US3566938A

US3566938A - Chain cutter for debranching and debarking trees

Info

Publication number: US3566938A
Authority: US
Inventors: Georg Wehr; Gotthold Gotze
Original assignee: ROTENBURGER METALLWERKE GmbH
Current assignee: ROTENBURGER METALLWERKE GmbH
Priority date: 1966-03-09
Filing date: 1967-03-06
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02
Also published as: CH461769A; GB1117859A; BE695064A; FI44289B; AT275843B; SE326022B; FR1513070A

Abstract

A chain cutter for debarking and debranching tree trunks and having a plurality of roller members which engage the trunks and which are connected together with a plurality of links to form a link chain. A plurality of cutting teeth are fixed to the outer links of one side face of said chain, one portion of these teeth having cutting edges projecting beyond their associated link towards the trunk, and terminating approximately at a point which is on a line with the points of engagement of an associated roller and the trunk.

Description

United States Patent Inventors Georg Wehr;

Gotthold Gotze, Rotenburg an der Fulda, Germany Appl. No. 620,925

Filed Mar. 6, 1967 Patented Mar. 2, 1971 Assignee Rotenburger Metallwerke Gmbll Fulda, Germany Priority Mar. 9, 1966 Germany 1142786 CHAIN CUTTER FOR DEBRANCHING AND DEBARKING TREES [56] References Cited UNITED STATES PATENTS 1,759,188 5/1930 Davidson 144/208 1,937,073 11/1933 Stuve....... l44/208(-8) 2,948,311 8/1960 McCollum.. 143/32(-4) 2,707,007 4/1955 Shuff 144/208(-35) Primary Examiner- Donald R. Schran Attorney-Stevens, Davis, Miller & Mosher 10 Claims, 13 Drawing Figs.

US. Cl 144/208, 144/2, 143/32, 143/135 Int. Cl B271 1/00, B27b 33/14 Field of Search 144/208- PATENTEU MAR 2197;

SHEET 1 BF 4 PATENTEDHAR 2m: 3,566,938

SHEET u 0F 1 Fig. 5

2 2 7 I \zlwmm W4 INVENTORS Georg Wehr A ORNEYS CHAIN CUTTER FOR DEBRANCHING AND DEBARKING TREES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a chain cutter and, more particularly, to a chain cutter for debranching and debarking trees.

2. Description of the Prior Art In the production of timber, it is normal procedure to debranch and debark the trees immediately after they have been cut, and before they are transported to the sawmill or to the consumer, in order to avoid attack by insects, and to facilitate handling.

At the present time, the debranching and debarking of the felled tree trunks is generally performed mostly by hand with an axe, saw or peeling knife, This not only is time consuming, but often is difficult since the tree trunk has to be worked on from all sides, and therefore results in a relatively large labor expense. Accordingly, various equipment has been developed, by which at least mechanical debarking of the felled tree trunks is performed in order to simplify the timber production and increase output, the trunks having been debranched beforehand.

Apparatus is also known which simultaneously debranches and debarks, and which utilizes a chain cutter as the cutting tool. In these arrangements the chain cutter comprises a link chain which fonns a carrier element, and which either completely encloses the tree trunk, or at least engages a portion of its periphery. However, many difficulties are encountered in those known devices, which difficulties largely result from the fact that the trunk of a tree is generally not a perfect cylindrical body with a straight axis, but is rather an extended object often having an axis which is substantially curved in various directions. Also, the tree trunks usually have a cross section which in addition to decreasing in diameter from the foot of the tree to its top, is completely asymmetrical and has bumps and recesses of various shapes, in addition of course, to branches projecting from the surface of the trunk.

SUMMARY OF THE INVENTION These problems are solved with the apparatus of the present invention which features the use of cutting teeth disposed on the outer links of the chain, at least a portion of the teeth having their cutting edges projecting beyond the associated chain link towards the trunk and terminating approximately at a point which is on a line passing through the points of engagement of a chain roller which is adjacent the cutting edge and the tree trunk. In this way the problem of the chain cutter or its cutting teeth into the surface of the tree trunk lying below the bark, is eliminated when tree trunks having varying diameters are encountered.

According to a further feature of the invention, at least three different shaped and ground teeth follow one another on the outer links, each tooth extending in a direction perpendicular to the longitudinal axis of the chain link. This results irr optimum cutting power and simplifies the removal of the shavings.

It is particularly advantageous to construct the cutting teeth as solid teeth, and a satisfactory path for the chain is achieved if according to a further feature of the invention, the cutting edges of the teeth run parallel to the side faces of the chain links and perpendicular to their longitudinal axes. As a result, both the digging of the the chain into the the trunk, and the lifting of the chain out of the bark as a result of centrifugal force, is prevented. Jamming of the chain cutter when cutting through the branches is also eliminated with the present invention by arranging another portion of the teeth so that their cutting edges project away from the trunk and beyond the tangent which is common to the two rollers associated with the teeth. Also, it is advantageous if, in various successive teeth, the cutting edges of the teeth overlap when looked at in the longitudinal direction of the chain.

Satisfactory results are obtained with cutting teeth of a height of at least 5 between 6 and 33 teeth per meter. and with chains having According to a further feature of the present invention, the cutting teeth each have a top rake and an upper clearance angle of approximately 10,the inner tooth and the middle tooth having a clearance angle on the trunk-engaging side from the cutting edge to the foot of the tooth of approximately 5 or 56, a clearance angle on that side which is remote from the trunk from the cutting edge to the foot of the tooth of approximately 258, and on both sides with a clearance angle from the cutting edge against the direction of movement of approximately 26. Also, the outer tooth may have a clearance angle on that side which is remote from the trunk from the cutting edge to the foot of the tooth of approximately 10, a lateral clearance angle on the side facing away from the trunk from the cutting edge against the direction of movement of approximately 5, and a lateral clearance angle on that side which faces the trunk, from the cutting edge against the direction of movement, of approximately 2%.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention is described in the following by way of example in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagrammatic side view of a member of a link of the cutting chain according to the present invention engaging a tree trunk, the chain link being provided with a cutting tooth;

FIG. 2 is a diagrammatic side view of an embodiment of the chain cutter according to the invention in an extended condition;

FIG. 3 is a diagrammatic end view in the direction of movement of the chain according to the present invention engaging a tree trunk;

FIGS. 4a to 4i show three different cutting teeth of the chain according to the present invention, each in plan view, end elevation, and side view; and

FIG. 5 is a longitudinal sectional view of part of the chain according to the present invention in an extended condition, the section plane containing the axis of rotation of rollers 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 1 to 3 and 5, the chain cutter 1 comprises a link chain serving as a carrier and including rollers 2, outer links 3, inner links 4, and intermediate links 5.

Solid cutting teeth

6, 7 and 8 are mounted on the outer links 3 of the one side face of the chain.

In FIG. 1 there is illustrated a chain cutter member which includes two rollers 2 engaging the trunk 9 to be debarked, and an outer link 3 provided with a cutting tooth 6 on its face, the arrow 10 showing the peripheral direction movement of the chain to which the member belongs. Tooth 6 is mounted on the link 3 in such a manner that its cutting edge 11 terminates approximately at a point 12 which is on a line with the point ofengagement between the upper surface of the trunk 9, and the roller 2 which is adjacent to the cutting edge.

As shown in FIG. 1, the spacing of the point of engagement 12 from the straight line 14, which extends perpendicular to the longitudinal axis 15 of the link 3 and passes through the axis of the roller 2, varies only slightly with varying diameters of tree trunk, as shown, for example, by surface 16 of a tree trunk having a larger diameter than the trunk 9. This prevents tooth 6 from cutting into the surface of the tree trunk, even if the latter has a varying diameter.

The position shown in FIG. I for the cutting edge ll of the tooth 6 is independent of whether only one form of tooth is used in the chain cutter, or whether, as shown in FIG. 2, various forms of teeth are employed.

Referring specifically to FIG. 2, there are shown a few links and roller members of a chain cutter with three differently shaped forms of cutting teeth provided on the links. As shown, an inner tooth 6, intermediate tooth 7 and outer tooth 8, are

provided on successive links 3. However, the teeth do not necessarily have to be arranged in the order shown in FIG. 2, but rather could be mountecht varying spacings, such as for example, on very second, third or fourth link.

The arrow 17 in FIG. 2 shows the peripheral direction of travel of the chain, and as can be seen in FIGS. 2, 3 and 4, the cutting edges 11 of the

teeth

6, 7 and 8, which are mutually staggered perpendicular to the longitudinal axis 15 of the link 3, overlap one another when looked at in the direction of travel of the chain. These edges also extend parallel to the side faces of the link 3 and perpendicular to the longitudinal axis 15 thereof.

The outer teeth 8 have their cutting edges 11 projecting away from the trunk and beyond the tangent 18 to the two associated rollers 2, as shown in FIGS. 2 and 3. In this manner, jamming of the chain cutter 1 as it passes through the base ofa branch 19 is avoided, even though the chain debranches and debarks simultaneously, this jamming being otherwise liable to happen when the base 19 of the branch has a diameter which is larger than the width of the chain, as shown in FIG. 3. The cutting edge of outer tooth 8 thereby cuts the chain 1 free so that its unimpeded movement is insured. The axial movement of the chain unit in relation to the trunk 9 is indicated in FIG, 3 by arrow 20, the feed of the chain being at right angles thereto, or outward from the plane of the drawing.

The

teeth

6, 7 and 8 illustrated in FIGS. I to are solid teeth and have a height 2I which is always greater than 5 mm.

Preferably the

cutting teeth

6, 7 and 8 are formed, ground and mounted on the links 3 as shown in FIGS. 40 to 4!. The

teeth

6, 7 and 8 have a top rake 22 and an upper clearance angle 23 which are equal to approximately The inner teeth 6 and intermediate teeth 7 each have a clearance angle 24 on that side which faces the trunk from the cutting edge 11 to the foot of the tooth of approximately 5 or 2 18, a clearance angle 25 on that side which faces away from the trunk to the cutting edge I] to the foot ofthe tooth of approximately 29?, and on both sides with a clearance angle 26 from the cutting edge 11 in a direction opposite to the direction of travel of the chain of approximately 2%. The outer teeth 8 have a clearance angle 27 on that side which faces away from the trunk from the cutting edge 11 to the foot of the tooth of approximately 10, a lateral clearance angle 28 on that side which faces away from the trunk from the cutting edge 11 in a direction opposite to the direction of travel of approximately 5, and a lateral clearance angle 29 on that side which faces the trunk from the cutting edge ll opposite to the direction of travel of approximately 2%.

Links 3 with

cutting teeth

6, 7 and 8 could be distributed along the chain I so that there results an overall number of teeth of from 6 to 33 teeth per meter of chain length. In FIGS. 40, 4f, and 4i, arrows 30 show the axial movement of

teeth

6, 7 and 8 in relation to the trunk 9 to be treated, the feed of the chain, of course, being at right angles thereto, as shown by the arrows I0 and 17 in FIGS. I and 2, respectively.

The chain cutter of the present invention thus works effectively, insures trouble-free debarking and simultaneous debranching of trees of varying diameters, and neither has an inclination to cut into the trunk, nor to become jammed when passing through the bases of large branches.

It is to be understood that the chain cutter of the present invention can be mounted on, and driven by, any conventional mechanism. A particularly suitable mechanism is disclosed in applicants copending U.S. Pat. application Ser. No. 620,926 titled Apparatus for Transporting and Treating Trees, filed concurrently herewith.

Of course, variations of the specific construction and arrangement of this type chain cutter herein disclosed can be made by those skilled in the art without departing from the invention as defined in the appended claims.

We claim:

1. A chain cutter comprising a plurality of roller members adapted to engage an object to be cut, and a plurality of links connected with said roller members to form a link chain, wherein the improvement comprises a plurality of cutting teeth fixed to the outer links of one side face of said chain, at least one portion of some of said teeth each having a cutting edge projecting beyond its associated link towards said object, and terminating approximately at a point coincident with the point of engagement of an associated roller and said object.

2. The chain cutter of claim 1, wherein said plurality of cutting teeth is divided into three groups of teeth mutually staggered with respect to the longitudinal axes of said outer links.

3. The chain cutter of claim 1, wherein said teeth are solid.

4. The chain cutter of claim 1, wherein the cutting edge of each of said teeth extends parallel to the side faces of its corresponding outer links and perpendicular to the longitudinal axis thereof.

5. The chain cutter of claim I, wherein another portion of said teeth have cutting edges projecting away from the object to be cut, and beyond the outer surface of their associated rollers.

6. The chain cutter of claim 2, wherein cutting edges of said mutually staggered teeth overlap one another in a plane at right angles to the longitudinal axis of said chain.

7. The chain cutter of claim I, wherein the height of each of said teeth is at least 5 mm.

8. The chain cutter of claim 1, wherein the chain has from 6 to 33 teeth per meter oflength.

9. The chain cutter according to claim 2, wherein each of said staggered teeth have a top rake of approximately 10 and an upper clearance angle of approximately 10; wherein the inner tooth and intermediate tooth have, on that side facing said object, a clearance angle from the cutting edge to the foot of the tooth of approximately 5 and 2%, a clearance angle on the opposite side from said object from the cutting edge to the foot of the tooth of approximately 292, and on both sides with a clearance angle from the cutting edge in a direction opposite to the direction of travel of 2 A; and wherein the outer tooth has a clearance angle on the side facing said object from the cutting edge to the foot of the tooth of approximately 10, a lateral clearance angle on the side remote from said object from the cutting edge in a direction opposite to the direction of travel of approximately 5, and a lateral clearance angle on the side of said object from the cutting edge in a direction opposite the direction of travel of approximately 2%.

10. A chain cutter for debranching and debarking tree trunks, comprising a plurality of roller members adapted to engage the trunk, and a plurality of links connected with said roller members to form a link chain, wherein the improvement comprises a plurality of cutting teeth fixed to the outer links of one side face of said chain, one portion of each of said teeth having a cutting edge projecting beyond the associated link towards the trunk, and terminating approximately at a point which is coincident with the point of engagement of an associated roller and the trunk, for debarking said tree trunk; and another portion of said teeth having cutting edges projecting away from the trunk and beyond the outer surface of their associated rollers, for debranching the trunk.

Claims

3. The chain cutter of claim 1, wherein said teeth are solid.

5. The chain cutter of claim 1, wherein another portion of said teeth have cutting edges projecting away from the object to be cut, and beyond the outer surface of their associated rollers.

7. The chain cutter of claim 1, wherein the height of each of said teeth is at least 5 mm.

8. The chain cutter of claim 1, wherein the chain has from 6 to 33 teeth per meter of length.

9. The chain cutter according to claim 2, wherein each of said staggered teeth have a top rake of approximately 10* and an upper clearance angle of approximately 10*; wherein the inner tooth and intermediate tooth have, on that side facing said object, a clearance angle from the cutting edge to the foot of the tooth of approximately 5* and 2 1/2 *, a clearance angle on the opposite side from said object from the cutting edge to the foot of the tooth of approximately 2 1/2 *, and on both sides with a clearance angle from the cutting edge in a direction opposite to the direction of travel of 2 1/2 *; and wherein the outer tooth has a clearance angle on the side facing said object from the cutting edge to the foot of the tooth of approximately 10*, a lateral clearance angle on the side remote from said object from the cutting edge in a direction opposite to the direction of travel of approximately 5*, and a lateral clearance angle on the side of said object froM the cutting edge in a direction opposite the direction of travel of approximately 2 1/2 *.