US2687152A - Hydraulic log-barking apparatus having opposed slit-nozzles and log-aligning conveyers - Google Patents

Description

Aug. 24, 1954 I s, HANSEL 2,687,152 HYDRAULIC L BARKING APPARATUS HAVING OPPOSED SLIT-NO ES AND LOG-ALIGNIN 51 G CONVEYERS Filed Nov. '15, 19 3 Sheets-Sheet l Inventor {y -hey a'iweZ W fiww Attomeys Aug. 24, 1954 s. HANSEL -BARKING APPARATUS HAVING OPPOSED 2,687,152 HYDRAULIC LOG SLIT-NOZZLES AND LOG-ALIGNING CONVEYERS 3 Sheets-Sheet 2 Filed NOV. 15, 1951 0 s a m ii. I lllll l ll lll II 1 Inventor yczwey #572862 2 I P Ailomeya Aug. 24, 1954 s. HANSEL 2,587,152 HYDRAULIC LOG-BARKING APPARATUS HAVING OPPOSED SLIT-NOZZLES AND LOG-ALIGNING CONVEYERS Filed Nov. 15, 1951 3 Sheets-Sheet 3 a a a a a v a a n q o 4 n a a a q o c o 4 Inventor Jycl vey /gnoe Z y E 2 Z r Attorney Patented Aug. 24, 1954 HYDRAULIC LOG-BARKING APPARATUS HAVING OPPOSED SLIT-NOZZLES AND LOG-ALIGNING CONVEYERS Sydney Hansel, Vancouver, British Columbia,

. Canada Application November 15, 1951, Serial No. 256,537

This invention relates to the removal of bark from logs, sticks, slabs or edging by subjecting them to the action of Water at high pressure.

One object of the invention is to provide a novel means by which the bark is progressively removed from the logs over their entire circumference.

Another object of the invention is to provide a log barking apparatus in which barking is effected by a progressive peeling action produced by high pressure liquid jets.

A further object resides in the provision of a log barking apparatus capable of individually or simultaneously handling logs of different diameters or lengths without the necessity for any adjustments.

Still another object is to avoid displacement of the logs to prevent their escaping from the action of the liquid jets.

Another object resides in the provision of means for dressingthe logs and feeding them to the barking position so that they are favorably located in relation to the liquid jets.

Other objects and advantages of the invention will be evident from the following detailed description of some embodiments thereofand of the drawings illustrating said embodiments. In said drawings:

Figure 1A and 1B jointly show one apparatus in perspective diagram;

Figure 2 is a longitudinal sectional view showing details of the barking unit;

Figure 3 is a transverse section on line III-III of Figure 2;

Figure 4 shows a modification of the barking conveyor;

Figure 5 is a detail perspective view illustrating the bark disposal features of the apparatus of Figure 1A;

Figure 6 is a longitudinal view showing diagrammatically a modification of the log barking device; and

Figure '7 is an end view of Figure 6' as seen in the direction of arrow VII.

The removal of the bark from logs by means of one or more jets of water at high pressure directed against the surfaces of the logs is well known but difiiculties have resulted from such system which have been used commercially, among the more important of which are the entire removal of the bark from each log in a single operation; the tendency particularly of the smaller size logs to, be deflected by and escape from the action of the water jets; the very substantial space occupied by the plant; and the efiicientjdressing of the logs and feeding to the 19 Claims. (01. 144-208) barking station. These difficulties have resulted in the need for considerable man-power at each plant and in an uneconomical rate of production of clean barked logs.

The present invention provides an improved or novel method and apparatus which eliminates or substantially reduces these difliculties. It allows for the treatment of a number of logs simultaneously and the dressing and feeding of the logs in batches to the barking station. It also ensures that the logs will be barked over their entire area during a single pass and that they cannot escape from the water action.

The apparatus employed in the barking of logs according to the embodiment of the invention illustrated in Figure 1 comprises a barking unit A through which the logs are moved progressively in batches and subjected to the action of slit jets of water impinging against the entire bark surface of each log a dressing unit B in which the s to be barked are dressed and arranged so that they arrive at the output end of said unit in an end-on condition and are spaced so that they can be handled individually; and a transfer unit C in which the logs are batched and by which they are conveyed to the barking unit.

The barking unit is shown as including a conveyor consisting of a pair of laterally spaced endles chains Ill supported by pairs of sprocket wheels I I, I2 mounted at opposite ends of a frame l3 on shafts l4, l5 respectively which are jourthe logs are moved during the barking operation,

said table being supported above the frame I3 by pillars 20. The table has fixed or integral therewith a hood 2| of inverted U-shaped crossection which forms with the table an open-ended chamber through which the logs are arranged to pass and in which the barking operation is carried out. The barking conveyor is driven from an electric motor 22 by a belt and pulley or-equivalent drive 23 and an intermediate shaft W to the shaft I4.

Barking of the logs is effected as they pass through the chamber formed by the hood 2| by plied from a pump 24 driven by an electric motor 25 and passes through a conduit 2% which is branched at 2?, 21' to a pair of nozzle housings 28, 28. These nozzle housings are arranged transversely of the conveyor, the upper housing registering with an opening 29 inthe hood 2! and the lower housing registering With an opening 30 (Figure-,2) in the table l9, so that jets of water can be projected both downwardly and upwardly against the log as they pass through the barking;

chamber. The housings are each formed with a slit nozzle 3| or 31 having alength,, as shown in Figure 3, corresponding to the width ofthe conveyor compartments, so that the jets of water from the upper housing impinge; against th'ezenrtire upper surface portions of the logs while those from the lower housing impinge against the entire lower surface portions of the logs.

The logs a: to be barked are arrangedin the conveyor compartments so that they lie lengthwise-of. theconveyor, the jet-:actionthus being;

applied so as-to commenceatone end of .the logs and; to pass along themvas they are movedthrough the barking chamber. Further, in order that the entire surface-of. each logshall-be subjected to the jet action it is important that the logs in'theconveyor, compartments shall be placed :therein so that theylieside by side and-not ontop of one another.- For this reasononly sufficient logs;

arev placed in each conveyor compartment as to form a single layer. barking chamber formed by thehood 2| is such as to provide for the passage-bf logs of a. predetermined maximum diameter and means are'providedinfront of theforwardend of the barkingchamber to prevent the admission thereto of oversize diameter logs which might damage I the conveyor or water jet mechanism. Such" means; in the embodiment illustrated, comprises a switch controlling the circuit of, the conveyor driving motorand mounted on an upstanding support 34 straddling. the conveyor. Theswitch consists; ofv

a hinged platese .which carriesan, insulated contact. 3t v engageable with 'asecond insulated, contact S'Lmountedonv a plate -38 fixed to the sup: port 34,. said hinged plate being normally positioned,.as shown, in Figure-2, soas-ta be engaged by the leading end of an oversize diameter log,

or a-v superposed log, and thus rockedto-closethe:

contacts, 36,371.. This closing of the contacts :is arranged to. break the-circuit or" motor22 in any convenient, or known manner and is not shown in the drawings. switch and provide sufficient time lag-for the stopping ofthe conveyor, the contact 31 maybe flexibly mountedso that it will be pressed rear.- wardly by the plate .under the action of an advancing log and will return to its normal. posi-:

tion once said log has been removed from the 1 conveyor.

The table 19 is perforated as at 40 (Figure 2):

at ,least along that portion ofits length which forms the base of the barking chamber so as :to.

allow for escape of thebarking water. The barked and cleaned logs are carried tonthe dise charge end of the barking conveyor wherethey" Some of the bark. removed from the logs, more especially; the smaller pieces, fall. through the-openingrw'iinr the table [9 and are collected by an endless.1trans-:--

aretransferred to a chute 4|.

verse conveyor 42, (see Figures 2 and 5) the upper run of which moves within a fixed trough shaped; guide 43' extending from one side of. the-framel3. The remainder of the bark travels. with the. logs to the discharge end of, the conveyor; from;

Moreover, theheightof: the

To prevent damageto. the

whence it falls on to a second endless transverse conveyor 44 having its upper run moving within a fixed trough shaped guide 45 extending from the same side of the frame l3 as the guide 43. The conveyors 42, 44 discharge the bark to an endless conveyor 48 extending parallel to the barking conveyorand mounted on rollers 41 journalled in pairs. ofzbearings 48 ataopposite ends of aframe 49, the bark being removed from conveyor 46 for disposal in any convenient manner.

to flanges 53 ontube portions .54 extending irom the nozzlechousi-ngs; Either or both flanges 5 l, 53

of each pair may; beprovidedwithansannula-r series of bolt holes spaced so as to permitangular.

adjustment of the flange 53..with relationtothev flange 5|. Figurexzshows in fullandchairrlines the two. housingseadjusted'to direct-the water, jets. towardsgthe forward ends. ofv the advancing" logs at diirerent angles to thgplane-of the-con.

veyor. This, angular adjustment of the nozzle housings is ot considerable importancein they efficient barking of,thelogszsince inxtheir angu lar positions the Jets produce a; peeling action.-: on the bark so as to prize the latter from thelogsn in theform of :moreor. less lcngstrips. Thevjet angle can thus be ,varied either;v according ;to-; the .1 species of wood under treatment onto the bark-e ing propensities of the wood, which vary-according to the season of the year.

The transverse plates lfljof the/barking conveyor are shown in, Figures 1 ands-2 as: beingpfiat.

and arranged perpendicular :to the-conveyor;run.

However; in order to :permit the water jets :to bee directed. againstthe forwardendsof the advance ing logsas the latter approach the-nozzle hous ings, said plates [8 may preferably boot-angular;

or V.-shape as shown atpl8 in Figure 4, with: the

apex facing the opposite direction' 'to. that-of..:the.;

travel of the conveyor.

The treatment of the-logs:on therbarkingmone veyor as described .above-requiresthat gtheyrshall be located lengthwise on said conveyorrwitl rre-zspect-totheir-direction ofrtravel. In commercial barking practice the logs may be broughtrtothe barking positioniromra storage. or assembly position by suitable, conveying means rand-i then.

present invention envisages the use of z suchzcona veying means by 1 which :the: logs are; dressed .-i so thatthey are in an .end-on; position in: relation to the barking conveyor. conyeyingmeans. provides for batching. {or group.-

ing of the logs correspondinggtoi-the capacityrofa.

the. barking conveyor compartments;rformedzzbetween..,th'e chains. Wand plates' 58.x. Such ;con-'-;-

veyingmeans, which will now be' described;- come. prises the dressing unitB and;transferrunit .G. previously mentioned.

The. dressingxunit B. which is ,showng'in Fig? ures ,lA and 1B, as lying parallelto :the barkingt: unitA-and is arranged toone side rthereofzwitht its leading or deliveryend slightly in advance =ofr the rear end of the barking=;conv.eyor,v comprises a frame :60 supporting at itsz'rear endiarr endless conveyor band.- 6 l on :;to whichizthe elogs to Preferably ,ELISO'Z such;

be barked are delivered as by means of a chute B2. The conveyor is carried on rollers 63, 64 having their axes journalled in bearings 65, 66 on the frame 60. The logs come to rest on the conveyor band in jumbled or haphazard positions and before leaving said conveyor they pass through a spacing gate 61 which locates them in more or less predetermined paths lengthwise of said conveyor and also in more or less end-on positions, while, at the same time holding back those logs which are lying on other logs. The gate comprises a pair of upright side posts formed as extensions of the bearings 66 at the forward end of the conveyor in which is supported a vertically adjustable transverse beam 68 carrying a plurality of depending bars or springs 69. Since the bars are spaced apart bya distance greater than the maximum diameter of the logs, the latter, especially the smaller diameter logs, although being positioned by the bars inmore or less predetermined longitudinal paths, may not be accurately aligned on the conveyor when they leave the gate. Such longitudinal alignment of the logs is thereafter effected by a series of transverse rollers over which the logs are caused to pass after leaving the conveyor 6!. These aligning rollers, four of which are illustrated at E0, 11,12 and 13 respectively, are journalled in bearing blocks M mounted on the frame 69 immediately beyond the forward end of the conveyor 6|. The rollers are of equal diameter and are arranged with their axes in a common horizontal plane. They are, however, each rotated at a speed greater than that of the preceding roller i. e., roller ll turns faster than roller 19, roller 12 turns faster than roller H, and roller 13 turns faster than roller (2. Roller 19 may be rotated so that its surface speed is greater than that of conveyor 6!. The conveyor 6i and the rollers -13 are driven from an electric motor 75 through a belt and pulley or equivalent drive 16 including a nest of driving pulleys H of progressively increasing diameter, the smallest driving the roller 64 of the conveyor and the others driving the rollers ill-13. The logs, after leaving the rollers, pass on to a further endless conveyor 18 passing about rollers 19, 80 having their axes journalled in pairs of bearings 8!, 82

on the frame 60 and said conveyor may be driven from the nest of pulleys 11 by a belt and pulley or equivalent drive 83 either at the surface speed of the roller 13 or at a rather higher speed than said roller. In addition to the straightening effect applied to the logs the rollers HI-I3 also serve to space the logs lengthwise of the conveyor 18 so that they can be individually in spected for size or any other requirement before being passed to the barking conveyor and unsuitable logs removed. This longitudinal spacing of the logs is assisted by the action of the gate 61, which prevents too many logs from passing on to the rollers 10-13 simultaneously.

The frame 60 is formed at its forward end with an extension 85 arranged at right-angles thereto and terminating adjacent the barking unit A rearwardly of the switch support 34. This extension frame carries bearings 86 in which is journalled one of a pair of rollers 81, 88 the other of which is journalled in bearings 89 (only one of which is shown) at the adjacent side of the barking unit frame [3. These two rollers 81, 88 support an endless transfer conveyor belt 90 driven from an electric motor 9| through a belt and pulley or equivalent drive 92 and which at intervals along its length is, provided with transverse upstanding plates 93. The spacing of the plates 93 is approximately equal to the width of the barking conveyor between the chains [5. One edge of the conveyor is located adjacent the delivery end of the conveyor 18 so that the logs leaving said latter conveyor pass on to the conveyor 99. The transferconveyor 90 is driven at a speed such that each compartment thereon formed between a pair of successive plates 93 Will be substantially filled with logs from the conveyor 18 while said compartment travels across the end of said conveyor. It is important therefore that the supply of logs from the conveyor 58 shall not bein excess of the capacity of the transfer conveyor and the motor '5 driving the belt GI and rollers 10-13 is conveniently fitted with a gear box 15' by whichthe speeds of said belt and rollers can be controlled. The barking conveyor also is driven in synchronism with the transfer conveyor 90 so that the logs in each compartment on the transfer conveyor are offloaded on to the barking conveyor While one compartment on the latter conveyor travels across the end of the transfer conveyor, said compartments each being of a length in excess of the width of the transfer conveyor so as to enable this operation to be effected without stopping the barking conveyor. Off-loading of the logs from the transfer conveyor directly into the compartments of the barking conveyor is achieved by locating the discharge end of the transfer conveyor above the upper run of the barking conveyor. The transfer unit is fitted with fixed guides 94, at opposite sides of the upper run of the conveyor 90, the guide 94 aligningthe forward ends of the logs passing on to the conveyor 90 from the conveyor 18 and the guide 95 being cut away adjacent the conveyor 18 to permit the logs to pass on to the transfer conveyor. The guides 94, 95 are carried by brackets 96 secured to the extension frame 85.

From the foregoing it will be evident that, provided suitable speeds are chosen for the several conveyors and rollers, the apparatus will function to dress, batch and completely bark. the logs in a single operation and in a substantially automatic manner with a minimum of supervision. Apart from an operator at the input end of the batching or transfer unit C (who may also inspect the logs approaching the delivery end of conveyor 18 and remove unsuitable logs by rolling them laterally off said conveyor) and an operator at the gate 61 to ensure that the logs are passed through at the maximum rate consistent with the capacity of the transfer and barking units, no further man-power need be required. In the United States of America and Canada the pulpwood logs for which the apparatus of Figure l is particularly, though not exclusively, designed are generally of a length of between four and eight feet and a diameter of between two and twenty inches, and such logs can be rolled quite easily by a single operator on the conveyors BI and 18.

The foregoing detailed description refers particularly to the barking of logs, by which is understood lengths of timber having bark-covered cylindrical surfaces. The apparatus may also be arranged to bark sawed lengths such as slabs and edgings which are only partly surfaced with bark. In such cases the slabs or edgings, which can quite easily be filled manually into the bark ing compartments without using the dressing and transfer units, are arranged with their bark surfaces uppermost. This requires only the use of thew-upper nozzl'e housing 28 170i supply the barking water and the'branch' conduit 2 I'- is fitted with a cock 2]. 'enablingthe water supply to the lower nozzle housing 28 to becut off.

When the unbarked'logs are being batched an operator may be required to checkthe loadingends restingon the plates I8the"switch plate 35' may be spring-loaded so that saidlogs'are pushed off the plates=l8 as theconveyor advances, the switch circuit being closed only if plate 35 should be engaged by anoversizelog whose rear end is abutted bythe-following plate I8. During the actual barking operation the hood 2] prevents the possibility of'the logs' becoming displaced or superposed on-one another under the action of the high pressure-water jets and also protectsany operator in the vicinity from the effects of the water;

while itis more usual in the United States of America-and Canada 'to cut-pulpwoodilogs to the relatively short lengths mentioned above; the method of barking bymeans of'transverse slit jets of water which impingeon opposite sides of the logs is equally applicable to much longer logs which, particularly in Sweden and Finland, may have a length of up to 26- feet.

ticularly in regard to the handling of logs in batches. It-is therefore preferred to use-in such cases the apparatus diagrammatically illustrated in Figures 6 and 7, which is-designed for operating on the logs one at a-time.

The apparatus-shown in these figures comprises a rear perforated table IOI and a-forward perforated table-I 92; said tables being longitudinally aligned and" appropriately spaced between their adj-'ac'ent ends to' permit the j ets ofwaterfrom the upperiand lower nozzle: housings I 03; I M to impinge against -the logs :c as-the latter are ad. vanced'through th'e apparatus E'ach table supportstheraupperrun o-fi one of 'aipair of-endless, chainlconveyor belts I 85; I it-passing about end rollers. IO'I'Zand IIlB respectiVely which are journailedin'the'machine-frame (not shown), said belts being driven in any convenient manner at equalospeeds. Each belt is provided throughout its lengthwith upstanding pinsystuds or the like I09 arranged in transverse rows which engage the logs and'thus' convey them throughth'e apparatusandthis "grippingeffect of the belts on thelogs is assisted bya series of studdedbrlik'e endlesstbel-ts"arrangedabove each conveyor belt. In .the'arrangement'showneach' of said series comprises." a .centrezbelt I I I I] or I I I and two side belts I II) or I I I', the centre belt engaging against the uppermostrsurfa'ce. portion of each" logand the-side beltsiengagingndjacent side surface portions; as; will-.be1clearfrom .Figure '7 The belts 1 Hi1, III) areisupported each on a' pair of freely rotatable rollersiil I221 I2; the rollers II2-'being coaxially; journ'alled" in: the machine frame and.:.the;-?'r011rsII2 being journalled in supporting: arms:. I I3 I- mounted r" for pivotal movements. on the; common: axis: of the rollers I I21 The-sbeltsrl I: I I I I: areireachzsimilarly supported onza pair of'rfreelyzrotatable rollers 1 I4; --I I4-', the

The apparatus describedwith reference to Figures 1 to 5is, however, unsuitablefor these larger logs, par-- latter: beingjournalled in supporting arms -I I5? The pairs ofarms carrying the rollers H2 and I I4 may be arrangedso that each series oflbelts III), III) or III, III is urged gravitationally to engage the logs; or saidpairs of arms may be resiliently loaded for this purpose. Under the pressure exerted on them by these series of belts the logs are maintained in contact with the conveyor belts I95, Illii'and are prevented from beingcauseclto slide over said belts due to the high.

pressure water jets. As will be seen from Figure 6, the two seriesof upper belts are located above the adjacent ends of'the conveyor belts andthus operate to hold the logs steady'while they-are passing across the water jet-zone between-the- Additional supporting rollers H6, 1'

two belts. for thelogs may be providedbetween the belts. The tables are shownprovided with side guides H8, I It respectively.

By reason of the greater'length. of log which the apparatus ofFiguresfi-and '7 "is capableof handling, the spacing between the two conveyor belts Hi5; iflli may be considerablygreater than the openings 29, 3Q in'the apparatus of Figures 1 to 5. Most, if not all of the removed'barkwill therefore discharge through the space between saidbelts and it may in general be necessaryto employ only the one transverse bark disposal conveyor IZll beneath said space instead of the two conveyors r12, ld of-theearlier embodiment. In addition to' the peeling action produced on the bark by the slit jets, other nozzles I2I, I22-may be provided above and'below the path of travel of the logs andin advance of the nozzle housings 193; I841 (considered in relation to the travel of the logs) to cutor breakdown the bark'before it is finally removed by the slit jets. These nozzles I 2 3, W2 arethus preferably arranged to provide water jets which are substantially perpendicular to the travel of the logs and are of particu-- lar'advantage in thecase of cedar logs,where the bark, although quite easy to-remove; is of a fibrous nature and tends to clog" the conveyors. Thus dueto the cuttingaction produced by-the waterjets from the nozzles I23, lfifi'th'e bark peeled from" the logs will come away in shortpieces and will collected and removed by the conveyor I 20'.

The nozzles lZl, i22'are fitted with means (notshown) forturningthem on and off as required.

As in the earlier embodiment,- th'e'nozzlehousings M23, IM- are preferably constructed to allow for adjustment of-the jet angle, and a hood may be provided to enclose the jetzone -and possibly also the upper series-of'belts H0, Iiil and III, EH at Bin Figure lB'may' be'employed to feed the logs one at a time and in end-on disposition to the bark-ing-conveyor-IGE but the batching and trans-- fer device C of the earlierembodiment will not be required."

While in the preceding description reference which the logs are progressively advanced longitudinally, a pair of housings arranged one at either side of the path of travel of the logs, means supplying water at high pressure to'said'housings; and a slit nozzle in that side of 'eachhousing facing said path of travel, said slit nozzl'esextending transversely of thedirection of log travel and'be- I ing'of a length not less than the-log width.

An aligning devicesi-milar to that 'shown' 2. Log barking apparatus as claimed in claim 1 whereinthe slit nozzles are disposed so as to direct the water jets in an inclined direction "counter to that of the log feed.

3. Log barking apparatus comprising a conveyor for the logs, means for driving said conveyor to advance the logs lengthwise, a pair of nozzle housings arranged respectively above and below said conveyor and extending transversely in relation to the conveyor feed, and means sup plying liquid at high pressure to said nozzle housings, the latter each having at that side facing the conveyor a slit nozzle extending transversely of the direction of feed of the conveyor and having a length not substantially less than the log width.

4. Log barking apparatus as claimed in claim 3, wherein the logs are advanced singly between the nozzle housings.

5. Log barking apparatus as claimed in claim 3,

wherein the logs are arranged side by side in a single layer on the conveyor.

6. Log barking apparatus comprising a pair of spaced conveyor chains and plates secured transversely at intervals between said chains so as to form therewith a series of conveyor compartments in which the logs are arranged lengthwise of the conveyor, means for driving said conveyor, a barking chamber through which said conveyor passes, a pair of nozzle housings arranged respectively above and below said chamber and extending transversely in relation to the conveyor, openings in the walls of said chamber opposite said nozzle housings, and means supplying liquid at high pressure to the nozzle housings, the latter each having at that side facing the conveyor a slit nozzle extending transversely of the direction of feed of the conveyor and having a length approximately equal to the full log width.

7. Log barking apparatus as claimed in claim 6, wherein each nozzle housing is angularly adjustable about an axis transversely of the conveyor.

8. Log barking apparatus as claimed in claim 6, wherein each nozzle housing is formed with a slit nozzle extending over the full width of the conveyor.

9. Log barking apparatus as claimed in claim 6, wherein the barking chamber comprises a rectangular open-ended casing having transverse openings in its flat upper and lower walls registering with the nozzle housings, the said lower wall forming a perforated table supporting the logs and along which the conveyor moves.

10. Log barking apparatus as claimed in claim 6, wherein the barking chamber comprises a rectangular open-ended casing having transverse openings in its fiat upper and lower walls registering with the nozzle housings, the said lower wall extending longitudinally beyond the casing to form a log-supporting table along which the conveyor travels and being perforated at least along that portion corresponding to the barking chamber.

11. Log barking apparatus comprising a conveyor on which the logs are placed in a single layer, means for driving said conveyor to advance the logs lengthwise, a fixed open-ended casing through which the conveyor travels, means for supplying transverse slit streams of liquid both upwardly and downwardly into said casing so as to impinge against the bark surfaces of the logs over the full log width, and means in advance of the casing for automatically interrupting the conveyor drive in the event that the diameter of a log on the conveyor exceeds the height of the casing.

12. Log barking apparatus as claimed in claim 11, wherein the conveyor is driven by an electric motor the circuit of which is controlled by a switch mounted above the conveyor in advance of the casing and having a movable element located at a height not substantially less than the internal height of said casing.

13. Log barking apparatus comprising a conveyor on which the logs are arranged lengthwise, means for driving said conveyor, means for directing two transverse slit jets of liquid in opposed directions against the bark surfaces of the logs over their full width, and mechanical means for aligning the logs with said conveyor prior to their transfer thereto.

14. Log barking apparatus comprising a compartmented conveyor on which the logs are placed lengthwise in a single layer, means for driving said conveyor, means for directing two transverse slit jets of liquid in opposed directions against the bark surfaces of the logs over the full log width, mechanical means for aligning the logs with said conveyor prior to their transfer thereto, and means for batching the aligned logs and placing said batches in successive conveyor compart ments. 1

15. Log barking apparatus comprising a conveyor on which the logs are placed lengthwise, means for driving said conveyor, means for directing two transverse slit jets of liquid in opposed directions against the bark surfaces of the logs over their full width, a row of transversely arranged rollers towards which the logs are fed prior to being placed on said conveyor, means for driving successive rollers at speeds higher than that of the immediately preceding roller thereby to align the logs with said conveyor, and means for transferring the logs from said rollers to said conveyor. 1

16. Log barking apparatus comprising a compartmented conveyor on which the logs are placed lengthwise in a single layer, means for driving said conveyor, means for projecting two transverse slit jets of liquid in opposed directions against the bark surfaces of the logs over the full log width, a gate through which the logs are fed in an end-on direction so as to be segregated into a plurality of longitudinal rows, a row of transversely arranged rollers towards which the logs are moved from said gate, means for driving successive rollers at speeds greater than that of the immediately preceding roller thereby to align the logs with said conveyor, and means for batching the logs leaving said rollers and for transferring the batched logs to the compartments of said conveyor.

17. Log barking apparatus as claimed in claim 16, wherein the batching means for the logs comprises a continuously driven conveyor having upstanding transverse plates which form compartments to which the logs leaving the aligning rollers are delivered in end-0n positions to lie transversely of the batching conveyor, said latter conveyor being arranged transversely of the barking conveyor with its discharge end overlying said barking conveyor.

18. Log barking apparatus comprising two 1ongitudinally aligned conveyors on which the logs are progressively advanced in the direction of their length, a pair of nozzle housings extending transversely of the direction of feed of said conveyors and disposed intermediate their adjacent ends, and means supplying liquid at high pressure to said nozzle housings, the latter being provided with nozzles producing slit jets of liquid directed Numb er transversely andvin pposed, relation across;the

19.A.Log barking apparatus as claimed in claim ,18, wherein eachnozzle housing is angularly adjustable about an axis transversely of the con veyors.

" References Cited 1 in 'thejifile, .of this, patent UNITED :STATES 1 661356 Baker Marifi, 1-928 Number Number r 7 Name Date Swift Dec. 31,1946 :Holveck. et a1 Dec., 18,- 1951 Holveck et a1 .Feb. 26,1952 eGuettler Aug 5, 1-952 FOREIGN PATENTS Country Date Sweden Oct. '1, 1913

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