CA1221005A - Tree felling head reciprocally mounted on boom mounting adapter - Google Patents

Abstract

A B S T R A C T

A tree felling head wherein an accumulator grapple and power-driven circular saw are mounted on a common frame, such frame being reciprocally mounted on a boom mounting adapter so that when the felling head is positioned adjacent a tree, the power-driven saw can be moved forwardly in a straight line path to make a cut through the tree whereafter the cut tree is gripped by the grapple and held in an upright position.

Description

1221 [)0S
Title of Invention:
Tree Felling Head Reciprocally Mounted on Boom Mounting Adapter.
Field of Inven-tion:
This invention relates to a felling head for harvesting standing trees, and more particularly to a felling head having a circular saw and grapple on a common frame that is reciprocally mounted on a frame structure or adapter attachable to the end of an extendible and retract-able boom and to a method of harvesting trees.sackground of Invention:
Tree felling heads are well known in the art and comprise in general the combination of a grapple and tree severing device. In some instances one or more finger arms are provided in addition to the grapple for accumulating several trees. The severing device is either a shear unit or a saw, the former being more popular in recent years, but because of fiber damage during severing, saw units are considered more suitable of the two. The saws known in the art are of two basic types, one being a chain saw and the other a circular saw blade. The latter was the earliest development in the art, but never gained any real popularity, perhaps because of the difficulty of preventing binding during cutting. Binding of the saw ~lade will occur if the saw blade is not moved in a straight-line path through the tree during cutting, and also in many cases, because of the tree resting on the blade after it has been cut.
In order to get straight-line movement of the saw during a severing operation, there have been a number of different proposals and, as examples of such, reference may *

- 2 - ~XlOOS

be had to ~ -~s~
~r ; United States Patent 2,538,371 issued January 16, 1951 to R. G. LeTourneau;
United States Patent 776,743 issued December 6, 1904 to F. Vaughn Holt; United States Patent 3,494,389 issued February 10, 1970 to J. L. Thiobodeau, and Canadian Patent 898,661 issued April 25, 1982 to Kockum Soderhamn Aktiebolag.
In each of United States Patents 776,743 and

3,494,389 the saw blade is reciprocally mounted and movable relative to a tree gripping means that holds the tree during the severing operation. In United States Patent 2,538,371 the saw unit is mounted on a horizontal beam which is reciprocally movable, and in Canadian Patent 898,661 the saw unit is mounted on a pair of parallel arms.
The parallel arms are used to raise and lower the severing device, but in such arrangement the boom cannot be used to mova the severing device toward and away from the vehicle, as can be done with an extendible and retractable boom. It is thus necessary to move the vehicle forwardly to effect a severing operation, and the same will result in binding of the saw because of the uneven terrain normally encountered in the forest over which the vehicle must travel.
Surnmarx of_Invention:
A principal object of the present invention is to provide a circular saw type felling head wherein the power driven saw and tree gripping grapple arms are mounted on a common frame reciprocally movable on an ~ 3 - 1~21005 adapter or coupling detachably connectable to the free end of an extendible and retractable boom.
A further object of the present invention is to provide a circular saw felling head of the foregoing type with a ground engaging plate below the circular saw to protect the same during use in field operations.
Another principal object of the present invention is to provide a circular saw felling head of the foregoing type with a butt plate on which the cut trees can rest after being severed from their roots at a position above the power-driven saw.
Another principal object of the present invention is to provide a circular saw felling head of the foregoing type with an accumulator-type grapple.
Another object of the present invention is to provide a circular saw felling head of the foregoing type with a side tilt mechanism.
In keeping with the foregoing, there is provided in accordance with one aspect of the present invention a tree felling head comprising: a frame having a grapple mounted thereon and a power-driven circular saw located therebelow; an adapter detachably mountable on the free end of an extendible and retractable boom; and means reciprocally mounting said frame on said adapter.
In accordance with another aspect of the present invention, there is provided a method of felling trees using a felling head having a circular saw and grapple means mounted on a common frame comprising the steps of: moving the felling head relative to the tree

- 4 - ~2~005 to pass the saw therethrough; severing the tree from its roots; positioning the butt end of the cut tree on a stationary butt plate mounted above the saw blade at a position below the cut made therethrough by the circular saw, and gripping the tree, after it has been cut, with the grapple to hold the tree in an upright position.
List of Drawings:
The invention is illustrated by way of example in the accompanying drawings, wherein:
Figure 1 is an oblique view of a felling head provided in accordance with the present invention;
Figure 2 is a side elevational view similar to Figure 1 illustrating a modified embodiment;
Figure 3 is a side elevational view illustrating a still further modified embodiment;
Figure 4, located on the same sheet of drawings as Figure 1, is a partial front elevational view of the felling head iliustrated in Figure 1 with portions removed for purposes of illustration.
Figure 5 is a plan view of a portion of the saw blade;
Figure 6 is a view taken along line 6-6 of Figure 5;
Figure 7 is a side elevational view of the lower end portion of the felling head of the type illustrated in Figure 1 but modified to provide means for side tilt of the felling head;

~ 5 ~ ~2 ~ 1 ~0 5 Figure 8 is a partial right hand elevational view of Figure 7;
Figure 9 is a partial left hand elevational view of Figure 7; and Figure 10 is an oblique view of the complete felling head portions of which are illustrated in Figures 7, 8 and 9.
Referring to the drawings, there is illustrated in the drawings a felling head comprising a vertical rigid box frame member 10, having an accumulator-type grapple 20 mounted thereon and a circular saw tree severing device 30 at the lower end of the frame. The frame 10 is reciprocally mounted on a boom mounting adapter 40.
The accumulator grapple 20 includes arms 21 and 22 pivotally mounted on the frame and movable by respective ones of a pair of hydraulic cylinders 23 (only one being illustrated in the drawing) and a tree holding arm 25 pivotally mounted as at 26 on the frame and movable by a hydraulic cylinder toward and away from an abutment 27 on the frame.
The tree holding arm is preferably an articulated arm permitting snaking it out from between trees held by the grapple arms during accumulation of several trees.
Accumulator grapples are well known in the art and further description of the same is deemed unnecessary as any known accumulator grapple may be used. For further information on accumulator grapples, reference may be had to the - 6 ~ O ~ S

following United States Patents:
3,911,981 issued October 14, 1975 3,910,326 issued October 7, 1975 3,~05,860 issued April 23, 1974 3,875,983 issued April 8, 1975.
On the upper end of the frame 10 there is a tree abutment member 11 and at the lower end there is an enlarged box section 12 in which is mounted an hydraulic motor for driving the circular saw. A plate 13 is secured to the lower end of the frame 10 and has a downwardly directed peripheral flange 14 circumscribing a majo~
portion of the periphery of the saw blade to protect the same during use. The plate 13, at the front, has a portion designated 13a which may be described as a butt plate and supports the butt end of the trees after they have been severed from their roots and in a position to be grasped by the grapple 20. On either side of the butt plate 13a there is an upstanding gusset plate 15 to assist in retaining the grasped trees in position.
The cwtting device 30 consists of a circular saw blade 31 made of relatively thin material, for example 3/8l1 thickness and the teeth are set to cut a wide kerf, for example 1~". The teeth are formed integrally with the blade with adjacent teeth being offset respectively in opposite directions, the upper teeth being designated 32 and the lower teeth 33. The teeth 32 offset upwardly extend above the upper surface of the butt plate 13a whereby the saw cut through the tree is at a vertical - 7 - ~ % ~ ~0 ~

elevation higher than the butt plate. After the tree has been severed from its roots it drops onto and is supported by the butt plate whereafter the tree is grasped by the grapple and retained therein with further trees being accumulated and grasped thereby as they are severed from their roots. The saw blade 31 is detachably mounted as by bolts 34 on a hub 35 secured to a shaft 36 journalled in the frame 10 by suitable bearing means 37. The saw shaft 36 is driven by an hydraulic motor 38 located within the box frame and thereby fully protected by the same.
The boom mounting adapter or bracket 40 is a rigid weldment having a boom mounting portion 42, a pair of channels 43 spaced apart from one another and located respectively on opposite sides of the frame 10 and projecting forwardly from the boom mounting portion 42.
Secured to the channel members 43 are four rigid box members 44, that project downwardly beyond the circular saw and secured to the terminal end thereof is a ground-engaging foot plate 45.
The frame 10 may be mounted in various differentways on the boom mounting bracket 40 for reciprocable movement, for example, by rollers to facilitate sliding of the frame on the bracket. In the embodiment illustrated in Figure ~, frame 10 is mounted on the boom mounting bracket 40 by respective upper and lower rollers 50 and 51 engaging the upper and lower surfaces of channels 43.
This arrangement, however, exposes the rollers to various - 8 - ~2~00S

debris encountered during field operations. In the embodiment illustrated in Figures 1, 4 and 7 to 10, channels 43 are U-shaped channels in face-to-face relation and provide a running track for rollers 52 suitably journalled by bearing means on the frame 10.
There are two rollers 52 on each of opposite sides of the frame, one roller being located behind the other.
The frame 10 is reciprocally movable on the boom mounting bracket by a pair of hydraulic cylinders 60 ~see Figure 2) mounted within the channels 43, in the case where the rollers ride on the upper and lower surface of the channel and at any other suitable location when the rollers are located within the channel. For example in Figure 1 the hydraulic cylinders may be located below respective ones of the channels 43 and anchored at opposite ends respectively to the boom mounting bracket portion 42 and at the other end to frame 10 or, as illustrated in Figures 8, 9 and 10, above channels 43.
The boom mounting bracket 40 is apertured, as at 46 to receive a pivot pin 47 mounting the felling head on the end of an extendible and retractable knuckle boom 100. A pair of levers 101 and 102 pivotally inter-connected as by pin 103 are connected respe~tively at opposite ends to the boom 100 and the felling head by pins 104 and 105. An hydraulic cylinder 106 is attached to the boom as by pivot pin 107 and at the other end to the pivot 103 interconnecting the levers. The arrangement accordingly, is such that the felling head can be pivoted ~L~2~)0S

from a vertical position as shown in Figure 1 to a horizontal position for felling the trees after they have been severed from their roots.
A modified embodiment of the invention is illustrated in Figure 3, wherein the ground-engaging foot plate 45 has been omitted from the boom adapter.
This arrangement, however, is not particularly desirable as there is no protection for the circular saw blade during use in field logging operations. Standing trees to be harvested may be located amongst dense undergrowth and in many instances in rocky terrain. During operation the boom is extended to a position adjacent a tree and lowered for severing the tree at an appropriate height.
While positioning, the felling head foot plate 45 forces dense undergrowth downwardly without any substantial damage to the same and at the same time prevents the driven circular saw from accidentally engaging rocks or the like in the vicinity of the tree to be severed.
During winter operation the foot plate is used to compact the snow at the tree to be cut and thus leave a relatively short stump. The foot plate also prevents creating effectively a snow storm at the tree. When the felling head is appropriately positioned, the operator, through suitable controls, actuates hydraulic cylinders 60 moving the frame 10 forwardly at an appropriate speed (for example a linear speed of 50 cm/sec) to pass the driven circular saw through the stem of the tree to cut the same. The saw moves sufficiently fast through the - 10 - :~2~1~0~

tree that the tree remains standing in an upright position and after being fully severed, drops onto the butt plate 13a. While the tree is still standing, the grapple arms are closed, grasping the tree holding it in the upright position while the felling head is moved to another tree for continuing the operation, several trees being accumulated depending upon the capacity of the accumulator grapple and the size of the butt plate 13a. The grapple holding arms (hydraulically operated) are synchronized to grasp the tree firmly only after the tree has been cut. secause of this there is no stress applied to the tree during cutting and thus no fiber damage. Also in most cases it elemininates the need of any side tilt action for the felling head. However, if desired, side tilt can be provided and such embodiment is illustrated in Figures 7, 8 and 9.
The saw blade is illustrated in more detail in Figures 5 and 6 and such blade is found to provide excellent results during field use. The blade is made from CHT360 steel 3/8" thick and the teeth formed by flame cutting, grinding and hammered to relieve stress.
The teeth are set to cut a 1~" kerf and during operation the blade is driven at a speed of 1000 R.P.M.
Referring to Figure 5, radii designated A B C
& D are respectively 25-3/8", 25-3/4", 26-3/4" and 27-3/8".
Angles designated E F and G are respectively 612", 20 and 10. Referring to Figure 6, angles H and J are each 30. Obviously, however, other designs of circular saw blades may be used.

lX2~L00~;

During tests it was found a thick blade was too heavy to drive and a blade with separate teeth became virtually toothless after one hour of cutting birch. A
saw blade made as per the foregoing and illustrated in Figures 5 and 6 has been found to perform satisfactorily for two weeks without sharpening.
The felling head illustrated in Figures 7 to 9 is the same as that illustrated in Figure 1 except the boom mounting adapter 40 is constxucted somewhat differently and has been modified so as to provide for side tilt of the felling head. In these Figures the same reference numerals have been used as in Figure 1 designating corresponding parts but as will be noted, more details of the construction of the boom mounting adapter are shown. In order to illustrate the adapter in more detail the upper end of frame 10 as well as the grapple 20 and accumulator arm 25 have been omitted.
Referring to Figures 7, 8 and 9, the boom mounting adapter 40 consists of a pair of U-shaped channels 43 disposed in face-to-face relation and are attached to the boom mounting adapter portion 42 by way of a pivot pin 70. The pair of U-shaped channels 43 are provided by respective upper and lower plates 43A
and 43~ spaced apart from one another and welded to respective ones of a pair of vertical plates 43C
disposed at opposite sides of the frame. The plates 43A
and 43B, although not illustrated, are U-shaped in plan view and the pair of plates are welded to an end plate - 12 - 12~05 71 having an aperture 72 therein :Eor receivi.ng pivot pin 70. The upper and lower plates 43A and 43B and side plates 43C are further welded to a generally C-shaped stirrup plate 73 apertured as at 74 to receive the pivot pin 70. The stirrup plate 73 has respective ones of a pair of apertures 75 through which respective ones of the pair of hydraulic cylinders 60 pass, such cylinders being secured at opposite ends thereof respectively as at 76 and 77 to the frame 10 and end plate 71.
The boom mounting portion of the adapter includes a pair of side plates 80 and 81 spaced apart from one another and welded to a base plate 82. The side plates 80 and 81 have respective ones of pairs of aligned apertures for receiving respective pivot pins 47 and 105. The base plate 82 has a sleeve 83 secured thereto by means of plates 84 and 85 reinforced by gusset members 86. The sleeve 83 is of such length as to fit between journals in the respective plates 71 and 73 ~0 that receive the pivot pin 70. The pivot axis of pivot pin 70 is perpendicular to the pivot axis of pin 47, the latter pin mounting the adapter on the end of an extendible and retractable boom. From the arrange-ment it can be clearly seen pivot axis 47 permits raising and lowering the felling head for severing the standing tree and felling the same to the ground and pivot pin 70 permits side tilt of the felling head for when the growing tree to be felled is not in an 1~2~ )S

upright or substantially upright position and/or when the vehicle is on terrain that slopes.
Tilting of the felling head is effected by a hydraulic c~linder unit 90 attached at opposite ends by pivot pins 91 and 92 to brackets 93 and 94; bracket 93 consisting of a pair of lugs secured to and project-ing from plate 81 and bracket 94 consisting of a pair of spaced apart plates secured to the upper and lower plates 43a and 43b and side plate 43c.

Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A tree felling head comprising: a frame having a power operated grapple mounted thereon and a power-driven circular saw located therebelow; an adapter detachably mountable on the free end of an extendible and retractable boom; means reciprocally mounting said frame on said adapter, and power means coacting with said frame and adapter to reciprocally move the frame on the adapter.

2. A tree felling head as defined in claim 1 wherein said adapter has a pair of spaced apart slide rails mounted thereon and located respectively one on opposite sides of said frame and means reciprocally mounting said frame on said slide rails.

3. A tree felling head as defined in claim 1 including a butt plate secured to said frame and located adjacent the top side of the blade portion of said circular saw to support the butt end of a tree after the tree has been severed from its root by said saw.

4. A tree felling head as defined in claim 1 including a first plate secured to said frame and overlying the upper surface of a selected portion of said circular saw and a second plate secured to said adapter and underlying said saw blade when the frame is in a retracted position on the adapter.

5. A tree felling head comprising:
(a) a vertical frame having a box-like structure at the lower end thereof;
(b) a power operated grapple mounted on said frame above said box-like structure;
(c) a motor mounted on said frame and located within said box-like structure;
(d) a horizontally disposed circular saw blade connected to a shaft driven by said motor, said saw blade being relatively thin with teeth around the periphery thereof that have a wide set;
(e) a plate secured to said frame and over-lying said blade exposing a selected number of teeth at the forward end of the felling head;
(f) a mounting adapter detachably mountable on the free end of an extendible and retractable boom;
(g) a pair of spaced apart rails secured to said adapter and projecting forwardly, said rails being located one on each of opposite sides of the box-like structure of said vertical frame;
(h) means reciprocally mounting the vertical frame on said rails for movement backwardly and forwardly, respectively, to a retracted position and tree cutting position; and (i) power means coacting with said adapter and frame for effecting reciprocal movement of the frame on the adapter.

6. A tree felling head as defined in claim 5 wherein said grapple is an accumulator type grapple.

7. A tree felling head as defined in claim 5 including a horizontal plate secured to said adapter and underlying said saw blade, when said frame is in a retracted position on said adapter.

8. A tree felling head as defined in claim 5 wherein said rails are U-shaped channel members disposed in face-to-face relation and wherein the frame mounting means of paragraph (h) comprise rollers journalled on said frame and in rolling contact with said channel members.

9. A method of felling a tree using a felling head having a power driven circular saw adjacent the lower end thereof, a butt plate overlying a portion of the saw, and tree gripping means disposed above the butt plate; said method comprising the steps of:
moving the power driven saw in a straight line path to cut through the tree with the upper part of the saw cut being at a higher elevation than the butt plate, allowing the butt end of the cut tree to drop onto the butt plate; and gripping the tree after it has been cut and still standing in an upright position on the butt plate.

10. A method as defined in claim 9 including the step of collecting a plurality of cut trees on the felling head in sequence as they are cut and dropped onto the butt plate.

11. A method of felling standing trees comprising the steps of: moving a felling head in a straight line horizontal path to cause a power driven circular saw to cut therethrough at an elevation at least as high as the upper surface of a butt plate on the felling head, allowing the butt end of the cut tree to drop onto the butt plate and thereafter while the tree is still in an upright position actuating power operated gripping means on the felling head to grip and hold the tree in its upright position.

12. Apparatus for use in felling standing trees comprising:
(a) a mobile carrier having an extendible and retractable boom mounted thereon;
(b) a felling head comprising a frame having a power driven circular saw and power operated tree gripping means mounted thereon for respectively making a horizontal cut through a standing tree and thereafter grip the tree to hold the same in an upright position;
(c) adapter means;
(d) means mounting said felling head on said adapter for reciprocal movement backwardly and forwardly along a straight line path;

(e) power means for moving said felling head on said adapter; and (f) means pivotally mounting said adapter on the free end of said extendible and retractable boom for control-lably felling trees cut from their roots.

13. A method of felling trees using a felling head having a power driven circular saw and grapple means mounted on a common frame comprising the steps of: moving the felling head, relative to the tree, to pass the power driven saw therethrough severing the tree from its roots and in so doing positioning the butt end of the cut tree above a stationary butt plate mounted above a portion of the saw blade on the felling head, supporting the butt end of the tree on the butt plate, and gripping the tree, after it has been severed, with the grapple to firmly retain the same on the butt plate.

14. The method as defined in claim 13 wherein said felling head is moved along a substantially horizontal straight line path.

15. A felling head as defined in claim 1 wherein said circular saw comprises a thin steel plate having teeth integrally formed therewith with adjacent teeth offset in opposite directions to provide a kerf within the range of 1" to 1?".

16. A circular saw blade as defined in claim 15 wherein the tooth depth is approximately 2" and wherein the outer surface of the tooth slopes approximately 10° to a tangent to the blade.

17. A circular saw blade as defined in claims 15 or 16, wherein the leading edge of each tooth is at an angle of approximtaely 20° to the radius of the blade.

18. A circular saw blade as defined in claim 16 wherein said outer surface of each tooth slopes approximately 30°
relative to a plane perpendicular to the outer flat surface of the tooth.

19. A tree felling head adapted to be mounted on a mobile carrier comprising: a frame; a power driven circular saw mounted on the lower end of said frame for rotation in a plane generally parallel to the ground when the head is mounted on the vehicle to cut through the trunk of a standing tree; a flat plate secured to said frame and overlying a selected portion of the circular saw for supporting the butt-end of a vertically disposed tree cut from its roots;
and, grapple means on said frame above said flat plate for gripping the tree after it has been cut by said saw.

20. A felling head as defined in claim 19 including a rigid upstanding gusset plate means projecting in a direction upwardly from said flat plate around a selected area thereof defining a tree butt end minimizing the tendency of a cut tree to topple off the butt-end receiving area on such plate and providing means preventing the butt end of trees from sliding off said plate.

21. A felling head as defined in claims 19 of 20 including a further plate underlying said circular saw.

22. A felling head as defined in claims 19 or 20 including a further plate underlying said circular saw end wherein said circular saw is mounted for reciprocal movement relative to said further plate and in a plane parallel thereto.