US2821220A

US2821220A - Log feed mechanism

Info

Publication number: US2821220A
Authority: US
Inventors: Thomas W Nicholson
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-02-01
Filing date: 1954-02-01
Publication date: 1958-01-28
Anticipated expiration: 1975-01-28
Also published as: GB840062A

Description

Jan. 28, 1958 T, w, NlHoLsoN 2,821,220

LOG FEED MECHANISM s Sheets-sheet 1 Filed Feb. 1. 3.954A

Jan.. 28, 1958 T. w. NICHOLSON A2,321,220

LOG FEED MECHNISM v Filed Feb. l, 1954 1 5 Sheets-Sheet 2 Jan. 28, 1958 T. w. NxcHoLsoN LOG FEED MECHANISM 5 Sheets-Sheet 3 Filed Feb. l, 1954 Jan. 28, 1958 T. w. NICHOLSON Los FEED MECHANISM 5 Sheets-Sheet 4 Filed Feb. 1, 1954 Jan. 28, i958 11W. NICHOLSON 2982L22 LOG FEED MECHANISM 5 Sheets-Sheet 5 Filed Feb. l. 1954 INVENTOR. 740/1445 n/ AMA/oz 50/V A 7 Toen/6W5 United States Patent O LOG FEED MECHANISM Thomas W. Nicholson, Seattle, Wash. Application February 1, 1954, Serial No. 407,362 9 Claims. (Cl. 144-249) This invention pertains to mechanisms for feeding logs to processing machines and is particularly intended to feed logs to a machine for removing bark from them. By such mechanism logs are fed lengthwise and nonrotatively through such a machine.

Machines of various types have been devised for removing mark from logs, but the present log feeding mechanism has particular utility for use in conjunction with a log barking machine of the type which includes a rotary ring through which a log is fed for engagement by barking tools carried by such ring and moved orbitally around the log. Feed mechanism for use with such a machine must be capable of holding a log against appreciable lateral displacement, of preventing rotative movement of the log and of effecting uniform progressive lengthwise movement of the log through the barking machine, and it is a principal object of the present invention to provide mechanism having these attributes.

A further important object of the invention is to provide such mechanism which will be equally effective for feeding large logs and small logs and which can be adjusted readily for accommodating logs of different sizes.

Especially is it an object of such mechanism to be able to hold a log firmly against rotation about its axis by the use of apparatus of simple construction and which will afford minimum resistance to longitudinal movement of the log and hence will feed the log elciently.

Great force is exerted on a log in removing the bark from it by the use of such a machine, and consequently such feed mechanism must be rugged to withstand the abuse to which it will be subjected during the barking of large and heavy logs. Also, it is important that such mechanism be designed to resist wear resulting from its use and for this reason it is desirable to have as little relative movement as possible between the surface of a log and the parts of the feed mechanism with which it comes into contact.

In accomplishing these objects the log feed mechanism incorporates positively moving log carrier means in the form of chains or live rolls, for example, in combination with upper adjustable hold-down devices such as a plurality of rotary ribbed heads which engage a log at circumferentially spaced locations. Both the carrier or transport means and the rotary hold-down heads grip the log in a manner to resist its rotative movement while producing little or no appreciable resistance to lengthwise movement of the log. A more effective feed is obtained by gripping the log at opposite sides of the barking mechansm so that the log is both pushed and pulled through the barking machine while held firmly in the manner described at both sides of the barking mechanism.

Additional objects and advantages of the log feed mechanism will be discussed n the following specific description of representative types of such mechanism shown in the drawings.

Figure 1 is a plan view of a preferred type of log feeding mechanism incorporating a chain type carrier, and

ZZLZ Patented Jan. 28, 1958 Figure 2 is a vertical sectional view through such mechanism taken on line 2 2 of Figure 1.

Figure 3 is a fragmentary top perspective view of a portion of such mechanism.

Figure 4 is a plan view of a different type of such mechanism incorporating a chain-driven flight type of carrier and utilizing different hold-down devices.

Figure 5 is an enlarged transverse sectional view through the mechanism taken on lines 5 5 of Figures 4 and 6. Figure 6 is a fragmentary longitudinal vertical section through the carrier along lines 6 6 of Figure 5.

Figure 7 is a plan view and Figure 8 is a side elevational view of still a further type of log feeding mechanism incorporating a live roll carrier and hold-down devices like those in the form of Figure 4. Figure 9 is an elevation view of the apparatus showing the hold-down device taken on line 9 9 of Figure 7, and Figure 10 is a top perspective view of the hold-down device illustrating the manner in which it engages a log. Figure 1l is a side elevation view of one type of live roll used in the carrier of such mechanism with parts broken away, and Figure l2 is a transverse sectional view through such a roll on line 12 12 of Figure 11. Figure 13 is a side view of a different form of live roll which may be used in the carrier of such mechanism, section through such roll along line 14-14 of Figure 13.

Figure 15 is a transverse section showing another form of device; Figure 16 is an enlarged section on line 16-16 of Figure 15.

As has been stated, the log feeding mechanism of the present invention finds its greatest utility in feeding logs lengthwise and nonrotatively through a log barking machine of the rotary ring type. Such a barker is illustrated representatively in Figures l, 2, 47 and 8 as incorporating a rotary ring 1 which is mounted rotatively in a supporting ring 10. This latter ring is mounted in a frame 11 which is guided for vertical movement in ways 12 as shown in Figure 2. This frame can be adjusted vertically by operation of a iluid cylinder 13 moving the frame supporting rods 14 vertically to dispose the center of the

rings

1 and 10 coaxial with a log carried by the log feeding mechanism. The barking ring 1 is rotated to perform the barking operation by the chain 15 which is driven by the electric motor 16. The ways 12, cylinder 13 and motor 16 are all supported on suitable framework 17.

Figures 1. 2 and 3 show the preferred type of holddown mechanism. In this instance the log L shown in Figure 2 rests directly on and is cradled between two chains 2 extending in spaced parallel relationship axially of the barking machine ring, and hence lengthwise of the direction in which the log is to be moved through such ring. Preferably these chains are spaced apart a distance approximately equal to the radius of a log of medium size from which the bark will be removed by the barking machine. When carrying even the smallest log to be fed through the barking machine, therefore, the lowest portion of the log will not extend much below the chains, so that the weight of the log will not exert a great force tending to wedge the chains apart. At the same time, the spacing between the chains will be Sucient so that when the largest log to be processed is resting on them such log will be engaged at locations spaced apart enough to afford adequately stable support to the log to avoid any appreciable chance of the log rolling olf the chains when held down properly.

The entire weight of the log will rest on the chains 2 of the log carrier section on the feed side of the barking machine as the log is being moved into it, and the log will be supported jointly by such chains and by the chains 2 of the carrier section at the discharge side of the log and Figure 14 is a transversel "iasanaao barking machine asthe log progresses through it. Since thelog is thus carried bodily bythe chains engaging the log over a great longitudinal extent, the frictional engagement between thelog and chains produces a great resistance to'movement 'of such chains `relative to vrthe log. Consequently, there is little danger of 4thecha'in's slipping along the log instead'of moving vthe log positively inV synchronism withthe lchains, because 's'uch s'lippagecouldioccur only if 'the log were 'subjected to avery great force opposing its lengthwise movement. This chaintypefoflog carrienthereforefeedsthe lo'g through the barkingmachine very reliably'at apredctermined-constantrate'of speed. y

The

chains

2 and 2 are supported 'in parall'elchannels on i'plates `beneath Vvthem Vand 'extend `v`between "spockets carried by cross shafts -as show uinFi'gs. 1, 2 'and 3. VEach crlss :shaft 'carries two sprockets, on'e"for"ea`ch chain, and4 the ytwo""sprockets on Yeach "shaftjar'e "interconnected and dnitely"`spaced by aheavy hollow "'axlethrough which "the cross shaft extends. The fcorre'spnding spfeckets at one end 'of chains A2 are rotated positively bythe 'shafticarrying them,'whichis turned bycha`in 22 driven vhy the motor'723, Ias 'shown nlFigure 1. 'Chains 2 willferitendaxiallyof the barking ring `for iaisubstantial distanceadpreferablyover nearly the' 'full lengthf of a log ifL average lergth'frorn 'which thev bark' 'is Vto" be removed bythe barking'r'nachine. Chains of such'length will insne-'that they 'exertv aliirm, vreliablefeedng"grip on"'a`lg`l'tol5e barked. The chains'Z' atthedischarge side fof-the barking'machineneed notbe s'long 'as'fthe chains'ratth'e feed'side 'of the machine, andtheylare supportedfand Vdriven generally in the'saine manner. i

Beyond the discharge ends of chains 2' live'rolls'24 may be profvided'tocar'rythe brked ylogaway fromthe barking machine. These rolls may ybe driven byinterconnecting -chains- 25 and a' chainY 26 may connect'the shafto'f 'rollv24"closest to chains "2 "and the 'adjacent sprocket-shaft 27- of' such chains. fBylsuch interconnection thechins Z'fand-r'olls 24will' all be drivenat the same speed and at a speedsynchronized with the speed'of the feedchains 2. Suitable lsupporting structure will, of course, be provided 4for the chain sprocket shaftsand .the roll shafts, as indicated'in'the drawings.

The

chains

2 and 2" will deter-movement'of thelo'g` in a generally" horizontal direction transversely VAof'the chains,`fbut the weight ofthe log lmay not be sufiicient to insure thatit will'befheld ldown in frm engagement with the'chains under stresses exerted on Vit by the hai-king operation.- -Consequently,a plurality'of'rotary'hold-down (50 devices are arranged above the chains 2 and 2' toengage thefnpper'portion `ofa log. P-referably'these rotary hold-down devices 3f are-'rotary heads arranged'in pairs, one' fate each` side 1 of-` a 1vertical A plane extending e lengthwise and centrallyof--thelog carrier. Thev rotary heads of each pair should be spacedeapart a substantialdistance sothat 'they' will engagelspced-locations on the upper surface vof the log.

Each' rotary head 31is journaled on the end of an arm, which-maybe a lever arm 30 fswingableeabout a supporting'v pivot 31. Y1Irn'the rotary hold-down head arrangement shoWnfinfFigures -1, Zand-3, swinging ofithe lever 30 is enec'tedfby afluid piston IVand* cylinder device 32,'one end :of `whichf-is connectedby pivot'33 to the arm ,30 at va location between -theilhold-down head'3 and the ar-m` pivot 31. The other end of the piston kand cylinder deiliceV is connected -bya pivot V34 to a stationaryreaction bracketuon theframework 255,- which supports the holddown mechanism. Contraction of theffluid piston and cylinder 'device 'will therefore swing; thearm downward about Apivot 31 'to' press the *hold-down head' 'iirmly against'alo'g while'eirtension 'movement of" such device will--swi-ng'the lihold-fcl`o`wn"`head'awayfrom the log'to vhold-down heads "may,

4 Any number of pairs of such lever-mounted rotary of "course, be provided,`but Vit has been found that two pairs of such heads adjacent to the infeed side of the barking machine and two pairs of such heads adjacent to the discharge side of the barking machine, as shown in Figure 1, are adequate to hold a log rmly in contact with the

chains

2 and 2. For usual control the `pistonfand cylinder devices 32 for the two levers .of --each .pair :of `such hold-down heads may be connected together, but each individual device should also-beioperable-separatelytocnable a log to be-shifted laterally by pressureof yone `device. .Both hold-down heads of any pair can 'thus be moved upward or downward simultaneously .'and'independently of such movement of any other pair of heads, or any one holddown device can be moved separately at will. Also because fluid-actuated devices are employed, such as air cylinders, each hold-down head ymay-iexertsubstantially-the same forceonv la log irrespective-.of the swung .position ofv the 'hld-down lhead supporting `arm :30 within'trather wide-limits.

By'the use of rotary hold-downdevicesl adequate-pressure may beexerted onalog-withoutcreating appreciable resistance'to movement of the-log .lengthwise effected by the'logc'arrie'r such as chains'2.-and.`2l'. It .is important, howevenwhen such feed mechanism ;is;usedtoffeed logs to" a `rotar'y "ringibarker, fforthev feed mechanismv to restrain rotation'fthe log. "Botht'helog carrier `and the hold-down'devicesfcontribnteto'this action. The chains engageithe logondongitudinal.elements and themselves produce "-considerahle lresistance `to rotation of -the log whenitfis' pressed va'gainstf them'by the hold-down devices. The"holdldown"devices alsoare formed to grip theflog firmly for'preventin'g its rotation. A friction wheel surface,-such`as' aruhber'tire, can be used.

Particularly in FiguresZand 3 a'rotary hold-down devicefheadsshown as incorporatngsseveral spaced annularfribscooperatively/conforming generallyto the arcuate contour-*f thelog-spei'iphery ln'thisgparticlar instancethefrotary headfofsnehhold-down de'vice may befasingle in'fhel having-a ylgrooved peripheryforming tl'iese'ribsV or `snchrbsrnayA be formed byfthefperipheries of parallel; coaxial-disksf '36 ofdiierent diameters' which are independently Ajol-lrnaled on fthe yshaft carried by' arrn 30. Such rotaryhold-'downhead disks are'siciently thick -soI thattheylwill f'not'fyield'appreciably under`later`al pressureexertcdfc'n them-by'ftendency ofthe log to rotate,

withzconeentrated pressure. The vribs 'spacedaxially'of the: rotary` h'eadimprove the' contact :between such" head displacementiofi'thelog `traftnsversely off-its length. Such log-'movementiresistingiloontact@is 'improved-for' logs of4 diterentssize: by sha-pingzltheribbed-rotary-heads tapered rotatedbycontactvwitha log, barlcdebris'willlberemoved l from the v spaces hetweennthe disks.

ln v:operation y-off-theI feed mechanismsshown Jin Figures l, 2 and 3-al0gwill-becarried to the "chainsvl'and movementofnthcse-c-hains will' draw `theilog progressively farther onto-them. :Beforeltheaendofthe logireaches 32' will be extended to ra-ise'therotary hold-downfheads 3 of such pair.and-perhaps-ofthe other pairsifl'the log Vahead hasclearedf-thebarkingring.v Aslt-he-'endfbf Ythe log passes beyond` each `pair -aof f'hold-.down lvdevices, i:the heads of each -pair inturnwill ybe loweredtintofengagement wi'ththellogaandfpres-surewillbe frri'aintainedwinathe:

cylinders .of the luidwactuators -to exertcontinuouspositive hold-down pressure on the log until:itsfrrailingiendnhas movedbeyond-the barking `ring.

gflhe operation -of r:theVIA log greed r mechanismV :shown in A Figures 4, and 6 is similar to that described above. In this instance, however, instead of the log resting directly on carrier chains, the chains 4 do not support any of the weight of the log. Instead, such claims merely constitute interconnecting members to space and drive log supporting generally planar, plate-shaped ights 40. The upper edges of these flights are of generally V shape and have projections or teeth arranged at intervals along the length of such upper edge to effect a secure grip on the log. The chains are connected to projections 41, respectively, extending downward adjacent to opposite ends of the flight. Lengthwise movement of the chains 4 will, of course, be coordinated, and by connecting such chains in spaced relationship to the ights such flights will be held in positions with their planes perpendcular to the chains as they travel around the sprockets at the opposite ends of the chain loop.

The supporting mechanism for the ilights 40 includes posts 42 which support I-beam rails 43 extending parallel to the direction of movement of the chains. Wear strips or tracks 44 are mounted along the upper anges of the rails 43 on which the overhanging opposite ends of the flight 40 rest, respectively. Each end of each flight is provided with a shoe 45 ransversely of the flight plane to provide a sliding surface of suflicient extent in the direction of flight movement to prevent tilting of the ight under the inuence of the force couple resulting from the pull of the chains 4 below the frictional resistance occasioned by contact of the shoes with the wear strips 44.

In this form of log feed mechanism the hold-down devices are somewhat different from those previously described, and these are shown best in Figures 4, 9 and 10. In this instance the lever arms 5 are mounted on pivots located generally centrally between their ends. The adjacent ends of each pair of lever arms carry rotary hold-down heads 51 rotatable on axles extending lengthwise generally in continuation of the lever portions carrying such rotary heads. The lever portions at the other sides of the pivots respectively are disposed at an angle to the rotary head carrying portions of the lever arms, so that such rotary head carrying portions are generally upright while the portions of the lever arms to which the control force is applied extend generally horizontally.

To the swinging ends of the generally horizonal lever portions are pivotally connected piston and cylinder fluid actuators 52, which are supported from the mounting structure 53 by pivots 54. When the actuators are contracted, therefore, the rotary head carrying lever portions will be swung away from each other to retract the hold-down heads 51. Conversely, extension of the actuators will swing the levers to move the hold-down heads inward into contact with a log L. In Figure l0 the holddown levers are illustrated in retracted positions in full lines and in holding positions in broken lines. When in such holding position, uid under pressure will be impressed upon the fluid-actuated devices so that the force of the rotary hold-down heads will be maintained against the log.

By journaling such rotary heads on axles extending generally in prolongation of the lever portions, the axis of rotation of each hold-down head will extend generally parallel to a tangent to the log at the location of holddown head contact with it, as illustrated in Figure 9, and the rotary heads of each pair of hold-down devices will engage the log at spaced locations. While, as previously discussed, the rotary hold-down heads may be composed of a plurality of independently journaled disks, a reasonably satisfactory grip of the peripheries of the hold-down heads on the log opposing its rotation about its longitudinal axis may be afforded by spaced annular ribs 55 formed by grooving the peripheries of the rotary heads 51. Preferably these ribs taper to a reasonably sharp edge and the intervening groove may be V-shaped in cross section, as shown best in Figure 9.

of considerable extent- The log barking machine with which'the feed mechanism shown in Figures 4, 5 and 6 may be used, as illustrated in Figures 4 and 9, is the same as that described in connection with the log feed mechanism of Figures 1, 2 and 3, and consequently, no further description of such mechanisms at this point is necessary. The ring 1 carrying the barking tools may be adjusted by actuation of the cylinder 13 to center the ring with logs of various size, and the sequence of feeding the log, engaging it successively with the hold-down devices and releasing the holddown devices from the log will be the same as described already.

In Figures 7 and 8 log feed mechanism is illustrated which utilizes the same type of hold-down devices described in conjunction with Figures 4, 9 and 10, and again may be used with a rotary ring barking machine, as already described. This feed mechanism, however, diifers in the log carrying apparatus. Here the log carrier includes a set of infeed rolls and charge rolls, which are shown somewhat diagrammatically in Figures 7 and 8. The infeed rolls set a series of idler rolls 6 at locations remote from the barking machine, and a series of powered rolls 60 close to the barking machine. Such powered rolls may be interconnected by drive chains 61 which are driven by the motor 62. through chains 63. Any convenient number of idler and powered rolls may be used.

Similarly, on the discharge side of the barking machine a series of powered rolls 64 is located adjacent to the barking machine, which are interconnected by chains 65 and driven by motor 66 through chain 67. Beyond the rolls 64 in the direction of log movement are idler rolls 68 on which the log will be supported when discharged from the live rolls 64. From these idler rolls a log may be lifted by swinging arms 7, which are carried by a shaft 70 oscillatable by a uid cylinder actuator 71. By swinging the arms upward logs may be pushed from the rolls 68 whereupon they will roll down the arms 7 onto ways 72 for further processing.

The shape of typical rolls which may be used as the live rolls can vary, but representative shapes are illustrated in Figures 11 to 14. Again, in order to prevent the log from being turned about its longitudinal axis, the log lcarrier and the hold-downs should cooperate to grip the periphery of the log firmly. Preferably a live roll is located under the rotary heads of each hold-down device, and such rolls may have the configuration shown in Figures ll and l2, being made of two frusto-conical sections 8. Each section has on its periphery annular ridges which have notches 81 at intervals to increase the tractive elort longitudinally of the log. The sharpened annular ridges, like the ridges 55 of the hold-down wheels 51, will dig into the log periphery to resist rotation of the log. The two conical roll segments are mounted with their smaller ends in abutment on a shaft 82.

Carrier rolls which are not located directly under holddown heads would not be particularly effective in resisting rotation of a log. It is desirable, however, that they produce maximum tractive force to feed the log endwise. For such rolls, therefore, the configuration shown in Figures 13 and 14 may be employed. Again, these rolls preferably are composed of two frusto-conical sections 83 mounted with their smaller ends in abutment on a shaft 84. Traction ribs S5 are formed on each of these sections extending longitudinally of them. The idler rolls, of course, merely support the log, and consequently need not have any ribs.

Since the hold-down devices and their operation have been discussed previously, it will be evident how they are manipulated during feeding of a log -by the roll type carrier described, so that no further description of this embodirnent of the log feed apparatus is necessary.

In Figures 15 and 16 an alternative type of supporting structure for rotary hold-down heads is illustrated, which,

a set of dismay include ofl-eoursef'maybe-n'tilized 'with any yof-the log carrier-arrangementsdis'cussedabove. In this instance the rotary hold-down -lheadsare shown-as Vineorp orating several; annular ribs'taperedin the 'group yaway from "the supporting arms 9, likethoseioffFigures l,2:-an1d"3. These rotary heads-arejournaled on'aXl'es extending substantially 'parallelto-tangents tothe legi-at' the locations of rotaryy head contactf'with the logs' r`as in the YIMhold-'down 'devices' `previously described. Thisfhold-down mechanism `dillers, however,-intthe-rnanner `in-which the axles are supported. Only one' pairf'f: hold-down "devices is illustrated" in Figure 15 but it will -be understood that any number of pairs may I'bei utilized, larran'ged-fle'ngthwise of the "loge-carrier comparable to the ffarrangementof "hold-down. devices shownin Figures 1,' Atranci-57; foreexample.

r-'I`helog-carrier with which thelholddown'devices cooperate incorporates flights 40"` generallyv comparable to theights G4015i theflogicarriermechansm shown in Figures 4,?eandf6jbuthaving assingle centrall projection 41' located` centrally of the llights lower edge to which a singledi-ve 'chain`4 is'secured. "Shoes45j on the lower cornersof''theflights"40"ride"onsupporting tracks such as theangle-members"44. The chain't`4' will, of course, be of -theendless type andwllbe'attached to log supporting ightsilwatintervals suitableto enable such flights tosupportffa log f' properly 'in a position centrally between the hold-down supports.

' The rotary hold-downN` heads 'S"y are mounted on axles carried by 'i arms v49, which -'arms are mounted on wheeled carriages j90. Such4 carriages maybe of generally re'ctangular shape-and have'awheel `jpournaledateach corner to rotateab'outan axis transversely ofjtlierotative'a'xe'sof hold-down Aheads'l'rarld extending)generallyparallel to a log Lon the ylog carrier. As shown in'Figure 1'6, vthe wheelsl on'opposite sides "of the carriages 90-"are .received infarcu-ate channel tracks`91. lnFigure l5 thetra'cks on the'nearside of the view have'been'broken awaytoreveal the carriage structure. These 'tiacks are supported by suitable posts 92 supported on beams'93.

The curvature ofthe 'tracks 91 and their angularity relative to rbeams 93 will tbe -such that tracks on the opposite sides of-the `log carrier converge downward. Asthe carriages 90 are moved upward'along such tracks, therefore, the spacing of the -rotaryhold-down.heads 3 will increase lat a rate progressivelygreater for equal incremental movements of the carriages. The spacing of.the'.tracks at opposite sides of the log carrier adjacent to theirlower vends -willbe sutliciently great to accommodate betweenlthe tracks a logof 4-the'wrnairimurn size desired to be processed by 'the log barking-machine. A medium sized logis illustrated as being engagedby the hold-downheads inFigure l5 and Vbrokenclines indicate a-smaller logand va log 4of substantially the 'maximum size lwhich couldY be handled by the mechanism. The positions which the hold-down devices would -occupy along lrails `91fforengaging the 'largest log indicated are illustrated in ybroken lines.

Movementof the carriages '90 yalong the tracks 91 is effected by uid piston and-'cylinder actuators 94 which are lpivotally connected toprojections `95 extending from the carriage opposite the extension of head supporting arms 9. The opposite'ends of such actuators are vpivotally -supported bypivots .96 carried by suitable stationary reactionstructure mounted on beams y93. As in the previous types of hold-down devices discussed, these actuators may be controlled jointly to move the holddown heads upward or downward simultaneously along tracks 91.A

The log feed mechanism incorporating the hold-down devices shown in Figures l5l and 16 can be operated in a manner similar Vto the Aother forms of Aapparatus discussed above.

I claim asmy invention:

l. [Log vfeed mechanism comprising carrier means mon "axis/extending transversely of v`the direction 4of movement Yof said Ycarrier means, and' means connected to each olf-said `lever arms between its pivot andits disks and operable to exert Va `force 'on said lever arms in a direction to` move said diskstoward said carrier means and press the'edges of said disks against upper portions of a 'log on said' carrier meansewhichV are spaced transversely of the log 'to'deter rotatiton of the log and to press the log downward against said carrier means.

2."Mechanism comprising carrier means operable to support and to advance a log longitudinally and including chain'ftr'a'nsport means advancing with the log and operablewhen a log is pressed thereagainst ltoY resist rotation of a log about its axis, andanti-rotation holddown. means including two lever arms disposed -one at each side of .said carrier means, apivot supporting one end of ea'ch ofsaid lever 'arrns'remote from said carrier means, a head including several rotative yaxially spaced annular 'log-engaging ribs 'mounted -on the swinging other end of each of said lever arms and rotativefabo'ut an axis extending transversely of'thedirection of movement of said carrier means, and fluid .pressure operated means connected'to each of said lever-arms between its pivot and 'its head and operable toexert a force on said lever arms in a'direction to move said heads toward said carrier means and presssaid ribs against upper portions of a log on 'said carrier-means which are spaced transversely of the log to'deter rotation of the log and to press the-log downward against said. carrier means.

3. Log feed mechanism comprising carrier means operable ito support and to advance a log longitudinally, and anti-rotation hold-down means including two lever arms disposed one at Veach side of said carrier means directly opposite transversely of the direction of movement of such means, two pivot means disposed substantially level with'said carrier means at opposite sides of said carrier means, each pivot means delining an axis extending substantially parallel to the direction of log advance effected by said carrier means and supporting one of said lever arms inclined upwardly toward said carrier means for swinging relative thereto, arotary head incorporating several rotative axially-spacedannular log-engaginglribs carried-by the-swinging end ofeach of said lever arms and rotativel about the same'aXis extending transversely of-'the direction of advance of the log, rand 'means operable to swing `said lever arms to move said heads toward said carrier,meansintopositions engaging the upper portion of ailoig on, saidecarrier means which are spacedtransverselyof the log an'd located at opposite'sides of the vertic'al-diametralplane vof the log for restraining rotation ofthelog.

4. Log feed mechanisnrcomprising carrier Ameans operable to support'and to advance a Vlog longitudinally and including chain transport means advancing with the log andoperable when-alog is pressed thereagainst to resist rotation 'of .'suchalog 1aboutits axis, and anti-rotation hold-down:'means'fincluding two anns disposed one at each 'side of said carrier means, a head including several rotativeairially'spac'ed annularlog-engaging ribs mounted oneacl1 of saidarmsand rotative about'the same axis extending-transversely `of-the direction of movement 'of said carrier meansymea'ns Ysupporting said arms for movement to move saidheads .toward and away Ifrom said l carrier means, and means connected to each of said arms and exerting a force thereon in a direction to move said heads toward said carrier means and press said ribs against upper portions of a log on said carrier means which are spaced transversely of the log to deter rotation of the log and to press the log downward against said carrier means.

5. Log feed mechanism comprising carrier means operable to support and to advance a log longitudinally and operable when a log is pressed thereagainst to resist rotation of a log about its axis, and anti-rotation hold-down means including two heads spaced transversely of the log and located at opposite sides of the vertical diametral plane of the log, each head including several rotative axially spaced annular log-engaging ribs rotative about the same 'axis extending transversely of the direction of movement of said carrier means, means supporting said heads for movement toward and away from said carrier means, and means connected to said supporting means and exerting a force thereon in a direction to move said heads toward said carrier means and press said ribs against upper portions of a log on said carrier means which are spaced transversely of the log to deter rotation of the log and to press the log downward against said carrier means.

6. The log feed mechanism defined in claim 5, in which the means supporting the heads for movement toward and away from the carrier means includes two tracks disposed one at each side of the carrier means in generally upright position but convergent downwardly, and carriages guided for movement along said tracks, respectively, on which the heads are mounted, and the means connected to the supporting means and exerting a force thereon in a direction to move the heads toward the carrier means includes means operable to move said carriages toward the carrier means.

7. The log feed mechanism defined in claim 5, in which the carrier means includes log-supporting gripping plate ight means disposed in an upright plane and having loggripping projections on its upper edge operable when a log is pressed thereagainst to resist rotation of the log about its axis.

8. 'I'he log feed mechanism defined in claim 5, in which the cartier means includes endless chain means, a plurality of log-supporting members spaced lengthwise of said chain means and secured thereto at intervals, respectively, for movement thereby, 'and two rails parallel to each other and to the length of said chain means, spaced farther apart than the width of said chain means and disposed with said chain means therebetween, said rails being engageable by said log-supporting members to support the log-supporting members by said rails.

9. The log feed mechanism defined in claim 5, in which the carrier means includes a chain movable lengthwise of the direction of log advance, a plurality of spaced logsupporting gripping flights secured to said chain at intervals, respectively, and operable to support a log thereon and to resist rotation of the log about its axis when pressed thereagainst, and spaced rails disposed transversely of said ights and engageable by said ights to support the same, said ights having means projecting downwardly therefrom and engaging said rails to limit shifting of said ights transversely of said rails.

References Cited in the tile of this patent UNITED STATES PATENTS 358,550 Harvey Mar. 1, 1887 445,123 McKnight Jan. 20, 1891 482,319 Rodgers Sept. 6, 1892 518,031 Garland Apr. 10, 1894 547,432 Hauser Oct. 8, 1895 549,575 Linn et al Nov. 12, 1895 672,498 Tothill Apr. 23, 1901 799,836 Dittbenner Sept. 19, 1905 877,878 Anderson Jan. 28, 1908 900,677 Mereen et a1. Oct. 6, 1908 940,016 I-Iick Nov. 16, 1909 1,180,676 Snyder Apr. 25, 1916 1,252,894 Fitzgerald Jan. 8, 1918 1,773,476 Chamberlain Aug. 18, 1930 1,938,108 Morris Dec. 5, 1933 2,125,919 Harris Aug. 9, 1938 2,209,257 Blank July 23, 1940 2,266,506 Morse Dec. 16, 1941 2,448,689 Schnyder Sept. 7, 1948 2,591,751 Whitlock Apr. 8, 1952 FOREIGN PATENTS 123,578 Germany Sept. 25, 1901 29,514 Sweden Sept. 17, 1910 34,951 Sweden June 4, 1913 115,238 Sweden Oct. 23, 1945