US3645308A

US3645308A - Log-levelling machines

Info

Publication number: US3645308A
Application number: US886496A
Authority: US
Inventors: Philip Nilsson
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-12-20
Filing date: 1969-12-19
Publication date: 1972-02-29
Anticipated expiration: 1989-02-28
Also published as: DE1955293A1; NO130349B; JPS4824479B1; CA924222A; DE1955293B2; FR2026652A1; SE339389B

Abstract

A log-levelling machine having at least one rotary cutter in the shape of a conical disc and a device for advancing logs in their longitudinal direction toward the rotary cutter or cutters. The machine operates to flatten the logs on their lateral sides by cutting the excess material into chips. According to the invention, that portion of each rotary cutter which is located next to the flattened surface of a log which is being cut is provided with a set of teeth adapted to cut chips of substantially smaller thickness than the chips cut by the remaining teeth of the cutter.

Description

United States Patent N ilsson Feb. 29, 1972 [54] LOG-LEVELLIING MACHINES [72] lnventor: Philip Nilsson, Kaptensgatan 3A,

Soderhamn, Sweden [22] Filed: Dec. 19, 1969 21 Appl. No.: 886,496

[30] Foreign Application Priority Data Dec. 20, 1968 Sweden ..17591/68 [52] US. Cl ..144/176,144/118,144/3 P [51] Int. Cl ..B27l 11/02, B27c 1/08 [58] Field of Search ..144/l76, 162, 326, 3-14,

[56] References Cited UNITED STATES PATENTS Tomlinson "114/176 1 Standal 144/162 PHmaryEiaminer-Donald R. Schran AttorneyBrumbaugh, Graves, Donohue & Raymond 57 ABSTRACT A log-levelling machine having at least one rotary cutter in the shape of a conical disc and a device for advancing logs in their 7 Claims, 2 Drawing Figures PAIENIEDFEm m2 s.s45,30e

INVENTOR fi P Amara/V 5 his A TORNEYS LOG-LEVELLING MACHINES BACKGROUND OF THE INVENTION The present invention relates to an improvement in socalled log-levelling machines or canters. Such machines provided with at least one and normally two opposed rotary cutters-i.e., cone-shaped carriers which support chipper teeth or knives-as well as means for advancing logs in their longitudinal direction into the area between the cutters. The machines operate to make level the logs on two opposite sides by cutting the excess material into pulp chips.

More particularly, the present invention relates to a modification in the teeth of the above-type rotary cutters to achieve an improvement in the cut log surface.

Log-levelling machines having rotary carriers in the shape of conical discs have previously been proposed. Thus, one machine is known which has two opposed discs designed as truncated cones, the narrower ends of which face each other and carry sawblades projecting outside the envelope surfaces of the conical discs. The sawblades operate essentially as ordinary circular sawblades and the material which is located outside of the blades and cut from the log is cut into chips after the sawing operation by knives on the rotary carriers. This type of machine has the disadvantages that it produces a considerable quantity of sawdust and that the chips obtained are not of satisfactory quality.

According to another proposal, two opposed conical rotary discs are provided to serve as tool carriers. Attached to the carriers are separate cutters disposed circumferentially in a spiral and axially in a helix. Each cutter has one edge cutting substantially in a plane containing the grain of the logs at the point of contact and another edge at an angle thereto which cuts transversely to the grain. In practice, the cutting operation is generally called parallel chipping.

Log-levelling machines of this kind operate satisfactorily with the exception of one minor drawback which is particularly marked if the wood is very knotty. This drawback arises from the fact that, next to the surface to be levelled, cutters will at times work against the grain and may thereby tear out parts of the log surface leaving the surface rough. In practice, this problem is not very serious but for certain types of wood, it would be desirable to avoid it.

SUMMARY OF THE INVENTION An object of the present invention, therefore, is to find a way of improving log-levelling machines of the type described above so as to eliminate the log tearing problem and leave a smooth flat surface.

This object, as well as other objects which will become apparent in the discussion which follows, is achieved, according to the present invention, by providing the rotary carriers, on the portion thereof which is located next to the flattened surface of a log, with special cutter teeth or knives for cutting chips of substantially smaller thickness than the chips cut by the other knives of the rotary carriers.

It has been found that the special set of cutter teeth or knives, according to the invention, act to smooth the rough wood surface produced by the remainder of the cutting teeth without additionally tearing material away from the surface of the log.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a rotary cutter or cutting disc having special teeth according to the present invention.

FIG. 2 is a diagrammatical top view of a log-levelling machine employing two opposed rotary cutters of the type shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will now be described with reference to FIGS. 1 and 2 of the draw- The log-levelling machine to which the present invention relates, shown only diagrammatically in FIG. 2, comprises a frame (not shown) in which two cutting

discs

10 and 11 are rotatably joumaled and driven by a motor (not shown). The

discs

10 and 11 have the shape of truncated cones and have their narrower ends facing each other. Further, the discs carry a plurality of cutters 12 which will be discussed in detail below. The

discs

10 and 11, which may be adjustable in direction towards and away from each other, are each adapted to work on one side of a log 13 advanced in a longitudinal direction between the discs. The means for advancing the log. indicated generally at 20, includes

rollers

21, 22 supporting the log. The log is thus made level on two opposed sides by cutting up the excess material into pulp chips.

The log-levelling machine according to the invention is suitable for levelling two opposed sides of a round log and also a log already levelled on two sides so that a square log is obtained. The latter, in fact, is what is shown in FIG. 2.

FIG. 1 shows that, in this example, the conical disc is provided with a number of cutters disposed in a spiral circumferentially and a helix in the axial direction. In the disc that is shown each cutter has a main edge 14 adapted to operate in the same plane as the grain of the log at the point of contact and an edge 15 adjoining the main edge and operating in a plane transverse to the grain. However, it should be stressed that the improvement according to the present invention is not limited to this type of cutter configuration and may also be used in the case of conical cutting discs having elongated knives extending substantially in parallel to the envelope surface of the disc.

According to the present invention, the part of each

cutting disc

10, 11 located next to the level surface of the log-i.e., in the present case the flat narrow end of the conical discis provided with a set of cutters 16 which are adapted to cut chips substantially smaller than the remainder of the chips, especially as regards their thickness.

It is possible to achieve the desired cutting function just mentioned in a number of different ways. In each separate case it is only required, according to the general principle, that the chips out next to the level surface of the log are relatively thin so that the cutting forces become slight and thus also those forces become slight which might otherwise cause large bits to be torn out of the log surface. However, particularly advantageous results seem to be obtainable, according to a preferred embodiment of the present invention, iffor the purpose stated cutters are used which consist of the cutters known per se having a main edge extending in the same plane as the grain of the log at the point of contact and an edge adjoining the main edge and extending in a plane intersecting the grain. These cutters are preferably arranged in a circular row with the main edges located in the same plane perpendicularly to the axis of rotation of the disc in question.

Further, it is convenient according to the present invention to provide the cutters of the particular set, such as the cutters 16, on a separate holder. In the present example this holder is in the form of an annular disc 17 which is preferably readily replaceable and disengagably secured to the central portion of the conical disc.

As illustrated particularly clearly in FIG. 1, the surface of the annular disc 17 facing the log is provided with annular ribs 19 with intermediate grooves 18. Inter alia, said ribs have the purpose of contributing to the guidance of the log while keeping low the friction against the flat log surface.

The ribs 19 and annular grooves 18 have also another important function. Sometimes it is desirable to bring the

cutting discs

10, 11 tightly together to cut an entire log of inferior quality into pulp chips. In such cases, if the discs were quite smooth on the end surfaces thereof which face each other, it might be difficult to bring them entirely together. If, instead, the discs exhibit the ribs 19 and grooves 18, staggered in relation to each other on the two discs so that when the discs are brought tightly together there is formed an arrangement resembling a labyrinth seal, no slot can be formed between the discs.

For the same reason, the special sets of cutters 16 on the

cutting discs

10, 11 may be disposed on the same radius but circumferentially staggered on the two discs. With this latter arrangement, however, the discs should be driven synchronously, preferably by the same drive shaft.

It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and that the same are intended to 'be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. in a log-levelling machine including (a) at least one rotary carrier in the shape of a conical disc having first cutter means arranged on the conical surface of the disc, and (b) means for advancing logs in their longitudinal direction to place a lateral side thereof in contact with said at least one rotary carrier thereby to make the log flat on said lateral side by cutting the excess material on said lateral side into chips, the improvement wherein a portion of said at least one carrier which is located next to the flattened surface of a log is provided with second cutter means for cutting chips substantially smaller than the chips cut by said first cutter means, said second cutter means including a plurality of cutters arranged in a circular row, each of said cutters having a main edge disposed on a common plane and extending in the same plane as the grain of the log at the point of contact with the log and having an edge adjoining the main edge extending in a plane intersecting the grain.

2. In a log-levelling machine including (a) at least one rotary carrier in the shape of a conical disc having first cutter means arranged on the conical surface of the disc, and (b) means for advancing logs in their longitudinal direction to place a lateral side thereof in contact with said at least one rotary carrier thereby to make the log flat on said lateral side by cutting the excess material on said lateral side into chips, the improvement wherein a portion of said at least one carrier which is located next to the flattened surface to a log is provided with second cutter means for cutting chips substantially smaller than the chips cut by said first cutter means, said second cutter means including a plurality of cutters and holder means, to which each of said cutters is secured, and which is disengagably secured to the central portion of said rotary carrier, whereby said second cutter means is readily replaceable.

3. The improvement defined in claim 2, wherein said holder means is an annular disc.

4. The improvement defined in claim 3, wherein the surface of said annular disc facing the log has annular ribs with intermediate grooves.

5. The improvement defined in claim 4, wherein said loglevelling machine includes two rotary carriers arranged in opposite relationship; wherein said log-advancing means is adapted to advance logs in their longitudinal direction between said opposite rotary carriers and wherein said annular ribs and grooves on said the two annular discs of said two rotary carriers are staggered such that the ribs of one of said discs are located axially opposite the grooves of the other disc.

6. The improvement defined in clam 5, wherein said two rotary carriers are driven synchronously.

7. The improvement defined in claim 6, wherein the cutters of one of said discs are circumferentially staggered in relation to the cutters of the other disc so that the discs may be brought tightly together without the cutters forming an obstacle.

Claims

5. The improvement defined in claim 4, wherein said log-levelling machine includes two rotary carriers arranged in opposite relationship; wherein said log-advancing means is adapted To advance logs in their longitudinal direction between said opposite rotary carriers and wherein said annular ribs and grooves on said the two annular discs of said two rotary carriers are staggered such that the ribs of one of said discs are located axially opposite the grooves of the other disc.