US3757839A

US3757839A - Chipper bit and holder

Info

Publication number: US3757839A
Application number: US00141595A
Authority: US
Inventors: S Vanek
Original assignee: Nicholson Manufacturing Co
Current assignee: Nicholson Manufacturing Co
Priority date: 1969-12-08
Filing date: 1971-05-10
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11

Abstract

Bits clamped between fixed blocks and removable blocks are arranged in a spiral row around a hollow rotating chipping drum. Each bit is bent, one form of bit including flat sections defining side plate portions arranged at dihedral angles to a central plate portion, and another form of bit being substantially cylindrically curved. Each bit is clamped between bit-holding blocks engaging opposite bit faces with the bitcutting edge projecting beyond the periphery of the chipping drum. The cutting edges of the flat section bit are straight, and cutting edges of the curved bit are concave with adjacent cutting edges meeting in a cusp.

Description

United States Patent [191 Vanek 1 Sept. 11, 1973 CHIPPER BIT AND HOLDER 3,356,! 14 l2/l967 Noel.....i.. r. 144/162 R x a 47 W 2 i' 1 124122; Wash.

[73] Assignee: Nicholson Manufacturing Company, Primary ExaminerAndrew R. Jwhasz Seattle, Wash. Assistant Examiner--W. D. Bray A W. B h 221 Filed: May 10,1971

Appl. No: 141,595

Related US. Application Data Continuation-impart ofSer. No. 883,038, Dec. 8, 1969, Pat. No. 3,66l,l92.

References Cited UNITED STATES PATENTS [5 7 ABSTRACT Bits clamped between fixed blocks and removable blocks are arranged in a spiral row around a hollow r0- tating chipping drum. Each bit is bent, one form of bit including flat sections defining side plate portions arranged at dihedral angles to a central plate portion, and another form of bit being substantially cylindrically curved. Each bit is clamped between bit-holding blocks engaging opposite bit faces with the bit-cutting edge projecting beyond the periphery of the chipping drum. The cutting edges of the flat section bit are straight, and cutting edges of the curved bit are concave with adjacent cutting edges meeting in a cusp.

6 Claims, 18 Drawing Figures PATENTED 1 i975 3.757. 8239 saw a or 4 lllllni' PATENTEUSEPY I 3.757. 839

SHEU 3 0F 4 Arrae/ygy CHIPPER BIT AND HOLDER This application is a continuation-in-part of the application of Thomas W. Nicholson, Ray B. Jorgensen and Stanley Donald Vanek, Scr. No. 883,038, filed Dec. 8, 1969, for Peripheral Chipper for Round Log Sections which resulted in U.S. Pat. No. 3,661,192.

A principal object of the present invention is to provide chipper bits which can be held securely in the periphery of a chipping drum, yet which can be removed for sharpening and replaced quickly.

A further object is to provide cooperating blocks to engage opposite faces of a bent cutting bit which can be clamped together readily or securing the bit in place.

Another object is to provide a strong cutting bit which cannot be broken easily, and which will have a very effective cutting edge.

FIG. 1 is a side elevation of a representative form of chipper with parts broken away, and FIG. 2 is a transverse section through the chipper taken on line 2-2 of FIG. 1. FIG. 3 is a detail section on line 33 of FIG. 2.

FIG. 4 is a side elevation of the chipping drum on an enlarged scale.

FIG. 5 is a fragmentary enlarged radial section through a portion of the chipping drum showing a bit installation. FIG. 6 is a top perspective of the bit installation shown in FIG. 5. FIG. 7 is an exploded top perspective of such bit installation.

FIG. 8 is a fragmentary enlarged radial section through a'portion of the chipping drum showing another type of bit installation. FIG. 9 is a section through such bit installation taken on line 99.of FIG. FIG. 10 is a top perspective of the bit installation shown in FIG. 8. FIG. 11 is an exploded top perspective top perspective of such bit installation.

FIG. 12 is a top perspective on a further enlarged scale of the bit shown particularly in FIGS. 8 to 11, inclusive. FIG. 13 is a plan of such bit, and FIG. 14 is an end elevation of the cutting edge of such bit. FIG. 15 is a longitudinalsection through the bit taken on line 15-15 of FIG. 14, and FIG. 16 is a longitudinal section through the bit on line 1616 of FIG. 14.

FIG. 17 is a fragmentary plan of a somewhat modified bit, and FIG. 18 is an end elevation of the bit of FIG. 17. v

The present invention is concerned particularly with a cutting bit type and with holders for cutting bits used in a chipper for cutting small log sections into chips. Such chipper includes a hollow body 1 in which a chipping drum 2 is housed. Such drum is mounted for rotation on an axle 3 carrying apulley 4 which can be rolated by one or more belts 5,shown in FIGS. 1 and 2,

driven by a motor 6. Small log sections, and particulary' 7 those of short axial length such as the log wheel L shown in FIG. 2, can be delivered to the chipper by asupply conveyor 7.

The supply conveyor 7 will dump the log wheel L into tilted to incline the axis of the drum 2 so that movement of the drum periphery in contact with the periphcry of the log round will tend to urge the log round to move down to the broken line position shown in FIG. I in which it is supported by the lower end wall of the chipping chamber, and consequently cannot tip over.

The chip-cutting bits 9 are arranged in a spiral row around the chipping drum 2, as shown best in'FIGS. l and 4. Adjacent bits are arranged in sufficiently overlapping relationship so that as the durm turns chips are cut from the log round in successive layers. As shown in FIG. 4, each bit overlays circumferentially the major portion of the width of each adjacent bit in an-axial direction.

As shown best in FIGS. 3, 5, 8 and 9, the cutting bits 9 or 9 are received in apertures in the periphery of the drum 2, and the cutting ends of the bits project outward beyond the periphery of the drum and are spaced from the adjacent walls of the apertures to provide passages through the circumferential drum wall for chips cut from a log section. Consequently, it is necessary to remove the chips from the interior of the drum. For this purpose chip-removing means are disposed within the drum which in the chipper shown in FIGS. 1 and 2 is a chip-deflector plate 10, shown best in FIG. 2 as being inclined axially of the chipping drum for scooping the chips endwise out of the drum during its rotation. Such deflector plate is supported and positioned by struts 11 and 12 secured to the chipper body.

As shown best in FIG. 2, the left wall of the chipping chamber 8 toward which the periphery of drum 2. turns is disposed in convergent relationship to the adjacent portion of the drum periphery. Rotation of the upper portion of such drum toward such wall, in the direction indicated by the arrow, tends to move the log section in the direction of rotation of the: drum periphery and to press the log section against such wall. Continued rotation of the drum engaging one location of the log section will cut successive layers of such location into chips so that such location of the log section will become concave complemental in curvature to the curvature of the chipping drum periphery. As more layers are removed from the log section, such section will move farther into the angle between the converging chipping chamber wall and the chipping drum periphery. If the log section initially is round, it eventually will assume a crescent shape in cross section, as shown in broken lines in FIG. 2.

Because of the directionyof rotation of the chipping drum and the effect of sueh direction of rotation on the movement of the log section, any chips and debris which do not pass through the apertures in the drum periphery will tend to accumulate in the angle between the converging chipping chamber wall and the drum periphery. If excessive material collects in such angle, it can be removed through an opening closed by an access door 13 pivotally mounted on the hollow body by a pivot 14 to swing open from the solid-line closed position shown in FIG. 2. Such clean-out door can be held in closed position by securing the lug or tongue 15 carried by its swinging edge to the adjacent wall of the body l by a bolt 16. Such bolt can be removed and the lug or tongue pulled outward to swing the door open. During operation of the chipper the edge 17 of a plate secured to the body 1 adjacent to the clean-out door 13 serves as an anvilJThe anvil edge 17 is preferably in the form of fingers, as shown in FIG. 3, between which are notches 18 that will enable small pieces of debris and small stones to escape from the space between the converging chipping chamber wall and the drum periphery.

The spiral path around the drum 2 in which the bits 9 are mounted is delineated by a spiral groove 19 in the drum wall and opening into the interior of the drum, as shown best in FIGS. 3, and 8. The apertures 20 in the wall of the drum in which the bits are mounted are located in the bottom of this groove. The bits 9 received in these apertures are bent transversely of circumferential lines of the drum periphery and are disposed at an angle to the drum periphery so that the cutting ends of the bits project outward beyond the drum wall as shown best in FIGS. 5 and 8.

In one form the bent cutting bits 9 have flat sections providing a dihedral cross section including a first plate portion 21 and at least one other plate portion 22 disposed at a dihedral angle to the first plate portion. In the cutting bit shown in FIGS. 5, 6 and 7 two planar side plate portions 22 are disposed in similar dihedral relationship to the central planar plate portion 21 between such side plate portions. One end of the central plate portion 21 is beveled to form a cutting edge 23, and the corresponding end portions of the side plate portions 22 have similar bevels 24 forming cutting edges. The cutting edges formed by

bevels

23 and 24 are disposed in a plane which is substantially perpendicular to the

plate portions

21 and 22 of the cutting bit.

The pair of bit-holding blocks between which each -bit is clamped fits into an aperture 20 in the drum periphery. The bit-clamping blocks shown in FIGS. 5, 6 and 7 include the inner block 30 which is anchored in the inner portion ofa drum aperture 20 by welding 31. Such block has an outwardly inclined end portion, as shown in FIG. 5, which includes a central planar surface 32 and side planar surfaces 33 complemental to the hollow inner side of the flat section bit 9. The slope of the side surfaces 33 provides shoulders 34 at the root ends of such faces against which the inner end of the bit 9 can abut to prevent such bit from being driven inward by engagement of its cutting edges with a log being chipped.

The cooperating outer block 35 is also received in the aperture 20 in registration with the inner block. The inner block 30 has a lug 36 over which the recess 37 in one end of the outer block 35 can fit. The opposite end of the outer block has a central face 38 and side faces 39 disposed in dihedral relationship complemental to the inner block faces 32 and 33 and corresponding generally to the dihedral disposition of the

sections

21 and 22 of the bit 9. The outer block 35 can be held in clamping relationship to the inner block 30 by a bolt 40 extending through an aperture 41 in the outer block and screwed into a tapped aperture 42 in the inner block. The aperture 41 is counterbore to provide a shoulder against which the head of the bolt 40 can bear to press the loose block 35 toward the fixed block 30.

As shown best in FIG. 5, the height of lug 36 is greater than the depth of the recess 37, so that the outer surface of the lug will engage the corresponding surface of the recess when the mating surfaces of the two blocks are spaced apart to provide a recess for reception of the bit 9 between them. The lug 36 and recess 37 are proportioned to serve as a fulcrum at one side of bolt 40 for providing clearance between the root portions of the surfaces between which the bit is engaged at the opposite side of the bolt 40, so that as the bolt is tightened the tips of the

blocks

30 and 35 will clamp the opposite sides of the bit adjacent to its cutting edges, as shown best in FIG. 5.

The type of bit-clamping

blocks

30 and 35 shown in FIGS. 8, 9, l0 and 11 are generally similar to the bitclamping blocks described in connection with FIGS. 5, 6 and 7. In this instance, however, the bit 9' clamped between the blocks has a curved body 21 instead of a flat section body. Such bit is substantially cylindrically curved transversely of a circumferential line of the chipping drum, and the curvature of the bit shown in FIGS. 8 to 16, inclusive, is of the circular arcuate type. Its cutting end is engrailed, being shown in FIGS. 10 to 14, inclusive, as having a central flat bevel 42 and side flat bevels 43 meeting in inclined ridges 44. As shown in FIGS. 10 to 16, inclusive, the resulting cutting edges are concave and meet in cusps formed at the ends of the inclined ridges 44. The ends of the cutting edges formed by the side concave bevels 43 constitute points 45. The cusps and end points of the engrailed cutting edge effect an initial penetration of the wood followed by a slicing action of the concave cutting edges which produces a very smooth cutting action rather than a chopping action.

For holding such a curved bit between the clamping blocks 30 and 35 the inner block 30 has a convex surface 32' substantially complemental to the concave surface 38' of the outer block 35. Such complemental concave and convex surfaces are formed so that the clamping effect on the curved bit 9 will occur principally at a location adjacent to the cutting end of the bit as shown in FIG. 8, and also principally on the central portion of the bit rather than on the bit edge portions, as shown in FIG. 9, to avoid application of pressure to the bit which might tend to break it.

The end of a new bit can abut the shoulders 34' at the root of the convex bit-engaging surface 32' of block 30. As the bit is shortened by sharpening its cutting edge, it is desirable to compensate for such shortening by building onto the inner end of the bit. For this purpose the inner end of the bit may have notches 46 in it as shown in FIGS. 12 and 13, in which babbitt lug 47 can be cast to abut the shoulders 34' of the block 30 to deter inward slippage of the bit.

While the curved cutter bit can be of circular arcuate cross section, the bit curvature may be modified, such as shown in FIGS. 17 and 18, so that the curvature of the side portions of the bit body is somewhat sharper than the central portions. Such sharper curvature can be effected by making the bit cross section of compound curvature or of elliptical parabolic, or hyperbolic arcuate curvature. In the case of an elliptical curvature the central plane of the bit body would substantially coincide with the minor diametral plane of the elliptical are. All such curvatures are intended to be embraced within the designation of a substantially cylindrically curved bit, the definition of a cylindrically curved surface being traced by a straight line moving parallel to a fixed straight line and intersecting a fixed curve. It is preferred that the curvature of the bit be such that its cross section is symmetrical about a central longitudinal plane of the bit.

In the bit of FIGS. 17 and 18 the cutting end again is engrailed, being formed by a central flat bevel 42' meeting side flat bevels 43 in ridges 44'. Again the resulting engrailed cutting edge includes central and side concave cutting edges meeting at cusps and having end points 45'. The cutting action of the engrailed cutting edge of the bit shown in FIGS. 17 and' 18 is similar to that of the bit shown in FIGS. 12 to 16, inclusive, but the chip cut will be of slightly different shape.

In both the bits of FIGS. 12 to 16 and of FIGS. 17 and 18 it is preferred that the cusps and end points of the cutting edges be disposed in a plane substantially perpendicular to the body of the bit, and consequently substantially perpendicular to the fixed straight line and to the generating straight lines which generate the opposite concave and convex faces of the curved bit body.

I claim:

I. In a peripheral chipper including a hollow rotary chipping drum having apertures in its periphery for mounting a plurality of bits therein, respectively, with their outer ends forming cutting edges projecting generally tangentially from the drum periphery, the improvement comprising pairs of bit-holding blocks for clamping each of the bits separately between the blocks of the respective pairs, each block pair including an inner block fixedly mounted in an aperture of the drum and engageable by the inner face of a bit and an outer block engageable with the outer face of such bit and securable in bit-clamping relationship to said fixed inner block.

2. in the peripheral chipper defined in claim 1, a bolt accessible from the exterior of the chipping drum to effect rotation thereof, connecting the blocks of one pair and located between the circumferential ends of such block pair, the blocks of such pair being formed to provide a bit-receiving slot therebetween at the leading side of said bolt in the direction the bit is moved by rotation of the chipping drum and the blocks being formed for engagement at the trailing side of said bolt in the direction the bit is moved by rotation of the chipping drum to constitute a fulcrum.

3. In the chipper defined in claim 1, a bit adapted to be clamped between the blocks of a block pair and having a cutting edge curved relative to a line extending through a portion of said cutting edge and transversely of the direction in which the bit is moved by rotation of the chipping drum.

4. In the chipper defined in claim 3, at least a portion of the bit being bent substantially arcuately about an axis extending generally circumfe-rentially of the chipping drum.

5. In the chipper defined in claim 1, the bit including two substantially flat sections extending substantially the full length of the bit in the direction in which the bit is moved by rotation of the chipping drum and forming a dihedral angle therebetween.

6. In the chipper defined in claim 5, the bit having three substantially flat sections extending substantially the full length of the bit in the direction in which the bit is moved by rotation of the chipping drum and including a central section and opposite side sections, said opposite side sections being disposed at dihedral angles to said central section.

@2 3 I UNITED STATES PATENT OFFICE p CERTIFICATE OF CORRECTION Patent No. 3 757, 839 Dated September 11'. 1973 Inventor(s) Stanlg D. Vanek It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1,

lines

35 and 36, cancel "top perspective" (second instance).

Column 4, line 17, after "central" insert chamfer or-; same line, after "side" insert -chamfers or; line 22,

cancel "concave" and insert chamers or-- line 54, after "curvature" insert a comma; same line, after "elliptical" insert a comma; line 67, after "central" insert --chamfer Column 5, line 1 after "side" insert -chamfers or-; line 17, cancel "In a" and insert A-; same line, cancel "including" and insert --comprising--; line 18, after "having" insert --a cylindrical shell with-- same line, cancel "in' its periphery" and insert -extending through said shell and arranged in a spiral row around said shell-- lines 21 and 22,

cancel "the improvement comprising"; line 25, cancel "the" and insert -'said Column 6, line 6, after "engagement" insert -within the drum shell aperture in which they are received-- Signed and sealed this 9th day of July 1974.

(SEAL) Attest:

McCOY M. GIBSON; JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents

Claims

1. In a peripheral chipper including a hollow rotary chipping drum having apertures in its periphery for mounting a plurality of bits therein, respectively, with their outer ends forming cutting edges projecting generally tangentially from the drum periphery, the improvement comprising pairs of bit-holding blocks for clamping each of the bits separately between the blocks of the respective pairs, each block pair including an inner block fixedly mounted in an aperture of the drum and engageable by the inner face of a bit and an outer block engageable with the outer face of such bit and securable in bit-clamping relationship to said fixed inner block.

4. In the chipper defined in claim 3, at least a portion of the bit being bent substantially arcuately about an axis extending generally circumferentially of the chipping drum.