US2636601A

US2636601A - Lumber sorter

Info

Publication number: US2636601A
Application number: US126644A
Authority: US
Inventors: Jr Harry E Bovay; Charles A Lawler; Lionel H Wheeler
Original assignee: ARTHUR TEMPLE JR; H E BOVAY JR
Current assignee: ARTHUR TEMPLE JR; H E BOVAY JR
Priority date: 1949-11-10
Filing date: 1949-11-10
Publication date: 1953-04-28
Anticipated expiration: 1970-04-28

Description

April 1953 H. E. BOVAY, JR., ETAL 2,636,601

LUMBER SORTER 3 Sheets-Sheet 1 Filed Nov. 10, 1949 INVENTORS HARRY E. BOVAY,JR. CHARLES A. LAWLER LIONEL H.WHEELER rfib r rmmsy April 1953 H. E; BOVAY, JR., EAL 2,636,601

- LUMBER SORTER 3 Sheets-Sheet 2 Filed Nov. 10, 1949 INVENTORS. HARRY E. BOVAY,JR. CHARLES A. LAWLER LIONEL H. WHEELER gHEIR A TTORNE Y P 1953 H. E. BOVAY, JR., EIAL 36,601

LUMBER SORTER 5 Sheets-Sheet 3 Filed Nov. 10, 1949 III SOURCE OF SOURCE OF ELECTRIC POWER EXHAUST TO AT MOSPH E RE UNDERl PRESSURE FIG. 9

INVENTORS.

HARRY E. BOVAY. JR. BY CHARLES A. LAWLER LIONEL H.WHEELER FIGIO Tfi R A T TORNE Y FIGS Patented Apr. 28, 1953 LUMBER SORTER Harry E. Bovay, Jr., Charles A. Lawler, and Lionel H. Wheeler, Houston, Tex., assignors, by direct and mesne assignments, of one-half to Arthur Temple, Jr., Diboll, Tex., and one-half to H. E. Bovay, Jr., consulting engineers, a partnership Application November 10, 1949, Serial No. 126,644

This invention pertains to the sorting of lumber according to its length. Certain features of the invention are applicable to the sorting of other things besides lumber and to sorting according to other dimensions than length and other functions or qualities than the dimensions of an article.

The invention is particularly adapted to sorting a mixture of lumber of difierent lengths in which one group of lumber difiers in length from the remaining lumber by a predetermined minimum length.

The invention is further particularly adapted to sorting lumber as it is moved from the saws to the storage bays by means of a conveyor of the type shown in U. S. Patent 369,550, granted September 6, 18-87, to H. B. Phillips and W. M. Whaley, such conveyor being commonly referred to as an edge sorter although the only sorting is performed manually by the operator who places different thicknesses, lengths and grades of lumber in different slots of the conveyor. According to the present invention instead of using as many slots as there are different combinations of size and grade, all of the lumber of one grade and thickness may be put in one slot and the sorting mechanism of the invention distributes the lumber of difierent lengths to the appropriate bays.

t is a principal object of the invention to provide a lumber sorter that is simple in construction, easy to operate, and inexpensive to use and maintain, yet which shall operate reliably and at a high speed.

It is a further object of the invention to provide a sorter which will have optimum operating characteristics, that is which can be operated at the maximum possible top speed with the components available for its construction and under the limitation that the sorter will operate properly independent of the speed of the conveyor within the range from zero speed up to the top speed of the conveyor at which the sorter will operate correctly.

Briefly described, a preferred embodiment of the invention may include an automatically operated gate disposed alongside a slot at the end of an opening in oneside of the slot and adapted to move into a closed position diagonally across the slot to deflect lumber from the slot through the side opening into a storage bay or to remain in an open position in which the lumber in the slot can continue on past the gate to be delivered to a different bay.. Three .switch actuators are disposed along the slot so as to be actuated by 1'7 Claims. (Cl. 20982) 2 the lumber passing by them, the switches in turn controlling the operation of the gate. The first switch actuated by the lumber as it travels along the conveyor in the slot is a normally closed switch. The next switch is a normally open switch. The last switch, whose actuator is close to the gate, is a normally closed switch. The three switches are in series in an electric circuit which may actuate a solenoid which in turn actuates a valve which controls the conduits supplying and exhausting compressed air from a cylinder within which is disposed a piston directly connected to the gate.

The middle switch actuator may be considered to be the gate operator. In order to close the gate, lumber must be present adjacent the middle switch actuator to close the circuit. The pair of switch actuators in advance of and beyond the middle switch actuator may be considered to be the measuring device. If the lumher is too long it will not be able to close the switch controlled by themiddle-actuator except when one of the other switches is open. When lumber shorter than a predetermined length travels down the slotit passes beyond the first switch actuator returning the switch to closed position while the lumber is still over the second switch actuator holding the switch in closed position and before the lumber reaches the third switch actuator so that the third switch is still in its normally closed position. With all three switches thus closed, the solenoid moves the valve so as to close the gate, and before the lumber can open the third switch and reopen the gate, the lumber hits the gate and is deflected out the open side of the slot into the bay. On the other hand, longer lumber will open the third switch before, or at least shortly after the first switch is reclosed so that the circuit will not be closed at all or at least not long enough ,to start to close thegate and the gate willremain open and the lumber will pass on through.

To make sure that such longer lumberdoes not fall off the conveyor out through the open side of the slot, the first switch actuator and the gate are constructed so as to help guidethe lumber. The first switch actuator is disposed so as to project out from the side of the slot just ahead of the opening and to deflect the lumber toward the closed side of the slot. The, gate is mounted so that in open position the free end is further removed from the opposite wall of the slot than is the end of the wall on which the gate is pivoted. The gate thus, acts as a scoop to gather in the end of any piece of lumber that 3 has gotten somewhat out of line and to guide it back into the slot beyond the gate.

The gate is mounted so that in closed position its free end rests against the opposite wall of the slot. This relieves the actuating piston of any force due to deflection of the lumber. The free end er the gate is shaped so that when closedits leading corner lies against the slot wall in order not to leave an exposed edge which might split the lumber being deflected.

It is necessary that the distance between the first and last switch actuators be greater than the maximum length of the short boards that are deflected by at least an amount equal to the distance traveled by the board in the time needed for the gate to close after theboard has left the first switch actuator less the time needed for the solenoid to move the airvalve to position tending to reopen the gate after the board strikes the third switch actuator. will start to reopen before it is fully closed. It is also Triec ssaryfthat the distance between the first and third switch actuators be not greater than -the minimum lengthof the long boards that are allowed to pass through without closing the gate plus the distancetraveled by the board in the time for 'thesolenoid to move the air valve to position to start to close the gate. Otherwise jthe lon'g' boards of minimum length will start to close the gate. For the system to operate at'all speeds from zero speed to top speed, it is thereforenecessary that there be a substantial 'di'fierencabetween the maximum length of the boards deflected and the minimum length or the'gboards passed and that the conveyoi' be operated at no greater speed than that aflwhich' thedistance traveled by the board in thetime l'a'g' period of the gate (from time of release-of switch actuator to time gate is fully closed) minus'twice the time lag of the solenoid 'is- 'eq'ual to the "minimum difference in length between short and long boards.

lt' is' alsd'necs'sary that the distance between the first'switch actuator and the gate be greater th'ari he-max mum length of the short boards by at-least'a'n amount equal ,to the distance trav e'led by' 'the board during the time taken by the *gate to close after the first switch actuator has been relea sedto reclose the switch in order that theg' ate bis-closed when the board gets there. it is'ifurthe'r-nec'ssary that the distance between the firstswitchactuator and the gate be no grea-ter 'than the distance between the first and last switch-actuators plus the distance traveled by the board in the time for the solenoid to move .the'fualvelto position tending to open the gate yafter ithfl third iswitch actuator has been depressed. otherwise the gate would reopen be- ;fore -.th e board gets to it with the possibility of splitting ,the.b,oard or letting it go by altogether.

-l;tis also necessary that the distance between the second :switch actuator and the gate be at least as great "asthe distance traveled by the board during theatime taken by the gate to close atter the second switch actuator has been depressed in order that the gate be closed when the Qtherwise the gate The requirements as to the position of the second switch actuator relative to the first and third switch actuators are merely that the second actuator be between the first and third in order that the gate be under the control not only of the middle or gate operating actuator but also the endor board measuring jact uators and that the middle switch actuator be a distance from the first actuator less than the minimum length of the short boards in order that the middle switch be closed when the first is reclosed so as to give a maximum time for the gate to close before the board strikes the third switch actuator.

The foregoing requirements concerning the distance between switch actuators and between :the first and second switch actuators and the gate are, as stated, dependent upon the speed of operation of the sorter and upon the time for the solenoid to move the valve and for the piston to operate the gate. It has been found, however, and it will be shown hereinafter, thatthe net result is that forpptimum operating characteristics the distance between first and jest switch actuators should be'equal to the minimum length of the long board s, the gate should be closely adjacent to the third switch actuatorland the middle switch actuator should be spaced from the end switch actuators by at least ,the minimum difierence between board {lengths and preferably be midway therebetween. This allows the sorter to operate properly at the magimum top speed possible for the given minimum and maximum diiierence between board lengths and for the given speed of operation of ,the solenoid and the gate, and under thelimitationthat the sorter shall operate correctly at all spe e cls iroin zero speed up to topspeed.

The sorter as just qutlined'isa single unit. By providing a plurality of units in series along t he length of the slot, each oomprisinga set of swit ch actuators, s eno a and at serert groups of lumber, each differing in length from that of the adjacent groups by aminimumpredetermined amount, clanbe sorted out from'one slot.

For a detailed description of apparatus suitable for a preferred embodiment ,of the invention'reference will now-be made "to the accompanying drawings in which: w

Figure 1 is a plan of a board sorter according to the invention, 4 W

'Figure2 isan elevation of the sorter;

Figure 3 is a plan on an enlarged scale ,of a single unit of the'sorter;

Figure 4 is an elevation of the unit shpwn'in Figure 3;

Figure 5 is a diagram showing the electric ciruit of the switches andsolenoid;

Figure 6 is a detail plan and section of a gate and its actuatingpiston and cylinde r'together with aschematicrepresentation of a-four wav valve suitable for actuating the cylinder;

Fi ure 7 is a detail in elevation of a solenoid and the val-ve'of Figure 6';

Figure 8 is a front elevation, partly 'i-nsection, of a switch and its guide-actuator suitable for use in the invention;

Figure 9 is a plan of the switch;

Figureli) is a side elevation of the switch; and

Figure 1 di r m .2 d i demeanin he $93 5 P93 1 19. 5.?-i.h nd 8%?- Re rr n 'pv t Fi u s 1 and a the i wn a ve o mpr s ng a rlimaigty .qf rollers ea i d is a sup tin framew rk H a d dPPYe h h a e g ms qv raqal yiaa '3, I4, [5 and I6 forming: the 'side walls ofthree slots l2l3, [S -l4 and I5IB.' Additional space between guides l4 and I5 provides room for additional guides if needed for expansion of the capacity of the sorter. The'conveyor rollers may be positively driven by any suitable means, for example a chain drive, as shown in the Phillips and Whaley patent, or the rollers can be disposed in a sloping plane so that lumber placed thereon'will be carried along by gravity. In the latter case, however, means should be provided to limit the top speed of the rollers and the slope must be sufficient so that before the lumber reaches the first sorting unit it will be traveling at full speed. In any case, it is desirable that the speed be controllable.

On each side of the conveyor and at a lower level are disposed a number of temporary storage bays 2ll29, each including a conveyor adapted to receive from the side of the conveyor it a particular assortment of lumber. The receiving conveyors in the bays -49 are shown as chain conveyors. The bay conveyors deliver the lumber to other conveyors which in turn carry the lumber to a stacker, storage, kilns, or loading platform for truck or rail shipment.

Each of the bays 20-29is just below a single unit of the sorter or is at the end of a slot. Thus on the far side of the sorter as viewed in Fig. 1, the slot l2--l3 has two units including gates 39, 3|, above bays 20 and 2|, and the end of the slot as represented by the fixed stop 32 is over bay 22. Slot I3I4, disposed just inside slot I2-l3 and beyond the end of slot I2-l3, is provided with a unit including gate 33 disposed above bay 23 and the end of slot l3-l4 as represented by fixed stop 34 is over bay 24. On the near side of the sorter the slot l5|5 is provided with four units including the gates 35, 36, 3'! and 38 disposed over

bays

25, 26, 21 and 28, and the end of slot l5l6 as represented by fixed stop 39 is disposed over bay 29.

As indicated in the drawing, the boards sorted into each of the bays 2B, 2! and 22 is of a different length, but having all come from the same slot l2l3, the boards in each of

bays

20, 2i and 22, may contain a similar assortment of lumber as to other characteristics such as width, thickness, and grade, depending on what is placed in the slot by the operator. A different assortment of width, thickness, and grade is sorted according to length into bays 23 and 24. Another assortment is sorted out into bays 29. As many slots and as many sorting units as necessary can be provided. If desired, enough slots and units can be provided so that the lumber in each bay is of a single kind as regards not only its length but all of its specifications. The provision of the length sorting units along the slots will in any case reduce the total number of slots required from that needed in a system not embodying sorting units.

Referring now to Figures 3 and 4, there is shown the details of one unit of the sorter, which for example may be the unit over bay 21. The conveyor rolls ill are journaled in bearings 48 supported on the framework II. The guides l5 and it are supported on this framework too, as are also the gate 3'5 and the three switches 4|, 32 and 43. The whole framework is supported well off the ground (as shown in Figure 2) so as to be above the level of the bays and their chain conveyors.

The switches M, 42 and 43 are respectively con- 7 trolled by

actuators

44, 45 and 43. Actuator 44 projects into the slot l5--l6 through an opening in guide 16. The extent to which it extends into the slot can be adjusted since the switch and actuator are mounted on a plate 41 having

slots

48 and 49 therein through which pass the screws (not shown) holding the plate to the frame so that by loosening the screws the position of the plate on the frame can be changed. Switch actuator 44, as better shown in Figures 8-10, comprises a flat steel spring secured at one end to the switch support. The face of the spring disposed in the path of the boards is diagonally disposed so as to force the boards toward the guide and away from the opening in guide l6.

Actuators

45 and 46 and the associated switches and mountings are preferably identical with actuator t4 and its switch and mounted so as to be interchangeable therewith.

Switch actuators

45 and 43 are mounted so as to project up from beneath the plane of theconveyor rollers it. Actuator 4B is disposed slightly upstream from gate 3'! in a position out of the path of travel of the gate. Actuator 44 is disposed upstream from actuator 46 a distance about equal to the minimum length of board that passes through without being deflected. Actuator 45 is about half way between

actuators

44 and 46. Switches ill and 43 are normally closed. Switch 12 is normally open. Lumber passing through slot !5-l 5 will force actuator .44 to one side causing switch 41 to open, then in passing over actuators t5 and 46, it will force them down to close switch 42 and open switch 43.

Gate 31 is secured to sleeve 50 which is rotatably mounted on a fixed shaft passing therethrough supported by bracket 5|. The gate extends vertically from the top of the guides l5 and E6 to the plane of the rollers Ill. The forward end of the face plate of the gate is beveled at 52 so as to rest flat againstguide l5 when in closed position as illustrated by gate 35. The back of the gate is reinforced with triangular plates 53 which also serve to guide boards back into the slot.

The lower end of the sleeve 50 carries an arm 54 which is'pivotally connected to piston rod 55 of the air cylinder 56 which is also secured to bracket 5|. Below the air cylinder is mounted air valve 5'! and solenoid 58 which preferably are a single fast acting unit of some type, such as that shown in U. S. Patent 2,476,519Van der Werlf and which is only schematically shown in Figures 6 and 7.

On the near side of the slot as viewed in Figures 3 and 4. there is a stop 60 which is supported from the framework by a gusset plate 6!. The stop 68 is shaped like a quadrant of an ellipse so that the near end lies in a plane perpendicular to the slot Walls. When a piece of lumber has been deflected out of the slot by the gate it strikes the far end of the stop and gradually its forward motion is slowed until when it reaches the near end of the stop'its forward motion is completely gone. In other words, the stop brings the lumber to a complete stop as far as forward velocity is concerned and the lumber falls to the bay immediately below instead of shooting off to a variable distance beyond the gate.

Referring now to Figure 5, there is shown the electric circuit for operatingv the solenoid 58. The solenoid 58 is in series with switches 4!, 42 and 43 across a suitable source of electric power not shown. When all three switches are closed the solenoid will be energized. .In the drawing there sg'ese aoi are also shown the switches and: solenoid or mother unit As many circuits as needed may besupplied in parallel from the single'source of power.

Figured-shows how a four'way' valve E'iAwill control the movement-of the piston 65 in air cylinder 56. Rotation of the movable central part 6%?- a quarterturn clockwise within the's-tationary part ill will transfer'the air pressure from the leftside of the pi'ston to'tne right sideand connect theleft side tothe atmospheric exhaust, thus causi'nguthepiston-to move tothe leit open ing: the gate 37; Aston not shown liinits'the movement of the gate in the open position, or alternatively the gate can be adjusted to be in full open position at-the'limit' of travel of the piston; The-guide iEa-ots as a stop-t limit trz'alvel of the gate to' closed position as'sho-wn inthe drawing.

Figure 7 showss'cheinatically' how the valve 5-iA may he-coIme'ot'ed- -tothe solenoid 5th. When the'solenoi'disenergized its core is drawn in and the core in turn pulls on the link to turn the valve one way. The springt iretnrns the valve to'its normalposition when the circuit through the solenoid 'sh'rohen.

Figures- B il) snow a-switch such as switch ll adapted to be-op'en'ed-by actuator it. Switch-ti is'a switch that is nroved ircin one position to another by avery'slig ht motion, such as a limit switch. The sWiteh is mounted in a threaded nipple which'isheld 'in' a hole in plate H by means Qinuts' 'iZ and 'i-BL Plate it is welded to plate 58 and braced by gu'ssetsi l and i5. Plate 7 E is also wel'ded to plate tl and is supported from plate H by spacer bars ii and it, all being welded tog'et er. Actuatofsprin'g i i is screwed at one end' toh'ar 'i'l, theother endof 'thespring normally rests againstplate ll exerting aconsiderable'forceagainst'it so that the spring does not oscillate back and'forth after a board has passed by it. Depression oitli'espring by'a boardcauses part of it to pus'hthebottom id to move-the switch, opening it in theca'sc ofswitch M. An opening Bil in plate ll permits the free end of spring M to move in 'as the spring straighte'ns' out after actuating the'switch and as the board pass'es by it.

As mentioned previously, theconstruction of switches 42' and 43 and their actuators 45 and '45 areidentic'al' to 'thato'f switch ll and its actuator it in order thatth'ey may be interchangeable, but if desired in particular installations they might be different. However, the actuators 4'5 and tls'mustextend well up into the slotin order to be sure to contact warped lumber, and actuator 44; must extend well out'into the slot to solvent a guide so that the requirements for the different switches and their "actuators are similar and usually they can be constructed alike.

It hasalready'been indicated th'at'for optimum operating characteristics the distance between the leading edges of actuators Manddfi should be about equal 'to the minirrlur'n' lengthof boards that are to passthrou'gh the unit rather than to he deflected by it, that the leading-edge of gate 3-! should be near the'leading edge of 'actua tor46 and thattlie leading edge of the middle switch actuator must be spacedfrom' the-end actuator by: atleast a distance-equal to them-iniinum difi erence'betweenboard lengths. This was found'to be'true by 'experi ment but canalsl'ibe proved by analysis as renews:

First; it will b assumed that the systeifiis' 8 apenmean'd'gate closing directions are-"concerned, that' isi that the-time for complete m'oveinentin each direction after the movement has been initiatedis the 'same.- That this is substantially correct evident fromthe fact that the inertias ofall the'pai'tsar'e constant at all times, their dist-Emcee of travelfrom open to closed position and vice'ver'sa areequal except for the spring actuators" (and here the time involved is'ne'gligible compared to other times because of shortdistance of' travel andlight partshandthe forces involvedare' the same onboth openingand closing excepdperlriapsun thedase of the solenoid which is'inovecl to tli'e gate closing "position by magnetic force'and togate'opening position by a spring (but even here it is usual to' make theseiorces about equal): There'ds' noefiect of gravity because all the parts rnove inhor'izontal directions. Kit-should be'desirable for any reason to mount the solenoid Cir the piston for vertical travel, gravity could'still'bene'glected for the force of gravity on the core and valve is small compared to themagnetl and spring forces" exerted thereohl-aiid tlidforce of gravity 'o'n'the piston is small comparedtotlie force of the air'pressure used. Furtnermorair desired theforce-of gravity in eaon'mstame couldand'usually would behalanceii out.

For assistance understanding the analysis reference may now be had to Figure 11 In the -materia=l set forth below, the following symbols-Willbe used-1 equals plus" minus 5 .equal to or'less-than equal fo or greaterthan Let I I 7 v velocity of board travel ttirrie'forsolehoidto rfiov'e' from one position to the other after board 'l'ias depressed'or released switch actuator :time for gate to movefrom one position to the other after val've'has been moved from one position to theother kz'otzdistance board travels in time t K'zoTidistance-board' travels 'in' time T p di'stance from leading edge ofse'cond switch actuator to'leadingeclgeof face of gate 7 qzdistarice between leading edges of first and secondswitch actuators s' distance between leading edges of first and third switch actuators siennaanon; leading edge of first switch actuator to leading edge of face of gate Z- m'a i-'munr length of board removed h:'minimum length of board passed b':L'*l' Consider first the conditions concerning the spacing of the first and third switch actuatorsand the position of the gate-relative thereto:

s- /Z+k+K-'Io so that the'ga'te will closebeforeit starts to reopen; I/H- (2)v sl+b+lc so long boa'rd will never start to close gate; (3) d:/Z+L+K so gate wil-l -close bfore hoard gets to it;

so gate wont reopen before board gets there.

Applying the limitation that the sorter shall operate independent of the speed up to top speed gives:

At zero speed (when k:K:O):

from (1) and (2) s 1/ d L from (3) and (4) At top speed (when lczk top; K:K top):

(7) Z+b+lc top /s:/Z+K top from (1) and (2) s-Hc topj/dJ'Z-l-K top-Ht top from (3) and (4) The quantities is and K vary directly with the speed. The right halves of ('7) and (8) show that by making d and s larger K top and is top can be increased which corresponds to increased top speed. The left halves of and (6) show that l+b is the upper limit of both s and d. Hence for optimum operation corresponding to operation independent of speed up to top speed and a maximum top speed under that limitation:

In actual practice in order to keep the third switch actuator out of the path of the gate so that the gate may extend all the Way down to the plane of the conveyor, it is desirable to make (1 slightly greater than s. However, this will only affect operation at very low speeds when k is less than 41-5 and at'such low speeds a slight opening of the gate before the board gets there will not be harmful.

Considering now the middle switch actuator and assuming that the maximum length of board removed equals the minimum length of the board removed so that gate will close before the board hits the gate;

so that the gate will stay closed until the board hits the gate.

At zero speed (when k=K=0):

(12) p fil from (11) At top speed (when k=k top; K=K top):

(13) p:/K top +top from (10) Applying Equation 9 to

Equations

12 and 13 gives:

10 and minimum'lengths of board removed are equal so that Equation 14 does hold, the minimum length of board that will permit optimum operation is one such that or otherwise stated, the sorting unit will give optimum operation for a minimum board length if the middle switch actuator is half way between the end switch actuators. In an actual case, however, the value of b is usually one, two or four feet, which is considerably less than I which starts at about six, eight or ten feet. Therefore, the middle switch actuator in these cases can be placed anywhere between the end switches as long as it is at least a distance D from the nearest end switch actuator. To avoid difiiculty in specifying the position of the middle switch in the claims, the statement therein that the middle switch actuator is disposed approximately midway between the end switch actua-v tors is here defined to mean that it lies within the range specified by condition (14), that is, it is spaced from both end switch actuators by at least the distance I).

From the foregoing description it will be apparent that apparatus has been provided achieving the stated objects of the invention. It will also be apparent that since the apparatus is designed for use in sorting lumber comprising at least two groups having a certain minimum difference of length, that certain phases of the invention comprise a new method of sorting such groups of lumber. While a preferred embodiment of the invention has been illustrated and described in detail, it is obvious that many modifications thereof could be made by one skilled in the art without departing from the spirit of the invention and it is desired to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

We claim:

1. A device for sorting lumber including in combination a slot comprising means to convey lumber forming the bottom of the slot and means at each side of the conveyor to keep lumber on the conveyor forming the side walls of the slot, said slot having an opening in. one of its side walls, said opening extending from the bottom of the slot to a height at least equal to that of the lumber as placed in the slot to be separated, a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position lying diagonally across said slot with the end of the gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open side of the slot and an open position in which it is clear of the path through the slot, a normally closed switch having an actuator disposed in the slot near the gate, a second normally closed switch having an actuator disposed in the slot at a distance from thereof furthest from said end of the opening, a third switch normally open having an actuator disposed in the slot approximately midway between the first and second mentioned switch actuators, electrically controlled means for opening and closing the gate, and electric conducting means connecting said electrically controlled means and said switches in series, whereby lumber made up of a group of boards whose minimum length equals the distance between the first and third switch actuators and a group of boards moans/o1 whose maximum length is less than said distance by a certainiincrement moving :alongithe slot in the direction from the --actuator for \the first switch toward the gate ataanyspeedifrom zero up to that equal to said distance increment divided by the time'forsaid gate to close after said circuit'is closediwill be sorted one grouprfrom the other, each boardsinthe-shorter group tmoving the second actuator while -:said first and third actuators are free-.thereby-to close vthercircuitto close the gate causing the board to be deflected outior" the slot andeach board-inthe longer groupmoving the first switch actuator itozopen circuit position to keep the. circuit open when-the board first moves the second switch actuatorand movingthe third switch actuator to openicircuit position soon enouglrto keep thegate-op-en after the board leaves the first switch actuator so that the boardpassesthe-gate without the gateiever closing.

2. A device [for sorting lumber including in combination a slot comprising means i to convey lumber. forming theloottomiofrthe .slot and means at each side of the conveyortoikeep lumbeiwon the conveyor forming the-side walls of the/slot, said slot having'anopening inone of its side walls, said opening extending from the bottom of the slot to a height at least equal tothat of the lumber as placedin the slot'tobeseparated, a gate disposed adjacent .oneend of said opening,

gate being .movablyinounted Ifor travellbetween a closed positionilying diagonally across said slot with the. end of ithergate nearest .the closed side ofthe slot beingiarther away "from saidendof the opening than'the end of theg-ate nearest the open endiof theslotand an open position in whichitlis clear oflthe path through the slot and its face nearest the slot, that is,-its back face, extendslin a'line diagonally directed with respectito the 'slot with its endfarthest away from said end of'theslot opening disposed at a distance away from the slot an'd'its endnearest said end .ofthe slot opening disposed nearthe side ofthe' slot, a normally closed switch havin an actuator disposed in .the bottom of -the-slot near the'gate, a" second normally closed switch having an actuator .disposedin the side 'of'the slot'having said'opening therein and" in that portion of saidsidefurthestfrom'said end 'offthe opening; the second said'actua-tor extending 'cliagonally atleast partway across said slotiin a direction similar "to thatof the line ofsai'djgate when in open position, saidactuator' being movable out of thepath through-said slot 'butbeing resiliently urged into the path through said slot, a third switch normallyopen havingan actuator disposed in the "bottom ofthe' slot approximately midway'between theffirstand second mentioned switch actuators, electrically controlled means for opening iand closing thegate, and electric conducting means connecting said velectrically controlled means and switches mserieawhereby lumber moving alonglthefislot'in'the direction from the actuator.for the 'firstiswitch toward the gate will be sorted accordingto' length an'd'lumber enteringthat portion of the slot adjacent the opening will be guided towar'd the closed side of the slot by the second-saidactuatorand lumber leaving that portion :of the slot adjacent the opening will .be guidedintothe closed part of the slot by the back faceof thelguide.

3. A device for sorting lumber including in combination av-slot: comprising-.means to convey lumber forming: the bottoml'of the-slot'and means at each side of the conveyor-rtob lceepzlumber on the conveyor forming the side walls of the slot, a plurality of side wall'openings spaced apart along the length of the slot, each of said openings extending ifrom thebottom .dfthe slot to a height at least equalto that of the lumber as placed in the slot to be separateda fixed guide lying diagonally across one endof the slot adjacent to the end of one of said openings, said guide having its end furthest from said side wall of the slot disposed turthestfrom the end of the slot, and guide means disposed adjacent each of the remainder of said openings inlthe sidewall of the slot, each of saidguidemeans comprising a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position lyingdiagonallyiacrosssaid slot with the end of the gate nearest the closed side of the slot beingfartheraway from said end or" the opening than the end of the gate nearest the open side of the slot and an open position in which it is ciearof thepath through the slot, a normally closed switch: having an actuator disposed in the slot near the gate, a second normally closed switchihaving an actuator disposed in the slot at a distancefrom' the. first mentionedswitch actuator Lonthe sidethereof furthestfrom said end of the opening, :a :ithird-switch normally open having an' actuatoridisposed in the slot approximately :midway between the first and second mentioned :"switch .actuators, electrically controlled means for opening .and closing the gate, and electric conductingmeans connecting said electrically controlled'means and said switches in series, the distance between tthe first and second mentioned switch actuators of each of saidguide means :ibeing'ismall'er :;by i the same icertainincremerit than that hetween the like pair of actuators of theadjoining; guide means onthe side thereof nearest the fixed-guide. i.- e., the downstream side, and larger 'bythe same certain increment than that between the like pair of actuators of the adioining guide means on the other side thereof, i .-1e., the upstream-side-whereby lumber made up of a, pluralityiofigroups of boards equal in number to the number of said guide means, each group of boards being approximately of one length equal to the distance between a dilierent one of saidpairs of actuators and a further group of boards approximately of one length equal to the distance between the pair said actuators that are the :shortest distance apart minus said certain increment of distance when moving along the slot indownstream direction at any speed from zero up to that equal to said increment'of distance divided by the time for each of'said gates to close-after-its'circuit is closed will be sorted one group from the other, boards in each group passing "through all'guide means Whosetpairs of actuators are no further apart than the length of the boards without closing the gatesthereof hutibeing-de'flected*outrof the slot by-theegate of the firstiguide means whose pair of actuators is spaced farther apart than the length of'the'boarda orin' the case of the largest group by the fixed guide means.

4. A sorting machine adapted to sort a mixture of groups ofboards each of which groups difiers length from the next longer board by a predetermined minimumincrernent, said sortin'g machine including'a'slot comprising a pair of spaced apart :substantially parallel vertical walls: forming thewsidestof the slot, said slot having :as -many side wall openings spaced apart along the lengthuof'theslot asthere are groups of boards, :said openings extending from the slot bottom at least to the height of a board placed in the slot, motor driven means of adjustable speed in the slot bottom for conveying the boards along the slot, at sorting unit adjacent each opening comprising an actuator, a normally closed switch actuated thereby, said actuator being adjustably disposed in the slot, a second actuator, a normally closed switch actuated thereby, said second actuator being disposed in the slot upstream from the first actuator an adjustable distance, a third actuator, a normally open switch actuated thereby, said third actuator being disposed in the slot between said first and second actuators, a gate mounted for movement between a closed position in which it shunts boards out of said slot through the opening in the slot wall and a position in which it is out of the path of board travel through said slot, electric means in series with said switches for controlling the movement of said gate, the position of the first switch actuator being adjusted so that it is disposed closely adjacent said gate, the position of the second switch actuator being adjusted so that it is disposed a distance upstream from the gate equal to the minimum length of the boards of those groups which are to pass through the unit without being shunted out of the slot, the speed of said motor driven means being adjusted so that the speed of board travel along the slot is not greater than the ratio of the smallest of said increments divided by the time required for actuation of the gate from one of said positions to the other after said switches have been moved between a circuit closing position and a circuit opening position.

5. A sorting machine adapted to sort a mixture of groups of boards each of which groups differs in length from the next longer board by an equal predetermined minimum increment, said sorting machine including a slot comprising a pair of spaced apart substantially parallel vertical walls forming the sides of the slot, said slot having as many side wall openings spaced apart along the length of the slot as there are groups of boards, said openings extending from the slot bottom at least to the height of a board placed in the slot, motor driven means of adjustable speed in the slot bottom for conveying the boards along the slot, a sorting unit adjacent each opening comprising an actuator, a normally closed switch actuated thereby, said actuator being adjustably disposed in the slot, a second actuator, a normally closed switch actuated thereby, said second actuator being disposed in the slot upstream from the first actuator an adjustable distance, a third actuator, a normally open switch actuated thereby, said third actuator being disposed in the slot between said first and second actuators, a gate mounted for movement between a closed position in which it shunts boards out of said slot through the opening in the slot wall and a position in which it is out of the path of board travel through said slot, electric means in series with said switches for controlling the movement of said gate, the position of the first switch actuator being adjusted so that it is disposed closely adjacent said gate, the position of the second switch actuator being adjusted so that it is disposed a distance upstream from the gate equal to the minimum length of the boards of those groups which are to pass through the unit without being shunted out of the slot, the speed of said motor driven means being adjusted so that the speed of board travel along the slot is equal to the ratio of said presolenoid connected to the 14 determined minimum increment divided by the time required for actuation of the gate from one of said positions to the other after said switches have been moved between a circuit closing position and a circuit opening position.

6. A device for sorting lumber including in combination a slot comprisingmeans to convey lumber forming the bottom of the slot and means at each side of the conveyor to keep lumber on the conveyor forming the side walls of the slot, said slot having an opening in one of its side walls, said opening extending from the bottom of the slot to a height at least equal to that of the lumber as placed in the slot to be separated, a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position lying diagonally across said slot with the end of the gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open side of the slot and an open position in which it is clear of the path through the slot, a normally closed switch having an actuator disposed in the slot near the gate, a second normally closed switch having an actuator disposed in the slot at a distance from the first mentioned switch actuator on the side thereof furthest from said end of the opening, a third switch normally open having an actuator disposed in the slot between the first and second mentioned switch actuators, electrically controlled means for opening and closing the gate, and electric conducting means connecting said electrically controlled means and said switches in series, said electrically controlled means comprising a piston connected to the gate, a cylinder in which said piston moves, a four-way valve controlling the admission and exhaust of fluid under pressure to and from said cylinder on opposite sides of the piston, and a valve and controlled by said switches. 7. In combination, a slot having an opening in its side wall, a gate disposed adjacent one end of said openingsaid gate being movably mounted for travel between a closed position lying diagonally across said slot with the end of the gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open side of the slot and an open position in which it is clear of the path through the slot, a normally closed switch having an actuator disposed in the slot near the gate, a second normally closed switch having an actuator disposed in the slot at a distance from the first mentioned switch actuator on the side thereof farthest from said end of the opening, a third switch normally open having an actuator disposed in the slot between the first and second mentioned switch actuators, electrically controlled means for opening and closing the gate, and electric conducting means connecting said electrically controlled means and said switches in series, each of said actuators comprising a member normally extending into said slot and means resiliently urging said member further into the slot and a stop limiting the motion of said member into the slot under the influence of said means urging the member into the slot so that said member normally presses against said stop, whereby after said member of any one of said actuators has been moved in a direction out of said slot 35 without:oscillation backs and *forth l in andout' of the slot.

8. In combinatioma lumber conveyor, two non mally closed switches, onenormally open switch, an electric circuit connecting said switches in series, actuating means for each of said switches disposed adjacent said conveyor to actuate each of said switches once byall lumber on the conveyor -passing thereby, theactuating means'for the normally openswitch being 'disposedbetween the other twoactuating means with respect to the directionof travel'of lumber on said conveyor, ejection means for causing lum-ber toleave the conveyor, and control means in series with said circuitto actuate-said ejection means when said circuit is closed through-said-switches to energize said control means an'dito return said ejection means to its deactuatedposition when said circuit is opened by any one of. said switches, said circuit being thasolercircuit through which said control means canbeenergize'd, said-two actuating means for thernormallyclosed switch actuators being spaced apart azdistance equal to the minimumlength of lumber that will pass by said two actuating means withoutactuating said ejection means-and said actuating means for the normally open switch being disposed between said two actuating means and spaced therefrom by at least the" minimum'difference inlength between lumher that will pass Joy all of said actuating means without actuating saidejection means and lumher that istto be-caused'to leave the conveyor by said ejection means.

9. In-combination alumberconveyor, two normallyzclosed switchescne normally open switch, an electric circuit connectingsaid switches in series: actuating means for each of said switches disposed adjacent saidconveyor to actuate each of said switches-once byalllumberon the conveyor'passingthereby, the actuating means for l the normally open switch being disposed between the other two actuating means with respect to the direction of ftl'fiVEl'Of'lUfllbBl on'said conveyor, ejection means for causing lumber toleave the conveyor, said ejectionmeans including a gate mounted so as to be movable between. a position preventing lumber from passing along the conveyor-in which-position the lumber is forced off the conveyor and a position in which the gate is out of the path oftravel of the lumberrand control-means in serieswith said circuit to actuate said ejection means when said circuit is closed through -said=switches to energize said control means "and to return said ejection means to its deactuated position whensaid circuit is opened lay-any one ofsaid switches, said. circuit being the sole circuit through which said control means cache-energized.

10. In combination, --a lumber conveyor, two normally closed switches, one normally open switch, an electric circuit connecting said switches in series, actuating means for each of said switches disposed adjacent said conveyor to actuateach of said switches. once by all lumber on the conveyor passing thereby, the actuating means for the normally open switch being disposed. between the other two actuating means with respect to the direction of travel of lumber on said conveyor, ejection means for causing lumber to leave the conveyousaid ejection means including a gate mounted so as to be movable between a position preventing lumber from passing along the conveyoriin which positionthelumber is forced off the conveyor;andrapositiona which the. gatev is outpfythezpathpf' travelof. the lumber, said gate being disposed adjacentthe-one or said switch actuating means that is furthest downstream with respect to motion of'lumber-along the conveyor, and control means in series with said circuit to actuate said ejection means when said circuit is closed through said switches to energize said control means and to return said ejection-means to its deactuated position when said circuit is opened by any oneof said switches, said circuit being the sole circuitthrough which said control means can be energized.

11. A device for sorting lumber including in combination a slot comprising means to convey lumber forming the bottom of theslot and means at each side of the conveyor to keep lumber'on the conveyor forming the side walls of the slot, said slot having an-opening in one-of its side Walls, said opening extending from the bottom or" the slot to a height at least equal to that-of the lumber as placed in the slot to be separated, a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position in which its face nearest the other end of said opening, that is, its front face, lies diagonally across said slot with the end of said front face of the gate nearest the closed side of the slot being'farther away from-saidend of the opening than the end of said front face of the gate nearest the open end of the slot and-an openposition in which it is clear of the path through the slot and its face nearest the-slot, that is,'its back face, extends in a line diagonally directed with respect to the slot with theend of said back face of the gate farthest away from said end of the slot opening disposedat a distance away from the slot and the end of said back face of the gate nearest said end of the slot opening disposed near the side of the slot, and means for opening and closing said gate according to the length of lumber moving along the slot toward the gate so that the gate is closed to deflect shorter lumber out of the slot throughsaid opening and so that the gate is open to pass longer lumber along the slot, the back side of the gate when in open position guiding said longer-lumber intothe slot as itleaves that portion of the slot adjacent said opening in the side wall thereof.

'12. A device for so-rting'lumber including in combinations, slot comprising means to convey lumber forming the bottom of the slot and means at each side of the conveyor to kee lumber on the conveyor forming the side walls of the slot, said slot havingan opening in one of its side walls, said opening-extending from the bottom of the slot to a height at least equal to that of the lumber as placed in the slot to be separated, a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position in which it lies diagonally across said slot with the end ofthe gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open end of the slot and an open position in which it is clear of the path through the slot, andmeans for opening and closing sai d gate according to"l7heglength of lumber moving along the slot toward the gate from the portion of the slot near the other end of said opening, said means including an actuator disposed in the side of the slot having said opening therein-and in that portion of said side farthest from said end. of the opening, saidaactuator extending diagonallyhat'leastlpa-rt way across said slot-inn direction transverse to that of the upstream face of thegate when inclosed -position,--said actuator being movable out of the path through the slot but being resiliently urged into the path through the slot whereby lumber moving along the slot in the direction from said actuator toward said gate and entering that portion of the slot adjacent the opening will be guided toward the closed part of the slot by said actuator.

13. A device for sorting lumber including in combination a slot comprising means to convey lumber forming the bottom of the slot and means at each side of the conveyor to keep lumber on the conveyor forming theside walls of the slot, a plurality of side wall openings spaced apart along the length of the slot, each of said openings extending from the bottom of the slot to a height at least equal to that of the lumber as placed in the slot to be separated, and guide means disposed adjacent each of said openings in the side wall of the slot, each of said guide means comprising a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position lying diagonally across said slot with the end of the gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open side of the slot and an open position in which it is clear of the path through the slot, a normally closed switch having an actuator disposed in the slot near the gate, a second normally closed switch having an actuator disposed in the slot at a distance from the first mentioned switch actuator on the side thereof furthest from said end of the opening, a third switch normally open having an actuator disposed in the slot approximately midway between the first and second mentioned switch actuators, electrically controlled means for opening and closing the gate, and electric conducting means connecting said electrically controlled means and said switches in series, the distance between the first and second switch actuators of each of said guide means being smaller by the same certain increment than that between the like pair of actuators of the adjoining guide means on the downstream side thereof, downstream referring t motion along said conveyor in the direction from the second said switch actuators toward the first said switch actuators, and larger by the same certain increment than that between the like pair of actuators of the adjoining guide means on the other side thereof, i. e., the upstream side.

14. A device for sorting lumber including in combination a slot comprising means to convey lumber forming the bottom of the slot and means at each side of the conveyor to keep lumber on the conveyor forming the side walls of the slot, aplurality of side wall openings spaced apart along the length of the slot, each of said openings extending from the bottom of the slot to a height at least equal to that of the lumber as placed in the slot to be separated, and guide means disposed adjacent each of said openings in the side wall of the slot, each of said guide means comprising a gate disposed adjacent one end of said opening, said gate being movably mounted for travel between a closed position lying diagonally across said slot with the end of the gate nearest the closed side of the slot being farther away from said end of the opening than the end of the gate nearest the open side of the slot and an open position in which it is clear of the path through the slot, a normally closed switch, an actuator for said normally closed switch disposed in the slot near the gate, a second normally-closed switch, an actuator for said second normally closed switch disposed in the slot at a distance from the first mentioned switch actuator on the side thereof furthest from said end of the opening, a normally open switch, an actuator for said normally open switch disposed in the slot between the first and second mentioned switch actuators, electrically controlled means for opening and closing the gate, and electric conducting means connecting said electrically controlled means and said switches in series, the distances between said first and second switch actuators of each of said guide means being successively longer progressing along said slot in the direction from the second mentioned switch actuators towardthe first mentioned switch actuators.

15. In combination, a lumber conveyor, two normally closed switches, one normally open switch, an electric circuit connecting said switches in series, actuating means for each of said switches disposed adjacent said conveyor to actuate said switches whenever lumber on the conveyor passes thereby, the actuating means for the normally open switch being disposed between the other two actuating means with respect to the direction of travel of lumber on said conveyor, ejection means for causing lumber to leave the conveyor, and control means in series with said circuit to actuate said ejection means when said circuit is closed through said switches to energize said control means and to return said ejection means to its deactuated position when said circuit is opened by any one of said switches, said two actuator means for the normally closed switch actuators being spaced apart a distance equal to the minimum length of lumber that will pass by said two actuating means without actuating said ejection means and said actuating means for the normally open switch being disposed between said two actuating means and spaced therefrom by at least the minimum difference in length between lumber that will pass by all of said actuating means without actuating said ejection means and lumber that is to be caused to leave the conveyor by said ejection means.

16. In combination, a lumber conveyor, two normally closed switches, one normally ,open switch, an electric circuit connecting said switches in series, actuating means for each of said switches disposed adjacent said conveyor, said actuating means being disposed in a line with each other parallel to the length of said conveyor so as to actuate each of said switches once by all lumber on the conveyor passing thereby, the actuating means for the normally open switch bein disposed between the other two actuating means with respect to the direction of travel of lumber on said conveyor, ejection means for causing lumber to leave the conveyor, means responsive to closure of said circuit to actuate said ejection means, and means at all times responsive to opening of any one of said switches to return said ejection means to its deactuated position, said actuators for said normally closed switches being spaced apart a distance equal to the length of the shortest lumber that will pass thereby on the conveyor without closing said circuit.

1'7. In combination, a lumber conveyor, two normally closed switches, one normally open switch, an electric circuit connecting said switches in series, actuating means for each of said switches disposed adjacent said conveyor to actuate said switches whenever lumber on the 19 conveyor passes thereby, the actuating'meansior the normally open switch being-mposed'hetween the other two actuating means with respect to the direction of travel of a stream of lumber onsaid conveyor, ejection means for causing lumber to leave the conveyonsaid ej ection meansincluding a gate mounted so as to he movable between a position preventing lumber from passing along the conveyor in which position the lumber is forced off the conveyor and apositionin which the gate is out of the path of travel of thelumber, said gatebeing disposed adjacent theone of said switch actuating means that is farthest downstream with respect to motion of lumber along the conveyor, .rneans responsive to-closure of said circuit to actuate saidejection meanaand means responsive toopening of said circuit to return said ejection meansitoits deactuated Dosition.

Y-v-HARRY E. BOVAY, J R.

CHARLES A. LAWLER. LIONEL H. WHEELER.

References Cited in thefile of this patent UNITED STATES PATENTS Number 7 Name Date 1,220,799 Tanner Mar. 27, 1917 131065-32 Onstad Mar. 26, 1929 1,986,512? Denton Jan. 1, 1935 2,421,484 Diamond June 3, 1947 2,488,037 'Rupley Nov. 15, 1949