) to allow the desired thickness of cut to be made in the log. i

The-carriage is then advanced along rails '20 ina direction'parallel to'the saw line, as shown by arrow 22, toward the saw to cut a section orboard longitudinally from one face of the log. 1 As shown in FIG. 1, the present invention provides a simplified log-turning device, generally indicated as' 24, for turning logs on sawmill carriage 10, and more par ticularly to a'device forturning a log one-fourth (V4) turn on the carriage aftera cut has been made in the log. As best shown in FIG. 2, log-turning device 24 includes a first lever arm 34 having a crank arm 36 pivotally mounted to sawmill carriagelfl about axis '38 below the supporting surface of slides 14. Extending around 1 the periphery of arm 34 is a rail 40 (see FIG. for supporting and guiding a chain 42. Chain 42 is conventional, comprising links 44 and rollers 46, the rollers running along the surface of rail 40, while the inside surfaces 48 of links 44 guide the chain along the rail.

In accordance with the invention, chain 42 has a plurality of log-engaging means spaced at intervals along the length of the chain to engage and rotate the log about its axis while the log is on the carriage. As embodied and as shown in FIG. 2, the log-engaging means includes a plurality of spaced dogs 50 having a leading edge 52 that inclines forwardly to provide a barb or tooth 54 that will bite into the periphery of the log and rotate it about its axis. Dogs 50 may form an integral part of links 44 or may be attached to the existing links of a conventional chain.

In accordance with the invention, advancing means are further provided to rotate lever arm 34 about axis 38 and bring it into engagementwith a log while simultaneously advancing chain 42 around the periphery of the arm. As embodied and as shown in FIG. 2, this means includes a slide 56 that is connected to chain 42 and slidably mounted along the underside of arm 34. The advancing means also includes a second lever arm 70 that is pivotally connected to slide 56 at 72 and to carriage about axis 74, the second arm axis being parallel to and spaced from first arm axis 38.

As best shown in FIG. 5, slide 56 has a T-shaped crosssection and includes surfaces 58 that slide along abea'ring plate 60 on the underside of arm 34, and a groove 62 complementary with rail 40 to guide movement of the slide along the arm. A plurality of gussets 64 are provided to strengthen bearing plate 60 with respect to arm 34. A plurality of holes 73 are further provided in slide 56 to permit adjustment of the pivotal connection between arm 70 and the slide.

Actuating means are provided to rotate arm 70 about its axis toward arm 34. As embodied, this means comprises a double-acting pneumatic cylinder 78 having a push rod 78 pivotally connected to lever arm 70 at 80 for raising and lowering the log-turning device in accordance with the objects of this invention.

In operation, pneumatic cylinder 76 is actuated and rotates lever arm 70 in a counterclockwise direction toward lever arm 34. As shown in FIG. 2, rotary movement of arm 70 pushes upwardly on slide 56 and lever arm 34, causing arm 34 to rotate about axis 38 in a counterclockwise direction, as shown by arrow 82, and into engagement with a log on the carriage. Simultaneously, slide 56 is being moved along bearing plate 60 on the underside of arm 34 which causes chain 42 to advance around the periphery of the arm in a clockwise direction and dogs 50 to bite into the periphery of the log. Pneumatic cylinder 76 continues to push upwardly on arm 70 until the device reaches its most extended position, as shown in phantom in FIG. 2.

In operation of a sawmill utilizing the turning device of this invention, and as best shown in FIGS. 3 and 4, an uncut log 84 is placed on slides 14 of carriage 10 and is accurately positioned thereon by knees 16 so that the face of the log is adjacent saw line 86. The operator then lowers clamps 18 to securely hold the log against the knees and advances the carriage to the sawing position removing a board from one face of the log along line 86.

After the log has been cut, the carriage is returned to its initial position, clamps 18 withdrawn to an out-of the-way position, and knees 16 receded slightly, as shown in FIG. 4, to facilitate turning of the log. During the return movement of the carriage, the operator or suitable machine cycling means activates pneumatic cylinder 76 causing lever arm 34 to rotate upwardly and into engage ment with log 84 while simultaneously advancing chain 42 around the periphery of arm 34 in a clockwise direc- 4 tion. As shown in FIG. 4, dogs 50 on'chain 42 bite into the lower part of log 84 raising it upwardly and causing it to turn about its axis in the direction of arrow 88.

Operation of the log-turning device is continued until the log has turned through and the previously cut side is now facedown on the carriage. Log-turning device 24 is then lowered, knees 16 advanced to accurately position a new face of the log with respect to saw line 86, and clamps 18 again lowered to hold the log on the carriage. The sawing and the turning operations are repeated until the log has turned through a total of 270 to provde a log having all four faces removed therefrom.

It will therefore be apparent from the foregoing description that the device of this invention effectively turns the log on the carriage while the carriage is in motion and returning to its starting or log-charging position. The device, therefore, relieves the operator of a great amount of time and efiort that was previously required to perform this turning operation, thereby drastically increasing the efiiciency and economy of the entire cutting operation.

It will also be appreciated that with the device of this invention a separate log-turning device on the log deck as heretofore used is not required to turn the log. Without departing from the scope of this invention, however, suitable means such as a conventional nigger or restraining arm, can be provided on the log deck to push the log back against the knees after it has been turned with the device of this invention in the event that it does not fall in the proper place due to it being out-of-round or having protruding stubs left over from removed branches.

The invention in its broader aspects is not limited to the specific details shown and described, and departures may be made from such details Within the spirit and scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A device for turning logs on a sawmill carriage which is reciprocated between a log-charging position and a log-cutting position in a direction parallel to the saw line of a saw comprising:

(a) a first arm to be pivotally connected to the carriage on an axis parallel to the saw line;

(b) a chain slidably mounted around the periphery of the first arm;

(c) a plurality of log-engaging means spaced at intervals along the chain; and

(d) advancing means pivotally connected to the chain for rotating the first arm about its axis into engagement with a log on the carriage and simultaneously for advancing the chain around the periphery of the arm to bring the log-engaging means into contact with the log and turn it on the carriage.

2. The device of claim 1, wherein the advancing means comprises a second arm to be pivotally connected at one end to the carriage on an axis parallel to and spaced from the first arm axis and at the other end to the chain and actuating means for pivoting the second arm about its axis in a direction toward the first arm to push the first arm into engagement with the log and simultaneously to advance the chain around the first arm.

3. The device of claim 2, wherein the actuating means for rotating the second arm comprises a pneumatic cylinder.

4. The device of claim 2, wherein the log-engaging means comprises a plurality of dogs mounted at intervals along the length of the chain.

5. The device of claim 2, including a slide slidably mounted along one side of the first arm and connected to opposite ends of the chain and to the second arm, whereby pivotal movement of the second arm pushes the first arm about its axis and simultaneously advances the slide along the first arm to advance the chain around th periphery of the first arm.

6. The device of claim 5, which includes adjustment 6 means for altering the location of the connection between References Cited the slide and the second arm.

7. The device of claim 2, in combination with the UNITED sljATEs PATENTS carriage for supporting a log to be sawed, 'wherein said 1,252,894 1918 Fltzgel'ald X first and second arms are pivotally connected to the 2,988,117 4/1959 Lambsofl carriage below the level of the log supported by the car- 5 riage so that pivotal movement of the second arm brings ANDREW JUHASZ, Pnmary Exammef the first arm and the log-engaging means p into engage- JAMES F. COAN, Assistant Examiner ment with the underside of the log.

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