US2970617A

US2970617A - Sawmill carriage preset system

Info

Publication number: US2970617A
Application number: US736306A
Authority: US
Inventors: Milton H Mater
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-05-19
Filing date: 1958-05-19
Publication date: 1961-02-07
Anticipated expiration: 1978-02-07

Description

Feb. 7, 1961 Filed May 19, 1958 M. H. MATER SAWMILL CARRIAGE PRESET SYSTEM 4 Sheets-Sheet 1 FlG.l

INVENTOR. MILTON H. MATER BY BUCKHORN, CHEATHAM &BLORE ATTORNEKS- Feb. 7, 1961 Filed May 19, 1958 M. H. MATER SAWMILL CARRIAGE PRESET SYSTEM 4 Sheets-Sheet 2 BUCKHOR INVENTOR. MILTON H. MATE R BY N, CH EATHAM 8 BLORE A TTORNEYS Feb. 7, 1961 I M. H. MATER 2,970,617

SAWMILL CARRIAGE PRESET SYSTEM Filed May 19, 1958 4 Sheets-Sheet 3 INVENTOR. 6/ 65 MILTON H. MATER sa b 64 BY BUCKHORN,CHEATHAM & BLORE ArroR/yEm Feb. 7, 1961 M. H. MATER SAWMILL CARRIAGE PRESET SYSTEM 4 Sheets-Sheet 4 Filed May 19, 1958 m E mm m Qw\ xv g. w NQ \9 M G U Q N m kw m, m m w m H b H i E3 1H u. \g m O BMW A& Q 09 02 0mm con Qom \m3 B o a vim i Z 5 i QM i To Nm NN .JJIL/ @w 5 9% Q9 wt 4 O 3 H L 15 J u i i FIIJII g N ww %& 2 0 s H I w l 6 m Ah n (r i i i v? M 5 we 9 ATTORNEYS United States Patent SAWMILL CARRIAGE PRESET SYSTEM Milton H. Mater, 520 S. 1st St, Corvallis, Oreg.

Filed May 19, 1958, Ser. No. 736,306

9 Claims. (Cl. 143-120) My present invention comprises an improvement in sawmill carriages of the type comprising a plurality of laterally movable knees for shifting a log or other member to be sawed relative to a saw. The invention comprises means for increasing the accuracy of a sawmill carriage setworks which is used to position the log, or remaining portion of the log, with relation to the saw.

The invention is herein specifically illustrated as comprising a fluid motor (compressed air) which actuates the knees each time a setting is made and which comes to a complete stop when the setting is completed. It is to be appreciated that the illustration is exemplary, and the motor involved may be a fluid motor (hydraulic) or an electric motor. In any case the motor is so designed as to operate normally at a maximum speed so as to accomplish the setting as quickly as possible, and there is operatively associated therewith a speed controller for reducing the speed of the motor from the maximum to a minimum during the last few increments of travel of the knees. For example, when it is desired to cut a one inch board with this type of setworks, the motor is started to move the log toward the plane of the saw at a maximum speed. Shortly before the one inch movement is completed the motor speed is progressively decreased to a minimum, so that the inertia of the log and the knees will not carry the log past the one inch setting when the knees are bro'ught to a halt. It will readily be appreciated that the high speed of the motor, which progresses the log and knees forward at a rate of some fifteen to twenty-five feet per minute, results in a very large momentum (momentum equals mass times the velocity). If the log being moved were always of the same weight, the momentum could be taken care of by allowing an overtravel after the motor was shut off, up to a certain extent but not to a fine degree of accuracy for the reason that the wear on mechanical parts occasioned by attempting to bring such a traveling mass to a halt would be great. Also, such a device would be impractical for the reason that each pass of the carriage results in reducing the mass of the log. Accordingly, aprimary object of the present invention is to provide means wherebythe final travel of the knees and the log during each setting of the carriage is accomplished at a progressively reducing speed, the speed being reduced to a range of about three to five feet per minute immediately before bringing the movement to a halt. Since the reduction in speed reduces the momentum in proportion to the speed, the momentum at the final portion of the movement is low, sufiiciently low as to be negligible. As a result, the setting of the knees can be accomplished with a high degree of accuracy no matter what size or weight of log is being cut. 1

A further object of the present invention is to provide means for simplifying a setworks control circuit. In this respect the present invention comprises an improvement upon the setworks control means illustrated, described and claimed in the patent to Smith et al. 2,807,- 293 issued September 24, 1957.

2,970,617 Patented Feb. 7, 1961 Other objects and advantages of the present invention will be more readily apparent from inspection of the following specification, taken in connection with the accompanying drawings, wherein like numerals refer to like parts throughout.

In the drawings,

Fig. 1 is a schematic plan view of a sawmill, including a carriage and setworks of the present invention;

Fig. 2 is a schematic diagram of the motor, speed controller, and associated mechanism;

Fig. 3 is a vertical central section, somewhat schematic, through a preset device mounted upon the carriage, showing a control drum and a cam drum in one relative positIon thereof; taken substantially along line 3-3 of Fig. 5, parts of the construction being broken away for clarity;

Fig. 4 is a side elevation of the preset device with the casing broken away to show the control drum and cam drum;

Fig. 5' is a vertical section taken substantially along the line 5-5 of Fig. 3, parts of the construction being broken away for clarity;

Fig. 6 is a vertical section, somewhat schematic, illustrating a magnetic clutch and low speed controller;

Fig. 7 is a schematic view illustrating the arrangement of the magnetic clutch;

Fig. 8 is a schematic, wiring diagram comprising a part of the invention; and

Fig. 9 is a schematic, wiring diagram illustrating a modification of the invention.

Fig. 1 schematically illustrates a typical sawmill arrangement, including a head saw 10 driven by a motor 11. A wheel-mounted carriage 12 is reciprocated past the head saw by suitable means exemplified by the cable 13, the wheels of the carriage being guded by tracks 14. At each reciprocation of the carriage in one direction the saw removes a section of the log 15 which is mounted on the carriage. The log rests upon movable knees 16 and is held in position thereon by dogs 17. The knees are laterally movable so as to position the log with respect to the head saw, the depth of cut being controlled by the extent of movement of the knees.

The knees are driven by suitable means exemplified by the set shaft 18 which is operatively connected by means (not shown) to each of the knees so that they move in unison, either forward or reverse as controlled by a sawyer positioned at the sawyers seat 20. The sawyer is within reach of a preset panel 21 in which are mounted a plurality of preset or selector push buttons 22 of the type including means to hold the selected button in depressed or contact making position until another selector button is depressed. Such buttons control the forward movement of'the knees through a preselected, predetermined distance when a preset actuator button is subse quently depressed. The sawyer is also within reach of a motor control panel 23 having push buttons thereon, including a fast forward button 24, a reverse button 25, a slow forward button 26 and the preset actuator button 27. The forward and

reverse buttons

24, 2S and 26 provide manual control of the knees independent of the preset selector buttons 22 and the actuator button 27. When a preset selector button 22 has been depressed and then the preset actuator button 27 depressed the knees are moved forwardly first at a fast forward speed and then at a slower forward speed and finally stopped after they have moved through the predetermined distance selected by the depressed selector button 22. The preset actuator button 27 is magnetically held in depressed position until the completion of such movement and then automatically released.

Succeeding logs to be cut are held in readiness on a transfer deck 30 with which are associated blocking lug means 31 and transfer means 32 suitably controlled so that logs may be rolled onto the carriage when needed. A control circuit is embodied in the invention, one form of the circuit being schematically set forth in Fig. 8 and explained later, there being connections (not shown in Fig. 1) between the sawyer controls described above and the devices mounted on the carriage.

The set shaft 18 is rotated by a variable speed motor 35 suitably mounted on the carriage and connected to the set shaft through a chain and sprocket drive 36. An electrically actuated brake 37 is associated with the motor to arrest the motor and hoid it stationary at the completion of each setting movement. The motor may be of the fluid (air or hydraulic) type, or electric, and normally operates at a high speed. The motor may operate at a slow speed, either under manual control of the sawyer or under automatic control by the preset system. Associated with the motor is a reversing valve 38 (see also Fig. 2) comprising a body into which there is a central inlet or supply conduit 39. Laterally spaced conduits 4d lead from the reversing valve to the motor inlet to determine the direction of rotation of the motor. Compressed air to run the motor is supplied by a pump 41 discharging into an accumulator tank 42 which supplies air to the conduit 39. When a valve stem 4-4 of the valve 38 is centrally positioned as illustrated in Fig. 2, the lands d thereon block the flow of air to the motor. The valve stem 44 may be moved in either direction upon energization of a solenoid coil 46 or a solenoid coil 47 under control of the forward and reverse buttons 24- and 25. Energization of one of the solenoids causes an abutment 48 fixed to the valve stem to compress one or the other of a pair of centering springs 50 which automatically return the valve to its neutral, airblocking position upon de-energization of the selected solenoid.

When the valve stem is moved in either direction to supply air in the appropriate direction to the motor, a branch passage of an outlet conduit 51 is also uncovered, which outlet conduit leads to a speed control valve 52. The speed control valve comprises an elongated port 53 which is normally open but which is positioned so as to be progressively closed by the land 54 on a valve stem 56. The valve stem 56 may be moved progressively by a magnetic clutch 57 having an arm 58 connected to the valve stem, such movement being accomplished against a spring 59 (Fig. 6). When the magnetic clutch is energized the land 54 progressively covers the port 53, progressively restricting the exhaust of air from the motor, and thus progressively reducing the speed of the motor whereby the velocity of the knees is progressively reduced from a maximum to a minimum speed.

A form of magnetic clutch for the speed control valve is illustrated in Figs. 6 and 7, somewhat schematically but in sufficient detail to understand the operation thereof. A control shaft 61 is mounted on the carriage and a chain and sprocket drive means 62 connects the control shaft to the set shaft 18 so that the control shaft is revolved at a speed in direct ratio to the speed of movement of the knees and to an arcuate extent in direct ratio to the linear movement of the knees. The magnetic clutch 57, schematically illustrated in Figs. 1 and 2, is herein illustrated as comprising a driving clutch element consisting of a disc 63 keyed to the control shaft 61 so as to move whenever the knees move. A driven clutch element 64 comprises a disc rotatably mounted on shaft 61 alongside of the disc 63 and is pressed by a spring 69 toward the disc 63 so as to be normally frictionally driven thereby. Another disc 65 is also rotatably mounted on the shaft 61 and has a clutch actuatprovided with a head 67 which compresses the spring 59 against a shoulder '68 on the body of the valve, the spring partially encircling the valve body. When the coil 65 is not energized the

discs

63 and 64 rotate in unison. This action occurs only when the knees 16 are moving forward, which rotates the control shaft 61 clockwise as seen in Fig. 6, thereby drawing the valve stem toward the right as seen in both Figs. 2 and 6, and compressing the spring 59. This progressively closes the vent 53, progressively slowing down the motor until the port is nearly closed, at which point the back pressure on the motor is sufficient to cause the motor to be driven at a low, minimum speed. When the knees reach the desired position, means, to be described later, energizes the actuating coil of the magnetic clutch, permitting the spring 59 to return the speed control valve to its normal position. Simultaneously therewith the valve 38 is returned to its neutral or inoperative position, blocking any further flow of air to the motor, and brake 37 is set to hold the motor stationary and the knees at their set positions. 7

Thecontrol shaft 61 projects from a controlmeans housing 70 in which are control means detailed in Figs. 3, 4 and 5. One end of the control shaft has a chain and sprocket drive 62 connected thereto, as illustrated in Fig. l, and the opposite end supports the magnetic clutch 57. The control shaft is rotatably supported in suitable bearings 71 within the housing 70. Mounted upon the control shaft are a pair of drums, a cam drum 72 and a control drum 73, a flange of which concentrically surrounds the cam drum. The cam drum 72 is fixed to the shaft by a key 74, a taper collar 75, and a set screw 76. The hub of the cam drum is provided with a concentric projection 78 which supports a ball bearing assembly 79, which in turn rotatably supports the control drum 73. A disc 81 is fixed to the control drum by screws 82. The disc is provided with a concentric extension 84 which extends away from the control drum in closely surrounding relation to the control shaft 61 and which supports a plurality of suitably insulated slip rings 85 keyed thereto. The rings 85 are partially surrounded by a brush housing 86 in which there are a plurality of brush mounting sockets 87, each of which contains an insulated brush mount88 enclosing a spring-urged brush 89 male ing contact with one of the rings 85. Individual wires of the control circuit are bunched into a cable, indicated at 90 in Fig. 4, leading from a multi-pin plug 91 fitted into a multijack socket 92 (Figure 3) suitably mounted in the housing.

The disc 81 mounts a plurality of resistors 95 arranged circumferentially on an insulated plate 96 fixed to the disc 81. As shown in Fig. 8 certain of the resistors 95 are connected in series by means of the taps 97 (Fig. 3) and are also connected to control circuits through the slip rings 85 by suitable conductors which are not shown on Figs. 3 to 5.

The control drum 73 is provided with a pair of circumferentially extending slots 100 which do not extend entirely around the drum so that there is sufiicient metal at circumferentially spaced positions on the drum to hold all portions of the drum together. A plurality of pairs of control switches 181 and 102 (Fig. 5) are adjustably mounted in the slots 100 so as to project inwardly from

adjustable holders

103 and 104, respectively, as shown in Fig. 5. Each pair of switches is arranged diagonally with respect to the axis of the control drum so that the switch 101 is slightly in advance of the switch 102 in each pair. Each pair of switches corresponds to one of the preset selector buttons 22 and such switches are connected by wires (not shown in Figs. 3 to 5) into control circuits which cause rapid forward movement of the knees to be reduced to slow forward movement when a switch 101, corresponding to a depressed preset button, is closed and to stop the knees when the other switch 162 corresponding to such depressed push button is closed.

Each

switch

101 or 102 is mounted in a thimble 105 which may he slid circumferentially to a desired position in the slot and which is provided with an internal flange engaging the interior surface of the drum. An eccentric projection 106 on the thimble supports the switch so that by rotating the thimble and, if necessary remounting the switch on the projection, the position of the switch axially with respect to the cam drum 72 may be placed .in either of three possible arrangements so as to be contacted by any one of the different movable cams 107 on the cam drum 72. Thus the cam drum 72 is provided with six cams 107 arranged in groups of three. Upon relative rotation of the cam drum with respect to the control drum, the cams successively engage and operate the

switches

101 and 102. By displacing the cams 107 in each group of three a short distance circumferentially of the drum with respect to each other, a cam 107 can be selected for a given

switch

101 or 102 to actuate such switch at any desired relative angular position of the

drums

72 and 73 even though there are certain angular positions on the control drum 72 in which a switch cannot be positioned because of the necessary support elements extending across the slots. Each cam is of sufficient length to'maintain switch 101 of each pair closed until switch 102 is also engaged and closed. The circumferential spacing between pairs of switches is preferably greater than the length of a cam 107, so that only one pair of switches may be engaged no matter how many pairs are utilized, although this condition is not a requirement in the circuit of Fig. 8. The switches are held in their adjusted positions by washers 109 through which pass bolts 110 threaded into the thimbles 105.

Mounted alongside of the control dinm there are brake means for holding the control drums stationary upon initiation of a forward movement of the knees under control of the preset circuit. The brake means comprises a pair of brake shoes 115 mounted respectively on opposite sides of the control drum flange upon a pair of

levers

116 and 117 pivotally connected one above the other to a standard 118. The lower control lever 117 extends beyond the brake shoe associated with it and supports a solenoid 120, the weight of which causes the lower brake shoe to normally remain in released position. The plunger 121 of the solenoid projects upwardly and is pivotally connected to a bracket 122 which extends above the corresponding end of the upper lever 116. A bolt 123 projects upwardly from lever 116 and is provided with a head above the bracket 122 to hold the bracket in position. A spring 125 connected between arm 116 and a bracket 126 resiliently urges the arm upwardly to move the upper brake shoe 115 to released position. A spring 127 surrounds the bolt between the arm 116 and the bracket 122 so that the brake pressure is resiliently applied when the plunger 121 is drawn into the solenoid upon energization of the solenoid 120. The brake shoes are applied to the drum immediately upon operation of the preset actuator button 27 so as to hold the control drum 73 stationary while the cam drum 72 rotates.

A pin 130 (Figs. 3 and projecting forwardly from the hub of the control drum 73 mounts one end of a spring 131, the other end of which is hooked into the hub of the cam drum 72 in such manner that as the cam drum rotates the spring is tightened, thus biasing the control drum to follow the cam drum when it is released. When a preset selector button 22 has been depressed and the actuator button 27 is depressed control valve 38 for the motor 35 is actuated to cause the motor to drive shaft 18 to move the knees forwardly. At the same time the magnetic clutch 57 is energized to disengage such clutch so that the knees are driven at a maximum speed. Shaft 61 and cam drum 72 are also rotated in a counter clockwise direction in Fig. 5. The cams 107 successively close the pairs of

switches

101 and 102. As one of the cams 107 engages the switch 101 corresponding to the depressed preset selector button 22, a circuit is closed to deenergize the magnetic clutch 57 causing such clutch to be engaged. This progressively closes the speed control valve 52 to cause movement of the knees progressively to decrease. Progressively slower movement continues until a cam 107 engages the switch 102 also corresponding to the depressed preset selector button 22. This causes the valve 38 to return to neutral, the speed control valve 52 to return to its open position, application of the setwork brake 37, and release of the brake shoes to allow the control drum 73 to be returned to its zero position relative to the cam drum 72 by the spring 131.

The cam drum 72 is provided with a radially projecting abutment which is immediately behind the cam means 107 with respect to the direction of rotation. When the control device is at a zero setting, as illustrated in Fig. 5, the abutment 135 is engaged by the head 136 of a buffer plunger 137 mounted in an offset portion 138 of the control drum 73, the buffer including a spring 139 surrounding the stem of the plunger 137 and a rubber bushing 140 also surrounding the stern and arranged to take up the final shock of halting the rotation of the control drum to catch up to the cam drum. The spring 131 constantly urges the buffer head 136 against the abutment 135 and holds the two drums in a zero setting whenever the brake shoes 115 are released at any position of the knees. Thus forward movement of the knees under control of the preset selector buttons is always from a zero setting to the preselected forward setting.

When the reverse button 25 is depressed the brake 37 is released, the valve 38 is placed in reverse position and the motor started in reverse. The magnetic clutch 57 is energized to release such clutch but the solenoid 120 for the control drum brake shoes 115 is not energized so that the control drum 73 and the cam drum 72 move in reverse in unison, held together by the spring 131. Such reverse movement is at high speed. The sawyer, after moving the knees in reverse, then moves the knees forward, by depressing either of the

forward buttons

24 or 26, to an initial setting from which the preset selector buttons 22 and actuator button 27 can be employed to move the knees forwardly predetermined preset distances.

The shaft 61 projects through the magnetic clutch and is connected by suitable means (not shown) to a dial and pointer indicator (Fig. 1) mounted upon the carriage and facing toward the sawyer. The indicator indicates the total set back of the knees from the saw line, giving the sawyer immediate knowledge of the total amount of log remaining to be sawed at any given moment. However, since the preset control device is automatically returned to a zero setting at the completion of each setting movement, the sawyer need not mentally calculate what setting of the dial is required for the width which he selects for the next cut. There is, in fact, no calculation necessary for a given thickness of the next out since the control buttons 22 will each be marked to indicate the thickness of the board or slice which will be made on the next passage of the carriage. All the sawyer has to do is to select the proper button.

The operation of the device will be explained in connection with the description of a suitable control circuit for accomplishing the operation described above. Such control circuit is shown in Fig. 8. In this figure, the preset selector buttons 22 are each shown as a pair of normally open contacts. Such buttons, in conjunction with corresponding pairs of the cam operated

switches

101 and 102, cause operation of

opposed relays

147, 148, 149 and 150 which have opposed actuating coils. The upper bank 151 of push buttons 22 and upper bank 152 of

switches

101 and 102 cause operation of relays 147 and 14-9 and the lower banks 153 of push buttons 22 and lower bank 154 of

switches

101 and 102 cause operation of

relays

148 and 150. Each such relay has one pair of contacts which are normally open. The relay circuits are supplied with D.C. power from a bridge rectifier circuit 155 connected across the two conductors L and L of an A.C. single phase line. v

For purposes of explanation, assume that push button 22' in the upper bank 151 of preset selector buttons is depressed to close the two circuits therethrough, and that the preset actuator button 27 is then depressed to close the two circuits therethrough. Push button 22' is held in depressed position by any suitable or known mechanical interlock until another push button 22 is depressed. Push button 27 is magnetically held in depressed position by a hold solenoid coil Depression of actuator push button 27 after the selector push button has been depressed completes a circuit from one side of the rectifier circuit 155 through conductor 157, lower contacts of push button 27, conductor 158, contacts 159 of push button 22', resistors 161 and 161, actuating coil 162 of relay 147 and conductor 163 to the other side of the rectifier circuit 155. This energizes coil 162 to close normally open contacts 164 of relay 147. Closing contacts 164 completes a circuit from one side L of the A.C. line through conductor 165, contacts 164 and conductor 166, solenoid coil 46 and conductor 167 to the other side L of the A.C. line. This energizes solenoid coil 46 (see Fig. 2) to actuate valve 38 to cause the motor 35 to drive the carriage knees forwardly.

The actuating coil 168 (Fig. 8) of another relay 169 is connected in parallel with the solenoid coil 46 so, that relay 169 is also actuated upon closure ot contacts 164- of relay 1 57. This opens normally closed contacts 170 of relay 169 to open a normally closed circuit through the actuating coil 37' of the brake 37 (Pig. 2) for motor 35 to release such brake and enable the motor 35 to rotate. The normally closed circuit through such brake actuating coil 37' (Fig. 8) can be traced from L through conductor 165, conductor 171, the lower normally closed contacts of reverse push button 25, normally closed contacts 17th of relay 169, brake actuating coil 37' and conductor 167 to- L Actuation of relay 169 also closes normally open contacts 172 thereof to complete a circuit through holding solenoid coil 15s for the selector actuator push button 27. Such circuit can be traced from the rectifier circuit 155 through conductor 157, coil 15%, and contacts 172 to the other side of the rectifier circuit. This energizes coil 1% to hold the push button 27 in depressed position.

Depression of

push button

22 and 27 also closes a circuit through the actuating coil 173 of relay 149. This circuit can be traced from one side of the rectifier circuit 155 through conductor 157, lower contacts of push button 27, conductor 158, contacts 174 of push button 22,

resistors

175 and 17 6, coil 173 of relay 149 and conductor 163 to the other side of rectifier circuit 155. Energizing coil 173 of relay 149 closes normally open contacts 177 thereof to complete a circuit through the actuating coil 65' for the magnetic clutch. of Figs. 6 and 7. The circuit can be traced on Fig. 8 from L through conductor 1o5,-contacts 177 of relay 14%, conductor 178, coil 65' and conductor 167 to L This energizes the coil 65' to release the clutch 57 so that the valve 52 of Figs. 2 and 6 is not actuated to slow down the motor 35, thus allowing the motor to run at high speed.

Depression of preset actuator push button 27 also cornpletes a circuit through the solenoid 1261 which sets the brake shoes 115 of Figs. 3 and against the control drum 73. This circuit can be traced on Fig. 8 from L through conductor 155, conductor 171, the upper contacts of push button 27, brake solenoid 12d and conductor 167 to L This holds the control drum stationary so that the cam drum 72 is rotated relative thereto as the knees are driven forwardly by the motor 35.

De ression of preset actuator button 27 also closes circuits through the opposing coils 179 and 1863 of relays 147 and l tg, respectively, but such circuits initially contain'suhicient resistance that the energization of coils 162 and 173 of such relays respectively is suflicien'tly greaterthan the energization of coils 17$ and 180 to cause actuation of the relays as above described. Such circuit through coil 1755 of relay 147 can be traced from the rectifier circuit 155 through conductor 157, the lower contacts of push button 27, conductor 158, conductor 181, the upper row of series connected resistors associated with the upper bank 152 of cam operated switches 1411 and N2 in- Fig. 8, conductor 182, coil 179 and conductor 163 to the other side of the rectifier circuit. A similar circuit can be traced from conductor 181 through the lower row of series resistors in the upper bank of

switches

101 and 102 of Fig. 8, conductor 133, coil 180 of relay 14) and conductor 163.

Rotation of the cam drum 72 with the control drum held stationary by the brake shoes 115, causes the cams Hi7 progressively to close the switches M1 and 102 beginning at the left in the upper bank 152 of such switches and progressing toward the right and then beginning at the left in the lower bank 154 of such switches and progressing toward the right. lrogressive closing of such switches in the upper bank thereof progressively cuts out resistance in the two circuits just traced through the coils 179 and 181) of the

relays

147 and 149 respectively. This progressively increases the energization of such coils until they overcome the effect of the energization of coils 162 and 173 respectively of such relays to cause the relays to again open their contacts 164 and 174 respectively. The values of the various series resistors 95 and the series resistors associated with the push buttons 22 are such that a relay M7 or 149 is either in open position or closed position. In the particular example selected, the relay 149 holds the contacts 177 closed until switch lltlii corresponding to contacts 174- of push button 22 is closed. At this time relay 149 is actuated to open contacts 177 thereof. This deenergizes the actuating coil 65' of magnetic clutch 5'7 of Figs. 2, 6 and 7 to cause such clutch to be engaged and operate the valve 52 to slow down the motor 35. At a predetermined distance of movement of the knees thereafter, the switch M2 corresponding to the contacts 159 of push button 22' is closed. This sufficiently energizes coil 179 of relay 147 to overcome the efiect of the energization of coil 162 of such relay and cause opening of contacts 164.

Opening of contacts 164 of relay 147 breaks the circuit through ooil 4-6 of the valve 33 to stop motor 35. It also breaks the circuit through coil 168 of relay 1:19 to cause opening of contacts 172 and closing of contacts 17%). Closing contacts 174D completes the circuit through coil 37 of the motor brake to apply such brake and stop the motor. Opening contacts 172 breaks the circuit through hold solenoid coil 156 for the push button 27 thus allowing such push button to open its contacts. Opening the lower contacts of push button 27 opens all circuits through push buttons 22 and switches 101 and 1412. Opening the upper contacts of push button 27 deenergizes solenoid to release the brake shoes 115 from engagement with the control drum 73 allowing the spring 131 of Fig. 5 to return such drum to its zero position relative to the cam drum 72 and the circuit is in its original condition ready for another preset operation controlled by the push button 22' or any other preset selector button 22 depressed in the meantime.

The lower bank 153 of push buttons 22 of Fig. 8 is connected in the circuits with relays 148 and in exactly the same way as the upper bank 1.51 of push but tons 22 is connected in the circuits with relays 1 2-7 and 149. Similarly the lower bank 154- of switches 1411 and 102 are connected in the circuits with relays 143 and 15% in exactly the same manner as the upper bank 152 of such switches are connected in the circuits with

relays

147 and 149. The normally open contacts 184 and of relays 148 and respectively are in parallel with normally open contacts 164- and 177 respectively of

relays

147 and 149 respectively. This means that if no push button 22 in the upper bank of such push buttons in Fig. 8 is depressed but a push button 22 in the lower bank thereof is depressed, the cam drum upon depression of push button 27 will rotate while progressively closing all of the

switches

101 and 102 in the upper bank of such switches and then continue to rotate while closing

switches

101 and 102 in the lower bank until the

switches

101 and 102 in each lower bank corresponding to the depressed push button 22 are reached.

The fast forward push button 24 has normally open upper contacts connected in parallel with the normally open contacts 177 and 185 of relays 149 and 159 and also normally open lower contacts connected in parallel with normally open contacts 164 and 184 of

relays

147 and 148. Depressing the fast forward push button to close its contact therefore has the same effect as closing normally open contacts 164 and 177 of

relays

147 and 149 which, as described above, is the condition for fast forward speed of the knees.

The slow forward push button 26 has normally open contacts in parallel with the normally open lower contacts of fast forward push button 24 but has no other controls. Such contacts are in parallel with normally open contacts 164 and 184 of

relays

147 and 148. The effect of depressing slow forward push button 26 is therefore the same as closing normally open contacts 164 of relay 147 while leaving open contacts 177 and 185 of

relays

149 and 150. This is the condition of the circuit for slow forward speed of the knees as described above.

Depressing reverse push button 25 drives the motor in a reverse direction at the high speed. Such button has normally open upper contacts in parallel with normally open contacts 177 and 185 of

relays

149 and 150. Closing of such upper contacts therefore disables the slow speed control drive by energizing the actuating coil 65' of its magnetic clutch 57. The push button also has intermediate normally open contacts which, upon being closed, cause energization of the reverse coil 47 (see also Fig. 2) of the valve 38 for the motor 35 so that the motor is driven in a reverse direction. The circuit for energizing coil 47 may be traced on Fig. 8 from L through conductor 165, conductor 171, intermediate contacts of prsh button 25, reverse coil 47 and conductor 167 to L The push button 25 also has normally closed lower contacts in series with the actuating coil 37 for the motor brake 37 so that opening of such contacts releases the brake 37 to enable the motor to drive the knees through the shaft 18 of Fig. 1.

From the above description, it is apparent that the sawyer has complete manual control of the movement of the knees in a forward or reverse direction, such movement continuing as long as the

appropriate push button

24, 25 or 26 is depressed and stopping when the depressed button is released. The sawyer can also preset any board thickness desired within the limits of the device by depressing an appropriate button 22. Any time the preset actuator button 27 is thereafter depressed, the device will move the knees forward the distance corresponding to the depressed button 22 and the actuator button 27 remains depressed until such movement is completed and will then be released ready for another actuation of the preset mechanism. As many or as few banks of selector push buttons 22 and

control switches

101 and 102 as needed for a particular installation can be employed. The two banks of

switches

101 and 102 shown in Fig. 8 employ five of the slip rings 85 of Fig. 3 and another similar bank would use the remaining two slip rings. Additional slip rings could, of course, be provided for more banks of switches.

A modified circuit for the banks of

switches

181 and 102 on the control drum 73 is shown in Fig. 9. The circuit of such figure can be substituted for each of the

banks

152 and 154 of

switches

101 and 102 of Fig. 8.

The substitution for the upper bank 152 only of such switches will be described. Appropriate resistors 195 are shown as each being connected in series with a

single switch

101 or 102 between the conductor 181 and the

conductors

182 and 183. The values of the resistors 195 are chosen so that the amount of resistance in series with the coils 179 or of the

relays

147 and 149 respectively upon closure of corresponding switches in the circuits of Figs. 8 and 9 is the same in both circuits. The advantage of the circuit of Fig. 9 is that the value of any given resistor can be changed or adjusted without affecting the other portions of the circuits. It will be apparent that similar parallel arrangements of the resistors can also be employed for the series arrangements of resistors in the banks of 151 and 153 of preset selector push buttons 22, if desired.

Having illustrated and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that the same permits of modification in detail and arrangement. I claim as my invention all such modifications as come within the true spirit and scope of the appended claims.

1 claim:

1. A sawmill and setworks comprising a carriage, a plurality of laterally movable knees mounted on said carriage, a variable speed motor mounted on said carriage, driving means connecting said motor to said knees for actuation of the latter, a speed controller operatively associated with said motor and normally remaining at a maximum speed setting, a control shaft mounted on said carriage, driving means connecting said control shaft to said means for driving said knees whereby said control shaft is rotated at a speed corresponding to the speed of movement of said knees and to an extent corresponding to the extent of movement of said knees, a cam drum driven by said control shaft, a control drum rotatably mounted on said cam drum, first spring means biasing said control drum to follow said cam drum, brake means to hold said control drum stationary while said cam drum rotates and stores energy in said first spring means, a plurality of pairs of switches mounted circumferentially of said control drum, a control circuit including means to condition a selected pair of said switches to stop a movement of said knees, cam means on said cam drum successively engaging said pairs of switches during movement ofsaid cam drum relative to said control drum, said cam means being so arranged with respect to said switches as to engage one switch of each pair prior to the other, a clutch including a part driven by said control shaft and a normally disengaged, neutrallypositioned, second part, spring means normally maintaining said normally disengaged part of the clutch at a neutral position, said control circuit including means to engage said clutch when the first switch of the conditioned pair of switches is engaged by said cam means, means driven by said clutch when engaged to actuate said speed controller progressively to decrease the speed of said motor, said control circuit including means operative when the second switch of said conditioned pair is engaged by said cam means simultaneously to arrest said motor and said knees, to release said brake means whereby said control drum is advanced by said first spring means to a zero setting with respect to said cam drum, and to release said clutch whereby said second spring means returns said normally disengaged part of the clutch to its neutral position and said speed controller to its normal position. 2. The construction set forth in claim 1 wherein said motor comprises a fiuid motor and said speed controller comprises a valve progressively increasing the back pressure on said motor.

3. The construction set forth in claim 1 wherein said motor comprises an air motor and said speed controller comprises a valve progressively closing the air exhaust port of said motor.

4. The construction set forth in claim 1 wherein said control circuit comprises a first set of resistances each connected into the circuit between successive pairs of said switches, a set of manually actuated selector buttons, a second set of resistances each connected into the circuit between successive buttons of said set of buttons, a manually c'losable motor actuator switch, interlock means between said selector buttons to hold a depressed button in circuit closing position until another button is depressed, a holding circuit including said first and second 'sets of resistances to hold said actuator switch in circuit closing position when manually closed, and means in said holding circuit to release said actuator switch when said cam means engages the second switch of the conditioned pair of said pairs of switches.

5. A setworks for a sawmill comprising a carriage, a plurality of laterally movable knees mounted on said carriage, a variable speed motor mounted on said carriage and driving means connecting said motor to said knees for actuation of the latter, said setworks comprising a speed controller operatively associated with said motor and normally remaining at a maximum speed setting, a control shaft mounted on said carriage, driving means connecting said control shaft to said means for driving said knees whereby said control shaft is rotated at a speed corresponding to the speed of movement of said knees and to an extent corresponding to the extent of movement of said'knees, a cam drum driven by said control shaft, a control drum rotatably mounted with respect to said cam drum, first spring means biasing said control drum to follow said cam drum, brake means to hold said control drum stationary while said cam drum rotates and stores energy in said first spring means, a plurality of pairs of switches mounted circumferentially of said control drum, a control circuit including means to condition a selected pair of said switches to stop a movement of said knees, cam means on said cam drum successively engaging said pairs of switches during movement of said cam drum relative to said control drum, said cam means being so arranged with respect to said switches as to engage one switch of each pair prior to the other, said control circuit including means operable when the first switch of the conditioned pair of switches is engaged by said cam means to actuate said speed controller progressively to decrease the speed of said motor, said control circuit including means operative when the second switch of said conditioned pair is engaged by said cam means simultaneously to arrest said motor and said knees, to release said brake means whereby said control drum is advanced by said first spring means to a zero setting with respect to said cam drum, and to return said speed controller to its normal position.

6. A setworks for a sawmill comprising a carriage, a plurality of laterally movable knees mounted on said carriage, a variable speed motor mounted on said carriage and driving means connecting said motor to said knees 'for actuation of the latter, said setworks including a speed controller operativeiy associated 'with said motor and normally remaining at a maximum speed setting, a control shaft mounted on said carriage, driving means connecting said control shaft to said means for driving said knees whereby saidcontrol shaft is rotated at a speed corresponding to the speed of movement of said knees and to an extent corresponding to theextent of movement of said knees, a cam drum driven by said control shaft, a control drum mounted on said shaft, one of said drums being fixed to said shaft and the other being rotatable with respect thereto, first spring means biasing said drums to follow one another, brake means to hold said other drum stationary while said one drum rotates, a plurality of pairs of switches mounted circumferentially of said control drum, a control circuit including means to condition a selected pair of said switches to stop a movement of said knees, cam means on said cam drum successively engaging said pairs of switches during movement of said cam drum relative to said control drum, said cam .means being so arranged with respect to said 12 switches as to engage one switch of each pair prior to the other, a clutch including a part driven by said control shaft and a normally disengaged, neutrally positioned part, second spring means normally maintaining 'said normally disengaged part of the clutch at a neutral position, said control circuit including means to engage said clutch when the first switch of the conditioned pair of switches is engaged by said cam means, means driven by said clutch when engaged to actuate said speed controller progressively to decrease the speed of said motor, said control circuit including means operative when the second switch of said conditioned pair is engaged 'by said cam means simultaneously to arrest said motor and said knees, to release said brake means whereby said control drum is advanced by said first spring means to a zero setting with respect to said cam drum, and to release said clutch whereby said second spring means returns said normally disengaged part of the clutch to its neutral position and said speed controller to its normal position.

7. A setworks for controlling the movement of the knees on a sawmill carriage including a motor for moving said knees, a brake for said motor, said setworks comprising an electrical control circuit for said motor including a brake operating means comprising a relay having opposed operating coils including a first, brake neutralizing coil and a second, brake applying coil, said relay having a first position in which said brake is main tained in neutral position and a second position in which said brake is moved to motor braking position, a first plurality resistor means, a second resistor means, asource of electrical energy, switch means for starting said motor and selectively operable to connect said resistor means to said source with a predetermined value of resistance in series with one of said coils, said switch means also connecting said second coil to said source with said second resistance means in series with said second coil, said second resistance means having a total resistance greater than that of said first resistance means whereby said relay initially operates to brake neutralizing position, and means operatively connected to said knees for progressively decreasing the value of the resistance in series with said second coil as said knees move in response to said motor so that the voltage applied to said second coil will increase upon movement of said knees and at a predetermined point said second coil will overcome said first coil to move said relay to brake applying position and thus effect actuation of said brake to stop said motor.

8. A. setworks for controlling the movement of the knees on a sawmill carriage including a motor for moving said knees and a brake for said motor, said setworks comprising an electrical control circuit for said motor including a brake operating means comprising a relay having opposed operating coils including a first brake neutralizing coil and a second, brake applying coil, said relay having a first position in which said brake is maintainedin neutral position and a second position in which said brake is moved to motor braking position, a first plurality of resistors, a second plurality of resistors, a source of electrical energy, switch means for starting said motor and selectively operable to connect said first coil to said source with a predetermined number of said first resistors in series withione of said coils, said switch means also connecting said second coil to said source with said second resistors in series with said second coil,,said second resistors having a total resistance greater than that of said firstresistors whereby said relay initially operates to brake neutralizing position, and means operatively connected to said knees for progressively lessening the number of resistors in series with said second coil as said knees move in response to said motor so that the voltage applied to said second coil will increase upon movement of said knees and at a predetermined point said second coil will overcome said first coil to move said relay ;to brake applying position and thus effect actuation of said brake to stop said motor.

9. A setworks for controlling the movement of the knees on a sawmill carriage including a variable speed motor for moving said knees and a speed controller for said motor effective upon actuation progressively to reduce the speed of said motor, said setworks comprising an electrical control circuit for said motor including a speed controller operating means comprising a relay having opposed operating coils including a first speed controller neutralizing coil and a second speed controller applying coil, said relay having a first position in which said speed controller is maintained in neutral position and a second position in which actuation of said speed controller is initiated, a first plurality of resistors, a second plurality of resistors, a source of electrical energy, switch means for starting said motor and selectively operable to connect said first coil to said source with a predetermined number of said first resistors in series with one of said coils, said switch means also connecting said second coil to said source with said second resistors in series with said second coil, said second resistors having a total resistance greater than that of said first resistors whereby said relay initially operates to speed controller neutralizing position, and means operatively connected to said knees for progressively lessening the number of resistors in series with said second coil as said knees move in response to said motor so that the voltage applied to said second coil will increase upon movement of said knees and at a predetermined point said second coil will overcome said first coil to move said relay to speed controller actuation position and thus effect initiation of actuation of said controller to slow said motor.

References Cited in the file of this patent UNITED STATES PATENTS 2,661,036 Balch et a1 Dec. 1, 1953 2,707,501 Craik May 3, 1955 2,807,293 Smith et a1. Sept. 24, 1957