US3872902A

US3872902A - Wood-chip cutting machine

Info

Publication number: US3872902A
Application number: US399721A
Authority: US
Inventors: Philip Nilsson
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-21
Filing date: 1973-09-21
Publication date: 1975-03-25
Anticipated expiration: 1992-03-25
Also published as: FR2200091A1; FR2200091B1; CA981159A; NO143562B; SE381601B; FI59215B; DE2347716C2; FI59215C; NO143562C; DE2347716A1

Abstract

A wood-chip cutting machine includes a tool carrier which preferably has opposed concentric annular guide surfaces that extend parallel to the rotational axis and which are radially spaced from each other and which are successively offset from each other in an axial direction, a series of concentric frustoconical abutment surfaces that are axially offset from one another which fill the spaces between the guide surfaces, and a series of cutter tools that are secured to the abutment surfaces with their cutting edges parallel to the adjacent abutment surface, the cutting tools being mutually staggered so that successive cutter tools are disposed on a combined helicoidal and spiral line.

Description

[4 1 Mar. 25, 1975 1 WOOD-CHIP CUTTING MACHINE [76] Inventor: Phi lip Nilsson, Kaptensgaton B a,

82600 Soderhamn, Sweden [22] Filed: Sept. 21, 1973 [21] Appl. No.: 399,721

[30] Foreign Application Priority Data Sept. 21, 1972 Sweden 12174/72 [52] U.S. C1 144/176, 144/162 R, 241/92 [51] Int. Cl. B276 H08 [58] Field of Search 241/92, 278, 293, 296;

144/162 R, 176, I72, 174, 118, 312, 220, 218, 321, 326 R, 326 A, 326 B, 326 C, 326 D [5 6] References Cited UNITED STATES PATENTS 3,250,305 5/1966 Dunbar 144/326 B 3,304,970 2/1967 Altosaar l 144/162 R 3,308,862 3/1967 Traben l 144/162 R X 3,330,315 7/1967 Tomlinson 144/162 R X 3,454,063 7/1969 Mitten 144/326 R 3,461,931 Wexell 144/162 R 3,645,308 2/1972 Nilsson 144/176 3,692,074 9/1972 Nilsson 144/176X 3,746,062 7/1973 Nystrom et a1. 144/176 Primary Examiner-Andrew R. Juhasz Assistant Examiner-JV. D. Bray Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT A wood-chip cutting machine includes a tool carrier which preferably has opposed concentric annular guide surfaces that extend parallel to the rotational axis and which are radially spaced from each other and which are successively offset from each other in an axial direction, a series of concentric frustoconical abutment surfaces that are axially offset from one another which fill the spaces between the guide surfaces, and a series of cutter tools that are secured to the abutment surfaces with their cutting edges parallel to the adjacent abutment surface, the cutting tools being mutually staggered so that successive cutter tools are disposed on a combined helicoidal and spiral line.

6 Claims, 4 Drawing Figures 1 WOOD-CHIP CUTTING MACHINE BACKGROUND OF THE INVENTION This invention relates to a machine by which a wooden log is cut up into wooden chips.

Wood-chip cutting machines are of known types. One type has the disadvantage that under certain weather conditions, the machine may give an undesired high proportion of chips of too small size.

Another machine has the disadvantage that each knife at every passage through a log cuts a slice at an angle to the grain direction and such slice has a comparatively large surface. Therefore, the log is subjected to heavy stresses and consequently, it may start to vibrate. Where such a cutter is designed to function as a plan-reducer, such vibrations result in a poor surface quality on the resulting block. (A plan-reducer is one wherein excess material is cut away from the sides of the log so that the log is made flat on one or on opposite sides.) Where such machine is used as a pure chip cutting machine, such vibrations cause the chips to have an unequal quality. Also, the final end of the log may tend to turn in such a way that the knives of one of the disks cuts nearly perpendicular to the grain direction whereas the knives of the other disk cut nearly in a plane containing the grain direction, in which case slices of very great fiber length are obtained.

Accordingly, it is a principal object of the present invention to provide a chip cutting machine wherein the just-mentioned drawbacks are avoided.

According to the present invention, a tool carrier is provided that has concentric annular guide surfaces perpendicular to the rotational axis and which are radially spaced from each other and each successively offset in an axial direction, a series of concentric frustoconical abutment surfaces that are also axially offset from each other and which fill the spaces between the guide surfaces, and a series of cutter tools secured to such abutment surfaces and projecting therefrom with their cutting edges parallel to the adjacent abutment surface. The cutter tools are mutually staggered so that successive cutter tools are disposed on at least one combined helicoidal and spiral line which, where more than one such line is provided, go into each other and are mutually concentric, so that when logs are fed lengthwise toward the carrier in a plane perpendicular to the rotational axis, the cutting edges cut essentially in a plane at an angle to the grain direction of the log.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description of the accompanying drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

ON THE DRAWINGS 1 modified form of chip cutting machine.

AS SHOWN ON THE DRAWINGS A wood-chip cutting machine provided in accordance with the principles of this invention is shown in FIG. 1, generally indicated by the numeral 10. The machine includes a pair of frusto-conical tool carriers or cutter disks 11, 12 carried on a shaft 13 which is horizontally rotatably supported in a pair of

bearings

14, 15. The shaft 13 is driven by means ofa pulley or other transmission 16, the tool carriers 11, 12 being corotatable with the shaft 13. The frusto-conical tool carriers 11, 12 have their smaller ends facing each other and in this embodiment are secured together in abutting relation. The machine 10 is equipped with suitable guide 'means such as a conical guide roll 17 and a support member 18. The guide means 17, 18 enable a log to be fed longitudinally toward the conical surfaces of the tool carriers 11, 12 perpendicularly to the shaft 13.

As shown in FIG. 2, each of the tool carriers ll, 12 is stepped, that is each surface is composed of a number of concentric annular guide surfaces 19-23 which lie in planes perpendicular to the rotational axis of the shaft 12, and these guide surfaces 19-23 are separated from each and connected to each other by a series of concentric frusto-conical abutment surfaces 24-28. The guide surfaces 19-23 are thus radially spaced from each other and are successively offset in an axial direction, while the abutment surfaces 24-28 are likewise axially offset from each other to fill the spaces between the guide surfaces 19-23. The generatrix ofeach of the abutment surfaces 24-28'forms an angle with the rotational axis, and the radial length of such generatrix is one to four times the radial length of the adjacent annular guide surface 19-23, a preferred ratio being that the generatrix is twice as long as the adjacent annular guide surface. All of the surface'portions 19-28 are concentric with the rotational axis of the shaft 12.

A series of cutter tools 29-33 is so disposed that individual cutter tools are secured to the abutment surfaces 24-28 respectively, and project therefrom. The edges of each cutter tool 29-33 are disposed to lie in a plane parallel to the respective frusto-conical abutment surface 24-28 as is indicated in chain lines in FIG. 2.

As seen in FIG. 3 the successive cutter tools 29-32 are arranged in an angularly staggered manner in a spiral pattern. Beginning with the cutter tool 29, disposed on the surface 28, the next cutter tool 30 is disposed on the surface 27 with a certain angular lag as seen in the direction of rotation, indicated by the arrow, and that the next following cutter tool 31 follows with a corresponding angular lag. In the example shown on the drawings, each of the tool carriers 11, 12 has its cutter tools disposed in four such spiral patterns. As the surfaces 24-28 are axially offset, and as the surfaces 24-28 are concentric with each other, the resulting line on which the cutter tools 29-33 is disposed is a combined helicoidal and spiral line. Where a plurality of such lines is provided, they go into each other and are mutually concentric.

The radial extent of the guide surfaces 19-23, the rotary speed of the tool carriers 11, 12 and the angular lag between the successive cutter tools 29-33 are chosen in such a manner that each cutter tool will cut a strip with as full a cross-section as possible, similar to the cross section of the portion denoted 34 in FIG. 2. While only two

cutter teeth

30, 35 are shown for each tool carrier in FIG. 2, there is also illustrated in chain lines the space through which the other cutter teeth pass during rotation.

Chip cutting takes place on the ends of the log, with the log resting on the guide means 18 which may be referred to as'an anvil plate and which protrudes in between the conical tool carriers or cutter disks ll, 12. The edge portions of the guide 18 is preferably stepped so that the edges of the guide 18 are disposed very close to the planes in which the cutting edges of the cutter tools are moving. As seen in FIG. 3, this anvil plate or guide means 18 is disposed slightly below the rotational axis. As the cutter tools 29-33 pass through a log. the cutting tools have a feeding action on the log so that the log is pulled into the machine, preferably into a more or less complete abutting relationship to the frustoconical surface portions 2428.

In this operation, each cutter tool 2933 has to work on only a strip-shaped portion of the log so that an even and smooth operation of the machine is obtained. The fiber length in the severed portion can never exceed the length of the individual cutting edges even if the end portion of a log should take an inclined position relative to the'central plane between the tool carriers 11, 12 perpendicular to the axis of rotation of the shaft 12.

FIG. 4 illustrates a similar wood-chip cutting machine which has been provided with two additional features. in this embodiment, the machine is constructed as a so-called plan-reducer wherein the tool carriers 11a, 12a are disposed at a small distance from each other which is preferably adjustable. As a log is fed into the machine between the carriers 11a, 12a, the logs are made plane on two opposite sides. In order to further improve the quality of the surface finish, the tool carriers 11a, 12a are provided with

center disks

36, 37 each having cutter tools sized to cut considerably finer chips. The details of the

center disks

36, 37 are known from the prior art and need not therefore be described further.

I claim:

l. A wood-chip cutting machine comprising:

a. at least one tool carrier adapted to be driven about a rotational axis, said carrier having a series of concentric separate annular guide surfaces extending perpendicularly to the rotational axis and radially spaced from one another, said annular guide surfaces being successively offset in an axial direction. said carrier having a series of concentric separate frustoconical abutment surfaces axially offset from one another and respectively filling the spaces between said annular guide surfaces, the generatrix of each of which forms an angle with the rotational axis; and

b. a series of cutter tools respectively secured to and projecting from said frustoconical abutment surfaces, each tool having a main cutting edge parallel to the adjacent frustoconical abutment surface, said cutter tools being so mutually staggered that the successive cutter tools are disposed on a combined helicoidal and spiral line, whereby when logs are fed lengthwise toward said carrier in a plane perpendicular to the rotational axis, said cutting edges cut essentially in a plane at an angle to the grain direction of the log.

2. A chip cutting machine as claimed in claim 1 in which said cutter tools are disposed in a plurality of combined helicoidal and spiral lines which go into each other and are mutually concentric.

3. A chip cutting machine as claimed in claim 1 in which the length of said generatrix is between one and four times the radial length of the adjacent annular guide surface.

4. A chip cutting machine as claimed in claim 3, the length of said generatrix is substantially twice said radial length. 1

5. A chip cutting machine as claimed in claim 2 in which the length of said generatrix is between one and four times the radial length of the adjacent annular guide surface.

6. A chip cutting machine as claimed in claim 5, the length of said generatrix is substantially twice said radial length.

Claims

1. A wood-chip cutting machine comprising: a. at least one tool carrier adapted to be driven about a rotational axis, said carrier having a series of concentric separate annular guide surfaces extending perpendicularly to the rotational axis and radially spaced from one another, said annular guide surfaces being successively offset in an axial direction, said carrier having a series of concentric separate frustoconical abutment surfaces axially offset from one another and respectively filling the spaces between said annular guide surfaces, the generatrix of each of which forms an angle with the rotational axis; and b. a series of cutter tools respectively secured to and projecting from said frustoconical abutment surfaces, each tool having a main cutting edge parallel to the adjacent frustoconical abutment surface, said cutter tools being so mutually staggered that the successive cutter tools are disposed on a combined helicoidal and spiral line, whereby when logs are fed lengthwise toward said carrier in a plane perpendicular to the rotational axis, said cutting edges cut essentially in a plane at an angle to the grain direction of the log.

4. A chip cutting machine as claimed in claim 3, the length of said generatrix is substantially twice said radial length.