US2661036A

US2661036A - Remote control of sawmill setworks by electromechanical means

Info

Publication number: US2661036A
Application number: US210582A
Authority: US
Inventors: Theodore H Balch; Mark Ray F Van De
Original assignee: SEL SET Co
Current assignee: SEL SET Co; SEL-SET Co
Priority date: 1951-02-12
Filing date: 1951-02-12
Publication date: 1953-12-01
Anticipated expiration: 1970-12-01

Description

6 3 nw l 6 6 .l 2 s K R O WS mm mmm mw HAN Csm LFC AOW amm TnOUE EY T B O M E R 3 Sheets-Sheet l Filed Feb. 12,

Dec. 1, 1953 T, H. BALcH ET AL 2,661,036

REMOTE CONTROL OF SAWMILI.. SETWORKS BY ELECTROMECHANICAL MEANS Filed Feb. l2, 5 Sheecs-Shee?I 2 Dec. 1, 1953 T. H. BALCH ET AL 2,661,036

REMOTE CONTROL OF sAwMILL sETwORKs BY ELECTROMEOHANIOAL MEANS Filed Feb. l2, 3 Sheets-Sheet 3 INVENTORS TheOdOreH'. Ba ICI-1 E Nm 1 OQ WQ bg QN -mmmmmwmdmlmmmw @N50 Y -JMWWWTNNXQ Patented Dec. 1, 1953 REMOTE CNTROL OF SAVVMILL SETWORKS BY ELECTROMECHANICAL MEANS Theodore H. Balch, Salem, and Ray F. Van De Mark, West Salem, Oreg., assignors, by direct and mesne assignments, to Sel-Set Company, West Salem, Oreg., a corporation of Oregon Application February 12, 1951, Serial No. 210,582

' 23 claims. Vl o1. 143-120) This invention'pertains to setworks, and relates particularly to the novel construction of a sawmill setworks by which the operation of a sawmill carriage assembly maybe controlled from a remote position.

, There are many types or" machines in each of which the fundamental basis of operation involves the relative adjustment between a work support and a cooperating working tool. In some machines this adjustment is aforded by movement of the Work support relative to a fixed working tool, while in other machines the working tool is adjustable with respect to a xed Work support. Still other machines provide ior movement of boththe work support and the working tool. In general, such movement of working parts is -achieved by the rotation, i. e. angular displacement, of a driven shaft, and it is to this type of machine that the present invention isy applied with particular advantage.

For purposes merely of illustration the present invention is described hereinafter with particular reference to sawmill setworks. Since, as eX- plained hereinbeiore, various other types of machines operate upon the same basic principle, the

specific reference to sawmill setworks is not intended as a limitation upon the scope of this invention.

Briefly, the construction and operation of a conventional sawmill carriage assembly is as follows: The carriage is a wheeled framework supported upon spaced rails which guide the carriage back and forth past a powered saw. The carriage includes a plurality of spaced head blocks upon which to support a logintended to be sawed into boards. Retractible dogs secure the log releasably in abutment with kneesgwhich are mounted slidably upon the head blocks and coupled to a power driven set shaft through lead v screws or knee chains. By selective rotation of the set shaft, as controlled by the operator, the knees, and hence the log, are moved forward or rearward with respect to the saw.

The selective control-of theset shaft is achieved by means of setworks, many types of which are well-knovvn in the art. Howeven there is a fundamental principle of operation common to all of. these prior setworks, namely, they are mounted upon and are required to be operated from the moving carriage.v Thus, it is necessary that the operator be stationed upon and ride with the carriage in order to operate the setworks of the prior art. This arrangement is not only uncomfortable for the operator-but it also exposes him to the extreme hazards of ying parti- 2 cles suchas occurs, `not infrequently, with the breakage of a saw blade.

Itis a principal object of the present invention,

therefore, to provide a setvvorks whereby the operation of the sawmill carriage assembly may be controlled from the safety of a remote position.

Another important object of this invention is the provision of a setworks in which adjustment for each. succeeding cut of the log is made merely by pressing properly identified push buttons. By this provision thel linearfootage production of lumber from the mill is increased substantially and possible error in adjustment is completely obviated.

A further important object of the present invention is the provision of a setworks which afords complete control of the sawmill carriage assembly by but oneoperator, thereby obviating the loss `of time and the presentation of hazards lordinarily attending the loperation of a carriage byacrew.

A still further object of this invention is to provide a setworksfconstructed of a minimum of parts, which is sturdily built for long operating life and which is capable of effecting rapid and precise adjustment of the set shaft.

A'general'object of this invention is the provision of a device for controlling from a remote position the 'selective' angular-displacement of a rotary shaftf `These and otherobjects and advantages of the present invention`v will appear from the following detailed description'taken in connection with the accompanying drawings, in which:

Figure l'is a fragmentary plan view of a sawmill showing incorporated therewith a setworks embodying the features of the present invention; I"Figure 2 -is a 'front elevation of the setworks illustrated vgenerallyin Figurejl with the front case panel, removed to expose the operating parts;

Figure is an end View of the setworks as viewed from thev right in Figure 2, parts lbeing broken away to disclose details of construction;

Figure 7 is a sectional View taken along the line 'I-I in Figure 5; and

Figure 8 is a schematic diagram of the electrical control circuits of the setworks; and

Figure 9 is a foreshortened fragmentary schematic diagram illustrating an alternative arrangement for interconnecting the setworks control and the set shaft drive motor.

Referring particularly to Figure 1 of the drawings, there is shown for purposes of illustration 'i the general details of one form of conventional sawmill. The sawmill includes a log 2deck upon which logs I are deposited, as from a millpond, preparatory to cutting. The log deck comprises the spaced deck skids 2, the cradle type stop and loaders 3 secured to the 'shaft `4 andthe log loaders 5 secured to the shaft 6. The shaftsvd and 6 are driven by motor means (not shown) in manner well-known in the art.

Adjacent the forward end of the log deck and extending perpendicularly with respect thereto is a pair of spaced parallel rails 'I. A'logcarr'iage framework 8 is supported `upon therails by 4wheels 9 and is drawn forwardly and rearwardlythereon by cables Il] and II, respectively, each of'w'hich is secured at one end to the framework and :at the other end to a power winch (not shown).

Extending transversely of rthe carriageframework are spacedhead blocks I2 upon whicha log I is deposited from the log deck. An upstanding Vknee I3 is supported slidably upon each head block for longitudinal movement over-the latter. The knees are'connected to a power driven .setshaft I4byA anyconventionalmeanssuch as the lead screws I5 or knee chains. The set shaft extends longitudinally ofthe carriagel and is journaled inY bearings I6 .supported by the head `blocks I2 `and bythe intermediate frame members I1, I8. In the carriage-assemblyillustrated the set shaft is driven by meansxof an air motor I9 mounted upon theframe member I1. 'The motor is coupled to the set shaft by chain reeved over sprocket wheels 2 I .and 22 secured, respectively, to the drive shaft 23 of the motor I9 and to the set shaft I4. It will be apparent to those `skilled in the art that an electric or other type of drive motor may be substituted forthe air motor illustrated and that various other ytypes of coupling 4means `may be employed, as desired,

Thel log I is arranged upon the fhead blocks I2 f in abutment with the knees I3 and issecured releasably in-that position by the `retractable dogs 24 mounted in the knees. `In this manner the log l is renderedmovable with .the knees, as the latter are actuated by rotation of the set shaft. I4.

A saw blade 25 is arranged ladjacent the for-t ward rail insuch manner as to clear the head blocks I2 as the carriage is moved along the rails. The saw blade illustrated yin Figure v1 isof the circular type mounted upon `an arbor 26 which is driven by motor 21. It will be understood by those skilled in the art that other types of saw blades, such as the band saw blade, may beem- .ployed as desired.

prior art are mounted upon the movable carriage, thus making it necessary for the operator to ride with the carriage. It is a particular advantage, on the other hand, that the setworks of the present invention may be operated from a remote position with respect to the carriage, as explained v"in detail hereinafter.

In Figure 1 of the drawings the operating Vmechanism of the present setworks is illustrated generally by the case 30 mounted upon the inbores 40 varranged in` axial alignment. A selfaligning bearing 4I `is mounted 'in the transverse bore of each standard. `A shaft42is `supported adjacent its ends for axial rotation in the bearings 4I. As best shown in Figure 5, the shaftterminates V'within thefbore of standard, whilethe opposite end of the shaft extends outwardly through a hole providedin the side panel 34. The outer end of the transverse bores are provided With ydust seals 43.

Secured to the standard 38 `by bolts 'isa Adisc 45. The hub 46 vof the disc is provi'dedwith a ltransverse bore -41 Ioflarger diameterthan'the shaft 42, whereby to receive the latter freely therethrough. A second disc'48 `havingatransversely bored hub y49 is mounted for freeV rotationv about shaft 42 upon the spacedbearings 5I). 'I'he discs `45 and 48 are arranged Tiri'spaced cooperativeirelation for purposes explainedindetail-hereinafter.

A hollow housing 5I is secured at its hub 52 to the hub 46 ofthe fixed disc 45`f'by 'set screw 53. The rim of 'the housing projectstoward the rotary disc 4B and overlaps a portion of the rotary disc hub 49 in spaced concentric relation; A helical `spring 54 is secured at its inner'end to the rotary disc hub 49 as by bolt 55. The outer end 56 of the spring is bent radially outward' andis received withina slot 51 formed in the rim `ofthe housing, as best shown=in Figui-ei?. By this arrangement of` the spring 54, the hubl 49, and therefore `the rotary disc A4Ii, is 'urged to rotate intal counterclockwise direction as viewed ,in`- Figure 7. The extent of this counterclockwise `rotation is restricted by `the'provision `of a bar 5B secured to the disc 48 by screws 59 and arranged to abut against-.the'bumper 6l) mounted 'upon the bottom ofthe case. When `in'this condition of abutment, kthe setworks is -inV its normal, unenergized position of rest.

A clutch drum 6I issecuredatitshub 62-to shaft 42 lby set screw 163. TheY drum is disposed adjacent the rotary disc 4B onithe side thereof opposite the .spring housing 5I. A'c'lutch band 64 encompasses the drum 6|,"the free ends of the band' being secured pivotally through the'couplings and'pins 66'to'one end of the spaced rocker arms 61. The rockerfarmsare mounted pivotally intermediate their ends upon the spaced pivot pins `6Iisecured to the rotary disc;

A cam arm 63 is mounted pivotally atene end upon pin I0 secured to the rotary `disc 48. This pivoted end of 'arm 69 is formed with alaterally projecting cam 'Il of oval shape. Thecam is disposed between the spaced rocker arms for abutment with the latter adjacent the ends opposite the couplings 65.

The end of cam arm 69 opposite the cam 1I is connected pivotally through the adjustable link 12 to the plunger 13 of the solenoid 14. The solenoid is secured to the rotary disc 48 by spaced bolts 15. A coil spring 15 surrounds the pvoted end of cam arm 59 adjacent the cam 1| and is secured adjustably at its opposite ends in slots formed in the rotary disc 48 and the arm 69, respectively, as best shown in Figure 5. This coil spring functions upon deenergization of the solenoid 14 to withdraw the plunger 13 and release the clutch, as fully explained hereinafter.

A collector ring 11 of electrically non-conducting material is received about the shaft 42 through its enlarged central opening 18. The ring is secured to the rotary disc 49 by the circumferentially spaced bolts 19. The rotary disc and collector ring are held in spaced relation by the spacer tubes 83 mounted upon the bolts 19 intermediate the ends thereof. By the foregoing construction the collector ring is caused to rotate with the rotary disc 48.

Mounted upon the non-conducting collector ring is a pair of electrically conducting contact rings 8| and 82 arranged in spaced concentric relation. A terminal screw 83 is secured to each contact ring and extends through the collector ring 11. The terminal screws function to connect the conductors 84 and S5 leading from the clutch solenoid 14 to the respective contact rings 8| and 82.

Sliding electrical contact with the contact rings is made by such means as the conventional spring-loaded carbon brushes 86 mounted within the central hollow portion of the standard 39. The electrical conductor wires 81 and 88 connecting the brushes extend laterally through the standard 39 to a terminal block 89 mounted upon the case. The central open portion of the standard is sealed by the removable plate 90.

Referring now particularly to Figures 4 and 5 of the drawings, the upper half of the fixed disc 45 is provided with concentric arcuate slots 9| extending transversely thereof and curved about the axial center of shaft 42. The circumferential slots are preferably interrupted at spaced intervals to form structural ribs 92 which function to reinforce the disc 45. rEhe ribs of adjacent concentric slots are preferably staggered radially, as shown in Figure 4, for purposes explained hereinafter.

A plurality of

micro switches

53, 94, 95, 96 and 91 are supported by their lateral, threaded eXtensions 98 in the arcuate slots 9| of disc 45. These lateral extensions extend slidably through the slots and are secured releasably by the lock nuts 99. In this manner each micro switch may be secured in any desired position within the lcrcumferential limits of the arcuate slots. Where a rib 92 prevents the proper mounting of a micro switch in one circumferential slot, the adjacent concentric slot is available. The spring-loaded contact buttons |00 of the micro switches project outwardly from the ends of the lateral extensions 98.

The terminal connectors I Ill of the micro switches are connected by conductor wires (not shown) to the terminal block 99 mounted upon the case.

The rotary disc -18 is also provided with concentric arcuate slots |92 curved about the axial center of shaft 42 and preferably curved upon the same radii as the respective slots 9| in the fixed disc 45. The length of the slots |02 need be only a fraction of the length of the slots 9|, however. Mounted adjustably in the arcuate slots |02 are the finger cams |83 and |4. The connecting end of each of these cams comprises a cylindrical end portion, having a diameter substantially equal to the width of the arcuate slot |92, and an intermediate shoulder portion |05. The cylindrical end is received slidably in the slot with the shoulder |05 abutting against the face of the rotary disc d8. A bolt |06 (Figure 3) is then threaded into the cylindrical end to abut against the disc face opposite the shoulder IE5. The cams |03 and |04 are of substantial width and are each curved about the axial center of the shaft 42, as best shown in Figure 6.

The nger cams are arranged to engage and depress each of the contact buttons |00 of the several micro switches as the rotary disc 48 is caused to rotate, as explained in detail hereinafter. Thus, the nger cam |93 actuates micro switches secured in the outer circumferential arcuate slots, while the inner finger cam |04 actuates micro switches secured in the inner circumferential slots. In the arrangement illustrated in the drawings and best shown in Figure 4, the finger cam |93 actuates the

micro switches

93, 94, 95 and 91 while finger cam |04 actuates micro switch 96.

It is to be noted here that micro switch 93 is arranged in such manner that its contact button |09 is depressed by nger cam |03 when the rotary disc 98 is at its rest position, i. e. when the bar 58 is in abutment with the bumper S0. This micro switch is hereinafter referred to as the safety micro switch. The safety micro switch is closed when engaged by the finger cam |03, whereas the remaining micro switches are opened when engaged by the finger cams.

It is to be noted further that the number of micro switches to be mounted in the arcuate slots 9| is dependent upon the number of different sizes of boards to be cut, as explained in detail hereinafter.

Referring now to Figure 1 of the drawings, the freely rotating shaft 42 projects at one end through the case 39 mounted upon the carriage frame I8, as explained hereinbefore. Secured to this projecting end of shaft 42 is a sprocket |01 which is coupled through chain |09 to sprocket |09 mounted upon the reduced end of drive shaft 23 of the set shaft air motor I9. By virtue of the positive coupling between the knees I3 and the set shaft |4, as afforded by the lead screws I5, there is established a denite relationship between the linear distance through which the knees travel per revolution of the set shaft. Accordingly, since the set shaft is coupled through the drive shaft of the air motor I 9 to the shaft of the setworks mechanism, there is established a definite relationship between the linear movement of the knees per degree of rotation of the setworks shaft d2. Thus, for example, with the safety micro switch 93 in the normal rest position shown in Figure 4., the angles formed from the axial center of shaft 42 between the safety micro switch 93 and the respective micro switches 913, 95, 9G and 91 represent forward movements of the knees of 3, 4, 5 and 6 inches, respectively.

Mounted upon the moving carriage is a reference dial I I9. This dial is mounted upon shaft |I| journaled for rotation in bearing i i2 secured to an upright support of the carriage. A sprocket wheel ||3 secured to shaft III is connected through chain I |4 to sprocket wheel I5 mounted upon the set shaft I4. An index pointer IIB vis mounted upon the upright support for bearing ||2 for registry with the dial ||0. By proper selection of sprocket wheels ||3 and ||5, the indicated graduation on the reference dial under the index pointer identifies the number' of inches separating the knees I3 and the plane of the saw blade 25.

In Figure 1 there is shown a forward limit switch I |1 and a reverse limit switch I I8 mounted upon elements of the carriage framework adjacent the right-hand knee I3. These switches are arranged in the circuits of the drive motor controls, as shown in Figure 8. A finger ||9 projecting laterally from the knee is arranged to contact the forward and reverse limit switches at the extreme opposite limits of travel of the knees. Thus, upon contact of the linger I I9 with leither switch, the circuit to the drive motor I9 is opened and rotation of the set shaft I4 is stopped. In this manner the linear travel of the knees is restricted to the length of the head blocks I2 or to any shorter distance desired.

The terminal block 89 mounted upon the case 30 functions as a detachable coupling for the electrical conductors extending between the .mechanism contained Awithin said case and the mechanism mounted externally thereof. These conductors, omitted in Figure l to avoid encumbering the view but illustrated diagrammatically in Figure 8, lead from the case to the setworks control panel |20.

The control panel is located conveniently between the log deck and the saw blade 25, and is preferably arranged slightly forward of but between the spaced levers |2| by which the operator controls the movements of the log deck and carriage assembly from his position in seat |22.

The setworks control panel |20, the levers I2I and seat |22 may be shielded, if desired, by the protective walls indicated by the dotted lines |23 to insure the operator against injury from flying particles.

Mounted in the top of the control panel |20 are a plurality of electrical push button switches by which the operation of the setworks mechanismis controlled by the operator. These push buttons are shown in Figures 1 and 8 as beingseven in number to accommodate the cutting of logs into the four different dimensions of boards exemplied hereinbefore. rEhe function and operation of the push button switches are described in detail hereinafter.

The forward relay coil |3| is connected from the volt supply line |21 through the forward knee limit switch I I1, through the normally open forward push button switch |31 and the normally closed stop push button switch |38 to the 110 volt supply line |28. In similar manner, the reverse relay coil |34 is connected from supply line |21 through the reverse knee limit switch ||8, through the normally open reverse push button switch |39 and the normally closed stop push button switch |38 to supply line |28. In accordance with well-known practice, the breaker contacts of the forward and reverse relay coils are interlocked mechanically, as indicated by the broken line |40, to prevent their simultaneous actuation.

Upon energization of the safety relay coil |4I, the holding contact |48 is closed to complete a circuit arranged in parallel with the control push button switches |43 to |46, inclusive, by line |49. In this manner any of the latter switches may thereafter be depressed without opening the circuit of the safety relay coil |4I.

Energization of the safety relay coil also closes the contact |50 which completes the circuit of any one of the said control push button switches when in the depressed position. For example: The circuit of the depressed control push button switch |43 is completed from supply line |28 through the stop switch |38, through the normally closed interlock contact |5I, through the closed safety contact |50 and depressed push button switch |43, and thence through the control relay coil |52 to supply line |21.

Upon energization of the control coil |52, the normally open contacts |53, |54 and |55 are caused to close. The closing of holding contact |53 completes a circuit through the normally closed micro switch 94 arranged in parallel with the seriesl combination of the interlock ycontact |15I, the safety Contact |50 and control push button switch |43. The closing of contact |54 completes a `circuit from supply line |21 through the forward relay coil |3| and forward knee limit switch ||1 to supply line |28. The closing of contact |55 completes a circuit through the clutch solenoid 14 arranged in parallel with the series combina-tion of `the micro switchv 84 and control coil |52. Thus, the depressing of control push button |43 causes energization of the control relay coil |52 which closes the contacts |53, |54 and |55 to energize the forward relay lcoil |3| and the clutch solenoid 14.

n In the manner of the foregoing description, depressing control push button 44 causes activation of control relay coil |56 which closes contacts |51, |58 and |59 to energize the forward relay coil |3| and clutch solenoid 14; depressing control push button |415 energizes control relay coil |60 which closes contacts |6|, |62 and |63 to energize the forward relay coil |3| and the clutch solenoid 14; and depressing control push bu-tton |46 energizes control relay coil |64 which closes contacts |65, |66 and |61 to energize the forward relay coil |3| and clutch solenoid 14.

It is to be observed here that the closing of either the forward push button switch |31 or the reverse push button switch |33 does not activate the control relay coils nor the clutch solenoid 14. In addition, it is to be noted that the closing of the reverse push but-ton switch |39 completes a circuit from supply line |21 through the interlock relay coil |68, through the reverse knee limit switch H8 and the depressed reverse push button switch |39, thence through the normally closed stop push button switch |36 to supply line |28. rI'hus, when 4the reverse push lbutton switch is closed to energize the reverse relay coil |34, the interlock relay coil |68 is also energized and the interlock contact |5| is opened to break the circuits of all of the control push buttons for their depressed positions. This arrangement insures against the energization of the clutch solenoid when the knees |3 are being retracted, and thereby prevents possible damage to the setworks mechanism.

As explained hereinbefore, the closing of the holding contacts |53, |51, |6I and |65 completes circuits through the respective

micro switches

94, 95, 96 and 91 which shunt `the respective control push button switches |43, |44, |415 and |46. Thus, the normally closed micro switches main tain their respective control relay coils energized after the control push button has been released. It is evident, therefore, that lthe control relay coils will become deenergized when their respective micro switches are opened upon contact of the finger cams |03 and |64.

The operation of the setworks described hereinbefore is as follows: Let it fbe assumed, for purposes of this description, that vthe operator contemplates the cutting of logs into the various dimensions of 22/3, 32/3, 42/3 and 52/3 inches, and that the width of the saw blade 25 is one-third inch. Since the width of the saw kerf must be accounted Ifor in each cut, the respective forward movements of the knees necessary to produce the above desired cuts are 3, 4, 5 and 6 inches. Assume further, therefore, that the mirco switches 94, 95, 96 and 91 have been secured in the arcuate slots 9| of lthe xed supporting disc 45 n such manner that their respective angular displacements with respect to the safety micro switch 93 represent forward linear movements of the knees on the head blocks of 3, 4, 5 and 6 inches.

Assume further that the knees are presently disposed closely adjacent the plane of the saw blade and therefore must be retracted preparatory to the deposit of a log upon the head blocks. By visual inspection the operator estimates the diameter of the log to be abo-ut three lfeet. Accordingly, since the knees are to be retracted, the operator, stationed at the seat |22, depresses the reverse push `button |39 mounted upon the control panel |20.

The closure of the reverse push button switch completes the circuit of the reverse relay coil |34 which thereupon becomes energized to close the breaker contacts |32, |33 and |36. The 110 volt -circuits of the respective reverse and exhaust solenoids |25 and |26 are thereby energized and the air motor i3 is operated to rotate the set shaft |4 in the direction for retracting the knees. The setworks shaft 42 rotates with the set shaft, as previously explained.

Simultaneously with the foregoing energization of the reverse relay coil |34, the closure of the reverse push button switch |39 closed the circuit of the interlock relay coil |68. The interlock contact 5| is thereby opened to prevent accidental energization of the clutch solenoid 14. It is apparent that should the clutch =band 64 become engaged with the clutch drum 6| while the latter is rotating in the reverse direction. serious damage to the setworks mechanism might oe sustained.

While maintaining the reverse push button switch closed, the operator watches the reference dial ||0. Then, as the numerical value of thirtysix inches on the said dial registers with .the index pointer .I I6, the operator releases the reverse push button. The reverse relay coil |34 is .thereby d-eenergized, the breaker contacts |32, |33 and |36 open the 110 volt supply lines of the respective reverse and exhaust solenoids |25 and |216, and the air motor |9 is stopped. The knees have thus been retracted to a position thirty-six inches yfrom the plane of the saw blade, as desired.

With the carriage arranged in position adjacent the log deck, the operator now manipulates the levers |2| to deposit the log upon the head blocks and to secure it in positive abutment with the knees, in conventional manner.

Let it now be assumed that it is necessary to draw the log forwardly i. e. toward the plane of the saw blade in order to make the initial slab cut. Accordingly, the operator depresses the forward push button |31. This energizes the forward relay coil |3| which closes the breaker contacts |29, |30 and |35 in the 110 volt supply lines of the respective forward and exhaust solenoids |24v and |26 of the air motor I9. The set shaft I4 rotates and draws the knees and log forwardly. When sufficient thickness of log has been drawn across the plane of Ythe saw blade to make the desired slab cut, the operator releases the forward push button |31. The air motor is thereby deactivated, the rotation of the set shaft is stopped and the forward movement of the log is halted.

By manipulation of the levers |2| the operator moves the carriage forwardly upon the rails 1, whereby the saw blade engages the log and makes the desired slab cut. The operator now manipulates the levers |2| to draw the carriage rearwardly to its initial starting position. Assume the the operator repeats the foregoing procedure after turning the log through successive stages to remove the four quadrant slab cuts and produce a square cant, the forward edge of which lies on the plane of the sawblade. Assume further that the Value of 28 inches on the reference dial |0 registers with the index pointer I6. This indicates to the operator that the thickness of the cant is 28 inches.

Let it now be assumed that the operator wishes to cut from the square cant a board having a thickness of 4% inches. Since, in thisv example, the width of the saw blade isone-third inch,the

total forward movementoffthe knees required for producing this board is ve inches. This dimen- 11 sion corresponds to the angular position of micro switch 96 relative to the safety micro switch 93. Since micro switch 96 is arranged in the circuit of the control push button switch |45, the operator will depress the latter for moving the knees |3 forwardly a distance of ve inches.

Prior to depressing the control push button |45, the electrical system is in the condition shown in Figure 8. In this condition the safety micro switch 93 is closed by virtue of its contact with the finger cam |03, the rotary disc 48 being at its normal rest position with bar 58 in abut* ment with the stop 60. With the safety micro switch 93 closed, the safety relay coil |4| is energized and the contacts |48 and |50 are closed.

The closure of contact |63 completes a circuit from supply line |28 through the stop push button switch |38 to collector ring B2, through the clutch solenoid 14 to collector ring 8|, and thence through contact |63 to supply line |21. The clutch solenoid is thereby energized and the solenoid plunger 1.3 is drawn downwardly. Cam arm 69 is thus caused to swing downwardly and pivot the cam 1| in a counterclockwise direction. The cam thereby forces the rocker arms 61 apart at their upper ends and draws the lower ends together. The clutch band 64 is thus caused to be tightened upon the clutch drum 6|.

Simultaneously with the activation of the brake solenoid 14 the closure of contact |62 completes the circuit of the forward relay coil |3|, as previously explained. The breaker contacts |29, |30 and |35 are thereby closed and the air motor i9 is activated to rotate the set shaft in the direction for movingl theknees forwardly toward the plane of the saw blade.

By. virtue of the positive coupling between the set shaft I4 and the setwcrks shaft 42 through the drive. shaft 23 of the air motor, the setworks shaft rotates simultaneously with the set shaft. Thus, since the clutch band 84 has been tightened upon the clutch drum 6|, the rotary disc 48 is caused to rotate simultaneously with the setwcrks shaft 42 and set shaft I4.

As the knees progress forwardly, the rotary disc 48 turns in a clockwise direction, as viewed in Figures 3 and 7 of the drawings. The finger cam |03 mounted upon the rotary disc is thereby rotated out of engagement with the spring-loaded contact |00 of the safety micro switch 93, whereupon the latter. opens andV breaks the circuit of the safety relay coil I4|. Deenergization of the safety relay coil causes the contacts |48 and |50 to open. The opening of contact |50r breaks the circuits of the control push button switches for their depressed positions and thereby renders the latter incapable of energizing their respective cooperating control relay coils. I'his arrangement prevents the activation of the control relay coils by the control push buttons until the operating cycle presently in progress is completed.

The circuit of the control relay coil |60 is now respectively, had not previously been energized and therefore no action results. A

When finger cam |04 rotates into engagement with the spring-loaded contact of micro switch 96, the set shaft has caused the knees to be moved forward upon the head blocks a distance cf five inches. Upon engagement of the finger cam |04 with micro switch 96 the latter is opened and the corresponding control relay coil |60 is deenergized. Contacts |6|, |62 and |63 thereupon open immediately to deenergize the forward relay coil |3| and clutch solenoid 14 as explained hereinbefore.

The deenergization of the forward relay coil |3| causes the breaker contacts to open and deactivate the respective forward and exhaust solenoids |24 and |26 of air motor I9. The closing of the motor exhaust port functions to brake the motor to a rapid stop, as is well-known in the art. The rotation of the set shaft |4, the setwcrks shaft 42 and the rotary disc 48 is thereby halted.

Simultaneously with the deenergization of the forward relay coil |3|, the clutch solenoid 14 is also deenergized. It is to be noted here that during the counterclockwise rotation of the cam 1| in tightening the clutch band 64 about the drum 8|, as described hereinbefore, the coil spring 'i6 was also tightened. Accordingly, upon deactivation of the solenoid the coil spring 16` l, `frein the solenoid and the cam 1| returns to its normal state to release the clutch band from engagement with the clutch drum.

Referring particularly to Figure 7 of the drawings, it is to be noted that, during the foregoing `-clockwise rotation of the disc 48 which moved finger cam |04 into engagement with micro switch 96, the spiral spring 54 was tightened. Accordingly, when the clutch solenoid 14 becomes deenergized and the clutch band is disengaged from the clutch drum, the spring 54 is free to return from its tightened state to a more relaxed condition. In returning to this more relaxed position, the spring causes the disc 48 to be ro,l

tated in a counterclockwise direction until the bar sa comes into abutment with the stop so.'

The tension of spring 54 may be adjusted within rather wide limits by loosening the set screw 53 and rotating the housing 5| in the proper direction until the desired tension is obtained. The

set screw is then tightened into engagement with the hub 46 of the fixed disc 45.

The rotary disc has thus been returned to its normal rest position, and finger cam |03 has returned to engage and close the safety micro switch 93. lThe operating cycle of the setwcrks has now been completed, with the knees having been moved forwardly toward the plane of the saw blade a distance of nve inches.

The operator observes that the numerical value on reference dial ||0 now registering with the index pointer ||6 is 23 inches. Since the prior reading was 28 inches, the operator is assured that the desired setting has been properly made.

The operator now manipulates the levers |2| to move the carriage forward over the rails 1 and thus to cut the board from the cant, after which the carriage is returned in the manner previously explained;

`In the event the operator desires to cut several more boards of 4% inch thickness, he merely depresses the same control push button |45 to repeat the cycle described hereinbefore. On the other hand, if it is desired to cut boards of either 22/2v 32/3. or 52/3 inch thicknesses, the operator merely depresses the appropriate control push button |43, |44, or |45, respectively. The operating cvcle for any of these is the same as the cycle previously described.

It is to be noted here that should theoperator maintain the reverse push button |39 depressed for a time sufficient to draw the knees rearwardly to their extreme limit, the finger H9 carried by the right-hand knee will engage and open the reverse limit switch ||8. switch breaks the circuit of the reverse relay coil |34 and thereby results in the deactivation of the air motor i9. Thus, the rotation of the set shaft ceases and the rearward travel of the knees is halted. In similar manner, excessive forward travel of the knees by depression of the forward push button |31 or any of the control push buttons is restricted by the opening of the forward knee limit switch I1.

From the foregoing detailed description of the construction and operation ofv the setworks illustrated, it is believed apparent that those skilled in the art, will recognize the many advantages of the present invention. When employed as setworks in sawmill operation ,the required settings of the knees are made rapidly with precision and with the facility of push button control. Lumber production is substantially increased while the requirement for operating personnel is reduced to a single sawyer. Complete operating safety is afforded by removal of the push button control panel to a position remote from the carriage.

It will be further apparent to those skilled in the art that the Ypresent invention is readily adaptable for use with other than sawmill apparatus. In general, the present invention is capable of controlling the angular displacement or rotation of any shaft or other device driven by an electrically controllable motor. Thus, for example, the reference dial may be graduated in degrees to designate the angular rotation of a rotary shaft.

Various changes in the structural details illustrated and described hereinbefore may be made without departing from the scope and spirit of this invention. For example, it is evident that the positions of the micro switches and their actuating finger cams upon the fixed support 45 and rotatable disc 48, respectively, may be reversed, i. e. the switches may be mounted upon the rotary kdisc i3 and the cams mounted upon the fixed support. The types and relative positions of other cooperating elements may also be changed in accordance with recognized practices.

It is to be noted that a plurality of micro switches are illustrated in the drawings and have been described hereinbefore as each providing for a different angular displacement of the set shaft and, hence, a different forward setting of the knees'. Those skilled in the art will recognize that but one micro switch need be provided and that it may be adjusted circumferentially with respect tothe rest position of the finger cam to establish different angular displacements. The structure illustrated is preferred, however, because it provides a number of dierent settings each of which is immediately available for use merely by depressing the proper control push button switch.

Although the setworks case and the mechanism housed therein is shown in Figure 1 as being The opening of this mounted upon the carriage adjacent the driveV motor I 9, it is to be understood that the unit may be removed to a position remote from the carriage as, for example, adjacent the control panel |20. In such cases, coupling between the drive shaft 23 of motor I9 and the control shaft 42 of the setworks may be made by means of Selsyn motors or other equivalent servo-type system in the manner described in detail in our copending application, Serial No. 210,581 filed concurrently herewith and entitled Remote Control Setworks. This type of arrangement is i1- lustrated in Figure 9 wherein the drive shaft 23 of motor I9 is connected by flexible coupling |10 to the drive shaft |1| of the master Selsyn motor |12. Wires |13 interconnect the master Selsyn and a slave Selsyn |14 whose drive shaft |15 is connected through the exible coupling |16 to the shaft 42 of the setworks control mechanism contained in the case 3i).

In view of the foregoing and other -apparent changes, it is to be understood that the detailed description set forth hereinbefore is merely i1- lustrative and is not to be considered in a limiting sense.

Having thus described our invention and the manner in which the same may be used, what we claim as new and desire to secure by Letters Patf ent is:

1. A device for controlling the angular displacement of a rotary shaft powered by an electrically actuated motor, said device comprising, in combination with an electrical supply for actuating the motor; a control shaft adapted to be coupled to the rotary shaft for simultaneous rotation therewith, a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electricallyactuated coupling means releasably interconnecting the rotatable support and the control shaft, first switch means mounted upon one of the supports and arranged in the circuit of the motor and coupling actuating means, switch-actuating means mounted upon the other supportl in angular displacement with the switch means when the rotatable support is in rest position, the switch and switchactuating means being disposed for mutual contact upon a predetermined rotation of the rotatable support, control switch means in the circuit of the motor and coupling actuating means for activating the motor and coupling means simultaneously to rotate the rotary shaft and the rotatable support, the first switch means functioning upon engagement of the switch-actuating means to deactivate the motor and coupling means, whereby to stop the rotation of the rotary shaft after the latter has rotated through the angle selected by the control switch means, and means independent of the motor for returning the rotatable support to its rest position after rotation.

2. A device for controlling the angular displacement of a rotary shaft powered by an electrically actuated motor, said device comprising, in combination with an electrical supply for actuating the motor; a control shaft adapted to be coupled to the rotary shaft for simultaneous rotation therewith, a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasably interconnecting the rotatable support and the control shaft, a plurality of first switch means mounted upon one of the supports and each arranged in the circuit of the motor and coupling actuating means, switch-ac accross i5' tuating meansmounted upon the other support., the angular. displacement. between the switchactuating means and each first switch means when the rotatable support is in rest-position being proportionate to a corresponding angular displacement of the rotary shaft, a pluralityA of control switch means each arranged in the cir-l cuit of the motor andcOupIing actuatingmeans and one of the rst switch means. for activating. thel motor and coupling means. simultaneouslyto` rotate the rotary shafty and the rotatable; support, the control switch means being adapted to be positioned remotelyY from the rotaryshaft, each first switchmeansfunctioning upon engagement of the switch-actuating means: to deactivate. the motor and coupling means, whereby to stop.` therotation of the. rotary shaft after the latter has rotated through the angle selectedyby the corresponding.r control switch means,. and.

means independent of the motor forv returning.` z

the; rotatable support to its rest position after rotation.

35. A device for controlling the angular displacement of a. rotary shaft powered by an electrically actuated motor, said device comprising, -f

in. combination with an electrical' supply for ac'- tuating the motor; a control. shaft adapted to becoupled'tothe rotary shaft for rotation therewith, a pair of supports, one of the supports being; mounted for rotationand having a normal. rest position, electrically actuated. coupling. means releasably interconnecting'. the rotatable support and the controll shaft; circuit breaker means detachably connecting the. motor to the electrical supp1y;,e1ectrically actuated selector means in the yy,

circuit of the breaker andv coupling actuating means, first switch means mounted upon onefor the supports; and arranged in the circuit of the selector'- actuating; means, switchy actuating means mounted,` upon the othersupportin angular displacementwith therstswitch'means whenf the rotatable support is in` rest position, control switch means in the circuit of. the: selector-acituating` means for activating theimotor and; coupling means,` simultaneously.` to rotate the` rotary shaft and the rotatableI support,A the rst switch means functioning upon engagement. ofY the switch-actuating4 means to open the circuit of.l the-selector-actuating means and to deactivate.

themotorand coupling` means, whereby to stop the rotation of the; rotary shaft after the. latter has; rotated through the angle selectedf by the. control switch means, and meansy for returning the rotatable support to its. rest. positionafter rotation.

4;,A device for controlling the angular dis-f placement .ofi a rotary shaft powered by an electricallyv actuated: motor,V said device comprising in combination withl an electrical. supply for. ac.- tuating the motor; acont-rol shaft adapted torbe-v coupled to the rotary shaft for rotation therewith, a pair of` supports, onel of the-supports being mounted forv rotation and having a. normalA rest. position,.electrically actuatedvcoupling means re.- leasably interconnecting the rotatable support. and the, control shaft,V circuit breakery means detacha-bly connecting the. motor to i the.. electrical supply., a plurality of electricallyactuatedlselector means in the circuit of the breaker and.- cou.-

pling actuating means, a plurality of first switch c i6` rotatable support is in rest position, control switch means in the circuitl of each selector-actuating means for activating the motor and coupling means simultaneously to rotate the rotary shaft and the rotatable support, each first switch means functioning upon engagement of the switch-actuating means to open the circuitv of' the corresponding selector-actuating means and to4 deactivate the motor and coupling means,

whereby to stop the rotation of the rotary' shaiY-ty after the latter has rotated through the'angle selected bythe control switch means, and means for returning the rotatable support to its rest position after' rotation.

5. A device for controlling. the angular displacement of a rotary shaft powered by an electrically actuated reversible motor, said. device comprising, in combination with an electrical supply for actuating the motor; a control shaft.

adapted to be coupled to the rotary shaft for rotation therewith, a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasablyV interconnecting the rotatable support and the control shaft, circuit` breakerA means detachably connecting the motor tothe electrical supply for forward and reverser rotation, electricallyA actuated selector means in the circuit. of. the forwardbreaker and' coupling actuating means, first switch means mounted upon one of the supports and arranged. in the circuit. of the selector-actuating means, switchactuating means mounted upon the other support in angular displacement with the switch. means when the rotatable support is in rest position, control switch means in the circuit of. the. selector-actuating means for activating the motor and coupling means simultaneously'to rotate the rotary shaft. and the rotatablelsupport.

l the first switch meansfunctioning upon engage-` ment of the switch-actuating means to open the circuit of the selector-actuating means and to deactivate the'motor and coupling means, whereby to stop the rotation of the rotary shaft after 3 the latter has rotated` through the angleselected'i by the controlv switch'means, and means for returning the rotatable support to its rest position after` rotation.

6. A device for controllingY the angular displacement of a rotary'shaft powered by an electricallyy actuated reversible motor, said device comprising, in combination with an electrical' supplyfor actuating the motor; a control shaft. adapted to be coupled to the rotary shaft for roA tation therewith, a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasably interconnecting the rotatable support and the control shaft, circuit breaker means detachably connecting the motor to the electrical supply for forward and reverse rotation, a plurality of electrically actuated selector means in the circuit of the forward breaker andv coupling actuatingmeans, a plurality of rstswitch means mounted upon one of the supports and each arranged in the circuit of" one of the selector-actuating means, switch-actuating means mountedupon the other support,v ccntrolswitch means inthe circuit of .each select.- or-actuating meansfor activating the motor and coupling means. simultaneously to rotate the rotary. shaft. and the rotatable support, each firstV- switch, means functioning; upon. engagement of l thefsw-itch-actuating means-tol open-the. circuit,

of the selector-actuating means and to deactivate the motor and coupling means, whereby to stop the rotation of the rotary shaft after the latter has rotated through the angle selected by the corresponding control switch means, and means for returning the rotatable support to its rest position after rotation.

7. A sawmill setworks comprising, in combination with a saw, a carriage having knees mounted slidably thereon and driven by a set shaft powered by an electrically actuated motor, and an electrical supply for actuating the motor; a control shaft adapted to be coupled to the set shaft for simultaneous rotation therewith, a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasably interconnecting the rotatable support and the control shaft, first switch means mounted upon one of the supports and arranged in the circuit of the motor and coupling actuating means, switch-actuating means mounted upon the other support, the angular displacement between the switch-actuating means and the switch means when the rotatable support is in rest position being proportionate to the linear movement of the knees, control switch means in the circuit of the motor and coupling actuating means for activating the motor and coupling means simultaneously to rotate the set shaft and the rotatable support, the rst switch means functioning upon engagement of the switch-actuating means to deactivate the motor and coupling means, whereby to stop the rotation of the set shaft after the latter has rotated through the angle selected by the control switch means, and means independent of the motor for returning the rotatable support to its rest position after rotation.

S. A sawmill setworks comprising, in combination with a set shaft powered by an electrically actuated motor, and an electrical supply for actuating the motor; a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasably interconnecting the rotatable support and the set shaft, a plurality of rst switch means mounted upon one of the supports and arranged in the circuit of the motor and coupling actuating means, switch-actuating means mounted upon the other support in angular displacement with each switch means when the rotatable support is in rest position, a plurality of control switch means each arranged in the circuit of the motor and coupling actuating means and one of the rst switch means for activating the motor and coupling means simultaneously to rotate the set shaft and the rotatable support, the control switch means being adapted to be positioned remotely from the set shaft, each first switch means functioning upon engagement of the switch-actuating means to deactivate the motor and coupling means, whereby to stop the rotation of the set shaft after the rlatter has rotated through the angle selected by the control switch means, and means independent of the motor for returning the rotatable support to its rest position after rotation.

9. A sawmill setworks comprising, in combination with a saw, a carriage having knees mounted slidably thereon and driven by a set shaft powered by an electrically actuated motor, and an electrical supply for actuating the motor; a control shaft adapted to be coupled to the set shaft for rotation therewith, a pair of supports,

one of the supports being mounted for rotation and having a normal rest position, electrically actuated 'coupling means releasably interconnecting the rotatable support and the control shaft, circuit breaker means detachably connecting the motor to the electrical supply, a plurality of electrically actuated selector means in the circuit of the breaker and coupling actuating means, a plurality of first switch means mounted. upon one of the supports and each arranged in the circuit of one of the selector-actuating means, switchactuating means mounted upon the other support, the angular displacement between the switch-actuating means and each first switch means when the rotatable support is in rest position being proportionate to the linear movement of the knees, control switch means in the circuit of each selector-actuating means for activating the motor and coupling means simultaneously to rotate the set shaft and the rotatable support, each first switch means functioning upon engagement of the switch-actuating means to open the circuit of the selector-actuating means and to deactivate the motor and coupling means, whereby to stop the rotation of the set shaft after the latter has rotated through the angle selected by the control switch means, and means for returning the rotatable support to its rest position after rotation.

10. A sawmill setworks comprising, in combination with a set shaft powered by an electrically actuated reversible motor, and an electrical supply for actuating the motor; a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releasably interconnecting the rotatable support and the set shaft, circuit breaker means detachably connecting the motor to the electrical supply for forward and reverse rotation,V a plurality of electrically actuated selector means in the circuit of the forward breaker and coupling means, a plurality of first switch means mounted upon one of the supports and each arranged in the circuit of one of the selector-actuating means, switch-actuating means mounted upon the other support, control switch means in the circuit of each selector-actuating means for activating the motor and coupling means simultaneously to rotate the set shaft and the rotatable support, `each first switch means functioning upon engagement of the switch-actuating means to open the circuitof. the selector-actuating means and Ato deactivate the motor and coupling means, whereby to stop the rotation of the set shaft after the latter has rotatedA through the angle selected by the control switch means, and means for returning the rotatable support to its rest position after rotation.

11. A device for controlling from a remote Aposition the angular displacement of a rotary shaft powered by an electrically actuated motor, said device comprising, in combination with an electrical supply for actuating the motor, a control shaft positioned remotely from the rotary shaft, a pair of adjacent supports, one of the supports being mounted for rotation, coupling means releasably interconnecting the rotatable support and the control shaft, first switch means mounted upon one of the supports and arranged in the circuit of the motor-actuating means, -switch-actuatingmeans mounted upon the other support, the switch and switch-actuating means being disposed for mutual contact upon a predetermined rotation of the rotatable support,

19. operating means. connected. to. the coupling means for actuating the latter. whereby, respectively, to interconnect the rotatable support and control shaft so that the displaced first switch and switch-actuating means will be brought into mutual Contact upon actuation of the motor, and to disconnect the rotatable support and control shaft 'when the motor is stopped so that the rst switch and switch-actuating means may be displacedY in proportion to the desired angular displacement of the rotary shaft control switch means in the circuit of the motoractuating means. for activating the latter, the rst switch means functioning, upon engagement of the. switch-actuating means to deactivate the motor, whereby to. stop the rotation ofthe rotary shaft after the latter has rotated through the angle selected'by the initially displaced switch and switch-actuating means, and' electrical servo-mechanism coupling means interconnecting the remotely positioned control shaft and rotary shaft.

12. A device for controlling the angular displacement of a rotary shaft powered' by' an electrically actuated motor, said.` device comprising, in combination with an electrical supply for actu ating the motor; a pair of supports, one of the supports being mounted for rotation and having a normal rest position, electrically actuated coupling means releas'ably li'ntercc'nnecting the rotatable support and the rotary shaft, first switch means. mounted upon one of the' supports and arranged in the circuit of the motor and coupling actuating means, switch-actuating means mounted upon the. other supportin angular displacement with the .switchrneans 'when' the rotatable support is in rest position, the switch and switch-actuating means being disposed for mutual contact upon a predetermined rotation ofthe rotatable support, -controlswitcnmeans in the circuit of the motor-actuating means and coupling-actuating..means.for activating the motor and couplingA means simultaneously Yto ro'- tatethe rotary shaft and the rotatable support, the rst switch means fnctioningrupon engagement of the switch-actuating means to de activate the motor and coupling. meanswhereby tostop the rotation ofthe rotary shaftafter'the latter has rotated through the angle selecte'dby the control switch means, and means independent of the motor. for returning. the rotatable support to its rest position after rotation.

13. The device of claim 12 wherein. atleast one of. the. means (switch and switch-actuator) is mounted adjustably upon. itsrespective support for adjusting the angular .displacement there between.

14. The device of claim l2 including ai dial mounted for rotation with therotary shaft, the dial being graduatedto indicate theangular'displacement of saidrotary shaft.

15. The device of' claim 12 including safety switch means in the circuitrof the control switch means land mounted for actuation by the rotatable support in such manner that said safety switch closes the circuit of the control switch means whenthe rotatable support is in rest position and said safety switch opensthe circuit of the control switch means .when the rotatable support is moved out of its restposition.

, 16. The device of' claim 12 wherein the control switch means for operating the deviceis positioned remotely from the rotaryv shaft.

17. The device of claimV 3" including' safety switch means in the circuit ofthe control switch meansand mounted for actuation by therotatable support. in such manner that said safety switch closes the circuito! the control switch means when the rotatable support is in rest position and said safety switch opens the circuit of the control switch means when the -rotatable support is moved out of its rest position.

18. The setworks of claim 7 including a dial mounted' for rotation with the set shaft, and a nxed index mounted for registry with the dial, the dial being graduated to indicate with reference to the index the `distance between the knees and the plane ofthe saw.

19. The setworks of claim '7 including safety switch means in the circuit of. the control yswitch means and mounted for actuating by the rotatable support in such manner that said safety switch closes the circuit of the control switch means when the rotatable support is in rest position and said `safety switch opens the circuit of the control switch means when the rotatable support is moved out of its rest position.

20; The device of claim 7 wherein the control shaft, supports, electrically actuated coupling means `and switch means are positioned remotely from thesawmill carriageand the control shaft and set shaft are interconnected for cooperative rotation by electrical servo-mechanism coupling means.

2l. A sawmill setworks comprising, in combination with a set shaft powered by an electrically actuated motor, and an electrical supply for actuating the motor; a pair of supports, one of the supports being mounted for rotation and having a normal rest posit-ion, electrically actuated coupling-means releasablyinterconnecting the `rotatable support and theset shaft, first switch means mounted uponA one ofthe supports and arranged in the circuit of the motor and coupling actuating means, switch actuating means mounted upon the other support, the angular displacement between the switch-actuating means and the first switch means when the rotatable support is in rest position being proportionate to the angular displacement through which the set shaft is to be rotated, control switch means in the circuit of the motor and coupling actuating means for activating the motor and coupling means simultaneously to rotate the set shaft and the rotatable support, the first switch means functioning upon engagement of the switch-actuating means to deactivate the motor and coupling means, whereby to stop the rotation. of the set shaft after the latter has rotated through the angle selected by the control switch means, and means independent of the motor for returning the rotatable support toits rest position after rotation.

22. The setworks'of claimv2l wherein the control switch means for operating the setworks is positioned remotely fromthe' sawmill carriage.

23. A device for controlling the angular displacement of the set shaft'of a sawmill carriage assembly from a position remote from said carriage, wherein said set shaft is powered lby an electrically actuated motor; said device comprising a control shaft positioned remotely from the said carriage, a pair of yadjacent supports, one of the supports being mounted for rotation, coupling means vreleasably interconnecting the rotatable supportand the control shaftnrst switch means mounted upon one' of the supports and arranged in the-.circuit off the motor-'actuating means, switch-actuating means mounted upon the other support, theV nrstswitch and switch- `actuatlngi means being disposed' for. mutual con- 21 tact upon a predetermined rotation of the rotatable support, operating means connected to the coupling means for actuating the latter whereby, respectively, to interconnect the rotatable support and control shaft so that the displaced rst switch and switch-actuating means will be brought into mutual contact upon actuation of the motor, and to disconnect the rotatable support and control shaft when the motor is stopped so that the rst switch and switch-actuating means may be displaced in proportion to the desired angular displacement of the set shaft control switch means in the circuit of the motoractuating means for activating the latter, the

rst switch means functioning upon engagement l5 of the switch-actuating means to deactivate the motor, whereby to stop the rotation of the set shaft after the latter has rotated through the angle selected by the initially displaced first switch and switch-actuating means, and electrical servo-mechanism coupling means interconnecting the remotely positioned control shaft and set shaft.

THEODORE H. BALCH.

RAY F. VAN DE MARK.

References Cited in the le of this patent UNITED STATES PATENTS Number 22 Number Name Date 1,539,168 Dresser May 26, 1925 1,633,102 Jackson June 21, 1927 1,725,861 Grueter Aug. 27, 1929 1,836,496 Percy Dec. 15, 1931 2,175,822 Best Oct. 10, 1939 2,297,152 Jacke Sept. 29, 1942 2,342,967 Peters Feb. 29, 1944 2,362,690 Fichter et al. Nov. 14, 1944 2,440,849 Defandorf et al May 4, 1948 2,500,150 Bullard et al. Mar. 14, 1950 2,505,262 Torcheux Apr. 25, 1950 2,574,393 Hult Nov. 6, 1951 FOREIGN PATENTS Number Country Date 31,084 France Aug. 17, 1926 (1st `addition to 544,471)

614,020 Germany May 31, 1935 928,393 France June 2, 1947 OTHER REFERENCES Servomechanism Fundamentals by Lauer, Lesnick & Matson, McGraw-Hill Book Co., New

36 t0 38, 194 and 195).