US3777793A

US3777793A - Knife holder in log slabbing chipper

Info

Publication number: US3777793A
Application number: US00252230A
Authority: US
Inventors: F Miller
Original assignee: CHIPPER MACHINES AND ENG CORP
Current assignee: USNR LLC; CHIPPER MACHINES AND ENG CORP
Priority date: 1972-05-11
Filing date: 1972-05-11
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11
Also published as: AU5331973A; JPS5344719B2; AU472799B2; JPS4949276A; CA956548A

Abstract

The chipper comprises a rotor with a plurality of knives adapted to slab off the side of a log so that the first saw cut following the chipper removes a usable board. In order to make usable pulp chips, the chipper knives are of bent configuration, each having a grain cutting portion which cuts across the grain and a planing portion which cuts parallel with the grain to leave a smooth board surface on the log as it is moved lengthwise past the chipper on a saw carriage. Each knife is clamped rigidly in working position by a clamp plate which is tightened on a pair of wedges adjacent the side edges of the knife. The clamp plate is crowned, causing it to flatten against substantially the whole area of the knife when the clamp plate is tightened on the wedges.

Description

[ Dec. 11, 1973 1 KNIFE HOLDER IN LOG SLABBING CHIPPER [75] Inventor: Frederick L. B. Miller, Lake Oswego, Oreg.

[73] Assignee: Chipper Machines and Engineering Corporation, Lake Oswego, Oreg.

Filed: May 11, 1972 Appl. No.: 252,230

[56] References Cited UNITED STATES PATENTS 11/1892 Quinn 144/225 11/1966 Standall.. 144/220 3/l97l Hickman 144/220 Primary Examiner-Donald R. Schran Attorney-Lee R. Schermerhorn [57] ABSTRACT The chipper comprises a rotor with a plurality of knives adapted to slab off the side of a log so that the first saw cut following the chipper removes a usable board. In order to make usable pulp chips, the chipper knives are of bent configuration, each having a grain cutting portion which cuts across the grain and a planing portion which cuts parallel with the grain to leave a smooth board surface on the log as it is moved lengthwise past the chipper on a saw carriage. Each knife is clamped rigidly in working position by a clamp plate which is tightened on a pair of wedges adjacent the side edges of the knife. The clamp plate is crowned, causing it to flatten against substantially the whole area of the knife when the clamp plate is tightened on the wedges.

9 Claims, 16 Drawing Figures PATENTED DEC 1 I973 sum 1 or 4 PAIENTED DEC 1 1 I975 SHEET 2 0F 4 1 KNIFE HOLDER IN LOG SLABBING CHIPPER BACKGROUND OF THE INVENTION This invention relates to an improved knife holder in a woodworking machine such as, but not limited to, a log slabbing chipper or edger.

In conventional practice, chipper knives are secured in the rotor head by clamp plates secured by screws perpendicular to the knife blade. This mounting arrangement requires deep slots in the knives to receive the clamp screws since the position of the knife varies in relation to the clamp screws as the knife becomes narrower from repeated sharpening. The slots complicate the manufacture of the knives, reduce the strength of the knives, introduce undesirable stresses in heat treating and reduce the service life of the knives by limiting the number of times they maybe re-sharpened.

Also, the conventional knife clamping arrangements require a high degree of dimensional accuracy for positive positioning of the interfitting parts and provide'inadequate support for the knife, resulting in frequent breakage. These deficiencies also often result in damage to the knife holder as well as the knife, thereby further increasing the maintenance cost of the machine.

Objects of the invention are, therefore, to provide an improved knife holder in a log slabbing chipper, to provide a knife holder which provides better support for the knife, to provide a knife holder which reduces breakage of both knives and holders, to provide a knife holder which will increase the service life of the knife and to provide a knife holder adapted to receive unslotted knives.

SUMMARY OF THE INVENTION A primary feature of the present invention is the use of unslotted knives. Crowned and tapered clamp plates are flattened against a face of the knife as the clamp plates are tightened on wedges extending along the side edges of the knife. This provides more rigid support for the knife, reducing knife and holder breakage, allows the use of stronger knives which are less complicated to manufacture and, at the same time, allows greater dimensional tolerances to the parts since the angular seat in the knife holder serves to position the knife along with the backing bar assembly.

The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiments illustrated in the accompanying drawings. Various changes may be made, however, in details of construction and arrangement of parts and certain features may be used without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic top plan view illustrating the function of a log slabbing chipper;

FIG. 2 is a view on the line 2-2 in FIG. 1, with parts broken away;

FIG. 3 is a perspective view of the chipper; FIG. 4 is a perspective view of a knife holder in FIG. 3;

FIG. 5 is a back end view of the knife clamp plate showing the crown;

FIG. 6 is a perspective view of a knife;

FIG. 7, 8 and 9 are fragmentary plan views of a knife showing the extent to which it may be re-sharpened for use in the present machine;

FIG. 10 is a view showing the present knife holder mounted on a chipper rotor head;

FIG. 11 is an elevation view of the knife holder;

FIG. 12 is a view on the line 12-12 in FIG. 11;

FIG. 13 is a view on the line l313 in FIG. 11;

FIG. 14 is a view on the line 14--l4 in FIG. 11;

FIG. 15 is a perspective view of a modified rotor head embodying the invention; and

FIG. 16 is a view on the line 16-16 in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a top plan view illustrating diagrammatically the function of chipper machine 10 in slabbing off one side of a log L preparatory for the first cut of vertical band saw S. The log is mounted on carriage 11 for iongitudinal travel in the direction of arrow 12. FIG. 2 shows the position of the log and carriage before they have been shifted over to chipper 10 for the desired depth of cut as represented by the broken line 15'. When this adjustment has been made and the carriage and log are traversed past the chipper, the chipper planes off the flat vertical surface 15 in FIG. 1, producing usable pulp chips of relatively high value. Before chippers were developed for this purpose, the surface 15 was cut by a first pass of the log through band saw S resulting in sawdust of a relatively low value and a slab of no value until reduced to chips in a subsequent operation.

Band saw S rotates over an upper pulley 16 so as to made a downward vertical saw cut 17 in the log. Chipper 10 is adjusted relative tothe vertical plane of the saw so as to produce the desired thickness of board B. Thus, in cutting the first board B, the only waste material of low value is the sawdust from the kerf of saw cut 17. The first saw cut makes a usable board having one side planed.

Chipper machine 10 comprises a base frame 20 rigidly secured to a floor or heavy foundation by bolts 21 in FIG. 3. The frame 22 of the chipper machine is mounted for sliding movement on base 20 and is adjustable toward and away from the vertical cutting plane of the saw by hydraulic cylinders 23 and piston rods 24 connected between base 20 and frame 22 on opposite sides of the machine.

Mounted on the movable frame 22 is a rotor head 25 rotatable on a horizontal axis and driven in the direction of arrow 26 by driven pulley 27. Pulley 27 is belted to a motor in the casing 22. Mounted on rotor head 25 is a plurality of knife holders 30 which incorporate important features of the present invention.

Each knife holder 30 carries a knife 35 which will be described with reference to FIGS. 6 to 9 and 13. The knife 35 comprises a bent blade having a sharpened planing edge portion 36 and a sharpened chip cutting edge portion 37. The planing edge portion 36 planes the smooth, flat surface 15 on the log in FIG. 1 while the chip cutting edge portion 37 cuts off chips on a con- The rear edge 42 of shank portion 41 is provided with a plurality of keyhole slots 43. These slots are chamfered on one side as indicated at 44 in FIG. 7. FIG. 7 is a fragmentary plan view of shank portion 41.

Referring now to FIG. 8, Babbitt material 46 is cast on back edge 42 and interlocked in the chamfered keyhole slots 43. This provides a constant width W which is maintained throughout the life of the knife. Each time the

cutting edge

36, 37 is sharpened, the Babbitt material 46 is removed and the knife is placed in a jig for casting a new layer of the Babbitt material 46. After repeated sharpenings the knife becomes narrower and the Babbitt material 46 increases in width to maintain the constant dimension W as shown in FIG. 9. This allows the knife to be re-sharpened many times before it is too narrow for further use since there are no deep slots to receive the usual clamp screws.

Referring now to FIG. 13, a keeper bar 45 is provided with tapped holes to receive screws 49 which secure a backing bar 50 to the keeper bar. For purposes of fine adjustment, shims 51 are interposed between backing bar 50 and keeper bar 45. This is a permanent adjustment which is not changed when the knives are sharpened. Backing bar 50 is provided with a locating flange 52. These parts form a backing bar assembly which will be referred to again after describing the knife holders 30.

As seen in FIG. 4, each holder 30 has a flat base portion 55 with holes 56 to receive screws for mounting the holder on a flat side 57 of the rotor head 25. The mounting surface 57 appears in FIG. 3. In the present illustration the rotor is octagonal with eight side surfaces 57 each lying in a plane parallel with the rotor axis and each carrying one of the knife holders 30. Thus, the eight flat surfaces 57 are all perpendicular to the rotor end surface 58 in FIG. 3.

Referring now to FIG. 11, each knife holder 30 has a short straight leg 60 perpendicular to base 55 and a long straight leg 61 disposed at an angle of approximately l25 to leg 60. The outer end of leg 61 is supported by a curved back leg 62, the

parts

55, 60, 61 and 62 forming an integral one-piece casting having a chip opening 63 extending therethrough.

Leg portions

60 and 61 of the holder 30 have fiat inside supporting

surfaces

65 and 66 to receive and position the back sides of the

knife shank portions

40 and 41 as shown in FIGS. 12, 13 and 14. Opposed to the supporting surface 66 at the outer end thereof is a flat abutment surface 67 on the leg 61. In a similar manner, base portion 55 is provided with an abutment surface 68 opposed to the knife supporting surface 65. A wedge 70 is welded to abutment 68 and a wedge 71 is welded to abutment 67. These wedge elements may be formed integral with the holder casting 30, if desired. The two exposed wedge surfaces 72 and 73 are disposed in parallel planes.

The knife clamp plate 75 in FIG. has a wedging surface 76 on one side to slide on the wedge 70 and a wedging surface 77 on its other side to slide on the wedge 71.

Surfaces

76 and 77 are disposed in parallel planes. This sliding movement is produced by a single screw adjustment as shown in FIG. 13. The rearward end of clamp plate 75 contains a tapped hole 78 extending parallel with the knife. A screw 80 is secured in hole 78 and projects through a slot 81 in an ear 82 on the rearward side of leg 61 of holder 30 relative to the direction of rotation of the rotor. Clamp plate 75 is pulled to the right in FIGS. 12 to 14 by means of a nut 83 on the screw which bears against the rearward side of car 82, the nut having a groove 84 which enters slot 81. The nut is turned'clockwise to tighten the clamp plate and counterclockwise to loosen it.

Clamp plate 75 is crowned in a transverse arch as indicated by the small angles 85 in FIG. 5. This causes the convex surface 86 of the clamp plate to bear first against the mid portion of knife 35. Then as the clamp plate is pulled rearward by the tightening of nut 83, the

side wedges

70 and 71 flatten the clamp plate, which is resilient, removing the crown and causing surface 86 to bear against substantially the entire surface of shank portion 41 of the knife. At the same time, an angled surface 87 extending along one side of the clamp plate bears against the shank portion 41 of the knife, clamping it firmly against supporting surface 65. The

angular knife seat

65, 66 serves as positioning means for the knife. This dual clamping action against

shank portions

40 and 41 allows the use of two-piece knives, if desired, whereby the shank portion 40 may be a separate knife.

In the above described clamping operation the projection of the knife from the holder is fixed by flange 52 on backing bar 50 which projects into slot 90 in leg 61 of the holder as shown in FIG. 13. Screws 91 enter tapped holes in knife backing bar 50 to secure the backing bar assembly in the holder.

In operation, the log approaches the machine from the left in FIG. 3 and travels to the right so that the cutting strokes of the knives are in a downward direction. The chips pass through openings 63 in the knife holders and, for the most part, are impelled downward into a chip bin or conveyor in the base of the machine. A hood 94 covers the upper portion of the rotor to prevent the upward discharge of stray chips.

In FIG. 3 the end surface 58 of the rotor comprises a smooth, flat, or slightly crowned, plate to bear against and guide the planed surface 15 of the log as it is carried past the chipper by carriage 11. In FIG. 10 the effective plane of this bearing surface is represented by the broken line 96. By means of the shims 51 in FIG. 13, the edges 36 of the knives are adjusted to cut in a plane a very slight distance in an axial direction from the plane 96 to provide a slight clearance space.

The present clamping arrangement employing wedge action on a crowned clamp plate is also obviously readily adaptable to a single flat knife. The invention as thus far described is not limited to chippers.

FIGS. 15 and 16 show a modification wherein the chipping head or rotor has integral knife holders. The rotor 100 has a smooth log-supporting and guiding end surface 101 corresponding to the end surface 58 in FIG. 3. The back end of the rotor has a cylindrical portion 102.

Extending between the

end portions

101 and 102 is a series of flat plate portions 103, each of which recedes radially at its trailing end to provide an opening at 104 for the passage of chips into the inside of the rotor. Knives 35 are the same as shown in FIGS. 6 to 9 having sharpened planing edges 36 and sharpened chip cutting edges 37. On the inside of each plate portion 103 is a supporting surface 66 for knife shank portion 41 and a supporting surface 65 for knife

shank portion Wedges

70 and 71 are mounted on

abutment surfaces

68 and 67. Crowned, resilient clamp plate 75 has slide surfaces 76 and 77 along its side edges engaging the respective wedges. The clamp plate tightening mechanism in FIG. 13 is accessible inside the rotor to tighten the clamp plates against the knives, as described in the first embodiment. The operation of the machine is the same as described in connection with the first embodiment.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

l. A holding means for a woodworking knife comprising a support member having a surface arranged to support one face of the knife, a pair of wedging abutment surfaces opposed to said knife supporting surface along opposite sides thereof, a resilient, crowned clamp plate having a pair of wedge surfaces extending along opposite sides thereof on a back face of the clamp plate for sliding engagement with said wedging abutment surfaces, the crown portion of said clamp plate being arched between said wedge surfaces to engage a mid portion of the oppsite face of the knife, means to slide said clamp plate on said wedging abutment surfaces causing the arch of said clamp plate to flatten against and clamp substantially the whole area of said knife against said supporting surface, and means to hold the knife against said sliding movement.

2. A holding means as defined in claim 1, said wedge surfaces being inclined in a direction to flatten said clamp plate when said clamp plate is moved away from the cutting edge of the knife.

3. A holding means as defined in claim 2, said sliding means comprising a single screw on the back edge of said clamp plate.

4. A holding means as defined in claim 1, said support member having two knife supporting portions disposed in angular relation to each other, one of said wedging abutment surfaces being opposed to one of saidsupporting surface portions and the other wedging abutment surface being opposed to the other supporting surface portion, said clamp plate having knife engaging surfaces opposed to both of said supporting surface portions.

5. A holding means as defined in claim 4 including a rotor having knives each with a planing portion and chip cutting portion, one of said supporting surface portions supporting said planing portion of a knife and the other supporting surface portion said chip cutting portion.

6. A holding means as defined in claim 1, said means to hold said knife against sliding movement comprising a flanged backing bar assembly, and a groove in said support member arranged to receive said flange.

7. A holding means as defined in claim 1, said holding means being open on the back side of said clamp plate for the passage of chips.

8. A holding means as defined in claim 1 including a rotor, said support member comprising an integral structural part of said rotor.

9. A holding means as defined'in claim 8, said rotor being generally frusto-conical in shape with a circumferential series of wall members which recede radially toward their trailing ends to provide a chip opening between the trailing end of each wall member and the leading end of the following wall member, and the inside of each of said wall members containing said knife supporting surface.

Claims

1. A holding means for a woodworking knife comprising a support member having a surface arranged to support one face of the knife, a pair of wedging abutment surfaces opposed to said knife supporting surface along opposite sides thereof, a resilient, crowned clamp plate having a pair of wedge surfaces extending along opposite sides thereof on a back face of the clamp plate for sliding engagement with said wedging abutment surfaces, the crown portion of said clamp plate being arched between said wedge surfaces to engage a mid portion of the oppsite face of the knife, means to slide said clamp plate on said wedging abutment surfaces causing the arch of said clamp plate to flatten against and clamp substantially the whole area of said knife against said supporting surface, and means to hold the knife against said slIding movement.

4. A holding means as defined in claim 1, said support member having two knife supporting portions disposed in angular relation to each other, one of said wedging abutment surfaces being opposed to one of said supporting surface portions and the other wedging abutment surface being opposed to the other supporting surface portion, said clamp plate having knife engaging surfaces opposed to both of said supporting surface portions.

9. A holding means as defined in claim 8, said rotor being generally frusto-conical in shape with a circumferential series of wall members which recede radially toward their trailing ends to provide a chip opening between the trailing end of each wall member and the leading end of the following wall member, and the inside of each of said wall members containing said knife supporting surface.