US3712350A

US3712350A - Limbing boom

Info

Publication number: US3712350A
Application number: US00168323A
Authority: US
Inventors: J Eynon
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-08-11
Filing date: 1971-08-02
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23
Also published as: CA873682A

Abstract

A limbing assembly for removing limbs from a stationary tree includes a base with a pair of parallel inner arms pivotally connected to the base. Means are provided for pivoting the inner arms relative to the base with means for maintaining the inner arms in their parallel relationship during such pivotal movement. A first arcuately-surfaced member is rigidly secured to one inner arm, a shaft is rotatably mounted in the other inner arm, and a second arcuately-surfaced member is rigidly secured to the shaft. The arcuate surfaces of the members are engaged with one another in driving relationship. An outer arm is rigidly secured at one end to the shaft. The outer arm has a length equal to the length of the other inner arm between the shaft and the base. A second shaft is rotatably mounted at the other end of the outer arm with a limbing head rigidly secured to the shaft. Means connecting the first and second shafts cause the second shaft to move through the same angle relative to the outer arm as the inner arms move relative to the base. Movement of the inner arms relative to the base causes the limbing head to travel in a straight line at a constant angular attitude relative to the base.

Description

United States Patent (1 1 Eynon mt 3,712,350 1 .ian.23, 1973 l 54] LIMBING BOOM [76] Inventor: John E. Eynon, l03 Sunset Bay,

Port Arthur, Ontario, Canada [22] Filed: Aug. 2, 1971 [2l] Appl. No.: 168,323

[51] Int. Cl. ..A0lg 23/02 [58] Field of Search ..l44/2 Z, 3 D, 34 R, 309 AC [S 6] References Cited UNITED STATES PATENTS 3,554,245 1/1971 Eynon ..l44/3 D Primary Examiner-Gerald A. Dost Attorney-Stevens, Davis, Miller & Mosher [57] ABSTRACT A limbing assembly for removing limbs from a stationary tree includes a base with a pair of parallel inner arms pivotally connected to the base. Means are provided for pivoting the inner arms relative to the base with means for maintaining the inner arms in their parallel relationship during such pivotal movement. A first arcuately-surfaced member is rigidly secured to one inner arm, a shaft is rotatably mounted in the other inner arm, and a second arcuately-surfaced member is rigidly secured to the shaft. The arm- .ate surfaces of the members are engaged with one another in driving relationship. An outer arm is rigidly secured at one end to the shaft. The outer arm has a length equal to the length of the other inner arm between the shaft and the base. A second shaft is rotatably mounted at the other end of the outer arm with a limbing head rigidly secured to the shaft. Means connecting the first and second shafts cause the second shaft to move through the same angle relative to the outer arm as the inner arms move relative to the base. Movement of the inner arms relative to the base causes the limbing head to travel in a straight line at a constant angular attitude relative to the base.

7 Claims, 4 Drawing Figures PATENTEDJAN 23 I975 SHEET 1 [IF 4 PATENTEDJAH23 197s sum 2 [1F 4 PATENTEDJAH 23 I973 SHEET 3 [IF 4 LIMBING BOOM This invention relates to limbing assemblies for removing limbs from trees.

The limbing of trees is frequently carried out by movement of a limbing head along the tree with a power sufficient to cause the limbing head to remove limbs from the tree when the limbing head engages the limbs, the limbing head usually having suitably shaped leading surfaces to facilitate detachment of the limbs from the tree. Various mechanisms have been proposed for moving the limbing head along the tree, but such known mechanisms have been somewhat cumbersome and hence not easy to transport from one place to another. Also, it has been a problem to effectively transmit the necessary power to the limbing head at all stages of its travel along the tree.

It is therefore an object of this invention to provide a limbing assembly which overcomes the above-mentioned disadvantages.

According to the invention, a limbing assembly includes a pair of parallel inner arms pivotally connected to a base. The inner arms pivotally carry and are linked to an outer arm in such a manner that, when the inner arms move through an angle relative to the base, the outer arm moves through twice the angle relative to the inner arms. The free end of the outer arm carries a limbing head, and a linkage connecting the limbing head and the inner arms ensures that, during the previously mentioned angular movement of the various arms, the limbing head moves angularly relative to the outer arm by the same amount that the inner arms move relatively to the base.

In this manner, angular movement of the inner arms relative to the base causes the limbing head to travel in a straight line at a constant angular attitude relative to the base.

One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, of which,

FIG. 1 is a side view of a limbing assembly in one position,

FIG. 2 is a similar view of the limbing assembly in another position, shown FIG. 3 is a front view of the limbing assembly in the position shown in FIG. 2, and

FIG. 4 is a side view of the limbing assembly in a third position.

Referring to the drawings, a limbing assembly includes a base 1 mounted on a chassis 2 of a logging machine. For ease of explanation, this embodiment will be described in connection with the limbing of a suitably held horizontal felled tree. However, it will be understood that the base 1 may be mounted on the by

shafts

9, 10 respectively. Thus the

arms

4,5, the links 8 and the portion of the base 1 between the

shafts

6,7 form a parallelogram linkage, with the result that the

arms

4,5 always remain parallel to each other during their angular movement relative to the base 1, and the links 8 always remain parallel to the line between the

shafts

6,7. Angular movement of the

arms

4,5 relative to the base 1 is effected by a hydraulic jack 11 having one end pivotally connected to the arm 4 by a pin 12 and the other end pivotally connected to the base 1 by a pin 13. The jack 11 passes through an aperture 14 in the arm 5.

The shaft 9 carries an outer arm unit 15 which includes an arm 16 equal in length to the

arms

4,5 and rigidly secured at one end to the shaft 9. The other end of the arm 16 carries a limbing head 17 for removing limbs from trees. The actual construction of the limbing head 17 is not a feature of this invention and will chassis for pivotal movement relative thereto so that the assembly can limb a tree at an inclined angle. The embodiment to be described may be used as the limbing assembly on the logging machine described in our Canadian Pat. No. 835,144 issued Feb. 24, I970 and entitled Feller-Limber-Buncher Logging Machine". It can also be used, when mounted in a position perpendicular to that shown, to limb a standing tree.

The base 1 carries an inner arm unit 3 formed by two spaced

parallel arms

4,5 pivotally connected at one end to the base 1 by

shafts

6,7 respectively and pivotally connected at the other end to opposite ends of links 8 therefore not be described further. However, a suitable limbing head is described in our patent application referred to above.

The limbing head 17 is rigidly secured to a shaft 18 rotatably mounted in the other end of the outer arm 16. The shaft 18 carries a sprocket 19 rigidly secured to the shaft 18, and an endless chain 20 passes around the sprocket 19 and around a sprocket 21 of the same size as the sprocket 19 carried by and rigidly secured to the shaft 9 at the opposite end of the arm 16. The shaft 9 is rotatably mounted in the arm 4 and links 8 and carries a gear segment 22 which is rigidly secured to the shaft 9. The gear segment 22 meshes with a similar gear segment 23 carried by and rigidly secured to the shaft 10, which in turn is rigidly secured to the arm 5.

In FIGS. 1, 2 and 4, the horizontal line 24 indicates a felled tree which is held by some convenient means (not shown) which may be, for example, the felling head described in our previously mentioned patent application. Assuming that the limbs of the tree 24 are to be removed by movement of the limbing head 17 from right to left, the jack 1 l is actuated to position the limbing assembly in the attitude shown in FIG. 1, and the limbing head 17 is engaged with the tree 24. If desired, the limbing head 17 may be capable of some initial angular adjustment relative to the tree 24 and to the shaft 18, for example by means of a linkage including a hydraulic jack. For the actual limbing operation however the limbing head 17 is effectively rigidly secured to the shaft 18. When the limbing head 17 has been suitably positioned with respect to the tree 24, the jack 11 is extended to cause the inner arm unit 3 to swing from the position shown in FIG. 1 through the central position shown in FIG. 2 to the position shown in FIG. 4. During this angular movement, the gear segment 22 is caused by its engagement with gear segment 23 to rotate about the axis of shaft 9, thereby rotating shaft 9 with consequent angular movement of the arm 16 relative to the inner arm unit 3 to cause the limbing head 17 to travel in a straight line along the tree. Also, the rotation of the shaft 9 causes a similar rotation of shaft 18, due to the connection by'chain 20, such that the felling head 17 moves angularly relative to the outer arm 16 so as to remain in the same angular attitude relative to the tree 24. In this way, the limbing head is moved along the tree 24, thereby removing its limbs. It will be seen that, as the

arms

4,5 move through an angle relative to the base 1, the arm 16 moves through twice this angle relative to the

arms

4,5, and the limbing head 17 moves through the original angle relative to the arm 16.

Iclaim:

1. A limbing assembly for removing limbs from a stationary tree, including a base, a pair of parallel inner arms pivotally connected to the base, means for pivoting the inner arms relative to the base, means for maintaining the inner arms in their parallel relationship during such pivotal movement, a first arcuately-surfaced member rigidly secured to one inner arm, a shaft rotatably mounted in the other inner arm, a second arcuately-surfaced member rigidly secured to said shaft, the arcuate surfaces of said members being engaged with one another in driving relationship, an outer arm rigidly secured at one end to the shaft, the outer arm having a length equal to the length of said other inner arm between said shaft and the base, a second shaft rotatably mounted at the other end of the outer arm, a limbing head rigidly secured to said shaft, and means connecting said first and second shafts cause the second shaft to move through the same angle relative to the outer arm as the inner arms move relative to the base, whereby movement of the inner arms relative to the base causes the limbing head to travel in a straight line at a constant angular attitude relative to the base,

2. A limbing assembly according to claim 1 where each arcuately-surfaced member is a gear segment 3. A limbing assembly according to claim 1 wherein the inner arms are maintained in parallel relationship by a link having opposite ends pivotally connected to the arms.

4. A limbing assembly according to claim 3 wherein shaft and at the other end on a third shaft carried by said one inner arm.

5. A limbing assembly according to claim 4 wherein the first arcuately-surfaced member is rigidly secured to said third shaft, and said third shaft is rigidly secured to said one inner arm.

6. A limbing assembly according to claim 1 wherein the means for pivoting the inner arms includes a hydraulic jack pivotally connected at one end to one of the inner arms and at the other end to the base.

7. A limbing assembly according to claim 1 wherein said means connecting said first and second shafts includes a first sprocket rigidly secured to the first shaft, a second sprocket rigidly secured to the second shaft, and an endless chain passing around said sprockets.

Claims

1. A limbing assembly for removing limbs from a stationary tree, including a base, a pair of parallel inner arms pivotally connected to the base, means for pivoting the inner arms relative to the base, means for maintaining the inner arms in their parallel relationship during such pivotal movement, a first arcuately-surfaced member rigidly secured to one inner arm, a shaft rotatably mounted in the other inner arm, a second arcuately-surfaced member rigidly secured to said shaft, the arcuate surfaces of said members being engaged with one another in driving relationship, an outer arm rigidly secured at one end to the shaft, the outer arm having a length equal to the length of said other inner arm between said shaft and the base, a second shaft rotatably mounted at the other end of the outer arm, a limbing head rigidly secured to said shaft, and means connecting said first and second shafts cause the second shaft to move through the same angle relative to the outer arm as the inner arms move relative to the base, whereby movement of the inner arms relative to the base causes the limbing head to travel in a straight line at a constant angular attitude relative to the base.

2. A limbing assembly according to claim 1 where each arcuately-surfaced member is a gear segment

3. A limbing assembly according to claim 1 wherein the inner arms are maintained in parallel relationship by a link having opposite ends pivotally connected to the arms.

4. A limbing assembly according to claim 3 wherein the link is pivotally mounted at one end on said first shaft and at the other end on a third shaft carried by said one inner arm.