US1942095A

US1942095A - Wood barking machine

Info

Publication number: US1942095A
Application number: US535850A
Authority: US
Inventors: Gruber Joseph
Original assignee: INTERNAT WOOD AND SULPHITE CO
Current assignee: INTERNAT WOOD AND SULPHITE CO; INTERNATIONAL WOOD AND SULPHITE CO
Priority date: 1931-05-08
Filing date: 1931-05-08
Publication date: 1934-01-02
Anticipated expiration: 1951-01-02

Description

Jan. 2, 1934. GRUBER 1,942,095

woon BARKING MACHINE Filed May 8, 1931 5 Sheets-Sheet l FZZi IN VEN TOR BY fos 0/: Globe) A TTORNE Y Jan. 2, 19.34. J. GRUBER WOOD BARKING MACHINE Filed May 8, 1931 5 Sheets-Sheet 2 I N VEN TOR dZsep/z Gruber A TTORNE Y Jan. 2, 1934.

J. GRUBER WOOD BARKING MACHINE 5 Sheets-Sheet 3 INVENTOR a M W 6 m 0 ma Filed May 8, 1931 J. GRUBER WOOD BARKING MACHINE Jan. 2, 1934.

Filed May 8, 1931 5 Sheets-Sheet 4 INVENTOR vlzsepk Qwe/ ATTORNEY Jan. 2, 1934. J. GRUBER 1,942,095

WOOD BARKING MACHINE Filed May 8, 1931 5 Sheets-Sheet 5 I I /05 m5 m5 /5 J55 epk ruber ZQh ATTORNEY Patented Jan. 2, 193 1 parse stars tar ternationai Wood and Sulphite 00., Seattle,

Wash.

Application May 8, 1931. Serial No. 535,85ll

14 Ciaims.

This invention relates to barking machines of a form adapted for removing the bark from slabs of wood of irregular cross-sectional shape and the general objects of this invention are to provide a barkingmachine of this nature which is rapid and efiicient in operation and which is capable of feeding and barking slabs of uneven size and shape and which will operate efficiently irrespectiveof "the'thickness of the bark and which will remove all of the bark and leave the wood clean without removing and Wasting an excessive amount of wood.

In the manufacture of lumber from logs it is necessary to first square up the log an remove 15'the bark. This results in the production of a large amount of slab wood which is ordinarily burned or wasted. slab wood contains substantially all of the bark and also contains a large amount of solid wood. The solid wood is suitable for making wood pulp but the bark must first be removed therefrom as the bark can not be us'edforpulp purposes. The slabs are of various size and cross-sectional shape. Many of said slabs are fiat and plane on the sawed side and of the naturalrounded or segmental shape on the barkside. Others may be of substantially triangular shape and others may be of irregular shape and thinner at one end than at the other. The outer or bark surface will almost always be of rounded cross-section but the bark may vary greatly in thickness on different slabs and may even vary in thickness on the same slab and may be'very uneven, having bumps thereon or holes therein.

Znthe production of a successful and practice slab-barking machine it essential that eiiicient feed means he provided for supporting and feeding the slabs with the bark side uppermost whereby said bark side will be presented squarely to the rotary barking head by which aid bark is removed. It is also essential that this feedingmeans shall support and hold the slabs firmly so that their movement through the machine will 0 not'be eifected by engagement with the barking head said slabs being carried through at the proper speed to have all of the bark removed therefromf I accomplish this by providing a plurality of lower toothed feed rolls arranged in a plurality of parallel rows which rows are spaced a short distance apart to form lines of support on-which the slabs may rest and to leave clearance between rows of rolls for projecting portions of the slabs. This makes it possible to place slabs of substantially any cross-sectional (Cl. l m -208) shape on the feed rolls in such a position that the bark side of the slab will be directly uppermost.

It is also essential that the slabs be held down onto the lower feed rolls to insure proper feeding and to prevent them from jumping when theyfiQ-g encounter and leave the barking head. I accomplish this by providing upper driven feed rolls which rest on the slabs and help to feed said slabs through the machine. v

It is also essential to provide easily operated 5 and eiiicient gauging means under the control of the operator for gauging the depth of cut of the rotary barking head, which manually controlled] gauging means is supplemented by automatic positioning means which engages with and ism positioned by the top side of the slab which is being barked. I V

A further object of invention is to provide arotary barking knife which is shaped and constructed so that it will always tend to cut completely through the bark.

Other objects. are to provide a barking ma chine which is largely automatic in its operation. which is very easy to operate, and which is capa ble of barking slab wood very rapidly. 7

Other and more specific objects of the invention will be apparent from the following description taken in connection with the accompanying drawings.

The above mentioned general objects of my invention, together with others inherent in the same, are attained by the device illustrated in the following drawings, the same being preferred exemplary forms of embodiment of my invention, throughout which drawings like reference numerals indicate like parts: 7

Figure l is a plan View of a barking machine constructed in accordance with my invention.

Fig. 2 is a side elevation of this barking machine.

Fig. 3 is a front end elevation of the machine.

Fig. 4 is a somewhat diagrammatic plan view showing the feeding and driving mechanism with other parts omitted.

Fig. 5 is a detached assembly view, partly in 10d; cross-section and partly in elevation of the barker head and shaft for the same. V

Fig. 6 is a cross section of the barker head substantially on broken line 6-6 of Fig. 5.

Fig. 7 is a detached elevation of one of the Fig. 10 is a sectional view substantially on broken line 10-10 of Fig. 9, showing the lift plate in the housing.

Fig. 11 is a detached plan view of the lift plate.

Fig. 12 is a somewhat diagrammatic fragmentary elevation on a reduced scale showing counter-balancing mechanism for a swinging frame.

Fig. 13 is a diagrammatic plan view of an alternative form of feed and guide means.

Fig. 14 is a sectional View on line 14-14 of Fig. 13.

Like reference numerals designate like parts throughout the several views.

The main frame of the machine may consist of upright frame members 12, transverse frame members 13 and longitudinally extending frame members 14 all connected together to form a strong and substantial supporting structure on which the mechanism embodied in this invention may be mounted.

In a general way the barking mechanism embodies a knife or barker head which rotates at a high rate of speed together with suitable feed roll conveyor mechanism for conveying slabs or pieces of material of non-uniform and uneven size and shape to said rotating barker head and mechanism for gauging the depth of cut of the barker head into the material whereby the bark will all be removed from each piece of wood.

The mechanism for feeding the slabs or pieces of wood endwise to the rotary barker head embodies a horizontal feed table 104 (see Fig. 3) at the forward end of the machine, said feed table having a depressed or trough-like central portion 105 to facilitate reception and support of pieces of material of generally triangular cross section or which are not flat on the side that rests on said feed table. In alignment with the end of the feed table are a plurality of lower feed and supporting rolls 15 mounted on shafts 16, 1'7, 18, 19. 20 and 21. Each feed roll 15 is preferably formed of two disc-like members spaced a short distance apart and having peripheral spur teeth 22, see Fig. 8. The two discs of each feed roll 15 may be integral as shown in Fig. 4. The lower feed rolls 15 on the first shaft 16 and last shaft 21 may each have two feed roll discs 23 mounted at the respective sides thereof and spaced from the feed rolls to cooperate in receiving and guiding and feeding the material or slabs therethrough. The discs 23 are spaced far enough apart to receive the slabs therebetween. This distance may vary depending on the width of the material which is being handled. I find that satisfactory results for ordinary slab wood are obtained by spacing the feed roll members 15 two to three inches apart and the discs 23 eight to twelve inches apart. The lower feed rolls 15 are keyed or otherwise fastened to the shafts 16 to 21 so that they will be rotated with said shafts but the feed roll discs 23 are preferably loosely mounted on said shafts. The shafts 16 to 21 are interconnected by means of sprocket wheels 25 and link belts 26 whereby they may all be rotated at the same speed and in the same direcroll shafts 16 to 21, as with the shaft 19. The motor 27 may be a relatively slow speed motor and the speed reduction afforded by the belt and the link belt transmissions is sufficient so that the feed rolls are moved at the correct speed.

In addition to the lower feed and supporting rolls 15, I provide two upper toothed feed and positioning rolls and 36 disposed in front of, and to the rear of, the rotary barking head respectively, at a distance above the lower feed rolls. The foremost upper feed roll 35 is secured on a shaft 37 which is journaled in the movable end of a forked bracket member 38. The other end the bracket member 33 is pivotally mounted for swinging movement on a shaft 39 which is jcurnaled on the frame. The shaft 37 has a sprocket wheel 40 thereon, which is connected by a link belt 41 with another sprocket wheel 42 on the shaft 39. The shaft 39 is connected by spur gears 43 with another shaft 44 which is driven from the shaft 16 by link belt 45 operating on

sprocket wheels

46 and 47. The shaft 39 is positioned directly above the shaft 44, as shown in Fig. 2, but for purposes of illustration, these shafts are schematically shown in a different relative position in 4. The spur gears 43 serve to rever e the direction of rotation in the train of driving mechanism which drives the upper feed roller 35 whereby the lower periphery thereof will moving in the proper direction to cooperate in advancing the pieces of material through the machine. The forked bracket 38 which carries the upper feed roller 35 is adjustably supported from above by means inciuding a link 146 which is pivotally connected, as by an eye bolt 147, with the bracket 38 and extends upwardly through holes in plates 48 on an overhead supporting bar 49. A nut 50 is provided on the upper end of the link 146 whereby the downward movement of said link 146 is limited and adjustably controlled and the upward movement of the same is freely permitted. When material passes under the feed and positioning roller 35 it will be lifted thereby and will ride on said material, said roller 35 helping to feed the material forward and at the same time, serving as a positioning means as hereinafter ex-v plained.

The rearmost upper feed roller 36 is secured on a shaft 51 which is mounted in a forked swinging bracket 52. The rear end of bracket 52 is mounted on a shaft 53 which is journaled in the frame. A link 54 pivotally connected with bracket 52 by eye bolt 55 extends upwardly through plates 56 on overhead frame bar 49 and has a nut 57 on the top end thereof, whereby up and down move ment of the feed roll 36 is permitted the downward movement being limited by engagement of the nut 57 with the plates 56. Shaft 51 is connected by sprocket wheel 58 and link belt 59 with a sprocket wheel 60 on the shaft 53. Shaft 53 is driven from a countershaft 61 by

sprocket wheels

62 and 63 and link belt 64. The countershaft 61 is connected by spur gears 65 with the driven feed roll shaft 21 thereby completing a train of driving mechanism which drives upper feed roll 36 at the correct speed and in the correct direction to advance the material on which it rests and yet permits up and down movement of said feed roll.

A material discharging roll 66 having an accelerated speed driving connection with shaft 21 by means of

sprocket wheels

67 and 68 and link belt 69 is provided at the discharge end of the machine and completes the material feeding bark just in advance of the barker knife.

and handling part of the mechanism. As soon as a piece of material which has passed the barking knife comes onto the roll 66 and is released by

rolls

36 and 15 it is ejected clear of the machin by the more rapidly rotating roll 66. The bark removing mechanism embodies a rapidly rotating barker head formed of a body portion '79 keyed or otherwise non-rotatably secured to a shaft 71 which is journaled in suitable bearings in a swinging frame 72, said swinging frame preferably being formed of two spaced apart parallel channel bars are fulcrunied on the transv rse shaft 53. The bars of frame '72 preferably have rearwardly extending portions 7 3 upon which is mounted an adjustable counterweight 74. By adjusting the counterweight 74 enough load may be taken off the rotary barker head so that the knives '1 cut to the desired depth in the material wh: h is being barked but will rise up in case they encounter any obstruction as a hard knot or a stone, which might otherwise break the knives. This counterweight also tends to prevent the barking head from coming down too fast and entering the wood too deeply after it has been raised. To further reduce this tendency I provide a shock absorber which may be in the nature of a cable 119 secured to the swinging frame 72 and extending upwardly over a pulley ill, 2, and having a weight 112 secured to its other end. A ratchet wheel 113 and pawl ll i allow rotation of pulley 111 as the frame 72 is raised but prevent rotation of such pulley 111 as the descends thereby compelling the cable to slide over the pulley 111 and frictionally retarding the down-- ward movement of the barker head. The body portion 7c of the barker head is of larger diameter at the ends and decreases gradually in diameter from both ends inwardly to a point midway between said two ends and body grooved longitudinally as at Fig. 6, for the reception of knives or blades ?6 which are held within the grooves 75 by locking members 77. Set screws '78 in the looking it rnbers 7'! are arran ed to be expanded against the walls or" the grooves '35 to secure the locking members 77 and knives 76 within said grooves. The knives 76 are curved concaveiy to correspond to the curvature of the body 70 whereby they will conform approximately to the curved or segmental crosssectional shape of the slab of material from which the bark is being removed The rotary barker head is mounted within a housing 79, Figs. 1, 2, 9 and 10, which covers the top and sides of said barker head out is open the bottom to allow the knives '76 to engage the material to be barked. The housing 79 is pivotally supported from the cutter shaft '71 and is provided on each side with forwardly and up wardly extending arms so of a general goose neck shape, the forward ends 81 of which arms rest upon the top edges of the bracket 38. As the lever arms 94 and links 95 (hereinafter described) permit only such oscillation of the housing 79 on the shaft 71 as is necessary to maintain proper positioning of the housing, the position of the barker head will be partially determined by the up and down movement of the upper feed roll 35 as it rides upon the bark surface of the material immediately in front of the location at which said bark surface passes under the barker head. A lift plate 82 is pivotally mounted within the barker head housing 79 directly in front of the barker head and is arranged to ride on the The lift plate 82 has a bark engaging surface 83 and is mounted for oscillation on a pivot rod 84 which extends crosswise between the two sides of the barker head housin'g"79. A lever arm 85 which is integral with the plate 82 extends upwardly from the pivoted portion of the lift plate and is pivotally connected with one end of a link 86, whereby arm '85 and plate 82 oscillate' as a unit. The other end of the link 86 is pivotally connected with the lower end of a downwardly extending lever arm 87 which is secured to a transverse shaft 88. The'shaft 83 has an upwardly extendlever arm 89 which is pivotally connected with a nut member 90 which is internally thre'adof cut of the barker head may be varied. The

depth of cut of the barker head is thus predetermined by the operator, who adjusts the out to conform to the depth of bark he is removing, by turning the screw 91. Obviously, other means housing is provided with a removable'wear shoe 93 which may come in contact with the ma terial after it has passed under the barker head and which tends to prevent the barker head from cutting too deeply after the'piece has passed the positioning means in front of said head. This prevents the head from cutting too deeply into The screwshaft '91 eX- as may be used in place of screw 91 to adjust the lift plate 82. The rear end of the barker head the extreme rear end of the piece of material just as said piece is leaving the knife. The barker head housin '79 is rigidly connected at its two ends with upwardly extending lever arms 94. The upper ends of the lever arms 94 are pivotally" connected with the forward ends of links 95 The rear ends of the links 95 are connected with the frame by a common pivot 95 which is dis posed substantially directly above the pivot shaft 53 so that the barker head housing will be automatically' oscillated on its pivot 71 when the frame 72 on which the barker head is mounted is raised or lowered. This link and lever mecha-' nism operates automatically to keep the barker head housing always in the proper position and the lift plate 82 and wear shoe 93 always substantially parallel to the work and in correct which mechanism operates similar to the paral lel link and lever mechanism which maintains the housing in a cutting position. The barker head is driven at relatively high speed in the direction indicated by the arrow in Fig. 6, by a motor 97 having a pulley 98 which is connected by multiple belt 99 with a suitable pulley 100 on the shaft 71. The drive shaft of the motor 9'7 is essentially disposed in alignment with the shaft 53 upon which the swinging frame 72 is mounted whereby the tension of the belt 99 will not varied by raising and lowering movement of the barker head.

Bumper or stop means, indicated at 102 is provided between the movable end of the swinging frame '72 and the main frame of the machine for arresting the downward movement of the barker so that it can not come in contact with the lower feed rolls.

In Figs. 13 and 14 I have shown, somewhat diagrammatically, a plan view of a lower feed and guide arrangement which, for some kind of irregularly shaped slabs is preferable to the corresponding lower feed and guide means shown in the preceding figures. In this form of feed and guide mechanism I provide an additional or third feed roll 105 on each of the shafts 16 to 21 inclusive on the outer sides of the feed rolls 15 and relatively close to said rolls 15. The feed rolls 105 may be adjustable toward and away from the feed rolls 15 and are preferably close enough to one element of the rolls 15 so that a thin piece of slab wood, as a two by four, may be placed edgewise thereon and rest on the rolls 105 and one element of the rolls 15. These extra feed rolls 105 also afford a third line of support for flat slabs. Fixed guides 106 at the sides of the rolls 15 and 115 are used in place of the discs 23 disclosed in Figs. 1 to i.

' In the operation of this barking machine the wood to be barked which will usually be in the form of slabs several feet long and of irregularly shaped cross-section having bark on their curved sides, is fed to the machine by passing said slabs endwise over the feeding table 104 and causing them to enter between the lower feed rolls l5 and upper feed roll 35, which will grasp the slabs and advance them one at a time to the rotating barker head. The mounting member 38, which supports the feed roll 35, is pivotally mounted. The link 146 limits the downward travel of the free end of the member 38, that is, the end which mounts the feed roll 35, at a point where the feed roll will not engage the feed roll 15, and where the feed roll 35 will be positioned below the top surface of the entering slabs. The enterings slabs raise the feed roll 35 and the mounting member 38. The swinging frame '72 and its parallel link are each pivoted at one end upon fixed pivots mounted on the frame member 12. The other ends of the link 95 and the frame '72 are pivot- .ally connected through movable pivot points one to the arm 94, which is fixedly secured to the housing '79, and the other to the housing '19. By this apparatus the housing 79 and the cutter head may be moved up and down with the swinging of the frame "12 and the relative vertical position of the housing 79 maintained regardless of such swinging. The forward end portions 81 are positioned over the mounting member 33 and cause the frame '72 to rise with the mounting member 38. The cutter head is positioned lower than the feed roll 35, so that the cutter head will only be initially positioned by the rise of the feed roll 35. The final positioning of the cutter head is accomplished by the lift plate 82. In order to provide for means to externally adjust the lift plate 82, I provide the additional parallel link action by the link 36 and the swinging frame 72, where the link 86 is mounted to the frame 12 through an adjustable pivot and the swinging frame 72 is mounted in the frame 12 through a fixed pivot. The other ends of the frame 72 and the link 85 are each connected with the link 85 and have movable pivotal connections therewith. The connection of the frame This parallel link mechanism permits the frame '72 to swing without effecting the adjustment of the lift plate 82 as respects the cutter head. Before each slab is engaged by the barker head the advancing end thereof will pass under the lift plate 32 which will further and more accurately position said barker head so that it will out to a depth which has been predetermined by the operator by his setting of the feed screw 91. As the slab passes out from under the rotating barker head it will be engaged by the wear shoe 93 which will maintain a constant depth of out after the slab has passed the lift plate thus preventing too deep a cut in the rear end of each slab. The front feed and positioning roll 35 and the lift plate 82 and the wear shoe 93 all cooperate as guide means to insure an even and clean removal of the bars. If any one or even two of these gauge members drop into depressions in the bark or wood, or off of the end of a piece of wood, the other gauge member, or members will hold the barker head at the proper elevation to insure a clean even removal of the bark. The feed mechanism including the lower rollers 15 and the feed roll discs 23 or guides 106, and the up er feed

rollers

35 and 36 permit a correct positioning of each slab regardless of the cross sectional shape of the same so that the bark side thereof will be presented most advantageously to the barking roller. The two elements of each lower feed roller 15, being spaced apart will permit the corner of a slab of triangular cross section to extend therebetween so that this type of slab is advanced with the bar side uppermost. The guard rollers 23 align and position the slabs so that they will be fed straight to the barker head and the upper feed rollers hold the slabs down firmly on the lower rolls 15 th .5 insuring an even and positive feed, and preventing the movement of the slabs from being influenced by the rapidly rotating barker head, which preferably rotates in such a direction that the knives are moving in the opposite direction from the slab when they encounter the bark. The bark engaging surface of the lift plate 82 is curved to conform to the curvature of the bark on a slab allowing the slab to automatically adjust itself to the barker head.

Obviously, changes may be made in the forms, dimensions, and arrangement of the parts of my invention, without departing from the principle thereof, the above setting forth only preferred forms of embodiment.

I claim:

1. In a slab barking machine a plurality of sets of driven feed rolls arranged in substantial feeding alignment; each set comprising a plurality of laterally spaced apart peripherally spiked disc like members parallel to the line of feed affording clearance therebetween for projecting portions of a slab; feed roll guard discs of larger diam ter than said feed rolls at the sides of said feed rolls and spaced farther apart than said feed rolls whereby slabs are correctly positioned on said feed rolls, and a rotary barker head positioned above said sets of feed rolls.

2. In a slab barking machine a plurality of sets of driven feed rolls arranged in substantial feeding alignment; each set comprising a plurality of laterally spaced apart peripherally spiked disc like members parallel to the line of feed affording clearance therebetween for projecting portions of a slab; shafts whereon said feed rolls are fixedly mounted; guard discs of larger diameter than said feed rolls loosely mounted on said shafts at the sides of said feed rolls, and a rotary barker head positioned above said sets of feed rolls.

3. In a slab barking machine a plurality of sets of driven feed rolls arranged in substantial feeding alignment; each set comprising a plurality of laterally spaced apart peripherally spiked disc like members parallel to the line of feed aifording clearance therebetween for projecting portions of a slab; a feed table at one end of said sets of rolls, said feed table having a trough like groove in alignment with he clearance space between said feed rolls, and a rotary barker head positioned above said sets or feed rolls.

4. In a slab barking machine a plurality of of driven feed rolls arranged in substantial feeding alignment, each set comprising a plurality of laterally spaced apart pei heraliy spiked disc like members parallel to the line of feed affording clearance therebetween for projecting portions of a slab; a feed table at one end of said sets of rolls; sal feed table having a trough like groove in alignment with the clearance space between said iced rolls; feed roll guard means positioned at the sides of said feed rolls and spaced farther apart than the feed rolls of said sets, and a. rotary barker head positioned above said sets of feed rolls.

5. In a barking machine for wood slabs, a plurality of sets or" driven lower feed rolls mounted in substantial feeding alignment in a common plane; each set comprisin a plurality of laterally spaced apart disc like members parallel to the line of feed having periph al slab engaging teeth and affording clearance erebetween for projecting portions of a wooden slab; feed roll guard discs of greater diameter than said lower feed rolls coaxial with said lower feed rolls and spaced on opposite sides thereof; upper feed rolls mounted above said sets of lower feed rolls, and a rotary barker head positioned above said lower feed rolls.

6. In a barking machine for wood slabs, a plurality of sets of driven lower feed rolls mounted in substantial feeding alignment in a common plane; each set comprising a plurality of laterally spaced apart disc like members parallel to the line of feed having peripheral slab engaging teeth and affording clearance therebetween for projecting portions of a wooden slab; feed roll guard discs of greater diameter than said lower feed rolls coaxial with said lower feed rolls and spaced on opposite sides thereof; vertically movable upper driven feed rolls mounted above said lower feed rolls and extending below the level of the upper peripheral portions of said guard discs, and a vertically movable rotary barker head positioned above said lower feed rolls.

'7. In a barking machine for wooden slabs, a plurality of sets of driven lower feed and supporting rolls arranged in substantial feeding alignment with their upper peripheries in a substantially horizontal plane, each of said sets of rolls comprising three disk members laterally spaced apart unequal distances and parallel to the line of feed, such distances being substantially great compared to the diameter and the width of the contact faces of said disks; upper feed rolls mounted above said lower feed disks, fixed guide members spaced on opposite sides of said feed disks whereby wood slabs on said feed disks may be guided by said guide members, and a rotary barker head positioned above said sets of feed rolls.

8. In a machine for barking wood slabs; lower driven feed rolls forming slab supporting and advancing means; a vertically movable upper roll disposed to engage the top surface of the advancing slabs; bracket means for mounting said roll; a vertically movable rotary barker head disposed above the advancing slabs, frame means for mounting said barker head; and means connected to said rotary barker head frame means positioned above and in the path of the br cket of said vertically movable upper roll, whereby the lower vertical position of said barker head will be limited by the lower vertical position of said upper feed roll and whereby said barker head will be free to rise without moving said upper feed roll.

9. In a machine for barking wood slabs; lower driven feed rolls forming slab supporting and advancing means; an upper feed roll arranged to engage the top surface of the advancing slabs; vertically movable bracket means supporting said upper feed roll; a rotary barker head disposedin the path of the upper portion of the advancing si es; vertically movable frame means support ing said barker head; and barker head positioning devices interconnecting said barker head frame and said upper feed roll bracket, said positioning means comprising a member connected to the barker head frame means and having a vertically adjustable projection positioned above and in the path of said upper roll bracket means, whereby the lower vertical position of said barker head will be limited by the lower vertical position of said upper feed roll and whereby said barker head will be free to rise without moving said upper feed roll.

10. In a machine for barking wood slabs; a frame; lower driven feed rolls forming slab supporting and advancing means on said frame; an upper feed roll positioned to engage the top surface of the advancin slabs; a swinging bracket supporting said upper feed roll; a vertically movable rotary barker head disposed above said lower feed rolls; a swinging frame supporting said barker head; friction means retarding downward movement of the movable end of said swinging frame, and means extending outwardly from the end of the swinging frame and positioned above and in the path of said upper feed roll bracket, whereby the lower vertical position of said barker head will be limited by the lower vertical position of said upper feed roll and whereby said barker head will be free to rise without moving said upper feed roll.

11. In a machine for barking wood slabs; lower driven feed rolls forming slab supporting and advancing means; a vertically movable upper feed roll disposed to engage the top surface of the advancing slabs; a vertically movable rotary barker head disposed in the path of the upper side of the advancing slabs; a housing for said barker head; a lift plate adjustably mounted in said housing in advance of said barker head and in the path of the upper surface of the advancing slabs, and means operable from the forward end of the machine for adjusting said lift plate whereby the depth of out of said barker head may be predetermined.

12. In a machine for barking wood slabs; lower driven feed rolls forming slab supporting and advancing means; a vertically movable upper feed roll disposed to engage the top surface of the advancing slabs; a vertically movable barker head disposed in the path of the upper side of the advancing slabs; a housing for said barker head; a lift plate adjustably mounted in said housing in advance of said barker head and in the path of the upper surface of the advancing slabs; and means operable from the exterior of the machine for adjusting said lift plate, whereby the depth of cut of said barker head may be predetermined and readily changed during the operation of the device.

13. In a slab barking machine, a plurality of sets of driven, slab engaging, lower, feed rolls arranged in substantial feeding alignment, each set comprising a plurality of laterally spaced apart peripherally spiked disc like members parallel to the line of feed affording clearance therebetween for projecting portions of a slab; driven slab engaging upper feed rolls mounted above said lower feed rolls; a vertically movable rotary barker head operable in a plurality of cutting positions between said lower feed rolls and extending below the upper surface of said lower feed rolls when in its lowermost position; and stop means for said vertically movable barker head arresting the said vertically moveable barker head in its lowermost position and preventing contact between said vertically movable barker head and the said lower feed rolls.

14. A barking device comprising a plurality of laterally spaced apart rows of lower driven supporting and advancing means positioned parallel to the line of feed afiording clearance therebetween for the projecting portion of a wood slab, each of said rows embodying a plurality of longitudinally spaced apart supporting and advancing members having slab engaging teeth thereon; driven, slab engaging, upper, feed means mounted above said lower driven supporting and advancing means; a vertically movable rotary barker head operable in a plurality of cutting positions between said longitudinally spaced apart supporting and advancing means and extending below the upper surface of said lower supporting and advancing means when in its lowermost position; and stop means for said vertically movable barker head arresting the said vertically moveable barker head in its lowermost position and preventing contact between said vertically movable barker head and the said lower feed rolls.

JOSEPH GRU'BER.